doc: update NEWS

sys_macosx: don't require clock_gettime()
Earlier versions of macOS do not provide clock_gettime(). This patch checks for clock_gettime() at run-time and falls back to gettimeofday() if the symbol is not present.
2025-12-03 18:45:07 -05:00 · 2020-03-16 13:16:14 +01:00 · 2020-03-16 11:35:56 +01:00 · 2020-03-12 14:25:21 +01:00 · 2020-03-12 14:07:12 +01:00 · 2020-03-12 14:07:12 +01:00
217 changed files with 24047 additions and 6290 deletions
--- a/.gitignore
+++ b/.gitignore
@@ -1,9 +1,12 @@
 .deps
 .vimrc
+*.gcda
+*.gcno
 *.o
 *.swp
 *.dSYM
 *.DS_Store
+core.*
 tags
 /RELEASES
 /Makefile
--- a/Makefile.in
+++ b/Makefile.in
@@ -21,62 +21,56 @@
 #
 # Makefile template

-SYSCONFDIR=@SYSCONFDIR@
-BINDIR=@BINDIR@
-SBINDIR=@SBINDIR@
-LOCALSTATEDIR=@LOCALSTATEDIR@
-CHRONYVARDIR=@CHRONYVARDIR@
+SYSCONFDIR = @SYSCONFDIR@
+BINDIR = @BINDIR@
+SBINDIR = @SBINDIR@
+LOCALSTATEDIR = @LOCALSTATEDIR@
+CHRONYVARDIR = @CHRONYVARDIR@
+DESTDIR =

 CC = @CC@
 CFLAGS = @CFLAGS@
 CPPFLAGS = @CPPFLAGS@
+LDFLAGS = @LDFLAGS@

-DESTDIR=
-
-HASH_OBJ = @HASH_OBJ@
+EXTRA_OBJS = @EXTRA_OBJS@

 OBJS = array.o cmdparse.o conf.o local.o logging.o main.o memory.o \
-       reference.o regress.o rtc.o sched.o sources.o sourcestats.o stubs.o \
-       sys.o smooth.o tempcomp.o util.o $(HASH_OBJ)
+       reference.o regress.o rtc.o samplefilt.o sched.o socket.o sources.o sourcestats.o \
+       stubs.o smooth.o sys.o sys_null.o tempcomp.o util.o $(EXTRA_OBJS)

-EXTRA_OBJS=@EXTRA_OBJECTS@
+EXTRA_CLI_OBJS = @EXTRA_CLI_OBJS@

 CLI_OBJS = array.o client.o cmdparse.o getdate.o memory.o nameserv.o \
-           pktlength.o util.o $(HASH_OBJ)
+           pktlength.o socket.o util.o $(EXTRA_CLI_OBJS)

-ALL_OBJS = $(OBJS) $(EXTRA_OBJS) $(CLI_OBJS)
+ALL_OBJS = $(OBJS) $(CLI_OBJS)

-LDFLAGS = @LDFLAGS@
 LIBS = @LIBS@
-
-EXTRA_LIBS=@EXTRA_LIBS@
-EXTRA_CLI_LIBS=@EXTRA_CLI_LIBS@
+EXTRA_LIBS = @EXTRA_LIBS@
+EXTRA_CLI_LIBS = @EXTRA_CLI_LIBS@

 # Until we have a main procedure we can link, just build object files
 # to test compilation

 all : chronyd chronyc

-chronyd : $(OBJS) $(EXTRA_OBJS)
-	$(CC) $(CFLAGS) -o chronyd $(OBJS) $(EXTRA_OBJS) $(LDFLAGS) $(LIBS) $(EXTRA_LIBS)
+chronyd : $(OBJS)
+	$(CC) $(CFLAGS) -o chronyd $(OBJS) $(LDFLAGS) $(LIBS) $(EXTRA_LIBS)

 chronyc : $(CLI_OBJS)
 	$(CC) $(CFLAGS) -o chronyc $(CLI_OBJS) $(LDFLAGS) $(LIBS) $(EXTRA_CLI_LIBS)

-client.o : client.c
-	$(CC) $(CFLAGS) $(CPPFLAGS) @READLINE_COMPILE@ -c $<
-
-$(HASH_OBJ) : $(patsubst %.o,%.c,$(HASH_OBJ))
-	$(CC) $(CFLAGS) $(CPPFLAGS) @HASH_COMPILE@ -c $<
-
 distclean : clean
-	-rm -f .DS_Store
-	-rm -f Makefile config.h config.log
 	$(MAKE) -C doc distclean
 	$(MAKE) -C test/unit distclean
+	-rm -f .DS_Store
+	-rm -f Makefile config.h config.log

 clean :
-	-rm -f *.o *.s chronyc chronyd core *~
+	$(MAKE) -C test/unit clean
+	-rm -f *.o *.s chronyc chronyd core.* *~
+	-rm -f *.gcda *.gcno
 	-rm -rf .deps
 	-rm -rf *.dSYM

@@ -115,9 +109,18 @@ install-docs :
 %.s : %.c
 	$(CC) $(CFLAGS) $(CPPFLAGS) -S $<

-check : chronyd chronyc
+quickcheck : chronyd chronyc
 	$(MAKE) -C test/unit check
 	cd test/simulation && ./run
+	cd test/system && ./run
+
+check : chronyd chronyc
+	$(MAKE) -C test/unit check
+	cd test/simulation && ./run -i 20 -m 2
+	cd test/system && ./run
+
+print-chronyd-objects :
+	@echo $(OBJS)

 Makefile : Makefile.in configure
 	@echo
--- a/179
+++ b/179
@@ -1,3 +1,182 @@
+New in version 4.0
+==================
+
+Enhancements
+------------
+* Add support for Network Time Security (NTS) authentication
+* Add support for AES-CMAC keys (AES128, AES256) with Nettle
+* Add support for maxsamples of 1 for faster update with -q/-Q option
+* Add -L option to limit log messages by severity
+* Avoid replacing NTP sources with unreachable addresses
+* Improve NTP loop test to prevent synchronisation to itself
+* Update clock synchronisation status and leap status more frequently
+* Update seccomp filter
+* Add "add pool" command
+* Add -N option and sourcename command to print original names of sources
+* Add -a option to source/sourcestats command to print unresolved sources
+* Add reset command to drop all measurements
+
+Bug fixes
+---------
+* Handle RTCs that don't support interrupts
+* Respond to command requests with correct address on multihomed hosts
+
+Removed features
+----------------
+* Drop support for RIPEMD keys (RMD128, RMD160, RMD256, RMD320)
+
+New in version 3.5
+==================
+
+Enhancements
+------------
+* Add support for more accurate reading of PHC on Linux 5.0
+* Add support for hardware timestamping on interfaces with read-only
+  timestamping configuration
+* Add support for memory locking and real-time priority on FreeBSD,
+  NetBSD, Solaris
+* Update seccomp filter to work on more architectures
+* Validate refclock driver options
+
+Bug fixes
+---------
+* Fix bindaddress directive on FreeBSD
+* Fix transposition of hardware RX timestamp on Linux 4.13 and later
+* Fix building on non-glibc systems
+
+New in version 3.4
+==================
+
+Enhancements
+------------
+* Add filter option to server/pool/peer directive
+* Add minsamples and maxsamples options to hwtimestamp directive
+* Add support for faster frequency adjustments in Linux 4.19
+* Change default pidfile to /var/run/chrony/chronyd.pid to allow
+  chronyd without root privileges to remove it on exit
+* Disable sub-second polling intervals for distant NTP sources
+* Extend range of supported sub-second polling intervals
+* Get/set IPv4 destination/source address of NTP packets on FreeBSD
+* Make burst options and command useful with short polling intervals
+* Modify auto_offline option to activate when sending request failed
+* Respond from interface that received NTP request if possible
+* Add onoffline command to switch between online and offline state
+  according to current system network configuration
+* Improve example NetworkManager dispatcher script
+
+Bug fixes
+---------
+* Avoid waiting in Linux getrandom system call
+* Fix PPS support on FreeBSD and NetBSD
+
+New in version 3.3
+==================
+
+Enhancements
+------------
+* Add burst option to server/pool directive
+* Add stratum and tai options to refclock directive
+* Add support for Nettle crypto library
+* Add workaround for missing kernel receive timestamps on Linux
+* Wait for late hardware transmit timestamps
+* Improve source selection with unreachable sources
+* Improve protection against replay attacks on symmetric mode
+* Allow PHC refclock to use socket in /var/run/chrony
+* Add shutdown command to stop chronyd
+* Simplify format of response to manual list command
+* Improve handling of unknown responses in chronyc
+
+Bug fixes
+---------
+* Respond to NTPv1 client requests with zero mode
+* Fix -x option to not require CAP_SYS_TIME under non-root user
+* Fix acquisitionport directive to work with privilege separation
+* Fix handling of socket errors on Linux to avoid high CPU usage
+* Fix chronyc to not get stuck in infinite loop after clock step
+
+New in version 3.2
+==================
+
+Enhancements
+------------
+* Improve stability with NTP sources and reference clocks
+* Improve stability with hardware timestamping
+* Improve support for NTP interleaved modes
+* Control frequency of system clock on macOS 10.13 and later
+* Set TAI-UTC offset of system clock with leapsectz directive
+* Minimise data in client requests to improve privacy
+* Allow transmit-only hardware timestamping
+* Add support for new timestamping options introduced in Linux 4.13
+* Add root delay, root dispersion and maximum error to tracking log
+* Add mindelay and asymmetry options to server/peer/pool directive
+* Add extpps option to PHC refclock to timestamp external PPS signal
+* Add pps option to refclock directive to treat any refclock as PPS
+* Add width option to refclock directive to filter wrong pulse edges
+* Add rxfilter option to hwtimestamp directive
+* Add -x option to disable control of system clock
+* Add -l option to log to specified file instead of syslog
+* Allow multiple command-line options to be specified together
+* Allow starting without root privileges with -Q option
+* Update seccomp filter for new glibc versions
+* Dump history on exit by default with dumpdir directive
+* Use hardening compiler options by default
+
+Bug fixes
+---------
+* Don't drop PHC samples with low-resolution system clock
+* Ignore outliers in PHC tracking, RTC tracking, manual input
+* Increase polling interval when peer is not responding
+* Exit with error message when include directive fails
+* Don't allow slash after hostname in allow/deny directive/command
+* Try to connect to all addresses in chronyc before giving up
+
+New in version 3.1
+==================
+
+Enhancements
+------------
+* Add support for precise cross timestamping of PHC on Linux
+* Add minpoll, precision, nocrossts options to hwtimestamp directive
+* Add rawmeasurements option to log directive and modify measurements
+  option to log only valid measurements from synchronised sources
+* Allow sub-second polling interval with NTP sources
+
+Bug fixes
+---------
+* Fix time smoothing in interleaved mode
+
+New in version 3.0
+==================
+
+Enhancements
+------------
+* Add support for software and hardware timestamping on Linux
+* Add support for client/server and symmetric interleaved modes
+* Add support for MS-SNTP authentication in Samba
+* Add support for truncated MACs in NTPv4 packets
+* Estimate and correct for asymmetric network jitter
+* Increase default minsamples and polltarget to improve stability
+  with very low jitter
+* Add maxjitter directive to limit source selection by jitter
+* Add offset option to server/pool/peer directive
+* Add maxlockage option to refclock directive
+* Add -t option to chronyd to exit after specified time
+* Add partial protection against replay attacks on symmetric mode
+* Don't reset polling interval when switching sources to online state
+* Allow rate limiting with very short intervals
+* Improve maximum server throughput on Linux and NetBSD
+* Remove dump files after start
+* Add tab-completion to chronyc with libedit/readline
+* Add ntpdata command to print details about NTP measurements
+* Allow all source options to be set in add server/peer command
+* Indicate truncated addresses/hostnames in chronyc output
+* Print reference IDs as hexadecimal numbers to avoid confusion with
+  IPv4 addresses
+
+Bug fixes
+---------
+* Fix crash with disabled asynchronous name resolving
+
 New in version 2.4.1
 ====================

--- a/160
+++ b/160
@@ -4,7 +4,7 @@ What is chrony?
 ===============

 chrony is a versatile implementation of the Network Time Protocol (NTP).
-It can synchronize the system clock with NTP servers, reference clocks
+It can synchronise the system clock with NTP servers, reference clocks
 (e.g. GPS receiver), and manual input using wristwatch and keyboard.
 It can also operate as an NTPv4 (RFC 5905) server and peer to provide
 a time service to other computers in the network.
@@ -14,10 +14,10 @@ intermittent network connections, heavily congested networks, changing
 temperatures (ordinary computer clocks are sensitive to temperature),
 and systems that do not run continuosly, or run on a virtual machine.

-Typical accuracy between two machines on a LAN is in tens, or a few
-hundreds, of microseconds; over the Internet, accuracy is typically
-within a few milliseconds.  With a good hardware reference clock
-sub-microsecond accuracy is possible.
+Typical accuracy between two machines synchronised over the Internet is
+within a few milliseconds; on a LAN, accuracy is typically in tens of
+microseconds.  With hardware timestamping, or a hardware reference clock,
+sub-microsecond accuracy may be possible.

 Two programs are included in chrony, chronyd is a daemon that can be
 started at boot time and chronyc is a command-line interface program
@@ -27,7 +27,7 @@ operating parameters whilst it is running.
 What will chrony run on?
 ========================

-The software is known to work on Linux, FreeBSD, NetBSD, Mac OS X and
+The software is known to work on Linux, FreeBSD, NetBSD, macOS and
 Solaris.  Closely related systems may work too.  Any other system will
 likely require a porting exercise.  You would need to start from one
 of the existing system-specific drivers and look into the quirks of
@@ -37,20 +37,16 @@ How do I set it up?
 ===================

 The file INSTALL gives instructions.  On supported systems the
-compilation process should be automatic.
-
-You will need an ANSI C compiler -- gcc is recommended.
-
-The manual (in texinfo and text formats) describes how to set the
-software up for the less straightforward cases.
+compilation process should be automatic.  You will need a C compiler,
+e.g. gcc or clang.

 What documentation is there?
 ============================

-A manual is supplied in Texinfo format (chrony.texi) and
-ready-formatted plain text (chrony.txt) in the distribution.
+The distribution includes manual pages and a document containing
+Frequently Asked Questions (FAQ).

-There is also information available on the chrony web pages, accessible
+The documentation is also available on the chrony web pages, accessible
 through the URL 

    https://chrony.tuxfamily.org/
@@ -95,19 +91,12 @@ License

 chrony is distributed under the GNU General Public License version 2.

-
-Author
-======
+Authors
+=======

 Richard P. Curnow <rc@rc0.org.uk>
-
-
-Maintainers
-===========
-
 Miroslav Lichvar <mlichvar@redhat.com>

-
 Acknowledgements
 ================

@@ -118,131 +107,58 @@ implementation has been used to check the details of the protocol.
 The following people have provided patches and other major contributions
 to the program :

+Lonnie Abelbeck <lonnie@abelbeck.com>
 Benny Lyne Amorsen <benny@amorsen.dk>
-    Patch to add minstratum option
-
 Andrew Bishop <amb@gedanken.demon.co.uk>
-    Fixes for bugs in logging when in daemon mode
-    Fixes for compiler warnings
-    Robustness improvements for drift file
-    Improve installation (directory checking etc)
-    Entries in contrib directory
-    Improvements to 'sources' and 'sourcestats' output from chronyc
-    Improvements to documentation
-    Investigation of required dosynctodr behaviour for various Solaris
-      versions.
-
+Vincent Blut <vincent.debian@free.fr>
 Stephan I. Boettcher <stephan@nevis1.columbia.edu>
-    Entries in contrib directory
-
+Goswin Brederlow <brederlo@informatik.uni-tuebingen.de>
+Leigh Brown <leigh@solinno.co.uk>
 Erik Bryer <ebryer@spots.ab.ca>
-    Entries in contrib directory
-
+Jonathan Cameron <jic23@cam.ac.uk>
 Bryan Christianson <bryan@whatroute.net>
-    Support for Mac OS X
-    Support for privilege separation
-    Entries in contrib directory
-
 Juliusz Chroboczek <jch@pps.jussieu.fr>
-    Fix install rule in Makefile if chronyd file is in use.
-
+Christian Ehrhardt <christian.ehrhardt@canonical.com>
 Paul Elliott <pelliott@io.com>
-    DNSchrony (in contrib directory), a tool for handling NTP servers
-    with variable IP addresses.
-
+Stefan R. Filipek <srfilipek@gmail.com>
 Mike Fleetwood <mike@rockover.demon.co.uk>
-    Fixes for compiler warnings
-
 Alexander Gretencord <arutha@gmx.de>
-    Changes to installation directory system to make it easier for
-    package builders.
-
 Andrew Griffiths <agriffit@redhat.com>
-    Patch to add support for seccomp filter
-
 Walter Haidinger <walter.haidinger@gmx.at>
-    Providing me with login access to a Linux installation where v1.12
-    wouldn't compile, so I could develop the fixes for v1.13.  Also, for
-    providing the disc space so I can keep an independent backup of the
-    sources.
-
 Juergen Hannken-Illjes <hannken@eis.cs.tu-bs.de>
-    Port to NetBSD
-
 John Hasler <john@dhh.gt.org>
-    Project and website at tuxfamily.org
-    Changes to support 64 bit machines (i.e. those where
-      sizeof(unsigned long) > 4)
-    Bug fix to initstepslew directive
-    Fix to remove potential buffer overrun errors.
-    Memory locking and real-time scheduler support
-    Fix fault where chronyd enters an endless loop
-
 Tjalling Hattink <t.hattink@fugro.nl>
-    Fix scheduler to allow stepping clock from timeout handler
-    Patch to take leap second in PPS refclock from locked source
-    Patch to make reading of RTC for initial trim more reliable
-
 Liam Hatton <me@liamhatton.com>
-    Advice on configuring for Linux on PPC
-
 Jachym Holecek <jakym@volny.cz>
-    Patch to make Linux real time clock work with devfs
-
 Håkan Johansson <f96hajo@chalmers.se>
-    Patch to avoid large values in sources and sourcestats output
-
 Jim Knoble <jmknoble@pobox.com>
-    Fixes for compiler warnings
-
 Antti Jrvinen <costello@iki.fi>
-    Advice on configuring for BSD/386
-
-Miroslav Lichvar <mlichvar@redhat.com>
-    Reference clock support
-    IPv6 support
-    Linux capabilities support
-    Leap second support
-    Improved source selection
-    Improved sample history trimming
-    Improved polling interval adjustment
-    Improved stability with temporary asymmetric delays
-    Temperature compensation
-    Many other bug fixes and improvements
-
+Eric Lammerts <eric@lammerts.org>
+Stefan Lucke <stefan@lucke.in-berlin.de>
+Victor Lum <viclum@vanu.com>
+Kevin Lyda <kevin@ie.suberic.net>
+Paul Menzel <paulepanter@users.sourceforge.net>
+Vladimir Michl <vladimir.michl@seznam.cz>
 Victor Moroz <vim@prv.adlum.ru>
-    Patch to support Linux with HZ!=100
-
 Kalle Olavi Niemitalo  <tosi@stekt.oulu.fi>
-    acquisitionport support
-
 Frank Otto <sandwichmacher@web.de>
-    Handling arbitrary HZ values
-
+Denny Page <dennypage@me.com>
+Chris Perl <cperl@janestreet.com>
 Gautier PHILIPPON <gautier.philippon@ensimag.grenoble-inp.fr>
-    Patch to add refresh command to chronyc
-
 Andreas Piesk <apiesk@virbus.de>
-    Patch to make chronyc use the readline library if available
-
+Andreas Steinmetz <ast@domdv.de>
+NAKAMURA Takumi <takumi@ps.sakura.ne.jp>
 Timo Teras <timo.teras@iki.fi>
-    Patch to reply correctly on multihomed hosts
-
+Bill Unruh <unruh@physics.ubc.ca>
 Stephen Wadeley <swadeley@redhat.com>
-    Improvements to man pages
-
+Bernhard Weiss <lisnablagh@web.de>
 Wolfgang Weisselberg <weissel@netcologne.de>
-    Entries in contrib directory
-
+Bernhard M. Wiedemann <bwiedemann@suse.de>
+Joachim Wiedorn <ad_debian@joonet.de>
 Ralf Wildenhues <Ralf.Wildenhues@gmx.de>
-    Many robustness and security improvements
-    
-Ulrich Windl <ulrich.windl@rz.uni-regensburg.de> for the
-    Providing me with information about the Linux 2.2 kernel
-    functionality compared to 2.0.
-
+Ulrich Windl <ulrich.windl@rz.uni-regensburg.de>
 Doug Woodward <dougw@whistler.com>
-    Advice on configuring for Solaris 2.8 on x86
+Thomas Zajic <zlatko@zlatko.fdns.net>

-Many other people have contributed bug reports and suggestions.  I'm
-sorry I can't identify all of you individually.
+Many other people have contributed bug reports and suggestions.  We are sorry
+we cannot identify all of you individually.
--- a/addressing.h
+++ b/addressing.h
@@ -30,27 +30,36 @@
 #include "sysincl.h"

 /* This type is used to represent an IPv4 address or IPv6 address.
+   Addresses which are not resolved yet can be represented with an ID.
   All parts are in HOST order, NOT network order. */

 #define IPADDR_UNSPEC 0
 #define IPADDR_INET4 1
 #define IPADDR_INET6 2
+#define IPADDR_ID 3

 typedef struct {
  union { 
    uint32_t in4;
    uint8_t in6[16];
+    uint32_t id;
  } addr;
  uint16_t family;
+  uint16_t _pad;
 } IPAddr;

 typedef struct {
  IPAddr ip_addr;
-  unsigned short port;
-} NTP_Remote_Address;
+  uint16_t port;
+} IPSockAddr;
+
+typedef IPSockAddr NTP_Remote_Address;
+
+#define INVALID_IF_INDEX -1

 typedef struct {
  IPAddr ip_addr;
+  int if_index;
  int sock_fd;
 } NTP_Local_Address;

--- a/addrfilt.c
+++ b/addrfilt.c
@@ -247,6 +247,8 @@ set_subnet_(ADF_AuthTable table,
          set_subnet(&table->base6, ip6, 4, 0, new_state, delete_children) == ADF_SUCCESS)
        return ADF_SUCCESS;
      break;
+    default:
+      break;
  }

  return ADF_BADSUBNET;
@@ -359,9 +361,9 @@ ADF_IsAllowed(ADF_AuthTable table,
    case IPADDR_INET6:
      split_ip6(ip_addr, ip6);
      return check_ip_in_node(&table->base6, ip6);
+    default:
+      return 0;
  }
-
-  return 0;
 }

 /* ================================================== */
--- a/array.c
+++ b/array.c
@@ -66,8 +66,6 @@ ARR_DestroyInstance(ARR_Instance array)
 static void
 realloc_array(ARR_Instance array, unsigned int min_size)
 {
-  size_t data_size;
-
  assert(min_size <= 2 * min_size);
  if (array->allocated >= min_size && array->allocated <= 2 * min_size)
    return;
@@ -79,10 +77,7 @@ realloc_array(ARR_Instance array, unsigned int min_size)
    array->allocated = min_size;
  }

-  data_size = (size_t)array->elem_size * array->allocated;
-  assert(data_size / array->elem_size == array->allocated);
-
-  array->data = Realloc(array->data, data_size);
+  array->data = Realloc2(array->data, array->allocated, array->elem_size);
 }

 void *
--- a/candm.h
+++ b/candm.h
@@ -94,14 +94,24 @@
 #define REQ_SERVER_STATS 54
 #define REQ_CLIENT_ACCESSES_BY_INDEX2 55
 #define REQ_LOCAL2 56
-#define N_REQUEST_TYPES 57
+#define REQ_NTP_DATA 57
+#define REQ_ADD_SERVER2 58
+#define REQ_ADD_PEER2 59
+#define REQ_ADD_SERVER3 60
+#define REQ_ADD_PEER3 61
+#define REQ_SHUTDOWN 62
+#define REQ_ONOFFLINE 63
+#define REQ_ADD_SOURCE 64
+#define REQ_NTP_SOURCE_NAME 65
+#define REQ_RESET 66
+#define N_REQUEST_TYPES 67

-/* Structure used to exchange timevals independent on size of time_t */
+/* Structure used to exchange timespecs independent of time_t size */
 typedef struct {
  uint32_t tv_sec_high;
  uint32_t tv_sec_low;
  uint32_t tv_nsec;
-} Timeval;
+} Timespec;

 /* This is used in tv_sec_high for 32-bit timestamps */
 #define TV_NOHIGHSEC 0x7fffffff
@@ -200,12 +210,12 @@ typedef struct {
 } REQ_Modify_Makestep;

 typedef struct {
-  Timeval ts;
+  Timespec ts;
  int32_t EOR;
 } REQ_Logon;

 typedef struct {
-  Timeval ts;
+  Timespec ts;
  int32_t EOR;
 } REQ_Settime;

@@ -238,6 +248,11 @@ typedef struct {
  int32_t EOR;
 } REQ_Ac_Check;

+/* Source types in NTP source requests */
+#define REQ_ADDSRC_SERVER 1
+#define REQ_ADDSRC_PEER 2
+#define REQ_ADDSRC_POOL 3
+
 /* Flags used in NTP source requests */
 #define REQ_ADDSRC_ONLINE 0x1
 #define REQ_ADDSRC_AUTOOFFLINE 0x2
@@ -246,17 +261,34 @@ typedef struct {
 #define REQ_ADDSRC_NOSELECT 0x10
 #define REQ_ADDSRC_TRUST 0x20
 #define REQ_ADDSRC_REQUIRE 0x40
+#define REQ_ADDSRC_INTERLEAVED 0x80
+#define REQ_ADDSRC_BURST 0x100
+#define REQ_ADDSRC_NTS 0x200

 typedef struct {
-  IPAddr ip_addr;
+  uint32_t type;
+  int8_t name[256];
  uint32_t port;
  int32_t minpoll;
  int32_t maxpoll;
  int32_t presend_minpoll;
+  uint32_t min_stratum;
+  uint32_t poll_target;
+  uint32_t version;
+  uint32_t max_sources;
+  int32_t min_samples;
+  int32_t max_samples;
  uint32_t authkey;
+  uint32_t nts_port;
  Float max_delay;
  Float max_delay_ratio;
+  Float max_delay_dev_ratio;
+  Float min_delay;
+  Float asymmetry;
+  Float offset;
  uint32_t flags;
+  int32_t filter_length;
+  uint32_t reserved[3];
  int32_t EOR;
 } REQ_NTP_Source;

@@ -309,6 +341,16 @@ typedef struct {
  int32_t EOR;
 } REQ_SmoothTime;

+typedef struct {
+  IPAddr ip_addr;
+  int32_t EOR;
+} REQ_NTPData;
+
+typedef struct {
+  IPAddr ip_addr;
+  int32_t EOR;
+} REQ_NTPSourceName;
+
 /* ================================================== */

 #define PKT_TYPE_CMD_REQUEST 1
@@ -345,8 +387,9 @@ typedef struct {
   domain socket.

   Version 6 (no authentication) : changed format of client accesses by index
-   (using new request/reply types), new flags in NTP source request and report,
-   new commands: refresh, serverstats
+   (using new request/reply types) and manual timestamp, added new fields and
+   flags to NTP source request and report, made length of manual list constant,
+   added new commands: ntpdata, refresh, serverstats, shutdown
 */

 #define PROTO_VERSION_NUMBER 6
@@ -409,6 +452,8 @@ typedef struct {
    REQ_ManualDelete manual_delete;
    REQ_ReselectDistance reselect_distance;
    REQ_SmoothTime smoothtime;
+    REQ_NTPData ntp_data;
+    REQ_NTPData ntp_source_name;
  } data; /* Command specific parameters */

  /* Padding used to prevent traffic amplification.  It only defines the
@@ -442,7 +487,11 @@ typedef struct {
 #define RPY_SMOOTHING 13
 #define RPY_SERVER_STATS 14
 #define RPY_CLIENT_ACCESSES_BY_INDEX2 15
-#define N_REPLY_TYPES 16
+#define RPY_NTP_DATA 16
+#define RPY_MANUAL_TIMESTAMP2 17
+#define RPY_MANUAL_LIST2 18
+#define RPY_NTP_SOURCE_NAME 19
+#define N_REPLY_TYPES 20

 /* Status codes */
 #define STT_SUCCESS 0
@@ -466,6 +515,7 @@ typedef struct {
 #define STT_INVALIDAF 17
 #define STT_BADPKTVERSION 18
 #define STT_BADPKTLENGTH 19
+#define STT_INVALIDNAME 21

 typedef struct {
  int32_t EOR;
@@ -512,7 +562,7 @@ typedef struct {
  IPAddr ip_addr;
  uint16_t stratum;
  uint16_t leap_status;
-  Timeval ref_time;
+  Timespec ref_time;
  Float current_correction;
  Float last_offset;
  Float rms_offset;
@@ -540,7 +590,7 @@ typedef struct {
 } RPY_Sourcestats;

 typedef struct {
-  Timeval ref_time;
+  Timespec ref_time;
  uint16_t n_samples;
  uint16_t n_runs;
  uint32_t span_seconds;
@@ -550,7 +600,7 @@ typedef struct {
 } RPY_Rtc;

 typedef struct {
-  uint32_t centiseconds;
+  Float offset;
  Float dfreq_ppm;
  Float new_afreq_ppm;
  int32_t EOR;
@@ -590,7 +640,7 @@ typedef struct {
 #define MAX_MANUAL_LIST_SAMPLES 16

 typedef struct {
-  Timeval when;
+  Timespec when;
  Float slewed_offset;
  Float orig_offset;
  Float residual;
@@ -624,6 +674,44 @@ typedef struct {
  int32_t EOR;
 } RPY_Smoothing;

+#define RPY_NTP_FLAGS_TESTS 0x3ff
+#define RPY_NTP_FLAG_INTERLEAVED 0x4000
+#define RPY_NTP_FLAG_AUTHENTICATED 0x8000
+
+typedef struct {
+  IPAddr remote_addr;
+  IPAddr local_addr;
+  uint16_t remote_port;
+  uint8_t leap;
+  uint8_t version;
+  uint8_t mode;
+  uint8_t stratum;
+  int8_t poll;
+  int8_t precision;
+  Float root_delay;
+  Float root_dispersion;
+  uint32_t ref_id;
+  Timespec ref_time;
+  Float offset;
+  Float peer_delay;
+  Float peer_dispersion;
+  Float response_time;
+  Float jitter_asymmetry;
+  uint16_t flags;
+  uint8_t tx_tss_char;
+  uint8_t rx_tss_char;
+  uint32_t total_tx_count;
+  uint32_t total_rx_count;
+  uint32_t total_valid_count;
+  uint32_t reserved[4];
+  int32_t EOR;
+} RPY_NTPData;
+
+typedef struct {
+  int8_t name[256];
+  int32_t EOR;
+} RPY_NTPSourceName;
+
 typedef struct {
  uint8_t version;
  uint8_t pkt_type;
@@ -652,6 +740,8 @@ typedef struct {
    RPY_ManualList manual_list;
    RPY_Activity activity;
    RPY_Smoothing smoothing;
+    RPY_NTPData ntp_data;
+    RPY_NTPSourceName ntp_source_name;
  } data; /* Reply specific parameters */

 } CMD_Reply;
--- a/client.c
+++ b/client.c
--- a/clientlog.c
+++ b/clientlog.c
@@ -3,7 +3,7 @@

 **********************************************************************
 * Copyright (C) Richard P. Curnow  1997-2003
- * Copyright (C) Miroslav Lichvar  2009, 2015-2016
+ * Copyright (C) Miroslav Lichvar  2009, 2015-2017
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
@@ -39,6 +39,7 @@
 #include "clientlog.h"
 #include "conf.h"
 #include "memory.h"
+#include "ntp.h"
 #include "reports.h"
 #include "util.h"
 #include "logging.h"
@@ -57,6 +58,8 @@ typedef struct {
  int8_t cmd_rate;
  int8_t ntp_timeout_rate;
  uint8_t flags;
+  NTP_int64 ntp_rx_ts;
+  NTP_int64 ntp_tx_ts;
 } Record;

 /* Hash table of records, there is a fixed number of records per slot */
@@ -83,6 +86,10 @@ static unsigned int max_slots;
 #define TS_FRAC 4
 #define INVALID_TS 0

+/* Static offset included in conversion to the fixed-point timestamps to
+   randomise their alignment */
+static uint32_t ts_offset;
+
 /* Request rates are saved in the record as 8-bit scaled log2 values */
 #define RATE_SCALE 4
 #define MIN_RATE (-14 * RATE_SCALE)
@@ -92,7 +99,7 @@ static unsigned int max_slots;
   number of tokens spent on response are determined from configured
   minimum inverval between responses (in log2) and burst length. */

-#define MIN_LIMIT_INTERVAL (-TS_FRAC)
+#define MIN_LIMIT_INTERVAL (-15 - TS_FRAC)
 #define MAX_LIMIT_INTERVAL 12
 #define MIN_LIMIT_BURST 1
 #define MAX_LIMIT_BURST 255
@@ -102,7 +109,8 @@ static uint16_t max_cmd_tokens;
 static uint16_t ntp_tokens_per_packet;
 static uint16_t cmd_tokens_per_packet;

-/* Reduction of token rates to avoid overflow of 16-bit counters */
+/* Reduction of token rates to avoid overflow of 16-bit counters.  Negative
+   shift is used for coarse limiting with intervals shorter than -TS_FRAC. */
 static int ntp_token_shift;
 static int cmd_token_shift;

@@ -120,6 +128,9 @@ static int cmd_leak_rate;
 /* Flag indicating whether the last response was dropped */
 #define FLAG_NTP_DROPPED 0x1

+/* NTP limit interval in log2 */
+static int ntp_limit_interval;
+
 /* Flag indicating whether facility is turned on or not */
 static int active;

@@ -130,6 +141,8 @@ static uint32_t total_ntp_drops;
 static uint32_t total_cmd_drops;
 static uint32_t total_record_drops;

+#define NSEC_PER_SEC 1000000000U
+
 /* ================================================== */

 static int expand_hashtable(void);
@@ -155,7 +168,7 @@ get_record(IPAddr *ip)
  time_t last_hit, oldest_hit = 0;
  Record *record, *oldest_record;

-  if (ip->family != IPADDR_INET4 && ip->family != IPADDR_INET6)
+  if (!active || (ip->family != IPADDR_INET4 && ip->family != IPADDR_INET6))
    return NULL;

  while (1) {
@@ -206,6 +219,8 @@ get_record(IPAddr *ip)
  record->ntp_rate = record->cmd_rate = INVALID_RATE;
  record->ntp_timeout_rate = INVALID_RATE;
  record->flags = 0;
+  UTI_ZeroNtp64(&record->ntp_rx_ts);
+  UTI_ZeroNtp64(&record->ntp_tx_ts);

  return record;
 }
@@ -266,16 +281,23 @@ set_bucket_params(int interval, int burst, uint16_t *max_tokens,
  interval = CLAMP(MIN_LIMIT_INTERVAL, interval, MAX_LIMIT_INTERVAL);
  burst = CLAMP(MIN_LIMIT_BURST, burst, MAX_LIMIT_BURST);

-  /* Find smallest shift with which the maximum number fits in 16 bits */
-  for (*token_shift = 0; *token_shift < interval + TS_FRAC; (*token_shift)++) {
-    if (burst << (TS_FRAC + interval - *token_shift) < 1U << 16)
-      break;
+  if (interval >= -TS_FRAC) {
+    /* Find the smallest shift with which the maximum number fits in 16 bits */
+    for (*token_shift = 0; *token_shift < interval + TS_FRAC; (*token_shift)++) {
+      if (burst << (TS_FRAC + interval - *token_shift) < 1U << 16)
+        break;
+    }
+  } else {
+    /* Coarse rate limiting */
+    *token_shift = interval + TS_FRAC;
+    *tokens_per_packet = 1;
+    burst = MAX(1U << -*token_shift, burst);
  }

  *tokens_per_packet = 1U << (TS_FRAC + interval - *token_shift);
  *max_tokens = *tokens_per_packet * burst;

-  DEBUG_LOG(LOGF_ClientLog, "Tokens max %d packet %d shift %d",
+  DEBUG_LOG("Tokens max %d packet %d shift %d",
            *max_tokens, *tokens_per_packet, *token_shift);
 }

@@ -290,11 +312,13 @@ CLG_Initialise(void)
  ntp_tokens_per_packet = cmd_tokens_per_packet = 0;
  ntp_token_shift = cmd_token_shift = 0;
  ntp_leak_rate = cmd_leak_rate = 0;
+  ntp_limit_interval = MIN_LIMIT_INTERVAL;

  if (CNF_GetNTPRateLimit(&interval, &burst, &leak_rate)) {
    set_bucket_params(interval, burst, &max_ntp_tokens, &ntp_tokens_per_packet,
                      &ntp_token_shift);
    ntp_leak_rate = CLAMP(MIN_LEAK_RATE, leak_rate, MAX_LEAK_RATE);
+    ntp_limit_interval = CLAMP(MIN_LIMIT_INTERVAL, interval, MAX_LIMIT_INTERVAL);
  }

  if (CNF_GetCommandRateLimit(&interval, &burst, &leak_rate)) {
@@ -306,7 +330,7 @@ CLG_Initialise(void)
  active = !CNF_GetNoClientLog();
  if (!active) {
    if (ntp_leak_rate || cmd_leak_rate)
-      LOG_FATAL(LOGF_ClientLog, "ratelimit cannot be used with noclientlog");
+      LOG_FATAL("ratelimit cannot be used with noclientlog");
    return;
  }

@@ -320,6 +344,9 @@ CLG_Initialise(void)
  records = NULL;

  expand_hashtable();
+
+  UTI_GetRandomBytes(&ts_offset, sizeof (ts_offset));
+  ts_offset %= NSEC_PER_SEC / (1U << TS_FRAC);
 }

 /* ================================================== */
@@ -336,23 +363,30 @@ CLG_Finalise(void)
 /* ================================================== */

 static uint32_t
-get_ts_from_timeval(struct timeval *tv)
+get_ts_from_timespec(struct timespec *ts)
 {
-  uint32_t sec = tv->tv_sec, usec = tv->tv_usec;
+  uint32_t sec = ts->tv_sec, nsec = ts->tv_nsec;

-  return sec << TS_FRAC | (4295U * usec - (usec >> 5)) >> (32 - TS_FRAC);
+  nsec += ts_offset;
+  if (nsec >= NSEC_PER_SEC) {
+    nsec -= NSEC_PER_SEC;
+    sec++;
+  }
+
+  /* This is fast and accurate enough */
+  return sec << TS_FRAC | (140740U * (nsec >> 15)) >> (32 - TS_FRAC);
 }

 /* ================================================== */

 static void
-update_record(struct timeval *now, uint32_t *last_hit, uint32_t *hits,
+update_record(struct timespec *now, uint32_t *last_hit, uint32_t *hits,
              uint16_t *tokens, uint32_t max_tokens, int token_shift, int8_t *rate)
 {
  uint32_t interval, now_ts, prev_hit, new_tokens;
  int interval2;

-  now_ts = get_ts_from_timeval(now);
+  now_ts = get_ts_from_timespec(now);

  prev_hit = *last_hit;
  *last_hit = now_ts;
@@ -363,7 +397,12 @@ update_record(struct timeval *now, uint32_t *last_hit, uint32_t *hits,
  if (prev_hit == INVALID_TS || (int32_t)interval < 0)
    return;

-  new_tokens = (now_ts >> token_shift) - (prev_hit >> token_shift);
+  if (token_shift >= 0)
+    new_tokens = (now_ts >> token_shift) - (prev_hit >> token_shift);
+  else if (now_ts - prev_hit > max_tokens)
+    new_tokens = max_tokens;
+  else
+    new_tokens = (now_ts - prev_hit) << -token_shift;
  *tokens = MIN(*tokens + new_tokens, max_tokens);

  /* Convert the interval to scaled and rounded log2 */
@@ -405,15 +444,26 @@ get_index(Record *record)
 /* ================================================== */

 int
-CLG_LogNTPAccess(IPAddr *client, struct timeval *now)
+CLG_GetClientIndex(IPAddr *client)
+{
+  Record *record;
+
+  record = get_record(client);
+  if (record == NULL)
+    return -1;
+
+  return get_index(record);
+}
+
+/* ================================================== */
+
+int
+CLG_LogNTPAccess(IPAddr *client, struct timespec *now)
 {
  Record *record;

  total_ntp_hits++;

-  if (!active)
-    return -1;
-
  record = get_record(client);
  if (record == NULL)
    return -1;
@@ -425,7 +475,7 @@ CLG_LogNTPAccess(IPAddr *client, struct timeval *now)
                record->flags & FLAG_NTP_DROPPED ?
                &record->ntp_timeout_rate : &record->ntp_rate);

-  DEBUG_LOG(LOGF_ClientLog, "NTP hits %"PRIu32" rate %d trate %d tokens %d",
+  DEBUG_LOG("NTP hits %"PRIu32" rate %d trate %d tokens %d",
            record->ntp_hits, record->ntp_rate, record->ntp_timeout_rate,
            record->ntp_tokens);

@@ -435,15 +485,12 @@ CLG_LogNTPAccess(IPAddr *client, struct timeval *now)
 /* ================================================== */

 int
-CLG_LogCommandAccess(IPAddr *client, struct timeval *now)
+CLG_LogCommandAccess(IPAddr *client, struct timespec *now)
 {
  Record *record;

  total_cmd_hits++;

-  if (!active)
-    return -1;
-
  record = get_record(client);
  if (record == NULL)
    return -1;
@@ -452,7 +499,7 @@ CLG_LogCommandAccess(IPAddr *client, struct timeval *now)
                &record->cmd_tokens, max_cmd_tokens, cmd_token_shift,
                &record->cmd_rate);

-  DEBUG_LOG(LOGF_ClientLog, "Cmd hits %"PRIu32" rate %d tokens %d",
+  DEBUG_LOG("Cmd hits %"PRIu32" rate %d tokens %d",
            record->cmd_hits, record->cmd_rate, record->cmd_tokens);

  return get_index(record);
@@ -552,7 +599,27 @@ CLG_LimitCommandResponseRate(int index)

 /* ================================================== */

-extern int
+void CLG_GetNtpTimestamps(int index, NTP_int64 **rx_ts, NTP_int64 **tx_ts)
+{
+  Record *record;
+
+  record = ARR_GetElement(records, index);
+
+  *rx_ts = &record->ntp_rx_ts;
+  *tx_ts = &record->ntp_tx_ts;
+}
+
+/* ================================================== */
+
+int
+CLG_GetNtpMinPoll(void)
+{
+  return ntp_limit_interval;
+}
+
+/* ================================================== */
+
+int
 CLG_GetNumberOfIndices(void)
 {
  if (!active)
@@ -586,7 +653,7 @@ static uint32_t get_last_ago(uint32_t x, uint32_t y)
 /* ================================================== */

 int
-CLG_GetClientAccessReportByIndex(int index, RPT_ClientAccessByIndex_Report *report, struct timeval *now)
+CLG_GetClientAccessReportByIndex(int index, RPT_ClientAccessByIndex_Report *report, struct timespec *now)
 {
  Record *record;
  uint32_t now_ts;
@@ -599,7 +666,7 @@ CLG_GetClientAccessReportByIndex(int index, RPT_ClientAccessByIndex_Report *repo
  if (record->ip_addr.family == IPADDR_UNSPEC)
    return 0;

-  now_ts = get_ts_from_timeval(now);
+  now_ts = get_ts_from_timespec(now);

  report->ip_addr = record->ip_addr;
  report->ntp_hits = record->ntp_hits;
--- a/clientlog.h
+++ b/clientlog.h
@@ -33,15 +33,18 @@

 extern void CLG_Initialise(void);
 extern void CLG_Finalise(void);
-extern int CLG_LogNTPAccess(IPAddr *client, struct timeval *now);
-extern int CLG_LogCommandAccess(IPAddr *client, struct timeval *now);
+extern int CLG_GetClientIndex(IPAddr *client);
+extern int CLG_LogNTPAccess(IPAddr *client, struct timespec *now);
+extern int CLG_LogCommandAccess(IPAddr *client, struct timespec *now);
 extern int CLG_LimitNTPResponseRate(int index);
 extern int CLG_LimitCommandResponseRate(int index);
+extern void CLG_GetNtpTimestamps(int index, NTP_int64 **rx_ts, NTP_int64 **tx_ts);
+extern int CLG_GetNtpMinPoll(void);

 /* And some reporting functions, for use by chronyc. */

 extern int CLG_GetNumberOfIndices(void);
-extern int CLG_GetClientAccessReportByIndex(int index, RPT_ClientAccessByIndex_Report *report, struct timeval *now);
+extern int CLG_GetClientAccessReportByIndex(int index, RPT_ClientAccessByIndex_Report *report, struct timespec *now);
 extern void CLG_GetServerStatsReport(RPT_ServerStatsReport *report);

 #endif /* GOT_CLIENTLOG_H */
--- a/cmac.h
+++ b/cmac.h
@@ -0,0 +1,41 @@
+/*
+  chronyd/chronyc - Programs for keeping computer clocks accurate.
+
+ **********************************************************************
+ * Copyright (C) Miroslav Lichvar  2019
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ * 
+ **********************************************************************
+
+  =======================================================================
+
+  Header file for CMAC.
+
+  */
+
+#ifndef GOT_CMAC_H
+#define GOT_CMAC_H
+
+typedef struct CMC_Instance_Record *CMC_Instance;
+
+extern unsigned int CMC_GetKeyLength(const char *cipher);
+extern CMC_Instance CMC_CreateInstance(const char *cipher, const unsigned char *key,
+                                       unsigned int length);
+extern unsigned int CMC_Hash(CMC_Instance inst, const unsigned char *in, unsigned int in_len,
+                             unsigned char *out, unsigned int out_len);
+extern void CMC_DestroyInstance(CMC_Instance inst);
+
+#endif
+
--- a/cmac_nettle.c
+++ b/cmac_nettle.c
@@ -0,0 +1,115 @@
+/*
+  chronyd/chronyc - Programs for keeping computer clocks accurate.
+
+ **********************************************************************
+ * Copyright (C) Miroslav Lichvar  2019
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ * 
+ **********************************************************************
+
+  =======================================================================
+
+  Support for AES128 and AES256 CMAC in Nettle.
+
+  */
+
+#include "config.h"
+
+#include "sysincl.h"
+
+#include <nettle/cmac.h>
+
+#include "cmac.h"
+#include "memory.h"
+
+struct CMC_Instance_Record {
+  int key_length;
+  union {
+    struct cmac_aes128_ctx aes128;
+    struct cmac_aes256_ctx aes256;
+  } context;
+};
+
+/* ================================================== */
+
+unsigned int
+CMC_GetKeyLength(const char *cipher)
+{
+  if (strcmp(cipher, "AES128") == 0)
+    return AES128_KEY_SIZE;
+  else if (strcmp(cipher, "AES256") == 0)
+    return AES256_KEY_SIZE;
+  return 0;
+}
+
+/* ================================================== */
+
+CMC_Instance
+CMC_CreateInstance(const char *cipher, const unsigned char *key, unsigned int length)
+{
+  CMC_Instance inst;
+
+  if (length == 0 || length != CMC_GetKeyLength(cipher))
+    return NULL;
+
+  inst = MallocNew(struct CMC_Instance_Record);
+  inst->key_length = length;
+
+  switch (length) {
+    case AES128_KEY_SIZE:
+      cmac_aes128_set_key(&inst->context.aes128, key);
+      break;
+    case AES256_KEY_SIZE:
+      cmac_aes256_set_key(&inst->context.aes256, key);
+      break;
+    default:
+      assert(0);
+  }
+
+  return inst;
+}
+
+/* ================================================== */
+
+unsigned int
+CMC_Hash(CMC_Instance inst, const unsigned char *in, unsigned int in_len,
+         unsigned char *out, unsigned int out_len)
+{
+  if (out_len > CMAC128_DIGEST_SIZE)
+    out_len = CMAC128_DIGEST_SIZE;
+
+  switch (inst->key_length) {
+    case AES128_KEY_SIZE:
+      cmac_aes128_update(&inst->context.aes128, in_len, in);
+      cmac_aes128_digest(&inst->context.aes128, out_len, out);
+      break;
+    case AES256_KEY_SIZE:
+      cmac_aes256_update(&inst->context.aes256, in_len, in);
+      cmac_aes256_digest(&inst->context.aes256, out_len, out);
+      break;
+    default:
+      assert(0);
+  }
+
+  return out_len;
+}
+
+/* ================================================== */
+
+void
+CMC_DestroyInstance(CMC_Instance inst)
+{
+  Free(inst);
+}
--- a/cmdmon.c
+++ b/cmdmon.c
@@ -3,7 +3,7 @@

 **********************************************************************
 * Copyright (C) Richard P. Curnow  1997-2003
- * Copyright (C) Miroslav Lichvar  2009-2016
+ * Copyright (C) Miroslav Lichvar  2009-2016, 2018
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
@@ -38,6 +38,7 @@
 #include "ntp_sources.h"
 #include "ntp_core.h"
 #include "smooth.h"
+#include "socket.h"
 #include "sources.h"
 #include "sourcestats.h"
 #include "reference.h"
@@ -53,21 +54,12 @@

 /* ================================================== */

-union sockaddr_all {
-  struct sockaddr_in in4;
-#ifdef FEAT_IPV6
-  struct sockaddr_in6 in6;
-#endif
-  struct sockaddr_un un;
-  struct sockaddr sa;
-};
+#define INVALID_SOCK_FD (-5)

 /* File descriptors for command and monitoring sockets */
 static int sock_fdu;
 static int sock_fd4;
-#ifdef FEAT_IPV6
 static int sock_fd6;
-#endif

 /* Flag indicating whether this module has been initialised or not */
 static int initialised = 0;
@@ -133,6 +125,16 @@ static const char permissions[] = {
  PERMIT_AUTH, /* SERVER_STATS */
  PERMIT_AUTH, /* CLIENT_ACCESSES_BY_INDEX2 */
  PERMIT_AUTH, /* LOCAL2 */
+  PERMIT_AUTH, /* NTP_DATA */
+  PERMIT_AUTH, /* ADD_SERVER2 */
+  PERMIT_AUTH, /* ADD_PEER2 */
+  PERMIT_AUTH, /* ADD_SERVER3 */
+  PERMIT_AUTH, /* ADD_PEER3 */
+  PERMIT_AUTH, /* SHUTDOWN */
+  PERMIT_AUTH, /* ONOFFLINE */
+  PERMIT_AUTH, /* ADD_SOURCE */
+  PERMIT_OPEN, /* NTP_SOURCE_NAME */
+  PERMIT_AUTH, /* RESET */
 };

 /* ================================================== */
@@ -143,106 +145,53 @@ static ADF_AuthTable access_auth_table;

 /* ================================================== */
 /* Forward prototypes */
-static void read_from_cmd_socket(void *anything);
+static void read_from_cmd_socket(int sock_fd, int event, void *anything);

 /* ================================================== */

 static int
-prepare_socket(int family, int port_number)
+open_socket(int family)
 {
-  int sock_fd;
-  socklen_t my_addr_len;
-  union sockaddr_all my_addr;
-  IPAddr bind_address;
-  int on_off = 1;
-
-  sock_fd = socket(family, SOCK_DGRAM, 0);
-  if (sock_fd < 0) {
-    LOG(LOGS_ERR, LOGF_CmdMon, "Could not open %s command socket : %s",
-        UTI_SockaddrFamilyToString(family), strerror(errno));
-    return -1;
-  }
-
-  /* Close on exec */
-  UTI_FdSetCloexec(sock_fd);
-
-  if (family != AF_UNIX) {
-    /* Allow reuse of port number */
-    if (setsockopt(sock_fd, SOL_SOCKET, SO_REUSEADDR, (char *) &on_off, sizeof(on_off)) < 0) {
-      LOG(LOGS_ERR, LOGF_CmdMon, "Could not set reuseaddr socket options");
-      /* Don't quit - we might survive anyway */
-    }
-
-#ifdef IP_FREEBIND
-    /* Allow binding to address that doesn't exist yet */
-    if (setsockopt(sock_fd, IPPROTO_IP, IP_FREEBIND, (char *)&on_off, sizeof(on_off)) < 0) {
-      LOG(LOGS_ERR, LOGF_CmdMon, "Could not set free bind socket option");
-    }
-#endif
-
-#ifdef FEAT_IPV6
-    if (family == AF_INET6) {
-#ifdef IPV6_V6ONLY
-      /* Receive IPv6 packets only */
-      if (setsockopt(sock_fd, IPPROTO_IPV6, IPV6_V6ONLY, (char *)&on_off, sizeof(on_off)) < 0) {
-        LOG(LOGS_ERR, LOGF_CmdMon, "Could not request IPV6_V6ONLY socket option");
-      }
-#endif
-    }
-#endif
-  }
-
-  memset(&my_addr, 0, sizeof (my_addr));
+  IPSockAddr local_addr;
+  const char *local_path;
+  int sock_fd, port;

  switch (family) {
-    case AF_INET:
-      my_addr_len = sizeof (my_addr.in4);
-      my_addr.in4.sin_family = family;
-      my_addr.in4.sin_port = htons((unsigned short)port_number);
+    case IPADDR_INET4:
+    case IPADDR_INET6:
+      port = CNF_GetCommandPort();
+      if (port == 0 || !SCK_IsFamilySupported(family))
+        return INVALID_SOCK_FD;

-      CNF_GetBindCommandAddress(IPADDR_INET4, &bind_address);
+      CNF_GetBindCommandAddress(family, &local_addr.ip_addr);
+      if (local_addr.ip_addr.family != family)
+        SCK_GetLoopbackIPAddress(family, &local_addr.ip_addr);
+      local_addr.port = port;
+
+      sock_fd = SCK_OpenUdpSocket(NULL, &local_addr, SCK_FLAG_RX_DEST_ADDR);
+      if (sock_fd < 0) {
+        LOG(LOGS_ERR, "Could not open command socket on %s",
+            UTI_IPSockAddrToString(&local_addr));
+        return INVALID_SOCK_FD;
+      }

-      if (bind_address.family == IPADDR_INET4)
-        my_addr.in4.sin_addr.s_addr = htonl(bind_address.addr.in4);
-      else
-        my_addr.in4.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
      break;
-#ifdef FEAT_IPV6
-    case AF_INET6:
-      my_addr_len = sizeof (my_addr.in6);
-      my_addr.in6.sin6_family = family;
-      my_addr.in6.sin6_port = htons((unsigned short)port_number);
+    case IPADDR_UNSPEC:
+      local_path = CNF_GetBindCommandPath();

-      CNF_GetBindCommandAddress(IPADDR_INET6, &bind_address);
+      sock_fd = SCK_OpenUnixDatagramSocket(NULL, local_path, 0);
+      if (sock_fd < 0) {
+        LOG(LOGS_ERR, "Could not open command socket on %s", local_path);
+        return INVALID_SOCK_FD;
+      }

-      if (bind_address.family == IPADDR_INET6)
-        memcpy(my_addr.in6.sin6_addr.s6_addr, bind_address.addr.in6,
-            sizeof (my_addr.in6.sin6_addr.s6_addr));
-      else
-        my_addr.in6.sin6_addr = in6addr_loopback;
-      break;
-#endif
-    case AF_UNIX:
-      my_addr_len = sizeof (my_addr.un);
-      my_addr.un.sun_family = family;
-      if (snprintf(my_addr.un.sun_path, sizeof (my_addr.un.sun_path), "%s",
-                   CNF_GetBindCommandPath()) >= sizeof (my_addr.un.sun_path))
-        LOG_FATAL(LOGF_CmdMon, "Unix socket path too long");
-      unlink(my_addr.un.sun_path);
      break;
    default:
      assert(0);
  }

-  if (bind(sock_fd, &my_addr.sa, my_addr_len) < 0) {
-    LOG(LOGS_ERR, LOGF_CmdMon, "Could not bind %s command socket : %s",
-        UTI_SockaddrFamilyToString(family), strerror(errno));
-    close(sock_fd);
-    return -1;
-  }
-
  /* Register handler for read events on the socket */
-  SCH_AddInputFileHandler(sock_fd, read_from_cmd_socket, (void *)(long)sock_fd);
+  SCH_AddFileHandler(sock_fd, SCH_FILE_INPUT, read_from_cmd_socket, NULL);

  return sock_fd;
 }
@@ -273,7 +222,6 @@ do_size_checks(void)
  for (i = 1; i < N_REPLY_TYPES; i++) {
    reply.reply = htons(i);
    reply.status = STT_SUCCESS;
-    reply.data.manual_list.n_samples = htonl(MAX_MANUAL_LIST_SAMPLES);
    reply_length = PKL_ReplyLength(&reply);
    if ((reply_length && reply_length < offsetof(CMD_Reply, data)) ||
        reply_length > sizeof (CMD_Reply))
@@ -286,37 +234,22 @@ do_size_checks(void)
 void
 CAM_Initialise(int family)
 {
-  int port_number;
-
  assert(!initialised);
  assert(sizeof (permissions) / sizeof (permissions[0]) == N_REQUEST_TYPES);
  do_size_checks();

  initialised = 1;
-  sock_fdu = -1;
-  port_number = CNF_GetCommandPort();
+  sock_fdu = INVALID_SOCK_FD;
+  sock_fd4 = INVALID_SOCK_FD;
+  sock_fd6 = INVALID_SOCK_FD;

-  if (port_number && (family == IPADDR_UNSPEC || family == IPADDR_INET4))
-    sock_fd4 = prepare_socket(AF_INET, port_number);
-  else
-    sock_fd4 = -1;
-#ifdef FEAT_IPV6
-  if (port_number && (family == IPADDR_UNSPEC || family == IPADDR_INET6))
-    sock_fd6 = prepare_socket(AF_INET6, port_number);
-  else
-    sock_fd6 = -1;
-#endif
+  if (family == IPADDR_UNSPEC || family == IPADDR_INET4)
+    sock_fd4 = open_socket(IPADDR_INET4);

-  if (port_number && sock_fd4 < 0
-#ifdef FEAT_IPV6
-      && sock_fd6 < 0
-#endif
-      ) {
-    LOG_FATAL(LOGF_CmdMon, "Could not open any command socket");
-  }
+  if (family == IPADDR_UNSPEC || family == IPADDR_INET6)
+    sock_fd6 = open_socket(IPADDR_INET6);

  access_auth_table = ADF_CreateTable();
-
 }

 /* ================================================== */
@@ -324,24 +257,24 @@ CAM_Initialise(int family)
 void
 CAM_Finalise(void)
 {
-  if (sock_fdu >= 0) {
-    SCH_RemoveInputFileHandler(sock_fdu);
-    close(sock_fdu);
-    unlink(CNF_GetBindCommandPath());
+  if (sock_fdu != INVALID_SOCK_FD) {
+    SCH_RemoveFileHandler(sock_fdu);
+    SCK_RemoveSocket(sock_fdu);
+    SCK_CloseSocket(sock_fdu);
+    sock_fdu = INVALID_SOCK_FD;
  }
-  sock_fdu = -1;
-  if (sock_fd4 >= 0) {
-    SCH_RemoveInputFileHandler(sock_fd4);
-    close(sock_fd4);
+
+  if (sock_fd4 != INVALID_SOCK_FD) {
+    SCH_RemoveFileHandler(sock_fd4);
+    SCK_CloseSocket(sock_fd4);
+    sock_fd4 = INVALID_SOCK_FD;
  }
-  sock_fd4 = -1;
-#ifdef FEAT_IPV6
-  if (sock_fd6 >= 0) {
-    SCH_RemoveInputFileHandler(sock_fd6);
-    close(sock_fd6);
+
+  if (sock_fd6 != INVALID_SOCK_FD) {
+    SCH_RemoveFileHandler(sock_fd6);
+    SCK_CloseSocket(sock_fd6);
+    sock_fd6 = INVALID_SOCK_FD;
  }
-  sock_fd6 = -1;
-#endif

  ADF_DestroyTable(access_auth_table);

@@ -356,50 +289,18 @@ CAM_OpenUnixSocket(void)
  /* This is separated from CAM_Initialise() as it needs to be called when
     the process has already dropped the root privileges */
  if (CNF_GetBindCommandPath()[0])
-    sock_fdu = prepare_socket(AF_UNIX, 0);
+    sock_fdu = open_socket(IPADDR_UNSPEC);
 }

 /* ================================================== */

 static void
-transmit_reply(CMD_Reply *msg, union sockaddr_all *where_to)
+transmit_reply(int sock_fd, SCK_Message *message)
 {
-  int status;
-  int tx_message_length;
-  int sock_fd;
-  socklen_t addrlen;
+  message->length = PKL_ReplyLength((CMD_Reply *)message->data);

-  switch (where_to->sa.sa_family) {
-    case AF_INET:
-      sock_fd = sock_fd4;
-      addrlen = sizeof (where_to->in4);
-      break;
-#ifdef FEAT_IPV6
-    case AF_INET6:
-      sock_fd = sock_fd6;
-      addrlen = sizeof (where_to->in6);
-      break;
-#endif
-    case AF_UNIX:
-      sock_fd = sock_fdu;
-      addrlen = sizeof (where_to->un);
-      break;
-    default:
-      assert(0);
-  }
-
-  tx_message_length = PKL_ReplyLength(msg);
-  status = sendto(sock_fd, (void *) msg, tx_message_length, 0,
-                  &where_to->sa, addrlen);
-
-  if (status < 0) {
-    DEBUG_LOG(LOGF_CmdMon, "Could not send to %s fd %d : %s",
-              UTI_SockaddrToString(&where_to->sa), sock_fd, strerror(errno));
+  if (!SCK_SendMessage(sock_fd, message, 0))
    return;
-  }
-
-  DEBUG_LOG(LOGF_CmdMon, "Sent %d bytes to %s fd %d", status,
-            UTI_SockaddrToString(&where_to->sa), sock_fd);
 }
  
 /* ================================================== */
@@ -419,7 +320,7 @@ handle_online(CMD_Request *rx_message, CMD_Reply *tx_message)

  UTI_IPNetworkToHost(&rx_message->data.online.mask, &mask);
  UTI_IPNetworkToHost(&rx_message->data.online.address, &address);
-  if (!NSR_TakeSourcesOnline(&mask, &address))
+  if (!NSR_SetConnectivity(&mask, &address, SRC_ONLINE))
    tx_message->status = htons(STT_NOSUCHSOURCE);
 }

@@ -432,12 +333,24 @@ handle_offline(CMD_Request *rx_message, CMD_Reply *tx_message)

  UTI_IPNetworkToHost(&rx_message->data.offline.mask, &mask);
  UTI_IPNetworkToHost(&rx_message->data.offline.address, &address);
-  if (!NSR_TakeSourcesOffline(&mask, &address))
+  if (!NSR_SetConnectivity(&mask, &address, SRC_OFFLINE))
    tx_message->status = htons(STT_NOSUCHSOURCE);
 }

 /* ================================================== */

+static void
+handle_onoffline(CMD_Request *rx_message, CMD_Reply *tx_message)
+{
+  IPAddr address, mask;
+
+  address.family = mask.family = IPADDR_UNSPEC;
+  if (!NSR_SetConnectivity(&mask, &address, SRC_MAYBE_ONLINE))
+    ;
+}
+
+/* ================================================== */
+
 static void
 handle_burst(CMD_Request *rx_message, CMD_Reply *tx_message)
 {
@@ -564,15 +477,14 @@ handle_modify_makestep(CMD_Request *rx_message, CMD_Reply *tx_message)
 static void
 handle_settime(CMD_Request *rx_message, CMD_Reply *tx_message)
 {
-  struct timeval ts;
-  long offset_cs;
-  double dfreq_ppm, new_afreq_ppm;
-  UTI_TimevalNetworkToHost(&rx_message->data.settime.ts, &ts);
+  struct timespec ts;
+  double offset, dfreq_ppm, new_afreq_ppm;
+  UTI_TimespecNetworkToHost(&rx_message->data.settime.ts, &ts);
  if (!MNL_IsEnabled()) {
    tx_message->status = htons(STT_NOTENABLED);
-  } else if (MNL_AcceptTimestamp(&ts, &offset_cs, &dfreq_ppm, &new_afreq_ppm)) {
-    tx_message->reply = htons(RPY_MANUAL_TIMESTAMP);
-    tx_message->data.manual_timestamp.centiseconds = htonl((int32_t)offset_cs);
+  } else if (MNL_AcceptTimestamp(&ts, &offset, &dfreq_ppm, &new_afreq_ppm)) {
+    tx_message->reply = htons(RPY_MANUAL_TIMESTAMP2);
+    tx_message->data.manual_timestamp.offset = UTI_FloatHostToNetwork(offset);
    tx_message->data.manual_timestamp.dfreq_ppm = UTI_FloatHostToNetwork(dfreq_ppm);
    tx_message->data.manual_timestamp.new_afreq_ppm = UTI_FloatHostToNetwork(new_afreq_ppm);
  } else {
@@ -634,7 +546,7 @@ static void
 handle_source_data(CMD_Request *rx_message, CMD_Reply *tx_message)
 {
  RPT_SourceReport report;
-  struct timeval now_corr;
+  struct timespec now_corr;

  /* Get data */
  SCH_GetLastEventTime(&now_corr, NULL, NULL);
@@ -766,51 +678,93 @@ handle_cmdaccheck(CMD_Request *rx_message, CMD_Reply *tx_message)
 /* ================================================== */

 static void
-handle_add_source(NTP_Source_Type type, CMD_Request *rx_message, CMD_Reply *tx_message)
+handle_add_source(CMD_Request *rx_message, CMD_Reply *tx_message)
 {
-  NTP_Remote_Address rem_addr;
+  NTP_Source_Type type;
  SourceParameters params;
  NSR_Status status;
+  char *name;
+  int pool, port;
  
-  UTI_IPNetworkToHost(&rx_message->data.ntp_source.ip_addr, &rem_addr.ip_addr);
-  rem_addr.port = (unsigned short)(ntohl(rx_message->data.ntp_source.port));
+  switch (ntohl(rx_message->data.ntp_source.type)) {
+    case REQ_ADDSRC_SERVER:
+      type = NTP_SERVER;
+      pool = 0;
+      break;
+    case REQ_ADDSRC_PEER:
+      type = NTP_PEER;
+      pool = 0;
+      break;
+    case REQ_ADDSRC_POOL:
+      type = NTP_SERVER;
+      pool = 1;
+      break;
+    default:
+      tx_message->status = htons(STT_INVALID);
+      return;
+  }
+
+  name = (char *)rx_message->data.ntp_source.name;
+
+  /* Make sure the name is terminated */
+  if (name[sizeof (rx_message->data.ntp_source.name) - 1] != '\0') {
+      tx_message->status = htons(STT_INVALIDNAME);
+      return;
+  }
+
+  port = (unsigned short)(ntohl(rx_message->data.ntp_source.port));
  params.minpoll = ntohl(rx_message->data.ntp_source.minpoll);
  params.maxpoll = ntohl(rx_message->data.ntp_source.maxpoll);
  params.presend_minpoll = ntohl(rx_message->data.ntp_source.presend_minpoll);
+  params.min_stratum = ntohl(rx_message->data.ntp_source.min_stratum);
+  params.poll_target = ntohl(rx_message->data.ntp_source.poll_target);
+  params.version = ntohl(rx_message->data.ntp_source.version);
+  params.max_sources = ntohl(rx_message->data.ntp_source.max_sources);
+  params.min_samples = ntohl(rx_message->data.ntp_source.min_samples);
+  params.max_samples = ntohl(rx_message->data.ntp_source.max_samples);
+  params.filter_length = ntohl(rx_message->data.ntp_source.filter_length);
  params.authkey = ntohl(rx_message->data.ntp_source.authkey);
-  params.online  = ntohl(rx_message->data.ntp_source.flags) & REQ_ADDSRC_ONLINE ? 1 : 0;
+  params.nts_port = ntohl(rx_message->data.ntp_source.nts_port);
+  params.max_delay = UTI_FloatNetworkToHost(rx_message->data.ntp_source.max_delay);
+  params.max_delay_ratio =
+    UTI_FloatNetworkToHost(rx_message->data.ntp_source.max_delay_ratio);
+  params.max_delay_dev_ratio =
+    UTI_FloatNetworkToHost(rx_message->data.ntp_source.max_delay_dev_ratio);
+  params.min_delay = UTI_FloatNetworkToHost(rx_message->data.ntp_source.min_delay);
+  params.asymmetry = UTI_FloatNetworkToHost(rx_message->data.ntp_source.asymmetry);
+  params.offset = UTI_FloatNetworkToHost(rx_message->data.ntp_source.offset);
+
+  params.connectivity = ntohl(rx_message->data.ntp_source.flags) & REQ_ADDSRC_ONLINE ?
+                        SRC_ONLINE : SRC_OFFLINE;
  params.auto_offline = ntohl(rx_message->data.ntp_source.flags) & REQ_ADDSRC_AUTOOFFLINE ? 1 : 0;
  params.iburst = ntohl(rx_message->data.ntp_source.flags) & REQ_ADDSRC_IBURST ? 1 : 0;
+  params.interleaved = ntohl(rx_message->data.ntp_source.flags) & REQ_ADDSRC_INTERLEAVED ? 1 : 0;
+  params.burst = ntohl(rx_message->data.ntp_source.flags) & REQ_ADDSRC_BURST ? 1 : 0;
+  params.nts = ntohl(rx_message->data.ntp_source.flags) & REQ_ADDSRC_NTS ? 1 : 0;
  params.sel_options =
    (ntohl(rx_message->data.ntp_source.flags) & REQ_ADDSRC_PREFER ? SRC_SELECT_PREFER : 0) |
    (ntohl(rx_message->data.ntp_source.flags) & REQ_ADDSRC_NOSELECT ? SRC_SELECT_NOSELECT : 0) |
    (ntohl(rx_message->data.ntp_source.flags) & REQ_ADDSRC_TRUST ? SRC_SELECT_TRUST : 0) |
    (ntohl(rx_message->data.ntp_source.flags) & REQ_ADDSRC_REQUIRE ? SRC_SELECT_REQUIRE : 0);
-  params.max_delay = UTI_FloatNetworkToHost(rx_message->data.ntp_source.max_delay);
-  params.max_delay_ratio = UTI_FloatNetworkToHost(rx_message->data.ntp_source.max_delay_ratio);

- /* not transmitted in cmdmon protocol yet */
-  params.min_stratum = SRC_DEFAULT_MINSTRATUM;       
-  params.poll_target = SRC_DEFAULT_POLLTARGET;
-  params.max_delay_dev_ratio = SRC_DEFAULT_MAXDELAYDEVRATIO;
-  params.version = NTP_VERSION;
-  params.max_sources = SRC_DEFAULT_MAXSOURCES;
-  params.min_samples = SRC_DEFAULT_MINSAMPLES;
-  params.max_samples = SRC_DEFAULT_MAXSAMPLES;
-
-  status = NSR_AddSource(&rem_addr, type, &params);
+  status = NSR_AddSourceByName(name, port, pool, type, &params);
  switch (status) {
    case NSR_Success:
      break;
+    case NSR_UnresolvedName:
+      /* Try to resolve the name now */
+      NSR_ResolveSources();
+      break;
    case NSR_AlreadyInUse:
      tx_message->status = htons(STT_SOURCEALREADYKNOWN);
      break;
    case NSR_TooManySources:
      tx_message->status = htons(STT_TOOMANYSOURCES);
      break;
-    case NSR_InvalidAF:
-      tx_message->status = htons(STT_INVALIDAF);
+    case NSR_InvalidName:
+      tx_message->status = htons(STT_INVALIDNAME);
      break;
+    case NSR_InvalidAF:
    case NSR_NoSuchSource:
      assert(0);
      break;
@@ -838,6 +792,8 @@ handle_del_source(CMD_Request *rx_message, CMD_Reply *tx_message)
    case NSR_TooManySources:
    case NSR_AlreadyInUse:
    case NSR_InvalidAF:
+    case NSR_InvalidName:
+    case NSR_UnresolvedName:
      assert(0);
      break;
  }
@@ -868,7 +824,7 @@ handle_dfreq(CMD_Request *rx_message, CMD_Reply *tx_message)
  double dfreq;
  dfreq = UTI_FloatNetworkToHost(rx_message->data.dfreq.dfreq);
  LCL_AccumulateDeltaFrequency(dfreq * 1.0e-6);
-  LOG(LOGS_INFO, LOGF_CmdMon, "Accumulated delta freq of %.3fppm", dfreq);
+  LOG(LOGS_INFO, "Accumulated delta freq of %.3fppm", dfreq);
 }

 /* ================================================== */
@@ -881,7 +837,7 @@ handle_doffset(CMD_Request *rx_message, CMD_Reply *tx_message)
  sec = (int32_t)ntohl(rx_message->data.doffset.sec);
  usec = (int32_t)ntohl(rx_message->data.doffset.usec);
  doffset = (double) sec + 1.0e-6 * (double) usec;
-  LOG(LOGS_INFO, LOGF_CmdMon, "Accumulated delta offset of %.6f seconds", doffset);
+  LOG(LOGS_INFO, "Accumulated delta offset of %.6f seconds", doffset);
  LCL_AccumulateOffset(doffset, 0.0);
 }

@@ -898,7 +854,7 @@ handle_tracking(CMD_Request *rx_message, CMD_Reply *tx_message)
  UTI_IPHostToNetwork(&rpt.ip_addr, &tx_message->data.tracking.ip_addr);
  tx_message->data.tracking.stratum = htons(rpt.stratum);
  tx_message->data.tracking.leap_status = htons(rpt.leap_status);
-  UTI_TimevalHostToNetwork(&rpt.ref_time, &tx_message->data.tracking.ref_time);
+  UTI_TimespecHostToNetwork(&rpt.ref_time, &tx_message->data.tracking.ref_time);
  tx_message->data.tracking.current_correction = UTI_FloatHostToNetwork(rpt.current_correction);
  tx_message->data.tracking.last_offset = UTI_FloatHostToNetwork(rpt.last_offset);
  tx_message->data.tracking.rms_offset = UTI_FloatHostToNetwork(rpt.rms_offset);
@@ -916,7 +872,7 @@ static void
 handle_smoothing(CMD_Request *rx_message, CMD_Reply *tx_message)
 {
  RPT_SmoothingReport report;
-  struct timeval now;
+  struct timespec now;

  SCH_GetLastEventTime(&now, NULL, NULL);

@@ -940,7 +896,7 @@ handle_smoothing(CMD_Request *rx_message, CMD_Reply *tx_message)
 static void
 handle_smoothtime(CMD_Request *rx_message, CMD_Reply *tx_message)
 {
-  struct timeval now;
+  struct timespec now;
  int option;

  if (!SMT_IsEnabled()) {
@@ -971,7 +927,7 @@ handle_sourcestats(CMD_Request *rx_message, CMD_Reply *tx_message)
 {
  int status;
  RPT_SourcestatsReport report;
-  struct timeval now_corr;
+  struct timespec now_corr;

  SCH_GetLastEventTime(&now_corr, NULL, NULL);
  status = SRC_ReportSourcestats(ntohl(rx_message->data.sourcestats.index),
@@ -1004,7 +960,7 @@ handle_rtcreport(CMD_Request *rx_message, CMD_Reply *tx_message)
  status = RTC_GetReport(&report);
  if (status) {
    tx_message->reply  = htons(RPY_RTC);
-    UTI_TimevalHostToNetwork(&report.ref_time, &tx_message->data.rtc.ref_time);
+    UTI_TimespecHostToNetwork(&report.ref_time, &tx_message->data.rtc.ref_time);
    tx_message->data.rtc.n_samples = htons(report.n_samples);
    tx_message->data.rtc.n_runs = htons(report.n_runs);
    tx_message->data.rtc.span_seconds = htonl(report.span_seconds);
@@ -1041,7 +997,7 @@ handle_client_accesses_by_index(CMD_Request *rx_message, CMD_Reply *tx_message)
  RPY_ClientAccesses_Client *client;
  int n_indices;
  uint32_t i, j, req_first_index, req_n_clients;
-  struct timeval now;
+  struct timespec now;

  SCH_GetLastEventTime(&now, NULL, NULL);

@@ -1059,9 +1015,6 @@ handle_client_accesses_by_index(CMD_Request *rx_message, CMD_Reply *tx_message)
  tx_message->reply = htons(RPY_CLIENT_ACCESSES_BY_INDEX2);
  tx_message->data.client_accesses_by_index.n_indices = htonl(n_indices);

-  memset(tx_message->data.client_accesses_by_index.clients, 0,
-         sizeof (tx_message->data.client_accesses_by_index.clients));
-
  for (i = req_first_index, j = 0; i < (uint32_t)n_indices && j < req_n_clients; i++) {
    if (!CLG_GetClientAccessReportByIndex(i, &report, &now))
      continue;
@@ -1094,13 +1047,14 @@ handle_manual_list(CMD_Request *rx_message, CMD_Reply *tx_message)
  RPY_ManualListSample *sample;
  RPT_ManualSamplesReport report[MAX_MANUAL_LIST_SAMPLES];

-  tx_message->reply = htons(RPY_MANUAL_LIST);
+  tx_message->reply = htons(RPY_MANUAL_LIST2);
  
  MNL_ReportSamples(report, MAX_MANUAL_LIST_SAMPLES, &n_samples);
  tx_message->data.manual_list.n_samples = htonl(n_samples);
+
  for (i=0; i<n_samples; i++) {
    sample = &tx_message->data.manual_list.samples[i];
-    UTI_TimevalHostToNetwork(&report[i].when, &sample->when);
+    UTI_TimespecHostToNetwork(&report[i].when, &sample->when);
    sample->slewed_offset = UTI_FloatHostToNetwork(report[i].slewed_offset);
    sample->orig_offset = UTI_FloatHostToNetwork(report[i].orig_offset);
    sample->residual = UTI_FloatHostToNetwork(report[i].residual);
@@ -1185,152 +1139,221 @@ handle_server_stats(CMD_Request *rx_message, CMD_Reply *tx_message)
  tx_message->data.server_stats.log_drops = htonl(report.log_drops);
 }

+/* ================================================== */
+
+static void
+handle_ntp_data(CMD_Request *rx_message, CMD_Reply *tx_message)
+{
+  RPT_NTPReport report;
+
+  UTI_IPNetworkToHost(&rx_message->data.ntp_data.ip_addr, &report.remote_addr);
+
+  if (!NSR_GetNTPReport(&report)) {
+    tx_message->status = htons(STT_NOSUCHSOURCE);
+    return;
+  }
+
+  tx_message->reply = htons(RPY_NTP_DATA);
+  UTI_IPHostToNetwork(&report.remote_addr, &tx_message->data.ntp_data.remote_addr);
+  UTI_IPHostToNetwork(&report.local_addr, &tx_message->data.ntp_data.local_addr);
+  tx_message->data.ntp_data.remote_port = htons(report.remote_port);
+  tx_message->data.ntp_data.leap = report.leap;
+  tx_message->data.ntp_data.version = report.version;
+  tx_message->data.ntp_data.mode = report.mode;
+  tx_message->data.ntp_data.stratum = report.stratum;
+  tx_message->data.ntp_data.poll = report.poll;
+  tx_message->data.ntp_data.precision = report.precision;
+  tx_message->data.ntp_data.root_delay = UTI_FloatHostToNetwork(report.root_delay);
+  tx_message->data.ntp_data.root_dispersion = UTI_FloatHostToNetwork(report.root_dispersion);
+  tx_message->data.ntp_data.ref_id = htonl(report.ref_id);
+  UTI_TimespecHostToNetwork(&report.ref_time, &tx_message->data.ntp_data.ref_time);
+  tx_message->data.ntp_data.offset = UTI_FloatHostToNetwork(report.offset);
+  tx_message->data.ntp_data.peer_delay = UTI_FloatHostToNetwork(report.peer_delay);
+  tx_message->data.ntp_data.peer_dispersion = UTI_FloatHostToNetwork(report.peer_dispersion);
+  tx_message->data.ntp_data.response_time = UTI_FloatHostToNetwork(report.response_time);
+  tx_message->data.ntp_data.jitter_asymmetry = UTI_FloatHostToNetwork(report.jitter_asymmetry);
+  tx_message->data.ntp_data.flags = htons((report.tests & RPY_NTP_FLAGS_TESTS) |
+                                          (report.interleaved ? RPY_NTP_FLAG_INTERLEAVED : 0) |
+                                          (report.authenticated ? RPY_NTP_FLAG_AUTHENTICATED : 0));
+  tx_message->data.ntp_data.tx_tss_char = report.tx_tss_char;
+  tx_message->data.ntp_data.rx_tss_char = report.rx_tss_char;
+  tx_message->data.ntp_data.total_tx_count = htonl(report.total_tx_count);
+  tx_message->data.ntp_data.total_rx_count = htonl(report.total_rx_count);
+  tx_message->data.ntp_data.total_valid_count = htonl(report.total_valid_count);
+  memset(tx_message->data.ntp_data.reserved, 0xff, sizeof (tx_message->data.ntp_data.reserved));
+}
+
+/* ================================================== */
+
+static void
+handle_shutdown(CMD_Request *rx_message, CMD_Reply *tx_message)
+{
+  LOG(LOGS_INFO, "Received shutdown command");
+  SCH_QuitProgram();
+}
+
+/* ================================================== */
+
+static void
+handle_ntp_source_name(CMD_Request *rx_message, CMD_Reply *tx_message)
+{
+  IPAddr addr;
+  char *name;
+
+  UTI_IPNetworkToHost(&rx_message->data.ntp_data.ip_addr, &addr);
+  name = NSR_GetName(&addr);
+
+  if (!name) {
+    tx_message->status = htons(STT_NOSUCHSOURCE);
+    return;
+  }
+
+  tx_message->reply = htons(RPY_NTP_SOURCE_NAME);
+
+  /* Avoid compiler warning */
+  if (strlen(name) >= sizeof (tx_message->data.ntp_source_name.name))
+    memcpy(tx_message->data.ntp_source_name.name, name,
+           sizeof (tx_message->data.ntp_source_name.name));
+  else
+    strncpy((char *)tx_message->data.ntp_source_name.name, name,
+            sizeof (tx_message->data.ntp_source_name.name));
+}
+
+/* ================================================== */
+
+static void
+handle_reset(CMD_Request *rx_message, CMD_Reply *tx_message)
+{
+  struct timespec cooked_now, now;
+
+  SRC_ResetSources();
+  SCH_GetLastEventTime(&cooked_now, NULL, &now);
+  LCL_NotifyExternalTimeStep(&now, &cooked_now, 0.0, 0.0);
+}
+
 /* ================================================== */
 /* Read a packet and process it */

 static void
-read_from_cmd_socket(void *anything)
+read_from_cmd_socket(int sock_fd, int event, void *anything)
 {
+  SCK_Message sck_message;
  CMD_Request rx_message;
  CMD_Reply tx_message;
-  int status, read_length, expected_length, rx_message_length;
-  int localhost, allowed, sock_fd, log_index;
-  union sockaddr_all where_from;
-  socklen_t from_length;
-  IPAddr remote_ip;
-  unsigned short remote_port, rx_command;
-  struct timeval now, cooked_now;
+  IPAddr loopback_addr, remote_ip;
+  int read_length, expected_length;
+  int localhost, allowed, log_index;
+  unsigned short rx_command;
+  struct timespec now, cooked_now;

-  rx_message_length = sizeof(rx_message);
-  from_length = sizeof(where_from);
-
-  sock_fd = (long)anything;
-  status = recvfrom(sock_fd, (char *)&rx_message, rx_message_length, 0,
-                    &where_from.sa, &from_length);
-
-  if (status < 0) {
-    LOG(LOGS_WARN, LOGF_CmdMon, "Error [%s] reading from control socket %d",
-        strerror(errno), sock_fd);
+  if (!SCK_ReceiveMessage(sock_fd, &sck_message, 0))
    return;
-  }

-  if (from_length > sizeof (where_from) ||
-      from_length <= sizeof (where_from.sa.sa_family)) {
-    DEBUG_LOG(LOGF_CmdMon, "Read command packet without source address");
-    return;
-  }
-
-  read_length = status;
+  read_length = sck_message.length;

  /* Get current time cheaply */
  SCH_GetLastEventTime(&cooked_now, NULL, &now);

-  UTI_SockaddrToIPAndPort(&where_from.sa, &remote_ip, &remote_port);
+  /* Check if it's from localhost (127.0.0.1, ::1, or Unix domain),
+     or an authorised address */
+  switch (sck_message.addr_type) {
+    case SCK_ADDR_IP:
+      assert(sock_fd == sock_fd4 || sock_fd == sock_fd6);
+      remote_ip = sck_message.remote_addr.ip.ip_addr;
+      SCK_GetLoopbackIPAddress(remote_ip.family, &loopback_addr);
+      localhost = UTI_CompareIPs(&remote_ip, &loopback_addr, NULL) == 0;

-  /* Check if it's from localhost (127.0.0.1, ::1, or Unix domain) */
-  switch (remote_ip.family) {
-    case IPADDR_INET4:
-      assert(sock_fd == sock_fd4);
-      localhost = remote_ip.addr.in4 == INADDR_LOOPBACK;
-      break;
-#ifdef FEAT_IPV6
-    case IPADDR_INET6:
-      assert(sock_fd == sock_fd6);
-      localhost = !memcmp(remote_ip.addr.in6, &in6addr_loopback,
-                          sizeof (in6addr_loopback));
-      break;
-#endif
-    case IPADDR_UNSPEC:
-      /* This should be the Unix domain socket */
-      if (where_from.sa.sa_family != AF_UNIX)
+      if (!localhost && !ADF_IsAllowed(access_auth_table, &remote_ip)) {
+        DEBUG_LOG("Unauthorised host %s",
+                  UTI_IPSockAddrToString(&sck_message.remote_addr.ip));
        return;
+      }
+
+      assert(remote_ip.family != IPADDR_UNSPEC);
+
+      break;
+    case SCK_ADDR_UNIX:
      assert(sock_fd == sock_fdu);
+      remote_ip.family = IPADDR_UNSPEC;
      localhost = 1;
      break;
    default:
-      assert(0);
-  }
-
-  DEBUG_LOG(LOGF_CmdMon, "Received %d bytes from %s fd %d",
-            status, UTI_SockaddrToString(&where_from.sa), sock_fd);
-
-  if (!(localhost || ADF_IsAllowed(access_auth_table, &remote_ip))) {
-    /* The client is not allowed access, so don't waste any more time
-       on him.  Note that localhost is always allowed access
-       regardless of the defined access rules - otherwise, we could
-       shut ourselves out completely! */
-    return;
+      DEBUG_LOG("Unexpected address type");
+      return;
  }

  if (read_length < offsetof(CMD_Request, data) ||
      read_length < offsetof(CMD_Reply, data) ||
-      rx_message.pkt_type != PKT_TYPE_CMD_REQUEST ||
-      rx_message.res1 != 0 ||
-      rx_message.res2 != 0) {
-
+      read_length > sizeof (CMD_Request)) {
    /* We don't know how to process anything like this or an error reply
       would be larger than the request */
-    DEBUG_LOG(LOGF_CmdMon, "Command packet dropped");
+    DEBUG_LOG("Unexpected length");
    return;
  }

-  expected_length = PKL_CommandLength(&rx_message);
-  rx_command = ntohs(rx_message.command);
+  memcpy(&rx_message, sck_message.data, read_length);

-  tx_message.version = PROTO_VERSION_NUMBER;
-  tx_message.pkt_type = PKT_TYPE_CMD_REPLY;
-  tx_message.res1 = 0;
-  tx_message.res2 = 0;
-  tx_message.command = rx_message.command;
-  tx_message.reply = htons(RPY_NULL);
-  tx_message.status = htons(STT_SUCCESS);
-  tx_message.pad1 = 0;
-  tx_message.pad2 = 0;
-  tx_message.pad3 = 0;
-  tx_message.sequence = rx_message.sequence;
-  tx_message.pad4 = 0;
-  tx_message.pad5 = 0;
-
-  if (rx_message.version != PROTO_VERSION_NUMBER) {
-    DEBUG_LOG(LOGF_CmdMon, "Command packet has invalid version (%d != %d)",
-              rx_message.version, PROTO_VERSION_NUMBER);
-
-    if (rx_message.version >= PROTO_VERSION_MISMATCH_COMPAT_SERVER) {
-      tx_message.status = htons(STT_BADPKTVERSION);
-      transmit_reply(&tx_message, &where_from);
-    }
+  if (rx_message.pkt_type != PKT_TYPE_CMD_REQUEST ||
+      rx_message.res1 != 0 ||
+      rx_message.res2 != 0) {
+    DEBUG_LOG("Command packet dropped");
    return;
  }

-  if (rx_command >= N_REQUEST_TYPES ||
-      expected_length < (int)offsetof(CMD_Request, data)) {
-    DEBUG_LOG(LOGF_CmdMon, "Command packet has invalid command %d", rx_command);
-
-    tx_message.status = htons(STT_INVALID);
-    transmit_reply(&tx_message, &where_from);
-    return;
-  }
-
-  if (read_length < expected_length) {
-    DEBUG_LOG(LOGF_CmdMon, "Command packet is too short (%d < %d)", read_length,
-              expected_length);
-
-    tx_message.status = htons(STT_BADPKTLENGTH);
-    transmit_reply(&tx_message, &where_from);
-    return;
-  }
-
-  /* OK, we have a valid message.  Now dispatch on message type and process it. */
-
  log_index = CLG_LogCommandAccess(&remote_ip, &cooked_now);

  /* Don't reply to all requests from hosts other than localhost if the rate
     is excessive */
  if (!localhost && log_index >= 0 && CLG_LimitCommandResponseRate(log_index)) {
-      DEBUG_LOG(LOGF_CmdMon, "Command packet discarded to limit response rate");
+      DEBUG_LOG("Command packet discarded to limit response rate");
      return;
  }

+  expected_length = PKL_CommandLength(&rx_message);
+  rx_command = ntohs(rx_message.command);
+
+  memset(&tx_message, 0, sizeof (tx_message));
+  sck_message.data = &tx_message;
+  sck_message.length = 0;
+
+  tx_message.version = PROTO_VERSION_NUMBER;
+  tx_message.pkt_type = PKT_TYPE_CMD_REPLY;
+  tx_message.command = rx_message.command;
+  tx_message.reply = htons(RPY_NULL);
+  tx_message.status = htons(STT_SUCCESS);
+  tx_message.sequence = rx_message.sequence;
+
+  if (rx_message.version != PROTO_VERSION_NUMBER) {
+    DEBUG_LOG("Command packet has invalid version (%d != %d)",
+              rx_message.version, PROTO_VERSION_NUMBER);
+
+    if (rx_message.version >= PROTO_VERSION_MISMATCH_COMPAT_SERVER) {
+      tx_message.status = htons(STT_BADPKTVERSION);
+      transmit_reply(sock_fd, &sck_message);
+    }
+    return;
+  }
+
+  if (rx_command >= N_REQUEST_TYPES ||
+      expected_length < (int)offsetof(CMD_Request, data)) {
+    DEBUG_LOG("Command packet has invalid command %d", rx_command);
+
+    tx_message.status = htons(STT_INVALID);
+    transmit_reply(sock_fd, &sck_message);
+    return;
+  }
+
+  if (read_length < expected_length) {
+    DEBUG_LOG("Command packet is too short (%d < %d)", read_length,
+              expected_length);
+
+    tx_message.status = htons(STT_BADPKTLENGTH);
+    transmit_reply(sock_fd, &sck_message);
+    return;
+  }
+
+  /* OK, we have a valid message.  Now dispatch on message type and process it. */
+
  if (rx_command >= N_REQUEST_TYPES) {
    /* This should be already handled */
    assert(0);
@@ -1338,7 +1361,7 @@ read_from_cmd_socket(void *anything)
    /* Check level of authority required to issue the command.  All commands
       from the Unix domain socket (which is accessible only by the root and
       chrony user/group) are allowed. */
-    if (where_from.sa.sa_family == AF_UNIX) {
+    if (remote_ip.family == IPADDR_UNSPEC) {
      assert(sock_fd == sock_fdu);
      allowed = 1;
    } else {
@@ -1477,12 +1500,8 @@ read_from_cmd_socket(void *anything)
          handle_cmdaccheck(&rx_message, &tx_message);
          break;

-        case REQ_ADD_SERVER:
-          handle_add_source(NTP_SERVER, &rx_message, &tx_message);
-          break;
-
-        case REQ_ADD_PEER:
-          handle_add_source(NTP_PEER, &rx_message, &tx_message);
+        case REQ_ADD_SOURCE:
+          handle_add_source(&rx_message, &tx_message);
          break;

        case REQ_DEL_SOURCE:
@@ -1573,8 +1592,28 @@ read_from_cmd_socket(void *anything)
          handle_server_stats(&rx_message, &tx_message);
          break;

+        case REQ_NTP_DATA:
+          handle_ntp_data(&rx_message, &tx_message);
+          break;
+
+        case REQ_SHUTDOWN:
+          handle_shutdown(&rx_message, &tx_message);
+          break;
+
+        case REQ_ONOFFLINE:
+          handle_onoffline(&rx_message, &tx_message);
+          break;
+
+        case REQ_NTP_SOURCE_NAME:
+          handle_ntp_source_name(&rx_message, &tx_message);
+          break;
+
+        case REQ_RESET:
+          handle_reset(&rx_message, &tx_message);
+          break;
+
        default:
-          DEBUG_LOG(LOGF_CmdMon, "Unhandled command %d", rx_command);
+          DEBUG_LOG("Unhandled command %d", rx_command);
          tx_message.status = htons(STT_FAILED);
          break;
      }
@@ -1590,7 +1629,7 @@ read_from_cmd_socket(void *anything)
    static int do_it=1;

    if (do_it) {
-      transmit_reply(&tx_message, &where_from);
+      transmit_reply(sock_fd, &sck_message);
    }

 #if 0
--- a/cmdparse.c
+++ b/cmdparse.c
@@ -39,186 +39,137 @@

 /* ================================================== */

-CPS_Status
+int
 CPS_ParseNTPSourceAdd(char *line, CPS_NTP_Source *src)
 {
  char *hostname, *cmd;
-  int n, done;
-  CPS_Status result;
+  int n;
  
  src->port = SRC_DEFAULT_PORT;
  src->params.minpoll = SRC_DEFAULT_MINPOLL;
  src->params.maxpoll = SRC_DEFAULT_MAXPOLL;
+  src->params.connectivity = SRC_ONLINE;
+  src->params.auto_offline = 0;
  src->params.presend_minpoll = SRC_DEFAULT_PRESEND_MINPOLL;
+  src->params.burst = 0;
+  src->params.iburst = 0;
+  src->params.min_stratum = SRC_DEFAULT_MINSTRATUM;
+  src->params.poll_target = SRC_DEFAULT_POLLTARGET;
+  src->params.version = 0;
+  src->params.max_sources = SRC_DEFAULT_MAXSOURCES;
+  src->params.min_samples = SRC_DEFAULT_MINSAMPLES;
+  src->params.max_samples = SRC_DEFAULT_MAXSAMPLES;
+  src->params.filter_length = 0;
+  src->params.interleaved = 0;
+  src->params.sel_options = 0;
+  src->params.nts = 0;
+  src->params.nts_port = SRC_DEFAULT_NTSPORT;
  src->params.authkey = INACTIVE_AUTHKEY;
  src->params.max_delay = SRC_DEFAULT_MAXDELAY;
  src->params.max_delay_ratio = SRC_DEFAULT_MAXDELAYRATIO;
  src->params.max_delay_dev_ratio = SRC_DEFAULT_MAXDELAYDEVRATIO;
-  src->params.online = 1;
-  src->params.auto_offline = 0;
-  src->params.iburst = 0;
-  src->params.min_stratum = SRC_DEFAULT_MINSTRATUM;
-  src->params.poll_target = SRC_DEFAULT_POLLTARGET;
-  src->params.version = NTP_VERSION;
-  src->params.max_sources = SRC_DEFAULT_MAXSOURCES;
-  src->params.min_samples = SRC_DEFAULT_MINSAMPLES;
-  src->params.max_samples = SRC_DEFAULT_MAXSAMPLES;
-  src->params.sel_options = 0;
+  src->params.min_delay = 0.0;
+  src->params.asymmetry = SRC_DEFAULT_ASYMMETRY;
+  src->params.offset = 0.0;

-  result = CPS_Success;
-  
  hostname = line;
  line = CPS_SplitWord(line);

-  if (!*hostname) {
-    result = CPS_BadHost;
-  } else {
-    src->name = hostname;
+  if (!*hostname)
+    return 0;

-    /* Parse subfields */
-    done = 0;
-    do {
-      cmd = line;
-      line = CPS_SplitWord(line);
+  src->name = hostname;

-      if (*cmd) {
-        if (!strcasecmp(cmd, "port")) {
-          if (sscanf(line, "%hu%n", &src->port, &n) != 1) {
-            result = CPS_BadPort;
-            done = 1;
-          } else {
-            line += n;
-          }
-        } else if (!strcasecmp(cmd, "minpoll")) {
-          if (sscanf(line, "%d%n", &src->params.minpoll, &n) != 1) {
-            result = CPS_BadMinpoll;
-            done = 1;
-          } else {
-            line += n;
-          }
-        } else if (!strcasecmp(cmd, "maxpoll")) {
-          if (sscanf(line, "%d%n", &src->params.maxpoll, &n) != 1) {
-            result = CPS_BadMaxpoll;
-            done = 1;
-          } else {
-            line += n;
-          }
-        } else if (!strcasecmp(cmd, "presend")) {
-          if (sscanf(line, "%d%n", &src->params.presend_minpoll, &n) != 1) {
-            result = CPS_BadPresend;
-            done = 1;
-          } else {
-            line += n;
-          }
-        } else if (!strcasecmp(cmd, "maxdelaydevratio")) {
-          if (sscanf(line, "%lf%n", &src->params.max_delay_dev_ratio, &n) != 1) {
-            result = CPS_BadMaxdelaydevratio;
-            done = 1;
-          } else {
-            line += n;
-          }
-        } else if (!strcasecmp(cmd, "maxdelayratio")) {
-          if (sscanf(line, "%lf%n", &src->params.max_delay_ratio, &n) != 1) {
-            result = CPS_BadMaxdelayratio;
-            done = 1;
-          } else {
-            line += n;
-          }
-        } else if (!strcasecmp(cmd, "maxdelay")) {
-          if (sscanf(line, "%lf%n", &src->params.max_delay, &n) != 1) {
-            result = CPS_BadMaxdelay;
-            done = 1;
-          } else {
-            line += n;
-          }
-        } else if (!strcasecmp(cmd, "key")) {
-          if (sscanf(line, "%"SCNu32"%n", &src->params.authkey, &n) != 1 ||
-              src->params.authkey == INACTIVE_AUTHKEY) {
-            result = CPS_BadKey;
-            done = 1;
-          } else {
-            line += n;
-          }
-        } else if (!strcasecmp(cmd, "offline")) {
-          src->params.online = 0;
+  /* Parse options */
+  for (; *line; line += n) {
+    cmd = line;
+    line = CPS_SplitWord(line);
+    n = 0;

-        } else if (!strcasecmp(cmd, "auto_offline")) {
-          src->params.auto_offline = 1;
-        
-        } else if (!strcasecmp(cmd, "iburst")) {
-          src->params.iburst = 1;
-
-        } else if (!strcasecmp(cmd, "minstratum")) {
-          if (sscanf(line, "%d%n", &src->params.min_stratum, &n) != 1) {
-            result = CPS_BadMinstratum;
-            done = 1;
-          } else {
-            line += n;
-          }
-
-        } else if (!strcasecmp(cmd, "polltarget")) {
-          if (sscanf(line, "%d%n", &src->params.poll_target, &n) != 1) {
-            result = CPS_BadPolltarget;
-            done = 1;
-          } else {
-            line += n;
-          }
-
-        } else if (!strcasecmp(cmd, "noselect")) {
-          src->params.sel_options |= SRC_SELECT_NOSELECT;
-        
-        } else if (!strcasecmp(cmd, "prefer")) {
-          src->params.sel_options |= SRC_SELECT_PREFER;
-        
-        } else if (!strcasecmp(cmd, "trust")) {
-          src->params.sel_options |= SRC_SELECT_TRUST;
-
-        } else if (!strcasecmp(cmd, "require")) {
-          src->params.sel_options |= SRC_SELECT_REQUIRE;
-
-        } else if (!strcasecmp(cmd, "version")) {
-          if (sscanf(line, "%d%n", &src->params.version, &n) != 1) {
-            result = CPS_BadVersion;
-            done = 1;
-          } else {
-            line += n;
-          }
-
-        } else if (!strcasecmp(cmd, "maxsources")) {
-          if (sscanf(line, "%d%n", &src->params.max_sources, &n) != 1) {
-            result = CPS_BadMaxsources;
-            done = 1;
-          } else {
-            line += n;
-          }
-
-        } else if (!strcasecmp(cmd, "minsamples")) {
-          if (sscanf(line, "%d%n", &src->params.min_samples, &n) != 1) {
-            result = CPS_BadMinsamples;
-            done = 1;
-          } else {
-            line += n;
-          }
-
-        } else if (!strcasecmp(cmd, "maxsamples")) {
-          if (sscanf(line, "%d%n", &src->params.max_samples, &n) != 1) {
-            result = CPS_BadMaxsamples;
-            done = 1;
-          } else {
-            line += n;
-          }
-
-        } else {
-          result = CPS_BadOption;
-          done = 1;
-        }
-      } else {
-        done = 1;
-      }
-    } while (!done);
+    if (!strcasecmp(cmd, "auto_offline")) {
+      src->params.auto_offline = 1;
+    } else if (!strcasecmp(cmd, "burst")) {
+      src->params.burst = 1;
+    } else if (!strcasecmp(cmd, "iburst")) {
+      src->params.iburst = 1;
+    } else if (!strcasecmp(cmd, "offline")) {
+      src->params.connectivity = SRC_OFFLINE;
+    } else if (!strcasecmp(cmd, "noselect")) {
+      src->params.sel_options |= SRC_SELECT_NOSELECT;
+    } else if (!strcasecmp(cmd, "prefer")) {
+      src->params.sel_options |= SRC_SELECT_PREFER;
+    } else if (!strcasecmp(cmd, "require")) {
+      src->params.sel_options |= SRC_SELECT_REQUIRE;
+    } else if (!strcasecmp(cmd, "trust")) {
+      src->params.sel_options |= SRC_SELECT_TRUST;
+    } else if (!strcasecmp(cmd, "key")) {
+      if (sscanf(line, "%"SCNu32"%n", &src->params.authkey, &n) != 1 ||
+          src->params.authkey == INACTIVE_AUTHKEY)
+        return 0;
+    } else if (!strcasecmp(cmd, "asymmetry")) {
+      if (sscanf(line, "%lf%n", &src->params.asymmetry, &n) != 1)
+        return 0;
+    } else if (!strcasecmp(cmd, "filter")) {
+      if (sscanf(line, "%d%n", &src->params.filter_length, &n) != 1)
+        return 0;
+    } else if (!strcasecmp(cmd, "maxdelay")) {
+      if (sscanf(line, "%lf%n", &src->params.max_delay, &n) != 1)
+        return 0;
+    } else if (!strcasecmp(cmd, "maxdelayratio")) {
+      if (sscanf(line, "%lf%n", &src->params.max_delay_ratio, &n) != 1)
+        return 0;
+    } else if (!strcasecmp(cmd, "maxdelaydevratio")) {
+      if (sscanf(line, "%lf%n", &src->params.max_delay_dev_ratio, &n) != 1)
+        return 0;
+    } else if (!strcasecmp(cmd, "maxpoll")) {
+      if (sscanf(line, "%d%n", &src->params.maxpoll, &n) != 1)
+        return 0;
+    } else if (!strcasecmp(cmd, "maxsamples")) {
+      if (sscanf(line, "%d%n", &src->params.max_samples, &n) != 1)
+        return 0;
+    } else if (!strcasecmp(cmd, "maxsources")) {
+      if (sscanf(line, "%d%n", &src->params.max_sources, &n) != 1)
+        return 0;
+    } else if (!strcasecmp(cmd, "mindelay")) {
+      if (sscanf(line, "%lf%n", &src->params.min_delay, &n) != 1)
+        return 0;
+    } else if (!strcasecmp(cmd, "minpoll")) {
+      if (sscanf(line, "%d%n", &src->params.minpoll, &n) != 1)
+        return 0;
+    } else if (!strcasecmp(cmd, "minsamples")) {
+      if (sscanf(line, "%d%n", &src->params.min_samples, &n) != 1)
+        return 0;
+    } else if (!strcasecmp(cmd, "minstratum")) {
+      if (sscanf(line, "%d%n", &src->params.min_stratum, &n) != 1)
+        return 0;
+    } else if (!strcasecmp(cmd, "nts")) {
+      src->params.nts = 1;
+    } else if (!strcasecmp(cmd, "ntsport")) {
+      if (sscanf(line, "%d%n", &src->params.nts_port, &n) != 1)
+        return 0;
+    } else if (!strcasecmp(cmd, "offset")) {
+      if (sscanf(line, "%lf%n", &src->params.offset, &n) != 1)
+        return 0;
+    } else if (!strcasecmp(cmd, "port")) {
+      if (sscanf(line, "%hu%n", &src->port, &n) != 1)
+        return 0;
+    } else if (!strcasecmp(cmd, "polltarget")) {
+      if (sscanf(line, "%d%n", &src->params.poll_target, &n) != 1)
+        return 0;
+    } else if (!strcasecmp(cmd, "presend")) {
+      if (sscanf(line, "%d%n", &src->params.presend_minpoll, &n) != 1)
+        return 0;
+    } else if (!strcasecmp(cmd, "version")) {
+      if (sscanf(line, "%d%n", &src->params.version, &n) != 1)
+        return 0;
+    } else if (!strcasecmp(cmd, "xleave")) {
+      src->params.interleaved = 1;
+    } else {
+      return 0;
+    }
  }

-  return result;
+  return 1;
 }

 /* ================================================== */
@@ -256,71 +207,6 @@ CPS_ParseLocal(char *line, int *stratum, int *orphan, double *distance)

  return 1;
 }
-/* ================================================== */
-
-void
-CPS_StatusToString(CPS_Status status, char *dest, int len)
-{
-  const char *s = NULL;
-
-  if (len > 0)
-    dest[0] = '\0';
-
-  switch (status) {
-    case CPS_Success:
-      return;
-    case CPS_BadOption:
-      s = "server/peer/pool option";
-      break;
-    case CPS_BadHost:
-      s = "address";
-      break;
-    case CPS_BadPort:
-      s = "port";
-      break;
-    case CPS_BadMinpoll:
-      s = "minpoll";
-      break;
-    case CPS_BadMaxpoll:
-      s = "maxpoll";
-      break;
-    case CPS_BadPresend:
-      s = "presend";
-      break;
-    case CPS_BadMaxdelaydevratio:
-      s = "maxdelaydevratio";
-      break;
-    case CPS_BadMaxdelayratio:
-      s = "maxdelayratio";
-      break;
-    case CPS_BadMaxdelay:
-      s = "maxdelay";
-      break;
-    case CPS_BadKey:
-      s = "key";
-      break;
-    case CPS_BadMinstratum:
-      s = "minstratum";
-      break;
-    case CPS_BadPolltarget:
-      s = "polltarget";
-      break;
-    case CPS_BadVersion:
-      s = "version";
-      break;
-    case CPS_BadMaxsources:
-      s = "maxsources";
-      break;
-    case CPS_BadMinsamples:
-      s = "minsamples";
-      break;
-    case CPS_BadMaxsamples:
-      s = "maxsamples";
-      break;
-  }
-
-  snprintf(dest, len, "Invalid %s", s);
-}

 /* ================================================== */

@@ -382,7 +268,7 @@ CPS_SplitWord(char *line)
 /* ================================================== */

 int
-CPS_ParseKey(char *line, uint32_t *id, const char **hash, char **key)
+CPS_ParseKey(char *line, uint32_t *id, const char **type, char **key)
 {
  char *s1, *s2, *s3, *s4;

@@ -399,10 +285,10 @@ CPS_ParseKey(char *line, uint32_t *id, const char **hash, char **key)
    return 0;

  if (*s3) {
-    *hash = s2;
+    *type = s2;
    *key = s3;
  } else {
-    *hash = "MD5";
+    *type = "MD5";
    *key = s2;
  }

--- a/cmdparse.h
+++ b/cmdparse.h
@@ -30,26 +30,6 @@
 #include "srcparams.h"
 #include "addressing.h"

-typedef enum {
-  CPS_Success,
-  CPS_BadOption,
-  CPS_BadHost,
-  CPS_BadPort,
-  CPS_BadMinpoll,
-  CPS_BadMaxpoll,
-  CPS_BadPresend,
-  CPS_BadMaxdelaydevratio,
-  CPS_BadMaxdelayratio,
-  CPS_BadMaxdelay,
-  CPS_BadKey,
-  CPS_BadMinstratum,
-  CPS_BadPolltarget,
-  CPS_BadVersion,
-  CPS_BadMaxsources,
-  CPS_BadMinsamples,
-  CPS_BadMaxsamples,
-} CPS_Status;
-
 typedef struct {
  char *name;
  unsigned short port;
@@ -57,14 +37,11 @@ typedef struct {
 } CPS_NTP_Source;

 /* Parse a command to add an NTP server or peer */
-extern CPS_Status CPS_ParseNTPSourceAdd(char *line, CPS_NTP_Source *src);
+extern int CPS_ParseNTPSourceAdd(char *line, CPS_NTP_Source *src);
  
 /* Parse a command to enable local reference */
 extern int CPS_ParseLocal(char *line, int *stratum, int *orphan, double *distance);

-/* Get a string describing error status */
-extern void CPS_StatusToString(CPS_Status status, char *dest, int len);
-
 /* Remove extra white-space and comments */
 extern void CPS_NormalizeLine(char *line);

@@ -72,6 +49,6 @@ extern void CPS_NormalizeLine(char *line);
 extern char *CPS_SplitWord(char *line);

 /* Parse a key from keyfile */
-extern int CPS_ParseKey(char *line, uint32_t *id, const char **hash, char **key);
+extern int CPS_ParseKey(char *line, uint32_t *id, const char **type, char **key);

 #endif /* GOT_CMDPARSE_H */
--- a/conf.c
+++ b/conf.c
@@ -3,7 +3,7 @@

 **********************************************************************
 * Copyright (C) Richard P. Curnow  1997-2003
- * Copyright (C) Miroslav Lichvar  2009-2016
+ * Copyright (C) Miroslav Lichvar  2009-2017
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
@@ -57,6 +57,7 @@ static void parse_bindcmdaddress(char *);
 static void parse_broadcast(char *);
 static void parse_clientloglimit(char *);
 static void parse_fallbackdrift(char *);
+static void parse_hwtimestamp(char *);
 static void parse_include(char *);
 static void parse_initstepslew(char *);
 static void parse_leapsecmode(char *);
@@ -78,7 +79,7 @@ static void parse_tempcomp(char *);
 static int restarted = 0;
 static char *rtc_device;
 static int acquisition_port = -1;
-static int ntp_port = 123;
+static int ntp_port = NTP_PORT;
 static char *keys_file = NULL;
 static char *drift_file = NULL;
 static char *rtc_file = NULL;
@@ -89,19 +90,20 @@ static double max_drift = 500000.0; /* in ppm */
 static double max_slew_rate = 1e6 / 12.0; /* in ppm */

 static double max_distance = 3.0;
+static double max_jitter = 1.0;
 static double reselect_distance = 1e-4;
 static double stratum_weight = 1e-3;
 static double combine_limit = 3.0;

 static int cmd_port = DEFAULT_CANDM_PORT;

+static int raw_measurements = 0;
 static int do_log_measurements = 0;
 static int do_log_statistics = 0;
 static int do_log_tracking = 0;
 static int do_log_rtc = 0;
 static int do_log_refclocks = 0;
 static int do_log_tempcomp = 0;
-static int do_dump_on_exit = 0;
 static int log_banner = 32;
 static char *logdir;
 static char *dumpdir;
@@ -147,7 +149,7 @@ static double max_offset;

 /* Maximum and minimum number of samples per source */
 static int max_samples = 0; /* no limit */
-static int min_samples = 0;
+static int min_samples = 6;

 /* Threshold for a time adjustment to be logged to syslog */
 static double log_change_threshold = 1.0;
@@ -181,6 +183,9 @@ static IPAddr bind_cmd_address4, bind_cmd_address6;
 /* Path to the Unix domain command socket. */
 static char *bind_cmd_path;

+/* Path to Samba (ntp_signd) socket. */
+static char *ntp_signd_socket = NULL;
+
 /* Filename to use for storing pid of running chronyd, to prevent multiple
 * chronyds being started. */
 static char *pidfile;
@@ -189,10 +194,10 @@ static char *pidfile;
 static int ntp_ratelimit_enabled = 0;
 static int ntp_ratelimit_interval = 3;
 static int ntp_ratelimit_burst = 8;
-static int ntp_ratelimit_leak = 3;
+static int ntp_ratelimit_leak = 2;
 static int cmd_ratelimit_enabled = 0;
-static int cmd_ratelimit_interval = 1;
-static int cmd_ratelimit_burst = 16;
+static int cmd_ratelimit_interval = -4;
+static int cmd_ratelimit_burst = 8;
 static int cmd_ratelimit_leak = 2;

 /* Smoothing constants */
@@ -218,6 +223,23 @@ static char *leapsec_tz = NULL;
 /* Name of the user to which will be dropped root privileges. */
 static char *user;

+/* NTS cache dir, certificates, private key, and port */
+static char *nts_cachedir = NULL;
+static char *nts_server_cert_file = NULL;
+static char *nts_server_key_file = NULL;
+static int nts_server_port = 11443;
+static int nts_server_processes = 1;
+static int nts_server_connections = 100;
+static int nts_refresh = 2419200; /* 4 weeks */
+static int nts_rotate = 604800; /* 1 week */
+static char *nts_trusted_cert_file = NULL;
+
+/* Flag disabling use of system trusted certificates */
+static int no_system_cert = 0;
+
+/* Array of CNF_HwTsInterface */
+static ARR_Instance hwts_interfaces;
+
 typedef struct {
  NTP_Source_Type type;
  int pool;
@@ -262,7 +284,7 @@ static const char *processed_command;
 static void
 command_parse_error(void)
 {
-    LOG_FATAL(LOGF_Configure, "Could not parse %s directive at line %d%s%s",
+    LOG_FATAL("Could not parse %s directive at line %d%s%s",
        processed_command, line_number, processed_file ? " in file " : "",
        processed_file ? processed_file : "");
 }
@@ -272,7 +294,7 @@ command_parse_error(void)
 static void
 other_parse_error(const char *message)
 {
-    LOG_FATAL(LOGF_Configure, "%s at line %d%s%s",
+    LOG_FATAL("%s at line %d%s%s",
        message, line_number, processed_file ? " in file " : "",
        processed_file ? processed_file : "");
 }
@@ -305,7 +327,7 @@ check_number_of_args(char *line, int num)
  num -= get_number_of_args(line);

  if (num) {
-    LOG_FATAL(LOGF_Configure, "%s arguments for %s directive at line %d%s%s",
+    LOG_FATAL("%s arguments for %s directive at line %d%s%s",
        num > 0 ? "Missing" : "Too many",
        processed_command, line_number, processed_file ? " in file " : "",
        processed_file ? processed_file : "");
@@ -315,10 +337,12 @@ check_number_of_args(char *line, int num)
 /* ================================================== */

 void
-CNF_Initialise(int r)
+CNF_Initialise(int r, int client_only)
 {
  restarted = r;

+  hwts_interfaces = ARR_CreateInstance(sizeof (CNF_HwTsInterface));
+
  init_sources = ARR_CreateInstance(sizeof (IPAddr));
  ntp_sources = ARR_CreateInstance(sizeof (NTP_Source));
  refclock_sources = ARR_CreateInstance(sizeof (RefclockParameters));
@@ -327,13 +351,20 @@ CNF_Initialise(int r)
  ntp_restrictions = ARR_CreateInstance(sizeof (AllowDeny));
  cmd_restrictions = ARR_CreateInstance(sizeof (AllowDeny));

-  dumpdir = Strdup(".");
-  logdir = Strdup(".");
-  bind_cmd_path = Strdup(DEFAULT_COMMAND_SOCKET);
-  pidfile = Strdup("/var/run/chronyd.pid");
-  rtc_device = Strdup("/dev/rtc");
+  dumpdir = Strdup("");
+  logdir = Strdup("");
+  rtc_device = Strdup(DEFAULT_RTC_DEVICE);
  hwclock_file = Strdup(DEFAULT_HWCLOCK_FILE);
  user = Strdup(DEFAULT_USER);
+
+  if (client_only) {
+    cmd_port = ntp_port = 0;
+    bind_cmd_path = Strdup("");
+    pidfile = Strdup("");
+  } else {
+    bind_cmd_path = Strdup(DEFAULT_COMMAND_SOCKET);
+    pidfile = Strdup(DEFAULT_PID_FILE);
+  }
 }

 /* ================================================== */
@@ -343,6 +374,10 @@ CNF_Finalise(void)
 {
  unsigned int i;

+  for (i = 0; i < ARR_GetSize(hwts_interfaces); i++)
+    Free(((CNF_HwTsInterface *)ARR_GetElement(hwts_interfaces, i))->name);
+  ARR_DestroyInstance(hwts_interfaces);
+
  for (i = 0; i < ARR_GetSize(ntp_sources); i++)
    Free(((NTP_Source *)ARR_GetElement(ntp_sources, i))->params.name);

@@ -361,6 +396,7 @@ CNF_Finalise(void)
  Free(leapsec_tz);
  Free(logdir);
  Free(bind_cmd_path);
+  Free(ntp_signd_socket);
  Free(pidfile);
  Free(rtc_device);
  Free(rtc_file);
@@ -368,6 +404,10 @@ CNF_Finalise(void)
  Free(mail_user_on_change);
  Free(tempcomp_sensor_file);
  Free(tempcomp_point_file);
+  Free(nts_cachedir);
+  Free(nts_server_cert_file);
+  Free(nts_server_key_file);
+  Free(nts_trusted_cert_file);
 }

 /* ================================================== */
@@ -380,14 +420,7 @@ CNF_ReadFile(const char *filename)
  char line[2048];
  int i;

-  in = fopen(filename, "r");
-  if (!in) {
-    LOG_FATAL(LOGF_Configure, "Could not open configuration file %s : %s",
-              filename, strerror(errno));
-    return;
-  }
-
-  DEBUG_LOG(LOGF_Configure, "Reading %s", filename);
+  in = UTI_OpenFile(NULL, filename, NULL, 'R', 0);

  for (i = 1; fgets(line, sizeof(line), in); i++) {
    CNF_ParseLine(filename, i, line);
@@ -453,11 +486,13 @@ CNF_ParseLine(const char *filename, int number, char *line)
  } else if (!strcasecmp(command, "dumpdir")) {
    parse_string(p, &dumpdir);
  } else if (!strcasecmp(command, "dumponexit")) {
-    do_dump_on_exit = parse_null(p);
+    /* Silently ignored */
  } else if (!strcasecmp(command, "fallbackdrift")) {
    parse_fallbackdrift(p);
  } else if (!strcasecmp(command, "hwclockfile")) {
    parse_string(p, &hwclock_file);
+  } else if (!strcasecmp(command, "hwtimestamp")) {
+    parse_hwtimestamp(p);
  } else if (!strcasecmp(command, "include")) {
    parse_include(p);
  } else if (!strcasecmp(command, "initstepslew")) {
@@ -494,6 +529,10 @@ CNF_ParseLine(const char *filename, int number, char *line)
    parse_double(p, &max_distance);
  } else if (!strcasecmp(command, "maxdrift")) {
    parse_double(p, &max_drift);
+  } else if (!strcasecmp(command, "maxjitter")) {
+    parse_double(p, &max_jitter);
+  } else if (!strcasecmp(command, "maxntsconnections")) {
+    parse_int(p, &nts_server_connections);
  } else if (!strcasecmp(command, "maxsamples")) {
    parse_int(p, &max_samples);
  } else if (!strcasecmp(command, "maxslewrate")) {
@@ -506,6 +545,26 @@ CNF_ParseLine(const char *filename, int number, char *line)
    parse_int(p, &min_sources);
  } else if (!strcasecmp(command, "noclientlog")) {
    no_client_log = parse_null(p);
+  } else if (!strcasecmp(command, "nosystemcert")) {
+    no_system_cert = parse_null(p);
+  } else if (!strcasecmp(command, "ntpsigndsocket")) {
+    parse_string(p, &ntp_signd_socket);
+  } else if (!strcasecmp(command, "ntstrustedcerts")) {
+    parse_string(p, &nts_trusted_cert_file);
+  } else if (!strcasecmp(command, "ntscachedir")) {
+    parse_string(p, &nts_cachedir);
+  } else if (!strcasecmp(command, "ntsport")) {
+    parse_int(p, &nts_server_port);
+  } else if (!strcasecmp(command, "ntsprocesses")) {
+    parse_int(p, &nts_server_processes);
+  } else if (!strcasecmp(command, "ntsrefresh")) {
+    parse_int(p, &nts_refresh);
+  } else if (!strcasecmp(command, "ntsrotate")) {
+    parse_int(p, &nts_rotate);
+  } else if (!strcasecmp(command, "ntsservercert")) {
+    parse_string(p, &nts_server_cert_file);
+  } else if (!strcasecmp(command, "ntsserverkey")) {
+    parse_string(p, &nts_server_key_file);
  } else if (!strcasecmp(command, "peer")) {
    parse_source(p, NTP_PEER, 0);
  } else if (!strcasecmp(command, "pidfile")) {
@@ -547,7 +606,7 @@ CNF_ParseLine(const char *filename, int number, char *line)
             !strcasecmp(command, "generatecommandkey") ||
             !strcasecmp(command, "linux_freq_scale") ||
             !strcasecmp(command, "linux_hz")) {
-    LOG(LOGS_WARN, LOGF_Configure, "%s directive is no longer supported", command);
+    LOG(LOGS_WARN, "%s directive is no longer supported", command);
  } else {
    other_parse_error("Invalid command");
  }
@@ -604,17 +663,13 @@ parse_null(char *line)
 static void
 parse_source(char *line, NTP_Source_Type type, int pool)
 {
-  CPS_Status status;
  NTP_Source source;
-  char str[64];

  source.type = type;
  source.pool = pool;
-  status = CPS_ParseNTPSourceAdd(line, &source.params);

-  if (status != CPS_Success) {
-    CPS_StatusToString(status, str, sizeof (str));
-    other_parse_error(str);
+  if (!CPS_ParseNTPSourceAdd(line, &source.params)) {
+    command_parse_error();
    return;
  }

@@ -657,8 +712,9 @@ static void
 parse_refclock(char *line)
 {
  int n, poll, dpoll, filter_length, pps_rate, min_samples, max_samples, sel_options;
+  int max_lock_age, pps_forced, stratum, tai;
  uint32_t ref_id, lock_ref_id;
-  double offset, delay, precision, max_dispersion;
+  double offset, delay, precision, max_dispersion, pulse_width;
  char *p, *cmd, *name, *param;
  unsigned char ref[5];
  RefclockParameters *refclock;
@@ -666,6 +722,7 @@ parse_refclock(char *line)
  poll = 4;
  dpoll = 0;
  filter_length = 64;
+  pps_forced = 0;
  pps_rate = 0;
  min_samples = SRC_DEFAULT_MINSAMPLES;
  max_samples = SRC_DEFAULT_MAXSAMPLES;
@@ -674,8 +731,12 @@ parse_refclock(char *line)
  delay = 1e-9;
  precision = 0.0;
  max_dispersion = 0.0;
+  pulse_width = 0.0;
  ref_id = 0;
+  max_lock_age = 2;
  lock_ref_id = 0;
+  stratum = 0;
+  tai = 0;

  if (!*line) {
    command_parse_error();
@@ -725,6 +786,9 @@ parse_refclock(char *line)
    } else if (!strcasecmp(cmd, "minsamples")) {
      if (sscanf(line, "%d%n", &min_samples, &n) != 1)
        break;
+    } else if (!strcasecmp(cmd, "maxlockage")) {
+      if (sscanf(line, "%d%n", &max_lock_age, &n) != 1)
+        break;
    } else if (!strcasecmp(cmd, "maxsamples")) {
      if (sscanf(line, "%d%n", &max_samples, &n) != 1)
        break;
@@ -734,12 +798,25 @@ parse_refclock(char *line)
    } else if (!strcasecmp(cmd, "delay")) {
      if (sscanf(line, "%lf%n", &delay, &n) != 1)
        break;
+    } else if (!strcasecmp(cmd, "pps")) {
+      n = 0;
+      pps_forced = 1;
    } else if (!strcasecmp(cmd, "precision")) {
      if (sscanf(line, "%lf%n", &precision, &n) != 1)
        break;
    } else if (!strcasecmp(cmd, "maxdispersion")) {
      if (sscanf(line, "%lf%n", &max_dispersion, &n) != 1)
        break;
+    } else if (!strcasecmp(cmd, "stratum")) {
+      if (sscanf(line, "%d%n", &stratum, &n) != 1 ||
+          stratum >= NTP_MAX_STRATUM || stratum < 0)
+        break;
+    } else if (!strcasecmp(cmd, "tai")) {
+      n = 0;
+      tai = 1;
+    } else if (!strcasecmp(cmd, "width")) {
+      if (sscanf(line, "%lf%n", &pulse_width, &n) != 1)
+        break;
    } else if (!strcasecmp(cmd, "noselect")) {
      n = 0;
      sel_options |= SRC_SELECT_NOSELECT;
@@ -769,15 +846,20 @@ parse_refclock(char *line)
  refclock->driver_poll = dpoll;
  refclock->poll = poll;
  refclock->filter_length = filter_length;
+  refclock->pps_forced = pps_forced;
  refclock->pps_rate = pps_rate;
  refclock->min_samples = min_samples;
  refclock->max_samples = max_samples;
  refclock->sel_options = sel_options;
+  refclock->stratum = stratum;
+  refclock->tai = tai;
  refclock->offset = offset;
  refclock->delay = delay;
  refclock->precision = precision;
  refclock->max_dispersion = max_dispersion;
+  refclock->pulse_width = pulse_width;
  refclock->ref_id = ref_id;
+  refclock->max_lock_age = max_lock_age;
  refclock->lock_ref_id = lock_ref_id;
 }

@@ -791,7 +873,10 @@ parse_log(char *line)
    log_name = line;
    line = CPS_SplitWord(line);
    if (*log_name) {
-      if (!strcmp(log_name, "measurements")) {
+      if (!strcmp(log_name, "rawmeasurements")) {
+        do_log_measurements = 1;
+        raw_measurements = 1;
+      } else if (!strcmp(log_name, "measurements")) {
        do_log_measurements = 1;
      } else if (!strcmp(log_name, "statistics")) {
        do_log_statistics = 1;
@@ -851,7 +936,7 @@ parse_initstepslew(char *line)
      if (DNS_Name2IPAddress(hostname, &ip_addr, 1) == DNS_Success) {
        ARR_AppendElement(init_sources, &ip_addr);
      } else {
-        LOG(LOGS_WARN, LOGF_Configure, "Could not resolve address of initstepslew server %s", hostname);
+        LOG(LOGS_WARN, "Could not resolve address of initstepslew server %s", hostname);
      }
    }
  }
@@ -1028,7 +1113,7 @@ parse_allow_deny(char *line, ARR_Instance restrictions, int allow)
      }

    } else {
-      if (DNS_Name2IPAddress(p, &ip_addr, 1) == DNS_Success) {
+      if (!slashpos && DNS_Name2IPAddress(p, &ip_addr, 1) == DNS_Success) {
        new_node = (AllowDeny *)ARR_GetNewElement(restrictions);
        new_node->allow = allow;
        new_node->all = all;
@@ -1143,7 +1228,7 @@ parse_broadcast(char *line)
    }
  } else {
    /* default port */
-    port = 123;
+    port = NTP_PORT;
  }

  destination = (NTP_Broadcast_Destination *)ARR_GetNewElement(broadcasts);
@@ -1219,16 +1304,96 @@ parse_tempcomp(char *line)

 /* ================================================== */

+static void
+parse_hwtimestamp(char *line)
+{
+  CNF_HwTsInterface *iface;
+  char *p, filter[5];
+  int n;
+
+  if (!*line) {
+    command_parse_error();
+    return;
+  }
+
+  p = line;
+  line = CPS_SplitWord(line);
+
+  iface = ARR_GetNewElement(hwts_interfaces);
+  iface->name = Strdup(p);
+  iface->minpoll = 0;
+  iface->min_samples = 2;
+  iface->max_samples = 16;
+  iface->nocrossts = 0;
+  iface->rxfilter = CNF_HWTS_RXFILTER_ANY;
+  iface->precision = 100.0e-9;
+  iface->tx_comp = 0.0;
+  iface->rx_comp = 0.0;
+
+  for (p = line; *p; line += n, p = line) {
+    line = CPS_SplitWord(line);
+
+    if (!strcasecmp(p, "maxsamples")) {
+      if (sscanf(line, "%d%n", &iface->max_samples, &n) != 1)
+        break;
+    } else if (!strcasecmp(p, "minpoll")) {
+      if (sscanf(line, "%d%n", &iface->minpoll, &n) != 1)
+        break;
+    } else if (!strcasecmp(p, "minsamples")) {
+      if (sscanf(line, "%d%n", &iface->min_samples, &n) != 1)
+        break;
+    } else if (!strcasecmp(p, "precision")) {
+      if (sscanf(line, "%lf%n", &iface->precision, &n) != 1)
+        break;
+    } else if (!strcasecmp(p, "rxcomp")) {
+      if (sscanf(line, "%lf%n", &iface->rx_comp, &n) != 1)
+        break;
+    } else if (!strcasecmp(p, "txcomp")) {
+      if (sscanf(line, "%lf%n", &iface->tx_comp, &n) != 1)
+        break;
+    } else if (!strcasecmp(p, "rxfilter")) {
+      if (sscanf(line, "%4s%n", filter, &n) != 1)
+        break;
+      if (!strcasecmp(filter, "none"))
+        iface->rxfilter = CNF_HWTS_RXFILTER_NONE;
+      else if (!strcasecmp(filter, "ntp"))
+        iface->rxfilter = CNF_HWTS_RXFILTER_NTP;
+      else if (!strcasecmp(filter, "all"))
+        iface->rxfilter = CNF_HWTS_RXFILTER_ALL;
+      else
+        break;
+    } else if (!strcasecmp(p, "nocrossts")) {
+      n = 0;
+      iface->nocrossts = 1;
+    } else {
+      break;
+    }
+  }
+
+  if (*p)
+    command_parse_error();
+}
+
+/* ================================================== */
+
 static void
 parse_include(char *line)
 {
  glob_t gl;
  size_t i;
+  int r;

  check_number_of_args(line, 1);

-  if (glob(line, 0, NULL, &gl)) {
-    DEBUG_LOG(LOGF_Configure, "glob of %s failed", line);
+  if ((r = glob(line,
+#ifdef GLOB_NOMAGIC
+                GLOB_NOMAGIC |
+#endif
+                GLOB_ERR, NULL, &gl)) != 0) {
+    if (r != GLOB_NOMATCH)
+      LOG_FATAL("Could not search for files matching %s", line);
+
+    DEBUG_LOG("glob of %s failed", line);
    return;
  }

@@ -1245,9 +1410,6 @@ CNF_CreateDirs(uid_t uid, gid_t gid)
 {
  char *dir;

-  UTI_CreateDirAndParents(logdir, 0755, uid, gid);
-  UTI_CreateDirAndParents(dumpdir, 0755, uid, gid);
-
  /* Create a directory for the Unix domain command socket */
  if (bind_cmd_path[0]) {
    dir = UTI_PathToDir(bind_cmd_path);
@@ -1257,12 +1419,17 @@ CNF_CreateDirs(uid_t uid, gid_t gid)
       existed.  It MUST NOT be accessible by others as permissions on Unix
       domain sockets are ignored on some systems (e.g. Solaris). */
    if (!UTI_CheckDirPermissions(dir, 0770, uid, gid)) {
-      LOG(LOGS_WARN, LOGF_Configure, "Disabled command socket %s", bind_cmd_path);
+      LOG(LOGS_WARN, "Disabled command socket %s", bind_cmd_path);
      bind_cmd_path[0] = '\0';
    }

    Free(dir);
  }
+
+  if (logdir[0])
+    UTI_CreateDirAndParents(logdir, 0755, uid, gid);
+  if (dumpdir[0])
+    UTI_CreateDirAndParents(dumpdir, 0755, uid, gid);
 }

 /* ================================================== */
@@ -1283,7 +1450,7 @@ CNF_AddInitSources(void)
    ntp_addr.ip_addr = *(IPAddr *)ARR_GetElement(init_sources, i);
    ntp_addr.port = cps_source.port;
    cps_source.params.iburst = 1;
-    cps_source.params.online = 0;
+    cps_source.params.connectivity = SRC_OFFLINE;

    NSR_AddSource(&ntp_addr, NTP_SERVER, &cps_source.params);
  }
@@ -1391,8 +1558,9 @@ CNF_GetDumpDir(void)
 /* ================================================== */

 int
-CNF_GetLogMeasurements(void)
+CNF_GetLogMeasurements(int *raw)
 {
+  *raw = raw_measurements;
  return do_log_measurements;
 }

@@ -1470,14 +1638,6 @@ CNF_GetRtcDevice(void)

 /* ================================================== */

-int
-CNF_GetDumpOnExit(void)
-{
-  return do_dump_on_exit;
-}
-
-/* ================================================== */
-
 double
 CNF_GetMaxUpdateSkew(void)
 {
@@ -1526,6 +1686,14 @@ CNF_GetMaxDistance(void)

 /* ================================================== */

+double
+CNF_GetMaxJitter(void)
+{
+  return max_jitter;
+}
+
+/* ================================================== */
+
 double
 CNF_GetReselectDistance(void)
 {
@@ -1650,7 +1818,7 @@ CNF_SetupAccessRestrictions(void)
    node = ARR_GetElement(ntp_restrictions, i);
    status = NCR_AddAccessRestriction(&node->ip, node->subnet_bits, node->allow, node->all);
    if (!status) {
-      LOG_FATAL(LOGF_Configure, "Bad subnet in %s/%d", UTI_IPToString(&node->ip), node->subnet_bits);
+      LOG_FATAL("Bad subnet in %s/%d", UTI_IPToString(&node->ip), node->subnet_bits);
    }
  }

@@ -1658,7 +1826,7 @@ CNF_SetupAccessRestrictions(void)
    node = ARR_GetElement(cmd_restrictions, i);
    status = CAM_AddAccessRestriction(&node->ip, node->subnet_bits, node->allow, node->all);
    if (!status) {
-      LOG_FATAL(LOGF_Configure, "Bad subnet in %s/%d", UTI_IPToString(&node->ip), node->subnet_bits);
+      LOG_FATAL("Bad subnet in %s/%d", UTI_IPToString(&node->ip), node->subnet_bits);
    }
  }

@@ -1740,6 +1908,14 @@ CNF_GetBindCommandAddress(int family, IPAddr *addr)

 /* ================================================== */

+char *
+CNF_GetNtpSigndSocket(void)
+{
+  return ntp_signd_socket;
+}
+
+/* ================================================== */
+
 char *
 CNF_GetPidFile(void)
 {
@@ -1877,3 +2053,95 @@ CNF_GetInitStepThreshold(void)
 {
  return init_slew_threshold;
 }
+
+/* ================================================== */
+
+int
+CNF_GetHwTsInterface(unsigned int index, CNF_HwTsInterface **iface)
+{
+  if (index >= ARR_GetSize(hwts_interfaces))
+    return 0;
+
+  *iface = (CNF_HwTsInterface *)ARR_GetElement(hwts_interfaces, index);
+  return 1;
+}
+
+/* ================================================== */
+
+char *
+CNF_GetNtsCacheDir(void)
+{
+  return nts_cachedir;
+}
+
+/* ================================================== */
+
+char *
+CNF_GetNtsServerCertFile(void)
+{
+  return nts_server_cert_file;
+}
+
+/* ================================================== */
+
+char *
+CNF_GetNtsServerKeyFile(void)
+{
+  return nts_server_key_file;
+}
+
+/* ================================================== */
+
+int
+CNF_GetNtsServerPort(void)
+{
+  return nts_server_port;
+}
+
+/* ================================================== */
+
+int
+CNF_GetNtsServerProcesses(void)
+{
+  return nts_server_processes;
+}
+
+/* ================================================== */
+
+int
+CNF_GetNtsServerConnections(void)
+{
+  return nts_server_connections;
+}
+
+/* ================================================== */
+
+int
+CNF_GetNtsRefresh(void)
+{
+  return nts_refresh;
+}
+
+/* ================================================== */
+
+int
+CNF_GetNtsRotate(void)
+{
+  return nts_rotate;
+}
+
+/* ================================================== */
+
+char *
+CNF_GetNtsTrustedCertFile(void)
+{
+  return nts_trusted_cert_file;
+}
+
+/* ================================================== */
+
+int
+CNF_GetNoSystemCert(void)
+{
+  return no_system_cert;
+}
--- a/conf.h
+++ b/conf.h
@@ -31,7 +31,7 @@
 #include "addressing.h"
 #include "reference.h"

-extern void CNF_Initialise(int restarted);
+extern void CNF_Initialise(int restarted, int client_only);
 extern void CNF_Finalise(void);

 extern char *CNF_GetRtcDevice(void);
@@ -52,7 +52,7 @@ extern char *CNF_GetDriftFile(void);
 extern char *CNF_GetLogDir(void);
 extern char *CNF_GetDumpDir(void);
 extern int CNF_GetLogBanner(void);
-extern int CNF_GetLogMeasurements(void);
+extern int CNF_GetLogMeasurements(int *raw);
 extern int CNF_GetLogStatistics(void);
 extern int CNF_GetLogTracking(void);
 extern int CNF_GetLogRtc(void);
@@ -60,7 +60,6 @@ extern int CNF_GetLogRefclocks(void);
 extern int CNF_GetLogTempComp(void);
 extern char *CNF_GetKeysFile(void);
 extern char *CNF_GetRtcFile(void);
-extern int CNF_GetDumpOnExit(void);
 extern int CNF_GetManualEnabled(void);
 extern int CNF_GetCommandPort(void);
 extern int CNF_GetRtcOnUtc(void);
@@ -76,6 +75,7 @@ extern void CNF_GetBindAddress(int family, IPAddr *addr);
 extern void CNF_GetBindAcquisitionAddress(int family, IPAddr *addr);
 extern void CNF_GetBindCommandAddress(int family, IPAddr *addr);
 extern char *CNF_GetBindCommandPath(void);
+extern char *CNF_GetNtpSigndSocket(void);
 extern char *CNF_GetPidFile(void);
 extern REF_LeapMode CNF_GetLeapSecMode(void);
 extern char *CNF_GetLeapSecTimezone(void);
@@ -88,6 +88,7 @@ extern double CNF_GetCorrectionTimeRatio(void);
 extern double CNF_GetMaxSlewRate(void);

 extern double CNF_GetMaxDistance(void);
+extern double CNF_GetMaxJitter(void);
 extern double CNF_GetReselectDistance(void);
 extern double CNF_GetStratumWeight(void);
 extern double CNF_GetCombineLimit(void);
@@ -117,4 +118,36 @@ extern char *CNF_GetHwclockFile(void);
 extern int CNF_GetInitSources(void);
 extern double CNF_GetInitStepThreshold(void);

+typedef enum {
+  CNF_HWTS_RXFILTER_ANY,
+  CNF_HWTS_RXFILTER_NONE,
+  CNF_HWTS_RXFILTER_NTP,
+  CNF_HWTS_RXFILTER_ALL,
+} CNF_HwTs_RxFilter;
+
+typedef struct {
+  char *name;
+  int minpoll;
+  int min_samples;
+  int max_samples;
+  int nocrossts;
+  CNF_HwTs_RxFilter rxfilter;
+  double precision;
+  double tx_comp;
+  double rx_comp;
+} CNF_HwTsInterface;
+
+extern int CNF_GetHwTsInterface(unsigned int index, CNF_HwTsInterface **iface);
+
+extern char *CNF_GetNtsCacheDir(void);
+extern char *CNF_GetNtsServerCertFile(void);
+extern char *CNF_GetNtsServerKeyFile(void);
+extern int CNF_GetNtsServerPort(void);
+extern int CNF_GetNtsServerProcesses(void);
+extern int CNF_GetNtsServerConnections(void);
+extern int CNF_GetNtsRefresh(void);
+extern int CNF_GetNtsRotate(void);
+extern char *CNF_GetNtsTrustedCertFile(void);
+extern int CNF_GetNoSystemCert(void);
+
 #endif /* GOT_CONF_H */
--- a/426
+++ b/426
@@ -4,7 +4,9 @@
 # chronyd/chronyc - Programs for keeping computer clocks accurate.
 #
 # Copyright (C) Richard P. Curnow  1997-2003
-# Copyright (C) Miroslav Lichvar  2009, 2012-2015
+# Copyright (C) Bryan Christianson  2016
+# Copyright (C) Miroslav Lichvar  2009, 2012-2018
+# Copyright (C) Stefan R. Filipek  2019
 #
 # =======================================================================

@@ -24,6 +26,7 @@ test_code () {
  printf "%s" "Checking for $name : "

  (
+    echo "#include \"config.h\""
    for h in $headers; do
      echo "#include <$h>"
    done
@@ -52,6 +55,34 @@ test_code () {
  return $result
 }
 #}}}
+#{{{ test_executable
+test_executable () {
+  name=$1
+  executable=$2
+  options=$3
+
+  printf "%s" "Checking for $name : "
+
+  echo $executable $options >> config.log
+  $executable $options >> config.log 2>&1
+
+  if [ $? -eq 0 ]
+  then
+    echo "Yes"
+    result=0
+  else
+    echo "No"
+    result=1
+  fi
+  echo >> config.log
+  return $result
+}
+#}}}
+#{{{ pkg_config
+pkg_config () {
+  $PKG_CONFIG "$@" 2>> config.log
+}
+#}}}
 #{{{ usage
 usage () {
  cat <<EOF
@@ -79,13 +110,15 @@ For better control, use the options below.
  --disable-readline     Disable line editing support
  --without-readline     Don't use GNU readline even if it is available
  --without-editline     Don't use editline even if it is available
-  --readline-dir=DIR     Specify parent of readline include and lib directories
-  --readline-inc-dir=DIR Specify where readline include directory is
-  --readline-lib-dir=DIR Specify where readline lib directory is
+  --with-readline-includes=DIR Specify where readline include directory is
+  --with-readline-library=DIR Specify where readline lib directory is
  --with-ncurses-library=DIR Specify where ncurses lib directory is
  --disable-sechash      Disable support for hashes other than MD5
+  --without-nettle       Don't use nettle even if it is available
  --without-nss          Don't use NSS even if it is available
  --without-tomcrypt     Don't use libtomcrypt even if it is available
+  --disable-nts          Disable NTS support
+  --without-gnutls       Don't use gnutls even if it is available
  --disable-cmdmon       Disable command and monitoring support
  --disable-ntp          Disable NTP support
  --disable-refclock     Disable reference clock support
@@ -99,10 +132,15 @@ For better control, use the options below.
  --without-seccomp      Don't use seccomp even if it is available
  --disable-asyncdns     Disable asynchronous name resolving
  --disable-forcednsretry Don't retry on permanent DNS error
+  --without-clock-gettime Don't use clock_gettime() even if it is available
+  --disable-timestamping Disable support for SW/HW timestamping
+  --enable-ntp-signd     Enable support for MS-SNTP authentication in Samba
  --with-ntp-era=SECONDS Specify earliest assumed NTP time in seconds
                         since 1970-01-01 [50*365 days ago]
  --with-user=USER       Specify default chronyd user [root]
  --with-hwclockfile=PATH Specify default path to hwclock(8) adjtime file
+  --with-pidfile=PATH    Specify default pidfile [/var/run/chrony/chronyd.pid]
+  --with-rtcdevice=PATH  Specify default path to RTC device [/dev/rtc]
  --with-sendmail=PATH   Path to sendmail binary [/usr/lib/sendmail]
  --enable-debug         Enable debugging support

@@ -114,7 +152,7 @@ Fine tuning of the installation directories:
  --mandir=DIR           man documentation [DATAROOTDIR/man]
  --docdir=DIR           documentation root [DATAROOTDIR/doc/chrony]
  --localstatedir=DIR    modifiable single-machine data [/var]
-  --chronysockdir=DIR    location for chrony sockets [LOCALSTATEDIR/run/chrony]
+  --chronyrundir=DIR     location for chrony sockets [LOCALSTATEDIR/run/chrony]
  --chronyvardir=DIR     location for chrony data [LOCALSTATEDIR/lib/chrony]

 Overriding system detection when cross-compiling:
@@ -129,6 +167,11 @@ Some influential environment variables:
              headers in a nonstandard directory <include dir>
  LDFLAGS     linker flags, e.g. -L<lib dir> if you have libraries in a
              nonstandard directory <lib dir>
+  PKG_CONFIG  path to pkg-config utility
+  PKG_CONFIG_PATH
+              directories to add to pkg-config's search path
+  PKG_CONFIG_LIBDIR
+              path overriding pkg-config's built-in search path

 Use these variables to override the choices made by \`configure' or to help
 it to find libraries and programs with nonstandard names/locations.
@@ -146,13 +189,6 @@ add_def () {
  fi
 }
 #}}}
-#{{{ pkg_config
-pkg_config () {
-  type pkg-config > /dev/null 2> /dev/null || return 1
-
-  pkg-config $@ 2> /dev/null
-}
-#}}}
 #{{{ get_features
 get_features () {
  ff=1
@@ -178,11 +214,11 @@ OPERATINGSYSTEM=`uname -s`
 VERSION=`uname -r`
 MACHINE=`uname -m`

+LIBS=""
 EXTRA_LIBS=""
 EXTRA_CLI_LIBS=""
 EXTRA_OBJECTS=""
-EXTRA_DEFS=""
-SYSDEFS=""
+EXTRA_CLI_OBJECTS=""

 feat_debug=0
 feat_cmdmon=1
@@ -192,8 +228,11 @@ feat_readline=1
 try_readline=1
 try_editline=1
 feat_sechash=1
+try_nettle=1
 try_nss=1
 try_tomcrypt=1
+feat_nts=1
+try_gnutls=1
 feat_rtc=1
 try_rtc=0
 feat_droproot=1
@@ -213,9 +252,17 @@ try_setsched=0
 try_lockmem=0
 feat_asyncdns=1
 feat_forcednsretry=1
+try_clock_gettime=1
+try_recvmmsg=1
+feat_timestamping=1
+try_timestamping=0
+feat_ntp_signd=0
 ntp_era_split=""
+use_pthread=0
 default_user="root"
 default_hwclockfile=""
+default_pidfile="/var/run/chrony/chronyd.pid"
+default_rtcdevice="/dev/rtc"
 mail_program="/usr/lib/sendmail"

 for option
@@ -269,8 +316,8 @@ do
    --localstatedir=* )
      SETLOCALSTATEDIR=`echo $option | sed -e 's/^.*=//;'`
    ;;
-    --chronysockdir=* )
-      SETCHRONYSOCKDIR=`echo $option | sed -e 's/^.*=//;'`
+    --chronyrundir=* | --chronysockdir=* )
+      SETCHRONYRUNDIR=`echo $option | sed -e 's/^.*=//;'`
    ;;
    --chronyvardir=* )
      SETCHRONYVARDIR=`echo $option | sed -e 's/^.*=//;'`
@@ -317,6 +364,15 @@ do
    --disable-forcednsretry)
      feat_forcednsretry=0
    ;;
+    --without-clock-gettime)
+      try_clock_gettime=0
+    ;;
+    --disable-timestamping)
+      feat_timestamping=0
+    ;;
+    --enable-ntp-signd)
+      feat_ntp_signd=1
+    ;;
    --with-ntp-era=* )
      ntp_era_split=`echo $option | sed -e 's/^.*=//;'`
    ;;
@@ -326,18 +382,33 @@ do
    --with-hwclockfile=* )
      default_hwclockfile=`echo $option | sed -e 's/^.*=//;'`
    ;;
+    --with-pidfile=* )
+      default_pidfile=`echo $option | sed -e 's/^.*=//;'`
+    ;;
+    --with-rtcdevice=* )
+      default_rtcdevice=`echo $option | sed -e 's/^.*=//;'`
+    ;;
    --with-sendmail=* )
      mail_program=`echo $option | sed -e 's/^.*=//;'`
    ;;
    --disable-sechash )
      feat_sechash=0
    ;;
+    --without-nettle )
+      try_nettle=0
+    ;;
    --without-nss )
      try_nss=0
    ;;
    --without-tomcrypt )
      try_tomcrypt=0
    ;;
+    --disable-nts )
+      feat_nts=0
+    ;;
+    --without-gnutls )
+      try_gnutls=0
+    ;;
    --host-system=* )
      OPERATINGSYSTEM=`echo $option | sed -e 's/^.*=//;'`
    ;;
@@ -362,10 +433,11 @@ SYSTEM=${OPERATINGSYSTEM}-${MACHINE}

 case $OPERATINGSYSTEM in
    Linux)
-        EXTRA_OBJECTS="sys_generic.o sys_linux.o sys_timex.o"
+        EXTRA_OBJECTS="sys_generic.o sys_linux.o sys_timex.o sys_posix.o"
        [ $try_libcap != "0" ] && try_libcap=1
        try_rtc=1
        [ $try_seccomp != "0" ] && try_seccomp=1
+        try_timestamping=1
        try_setsched=1
        try_lockmem=1
        try_phc=1
@@ -373,7 +445,12 @@ case $OPERATINGSYSTEM in
        echo "Configuring for " $SYSTEM
    ;;
    FreeBSD)
-        EXTRA_OBJECTS="sys_generic.o sys_netbsd.o sys_timex.o"
+        # recvmmsg() seems to be broken on FreeBSD 11.0 and it's just
+        # a wrapper around recvmsg()
+        try_recvmmsg=0
+        EXTRA_OBJECTS="sys_generic.o sys_netbsd.o sys_timex.o sys_posix.o"
+        try_setsched=1
+        try_lockmem=1
        add_def FREEBSD
        if [ $feat_droproot = "1" ]; then
          add_def FEAT_PRIVDROP
@@ -382,26 +459,37 @@ case $OPERATINGSYSTEM in
        echo "Configuring for $SYSTEM"
    ;;
    NetBSD)
-        EXTRA_OBJECTS="sys_generic.o sys_netbsd.o sys_timex.o"
+        EXTRA_OBJECTS="sys_generic.o sys_netbsd.o sys_timex.o sys_posix.o"
        try_clockctl=1
+        try_setsched=1
+        try_lockmem=1
        add_def NETBSD
        echo "Configuring for $SYSTEM"
    ;;
    Darwin)
        EXTRA_OBJECTS="sys_macosx.o"
-        EXTRA_LIBS="-lresolv"
-        EXTRA_CLI_LIBS="-lresolv"
+        LIBS="$LIBS -lresolv"
        add_def MACOSX
        if [ $feat_droproot = "1" ]; then
          add_def FEAT_PRIVDROP
          priv_ops="ADJUSTTIME SETTIME BINDSOCKET"
        fi
-        echo "Configuring for MacOS X (" $SYSTEM "MacOS X version" $VERSION ")"
+        major=`echo $VERSION | cut -d. -f1`
+        # ntp_adjtime is not available in macOS 10.12 (Darwin 16.x.x) and earlier
+        if [ $major -gt "16" ]; then
+          add_def HAVE_MACOS_SYS_TIMEX
+          EXTRA_OBJECTS="$EXTRA_OBJECTS sys_generic.o sys_netbsd.o sys_timex.o"
+          if [ $feat_droproot = "1" ]; then
+            priv_ops="$priv_ops ADJUSTTIMEX"
+          fi
+        fi
+        echo "Configuring for macOS (" $SYSTEM "macOS version" $VERSION ")"
    ;;
    SunOS)
-        EXTRA_OBJECTS="sys_generic.o sys_solaris.o sys_timex.o"
-        EXTRA_LIBS="-lsocket -lnsl -lresolv"
-        EXTRA_CLI_LIBS="-lsocket -lnsl -lresolv"
+        EXTRA_OBJECTS="sys_generic.o sys_solaris.o sys_timex.o sys_posix.o"
+        LIBS="$LIBS -lsocket -lnsl -lresolv"
+        try_setsched=1
+        try_lockmem=1
        add_def SOLARIS
        # These are needed to have msg_control in struct msghdr
        add_def __EXTENSIONS__
@@ -431,9 +519,14 @@ fi

 if [ $feat_ntp = "1" ]; then
  add_def FEAT_NTP
-  EXTRA_OBJECTS="$EXTRA_OBJECTS ntp_core.o ntp_io.o ntp_sources.o"
+  EXTRA_OBJECTS="$EXTRA_OBJECTS ntp_auth.o ntp_core.o ntp_ext.o ntp_io.o ntp_sources.o"
+  if [ $feat_ntp_signd = "1" ]; then
+    add_def FEAT_SIGND
+    EXTRA_OBJECTS="$EXTRA_OBJECTS ntp_signd.o"
+  fi
 else
  feat_asyncdns=0
+  feat_timestamping=0
 fi

 if [ "$feat_cmdmon" = "1" ] || [ $feat_ntp = "1" ]; then
@@ -453,14 +546,16 @@ MYCPPFLAGS="$CPPFLAGS"
 MYLDFLAGS="$LDFLAGS"

 if [ "x$MYCC" = "x" ]; then
-  MYCC=gcc
-  if ! test_code "$MYCC" '' '' '' ''; then
-    MYCC=cc
-    if ! test_code "$MYCC" '' '' '' ''; then
+  for cc in gcc clang cc ""; do
+    if [ "x$cc" = "x" ]; then
      echo "error: no C compiler found"
      exit 1
    fi
-  fi
+    MYCC=$cc
+    if test_code "$MYCC" '' '' '' ''; then
+      break
+    fi
+  done
 else
  if ! test_code "$MYCC" '' '' '' ''; then
    echo "error: C compiler $MYCC cannot create executables"
@@ -470,12 +565,38 @@ fi

 if [ "x$MYCFLAGS" = "x" ]; then
  MYCFLAGS="-O2 -g"
+
+  TESTCFLAGS="-D_FORTIFY_SOURCE=2 -fPIE"
+  TESTLDFLAGS="-pie -Wl,-z,relro,-z,now"
+  if test_code 'hardening compiler options' '' "$TESTCFLAGS" "$TESTLDFLAGS" ''; then
+    MYCFLAGS="$MYCFLAGS $TESTCFLAGS"
+    MYLDFLAGS="$MYLDFLAGS $TESTLDFLAGS"
+  fi
+  TESTCFLAGS="-fstack-protector-strong --param=ssp-buffer-size=4"
+  if test_code '-fstack-protector-strong' '' "$TESTCFLAGS" '' ''; then
+    MYCFLAGS="$MYCFLAGS $TESTCFLAGS"
+  else
+    TESTCFLAGS="-fstack-protector --param=ssp-buffer-size=4"
+    if test_code '-fstack-protector' '' "$TESTCFLAGS" '' ''; then
+      MYCFLAGS="$MYCFLAGS $TESTCFLAGS"
+    fi
+  fi
 fi

-if [ "x$MYCC" = "xgcc" ]; then
+if [ "x$MYCC" = "xgcc" ] || [ "x$MYCC" = "xclang" ]; then
  MYCFLAGS="$MYCFLAGS -Wmissing-prototypes -Wall"
 fi

+if [ "x$PKG_CONFIG" = "x" ]; then
+  PKG_CONFIG=pkg-config
+fi
+
+if ! test_executable "pkg-config" $PKG_CONFIG --version; then
+  try_nettle=0
+  try_nss=0
+  try_gnutls=0
+fi
+
 if test_code '64-bit time_t' 'time.h' '' '' '
  char x[sizeof(time_t) > 4 ? 1 : -1] = {0};
  return x[0];'
@@ -486,7 +607,11 @@ then
    split_seconds=$ntp_era_split
    split_days=0
  else
-    split_seconds=`date '+%s'`
+    if [ "x$SOURCE_DATE_EPOCH" != "x" ]; then
+      split_seconds=$SOURCE_DATE_EPOCH
+    else
+      split_seconds=`date '+%s'`
+    fi
    if [ "x$split_seconds" = "x" ]; then
      echo "error: could not get current time, --with-ntp-era option is needed"
      exit 1
@@ -511,25 +636,15 @@ then
 fi

 MATHCODE='return (int) pow(2.0, log(sqrt((double)argc)));'
-if test_code 'math' 'math.h' '' '' "$MATHCODE"; then
-  LIBS=""
-else
+if ! test_code 'math' 'math.h' '' '' "$MATHCODE"; then
  if test_code 'math in -lm' 'math.h' '' '-lm' "$MATHCODE"; then
-    LIBS="-lm"
+    LIBS="$LIBS -lm"
  else
    echo "error: could not compile/link a program which uses sqrt(), log(), pow()"
    exit 1
  fi
 fi
  
-if test_code '<stdint.h>' 'stdint.h' '' '' ''; then
-  add_def HAVE_STDINT_H
-fi
-
-if test_code '<inttypes.h>' 'inttypes.h' '' '' ''; then
-  add_def HAVE_INTTYPES_H
-fi
-
 if test_code 'struct in_pktinfo' 'sys/socket.h netinet/in.h' '' '' '
  struct in_pktinfo ipi;
  return sizeof (ipi.ipi_spec_dst.s_addr) + IP_PKTINFO;'
@@ -538,7 +653,7 @@ then
 fi

 if [ $feat_ipv6 = "1" ] && \
-  test_code 'IPv6 support' 'arpa/inet.h sys/socket.h netinet/in.h' '' "$EXTRA_LIBS" '
+  test_code 'IPv6 support' 'arpa/inet.h sys/socket.h netinet/in.h' '' "$LIBS" '
    struct sockaddr_in6 n;
    char p[100];
    n.sin6_addr = in6addr_any;
@@ -559,33 +674,95 @@ then
  fi
 fi

-if test_code 'getaddrinfo()' 'sys/types.h sys/socket.h netdb.h' '' "$EXTRA_LIBS" \
+if [ $try_clock_gettime = "1" ]; then
+  if test_code 'clock_gettime()' 'time.h' '' '' \
+    'clock_gettime(CLOCK_REALTIME, NULL);'
+  then
+    add_def HAVE_CLOCK_GETTIME
+  else
+    if test_code 'clock_gettime() in -lrt' 'time.h' '' '-lrt' \
+      'clock_gettime(CLOCK_REALTIME, NULL);'
+    then
+      add_def HAVE_CLOCK_GETTIME
+      EXTRA_LIBS="$EXTRA_LIBS -lrt"
+    fi
+  fi
+fi
+
+if test_code 'getaddrinfo()' 'sys/types.h sys/socket.h netdb.h' '' "$LIBS" \
  'return getaddrinfo(0, 0, 0, 0);'
 then
  add_def HAVE_GETADDRINFO
 fi

 if [ $feat_asyncdns = "1" ] && \
-  test_code 'pthread' 'pthread.h' '-pthread' '' \
-    'return pthread_create((void *)1, NULL, (void *)1, NULL);'
+  test_code 'pthread' 'pthread.h' '-pthread' '' '
+    pthread_t thread;
+    return (int)pthread_create(&thread, NULL, (void *)1, NULL);'
 then
  add_def FEAT_ASYNCDNS
  add_def USE_PTHREAD_ASYNCDNS
  EXTRA_OBJECTS="$EXTRA_OBJECTS nameserv_async.o"
-  MYCFLAGS="$MYCFLAGS -pthread"
+  use_pthread=1
 fi

 if test_code 'arc4random_buf()' 'stdlib.h' '' '' 'arc4random_buf(NULL, 0);'; then
  add_def HAVE_ARC4RANDOM
 fi

+if test_code 'getrandom()' 'stdlib.h sys/random.h' '' '' \
+    'return getrandom(NULL, 256, 0);'; then
+  add_def HAVE_GETRANDOM
+fi
+
+RECVMMSG_CODE='
+  struct mmsghdr hdr;
+  return !recvmmsg(0, &hdr, 1, MSG_DONTWAIT, 0);'
+if [ $try_recvmmsg = "1" ]; then
+  if test_code 'recvmmsg()' 'sys/socket.h' '' "$LIBS" "$RECVMMSG_CODE"; then
+    add_def HAVE_RECVMMSG
+  else
+    if test_code 'recvmmsg() with _GNU_SOURCE' 'sys/socket.h' '-D_GNU_SOURCE' \
+      "$LIBS" "$RECVMMSG_CODE"
+    then
+      add_def _GNU_SOURCE
+      add_def HAVE_RECVMMSG
+    fi
+  fi
+fi
+
+if [ $feat_timestamping = "1" ] && [ $try_timestamping = "1" ] &&
+  test_code 'SW/HW timestamping' 'sys/types.h sys/socket.h linux/net_tstamp.h
+                                  linux/errqueue.h linux/ptp_clock.h' '' '' '
+    int val = SOF_TIMESTAMPING_SOFTWARE | SOF_TIMESTAMPING_RX_SOFTWARE |
+              SOF_TIMESTAMPING_RAW_HARDWARE | SOF_TIMESTAMPING_OPT_CMSG;
+    return sizeof (struct scm_timestamping) + SCM_TSTAMP_SND + PTP_SYS_OFFSET +
+           setsockopt(0, SOL_SOCKET, SO_SELECT_ERR_QUEUE + SO_TIMESTAMPING,
+                      &val, sizeof (val));'
+then
+  add_def HAVE_LINUX_TIMESTAMPING
+  EXTRA_OBJECTS="$EXTRA_OBJECTS hwclock.o ntp_io_linux.o"
+
+  if test_code 'other timestamping options' \
+    'sys/types.h sys/socket.h linux/net_tstamp.h' '' '' '
+    struct scm_ts_pktinfo pktinfo;
+    pktinfo.if_index = pktinfo.pkt_length = 0;
+    return pktinfo.if_index + pktinfo.pkt_length + HWTSTAMP_FILTER_NTP_ALL +
+           SCM_TIMESTAMPING_PKTINFO +
+           SOF_TIMESTAMPING_OPT_PKTINFO + SOF_TIMESTAMPING_OPT_TX_SWHW;'; then
+    add_def HAVE_LINUX_TIMESTAMPING_RXFILTER_NTP 1
+    add_def HAVE_LINUX_TIMESTAMPING_OPT_PKTINFO 1
+    add_def HAVE_LINUX_TIMESTAMPING_OPT_TX_SWHW 1
+  fi
+fi
+
 timepps_h=""
 if [ $feat_refclock = "1" ] && [ $feat_pps = "1" ]; then
-  if test_code '<sys/timepps.h>' 'sys/timepps.h' '' '' ''; then
+  if test_code '<sys/timepps.h>' 'inttypes.h time.h sys/timepps.h' '' '' ''; then
    timepps_h="sys/timepps.h"
    add_def HAVE_SYS_TIMEPPS_H
  else
-    if test_code '<timepps.h>' 'timepps.h' '' '' ''; then
+    if test_code '<timepps.h>' 'inttypes.h time.h timepps.h' '' '' ''; then
      timepps_h="timepps.h"
      add_def HAVE_TIMEPPS_H
    fi
@@ -593,10 +770,11 @@ if [ $feat_refclock = "1" ] && [ $feat_pps = "1" ]; then
 fi

 if [ "x$timepps_h" != "x" ] && \
-  test_code 'PPSAPI' "string.h $timepps_h" '' '' '
+  test_code 'PPSAPI' "inttypes.h string.h time.h $timepps_h" '' '' '
    pps_handle_t h = 0;
    pps_info_t i;
    struct timespec ts;
+    ts.tv_sec = ts.tv_nsec = 0;
    return time_pps_fetch(h, PPS_TSFMT_TSPEC, &i, &ts);'
 then
  add_def FEAT_PPS
@@ -628,7 +806,7 @@ then
  # NAME2IPADDRESS shouldn't be enabled with other operations as the helper
  # process works on one request at the time and the async resolver could
  # block the main thread
-  priv_ops="NAME2IPADDRESS"
+  priv_ops="NAME2IPADDRESS RELOADDNS"
  EXTRA_LIBS="$EXTRA_LIBS -lseccomp"
 fi

@@ -649,49 +827,51 @@ then
 fi

 if [ $feat_refclock = "1" ] && [ $feat_phc = "1" ] && [ $try_phc = "1" ] && \
+  grep '#define HAVE_CLOCK_GETTIME' config.h > /dev/null && \
  test_code '<linux/ptp_clock.h>' 'sys/ioctl.h linux/ptp_clock.h' '' '' \
-    'ioctl(1, PTP_CLOCK_GETCAPS, 0);'
+    'ioctl(1, PTP_CLOCK_GETCAPS + PTP_SYS_OFFSET, 0);'
 then
-  if test_code 'clock_gettime()' 'time.h' '' '' 'clock_gettime(0, NULL);'; then
-    add_def FEAT_PHC
-  else
-    if test_code 'clock_gettime() in -lrt' 'time.h' '' '-lrt' \
-      'clock_gettime(0, NULL);'
-    then
-      EXTRA_LIBS="$EXTRA_LIBS -lrt"
-      add_def FEAT_PHC
-    fi
-  fi
+  grep 'HAVE_LINUX_TIMESTAMPING' config.h > /dev/null ||
+    EXTRA_OBJECTS="$EXTRA_OBJECTS hwclock.o"
+  add_def FEAT_PHC
 fi

 if [ $try_setsched = "1" ] && \
  test_code \
-    'sched_setscheduler()' \
-    'sched.h' '' '' '
+    'pthread_setschedparam()' \
+    'pthread.h sched.h' '-pthread' '' '
     struct sched_param sched;
     sched_get_priority_max(SCHED_FIFO);
-     sched_setscheduler(0, SCHED_FIFO, &sched);'
+     pthread_setschedparam(pthread_self(), SCHED_FIFO, &sched);'
 then
-  add_def HAVE_SCHED_SETSCHEDULER
+  add_def HAVE_PTHREAD_SETSCHEDPARAM
+  use_pthread=1
 fi

 if [ $try_lockmem = "1" ] && \
  test_code \
    'mlockall()' \
-    'sys/mman.h sys/resource.h' '' '' '
-     struct rlimit rlim;
-     setrlimit(RLIMIT_MEMLOCK, &rlim);
+    'sys/mman.h' '' '' '
     mlockall(MCL_CURRENT|MCL_FUTURE);'
 then
  add_def HAVE_MLOCKALL
 fi
+if [ $try_lockmem = "1" ] && \
+  test_code \
+    'setrlimit(RLIMIT_MEMLOCK, ...)' \
+    'sys/resource.h' '' '' '
+     struct rlimit rlim;
+     rlim.rlim_max = rlim.rlim_cur = RLIM_INFINITY;
+     setrlimit(RLIMIT_MEMLOCK, &rlim);'
+then
+  add_def HAVE_SETRLIMIT_MEMLOCK
+fi

 if [ $feat_forcednsretry = "1" ]
 then
  add_def FORCE_DNSRETRY
 fi

-READLINE_COMPILE=""
 READLINE_LINK=""
 if [ $feat_readline = "1" ]; then
  if [ $try_editline = "1" ]; then
@@ -701,7 +881,7 @@ if [ $feat_readline = "1" ]; then
    then
      add_def FEAT_READLINE
      add_def USE_EDITLINE
-      READLINE_COMPILE="$readline_inc"
+      MYCPPFLAGS="$MYCPPFLAGS $readline_inc"
      READLINE_LINK="$readline_lib -ledit"
    fi
  fi
@@ -712,7 +892,7 @@ if [ $feat_readline = "1" ]; then
      'add_history(readline("prompt"));'
    then
      add_def FEAT_READLINE
-      READLINE_COMPILE="$readline_inc"
+      MYCPPFLAGS="$MYCPPFLAGS $readline_inc"
      READLINE_LINK="$readline_lib -lreadline"
    fi
  fi
@@ -724,7 +904,7 @@ if [ $feat_readline = "1" ]; then
      'add_history(readline("prompt"));'
    then
      add_def FEAT_READLINE
-      READLINE_COMPILE="$readline_inc"
+      MYCPPFLAGS="$MYCPPFLAGS $readline_inc"
      READLINE_LINK="$readline_lib $ncurses_lib -lreadline -lncurses"
    fi
  fi
@@ -733,10 +913,31 @@ if [ $feat_readline = "1" ]; then
 fi

 HASH_OBJ="hash_intmd5.o"
-HASH_COMPILE=""
 HASH_LINK=""

-if [ $feat_sechash = "1" ] && [ $try_nss = "1" ]; then
+if [ $feat_sechash = "1" ] && [ "x$HASH_LINK" = "x" ]  && [ $try_nettle = "1" ]; then
+  test_cflags="`pkg_config --cflags nettle`"
+  test_link="`pkg_config --libs nettle`"
+  if test_code 'nettle' 'nettle/nettle-meta.h nettle/sha2.h' \
+    "$test_cflags" "$test_link" \
+    'return nettle_hashes[0]->context_size;'
+  then
+    HASH_OBJ="hash_nettle.o"
+    HASH_LINK="$test_link"
+    MYCPPFLAGS="$MYCPPFLAGS $test_cflags"
+    add_def FEAT_SECHASH
+
+    if test_code 'CMAC in nettle' 'nettle/cmac.h' "$test_cflags" "$test_link" \
+      'cmac128_update(NULL, NULL, NULL, 0, NULL);'
+    then
+      add_def HAVE_CMAC
+      EXTRA_OBJECTS="$EXTRA_OBJECTS cmac_nettle.o"
+      EXTRA_CLI_OBJECTS="$EXTRA_CLI_OBJECTS cmac_nettle.o"
+    fi
+  fi
+fi
+
+if [ $feat_sechash = "1" ] && [ "x$HASH_LINK" = "x" ]  && [ $try_nss = "1" ]; then
  test_cflags="`pkg_config --cflags nss`"
  test_link="`pkg_config --libs-only-L nss` -lfreebl3"
  if test_code 'NSS' 'nss.h hasht.h nsslowhash.h' \
@@ -744,9 +945,8 @@ if [ $feat_sechash = "1" ] && [ $try_nss = "1" ]; then
    'NSSLOWHASH_Begin(NSSLOWHASH_NewContext(NSSLOW_Init(), HASH_AlgSHA512));'
  then
    HASH_OBJ="hash_nss.o"
-    HASH_COMPILE="$test_cflags"
    HASH_LINK="$test_link"
-    LIBS="$LIBS $HASH_LINK"
+    MYCPPFLAGS="$MYCPPFLAGS $test_cflags"
    add_def FEAT_SECHASH
  fi
 fi
@@ -756,13 +956,49 @@ if [ $feat_sechash = "1" ] && [ "x$HASH_LINK" = "x" ] && [ $try_tomcrypt = "1" ]
    'hash_memory_multi(find_hash("md5"), NULL, NULL, NULL, 0, NULL, 0);'
  then
    HASH_OBJ="hash_tomcrypt.o"
-    HASH_COMPILE="-I/usr/include/tomcrypt"
    HASH_LINK="-ltomcrypt"
-    LIBS="$LIBS $HASH_LINK"
+    MYCPPFLAGS="$MYCPPFLAGS -I/usr/include/tomcrypt"
    add_def FEAT_SECHASH
  fi
 fi

+EXTRA_OBJECTS="$EXTRA_OBJECTS $HASH_OBJ"
+EXTRA_CLI_OBJECTS="$EXTRA_CLI_OBJECTS $HASH_OBJ"
+LIBS="$LIBS $HASH_LINK"
+
+if [ $feat_ntp = "1" ] && [ $feat_nts = "1" ] && [ $try_gnutls = "1" ] && \
+    echo "$HASH_LINK" | grep 'nettle' > /dev/null; then
+  test_cflags="`pkg_config --cflags gnutls`"
+  test_link="`pkg_config --libs gnutls`"
+  if test_code 'gnutls' 'gnutls/gnutls.h' \
+    "$test_cflags" "$test_link" '
+      return gnutls_init(NULL, 0) +
+        gnutls_priority_init2(NULL, "", NULL, GNUTLS_PRIORITY_INIT_DEF_APPEND) +
+        gnutls_prf_rfc5705(NULL, 0, "", 0, "", 16, NULL);' &&
+    test_code 'AES128 in nettle' 'nettle/aes.h' '' "$LIBS" \
+      'aes128_set_encrypt_key(NULL, NULL);'
+  then
+    EXTRA_OBJECTS="$EXTRA_OBJECTS nts_ke_client.o nts_ke_server.o nts_ke_session.o"
+    EXTRA_OBJECTS="$EXTRA_OBJECTS nts_ntp_auth.o nts_ntp_client.o nts_ntp_server.o"
+    EXTRA_OBJECTS="$EXTRA_OBJECTS siv_nettle.o"
+    LIBS="$LIBS $test_link"
+    MYCPPFLAGS="$MYCPPFLAGS $test_cflags"
+    add_def FEAT_NTS
+
+    add_def HAVE_SIV
+    if test_code 'SIV in nettle' \
+      'nettle/siv-cmac.h' "" "$LIBS" \
+      'siv_cmac_aes128_set_key(NULL, NULL);'
+    then
+      add_def HAVE_NETTLE_SIV_CMAC
+    fi
+  fi
+fi
+
+if [ $use_pthread = "1" ]; then
+  MYCFLAGS="$MYCFLAGS -pthread"
+fi
+
 SYSCONFDIR=/etc
 if [ "x$SETSYSCONFDIR" != "x" ]; then
  SYSCONFDIR=$SETSYSCONFDIR
@@ -808,9 +1044,9 @@ if [ "x$SETLOCALSTATEDIR" != "x" ]; then
  LOCALSTATEDIR=$SETLOCALSTATEDIR
 fi

-CHRONYSOCKDIR=${LOCALSTATEDIR}/run/chrony
-if [ "x$SETCHRONYSOCKDIR" != "x" ]; then
-  CHRONYSOCKDIR=$SETCHRONYSOCKDIR
+CHRONYRUNDIR=${LOCALSTATEDIR}/run/chrony
+if [ "x$SETCHRONYRUNDIR" != "x" ]; then
+  CHRONYRUNDIR=$SETCHRONYRUNDIR
 fi

 CHRONYVARDIR=${LOCALSTATEDIR}/lib/chrony
@@ -820,13 +1056,15 @@ fi

 add_def DEFAULT_CONF_FILE "\"$SYSCONFDIR/chrony.conf\""
 add_def DEFAULT_HWCLOCK_FILE "\"$default_hwclockfile\""
+add_def DEFAULT_PID_FILE "\"$default_pidfile\""
+add_def DEFAULT_RTC_DEVICE "\"$default_rtcdevice\""
 add_def DEFAULT_USER "\"$default_user\""
-add_def DEFAULT_COMMAND_SOCKET "\"$CHRONYSOCKDIR/chronyd.sock\""
+add_def DEFAULT_COMMAND_SOCKET "\"$CHRONYRUNDIR/chronyd.sock\""
 add_def MAIL_PROGRAM "\"$mail_program\""

-common_features="`get_features IPV6 DEBUG`"
+common_features="`get_features SECHASH IPV6 DEBUG`"
 chronyc_features="`get_features READLINE`"
-chronyd_features="`get_features CMDMON NTP REFCLOCK RTC PRIVDROP SCFILTER SECHASH ASYNCDNS`"
+chronyd_features="`get_features CMDMON NTP REFCLOCK RTC PRIVDROP SCFILTER SIGND ASYNCDNS NTS`"
 add_def CHRONYC_FEATURES "\"$chronyc_features $common_features\""
 add_def CHRONYD_FEATURES "\"$chronyd_features $common_features\""
 echo "Features : $chronyd_features $chronyc_features $common_features"
@@ -842,26 +1080,26 @@ add_def CHRONY_VERSION "\"${CHRONY_VERSION}\""
 for f in Makefile doc/Makefile test/unit/Makefile
 do
  echo Creating $f
-  sed -e "s%@EXTRA_OBJECTS@%${EXTRA_OBJECTS}%;\
+  sed -e "s%@EXTRA_OBJS@%${EXTRA_OBJECTS}%;\
+          s%@EXTRA_CLI_OBJS@%${EXTRA_CLI_OBJECTS}%;\
          s%@CC@%${MYCC}%;\
          s%@CFLAGS@%${MYCFLAGS}%;\
          s%@CPPFLAGS@%${MYCPPFLAGS}%;\
-          s%@LIBS@%${LIBS}%;\
          s%@LDFLAGS@%${MYLDFLAGS}%;\
+          s%@LIBS@%${LIBS}%;\
          s%@EXTRA_LIBS@%${EXTRA_LIBS}%;\
          s%@EXTRA_CLI_LIBS@%${EXTRA_CLI_LIBS}%;\
-          s%@READLINE_COMPILE@%${READLINE_COMPILE}%;\
-          s%@HASH_OBJ@%${HASH_OBJ}%;\
-          s%@HASH_COMPILE@%${HASH_COMPILE}%;\
          s%@SYSCONFDIR@%${SYSCONFDIR}%;\
          s%@BINDIR@%${BINDIR}%;\
          s%@SBINDIR@%${SBINDIR}%;\
          s%@DOCDIR@%${DOCDIR}%;\
          s%@MANDIR@%${MANDIR}%;\
          s%@LOCALSTATEDIR@%${LOCALSTATEDIR}%;\
-          s%@CHRONYSOCKDIR@%${CHRONYSOCKDIR}%;\
+          s%@CHRONYRUNDIR@%${CHRONYRUNDIR}%;\
          s%@CHRONYVARDIR@%${CHRONYVARDIR}%;\
          s%@DEFAULT_HWCLOCK_FILE@%${default_hwclockfile}%;\
+          s%@DEFAULT_PID_FILE@%${default_pidfile}%;\
+          s%@DEFAULT_RTC_DEVICE@%${default_rtcdevice}%;\
          s%@DEFAULT_USER@%${default_user}%;\
          s%@CHRONY_VERSION@%${CHRONY_VERSION}%;" \
          < ${f}.in > $f
--- a/contrib/bryan_christianson_1/README.txt
+++ b/contrib/bryan_christianson_1/README.txt
@@ -1,16 +1,16 @@
-Notes for installing chrony on MacOS X
+Notes for installing chrony on macOS
 Author: Bryan Christianson (bryan@whatroute.net)
 ------------------------------------------------

 These files are for those admins/users who would prefer to install chrony
 from the source distribution and are intended as guidelines rather than
 being definitive. They can be edited with a plain text editor, such as
-vi, emacs or your favourite IDE (xcode)
+vi, emacs or your favourite IDE (Xcode)

 It is assumed you are comfortable with installing software from the
 terminal command line and know how to use sudo to acquire root access.

-If you are not familiar with the MacOS X command line then
+If you are not familiar with the macOS command line then
 please consider using ChronyControl from http://whatroute.net/chronycontrol.html

 ChronyControl provides a gui wrapper for installing these files and sets the
@@ -72,7 +72,7 @@ Installing the support files

 1. chronylogrotate.sh
 This is a simple shell script that deletes old log files. Unfortunately because
-of the need to run chronyc, the standard MacOS X logrotation does not work with
+of the need to run chronyc, the standard macOS logrotation does not work with
 chrony logs.

 This script runs on a daily basis under control of launchd and should be
--- a/doc/Makefile.in
+++ b/doc/Makefile.in
@@ -13,19 +13,23 @@ BINDIR = @BINDIR@
 SBINDIR = @SBINDIR@
 MANDIR = @MANDIR@
 DOCDIR = @DOCDIR@
-CHRONYSOCKDIR = @CHRONYSOCKDIR@
+CHRONYRUNDIR = @CHRONYRUNDIR@
 CHRONYVARDIR = @CHRONYVARDIR@
 CHRONY_VERSION = @CHRONY_VERSION@
 DEFAULT_USER = @DEFAULT_USER@
 DEFAULT_HWCLOCK_FILE = @DEFAULT_HWCLOCK_FILE@
+DEFAULT_PID_FILE = @DEFAULT_PID_FILE@
+DEFAULT_RTC_DEVICE = @DEFAULT_RTC_DEVICE@

 SED_COMMANDS = "s%\@SYSCONFDIR\@%$(SYSCONFDIR)%g;\
 	       s%\@BINDIR\@%$(BINDIR)%g;\
 	       s%\@SBINDIR\@%$(SBINDIR)%g;\
 	       s%\@CHRONY_VERSION\@%$(CHRONY_VERSION)%g;\
 	       s%\@DEFAULT_HWCLOCK_FILE\@%$(DEFAULT_HWCLOCK_FILE)%g;\
+	       s%\@DEFAULT_PID_FILE\@%$(DEFAULT_PID_FILE)%g;\
+	       s%\@DEFAULT_RTC_DEVICE\@%$(DEFAULT_RTC_DEVICE)%g;\
 	       s%\@DEFAULT_USER\@%$(DEFAULT_USER)%g;\
-	       s%\@CHRONYSOCKDIR\@%$(CHRONYSOCKDIR)%g;\
+	       s%\@CHRONYRUNDIR\@%$(CHRONYRUNDIR)%g;\
 	       s%\@CHRONYVARDIR\@%$(CHRONYVARDIR)%g;"

 man: $(MAN_FILES) $(MAN_IN_FILES)
--- a/doc/chrony.conf.adoc
+++ b/doc/chrony.conf.adoc
--- a/doc/chronyc.adoc
+++ b/doc/chronyc.adoc
@@ -1,7 +1,8 @@
 // This file is part of chrony
 //
 // Copyright (C) Richard P. Curnow  1997-2003
-// Copyright (C) Miroslav Lichvar  2009-2016
+// Copyright (C) Stephen Wadeley  2016
+// Copyright (C) Miroslav Lichvar  2009-2017
 //
 // This program is free software; you can redistribute it and/or modify
 // it under the terms of version 2 of the GNU General Public License as
@@ -44,7 +45,7 @@ There are two ways *chronyc* can access *chronyd*. One is the Internet
 Protocol (IPv4 or IPv6) and the other is a Unix domain socket, which is
 accessible locally by the root or _chrony_ user. By default, *chronyc* first
 tries to connect to the Unix domain socket. The compiled-in default path is
-_@CHRONYSOCKDIR@/chronyd.sock_. If that fails (e.g. because *chronyc* is
+_@CHRONYRUNDIR@/chronyd.sock_. If that fails (e.g. because *chronyc* is
 running under a non-root user), it will try to connect to 127.0.0.1 and then
 ::1.

@@ -74,14 +75,21 @@ With this option hostnames will be resolved only to IPv4 addresses.
 With this option hostnames will be resolved only to IPv6 addresses.

 *-n*::
-This option disables resolving of IP addresses to hostnames (e.g. to avoid slow
-DNS lookups).
+This option disables resolving of IP addresses to hostnames, e.g. to avoid slow
+DNS lookups. Long addresses will not be truncated to fit into the column.
+
+*-N*::
+This option enables printing of the original names of NTP sources that were
+specified in the configuration file, or *chronyc* commands, and are internally
+used by *chronyd*. Without the *-n* and *-N* option, the names of NTP sources
+are obtained from reverse DNS lookups and can be different from the original
+names.

 *-c*::
 This option enables printing of reports in a comma-separated values (CSV)
-format. IP addresses will not be resolved to hostnames, time will be printed as
-number of seconds since the epoch and values in seconds will not be converted
-to other units.
+format. Reverse DNS lookups will be disabled, time will be printed as number of
+seconds since the epoch, and values in seconds will not be converted to other
+units.

 *-d*::
 This option enables printing of debugging messages if *chronyc* was compiled
@@ -127,17 +135,17 @@ The *tracking* command displays parameters about the system's clock
 performance. An example of the output is shown below.
 +
 ----
-Reference ID    : 203.0.113.15 (foo.example.net)
+Reference ID    : CB00710F (foo.example.net)
 Stratum         : 3
-Ref time (UTC)  : Fri Feb  3 15:00:29 2012
-System time     : 0.000001501 seconds slow of NTP time
-Last offset     : -0.000001632 seconds
-RMS offset      : 0.000002360 seconds
-Frequency       : 331.898 ppm fast
-Residual freq   : 0.004 ppm
-Skew            : 0.154 ppm
-Root delay      : 0.373169 seconds
-Root dispersion : 0.024780 seconds
+Ref time (UTC)  : Fri Jan 27 09:49:17 2017
+System time     : 0.000006523 seconds slow of NTP time
+Last offset     : -0.000006747 seconds
+RMS offset      : 0.000035822 seconds
+Frequency       : 3.225 ppm slow
+Residual freq   : -0.000 ppm
+Skew            : 0.129 ppm
+Root delay      : 0.013639022 seconds
+Root dispersion : 0.001100737 seconds
 Update interval : 64.2 seconds
 Leap status     : Normal
 ----
@@ -150,10 +158,14 @@ computer is currently synchronised. For IPv4 addresses, the reference ID is
 equal to the address and for IPv6 addresses it is the first 32 bits of the MD5
 sum of the address.
 +
-If it is _127.127.1.1_ it means the computer is not synchronised to any
-external source and that you have the _local_ mode operating (via the
-<<local,*local*>> command in *chronyc*, or the
+If the reference ID is _7F7F0101_ and there is no name or IP address, it means
+the computer is not synchronised to any external source and that you have the
+_local_ mode operating (via the <<local,*local*>> command in *chronyc*, or the
 <<chrony.conf.adoc#local,*local*>> directive in the configuration file).
+
+The reference ID is printed as a hexadecimal number. Note that in older
+versions it used to be printed in quad-dotted notation and could be confused
+with an IPv4 address.
 *Stratum*:::
 The stratum indicates how many hops away from a computer with an attached
 reference clock we are. Such a computer is a stratum-1 computer, so the
@@ -182,9 +194,6 @@ The '`frequency`' is the rate by which the system's clock would be wrong if
 For example, a value of 1 ppm would mean that when the system's clock thinks it
 has advanced 1 second, it has actually advanced by 1.000001 seconds relative to
 true time.
-+
-As you can see in the example, the clock in the computer is not a very
-good one; it would gain about 30 seconds per day if it was not corrected!
 *Residual freq*:::
 This shows the '`residual frequency`' for the currently selected reference
 source. This reflects any difference between what the measurements from the
@@ -214,7 +223,7 @@ An absolute bound on the computer's clock accuracy (assuming the stratum-1
 computer is correct) is given by:
 +
 ----
-clock_error <= root_dispersion + (0.5 * |root_delay|)
+clock_error <= |system_time_offset| + root_dispersion + (0.5 * root_delay)
 ----
 *Update interval*:::
 This is the interval between the last two clock updates.
@@ -282,15 +291,18 @@ milliseconds.

 === Time sources

-[[sources]]*sources* [*-v*]::
+[[sources]]*sources* [*-a*] [*-v*]::
 This command displays information about the current time sources that *chronyd*
 is accessing.
 +
-The optional argument *-v* can be specified, meaning _verbose_. In this case,
+If the *-a* option is specified, all sources are displayed, including those that
+do not have a known address yet. Such sources have an identifier in the format
+_ID#XXXXXXXXXX_, which can be used in other commands expecting a source address.
+
+The *-v* option enables a verbose output. In this case,
 extra caption lines are shown as a reminder of the meanings of the columns.
 +
 ----
-210 Number of sources = 3
 MS Name/IP address         Stratum Poll Reach LastRx Last sample
 ===============================================================================
 #* GPS0                          0   4   377    11   -479ns[ -621ns] +/-  134ns
@@ -336,8 +348,9 @@ register has 8 bits and is updated on every received or missed packet from
 the source. A value of 377 indicates that a valid reply was received for all
 from the last eight transmissions.
 *LastRx*:::
-This column shows how long ago the last sample was received from the source.
-This is normally in seconds. The letters _m_, _h_, _d_ or _y_ indicate
+This column shows how long ago the last good sample (which is shown in the next
+column) was received from the source. Measurements that failed some tests are
+ignored. This is normally in seconds. The letters _m_, _h_, _d_ or _y_ indicate
 minutes, hours, days, or years.
 *Last sample*:::
 This column shows the offset between the local clock and the source at the
@@ -350,18 +363,21 @@ since. The number following the _+/-_ indicator shows the margin of error in
 the measurement. Positive offsets indicate that the local clock is ahead of
 the source.

-[[sourcestats]]*sourcestats* [*-v*]::
+[[sourcestats]]*sourcestats* [*-a*] [*-v*]::
 The *sourcestats* command displays information about the drift rate and offset
 estimation process for each of the sources currently being examined by
 *chronyd*.
 +
-The optional argument *-v* can be specified, meaning _verbose_. In this case,
+If the *-a* option is specified, all sources are displayed, including those that
+do not have a known address yet. Such sources have an identifier in the format
+_ID#XXXXXXXXXX_, which can be used in other commands expecting a source address.
+
+The *-v* option enables a verbose output. In this case,
 extra caption lines are shown as a reminder of the meanings of the columns.
 +
 An example report is:
 +
 ----
-210 Number of sources = 1
 Name/IP Address            NP  NR  Span  Frequency  Freq Skew  Offset  Std Dev
 ===============================================================================
 foo.example.net            11   5   46m     -0.001      0.045      1us    25us
@@ -437,15 +453,100 @@ the offline state.
 the name of the server or peer was not resolved to an address yet; this source is
 not visible in the *sources* and *sourcestats* reports.

-[[add_peer]]*add peer* _address_ [_option_]...::
+[[ntpdata]]*ntpdata* [_address_]::
+The *ntpdata* command displays the last valid measurement and other
+NTP-specific information about the specified NTP source, or all NTP sources
+(with a known address) if no address was specified. An example of the output is
+shown below.
+
+----
+Remote address  : 203.0.113.15 (CB00710F)
+Remote port     : 123
+Local address   : 203.0.113.74 (CB00714A)
+Leap status     : Normal
+Version         : 4
+Mode            : Server
+Stratum         : 1
+Poll interval   : 10 (1024 seconds)
+Precision       : -24 (0.000000060 seconds)
+Root delay      : 0.000015 seconds
+Root dispersion : 0.000015 seconds
+Reference ID    : 47505300 (GPS)
+Reference time  : Fri Nov 25 15:22:12 2016
+Offset          : -0.000060878 seconds
+Peer delay      : 0.000175634 seconds
+Peer dispersion : 0.000000681 seconds
+Response time   : 0.000053050 seconds
+Jitter asymmetry: +0.00
+NTP tests       : 111 111 1111
+Interleaved     : No
+Authenticated   : No
+TX timestamping : Kernel
+RX timestamping : Kernel
+Total TX        : 24
+Total RX        : 24
+Total valid RX  : 24
+----
+
+The fields are explained as follows:
+
+*Remote address*:::
+The IP address of the NTP server or peer, and the corresponding reference ID.
+*Remote port*:::
+The UDP port number to which the request was sent. The standard NTP port is
+123.
+*Local address*:::
+The local IP address which received the response, and the corresponding
+reference ID.
+*Leap status*:::
+*Version*:::
+*Mode*:::
+*Stratum*:::
+*Poll interval*:::
+*Precision*:::
+*Root delay*:::
+*Root dispersion*:::
+*Reference ID*:::
+*Reference time*:::
+The NTP values from the last valid response.
+*Offset*:::
+*Peer delay*:::
+*Peer dispersion*:::
+The measured values.
+*Response time*:::
+The time the server or peer spent in processing of the request and waiting
+before sending the response.
+*Jitter asymmetry*:::
+The estimated asymmetry of network jitter on the path to the source. The
+asymmetry can be between -0.5 and 0.5. A negative value means the delay of
+packets sent to the source is more variable than the delay of packets sent
+from the source back.
+*NTP tests*:::
+Results of RFC 5905 tests 1 through 3, 5 through 7, and tests for maximum
+delay, delay ratio, delay dev ratio, and synchronisation loop.
+*Interleaved*:::
+This shows if the response was in the interleaved mode.
+*Authenticated*:::
+This shows if the response was authenticated.
+*TX timestamping*:::
+The source of the local transmit timestamp. Valid values are _Daemon_,
+_Kernel_, and _Hardware_.
+*RX timestamping*:::
+The source of the local receive timestamp.
+*Total TX*:::
+The number of packets sent to the source.
+*Total RX*:::
+The number of all packets received from the source.
+*Total valid RX*:::
+The number of valid packets received from the source.
+
+[[add_peer]]*add peer* _name_ [_option_]...::
 The *add peer* command allows a new NTP peer to be added whilst
 *chronyd* is running.
 +
 Following the words *add peer*, the syntax of the following
-parameters and options is similar to that for the
+parameters and options is identical to that for the
 <<chrony.conf.adoc#peer,*peer*>> directive in the configuration file.
-The following peer options can be set in the command: *port*, *minpoll*,
-*maxpoll*, *presend*, *maxdelayratio*, *maxdelay*, *key*.
 +
 An example of using this command is shown below.
 +
@@ -453,15 +554,27 @@ An example of using this command is shown below.
 add peer foo.example.net minpoll 6 maxpoll 10 key 25
 ----

-[[add_server]]*add server* _address_ [_option_]...::
+[[add_pool]]*add pool* _name_ [_option_]...::
+The *add pool* command allows a pool of NTP servers to be added whilst
+*chronyd* is running.
+
+Following the words *add pool*, the syntax of the following parameters and
+options is identical to that for the <<chrony.conf.adoc#pool,*pool*>>
+directive in the configuration file.
+
+An example of using this command is shown below:
+
+----
+add pool foo.example.net maxsources 3 iburst
+----
+
+[[add_server]]*add server* _name_ [_option_]...::
 The *add server* command allows a new NTP server to be added whilst
 *chronyd* is running.
 +
 Following the words *add server*, the syntax of the following parameters and
-options is similar to that for the <<chrony.conf.adoc#server,*server*>>
+options is identical to that for the <<chrony.conf.adoc#server,*server*>>
 directive in the configuration file.
-The following server options can be set in the command: *port*, *minpoll*,
-*maxpoll*, *presend*, *maxdelayratio*, *maxdelay*, *key*.
 +
 An example of using this command is shown below:
 +
@@ -599,7 +712,8 @@ the loaded periods. The *offline* and *online* commands can be used to achieve
 this.
 +
 There are four forms of the *offline* command. The first form is a wildcard,
-meaning all sources. The second form allows an IP address mask and a masked
+meaning all sources (including sources that do not have a known address yet).
+The second form allows an IP address mask and a masked
 address to be specified. The third form uses CIDR notation. The fourth form
 uses an IP address or a hostname. These forms are illustrated below.
 +
@@ -634,6 +748,14 @@ particular source or sources has been restored.
 +
 The syntax is identical to that of the <<offline,*offline*>> command.

+[[onoffline]]
+*onoffline*::
+The *onoffline* command tells *chronyd* to switch all sources that have a known
+address to the online or
+offline status according to the current network configuration. A source is
+considered online if it is possible to send requests to it, i.e. a network
+route to the source is present.
+
 [[polltarget]]*polltarget* _address_ _polltarget_::
 The *polltarget* command is used to modify the poll target for one of the
 current set of sources. It is equivalent to the *polltarget* option in the
@@ -648,6 +770,15 @@ Sources that stop responding will be replaced with newly resolved addresses
 automatically after 8 polling intervals, but this command can still be useful
 to replace them immediately and not wait until they are marked as unreachable.

+[[sourcename]]*sourcename* _address_::
+The *sourcename* command prints the original hostname or address that was
+specified for an NTP source in the configuration file, or the *add* command.
+This command is an alternative to the *-N* option, which can be useful in
+scripts.
+
+Note that different NTP sources can share the same name, e.g. servers from a
+pool.
+
 === Manual time input

 [[manual]]
@@ -1030,17 +1161,26 @@ purged. An example of how to do this is shown below.

 [[dump]]*dump*::
 The *dump* command causes *chronyd* to write its current history of
-measurements for each of its sources to dump files, either for inspection or to
-support the *-r* option when *chronyd* is restarted.
-+
-The *dump* command is somewhat equivalent to the
-<<chrony.conf.adoc#dumponexit,*dumponexit*>> directive in the configuration
-file.
-+
-To use the *dump* command, you might want to configure the name of the
-directory into which the dump files will be written. This can only be
-done in the configuration file with the <<chrony.conf.adoc#dumpdir,*dumpdir*>>
-directive.
+measurements for each of its sources to dump files in the directory specified
+in the configuration file by the <<chrony.conf.adoc#dumpdir,*dumpdir*>>
+directive. Note that *chronyd* does this automatically when it exits. This
+command is mainly useful for inspection of the history whilst *chronyd* is
+running.
+
+[[rekey]]*rekey*::
+The *rekey* command causes *chronyd* to re-read the key file specified in the
+configuration file by the <<chrony.conf.adoc#keyfile,*keyfile*>> directive.
+
+[[reset]]*reset*::
+The *reset* command causes *chronyd* to drop all measurements and switch to the
+unsynchronised state. This command can help *chronyd* with recovery when the
+measurements are known to be no longer valid or accurate, e.g. due to moving
+the computer to a different network, or resuming the computer from a low-power
+state (which resets the system clock).
+
+[[shutdown]]*shutdown*::
+The *shutdown* command causes *chronyd* to exit. This is equivalent to sending
+the process the SIGTERM signal.

 === Client commands

@@ -1090,10 +1230,10 @@ generated from the _/dev/urandom_ device and it is printed to standard output.
 +
 The command has three optional arguments. The first argument is the key number
 (by default 1), which will be specified with the *key* option of the *server*
-or *peer* directives in the configuration file. The second argument is the hash
-function (by default SHA1 or MD5 if SHA1 is not available) and the third
-argument is the number of bits the key should have, between 80 and 4096 bits
-(by default 160 bits).
+or *peer* directives in the configuration file. The second argument is the name
+of the hash function or cipher (by default SHA1, or MD5 if SHA1 is not
+available). The third argument is the length of the key in bits if a hash
+function was selected, between 80 and 4096 bits (by default 160 bits).
 +
 An example is:
 +
--- a/doc/chronyd.adoc
+++ b/doc/chronyd.adoc
@@ -1,7 +1,7 @@
 // This file is part of chrony
 //
 // Copyright (C) Richard P. Curnow  1997-2003
-// Copyright (C) Miroslav Lichvar  2009-2016
+// Copyright (C) Miroslav Lichvar  2009-2017
 //
 // This program is free software; you can redistribute it and/or modify
 // it under the terms of version 2 of the GNU General Public License as
@@ -41,7 +41,7 @@ If no configuration directives are specified on the command line, *chronyd*
 will read them from a configuration file. The compiled-in default location of
 the file is _@SYSCONFDIR@/chrony.conf_.

-Information messages and warnings will be logged to syslog.
+Informational messages, warnings, and errors will be logged to syslog.

 == OPTIONS

@@ -55,34 +55,46 @@ IPv6 sockets will be created.

 *-f* _file_::
 This option can be used to specify an alternate location for the configuration
-file (default _@SYSCONFDIR@/chrony.conf_).
+file. The default value is _@SYSCONFDIR@/chrony.conf_.

 *-n*::
 When run in this mode, the program will not detach itself from the terminal.

 *-d*::
 When run in this mode, the program will not detach itself from the terminal,
-and all messages will be sent to the terminal instead of to syslog. When
-*chronyd* was compiled with debugging support, this option can be used twice to
-print also debugging messages.
+and all messages will be written to the terminal instead of syslog. If
+*chronyd* was compiled with enabled support for debugging, this option can be
+used twice to enable debug messages.
+
+*-l* _file_::
+This option enables writing of log messages to a file instead of syslog or the
+terminal.
+
+*-L* _level_::
+This option specifies the minimum severity level of messages to be written to
+the log file, syslog, or terminal. The following levels can be specified:
+0 (informational), 1 (warning), 2 (non-fatal error), and 3 (fatal error). The
+default value is 0.

 *-q*::
 When run in this mode, *chronyd* will set the system clock once and exit. It
 will not detach from the terminal.

 *-Q*::
-This option is similar to *-q*, but it will only print the offset without any
-corrections of the clock.
+This option is similar to the *-q* option, except it only prints the offset
+without making any corrections of the clock and it allows *chronyd* to be
+started without root privileges.

 *-r*::
-This option will reload sample histories for each of the servers and refclocks
-being used. These histories are created by using the
-<<chronyc.adoc#dump,*dump*>> command in *chronyc*, or by setting the
-<<chrony.conf.adoc#dumponexit,*dumponexit*>> directive in the configuration
-file. This option is useful if you want to stop and restart *chronyd* briefly
-for any reason, e.g. to install a new version. However, it should be used only
-on systems where the kernel can maintain clock compensation whilst not under
-*chronyd*'s control (i.e. Linux, FreeBSD, NetBSD and Solaris).
+This option will try to reload and then delete files containing sample
+histories for each of the servers and reference clocks being used. The
+files are expected to be in the directory specified by the
+<<chrony.conf.adoc#dumpdir,*dumpdir*>>
+directive in the configuration file. This option is useful if you want to stop
+and restart *chronyd* briefly for any reason, e.g. to install a new version.
+However, it should be used only on systems where the kernel can maintain clock
+compensation whilst not under *chronyd*'s control (i.e. Linux, FreeBSD, NetBSD,
+Solaris, and macOS 10.13 or later).

 *-R*::
 When this option is used, the <<chrony.conf.adoc#initstepslew,*initstepslew*>>
@@ -109,21 +121,30 @@ time and the RTC time, the system time will be set to it to restore the time
 when *chronyd* was previously stopped. This is useful on computers that have no
 RTC or the RTC is broken (e.g. it has no battery).

+*-t* _timeout_::
+This option sets a timeout (in seconds) after which *chronyd* will exit. If the
+clock is not synchronised, it will exit with a non-zero status. This is useful
+with the *-q* or *-Q* option to shorten the maximum time waiting for
+measurements, or with the *-r* option to limit the time when *chronyd* is
+running, but still allow it to adjust the frequency of the system clock.
+
 *-u* _user_::
 This option sets the name of the system user to which *chronyd* will switch
 after start in order to drop root privileges. It overrides the
-<<chrony.conf.adoc#user,*user*>> directive (default _@DEFAULT_USER@_).
+<<chrony.conf.adoc#user,*user*>> directive. The default value is
+_@DEFAULT_USER@_.
 +
 On Linux, *chronyd* needs to be compiled with support for the *libcap* library.
-On Mac OS X, FreeBSD, NetBSD and Solaris *chronyd* forks into two processes.
+On macOS, FreeBSD, NetBSD and Solaris *chronyd* forks into two processes.
 The child process retains root privileges, but can only perform a very limited
 range of privileged system calls on behalf of the parent.

 *-F* _level_::
 This option configures a system call filter when *chronyd* is compiled with
 support for the Linux secure computing (seccomp) facility. In level 1 the
-process is killed when a forbidden system call is made, in level -1 the SYSSIG
-signal is thrown instead and in level 0 the filter is disabled (default 0).
+process is killed when a forbidden system call is made, in level -1 the SIGSYS
+signal is thrown instead and in level 0 the filter is disabled. The default
+value is 0.
 +
 It's recommended to enable the filter only when it's known to work on the
 version of the system where *chrony* is installed as the filter needs to allow
@@ -134,15 +155,24 @@ killed even in normal operation.

 *-P* _priority_::
 On Linux, this option will select the SCHED_FIFO real-time scheduler at the
-specified priority (which must be between 0 and 100). On Mac OS X, this option
-must have either a value of 0 (the default) to disable the thread time
+specified priority (which must be between 0 and 100). On macOS, this option
+must have either a value of 0 to disable the thread time
 constraint policy or 1 for the policy to be enabled. Other systems do not
-support this option.
+support this option. The default value is 0.

 *-m*::
 This option will lock *chronyd* into RAM so that it will never be paged out.
 This mode is only supported on Linux.

+*-x*::
+This option disables the control of the system clock. *chronyd* will not try to
+make any adjustments of the clock. It will assume the clock is free running and
+still track its offset and frequency relative to the estimated true time. This
+option allows *chronyd* to run without the capability to adjust or set the
+system clock (e.g. in some containers) in order to operate as an NTP server. It
+is not recommended to run *chronyd* (with or without *-x*) when another process
+is controlling the system clock.
+
 *-v*::
 With this option *chronyd* will print version number to the terminal and exit.

@@ -161,4 +191,4 @@ https://chrony.tuxfamily.org/.

 == AUTHORS

-chrony was written by Richard Curnow, Miroslav Lichvar and others.
+chrony was written by Richard Curnow, Miroslav Lichvar, and others.
--- a/doc/faq.adoc
+++ b/doc/faq.adoc
@@ -50,7 +50,7 @@ directive can be used for names that resolve to multiple addresses. For good
 reliability the client should have at least three servers. The `iburst` option
 speeds up the initial synchronisation.

-To stabilize the initial synchronisation on the next start, the estimated drift
+To stabilise the initial synchronisation on the next start, the estimated drift
 of the system clock is saved to a file specified by the `driftfile` directive.

 If the system clock can be far from the true time after boot for any reason,
@@ -59,10 +59,10 @@ slewing, which would take a very long time. The `makestep` directive does
 that.

 In order to keep the real-time clock (RTC) close to the true time, so the
-system time is reasonably close to the true time when it's initialized on the
+system time is reasonably close to the true time when it's initialised on the
 next boot from the RTC, the `rtcsync` directive enables a mode in which the
-system time is periodically copied to the RTC. It is supported on Linux and Mac
-OS X.
+system time is periodically copied to the RTC. It is supported on Linux and
+macOS.

 If you want to use public NTP servers from the
 http://www.pool.ntp.org/[pool.ntp.org] project, the minimal _chrony.conf_ file
@@ -79,7 +79,7 @@ rtcsync

 You need to add an `allow` directive to the _chrony.conf_ file in order to open
 the NTP port and allow `chronyd` to reply to client requests. `allow` with no
-specified subnet allows all IPv4 and IPv6 addresses.
+specified subnet allows access from all IPv4 and IPv6 addresses.

 === I have several computers on a LAN. Should be all clients of an external server?

@@ -97,7 +97,7 @@ _chrony.conf_ file. This configuration will be better because
 No. Starting from version 1.25, `chronyd` will keep trying to resolve
 the names specified by the `server`, `pool`, and `peer` directives in an
 increasing interval until it succeeds. The `online` command can be issued from
-`chronyc` to try to resolve them immediately.
+`chronyc` to force `chronyd` to try to resolve the names immediately.

 === How can I make `chronyd` more secure?

@@ -148,15 +148,20 @@ network. It's better to use more than one server, three or four is usually
 recommended as the minimum, so `chronyd` can detect servers that serve false
 time and combine measurements from multiple sources.

+If you have a network card with hardware timestamping supported on Linux, it
+can be enabled by the *hwtimestamp* directive in the _chrony.conf_ file. It
+should make local receive and transmit timestamps of NTP packets much more
+accurate.
+
 There are also useful options which can be set in the `server` directive, they
-are `minpoll`, `maxpoll`, `polltarget`, `maxdelay`, `maxdelayratio` and
-`maxdelaydevratio`.
+are `minpoll`, `maxpoll`, `polltarget`, `maxdelay`, `maxdelayratio`,
+`maxdelaydevratio`, and `xleave`.

 The first three options set the minimum and maximum allowed polling interval,
 and how should be the actual interval adjusted in the specified range. Their
 default values are 6 (64 seconds) for `minpoll`, 10 (1024 seconds) for
-`maxpoll` and 6 (samples) for `polltarget`. The default values should be used
-for general servers on the Internet. With your own NTP servers or if have
+`maxpoll` and 8 (samples) for `polltarget`. The default values should be used
+for general servers on the Internet. With your own NTP servers, or if you have
 permission to poll some servers more frequently, setting these options for
 shorter polling intervals may significantly improve the accuracy of the system
 clock.
@@ -166,6 +171,11 @@ network latency and stability of the system clock (which mainly depends on the
 temperature sensitivity of the crystal oscillator and the maximum rate of the
 temperature change).

+Generally, if the `sourcestats` command usually reports a small number of
+samples retained for a source (e.g. fewer than 16), a shorter polling interval
+should be considered. If the number of samples is usually at the maximum of 64,
+a longer polling interval may work better.
+
 An example of the directive for an NTP server on the Internet that you are
 allowed to poll frequently could be

@@ -173,15 +183,15 @@ allowed to poll frequently could be
 server foo.example.net minpoll 4 maxpoll 6 polltarget 16
 ----

-An example using very short polling intervals for a server located in the same
+An example using shorter polling intervals with a server located in the same
 LAN could be

 ----
 server ntp.local minpoll 2 maxpoll 4 polltarget 30
 ----

-The maxdelay options are useful to ignore measurements with larger delay (e.g.
-due to congestion in the network) and improve the stability of the
+The maxdelay options are useful to ignore measurements with an unusally large
+delay (e.g. due to congestion in the network) and improve the stability of the
 synchronisation. The `maxdelaydevratio` option could be added to the example
 with local NTP server

@@ -189,6 +199,90 @@ with local NTP server
 server ntp.local minpoll 2 maxpoll 4 polltarget 30 maxdelaydevratio 2
 ----

+If your server supports the interleaved mode (e.g. it is running `chronyd`),
+the `xleave` option should be added to the `server` directive in order to allow
+the server to send the client more accurate transmit timestamps (kernel or
+preferably hardware). For example:
+
+----
+server ntp.local minpoll 2 maxpoll 4 xleave
+----
+
+When combined with local hardware timestamping, good network switches, and even
+shorter polling intervals, a sub-microsecond accuracy and stability of a few
+tens of nanoseconds may be possible. For example:
+
+----
+server ntp.local minpoll 0 maxpoll 0 xleave
+hwtimestamp eth0
+----
+
+For best stability, the CPU should be running at a constant frequency (i.e.
+disabled power saving and performance boosting). Energy-Efficient Ethernet
+(EEE) should be disabled in the network. The switches should be configured to
+prioritize NTP packets, especially if the network is expected to be heavily
+loaded.
+
+If it is acceptable for NTP clients in the network to send requests at an
+excessive rate, a sub-second polling interval may be specified. A median filter
+can be enabled in order to update the clock at a reduced rate with more stable
+measurements. For example:
+
+----
+server ntp.local minpoll -6 maxpoll -6 filter 15 xleave
+hwtimestamp eth0 minpoll -6
+----
+
+=== Does `chronyd` have an ntpdate mode?
+
+Yes. With the `-q` option `chronyd` will set the system clock once and exit.
+With the `-Q` option it will print the measured offset without setting the
+clock. If you don't want to use a configuration file, NTP servers can be
+specified on the command line. For example:
+
+----
+# chronyd -q 'pool pool.ntp.org iburst'
+----
+
+The command above would normally take about 5 seconds if the servers were
+well synchronised and responding to all requests. If not synchronised or
+responding, it would take about 10 seconds for `chronyd` to give up and exit
+with a non-zero status. A faster configuration is possible. A single server can
+be used instead of four servers, the number of measurements can be reduced with
+the `maxsamples` option, and a timeout can be specified with the `-t` option.
+The following command would take only up to about 1 second.
+
+----
+# chronyd -q -t 1 'server pool.ntp.org iburst maxsamples 1'
+----
+
+=== Can `chronyd` be configured to control the clock like `ntpd`?
+
+It is not possible to perfectly emulate `ntpd`, but there are some options that
+can configure `chronyd` to behave more like `ntpd`.
+
+In the following example the `minsamples` directive slows down the response to
+changes in the frequency and offset of the clock. The `maxslewrate` and
+`corrtimeratio` directives reduce the maximum frequency error due to an offset
+correction and the `maxdrift` directive reduces the maximum assumed frequency
+error of the clock. The `makestep` directive enables a step threshold and the
+`maxchange` directive enables a panic threshold. The `maxclockerror` directive
+increases the minimum dispersion rate.
+
+----
+minsamples 32
+maxslewrate 500
+corrtimeratio 100
+maxdrift 500
+makestep 0.128 -1
+maxchange 1000 1 1
+maxclockerror 15
+----
+
+Note that increasing `minsamples` may cause the offsets in the `tracking` and
+`sourcestats` reports/logs to be significantly smaller than the actual offsets
+and be unsuitable for monitoring.
+
 === What happened to the `commandkey` and `generatecommandkey` directives?

 They were removed in version 2.2. Authentication is no longer supported in the
@@ -227,8 +321,17 @@ MS Name/IP address         Stratum Poll Reach LastRx Last sample
 === Are NTP servers specified with the `offline` option?

 Check that you're using ``chronyc``'s `online` and `offline` commands
-appropriately. Again, check in _measurements.log_ to see if you're getting any
-data back from the server.
+appropriately. The `activity` command prints the number of sources that are
+currently online and offline. For example:
+
+----
+200 OK
+3 sources online
+0 sources offline
+0 sources doing burst (return to online)
+0 sources doing burst (return to offline)
+0 sources with unknown address
+----

 === Is `chronyd` allowed to step the system clock?

@@ -256,6 +359,49 @@ to
 makestep 1 -1
 ----

+=== Using a Windows NTP server?
+
+A common issue with Windows NTP servers is that they report a very large root
+dispersion (e.g. three seconds or more), which causes `chronyd` to ignore the
+server for being too inaccurate. The `sources` command may show a valid
+measurement, but the server is not selected for synchronisation. You can check
+the root dispersion of the server with the ``chronyc``'s `ntpdata` command.
+
+The `maxdistance` value needs to be increased in _chrony.conf_ to enable
+synchronisation to such a server. For example:
+
+----
+maxdistance 16.0
+----
+
+=== Using a PPS reference clock?
+
+A pulse-per-second (PPS) reference clock requires a non-PPS time source to
+determine which second of UTC corresponds to each pulse. If it is another
+reference clock specified with the `lock` option in the `refclock` directive,
+the offset between the two reference clocks must be smaller than 0.2 seconds in
+order for the PPS reference clock to work. With NMEA reference clocks it is
+common to have a larger offset. It needs to be corrected with the `offset`
+option.
+
+One approach to find out a good value of the `offset` option is to configure
+the reference clocks with the `noselect` option and compare them to an NTP
+server. For example, if the `sourcestats` command showed
+
+----
+Name/IP Address            NP  NR  Span  Frequency  Freq Skew  Offset  Std Dev
+==============================================================================
+PPS0                        0   0     0     +0.000   2000.000     +0ns  4000ms
+NMEA                       58  30   231    -96.494     38.406   +504ms  6080us
+foo.example.net             7   3   200     -2.991     16.141   -107us   492us
+----
+
+the offset of the NMEA source would need to be increased by about 0.504
+seconds. It does not have to be very accurate. As long as the offset of the
+NMEA reference clock stays below 0.2 seconds, the PPS reference clock should be
+able to determine the seconds corresponding to the pulses and allow the samples
+to be used for synchronisation.
+
 == Issues with `chronyc`

 === I keep getting the error `506 Cannot talk to daemon`
@@ -287,12 +433,15 @@ authentication (`commandkey` directive).

 === Why does `chronyc tracking` always print an IPv4 address as reference ID?

-The reference ID is a 32-bit value and is always printed in quad-dotted
-notation, even if the reference source doesn't have an IPv4 address. For IPv4
-addresses, the reference ID is equal to the address, but for IPv6 addresses it
-is the first 32 bits of the MD5 sum of the address. For reference clocks, the
-reference ID is the value specified with the `refid` option in the `refclock`
-directive.
+The reference ID is a 32-bit value and in versions before 3.0 it was printed in
+quad-dotted notation, even if the reference source did not actually have an
+IPv4 address. For IPv4 addresses, the reference ID is equal to the address, but
+for IPv6 addresses it is the first 32 bits of the MD5 sum of the address. For
+reference clocks, the reference ID is the value specified with the `refid`
+option in the `refclock` directive.
+
+Since version 3.0, the reference ID is printed as a hexadecimal number to avoid
+confusion with IPv4 addresses.

 If you need to get the IP address of the current reference source, use the `-n`
 option to disable resolving of IP addresses and read the second field (printed
@@ -308,14 +457,14 @@ Only by the source code. See _cmdmon.c_ (`chronyd` side) and _client.c_
 === What is the real-time clock (RTC)?

 This is the clock which keeps the time even when your computer is turned off.
-It is used to initialize the system clock on boot. It normally doesn't drift
+It is used to initialise the system clock on boot. It normally doesn't drift
 more than few seconds per day.

 There are two approaches how `chronyd` can work with it. One is to use the
 `rtcsync` directive, which tells `chronyd` to enable a kernel mode which sets
 the RTC from the system clock every 11 minutes. `chronyd` itself won't touch
 the RTC. If the computer is not turned off for a long time, the RTC should
-still be close to the true time when the system clock will be initialized from
+still be close to the true time when the system clock will be initialised from
 it on the next boot.

 The other option is to use the `rtcfile` directive, which tells `chronyd` to
@@ -354,16 +503,31 @@ things

 Some other program running on the system may be using the device.

+=== What if my computer does not have an RTC or backup battery?
+
+In this case you can still use the `-s` option to set the system clock to the
+last modification time of the drift file, which should correspond to the system
+time when `chronyd` was previously stopped. The initial system time will be
+increasing across reboots and applications started after `chronyd` will not
+observe backward steps.
+
 == NTP-specific issues

-=== Can `chronyd` be driven from broadcast NTP servers?
+=== Can `chronyd` be driven from broadcast/multicast NTP servers?

-No, the broadcast client mode is not supported and there is currently no plan
-to implement it. The broadcast and multicast modes are inherently less
-accurate and less secure (even with authentication) than the ordinary
-server/client mode and they are not as useful as they used to be. Even with
-very modest hardware a single NTP server can serve time to hundreds of
-thousands of clients using the ordinary mode.
+No, the broadcast/multicast client mode is not supported and there is currently
+no plan to implement it. While the mode may be useful to simplify configuration
+of clients in large networks, it is inherently less accurate and less secure
+(even with authentication) than the ordinary client/server mode.
+
+When configuring a large number of clients in a network, it is recommended to
+use the `pool` directive with a DNS name which resolves to addresses of
+multiple NTP servers. The clients will automatically replace the servers when
+they become unreachable, or otherwise unsuitable for synchronisation, with new
+servers from the pool.
+
+Even with very modest hardware, an NTP server can serve time to hundreds of
+thousands of clients using the ordinary client/server mode.

 === Can `chronyd` transmit broadcast NTP packets?

@@ -373,19 +537,20 @@ to serve time to clients in the network which support the broadcast client mode

 === Can `chronyd` keep the system clock a fixed offset away from real time?

-This is not possible as the program currently stands.
+Yes. Starting from version 3.0, an offset can be specified by the `offset`
+option for all time sources in the _chrony.conf_ file.

 === What happens if the network connection is dropped without using ``chronyc``'s `offline` command first?

-`chronyd` will keep trying to access the server(s) that it thinks are online.
-When the network is connected again, it will take some time (on average half of
-the maximum polling interval) before new measurements are made and the clock is
-corrected. If the servers were set to offline and the `online` command was
-issued when the network was connected, `chronyd` would make new measurements
-immediately.
+`chronyd` will keep trying to access the sources that it thinks are online, and
+it will take longer before new measurements are actually made and the clock is
+corrected when the network is connected again. If the sources were set to
+offline, `chronyd` would make new measurements immediately after issuing the
+`online` command.

-The `auto_offline` option to the `server` entry in the _chrony.conf_ file may
-be useful to switch the servers to the offline state automatically.
+Unless the network connection lasts only few minutes (less than the maximum
+polling interval), the delay is usually not a problem, and it may be acceptable
+to keep all sources online all the time.

 == Operating systems

--- a/doc/installation.adoc
+++ b/doc/installation.adoc
@@ -22,6 +22,26 @@ The software is distributed as source code which has to be compiled. The source
 code is supplied in the form of a gzipped tar file, which unpacks to a
 subdirectory identifying the name and version of the program.

+A C compiler (e.g. `gcc` or `clang`) and GNU Make are needed to build `chrony`.
+The following libraries with their development files, and programs, are needed
+to enable optional features:
+
+* pkg-config: detection of development libraries
+* Nettle, NSS, or LibTomCrypt: secure hash functions (`SECHASH`)
+* libcap: dropping root privileges on Linux (`DROPROOT`)
+* libseccomp: system call filter on Linux (`SCFILTER`)
+* GnuTLS and Nettle: Network Time Security (`NTS`)
+* Editline: line editing in `chronyc` (`READLINE`)
+* timepps.h header: PPS reference clock
+* Asciidoctor: documentation in HTML format
+* Bash: test suite
+
+The following programs are needed when building `chrony` from the git
+repository instead of a released tar file:
+
+* Asciidoctor: manual pages
+* Bison: parser for chronyc settime command
+
 After unpacking the source code, change directory into it, and type

 ----
@@ -29,8 +49,8 @@ After unpacking the source code, change directory into it, and type
 ----

 This is a shell script that automatically determines the system type. There is
-a single optional parameter, `--prefix` which indicates the directory tree
-where the software should be installed. For example,
+an optional parameter `--prefix`, which indicates the directory tree where the
+software should be installed. For example,

 ----
 ./configure --prefix=/opt/free
@@ -40,11 +60,11 @@ will install the `chronyd` daemon into `/opt/free/sbin` and the `chronyc`
 control program into `/opt/free/bin`. The default value for the prefix is
 `/usr/local`.

-The configure script assumes you want to use gcc as your compiler. If you want
-to use a different compiler, you can configure this way:
+The `configure` script assumes you want to use `gcc` as your compiler. If you
+want to use a different compiler, you can configure this way:

 ----
-CC=cc CFLAGS=-O ./configure --prefix=/opt/free
+CC=cc ./configure --prefix=/opt/free
 ----

 for Bourne-family shells, or
@@ -63,11 +83,26 @@ shown. Otherwise, `Makefile` will be generated.
 On Linux, if development files for the libcap library are available, `chronyd`
 will be built with support for dropping root privileges. On other systems no
 extra library is needed. The default user which `chronyd` should run as can be
-specified with the `--with-user` option of the configure script.
+specified with the `--with-user` option of the `configure` script.
+
+If development files for the POSIX threads library are available, `chronyd`
+will be built with support for asynchronous resolving of hostnames specified in
+the `server`, `peer`, and `pool` directives. This allows `chronyd` operating as
+a server to respond to client requests when resolving a hostname. If you don't
+want to enable the support, specify the `--disable-asyncdns` flag to
+`configure`.
+
+If development files for the https://www.lysator.liu.se/~nisse/nettle/[Nettle],
+https://developer.mozilla.org/en-US/docs/Mozilla/Projects/NSS[NSS], or
+http://www.libtom.net/LibTomCrypt/[libtomcrypt] library are available,
+`chronyd` will be built with support for other cryptographic hash functions
+than MD5, which can be used for NTP authentication with a symmetric key. If you
+don't want to enable the support, specify the `--disable-sechash` flag to
+`configure`.

 If development files for the editline or readline library are available,
 `chronyc` will be built with line editing support. If you don't want this,
-specify the `--disable-readline` flag to configure.
+specify the `--disable-readline` flag to `configure`.

 If a `timepps.h` header is available (e.g. from the
 http://linuxpps.org[LinuxPPS project]), `chronyd` will be built with PPS API
@@ -75,6 +110,9 @@ reference clock driver. If the header is installed in a location that isn't
 normally searched by the compiler, you can add it to the searched locations by
 setting the `CPPFLAGS` variable to `-I/path/to/timepps`.

+The `--help` option can be specified to `configure` to print all options
+supported by the script.
+
 Now type

 ----
@@ -122,6 +160,16 @@ unprivileged user for `chronyd` and specify it with the `-u` command-line
 option or the `user` directive in the configuration file, or set the default
 user with the `--with-user` configure option before building.

+== Support for system call filtering
+
+`chronyd` can be built with support for the Linux secure computing (seccomp)
+facility. This requires development files for the
+https://github.com/seccomp/libseccomp[libseccomp] library and the
+`--enable-scfilter` option specified to `configure`. The `-F` option of
+`chronyd` will enable a system call filter, which should significantly reduce
+the kernel attack surface and possibly prevent kernel exploits from `chronyd`
+if it is compromised.
+
 == Support for line editing libraries

 `chronyc` can be built with support for line editing, this allows you to use
@@ -132,12 +180,12 @@ Please note that readline since version 6.0 is licensed under GPLv3+ which is
 incompatible with chrony's license GPLv2. You should use editline instead if
 you don't want to use older readline versions.

-The configure script will automatically enable the line editing support if one
-of the supported libraries is available. If they are both available, the
+The `configure` script will automatically enable the line editing support if
+one of the supported libraries is available. If they are both available, the
 editline library will be used.

-If you don't want to use it (in which case chronyc will use a minimal command
-line interface), invoke configure like this:
+If you don't want to use it (in which case `chronyc` will use a minimal command
+line interface), invoke `configure` like this:

 ----
 ./configure --disable-readline other-options...
@@ -161,12 +209,12 @@ normally searched by the compiler and linker, you need to use extra options:

 == Extra options for package builders

-The configure and make procedures have some extra options that may be useful if
-you are building a distribution package for chrony.
+The `configure` and `make` procedures have some extra options that may be
+useful if you are building a distribution package for `chrony`.

-The `--mandir=DIR` option to configure specifies an install directory for the
-man pages. This overrides the `man` subdirectory of the argument to the
--prefix option.
+The `--mandir=DIR` option to `configure` specifies an installation directory
+for the man pages. This overrides the `man` subdirectory of the argument to the
+`--prefix` option.

 ----
 ./configure --prefix=/usr --mandir=/usr/share/man
@@ -174,8 +222,8 @@ man pages. This overrides the `man` subdirectory of the argument to the

 to set both options together.

-The final option is the `DESTDIR` option to the make command. For example, you
-could use the commands
+The final option is the `DESTDIR` option to the `make` command. For example,
+you could use the commands

 ----
 ./configure --prefix=/usr --mandir=/usr/share/man
--- a/examples/chrony-wait.service
+++ b/examples/chrony-wait.service
@@ -1,5 +1,6 @@
 [Unit]
 Description=Wait for chrony to synchronize system clock
+Documentation=man:chronyc(1)
 After=chronyd.service
 Requires=chronyd.service
 Before=time-sync.target
@@ -9,7 +10,7 @@ Wants=time-sync.target
 Type=oneshot
 # Wait up to ~10 minutes for chronyd to synchronize and the remaining
 # clock correction to be less than 0.1 seconds
-ExecStart=/usr/bin/chronyc waitsync 600 0.1 0.0 1
+ExecStart=/usr/bin/chronyc -h 127.0.0.1,::1 waitsync 600 0.1 0.0 1
 RemainAfterExit=yes
 StandardOutput=null

--- a/examples/chrony.conf.example1
+++ b/examples/chrony.conf.example1
@@ -4,8 +4,8 @@ pool pool.ntp.org iburst
 # Record the rate at which the system clock gains/losses time.
 driftfile /var/lib/chrony/drift

-# In first three updates step the system clock instead of slew
-# if the adjustment is larger than 1 second.
+# Allow the system clock to be stepped in the first three updates
+# if its offset is larger than 1 second.
 makestep 1.0 3

 # Enable kernel synchronization of the real-time clock (RTC).
--- a/examples/chrony.conf.example2
+++ b/examples/chrony.conf.example2
@@ -5,22 +5,32 @@ pool pool.ntp.org iburst
 # Record the rate at which the system clock gains/losses time.
 driftfile /var/lib/chrony/drift

-# In first three updates step the system clock instead of slew
-# if the adjustment is larger than 1 second.
+# Allow the system clock to be stepped in the first three updates
+# if its offset is larger than 1 second.
 makestep 1.0 3

 # Enable kernel synchronization of the real-time clock (RTC).
 rtcsync

-# Allow NTP client access from local network.
-#allow 192.168/16
+# Enable hardware timestamping on all interfaces that support it.
+#hwtimestamp *

-# Serve time even if not synchronized to any NTP server.
+# Increase the minimum number of selectable sources required to adjust
+# the system clock.
+#minsources 2
+
+# Allow NTP client access from local network.
+#allow 192.168.0.0/16
+
+# Serve time even if not synchronized to a time source.
 #local stratum 10

 # Specify file containing keys for NTP authentication.
 #keyfile /etc/chrony.keys

+# Get TAI-UTC offset and leap seconds from the system tz database.
+#leapsectz right/UTC
+
 # Specify directory for log files.
 logdir /var/log/chrony

--- a/examples/chrony.conf.example3
+++ b/examples/chrony.conf.example3
@@ -33,42 +33,30 @@

 ! pool pool.ntp.org iburst
 
-# However, for dial-up use you probably want these instead.  The word
-# 'offline' means that the server is not visible at boot time.  Use
-# chronyc's 'online' command to tell chronyd that these servers have
-# become visible after you go on-line.
-
-! server foo.example.net offline
-! server bar.example.net offline
-! server baz.example.net offline
-
-! pool pool.ntp.org offline
-
-# You may want to specify NTP 'peers' instead.  If you run a network
-# with a lot of computers and want several computers running chrony to
-# have the 'front-line' interface to the public NTP servers, you can
-# 'peer' these machines together to increase robustness.
-
-! peer foo.example.net
-
-# There are other options to the 'server' and 'peer' directives that you
-# might want to use.  For example, you can ignore measurements whose
-# round-trip-time is too large (indicating that the measurement is
-# probably useless, because you don't know which way the measurement
-# message got held up.)  Consult the full documentation for details.
-
 #######################################################################
 ### AVOIDING POTENTIALLY BOGUS CHANGES TO YOUR CLOCK
 #
 # To avoid changes being made to your computer's gain/loss compensation
 # when the measurement history is too erratic, you might want to enable
-# one of the following lines.  The first seems good for dial-up (or
-# other high-latency connections like slow leased lines), the second
-# seems OK for a LAN environment.
+# one of the following lines.  The first seems good with servers on the
+# Internet, the second seems OK for a LAN environment.

 ! maxupdateskew 100
 ! maxupdateskew 5

+# If you want to increase the minimum number of selectable sources
+# required to update the system clock in order to make the
+# synchronisation more reliable, uncomment (and edit) the following
+# line.
+
+! minsources 2
+
+# If your computer has a good stable clock (e.g. it is not a virtual
+# machine), you might also want to reduce the maximum assumed drift
+# (frequency error) of the clock (the value is specified in ppm).
+
+! maxdrift 100
+
 #######################################################################
 ### FILENAMES ETC
 # Chrony likes to keep information about your computer's clock in files.
@@ -107,7 +95,13 @@ driftfile /var/lib/chrony/drift
 # still running and bail out.  If you want to change the path to the PID
 # file, uncomment this line and edit it.  The default path is shown.

-! pidfile /var/run/chronyd.pid
+! pidfile /var/run/chrony/chronyd.pid
+
+# If the system timezone database is kept up to date and includes the
+# right/UTC timezone, chronyd can use it to determine the current
+# TAI-UTC offset and when will the next leap second occur.
+
+! leapsectz right/UTC

 #######################################################################
 ### INITIAL CLOCK CORRECTION
@@ -181,13 +175,12 @@ driftfile /var/lib/chrony/drift
 # machine accesses it.  The information can be accessed by the 'clients'
 # command of chronyc.  You can disable this facility by uncommenting the
 # following line.  This will save a bit of memory if you have many
-# clients.
+# clients and it will also disable support for the interleaved mode.

 ! noclientlog

 # The clientlog size is limited to 512KB by default.  If you have many
-# clients, especially in many different subnets, you might want to
-# increase the limit. 
+# clients, you might want to increase the limit.

 ! clientloglimit 4194304

@@ -196,7 +189,7 @@ driftfile /var/lib/chrony/drift
 # clients that are sending requests too frequently, uncomment and edit
 # the following line.

-! limitrate interval 3 burst 8
+! ratelimit interval 3 burst 8

 #######################################################################
 ### REPORTING BIG CLOCK CHANGES
@@ -243,7 +236,17 @@ driftfile /var/lib/chrony/drift
 # Rate limiting can be enabled also for command packets.  (Note,
 # commands from localhost are never limited.)

-! cmdratelimit interval 1 burst 16
+! cmdratelimit interval -4 burst 16
+
+#######################################################################
+### HARDWARE TIMESTAMPING
+# On Linux, if the network interface controller and its driver support
+# hardware timestamping, it can significantly improve the accuracy of
+# synchronisation. It can be enabled on specified interfaces only, or it
+# can be enabled on all interfaces that support it.
+
+! hwtimestamp eth0
+! hwtimestamp *

 #######################################################################
 ### REAL TIME CLOCK
@@ -274,6 +277,12 @@ driftfile /var/lib/chrony/drift

 ! rtcdevice /dev/misc/rtc

+# Alternatively, if not using the -s option, this directive can be used
+# to enable a mode in which the RTC is periodically set to the system
+# time, with no tracking of its drift.
+
+! rtcsync
+
 #######################################################################
 ### REAL TIME SCHEDULER
 # This directive tells chronyd to use the real-time FIFO scheduler with the
--- a/examples/chrony.keys.example
+++ b/examples/chrony.keys.example
@@ -1,6 +1,7 @@
-# This is an example chrony keys file.  It is used for NTP authentication with
-# symmetric keys.  It should be readable only by root or the user to which
-# chronyd is configured to switch to after start.
+# This is an example chrony keys file.  It enables authentication of NTP
+# packets with symmetric keys when its location is specified by the keyfile
+# directive in chrony.conf(5).  It should be readable only by root and the
+# user under which chronyd is running.
 #
 # Don't use the example keys!  It's recommended to generate random keys using
 # the chronyc keygen command.
--- a/examples/chrony.nm-dispatcher
+++ b/examples/chrony.nm-dispatcher
@@ -1,17 +1,15 @@
 #!/bin/sh
-# This is a NetworkManager dispatcher script for chronyd to set its NTP sources
-# online/offline when a default route is configured/removed on the system.
+# This is a NetworkManager dispatcher / networkd-dispatcher script for
+# chronyd to set its NTP sources online or offline when a network interface
+# is configured or removed

 export LC_ALL=C

-if [ "$2" = "up" ]; then
-	/sbin/ip route list dev "$1" | grep -q '^default' &&
-		/usr/bin/chronyc online > /dev/null 2>&1
-fi
+# For NetworkManager consider only up/down events
+[ $# -ge 2 ] && [ "$2" != "up" ] && [ "$2" != "down" ] && exit 0

-if [ "$2" = "down" ]; then
-	/sbin/ip route list | grep -q '^default' ||
-		/usr/bin/chronyc offline > /dev/null 2>&1
-fi
+# Note: for networkd-dispatcher routable.d ~= on and off.d ~= off
+
+chronyc onoffline > /dev/null 2>&1

 exit 0
--- a/examples/chrony.spec
+++ b/examples/chrony.spec
@@ -1,46 +0,0 @@
-%global chrony_version @@VERSION@@
-%if 0%(echo %{chrony_version} | grep -q pre && echo 1)
-%global prerelease %(echo %{chrony_version} | sed 's/.*-//')
-%endif
-Summary: An NTP client/server
-Name: chrony
-Version: %(echo %{chrony_version} | sed 's/-.*//')
-Release: %{!?prerelease:1}%{?prerelease:0.1.%{prerelease}}
-Source: chrony-%{version}%{?prerelease:-%{prerelease}}.tar.gz
-License: GPLv2
-Group: Applications/Utilities
-BuildRoot: %{_tmppath}/%{name}-%{version}-root-%(id -u -n)
-
-%description
-chrony is a client and server for the Network Time Protocol (NTP).
-This program keeps your computer's clock accurate. It was specially
-designed to support systems with intermittent Internet connections,
-but it also works well in permanently connected environments. It can
-also use hardware reference clocks, the system real-time clock, or
-manual input as time references.
-
-%prep
-%setup -q -n %{name}-%{version}%{?prerelease:-%{prerelease}}
-
-%build
-./configure \
-	--prefix=%{_prefix} \
-	--bindir=%{_bindir} \
-	--sbindir=%{_sbindir} \
-	--mandir=%{_mandir}
-make
-
-%install
-rm -rf $RPM_BUILD_ROOT
-make install DESTDIR=$RPM_BUILD_ROOT
-
-%files
-%{_sbindir}/chronyd
-%{_bindir}/chronyc
-%{_mandir}/man1/chronyc.1.gz
-%{_mandir}/man5/chrony.conf.5.gz
-%{_mandir}/man8/chronyd.8.gz
-%doc README FAQ NEWS COPYING
-%doc examples/chrony.conf.example*
-%doc examples/chrony.keys.example
-
--- a/examples/chronyd.service
+++ b/examples/chronyd.service
@@ -1,13 +1,18 @@
 [Unit]
 Description=NTP client/server
+Documentation=man:chronyd(8) man:chrony.conf(5)
 After=ntpdate.service sntp.service ntpd.service
 Conflicts=ntpd.service systemd-timesyncd.service
+ConditionCapability=CAP_SYS_TIME

 [Service]
 Type=forking
-PIDFile=/var/run/chronyd.pid
+PIDFile=/run/chrony/chronyd.pid
 EnvironmentFile=-/etc/sysconfig/chronyd
 ExecStart=/usr/sbin/chronyd $OPTIONS
+PrivateTmp=yes
+ProtectHome=yes
+ProtectSystem=full

 [Install]
 WantedBy=multi-user.target
--- a/hash_intmd5.c
+++ b/hash_intmd5.c
@@ -29,6 +29,7 @@
 #include "sysincl.h"
 #include "hash.h"
 #include "memory.h"
+#include "util.h"

 #include "md5.c"

@@ -49,18 +50,17 @@ HSH_Hash(int id, const unsigned char *in1, unsigned int in1_len,
    const unsigned char *in2, unsigned int in2_len,
    unsigned char *out, unsigned int out_len)
 {
-  if (out_len < 16)
-    return 0;
-
  MD5Init(&ctx);
  MD5Update(&ctx, in1, in1_len);
  if (in2)
    MD5Update(&ctx, in2, in2_len);
  MD5Final(&ctx);

-  memcpy(out, ctx.digest, 16);
+  out_len = MIN(out_len, 16);

-  return 16;
+  memcpy(out, ctx.digest, out_len);
+
+  return out_len;
 }

 void
--- a/hash_nettle.c
+++ b/hash_nettle.c
@@ -0,0 +1,119 @@
+/*
+  chronyd/chronyc - Programs for keeping computer clocks accurate.
+
+ **********************************************************************
+ * Copyright (C) Miroslav Lichvar  2018
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ * 
+ **********************************************************************
+
+  =======================================================================
+
+  Routines implementing crypto hashing using the nettle library.
+
+  */
+
+#include "config.h"
+
+#include "sysincl.h"
+
+#include <nettle/nettle-meta.h>
+
+#include "hash.h"
+#include "memory.h"
+
+struct hash {
+  const char *name;
+  const char *int_name;
+  const struct nettle_hash *nettle_hash;
+  void *context;
+};
+
+static struct hash hashes[] = {
+  { "MD5", "md5", NULL, NULL },
+  { "SHA1", "sha1", NULL, NULL },
+  { "SHA256", "sha256", NULL, NULL },
+  { "SHA384", "sha384", NULL, NULL },
+  { "SHA512", "sha512", NULL, NULL },
+  { "SHA3-224", "sha3_224", NULL, NULL },
+  { "SHA3-256", "sha3_256", NULL, NULL },
+  { "SHA3-384", "sha3_384", NULL, NULL },
+  { "SHA3-512", "sha3_512", NULL, NULL },
+  { NULL, NULL, NULL, NULL }
+};
+
+int
+HSH_GetHashId(const char *name)
+{
+  int id, nid;
+
+  for (id = 0; hashes[id].name; id++) {
+    if (!strcmp(name, hashes[id].name))
+      break;
+  }
+
+  if (!hashes[id].name)
+    return -1;
+
+  if (hashes[id].context)
+    return id;
+
+  for (nid = 0; nettle_hashes[nid]; nid++) {
+    if (!strcmp(hashes[id].int_name, nettle_hashes[nid]->name))
+      break;
+  }
+
+  if (!nettle_hashes[nid] || !nettle_hashes[nid]->context_size || !nettle_hashes[nid]->init)
+    return -1;
+
+  hashes[id].nettle_hash = nettle_hashes[nid];
+  hashes[id].context = Malloc(hashes[id].nettle_hash->context_size);
+
+  return id;
+}
+
+unsigned int
+HSH_Hash(int id, const unsigned char *in1, unsigned int in1_len,
+         const unsigned char *in2, unsigned int in2_len,
+         unsigned char *out, unsigned int out_len)
+{
+  const struct nettle_hash *hash;
+  void *context;
+
+  hash = hashes[id].nettle_hash;
+  context = hashes[id].context;
+
+  if (out_len > hash->digest_size)
+    out_len = hash->digest_size;
+
+  hash->init(context);
+  hash->update(context, in1_len, in1);
+  if (in2)
+    hash->update(context, in2_len, in2);
+  hash->digest(context, out_len, out);
+
+  return out_len;
+}
+
+void
+HSH_Finalise(void)
+{
+  int i;
+
+  for (i = 0; hashes[i].name; i++) {
+    if (hashes[i].context)
+      Free(hashes[i].context);
+  }
+}
--- a/hash_nss.c
+++ b/hash_nss.c
@@ -32,6 +32,7 @@
 #include <nsslowhash.h>

 #include "hash.h"
+#include "util.h"

 static NSSLOWInitContext *ictx;

@@ -78,13 +79,17 @@ HSH_Hash(int id, const unsigned char *in1, unsigned int in1_len,
    const unsigned char *in2, unsigned int in2_len,
    unsigned char *out, unsigned int out_len)
 {
-  unsigned int ret;
+  unsigned char buf[MAX_HASH_LENGTH];
+  unsigned int ret = 0;

  NSSLOWHASH_Begin(hashes[id].context);
  NSSLOWHASH_Update(hashes[id].context, in1, in1_len);
  if (in2)
    NSSLOWHASH_Update(hashes[id].context, in2, in2_len);
-  NSSLOWHASH_End(hashes[id].context, out, &ret, out_len);
+  NSSLOWHASH_End(hashes[id].context, buf, &ret, sizeof (buf));
+
+  ret = MIN(ret, out_len);
+  memcpy(out, buf, ret);

  return ret;
 }
--- a/hash_tomcrypt.c
+++ b/hash_tomcrypt.c
@@ -2,7 +2,7 @@
  chronyd/chronyc - Programs for keeping computer clocks accurate.

 **********************************************************************
- * Copyright (C) Miroslav Lichvar  2012
+ * Copyright (C) Miroslav Lichvar  2012, 2018
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
@@ -29,6 +29,7 @@

 #include "config.h"
 #include "hash.h"
+#include "util.h"

 struct hash {
  const char *name;
@@ -38,18 +39,6 @@ struct hash {

 static const struct hash hashes[] = {
  { "MD5", "md5", &md5_desc },
-#ifdef LTC_RIPEMD128
-  { "RMD128", "rmd128", &rmd128_desc },
-#endif
-#ifdef LTC_RIPEMD160
-  { "RMD160", "rmd160", &rmd160_desc },
-#endif
-#ifdef LTC_RIPEMD256
-  { "RMD256", "rmd256", &rmd256_desc },
-#endif
-#ifdef LTC_RIPEMD320
-  { "RMD320", "rmd320", &rmd320_desc },
-#endif
 #ifdef LTC_SHA1
  { "SHA1", "sha1", &sha1_desc },
 #endif
@@ -62,6 +51,12 @@ static const struct hash hashes[] = {
 #ifdef LTC_SHA512
  { "SHA512", "sha512", &sha512_desc },
 #endif
+#ifdef LTC_SHA3
+  { "SHA3-224", "sha3-224", &sha3_224_desc },
+  { "SHA3-256", "sha3-256", &sha3_256_desc },
+  { "SHA3-384", "sha3-384", &sha3_384_desc },
+  { "SHA3-512", "sha3-512", &sha3_512_desc },
+#endif
 #ifdef LTC_TIGER
  { "TIGER", "tiger", &tiger_desc },
 #endif
@@ -99,19 +94,24 @@ HSH_Hash(int id, const unsigned char *in1, unsigned int in1_len,
    const unsigned char *in2, unsigned int in2_len,
    unsigned char *out, unsigned int out_len)
 {
+  unsigned char buf[MAX_HASH_LENGTH];
  unsigned long len;
  int r;

-  len = out_len;
+  len = sizeof (buf);
  if (in2)
-    r = hash_memory_multi(id, out, &len,
-        in1, (unsigned long)in1_len, in2, (unsigned long)in2_len, NULL, 0);
+    r = hash_memory_multi(id, buf, &len,
+                          in1, (unsigned long)in1_len,
+                          in2, (unsigned long)in2_len, NULL, 0);
  else
-    r = hash_memory(id, in1, in1_len, out, &len);
+    r = hash_memory(id, in1, in1_len, buf, &len);

  if (r != CRYPT_OK)
    return 0;

+  len = MIN(len, out_len);
+  memcpy(out, buf, len);
+
  return len;
 }

--- a/hwclock.c
+++ b/hwclock.c
@@ -0,0 +1,227 @@
+/*
+  chronyd/chronyc - Programs for keeping computer clocks accurate.
+
+ **********************************************************************
+ * Copyright (C) Miroslav Lichvar  2016-2018
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ * 
+ **********************************************************************
+
+  =======================================================================
+
+  Tracking of hardware clocks (e.g. RTC, PHC)
+  */
+
+#include "config.h"
+
+#include "sysincl.h"
+
+#include "array.h"
+#include "hwclock.h"
+#include "local.h"
+#include "logging.h"
+#include "memory.h"
+#include "regress.h"
+#include "util.h"
+
+/* Minimum and maximum number of samples per clock */
+#define MIN_SAMPLES 2
+#define MAX_SAMPLES 64
+
+/* Maximum acceptable frequency offset of the clock */
+#define MAX_FREQ_OFFSET (2.0 / 3.0)
+
+struct HCL_Instance_Record {
+  /* HW and local reference timestamp */
+  struct timespec hw_ref;
+  struct timespec local_ref;
+
+  /* Samples stored as intervals (uncorrected for frequency error)
+     relative to local_ref and hw_ref */
+  double *x_data;
+  double *y_data;
+
+  /* Minimum, maximum and current number of samples */
+  int min_samples;
+  int max_samples;
+  int n_samples;
+
+  /* Maximum error of the last sample */
+  double last_err;
+
+  /* Minimum interval between samples */
+  double min_separation;
+
+  /* Flag indicating the offset and frequency values are valid */
+  int valid_coefs;
+
+  /* Estimated offset and frequency of HW clock relative to local clock */
+  double offset;
+  double frequency;
+};
+
+/* ================================================== */
+
+static void
+handle_slew(struct timespec *raw, struct timespec *cooked, double dfreq,
+            double doffset, LCL_ChangeType change_type, void *anything)
+{
+  HCL_Instance clock;
+  double delta;
+
+  clock = anything;
+
+  if (clock->n_samples)
+    UTI_AdjustTimespec(&clock->local_ref, cooked, &clock->local_ref, &delta, dfreq, doffset);
+  if (clock->valid_coefs)
+    clock->frequency /= 1.0 - dfreq;
+}
+
+/* ================================================== */
+
+HCL_Instance
+HCL_CreateInstance(int min_samples, int max_samples, double min_separation)
+{
+  HCL_Instance clock;
+
+  min_samples = CLAMP(MIN_SAMPLES, min_samples, MAX_SAMPLES);
+  max_samples = CLAMP(MIN_SAMPLES, max_samples, MAX_SAMPLES);
+  max_samples = MAX(min_samples, max_samples);
+
+  clock = MallocNew(struct HCL_Instance_Record);
+  clock->x_data = MallocArray(double, max_samples);
+  clock->y_data = MallocArray(double, max_samples);
+  clock->x_data[max_samples - 1] = 0.0;
+  clock->y_data[max_samples - 1] = 0.0;
+  clock->min_samples = min_samples;
+  clock->max_samples = max_samples;
+  clock->n_samples = 0;
+  clock->valid_coefs = 0;
+  clock->min_separation = min_separation;
+
+  LCL_AddParameterChangeHandler(handle_slew, clock);
+
+  return clock;
+}
+
+/* ================================================== */
+
+void HCL_DestroyInstance(HCL_Instance clock)
+{
+  LCL_RemoveParameterChangeHandler(handle_slew, clock);
+  Free(clock->y_data);
+  Free(clock->x_data);
+  Free(clock);
+}
+
+/* ================================================== */
+
+int
+HCL_NeedsNewSample(HCL_Instance clock, struct timespec *now)
+{
+  if (!clock->n_samples ||
+      fabs(UTI_DiffTimespecsToDouble(now, &clock->local_ref)) >= clock->min_separation)
+    return 1;
+
+  return 0;
+}
+
+/* ================================================== */
+
+void
+HCL_AccumulateSample(HCL_Instance clock, struct timespec *hw_ts,
+                     struct timespec *local_ts, double err)
+{
+  double hw_delta, local_delta, local_freq, raw_freq;
+  int i, n_runs, best_start;
+
+  local_freq = 1.0 - LCL_ReadAbsoluteFrequency() / 1.0e6;
+
+  /* Shift old samples */
+  if (clock->n_samples) {
+    if (clock->n_samples >= clock->max_samples)
+      clock->n_samples--;
+
+    hw_delta = UTI_DiffTimespecsToDouble(hw_ts, &clock->hw_ref);
+    local_delta = UTI_DiffTimespecsToDouble(local_ts, &clock->local_ref) / local_freq;
+
+    if (hw_delta <= 0.0 || local_delta < clock->min_separation / 2.0) {
+      clock->n_samples = 0;
+      DEBUG_LOG("HW clock reset interval=%f", local_delta);
+    }
+
+    for (i = clock->max_samples - clock->n_samples; i < clock->max_samples; i++) {
+      clock->y_data[i - 1] = clock->y_data[i] - hw_delta;
+      clock->x_data[i - 1] = clock->x_data[i] - local_delta;
+    }
+  }
+
+  clock->n_samples++;
+  clock->hw_ref = *hw_ts;
+  clock->local_ref = *local_ts;
+  clock->last_err = err;
+
+  /* Get new coefficients */
+  clock->valid_coefs =
+    RGR_FindBestRobustRegression(clock->x_data + clock->max_samples - clock->n_samples,
+                                 clock->y_data + clock->max_samples - clock->n_samples,
+                                 clock->n_samples, 1.0e-10, &clock->offset, &raw_freq,
+                                 &n_runs, &best_start);
+
+  if (!clock->valid_coefs) {
+    DEBUG_LOG("HW clock needs more samples");
+    return;
+  }
+
+  clock->frequency = raw_freq / local_freq;
+
+  /* Drop unneeded samples */
+  if (clock->n_samples > clock->min_samples)
+    clock->n_samples -= MIN(best_start, clock->n_samples - clock->min_samples);
+
+  /* If the fit doesn't cross the error interval of the last sample,
+     or the frequency is not sane, drop all samples and start again */
+  if (fabs(clock->offset) > err ||
+      fabs(clock->frequency - 1.0) > MAX_FREQ_OFFSET) {
+    DEBUG_LOG("HW clock reset");
+    clock->n_samples = 0;
+    clock->valid_coefs = 0;
+  }
+
+  DEBUG_LOG("HW clock samples=%d offset=%e freq=%e raw_freq=%e err=%e ref_diff=%e",
+            clock->n_samples, clock->offset, clock->frequency - 1.0, raw_freq - 1.0, err,
+            UTI_DiffTimespecsToDouble(&clock->hw_ref, &clock->local_ref));
+}
+
+/* ================================================== */
+
+int
+HCL_CookTime(HCL_Instance clock, struct timespec *raw, struct timespec *cooked, double *err)
+{
+  double offset, elapsed;
+
+  if (!clock->valid_coefs)
+    return 0;
+
+  elapsed = UTI_DiffTimespecsToDouble(raw, &clock->hw_ref);
+  offset = elapsed / clock->frequency - clock->offset;
+  UTI_AddDoubleToTimespec(&clock->local_ref, offset, cooked);
+
+  /* Fow now, just return the error of the last sample */
+  if (err)
+    *err = clock->last_err;
+
+  return 1;
+}
--- a/hwclock.h
+++ b/hwclock.h
@@ -0,0 +1,49 @@
+/*
+  chronyd/chronyc - Programs for keeping computer clocks accurate.
+
+ **********************************************************************
+ * Copyright (C) Miroslav Lichvar  2016
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ * 
+ **********************************************************************
+
+  =======================================================================
+
+  Header for tracking of hardware clocks */
+
+#ifndef GOT_HWCLOCK_H
+#define GOT_HWCLOCK_H
+
+typedef struct HCL_Instance_Record *HCL_Instance;
+
+/* Create a new HW clock instance */
+extern HCL_Instance HCL_CreateInstance(int min_samples, int max_samples,
+                                       double min_separation);
+
+/* Destroy a HW clock instance */
+extern void HCL_DestroyInstance(HCL_Instance clock);
+
+/* Check if a new sample should be accumulated at this time */
+extern int HCL_NeedsNewSample(HCL_Instance clock, struct timespec *now);
+
+/* Accumulate a new sample */
+extern void HCL_AccumulateSample(HCL_Instance clock, struct timespec *hw_ts,
+                                 struct timespec *local_ts, double err);
+
+/* Convert raw hardware time to cooked local time */
+extern int HCL_CookTime(HCL_Instance clock, struct timespec *raw, struct timespec *cooked,
+                        double *err);
+
+#endif
--- a/keys.c
+++ b/keys.c
@@ -32,6 +32,7 @@

 #include "array.h"
 #include "keys.h"
+#include "cmac.h"
 #include "cmdparse.h"
 #include "conf.h"
 #include "memory.h"
@@ -42,11 +43,22 @@
 /* Consider 80 bits as the absolute minimum for a secure key */
 #define MIN_SECURE_KEY_LENGTH 10

+typedef enum {
+  NTP_MAC,
+  CMAC,
+} KeyClass;
+
 typedef struct {
  uint32_t id;
-  char *val;
-  int len;
-  int hash_id;
+  KeyClass class;
+  union {
+    struct {
+      unsigned char *value;
+      int length;
+      int hash_id;
+    } ntp_mac;
+    CMC_Instance cmac;
+  } data;
  int auth_delay;
 } Key;

@@ -62,9 +74,21 @@ static void
 free_keys(void)
 {
  unsigned int i;
+  Key *key;

-  for (i = 0; i < ARR_GetSize(keys); i++)
-    Free(((Key *)ARR_GetElement(keys, i))->val);
+  for (i = 0; i < ARR_GetSize(keys); i++) {
+    key = ARR_GetElement(keys, i);
+    switch (key->class) {
+      case NTP_MAC:
+        Free(key->data.ntp_mac.value);
+        break;
+      case CMAC:
+        CMC_DestroyInstance(key->data.cmac);
+        break;
+      default:
+        assert(0);
+    }
+  }

  ARR_SetSize(keys, 0);
  cache_valid = 0;
@@ -103,29 +127,49 @@ static int
 determine_hash_delay(uint32_t key_id)
 {
  NTP_Packet pkt;
-  struct timeval before, after;
-  unsigned long usecs, min_usecs=0;
-  int i;
+  struct timespec before, after;
+  double diff, min_diff;
+  int i, nsecs;
+
+  memset(&pkt, 0, sizeof (pkt));

  for (i = 0; i < 10; i++) {
    LCL_ReadRawTime(&before);
-    KEY_GenerateAuth(key_id, (unsigned char *)&pkt, NTP_NORMAL_PACKET_LENGTH,
-        (unsigned char *)&pkt.auth_data, sizeof (pkt.auth_data));
+    KEY_GenerateAuth(key_id, (unsigned char *)&pkt, NTP_HEADER_LENGTH,
+                     (unsigned char *)&pkt + NTP_HEADER_LENGTH,
+                     sizeof (pkt) - NTP_HEADER_LENGTH);
    LCL_ReadRawTime(&after);

-    usecs = (after.tv_sec - before.tv_sec) * 1000000 + (after.tv_usec - before.tv_usec);
+    diff = UTI_DiffTimespecsToDouble(&after, &before);

-    if (i == 0 || usecs < min_usecs) {
-      min_usecs = usecs;
-    }
+    if (i == 0 || min_diff > diff)
+      min_diff = diff;
  }

-  /* Add on a bit extra to allow for copying, conversions etc */
-  min_usecs += min_usecs >> 4;
+  nsecs = 1.0e9 * min_diff;

-  DEBUG_LOG(LOGF_Keys, "authentication delay for key %"PRIu32": %ld useconds", key_id, min_usecs);
+  DEBUG_LOG("authentication delay for key %"PRIu32": %d nsecs", key_id, nsecs);

-  return min_usecs;
+  return nsecs;
+}
+
+/* ================================================== */
+/* Decode key encoded in ASCII or HEX */
+
+static int
+decode_key(char *key)
+{
+  int len = strlen(key);
+
+  if (!strncmp(key, "ASCII:", 6)) {
+    memmove(key, key + 6, len - 6);
+    return len - 6;
+  } else if (!strncmp(key, "HEX:", 4)) {
+    return UTI_HexToBytes(key + 4, key, len);
+  } else {
+    /* assume ASCII */
+    return len;
+  }
 }

 /* ================================================== */
@@ -153,11 +197,11 @@ compare_keys_by_id(const void *a, const void *b)
 void
 KEY_Reload(void)
 {
-  unsigned int i, line_number;
+  unsigned int i, line_number, key_length, cmac_key_length;
  FILE *in;
-  uint32_t key_id;
-  char line[2048], *keyval, *key_file;
-  const char *hashname;
+  char line[2048], *key_file, *key_value;
+  const char *key_type;
+  int hash_id;
  Key key;

  free_keys();
@@ -168,9 +212,9 @@ KEY_Reload(void)
  if (!key_file)
    return;

-  in = fopen(key_file, "r");
+  in = UTI_OpenFile(NULL, key_file, NULL, 'r', 0);
  if (!in) {
-    LOG(LOGS_WARN, LOGF_Keys, "Could not open keyfile %s", key_file);
+    LOG(LOGS_WARN, "Could not open keyfile %s", key_file);
    return;
  }

@@ -181,26 +225,43 @@ KEY_Reload(void)
    if (!*line)
      continue;

-    if (!CPS_ParseKey(line, &key_id, &hashname, &keyval)) {
-      LOG(LOGS_WARN, LOGF_Keys, "Could not parse key at line %d in file %s", line_number, key_file);
+    memset(&key, 0, sizeof (key));
+
+    if (!CPS_ParseKey(line, &key.id, &key_type, &key_value)) {
+      LOG(LOGS_WARN, "Could not parse key at line %u in file %s", line_number, key_file);
      continue;
    }

-    key.hash_id = HSH_GetHashId(hashname);
-    if (key.hash_id < 0) {
-      LOG(LOGS_WARN, LOGF_Keys, "Unknown hash function in key %"PRIu32, key_id);
+    key_length = decode_key(key_value);
+    if (key_length == 0) {
+      LOG(LOGS_WARN, "Could not decode key %"PRIu32, key.id);
      continue;
    }

-    key.len = UTI_DecodePasswordFromText(keyval);
-    if (!key.len) {
-      LOG(LOGS_WARN, LOGF_Keys, "Could not decode password in key %"PRIu32, key_id);
+    hash_id = HSH_GetHashId(key_type);
+    cmac_key_length = CMC_GetKeyLength(key_type);
+
+    if (hash_id >= 0) {
+      key.class = NTP_MAC;
+      key.data.ntp_mac.value = MallocArray(unsigned char, key_length);
+      memcpy(key.data.ntp_mac.value, key_value, key_length);
+      key.data.ntp_mac.length = key_length;
+      key.data.ntp_mac.hash_id = hash_id;
+    } else if (cmac_key_length > 0) {
+      if (cmac_key_length != key_length) {
+        LOG(LOGS_WARN, "Invalid length of %s key %"PRIu32" (expected %u bits)",
+            key_type, key.id, 8 * cmac_key_length);
+        continue;
+      }
+
+      key.class = CMAC;
+      key.data.cmac = CMC_CreateInstance(key_type, (unsigned char *)key_value, key_length);
+      assert(key.data.cmac);
+    } else {
+      LOG(LOGS_WARN, "Unknown hash function or cipher in key %"PRIu32, key.id);
      continue;
    }

-    key.id = key_id;
-    key.val = MallocArray(char, key.len);
-    memcpy(key.val, keyval, key.len);
    ARR_AppendElement(keys, &key);
  }

@@ -214,7 +275,7 @@ KEY_Reload(void)
  /* Check for duplicates */
  for (i = 1; i < ARR_GetSize(keys); i++) {
    if (get_key(i - 1)->id == get_key(i)->id)
-      LOG(LOGS_WARN, LOGF_Keys, "Detected duplicate key %"PRIu32, get_key(i - 1)->id);
+      LOG(LOGS_WARN, "Detected duplicate key %"PRIu32, get_key(i - 1)->id);
  }

  /* Erase any passwords from stack */
@@ -292,6 +353,30 @@ KEY_GetAuthDelay(uint32_t key_id)

 /* ================================================== */

+int
+KEY_GetAuthLength(uint32_t key_id)
+{
+  unsigned char buf[MAX_HASH_LENGTH];
+  Key *key;
+
+  key = get_key_by_id(key_id);
+
+  if (!key)
+    return 0;
+
+  switch (key->class) {
+    case NTP_MAC:
+      return HSH_Hash(key->data.ntp_mac.hash_id, buf, 0, buf, 0, buf, sizeof (buf));
+    case CMAC:
+      return CMC_Hash(key->data.cmac, buf, 0, buf, sizeof (buf));
+    default:
+      assert(0);
+      return 0;
+  }
+}
+
+/* ================================================== */
+
 int
 KEY_CheckKeyLength(uint32_t key_id)
 {
@@ -302,14 +387,50 @@ KEY_CheckKeyLength(uint32_t key_id)
  if (!key)
    return 0;

-  return key->len >= MIN_SECURE_KEY_LENGTH;
+  switch (key->class) {
+    case NTP_MAC:
+      return key->data.ntp_mac.length >= MIN_SECURE_KEY_LENGTH;
+    default:
+      return 1;
+  }
+}
+
+/* ================================================== */
+
+static int
+generate_auth(Key *key, const unsigned char *data, int data_len,
+              unsigned char *auth, int auth_len)
+{
+  switch (key->class) {
+    case NTP_MAC:
+      return HSH_Hash(key->data.ntp_mac.hash_id, key->data.ntp_mac.value,
+                      key->data.ntp_mac.length, data, data_len, auth, auth_len);
+    case CMAC:
+      return CMC_Hash(key->data.cmac, data, data_len, auth, auth_len);
+    default:
+      return 0;
+  }
+}
+
+/* ================================================== */
+
+static int
+check_auth(Key *key, const unsigned char *data, int data_len,
+           const unsigned char *auth, int auth_len, int trunc_len)
+{
+  unsigned char buf[MAX_HASH_LENGTH];
+  int hash_len;
+
+  hash_len = generate_auth(key, data, data_len, buf, sizeof (buf));
+
+  return MIN(hash_len, trunc_len) == auth_len && !memcmp(buf, auth, auth_len);
 }

 /* ================================================== */

 int
 KEY_GenerateAuth(uint32_t key_id, const unsigned char *data, int data_len,
-    unsigned char *auth, int auth_len)
+                 unsigned char *auth, int auth_len)
 {
  Key *key;

@@ -318,15 +439,14 @@ KEY_GenerateAuth(uint32_t key_id, const unsigned char *data, int data_len,
  if (!key)
    return 0;

-  return UTI_GenerateNTPAuth(key->hash_id, (unsigned char *)key->val,
-                             key->len, data, data_len, auth, auth_len);
+  return generate_auth(key, data, data_len, auth, auth_len);
 }

 /* ================================================== */

 int
 KEY_CheckAuth(uint32_t key_id, const unsigned char *data, int data_len,
-    const unsigned char *auth, int auth_len)
+              const unsigned char *auth, int auth_len, int trunc_len)
 {
  Key *key;

@@ -335,6 +455,5 @@ KEY_CheckAuth(uint32_t key_id, const unsigned char *data, int data_len,
  if (!key)
    return 0;

-  return UTI_CheckNTPAuth(key->hash_id, (unsigned char *)key->val,
-                          key->len, data, data_len, auth, auth_len);
+  return check_auth(key, data, data_len, auth, auth_len, trunc_len);
 }
--- a/keys.h
+++ b/keys.h
@@ -37,11 +37,12 @@ extern void KEY_Reload(void);
 extern int KEY_GetKey(uint32_t key_id, char **key, int *len);
 extern int KEY_KeyKnown(uint32_t key_id);
 extern int KEY_GetAuthDelay(uint32_t key_id);
+extern int KEY_GetAuthLength(uint32_t key_id);
 extern int KEY_CheckKeyLength(uint32_t key_id);

 extern int KEY_GenerateAuth(uint32_t key_id, const unsigned char *data,
    int data_len, unsigned char *auth, int auth_len);
-extern int KEY_CheckAuth(uint32_t key_id, const unsigned char *data,
-    int data_len, const unsigned char *auth, int auth_len);
+extern int KEY_CheckAuth(uint32_t key_id, const unsigned char *data, int data_len,
+                         const unsigned char *auth, int auth_len, int trunc_len);

 #endif /* GOT_KEYS_H */
--- a/local.c
+++ b/local.c
@@ -106,40 +106,47 @@ static double max_clock_error;
   under 1s of busy waiting. */
 #define NITERS 100

+#define NSEC_PER_SEC 1000000000
+
 static void
 calculate_sys_precision(void)
 {
-  struct timeval tv, old_tv;
-  int dusec, best_dusec;
-  int iters;
+  struct timespec ts, old_ts;
+  int iters, diff, best;

-  gettimeofday(&old_tv, NULL);
-  best_dusec = 1000000; /* Assume we must be better than a second */
+  LCL_ReadRawTime(&old_ts);
+
+  /* Assume we must be better than a second */
+  best = NSEC_PER_SEC;
  iters = 0;
+
  do {
-    gettimeofday(&tv, NULL);
-    dusec = 1000000*(tv.tv_sec - old_tv.tv_sec) + (tv.tv_usec - old_tv.tv_usec);
-    old_tv = tv;
-    if (dusec > 0)  {
-      if (dusec < best_dusec) {
-        best_dusec = dusec;
-      }
+    LCL_ReadRawTime(&ts);
+
+    diff = NSEC_PER_SEC * (ts.tv_sec - old_ts.tv_sec) + (ts.tv_nsec - old_ts.tv_nsec);
+
+    old_ts = ts;
+    if (diff > 0) {
+      if (diff < best)
+        best = diff;
      iters++;
    }
  } while (iters < NITERS);

-  assert(best_dusec > 0);
+  assert(best > 0);

-  precision_quantum = best_dusec * 1.0e-6;
+  precision_quantum = 1.0e-9 * best;

  /* Get rounded log2 value of the measured precision */
  precision_log = 0;
-  while (best_dusec < 707107) {
+  while (best < 707106781) {
    precision_log--;
-    best_dusec *= 2;
+    best *= 2;
  }

-  DEBUG_LOG(LOGF_Local, "Clock precision %.9f (%d)", precision_quantum, precision_log);
+  assert(precision_log >= -30);
+
+  DEBUG_LOG("Clock precision %.9f (%d)", precision_quantum, precision_log);
 }

 /* ================================================== */
@@ -278,7 +285,7 @@ LCL_IsFirstParameterChangeHandler(LCL_ParameterChangeHandler handler)
 /* ================================================== */

 static void
-invoke_parameter_change_handlers(struct timeval *raw, struct timeval *cooked,
+invoke_parameter_change_handlers(struct timespec *raw, struct timespec *cooked,
                                 double dfreq, double doffset,
                                 LCL_ChangeType change_type)
 {
@@ -345,23 +352,29 @@ void LCL_RemoveDispersionNotifyHandler(LCL_DispersionNotifyHandler handler, void
 }

 /* ================================================== */
-/* At the moment, this is just gettimeofday(), because
-   I can't think of a Unix system where it would not be */

 void
-LCL_ReadRawTime(struct timeval *result)
+LCL_ReadRawTime(struct timespec *ts)
 {
-  if (gettimeofday(result, NULL) < 0) {
-    LOG_FATAL(LOGF_Local, "gettimeofday() failed");
-  }
+#if HAVE_CLOCK_GETTIME
+  if (clock_gettime(CLOCK_REALTIME, ts) < 0)
+    LOG_FATAL("clock_gettime() failed : %s", strerror(errno));
+#else
+  struct timeval tv;
+
+  if (gettimeofday(&tv, NULL) < 0)
+    LOG_FATAL("gettimeofday() failed : %s", strerror(errno));
+
+  UTI_TimevalToTimespec(&tv, ts);
+#endif
 }

 /* ================================================== */

 void
-LCL_ReadCookedTime(struct timeval *result, double *err)
+LCL_ReadCookedTime(struct timespec *result, double *err)
 {
-  struct timeval raw;
+  struct timespec raw;

  LCL_ReadRawTime(&raw);
  LCL_CookTime(&raw, result, err);
@@ -370,18 +383,18 @@ LCL_ReadCookedTime(struct timeval *result, double *err)
 /* ================================================== */

 void
-LCL_CookTime(struct timeval *raw, struct timeval *cooked, double *err)
+LCL_CookTime(struct timespec *raw, struct timespec *cooked, double *err)
 {
  double correction;

  LCL_GetOffsetCorrection(raw, &correction, err);
-  UTI_AddDoubleToTimeval(raw, correction, cooked);
+  UTI_AddDoubleToTimespec(raw, correction, cooked);
 }

 /* ================================================== */

 void
-LCL_GetOffsetCorrection(struct timeval *raw, double *correction, double *err)
+LCL_GetOffsetCorrection(struct timespec *raw, double *correction, double *err)
 {
  /* Call system specific driver to get correction */
  (*drv_offset_convert)(raw, correction, err);
@@ -413,7 +426,7 @@ clamp_freq(double freq)
  if (freq <= max_freq_ppm && freq >= -max_freq_ppm)
    return freq;

-  LOG(LOGS_WARN, LOGF_Local, "Frequency %.1f ppm exceeds allowed maximum", freq);
+  LOG(LOGS_WARN, "Frequency %.1f ppm exceeds allowed maximum", freq);

  return CLAMP(-max_freq_ppm, freq, max_freq_ppm);
 }
@@ -421,13 +434,13 @@ clamp_freq(double freq)
 /* ================================================== */

 static int
-check_offset(struct timeval *now, double offset)
+check_offset(struct timespec *now, double offset)
 {
  /* Check if the time will be still sane with accumulated offset */
  if (UTI_IsTimeOffsetSane(now, -offset))
      return 1;

-  LOG(LOGS_WARN, LOGF_Local, "Adjustment of %.1f seconds is invalid", -offset);
+  LOG(LOGS_WARN, "Adjustment of %.1f seconds is invalid", -offset);
  return 0;
 }

@@ -439,7 +452,7 @@ check_offset(struct timeval *now, double offset)
 void
 LCL_SetAbsoluteFrequency(double afreq_ppm)
 {
-  struct timeval raw, cooked;
+  struct timespec raw, cooked;
  double dfreq;
  
  afreq_ppm = clamp_freq(afreq_ppm);
@@ -470,7 +483,7 @@ LCL_SetAbsoluteFrequency(double afreq_ppm)
 void
 LCL_AccumulateDeltaFrequency(double dfreq)
 {
-  struct timeval raw, cooked;
+  struct timespec raw, cooked;
  double old_freq_ppm;

  old_freq_ppm = current_freq_ppm;
@@ -499,7 +512,7 @@ LCL_AccumulateDeltaFrequency(double dfreq)
 void
 LCL_AccumulateOffset(double offset, double corr_rate)
 {
-  struct timeval raw, cooked;
+  struct timespec raw, cooked;

  /* In this case, the cooked time to be passed to the notify clients
     has to be the cooked time BEFORE the change was made */
@@ -521,7 +534,7 @@ LCL_AccumulateOffset(double offset, double corr_rate)
 int
 LCL_ApplyStepOffset(double offset)
 {
-  struct timeval raw, cooked;
+  struct timespec raw, cooked;

  /* In this case, the cooked time to be passed to the notify clients
     has to be the cooked time BEFORE the change was made */
@@ -533,7 +546,7 @@ LCL_ApplyStepOffset(double offset)
      return 0;

  if (!(*drv_apply_step_offset)(offset)) {
-    LOG(LOGS_ERR, LOGF_Local, "Could not step clock");
+    LOG(LOGS_ERR, "Could not step system clock");
    return 0;
  }

@@ -549,7 +562,7 @@ LCL_ApplyStepOffset(double offset)
 /* ================================================== */

 void
-LCL_NotifyExternalTimeStep(struct timeval *raw, struct timeval *cooked,
+LCL_NotifyExternalTimeStep(struct timespec *raw, struct timespec *cooked,
    double offset, double dispersion)
 {
  /* Dispatch to all handlers */
@@ -563,7 +576,7 @@ LCL_NotifyExternalTimeStep(struct timeval *raw, struct timeval *cooked,
 void
 LCL_NotifyLeap(int leap)
 {
-  struct timeval raw, cooked;
+  struct timespec raw, cooked;

  LCL_ReadRawTime(&raw);
  LCL_CookTime(&raw, &cooked, NULL);
@@ -580,7 +593,7 @@ LCL_NotifyLeap(int leap)
 void
 LCL_AccumulateFrequencyAndOffset(double dfreq, double doffset, double corr_rate)
 {
-  struct timeval raw, cooked;
+  struct timespec raw, cooked;
  double old_freq_ppm;

  LCL_ReadRawTime(&raw);
@@ -600,7 +613,7 @@ LCL_AccumulateFrequencyAndOffset(double dfreq, double doffset, double corr_rate)

  current_freq_ppm = clamp_freq(current_freq_ppm);

-  DEBUG_LOG(LOGF_Local, "old_freq=%.3fppm new_freq=%.3fppm offset=%.6fsec",
+  DEBUG_LOG("old_freq=%.3fppm new_freq=%.3fppm offset=%.6fsec",
      old_freq_ppm, current_freq_ppm, doffset);

  /* Call the system-specific driver for setting the frequency */
@@ -647,7 +660,7 @@ lcl_RegisterSystemDrivers(lcl_ReadFrequencyDriver read_freq,

  current_freq_ppm = (*drv_read_freq)();

-  DEBUG_LOG(LOGF_Local, "Local freq=%.3fppm", current_freq_ppm);
+  DEBUG_LOG("Local freq=%.3fppm", current_freq_ppm);
 }

 /* ================================================== */
@@ -657,7 +670,7 @@ lcl_RegisterSystemDrivers(lcl_ReadFrequencyDriver read_freq,
 int
 LCL_MakeStep(void)
 {
-  struct timeval raw;
+  struct timespec raw;
  double correction;

  LCL_ReadRawTime(&raw);
@@ -671,7 +684,7 @@ LCL_MakeStep(void)
  if (!LCL_ApplyStepOffset(-correction))
    return 0;

-  LOG(LOGS_WARN, LOGF_Local, "System clock was stepped by %.6f seconds", correction);
+  LOG(LOGS_WARN, "System clock was stepped by %.6f seconds", correction);

  return 1;
 }
@@ -687,10 +700,10 @@ LCL_CanSystemLeap(void)
 /* ================================================== */

 void
-LCL_SetSystemLeap(int leap)
+LCL_SetSystemLeap(int leap, int tai_offset)
 {
  if (drv_set_leap) {
-    (drv_set_leap)(leap);
+    (drv_set_leap)(leap, tai_offset);
  }
 }

--- a/local.h
+++ b/local.h
@@ -31,9 +31,8 @@

 #include "sysincl.h"

-/* Read the system clock.  This is analogous to gettimeofday(),
-   but with the timezone information ignored */
-extern void LCL_ReadRawTime(struct timeval *);
+/* Read the system clock */
+extern void LCL_ReadRawTime(struct timespec *ts);

 /* Read the system clock, corrected according to all accumulated
   drifts and uncompensated offsets.
@@ -44,15 +43,15 @@ extern void LCL_ReadRawTime(struct timeval *);
   adjtime()-like interface to correct offsets, and to adjust the
   frequency), we must correct the raw time to get this value */

-extern void LCL_ReadCookedTime(struct timeval *t, double *err);
+extern void LCL_ReadCookedTime(struct timespec *ts, double *err);

 /* Convert raw time to cooked. */
-extern void LCL_CookTime(struct timeval *raw, struct timeval *cooked, double *err);
+extern void LCL_CookTime(struct timespec *raw, struct timespec *cooked, double *err);

 /* Read the current offset between the system clock and true time
   (i.e. 'cooked' - 'raw') (in seconds). */

-extern void LCL_GetOffsetCorrection(struct timeval *raw, double *correction, double *err);
+extern void LCL_GetOffsetCorrection(struct timespec *raw, double *correction, double *err);

 /* Type of routines that may be invoked as callbacks when there is a
   change to the frequency or offset.
@@ -79,7 +78,7 @@ typedef enum {
 } LCL_ChangeType;

 typedef void (*LCL_ParameterChangeHandler)
-     (struct timeval *raw, struct timeval *cooked,
+     (struct timespec *raw, struct timespec *cooked,
      double dfreq,
      double doffset,
      LCL_ChangeType change_type,
@@ -163,7 +162,7 @@ extern int LCL_ApplyStepOffset(double offset);

 /* Routine to invoke notify handlers on an unexpected time jump
   in system clock */
-extern void LCL_NotifyExternalTimeStep(struct timeval *raw, struct timeval *cooked,
+extern void LCL_NotifyExternalTimeStep(struct timespec *raw, struct timespec *cooked,
    double offset, double dispersion);

 /* Routine to invoke notify handlers on leap second when the system clock
@@ -202,10 +201,11 @@ extern int LCL_MakeStep(void);
   does something */
 extern int LCL_CanSystemLeap(void);

-/* Routine to set the system clock to correct itself for a leap second if
-   supported.  Leap second will be inserted at the end of the day if the
-   argument is positive, deleted if negative, and zero resets the setting. */
-extern void LCL_SetSystemLeap(int leap);
+/* Routine to set the system clock to correct itself for a leap second and also
+   set its TAI-UTC offset.  If supported, leap second will be inserted at the
+   end of the day if the argument is positive, deleted if negative, and zero
+   resets the setting. */
+extern void LCL_SetSystemLeap(int leap, int tai_offset);

 /* Routine to set a frequency correction (in ppm) that should be applied
   to local clock to compensate for temperature changes.  A positive
--- a/localp.h
+++ b/localp.h
@@ -52,10 +52,10 @@ typedef int (*lcl_ApplyStepOffsetDriver)(double offset);
 /* System driver to convert a raw time to an adjusted (cooked) time.
   The number of seconds returned in 'corr' have to be added to the
   raw time to get the corrected time */
-typedef void (*lcl_OffsetCorrectionDriver)(struct timeval *raw, double *corr, double *err);
+typedef void (*lcl_OffsetCorrectionDriver)(struct timespec *raw, double *corr, double *err);

-/* System driver to schedule leap second */
-typedef void (*lcl_SetLeapDriver)(int leap);
+/* System driver to schedule leap seconds and set TAI-UTC offset */
+typedef void (*lcl_SetLeapDriver)(int leap, int tai_offset);

 /* System driver to set the synchronisation status */
 typedef void (*lcl_SetSyncStatusDriver)(int synchronised, double est_error, double max_error);
--- a/logging.c
+++ b/logging.c
@@ -3,7 +3,7 @@

 **********************************************************************
 * Copyright (C) Richard P. Curnow  1997-2003
- * Copyright (C) Miroslav Lichvar  2011-2014
+ * Copyright (C) Miroslav Lichvar  2011-2014, 2018
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
@@ -29,25 +29,24 @@

 #include "sysincl.h"

+#include <syslog.h>
+
 #include "conf.h"
 #include "logging.h"
 #include "util.h"

 /* This is used by DEBUG_LOG macro */
-int log_debug_enabled = 0;
+LOG_Severity log_min_severity = LOGS_INFO;

 /* ================================================== */
 /* Flag indicating we have initialised */
 static int initialised = 0;

+static FILE *file_log = NULL;
 static int system_log = 0;

 static int parent_fd = 0;

-#define DEBUG_LEVEL_PRINT_FUNCTION 2
-#define DEBUG_LEVEL_PRINT_DEBUG 2
-static int debug_level = 0;
-
 struct LogFile {
  const char *name;
  const char *banner;
@@ -69,6 +68,7 @@ void
 LOG_Initialise(void)
 {
  initialised = 1;
+  LOG_OpenFileLog(NULL);
 }

 /* ================================================== */
@@ -77,9 +77,11 @@ LOG_Initialise(void)
 void
 LOG_Finalise(void)
 {
-  if (system_log) {
+  if (system_log)
    closelog();
-  }
+
+  if (file_log)
+    fclose(file_log);

  LOG_CycleLogFiles();

@@ -112,8 +114,8 @@ static void log_message(int fatal, LOG_Severity severity, const char *message)
        assert(0);
    }
    syslog(priority, fatal ? "Fatal error : %s" : "%s", message);
-  } else {
-    fprintf(stderr, fatal ? "Fatal error : %s\n" : "%s\n", message);
+  } else if (file_log) {
+    fprintf(file_log, fatal ? "Fatal error : %s\n" : "%s\n", message);
  }
 }

@@ -121,25 +123,26 @@ static void log_message(int fatal, LOG_Severity severity, const char *message)

 void LOG_Message(LOG_Severity severity,
 #if DEBUG > 0
-                 LOG_Facility facility, int line_number,
-                 const char *filename, const char *function_name,
+                 int line_number, const char *filename, const char *function_name,
 #endif
                 const char *format, ...)
 {
  char buf[2048];
  va_list other_args;
  time_t t;
-  struct tm stm;
+  struct tm *tm;

-  if (!system_log) {
+  if (!system_log && file_log && severity >= log_min_severity) {
    /* Don't clutter up syslog with timestamps and internal debugging info */
    time(&t);
-    stm = *gmtime(&t);
-    strftime(buf, sizeof(buf), "%Y-%m-%dT%H:%M:%SZ", &stm);
-    fprintf(stderr, "%s ", buf);
+    tm = gmtime(&t);
+    if (tm) {
+      strftime(buf, sizeof (buf), "%Y-%m-%dT%H:%M:%SZ", tm);
+      fprintf(file_log, "%s ", buf);
+    }
 #if DEBUG > 0
-    if (debug_level >= DEBUG_LEVEL_PRINT_FUNCTION)
-      fprintf(stderr, "%s:%d:(%s) ", filename, line_number, function_name);
+    if (log_min_severity <= LOGS_DEBUG)
+      fprintf(file_log, "%s:%d:(%s) ", filename, line_number, function_name);
 #endif
  }

@@ -152,28 +155,52 @@ void LOG_Message(LOG_Severity severity,
    case LOGS_INFO:
    case LOGS_WARN:
    case LOGS_ERR:
-      log_message(0, severity, buf);
+      if (severity >= log_min_severity)
+        log_message(0, severity, buf);
      break;
    case LOGS_FATAL:
-      log_message(1, severity, buf);
+      if (severity >= log_min_severity)
+        log_message(1, severity, buf);

-      /* With syslog, send the message also to the grandparent
-         process or write it to stderr if not detached */
-      if (system_log) {
-        if (parent_fd > 0) {
-          if (write(parent_fd, buf, strlen(buf) + 1) < 0)
-            ; /* Not much we can do here */
-        } else if (parent_fd == 0) {
-          system_log = 0;
-          log_message(1, severity, buf);
-        }
+      /* Send the message also to the foreground process if it is
+         still running, or stderr if it is still open */
+      if (parent_fd > 0) {
+        if (write(parent_fd, buf, strlen(buf) + 1) < 0)
+          ; /* Not much we can do here */
+      } else if (system_log && parent_fd == 0) {
+        system_log = 0;
+        log_message(1, severity, buf);
      }
+      exit(1);
      break;
    default:
      assert(0);
  }
 }

+/* ================================================== */
+
+void
+LOG_OpenFileLog(const char *log_file)
+{
+  FILE *f;
+
+  if (log_file) {
+    f = UTI_OpenFile(NULL, log_file, NULL, 'A', 0640);
+  } else {
+    f = stderr;
+  }
+
+  /* Enable line buffering */
+  setvbuf(f, NULL, _IOLBF, BUFSIZ);
+
+  if (file_log && file_log != stderr)
+    fclose(file_log);
+
+  file_log = f;
+}
+
+
 /* ================================================== */

 void
@@ -185,12 +212,10 @@ LOG_OpenSystemLog(void)

 /* ================================================== */

-void LOG_SetDebugLevel(int level)
+void LOG_SetMinSeverity(LOG_Severity severity)
 {
-  debug_level = level;
-  if (level >= DEBUG_LEVEL_PRINT_DEBUG) {
-    log_debug_enabled = 1;
-  }
+  /* Don't print any debug messages in a non-debug build */
+  log_min_severity = CLAMP(DEBUG > 0 ? LOGS_DEBUG : LOGS_INFO, severity, LOGS_FATAL);
 }

 /* ================================================== */
@@ -199,6 +224,8 @@ void
 LOG_SetParentFd(int fd)
 {
  parent_fd = fd;
+  if (file_log == stderr)
+    file_log = NULL;
 }

 /* ================================================== */
@@ -238,18 +265,20 @@ LOG_FileWrite(LOG_FileID id, const char *format, ...)
    return;

  if (!logfiles[id].file) {
-    char filename[512];
+    char *logdir = CNF_GetLogDir();

-    if (snprintf(filename, sizeof(filename), "%s/%s.log",
-          CNF_GetLogDir(), logfiles[id].name) >= sizeof(filename) ||
-        !(logfiles[id].file = fopen(filename, "a"))) {
-      LOG(LOGS_WARN, LOGF_Refclock, "Couldn't open logfile %s for update", filename);
+    if (logdir[0] == '\0') {
+      LOG(LOGS_WARN, "logdir not specified");
      logfiles[id].name = NULL;
      return;
    }

-    /* Close on exec */
-    UTI_FdSetCloexec(fileno(logfiles[id].file));
+    logfiles[id].file = UTI_OpenFile(logdir, logfiles[id].name, ".log", 'a', 0644);
+    if (!logfiles[id].file) {
+      /* Disable the log */
+      logfiles[id].name = NULL;
+      return;
+    }
  }

  banner = CNF_GetLogBanner();
@@ -257,7 +286,7 @@ LOG_FileWrite(LOG_FileID id, const char *format, ...)
    char bannerline[256];
    int i, bannerlen;

-    bannerlen = strlen(logfiles[id].banner);
+    bannerlen = MIN(strlen(logfiles[id].banner), sizeof (bannerline) - 1);

    for (i = 0; i < bannerlen; i++)
      bannerline[i] = '=';
--- a/logging.h
+++ b/logging.h
@@ -31,9 +31,6 @@

 #include "sysincl.h"

-/* Flag indicating whether debug messages are logged */
-extern int log_debug_enabled;
-
 /* Line logging macros.  If the compiler is GNU C, we take advantage of
   being able to get the function name also. */

@@ -46,76 +43,38 @@ extern int log_debug_enabled;
 #endif

 #if DEBUG > 0
-#define LOG_MESSAGE(severity, facility, ...) \
-  LOG_Message(severity, facility, __LINE__, __FILE__, FUNCTION_NAME, __VA_ARGS__);
+#define LOG_MESSAGE(severity, ...) \
+  LOG_Message(severity, __LINE__, __FILE__, FUNCTION_NAME, __VA_ARGS__)
 #else
-#define LOG_MESSAGE(severity, facility, ...) \
-  LOG_Message(severity, __VA_ARGS__);
+#define LOG_MESSAGE(severity, ...) \
+  LOG_Message(severity, __VA_ARGS__)
 #endif

-#define DEBUG_LOG(facility, ...) \
+#define DEBUG_LOG(...) \
  do { \
-    if (DEBUG && log_debug_enabled) \
-      LOG_MESSAGE(LOGS_DEBUG, facility, __VA_ARGS__); \
+    if (DEBUG && log_min_severity == LOGS_DEBUG) \
+      LOG_MESSAGE(LOGS_DEBUG, __VA_ARGS__); \
  } while (0)

-#define LOG_FATAL(facility, ...) \
+#define LOG_FATAL(...) \
  do { \
-    LOG_MESSAGE(LOGS_FATAL, facility, __VA_ARGS__); \
+    LOG_MESSAGE(LOGS_FATAL, __VA_ARGS__); \
    exit(1); \
  } while (0)

-#define LOG(severity, facility, ...) LOG_MESSAGE(severity, facility, __VA_ARGS__)
+#define LOG(severity, ...) LOG_MESSAGE(severity, __VA_ARGS__)

 /* Definition of severity */
 typedef enum {
-  LOGS_INFO,
+  LOGS_DEBUG = -1,
+  LOGS_INFO = 0,
  LOGS_WARN,
  LOGS_ERR,
  LOGS_FATAL,
-  LOGS_DEBUG
 } LOG_Severity;

-/* Definition of facility.  Each message is tagged with who generated
-   it, so that the user can customise what level of reporting he gets
-   for each area of the software */
-typedef enum {
-  LOGF_Reference,
-  LOGF_NtpIO,
-  LOGF_NtpCore,
-  LOGF_NtpSources,
-  LOGF_Scheduler,
-  LOGF_SourceStats,
-  LOGF_Sources,
-  LOGF_Local,
-  LOGF_Util,
-  LOGF_Main,
-  LOGF_Memory,
-  LOGF_Client,
-  LOGF_ClientLog,
-  LOGF_Configure,
-  LOGF_CmdMon,
-  LOGF_Acquire,
-  LOGF_Manual,
-  LOGF_Keys,
-  LOGF_Logging,
-  LOGF_Nameserv,
-  LOGF_PrivOps,
-  LOGF_Rtc,
-  LOGF_Regress,
-  LOGF_Sys,
-  LOGF_SysGeneric,
-  LOGF_SysLinux,
-  LOGF_SysMacOSX,
-  LOGF_SysNetBSD,
-  LOGF_SysSolaris,
-  LOGF_SysTimex,
-  LOGF_SysWinnt,
-  LOGF_TempComp,
-  LOGF_RtcLinux,
-  LOGF_Refclock,
-  LOGF_Smooth,
-} LOG_Facility;
+/* Minimum severity of messages to be logged */
+extern LOG_Severity log_min_severity;

 /* Init function */
 extern void LOG_Initialise(void);
@@ -125,26 +84,26 @@ extern void LOG_Finalise(void);

 /* Line logging function */
 #if DEBUG > 0
-FORMAT_ATTRIBUTE_PRINTF(6, 7)
-extern void LOG_Message(LOG_Severity severity, LOG_Facility facility,
-                        int line_number, const char *filename,
+FORMAT_ATTRIBUTE_PRINTF(5, 6)
+extern void LOG_Message(LOG_Severity severity, int line_number, const char *filename,
                        const char *function_name, const char *format, ...);
 #else
 FORMAT_ATTRIBUTE_PRINTF(2, 3)
 extern void LOG_Message(LOG_Severity severity, const char *format, ...);
 #endif

-/* Set debug level:
-   0, 1 - only non-debug messages are logged
-   2    - debug messages are logged too, all messages are prefixed with
-          filename, line, and function name
-   */
-extern void LOG_SetDebugLevel(int level);
+/* Set the minimum severity of a message to be logged or printed to terminal.
+   If the severity is LOGS_DEBUG and DEBUG is enabled, all messages will be
+   prefixed with the filename, line number, and function name. */
+extern void LOG_SetMinSeverity(LOG_Severity severity);
+
+/* Log messages to a file instead of stderr, or stderr again if NULL */
+extern void LOG_OpenFileLog(const char *log_file);

 /* Log messages to syslog instead of stderr */
 extern void LOG_OpenSystemLog(void);

-/* Send fatal message also to the foreground process */
+/* Stop using stderr and send fatal message to the foreground process */
 extern void LOG_SetParentFd(int fd);

 /* Close the pipe to the foreground process so it can exit */
--- a/main.c
+++ b/main.c
@@ -4,7 +4,7 @@
 **********************************************************************
 * Copyright (C) Richard P. Curnow  1997-2003
 * Copyright (C) John G. Hasler  2009
- * Copyright (C) Miroslav Lichvar  2012-2015
+ * Copyright (C) Miroslav Lichvar  2012-2018
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
@@ -35,8 +35,13 @@
 #include "local.h"
 #include "sys.h"
 #include "ntp_io.h"
+#include "ntp_signd.h"
 #include "ntp_sources.h"
 #include "ntp_core.h"
+#include "nts_ke_client.h"
+#include "nts_ke_server.h"
+#include "nts_ntp_server.h"
+#include "socket.h"
 #include "sources.h"
 #include "sourcestats.h"
 #include "reference.h"
@@ -85,8 +90,12 @@ static void
 delete_pidfile(void)
 {
  const char *pidfile = CNF_GetPidFile();
-  /* Don't care if this fails, there's not a lot we can do */
-  unlink(pidfile);
+
+  if (!pidfile[0])
+    return;
+
+  if (!UTI_RemoveFile(NULL, pidfile, NULL))
+    ;
 }

 /* ================================================== */
@@ -96,7 +105,7 @@ MAI_CleanupAndExit(void)
 {
  if (!initialised) exit(exit_status);
  
-  if (CNF_GetDumpOnExit()) {
+  if (CNF_GetDumpDir()[0] != '\0') {
    SRC_DumpSources();
  }

@@ -107,11 +116,16 @@ MAI_CleanupAndExit(void)
  TMC_Finalise();
  MNL_Finalise();
  CLG_Finalise();
+  NKC_Finalise();
+  NKS_Finalise();
+  NNS_Finalise();
+  NSD_Finalise();
  NSR_Finalise();
  SST_Finalise();
  NCR_Finalise();
  NIO_Finalise();
  CAM_Finalise();
+  SCK_Finalise();
  KEY_Finalise();
  RCL_Finalise();
  SRC_Finalise();
@@ -125,9 +139,8 @@ MAI_CleanupAndExit(void)
  delete_pidfile();
  
  CNF_Finalise();
-  LOG_Finalise();
-
  HSH_Finalise();
+  LOG_Finalise();

  exit(exit_status);
 }
@@ -143,6 +156,16 @@ signal_cleanup(int x)

 /* ================================================== */

+static void
+quit_timeout(void *arg)
+{
+  /* Return with non-zero status if the clock is not synchronised */
+  exit_status = REF_GetOurStratum() >= NTP_MAX_STRATUM;
+  SCH_QuitProgram();
+}
+
+/* ================================================== */
+
 static void
 ntp_source_resolving_end(void)
 {
@@ -156,6 +179,7 @@ ntp_source_resolving_end(void)
    SRC_ReloadSources();
  }

+  SRC_RemoveDumpFiles();
  RTC_StartMeasurements();
  RCL_StartRefclocks();
  NSR_StartSources();
@@ -229,63 +253,54 @@ post_init_rtc_hook(void *anything)
 }

 /* ================================================== */
-/* Return 1 if the process exists on the system. */

-static int
-does_process_exist(int pid)
-{
-  int status;
-  status = getsid(pid);
-  if (status >= 0) {
-    return 1;
-  } else {
-    return 0;
-  }
-}
-
-/* ================================================== */
-
-static int
-maybe_another_chronyd_running(int *other_pid)
+static void
+check_pidfile(void)
 {
  const char *pidfile = CNF_GetPidFile();
  FILE *in;
  int pid, count;
  
-  *other_pid = 0;
+  if (!pidfile[0])
+    return;

-  in = fopen(pidfile, "r");
-  if (!in) return 0;
+  in = UTI_OpenFile(NULL, pidfile, NULL, 'r', 0);
+  if (!in)
+    return;

  count = fscanf(in, "%d", &pid);
  fclose(in);
  
-  if (count != 1) return 0;
+  if (count != 1)
+    return;

-  *other_pid = pid;
-  return does_process_exist(pid);
-  
+  if (getsid(pid) < 0)
+    return;
+
+  LOG_FATAL("Another chronyd may already be running (pid=%d), check %s",
+            pid, pidfile);
 }

 /* ================================================== */

 static void
-write_lockfile(void)
+write_pidfile(void)
 {
  const char *pidfile = CNF_GetPidFile();
  FILE *out;

-  out = fopen(pidfile, "w");
-  if (!out) {
-    LOG_FATAL(LOGF_Main, "could not open lockfile %s for writing", pidfile);
-  } else {
-    fprintf(out, "%d\n", (int)getpid());
-    fclose(out);
-  }
+  if (!pidfile[0])
+    return;
+
+  out = UTI_OpenFile(NULL, pidfile, NULL, 'W', 0644);
+  fprintf(out, "%d\n", (int)getpid());
+  fclose(out);
 }

 /* ================================================== */

+#define DEV_NULL "/dev/null"
+
 static void
 go_daemon(void)
 {
@@ -294,14 +309,14 @@ go_daemon(void)
  /* Create pipe which will the daemon use to notify the grandparent
     when it's initialised or send an error message */
  if (pipe(pipefd)) {
-    LOG_FATAL(LOGF_Logging, "Could not detach, pipe failed : %s", strerror(errno));
+    LOG_FATAL("pipe() failed : %s", strerror(errno));
  }

  /* Does this preserve existing signal handlers? */
  pid = fork();

  if (pid < 0) {
-    LOG_FATAL(LOGF_Logging, "Could not detach, fork failed : %s", strerror(errno));
+    LOG_FATAL("fork() failed : %s", strerror(errno));
  } else if (pid > 0) {
    /* In the 'grandparent' */
    char message[1024];
@@ -312,7 +327,8 @@ go_daemon(void)
    if (r) {
      if (r > 0) {
        /* Print the error message from the child */
-        fprintf(stderr, "%.1024s\n", message);
+        message[sizeof (message) - 1] = '\0';
+        fprintf(stderr, "%s\n", message);
      }
      exit(1);
    } else
@@ -326,7 +342,7 @@ go_daemon(void)
    pid = fork();

    if (pid < 0) {
-      LOG_FATAL(LOGF_Logging, "Could not detach, fork failed : %s", strerror(errno));
+      LOG_FATAL("fork() failed : %s", strerror(errno));
    } else if (pid > 0) {
      exit(0); /* In the 'parent' */
    } else {
@@ -334,7 +350,7 @@ go_daemon(void)

      /* Change current directory to / */
      if (chdir("/") < 0) {
-        LOG_FATAL(LOGF_Logging, "Could not chdir to / : %s", strerror(errno));
+        LOG_FATAL("chdir() failed : %s", strerror(errno));
      }

      /* Don't keep stdin/out/err from before. But don't close
@@ -345,148 +361,207 @@ go_daemon(void)
      }

      LOG_SetParentFd(pipefd[1]);
+
+      /* Open /dev/null as new stdin/out/err */
+      errno = 0;
+      if (open(DEV_NULL, O_RDONLY) != STDIN_FILENO ||
+          open(DEV_NULL, O_WRONLY) != STDOUT_FILENO ||
+          open(DEV_NULL, O_RDWR) != STDERR_FILENO)
+        LOG_FATAL("Could not open %s : %s", DEV_NULL, strerror(errno));
    }
  }
 }

 /* ================================================== */

+static void
+print_help(const char *progname)
+{
+      printf("Usage: %s [-4|-6] [-n|-d] [-q|-Q] [-r] [-R] [-s] [-t TIMEOUT] [-f FILE|COMMAND...]\n",
+             progname);
+}
+
+/* ================================================== */
+
+static void
+print_version(void)
+{
+  printf("chronyd (chrony) version %s (%s)\n", CHRONY_VERSION, CHRONYD_FEATURES);
+}
+
+/* ================================================== */
+
+static int
+parse_int_arg(const char *arg)
+{
+  int i;
+
+  if (sscanf(arg, "%d", &i) != 1)
+    LOG_FATAL("Invalid argument %s", arg);
+  return i;
+}
+
+/* ================================================== */
+
 int main
 (int argc, char **argv)
 {
  const char *conf_file = DEFAULT_CONF_FILE;
  const char *progname = argv[0];
-  char *user = NULL;
+  char *user = NULL, *log_file = NULL;
  struct passwd *pw;
-  int debug = 0, nofork = 0, address_family = IPADDR_UNSPEC;
-  int do_init_rtc = 0, restarted = 0;
-  int other_pid;
+  int opt, debug = 0, nofork = 0, address_family = IPADDR_UNSPEC;
+  int do_init_rtc = 0, restarted = 0, client_only = 0, timeout = -1;
  int scfilter_level = 0, lock_memory = 0, sched_priority = 0;
-  int system_log = 1;
+  int clock_control = 1, system_log = 1, log_severity = LOGS_INFO;
  int config_args = 0;

  do_platform_checks();

  LOG_Initialise();

-  /* Parse command line options */
-  while (++argv, (--argc)>0) {
-
-    if (!strcmp("-f", *argv)) {
-      ++argv, --argc;
-      conf_file = *argv;
-    } else if (!strcmp("-P", *argv)) {
-      ++argv, --argc;
-      if (argc == 0 || sscanf(*argv, "%d", &sched_priority) != 1) {
-        LOG_FATAL(LOGF_Main, "Bad scheduler priority");
-      }
-    } else if (!strcmp("-m", *argv)) {
-      lock_memory = 1;
-    } else if (!strcmp("-r", *argv)) {
-      reload = 1;
-    } else if (!strcmp("-R", *argv)) {
-      restarted = 1;
-    } else if (!strcmp("-u", *argv)) {
-      ++argv, --argc;
-      if (argc == 0) {
-        LOG_FATAL(LOGF_Main, "Missing user name");
-      } else {
-        user = *argv;
-      }
-    } else if (!strcmp("-F", *argv)) {
-      ++argv, --argc;
-      if (argc == 0 || sscanf(*argv, "%d", &scfilter_level) != 1)
-        LOG_FATAL(LOGF_Main, "Bad syscall filter level");
-    } else if (!strcmp("-s", *argv)) {
-      do_init_rtc = 1;
-    } else if (!strcmp("-v", *argv) || !strcmp("--version",*argv)) {
-      /* This write to the terminal is OK, it comes before we turn into a daemon */
-      printf("chronyd (chrony) version %s (%s)\n", CHRONY_VERSION, CHRONYD_FEATURES);
+  /* Parse (undocumented) long command-line options */
+  for (optind = 1; optind < argc; optind++) {
+    if (!strcmp("--help", argv[optind])) {
+      print_help(progname);
      return 0;
-    } else if (!strcmp("-n", *argv)) {
-      nofork = 1;
-    } else if (!strcmp("-d", *argv)) {
-      debug++;
-      nofork = 1;
-      system_log = 0;
-    } else if (!strcmp("-q", *argv)) {
-      ref_mode = REF_ModeUpdateOnce;
-      nofork = 1;
-      system_log = 0;
-    } else if (!strcmp("-Q", *argv)) {
-      ref_mode = REF_ModePrintOnce;
-      nofork = 1;
-      system_log = 0;
-    } else if (!strcmp("-4", *argv)) {
-      address_family = IPADDR_INET4;
-    } else if (!strcmp("-6", *argv)) {
-      address_family = IPADDR_INET6;
-    } else if (!strcmp("-h", *argv) || !strcmp("--help", *argv)) {
-      printf("Usage: %s [-4|-6] [-n|-d] [-q|-Q] [-r] [-R] [-s] [-f FILE|COMMAND...]\n",
-             progname);
+    } else if (!strcmp("--version", argv[optind])) {
+      print_version();
      return 0;
-    } else if (*argv[0] == '-') {
-      LOG_FATAL(LOGF_Main, "Unrecognized command line option [%s]", *argv);
-    } else {
-      /* Process remaining arguments and configuration lines */
-      config_args = argc;
-      break;
    }
  }

-  if (getuid() != 0) {
-    /* This write to the terminal is OK, it comes before we turn into a daemon */
-    fprintf(stderr,"Not superuser\n");
-    return 1;
+  optind = 1;
+
+  /* Parse short command-line options */
+  while ((opt = getopt(argc, argv, "46df:F:hl:L:mnP:qQrRst:u:vx")) != -1) {
+    switch (opt) {
+      case '4':
+      case '6':
+        address_family = opt == '4' ? IPADDR_INET4 : IPADDR_INET6;
+        break;
+      case 'd':
+        debug++;
+        nofork = 1;
+        system_log = 0;
+        break;
+      case 'f':
+        conf_file = optarg;
+        break;
+      case 'F':
+        scfilter_level = parse_int_arg(optarg);
+        break;
+      case 'l':
+        log_file = optarg;
+        break;
+      case 'L':
+        log_severity = parse_int_arg(optarg);
+        break;
+      case 'm':
+        lock_memory = 1;
+        break;
+      case 'n':
+        nofork = 1;
+        break;
+      case 'P':
+        sched_priority = parse_int_arg(optarg);
+        break;
+      case 'q':
+        ref_mode = REF_ModeUpdateOnce;
+        nofork = 1;
+        client_only = 0;
+        system_log = 0;
+        break;
+      case 'Q':
+        ref_mode = REF_ModePrintOnce;
+        nofork = 1;
+        client_only = 1;
+        clock_control = 0;
+        system_log = 0;
+        break;
+      case 'r':
+        reload = 1;
+        break;
+      case 'R':
+        restarted = 1;
+        break;
+      case 's':
+        do_init_rtc = 1;
+        break;
+      case 't':
+        timeout = parse_int_arg(optarg);
+        break;
+      case 'u':
+        user = optarg;
+        break;
+      case 'v':
+        print_version();
+        return 0;
+      case 'x':
+        clock_control = 0;
+        break;
+      default:
+        print_help(progname);
+        return opt != 'h';
+    }
  }

+  if (getuid() && !client_only)
+    LOG_FATAL("Not superuser");
+
  /* Turn into a daemon */
  if (!nofork) {
    go_daemon();
  }

-  if (system_log) {
+  if (log_file) {
+    LOG_OpenFileLog(log_file);
+  } else if (system_log) {
    LOG_OpenSystemLog();
  }
  
-  LOG_SetDebugLevel(debug);
+  LOG_SetMinSeverity(debug >= 2 ? LOGS_DEBUG : log_severity);
  
-  LOG(LOGS_INFO, LOGF_Main, "chronyd version %s starting (%s)",
-      CHRONY_VERSION, CHRONYD_FEATURES);
+  LOG(LOGS_INFO, "chronyd version %s starting (%s)", CHRONY_VERSION, CHRONYD_FEATURES);

  DNS_SetAddressFamily(address_family);

-  CNF_Initialise(restarted);
+  CNF_Initialise(restarted, client_only);

  /* Parse the config file or the remaining command line arguments */
+  config_args = argc - optind;
  if (!config_args) {
    CNF_ReadFile(conf_file);
  } else {
-    do {
-      CNF_ParseLine(NULL, config_args - argc + 1, *argv);
-    } while (++argv, --argc);
+    for (; optind < argc; optind++)
+      CNF_ParseLine(NULL, config_args + optind - argc + 1, argv[optind]);
  }

-  /* Check whether another chronyd may already be running.  Do this after
-   * forking, so that message logging goes to the right place (i.e. syslog), in
-   * case this chronyd is being run from a boot script. */
-  if (maybe_another_chronyd_running(&other_pid)) {
-    LOG_FATAL(LOGF_Main, "Another chronyd may already be running (pid=%d), check lockfile (%s)",
-              other_pid, CNF_GetPidFile());
-  }
+  /* Check whether another chronyd may already be running */
+  check_pidfile();

-  /* Write our lockfile to prevent other chronyds running.  This has *GOT* to
-   * be done *AFTER* the daemon-creation fork() */
-  write_lockfile();
+  if (!user)
+    user = CNF_GetUser();
+
+  pw = getpwnam(user);
+  if (!pw)
+    LOG_FATAL("Could not get user/group ID of %s", user);
+
+  /* Create directories for sockets, log files, and dump files */
+  CNF_CreateDirs(pw->pw_uid, pw->pw_gid);
+
+  /* Write our pidfile to prevent other instances from running */
+  write_pidfile();

  PRV_Initialise();
  LCL_Initialise();
  SCH_Initialise();
-  SYS_Initialise();
+  SYS_Initialise(clock_control);
  RTC_Initialise(do_init_rtc);
  SRC_Initialise();
  RCL_Initialise();
  KEY_Initialise();
+  SCK_Initialise();

  /* Open privileged ports before dropping root */
  CAM_Initialise(address_family);
@@ -506,23 +581,17 @@ int main
    SYS_LockMemory();
  }

-  if (!user) {
-    user = CNF_GetUser();
-  }
-
-  if ((pw = getpwnam(user)) == NULL)
-    LOG_FATAL(LOGF_Main, "Could not get %s uid/gid", user);
-
-  /* Create all directories before dropping root */
-  CNF_CreateDirs(pw->pw_uid, pw->pw_gid);
-
-  /* Drop root privileges if the user has non-zero uid or gid */
-  if (pw->pw_uid || pw->pw_gid)
+  /* Drop root privileges if the specified user has a non-zero UID */
+  if (!geteuid() && (pw->pw_uid || pw->pw_gid))
    SYS_DropRoot(pw->pw_uid, pw->pw_gid);

  REF_Initialise();
  SST_Initialise();
  NSR_Initialise();
+  NSD_Initialise();
+  NNS_Initialise();
+  NKS_Initialise(scfilter_level);
+  NKC_Initialise();
  CLG_Initialise();
  MNL_Initialise();
  TMC_Initialise();
@@ -531,12 +600,12 @@ int main
  /* From now on, it is safe to do finalisation on exit */
  initialised = 1;

-  UTI_SetQuitSignalsHandler(signal_cleanup);
+  UTI_SetQuitSignalsHandler(signal_cleanup, 1);

  CAM_OpenUnixSocket();

  if (scfilter_level)
-    SYS_EnableSystemCallFilter(scfilter_level);
+    SYS_EnableSystemCallFilter(scfilter_level, SYS_MAIN_PROCESS);

  if (ref_mode == REF_ModeNormal && CNF_GetInitSources() > 0) {
    ref_mode = REF_ModeInitStepSlew;
@@ -545,6 +614,9 @@ int main
  REF_SetModeEndHandler(reference_mode_end);
  REF_SetMode(ref_mode);

+  if (timeout >= 0)
+    SCH_AddTimeoutByDelay(timeout, quit_timeout, NULL);
+
  if (do_init_rtc) {
    RTC_TimeInit(post_init_rtc_hook, NULL);
  } else {
@@ -555,7 +627,7 @@ int main
     the scheduler. */
  SCH_MainLoop();

-  LOG(LOGS_INFO, LOGF_Main, "chronyd exiting");
+  LOG(LOGS_INFO, "chronyd exiting");

  MAI_CleanupAndExit();

--- a/2
+++ b/2
@@ -36,8 +36,6 @@ cd RELEASES/$subdir || exit 1

 echo $version > version.txt

-sed -i -e "s%@@VERSION@@%${version}%" examples/chrony.spec
-
 ./configure && make -C doc man txt || exit 1

 iconv -f utf-8 -t ascii//TRANSLIT < doc/installation.txt > INSTALL
--- a/manual.c
+++ b/manual.c
@@ -47,7 +47,7 @@ static int enabled = 0;

 /* More recent samples at highest indices */
 typedef struct {
-  struct timeval when; /* This is our 'cooked' time */
+  struct timespec when; /* This is our 'cooked' time */
  double orig_offset; /*+ Not modified by slew samples */
  double offset; /*+ if we are fast of the supplied reference */
  double residual; /*+ regression residual (sign convention given by
@@ -64,8 +64,8 @@ static int n_samples;
 /* ================================================== */

 static void
-slew_samples(struct timeval *raw,
-             struct timeval *cooked, 
+slew_samples(struct timespec *raw,
+             struct timespec *cooked,
             double dfreq,
             double doffset,
             LCL_ChangeType change_type,
@@ -97,7 +97,8 @@ MNL_Finalise(void)
 /* ================================================== */

 static void
-estimate_and_set_system(struct timeval *now, int offset_provided, double offset, long *offset_cs, double *dfreq_ppm, double *new_afreq_ppm)
+estimate_and_set_system(struct timespec *now, int offset_provided, double offset,
+                        double *reg_offset, double *dfreq_ppm, double *new_afreq_ppm)
 {
  double agos[MAX_SAMPLES], offsets[MAX_SAMPLES];
  double b0, b1;
@@ -108,32 +109,26 @@ estimate_and_set_system(struct timeval *now, int offset_provided, double offset,
  int found_freq;
  double slew_by;

+  b0 = offset_provided ? offset : 0.0;
+  b1 = freq = 0.0;
+  found_freq = 0;
+
  if (n_samples > 1) {
    for (i=0; i<n_samples; i++) {
-      UTI_DiffTimevalsToDouble(&agos[i], &samples[n_samples-1].when, &samples[i].when);
+      agos[i] = UTI_DiffTimespecsToDouble(&samples[n_samples - 1].when, &samples[i].when);
      offsets[i] = samples[i].offset;
    }
    
-    RGR_FindBestRobustRegression(agos, offsets, n_samples,
-                                 1.0e-8, /* 0.01ppm easily good enough for this! */
-                                 &b0, &b1, &n_runs, &best_start);
-    
-    
-    /* Ignore b0 from regression; treat offset as being the most
-       recently entered value.  (If the administrator knows he's put
-       an outlier in, he will rerun the settime operation.)   However,
-       the frequency estimate comes from the regression. */
-    
-    freq = -b1;
-    found_freq = 1;
-  } else {
-    if (offset_provided) {
-      b0 = offset;
-    } else {
-      b0 = 0.0;
+    if (RGR_FindBestRobustRegression(agos, offsets, n_samples, 1.0e-8,
+                                     &b0, &b1, &n_runs, &best_start)) {
+      /* Ignore b0 from regression; treat offset as being the most
+         recently entered value.  (If the administrator knows he's put
+         an outlier in, he will rerun the settime operation.)   However,
+         the frequency estimate comes from the regression. */
+      freq = -b1;
+      found_freq = 1;
    }
-    b1 = freq = 0.0;
-    found_freq = 0;
+  } else {
    agos[0] = 0.0;
    offsets[0] = b0;
  }
@@ -145,21 +140,20 @@ estimate_and_set_system(struct timeval *now, int offset_provided, double offset,
  }
  
  if (found_freq) {
-    LOG(LOGS_INFO, LOGF_Manual,
-        "Making a frequency change of %.3f ppm and a slew of %.6f",
+    LOG(LOGS_INFO, "Making a frequency change of %.3f ppm and a slew of %.6f",
        1.0e6 * freq, slew_by);
    
    REF_SetManualReference(now,
                           slew_by,
                           freq, skew);
  } else {
-    LOG(LOGS_INFO, LOGF_Manual, "Making a slew of %.6f", slew_by);
+    LOG(LOGS_INFO, "Making a slew of %.6f", slew_by);
    REF_SetManualReference(now,
                           slew_by,
                           0.0, skew);
  }
  
-  if (offset_cs) *offset_cs = (long)(0.5 + 100.0 * b0);
+  if (reg_offset) *reg_offset = b0;
  if (dfreq_ppm) *dfreq_ppm = 1.0e6 * freq;
  if (new_afreq_ppm) *new_afreq_ppm = LCL_ReadAbsoluteFrequency();
  
@@ -173,9 +167,9 @@ estimate_and_set_system(struct timeval *now, int offset_provided, double offset,
 /* ================================================== */

 int
-MNL_AcceptTimestamp(struct timeval *ts, long *offset_cs, double *dfreq_ppm, double *new_afreq_ppm)
+MNL_AcceptTimestamp(struct timespec *ts, double *reg_offset, double *dfreq_ppm, double *new_afreq_ppm)
 {
-  struct timeval now;
+  struct timespec now;
  double offset, diff;
  int i;

@@ -189,12 +183,12 @@ MNL_AcceptTimestamp(struct timeval *ts, long *offset_cs, double *dfreq_ppm, doub
     return 0;

    if (n_samples) {
-      UTI_DiffTimevalsToDouble(&diff, &now, &samples[n_samples - 1].when);
+      diff = UTI_DiffTimespecsToDouble(&now, &samples[n_samples - 1].when);
      if (diff < MIN_SAMPLE_SEPARATION)
        return 0;
    }

-    UTI_DiffTimevalsToDouble(&offset, &now, ts);
+    offset = UTI_DiffTimespecsToDouble(&now, ts);

    /* Check if buffer full up */
    if (n_samples == MAX_SAMPLES) {
@@ -210,7 +204,7 @@ MNL_AcceptTimestamp(struct timeval *ts, long *offset_cs, double *dfreq_ppm, doub
    samples[n_samples].orig_offset = offset;
    ++n_samples;

-    estimate_and_set_system(&now, 1, offset, offset_cs, dfreq_ppm, new_afreq_ppm);
+    estimate_and_set_system(&now, 1, offset, reg_offset, dfreq_ppm, new_afreq_ppm);

    return 1;

@@ -224,8 +218,8 @@ MNL_AcceptTimestamp(struct timeval *ts, long *offset_cs, double *dfreq_ppm, doub
 /* ================================================== */

 static void
-slew_samples(struct timeval *raw,
-             struct timeval *cooked, 
+slew_samples(struct timespec *raw,
+             struct timespec *cooked,
             double dfreq,
             double doffset,
             LCL_ChangeType change_type,
@@ -239,7 +233,7 @@ slew_samples(struct timeval *raw,
  }

  for (i=0; i<n_samples; i++) {
-    UTI_AdjustTimeval(&samples[i].when, cooked, &samples[i].when, &delta_time,
+    UTI_AdjustTimespec(&samples[i].when, cooked, &samples[i].when, &delta_time,
        dfreq, doffset);
    samples[i].offset += delta_time;
  }
@@ -309,7 +303,7 @@ int
 MNL_DeleteSample(int index)
 {
  int i;
-  struct timeval now;
+  struct timespec now;

  if ((index < 0) || (index >= n_samples)) {
    return 0;
--- a/manual.h
+++ b/manual.h
@@ -33,7 +33,7 @@

 extern void MNL_Initialise(void);
 extern void MNL_Finalise(void);
-extern int MNL_AcceptTimestamp(struct timeval *ts, long *offset_cs, double *dfreq_ppm, double *new_afreq_ppm);
+extern int MNL_AcceptTimestamp(struct timespec *ts, double *reg_offset, double *dfreq_ppm, double *new_afreq_ppm);

 extern void MNL_Enable(void);
 extern void MNL_Disable(void);
--- a/memory.c
+++ b/memory.c
@@ -2,7 +2,7 @@
  chronyd/chronyc - Programs for keeping computer clocks accurate.

 **********************************************************************
- * Copyright (C) Miroslav Lichvar  2014
+ * Copyright (C) Miroslav Lichvar  2014, 2017
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
@@ -37,7 +37,7 @@ Malloc(size_t size)

  r = malloc(size);
  if (!r && size)
-    LOG_FATAL(LOGF_Memory, "Could not allocate memory");
+    LOG_FATAL("Could not allocate memory");

  return r;
 }
@@ -49,11 +49,37 @@ Realloc(void *ptr, size_t size)

  r = realloc(ptr, size);
  if (!r && size)
-    LOG_FATAL(LOGF_Memory, "Could not allocate memory");
+    LOG_FATAL("Could not allocate memory");

  return r;
 }

+static size_t
+get_array_size(size_t nmemb, size_t size)
+{
+  size_t array_size;
+
+  array_size = nmemb * size;
+
+  /* Check for overflow */
+  if (nmemb > 0 && array_size / nmemb != size)
+    LOG_FATAL("Could not allocate memory");
+
+  return array_size;
+}
+
+void *
+Malloc2(size_t nmemb, size_t size)
+{
+  return Malloc(get_array_size(nmemb, size));
+}
+
+void *
+Realloc2(void *ptr, size_t nmemb, size_t size)
+{
+  return Realloc(ptr, get_array_size(nmemb, size));
+}
+
 char *
 Strdup(const char *s)
 {
@@ -61,7 +87,7 @@ Strdup(const char *s)

  r = strdup(s);
  if (!r)
-    LOG_FATAL(LOGF_Memory, "Could not allocate memory");
+    LOG_FATAL("Could not allocate memory");

  return r;
 }
--- a/memory.h
+++ b/memory.h
@@ -27,15 +27,19 @@
 #ifndef GOT_MEMORY_H
 #define GOT_MEMORY_H

+#include "sysincl.h"
+
 /* Wrappers checking for errors */
 extern void *Malloc(size_t size);
 extern void *Realloc(void *ptr, size_t size);
+extern void *Malloc2(size_t nmemb, size_t size);
+extern void *Realloc2(void *ptr, size_t nmemb, size_t size);
 extern char *Strdup(const char *s);

 /* Convenient macros */
 #define MallocNew(T) ((T *) Malloc(sizeof(T)))
-#define MallocArray(T, n) ((T *) Malloc((n) * sizeof(T)))
-#define ReallocArray(T,n,x) ((T *) Realloc((void *)(x), (n)*sizeof(T)))
+#define MallocArray(T, n) ((T *) Malloc2(n, sizeof(T)))
+#define ReallocArray(T, n, x) ((T *) Realloc2((void *)(x), n, sizeof(T)))
 #define Free(x) free(x)

 #endif /* GOT_MEMORY_H */
--- a/nameserv.c
+++ b/nameserv.c
@@ -30,7 +30,11 @@

 #include "sysincl.h"

+#include <netdb.h>
+#include <resolv.h>
+
 #include "nameserv.h"
+#include "socket.h"
 #include "util.h"

 /* ================================================== */
@@ -53,8 +57,20 @@ DNS_Name2IPAddress(const char *name, IPAddr *ip_addrs, int max_addrs)
  max_addrs = MIN(max_addrs, DNS_MAX_ADDRESSES);

  memset(&hints, 0, sizeof (hints));
-  hints.ai_family = AF_UNSPEC;
-  hints.ai_socktype = SOCK_STREAM;
+
+  switch (address_family) {
+    case IPADDR_INET4:
+      hints.ai_family = AF_INET;
+      break;
+#ifdef FEAT_IPV6
+    case IPADDR_INET6:
+      hints.ai_family = AF_INET6;
+      break;
+#endif
+    default:
+      hints.ai_family = AF_UNSPEC;
+  }
+  hints.ai_socktype = SOCK_DGRAM;

  result = getaddrinfo(name, NULL, &hints, &res);

@@ -141,10 +157,14 @@ DNS_IPAddress2Name(IPAddr *ip_addr, char *name, int len)

 #ifdef FEAT_IPV6
  struct sockaddr_in6 in6;
+  IPSockAddr ip_saddr;
  socklen_t slen;
  char hbuf[NI_MAXHOST];

-  slen = UTI_IPAndPortToSockaddr(ip_addr, 0, (struct sockaddr *)&in6);
+  ip_saddr.ip_addr = *ip_addr;
+  ip_saddr.port = 0;
+
+  slen = SCK_IPSockAddrToSockaddr(&ip_saddr, (struct sockaddr *)&in6, sizeof (in6));
  if (!getnameinfo((struct sockaddr *)&in6, slen, hbuf, sizeof (hbuf), NULL, 0, 0))
    result = hbuf;
 #else
--- a/nameserv_async.c
+++ b/nameserv_async.c
@@ -51,7 +51,7 @@ struct DNS_Async_Instance {
  int pipe[2];
 };

-static int resolving_threads = 0;
+static pthread_mutex_t privops_lock = PTHREAD_MUTEX_INITIALIZER;

 /* ================================================== */

@@ -60,7 +60,9 @@ start_resolving(void *anything)
 {
  struct DNS_Async_Instance *inst = (struct DNS_Async_Instance *)anything;

+  pthread_mutex_lock(&privops_lock);
  inst->status = PRV_Name2IPAddress(inst->name, inst->addresses, DNS_MAX_ADDRESSES);
+  pthread_mutex_unlock(&privops_lock);

  /* Notify the main thread that the result is ready */
  if (write(inst->pipe[1], "", 1) < 0)
@@ -72,18 +74,16 @@ start_resolving(void *anything)
 /* ================================================== */

 static void
-end_resolving(void *anything)
+end_resolving(int fd, int event, void *anything)
 {
  struct DNS_Async_Instance *inst = (struct DNS_Async_Instance *)anything;
  int i;

  if (pthread_join(inst->thread, NULL)) {
-    LOG_FATAL(LOGF_Nameserv, "pthread_join() failed");
+    LOG_FATAL("pthread_join() failed");
  }

-  resolving_threads--;
-
-  SCH_RemoveInputFileHandler(inst->pipe[0]);
+  SCH_RemoveFileHandler(inst->pipe[0]);
  close(inst->pipe[0]);
  close(inst->pipe[1]);

@@ -110,17 +110,17 @@ DNS_Name2IPAddressAsync(const char *name, DNS_NameResolveHandler handler, void *
  inst->status = DNS_Failure;

  if (pipe(inst->pipe)) {
-    LOG_FATAL(LOGF_Nameserv, "pipe() failed");
+    LOG_FATAL("pipe() failed");
  }

-  resolving_threads++;
-  assert(resolving_threads <= 1);
+  UTI_FdSetCloexec(inst->pipe[0]);
+  UTI_FdSetCloexec(inst->pipe[1]);

  if (pthread_create(&inst->thread, NULL, start_resolving, inst)) {
-    LOG_FATAL(LOGF_Nameserv, "pthread_create() failed");
+    LOG_FATAL("pthread_create() failed");
  }

-  SCH_AddInputFileHandler(inst->pipe[0], end_resolving, inst);
+  SCH_AddFileHandler(inst->pipe[0], SCH_FILE_INPUT, end_resolving, inst);
 }

 /* ================================================== */
--- a/ntp.h
+++ b/ntp.h
@@ -38,24 +38,34 @@ typedef struct {

 typedef uint32_t NTP_int32;

+/* The UDP port number used by NTP */
+#define NTP_PORT 123
+
 /* The NTP protocol version that we support */
 #define NTP_VERSION 4

 /* Maximum stratum number (infinity) */
 #define NTP_MAX_STRATUM 16

-/* The minimum valid length of an extension field */
-#define NTP_MIN_EXTENSION_LENGTH 16
-
-/* The maximum assumed length of all extension fields in received
-   packets (RFC 5905 doesn't specify a limit on length or number of
-   extension fields in one packet) */
-#define NTP_MAX_EXTENSIONS_LENGTH 1024
+/* Invalid stratum number */
+#define NTP_INVALID_STRATUM 0

 /* The minimum and maximum supported length of MAC */
 #define NTP_MIN_MAC_LENGTH (4 + 16)
 #define NTP_MAX_MAC_LENGTH (4 + MAX_HASH_LENGTH)

+/* The minimum valid length of an extension field */
+#define NTP_MIN_EF_LENGTH 16
+
+/* The maximum assumed length of all extension fields in an NTP packet,
+   including a MAC (RFC 5905 doesn't specify a limit on length or number of
+   extension fields in one packet) */
+#define NTP_MAX_EXTENSIONS_LENGTH (1024 + NTP_MAX_MAC_LENGTH)
+
+/* The maximum length of MAC in NTPv4 packets which allows deterministic
+   parsing of extension fields (RFC 7822) */
+#define NTP_MAX_V4_MAC_LENGTH (4 + 20)
+
 /* Type definition for leap bits */
 typedef enum {
  LEAP_Normal = 0,
@@ -86,21 +96,10 @@ typedef struct {
  NTP_int64 receive_ts;
  NTP_int64 transmit_ts;

-  /* Optional extension fields, we don't send packets with them yet */
-  /* uint8_t extensions[] */
-
-  /* Optional message authentication code (MAC) */
-  NTP_int32 auth_keyid;
-  uint8_t auth_data[NTP_MAX_MAC_LENGTH - 4];
+  uint8_t extensions[NTP_MAX_EXTENSIONS_LENGTH];
 } NTP_Packet;

-#define NTP_NORMAL_PACKET_LENGTH (int)offsetof(NTP_Packet, auth_keyid)
-
-/* The buffer used to hold a datagram read from the network */
-typedef struct {
-  NTP_Packet ntp_pkt;
-  uint8_t extensions[NTP_MAX_EXTENSIONS_LENGTH];
-} NTP_Receive_Buffer;
+#define NTP_HEADER_LENGTH (int)offsetof(NTP_Packet, extensions)

 /* Macros to work with the lvm field */
 #define NTP_LVM_TO_LEAP(lvm) (((lvm) >> 6) & 0x3)
@@ -114,4 +113,45 @@ typedef struct {
 #define NTP_REFID_LOCAL 0x7F7F0101UL /* 127.127.1.1 */
 #define NTP_REFID_SMOOTH 0x7F7F01FFUL /* 127.127.1.255 */

+/* Enumeration for authentication modes of NTP packets */
+typedef enum {
+  NTP_AUTH_NONE = 0,            /* No authentication */
+  NTP_AUTH_SYMMETRIC,           /* MAC using symmetric key (RFC 1305, RFC 5905) */
+  NTP_AUTH_MSSNTP,              /* MS-SNTP authenticator field */
+  NTP_AUTH_MSSNTP_EXT,          /* MS-SNTP extended authenticator field */
+  NTP_AUTH_NTS,                 /* Network Time Security (RFC ????) */
+} NTP_AuthMode;
+
+/* Structure describing an NTP packet */
+typedef struct {
+  int length;
+  int version;
+  NTP_Mode mode;
+
+  int ext_fields;
+
+  struct {
+    NTP_AuthMode mode;
+    struct {
+      int start;
+      int length;
+      uint32_t key_id;
+    } mac;
+  } auth;
+} NTP_PacketInfo;
+
+/* Structure used to save NTP measurements.  time is the local time at which
+   the sample is to be considered to have been made and offset is the offset at
+   the time (positive indicates that the local clock is slow relative to the
+   source).  root_delay/root_dispersion include peer_delay/peer_dispersion. */
+typedef struct {
+  struct timespec time;
+  double offset;
+  double peer_delay;
+  double peer_dispersion;
+  double root_delay;
+  double root_dispersion;
+  int stratum;
+} NTP_Sample;
+
 #endif /* GOT_NTP_H */
--- a/ntp_auth.c
+++ b/ntp_auth.c
@@ -0,0 +1,486 @@
+/*
+  chronyd/chronyc - Programs for keeping computer clocks accurate.
+
+ **********************************************************************
+ * Copyright (C) Miroslav Lichvar  2019
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ * 
+ **********************************************************************
+
+  =======================================================================
+
+  NTP authentication
+  */
+
+#include "config.h"
+
+#include "sysincl.h"
+
+#include "keys.h"
+#include "logging.h"
+#include "memory.h"
+#include "ntp_auth.h"
+#include "ntp_ext.h"
+#include "ntp_signd.h"
+#include "nts_ntp.h"
+#include "nts_ntp_client.h"
+#include "nts_ntp_server.h"
+#include "srcparams.h"
+#include "util.h"
+
+/* Structure to hold authentication configuration and state */
+
+struct NAU_Instance_Record {
+  NTP_AuthMode mode;            /* Authentication mode of NTP packets */
+  uint32_t key_id;              /* Identifier of a symmetric key */
+  NNC_Instance nts;             /* Client NTS state */
+};
+
+/* ================================================== */
+
+static int
+generate_symmetric_auth(uint32_t key_id, NTP_Packet *packet, NTP_PacketInfo *info)
+{
+  int auth_len, max_auth_len;
+
+  /* Truncate long MACs in NTPv4 packets to allow deterministic parsing
+     of extension fields (RFC 7822) */
+  max_auth_len = (info->version == 4 ? NTP_MAX_V4_MAC_LENGTH : NTP_MAX_MAC_LENGTH) - 4;
+  max_auth_len = MIN(max_auth_len, sizeof (NTP_Packet) - info->length - 4);
+
+  auth_len = KEY_GenerateAuth(key_id, (unsigned char *)packet, info->length,
+                              (unsigned char *)packet + info->length + 4, max_auth_len);
+  if (!auth_len) {
+    DEBUG_LOG("Could not generate auth data with key %"PRIu32, key_id);
+    return 0;
+  }
+
+  *(uint32_t *)((unsigned char *)packet + info->length) = htonl(key_id);
+  info->length += 4 + auth_len;
+
+  return 1;
+}
+
+/* ================================================== */
+
+static int
+check_symmetric_auth(NTP_Packet *packet, NTP_PacketInfo *info)
+{
+  int trunc_len;
+
+  if (info->auth.mac.length < NTP_MIN_MAC_LENGTH)
+    return 0;
+
+  trunc_len = info->version == 4 && info->auth.mac.length <= NTP_MAX_V4_MAC_LENGTH ?
+              NTP_MAX_V4_MAC_LENGTH : NTP_MAX_MAC_LENGTH;
+
+  if (!KEY_CheckAuth(info->auth.mac.key_id, (void *)packet, info->auth.mac.start,
+                     (unsigned char *)packet + info->auth.mac.start + 4,
+                     info->auth.mac.length - 4, trunc_len - 4))
+    return 0;
+
+  return 1;
+}
+
+/* ================================================== */
+
+static void
+adjust_timestamp(NTP_AuthMode mode, uint32_t key_id, struct timespec *ts)
+{
+  switch (mode) {
+    case NTP_AUTH_SYMMETRIC:
+      ts->tv_nsec += KEY_GetAuthDelay(key_id);
+      UTI_NormaliseTimespec(ts);
+      break;
+    case NTP_AUTH_MSSNTP:
+      ts->tv_nsec += NSD_GetAuthDelay(key_id);
+      UTI_NormaliseTimespec(ts);
+    default:
+      break;
+  }
+}
+
+/* ================================================== */
+
+static int
+is_zero_data(unsigned char *data, int length)
+{
+  int i;
+
+  for (i = 0; i < length; i++)
+    if (data[i])
+      return 0;
+  return 1;
+}
+
+/* ================================================== */
+
+static NAU_Instance
+create_instance(NTP_AuthMode mode)
+{
+  NAU_Instance instance;
+
+  instance = MallocNew(struct NAU_Instance_Record);
+  instance->mode = mode;
+  instance->key_id = INACTIVE_AUTHKEY;
+  instance->nts = NULL;
+
+  assert(sizeof (instance->key_id) == 4);
+
+  return instance;
+}
+
+/* ================================================== */
+
+NAU_Instance
+NAU_CreateNoneInstance(void)
+{
+  return create_instance(NTP_AUTH_NONE);
+}
+
+/* ================================================== */
+
+NAU_Instance
+NAU_CreateSymmetricInstance(uint32_t key_id)
+{
+  NAU_Instance instance = create_instance(NTP_AUTH_SYMMETRIC);
+
+  instance->key_id = key_id;
+
+  if (!KEY_KeyKnown(key_id))
+    LOG(LOGS_WARN, "Key %"PRIu32" is %s", key_id, "missing");
+  else if (!KEY_CheckKeyLength(key_id))
+    LOG(LOGS_WARN, "Key %"PRIu32" is %s", key_id, "too short");
+
+  return instance;
+}
+
+/* ================================================== */
+
+NAU_Instance
+NAU_CreateNtsInstance(IPSockAddr *nts_address, const char *name, const IPSockAddr *ntp_address)
+{
+  NAU_Instance instance = create_instance(NTP_AUTH_NTS);
+
+  instance->nts = NNC_CreateInstance(nts_address, name, ntp_address);
+
+  return instance;
+}
+
+/* ================================================== */
+
+void
+NAU_DestroyInstance(NAU_Instance instance)
+{
+  if (instance->nts)
+    NNC_DestroyInstance(instance->nts);
+  Free(instance);
+}
+
+/* ================================================== */
+
+int
+NAU_IsAuthEnabled(NAU_Instance instance)
+{
+  return instance->mode != NTP_AUTH_NONE;
+}
+
+/* ================================================== */
+
+int
+NAU_GetSuggestedNtpVersion(NAU_Instance instance)
+{
+  /* If the MAC in NTPv4 packets would be truncated, prefer NTPv3 for
+     compatibility with older chronyd servers */
+  if (instance->mode == NTP_AUTH_SYMMETRIC &&
+      KEY_GetAuthLength(instance->key_id) + sizeof (instance->key_id) > NTP_MAX_V4_MAC_LENGTH)
+    return 3;
+
+  return NTP_VERSION;
+}
+
+/* ================================================== */
+
+int
+NAU_PrepareRequestAuth(NAU_Instance instance)
+{
+  switch (instance->mode) {
+    case NTP_AUTH_NTS:
+      if (!NNC_PrepareForAuth(instance->nts))
+        return 0;
+      break;
+    default:
+      break;
+  }
+
+  return 1;
+}
+
+/* ================================================== */
+
+void
+NAU_AdjustRequestTimestamp(NAU_Instance instance, struct timespec *ts)
+{
+  adjust_timestamp(instance->mode, instance->key_id, ts);
+}
+
+/* ================================================== */
+
+int
+NAU_GenerateRequestAuth(NAU_Instance instance, NTP_Packet *request, NTP_PacketInfo *info)
+{
+  switch (instance->mode) {
+    case NTP_AUTH_NONE:
+      break;
+    case NTP_AUTH_SYMMETRIC:
+      if (!generate_symmetric_auth(instance->key_id, request, info))
+        return 0;
+      break;
+    case NTP_AUTH_NTS:
+      if (!NNC_GenerateRequestAuth(instance->nts, request, info))
+        return 0;
+      break;
+    default:
+      assert(0);
+  }
+
+  return 1;
+}
+
+/* ================================================== */
+
+int
+NAU_ParsePacket(NTP_Packet *packet, NTP_PacketInfo *info)
+{
+  int parsed, remainder, ef_length, ef_type;
+  unsigned char *data;
+
+  data = (void *)packet;
+  parsed = NTP_HEADER_LENGTH;
+  remainder = info->length - parsed;
+
+  info->ext_fields = 0;
+
+  /* Check if this is a plain NTP packet with no extension fields or MAC */
+  if (remainder <= 0)
+    return 1;
+
+  /* In NTPv3 and older packets don't have extension fields.  Anything after
+     the header is assumed to be a MAC. */
+  if (info->version <= 3) {
+    info->auth.mode = NTP_AUTH_SYMMETRIC;
+    info->auth.mac.start = parsed;
+    info->auth.mac.length = remainder;
+    info->auth.mac.key_id = ntohl(*(uint32_t *)(data + parsed));
+
+    /* Check if it is an MS-SNTP authenticator field or extended authenticator
+       field with zeroes as digest */
+    if (info->version == 3 && info->auth.mac.key_id) {
+      if (remainder == 20 && is_zero_data(data + parsed + 4, remainder - 4))
+        info->auth.mode = NTP_AUTH_MSSNTP;
+      else if (remainder == 72 && is_zero_data(data + parsed + 8, remainder - 8))
+        info->auth.mode = NTP_AUTH_MSSNTP_EXT;
+    }
+
+    return 1;
+  }
+
+  /* Check for a crypto NAK */
+  if (remainder == 4 && ntohl(*(uint32_t *)(data + parsed)) == 0) {
+    info->auth.mode = NTP_AUTH_SYMMETRIC;
+    info->auth.mac.start = parsed;
+    info->auth.mac.length = remainder;
+    info->auth.mac.key_id = 0;
+    return 1;
+  }
+
+  /* Parse the rest of the NTPv4 packet */
+
+  while (remainder > 0) {
+    /* Check if the remaining data is a MAC */
+    if (remainder >= NTP_MIN_MAC_LENGTH && remainder <= NTP_MAX_V4_MAC_LENGTH)
+      break;
+
+    /* The NTPv4-specific limit for MAC length enables deterministic parsing of
+       packets with extension fields (RFC 7822), but we support longer MACs in
+       packets with no extension fields for compatibility with older chrony
+       clients.  Check if the longer MAC would authenticate the packet before
+       trying to parse the data as an extension field. */
+    if (parsed == NTP_HEADER_LENGTH &&
+        remainder > NTP_MAX_V4_MAC_LENGTH && remainder <= NTP_MAX_MAC_LENGTH &&
+        KEY_CheckAuth(ntohl(*(uint32_t *)(data + parsed)), data, parsed,
+                      (void *)(data + parsed + 4), remainder - 4, NTP_MAX_MAC_LENGTH - 4))
+      break;
+
+    /* Check if this is a valid NTPv4 extension field and skip it */
+    if (!NEF_ParseField(packet, info->length, parsed, &ef_length, &ef_type, NULL, NULL)) {
+      /* Invalid MAC or format error */
+      DEBUG_LOG("Invalid format or MAC");
+      return 0;
+    }
+
+    assert(ef_length > 0);
+
+    switch (ef_type) {
+      case NTP_EF_NTS_UNIQUE_IDENTIFIER:
+      case NTP_EF_NTS_COOKIE:
+      case NTP_EF_NTS_COOKIE_PLACEHOLDER:
+      case NTP_EF_NTS_AUTH_AND_EEF:
+        info->auth.mode = NTP_AUTH_NTS;
+        break;
+      default:
+        DEBUG_LOG("Unknown extension field type=%x", (unsigned int)ef_type);
+    }
+
+    info->ext_fields++;
+    parsed += ef_length;
+    remainder = info->length - parsed;
+  }
+
+  if (remainder == 0) {
+    /* No MAC */
+    return 1;
+  } else if (remainder >= NTP_MIN_MAC_LENGTH) {
+    /* This is not 100% reliable as a MAC could fail to authenticate and could
+       pass as an extension field, leaving reminder smaller than the minimum MAC
+       length */
+    info->auth.mode = NTP_AUTH_SYMMETRIC;
+    info->auth.mac.start = parsed;
+    info->auth.mac.length = remainder;
+    info->auth.mac.key_id = ntohl(*(uint32_t *)(data + parsed));
+    return 1;
+  }
+
+  DEBUG_LOG("Invalid format");
+  return 0;
+}
+
+/* ================================================== */
+
+int
+NAU_CheckRequestAuth(NTP_Packet *request, NTP_PacketInfo *info, uint32_t *kod)
+{
+  *kod = 0;
+
+  switch (info->auth.mode) {
+    case NTP_AUTH_NONE:
+      break;
+    case NTP_AUTH_SYMMETRIC:
+      if (!check_symmetric_auth(request, info))
+        return 0;
+      break;
+    case NTP_AUTH_MSSNTP:
+      /* MS-SNTP requests are not authenticated */
+      break;
+    case NTP_AUTH_NTS:
+      if (!NNS_CheckRequestAuth(request, info, kod))
+        return 0;
+      break;
+    default:
+      return 0;
+  }
+
+  return 1;
+}
+
+/* ================================================== */
+
+void
+NAU_AdjustResponseTimestamp(NTP_Packet *request, NTP_PacketInfo *info, struct timespec *ts)
+{
+  adjust_timestamp(info->auth.mode, info->auth.mac.key_id, ts);
+}
+
+/* ================================================== */
+
+int
+NAU_GenerateResponseAuth(NTP_Packet *request, NTP_PacketInfo *request_info,
+                         NTP_Packet *response, NTP_PacketInfo *response_info,
+                         NTP_Remote_Address *remote_addr, NTP_Local_Address *local_addr,
+                         uint32_t kod)
+{
+  switch (request_info->auth.mode) {
+    case NTP_AUTH_NONE:
+      break;
+    case NTP_AUTH_SYMMETRIC:
+      if (!generate_symmetric_auth(request_info->auth.mac.key_id, response, response_info))
+        return 0;
+      break;
+    case NTP_AUTH_MSSNTP:
+      /* Sign the packet asynchronously by ntp_signd */
+      if (!NSD_SignAndSendPacket(request_info->auth.mac.key_id, response, response_info,
+                                 remote_addr, local_addr))
+        return 0;
+      /* Don't send the original packet */
+      return 0;
+    case NTP_AUTH_NTS:
+      if (!NNS_GenerateResponseAuth(request, request_info, response, response_info, kod))
+        return 0;
+      break;
+    default:
+      DEBUG_LOG("Could not authenticate response auth_mode=%d", (int)request_info->auth.mode);
+      return 0;
+  }
+
+  return 1;
+}
+
+/* ================================================== */
+
+int
+NAU_CheckResponseAuth(NAU_Instance instance, NTP_Packet *response, NTP_PacketInfo *info)
+{
+  /* The authentication must match the expected mode */
+  if (info->auth.mode != instance->mode)
+    return 0;
+
+  switch (info->auth.mode) {
+    case NTP_AUTH_NONE:
+      break;
+    case NTP_AUTH_SYMMETRIC:
+      /* Check if it is authenticated with the specified key */
+      if (info->auth.mac.key_id != instance->key_id)
+        return 0;
+      /* and that the MAC is valid */
+      if (!check_symmetric_auth(response, info))
+        return 0;
+      break;
+    case NTP_AUTH_NTS:
+      if (!NNC_CheckResponseAuth(instance->nts, response, info))
+        return 0;
+      break;
+    default:
+      return 0;
+  }
+
+  return 1;
+}
+
+/* ================================================== */
+
+void
+NAU_ChangeAddress(NAU_Instance instance, IPAddr *address)
+{
+  switch (instance->mode) {
+    case NTP_AUTH_NONE:
+    case NTP_AUTH_SYMMETRIC:
+      break;
+    case NTP_AUTH_NTS:
+      NNC_ChangeAddress(instance->nts, address);
+      break;
+    default:
+      assert(0);
+  }
+}
--- a/ntp_auth.h
+++ b/ntp_auth.h
@@ -0,0 +1,89 @@
+/*
+  chronyd/chronyc - Programs for keeping computer clocks accurate.
+
+ **********************************************************************
+ * Copyright (C) Miroslav Lichvar  2019
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ * 
+ **********************************************************************
+
+  =======================================================================
+
+  Header file for NTP authentication
+  */
+
+#ifndef GOT_NTP_AUTH_H
+#define GOT_NTP_AUTH_H
+
+#include "addressing.h"
+#include "ntp.h"
+
+typedef struct NAU_Instance_Record *NAU_Instance;
+
+/* Create an authenticator instance in a specific mode */
+extern NAU_Instance NAU_CreateNoneInstance(void);
+extern NAU_Instance NAU_CreateSymmetricInstance(uint32_t key_id);
+extern NAU_Instance NAU_CreateNtsInstance(IPSockAddr *nts_address, const char *name,
+                                          const IPSockAddr *ntp_address);
+
+/* Destroy an instance */
+extern void NAU_DestroyInstance(NAU_Instance instance);
+
+/* Check if an instance is not in the None mode */
+extern int NAU_IsAuthEnabled(NAU_Instance instance);
+
+/* Get NTP version recommended for better compatibility */
+extern int NAU_GetSuggestedNtpVersion(NAU_Instance instance);
+
+/* Perform operations necessary for NAU_GenerateRequestAuth() */
+extern int NAU_PrepareRequestAuth(NAU_Instance instance);
+
+/* Adjust a transmit timestamp for an estimated minimum time it takes to call
+   NAU_GenerateRequestAuth() */
+extern void NAU_AdjustRequestTimestamp(NAU_Instance instance, struct timespec *ts);
+
+/* Extend a request with data required by the authentication mode */
+extern int NAU_GenerateRequestAuth(NAU_Instance instance, NTP_Packet *request,
+                                   NTP_PacketInfo *info);
+
+/* Parse a request or response to detect the authentication mode */
+extern int NAU_ParsePacket(NTP_Packet *packet, NTP_PacketInfo *info);
+
+/* Verify that a request is authentic.  If it is not authentic and a non-zero
+   kod code is returned, a KoD response should be sent back. */
+extern int NAU_CheckRequestAuth(NTP_Packet *request, NTP_PacketInfo *info, uint32_t *kod);
+
+/* Adjust a transmit timestamp for an estimated minimum time it takes to call
+   NAU_GenerateResponseAuth() */
+extern void NAU_AdjustResponseTimestamp(NTP_Packet *request, NTP_PacketInfo *info,
+                                        struct timespec *ts);
+
+/* Extend a response with data required by the authentication mode.  This
+   function can be called only if the previous call of NAU_CheckRequestAuth()
+   was on the same request. */
+extern int NAU_GenerateResponseAuth(NTP_Packet *request, NTP_PacketInfo *request_info,
+                                    NTP_Packet *response, NTP_PacketInfo *response_info,
+                                    NTP_Remote_Address *remote_addr,
+                                    NTP_Local_Address *local_addr,
+                                    uint32_t kod);
+
+/* Verify that a response is authentic */
+extern int NAU_CheckResponseAuth(NAU_Instance instance, NTP_Packet *response,
+                                 NTP_PacketInfo *info);
+
+/* Change an authentication-specific address (e.g. after replacing a source) */
+extern void NAU_ChangeAddress(NAU_Instance instance, IPAddr *address);
+
+#endif
--- a/ntp_core.c
+++ b/ntp_core.c
--- a/ntp_core.h
+++ b/ntp_core.h
@@ -38,6 +38,18 @@ typedef enum {
  NTP_SERVER, NTP_PEER
 } NTP_Source_Type;

+typedef enum {
+  NTP_TS_DAEMON = 0,
+  NTP_TS_KERNEL,
+  NTP_TS_HARDWARE
+} NTP_Timestamp_Source;
+
+typedef struct {
+  struct timespec ts;
+  double err;
+  NTP_Timestamp_Source source;
+} NTP_Local_Timestamp;
+
 /* This is a private data type used for storing the instance record for
   each source that we are chiming with */
 typedef struct NCR_Instance_Record *NCR_Instance;
@@ -47,7 +59,8 @@ extern void NCR_Initialise(void);
 extern void NCR_Finalise(void);

 /* Get a new instance for a server or peer */
-extern NCR_Instance NCR_GetInstance(NTP_Remote_Address *remote_addr, NTP_Source_Type type, SourceParameters *params);
+extern NCR_Instance NCR_CreateInstance(NTP_Remote_Address *remote_addr, NTP_Source_Type type,
+                                       SourceParameters *params, const char *name);

 /* Destroy an instance */
 extern void NCR_DestroyInstance(NCR_Instance instance);
@@ -58,26 +71,39 @@ extern void NCR_StartInstance(NCR_Instance instance);
 /* Reset an instance */
 extern void NCR_ResetInstance(NCR_Instance inst);

+/* Reset polling interval of an instance */
+extern void NCR_ResetPoll(NCR_Instance instance);
+
 /* Change the remote address of an instance */
-extern void NCR_ChangeRemoteAddress(NCR_Instance inst, NTP_Remote_Address *remote_addr);
+extern void NCR_ChangeRemoteAddress(NCR_Instance inst, NTP_Remote_Address *remote_addr,
+                                    int ntp_only);

 /* This routine is called when a new packet arrives off the network,
   and it relates to a source we have an ongoing protocol exchange with */
-extern int NCR_ProcessKnown(NTP_Packet *message, struct timeval *now, double now_err, NCR_Instance data, NTP_Local_Address *local_addr, int length);
+extern int NCR_ProcessRxKnown(NCR_Instance inst, NTP_Local_Address *local_addr,
+                              NTP_Local_Timestamp *rx_ts, NTP_Packet *message, int length);

 /* This routine is called when a new packet arrives off the network,
   and we do not recognize its source */
-extern void NCR_ProcessUnknown(NTP_Packet *message, struct timeval *now, double now_err, NTP_Remote_Address *remote_addr, NTP_Local_Address *local_addr, int length);
+extern void NCR_ProcessRxUnknown(NTP_Remote_Address *remote_addr, NTP_Local_Address *local_addr,
+                                 NTP_Local_Timestamp *rx_ts, NTP_Packet *message, int length);
+
+/* This routine is called when a packet is sent to a source we have
+   an ongoing protocol exchange with */
+extern void NCR_ProcessTxKnown(NCR_Instance inst, NTP_Local_Address *local_addr,
+                               NTP_Local_Timestamp *tx_ts, NTP_Packet *message, int length);
+
+/* This routine is called when a packet is sent to a destination we
+   do not recognize */
+extern void NCR_ProcessTxUnknown(NTP_Remote_Address *remote_addr, NTP_Local_Address *local_addr,
+                                 NTP_Local_Timestamp *tx_ts, NTP_Packet *message, int length);

 /* Slew receive and transmit times in instance records */
-extern void NCR_SlewTimes(NCR_Instance inst, struct timeval *when, double dfreq, double doffset);
+extern void NCR_SlewTimes(NCR_Instance inst, struct timespec *when, double dfreq, double doffset);

-/* Take a particular source online (i.e. start sampling it) */
-extern void NCR_TakeSourceOnline(NCR_Instance inst);
-
-/* Take a particular source offline (i.e. stop sampling it, without
-   marking it unreachable in the source selection stuff) */
-extern void NCR_TakeSourceOffline(NCR_Instance inst);
+/* Take a particular source online (i.e. start sampling it) or offline
+   (i.e. stop sampling it) */
+extern void NCR_SetConnectivity(NCR_Instance inst, SRC_Connectivity connectivity);

 extern void NCR_ModifyMinpoll(NCR_Instance inst, int new_minpoll);

@@ -95,7 +121,8 @@ extern void NCR_ModifyPolltarget(NCR_Instance inst, int new_poll_target);

 extern void NCR_InitiateSampleBurst(NCR_Instance inst, int n_good_samples, int n_total_samples);

-extern void NCR_ReportSource(NCR_Instance inst, RPT_SourceReport *report, struct timeval *now);
+extern void NCR_ReportSource(NCR_Instance inst, RPT_SourceReport *report, struct timespec *now);
+extern void NCR_GetNTPReport(NCR_Instance inst, RPT_NTPReport *report);

 extern int NCR_AddAccessRestriction(IPAddr *ip_addr, int subnet_bits, int allow, int all);
 extern int NCR_CheckAccessRestriction(IPAddr *ip_addr);
--- a/ntp_ext.c
+++ b/ntp_ext.c
@@ -0,0 +1,192 @@
+/*
+  chronyd/chronyc - Programs for keeping computer clocks accurate.
+
+ **********************************************************************
+ * Copyright (C) Miroslav Lichvar  2019
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ * 
+ **********************************************************************
+
+  =======================================================================
+
+  Functions for adding and parsing NTPv4 extension fields
+  */
+
+#include "config.h"
+
+#include "sysincl.h"
+
+#include "ntp_ext.h"
+
+struct ExtFieldHeader {
+  uint16_t type;
+  uint16_t length;
+};
+
+/* ================================================== */
+
+static int
+format_field(unsigned char *buffer, int buffer_length, int start,
+             int type, int body_length, int *length, void **body)
+{
+  struct ExtFieldHeader *header;
+
+  if (buffer_length < 0 || start < 0 || buffer_length <= start ||
+      buffer_length - start < sizeof (*header) || start % 4 != 0)
+    return 0;
+
+  header = (struct ExtFieldHeader *)(buffer + start);
+
+  if (body_length < 0 || sizeof (*header) + body_length > 0xffff ||
+      start + sizeof (*header) + body_length > buffer_length || body_length % 4 != 0)
+    return 0;
+
+  header->type = htons(type);
+  header->length = htons(sizeof (*header) + body_length);
+  *length = sizeof (*header) + body_length;
+  *body = header + 1;
+
+  return 1;
+}
+
+/* ================================================== */
+
+int
+NEF_SetField(unsigned char *buffer, int buffer_length, int start,
+             int type, void *body, int body_length, int *length)
+{
+  void *ef_body;
+
+  if (!format_field(buffer, buffer_length, start, type, body_length, length, &ef_body))
+    return 0;
+
+  memcpy(ef_body, body, body_length);
+
+  return 1;
+}
+
+/* ================================================== */
+
+int
+NEF_AddBlankField(NTP_Packet *packet, NTP_PacketInfo *info, int type, int body_length, void **body)
+{
+  int ef_length, length = info->length;
+
+  if (length < NTP_HEADER_LENGTH || length >= sizeof (*packet) || length % 4 != 0)
+    return 0;
+
+  /* Only NTPv4 packets can have extension fields */
+  if (info->version != 4)
+    return 0;
+
+  if (!format_field((unsigned char *)packet, sizeof (*packet), length,
+                    type, body_length, &ef_length, body))
+    return 0;
+
+  if (ef_length < NTP_MIN_EF_LENGTH)
+    return 0;
+
+  info->length += ef_length;
+  info->ext_fields++;
+
+  return 1;
+}
+
+/* ================================================== */
+
+int
+NEF_AddField(NTP_Packet *packet, NTP_PacketInfo *info,
+             int type, void *body, int body_length)
+{
+  void *ef_body;
+
+  if (!NEF_AddBlankField(packet, info, type, body_length, &ef_body))
+    return 0;
+
+  memcpy(ef_body, body, body_length);
+
+  return 1;
+}
+
+/* ================================================== */
+
+int
+NEF_ParseSingleField(unsigned char *buffer, int buffer_length, int start,
+                     int *length, int *type, void **body, int *body_length)
+{
+  struct ExtFieldHeader *header;
+  int ef_length;
+
+  if (buffer_length < 0 || start < 0 || buffer_length <= start ||
+      buffer_length - start < sizeof (*header))
+    return 0;
+
+  header = (struct ExtFieldHeader *)(buffer + start);
+
+  assert(sizeof (*header) == 4);
+
+  ef_length = ntohs(header->length);
+
+  if (ef_length < (int)(sizeof (*header)) || start + ef_length > buffer_length ||
+      ef_length % 4 != 0)
+    return 0;
+
+  if (length)
+    *length = ef_length;
+  if (type)
+    *type = ntohs(header->type);
+  if (body)
+    *body = header + 1;
+  if (body_length)
+    *body_length = ef_length - sizeof (*header);
+
+  return 1;
+}
+
+/* ================================================== */
+
+int
+NEF_ParseField(NTP_Packet *packet, int packet_length, int start,
+               int *length, int *type, void **body, int *body_length)
+{
+  int ef_length;
+
+  if (packet_length <= NTP_HEADER_LENGTH || packet_length > sizeof (*packet) ||
+      packet_length <= start || packet_length % 4 != 0 ||
+      start < NTP_HEADER_LENGTH || start % 4 != 0)
+    return 0;
+
+  /* Only NTPv4 packets have extension fields */
+  if (NTP_LVM_TO_VERSION(packet->lvm) != 4)
+    return 0;
+
+  /* Check if the remaining data is a MAC.  RFC 7822 specifies the maximum
+     length of a MAC in NTPv4 packets in order to enable deterministic
+     parsing. */
+  if (packet_length - start <= NTP_MAX_V4_MAC_LENGTH)
+    return 0;
+
+  if (!NEF_ParseSingleField((unsigned char *)packet, packet_length, start,
+                            &ef_length, type, body, body_length))
+    return 0;
+
+  if (ef_length < NTP_MIN_EF_LENGTH)
+    return 0;
+
+  if (length)
+    *length = ef_length;
+
+  return 1;
+}
--- a/ntp_ext.h
+++ b/ntp_ext.h
@@ -0,0 +1,43 @@
+/*
+  chronyd/chronyc - Programs for keeping computer clocks accurate.
+
+ **********************************************************************
+ * Copyright (C) Miroslav Lichvar  2019
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ * 
+ **********************************************************************
+
+  =======================================================================
+
+  Header file for NTP extension fields
+  */
+
+#ifndef GOT_NTP_EXT_H
+#define GOT_NTP_EXT_H
+
+#include "ntp.h"
+
+extern int NEF_SetField(unsigned char *buffer, int buffer_length, int start,
+                        int type, void *body, int body_length, int *length);
+extern int NEF_AddBlankField(NTP_Packet *packet, NTP_PacketInfo *info, int type,
+                             int body_length, void **body);
+extern int NEF_AddField(NTP_Packet *packet, NTP_PacketInfo *info,
+                        int type, void *body, int body_length);
+extern int NEF_ParseSingleField(unsigned char *buffer, int buffer_length, int start,
+                                int *length, int *type, void **body, int *body_length);
+extern int NEF_ParseField(NTP_Packet *packet, int packet_length, int start,
+                          int *length, int *type, void **body, int *body_length);
+
+#endif
--- a/ntp_io.c
+++ b/ntp_io.c
@@ -4,7 +4,7 @@
 **********************************************************************
 * Copyright (C) Richard P. Curnow  1997-2003
 * Copyright (C) Timo Teras  2009
- * Copyright (C) Miroslav Lichvar  2009, 2013-2015
+ * Copyright (C) Miroslav Lichvar  2009, 2013-2016, 2018
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
@@ -34,35 +34,28 @@
 #include "ntp_core.h"
 #include "ntp_sources.h"
 #include "sched.h"
+#include "socket.h"
 #include "local.h"
 #include "logging.h"
 #include "conf.h"
 #include "privops.h"
 #include "util.h"

-#define INVALID_SOCK_FD -1
-
-union sockaddr_in46 {
-  struct sockaddr_in in4;
-#ifdef FEAT_IPV6
-  struct sockaddr_in6 in6;
+#ifdef HAVE_LINUX_TIMESTAMPING
+#include "ntp_io_linux.h"
 #endif
-  struct sockaddr u;
-};
+
+#define INVALID_SOCK_FD -1

 /* The server/peer and client sockets for IPv4 and IPv6 */
 static int server_sock_fd4;
-static int client_sock_fd4;
-#ifdef FEAT_IPV6
 static int server_sock_fd6;
+static int client_sock_fd4;
 static int client_sock_fd6;
-#endif

 /* Reference counters for server sockets to keep them open only when needed */
 static int server_sock_ref4;
-#ifdef FEAT_IPV6
 static int server_sock_ref6;
-#endif

 /* Flag indicating we create a new connected client socket for each
   server instead of sharing client_sock_fd4 and client_sock_fd6 */
@@ -74,163 +67,61 @@ static int separate_client_sockets;
   disabled */
 static int permanent_server_sockets;

+/* Flag indicating the server IPv4 socket is bound to an address */
+static int bound_server_sock_fd4;
+
 /* Flag indicating that we have been initialised */
 static int initialised=0;

 /* ================================================== */

 /* Forward prototypes */
-static void read_from_socket(void *anything);
+static void read_from_socket(int sock_fd, int event, void *anything);

 /* ================================================== */

 static int
-prepare_socket(int family, int port_number, int client_only)
+open_socket(int family, int local_port, int client_only, IPSockAddr *remote_addr)
 {
-  union sockaddr_in46 my_addr;
-  socklen_t my_addr_len;
-  int sock_fd;
-  IPAddr bind_address;
-  int on_off = 1;
-  
-  /* Open Internet domain UDP socket for NTP message transmissions */
+  int sock_fd, sock_flags, events = SCH_FILE_INPUT;
+  IPSockAddr local_addr;

-  sock_fd = socket(family, SOCK_DGRAM, 0);
+  if (!SCK_IsFamilySupported(family))
+    return INVALID_SOCK_FD;

+  if (!client_only)
+    CNF_GetBindAddress(family, &local_addr.ip_addr);
+  else
+    CNF_GetBindAcquisitionAddress(family, &local_addr.ip_addr);
+
+  if (local_addr.ip_addr.family != family)
+    SCK_GetAnyLocalIPAddress(family, &local_addr.ip_addr);
+
+  local_addr.port = local_port;
+
+  sock_flags = SCK_FLAG_RX_DEST_ADDR | SCK_FLAG_PRIV_BIND;
+  if (!client_only)
+    sock_flags |= SCK_FLAG_BROADCAST;
+
+  sock_fd = SCK_OpenUdpSocket(remote_addr, &local_addr, sock_flags);
  if (sock_fd < 0) {
-    if (!client_only) {
-      LOG(LOGS_ERR, LOGF_NtpIO, "Could not open %s NTP socket : %s",
-          UTI_SockaddrFamilyToString(family), strerror(errno));
-    } else {
-      DEBUG_LOG(LOGF_NtpIO, "Could not open %s NTP socket : %s",
-                UTI_SockaddrFamilyToString(family), strerror(errno));
-    }
+    if (!client_only)
+      LOG(LOGS_ERR, "Could not open NTP socket on %s", UTI_IPSockAddrToString(&local_addr));
    return INVALID_SOCK_FD;
  }

-  /* Close on exec */
-  UTI_FdSetCloexec(sock_fd);
+  if (!client_only && family == IPADDR_INET4 && local_addr.port > 0)
+    bound_server_sock_fd4 = local_addr.ip_addr.addr.in4 != INADDR_ANY;

-  /* Prepare local address */
-  memset(&my_addr, 0, sizeof (my_addr));
-  my_addr_len = 0;
-
-  switch (family) {
-    case AF_INET:
-      if (!client_only)
-        CNF_GetBindAddress(IPADDR_INET4, &bind_address);
-      else
-        CNF_GetBindAcquisitionAddress(IPADDR_INET4, &bind_address);
-
-      if (bind_address.family == IPADDR_INET4)
-        my_addr.in4.sin_addr.s_addr = htonl(bind_address.addr.in4);
-      else if (port_number)
-        my_addr.in4.sin_addr.s_addr = htonl(INADDR_ANY);
-      else
-        break;
-
-      my_addr.in4.sin_family = family;
-      my_addr.in4.sin_port = htons(port_number);
-      my_addr_len = sizeof (my_addr.in4);
-
-      break;
-#ifdef FEAT_IPV6
-    case AF_INET6:
-      if (!client_only)
-        CNF_GetBindAddress(IPADDR_INET6, &bind_address);
-      else
-        CNF_GetBindAcquisitionAddress(IPADDR_INET6, &bind_address);
-
-      if (bind_address.family == IPADDR_INET6)
-        memcpy(my_addr.in6.sin6_addr.s6_addr, bind_address.addr.in6,
-            sizeof (my_addr.in6.sin6_addr.s6_addr));
-      else if (port_number)
-        my_addr.in6.sin6_addr = in6addr_any;
-      else
-        break;
-
-      my_addr.in6.sin6_family = family;
-      my_addr.in6.sin6_port = htons(port_number);
-      my_addr_len = sizeof (my_addr.in6);
-
-      break;
+  /* Enable kernel/HW timestamping of packets */
+#ifdef HAVE_LINUX_TIMESTAMPING
+  if (!NIO_Linux_SetTimestampSocketOptions(sock_fd, client_only, &events))
 #endif
-    default:
-      assert(0);
-  }
+    if (!SCK_EnableKernelRxTimestamping(sock_fd))
+      ;

-  /* Make the socket capable of re-using an old address if binding to a specific port */
-  if (port_number &&
-      setsockopt(sock_fd, SOL_SOCKET, SO_REUSEADDR, (char *)&on_off, sizeof(on_off)) < 0) {
-    LOG(LOGS_ERR, LOGF_NtpIO, "Could not set %s socket option", "SO_REUSEADDR");
-    /* Don't quit - we might survive anyway */
-  }
-  
-  /* Make the socket capable of sending broadcast pkts - needed for NTP broadcast mode */
-  if (!client_only &&
-      setsockopt(sock_fd, SOL_SOCKET, SO_BROADCAST, (char *)&on_off, sizeof(on_off)) < 0) {
-    LOG(LOGS_ERR, LOGF_NtpIO, "Could not set %s socket option", "SO_BROADCAST");
-    /* Don't quit - we might survive anyway */
-  }
-
-#ifdef SO_TIMESTAMP
-  /* Enable receiving of timestamp control messages */
-  if (setsockopt(sock_fd, SOL_SOCKET, SO_TIMESTAMP, (char *)&on_off, sizeof(on_off)) < 0) {
-    LOG(LOGS_ERR, LOGF_NtpIO, "Could not set %s socket option", "SO_TIMESTAMP");
-    /* Don't quit - we might survive anyway */
-  }
-#endif
-
-#ifdef IP_FREEBIND
-  /* Allow binding to address that doesn't exist yet */
-  if (my_addr_len > 0 &&
-      setsockopt(sock_fd, IPPROTO_IP, IP_FREEBIND, (char *)&on_off, sizeof(on_off)) < 0) {
-    LOG(LOGS_ERR, LOGF_NtpIO, "Could not set %s socket option", "IP_FREEBIND");
-  }
-#endif
-
-  if (family == AF_INET) {
-#ifdef HAVE_IN_PKTINFO
-    /* We want the local IP info on server sockets */
-    if (setsockopt(sock_fd, IPPROTO_IP, IP_PKTINFO, (char *)&on_off, sizeof(on_off)) < 0) {
-      LOG(LOGS_ERR, LOGF_NtpIO, "Could not set %s socket option", "IP_PKTINFO");
-      /* Don't quit - we might survive anyway */
-    }
-#endif
-  }
-#ifdef FEAT_IPV6
-  else if (family == AF_INET6) {
-#ifdef IPV6_V6ONLY
-    /* Receive IPv6 packets only */
-    if (setsockopt(sock_fd, IPPROTO_IPV6, IPV6_V6ONLY, (char *)&on_off, sizeof(on_off)) < 0) {
-      LOG(LOGS_ERR, LOGF_NtpIO, "Could not set %s socket option", "IPV6_V6ONLY");
-    }
-#endif
-
-#ifdef HAVE_IN6_PKTINFO
-#ifdef IPV6_RECVPKTINFO
-    if (setsockopt(sock_fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, (char *)&on_off, sizeof(on_off)) < 0) {
-      LOG(LOGS_ERR, LOGF_NtpIO, "Could not set %s socket option", "IPV6_RECVPKTINFO");
-    }
-#else
-    if (setsockopt(sock_fd, IPPROTO_IPV6, IPV6_PKTINFO, (char *)&on_off, sizeof(on_off)) < 0) {
-      LOG(LOGS_ERR, LOGF_NtpIO, "Could not set %s socket option", "IPV6_PKTINFO");
-    }
-#endif
-#endif
-  }
-#endif
-
-  /* Bind the socket if a port or address was specified */
-  if (my_addr_len > 0 && PRV_BindSocket(sock_fd, &my_addr.u, my_addr_len) < 0) {
-    LOG(LOGS_ERR, LOGF_NtpIO, "Could not bind %s NTP socket : %s",
-        UTI_SockaddrFamilyToString(family), strerror(errno));
-    close(sock_fd);
-    return INVALID_SOCK_FD;
-  }
-
-  /* Register handler for read events on the socket */
-  SCH_AddInputFileHandler(sock_fd, read_from_socket, (void *)(long)sock_fd);
+  /* Register handler for read and possibly exception events on the socket */
+  SCH_AddFileHandler(sock_fd, events, read_from_socket, NULL);

  return sock_fd;
 }
@@ -238,40 +129,9 @@ prepare_socket(int family, int port_number, int client_only)
 /* ================================================== */

 static int
-prepare_separate_client_socket(int family)
+open_separate_client_socket(IPSockAddr *remote_addr)
 {
-  switch (family) {
-    case IPADDR_INET4:
-      return prepare_socket(AF_INET, 0, 1);
-#ifdef FEAT_IPV6
-    case IPADDR_INET6:
-      return prepare_socket(AF_INET6, 0, 1);
-#endif
-    default:
-      return INVALID_SOCK_FD;
-  }
-}
-
-/* ================================================== */
-
-static int
-connect_socket(int sock_fd, NTP_Remote_Address *remote_addr)
-{
-  union sockaddr_in46 addr;
-  socklen_t addr_len;
-
-  addr_len = UTI_IPAndPortToSockaddr(&remote_addr->ip_addr, remote_addr->port, &addr.u);
-
-  assert(addr_len);
-
-  if (connect(sock_fd, &addr.u, addr_len) < 0) {
-    DEBUG_LOG(LOGF_NtpIO, "Could not connect NTP socket to %s:%d : %s",
-        UTI_IPToString(&remote_addr->ip_addr), remote_addr->port,
-        strerror(errno));
-    return 0;
-  }
-
-  return 1;
+  return open_socket(remote_addr->ip_addr.family, 0, 1, remote_addr);
 }

 /* ================================================== */
@@ -282,11 +142,15 @@ close_socket(int sock_fd)
  if (sock_fd == INVALID_SOCK_FD)
    return;

-  SCH_RemoveInputFileHandler(sock_fd);
-  close(sock_fd);
+#ifdef HAVE_LINUX_TIMESTAMPING
+  NIO_Linux_NotifySocketClosing(sock_fd);
+#endif
+  SCH_RemoveFileHandler(sock_fd);
+  SCK_CloseSocket(sock_fd);
 }

 /* ================================================== */
+
 void
 NIO_Initialise(int family)
 {
@@ -295,6 +159,20 @@ NIO_Initialise(int family)
  assert(!initialised);
  initialised = 1;

+#ifdef PRIVOPS_BINDSOCKET
+  SCK_SetPrivBind(PRV_BindSocket);
+#endif
+
+#ifdef HAVE_LINUX_TIMESTAMPING
+  NIO_Linux_Initialise();
+#else
+  if (1) {
+    CNF_HwTsInterface *conf_iface;
+    if (CNF_GetHwTsInterface(0, &conf_iface))
+      LOG_FATAL("HW timestamping not supported");
+  }
+#endif
+
  server_port = CNF_GetNTPPort();
  client_port = CNF_GetAcquisitionPort();

@@ -307,48 +185,39 @@ NIO_Initialise(int family)
                                              client_port == server_port);

  server_sock_fd4 = INVALID_SOCK_FD;
-  client_sock_fd4 = INVALID_SOCK_FD;
-  server_sock_ref4 = 0;
-#ifdef FEAT_IPV6
  server_sock_fd6 = INVALID_SOCK_FD;
+  client_sock_fd4 = INVALID_SOCK_FD;
  client_sock_fd6 = INVALID_SOCK_FD;
+  server_sock_ref4 = 0;
  server_sock_ref6 = 0;
-#endif

  if (family == IPADDR_UNSPEC || family == IPADDR_INET4) {
    if (permanent_server_sockets && server_port)
-      server_sock_fd4 = prepare_socket(AF_INET, server_port, 0);
+      server_sock_fd4 = open_socket(IPADDR_INET4, server_port, 0, NULL);
    if (!separate_client_sockets) {
      if (client_port != server_port || !server_port)
-        client_sock_fd4 = prepare_socket(AF_INET, client_port, 1);
+        client_sock_fd4 = open_socket(IPADDR_INET4, client_port, 1, NULL);
      else
        client_sock_fd4 = server_sock_fd4;
    }
  }
-#ifdef FEAT_IPV6
+
  if (family == IPADDR_UNSPEC || family == IPADDR_INET6) {
    if (permanent_server_sockets && server_port)
-      server_sock_fd6 = prepare_socket(AF_INET6, server_port, 0);
+      server_sock_fd6 = open_socket(IPADDR_INET6, server_port, 0, NULL);
    if (!separate_client_sockets) {
      if (client_port != server_port || !server_port)
-        client_sock_fd6 = prepare_socket(AF_INET6, client_port, 1);
+        client_sock_fd6 = open_socket(IPADDR_INET6, client_port, 1, NULL);
      else
        client_sock_fd6 = server_sock_fd6;
    }
  }
-#endif

-  if ((server_port && server_sock_fd4 == INVALID_SOCK_FD &&
-       permanent_server_sockets 
-#ifdef FEAT_IPV6
-       && server_sock_fd6 == INVALID_SOCK_FD
-#endif
-      ) || (!separate_client_sockets && client_sock_fd4 == INVALID_SOCK_FD
-#ifdef FEAT_IPV6
-       && client_sock_fd6 == INVALID_SOCK_FD
-#endif
-      )) {
-    LOG_FATAL(LOGF_NtpIO, "Could not open NTP sockets");
+  if ((server_port && permanent_server_sockets &&
+       server_sock_fd4 == INVALID_SOCK_FD && server_sock_fd6 == INVALID_SOCK_FD) ||
+      (!separate_client_sockets &&
+       client_sock_fd4 == INVALID_SOCK_FD && client_sock_fd6 == INVALID_SOCK_FD)) {
+    LOG_FATAL("Could not open NTP sockets");
  }
 }

@@ -361,12 +230,16 @@ NIO_Finalise(void)
    close_socket(client_sock_fd4);
  close_socket(server_sock_fd4);
  server_sock_fd4 = client_sock_fd4 = INVALID_SOCK_FD;
-#ifdef FEAT_IPV6
+
  if (server_sock_fd6 != client_sock_fd6)
    close_socket(client_sock_fd6);
  close_socket(server_sock_fd6);
  server_sock_fd6 = client_sock_fd6 = INVALID_SOCK_FD;
+
+#ifdef HAVE_LINUX_TIMESTAMPING
+  NIO_Linux_Finalise();
 #endif
+
  initialised = 0;
 }

@@ -376,25 +249,13 @@ int
 NIO_OpenClientSocket(NTP_Remote_Address *remote_addr)
 {
  if (separate_client_sockets) {
-    int sock_fd = prepare_separate_client_socket(remote_addr->ip_addr.family);
-
-    if (sock_fd == INVALID_SOCK_FD)
-      return INVALID_SOCK_FD;
-
-    if (!connect_socket(sock_fd, remote_addr)) {
-      close_socket(sock_fd);
-      return INVALID_SOCK_FD;
-    }
-
-    return sock_fd;
+    return open_separate_client_socket(remote_addr);
  } else {
    switch (remote_addr->ip_addr.family) {
      case IPADDR_INET4:
        return client_sock_fd4;
-#ifdef FEAT_IPV6
      case IPADDR_INET6:
        return client_sock_fd6;
-#endif
      default:
        return INVALID_SOCK_FD;
    }
@@ -411,20 +272,18 @@ NIO_OpenServerSocket(NTP_Remote_Address *remote_addr)
      if (permanent_server_sockets)
        return server_sock_fd4;
      if (server_sock_fd4 == INVALID_SOCK_FD)
-        server_sock_fd4 = prepare_socket(AF_INET, CNF_GetNTPPort(), 0);
+        server_sock_fd4 = open_socket(IPADDR_INET4, CNF_GetNTPPort(), 0, NULL);
      if (server_sock_fd4 != INVALID_SOCK_FD)
        server_sock_ref4++;
      return server_sock_fd4;
-#ifdef FEAT_IPV6
    case IPADDR_INET6:
      if (permanent_server_sockets)
        return server_sock_fd6;
      if (server_sock_fd6 == INVALID_SOCK_FD)
-        server_sock_fd6 = prepare_socket(AF_INET6, CNF_GetNTPPort(), 0);
+        server_sock_fd6 = open_socket(IPADDR_INET6, CNF_GetNTPPort(), 0, NULL);
      if (server_sock_fd6 != INVALID_SOCK_FD)
        server_sock_ref6++;
      return server_sock_fd6;
-#endif
    default:
      return INVALID_SOCK_FD;
  }
@@ -452,16 +311,12 @@ NIO_CloseServerSocket(int sock_fd)
      close_socket(server_sock_fd4);
      server_sock_fd4 = INVALID_SOCK_FD;
    }
-  }
-#ifdef FEAT_IPV6
-  else if (sock_fd == server_sock_fd6) {
+  } else if (sock_fd == server_sock_fd6) {
    if (--server_sock_ref6 <= 0) {
      close_socket(server_sock_fd6);
      server_sock_fd6 = INVALID_SOCK_FD;
    }
-  }
-#endif
-  else {
+  } else {
    assert(0);
  }
 }
@@ -472,228 +327,154 @@ int
 NIO_IsServerSocket(int sock_fd)
 {
  return sock_fd != INVALID_SOCK_FD &&
-    (sock_fd == server_sock_fd4
-#ifdef FEAT_IPV6
-     || sock_fd == server_sock_fd6
-#endif
-    );
+    (sock_fd == server_sock_fd4 || sock_fd == server_sock_fd6);
 }

 /* ================================================== */

-static void
-read_from_socket(void *anything)
+int
+NIO_IsServerSocketOpen(void)
 {
-  /* This should only be called when there is something
-     to read, otherwise it will block. */
-
-  int status, sock_fd;
-  NTP_Receive_Buffer message;
-  union sockaddr_in46 where_from;
-  unsigned int flags = 0;
-  struct timeval now;
-  double now_err;
-  NTP_Remote_Address remote_addr;
-  NTP_Local_Address local_addr;
-  char cmsgbuf[256];
-  struct msghdr msg;
-  struct iovec iov;
-  struct cmsghdr *cmsg;
-
-  assert(initialised);
-
-  SCH_GetLastEventTime(&now, &now_err, NULL);
-
-  iov.iov_base = &message.ntp_pkt;
-  iov.iov_len = sizeof(message);
-  msg.msg_name = &where_from;
-  msg.msg_namelen = sizeof(where_from);
-  msg.msg_iov = &iov;
-  msg.msg_iovlen = 1;
-  msg.msg_control = (void *) cmsgbuf;
-  msg.msg_controllen = sizeof(cmsgbuf);
-  msg.msg_flags = 0;
-
-  sock_fd = (long)anything;
-  status = recvmsg(sock_fd, &msg, flags);
-
-  /* Don't bother checking if read failed or why if it did.  More
-     likely than not, it will be connection refused, resulting from a
-     previous sendto() directing a datagram at a port that is not
-     listening (which appears to generate an ICMP response, and on
-     some architectures e.g. Linux this is translated into an error
-     reponse on a subsequent recvfrom). */
-
-  if (status > 0) {
-    if (msg.msg_namelen > sizeof (where_from))
-      LOG_FATAL(LOGF_NtpIO, "Truncated source address");
-
-    UTI_SockaddrToIPAndPort(&where_from.u, &remote_addr.ip_addr, &remote_addr.port);
-
-    local_addr.ip_addr.family = IPADDR_UNSPEC;
-    local_addr.sock_fd = sock_fd;
-
-    for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
-#ifdef HAVE_IN_PKTINFO
-      if (cmsg->cmsg_level == IPPROTO_IP && cmsg->cmsg_type == IP_PKTINFO) {
-        struct in_pktinfo ipi;
-
-        memcpy(&ipi, CMSG_DATA(cmsg), sizeof(ipi));
-        local_addr.ip_addr.addr.in4 = ntohl(ipi.ipi_spec_dst.s_addr);
-        local_addr.ip_addr.family = IPADDR_INET4;
-      }
-#endif
-
-#ifdef HAVE_IN6_PKTINFO
-      if (cmsg->cmsg_level == IPPROTO_IPV6 && cmsg->cmsg_type == IPV6_PKTINFO) {
-        struct in6_pktinfo ipi;
-
-        memcpy(&ipi, CMSG_DATA(cmsg), sizeof(ipi));
-        memcpy(&local_addr.ip_addr.addr.in6, &ipi.ipi6_addr.s6_addr,
-            sizeof (local_addr.ip_addr.addr.in6));
-        local_addr.ip_addr.family = IPADDR_INET6;
-      }
-#endif
-
-#ifdef SO_TIMESTAMP
-      if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_TIMESTAMP) {
-        struct timeval tv;
-
-        memcpy(&tv, CMSG_DATA(cmsg), sizeof(tv));
-        LCL_CookTime(&tv, &now, &now_err);
-      }
-#endif
-    }
-
-    DEBUG_LOG(LOGF_NtpIO, "Received %d bytes from %s:%d to %s fd %d",
-              status, UTI_IPToString(&remote_addr.ip_addr), remote_addr.port,
-              UTI_IPToString(&local_addr.ip_addr), local_addr.sock_fd);
-
-    if (status >= NTP_NORMAL_PACKET_LENGTH) {
-
-      NSR_ProcessReceive((NTP_Packet *) &message.ntp_pkt, &now, now_err,
-                         &remote_addr, &local_addr, status);
-
-    } else {
-
-      /* Just ignore the packet if it's not of a recognized length */
-
-    }
-  }
+  return server_sock_fd4 != INVALID_SOCK_FD || server_sock_fd6 != INVALID_SOCK_FD;
 }

 /* ================================================== */
-/* Send a packet to remote address from local address */

-static int
-send_packet(void *packet, int packetlen, NTP_Remote_Address *remote_addr, NTP_Local_Address *local_addr)
+int
+NIO_IsServerConnectable(NTP_Remote_Address *remote_addr)
 {
-  union sockaddr_in46 remote;
-  struct msghdr msg;
-  struct iovec iov;
-  char cmsgbuf[256];
-  int cmsglen;
-  socklen_t addrlen = 0;
+  int sock_fd;

-  assert(initialised);
-
-  if (local_addr->sock_fd == INVALID_SOCK_FD) {
-    DEBUG_LOG(LOGF_NtpIO, "No socket to send to %s:%d",
-              UTI_IPToString(&remote_addr->ip_addr), remote_addr->port);
+  sock_fd = open_separate_client_socket(remote_addr);
+  if (sock_fd == INVALID_SOCK_FD)
    return 0;
-  }

-  /* Don't set address with connected socket */
-  if (local_addr->sock_fd == server_sock_fd4 ||
-#ifdef FEAT_IPV6
-      local_addr->sock_fd == server_sock_fd6 ||
-#endif
-      !separate_client_sockets) {
-    addrlen = UTI_IPAndPortToSockaddr(&remote_addr->ip_addr, remote_addr->port,
-                                      &remote.u);
-    if (!addrlen)
-      return 0;
-  }
-
-  if (addrlen) {
-    msg.msg_name = &remote.u;
-    msg.msg_namelen = addrlen;
-  } else {
-    msg.msg_name = NULL;
-    msg.msg_namelen = 0;
-  }
-
-  iov.iov_base = packet;
-  iov.iov_len = packetlen;
-  msg.msg_iov = &iov;
-  msg.msg_iovlen = 1;
-  msg.msg_control = cmsgbuf;
-  msg.msg_controllen = sizeof(cmsgbuf);
-  msg.msg_flags = 0;
-  cmsglen = 0;
-
-#ifdef HAVE_IN_PKTINFO
-  if (local_addr->ip_addr.family == IPADDR_INET4) {
-    struct cmsghdr *cmsg;
-    struct in_pktinfo *ipi;
-
-    cmsg = CMSG_FIRSTHDR(&msg);
-    memset(cmsg, 0, CMSG_SPACE(sizeof(struct in_pktinfo)));
-    cmsglen += CMSG_SPACE(sizeof(struct in_pktinfo));
-
-    cmsg->cmsg_level = IPPROTO_IP;
-    cmsg->cmsg_type = IP_PKTINFO;
-    cmsg->cmsg_len = CMSG_LEN(sizeof(struct in_pktinfo));
-
-    ipi = (struct in_pktinfo *) CMSG_DATA(cmsg);
-    ipi->ipi_spec_dst.s_addr = htonl(local_addr->ip_addr.addr.in4);
-  }
-#endif
-
-#ifdef HAVE_IN6_PKTINFO
-  if (local_addr->ip_addr.family == IPADDR_INET6) {
-    struct cmsghdr *cmsg;
-    struct in6_pktinfo *ipi;
-
-    cmsg = CMSG_FIRSTHDR(&msg);
-    memset(cmsg, 0, CMSG_SPACE(sizeof(struct in6_pktinfo)));
-    cmsglen += CMSG_SPACE(sizeof(struct in6_pktinfo));
-
-    cmsg->cmsg_level = IPPROTO_IPV6;
-    cmsg->cmsg_type = IPV6_PKTINFO;
-    cmsg->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));
-
-    ipi = (struct in6_pktinfo *) CMSG_DATA(cmsg);
-    memcpy(&ipi->ipi6_addr.s6_addr, &local_addr->ip_addr.addr.in6,
-        sizeof(ipi->ipi6_addr.s6_addr));
-  }
-#endif
-
-  msg.msg_controllen = cmsglen;
-  /* This is apparently required on some systems */
-  if (!cmsglen)
-    msg.msg_control = NULL;
-
-  if (sendmsg(local_addr->sock_fd, &msg, 0) < 0) {
-    DEBUG_LOG(LOGF_NtpIO, "Could not send to %s:%d from %s fd %d : %s",
-        UTI_IPToString(&remote_addr->ip_addr), remote_addr->port,
-        UTI_IPToString(&local_addr->ip_addr), local_addr->sock_fd,
-        strerror(errno));
-    return 0;
-  }
-
-  DEBUG_LOG(LOGF_NtpIO, "Sent %d bytes to %s:%d from %s fd %d", packetlen,
-      UTI_IPToString(&remote_addr->ip_addr), remote_addr->port,
-      UTI_IPToString(&local_addr->ip_addr), local_addr->sock_fd);
+  close_socket(sock_fd);

  return 1;
 }

 /* ================================================== */
-/* Send a packet to a given address */
+
+static void
+process_message(SCK_Message *message, int sock_fd, int event)
+{
+  NTP_Local_Address local_addr;
+  NTP_Local_Timestamp local_ts;
+  struct timespec sched_ts;
+
+  SCH_GetLastEventTime(&local_ts.ts, &local_ts.err, NULL);
+  local_ts.source = NTP_TS_DAEMON;
+  sched_ts = local_ts.ts;
+
+  if (message->addr_type != SCK_ADDR_IP) {
+    DEBUG_LOG("Unexpected address type");
+    return;
+  }
+
+  local_addr.ip_addr = message->local_addr.ip;
+  local_addr.if_index = message->if_index;;
+  local_addr.sock_fd = sock_fd;
+
+#ifdef HAVE_LINUX_TIMESTAMPING
+  if (NIO_Linux_ProcessMessage(message, &local_addr, &local_ts, event))
+    return;
+#else
+  if (!UTI_IsZeroTimespec(&message->timestamp.kernel)) {
+    LCL_CookTime(&message->timestamp.kernel, &local_ts.ts, &local_ts.err);
+    local_ts.source = NTP_TS_KERNEL;
+  }
+#endif
+
+  if (local_ts.source != NTP_TS_DAEMON)
+    DEBUG_LOG("Updated RX timestamp delay=%.9f tss=%u",
+              UTI_DiffTimespecsToDouble(&sched_ts, &local_ts.ts), local_ts.source);
+
+  /* Just ignore the packet if it's not of a recognized length */
+  if (message->length < NTP_HEADER_LENGTH || message->length > sizeof (NTP_Packet)) {
+    DEBUG_LOG("Unexpected length");
+    return;
+  }
+
+  NSR_ProcessRx(&message->remote_addr.ip, &local_addr, &local_ts, message->data, message->length);
+}
+
+/* ================================================== */
+
+static void
+read_from_socket(int sock_fd, int event, void *anything)
+{
+  /* This should only be called when there is something
+     to read, otherwise it may block */
+
+  SCK_Message messages[SCK_MAX_RECV_MESSAGES];
+  int i, received, flags = 0;
+
+#ifdef HAVE_LINUX_TIMESTAMPING
+  if (NIO_Linux_ProcessEvent(sock_fd, event))
+    return;
+#endif
+
+  if (event == SCH_FILE_EXCEPTION) {
+#ifdef HAVE_LINUX_TIMESTAMPING
+    flags |= SCK_FLAG_MSG_ERRQUEUE;
+#else
+    assert(0);
+#endif
+  }
+
+  received = SCK_ReceiveMessages(sock_fd, messages, SCK_MAX_RECV_MESSAGES, flags);
+  if (received <= 0)
+    return;
+
+  for (i = 0; i < received; i++)
+    process_message(&messages[i], sock_fd, event);
+}
+
+/* ================================================== */
+/* Send a packet to remote address from local address */

 int
-NIO_SendPacket(NTP_Packet *packet, NTP_Remote_Address *remote_addr, NTP_Local_Address *local_addr, int length)
+NIO_SendPacket(NTP_Packet *packet, NTP_Remote_Address *remote_addr,
+               NTP_Local_Address *local_addr, int length, int process_tx)
 {
-  return send_packet((void *) packet, length, remote_addr, local_addr);
+  SCK_Message message;
+
+  assert(initialised);
+
+  if (local_addr->sock_fd == INVALID_SOCK_FD) {
+    DEBUG_LOG("No socket to send to %s", UTI_IPSockAddrToString(remote_addr));
+    return 0;
+  }
+
+  SCK_InitMessage(&message, SCK_ADDR_IP);
+
+  message.data = packet;
+  message.length = length;
+
+  /* Specify remote address if the socket is not connected */
+  if (NIO_IsServerSocket(local_addr->sock_fd) || !separate_client_sockets) {
+    message.remote_addr.ip.ip_addr = remote_addr->ip_addr;
+    message.remote_addr.ip.port = remote_addr->port;
+  }
+
+  message.if_index = local_addr->if_index;
+  message.local_addr.ip = local_addr->ip_addr;
+
+#if !defined(HAVE_IN_PKTINFO) && defined(IP_SENDSRCADDR)
+  /* On FreeBSD a local IPv4 address cannot be specified on bound socket */
+  if (message.local_addr.ip.family == IPADDR_INET4 &&
+      (local_addr->sock_fd != server_sock_fd4 || bound_server_sock_fd4))
+    message.local_addr.ip.family = IPADDR_UNSPEC;
+#endif
+
+#ifdef HAVE_LINUX_TIMESTAMPING
+  if (process_tx)
+    NIO_Linux_RequestTxTimestamp(&message, local_addr->sock_fd);
+#endif
+
+  if (!SCK_SendMessage(local_addr->sock_fd, &message, 0))
+    return 0;
+
+  return 1;
 }
--- a/ntp_io.h
+++ b/ntp_io.h
@@ -53,7 +53,14 @@ extern void NIO_CloseServerSocket(int sock_fd);
 /* Function to check if socket is a server socket */
 extern int NIO_IsServerSocket(int sock_fd);

+/* Function to check if a server socket is currently open */
+extern int NIO_IsServerSocketOpen(void);
+
+/* Function to check if client packets can be sent to a server */
+extern int NIO_IsServerConnectable(NTP_Remote_Address *remote_addr);
+
 /* Function to transmit a packet */
-extern int NIO_SendPacket(NTP_Packet *packet, NTP_Remote_Address *remote_addr, NTP_Local_Address *local_addr, int length);
+extern int NIO_SendPacket(NTP_Packet *packet, NTP_Remote_Address *remote_addr,
+                          NTP_Local_Address *local_addr, int length, int process_tx);

 #endif /* GOT_NTP_IO_H */
--- a/ntp_io_linux.c
+++ b/ntp_io_linux.c
@@ -0,0 +1,813 @@
+/*
+  chronyd/chronyc - Programs for keeping computer clocks accurate.
+
+ **********************************************************************
+ * Copyright (C) Miroslav Lichvar  2016-2019
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ * 
+ **********************************************************************
+
+  =======================================================================
+
+  Functions for NTP I/O specific to Linux
+  */
+
+#include "config.h"
+
+#include "sysincl.h"
+
+#include <ifaddrs.h>
+#include <linux/ethtool.h>
+#include <linux/net_tstamp.h>
+#include <linux/sockios.h>
+#include <net/if.h>
+
+#include "array.h"
+#include "conf.h"
+#include "hwclock.h"
+#include "local.h"
+#include "logging.h"
+#include "ntp_core.h"
+#include "ntp_io.h"
+#include "ntp_io_linux.h"
+#include "ntp_sources.h"
+#include "sched.h"
+#include "socket.h"
+#include "sys_linux.h"
+#include "util.h"
+
+struct Interface {
+  char name[IF_NAMESIZE];
+  int if_index;
+  int phc_fd;
+  int phc_mode;
+  int phc_nocrossts;
+  /* Link speed in mbit/s */
+  int link_speed;
+  /* Start of UDP data at layer 2 for IPv4 and IPv6 */
+  int l2_udp4_ntp_start;
+  int l2_udp6_ntp_start;
+  /* Precision of PHC readings */
+  double precision;
+  /* Compensation of errors in TX and RX timestamping */
+  double tx_comp;
+  double rx_comp;
+  HCL_Instance clock;
+};
+
+/* Number of PHC readings per HW clock sample */
+#define PHC_READINGS 10
+
+/* Minimum interval between PHC readings */
+#define MIN_PHC_POLL -6
+
+/* Maximum acceptable offset between HW and daemon/kernel timestamp */
+#define MAX_TS_DELAY 1.0
+
+/* Array of Interfaces */
+static ARR_Instance interfaces;
+
+/* RX/TX and TX-specific timestamping socket options */
+static int ts_flags;
+static int ts_tx_flags;
+
+/* Flag indicating the socket options can't be changed in control messages */
+static int permanent_ts_options;
+
+/* When sending client requests to a close and fast server, it is possible that
+   a response will be received before the HW transmit timestamp of the request
+   itself.  To avoid processing of the response without the HW timestamp, we
+   monitor events returned by select() and suspend reading of packets from the
+   receive queue for up to 200 microseconds.  As the requests are normally
+   separated by at least 200 milliseconds, it is sufficient to monitor and
+   suspend one socket at a time. */
+static int monitored_socket;
+static int suspended_socket;
+static SCH_TimeoutID resume_timeout_id;
+
+#define RESUME_TIMEOUT 200.0e-6
+
+/* Unbound socket keeping the kernel RX timestamping permanently enabled
+   in order to avoid a race condition between receiving a server response
+   and the kernel actually starting to timestamp received packets after
+   enabling the timestamping and sending a request */
+static int dummy_rxts_socket;
+
+#define INVALID_SOCK_FD -3
+
+/* ================================================== */
+
+static int
+add_interface(CNF_HwTsInterface *conf_iface)
+{
+  struct ethtool_ts_info ts_info;
+  struct hwtstamp_config ts_config;
+  struct ifreq req;
+  int sock_fd, if_index, phc_fd, req_hwts_flags, rx_filter;
+  unsigned int i;
+  struct Interface *iface;
+
+  /* Check if the interface was not already added */
+  for (i = 0; i < ARR_GetSize(interfaces); i++) {
+    if (!strcmp(conf_iface->name, ((struct Interface *)ARR_GetElement(interfaces, i))->name))
+      return 1;
+  }
+
+  sock_fd = SCK_OpenUdpSocket(NULL, NULL, 0);
+  if (sock_fd < 0)
+    return 0;
+
+  memset(&req, 0, sizeof (req));
+  memset(&ts_info, 0, sizeof (ts_info));
+
+  if (snprintf(req.ifr_name, sizeof (req.ifr_name), "%s", conf_iface->name) >=
+      sizeof (req.ifr_name)) {
+    SCK_CloseSocket(sock_fd);
+    return 0;
+  }
+
+  if (ioctl(sock_fd, SIOCGIFINDEX, &req)) {
+    DEBUG_LOG("ioctl(%s) failed : %s", "SIOCGIFINDEX", strerror(errno));
+    SCK_CloseSocket(sock_fd);
+    return 0;
+  }
+
+  if_index = req.ifr_ifindex;
+
+  ts_info.cmd = ETHTOOL_GET_TS_INFO;
+  req.ifr_data = (char *)&ts_info;
+
+  if (ioctl(sock_fd, SIOCETHTOOL, &req)) {
+    DEBUG_LOG("ioctl(%s) failed : %s", "SIOCETHTOOL", strerror(errno));
+    SCK_CloseSocket(sock_fd);
+    return 0;
+  }
+
+  req_hwts_flags = SOF_TIMESTAMPING_RX_HARDWARE | SOF_TIMESTAMPING_TX_HARDWARE |
+                   SOF_TIMESTAMPING_RAW_HARDWARE;
+  if ((ts_info.so_timestamping & req_hwts_flags) != req_hwts_flags) {
+    DEBUG_LOG("HW timestamping not supported on %s", req.ifr_name);
+    SCK_CloseSocket(sock_fd);
+    return 0;
+  }
+
+  if (ts_info.phc_index < 0) {
+    DEBUG_LOG("PHC missing on %s", req.ifr_name);
+    SCK_CloseSocket(sock_fd);
+    return 0;
+  }
+
+  switch (conf_iface->rxfilter) {
+    case CNF_HWTS_RXFILTER_ANY:
+#ifdef HAVE_LINUX_TIMESTAMPING_RXFILTER_NTP
+      if (ts_info.rx_filters & (1 << HWTSTAMP_FILTER_NTP_ALL))
+        rx_filter = HWTSTAMP_FILTER_NTP_ALL;
+      else
+#endif
+      if (ts_info.rx_filters & (1 << HWTSTAMP_FILTER_ALL))
+        rx_filter = HWTSTAMP_FILTER_ALL;
+      else
+        rx_filter = HWTSTAMP_FILTER_NONE;
+      break;
+    case CNF_HWTS_RXFILTER_NONE:
+      rx_filter = HWTSTAMP_FILTER_NONE;
+      break;
+#ifdef HAVE_LINUX_TIMESTAMPING_RXFILTER_NTP
+    case CNF_HWTS_RXFILTER_NTP:
+      rx_filter = HWTSTAMP_FILTER_NTP_ALL;
+      break;
+#endif
+    default:
+      rx_filter = HWTSTAMP_FILTER_ALL;
+      break;
+  }
+
+  ts_config.flags = 0;
+  ts_config.tx_type = HWTSTAMP_TX_ON;
+  ts_config.rx_filter = rx_filter;
+  req.ifr_data = (char *)&ts_config;
+
+  if (ioctl(sock_fd, SIOCSHWTSTAMP, &req)) {
+    DEBUG_LOG("ioctl(%s) failed : %s", "SIOCSHWTSTAMP", strerror(errno));
+
+    /* Check the current timestamping configuration in case this interface
+       allows only reading of the configuration and it was already configured
+       as requested */
+    req.ifr_data = (char *)&ts_config;
+#ifdef SIOCGHWTSTAMP
+    if (ioctl(sock_fd, SIOCGHWTSTAMP, &req) ||
+        ts_config.tx_type != HWTSTAMP_TX_ON || ts_config.rx_filter != rx_filter)
+#endif
+    {
+      SCK_CloseSocket(sock_fd);
+      return 0;
+    }
+  }
+
+  SCK_CloseSocket(sock_fd);
+
+  phc_fd = SYS_Linux_OpenPHC(NULL, ts_info.phc_index);
+  if (phc_fd < 0)
+    return 0;
+
+  iface = ARR_GetNewElement(interfaces);
+
+  snprintf(iface->name, sizeof (iface->name), "%s", conf_iface->name);
+  iface->if_index = if_index;
+  iface->phc_fd = phc_fd;
+  iface->phc_mode = 0;
+  iface->phc_nocrossts = conf_iface->nocrossts;
+
+  /* Start with 1 gbit and no VLANs or IPv4/IPv6 options */
+  iface->link_speed = 1000;
+  iface->l2_udp4_ntp_start = 42;
+  iface->l2_udp6_ntp_start = 62;
+
+  iface->precision = conf_iface->precision;
+  iface->tx_comp = conf_iface->tx_comp;
+  iface->rx_comp = conf_iface->rx_comp;
+
+  iface->clock = HCL_CreateInstance(conf_iface->min_samples, conf_iface->max_samples,
+                                    UTI_Log2ToDouble(MAX(conf_iface->minpoll, MIN_PHC_POLL)));
+
+  LOG(LOGS_INFO, "Enabled HW timestamping %son %s",
+      ts_config.rx_filter == HWTSTAMP_FILTER_NONE ? "(TX only) " : "", iface->name);
+
+  return 1;
+}
+
+/* ================================================== */
+
+static int
+add_all_interfaces(CNF_HwTsInterface *conf_iface_all)
+{
+  CNF_HwTsInterface conf_iface;
+  struct ifaddrs *ifaddr, *ifa;
+  int r;
+
+  conf_iface = *conf_iface_all;
+
+  if (getifaddrs(&ifaddr)) {
+    DEBUG_LOG("getifaddrs() failed : %s", strerror(errno));
+    return 0;
+  }
+
+  for (r = 0, ifa = ifaddr; ifa; ifa = ifa->ifa_next) {
+    conf_iface.name = ifa->ifa_name;
+    if (add_interface(&conf_iface))
+      r = 1;
+  }
+  
+  freeifaddrs(ifaddr);
+
+  /* Return success if at least one interface was added */
+  return r;
+}
+
+/* ================================================== */
+
+static void
+update_interface_speed(struct Interface *iface)
+{
+  struct ethtool_cmd cmd;
+  struct ifreq req;
+  int sock_fd, link_speed;
+
+  sock_fd = SCK_OpenUdpSocket(NULL, NULL, 0);
+  if (sock_fd < 0)
+    return;
+
+  memset(&req, 0, sizeof (req));
+  memset(&cmd, 0, sizeof (cmd));
+
+  snprintf(req.ifr_name, sizeof (req.ifr_name), "%s", iface->name);
+  cmd.cmd = ETHTOOL_GSET;
+  req.ifr_data = (char *)&cmd;
+
+  if (ioctl(sock_fd, SIOCETHTOOL, &req)) {
+    DEBUG_LOG("ioctl(%s) failed : %s", "SIOCETHTOOL", strerror(errno));
+    SCK_CloseSocket(sock_fd);
+    return;
+  }
+
+  SCK_CloseSocket(sock_fd);
+
+  link_speed = ethtool_cmd_speed(&cmd);
+
+  if (iface->link_speed != link_speed) {
+    iface->link_speed = link_speed;
+    DEBUG_LOG("Updated speed of %s to %d Mb/s", iface->name, link_speed);
+  }
+}
+
+/* ================================================== */
+
+#if defined(HAVE_LINUX_TIMESTAMPING_OPT_PKTINFO) || defined(HAVE_LINUX_TIMESTAMPING_OPT_TX_SWHW)
+static int
+check_timestamping_option(int option)
+{
+  int sock_fd;
+
+  sock_fd = SCK_OpenUdpSocket(NULL, NULL, 0);
+  if (sock_fd < 0)
+    return 0;
+
+  if (!SCK_SetIntOption(sock_fd, SOL_SOCKET, SO_TIMESTAMPING, option)) {
+    SCK_CloseSocket(sock_fd);
+    return 0;
+  }
+
+  SCK_CloseSocket(sock_fd);
+  return 1;
+}
+#endif
+
+/* ================================================== */
+
+static int
+open_dummy_socket(void)
+{
+  int sock_fd, events = 0;
+
+  sock_fd = SCK_OpenUdpSocket(NULL, NULL, 0);
+  if (sock_fd < 0)
+    return INVALID_SOCK_FD;
+
+  if (!NIO_Linux_SetTimestampSocketOptions(sock_fd, 1, &events)) {
+    SCK_CloseSocket(sock_fd);
+    return INVALID_SOCK_FD;
+  }
+
+  return sock_fd;
+}
+
+/* ================================================== */
+
+void
+NIO_Linux_Initialise(void)
+{
+  CNF_HwTsInterface *conf_iface;
+  unsigned int i;
+  int hwts;
+
+  interfaces = ARR_CreateInstance(sizeof (struct Interface));
+
+  /* Enable HW timestamping on specified interfaces.  If "*" was specified, try
+     all interfaces.  If no interface was specified, enable SW timestamping. */
+
+  for (i = hwts = 0; CNF_GetHwTsInterface(i, &conf_iface); i++) {
+    if (!strcmp("*", conf_iface->name))
+      continue;
+    if (!add_interface(conf_iface))
+      LOG_FATAL("Could not enable HW timestamping on %s", conf_iface->name);
+    hwts = 1;
+  }
+
+  for (i = 0; CNF_GetHwTsInterface(i, &conf_iface); i++) {
+    if (strcmp("*", conf_iface->name))
+      continue;
+    if (add_all_interfaces(conf_iface))
+      hwts = 1;
+    break;
+  }
+
+  ts_flags = SOF_TIMESTAMPING_SOFTWARE | SOF_TIMESTAMPING_RX_SOFTWARE;
+  ts_tx_flags = SOF_TIMESTAMPING_TX_SOFTWARE;
+
+  if (hwts) {
+    ts_flags |= SOF_TIMESTAMPING_RAW_HARDWARE | SOF_TIMESTAMPING_RX_HARDWARE;
+    ts_tx_flags |= SOF_TIMESTAMPING_TX_HARDWARE;
+#ifdef HAVE_LINUX_TIMESTAMPING_OPT_PKTINFO
+    if (check_timestamping_option(SOF_TIMESTAMPING_OPT_PKTINFO))
+      ts_flags |= SOF_TIMESTAMPING_OPT_PKTINFO;
+#endif
+#ifdef HAVE_LINUX_TIMESTAMPING_OPT_TX_SWHW
+    if (check_timestamping_option(SOF_TIMESTAMPING_OPT_TX_SWHW))
+      ts_flags |= SOF_TIMESTAMPING_OPT_TX_SWHW;
+#endif
+  }
+
+  /* Enable IP_PKTINFO in messages looped back to the error queue */
+  ts_flags |= SOF_TIMESTAMPING_OPT_CMSG;
+
+  /* Kernels before 4.7 ignore timestamping flags set in control messages */
+  permanent_ts_options = !SYS_Linux_CheckKernelVersion(4, 7);
+
+  monitored_socket = INVALID_SOCK_FD;
+  suspended_socket = INVALID_SOCK_FD;
+  dummy_rxts_socket = INVALID_SOCK_FD;
+}
+
+/* ================================================== */
+
+void
+NIO_Linux_Finalise(void)
+{
+  struct Interface *iface;
+  unsigned int i;
+
+  if (dummy_rxts_socket != INVALID_SOCK_FD)
+    SCK_CloseSocket(dummy_rxts_socket);
+
+  for (i = 0; i < ARR_GetSize(interfaces); i++) {
+    iface = ARR_GetElement(interfaces, i);
+    HCL_DestroyInstance(iface->clock);
+    close(iface->phc_fd);
+  }
+
+  ARR_DestroyInstance(interfaces);
+}
+
+/* ================================================== */
+
+int
+NIO_Linux_SetTimestampSocketOptions(int sock_fd, int client_only, int *events)
+{
+  int val, flags;
+
+  if (!ts_flags)
+    return 0;
+
+  /* Enable SCM_TIMESTAMPING control messages and the socket's error queue in
+     order to receive our transmitted packets with more accurate timestamps */
+
+  val = 1;
+  flags = ts_flags;
+
+  if (client_only || permanent_ts_options)
+    flags |= ts_tx_flags;
+
+  if (!SCK_SetIntOption(sock_fd, SOL_SOCKET, SO_SELECT_ERR_QUEUE, val)) {
+    ts_flags = 0;
+    return 0;
+  }
+
+  if (!SCK_SetIntOption(sock_fd, SOL_SOCKET, SO_TIMESTAMPING, flags)) {
+    ts_flags = 0;
+    return 0;
+  }
+
+  *events |= SCH_FILE_EXCEPTION;
+  return 1;
+}
+
+/* ================================================== */
+
+static void
+resume_socket(int sock_fd)
+{
+  if (monitored_socket == sock_fd)
+    monitored_socket = INVALID_SOCK_FD;
+
+  if (sock_fd == INVALID_SOCK_FD || sock_fd != suspended_socket)
+    return;
+
+  suspended_socket = INVALID_SOCK_FD;
+
+  SCH_SetFileHandlerEvent(sock_fd, SCH_FILE_INPUT, 1);
+
+  DEBUG_LOG("Resumed RX processing %s timeout fd=%d",
+            resume_timeout_id ? "before" : "on", sock_fd);
+
+  if (resume_timeout_id) {
+    SCH_RemoveTimeout(resume_timeout_id);
+    resume_timeout_id = 0;
+  }
+}
+
+/* ================================================== */
+
+static void
+resume_timeout(void *arg)
+{
+  resume_timeout_id = 0;
+  resume_socket(suspended_socket);
+}
+
+/* ================================================== */
+
+static void
+suspend_socket(int sock_fd)
+{
+  resume_socket(suspended_socket);
+
+  suspended_socket = sock_fd;
+
+  SCH_SetFileHandlerEvent(suspended_socket, SCH_FILE_INPUT, 0);
+  resume_timeout_id = SCH_AddTimeoutByDelay(RESUME_TIMEOUT, resume_timeout, NULL);
+
+  DEBUG_LOG("Suspended RX processing fd=%d", sock_fd);
+}
+
+/* ================================================== */
+
+int
+NIO_Linux_ProcessEvent(int sock_fd, int event)
+{
+  if (sock_fd != monitored_socket)
+    return 0;
+
+  if (event == SCH_FILE_INPUT) {
+    suspend_socket(monitored_socket);
+    monitored_socket = INVALID_SOCK_FD;
+
+    /* Don't process the message yet */
+    return 1;
+  }
+
+  return 0;
+}
+
+/* ================================================== */
+
+static struct Interface *
+get_interface(int if_index)
+{
+  struct Interface *iface;
+  unsigned int i;
+
+  for (i = 0; i < ARR_GetSize(interfaces); i++) {
+    iface = ARR_GetElement(interfaces, i);
+    if (iface->if_index != if_index)
+      continue;
+
+    return iface;
+  }
+
+  return NULL;
+}
+
+/* ================================================== */
+
+static void
+process_hw_timestamp(struct Interface *iface, struct timespec *hw_ts,
+                     NTP_Local_Timestamp *local_ts, int rx_ntp_length, int family,
+                     int l2_length)
+{
+  struct timespec sample_phc_ts, sample_sys_ts, sample_local_ts, ts;
+  double rx_correction, ts_delay, phc_err, local_err;
+
+  if (HCL_NeedsNewSample(iface->clock, &local_ts->ts)) {
+    if (!SYS_Linux_GetPHCSample(iface->phc_fd, iface->phc_nocrossts, iface->precision,
+                                &iface->phc_mode, &sample_phc_ts, &sample_sys_ts,
+                                &phc_err))
+      return;
+
+    LCL_CookTime(&sample_sys_ts, &sample_local_ts, &local_err);
+    HCL_AccumulateSample(iface->clock, &sample_phc_ts, &sample_local_ts,
+                         phc_err + local_err);
+
+    update_interface_speed(iface);
+  }
+
+  /* We need to transpose RX timestamps as hardware timestamps are normally
+     preamble timestamps and RX timestamps in NTP are supposed to be trailer
+     timestamps.  If we don't know the length of the packet at layer 2, we
+     make an assumption that UDP data start at the same position as in the
+     last transmitted packet which had a HW TX timestamp. */
+  if (rx_ntp_length && iface->link_speed) {
+    if (!l2_length)
+      l2_length = (family == IPADDR_INET4 ? iface->l2_udp4_ntp_start :
+                   iface->l2_udp6_ntp_start) + rx_ntp_length;
+
+    /* Include the frame check sequence (FCS) */
+    l2_length += 4;
+
+    rx_correction = l2_length / (1.0e6 / 8 * iface->link_speed);
+
+    UTI_AddDoubleToTimespec(hw_ts, rx_correction, hw_ts);
+  }
+
+  if (!HCL_CookTime(iface->clock, hw_ts, &ts, &local_err))
+    return;
+
+  if (!rx_ntp_length && iface->tx_comp)
+    UTI_AddDoubleToTimespec(&ts, iface->tx_comp, &ts);
+  else if (rx_ntp_length && iface->rx_comp)
+    UTI_AddDoubleToTimespec(&ts, -iface->rx_comp, &ts);
+
+  ts_delay = UTI_DiffTimespecsToDouble(&local_ts->ts, &ts);
+
+  if (fabs(ts_delay) > MAX_TS_DELAY) {
+    DEBUG_LOG("Unacceptable timestamp delay %.9f", ts_delay);
+    return;
+  }
+
+  local_ts->ts = ts;
+  local_ts->err = local_err;
+  local_ts->source = NTP_TS_HARDWARE;
+}
+
+/* ================================================== */
+/* Extract UDP data from a layer 2 message.  Supported is Ethernet
+   with optional VLAN tags. */
+
+static int
+extract_udp_data(unsigned char *msg, NTP_Remote_Address *remote_addr, int len)
+{
+  unsigned char *msg_start = msg;
+
+  remote_addr->ip_addr.family = IPADDR_UNSPEC;
+  remote_addr->port = 0;
+
+  /* Skip MACs */
+  if (len < 12)
+    return 0;
+  len -= 12, msg += 12;
+
+  /* Skip VLAN tag(s) if present */
+  while (len >= 4 && msg[0] == 0x81 && msg[1] == 0x00)
+    len -= 4, msg += 4;
+
+  /* Skip IPv4 or IPv6 ethertype */
+  if (len < 2 || !((msg[0] == 0x08 && msg[1] == 0x00) ||
+                   (msg[0] == 0x86 && msg[1] == 0xdd)))
+    return 0;
+  len -= 2, msg += 2;
+
+  /* Parse destination address and port from IPv4/IPv6 and UDP headers */
+  if (len >= 20 && msg[0] >> 4 == 4) {
+    int ihl = (msg[0] & 0xf) * 4;
+    uint32_t addr;
+
+    if (len < ihl + 8 || msg[9] != 17)
+      return 0;
+
+    memcpy(&addr, msg + 16, sizeof (addr));
+    remote_addr->ip_addr.addr.in4 = ntohl(addr);
+    remote_addr->port = ntohs(*(uint16_t *)(msg + ihl + 2));
+    remote_addr->ip_addr.family = IPADDR_INET4;
+    len -= ihl + 8, msg += ihl + 8;
+#ifdef FEAT_IPV6
+  } else if (len >= 48 && msg[0] >> 4 == 6) {
+    int eh_len, next_header = msg[6];
+
+    memcpy(&remote_addr->ip_addr.addr.in6, msg + 24, sizeof (remote_addr->ip_addr.addr.in6));
+    len -= 40, msg += 40;
+
+    /* Skip IPv6 extension headers if present */
+    while (next_header != 17) {
+      switch (next_header) {
+        case 44:  /* Fragment Header */
+          /* Process only the first fragment */
+          if (ntohs(*(uint16_t *)(msg + 2)) >> 3 != 0)
+            return 0;
+          eh_len = 8;
+          break;
+        case 0:   /* Hop-by-Hop Options */
+        case 43:  /* Routing Header */
+        case 60:  /* Destination Options */
+        case 135: /* Mobility Header */
+          eh_len = 8 * (msg[1] + 1);
+          break;
+        case 51:  /* Authentication Header */
+          eh_len = 4 * (msg[1] + 2);
+          break;
+        default:
+          return 0;
+      }
+
+      if (eh_len < 8 || len < eh_len + 8)
+        return 0;
+
+      next_header = msg[0];
+      len -= eh_len, msg += eh_len;
+    }
+
+    remote_addr->port = ntohs(*(uint16_t *)(msg + 2));
+    remote_addr->ip_addr.family = IPADDR_INET6;
+    len -= 8, msg += 8;
+#endif
+  } else {
+    return 0;
+  }
+
+  /* Move the message to fix alignment of its fields */
+  if (len > 0)
+    memmove(msg_start, msg, len);
+
+  return len;
+}
+
+/* ================================================== */
+
+int
+NIO_Linux_ProcessMessage(SCK_Message *message, NTP_Local_Address *local_addr,
+                         NTP_Local_Timestamp *local_ts, int event)
+{
+  struct Interface *iface;
+  int is_tx, ts_if_index, l2_length;
+
+  is_tx = event == SCH_FILE_EXCEPTION;
+  iface = NULL;
+
+  ts_if_index = message->timestamp.if_index;
+  if (ts_if_index == INVALID_IF_INDEX)
+    ts_if_index = message->if_index;
+  l2_length = message->timestamp.l2_length;
+
+  if (!UTI_IsZeroTimespec(&message->timestamp.hw)) {
+    iface = get_interface(ts_if_index);
+    if (iface) {
+      process_hw_timestamp(iface, &message->timestamp.hw, local_ts, !is_tx ? message->length : 0,
+                           message->remote_addr.ip.ip_addr.family, l2_length);
+    } else {
+      DEBUG_LOG("HW clock not found for interface %d", ts_if_index);
+    }
+
+    /* If a HW transmit timestamp was received, resume processing
+       of non-error messages on this socket */
+    if (is_tx)
+      resume_socket(local_addr->sock_fd);
+  }
+
+  if (local_ts->source == NTP_TS_DAEMON && !UTI_IsZeroTimespec(&message->timestamp.kernel) &&
+      (!is_tx || UTI_IsZeroTimespec(&message->timestamp.hw))) {
+    LCL_CookTime(&message->timestamp.kernel, &local_ts->ts, &local_ts->err);
+    local_ts->source = NTP_TS_KERNEL;
+  }
+
+  /* If the kernel is slow with enabling RX timestamping, open a dummy
+     socket to keep the kernel RX timestamping permanently enabled */
+  if (!is_tx && local_ts->source == NTP_TS_DAEMON && ts_flags) {
+    DEBUG_LOG("Missing kernel RX timestamp");
+    if (dummy_rxts_socket == INVALID_SOCK_FD)
+      dummy_rxts_socket = open_dummy_socket();
+  }
+
+  /* Return the message if it's not received from the error queue */
+  if (!is_tx)
+    return 0;
+
+  /* The data from the error queue includes all layers up to UDP.  We have to
+     extract the UDP data and also the destination address with port as there
+     currently doesn't seem to be a better way to get them both. */
+  l2_length = message->length;
+  message->length = extract_udp_data(message->data, &message->remote_addr.ip, message->length);
+
+  DEBUG_LOG("Extracted message for %s fd=%d len=%u",
+            UTI_IPSockAddrToString(&message->remote_addr.ip),
+            local_addr->sock_fd, message->length);
+
+  /* Update assumed position of UDP data at layer 2 for next received packet */
+  if (iface && message->length) {
+    if (message->remote_addr.ip.ip_addr.family == IPADDR_INET4)
+      iface->l2_udp4_ntp_start = l2_length - message->length;
+    else if (message->remote_addr.ip.ip_addr.family == IPADDR_INET6)
+      iface->l2_udp6_ntp_start = l2_length - message->length;
+  }
+
+  /* Drop the message if it has no timestamp or its processing failed */
+  if (local_ts->source == NTP_TS_DAEMON) {
+    DEBUG_LOG("Missing TX timestamp");
+    return 1;
+  }
+
+  if (message->length < NTP_HEADER_LENGTH)
+    return 1;
+
+  NSR_ProcessTx(&message->remote_addr.ip, local_addr, local_ts, message->data, message->length);
+
+  return 1;
+}
+
+/* ================================================== */
+
+void
+NIO_Linux_RequestTxTimestamp(SCK_Message *message, int sock_fd)
+{
+  if (!ts_flags)
+    return;
+
+  /* If a HW transmit timestamp is requested on a client socket, monitor
+     events on the socket in order to avoid processing of a fast response
+     without the HW timestamp of the request */
+  if (ts_tx_flags & SOF_TIMESTAMPING_TX_HARDWARE && !NIO_IsServerSocket(sock_fd))
+    monitored_socket = sock_fd;
+
+  /* Check if TX timestamping is disabled on this socket */
+  if (permanent_ts_options || !NIO_IsServerSocket(sock_fd))
+    return;
+
+  message->timestamp.tx_flags = ts_tx_flags;
+}
+
+/* ================================================== */
+
+void
+NIO_Linux_NotifySocketClosing(int sock_fd)
+{
+  resume_socket(sock_fd);
+}
--- a/ntp_io_linux.h
+++ b/ntp_io_linux.h
@@ -0,0 +1,47 @@
+/*
+  chronyd/chronyc - Programs for keeping computer clocks accurate.
+
+ **********************************************************************
+ * Copyright (C) Miroslav Lichvar  2016
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ * 
+ **********************************************************************
+
+  =======================================================================
+
+  This is the header file for the Linux-specific NTP socket I/O bits.
+  */
+
+#ifndef GOT_NTP_IO_LINUX_H
+#define GOT_NTP_IO_LINUX_H
+
+#include "socket.h"
+
+extern void NIO_Linux_Initialise(void);
+
+extern void NIO_Linux_Finalise(void);
+
+extern int NIO_Linux_SetTimestampSocketOptions(int sock_fd, int client_only, int *events);
+
+extern int NIO_Linux_ProcessEvent(int sock_fd, int event);
+
+extern int NIO_Linux_ProcessMessage(SCK_Message *message, NTP_Local_Address *local_addr,
+                                    NTP_Local_Timestamp *local_ts, int event);
+
+extern void NIO_Linux_RequestTxTimestamp(SCK_Message *message, int sock_fd);
+
+extern void NIO_Linux_NotifySocketClosing(int sock_fd);
+
+#endif
--- a/ntp_signd.c
+++ b/ntp_signd.c
@@ -0,0 +1,361 @@
+/*
+  chronyd/chronyc - Programs for keeping computer clocks accurate.
+
+ **********************************************************************
+ * Copyright (C) Miroslav Lichvar  2016
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ * 
+ **********************************************************************
+
+  =======================================================================
+
+  Support for MS-SNTP authentication in Samba (ntp_signd)
+  */
+
+#include "config.h"
+
+#include "sysincl.h"
+
+#include "array.h"
+#include "conf.h"
+#include "logging.h"
+#include "ntp_io.h"
+#include "ntp_signd.h"
+#include "sched.h"
+#include "socket.h"
+#include "util.h"
+
+/* Declarations per samba/source4/librpc/idl/ntp_signd.idl */
+
+#define SIGND_VERSION 0
+
+typedef enum {
+  SIGN_TO_CLIENT = 0,
+  ASK_SERVER_TO_SIGN = 1,
+  CHECK_SERVER_SIGNATURE = 2,
+  SIGNING_SUCCESS = 3,
+  SIGNING_FAILURE = 4,
+} SigndOp;
+
+typedef struct {
+  uint32_t length;
+  uint32_t version;
+  uint32_t op;
+  uint16_t packet_id;
+  uint16_t _pad;
+  uint32_t key_id;
+  NTP_Packet packet_to_sign;
+} SigndRequest;
+
+typedef struct {
+  uint32_t length;
+  uint32_t version;
+  uint32_t op;
+  uint32_t packet_id;
+  NTP_Packet signed_packet;
+} SigndResponse;
+
+typedef struct {
+  NTP_Remote_Address remote_addr;
+  NTP_Local_Address local_addr;
+
+  int sent;
+  int received;
+  int request_length;
+  struct timespec request_ts;
+  SigndRequest request;
+  SigndResponse response;
+} SignInstance;
+
+/* As the communication with ntp_signd is asynchronous, incoming packets are
+   saved in a queue in order to avoid loss when they come in bursts */
+
+#define MAX_QUEUE_LENGTH 16U
+#define NEXT_QUEUE_INDEX(index) (((index) + 1) % MAX_QUEUE_LENGTH)
+#define IS_QUEUE_EMPTY() (queue_head == queue_tail)
+
+/* Fixed-size array of SignInstance */
+static ARR_Instance queue;
+static unsigned int queue_head;
+static unsigned int queue_tail;
+
+#define INVALID_SOCK_FD (-6)
+
+/* Unix domain socket connected to ntp_signd */
+static int sock_fd;
+
+#define MIN_AUTH_DELAY 1.0e-5
+#define MAX_AUTH_DELAY 1.0e-2
+
+/* Average time needed for signing one packet.  This is used to adjust the
+   transmit timestamp in NTP packets.  The timestamp won't be very accurate as
+   the delay is variable, but it should be good enough for MS-SNTP clients. */
+static double auth_delay;
+
+/* Flag indicating if the MS-SNTP authentication is enabled */
+static int enabled;
+
+/* ================================================== */
+
+static void read_write_socket(int sock_fd, int event, void *anything);
+
+/* ================================================== */
+
+static void
+close_socket(void)
+{
+  SCH_RemoveFileHandler(sock_fd);
+  SCK_CloseSocket(sock_fd);
+  sock_fd = INVALID_SOCK_FD;
+
+  /* Empty the queue */
+  queue_head = queue_tail = 0;
+}
+
+/* ================================================== */
+
+static int
+open_socket(void)
+{
+  char path[PATH_MAX];
+
+  if (sock_fd != INVALID_SOCK_FD)
+    return 1;
+
+  if (snprintf(path, sizeof (path), "%s/socket", CNF_GetNtpSigndSocket()) >= sizeof (path)) {
+    DEBUG_LOG("signd socket path too long");
+    return 0;
+  }
+
+  sock_fd = SCK_OpenUnixStreamSocket(path, NULL, 0);
+  if (sock_fd < 0) {
+    sock_fd = INVALID_SOCK_FD;
+    return 0;
+  }
+
+  SCH_AddFileHandler(sock_fd, SCH_FILE_INPUT, read_write_socket, NULL);
+
+  return 1;
+}
+
+/* ================================================== */
+
+static void
+process_response(SignInstance *inst)
+{
+  struct timespec ts;
+  double delay;
+
+  if (ntohs(inst->request.packet_id) != ntohl(inst->response.packet_id)) {
+    DEBUG_LOG("Invalid response ID");
+    return;
+  }
+
+  if (ntohl(inst->response.op) != SIGNING_SUCCESS) {
+    DEBUG_LOG("Signing failed");
+    return;
+  }
+
+  /* Check if the file descriptor is still valid */
+  if (!NIO_IsServerSocket(inst->local_addr.sock_fd)) {
+    DEBUG_LOG("Invalid NTP socket");
+    return;
+  }
+
+  SCH_GetLastEventTime(NULL, NULL, &ts);
+  delay = UTI_DiffTimespecsToDouble(&ts, &inst->request_ts);
+
+  DEBUG_LOG("Signing succeeded (delay %f)", delay);
+
+  /* Send the signed NTP packet */
+  NIO_SendPacket(&inst->response.signed_packet, &inst->remote_addr, &inst->local_addr,
+                 ntohl(inst->response.length) + sizeof (inst->response.length) -
+                 offsetof(SigndResponse, signed_packet), 0);
+
+  /* Update exponential moving average of the authentication delay */
+  delay = CLAMP(MIN_AUTH_DELAY, delay, MAX_AUTH_DELAY);
+  auth_delay += 0.1 * (delay - auth_delay);
+}
+
+/* ================================================== */
+
+static void
+read_write_socket(int sock_fd, int event, void *anything)
+{
+  SignInstance *inst;
+  uint32_t response_length;
+  int s;
+
+  inst = ARR_GetElement(queue, queue_head);
+
+  if (event == SCH_FILE_OUTPUT) {
+    assert(!IS_QUEUE_EMPTY());
+    assert(inst->sent < inst->request_length);
+
+    if (!inst->sent)
+      SCH_GetLastEventTime(NULL, NULL, &inst->request_ts);
+
+    s = SCK_Send(sock_fd, (char *)&inst->request + inst->sent,
+                 inst->request_length - inst->sent, 0);
+
+    if (s < 0) {
+      close_socket();
+      return;
+    }
+
+    inst->sent += s;
+
+    /* Try again later if the request is not complete yet */
+    if (inst->sent < inst->request_length)
+      return;
+
+    /* Disable output and wait for a response */
+    SCH_SetFileHandlerEvent(sock_fd, SCH_FILE_OUTPUT, 0);
+  }
+
+  if (event == SCH_FILE_INPUT) {
+    if (IS_QUEUE_EMPTY()) {
+        DEBUG_LOG("Unexpected signd response");
+        close_socket();
+        return;
+    }
+
+    assert(inst->received < sizeof (inst->response));
+    s = SCK_Receive(sock_fd, (char *)&inst->response + inst->received,
+                    sizeof (inst->response) - inst->received, 0);
+
+    if (s <= 0) {
+      close_socket();
+      return;
+    }
+
+    inst->received += s;
+
+    if (inst->received < sizeof (inst->response.length))
+      return;
+
+    response_length = ntohl(inst->response.length) + sizeof (inst->response.length);
+
+    if (response_length < offsetof(SigndResponse, signed_packet) ||
+        response_length > sizeof (SigndResponse)) {
+      DEBUG_LOG("Invalid response length");
+      close_socket();
+      return;
+    }
+
+    /* Wait for more data if not complete yet */
+    if (inst->received < response_length)
+      return;
+
+    process_response(inst);
+
+    /* Move the head and enable output for the next packet */
+    queue_head = NEXT_QUEUE_INDEX(queue_head);
+    if (!IS_QUEUE_EMPTY())
+      SCH_SetFileHandlerEvent(sock_fd, SCH_FILE_OUTPUT, 1);
+  }
+}
+
+/* ================================================== */
+
+void
+NSD_Initialise()
+{
+  sock_fd = INVALID_SOCK_FD;
+  auth_delay = MIN_AUTH_DELAY;
+  enabled = CNF_GetNtpSigndSocket() && CNF_GetNtpSigndSocket()[0];
+
+  if (!enabled)
+    return;
+
+  queue = ARR_CreateInstance(sizeof (SignInstance));
+  ARR_SetSize(queue, MAX_QUEUE_LENGTH);
+  queue_head = queue_tail = 0;
+
+  LOG(LOGS_INFO, "MS-SNTP authentication enabled");
+}
+
+/* ================================================== */
+
+void
+NSD_Finalise()
+{
+  if (!enabled)
+    return;
+  if (sock_fd != INVALID_SOCK_FD)
+    close_socket();
+  ARR_DestroyInstance(queue);
+}
+
+/* ================================================== */
+
+extern int NSD_GetAuthDelay(uint32_t key_id)
+{
+  return 1.0e9 * auth_delay;
+}
+
+/* ================================================== */
+
+int
+NSD_SignAndSendPacket(uint32_t key_id, NTP_Packet *packet, NTP_PacketInfo *info,
+                      NTP_Remote_Address *remote_addr, NTP_Local_Address *local_addr)
+{
+  SignInstance *inst;
+
+  if (!enabled) {
+    DEBUG_LOG("signd disabled");
+    return 0;
+  }
+
+  if (queue_head == NEXT_QUEUE_INDEX(queue_tail)) {
+    DEBUG_LOG("signd queue full");
+    return 0;
+  }
+
+  if (info->length != NTP_HEADER_LENGTH) {
+    DEBUG_LOG("Invalid packet length");
+    return 0;
+  }
+
+  if (!open_socket())
+    return 0;
+
+  inst = ARR_GetElement(queue, queue_tail);
+  inst->remote_addr = *remote_addr;
+  inst->local_addr = *local_addr;
+  inst->sent = 0;
+  inst->received = 0;
+  inst->request_length = offsetof(SigndRequest, packet_to_sign) + info->length;
+
+  /* The length field doesn't include itself */
+  inst->request.length = htonl(inst->request_length - sizeof (inst->request.length));
+  inst->request.version = htonl(SIGND_VERSION);
+  inst->request.op = htonl(SIGN_TO_CLIENT);
+  inst->request.packet_id = htons(queue_tail);
+  inst->request._pad = 0;
+  inst->request.key_id = htonl(key_id);
+
+  memcpy(&inst->request.packet_to_sign, packet, info->length);
+
+  /* Enable output if there was no pending request */
+  if (IS_QUEUE_EMPTY())
+    SCH_SetFileHandlerEvent(sock_fd, SCH_FILE_OUTPUT, 1);
+
+  queue_tail = NEXT_QUEUE_INDEX(queue_tail);
+
+  DEBUG_LOG("Packet added to signd queue (%u:%u)", queue_head, queue_tail);
+
+  return 1;
+}
--- a/ntp_signd.h
+++ b/ntp_signd.h
@@ -0,0 +1,45 @@
+/*
+  chronyd/chronyc - Programs for keeping computer clocks accurate.
+
+ **********************************************************************
+ * Copyright (C) Miroslav Lichvar  2016
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ * 
+ **********************************************************************
+
+  =======================================================================
+
+  Header for MS-SNTP authentication via Samba (ntp_signd) */
+
+#ifndef GOT_NTP_SIGND_H
+#define GOT_NTP_SIGND_H
+
+#include "addressing.h"
+#include "ntp.h"
+
+/* Initialisation function */
+extern void NSD_Initialise(void);
+
+/* Finalisation function */
+extern void NSD_Finalise(void);
+
+/* Function to get an estimate of delay due to signing */
+extern int NSD_GetAuthDelay(uint32_t key_id);
+
+/* Function to sign an NTP packet and send it */
+extern int NSD_SignAndSendPacket(uint32_t key_id, NTP_Packet *packet, NTP_PacketInfo *info,
+                                 NTP_Remote_Address *remote_addr, NTP_Local_Address *local_addr);
+
+#endif
--- a/ntp_sources.c
+++ b/ntp_sources.c
@@ -34,11 +34,13 @@
 #include "array.h"
 #include "ntp_sources.h"
 #include "ntp_core.h"
+#include "ntp_io.h"
 #include "util.h"
 #include "logging.h"
 #include "local.h"
 #include "memory.h"
 #include "nameserv_async.h"
+#include "privops.h"
 #include "sched.h"

 /* ================================================== */
@@ -47,7 +49,9 @@
   particular sources */
 typedef struct {
  NTP_Remote_Address *remote_addr; /* The address of this source, non-NULL
-                                      means this slot in table is in use */
+                                      means this slot in table is in use
+                                      (an IPADDR_ID address means the address
+                                      is not resolved yet) */
  NCR_Instance data;            /* Data for the protocol engine for this source */
  char *name;                   /* Name of the source, may be NULL */
  int pool;                     /* Number of the pool from which was this source
@@ -66,21 +70,21 @@ static int n_sources;
 /* Flag indicating new sources will be started automatically when added */
 static int auto_start_sources = 0;

-/* Source with unknown address (which may be resolved later) */
+/* Last assigned address ID */
+static uint32_t last_address_id = 0;
+
+/* Source scheduled for name resolving (first resolving or replacement) */
 struct UnresolvedSource {
+  /* Current address of the source (IDADDR_ID is used for a single source
+     with unknown address and IPADDR_UNSPEC for a pool of sources */
+  NTP_Remote_Address address;
+  /* ID of the pool if not a single source */
+  int pool;
+  /* Name to be resolved */
  char *name;
-  int port;
+  /* Flag indicating addresses should be used in a random order */
  int random_order;
-  int replacement;
-  union {
-    struct {
-      NTP_Source_Type type;
-      SourceParameters params;
-      int pool;
-      int max_new_sources;
-    } new_source;
-    NTP_Remote_Address replace_source;
-  };
+  /* Next unresolved source in the list */
  struct UnresolvedSource *next;
 };

@@ -100,9 +104,13 @@ static NSR_SourceResolvingEndHandler resolving_end_handler = NULL;

 /* Pool of sources with the same name */
 struct SourcePool {
-  /* Number of sources added from this pool (ignoring tentative sources) */
+  /* Number of all sources from the pool */
  int sources;
-  /* Maximum number of sources */
+  /* Number of sources with unresolved address */
+  int unresolved_sources;
+  /* Number of non-tentative sources */
+  int confirmed_sources;
+  /* Maximum number of confirmed sources */
  int max_sources;
 };

@@ -112,13 +120,15 @@ static ARR_Instance pools;
 /* ================================================== */
 /* Forward prototypes */

-static void resolve_sources(void *arg);
+static void resolve_sources(void);
 static void rehash_records(void);
 static void clean_source_record(SourceRecord *record);
+static void remove_pool_sources(int pool, int tentative, int unresolved);
+static void remove_unresolved_source(struct UnresolvedSource *us);

 static void
-slew_sources(struct timeval *raw,
-             struct timeval *cooked,
+slew_sources(struct timespec *raw,
+             struct timespec *cooked,
             double dfreq,
             double doffset,
             LCL_ChangeType change_type,
@@ -139,6 +149,14 @@ get_record(unsigned index)

 /* ================================================== */

+static struct SourcePool *
+get_pool(unsigned index)
+{
+  return (struct SourcePool *)ARR_GetElement(pools, index);
+}
+
+/* ================================================== */
+
 void
 NSR_Initialise(void)
 {
@@ -159,11 +177,8 @@ void
 NSR_Finalise(void)
 {
  SourceRecord *record;
-  struct UnresolvedSource *us;
  unsigned int i;

-  ARR_DestroyInstance(pools);
-
  for (i = 0; i < ARR_GetSize(records); i++) {
    record = get_record(i);
    if (record->remote_addr)
@@ -171,13 +186,10 @@ NSR_Finalise(void)
  }

  ARR_DestroyInstance(records);
+  ARR_DestroyInstance(pools);

-  while (unresolved_sources) {
-    us = unresolved_sources;
-    unresolved_sources = us->next;
-    Free(us->name);
-    Free(us);
-  }
+  while (unresolved_sources)
+    remove_unresolved_source(unresolved_sources);

  initialised = 0;
 }
@@ -205,12 +217,14 @@ find_slot(NTP_Remote_Address *remote_addr, int *slot, int *found)
  unsigned short port;

  size = ARR_GetSize(records);
+
+  *slot = 0;
+  *found = 0;
  
  if (remote_addr->ip_addr.family != IPADDR_INET4 &&
-      remote_addr->ip_addr.family != IPADDR_INET6) {
-    *found = *slot = 0;
+      remote_addr->ip_addr.family != IPADDR_INET6 &&
+      remote_addr->ip_addr.family != IPADDR_ID)
    return;
-  }

  hash = UTI_IPToHash(&remote_addr->ip_addr);
  port = remote_addr->port;
@@ -229,8 +243,6 @@ find_slot(NTP_Remote_Address *remote_addr, int *slot, int *found)
      return;
    }
  }
-
-  *found = 0;
 }

 /* ================================================== */
@@ -295,7 +307,8 @@ add_source(NTP_Remote_Address *remote_addr, char *name, NTP_Source_Type type, So
    return NSR_AlreadyInUse;
  } else {
    if (remote_addr->ip_addr.family != IPADDR_INET4 &&
-               remote_addr->ip_addr.family != IPADDR_INET6) {
+        remote_addr->ip_addr.family != IPADDR_INET6 &&
+        remote_addr->ip_addr.family != IPADDR_ID) {
      return NSR_InvalidAF;
    } else {
      n_sources++;
@@ -307,13 +320,19 @@ add_source(NTP_Remote_Address *remote_addr, char *name, NTP_Source_Type type, So

      assert(!found);
      record = get_record(slot);
-      record->data = NCR_GetInstance(remote_addr, type, params);
+      record->data = NCR_CreateInstance(remote_addr, type, params, name);
      record->remote_addr = NCR_GetRemoteAddress(record->data);
      record->name = name ? Strdup(name) : NULL;
      record->pool = pool;
      record->tentative = 1;

-      if (auto_start_sources)
+      if (record->pool != INVALID_POOL) {
+        get_pool(record->pool)->sources++;
+        if (!UTI_IsIPReal(&remote_addr->ip_addr))
+          get_pool(record->pool)->unresolved_sources++;
+      }
+
+      if (auto_start_sources && UTI_IsIPReal(&remote_addr->ip_addr))
        NCR_StartInstance(record->data);

      return NSR_Success;
@@ -324,70 +343,109 @@ add_source(NTP_Remote_Address *remote_addr, char *name, NTP_Source_Type type, So
 /* ================================================== */

 static NSR_Status
-replace_source(NTP_Remote_Address *old_addr, NTP_Remote_Address *new_addr)
+change_source_address(NTP_Remote_Address *old_addr, NTP_Remote_Address *new_addr,
+                      int replacement)
 {
  int slot1, slot2, found;
  SourceRecord *record;
-  struct SourcePool *pool;
+  LOG_Severity severity;
+  char *name;

  find_slot(old_addr, &slot1, &found);
  if (!found)
    return NSR_NoSuchSource;

+  /* Make sure there is no other source using the new address (with the same
+     or different port), but allow a source to have its port changed */
  find_slot(new_addr, &slot2, &found);
-  if (found)
+  if (found == 2 || (found != 0 && slot1 != slot2))
    return NSR_AlreadyInUse;

  record = get_record(slot1);
-  NCR_ChangeRemoteAddress(record->data, new_addr);
+  NCR_ChangeRemoteAddress(record->data, new_addr, !replacement);
  record->remote_addr = NCR_GetRemoteAddress(record->data);
+  if (!UTI_IsIPReal(&old_addr->ip_addr) && UTI_IsIPReal(&new_addr->ip_addr)) {
+    if (auto_start_sources)
+      NCR_StartInstance(record->data);
+    if (record->pool != INVALID_POOL)
+      get_pool(record->pool)->unresolved_sources--;
+  }

  if (!record->tentative) {
    record->tentative = 1;

-    if (record->pool != INVALID_POOL) {
-      pool = ARR_GetElement(pools, record->pool);
-      pool->sources--;
-    }
+    if (record->pool != INVALID_POOL)
+      get_pool(record->pool)->confirmed_sources--;
  }

-  /* The hash table must be rebuilt for the new address */
-  rehash_records();
+  name = record->name;
+  severity = UTI_IsIPReal(&old_addr->ip_addr) ? LOGS_INFO : LOGS_DEBUG;

-  LOG(LOGS_INFO, LOGF_NtpSources, "Source %s replaced with %s",
-      UTI_IPToString(&old_addr->ip_addr),
-      UTI_IPToString(&new_addr->ip_addr));
+  if (slot1 != slot2) {
+    /* The hash table must be rebuilt for the changed address */
+    rehash_records();
+
+    LOG(severity, "Source %s %s %s (%s)", UTI_IPToString(&old_addr->ip_addr),
+        replacement ? "replaced with" : "changed to",
+        UTI_IPToString(&new_addr->ip_addr), name ? name : "");
+  } else {
+    LOG(severity, "Source %s (%s) changed port to %d",
+        UTI_IPToString(&new_addr->ip_addr), name ? name : "", new_addr->port);
+  }

  return NSR_Success;
 }

 /* ================================================== */

+static int
+replace_source_connectable(NTP_Remote_Address *old_addr, NTP_Remote_Address *new_addr)
+{
+  if (!NIO_IsServerConnectable(new_addr)) {
+    DEBUG_LOG("%s not connectable", UTI_IPToString(&new_addr->ip_addr));
+    return 0;
+  }
+
+  if (change_source_address(old_addr, new_addr, 1) == NSR_AlreadyInUse)
+    return 0;
+
+  return 1;
+}
+
+/* ================================================== */
+
 static void
 process_resolved_name(struct UnresolvedSource *us, IPAddr *ip_addrs, int n_addrs)
 {
-  NTP_Remote_Address address;
-  int i, added;
+  NTP_Remote_Address old_addr, new_addr;
+  SourceRecord *record;
  unsigned short first = 0;
+  int i, j;

  if (us->random_order)
    UTI_GetRandomBytes(&first, sizeof (first));

-  for (i = added = 0; i < n_addrs; i++) {
-    address.ip_addr = ip_addrs[((unsigned int)i + first) % n_addrs];
-    address.port = us->port;
+  for (i = 0; i < n_addrs; i++) {
+    new_addr.ip_addr = ip_addrs[((unsigned int)i + first) % n_addrs];

-    DEBUG_LOG(LOGF_NtpSources, "(%d) %s", i + 1, UTI_IPToString(&address.ip_addr));
+    DEBUG_LOG("(%d) %s", i + 1, UTI_IPToString(&new_addr.ip_addr));

-    if (us->replacement) {
-      if (replace_source(&us->replace_source, &address) != NSR_AlreadyInUse)
-        break;
+    if (us->pool != INVALID_POOL) {
+      /* In the pool resolving mode, try to replace all sources from
+         the pool which don't have a real address yet */
+      for (j = 0; j < ARR_GetSize(records); j++) {
+        record = get_record(j);
+        if (!record->remote_addr || record->pool != us->pool ||
+            UTI_IsIPReal(&record->remote_addr->ip_addr))
+          continue;
+        old_addr = *record->remote_addr;
+        new_addr.port = old_addr.port;
+        if (replace_source_connectable(&old_addr, &new_addr))
+          break;
+      }
    } else {
-      if (add_source(&address, us->name, us->new_source.type, &us->new_source.params,
-                     us->new_source.pool) == NSR_Success)
-        added++;
-
-      if (added >= us->new_source.max_new_sources)
+      new_addr.port = us->address.port;
+      if (replace_source_connectable(&us->address, &new_addr))
        break;
    }
  }
@@ -395,16 +453,43 @@ process_resolved_name(struct UnresolvedSource *us, IPAddr *ip_addrs, int n_addrs

 /* ================================================== */

+static int
+is_resolved(struct UnresolvedSource *us)
+{
+  int slot, found;
+
+  if (us->pool != INVALID_POOL) {
+    return get_pool(us->pool)->unresolved_sources <= 0;
+  } else {
+    /* If the address is no longer present, it was removed or replaced
+       (i.e. resolved) */
+    find_slot(&us->address, &slot, &found);
+    return !found;
+  }
+}
+
+/* ================================================== */
+
+static void
+resolve_sources_timeout(void *arg)
+{
+  resolving_id = 0;
+  resolve_sources();
+}
+
+/* ================================================== */
+
 static void
 name_resolve_handler(DNS_Status status, int n_addrs, IPAddr *ip_addrs, void *anything)
 {
-  struct UnresolvedSource *us, **i, *next;
+  struct UnresolvedSource *us, *next;

  us = (struct UnresolvedSource *)anything;

  assert(us == resolving_source);
+  assert(resolving_id == 0);

-  DEBUG_LOG(LOGF_NtpSources, "%s resolved to %d addrs", us->name, n_addrs);
+  DEBUG_LOG("%s resolved to %d addrs", us->name, n_addrs);

  switch (status) {
    case DNS_TryAgain:
@@ -413,7 +498,7 @@ name_resolve_handler(DNS_Status status, int n_addrs, IPAddr *ip_addrs, void *any
      process_resolved_name(us, ip_addrs, n_addrs);
      break;
    case DNS_Failure:
-      LOG(LOGS_WARN, LOGF_NtpSources, "Invalid host %s", us->name);
+      LOG(LOGS_WARN, "Invalid host %s", us->name);
      break;
    default:
      assert(0);
@@ -421,35 +506,25 @@ name_resolve_handler(DNS_Status status, int n_addrs, IPAddr *ip_addrs, void *any

  next = us->next;

-  /* Remove the source from the list on success or failure, replacements
-     are removed on any status */
-  if (us->replacement || status != DNS_TryAgain) {
-    for (i = &unresolved_sources; *i; i = &(*i)->next) {
-      if (*i == us) {
-        *i = us->next;
-        Free(us->name);
-        Free(us);
-        break;
-      }
-    }
-  }
+  /* Don't repeat the resolving if it (permanently) failed, it was a
+     replacement of a real address, or all addresses are already resolved */
+  if (status == DNS_Failure || UTI_IsIPReal(&us->address.ip_addr) || is_resolved(us))
+    remove_unresolved_source(us);

  resolving_source = next;

  if (next) {
    /* Continue with the next source in the list */
-    DEBUG_LOG(LOGF_NtpSources, "resolving %s", next->name);
+    DEBUG_LOG("resolving %s", next->name);
    DNS_Name2IPAddressAsync(next->name, name_resolve_handler, next);
  } else {
    /* This was the last source in the list. If some sources couldn't
       be resolved, try again in exponentially increasing interval. */
    if (unresolved_sources) {
-      if (resolving_interval < MIN_RESOLVE_INTERVAL)
-        resolving_interval = MIN_RESOLVE_INTERVAL;
-      else if (resolving_interval < MAX_RESOLVE_INTERVAL)
-        resolving_interval++;
-      resolving_id = SCH_AddTimeoutByDelay(RESOLVE_INTERVAL_UNIT *
-          (1 << resolving_interval), resolve_sources, NULL);
+      resolving_interval = CLAMP(MIN_RESOLVE_INTERVAL, resolving_interval + 1,
+                                 MAX_RESOLVE_INTERVAL);
+      resolving_id = SCH_AddTimeoutByDelay(RESOLVE_INTERVAL_UNIT * (1 << resolving_interval),
+                                           resolve_sources_timeout, NULL);
    } else {
      resolving_interval = 0;
    }
@@ -463,20 +538,30 @@ name_resolve_handler(DNS_Status status, int n_addrs, IPAddr *ip_addrs, void *any
 /* ================================================== */

 static void
-resolve_sources(void *arg)
+resolve_sources(void)
 {
-  struct UnresolvedSource *us;
+  struct UnresolvedSource *us, *next, *i;

  assert(!resolving_source);

-  DNS_Reload();
+  /* Remove sources that don't need to be resolved anymore */
+  for (i = unresolved_sources; i; i = next) {
+    next = i->next;
+    if (is_resolved(i))
+      remove_unresolved_source(i);
+  }
+
+  if (!unresolved_sources)
+    return;
+
+  PRV_ReloadDNS();

  /* Start with the first source in the list, name_resolve_handler
     will iterate over the rest */
  us = unresolved_sources;

  resolving_source = us;
-  DEBUG_LOG(LOGF_NtpSources, "resolving %s", us->name);
+  DEBUG_LOG("resolving %s", us->name);
  DNS_Name2IPAddressAsync(us->name, name_resolve_handler, us);
 }

@@ -495,6 +580,23 @@ append_unresolved_source(struct UnresolvedSource *us)

 /* ================================================== */

+static void
+remove_unresolved_source(struct UnresolvedSource *us)
+{
+  struct UnresolvedSource **i;
+
+  for (i = &unresolved_sources; *i; i = &(*i)->next) {
+    if (*i == us) {
+      *i = us->next;
+      Free(us->name);
+      Free(us);
+      break;
+    }
+  }
+}
+
+/* ================================================== */
+
 NSR_Status
 NSR_AddSource(NTP_Remote_Address *remote_addr, NTP_Source_Type type, SourceParameters *params)
 {
@@ -503,41 +605,60 @@ NSR_AddSource(NTP_Remote_Address *remote_addr, NTP_Source_Type type, SourceParam

 /* ================================================== */

-void
+NSR_Status
 NSR_AddSourceByName(char *name, int port, int pool, NTP_Source_Type type, SourceParameters *params)
 {
  struct UnresolvedSource *us;
  struct SourcePool *sp;
  NTP_Remote_Address remote_addr;
+  int i, new_sources;

  /* If the name is an IP address, don't bother with full resolving now
     or later when trying to replace the source */
  if (UTI_StringToIP(name, &remote_addr.ip_addr)) {
    remote_addr.port = port;
-    NSR_AddSource(&remote_addr, type, params);
-    return;
+    return NSR_AddSource(&remote_addr, type, params);
+  }
+
+  /* Make sure the name is at least printable and has no spaces */
+  for (i = 0; name[i] != '\0'; i++) {
+    if (!isgraph(name[i]))
+      return NSR_InvalidName;
  }

  us = MallocNew(struct UnresolvedSource);
  us->name = Strdup(name);
-  us->port = port;
  us->random_order = 0;
-  us->replacement = 0;
-  us->new_source.type = type;
-  us->new_source.params = *params;
+
+  remote_addr.ip_addr.family = IPADDR_ID;
+  remote_addr.ip_addr.addr.id = ++last_address_id;
+  remote_addr.port = port;

  if (!pool) {
-    us->new_source.pool = INVALID_POOL;
-    us->new_source.max_new_sources = 1;
+    us->pool = INVALID_POOL;
+    us->address = remote_addr;
+    new_sources = 1;
  } else {
    sp = (struct SourcePool *)ARR_GetNewElement(pools);
    sp->sources = 0;
-    sp->max_sources = params->max_sources;
-    us->new_source.pool = ARR_GetSize(pools) - 1;
-    us->new_source.max_new_sources = MAX_POOL_SOURCES;
+    sp->unresolved_sources = 0;
+    sp->confirmed_sources = 0;
+    sp->max_sources = CLAMP(1, params->max_sources, MAX_POOL_SOURCES);
+    us->pool = ARR_GetSize(pools) - 1;
+    us->address.ip_addr.family = IPADDR_UNSPEC;
+    new_sources = MIN(2 * sp->max_sources, MAX_POOL_SOURCES);
  }

  append_unresolved_source(us);
+
+  for (i = 0; i < new_sources; i++) {
+    if (i > 0)
+      remote_addr.ip_addr.addr.id = ++last_address_id;
+    if (add_source(&remote_addr, name, type, params, us->pool) != NSR_Success)
+      return NSR_TooManySources;
+  }
+
+  return NSR_UnresolvedName;
 }

 /* ================================================== */
@@ -557,11 +678,12 @@ NSR_ResolveSources(void)
  if (unresolved_sources) {
    /* Make sure no resolving is currently running */
    if (!resolving_source) {
-      if (resolving_interval) {
+      if (resolving_id != 0) {
        SCH_RemoveTimeout(resolving_id);
+        resolving_id = 0;
        resolving_interval--;
      }
-      resolve_sources(NULL);
+      resolve_sources();
    }
  } else {
    /* No unresolved sources, we are done */
@@ -574,10 +696,12 @@ NSR_ResolveSources(void)

 void NSR_StartSources(void)
 {
+  NTP_Remote_Address *addr;
  unsigned int i;

  for (i = 0; i < ARR_GetSize(records); i++) {
-    if (!get_record(i)->remote_addr)
+    addr = get_record(i)->remote_addr;
+    if (!addr || !UTI_IsIPReal(&addr->ip_addr))
      continue;
    NCR_StartInstance(get_record(i)->data);
  }
@@ -596,6 +720,19 @@ static void
 clean_source_record(SourceRecord *record)
 {
  assert(record->remote_addr);
+
+  if (record->pool != INVALID_POOL) {
+    struct SourcePool *pool = get_pool(record->pool);
+
+    pool->sources--;
+    if (!UTI_IsIPReal(&record->remote_addr->ip_addr))
+      pool->unresolved_sources--;
+    if (!record->tentative)
+      pool->confirmed_sources--;
+    if (pool->max_sources > pool->sources)
+      pool->max_sources = pool->sources;
+  }
+
  record->remote_addr = NULL;
  NCR_DestroyInstance(record->data);
  if (record->name)
@@ -657,19 +794,17 @@ resolve_source_replacement(SourceRecord *record)
 {
  struct UnresolvedSource *us;

-  DEBUG_LOG(LOGF_NtpSources, "trying to replace %s",
-            UTI_IPToString(&record->remote_addr->ip_addr));
+  DEBUG_LOG("trying to replace %s", UTI_IPToString(&record->remote_addr->ip_addr));

  us = MallocNew(struct UnresolvedSource);
  us->name = Strdup(record->name);
-  us->port = record->remote_addr->port;
  /* If there never was a valid reply from this source (e.g. it was a bad
     replacement), ignore the order of addresses from the resolver to not get
     stuck to a pair of addresses if the order doesn't change, or a group of
     IPv4/IPv6 addresses if the resolver prefers inaccessible IP family */
  us->random_order = record->tentative;
-  us->replacement = 1;
-  us->replace_source = *record->remote_addr;
+  us->pool = INVALID_POOL;
+  us->address = *record->remote_addr;

  append_unresolved_source(us);
  NSR_ResolveSources();
@@ -680,8 +815,8 @@ resolve_source_replacement(SourceRecord *record)
 void
 NSR_HandleBadSource(IPAddr *address)
 {
-  static struct timeval last_replacement;
-  struct timeval now;
+  static struct timespec last_replacement;
+  struct timespec now;
  NTP_Remote_Address remote_addr;
  SourceRecord *record;
  int slot, found;
@@ -702,9 +837,9 @@ NSR_HandleBadSource(IPAddr *address)

  /* Don't resolve names too frequently */
  SCH_GetLastEventTime(NULL, NULL, &now);
-  UTI_DiffTimevalsToDouble(&diff, &now, &last_replacement);
+  diff = UTI_DiffTimespecsToDouble(&now, &last_replacement);
  if (fabs(diff) < RESOLVE_INTERVAL_UNIT * (1 << MIN_REPLACEMENT_INTERVAL)) {
-    DEBUG_LOG(LOGF_NtpSources, "replacement postponed");
+    DEBUG_LOG("replacement postponed");
    return;
  }
  last_replacement = now;
@@ -731,7 +866,18 @@ NSR_RefreshAddresses(void)

 /* ================================================== */

-static void remove_tentative_pool_sources(int pool)
+NSR_Status
+NSR_UpdateSourceNtpAddress(NTP_Remote_Address *old_addr, NTP_Remote_Address *new_addr)
+{
+  if (new_addr->ip_addr.family == IPADDR_UNSPEC)
+    return NSR_InvalidAF;
+
+  return change_source_address(old_addr, new_addr, 0);
+}
+
+/* ================================================== */
+
+static void remove_pool_sources(int pool, int tentative, int unresolved)
 {
  SourceRecord *record;
  unsigned int i, removed;
@@ -739,10 +885,14 @@ static void remove_tentative_pool_sources(int pool)
  for (i = removed = 0; i < ARR_GetSize(records); i++) {
    record = get_record(i);

-    if (!record->remote_addr || record->pool != pool || !record->tentative)
+    if (!record->remote_addr || record->pool != pool)
      continue;

-    DEBUG_LOG(LOGF_NtpSources, "removing tentative source %s",
+    if ((tentative && !record->tentative) ||
+        (unresolved && UTI_IsIPReal(&record->remote_addr->ip_addr)))
+      continue;
+
+    DEBUG_LOG("removing %ssource %s", tentative ? "tentative " : "",
              UTI_IPToString(&record->remote_addr->ip_addr));

    clean_source_record(record);
@@ -773,10 +923,34 @@ NSR_GetLocalRefid(IPAddr *address)

 /* ================================================== */

+char *
+NSR_GetName(IPAddr *address)
+{
+  NTP_Remote_Address remote_addr;
+  int slot, found;
+  SourceRecord *record;
+
+  remote_addr.ip_addr = *address;
+  remote_addr.port = 0;
+
+  find_slot(&remote_addr, &slot, &found);
+  if (!found)
+    return NULL;
+
+  record = get_record(slot);
+  if (record->name)
+    return record->name;
+
+  return UTI_IPToString(&record->remote_addr->ip_addr); 
+}
+
+/* ================================================== */
+
 /* This routine is called by ntp_io when a new packet arrives off the network,
   possibly with an authentication tail */
 void
-NSR_ProcessReceive(NTP_Packet *message, struct timeval *now, double now_err, NTP_Remote_Address *remote_addr, NTP_Local_Address *local_addr, int length)
+NSR_ProcessRx(NTP_Remote_Address *remote_addr, NTP_Local_Address *local_addr,
+              NTP_Local_Timestamp *rx_ts, NTP_Packet *message, int length)
 {
  SourceRecord *record;
  struct SourcePool *pool;
@@ -788,36 +962,54 @@ NSR_ProcessReceive(NTP_Packet *message, struct timeval *now, double now_err, NTP
  if (found == 2) { /* Must match IP address AND port number */
    record = get_record(slot);

-    if (!NCR_ProcessKnown(message, now, now_err, record->data, local_addr, length))
+    if (!NCR_ProcessRxKnown(record->data, local_addr, rx_ts, message, length))
      return;

    if (record->tentative) {
-      /* This was the first valid reply from the source */
+      /* This was the first good reply from the source */
      record->tentative = 0;

      if (record->pool != INVALID_POOL) {
-        pool = ARR_GetElement(pools, record->pool);
-        pool->sources++;
+        pool = get_pool(record->pool);
+        pool->confirmed_sources++;

-        DEBUG_LOG(LOGF_NtpSources, "pool %s has %d confirmed sources",
-                  record->name, pool->sources);
+        DEBUG_LOG("pool %s has %d confirmed sources", record->name, pool->confirmed_sources);

        /* If the number of sources from the pool reached the configured
           maximum, remove the remaining tentative sources */
-        if (pool->sources >= pool->max_sources)
-          remove_tentative_pool_sources(record->pool);
+        if (pool->confirmed_sources >= pool->max_sources)
+          remove_pool_sources(record->pool, 1, 0);
      }
    }
  } else {
-    NCR_ProcessUnknown(message, now, now_err, remote_addr, local_addr, length);
+    NCR_ProcessRxUnknown(remote_addr, local_addr, rx_ts, message, length);
+  }
+}
+
+/* ================================================== */
+
+void
+NSR_ProcessTx(NTP_Remote_Address *remote_addr, NTP_Local_Address *local_addr,
+              NTP_Local_Timestamp *tx_ts, NTP_Packet *message, int length)
+{
+  SourceRecord *record;
+  int slot, found;
+
+  find_slot(remote_addr, &slot, &found);
+
+  if (found == 2) { /* Must match IP address AND port number */
+    record = get_record(slot);
+    NCR_ProcessTxKnown(record->data, local_addr, tx_ts, message, length);
+  } else {
+    NCR_ProcessTxUnknown(remote_addr, local_addr, tx_ts, message, length);
  }
 }

 /* ================================================== */

 static void
-slew_sources(struct timeval *raw,
-             struct timeval *cooked,
+slew_sources(struct timespec *raw,
+             struct timespec *cooked,
             double dfreq,
             double doffset,
             LCL_ChangeType change_type,
@@ -831,6 +1023,7 @@ slew_sources(struct timeval *raw,
    if (record->remote_addr) {
      if (change_type == LCL_ChangeUnknownStep) {
        NCR_ResetInstance(record->data);
+        NCR_ResetPoll(record->data);
      } else {
        NCR_SlewTimes(record->data, cooked, dfreq, doffset);
      }
@@ -841,80 +1034,37 @@ slew_sources(struct timeval *raw,
 /* ================================================== */

 int
-NSR_TakeSourcesOnline(IPAddr *mask, IPAddr *address)
-{
-  SourceRecord *record;
-  unsigned int i;
-  int any;
-
-  NSR_ResolveSources();
-
-  any = 0;
-  for (i = 0; i < ARR_GetSize(records); i++) {
-    record = get_record(i);
-    if (record->remote_addr) {
-      if (address->family == IPADDR_UNSPEC ||
-          !UTI_CompareIPs(&record->remote_addr->ip_addr, address, mask)) {
-        any = 1;
-        NCR_TakeSourceOnline(record->data);
-      }
-    }
-  }
-
-  if (address->family == IPADDR_UNSPEC) {
-    struct UnresolvedSource *us;
-
-    for (us = unresolved_sources; us; us = us->next) {
-      if (us->replacement)
-        continue;
-      any = 1;
-      us->new_source.params.online = 1;
-    }
-  }
-
-  return any;
-}
-
-/* ================================================== */
-
-int
-NSR_TakeSourcesOffline(IPAddr *mask, IPAddr *address)
+NSR_SetConnectivity(IPAddr *mask, IPAddr *address, SRC_Connectivity connectivity)
 {
  SourceRecord *record, *syncpeer;
  unsigned int i, any;

+  if (connectivity != SRC_OFFLINE)
+    NSR_ResolveSources();
+
  any = 0;
  syncpeer = NULL;
  for (i = 0; i < ARR_GetSize(records); i++) {
    record = get_record(i);
    if (record->remote_addr) {
-      if (address->family == IPADDR_UNSPEC ||
+      /* Ignore SRC_MAYBE_ONLINE connectivity change for unspecified unresolved
+         sources as they would always end up in the offline state */
+      if ((address->family == IPADDR_UNSPEC &&
+           (connectivity != SRC_MAYBE_ONLINE || UTI_IsIPReal(&record->remote_addr->ip_addr))) ||
          !UTI_CompareIPs(&record->remote_addr->ip_addr, address, mask)) {
        any = 1;
        if (NCR_IsSyncPeer(record->data)) {
          syncpeer = record;
          continue;
        }
-        NCR_TakeSourceOffline(record->data);
+        NCR_SetConnectivity(record->data, connectivity);
      }
    }
  }

-  /* Take sync peer offline as last to avoid reference switching */
-  if (syncpeer) {
-    NCR_TakeSourceOffline(syncpeer->data);
-  }
-
-  if (address->family == IPADDR_UNSPEC) {
-    struct UnresolvedSource *us;
-
-    for (us = unresolved_sources; us; us = us->next) {
-      if (us->replacement)
-        continue;
-      any = 1;
-      us->new_source.params.online = 0;
-    }
-  }
+  /* Set the sync peer last to avoid unnecessary reference switching */
+  if (syncpeer)
+    NCR_SetConnectivity(syncpeer->data, connectivity);

  return any;
 }
@@ -1083,7 +1233,7 @@ NSR_InitiateSampleBurst(int n_good_samples, int n_total_samples,
   identify the source record. */

 void
-NSR_ReportSource(RPT_SourceReport *report, struct timeval *now)
+NSR_ReportSource(RPT_SourceReport *report, struct timespec *now)
 {
  NTP_Remote_Address rem_addr;
  int slot, found;
@@ -1099,6 +1249,26 @@ NSR_ReportSource(RPT_SourceReport *report, struct timeval *now)
  }
 }

+/* ================================================== */
+/* The ip address is assumed to be completed on input, that is how we
+   identify the source record. */
+
+int
+NSR_GetNTPReport(RPT_NTPReport *report)
+{
+  NTP_Remote_Address rem_addr;
+  int slot, found;
+
+  rem_addr.ip_addr = report->remote_addr;
+  rem_addr.port = 0;
+  find_slot(&rem_addr, &slot, &found);
+  if (!found)
+    return 0;
+
+  NCR_GetNTPReport(get_record(slot)->data, report);
+  return 1;
+}
+
 /* ================================================== */

 void
@@ -1106,26 +1276,25 @@ NSR_GetActivityReport(RPT_ActivityReport *report)
 {
  SourceRecord *record;
  unsigned int i;
-  struct UnresolvedSource *us;

  report->online = 0;
  report->offline = 0;
  report->burst_online = 0;
  report->burst_offline = 0;
+  report->unresolved = 0;

  for (i = 0; i < ARR_GetSize(records); i++) {
    record = get_record(i);
-    if (record->remote_addr) {
+    if (!record->remote_addr)
+      continue;
+
+    if (!UTI_IsIPReal(&record->remote_addr->ip_addr)) {
+      report->unresolved++;
+    } else {
      NCR_IncrementActivityCounters(record->data, &report->online, &report->offline,
                                    &report->burst_online, &report->burst_offline);
    }
  }
-
-  report->unresolved = 0;
-
-  for (us = unresolved_sources; us; us = us->next) {
-    report->unresolved++;
-  }
 }


--- a/ntp_sources.h
+++ b/ntp_sources.h
@@ -44,7 +44,9 @@ typedef enum {
  NSR_NoSuchSource, /* Remove - attempt to remove a source that is not known */
  NSR_AlreadyInUse, /* AddSource - attempt to add a source that is already known */ 
  NSR_TooManySources, /* AddSource - too many sources already present */
-  NSR_InvalidAF /* AddSource - attempt to add a source with invalid address family */
+  NSR_InvalidAF, /* AddSource - attempt to add a source with invalid address family */
+  NSR_InvalidName, /* AddSourceByName - attempt to add a source with invalid name */
+  NSR_UnresolvedName, /* AddSourceByName - name will be resolved later */
 } NSR_Status;

 /* Procedure to add a new server or peer source. */
@@ -52,8 +54,10 @@ extern NSR_Status NSR_AddSource(NTP_Remote_Address *remote_addr, NTP_Source_Type

 /* Procedure to add a new server, peer source, or pool of servers specified by
   name instead of address.  The name is resolved in exponentially increasing
-   intervals until it succeeds or fails with a non-temporary error. */
-extern void NSR_AddSourceByName(char *name, int port, int pool, NTP_Source_Type type, SourceParameters *params);
+   intervals until it succeeds or fails with a non-temporary error.  If the
+   name is an address, it is equivalent to NSR_AddSource(). */
+extern NSR_Status NSR_AddSourceByName(char *name, int port, int pool, NTP_Source_Type type,
+                                      SourceParameters *params);

 /* Function type for handlers to be called back when an attempt
 * (possibly unsuccessful) to resolve unresolved sources ends */
@@ -83,11 +87,25 @@ extern void NSR_HandleBadSource(IPAddr *address);
 /* Procedure to resolve all names again */
 extern void NSR_RefreshAddresses(void);

+/* Procedure to update the address of a source */
+extern NSR_Status NSR_UpdateSourceNtpAddress(NTP_Remote_Address *old_addr,
+                                             NTP_Remote_Address *new_addr);
+
 /* Procedure to get local reference ID corresponding to a source */
 extern uint32_t NSR_GetLocalRefid(IPAddr *address);

+/* Procedure to get the name of a source.  If the source doesn't have a name,
+   it returns a temporary string containing formatted address. */
+extern char *NSR_GetName(IPAddr *address);
+
 /* This routine is called by ntp_io when a new packet arrives off the network */
-extern void NSR_ProcessReceive(NTP_Packet *message, struct timeval *now, double now_err, NTP_Remote_Address *remote_addr, NTP_Local_Address *local_addr, int length);
+extern void NSR_ProcessRx(NTP_Remote_Address *remote_addr, NTP_Local_Address *local_addr,
+                          NTP_Local_Timestamp *rx_ts, NTP_Packet *message, int length);
+
+/* This routine is called by ntp_io when a packet was sent to the network and
+   an accurate transmit timestamp was captured */
+extern void NSR_ProcessTx(NTP_Remote_Address *remote_addr, NTP_Local_Address *local_addr,
+                          NTP_Local_Timestamp *tx_ts, NTP_Packet *message, int length);

 /* Initialisation function */
 extern void NSR_Initialise(void);
@@ -96,14 +114,9 @@ extern void NSR_Initialise(void);
 extern void NSR_Finalise(void);

 /* This routine is used to indicate that sources whose IP addresses
-   match a particular subnet should be set online again.  Returns a
-   flag indicating whether any hosts matched the address */
-extern int NSR_TakeSourcesOnline(IPAddr *mask, IPAddr *address);
-
-/* This routine is used to indicate that sources whose IP addresses
-   match a particular subnet should be set offline.  Returns a flag
-   indicating whether any hosts matched the address */
-extern int NSR_TakeSourcesOffline(IPAddr *mask, IPAddr *address);
+   match a particular subnet should be set online or offline.  It returns
+   a flag indicating whether any hosts matched the address. */
+extern int NSR_SetConnectivity(IPAddr *mask, IPAddr *address, SRC_Connectivity connectivity);

 extern int NSR_ModifyMinpoll(IPAddr *address, int new_minpoll);

@@ -121,7 +134,9 @@ extern int NSR_ModifyPolltarget(IPAddr *address, int new_poll_target);

 extern int NSR_InitiateSampleBurst(int n_good_samples, int n_total_samples, IPAddr *mask, IPAddr *address);

-extern void NSR_ReportSource(RPT_SourceReport *report, struct timeval *now);
+extern void NSR_ReportSource(RPT_SourceReport *report, struct timespec *now);
+
+extern int NSR_GetNTPReport(RPT_NTPReport *report);

 extern void NSR_GetActivityReport(RPT_ActivityReport *report);

--- a/nts_ke.h
+++ b/nts_ke.h
@@ -0,0 +1,69 @@
+/*
+  chronyd/chronyc - Programs for keeping computer clocks accurate.
+
+ **********************************************************************
+ * Copyright (C) Miroslav Lichvar  2020
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ * 
+ **********************************************************************
+
+  =======================================================================
+
+  Header file for the NTS Key Establishment protocol
+  */
+
+#ifndef GOT_NTS_KE_H
+#define GOT_NTS_KE_H
+
+#include "siv.h"
+
+#define NKE_RECORD_CRITICAL_BIT         (1U << 15)
+#define NKE_RECORD_END_OF_MESSAGE       0
+#define NKE_RECORD_NEXT_PROTOCOL        1
+#define NKE_RECORD_ERROR                2
+#define NKE_RECORD_WARNING              3
+#define NKE_RECORD_AEAD_ALGORITHM       4
+#define NKE_RECORD_COOKIE               5
+#define NKE_RECORD_NTPV4_SERVER_NEGOTIATION 6
+#define NKE_RECORD_NTPV4_PORT_NEGOTIATION 7
+
+#define NKE_NEXT_PROTOCOL_NTPV4         0
+
+#define NKE_ERROR_UNRECOGNIZED_CRITICAL_RECORD 0
+#define NKE_ERROR_BAD_REQUEST           1
+#define NKE_ERROR_INTERNAL_SERVER_ERROR 2
+
+#define NKE_ALPN_NAME                   "ntske/1"
+#define NKE_EXPORTER_LABEL              "EXPORTER-network-time-security/1"
+#define NKE_EXPORTER_CONTEXT_C2S        "\x0\x0\x0\xf\x0"
+#define NKE_EXPORTER_CONTEXT_S2C        "\x0\x0\x0\xf\x1"
+
+#define NKE_MAX_MESSAGE_LENGTH          16384
+#define NKE_MAX_RECORD_BODY_LENGTH      256
+#define NKE_MAX_COOKIE_LENGTH           256
+#define NKE_MAX_COOKIES                 8
+#define NKE_MAX_KEY_LENGTH SIV_MAX_KEY_LENGTH
+
+typedef struct {
+  int length;
+  unsigned char key[NKE_MAX_KEY_LENGTH];
+} NKE_Key;
+
+typedef struct {
+  int length;
+  unsigned char cookie[NKE_MAX_COOKIE_LENGTH];
+} NKE_Cookie;
+
+#endif
--- a/nts_ke_client.c
+++ b/nts_ke_client.c
@@ -0,0 +1,389 @@
+/*
+  chronyd/chronyc - Programs for keeping computer clocks accurate.
+
+ **********************************************************************
+ * Copyright (C) Miroslav Lichvar  2020
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ * 
+ **********************************************************************
+
+  =======================================================================
+
+  NTS-KE client
+  */
+
+#include "config.h"
+
+#include "sysincl.h"
+
+#include "nts_ke_client.h"
+
+#include "conf.h"
+#include "logging.h"
+#include "memory.h"
+#include "nameserv_async.h"
+#include "nts_ke_session.h"
+#include "siv.h"
+#include "socket.h"
+#include "util.h"
+
+#define CLIENT_TIMEOUT 16.0
+
+struct NKC_Instance_Record {
+  char *name;
+  IPSockAddr address;
+  NKSN_Instance session;
+  int destroying;
+  int got_response;
+  int resolving_name;
+
+  SIV_Algorithm siv_algorithm;
+  NKE_Key c2s, s2c;
+  NKE_Cookie cookies[NKE_MAX_COOKIES];
+  int num_cookies;
+  char server_name[NKE_MAX_RECORD_BODY_LENGTH + 1];
+  IPSockAddr ntp_address;
+};
+
+/* ================================================== */
+
+static void *client_credentials;
+
+/* ================================================== */
+
+static void
+name_resolve_handler(DNS_Status status, int n_addrs, IPAddr *ip_addrs, void *arg)
+{
+  NKC_Instance inst = arg;
+  int i;
+
+  inst->resolving_name = 0;
+
+  if (inst->destroying) {
+    NKC_DestroyInstance(inst);
+    return;
+  }
+
+  if (status != DNS_Success || n_addrs < 1) {
+    LOG(LOGS_ERR, "Could not resolve NTP server %s from %s", inst->server_name, inst->name);
+    /* Force restart */
+    inst->got_response = 0;
+    return;
+  }
+
+  inst->ntp_address.ip_addr = ip_addrs[0];
+
+  /* Prefer an address of the same family as NTS-KE */
+  for (i = 0; i < n_addrs; i++) {
+    DEBUG_LOG("%s resolved to %s", inst->server_name, UTI_IPToString(&ip_addrs[i]));
+    if (ip_addrs[i].family == inst->address.ip_addr.family) {
+      inst->ntp_address.ip_addr = ip_addrs[i];
+      break;
+    }
+  }
+}
+
+/* ================================================== */
+
+static int
+prepare_request(NKC_Instance inst)
+{
+  NKSN_Instance session = inst->session;
+  uint16_t datum;
+
+  NKSN_BeginMessage(session);
+
+  datum = htons(NKE_NEXT_PROTOCOL_NTPV4);
+  if (!NKSN_AddRecord(session, 1, NKE_RECORD_NEXT_PROTOCOL, &datum, sizeof (datum)))
+    return 0;
+
+  datum = htons(AEAD_AES_SIV_CMAC_256);
+  if (!NKSN_AddRecord(session, 1, NKE_RECORD_AEAD_ALGORITHM, &datum, sizeof (datum)))
+    return 0;
+
+  if (!NKSN_EndMessage(session))
+    return 0;
+
+  return 1;
+}
+
+/* ================================================== */
+
+static int
+process_response(NKC_Instance inst)
+{
+  int next_protocol = -1, aead_algorithm = -1, error = 0;
+  int i, critical, type, length;
+  uint16_t data[NKE_MAX_COOKIE_LENGTH / sizeof (uint16_t)];
+
+  assert(NKE_MAX_COOKIE_LENGTH % sizeof (uint16_t) == 0);
+  assert(sizeof (uint16_t) == 2);
+
+  inst->num_cookies = 0;
+  inst->ntp_address.ip_addr.family = IPADDR_UNSPEC;
+  inst->ntp_address.port = 0;
+  inst->server_name[0] = '\0';
+
+  while (!error) {
+    if (!NKSN_GetRecord(inst->session, &critical, &type, &length, &data, sizeof (data)))
+      break;
+
+    switch (type) {
+      case NKE_RECORD_NEXT_PROTOCOL:
+        if (!critical || length != 2 || ntohs(data[0]) != NKE_NEXT_PROTOCOL_NTPV4) {
+          DEBUG_LOG("Unexpected NTS-KE next protocol");
+          error = 1;
+          break;
+        }
+        next_protocol = NKE_NEXT_PROTOCOL_NTPV4;
+        break;
+      case NKE_RECORD_AEAD_ALGORITHM:
+        if (length != 2 || ntohs(data[0]) != AEAD_AES_SIV_CMAC_256) {
+          DEBUG_LOG("Unexpected NTS-KE AEAD algorithm");
+          error = 1;
+          break;
+        }
+        aead_algorithm = AEAD_AES_SIV_CMAC_256;
+        inst->siv_algorithm = aead_algorithm;
+        break;
+      case NKE_RECORD_ERROR:
+        if (length == 2)
+          DEBUG_LOG("NTS-KE error %d", ntohs(data[0]));
+        error = 1;
+        break;
+      case NKE_RECORD_WARNING:
+        if (length == 2)
+          DEBUG_LOG("NTS-KE warning %d", ntohs(data[0]));
+        error = 1;
+        break;
+      case NKE_RECORD_COOKIE:
+        DEBUG_LOG("Got cookie #%d length=%d", inst->num_cookies + 1, length);
+        assert(NKE_MAX_COOKIE_LENGTH == sizeof (inst->cookies[inst->num_cookies].cookie));
+        if (length <= NKE_MAX_COOKIE_LENGTH && inst->num_cookies < NKE_MAX_COOKIES) {
+          inst->cookies[inst->num_cookies].length = length;
+          memcpy(inst->cookies[inst->num_cookies].cookie, data, length);
+          inst->num_cookies++;
+        }
+        break;
+      case NKE_RECORD_NTPV4_SERVER_NEGOTIATION:
+        if (length < 1 || length >= sizeof (inst->server_name)) {
+          DEBUG_LOG("Invalid server name");
+          error = 1;
+          break;
+        }
+
+        memcpy(inst->server_name, data, length);
+        inst->server_name[length] = '\0';
+
+        /* Make sure the name is printable and has no spaces */
+        for (i = 0; i < length && isgraph(inst->server_name[i]); i++)
+          ;
+        if (i != length) {
+          DEBUG_LOG("Invalid server name");
+          error = 1;
+          break;
+        }
+
+        DEBUG_LOG("Negotiated server %s", inst->server_name);
+        break;
+      case NKE_RECORD_NTPV4_PORT_NEGOTIATION:
+        if (length != 2) {
+          DEBUG_LOG("Invalid port");
+          error = 1;
+          break;
+        }
+        inst->ntp_address.port = ntohs(data[0]);
+        DEBUG_LOG("Negotiated port %d", inst->ntp_address.port);
+        break;
+      default:
+        DEBUG_LOG("Unknown record type=%d length=%d critical=%d", type, length, critical);
+        if (critical)
+          error = 1;
+    }
+  }
+
+  DEBUG_LOG("NTS-KE response: error=%d next=%d aead=%d",
+            error, next_protocol, aead_algorithm);
+
+  if (error || inst->num_cookies == 0 ||
+      next_protocol != NKE_NEXT_PROTOCOL_NTPV4 ||
+      aead_algorithm != AEAD_AES_SIV_CMAC_256)
+    return 0;
+
+  return 1;
+}
+
+/* ================================================== */
+
+static int
+handle_message(void *arg)
+{
+  NKC_Instance inst = arg;
+
+  if (!process_response(inst)) {
+    LOG(LOGS_ERR, "Received invalid NTS-KE response from %s", inst->name);
+    return 0;
+  }
+
+  if (!NKSN_GetKeys(inst->session, inst->siv_algorithm, &inst->c2s, &inst->s2c))
+    return 0;
+
+  if (inst->server_name[0] != '\0') {
+    if (inst->resolving_name)
+      return 0;
+    if (!UTI_StringToIP(inst->server_name, &inst->ntp_address.ip_addr)) {
+      DNS_Name2IPAddressAsync(inst->server_name, name_resolve_handler, inst);
+      inst->resolving_name = 1;
+    }
+  }
+
+  inst->got_response = 1;
+
+  return 1;
+}
+
+/* ================================================== */
+
+void
+NKC_Initialise(void)
+{
+  client_credentials = NULL;
+}
+
+/* ================================================== */
+
+void
+NKC_Finalise(void)
+{
+  if (client_credentials)
+    NKSN_DestroyCertCredentials(client_credentials);
+}
+
+/* ================================================== */
+
+NKC_Instance
+NKC_CreateInstance(IPSockAddr *address, const char *name)
+{
+  NKC_Instance inst;
+
+  inst = MallocNew(struct NKC_Instance_Record);
+
+  inst->address = *address;
+  inst->name = Strdup(name);
+  inst->session = NKSN_CreateInstance(0, inst->name, handle_message, inst);
+  inst->resolving_name = 0;
+  inst->destroying = 0;
+  inst->got_response = 0;
+
+  /* Create the credentials with the first client instance and share them
+     with other instances */
+  if (!client_credentials)
+    client_credentials = NKSN_CreateCertCredentials(NULL, NULL, CNF_GetNtsTrustedCertFile());
+
+  return inst;
+}
+
+/* ================================================== */
+
+void
+NKC_DestroyInstance(NKC_Instance inst)
+{
+  /* If the resolver is running, destroy the instance later when finished */
+  if (inst->resolving_name) {
+    inst->destroying = 1;
+    return;
+  }
+
+  NKSN_DestroyInstance(inst->session);
+
+  Free(inst->name);
+  Free(inst);
+}
+
+/* ================================================== */
+
+int
+NKC_Start(NKC_Instance inst)
+{
+  IPSockAddr local_addr;
+  int sock_fd;
+
+  assert(!NKC_IsActive(inst));
+
+  if (!client_credentials) {
+    DEBUG_LOG("Missing client credentials");
+    return 0;
+  }
+
+  /* Follow the bindacqaddress setting */
+  CNF_GetBindAcquisitionAddress(inst->address.ip_addr.family, &local_addr.ip_addr);
+  if (local_addr.ip_addr.family != inst->address.ip_addr.family)
+    SCK_GetAnyLocalIPAddress(inst->address.ip_addr.family, &local_addr.ip_addr);
+
+  local_addr.port = 0;
+
+  sock_fd = SCK_OpenTcpSocket(&inst->address, &local_addr, 0);
+  if (sock_fd < 0)
+    return 0;
+
+  /* Start a NTS-KE session */
+  if (!NKSN_StartSession(inst->session, sock_fd, client_credentials, CLIENT_TIMEOUT)) {
+    SCK_CloseSocket(sock_fd);
+    return 0;
+  }
+
+  /* Send a request */
+  if (!prepare_request(inst)) {
+    DEBUG_LOG("Could not prepare NTS-KE request");
+    NKSN_StopSession(inst->session);
+    return 0;
+  }
+
+  return 1;
+}
+
+/* ================================================== */
+
+int
+NKC_IsActive(NKC_Instance inst)
+{
+  return !NKSN_IsStopped(inst->session) || inst->resolving_name;
+}
+
+/* ================================================== */
+
+int
+NKC_GetNtsData(NKC_Instance inst,
+               SIV_Algorithm *siv_algorithm, NKE_Key *c2s, NKE_Key *s2c,
+               NKE_Cookie *cookies, int *num_cookies, int max_cookies,
+               IPSockAddr *ntp_address)
+{
+  int i;
+
+  if (!inst->got_response || inst->resolving_name)
+    return 0;
+
+  *siv_algorithm = inst->siv_algorithm;
+  *c2s = inst->c2s;
+  *s2c = inst->s2c;
+
+  for (i = 0; i < inst->num_cookies && i < max_cookies; i++)
+    cookies[i] = inst->cookies[i];
+  *num_cookies = i;
+
+  *ntp_address = inst->ntp_address;
+
+  return i;
+}
--- a/nts_ke_client.h
+++ b/nts_ke_client.h
@@ -0,0 +1,58 @@
+/*
+  chronyd/chronyc - Programs for keeping computer clocks accurate.
+
+ **********************************************************************
+ * Copyright (C) Miroslav Lichvar  2020
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ * 
+ **********************************************************************
+
+  =======================================================================
+
+  Header file for the NTS-KE client
+  */
+
+#ifndef GOT_NTS_KE_CLIENT_H
+#define GOT_NTS_KE_CLIENT_H
+
+#include "addressing.h"
+#include "nts_ke.h"
+
+typedef struct NKC_Instance_Record *NKC_Instance;
+
+/* Init and fini functions */
+extern void NKC_Initialise(void);
+extern void NKC_Finalise(void);
+
+/* Create a client NTS-KE instance */
+extern NKC_Instance NKC_CreateInstance(IPSockAddr *address, const char *name);
+
+/* Destroy an instance */
+extern void NKC_DestroyInstance(NKC_Instance inst);
+
+/* Connect to the server, start an NTS-KE session, send an NTS-KE request, and
+   process the response (asynchronously) */
+extern int NKC_Start(NKC_Instance inst);
+
+/* Check if the client is still running */
+extern int NKC_IsActive(NKC_Instance inst);
+
+/* Get the NTS data if the session was successful */
+extern int NKC_GetNtsData(NKC_Instance inst,
+                          SIV_Algorithm *siv_algorithm, NKE_Key *c2s, NKE_Key *s2c,
+                          NKE_Cookie *cookies, int *num_cookies, int max_cookies,
+                          IPSockAddr *ntp_address);
+
+#endif
--- a/nts_ke_server.c
+++ b/nts_ke_server.c
@@ -0,0 +1,785 @@
+/*
+  chronyd/chronyc - Programs for keeping computer clocks accurate.
+
+ **********************************************************************
+ * Copyright (C) Miroslav Lichvar  2020
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ * 
+ **********************************************************************
+
+  =======================================================================
+
+  NTS-KE server
+  */
+
+#include "config.h"
+
+#include "sysincl.h"
+
+#include "nts_ke_server.h"
+
+#include "array.h"
+#include "conf.h"
+#include "clientlog.h"
+#include "logging.h"
+#include "memory.h"
+#include "ntp_core.h"
+#include "nts_ke_session.h"
+#include "siv.h"
+#include "socket.h"
+#include "sched.h"
+#include "sys.h"
+#include "util.h"
+
+#define SERVER_TIMEOUT 2.0
+
+#define SERVER_COOKIE_SIV AEAD_AES_SIV_CMAC_256
+#define SERVER_COOKIE_NONCE_LENGTH 16
+
+#define KEY_ID_INDEX_BITS 2
+#define MAX_SERVER_KEYS (1U << KEY_ID_INDEX_BITS)
+
+#define MIN_KEY_ROTATE_INTERVAL 1.0
+
+#define INVALID_SOCK_FD (-7)
+
+typedef struct {
+  uint32_t key_id;
+  uint8_t nonce[SERVER_COOKIE_NONCE_LENGTH];
+} ServerCookieHeader;
+
+typedef struct {
+  uint32_t id;
+  unsigned char key[SIV_MAX_KEY_LENGTH];
+  SIV_Instance siv;
+} ServerKey;
+
+typedef struct {
+  uint32_t key_id;
+  unsigned char key[SIV_MAX_KEY_LENGTH];
+  IPAddr client_addr;
+  uint16_t client_port;
+  uint16_t _pad;
+} HelperRequest;
+
+/* ================================================== */
+
+static ServerKey server_keys[MAX_SERVER_KEYS];
+static int current_server_key;
+
+static int server_sock_fd4;
+static int server_sock_fd6;
+
+static int helper_sock_fd;
+
+static int initialised = 0;
+
+/* Array of NKSN instances */
+static ARR_Instance sessions;
+static void *server_credentials;
+
+/* ================================================== */
+
+static int handle_message(void *arg);
+
+/* ================================================== */
+
+static int
+handle_client(int sock_fd, IPSockAddr *addr)
+{
+  NKSN_Instance inst, *instp;
+  int i;
+
+  if (sock_fd > FD_SETSIZE / 2) {
+    DEBUG_LOG("Rejected connection from %s (%s)",
+              UTI_IPSockAddrToString(addr), "too many descriptors");
+    return 0;
+  }
+
+  /* Find a slot which is free or has a stopped session */
+  for (i = 0, inst = NULL; i < ARR_GetSize(sessions); i++) {
+    instp = ARR_GetElement(sessions, i);
+    if (!*instp) {
+      /* NULL handler arg will be replaced with the session instance */
+      inst = NKSN_CreateInstance(1, UTI_IPSockAddrToString(addr), handle_message, NULL);
+      *instp = inst;
+      break;
+    } else if (NKSN_IsStopped(*instp)) {
+      inst = *instp;
+      break;
+    }
+  }
+
+  if (!inst) {
+    DEBUG_LOG("Rejected connection from %s (%s)",
+              UTI_IPSockAddrToString(addr), "too many connections");
+    return 0;
+  }
+
+  if (!NKSN_StartSession(inst, sock_fd, server_credentials, SERVER_TIMEOUT))
+    return 0;
+
+  return 1;
+}
+
+/* ================================================== */
+
+static void
+handle_helper_request(int fd, int event, void *arg)
+{
+  SCK_Message message;
+  HelperRequest *req;
+  IPSockAddr client_addr;
+  int sock_fd;
+
+  if (!SCK_ReceiveMessage(fd, &message, SCK_FLAG_MSG_DESCRIPTOR))
+    return;
+
+  sock_fd = message.descriptor;
+  if (sock_fd < 0) {
+    /* Message with no descriptor is a shutdown command */
+    SCH_QuitProgram();
+    return;
+  }
+
+  if (message.length != sizeof (HelperRequest)) {
+    DEBUG_LOG("Unexpected message length");
+    SCK_CloseSocket(sock_fd);
+    return;
+  }
+
+  req = message.data;
+
+  /* Extract the server key and client address from the request */
+  server_keys[current_server_key].id = ntohl(req->key_id);
+  memcpy(server_keys[current_server_key].key, req->key,
+         sizeof (server_keys[current_server_key].key));
+  UTI_IPNetworkToHost(&req->client_addr, &client_addr.ip_addr);
+  client_addr.port = ntohs(req->client_port);
+
+  if (!SIV_SetKey(server_keys[current_server_key].siv, server_keys[current_server_key].key,
+                  SIV_GetKeyLength(SERVER_COOKIE_SIV)))
+    assert(0);
+
+  if (!handle_client(sock_fd, &client_addr)) {
+    SCK_CloseSocket(sock_fd);
+    return;
+  }
+
+  DEBUG_LOG("Accepted helper request fd=%d", sock_fd);
+}
+
+/* ================================================== */
+
+static void
+accept_connection(int server_fd, int event, void *arg)
+{
+  SCK_Message message;
+  IPSockAddr addr;
+  int log_index, sock_fd;
+  struct timespec now;
+
+  sock_fd = SCK_AcceptConnection(server_fd, &addr);
+  if (sock_fd < 0)
+    return;
+
+  if (!NCR_CheckAccessRestriction(&addr.ip_addr)) {
+    DEBUG_LOG("Rejected connection from %s (%s)",
+              UTI_IPSockAddrToString(&addr), "access denied");
+    SCK_CloseSocket(sock_fd);
+    return;
+  }
+
+  SCH_GetLastEventTime(&now, NULL, NULL);
+  log_index = CLG_LogNTPAccess(&addr.ip_addr, &now);
+  if (log_index >= 0 && CLG_LimitNTPResponseRate(log_index)) {
+    DEBUG_LOG("Rejected connection from %s (%s)",
+              UTI_IPSockAddrToString(&addr), "rate limit");
+    SCK_CloseSocket(sock_fd);
+    return;
+  }
+
+  /* Pass the socket to a helper process if enabled.  Otherwise, handle the
+     client in the main process. */
+  if (helper_sock_fd != INVALID_SOCK_FD) {
+    HelperRequest req;
+
+    /* Include the current server key and client address in the request */
+    memset(&req, 0, sizeof (req));
+    req.key_id = htonl(server_keys[current_server_key].id);
+    memcpy(req.key, server_keys[current_server_key].key, sizeof (req.key));
+    UTI_IPHostToNetwork(&addr.ip_addr, &req.client_addr);
+    req.client_port = htons(addr.port);
+
+    SCK_InitMessage(&message, SCK_ADDR_UNSPEC);
+    message.data = &req;
+    message.length = sizeof (req);
+    message.descriptor = sock_fd;
+
+    if (!SCK_SendMessage(helper_sock_fd, &message, SCK_FLAG_MSG_DESCRIPTOR)) {
+      SCK_CloseSocket(sock_fd);
+      return;
+    }
+
+    SCK_CloseSocket(sock_fd);
+  } else {
+    if (!handle_client(sock_fd, &addr)) {
+      SCK_CloseSocket(sock_fd);
+      return;
+    }
+  }
+
+  DEBUG_LOG("Accepted connection from %s fd=%d", UTI_IPSockAddrToString(&addr), sock_fd);
+}
+
+/* ================================================== */
+
+static int
+open_socket(int family, int port)
+{
+  IPSockAddr local_addr;
+  int sock_fd;
+
+  if (!SCK_IsFamilySupported(family))
+    return INVALID_SOCK_FD;
+
+  CNF_GetBindAddress(family, &local_addr.ip_addr);
+
+  if (local_addr.ip_addr.family != family)
+    SCK_GetAnyLocalIPAddress(family, &local_addr.ip_addr);
+
+  local_addr.port = port;
+
+  sock_fd = SCK_OpenTcpSocket(NULL, &local_addr, 0);
+  if (sock_fd < 0) {
+    LOG(LOGS_ERR, "Could not open NTS-KE socket on %s", UTI_IPSockAddrToString(&local_addr));
+    return INVALID_SOCK_FD;
+  }
+
+  if (!SCK_ListenOnSocket(sock_fd, CNF_GetNtsServerConnections())) {
+    SCK_CloseSocket(sock_fd);
+    return INVALID_SOCK_FD;
+  }
+
+  SCH_AddFileHandler(sock_fd, SCH_FILE_INPUT, accept_connection, NULL);
+
+  return sock_fd;
+}
+
+/* ================================================== */
+
+static void
+helper_signal(int x)
+{
+  SCH_QuitProgram();
+}
+
+/* ================================================== */
+
+static int
+prepare_response(NKSN_Instance session, int error, int next_protocol, int aead_algorithm)
+{
+  NKE_Cookie cookie;
+  NKE_Key c2s, s2c;
+  uint16_t datum;
+  int i;
+
+  DEBUG_LOG("NTS KE response: error=%d next=%d aead=%d", error, next_protocol, aead_algorithm);
+
+  NKSN_BeginMessage(session);
+
+  if (error >= 0) {
+    datum = htons(error);
+    if (!NKSN_AddRecord(session, 1, NKE_RECORD_ERROR, &datum, sizeof (datum)))
+      return 0;
+  } else {
+    datum = htons(next_protocol);
+    if (!NKSN_AddRecord(session, 1, NKE_RECORD_NEXT_PROTOCOL, &datum, sizeof (datum)))
+      return 0;
+
+    datum = htons(aead_algorithm);
+    if (!NKSN_AddRecord(session, 1, NKE_RECORD_AEAD_ALGORITHM, &datum, sizeof (datum)))
+      return 0;
+
+    if (CNF_GetNTPPort() != NTP_PORT) {
+      datum = htons(CNF_GetNTPPort());
+      if (!NKSN_AddRecord(session, 1, NKE_RECORD_NTPV4_PORT_NEGOTIATION, &datum, sizeof (datum)))
+        return 0;
+    }
+
+    /* This should be configurable */
+    if (0) {
+      const char server[] = "::1";
+      if (!NKSN_AddRecord(session, 1, NKE_RECORD_NTPV4_SERVER_NEGOTIATION, server,
+                          sizeof (server) - 1))
+        return 0;
+    }
+
+    if (!NKSN_GetKeys(session, aead_algorithm, &c2s, &s2c))
+      return 0;
+
+    for (i = 0; i < NKE_MAX_COOKIES; i++) {
+      if (!NKS_GenerateCookie(&c2s, &s2c, &cookie))
+        return 0;
+      if (!NKSN_AddRecord(session, 0, NKE_RECORD_COOKIE, cookie.cookie, cookie.length))
+        return 0;
+    }
+  }
+
+  if (!NKSN_EndMessage(session))
+    return 0;
+
+  return 1;
+}
+
+/* ================================================== */
+
+static int
+process_request(NKSN_Instance session)
+{
+  int next_protocol = -1, aead_algorithm = -1, error = -1;
+  int i, critical, type, length;
+  uint16_t data[NKE_MAX_RECORD_BODY_LENGTH / sizeof (uint16_t)];
+
+  assert(NKE_MAX_RECORD_BODY_LENGTH % sizeof (uint16_t) == 0);
+  assert(sizeof (uint16_t) == 2);
+
+  while (error == -1) {
+    if (!NKSN_GetRecord(session, &critical, &type, &length, &data, sizeof (data)))
+      break;
+
+    switch (type) {
+      case NKE_RECORD_NEXT_PROTOCOL:
+        if (!critical || length < 2 || length % 2 != 0) {
+          error = NKE_ERROR_BAD_REQUEST;
+          break;
+        }
+        for (i = 0; i < MIN(length, sizeof (data)) / 2; i++) {
+          if (ntohs(data[i]) == NKE_NEXT_PROTOCOL_NTPV4)
+            next_protocol = NKE_NEXT_PROTOCOL_NTPV4;
+        }
+        break;
+      case NKE_RECORD_AEAD_ALGORITHM:
+        if (length < 2 || length % 2 != 0) {
+          error = NKE_ERROR_BAD_REQUEST;
+          break;
+        }
+        for (i = 0; i < MIN(length, sizeof (data)) / 2; i++) {
+          if (ntohs(data[i]) == AEAD_AES_SIV_CMAC_256)
+            aead_algorithm = AEAD_AES_SIV_CMAC_256;
+        }
+        break;
+      case NKE_RECORD_ERROR:
+      case NKE_RECORD_WARNING:
+      case NKE_RECORD_COOKIE:
+        error = NKE_ERROR_BAD_REQUEST;
+        break;
+      default:
+        if (critical)
+          error = NKE_ERROR_UNRECOGNIZED_CRITICAL_RECORD;
+    }
+  }
+
+  if (aead_algorithm < 0 || next_protocol < 0)
+    error = NKE_ERROR_BAD_REQUEST;
+
+  if (!prepare_response(session, error, next_protocol, aead_algorithm))
+    return 0;
+
+  return 1;
+}
+
+/* ================================================== */
+
+static int
+handle_message(void *arg)
+{
+  NKSN_Instance session = arg;
+
+  return process_request(session);
+}
+
+/* ================================================== */
+
+static void
+generate_key(int index)
+{
+  int key_length;
+
+  assert(index < MAX_SERVER_KEYS);
+
+  key_length = SIV_GetKeyLength(SERVER_COOKIE_SIV);
+  if (key_length > sizeof (server_keys[index].key))
+    assert(0);
+
+  UTI_GetRandomBytesUrandom(server_keys[index].key, key_length);
+  if (!SIV_SetKey(server_keys[index].siv, server_keys[index].key, key_length))
+    assert(0);
+
+  UTI_GetRandomBytes(&server_keys[index].id, sizeof (server_keys[index].id));
+
+  server_keys[index].id &= -1U << KEY_ID_INDEX_BITS;
+  server_keys[index].id |= index;
+
+  DEBUG_LOG("Generated server key %"PRIX32, server_keys[index].id);
+}
+
+/* ================================================== */
+
+static void
+save_keys(void)
+{
+  char hex_key[SIV_MAX_KEY_LENGTH * 2 + 1];
+  int i, index, key_length;
+  char *cachedir;
+  FILE *f;
+
+  cachedir = CNF_GetNtsCacheDir();
+  if (!cachedir)
+    return;
+
+  f = UTI_OpenFile(cachedir, "ntskeys", ".tmp", 'w', 0600);
+  if (!f)
+    return;
+
+  key_length = SIV_GetKeyLength(SERVER_COOKIE_SIV);
+
+  for (i = 0; i < MAX_SERVER_KEYS; i++) {
+    index = (current_server_key + i + 1) % MAX_SERVER_KEYS;
+
+    if (key_length > sizeof (server_keys[index].key) ||
+        !UTI_BytesToHex(server_keys[index].key, key_length, hex_key, sizeof (hex_key))) {
+      assert(0);
+      break;
+    }
+
+    fprintf(f, "%08"PRIX32" %s\n", server_keys[index].id, hex_key);
+  }
+
+  fclose(f);
+
+  if (!UTI_RenameTempFile(cachedir, "ntskeys", ".tmp", NULL))
+    ;
+}
+
+/* ================================================== */
+
+static void
+load_keys(void)
+{
+  int i, index, line_length, key_length, n;
+  char *cachedir, line[1024];
+  FILE *f;
+  uint32_t id;
+
+  cachedir = CNF_GetNtsCacheDir();
+  if (!cachedir)
+    return;
+
+  f = UTI_OpenFile(cachedir, "ntskeys", NULL, 'r', 0);
+  if (!f)
+    return;
+
+  key_length = SIV_GetKeyLength(SERVER_COOKIE_SIV);
+
+  for (i = 0; i < MAX_SERVER_KEYS; i++) {
+    if (!fgets(line, sizeof (line), f))
+      break;
+
+    line_length = strlen(line);
+    if (line_length < 10)
+      break;
+    /* Drop '\n' */
+    line[line_length - 1] = '\0';
+
+    if (sscanf(line, "%"PRIX32"%n", &id, &n) != 1 || line[n] != ' ')
+      break;
+
+    index = id % MAX_SERVER_KEYS;
+
+    if (UTI_HexToBytes(line + n + 1, server_keys[index].key,
+                       sizeof (server_keys[index].key)) != key_length)
+      break;
+
+    server_keys[index].id = id;
+    if (!SIV_SetKey(server_keys[index].siv, server_keys[index].key, key_length))
+      assert(0);
+
+    DEBUG_LOG("Loaded key %"PRIX32, id);
+
+    current_server_key = index;
+  }
+
+  fclose(f);
+}
+
+/* ================================================== */
+
+static void
+key_timeout(void *arg)
+{
+  current_server_key = (current_server_key + 1) % MAX_SERVER_KEYS;
+  generate_key(current_server_key);
+  save_keys();
+
+  SCH_AddTimeoutByDelay(MAX(CNF_GetNtsRotate(), MIN_KEY_ROTATE_INTERVAL),
+                        key_timeout, NULL);
+}
+
+/* ================================================== */
+
+static void
+start_helper(int id, int scfilter_level, int main_fd, int helper_fd)
+{
+  pid_t pid;
+
+  pid = fork();
+
+  if (pid < 0)
+    LOG_FATAL("fork() failed : %s", strerror(errno));
+
+  if (pid > 0)
+    return;
+
+  SCK_CloseSocket(main_fd);
+
+  LOG_CloseParentFd();
+  SCH_Reset();
+  SCH_AddFileHandler(helper_fd, SCH_FILE_INPUT, handle_helper_request, NULL);
+  UTI_SetQuitSignalsHandler(helper_signal, 1);
+  if (scfilter_level != 0)
+    SYS_EnableSystemCallFilter(scfilter_level, SYS_NTSKE_HELPER);
+
+  initialised = 1;
+
+  DEBUG_LOG("NTS-KE helper #%d started", id);
+
+  SCH_MainLoop();
+
+  NKS_Finalise();
+
+  DEBUG_LOG("NTS-KE helper #%d exiting", id);
+
+  exit(0);
+}
+
+/* ================================================== */
+
+void
+NKS_Initialise(int scfilter_level)
+{
+  char *cert, *key;
+  int i, processes;
+
+  server_sock_fd4 = INVALID_SOCK_FD;
+  server_sock_fd6 = INVALID_SOCK_FD;
+  helper_sock_fd = INVALID_SOCK_FD;
+
+  cert = CNF_GetNtsServerCertFile();
+  key = CNF_GetNtsServerKeyFile();
+
+  if (!cert || !key)
+    return;
+
+  server_credentials = NKSN_CreateCertCredentials(cert, key, NULL);
+  if (!server_credentials)
+    return;
+
+  sessions = ARR_CreateInstance(sizeof (NKSN_Instance));
+  for (i = 0; i < CNF_GetNtsServerConnections(); i++)
+    *(NKSN_Instance *)ARR_GetNewElement(sessions) = NULL;
+  for (i = 0; i < MAX_SERVER_KEYS; i++)
+    server_keys[i].siv = NULL;
+
+  server_sock_fd4 = open_socket(IPADDR_INET4, CNF_GetNtsServerPort());
+  server_sock_fd6 = open_socket(IPADDR_INET6, CNF_GetNtsServerPort());
+
+  for (i = 0; i < MAX_SERVER_KEYS; i++) {
+    server_keys[i].siv = SIV_CreateInstance(SERVER_COOKIE_SIV);
+    generate_key(i);
+  }
+
+  current_server_key = MAX_SERVER_KEYS - 1;
+
+  load_keys();
+
+  key_timeout(NULL);
+
+  processes = CNF_GetNtsServerProcesses();
+
+  if (processes > 0) {
+    int sock_fd1, sock_fd2;
+
+    sock_fd1 = SCK_OpenUnixSocketPair(0, &sock_fd2);
+
+    for (i = 0; i < processes; i++)
+      start_helper(i + 1, scfilter_level, sock_fd1, sock_fd2);
+
+    SCK_CloseSocket(sock_fd2);
+    helper_sock_fd = sock_fd1;
+  }
+
+  initialised = 1;
+}
+
+/* ================================================== */
+
+void
+NKS_Finalise(void)
+{
+  int i;
+
+  if (!initialised)
+    return;
+
+  if (helper_sock_fd != INVALID_SOCK_FD) {
+    for (i = 0; i < CNF_GetNtsServerProcesses(); i++) {
+      if (!SCK_Send(helper_sock_fd, "", 1, 0))
+        ;
+    }
+    SCK_CloseSocket(helper_sock_fd);
+  }
+  if (server_sock_fd4 != INVALID_SOCK_FD)
+    SCK_CloseSocket(server_sock_fd4);
+  if (server_sock_fd6 != INVALID_SOCK_FD)
+    SCK_CloseSocket(server_sock_fd6);
+
+  save_keys();
+  for (i = 0; i < MAX_SERVER_KEYS; i++) {
+    if (server_keys[i].siv != NULL)
+      SIV_DestroyInstance(server_keys[i].siv);
+  }
+
+  for (i = 0; i < ARR_GetSize(sessions); i++) {
+    NKSN_Instance session = *(NKSN_Instance *)ARR_GetElement(sessions, i);
+    if (session)
+      NKSN_DestroyInstance(session);
+  }
+  ARR_DestroyInstance(sessions);
+
+  NKSN_DestroyCertCredentials(server_credentials);
+}
+
+/* ================================================== */
+
+/* A server cookie consists of key ID, nonce, and encrypted C2S+S2C keys */
+
+int
+NKS_GenerateCookie(NKE_Key *c2s, NKE_Key *s2c, NKE_Cookie *cookie)
+{
+  unsigned char plaintext[2 * NKE_MAX_KEY_LENGTH], *ciphertext;
+  int plaintext_length, tag_length;
+  ServerCookieHeader *header;
+  ServerKey *key;
+
+  if (!initialised) {
+    DEBUG_LOG("NTS server disabled");
+    return 0;
+  }
+
+  if (c2s->length < 0 || c2s->length > NKE_MAX_KEY_LENGTH ||
+      s2c->length < 0 || s2c->length > NKE_MAX_KEY_LENGTH) {
+    DEBUG_LOG("Invalid key length");
+    return 0;
+  }
+
+  key = &server_keys[current_server_key];
+
+  header = (ServerCookieHeader *)cookie->cookie;
+
+  /* Keep the fields in the host byte order */
+  header->key_id = key->id;
+  UTI_GetRandomBytes(header->nonce, sizeof (header->nonce));
+
+  plaintext_length = c2s->length + s2c->length;
+  assert(plaintext_length <= sizeof (plaintext));
+  memcpy(plaintext, c2s->key, c2s->length);
+  memcpy(plaintext + c2s->length, s2c->key, s2c->length);
+
+  tag_length = SIV_GetTagLength(key->siv);
+  cookie->length = sizeof (*header) + plaintext_length + tag_length;
+  assert(cookie->length <= sizeof (cookie->cookie));
+  ciphertext = cookie->cookie + sizeof (*header);
+
+  if (!SIV_Encrypt(key->siv, header->nonce, sizeof (header->nonce),
+                   "", 0,
+                   plaintext, plaintext_length,
+                   ciphertext, plaintext_length + tag_length)) {
+    DEBUG_LOG("Could not encrypt cookie");
+    return 0;
+  }
+
+  return 1;
+}
+
+/* ================================================== */
+
+int
+NKS_DecodeCookie(NKE_Cookie *cookie, NKE_Key *c2s, NKE_Key *s2c)
+{
+  unsigned char plaintext[2 * NKE_MAX_KEY_LENGTH], *ciphertext;
+  int ciphertext_length, plaintext_length, tag_length;
+  ServerCookieHeader *header;
+  ServerKey *key;
+
+  if (!initialised) {
+    DEBUG_LOG("NTS server disabled");
+    return 0;
+  }
+
+  if (cookie->length <= sizeof (*header)) {
+    DEBUG_LOG("Invalid cookie length");
+    return 0;
+  }
+
+  header = (ServerCookieHeader *)cookie->cookie;
+  ciphertext = cookie->cookie + sizeof (*header);
+  ciphertext_length = cookie->length - sizeof (*header);
+
+  key = &server_keys[header->key_id % MAX_SERVER_KEYS];
+  if (header->key_id != key->id) {
+    DEBUG_LOG("Unknown key %"PRIX32, header->key_id);
+    return 0;
+  }
+
+  tag_length = SIV_GetTagLength(key->siv);
+  if (tag_length >= ciphertext_length) {
+    DEBUG_LOG("Invalid cookie length");
+    return 0;
+  }
+
+  plaintext_length = ciphertext_length - tag_length;
+  if (plaintext_length > sizeof (plaintext) || plaintext_length % 2 != 0) {
+    DEBUG_LOG("Invalid cookie length");
+    return 0;
+  }
+
+  if (!SIV_Decrypt(key->siv, header->nonce, sizeof (header->nonce),
+                   "", 0,
+                   ciphertext, ciphertext_length,
+                   plaintext, plaintext_length)) {
+    DEBUG_LOG("Could not decrypt cookie");
+    return 0;
+  }
+
+  c2s->length = plaintext_length / 2;
+  s2c->length = plaintext_length / 2;
+  assert(c2s->length <= sizeof (c2s->key));
+
+  memcpy(c2s->key, plaintext, c2s->length);
+  memcpy(s2c->key, plaintext + c2s->length, s2c->length);
+
+  return 1;
+}
--- a/nts_ke_server.h
+++ b/nts_ke_server.h
@@ -0,0 +1,42 @@
+/*
+  chronyd/chronyc - Programs for keeping computer clocks accurate.
+
+ **********************************************************************
+ * Copyright (C) Miroslav Lichvar  2020
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ * 
+ **********************************************************************
+
+  =======================================================================
+
+  Header file for the NTS-KE server
+  */
+
+#ifndef GOT_NTS_KE_SERVER_H
+#define GOT_NTS_KE_SERVER_H
+
+#include "nts_ke.h"
+
+/* Init and fini functions */
+extern void NKS_Initialise(int scfilter_level);
+extern void NKS_Finalise(void);
+
+/* Generate a new NTS cookie containing the C2S and S2C keys */
+extern int NKS_GenerateCookie(NKE_Key *c2s, NKE_Key *s2c, NKE_Cookie *cookie);
+
+/* Validate a cookie and extract the C2S and S2C keys */
+extern int NKS_DecodeCookie(NKE_Cookie *cookie, NKE_Key *c2s, NKE_Key *s2c);
+
+#endif
--- a/nts_ke_session.c
+++ b/nts_ke_session.c
@@ -0,0 +1,779 @@
+/*
+  chronyd/chronyc - Programs for keeping computer clocks accurate.
+
+ **********************************************************************
+ * Copyright (C) Miroslav Lichvar  2020
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ * 
+ **********************************************************************
+
+  =======================================================================
+
+  NTS-KE session used by server and client
+  */
+
+#include "config.h"
+
+#include "sysincl.h"
+
+#include "nts_ke_session.h"
+
+#include "conf.h"
+#include "logging.h"
+#include "memory.h"
+#include "siv.h"
+#include "socket.h"
+#include "sched.h"
+#include "util.h"
+
+#include <gnutls/gnutls.h>
+
+#define INVALID_SOCK_FD (-8)
+
+struct RecordHeader {
+  uint16_t type;
+  uint16_t body_length;
+};
+
+struct Message {
+  int length;
+  int sent;
+  int parsed;
+  int complete;
+  unsigned char data[NKE_MAX_MESSAGE_LENGTH];
+};
+
+typedef enum {
+  KE_WAIT_CONNECT,
+  KE_HANDSHAKE,
+  KE_SEND,
+  KE_RECEIVE,
+  KE_SHUTDOWN,
+  KE_STOPPED,
+} KeState;
+
+struct NKSN_Instance_Record {
+  int server;
+  char *name;
+  NKSN_MessageHandler handler;
+  void *handler_arg;
+
+  KeState state;
+  int sock_fd;
+  gnutls_session_t tls_session;
+  SCH_TimeoutID timeout_id;
+
+  struct Message message;
+  int new_message;
+  int ended_message;
+};
+
+/* ================================================== */
+
+static gnutls_priority_t priority_cache;
+
+static int credentials_counter = 0;
+
+/* ================================================== */
+
+static void
+reset_message(struct Message *message)
+{
+  message->length = 0;
+  message->sent = 0;
+  message->parsed = 0;
+  message->complete = 0;
+}
+
+/* ================================================== */
+
+static int
+add_record(struct Message *message, int critical, int type, const void *body, int body_length)
+{
+  struct RecordHeader header;
+
+  if (body_length < 0 || body_length > 0xffff || type < 0 || type > 0x7fff ||
+      message->length + sizeof (header) + body_length > sizeof (message->data))
+    return 0;
+
+  header.type = htons(!!critical * NKE_RECORD_CRITICAL_BIT | type);
+  header.body_length = htons(body_length);
+
+  memcpy(&message->data[message->length], &header, sizeof (header));
+  message->length += sizeof (header);
+
+  if (body_length > 0) {
+    memcpy(&message->data[message->length], body, body_length);
+    message->length += body_length;
+  }
+
+  return 1;
+}
+
+/* ================================================== */
+
+static void
+reset_message_parsing(struct Message *message)
+{
+  message->parsed = 0;
+}
+
+/* ================================================== */
+
+static int
+get_record(struct Message *message, int *critical, int *type, int *body_length,
+           void *body, int buffer_length)
+{
+  struct RecordHeader header;
+  int blen, rlen;
+
+  if (message->length < message->parsed + sizeof (header) ||
+      buffer_length < 0)
+    return 0;
+
+  memcpy(&header, &message->data[message->parsed], sizeof (header));
+
+  blen = ntohs(header.body_length);
+  rlen = sizeof (header) + blen;
+
+  if (message->length < message->parsed + rlen)
+    return 0;
+
+  if (critical)
+    *critical = !!(ntohs(header.type) & NKE_RECORD_CRITICAL_BIT);
+  if (type)
+    *type = ntohs(header.type) & ~NKE_RECORD_CRITICAL_BIT;
+  if (body)
+    memcpy(body, &message->data[message->parsed + sizeof (header)], MIN(buffer_length, blen));
+  if (body_length)
+    *body_length = blen;
+
+  message->parsed += rlen;
+
+  return 1;
+}
+
+/* ================================================== */
+
+static int
+check_message_format(struct Message *message, int eof)
+{
+  int critical = 0, type = -1, length = -1, ends = 0;
+
+  reset_message_parsing(message);
+  message->complete = 0;
+
+  while (get_record(message, &critical, &type, &length, NULL, 0)) {
+    if (type == NKE_RECORD_END_OF_MESSAGE) {
+      if (!critical || length != 0 || ends > 0)
+        return 0;
+      ends++;
+    }
+  }
+
+  /* If the message cannot be fully parsed, but more data may be coming,
+     consider the format to be ok */
+  if (message->length == 0 || message->parsed < message->length)
+    return !eof;
+
+  if (type != NKE_RECORD_END_OF_MESSAGE)
+    return !eof;
+
+  message->complete = 1;
+
+  return 1;
+}
+
+/* ================================================== */
+
+static gnutls_session_t
+create_tls_session(int server_mode, int sock_fd, const char *server_name,
+                   gnutls_certificate_credentials_t credentials,
+                   gnutls_priority_t priority)
+{
+  unsigned char alpn_name[sizeof (NKE_ALPN_NAME)];
+  gnutls_session_t session;
+  gnutls_datum_t alpn;
+  int r;
+
+  r = gnutls_init(&session, GNUTLS_NONBLOCK | (server_mode ? GNUTLS_SERVER : GNUTLS_CLIENT));
+  if (r < 0) {
+    LOG(LOGS_ERR, "Could not %s TLS session : %s", "create", gnutls_strerror(r));
+    return NULL;
+  }
+
+  if (!server_mode) {
+    r = gnutls_server_name_set(session, GNUTLS_NAME_DNS, server_name, strlen(server_name));
+    if (r < 0)
+      goto error;
+    gnutls_session_set_verify_cert(session, server_name, 0);
+  }
+
+  r = gnutls_priority_set(session, priority);
+  if (r < 0)
+    goto error;
+
+  r = gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE, credentials);
+  if (r < 0)
+    goto error;
+
+  memcpy(alpn_name, NKE_ALPN_NAME, sizeof (alpn_name));
+  alpn.data = alpn_name;
+  alpn.size = sizeof (alpn_name) - 1;
+
+  r = gnutls_alpn_set_protocols(session, &alpn, 1, 0);
+  if (r < 0)
+    goto error;
+
+  gnutls_transport_set_int(session, sock_fd);
+
+  return session;
+
+error:
+  LOG(LOGS_ERR, "Could not %s TLS session : %s", "set", gnutls_strerror(r));
+  gnutls_deinit(session);
+  return NULL;
+}
+
+/* ================================================== */
+
+static void
+stop_session(NKSN_Instance inst)
+{
+  if (inst->state == KE_STOPPED)
+    return;
+
+  inst->state = KE_STOPPED;
+
+  SCH_RemoveFileHandler(inst->sock_fd);
+  SCK_CloseSocket(inst->sock_fd);
+  inst->sock_fd = INVALID_SOCK_FD;
+
+  gnutls_deinit(inst->tls_session);
+  inst->tls_session = NULL;
+
+  SCH_RemoveTimeout(inst->timeout_id);
+  inst->timeout_id = 0;
+}
+
+/* ================================================== */
+
+static void
+session_timeout(void *arg)
+{
+  NKSN_Instance inst = arg;
+
+  LOG(inst->server ? LOGS_DEBUG : LOGS_ERR, "NTS-KE session with %s timed out", inst->name);
+
+  inst->timeout_id = 0;
+  stop_session(inst);
+}
+
+/* ================================================== */
+
+static int
+get_socket_error(int sock_fd)
+{
+  int optval;
+  socklen_t optlen = sizeof (optval);
+
+  if (getsockopt(sock_fd, SOL_SOCKET, SO_ERROR, &optval, &optlen) < 0) {
+    DEBUG_LOG("getsockopt() failed : %s", strerror(errno));
+    return EINVAL;
+  }
+
+  return optval;
+}
+
+/* ================================================== */
+
+static int
+check_alpn(NKSN_Instance inst)
+{
+  gnutls_datum_t alpn;
+  int r;
+
+  r = gnutls_alpn_get_selected_protocol(inst->tls_session, &alpn);
+  if (r < 0 || alpn.size != sizeof (NKE_ALPN_NAME) - 1 ||
+      strncmp((const char *)alpn.data, NKE_ALPN_NAME, sizeof (NKE_ALPN_NAME) - 1))
+    return 0;
+
+  return 1;
+}
+
+/* ================================================== */
+
+static void
+change_state(NKSN_Instance inst, KeState state)
+{
+  int output;
+
+  switch (state) {
+    case KE_HANDSHAKE:
+      output = !inst->server;
+      break;
+    case KE_WAIT_CONNECT:
+    case KE_SEND:
+    case KE_SHUTDOWN:
+      output = 1;
+      break;
+    case KE_RECEIVE:
+      output = 0;
+      break;
+    default:
+      assert(0);
+  }
+
+  SCH_SetFileHandlerEvent(inst->sock_fd, SCH_FILE_OUTPUT, output);
+
+  inst->state = state;
+}
+
+/* ================================================== */
+
+static int
+handle_event(NKSN_Instance inst, int event)
+{
+  struct Message *message = &inst->message;
+  int r;
+
+  DEBUG_LOG("Session event %d fd=%d state=%d", event, inst->sock_fd, (int)inst->state);
+
+  switch (inst->state) {
+    case KE_WAIT_CONNECT:
+      /* Check if connect() succeeded */
+      if (event != SCH_FILE_OUTPUT)
+        return 0;
+
+      r = get_socket_error(inst->sock_fd);
+
+      if (r) {
+        LOG(LOGS_ERR, "Could not connect to %s : %s", inst->name, strerror(r));
+        stop_session(inst);
+        return 0;
+      }
+
+      DEBUG_LOG("Connected to %s", inst->name);
+
+      change_state(inst, KE_HANDSHAKE);
+      return 0;
+
+    case KE_HANDSHAKE:
+      r = gnutls_handshake(inst->tls_session);
+
+      if (r < 0) {
+        if (gnutls_error_is_fatal(r)) {
+          LOG(inst->server ? LOGS_DEBUG : LOGS_ERR,
+              "TLS handshake with %s failed : %s", inst->name, gnutls_strerror(r));
+          stop_session(inst);
+          return 0;
+        }
+
+        /* Disable output when the handshake is trying to receive data */
+        SCH_SetFileHandlerEvent(inst->sock_fd, SCH_FILE_OUTPUT,
+                                gnutls_record_get_direction(inst->tls_session));
+        return 0;
+      }
+
+      if (DEBUG) {
+        char *description = gnutls_session_get_desc(inst->tls_session);
+        DEBUG_LOG("Handshake with %s completed %s",
+                  inst->name, description ? description : "");
+        gnutls_free(description);
+      }
+
+      if (!check_alpn(inst)) {
+        LOG(inst->server ? LOGS_DEBUG : LOGS_ERR, "NTS-KE not supported by %s", inst->name);
+        stop_session(inst);
+        return 0;
+      }
+
+      /* Client will send a request to the server */
+      change_state(inst, inst->server ? KE_RECEIVE : KE_SEND);
+      return 0;
+
+    case KE_SEND:
+      assert(inst->new_message && message->complete);
+
+      r = gnutls_record_send(inst->tls_session, &message->data[message->sent],
+                             message->length - message->sent);
+
+      if (r < 0) {
+        if (gnutls_error_is_fatal(r)) {
+          LOG(inst->server ? LOGS_DEBUG : LOGS_ERR,
+              "Could not send NTS-KE message to %s : %s", inst->name, gnutls_strerror(r));
+          stop_session(inst);
+        }
+        return 0;
+      }
+
+      DEBUG_LOG("Sent %d bytes to %s", r, inst->name);
+
+      message->sent += r;
+      if (message->sent < message->length)
+        return 0;
+
+      /* Client will receive a response */
+      change_state(inst, inst->server ? KE_SHUTDOWN : KE_RECEIVE);
+      reset_message(&inst->message);
+      inst->new_message = 0;
+      return 0;
+
+    case KE_RECEIVE:
+      do {
+        if (message->length >= sizeof (message->data)) {
+          DEBUG_LOG("Message is too long");
+          stop_session(inst);
+          return 0;
+        }
+
+        r = gnutls_record_recv(inst->tls_session, &message->data[message->length],
+                               sizeof (message->data) - message->length);
+
+        if (r < 0) {
+          /* Handle a renegotiation request on both client and server as
+             a protocol error */
+          if (gnutls_error_is_fatal(r) || r == GNUTLS_E_REHANDSHAKE) {
+            LOG(inst->server ? LOGS_DEBUG : LOGS_ERR,
+                "Could not receive NTS-KE message from %s : %s",
+                inst->name, gnutls_strerror(r));
+            stop_session(inst);
+          }
+          return 0;
+        }
+
+        DEBUG_LOG("Received %d bytes from %s", r, inst->name);
+
+        message->length += r;
+
+      } while (gnutls_record_check_pending(inst->tls_session) > 0);
+
+      if (!check_message_format(message, r == 0)) {
+        LOG(inst->server ? LOGS_DEBUG : LOGS_ERR,
+            "Received invalid NTS-KE message from %s", inst->name);
+        stop_session(inst);
+        return 0;
+      }
+
+      /* Wait for more data if the message is not complete yet */
+      if (!message->complete)
+        return 0;
+
+      /* Server will send a response to the client */
+      change_state(inst, inst->server ? KE_SEND : KE_SHUTDOWN);
+      break;
+
+    case KE_SHUTDOWN:
+      r = gnutls_bye(inst->tls_session, GNUTLS_SHUT_RDWR);
+
+      if (r < 0) {
+        if (gnutls_error_is_fatal(r)) {
+          DEBUG_LOG("Shutdown with %s failed : %s", inst->name, gnutls_strerror(r));
+          stop_session(inst);
+          return 0;
+        }
+
+        /* Disable output when the TLS shutdown is trying to receive data */
+        SCH_SetFileHandlerEvent(inst->sock_fd, SCH_FILE_OUTPUT,
+                                gnutls_record_get_direction(inst->tls_session));
+        return 0;
+      }
+
+      SCK_ShutdownConnection(inst->sock_fd);
+      stop_session(inst);
+
+      DEBUG_LOG("Shutdown completed");
+      return 0;
+
+    default:
+      assert(0);
+  }
+
+  return 1;
+}
+
+/* ================================================== */
+
+static void
+read_write_socket(int fd, int event, void *arg)
+{
+  NKSN_Instance inst = arg;
+
+  if (!handle_event(inst, event))
+    return;
+
+  reset_message_parsing(&inst->message);
+
+  if (!(inst->handler)(inst->handler_arg)) {
+    stop_session(inst);
+    return;
+  }
+}
+
+/* ================================================== */
+
+static int gnutls_initialised = 0;
+
+static void
+init_gnutls(void)
+{
+  int r;
+
+  if (gnutls_initialised)
+    return;
+
+  r = gnutls_global_init();
+  if (r < 0)
+    LOG_FATAL("Could not initialise %s : %s", "gnutls", gnutls_strerror(r));
+
+  /* NTS specification requires TLS1.2 or later */
+  r = gnutls_priority_init2(&priority_cache, "-VERS-SSL3.0:-VERS-TLS1.0:-VERS-TLS1.1",
+                            NULL, GNUTLS_PRIORITY_INIT_DEF_APPEND);
+  if (r < 0)
+    LOG_FATAL("Could not initialise %s : %s", "priority cache", gnutls_strerror(r));
+
+  gnutls_initialised = 1;
+}
+
+/* ================================================== */
+
+static void
+deinit_gnutls(void)
+{
+  assert(gnutls_initialised);
+
+  gnutls_priority_deinit(priority_cache);
+  gnutls_global_deinit();
+  gnutls_initialised = 0;
+}
+
+/* ================================================== */
+
+void *
+NKSN_CreateCertCredentials(char *cert, char *key, char *trusted_certs)
+{
+  gnutls_certificate_credentials_t credentials = NULL;
+  int r;
+
+  init_gnutls();
+
+  r = gnutls_certificate_allocate_credentials(&credentials);
+  if (r < 0)
+    goto error;
+
+  if (cert && key) {
+    r = gnutls_certificate_set_x509_key_file(credentials, cert, key,
+                                             GNUTLS_X509_FMT_PEM);
+    if (r < 0)
+      goto error;
+  } else {
+    if (!CNF_GetNoSystemCert()) {
+      r = gnutls_certificate_set_x509_system_trust(credentials);
+      if (r < 0)
+        goto error;
+    }
+
+    if (trusted_certs) {
+      r = gnutls_certificate_set_x509_trust_file(credentials, trusted_certs,
+                                                 GNUTLS_X509_FMT_PEM);
+      if (r < 0)
+        goto error;
+    }
+  }
+
+  credentials_counter++;
+
+  return credentials;
+
+error:
+  LOG(LOGS_ERR, "Could not set credentials : %s", gnutls_strerror(r));
+  if (credentials)
+    gnutls_certificate_free_credentials(credentials);
+  return NULL;
+}
+
+/* ================================================== */
+
+void
+NKSN_DestroyCertCredentials(void *credentials)
+{
+  gnutls_certificate_free_credentials(credentials);
+  credentials_counter--;
+  if (credentials_counter != 0)
+    return;
+
+  deinit_gnutls();
+}
+
+/* ================================================== */
+
+NKSN_Instance
+NKSN_CreateInstance(int server_mode, const char *name,
+                    NKSN_MessageHandler handler, void *handler_arg)
+{
+  NKSN_Instance inst;
+
+  inst = MallocNew(struct NKSN_Instance_Record);
+
+  inst->server = server_mode;
+  inst->name = Strdup(name);
+  inst->handler = handler;
+  inst->handler_arg = handler_arg;
+  /* Replace NULL arg with the session itself */
+  if (!inst->handler_arg)
+    inst->handler_arg = inst;
+
+  inst->state = KE_STOPPED;
+  inst->sock_fd = INVALID_SOCK_FD;
+  inst->tls_session = NULL;
+  inst->timeout_id = 0;
+
+  return inst;
+}
+
+/* ================================================== */
+
+void
+NKSN_DestroyInstance(NKSN_Instance inst)
+{
+  stop_session(inst);
+
+  Free(inst->name);
+  Free(inst);
+}
+
+/* ================================================== */
+
+int
+NKSN_StartSession(NKSN_Instance inst, int sock_fd, void *credentials, double timeout)
+{
+  assert(inst->state == KE_STOPPED);
+
+  inst->tls_session = create_tls_session(inst->server, sock_fd,
+                                         inst->server ? NULL : inst->name,
+                                         credentials, priority_cache);
+  if (!inst->tls_session)
+    return 0;
+
+  inst->sock_fd = sock_fd;
+  SCH_AddFileHandler(sock_fd, SCH_FILE_INPUT, read_write_socket, inst);
+
+  inst->timeout_id = SCH_AddTimeoutByDelay(timeout, session_timeout, inst);
+
+  reset_message(&inst->message);
+  inst->new_message = 0;
+  inst->ended_message = 0;
+
+  change_state(inst, inst->server ? KE_HANDSHAKE : KE_WAIT_CONNECT);
+
+  return 1;
+}
+
+/* ================================================== */
+
+void
+NKSN_BeginMessage(NKSN_Instance inst)
+{
+  reset_message(&inst->message);
+  inst->new_message = 1;
+}
+
+/* ================================================== */
+
+int
+NKSN_AddRecord(NKSN_Instance inst, int critical, int type, const void *body, int body_length)
+{
+  assert(inst->new_message && !inst->message.complete);
+  assert(type != NKE_RECORD_END_OF_MESSAGE);
+
+  return add_record(&inst->message, critical, type, body, body_length);
+}
+
+/* ================================================== */
+
+int
+NKSN_EndMessage(NKSN_Instance inst)
+{
+  assert(!inst->message.complete);
+
+  if (!add_record(&inst->message, 1, NKE_RECORD_END_OF_MESSAGE, NULL, 0))
+    return 0;
+
+  inst->message.complete = 1;
+
+  return 1;
+}
+
+/* ================================================== */
+
+int
+NKSN_GetRecord(NKSN_Instance inst, int *critical, int *type, int *body_length,
+               void *body, int buffer_length)
+{
+  int type2;
+
+  assert(inst->message.complete);
+
+  if (!get_record(&inst->message, critical, &type2, body_length, body, buffer_length))
+    return 0;
+
+  if (type2 == NKE_RECORD_END_OF_MESSAGE)
+    return 0;
+
+  if (type)
+    *type = type2;
+
+  return 1;
+}
+
+/* ================================================== */
+
+int
+NKSN_GetKeys(NKSN_Instance inst, SIV_Algorithm siv, NKE_Key *c2s, NKE_Key *s2c)
+{
+  c2s->length = SIV_GetKeyLength(siv);
+  s2c->length = SIV_GetKeyLength(siv);
+  assert(c2s->length <= sizeof (c2s->key));
+  assert(s2c->length <= sizeof (s2c->key));
+
+  if (gnutls_prf_rfc5705(inst->tls_session,
+                         sizeof (NKE_EXPORTER_LABEL) - 1, NKE_EXPORTER_LABEL,
+                         sizeof (NKE_EXPORTER_CONTEXT_C2S) - 1, NKE_EXPORTER_CONTEXT_C2S,
+                         c2s->length, (char *)c2s->key) < 0)
+    return 0;
+  if (gnutls_prf_rfc5705(inst->tls_session,
+                         sizeof (NKE_EXPORTER_LABEL) - 1, NKE_EXPORTER_LABEL,
+                         sizeof (NKE_EXPORTER_CONTEXT_S2C) - 1, NKE_EXPORTER_CONTEXT_S2C,
+                         s2c->length, (char *)s2c->key) < 0)
+    return 0;
+
+  return 1;
+}
+
+/* ================================================== */
+
+int
+NKSN_IsStopped(NKSN_Instance inst)
+{
+  return inst->state == KE_STOPPED;
+}
+
+/* ================================================== */
+
+void
+NKSN_StopSession(NKSN_Instance inst)
+{
+  stop_session(inst);
+}
--- a/nts_ke_session.h
+++ b/nts_ke_session.h
@@ -0,0 +1,83 @@
+/*
+  chronyd/chronyc - Programs for keeping computer clocks accurate.
+
+ **********************************************************************
+ * Copyright (C) Miroslav Lichvar  2020
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ * 
+ **********************************************************************
+
+  =======================================================================
+
+  Header file for the NTS-KE session
+  */
+
+#ifndef GOT_NTS_KE_SESSION_H
+#define GOT_NTS_KE_SESSION_H
+
+#include "nts_ke.h"
+#include "siv.h"
+
+typedef struct NKSN_Instance_Record *NKSN_Instance;
+
+/* Handler for received NTS-KE messages.  A non-zero return code stops
+   the session. */
+typedef int (*NKSN_MessageHandler)(void *arg);
+
+/* Get client or server credentials using certificates of trusted CAs,
+   or a server certificate and key.  The credentials may be shared between
+   different clients or servers. */
+extern void *NKSN_CreateCertCredentials(char *cert, char *key, char *trusted_certs);
+
+/* Destroy the credentials */
+extern void NKSN_DestroyCertCredentials(void *credentials);
+
+/* Create an instance */
+extern NKSN_Instance NKSN_CreateInstance(int server_mode, const char *name,
+                                         NKSN_MessageHandler handler, void *handler_arg);
+
+/* Destroy an instance */
+extern void NKSN_DestroyInstance(NKSN_Instance inst);
+
+/* Start a new NTS-KE session */
+extern int NKSN_StartSession(NKSN_Instance inst, int sock_fd, void *credentials,
+                             double timeout);
+
+/* Begin an NTS-KE message.  A request should be made right after starting
+   the session and response should be made in the message handler. */
+extern void NKSN_BeginMessage(NKSN_Instance inst);
+
+/* Add a record to the message */
+extern int NKSN_AddRecord(NKSN_Instance inst, int critical, int type,
+                          const void *body, int body_length);
+
+/* Terminate the message */
+extern int NKSN_EndMessage(NKSN_Instance inst);
+
+/* Get the next record from the received message.  This function should be
+   called from the message handler. */
+extern int NKSN_GetRecord(NKSN_Instance inst, int *critical, int *type, int *body_length,
+                          void *body, int buffer_length);
+
+/* Export NTS keys for a specified algorithm */
+extern int NKSN_GetKeys(NKSN_Instance inst, SIV_Algorithm siv, NKE_Key *c2s, NKE_Key *s2c);
+
+/* Check if the session has stopped */
+extern int NKSN_IsStopped(NKSN_Instance inst);
+
+/* Stop the session */
+extern void NKSN_StopSession(NKSN_Instance inst);
+
+#endif
--- a/nts_ntp.h
+++ b/nts_ntp.h
@@ -0,0 +1,41 @@
+/*
+  chronyd/chronyc - Programs for keeping computer clocks accurate.
+
+ **********************************************************************
+ * Copyright (C) Miroslav Lichvar  2020
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ * 
+ **********************************************************************
+
+  =======================================================================
+
+  Header file for the NTS-NTP protocol
+  */
+
+#ifndef GOT_NTS_NTP_H
+#define GOT_NTS_NTP_H
+
+#define NTP_EF_NTS_UNIQUE_IDENTIFIER    0x0104
+#define NTP_EF_NTS_COOKIE               0x0204
+#define NTP_EF_NTS_COOKIE_PLACEHOLDER   0x0304
+#define NTP_EF_NTS_AUTH_AND_EEF         0x0404
+
+#define NTP_KOD_NTS_NAK                 0x4e54534e
+
+#define NTS_MIN_UNIQ_ID_LENGTH          32
+#define NTS_MIN_UNPADDED_NONCE_LENGTH   16
+#define NTS_MAX_COOKIES                 8
+
+#endif
--- a/nts_ntp_auth.c
+++ b/nts_ntp_auth.c
@@ -0,0 +1,174 @@
+/*
+  chronyd/chronyc - Programs for keeping computer clocks accurate.
+
+ **********************************************************************
+ * Copyright (C) Miroslav Lichvar  2020
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ * 
+ **********************************************************************
+
+  =======================================================================
+
+  NTS Authenticator and Encrypted Extension Fields extension field
+  */
+
+#include "config.h"
+
+#include "sysincl.h"
+
+#include "nts_ntp_auth.h"
+
+#include "logging.h"
+#include "ntp_ext.h"
+#include "nts_ntp.h"
+#include "siv.h"
+#include "util.h"
+
+struct AuthHeader {
+  uint16_t nonce_length;
+  uint16_t ciphertext_length;
+};
+
+/* ================================================== */
+
+static int
+get_padding_length(int length)
+{
+  return length % 4U ? 4 - length % 4U : 0;
+}
+
+/* ================================================== */
+
+static int
+get_padded_length(int length)
+{
+  return length + get_padding_length(length);
+}
+
+/* ================================================== */
+
+int
+NNA_GenerateAuthEF(NTP_Packet *packet, NTP_PacketInfo *info, SIV_Instance siv,
+                   const unsigned char *nonce, int nonce_length,
+                   const unsigned char *plaintext, int plaintext_length,
+                   int min_ef_length)
+{
+  int auth_length, ciphertext_length, assoc_length;
+  int nonce_padding, ciphertext_padding, additional_padding;
+  unsigned char *ciphertext, *body;
+  struct AuthHeader *header;
+
+  assert(sizeof (*header) == 4);
+
+  if (nonce_length <= 0 || plaintext_length < 0) {
+    DEBUG_LOG("Invalid nonce/plaintext length");
+    return 0;
+  }
+
+  assoc_length = info->length;
+  ciphertext_length = SIV_GetTagLength(siv) + plaintext_length;
+  nonce_padding = get_padding_length(nonce_length);
+  ciphertext_padding = get_padding_length(ciphertext_length);
+  min_ef_length = get_padded_length(min_ef_length);
+
+  auth_length = sizeof (*header) + nonce_length + nonce_padding +
+                ciphertext_length + ciphertext_padding;
+  additional_padding = MAX(min_ef_length - auth_length - 4, 0);
+  additional_padding = MAX(NTS_MIN_UNPADDED_NONCE_LENGTH - nonce_length - nonce_padding,
+                           additional_padding);
+  auth_length += additional_padding;
+
+  if (!NEF_AddBlankField(packet, info, NTP_EF_NTS_AUTH_AND_EEF, auth_length,
+                         (void **)&header)) {
+    DEBUG_LOG("Could not add EF");
+    return 0;
+  }
+
+  header->nonce_length = htons(nonce_length);
+  header->ciphertext_length = htons(ciphertext_length);
+
+  body = (unsigned char *)(header + 1);
+  ciphertext = body + nonce_length + nonce_padding;
+
+  memcpy(body, nonce, nonce_length);
+  memset(body + nonce_length, 0, nonce_padding);
+
+  if (!SIV_Encrypt(siv, nonce, nonce_length, packet, assoc_length,
+                   plaintext, plaintext_length, ciphertext, ciphertext_length)) {
+    DEBUG_LOG("SIV encrypt failed");
+    return 0;
+  }
+
+  memset(ciphertext + ciphertext_length, 0, ciphertext_padding + additional_padding);
+
+  return 1;
+}
+
+/* ================================================== */
+
+int
+NNA_DecryptAuthEF(NTP_Packet *packet, NTP_PacketInfo *info, SIV_Instance siv, int ef_start,
+                  unsigned char *plaintext, int buffer_length, int *plaintext_length)
+{
+  unsigned int siv_tag_length, nonce_length, ciphertext_length;
+  unsigned char *nonce, *ciphertext;
+  int ef_type, ef_body_length;
+  void *ef_body;
+  struct AuthHeader *header;
+
+  if (!NEF_ParseField(packet, info->length, ef_start,
+                      NULL, &ef_type, &ef_body, &ef_body_length))
+    return 0;
+
+  if (ef_type != NTP_EF_NTS_AUTH_AND_EEF)
+    return 0;
+
+  header = ef_body;
+
+  nonce_length = ntohs(header->nonce_length);
+  ciphertext_length = ntohs(header->ciphertext_length);
+
+  if (get_padded_length(nonce_length) +
+      get_padded_length(ciphertext_length) > ef_body_length)
+    return 0;
+
+  nonce = (unsigned char *)(header + 1);
+  ciphertext = (unsigned char *)(header + 1) + get_padded_length(nonce_length);
+
+  siv_tag_length = SIV_GetTagLength(siv);
+
+  if (nonce_length < 1 ||
+      ciphertext_length < siv_tag_length ||
+      ciphertext_length - siv_tag_length > buffer_length) {
+    DEBUG_LOG("Unexpected nonce/ciphertext length");
+    return 0;
+  }
+
+  if (ef_body_length < sizeof (*header) +
+        NTS_MIN_UNPADDED_NONCE_LENGTH + get_padded_length(ciphertext_length)) {
+    DEBUG_LOG("Missing padding");
+    return 0;
+  }
+
+  *plaintext_length = ciphertext_length - siv_tag_length;
+
+  if (!SIV_Decrypt(siv, nonce, nonce_length, packet, info->length - ef_body_length - 4,
+                   ciphertext, ciphertext_length, plaintext, *plaintext_length)) {
+    DEBUG_LOG("SIV decrypt failed");
+    return 0;
+  }
+
+  return 1;
+}
--- a/nts_ntp_auth.h
+++ b/nts_ntp_auth.h
@@ -0,0 +1,43 @@
+/*
+  chronyd/chronyc - Programs for keeping computer clocks accurate.
+
+ **********************************************************************
+ * Copyright (C) Miroslav Lichvar  2020
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ * 
+ **********************************************************************
+
+  =======================================================================
+
+  Header for NTS Authenticator and Encrypted Extension Fields
+  extension field
+  */
+
+#ifndef GOT_NTS_NTP_AUTH_H
+#define GOT_NTS_NTP_AUTH_H
+
+#include "ntp.h"
+#include "siv.h"
+
+extern int NNA_GenerateAuthEF(NTP_Packet *packet, NTP_PacketInfo *info, SIV_Instance siv,
+                              const unsigned char *nonce, int nonce_length,
+                              const unsigned char *plaintext, int plaintext_length,
+                              int min_ef_length);
+
+extern int NNA_DecryptAuthEF(NTP_Packet *packet, NTP_PacketInfo *info, SIV_Instance siv,
+                             int ef_start, unsigned char *plaintext, int buffer_length,
+                             int *plaintext_length);
+
+#endif
--- a/nts_ntp_client.c
+++ b/nts_ntp_client.c
@@ -0,0 +1,441 @@
+/*
+  chronyd/chronyc - Programs for keeping computer clocks accurate.
+
+ **********************************************************************
+ * Copyright (C) Miroslav Lichvar  2020
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ * 
+ **********************************************************************
+
+  =======================================================================
+
+  Client NTS-NTP authentication
+  */
+
+#include "config.h"
+
+#include "sysincl.h"
+
+#include "nts_ntp_client.h"
+
+#include "conf.h"
+#include "logging.h"
+#include "memory.h"
+#include "ntp.h"
+#include "ntp_ext.h"
+#include "ntp_sources.h"
+#include "nts_ke_client.h"
+#include "nts_ntp.h"
+#include "nts_ntp_auth.h"
+#include "sched.h"
+#include "siv.h"
+#include "util.h"
+
+#define MAX_TOTAL_COOKIE_LENGTH (8 * 108)
+#define MIN_NKE_RETRY_INTERVAL 1000
+
+struct NNC_Instance_Record {
+  const IPSockAddr *ntp_address;
+  IPSockAddr nts_address;
+  char *name;
+  SIV_Instance siv_c2s;
+  SIV_Instance siv_s2c;
+  NKC_Instance nke;
+
+  double last_nke_attempt;
+  double last_nke_success;
+  NKE_Cookie cookies[NTS_MAX_COOKIES];
+  int num_cookies;
+  int cookie_index;
+  int nak_response;
+  int ok_response;
+  unsigned char nonce[NTS_MIN_UNPADDED_NONCE_LENGTH];
+  unsigned char uniq_id[NTS_MIN_UNIQ_ID_LENGTH];
+};
+
+/* ================================================== */
+
+static void
+reset_instance(NNC_Instance inst)
+{
+  inst->last_nke_attempt = -MIN_NKE_RETRY_INTERVAL;
+  inst->last_nke_success = 0.0;
+  inst->num_cookies = 0;
+  inst->cookie_index = 0;
+  inst->nak_response = 0;
+  inst->ok_response = 1;
+  memset(inst->nonce, 0, sizeof (inst->nonce));
+  memset(inst->uniq_id, 0, sizeof (inst->uniq_id));
+}
+
+/* ================================================== */
+
+NNC_Instance
+NNC_CreateInstance(IPSockAddr *nts_address, const char *name, const IPSockAddr *ntp_address)
+{
+  NNC_Instance inst;
+
+  inst = MallocNew(struct NNC_Instance_Record);
+
+  inst->ntp_address = ntp_address;
+  inst->nts_address = *nts_address;
+  inst->name = name ? Strdup(name) : NULL;
+  inst->siv_c2s = NULL;
+  inst->siv_s2c = NULL;
+  inst->nke = NULL;
+
+  reset_instance(inst);
+
+  return inst;
+}
+
+/* ================================================== */
+
+void
+NNC_DestroyInstance(NNC_Instance inst)
+{
+  if (inst->nke)
+    NKC_DestroyInstance(inst->nke);
+  if (inst->siv_c2s)
+    SIV_DestroyInstance(inst->siv_c2s);
+  if (inst->siv_s2c)
+    SIV_DestroyInstance(inst->siv_s2c);
+
+  Free(inst->name);
+  Free(inst);
+}
+
+/* ================================================== */
+
+static int
+is_nke_needed(NNC_Instance inst)
+{
+  /* Force NKE if a NAK was received since last valid auth */
+  if (inst->nak_response && !inst->ok_response && inst->num_cookies > 0) {
+    inst->num_cookies = 0;
+    DEBUG_LOG("Dropped cookies");
+  }
+
+  /* Force NKE if the keys encrypting the cookies are too old */
+  if (inst->num_cookies > 0 &&
+      SCH_GetLastEventMonoTime() - inst->last_nke_success > CNF_GetNtsRefresh())
+    inst->num_cookies = 0;
+
+  return inst->num_cookies == 0;
+}
+
+/* ================================================== */
+
+static int
+set_ntp_address(NNC_Instance inst, NTP_Remote_Address *negotiated_address)
+{
+  NTP_Remote_Address old_address, new_address;
+
+  old_address = *inst->ntp_address;
+  new_address = *negotiated_address;
+
+  if (new_address.ip_addr.family == IPADDR_UNSPEC)
+    new_address.ip_addr = old_address.ip_addr;
+  if (new_address.port == 0)
+    new_address.port = old_address.port;
+
+  if (UTI_CompareIPs(&old_address.ip_addr, &new_address.ip_addr, NULL) == 0 &&
+      old_address.port == new_address.port)
+    /* Nothing to do */
+    return 1;
+
+  if (NSR_UpdateSourceNtpAddress(&old_address, &new_address) != NSR_Success) {
+    LOG(LOGS_ERR, "Could not change %s to negotiated address %s",
+        UTI_IPToString(&old_address.ip_addr), UTI_IPToString(&new_address.ip_addr));
+    return 0;
+  }
+
+  return 1;
+}
+
+/* ================================================== */
+
+static int
+get_nke_data(NNC_Instance inst)
+{
+  NTP_Remote_Address ntp_address;
+  SIV_Algorithm siv;
+  NKE_Key c2s, s2c;
+  double now;
+  int got_data;
+
+  assert(is_nke_needed(inst));
+
+  now = SCH_GetLastEventMonoTime();
+
+  if (!inst->nke) {
+    if (now - inst->last_nke_attempt < MIN_NKE_RETRY_INTERVAL) {
+      DEBUG_LOG("Limiting NTS-KE request rate");
+      return 0;
+    }
+
+    if (!inst->name) {
+      LOG(LOGS_ERR, "Missing name of %s for NTS-KE",
+          UTI_IPToString(&inst->nts_address.ip_addr));
+      return 0;
+    }
+
+    inst->nke = NKC_CreateInstance(&inst->nts_address, inst->name);
+
+    if (!NKC_Start(inst->nke))
+      return 0;
+
+    inst->last_nke_attempt = now;
+  }
+
+  if (NKC_IsActive(inst->nke))
+    return 0;
+
+  got_data = NKC_GetNtsData(inst->nke, &siv, &c2s, &s2c,
+                            inst->cookies, &inst->num_cookies, NTS_MAX_COOKIES,
+                            &ntp_address);
+
+  NKC_DestroyInstance(inst->nke);
+  inst->nke = NULL;
+  
+  if (!got_data)
+    return 0;
+
+  if (!set_ntp_address(inst, &ntp_address)) {
+    inst->num_cookies = 0;
+    return 0;
+  }
+
+  inst->cookie_index = 0;
+
+  if (inst->siv_c2s)
+    SIV_DestroyInstance(inst->siv_c2s);
+  if (inst->siv_s2c)
+    SIV_DestroyInstance(inst->siv_s2c);
+
+  inst->siv_c2s = SIV_CreateInstance(siv);
+  inst->siv_s2c = SIV_CreateInstance(siv);
+
+  if (!inst->siv_c2s || !inst->siv_s2c ||
+      !SIV_SetKey(inst->siv_c2s, c2s.key, c2s.length) ||
+      !SIV_SetKey(inst->siv_s2c, s2c.key, s2c.length)) {
+    DEBUG_LOG("Could not initialise SIV");
+    inst->num_cookies = 0;
+    return 0;
+  }
+
+  inst->nak_response = 0;
+
+  inst->last_nke_success = now;
+
+  return 1;
+}
+
+/* ================================================== */
+
+int
+NNC_PrepareForAuth(NNC_Instance inst)
+{
+  if (is_nke_needed(inst)) {
+    if (!get_nke_data(inst))
+      return 0;
+  }
+
+  UTI_GetRandomBytes(&inst->uniq_id, sizeof (inst->uniq_id));
+  UTI_GetRandomBytes(&inst->nonce, sizeof (inst->nonce));
+
+  return 1;
+}
+
+/* ================================================== */
+
+int
+NNC_GenerateRequestAuth(NNC_Instance inst, NTP_Packet *packet,
+                        NTP_PacketInfo *info)
+{
+  NKE_Cookie *cookie;
+  int i, req_cookies;
+
+  if (inst->num_cookies == 0 || !inst->siv_c2s)
+    return 0;
+
+  if (info->mode != MODE_CLIENT)
+    return 0;
+
+  cookie = &inst->cookies[inst->cookie_index];
+  req_cookies = MIN(NTS_MAX_COOKIES - inst->num_cookies + 1,
+                    MAX_TOTAL_COOKIE_LENGTH / (cookie->length + 4));
+
+  if (!NEF_AddField(packet, info, NTP_EF_NTS_UNIQUE_IDENTIFIER,
+                    &inst->uniq_id, sizeof (inst->uniq_id)))
+    return 0;
+
+  if (!NEF_AddField(packet, info, NTP_EF_NTS_COOKIE,
+                    cookie->cookie, cookie->length))
+    return 0;
+
+  for (i = 0; i < req_cookies - 1; i++) {
+    if (!NEF_AddField(packet, info, NTP_EF_NTS_COOKIE_PLACEHOLDER,
+                      cookie->cookie, cookie->length))
+      return 0;
+  }
+
+  if (!NNA_GenerateAuthEF(packet, info, inst->siv_c2s, inst->nonce, sizeof (inst->nonce),
+                          (const unsigned char *)"", 0, NTP_MAX_V4_MAC_LENGTH + 4))
+    return 0;
+
+  inst->num_cookies--;
+  inst->cookie_index = (inst->cookie_index + 1) % NTS_MAX_COOKIES;
+  inst->ok_response = 0;
+
+  return 1;
+}
+
+/* ================================================== */
+
+static int
+extract_cookies(NNC_Instance inst, unsigned char *plaintext, int length)
+{
+  int ef_type, ef_body_length, ef_length, parsed, index, acceptable, saved;
+  void *ef_body;
+
+  acceptable = saved = 0;
+
+  for (parsed = 0; parsed < length; parsed += ef_length) {
+    if (!NEF_ParseSingleField(plaintext, length, parsed,
+                              &ef_length, &ef_type, &ef_body, &ef_body_length))
+      break;
+
+    if (ef_type != NTP_EF_NTS_COOKIE)
+      continue;
+
+    if (ef_length < NTP_MIN_EF_LENGTH || ef_body_length > sizeof (inst->cookies[0].cookie)) {
+      DEBUG_LOG("Unexpected cookie length %d", ef_body_length);
+      continue;
+    }
+
+    acceptable++;
+
+    if (inst->num_cookies >= NTS_MAX_COOKIES)
+      continue;
+
+    index = (inst->cookie_index + inst->num_cookies) % NTS_MAX_COOKIES;
+    memcpy(inst->cookies[index].cookie, ef_body, ef_body_length);
+    inst->cookies[index].length = ef_body_length;
+    inst->num_cookies++;
+
+    saved++;
+  }
+
+  DEBUG_LOG("Extracted %d cookies (saved %d)", acceptable, saved);
+
+  return acceptable > 0;
+}
+
+/* ================================================== */
+
+int
+NNC_CheckResponseAuth(NNC_Instance inst, NTP_Packet *packet,
+                      NTP_PacketInfo *info)
+{
+  int ef_type, ef_body_length, ef_length, parsed, plaintext_length;
+  int has_valid_uniq_id = 0, has_valid_auth = 0;
+  unsigned char plaintext[NTP_MAX_EXTENSIONS_LENGTH];
+  void *ef_body;
+
+  if (info->ext_fields == 0 || info->mode != MODE_SERVER)
+    return 0;
+
+  /* Accept only one response per request */
+  if (inst->ok_response)
+    return 0;
+
+  if (!inst->siv_s2c)
+    return 0;
+
+  for (parsed = NTP_HEADER_LENGTH; parsed < info->length; parsed += ef_length) {
+    if (!NEF_ParseField(packet, info->length, parsed,
+                        &ef_length, &ef_type, &ef_body, &ef_body_length))
+      break;
+
+    switch (ef_type) {
+      case NTP_EF_NTS_UNIQUE_IDENTIFIER:
+        if (ef_body_length != sizeof (inst->uniq_id) ||
+            memcmp(ef_body, inst->uniq_id, sizeof (inst->uniq_id)) != 0) {
+          DEBUG_LOG("Invalid uniq id");
+          return 0;
+        }
+        has_valid_uniq_id = 1;
+        break;
+      case NTP_EF_NTS_COOKIE:
+        DEBUG_LOG("Unencrypted cookie");
+        break;
+      case NTP_EF_NTS_AUTH_AND_EEF:
+        if (parsed + ef_length != info->length) {
+          DEBUG_LOG("Auth not last EF");
+          return 0;
+        }
+
+        if (!NNA_DecryptAuthEF(packet, info, inst->siv_s2c, parsed,
+                               plaintext, sizeof (plaintext), &plaintext_length))
+          return 0;
+
+        has_valid_auth = 1;
+        break;
+      default:
+        break;
+    }
+  }
+
+  if (!has_valid_uniq_id || !has_valid_auth) {
+    if (has_valid_uniq_id && packet->stratum == NTP_INVALID_STRATUM &&
+        ntohl(packet->reference_id) == NTP_KOD_NTS_NAK) {
+      DEBUG_LOG("NTS NAK");
+      inst->nak_response = 1;
+      return 0;
+    }
+
+    DEBUG_LOG("Missing NTS EF");
+    return 0;
+  }
+
+  if (!extract_cookies(inst, plaintext, plaintext_length))
+    return 0;
+
+  inst->ok_response = 1;
+
+  /* At this point we know the client interoperates with the server.  Allow a
+     new NTS-KE session to be started as soon as the cookies run out. */
+  inst->last_nke_attempt = -MIN_NKE_RETRY_INTERVAL;
+
+  return 1;
+}
+
+/* ================================================== */
+
+void
+NNC_ChangeAddress(NNC_Instance inst, IPAddr *address)
+{
+  if (inst->nke)
+    NKC_DestroyInstance(inst->nke);
+
+  inst->nke = NULL;
+  inst->num_cookies = 0;
+  inst->nts_address.ip_addr = *address;
+
+  reset_instance(inst);
+
+  DEBUG_LOG("NTS reset");
+}
--- a/nts_ntp_client.h
+++ b/nts_ntp_client.h
@@ -0,0 +1,46 @@
+/*
+  chronyd/chronyc - Programs for keeping computer clocks accurate.
+
+ **********************************************************************
+ * Copyright (C) Miroslav Lichvar  2020
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ * 
+ **********************************************************************
+
+  =======================================================================
+
+  Header file for client NTS-NTP authentication
+  */
+
+#ifndef GOT_NTS_NTP_CLIENT_H
+#define GOT_NTS_NTP_CLIENT_H
+
+#include "addressing.h"
+#include "ntp.h"
+
+typedef struct NNC_Instance_Record *NNC_Instance;
+
+extern NNC_Instance NNC_CreateInstance(IPSockAddr *nts_address, const char *name,
+                                                   const IPSockAddr *ntp_address);
+extern void NNC_DestroyInstance(NNC_Instance inst);
+extern int NNC_PrepareForAuth(NNC_Instance inst);
+extern int NNC_GenerateRequestAuth(NNC_Instance inst, NTP_Packet *packet,
+                                   NTP_PacketInfo *info);
+extern int NNC_CheckResponseAuth(NNC_Instance inst, NTP_Packet *packet,
+                                 NTP_PacketInfo *info);
+
+extern void NNC_ChangeAddress(NNC_Instance inst, IPAddr *address);
+
+#endif
--- a/nts_ntp_server.c
+++ b/nts_ntp_server.c
@@ -0,0 +1,253 @@
+/*
+  chronyd/chronyc - Programs for keeping computer clocks accurate.
+
+ **********************************************************************
+ * Copyright (C) Miroslav Lichvar  2020
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ * 
+ **********************************************************************
+
+  =======================================================================
+
+  Server NTS-NTP authentication
+  */
+
+#include "config.h"
+
+#include "sysincl.h"
+
+#include "nts_ntp_server.h"
+
+#include "conf.h"
+#include "logging.h"
+#include "memory.h"
+#include "ntp.h"
+#include "ntp_ext.h"
+#include "nts_ke_server.h"
+#include "nts_ntp.h"
+#include "nts_ntp_auth.h"
+#include "siv.h"
+#include "util.h"
+
+struct NtsServer {
+  SIV_Instance siv;
+  unsigned char nonce[NTS_MIN_UNPADDED_NONCE_LENGTH];
+  NKE_Cookie cookies[NTS_MAX_COOKIES];
+  int num_cookies;
+  NTP_int64 req_tx;
+};
+
+/* The server instance handling all requests */
+struct NtsServer *server;
+
+/* ================================================== */
+
+void
+NNS_Initialise(void)
+{
+  /* Create an NTS-NTP server instance only if NTS-KE server is enabled */
+  if (!CNF_GetNtsServerCertFile() || !CNF_GetNtsServerKeyFile()) {
+    server = NULL;
+    return;
+  }
+
+  server = Malloc(sizeof (struct NtsServer));
+  server->siv = SIV_CreateInstance(AEAD_AES_SIV_CMAC_256);
+}
+
+/* ================================================== */
+
+void
+NNS_Finalise(void)
+{
+  if (!server)
+    return;
+
+  SIV_DestroyInstance(server->siv);
+  Free(server);
+  server = NULL;
+}
+
+/* ================================================== */
+
+int
+NNS_CheckRequestAuth(NTP_Packet *packet, NTP_PacketInfo *info, uint32_t *kod)
+{
+  int ef_type, ef_body_length, ef_length, has_uniq_id = 0, has_auth = 0, has_cookie = 0;
+  int i, plaintext_length, parsed, requested_cookies, cookie_length = -1, auth_start = 0;
+  unsigned char plaintext[NTP_MAX_EXTENSIONS_LENGTH];
+  NKE_Cookie cookie;
+  NKE_Key c2s, s2c;
+  void *ef_body;
+
+  if (!server)
+    return 0;
+
+  *kod = 0;
+
+  server->num_cookies = 0;
+  server->req_tx = packet->transmit_ts;
+
+  if (info->ext_fields == 0 || info->mode != MODE_CLIENT)
+    return 0;
+
+  requested_cookies = 0;
+
+  for (parsed = NTP_HEADER_LENGTH; parsed < info->length; parsed += ef_length) {
+    if (!NEF_ParseField(packet, info->length, parsed,
+                        &ef_length, &ef_type, &ef_body, &ef_body_length))
+      break;
+
+    switch (ef_type) {
+      case NTP_EF_NTS_UNIQUE_IDENTIFIER:
+        has_uniq_id = 1;
+        break;
+      case NTP_EF_NTS_COOKIE:
+        if (has_cookie || ef_body_length > sizeof (cookie.cookie))
+          return 0;
+        cookie.length = ef_body_length;
+        memcpy(cookie.cookie, ef_body, ef_body_length);
+        has_cookie = 1;
+        /* Fall through */
+      case NTP_EF_NTS_COOKIE_PLACEHOLDER:
+        requested_cookies++;
+
+        if (cookie_length >= 0 && cookie_length != ef_body_length) {
+          DEBUG_LOG("Invalid cookie/placeholder length");
+          return 0;
+        }
+        cookie_length = ef_body_length;
+        break;
+      case NTP_EF_NTS_AUTH_AND_EEF:
+        auth_start = parsed;
+        has_auth = 1;
+        break;
+      default:
+        break;
+    }
+  }
+
+  if (!has_uniq_id || !has_cookie || !has_auth) {
+    DEBUG_LOG("Missing an NTS EF");
+    return 0;
+  }
+
+  if (!NKS_DecodeCookie(&cookie, &c2s, &s2c)) {
+    *kod = NTP_KOD_NTS_NAK;
+    return 0;
+  }
+
+  if (!SIV_SetKey(server->siv, c2s.key, c2s.length)) {
+    DEBUG_LOG("Could not set C2S key");
+    return 0;
+  }
+
+  if (!NNA_DecryptAuthEF(packet, info, server->siv, auth_start,
+                         plaintext, sizeof (plaintext), &plaintext_length)) {
+    *kod = NTP_KOD_NTS_NAK;
+    return 0;
+  }
+
+  for (parsed = 0; parsed < plaintext_length; parsed += ef_length) {
+    if (!NEF_ParseSingleField(plaintext, plaintext_length, parsed,
+                              &ef_length, &ef_type, &ef_body, &ef_body_length))
+      break;
+
+    switch (ef_type) {
+      case NTP_EF_NTS_COOKIE_PLACEHOLDER:
+        if (cookie_length != ef_body_length) {
+          DEBUG_LOG("Invalid cookie/placeholder length");
+          return 0;
+        }
+        requested_cookies++;
+        break;
+      default:
+        break;
+    }
+  }
+
+  if (!SIV_SetKey(server->siv, s2c.key, s2c.length)) {
+    DEBUG_LOG("Could not set S2C key");
+    return 0;
+  }
+
+  UTI_GetRandomBytes(server->nonce, sizeof (server->nonce));
+
+  server->num_cookies = MIN(NTS_MAX_COOKIES, requested_cookies);
+  for (i = 0; i < server->num_cookies; i++)
+    if (!NKS_GenerateCookie(&c2s, &s2c, &server->cookies[i]))
+      return 0;
+
+  return 1;
+}
+
+/* ================================================== */
+
+int
+NNS_GenerateResponseAuth(NTP_Packet *request, NTP_PacketInfo *req_info,
+                         NTP_Packet *response, NTP_PacketInfo *res_info,
+                         uint32_t kod)
+{
+  int i, ef_type, ef_body_length, ef_length, parsed;
+  void *ef_body;
+  unsigned char plaintext[NTP_MAX_EXTENSIONS_LENGTH];
+  int plaintext_length;
+
+  if (!server || req_info->mode != MODE_CLIENT || res_info->mode != MODE_SERVER)
+    return 0;
+
+  /* Make sure this is a response to the expected request */
+  if (UTI_CompareNtp64(&server->req_tx, &request->transmit_ts) != 0)
+    assert(0);
+
+  for (parsed = NTP_HEADER_LENGTH; parsed < req_info->length; parsed += ef_length) {
+    if (!NEF_ParseField(request, req_info->length, parsed,
+                        &ef_length, &ef_type, &ef_body, &ef_body_length))
+      break;
+
+    switch (ef_type) {
+      case NTP_EF_NTS_UNIQUE_IDENTIFIER:
+        /* Copy the ID from the request */
+        if (!NEF_AddField(response, res_info, ef_type, ef_body, ef_body_length))
+          return 0;
+      default:
+        break;
+    }
+  }
+
+  /* NTS NAK response does not have any other fields */
+  if (kod)
+    return 1;
+
+  for (i = 0, plaintext_length = 0; i < server->num_cookies; i++) {
+    if (!NEF_SetField(plaintext, sizeof (plaintext), plaintext_length,
+                      NTP_EF_NTS_COOKIE, &server->cookies[i].cookie,
+                      server->cookies[i].length, &ef_length))
+      return 0;
+
+    plaintext_length += ef_length;
+    assert(plaintext_length <= sizeof (plaintext));
+  }
+
+  server->num_cookies = 0;
+
+  if (!NNA_GenerateAuthEF(response, res_info, server->siv,
+                          server->nonce, sizeof (server->nonce),
+                          plaintext, plaintext_length,
+                          req_info->length - res_info->length))
+    return 0;
+
+  return 1;
+}
--- a/nts_ntp_server.h
+++ b/nts_ntp_server.h
@@ -0,0 +1,40 @@
+/*
+  chronyd/chronyc - Programs for keeping computer clocks accurate.
+
+ **********************************************************************
+ * Copyright (C) Miroslav Lichvar  2020
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ * 
+ **********************************************************************
+
+  =======================================================================
+
+  Header file for server NTS-NTP authentication
+  */
+
+#ifndef GOT_NTS_NTP_SERVER_H
+#define GOT_NTS_NTP_SERVER_H
+
+#include "ntp.h"
+
+extern void NNS_Initialise(void);
+extern void NNS_Finalise(void);
+
+extern int NNS_CheckRequestAuth(NTP_Packet *packet, NTP_PacketInfo *info, uint32_t *kod);
+extern int NNS_GenerateResponseAuth(NTP_Packet *request, NTP_PacketInfo *req_info,
+                                    NTP_Packet *response, NTP_PacketInfo *res_info,
+                                    uint32_t kod);
+
+#endif
--- a/pktlength.c
+++ b/pktlength.c
@@ -82,8 +82,8 @@ static const struct request_length request_lengths[] = {
  REQ_LENGTH_ENTRY(allow_deny, null),           /* CMDDENYALL */
  REQ_LENGTH_ENTRY(ac_check, null),             /* ACCHECK */
  REQ_LENGTH_ENTRY(ac_check, null),             /* CMDACCHECK */
-  REQ_LENGTH_ENTRY(ntp_source, null),           /* ADD_SERVER */
-  REQ_LENGTH_ENTRY(ntp_source, null),           /* ADD_PEER */
+  { 0, 0 },                                     /* ADD_SERVER */
+  { 0, 0 },                                     /* ADD_PEER */
  REQ_LENGTH_ENTRY(del_source, null),           /* DEL_SOURCE */
  REQ_LENGTH_ENTRY(null, null),                 /* WRITERTC */
  REQ_LENGTH_ENTRY(dfreq, null),                /* DFREQ */
@@ -113,6 +113,17 @@ static const struct request_length request_lengths[] = {
  REQ_LENGTH_ENTRY(client_accesses_by_index,
                   client_accesses_by_index),   /* CLIENT_ACCESSES_BY_INDEX2 */
  REQ_LENGTH_ENTRY(local, null),                /* LOCAL2 */
+  REQ_LENGTH_ENTRY(ntp_data, ntp_data),         /* NTP_DATA */
+  { 0, 0 },                                     /* ADD_SERVER2 */
+  { 0, 0 },                                     /* ADD_PEER2 */
+  { 0, 0 },                                     /* ADD_SERVER3 */
+  { 0, 0 },                                     /* ADD_PEER3 */
+  REQ_LENGTH_ENTRY(null, null),                 /* SHUTDOWN */
+  REQ_LENGTH_ENTRY(null, null),                 /* ONOFFLINE */
+  REQ_LENGTH_ENTRY(ntp_source, null),           /* ADD_SOURCE */
+  REQ_LENGTH_ENTRY(ntp_source_name,
+                   ntp_source_name),            /* NTP_SOURCE_NAME */
+  REQ_LENGTH_ENTRY(null, null),                 /* RESET */
 };

 static const uint16_t reply_lengths[] = {
@@ -120,18 +131,22 @@ static const uint16_t reply_lengths[] = {
  RPY_LENGTH_ENTRY(null),                       /* NULL */
  RPY_LENGTH_ENTRY(n_sources),                  /* N_SOURCES */
  RPY_LENGTH_ENTRY(source_data),                /* SOURCE_DATA */
-  RPY_LENGTH_ENTRY(manual_timestamp),           /* MANUAL_TIMESTAMP */
+  0,                                            /* MANUAL_TIMESTAMP */
  RPY_LENGTH_ENTRY(tracking),                   /* TRACKING */
  RPY_LENGTH_ENTRY(sourcestats),                /* SOURCESTATS */
  RPY_LENGTH_ENTRY(rtc),                        /* RTC */
  0,                                            /* SUBNETS_ACCESSED - not supported */
  0,                                            /* CLIENT_ACCESSES - not supported */
  0,                                            /* CLIENT_ACCESSES_BY_INDEX - not supported */
-  0,                                            /* MANUAL_LIST - variable length */
+  0,                                            /* MANUAL_LIST - not supported */
  RPY_LENGTH_ENTRY(activity),                   /* ACTIVITY */
  RPY_LENGTH_ENTRY(smoothing),                  /* SMOOTHING */
  RPY_LENGTH_ENTRY(server_stats),               /* SERVER_STATS */
  RPY_LENGTH_ENTRY(client_accesses_by_index),   /* CLIENT_ACCESSES_BY_INDEX2 */
+  RPY_LENGTH_ENTRY(ntp_data),                   /* NTP_DATA */
+  RPY_LENGTH_ENTRY(manual_timestamp),           /* MANUAL_TIMESTAMP2 */
+  RPY_LENGTH_ENTRY(manual_list),                /* MANUAL_LIST2 */
+  RPY_LENGTH_ENTRY(ntp_source_name),            /* NTP_SOURCE_NAME */
 };

 /* ================================================== */
@@ -188,21 +203,6 @@ PKL_ReplyLength(CMD_Reply *r)
  if (type < 1 || type >= N_REPLY_TYPES)
    return 0;

-  /* Length of MANUAL_LIST depends on number of samples stored in it */
-  if (type == RPY_MANUAL_LIST) {
-    uint32_t ns;
-
-    if (r->status != htons(STT_SUCCESS))
-      return offsetof(CMD_Reply, data);
-
-    ns = ntohl(r->data.manual_list.n_samples);
-    if (ns > MAX_MANUAL_LIST_SAMPLES)
-      return 0;
-
-    return offsetof(CMD_Reply, data.manual_list.samples) +
-           ns * sizeof (RPY_ManualListSample);
-  }
-
  return reply_lengths[type];
 }

--- a/privops.c
+++ b/privops.c
@@ -3,7 +3,7 @@

 **********************************************************************
 * Copyright (C) Bryan Christianson 2015
- * Copyright (C) Miroslav Lichvar  2016
+ * Copyright (C) Miroslav Lichvar  2017
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
@@ -33,6 +33,7 @@
 #include "nameserv.h"
 #include "logging.h"
 #include "privops.h"
+#include "socket.h"
 #include "util.h"

 #define OP_ADJUSTTIME     1024
@@ -40,6 +41,7 @@
 #define OP_SETTIME        1026
 #define OP_BINDSOCKET     1027
 #define OP_NAME2IPADDRESS 1028
+#define OP_RELOADDNS      1029
 #define OP_QUIT           1099

 union sockaddr_in46 {
@@ -157,7 +159,7 @@ res_fatal(PrvResponse *res, const char *fmt, ...)
 static int
 send_response(int fd, const PrvResponse *res)
 {
-  if (send(fd, res, sizeof (*res), 0) != sizeof (*res))
+  if (SCK_Send(fd, res, sizeof (*res), 0) != sizeof (*res))
    return 0;

  return 1;
@@ -169,37 +171,23 @@ send_response(int fd, const PrvResponse *res)
 static int
 receive_from_daemon(int fd, PrvRequest *req)
 {
-  struct msghdr msg;
-  struct cmsghdr *cmsg;
-  struct iovec iov;
-  char cmsgbuf[256];
+  SCK_Message message;

-  iov.iov_base = req;
-  iov.iov_len = sizeof (*req);
-
-  msg.msg_name = NULL;
-  msg.msg_namelen = 0;
-  msg.msg_iov = &iov;
-  msg.msg_iovlen = 1;
-  msg.msg_control = (void *)cmsgbuf;
-  msg.msg_controllen = sizeof (cmsgbuf);
-  msg.msg_flags = MSG_WAITALL;
-
-  /* read the data */
-  if (recvmsg(fd, &msg, 0) != sizeof (*req))
+  if (!SCK_ReceiveMessage(fd, &message, SCK_FLAG_MSG_DESCRIPTOR) ||
+      message.length != sizeof (*req))
    return 0;

+  memcpy(req, message.data, sizeof (*req));
+
  if (req->op == OP_BINDSOCKET) {
-    /* extract transferred descriptor */
-    req->data.bind_socket.sock = -1;
-    for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
-      if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS)
-        memcpy(&req->data.bind_socket.sock, CMSG_DATA(cmsg), sizeof (int));
-    }
+    req->data.bind_socket.sock = message.descriptor;

    /* return error if valid descriptor not found */
    if (req->data.bind_socket.sock < 0)
      return 0;
+  } else if (message.descriptor >= 0) {
+    SCK_CloseSocket(message.descriptor);
+    return 0;
  }

  return 1;
@@ -256,8 +244,7 @@ do_set_time(const ReqSetTime *req, PrvResponse *res)
 static void
 do_bind_socket(ReqBindSocket *req, PrvResponse *res)
 {
-  unsigned short port;
-  IPAddr ip;
+  IPSockAddr ip_saddr;
  int sock_fd;
  struct sockaddr *sa;
  socklen_t sa_len;
@@ -266,10 +253,11 @@ do_bind_socket(ReqBindSocket *req, PrvResponse *res)
  sa_len = req->sa_len;
  sock_fd = req->sock;

-  UTI_SockaddrToIPAndPort(sa, &ip, &port);
-  if (port && port != CNF_GetNTPPort()) {
-    close(sock_fd);
-    res_fatal(res, "Invalid port %d", port);
+  SCK_SockaddrToIPSockAddr(sa, sa_len, &ip_saddr);
+  if (ip_saddr.port != 0 && ip_saddr.port != CNF_GetNTPPort() &&
+      ip_saddr.port != CNF_GetAcquisitionPort()) {
+    SCK_CloseSocket(sock_fd);
+    res_fatal(res, "Invalid port %d", ip_saddr.port);
    return;
  }

@@ -278,7 +266,7 @@ do_bind_socket(ReqBindSocket *req, PrvResponse *res)
    res->res_errno = errno;

  /* sock is still open on daemon side, but we're done with it in the helper */
-  close(sock_fd);
+  SCK_CloseSocket(sock_fd);
 }
 #endif

@@ -293,8 +281,6 @@ do_name_to_ipaddress(ReqName2IPAddress *req, PrvResponse *res)
  /* make sure the string is terminated */
  req->name[sizeof (req->name) - 1] = '\0';

-  DNS_Reload();
-
  res->rc = DNS_Name2IPAddress(req->name, res->data.name_to_ipaddress.addresses,
                               DNS_MAX_ADDRESSES);
 }
@@ -302,6 +288,19 @@ do_name_to_ipaddress(ReqName2IPAddress *req, PrvResponse *res)

 /* ======================================================================= */

+/* HELPER - perform DNS_Reload() */
+
+#ifdef PRIVOPS_RELOADDNS
+static void
+do_reload_dns(PrvResponse *res)
+{
+  DNS_Reload();
+  res->rc = 0;
+}
+#endif
+
+/* ======================================================================= */
+
 /* HELPER - main loop - action requests from the daemon */

 static void
@@ -343,6 +342,11 @@ helper_main(int fd)
      case OP_NAME2IPADDRESS:
        do_name_to_ipaddress(&req.data.name_to_ipaddress, &res);
        break;
+#endif
+#ifdef PRIVOPS_RELOADDNS
+      case OP_RELOADDNS:
+        do_reload_dns(&res);
+        break;
 #endif
      case OP_QUIT:
        quit = 1;
@@ -356,7 +360,7 @@ helper_main(int fd)
    send_response(fd, &res);
  }

-  close(fd);
+  SCK_CloseSocket(fd);
  exit(0);
 }

@@ -369,16 +373,16 @@ receive_response(PrvResponse *res)
 {
  int resp_len;

-  resp_len = recv(helper_fd, res, sizeof (*res), 0);
+  resp_len = SCK_Receive(helper_fd, res, sizeof (*res), 0);
  if (resp_len < 0)
-    LOG_FATAL(LOGF_PrivOps, "Could not read from helper : %s", strerror(errno));
+    LOG_FATAL("Could not read from helper : %s", strerror(errno));
  if (resp_len != sizeof (*res))
-    LOG_FATAL(LOGF_PrivOps, "Invalid helper response");
+    LOG_FATAL("Invalid helper response");

  if (res->fatal_error)
-    LOG_FATAL(LOGF_PrivOps, "Error in helper : %s", res->data.fatal_msg.msg);
+    LOG_FATAL("Error in helper : %s", res->data.fatal_msg.msg);

-  DEBUG_LOG(LOGF_PrivOps, "Received response rc=%d", res->rc);
+  DEBUG_LOG("Received response rc=%d", res->rc);

  /* if operation failed in the helper, set errno so daemon can print log message */
  if (res->res_errno)
@@ -392,47 +396,28 @@ receive_response(PrvResponse *res)
 static void
 send_request(PrvRequest *req)
 {
-  struct msghdr msg;
-  struct iovec iov;
-  char cmsgbuf[256];
+  SCK_Message message;
+  int flags;

-  iov.iov_base = req;
-  iov.iov_len = sizeof (*req);
+  SCK_InitMessage(&message, SCK_ADDR_UNSPEC);

-  msg.msg_name = NULL;
-  msg.msg_namelen = 0;
-  msg.msg_iov = &iov;
-  msg.msg_iovlen = 1;
-  msg.msg_control = NULL;
-  msg.msg_controllen = 0;
-  msg.msg_flags = 0;
+  message.data = req;
+  message.length = sizeof (*req);
+  flags = 0;

  if (req->op == OP_BINDSOCKET) {
    /* send file descriptor as a control message */
-    struct cmsghdr *cmsg;
-    int *ptr_send_fd;
-
-    msg.msg_control = cmsgbuf;
-    msg.msg_controllen = CMSG_SPACE(sizeof (int));
-
-    cmsg = CMSG_FIRSTHDR(&msg);
-    memset(cmsg, 0, CMSG_SPACE(sizeof (int)));
-
-    cmsg->cmsg_level = SOL_SOCKET;
-    cmsg->cmsg_type = SCM_RIGHTS;
-    cmsg->cmsg_len = CMSG_LEN(sizeof (int));
-
-    ptr_send_fd = (int *)CMSG_DATA(cmsg);
-    *ptr_send_fd = req->data.bind_socket.sock;
+    message.descriptor = req->data.bind_socket.sock;
+    flags |= SCK_FLAG_MSG_DESCRIPTOR;
  }

-  if (sendmsg(helper_fd, &msg, 0) < 0) {
+  if (!SCK_SendMessage(helper_fd, &message, flags)) {
    /* don't try to send another request from exit() */
    helper_fd = -1;
-    LOG_FATAL(LOGF_PrivOps, "Could not send to helper : %s", strerror(errno));
+    LOG_FATAL("Could not send to helper : %s", strerror(errno));
  }

-  DEBUG_LOG(LOGF_PrivOps, "Sent request op=%d", req->op);
+  DEBUG_LOG("Sent request op=%d", req->op);
 }

 /* ======================================================================= */
@@ -556,13 +541,14 @@ PRV_SetTime(const struct timeval *tp, const struct timezone *tzp)
 int
 PRV_BindSocket(int sock, struct sockaddr *address, socklen_t address_len)
 {
+  IPSockAddr ip_saddr;
  PrvRequest req;
  PrvResponse res;
-  IPAddr ip;
-  unsigned short port;

-  UTI_SockaddrToIPAndPort(address, &ip, &port);
-  assert(!port || port == CNF_GetNTPPort());
+  SCK_SockaddrToIPSockAddr(address, address_len, &ip_saddr);
+  if (ip_saddr.port != 0 && ip_saddr.port != CNF_GetNTPPort() &&
+      ip_saddr.port != CNF_GetAcquisitionPort())
+    assert(0);

  if (!have_helper())
    return bind(sock, address, address_len);
@@ -571,6 +557,7 @@ PRV_BindSocket(int sock, struct sockaddr *address, socklen_t address_len)
  req.op = OP_BINDSOCKET;
  req.data.bind_socket.sock = sock;
  req.data.bind_socket.sa_len = address_len;
+  assert(address_len <= sizeof (req.data.bind_socket.sa));
  memcpy(&req.data.bind_socket.sa.u, address, address_len);

  submit_request(&req, &res);
@@ -598,7 +585,6 @@ PRV_Name2IPAddress(const char *name, IPAddr *ip_addrs, int max_addrs)
  req.op = OP_NAME2IPADDRESS;
  if (snprintf(req.data.name_to_ipaddress.name, sizeof (req.data.name_to_ipaddress.name),
               "%s", name) >= sizeof (req.data.name_to_ipaddress.name)) {
-    DEBUG_LOG(LOGF_PrivOps, "Name too long");
    return DNS_Failure;
  }

@@ -613,6 +599,30 @@ PRV_Name2IPAddress(const char *name, IPAddr *ip_addrs, int max_addrs)

 /* ======================================================================= */

+/* DAEMON - request res_init() */
+
+#ifdef PRIVOPS_RELOADDNS
+void
+PRV_ReloadDNS(void)
+{
+  PrvRequest req;
+  PrvResponse res;
+
+  if (!have_helper()) {
+    DNS_Reload();
+    return;
+  }
+
+  memset(&req, 0, sizeof (req));
+  req.op = OP_RELOADDNS;
+
+  submit_request(&req, &res);
+  assert(!res.rc);
+}
+#endif
+
+/* ======================================================================= */
+
 void
 PRV_Initialise(void)
 {
@@ -628,44 +638,37 @@ void
 PRV_StartHelper(void)
 {
  pid_t pid;
-  int fd, sock_pair[2];
+  int fd, sock_fd1, sock_fd2;

  if (have_helper())
-    LOG_FATAL(LOGF_PrivOps, "Helper already running");
+    LOG_FATAL("Helper already running");

-  if (
-#ifdef SOCK_SEQPACKET
-      socketpair(AF_UNIX, SOCK_SEQPACKET, 0, sock_pair) &&
-#endif
-      socketpair(AF_UNIX, SOCK_DGRAM, 0, sock_pair))
-    LOG_FATAL(LOGF_PrivOps, "socketpair() failed : %s", strerror(errno));
-
-  UTI_FdSetCloexec(sock_pair[0]);
-  UTI_FdSetCloexec(sock_pair[1]);
+  sock_fd1 = SCK_OpenUnixSocketPair(SCK_FLAG_BLOCK, &sock_fd2);

  pid = fork();
  if (pid < 0)
-    LOG_FATAL(LOGF_PrivOps, "fork() failed : %s", strerror(errno));
+    LOG_FATAL("fork() failed : %s", strerror(errno));

  if (pid == 0) {
    /* child process */
-    close(sock_pair[0]);
+    SCK_CloseSocket(sock_fd1);

-    /* close other descriptors inherited from the parent process */
-    for (fd = 0; fd < 1024; fd++) {
-      if (fd != sock_pair[1])
+    /* close other descriptors inherited from the parent process, except
+       stdin, stdout, and stderr */
+    for (fd = STDERR_FILENO + 1; fd < 1024; fd++) {
+      if (fd != sock_fd2)
        close(fd);
    }

    /* ignore signals, the process will exit on OP_QUIT request */
-    UTI_SetQuitSignalsHandler(SIG_IGN);
+    UTI_SetQuitSignalsHandler(SIG_IGN, 1);

-    helper_main(sock_pair[1]);
+    helper_main(sock_fd2);

  } else {
    /* parent process */
-    close(sock_pair[1]);
-    helper_fd = sock_pair[0];
+    SCK_CloseSocket(sock_fd2);
+    helper_fd = sock_fd1;
    helper_pid = pid;

    /* stop the helper even when not exiting cleanly from the main function */
--- a/privops.h
+++ b/privops.h
@@ -58,6 +58,12 @@ int PRV_Name2IPAddress(const char *name, IPAddr *ip_addrs, int max_addrs);
 #define PRV_Name2IPAddress DNS_Name2IPAddress
 #endif

+#ifdef PRIVOPS_RELOADDNS
+void PRV_ReloadDNS(void);
+#else
+#define PRV_ReloadDNS DNS_Reload
+#endif
+
 #ifdef PRIVOPS_HELPER
 void PRV_Initialise(void);
 void PRV_StartHelper(void);
--- a/refclock.c
+++ b/refclock.c
@@ -2,7 +2,7 @@
  chronyd/chronyc - Programs for keeping computer clocks accurate.

 **********************************************************************
- * Copyright (C) Miroslav Lichvar  2009-2011, 2013-2014
+ * Copyright (C) Miroslav Lichvar  2009-2011, 2013-2014, 2016-2019
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
@@ -37,6 +37,7 @@
 #include "sources.h"
 #include "logging.h"
 #include "regress.h"
+#include "samplefilt.h"
 #include "sched.h"

 /* list of refclock drivers */
@@ -48,7 +49,7 @@ extern RefclockDriver RCL_PHC_driver;
 struct FilterSample {
  double offset;
  double dispersion;
-  struct timeval sample_time;
+  struct timespec sample_time;
 };

 struct MedianFilter {
@@ -75,14 +76,19 @@ struct RCL_Instance_Record {
  int driver_polled;
  int poll;
  int leap_status;
+  int pps_forced;
  int pps_rate;
  int pps_active;
-  struct MedianFilter filter;
+  int max_lock_age;
+  int stratum;
+  int tai;
  uint32_t ref_id;
  uint32_t lock_ref;
  double offset;
  double delay;
  double precision;
+  double pulse_width;
+  SPF_Instance filter;
  SCH_TimeoutID timeout_id;
  SRC_Instance source;
 };
@@ -92,25 +98,13 @@ static ARR_Instance refclocks;

 static LOG_FileID logfileid;

-static int valid_sample_time(RCL_Instance instance, struct timeval *raw, struct timeval *cooked);
-static int pps_stratum(RCL_Instance instance, struct timeval *tv);
+static int valid_sample_time(RCL_Instance instance, struct timespec *sample_time);
+static int pps_stratum(RCL_Instance instance, struct timespec *ts);
 static void poll_timeout(void *arg);
-static void slew_samples(struct timeval *raw, struct timeval *cooked, double dfreq,
+static void slew_samples(struct timespec *raw, struct timespec *cooked, double dfreq,
             double doffset, LCL_ChangeType change_type, void *anything);
 static void add_dispersion(double dispersion, void *anything);
-static void log_sample(RCL_Instance instance, struct timeval *sample_time, int filtered, int pulse, double raw_offset, double cooked_offset, double dispersion);
-
-static void filter_init(struct MedianFilter *filter, int length, double max_dispersion);
-static void filter_fini(struct MedianFilter *filter);
-static void filter_reset(struct MedianFilter *filter);
-static double filter_get_avg_sample_dispersion(struct MedianFilter *filter);
-static void filter_add_sample(struct MedianFilter *filter, struct timeval *sample_time, double offset, double dispersion);
-static int filter_get_last_sample(struct MedianFilter *filter, struct timeval *sample_time, double *offset, double *dispersion);
-static int filter_get_samples(struct MedianFilter *filter);
-static int filter_select_samples(struct MedianFilter *filter);
-static int filter_get_sample(struct MedianFilter *filter, struct timeval *sample_time, double *offset, double *dispersion);
-static void filter_slew_samples(struct MedianFilter *filter, struct timeval *when, double dfreq, double doffset);
-static void filter_add_dispersion(struct MedianFilter *filter, double dispersion);
+static void log_sample(RCL_Instance instance, struct timespec *sample_time, int filtered, int pulse, double raw_offset, double cooked_offset, double dispersion);

 static RCL_Instance
 get_refclock(unsigned int index)
@@ -146,7 +140,7 @@ RCL_Finalise(void)
    if (inst->driver->fini)
      inst->driver->fini(inst);

-    filter_fini(&inst->filter);
+    SPF_DestroyInstance(inst->filter);
    Free(inst->driver_parameter);
    SRC_DestroyInstance(inst->source);
    Free(inst);
@@ -163,7 +157,6 @@ RCL_Finalise(void)
 int
 RCL_AddRefclock(RefclockParameters *params)
 {
-  int pps_source = 0;
  RCL_Instance inst;

  inst = MallocNew(struct RCL_Instance_Record);
@@ -171,27 +164,21 @@ RCL_AddRefclock(RefclockParameters *params)

  if (strcmp(params->driver_name, "SHM") == 0) {
    inst->driver = &RCL_SHM_driver;
-    inst->precision = 1e-6;
  } else if (strcmp(params->driver_name, "SOCK") == 0) {
    inst->driver = &RCL_SOCK_driver;
-    inst->precision = 1e-9;
-    pps_source = 1;
  } else if (strcmp(params->driver_name, "PPS") == 0) {
    inst->driver = &RCL_PPS_driver;
-    inst->precision = 1e-9;
-    pps_source = 1;
  } else if (strcmp(params->driver_name, "PHC") == 0) {
    inst->driver = &RCL_PHC_driver;
-    inst->precision = 1e-9;
  } else {
-    LOG_FATAL(LOGF_Refclock, "unknown refclock driver %s", params->driver_name);
-    return 0;
+    LOG_FATAL("unknown refclock driver %s", params->driver_name);
  }

-  if (!inst->driver->init && !inst->driver->poll) {
-    LOG_FATAL(LOGF_Refclock, "refclock driver %s is not compiled in", params->driver_name);
-    return 0;
-  }
+  if (!inst->driver->init && !inst->driver->poll)
+    LOG_FATAL("refclock driver %s is not compiled in", params->driver_name);
+
+  if (params->tai && !CNF_GetLeapSecTimezone())
+    LOG_FATAL("refclock tai option requires leapsectz");

  inst->data = NULL;
  inst->driver_parameter = params->driver_parameter;
@@ -200,13 +187,18 @@ RCL_AddRefclock(RefclockParameters *params)
  inst->poll = params->poll;
  inst->driver_polled = 0;
  inst->leap_status = LEAP_Normal;
+  inst->pps_forced = params->pps_forced;
  inst->pps_rate = params->pps_rate;
  inst->pps_active = 0;
+  inst->max_lock_age = params->max_lock_age;
+  inst->stratum = params->stratum;
+  inst->tai = params->tai;
  inst->lock_ref = params->lock_ref_id;
  inst->offset = params->offset;
  inst->delay = params->delay;
-  if (params->precision > 0.0)
-    inst->precision = params->precision;
+  inst->precision = LCL_GetSysPrecisionAsQuantum();
+  inst->precision = MAX(inst->precision, params->precision);
+  inst->pulse_width = params->pulse_width;
  inst->timeout_id = -1;
  inst->source = NULL;

@@ -219,12 +211,8 @@ RCL_AddRefclock(RefclockParameters *params)
        inst->driver_parameter[i] = '\0';
  }

-  if (pps_source) {
-    if (inst->pps_rate < 1)
-      inst->pps_rate = 1;
-  } else {
-    inst->pps_rate = 0;
-  }
+  if (inst->pps_rate < 1)
+    inst->pps_rate = 1;

  if (params->ref_id)
    inst->ref_id = params->ref_id;
@@ -249,25 +237,26 @@ RCL_AddRefclock(RefclockParameters *params)
    max_samples = 1 << (inst->poll - inst->driver_poll);
    if (max_samples < params->filter_length) {
      if (max_samples < 4) {
-        LOG(LOGS_WARN, LOGF_Refclock, "Setting filter length for %s to %d",
+        LOG(LOGS_WARN, "Setting filter length for %s to %d",
            UTI_RefidToString(inst->ref_id), max_samples);
      }
      params->filter_length = max_samples;
    }
  }

-  if (inst->driver->init)
-    if (!inst->driver->init(inst)) {
-      LOG_FATAL(LOGF_Refclock, "refclock %s initialisation failed", params->driver_name);
-      return 0;
-    }
+  if (inst->driver->init && !inst->driver->init(inst))
+    LOG_FATAL("refclock %s initialisation failed", params->driver_name);

-  filter_init(&inst->filter, params->filter_length, params->max_dispersion);
+  /* Require the filter to have at least 4 samples to produce a filtered
+     sample, or be full for shorter lengths, and combine 60% of samples
+     closest to the median */
+  inst->filter = SPF_CreateInstance(MIN(params->filter_length, 4), params->filter_length,
+                                    params->max_dispersion, 0.6);

  inst->source = SRC_CreateNewInstance(inst->ref_id, SRC_REFCLOCK, params->sel_options, NULL,
-                                       params->min_samples, params->max_samples);
+                                       params->min_samples, params->max_samples, 0.0, 0.0);

-  DEBUG_LOG(LOGF_Refclock, "refclock %s refid=%s poll=%d dpoll=%d filter=%d",
+  DEBUG_LOG("refclock %s refid=%s poll=%d dpoll=%d filter=%d",
      params->driver_name, UTI_RefidToString(inst->ref_id),
      inst->poll, inst->driver_poll, params->filter_length);

@@ -300,7 +289,7 @@ RCL_StartRefclocks(void)
 }

 void
-RCL_ReportSource(RPT_SourceReport *report, struct timeval *now)
+RCL_ReportSource(RPT_SourceReport *report, struct timespec *now)
 {
  unsigned int i;
  uint32_t ref_id;
@@ -336,44 +325,122 @@ RCL_GetDriverParameter(RCL_Instance instance)
  return instance->driver_parameter;
 }

+static char *
+get_next_driver_option(RCL_Instance instance, char *option)
+{
+  if (option == NULL)
+    option = instance->driver_parameter;
+
+  option += strlen(option) + 1;
+
+  if (option >= instance->driver_parameter + instance->driver_parameter_length)
+    return NULL;
+
+  return option;
+}
+
+void
+RCL_CheckDriverOptions(RCL_Instance instance, const char **options)
+{
+  char *option;
+  int i, len;
+
+  for (option = get_next_driver_option(instance, NULL);
+       option;
+       option = get_next_driver_option(instance, option)) {
+    for (i = 0; options && options[i]; i++) {
+      len = strlen(options[i]);
+      if (!strncmp(options[i], option, len) &&
+          (option[len] == '=' || option[len] == '\0'))
+        break;
+    }
+
+    if (!options || !options[i])
+      LOG_FATAL("Invalid refclock driver option %s", option);
+  }
+}
+
 char *
 RCL_GetDriverOption(RCL_Instance instance, char *name)
 {
-  char *s, *e;
-  int n;
+  char *option;
+  int len;

-  s = instance->driver_parameter;
-  e = s + instance->driver_parameter_length;
-  n = strlen(name);
+  len = strlen(name);

-  while (1) {
-    s += strlen(s) + 1;
-    if (s >= e)
-      break;
-    if (!strncmp(name, s, n)) {
-      if (s[n] == '=')
-        return s + n + 1;
-      if (s[n] == '\0')
-        return s + n;
+  for (option = get_next_driver_option(instance, NULL);
+       option;
+       option = get_next_driver_option(instance, option)) {
+    if (!strncmp(name, option, len)) {
+      if (option[len] == '=')
+        return option + len + 1;
+      if (option[len] == '\0')
+        return option + len;
    }
  }

  return NULL;
 }

+static int
+convert_tai_offset(struct timespec *sample_time, double *offset)
+{
+  struct timespec tai_ts, utc_ts;
+  int tai_offset;
+
+  /* Get approximate TAI-UTC offset for the reference time in TAI */
+  UTI_AddDoubleToTimespec(sample_time, *offset, &tai_ts);
+  tai_offset = REF_GetTaiOffset(&tai_ts);
+
+  /* Get TAI-UTC offset for the reference time in UTC +/- 1 second */
+  UTI_AddDoubleToTimespec(&tai_ts, -tai_offset, &utc_ts);
+  tai_offset = REF_GetTaiOffset(&utc_ts);
+
+  if (!tai_offset)
+    return 0;
+
+  *offset -= tai_offset;
+
+  return 1;
+}
+
+static int
+accumulate_sample(RCL_Instance instance, struct timespec *sample_time, double offset, double dispersion)
+{
+  NTP_Sample sample;
+
+  sample.time = *sample_time;
+  sample.offset = offset;
+  sample.peer_delay = instance->delay;
+  sample.root_delay = instance->delay;
+  sample.peer_dispersion = dispersion;
+  sample.root_dispersion = dispersion;
+
+  /* Handle special case when PPS is used with the local reference */
+  if (instance->pps_active && instance->lock_ref == -1)
+    sample.stratum = pps_stratum(instance, &sample.time);
+  else
+    sample.stratum = instance->stratum;
+
+  return SPF_AccumulateSample(instance->filter, &sample);
+}
+
 int
-RCL_AddSample(RCL_Instance instance, struct timeval *sample_time, double offset, int leap)
+RCL_AddSample(RCL_Instance instance, struct timespec *sample_time, double offset, int leap)
 {
  double correction, dispersion;
-  struct timeval cooked_time;
+  struct timespec cooked_time;
+
+  if (instance->pps_forced)
+    return RCL_AddPulse(instance, sample_time, -offset);

  LCL_GetOffsetCorrection(sample_time, &correction, &dispersion);
-  UTI_AddDoubleToTimeval(sample_time, correction, &cooked_time);
+  UTI_AddDoubleToTimespec(sample_time, correction, &cooked_time);
  dispersion += instance->precision;

  /* Make sure the timestamp and offset provided by the driver are sane */
  if (!UTI_IsTimeOffsetSane(sample_time, offset) ||
-      !valid_sample_time(instance, sample_time, &cooked_time))
+      !valid_sample_time(instance, &cooked_time))
    return 0;

  switch (leap) {
@@ -383,11 +450,19 @@ RCL_AddSample(RCL_Instance instance, struct timeval *sample_time, double offset,
      instance->leap_status = leap;
      break;
    default:
-      DEBUG_LOG(LOGF_Refclock, "refclock sample ignored bad leap %d", leap);
+      DEBUG_LOG("refclock sample ignored bad leap %d", leap);
      return 0;
  }

-  filter_add_sample(&instance->filter, &cooked_time, offset - correction + instance->offset, dispersion);
+  if (instance->tai && !convert_tai_offset(sample_time, &offset)) {
+    DEBUG_LOG("refclock sample ignored unknown TAI offset");
+    return 0;
+  }
+
+  if (!accumulate_sample(instance, &cooked_time,
+                         offset - correction + instance->offset, dispersion))
+    return 0;
+
  instance->pps_active = 0;

  log_sample(instance, &cooked_time, 0, 0, offset, offset - correction + instance->offset, dispersion);
@@ -400,26 +475,59 @@ RCL_AddSample(RCL_Instance instance, struct timeval *sample_time, double offset,
 }

 int
-RCL_AddPulse(RCL_Instance instance, struct timeval *pulse_time, double second)
+RCL_AddPulse(RCL_Instance instance, struct timespec *pulse_time, double second)
 {
-  double correction, dispersion, offset;
-  struct timeval cooked_time;
+  double correction, dispersion;
+  struct timespec cooked_time;
+
+  LCL_GetOffsetCorrection(pulse_time, &correction, &dispersion);
+  UTI_AddDoubleToTimespec(pulse_time, correction, &cooked_time);
+  second += correction;
+
+  if (!UTI_IsTimeOffsetSane(pulse_time, 0.0))
+    return 0;
+
+  return RCL_AddCookedPulse(instance, &cooked_time, second, dispersion, correction);
+}
+
+static int
+check_pulse_edge(RCL_Instance instance, double offset, double distance)
+{
+  double max_error;
+
+  if (instance->pulse_width <= 0.0)
+    return 1;
+
+  max_error = 1.0 / instance->pps_rate - instance->pulse_width;
+  max_error = MIN(instance->pulse_width, max_error);
+  max_error *= 0.5;
+
+  if (fabs(offset) > max_error || distance > max_error) {
+      DEBUG_LOG("refclock pulse ignored offset=%.9f distance=%.9f max_error=%.9f",
+                offset, distance, max_error);
+      return 0;
+  }
+
+  return 1;
+}
+
+int
+RCL_AddCookedPulse(RCL_Instance instance, struct timespec *cooked_time,
+                   double second, double dispersion, double raw_correction)
+{
+  double offset;
  int rate;
  NTP_Leap leap;

-  leap = LEAP_Normal;
-  LCL_GetOffsetCorrection(pulse_time, &correction, &dispersion);
-  UTI_AddDoubleToTimeval(pulse_time, correction, &cooked_time);
-  dispersion += instance->precision;
-
-  if (!UTI_IsTimeOffsetSane(pulse_time, 0.0) ||
-      !valid_sample_time(instance, pulse_time, &cooked_time))
+  if (!UTI_IsTimeOffsetSane(cooked_time, second) ||
+      !valid_sample_time(instance, cooked_time))
    return 0;

+  leap = LEAP_Normal;
+  dispersion += instance->precision;
  rate = instance->pps_rate;
-  assert(rate > 0);

-  offset = -second - correction + instance->offset;
+  offset = -second + instance->offset;

  /* Adjust the offset to [-0.5/rate, 0.5/rate) interval */
  offset -= (long)(offset * rate) / (double)rate;
@@ -430,46 +538,49 @@ RCL_AddPulse(RCL_Instance instance, struct timeval *pulse_time, double second)

  if (instance->lock_ref != -1) {
    RCL_Instance lock_refclock;
-    struct timeval ref_sample_time;
-    double sample_diff, ref_offset, ref_dispersion, shift;
+    NTP_Sample ref_sample;
+    double sample_diff, shift;

    lock_refclock = get_refclock(instance->lock_ref);

-    if (!filter_get_last_sample(&lock_refclock->filter,
-          &ref_sample_time, &ref_offset, &ref_dispersion)) {
-      DEBUG_LOG(LOGF_Refclock, "refclock pulse ignored no ref sample");
+    if (!SPF_GetLastSample(lock_refclock->filter, &ref_sample)) {
+      DEBUG_LOG("refclock pulse ignored no ref sample");
      return 0;
    }

-    ref_dispersion += filter_get_avg_sample_dispersion(&lock_refclock->filter);
+    ref_sample.root_dispersion += SPF_GetAvgSampleDispersion(lock_refclock->filter);

-    UTI_DiffTimevalsToDouble(&sample_diff, &cooked_time, &ref_sample_time);
-    if (fabs(sample_diff) >= 2.0 / rate) {
-      DEBUG_LOG(LOGF_Refclock, "refclock pulse ignored samplediff=%.9f",
+    sample_diff = UTI_DiffTimespecsToDouble(cooked_time, &ref_sample.time);
+    if (fabs(sample_diff) >= (double)instance->max_lock_age / rate) {
+      DEBUG_LOG("refclock pulse ignored samplediff=%.9f",
          sample_diff);
      return 0;
    }

    /* Align the offset to the reference sample */
-    if ((ref_offset - offset) >= 0.0)
-      shift = (long)((ref_offset - offset) * rate + 0.5) / (double)rate;
+    if ((ref_sample.offset - offset) >= 0.0)
+      shift = (long)((ref_sample.offset - offset) * rate + 0.5) / (double)rate;
    else
-      shift = (long)((ref_offset - offset) * rate - 0.5) / (double)rate;
+      shift = (long)((ref_sample.offset - offset) * rate - 0.5) / (double)rate;

    offset += shift;

-    if (fabs(ref_offset - offset) + ref_dispersion + dispersion >= 0.2 / rate) {
-      DEBUG_LOG(LOGF_Refclock, "refclock pulse ignored offdiff=%.9f refdisp=%.9f disp=%.9f",
-          ref_offset - offset, ref_dispersion, dispersion);
+    if (fabs(ref_sample.offset - offset) +
+        ref_sample.root_dispersion + dispersion >= 0.2 / rate) {
+      DEBUG_LOG("refclock pulse ignored offdiff=%.9f refdisp=%.9f disp=%.9f",
+                ref_sample.offset - offset, ref_sample.root_dispersion, dispersion);
      return 0;
    }

+    if (!check_pulse_edge(instance, ref_sample.offset - offset, 0.0))
+      return 0;
+
    leap = lock_refclock->leap_status;

-    DEBUG_LOG(LOGF_Refclock, "refclock pulse second=%.9f offset=%.9f offdiff=%.9f samplediff=%.9f",
-        second, offset, ref_offset - offset, sample_diff);
+    DEBUG_LOG("refclock pulse offset=%.9f offdiff=%.9f samplediff=%.9f",
+              offset, ref_sample.offset - offset, sample_diff);
  } else {
-    struct timeval ref_time;
+    struct timespec ref_time;
    int is_synchronised, stratum;
    double root_delay, root_dispersion, distance;
    uint32_t ref_id;
@@ -477,24 +588,30 @@ RCL_AddPulse(RCL_Instance instance, struct timeval *pulse_time, double second)
    /* Ignore the pulse if we are not well synchronized and the local
       reference is not active */

-    REF_GetReferenceParams(&cooked_time, &is_synchronised, &leap, &stratum,
+    REF_GetReferenceParams(cooked_time, &is_synchronised, &leap, &stratum,
        &ref_id, &ref_time, &root_delay, &root_dispersion);
    distance = fabs(root_delay) / 2 + root_dispersion;

    if (leap == LEAP_Unsynchronised || distance >= 0.5 / rate) {
-      DEBUG_LOG(LOGF_Refclock, "refclock pulse ignored second=%.9f sync=%d dist=%.9f",
-          second, leap != LEAP_Unsynchronised, distance);
+      DEBUG_LOG("refclock pulse ignored offset=%.9f sync=%d dist=%.9f",
+                offset, leap != LEAP_Unsynchronised, distance);
      /* Drop also all stored samples */
-      filter_reset(&instance->filter);
+      SPF_DropSamples(instance->filter);
      return 0;
    }
+
+    if (!check_pulse_edge(instance, offset, distance))
+      return 0;
  }

-  filter_add_sample(&instance->filter, &cooked_time, offset, dispersion);
+  if (!accumulate_sample(instance, cooked_time, offset, dispersion))
+    return 0;
+
  instance->leap_status = leap;
  instance->pps_active = 1;

-  log_sample(instance, &cooked_time, 0, 1, offset + correction - instance->offset, offset, dispersion);
+  log_sample(instance, cooked_time, 0, 1, offset + raw_correction - instance->offset,
+             offset, dispersion);

  /* for logging purposes */
  if (!instance->driver->poll)
@@ -503,23 +620,31 @@ RCL_AddPulse(RCL_Instance instance, struct timeval *pulse_time, double second)
  return 1;
 }

-static int
-valid_sample_time(RCL_Instance instance, struct timeval *raw, struct timeval *cooked)
+double
+RCL_GetPrecision(RCL_Instance instance)
 {
-  struct timeval raw_time, last_sample_time;
-  double diff, last_offset, last_dispersion;
+  return instance->precision;
+}

-  LCL_ReadRawTime(&raw_time);
-  UTI_DiffTimevalsToDouble(&diff, &raw_time, raw);
+int
+RCL_GetDriverPoll(RCL_Instance instance)
+{
+  return instance->driver_poll;
+}

-  if (diff < 0.0 || diff > UTI_Log2ToDouble(instance->poll + 1) ||
-      (filter_get_samples(&instance->filter) > 0 &&
-       filter_get_last_sample(&instance->filter, &last_sample_time,
-                              &last_offset, &last_dispersion) &&
-       UTI_CompareTimevals(&last_sample_time, cooked) >= 0)) {
-    DEBUG_LOG(LOGF_Refclock, "%s refclock sample not valid age=%.6f raw=%s cooked=%s",
-              UTI_RefidToString(instance->ref_id), diff,
-              UTI_TimevalToString(raw), UTI_TimevalToString(cooked));
+static int
+valid_sample_time(RCL_Instance instance, struct timespec *sample_time)
+{
+  struct timespec now;
+  double diff;
+
+  LCL_ReadCookedTime(&now, NULL);
+  diff = UTI_DiffTimespecsToDouble(&now, sample_time);
+
+  if (diff < 0.0 || diff > UTI_Log2ToDouble(instance->poll + 1)) {
+    DEBUG_LOG("%s refclock sample time %s not valid age=%.6f",
+              UTI_RefidToString(instance->ref_id),
+              UTI_TimespecToString(sample_time), diff);
    return 0;
  }

@@ -527,9 +652,9 @@ valid_sample_time(RCL_Instance instance, struct timeval *raw, struct timeval *co
 }

 static int
-pps_stratum(RCL_Instance instance, struct timeval *tv)
+pps_stratum(RCL_Instance instance, struct timespec *ts)
 {
-  struct timeval ref_time;
+  struct timespec ref_time;
  int is_synchronised, stratum;
  unsigned int i;
  double root_delay, root_dispersion;
@@ -537,7 +662,7 @@ pps_stratum(RCL_Instance instance, struct timeval *tv)
  uint32_t ref_id;
  RCL_Instance refclock;

-  REF_GetReferenceParams(tv, &is_synchronised, &leap, &stratum,
+  REF_GetReferenceParams(ts, &is_synchronised, &leap, &stratum,
      &ref_id, &ref_time, &root_delay, &root_dispersion);

  /* Don't change our stratum if the local reference is active
@@ -560,6 +685,7 @@ pps_stratum(RCL_Instance instance, struct timeval *tv)
 static void
 poll_timeout(void *arg)
 {
+  NTP_Sample sample;
  int poll;

  RCL_Instance inst = (RCL_Instance)arg;
@@ -573,26 +699,15 @@ poll_timeout(void *arg)
  }
  
  if (!(inst->driver->poll && inst->driver_polled < (1 << (inst->poll - inst->driver_poll)))) {
-    double offset, dispersion;
-    struct timeval sample_time;
-    int sample_ok, stratum;
-
-    sample_ok = filter_get_sample(&inst->filter, &sample_time, &offset, &dispersion);
    inst->driver_polled = 0;

-    if (sample_ok) {
-      if (inst->pps_active && inst->lock_ref == -1)
-        /* Handle special case when PPS is used with local stratum */
-        stratum = pps_stratum(inst, &sample_time);
-      else
-        stratum = 0;
-
+    if (SPF_GetFilteredSample(inst->filter, &sample)) {
      SRC_UpdateReachability(inst->source, 1);
-      SRC_AccumulateSample(inst->source, &sample_time, offset,
-          inst->delay, dispersion, inst->delay, dispersion, stratum, inst->leap_status);
+      SRC_SetLeapStatus(inst->source, inst->leap_status);
+      SRC_AccumulateSample(inst->source, &sample);
      SRC_SelectSource(inst->source);

-      log_sample(inst, &sample_time, 1, 0, 0.0, offset, dispersion);
+      log_sample(inst, &sample.time, 1, 0, 0.0, sample.offset, sample.peer_dispersion);
    } else {
      SRC_UpdateReachability(inst->source, 0);
    }
@@ -602,16 +717,16 @@ poll_timeout(void *arg)
 }

 static void
-slew_samples(struct timeval *raw, struct timeval *cooked, double dfreq,
+slew_samples(struct timespec *raw, struct timespec *cooked, double dfreq,
             double doffset, LCL_ChangeType change_type, void *anything)
 {
  unsigned int i;

  for (i = 0; i < ARR_GetSize(refclocks); i++) {
    if (change_type == LCL_ChangeUnknownStep)
-      filter_reset(&get_refclock(i)->filter);
+      SPF_DropSamples(get_refclock(i)->filter);
    else
-      filter_slew_samples(&get_refclock(i)->filter, cooked, dfreq, doffset);
+      SPF_SlewSamples(get_refclock(i)->filter, cooked, dfreq, doffset);
  }
 }

@@ -621,11 +736,11 @@ add_dispersion(double dispersion, void *anything)
  unsigned int i;

  for (i = 0; i < ARR_GetSize(refclocks); i++)
-    filter_add_dispersion(&get_refclock(i)->filter, dispersion);
+    SPF_AddDispersion(get_refclock(i)->filter, dispersion);
 }

 static void
-log_sample(RCL_Instance instance, struct timeval *sample_time, int filtered, int pulse, double raw_offset, double cooked_offset, double dispersion)
+log_sample(RCL_Instance instance, struct timespec *sample_time, int filtered, int pulse, double raw_offset, double cooked_offset, double dispersion)
 {
  char sync_stats[4] = {'N', '+', '-', '?'};

@@ -635,7 +750,7 @@ log_sample(RCL_Instance instance, struct timeval *sample_time, int filtered, int
  if (!filtered) {
    LOG_FileWrite(logfileid, "%s.%06d %-5s %3d %1c %1d %13.6e %13.6e %10.3e",
      UTI_TimeToLogForm(sample_time->tv_sec),
-      (int)sample_time->tv_usec,
+      (int)sample_time->tv_nsec / 1000,
      UTI_RefidToString(instance->ref_id),
      instance->driver_polled,
      sync_stats[instance->leap_status],
@@ -646,316 +761,10 @@ log_sample(RCL_Instance instance, struct timeval *sample_time, int filtered, int
  } else {
    LOG_FileWrite(logfileid, "%s.%06d %-5s   - %1c -       -       %13.6e %10.3e",
      UTI_TimeToLogForm(sample_time->tv_sec),
-      (int)sample_time->tv_usec,
+      (int)sample_time->tv_nsec / 1000,
      UTI_RefidToString(instance->ref_id),
      sync_stats[instance->leap_status],
      cooked_offset,
      dispersion);
  }
 }
-
-static void
-filter_init(struct MedianFilter *filter, int length, double max_dispersion)
-{
-  if (length < 1)
-    length = 1;
-
-  filter->length = length;
-  filter->index = -1;
-  filter->used = 0;
-  filter->last = -1;
-  /* set first estimate to system precision */
-  filter->avg_var_n = 0;
-  filter->avg_var = LCL_GetSysPrecisionAsQuantum() * LCL_GetSysPrecisionAsQuantum();
-  filter->max_var = max_dispersion * max_dispersion;
-  filter->samples = MallocArray(struct FilterSample, filter->length);
-  filter->selected = MallocArray(int, filter->length);
-  filter->x_data = MallocArray(double, filter->length);
-  filter->y_data = MallocArray(double, filter->length);
-  filter->w_data = MallocArray(double, filter->length);
-}
-
-static void
-filter_fini(struct MedianFilter *filter)
-{
-  Free(filter->samples);
-  Free(filter->selected);
-  Free(filter->x_data);
-  Free(filter->y_data);
-  Free(filter->w_data);
-}
-
-static void
-filter_reset(struct MedianFilter *filter)
-{
-  filter->index = -1;
-  filter->used = 0;
-}
-
-static double
-filter_get_avg_sample_dispersion(struct MedianFilter *filter)
-{
-  return sqrt(filter->avg_var);
-}
-
-static void
-filter_add_sample(struct MedianFilter *filter, struct timeval *sample_time, double offset, double dispersion)
-{
-  filter->index++;
-  filter->index %= filter->length;
-  filter->last = filter->index;
-  if (filter->used < filter->length)
-    filter->used++;
-
-  filter->samples[filter->index].sample_time = *sample_time;
-  filter->samples[filter->index].offset = offset;
-  filter->samples[filter->index].dispersion = dispersion;
-
-  DEBUG_LOG(LOGF_Refclock, "filter sample %d t=%s offset=%.9f dispersion=%.9f",
-      filter->index, UTI_TimevalToString(sample_time), offset, dispersion);
-}
-
-static int
-filter_get_last_sample(struct MedianFilter *filter, struct timeval *sample_time, double *offset, double *dispersion)
-{
-  if (filter->last < 0)
-    return 0;
-
-  *sample_time = filter->samples[filter->last].sample_time;
-  *offset = filter->samples[filter->last].offset;
-  *dispersion = filter->samples[filter->last].dispersion;
-  return 1;
-}
-
-static int
-filter_get_samples(struct MedianFilter *filter)
-{
-  return filter->used;
-}
-
-static const struct FilterSample *tmp_sorted_array;
-
-static int
-sample_compare(const void *a, const void *b)
-{
-  const struct FilterSample *s1, *s2;
-
-  s1 = &tmp_sorted_array[*(int *)a];
-  s2 = &tmp_sorted_array[*(int *)b];
-
-  if (s1->offset < s2->offset)
-    return -1;
-  else if (s1->offset > s2->offset)
-    return 1;
-  return 0;
-}
-
-int
-filter_select_samples(struct MedianFilter *filter)
-{
-  int i, j, k, o, from, to, *selected;
-  double min_dispersion;
-
-  if (filter->used < 1)
-    return 0;
-
-  /* for lengths below 4 require full filter,
-     for 4 and above require at least 4 samples */
-  if ((filter->length < 4 && filter->used != filter->length) ||
-      (filter->length >= 4 && filter->used < 4))
-    return 0;
-
-  selected = filter->selected;
-
-  if (filter->used > 4) {
-    /* select samples with dispersion better than 1.5 * minimum */
-
-    for (i = 1, min_dispersion = filter->samples[0].dispersion; i < filter->used; i++) {
-      if (min_dispersion > filter->samples[i].dispersion)
-        min_dispersion = filter->samples[i].dispersion;
-    }
-
-    for (i = j = 0; i < filter->used; i++) {
-      if (filter->samples[i].dispersion <= 1.5 * min_dispersion)
-        selected[j++] = i;
-    }
-  } else {
-    j = 0;
-  }
-
-  if (j < 4) {
-    /* select all samples */
-
-    for (j = 0; j < filter->used; j++)
-      selected[j] = j;
-  }
-
-  /* and sort their indices by offset */
-  tmp_sorted_array = filter->samples;
-  qsort(selected, j, sizeof (int), sample_compare);
-
-  /* select 60 percent of the samples closest to the median */ 
-  if (j > 2) {
-    from = j / 5;
-    if (from < 1)
-      from = 1;
-    to = j - from;
-  } else {
-    from = 0;
-    to = j;
-  }
-
-  /* mark unused samples and sort the rest from oldest to newest */
-
-  o = filter->used - filter->index - 1;
-
-  for (i = 0; i < from; i++)
-    selected[i] = -1;
-  for (; i < to; i++)
-    selected[i] = (selected[i] + o) % filter->used;
-  for (; i < filter->used; i++)
-    selected[i] = -1;
-
-  for (i = from; i < to; i++) {
-    j = selected[i];
-    selected[i] = -1;
-    while (j != -1 && selected[j] != j) {
-      k = selected[j];
-      selected[j] = j;
-      j = k;
-    }
-  }
-
-  for (i = j = 0, k = -1; i < filter->used; i++) {
-    if (selected[i] != -1)
-      selected[j++] = (selected[i] + filter->used - o) % filter->used;
-  }
-
-  return j;
-}
-
-static int
-filter_get_sample(struct MedianFilter *filter, struct timeval *sample_time, double *offset, double *dispersion)
-{
-  struct FilterSample *s, *ls;
-  int i, n, dof;
-  double x, y, d, e, var, prev_avg_var;
-
-  n = filter_select_samples(filter);
-
-  if (n < 1)
-    return 0;
-
-  ls = &filter->samples[filter->selected[n - 1]];
-
-  /* prepare data */
-  for (i = 0; i < n; i++) {
-    s = &filter->samples[filter->selected[i]];
-
-    UTI_DiffTimevalsToDouble(&filter->x_data[i], &s->sample_time, &ls->sample_time);
-    filter->y_data[i] = s->offset;
-    filter->w_data[i] = s->dispersion;
-  }
-
-  /* mean offset, sample time and sample dispersion */ 
-  for (i = 0, x = y = e = 0.0; i < n; i++) {
-    x += filter->x_data[i];
-    y += filter->y_data[i];
-    e += filter->w_data[i];
-  }
-  x /= n;
-  y /= n;
-  e /= n;
-
-  if (n >= 4) {
-    double b0, b1, s2, sb0, sb1;
-
-    /* set y axis to the mean sample time */
-    for (i = 0; i < n; i++)
-      filter->x_data[i] -= x;
-
-    /* make a linear fit and use the estimated standard deviation of intercept
-       as dispersion */
-    RGR_WeightedRegression(filter->x_data, filter->y_data, filter->w_data, n,
-        &b0, &b1, &s2, &sb0, &sb1);
-    var = s2;
-    d = sb0;
-    dof = n - 2;
-  } else if (n >= 2) {
-    for (i = 0, d = 0.0; i < n; i++)
-      d += (filter->y_data[i] - y) * (filter->y_data[i] - y);
-    var = d / (n - 1);
-    d = sqrt(var);
-    dof = n - 1;
-  } else {
-    var = filter->avg_var;
-    d = sqrt(var);
-    dof = 1;
-  }
-
-  /* avoid having zero dispersion */
-  if (var < 1e-20) {
-    var = 1e-20;
-    d = sqrt(var);
-  }
-
-  /* drop the sample if variance is larger than allowed maximum */
-  if (filter->max_var > 0.0 && var > filter->max_var) {
-    DEBUG_LOG(LOGF_Refclock, "filter dispersion too large disp=%.9f max=%.9f",
-        sqrt(var), sqrt(filter->max_var));
-    return 0;
-  }
-
-  prev_avg_var = filter->avg_var;
-
-  /* update exponential moving average of the variance */
-  if (filter->avg_var_n > 50) {
-    filter->avg_var += dof / (dof + 50.0) * (var - filter->avg_var);
-  } else {
-    filter->avg_var = (filter->avg_var * filter->avg_var_n + var * dof) /
-      (dof + filter->avg_var_n);
-    if (filter->avg_var_n == 0)
-      prev_avg_var = filter->avg_var;
-    filter->avg_var_n += dof;
-  }
-
-  /* reduce noise in sourcestats weights by using the long-term average
-     instead of the estimated variance if it's not significantly lower */
-  if (var * dof / RGR_GetChi2Coef(dof) < prev_avg_var)
-    d = sqrt(filter->avg_var) * d / sqrt(var);
-
-  if (d < e)
-    d = e;
-
-  UTI_AddDoubleToTimeval(&ls->sample_time, x, sample_time);
-  *offset = y;
-  *dispersion = d;
-
-  filter_reset(filter);
-
-  return 1;
-}
-
-static void
-filter_slew_samples(struct MedianFilter *filter, struct timeval *when, double dfreq, double doffset)
-{
-  int i;
-  double delta_time;
-  struct timeval *sample;
-
-  for (i = 0; i < filter->used; i++) {
-    sample = &filter->samples[i].sample_time;
-    UTI_AdjustTimeval(sample, when, sample, &delta_time, dfreq, doffset);
-    filter->samples[i].offset -= delta_time;
-  }
-}
-
-static void
-filter_add_dispersion(struct MedianFilter *filter, double dispersion)
-{
-  int i;
-
-  for (i = 0; i < filter->used; i++) {
-    filter->samples[i].dispersion += dispersion;
-  }
-}
--- a/refclock.h
+++ b/refclock.h
@@ -37,16 +37,21 @@ typedef struct {
  int driver_poll;
  int poll;
  int filter_length;
+  int pps_forced;
  int pps_rate;
  int min_samples;
  int max_samples;
  int sel_options;
+  int max_lock_age;
+  int stratum;
+  int tai;
  uint32_t ref_id;
  uint32_t lock_ref_id;
  double offset;
  double delay;
  double precision;
  double max_dispersion;
+  double pulse_width;
 } RefclockParameters;

 typedef struct RCL_Instance_Record *RCL_Instance;
@@ -61,14 +66,19 @@ extern void RCL_Initialise(void);
 extern void RCL_Finalise(void);
 extern int RCL_AddRefclock(RefclockParameters *params);
 extern void RCL_StartRefclocks(void);
-extern void RCL_ReportSource(RPT_SourceReport *report, struct timeval *now);
+extern void RCL_ReportSource(RPT_SourceReport *report, struct timespec *now);

 /* functions used by drivers */
 extern void RCL_SetDriverData(RCL_Instance instance, void *data);
 extern void *RCL_GetDriverData(RCL_Instance instance);
 extern char *RCL_GetDriverParameter(RCL_Instance instance);
+extern void RCL_CheckDriverOptions(RCL_Instance instance, const char **options);
 extern char *RCL_GetDriverOption(RCL_Instance instance, char *name);
-extern int RCL_AddSample(RCL_Instance instance, struct timeval *sample_time, double offset, int leap);
-extern int RCL_AddPulse(RCL_Instance instance, struct timeval *pulse_time, double second);
+extern int RCL_AddSample(RCL_Instance instance, struct timespec *sample_time, double offset, int leap);
+extern int RCL_AddPulse(RCL_Instance instance, struct timespec *pulse_time, double second);
+extern int RCL_AddCookedPulse(RCL_Instance instance, struct timespec *cooked_time,
+                              double second, double dispersion, double raw_correction);
+extern double RCL_GetPrecision(RCL_Instance instance);
+extern int RCL_GetDriverPoll(RCL_Instance instance);

 #endif
--- a/refclock_phc.c
+++ b/refclock_phc.c
@@ -2,7 +2,7 @@
  chronyd/chronyc - Programs for keeping computer clocks accurate.

 **********************************************************************
- * Copyright (C) Miroslav Lichvar  2013
+ * Copyright (C) Miroslav Lichvar  2013, 2017
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
@@ -33,151 +33,137 @@

 #include "sysincl.h"

-#include <linux/ptp_clock.h>
-
 #include "refclock.h"
+#include "hwclock.h"
+#include "local.h"
 #include "logging.h"
+#include "memory.h"
 #include "util.h"
+#include "sched.h"
+#include "sys_linux.h"

-/* From linux/include/linux/posix-timers.h */
-#define CPUCLOCK_MAX            3
-#define CLOCKFD                 CPUCLOCK_MAX
-#define CLOCKFD_MASK            (CPUCLOCK_PERTHREAD_MASK|CPUCLOCK_CLOCK_MASK)
-
-#define FD_TO_CLOCKID(fd)       ((~(clockid_t) (fd) << 3) | CLOCKFD)
-
-#define NUM_READINGS 10
-
-static int no_sys_offset_ioctl = 0;
-
-struct phc_reading {
-  struct timespec sys_ts1;
-  struct timespec phc_ts;;
-  struct timespec sys_ts2;
+struct phc_instance {
+  int fd;
+  int mode;
+  int nocrossts;
+  int extpps;
+  int pin;
+  int channel;
+  HCL_Instance clock;
 };

-static double diff_ts(struct timespec *ts1, struct timespec *ts2)
-{
-  return (ts1->tv_sec - ts2->tv_sec) + (ts1->tv_nsec - ts2->tv_nsec) / 1e9;
-}
-
-static int read_phc_ioctl(struct phc_reading *readings, int phc_fd, int n)
-{
-#if defined(PTP_SYS_OFFSET) && NUM_READINGS <= PTP_MAX_SAMPLES
-  struct ptp_sys_offset sys_off;
-  int i;
-
-  /* Silence valgrind */
-  memset(&sys_off, 0, sizeof (sys_off));
-
-  sys_off.n_samples = n;
-  if (ioctl(phc_fd, PTP_SYS_OFFSET, &sys_off)) {
-    LOG(LOGS_ERR, LOGF_Refclock, "ioctl(PTP_SYS_OFFSET) failed : %s", strerror(errno));
-    return 0;
-  }
-
-  for (i = 0; i < n; i++) {
-    readings[i].sys_ts1.tv_sec = sys_off.ts[i * 2].sec;
-    readings[i].sys_ts1.tv_nsec = sys_off.ts[i * 2].nsec;
-    readings[i].phc_ts.tv_sec = sys_off.ts[i * 2 + 1].sec;
-    readings[i].phc_ts.tv_nsec = sys_off.ts[i * 2 + 1].nsec;
-    readings[i].sys_ts2.tv_sec = sys_off.ts[i * 2 + 2].sec;
-    readings[i].sys_ts2.tv_nsec = sys_off.ts[i * 2 + 2].nsec;
-  }
-
-  return 1;
-#else
-  /* Not available */
-  return 0;
-#endif
-}
-
-static int read_phc_user(struct phc_reading *readings, int phc_fd, int n)
-{
-  clockid_t phc_id;
-  int i;
-
-  phc_id = FD_TO_CLOCKID(phc_fd);
-
-  for (i = 0; i < n; i++) {
-    if (clock_gettime(CLOCK_REALTIME, &readings[i].sys_ts1) ||
-        clock_gettime(phc_id, &readings[i].phc_ts) ||
-        clock_gettime(CLOCK_REALTIME, &readings[i].sys_ts2)) {
-      LOG(LOGS_ERR, LOGF_Refclock, "clock_gettime() failed : %s", strerror(errno));
-      return 0;
-    }
-  }
-
-  return 1;
-}
+static void read_ext_pulse(int sockfd, int event, void *anything);

 static int phc_initialise(RCL_Instance instance)
 {
-  struct ptp_clock_caps caps;
-  int phc_fd;
-  char *path;
+  const char *options[] = {"nocrossts", "extpps", "pin", "channel", "clear", NULL};
+  struct phc_instance *phc;
+  int phc_fd, rising_edge;
+  char *path, *s;
+
+  RCL_CheckDriverOptions(instance, options);

  path = RCL_GetDriverParameter(instance);
 
-  phc_fd = open(path, O_RDONLY);
+  phc_fd = SYS_Linux_OpenPHC(path, 0);
  if (phc_fd < 0) {
-    LOG_FATAL(LOGF_Refclock, "open() failed on %s", path);
+    LOG_FATAL("Could not open PHC");
    return 0;
  }

-  /* Make sure it is a PHC */
-  if (ioctl(phc_fd, PTP_CLOCK_GETCAPS, &caps)) {
-    LOG_FATAL(LOGF_Refclock, "ioctl(PTP_CLOCK_GETCAPS) failed : %s", strerror(errno));
-    return 0;
+  phc = MallocNew(struct phc_instance);
+  phc->fd = phc_fd;
+  phc->mode = 0;
+  phc->nocrossts = RCL_GetDriverOption(instance, "nocrossts") ? 1 : 0;
+  phc->extpps = RCL_GetDriverOption(instance, "extpps") ? 1 : 0;
+
+  if (phc->extpps) {
+    s = RCL_GetDriverOption(instance, "pin");
+    phc->pin = s ? atoi(s) : 0;
+    s = RCL_GetDriverOption(instance, "channel");
+    phc->channel = s ? atoi(s) : 0;
+    rising_edge = RCL_GetDriverOption(instance, "clear") ? 0 : 1;
+    phc->clock = HCL_CreateInstance(0, 16, UTI_Log2ToDouble(RCL_GetDriverPoll(instance)));
+
+    if (!SYS_Linux_SetPHCExtTimestamping(phc->fd, phc->pin, phc->channel,
+                                         rising_edge, !rising_edge, 1))
+      LOG_FATAL("Could not enable external PHC timestamping");
+
+    SCH_AddFileHandler(phc->fd, SCH_FILE_INPUT, read_ext_pulse, instance);
+  } else {
+    phc->pin = phc->channel = 0;
+    phc->clock = NULL;
  }

-  UTI_FdSetCloexec(phc_fd);
-
-  RCL_SetDriverData(instance, (void *)(long)phc_fd);
+  RCL_SetDriverData(instance, phc);
  return 1;
 }

 static void phc_finalise(RCL_Instance instance)
 {
-  close((long)RCL_GetDriverData(instance));
+  struct phc_instance *phc;
+
+  phc = (struct phc_instance *)RCL_GetDriverData(instance);
+
+  if (phc->extpps) {
+    SCH_RemoveFileHandler(phc->fd);
+    SYS_Linux_SetPHCExtTimestamping(phc->fd, phc->pin, phc->channel, 0, 0, 0);
+    HCL_DestroyInstance(phc->clock);
+  }
+
+  close(phc->fd);
+  Free(phc);
+}
+
+static void read_ext_pulse(int fd, int event, void *anything)
+{
+  RCL_Instance instance;
+  struct phc_instance *phc;
+  struct timespec phc_ts, local_ts;
+  double local_err;
+  int channel;
+
+  instance = anything;
+  phc = RCL_GetDriverData(instance);
+
+  if (!SYS_Linux_ReadPHCExtTimestamp(phc->fd, &phc_ts, &channel))
+    return;
+
+  if (channel != phc->channel) {
+    DEBUG_LOG("Unexpected extts channel %d\n", channel);
+    return;
+  }
+
+  if (!HCL_CookTime(phc->clock, &phc_ts, &local_ts, &local_err))
+    return;
+
+  RCL_AddCookedPulse(instance, &local_ts, 1.0e-9 * local_ts.tv_nsec, local_err,
+                     UTI_DiffTimespecsToDouble(&phc_ts, &local_ts));
 }

 static int phc_poll(RCL_Instance instance)
 {
-  struct phc_reading readings[NUM_READINGS];
-  struct timeval tv;
-  double offset = 0.0, delay, best_delay = 0.0;
-  int i, phc_fd, best;
- 
-  phc_fd = (long)RCL_GetDriverData(instance);
+  struct phc_instance *phc;
+  struct timespec phc_ts, sys_ts, local_ts;
+  double offset, phc_err, local_err;

-  if (!no_sys_offset_ioctl) {
-    if (!read_phc_ioctl(readings, phc_fd, NUM_READINGS)) {
-      no_sys_offset_ioctl = 1;
-      return 0;
-    }
-  } else {
-    if (!read_phc_user(readings, phc_fd, NUM_READINGS))
-      return 0;
+  phc = (struct phc_instance *)RCL_GetDriverData(instance);
+
+  if (!SYS_Linux_GetPHCSample(phc->fd, phc->nocrossts, RCL_GetPrecision(instance),
+                              &phc->mode, &phc_ts, &sys_ts, &phc_err))
+    return 0;
+
+  if (phc->extpps) {
+    LCL_CookTime(&sys_ts, &local_ts, &local_err);
+    HCL_AccumulateSample(phc->clock, &phc_ts, &local_ts, phc_err + local_err);
+    return 0;
  }

-  /* Find the fastest reading */
-  for (i = 0; i < NUM_READINGS; i++) {
-    delay = diff_ts(&readings[i].sys_ts2, &readings[i].sys_ts1);
+  offset = UTI_DiffTimespecsToDouble(&phc_ts, &sys_ts);

-    if (!i || best_delay > delay) {
-      best = i;
-      best_delay = delay;
-    }
-  }
+  DEBUG_LOG("PHC offset: %+.9f err: %.9f", offset, phc_err);

-  offset = diff_ts(&readings[best].phc_ts, &readings[best].sys_ts2) + best_delay / 2.0;
-  tv.tv_sec = readings[best].sys_ts2.tv_sec;
-  tv.tv_usec = readings[best].sys_ts2.tv_nsec / 1000;
-
-  DEBUG_LOG(LOGF_Refclock, "PHC offset: %+.9f delay: %.9f", offset, best_delay);
-
-  return RCL_AddSample(instance, &tv, offset, LEAP_Normal);
+  return RCL_AddSample(instance, &sys_ts, offset, LEAP_Normal);
 }

 RefclockDriver RCL_PHC_driver = {
--- a/refclock_pps.c
+++ b/refclock_pps.c
@@ -48,48 +48,51 @@ struct pps_instance {
 };

 static int pps_initialise(RCL_Instance instance) {
+  const char *options[] = {"clear", NULL};
  pps_handle_t handle;
  pps_params_t params;
  struct pps_instance *pps;
  int fd, edge_clear, mode;
  char *path;

+  RCL_CheckDriverOptions(instance, options);
+
  path = RCL_GetDriverParameter(instance);
  edge_clear = RCL_GetDriverOption(instance, "clear") ? 1 : 0;

  fd = open(path, O_RDWR);
  if (fd < 0) {
-    LOG_FATAL(LOGF_Refclock, "open() failed on %s", path);
+    LOG_FATAL("Could not open %s : %s", path, strerror(errno));
    return 0;
  }

  UTI_FdSetCloexec(fd);

  if (time_pps_create(fd, &handle) < 0) {
-    LOG_FATAL(LOGF_Refclock, "time_pps_create() failed on %s", path);
+    LOG_FATAL("time_pps_create() failed on %s : %s", path, strerror(errno));
    return 0;
  }

  if (time_pps_getcap(handle, &mode) < 0) {
-    LOG_FATAL(LOGF_Refclock, "time_pps_getcap() failed on %s", path);
+    LOG_FATAL("time_pps_getcap() failed on %s : %s", path, strerror(errno));
    return 0;
  }

  if (time_pps_getparams(handle, &params) < 0) {
-    LOG_FATAL(LOGF_Refclock, "time_pps_getparams() failed on %s", path);
+    LOG_FATAL("time_pps_getparams() failed on %s : %s", path, strerror(errno));
    return 0;
  }

  if (!edge_clear) {
    if (!(mode & PPS_CAPTUREASSERT)) {
-      LOG_FATAL(LOGF_Refclock, "CAPTUREASSERT not supported on %s", path);
+      LOG_FATAL("CAPTUREASSERT not supported on %s", path);
      return 0;
    }
    params.mode |= PPS_CAPTUREASSERT;
    params.mode &= ~PPS_CAPTURECLEAR;
  } else {
    if (!(mode & PPS_CAPTURECLEAR)) {
-      LOG_FATAL(LOGF_Refclock, "CAPTURECLEAR not supported on %s", path);
+      LOG_FATAL("CAPTURECLEAR not supported on %s", path);
      return 0;
    }
    params.mode |= PPS_CAPTURECLEAR;
@@ -97,7 +100,7 @@ static int pps_initialise(RCL_Instance instance) {
  }

  if (time_pps_setparams(handle, &params) < 0) {
-    LOG_FATAL(LOGF_Refclock, "time_pps_setparams() failed on %s", path);
+    LOG_FATAL("time_pps_setparams() failed on %s : %s", path, strerror(errno));
    return 0;
  }

@@ -124,7 +127,6 @@ static int pps_poll(RCL_Instance instance)
 {
  struct pps_instance *pps; 
  struct timespec ts;
-  struct timeval tv;
  pps_info_t pps_info;
  pps_seq_t seq;

@@ -134,7 +136,7 @@ static int pps_poll(RCL_Instance instance)
  ts.tv_nsec = 0;

  if (time_pps_fetch(pps->handle, PPS_TSFMT_TSPEC, &pps_info, &ts) < 0) {
-    LOG(LOGS_ERR, LOGF_Refclock, "time_pps_fetch() failed : %s", strerror(errno));
+    LOG(LOGS_ERR, "time_pps_fetch() failed : %s", strerror(errno));
    return 0;
  }

@@ -146,17 +148,15 @@ static int pps_poll(RCL_Instance instance)
    ts = pps_info.clear_timestamp;
  }

-  if (seq == pps->last_seq || (ts.tv_sec == 0 && ts.tv_nsec == 0)) { 
-    DEBUG_LOG(LOGF_Refclock, "PPS sample ignored seq=%lu ts=%lu.%09lu",
-        seq, ts.tv_sec, ts.tv_nsec);
+  if (seq == pps->last_seq || UTI_IsZeroTimespec(&ts)) {
+    DEBUG_LOG("PPS sample ignored seq=%lu ts=%s",
+              (unsigned long)seq, UTI_TimespecToString(&ts));
    return 0;
  }

  pps->last_seq = seq;
-  tv.tv_sec = ts.tv_sec;
-  tv.tv_usec = ts.tv_nsec / 1000;

-  return RCL_AddPulse(instance, &tv, ts.tv_nsec / 1e9);
+  return RCL_AddPulse(instance, &ts, 1.0e-9 * ts.tv_nsec);
 }

 RefclockDriver RCL_PPS_driver = {
--- a/refclock_shm.c
+++ b/refclock_shm.c
@@ -59,23 +59,26 @@ struct shmTime {
 };

 static int shm_initialise(RCL_Instance instance) {
+  const char *options[] = {"perm", NULL};
  int id, param, perm;
  char *s;
  struct shmTime *shm;

+  RCL_CheckDriverOptions(instance, options);
+
  param = atoi(RCL_GetDriverParameter(instance));
  s = RCL_GetDriverOption(instance, "perm");
  perm = s ? strtol(s, NULL, 8) & 0777 : 0600;

  id = shmget(SHMKEY + param, sizeof (struct shmTime), IPC_CREAT | perm);
  if (id == -1) {
-    LOG_FATAL(LOGF_Refclock, "shmget() failed");
+    LOG_FATAL("shmget() failed : %s", strerror(errno));
    return 0;
  }
   
  shm = (struct shmTime *)shmat(id, 0, 0);
  if ((long)shm == -1) {
-    LOG_FATAL(LOGF_Refclock, "shmat() failed");
+    LOG_FATAL("shmat() failed : %s", strerror(errno));
    return 0;
  }

@@ -90,7 +93,7 @@ static void shm_finalise(RCL_Instance instance)

 static int shm_poll(RCL_Instance instance)
 {
-  struct timeval tv;
+  struct timespec receive_ts, clock_ts;
  struct shmTime t, *shm;
  double offset;

@@ -100,24 +103,30 @@ static int shm_poll(RCL_Instance instance)
  
  if ((t.mode == 1 && t.count != shm->count) ||
    !(t.mode == 0 || t.mode == 1) || !t.valid) {
-    DEBUG_LOG(LOGF_Refclock, "SHM sample ignored mode=%d count=%d valid=%d",
+    DEBUG_LOG("SHM sample ignored mode=%d count=%d valid=%d",
        t.mode, t.count, t.valid);
    return 0;
  }

  shm->valid = 0;

-  tv.tv_sec = t.receiveTimeStampSec;
-  tv.tv_usec = t.receiveTimeStampUSec;
+  receive_ts.tv_sec = t.receiveTimeStampSec;
+  clock_ts.tv_sec = t.clockTimeStampSec;

-  offset = t.clockTimeStampSec - t.receiveTimeStampSec;
  if (t.clockTimeStampNSec / 1000 == t.clockTimeStampUSec &&
-      t.receiveTimeStampNSec / 1000 == t.receiveTimeStampUSec)
-    offset += (t.clockTimeStampNSec - t.receiveTimeStampNSec) * 1e-9;
-  else
-    offset += (t.clockTimeStampUSec - t.receiveTimeStampUSec) * 1e-6;
+      t.receiveTimeStampNSec / 1000 == t.receiveTimeStampUSec) {
+    receive_ts.tv_nsec = t.receiveTimeStampNSec;
+    clock_ts.tv_nsec = t.clockTimeStampNSec;
+  } else {
+    receive_ts.tv_nsec = 1000 * t.receiveTimeStampUSec;
+    clock_ts.tv_nsec = 1000 * t.clockTimeStampUSec;
+  }

-  return RCL_AddSample(instance, &tv, offset, t.leap);
+  UTI_NormaliseTimespec(&clock_ts);
+  UTI_NormaliseTimespec(&receive_ts);
+  offset = UTI_DiffTimespecsToDouble(&clock_ts, &receive_ts);
+
+  return RCL_AddSample(instance, &receive_ts, offset, t.leap);
 }

 RefclockDriver RCL_SHM_driver = {
--- a/refclock_sock.c
+++ b/refclock_sock.c
@@ -33,6 +33,7 @@
 #include "logging.h"
 #include "util.h"
 #include "sched.h"
+#include "socket.h"

 #define SOCK_MAGIC 0x534f434b

@@ -57,72 +58,59 @@ struct sock_sample {
  int magic;
 };

-static void read_sample(void *anything)
+static void read_sample(int sockfd, int event, void *anything)
 {
  struct sock_sample sample;
+  struct timespec ts;
  RCL_Instance instance;
-  int sockfd, s;
+  int s;

  instance = (RCL_Instance)anything;
-  sockfd = (long)RCL_GetDriverData(instance);

  s = recv(sockfd, &sample, sizeof (sample), 0);

  if (s < 0) {
-    LOG(LOGS_ERR, LOGF_Refclock, "Could not read SOCK sample : %s",
-        strerror(errno));
+    DEBUG_LOG("Could not read SOCK sample : %s", strerror(errno));
    return;
  }

  if (s != sizeof (sample)) {
-    LOG(LOGS_WARN, LOGF_Refclock, "Unexpected length of SOCK sample : %d != %ld",
-        s, (long)sizeof (sample));
+    DEBUG_LOG("Unexpected length of SOCK sample : %d != %ld",
+              s, (long)sizeof (sample));
    return;
  }

  if (sample.magic != SOCK_MAGIC) {
-    LOG(LOGS_WARN, LOGF_Refclock, "Unexpected magic number in SOCK sample : %x != %x",
-        sample.magic, SOCK_MAGIC);
+    DEBUG_LOG("Unexpected magic number in SOCK sample : %x != %x",
+              (unsigned int)sample.magic, (unsigned int)SOCK_MAGIC);
    return;
  }

+  UTI_TimevalToTimespec(&sample.tv, &ts);
+  UTI_NormaliseTimespec(&ts);
+
  if (sample.pulse) {
-    RCL_AddPulse(instance, &sample.tv, sample.offset);
+    RCL_AddPulse(instance, &ts, sample.offset);
  } else {
-    RCL_AddSample(instance, &sample.tv, sample.offset, sample.leap);
+    RCL_AddSample(instance, &ts, sample.offset, sample.leap);
  }
 }

 static int sock_initialise(RCL_Instance instance)
 {
-  struct sockaddr_un s;
  int sockfd;
  char *path;

+  RCL_CheckDriverOptions(instance, NULL);
+
  path = RCL_GetDriverParameter(instance);
 
-  s.sun_family = AF_UNIX;
-  if (snprintf(s.sun_path, sizeof (s.sun_path), "%s", path) >= sizeof (s.sun_path)) {
-    LOG_FATAL(LOGF_Refclock, "path %s is too long", path);
-    return 0;
-  }
-
-  sockfd = socket(AF_UNIX, SOCK_DGRAM, 0);
-  if (sockfd < 0) {
-    LOG_FATAL(LOGF_Refclock, "socket() failed");
-    return 0;
-  }
-
-  UTI_FdSetCloexec(sockfd);
-
-  unlink(path);
-  if (bind(sockfd, (struct sockaddr *)&s, sizeof (s)) < 0) {
-    LOG_FATAL(LOGF_Refclock, "bind() failed");
-    return 0;
-  }
+  sockfd = SCK_OpenUnixDatagramSocket(NULL, path, 0);
+  if (sockfd < 0)
+    LOG_FATAL("Could not open socket %s", path);

  RCL_SetDriverData(instance, (void *)(long)sockfd);
-  SCH_AddInputFileHandler(sockfd, read_sample, instance);
+  SCH_AddFileHandler(sockfd, SCH_FILE_INPUT, read_sample, instance);
  return 1;
 }

@@ -131,8 +119,9 @@ static void sock_finalise(RCL_Instance instance)
  int sockfd;

  sockfd = (long)RCL_GetDriverData(instance);
-  SCH_RemoveInputFileHandler(sockfd);
-  close(sockfd);
+  SCH_RemoveFileHandler(sockfd);
+  SCK_RemoveSocket(sockfd);
+  SCK_CloseSocket(sockfd);
 }

 RefclockDriver RCL_SOCK_driver = {
--- a/reference.c
+++ b/reference.c
--- a/reference.h
+++ b/reference.h
@@ -99,12 +99,12 @@ extern REF_LeapMode REF_GetLeapMode(void);

 extern void REF_GetReferenceParams
 (
- struct timeval *local_time,
+ struct timespec *local_time,
 int *is_synchronised,
 NTP_Leap *leap,
 int *stratum,
 uint32_t *ref_id,
- struct timeval *ref_time,
+ struct timespec *ref_time,
 double *root_delay,
 double *root_dispersion
 );
@@ -140,10 +140,11 @@ extern void REF_SetReference
 int combined_sources,
 uint32_t ref_id,
 IPAddr *ref_ip,
- struct timeval *ref_time,
+ struct timespec *ref_time,
 double offset,
 double offset_sd,
 double frequency,
+ double frequency_sd,
 double skew,
 double root_delay,
 double root_dispersion
@@ -151,7 +152,7 @@ extern void REF_SetReference

 extern void REF_SetManualReference
 (
- struct timeval *ref_time,
+ struct timespec *ref_time,
 double offset,
 double frequency,
 double skew
@@ -161,6 +162,9 @@ extern void REF_SetManualReference
 extern void
 REF_SetUnsynchronised(void);

+/* Announce a leap second before the full reference update */
+extern void REF_UpdateLeapStatus(NTP_Leap leap);
+
 /* Return the current stratum of this host or 16 if the host is not
   synchronised */
 extern int REF_GetOurStratum(void);
@@ -184,6 +188,9 @@ extern void REF_DisableLocal(void);
   and is better to discard any measurements */
 extern int REF_IsLeapSecondClose(void);

+/* Return TAI-UTC offset corresponding to a time in UTC if available */
+extern int REF_GetTaiOffset(struct timespec *ts);
+
 extern void REF_GetTrackingReport(RPT_TrackingReport *rep);

 #endif /* GOT_REFERENCE_H */
--- a/regress.c
+++ b/regress.c
@@ -3,7 +3,7 @@

 **********************************************************************
 * Copyright (C) Richard P. Curnow  1997-2003
- * Copyright (C) Miroslav Lichvar  2011
+ * Copyright (C) Miroslav Lichvar  2011, 2016-2017
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
@@ -34,7 +34,7 @@
 #include "logging.h"
 #include "util.h"

-#define MAX_POINTS 128
+#define MAX_POINTS 64

 void
 RGR_WeightedRegression
@@ -109,7 +109,7 @@ double
 RGR_GetTCoef(int dof)
 {
  /* Assuming now the 99.95% quantile */
-  static double coefs[] =
+  static const float coefs[] =
  { 636.6, 31.6, 12.92, 8.61, 6.869,
    5.959, 5.408, 5.041, 4.781, 4.587,
    4.437, 4.318, 4.221, 4.140, 4.073,
@@ -132,7 +132,7 @@ RGR_GetTCoef(int dof)
 double
 RGR_GetChi2Coef(int dof)
 {
-  static double coefs[] = {
+  static const float coefs[] = {
    2.706, 4.605, 6.251, 7.779, 9.236, 10.645, 12.017, 13.362,
    14.684, 15.987, 17.275, 18.549, 19.812, 21.064, 22.307, 23.542,
    24.769, 25.989, 27.204, 28.412, 29.615, 30.813, 32.007, 33.196,
@@ -150,20 +150,6 @@ RGR_GetChi2Coef(int dof)
  }
 }

-/* ================================================== */
-/* Structure used for holding results of each regression */
-
-typedef struct {
-  double variance;
-  double slope_sd;
-  double slope;
-  double offset;
-  double offset_sd;
-  double K2; /* Variance / slope_var */
-  int n; /* Number of points */
-  int dof; /* Number of degrees of freedom */
-} RegressionResult;
-
 /* ================================================== */
 /* Critical value for number of runs of residuals with same sign.
   5% critical region for now. */
@@ -299,7 +285,7 @@ RGR_FindBestRegression
        n - start <= min_samples) {
      if (start != resid_start) {
        /* Ignore extra samples in returned nruns */
-        nruns = n_runs_from_residuals(resid - resid_start + start, n - start);
+        nruns = n_runs_from_residuals(resid + (start - resid_start), n - start);
      }
      break;
    } else {
@@ -354,7 +340,7 @@ RGR_FindBestRegression
   0-521-43108-5). */

 static double
-find_ordered_entry_with_flags(double *x, int n, int index, int *flags)
+find_ordered_entry_with_flags(double *x, int n, int index, char *flags)
 {
  int u, v, l, r;
  double temp;
@@ -417,9 +403,9 @@ find_ordered_entry_with_flags(double *x, int n, int index, int *flags)
 static double
 find_ordered_entry(double *x, int n, int index)
 {
-  int flags[MAX_POINTS];
+  char flags[MAX_POINTS];

-  memset(flags, 0, n * sizeof(int));
+  memset(flags, 0, n * sizeof (flags[0]));
  return find_ordered_entry_with_flags(x, n, index, flags);
 }
 #endif
@@ -431,9 +417,9 @@ static double
 find_median(double *x, int n)
 {
  int k;
-  int flags[MAX_POINTS];
+  char flags[MAX_POINTS];

-  memset(flags, 0, n*sizeof(int));
+  memset(flags, 0, n * sizeof (flags[0]));
  k = n>>1;
  if (n&1) {
    return find_ordered_entry_with_flags(x, n, k, flags);
@@ -443,6 +429,19 @@ find_median(double *x, int n)
  }
 }

+/* ================================================== */
+
+double
+RGR_FindMedian(double *x, int n)
+{
+  double tmp[MAX_POINTS];
+
+  assert(n > 0 && n <= MAX_POINTS);
+  memcpy(tmp, x, n * sizeof (tmp[0]));
+
+  return find_median(tmp, n);
+}
+
 /* ================================================== */
 /* This function evaluates the equation

@@ -523,7 +522,7 @@ RGR_FindBestRobustRegression
  double mx, dx, my, dy;
  int nruns = 0;

-  assert(n < MAX_POINTS);
+  assert(n <= MAX_POINTS);

  if (n < 2) {
    return 0;
@@ -580,24 +579,18 @@ RGR_FindBestRobustRegression
       Estimate standard deviation of b and expand range about b based
       on that. */
    sb = sqrt(s2 * W/V);
-    if (sb > tol) {
-      incr = 3.0 * sb;
-    } else {
-      incr = 3.0 * tol;
-    }
+    incr = MAX(sb, tol);
  
-    blo = b;
-    bhi = b;
-
    do {
-      /* Make sure incr is significant to blo and bhi */
-      while (bhi + incr == bhi || blo - incr == blo) {
-        incr *= 2;
-      }
+      incr *= 2.0;
+
+      /* Give up if the interval is too large */
+      if (incr > 100.0)
+        return 0;
+
+      blo = b - incr;
+      bhi = b + incr;

-      blo -= incr;
-      bhi += incr;
-      
      /* We don't want 'a' yet */
      eval_robust_residual(x + start, y + start, n_points, blo, &a, &rlo);
      eval_robust_residual(x + start, y + start, n_points, bhi, &a, &rhi);
@@ -608,6 +601,8 @@ RGR_FindBestRobustRegression
    /* OK, so the root for b lies in (blo, bhi). Start bisecting */
    do {
      bmid = 0.5 * (blo + bhi);
+      if (!(blo < bmid && bmid < bhi))
+        break;
      eval_robust_residual(x + start, y + start, n_points, bmid, &a, &rmid);
      if (rmid == 0.0) {
        break;
@@ -620,7 +615,7 @@ RGR_FindBestRobustRegression
      } else {
        assert(0);
      }
-    } while ((bhi - blo) > tol && (bmid - blo) * (bhi - bmid) > 0.0);
+    } while (bhi - blo > tol);

    *b0 = a;
    *b1 = bmid;
@@ -653,3 +648,57 @@ RGR_FindBestRobustRegression
 }

 /* ================================================== */
+/* This routine performs linear regression with two independent variables.
+   It returns non-zero status if there were enough data points and there
+   was a solution. */
+
+int
+RGR_MultipleRegress
+(double *x1,                    /* first independent variable */
+ double *x2,                    /* second independent variable */
+ double *y,                     /* measured data */
+
+ int n,                         /* number of data points */
+
+ /* The results */
+ double *b2                     /* estimated second slope */
+                                /* other values are not needed yet */
+)
+{
+  double Sx1, Sx2, Sx1x1, Sx1x2, Sx2x2, Sx1y, Sx2y, Sy;
+  double U, V, V1, V2, V3;
+  int i;
+
+  if (n < 4)
+    return 0;
+
+  Sx1 = Sx2 = Sx1x1 = Sx1x2 = Sx2x2 = Sx1y = Sx2y = Sy = 0.0;
+
+  for (i = 0; i < n; i++) {
+    Sx1 += x1[i];
+    Sx2 += x2[i];
+    Sx1x1 += x1[i] * x1[i];
+    Sx1x2 += x1[i] * x2[i];
+    Sx2x2 += x2[i] * x2[i];
+    Sx1y += x1[i] * y[i];
+    Sx2y += x2[i] * y[i];
+    Sy += y[i];
+  }
+
+  U = n * (Sx1x2 * Sx1y - Sx1x1 * Sx2y) +
+      Sx1 * Sx1 * Sx2y - Sx1 * Sx2 * Sx1y +
+      Sy * (Sx2 * Sx1x1 - Sx1 * Sx1x2);
+
+  V1 = n * (Sx1x2 * Sx1x2 - Sx1x1 * Sx2x2);
+  V2 = Sx1 * Sx1 * Sx2x2 + Sx2 * Sx2 * Sx1x1;
+  V3 = -2.0 * Sx1 * Sx2 * Sx1x2;
+  V = V1 + V2 + V3;
+
+  /* Check if there is a (numerically stable) solution */
+  if (fabs(V) * 1.0e10 <= -V1 + V2 + fabs(V3))
+    return 0;
+
+  *b2 = U / V;
+
+  return 1;
+}
--- a/regress.h
+++ b/regress.h
@@ -119,4 +119,19 @@ RGR_FindBestRobustRegression
 int *n_runs,
 int *best_start);

+int
+RGR_MultipleRegress
+(double *x1,                    /* first independent variable */
+ double *x2,                    /* second independent variable */
+ double *y,                     /* measured data */
+
+ int n,                         /* number of data points */
+
+ /* The results */
+ double *b2                     /* estimated second slope */
+);
+
+/* Return the median value from an array */
+extern double RGR_FindMedian(double *x, int n);
+
 #endif /* GOT_REGRESS_H */
--- a/reports.h
+++ b/reports.h
@@ -31,8 +31,6 @@
 #include "addressing.h"
 #include "ntp.h"

-#define REPORT_INVALID_OFFSET 0x80000000
-
 typedef struct {
  IPAddr ip_addr;
  int stratum;
@@ -53,7 +51,7 @@ typedef struct {
  IPAddr ip_addr;
  int stratum;
  NTP_Leap leap_status;
-  struct timeval ref_time;
+  struct timespec ref_time;
  double current_correction;
  double last_offset;
  double rms_offset;
@@ -79,7 +77,7 @@ typedef struct {
 } RPT_SourcestatsReport;

 typedef struct {
-  struct timeval ref_time;
+  struct timespec ref_time;
  unsigned short n_samples;
  unsigned short n_runs;
  unsigned long span_seconds;
@@ -109,7 +107,7 @@ typedef struct {
 } RPT_ServerStatsReport;

 typedef struct {
-  struct timeval when;
+  struct timespec when;
  double slewed_offset;
  double orig_offset;
  double residual;
@@ -133,4 +131,33 @@ typedef struct {
  double remaining_time;
 } RPT_SmoothingReport;

+typedef struct {
+  IPAddr remote_addr;
+  IPAddr local_addr;
+  uint16_t remote_port;
+  uint8_t leap;
+  uint8_t version;
+  uint8_t mode;
+  uint8_t stratum;
+  int8_t poll;
+  int8_t precision;
+  double root_delay;
+  double root_dispersion;
+  uint32_t ref_id;
+  struct timespec ref_time;
+  double offset;
+  double peer_delay;
+  double peer_dispersion;
+  double response_time;
+  double jitter_asymmetry;
+  uint16_t tests;
+  int interleaved;
+  int authenticated;
+  char tx_tss_char;
+  char rx_tss_char;
+  uint32_t total_tx_count;
+  uint32_t total_rx_count;
+  uint32_t total_valid_count;
+} RPT_NTPReport;
+
 #endif /* GOT_REPORTS_H */
--- a/rtc.c
+++ b/rtc.c
@@ -98,13 +98,13 @@ get_driftfile_time(void)
 static void
 apply_driftfile_time(time_t t)
 {
-  struct timeval now;
+  struct timespec now;

  LCL_ReadCookedTime(&now, NULL);

  if (now.tv_sec < t) {
    if (LCL_ApplyStepOffset(now.tv_sec - t))
-      LOG(LOGS_INFO, LOGF_Rtc, "System time restored from driftfile");
+      LOG(LOGS_INFO, "System time restored from driftfile");
  }
 }

@@ -142,7 +142,7 @@ RTC_Initialise(int initial_set)

  if (file_name) {
    if (CNF_GetRtcSync()) {
-      LOG_FATAL(LOGF_Rtc, "rtcfile directive cannot be used with rtcsync");
+      LOG_FATAL("rtcfile directive cannot be used with rtcsync");
    }

    if (driver.init) {
@@ -150,7 +150,7 @@ RTC_Initialise(int initial_set)
        driver_initialised = 1;
      }
    } else {
-      LOG(LOGS_ERR, LOGF_Rtc, "RTC not supported on this operating system");
+      LOG(LOGS_ERR, "RTC not supported on this operating system");
    }
  }
 }
@@ -160,7 +160,7 @@ RTC_Initialise(int initial_set)
 void
 RTC_Finalise(void)
 {
-  if (driver.fini) {
+  if (driver_initialised) {
    (driver.fini)();
  }
 }
--- a/rtc_linux.c
+++ b/rtc_linux.c
@@ -50,7 +50,7 @@

 static void measurement_timeout(void *any);

-static void read_from_device(void *any);
+static void read_from_device(int fd_, int event, void *any);

 /* ================================================== */

@@ -92,9 +92,8 @@ static double *rtc_trim = NULL;
 static time_t rtc_ref;


-/* System clock (gettimeofday) samples associated with the above
-   samples. */
-static struct timeval *system_times = NULL;
+/* System clock samples associated with the above samples. */
+static struct timespec *system_times = NULL;

 /* Number of samples currently stored. */
 static int n_samples;   
@@ -170,7 +169,7 @@ discard_samples(int new_first)

  memmove(rtc_sec, rtc_sec + new_first, n_to_save * sizeof(time_t));
  memmove(rtc_trim, rtc_trim + new_first, n_to_save * sizeof(double));
-  memmove(system_times, system_times + new_first, n_to_save * sizeof(struct timeval));
+  memmove(system_times, system_times + new_first, n_to_save * sizeof(struct timespec));

  n_samples = n_to_save;
 }
@@ -180,7 +179,7 @@ discard_samples(int new_first)
 #define NEW_FIRST_WHEN_FULL 4

 static void
-accumulate_sample(time_t rtc, struct timeval *sys)
+accumulate_sample(time_t rtc, struct timespec *sys)
 {

  if (n_samples == MAX_SAMPLES) {
@@ -188,6 +187,11 @@ accumulate_sample(time_t rtc, struct timeval *sys)
    discard_samples(NEW_FIRST_WHEN_FULL);
  }

+  /* Discard all samples if the RTC was stepped back (not our trim) */
+  if (n_samples > 0 && rtc_sec[n_samples - 1] - rtc >= rtc_trim[n_samples - 1]) {
+    DEBUG_LOG("RTC samples discarded");
+    n_samples = 0;
+  }

  /* Always use most recent sample as reference */
  /* use sample only if n_sample is not negative*/
@@ -225,7 +229,7 @@ run_regression(int new_sample,
    for (i=0; i<n_samples; i++) {
      rtc_rel[i] = rtc_trim[i] + (double)(rtc_sec[i] - rtc_ref);
      offsets[i] = ((double) (rtc_ref - system_times[i].tv_sec) -
-                    (1.0e-6 * (double) system_times[i].tv_usec) +
+                    (1.0e-9 * system_times[i].tv_nsec) +
                    rtc_rel[i]);

    }
@@ -262,7 +266,7 @@ run_regression(int new_sample,

 static void
 slew_samples
-(struct timeval *raw, struct timeval *cooked,
+(struct timespec *raw, struct timespec *cooked,
 double dfreq,
 double doffset,
 LCL_ChangeType change_type,
@@ -278,7 +282,7 @@ slew_samples
  }

  for (i=0; i<n_samples; i++) {
-    UTI_AdjustTimeval(system_times + i, cooked, system_times + i, &delta_time,
+    UTI_AdjustTimespec(system_times + i, cooked, system_times + i, &delta_time,
        dfreq, doffset);
  }

@@ -290,7 +294,7 @@ slew_samples
    coef_gain_rate += dfreq * (1.0 - coef_gain_rate);
  }

-  DEBUG_LOG(LOGF_RtcLinux, "dfreq=%.8f doffset=%.6f old_fast=%.6f old_rate=%.3f new_fast=%.6f new_rate=%.3f",
+  DEBUG_LOG("dfreq=%.8f doffset=%.6f old_fast=%.6f old_rate=%.3f new_fast=%.6f new_rate=%.3f",
      dfreq, doffset,
      old_seconds_fast, 1.0e6 * old_gain_rate,
      coef_seconds_fast, 1.0e6 * coef_gain_rate);
@@ -348,7 +352,7 @@ rtc_from_t(const time_t *t)

 static time_t
 t_from_rtc(struct tm *stm) {
-  struct tm temp1, temp2;
+  struct tm temp1, temp2, *tm;
  long diff;
  time_t t1, t2;

@@ -356,18 +360,20 @@ t_from_rtc(struct tm *stm) {
  temp1.tm_isdst = 0;
  
  t1 = mktime(&temp1);
-  if (rtc_on_utc) {
-    temp2 = *gmtime(&t1);
-  } else {
-    temp2 = *localtime(&t1);
+
+  tm = rtc_on_utc ? gmtime(&t1) : localtime(&t1);
+  if (!tm) {
+    DEBUG_LOG("gmtime()/localtime() failed");
+    return -1;
  }
-  
+
+  temp2 = *tm;
  temp2.tm_isdst = 0;
  t2 = mktime(&temp2);
  diff = t2 - t1;

  if (t1 - diff == -1)
-    DEBUG_LOG(LOGF_RtcLinux, "Could not convert RTC time");
+    DEBUG_LOG("Could not convert RTC time");

  return t1 - diff;
 }
@@ -384,12 +390,9 @@ read_hwclock_file(const char *hwclock_file)
  if (!hwclock_file || !hwclock_file[0])
    return;

-  in = fopen(hwclock_file, "r");
-  if (!in) {
-    LOG(LOGS_WARN, LOGF_RtcLinux, "Could not open %s : %s",
-        hwclock_file, strerror(errno));
+  in = UTI_OpenFile(NULL, hwclock_file, NULL, 'r', 0);
+  if (!in)
    return;
-  }

  /* Read third line from the file. */
  for (i = 0; i < 3; i++) {
@@ -404,8 +407,7 @@ read_hwclock_file(const char *hwclock_file)
  } else if (i == 3 && !strncmp(line, "UTC", 3)) {
    rtc_on_utc = 1;
  } else {
-    LOG(LOGS_WARN, LOGF_RtcLinux, "Could not read RTC LOCAL/UTC setting from %s",
-        hwclock_file);
+    LOG(LOGS_WARN, "Could not read RTC LOCAL/UTC setting from %s", hwclock_file);
  }
 }

@@ -440,15 +442,15 @@ read_coefs_from_file(void)

    tried_to_load_coefs = 1;

-    if (coefs_file_name && (in = fopen(coefs_file_name, "r"))) {
+    if (coefs_file_name &&
+        (in = UTI_OpenFile(NULL, coefs_file_name, NULL, 'r', 0))) {
      if (fscanf(in, "%d%ld%lf%lf",
                 &valid_coefs_from_file,
                 &file_ref_time,
                 &file_ref_offset,
                 &file_rate_ppm) == 4) {
      } else {
-        LOG(LOGS_WARN, LOGF_RtcLinux, "Could not read coefficients from %s",
-            coefs_file_name);
+        LOG(LOGS_WARN, "Could not read coefficients from %s", coefs_file_name);
      }
      fclose(in);
    }
@@ -462,67 +464,40 @@ read_coefs_from_file(void)
 static int
 write_coefs_to_file(int valid,time_t ref_time,double offset,double rate)
 {
-  struct stat buf;
-  char *temp_coefs_file_name;
  FILE *out;
-  int r1, r2;

  /* Create a temporary file with a '.tmp' extension. */
-
-  temp_coefs_file_name = (char*) Malloc(strlen(coefs_file_name)+8);
-
-  if(!temp_coefs_file_name) {
+  out = UTI_OpenFile(NULL, coefs_file_name, ".tmp", 'w', 0644);
+  if (!out)
    return RTC_ST_BADFILE;
-  }
-
-  strcpy(temp_coefs_file_name,coefs_file_name);
-  strcat(temp_coefs_file_name,".tmp");
-
-  out = fopen(temp_coefs_file_name, "w");
-  if (!out) {
-    Free(temp_coefs_file_name);
-    LOG(LOGS_WARN, LOGF_RtcLinux, "Could not open temporary RTC file %s.tmp for writing",
-        coefs_file_name);
-    return RTC_ST_BADFILE;
-  }

  /* Gain rate is written out in ppm */
-  r1 = fprintf(out, "%1d %ld %.6f %.3f\n",
-               valid, ref_time, offset, 1.0e6 * rate);
-  r2 = fclose(out);
-  if (r1 < 0 || r2) {
-    Free(temp_coefs_file_name);
-    LOG(LOGS_WARN, LOGF_RtcLinux, "Could not write to temporary RTC file %s.tmp",
-        coefs_file_name);
+  fprintf(out, "%1d %ld %.6f %.3f\n", valid, ref_time, offset, 1.0e6 * rate);
+  fclose(out);
+
+  /* Rename the temporary file to the correct location */
+  if (!UTI_RenameTempFile(NULL, coefs_file_name, ".tmp", NULL))
    return RTC_ST_BADFILE;
-  }
-
-  /* Clone the file attributes from the existing file if there is one. */
-
-  if (!stat(coefs_file_name,&buf)) {
-    if (chown(temp_coefs_file_name,buf.st_uid,buf.st_gid) ||
-        chmod(temp_coefs_file_name,buf.st_mode & 0777)) {
-      LOG(LOGS_WARN, LOGF_RtcLinux,
-          "Could not change ownership or permissions of temporary RTC file %s.tmp",
-          coefs_file_name);
-    }
-  }
-
-  /* Rename the temporary file to the correct location (see rename(2) for details). */
-
-  if (rename(temp_coefs_file_name,coefs_file_name)) {
-    unlink(temp_coefs_file_name);
-    Free(temp_coefs_file_name);
-    LOG(LOGS_WARN, LOGF_RtcLinux, "Could not replace old RTC file %s.tmp with new one %s",
-        coefs_file_name, coefs_file_name);
-    return RTC_ST_BADFILE;
-  }
-
-  Free(temp_coefs_file_name);

  return RTC_ST_OK;
 }

+/* ================================================== */
+
+static int
+switch_interrupts(int on_off)
+{
+  if (ioctl(fd, on_off ? RTC_UIE_ON : RTC_UIE_OFF, 0) < 0) {
+    LOG(LOGS_ERR, "Could not %s RTC interrupt : %s",
+        on_off ? "enable" : "disable", strerror(errno));
+    return 0;
+  }
+
+  if (on_off)
+    skip_interrupts = 1;
+
+  return 1;
+}

 /* ================================================== */
 /* file_name is the name of the file where we save the RTC params
@@ -532,9 +507,26 @@ write_coefs_to_file(int valid,time_t ref_time,double offset,double rate)
 int
 RTC_Linux_Initialise(void)
 {
+  /* Try to open the device */
+  fd = open(CNF_GetRtcDevice(), O_RDWR);
+  if (fd < 0) {
+    LOG(LOGS_ERR, "Could not open RTC device %s : %s",
+        CNF_GetRtcDevice(), strerror(errno));
+    return 0;
+  }
+
+  /* Make sure the RTC supports interrupts */
+  if (!switch_interrupts(1) || !switch_interrupts(0)) {
+    close(fd);
+    return 0;
+  }
+
+  /* Close on exec */
+  UTI_FdSetCloexec(fd);
+
  rtc_sec = MallocArray(time_t, MAX_SAMPLES);
  rtc_trim = MallocArray(double, MAX_SAMPLES);
-  system_times = MallocArray(struct timeval, MAX_SAMPLES);
+  system_times = MallocArray(struct timespec, MAX_SAMPLES);

  /* Setup details depending on configuration options */
  setup_config();
@@ -542,18 +534,6 @@ RTC_Linux_Initialise(void)
  /* In case it didn't get done by pre-init */
  coefs_file_name = CNF_GetRtcFile();

-  /* Try to open device */
-
-  fd = open (CNF_GetRtcDevice(), O_RDWR);
-  if (fd < 0) {
-    LOG(LOGS_ERR, LOGF_RtcLinux, "Could not open RTC device %s : %s",
-        CNF_GetRtcDevice(), strerror(errno));
-    return 0;
-  }
-
-  /* Close on exec */
-  UTI_FdSetCloexec(fd);
-
  n_samples = 0;
  n_samples_since_regression = 0;
  n_runs = 0;
@@ -564,7 +544,7 @@ RTC_Linux_Initialise(void)
  operating_mode = OM_NORMAL;

  /* Register file handler */
-  SCH_AddInputFileHandler(fd, read_from_device, NULL);
+  SCH_AddFileHandler(fd, SCH_FILE_INPUT, read_from_device, NULL);

  /* Register slew handler */
  LCL_AddParameterChangeHandler(slew_samples, NULL);
@@ -585,7 +565,8 @@ RTC_Linux_Finalise(void)

  /* Remove input file handler */
  if (fd >= 0) {
-    SCH_RemoveInputFileHandler(fd);
+    SCH_RemoveFileHandler(fd);
+    switch_interrupts(0);
    close(fd);

    /* Save the RTC data */
@@ -599,31 +580,6 @@ RTC_Linux_Finalise(void)

 /* ================================================== */

-static void
-switch_interrupts(int onoff)
-{
-  int status;
-
-  if (onoff) {
-    status = ioctl(fd, RTC_UIE_ON, 0);
-    if (status < 0) {
-      LOG(LOGS_ERR, LOGF_RtcLinux, "Could not %s RTC interrupt : %s",
-          "enable", strerror(errno));
-      return;
-    }
-    skip_interrupts = 1;
-  } else {
-    status = ioctl(fd, RTC_UIE_OFF, 0);
-    if (status < 0) {
-      LOG(LOGS_ERR, LOGF_RtcLinux, "Could not %s RTC interrupt : %s",
-          "disable", strerror(errno));
-      return;
-    }
-  }
-}    
-
-/* ================================================== */
-
 static void
 measurement_timeout(void *any)
 {
@@ -654,7 +610,7 @@ set_rtc(time_t new_rtc_time)

  status = ioctl(fd, RTC_SET_TIME, &rtc_raw);
  if (status < 0) {
-    LOG(LOGS_ERR, LOGF_RtcLinux, "Could not set RTC time");
+    LOG(LOGS_ERR, "Could not set RTC time");
  }

 }
@@ -697,10 +653,10 @@ handle_initial_trim(void)
    sys_error_now = rtc_error_now - coef_seconds_fast;
          
    LCL_AccumulateOffset(sys_error_now, 0.0);
-    LOG(LOGS_INFO, LOGF_RtcLinux, "System clock off from RTC by %f seconds (slew)",
+    LOG(LOGS_INFO, "System clock off from RTC by %f seconds (slew)",
        sys_error_now);
  } else {
-    LOG(LOGS_WARN, LOGF_RtcLinux, "No valid rtcfile coefficients");
+    LOG(LOGS_WARN, "No valid rtcfile coefficients");
  }
  
  coefs_valid = 0;
@@ -725,7 +681,7 @@ handle_relock_after_trim(void)
  if (valid) {
    write_coefs_to_file(1,ref,fast,saved_coef_gain_rate);
  } else {
-    DEBUG_LOG(LOGF_RtcLinux, "Could not do regression after trim");
+    DEBUG_LOG("Could not do regression after trim");
  }

  coefs_valid = 0;
@@ -758,7 +714,7 @@ maybe_autotrim(void)
 /* ================================================== */

 static void
-process_reading(time_t rtc_time, struct timeval *system_time)
+process_reading(time_t rtc_time, struct timespec *system_time)
 {
  double rtc_fast;

@@ -791,7 +747,7 @@ process_reading(time_t rtc_time, struct timeval *system_time)


  if (logfileid != -1) {
-    rtc_fast = (double)(rtc_time - system_time->tv_sec) - 1.0e-6 * (double) system_time->tv_usec;
+    rtc_fast = (rtc_time - system_time->tv_sec) - 1.0e-9 * system_time->tv_nsec;

    LOG_FileWrite(logfileid, "%s %14.6f %1d  %14.6f  %12.3f  %2d  %2d %4d",
            UTI_TimeToLogForm(system_time->tv_sec),
@@ -805,11 +761,11 @@ process_reading(time_t rtc_time, struct timeval *system_time)
 /* ================================================== */

 static void
-read_from_device(void *any)
+read_from_device(int fd_, int event, void *any)
 {
  int status;
  unsigned long data;
-  struct timeval sys_time;
+  struct timespec sys_time;
  struct rtc_time rtc_raw;
  struct tm rtc_tm;
  time_t rtc_t;
@@ -820,8 +776,8 @@ read_from_device(void *any)
  if (status < 0) {
    /* This looks like a bad error : the file descriptor was indicating it was
     * ready to read but we couldn't read anything.  Give up. */
-    LOG(LOGS_ERR, LOGF_RtcLinux, "Could not read flags %s : %s", CNF_GetRtcDevice(), strerror(errno));
-    SCH_RemoveInputFileHandler(fd);
+    LOG(LOGS_ERR, "Could not read flags %s : %s", CNF_GetRtcDevice(), strerror(errno));
+    SCH_RemoveFileHandler(fd);
    switch_interrupts(0); /* Likely to raise error too, but just to be sure... */
    close(fd);
    fd = -1;
@@ -844,12 +800,12 @@ read_from_device(void *any)

    status = ioctl(fd, RTC_RD_TIME, &rtc_raw);
    if (status < 0) {
-      LOG(LOGS_ERR, LOGF_RtcLinux, "Could not read time from %s : %s", CNF_GetRtcDevice(), strerror(errno));
+      LOG(LOGS_ERR, "Could not read time from %s : %s", CNF_GetRtcDevice(), strerror(errno));
      error = 1;
      goto turn_off_interrupt;
    }

-    /* Convert RTC time into a struct timeval */
+    /* Convert RTC time into a struct timespec */
    rtc_tm.tm_sec = rtc_raw.tm_sec;
    rtc_tm.tm_min = rtc_raw.tm_min;
    rtc_tm.tm_hour = rtc_raw.tm_hour;
@@ -885,7 +841,7 @@ turn_off_interrupt:
  switch (operating_mode) {
    case OM_INITIAL:
      if (error) {
-        DEBUG_LOG(LOGF_RtcLinux, "Could not complete initial step due to errors");
+        DEBUG_LOG("Could not complete initial step due to errors");
        operating_mode = OM_NORMAL;
        (after_init_hook)(after_init_hook_arg);

@@ -898,7 +854,7 @@ turn_off_interrupt:

    case OM_AFTERTRIM:
      if (error) {
-        DEBUG_LOG(LOGF_RtcLinux, "Could not complete after trim relock due to errors");
+        DEBUG_LOG("Could not complete after trim relock due to errors");
        operating_mode = OM_NORMAL;

        switch_interrupts(0);
@@ -978,7 +934,7 @@ RTC_Linux_TimePreInit(time_t driftfile_time)
  struct tm rtc_tm;
  time_t rtc_t;
  double accumulated_error, sys_offset;
-  struct timeval new_sys_time, old_sys_time;
+  struct timespec new_sys_time, old_sys_time;

  coefs_file_name = CNF_GetRtcFile();

@@ -1032,21 +988,21 @@ RTC_Linux_TimePreInit(time_t driftfile_time)

      new_sys_time.tv_sec = rtc_t;
      /* Average error in the RTC reading */
-      new_sys_time.tv_usec = 500000;
+      new_sys_time.tv_nsec = 500000000;

-      UTI_AddDoubleToTimeval(&new_sys_time, -accumulated_error, &new_sys_time);
+      UTI_AddDoubleToTimespec(&new_sys_time, -accumulated_error, &new_sys_time);

      if (new_sys_time.tv_sec < driftfile_time) {
-        LOG(LOGS_WARN, LOGF_RtcLinux, "RTC time before last driftfile modification (ignored)");
+        LOG(LOGS_WARN, "RTC time before last driftfile modification (ignored)");
        return 0;
      }

-      UTI_DiffTimevalsToDouble(&sys_offset, &old_sys_time, &new_sys_time);
+      sys_offset = UTI_DiffTimespecsToDouble(&old_sys_time, &new_sys_time);

      /* Set system time only if the step is larger than 1 second */
      if (fabs(sys_offset) >= 1.0) {
        if (LCL_ApplyStepOffset(sys_offset))
-          LOG(LOGS_INFO, LOGF_RtcLinux, "System time set from RTC");
+          LOG(LOGS_INFO, "System time set from RTC");
      }
    } else {
      return 0;
@@ -1064,7 +1020,7 @@ int
 RTC_Linux_GetReport(RPT_RTC_Report *report)
 {
  report->ref_time.tv_sec = coef_ref_time;
-  report->ref_time.tv_usec = 0;
+  report->ref_time.tv_nsec = 0;
  report->n_samples = n_samples;
  report->n_runs = n_runs;
  if (n_samples > 1) {
@@ -1083,8 +1039,7 @@ RTC_Linux_GetReport(RPT_RTC_Report *report)
 int
 RTC_Linux_Trim(void)
 {
-  struct timeval now;
-
+  struct timespec now;

  /* Remember the slope coefficient - we won't be able to determine a
     good one in a few seconds when we determine the new offset! */
@@ -1092,7 +1047,7 @@ RTC_Linux_Trim(void)

  if (fabs(coef_seconds_fast) > 1.0) {

-    LOG(LOGS_INFO, LOGF_RtcLinux, "RTC wrong by %.3f seconds (step)",
+    LOG(LOGS_INFO, "RTC wrong by %.3f seconds (step)",
        coef_seconds_fast);

    /* Do processing to set clock.  Let R be the value we set the
@@ -1114,7 +1069,7 @@ RTC_Linux_Trim(void)

    /* Estimate the offset in case writertc is called or chronyd
       is terminated during rapid sampling */
-    coef_seconds_fast = -now.tv_usec / 1e6 + 0.5;
+    coef_seconds_fast = -now.tv_nsec / 1.0e9 + 0.5;
    coef_ref_time = now.tv_sec;

    /* And start rapid sampling, interrupts on now */
--- a/Show More
+++ b/Show More