doc: update README

Handle zero NTP timestamp in UTI_Ntp64ToTimespec() as a special value to
make it symmetric with UTI_TimespecToNtp64(). This is needed since
commit d75f6830f1, in which a timestamp is
converted back and forth without checking for zero.

It also makes zero NTP timestamps more apparent in debug output.

README

@@ -16,7 +16,7 @@ and systems that do not run continuosly, or run on a virtual machine.
 
 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
+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
@@ -203,6 +203,9 @@ Kalle Olavi Niemitalo  <tosi@stekt.oulu.fi>
 Frank Otto <sandwichmacher@web.de>
     Handling arbitrary HZ values
 
+Denny Page <dennypage@me.com>
+    Advice on support for hardware timestamping
+
 Gautier PHILIPPON <gautier.philippon@ensimag.grenoble-inp.fr>
     Patch to add refresh command to chronyc
 

client.c

@@ -3,6 +3,7 @@
 
  **********************************************************************
  * Copyright (C) Richard P. Curnow  1997-2003
+ * Copyright (C) Lonnie Abelbeck  2016
  * Copyright (C) Miroslav Lichvar  2009-2016
  * 
  * This program is free software; you can redistribute it and/or modify
@@ -2723,7 +2724,8 @@ process_cmd_waitsync(char *line)
   max_skew_ppm = 0.0;
   interval = 10.0;
 
-  sscanf(line, "%d %lf %lf %lf", &max_tries, &max_correction, &max_skew_ppm, &interval);
+  if (sscanf(line, "%d %lf %lf %lf", &max_tries, &max_correction, &max_skew_ppm, &interval))
+    ;
 
   /* Don't allow shorter interval than 0.1 seconds */
   if (interval < 0.1)
@@ -2831,7 +2833,8 @@ process_cmd_keygen(char *line)
   snprintf(hash_name, sizeof (hash_name), "MD5");
 #endif
 
-  sscanf(line, "%u %16s %d", &id, hash_name, &bits);
+  if (sscanf(line, "%u %16s %d", &id, hash_name, &bits))
+    ;
 
   length = CLAMP(10, (bits + 7) / 8, sizeof (key));
   if (HSH_GetHashId(hash_name) < 0) {
@@ -3094,7 +3097,7 @@ static void
 display_gpl(void)
 {
     printf("chrony version %s\n"
-           "Copyright (C) 1997-2003, 2007, 2009-2016 Richard P. Curnow and others\n"
+           "Copyright (C) 1997-2003, 2007, 2009-2017 Richard P. Curnow and others\n"
            "chrony comes with ABSOLUTELY NO WARRANTY.  This is free software, and\n"
            "you are welcome to redistribute it under certain conditions.  See the\n"
            "GNU General Public License version 2 for details.\n\n",

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

configure

@@ -4,7 +4,8 @@
 # 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, 2012-2016
 #
 # =======================================================================
 

doc/chrony.conf.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
@@ -105,7 +106,7 @@ If the user knows that round trip delays above a certain level should cause the
 measurement to be ignored, this level can be defined with the *maxdelay*
 option. For example, *maxdelay 0.3* would indicate that measurements with a
 round-trip delay of 0.3 seconds or more should be ignored. The default value is
-3 seconds.
+3 seconds and the maximum value is 1000 seconds.
 *maxdelayratio* _ratio_:::
 This option is similar to the maxdelay option above. *chronyd* keeps a record
 of the minimum round-trip delay amongst the previous measurements that it has

doc/chronyc.adoc

@@ -1,6 +1,7 @@
 // This file is part of chrony
 //
 // Copyright (C) Richard P. Curnow  1997-2003
+// Copyright (C) Stephen Wadeley  2016
 // Copyright (C) Miroslav Lichvar  2009-2016
 //
 // This program is free software; you can redistribute it and/or modify

local.c

@@ -144,6 +144,8 @@ calculate_sys_precision(void)
     best *= 2;
   }
 
+  assert(precision_log >= -30);
+
   DEBUG_LOG(LOGF_Local, "Clock precision %.9f (%d)", precision_quantum, precision_log);
 }
 

main.c

@@ -325,7 +325,8 @@ 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

ntp_core.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
@@ -243,6 +243,11 @@ static ARR_Instance broadcasts;
 /* Maximum acceptable delay in transmission for timestamp correction */
 #define MAX_TX_DELAY 1.0
 
+/* Maximum allowed values of maxdelay parameters */
+#define MAX_MAX_DELAY 1.0e3
+#define MAX_MAX_DELAY_RATIO 1.0e6
+#define MAX_MAX_DELAY_DEV_RATIO 1.0e6
+
 /* Minimum and maximum allowed poll interval */
 #define MIN_POLL 0
 #define MAX_POLL 24
@@ -513,9 +518,9 @@ NCR_GetInstance(NTP_Remote_Address *remote_addr, NTP_Source_Type type, SourcePar
   if (result->presend_minpoll <= MAX_POLL && result->mode != MODE_CLIENT)
     result->presend_minpoll = MAX_POLL + 1;
 
-  result->max_delay = params->max_delay;
-  result->max_delay_ratio = params->max_delay_ratio;
-  result->max_delay_dev_ratio = params->max_delay_dev_ratio;
+  result->max_delay = CLAMP(0.0, params->max_delay, MAX_MAX_DELAY);
+  result->max_delay_ratio = CLAMP(0.0, params->max_delay_ratio, MAX_MAX_DELAY_RATIO);
+  result->max_delay_dev_ratio = CLAMP(0.0, params->max_delay_dev_ratio, MAX_MAX_DELAY_DEV_RATIO);
   result->offset_correction = params->offset;
   result->auto_offline = params->auto_offline;
   result->poll_target = params->poll_target;
@@ -951,57 +956,63 @@ transmit_packet(NTP_Mode my_mode, /* The mode this machine wants to be */
      frequency all along */
   UTI_TimespecToNtp64(&local_receive, &message.receive_ts, &ts_fuzz);
 
-  /* Prepare random bits which will be added to the transmit timestamp. */
-  UTI_GetNtp64Fuzz(&ts_fuzz, precision);
+  do {
+    /* Prepare random bits which will be added to the transmit timestamp */
+    UTI_GetNtp64Fuzz(&ts_fuzz, precision);
 
-  /* Transmit - this our local time right now!  Also, we might need to
-     store this for our own use later, next time we receive a message
-     from the source we're sending to now. */
-  LCL_ReadCookedTime(&local_transmit, &local_transmit_err);
+    /* Transmit - this our local time right now!  Also, we might need to
+       store this for our own use later, next time we receive a message
+       from the source we're sending to now. */
+    LCL_ReadCookedTime(&local_transmit, &local_transmit_err);
 
-  if (smooth_time)
-    UTI_AddDoubleToTimespec(&local_transmit, smooth_offset, &local_transmit);
+    if (smooth_time)
+      UTI_AddDoubleToTimespec(&local_transmit, smooth_offset, &local_transmit);
 
-  length = NTP_NORMAL_PACKET_LENGTH;
+    length = NTP_NORMAL_PACKET_LENGTH;
 
-  /* Authenticate the packet if needed */
+    /* Authenticate the packet */
 
-  if (auth_mode == AUTH_SYMMETRIC || auth_mode == AUTH_MSSNTP) {
-    /* Pre-compensate the transmit time by approx. how long it will
-       take to generate the authentication data. */
-    local_transmit.tv_nsec += auth_mode == AUTH_SYMMETRIC ?
-                              KEY_GetAuthDelay(key_id) : NSD_GetAuthDelay(key_id);
-    UTI_NormaliseTimespec(&local_transmit);
-    UTI_TimespecToNtp64(interleaved ? &local_tx->ts : &local_transmit,
-                        &message.transmit_ts, &ts_fuzz);
+    if (auth_mode == AUTH_SYMMETRIC || auth_mode == AUTH_MSSNTP) {
+      /* Pre-compensate the transmit time by approximately how long it will
+         take to generate the authentication data */
+      local_transmit.tv_nsec += auth_mode == AUTH_SYMMETRIC ?
+                                KEY_GetAuthDelay(key_id) : NSD_GetAuthDelay(key_id);
+      UTI_NormaliseTimespec(&local_transmit);
+      UTI_TimespecToNtp64(interleaved ? &local_tx->ts : &local_transmit,
+                          &message.transmit_ts, &ts_fuzz);
 
-    if (auth_mode == AUTH_SYMMETRIC) {
-      auth_len = KEY_GenerateAuth(key_id, (unsigned char *) &message,
-                                  offsetof(NTP_Packet, auth_keyid),
-                                  (unsigned char *)&message.auth_data,
-                                  sizeof (message.auth_data));
-      if (!auth_len) {
-        DEBUG_LOG(LOGF_NtpCore, "Could not generate auth data with key %"PRIu32, key_id);
-        return 0;
+      if (auth_mode == AUTH_SYMMETRIC) {
+        auth_len = KEY_GenerateAuth(key_id, (unsigned char *) &message,
+                                    offsetof(NTP_Packet, auth_keyid),
+                                    (unsigned char *)&message.auth_data,
+                                    sizeof (message.auth_data));
+        if (!auth_len) {
+          DEBUG_LOG(LOGF_NtpCore, "Could not generate auth data with key %"PRIu32, key_id);
+          return 0;
+        }
+
+        message.auth_keyid = htonl(key_id);
+        mac_len = sizeof (message.auth_keyid) + auth_len;
+
+        /* Truncate MACs in NTPv4 packets to allow deterministic parsing
+           of extension fields (RFC 7822) */
+        if (version == 4 && mac_len > NTP_MAX_V4_MAC_LENGTH)
+          mac_len = NTP_MAX_V4_MAC_LENGTH;
+
+        length += mac_len;
+      } else if (auth_mode == AUTH_MSSNTP) {
+        /* MS-SNTP packets are signed (asynchronously) by ntp_signd */
+        return NSD_SignAndSendPacket(key_id, &message, where_to, from, length);
       }
-
-      message.auth_keyid = htonl(key_id);
-      mac_len = sizeof (message.auth_keyid) + auth_len;
-
-      /* Truncate MACs in NTPv4 packets to allow deterministic parsing
-         of extension fields (RFC 7822) */
-      if (version == 4 && mac_len > NTP_MAX_V4_MAC_LENGTH)
-        mac_len = NTP_MAX_V4_MAC_LENGTH;
-
-      length += mac_len;
-    } else if (auth_mode == AUTH_MSSNTP) {
-      /* MS-SNTP packets are signed (asynchronously) by ntp_signd */
-      return NSD_SignAndSendPacket(key_id, &message, where_to, from, length);
+    } else {
+      UTI_TimespecToNtp64(interleaved ? &local_tx->ts : &local_transmit,
+                          &message.transmit_ts, &ts_fuzz);
     }
-  } else {
-    UTI_TimespecToNtp64(interleaved ? &local_tx->ts : &local_transmit,
-                        &message.transmit_ts, &ts_fuzz);
-  }
+
+    /* Avoid sending messages with non-zero transmit timestamp equal to the
+       receive timestamp to allow reliable detection of the interleaved mode */
+  } while (!UTI_CompareNtp64(&message.transmit_ts, &message.receive_ts) &&
+           !UTI_IsZeroNtp64(&message.transmit_ts));
 
   ret = NIO_SendPacket(&message, where_to, from, length, local_tx != NULL);
 
@@ -2106,9 +2117,9 @@ NCR_ModifyMaxpoll(NCR_Instance inst, int new_maxpoll)
 void
 NCR_ModifyMaxdelay(NCR_Instance inst, double new_max_delay)
 {
-  inst->max_delay = new_max_delay;
+  inst->max_delay = CLAMP(0.0, new_max_delay, MAX_MAX_DELAY);
   LOG(LOGS_INFO, LOGF_NtpCore, "Source %s new max delay %f",
-      UTI_IPToString(&inst->remote_addr.ip_addr), new_max_delay);
+      UTI_IPToString(&inst->remote_addr.ip_addr), inst->max_delay);
 }
 
 /* ================================================== */
@@ -2116,9 +2127,9 @@ NCR_ModifyMaxdelay(NCR_Instance inst, double new_max_delay)
 void
 NCR_ModifyMaxdelayratio(NCR_Instance inst, double new_max_delay_ratio)
 {
-  inst->max_delay_ratio = new_max_delay_ratio;
+  inst->max_delay_ratio = CLAMP(0.0, new_max_delay_ratio, MAX_MAX_DELAY_RATIO);
   LOG(LOGS_INFO, LOGF_NtpCore, "Source %s new max delay ratio %f",
-      UTI_IPToString(&inst->remote_addr.ip_addr), new_max_delay_ratio);
+      UTI_IPToString(&inst->remote_addr.ip_addr), inst->max_delay_ratio);
 }
 
 /* ================================================== */
@@ -2126,9 +2137,9 @@ NCR_ModifyMaxdelayratio(NCR_Instance inst, double new_max_delay_ratio)
 void
 NCR_ModifyMaxdelaydevratio(NCR_Instance inst, double new_max_delay_dev_ratio)
 {
-  inst->max_delay_dev_ratio = new_max_delay_dev_ratio;
+  inst->max_delay_dev_ratio = CLAMP(0.0, new_max_delay_dev_ratio, MAX_MAX_DELAY_DEV_RATIO);
   LOG(LOGS_INFO, LOGF_NtpCore, "Source %s new max delay dev ratio %f",
-      UTI_IPToString(&inst->remote_addr.ip_addr), new_max_delay_dev_ratio);
+      UTI_IPToString(&inst->remote_addr.ip_addr), inst->max_delay_dev_ratio);
 }
 
 /* ================================================== */

ntp_io_linux.c

@@ -2,7 +2,7 @@
   chronyd/chronyc - Programs for keeping computer clocks accurate.
 
  **********************************************************************
- * Copyright (C) Miroslav Lichvar  2016
+ * Copyright (C) Miroslav Lichvar  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

rtc_linux.c

@@ -187,6 +187,11 @@ accumulate_sample(time_t rtc, struct timespec *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(LOGF_RtcLinux, "RTC samples discarded");
+    n_samples = 0;
+  }
 
   /* Always use most recent sample as reference */
   /* use sample only if n_sample is not negative*/

sourcestats.c

@@ -928,7 +928,7 @@ void
 SST_DoSourceReport(SST_Stats inst, RPT_SourceReport *report, struct timespec *now)
 {
   int i, j;
-  struct timespec ago;
+  struct timespec last_sample_time;
 
   if (inst->n_samples > 0) {
     i = get_runsbuf_index(inst, inst->n_samples - 1);
@@ -938,8 +938,10 @@ SST_DoSourceReport(SST_Stats inst, RPT_SourceReport *report, struct timespec *no
     report->latest_meas_err = 0.5*inst->root_delays[j] + inst->root_dispersions[j];
     report->stratum = inst->strata[j];
 
-    UTI_DiffTimespecs(&ago, now, &inst->sample_times[i]);
-    report->latest_meas_ago = ago.tv_sec;
+    /* Align the sample time to reduce the leak of the receive timestamp */
+    last_sample_time = inst->sample_times[i];
+    last_sample_time.tv_nsec = 0;
+    report->latest_meas_ago = UTI_DiffTimespecsToDouble(now, &last_sample_time);
   } else {
     report->latest_meas_ago = (uint32_t)-1;
     report->orig_latest_meas = 0;

sys_timex.c

@@ -158,7 +158,8 @@ set_sync_status(int synchronised, double est_error, double max_error)
   txc.esterror = est_error * 1.0e6;
   txc.maxerror = max_error * 1.0e6;
 
-  SYS_Timex_Adjust(&txc, 1);
+  if (SYS_Timex_Adjust(&txc, 1) < 0)
+    ;
 }
 
 /* ================================================== */

test/simulation/119-smoothtime

@@ -25,7 +25,7 @@ time_offset=-10
 client_server_options="minpoll 6 maxpoll 6"
 client_conf="corrtimeratio 100"
 min_sync_time=8000
-max_sync_time=8500
+max_sync_time=9000
 
 run_test || test_fail
 check_chronyd_exit || test_fail

test/unit/ntp_core.c

@@ -0,0 +1,296 @@
+/*
+ **********************************************************************
+ * 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
+ * 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.
+ * 
+ **********************************************************************
+ */
+
+#include <config.h>
+#include <sysincl.h>
+#include <cmdparse.h>
+#include <conf.h>
+#include <keys.h>
+#include <ntp_io.h>
+#include <sched.h>
+#include <local.h>
+#include "test.h"
+
+static struct timespec current_time;
+static NTP_Receive_Buffer req_buffer, res_buffer;
+static int req_length, res_length;
+
+#define NIO_OpenServerSocket(addr) ((addr)->ip_addr.family != IPADDR_UNSPEC ? 100 : 0)
+#define NIO_CloseServerSocket(fd) assert(fd == 100)
+#define NIO_OpenClientSocket(addr) ((addr)->ip_addr.family != IPADDR_UNSPEC ? 101 : 0)
+#define NIO_CloseClientSocket(fd) assert(fd == 101)
+#define NIO_SendPacket(msg, to, from, len, process_tx) (memcpy(&req_buffer, msg, len), req_length = len, 1)
+#define SCH_AddTimeoutByDelay(delay, handler, arg) (1 ? 102 : (handler(arg), 1))
+#define SCH_AddTimeoutInClass(delay, separation, randomness, class, handler, arg) \
+  add_timeout_in_class(delay, separation, randomness, class, handler, arg)
+#define SCH_RemoveTimeout(id) assert(!id || id == 102)
+#define LCL_ReadRawTime(ts) (*ts = current_time)
+#define LCL_ReadCookedTime(ts, err) do {double *p = err; *ts = current_time; if (p) *p = 0.0;} while (0)
+#define SRC_UpdateReachability(inst, reach)
+#define SRC_ResetReachability(inst)
+
+static SCH_TimeoutID
+add_timeout_in_class(double min_delay, double separation, double randomness,
+                     SCH_TimeoutClass class, SCH_TimeoutHandler handler, SCH_ArbitraryArgument arg)
+{
+  return 102;
+}
+
+#include <ntp_core.c>
+
+static NCR_Instance inst;
+
+static void
+advance_time(double x)
+{
+  UTI_AddDoubleToTimespec(&current_time, x, &current_time);
+}
+
+static void
+send_request(void)
+{
+  NTP_Local_Address local_addr;
+  NTP_Local_Timestamp local_ts;
+  uint32_t prev_tx_count;
+
+  prev_tx_count = inst->report.total_tx_count;
+
+  transmit_timeout(inst);
+  TEST_CHECK(!inst->valid_rx);
+  TEST_CHECK(!inst->updated_timestamps);
+  TEST_CHECK(prev_tx_count + 1 == inst->report.total_tx_count);
+
+  advance_time(1e-4);
+
+  local_addr.ip_addr.family = IPADDR_UNSPEC;
+  local_addr.sock_fd = 101;
+  local_ts.ts = current_time;
+  local_ts.err = 0.0;
+  local_ts.source = NTP_TS_DAEMON;
+
+  NCR_ProcessTxKnown(inst, &local_addr, &local_ts, &req_buffer.ntp_pkt, req_length);
+}
+
+static void
+send_response(int interleaved, int authenticated, int allow_update, int valid_ts, int valid_auth)
+{
+  NTP_Packet *req, *res;
+
+  req = &req_buffer.ntp_pkt;
+  res = &res_buffer.ntp_pkt;
+
+  TEST_CHECK(req_length >= NTP_NORMAL_PACKET_LENGTH);
+
+  res->lvm = NTP_LVM(LEAP_Normal, NTP_LVM_TO_VERSION(req->lvm),
+                     NTP_LVM_TO_MODE(req->lvm) == MODE_CLIENT ? MODE_SERVER : MODE_ACTIVE);
+  res->stratum = 1;
+  res->poll = req->poll;
+  res->precision = -20;
+  res->root_delay = UTI_DoubleToNtp32(0.1);
+  res->root_dispersion = UTI_DoubleToNtp32(0.1);
+  res->reference_id = 0;
+  UTI_ZeroNtp64(&res->reference_ts);
+  res->originate_ts = interleaved ? req->receive_ts : req->transmit_ts;
+
+  advance_time(TST_GetRandomDouble(1e-4, 1e-2));
+  UTI_TimespecToNtp64(&current_time, &res->receive_ts, NULL);
+  advance_time(TST_GetRandomDouble(-1e-4, 1e-3));
+  UTI_TimespecToNtp64(&current_time, &res->transmit_ts, NULL);
+  advance_time(TST_GetRandomDouble(1e-4, 1e-2));
+
+  if (!valid_ts) {
+    switch (random() % (allow_update ? 4 : 5)) {
+      case 0:
+        res->originate_ts.hi = random();
+        break;
+      case 1:
+        res->originate_ts.lo = random();
+        break;
+      case 2:
+        UTI_ZeroNtp64(&res->originate_ts);
+        break;
+      case 3:
+        UTI_ZeroNtp64(&res->receive_ts);
+        break;
+      case 4:
+        UTI_ZeroNtp64(&res->transmit_ts);
+        break;
+      default:
+        assert(0);
+    }
+  }
+
+  if (authenticated) {
+    res->auth_keyid = req->auth_keyid;
+    KEY_GenerateAuth(ntohl(res->auth_keyid), (unsigned char *)res, NTP_NORMAL_PACKET_LENGTH,
+                     res->auth_data, 16);
+    res_length = NTP_NORMAL_PACKET_LENGTH + 4 + 16;
+  } else {
+    res_length = NTP_NORMAL_PACKET_LENGTH;
+  }
+
+  if (!valid_auth) {
+    switch (random() % 3) {
+      case 0:
+        res->auth_keyid++;
+        break;
+      case 1:
+        res->auth_data[random() % 16]++;
+        break;
+      case 2:
+        res_length = NTP_NORMAL_PACKET_LENGTH;
+        break;
+      default:
+        assert(0);
+    }
+  }
+}
+
+static void
+process_response(int valid, int updated)
+{
+  NTP_Local_Address local_addr;
+  NTP_Local_Timestamp local_ts;
+  NTP_Packet *res;
+  uint32_t prev_rx_count, prev_valid_count;
+  struct timespec prev_rx_ts;
+  int prev_open_socket;
+
+  res = &res_buffer.ntp_pkt;
+
+  local_addr.ip_addr.family = IPADDR_UNSPEC;
+  local_addr.sock_fd = NTP_LVM_TO_MODE(res->lvm) == MODE_ACTIVE ? 100 : 101;
+  local_ts.ts = current_time;
+  local_ts.err = 0.0;
+  local_ts.source = NTP_TS_DAEMON;
+
+  prev_rx_count = inst->report.total_rx_count;
+  prev_valid_count = inst->report.total_valid_count;
+  prev_rx_ts = inst->local_rx.ts;
+  prev_open_socket = inst->local_addr.sock_fd != INVALID_SOCK_FD;
+
+  NCR_ProcessRxKnown(inst, &local_addr, &local_ts, res, res_length);
+
+  if (prev_open_socket)
+    TEST_CHECK(prev_rx_count + 1 == inst->report.total_rx_count);
+  else
+    TEST_CHECK(prev_rx_count == inst->report.total_rx_count);
+
+  if (valid)
+    TEST_CHECK(prev_valid_count + 1 == inst->report.total_valid_count);
+  else
+    TEST_CHECK(prev_valid_count == inst->report.total_valid_count);
+
+  if (updated)
+    TEST_CHECK(UTI_CompareTimespecs(&inst->local_rx.ts, &prev_rx_ts));
+  else
+    TEST_CHECK(!UTI_CompareTimespecs(&inst->local_rx.ts, &prev_rx_ts));
+}
+
+void
+test_unit(void)
+{
+  char source_line[] = "127.0.0.1";
+  char conf[][100] = {
+    "port 0",
+    "keyfile ntp_core.keys"
+  };
+  int i, j, interleaved, authenticated, valid, updated, has_updated;
+  CPS_NTP_Source source;
+  NTP_Remote_Address remote_addr;
+
+  CNF_Initialise(0);
+  for (i = 0; i < sizeof conf / sizeof conf[0]; i++)
+    CNF_ParseLine(NULL, i + 1, conf[i]);
+
+  LCL_Initialise();
+  TST_RegisterDummyDrivers();
+  SCH_Initialise();
+  SRC_Initialise();
+  NIO_Initialise(IPADDR_UNSPEC);
+  NCR_Initialise();
+  REF_Initialise();
+  KEY_Initialise();
+
+  for (i = 0; i < 1000; i++) {
+    CPS_ParseNTPSourceAdd(source_line, &source);
+    if (random() % 2)
+      source.params.interleaved = 1;
+    if (random() % 2)
+      source.params.authkey = 1;
+
+    UTI_ZeroTimespec(&current_time);
+    advance_time(TST_GetRandomDouble(1.0, 1e9));
+
+    TST_GetRandomAddress(&remote_addr.ip_addr, IPADDR_UNSPEC, -1);
+    remote_addr.port = 123;
+
+    inst = NCR_GetInstance(&remote_addr, random() % 2 ? NTP_SERVER : NTP_PEER, &source.params);
+    NCR_StartInstance(inst);
+    has_updated = 0;
+
+    for (j = 0; j < 50; j++) {
+      DEBUG_LOG(0, "iteration %d, %d", i, j);
+
+      interleaved = random() % 2;
+      authenticated = random() % 2;
+      valid = (!interleaved || (source.params.interleaved && has_updated)) &&
+              (!source.params.authkey || authenticated);
+      updated = (valid || inst->mode == MODE_ACTIVE) &&
+                (!source.params.authkey || authenticated);
+      has_updated = has_updated || updated;
+
+      send_request();
+
+      send_response(interleaved, authenticated, 1, 0, 1);
+      process_response(0, inst->mode == MODE_CLIENT ? 0 : updated);
+
+      if (source.params.authkey) {
+        send_response(interleaved, authenticated, 1, 1, 0);
+        process_response(0, 0);
+      }
+
+      send_response(interleaved, authenticated, 1, 1, 1);
+      process_response(valid, updated);
+      process_response(0, 0);
+
+      advance_time(-1.0);
+
+      send_response(interleaved, authenticated, 1, 1, 1);
+      process_response(0, 0);
+
+      advance_time(1.0);
+
+      send_response(interleaved, authenticated, 1, 1, 1);
+      process_response(0, inst->mode == MODE_CLIENT ? 0 : updated);
+    }
+
+    NCR_DestroyInstance(inst);
+  }
+
+  KEY_Finalise();
+  REF_Finalise();
+  NCR_Finalise();
+  NIO_Finalise();
+  SRC_Finalise();
+  SCH_Finalise();
+  LCL_Finalise();
+  CNF_Finalise();
+}

test/unit/ntp_core.keys

@@ -0,0 +1,2 @@
+1 MD5 HEX:38979C567358C0896F4D9D459A3C8B8478654579
+2 MD5 HEX:38979C567358C0896F4D9D459A3C8B8478654579

test/unit/util.c

@@ -74,6 +74,14 @@ void test_unit(void) {
   TEST_CHECK(!UTI_IsZeroTimespec(&ts));
   TEST_CHECK(!UTI_IsZeroNtp64(&ntp_ts));
 
+  ntp_ts.hi = 0;
+  ntp_ts.lo = 0;
+
+  UTI_Ntp64ToTimespec(&ntp_ts, &ts);
+  TEST_CHECK(UTI_IsZeroTimespec(&ts));
+  UTI_TimespecToNtp64(&ts, &ntp_ts, NULL);
+  TEST_CHECK(UTI_IsZeroNtp64(&ntp_ts));
+
   ntp_fuzz.hi = htonl(1);
   ntp_fuzz.lo = htonl(3);
   ntp_ts.hi = htonl(1);

util.c

@@ -754,8 +754,11 @@ UTI_Ntp64ToTimespec(NTP_int64 *src, struct timespec *dest)
 {
   uint32_t ntp_sec, ntp_frac;
 
-  /* As yet, there is no need to check for zero - all processing that
-     has to detect that case is in the NTP layer */
+  /* Zero is a special value */
+  if (UTI_IsZeroNtp64(src)) {
+    UTI_ZeroTimespec(dest);
+    return;
+  }
 
   ntp_sec = ntohl(src->hi);
   ntp_frac = ntohl(src->lo);