This commit allows the user to select a PHC refclock associated with
an Ethernet interface by specifying the interface name. This allows
the user to handle situations where multiple NICs are exposing PHC
devices (or non-NIC PHC device files exist in the system) in a more
streamline manner.
However at the start means "in whatever way"/"to whatever extent".
("However chrony is configured, it won't let you in without allow")
However incorrectly at the start usually means "But" was intended.
Add "waitunsynced" option to specify how long chronyd needs to wait
before it can activate the local reference when the clock is not
synchronized to give the configured sources a chance to synchronize the
local clock after start. The default is 300 seconds when the orphan
option is enabled (same as the ntpd's default orphanwait), 0 otherwise.
Add "waitsynced" option to specify how long it should wait when the
clock is synchronized. It is an additional requirement to the distance
and activate options.
Replace the hardcoded list of open commands (accessible over UDP),
with a list that can be configured with a new "opencommands" directive.
The default matches the original list. All read-only commands except
accheck and cmdaccheck can be enabled. The naming follows the chronyc
naming. Enable the N_SOURCES request only when needed.
This makes it possible to have a full monitoring access without access
to the Unix domain socket. It also allows restricting the monitoring
access to a smaller number of commands if some commands from the default
list are not needed.
Mention in the man page that the protocol of the non-default commands is
not consider stable and the information they provide may have security
implications.
This refclock uses an RTC as reference source. If the RTC doesn't
support reporting an update event this source is quite coarse as it
usually needs a slow bus access to be read and has a precision of only
one second. If reporting an update event is available, the time is read
just after such an event which improves precision.
Depending on hardware capabilities you might want to combine it with a
PPS reference clock sourced from the same chip.
Note that you can enable UIE emulation in the Linux kernel to make a RTC
without interrupt support look like one with irqs in return for some
system and bus overhead.
Co-authored-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Reduce the minimum number of samples required by the filter from
min(4, length) to 1.
This makes the filtering less confusing. The sample lifetime is limited
to one poll and the default filtering of the SOCK refclock (where the
maximum number of samples per poll is unknown) is identical to the other
refclocks.
A concern with potential variability in number of samples per poll below
4 is switching between different calculations of dispersion in
combine_selected_samples() in samplefilt.c.
The 106-refclock test shows how the order of refclocks in the config can
impact the first filtered sample and selection. If the PPS refclock
follows SHM, a single low-quality PPS sample is accepted in the same
poll where SHM is selected and the initial clock correction started,
which causes larger skew later and delays the first selection of the PPS
refclock.
Add ntsaeads directive to specify a list of AEAD algorithms enabled for
NTS. The list is shared between the server and client. For the client it
also specifies the order of priority. The default is "30 15", matching
the previously hardcoded preference of AES-128-GCM-SIV (30) over
AES-SIV-CMAC-256 (15).
If the pid file path is specified as '/', skip handling it,
as it is not only unnecessary but complicates managing the
service. A systemd unit can manage the program without any
need for this functionality, and it makes process tracking
simpler and more robust.
The implementation matches the bindcmdaddress directive.
Add ptpdomain directive to set the domain number of transmitted and
accepted NTP-over-PTP messages. It might need to be changed in networks
using a PTP profile with the same domain number. The default domain
number of 123 follows the current NTP-over-PTP specification.
When an NTP source is specified with the offset option, the corrected
offset may get outside of the supported NTP interval (by default -50..86
years around the build date). If the source passed the source selection,
the offset would be rejected only later in the adjustment of the local
clock.
Check the offset validity as part of the NTP test A to make the source
unselectable and make it visible in the measurements log and ntpdata
report.
This option sets an activating root distance for the local reference. The
local reference will not be used until the root distance drops below the
configured value for the first time. This can be used to prevent the local
reference from being activated on a server which has never been synchronised
with an upstream server. The default value of 0.0 causes no activating
distance to be used, such that the local reference is always eligible for
activation.
Add "kod" option to the ratelimit directive to respond with the KoD
RATE code to randomly selected requests exceeding the configured limit.
This complements the client support of KoD RATE. It's disabled by
default.
There can be only one KoD code in one response. If both NTS NAK and RATE
codes are triggered, drop the response. The KoD RATE code can be set in
an NTS-authenticated response.
The existing implementation of getting leap second information from a
timezone in get_tz_leap() relies on non-portable C library behaviour.
Specifically, mktime is not required to return '60' in the tm_sec field
when a leap second is inserted leading to "Timezone right/UTC failed
leap second check, ignoring" errors on musl based systems.
This patch adds support for getting leap second information from the
leap-seconds.list file included with tzdata and adds a new configuration
directive leapseclist to switch on the feature.
Accept "ipv4" and "ipv6" options in the server/pool/peer directive to
use only IPv4 or IPv6 addresses respectively.
The configuration is different from the "server [-4|-6] hostname" syntax
supported by ntpd to avoid breaking existing scripts which expect the
hostname to always be the first argument of the directives.
If the network correction is known for both the request and response,
and their sum is not larger that the measured peer delay, allowing the
transparent clocks to be running up to 100 ppm faster than the client's
clock, apply the corrections to the NTP offset and peer delay. Don't
correct the root delay to not change the estimated maximum error.
Refresh NTP sources specified by hostname periodically (every 2 weeks
by default) to avoid long-running instances using a server which is no
longer intended for service, even if it is still responding correctly
and would not be replaced as unreachable, and help redistributing load
in large pools like pool.ntp.org. Only one source is refreshed at a time
to not interrupt clock updates if there are multiple selectable servers.
The refresh directive configures the interval. A value of 0 disables
the periodic refreshment.
Suggested-by: Ask Bjørn Hansen <ask@develooper.com>
Rework handling of late HW TX timestamps. Instead of suspending reading
from client-only sockets that have HW TX timestamping enabled, save the
whole response if it is valid and a HW TX timestamp was received for the
source before. When the timestamp is received, or the configurable
timeout is reached, process the saved response again, but skip the
authentication test as the NTS code allows only one response per
request. Only one valid response per source can be saved. If a second
valid response is received while waiting for the timestamp, process both
responses immediately in the order they were received.
The main advantage of this approach is that it works on all sockets, i.e.
even in the symmetric mode and with NTP-over-PTP, and the kernel does
not need to buffer invalid responses.
Specify maxpoll for HW timestamping (default minpoll + 1) to track the
PHC well even when there is little NTP traffic on the interface. After
each PHC reading schedule a timeout according to the maxpoll. Polling
between minpoll and maxpoll is still triggered by HW timestamps.
Wait for the first HW timestamp before adding the timeout to avoid
polling PHCs on interfaces that are enabled in the configuration but
not used for NTP. Add a new scheduling class to separate polling of
different PHCs to avoid too long intervals between processing I/O
events.
In some cases even the new timeout of 1 millisecond is not sufficient to
get all HW TX timestamps. Add a new directive to allow users to
specify longer timeouts.
