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.
Update the reachability register of a refclock source by 1 if a valid
measurement is received by the drivers between source polls, and not
only when it is accumulated to sourcestats, similarly to how
reachability works with NTP sources.
This avoids drops in the reported reachability when a PHC refclock is
dropping samples due to significant changes in the measured delay (e.g.
due to high PCIe load), or a PPS refclock dropping samples due to failed
lock.
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 libsystemd is available, and it's not disabled via --without-libsystemd,
link to it and call sd_notify() before and after the main loop.
This allows systemd to track the exact moment when all the setup is completed
and the unit is considered activated (with Type=notify), in a race-free manner.
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.
DNSSEC requires the system time to be synced in order to work,
as the signature date and expiration need to be checked by
resolvers. But it is possible that syncing the times requires
doing DNS queries. Add a paragraph to the FAQ explaining how
to break this cycle by asking nss-resolved to always avoid
DNSSEC when chronyd tries to resolve hostnames.
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.
In the source selection, check for the unsynchronized leap status after
getting sourcestats data. The unsynchronized source status is supposed
to indicate an unsynchronized source that is providing samples, not a
source which doesn't have any samples.
Also, fix the comment describing the status.
Fixes: 4c29f8888c ("sources: handle unsynchronized sources in selection")
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.
Before opening new IPv4/IPv6 server sockets, chronyd will check for
matching reusable sockets passed from the service manager (for example,
passed via systemd socket activation:
https://www.freedesktop.org/software/systemd/man/latest/sd_listen_fds.html)
and use those instead.
Aside from IPV6_V6ONLY (which cannot be set on already-bound sockets),
the daemon sets the same socket options on reusable sockets as it would
on sockets it opens itself.
Unit tests test the correct parsing of the LISTEN_FDS environment
variable.
Add 011-systemd system test to test socket activation for DGRAM and
STREAM sockets (both IPv4 and IPv6). The tests use the
systemd-socket-activate test tool, which has some limitations requiring
workarounds discussed in inline comments.
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>
When the refresh command is issued, instead of trying to replace all
NTP sources as if they were unreachable or falsetickers, keep using the
current address if it is still returned by the resolver for the name.
This avoids unnecessary loss of measurements and switching to
potentially unreachable addresses.
