Add maxunreach option to NTP sources and refclocks to specify the
maximum number of polls that the source can stay selected for
synchronization when it is unreachable (i.e. no valid sample was
received in the last 8 polls).
It is an additional requirement to having at least one sample more
recent than the oldest sample of reachable sources.
The default value is 100000. Setting the option to 0 disables selection
of unreachable sources, which matches RFC 5905.
To minimize the impact of potential attacks targeting chronyc started
under root (e.g. performed by a local chronyd process running without
root privileges, a remote chronyd process, or a MITM attacker on the
network), add support for changing the effective UID/GID in chronyc
after start.
The user can be specified by the -u option, similarly to chronyd. The
default chronyc user can be changed by the --with-chronyc-user
configure option. The default value of the default chronyc user is
"root", i.e. chronyc doesn't try to change the identity by default.
The default chronyc user does not follow the default chronyd user
set by the configure --with-user option to avoid errors on systems where
chronyc is not allowed to change its UID/GID (e.g. by a SELinux policy).
When the cyclelogs command is issued, check if the file specified by the
-l option is still in its place and if not try opening it again. If that
fails (e.g. due to chrony no longer having root privileges), keep the
old file handle to avoid losing log messages.
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.
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.
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")
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.
Update the serverstats response to use the new 64-bit integers.
Don't define a new value for the response as it already had an
incompatible change since the latest release (new fields added for
timestamp counters).
In a non-tty session with chronyc it is not possible to detect the
end of the response without relying on timeouts, or separate responses
to a repeated command if using the -c option.
Add -e option to end each response with a line containing a single dot.
If AES-128-GCM-SIV is available on the client, add it to the requested
algorithms in NTS-KE as the first (preferred) entry.
If supported on the server, it will make the cookies shorter, which
will get the length of NTP messages containing only one cookie below
200 octets. This should make NTS more reliable in networks where longer
NTP packets are filtered as a mitigation against amplification attacks
exploiting the ntpd mode 6/7 protocol.
Add a new test for maximum delay using a long-term estimate of a
p-quantile of the peer delay. If enabled, it replaces the
maxdelaydevratio test. It's main advantage is that it is not sensitive
to outliers corrupting the minimum delay.
As it can take a large number of samples for the estimate to reach the
expected value and adapt to a new value after a network change, the
option is recommended only for local networks with very short polling
intervals.
Allow sources to accumulate samples with the leap status set to not
synchronized. Define a new state for them to be ignored in the
selection. This is intended for sources that are never synchronized and
will be used only for stabilization.
Report the number of received interleaved requests and current timestamp
count with their span.
Expand the serverstats description in chronyc man page.
For sources specified by an IP address, keep the original address as the
source's name and pass it to the NCR instance. Allow the sources to go
through the replacement process if their address has changed.
This will be useful with NTS-KE negotiation.
The IP-based source names are now provided via cmdmon. This means
chronyc -n and -N can show two different addresses for a source.
Add a new field to the CLIENT_ACCESSES_BY_INDEX request to specify the
minimum number of NTP or cmdmon packets for a client to be reported.
Add -p option to the chronyc clients command to specify the threshold
(by default 0). This option can be used to minimize the number of cmdmon
requests when interested only in clients sending a large number
of requests.
Add a flag to the CLIENT_ACCESSES_BY_INDEX request to reset the
NTP/cmdmon hits/dropped counters after reporting the current values.
Add -r option to the chronyc clients command to perform the reset. This
should make it easier to find clients that send large number of requests
over short periods of time.
