Use empty string instead of "." (which is normally the root directory)
as the default value of dumpdir and logdir to indicate they are not
specified. Print warnings in syslog when trying to log or dump
measurements without dumpdir or logdir.
Add support for authenticating MS-SNTP responses in Samba (ntp_signd).
Supported is currently only the old MS-SNTP authenticator field. It's
disabled by default. It can be enabled with the --enable-ntp-signd
configure option and the ntpsigndsocket directive, which specifies the
location of the Samba ntp_signd socket.
Since the update to NTPv4, when the clock is in the synchronised state
and the clock updates stop (e.g. sources become unreachable), it doesn't
switch to the unsynchronised state and the local reference is never
activate. This can be a problem for clients that rely on the server to
always have root distance below some value (e.g. chronyd's maxdistance).
Add a timer that will activate the local reference when the root
distance reaches a specified threshold. It can be configured with the
distance option in the local directive (by default 1.0 second).
Allow the local directive to be specified without the stratum field.
It's an option now, with default value 10. Also, move the parsing code
to cmdparse.c to make it available to the client.
Add maxdrift directive to set the maximum assumed drift of the clock,
which sets the maximum frequency offset chronyd is allowed to use to
to correct the drift.
Require that at least one of the sources specified with this option is
selectable (i.e. recently reachable and not a falseticker) before
updating the clock. Together with the trust option this may be useful to
allow a trusted, but not very precise, reference clock or a trusted
authenticated NTP source to be safely combined with unauthenticated NTP
sources in order to improve the accuracy of the clock. They can be
selected and used for synchronization only if they agree with the
trusted and required source.
Assume time from a source that is specified with the trust option is
always true. It can't be rejected as falseticker in the source
selection if sources that are specified without this option don't agree
with it.
When the measured NTP or command request rate of a client exceeds
a threshold, reply only to a small fraction of the requests to reduce
the network traffic. Clients are allowed to send a burst of requests.
Try to detect broken clients which increase the request rate when not
getting replies and suppress the rate limiting for them.
Add ratelimit and cmdratelimit directives to configure the thresholds,
bursts and leak rates independently for NTP and command response rate
limiting. Both are disabled by default. Commands from localhost are
never limited.
Add maxdistance directive to set the maximum root distance the sources
are allowed to have to be selected. This is useful to reject NTPv4
sources that are no longer synchronized and report large dispersion.
The default value is 3 seconds.
Try to create the directory where will be the Unix domain command socket
bound to allow starting with empty /var/run. Check the permissions and
owner/group in case the directory already existed. It MUST NOT be
accessible by others as permissions on Unix domain sockets are ignored
on some systems (e.g. Solaris).
Create logdir and dumpdir before dropping root. Set their uid/gid to the
user chronyd will switch to. This allows chronyd to create the
directories in a directory where the user won't have write permissions
(e.g. /var/lib).
In addition to the IPv4/IPv6 command sockets, create also a Unix domain
socket to process cmdmon requests. For now, there is no difference for
authorized commands, packets from all sockets need to be authenticated.
The default path of the socket is /var/run/chrony/chronyd.sock. It can
be configured with the bindcmdaddress directive with an address starting
with /.
The leaponly option can be used to enable a mode where only leap seconds
are smoothed out and normal offset/frequency changes are ignored. This
is useful to make the interval in which a leap second is smoothed out
constant and allow an NTP client to use multiple leap smearing servers
safely.
Time smoothing determines an offset that needs to be applied to the
cooked time to make it smooth for external observers. Observed offset
and frequency change slowly and there are no discontinuities. This can
be used on an NTP server to make it easier for the clients to track the
time and keep their clocks close together even when large offset or
frequency corrections are applied to the server's clock (e.g. after
being offline for longer time).
Accumulated offset and frequency are smoothed out in three stages. In
the first stage, the frequency is changed at a constant rate (wander) up
to a maximum, in the second stage the frequency stays at the maximum for
as long as needed and in the third stage the frequency is brought back
to zero.
Time smoothing is configured by the smoothtime directive. It takes two
arguments, maximum frequency offset and maximum wander. It's disabled by
default.
In addition to the system driver handling add new modes to slew or step
the system clock for leap second, or ignore it completely. This can be
configured with leapsecmode directive.
The minsamples and maxsamples directives now set the default value,
which can be overriden for individual sources in the server/peer/pool
and refclock directives.
A new option can be now used in the pool directive: maxsources sets the
maximum number of sources that can be used from the pool, the default
value is 4.
On start, when the pool name is resolved, chronyd will add up to 16
sources, one for each resolved address. When the number of sources from
which at least one valid reply was received reaches maxsources, the
other sources will be removed.
In addition to the quadratic function, allow configuration of the
compensation with a file containing list of (temperature, compensation)
points used for linear interpolation and extrapolation.
The pool directive can be used to configure chronyd for a pool of NTP
servers (e.g. pool.ntp.org). The name is expected to resolve to multiple
addresses which change over time.
On start, a source will be added for each resolved address. When a
source from the pool is unreachable or marked as falseticker, chronyd
will try to replace the source with a newly resolved address of the
pool.
The minimum interval between replacements is currently set to 244
seconds to avoid frequent DNS requests.
This should reduce the number of possible memory leaks reported by
valgrind. The remaining reported leaks are sched tqe allocation, async
DNS instance allocation, cmdmon response/timestamp cell allocation, and
clientlog subnet allocation.
