If the remote stratum is higher than ours, try to lock on the peer's
polling to minimize our response time by slightly extending our delay or
waiting for the peer to catch up with us as the random part in the
actual interval is reduced. If the remote stratum is equal to ours, try
to interleave evenly with the peer.
If the remote peer uses a polling interval shorter than the local
minimum, the local peer will be unable to send any packets as the
timeout will be updated on every received valid packet and will never
expire.
Modify the delay calculation to aim at poll interval away since the last
transmit.
Also, share the delay calculation code with transmit_timeout().
This should prevent chronyd from getting stuck and refusing new samples
due to failing test4 when the current measured frequency offset is close
to 1.0. That can happen when the system clock is stepped forward behind
chronyd's back.
Allow different hash functions to be used in the NTP and cmdmon
protocols. This breaks the cmdmon protocol compatibility. Extended key
file format is used to specify the hash functions for chronyd and new
authhash command is added to chronyc. MD5 is the default and the only
function included in the chrony source code, other functions will be
available from libraries.
Add new flag to source struct to indicate when source is selectable
(packets with good headers are received) and use a reachability
register for last 8 samples instead of the reachable flag. Source
drivers now provide only reachability updates.
Split test7 into two and to accumulate the sample require that all tests
pass, except the one which checks packet stratum is not higher than ours.
Also, don't mark the source as unreachable when only test4c fails.
Require that the ratio of the increase in delay from the minimum one in
the stats data register to the standard deviation of the offsets in the
register is less than maxdelaydevratio or the difference between
measured offset and predicted offset is larger than the increase in
delay. In the allowed delay increase is included also skew and maximum
clock frequency error.
maxdelaydevratio is 10.0 by default.
Instead of following skew changes, adjust polling interval so that the
number of measurements used in the regression algorithm remains close to
a target value. It can be configured with a new polltarget option
(6 by default).
