This driver is intended to complete system-specific drivers that don't
have implemented all required driver functionality. Currently, it
implements offset functions working on top of system-specific frequency
functions. Offsets are corrected by changing frequency, similarly to
fast slewing implemented in the Linux driver.
This is to make sure chronyd will see the remote address as 127.0.0.1
and allow access even when localhost resolves to an address of a
non-loopback interface.
Run getaddrinfo()/gethostbyname() in separate thread to avoid blocking.
Only one resolving thread is running at one time, so this should work
also on systems where the functions are not thread-safe.
Use the new asynchronous call to resolve addresses of NTP servers
configured by the server/peer directives. Introduce a callback to be
notified when the first resolving attempt ends to correctly finish
chronyd initialization (dumpfile reload and reference mode end).
This will be needed to prevent loading of dump files after sources have
already accumulated samples and possibly reference was already updated
when async resolving of sources is implemented.
When source is set as active, it's receiving reachability updates (e.g.
offline NTP sources are not active).
Also add function to count active sources.
Instead of giving up when a source has 7 reach updates, continue as long
as at least one source has fewer than 7 updates and can still have 3
samples to be selectable in that number of updates.
When no sources are responding, it will give up sooner.
With special reference update modes, the timeout handlers may add or
remove file descriptors from the read fd set, so it needs to be copied
for select() call after they are dispatched. Also, they can now request
quit, so the exit flag needs to be checked before select() to avoid
hanging.
If there are extra arguments on the chronyd command line, they will be
parsed as lines in a configuration file and the normal configuration file
will be ignored.
Explicitly set the number of iburst samples to the size of the register
to make sure there are at least 7 reachability updates and the
initstepslew mode can be ended.
The initstepslew code has its own minimal NTP implementation. Drop the
code, add a new initstepslew mode to the reference updating code and
use regular NTP sources with iburst flag for initstepslew addresses
instead. When an update is made or a source is found unreachable, log a
message, remove the initstepslew sources and switch to normal mode.
This reduces code duplication and makes initstepslew use features
implemented only in the main code like source combining or SO_TIMESTAMP
support.
