Move the res_init() call from do_name_to_ipaddress() into a separate
privops operation. Use it in ntp_sources and avoid unnecessary
res_init() calls in the main thread.
Coverity doesn't seem to like the new field in the IPAddr struct (used
as explicit padding of the structure) to be left uninitialized, even
though it's never used for anything and is cleared by memset() in
UTI_IPHostToNetwork() before leaving the process.
While the measurements log can be useful for debugging problems in NTP
configuration (e.g. authentication failures with symmetric keys), it
seems most users are interested only in valid measurements (e.g. for
producing graphs) and don't expect/handle entries where some of the RFC
5905 tests 1-7 failed. Modify the measurements log option to log only
valid measurements, and for debugging purposes add a new rawmeasurements
option.
When the server's transmit timestamp was updated with a kernel/HW
timestamp, it didn't include the time smoothing offset. If the offset
was larger than one second, the update failed and clients using the
interleaved mode received less accurate timestamps. If the update
succeeded, the clients received timestamps that were not adjusted for
the time smoothing offset, which added an error of up to 0.5s/1s to
their measured offset/delay.
Fix the update to include the smoothing offset in the new timestamp.
Handle zero NTP timestamp in UTI_Ntp64ToTimespec() as a special value to
make it symmetric with UTI_TimespecToNtp64(). This is needed since
commit d75f6830f1, in which a timestamp is
converted back and forth without checking for zero.
It also makes zero NTP timestamps more apparent in debug output.
When accumulating a new sample, check if the new RTC time is newer the
last sample time. If it is not, discard all previous samples, assuming
something has stepped the RTC, or it's a broken RTC/driver.
This reduces leak of sample times (and receive timestamps which are
related to sample times), which could be useful in off-path attacks on
unauthenticated symmetric interleaved mode.
