Fixed bug where negative offsets were not properly handled because
clock_timespec_subtract clamps values to zero.
Implement support for SO_TIMESTAMP to get accurate packet
reception timestamp.
Implemented delay requests for measuring packet transfer delay.
Implemented clock drift estimation to bring the clocks closer to
sync and to filter out measurement jitter.
If multicast PTP packets are not being received, rejoin the multicast group.
This automatically recovers from situations such as rebooting a network switch.
What works:
- Basic server & client operation
- Transmission and reception of announce, sync and follow-up
Still missing:
- SO_TIMINGS for getting more precise packet timestamps
- Implementation of delay_req and delay_resp packets
- Status and stop interfaces for the daemon
