David Garijo writes: > Hello, > > I've been thinking of the possibility of adding hardware support for > NTP so that it can timestamp the packets sent and received more > acurately. > > An example of this would be to overwrite the timestamp of the packets > (by hardware) right before sending/receiving them with the actual time > of departure/arrival if a "hardware support" option is enabled (like > some kind of timestamp unit). > > It sounds as if I would need to modify the project heavily, so I > suppose the best and most realistic approach would be to add a new > option to the (Linux) kernel instead of rewriting the ntp programs > offered. > > The code for the NTP daemon (ntpd) is quite complex, so I'm not quite > sure how nor when the packets are sent/received/timestamped. On the > other hand, as far as I've noticed, sntp uses libevent and > recvfrom/sendto to handl e the packets, so I tend to think that maybe > I should start by taking a look at sys/socket.h instead of worrying > about anything ntp related. Any suggestions? Do you know of an ideal > file/function that I should edit?
Changing the timestamps as the packet leaves is not a good general solution, as there can be checksums involved. NTP already has some hardware timestamping support in it. I think the better approach is to track the actual hardware timestamps and use "interleave" mode. Is this a project you are doing "for fun"? H _______________________________________________ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
