Hello, Since I see the subject is ethernet padding I would like to mention what we use together with PTP:
A timestamping card which adds 9 bytes of VSS-monitoring trailer to the ethernet packet. Depending on the exact value of the timestamp, wireshark can misdetect it and show a "wrong" FCS plus 5 bytes padding, see https://github.com/boundary/wireshark/blob/master/epan/dissectors/packet-vssmonitoring.c#L139 I'm attaching a small capture where you can see traffic from 2 NICs, one which adds a trailer to all incoming packets and one which does not. I am anonymizing the MAC vendor for the timestamping card. On 31/01/2019 19:24, Jiri Benc wrote: > On Thu, 31 Jan 2019 16:28:30 +0000, Vincent Li X wrote: >> we might also need to check again m->header.messageLength is bigger than >> cnt. > > This might not be a bad idea; if the packet length is inconsistent with > the PTP or 802.3 standard, a warning can be emitted and the packet > dropped and not processed further. This would make linuxptp more robust > against randomly malformed packets and would give some indication to > users that the other end or intermediate network equipment is broken. > > Jiri
ptp2.pcap
Description: application/vnd.tcpdump.pcap
_______________________________________________ Linuxptp-devel mailing list Linuxptp-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linuxptp-devel
