As you feel, I don't care on the Ethernet frame. Nor do I think we should try to fix it or criticize it. If the packet pass the Linux kernel and received by the PTP daemon, we should not care.
For me, the only question is, if the Ethernet frame does have padding and the PTP frame is proper. Is there a problem? Is the PTP messaged parsed in a correct manner? Erez ________________________________________ From: Jiri Benc [jb...@redhat.com] Sent: 31 January 2019 17:03 To: Richard Cochran Cc: Mats Bergman H; Richard Jönsson; Linuxptp-devel@lists.sourceforge.net Subject: Re: [Linuxptp-devel] ptp4l wrongly takes padding bytes as TLV? On Thu, 31 Jan 2019 07:41:38 -0800, Richard Cochran wrote: > FWIW, Wireshark shows "Bad FCS" for this frame. Please fix it at the > sender. To be fair, this is just an artifact of Wireshark guessing wrong on the packet structure. AFAIK there's no indication of the frames having FCS or not in pcap. Wireshark has to guess and when it sees the packet being 6 bytes longer than the payload and 64 bytes in total, it's natural to guess it's 2 bytes padding and 4 bytes FCS to satisfy the Ethernet minimum length requirements. While in fact, I expect that the FCS got stripped and the frame was 68 bytes. The real FCS was most likely correct. Seeing the padding bytes not being zero, I cannot resist wondering what part of its memory is the sender leaking. Could the leak be used to gather some interesting data? ;-) In any case, this behavior is wrong on several levels. And with the likely security issue present, I don't think it's worth the time to consider this hardware seriously. Jiri _______________________________________________ Linuxptp-devel mailing list Linuxptp-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linuxptp-devel _______________________________________________ Linuxptp-devel mailing list Linuxptp-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linuxptp-devel
