On Jan 27, 2015, at 4:46 PM, Jesse Gross <je...@nicira.com> wrote: > I'm working on implementing support for Geneve in libpcap, which is > documented here: > http://tools.ietf.org/html/draft-gross-geneve-02 > > Geneve is a tunneling protocol than can encapsulate many different > things - normally this would be Ethernet, IP, or IPv6 but it can be > anything with an EtherType. I would like for filters that appear after > the Geneve keyword to apply to the inner payload, i.e. geneve && ip. > > Since the inner protocol is no longer the same as the outer wire > format, the checks that are done on linktype don't really make sense > at that point. The easiest solution would seem to be to allocate a new > DLT for Geneve and change to that when processing the inner header, so > I'm requesting a new type for that purpose. I realize that this is a > little weird because it's not actually a format that will ever appear > in pcap files and could also be handled purely internally (similar to > the is_pppoes variable). However, having implemented it both ways, it > definitely seems cleaner to have a new type that fits into the > existing switch statements rather than a bunch on one-off checks.
Having a placeholder DLT_ type that doesn't actually correspond to anything you get from an interface, and a corresponding LINKTYPE_ value that won't ever appear in files, definitely doesn't seem at all clean to me; it's using DLT_/LINKTYPE_ values for a purpose completely different from the purpose for which they are intended. I will see whether the handling of PPPoE and MPLS can be cleaned up internally to gencode.c; if so, *that* would be the right way to handle Geneve. _______________________________________________ tcpdump-workers mailing list tcpdump-workers@lists.tcpdump.org https://lists.sandelman.ca/mailman/listinfo/tcpdump-workers
