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Request for Geneve DLT type


From: Jesse Gross <jesse () nicira com>
Date: Tue, 27 Jan 2015 16:46:31 -0800

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.
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