IPv6: Ignore PTB packets with an MTU < 1280HEADmain

RFC 2460 section 5 paragraph 7 allowed a Packet Too Big message
to report a Next-Hop MTU less than 1280 in support of 6-to-4 routers.
A node receiving such a message was required to add a Fragment
Header to outgoing packets, even though they were not fragmented.

Almost 20 years later, RFC 8200 was published.  It obsoletes RFC 2460
and removes that paragraph.  UNH IOL Intact was updated to test for
compliance with the new standard.

Remove code supporting that obsolete paragraph.

Test cases v6LC_4_1_06a and 06b failed before this change, saying:

    DUT processed PTB and sent a fragmented echo reply

Those two test cases now pass:

    DUT did not process PTB and sent un-fragmented echo reply

All PMTU test cases pass except v6LC_4_1_08.  It fails because we
ignore the MTU in RAs.

Reviewed by:	tuexen
MFC After:	1 month
Sponsored by:	Dell Inc.
Differential Revision: https://reviews.freebsd.org/D51835

0 files changed, 0 insertions, 0 deletions