kern/158307: ipv6_pktinfo breaks IPV6_USE_MIN_MTU
marka at isc.org
Sun Jun 26 09:40:11 UTC 2011
>Synopsis: ipv6_pktinfo breaks IPV6_USE_MIN_MTU
>Arrival-Date: Sun Jun 26 09:40:01 UTC 2011
>Originator: Mark Andrews
>Release: FreeBSD 8.2-STABLE i386
System: FreeBSD sex.dv.isc.org 8.2-STABLE FreeBSD 8.2-STABLE #10: Sat Feb 26 18:02:12 EST 2011 marka at sex.dv.isc.org:/usr/obj/usr/src/sys/DEBUG i386
If IPV6_PKTINFO is set as a control with sendmsg() then
IPV6_USE_MIN_MTU state set by setsockopt() is ignored.
Run named and look at any IPv6 UDP response > 1280 bytes.
These are all supposed to be fragmented at 1280 as named
sets IPV6_USE_MIN_MTU to 1 on all IPv6 UDP sockets.
PMTUD really doesn't work well for DNS which is one of the
reasons why IPV6_USE_MIN_MTU was defined in the first place.
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