commit 4c507d2897bd9be810b3403ade73b04cf6fdfd4a
author Jiri Benc <jbenc@redhat.com> Thu Feb 09 09:35:49 2012 +0000
committer David S. Miller <davem@davemloft.net> Mon Feb 13 00:46:41 2012 -0500
tree dfd808407a0f800195e994bb2cfc401fae23295e
parent 7a3198a89722ad9521d22b05938d357eac7460fa

net: implement IP_RECVTOS for IP_PKTOPTIONS

Currently, it is not easily possible to get TOS/DSCP value of packets from
an incoming TCP stream. The mechanism is there, IP_PKTOPTIONS getsockopt
with IP_RECVTOS set, the same way as incoming TTL can be queried. This is
not actually implemented for TOS, though.

This patch adds this functionality, both for IPv4 (IP_PKTOPTIONS) and IPv6
(IPV6_2292PKTOPTIONS). For IPv4, like in the IP_RECVTTL case, the value of
the TOS field is stored from the other party's ACK.

This is needed for proxies which require DSCP transparency. One such example
is at http://zph.bratcheda.org/.

Signed-off-by: Jiri Benc <jbenc@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>