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>
This commit is contained in:
Jiri Benc
2012-02-09 09:35:49 +00:00
committed by David S. Miller
parent 7a3198a897
commit 4c507d2897
8 changed files with 17 additions and 1 deletions

View File

@@ -1289,6 +1289,10 @@ static int do_ip_getsockopt(struct sock *sk, int level, int optname,
int hlim = inet->mc_ttl;
put_cmsg(&msg, SOL_IP, IP_TTL, sizeof(hlim), &hlim);
}
if (inet->cmsg_flags & IP_CMSG_TOS) {
int tos = inet->rcv_tos;
put_cmsg(&msg, SOL_IP, IP_TOS, sizeof(tos), &tos);
}
len -= msg.msg_controllen;
return put_user(len, optlen);
}