Commit e2446eaa authored Feb 04, 2012 by Shawn Lu Committed by David S. Miller Feb 04, 2012

tcp_v4_send_reset: binding oif to iif in no sock case



Binding RST packet outgoing interface to incoming interface
for tcp v4 when there is no socket associate with it.
when sk is not NULL, using sk->sk_bound_dev_if instead.
(suggested by Eric Dumazet).

This has few benefits:
1. tcp_v6_send_reset already did that.
2. This helps tcp connect with SO_BINDTODEVICE set. When
connection is lost, we still able to sending out RST using
same interface.
3. we are sending reply, it is most likely to be succeed
if iif is used

Signed-off-by: Shawn Lu <shawn.lu@ericsson.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 5962b35c

net/ipv4/tcp_ipv4.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -651,6 +651,11 @@ static void tcp_v4_send_reset(struct sock sk, struct sk_buff skb)
		arg.iov[0].iov_len, IPPROTO_TCP, 0);
		arg.csumoffset = offsetof(struct tcphdr, check) / 2;
		arg.flags = (sk && inet_sk(sk)->transparent) ? IP_REPLY_ARG_NOSRCCHECK : 0;
		/* When socket is gone, all binding information is lost.
		* routing might fail in this case. using iif for oif to
		* make sure we can deliver it
		*/
		arg.bound_dev_if = sk ? sk->sk_bound_dev_if : inet_iif(skb);

		net = dev_net(skb_dst(skb)->dev);
		arg.tos = ip_hdr(skb)->tos;

Admin message