From 6843bf164d1de749e2998cfc5c2291dc86523e77 Mon Sep 17 00:00:00 2001 From: Shawn Lu Date: Sat, 4 Feb 2012 12:38:09 +0000 Subject: [PATCH 27/72] tcp_v4_send_reset: binding oif to iif in no sock case [ Upstream commit e2446eaab5585555a38ea0df4e01ff313dbb4ac9 ] 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 Acked-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv4/tcp_ipv4.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index c89e354..eb90aa8 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -650,6 +650,11 @@ 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; -- 1.7.9.4