From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shawn Lu Subject: [PATCH] tcp_v4_send_reset: binding oif to iif in no sock case Date: Sat, 4 Feb 2012 13:44:57 -0800 Message-ID: <1328391897-15241-1-git-send-email-shawn.lu@ericsson.com> References: Mime-Version: 1.0 Content-Type: text/plain Cc: eric.dumazet@gmail.com, netdev@vger.kernel.org, xiaoclu@gmail.com To: davem@davemloft.net Return-path: Received: from imr4.ericy.com ([198.24.6.9]:40260 "EHLO imr4.ericy.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751944Ab2BDVpP (ORCPT ); Sat, 4 Feb 2012 16:45:15 -0500 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: Binding RST packet outgoing interface to incoming interface for tcp v4 when there is no socket associate with it. 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 --- V3: reformat comments as suggested net/ipv4/tcp_ipv4.c | 5 +++++ 1 files changed, 5 insertions(+), 0 deletions(-) diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 90e4793..4d6f81c 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -676,6 +676,11 @@ 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; -- 1.7.0.4