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 14:38:09 -0800 Message-ID: <1328395089-15932-1-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 imr3.ericy.com ([198.24.6.13]:52931 "EHLO imr3.ericy.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751408Ab2BDWiR (ORCPT ); Sat, 4 Feb 2012 17:38:17 -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. 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 --- V4: change log. Thanks for Eric Dumazet to take care of "sk is not NULL" case. He also provide code for this fix. 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