Patchwork tcp_v4_send_reset: binding oif to iif in no sock case

login
register
mail settings
Submitter Shawn Lu
Date Feb. 4, 2012, 10:38 p.m.
Message ID <1328395089-15932-1-git-send-email-shawn.lu@ericsson.com>
Download mbox | patch
Permalink /patch/139597/
State Accepted
Delegated to: David Miller
Headers show

Comments

Shawn Lu - Feb. 4, 2012, 10:38 p.m.
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>
---
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(-)
David Miller - Feb. 4, 2012, 11:20 p.m.
From: Shawn Lu <shawn.lu@ericsson.com>
Date: Sat, 4 Feb 2012 14:38:09 -0800

> 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>

Applied and queued up for -stable, thanks.
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Patch

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;