From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Duyck Subject: [PATCH net] gre: Fix MTU sizing check for gretap tunnels Date: Thu, 11 Jul 2013 13:12:22 -0700 Message-ID: <20130711201152.8775.40579.stgit@ahduyck-hc1.jf.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: pshelar@nicira.com, eric.dumazet@gmail.com, jesse@nicira.com, davem@davemloft.net To: netdev@vger.kernel.org Return-path: Received: from mga14.intel.com ([143.182.124.37]:56553 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750734Ab3GKUHy (ORCPT ); Thu, 11 Jul 2013 16:07:54 -0400 Sender: netdev-owner@vger.kernel.org List-ID: This change fixes an MTU sizing issue seen with gretap tunnels when non-gso packets are sent from the interface. In my case I was able to reproduce the issue by simply sending a ping of 1421 bytes with the gretap interface created on a device with a standard 1500 mtu. This fix is based on the fact that the tunnel mtu is already adjusted by dev->hard_header_len so it would make sense that any packets being compared against that mtu should also be adjusted by hard_header_len and the tunnel header instead of just the tunnel header. Signed-off-by: Alexander Duyck --- net/ipv4/ip_tunnel.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c index 945734b..ca1cb2d 100644 --- a/net/ipv4/ip_tunnel.c +++ b/net/ipv4/ip_tunnel.c @@ -476,7 +476,7 @@ static int tnl_update_pmtu(struct net_device *dev, struct sk_buff *skb, struct rtable *rt, __be16 df) { struct ip_tunnel *tunnel = netdev_priv(dev); - int pkt_size = skb->len - tunnel->hlen; + int pkt_size = skb->len - tunnel->hlen - dev->hard_header_len; int mtu; if (df)