From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alexander Duyck , Cong Wang , Eric Dumazet , "David S. Miller" Subject: [ 31/79] gre: Fix MTU sizing check for gretap tunnels Date: Fri, 26 Jul 2013 13:47:21 -0700 Message-Id: <20130726204725.184611789@linuxfoundation.org> In-Reply-To: <20130726204721.849052763@linuxfoundation.org> References: <20130726204721.849052763@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alexander Duyck [ Upstream commit 8c91e162e058bb91b7766f26f4d5823a21941026 ] 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 Reported-by: Cong Wang Acked-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv4/ip_tunnel.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/ipv4/ip_tunnel.c +++ b/net/ipv4/ip_tunnel.c @@ -490,7 +490,7 @@ static int tnl_update_pmtu(struct net_de 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)