From 8c91e162e058bb91b7766f26f4d5823a21941026 Mon Sep 17 00:00:00 2001 From: Alexander Duyck Date: Thu, 11 Jul 2013 13:12:22 -0700 Subject: [PATCH] gre: Fix MTU sizing check for gretap tunnels 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 --- net/ipv4/ip_tunnel.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) 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) -- 2.7.4