| From | Greg Kroah-Hartman <> | Subject | [ 31/79] gre: Fix MTU sizing check for gretap tunnels | Date | Fri, 26 Jul 2013 13:47:21 -0700 |
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3.10-stable review patch. If anyone has any objections, please let me know.
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From: Alexander Duyck <alexander.h.duyck@intel.com>
[ 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 <alexander.h.duyck@intel.com> Reported-by: Cong Wang <amwang@redhat.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- 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)
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