gre: Set inner mac header in gro complete

[ Upstream commit 6fb2a756739aa507c1fd5b8126f0bfc2f070dc46 ]

Set the inner mac header to point to the GRE payload when
doing GRO. This is needed if we proceed to send the packet
through GRE GSO which now uses the inner mac header instead
of inner network header to determine the length of encapsulation
headers.

Fixes: 14051f0452a2 ("gre: Use inner mac length when computing tunnel length")
Reported-by: Wolfgang Walter <linux@stwm.de>
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/ipv4/gre_offload.c b/net/ipv4/gre_offload.c
index dd73bea2a65f0f87ce4e4c391f388fd985fcea7f..657d80c0931a3cb9e99840c1c141bfb66dd412aa 100644 (file)
--- a/net/ipv4/gre_offload.c
+++ b/net/ipv4/gre_offload.c
@@ -279,6 +279,9 @@ static int gre_gro_complete(struct sk_buff *skb, int nhoff)
                err = ptype->callbacks.gro_complete(skb, nhoff + grehlen);
 
        rcu_read_unlock();
+
+       skb_set_inner_mac_header(skb, nhoff + grehlen);
+
        return err;
 }