[PATCH 3.16.y-ckt 159/168] gre: Set inner mac header in gro complete

[Luis Henriques]

3.16.7-ckt3 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Tom Herbert <therbert at google.com>

commit 6fb2a756739aa507c1fd5b8126f0bfc2f070dc46 upstream.

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 at stwm.de>
Signed-off-by: Tom Herbert <therbert at google.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 net/ipv4/gre_offload.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/ipv4/gre_offload.c b/net/ipv4/gre_offload.c
index 32041ecbeafb..4ae6b52751e9 100644
--- 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;
 }
 
-- 
2.1.3