[PATCH 3.16.y-ckt 082/170] gre: Use inner mac length when computing tunnel length

[Luis Henriques]

3.16.7-ckt1 -stable review patch.  If anyone has any objections, please let me know.

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

From: Tom Herbert <therbert at google.com>

commit 14051f0452a2c26a3f4791e6ad6a435e8f1945ff upstream.

Currently, skb_inner_network_header is used but this does not account
for Ethernet header for ETH_P_TEB. Use skb_inner_mac_header which
handles TEB and also should work with IP encapsulation in which case
inner mac and inner network headers are the same.

Tested: Ran TCP_STREAM over GRE, worked as expected.

Signed-off-by: Tom Herbert <therbert at google.com>
Acked-by: Alexander Duyck <alexander.h.duyck at redhat.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 | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv4/gre_offload.c b/net/ipv4/gre_offload.c
index f0bdd47bbbcb..32041ecbeafb 100644
--- a/net/ipv4/gre_offload.c
+++ b/net/ipv4/gre_offload.c
@@ -51,7 +51,7 @@ static struct sk_buff *gre_gso_segment(struct sk_buff *skb,
 
 	greh = (struct gre_base_hdr *)skb_transport_header(skb);
 
-	ghl = skb_inner_network_header(skb) - skb_transport_header(skb);
+	ghl = skb_inner_mac_header(skb) - skb_transport_header(skb);
 	if (unlikely(ghl < sizeof(*greh)))
 		goto out;
 
-- 
2.1.0