[GRE]: Fix hardware checksum modification

The skb_postpull_rcsum introduced a bug to the checksum modification.
Although the length pulled is offset bytes, the origin of the pulling
is the GRE header, not the IP header.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 1 deletions

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index a4c347c3b8e3..46f9d9cf7a5f 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -618,7 +618,7 @@ static int ipgre_rcv(struct sk_buff *skb)
 
                 skb->mac.raw = skb->nh.raw;
                 skb->nh.raw = __pskb_pull(skb, offset);
-                skb_postpull_rcsum(skb, skb->mac.raw, offset);
+                skb_postpull_rcsum(skb, skb->h.raw, offset);
                 memset(&(IPCB(skb)->opt), 0, sizeof(struct ip_options));
                 skb->pkt_type = PACKET_HOST;
 #ifdef CONFIG_NET_IPGRE_BROADCAST