[SK_BUFF] xfrm: Use skb_set_mac_header in the memmove cases

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/xfrm6_mode_tunnel.c b/net/ipv6/xfrm6_mode_tunnel.c
index 0bc866c..d2c560c 100644
--- a/net/ipv6/xfrm6_mode_tunnel.c
+++ b/net/ipv6/xfrm6_mode_tunnel.c
@@ -86,6 +86,7 @@
 static int xfrm6_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
 {
 	int err = -EINVAL;
+	const unsigned char *old_mac;
 
 	if (skb->nh.raw[IP6CB(skb)->nhoff] != IPPROTO_IPV6
 	    && skb->nh.raw[IP6CB(skb)->nhoff] != IPPROTO_IPIP)
@@ -107,8 +108,9 @@
 			ip6ip_ecn_decapsulate(skb);
 		skb->protocol = htons(ETH_P_IP);
 	}
-	skb->mac.raw = memmove(skb->data - skb->mac_len,
-			       skb->mac.raw, skb->mac_len);
+	old_mac = skb->mac.raw;
+	skb_set_mac_header(skb, -skb->mac_len);
+	memmove(skb->mac.raw, old_mac, skb->mac_len);
 	skb->nh.raw = skb->data;
 	err = 0;