[SK_BUFF]: Introduce skb_transport_header(skb)

For the places where we need a pointer to the transport header, it is
still legal to touch skb->h.raw directly if just adding to,
subtracting from or setting it to another layer header.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/xfrm4_mode_beet.c b/net/ipv4/xfrm4_mode_beet.c
index 32fcfc0..591f0f1 100644
--- a/net/ipv4/xfrm4_mode_beet.c
+++ b/net/ipv4/xfrm4_mode_beet.c
@@ -51,7 +51,7 @@
 
 		BUG_ON(optlen < 0);
 
-		ph = (struct ip_beet_phdr *)skb->h.raw;
+		ph = (struct ip_beet_phdr *)skb_transport_header(skb);
 		ph->padlen = 4 - (optlen & 4);
 		ph->hdrlen = optlen / 8;
 		ph->nexthdr = top_iph->protocol;