[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/include/linux/icmpv6.h b/include/linux/icmpv6.h
index 0b5ba5e..7c5e981 100644
--- a/include/linux/icmpv6.h
+++ b/include/linux/icmpv6.h
@@ -80,7 +80,7 @@
 
 static inline struct icmp6hdr *icmp6_hdr(const struct sk_buff *skb)
 {
-	return (struct icmp6hdr *)skb->h.raw;
+	return (struct icmp6hdr *)skb_transport_header(skb);
 }
 #endif