[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/ipconfig.c b/net/ipv4/ipconfig.c
index 6b91c9f..4e19ee0 100644
--- a/net/ipv4/ipconfig.c
+++ b/net/ipv4/ipconfig.c
@@ -432,7 +432,7 @@
 		goto drop;
 
 	/* Basic sanity checks can be done without the lock.  */
-	rarp = (struct arphdr *)skb->h.raw;
+	rarp = (struct arphdr *)skb_transport_header(skb);
 
 	/* If this test doesn't pass, it's not IP, or we should
 	 * ignore it anyway.
@@ -455,7 +455,7 @@
 		goto drop;
 
 	/* OK, it is all there and looks valid, process... */
-	rarp = (struct arphdr *)skb->h.raw;
+	rarp = (struct arphdr *)skb_transport_header(skb);
 	rarp_ptr = (unsigned char *) (rarp + 1);
 
 	/* One reply at a time, please. */