[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/econet/af_econet.c b/net/econet/af_econet.c
index dcc2e4b..78993dad 100644
--- a/net/econet/af_econet.c
+++ b/net/econet/af_econet.c
@@ -943,7 +943,7 @@
 		printk(KERN_DEBUG "AUN: recvfrom() error %d\n", -err);
 	}
 
-	data = skb->h.raw + sizeof(struct udphdr);
+	data = skb_transport_header(skb) + sizeof(struct udphdr);
 	ah = (struct aunhdr *)data;
 	len = skb->len - sizeof(struct udphdr);
 	ip = ip_hdr(skb);