[SCTP]: Introduce sctp_hdr()

For consistency with all the other skb->h.raw accessors.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sctp/input.c b/net/sctp/input.c
index 9311b5d..3a322c5 100644
--- a/net/sctp/input.c
+++ b/net/sctp/input.c
@@ -79,14 +79,10 @@
 /* Calculate the SCTP checksum of an SCTP packet.  */
 static inline int sctp_rcv_checksum(struct sk_buff *skb)
 {
-	struct sctphdr *sh;
-	__u32 cmp, val;
 	struct sk_buff *list = skb_shinfo(skb)->frag_list;
-
-	sh = (struct sctphdr *) skb->h.raw;
-	cmp = ntohl(sh->checksum);
-
-	val = sctp_start_cksum((__u8 *)sh, skb_headlen(skb));
+	struct sctphdr *sh = sctp_hdr(skb);
+	__u32 cmp = ntohl(sh->checksum);
+	__u32 val = sctp_start_cksum((__u8 *)sh, skb_headlen(skb));
 
 	for (; list; list = list->next)
 		val = sctp_update_cksum((__u8 *)list->data, skb_headlen(list),
@@ -138,7 +134,7 @@
 	if (skb_linearize(skb))
 		goto discard_it;
 
-	sh = (struct sctphdr *) skb->h.raw;
+	sh = sctp_hdr(skb);
 
 	/* Pull up the IP and SCTP headers. */
 	__skb_pull(skb, skb_transport_offset(skb));
@@ -905,7 +901,7 @@
 	struct sctp_association *asoc;
 	union sctp_addr addr;
 	union sctp_addr *paddr = &addr;
-	struct sctphdr *sh = (struct sctphdr *) skb->h.raw;
+	struct sctphdr *sh = sctp_hdr(skb);
 	sctp_chunkhdr_t *ch;
 	union sctp_params params;
 	sctp_init_chunk_t *init;