[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/ipv6.c b/net/sctp/ipv6.c
index 001be2d..0992bc5 100644
--- a/net/sctp/ipv6.c
+++ b/net/sctp/ipv6.c
@@ -390,7 +390,7 @@
 	addr->v6.sin6_flowinfo = 0; /* FIXME */
 	addr->v6.sin6_scope_id = ((struct inet6_skb_parm *)skb->cb)->iif;
 
-	sh = (struct sctphdr *) skb->h.raw;
+	sh = sctp_hdr(skb);
 	if (is_saddr) {
 		*port  = sh->source;
 		from = &ipv6_hdr(skb)->saddr;
@@ -765,7 +765,7 @@
 	if (msgname) {
 		sctp_inet6_msgname(msgname, addr_len);
 		sin6 = (struct sockaddr_in6 *)msgname;
-		sh = (struct sctphdr *)skb->h.raw;
+		sh = sctp_hdr(skb);
 		sin6->sin6_port = sh->source;
 
 		/* Map ipv4 address into v4-mapped-on-v6 address. */