[SK_BUFF]: Introduce ip_hdr(), remove skb->nh.iph

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/netfilter/xt_length.c b/net/netfilter/xt_length.c
index 32fb998..65fdb21 100644
--- a/net/netfilter/xt_length.c
+++ b/net/netfilter/xt_length.c
@@ -31,7 +31,7 @@
       int *hotdrop)
 {
 	const struct xt_length_info *info = matchinfo;
-	u_int16_t pktlen = ntohs(skb->nh.iph->tot_len);
+	u_int16_t pktlen = ntohs(ip_hdr(skb)->tot_len);
 
 	return (pktlen >= info->min && pktlen <= info->max) ^ info->invert;
 }