net: skb->rtable accessor

Define skb_rtable(const struct sk_buff *skb) accessor to get rtable from skb

Delete skb->rtable field

Setting rtable is not allowed, just set dst instead as rtable is an alias.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/netfilter/nf_nat_helper.c b/net/ipv4/netfilter/nf_nat_helper.c
index cf7a42b..155c008 100644
--- a/net/ipv4/netfilter/nf_nat_helper.c
+++ b/net/ipv4/netfilter/nf_nat_helper.c
@@ -140,7 +140,7 @@
 			 const char *rep_buffer,
 			 unsigned int rep_len)
 {
-	struct rtable *rt = skb->rtable;
+	struct rtable *rt = skb_rtable(skb);
 	struct iphdr *iph;
 	struct tcphdr *tcph;
 	int oldlen, datalen;
@@ -218,7 +218,7 @@
 			 const char *rep_buffer,
 			 unsigned int rep_len)
 {
-	struct rtable *rt = skb->rtable;
+	struct rtable *rt = skb_rtable(skb);
 	struct iphdr *iph;
 	struct udphdr *udph;
 	int datalen, oldlen;