net: skb->dst accessors

Define three accessors to get/set dst attached to a skb

struct dst_entry *skb_dst(const struct sk_buff *skb)

void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst)

void skb_dst_drop(struct sk_buff *skb)
This one should replace occurrences of :
dst_release(skb->dst)
skb->dst = NULL;

Delete skb->dst field

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/ip6_route.h b/include/net/ip6_route.h
index 5f53db7..0e1b8ae 100644
--- a/include/net/ip6_route.h
+++ b/include/net/ip6_route.h
@@ -142,7 +142,7 @@
 
 static inline int ipv6_unicast_destination(struct sk_buff *skb)
 {
-	struct rt6_info *rt = (struct rt6_info *) skb->dst;
+	struct rt6_info *rt = (struct rt6_info *) skb_dst(skb);
 
 	return rt->rt6i_flags & RTF_LOCAL;
 }