[IPV4]: Add 'rtable' field in struct sk_buff to alias 'dst' and avoid casts

(Anonymous) unions can help us to avoid ugly casts.

A common cast it the (struct rtable *)skb->dst one.

Defining an union like  :
union {
     struct dst_entry *dst;
     struct rtable *rtable;
};
permits to use skb->rtable in place.

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 5 insertions, 2 deletions

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index bbd8d0027e2f..7beb239d2ee0 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -256,7 +256,10 @@ struct sk_buff {
         ktime_t                 tstamp;
         struct net_device       *dev;
 
-        struct  dst_entry       *dst;
+        union {
+                struct  dst_entry       *dst;
+                struct  rtable          *rtable;
+        };
         struct  sec_path        *sp;
 
         /*
diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h
index 89cd011edb99..8660cb0fa0dd 100644
--- a/include/net/inet_sock.h
+++ b/include/net/inet_sock.h
@@ -195,7 +195,7 @@ static inline int inet_sk_ehashfn(const struct sock *sk)
 
 static inline int inet_iif(const struct sk_buff *skb)
 {
-        return ((struct rtable *)skb->dst)->rt_iif;
+        return skb->rtable->rt_iif;
 }
 
 #endif  /* _INET_SOCK_H */