[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>

1 files changed, 2 insertions, 3 deletions

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 3873c4dbeae..a79e324638e 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -552,7 +552,7 @@ static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb)
         if (th->rst)
                 return;
 
-        if (((struct rtable *)skb->dst)->rt_type != RTN_LOCAL)
+        if (skb->rtable->rt_type != RTN_LOCAL)
                 return;
 
         /* Swap the send and the receive. */
@@ -1262,8 +1262,7 @@ int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
 #endif
 
         /* Never answer to SYNs send to broadcast or multicast */
-        if (((struct rtable *)skb->dst)->rt_flags &
-            (RTCF_BROADCAST | RTCF_MULTICAST))
+        if (skb->rtable->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
                 goto drop;
 
         /* TW buckets are converted to open requests without