[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, 3 insertions, 4 deletions

diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c
index 514a40b7fc7f..17ad69e90e48 100644
--- a/net/dccp/ipv4.c
+++ b/net/dccp/ipv4.c
@@ -450,7 +450,7 @@ static struct dst_entry* dccp_v4_route_skb(struct sock *sk,
                                            struct sk_buff *skb)
 {
         struct rtable *rt;
-        struct flowi fl = { .oif = ((struct rtable *)skb->dst)->rt_iif,
+        struct flowi fl = { .oif = skb->rtable->rt_iif,
                             .nl_u = { .ip4_u =
                                       { .daddr = ip_hdr(skb)->saddr,
                                         .saddr = ip_hdr(skb)->daddr,
@@ -511,7 +511,7 @@ static void dccp_v4_ctl_send_reset(struct sock *sk, struct sk_buff *rxskb)
         if (dccp_hdr(rxskb)->dccph_type == DCCP_PKT_RESET)
                 return;
 
-        if (((struct rtable *)rxskb->dst)->rt_type != RTN_LOCAL)
+        if (rxskb->rtable->rt_type != RTN_LOCAL)
                 return;
 
         dst = dccp_v4_route_skb(dccp_v4_ctl_socket->sk, rxskb);
@@ -563,8 +563,7 @@ int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
         struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
 
         /* Never answer to DCCP_PKT_REQUESTs 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))
                 return 0;       /* discard, don't send a reset here */
 
         if (dccp_bad_service_code(sk, service)) {