ipv4/ipv6: Prepare for new route gateway semantics.

In the future the ipv4/ipv6 route gateway will take on two types
of values:

1) INADDR_ANY/IN6ADDR_ANY, for local network routes, and in this case
   the neighbour must be obtained using the destination address in
   ipv4/ipv6 header as the lookup key.

2) Everything else, the actual nexthop route address.

So if the gateway is not inaddr-any we use it, otherwise we must use
the packet's destination address.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 0 deletions

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index bcacf54e5418..4eeb8ce856e2 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1117,10 +1117,15 @@ static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst, const vo
         static const __be32 inaddr_any = 0;
         struct net_device *dev = dst->dev;
         const __be32 *pkey = daddr;
+        const struct rtable *rt;
         struct neighbour *n;
 
+        rt = (const struct rtable *) dst;
+
         if (dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT))
                 pkey = &inaddr_any;
+        else if (rt->rt_gateway)
+                pkey = (const __be32 *) &rt->rt_gateway;
 
         n = __ipv4_neigh_lookup(&arp_tbl, dev, *(__force u32 *)pkey);
         if (n)