ipv4: Change rt->rt_iif encoding.

On input packet processing, rt->rt_iif will be zero if we should
use skb->dev->ifindex.

Since we access rt->rt_iif consistently via inet_iif(), that is
the only spot whose interpretation have to adjust.

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

1 files changed, 5 insertions, 1 deletions

diff --git a/include/net/route.h b/include/net/route.h
index 60d611dc5cee..c29ef2733f2d 100644
--- a/include/net/route.h
+++ b/include/net/route.h
@@ -277,7 +277,11 @@ static inline struct rtable *ip_route_newports(struct flowi4 *fl4, struct rtable
 
 static inline int inet_iif(const struct sk_buff *skb)
 {
-        return skb_rtable(skb)->rt_iif;
+        int iif = skb_rtable(skb)->rt_iif;
+
+        if (iif)
+                return iif;
+        return skb->skb_iif;
 }
 
 extern int sysctl_ip_default_ttl;