ipv4: Kill rt->rt_oif

Never actually used.

It was being set on output routes to the original OIF specified in the
flow key used for the lookup.

Adjust the only user, ipmr_rt_fib_lookup(), for greater correctness of
the flowi4_oif and flowi4_iif values, thanks to feedback from Julian
Anastasov.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/net/route.h

@@ -50,7 +50,6 @@ struct rtable {
 
 	int			rt_route_iif;
 	int			rt_iif;
-	int			rt_oif;
 
 	/* Info on neighbour */
 	__be32			rt_gateway;

net/ipv4/ipmr.c

@@ -1795,8 +1795,11 @@ static struct mr_table *ipmr_rt_fib_lookup(struct net *net, struct sk_buff *skb)
 		.daddr = iph->daddr,
 		.saddr = iph->saddr,
 		.flowi4_tos = RT_TOS(iph->tos),
-		.flowi4_oif = rt->rt_oif,
-		.flowi4_iif = rt->rt_iif,
+		.flowi4_oif = (rt_is_output_route(rt) ?
+			       skb->dev->ifindex : 0),
+		.flowi4_iif = (rt_is_output_route(rt) ?
+			       net->loopback_dev->ifindex :
+			       skb->dev->ifindex),
 		.flowi4_mark = skb->mark,
 	};
 	struct mr_table *mrt;

net/ipv4/route.c

@@ -1332,7 +1332,6 @@ static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 	rth->rt_type	= RTN_MULTICAST;
 	rth->rt_route_iif = dev->ifindex;
 	rth->rt_iif	= dev->ifindex;
-	rth->rt_oif	= 0;
 	rth->rt_pmtu	= 0;
 	rth->rt_gateway	= 0;
 	rth->fi = NULL;
@@ -1463,7 +1462,6 @@ static int __mkroute_input(struct sk_buff *skb,
 	rth->rt_type = res->type;
 	rth->rt_route_iif = in_dev->dev->ifindex;
 	rth->rt_iif 	= in_dev->dev->ifindex;
-	rth->rt_oif 	= 0;
 	rth->rt_pmtu	= 0;
 	rth->rt_gateway	= 0;
 	rth->fi = NULL;
@@ -1642,7 +1640,6 @@ out:	return err;
 	rth->rt_type	= res.type;
 	rth->rt_route_iif = dev->ifindex;
 	rth->rt_iif	= dev->ifindex;
-	rth->rt_oif	= 0;
 	rth->rt_pmtu	= 0;
 	rth->rt_gateway	= 0;
 	rth->fi = NULL;
@@ -1808,7 +1805,6 @@ static struct rtable *__mkroute_output(const struct fib_result *res,
 	rth->rt_type	= type;
 	rth->rt_route_iif = 0;
 	rth->rt_iif	= orig_oif ? : dev_out->ifindex;
-	rth->rt_oif	= orig_oif;
 	rth->rt_pmtu	= 0;
 	rth->rt_gateway = 0;
 	rth->fi = NULL;
@@ -2085,7 +2081,6 @@ struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_or
 
 		rt->rt_route_iif = ort->rt_route_iif;
 		rt->rt_iif = ort->rt_iif;
-		rt->rt_oif = ort->rt_oif;
 		rt->rt_pmtu = ort->rt_pmtu;
 
 		rt->rt_genid = rt_genid(net);

net/ipv4/xfrm4_policy.c

@@ -81,7 +81,6 @@ static int xfrm4_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
 
 	xdst->u.rt.rt_route_iif = fl4->flowi4_iif;
 	xdst->u.rt.rt_iif = fl4->flowi4_iif;
-	xdst->u.rt.rt_oif = fl4->flowi4_oif;
 
 	xdst->u.dst.dev = dev;
 	dev_hold(dev);