[NETNS]: Pass correct namespace in ip_route_input_slow.

The packet on the input path always has a referrence to an input
network device it is passed from. Extract network namespace from it.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/route.c

@@ -1881,6 +1881,7 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 	__be32		spec_dst;
 	int		err = -EINVAL;
 	int		free_res = 0;
+	struct net    * net = dev->nd_net;
 
 	/* IP on this device is disabled. */
 
@@ -1911,7 +1912,7 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 	/*
 	 *	Now we are ready to route packet.
 	 */
-	if ((err = fib_lookup(&init_net, &fl, &res)) != 0) {
+	if ((err = fib_lookup(net, &fl, &res)) != 0) {
 		if (!IN_DEV_FORWARD(in_dev))
 			goto e_hostunreach;
 		goto no_route;
@@ -1926,7 +1927,7 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 	if (res.type == RTN_LOCAL) {
 		int result;
 		result = fib_validate_source(saddr, daddr, tos,
-					     init_net.loopback_dev->ifindex,
+					     net->loopback_dev->ifindex,
 					     dev, &spec_dst, &itag);
 		if (result < 0)
 			goto martian_source;
@@ -1988,7 +1989,7 @@ out:	return err;
 #endif
 	rth->rt_iif	=
 	rth->fl.iif	= dev->ifindex;
-	rth->u.dst.dev	= init_net.loopback_dev;
+	rth->u.dst.dev	= net->loopback_dev;
 	dev_hold(rth->u.dst.dev);
 	rth->idev	= in_dev_get(rth->u.dst.dev);
 	rth->rt_gateway	= daddr;