ipv4: Pass struct net into ip_route_me_harder

Don't make ip_route_me_harder guess which network namespace
it is routing in, pass the network namespace in.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
diff --git a/net/ipv4/netfilter.c b/net/ipv4/netfilter.c
index 9e07e6f..c3776ff 100644
--- a/net/ipv4/netfilter.c
+++ b/net/ipv4/netfilter.c
@@ -17,9 +17,8 @@
 #include <net/netfilter/nf_queue.h>
 
 /* route_me_harder function, used by iptable_nat, iptable_mangle + ip_queue */
-int ip_route_me_harder(struct sk_buff *skb, unsigned int addr_type)
+int ip_route_me_harder(struct net *net, struct sk_buff *skb, unsigned int addr_type)
 {
-	struct net *net = dev_net(skb_dst(skb)->dev);
 	const struct iphdr *iph = ip_hdr(skb);
 	struct rtable *rt;
 	struct flowi4 fl4 = {};
@@ -116,7 +115,7 @@
 		      skb->mark == rt_info->mark &&
 		      iph->daddr == rt_info->daddr &&
 		      iph->saddr == rt_info->saddr))
-			return ip_route_me_harder(skb, RTN_UNSPEC);
+			return ip_route_me_harder(net, skb, RTN_UNSPEC);
 	}
 	return 0;
 }