netfilter: Push struct net down into nf_afinfo.reroute

The network namespace is needed when routing a packet.
Stop making nf_afinfo.reroute guess which network namespace
is the proper namespace to route the packet in.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

include/linux/netfilter.h

@@ -283,7 +283,7 @@ struct nf_afinfo {
 				 struct flowi *fl, bool strict);
 	void		(*saveroute)(const struct sk_buff *skb,
 				     struct nf_queue_entry *entry);
-	int		(*reroute)(struct sk_buff *skb,
+	int		(*reroute)(struct net *net, struct sk_buff *skb,
 				   const struct nf_queue_entry *entry);
 	int		route_key_size;
 };

net/ipv4/netfilter.c

@@ -104,7 +104,7 @@ static void nf_ip_saveroute(const struct sk_buff *skb,
 	}
 }
 
-static int nf_ip_reroute(struct sk_buff *skb,
+static int nf_ip_reroute(struct net *net, struct sk_buff *skb,
 			 const struct nf_queue_entry *entry)
 {
 	const struct ip_rt_info *rt_info = nf_queue_entry_reroute(entry);

net/ipv6/netfilter.c

@@ -93,7 +93,7 @@ static void nf_ip6_saveroute(const struct sk_buff *skb,
 	}
 }
 
-static int nf_ip6_reroute(struct sk_buff *skb,
+static int nf_ip6_reroute(struct net *net, struct sk_buff *skb,
 			  const struct nf_queue_entry *entry)
 {
 	struct ip6_rt_info *rt_info = nf_queue_entry_reroute(entry);

net/netfilter/nf_queue.c

@@ -199,7 +199,7 @@ void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict)
 
 	if (verdict == NF_ACCEPT) {
 		afinfo = nf_get_afinfo(entry->state.pf);
-		if (!afinfo || afinfo->reroute(skb, entry) < 0)
+		if (!afinfo || afinfo->reroute(entry->state.net, skb, entry) < 0)
 			verdict = NF_DROP;
 	}