act_connmark: Remember the struct net instead of guessing it.

Stop guessing the struct net instead of remember it.  Guessing is just
silly and will be problematic in the future when I implement routes
between network namespaces.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

include/net/tc_act/tc_connmark.h

@@ -5,6 +5,7 @@
 
 struct tcf_connmark_info {
 	struct tcf_common common;
+	struct net *net;
 	u16 zone;
 };
 

net/sched/act_connmark.c

@@ -74,7 +74,7 @@ static int tcf_connmark(struct sk_buff *skb, const struct tc_action *a,
 	zone.id = ca->zone;
 	zone.dir = NF_CT_DEFAULT_ZONE_DIR;
 
-	thash = nf_conntrack_find_get(dev_net(skb->dev), &zone, &tuple);
+	thash = nf_conntrack_find_get(ca->net, &zone, &tuple);
 	if (!thash)
 		goto out;
 
@@ -119,6 +119,7 @@ static int tcf_connmark_init(struct net *net, struct nlattr *nla,
 
 		ci = to_connmark(a);
 		ci->tcf_action = parm->action;
+		ci->net = net;
 		ci->zone = parm->zone;
 
 		tcf_hash_insert(a);