netfilter: netns nf_conntrack: pass netns pointer to L4 protocol's ->error hook

Again, it's deducible from skb, but we're going to use it for
nf_conntrack_checksum and statistics, so just pass it from upper layer.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index 5c96d97..251f020 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -703,11 +703,13 @@
 	/* It may be an special packet, error, unclean...
 	 * inverse of the return code tells to the netfilter
 	 * core what to do with the packet. */
-	if (l4proto->error != NULL &&
-	    (ret = l4proto->error(skb, dataoff, &ctinfo, pf, hooknum)) <= 0) {
-		NF_CT_STAT_INC_ATOMIC(error);
-		NF_CT_STAT_INC_ATOMIC(invalid);
-		return -ret;
+	if (l4proto->error != NULL) {
+		ret = l4proto->error(net, skb, dataoff, &ctinfo, pf, hooknum);
+		if (ret <= 0) {
+			NF_CT_STAT_INC_ATOMIC(error);
+			NF_CT_STAT_INC_ATOMIC(invalid);
+			return -ret;
+		}
 	}
 
 	ct = resolve_normal_ct(net, skb, dataoff, pf, protonum,