1 files changed, 34 insertions, 4 deletions

diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index 76613f5a55c0..ed86a3be678e 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -404,19 +404,49 @@ static void __nf_conntrack_hash_insert(struct nf_conn *ct,
 			   &net->ct.hash[repl_hash]);
 }
 
-void nf_conntrack_hash_insert(struct nf_conn *ct)
+int
+nf_conntrack_hash_check_insert(struct nf_conn *ct)
 {
 	struct net *net = nf_ct_net(ct);
 	unsigned int hash, repl_hash;
+	struct nf_conntrack_tuple_hash *h;
+	struct hlist_nulls_node *n;
 	u16 zone;
 
 	zone = nf_ct_zone(ct);
-	hash = hash_conntrack(net, zone, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
-	repl_hash = hash_conntrack(net, zone, &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
+	hash = hash_conntrack(net, zone,
+			      &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
+	repl_hash = hash_conntrack(net, zone,
+				   &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
+
+	spin_lock_bh(&nf_conntrack_lock);
 
+	/* See if there's one in the list already, including reverse */
+	hlist_nulls_for_each_entry(h, n, &net->ct.hash[hash], hnnode)
+		if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
+				      &h->tuple) &&
+		    zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)))
+			goto out;
+	hlist_nulls_for_each_entry(h, n, &net->ct.hash[repl_hash], hnnode)
+		if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple,
+				      &h->tuple) &&
+		    zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)))
+			goto out;
+
+	add_timer(&ct->timeout);
+	nf_conntrack_get(&ct->ct_general);
 	__nf_conntrack_hash_insert(ct, hash, repl_hash);
+	NF_CT_STAT_INC(net, insert);
+	spin_unlock_bh(&nf_conntrack_lock);
+
+	return 0;
+
+out:
+	NF_CT_STAT_INC(net, insert_failed);
+	spin_unlock_bh(&nf_conntrack_lock);
+	return -EEXIST;
 }
-EXPORT_SYMBOL_GPL(nf_conntrack_hash_insert);
+EXPORT_SYMBOL_GPL(nf_conntrack_hash_check_insert);
 
 /* Confirm a connection given skb; places it in hash table */
 int