openvswitch: Support conntrack zone limit

Currently, nf_conntrack_max is used to limit the maximum number of
conntrack entries in the conntrack table for every network namespace.
For the VMs and containers that reside in the same namespace,
they share the same conntrack table, and the total # of conntrack entries
for all the VMs and containers are limited by nf_conntrack_max.  In this
case, if one of the VM/container abuses the usage the conntrack entries,
it blocks the others from committing valid conntrack entries into the
conntrack table.  Even if we can possibly put the VM in different network
namespace, the current nf_conntrack_max configuration is kind of rigid
that we cannot limit different VM/container to have different # conntrack
entries.

To address the aforementioned issue, this patch proposes to have a
fine-grained mechanism that could further limit the # of conntrack entries
per-zone.  For example, we can designate different zone to different VM,
and set conntrack limit to each zone.  By providing this isolation, a
mis-behaved VM only consumes the conntrack entries in its own zone, and
it will not influence other well-behaved VMs.  Moreover, the users can
set various conntrack limit to different zone based on their preference.

The proposed implementation utilizes Netfilter's nf_conncount backend
to count the number of connections in a particular zone.  If the number of
connection is above a configured limitation, ovs will return ENOMEM to the
userspace.  If userspace does not configure the zone limit, the limit
defaults to zero that is no limitation, which is backward compatible to
the behavior without this patch.

The following high leve APIs are provided to the userspace:
  - OVS_CT_LIMIT_CMD_SET:
    * set default connection limit for all zones
    * set the connection limit for a particular zone
  - OVS_CT_LIMIT_CMD_DEL:
    * remove the connection limit for a particular zone
  - OVS_CT_LIMIT_CMD_GET:
    * get the default connection limit for all zones
    * get the connection limit for a particular zone

Signed-off-by: Yi-Hung Wei <yihung.wei@gmail.com>
Acked-by: Pravin B Shelar <pshelar@ovn.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 550 insertions, 1 deletions

diff --git a/net/openvswitch/conntrack.c b/net/openvswitch/conntrack.c
index 02fc343feb66..284aca2a252d 100644
--- a/net/openvswitch/conntrack.c
+++ b/net/openvswitch/conntrack.c
@@ -16,8 +16,11 @@
 #include <linux/tcp.h>
 #include <linux/udp.h>
 #include <linux/sctp.h>
+#include <linux/static_key.h>
 #include <net/ip.h>
+#include <net/genetlink.h>
 #include <net/netfilter/nf_conntrack_core.h>
+#include <net/netfilter/nf_conntrack_count.h>
 #include <net/netfilter/nf_conntrack_helper.h>
 #include <net/netfilter/nf_conntrack_labels.h>
 #include <net/netfilter/nf_conntrack_seqadj.h>
@@ -76,6 +79,31 @@ struct ovs_conntrack_info {
 #endif
 };
 
+#if	IS_ENABLED(CONFIG_NETFILTER_CONNCOUNT)
+#define OVS_CT_LIMIT_UNLIMITED	0
+#define OVS_CT_LIMIT_DEFAULT OVS_CT_LIMIT_UNLIMITED
+#define CT_LIMIT_HASH_BUCKETS 512
+static DEFINE_STATIC_KEY_FALSE(ovs_ct_limit_enabled);
+
+struct ovs_ct_limit {
+	/* Elements in ovs_ct_limit_info->limits hash table */
+	struct hlist_node hlist_node;
+	struct rcu_head rcu;
+	u16 zone;
+	u32 limit;
+};
+
+struct ovs_ct_limit_info {
+	u32 default_limit;
+	struct hlist_head *limits;
+	struct nf_conncount_data *data;
+};
+
+static const struct nla_policy ct_limit_policy[OVS_CT_LIMIT_ATTR_MAX + 1] = {
+	[OVS_CT_LIMIT_ATTR_ZONE_LIMIT] = { .type = NLA_NESTED, },
+};
+#endif
+
 static bool labels_nonzero(const struct ovs_key_ct_labels *labels);
 
 static void __ovs_ct_free_action(struct ovs_conntrack_info *ct_info);
@@ -1036,6 +1064,89 @@ static bool labels_nonzero(const struct ovs_key_ct_labels *labels)
 	return false;
 }
 
+#if	IS_ENABLED(CONFIG_NETFILTER_CONNCOUNT)
+static struct hlist_head *ct_limit_hash_bucket(
+	const struct ovs_ct_limit_info *info, u16 zone)
+{
+	return &info->limits[zone & (CT_LIMIT_HASH_BUCKETS - 1)];
+}
+
+/* Call with ovs_mutex */
+static void ct_limit_set(const struct ovs_ct_limit_info *info,
+			 struct ovs_ct_limit *new_ct_limit)
+{
+	struct ovs_ct_limit *ct_limit;
+	struct hlist_head *head;
+
+	head = ct_limit_hash_bucket(info, new_ct_limit->zone);
+	hlist_for_each_entry_rcu(ct_limit, head, hlist_node) {
+		if (ct_limit->zone == new_ct_limit->zone) {
+			hlist_replace_rcu(&ct_limit->hlist_node,
+					  &new_ct_limit->hlist_node);
+			kfree_rcu(ct_limit, rcu);
+			return;
+		}
+	}
+
+	hlist_add_head_rcu(&new_ct_limit->hlist_node, head);
+}
+
+/* Call with ovs_mutex */
+static void ct_limit_del(const struct ovs_ct_limit_info *info, u16 zone)
+{
+	struct ovs_ct_limit *ct_limit;
+	struct hlist_head *head;
+	struct hlist_node *n;
+
+	head = ct_limit_hash_bucket(info, zone);
+	hlist_for_each_entry_safe(ct_limit, n, head, hlist_node) {
+		if (ct_limit->zone == zone) {
+			hlist_del_rcu(&ct_limit->hlist_node);
+			kfree_rcu(ct_limit, rcu);
+			return;
+		}
+	}
+}
+
+/* Call with RCU read lock */
+static u32 ct_limit_get(const struct ovs_ct_limit_info *info, u16 zone)
+{
+	struct ovs_ct_limit *ct_limit;
+	struct hlist_head *head;
+
+	head = ct_limit_hash_bucket(info, zone);
+	hlist_for_each_entry_rcu(ct_limit, head, hlist_node) {
+		if (ct_limit->zone == zone)
+			return ct_limit->limit;
+	}
+
+	return info->default_limit;
+}
+
+static int ovs_ct_check_limit(struct net *net,
+			      const struct ovs_conntrack_info *info,
+			      const struct nf_conntrack_tuple *tuple)
+{
+	struct ovs_net *ovs_net = net_generic(net, ovs_net_id);
+	const struct ovs_ct_limit_info *ct_limit_info = ovs_net->ct_limit_info;
+	u32 per_zone_limit, connections;
+	u32 conncount_key;
+
+	conncount_key = info->zone.id;
+
+	per_zone_limit = ct_limit_get(ct_limit_info, info->zone.id);
+	if (per_zone_limit == OVS_CT_LIMIT_UNLIMITED)
+		return 0;
+
+	connections = nf_conncount_count(net, ct_limit_info->data,
+					 &conncount_key, tuple, &info->zone);
+	if (connections > per_zone_limit)
+		return -ENOMEM;
+
+	return 0;
+}
+#endif
+
 /* Lookup connection and confirm if unconfirmed. */
 static int ovs_ct_commit(struct net *net, struct sw_flow_key *key,
 			 const struct ovs_conntrack_info *info,
@@ -1054,6 +1165,21 @@ static int ovs_ct_commit(struct net *net, struct sw_flow_key *key,
 	if (!ct)
 		return 0;
 
+#if	IS_ENABLED(CONFIG_NETFILTER_CONNCOUNT)
+	if (static_branch_unlikely(&ovs_ct_limit_enabled)) {
+		if (!nf_ct_is_confirmed(ct)) {
+			err = ovs_ct_check_limit(net, info,
+				&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
+			if (err) {
+				net_warn_ratelimited("openvswitch: zone: %u "
+					"execeeds conntrack limit\n",
+					info->zone.id);
+				return err;
+			}
+		}
+	}
+#endif
+
 	/* Set the conntrack event mask if given.  NEW and DELETE events have
 	 * their own groups, but the NFNLGRP_CONNTRACK_UPDATE group listener
 	 * typically would receive many kinds of updates.  Setting the event
@@ -1655,7 +1781,420 @@ static void __ovs_ct_free_action(struct ovs_conntrack_info *ct_info)
 		nf_ct_tmpl_free(ct_info->ct);
 }
 
-void ovs_ct_init(struct net *net)
+#if	IS_ENABLED(CONFIG_NETFILTER_CONNCOUNT)
+static int ovs_ct_limit_init(struct net *net, struct ovs_net *ovs_net)
+{
+	int i, err;
+
+	ovs_net->ct_limit_info = kmalloc(sizeof(*ovs_net->ct_limit_info),
+					 GFP_KERNEL);
+	if (!ovs_net->ct_limit_info)
+		return -ENOMEM;
+
+	ovs_net->ct_limit_info->default_limit = OVS_CT_LIMIT_DEFAULT;
+	ovs_net->ct_limit_info->limits =
+		kmalloc_array(CT_LIMIT_HASH_BUCKETS, sizeof(struct hlist_head),
+			      GFP_KERNEL);
+	if (!ovs_net->ct_limit_info->limits) {
+		kfree(ovs_net->ct_limit_info);
+		return -ENOMEM;
+	}
+
+	for (i = 0; i < CT_LIMIT_HASH_BUCKETS; i++)
+		INIT_HLIST_HEAD(&ovs_net->ct_limit_info->limits[i]);
+
+	ovs_net->ct_limit_info->data =
+		nf_conncount_init(net, NFPROTO_INET, sizeof(u32));
+
+	if (IS_ERR(ovs_net->ct_limit_info->data)) {
+		err = PTR_ERR(ovs_net->ct_limit_info->data);
+		kfree(ovs_net->ct_limit_info->limits);
+		kfree(ovs_net->ct_limit_info);
+		pr_err("openvswitch: failed to init nf_conncount %d\n", err);
+		return err;
+	}
+	return 0;
+}
+
+static void ovs_ct_limit_exit(struct net *net, struct ovs_net *ovs_net)
+{
+	const struct ovs_ct_limit_info *info = ovs_net->ct_limit_info;
+	int i;
+
+	nf_conncount_destroy(net, NFPROTO_INET, info->data);
+	for (i = 0; i < CT_LIMIT_HASH_BUCKETS; ++i) {
+		struct hlist_head *head = &info->limits[i];
+		struct ovs_ct_limit *ct_limit;
+
+		hlist_for_each_entry_rcu(ct_limit, head, hlist_node)
+			kfree_rcu(ct_limit, rcu);
+	}
+	kfree(ovs_net->ct_limit_info->limits);
+	kfree(ovs_net->ct_limit_info);
+}
+
+static struct sk_buff *
+ovs_ct_limit_cmd_reply_start(struct genl_info *info, u8 cmd,
+			     struct ovs_header **ovs_reply_header)
+{
+	struct ovs_header *ovs_header = info->userhdr;
+	struct sk_buff *skb;
+
+	skb = genlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!skb)
+		return ERR_PTR(-ENOMEM);
+
+	*ovs_reply_header = genlmsg_put(skb, info->snd_portid,
+					info->snd_seq,
+					&dp_ct_limit_genl_family, 0, cmd);
+
+	if (!*ovs_reply_header) {
+		nlmsg_free(skb);
+		return ERR_PTR(-EMSGSIZE);
+	}
+	(*ovs_reply_header)->dp_ifindex = ovs_header->dp_ifindex;
+
+	return skb;
+}
+
+static bool check_zone_id(int zone_id, u16 *pzone)
+{
+	if (zone_id >= 0 && zone_id <= 65535) {
+		*pzone = (u16)zone_id;
+		return true;
+	}
+	return false;
+}
+
+static int ovs_ct_limit_set_zone_limit(struct nlattr *nla_zone_limit,
+				       struct ovs_ct_limit_info *info)
+{
+	struct ovs_zone_limit *zone_limit;
+	int rem;
+	u16 zone;
+
+	rem = NLA_ALIGN(nla_len(nla_zone_limit));
+	zone_limit = (struct ovs_zone_limit *)nla_data(nla_zone_limit);
+
+	while (rem >= sizeof(*zone_limit)) {
+		if (unlikely(zone_limit->zone_id ==
+				OVS_ZONE_LIMIT_DEFAULT_ZONE)) {
+			ovs_lock();
+			info->default_limit = zone_limit->limit;
+			ovs_unlock();
+		} else if (unlikely(!check_zone_id(
+				zone_limit->zone_id, &zone))) {
+			OVS_NLERR(true, "zone id is out of range");
+		} else {
+			struct ovs_ct_limit *ct_limit;
+
+			ct_limit = kmalloc(sizeof(*ct_limit), GFP_KERNEL);
+			if (!ct_limit)
+				return -ENOMEM;
+
+			ct_limit->zone = zone;
+			ct_limit->limit = zone_limit->limit;
+
+			ovs_lock();
+			ct_limit_set(info, ct_limit);
+			ovs_unlock();
+		}
+		rem -= NLA_ALIGN(sizeof(*zone_limit));
+		zone_limit = (struct ovs_zone_limit *)((u8 *)zone_limit +
+				NLA_ALIGN(sizeof(*zone_limit)));
+	}
+
+	if (rem)
+		OVS_NLERR(true, "set zone limit has %d unknown bytes", rem);
+
+	return 0;
+}
+
+static int ovs_ct_limit_del_zone_limit(struct nlattr *nla_zone_limit,
+				       struct ovs_ct_limit_info *info)
+{
+	struct ovs_zone_limit *zone_limit;
+	int rem;
+	u16 zone;
+
+	rem = NLA_ALIGN(nla_len(nla_zone_limit));
+	zone_limit = (struct ovs_zone_limit *)nla_data(nla_zone_limit);
+
+	while (rem >= sizeof(*zone_limit)) {
+		if (unlikely(zone_limit->zone_id ==
+				OVS_ZONE_LIMIT_DEFAULT_ZONE)) {
+			ovs_lock();
+			info->default_limit = OVS_CT_LIMIT_DEFAULT;
+			ovs_unlock();
+		} else if (unlikely(!check_zone_id(
+				zone_limit->zone_id, &zone))) {
+			OVS_NLERR(true, "zone id is out of range");
+		} else {
+			ovs_lock();
+			ct_limit_del(info, zone);
+			ovs_unlock();
+		}
+		rem -= NLA_ALIGN(sizeof(*zone_limit));
+		zone_limit = (struct ovs_zone_limit *)((u8 *)zone_limit +
+				NLA_ALIGN(sizeof(*zone_limit)));
+	}
+
+	if (rem)
+		OVS_NLERR(true, "del zone limit has %d unknown bytes", rem);
+
+	return 0;
+}
+
+static int ovs_ct_limit_get_default_limit(struct ovs_ct_limit_info *info,
+					  struct sk_buff *reply)
+{
+	struct ovs_zone_limit zone_limit;
+	int err;
+
+	zone_limit.zone_id = OVS_ZONE_LIMIT_DEFAULT_ZONE;
+	zone_limit.limit = info->default_limit;
+	err = nla_put_nohdr(reply, sizeof(zone_limit), &zone_limit);
+	if (err)
+		return err;
+
+	return 0;
+}
+
+static int __ovs_ct_limit_get_zone_limit(struct net *net,
+					 struct nf_conncount_data *data,
+					 u16 zone_id, u32 limit,
+					 struct sk_buff *reply)
+{
+	struct nf_conntrack_zone ct_zone;
+	struct ovs_zone_limit zone_limit;
+	u32 conncount_key = zone_id;
+
+	zone_limit.zone_id = zone_id;
+	zone_limit.limit = limit;
+	nf_ct_zone_init(&ct_zone, zone_id, NF_CT_DEFAULT_ZONE_DIR, 0);
+
+	zone_limit.count = nf_conncount_count(net, data, &conncount_key, NULL,
+					      &ct_zone);
+	return nla_put_nohdr(reply, sizeof(zone_limit), &zone_limit);
+}
+
+static int ovs_ct_limit_get_zone_limit(struct net *net,
+				       struct nlattr *nla_zone_limit,
+				       struct ovs_ct_limit_info *info,
+				       struct sk_buff *reply)
+{
+	struct ovs_zone_limit *zone_limit;
+	int rem, err;
+	u32 limit;
+	u16 zone;
+
+	rem = NLA_ALIGN(nla_len(nla_zone_limit));
+	zone_limit = (struct ovs_zone_limit *)nla_data(nla_zone_limit);
+
+	while (rem >= sizeof(*zone_limit)) {
+		if (unlikely(zone_limit->zone_id ==
+				OVS_ZONE_LIMIT_DEFAULT_ZONE)) {
+			err = ovs_ct_limit_get_default_limit(info, reply);
+			if (err)
+				return err;
+		} else if (unlikely(!check_zone_id(zone_limit->zone_id,
+							&zone))) {
+			OVS_NLERR(true, "zone id is out of range");
+		} else {
+			rcu_read_lock();
+			limit = ct_limit_get(info, zone);
+			rcu_read_unlock();
+
+			err = __ovs_ct_limit_get_zone_limit(
+				net, info->data, zone, limit, reply);
+			if (err)
+				return err;
+		}
+		rem -= NLA_ALIGN(sizeof(*zone_limit));
+		zone_limit = (struct ovs_zone_limit *)((u8 *)zone_limit +
+				NLA_ALIGN(sizeof(*zone_limit)));
+	}
+
+	if (rem)
+		OVS_NLERR(true, "get zone limit has %d unknown bytes", rem);
+
+	return 0;
+}
+
+static int ovs_ct_limit_get_all_zone_limit(struct net *net,
+					   struct ovs_ct_limit_info *info,
+					   struct sk_buff *reply)
+{
+	struct ovs_ct_limit *ct_limit;
+	struct hlist_head *head;
+	int i, err = 0;
+
+	err = ovs_ct_limit_get_default_limit(info, reply);
+	if (err)
+		return err;
+
+	rcu_read_lock();
+	for (i = 0; i < CT_LIMIT_HASH_BUCKETS; ++i) {
+		head = &info->limits[i];
+		hlist_for_each_entry_rcu(ct_limit, head, hlist_node) {
+			err = __ovs_ct_limit_get_zone_limit(net, info->data,
+				ct_limit->zone, ct_limit->limit, reply);
+			if (err)
+				goto exit_err;
+		}
+	}
+
+exit_err:
+	rcu_read_unlock();
+	return err;
+}
+
+static int ovs_ct_limit_cmd_set(struct sk_buff *skb, struct genl_info *info)
+{
+	struct nlattr **a = info->attrs;
+	struct sk_buff *reply;
+	struct ovs_header *ovs_reply_header;
+	struct ovs_net *ovs_net = net_generic(sock_net(skb->sk), ovs_net_id);
+	struct ovs_ct_limit_info *ct_limit_info = ovs_net->ct_limit_info;
+	int err;
+
+	reply = ovs_ct_limit_cmd_reply_start(info, OVS_CT_LIMIT_CMD_SET,
+					     &ovs_reply_header);
+	if (IS_ERR(reply))
+		return PTR_ERR(reply);
+
+	if (!a[OVS_CT_LIMIT_ATTR_ZONE_LIMIT]) {
+		err = -EINVAL;
+		goto exit_err;
+	}
+
+	err = ovs_ct_limit_set_zone_limit(a[OVS_CT_LIMIT_ATTR_ZONE_LIMIT],
+					  ct_limit_info);
+	if (err)
+		goto exit_err;
+
+	static_branch_enable(&ovs_ct_limit_enabled);
+
+	genlmsg_end(reply, ovs_reply_header);
+	return genlmsg_reply(reply, info);
+
+exit_err:
+	nlmsg_free(reply);
+	return err;
+}
+
+static int ovs_ct_limit_cmd_del(struct sk_buff *skb, struct genl_info *info)
+{
+	struct nlattr **a = info->attrs;
+	struct sk_buff *reply;
+	struct ovs_header *ovs_reply_header;
+	struct ovs_net *ovs_net = net_generic(sock_net(skb->sk), ovs_net_id);
+	struct ovs_ct_limit_info *ct_limit_info = ovs_net->ct_limit_info;
+	int err;
+
+	reply = ovs_ct_limit_cmd_reply_start(info, OVS_CT_LIMIT_CMD_DEL,
+					     &ovs_reply_header);
+	if (IS_ERR(reply))
+		return PTR_ERR(reply);
+
+	if (!a[OVS_CT_LIMIT_ATTR_ZONE_LIMIT]) {
+		err = -EINVAL;
+		goto exit_err;
+	}
+
+	err = ovs_ct_limit_del_zone_limit(a[OVS_CT_LIMIT_ATTR_ZONE_LIMIT],
+					  ct_limit_info);
+	if (err)
+		goto exit_err;
+
+	genlmsg_end(reply, ovs_reply_header);
+	return genlmsg_reply(reply, info);
+
+exit_err:
+	nlmsg_free(reply);
+	return err;
+}
+
+static int ovs_ct_limit_cmd_get(struct sk_buff *skb, struct genl_info *info)
+{
+	struct nlattr **a = info->attrs;
+	struct nlattr *nla_reply;
+	struct sk_buff *reply;
+	struct ovs_header *ovs_reply_header;
+	struct net *net = sock_net(skb->sk);
+	struct ovs_net *ovs_net = net_generic(net, ovs_net_id);
+	struct ovs_ct_limit_info *ct_limit_info = ovs_net->ct_limit_info;
+	int err;
+
+	reply = ovs_ct_limit_cmd_reply_start(info, OVS_CT_LIMIT_CMD_GET,
+					     &ovs_reply_header);
+	if (IS_ERR(reply))
+		return PTR_ERR(reply);
+
+	nla_reply = nla_nest_start(reply, OVS_CT_LIMIT_ATTR_ZONE_LIMIT);
+
+	if (a[OVS_CT_LIMIT_ATTR_ZONE_LIMIT]) {
+		err = ovs_ct_limit_get_zone_limit(
+			net, a[OVS_CT_LIMIT_ATTR_ZONE_LIMIT], ct_limit_info,
+			reply);
+		if (err)
+			goto exit_err;
+	} else {
+		err = ovs_ct_limit_get_all_zone_limit(net, ct_limit_info,
+						      reply);
+		if (err)
+			goto exit_err;
+	}
+
+	nla_nest_end(reply, nla_reply);
+	genlmsg_end(reply, ovs_reply_header);
+	return genlmsg_reply(reply, info);
+
+exit_err:
+	nlmsg_free(reply);
+	return err;
+}
+
+static struct genl_ops ct_limit_genl_ops[] = {
+	{ .cmd = OVS_CT_LIMIT_CMD_SET,
+		.flags = GENL_ADMIN_PERM, /* Requires CAP_NET_ADMIN
+					   * privilege. */
+		.policy = ct_limit_policy,
+		.doit = ovs_ct_limit_cmd_set,
+	},
+	{ .cmd = OVS_CT_LIMIT_CMD_DEL,
+		.flags = GENL_ADMIN_PERM, /* Requires CAP_NET_ADMIN
+					   * privilege. */
+		.policy = ct_limit_policy,
+		.doit = ovs_ct_limit_cmd_del,
+	},
+	{ .cmd = OVS_CT_LIMIT_CMD_GET,
+		.flags = 0,		  /* OK for unprivileged users. */
+		.policy = ct_limit_policy,
+		.doit = ovs_ct_limit_cmd_get,
+	},
+};
+
+static const struct genl_multicast_group ovs_ct_limit_multicast_group = {
+	.name = OVS_CT_LIMIT_MCGROUP,
+};
+
+struct genl_family dp_ct_limit_genl_family __ro_after_init = {
+	.hdrsize = sizeof(struct ovs_header),
+	.name = OVS_CT_LIMIT_FAMILY,
+	.version = OVS_CT_LIMIT_VERSION,
+	.maxattr = OVS_CT_LIMIT_ATTR_MAX,
+	.netnsok = true,
+	.parallel_ops = true,
+	.ops = ct_limit_genl_ops,
+	.n_ops = ARRAY_SIZE(ct_limit_genl_ops),
+	.mcgrps = &ovs_ct_limit_multicast_group,
+	.n_mcgrps = 1,
+	.module = THIS_MODULE,
+};
+#endif
+
+int ovs_ct_init(struct net *net)
 {
 	unsigned int n_bits = sizeof(struct ovs_key_ct_labels) * BITS_PER_BYTE;
 	struct ovs_net *ovs_net = net_generic(net, ovs_net_id);
@@ -1666,12 +2205,22 @@ void ovs_ct_init(struct net *net)
 	} else {
 		ovs_net->xt_label = true;
 	}
+
+#if	IS_ENABLED(CONFIG_NETFILTER_CONNCOUNT)
+	return ovs_ct_limit_init(net, ovs_net);
+#else
+	return 0;
+#endif
 }
 
 void ovs_ct_exit(struct net *net)
 {
 	struct ovs_net *ovs_net = net_generic(net, ovs_net_id);
 
+#if	IS_ENABLED(CONFIG_NETFILTER_CONNCOUNT)
+	ovs_ct_limit_exit(net, ovs_net);
+#endif
+
 	if (ovs_net->xt_label)
 		nf_connlabels_put(net);
 }