netfilter: move nf_ct_netns_get out of nf_conncount_init

This patch is to move nf_ct_netns_get() out of nf_conncount_init()
and let the consumers of nf_conncount decide if they want to turn
on netfilter conntrack.

It makes nf_conncount more flexible to be used in other places and
avoids netfilter conntrack turned on when using it in openvswitch
conntrack.
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

include/net/netfilter/nf_conntrack_count.h

@@ -15,10 +15,8 @@ struct nf_conncount_list {
 	unsigned int count;	/* length of list */
 };
 
-struct nf_conncount_data *nf_conncount_init(struct net *net, unsigned int family,
-					    unsigned int keylen);
-void nf_conncount_destroy(struct net *net, unsigned int family,
-			  struct nf_conncount_data *data);
+struct nf_conncount_data *nf_conncount_init(struct net *net, unsigned int keylen);
+void nf_conncount_destroy(struct net *net, struct nf_conncount_data *data);
 
 unsigned int nf_conncount_count(struct net *net,
 				struct nf_conncount_data *data,

net/netfilter/nf_conncount.c

@@ -522,11 +522,10 @@ unsigned int nf_conncount_count(struct net *net,
 }
 EXPORT_SYMBOL_GPL(nf_conncount_count);
 
-struct nf_conncount_data *nf_conncount_init(struct net *net, unsigned int family,
-					    unsigned int keylen)
+struct nf_conncount_data *nf_conncount_init(struct net *net, unsigned int keylen)
 {
 	struct nf_conncount_data *data;
-	int ret, i;
+	int i;
 
 	if (keylen % sizeof(u32) ||
 	    keylen / sizeof(u32) > MAX_KEYLEN ||
@@ -539,12 +538,6 @@ struct nf_conncount_data *nf_conncount_init(struct net *net, unsigned int family
 	if (!data)
 		return ERR_PTR(-ENOMEM);
 
-	ret = nf_ct_netns_get(net, family);
-	if (ret < 0) {
-		kfree(data);
-		return ERR_PTR(ret);
-	}
-
 	for (i = 0; i < ARRAY_SIZE(data->root); ++i)
 		data->root[i] = RB_ROOT;
 
@@ -581,13 +574,11 @@ static void destroy_tree(struct rb_root *r)
 	}
 }
 
-void nf_conncount_destroy(struct net *net, unsigned int family,
-			  struct nf_conncount_data *data)
+void nf_conncount_destroy(struct net *net, struct nf_conncount_data *data)
 {
 	unsigned int i;
 
 	cancel_work_sync(&data->gc_work);
-	nf_ct_netns_put(net, family);
 
 	for (i = 0; i < ARRAY_SIZE(data->root); ++i)
 		destroy_tree(&data->root[i]);

net/netfilter/xt_connlimit.c

@@ -86,6 +86,7 @@ static int connlimit_mt_check(const struct xt_mtchk_param *par)
 {
 	struct xt_connlimit_info *info = par->matchinfo;
 	unsigned int keylen;
+	int ret;
 
 	keylen = sizeof(u32);
 	if (par->family == NFPROTO_IPV6)
@@ -93,8 +94,17 @@ static int connlimit_mt_check(const struct xt_mtchk_param *par)
 	else
 		keylen += sizeof(struct in_addr);
 
+	ret = nf_ct_netns_get(par->net, par->family);
+	if (ret < 0) {
+		pr_info_ratelimited("cannot load conntrack support for proto=%u\n",
+				    par->family);
+		return ret;
+	}
+
 	/* init private data */
-	info->data = nf_conncount_init(par->net, par->family, keylen);
+	info->data = nf_conncount_init(par->net, keylen);
+	if (IS_ERR(info->data))
+		nf_ct_netns_put(par->net, par->family);
 
 	return PTR_ERR_OR_ZERO(info->data);
 }
@@ -103,7 +113,8 @@ static void connlimit_mt_destroy(const struct xt_mtdtor_param *par)
 {
 	const struct xt_connlimit_info *info = par->matchinfo;
 
-	nf_conncount_destroy(par->net, par->family, info->data);
+	nf_conncount_destroy(par->net, info->data);
+	nf_ct_netns_put(par->net, par->family);
 }
 
 static struct xt_match connlimit_mt_reg __read_mostly = {

net/openvswitch/conntrack.c

@@ -1608,8 +1608,7 @@ static int ovs_ct_limit_init(struct net *net, struct ovs_net *ovs_net)
 	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));
+	ovs_net->ct_limit_info->data = nf_conncount_init(net, sizeof(u32));
 
 	if (IS_ERR(ovs_net->ct_limit_info->data)) {
 		err = PTR_ERR(ovs_net->ct_limit_info->data);
@@ -1626,7 +1625,7 @@ 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);
+	nf_conncount_destroy(net, info->data);
 	for (i = 0; i < CT_LIMIT_HASH_BUCKETS; ++i) {
 		struct hlist_head *head = &info->limits[i];
 		struct ovs_ct_limit *ct_limit;