netfilter: Export nf_ct_{set,destroy}_timeout()

This patch exports nf_ct_set_timeout() and nf_ct_destroy_timeout().
The two functions are derived from xt_ct_destroy_timeout() and
xt_ct_set_timeout() in xt_CT.c, and moved to nf_conntrack_timeout.c
without any functional change.
It would be useful for other users (i.e. OVS) that utilizes the
finer-grain conntrack timeout feature.

CC: Pablo Neira Ayuso <pablo@netfilter.org>
CC: Pravin Shelar <pshelar@ovn.org>
Signed-off-by: Yi-Hung Wei <yihung.wei@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 89 insertions, 0 deletions

diff --git a/net/netfilter/nf_conntrack_timeout.c b/net/netfilter/nf_conntrack_timeout.c
index 91fbd183da2d..edac8ea4436d 100644
--- a/net/netfilter/nf_conntrack_timeout.c
+++ b/net/netfilter/nf_conntrack_timeout.c
@@ -48,6 +48,95 @@ void nf_ct_untimeout(struct net *net, struct nf_ct_timeout *timeout)
 }
 EXPORT_SYMBOL_GPL(nf_ct_untimeout);
 
+static void __nf_ct_timeout_put(struct nf_ct_timeout *timeout)
+{
+	typeof(nf_ct_timeout_put_hook) timeout_put;
+
+	timeout_put = rcu_dereference(nf_ct_timeout_put_hook);
+	if (timeout_put)
+		timeout_put(timeout);
+}
+
+int nf_ct_set_timeout(struct net *net, struct nf_conn *ct,
+		      u8 l3num, u8 l4num, const char *timeout_name)
+{
+	typeof(nf_ct_timeout_find_get_hook) timeout_find_get;
+	struct nf_ct_timeout *timeout;
+	struct nf_conn_timeout *timeout_ext;
+	const char *errmsg = NULL;
+	int ret = 0;
+
+	rcu_read_lock();
+	timeout_find_get = rcu_dereference(nf_ct_timeout_find_get_hook);
+	if (!timeout_find_get) {
+		ret = -ENOENT;
+		errmsg = "Timeout policy base is empty";
+		goto out;
+	}
+
+	timeout = timeout_find_get(net, timeout_name);
+	if (!timeout) {
+		ret = -ENOENT;
+		pr_info_ratelimited("No such timeout policy \"%s\"\n",
+				    timeout_name);
+		goto out;
+	}
+
+	if (timeout->l3num != l3num) {
+		ret = -EINVAL;
+		pr_info_ratelimited("Timeout policy `%s' can only be used by "
+				    "L%d protocol number %d\n",
+				    timeout_name, 3, timeout->l3num);
+		goto err_put_timeout;
+	}
+	/* Make sure the timeout policy matches any existing protocol tracker,
+	 * otherwise default to generic.
+	 */
+	if (timeout->l4proto->l4proto != l4num) {
+		ret = -EINVAL;
+		pr_info_ratelimited("Timeout policy `%s' can only be used by "
+				    "L%d protocol number %d\n",
+				    timeout_name, 4, timeout->l4proto->l4proto);
+		goto err_put_timeout;
+	}
+	timeout_ext = nf_ct_timeout_ext_add(ct, timeout, GFP_ATOMIC);
+	if (!timeout_ext) {
+		ret = -ENOMEM;
+		goto err_put_timeout;
+	}
+
+	rcu_read_unlock();
+	return ret;
+
+err_put_timeout:
+	__nf_ct_timeout_put(timeout);
+out:
+	rcu_read_unlock();
+	if (errmsg)
+		pr_info_ratelimited("%s\n", errmsg);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(nf_ct_set_timeout);
+
+void nf_ct_destroy_timeout(struct nf_conn *ct)
+{
+	struct nf_conn_timeout *timeout_ext;
+	typeof(nf_ct_timeout_put_hook) timeout_put;
+
+	rcu_read_lock();
+	timeout_put = rcu_dereference(nf_ct_timeout_put_hook);
+
+	if (timeout_put) {
+		timeout_ext = nf_ct_timeout_find(ct);
+		if (timeout_ext) {
+			timeout_put(timeout_ext->timeout);
+			RCU_INIT_POINTER(timeout_ext->timeout, NULL);
+		}
+	}
+	rcu_read_unlock();
+}
+EXPORT_SYMBOL_GPL(nf_ct_destroy_timeout);
+
 static const struct nf_ct_ext_type timeout_extend = {
 	.len	= sizeof(struct nf_conn_timeout),
 	.align	= __alignof__(struct nf_conn_timeout),