netfilter: nf_ct_ext: add timeout extension

This patch adds the timeout extension, which allows you to attach
specific timeout policies to flows.

This extension is only used by the template conntrack.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
diff --git a/net/netfilter/nf_conntrack_timeout.c b/net/netfilter/nf_conntrack_timeout.c
new file mode 100644
index 0000000..a878ce5
--- /dev/null
+++ b/net/netfilter/nf_conntrack_timeout.c
@@ -0,0 +1,60 @@
+/*
+ * (C) 2012 by Pablo Neira Ayuso <pablo@netfilter.org>
+ * (C) 2012 by Vyatta Inc. <http://www.vyatta.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation (or any later at your option).
+ */
+
+#include <linux/types.h>
+#include <linux/netfilter.h>
+#include <linux/skbuff.h>
+#include <linux/vmalloc.h>
+#include <linux/stddef.h>
+#include <linux/err.h>
+#include <linux/percpu.h>
+#include <linux/kernel.h>
+#include <linux/netdevice.h>
+#include <linux/slab.h>
+#include <linux/export.h>
+
+#include <net/netfilter/nf_conntrack.h>
+#include <net/netfilter/nf_conntrack_core.h>
+#include <net/netfilter/nf_conntrack_extend.h>
+#include <net/netfilter/nf_conntrack_timeout.h>
+
+struct ctnl_timeout *
+(*nf_ct_timeout_find_get_hook)(const char *name) __read_mostly;
+EXPORT_SYMBOL_GPL(nf_ct_timeout_find_get_hook);
+
+void (*nf_ct_timeout_put_hook)(struct ctnl_timeout *timeout) __read_mostly;
+EXPORT_SYMBOL_GPL(nf_ct_timeout_put_hook);
+
+static struct nf_ct_ext_type timeout_extend __read_mostly = {
+	.len	= sizeof(struct nf_conn_timeout),
+	.align	= __alignof__(struct nf_conn_timeout),
+	.id	= NF_CT_EXT_TIMEOUT,
+};
+
+int nf_conntrack_timeout_init(struct net *net)
+{
+	int ret = 0;
+
+	if (net_eq(net, &init_net)) {
+		ret = nf_ct_extend_register(&timeout_extend);
+		if (ret < 0) {
+			printk(KERN_ERR "nf_ct_timeout: Unable to register "
+					"timeout extension.\n");
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+void nf_conntrack_timeout_fini(struct net *net)
+{
+	if (net_eq(net, &init_net))
+		nf_ct_extend_unregister(&timeout_extend);
+}