net/netfilter/nf_conntrack_proto.c - kernel/windcharger - Git at Google

 /* L3/L4 protocol support for nf_conntrack. */

 /* (C) 1999-2001 Paul `Rusty' Russell
  * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
  * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org>
  *
  * 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.
  */

 #include <linux/types.h>
 #include <linux/netfilter.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/mutex.h>
 #include <linux/vmalloc.h>
 #include <linux/stddef.h>
 #include <linux/err.h>
 #include <linux/percpu.h>
 #include <linux/notifier.h>
 #include <linux/kernel.h>
 #include <linux/netdevice.h>
 #include <linux/rtnetlink.h>

 #include <net/netfilter/nf_conntrack.h>
 #include <net/netfilter/nf_conntrack_l3proto.h>
 #include <net/netfilter/nf_conntrack_l4proto.h>
 #include <net/netfilter/nf_conntrack_core.h>

 static struct nf_conntrack_l4proto __rcu **nf_ct_protos[PF_MAX] __read_mostly;
 struct nf_conntrack_l3proto __rcu *nf_ct_l3protos[AF_MAX] __read_mostly;
 EXPORT_SYMBOL_GPL(nf_ct_l3protos);

 static DEFINE_MUTEX(nf_ct_proto_mutex);

 #ifdef CONFIG_SYSCTL
 static int
 nf_ct_register_sysctl(struct ctl_table_header **header, struct ctl_path *path,
 		      struct ctl_table *table, unsigned int *users)
 {
 	if (*header == NULL) {
 		*header = register_sysctl_paths(path, table);
 		if (*header == NULL)
 			return -ENOMEM;
 	}
 	if (users != NULL)
 		(*users)++;
 	return 0;
 }

 static void
 nf_ct_unregister_sysctl(struct ctl_table_header **header,
 			struct ctl_table *table, unsigned int *users)
 {
 	if (users != NULL && --*users > 0)
 		return;

 	unregister_sysctl_table(*header);
 	*header = NULL;
 }
 #endif

 struct nf_conntrack_l4proto *
 __nf_ct_l4proto_find(u_int16_t l3proto, u_int8_t l4proto)
 {
 	if (unlikely(l3proto >= AF_MAX || nf_ct_protos[l3proto] == NULL))
 		return &nf_conntrack_l4proto_generic;

 	return rcu_dereference(nf_ct_protos[l3proto][l4proto]);
 }
 EXPORT_SYMBOL_GPL(__nf_ct_l4proto_find);

 /* this is guaranteed to always return a valid protocol helper, since
  * it falls back to generic_protocol */
 struct nf_conntrack_l3proto *
 nf_ct_l3proto_find_get(u_int16_t l3proto)
 {
 	struct nf_conntrack_l3proto *p;

 	rcu_read_lock();
 	p = __nf_ct_l3proto_find(l3proto);
 	if (!try_module_get(p->me))
 		p = &nf_conntrack_l3proto_generic;
 	rcu_read_unlock();

 	return p;
 }
 EXPORT_SYMBOL_GPL(nf_ct_l3proto_find_get);

 void nf_ct_l3proto_put(struct nf_conntrack_l3proto *p)
 {
 	module_put(p->me);
 }
 EXPORT_SYMBOL_GPL(nf_ct_l3proto_put);

 int
 nf_ct_l3proto_try_module_get(unsigned short l3proto)
 {
 	int ret;
 	struct nf_conntrack_l3proto *p;

 retry:	p = nf_ct_l3proto_find_get(l3proto);
 	if (p == &nf_conntrack_l3proto_generic) {
 		ret = request_module("nf_conntrack-%d", l3proto);
 		if (!ret)
 			goto retry;

 		return -EPROTOTYPE;
 	}

 	return 0;
 }
 EXPORT_SYMBOL_GPL(nf_ct_l3proto_try_module_get);

 void nf_ct_l3proto_module_put(unsigned short l3proto)
 {
 	struct nf_conntrack_l3proto *p;

 	/* rcu_read_lock not necessary since the caller holds a reference, but
 	 * taken anyways to avoid lockdep warnings in __nf_ct_l3proto_find()
 	 */
 	rcu_read_lock();
 	p = __nf_ct_l3proto_find(l3proto);
 	module_put(p->me);
 	rcu_read_unlock();
 }
 EXPORT_SYMBOL_GPL(nf_ct_l3proto_module_put);

 static int kill_l3proto(struct nf_conn *i, void *data)
 {
 	return nf_ct_l3num(i) == ((struct nf_conntrack_l3proto *)data)->l3proto;
 }

 static int kill_l4proto(struct nf_conn *i, void *data)
 {
 	struct nf_conntrack_l4proto *l4proto;
 	l4proto = (struct nf_conntrack_l4proto *)data;
 	return nf_ct_protonum(i) == l4proto->l4proto &&
 	       nf_ct_l3num(i) == l4proto->l3proto;
 }

 static int nf_ct_l3proto_register_sysctl(struct nf_conntrack_l3proto *l3proto)
 {
 	int err = 0;

 #ifdef CONFIG_SYSCTL
 	if (l3proto->ctl_table != NULL) {
 		err = nf_ct_register_sysctl(&l3proto->ctl_table_header,
 					    l3proto->ctl_table_path,
 					    l3proto->ctl_table, NULL);
 	}
 #endif
 	return err;
 }

 static void nf_ct_l3proto_unregister_sysctl(struct nf_conntrack_l3proto *l3proto)
 {
 #ifdef CONFIG_SYSCTL
 	if (l3proto->ctl_table_header != NULL)
 		nf_ct_unregister_sysctl(&l3proto->ctl_table_header,
 					l3proto->ctl_table, NULL);
 #endif
 }

 int nf_conntrack_l3proto_register(struct nf_conntrack_l3proto *proto)
 {
 	int ret = 0;
 	struct nf_conntrack_l3proto *old;

 	if (proto->l3proto >= AF_MAX)
 		return -EBUSY;

 	if (proto->tuple_to_nlattr && !proto->nlattr_tuple_size)
 		return -EINVAL;

 	mutex_lock(&nf_ct_proto_mutex);
 	old = rcu_dereference_protected(nf_ct_l3protos[proto->l3proto],
 					lockdep_is_held(&nf_ct_proto_mutex));
 	if (old != &nf_conntrack_l3proto_generic) {
 		ret = -EBUSY;
 		goto out_unlock;
 	}

 	ret = nf_ct_l3proto_register_sysctl(proto);
 	if (ret < 0)
 		goto out_unlock;

 	if (proto->nlattr_tuple_size)
 		proto->nla_size = 3 * proto->nlattr_tuple_size();

 	rcu_assign_pointer(nf_ct_l3protos[proto->l3proto], proto);

 out_unlock:
 	mutex_unlock(&nf_ct_proto_mutex);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(nf_conntrack_l3proto_register);

 void nf_conntrack_l3proto_unregister(struct nf_conntrack_l3proto *proto)
 {
 	struct net *net;

 	BUG_ON(proto->l3proto >= AF_MAX);

 	mutex_lock(&nf_ct_proto_mutex);
 	BUG_ON(rcu_dereference_protected(nf_ct_l3protos[proto->l3proto],
 					 lockdep_is_held(&nf_ct_proto_mutex)
 					 ) != proto);
 	rcu_assign_pointer(nf_ct_l3protos[proto->l3proto],
 			   &nf_conntrack_l3proto_generic);
 	nf_ct_l3proto_unregister_sysctl(proto);
 	mutex_unlock(&nf_ct_proto_mutex);

 	synchronize_rcu();

 	/* Remove all contrack entries for this protocol */
 	rtnl_lock();
 	for_each_net(net)
 		nf_ct_iterate_cleanup(net, kill_l3proto, proto);
 	rtnl_unlock();
 }
 EXPORT_SYMBOL_GPL(nf_conntrack_l3proto_unregister);

 static int nf_ct_l4proto_register_sysctl(struct nf_conntrack_l4proto *l4proto)
 {
 	int err = 0;

 #ifdef CONFIG_SYSCTL
 	if (l4proto->ctl_table != NULL) {
 		err = nf_ct_register_sysctl(l4proto->ctl_table_header,
 					    nf_net_netfilter_sysctl_path,
 					    l4proto->ctl_table,
 					    l4proto->ctl_table_users);
 		if (err < 0)
 			goto out;
 	}
 #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
 	if (l4proto->ctl_compat_table != NULL) {
 		err = nf_ct_register_sysctl(&l4proto->ctl_compat_table_header,
 					    nf_net_ipv4_netfilter_sysctl_path,
 					    l4proto->ctl_compat_table, NULL);
 		if (err == 0)
 			goto out;
 		nf_ct_unregister_sysctl(l4proto->ctl_table_header,
 					l4proto->ctl_table,
 					l4proto->ctl_table_users);
 	}
 #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
 out:
 #endif /* CONFIG_SYSCTL */
 	return err;
 }

 static void nf_ct_l4proto_unregister_sysctl(struct nf_conntrack_l4proto *l4proto)
 {
 #ifdef CONFIG_SYSCTL
 	if (l4proto->ctl_table_header != NULL &&
 	    *l4proto->ctl_table_header != NULL)
 		nf_ct_unregister_sysctl(l4proto->ctl_table_header,
 					l4proto->ctl_table,
 					l4proto->ctl_table_users);
 #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
 	if (l4proto->ctl_compat_table_header != NULL)
 		nf_ct_unregister_sysctl(&l4proto->ctl_compat_table_header,
 					l4proto->ctl_compat_table, NULL);
 #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
 #endif /* CONFIG_SYSCTL */
 }

 /* FIXME: Allow NULL functions and sub in pointers to generic for
    them. --RR */
 int nf_conntrack_l4proto_register(struct nf_conntrack_l4proto *l4proto)
 {
 	int ret = 0;

 	if (l4proto->l3proto >= PF_MAX)
 		return -EBUSY;

 	if ((l4proto->to_nlattr && !l4proto->nlattr_size)
 		|| (l4proto->tuple_to_nlattr && !l4proto->nlattr_tuple_size))
 		return -EINVAL;

 	mutex_lock(&nf_ct_proto_mutex);
 	if (!nf_ct_protos[l4proto->l3proto]) {
 		/* l3proto may be loaded latter. */
 		struct nf_conntrack_l4proto __rcu **proto_array;
 		int i;

 		proto_array = kmalloc(MAX_NF_CT_PROTO *
 				      sizeof(struct nf_conntrack_l4proto *),
 				      GFP_KERNEL);
 		if (proto_array == NULL) {
 			ret = -ENOMEM;
 			goto out_unlock;
 		}

 		for (i = 0; i < MAX_NF_CT_PROTO; i++)
 			RCU_INIT_POINTER(proto_array[i], &nf_conntrack_l4proto_generic);

 		/* Before making proto_array visible to lockless readers,
 		 * we must make sure its content is committed to memory.
 		 */
 		smp_wmb();

 		nf_ct_protos[l4proto->l3proto] = proto_array;
 	} else if (rcu_dereference_protected(
 			nf_ct_protos[l4proto->l3proto][l4proto->l4proto],
 			lockdep_is_held(&nf_ct_proto_mutex)
 			) != &nf_conntrack_l4proto_generic) {
 		ret = -EBUSY;
 		goto out_unlock;
 	}

 	ret = nf_ct_l4proto_register_sysctl(l4proto);
 	if (ret < 0)
 		goto out_unlock;

 	l4proto->nla_size = 0;
 	if (l4proto->nlattr_size)
 		l4proto->nla_size += l4proto->nlattr_size();
 	if (l4proto->nlattr_tuple_size)
 		l4proto->nla_size += 3 * l4proto->nlattr_tuple_size();

 	rcu_assign_pointer(nf_ct_protos[l4proto->l3proto][l4proto->l4proto],
 			   l4proto);

 out_unlock:
 	mutex_unlock(&nf_ct_proto_mutex);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_register);

 void nf_conntrack_l4proto_unregister(struct nf_conntrack_l4proto *l4proto)
 {
 	struct net *net;

 	BUG_ON(l4proto->l3proto >= PF_MAX);

 	mutex_lock(&nf_ct_proto_mutex);
 	BUG_ON(rcu_dereference_protected(
 			nf_ct_protos[l4proto->l3proto][l4proto->l4proto],
 			lockdep_is_held(&nf_ct_proto_mutex)
 			) != l4proto);
 	rcu_assign_pointer(nf_ct_protos[l4proto->l3proto][l4proto->l4proto],
 			   &nf_conntrack_l4proto_generic);
 	nf_ct_l4proto_unregister_sysctl(l4proto);
 	mutex_unlock(&nf_ct_proto_mutex);

 	synchronize_rcu();

 	/* Remove all contrack entries for this protocol */
 	rtnl_lock();
 	for_each_net(net)
 		nf_ct_iterate_cleanup(net, kill_l4proto, l4proto);
 	rtnl_unlock();
 }
 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_unregister);

 int nf_conntrack_proto_init(void)
 {
 	unsigned int i;
 	int err;

 	err = nf_ct_l4proto_register_sysctl(&nf_conntrack_l4proto_generic);
 	if (err < 0)
 		return err;

 	for (i = 0; i < AF_MAX; i++)
 		rcu_assign_pointer(nf_ct_l3protos[i],
 				   &nf_conntrack_l3proto_generic);
 	return 0;
 }

 void nf_conntrack_proto_fini(void)
 {
 	unsigned int i;

 	nf_ct_l4proto_unregister_sysctl(&nf_conntrack_l4proto_generic);

 	/* free l3proto protocol tables */
 	for (i = 0; i < PF_MAX; i++)
 		kfree(nf_ct_protos[i]);
 }
	/* L3/L4 protocol support for nf_conntrack. */

	/* (C) 1999-2001 Paul `Rusty' Russell
	* (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
	* (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org>
	*
	* 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.
	*/

	#include <linux/types.h>
	#include <linux/netfilter.h>
	#include <linux/module.h>
	#include <linux/slab.h>
	#include <linux/mutex.h>
	#include <linux/vmalloc.h>
	#include <linux/stddef.h>
	#include <linux/err.h>
	#include <linux/percpu.h>
	#include <linux/notifier.h>
	#include <linux/kernel.h>
	#include <linux/netdevice.h>
	#include <linux/rtnetlink.h>

	#include <net/netfilter/nf_conntrack.h>
	#include <net/netfilter/nf_conntrack_l3proto.h>
	#include <net/netfilter/nf_conntrack_l4proto.h>
	#include <net/netfilter/nf_conntrack_core.h>

	static struct nf_conntrack_l4proto __rcu **nf_ct_protos[PF_MAX] __read_mostly;
	struct nf_conntrack_l3proto __rcu *nf_ct_l3protos[AF_MAX] __read_mostly;
	EXPORT_SYMBOL_GPL(nf_ct_l3protos);

	static DEFINE_MUTEX(nf_ct_proto_mutex);

	#ifdef CONFIG_SYSCTL
	static int
	nf_ct_register_sysctl(struct ctl_table_header *header, struct ctl_path path,
	struct ctl_table table, unsigned int users)
	{
	if (*header == NULL) {
	*header = register_sysctl_paths(path, table);
	if (*header == NULL)
	return -ENOMEM;
	}
	if (users != NULL)
	(*users)++;
	return 0;
	}

	static void
	nf_ct_unregister_sysctl(struct ctl_table_header **header,
	struct ctl_table table, unsigned int users)
	{
	if (users != NULL && --*users > 0)
	return;

	unregister_sysctl_table(*header);
	*header = NULL;
	}
	#endif

	struct nf_conntrack_l4proto *
	__nf_ct_l4proto_find(u_int16_t l3proto, u_int8_t l4proto)
	{
	if (unlikely(l3proto >= AF_MAX \|\| nf_ct_protos[l3proto] == NULL))
	return &nf_conntrack_l4proto_generic;

	return rcu_dereference(nf_ct_protos[l3proto][l4proto]);
	}
	EXPORT_SYMBOL_GPL(__nf_ct_l4proto_find);

	/* this is guaranteed to always return a valid protocol helper, since
	* it falls back to generic_protocol */
	struct nf_conntrack_l3proto *
	nf_ct_l3proto_find_get(u_int16_t l3proto)
	{
	struct nf_conntrack_l3proto *p;

	rcu_read_lock();
	p = __nf_ct_l3proto_find(l3proto);
	if (!try_module_get(p->me))
	p = &nf_conntrack_l3proto_generic;
	rcu_read_unlock();

	return p;
	}
	EXPORT_SYMBOL_GPL(nf_ct_l3proto_find_get);

	void nf_ct_l3proto_put(struct nf_conntrack_l3proto *p)
	{
	module_put(p->me);
	}
	EXPORT_SYMBOL_GPL(nf_ct_l3proto_put);

	int
	nf_ct_l3proto_try_module_get(unsigned short l3proto)
	{
	int ret;
	struct nf_conntrack_l3proto *p;

	retry: p = nf_ct_l3proto_find_get(l3proto);
	if (p == &nf_conntrack_l3proto_generic) {
	ret = request_module("nf_conntrack-%d", l3proto);
	if (!ret)
	goto retry;

	return -EPROTOTYPE;
	}

	return 0;
	}
	EXPORT_SYMBOL_GPL(nf_ct_l3proto_try_module_get);

	void nf_ct_l3proto_module_put(unsigned short l3proto)
	{
	struct nf_conntrack_l3proto *p;

	/* rcu_read_lock not necessary since the caller holds a reference, but
	* taken anyways to avoid lockdep warnings in __nf_ct_l3proto_find()
	*/
	rcu_read_lock();
	p = __nf_ct_l3proto_find(l3proto);
	module_put(p->me);
	rcu_read_unlock();
	}
	EXPORT_SYMBOL_GPL(nf_ct_l3proto_module_put);

	static int kill_l3proto(struct nf_conn i, void data)
	{
	return nf_ct_l3num(i) == ((struct nf_conntrack_l3proto *)data)->l3proto;
	}

	static int kill_l4proto(struct nf_conn i, void data)
	{
	struct nf_conntrack_l4proto *l4proto;
	l4proto = (struct nf_conntrack_l4proto *)data;
	return nf_ct_protonum(i) == l4proto->l4proto &&
	nf_ct_l3num(i) == l4proto->l3proto;
	}

	static int nf_ct_l3proto_register_sysctl(struct nf_conntrack_l3proto *l3proto)
	{
	int err = 0;

	#ifdef CONFIG_SYSCTL
	if (l3proto->ctl_table != NULL) {
	err = nf_ct_register_sysctl(&l3proto->ctl_table_header,
	l3proto->ctl_table_path,
	l3proto->ctl_table, NULL);
	}
	#endif
	return err;
	}

	static void nf_ct_l3proto_unregister_sysctl(struct nf_conntrack_l3proto *l3proto)
	{
	#ifdef CONFIG_SYSCTL
	if (l3proto->ctl_table_header != NULL)
	nf_ct_unregister_sysctl(&l3proto->ctl_table_header,
	l3proto->ctl_table, NULL);
	#endif
	}

	int nf_conntrack_l3proto_register(struct nf_conntrack_l3proto *proto)
	{
	int ret = 0;
	struct nf_conntrack_l3proto *old;

	if (proto->l3proto >= AF_MAX)
	return -EBUSY;

	if (proto->tuple_to_nlattr && !proto->nlattr_tuple_size)
	return -EINVAL;

	mutex_lock(&nf_ct_proto_mutex);
	old = rcu_dereference_protected(nf_ct_l3protos[proto->l3proto],
	lockdep_is_held(&nf_ct_proto_mutex));
	if (old != &nf_conntrack_l3proto_generic) {
	ret = -EBUSY;
	goto out_unlock;
	}

	ret = nf_ct_l3proto_register_sysctl(proto);
	if (ret < 0)
	goto out_unlock;

	if (proto->nlattr_tuple_size)
	proto->nla_size = 3 * proto->nlattr_tuple_size();

	rcu_assign_pointer(nf_ct_l3protos[proto->l3proto], proto);

	out_unlock:
	mutex_unlock(&nf_ct_proto_mutex);
	return ret;
	}
	EXPORT_SYMBOL_GPL(nf_conntrack_l3proto_register);

	void nf_conntrack_l3proto_unregister(struct nf_conntrack_l3proto *proto)
	{
	struct net *net;

	BUG_ON(proto->l3proto >= AF_MAX);

	mutex_lock(&nf_ct_proto_mutex);
	BUG_ON(rcu_dereference_protected(nf_ct_l3protos[proto->l3proto],
	lockdep_is_held(&nf_ct_proto_mutex)
	) != proto);
	rcu_assign_pointer(nf_ct_l3protos[proto->l3proto],
	&nf_conntrack_l3proto_generic);
	nf_ct_l3proto_unregister_sysctl(proto);
	mutex_unlock(&nf_ct_proto_mutex);

	synchronize_rcu();

	/* Remove all contrack entries for this protocol */
	rtnl_lock();
	for_each_net(net)
	nf_ct_iterate_cleanup(net, kill_l3proto, proto);
	rtnl_unlock();
	}
	EXPORT_SYMBOL_GPL(nf_conntrack_l3proto_unregister);

	static int nf_ct_l4proto_register_sysctl(struct nf_conntrack_l4proto *l4proto)
	{
	int err = 0;

	#ifdef CONFIG_SYSCTL
	if (l4proto->ctl_table != NULL) {
	err = nf_ct_register_sysctl(l4proto->ctl_table_header,
	nf_net_netfilter_sysctl_path,
	l4proto->ctl_table,
	l4proto->ctl_table_users);
	if (err < 0)
	goto out;
	}
	#ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
	if (l4proto->ctl_compat_table != NULL) {
	err = nf_ct_register_sysctl(&l4proto->ctl_compat_table_header,
	nf_net_ipv4_netfilter_sysctl_path,
	l4proto->ctl_compat_table, NULL);
	if (err == 0)
	goto out;
	nf_ct_unregister_sysctl(l4proto->ctl_table_header,
	l4proto->ctl_table,
	l4proto->ctl_table_users);
	}
	#endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
	out:
	#endif /* CONFIG_SYSCTL */
	return err;
	}

	static void nf_ct_l4proto_unregister_sysctl(struct nf_conntrack_l4proto *l4proto)
	{
	#ifdef CONFIG_SYSCTL
	if (l4proto->ctl_table_header != NULL &&
	*l4proto->ctl_table_header != NULL)
	nf_ct_unregister_sysctl(l4proto->ctl_table_header,
	l4proto->ctl_table,
	l4proto->ctl_table_users);
	#ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
	if (l4proto->ctl_compat_table_header != NULL)
	nf_ct_unregister_sysctl(&l4proto->ctl_compat_table_header,
	l4proto->ctl_compat_table, NULL);
	#endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
	#endif /* CONFIG_SYSCTL */
	}

	/* FIXME: Allow NULL functions and sub in pointers to generic for
	them. --RR */
	int nf_conntrack_l4proto_register(struct nf_conntrack_l4proto *l4proto)
	{
	int ret = 0;

	if (l4proto->l3proto >= PF_MAX)
	return -EBUSY;

	if ((l4proto->to_nlattr && !l4proto->nlattr_size)
	\|\| (l4proto->tuple_to_nlattr && !l4proto->nlattr_tuple_size))
	return -EINVAL;

	mutex_lock(&nf_ct_proto_mutex);
	if (!nf_ct_protos[l4proto->l3proto]) {
	/* l3proto may be loaded latter. */
	struct nf_conntrack_l4proto __rcu **proto_array;
	int i;

	proto_array = kmalloc(MAX_NF_CT_PROTO *
	sizeof(struct nf_conntrack_l4proto *),
	GFP_KERNEL);
	if (proto_array == NULL) {
	ret = -ENOMEM;
	goto out_unlock;
	}

	for (i = 0; i < MAX_NF_CT_PROTO; i++)
	RCU_INIT_POINTER(proto_array[i], &nf_conntrack_l4proto_generic);

	/* Before making proto_array visible to lockless readers,
	* we must make sure its content is committed to memory.
	*/
	smp_wmb();

	nf_ct_protos[l4proto->l3proto] = proto_array;
	} else if (rcu_dereference_protected(
	nf_ct_protos[l4proto->l3proto][l4proto->l4proto],
	lockdep_is_held(&nf_ct_proto_mutex)
	) != &nf_conntrack_l4proto_generic) {
	ret = -EBUSY;
	goto out_unlock;
	}

	ret = nf_ct_l4proto_register_sysctl(l4proto);
	if (ret < 0)
	goto out_unlock;

	l4proto->nla_size = 0;
	if (l4proto->nlattr_size)
	l4proto->nla_size += l4proto->nlattr_size();
	if (l4proto->nlattr_tuple_size)
	l4proto->nla_size += 3 * l4proto->nlattr_tuple_size();

	rcu_assign_pointer(nf_ct_protos[l4proto->l3proto][l4proto->l4proto],
	l4proto);

	out_unlock:
	mutex_unlock(&nf_ct_proto_mutex);
	return ret;
	}
	EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_register);

	void nf_conntrack_l4proto_unregister(struct nf_conntrack_l4proto *l4proto)
	{
	struct net *net;

	BUG_ON(l4proto->l3proto >= PF_MAX);

	mutex_lock(&nf_ct_proto_mutex);
	BUG_ON(rcu_dereference_protected(
	nf_ct_protos[l4proto->l3proto][l4proto->l4proto],
	lockdep_is_held(&nf_ct_proto_mutex)
	) != l4proto);
	rcu_assign_pointer(nf_ct_protos[l4proto->l3proto][l4proto->l4proto],
	&nf_conntrack_l4proto_generic);
	nf_ct_l4proto_unregister_sysctl(l4proto);
	mutex_unlock(&nf_ct_proto_mutex);

	synchronize_rcu();

	/* Remove all contrack entries for this protocol */
	rtnl_lock();
	for_each_net(net)
	nf_ct_iterate_cleanup(net, kill_l4proto, l4proto);
	rtnl_unlock();
	}
	EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_unregister);

	int nf_conntrack_proto_init(void)
	{
	unsigned int i;
	int err;

	err = nf_ct_l4proto_register_sysctl(&nf_conntrack_l4proto_generic);
	if (err < 0)
	return err;

	for (i = 0; i < AF_MAX; i++)
	rcu_assign_pointer(nf_ct_l3protos[i],
	&nf_conntrack_l3proto_generic);
	return 0;
	}

	void nf_conntrack_proto_fini(void)
	{
	unsigned int i;

	nf_ct_l4proto_unregister_sysctl(&nf_conntrack_l4proto_generic);

	/* free l3proto protocol tables */
	for (i = 0; i < PF_MAX; i++)
	kfree(nf_ct_protos[i]);
	}