net/netfilter/nf_conntrack_proto.c - linux/kernel/git/mellanox/linux - 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/mutex.h>
 #include <linux/skbuff.h>
 #include <linux/vmalloc.h>
 #include <linux/stddef.h>
 #include <linux/err.h>
 #include <linux/percpu.h>
 #include <linux/moduleparam.h>
 #include <linux/notifier.h>
 #include <linux/kernel.h>
 #include <linux/netdevice.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>

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

 #ifdef CONFIG_SYSCTL
 static DEFINE_MUTEX(nf_ct_proto_sysctl_mutex);

 static int
 nf_ct_register_sysctl(struct ctl_table_header **header, struct ctl_table *path,
 		      struct ctl_table *table, unsigned int *users)
 {
 	if (*header == NULL) {
 		*header = nf_register_sysctl_table(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;
 	nf_unregister_sysctl_table(*header, table);
 	*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_l4proto *
 nf_ct_l4proto_find_get(u_int16_t l3proto, u_int8_t l4proto)
 {
 	struct nf_conntrack_l4proto *p;

 	rcu_read_lock();
 	p = __nf_ct_l4proto_find(l3proto, l4proto);
 	if (!try_module_get(p->me))
 		p = &nf_conntrack_l4proto_generic;
 	rcu_read_unlock();

 	return p;
 }
 EXPORT_SYMBOL_GPL(nf_ct_l4proto_find_get);

 void nf_ct_l4proto_put(struct nf_conntrack_l4proto *p)
 {
 	module_put(p->me);
 }
 EXPORT_SYMBOL_GPL(nf_ct_l4proto_put);

 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 */
 	p = __nf_ct_l3proto_find(l3proto);
 	module_put(p->me);
 }
 EXPORT_SYMBOL_GPL(nf_ct_l3proto_module_put);

 static int kill_l3proto(struct nf_conn *i, void *data)
 {
 	return (i->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num ==
 			((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 (i->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum ==
 			l4proto->l4proto) &&
 	       (i->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num ==
 			l4proto->l3proto);
 }

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

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

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

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

 	if (proto->l3proto >= AF_MAX) {
 		ret = -EBUSY;
 		goto out;
 	}

 	write_lock_bh(&nf_conntrack_lock);
 	if (nf_ct_l3protos[proto->l3proto] != &nf_conntrack_l3proto_generic) {
 		ret = -EBUSY;
 		goto out_unlock;
 	}
 	rcu_assign_pointer(nf_ct_l3protos[proto->l3proto], proto);
 	write_unlock_bh(&nf_conntrack_lock);

 	ret = nf_ct_l3proto_register_sysctl(proto);
 	if (ret < 0)
 		nf_conntrack_l3proto_unregister(proto);
 	return ret;

 out_unlock:
 	write_unlock_bh(&nf_conntrack_lock);
 out:
 	return ret;
 }
 EXPORT_SYMBOL_GPL(nf_conntrack_l3proto_register);

 void nf_conntrack_l3proto_unregister(struct nf_conntrack_l3proto *proto)
 {
 	BUG_ON(proto->l3proto >= AF_MAX);

 	write_lock_bh(&nf_conntrack_lock);
 	BUG_ON(nf_ct_l3protos[proto->l3proto] != proto);
 	rcu_assign_pointer(nf_ct_l3protos[proto->l3proto],
 			   &nf_conntrack_l3proto_generic);
 	write_unlock_bh(&nf_conntrack_lock);
 	synchronize_rcu();

 	nf_ct_l3proto_unregister_sysctl(proto);

 	/* Remove all contrack entries for this protocol */
 	nf_ct_iterate_cleanup(kill_l3proto, proto);
 }
 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
 	mutex_lock(&nf_ct_proto_sysctl_mutex);
 	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:
 	mutex_unlock(&nf_ct_proto_sysctl_mutex);
 #endif /* CONFIG_SYSCTL */
 	return err;
 }

 static void nf_ct_l4proto_unregister_sysctl(struct nf_conntrack_l4proto *l4proto)
 {
 #ifdef CONFIG_SYSCTL
 	mutex_lock(&nf_ct_proto_sysctl_mutex);
 	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 */
 	mutex_unlock(&nf_ct_proto_sysctl_mutex);
 #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) {
 		ret = -EBUSY;
 		goto out;
 	}

 	if (l4proto == &nf_conntrack_l4proto_generic)
 		return nf_ct_l4proto_register_sysctl(l4proto);

 retry:
 	write_lock_bh(&nf_conntrack_lock);
 	if (nf_ct_protos[l4proto->l3proto]) {
 		if (nf_ct_protos[l4proto->l3proto][l4proto->l4proto]
 				!= &nf_conntrack_l4proto_generic) {
 			ret = -EBUSY;
 			goto out_unlock;
 		}
 	} else {
 		/* l3proto may be loaded latter. */
 		struct nf_conntrack_l4proto **proto_array;
 		int i;

 		write_unlock_bh(&nf_conntrack_lock);

 		proto_array = (struct nf_conntrack_l4proto **)
 				kmalloc(MAX_NF_CT_PROTO *
 					 sizeof(struct nf_conntrack_l4proto *),
 					GFP_KERNEL);
 		if (proto_array == NULL) {
 			ret = -ENOMEM;
 			goto out;
 		}
 		for (i = 0; i < MAX_NF_CT_PROTO; i++)
 			proto_array[i] = &nf_conntrack_l4proto_generic;

 		write_lock_bh(&nf_conntrack_lock);
 		if (nf_ct_protos[l4proto->l3proto]) {
 			/* bad timing, but no problem */
 			write_unlock_bh(&nf_conntrack_lock);
 			kfree(proto_array);
 		} else {
 			nf_ct_protos[l4proto->l3proto] = proto_array;
 			write_unlock_bh(&nf_conntrack_lock);
 		}

 		/*
 		 * Just once because array is never freed until unloading
 		 * nf_conntrack.ko
 		 */
 		goto retry;
 	}

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

 	ret = nf_ct_l4proto_register_sysctl(l4proto);
 	if (ret < 0)
 		nf_conntrack_l4proto_unregister(l4proto);
 	return ret;

 out_unlock:
 	write_unlock_bh(&nf_conntrack_lock);
 out:
 	return ret;
 }
 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_register);

 void nf_conntrack_l4proto_unregister(struct nf_conntrack_l4proto *l4proto)
 {
 	BUG_ON(l4proto->l3proto >= PF_MAX);

 	if (l4proto == &nf_conntrack_l4proto_generic) {
 		nf_ct_l4proto_unregister_sysctl(l4proto);
 		return;
 	}

 	write_lock_bh(&nf_conntrack_lock);
 	BUG_ON(nf_ct_protos[l4proto->l3proto][l4proto->l4proto] != l4proto);
 	rcu_assign_pointer(nf_ct_protos[l4proto->l3proto][l4proto->l4proto],
 			   &nf_conntrack_l4proto_generic);
 	write_unlock_bh(&nf_conntrack_lock);
 	synchronize_rcu();

 	nf_ct_l4proto_unregister_sysctl(l4proto);

 	/* Remove all contrack entries for this protocol */
 	nf_ct_iterate_cleanup(kill_l4proto, l4proto);
 }
 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_unregister);
	/* 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/mutex.h>
	#include <linux/skbuff.h>
	#include <linux/vmalloc.h>
	#include <linux/stddef.h>
	#include <linux/err.h>
	#include <linux/percpu.h>
	#include <linux/moduleparam.h>
	#include <linux/notifier.h>
	#include <linux/kernel.h>
	#include <linux/netdevice.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>

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

	#ifdef CONFIG_SYSCTL
	static DEFINE_MUTEX(nf_ct_proto_sysctl_mutex);

	static int
	nf_ct_register_sysctl(struct ctl_table_header *header, struct ctl_table path,
	struct ctl_table table, unsigned int users)
	{
	if (*header == NULL) {
	*header = nf_register_sysctl_table(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;
	nf_unregister_sysctl_table(*header, table);
	*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_l4proto *
	nf_ct_l4proto_find_get(u_int16_t l3proto, u_int8_t l4proto)
	{
	struct nf_conntrack_l4proto *p;

	rcu_read_lock();
	p = __nf_ct_l4proto_find(l3proto, l4proto);
	if (!try_module_get(p->me))
	p = &nf_conntrack_l4proto_generic;
	rcu_read_unlock();

	return p;
	}
	EXPORT_SYMBOL_GPL(nf_ct_l4proto_find_get);

	void nf_ct_l4proto_put(struct nf_conntrack_l4proto *p)
	{
	module_put(p->me);
	}
	EXPORT_SYMBOL_GPL(nf_ct_l4proto_put);

	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 */
	p = __nf_ct_l3proto_find(l3proto);
	module_put(p->me);
	}
	EXPORT_SYMBOL_GPL(nf_ct_l3proto_module_put);

	static int kill_l3proto(struct nf_conn i, void data)
	{
	return (i->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num ==
	((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 (i->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum ==
	l4proto->l4proto) &&
	(i->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num ==
	l4proto->l3proto);
	}

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

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

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

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

	if (proto->l3proto >= AF_MAX) {
	ret = -EBUSY;
	goto out;
	}

	write_lock_bh(&nf_conntrack_lock);
	if (nf_ct_l3protos[proto->l3proto] != &nf_conntrack_l3proto_generic) {
	ret = -EBUSY;
	goto out_unlock;
	}
	rcu_assign_pointer(nf_ct_l3protos[proto->l3proto], proto);
	write_unlock_bh(&nf_conntrack_lock);

	ret = nf_ct_l3proto_register_sysctl(proto);
	if (ret < 0)
	nf_conntrack_l3proto_unregister(proto);
	return ret;

	out_unlock:
	write_unlock_bh(&nf_conntrack_lock);
	out:
	return ret;
	}
	EXPORT_SYMBOL_GPL(nf_conntrack_l3proto_register);

	void nf_conntrack_l3proto_unregister(struct nf_conntrack_l3proto *proto)
	{
	BUG_ON(proto->l3proto >= AF_MAX);

	write_lock_bh(&nf_conntrack_lock);
	BUG_ON(nf_ct_l3protos[proto->l3proto] != proto);
	rcu_assign_pointer(nf_ct_l3protos[proto->l3proto],
	&nf_conntrack_l3proto_generic);
	write_unlock_bh(&nf_conntrack_lock);
	synchronize_rcu();

	nf_ct_l3proto_unregister_sysctl(proto);

	/* Remove all contrack entries for this protocol */
	nf_ct_iterate_cleanup(kill_l3proto, proto);
	}
	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
	mutex_lock(&nf_ct_proto_sysctl_mutex);
	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:
	mutex_unlock(&nf_ct_proto_sysctl_mutex);
	#endif /* CONFIG_SYSCTL */
	return err;
	}

	static void nf_ct_l4proto_unregister_sysctl(struct nf_conntrack_l4proto *l4proto)
	{
	#ifdef CONFIG_SYSCTL
	mutex_lock(&nf_ct_proto_sysctl_mutex);
	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 */
	mutex_unlock(&nf_ct_proto_sysctl_mutex);
	#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) {
	ret = -EBUSY;
	goto out;
	}

	if (l4proto == &nf_conntrack_l4proto_generic)
	return nf_ct_l4proto_register_sysctl(l4proto);

	retry:
	write_lock_bh(&nf_conntrack_lock);
	if (nf_ct_protos[l4proto->l3proto]) {
	if (nf_ct_protos[l4proto->l3proto][l4proto->l4proto]
	!= &nf_conntrack_l4proto_generic) {
	ret = -EBUSY;
	goto out_unlock;
	}
	} else {
	/* l3proto may be loaded latter. */
	struct nf_conntrack_l4proto **proto_array;
	int i;

	write_unlock_bh(&nf_conntrack_lock);

	proto_array = (struct nf_conntrack_l4proto **)
	kmalloc(MAX_NF_CT_PROTO *
	sizeof(struct nf_conntrack_l4proto *),
	GFP_KERNEL);
	if (proto_array == NULL) {
	ret = -ENOMEM;
	goto out;
	}
	for (i = 0; i < MAX_NF_CT_PROTO; i++)
	proto_array[i] = &nf_conntrack_l4proto_generic;

	write_lock_bh(&nf_conntrack_lock);
	if (nf_ct_protos[l4proto->l3proto]) {
	/* bad timing, but no problem */
	write_unlock_bh(&nf_conntrack_lock);
	kfree(proto_array);
	} else {
	nf_ct_protos[l4proto->l3proto] = proto_array;
	write_unlock_bh(&nf_conntrack_lock);
	}

	/*
	* Just once because array is never freed until unloading
	* nf_conntrack.ko
	*/
	goto retry;
	}

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

	ret = nf_ct_l4proto_register_sysctl(l4proto);
	if (ret < 0)
	nf_conntrack_l4proto_unregister(l4proto);
	return ret;

	out_unlock:
	write_unlock_bh(&nf_conntrack_lock);
	out:
	return ret;
	}
	EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_register);

	void nf_conntrack_l4proto_unregister(struct nf_conntrack_l4proto *l4proto)
	{
	BUG_ON(l4proto->l3proto >= PF_MAX);

	if (l4proto == &nf_conntrack_l4proto_generic) {
	nf_ct_l4proto_unregister_sysctl(l4proto);
	return;
	}

	write_lock_bh(&nf_conntrack_lock);
	BUG_ON(nf_ct_protos[l4proto->l3proto][l4proto->l4proto] != l4proto);
	rcu_assign_pointer(nf_ct_protos[l4proto->l3proto][l4proto->l4proto],
	&nf_conntrack_l4proto_generic);
	write_unlock_bh(&nf_conntrack_lock);
	synchronize_rcu();

	nf_ct_l4proto_unregister_sysctl(l4proto);

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