[GitHub/mt8127/android_kernel_alcatel_ttab.git] / net / netfilter / nfnetlink.c

/* Netfilter messages via netlink socket. Allows for user space
 * protocol helpers and general trouble making from userspace.
 *
 * (C) 2001 by Jay Schulist <jschlst@samba.org>,
 * (C) 2002-2005 by Harald Welte <laforge@gnumonks.org>
 * (C) 2005,2007 by Pablo Neira Ayuso <pablo@netfilter.org>
 *
 * Initial netfilter messages via netlink development funded and
 * generally made possible by Network Robots, Inc. (www.networkrobots.com)
 *
 * Further development of this code funded by Astaro AG (http://www.astaro.com)
 *
 * This software may be used and distributed according to the terms
 * of the GNU General Public License, incorporated herein by reference.
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/skbuff.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <net/sock.h>
#include <net/netlink.h>
#include <linux/init.h>

#include <linux/netlink.h>
#include <linux/netfilter/nfnetlink.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NETFILTER);

static char __initdata nfversion[] = "0.30";

static const struct nfnetlink_subsystem __rcu *subsys_table[NFNL_SUBSYS_COUNT];
static DEFINE_MUTEX(nfnl_mutex);

void nfnl_lock(void)
{
	mutex_lock(&nfnl_mutex);
}
EXPORT_SYMBOL_GPL(nfnl_lock);

void nfnl_unlock(void)
{
	mutex_unlock(&nfnl_mutex);
}
EXPORT_SYMBOL_GPL(nfnl_unlock);

int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n)
{
	nfnl_lock();
	if (subsys_table[n->subsys_id]) {
		nfnl_unlock();
		return -EBUSY;
	}
	RCU_INIT_POINTER(subsys_table[n->subsys_id], n);
	nfnl_unlock();

	return 0;
}
EXPORT_SYMBOL_GPL(nfnetlink_subsys_register);

int nfnetlink_subsys_unregister(const struct nfnetlink_subsystem *n)
{
	nfnl_lock();
	subsys_table[n->subsys_id] = NULL;
	nfnl_unlock();
	synchronize_rcu();
	return 0;
}
EXPORT_SYMBOL_GPL(nfnetlink_subsys_unregister);

static inline const struct nfnetlink_subsystem *nfnetlink_get_subsys(u_int16_t type)
{
	u_int8_t subsys_id = NFNL_SUBSYS_ID(type);

	if (subsys_id >= NFNL_SUBSYS_COUNT)
		return NULL;

	return rcu_dereference(subsys_table[subsys_id]);
}

static inline const struct nfnl_callback *
nfnetlink_find_client(u_int16_t type, const struct nfnetlink_subsystem *ss)
{
	u_int8_t cb_id = NFNL_MSG_TYPE(type);

	if (cb_id >= ss->cb_count)
		return NULL;

	return &ss->cb[cb_id];
}

int nfnetlink_has_listeners(struct net *net, unsigned int group)
{
	return netlink_has_listeners(net->nfnl, group);
}
EXPORT_SYMBOL_GPL(nfnetlink_has_listeners);

int nfnetlink_send(struct sk_buff *skb, struct net *net, u32 pid,
		   unsigned group, int echo, gfp_t flags)
{
	return nlmsg_notify(net->nfnl, skb, pid, group, echo, flags);
}
EXPORT_SYMBOL_GPL(nfnetlink_send);

int nfnetlink_set_err(struct net *net, u32 pid, u32 group, int error)
{
	return netlink_set_err(net->nfnl, pid, group, error);
}
EXPORT_SYMBOL_GPL(nfnetlink_set_err);

int nfnetlink_unicast(struct sk_buff *skb, struct net *net, u_int32_t pid, int flags)
{
	return netlink_unicast(net->nfnl, skb, pid, flags);
}
EXPORT_SYMBOL_GPL(nfnetlink_unicast);

/* Process one complete nfnetlink message. */
static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
{
	struct net *net = sock_net(skb->sk);
	const struct nfnl_callback *nc;
	const struct nfnetlink_subsystem *ss;
	int type, err;

	if (security_netlink_recv(skb, CAP_NET_ADMIN))
		return -EPERM;

	/* All the messages must at least contain nfgenmsg */
	if (nlh->nlmsg_len < NLMSG_LENGTH(sizeof(struct nfgenmsg)))
		return 0;

	type = nlh->nlmsg_type;
replay:
	rcu_read_lock();
	ss = nfnetlink_get_subsys(type);
	if (!ss) {
#ifdef CONFIG_MODULES
		rcu_read_unlock();
		request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type));
		rcu_read_lock();
		ss = nfnetlink_get_subsys(type);
		if (!ss)
#endif
		{
			rcu_read_unlock();
			return -EINVAL;
		}
	}

	nc = nfnetlink_find_client(type, ss);
	if (!nc) {
		rcu_read_unlock();
		return -EINVAL;
	}

	{
		int min_len = NLMSG_SPACE(sizeof(struct nfgenmsg));
		u_int8_t cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
		struct nlattr *cda[ss->cb[cb_id].attr_count + 1];
		struct nlattr *attr = (void *)nlh + min_len;
		int attrlen = nlh->nlmsg_len - min_len;

		err = nla_parse(cda, ss->cb[cb_id].attr_count,
				attr, attrlen, ss->cb[cb_id].policy);
		if (err < 0)
			return err;

		if (nc->call_rcu) {
			err = nc->call_rcu(net->nfnl, skb, nlh,
					   (const struct nlattr **)cda);
			rcu_read_unlock();
		} else {
			rcu_read_unlock();
			nfnl_lock();
			if (rcu_dereference_protected(
					subsys_table[NFNL_SUBSYS_ID(type)],
					lockdep_is_held(&nfnl_mutex)) != ss ||
			    nfnetlink_find_client(type, ss) != nc)
				err = -EAGAIN;
			else
				err = nc->call(net->nfnl, skb, nlh,
						   (const struct nlattr **)cda);
			nfnl_unlock();
		}
		if (err == -EAGAIN)
			goto replay;
		return err;
	}
}

static void nfnetlink_rcv(struct sk_buff *skb)
{
	netlink_rcv_skb(skb, &nfnetlink_rcv_msg);
}

static int __net_init nfnetlink_net_init(struct net *net)
{
	struct sock *nfnl;

	nfnl = netlink_kernel_create(net, NETLINK_NETFILTER, NFNLGRP_MAX,
				     nfnetlink_rcv, NULL, THIS_MODULE);
	if (!nfnl)
		return -ENOMEM;
	net->nfnl_stash = nfnl;
	RCU_INIT_POINTER(net->nfnl, nfnl);
	return 0;
}

static void __net_exit nfnetlink_net_exit_batch(struct list_head *net_exit_list)
{
	struct net *net;

	list_for_each_entry(net, net_exit_list, exit_list)
		RCU_INIT_POINTER(net->nfnl, NULL);
	synchronize_net();
	list_for_each_entry(net, net_exit_list, exit_list)
		netlink_kernel_release(net->nfnl_stash);
}

static struct pernet_operations nfnetlink_net_ops = {
	.init		= nfnetlink_net_init,
	.exit_batch	= nfnetlink_net_exit_batch,
};

static int __init nfnetlink_init(void)
{
	pr_info("Netfilter messages via NETLINK v%s.\n", nfversion);
	return register_pernet_subsys(&nfnetlink_net_ops);
}

static void __exit nfnetlink_exit(void)
{
	pr_info("Removing netfilter NETLINK layer.\n");
	unregister_pernet_subsys(&nfnetlink_net_ops);
}
module_init(nfnetlink_init);
module_exit(nfnetlink_exit);
Commit	Line	Data
f9e815b3 HW	1	/* Netfilter messages via netlink socket. Allows for user space
	2	* protocol helpers and general trouble making from userspace.
	3	*
	4	* (C) 2001 by Jay Schulist <jschlst@samba.org>,
	5	* (C) 2002-2005 by Harald Welte <laforge@gnumonks.org>
67ca3966	6	* (C) 2005,2007 by Pablo Neira Ayuso <pablo@netfilter.org>
f9e815b3 HW	7	*
	8	* Initial netfilter messages via netlink development funded and
	9	* generally made possible by Network Robots, Inc. (www.networkrobots.com)
	10	*
	11	* Further development of this code funded by Astaro AG (http://www.astaro.com)
	12	*
	13	* This software may be used and distributed according to the terms
	14	* of the GNU General Public License, incorporated herein by reference.
	15	*/
	16
f9e815b3 HW	17	#include <linux/module.h>
	18	#include <linux/types.h>
	19	#include <linux/socket.h>
	20	#include <linux/kernel.h>
f9e815b3 HW	21	#include <linux/string.h>
	22	#include <linux/sockios.h>
	23	#include <linux/net.h>
f9e815b3 HW	24	#include <linux/skbuff.h>
	25	#include <asm/uaccess.h>
	26	#include <asm/system.h>
	27	#include <net/sock.h>
a3c5029c	28	#include <net/netlink.h>
f9e815b3	29	#include <linux/init.h>
f9e815b3	30
f9e815b3 HW	31	#include <linux/netlink.h>
	32	#include <linux/netfilter/nfnetlink.h>
	33
	34	MODULE_LICENSE("GPL");
4fdb3bb7 HW	35	MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
4fdb3bb7 HW	36	MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NETFILTER);
f9e815b3 HW	37
	38	static char __initdata nfversion[] = "0.30";
	39
6b75e3e8	40	static const struct nfnetlink_subsystem __rcu *subsys_table[NFNL_SUBSYS_COUNT];
a3c5029c	41	static DEFINE_MUTEX(nfnl_mutex);
f9e815b3	42
e6a7d3c0	43	void nfnl_lock(void)
f9e815b3	44	{
a3c5029c	45	mutex_lock(&nfnl_mutex);
f9e815b3	46	}
e6a7d3c0	47	EXPORT_SYMBOL_GPL(nfnl_lock);
f9e815b3	48
e6a7d3c0	49	void nfnl_unlock(void)
a3c5029c PM	50	{
a3c5029c PM	51	mutex_unlock(&nfnl_mutex);
f9e815b3	52	}
e6a7d3c0	53	EXPORT_SYMBOL_GPL(nfnl_unlock);
f9e815b3	54
7c8d4cb4	55	int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n)
f9e815b3	56	{
f9e815b3	57	nfnl_lock();
0ab43f84 HW	58	if (subsys_table[n->subsys_id]) {
	59	nfnl_unlock();
	60	return -EBUSY;
	61	}
a9b3cd7f	62	RCU_INIT_POINTER(subsys_table[n->subsys_id], n);
f9e815b3 HW	63	nfnl_unlock();
	64
	65	return 0;
	66	}
f4bc177f	67	EXPORT_SYMBOL_GPL(nfnetlink_subsys_register);
f9e815b3	68
7c8d4cb4	69	int nfnetlink_subsys_unregister(const struct nfnetlink_subsystem *n)
f9e815b3	70	{
f9e815b3 HW	71	nfnl_lock();
	72	subsys_table[n->subsys_id] = NULL;
	73	nfnl_unlock();
6b75e3e8	74	synchronize_rcu();
f9e815b3 HW	75	return 0;
f9e815b3 HW	76	}
f4bc177f	77	EXPORT_SYMBOL_GPL(nfnetlink_subsys_unregister);
f9e815b3	78
7c8d4cb4	79	static inline const struct nfnetlink_subsystem *nfnetlink_get_subsys(u_int16_t type)
f9e815b3 HW	80	{
	81	u_int8_t subsys_id = NFNL_SUBSYS_ID(type);
	82
ac0f1d98	83	if (subsys_id >= NFNL_SUBSYS_COUNT)
f9e815b3 HW	84	return NULL;
f9e815b3 HW	85
6b75e3e8	86	return rcu_dereference(subsys_table[subsys_id]);
f9e815b3 HW	87	}
f9e815b3 HW	88
7c8d4cb4 PM	89	static inline const struct nfnl_callback *
7c8d4cb4 PM	90	nfnetlink_find_client(u_int16_t type, const struct nfnetlink_subsystem *ss)
f9e815b3 HW	91	{
f9e815b3 HW	92	u_int8_t cb_id = NFNL_MSG_TYPE(type);
601e68e1	93
67ca3966	94	if (cb_id >= ss->cb_count)
f9e815b3	95	return NULL;
f9e815b3 HW	96
	97	return &ss->cb[cb_id];
	98	}
	99
cd8c20b6	100	int nfnetlink_has_listeners(struct net *net, unsigned int group)
a2427692	101	{
cd8c20b6	102	return netlink_has_listeners(net->nfnl, group);
a2427692 PM	103	}
	104	EXPORT_SYMBOL_GPL(nfnetlink_has_listeners);
	105
cd8c20b6	106	int nfnetlink_send(struct sk_buff skb, struct net net, u32 pid,
e34d5c1a	107	unsigned group, int echo, gfp_t flags)
f9e815b3	108	{
cd8c20b6	109	return nlmsg_notify(net->nfnl, skb, pid, group, echo, flags);
f9e815b3	110	}
f4bc177f	111	EXPORT_SYMBOL_GPL(nfnetlink_send);
f9e815b3	112
37b7ef72	113	int nfnetlink_set_err(struct net *net, u32 pid, u32 group, int error)
dd5b6ce6	114	{
37b7ef72	115	return netlink_set_err(net->nfnl, pid, group, error);
dd5b6ce6 PNA	116	}
	117	EXPORT_SYMBOL_GPL(nfnetlink_set_err);
	118
cd8c20b6	119	int nfnetlink_unicast(struct sk_buff skb, struct net net, u_int32_t pid, int flags)
f9e815b3	120	{
cd8c20b6	121	return netlink_unicast(net->nfnl, skb, pid, flags);
f9e815b3	122	}
f4bc177f	123	EXPORT_SYMBOL_GPL(nfnetlink_unicast);
f9e815b3 HW	124
f9e815b3 HW	125	/* Process one complete nfnetlink message. */
1d00a4eb	126	static int nfnetlink_rcv_msg(struct sk_buff skb, struct nlmsghdr nlh)
f9e815b3	127	{
cd8c20b6	128	struct net *net = sock_net(skb->sk);
7c8d4cb4 PM	129	const struct nfnl_callback *nc;
7c8d4cb4 PM	130	const struct nfnetlink_subsystem *ss;
1d00a4eb	131	int type, err;
f9e815b3	132
1d00a4eb TG	133	if (security_netlink_recv(skb, CAP_NET_ADMIN))
1d00a4eb TG	134	return -EPERM;
37d2e7a2	135
f9e815b3	136	/* All the messages must at least contain nfgenmsg */
f49c857f	137	if (nlh->nlmsg_len < NLMSG_LENGTH(sizeof(struct nfgenmsg)))
f9e815b3	138	return 0;
f9e815b3 HW	139
f9e815b3 HW	140	type = nlh->nlmsg_type;
e6a7d3c0	141	replay:
6b75e3e8	142	rcu_read_lock();
f9e815b3	143	ss = nfnetlink_get_subsys(type);
0ab43f84	144	if (!ss) {
95a5afca	145	#ifdef CONFIG_MODULES
6b75e3e8	146	rcu_read_unlock();
37d2e7a2	147	request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type));
6b75e3e8	148	rcu_read_lock();
37d2e7a2	149	ss = nfnetlink_get_subsys(type);
0ab43f84 HW	150	if (!ss)
0ab43f84 HW	151	#endif
6b75e3e8 ED	152	{
6b75e3e8 ED	153	rcu_read_unlock();
1d00a4eb	154	return -EINVAL;
6b75e3e8	155	}
0ab43f84	156	}
f9e815b3 HW	157
f9e815b3 HW	158	nc = nfnetlink_find_client(type, ss);
6b75e3e8 ED	159	if (!nc) {
6b75e3e8 ED	160	rcu_read_unlock();
1d00a4eb	161	return -EINVAL;
6b75e3e8	162	}
f9e815b3	163
f9e815b3	164	{
e3730578 PM	165	int min_len = NLMSG_SPACE(sizeof(struct nfgenmsg));
e3730578 PM	166	u_int8_t cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
f49c857f PNA	167	struct nlattr *cda[ss->cb[cb_id].attr_count + 1];
	168	struct nlattr attr = (void )nlh + min_len;
	169	int attrlen = nlh->nlmsg_len - min_len;
	170
	171	err = nla_parse(cda, ss->cb[cb_id].attr_count,
	172	attr, attrlen, ss->cb[cb_id].policy);
	173	if (err < 0)
	174	return err;
601e68e1	175
6b75e3e8 ED	176	if (nc->call_rcu) {
	177	err = nc->call_rcu(net->nfnl, skb, nlh,
	178	(const struct nlattr **)cda);
	179	rcu_read_unlock();
	180	} else {
	181	rcu_read_unlock();
	182	nfnl_lock();
	183	if (rcu_dereference_protected(
	184	subsys_table[NFNL_SUBSYS_ID(type)],
	185	lockdep_is_held(&nfnl_mutex)) != ss \|\|
	186	nfnetlink_find_client(type, ss) != nc)
	187	err = -EAGAIN;
	188	else
	189	err = nc->call(net->nfnl, skb, nlh,
	190	(const struct nlattr **)cda);
	191	nfnl_unlock();
	192	}
e6a7d3c0 PNA	193	if (err == -EAGAIN)
	194	goto replay;
	195	return err;
f9e815b3	196	}
f9e815b3 HW	197	}
f9e815b3 HW	198
cd40b7d3	199	static void nfnetlink_rcv(struct sk_buff *skb)
f9e815b3	200	{
cd40b7d3	201	netlink_rcv_skb(skb, &nfnetlink_rcv_msg);
f9e815b3 HW	202	}
f9e815b3 HW	203
cd8c20b6	204	static int __net_init nfnetlink_net_init(struct net *net)
f9e815b3	205	{
cd8c20b6 AD	206	struct sock *nfnl;
	207
	208	nfnl = netlink_kernel_create(net, NETLINK_NETFILTER, NFNLGRP_MAX,
	209	nfnetlink_rcv, NULL, THIS_MODULE);
	210	if (!nfnl)
	211	return -ENOMEM;
	212	net->nfnl_stash = nfnl;
a9b3cd7f	213	RCU_INIT_POINTER(net->nfnl, nfnl);
cd8c20b6	214	return 0;
f9e815b3 HW	215	}
f9e815b3 HW	216
cd8c20b6	217	static void __net_exit nfnetlink_net_exit_batch(struct list_head *net_exit_list)
f9e815b3	218	{
cd8c20b6	219	struct net *net;
f9e815b3	220
cd8c20b6	221	list_for_each_entry(net, net_exit_list, exit_list)
a9b3cd7f	222	RCU_INIT_POINTER(net->nfnl, NULL);
cd8c20b6 AD	223	synchronize_net();
	224	list_for_each_entry(net, net_exit_list, exit_list)
	225	netlink_kernel_release(net->nfnl_stash);
	226	}
f9e815b3	227
cd8c20b6 AD	228	static struct pernet_operations nfnetlink_net_ops = {
	229	.init = nfnetlink_net_init,
	230	.exit_batch = nfnetlink_net_exit_batch,
	231	};
	232
	233	static int __init nfnetlink_init(void)
	234	{
654d0fbd	235	pr_info("Netfilter messages via NETLINK v%s.\n", nfversion);
cd8c20b6	236	return register_pernet_subsys(&nfnetlink_net_ops);
f9e815b3 HW	237	}
f9e815b3 HW	238
cd8c20b6 AD	239	static void __exit nfnetlink_exit(void)
cd8c20b6 AD	240	{
654d0fbd	241	pr_info("Removing netfilter NETLINK layer.\n");
cd8c20b6 AD	242	unregister_pernet_subsys(&nfnetlink_net_ops);
cd8c20b6 AD	243	}
f9e815b3 HW	244	module_init(nfnetlink_init);
f9e815b3 HW	245	module_exit(nfnetlink_exit);