[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 by Pablo Neira Ayuso <pablo@eurodev.net>
 *
 * 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/major.h>
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/fcntl.h>
#include <linux/skbuff.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <net/sock.h>
#include <linux/init.h>
#include <linux/spinlock.h>

#include <linux/netfilter.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";

#if 0
#define DEBUGP(format, args...)	\
		printk(KERN_DEBUG "%s(%d):%s(): " format, __FILE__, \
			__LINE__, __FUNCTION__, ## args)
#else
#define DEBUGP(format, args...)
#endif

static struct sock *nfnl = NULL;
static struct nfnetlink_subsystem *subsys_table[NFNL_SUBSYS_COUNT];
DECLARE_MUTEX(nfnl_sem);

void nfnl_lock(void)
{
	nfnl_shlock();
}

void nfnl_unlock(void)
{
	nfnl_shunlock();
}

int nfnetlink_subsys_register(struct nfnetlink_subsystem *n)
{
	DEBUGP("registering subsystem ID %u\n", n->subsys_id);

	nfnl_lock();
	if (subsys_table[n->subsys_id]) {
		nfnl_unlock();
		return -EBUSY;
	}
	subsys_table[n->subsys_id] = n;
	nfnl_unlock();

	return 0;
}

int nfnetlink_subsys_unregister(struct nfnetlink_subsystem *n)
{
	DEBUGP("unregistering subsystem ID %u\n", n->subsys_id);

	nfnl_lock();
	subsys_table[n->subsys_id] = NULL;
	nfnl_unlock();

	return 0;
}

static inline 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
	    || subsys_table[subsys_id] == NULL)
		return NULL;

	return subsys_table[subsys_id];
}

static inline struct nfnl_callback *
nfnetlink_find_client(u_int16_t type, struct nfnetlink_subsystem *ss)
{
	u_int8_t cb_id = NFNL_MSG_TYPE(type);
	
	if (cb_id >= ss->cb_count) {
		DEBUGP("msgtype %u >= %u, returning\n", type, ss->cb_count);
		return NULL;
	}

	return &ss->cb[cb_id];
}

void __nfa_fill(struct sk_buff *skb, int attrtype, int attrlen,
		const void *data)
{
	struct nfattr *nfa;
	int size = NFA_LENGTH(attrlen);

	nfa = (struct nfattr *)skb_put(skb, NFA_ALIGN(size));
	nfa->nfa_type = attrtype;
	nfa->nfa_len  = size;
	memcpy(NFA_DATA(nfa), data, attrlen);
	memset(NFA_DATA(nfa) + attrlen, 0, NFA_ALIGN(size) - size);
}

void nfattr_parse(struct nfattr *tb[], int maxattr, struct nfattr *nfa, int len)
{
	memset(tb, 0, sizeof(struct nfattr *) * maxattr);

	while (NFA_OK(nfa, len)) {
		unsigned flavor = NFA_TYPE(nfa);
		if (flavor && flavor <= maxattr)
			tb[flavor-1] = nfa;
		nfa = NFA_NEXT(nfa, len);
	}
}

/**
 * nfnetlink_check_attributes - check and parse nfnetlink attributes
 *
 * subsys: nfnl subsystem for which this message is to be parsed
 * nlmsghdr: netlink message to be checked/parsed
 * cda: array of pointers, needs to be at least subsys->attr_count big
 *
 */
static int
nfnetlink_check_attributes(struct nfnetlink_subsystem *subsys,
			   struct nlmsghdr *nlh, struct nfattr *cda[])
{
	int min_len;
	u_int16_t attr_count;
	u_int8_t cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);

	if (unlikely(cb_id >= subsys->cb_count)) {
		DEBUGP("msgtype %u >= %u, returning\n",
			cb_id, subsys->cb_count);
		return -EINVAL;
	}

	min_len = NLMSG_SPACE(sizeof(struct nfgenmsg));
	if (unlikely(nlh->nlmsg_len < min_len))
		return -EINVAL;

	attr_count = subsys->cb[cb_id].attr_count;
	memset(cda, 0, sizeof(struct nfattr *) * attr_count);

	/* check attribute lengths. */
	if (likely(nlh->nlmsg_len > min_len)) {
		struct nfattr *attr = NFM_NFA(NLMSG_DATA(nlh));
		int attrlen = nlh->nlmsg_len - NLMSG_ALIGN(min_len);

		while (NFA_OK(attr, attrlen)) {
			unsigned flavor = NFA_TYPE(attr);
			if (flavor) {
				if (flavor > attr_count)
					return -EINVAL;
				cda[flavor - 1] = attr;
			}
			attr = NFA_NEXT(attr, attrlen);
		}
	}

	/* implicit: if nlmsg_len == min_len, we return 0, and an empty
	 * (zeroed) cda[] array. The message is valid, but empty. */

        return 0;
}

int nfnetlink_has_listeners(unsigned int group)
{
	return netlink_has_listeners(nfnl, group);
}
EXPORT_SYMBOL_GPL(nfnetlink_has_listeners);

int nfnetlink_send(struct sk_buff *skb, u32 pid, unsigned group, int echo)
{
	gfp_t allocation = in_interrupt() ? GFP_ATOMIC : GFP_KERNEL;
	int err = 0;

	NETLINK_CB(skb).dst_group = group;
	if (echo)
		atomic_inc(&skb->users);
	netlink_broadcast(nfnl, skb, pid, group, allocation);
	if (echo)
		err = netlink_unicast(nfnl, skb, pid, MSG_DONTWAIT);

	return err;
}

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

/* Process one complete nfnetlink message. */
static int nfnetlink_rcv_msg(struct sk_buff *skb,
				    struct nlmsghdr *nlh, int *errp)
{
	struct nfnl_callback *nc;
	struct nfnetlink_subsystem *ss;
	int type, err = 0;

	DEBUGP("entered; subsys=%u, msgtype=%u\n",
		 NFNL_SUBSYS_ID(nlh->nlmsg_type),
		 NFNL_MSG_TYPE(nlh->nlmsg_type));

	if (security_netlink_recv(skb, CAP_NET_ADMIN)) {
		DEBUGP("missing CAP_NET_ADMIN\n");
		*errp = -EPERM;
		return -1;
	}

	/* Only requests are handled by kernel now. */
	if (!(nlh->nlmsg_flags & NLM_F_REQUEST)) {
		DEBUGP("received non-request message\n");
		return 0;
	}

	/* All the messages must at least contain nfgenmsg */
	if (nlh->nlmsg_len < NLMSG_SPACE(sizeof(struct nfgenmsg))) {
		DEBUGP("received message was too short\n");
		return 0;
	}

	type = nlh->nlmsg_type;
	ss = nfnetlink_get_subsys(type);
	if (!ss) {
#ifdef CONFIG_KMOD
		/* don't call nfnl_shunlock, since it would reenter
		 * with further packet processing */
		up(&nfnl_sem);
		request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type));
		nfnl_shlock();
		ss = nfnetlink_get_subsys(type);
		if (!ss)
#endif
			goto err_inval;
	}

	nc = nfnetlink_find_client(type, ss);
	if (!nc) {
		DEBUGP("unable to find client for type %d\n", type);
		goto err_inval;
	}

	{
		u_int16_t attr_count = 
			ss->cb[NFNL_MSG_TYPE(nlh->nlmsg_type)].attr_count;
		struct nfattr *cda[attr_count];

		memset(cda, 0, sizeof(struct nfattr *) * attr_count);
		
		err = nfnetlink_check_attributes(ss, nlh, cda);
		if (err < 0)
			goto err_inval;

		DEBUGP("calling handler\n");
		err = nc->call(nfnl, skb, nlh, cda, errp);
		*errp = err;
		return err;
	}

err_inval:
	DEBUGP("returning -EINVAL\n");
	*errp = -EINVAL;
	return -1;
}

/* Process one packet of messages. */
static inline int nfnetlink_rcv_skb(struct sk_buff *skb)
{
	int err;
	struct nlmsghdr *nlh;

	while (skb->len >= NLMSG_SPACE(0)) {
		u32 rlen;

		nlh = (struct nlmsghdr *)skb->data;
		if (nlh->nlmsg_len < sizeof(struct nlmsghdr)
		    || skb->len < nlh->nlmsg_len)
			return 0;
		rlen = NLMSG_ALIGN(nlh->nlmsg_len);
		if (rlen > skb->len)
			rlen = skb->len;
		if (nfnetlink_rcv_msg(skb, nlh, &err)) {
			if (!err)
				return -1;
			netlink_ack(skb, nlh, err);
		} else
			if (nlh->nlmsg_flags & NLM_F_ACK)
				netlink_ack(skb, nlh, 0);
		skb_pull(skb, rlen);
	}

	return 0;
}

static void nfnetlink_rcv(struct sock *sk, int len)
{
	do {
		struct sk_buff *skb;

		if (nfnl_shlock_nowait())
			return;

		while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
			if (nfnetlink_rcv_skb(skb)) {
				if (skb->len)
					skb_queue_head(&sk->sk_receive_queue,
						       skb);
				else
					kfree_skb(skb);
				break;
			}
			kfree_skb(skb);
		}

		/* don't call nfnl_shunlock, since it would reenter
		 * with further packet processing */
		up(&nfnl_sem);
	} while(nfnl && nfnl->sk_receive_queue.qlen);
}

static void __exit nfnetlink_exit(void)
{
	printk("Removing netfilter NETLINK layer.\n");
	sock_release(nfnl->sk_socket);
	return;
}

static int __init nfnetlink_init(void)
{
	printk("Netfilter messages via NETLINK v%s.\n", nfversion);

	nfnl = netlink_kernel_create(NETLINK_NETFILTER, NFNLGRP_MAX,
	                             nfnetlink_rcv, THIS_MODULE);
	if (!nfnl) {
		printk(KERN_ERR "cannot initialize nfnetlink!\n");
		return -1;
	}

	return 0;
}

module_init(nfnetlink_init);
module_exit(nfnetlink_exit);

EXPORT_SYMBOL_GPL(nfnetlink_subsys_register);
EXPORT_SYMBOL_GPL(nfnetlink_subsys_unregister);
EXPORT_SYMBOL_GPL(nfnetlink_send);
EXPORT_SYMBOL_GPL(nfnetlink_unicast);
EXPORT_SYMBOL_GPL(nfattr_parse);
EXPORT_SYMBOL_GPL(__nfa_fill);
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>
	6	* (C) 2005 by Pablo Neira Ayuso <pablo@eurodev.net>
	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>
	21	#include <linux/major.h>
	22	#include <linux/sched.h>
	23	#include <linux/timer.h>
	24	#include <linux/string.h>
	25	#include <linux/sockios.h>
	26	#include <linux/net.h>
	27	#include <linux/fcntl.h>
	28	#include <linux/skbuff.h>
	29	#include <asm/uaccess.h>
	30	#include <asm/system.h>
	31	#include <net/sock.h>
	32	#include <linux/init.h>
	33	#include <linux/spinlock.h>
	34
	35	#include <linux/netfilter.h>
	36	#include <linux/netlink.h>
	37	#include <linux/netfilter/nfnetlink.h>
	38
	39	MODULE_LICENSE("GPL");
4fdb3bb7 HW	40	MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
4fdb3bb7 HW	41	MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NETFILTER);
f9e815b3 HW	42
	43	static char __initdata nfversion[] = "0.30";
	44
	45	#if 0
0ab43f84 HW	46	#define DEBUGP(format, args...) \
	47	printk(KERN_DEBUG "%s(%d):%s(): " format, __FILE__, \
	48	__LINE__, __FUNCTION__, ## args)
f9e815b3 HW	49	#else
	50	#define DEBUGP(format, args...)
	51	#endif
	52
	53	static struct sock *nfnl = NULL;
	54	static struct nfnetlink_subsystem *subsys_table[NFNL_SUBSYS_COUNT];
	55	DECLARE_MUTEX(nfnl_sem);
	56
	57	void nfnl_lock(void)
	58	{
	59	nfnl_shlock();
	60	}
	61
	62	void nfnl_unlock(void)
	63	{
	64	nfnl_shunlock();
	65	}
	66
	67	int nfnetlink_subsys_register(struct nfnetlink_subsystem *n)
	68	{
	69	DEBUGP("registering subsystem ID %u\n", n->subsys_id);
	70
f9e815b3	71	nfnl_lock();
0ab43f84 HW	72	if (subsys_table[n->subsys_id]) {
	73	nfnl_unlock();
	74	return -EBUSY;
	75	}
f9e815b3 HW	76	subsys_table[n->subsys_id] = n;
	77	nfnl_unlock();
	78
	79	return 0;
	80	}
	81
	82	int nfnetlink_subsys_unregister(struct nfnetlink_subsystem *n)
	83	{
	84	DEBUGP("unregistering subsystem ID %u\n", n->subsys_id);
	85
	86	nfnl_lock();
	87	subsys_table[n->subsys_id] = NULL;
	88	nfnl_unlock();
	89
	90	return 0;
	91	}
	92
	93	static inline struct nfnetlink_subsystem *nfnetlink_get_subsys(u_int16_t type)
	94	{
	95	u_int8_t subsys_id = NFNL_SUBSYS_ID(type);
	96
	97	if (subsys_id >= NFNL_SUBSYS_COUNT
	98	\|\| subsys_table[subsys_id] == NULL)
	99	return NULL;
	100
	101	return subsys_table[subsys_id];
	102	}
	103
	104	static inline struct nfnl_callback *
	105	nfnetlink_find_client(u_int16_t type, struct nfnetlink_subsystem *ss)
	106	{
	107	u_int8_t cb_id = NFNL_MSG_TYPE(type);
	108
	109	if (cb_id >= ss->cb_count) {
	110	DEBUGP("msgtype %u >= %u, returning\n", type, ss->cb_count);
	111	return NULL;
	112	}
	113
	114	return &ss->cb[cb_id];
	115	}
	116
	117	void __nfa_fill(struct sk_buff *skb, int attrtype, int attrlen,
	118	const void *data)
	119	{
	120	struct nfattr *nfa;
	121	int size = NFA_LENGTH(attrlen);
	122
	123	nfa = (struct nfattr *)skb_put(skb, NFA_ALIGN(size));
	124	nfa->nfa_type = attrtype;
	125	nfa->nfa_len = size;
	126	memcpy(NFA_DATA(nfa), data, attrlen);
080774a2	127	memset(NFA_DATA(nfa) + attrlen, 0, NFA_ALIGN(size) - size);
f9e815b3 HW	128	}
f9e815b3 HW	129
a2506c04	130	void nfattr_parse(struct nfattr tb[], int maxattr, struct nfattr nfa, int len)
f9e815b3 HW	131	{
	132	memset(tb, 0, sizeof(struct nfattr ) maxattr);
	133
	134	while (NFA_OK(nfa, len)) {
ebe0bbf0	135	unsigned flavor = NFA_TYPE(nfa);
f9e815b3 HW	136	if (flavor && flavor <= maxattr)
	137	tb[flavor-1] = nfa;
	138	nfa = NFA_NEXT(nfa, len);
	139	}
f9e815b3 HW	140	}
	141
	142	/**
	143	* nfnetlink_check_attributes - check and parse nfnetlink attributes
	144	*
	145	* subsys: nfnl subsystem for which this message is to be parsed
	146	* nlmsghdr: netlink message to be checked/parsed
	147	* cda: array of pointers, needs to be at least subsys->attr_count big
	148	*
	149	*/
	150	static int
	151	nfnetlink_check_attributes(struct nfnetlink_subsystem *subsys,
	152	struct nlmsghdr nlh, struct nfattr cda[])
	153	{
	154	int min_len;
927ccbcc HW	155	u_int16_t attr_count;
927ccbcc HW	156	u_int8_t cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
f9e815b3	157
927ccbcc HW	158	if (unlikely(cb_id >= subsys->cb_count)) {
	159	DEBUGP("msgtype %u >= %u, returning\n",
	160	cb_id, subsys->cb_count);
	161	return -EINVAL;
	162	}
f9e815b3	163
3ebbe0cd	164	min_len = NLMSG_SPACE(sizeof(struct nfgenmsg));
a42827b7	165	if (unlikely(nlh->nlmsg_len < min_len))
f9e815b3 HW	166	return -EINVAL;
f9e815b3 HW	167
a42827b7 HW	168	attr_count = subsys->cb[cb_id].attr_count;
	169	memset(cda, 0, sizeof(struct nfattr ) attr_count);
	170
	171	/* check attribute lengths. */
	172	if (likely(nlh->nlmsg_len > min_len)) {
f9e815b3 HW	173	struct nfattr *attr = NFM_NFA(NLMSG_DATA(nlh));
	174	int attrlen = nlh->nlmsg_len - NLMSG_ALIGN(min_len);
	175
	176	while (NFA_OK(attr, attrlen)) {
ebe0bbf0	177	unsigned flavor = NFA_TYPE(attr);
f9e815b3	178	if (flavor) {
927ccbcc	179	if (flavor > attr_count)
f9e815b3 HW	180	return -EINVAL;
	181	cda[flavor - 1] = attr;
	182	}
	183	attr = NFA_NEXT(attr, attrlen);
	184	}
a42827b7 HW	185	}
	186
	187	/* implicit: if nlmsg_len == min_len, we return 0, and an empty
	188	* (zeroed) cda[] array. The message is valid, but empty. */
f9e815b3 HW	189
	190	return 0;
	191	}
	192
a2427692 PM	193	int nfnetlink_has_listeners(unsigned int group)
	194	{
	195	return netlink_has_listeners(nfnl, group);
	196	}
	197	EXPORT_SYMBOL_GPL(nfnetlink_has_listeners);
	198
f9e815b3 HW	199	int nfnetlink_send(struct sk_buff *skb, u32 pid, unsigned group, int echo)
f9e815b3 HW	200	{
dd0fc66f	201	gfp_t allocation = in_interrupt() ? GFP_ATOMIC : GFP_KERNEL;
f9e815b3 HW	202	int err = 0;
f9e815b3 HW	203
ac6d439d	204	NETLINK_CB(skb).dst_group = group;
f9e815b3 HW	205	if (echo)
	206	atomic_inc(&skb->users);
	207	netlink_broadcast(nfnl, skb, pid, group, allocation);
	208	if (echo)
	209	err = netlink_unicast(nfnl, skb, pid, MSG_DONTWAIT);
	210
	211	return err;
	212	}
	213
	214	int nfnetlink_unicast(struct sk_buff *skb, u_int32_t pid, int flags)
	215	{
	216	return netlink_unicast(nfnl, skb, pid, flags);
	217	}
	218
	219	/* Process one complete nfnetlink message. */
858119e1	220	static int nfnetlink_rcv_msg(struct sk_buff *skb,
f9e815b3 HW	221	struct nlmsghdr nlh, int errp)
	222	{
	223	struct nfnl_callback *nc;
	224	struct nfnetlink_subsystem *ss;
	225	int type, err = 0;
	226
	227	DEBUGP("entered; subsys=%u, msgtype=%u\n",
	228	NFNL_SUBSYS_ID(nlh->nlmsg_type),
	229	NFNL_MSG_TYPE(nlh->nlmsg_type));
	230
c7bdb545	231	if (security_netlink_recv(skb, CAP_NET_ADMIN)) {
37d2e7a2 HW	232	DEBUGP("missing CAP_NET_ADMIN\n");
	233	*errp = -EPERM;
	234	return -1;
	235	}
	236
f9e815b3 HW	237	/* Only requests are handled by kernel now. */
	238	if (!(nlh->nlmsg_flags & NLM_F_REQUEST)) {
	239	DEBUGP("received non-request message\n");
	240	return 0;
	241	}
	242
	243	/* All the messages must at least contain nfgenmsg */
3ebbe0cd	244	if (nlh->nlmsg_len < NLMSG_SPACE(sizeof(struct nfgenmsg))) {
f9e815b3 HW	245	DEBUGP("received message was too short\n");
	246	return 0;
	247	}
	248
	249	type = nlh->nlmsg_type;
	250	ss = nfnetlink_get_subsys(type);
0ab43f84 HW	251	if (!ss) {
0ab43f84 HW	252	#ifdef CONFIG_KMOD
37d2e7a2 HW	253	/* don't call nfnl_shunlock, since it would reenter
	254	* with further packet processing */
	255	up(&nfnl_sem);
	256	request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type));
	257	nfnl_shlock();
	258	ss = nfnetlink_get_subsys(type);
0ab43f84 HW	259	if (!ss)
0ab43f84 HW	260	#endif
ed77de9f	261	goto err_inval;
0ab43f84	262	}
f9e815b3 HW	263
	264	nc = nfnetlink_find_client(type, ss);
	265	if (!nc) {
	266	DEBUGP("unable to find client for type %d\n", type);
	267	goto err_inval;
	268	}
	269
f9e815b3	270	{
927ccbcc HW	271	u_int16_t attr_count =
	272	ss->cb[NFNL_MSG_TYPE(nlh->nlmsg_type)].attr_count;
	273	struct nfattr *cda[attr_count];
f9e815b3	274
927ccbcc	275	memset(cda, 0, sizeof(struct nfattr ) attr_count);
f9e815b3 HW	276
	277	err = nfnetlink_check_attributes(ss, nlh, cda);
	278	if (err < 0)
	279	goto err_inval;
	280
0ab43f84	281	DEBUGP("calling handler\n");
f9e815b3 HW	282	err = nc->call(nfnl, skb, nlh, cda, errp);
	283	*errp = err;
	284	return err;
	285	}
	286
	287	err_inval:
0ab43f84	288	DEBUGP("returning -EINVAL\n");
f9e815b3 HW	289	*errp = -EINVAL;
	290	return -1;
	291	}
	292
	293	/* Process one packet of messages. */
	294	static inline int nfnetlink_rcv_skb(struct sk_buff *skb)
	295	{
	296	int err;
	297	struct nlmsghdr *nlh;
	298
	299	while (skb->len >= NLMSG_SPACE(0)) {
	300	u32 rlen;
	301
	302	nlh = (struct nlmsghdr *)skb->data;
	303	if (nlh->nlmsg_len < sizeof(struct nlmsghdr)
	304	\|\| skb->len < nlh->nlmsg_len)
	305	return 0;
	306	rlen = NLMSG_ALIGN(nlh->nlmsg_len);
	307	if (rlen > skb->len)
	308	rlen = skb->len;
	309	if (nfnetlink_rcv_msg(skb, nlh, &err)) {
	310	if (!err)
	311	return -1;
	312	netlink_ack(skb, nlh, err);
	313	} else
	314	if (nlh->nlmsg_flags & NLM_F_ACK)
	315	netlink_ack(skb, nlh, 0);
	316	skb_pull(skb, rlen);
	317	}
	318
	319	return 0;
	320	}
	321
	322	static void nfnetlink_rcv(struct sock *sk, int len)
	323	{
	324	do {
	325	struct sk_buff *skb;
	326
	327	if (nfnl_shlock_nowait())
	328	return;
	329
	330	while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
	331	if (nfnetlink_rcv_skb(skb)) {
	332	if (skb->len)
	333	skb_queue_head(&sk->sk_receive_queue,
	334	skb);
	335	else
	336	kfree_skb(skb);
	337	break;
	338	}
	339	kfree_skb(skb);
	340	}
	341
0ab43f84 HW	342	/* don't call nfnl_shunlock, since it would reenter
0ab43f84 HW	343	* with further packet processing */
f9e815b3 HW	344	up(&nfnl_sem);
	345	} while(nfnl && nfnl->sk_receive_queue.qlen);
	346	}
	347
395dde20	348	static void __exit nfnetlink_exit(void)
f9e815b3 HW	349	{
	350	printk("Removing netfilter NETLINK layer.\n");
	351	sock_release(nfnl->sk_socket);
	352	return;
	353	}
	354
395dde20	355	static int __init nfnetlink_init(void)
f9e815b3 HW	356	{
	357	printk("Netfilter messages via NETLINK v%s.\n", nfversion);
	358
06628607 PM	359	nfnl = netlink_kernel_create(NETLINK_NETFILTER, NFNLGRP_MAX,
06628607 PM	360	nfnetlink_rcv, THIS_MODULE);
f9e815b3 HW	361	if (!nfnl) {
	362	printk(KERN_ERR "cannot initialize nfnetlink!\n");
	363	return -1;
	364	}
	365
	366	return 0;
	367	}
	368
	369	module_init(nfnetlink_init);
	370	module_exit(nfnetlink_exit);
	371
	372	EXPORT_SYMBOL_GPL(nfnetlink_subsys_register);
	373	EXPORT_SYMBOL_GPL(nfnetlink_subsys_unregister);
	374	EXPORT_SYMBOL_GPL(nfnetlink_send);
	375	EXPORT_SYMBOL_GPL(nfnetlink_unicast);
	376	EXPORT_SYMBOL_GPL(nfattr_parse);
	377	EXPORT_SYMBOL_GPL(__nfa_fill);