[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/config.h>
#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 printk
#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);

	/* If the netlink socket wasn't created, then fail */
	if (!nfnl)
		return -1;

	nfnl_lock();
	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);
}

int 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->nfa_type;
		if (flavor && flavor <= maxattr)
			tb[flavor-1] = nfa;
		nfa = NFA_NEXT(nfa, len);
	}

	return 0;
}

/**
 * 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;

	memset(cda, 0, sizeof(struct nfattr *) * subsys->attr_count);

	/* check attribute lengths. */
	min_len = NLMSG_ALIGN(sizeof(struct nfgenmsg));
	if (nlh->nlmsg_len < min_len)
		return -EINVAL;

	if (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 = attr->nfa_type;
			if (flavor) {
				if (flavor > subsys->attr_count)
					return -EINVAL;
				cda[flavor - 1] = attr;
			}
			attr = NFA_NEXT(attr, attrlen);
		}
	} else
		return -EINVAL;

        return 0;
}

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

	NETLINK_CB(skb).dst_groups = 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 inline 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));

	/* 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_LENGTH(NLMSG_ALIGN(sizeof(struct nfgenmsg)))) {
		DEBUGP("received message was too short\n");
		return 0;
	}

	type = nlh->nlmsg_type;
	ss = nfnetlink_get_subsys(type);
	if (!ss)
		goto err_inval;

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

	if (nc->cap_required && 
	    !cap_raised(NETLINK_CB(skb).eff_cap, nc->cap_required)) {
		DEBUGP("permission denied for type %d\n", type);
		*errp = -EPERM;
		return -1;
	}

	{
		struct nfattr *cda[ss->attr_count];

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

		err = nc->call(nfnl, skb, nlh, cda, errp);
		*errp = err;
		return err;
	}

err_inval:
	*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);
		}

		up(&nfnl_sem);
	} while(nfnl && nfnl->sk_receive_queue.qlen);
}

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

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

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