[mirror_ubuntu-artful-kernel.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");

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);
}

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