xref: /openbmc/linux/net/netfilter/nfnetlink.c (revision e7bae9bb) 
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) 2005-2017 by Pablo Neira Ayuso <pablo@netfilter.org>
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/module.h>
18 #include <linux/types.h>
19 #include <linux/socket.h>
20 #include <linux/kernel.h>
21 #include <linux/string.h>
22 #include <linux/sockios.h>
23 #include <linux/net.h>
24 #include <linux/skbuff.h>
25 #include <linux/uaccess.h>
26 #include <net/sock.h>
27 #include <linux/init.h>
28 #include <linux/sched/signal.h>
29 
30 #include <net/netlink.h>
31 #include <linux/netfilter/nfnetlink.h>
32 
33 MODULE_LICENSE("GPL");
34 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
35 MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NETFILTER);
36 MODULE_DESCRIPTION("Netfilter messages via netlink socket");
37 
38 #define nfnl_dereference_protected(id) \
39 	rcu_dereference_protected(table[(id)].subsys, \
40 				  lockdep_nfnl_is_held((id)))
41 
42 #define NFNL_MAX_ATTR_COUNT	32
43 
44 static struct {
45 	struct mutex				mutex;
46 	const struct nfnetlink_subsystem __rcu	*subsys;
47 } table[NFNL_SUBSYS_COUNT];
48 
49 static const int nfnl_group2type[NFNLGRP_MAX+1] = {
50 	[NFNLGRP_CONNTRACK_NEW]		= NFNL_SUBSYS_CTNETLINK,
51 	[NFNLGRP_CONNTRACK_UPDATE]	= NFNL_SUBSYS_CTNETLINK,
52 	[NFNLGRP_CONNTRACK_DESTROY]	= NFNL_SUBSYS_CTNETLINK,
53 	[NFNLGRP_CONNTRACK_EXP_NEW]	= NFNL_SUBSYS_CTNETLINK_EXP,
54 	[NFNLGRP_CONNTRACK_EXP_UPDATE]	= NFNL_SUBSYS_CTNETLINK_EXP,
55 	[NFNLGRP_CONNTRACK_EXP_DESTROY] = NFNL_SUBSYS_CTNETLINK_EXP,
56 	[NFNLGRP_NFTABLES]		= NFNL_SUBSYS_NFTABLES,
57 	[NFNLGRP_ACCT_QUOTA]		= NFNL_SUBSYS_ACCT,
58 	[NFNLGRP_NFTRACE]		= NFNL_SUBSYS_NFTABLES,
59 };
60 
61 void nfnl_lock(__u8 subsys_id)
62 {
63 	mutex_lock(&table[subsys_id].mutex);
64 }
65 EXPORT_SYMBOL_GPL(nfnl_lock);
66 
67 void nfnl_unlock(__u8 subsys_id)
68 {
69 	mutex_unlock(&table[subsys_id].mutex);
70 }
71 EXPORT_SYMBOL_GPL(nfnl_unlock);
72 
73 #ifdef CONFIG_PROVE_LOCKING
74 bool lockdep_nfnl_is_held(u8 subsys_id)
75 {
76 	return lockdep_is_held(&table[subsys_id].mutex);
77 }
78 EXPORT_SYMBOL_GPL(lockdep_nfnl_is_held);
79 #endif
80 
81 int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n)
82 {
83 	u8 cb_id;
84 
85 	/* Sanity-check attr_count size to avoid stack buffer overflow. */
86 	for (cb_id = 0; cb_id < n->cb_count; cb_id++)
87 		if (WARN_ON(n->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT))
88 			return -EINVAL;
89 
90 	nfnl_lock(n->subsys_id);
91 	if (table[n->subsys_id].subsys) {
92 		nfnl_unlock(n->subsys_id);
93 		return -EBUSY;
94 	}
95 	rcu_assign_pointer(table[n->subsys_id].subsys, n);
96 	nfnl_unlock(n->subsys_id);
97 
98 	return 0;
99 }
100 EXPORT_SYMBOL_GPL(nfnetlink_subsys_register);
101 
102 int nfnetlink_subsys_unregister(const struct nfnetlink_subsystem *n)
103 {
104 	nfnl_lock(n->subsys_id);
105 	table[n->subsys_id].subsys = NULL;
106 	nfnl_unlock(n->subsys_id);
107 	synchronize_rcu();
108 	return 0;
109 }
110 EXPORT_SYMBOL_GPL(nfnetlink_subsys_unregister);
111 
112 static inline const struct nfnetlink_subsystem *nfnetlink_get_subsys(u16 type)
113 {
114 	u8 subsys_id = NFNL_SUBSYS_ID(type);
115 
116 	if (subsys_id >= NFNL_SUBSYS_COUNT)
117 		return NULL;
118 
119 	return rcu_dereference(table[subsys_id].subsys);
120 }
121 
122 static inline const struct nfnl_callback *
123 nfnetlink_find_client(u16 type, const struct nfnetlink_subsystem *ss)
124 {
125 	u8 cb_id = NFNL_MSG_TYPE(type);
126 
127 	if (cb_id >= ss->cb_count)
128 		return NULL;
129 
130 	return &ss->cb[cb_id];
131 }
132 
133 int nfnetlink_has_listeners(struct net *net, unsigned int group)
134 {
135 	return netlink_has_listeners(net->nfnl, group);
136 }
137 EXPORT_SYMBOL_GPL(nfnetlink_has_listeners);
138 
139 int nfnetlink_send(struct sk_buff *skb, struct net *net, u32 portid,
140 		   unsigned int group, int echo, gfp_t flags)
141 {
142 	return nlmsg_notify(net->nfnl, skb, portid, group, echo, flags);
143 }
144 EXPORT_SYMBOL_GPL(nfnetlink_send);
145 
146 int nfnetlink_set_err(struct net *net, u32 portid, u32 group, int error)
147 {
148 	return netlink_set_err(net->nfnl, portid, group, error);
149 }
150 EXPORT_SYMBOL_GPL(nfnetlink_set_err);
151 
152 int nfnetlink_unicast(struct sk_buff *skb, struct net *net, u32 portid)
153 {
154 	int err;
155 
156 	err = nlmsg_unicast(net->nfnl, skb, portid);
157 	if (err == -EAGAIN)
158 		err = -ENOBUFS;
159 
160 	return err;
161 }
162 EXPORT_SYMBOL_GPL(nfnetlink_unicast);
163 
164 /* Process one complete nfnetlink message. */
165 static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
166 			     struct netlink_ext_ack *extack)
167 {
168 	struct net *net = sock_net(skb->sk);
169 	const struct nfnl_callback *nc;
170 	const struct nfnetlink_subsystem *ss;
171 	int type, err;
172 
173 	/* All the messages must at least contain nfgenmsg */
174 	if (nlmsg_len(nlh) < sizeof(struct nfgenmsg))
175 		return 0;
176 
177 	type = nlh->nlmsg_type;
178 replay:
179 	rcu_read_lock();
180 	ss = nfnetlink_get_subsys(type);
181 	if (!ss) {
182 #ifdef CONFIG_MODULES
183 		rcu_read_unlock();
184 		request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type));
185 		rcu_read_lock();
186 		ss = nfnetlink_get_subsys(type);
187 		if (!ss)
188 #endif
189 		{
190 			rcu_read_unlock();
191 			return -EINVAL;
192 		}
193 	}
194 
195 	nc = nfnetlink_find_client(type, ss);
196 	if (!nc) {
197 		rcu_read_unlock();
198 		return -EINVAL;
199 	}
200 
201 	{
202 		int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
203 		u8 cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
204 		struct nlattr *cda[NFNL_MAX_ATTR_COUNT + 1];
205 		struct nlattr *attr = (void *)nlh + min_len;
206 		int attrlen = nlh->nlmsg_len - min_len;
207 		__u8 subsys_id = NFNL_SUBSYS_ID(type);
208 
209 		/* Sanity-check NFNL_MAX_ATTR_COUNT */
210 		if (ss->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT) {
211 			rcu_read_unlock();
212 			return -ENOMEM;
213 		}
214 
215 		err = nla_parse_deprecated(cda, ss->cb[cb_id].attr_count,
216 					   attr, attrlen,
217 					   ss->cb[cb_id].policy, extack);
218 		if (err < 0) {
219 			rcu_read_unlock();
220 			return err;
221 		}
222 
223 		if (nc->call_rcu) {
224 			err = nc->call_rcu(net, net->nfnl, skb, nlh,
225 					   (const struct nlattr **)cda,
226 					   extack);
227 			rcu_read_unlock();
228 		} else {
229 			rcu_read_unlock();
230 			nfnl_lock(subsys_id);
231 			if (nfnl_dereference_protected(subsys_id) != ss ||
232 			    nfnetlink_find_client(type, ss) != nc)
233 				err = -EAGAIN;
234 			else if (nc->call)
235 				err = nc->call(net, net->nfnl, skb, nlh,
236 					       (const struct nlattr **)cda,
237 					       extack);
238 			else
239 				err = -EINVAL;
240 			nfnl_unlock(subsys_id);
241 		}
242 		if (err == -EAGAIN)
243 			goto replay;
244 		return err;
245 	}
246 }
247 
248 struct nfnl_err {
249 	struct list_head	head;
250 	struct nlmsghdr		*nlh;
251 	int			err;
252 	struct netlink_ext_ack	extack;
253 };
254 
255 static int nfnl_err_add(struct list_head *list, struct nlmsghdr *nlh, int err,
256 			const struct netlink_ext_ack *extack)
257 {
258 	struct nfnl_err *nfnl_err;
259 
260 	nfnl_err = kmalloc(sizeof(struct nfnl_err), GFP_KERNEL);
261 	if (nfnl_err == NULL)
262 		return -ENOMEM;
263 
264 	nfnl_err->nlh = nlh;
265 	nfnl_err->err = err;
266 	nfnl_err->extack = *extack;
267 	list_add_tail(&nfnl_err->head, list);
268 
269 	return 0;
270 }
271 
272 static void nfnl_err_del(struct nfnl_err *nfnl_err)
273 {
274 	list_del(&nfnl_err->head);
275 	kfree(nfnl_err);
276 }
277 
278 static void nfnl_err_reset(struct list_head *err_list)
279 {
280 	struct nfnl_err *nfnl_err, *next;
281 
282 	list_for_each_entry_safe(nfnl_err, next, err_list, head)
283 		nfnl_err_del(nfnl_err);
284 }
285 
286 static void nfnl_err_deliver(struct list_head *err_list, struct sk_buff *skb)
287 {
288 	struct nfnl_err *nfnl_err, *next;
289 
290 	list_for_each_entry_safe(nfnl_err, next, err_list, head) {
291 		netlink_ack(skb, nfnl_err->nlh, nfnl_err->err,
292 			    &nfnl_err->extack);
293 		nfnl_err_del(nfnl_err);
294 	}
295 }
296 
297 enum {
298 	NFNL_BATCH_FAILURE	= (1 << 0),
299 	NFNL_BATCH_DONE		= (1 << 1),
300 	NFNL_BATCH_REPLAY	= (1 << 2),
301 };
302 
303 static void nfnetlink_rcv_batch(struct sk_buff *skb, struct nlmsghdr *nlh,
304 				u16 subsys_id, u32 genid)
305 {
306 	struct sk_buff *oskb = skb;
307 	struct net *net = sock_net(skb->sk);
308 	const struct nfnetlink_subsystem *ss;
309 	const struct nfnl_callback *nc;
310 	struct netlink_ext_ack extack;
311 	LIST_HEAD(err_list);
312 	u32 status;
313 	int err;
314 
315 	if (subsys_id >= NFNL_SUBSYS_COUNT)
316 		return netlink_ack(skb, nlh, -EINVAL, NULL);
317 replay:
318 	status = 0;
319 
320 	skb = netlink_skb_clone(oskb, GFP_KERNEL);
321 	if (!skb)
322 		return netlink_ack(oskb, nlh, -ENOMEM, NULL);
323 
324 	nfnl_lock(subsys_id);
325 	ss = nfnl_dereference_protected(subsys_id);
326 	if (!ss) {
327 #ifdef CONFIG_MODULES
328 		nfnl_unlock(subsys_id);
329 		request_module("nfnetlink-subsys-%d", subsys_id);
330 		nfnl_lock(subsys_id);
331 		ss = nfnl_dereference_protected(subsys_id);
332 		if (!ss)
333 #endif
334 		{
335 			nfnl_unlock(subsys_id);
336 			netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL);
337 			return kfree_skb(skb);
338 		}
339 	}
340 
341 	if (!ss->valid_genid || !ss->commit || !ss->abort) {
342 		nfnl_unlock(subsys_id);
343 		netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL);
344 		return kfree_skb(skb);
345 	}
346 
347 	if (!try_module_get(ss->owner)) {
348 		nfnl_unlock(subsys_id);
349 		netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL);
350 		return kfree_skb(skb);
351 	}
352 
353 	if (!ss->valid_genid(net, genid)) {
354 		module_put(ss->owner);
355 		nfnl_unlock(subsys_id);
356 		netlink_ack(oskb, nlh, -ERESTART, NULL);
357 		return kfree_skb(skb);
358 	}
359 
360 	nfnl_unlock(subsys_id);
361 
362 	while (skb->len >= nlmsg_total_size(0)) {
363 		int msglen, type;
364 
365 		if (fatal_signal_pending(current)) {
366 			nfnl_err_reset(&err_list);
367 			err = -EINTR;
368 			status = NFNL_BATCH_FAILURE;
369 			goto done;
370 		}
371 
372 		memset(&extack, 0, sizeof(extack));
373 		nlh = nlmsg_hdr(skb);
374 		err = 0;
375 
376 		if (nlh->nlmsg_len < NLMSG_HDRLEN ||
377 		    skb->len < nlh->nlmsg_len ||
378 		    nlmsg_len(nlh) < sizeof(struct nfgenmsg)) {
379 			nfnl_err_reset(&err_list);
380 			status |= NFNL_BATCH_FAILURE;
381 			goto done;
382 		}
383 
384 		/* Only requests are handled by the kernel */
385 		if (!(nlh->nlmsg_flags & NLM_F_REQUEST)) {
386 			err = -EINVAL;
387 			goto ack;
388 		}
389 
390 		type = nlh->nlmsg_type;
391 		if (type == NFNL_MSG_BATCH_BEGIN) {
392 			/* Malformed: Batch begin twice */
393 			nfnl_err_reset(&err_list);
394 			status |= NFNL_BATCH_FAILURE;
395 			goto done;
396 		} else if (type == NFNL_MSG_BATCH_END) {
397 			status |= NFNL_BATCH_DONE;
398 			goto done;
399 		} else if (type < NLMSG_MIN_TYPE) {
400 			err = -EINVAL;
401 			goto ack;
402 		}
403 
404 		/* We only accept a batch with messages for the same
405 		 * subsystem.
406 		 */
407 		if (NFNL_SUBSYS_ID(type) != subsys_id) {
408 			err = -EINVAL;
409 			goto ack;
410 		}
411 
412 		nc = nfnetlink_find_client(type, ss);
413 		if (!nc) {
414 			err = -EINVAL;
415 			goto ack;
416 		}
417 
418 		{
419 			int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
420 			u8 cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
421 			struct nlattr *cda[NFNL_MAX_ATTR_COUNT + 1];
422 			struct nlattr *attr = (void *)nlh + min_len;
423 			int attrlen = nlh->nlmsg_len - min_len;
424 
425 			/* Sanity-check NFTA_MAX_ATTR */
426 			if (ss->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT) {
427 				err = -ENOMEM;
428 				goto ack;
429 			}
430 
431 			err = nla_parse_deprecated(cda,
432 						   ss->cb[cb_id].attr_count,
433 						   attr, attrlen,
434 						   ss->cb[cb_id].policy, NULL);
435 			if (err < 0)
436 				goto ack;
437 
438 			if (nc->call_batch) {
439 				err = nc->call_batch(net, net->nfnl, skb, nlh,
440 						     (const struct nlattr **)cda,
441 						     &extack);
442 			}
443 
444 			/* The lock was released to autoload some module, we
445 			 * have to abort and start from scratch using the
446 			 * original skb.
447 			 */
448 			if (err == -EAGAIN) {
449 				status |= NFNL_BATCH_REPLAY;
450 				goto done;
451 			}
452 		}
453 ack:
454 		if (nlh->nlmsg_flags & NLM_F_ACK || err) {
455 			/* Errors are delivered once the full batch has been
456 			 * processed, this avoids that the same error is
457 			 * reported several times when replaying the batch.
458 			 */
459 			if (nfnl_err_add(&err_list, nlh, err, &extack) < 0) {
460 				/* We failed to enqueue an error, reset the
461 				 * list of errors and send OOM to userspace
462 				 * pointing to the batch header.
463 				 */
464 				nfnl_err_reset(&err_list);
465 				netlink_ack(oskb, nlmsg_hdr(oskb), -ENOMEM,
466 					    NULL);
467 				status |= NFNL_BATCH_FAILURE;
468 				goto done;
469 			}
470 			/* We don't stop processing the batch on errors, thus,
471 			 * userspace gets all the errors that the batch
472 			 * triggers.
473 			 */
474 			if (err)
475 				status |= NFNL_BATCH_FAILURE;
476 		}
477 
478 		msglen = NLMSG_ALIGN(nlh->nlmsg_len);
479 		if (msglen > skb->len)
480 			msglen = skb->len;
481 		skb_pull(skb, msglen);
482 	}
483 done:
484 	if (status & NFNL_BATCH_REPLAY) {
485 		ss->abort(net, oskb, true);
486 		nfnl_err_reset(&err_list);
487 		kfree_skb(skb);
488 		module_put(ss->owner);
489 		goto replay;
490 	} else if (status == NFNL_BATCH_DONE) {
491 		err = ss->commit(net, oskb);
492 		if (err == -EAGAIN) {
493 			status |= NFNL_BATCH_REPLAY;
494 			goto done;
495 		} else if (err) {
496 			ss->abort(net, oskb, false);
497 			netlink_ack(oskb, nlmsg_hdr(oskb), err, NULL);
498 		}
499 	} else {
500 		ss->abort(net, oskb, false);
501 	}
502 	if (ss->cleanup)
503 		ss->cleanup(net);
504 
505 	nfnl_err_deliver(&err_list, oskb);
506 	kfree_skb(skb);
507 	module_put(ss->owner);
508 }
509 
510 static const struct nla_policy nfnl_batch_policy[NFNL_BATCH_MAX + 1] = {
511 	[NFNL_BATCH_GENID]	= { .type = NLA_U32 },
512 };
513 
514 static void nfnetlink_rcv_skb_batch(struct sk_buff *skb, struct nlmsghdr *nlh)
515 {
516 	int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
517 	struct nlattr *attr = (void *)nlh + min_len;
518 	struct nlattr *cda[NFNL_BATCH_MAX + 1];
519 	int attrlen = nlh->nlmsg_len - min_len;
520 	struct nfgenmsg *nfgenmsg;
521 	int msglen, err;
522 	u32 gen_id = 0;
523 	u16 res_id;
524 
525 	msglen = NLMSG_ALIGN(nlh->nlmsg_len);
526 	if (msglen > skb->len)
527 		msglen = skb->len;
528 
529 	if (skb->len < NLMSG_HDRLEN + sizeof(struct nfgenmsg))
530 		return;
531 
532 	err = nla_parse_deprecated(cda, NFNL_BATCH_MAX, attr, attrlen,
533 				   nfnl_batch_policy, NULL);
534 	if (err < 0) {
535 		netlink_ack(skb, nlh, err, NULL);
536 		return;
537 	}
538 	if (cda[NFNL_BATCH_GENID])
539 		gen_id = ntohl(nla_get_be32(cda[NFNL_BATCH_GENID]));
540 
541 	nfgenmsg = nlmsg_data(nlh);
542 	skb_pull(skb, msglen);
543 	/* Work around old nft using host byte order */
544 	if (nfgenmsg->res_id == NFNL_SUBSYS_NFTABLES)
545 		res_id = NFNL_SUBSYS_NFTABLES;
546 	else
547 		res_id = ntohs(nfgenmsg->res_id);
548 
549 	nfnetlink_rcv_batch(skb, nlh, res_id, gen_id);
550 }
551 
552 static void nfnetlink_rcv(struct sk_buff *skb)
553 {
554 	struct nlmsghdr *nlh = nlmsg_hdr(skb);
555 
556 	if (skb->len < NLMSG_HDRLEN ||
557 	    nlh->nlmsg_len < NLMSG_HDRLEN ||
558 	    skb->len < nlh->nlmsg_len)
559 		return;
560 
561 	if (!netlink_net_capable(skb, CAP_NET_ADMIN)) {
562 		netlink_ack(skb, nlh, -EPERM, NULL);
563 		return;
564 	}
565 
566 	if (nlh->nlmsg_type == NFNL_MSG_BATCH_BEGIN)
567 		nfnetlink_rcv_skb_batch(skb, nlh);
568 	else
569 		netlink_rcv_skb(skb, nfnetlink_rcv_msg);
570 }
571 
572 #ifdef CONFIG_MODULES
573 static int nfnetlink_bind(struct net *net, int group)
574 {
575 	const struct nfnetlink_subsystem *ss;
576 	int type;
577 
578 	if (group <= NFNLGRP_NONE || group > NFNLGRP_MAX)
579 		return 0;
580 
581 	type = nfnl_group2type[group];
582 
583 	rcu_read_lock();
584 	ss = nfnetlink_get_subsys(type << 8);
585 	rcu_read_unlock();
586 	if (!ss)
587 		request_module_nowait("nfnetlink-subsys-%d", type);
588 	return 0;
589 }
590 #endif
591 
592 static int __net_init nfnetlink_net_init(struct net *net)
593 {
594 	struct sock *nfnl;
595 	struct netlink_kernel_cfg cfg = {
596 		.groups	= NFNLGRP_MAX,
597 		.input	= nfnetlink_rcv,
598 #ifdef CONFIG_MODULES
599 		.bind	= nfnetlink_bind,
600 #endif
601 	};
602 
603 	nfnl = netlink_kernel_create(net, NETLINK_NETFILTER, &cfg);
604 	if (!nfnl)
605 		return -ENOMEM;
606 	net->nfnl_stash = nfnl;
607 	rcu_assign_pointer(net->nfnl, nfnl);
608 	return 0;
609 }
610 
611 static void __net_exit nfnetlink_net_exit_batch(struct list_head *net_exit_list)
612 {
613 	struct net *net;
614 
615 	list_for_each_entry(net, net_exit_list, exit_list)
616 		RCU_INIT_POINTER(net->nfnl, NULL);
617 	synchronize_net();
618 	list_for_each_entry(net, net_exit_list, exit_list)
619 		netlink_kernel_release(net->nfnl_stash);
620 }
621 
622 static struct pernet_operations nfnetlink_net_ops = {
623 	.init		= nfnetlink_net_init,
624 	.exit_batch	= nfnetlink_net_exit_batch,
625 };
626 
627 static int __init nfnetlink_init(void)
628 {
629 	int i;
630 
631 	for (i = NFNLGRP_NONE + 1; i <= NFNLGRP_MAX; i++)
632 		BUG_ON(nfnl_group2type[i] == NFNL_SUBSYS_NONE);
633 
634 	for (i=0; i<NFNL_SUBSYS_COUNT; i++)
635 		mutex_init(&table[i].mutex);
636 
637 	return register_pernet_subsys(&nfnetlink_net_ops);
638 }
639 
640 static void __exit nfnetlink_exit(void)
641 {
642 	unregister_pernet_subsys(&nfnetlink_net_ops);
643 }
644 module_init(nfnetlink_init);
645 module_exit(nfnetlink_exit);
646