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 struct lock_class_key nfnl_lockdep_keys[NFNL_SUBSYS_COUNT];
50
51 static const char *const nfnl_lockdep_names[NFNL_SUBSYS_COUNT] = {
52 [NFNL_SUBSYS_NONE] = "nfnl_subsys_none",
53 [NFNL_SUBSYS_CTNETLINK] = "nfnl_subsys_ctnetlink",
54 [NFNL_SUBSYS_CTNETLINK_EXP] = "nfnl_subsys_ctnetlink_exp",
55 [NFNL_SUBSYS_QUEUE] = "nfnl_subsys_queue",
56 [NFNL_SUBSYS_ULOG] = "nfnl_subsys_ulog",
57 [NFNL_SUBSYS_OSF] = "nfnl_subsys_osf",
58 [NFNL_SUBSYS_IPSET] = "nfnl_subsys_ipset",
59 [NFNL_SUBSYS_ACCT] = "nfnl_subsys_acct",
60 [NFNL_SUBSYS_CTNETLINK_TIMEOUT] = "nfnl_subsys_cttimeout",
61 [NFNL_SUBSYS_CTHELPER] = "nfnl_subsys_cthelper",
62 [NFNL_SUBSYS_NFTABLES] = "nfnl_subsys_nftables",
63 [NFNL_SUBSYS_NFT_COMPAT] = "nfnl_subsys_nftcompat",
64 };
65
66 static const int nfnl_group2type[NFNLGRP_MAX+1] = {
67 [NFNLGRP_CONNTRACK_NEW] = NFNL_SUBSYS_CTNETLINK,
68 [NFNLGRP_CONNTRACK_UPDATE] = NFNL_SUBSYS_CTNETLINK,
69 [NFNLGRP_CONNTRACK_DESTROY] = NFNL_SUBSYS_CTNETLINK,
70 [NFNLGRP_CONNTRACK_EXP_NEW] = NFNL_SUBSYS_CTNETLINK_EXP,
71 [NFNLGRP_CONNTRACK_EXP_UPDATE] = NFNL_SUBSYS_CTNETLINK_EXP,
72 [NFNLGRP_CONNTRACK_EXP_DESTROY] = NFNL_SUBSYS_CTNETLINK_EXP,
73 [NFNLGRP_NFTABLES] = NFNL_SUBSYS_NFTABLES,
74 [NFNLGRP_ACCT_QUOTA] = NFNL_SUBSYS_ACCT,
75 [NFNLGRP_NFTRACE] = NFNL_SUBSYS_NFTABLES,
76 };
77
nfnl_lock(__u8 subsys_id)78 void nfnl_lock(__u8 subsys_id)
79 {
80 mutex_lock(&table[subsys_id].mutex);
81 }
82 EXPORT_SYMBOL_GPL(nfnl_lock);
83
nfnl_unlock(__u8 subsys_id)84 void nfnl_unlock(__u8 subsys_id)
85 {
86 mutex_unlock(&table[subsys_id].mutex);
87 }
88 EXPORT_SYMBOL_GPL(nfnl_unlock);
89
90 #ifdef CONFIG_PROVE_LOCKING
lockdep_nfnl_is_held(u8 subsys_id)91 bool lockdep_nfnl_is_held(u8 subsys_id)
92 {
93 return lockdep_is_held(&table[subsys_id].mutex);
94 }
95 EXPORT_SYMBOL_GPL(lockdep_nfnl_is_held);
96 #endif
97
nfnetlink_subsys_register(const struct nfnetlink_subsystem * n)98 int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n)
99 {
100 u8 cb_id;
101
102 /* Sanity-check attr_count size to avoid stack buffer overflow. */
103 for (cb_id = 0; cb_id < n->cb_count; cb_id++)
104 if (WARN_ON(n->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT))
105 return -EINVAL;
106
107 nfnl_lock(n->subsys_id);
108 if (table[n->subsys_id].subsys) {
109 nfnl_unlock(n->subsys_id);
110 return -EBUSY;
111 }
112 rcu_assign_pointer(table[n->subsys_id].subsys, n);
113 nfnl_unlock(n->subsys_id);
114
115 return 0;
116 }
117 EXPORT_SYMBOL_GPL(nfnetlink_subsys_register);
118
nfnetlink_subsys_unregister(const struct nfnetlink_subsystem * n)119 int nfnetlink_subsys_unregister(const struct nfnetlink_subsystem *n)
120 {
121 nfnl_lock(n->subsys_id);
122 table[n->subsys_id].subsys = NULL;
123 nfnl_unlock(n->subsys_id);
124 synchronize_rcu();
125 return 0;
126 }
127 EXPORT_SYMBOL_GPL(nfnetlink_subsys_unregister);
128
nfnetlink_get_subsys(u16 type)129 static inline const struct nfnetlink_subsystem *nfnetlink_get_subsys(u16 type)
130 {
131 u8 subsys_id = NFNL_SUBSYS_ID(type);
132
133 if (subsys_id >= NFNL_SUBSYS_COUNT)
134 return NULL;
135
136 return rcu_dereference(table[subsys_id].subsys);
137 }
138
139 static inline const struct nfnl_callback *
nfnetlink_find_client(u16 type,const struct nfnetlink_subsystem * ss)140 nfnetlink_find_client(u16 type, const struct nfnetlink_subsystem *ss)
141 {
142 u8 cb_id = NFNL_MSG_TYPE(type);
143
144 if (cb_id >= ss->cb_count)
145 return NULL;
146
147 return &ss->cb[cb_id];
148 }
149
nfnetlink_has_listeners(struct net * net,unsigned int group)150 int nfnetlink_has_listeners(struct net *net, unsigned int group)
151 {
152 return netlink_has_listeners(net->nfnl, group);
153 }
154 EXPORT_SYMBOL_GPL(nfnetlink_has_listeners);
155
nfnetlink_send(struct sk_buff * skb,struct net * net,u32 portid,unsigned int group,int echo,gfp_t flags)156 int nfnetlink_send(struct sk_buff *skb, struct net *net, u32 portid,
157 unsigned int group, int echo, gfp_t flags)
158 {
159 return nlmsg_notify(net->nfnl, skb, portid, group, echo, flags);
160 }
161 EXPORT_SYMBOL_GPL(nfnetlink_send);
162
nfnetlink_set_err(struct net * net,u32 portid,u32 group,int error)163 int nfnetlink_set_err(struct net *net, u32 portid, u32 group, int error)
164 {
165 return netlink_set_err(net->nfnl, portid, group, error);
166 }
167 EXPORT_SYMBOL_GPL(nfnetlink_set_err);
168
nfnetlink_unicast(struct sk_buff * skb,struct net * net,u32 portid)169 int nfnetlink_unicast(struct sk_buff *skb, struct net *net, u32 portid)
170 {
171 int err;
172
173 err = nlmsg_unicast(net->nfnl, skb, portid);
174 if (err == -EAGAIN)
175 err = -ENOBUFS;
176
177 return err;
178 }
179 EXPORT_SYMBOL_GPL(nfnetlink_unicast);
180
181 /* Process one complete nfnetlink message. */
nfnetlink_rcv_msg(struct sk_buff * skb,struct nlmsghdr * nlh,struct netlink_ext_ack * extack)182 static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
183 struct netlink_ext_ack *extack)
184 {
185 struct net *net = sock_net(skb->sk);
186 const struct nfnl_callback *nc;
187 const struct nfnetlink_subsystem *ss;
188 int type, err;
189
190 /* All the messages must at least contain nfgenmsg */
191 if (nlmsg_len(nlh) < sizeof(struct nfgenmsg))
192 return 0;
193
194 type = nlh->nlmsg_type;
195 replay:
196 rcu_read_lock();
197 ss = nfnetlink_get_subsys(type);
198 if (!ss) {
199 #ifdef CONFIG_MODULES
200 rcu_read_unlock();
201 request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type));
202 rcu_read_lock();
203 ss = nfnetlink_get_subsys(type);
204 if (!ss)
205 #endif
206 {
207 rcu_read_unlock();
208 return -EINVAL;
209 }
210 }
211
212 nc = nfnetlink_find_client(type, ss);
213 if (!nc) {
214 rcu_read_unlock();
215 return -EINVAL;
216 }
217
218 {
219 int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
220 u8 cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
221 struct nlattr *cda[NFNL_MAX_ATTR_COUNT + 1];
222 struct nlattr *attr = (void *)nlh + min_len;
223 int attrlen = nlh->nlmsg_len - min_len;
224 __u8 subsys_id = NFNL_SUBSYS_ID(type);
225
226 /* Sanity-check NFNL_MAX_ATTR_COUNT */
227 if (ss->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT) {
228 rcu_read_unlock();
229 return -ENOMEM;
230 }
231
232 err = nla_parse_deprecated(cda, ss->cb[cb_id].attr_count,
233 attr, attrlen,
234 ss->cb[cb_id].policy, extack);
235 if (err < 0) {
236 rcu_read_unlock();
237 return err;
238 }
239
240 if (nc->call_rcu) {
241 err = nc->call_rcu(net, net->nfnl, skb, nlh,
242 (const struct nlattr **)cda,
243 extack);
244 rcu_read_unlock();
245 } else {
246 rcu_read_unlock();
247 nfnl_lock(subsys_id);
248 if (nfnl_dereference_protected(subsys_id) != ss ||
249 nfnetlink_find_client(type, ss) != nc)
250 err = -EAGAIN;
251 else if (nc->call)
252 err = nc->call(net, net->nfnl, skb, nlh,
253 (const struct nlattr **)cda,
254 extack);
255 else
256 err = -EINVAL;
257 nfnl_unlock(subsys_id);
258 }
259 if (err == -EAGAIN)
260 goto replay;
261 return err;
262 }
263 }
264
265 struct nfnl_err {
266 struct list_head head;
267 struct nlmsghdr *nlh;
268 int err;
269 struct netlink_ext_ack extack;
270 };
271
nfnl_err_add(struct list_head * list,struct nlmsghdr * nlh,int err,const struct netlink_ext_ack * extack)272 static int nfnl_err_add(struct list_head *list, struct nlmsghdr *nlh, int err,
273 const struct netlink_ext_ack *extack)
274 {
275 struct nfnl_err *nfnl_err;
276
277 nfnl_err = kmalloc(sizeof(struct nfnl_err), GFP_KERNEL);
278 if (nfnl_err == NULL)
279 return -ENOMEM;
280
281 nfnl_err->nlh = nlh;
282 nfnl_err->err = err;
283 nfnl_err->extack = *extack;
284 list_add_tail(&nfnl_err->head, list);
285
286 return 0;
287 }
288
nfnl_err_del(struct nfnl_err * nfnl_err)289 static void nfnl_err_del(struct nfnl_err *nfnl_err)
290 {
291 list_del(&nfnl_err->head);
292 kfree(nfnl_err);
293 }
294
nfnl_err_reset(struct list_head * err_list)295 static void nfnl_err_reset(struct list_head *err_list)
296 {
297 struct nfnl_err *nfnl_err, *next;
298
299 list_for_each_entry_safe(nfnl_err, next, err_list, head)
300 nfnl_err_del(nfnl_err);
301 }
302
nfnl_err_deliver(struct list_head * err_list,struct sk_buff * skb)303 static void nfnl_err_deliver(struct list_head *err_list, struct sk_buff *skb)
304 {
305 struct nfnl_err *nfnl_err, *next;
306
307 list_for_each_entry_safe(nfnl_err, next, err_list, head) {
308 netlink_ack(skb, nfnl_err->nlh, nfnl_err->err,
309 &nfnl_err->extack);
310 nfnl_err_del(nfnl_err);
311 }
312 }
313
314 enum {
315 NFNL_BATCH_FAILURE = (1 << 0),
316 NFNL_BATCH_DONE = (1 << 1),
317 NFNL_BATCH_REPLAY = (1 << 2),
318 };
319
nfnetlink_rcv_batch(struct sk_buff * skb,struct nlmsghdr * nlh,u16 subsys_id,u32 genid)320 static void nfnetlink_rcv_batch(struct sk_buff *skb, struct nlmsghdr *nlh,
321 u16 subsys_id, u32 genid)
322 {
323 struct sk_buff *oskb = skb;
324 struct net *net = sock_net(skb->sk);
325 const struct nfnetlink_subsystem *ss;
326 const struct nfnl_callback *nc;
327 struct netlink_ext_ack extack;
328 LIST_HEAD(err_list);
329 u32 status;
330 int err;
331
332 if (subsys_id >= NFNL_SUBSYS_COUNT)
333 return netlink_ack(skb, nlh, -EINVAL, NULL);
334 replay:
335 status = 0;
336 replay_abort:
337 skb = netlink_skb_clone(oskb, GFP_KERNEL);
338 if (!skb)
339 return netlink_ack(oskb, nlh, -ENOMEM, NULL);
340
341 nfnl_lock(subsys_id);
342 ss = nfnl_dereference_protected(subsys_id);
343 if (!ss) {
344 #ifdef CONFIG_MODULES
345 nfnl_unlock(subsys_id);
346 request_module("nfnetlink-subsys-%d", subsys_id);
347 nfnl_lock(subsys_id);
348 ss = nfnl_dereference_protected(subsys_id);
349 if (!ss)
350 #endif
351 {
352 nfnl_unlock(subsys_id);
353 netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL);
354 return kfree_skb(skb);
355 }
356 }
357
358 if (!ss->valid_genid || !ss->commit || !ss->abort) {
359 nfnl_unlock(subsys_id);
360 netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL);
361 return kfree_skb(skb);
362 }
363
364 if (!try_module_get(ss->owner)) {
365 nfnl_unlock(subsys_id);
366 netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL);
367 return kfree_skb(skb);
368 }
369
370 if (!ss->valid_genid(net, genid)) {
371 module_put(ss->owner);
372 nfnl_unlock(subsys_id);
373 netlink_ack(oskb, nlh, -ERESTART, NULL);
374 return kfree_skb(skb);
375 }
376
377 nfnl_unlock(subsys_id);
378
379 while (skb->len >= nlmsg_total_size(0)) {
380 int msglen, type;
381
382 if (fatal_signal_pending(current)) {
383 nfnl_err_reset(&err_list);
384 err = -EINTR;
385 status = NFNL_BATCH_FAILURE;
386 goto done;
387 }
388
389 memset(&extack, 0, sizeof(extack));
390 nlh = nlmsg_hdr(skb);
391 err = 0;
392
393 if (nlh->nlmsg_len < NLMSG_HDRLEN ||
394 skb->len < nlh->nlmsg_len ||
395 nlmsg_len(nlh) < sizeof(struct nfgenmsg)) {
396 nfnl_err_reset(&err_list);
397 status |= NFNL_BATCH_FAILURE;
398 goto done;
399 }
400
401 /* Only requests are handled by the kernel */
402 if (!(nlh->nlmsg_flags & NLM_F_REQUEST)) {
403 err = -EINVAL;
404 goto ack;
405 }
406
407 type = nlh->nlmsg_type;
408 if (type == NFNL_MSG_BATCH_BEGIN) {
409 /* Malformed: Batch begin twice */
410 nfnl_err_reset(&err_list);
411 status |= NFNL_BATCH_FAILURE;
412 goto done;
413 } else if (type == NFNL_MSG_BATCH_END) {
414 status |= NFNL_BATCH_DONE;
415 goto done;
416 } else if (type < NLMSG_MIN_TYPE) {
417 err = -EINVAL;
418 goto ack;
419 }
420
421 /* We only accept a batch with messages for the same
422 * subsystem.
423 */
424 if (NFNL_SUBSYS_ID(type) != subsys_id) {
425 err = -EINVAL;
426 goto ack;
427 }
428
429 nc = nfnetlink_find_client(type, ss);
430 if (!nc) {
431 err = -EINVAL;
432 goto ack;
433 }
434
435 {
436 int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
437 u8 cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
438 struct nlattr *cda[NFNL_MAX_ATTR_COUNT + 1];
439 struct nlattr *attr = (void *)nlh + min_len;
440 int attrlen = nlh->nlmsg_len - min_len;
441
442 /* Sanity-check NFTA_MAX_ATTR */
443 if (ss->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT) {
444 err = -ENOMEM;
445 goto ack;
446 }
447
448 err = nla_parse_deprecated(cda,
449 ss->cb[cb_id].attr_count,
450 attr, attrlen,
451 ss->cb[cb_id].policy, NULL);
452 if (err < 0)
453 goto ack;
454
455 if (nc->call_batch) {
456 err = nc->call_batch(net, net->nfnl, skb, nlh,
457 (const struct nlattr **)cda,
458 &extack);
459 }
460
461 /* The lock was released to autoload some module, we
462 * have to abort and start from scratch using the
463 * original skb.
464 */
465 if (err == -EAGAIN) {
466 status |= NFNL_BATCH_REPLAY;
467 goto done;
468 }
469 }
470 ack:
471 if (nlh->nlmsg_flags & NLM_F_ACK || err) {
472 /* Errors are delivered once the full batch has been
473 * processed, this avoids that the same error is
474 * reported several times when replaying the batch.
475 */
476 if (err == -ENOMEM ||
477 nfnl_err_add(&err_list, nlh, err, &extack) < 0) {
478 /* We failed to enqueue an error, reset the
479 * list of errors and send OOM to userspace
480 * pointing to the batch header.
481 */
482 nfnl_err_reset(&err_list);
483 netlink_ack(oskb, nlmsg_hdr(oskb), -ENOMEM,
484 NULL);
485 status |= NFNL_BATCH_FAILURE;
486 goto done;
487 }
488 /* We don't stop processing the batch on errors, thus,
489 * userspace gets all the errors that the batch
490 * triggers.
491 */
492 if (err)
493 status |= NFNL_BATCH_FAILURE;
494 }
495
496 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
497 if (msglen > skb->len)
498 msglen = skb->len;
499 skb_pull(skb, msglen);
500 }
501 done:
502 if (status & NFNL_BATCH_REPLAY) {
503 ss->abort(net, oskb, NFNL_ABORT_AUTOLOAD);
504 nfnl_err_reset(&err_list);
505 kfree_skb(skb);
506 module_put(ss->owner);
507 goto replay;
508 } else if (status == NFNL_BATCH_DONE) {
509 err = ss->commit(net, oskb);
510 if (err == -EAGAIN) {
511 status |= NFNL_BATCH_REPLAY;
512 goto done;
513 } else if (err) {
514 ss->abort(net, oskb, NFNL_ABORT_NONE);
515 netlink_ack(oskb, nlmsg_hdr(oskb), err, NULL);
516 }
517 } else {
518 enum nfnl_abort_action abort_action;
519
520 if (status & NFNL_BATCH_FAILURE)
521 abort_action = NFNL_ABORT_NONE;
522 else
523 abort_action = NFNL_ABORT_VALIDATE;
524
525 err = ss->abort(net, oskb, abort_action);
526 if (err == -EAGAIN) {
527 nfnl_err_reset(&err_list);
528 kfree_skb(skb);
529 module_put(ss->owner);
530 status |= NFNL_BATCH_FAILURE;
531 goto replay_abort;
532 }
533 }
534
535 nfnl_err_deliver(&err_list, oskb);
536 kfree_skb(skb);
537 module_put(ss->owner);
538 }
539
540 static const struct nla_policy nfnl_batch_policy[NFNL_BATCH_MAX + 1] = {
541 [NFNL_BATCH_GENID] = { .type = NLA_U32 },
542 };
543
nfnetlink_rcv_skb_batch(struct sk_buff * skb,struct nlmsghdr * nlh)544 static void nfnetlink_rcv_skb_batch(struct sk_buff *skb, struct nlmsghdr *nlh)
545 {
546 int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
547 struct nlattr *attr = (void *)nlh + min_len;
548 struct nlattr *cda[NFNL_BATCH_MAX + 1];
549 int attrlen = nlh->nlmsg_len - min_len;
550 struct nfgenmsg *nfgenmsg;
551 int msglen, err;
552 u32 gen_id = 0;
553 u16 res_id;
554
555 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
556 if (msglen > skb->len)
557 msglen = skb->len;
558
559 if (skb->len < NLMSG_HDRLEN + sizeof(struct nfgenmsg))
560 return;
561
562 err = nla_parse_deprecated(cda, NFNL_BATCH_MAX, attr, attrlen,
563 nfnl_batch_policy, NULL);
564 if (err < 0) {
565 netlink_ack(skb, nlh, err, NULL);
566 return;
567 }
568 if (cda[NFNL_BATCH_GENID])
569 gen_id = ntohl(nla_get_be32(cda[NFNL_BATCH_GENID]));
570
571 nfgenmsg = nlmsg_data(nlh);
572 skb_pull(skb, msglen);
573 /* Work around old nft using host byte order */
574 if (nfgenmsg->res_id == NFNL_SUBSYS_NFTABLES)
575 res_id = NFNL_SUBSYS_NFTABLES;
576 else
577 res_id = ntohs(nfgenmsg->res_id);
578
579 nfnetlink_rcv_batch(skb, nlh, res_id, gen_id);
580 }
581
nfnetlink_rcv(struct sk_buff * skb)582 static void nfnetlink_rcv(struct sk_buff *skb)
583 {
584 struct nlmsghdr *nlh = nlmsg_hdr(skb);
585
586 if (skb->len < NLMSG_HDRLEN ||
587 nlh->nlmsg_len < NLMSG_HDRLEN ||
588 skb->len < nlh->nlmsg_len)
589 return;
590
591 if (!netlink_net_capable(skb, CAP_NET_ADMIN)) {
592 netlink_ack(skb, nlh, -EPERM, NULL);
593 return;
594 }
595
596 if (nlh->nlmsg_type == NFNL_MSG_BATCH_BEGIN)
597 nfnetlink_rcv_skb_batch(skb, nlh);
598 else
599 netlink_rcv_skb(skb, nfnetlink_rcv_msg);
600 }
601
602 #ifdef CONFIG_MODULES
nfnetlink_bind(struct net * net,int group)603 static int nfnetlink_bind(struct net *net, int group)
604 {
605 const struct nfnetlink_subsystem *ss;
606 int type;
607
608 if (group <= NFNLGRP_NONE || group > NFNLGRP_MAX)
609 return 0;
610
611 type = nfnl_group2type[group];
612
613 rcu_read_lock();
614 ss = nfnetlink_get_subsys(type << 8);
615 rcu_read_unlock();
616 if (!ss)
617 request_module_nowait("nfnetlink-subsys-%d", type);
618 return 0;
619 }
620 #endif
621
nfnetlink_net_init(struct net * net)622 static int __net_init nfnetlink_net_init(struct net *net)
623 {
624 struct sock *nfnl;
625 struct netlink_kernel_cfg cfg = {
626 .groups = NFNLGRP_MAX,
627 .input = nfnetlink_rcv,
628 #ifdef CONFIG_MODULES
629 .bind = nfnetlink_bind,
630 #endif
631 };
632
633 nfnl = netlink_kernel_create(net, NETLINK_NETFILTER, &cfg);
634 if (!nfnl)
635 return -ENOMEM;
636 net->nfnl_stash = nfnl;
637 rcu_assign_pointer(net->nfnl, nfnl);
638 return 0;
639 }
640
nfnetlink_net_exit_batch(struct list_head * net_exit_list)641 static void __net_exit nfnetlink_net_exit_batch(struct list_head *net_exit_list)
642 {
643 struct net *net;
644
645 list_for_each_entry(net, net_exit_list, exit_list)
646 RCU_INIT_POINTER(net->nfnl, NULL);
647 synchronize_net();
648 list_for_each_entry(net, net_exit_list, exit_list)
649 netlink_kernel_release(net->nfnl_stash);
650 }
651
652 static struct pernet_operations nfnetlink_net_ops = {
653 .init = nfnetlink_net_init,
654 .exit_batch = nfnetlink_net_exit_batch,
655 };
656
nfnetlink_init(void)657 static int __init nfnetlink_init(void)
658 {
659 int i;
660
661 for (i = NFNLGRP_NONE + 1; i <= NFNLGRP_MAX; i++)
662 BUG_ON(nfnl_group2type[i] == NFNL_SUBSYS_NONE);
663
664 for (i=0; i<NFNL_SUBSYS_COUNT; i++)
665 __mutex_init(&table[i].mutex, nfnl_lockdep_names[i], &nfnl_lockdep_keys[i]);
666
667 return register_pernet_subsys(&nfnetlink_net_ops);
668 }
669
nfnetlink_exit(void)670 static void __exit nfnetlink_exit(void)
671 {
672 unregister_pernet_subsys(&nfnetlink_net_ops);
673 }
674 module_init(nfnetlink_init);
675 module_exit(nfnetlink_exit);
676