Loading...
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * NETLINK Generic Netlink Family
4 *
5 * Authors: Jamal Hadi Salim
6 * Thomas Graf <tgraf@suug.ch>
7 * Johannes Berg <johannes@sipsolutions.net>
8 */
9
10#include <linux/module.h>
11#include <linux/kernel.h>
12#include <linux/slab.h>
13#include <linux/errno.h>
14#include <linux/types.h>
15#include <linux/socket.h>
16#include <linux/string.h>
17#include <linux/skbuff.h>
18#include <linux/mutex.h>
19#include <linux/bitmap.h>
20#include <linux/rwsem.h>
21#include <linux/idr.h>
22#include <net/sock.h>
23#include <net/genetlink.h>
24
25static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */
26static DECLARE_RWSEM(cb_lock);
27
28atomic_t genl_sk_destructing_cnt = ATOMIC_INIT(0);
29DECLARE_WAIT_QUEUE_HEAD(genl_sk_destructing_waitq);
30
31void genl_lock(void)
32{
33 mutex_lock(&genl_mutex);
34}
35EXPORT_SYMBOL(genl_lock);
36
37void genl_unlock(void)
38{
39 mutex_unlock(&genl_mutex);
40}
41EXPORT_SYMBOL(genl_unlock);
42
43#ifdef CONFIG_LOCKDEP
44bool lockdep_genl_is_held(void)
45{
46 return lockdep_is_held(&genl_mutex);
47}
48EXPORT_SYMBOL(lockdep_genl_is_held);
49#endif
50
51static void genl_lock_all(void)
52{
53 down_write(&cb_lock);
54 genl_lock();
55}
56
57static void genl_unlock_all(void)
58{
59 genl_unlock();
60 up_write(&cb_lock);
61}
62
63static DEFINE_IDR(genl_fam_idr);
64
65/*
66 * Bitmap of multicast groups that are currently in use.
67 *
68 * To avoid an allocation at boot of just one unsigned long,
69 * declare it global instead.
70 * Bit 0 is marked as already used since group 0 is invalid.
71 * Bit 1 is marked as already used since the drop-monitor code
72 * abuses the API and thinks it can statically use group 1.
73 * That group will typically conflict with other groups that
74 * any proper users use.
75 * Bit 16 is marked as used since it's used for generic netlink
76 * and the code no longer marks pre-reserved IDs as used.
77 * Bit 17 is marked as already used since the VFS quota code
78 * also abused this API and relied on family == group ID, we
79 * cater to that by giving it a static family and group ID.
80 * Bit 18 is marked as already used since the PMCRAID driver
81 * did the same thing as the VFS quota code (maybe copied?)
82 */
83static unsigned long mc_group_start = 0x3 | BIT(GENL_ID_CTRL) |
84 BIT(GENL_ID_VFS_DQUOT) |
85 BIT(GENL_ID_PMCRAID);
86static unsigned long *mc_groups = &mc_group_start;
87static unsigned long mc_groups_longs = 1;
88
89static int genl_ctrl_event(int event, const struct genl_family *family,
90 const struct genl_multicast_group *grp,
91 int grp_id);
92
93static const struct genl_family *genl_family_find_byid(unsigned int id)
94{
95 return idr_find(&genl_fam_idr, id);
96}
97
98static const struct genl_family *genl_family_find_byname(char *name)
99{
100 const struct genl_family *family;
101 unsigned int id;
102
103 idr_for_each_entry(&genl_fam_idr, family, id)
104 if (strcmp(family->name, name) == 0)
105 return family;
106
107 return NULL;
108}
109
110static const struct genl_ops *genl_get_cmd(u8 cmd,
111 const struct genl_family *family)
112{
113 int i;
114
115 for (i = 0; i < family->n_ops; i++)
116 if (family->ops[i].cmd == cmd)
117 return &family->ops[i];
118
119 return NULL;
120}
121
122static int genl_allocate_reserve_groups(int n_groups, int *first_id)
123{
124 unsigned long *new_groups;
125 int start = 0;
126 int i;
127 int id;
128 bool fits;
129
130 do {
131 if (start == 0)
132 id = find_first_zero_bit(mc_groups,
133 mc_groups_longs *
134 BITS_PER_LONG);
135 else
136 id = find_next_zero_bit(mc_groups,
137 mc_groups_longs * BITS_PER_LONG,
138 start);
139
140 fits = true;
141 for (i = id;
142 i < min_t(int, id + n_groups,
143 mc_groups_longs * BITS_PER_LONG);
144 i++) {
145 if (test_bit(i, mc_groups)) {
146 start = i;
147 fits = false;
148 break;
149 }
150 }
151
152 if (id + n_groups > mc_groups_longs * BITS_PER_LONG) {
153 unsigned long new_longs = mc_groups_longs +
154 BITS_TO_LONGS(n_groups);
155 size_t nlen = new_longs * sizeof(unsigned long);
156
157 if (mc_groups == &mc_group_start) {
158 new_groups = kzalloc(nlen, GFP_KERNEL);
159 if (!new_groups)
160 return -ENOMEM;
161 mc_groups = new_groups;
162 *mc_groups = mc_group_start;
163 } else {
164 new_groups = krealloc(mc_groups, nlen,
165 GFP_KERNEL);
166 if (!new_groups)
167 return -ENOMEM;
168 mc_groups = new_groups;
169 for (i = 0; i < BITS_TO_LONGS(n_groups); i++)
170 mc_groups[mc_groups_longs + i] = 0;
171 }
172 mc_groups_longs = new_longs;
173 }
174 } while (!fits);
175
176 for (i = id; i < id + n_groups; i++)
177 set_bit(i, mc_groups);
178 *first_id = id;
179 return 0;
180}
181
182static struct genl_family genl_ctrl;
183
184static int genl_validate_assign_mc_groups(struct genl_family *family)
185{
186 int first_id;
187 int n_groups = family->n_mcgrps;
188 int err = 0, i;
189 bool groups_allocated = false;
190
191 if (!n_groups)
192 return 0;
193
194 for (i = 0; i < n_groups; i++) {
195 const struct genl_multicast_group *grp = &family->mcgrps[i];
196
197 if (WARN_ON(grp->name[0] == '\0'))
198 return -EINVAL;
199 if (WARN_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL))
200 return -EINVAL;
201 }
202
203 /* special-case our own group and hacks */
204 if (family == &genl_ctrl) {
205 first_id = GENL_ID_CTRL;
206 BUG_ON(n_groups != 1);
207 } else if (strcmp(family->name, "NET_DM") == 0) {
208 first_id = 1;
209 BUG_ON(n_groups != 1);
210 } else if (family->id == GENL_ID_VFS_DQUOT) {
211 first_id = GENL_ID_VFS_DQUOT;
212 BUG_ON(n_groups != 1);
213 } else if (family->id == GENL_ID_PMCRAID) {
214 first_id = GENL_ID_PMCRAID;
215 BUG_ON(n_groups != 1);
216 } else {
217 groups_allocated = true;
218 err = genl_allocate_reserve_groups(n_groups, &first_id);
219 if (err)
220 return err;
221 }
222
223 family->mcgrp_offset = first_id;
224
225 /* if still initializing, can't and don't need to to realloc bitmaps */
226 if (!init_net.genl_sock)
227 return 0;
228
229 if (family->netnsok) {
230 struct net *net;
231
232 netlink_table_grab();
233 rcu_read_lock();
234 for_each_net_rcu(net) {
235 err = __netlink_change_ngroups(net->genl_sock,
236 mc_groups_longs * BITS_PER_LONG);
237 if (err) {
238 /*
239 * No need to roll back, can only fail if
240 * memory allocation fails and then the
241 * number of _possible_ groups has been
242 * increased on some sockets which is ok.
243 */
244 break;
245 }
246 }
247 rcu_read_unlock();
248 netlink_table_ungrab();
249 } else {
250 err = netlink_change_ngroups(init_net.genl_sock,
251 mc_groups_longs * BITS_PER_LONG);
252 }
253
254 if (groups_allocated && err) {
255 for (i = 0; i < family->n_mcgrps; i++)
256 clear_bit(family->mcgrp_offset + i, mc_groups);
257 }
258
259 return err;
260}
261
262static void genl_unregister_mc_groups(const struct genl_family *family)
263{
264 struct net *net;
265 int i;
266
267 netlink_table_grab();
268 rcu_read_lock();
269 for_each_net_rcu(net) {
270 for (i = 0; i < family->n_mcgrps; i++)
271 __netlink_clear_multicast_users(
272 net->genl_sock, family->mcgrp_offset + i);
273 }
274 rcu_read_unlock();
275 netlink_table_ungrab();
276
277 for (i = 0; i < family->n_mcgrps; i++) {
278 int grp_id = family->mcgrp_offset + i;
279
280 if (grp_id != 1)
281 clear_bit(grp_id, mc_groups);
282 genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, family,
283 &family->mcgrps[i], grp_id);
284 }
285}
286
287static int genl_validate_ops(const struct genl_family *family)
288{
289 const struct genl_ops *ops = family->ops;
290 unsigned int n_ops = family->n_ops;
291 int i, j;
292
293 if (WARN_ON(n_ops && !ops))
294 return -EINVAL;
295
296 if (!n_ops)
297 return 0;
298
299 for (i = 0; i < n_ops; i++) {
300 if (ops[i].dumpit == NULL && ops[i].doit == NULL)
301 return -EINVAL;
302 for (j = i + 1; j < n_ops; j++)
303 if (ops[i].cmd == ops[j].cmd)
304 return -EINVAL;
305 }
306
307 return 0;
308}
309
310/**
311 * genl_register_family - register a generic netlink family
312 * @family: generic netlink family
313 *
314 * Registers the specified family after validating it first. Only one
315 * family may be registered with the same family name or identifier.
316 *
317 * The family's ops, multicast groups and module pointer must already
318 * be assigned.
319 *
320 * Return 0 on success or a negative error code.
321 */
322int genl_register_family(struct genl_family *family)
323{
324 int err, i;
325 int start = GENL_START_ALLOC, end = GENL_MAX_ID;
326
327 err = genl_validate_ops(family);
328 if (err)
329 return err;
330
331 genl_lock_all();
332
333 if (genl_family_find_byname(family->name)) {
334 err = -EEXIST;
335 goto errout_locked;
336 }
337
338 /*
339 * Sadly, a few cases need to be special-cased
340 * due to them having previously abused the API
341 * and having used their family ID also as their
342 * multicast group ID, so we use reserved IDs
343 * for both to be sure we can do that mapping.
344 */
345 if (family == &genl_ctrl) {
346 /* and this needs to be special for initial family lookups */
347 start = end = GENL_ID_CTRL;
348 } else if (strcmp(family->name, "pmcraid") == 0) {
349 start = end = GENL_ID_PMCRAID;
350 } else if (strcmp(family->name, "VFS_DQUOT") == 0) {
351 start = end = GENL_ID_VFS_DQUOT;
352 }
353
354 if (family->maxattr && !family->parallel_ops) {
355 family->attrbuf = kmalloc_array(family->maxattr + 1,
356 sizeof(struct nlattr *),
357 GFP_KERNEL);
358 if (family->attrbuf == NULL) {
359 err = -ENOMEM;
360 goto errout_locked;
361 }
362 } else
363 family->attrbuf = NULL;
364
365 family->id = idr_alloc_cyclic(&genl_fam_idr, family,
366 start, end + 1, GFP_KERNEL);
367 if (family->id < 0) {
368 err = family->id;
369 goto errout_free;
370 }
371
372 err = genl_validate_assign_mc_groups(family);
373 if (err)
374 goto errout_remove;
375
376 genl_unlock_all();
377
378 /* send all events */
379 genl_ctrl_event(CTRL_CMD_NEWFAMILY, family, NULL, 0);
380 for (i = 0; i < family->n_mcgrps; i++)
381 genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, family,
382 &family->mcgrps[i], family->mcgrp_offset + i);
383
384 return 0;
385
386errout_remove:
387 idr_remove(&genl_fam_idr, family->id);
388errout_free:
389 kfree(family->attrbuf);
390errout_locked:
391 genl_unlock_all();
392 return err;
393}
394EXPORT_SYMBOL(genl_register_family);
395
396/**
397 * genl_unregister_family - unregister generic netlink family
398 * @family: generic netlink family
399 *
400 * Unregisters the specified family.
401 *
402 * Returns 0 on success or a negative error code.
403 */
404int genl_unregister_family(const struct genl_family *family)
405{
406 genl_lock_all();
407
408 if (!genl_family_find_byid(family->id)) {
409 genl_unlock_all();
410 return -ENOENT;
411 }
412
413 genl_unregister_mc_groups(family);
414
415 idr_remove(&genl_fam_idr, family->id);
416
417 up_write(&cb_lock);
418 wait_event(genl_sk_destructing_waitq,
419 atomic_read(&genl_sk_destructing_cnt) == 0);
420 genl_unlock();
421
422 kfree(family->attrbuf);
423
424 genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 0);
425
426 return 0;
427}
428EXPORT_SYMBOL(genl_unregister_family);
429
430/**
431 * genlmsg_put - Add generic netlink header to netlink message
432 * @skb: socket buffer holding the message
433 * @portid: netlink portid the message is addressed to
434 * @seq: sequence number (usually the one of the sender)
435 * @family: generic netlink family
436 * @flags: netlink message flags
437 * @cmd: generic netlink command
438 *
439 * Returns pointer to user specific header
440 */
441void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
442 const struct genl_family *family, int flags, u8 cmd)
443{
444 struct nlmsghdr *nlh;
445 struct genlmsghdr *hdr;
446
447 nlh = nlmsg_put(skb, portid, seq, family->id, GENL_HDRLEN +
448 family->hdrsize, flags);
449 if (nlh == NULL)
450 return NULL;
451
452 hdr = nlmsg_data(nlh);
453 hdr->cmd = cmd;
454 hdr->version = family->version;
455 hdr->reserved = 0;
456
457 return (char *) hdr + GENL_HDRLEN;
458}
459EXPORT_SYMBOL(genlmsg_put);
460
461static int genl_lock_start(struct netlink_callback *cb)
462{
463 /* our ops are always const - netlink API doesn't propagate that */
464 const struct genl_ops *ops = cb->data;
465 int rc = 0;
466
467 if (ops->start) {
468 genl_lock();
469 rc = ops->start(cb);
470 genl_unlock();
471 }
472 return rc;
473}
474
475static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
476{
477 /* our ops are always const - netlink API doesn't propagate that */
478 const struct genl_ops *ops = cb->data;
479 int rc;
480
481 genl_lock();
482 rc = ops->dumpit(skb, cb);
483 genl_unlock();
484 return rc;
485}
486
487static int genl_lock_done(struct netlink_callback *cb)
488{
489 /* our ops are always const - netlink API doesn't propagate that */
490 const struct genl_ops *ops = cb->data;
491 int rc = 0;
492
493 if (ops->done) {
494 genl_lock();
495 rc = ops->done(cb);
496 genl_unlock();
497 }
498 return rc;
499}
500
501static int genl_family_rcv_msg(const struct genl_family *family,
502 struct sk_buff *skb,
503 struct nlmsghdr *nlh,
504 struct netlink_ext_ack *extack)
505{
506 const struct genl_ops *ops;
507 struct net *net = sock_net(skb->sk);
508 struct genl_info info;
509 struct genlmsghdr *hdr = nlmsg_data(nlh);
510 struct nlattr **attrbuf;
511 int hdrlen, err;
512
513 /* this family doesn't exist in this netns */
514 if (!family->netnsok && !net_eq(net, &init_net))
515 return -ENOENT;
516
517 hdrlen = GENL_HDRLEN + family->hdrsize;
518 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
519 return -EINVAL;
520
521 ops = genl_get_cmd(hdr->cmd, family);
522 if (ops == NULL)
523 return -EOPNOTSUPP;
524
525 if ((ops->flags & GENL_ADMIN_PERM) &&
526 !netlink_capable(skb, CAP_NET_ADMIN))
527 return -EPERM;
528
529 if ((ops->flags & GENL_UNS_ADMIN_PERM) &&
530 !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
531 return -EPERM;
532
533 if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP) {
534 int rc;
535
536 if (ops->dumpit == NULL)
537 return -EOPNOTSUPP;
538
539 if (!(ops->validate & GENL_DONT_VALIDATE_DUMP)) {
540 int hdrlen = GENL_HDRLEN + family->hdrsize;
541
542 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
543 return -EINVAL;
544
545 if (family->maxattr) {
546 unsigned int validate = NL_VALIDATE_STRICT;
547
548 if (ops->validate &
549 GENL_DONT_VALIDATE_DUMP_STRICT)
550 validate = NL_VALIDATE_LIBERAL;
551 rc = __nla_validate(nlmsg_attrdata(nlh, hdrlen),
552 nlmsg_attrlen(nlh, hdrlen),
553 family->maxattr,
554 family->policy,
555 validate, extack);
556 if (rc)
557 return rc;
558 }
559 }
560
561 if (!family->parallel_ops) {
562 struct netlink_dump_control c = {
563 .module = family->module,
564 /* we have const, but the netlink API doesn't */
565 .data = (void *)ops,
566 .start = genl_lock_start,
567 .dump = genl_lock_dumpit,
568 .done = genl_lock_done,
569 };
570
571 genl_unlock();
572 rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
573 genl_lock();
574
575 } else {
576 struct netlink_dump_control c = {
577 .module = family->module,
578 .start = ops->start,
579 .dump = ops->dumpit,
580 .done = ops->done,
581 };
582
583 rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
584 }
585
586 return rc;
587 }
588
589 if (ops->doit == NULL)
590 return -EOPNOTSUPP;
591
592 if (family->maxattr && family->parallel_ops) {
593 attrbuf = kmalloc_array(family->maxattr + 1,
594 sizeof(struct nlattr *),
595 GFP_KERNEL);
596 if (attrbuf == NULL)
597 return -ENOMEM;
598 } else
599 attrbuf = family->attrbuf;
600
601 if (attrbuf) {
602 enum netlink_validation validate = NL_VALIDATE_STRICT;
603
604 if (ops->validate & GENL_DONT_VALIDATE_STRICT)
605 validate = NL_VALIDATE_LIBERAL;
606
607 err = __nlmsg_parse(nlh, hdrlen, attrbuf, family->maxattr,
608 family->policy, validate, extack);
609 if (err < 0)
610 goto out;
611 }
612
613 info.snd_seq = nlh->nlmsg_seq;
614 info.snd_portid = NETLINK_CB(skb).portid;
615 info.nlhdr = nlh;
616 info.genlhdr = nlmsg_data(nlh);
617 info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
618 info.attrs = attrbuf;
619 info.extack = extack;
620 genl_info_net_set(&info, net);
621 memset(&info.user_ptr, 0, sizeof(info.user_ptr));
622
623 if (family->pre_doit) {
624 err = family->pre_doit(ops, skb, &info);
625 if (err)
626 goto out;
627 }
628
629 err = ops->doit(skb, &info);
630
631 if (family->post_doit)
632 family->post_doit(ops, skb, &info);
633
634out:
635 if (family->parallel_ops)
636 kfree(attrbuf);
637
638 return err;
639}
640
641static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
642 struct netlink_ext_ack *extack)
643{
644 const struct genl_family *family;
645 int err;
646
647 family = genl_family_find_byid(nlh->nlmsg_type);
648 if (family == NULL)
649 return -ENOENT;
650
651 if (!family->parallel_ops)
652 genl_lock();
653
654 err = genl_family_rcv_msg(family, skb, nlh, extack);
655
656 if (!family->parallel_ops)
657 genl_unlock();
658
659 return err;
660}
661
662static void genl_rcv(struct sk_buff *skb)
663{
664 down_read(&cb_lock);
665 netlink_rcv_skb(skb, &genl_rcv_msg);
666 up_read(&cb_lock);
667}
668
669/**************************************************************************
670 * Controller
671 **************************************************************************/
672
673static struct genl_family genl_ctrl;
674
675static int ctrl_fill_info(const struct genl_family *family, u32 portid, u32 seq,
676 u32 flags, struct sk_buff *skb, u8 cmd)
677{
678 void *hdr;
679
680 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
681 if (hdr == NULL)
682 return -1;
683
684 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
685 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) ||
686 nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) ||
687 nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) ||
688 nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr))
689 goto nla_put_failure;
690
691 if (family->n_ops) {
692 struct nlattr *nla_ops;
693 int i;
694
695 nla_ops = nla_nest_start_noflag(skb, CTRL_ATTR_OPS);
696 if (nla_ops == NULL)
697 goto nla_put_failure;
698
699 for (i = 0; i < family->n_ops; i++) {
700 struct nlattr *nest;
701 const struct genl_ops *ops = &family->ops[i];
702 u32 op_flags = ops->flags;
703
704 if (ops->dumpit)
705 op_flags |= GENL_CMD_CAP_DUMP;
706 if (ops->doit)
707 op_flags |= GENL_CMD_CAP_DO;
708 if (family->policy)
709 op_flags |= GENL_CMD_CAP_HASPOL;
710
711 nest = nla_nest_start_noflag(skb, i + 1);
712 if (nest == NULL)
713 goto nla_put_failure;
714
715 if (nla_put_u32(skb, CTRL_ATTR_OP_ID, ops->cmd) ||
716 nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, op_flags))
717 goto nla_put_failure;
718
719 nla_nest_end(skb, nest);
720 }
721
722 nla_nest_end(skb, nla_ops);
723 }
724
725 if (family->n_mcgrps) {
726 struct nlattr *nla_grps;
727 int i;
728
729 nla_grps = nla_nest_start_noflag(skb, CTRL_ATTR_MCAST_GROUPS);
730 if (nla_grps == NULL)
731 goto nla_put_failure;
732
733 for (i = 0; i < family->n_mcgrps; i++) {
734 struct nlattr *nest;
735 const struct genl_multicast_group *grp;
736
737 grp = &family->mcgrps[i];
738
739 nest = nla_nest_start_noflag(skb, i + 1);
740 if (nest == NULL)
741 goto nla_put_failure;
742
743 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID,
744 family->mcgrp_offset + i) ||
745 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
746 grp->name))
747 goto nla_put_failure;
748
749 nla_nest_end(skb, nest);
750 }
751 nla_nest_end(skb, nla_grps);
752 }
753
754 genlmsg_end(skb, hdr);
755 return 0;
756
757nla_put_failure:
758 genlmsg_cancel(skb, hdr);
759 return -EMSGSIZE;
760}
761
762static int ctrl_fill_mcgrp_info(const struct genl_family *family,
763 const struct genl_multicast_group *grp,
764 int grp_id, u32 portid, u32 seq, u32 flags,
765 struct sk_buff *skb, u8 cmd)
766{
767 void *hdr;
768 struct nlattr *nla_grps;
769 struct nlattr *nest;
770
771 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
772 if (hdr == NULL)
773 return -1;
774
775 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
776 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id))
777 goto nla_put_failure;
778
779 nla_grps = nla_nest_start_noflag(skb, CTRL_ATTR_MCAST_GROUPS);
780 if (nla_grps == NULL)
781 goto nla_put_failure;
782
783 nest = nla_nest_start_noflag(skb, 1);
784 if (nest == NULL)
785 goto nla_put_failure;
786
787 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp_id) ||
788 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
789 grp->name))
790 goto nla_put_failure;
791
792 nla_nest_end(skb, nest);
793 nla_nest_end(skb, nla_grps);
794
795 genlmsg_end(skb, hdr);
796 return 0;
797
798nla_put_failure:
799 genlmsg_cancel(skb, hdr);
800 return -EMSGSIZE;
801}
802
803static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
804{
805 int n = 0;
806 struct genl_family *rt;
807 struct net *net = sock_net(skb->sk);
808 int fams_to_skip = cb->args[0];
809 unsigned int id;
810
811 idr_for_each_entry(&genl_fam_idr, rt, id) {
812 if (!rt->netnsok && !net_eq(net, &init_net))
813 continue;
814
815 if (n++ < fams_to_skip)
816 continue;
817
818 if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid,
819 cb->nlh->nlmsg_seq, NLM_F_MULTI,
820 skb, CTRL_CMD_NEWFAMILY) < 0) {
821 n--;
822 break;
823 }
824 }
825
826 cb->args[0] = n;
827 return skb->len;
828}
829
830static struct sk_buff *ctrl_build_family_msg(const struct genl_family *family,
831 u32 portid, int seq, u8 cmd)
832{
833 struct sk_buff *skb;
834 int err;
835
836 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
837 if (skb == NULL)
838 return ERR_PTR(-ENOBUFS);
839
840 err = ctrl_fill_info(family, portid, seq, 0, skb, cmd);
841 if (err < 0) {
842 nlmsg_free(skb);
843 return ERR_PTR(err);
844 }
845
846 return skb;
847}
848
849static struct sk_buff *
850ctrl_build_mcgrp_msg(const struct genl_family *family,
851 const struct genl_multicast_group *grp,
852 int grp_id, u32 portid, int seq, u8 cmd)
853{
854 struct sk_buff *skb;
855 int err;
856
857 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
858 if (skb == NULL)
859 return ERR_PTR(-ENOBUFS);
860
861 err = ctrl_fill_mcgrp_info(family, grp, grp_id, portid,
862 seq, 0, skb, cmd);
863 if (err < 0) {
864 nlmsg_free(skb);
865 return ERR_PTR(err);
866 }
867
868 return skb;
869}
870
871static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
872 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 },
873 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
874 .len = GENL_NAMSIZ - 1 },
875};
876
877static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
878{
879 struct sk_buff *msg;
880 const struct genl_family *res = NULL;
881 int err = -EINVAL;
882
883 if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
884 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
885 res = genl_family_find_byid(id);
886 err = -ENOENT;
887 }
888
889 if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
890 char *name;
891
892 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
893 res = genl_family_find_byname(name);
894#ifdef CONFIG_MODULES
895 if (res == NULL) {
896 genl_unlock();
897 up_read(&cb_lock);
898 request_module("net-pf-%d-proto-%d-family-%s",
899 PF_NETLINK, NETLINK_GENERIC, name);
900 down_read(&cb_lock);
901 genl_lock();
902 res = genl_family_find_byname(name);
903 }
904#endif
905 err = -ENOENT;
906 }
907
908 if (res == NULL)
909 return err;
910
911 if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) {
912 /* family doesn't exist here */
913 return -ENOENT;
914 }
915
916 msg = ctrl_build_family_msg(res, info->snd_portid, info->snd_seq,
917 CTRL_CMD_NEWFAMILY);
918 if (IS_ERR(msg))
919 return PTR_ERR(msg);
920
921 return genlmsg_reply(msg, info);
922}
923
924static int genl_ctrl_event(int event, const struct genl_family *family,
925 const struct genl_multicast_group *grp,
926 int grp_id)
927{
928 struct sk_buff *msg;
929
930 /* genl is still initialising */
931 if (!init_net.genl_sock)
932 return 0;
933
934 switch (event) {
935 case CTRL_CMD_NEWFAMILY:
936 case CTRL_CMD_DELFAMILY:
937 WARN_ON(grp);
938 msg = ctrl_build_family_msg(family, 0, 0, event);
939 break;
940 case CTRL_CMD_NEWMCAST_GRP:
941 case CTRL_CMD_DELMCAST_GRP:
942 BUG_ON(!grp);
943 msg = ctrl_build_mcgrp_msg(family, grp, grp_id, 0, 0, event);
944 break;
945 default:
946 return -EINVAL;
947 }
948
949 if (IS_ERR(msg))
950 return PTR_ERR(msg);
951
952 if (!family->netnsok) {
953 genlmsg_multicast_netns(&genl_ctrl, &init_net, msg, 0,
954 0, GFP_KERNEL);
955 } else {
956 rcu_read_lock();
957 genlmsg_multicast_allns(&genl_ctrl, msg, 0,
958 0, GFP_ATOMIC);
959 rcu_read_unlock();
960 }
961
962 return 0;
963}
964
965static const struct genl_ops genl_ctrl_ops[] = {
966 {
967 .cmd = CTRL_CMD_GETFAMILY,
968 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
969 .doit = ctrl_getfamily,
970 .dumpit = ctrl_dumpfamily,
971 },
972};
973
974static const struct genl_multicast_group genl_ctrl_groups[] = {
975 { .name = "notify", },
976};
977
978static struct genl_family genl_ctrl __ro_after_init = {
979 .module = THIS_MODULE,
980 .ops = genl_ctrl_ops,
981 .n_ops = ARRAY_SIZE(genl_ctrl_ops),
982 .mcgrps = genl_ctrl_groups,
983 .n_mcgrps = ARRAY_SIZE(genl_ctrl_groups),
984 .id = GENL_ID_CTRL,
985 .name = "nlctrl",
986 .version = 0x2,
987 .maxattr = CTRL_ATTR_MAX,
988 .policy = ctrl_policy,
989 .netnsok = true,
990};
991
992static int genl_bind(struct net *net, int group)
993{
994 struct genl_family *f;
995 int err = -ENOENT;
996 unsigned int id;
997
998 down_read(&cb_lock);
999
1000 idr_for_each_entry(&genl_fam_idr, f, id) {
1001 if (group >= f->mcgrp_offset &&
1002 group < f->mcgrp_offset + f->n_mcgrps) {
1003 int fam_grp = group - f->mcgrp_offset;
1004
1005 if (!f->netnsok && net != &init_net)
1006 err = -ENOENT;
1007 else if (f->mcast_bind)
1008 err = f->mcast_bind(net, fam_grp);
1009 else
1010 err = 0;
1011 break;
1012 }
1013 }
1014 up_read(&cb_lock);
1015
1016 return err;
1017}
1018
1019static void genl_unbind(struct net *net, int group)
1020{
1021 struct genl_family *f;
1022 unsigned int id;
1023
1024 down_read(&cb_lock);
1025
1026 idr_for_each_entry(&genl_fam_idr, f, id) {
1027 if (group >= f->mcgrp_offset &&
1028 group < f->mcgrp_offset + f->n_mcgrps) {
1029 int fam_grp = group - f->mcgrp_offset;
1030
1031 if (f->mcast_unbind)
1032 f->mcast_unbind(net, fam_grp);
1033 break;
1034 }
1035 }
1036 up_read(&cb_lock);
1037}
1038
1039static int __net_init genl_pernet_init(struct net *net)
1040{
1041 struct netlink_kernel_cfg cfg = {
1042 .input = genl_rcv,
1043 .flags = NL_CFG_F_NONROOT_RECV,
1044 .bind = genl_bind,
1045 .unbind = genl_unbind,
1046 };
1047
1048 /* we'll bump the group number right afterwards */
1049 net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg);
1050
1051 if (!net->genl_sock && net_eq(net, &init_net))
1052 panic("GENL: Cannot initialize generic netlink\n");
1053
1054 if (!net->genl_sock)
1055 return -ENOMEM;
1056
1057 return 0;
1058}
1059
1060static void __net_exit genl_pernet_exit(struct net *net)
1061{
1062 netlink_kernel_release(net->genl_sock);
1063 net->genl_sock = NULL;
1064}
1065
1066static struct pernet_operations genl_pernet_ops = {
1067 .init = genl_pernet_init,
1068 .exit = genl_pernet_exit,
1069};
1070
1071static int __init genl_init(void)
1072{
1073 int err;
1074
1075 err = genl_register_family(&genl_ctrl);
1076 if (err < 0)
1077 goto problem;
1078
1079 err = register_pernet_subsys(&genl_pernet_ops);
1080 if (err)
1081 goto problem;
1082
1083 return 0;
1084
1085problem:
1086 panic("GENL: Cannot register controller: %d\n", err);
1087}
1088
1089subsys_initcall(genl_init);
1090
1091/**
1092 * genl_family_attrbuf - return family's attrbuf
1093 * @family: the family
1094 *
1095 * Return the family's attrbuf, while validating that it's
1096 * actually valid to access it.
1097 *
1098 * You cannot use this function with a family that has parallel_ops
1099 * and you can only use it within (pre/post) doit/dumpit callbacks.
1100 */
1101struct nlattr **genl_family_attrbuf(const struct genl_family *family)
1102{
1103 if (!WARN_ON(family->parallel_ops))
1104 lockdep_assert_held(&genl_mutex);
1105
1106 return family->attrbuf;
1107}
1108EXPORT_SYMBOL(genl_family_attrbuf);
1109
1110static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
1111 gfp_t flags)
1112{
1113 struct sk_buff *tmp;
1114 struct net *net, *prev = NULL;
1115 bool delivered = false;
1116 int err;
1117
1118 for_each_net_rcu(net) {
1119 if (prev) {
1120 tmp = skb_clone(skb, flags);
1121 if (!tmp) {
1122 err = -ENOMEM;
1123 goto error;
1124 }
1125 err = nlmsg_multicast(prev->genl_sock, tmp,
1126 portid, group, flags);
1127 if (!err)
1128 delivered = true;
1129 else if (err != -ESRCH)
1130 goto error;
1131 }
1132
1133 prev = net;
1134 }
1135
1136 err = nlmsg_multicast(prev->genl_sock, skb, portid, group, flags);
1137 if (!err)
1138 delivered = true;
1139 else if (err != -ESRCH)
1140 return err;
1141 return delivered ? 0 : -ESRCH;
1142 error:
1143 kfree_skb(skb);
1144 return err;
1145}
1146
1147int genlmsg_multicast_allns(const struct genl_family *family,
1148 struct sk_buff *skb, u32 portid,
1149 unsigned int group, gfp_t flags)
1150{
1151 if (WARN_ON_ONCE(group >= family->n_mcgrps))
1152 return -EINVAL;
1153 group = family->mcgrp_offset + group;
1154 return genlmsg_mcast(skb, portid, group, flags);
1155}
1156EXPORT_SYMBOL(genlmsg_multicast_allns);
1157
1158void genl_notify(const struct genl_family *family, struct sk_buff *skb,
1159 struct genl_info *info, u32 group, gfp_t flags)
1160{
1161 struct net *net = genl_info_net(info);
1162 struct sock *sk = net->genl_sock;
1163 int report = 0;
1164
1165 if (info->nlhdr)
1166 report = nlmsg_report(info->nlhdr);
1167
1168 if (WARN_ON_ONCE(group >= family->n_mcgrps))
1169 return;
1170 group = family->mcgrp_offset + group;
1171 nlmsg_notify(sk, skb, info->snd_portid, group, report, flags);
1172}
1173EXPORT_SYMBOL(genl_notify);
1/*
2 * NETLINK Generic Netlink Family
3 *
4 * Authors: Jamal Hadi Salim
5 * Thomas Graf <tgraf@suug.ch>
6 * Johannes Berg <johannes@sipsolutions.net>
7 */
8
9#include <linux/module.h>
10#include <linux/kernel.h>
11#include <linux/slab.h>
12#include <linux/errno.h>
13#include <linux/types.h>
14#include <linux/socket.h>
15#include <linux/string.h>
16#include <linux/skbuff.h>
17#include <linux/mutex.h>
18#include <linux/bitmap.h>
19#include <net/sock.h>
20#include <net/genetlink.h>
21
22static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */
23
24void genl_lock(void)
25{
26 mutex_lock(&genl_mutex);
27}
28EXPORT_SYMBOL(genl_lock);
29
30void genl_unlock(void)
31{
32 mutex_unlock(&genl_mutex);
33}
34EXPORT_SYMBOL(genl_unlock);
35
36#define GENL_FAM_TAB_SIZE 16
37#define GENL_FAM_TAB_MASK (GENL_FAM_TAB_SIZE - 1)
38
39static struct list_head family_ht[GENL_FAM_TAB_SIZE];
40/*
41 * Bitmap of multicast groups that are currently in use.
42 *
43 * To avoid an allocation at boot of just one unsigned long,
44 * declare it global instead.
45 * Bit 0 is marked as already used since group 0 is invalid.
46 */
47static unsigned long mc_group_start = 0x1;
48static unsigned long *mc_groups = &mc_group_start;
49static unsigned long mc_groups_longs = 1;
50
51static int genl_ctrl_event(int event, void *data);
52
53static inline unsigned int genl_family_hash(unsigned int id)
54{
55 return id & GENL_FAM_TAB_MASK;
56}
57
58static inline struct list_head *genl_family_chain(unsigned int id)
59{
60 return &family_ht[genl_family_hash(id)];
61}
62
63static struct genl_family *genl_family_find_byid(unsigned int id)
64{
65 struct genl_family *f;
66
67 list_for_each_entry(f, genl_family_chain(id), family_list)
68 if (f->id == id)
69 return f;
70
71 return NULL;
72}
73
74static struct genl_family *genl_family_find_byname(char *name)
75{
76 struct genl_family *f;
77 int i;
78
79 for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
80 list_for_each_entry(f, genl_family_chain(i), family_list)
81 if (strcmp(f->name, name) == 0)
82 return f;
83
84 return NULL;
85}
86
87static struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family)
88{
89 struct genl_ops *ops;
90
91 list_for_each_entry(ops, &family->ops_list, ops_list)
92 if (ops->cmd == cmd)
93 return ops;
94
95 return NULL;
96}
97
98/* Of course we are going to have problems once we hit
99 * 2^16 alive types, but that can only happen by year 2K
100*/
101static inline u16 genl_generate_id(void)
102{
103 static u16 id_gen_idx = GENL_MIN_ID;
104 int i;
105
106 for (i = 0; i <= GENL_MAX_ID - GENL_MIN_ID; i++) {
107 if (!genl_family_find_byid(id_gen_idx))
108 return id_gen_idx;
109 if (++id_gen_idx > GENL_MAX_ID)
110 id_gen_idx = GENL_MIN_ID;
111 }
112
113 return 0;
114}
115
116static struct genl_multicast_group notify_grp;
117
118/**
119 * genl_register_mc_group - register a multicast group
120 *
121 * Registers the specified multicast group and notifies userspace
122 * about the new group.
123 *
124 * Returns 0 on success or a negative error code.
125 *
126 * @family: The generic netlink family the group shall be registered for.
127 * @grp: The group to register, must have a name.
128 */
129int genl_register_mc_group(struct genl_family *family,
130 struct genl_multicast_group *grp)
131{
132 int id;
133 unsigned long *new_groups;
134 int err = 0;
135
136 BUG_ON(grp->name[0] == '\0');
137
138 genl_lock();
139
140 /* special-case our own group */
141 if (grp == ¬ify_grp)
142 id = GENL_ID_CTRL;
143 else
144 id = find_first_zero_bit(mc_groups,
145 mc_groups_longs * BITS_PER_LONG);
146
147
148 if (id >= mc_groups_longs * BITS_PER_LONG) {
149 size_t nlen = (mc_groups_longs + 1) * sizeof(unsigned long);
150
151 if (mc_groups == &mc_group_start) {
152 new_groups = kzalloc(nlen, GFP_KERNEL);
153 if (!new_groups) {
154 err = -ENOMEM;
155 goto out;
156 }
157 mc_groups = new_groups;
158 *mc_groups = mc_group_start;
159 } else {
160 new_groups = krealloc(mc_groups, nlen, GFP_KERNEL);
161 if (!new_groups) {
162 err = -ENOMEM;
163 goto out;
164 }
165 mc_groups = new_groups;
166 mc_groups[mc_groups_longs] = 0;
167 }
168 mc_groups_longs++;
169 }
170
171 if (family->netnsok) {
172 struct net *net;
173
174 netlink_table_grab();
175 rcu_read_lock();
176 for_each_net_rcu(net) {
177 err = __netlink_change_ngroups(net->genl_sock,
178 mc_groups_longs * BITS_PER_LONG);
179 if (err) {
180 /*
181 * No need to roll back, can only fail if
182 * memory allocation fails and then the
183 * number of _possible_ groups has been
184 * increased on some sockets which is ok.
185 */
186 rcu_read_unlock();
187 netlink_table_ungrab();
188 goto out;
189 }
190 }
191 rcu_read_unlock();
192 netlink_table_ungrab();
193 } else {
194 err = netlink_change_ngroups(init_net.genl_sock,
195 mc_groups_longs * BITS_PER_LONG);
196 if (err)
197 goto out;
198 }
199
200 grp->id = id;
201 set_bit(id, mc_groups);
202 list_add_tail(&grp->list, &family->mcast_groups);
203 grp->family = family;
204
205 genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, grp);
206 out:
207 genl_unlock();
208 return err;
209}
210EXPORT_SYMBOL(genl_register_mc_group);
211
212static void __genl_unregister_mc_group(struct genl_family *family,
213 struct genl_multicast_group *grp)
214{
215 struct net *net;
216 BUG_ON(grp->family != family);
217
218 netlink_table_grab();
219 rcu_read_lock();
220 for_each_net_rcu(net)
221 __netlink_clear_multicast_users(net->genl_sock, grp->id);
222 rcu_read_unlock();
223 netlink_table_ungrab();
224
225 clear_bit(grp->id, mc_groups);
226 list_del(&grp->list);
227 genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, grp);
228 grp->id = 0;
229 grp->family = NULL;
230}
231
232/**
233 * genl_unregister_mc_group - unregister a multicast group
234 *
235 * Unregisters the specified multicast group and notifies userspace
236 * about it. All current listeners on the group are removed.
237 *
238 * Note: It is not necessary to unregister all multicast groups before
239 * unregistering the family, unregistering the family will cause
240 * all assigned multicast groups to be unregistered automatically.
241 *
242 * @family: Generic netlink family the group belongs to.
243 * @grp: The group to unregister, must have been registered successfully
244 * previously.
245 */
246void genl_unregister_mc_group(struct genl_family *family,
247 struct genl_multicast_group *grp)
248{
249 genl_lock();
250 __genl_unregister_mc_group(family, grp);
251 genl_unlock();
252}
253EXPORT_SYMBOL(genl_unregister_mc_group);
254
255static void genl_unregister_mc_groups(struct genl_family *family)
256{
257 struct genl_multicast_group *grp, *tmp;
258
259 list_for_each_entry_safe(grp, tmp, &family->mcast_groups, list)
260 __genl_unregister_mc_group(family, grp);
261}
262
263/**
264 * genl_register_ops - register generic netlink operations
265 * @family: generic netlink family
266 * @ops: operations to be registered
267 *
268 * Registers the specified operations and assigns them to the specified
269 * family. Either a doit or dumpit callback must be specified or the
270 * operation will fail. Only one operation structure per command
271 * identifier may be registered.
272 *
273 * See include/net/genetlink.h for more documenation on the operations
274 * structure.
275 *
276 * Returns 0 on success or a negative error code.
277 */
278int genl_register_ops(struct genl_family *family, struct genl_ops *ops)
279{
280 int err = -EINVAL;
281
282 if (ops->dumpit == NULL && ops->doit == NULL)
283 goto errout;
284
285 if (genl_get_cmd(ops->cmd, family)) {
286 err = -EEXIST;
287 goto errout;
288 }
289
290 if (ops->dumpit)
291 ops->flags |= GENL_CMD_CAP_DUMP;
292 if (ops->doit)
293 ops->flags |= GENL_CMD_CAP_DO;
294 if (ops->policy)
295 ops->flags |= GENL_CMD_CAP_HASPOL;
296
297 genl_lock();
298 list_add_tail(&ops->ops_list, &family->ops_list);
299 genl_unlock();
300
301 genl_ctrl_event(CTRL_CMD_NEWOPS, ops);
302 err = 0;
303errout:
304 return err;
305}
306EXPORT_SYMBOL(genl_register_ops);
307
308/**
309 * genl_unregister_ops - unregister generic netlink operations
310 * @family: generic netlink family
311 * @ops: operations to be unregistered
312 *
313 * Unregisters the specified operations and unassigns them from the
314 * specified family. The operation blocks until the current message
315 * processing has finished and doesn't start again until the
316 * unregister process has finished.
317 *
318 * Note: It is not necessary to unregister all operations before
319 * unregistering the family, unregistering the family will cause
320 * all assigned operations to be unregistered automatically.
321 *
322 * Returns 0 on success or a negative error code.
323 */
324int genl_unregister_ops(struct genl_family *family, struct genl_ops *ops)
325{
326 struct genl_ops *rc;
327
328 genl_lock();
329 list_for_each_entry(rc, &family->ops_list, ops_list) {
330 if (rc == ops) {
331 list_del(&ops->ops_list);
332 genl_unlock();
333 genl_ctrl_event(CTRL_CMD_DELOPS, ops);
334 return 0;
335 }
336 }
337 genl_unlock();
338
339 return -ENOENT;
340}
341EXPORT_SYMBOL(genl_unregister_ops);
342
343/**
344 * genl_register_family - register a generic netlink family
345 * @family: generic netlink family
346 *
347 * Registers the specified family after validating it first. Only one
348 * family may be registered with the same family name or identifier.
349 * The family id may equal GENL_ID_GENERATE causing an unique id to
350 * be automatically generated and assigned.
351 *
352 * Return 0 on success or a negative error code.
353 */
354int genl_register_family(struct genl_family *family)
355{
356 int err = -EINVAL;
357
358 if (family->id && family->id < GENL_MIN_ID)
359 goto errout;
360
361 if (family->id > GENL_MAX_ID)
362 goto errout;
363
364 INIT_LIST_HEAD(&family->ops_list);
365 INIT_LIST_HEAD(&family->mcast_groups);
366
367 genl_lock();
368
369 if (genl_family_find_byname(family->name)) {
370 err = -EEXIST;
371 goto errout_locked;
372 }
373
374 if (family->id == GENL_ID_GENERATE) {
375 u16 newid = genl_generate_id();
376
377 if (!newid) {
378 err = -ENOMEM;
379 goto errout_locked;
380 }
381
382 family->id = newid;
383 } else if (genl_family_find_byid(family->id)) {
384 err = -EEXIST;
385 goto errout_locked;
386 }
387
388 if (family->maxattr) {
389 family->attrbuf = kmalloc((family->maxattr+1) *
390 sizeof(struct nlattr *), GFP_KERNEL);
391 if (family->attrbuf == NULL) {
392 err = -ENOMEM;
393 goto errout_locked;
394 }
395 } else
396 family->attrbuf = NULL;
397
398 list_add_tail(&family->family_list, genl_family_chain(family->id));
399 genl_unlock();
400
401 genl_ctrl_event(CTRL_CMD_NEWFAMILY, family);
402
403 return 0;
404
405errout_locked:
406 genl_unlock();
407errout:
408 return err;
409}
410EXPORT_SYMBOL(genl_register_family);
411
412/**
413 * genl_register_family_with_ops - register a generic netlink family
414 * @family: generic netlink family
415 * @ops: operations to be registered
416 * @n_ops: number of elements to register
417 *
418 * Registers the specified family and operations from the specified table.
419 * Only one family may be registered with the same family name or identifier.
420 *
421 * The family id may equal GENL_ID_GENERATE causing an unique id to
422 * be automatically generated and assigned.
423 *
424 * Either a doit or dumpit callback must be specified for every registered
425 * operation or the function will fail. Only one operation structure per
426 * command identifier may be registered.
427 *
428 * See include/net/genetlink.h for more documenation on the operations
429 * structure.
430 *
431 * This is equivalent to calling genl_register_family() followed by
432 * genl_register_ops() for every operation entry in the table taking
433 * care to unregister the family on error path.
434 *
435 * Return 0 on success or a negative error code.
436 */
437int genl_register_family_with_ops(struct genl_family *family,
438 struct genl_ops *ops, size_t n_ops)
439{
440 int err, i;
441
442 err = genl_register_family(family);
443 if (err)
444 return err;
445
446 for (i = 0; i < n_ops; ++i, ++ops) {
447 err = genl_register_ops(family, ops);
448 if (err)
449 goto err_out;
450 }
451 return 0;
452err_out:
453 genl_unregister_family(family);
454 return err;
455}
456EXPORT_SYMBOL(genl_register_family_with_ops);
457
458/**
459 * genl_unregister_family - unregister generic netlink family
460 * @family: generic netlink family
461 *
462 * Unregisters the specified family.
463 *
464 * Returns 0 on success or a negative error code.
465 */
466int genl_unregister_family(struct genl_family *family)
467{
468 struct genl_family *rc;
469
470 genl_lock();
471
472 genl_unregister_mc_groups(family);
473
474 list_for_each_entry(rc, genl_family_chain(family->id), family_list) {
475 if (family->id != rc->id || strcmp(rc->name, family->name))
476 continue;
477
478 list_del(&rc->family_list);
479 INIT_LIST_HEAD(&family->ops_list);
480 genl_unlock();
481
482 kfree(family->attrbuf);
483 genl_ctrl_event(CTRL_CMD_DELFAMILY, family);
484 return 0;
485 }
486
487 genl_unlock();
488
489 return -ENOENT;
490}
491EXPORT_SYMBOL(genl_unregister_family);
492
493static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
494{
495 struct genl_ops *ops;
496 struct genl_family *family;
497 struct net *net = sock_net(skb->sk);
498 struct genl_info info;
499 struct genlmsghdr *hdr = nlmsg_data(nlh);
500 int hdrlen, err;
501
502 family = genl_family_find_byid(nlh->nlmsg_type);
503 if (family == NULL)
504 return -ENOENT;
505
506 /* this family doesn't exist in this netns */
507 if (!family->netnsok && !net_eq(net, &init_net))
508 return -ENOENT;
509
510 hdrlen = GENL_HDRLEN + family->hdrsize;
511 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
512 return -EINVAL;
513
514 ops = genl_get_cmd(hdr->cmd, family);
515 if (ops == NULL)
516 return -EOPNOTSUPP;
517
518 if ((ops->flags & GENL_ADMIN_PERM) &&
519 security_netlink_recv(skb, CAP_NET_ADMIN))
520 return -EPERM;
521
522 if (nlh->nlmsg_flags & NLM_F_DUMP) {
523 if (ops->dumpit == NULL)
524 return -EOPNOTSUPP;
525
526 genl_unlock();
527 err = netlink_dump_start(net->genl_sock, skb, nlh,
528 ops->dumpit, ops->done, 0);
529 genl_lock();
530 return err;
531 }
532
533 if (ops->doit == NULL)
534 return -EOPNOTSUPP;
535
536 if (family->attrbuf) {
537 err = nlmsg_parse(nlh, hdrlen, family->attrbuf, family->maxattr,
538 ops->policy);
539 if (err < 0)
540 return err;
541 }
542
543 info.snd_seq = nlh->nlmsg_seq;
544 info.snd_pid = NETLINK_CB(skb).pid;
545 info.nlhdr = nlh;
546 info.genlhdr = nlmsg_data(nlh);
547 info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
548 info.attrs = family->attrbuf;
549 genl_info_net_set(&info, net);
550 memset(&info.user_ptr, 0, sizeof(info.user_ptr));
551
552 if (family->pre_doit) {
553 err = family->pre_doit(ops, skb, &info);
554 if (err)
555 return err;
556 }
557
558 err = ops->doit(skb, &info);
559
560 if (family->post_doit)
561 family->post_doit(ops, skb, &info);
562
563 return err;
564}
565
566static void genl_rcv(struct sk_buff *skb)
567{
568 genl_lock();
569 netlink_rcv_skb(skb, &genl_rcv_msg);
570 genl_unlock();
571}
572
573/**************************************************************************
574 * Controller
575 **************************************************************************/
576
577static struct genl_family genl_ctrl = {
578 .id = GENL_ID_CTRL,
579 .name = "nlctrl",
580 .version = 0x2,
581 .maxattr = CTRL_ATTR_MAX,
582 .netnsok = true,
583};
584
585static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
586 u32 flags, struct sk_buff *skb, u8 cmd)
587{
588 void *hdr;
589
590 hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
591 if (hdr == NULL)
592 return -1;
593
594 NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, family->name);
595 NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, family->id);
596 NLA_PUT_U32(skb, CTRL_ATTR_VERSION, family->version);
597 NLA_PUT_U32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize);
598 NLA_PUT_U32(skb, CTRL_ATTR_MAXATTR, family->maxattr);
599
600 if (!list_empty(&family->ops_list)) {
601 struct nlattr *nla_ops;
602 struct genl_ops *ops;
603 int idx = 1;
604
605 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
606 if (nla_ops == NULL)
607 goto nla_put_failure;
608
609 list_for_each_entry(ops, &family->ops_list, ops_list) {
610 struct nlattr *nest;
611
612 nest = nla_nest_start(skb, idx++);
613 if (nest == NULL)
614 goto nla_put_failure;
615
616 NLA_PUT_U32(skb, CTRL_ATTR_OP_ID, ops->cmd);
617 NLA_PUT_U32(skb, CTRL_ATTR_OP_FLAGS, ops->flags);
618
619 nla_nest_end(skb, nest);
620 }
621
622 nla_nest_end(skb, nla_ops);
623 }
624
625 if (!list_empty(&family->mcast_groups)) {
626 struct genl_multicast_group *grp;
627 struct nlattr *nla_grps;
628 int idx = 1;
629
630 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
631 if (nla_grps == NULL)
632 goto nla_put_failure;
633
634 list_for_each_entry(grp, &family->mcast_groups, list) {
635 struct nlattr *nest;
636
637 nest = nla_nest_start(skb, idx++);
638 if (nest == NULL)
639 goto nla_put_failure;
640
641 NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
642 NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
643 grp->name);
644
645 nla_nest_end(skb, nest);
646 }
647 nla_nest_end(skb, nla_grps);
648 }
649
650 return genlmsg_end(skb, hdr);
651
652nla_put_failure:
653 genlmsg_cancel(skb, hdr);
654 return -EMSGSIZE;
655}
656
657static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 pid,
658 u32 seq, u32 flags, struct sk_buff *skb,
659 u8 cmd)
660{
661 void *hdr;
662 struct nlattr *nla_grps;
663 struct nlattr *nest;
664
665 hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
666 if (hdr == NULL)
667 return -1;
668
669 NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, grp->family->name);
670 NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, grp->family->id);
671
672 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
673 if (nla_grps == NULL)
674 goto nla_put_failure;
675
676 nest = nla_nest_start(skb, 1);
677 if (nest == NULL)
678 goto nla_put_failure;
679
680 NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
681 NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
682 grp->name);
683
684 nla_nest_end(skb, nest);
685 nla_nest_end(skb, nla_grps);
686
687 return genlmsg_end(skb, hdr);
688
689nla_put_failure:
690 genlmsg_cancel(skb, hdr);
691 return -EMSGSIZE;
692}
693
694static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
695{
696
697 int i, n = 0;
698 struct genl_family *rt;
699 struct net *net = sock_net(skb->sk);
700 int chains_to_skip = cb->args[0];
701 int fams_to_skip = cb->args[1];
702
703 for (i = chains_to_skip; i < GENL_FAM_TAB_SIZE; i++) {
704 n = 0;
705 list_for_each_entry(rt, genl_family_chain(i), family_list) {
706 if (!rt->netnsok && !net_eq(net, &init_net))
707 continue;
708 if (++n < fams_to_skip)
709 continue;
710 if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).pid,
711 cb->nlh->nlmsg_seq, NLM_F_MULTI,
712 skb, CTRL_CMD_NEWFAMILY) < 0)
713 goto errout;
714 }
715
716 fams_to_skip = 0;
717 }
718
719errout:
720 cb->args[0] = i;
721 cb->args[1] = n;
722
723 return skb->len;
724}
725
726static struct sk_buff *ctrl_build_family_msg(struct genl_family *family,
727 u32 pid, int seq, u8 cmd)
728{
729 struct sk_buff *skb;
730 int err;
731
732 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
733 if (skb == NULL)
734 return ERR_PTR(-ENOBUFS);
735
736 err = ctrl_fill_info(family, pid, seq, 0, skb, cmd);
737 if (err < 0) {
738 nlmsg_free(skb);
739 return ERR_PTR(err);
740 }
741
742 return skb;
743}
744
745static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_multicast_group *grp,
746 u32 pid, int seq, u8 cmd)
747{
748 struct sk_buff *skb;
749 int err;
750
751 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
752 if (skb == NULL)
753 return ERR_PTR(-ENOBUFS);
754
755 err = ctrl_fill_mcgrp_info(grp, pid, seq, 0, skb, cmd);
756 if (err < 0) {
757 nlmsg_free(skb);
758 return ERR_PTR(err);
759 }
760
761 return skb;
762}
763
764static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
765 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 },
766 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
767 .len = GENL_NAMSIZ - 1 },
768};
769
770static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
771{
772 struct sk_buff *msg;
773 struct genl_family *res = NULL;
774 int err = -EINVAL;
775
776 if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
777 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
778 res = genl_family_find_byid(id);
779 err = -ENOENT;
780 }
781
782 if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
783 char *name;
784
785 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
786 res = genl_family_find_byname(name);
787 err = -ENOENT;
788 }
789
790 if (res == NULL)
791 return err;
792
793 if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) {
794 /* family doesn't exist here */
795 return -ENOENT;
796 }
797
798 msg = ctrl_build_family_msg(res, info->snd_pid, info->snd_seq,
799 CTRL_CMD_NEWFAMILY);
800 if (IS_ERR(msg))
801 return PTR_ERR(msg);
802
803 return genlmsg_reply(msg, info);
804}
805
806static int genl_ctrl_event(int event, void *data)
807{
808 struct sk_buff *msg;
809 struct genl_family *family;
810 struct genl_multicast_group *grp;
811
812 /* genl is still initialising */
813 if (!init_net.genl_sock)
814 return 0;
815
816 switch (event) {
817 case CTRL_CMD_NEWFAMILY:
818 case CTRL_CMD_DELFAMILY:
819 family = data;
820 msg = ctrl_build_family_msg(family, 0, 0, event);
821 break;
822 case CTRL_CMD_NEWMCAST_GRP:
823 case CTRL_CMD_DELMCAST_GRP:
824 grp = data;
825 family = grp->family;
826 msg = ctrl_build_mcgrp_msg(data, 0, 0, event);
827 break;
828 default:
829 return -EINVAL;
830 }
831
832 if (IS_ERR(msg))
833 return PTR_ERR(msg);
834
835 if (!family->netnsok) {
836 genlmsg_multicast_netns(&init_net, msg, 0,
837 GENL_ID_CTRL, GFP_KERNEL);
838 } else {
839 rcu_read_lock();
840 genlmsg_multicast_allns(msg, 0, GENL_ID_CTRL, GFP_ATOMIC);
841 rcu_read_unlock();
842 }
843
844 return 0;
845}
846
847static struct genl_ops genl_ctrl_ops = {
848 .cmd = CTRL_CMD_GETFAMILY,
849 .doit = ctrl_getfamily,
850 .dumpit = ctrl_dumpfamily,
851 .policy = ctrl_policy,
852};
853
854static struct genl_multicast_group notify_grp = {
855 .name = "notify",
856};
857
858static int __net_init genl_pernet_init(struct net *net)
859{
860 /* we'll bump the group number right afterwards */
861 net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, 0,
862 genl_rcv, &genl_mutex,
863 THIS_MODULE);
864
865 if (!net->genl_sock && net_eq(net, &init_net))
866 panic("GENL: Cannot initialize generic netlink\n");
867
868 if (!net->genl_sock)
869 return -ENOMEM;
870
871 return 0;
872}
873
874static void __net_exit genl_pernet_exit(struct net *net)
875{
876 netlink_kernel_release(net->genl_sock);
877 net->genl_sock = NULL;
878}
879
880static struct pernet_operations genl_pernet_ops = {
881 .init = genl_pernet_init,
882 .exit = genl_pernet_exit,
883};
884
885static int __init genl_init(void)
886{
887 int i, err;
888
889 for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
890 INIT_LIST_HEAD(&family_ht[i]);
891
892 err = genl_register_family_with_ops(&genl_ctrl, &genl_ctrl_ops, 1);
893 if (err < 0)
894 goto problem;
895
896 netlink_set_nonroot(NETLINK_GENERIC, NL_NONROOT_RECV);
897
898 err = register_pernet_subsys(&genl_pernet_ops);
899 if (err)
900 goto problem;
901
902 err = genl_register_mc_group(&genl_ctrl, ¬ify_grp);
903 if (err < 0)
904 goto problem;
905
906 return 0;
907
908problem:
909 panic("GENL: Cannot register controller: %d\n", err);
910}
911
912subsys_initcall(genl_init);
913
914static int genlmsg_mcast(struct sk_buff *skb, u32 pid, unsigned long group,
915 gfp_t flags)
916{
917 struct sk_buff *tmp;
918 struct net *net, *prev = NULL;
919 int err;
920
921 for_each_net_rcu(net) {
922 if (prev) {
923 tmp = skb_clone(skb, flags);
924 if (!tmp) {
925 err = -ENOMEM;
926 goto error;
927 }
928 err = nlmsg_multicast(prev->genl_sock, tmp,
929 pid, group, flags);
930 if (err)
931 goto error;
932 }
933
934 prev = net;
935 }
936
937 return nlmsg_multicast(prev->genl_sock, skb, pid, group, flags);
938 error:
939 kfree_skb(skb);
940 return err;
941}
942
943int genlmsg_multicast_allns(struct sk_buff *skb, u32 pid, unsigned int group,
944 gfp_t flags)
945{
946 return genlmsg_mcast(skb, pid, group, flags);
947}
948EXPORT_SYMBOL(genlmsg_multicast_allns);