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 int genl_get_cmd_cnt(const struct genl_family *family)
111{
112 return family->n_ops + family->n_small_ops;
113}
114
115static void genl_op_from_full(const struct genl_family *family,
116 unsigned int i, struct genl_ops *op)
117{
118 *op = family->ops[i];
119
120 if (!op->maxattr)
121 op->maxattr = family->maxattr;
122 if (!op->policy)
123 op->policy = family->policy;
124}
125
126static int genl_get_cmd_full(u32 cmd, const struct genl_family *family,
127 struct genl_ops *op)
128{
129 int i;
130
131 for (i = 0; i < family->n_ops; i++)
132 if (family->ops[i].cmd == cmd) {
133 genl_op_from_full(family, i, op);
134 return 0;
135 }
136
137 return -ENOENT;
138}
139
140static void genl_op_from_small(const struct genl_family *family,
141 unsigned int i, struct genl_ops *op)
142{
143 memset(op, 0, sizeof(*op));
144 op->doit = family->small_ops[i].doit;
145 op->dumpit = family->small_ops[i].dumpit;
146 op->cmd = family->small_ops[i].cmd;
147 op->internal_flags = family->small_ops[i].internal_flags;
148 op->flags = family->small_ops[i].flags;
149 op->validate = family->small_ops[i].validate;
150
151 op->maxattr = family->maxattr;
152 op->policy = family->policy;
153}
154
155static int genl_get_cmd_small(u32 cmd, const struct genl_family *family,
156 struct genl_ops *op)
157{
158 int i;
159
160 for (i = 0; i < family->n_small_ops; i++)
161 if (family->small_ops[i].cmd == cmd) {
162 genl_op_from_small(family, i, op);
163 return 0;
164 }
165
166 return -ENOENT;
167}
168
169static int genl_get_cmd(u32 cmd, const struct genl_family *family,
170 struct genl_ops *op)
171{
172 if (!genl_get_cmd_full(cmd, family, op))
173 return 0;
174 return genl_get_cmd_small(cmd, family, op);
175}
176
177static void genl_get_cmd_by_index(unsigned int i,
178 const struct genl_family *family,
179 struct genl_ops *op)
180{
181 if (i < family->n_ops)
182 genl_op_from_full(family, i, op);
183 else if (i < family->n_ops + family->n_small_ops)
184 genl_op_from_small(family, i - family->n_ops, op);
185 else
186 WARN_ON_ONCE(1);
187}
188
189static int genl_allocate_reserve_groups(int n_groups, int *first_id)
190{
191 unsigned long *new_groups;
192 int start = 0;
193 int i;
194 int id;
195 bool fits;
196
197 do {
198 if (start == 0)
199 id = find_first_zero_bit(mc_groups,
200 mc_groups_longs *
201 BITS_PER_LONG);
202 else
203 id = find_next_zero_bit(mc_groups,
204 mc_groups_longs * BITS_PER_LONG,
205 start);
206
207 fits = true;
208 for (i = id;
209 i < min_t(int, id + n_groups,
210 mc_groups_longs * BITS_PER_LONG);
211 i++) {
212 if (test_bit(i, mc_groups)) {
213 start = i;
214 fits = false;
215 break;
216 }
217 }
218
219 if (id + n_groups > mc_groups_longs * BITS_PER_LONG) {
220 unsigned long new_longs = mc_groups_longs +
221 BITS_TO_LONGS(n_groups);
222 size_t nlen = new_longs * sizeof(unsigned long);
223
224 if (mc_groups == &mc_group_start) {
225 new_groups = kzalloc(nlen, GFP_KERNEL);
226 if (!new_groups)
227 return -ENOMEM;
228 mc_groups = new_groups;
229 *mc_groups = mc_group_start;
230 } else {
231 new_groups = krealloc(mc_groups, nlen,
232 GFP_KERNEL);
233 if (!new_groups)
234 return -ENOMEM;
235 mc_groups = new_groups;
236 for (i = 0; i < BITS_TO_LONGS(n_groups); i++)
237 mc_groups[mc_groups_longs + i] = 0;
238 }
239 mc_groups_longs = new_longs;
240 }
241 } while (!fits);
242
243 for (i = id; i < id + n_groups; i++)
244 set_bit(i, mc_groups);
245 *first_id = id;
246 return 0;
247}
248
249static struct genl_family genl_ctrl;
250
251static int genl_validate_assign_mc_groups(struct genl_family *family)
252{
253 int first_id;
254 int n_groups = family->n_mcgrps;
255 int err = 0, i;
256 bool groups_allocated = false;
257
258 if (!n_groups)
259 return 0;
260
261 for (i = 0; i < n_groups; i++) {
262 const struct genl_multicast_group *grp = &family->mcgrps[i];
263
264 if (WARN_ON(grp->name[0] == '\0'))
265 return -EINVAL;
266 if (WARN_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL))
267 return -EINVAL;
268 }
269
270 /* special-case our own group and hacks */
271 if (family == &genl_ctrl) {
272 first_id = GENL_ID_CTRL;
273 BUG_ON(n_groups != 1);
274 } else if (strcmp(family->name, "NET_DM") == 0) {
275 first_id = 1;
276 BUG_ON(n_groups != 1);
277 } else if (family->id == GENL_ID_VFS_DQUOT) {
278 first_id = GENL_ID_VFS_DQUOT;
279 BUG_ON(n_groups != 1);
280 } else if (family->id == GENL_ID_PMCRAID) {
281 first_id = GENL_ID_PMCRAID;
282 BUG_ON(n_groups != 1);
283 } else {
284 groups_allocated = true;
285 err = genl_allocate_reserve_groups(n_groups, &first_id);
286 if (err)
287 return err;
288 }
289
290 family->mcgrp_offset = first_id;
291
292 /* if still initializing, can't and don't need to realloc bitmaps */
293 if (!init_net.genl_sock)
294 return 0;
295
296 if (family->netnsok) {
297 struct net *net;
298
299 netlink_table_grab();
300 rcu_read_lock();
301 for_each_net_rcu(net) {
302 err = __netlink_change_ngroups(net->genl_sock,
303 mc_groups_longs * BITS_PER_LONG);
304 if (err) {
305 /*
306 * No need to roll back, can only fail if
307 * memory allocation fails and then the
308 * number of _possible_ groups has been
309 * increased on some sockets which is ok.
310 */
311 break;
312 }
313 }
314 rcu_read_unlock();
315 netlink_table_ungrab();
316 } else {
317 err = netlink_change_ngroups(init_net.genl_sock,
318 mc_groups_longs * BITS_PER_LONG);
319 }
320
321 if (groups_allocated && err) {
322 for (i = 0; i < family->n_mcgrps; i++)
323 clear_bit(family->mcgrp_offset + i, mc_groups);
324 }
325
326 return err;
327}
328
329static void genl_unregister_mc_groups(const struct genl_family *family)
330{
331 struct net *net;
332 int i;
333
334 netlink_table_grab();
335 rcu_read_lock();
336 for_each_net_rcu(net) {
337 for (i = 0; i < family->n_mcgrps; i++)
338 __netlink_clear_multicast_users(
339 net->genl_sock, family->mcgrp_offset + i);
340 }
341 rcu_read_unlock();
342 netlink_table_ungrab();
343
344 for (i = 0; i < family->n_mcgrps; i++) {
345 int grp_id = family->mcgrp_offset + i;
346
347 if (grp_id != 1)
348 clear_bit(grp_id, mc_groups);
349 genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, family,
350 &family->mcgrps[i], grp_id);
351 }
352}
353
354static int genl_validate_ops(const struct genl_family *family)
355{
356 int i, j;
357
358 if (WARN_ON(family->n_ops && !family->ops) ||
359 WARN_ON(family->n_small_ops && !family->small_ops))
360 return -EINVAL;
361
362 for (i = 0; i < genl_get_cmd_cnt(family); i++) {
363 struct genl_ops op;
364
365 genl_get_cmd_by_index(i, family, &op);
366 if (op.dumpit == NULL && op.doit == NULL)
367 return -EINVAL;
368 for (j = i + 1; j < genl_get_cmd_cnt(family); j++) {
369 struct genl_ops op2;
370
371 genl_get_cmd_by_index(j, family, &op2);
372 if (op.cmd == op2.cmd)
373 return -EINVAL;
374 }
375 }
376
377 return 0;
378}
379
380/**
381 * genl_register_family - register a generic netlink family
382 * @family: generic netlink family
383 *
384 * Registers the specified family after validating it first. Only one
385 * family may be registered with the same family name or identifier.
386 *
387 * The family's ops, multicast groups and module pointer must already
388 * be assigned.
389 *
390 * Return 0 on success or a negative error code.
391 */
392int genl_register_family(struct genl_family *family)
393{
394 int err, i;
395 int start = GENL_START_ALLOC, end = GENL_MAX_ID;
396
397 err = genl_validate_ops(family);
398 if (err)
399 return err;
400
401 genl_lock_all();
402
403 if (genl_family_find_byname(family->name)) {
404 err = -EEXIST;
405 goto errout_locked;
406 }
407
408 /*
409 * Sadly, a few cases need to be special-cased
410 * due to them having previously abused the API
411 * and having used their family ID also as their
412 * multicast group ID, so we use reserved IDs
413 * for both to be sure we can do that mapping.
414 */
415 if (family == &genl_ctrl) {
416 /* and this needs to be special for initial family lookups */
417 start = end = GENL_ID_CTRL;
418 } else if (strcmp(family->name, "pmcraid") == 0) {
419 start = end = GENL_ID_PMCRAID;
420 } else if (strcmp(family->name, "VFS_DQUOT") == 0) {
421 start = end = GENL_ID_VFS_DQUOT;
422 }
423
424 family->id = idr_alloc_cyclic(&genl_fam_idr, family,
425 start, end + 1, GFP_KERNEL);
426 if (family->id < 0) {
427 err = family->id;
428 goto errout_locked;
429 }
430
431 err = genl_validate_assign_mc_groups(family);
432 if (err)
433 goto errout_remove;
434
435 genl_unlock_all();
436
437 /* send all events */
438 genl_ctrl_event(CTRL_CMD_NEWFAMILY, family, NULL, 0);
439 for (i = 0; i < family->n_mcgrps; i++)
440 genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, family,
441 &family->mcgrps[i], family->mcgrp_offset + i);
442
443 return 0;
444
445errout_remove:
446 idr_remove(&genl_fam_idr, family->id);
447errout_locked:
448 genl_unlock_all();
449 return err;
450}
451EXPORT_SYMBOL(genl_register_family);
452
453/**
454 * genl_unregister_family - unregister generic netlink family
455 * @family: generic netlink family
456 *
457 * Unregisters the specified family.
458 *
459 * Returns 0 on success or a negative error code.
460 */
461int genl_unregister_family(const struct genl_family *family)
462{
463 genl_lock_all();
464
465 if (!genl_family_find_byid(family->id)) {
466 genl_unlock_all();
467 return -ENOENT;
468 }
469
470 genl_unregister_mc_groups(family);
471
472 idr_remove(&genl_fam_idr, family->id);
473
474 up_write(&cb_lock);
475 wait_event(genl_sk_destructing_waitq,
476 atomic_read(&genl_sk_destructing_cnt) == 0);
477 genl_unlock();
478
479 genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 0);
480
481 return 0;
482}
483EXPORT_SYMBOL(genl_unregister_family);
484
485/**
486 * genlmsg_put - Add generic netlink header to netlink message
487 * @skb: socket buffer holding the message
488 * @portid: netlink portid the message is addressed to
489 * @seq: sequence number (usually the one of the sender)
490 * @family: generic netlink family
491 * @flags: netlink message flags
492 * @cmd: generic netlink command
493 *
494 * Returns pointer to user specific header
495 */
496void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
497 const struct genl_family *family, int flags, u8 cmd)
498{
499 struct nlmsghdr *nlh;
500 struct genlmsghdr *hdr;
501
502 nlh = nlmsg_put(skb, portid, seq, family->id, GENL_HDRLEN +
503 family->hdrsize, flags);
504 if (nlh == NULL)
505 return NULL;
506
507 hdr = nlmsg_data(nlh);
508 hdr->cmd = cmd;
509 hdr->version = family->version;
510 hdr->reserved = 0;
511
512 return (char *) hdr + GENL_HDRLEN;
513}
514EXPORT_SYMBOL(genlmsg_put);
515
516static struct genl_dumpit_info *genl_dumpit_info_alloc(void)
517{
518 return kmalloc(sizeof(struct genl_dumpit_info), GFP_KERNEL);
519}
520
521static void genl_dumpit_info_free(const struct genl_dumpit_info *info)
522{
523 kfree(info);
524}
525
526static struct nlattr **
527genl_family_rcv_msg_attrs_parse(const struct genl_family *family,
528 struct nlmsghdr *nlh,
529 struct netlink_ext_ack *extack,
530 const struct genl_ops *ops,
531 int hdrlen,
532 enum genl_validate_flags no_strict_flag)
533{
534 enum netlink_validation validate = ops->validate & no_strict_flag ?
535 NL_VALIDATE_LIBERAL :
536 NL_VALIDATE_STRICT;
537 struct nlattr **attrbuf;
538 int err;
539
540 if (!ops->maxattr)
541 return NULL;
542
543 attrbuf = kmalloc_array(ops->maxattr + 1,
544 sizeof(struct nlattr *), GFP_KERNEL);
545 if (!attrbuf)
546 return ERR_PTR(-ENOMEM);
547
548 err = __nlmsg_parse(nlh, hdrlen, attrbuf, ops->maxattr, ops->policy,
549 validate, extack);
550 if (err) {
551 kfree(attrbuf);
552 return ERR_PTR(err);
553 }
554 return attrbuf;
555}
556
557static void genl_family_rcv_msg_attrs_free(struct nlattr **attrbuf)
558{
559 kfree(attrbuf);
560}
561
562struct genl_start_context {
563 const struct genl_family *family;
564 struct nlmsghdr *nlh;
565 struct netlink_ext_ack *extack;
566 const struct genl_ops *ops;
567 int hdrlen;
568};
569
570static int genl_start(struct netlink_callback *cb)
571{
572 struct genl_start_context *ctx = cb->data;
573 const struct genl_ops *ops = ctx->ops;
574 struct genl_dumpit_info *info;
575 struct nlattr **attrs = NULL;
576 int rc = 0;
577
578 if (ops->validate & GENL_DONT_VALIDATE_DUMP)
579 goto no_attrs;
580
581 if (ctx->nlh->nlmsg_len < nlmsg_msg_size(ctx->hdrlen))
582 return -EINVAL;
583
584 attrs = genl_family_rcv_msg_attrs_parse(ctx->family, ctx->nlh, ctx->extack,
585 ops, ctx->hdrlen,
586 GENL_DONT_VALIDATE_DUMP_STRICT);
587 if (IS_ERR(attrs))
588 return PTR_ERR(attrs);
589
590no_attrs:
591 info = genl_dumpit_info_alloc();
592 if (!info) {
593 genl_family_rcv_msg_attrs_free(attrs);
594 return -ENOMEM;
595 }
596 info->family = ctx->family;
597 info->op = *ops;
598 info->attrs = attrs;
599
600 cb->data = info;
601 if (ops->start) {
602 if (!ctx->family->parallel_ops)
603 genl_lock();
604 rc = ops->start(cb);
605 if (!ctx->family->parallel_ops)
606 genl_unlock();
607 }
608
609 if (rc) {
610 genl_family_rcv_msg_attrs_free(info->attrs);
611 genl_dumpit_info_free(info);
612 cb->data = NULL;
613 }
614 return rc;
615}
616
617static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
618{
619 const struct genl_ops *ops = &genl_dumpit_info(cb)->op;
620 int rc;
621
622 genl_lock();
623 rc = ops->dumpit(skb, cb);
624 genl_unlock();
625 return rc;
626}
627
628static int genl_lock_done(struct netlink_callback *cb)
629{
630 const struct genl_dumpit_info *info = genl_dumpit_info(cb);
631 const struct genl_ops *ops = &info->op;
632 int rc = 0;
633
634 if (ops->done) {
635 genl_lock();
636 rc = ops->done(cb);
637 genl_unlock();
638 }
639 genl_family_rcv_msg_attrs_free(info->attrs);
640 genl_dumpit_info_free(info);
641 return rc;
642}
643
644static int genl_parallel_done(struct netlink_callback *cb)
645{
646 const struct genl_dumpit_info *info = genl_dumpit_info(cb);
647 const struct genl_ops *ops = &info->op;
648 int rc = 0;
649
650 if (ops->done)
651 rc = ops->done(cb);
652 genl_family_rcv_msg_attrs_free(info->attrs);
653 genl_dumpit_info_free(info);
654 return rc;
655}
656
657static int genl_family_rcv_msg_dumpit(const struct genl_family *family,
658 struct sk_buff *skb,
659 struct nlmsghdr *nlh,
660 struct netlink_ext_ack *extack,
661 const struct genl_ops *ops,
662 int hdrlen, struct net *net)
663{
664 struct genl_start_context ctx;
665 int err;
666
667 if (!ops->dumpit)
668 return -EOPNOTSUPP;
669
670 ctx.family = family;
671 ctx.nlh = nlh;
672 ctx.extack = extack;
673 ctx.ops = ops;
674 ctx.hdrlen = hdrlen;
675
676 if (!family->parallel_ops) {
677 struct netlink_dump_control c = {
678 .module = family->module,
679 .data = &ctx,
680 .start = genl_start,
681 .dump = genl_lock_dumpit,
682 .done = genl_lock_done,
683 };
684
685 genl_unlock();
686 err = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
687 genl_lock();
688 } else {
689 struct netlink_dump_control c = {
690 .module = family->module,
691 .data = &ctx,
692 .start = genl_start,
693 .dump = ops->dumpit,
694 .done = genl_parallel_done,
695 };
696
697 err = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
698 }
699
700 return err;
701}
702
703static int genl_family_rcv_msg_doit(const struct genl_family *family,
704 struct sk_buff *skb,
705 struct nlmsghdr *nlh,
706 struct netlink_ext_ack *extack,
707 const struct genl_ops *ops,
708 int hdrlen, struct net *net)
709{
710 struct nlattr **attrbuf;
711 struct genl_info info;
712 int err;
713
714 if (!ops->doit)
715 return -EOPNOTSUPP;
716
717 attrbuf = genl_family_rcv_msg_attrs_parse(family, nlh, extack,
718 ops, hdrlen,
719 GENL_DONT_VALIDATE_STRICT);
720 if (IS_ERR(attrbuf))
721 return PTR_ERR(attrbuf);
722
723 info.snd_seq = nlh->nlmsg_seq;
724 info.snd_portid = NETLINK_CB(skb).portid;
725 info.nlhdr = nlh;
726 info.genlhdr = nlmsg_data(nlh);
727 info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
728 info.attrs = attrbuf;
729 info.extack = extack;
730 genl_info_net_set(&info, net);
731 memset(&info.user_ptr, 0, sizeof(info.user_ptr));
732
733 if (family->pre_doit) {
734 err = family->pre_doit(ops, skb, &info);
735 if (err)
736 goto out;
737 }
738
739 err = ops->doit(skb, &info);
740
741 if (family->post_doit)
742 family->post_doit(ops, skb, &info);
743
744out:
745 genl_family_rcv_msg_attrs_free(attrbuf);
746
747 return err;
748}
749
750static int genl_family_rcv_msg(const struct genl_family *family,
751 struct sk_buff *skb,
752 struct nlmsghdr *nlh,
753 struct netlink_ext_ack *extack)
754{
755 struct net *net = sock_net(skb->sk);
756 struct genlmsghdr *hdr = nlmsg_data(nlh);
757 struct genl_ops op;
758 int hdrlen;
759
760 /* this family doesn't exist in this netns */
761 if (!family->netnsok && !net_eq(net, &init_net))
762 return -ENOENT;
763
764 hdrlen = GENL_HDRLEN + family->hdrsize;
765 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
766 return -EINVAL;
767
768 if (genl_get_cmd(hdr->cmd, family, &op))
769 return -EOPNOTSUPP;
770
771 if ((op.flags & GENL_ADMIN_PERM) &&
772 !netlink_capable(skb, CAP_NET_ADMIN))
773 return -EPERM;
774
775 if ((op.flags & GENL_UNS_ADMIN_PERM) &&
776 !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
777 return -EPERM;
778
779 if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP)
780 return genl_family_rcv_msg_dumpit(family, skb, nlh, extack,
781 &op, hdrlen, net);
782 else
783 return genl_family_rcv_msg_doit(family, skb, nlh, extack,
784 &op, hdrlen, net);
785}
786
787static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
788 struct netlink_ext_ack *extack)
789{
790 const struct genl_family *family;
791 int err;
792
793 family = genl_family_find_byid(nlh->nlmsg_type);
794 if (family == NULL)
795 return -ENOENT;
796
797 if (!family->parallel_ops)
798 genl_lock();
799
800 err = genl_family_rcv_msg(family, skb, nlh, extack);
801
802 if (!family->parallel_ops)
803 genl_unlock();
804
805 return err;
806}
807
808static void genl_rcv(struct sk_buff *skb)
809{
810 down_read(&cb_lock);
811 netlink_rcv_skb(skb, &genl_rcv_msg);
812 up_read(&cb_lock);
813}
814
815/**************************************************************************
816 * Controller
817 **************************************************************************/
818
819static struct genl_family genl_ctrl;
820
821static int ctrl_fill_info(const struct genl_family *family, u32 portid, u32 seq,
822 u32 flags, struct sk_buff *skb, u8 cmd)
823{
824 void *hdr;
825
826 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
827 if (hdr == NULL)
828 return -1;
829
830 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
831 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) ||
832 nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) ||
833 nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) ||
834 nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr))
835 goto nla_put_failure;
836
837 if (genl_get_cmd_cnt(family)) {
838 struct nlattr *nla_ops;
839 int i;
840
841 nla_ops = nla_nest_start_noflag(skb, CTRL_ATTR_OPS);
842 if (nla_ops == NULL)
843 goto nla_put_failure;
844
845 for (i = 0; i < genl_get_cmd_cnt(family); i++) {
846 struct nlattr *nest;
847 struct genl_ops op;
848 u32 op_flags;
849
850 genl_get_cmd_by_index(i, family, &op);
851 op_flags = op.flags;
852 if (op.dumpit)
853 op_flags |= GENL_CMD_CAP_DUMP;
854 if (op.doit)
855 op_flags |= GENL_CMD_CAP_DO;
856 if (op.policy)
857 op_flags |= GENL_CMD_CAP_HASPOL;
858
859 nest = nla_nest_start_noflag(skb, i + 1);
860 if (nest == NULL)
861 goto nla_put_failure;
862
863 if (nla_put_u32(skb, CTRL_ATTR_OP_ID, op.cmd) ||
864 nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, op_flags))
865 goto nla_put_failure;
866
867 nla_nest_end(skb, nest);
868 }
869
870 nla_nest_end(skb, nla_ops);
871 }
872
873 if (family->n_mcgrps) {
874 struct nlattr *nla_grps;
875 int i;
876
877 nla_grps = nla_nest_start_noflag(skb, CTRL_ATTR_MCAST_GROUPS);
878 if (nla_grps == NULL)
879 goto nla_put_failure;
880
881 for (i = 0; i < family->n_mcgrps; i++) {
882 struct nlattr *nest;
883 const struct genl_multicast_group *grp;
884
885 grp = &family->mcgrps[i];
886
887 nest = nla_nest_start_noflag(skb, i + 1);
888 if (nest == NULL)
889 goto nla_put_failure;
890
891 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID,
892 family->mcgrp_offset + i) ||
893 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
894 grp->name))
895 goto nla_put_failure;
896
897 nla_nest_end(skb, nest);
898 }
899 nla_nest_end(skb, nla_grps);
900 }
901
902 genlmsg_end(skb, hdr);
903 return 0;
904
905nla_put_failure:
906 genlmsg_cancel(skb, hdr);
907 return -EMSGSIZE;
908}
909
910static int ctrl_fill_mcgrp_info(const struct genl_family *family,
911 const struct genl_multicast_group *grp,
912 int grp_id, u32 portid, u32 seq, u32 flags,
913 struct sk_buff *skb, u8 cmd)
914{
915 void *hdr;
916 struct nlattr *nla_grps;
917 struct nlattr *nest;
918
919 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
920 if (hdr == NULL)
921 return -1;
922
923 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
924 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id))
925 goto nla_put_failure;
926
927 nla_grps = nla_nest_start_noflag(skb, CTRL_ATTR_MCAST_GROUPS);
928 if (nla_grps == NULL)
929 goto nla_put_failure;
930
931 nest = nla_nest_start_noflag(skb, 1);
932 if (nest == NULL)
933 goto nla_put_failure;
934
935 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp_id) ||
936 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
937 grp->name))
938 goto nla_put_failure;
939
940 nla_nest_end(skb, nest);
941 nla_nest_end(skb, nla_grps);
942
943 genlmsg_end(skb, hdr);
944 return 0;
945
946nla_put_failure:
947 genlmsg_cancel(skb, hdr);
948 return -EMSGSIZE;
949}
950
951static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
952{
953 int n = 0;
954 struct genl_family *rt;
955 struct net *net = sock_net(skb->sk);
956 int fams_to_skip = cb->args[0];
957 unsigned int id;
958
959 idr_for_each_entry(&genl_fam_idr, rt, id) {
960 if (!rt->netnsok && !net_eq(net, &init_net))
961 continue;
962
963 if (n++ < fams_to_skip)
964 continue;
965
966 if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid,
967 cb->nlh->nlmsg_seq, NLM_F_MULTI,
968 skb, CTRL_CMD_NEWFAMILY) < 0) {
969 n--;
970 break;
971 }
972 }
973
974 cb->args[0] = n;
975 return skb->len;
976}
977
978static struct sk_buff *ctrl_build_family_msg(const struct genl_family *family,
979 u32 portid, int seq, u8 cmd)
980{
981 struct sk_buff *skb;
982 int err;
983
984 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
985 if (skb == NULL)
986 return ERR_PTR(-ENOBUFS);
987
988 err = ctrl_fill_info(family, portid, seq, 0, skb, cmd);
989 if (err < 0) {
990 nlmsg_free(skb);
991 return ERR_PTR(err);
992 }
993
994 return skb;
995}
996
997static struct sk_buff *
998ctrl_build_mcgrp_msg(const struct genl_family *family,
999 const struct genl_multicast_group *grp,
1000 int grp_id, u32 portid, int seq, u8 cmd)
1001{
1002 struct sk_buff *skb;
1003 int err;
1004
1005 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1006 if (skb == NULL)
1007 return ERR_PTR(-ENOBUFS);
1008
1009 err = ctrl_fill_mcgrp_info(family, grp, grp_id, portid,
1010 seq, 0, skb, cmd);
1011 if (err < 0) {
1012 nlmsg_free(skb);
1013 return ERR_PTR(err);
1014 }
1015
1016 return skb;
1017}
1018
1019static const struct nla_policy ctrl_policy_family[] = {
1020 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 },
1021 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
1022 .len = GENL_NAMSIZ - 1 },
1023};
1024
1025static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
1026{
1027 struct sk_buff *msg;
1028 const struct genl_family *res = NULL;
1029 int err = -EINVAL;
1030
1031 if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
1032 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
1033 res = genl_family_find_byid(id);
1034 err = -ENOENT;
1035 }
1036
1037 if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
1038 char *name;
1039
1040 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
1041 res = genl_family_find_byname(name);
1042#ifdef CONFIG_MODULES
1043 if (res == NULL) {
1044 genl_unlock();
1045 up_read(&cb_lock);
1046 request_module("net-pf-%d-proto-%d-family-%s",
1047 PF_NETLINK, NETLINK_GENERIC, name);
1048 down_read(&cb_lock);
1049 genl_lock();
1050 res = genl_family_find_byname(name);
1051 }
1052#endif
1053 err = -ENOENT;
1054 }
1055
1056 if (res == NULL)
1057 return err;
1058
1059 if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) {
1060 /* family doesn't exist here */
1061 return -ENOENT;
1062 }
1063
1064 msg = ctrl_build_family_msg(res, info->snd_portid, info->snd_seq,
1065 CTRL_CMD_NEWFAMILY);
1066 if (IS_ERR(msg))
1067 return PTR_ERR(msg);
1068
1069 return genlmsg_reply(msg, info);
1070}
1071
1072static int genl_ctrl_event(int event, const struct genl_family *family,
1073 const struct genl_multicast_group *grp,
1074 int grp_id)
1075{
1076 struct sk_buff *msg;
1077
1078 /* genl is still initialising */
1079 if (!init_net.genl_sock)
1080 return 0;
1081
1082 switch (event) {
1083 case CTRL_CMD_NEWFAMILY:
1084 case CTRL_CMD_DELFAMILY:
1085 WARN_ON(grp);
1086 msg = ctrl_build_family_msg(family, 0, 0, event);
1087 break;
1088 case CTRL_CMD_NEWMCAST_GRP:
1089 case CTRL_CMD_DELMCAST_GRP:
1090 BUG_ON(!grp);
1091 msg = ctrl_build_mcgrp_msg(family, grp, grp_id, 0, 0, event);
1092 break;
1093 default:
1094 return -EINVAL;
1095 }
1096
1097 if (IS_ERR(msg))
1098 return PTR_ERR(msg);
1099
1100 if (!family->netnsok) {
1101 genlmsg_multicast_netns(&genl_ctrl, &init_net, msg, 0,
1102 0, GFP_KERNEL);
1103 } else {
1104 rcu_read_lock();
1105 genlmsg_multicast_allns(&genl_ctrl, msg, 0,
1106 0, GFP_ATOMIC);
1107 rcu_read_unlock();
1108 }
1109
1110 return 0;
1111}
1112
1113struct ctrl_dump_policy_ctx {
1114 struct netlink_policy_dump_state *state;
1115 const struct genl_family *rt;
1116 unsigned int opidx;
1117 u32 op;
1118 u16 fam_id;
1119 u8 policies:1,
1120 single_op:1;
1121};
1122
1123static const struct nla_policy ctrl_policy_policy[] = {
1124 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 },
1125 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
1126 .len = GENL_NAMSIZ - 1 },
1127 [CTRL_ATTR_OP] = { .type = NLA_U32 },
1128};
1129
1130static int ctrl_dumppolicy_start(struct netlink_callback *cb)
1131{
1132 const struct genl_dumpit_info *info = genl_dumpit_info(cb);
1133 struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
1134 struct nlattr **tb = info->attrs;
1135 const struct genl_family *rt;
1136 struct genl_ops op;
1137 int err, i;
1138
1139 BUILD_BUG_ON(sizeof(*ctx) > sizeof(cb->ctx));
1140
1141 if (!tb[CTRL_ATTR_FAMILY_ID] && !tb[CTRL_ATTR_FAMILY_NAME])
1142 return -EINVAL;
1143
1144 if (tb[CTRL_ATTR_FAMILY_ID]) {
1145 ctx->fam_id = nla_get_u16(tb[CTRL_ATTR_FAMILY_ID]);
1146 } else {
1147 rt = genl_family_find_byname(
1148 nla_data(tb[CTRL_ATTR_FAMILY_NAME]));
1149 if (!rt)
1150 return -ENOENT;
1151 ctx->fam_id = rt->id;
1152 }
1153
1154 rt = genl_family_find_byid(ctx->fam_id);
1155 if (!rt)
1156 return -ENOENT;
1157
1158 ctx->rt = rt;
1159
1160 if (tb[CTRL_ATTR_OP]) {
1161 ctx->single_op = true;
1162 ctx->op = nla_get_u32(tb[CTRL_ATTR_OP]);
1163
1164 err = genl_get_cmd(ctx->op, rt, &op);
1165 if (err) {
1166 NL_SET_BAD_ATTR(cb->extack, tb[CTRL_ATTR_OP]);
1167 return err;
1168 }
1169
1170 if (!op.policy)
1171 return -ENODATA;
1172
1173 return netlink_policy_dump_add_policy(&ctx->state, op.policy,
1174 op.maxattr);
1175 }
1176
1177 for (i = 0; i < genl_get_cmd_cnt(rt); i++) {
1178 genl_get_cmd_by_index(i, rt, &op);
1179
1180 if (op.policy) {
1181 err = netlink_policy_dump_add_policy(&ctx->state,
1182 op.policy,
1183 op.maxattr);
1184 if (err)
1185 return err;
1186 }
1187 }
1188
1189 if (!ctx->state)
1190 return -ENODATA;
1191 return 0;
1192}
1193
1194static void *ctrl_dumppolicy_prep(struct sk_buff *skb,
1195 struct netlink_callback *cb)
1196{
1197 struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
1198 void *hdr;
1199
1200 hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid,
1201 cb->nlh->nlmsg_seq, &genl_ctrl,
1202 NLM_F_MULTI, CTRL_CMD_GETPOLICY);
1203 if (!hdr)
1204 return NULL;
1205
1206 if (nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, ctx->fam_id))
1207 return NULL;
1208
1209 return hdr;
1210}
1211
1212static int ctrl_dumppolicy_put_op(struct sk_buff *skb,
1213 struct netlink_callback *cb,
1214 struct genl_ops *op)
1215{
1216 struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
1217 struct nlattr *nest_pol, *nest_op;
1218 void *hdr;
1219 int idx;
1220
1221 /* skip if we have nothing to show */
1222 if (!op->policy)
1223 return 0;
1224 if (!op->doit &&
1225 (!op->dumpit || op->validate & GENL_DONT_VALIDATE_DUMP))
1226 return 0;
1227
1228 hdr = ctrl_dumppolicy_prep(skb, cb);
1229 if (!hdr)
1230 return -ENOBUFS;
1231
1232 nest_pol = nla_nest_start(skb, CTRL_ATTR_OP_POLICY);
1233 if (!nest_pol)
1234 goto err;
1235
1236 nest_op = nla_nest_start(skb, op->cmd);
1237 if (!nest_op)
1238 goto err;
1239
1240 /* for now both do/dump are always the same */
1241 idx = netlink_policy_dump_get_policy_idx(ctx->state,
1242 op->policy,
1243 op->maxattr);
1244
1245 if (op->doit && nla_put_u32(skb, CTRL_ATTR_POLICY_DO, idx))
1246 goto err;
1247
1248 if (op->dumpit && !(op->validate & GENL_DONT_VALIDATE_DUMP) &&
1249 nla_put_u32(skb, CTRL_ATTR_POLICY_DUMP, idx))
1250 goto err;
1251
1252 nla_nest_end(skb, nest_op);
1253 nla_nest_end(skb, nest_pol);
1254 genlmsg_end(skb, hdr);
1255
1256 return 0;
1257err:
1258 genlmsg_cancel(skb, hdr);
1259 return -ENOBUFS;
1260}
1261
1262static int ctrl_dumppolicy(struct sk_buff *skb, struct netlink_callback *cb)
1263{
1264 struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
1265 void *hdr;
1266
1267 if (!ctx->policies) {
1268 while (ctx->opidx < genl_get_cmd_cnt(ctx->rt)) {
1269 struct genl_ops op;
1270
1271 if (ctx->single_op) {
1272 int err;
1273
1274 err = genl_get_cmd(ctx->op, ctx->rt, &op);
1275 if (WARN_ON(err))
1276 return skb->len;
1277
1278 /* break out of the loop after this one */
1279 ctx->opidx = genl_get_cmd_cnt(ctx->rt);
1280 } else {
1281 genl_get_cmd_by_index(ctx->opidx, ctx->rt, &op);
1282 }
1283
1284 if (ctrl_dumppolicy_put_op(skb, cb, &op))
1285 return skb->len;
1286
1287 ctx->opidx++;
1288 }
1289
1290 /* completed with the per-op policy index list */
1291 ctx->policies = true;
1292 }
1293
1294 while (netlink_policy_dump_loop(ctx->state)) {
1295 struct nlattr *nest;
1296
1297 hdr = ctrl_dumppolicy_prep(skb, cb);
1298 if (!hdr)
1299 goto nla_put_failure;
1300
1301 nest = nla_nest_start(skb, CTRL_ATTR_POLICY);
1302 if (!nest)
1303 goto nla_put_failure;
1304
1305 if (netlink_policy_dump_write(skb, ctx->state))
1306 goto nla_put_failure;
1307
1308 nla_nest_end(skb, nest);
1309
1310 genlmsg_end(skb, hdr);
1311 }
1312
1313 return skb->len;
1314
1315nla_put_failure:
1316 genlmsg_cancel(skb, hdr);
1317 return skb->len;
1318}
1319
1320static int ctrl_dumppolicy_done(struct netlink_callback *cb)
1321{
1322 struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
1323
1324 netlink_policy_dump_free(ctx->state);
1325 return 0;
1326}
1327
1328static const struct genl_ops genl_ctrl_ops[] = {
1329 {
1330 .cmd = CTRL_CMD_GETFAMILY,
1331 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1332 .policy = ctrl_policy_family,
1333 .maxattr = ARRAY_SIZE(ctrl_policy_family) - 1,
1334 .doit = ctrl_getfamily,
1335 .dumpit = ctrl_dumpfamily,
1336 },
1337 {
1338 .cmd = CTRL_CMD_GETPOLICY,
1339 .policy = ctrl_policy_policy,
1340 .maxattr = ARRAY_SIZE(ctrl_policy_policy) - 1,
1341 .start = ctrl_dumppolicy_start,
1342 .dumpit = ctrl_dumppolicy,
1343 .done = ctrl_dumppolicy_done,
1344 },
1345};
1346
1347static const struct genl_multicast_group genl_ctrl_groups[] = {
1348 { .name = "notify", },
1349};
1350
1351static struct genl_family genl_ctrl __ro_after_init = {
1352 .module = THIS_MODULE,
1353 .ops = genl_ctrl_ops,
1354 .n_ops = ARRAY_SIZE(genl_ctrl_ops),
1355 .mcgrps = genl_ctrl_groups,
1356 .n_mcgrps = ARRAY_SIZE(genl_ctrl_groups),
1357 .id = GENL_ID_CTRL,
1358 .name = "nlctrl",
1359 .version = 0x2,
1360 .netnsok = true,
1361};
1362
1363static int genl_bind(struct net *net, int group)
1364{
1365 const struct genl_family *family;
1366 unsigned int id;
1367 int ret = 0;
1368
1369 genl_lock_all();
1370
1371 idr_for_each_entry(&genl_fam_idr, family, id) {
1372 const struct genl_multicast_group *grp;
1373 int i;
1374
1375 if (family->n_mcgrps == 0)
1376 continue;
1377
1378 i = group - family->mcgrp_offset;
1379 if (i < 0 || i >= family->n_mcgrps)
1380 continue;
1381
1382 grp = &family->mcgrps[i];
1383 if ((grp->flags & GENL_UNS_ADMIN_PERM) &&
1384 !ns_capable(net->user_ns, CAP_NET_ADMIN))
1385 ret = -EPERM;
1386
1387 break;
1388 }
1389
1390 genl_unlock_all();
1391 return ret;
1392}
1393
1394static int __net_init genl_pernet_init(struct net *net)
1395{
1396 struct netlink_kernel_cfg cfg = {
1397 .input = genl_rcv,
1398 .flags = NL_CFG_F_NONROOT_RECV,
1399 .bind = genl_bind,
1400 };
1401
1402 /* we'll bump the group number right afterwards */
1403 net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg);
1404
1405 if (!net->genl_sock && net_eq(net, &init_net))
1406 panic("GENL: Cannot initialize generic netlink\n");
1407
1408 if (!net->genl_sock)
1409 return -ENOMEM;
1410
1411 return 0;
1412}
1413
1414static void __net_exit genl_pernet_exit(struct net *net)
1415{
1416 netlink_kernel_release(net->genl_sock);
1417 net->genl_sock = NULL;
1418}
1419
1420static struct pernet_operations genl_pernet_ops = {
1421 .init = genl_pernet_init,
1422 .exit = genl_pernet_exit,
1423};
1424
1425static int __init genl_init(void)
1426{
1427 int err;
1428
1429 err = genl_register_family(&genl_ctrl);
1430 if (err < 0)
1431 goto problem;
1432
1433 err = register_pernet_subsys(&genl_pernet_ops);
1434 if (err)
1435 goto problem;
1436
1437 return 0;
1438
1439problem:
1440 panic("GENL: Cannot register controller: %d\n", err);
1441}
1442
1443core_initcall(genl_init);
1444
1445static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
1446 gfp_t flags)
1447{
1448 struct sk_buff *tmp;
1449 struct net *net, *prev = NULL;
1450 bool delivered = false;
1451 int err;
1452
1453 for_each_net_rcu(net) {
1454 if (prev) {
1455 tmp = skb_clone(skb, flags);
1456 if (!tmp) {
1457 err = -ENOMEM;
1458 goto error;
1459 }
1460 err = nlmsg_multicast(prev->genl_sock, tmp,
1461 portid, group, flags);
1462 if (!err)
1463 delivered = true;
1464 else if (err != -ESRCH)
1465 goto error;
1466 }
1467
1468 prev = net;
1469 }
1470
1471 err = nlmsg_multicast(prev->genl_sock, skb, portid, group, flags);
1472 if (!err)
1473 delivered = true;
1474 else if (err != -ESRCH)
1475 return err;
1476 return delivered ? 0 : -ESRCH;
1477 error:
1478 kfree_skb(skb);
1479 return err;
1480}
1481
1482int genlmsg_multicast_allns(const struct genl_family *family,
1483 struct sk_buff *skb, u32 portid,
1484 unsigned int group, gfp_t flags)
1485{
1486 if (WARN_ON_ONCE(group >= family->n_mcgrps))
1487 return -EINVAL;
1488 group = family->mcgrp_offset + group;
1489 return genlmsg_mcast(skb, portid, group, flags);
1490}
1491EXPORT_SYMBOL(genlmsg_multicast_allns);
1492
1493void genl_notify(const struct genl_family *family, struct sk_buff *skb,
1494 struct genl_info *info, u32 group, gfp_t flags)
1495{
1496 struct net *net = genl_info_net(info);
1497 struct sock *sk = net->genl_sock;
1498 int report = 0;
1499
1500 if (info->nlhdr)
1501 report = nlmsg_report(info->nlhdr);
1502
1503 if (WARN_ON_ONCE(group >= family->n_mcgrps))
1504 return;
1505 group = family->mcgrp_offset + group;
1506 nlmsg_notify(sk, skb, info->snd_portid, group, report, flags);
1507}
1508EXPORT_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#ifdef CONFIG_PROVE_LOCKING
37int lockdep_genl_is_held(void)
38{
39 return lockdep_is_held(&genl_mutex);
40}
41EXPORT_SYMBOL(lockdep_genl_is_held);
42#endif
43
44#define GENL_FAM_TAB_SIZE 16
45#define GENL_FAM_TAB_MASK (GENL_FAM_TAB_SIZE - 1)
46
47static struct list_head family_ht[GENL_FAM_TAB_SIZE];
48/*
49 * Bitmap of multicast groups that are currently in use.
50 *
51 * To avoid an allocation at boot of just one unsigned long,
52 * declare it global instead.
53 * Bit 0 is marked as already used since group 0 is invalid.
54 */
55static unsigned long mc_group_start = 0x1;
56static unsigned long *mc_groups = &mc_group_start;
57static unsigned long mc_groups_longs = 1;
58
59static int genl_ctrl_event(int event, void *data);
60
61static inline unsigned int genl_family_hash(unsigned int id)
62{
63 return id & GENL_FAM_TAB_MASK;
64}
65
66static inline struct list_head *genl_family_chain(unsigned int id)
67{
68 return &family_ht[genl_family_hash(id)];
69}
70
71static struct genl_family *genl_family_find_byid(unsigned int id)
72{
73 struct genl_family *f;
74
75 list_for_each_entry(f, genl_family_chain(id), family_list)
76 if (f->id == id)
77 return f;
78
79 return NULL;
80}
81
82static struct genl_family *genl_family_find_byname(char *name)
83{
84 struct genl_family *f;
85 int i;
86
87 for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
88 list_for_each_entry(f, genl_family_chain(i), family_list)
89 if (strcmp(f->name, name) == 0)
90 return f;
91
92 return NULL;
93}
94
95static struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family)
96{
97 struct genl_ops *ops;
98
99 list_for_each_entry(ops, &family->ops_list, ops_list)
100 if (ops->cmd == cmd)
101 return ops;
102
103 return NULL;
104}
105
106/* Of course we are going to have problems once we hit
107 * 2^16 alive types, but that can only happen by year 2K
108*/
109static u16 genl_generate_id(void)
110{
111 static u16 id_gen_idx = GENL_MIN_ID;
112 int i;
113
114 for (i = 0; i <= GENL_MAX_ID - GENL_MIN_ID; i++) {
115 if (!genl_family_find_byid(id_gen_idx))
116 return id_gen_idx;
117 if (++id_gen_idx > GENL_MAX_ID)
118 id_gen_idx = GENL_MIN_ID;
119 }
120
121 return 0;
122}
123
124static struct genl_multicast_group notify_grp;
125
126/**
127 * genl_register_mc_group - register a multicast group
128 *
129 * Registers the specified multicast group and notifies userspace
130 * about the new group.
131 *
132 * Returns 0 on success or a negative error code.
133 *
134 * @family: The generic netlink family the group shall be registered for.
135 * @grp: The group to register, must have a name.
136 */
137int genl_register_mc_group(struct genl_family *family,
138 struct genl_multicast_group *grp)
139{
140 int id;
141 unsigned long *new_groups;
142 int err = 0;
143
144 BUG_ON(grp->name[0] == '\0');
145
146 genl_lock();
147
148 /* special-case our own group */
149 if (grp == ¬ify_grp)
150 id = GENL_ID_CTRL;
151 else
152 id = find_first_zero_bit(mc_groups,
153 mc_groups_longs * BITS_PER_LONG);
154
155
156 if (id >= mc_groups_longs * BITS_PER_LONG) {
157 size_t nlen = (mc_groups_longs + 1) * sizeof(unsigned long);
158
159 if (mc_groups == &mc_group_start) {
160 new_groups = kzalloc(nlen, GFP_KERNEL);
161 if (!new_groups) {
162 err = -ENOMEM;
163 goto out;
164 }
165 mc_groups = new_groups;
166 *mc_groups = mc_group_start;
167 } else {
168 new_groups = krealloc(mc_groups, nlen, GFP_KERNEL);
169 if (!new_groups) {
170 err = -ENOMEM;
171 goto out;
172 }
173 mc_groups = new_groups;
174 mc_groups[mc_groups_longs] = 0;
175 }
176 mc_groups_longs++;
177 }
178
179 if (family->netnsok) {
180 struct net *net;
181
182 netlink_table_grab();
183 rcu_read_lock();
184 for_each_net_rcu(net) {
185 err = __netlink_change_ngroups(net->genl_sock,
186 mc_groups_longs * BITS_PER_LONG);
187 if (err) {
188 /*
189 * No need to roll back, can only fail if
190 * memory allocation fails and then the
191 * number of _possible_ groups has been
192 * increased on some sockets which is ok.
193 */
194 rcu_read_unlock();
195 netlink_table_ungrab();
196 goto out;
197 }
198 }
199 rcu_read_unlock();
200 netlink_table_ungrab();
201 } else {
202 err = netlink_change_ngroups(init_net.genl_sock,
203 mc_groups_longs * BITS_PER_LONG);
204 if (err)
205 goto out;
206 }
207
208 grp->id = id;
209 set_bit(id, mc_groups);
210 list_add_tail(&grp->list, &family->mcast_groups);
211 grp->family = family;
212
213 genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, grp);
214 out:
215 genl_unlock();
216 return err;
217}
218EXPORT_SYMBOL(genl_register_mc_group);
219
220static void __genl_unregister_mc_group(struct genl_family *family,
221 struct genl_multicast_group *grp)
222{
223 struct net *net;
224 BUG_ON(grp->family != family);
225
226 netlink_table_grab();
227 rcu_read_lock();
228 for_each_net_rcu(net)
229 __netlink_clear_multicast_users(net->genl_sock, grp->id);
230 rcu_read_unlock();
231 netlink_table_ungrab();
232
233 clear_bit(grp->id, mc_groups);
234 list_del(&grp->list);
235 genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, grp);
236 grp->id = 0;
237 grp->family = NULL;
238}
239
240/**
241 * genl_unregister_mc_group - unregister a multicast group
242 *
243 * Unregisters the specified multicast group and notifies userspace
244 * about it. All current listeners on the group are removed.
245 *
246 * Note: It is not necessary to unregister all multicast groups before
247 * unregistering the family, unregistering the family will cause
248 * all assigned multicast groups to be unregistered automatically.
249 *
250 * @family: Generic netlink family the group belongs to.
251 * @grp: The group to unregister, must have been registered successfully
252 * previously.
253 */
254void genl_unregister_mc_group(struct genl_family *family,
255 struct genl_multicast_group *grp)
256{
257 genl_lock();
258 __genl_unregister_mc_group(family, grp);
259 genl_unlock();
260}
261EXPORT_SYMBOL(genl_unregister_mc_group);
262
263static void genl_unregister_mc_groups(struct genl_family *family)
264{
265 struct genl_multicast_group *grp, *tmp;
266
267 list_for_each_entry_safe(grp, tmp, &family->mcast_groups, list)
268 __genl_unregister_mc_group(family, grp);
269}
270
271/**
272 * genl_register_ops - register generic netlink operations
273 * @family: generic netlink family
274 * @ops: operations to be registered
275 *
276 * Registers the specified operations and assigns them to the specified
277 * family. Either a doit or dumpit callback must be specified or the
278 * operation will fail. Only one operation structure per command
279 * identifier may be registered.
280 *
281 * See include/net/genetlink.h for more documenation on the operations
282 * structure.
283 *
284 * Returns 0 on success or a negative error code.
285 */
286int genl_register_ops(struct genl_family *family, struct genl_ops *ops)
287{
288 int err = -EINVAL;
289
290 if (ops->dumpit == NULL && ops->doit == NULL)
291 goto errout;
292
293 if (genl_get_cmd(ops->cmd, family)) {
294 err = -EEXIST;
295 goto errout;
296 }
297
298 if (ops->dumpit)
299 ops->flags |= GENL_CMD_CAP_DUMP;
300 if (ops->doit)
301 ops->flags |= GENL_CMD_CAP_DO;
302 if (ops->policy)
303 ops->flags |= GENL_CMD_CAP_HASPOL;
304
305 genl_lock();
306 list_add_tail(&ops->ops_list, &family->ops_list);
307 genl_unlock();
308
309 genl_ctrl_event(CTRL_CMD_NEWOPS, ops);
310 err = 0;
311errout:
312 return err;
313}
314EXPORT_SYMBOL(genl_register_ops);
315
316/**
317 * genl_unregister_ops - unregister generic netlink operations
318 * @family: generic netlink family
319 * @ops: operations to be unregistered
320 *
321 * Unregisters the specified operations and unassigns them from the
322 * specified family. The operation blocks until the current message
323 * processing has finished and doesn't start again until the
324 * unregister process has finished.
325 *
326 * Note: It is not necessary to unregister all operations before
327 * unregistering the family, unregistering the family will cause
328 * all assigned operations to be unregistered automatically.
329 *
330 * Returns 0 on success or a negative error code.
331 */
332int genl_unregister_ops(struct genl_family *family, struct genl_ops *ops)
333{
334 struct genl_ops *rc;
335
336 genl_lock();
337 list_for_each_entry(rc, &family->ops_list, ops_list) {
338 if (rc == ops) {
339 list_del(&ops->ops_list);
340 genl_unlock();
341 genl_ctrl_event(CTRL_CMD_DELOPS, ops);
342 return 0;
343 }
344 }
345 genl_unlock();
346
347 return -ENOENT;
348}
349EXPORT_SYMBOL(genl_unregister_ops);
350
351/**
352 * genl_register_family - register a generic netlink family
353 * @family: generic netlink family
354 *
355 * Registers the specified family after validating it first. Only one
356 * family may be registered with the same family name or identifier.
357 * The family id may equal GENL_ID_GENERATE causing an unique id to
358 * be automatically generated and assigned.
359 *
360 * Return 0 on success or a negative error code.
361 */
362int genl_register_family(struct genl_family *family)
363{
364 int err = -EINVAL;
365
366 if (family->id && family->id < GENL_MIN_ID)
367 goto errout;
368
369 if (family->id > GENL_MAX_ID)
370 goto errout;
371
372 INIT_LIST_HEAD(&family->ops_list);
373 INIT_LIST_HEAD(&family->mcast_groups);
374
375 genl_lock();
376
377 if (genl_family_find_byname(family->name)) {
378 err = -EEXIST;
379 goto errout_locked;
380 }
381
382 if (family->id == GENL_ID_GENERATE) {
383 u16 newid = genl_generate_id();
384
385 if (!newid) {
386 err = -ENOMEM;
387 goto errout_locked;
388 }
389
390 family->id = newid;
391 } else if (genl_family_find_byid(family->id)) {
392 err = -EEXIST;
393 goto errout_locked;
394 }
395
396 if (family->maxattr) {
397 family->attrbuf = kmalloc((family->maxattr+1) *
398 sizeof(struct nlattr *), GFP_KERNEL);
399 if (family->attrbuf == NULL) {
400 err = -ENOMEM;
401 goto errout_locked;
402 }
403 } else
404 family->attrbuf = NULL;
405
406 list_add_tail(&family->family_list, genl_family_chain(family->id));
407 genl_unlock();
408
409 genl_ctrl_event(CTRL_CMD_NEWFAMILY, family);
410
411 return 0;
412
413errout_locked:
414 genl_unlock();
415errout:
416 return err;
417}
418EXPORT_SYMBOL(genl_register_family);
419
420/**
421 * genl_register_family_with_ops - register a generic netlink family
422 * @family: generic netlink family
423 * @ops: operations to be registered
424 * @n_ops: number of elements to register
425 *
426 * Registers the specified family and operations from the specified table.
427 * Only one family may be registered with the same family name or identifier.
428 *
429 * The family id may equal GENL_ID_GENERATE causing an unique id to
430 * be automatically generated and assigned.
431 *
432 * Either a doit or dumpit callback must be specified for every registered
433 * operation or the function will fail. Only one operation structure per
434 * command identifier may be registered.
435 *
436 * See include/net/genetlink.h for more documenation on the operations
437 * structure.
438 *
439 * This is equivalent to calling genl_register_family() followed by
440 * genl_register_ops() for every operation entry in the table taking
441 * care to unregister the family on error path.
442 *
443 * Return 0 on success or a negative error code.
444 */
445int genl_register_family_with_ops(struct genl_family *family,
446 struct genl_ops *ops, size_t n_ops)
447{
448 int err, i;
449
450 err = genl_register_family(family);
451 if (err)
452 return err;
453
454 for (i = 0; i < n_ops; ++i, ++ops) {
455 err = genl_register_ops(family, ops);
456 if (err)
457 goto err_out;
458 }
459 return 0;
460err_out:
461 genl_unregister_family(family);
462 return err;
463}
464EXPORT_SYMBOL(genl_register_family_with_ops);
465
466/**
467 * genl_unregister_family - unregister generic netlink family
468 * @family: generic netlink family
469 *
470 * Unregisters the specified family.
471 *
472 * Returns 0 on success or a negative error code.
473 */
474int genl_unregister_family(struct genl_family *family)
475{
476 struct genl_family *rc;
477
478 genl_lock();
479
480 genl_unregister_mc_groups(family);
481
482 list_for_each_entry(rc, genl_family_chain(family->id), family_list) {
483 if (family->id != rc->id || strcmp(rc->name, family->name))
484 continue;
485
486 list_del(&rc->family_list);
487 INIT_LIST_HEAD(&family->ops_list);
488 genl_unlock();
489
490 kfree(family->attrbuf);
491 genl_ctrl_event(CTRL_CMD_DELFAMILY, family);
492 return 0;
493 }
494
495 genl_unlock();
496
497 return -ENOENT;
498}
499EXPORT_SYMBOL(genl_unregister_family);
500
501/**
502 * genlmsg_put - Add generic netlink header to netlink message
503 * @skb: socket buffer holding the message
504 * @pid: netlink pid the message is addressed to
505 * @seq: sequence number (usually the one of the sender)
506 * @family: generic netlink family
507 * @flags netlink message flags
508 * @cmd: generic netlink command
509 *
510 * Returns pointer to user specific header
511 */
512void *genlmsg_put(struct sk_buff *skb, u32 pid, u32 seq,
513 struct genl_family *family, int flags, u8 cmd)
514{
515 struct nlmsghdr *nlh;
516 struct genlmsghdr *hdr;
517
518 nlh = nlmsg_put(skb, pid, seq, family->id, GENL_HDRLEN +
519 family->hdrsize, flags);
520 if (nlh == NULL)
521 return NULL;
522
523 hdr = nlmsg_data(nlh);
524 hdr->cmd = cmd;
525 hdr->version = family->version;
526 hdr->reserved = 0;
527
528 return (char *) hdr + GENL_HDRLEN;
529}
530EXPORT_SYMBOL(genlmsg_put);
531
532static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
533{
534 struct genl_ops *ops;
535 struct genl_family *family;
536 struct net *net = sock_net(skb->sk);
537 struct genl_info info;
538 struct genlmsghdr *hdr = nlmsg_data(nlh);
539 int hdrlen, err;
540
541 family = genl_family_find_byid(nlh->nlmsg_type);
542 if (family == NULL)
543 return -ENOENT;
544
545 /* this family doesn't exist in this netns */
546 if (!family->netnsok && !net_eq(net, &init_net))
547 return -ENOENT;
548
549 hdrlen = GENL_HDRLEN + family->hdrsize;
550 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
551 return -EINVAL;
552
553 ops = genl_get_cmd(hdr->cmd, family);
554 if (ops == NULL)
555 return -EOPNOTSUPP;
556
557 if ((ops->flags & GENL_ADMIN_PERM) &&
558 !capable(CAP_NET_ADMIN))
559 return -EPERM;
560
561 if (nlh->nlmsg_flags & NLM_F_DUMP) {
562 if (ops->dumpit == NULL)
563 return -EOPNOTSUPP;
564
565 genl_unlock();
566 {
567 struct netlink_dump_control c = {
568 .dump = ops->dumpit,
569 .done = ops->done,
570 };
571 err = netlink_dump_start(net->genl_sock, skb, nlh, &c);
572 }
573 genl_lock();
574 return err;
575 }
576
577 if (ops->doit == NULL)
578 return -EOPNOTSUPP;
579
580 if (family->attrbuf) {
581 err = nlmsg_parse(nlh, hdrlen, family->attrbuf, family->maxattr,
582 ops->policy);
583 if (err < 0)
584 return err;
585 }
586
587 info.snd_seq = nlh->nlmsg_seq;
588 info.snd_pid = NETLINK_CB(skb).pid;
589 info.nlhdr = nlh;
590 info.genlhdr = nlmsg_data(nlh);
591 info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
592 info.attrs = family->attrbuf;
593 genl_info_net_set(&info, net);
594 memset(&info.user_ptr, 0, sizeof(info.user_ptr));
595
596 if (family->pre_doit) {
597 err = family->pre_doit(ops, skb, &info);
598 if (err)
599 return err;
600 }
601
602 err = ops->doit(skb, &info);
603
604 if (family->post_doit)
605 family->post_doit(ops, skb, &info);
606
607 return err;
608}
609
610static void genl_rcv(struct sk_buff *skb)
611{
612 genl_lock();
613 netlink_rcv_skb(skb, &genl_rcv_msg);
614 genl_unlock();
615}
616
617/**************************************************************************
618 * Controller
619 **************************************************************************/
620
621static struct genl_family genl_ctrl = {
622 .id = GENL_ID_CTRL,
623 .name = "nlctrl",
624 .version = 0x2,
625 .maxattr = CTRL_ATTR_MAX,
626 .netnsok = true,
627};
628
629static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
630 u32 flags, struct sk_buff *skb, u8 cmd)
631{
632 void *hdr;
633
634 hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
635 if (hdr == NULL)
636 return -1;
637
638 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
639 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) ||
640 nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) ||
641 nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) ||
642 nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr))
643 goto nla_put_failure;
644
645 if (!list_empty(&family->ops_list)) {
646 struct nlattr *nla_ops;
647 struct genl_ops *ops;
648 int idx = 1;
649
650 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
651 if (nla_ops == NULL)
652 goto nla_put_failure;
653
654 list_for_each_entry(ops, &family->ops_list, ops_list) {
655 struct nlattr *nest;
656
657 nest = nla_nest_start(skb, idx++);
658 if (nest == NULL)
659 goto nla_put_failure;
660
661 if (nla_put_u32(skb, CTRL_ATTR_OP_ID, ops->cmd) ||
662 nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, ops->flags))
663 goto nla_put_failure;
664
665 nla_nest_end(skb, nest);
666 }
667
668 nla_nest_end(skb, nla_ops);
669 }
670
671 if (!list_empty(&family->mcast_groups)) {
672 struct genl_multicast_group *grp;
673 struct nlattr *nla_grps;
674 int idx = 1;
675
676 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
677 if (nla_grps == NULL)
678 goto nla_put_failure;
679
680 list_for_each_entry(grp, &family->mcast_groups, list) {
681 struct nlattr *nest;
682
683 nest = nla_nest_start(skb, idx++);
684 if (nest == NULL)
685 goto nla_put_failure;
686
687 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id) ||
688 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
689 grp->name))
690 goto nla_put_failure;
691
692 nla_nest_end(skb, nest);
693 }
694 nla_nest_end(skb, nla_grps);
695 }
696
697 return genlmsg_end(skb, hdr);
698
699nla_put_failure:
700 genlmsg_cancel(skb, hdr);
701 return -EMSGSIZE;
702}
703
704static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 pid,
705 u32 seq, u32 flags, struct sk_buff *skb,
706 u8 cmd)
707{
708 void *hdr;
709 struct nlattr *nla_grps;
710 struct nlattr *nest;
711
712 hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
713 if (hdr == NULL)
714 return -1;
715
716 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, grp->family->name) ||
717 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, grp->family->id))
718 goto nla_put_failure;
719
720 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
721 if (nla_grps == NULL)
722 goto nla_put_failure;
723
724 nest = nla_nest_start(skb, 1);
725 if (nest == NULL)
726 goto nla_put_failure;
727
728 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id) ||
729 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
730 grp->name))
731 goto nla_put_failure;
732
733 nla_nest_end(skb, nest);
734 nla_nest_end(skb, nla_grps);
735
736 return genlmsg_end(skb, hdr);
737
738nla_put_failure:
739 genlmsg_cancel(skb, hdr);
740 return -EMSGSIZE;
741}
742
743static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
744{
745
746 int i, n = 0;
747 struct genl_family *rt;
748 struct net *net = sock_net(skb->sk);
749 int chains_to_skip = cb->args[0];
750 int fams_to_skip = cb->args[1];
751
752 for (i = chains_to_skip; i < GENL_FAM_TAB_SIZE; i++) {
753 n = 0;
754 list_for_each_entry(rt, genl_family_chain(i), family_list) {
755 if (!rt->netnsok && !net_eq(net, &init_net))
756 continue;
757 if (++n < fams_to_skip)
758 continue;
759 if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).pid,
760 cb->nlh->nlmsg_seq, NLM_F_MULTI,
761 skb, CTRL_CMD_NEWFAMILY) < 0)
762 goto errout;
763 }
764
765 fams_to_skip = 0;
766 }
767
768errout:
769 cb->args[0] = i;
770 cb->args[1] = n;
771
772 return skb->len;
773}
774
775static struct sk_buff *ctrl_build_family_msg(struct genl_family *family,
776 u32 pid, int seq, u8 cmd)
777{
778 struct sk_buff *skb;
779 int err;
780
781 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
782 if (skb == NULL)
783 return ERR_PTR(-ENOBUFS);
784
785 err = ctrl_fill_info(family, pid, seq, 0, skb, cmd);
786 if (err < 0) {
787 nlmsg_free(skb);
788 return ERR_PTR(err);
789 }
790
791 return skb;
792}
793
794static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_multicast_group *grp,
795 u32 pid, int seq, u8 cmd)
796{
797 struct sk_buff *skb;
798 int err;
799
800 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
801 if (skb == NULL)
802 return ERR_PTR(-ENOBUFS);
803
804 err = ctrl_fill_mcgrp_info(grp, pid, seq, 0, skb, cmd);
805 if (err < 0) {
806 nlmsg_free(skb);
807 return ERR_PTR(err);
808 }
809
810 return skb;
811}
812
813static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
814 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 },
815 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
816 .len = GENL_NAMSIZ - 1 },
817};
818
819static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
820{
821 struct sk_buff *msg;
822 struct genl_family *res = NULL;
823 int err = -EINVAL;
824
825 if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
826 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
827 res = genl_family_find_byid(id);
828 err = -ENOENT;
829 }
830
831 if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
832 char *name;
833
834 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
835 res = genl_family_find_byname(name);
836#ifdef CONFIG_MODULES
837 if (res == NULL) {
838 genl_unlock();
839 request_module("net-pf-%d-proto-%d-family-%s",
840 PF_NETLINK, NETLINK_GENERIC, name);
841 genl_lock();
842 res = genl_family_find_byname(name);
843 }
844#endif
845 err = -ENOENT;
846 }
847
848 if (res == NULL)
849 return err;
850
851 if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) {
852 /* family doesn't exist here */
853 return -ENOENT;
854 }
855
856 msg = ctrl_build_family_msg(res, info->snd_pid, info->snd_seq,
857 CTRL_CMD_NEWFAMILY);
858 if (IS_ERR(msg))
859 return PTR_ERR(msg);
860
861 return genlmsg_reply(msg, info);
862}
863
864static int genl_ctrl_event(int event, void *data)
865{
866 struct sk_buff *msg;
867 struct genl_family *family;
868 struct genl_multicast_group *grp;
869
870 /* genl is still initialising */
871 if (!init_net.genl_sock)
872 return 0;
873
874 switch (event) {
875 case CTRL_CMD_NEWFAMILY:
876 case CTRL_CMD_DELFAMILY:
877 family = data;
878 msg = ctrl_build_family_msg(family, 0, 0, event);
879 break;
880 case CTRL_CMD_NEWMCAST_GRP:
881 case CTRL_CMD_DELMCAST_GRP:
882 grp = data;
883 family = grp->family;
884 msg = ctrl_build_mcgrp_msg(data, 0, 0, event);
885 break;
886 default:
887 return -EINVAL;
888 }
889
890 if (IS_ERR(msg))
891 return PTR_ERR(msg);
892
893 if (!family->netnsok) {
894 genlmsg_multicast_netns(&init_net, msg, 0,
895 GENL_ID_CTRL, GFP_KERNEL);
896 } else {
897 rcu_read_lock();
898 genlmsg_multicast_allns(msg, 0, GENL_ID_CTRL, GFP_ATOMIC);
899 rcu_read_unlock();
900 }
901
902 return 0;
903}
904
905static struct genl_ops genl_ctrl_ops = {
906 .cmd = CTRL_CMD_GETFAMILY,
907 .doit = ctrl_getfamily,
908 .dumpit = ctrl_dumpfamily,
909 .policy = ctrl_policy,
910};
911
912static struct genl_multicast_group notify_grp = {
913 .name = "notify",
914};
915
916static int __net_init genl_pernet_init(struct net *net)
917{
918 /* we'll bump the group number right afterwards */
919 net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, 0,
920 genl_rcv, &genl_mutex,
921 THIS_MODULE);
922
923 if (!net->genl_sock && net_eq(net, &init_net))
924 panic("GENL: Cannot initialize generic netlink\n");
925
926 if (!net->genl_sock)
927 return -ENOMEM;
928
929 return 0;
930}
931
932static void __net_exit genl_pernet_exit(struct net *net)
933{
934 netlink_kernel_release(net->genl_sock);
935 net->genl_sock = NULL;
936}
937
938static struct pernet_operations genl_pernet_ops = {
939 .init = genl_pernet_init,
940 .exit = genl_pernet_exit,
941};
942
943static int __init genl_init(void)
944{
945 int i, err;
946
947 for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
948 INIT_LIST_HEAD(&family_ht[i]);
949
950 err = genl_register_family_with_ops(&genl_ctrl, &genl_ctrl_ops, 1);
951 if (err < 0)
952 goto problem;
953
954 netlink_set_nonroot(NETLINK_GENERIC, NL_NONROOT_RECV);
955
956 err = register_pernet_subsys(&genl_pernet_ops);
957 if (err)
958 goto problem;
959
960 err = genl_register_mc_group(&genl_ctrl, ¬ify_grp);
961 if (err < 0)
962 goto problem;
963
964 return 0;
965
966problem:
967 panic("GENL: Cannot register controller: %d\n", err);
968}
969
970subsys_initcall(genl_init);
971
972static int genlmsg_mcast(struct sk_buff *skb, u32 pid, unsigned long group,
973 gfp_t flags)
974{
975 struct sk_buff *tmp;
976 struct net *net, *prev = NULL;
977 int err;
978
979 for_each_net_rcu(net) {
980 if (prev) {
981 tmp = skb_clone(skb, flags);
982 if (!tmp) {
983 err = -ENOMEM;
984 goto error;
985 }
986 err = nlmsg_multicast(prev->genl_sock, tmp,
987 pid, group, flags);
988 if (err)
989 goto error;
990 }
991
992 prev = net;
993 }
994
995 return nlmsg_multicast(prev->genl_sock, skb, pid, group, flags);
996 error:
997 kfree_skb(skb);
998 return err;
999}
1000
1001int genlmsg_multicast_allns(struct sk_buff *skb, u32 pid, unsigned int group,
1002 gfp_t flags)
1003{
1004 return genlmsg_mcast(skb, pid, group, flags);
1005}
1006EXPORT_SYMBOL(genlmsg_multicast_allns);
1007
1008void genl_notify(struct sk_buff *skb, struct net *net, u32 pid, u32 group,
1009 struct nlmsghdr *nlh, gfp_t flags)
1010{
1011 struct sock *sk = net->genl_sock;
1012 int report = 0;
1013
1014 if (nlh)
1015 report = nlmsg_report(nlh);
1016
1017 nlmsg_notify(sk, skb, pid, group, report, flags);
1018}
1019EXPORT_SYMBOL(genl_notify);