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geneve: change NET_UDP_TUNNEL dependency to select
[linux/fpc-iii.git] / net / netlink / genetlink.c
blob25eeb6d2a75a69059f387be103345e844284f743
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
25 static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */
26 static DECLARE_RWSEM(cb_lock);
27
28 atomic_t genl_sk_destructing_cnt = ATOMIC_INIT(0);
29 DECLARE_WAIT_QUEUE_HEAD(genl_sk_destructing_waitq);
30
31 void genl_lock(void)
32 {
33 mutex_lock(&genl_mutex);
34 }
35 EXPORT_SYMBOL(genl_lock);
36
37 void genl_unlock(void)
38 {
39 mutex_unlock(&genl_mutex);
40 }
41 EXPORT_SYMBOL(genl_unlock);
42
43 #ifdef CONFIG_LOCKDEP
44 bool lockdep_genl_is_held(void)
45 {
46 return lockdep_is_held(&genl_mutex);
47 }
48 EXPORT_SYMBOL(lockdep_genl_is_held);
49 #endif
50
51 static void genl_lock_all(void)
52 {
53 down_write(&cb_lock);
54 genl_lock();
55 }
56
57 static void genl_unlock_all(void)
58 {
59 genl_unlock();
60 up_write(&cb_lock);
61 }
62
63 static 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 */
83 static unsigned long mc_group_start = 0x3 | BIT(GENL_ID_CTRL) |
84 BIT(GENL_ID_VFS_DQUOT) |
85 BIT(GENL_ID_PMCRAID);
86 static unsigned long *mc_groups = &mc_group_start;
87 static unsigned long mc_groups_longs = 1;
88
89 static int genl_ctrl_event(int event, const struct genl_family *family,
90 const struct genl_multicast_group *grp,
91 int grp_id);
92
93 static const struct genl_family *genl_family_find_byid(unsigned int id)
94 {
95 return idr_find(&genl_fam_idr, id);
96 }
97
98 static 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
110 static 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
122 static 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
182 static struct genl_family genl_ctrl;
183
184 static 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
262 static 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
287 static 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 */
322 int 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(&genl_fam_idr, family,
366 start, end + 1, GFP_KERNEL);
367 if (family->id < 0) {
368 err = family->id;
369 goto errout_locked;
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
386 errout_remove:
387 idr_remove(&genl_fam_idr, family->id);
388 kfree(family->attrbuf);
389 errout_locked:
390 genl_unlock_all();
391 return err;
392 }
393 EXPORT_SYMBOL(genl_register_family);
394
395 /**
396 * genl_unregister_family - unregister generic netlink family
397 * @family: generic netlink family
398 *
399 * Unregisters the specified family.
400 *
401 * Returns 0 on success or a negative error code.
402 */
403 int genl_unregister_family(const struct genl_family *family)
404 {
405 genl_lock_all();
406
407 if (!genl_family_find_byid(family->id)) {
408 genl_unlock_all();
409 return -ENOENT;
410 }
411
412 genl_unregister_mc_groups(family);
413
414 idr_remove(&genl_fam_idr, family->id);
415
416 up_write(&cb_lock);
417 wait_event(genl_sk_destructing_waitq,
418 atomic_read(&genl_sk_destructing_cnt) == 0);
419 genl_unlock();
420
421 kfree(family->attrbuf);
422
423 genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 0);
424
425 return 0;
426 }
427 EXPORT_SYMBOL(genl_unregister_family);
428
429 /**
430 * genlmsg_put - Add generic netlink header to netlink message
431 * @skb: socket buffer holding the message
432 * @portid: netlink portid the message is addressed to
433 * @seq: sequence number (usually the one of the sender)
434 * @family: generic netlink family
435 * @flags: netlink message flags
436 * @cmd: generic netlink command
437 *
438 * Returns pointer to user specific header
439 */
440 void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
441 const struct genl_family *family, int flags, u8 cmd)
442 {
443 struct nlmsghdr *nlh;
444 struct genlmsghdr *hdr;
445
446 nlh = nlmsg_put(skb, portid, seq, family->id, GENL_HDRLEN +
447 family->hdrsize, flags);
448 if (nlh == NULL)
449 return NULL;
450
451 hdr = nlmsg_data(nlh);
452 hdr->cmd = cmd;
453 hdr->version = family->version;
454 hdr->reserved = 0;
455
456 return (char *) hdr + GENL_HDRLEN;
457 }
458 EXPORT_SYMBOL(genlmsg_put);
459
460 static int genl_lock_start(struct netlink_callback *cb)
461 {
462 /* our ops are always const - netlink API doesn't propagate that */
463 const struct genl_ops *ops = cb->data;
464 int rc = 0;
465
466 if (ops->start) {
467 genl_lock();
468 rc = ops->start(cb);
469 genl_unlock();
470 }
471 return rc;
472 }
473
474 static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
475 {
476 /* our ops are always const - netlink API doesn't propagate that */
477 const struct genl_ops *ops = cb->data;
478 int rc;
479
480 genl_lock();
481 rc = ops->dumpit(skb, cb);
482 genl_unlock();
483 return rc;
484 }
485
486 static int genl_lock_done(struct netlink_callback *cb)
487 {
488 /* our ops are always const - netlink API doesn't propagate that */
489 const struct genl_ops *ops = cb->data;
490 int rc = 0;
491
492 if (ops->done) {
493 genl_lock();
494 rc = ops->done(cb);
495 genl_unlock();
496 }
497 return rc;
498 }
499
500 static int genl_family_rcv_msg(const struct genl_family *family,
501 struct sk_buff *skb,
502 struct nlmsghdr *nlh,
503 struct netlink_ext_ack *extack)
504 {
505 const struct genl_ops *ops;
506 struct net *net = sock_net(skb->sk);
507 struct genl_info info;
508 struct genlmsghdr *hdr = nlmsg_data(nlh);
509 struct nlattr **attrbuf;
510 int hdrlen, err;
511
512 /* this family doesn't exist in this netns */
513 if (!family->netnsok && !net_eq(net, &init_net))
514 return -ENOENT;
515
516 hdrlen = GENL_HDRLEN + family->hdrsize;
517 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
518 return -EINVAL;
519
520 ops = genl_get_cmd(hdr->cmd, family);
521 if (ops == NULL)
522 return -EOPNOTSUPP;
523
524 if ((ops->flags & GENL_ADMIN_PERM) &&
525 !netlink_capable(skb, CAP_NET_ADMIN))
526 return -EPERM;
527
528 if ((ops->flags & GENL_UNS_ADMIN_PERM) &&
529 !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
530 return -EPERM;
531
532 if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP) {
533 int rc;
534
535 if (ops->dumpit == NULL)
536 return -EOPNOTSUPP;
537
538 if (!family->parallel_ops) {
539 struct netlink_dump_control c = {
540 .module = family->module,
541 /* we have const, but the netlink API doesn't */
542 .data = (void *)ops,
543 .start = genl_lock_start,
544 .dump = genl_lock_dumpit,
545 .done = genl_lock_done,
546 };
547
548 genl_unlock();
549 rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
550 genl_lock();
551
552 } else {
553 struct netlink_dump_control c = {
554 .module = family->module,
555 .start = ops->start,
556 .dump = ops->dumpit,
557 .done = ops->done,
558 };
559
560 rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
561 }
562
563 return rc;
564 }
565
566 if (ops->doit == NULL)
567 return -EOPNOTSUPP;
568
569 if (family->maxattr && family->parallel_ops) {
570 attrbuf = kmalloc_array(family->maxattr + 1,
571 sizeof(struct nlattr *),
572 GFP_KERNEL);
573 if (attrbuf == NULL)
574 return -ENOMEM;
575 } else
576 attrbuf = family->attrbuf;
577
578 if (attrbuf) {
579 err = nlmsg_parse(nlh, hdrlen, attrbuf, family->maxattr,
580 ops->policy, extack);
581 if (err < 0)
582 goto out;
583 }
584
585 info.snd_seq = nlh->nlmsg_seq;
586 info.snd_portid = NETLINK_CB(skb).portid;
587 info.nlhdr = nlh;
588 info.genlhdr = nlmsg_data(nlh);
589 info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
590 info.attrs = attrbuf;
591 info.extack = extack;
592 genl_info_net_set(&info, net);
593 memset(&info.user_ptr, 0, sizeof(info.user_ptr));
594
595 if (family->pre_doit) {
596 err = family->pre_doit(ops, skb, &info);
597 if (err)
598 goto out;
599 }
600
601 err = ops->doit(skb, &info);
602
603 if (family->post_doit)
604 family->post_doit(ops, skb, &info);
605
606 out:
607 if (family->parallel_ops)
608 kfree(attrbuf);
609
610 return err;
611 }
612
613 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
614 struct netlink_ext_ack *extack)
615 {
616 const struct genl_family *family;
617 int err;
618
619 family = genl_family_find_byid(nlh->nlmsg_type);
620 if (family == NULL)
621 return -ENOENT;
622
623 if (!family->parallel_ops)
624 genl_lock();
625
626 err = genl_family_rcv_msg(family, skb, nlh, extack);
627
628 if (!family->parallel_ops)
629 genl_unlock();
630
631 return err;
632 }
633
634 static void genl_rcv(struct sk_buff *skb)
635 {
636 down_read(&cb_lock);
637 netlink_rcv_skb(skb, &genl_rcv_msg);
638 up_read(&cb_lock);
639 }
640
641 /**************************************************************************
642 * Controller
643 **************************************************************************/
644
645 static struct genl_family genl_ctrl;
646
647 static int ctrl_fill_info(const struct genl_family *family, u32 portid, u32 seq,
648 u32 flags, struct sk_buff *skb, u8 cmd)
649 {
650 void *hdr;
651
652 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
653 if (hdr == NULL)
654 return -1;
655
656 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
657 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) ||
658 nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) ||
659 nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) ||
660 nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr))
661 goto nla_put_failure;
662
663 if (family->n_ops) {
664 struct nlattr *nla_ops;
665 int i;
666
667 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
668 if (nla_ops == NULL)
669 goto nla_put_failure;
670
671 for (i = 0; i < family->n_ops; i++) {
672 struct nlattr *nest;
673 const struct genl_ops *ops = &family->ops[i];
674 u32 op_flags = ops->flags;
675
676 if (ops->dumpit)
677 op_flags |= GENL_CMD_CAP_DUMP;
678 if (ops->doit)
679 op_flags |= GENL_CMD_CAP_DO;
680 if (ops->policy)
681 op_flags |= GENL_CMD_CAP_HASPOL;
682
683 nest = nla_nest_start(skb, i + 1);
684 if (nest == NULL)
685 goto nla_put_failure;
686
687 if (nla_put_u32(skb, CTRL_ATTR_OP_ID, ops->cmd) ||
688 nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, op_flags))
689 goto nla_put_failure;
690
691 nla_nest_end(skb, nest);
692 }
693
694 nla_nest_end(skb, nla_ops);
695 }
696
697 if (family->n_mcgrps) {
698 struct nlattr *nla_grps;
699 int i;
700
701 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
702 if (nla_grps == NULL)
703 goto nla_put_failure;
704
705 for (i = 0; i < family->n_mcgrps; i++) {
706 struct nlattr *nest;
707 const struct genl_multicast_group *grp;
708
709 grp = &family->mcgrps[i];
710
711 nest = nla_nest_start(skb, i + 1);
712 if (nest == NULL)
713 goto nla_put_failure;
714
715 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID,
716 family->mcgrp_offset + i) ||
717 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
718 grp->name))
719 goto nla_put_failure;
720
721 nla_nest_end(skb, nest);
722 }
723 nla_nest_end(skb, nla_grps);
724 }
725
726 genlmsg_end(skb, hdr);
727 return 0;
728
729 nla_put_failure:
730 genlmsg_cancel(skb, hdr);
731 return -EMSGSIZE;
732 }
733
734 static int ctrl_fill_mcgrp_info(const struct genl_family *family,
735 const struct genl_multicast_group *grp,
736 int grp_id, u32 portid, u32 seq, u32 flags,
737 struct sk_buff *skb, u8 cmd)
738 {
739 void *hdr;
740 struct nlattr *nla_grps;
741 struct nlattr *nest;
742
743 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
744 if (hdr == NULL)
745 return -1;
746
747 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
748 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id))
749 goto nla_put_failure;
750
751 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
752 if (nla_grps == NULL)
753 goto nla_put_failure;
754
755 nest = nla_nest_start(skb, 1);
756 if (nest == NULL)
757 goto nla_put_failure;
758
759 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp_id) ||
760 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
761 grp->name))
762 goto nla_put_failure;
763
764 nla_nest_end(skb, nest);
765 nla_nest_end(skb, nla_grps);
766
767 genlmsg_end(skb, hdr);
768 return 0;
769
770 nla_put_failure:
771 genlmsg_cancel(skb, hdr);
772 return -EMSGSIZE;
773 }
774
775 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
776 {
777 int n = 0;
778 struct genl_family *rt;
779 struct net *net = sock_net(skb->sk);
780 int fams_to_skip = cb->args[0];
781 unsigned int id;
782
783 idr_for_each_entry(&genl_fam_idr, rt, id) {
784 if (!rt->netnsok && !net_eq(net, &init_net))
785 continue;
786
787 if (n++ < fams_to_skip)
788 continue;
789
790 if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid,
791 cb->nlh->nlmsg_seq, NLM_F_MULTI,
792 skb, CTRL_CMD_NEWFAMILY) < 0) {
793 n--;
794 break;
795 }
796 }
797
798 cb->args[0] = n;
799 return skb->len;
800 }
801
802 static struct sk_buff *ctrl_build_family_msg(const struct genl_family *family,
803 u32 portid, int seq, u8 cmd)
804 {
805 struct sk_buff *skb;
806 int err;
807
808 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
809 if (skb == NULL)
810 return ERR_PTR(-ENOBUFS);
811
812 err = ctrl_fill_info(family, portid, seq, 0, skb, cmd);
813 if (err < 0) {
814 nlmsg_free(skb);
815 return ERR_PTR(err);
816 }
817
818 return skb;
819 }
820
821 static struct sk_buff *
822 ctrl_build_mcgrp_msg(const struct genl_family *family,
823 const struct genl_multicast_group *grp,
824 int grp_id, u32 portid, int seq, u8 cmd)
825 {
826 struct sk_buff *skb;
827 int err;
828
829 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
830 if (skb == NULL)
831 return ERR_PTR(-ENOBUFS);
832
833 err = ctrl_fill_mcgrp_info(family, grp, grp_id, portid,
834 seq, 0, skb, cmd);
835 if (err < 0) {
836 nlmsg_free(skb);
837 return ERR_PTR(err);
838 }
839
840 return skb;
841 }
842
843 static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
844 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 },
845 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
846 .len = GENL_NAMSIZ - 1 },
847 };
848
849 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
850 {
851 struct sk_buff *msg;
852 const struct genl_family *res = NULL;
853 int err = -EINVAL;
854
855 if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
856 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
857 res = genl_family_find_byid(id);
858 err = -ENOENT;
859 }
860
861 if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
862 char *name;
863
864 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
865 res = genl_family_find_byname(name);
866 #ifdef CONFIG_MODULES
867 if (res == NULL) {
868 genl_unlock();
869 up_read(&cb_lock);
870 request_module("net-pf-%d-proto-%d-family-%s",
871 PF_NETLINK, NETLINK_GENERIC, name);
872 down_read(&cb_lock);
873 genl_lock();
874 res = genl_family_find_byname(name);
875 }
876 #endif
877 err = -ENOENT;
878 }
879
880 if (res == NULL)
881 return err;
882
883 if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) {
884 /* family doesn't exist here */
885 return -ENOENT;
886 }
887
888 msg = ctrl_build_family_msg(res, info->snd_portid, info->snd_seq,
889 CTRL_CMD_NEWFAMILY);
890 if (IS_ERR(msg))
891 return PTR_ERR(msg);
892
893 return genlmsg_reply(msg, info);
894 }
895
896 static int genl_ctrl_event(int event, const struct genl_family *family,
897 const struct genl_multicast_group *grp,
898 int grp_id)
899 {
900 struct sk_buff *msg;
901
902 /* genl is still initialising */
903 if (!init_net.genl_sock)
904 return 0;
905
906 switch (event) {
907 case CTRL_CMD_NEWFAMILY:
908 case CTRL_CMD_DELFAMILY:
909 WARN_ON(grp);
910 msg = ctrl_build_family_msg(family, 0, 0, event);
911 break;
912 case CTRL_CMD_NEWMCAST_GRP:
913 case CTRL_CMD_DELMCAST_GRP:
914 BUG_ON(!grp);
915 msg = ctrl_build_mcgrp_msg(family, grp, grp_id, 0, 0, event);
916 break;
917 default:
918 return -EINVAL;
919 }
920
921 if (IS_ERR(msg))
922 return PTR_ERR(msg);
923
924 if (!family->netnsok) {
925 genlmsg_multicast_netns(&genl_ctrl, &init_net, msg, 0,
926 0, GFP_KERNEL);
927 } else {
928 rcu_read_lock();
929 genlmsg_multicast_allns(&genl_ctrl, msg, 0,
930 0, GFP_ATOMIC);
931 rcu_read_unlock();
932 }
933
934 return 0;
935 }
936
937 static const struct genl_ops genl_ctrl_ops[] = {
938 {
939 .cmd = CTRL_CMD_GETFAMILY,
940 .doit = ctrl_getfamily,
941 .dumpit = ctrl_dumpfamily,
942 .policy = ctrl_policy,
943 },
944 };
945
946 static const struct genl_multicast_group genl_ctrl_groups[] = {
947 { .name = "notify", },
948 };
949
950 static struct genl_family genl_ctrl __ro_after_init = {
951 .module = THIS_MODULE,
952 .ops = genl_ctrl_ops,
953 .n_ops = ARRAY_SIZE(genl_ctrl_ops),
954 .mcgrps = genl_ctrl_groups,
955 .n_mcgrps = ARRAY_SIZE(genl_ctrl_groups),
956 .id = GENL_ID_CTRL,
957 .name = "nlctrl",
958 .version = 0x2,
959 .maxattr = CTRL_ATTR_MAX,
960 .netnsok = true,
961 };
962
963 static int genl_bind(struct net *net, int group)
964 {
965 struct genl_family *f;
966 int err = -ENOENT;
967 unsigned int id;
968
969 down_read(&cb_lock);
970
971 idr_for_each_entry(&genl_fam_idr, f, id) {
972 if (group >= f->mcgrp_offset &&
973 group < f->mcgrp_offset + f->n_mcgrps) {
974 int fam_grp = group - f->mcgrp_offset;
975
976 if (!f->netnsok && net != &init_net)
977 err = -ENOENT;
978 else if (f->mcast_bind)
979 err = f->mcast_bind(net, fam_grp);
980 else
981 err = 0;
982 break;
983 }
984 }
985 up_read(&cb_lock);
986
987 return err;
988 }
989
990 static void genl_unbind(struct net *net, int group)
991 {
992 struct genl_family *f;
993 unsigned int id;
994
995 down_read(&cb_lock);
996
997 idr_for_each_entry(&genl_fam_idr, f, id) {
998 if (group >= f->mcgrp_offset &&
999 group < f->mcgrp_offset + f->n_mcgrps) {
1000 int fam_grp = group - f->mcgrp_offset;
1001
1002 if (f->mcast_unbind)
1003 f->mcast_unbind(net, fam_grp);
1004 break;
1005 }
1006 }
1007 up_read(&cb_lock);
1008 }
1009
1010 static int __net_init genl_pernet_init(struct net *net)
1011 {
1012 struct netlink_kernel_cfg cfg = {
1013 .input = genl_rcv,
1014 .flags = NL_CFG_F_NONROOT_RECV,
1015 .bind = genl_bind,
1016 .unbind = genl_unbind,
1017 };
1018
1019 /* we'll bump the group number right afterwards */
1020 net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg);
1021
1022 if (!net->genl_sock && net_eq(net, &init_net))
1023 panic("GENL: Cannot initialize generic netlink\n");
1024
1025 if (!net->genl_sock)
1026 return -ENOMEM;
1027
1028 return 0;
1029 }
1030
1031 static void __net_exit genl_pernet_exit(struct net *net)
1032 {
1033 netlink_kernel_release(net->genl_sock);
1034 net->genl_sock = NULL;
1035 }
1036
1037 static struct pernet_operations genl_pernet_ops = {
1038 .init = genl_pernet_init,
1039 .exit = genl_pernet_exit,
1040 };
1041
1042 static int __init genl_init(void)
1043 {
1044 int err;
1045
1046 err = genl_register_family(&genl_ctrl);
1047 if (err < 0)
1048 goto problem;
1049
1050 err = register_pernet_subsys(&genl_pernet_ops);
1051 if (err)
1052 goto problem;
1053
1054 return 0;
1055
1056 problem:
1057 panic("GENL: Cannot register controller: %d\n", err);
1058 }
1059
1060 subsys_initcall(genl_init);
1061
1062 /**
1063 * genl_family_attrbuf - return family's attrbuf
1064 * @family: the family
1065 *
1066 * Return the family's attrbuf, while validating that it's
1067 * actually valid to access it.
1068 *
1069 * You cannot use this function with a family that has parallel_ops
1070 * and you can only use it within (pre/post) doit/dumpit callbacks.
1071 */
1072 struct nlattr **genl_family_attrbuf(const struct genl_family *family)
1073 {
1074 if (!WARN_ON(family->parallel_ops))
1075 lockdep_assert_held(&genl_mutex);
1076
1077 return family->attrbuf;
1078 }
1079 EXPORT_SYMBOL(genl_family_attrbuf);
1080
1081 static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
1082 gfp_t flags)
1083 {
1084 struct sk_buff *tmp;
1085 struct net *net, *prev = NULL;
1086 bool delivered = false;
1087 int err;
1088
1089 for_each_net_rcu(net) {
1090 if (prev) {
1091 tmp = skb_clone(skb, flags);
1092 if (!tmp) {
1093 err = -ENOMEM;
1094 goto error;
1095 }
1096 err = nlmsg_multicast(prev->genl_sock, tmp,
1097 portid, group, flags);
1098 if (!err)
1099 delivered = true;
1100 else if (err != -ESRCH)
1101 goto error;
1102 }
1103
1104 prev = net;
1105 }
1106
1107 err = nlmsg_multicast(prev->genl_sock, skb, portid, group, flags);
1108 if (!err)
1109 delivered = true;
1110 else if (err != -ESRCH)
1111 return err;
1112 return delivered ? 0 : -ESRCH;
1113 error:
1114 kfree_skb(skb);
1115 return err;
1116 }
1117
1118 int genlmsg_multicast_allns(const struct genl_family *family,
1119 struct sk_buff *skb, u32 portid,
1120 unsigned int group, gfp_t flags)
1121 {
1122 if (WARN_ON_ONCE(group >= family->n_mcgrps))
1123 return -EINVAL;
1124 group = family->mcgrp_offset + group;
1125 return genlmsg_mcast(skb, portid, group, flags);
1126 }
1127 EXPORT_SYMBOL(genlmsg_multicast_allns);
1128
1129 void genl_notify(const struct genl_family *family, struct sk_buff *skb,
1130 struct genl_info *info, u32 group, gfp_t flags)
1131 {
1132 struct net *net = genl_info_net(info);
1133 struct sock *sk = net->genl_sock;
1134 int report = 0;
1135
1136 if (info->nlhdr)
1137 report = nlmsg_report(info->nlhdr);
1138
1139 if (WARN_ON_ONCE(group >= family->n_mcgrps))
1140 return;
1141 group = family->mcgrp_offset + group;
1142 nlmsg_notify(sk, skb, info->snd_portid, group, report, flags);
1143 }
1144 EXPORT_SYMBOL(genl_notify);
Linux with added FPC-III support