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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 <linux/rwsem.h>
20#include <linux/idr.h>
21#include <net/sock.h>
22#include <net/genetlink.h>
23
24static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */
25static DECLARE_RWSEM(cb_lock);
26
27atomic_t genl_sk_destructing_cnt = ATOMIC_INIT(0);
28DECLARE_WAIT_QUEUE_HEAD(genl_sk_destructing_waitq);
29
30void genl_lock(void)
31{
32 mutex_lock(&genl_mutex);
33}
34EXPORT_SYMBOL(genl_lock);
35
36void genl_unlock(void)
37{
38 mutex_unlock(&genl_mutex);
39}
40EXPORT_SYMBOL(genl_unlock);
41
42#ifdef CONFIG_LOCKDEP
43bool lockdep_genl_is_held(void)
44{
45 return lockdep_is_held(&genl_mutex);
46}
47EXPORT_SYMBOL(lockdep_genl_is_held);
48#endif
49
50static void genl_lock_all(void)
51{
52 down_write(&cb_lock);
53 genl_lock();
54}
55
56static void genl_unlock_all(void)
57{
58 genl_unlock();
59 up_write(&cb_lock);
60}
61
62static DEFINE_IDR(genl_fam_idr);
63
64/*
65 * Bitmap of multicast groups that are currently in use.
66 *
67 * To avoid an allocation at boot of just one unsigned long,
68 * declare it global instead.
69 * Bit 0 is marked as already used since group 0 is invalid.
70 * Bit 1 is marked as already used since the drop-monitor code
71 * abuses the API and thinks it can statically use group 1.
72 * That group will typically conflict with other groups that
73 * any proper users use.
74 * Bit 16 is marked as used since it's used for generic netlink
75 * and the code no longer marks pre-reserved IDs as used.
76 * Bit 17 is marked as already used since the VFS quota code
77 * also abused this API and relied on family == group ID, we
78 * cater to that by giving it a static family and group ID.
79 * Bit 18 is marked as already used since the PMCRAID driver
80 * did the same thing as the VFS quota code (maybe copied?)
81 */
82static unsigned long mc_group_start = 0x3 | BIT(GENL_ID_CTRL) |
83 BIT(GENL_ID_VFS_DQUOT) |
84 BIT(GENL_ID_PMCRAID);
85static unsigned long *mc_groups = &mc_group_start;
86static unsigned long mc_groups_longs = 1;
87
88static int genl_ctrl_event(int event, const struct genl_family *family,
89 const struct genl_multicast_group *grp,
90 int grp_id);
91
92static const struct genl_family *genl_family_find_byid(unsigned int id)
93{
94 return idr_find(&genl_fam_idr, id);
95}
96
97static const struct genl_family *genl_family_find_byname(char *name)
98{
99 const struct genl_family *family;
100 unsigned int id;
101
102 idr_for_each_entry(&genl_fam_idr, family, id)
103 if (strcmp(family->name, name) == 0)
104 return family;
105
106 return NULL;
107}
108
109static const struct genl_ops *genl_get_cmd(u8 cmd,
110 const struct genl_family *family)
111{
112 int i;
113
114 for (i = 0; i < family->n_ops; i++)
115 if (family->ops[i].cmd == cmd)
116 return &family->ops[i];
117
118 return NULL;
119}
120
121static int genl_allocate_reserve_groups(int n_groups, int *first_id)
122{
123 unsigned long *new_groups;
124 int start = 0;
125 int i;
126 int id;
127 bool fits;
128
129 do {
130 if (start == 0)
131 id = find_first_zero_bit(mc_groups,
132 mc_groups_longs *
133 BITS_PER_LONG);
134 else
135 id = find_next_zero_bit(mc_groups,
136 mc_groups_longs * BITS_PER_LONG,
137 start);
138
139 fits = true;
140 for (i = id;
141 i < min_t(int, id + n_groups,
142 mc_groups_longs * BITS_PER_LONG);
143 i++) {
144 if (test_bit(i, mc_groups)) {
145 start = i;
146 fits = false;
147 break;
148 }
149 }
150
151 if (id + n_groups > mc_groups_longs * BITS_PER_LONG) {
152 unsigned long new_longs = mc_groups_longs +
153 BITS_TO_LONGS(n_groups);
154 size_t nlen = new_longs * sizeof(unsigned long);
155
156 if (mc_groups == &mc_group_start) {
157 new_groups = kzalloc(nlen, GFP_KERNEL);
158 if (!new_groups)
159 return -ENOMEM;
160 mc_groups = new_groups;
161 *mc_groups = mc_group_start;
162 } else {
163 new_groups = krealloc(mc_groups, nlen,
164 GFP_KERNEL);
165 if (!new_groups)
166 return -ENOMEM;
167 mc_groups = new_groups;
168 for (i = 0; i < BITS_TO_LONGS(n_groups); i++)
169 mc_groups[mc_groups_longs + i] = 0;
170 }
171 mc_groups_longs = new_longs;
172 }
173 } while (!fits);
174
175 for (i = id; i < id + n_groups; i++)
176 set_bit(i, mc_groups);
177 *first_id = id;
178 return 0;
179}
180
181static struct genl_family genl_ctrl;
182
183static int genl_validate_assign_mc_groups(struct genl_family *family)
184{
185 int first_id;
186 int n_groups = family->n_mcgrps;
187 int err = 0, i;
188 bool groups_allocated = false;
189
190 if (!n_groups)
191 return 0;
192
193 for (i = 0; i < n_groups; i++) {
194 const struct genl_multicast_group *grp = &family->mcgrps[i];
195
196 if (WARN_ON(grp->name[0] == '\0'))
197 return -EINVAL;
198 if (WARN_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL))
199 return -EINVAL;
200 }
201
202 /* special-case our own group and hacks */
203 if (family == &genl_ctrl) {
204 first_id = GENL_ID_CTRL;
205 BUG_ON(n_groups != 1);
206 } else if (strcmp(family->name, "NET_DM") == 0) {
207 first_id = 1;
208 BUG_ON(n_groups != 1);
209 } else if (family->id == GENL_ID_VFS_DQUOT) {
210 first_id = GENL_ID_VFS_DQUOT;
211 BUG_ON(n_groups != 1);
212 } else if (family->id == GENL_ID_PMCRAID) {
213 first_id = GENL_ID_PMCRAID;
214 BUG_ON(n_groups != 1);
215 } else {
216 groups_allocated = true;
217 err = genl_allocate_reserve_groups(n_groups, &first_id);
218 if (err)
219 return err;
220 }
221
222 family->mcgrp_offset = first_id;
223
224 /* if still initializing, can't and don't need to to realloc bitmaps */
225 if (!init_net.genl_sock)
226 return 0;
227
228 if (family->netnsok) {
229 struct net *net;
230
231 netlink_table_grab();
232 rcu_read_lock();
233 for_each_net_rcu(net) {
234 err = __netlink_change_ngroups(net->genl_sock,
235 mc_groups_longs * BITS_PER_LONG);
236 if (err) {
237 /*
238 * No need to roll back, can only fail if
239 * memory allocation fails and then the
240 * number of _possible_ groups has been
241 * increased on some sockets which is ok.
242 */
243 break;
244 }
245 }
246 rcu_read_unlock();
247 netlink_table_ungrab();
248 } else {
249 err = netlink_change_ngroups(init_net.genl_sock,
250 mc_groups_longs * BITS_PER_LONG);
251 }
252
253 if (groups_allocated && err) {
254 for (i = 0; i < family->n_mcgrps; i++)
255 clear_bit(family->mcgrp_offset + i, mc_groups);
256 }
257
258 return err;
259}
260
261static void genl_unregister_mc_groups(const struct genl_family *family)
262{
263 struct net *net;
264 int i;
265
266 netlink_table_grab();
267 rcu_read_lock();
268 for_each_net_rcu(net) {
269 for (i = 0; i < family->n_mcgrps; i++)
270 __netlink_clear_multicast_users(
271 net->genl_sock, family->mcgrp_offset + i);
272 }
273 rcu_read_unlock();
274 netlink_table_ungrab();
275
276 for (i = 0; i < family->n_mcgrps; i++) {
277 int grp_id = family->mcgrp_offset + i;
278
279 if (grp_id != 1)
280 clear_bit(grp_id, mc_groups);
281 genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, family,
282 &family->mcgrps[i], grp_id);
283 }
284}
285
286static int genl_validate_ops(const struct genl_family *family)
287{
288 const struct genl_ops *ops = family->ops;
289 unsigned int n_ops = family->n_ops;
290 int i, j;
291
292 if (WARN_ON(n_ops && !ops))
293 return -EINVAL;
294
295 if (!n_ops)
296 return 0;
297
298 for (i = 0; i < n_ops; i++) {
299 if (ops[i].dumpit == NULL && ops[i].doit == NULL)
300 return -EINVAL;
301 for (j = i + 1; j < n_ops; j++)
302 if (ops[i].cmd == ops[j].cmd)
303 return -EINVAL;
304 }
305
306 return 0;
307}
308
309/**
310 * genl_register_family - register a generic netlink family
311 * @family: generic netlink family
312 *
313 * Registers the specified family after validating it first. Only one
314 * family may be registered with the same family name or identifier.
315 *
316 * The family's ops, multicast groups and module pointer must already
317 * be assigned.
318 *
319 * Return 0 on success or a negative error code.
320 */
321int genl_register_family(struct genl_family *family)
322{
323 int err, i;
324 int start = GENL_START_ALLOC, end = GENL_MAX_ID;
325
326 err = genl_validate_ops(family);
327 if (err)
328 return err;
329
330 genl_lock_all();
331
332 if (genl_family_find_byname(family->name)) {
333 err = -EEXIST;
334 goto errout_locked;
335 }
336
337 /*
338 * Sadly, a few cases need to be special-cased
339 * due to them having previously abused the API
340 * and having used their family ID also as their
341 * multicast group ID, so we use reserved IDs
342 * for both to be sure we can do that mapping.
343 */
344 if (family == &genl_ctrl) {
345 /* and this needs to be special for initial family lookups */
346 start = end = GENL_ID_CTRL;
347 } else if (strcmp(family->name, "pmcraid") == 0) {
348 start = end = GENL_ID_PMCRAID;
349 } else if (strcmp(family->name, "VFS_DQUOT") == 0) {
350 start = end = GENL_ID_VFS_DQUOT;
351 }
352
353 if (family->maxattr && !family->parallel_ops) {
354 family->attrbuf = kmalloc((family->maxattr+1) *
355 sizeof(struct nlattr *), GFP_KERNEL);
356 if (family->attrbuf == NULL) {
357 err = -ENOMEM;
358 goto errout_locked;
359 }
360 } else
361 family->attrbuf = NULL;
362
363 family->id = idr_alloc(&genl_fam_idr, family,
364 start, end + 1, GFP_KERNEL);
365 if (family->id < 0) {
366 err = family->id;
367 goto errout_locked;
368 }
369
370 err = genl_validate_assign_mc_groups(family);
371 if (err)
372 goto errout_remove;
373
374 genl_unlock_all();
375
376 /* send all events */
377 genl_ctrl_event(CTRL_CMD_NEWFAMILY, family, NULL, 0);
378 for (i = 0; i < family->n_mcgrps; i++)
379 genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, family,
380 &family->mcgrps[i], family->mcgrp_offset + i);
381
382 return 0;
383
384errout_remove:
385 idr_remove(&genl_fam_idr, family->id);
386 kfree(family->attrbuf);
387errout_locked:
388 genl_unlock_all();
389 return err;
390}
391EXPORT_SYMBOL(genl_register_family);
392
393/**
394 * genl_unregister_family - unregister generic netlink family
395 * @family: generic netlink family
396 *
397 * Unregisters the specified family.
398 *
399 * Returns 0 on success or a negative error code.
400 */
401int genl_unregister_family(const struct genl_family *family)
402{
403 genl_lock_all();
404
405 if (!genl_family_find_byid(family->id)) {
406 genl_unlock_all();
407 return -ENOENT;
408 }
409
410 genl_unregister_mc_groups(family);
411
412 idr_remove(&genl_fam_idr, family->id);
413
414 up_write(&cb_lock);
415 wait_event(genl_sk_destructing_waitq,
416 atomic_read(&genl_sk_destructing_cnt) == 0);
417 genl_unlock();
418
419 kfree(family->attrbuf);
420
421 genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 0);
422
423 return 0;
424}
425EXPORT_SYMBOL(genl_unregister_family);
426
427/**
428 * genlmsg_put - Add generic netlink header to netlink message
429 * @skb: socket buffer holding the message
430 * @portid: netlink portid the message is addressed to
431 * @seq: sequence number (usually the one of the sender)
432 * @family: generic netlink family
433 * @flags: netlink message flags
434 * @cmd: generic netlink command
435 *
436 * Returns pointer to user specific header
437 */
438void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
439 const struct genl_family *family, int flags, u8 cmd)
440{
441 struct nlmsghdr *nlh;
442 struct genlmsghdr *hdr;
443
444 nlh = nlmsg_put(skb, portid, seq, family->id, GENL_HDRLEN +
445 family->hdrsize, flags);
446 if (nlh == NULL)
447 return NULL;
448
449 hdr = nlmsg_data(nlh);
450 hdr->cmd = cmd;
451 hdr->version = family->version;
452 hdr->reserved = 0;
453
454 return (char *) hdr + GENL_HDRLEN;
455}
456EXPORT_SYMBOL(genlmsg_put);
457
458static int genl_lock_start(struct netlink_callback *cb)
459{
460 /* our ops are always const - netlink API doesn't propagate that */
461 const struct genl_ops *ops = cb->data;
462 int rc = 0;
463
464 if (ops->start) {
465 genl_lock();
466 rc = ops->start(cb);
467 genl_unlock();
468 }
469 return rc;
470}
471
472static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
473{
474 /* our ops are always const - netlink API doesn't propagate that */
475 const struct genl_ops *ops = cb->data;
476 int rc;
477
478 genl_lock();
479 rc = ops->dumpit(skb, cb);
480 genl_unlock();
481 return rc;
482}
483
484static int genl_lock_done(struct netlink_callback *cb)
485{
486 /* our ops are always const - netlink API doesn't propagate that */
487 const struct genl_ops *ops = cb->data;
488 int rc = 0;
489
490 if (ops->done) {
491 genl_lock();
492 rc = ops->done(cb);
493 genl_unlock();
494 }
495 return rc;
496}
497
498static int genl_family_rcv_msg(const struct genl_family *family,
499 struct sk_buff *skb,
500 struct nlmsghdr *nlh)
501{
502 const struct genl_ops *ops;
503 struct net *net = sock_net(skb->sk);
504 struct genl_info info;
505 struct genlmsghdr *hdr = nlmsg_data(nlh);
506 struct nlattr **attrbuf;
507 int hdrlen, err;
508
509 /* this family doesn't exist in this netns */
510 if (!family->netnsok && !net_eq(net, &init_net))
511 return -ENOENT;
512
513 hdrlen = GENL_HDRLEN + family->hdrsize;
514 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
515 return -EINVAL;
516
517 ops = genl_get_cmd(hdr->cmd, family);
518 if (ops == NULL)
519 return -EOPNOTSUPP;
520
521 if ((ops->flags & GENL_ADMIN_PERM) &&
522 !netlink_capable(skb, CAP_NET_ADMIN))
523 return -EPERM;
524
525 if ((ops->flags & GENL_UNS_ADMIN_PERM) &&
526 !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
527 return -EPERM;
528
529 if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP) {
530 int rc;
531
532 if (ops->dumpit == NULL)
533 return -EOPNOTSUPP;
534
535 if (!family->parallel_ops) {
536 struct netlink_dump_control c = {
537 .module = family->module,
538 /* we have const, but the netlink API doesn't */
539 .data = (void *)ops,
540 .start = genl_lock_start,
541 .dump = genl_lock_dumpit,
542 .done = genl_lock_done,
543 };
544
545 genl_unlock();
546 rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
547 genl_lock();
548
549 } else {
550 struct netlink_dump_control c = {
551 .module = family->module,
552 .start = ops->start,
553 .dump = ops->dumpit,
554 .done = ops->done,
555 };
556
557 rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
558 }
559
560 return rc;
561 }
562
563 if (ops->doit == NULL)
564 return -EOPNOTSUPP;
565
566 if (family->maxattr && family->parallel_ops) {
567 attrbuf = kmalloc((family->maxattr+1) *
568 sizeof(struct nlattr *), GFP_KERNEL);
569 if (attrbuf == NULL)
570 return -ENOMEM;
571 } else
572 attrbuf = family->attrbuf;
573
574 if (attrbuf) {
575 err = nlmsg_parse(nlh, hdrlen, attrbuf, family->maxattr,
576 ops->policy);
577 if (err < 0)
578 goto out;
579 }
580
581 info.snd_seq = nlh->nlmsg_seq;
582 info.snd_portid = NETLINK_CB(skb).portid;
583 info.nlhdr = nlh;
584 info.genlhdr = nlmsg_data(nlh);
585 info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
586 info.attrs = attrbuf;
587 genl_info_net_set(&info, net);
588 memset(&info.user_ptr, 0, sizeof(info.user_ptr));
589
590 if (family->pre_doit) {
591 err = family->pre_doit(ops, skb, &info);
592 if (err)
593 goto out;
594 }
595
596 err = ops->doit(skb, &info);
597
598 if (family->post_doit)
599 family->post_doit(ops, skb, &info);
600
601out:
602 if (family->parallel_ops)
603 kfree(attrbuf);
604
605 return err;
606}
607
608static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
609{
610 const struct genl_family *family;
611 int err;
612
613 family = genl_family_find_byid(nlh->nlmsg_type);
614 if (family == NULL)
615 return -ENOENT;
616
617 if (!family->parallel_ops)
618 genl_lock();
619
620 err = genl_family_rcv_msg(family, skb, nlh);
621
622 if (!family->parallel_ops)
623 genl_unlock();
624
625 return err;
626}
627
628static void genl_rcv(struct sk_buff *skb)
629{
630 down_read(&cb_lock);
631 netlink_rcv_skb(skb, &genl_rcv_msg);
632 up_read(&cb_lock);
633}
634
635/**************************************************************************
636 * Controller
637 **************************************************************************/
638
639static struct genl_family genl_ctrl;
640
641static int ctrl_fill_info(const struct genl_family *family, u32 portid, u32 seq,
642 u32 flags, struct sk_buff *skb, u8 cmd)
643{
644 void *hdr;
645
646 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
647 if (hdr == NULL)
648 return -1;
649
650 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
651 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) ||
652 nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) ||
653 nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) ||
654 nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr))
655 goto nla_put_failure;
656
657 if (family->n_ops) {
658 struct nlattr *nla_ops;
659 int i;
660
661 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
662 if (nla_ops == NULL)
663 goto nla_put_failure;
664
665 for (i = 0; i < family->n_ops; i++) {
666 struct nlattr *nest;
667 const struct genl_ops *ops = &family->ops[i];
668 u32 op_flags = ops->flags;
669
670 if (ops->dumpit)
671 op_flags |= GENL_CMD_CAP_DUMP;
672 if (ops->doit)
673 op_flags |= GENL_CMD_CAP_DO;
674 if (ops->policy)
675 op_flags |= GENL_CMD_CAP_HASPOL;
676
677 nest = nla_nest_start(skb, i + 1);
678 if (nest == NULL)
679 goto nla_put_failure;
680
681 if (nla_put_u32(skb, CTRL_ATTR_OP_ID, ops->cmd) ||
682 nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, op_flags))
683 goto nla_put_failure;
684
685 nla_nest_end(skb, nest);
686 }
687
688 nla_nest_end(skb, nla_ops);
689 }
690
691 if (family->n_mcgrps) {
692 struct nlattr *nla_grps;
693 int i;
694
695 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
696 if (nla_grps == NULL)
697 goto nla_put_failure;
698
699 for (i = 0; i < family->n_mcgrps; i++) {
700 struct nlattr *nest;
701 const struct genl_multicast_group *grp;
702
703 grp = &family->mcgrps[i];
704
705 nest = nla_nest_start(skb, i + 1);
706 if (nest == NULL)
707 goto nla_put_failure;
708
709 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID,
710 family->mcgrp_offset + i) ||
711 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
712 grp->name))
713 goto nla_put_failure;
714
715 nla_nest_end(skb, nest);
716 }
717 nla_nest_end(skb, nla_grps);
718 }
719
720 genlmsg_end(skb, hdr);
721 return 0;
722
723nla_put_failure:
724 genlmsg_cancel(skb, hdr);
725 return -EMSGSIZE;
726}
727
728static int ctrl_fill_mcgrp_info(const struct genl_family *family,
729 const struct genl_multicast_group *grp,
730 int grp_id, u32 portid, u32 seq, u32 flags,
731 struct sk_buff *skb, u8 cmd)
732{
733 void *hdr;
734 struct nlattr *nla_grps;
735 struct nlattr *nest;
736
737 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
738 if (hdr == NULL)
739 return -1;
740
741 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
742 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id))
743 goto nla_put_failure;
744
745 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
746 if (nla_grps == NULL)
747 goto nla_put_failure;
748
749 nest = nla_nest_start(skb, 1);
750 if (nest == NULL)
751 goto nla_put_failure;
752
753 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp_id) ||
754 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
755 grp->name))
756 goto nla_put_failure;
757
758 nla_nest_end(skb, nest);
759 nla_nest_end(skb, nla_grps);
760
761 genlmsg_end(skb, hdr);
762 return 0;
763
764nla_put_failure:
765 genlmsg_cancel(skb, hdr);
766 return -EMSGSIZE;
767}
768
769static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
770{
771 int n = 0;
772 struct genl_family *rt;
773 struct net *net = sock_net(skb->sk);
774 int fams_to_skip = cb->args[0];
775 unsigned int id;
776
777 idr_for_each_entry(&genl_fam_idr, rt, id) {
778 if (!rt->netnsok && !net_eq(net, &init_net))
779 continue;
780
781 if (n++ < fams_to_skip)
782 continue;
783
784 if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid,
785 cb->nlh->nlmsg_seq, NLM_F_MULTI,
786 skb, CTRL_CMD_NEWFAMILY) < 0) {
787 n--;
788 break;
789 }
790 }
791
792 cb->args[0] = n;
793 return skb->len;
794}
795
796static struct sk_buff *ctrl_build_family_msg(const struct genl_family *family,
797 u32 portid, int seq, u8 cmd)
798{
799 struct sk_buff *skb;
800 int err;
801
802 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
803 if (skb == NULL)
804 return ERR_PTR(-ENOBUFS);
805
806 err = ctrl_fill_info(family, portid, seq, 0, skb, cmd);
807 if (err < 0) {
808 nlmsg_free(skb);
809 return ERR_PTR(err);
810 }
811
812 return skb;
813}
814
815static struct sk_buff *
816ctrl_build_mcgrp_msg(const struct genl_family *family,
817 const struct genl_multicast_group *grp,
818 int grp_id, u32 portid, int seq, u8 cmd)
819{
820 struct sk_buff *skb;
821 int err;
822
823 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
824 if (skb == NULL)
825 return ERR_PTR(-ENOBUFS);
826
827 err = ctrl_fill_mcgrp_info(family, grp, grp_id, portid,
828 seq, 0, skb, cmd);
829 if (err < 0) {
830 nlmsg_free(skb);
831 return ERR_PTR(err);
832 }
833
834 return skb;
835}
836
837static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
838 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 },
839 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
840 .len = GENL_NAMSIZ - 1 },
841};
842
843static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
844{
845 struct sk_buff *msg;
846 const struct genl_family *res = NULL;
847 int err = -EINVAL;
848
849 if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
850 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
851 res = genl_family_find_byid(id);
852 err = -ENOENT;
853 }
854
855 if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
856 char *name;
857
858 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
859 res = genl_family_find_byname(name);
860#ifdef CONFIG_MODULES
861 if (res == NULL) {
862 genl_unlock();
863 up_read(&cb_lock);
864 request_module("net-pf-%d-proto-%d-family-%s",
865 PF_NETLINK, NETLINK_GENERIC, name);
866 down_read(&cb_lock);
867 genl_lock();
868 res = genl_family_find_byname(name);
869 }
870#endif
871 err = -ENOENT;
872 }
873
874 if (res == NULL)
875 return err;
876
877 if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) {
878 /* family doesn't exist here */
879 return -ENOENT;
880 }
881
882 msg = ctrl_build_family_msg(res, info->snd_portid, info->snd_seq,
883 CTRL_CMD_NEWFAMILY);
884 if (IS_ERR(msg))
885 return PTR_ERR(msg);
886
887 return genlmsg_reply(msg, info);
888}
889
890static int genl_ctrl_event(int event, const struct genl_family *family,
891 const struct genl_multicast_group *grp,
892 int grp_id)
893{
894 struct sk_buff *msg;
895
896 /* genl is still initialising */
897 if (!init_net.genl_sock)
898 return 0;
899
900 switch (event) {
901 case CTRL_CMD_NEWFAMILY:
902 case CTRL_CMD_DELFAMILY:
903 WARN_ON(grp);
904 msg = ctrl_build_family_msg(family, 0, 0, event);
905 break;
906 case CTRL_CMD_NEWMCAST_GRP:
907 case CTRL_CMD_DELMCAST_GRP:
908 BUG_ON(!grp);
909 msg = ctrl_build_mcgrp_msg(family, grp, grp_id, 0, 0, event);
910 break;
911 default:
912 return -EINVAL;
913 }
914
915 if (IS_ERR(msg))
916 return PTR_ERR(msg);
917
918 if (!family->netnsok) {
919 genlmsg_multicast_netns(&genl_ctrl, &init_net, msg, 0,
920 0, GFP_KERNEL);
921 } else {
922 rcu_read_lock();
923 genlmsg_multicast_allns(&genl_ctrl, msg, 0,
924 0, GFP_ATOMIC);
925 rcu_read_unlock();
926 }
927
928 return 0;
929}
930
931static const struct genl_ops genl_ctrl_ops[] = {
932 {
933 .cmd = CTRL_CMD_GETFAMILY,
934 .doit = ctrl_getfamily,
935 .dumpit = ctrl_dumpfamily,
936 .policy = ctrl_policy,
937 },
938};
939
940static const struct genl_multicast_group genl_ctrl_groups[] = {
941 { .name = "notify", },
942};
943
944static struct genl_family genl_ctrl __ro_after_init = {
945 .module = THIS_MODULE,
946 .ops = genl_ctrl_ops,
947 .n_ops = ARRAY_SIZE(genl_ctrl_ops),
948 .mcgrps = genl_ctrl_groups,
949 .n_mcgrps = ARRAY_SIZE(genl_ctrl_groups),
950 .id = GENL_ID_CTRL,
951 .name = "nlctrl",
952 .version = 0x2,
953 .maxattr = CTRL_ATTR_MAX,
954 .netnsok = true,
955};
956
957static int genl_bind(struct net *net, int group)
958{
959 struct genl_family *f;
960 int err = -ENOENT;
961 unsigned int id;
962
963 down_read(&cb_lock);
964
965 idr_for_each_entry(&genl_fam_idr, f, id) {
966 if (group >= f->mcgrp_offset &&
967 group < f->mcgrp_offset + f->n_mcgrps) {
968 int fam_grp = group - f->mcgrp_offset;
969
970 if (!f->netnsok && net != &init_net)
971 err = -ENOENT;
972 else if (f->mcast_bind)
973 err = f->mcast_bind(net, fam_grp);
974 else
975 err = 0;
976 break;
977 }
978 }
979 up_read(&cb_lock);
980
981 return err;
982}
983
984static void genl_unbind(struct net *net, int group)
985{
986 struct genl_family *f;
987 unsigned int id;
988
989 down_read(&cb_lock);
990
991 idr_for_each_entry(&genl_fam_idr, f, id) {
992 if (group >= f->mcgrp_offset &&
993 group < f->mcgrp_offset + f->n_mcgrps) {
994 int fam_grp = group - f->mcgrp_offset;
995
996 if (f->mcast_unbind)
997 f->mcast_unbind(net, fam_grp);
998 break;
999 }
1000 }
1001 up_read(&cb_lock);
1002}
1003
1004static int __net_init genl_pernet_init(struct net *net)
1005{
1006 struct netlink_kernel_cfg cfg = {
1007 .input = genl_rcv,
1008 .flags = NL_CFG_F_NONROOT_RECV,
1009 .bind = genl_bind,
1010 .unbind = genl_unbind,
1011 };
1012
1013 /* we'll bump the group number right afterwards */
1014 net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg);
1015
1016 if (!net->genl_sock && net_eq(net, &init_net))
1017 panic("GENL: Cannot initialize generic netlink\n");
1018
1019 if (!net->genl_sock)
1020 return -ENOMEM;
1021
1022 return 0;
1023}
1024
1025static void __net_exit genl_pernet_exit(struct net *net)
1026{
1027 netlink_kernel_release(net->genl_sock);
1028 net->genl_sock = NULL;
1029}
1030
1031static struct pernet_operations genl_pernet_ops = {
1032 .init = genl_pernet_init,
1033 .exit = genl_pernet_exit,
1034};
1035
1036static int __init genl_init(void)
1037{
1038 int err;
1039
1040 err = genl_register_family(&genl_ctrl);
1041 if (err < 0)
1042 goto problem;
1043
1044 err = register_pernet_subsys(&genl_pernet_ops);
1045 if (err)
1046 goto problem;
1047
1048 return 0;
1049
1050problem:
1051 panic("GENL: Cannot register controller: %d\n", err);
1052}
1053
1054subsys_initcall(genl_init);
1055
1056/**
1057 * genl_family_attrbuf - return family's attrbuf
1058 * @family: the family
1059 *
1060 * Return the family's attrbuf, while validating that it's
1061 * actually valid to access it.
1062 *
1063 * You cannot use this function with a family that has parallel_ops
1064 * and you can only use it within (pre/post) doit/dumpit callbacks.
1065 */
1066struct nlattr **genl_family_attrbuf(const struct genl_family *family)
1067{
1068 if (!WARN_ON(family->parallel_ops))
1069 lockdep_assert_held(&genl_mutex);
1070
1071 return family->attrbuf;
1072}
1073EXPORT_SYMBOL(genl_family_attrbuf);
1074
1075static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
1076 gfp_t flags)
1077{
1078 struct sk_buff *tmp;
1079 struct net *net, *prev = NULL;
1080 int err;
1081
1082 for_each_net_rcu(net) {
1083 if (prev) {
1084 tmp = skb_clone(skb, flags);
1085 if (!tmp) {
1086 err = -ENOMEM;
1087 goto error;
1088 }
1089 err = nlmsg_multicast(prev->genl_sock, tmp,
1090 portid, group, flags);
1091 if (err)
1092 goto error;
1093 }
1094
1095 prev = net;
1096 }
1097
1098 return nlmsg_multicast(prev->genl_sock, skb, portid, group, flags);
1099 error:
1100 kfree_skb(skb);
1101 return err;
1102}
1103
1104int genlmsg_multicast_allns(const struct genl_family *family,
1105 struct sk_buff *skb, u32 portid,
1106 unsigned int group, gfp_t flags)
1107{
1108 if (WARN_ON_ONCE(group >= family->n_mcgrps))
1109 return -EINVAL;
1110 group = family->mcgrp_offset + group;
1111 return genlmsg_mcast(skb, portid, group, flags);
1112}
1113EXPORT_SYMBOL(genlmsg_multicast_allns);
1114
1115void genl_notify(const struct genl_family *family, struct sk_buff *skb,
1116 struct genl_info *info, u32 group, gfp_t flags)
1117{
1118 struct net *net = genl_info_net(info);
1119 struct sock *sk = net->genl_sock;
1120 int report = 0;
1121
1122 if (info->nlhdr)
1123 report = nlmsg_report(info->nlhdr);
1124
1125 if (WARN_ON_ONCE(group >= family->n_mcgrps))
1126 return;
1127 group = family->mcgrp_offset + group;
1128 nlmsg_notify(sk, skb, info->snd_portid, group, report, flags);
1129}
1130EXPORT_SYMBOL(genl_notify);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * NETLINK Generic Netlink Family
4 *
5 * Authors: Jamal Hadi Salim
6 * Thomas Graf <tgraf@suug.ch>
7 * Johannes Berg <johannes@sipsolutions.net>
8 */
9
10#include <linux/module.h>
11#include <linux/kernel.h>
12#include <linux/slab.h>
13#include <linux/errno.h>
14#include <linux/types.h>
15#include <linux/socket.h>
16#include <linux/string.h>
17#include <linux/skbuff.h>
18#include <linux/mutex.h>
19#include <linux/bitmap.h>
20#include <linux/rwsem.h>
21#include <linux/idr.h>
22#include <net/sock.h>
23#include <net/genetlink.h>
24
25static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */
26static DECLARE_RWSEM(cb_lock);
27
28atomic_t genl_sk_destructing_cnt = ATOMIC_INIT(0);
29DECLARE_WAIT_QUEUE_HEAD(genl_sk_destructing_waitq);
30
31void genl_lock(void)
32{
33 mutex_lock(&genl_mutex);
34}
35EXPORT_SYMBOL(genl_lock);
36
37void genl_unlock(void)
38{
39 mutex_unlock(&genl_mutex);
40}
41EXPORT_SYMBOL(genl_unlock);
42
43#ifdef CONFIG_LOCKDEP
44bool lockdep_genl_is_held(void)
45{
46 return lockdep_is_held(&genl_mutex);
47}
48EXPORT_SYMBOL(lockdep_genl_is_held);
49#endif
50
51static void genl_lock_all(void)
52{
53 down_write(&cb_lock);
54 genl_lock();
55}
56
57static void genl_unlock_all(void)
58{
59 genl_unlock();
60 up_write(&cb_lock);
61}
62
63static DEFINE_IDR(genl_fam_idr);
64
65/*
66 * Bitmap of multicast groups that are currently in use.
67 *
68 * To avoid an allocation at boot of just one unsigned long,
69 * declare it global instead.
70 * Bit 0 is marked as already used since group 0 is invalid.
71 * Bit 1 is marked as already used since the drop-monitor code
72 * abuses the API and thinks it can statically use group 1.
73 * That group will typically conflict with other groups that
74 * any proper users use.
75 * Bit 16 is marked as used since it's used for generic netlink
76 * and the code no longer marks pre-reserved IDs as used.
77 * Bit 17 is marked as already used since the VFS quota code
78 * also abused this API and relied on family == group ID, we
79 * cater to that by giving it a static family and group ID.
80 * Bit 18 is marked as already used since the PMCRAID driver
81 * did the same thing as the VFS quota code (maybe copied?)
82 */
83static unsigned long mc_group_start = 0x3 | BIT(GENL_ID_CTRL) |
84 BIT(GENL_ID_VFS_DQUOT) |
85 BIT(GENL_ID_PMCRAID);
86static unsigned long *mc_groups = &mc_group_start;
87static unsigned long mc_groups_longs = 1;
88
89static int genl_ctrl_event(int event, const struct genl_family *family,
90 const struct genl_multicast_group *grp,
91 int grp_id);
92
93static const struct genl_family *genl_family_find_byid(unsigned int id)
94{
95 return idr_find(&genl_fam_idr, id);
96}
97
98static const struct genl_family *genl_family_find_byname(char *name)
99{
100 const struct genl_family *family;
101 unsigned int id;
102
103 idr_for_each_entry(&genl_fam_idr, family, id)
104 if (strcmp(family->name, name) == 0)
105 return family;
106
107 return NULL;
108}
109
110static const struct genl_ops *genl_get_cmd(u8 cmd,
111 const struct genl_family *family)
112{
113 int i;
114
115 for (i = 0; i < family->n_ops; i++)
116 if (family->ops[i].cmd == cmd)
117 return &family->ops[i];
118
119 return NULL;
120}
121
122static int genl_allocate_reserve_groups(int n_groups, int *first_id)
123{
124 unsigned long *new_groups;
125 int start = 0;
126 int i;
127 int id;
128 bool fits;
129
130 do {
131 if (start == 0)
132 id = find_first_zero_bit(mc_groups,
133 mc_groups_longs *
134 BITS_PER_LONG);
135 else
136 id = find_next_zero_bit(mc_groups,
137 mc_groups_longs * BITS_PER_LONG,
138 start);
139
140 fits = true;
141 for (i = id;
142 i < min_t(int, id + n_groups,
143 mc_groups_longs * BITS_PER_LONG);
144 i++) {
145 if (test_bit(i, mc_groups)) {
146 start = i;
147 fits = false;
148 break;
149 }
150 }
151
152 if (id + n_groups > mc_groups_longs * BITS_PER_LONG) {
153 unsigned long new_longs = mc_groups_longs +
154 BITS_TO_LONGS(n_groups);
155 size_t nlen = new_longs * sizeof(unsigned long);
156
157 if (mc_groups == &mc_group_start) {
158 new_groups = kzalloc(nlen, GFP_KERNEL);
159 if (!new_groups)
160 return -ENOMEM;
161 mc_groups = new_groups;
162 *mc_groups = mc_group_start;
163 } else {
164 new_groups = krealloc(mc_groups, nlen,
165 GFP_KERNEL);
166 if (!new_groups)
167 return -ENOMEM;
168 mc_groups = new_groups;
169 for (i = 0; i < BITS_TO_LONGS(n_groups); i++)
170 mc_groups[mc_groups_longs + i] = 0;
171 }
172 mc_groups_longs = new_longs;
173 }
174 } while (!fits);
175
176 for (i = id; i < id + n_groups; i++)
177 set_bit(i, mc_groups);
178 *first_id = id;
179 return 0;
180}
181
182static struct genl_family genl_ctrl;
183
184static int genl_validate_assign_mc_groups(struct genl_family *family)
185{
186 int first_id;
187 int n_groups = family->n_mcgrps;
188 int err = 0, i;
189 bool groups_allocated = false;
190
191 if (!n_groups)
192 return 0;
193
194 for (i = 0; i < n_groups; i++) {
195 const struct genl_multicast_group *grp = &family->mcgrps[i];
196
197 if (WARN_ON(grp->name[0] == '\0'))
198 return -EINVAL;
199 if (WARN_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL))
200 return -EINVAL;
201 }
202
203 /* special-case our own group and hacks */
204 if (family == &genl_ctrl) {
205 first_id = GENL_ID_CTRL;
206 BUG_ON(n_groups != 1);
207 } else if (strcmp(family->name, "NET_DM") == 0) {
208 first_id = 1;
209 BUG_ON(n_groups != 1);
210 } else if (family->id == GENL_ID_VFS_DQUOT) {
211 first_id = GENL_ID_VFS_DQUOT;
212 BUG_ON(n_groups != 1);
213 } else if (family->id == GENL_ID_PMCRAID) {
214 first_id = GENL_ID_PMCRAID;
215 BUG_ON(n_groups != 1);
216 } else {
217 groups_allocated = true;
218 err = genl_allocate_reserve_groups(n_groups, &first_id);
219 if (err)
220 return err;
221 }
222
223 family->mcgrp_offset = first_id;
224
225 /* if still initializing, can't and don't need to to realloc bitmaps */
226 if (!init_net.genl_sock)
227 return 0;
228
229 if (family->netnsok) {
230 struct net *net;
231
232 netlink_table_grab();
233 rcu_read_lock();
234 for_each_net_rcu(net) {
235 err = __netlink_change_ngroups(net->genl_sock,
236 mc_groups_longs * BITS_PER_LONG);
237 if (err) {
238 /*
239 * No need to roll back, can only fail if
240 * memory allocation fails and then the
241 * number of _possible_ groups has been
242 * increased on some sockets which is ok.
243 */
244 break;
245 }
246 }
247 rcu_read_unlock();
248 netlink_table_ungrab();
249 } else {
250 err = netlink_change_ngroups(init_net.genl_sock,
251 mc_groups_longs * BITS_PER_LONG);
252 }
253
254 if (groups_allocated && err) {
255 for (i = 0; i < family->n_mcgrps; i++)
256 clear_bit(family->mcgrp_offset + i, mc_groups);
257 }
258
259 return err;
260}
261
262static void genl_unregister_mc_groups(const struct genl_family *family)
263{
264 struct net *net;
265 int i;
266
267 netlink_table_grab();
268 rcu_read_lock();
269 for_each_net_rcu(net) {
270 for (i = 0; i < family->n_mcgrps; i++)
271 __netlink_clear_multicast_users(
272 net->genl_sock, family->mcgrp_offset + i);
273 }
274 rcu_read_unlock();
275 netlink_table_ungrab();
276
277 for (i = 0; i < family->n_mcgrps; i++) {
278 int grp_id = family->mcgrp_offset + i;
279
280 if (grp_id != 1)
281 clear_bit(grp_id, mc_groups);
282 genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, family,
283 &family->mcgrps[i], grp_id);
284 }
285}
286
287static int genl_validate_ops(const struct genl_family *family)
288{
289 const struct genl_ops *ops = family->ops;
290 unsigned int n_ops = family->n_ops;
291 int i, j;
292
293 if (WARN_ON(n_ops && !ops))
294 return -EINVAL;
295
296 if (!n_ops)
297 return 0;
298
299 for (i = 0; i < n_ops; i++) {
300 if (ops[i].dumpit == NULL && ops[i].doit == NULL)
301 return -EINVAL;
302 for (j = i + 1; j < n_ops; j++)
303 if (ops[i].cmd == ops[j].cmd)
304 return -EINVAL;
305 }
306
307 return 0;
308}
309
310/**
311 * genl_register_family - register a generic netlink family
312 * @family: generic netlink family
313 *
314 * Registers the specified family after validating it first. Only one
315 * family may be registered with the same family name or identifier.
316 *
317 * The family's ops, multicast groups and module pointer must already
318 * be assigned.
319 *
320 * Return 0 on success or a negative error code.
321 */
322int genl_register_family(struct genl_family *family)
323{
324 int err, i;
325 int start = GENL_START_ALLOC, end = GENL_MAX_ID;
326
327 err = genl_validate_ops(family);
328 if (err)
329 return err;
330
331 genl_lock_all();
332
333 if (genl_family_find_byname(family->name)) {
334 err = -EEXIST;
335 goto errout_locked;
336 }
337
338 /*
339 * Sadly, a few cases need to be special-cased
340 * due to them having previously abused the API
341 * and having used their family ID also as their
342 * multicast group ID, so we use reserved IDs
343 * for both to be sure we can do that mapping.
344 */
345 if (family == &genl_ctrl) {
346 /* and this needs to be special for initial family lookups */
347 start = end = GENL_ID_CTRL;
348 } else if (strcmp(family->name, "pmcraid") == 0) {
349 start = end = GENL_ID_PMCRAID;
350 } else if (strcmp(family->name, "VFS_DQUOT") == 0) {
351 start = end = GENL_ID_VFS_DQUOT;
352 }
353
354 family->id = idr_alloc_cyclic(&genl_fam_idr, family,
355 start, end + 1, GFP_KERNEL);
356 if (family->id < 0) {
357 err = family->id;
358 goto errout_locked;
359 }
360
361 err = genl_validate_assign_mc_groups(family);
362 if (err)
363 goto errout_remove;
364
365 genl_unlock_all();
366
367 /* send all events */
368 genl_ctrl_event(CTRL_CMD_NEWFAMILY, family, NULL, 0);
369 for (i = 0; i < family->n_mcgrps; i++)
370 genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, family,
371 &family->mcgrps[i], family->mcgrp_offset + i);
372
373 return 0;
374
375errout_remove:
376 idr_remove(&genl_fam_idr, family->id);
377errout_locked:
378 genl_unlock_all();
379 return err;
380}
381EXPORT_SYMBOL(genl_register_family);
382
383/**
384 * genl_unregister_family - unregister generic netlink family
385 * @family: generic netlink family
386 *
387 * Unregisters the specified family.
388 *
389 * Returns 0 on success or a negative error code.
390 */
391int genl_unregister_family(const struct genl_family *family)
392{
393 genl_lock_all();
394
395 if (!genl_family_find_byid(family->id)) {
396 genl_unlock_all();
397 return -ENOENT;
398 }
399
400 genl_unregister_mc_groups(family);
401
402 idr_remove(&genl_fam_idr, family->id);
403
404 up_write(&cb_lock);
405 wait_event(genl_sk_destructing_waitq,
406 atomic_read(&genl_sk_destructing_cnt) == 0);
407 genl_unlock();
408
409 genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 0);
410
411 return 0;
412}
413EXPORT_SYMBOL(genl_unregister_family);
414
415/**
416 * genlmsg_put - Add generic netlink header to netlink message
417 * @skb: socket buffer holding the message
418 * @portid: netlink portid the message is addressed to
419 * @seq: sequence number (usually the one of the sender)
420 * @family: generic netlink family
421 * @flags: netlink message flags
422 * @cmd: generic netlink command
423 *
424 * Returns pointer to user specific header
425 */
426void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
427 const struct genl_family *family, int flags, u8 cmd)
428{
429 struct nlmsghdr *nlh;
430 struct genlmsghdr *hdr;
431
432 nlh = nlmsg_put(skb, portid, seq, family->id, GENL_HDRLEN +
433 family->hdrsize, flags);
434 if (nlh == NULL)
435 return NULL;
436
437 hdr = nlmsg_data(nlh);
438 hdr->cmd = cmd;
439 hdr->version = family->version;
440 hdr->reserved = 0;
441
442 return (char *) hdr + GENL_HDRLEN;
443}
444EXPORT_SYMBOL(genlmsg_put);
445
446static struct genl_dumpit_info *genl_dumpit_info_alloc(void)
447{
448 return kmalloc(sizeof(struct genl_dumpit_info), GFP_KERNEL);
449}
450
451static void genl_dumpit_info_free(const struct genl_dumpit_info *info)
452{
453 kfree(info);
454}
455
456static struct nlattr **
457genl_family_rcv_msg_attrs_parse(const struct genl_family *family,
458 struct nlmsghdr *nlh,
459 struct netlink_ext_ack *extack,
460 const struct genl_ops *ops,
461 int hdrlen,
462 enum genl_validate_flags no_strict_flag)
463{
464 enum netlink_validation validate = ops->validate & no_strict_flag ?
465 NL_VALIDATE_LIBERAL :
466 NL_VALIDATE_STRICT;
467 struct nlattr **attrbuf;
468 int err;
469
470 if (!family->maxattr)
471 return NULL;
472
473 attrbuf = kmalloc_array(family->maxattr + 1,
474 sizeof(struct nlattr *), GFP_KERNEL);
475 if (!attrbuf)
476 return ERR_PTR(-ENOMEM);
477
478 err = __nlmsg_parse(nlh, hdrlen, attrbuf, family->maxattr,
479 family->policy, validate, extack);
480 if (err) {
481 kfree(attrbuf);
482 return ERR_PTR(err);
483 }
484 return attrbuf;
485}
486
487static void genl_family_rcv_msg_attrs_free(struct nlattr **attrbuf)
488{
489 kfree(attrbuf);
490}
491
492struct genl_start_context {
493 const struct genl_family *family;
494 struct nlmsghdr *nlh;
495 struct netlink_ext_ack *extack;
496 const struct genl_ops *ops;
497 int hdrlen;
498};
499
500static int genl_start(struct netlink_callback *cb)
501{
502 struct genl_start_context *ctx = cb->data;
503 const struct genl_ops *ops = ctx->ops;
504 struct genl_dumpit_info *info;
505 struct nlattr **attrs = NULL;
506 int rc = 0;
507
508 if (ops->validate & GENL_DONT_VALIDATE_DUMP)
509 goto no_attrs;
510
511 if (ctx->nlh->nlmsg_len < nlmsg_msg_size(ctx->hdrlen))
512 return -EINVAL;
513
514 attrs = genl_family_rcv_msg_attrs_parse(ctx->family, ctx->nlh, ctx->extack,
515 ops, ctx->hdrlen,
516 GENL_DONT_VALIDATE_DUMP_STRICT);
517 if (IS_ERR(attrs))
518 return PTR_ERR(attrs);
519
520no_attrs:
521 info = genl_dumpit_info_alloc();
522 if (!info) {
523 genl_family_rcv_msg_attrs_free(attrs);
524 return -ENOMEM;
525 }
526 info->family = ctx->family;
527 info->ops = ops;
528 info->attrs = attrs;
529
530 cb->data = info;
531 if (ops->start) {
532 if (!ctx->family->parallel_ops)
533 genl_lock();
534 rc = ops->start(cb);
535 if (!ctx->family->parallel_ops)
536 genl_unlock();
537 }
538
539 if (rc) {
540 genl_family_rcv_msg_attrs_free(info->attrs);
541 genl_dumpit_info_free(info);
542 cb->data = NULL;
543 }
544 return rc;
545}
546
547static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
548{
549 const struct genl_ops *ops = genl_dumpit_info(cb)->ops;
550 int rc;
551
552 genl_lock();
553 rc = ops->dumpit(skb, cb);
554 genl_unlock();
555 return rc;
556}
557
558static int genl_lock_done(struct netlink_callback *cb)
559{
560 const struct genl_dumpit_info *info = genl_dumpit_info(cb);
561 const struct genl_ops *ops = info->ops;
562 int rc = 0;
563
564 if (ops->done) {
565 genl_lock();
566 rc = ops->done(cb);
567 genl_unlock();
568 }
569 genl_family_rcv_msg_attrs_free(info->attrs);
570 genl_dumpit_info_free(info);
571 return rc;
572}
573
574static int genl_parallel_done(struct netlink_callback *cb)
575{
576 const struct genl_dumpit_info *info = genl_dumpit_info(cb);
577 const struct genl_ops *ops = info->ops;
578 int rc = 0;
579
580 if (ops->done)
581 rc = ops->done(cb);
582 genl_family_rcv_msg_attrs_free(info->attrs);
583 genl_dumpit_info_free(info);
584 return rc;
585}
586
587static int genl_family_rcv_msg_dumpit(const struct genl_family *family,
588 struct sk_buff *skb,
589 struct nlmsghdr *nlh,
590 struct netlink_ext_ack *extack,
591 const struct genl_ops *ops,
592 int hdrlen, struct net *net)
593{
594 struct genl_start_context ctx;
595 int err;
596
597 if (!ops->dumpit)
598 return -EOPNOTSUPP;
599
600 ctx.family = family;
601 ctx.nlh = nlh;
602 ctx.extack = extack;
603 ctx.ops = ops;
604 ctx.hdrlen = hdrlen;
605
606 if (!family->parallel_ops) {
607 struct netlink_dump_control c = {
608 .module = family->module,
609 .data = &ctx,
610 .start = genl_start,
611 .dump = genl_lock_dumpit,
612 .done = genl_lock_done,
613 };
614
615 genl_unlock();
616 err = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
617 genl_lock();
618 } else {
619 struct netlink_dump_control c = {
620 .module = family->module,
621 .data = &ctx,
622 .start = genl_start,
623 .dump = ops->dumpit,
624 .done = genl_parallel_done,
625 };
626
627 err = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
628 }
629
630 return err;
631}
632
633static int genl_family_rcv_msg_doit(const struct genl_family *family,
634 struct sk_buff *skb,
635 struct nlmsghdr *nlh,
636 struct netlink_ext_ack *extack,
637 const struct genl_ops *ops,
638 int hdrlen, struct net *net)
639{
640 struct nlattr **attrbuf;
641 struct genl_info info;
642 int err;
643
644 if (!ops->doit)
645 return -EOPNOTSUPP;
646
647 attrbuf = genl_family_rcv_msg_attrs_parse(family, nlh, extack,
648 ops, hdrlen,
649 GENL_DONT_VALIDATE_STRICT);
650 if (IS_ERR(attrbuf))
651 return PTR_ERR(attrbuf);
652
653 info.snd_seq = nlh->nlmsg_seq;
654 info.snd_portid = NETLINK_CB(skb).portid;
655 info.nlhdr = nlh;
656 info.genlhdr = nlmsg_data(nlh);
657 info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
658 info.attrs = attrbuf;
659 info.extack = extack;
660 genl_info_net_set(&info, net);
661 memset(&info.user_ptr, 0, sizeof(info.user_ptr));
662
663 if (family->pre_doit) {
664 err = family->pre_doit(ops, skb, &info);
665 if (err)
666 goto out;
667 }
668
669 err = ops->doit(skb, &info);
670
671 if (family->post_doit)
672 family->post_doit(ops, skb, &info);
673
674out:
675 genl_family_rcv_msg_attrs_free(attrbuf);
676
677 return err;
678}
679
680static int genl_family_rcv_msg(const struct genl_family *family,
681 struct sk_buff *skb,
682 struct nlmsghdr *nlh,
683 struct netlink_ext_ack *extack)
684{
685 const struct genl_ops *ops;
686 struct net *net = sock_net(skb->sk);
687 struct genlmsghdr *hdr = nlmsg_data(nlh);
688 int hdrlen;
689
690 /* this family doesn't exist in this netns */
691 if (!family->netnsok && !net_eq(net, &init_net))
692 return -ENOENT;
693
694 hdrlen = GENL_HDRLEN + family->hdrsize;
695 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
696 return -EINVAL;
697
698 ops = genl_get_cmd(hdr->cmd, family);
699 if (ops == NULL)
700 return -EOPNOTSUPP;
701
702 if ((ops->flags & GENL_ADMIN_PERM) &&
703 !netlink_capable(skb, CAP_NET_ADMIN))
704 return -EPERM;
705
706 if ((ops->flags & GENL_UNS_ADMIN_PERM) &&
707 !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
708 return -EPERM;
709
710 if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP)
711 return genl_family_rcv_msg_dumpit(family, skb, nlh, extack,
712 ops, hdrlen, net);
713 else
714 return genl_family_rcv_msg_doit(family, skb, nlh, extack,
715 ops, hdrlen, net);
716}
717
718static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
719 struct netlink_ext_ack *extack)
720{
721 const struct genl_family *family;
722 int err;
723
724 family = genl_family_find_byid(nlh->nlmsg_type);
725 if (family == NULL)
726 return -ENOENT;
727
728 if (!family->parallel_ops)
729 genl_lock();
730
731 err = genl_family_rcv_msg(family, skb, nlh, extack);
732
733 if (!family->parallel_ops)
734 genl_unlock();
735
736 return err;
737}
738
739static void genl_rcv(struct sk_buff *skb)
740{
741 down_read(&cb_lock);
742 netlink_rcv_skb(skb, &genl_rcv_msg);
743 up_read(&cb_lock);
744}
745
746/**************************************************************************
747 * Controller
748 **************************************************************************/
749
750static struct genl_family genl_ctrl;
751
752static int ctrl_fill_info(const struct genl_family *family, u32 portid, u32 seq,
753 u32 flags, struct sk_buff *skb, u8 cmd)
754{
755 void *hdr;
756
757 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
758 if (hdr == NULL)
759 return -1;
760
761 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
762 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) ||
763 nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) ||
764 nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) ||
765 nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr))
766 goto nla_put_failure;
767
768 if (family->n_ops) {
769 struct nlattr *nla_ops;
770 int i;
771
772 nla_ops = nla_nest_start_noflag(skb, CTRL_ATTR_OPS);
773 if (nla_ops == NULL)
774 goto nla_put_failure;
775
776 for (i = 0; i < family->n_ops; i++) {
777 struct nlattr *nest;
778 const struct genl_ops *ops = &family->ops[i];
779 u32 op_flags = ops->flags;
780
781 if (ops->dumpit)
782 op_flags |= GENL_CMD_CAP_DUMP;
783 if (ops->doit)
784 op_flags |= GENL_CMD_CAP_DO;
785 if (family->policy)
786 op_flags |= GENL_CMD_CAP_HASPOL;
787
788 nest = nla_nest_start_noflag(skb, i + 1);
789 if (nest == NULL)
790 goto nla_put_failure;
791
792 if (nla_put_u32(skb, CTRL_ATTR_OP_ID, ops->cmd) ||
793 nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, op_flags))
794 goto nla_put_failure;
795
796 nla_nest_end(skb, nest);
797 }
798
799 nla_nest_end(skb, nla_ops);
800 }
801
802 if (family->n_mcgrps) {
803 struct nlattr *nla_grps;
804 int i;
805
806 nla_grps = nla_nest_start_noflag(skb, CTRL_ATTR_MCAST_GROUPS);
807 if (nla_grps == NULL)
808 goto nla_put_failure;
809
810 for (i = 0; i < family->n_mcgrps; i++) {
811 struct nlattr *nest;
812 const struct genl_multicast_group *grp;
813
814 grp = &family->mcgrps[i];
815
816 nest = nla_nest_start_noflag(skb, i + 1);
817 if (nest == NULL)
818 goto nla_put_failure;
819
820 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID,
821 family->mcgrp_offset + i) ||
822 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
823 grp->name))
824 goto nla_put_failure;
825
826 nla_nest_end(skb, nest);
827 }
828 nla_nest_end(skb, nla_grps);
829 }
830
831 genlmsg_end(skb, hdr);
832 return 0;
833
834nla_put_failure:
835 genlmsg_cancel(skb, hdr);
836 return -EMSGSIZE;
837}
838
839static int ctrl_fill_mcgrp_info(const struct genl_family *family,
840 const struct genl_multicast_group *grp,
841 int grp_id, u32 portid, u32 seq, u32 flags,
842 struct sk_buff *skb, u8 cmd)
843{
844 void *hdr;
845 struct nlattr *nla_grps;
846 struct nlattr *nest;
847
848 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
849 if (hdr == NULL)
850 return -1;
851
852 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
853 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id))
854 goto nla_put_failure;
855
856 nla_grps = nla_nest_start_noflag(skb, CTRL_ATTR_MCAST_GROUPS);
857 if (nla_grps == NULL)
858 goto nla_put_failure;
859
860 nest = nla_nest_start_noflag(skb, 1);
861 if (nest == NULL)
862 goto nla_put_failure;
863
864 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp_id) ||
865 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
866 grp->name))
867 goto nla_put_failure;
868
869 nla_nest_end(skb, nest);
870 nla_nest_end(skb, nla_grps);
871
872 genlmsg_end(skb, hdr);
873 return 0;
874
875nla_put_failure:
876 genlmsg_cancel(skb, hdr);
877 return -EMSGSIZE;
878}
879
880static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
881{
882 int n = 0;
883 struct genl_family *rt;
884 struct net *net = sock_net(skb->sk);
885 int fams_to_skip = cb->args[0];
886 unsigned int id;
887
888 idr_for_each_entry(&genl_fam_idr, rt, id) {
889 if (!rt->netnsok && !net_eq(net, &init_net))
890 continue;
891
892 if (n++ < fams_to_skip)
893 continue;
894
895 if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid,
896 cb->nlh->nlmsg_seq, NLM_F_MULTI,
897 skb, CTRL_CMD_NEWFAMILY) < 0) {
898 n--;
899 break;
900 }
901 }
902
903 cb->args[0] = n;
904 return skb->len;
905}
906
907static struct sk_buff *ctrl_build_family_msg(const struct genl_family *family,
908 u32 portid, int seq, u8 cmd)
909{
910 struct sk_buff *skb;
911 int err;
912
913 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
914 if (skb == NULL)
915 return ERR_PTR(-ENOBUFS);
916
917 err = ctrl_fill_info(family, portid, seq, 0, skb, cmd);
918 if (err < 0) {
919 nlmsg_free(skb);
920 return ERR_PTR(err);
921 }
922
923 return skb;
924}
925
926static struct sk_buff *
927ctrl_build_mcgrp_msg(const struct genl_family *family,
928 const struct genl_multicast_group *grp,
929 int grp_id, u32 portid, int seq, u8 cmd)
930{
931 struct sk_buff *skb;
932 int err;
933
934 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
935 if (skb == NULL)
936 return ERR_PTR(-ENOBUFS);
937
938 err = ctrl_fill_mcgrp_info(family, grp, grp_id, portid,
939 seq, 0, skb, cmd);
940 if (err < 0) {
941 nlmsg_free(skb);
942 return ERR_PTR(err);
943 }
944
945 return skb;
946}
947
948static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
949 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 },
950 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
951 .len = GENL_NAMSIZ - 1 },
952};
953
954static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
955{
956 struct sk_buff *msg;
957 const struct genl_family *res = NULL;
958 int err = -EINVAL;
959
960 if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
961 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
962 res = genl_family_find_byid(id);
963 err = -ENOENT;
964 }
965
966 if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
967 char *name;
968
969 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
970 res = genl_family_find_byname(name);
971#ifdef CONFIG_MODULES
972 if (res == NULL) {
973 genl_unlock();
974 up_read(&cb_lock);
975 request_module("net-pf-%d-proto-%d-family-%s",
976 PF_NETLINK, NETLINK_GENERIC, name);
977 down_read(&cb_lock);
978 genl_lock();
979 res = genl_family_find_byname(name);
980 }
981#endif
982 err = -ENOENT;
983 }
984
985 if (res == NULL)
986 return err;
987
988 if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) {
989 /* family doesn't exist here */
990 return -ENOENT;
991 }
992
993 msg = ctrl_build_family_msg(res, info->snd_portid, info->snd_seq,
994 CTRL_CMD_NEWFAMILY);
995 if (IS_ERR(msg))
996 return PTR_ERR(msg);
997
998 return genlmsg_reply(msg, info);
999}
1000
1001static int genl_ctrl_event(int event, const struct genl_family *family,
1002 const struct genl_multicast_group *grp,
1003 int grp_id)
1004{
1005 struct sk_buff *msg;
1006
1007 /* genl is still initialising */
1008 if (!init_net.genl_sock)
1009 return 0;
1010
1011 switch (event) {
1012 case CTRL_CMD_NEWFAMILY:
1013 case CTRL_CMD_DELFAMILY:
1014 WARN_ON(grp);
1015 msg = ctrl_build_family_msg(family, 0, 0, event);
1016 break;
1017 case CTRL_CMD_NEWMCAST_GRP:
1018 case CTRL_CMD_DELMCAST_GRP:
1019 BUG_ON(!grp);
1020 msg = ctrl_build_mcgrp_msg(family, grp, grp_id, 0, 0, event);
1021 break;
1022 default:
1023 return -EINVAL;
1024 }
1025
1026 if (IS_ERR(msg))
1027 return PTR_ERR(msg);
1028
1029 if (!family->netnsok) {
1030 genlmsg_multicast_netns(&genl_ctrl, &init_net, msg, 0,
1031 0, GFP_KERNEL);
1032 } else {
1033 rcu_read_lock();
1034 genlmsg_multicast_allns(&genl_ctrl, msg, 0,
1035 0, GFP_ATOMIC);
1036 rcu_read_unlock();
1037 }
1038
1039 return 0;
1040}
1041
1042static int ctrl_dumppolicy(struct sk_buff *skb, struct netlink_callback *cb)
1043{
1044 const struct genl_family *rt;
1045 unsigned int fam_id = cb->args[0];
1046 int err;
1047
1048 if (!fam_id) {
1049 struct nlattr *tb[CTRL_ATTR_MAX + 1];
1050
1051 err = genlmsg_parse(cb->nlh, &genl_ctrl, tb,
1052 genl_ctrl.maxattr,
1053 genl_ctrl.policy, cb->extack);
1054 if (err)
1055 return err;
1056
1057 if (!tb[CTRL_ATTR_FAMILY_ID] && !tb[CTRL_ATTR_FAMILY_NAME])
1058 return -EINVAL;
1059
1060 if (tb[CTRL_ATTR_FAMILY_ID]) {
1061 fam_id = nla_get_u16(tb[CTRL_ATTR_FAMILY_ID]);
1062 } else {
1063 rt = genl_family_find_byname(
1064 nla_data(tb[CTRL_ATTR_FAMILY_NAME]));
1065 if (!rt)
1066 return -ENOENT;
1067 fam_id = rt->id;
1068 }
1069 }
1070
1071 rt = genl_family_find_byid(fam_id);
1072 if (!rt)
1073 return -ENOENT;
1074
1075 if (!rt->policy)
1076 return -ENODATA;
1077
1078 err = netlink_policy_dump_start(rt->policy, rt->maxattr, &cb->args[1]);
1079 if (err)
1080 return err;
1081
1082 while (netlink_policy_dump_loop(cb->args[1])) {
1083 void *hdr;
1084 struct nlattr *nest;
1085
1086 hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid,
1087 cb->nlh->nlmsg_seq, &genl_ctrl,
1088 NLM_F_MULTI, CTRL_CMD_GETPOLICY);
1089 if (!hdr)
1090 goto nla_put_failure;
1091
1092 if (nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, rt->id))
1093 goto nla_put_failure;
1094
1095 nest = nla_nest_start(skb, CTRL_ATTR_POLICY);
1096 if (!nest)
1097 goto nla_put_failure;
1098
1099 if (netlink_policy_dump_write(skb, cb->args[1]))
1100 goto nla_put_failure;
1101
1102 nla_nest_end(skb, nest);
1103
1104 genlmsg_end(skb, hdr);
1105 continue;
1106
1107nla_put_failure:
1108 genlmsg_cancel(skb, hdr);
1109 break;
1110 }
1111
1112 cb->args[0] = fam_id;
1113 return skb->len;
1114}
1115
1116static int ctrl_dumppolicy_done(struct netlink_callback *cb)
1117{
1118 netlink_policy_dump_free(cb->args[1]);
1119 return 0;
1120}
1121
1122static const struct genl_ops genl_ctrl_ops[] = {
1123 {
1124 .cmd = CTRL_CMD_GETFAMILY,
1125 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1126 .doit = ctrl_getfamily,
1127 .dumpit = ctrl_dumpfamily,
1128 },
1129 {
1130 .cmd = CTRL_CMD_GETPOLICY,
1131 .dumpit = ctrl_dumppolicy,
1132 .done = ctrl_dumppolicy_done,
1133 },
1134};
1135
1136static const struct genl_multicast_group genl_ctrl_groups[] = {
1137 { .name = "notify", },
1138};
1139
1140static struct genl_family genl_ctrl __ro_after_init = {
1141 .module = THIS_MODULE,
1142 .ops = genl_ctrl_ops,
1143 .n_ops = ARRAY_SIZE(genl_ctrl_ops),
1144 .mcgrps = genl_ctrl_groups,
1145 .n_mcgrps = ARRAY_SIZE(genl_ctrl_groups),
1146 .id = GENL_ID_CTRL,
1147 .name = "nlctrl",
1148 .version = 0x2,
1149 .maxattr = CTRL_ATTR_MAX,
1150 .policy = ctrl_policy,
1151 .netnsok = true,
1152};
1153
1154static int __net_init genl_pernet_init(struct net *net)
1155{
1156 struct netlink_kernel_cfg cfg = {
1157 .input = genl_rcv,
1158 .flags = NL_CFG_F_NONROOT_RECV,
1159 };
1160
1161 /* we'll bump the group number right afterwards */
1162 net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg);
1163
1164 if (!net->genl_sock && net_eq(net, &init_net))
1165 panic("GENL: Cannot initialize generic netlink\n");
1166
1167 if (!net->genl_sock)
1168 return -ENOMEM;
1169
1170 return 0;
1171}
1172
1173static void __net_exit genl_pernet_exit(struct net *net)
1174{
1175 netlink_kernel_release(net->genl_sock);
1176 net->genl_sock = NULL;
1177}
1178
1179static struct pernet_operations genl_pernet_ops = {
1180 .init = genl_pernet_init,
1181 .exit = genl_pernet_exit,
1182};
1183
1184static int __init genl_init(void)
1185{
1186 int err;
1187
1188 err = genl_register_family(&genl_ctrl);
1189 if (err < 0)
1190 goto problem;
1191
1192 err = register_pernet_subsys(&genl_pernet_ops);
1193 if (err)
1194 goto problem;
1195
1196 return 0;
1197
1198problem:
1199 panic("GENL: Cannot register controller: %d\n", err);
1200}
1201
1202core_initcall(genl_init);
1203
1204static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
1205 gfp_t flags)
1206{
1207 struct sk_buff *tmp;
1208 struct net *net, *prev = NULL;
1209 bool delivered = false;
1210 int err;
1211
1212 for_each_net_rcu(net) {
1213 if (prev) {
1214 tmp = skb_clone(skb, flags);
1215 if (!tmp) {
1216 err = -ENOMEM;
1217 goto error;
1218 }
1219 err = nlmsg_multicast(prev->genl_sock, tmp,
1220 portid, group, flags);
1221 if (!err)
1222 delivered = true;
1223 else if (err != -ESRCH)
1224 goto error;
1225 }
1226
1227 prev = net;
1228 }
1229
1230 err = nlmsg_multicast(prev->genl_sock, skb, portid, group, flags);
1231 if (!err)
1232 delivered = true;
1233 else if (err != -ESRCH)
1234 return err;
1235 return delivered ? 0 : -ESRCH;
1236 error:
1237 kfree_skb(skb);
1238 return err;
1239}
1240
1241int genlmsg_multicast_allns(const struct genl_family *family,
1242 struct sk_buff *skb, u32 portid,
1243 unsigned int group, gfp_t flags)
1244{
1245 if (WARN_ON_ONCE(group >= family->n_mcgrps))
1246 return -EINVAL;
1247 group = family->mcgrp_offset + group;
1248 return genlmsg_mcast(skb, portid, group, flags);
1249}
1250EXPORT_SYMBOL(genlmsg_multicast_allns);
1251
1252void genl_notify(const struct genl_family *family, struct sk_buff *skb,
1253 struct genl_info *info, u32 group, gfp_t flags)
1254{
1255 struct net *net = genl_info_net(info);
1256 struct sock *sk = net->genl_sock;
1257 int report = 0;
1258
1259 if (info->nlhdr)
1260 report = nlmsg_report(info->nlhdr);
1261
1262 if (WARN_ON_ONCE(group >= family->n_mcgrps))
1263 return;
1264 group = family->mcgrp_offset + group;
1265 nlmsg_notify(sk, skb, info->snd_portid, group, report, flags);
1266}
1267EXPORT_SYMBOL(genl_notify);