Loading...
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/*
2 * NETLINK Generic Netlink Family
3 *
4 * Authors: Jamal Hadi Salim
5 * Thomas Graf <tgraf@suug.ch>
6 * Johannes Berg <johannes@sipsolutions.net>
7 */
8
9#include <linux/module.h>
10#include <linux/kernel.h>
11#include <linux/slab.h>
12#include <linux/errno.h>
13#include <linux/types.h>
14#include <linux/socket.h>
15#include <linux/string.h>
16#include <linux/skbuff.h>
17#include <linux/mutex.h>
18#include <linux/bitmap.h>
19#include <net/sock.h>
20#include <net/genetlink.h>
21
22static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */
23
24void genl_lock(void)
25{
26 mutex_lock(&genl_mutex);
27}
28EXPORT_SYMBOL(genl_lock);
29
30void genl_unlock(void)
31{
32 mutex_unlock(&genl_mutex);
33}
34EXPORT_SYMBOL(genl_unlock);
35
36#define GENL_FAM_TAB_SIZE 16
37#define GENL_FAM_TAB_MASK (GENL_FAM_TAB_SIZE - 1)
38
39static struct list_head family_ht[GENL_FAM_TAB_SIZE];
40/*
41 * Bitmap of multicast groups that are currently in use.
42 *
43 * To avoid an allocation at boot of just one unsigned long,
44 * declare it global instead.
45 * Bit 0 is marked as already used since group 0 is invalid.
46 */
47static unsigned long mc_group_start = 0x1;
48static unsigned long *mc_groups = &mc_group_start;
49static unsigned long mc_groups_longs = 1;
50
51static int genl_ctrl_event(int event, void *data);
52
53static inline unsigned int genl_family_hash(unsigned int id)
54{
55 return id & GENL_FAM_TAB_MASK;
56}
57
58static inline struct list_head *genl_family_chain(unsigned int id)
59{
60 return &family_ht[genl_family_hash(id)];
61}
62
63static struct genl_family *genl_family_find_byid(unsigned int id)
64{
65 struct genl_family *f;
66
67 list_for_each_entry(f, genl_family_chain(id), family_list)
68 if (f->id == id)
69 return f;
70
71 return NULL;
72}
73
74static struct genl_family *genl_family_find_byname(char *name)
75{
76 struct genl_family *f;
77 int i;
78
79 for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
80 list_for_each_entry(f, genl_family_chain(i), family_list)
81 if (strcmp(f->name, name) == 0)
82 return f;
83
84 return NULL;
85}
86
87static struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family)
88{
89 struct genl_ops *ops;
90
91 list_for_each_entry(ops, &family->ops_list, ops_list)
92 if (ops->cmd == cmd)
93 return ops;
94
95 return NULL;
96}
97
98/* Of course we are going to have problems once we hit
99 * 2^16 alive types, but that can only happen by year 2K
100*/
101static inline u16 genl_generate_id(void)
102{
103 static u16 id_gen_idx = GENL_MIN_ID;
104 int i;
105
106 for (i = 0; i <= GENL_MAX_ID - GENL_MIN_ID; i++) {
107 if (!genl_family_find_byid(id_gen_idx))
108 return id_gen_idx;
109 if (++id_gen_idx > GENL_MAX_ID)
110 id_gen_idx = GENL_MIN_ID;
111 }
112
113 return 0;
114}
115
116static struct genl_multicast_group notify_grp;
117
118/**
119 * genl_register_mc_group - register a multicast group
120 *
121 * Registers the specified multicast group and notifies userspace
122 * about the new group.
123 *
124 * Returns 0 on success or a negative error code.
125 *
126 * @family: The generic netlink family the group shall be registered for.
127 * @grp: The group to register, must have a name.
128 */
129int genl_register_mc_group(struct genl_family *family,
130 struct genl_multicast_group *grp)
131{
132 int id;
133 unsigned long *new_groups;
134 int err = 0;
135
136 BUG_ON(grp->name[0] == '\0');
137
138 genl_lock();
139
140 /* special-case our own group */
141 if (grp == ¬ify_grp)
142 id = GENL_ID_CTRL;
143 else
144 id = find_first_zero_bit(mc_groups,
145 mc_groups_longs * BITS_PER_LONG);
146
147
148 if (id >= mc_groups_longs * BITS_PER_LONG) {
149 size_t nlen = (mc_groups_longs + 1) * sizeof(unsigned long);
150
151 if (mc_groups == &mc_group_start) {
152 new_groups = kzalloc(nlen, GFP_KERNEL);
153 if (!new_groups) {
154 err = -ENOMEM;
155 goto out;
156 }
157 mc_groups = new_groups;
158 *mc_groups = mc_group_start;
159 } else {
160 new_groups = krealloc(mc_groups, nlen, GFP_KERNEL);
161 if (!new_groups) {
162 err = -ENOMEM;
163 goto out;
164 }
165 mc_groups = new_groups;
166 mc_groups[mc_groups_longs] = 0;
167 }
168 mc_groups_longs++;
169 }
170
171 if (family->netnsok) {
172 struct net *net;
173
174 netlink_table_grab();
175 rcu_read_lock();
176 for_each_net_rcu(net) {
177 err = __netlink_change_ngroups(net->genl_sock,
178 mc_groups_longs * BITS_PER_LONG);
179 if (err) {
180 /*
181 * No need to roll back, can only fail if
182 * memory allocation fails and then the
183 * number of _possible_ groups has been
184 * increased on some sockets which is ok.
185 */
186 rcu_read_unlock();
187 netlink_table_ungrab();
188 goto out;
189 }
190 }
191 rcu_read_unlock();
192 netlink_table_ungrab();
193 } else {
194 err = netlink_change_ngroups(init_net.genl_sock,
195 mc_groups_longs * BITS_PER_LONG);
196 if (err)
197 goto out;
198 }
199
200 grp->id = id;
201 set_bit(id, mc_groups);
202 list_add_tail(&grp->list, &family->mcast_groups);
203 grp->family = family;
204
205 genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, grp);
206 out:
207 genl_unlock();
208 return err;
209}
210EXPORT_SYMBOL(genl_register_mc_group);
211
212static void __genl_unregister_mc_group(struct genl_family *family,
213 struct genl_multicast_group *grp)
214{
215 struct net *net;
216 BUG_ON(grp->family != family);
217
218 netlink_table_grab();
219 rcu_read_lock();
220 for_each_net_rcu(net)
221 __netlink_clear_multicast_users(net->genl_sock, grp->id);
222 rcu_read_unlock();
223 netlink_table_ungrab();
224
225 clear_bit(grp->id, mc_groups);
226 list_del(&grp->list);
227 genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, grp);
228 grp->id = 0;
229 grp->family = NULL;
230}
231
232/**
233 * genl_unregister_mc_group - unregister a multicast group
234 *
235 * Unregisters the specified multicast group and notifies userspace
236 * about it. All current listeners on the group are removed.
237 *
238 * Note: It is not necessary to unregister all multicast groups before
239 * unregistering the family, unregistering the family will cause
240 * all assigned multicast groups to be unregistered automatically.
241 *
242 * @family: Generic netlink family the group belongs to.
243 * @grp: The group to unregister, must have been registered successfully
244 * previously.
245 */
246void genl_unregister_mc_group(struct genl_family *family,
247 struct genl_multicast_group *grp)
248{
249 genl_lock();
250 __genl_unregister_mc_group(family, grp);
251 genl_unlock();
252}
253EXPORT_SYMBOL(genl_unregister_mc_group);
254
255static void genl_unregister_mc_groups(struct genl_family *family)
256{
257 struct genl_multicast_group *grp, *tmp;
258
259 list_for_each_entry_safe(grp, tmp, &family->mcast_groups, list)
260 __genl_unregister_mc_group(family, grp);
261}
262
263/**
264 * genl_register_ops - register generic netlink operations
265 * @family: generic netlink family
266 * @ops: operations to be registered
267 *
268 * Registers the specified operations and assigns them to the specified
269 * family. Either a doit or dumpit callback must be specified or the
270 * operation will fail. Only one operation structure per command
271 * identifier may be registered.
272 *
273 * See include/net/genetlink.h for more documenation on the operations
274 * structure.
275 *
276 * Returns 0 on success or a negative error code.
277 */
278int genl_register_ops(struct genl_family *family, struct genl_ops *ops)
279{
280 int err = -EINVAL;
281
282 if (ops->dumpit == NULL && ops->doit == NULL)
283 goto errout;
284
285 if (genl_get_cmd(ops->cmd, family)) {
286 err = -EEXIST;
287 goto errout;
288 }
289
290 if (ops->dumpit)
291 ops->flags |= GENL_CMD_CAP_DUMP;
292 if (ops->doit)
293 ops->flags |= GENL_CMD_CAP_DO;
294 if (ops->policy)
295 ops->flags |= GENL_CMD_CAP_HASPOL;
296
297 genl_lock();
298 list_add_tail(&ops->ops_list, &family->ops_list);
299 genl_unlock();
300
301 genl_ctrl_event(CTRL_CMD_NEWOPS, ops);
302 err = 0;
303errout:
304 return err;
305}
306EXPORT_SYMBOL(genl_register_ops);
307
308/**
309 * genl_unregister_ops - unregister generic netlink operations
310 * @family: generic netlink family
311 * @ops: operations to be unregistered
312 *
313 * Unregisters the specified operations and unassigns them from the
314 * specified family. The operation blocks until the current message
315 * processing has finished and doesn't start again until the
316 * unregister process has finished.
317 *
318 * Note: It is not necessary to unregister all operations before
319 * unregistering the family, unregistering the family will cause
320 * all assigned operations to be unregistered automatically.
321 *
322 * Returns 0 on success or a negative error code.
323 */
324int genl_unregister_ops(struct genl_family *family, struct genl_ops *ops)
325{
326 struct genl_ops *rc;
327
328 genl_lock();
329 list_for_each_entry(rc, &family->ops_list, ops_list) {
330 if (rc == ops) {
331 list_del(&ops->ops_list);
332 genl_unlock();
333 genl_ctrl_event(CTRL_CMD_DELOPS, ops);
334 return 0;
335 }
336 }
337 genl_unlock();
338
339 return -ENOENT;
340}
341EXPORT_SYMBOL(genl_unregister_ops);
342
343/**
344 * genl_register_family - register a generic netlink family
345 * @family: generic netlink family
346 *
347 * Registers the specified family after validating it first. Only one
348 * family may be registered with the same family name or identifier.
349 * The family id may equal GENL_ID_GENERATE causing an unique id to
350 * be automatically generated and assigned.
351 *
352 * Return 0 on success or a negative error code.
353 */
354int genl_register_family(struct genl_family *family)
355{
356 int err = -EINVAL;
357
358 if (family->id && family->id < GENL_MIN_ID)
359 goto errout;
360
361 if (family->id > GENL_MAX_ID)
362 goto errout;
363
364 INIT_LIST_HEAD(&family->ops_list);
365 INIT_LIST_HEAD(&family->mcast_groups);
366
367 genl_lock();
368
369 if (genl_family_find_byname(family->name)) {
370 err = -EEXIST;
371 goto errout_locked;
372 }
373
374 if (family->id == GENL_ID_GENERATE) {
375 u16 newid = genl_generate_id();
376
377 if (!newid) {
378 err = -ENOMEM;
379 goto errout_locked;
380 }
381
382 family->id = newid;
383 } else if (genl_family_find_byid(family->id)) {
384 err = -EEXIST;
385 goto errout_locked;
386 }
387
388 if (family->maxattr) {
389 family->attrbuf = kmalloc((family->maxattr+1) *
390 sizeof(struct nlattr *), GFP_KERNEL);
391 if (family->attrbuf == NULL) {
392 err = -ENOMEM;
393 goto errout_locked;
394 }
395 } else
396 family->attrbuf = NULL;
397
398 list_add_tail(&family->family_list, genl_family_chain(family->id));
399 genl_unlock();
400
401 genl_ctrl_event(CTRL_CMD_NEWFAMILY, family);
402
403 return 0;
404
405errout_locked:
406 genl_unlock();
407errout:
408 return err;
409}
410EXPORT_SYMBOL(genl_register_family);
411
412/**
413 * genl_register_family_with_ops - register a generic netlink family
414 * @family: generic netlink family
415 * @ops: operations to be registered
416 * @n_ops: number of elements to register
417 *
418 * Registers the specified family and operations from the specified table.
419 * Only one family may be registered with the same family name or identifier.
420 *
421 * The family id may equal GENL_ID_GENERATE causing an unique id to
422 * be automatically generated and assigned.
423 *
424 * Either a doit or dumpit callback must be specified for every registered
425 * operation or the function will fail. Only one operation structure per
426 * command identifier may be registered.
427 *
428 * See include/net/genetlink.h for more documenation on the operations
429 * structure.
430 *
431 * This is equivalent to calling genl_register_family() followed by
432 * genl_register_ops() for every operation entry in the table taking
433 * care to unregister the family on error path.
434 *
435 * Return 0 on success or a negative error code.
436 */
437int genl_register_family_with_ops(struct genl_family *family,
438 struct genl_ops *ops, size_t n_ops)
439{
440 int err, i;
441
442 err = genl_register_family(family);
443 if (err)
444 return err;
445
446 for (i = 0; i < n_ops; ++i, ++ops) {
447 err = genl_register_ops(family, ops);
448 if (err)
449 goto err_out;
450 }
451 return 0;
452err_out:
453 genl_unregister_family(family);
454 return err;
455}
456EXPORT_SYMBOL(genl_register_family_with_ops);
457
458/**
459 * genl_unregister_family - unregister generic netlink family
460 * @family: generic netlink family
461 *
462 * Unregisters the specified family.
463 *
464 * Returns 0 on success or a negative error code.
465 */
466int genl_unregister_family(struct genl_family *family)
467{
468 struct genl_family *rc;
469
470 genl_lock();
471
472 genl_unregister_mc_groups(family);
473
474 list_for_each_entry(rc, genl_family_chain(family->id), family_list) {
475 if (family->id != rc->id || strcmp(rc->name, family->name))
476 continue;
477
478 list_del(&rc->family_list);
479 INIT_LIST_HEAD(&family->ops_list);
480 genl_unlock();
481
482 kfree(family->attrbuf);
483 genl_ctrl_event(CTRL_CMD_DELFAMILY, family);
484 return 0;
485 }
486
487 genl_unlock();
488
489 return -ENOENT;
490}
491EXPORT_SYMBOL(genl_unregister_family);
492
493static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
494{
495 struct genl_ops *ops;
496 struct genl_family *family;
497 struct net *net = sock_net(skb->sk);
498 struct genl_info info;
499 struct genlmsghdr *hdr = nlmsg_data(nlh);
500 int hdrlen, err;
501
502 family = genl_family_find_byid(nlh->nlmsg_type);
503 if (family == NULL)
504 return -ENOENT;
505
506 /* this family doesn't exist in this netns */
507 if (!family->netnsok && !net_eq(net, &init_net))
508 return -ENOENT;
509
510 hdrlen = GENL_HDRLEN + family->hdrsize;
511 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
512 return -EINVAL;
513
514 ops = genl_get_cmd(hdr->cmd, family);
515 if (ops == NULL)
516 return -EOPNOTSUPP;
517
518 if ((ops->flags & GENL_ADMIN_PERM) &&
519 security_netlink_recv(skb, CAP_NET_ADMIN))
520 return -EPERM;
521
522 if (nlh->nlmsg_flags & NLM_F_DUMP) {
523 if (ops->dumpit == NULL)
524 return -EOPNOTSUPP;
525
526 genl_unlock();
527 err = netlink_dump_start(net->genl_sock, skb, nlh,
528 ops->dumpit, ops->done, 0);
529 genl_lock();
530 return err;
531 }
532
533 if (ops->doit == NULL)
534 return -EOPNOTSUPP;
535
536 if (family->attrbuf) {
537 err = nlmsg_parse(nlh, hdrlen, family->attrbuf, family->maxattr,
538 ops->policy);
539 if (err < 0)
540 return err;
541 }
542
543 info.snd_seq = nlh->nlmsg_seq;
544 info.snd_pid = NETLINK_CB(skb).pid;
545 info.nlhdr = nlh;
546 info.genlhdr = nlmsg_data(nlh);
547 info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
548 info.attrs = family->attrbuf;
549 genl_info_net_set(&info, net);
550 memset(&info.user_ptr, 0, sizeof(info.user_ptr));
551
552 if (family->pre_doit) {
553 err = family->pre_doit(ops, skb, &info);
554 if (err)
555 return err;
556 }
557
558 err = ops->doit(skb, &info);
559
560 if (family->post_doit)
561 family->post_doit(ops, skb, &info);
562
563 return err;
564}
565
566static void genl_rcv(struct sk_buff *skb)
567{
568 genl_lock();
569 netlink_rcv_skb(skb, &genl_rcv_msg);
570 genl_unlock();
571}
572
573/**************************************************************************
574 * Controller
575 **************************************************************************/
576
577static struct genl_family genl_ctrl = {
578 .id = GENL_ID_CTRL,
579 .name = "nlctrl",
580 .version = 0x2,
581 .maxattr = CTRL_ATTR_MAX,
582 .netnsok = true,
583};
584
585static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
586 u32 flags, struct sk_buff *skb, u8 cmd)
587{
588 void *hdr;
589
590 hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
591 if (hdr == NULL)
592 return -1;
593
594 NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, family->name);
595 NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, family->id);
596 NLA_PUT_U32(skb, CTRL_ATTR_VERSION, family->version);
597 NLA_PUT_U32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize);
598 NLA_PUT_U32(skb, CTRL_ATTR_MAXATTR, family->maxattr);
599
600 if (!list_empty(&family->ops_list)) {
601 struct nlattr *nla_ops;
602 struct genl_ops *ops;
603 int idx = 1;
604
605 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
606 if (nla_ops == NULL)
607 goto nla_put_failure;
608
609 list_for_each_entry(ops, &family->ops_list, ops_list) {
610 struct nlattr *nest;
611
612 nest = nla_nest_start(skb, idx++);
613 if (nest == NULL)
614 goto nla_put_failure;
615
616 NLA_PUT_U32(skb, CTRL_ATTR_OP_ID, ops->cmd);
617 NLA_PUT_U32(skb, CTRL_ATTR_OP_FLAGS, ops->flags);
618
619 nla_nest_end(skb, nest);
620 }
621
622 nla_nest_end(skb, nla_ops);
623 }
624
625 if (!list_empty(&family->mcast_groups)) {
626 struct genl_multicast_group *grp;
627 struct nlattr *nla_grps;
628 int idx = 1;
629
630 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
631 if (nla_grps == NULL)
632 goto nla_put_failure;
633
634 list_for_each_entry(grp, &family->mcast_groups, list) {
635 struct nlattr *nest;
636
637 nest = nla_nest_start(skb, idx++);
638 if (nest == NULL)
639 goto nla_put_failure;
640
641 NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
642 NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
643 grp->name);
644
645 nla_nest_end(skb, nest);
646 }
647 nla_nest_end(skb, nla_grps);
648 }
649
650 return genlmsg_end(skb, hdr);
651
652nla_put_failure:
653 genlmsg_cancel(skb, hdr);
654 return -EMSGSIZE;
655}
656
657static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 pid,
658 u32 seq, u32 flags, struct sk_buff *skb,
659 u8 cmd)
660{
661 void *hdr;
662 struct nlattr *nla_grps;
663 struct nlattr *nest;
664
665 hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
666 if (hdr == NULL)
667 return -1;
668
669 NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, grp->family->name);
670 NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, grp->family->id);
671
672 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
673 if (nla_grps == NULL)
674 goto nla_put_failure;
675
676 nest = nla_nest_start(skb, 1);
677 if (nest == NULL)
678 goto nla_put_failure;
679
680 NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
681 NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
682 grp->name);
683
684 nla_nest_end(skb, nest);
685 nla_nest_end(skb, nla_grps);
686
687 return genlmsg_end(skb, hdr);
688
689nla_put_failure:
690 genlmsg_cancel(skb, hdr);
691 return -EMSGSIZE;
692}
693
694static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
695{
696
697 int i, n = 0;
698 struct genl_family *rt;
699 struct net *net = sock_net(skb->sk);
700 int chains_to_skip = cb->args[0];
701 int fams_to_skip = cb->args[1];
702
703 for (i = chains_to_skip; i < GENL_FAM_TAB_SIZE; i++) {
704 n = 0;
705 list_for_each_entry(rt, genl_family_chain(i), family_list) {
706 if (!rt->netnsok && !net_eq(net, &init_net))
707 continue;
708 if (++n < fams_to_skip)
709 continue;
710 if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).pid,
711 cb->nlh->nlmsg_seq, NLM_F_MULTI,
712 skb, CTRL_CMD_NEWFAMILY) < 0)
713 goto errout;
714 }
715
716 fams_to_skip = 0;
717 }
718
719errout:
720 cb->args[0] = i;
721 cb->args[1] = n;
722
723 return skb->len;
724}
725
726static struct sk_buff *ctrl_build_family_msg(struct genl_family *family,
727 u32 pid, int seq, u8 cmd)
728{
729 struct sk_buff *skb;
730 int err;
731
732 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
733 if (skb == NULL)
734 return ERR_PTR(-ENOBUFS);
735
736 err = ctrl_fill_info(family, pid, seq, 0, skb, cmd);
737 if (err < 0) {
738 nlmsg_free(skb);
739 return ERR_PTR(err);
740 }
741
742 return skb;
743}
744
745static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_multicast_group *grp,
746 u32 pid, int seq, u8 cmd)
747{
748 struct sk_buff *skb;
749 int err;
750
751 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
752 if (skb == NULL)
753 return ERR_PTR(-ENOBUFS);
754
755 err = ctrl_fill_mcgrp_info(grp, pid, seq, 0, skb, cmd);
756 if (err < 0) {
757 nlmsg_free(skb);
758 return ERR_PTR(err);
759 }
760
761 return skb;
762}
763
764static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
765 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 },
766 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
767 .len = GENL_NAMSIZ - 1 },
768};
769
770static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
771{
772 struct sk_buff *msg;
773 struct genl_family *res = NULL;
774 int err = -EINVAL;
775
776 if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
777 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
778 res = genl_family_find_byid(id);
779 err = -ENOENT;
780 }
781
782 if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
783 char *name;
784
785 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
786 res = genl_family_find_byname(name);
787 err = -ENOENT;
788 }
789
790 if (res == NULL)
791 return err;
792
793 if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) {
794 /* family doesn't exist here */
795 return -ENOENT;
796 }
797
798 msg = ctrl_build_family_msg(res, info->snd_pid, info->snd_seq,
799 CTRL_CMD_NEWFAMILY);
800 if (IS_ERR(msg))
801 return PTR_ERR(msg);
802
803 return genlmsg_reply(msg, info);
804}
805
806static int genl_ctrl_event(int event, void *data)
807{
808 struct sk_buff *msg;
809 struct genl_family *family;
810 struct genl_multicast_group *grp;
811
812 /* genl is still initialising */
813 if (!init_net.genl_sock)
814 return 0;
815
816 switch (event) {
817 case CTRL_CMD_NEWFAMILY:
818 case CTRL_CMD_DELFAMILY:
819 family = data;
820 msg = ctrl_build_family_msg(family, 0, 0, event);
821 break;
822 case CTRL_CMD_NEWMCAST_GRP:
823 case CTRL_CMD_DELMCAST_GRP:
824 grp = data;
825 family = grp->family;
826 msg = ctrl_build_mcgrp_msg(data, 0, 0, event);
827 break;
828 default:
829 return -EINVAL;
830 }
831
832 if (IS_ERR(msg))
833 return PTR_ERR(msg);
834
835 if (!family->netnsok) {
836 genlmsg_multicast_netns(&init_net, msg, 0,
837 GENL_ID_CTRL, GFP_KERNEL);
838 } else {
839 rcu_read_lock();
840 genlmsg_multicast_allns(msg, 0, GENL_ID_CTRL, GFP_ATOMIC);
841 rcu_read_unlock();
842 }
843
844 return 0;
845}
846
847static struct genl_ops genl_ctrl_ops = {
848 .cmd = CTRL_CMD_GETFAMILY,
849 .doit = ctrl_getfamily,
850 .dumpit = ctrl_dumpfamily,
851 .policy = ctrl_policy,
852};
853
854static struct genl_multicast_group notify_grp = {
855 .name = "notify",
856};
857
858static int __net_init genl_pernet_init(struct net *net)
859{
860 /* we'll bump the group number right afterwards */
861 net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, 0,
862 genl_rcv, &genl_mutex,
863 THIS_MODULE);
864
865 if (!net->genl_sock && net_eq(net, &init_net))
866 panic("GENL: Cannot initialize generic netlink\n");
867
868 if (!net->genl_sock)
869 return -ENOMEM;
870
871 return 0;
872}
873
874static void __net_exit genl_pernet_exit(struct net *net)
875{
876 netlink_kernel_release(net->genl_sock);
877 net->genl_sock = NULL;
878}
879
880static struct pernet_operations genl_pernet_ops = {
881 .init = genl_pernet_init,
882 .exit = genl_pernet_exit,
883};
884
885static int __init genl_init(void)
886{
887 int i, err;
888
889 for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
890 INIT_LIST_HEAD(&family_ht[i]);
891
892 err = genl_register_family_with_ops(&genl_ctrl, &genl_ctrl_ops, 1);
893 if (err < 0)
894 goto problem;
895
896 netlink_set_nonroot(NETLINK_GENERIC, NL_NONROOT_RECV);
897
898 err = register_pernet_subsys(&genl_pernet_ops);
899 if (err)
900 goto problem;
901
902 err = genl_register_mc_group(&genl_ctrl, ¬ify_grp);
903 if (err < 0)
904 goto problem;
905
906 return 0;
907
908problem:
909 panic("GENL: Cannot register controller: %d\n", err);
910}
911
912subsys_initcall(genl_init);
913
914static int genlmsg_mcast(struct sk_buff *skb, u32 pid, unsigned long group,
915 gfp_t flags)
916{
917 struct sk_buff *tmp;
918 struct net *net, *prev = NULL;
919 int err;
920
921 for_each_net_rcu(net) {
922 if (prev) {
923 tmp = skb_clone(skb, flags);
924 if (!tmp) {
925 err = -ENOMEM;
926 goto error;
927 }
928 err = nlmsg_multicast(prev->genl_sock, tmp,
929 pid, group, flags);
930 if (err)
931 goto error;
932 }
933
934 prev = net;
935 }
936
937 return nlmsg_multicast(prev->genl_sock, skb, pid, group, flags);
938 error:
939 kfree_skb(skb);
940 return err;
941}
942
943int genlmsg_multicast_allns(struct sk_buff *skb, u32 pid, unsigned int group,
944 gfp_t flags)
945{
946 return genlmsg_mcast(skb, pid, group, flags);
947}
948EXPORT_SYMBOL(genlmsg_multicast_allns);