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powerpc/powernv: Report size of OPAL memcons log
[linux/fpc-iii.git] / net / netlink / genetlink.c
blobfb6e10fdb2174320c96608aea63d3c484d3625a0
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
24 static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */
25 static DECLARE_RWSEM(cb_lock);
26
27 atomic_t genl_sk_destructing_cnt = ATOMIC_INIT(0);
28 DECLARE_WAIT_QUEUE_HEAD(genl_sk_destructing_waitq);
29
30 void genl_lock(void)
31 {
32 mutex_lock(&genl_mutex);
33 }
34 EXPORT_SYMBOL(genl_lock);
35
36 void genl_unlock(void)
37 {
38 mutex_unlock(&genl_mutex);
39 }
40 EXPORT_SYMBOL(genl_unlock);
41
42 #ifdef CONFIG_LOCKDEP
43 bool lockdep_genl_is_held(void)
44 {
45 return lockdep_is_held(&genl_mutex);
46 }
47 EXPORT_SYMBOL(lockdep_genl_is_held);
48 #endif
49
50 static void genl_lock_all(void)
51 {
52 down_write(&cb_lock);
53 genl_lock();
54 }
55
56 static void genl_unlock_all(void)
57 {
58 genl_unlock();
59 up_write(&cb_lock);
60 }
61
62 static 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 */
82 static unsigned long mc_group_start = 0x3 | BIT(GENL_ID_CTRL) |
83 BIT(GENL_ID_VFS_DQUOT) |
84 BIT(GENL_ID_PMCRAID);
85 static unsigned long *mc_groups = &mc_group_start;
86 static unsigned long mc_groups_longs = 1;
87
88 static int genl_ctrl_event(int event, const struct genl_family *family,
89 const struct genl_multicast_group *grp,
90 int grp_id);
91
92 static const struct genl_family *genl_family_find_byid(unsigned int id)
93 {
94 return idr_find(&genl_fam_idr, id);
95 }
96
97 static 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
109 static 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
121 static 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
181 static struct genl_family genl_ctrl;
182
183 static 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
261 static 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
286 static 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 */
321 int 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
384 errout_remove:
385 idr_remove(&genl_fam_idr, family->id);
386 kfree(family->attrbuf);
387 errout_locked:
388 genl_unlock_all();
389 return err;
390 }
391 EXPORT_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 */
401 int 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 }
425 EXPORT_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 */
438 void *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 }
456 EXPORT_SYMBOL(genlmsg_put);
457
458 static 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
472 static 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
484 static 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
498 static 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
601 out:
602 if (family->parallel_ops)
603 kfree(attrbuf);
604
605 return err;
606 }
607
608 static 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
628 static 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
639 static struct genl_family genl_ctrl;
640
641 static 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
723 nla_put_failure:
724 genlmsg_cancel(skb, hdr);
725 return -EMSGSIZE;
726 }
727
728 static 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
764 nla_put_failure:
765 genlmsg_cancel(skb, hdr);
766 return -EMSGSIZE;
767 }
768
769 static 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 break;
788 }
789
790 cb->args[0] = n;
791 return skb->len;
792 }
793
794 static struct sk_buff *ctrl_build_family_msg(const struct genl_family *family,
795 u32 portid, int seq, u8 cmd)
796 {
797 struct sk_buff *skb;
798 int err;
799
800 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
801 if (skb == NULL)
802 return ERR_PTR(-ENOBUFS);
803
804 err = ctrl_fill_info(family, portid, seq, 0, skb, cmd);
805 if (err < 0) {
806 nlmsg_free(skb);
807 return ERR_PTR(err);
808 }
809
810 return skb;
811 }
812
813 static struct sk_buff *
814 ctrl_build_mcgrp_msg(const struct genl_family *family,
815 const struct genl_multicast_group *grp,
816 int grp_id, u32 portid, int seq, u8 cmd)
817 {
818 struct sk_buff *skb;
819 int err;
820
821 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
822 if (skb == NULL)
823 return ERR_PTR(-ENOBUFS);
824
825 err = ctrl_fill_mcgrp_info(family, grp, grp_id, portid,
826 seq, 0, skb, cmd);
827 if (err < 0) {
828 nlmsg_free(skb);
829 return ERR_PTR(err);
830 }
831
832 return skb;
833 }
834
835 static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
836 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 },
837 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
838 .len = GENL_NAMSIZ - 1 },
839 };
840
841 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
842 {
843 struct sk_buff *msg;
844 const struct genl_family *res = NULL;
845 int err = -EINVAL;
846
847 if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
848 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
849 res = genl_family_find_byid(id);
850 err = -ENOENT;
851 }
852
853 if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
854 char *name;
855
856 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
857 res = genl_family_find_byname(name);
858 #ifdef CONFIG_MODULES
859 if (res == NULL) {
860 genl_unlock();
861 up_read(&cb_lock);
862 request_module("net-pf-%d-proto-%d-family-%s",
863 PF_NETLINK, NETLINK_GENERIC, name);
864 down_read(&cb_lock);
865 genl_lock();
866 res = genl_family_find_byname(name);
867 }
868 #endif
869 err = -ENOENT;
870 }
871
872 if (res == NULL)
873 return err;
874
875 if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) {
876 /* family doesn't exist here */
877 return -ENOENT;
878 }
879
880 msg = ctrl_build_family_msg(res, info->snd_portid, info->snd_seq,
881 CTRL_CMD_NEWFAMILY);
882 if (IS_ERR(msg))
883 return PTR_ERR(msg);
884
885 return genlmsg_reply(msg, info);
886 }
887
888 static int genl_ctrl_event(int event, const struct genl_family *family,
889 const struct genl_multicast_group *grp,
890 int grp_id)
891 {
892 struct sk_buff *msg;
893
894 /* genl is still initialising */
895 if (!init_net.genl_sock)
896 return 0;
897
898 switch (event) {
899 case CTRL_CMD_NEWFAMILY:
900 case CTRL_CMD_DELFAMILY:
901 WARN_ON(grp);
902 msg = ctrl_build_family_msg(family, 0, 0, event);
903 break;
904 case CTRL_CMD_NEWMCAST_GRP:
905 case CTRL_CMD_DELMCAST_GRP:
906 BUG_ON(!grp);
907 msg = ctrl_build_mcgrp_msg(family, grp, grp_id, 0, 0, event);
908 break;
909 default:
910 return -EINVAL;
911 }
912
913 if (IS_ERR(msg))
914 return PTR_ERR(msg);
915
916 if (!family->netnsok) {
917 genlmsg_multicast_netns(&genl_ctrl, &init_net, msg, 0,
918 0, GFP_KERNEL);
919 } else {
920 rcu_read_lock();
921 genlmsg_multicast_allns(&genl_ctrl, msg, 0,
922 0, GFP_ATOMIC);
923 rcu_read_unlock();
924 }
925
926 return 0;
927 }
928
929 static const struct genl_ops genl_ctrl_ops[] = {
930 {
931 .cmd = CTRL_CMD_GETFAMILY,
932 .doit = ctrl_getfamily,
933 .dumpit = ctrl_dumpfamily,
934 .policy = ctrl_policy,
935 },
936 };
937
938 static const struct genl_multicast_group genl_ctrl_groups[] = {
939 { .name = "notify", },
940 };
941
942 static struct genl_family genl_ctrl __ro_after_init = {
943 .module = THIS_MODULE,
944 .ops = genl_ctrl_ops,
945 .n_ops = ARRAY_SIZE(genl_ctrl_ops),
946 .mcgrps = genl_ctrl_groups,
947 .n_mcgrps = ARRAY_SIZE(genl_ctrl_groups),
948 .id = GENL_ID_CTRL,
949 .name = "nlctrl",
950 .version = 0x2,
951 .maxattr = CTRL_ATTR_MAX,
952 .netnsok = true,
953 };
954
955 static int genl_bind(struct net *net, int group)
956 {
957 struct genl_family *f;
958 int err = -ENOENT;
959 unsigned int id;
960
961 down_read(&cb_lock);
962
963 idr_for_each_entry(&genl_fam_idr, f, id) {
964 if (group >= f->mcgrp_offset &&
965 group < f->mcgrp_offset + f->n_mcgrps) {
966 int fam_grp = group - f->mcgrp_offset;
967
968 if (!f->netnsok && net != &init_net)
969 err = -ENOENT;
970 else if (f->mcast_bind)
971 err = f->mcast_bind(net, fam_grp);
972 else
973 err = 0;
974 break;
975 }
976 }
977 up_read(&cb_lock);
978
979 return err;
980 }
981
982 static void genl_unbind(struct net *net, int group)
983 {
984 struct genl_family *f;
985 unsigned int id;
986
987 down_read(&cb_lock);
988
989 idr_for_each_entry(&genl_fam_idr, f, id) {
990 if (group >= f->mcgrp_offset &&
991 group < f->mcgrp_offset + f->n_mcgrps) {
992 int fam_grp = group - f->mcgrp_offset;
993
994 if (f->mcast_unbind)
995 f->mcast_unbind(net, fam_grp);
996 break;
997 }
998 }
999 up_read(&cb_lock);
1000 }
1001
1002 static int __net_init genl_pernet_init(struct net *net)
1003 {
1004 struct netlink_kernel_cfg cfg = {
1005 .input = genl_rcv,
1006 .flags = NL_CFG_F_NONROOT_RECV,
1007 .bind = genl_bind,
1008 .unbind = genl_unbind,
1009 };
1010
1011 /* we'll bump the group number right afterwards */
1012 net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg);
1013
1014 if (!net->genl_sock && net_eq(net, &init_net))
1015 panic("GENL: Cannot initialize generic netlink\n");
1016
1017 if (!net->genl_sock)
1018 return -ENOMEM;
1019
1020 return 0;
1021 }
1022
1023 static void __net_exit genl_pernet_exit(struct net *net)
1024 {
1025 netlink_kernel_release(net->genl_sock);
1026 net->genl_sock = NULL;
1027 }
1028
1029 static struct pernet_operations genl_pernet_ops = {
1030 .init = genl_pernet_init,
1031 .exit = genl_pernet_exit,
1032 };
1033
1034 static int __init genl_init(void)
1035 {
1036 int err;
1037
1038 err = genl_register_family(&genl_ctrl);
1039 if (err < 0)
1040 goto problem;
1041
1042 err = register_pernet_subsys(&genl_pernet_ops);
1043 if (err)
1044 goto problem;
1045
1046 return 0;
1047
1048 problem:
1049 panic("GENL: Cannot register controller: %d\n", err);
1050 }
1051
1052 subsys_initcall(genl_init);
1053
1054 /**
1055 * genl_family_attrbuf - return family's attrbuf
1056 * @family: the family
1057 *
1058 * Return the family's attrbuf, while validating that it's
1059 * actually valid to access it.
1060 *
1061 * You cannot use this function with a family that has parallel_ops
1062 * and you can only use it within (pre/post) doit/dumpit callbacks.
1063 */
1064 struct nlattr **genl_family_attrbuf(const struct genl_family *family)
1065 {
1066 if (!WARN_ON(family->parallel_ops))
1067 lockdep_assert_held(&genl_mutex);
1068
1069 return family->attrbuf;
1070 }
1071 EXPORT_SYMBOL(genl_family_attrbuf);
1072
1073 static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
1074 gfp_t flags)
1075 {
1076 struct sk_buff *tmp;
1077 struct net *net, *prev = NULL;
1078 int err;
1079
1080 for_each_net_rcu(net) {
1081 if (prev) {
1082 tmp = skb_clone(skb, flags);
1083 if (!tmp) {
1084 err = -ENOMEM;
1085 goto error;
1086 }
1087 err = nlmsg_multicast(prev->genl_sock, tmp,
1088 portid, group, flags);
1089 if (err)
1090 goto error;
1091 }
1092
1093 prev = net;
1094 }
1095
1096 return nlmsg_multicast(prev->genl_sock, skb, portid, group, flags);
1097 error:
1098 kfree_skb(skb);
1099 return err;
1100 }
1101
1102 int genlmsg_multicast_allns(const struct genl_family *family,
1103 struct sk_buff *skb, u32 portid,
1104 unsigned int group, gfp_t flags)
1105 {
1106 if (WARN_ON_ONCE(group >= family->n_mcgrps))
1107 return -EINVAL;
1108 group = family->mcgrp_offset + group;
1109 return genlmsg_mcast(skb, portid, group, flags);
1110 }
1111 EXPORT_SYMBOL(genlmsg_multicast_allns);
1112
1113 void genl_notify(const struct genl_family *family, struct sk_buff *skb,
1114 struct genl_info *info, u32 group, gfp_t flags)
1115 {
1116 struct net *net = genl_info_net(info);
1117 struct sock *sk = net->genl_sock;
1118 int report = 0;
1119
1120 if (info->nlhdr)
1121 report = nlmsg_report(info->nlhdr);
1122
1123 if (WARN_ON_ONCE(group >= family->n_mcgrps))
1124 return;
1125 group = family->mcgrp_offset + group;
1126 nlmsg_notify(sk, skb, info->snd_portid, group, report, flags);
1127 }
1128 EXPORT_SYMBOL(genl_notify);
Linux with added FPC-III support