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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 <net/sock.h>
21#include <net/genetlink.h>
22
23static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */
24static DECLARE_RWSEM(cb_lock);
25
26atomic_t genl_sk_destructing_cnt = ATOMIC_INIT(0);
27DECLARE_WAIT_QUEUE_HEAD(genl_sk_destructing_waitq);
28
29void genl_lock(void)
30{
31 mutex_lock(&genl_mutex);
32}
33EXPORT_SYMBOL(genl_lock);
34
35void genl_unlock(void)
36{
37 mutex_unlock(&genl_mutex);
38}
39EXPORT_SYMBOL(genl_unlock);
40
41#ifdef CONFIG_LOCKDEP
42bool lockdep_genl_is_held(void)
43{
44 return lockdep_is_held(&genl_mutex);
45}
46EXPORT_SYMBOL(lockdep_genl_is_held);
47#endif
48
49static void genl_lock_all(void)
50{
51 down_write(&cb_lock);
52 genl_lock();
53}
54
55static void genl_unlock_all(void)
56{
57 genl_unlock();
58 up_write(&cb_lock);
59}
60
61#define GENL_FAM_TAB_SIZE 16
62#define GENL_FAM_TAB_MASK (GENL_FAM_TAB_SIZE - 1)
63
64static struct list_head family_ht[GENL_FAM_TAB_SIZE];
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, struct genl_family *family,
90 const struct genl_multicast_group *grp,
91 int grp_id);
92
93static inline unsigned int genl_family_hash(unsigned int id)
94{
95 return id & GENL_FAM_TAB_MASK;
96}
97
98static inline struct list_head *genl_family_chain(unsigned int id)
99{
100 return &family_ht[genl_family_hash(id)];
101}
102
103static struct genl_family *genl_family_find_byid(unsigned int id)
104{
105 struct genl_family *f;
106
107 list_for_each_entry(f, genl_family_chain(id), family_list)
108 if (f->id == id)
109 return f;
110
111 return NULL;
112}
113
114static struct genl_family *genl_family_find_byname(char *name)
115{
116 struct genl_family *f;
117 int i;
118
119 for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
120 list_for_each_entry(f, genl_family_chain(i), family_list)
121 if (strcmp(f->name, name) == 0)
122 return f;
123
124 return NULL;
125}
126
127static const struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family)
128{
129 int i;
130
131 for (i = 0; i < family->n_ops; i++)
132 if (family->ops[i].cmd == cmd)
133 return &family->ops[i];
134
135 return NULL;
136}
137
138/* Of course we are going to have problems once we hit
139 * 2^16 alive types, but that can only happen by year 2K
140*/
141static u16 genl_generate_id(void)
142{
143 static u16 id_gen_idx = GENL_MIN_ID;
144 int i;
145
146 for (i = 0; i <= GENL_MAX_ID - GENL_MIN_ID; i++) {
147 if (id_gen_idx != GENL_ID_VFS_DQUOT &&
148 id_gen_idx != GENL_ID_PMCRAID &&
149 !genl_family_find_byid(id_gen_idx))
150 return id_gen_idx;
151 if (++id_gen_idx > GENL_MAX_ID)
152 id_gen_idx = GENL_MIN_ID;
153 }
154
155 return 0;
156}
157
158static int genl_allocate_reserve_groups(int n_groups, int *first_id)
159{
160 unsigned long *new_groups;
161 int start = 0;
162 int i;
163 int id;
164 bool fits;
165
166 do {
167 if (start == 0)
168 id = find_first_zero_bit(mc_groups,
169 mc_groups_longs *
170 BITS_PER_LONG);
171 else
172 id = find_next_zero_bit(mc_groups,
173 mc_groups_longs * BITS_PER_LONG,
174 start);
175
176 fits = true;
177 for (i = id;
178 i < min_t(int, id + n_groups,
179 mc_groups_longs * BITS_PER_LONG);
180 i++) {
181 if (test_bit(i, mc_groups)) {
182 start = i;
183 fits = false;
184 break;
185 }
186 }
187
188 if (id + n_groups > mc_groups_longs * BITS_PER_LONG) {
189 unsigned long new_longs = mc_groups_longs +
190 BITS_TO_LONGS(n_groups);
191 size_t nlen = new_longs * sizeof(unsigned long);
192
193 if (mc_groups == &mc_group_start) {
194 new_groups = kzalloc(nlen, GFP_KERNEL);
195 if (!new_groups)
196 return -ENOMEM;
197 mc_groups = new_groups;
198 *mc_groups = mc_group_start;
199 } else {
200 new_groups = krealloc(mc_groups, nlen,
201 GFP_KERNEL);
202 if (!new_groups)
203 return -ENOMEM;
204 mc_groups = new_groups;
205 for (i = 0; i < BITS_TO_LONGS(n_groups); i++)
206 mc_groups[mc_groups_longs + i] = 0;
207 }
208 mc_groups_longs = new_longs;
209 }
210 } while (!fits);
211
212 for (i = id; i < id + n_groups; i++)
213 set_bit(i, mc_groups);
214 *first_id = id;
215 return 0;
216}
217
218static struct genl_family genl_ctrl;
219
220static int genl_validate_assign_mc_groups(struct genl_family *family)
221{
222 int first_id;
223 int n_groups = family->n_mcgrps;
224 int err = 0, i;
225 bool groups_allocated = false;
226
227 if (!n_groups)
228 return 0;
229
230 for (i = 0; i < n_groups; i++) {
231 const struct genl_multicast_group *grp = &family->mcgrps[i];
232
233 if (WARN_ON(grp->name[0] == '\0'))
234 return -EINVAL;
235 if (WARN_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL))
236 return -EINVAL;
237 }
238
239 /* special-case our own group and hacks */
240 if (family == &genl_ctrl) {
241 first_id = GENL_ID_CTRL;
242 BUG_ON(n_groups != 1);
243 } else if (strcmp(family->name, "NET_DM") == 0) {
244 first_id = 1;
245 BUG_ON(n_groups != 1);
246 } else if (family->id == GENL_ID_VFS_DQUOT) {
247 first_id = GENL_ID_VFS_DQUOT;
248 BUG_ON(n_groups != 1);
249 } else if (family->id == GENL_ID_PMCRAID) {
250 first_id = GENL_ID_PMCRAID;
251 BUG_ON(n_groups != 1);
252 } else {
253 groups_allocated = true;
254 err = genl_allocate_reserve_groups(n_groups, &first_id);
255 if (err)
256 return err;
257 }
258
259 family->mcgrp_offset = first_id;
260
261 /* if still initializing, can't and don't need to to realloc bitmaps */
262 if (!init_net.genl_sock)
263 return 0;
264
265 if (family->netnsok) {
266 struct net *net;
267
268 netlink_table_grab();
269 rcu_read_lock();
270 for_each_net_rcu(net) {
271 err = __netlink_change_ngroups(net->genl_sock,
272 mc_groups_longs * BITS_PER_LONG);
273 if (err) {
274 /*
275 * No need to roll back, can only fail if
276 * memory allocation fails and then the
277 * number of _possible_ groups has been
278 * increased on some sockets which is ok.
279 */
280 break;
281 }
282 }
283 rcu_read_unlock();
284 netlink_table_ungrab();
285 } else {
286 err = netlink_change_ngroups(init_net.genl_sock,
287 mc_groups_longs * BITS_PER_LONG);
288 }
289
290 if (groups_allocated && err) {
291 for (i = 0; i < family->n_mcgrps; i++)
292 clear_bit(family->mcgrp_offset + i, mc_groups);
293 }
294
295 return err;
296}
297
298static void genl_unregister_mc_groups(struct genl_family *family)
299{
300 struct net *net;
301 int i;
302
303 netlink_table_grab();
304 rcu_read_lock();
305 for_each_net_rcu(net) {
306 for (i = 0; i < family->n_mcgrps; i++)
307 __netlink_clear_multicast_users(
308 net->genl_sock, family->mcgrp_offset + i);
309 }
310 rcu_read_unlock();
311 netlink_table_ungrab();
312
313 for (i = 0; i < family->n_mcgrps; i++) {
314 int grp_id = family->mcgrp_offset + i;
315
316 if (grp_id != 1)
317 clear_bit(grp_id, mc_groups);
318 genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, family,
319 &family->mcgrps[i], grp_id);
320 }
321}
322
323static int genl_validate_ops(const struct genl_family *family)
324{
325 const struct genl_ops *ops = family->ops;
326 unsigned int n_ops = family->n_ops;
327 int i, j;
328
329 if (WARN_ON(n_ops && !ops))
330 return -EINVAL;
331
332 if (!n_ops)
333 return 0;
334
335 for (i = 0; i < n_ops; i++) {
336 if (ops[i].dumpit == NULL && ops[i].doit == NULL)
337 return -EINVAL;
338 for (j = i + 1; j < n_ops; j++)
339 if (ops[i].cmd == ops[j].cmd)
340 return -EINVAL;
341 }
342
343 return 0;
344}
345
346/**
347 * __genl_register_family - register a generic netlink family
348 * @family: generic netlink family
349 *
350 * Registers the specified family after validating it first. Only one
351 * family may be registered with the same family name or identifier.
352 * The family id may equal GENL_ID_GENERATE causing an unique id to
353 * be automatically generated and assigned.
354 *
355 * The family's ops array must already be assigned, you can use the
356 * genl_register_family_with_ops() helper function.
357 *
358 * Return 0 on success or a negative error code.
359 */
360int __genl_register_family(struct genl_family *family)
361{
362 int err = -EINVAL, i;
363
364 if (family->id && family->id < GENL_MIN_ID)
365 goto errout;
366
367 if (family->id > GENL_MAX_ID)
368 goto errout;
369
370 err = genl_validate_ops(family);
371 if (err)
372 return err;
373
374 genl_lock_all();
375
376 if (genl_family_find_byname(family->name)) {
377 err = -EEXIST;
378 goto errout_locked;
379 }
380
381 if (family->id == GENL_ID_GENERATE) {
382 u16 newid = genl_generate_id();
383
384 if (!newid) {
385 err = -ENOMEM;
386 goto errout_locked;
387 }
388
389 family->id = newid;
390 } else if (genl_family_find_byid(family->id)) {
391 err = -EEXIST;
392 goto errout_locked;
393 }
394
395 if (family->maxattr && !family->parallel_ops) {
396 family->attrbuf = kmalloc((family->maxattr+1) *
397 sizeof(struct nlattr *), GFP_KERNEL);
398 if (family->attrbuf == NULL) {
399 err = -ENOMEM;
400 goto errout_locked;
401 }
402 } else
403 family->attrbuf = NULL;
404
405 err = genl_validate_assign_mc_groups(family);
406 if (err)
407 goto errout_locked;
408
409 list_add_tail(&family->family_list, genl_family_chain(family->id));
410 genl_unlock_all();
411
412 /* send all events */
413 genl_ctrl_event(CTRL_CMD_NEWFAMILY, family, NULL, 0);
414 for (i = 0; i < family->n_mcgrps; i++)
415 genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, family,
416 &family->mcgrps[i], family->mcgrp_offset + i);
417
418 return 0;
419
420errout_locked:
421 genl_unlock_all();
422errout:
423 return err;
424}
425EXPORT_SYMBOL(__genl_register_family);
426
427/**
428 * genl_unregister_family - unregister generic netlink family
429 * @family: generic netlink family
430 *
431 * Unregisters the specified family.
432 *
433 * Returns 0 on success or a negative error code.
434 */
435int genl_unregister_family(struct genl_family *family)
436{
437 struct genl_family *rc;
438
439 genl_lock_all();
440
441 list_for_each_entry(rc, genl_family_chain(family->id), family_list) {
442 if (family->id != rc->id || strcmp(rc->name, family->name))
443 continue;
444
445 genl_unregister_mc_groups(family);
446
447 list_del(&rc->family_list);
448 family->n_ops = 0;
449 up_write(&cb_lock);
450 wait_event(genl_sk_destructing_waitq,
451 atomic_read(&genl_sk_destructing_cnt) == 0);
452 genl_unlock();
453
454 kfree(family->attrbuf);
455 genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 0);
456 return 0;
457 }
458
459 genl_unlock_all();
460
461 return -ENOENT;
462}
463EXPORT_SYMBOL(genl_unregister_family);
464
465/**
466 * genlmsg_put - Add generic netlink header to netlink message
467 * @skb: socket buffer holding the message
468 * @portid: netlink portid the message is addressed to
469 * @seq: sequence number (usually the one of the sender)
470 * @family: generic netlink family
471 * @flags: netlink message flags
472 * @cmd: generic netlink command
473 *
474 * Returns pointer to user specific header
475 */
476void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
477 struct genl_family *family, int flags, u8 cmd)
478{
479 struct nlmsghdr *nlh;
480 struct genlmsghdr *hdr;
481
482 nlh = nlmsg_put(skb, portid, seq, family->id, GENL_HDRLEN +
483 family->hdrsize, flags);
484 if (nlh == NULL)
485 return NULL;
486
487 hdr = nlmsg_data(nlh);
488 hdr->cmd = cmd;
489 hdr->version = family->version;
490 hdr->reserved = 0;
491
492 return (char *) hdr + GENL_HDRLEN;
493}
494EXPORT_SYMBOL(genlmsg_put);
495
496static int genl_lock_start(struct netlink_callback *cb)
497{
498 /* our ops are always const - netlink API doesn't propagate that */
499 const struct genl_ops *ops = cb->data;
500 int rc = 0;
501
502 if (ops->start) {
503 genl_lock();
504 rc = ops->start(cb);
505 genl_unlock();
506 }
507 return rc;
508}
509
510static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
511{
512 /* our ops are always const - netlink API doesn't propagate that */
513 const struct genl_ops *ops = cb->data;
514 int rc;
515
516 genl_lock();
517 rc = ops->dumpit(skb, cb);
518 genl_unlock();
519 return rc;
520}
521
522static int genl_lock_done(struct netlink_callback *cb)
523{
524 /* our ops are always const - netlink API doesn't propagate that */
525 const struct genl_ops *ops = cb->data;
526 int rc = 0;
527
528 if (ops->done) {
529 genl_lock();
530 rc = ops->done(cb);
531 genl_unlock();
532 }
533 return rc;
534}
535
536static int genl_family_rcv_msg(struct genl_family *family,
537 struct sk_buff *skb,
538 struct nlmsghdr *nlh)
539{
540 const struct genl_ops *ops;
541 struct net *net = sock_net(skb->sk);
542 struct genl_info info;
543 struct genlmsghdr *hdr = nlmsg_data(nlh);
544 struct nlattr **attrbuf;
545 int hdrlen, err;
546
547 /* this family doesn't exist in this netns */
548 if (!family->netnsok && !net_eq(net, &init_net))
549 return -ENOENT;
550
551 hdrlen = GENL_HDRLEN + family->hdrsize;
552 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
553 return -EINVAL;
554
555 ops = genl_get_cmd(hdr->cmd, family);
556 if (ops == NULL)
557 return -EOPNOTSUPP;
558
559 if ((ops->flags & GENL_ADMIN_PERM) &&
560 !netlink_capable(skb, CAP_NET_ADMIN))
561 return -EPERM;
562
563 if ((ops->flags & GENL_UNS_ADMIN_PERM) &&
564 !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
565 return -EPERM;
566
567 if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP) {
568 int rc;
569
570 if (ops->dumpit == NULL)
571 return -EOPNOTSUPP;
572
573 if (!family->parallel_ops) {
574 struct netlink_dump_control c = {
575 .module = family->module,
576 /* we have const, but the netlink API doesn't */
577 .data = (void *)ops,
578 .start = genl_lock_start,
579 .dump = genl_lock_dumpit,
580 .done = genl_lock_done,
581 };
582
583 genl_unlock();
584 rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
585 genl_lock();
586
587 } else {
588 struct netlink_dump_control c = {
589 .module = family->module,
590 .start = ops->start,
591 .dump = ops->dumpit,
592 .done = ops->done,
593 };
594
595 rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
596 }
597
598 return rc;
599 }
600
601 if (ops->doit == NULL)
602 return -EOPNOTSUPP;
603
604 if (family->maxattr && family->parallel_ops) {
605 attrbuf = kmalloc((family->maxattr+1) *
606 sizeof(struct nlattr *), GFP_KERNEL);
607 if (attrbuf == NULL)
608 return -ENOMEM;
609 } else
610 attrbuf = family->attrbuf;
611
612 if (attrbuf) {
613 err = nlmsg_parse(nlh, hdrlen, attrbuf, family->maxattr,
614 ops->policy);
615 if (err < 0)
616 goto out;
617 }
618
619 info.snd_seq = nlh->nlmsg_seq;
620 info.snd_portid = NETLINK_CB(skb).portid;
621 info.nlhdr = nlh;
622 info.genlhdr = nlmsg_data(nlh);
623 info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
624 info.attrs = attrbuf;
625 genl_info_net_set(&info, net);
626 memset(&info.user_ptr, 0, sizeof(info.user_ptr));
627
628 if (family->pre_doit) {
629 err = family->pre_doit(ops, skb, &info);
630 if (err)
631 goto out;
632 }
633
634 err = ops->doit(skb, &info);
635
636 if (family->post_doit)
637 family->post_doit(ops, skb, &info);
638
639out:
640 if (family->parallel_ops)
641 kfree(attrbuf);
642
643 return err;
644}
645
646static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
647{
648 struct genl_family *family;
649 int err;
650
651 family = genl_family_find_byid(nlh->nlmsg_type);
652 if (family == NULL)
653 return -ENOENT;
654
655 if (!family->parallel_ops)
656 genl_lock();
657
658 err = genl_family_rcv_msg(family, skb, nlh);
659
660 if (!family->parallel_ops)
661 genl_unlock();
662
663 return err;
664}
665
666static void genl_rcv(struct sk_buff *skb)
667{
668 down_read(&cb_lock);
669 netlink_rcv_skb(skb, &genl_rcv_msg);
670 up_read(&cb_lock);
671}
672
673/**************************************************************************
674 * Controller
675 **************************************************************************/
676
677static struct genl_family genl_ctrl = {
678 .id = GENL_ID_CTRL,
679 .name = "nlctrl",
680 .version = 0x2,
681 .maxattr = CTRL_ATTR_MAX,
682 .netnsok = true,
683};
684
685static int ctrl_fill_info(struct genl_family *family, u32 portid, u32 seq,
686 u32 flags, struct sk_buff *skb, u8 cmd)
687{
688 void *hdr;
689
690 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
691 if (hdr == NULL)
692 return -1;
693
694 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
695 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) ||
696 nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) ||
697 nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) ||
698 nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr))
699 goto nla_put_failure;
700
701 if (family->n_ops) {
702 struct nlattr *nla_ops;
703 int i;
704
705 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
706 if (nla_ops == NULL)
707 goto nla_put_failure;
708
709 for (i = 0; i < family->n_ops; i++) {
710 struct nlattr *nest;
711 const struct genl_ops *ops = &family->ops[i];
712 u32 op_flags = ops->flags;
713
714 if (ops->dumpit)
715 op_flags |= GENL_CMD_CAP_DUMP;
716 if (ops->doit)
717 op_flags |= GENL_CMD_CAP_DO;
718 if (ops->policy)
719 op_flags |= GENL_CMD_CAP_HASPOL;
720
721 nest = nla_nest_start(skb, i + 1);
722 if (nest == NULL)
723 goto nla_put_failure;
724
725 if (nla_put_u32(skb, CTRL_ATTR_OP_ID, ops->cmd) ||
726 nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, op_flags))
727 goto nla_put_failure;
728
729 nla_nest_end(skb, nest);
730 }
731
732 nla_nest_end(skb, nla_ops);
733 }
734
735 if (family->n_mcgrps) {
736 struct nlattr *nla_grps;
737 int i;
738
739 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
740 if (nla_grps == NULL)
741 goto nla_put_failure;
742
743 for (i = 0; i < family->n_mcgrps; i++) {
744 struct nlattr *nest;
745 const struct genl_multicast_group *grp;
746
747 grp = &family->mcgrps[i];
748
749 nest = nla_nest_start(skb, i + 1);
750 if (nest == NULL)
751 goto nla_put_failure;
752
753 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID,
754 family->mcgrp_offset + i) ||
755 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
756 grp->name))
757 goto nla_put_failure;
758
759 nla_nest_end(skb, nest);
760 }
761 nla_nest_end(skb, nla_grps);
762 }
763
764 genlmsg_end(skb, hdr);
765 return 0;
766
767nla_put_failure:
768 genlmsg_cancel(skb, hdr);
769 return -EMSGSIZE;
770}
771
772static int ctrl_fill_mcgrp_info(struct genl_family *family,
773 const struct genl_multicast_group *grp,
774 int grp_id, u32 portid, u32 seq, u32 flags,
775 struct sk_buff *skb, u8 cmd)
776{
777 void *hdr;
778 struct nlattr *nla_grps;
779 struct nlattr *nest;
780
781 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
782 if (hdr == NULL)
783 return -1;
784
785 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
786 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id))
787 goto nla_put_failure;
788
789 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
790 if (nla_grps == NULL)
791 goto nla_put_failure;
792
793 nest = nla_nest_start(skb, 1);
794 if (nest == NULL)
795 goto nla_put_failure;
796
797 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp_id) ||
798 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
799 grp->name))
800 goto nla_put_failure;
801
802 nla_nest_end(skb, nest);
803 nla_nest_end(skb, nla_grps);
804
805 genlmsg_end(skb, hdr);
806 return 0;
807
808nla_put_failure:
809 genlmsg_cancel(skb, hdr);
810 return -EMSGSIZE;
811}
812
813static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
814{
815
816 int i, n = 0;
817 struct genl_family *rt;
818 struct net *net = sock_net(skb->sk);
819 int chains_to_skip = cb->args[0];
820 int fams_to_skip = cb->args[1];
821
822 for (i = chains_to_skip; i < GENL_FAM_TAB_SIZE; i++) {
823 n = 0;
824 list_for_each_entry(rt, genl_family_chain(i), family_list) {
825 if (!rt->netnsok && !net_eq(net, &init_net))
826 continue;
827 if (++n < fams_to_skip)
828 continue;
829 if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid,
830 cb->nlh->nlmsg_seq, NLM_F_MULTI,
831 skb, CTRL_CMD_NEWFAMILY) < 0)
832 goto errout;
833 }
834
835 fams_to_skip = 0;
836 }
837
838errout:
839 cb->args[0] = i;
840 cb->args[1] = n;
841
842 return skb->len;
843}
844
845static struct sk_buff *ctrl_build_family_msg(struct genl_family *family,
846 u32 portid, int seq, u8 cmd)
847{
848 struct sk_buff *skb;
849 int err;
850
851 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
852 if (skb == NULL)
853 return ERR_PTR(-ENOBUFS);
854
855 err = ctrl_fill_info(family, portid, seq, 0, skb, cmd);
856 if (err < 0) {
857 nlmsg_free(skb);
858 return ERR_PTR(err);
859 }
860
861 return skb;
862}
863
864static struct sk_buff *
865ctrl_build_mcgrp_msg(struct genl_family *family,
866 const struct genl_multicast_group *grp,
867 int grp_id, u32 portid, int seq, u8 cmd)
868{
869 struct sk_buff *skb;
870 int err;
871
872 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
873 if (skb == NULL)
874 return ERR_PTR(-ENOBUFS);
875
876 err = ctrl_fill_mcgrp_info(family, grp, grp_id, portid,
877 seq, 0, skb, cmd);
878 if (err < 0) {
879 nlmsg_free(skb);
880 return ERR_PTR(err);
881 }
882
883 return skb;
884}
885
886static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
887 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 },
888 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
889 .len = GENL_NAMSIZ - 1 },
890};
891
892static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
893{
894 struct sk_buff *msg;
895 struct genl_family *res = NULL;
896 int err = -EINVAL;
897
898 if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
899 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
900 res = genl_family_find_byid(id);
901 err = -ENOENT;
902 }
903
904 if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
905 char *name;
906
907 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
908 res = genl_family_find_byname(name);
909#ifdef CONFIG_MODULES
910 if (res == NULL) {
911 genl_unlock();
912 up_read(&cb_lock);
913 request_module("net-pf-%d-proto-%d-family-%s",
914 PF_NETLINK, NETLINK_GENERIC, name);
915 down_read(&cb_lock);
916 genl_lock();
917 res = genl_family_find_byname(name);
918 }
919#endif
920 err = -ENOENT;
921 }
922
923 if (res == NULL)
924 return err;
925
926 if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) {
927 /* family doesn't exist here */
928 return -ENOENT;
929 }
930
931 msg = ctrl_build_family_msg(res, info->snd_portid, info->snd_seq,
932 CTRL_CMD_NEWFAMILY);
933 if (IS_ERR(msg))
934 return PTR_ERR(msg);
935
936 return genlmsg_reply(msg, info);
937}
938
939static int genl_ctrl_event(int event, struct genl_family *family,
940 const struct genl_multicast_group *grp,
941 int grp_id)
942{
943 struct sk_buff *msg;
944
945 /* genl is still initialising */
946 if (!init_net.genl_sock)
947 return 0;
948
949 switch (event) {
950 case CTRL_CMD_NEWFAMILY:
951 case CTRL_CMD_DELFAMILY:
952 WARN_ON(grp);
953 msg = ctrl_build_family_msg(family, 0, 0, event);
954 break;
955 case CTRL_CMD_NEWMCAST_GRP:
956 case CTRL_CMD_DELMCAST_GRP:
957 BUG_ON(!grp);
958 msg = ctrl_build_mcgrp_msg(family, grp, grp_id, 0, 0, event);
959 break;
960 default:
961 return -EINVAL;
962 }
963
964 if (IS_ERR(msg))
965 return PTR_ERR(msg);
966
967 if (!family->netnsok) {
968 genlmsg_multicast_netns(&genl_ctrl, &init_net, msg, 0,
969 0, GFP_KERNEL);
970 } else {
971 rcu_read_lock();
972 genlmsg_multicast_allns(&genl_ctrl, msg, 0,
973 0, GFP_ATOMIC);
974 rcu_read_unlock();
975 }
976
977 return 0;
978}
979
980static struct genl_ops genl_ctrl_ops[] = {
981 {
982 .cmd = CTRL_CMD_GETFAMILY,
983 .doit = ctrl_getfamily,
984 .dumpit = ctrl_dumpfamily,
985 .policy = ctrl_policy,
986 },
987};
988
989static struct genl_multicast_group genl_ctrl_groups[] = {
990 { .name = "notify", },
991};
992
993static int genl_bind(struct net *net, int group)
994{
995 int i, err = -ENOENT;
996
997 down_read(&cb_lock);
998 for (i = 0; i < GENL_FAM_TAB_SIZE; i++) {
999 struct genl_family *f;
1000
1001 list_for_each_entry(f, genl_family_chain(i), family_list) {
1002 if (group >= f->mcgrp_offset &&
1003 group < f->mcgrp_offset + f->n_mcgrps) {
1004 int fam_grp = group - f->mcgrp_offset;
1005
1006 if (!f->netnsok && net != &init_net)
1007 err = -ENOENT;
1008 else if (f->mcast_bind)
1009 err = f->mcast_bind(net, fam_grp);
1010 else
1011 err = 0;
1012 break;
1013 }
1014 }
1015 }
1016 up_read(&cb_lock);
1017
1018 return err;
1019}
1020
1021static void genl_unbind(struct net *net, int group)
1022{
1023 int i;
1024
1025 down_read(&cb_lock);
1026 for (i = 0; i < GENL_FAM_TAB_SIZE; i++) {
1027 struct genl_family *f;
1028
1029 list_for_each_entry(f, genl_family_chain(i), family_list) {
1030 if (group >= f->mcgrp_offset &&
1031 group < f->mcgrp_offset + f->n_mcgrps) {
1032 int fam_grp = group - f->mcgrp_offset;
1033
1034 if (f->mcast_unbind)
1035 f->mcast_unbind(net, fam_grp);
1036 break;
1037 }
1038 }
1039 }
1040 up_read(&cb_lock);
1041}
1042
1043static int __net_init genl_pernet_init(struct net *net)
1044{
1045 struct netlink_kernel_cfg cfg = {
1046 .input = genl_rcv,
1047 .flags = NL_CFG_F_NONROOT_RECV,
1048 .bind = genl_bind,
1049 .unbind = genl_unbind,
1050 };
1051
1052 /* we'll bump the group number right afterwards */
1053 net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg);
1054
1055 if (!net->genl_sock && net_eq(net, &init_net))
1056 panic("GENL: Cannot initialize generic netlink\n");
1057
1058 if (!net->genl_sock)
1059 return -ENOMEM;
1060
1061 return 0;
1062}
1063
1064static void __net_exit genl_pernet_exit(struct net *net)
1065{
1066 netlink_kernel_release(net->genl_sock);
1067 net->genl_sock = NULL;
1068}
1069
1070static struct pernet_operations genl_pernet_ops = {
1071 .init = genl_pernet_init,
1072 .exit = genl_pernet_exit,
1073};
1074
1075static int __init genl_init(void)
1076{
1077 int i, err;
1078
1079 for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
1080 INIT_LIST_HEAD(&family_ht[i]);
1081
1082 err = genl_register_family_with_ops_groups(&genl_ctrl, genl_ctrl_ops,
1083 genl_ctrl_groups);
1084 if (err < 0)
1085 goto problem;
1086
1087 err = register_pernet_subsys(&genl_pernet_ops);
1088 if (err)
1089 goto problem;
1090
1091 return 0;
1092
1093problem:
1094 panic("GENL: Cannot register controller: %d\n", err);
1095}
1096
1097subsys_initcall(genl_init);
1098
1099static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
1100 gfp_t flags)
1101{
1102 struct sk_buff *tmp;
1103 struct net *net, *prev = NULL;
1104 int err;
1105
1106 for_each_net_rcu(net) {
1107 if (prev) {
1108 tmp = skb_clone(skb, flags);
1109 if (!tmp) {
1110 err = -ENOMEM;
1111 goto error;
1112 }
1113 err = nlmsg_multicast(prev->genl_sock, tmp,
1114 portid, group, flags);
1115 if (err)
1116 goto error;
1117 }
1118
1119 prev = net;
1120 }
1121
1122 return nlmsg_multicast(prev->genl_sock, skb, portid, group, flags);
1123 error:
1124 kfree_skb(skb);
1125 return err;
1126}
1127
1128int genlmsg_multicast_allns(struct genl_family *family, struct sk_buff *skb,
1129 u32 portid, unsigned int group, gfp_t flags)
1130{
1131 if (WARN_ON_ONCE(group >= family->n_mcgrps))
1132 return -EINVAL;
1133 group = family->mcgrp_offset + group;
1134 return genlmsg_mcast(skb, portid, group, flags);
1135}
1136EXPORT_SYMBOL(genlmsg_multicast_allns);
1137
1138void genl_notify(struct genl_family *family, struct sk_buff *skb,
1139 struct genl_info *info, u32 group, gfp_t flags)
1140{
1141 struct net *net = genl_info_net(info);
1142 struct sock *sk = net->genl_sock;
1143 int report = 0;
1144
1145 if (info->nlhdr)
1146 report = nlmsg_report(info->nlhdr);
1147
1148 if (WARN_ON_ONCE(group >= family->n_mcgrps))
1149 return;
1150 group = family->mcgrp_offset + group;
1151 nlmsg_notify(sk, skb, info->snd_portid, group, report, flags);
1152}
1153EXPORT_SYMBOL(genl_notify);
1/*
2 * NETLINK Generic Netlink Family
3 *
4 * Authors: Jamal Hadi Salim
5 * Thomas Graf <tgraf@suug.ch>
6 * Johannes Berg <johannes@sipsolutions.net>
7 */
8
9#include <linux/module.h>
10#include <linux/kernel.h>
11#include <linux/slab.h>
12#include <linux/errno.h>
13#include <linux/types.h>
14#include <linux/socket.h>
15#include <linux/string.h>
16#include <linux/skbuff.h>
17#include <linux/mutex.h>
18#include <linux/bitmap.h>
19#include <net/sock.h>
20#include <net/genetlink.h>
21
22static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */
23
24void genl_lock(void)
25{
26 mutex_lock(&genl_mutex);
27}
28EXPORT_SYMBOL(genl_lock);
29
30void genl_unlock(void)
31{
32 mutex_unlock(&genl_mutex);
33}
34EXPORT_SYMBOL(genl_unlock);
35
36#ifdef CONFIG_PROVE_LOCKING
37int lockdep_genl_is_held(void)
38{
39 return lockdep_is_held(&genl_mutex);
40}
41EXPORT_SYMBOL(lockdep_genl_is_held);
42#endif
43
44#define GENL_FAM_TAB_SIZE 16
45#define GENL_FAM_TAB_MASK (GENL_FAM_TAB_SIZE - 1)
46
47static struct list_head family_ht[GENL_FAM_TAB_SIZE];
48/*
49 * Bitmap of multicast groups that are currently in use.
50 *
51 * To avoid an allocation at boot of just one unsigned long,
52 * declare it global instead.
53 * Bit 0 is marked as already used since group 0 is invalid.
54 */
55static unsigned long mc_group_start = 0x1;
56static unsigned long *mc_groups = &mc_group_start;
57static unsigned long mc_groups_longs = 1;
58
59static int genl_ctrl_event(int event, void *data);
60
61static inline unsigned int genl_family_hash(unsigned int id)
62{
63 return id & GENL_FAM_TAB_MASK;
64}
65
66static inline struct list_head *genl_family_chain(unsigned int id)
67{
68 return &family_ht[genl_family_hash(id)];
69}
70
71static struct genl_family *genl_family_find_byid(unsigned int id)
72{
73 struct genl_family *f;
74
75 list_for_each_entry(f, genl_family_chain(id), family_list)
76 if (f->id == id)
77 return f;
78
79 return NULL;
80}
81
82static struct genl_family *genl_family_find_byname(char *name)
83{
84 struct genl_family *f;
85 int i;
86
87 for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
88 list_for_each_entry(f, genl_family_chain(i), family_list)
89 if (strcmp(f->name, name) == 0)
90 return f;
91
92 return NULL;
93}
94
95static struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family)
96{
97 struct genl_ops *ops;
98
99 list_for_each_entry(ops, &family->ops_list, ops_list)
100 if (ops->cmd == cmd)
101 return ops;
102
103 return NULL;
104}
105
106/* Of course we are going to have problems once we hit
107 * 2^16 alive types, but that can only happen by year 2K
108*/
109static u16 genl_generate_id(void)
110{
111 static u16 id_gen_idx = GENL_MIN_ID;
112 int i;
113
114 for (i = 0; i <= GENL_MAX_ID - GENL_MIN_ID; i++) {
115 if (!genl_family_find_byid(id_gen_idx))
116 return id_gen_idx;
117 if (++id_gen_idx > GENL_MAX_ID)
118 id_gen_idx = GENL_MIN_ID;
119 }
120
121 return 0;
122}
123
124static struct genl_multicast_group notify_grp;
125
126/**
127 * genl_register_mc_group - register a multicast group
128 *
129 * Registers the specified multicast group and notifies userspace
130 * about the new group.
131 *
132 * Returns 0 on success or a negative error code.
133 *
134 * @family: The generic netlink family the group shall be registered for.
135 * @grp: The group to register, must have a name.
136 */
137int genl_register_mc_group(struct genl_family *family,
138 struct genl_multicast_group *grp)
139{
140 int id;
141 unsigned long *new_groups;
142 int err = 0;
143
144 BUG_ON(grp->name[0] == '\0');
145
146 genl_lock();
147
148 /* special-case our own group */
149 if (grp == ¬ify_grp)
150 id = GENL_ID_CTRL;
151 else
152 id = find_first_zero_bit(mc_groups,
153 mc_groups_longs * BITS_PER_LONG);
154
155
156 if (id >= mc_groups_longs * BITS_PER_LONG) {
157 size_t nlen = (mc_groups_longs + 1) * sizeof(unsigned long);
158
159 if (mc_groups == &mc_group_start) {
160 new_groups = kzalloc(nlen, GFP_KERNEL);
161 if (!new_groups) {
162 err = -ENOMEM;
163 goto out;
164 }
165 mc_groups = new_groups;
166 *mc_groups = mc_group_start;
167 } else {
168 new_groups = krealloc(mc_groups, nlen, GFP_KERNEL);
169 if (!new_groups) {
170 err = -ENOMEM;
171 goto out;
172 }
173 mc_groups = new_groups;
174 mc_groups[mc_groups_longs] = 0;
175 }
176 mc_groups_longs++;
177 }
178
179 if (family->netnsok) {
180 struct net *net;
181
182 netlink_table_grab();
183 rcu_read_lock();
184 for_each_net_rcu(net) {
185 err = __netlink_change_ngroups(net->genl_sock,
186 mc_groups_longs * BITS_PER_LONG);
187 if (err) {
188 /*
189 * No need to roll back, can only fail if
190 * memory allocation fails and then the
191 * number of _possible_ groups has been
192 * increased on some sockets which is ok.
193 */
194 rcu_read_unlock();
195 netlink_table_ungrab();
196 goto out;
197 }
198 }
199 rcu_read_unlock();
200 netlink_table_ungrab();
201 } else {
202 err = netlink_change_ngroups(init_net.genl_sock,
203 mc_groups_longs * BITS_PER_LONG);
204 if (err)
205 goto out;
206 }
207
208 grp->id = id;
209 set_bit(id, mc_groups);
210 list_add_tail(&grp->list, &family->mcast_groups);
211 grp->family = family;
212
213 genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, grp);
214 out:
215 genl_unlock();
216 return err;
217}
218EXPORT_SYMBOL(genl_register_mc_group);
219
220static void __genl_unregister_mc_group(struct genl_family *family,
221 struct genl_multicast_group *grp)
222{
223 struct net *net;
224 BUG_ON(grp->family != family);
225
226 netlink_table_grab();
227 rcu_read_lock();
228 for_each_net_rcu(net)
229 __netlink_clear_multicast_users(net->genl_sock, grp->id);
230 rcu_read_unlock();
231 netlink_table_ungrab();
232
233 clear_bit(grp->id, mc_groups);
234 list_del(&grp->list);
235 genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, grp);
236 grp->id = 0;
237 grp->family = NULL;
238}
239
240/**
241 * genl_unregister_mc_group - unregister a multicast group
242 *
243 * Unregisters the specified multicast group and notifies userspace
244 * about it. All current listeners on the group are removed.
245 *
246 * Note: It is not necessary to unregister all multicast groups before
247 * unregistering the family, unregistering the family will cause
248 * all assigned multicast groups to be unregistered automatically.
249 *
250 * @family: Generic netlink family the group belongs to.
251 * @grp: The group to unregister, must have been registered successfully
252 * previously.
253 */
254void genl_unregister_mc_group(struct genl_family *family,
255 struct genl_multicast_group *grp)
256{
257 genl_lock();
258 __genl_unregister_mc_group(family, grp);
259 genl_unlock();
260}
261EXPORT_SYMBOL(genl_unregister_mc_group);
262
263static void genl_unregister_mc_groups(struct genl_family *family)
264{
265 struct genl_multicast_group *grp, *tmp;
266
267 list_for_each_entry_safe(grp, tmp, &family->mcast_groups, list)
268 __genl_unregister_mc_group(family, grp);
269}
270
271/**
272 * genl_register_ops - register generic netlink operations
273 * @family: generic netlink family
274 * @ops: operations to be registered
275 *
276 * Registers the specified operations and assigns them to the specified
277 * family. Either a doit or dumpit callback must be specified or the
278 * operation will fail. Only one operation structure per command
279 * identifier may be registered.
280 *
281 * See include/net/genetlink.h for more documenation on the operations
282 * structure.
283 *
284 * Returns 0 on success or a negative error code.
285 */
286int genl_register_ops(struct genl_family *family, struct genl_ops *ops)
287{
288 int err = -EINVAL;
289
290 if (ops->dumpit == NULL && ops->doit == NULL)
291 goto errout;
292
293 if (genl_get_cmd(ops->cmd, family)) {
294 err = -EEXIST;
295 goto errout;
296 }
297
298 if (ops->dumpit)
299 ops->flags |= GENL_CMD_CAP_DUMP;
300 if (ops->doit)
301 ops->flags |= GENL_CMD_CAP_DO;
302 if (ops->policy)
303 ops->flags |= GENL_CMD_CAP_HASPOL;
304
305 genl_lock();
306 list_add_tail(&ops->ops_list, &family->ops_list);
307 genl_unlock();
308
309 genl_ctrl_event(CTRL_CMD_NEWOPS, ops);
310 err = 0;
311errout:
312 return err;
313}
314EXPORT_SYMBOL(genl_register_ops);
315
316/**
317 * genl_unregister_ops - unregister generic netlink operations
318 * @family: generic netlink family
319 * @ops: operations to be unregistered
320 *
321 * Unregisters the specified operations and unassigns them from the
322 * specified family. The operation blocks until the current message
323 * processing has finished and doesn't start again until the
324 * unregister process has finished.
325 *
326 * Note: It is not necessary to unregister all operations before
327 * unregistering the family, unregistering the family will cause
328 * all assigned operations to be unregistered automatically.
329 *
330 * Returns 0 on success or a negative error code.
331 */
332int genl_unregister_ops(struct genl_family *family, struct genl_ops *ops)
333{
334 struct genl_ops *rc;
335
336 genl_lock();
337 list_for_each_entry(rc, &family->ops_list, ops_list) {
338 if (rc == ops) {
339 list_del(&ops->ops_list);
340 genl_unlock();
341 genl_ctrl_event(CTRL_CMD_DELOPS, ops);
342 return 0;
343 }
344 }
345 genl_unlock();
346
347 return -ENOENT;
348}
349EXPORT_SYMBOL(genl_unregister_ops);
350
351/**
352 * genl_register_family - register a generic netlink family
353 * @family: generic netlink family
354 *
355 * Registers the specified family after validating it first. Only one
356 * family may be registered with the same family name or identifier.
357 * The family id may equal GENL_ID_GENERATE causing an unique id to
358 * be automatically generated and assigned.
359 *
360 * Return 0 on success or a negative error code.
361 */
362int genl_register_family(struct genl_family *family)
363{
364 int err = -EINVAL;
365
366 if (family->id && family->id < GENL_MIN_ID)
367 goto errout;
368
369 if (family->id > GENL_MAX_ID)
370 goto errout;
371
372 INIT_LIST_HEAD(&family->ops_list);
373 INIT_LIST_HEAD(&family->mcast_groups);
374
375 genl_lock();
376
377 if (genl_family_find_byname(family->name)) {
378 err = -EEXIST;
379 goto errout_locked;
380 }
381
382 if (family->id == GENL_ID_GENERATE) {
383 u16 newid = genl_generate_id();
384
385 if (!newid) {
386 err = -ENOMEM;
387 goto errout_locked;
388 }
389
390 family->id = newid;
391 } else if (genl_family_find_byid(family->id)) {
392 err = -EEXIST;
393 goto errout_locked;
394 }
395
396 if (family->maxattr) {
397 family->attrbuf = kmalloc((family->maxattr+1) *
398 sizeof(struct nlattr *), GFP_KERNEL);
399 if (family->attrbuf == NULL) {
400 err = -ENOMEM;
401 goto errout_locked;
402 }
403 } else
404 family->attrbuf = NULL;
405
406 list_add_tail(&family->family_list, genl_family_chain(family->id));
407 genl_unlock();
408
409 genl_ctrl_event(CTRL_CMD_NEWFAMILY, family);
410
411 return 0;
412
413errout_locked:
414 genl_unlock();
415errout:
416 return err;
417}
418EXPORT_SYMBOL(genl_register_family);
419
420/**
421 * genl_register_family_with_ops - register a generic netlink family
422 * @family: generic netlink family
423 * @ops: operations to be registered
424 * @n_ops: number of elements to register
425 *
426 * Registers the specified family and operations from the specified table.
427 * Only one family may be registered with the same family name or identifier.
428 *
429 * The family id may equal GENL_ID_GENERATE causing an unique id to
430 * be automatically generated and assigned.
431 *
432 * Either a doit or dumpit callback must be specified for every registered
433 * operation or the function will fail. Only one operation structure per
434 * command identifier may be registered.
435 *
436 * See include/net/genetlink.h for more documenation on the operations
437 * structure.
438 *
439 * This is equivalent to calling genl_register_family() followed by
440 * genl_register_ops() for every operation entry in the table taking
441 * care to unregister the family on error path.
442 *
443 * Return 0 on success or a negative error code.
444 */
445int genl_register_family_with_ops(struct genl_family *family,
446 struct genl_ops *ops, size_t n_ops)
447{
448 int err, i;
449
450 err = genl_register_family(family);
451 if (err)
452 return err;
453
454 for (i = 0; i < n_ops; ++i, ++ops) {
455 err = genl_register_ops(family, ops);
456 if (err)
457 goto err_out;
458 }
459 return 0;
460err_out:
461 genl_unregister_family(family);
462 return err;
463}
464EXPORT_SYMBOL(genl_register_family_with_ops);
465
466/**
467 * genl_unregister_family - unregister generic netlink family
468 * @family: generic netlink family
469 *
470 * Unregisters the specified family.
471 *
472 * Returns 0 on success or a negative error code.
473 */
474int genl_unregister_family(struct genl_family *family)
475{
476 struct genl_family *rc;
477
478 genl_lock();
479
480 genl_unregister_mc_groups(family);
481
482 list_for_each_entry(rc, genl_family_chain(family->id), family_list) {
483 if (family->id != rc->id || strcmp(rc->name, family->name))
484 continue;
485
486 list_del(&rc->family_list);
487 INIT_LIST_HEAD(&family->ops_list);
488 genl_unlock();
489
490 kfree(family->attrbuf);
491 genl_ctrl_event(CTRL_CMD_DELFAMILY, family);
492 return 0;
493 }
494
495 genl_unlock();
496
497 return -ENOENT;
498}
499EXPORT_SYMBOL(genl_unregister_family);
500
501/**
502 * genlmsg_put - Add generic netlink header to netlink message
503 * @skb: socket buffer holding the message
504 * @pid: netlink pid the message is addressed to
505 * @seq: sequence number (usually the one of the sender)
506 * @family: generic netlink family
507 * @flags netlink message flags
508 * @cmd: generic netlink command
509 *
510 * Returns pointer to user specific header
511 */
512void *genlmsg_put(struct sk_buff *skb, u32 pid, u32 seq,
513 struct genl_family *family, int flags, u8 cmd)
514{
515 struct nlmsghdr *nlh;
516 struct genlmsghdr *hdr;
517
518 nlh = nlmsg_put(skb, pid, seq, family->id, GENL_HDRLEN +
519 family->hdrsize, flags);
520 if (nlh == NULL)
521 return NULL;
522
523 hdr = nlmsg_data(nlh);
524 hdr->cmd = cmd;
525 hdr->version = family->version;
526 hdr->reserved = 0;
527
528 return (char *) hdr + GENL_HDRLEN;
529}
530EXPORT_SYMBOL(genlmsg_put);
531
532static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
533{
534 struct genl_ops *ops;
535 struct genl_family *family;
536 struct net *net = sock_net(skb->sk);
537 struct genl_info info;
538 struct genlmsghdr *hdr = nlmsg_data(nlh);
539 int hdrlen, err;
540
541 family = genl_family_find_byid(nlh->nlmsg_type);
542 if (family == NULL)
543 return -ENOENT;
544
545 /* this family doesn't exist in this netns */
546 if (!family->netnsok && !net_eq(net, &init_net))
547 return -ENOENT;
548
549 hdrlen = GENL_HDRLEN + family->hdrsize;
550 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
551 return -EINVAL;
552
553 ops = genl_get_cmd(hdr->cmd, family);
554 if (ops == NULL)
555 return -EOPNOTSUPP;
556
557 if ((ops->flags & GENL_ADMIN_PERM) &&
558 !capable(CAP_NET_ADMIN))
559 return -EPERM;
560
561 if (nlh->nlmsg_flags & NLM_F_DUMP) {
562 if (ops->dumpit == NULL)
563 return -EOPNOTSUPP;
564
565 genl_unlock();
566 {
567 struct netlink_dump_control c = {
568 .dump = ops->dumpit,
569 .done = ops->done,
570 };
571 err = netlink_dump_start(net->genl_sock, skb, nlh, &c);
572 }
573 genl_lock();
574 return err;
575 }
576
577 if (ops->doit == NULL)
578 return -EOPNOTSUPP;
579
580 if (family->attrbuf) {
581 err = nlmsg_parse(nlh, hdrlen, family->attrbuf, family->maxattr,
582 ops->policy);
583 if (err < 0)
584 return err;
585 }
586
587 info.snd_seq = nlh->nlmsg_seq;
588 info.snd_pid = NETLINK_CB(skb).pid;
589 info.nlhdr = nlh;
590 info.genlhdr = nlmsg_data(nlh);
591 info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
592 info.attrs = family->attrbuf;
593 genl_info_net_set(&info, net);
594 memset(&info.user_ptr, 0, sizeof(info.user_ptr));
595
596 if (family->pre_doit) {
597 err = family->pre_doit(ops, skb, &info);
598 if (err)
599 return err;
600 }
601
602 err = ops->doit(skb, &info);
603
604 if (family->post_doit)
605 family->post_doit(ops, skb, &info);
606
607 return err;
608}
609
610static void genl_rcv(struct sk_buff *skb)
611{
612 genl_lock();
613 netlink_rcv_skb(skb, &genl_rcv_msg);
614 genl_unlock();
615}
616
617/**************************************************************************
618 * Controller
619 **************************************************************************/
620
621static struct genl_family genl_ctrl = {
622 .id = GENL_ID_CTRL,
623 .name = "nlctrl",
624 .version = 0x2,
625 .maxattr = CTRL_ATTR_MAX,
626 .netnsok = true,
627};
628
629static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
630 u32 flags, struct sk_buff *skb, u8 cmd)
631{
632 void *hdr;
633
634 hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
635 if (hdr == NULL)
636 return -1;
637
638 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
639 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) ||
640 nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) ||
641 nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) ||
642 nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr))
643 goto nla_put_failure;
644
645 if (!list_empty(&family->ops_list)) {
646 struct nlattr *nla_ops;
647 struct genl_ops *ops;
648 int idx = 1;
649
650 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
651 if (nla_ops == NULL)
652 goto nla_put_failure;
653
654 list_for_each_entry(ops, &family->ops_list, ops_list) {
655 struct nlattr *nest;
656
657 nest = nla_nest_start(skb, idx++);
658 if (nest == NULL)
659 goto nla_put_failure;
660
661 if (nla_put_u32(skb, CTRL_ATTR_OP_ID, ops->cmd) ||
662 nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, ops->flags))
663 goto nla_put_failure;
664
665 nla_nest_end(skb, nest);
666 }
667
668 nla_nest_end(skb, nla_ops);
669 }
670
671 if (!list_empty(&family->mcast_groups)) {
672 struct genl_multicast_group *grp;
673 struct nlattr *nla_grps;
674 int idx = 1;
675
676 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
677 if (nla_grps == NULL)
678 goto nla_put_failure;
679
680 list_for_each_entry(grp, &family->mcast_groups, list) {
681 struct nlattr *nest;
682
683 nest = nla_nest_start(skb, idx++);
684 if (nest == NULL)
685 goto nla_put_failure;
686
687 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id) ||
688 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
689 grp->name))
690 goto nla_put_failure;
691
692 nla_nest_end(skb, nest);
693 }
694 nla_nest_end(skb, nla_grps);
695 }
696
697 return genlmsg_end(skb, hdr);
698
699nla_put_failure:
700 genlmsg_cancel(skb, hdr);
701 return -EMSGSIZE;
702}
703
704static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 pid,
705 u32 seq, u32 flags, struct sk_buff *skb,
706 u8 cmd)
707{
708 void *hdr;
709 struct nlattr *nla_grps;
710 struct nlattr *nest;
711
712 hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
713 if (hdr == NULL)
714 return -1;
715
716 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, grp->family->name) ||
717 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, grp->family->id))
718 goto nla_put_failure;
719
720 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
721 if (nla_grps == NULL)
722 goto nla_put_failure;
723
724 nest = nla_nest_start(skb, 1);
725 if (nest == NULL)
726 goto nla_put_failure;
727
728 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id) ||
729 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
730 grp->name))
731 goto nla_put_failure;
732
733 nla_nest_end(skb, nest);
734 nla_nest_end(skb, nla_grps);
735
736 return genlmsg_end(skb, hdr);
737
738nla_put_failure:
739 genlmsg_cancel(skb, hdr);
740 return -EMSGSIZE;
741}
742
743static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
744{
745
746 int i, n = 0;
747 struct genl_family *rt;
748 struct net *net = sock_net(skb->sk);
749 int chains_to_skip = cb->args[0];
750 int fams_to_skip = cb->args[1];
751
752 for (i = chains_to_skip; i < GENL_FAM_TAB_SIZE; i++) {
753 n = 0;
754 list_for_each_entry(rt, genl_family_chain(i), family_list) {
755 if (!rt->netnsok && !net_eq(net, &init_net))
756 continue;
757 if (++n < fams_to_skip)
758 continue;
759 if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).pid,
760 cb->nlh->nlmsg_seq, NLM_F_MULTI,
761 skb, CTRL_CMD_NEWFAMILY) < 0)
762 goto errout;
763 }
764
765 fams_to_skip = 0;
766 }
767
768errout:
769 cb->args[0] = i;
770 cb->args[1] = n;
771
772 return skb->len;
773}
774
775static struct sk_buff *ctrl_build_family_msg(struct genl_family *family,
776 u32 pid, int seq, u8 cmd)
777{
778 struct sk_buff *skb;
779 int err;
780
781 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
782 if (skb == NULL)
783 return ERR_PTR(-ENOBUFS);
784
785 err = ctrl_fill_info(family, pid, seq, 0, skb, cmd);
786 if (err < 0) {
787 nlmsg_free(skb);
788 return ERR_PTR(err);
789 }
790
791 return skb;
792}
793
794static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_multicast_group *grp,
795 u32 pid, int seq, u8 cmd)
796{
797 struct sk_buff *skb;
798 int err;
799
800 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
801 if (skb == NULL)
802 return ERR_PTR(-ENOBUFS);
803
804 err = ctrl_fill_mcgrp_info(grp, pid, seq, 0, skb, cmd);
805 if (err < 0) {
806 nlmsg_free(skb);
807 return ERR_PTR(err);
808 }
809
810 return skb;
811}
812
813static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
814 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 },
815 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
816 .len = GENL_NAMSIZ - 1 },
817};
818
819static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
820{
821 struct sk_buff *msg;
822 struct genl_family *res = NULL;
823 int err = -EINVAL;
824
825 if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
826 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
827 res = genl_family_find_byid(id);
828 err = -ENOENT;
829 }
830
831 if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
832 char *name;
833
834 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
835 res = genl_family_find_byname(name);
836#ifdef CONFIG_MODULES
837 if (res == NULL) {
838 genl_unlock();
839 request_module("net-pf-%d-proto-%d-family-%s",
840 PF_NETLINK, NETLINK_GENERIC, name);
841 genl_lock();
842 res = genl_family_find_byname(name);
843 }
844#endif
845 err = -ENOENT;
846 }
847
848 if (res == NULL)
849 return err;
850
851 if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) {
852 /* family doesn't exist here */
853 return -ENOENT;
854 }
855
856 msg = ctrl_build_family_msg(res, info->snd_pid, info->snd_seq,
857 CTRL_CMD_NEWFAMILY);
858 if (IS_ERR(msg))
859 return PTR_ERR(msg);
860
861 return genlmsg_reply(msg, info);
862}
863
864static int genl_ctrl_event(int event, void *data)
865{
866 struct sk_buff *msg;
867 struct genl_family *family;
868 struct genl_multicast_group *grp;
869
870 /* genl is still initialising */
871 if (!init_net.genl_sock)
872 return 0;
873
874 switch (event) {
875 case CTRL_CMD_NEWFAMILY:
876 case CTRL_CMD_DELFAMILY:
877 family = data;
878 msg = ctrl_build_family_msg(family, 0, 0, event);
879 break;
880 case CTRL_CMD_NEWMCAST_GRP:
881 case CTRL_CMD_DELMCAST_GRP:
882 grp = data;
883 family = grp->family;
884 msg = ctrl_build_mcgrp_msg(data, 0, 0, event);
885 break;
886 default:
887 return -EINVAL;
888 }
889
890 if (IS_ERR(msg))
891 return PTR_ERR(msg);
892
893 if (!family->netnsok) {
894 genlmsg_multicast_netns(&init_net, msg, 0,
895 GENL_ID_CTRL, GFP_KERNEL);
896 } else {
897 rcu_read_lock();
898 genlmsg_multicast_allns(msg, 0, GENL_ID_CTRL, GFP_ATOMIC);
899 rcu_read_unlock();
900 }
901
902 return 0;
903}
904
905static struct genl_ops genl_ctrl_ops = {
906 .cmd = CTRL_CMD_GETFAMILY,
907 .doit = ctrl_getfamily,
908 .dumpit = ctrl_dumpfamily,
909 .policy = ctrl_policy,
910};
911
912static struct genl_multicast_group notify_grp = {
913 .name = "notify",
914};
915
916static int __net_init genl_pernet_init(struct net *net)
917{
918 /* we'll bump the group number right afterwards */
919 net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, 0,
920 genl_rcv, &genl_mutex,
921 THIS_MODULE);
922
923 if (!net->genl_sock && net_eq(net, &init_net))
924 panic("GENL: Cannot initialize generic netlink\n");
925
926 if (!net->genl_sock)
927 return -ENOMEM;
928
929 return 0;
930}
931
932static void __net_exit genl_pernet_exit(struct net *net)
933{
934 netlink_kernel_release(net->genl_sock);
935 net->genl_sock = NULL;
936}
937
938static struct pernet_operations genl_pernet_ops = {
939 .init = genl_pernet_init,
940 .exit = genl_pernet_exit,
941};
942
943static int __init genl_init(void)
944{
945 int i, err;
946
947 for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
948 INIT_LIST_HEAD(&family_ht[i]);
949
950 err = genl_register_family_with_ops(&genl_ctrl, &genl_ctrl_ops, 1);
951 if (err < 0)
952 goto problem;
953
954 netlink_set_nonroot(NETLINK_GENERIC, NL_NONROOT_RECV);
955
956 err = register_pernet_subsys(&genl_pernet_ops);
957 if (err)
958 goto problem;
959
960 err = genl_register_mc_group(&genl_ctrl, ¬ify_grp);
961 if (err < 0)
962 goto problem;
963
964 return 0;
965
966problem:
967 panic("GENL: Cannot register controller: %d\n", err);
968}
969
970subsys_initcall(genl_init);
971
972static int genlmsg_mcast(struct sk_buff *skb, u32 pid, unsigned long group,
973 gfp_t flags)
974{
975 struct sk_buff *tmp;
976 struct net *net, *prev = NULL;
977 int err;
978
979 for_each_net_rcu(net) {
980 if (prev) {
981 tmp = skb_clone(skb, flags);
982 if (!tmp) {
983 err = -ENOMEM;
984 goto error;
985 }
986 err = nlmsg_multicast(prev->genl_sock, tmp,
987 pid, group, flags);
988 if (err)
989 goto error;
990 }
991
992 prev = net;
993 }
994
995 return nlmsg_multicast(prev->genl_sock, skb, pid, group, flags);
996 error:
997 kfree_skb(skb);
998 return err;
999}
1000
1001int genlmsg_multicast_allns(struct sk_buff *skb, u32 pid, unsigned int group,
1002 gfp_t flags)
1003{
1004 return genlmsg_mcast(skb, pid, group, flags);
1005}
1006EXPORT_SYMBOL(genlmsg_multicast_allns);
1007
1008void genl_notify(struct sk_buff *skb, struct net *net, u32 pid, u32 group,
1009 struct nlmsghdr *nlh, gfp_t flags)
1010{
1011 struct sock *sk = net->genl_sock;
1012 int report = 0;
1013
1014 if (nlh)
1015 report = nlmsg_report(nlh);
1016
1017 nlmsg_notify(sk, skb, pid, group, report, flags);
1018}
1019EXPORT_SYMBOL(genl_notify);