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 <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#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);