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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 <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
26void genl_lock(void)
27{
28 mutex_lock(&genl_mutex);
29}
30EXPORT_SYMBOL(genl_lock);
31
32void genl_unlock(void)
33{
34 mutex_unlock(&genl_mutex);
35}
36EXPORT_SYMBOL(genl_unlock);
37
38#ifdef CONFIG_LOCKDEP
39int lockdep_genl_is_held(void)
40{
41 return lockdep_is_held(&genl_mutex);
42}
43EXPORT_SYMBOL(lockdep_genl_is_held);
44#endif
45
46static void genl_lock_all(void)
47{
48 down_write(&cb_lock);
49 genl_lock();
50}
51
52static void genl_unlock_all(void)
53{
54 genl_unlock();
55 up_write(&cb_lock);
56}
57
58#define GENL_FAM_TAB_SIZE 16
59#define GENL_FAM_TAB_MASK (GENL_FAM_TAB_SIZE - 1)
60
61static struct list_head family_ht[GENL_FAM_TAB_SIZE];
62/*
63 * Bitmap of multicast groups that are currently in use.
64 *
65 * To avoid an allocation at boot of just one unsigned long,
66 * declare it global instead.
67 * Bit 0 is marked as already used since group 0 is invalid.
68 * Bit 1 is marked as already used since the drop-monitor code
69 * abuses the API and thinks it can statically use group 1.
70 * That group will typically conflict with other groups that
71 * any proper users use.
72 * Bit 16 is marked as used since it's used for generic netlink
73 * and the code no longer marks pre-reserved IDs as used.
74 * Bit 17 is marked as already used since the VFS quota code
75 * also abused this API and relied on family == group ID, we
76 * cater to that by giving it a static family and group ID.
77 * Bit 18 is marked as already used since the PMCRAID driver
78 * did the same thing as the VFS quota code (maybe copied?)
79 */
80static unsigned long mc_group_start = 0x3 | BIT(GENL_ID_CTRL) |
81 BIT(GENL_ID_VFS_DQUOT) |
82 BIT(GENL_ID_PMCRAID);
83static unsigned long *mc_groups = &mc_group_start;
84static unsigned long mc_groups_longs = 1;
85
86static int genl_ctrl_event(int event, struct genl_family *family,
87 const struct genl_multicast_group *grp,
88 int grp_id);
89
90static inline unsigned int genl_family_hash(unsigned int id)
91{
92 return id & GENL_FAM_TAB_MASK;
93}
94
95static inline struct list_head *genl_family_chain(unsigned int id)
96{
97 return &family_ht[genl_family_hash(id)];
98}
99
100static struct genl_family *genl_family_find_byid(unsigned int id)
101{
102 struct genl_family *f;
103
104 list_for_each_entry(f, genl_family_chain(id), family_list)
105 if (f->id == id)
106 return f;
107
108 return NULL;
109}
110
111static struct genl_family *genl_family_find_byname(char *name)
112{
113 struct genl_family *f;
114 int i;
115
116 for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
117 list_for_each_entry(f, genl_family_chain(i), family_list)
118 if (strcmp(f->name, name) == 0)
119 return f;
120
121 return NULL;
122}
123
124static const struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family)
125{
126 int i;
127
128 for (i = 0; i < family->n_ops; i++)
129 if (family->ops[i].cmd == cmd)
130 return &family->ops[i];
131
132 return NULL;
133}
134
135/* Of course we are going to have problems once we hit
136 * 2^16 alive types, but that can only happen by year 2K
137*/
138static u16 genl_generate_id(void)
139{
140 static u16 id_gen_idx = GENL_MIN_ID;
141 int i;
142
143 for (i = 0; i <= GENL_MAX_ID - GENL_MIN_ID; i++) {
144 if (id_gen_idx != GENL_ID_VFS_DQUOT &&
145 id_gen_idx != GENL_ID_PMCRAID &&
146 !genl_family_find_byid(id_gen_idx))
147 return id_gen_idx;
148 if (++id_gen_idx > GENL_MAX_ID)
149 id_gen_idx = GENL_MIN_ID;
150 }
151
152 return 0;
153}
154
155static int genl_allocate_reserve_groups(int n_groups, int *first_id)
156{
157 unsigned long *new_groups;
158 int start = 0;
159 int i;
160 int id;
161 bool fits;
162
163 do {
164 if (start == 0)
165 id = find_first_zero_bit(mc_groups,
166 mc_groups_longs *
167 BITS_PER_LONG);
168 else
169 id = find_next_zero_bit(mc_groups,
170 mc_groups_longs * BITS_PER_LONG,
171 start);
172
173 fits = true;
174 for (i = id;
175 i < min_t(int, id + n_groups,
176 mc_groups_longs * BITS_PER_LONG);
177 i++) {
178 if (test_bit(i, mc_groups)) {
179 start = i;
180 fits = false;
181 break;
182 }
183 }
184
185 if (id >= mc_groups_longs * BITS_PER_LONG) {
186 unsigned long new_longs = mc_groups_longs +
187 BITS_TO_LONGS(n_groups);
188 size_t nlen = new_longs * sizeof(unsigned long);
189
190 if (mc_groups == &mc_group_start) {
191 new_groups = kzalloc(nlen, GFP_KERNEL);
192 if (!new_groups)
193 return -ENOMEM;
194 mc_groups = new_groups;
195 *mc_groups = mc_group_start;
196 } else {
197 new_groups = krealloc(mc_groups, nlen,
198 GFP_KERNEL);
199 if (!new_groups)
200 return -ENOMEM;
201 mc_groups = new_groups;
202 for (i = 0; i < BITS_TO_LONGS(n_groups); i++)
203 mc_groups[mc_groups_longs + i] = 0;
204 }
205 mc_groups_longs = new_longs;
206 }
207 } while (!fits);
208
209 for (i = id; i < id + n_groups; i++)
210 set_bit(i, mc_groups);
211 *first_id = id;
212 return 0;
213}
214
215static struct genl_family genl_ctrl;
216
217static int genl_validate_assign_mc_groups(struct genl_family *family)
218{
219 int first_id;
220 int n_groups = family->n_mcgrps;
221 int err = 0, i;
222 bool groups_allocated = false;
223
224 if (!n_groups)
225 return 0;
226
227 for (i = 0; i < n_groups; i++) {
228 const struct genl_multicast_group *grp = &family->mcgrps[i];
229
230 if (WARN_ON(grp->name[0] == '\0'))
231 return -EINVAL;
232 if (WARN_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL))
233 return -EINVAL;
234 }
235
236 /* special-case our own group and hacks */
237 if (family == &genl_ctrl) {
238 first_id = GENL_ID_CTRL;
239 BUG_ON(n_groups != 1);
240 } else if (strcmp(family->name, "NET_DM") == 0) {
241 first_id = 1;
242 BUG_ON(n_groups != 1);
243 } else if (family->id == GENL_ID_VFS_DQUOT) {
244 first_id = GENL_ID_VFS_DQUOT;
245 BUG_ON(n_groups != 1);
246 } else if (family->id == GENL_ID_PMCRAID) {
247 first_id = GENL_ID_PMCRAID;
248 BUG_ON(n_groups != 1);
249 } else {
250 groups_allocated = true;
251 err = genl_allocate_reserve_groups(n_groups, &first_id);
252 if (err)
253 return err;
254 }
255
256 family->mcgrp_offset = first_id;
257
258 /* if still initializing, can't and don't need to to realloc bitmaps */
259 if (!init_net.genl_sock)
260 return 0;
261
262 if (family->netnsok) {
263 struct net *net;
264
265 netlink_table_grab();
266 rcu_read_lock();
267 for_each_net_rcu(net) {
268 err = __netlink_change_ngroups(net->genl_sock,
269 mc_groups_longs * BITS_PER_LONG);
270 if (err) {
271 /*
272 * No need to roll back, can only fail if
273 * memory allocation fails and then the
274 * number of _possible_ groups has been
275 * increased on some sockets which is ok.
276 */
277 break;
278 }
279 }
280 rcu_read_unlock();
281 netlink_table_ungrab();
282 } else {
283 err = netlink_change_ngroups(init_net.genl_sock,
284 mc_groups_longs * BITS_PER_LONG);
285 }
286
287 if (groups_allocated && err) {
288 for (i = 0; i < family->n_mcgrps; i++)
289 clear_bit(family->mcgrp_offset + i, mc_groups);
290 }
291
292 return err;
293}
294
295static void genl_unregister_mc_groups(struct genl_family *family)
296{
297 struct net *net;
298 int i;
299
300 netlink_table_grab();
301 rcu_read_lock();
302 for_each_net_rcu(net) {
303 for (i = 0; i < family->n_mcgrps; i++)
304 __netlink_clear_multicast_users(
305 net->genl_sock, family->mcgrp_offset + i);
306 }
307 rcu_read_unlock();
308 netlink_table_ungrab();
309
310 for (i = 0; i < family->n_mcgrps; i++) {
311 int grp_id = family->mcgrp_offset + i;
312
313 if (grp_id != 1)
314 clear_bit(grp_id, mc_groups);
315 genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, family,
316 &family->mcgrps[i], grp_id);
317 }
318}
319
320static int genl_validate_ops(struct genl_family *family)
321{
322 const struct genl_ops *ops = family->ops;
323 unsigned int n_ops = family->n_ops;
324 int i, j;
325
326 if (WARN_ON(n_ops && !ops))
327 return -EINVAL;
328
329 if (!n_ops)
330 return 0;
331
332 for (i = 0; i < n_ops; i++) {
333 if (ops[i].dumpit == NULL && ops[i].doit == NULL)
334 return -EINVAL;
335 for (j = i + 1; j < n_ops; j++)
336 if (ops[i].cmd == ops[j].cmd)
337 return -EINVAL;
338 }
339
340 /* family is not registered yet, so no locking needed */
341 family->ops = ops;
342 family->n_ops = n_ops;
343
344 return 0;
345}
346
347/**
348 * __genl_register_family - register a generic netlink family
349 * @family: generic netlink family
350 *
351 * Registers the specified family after validating it first. Only one
352 * family may be registered with the same family name or identifier.
353 * The family id may equal GENL_ID_GENERATE causing an unique id to
354 * be automatically generated and assigned.
355 *
356 * The family's ops array must already be assigned, you can use the
357 * genl_register_family_with_ops() helper function.
358 *
359 * Return 0 on success or a negative error code.
360 */
361int __genl_register_family(struct genl_family *family)
362{
363 int err = -EINVAL, i;
364
365 if (family->id && family->id < GENL_MIN_ID)
366 goto errout;
367
368 if (family->id > GENL_MAX_ID)
369 goto errout;
370
371 err = genl_validate_ops(family);
372 if (err)
373 return err;
374
375 genl_lock_all();
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 && !family->parallel_ops) {
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 err = genl_validate_assign_mc_groups(family);
407 if (err)
408 goto errout_locked;
409
410 list_add_tail(&family->family_list, genl_family_chain(family->id));
411 genl_unlock_all();
412
413 /* send all events */
414 genl_ctrl_event(CTRL_CMD_NEWFAMILY, family, NULL, 0);
415 for (i = 0; i < family->n_mcgrps; i++)
416 genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, family,
417 &family->mcgrps[i], family->mcgrp_offset + i);
418
419 return 0;
420
421errout_locked:
422 genl_unlock_all();
423errout:
424 return err;
425}
426EXPORT_SYMBOL(__genl_register_family);
427
428/**
429 * genl_unregister_family - unregister generic netlink family
430 * @family: generic netlink family
431 *
432 * Unregisters the specified family.
433 *
434 * Returns 0 on success or a negative error code.
435 */
436int genl_unregister_family(struct genl_family *family)
437{
438 struct genl_family *rc;
439
440 genl_lock_all();
441
442 genl_unregister_mc_groups(family);
443
444 list_for_each_entry(rc, genl_family_chain(family->id), family_list) {
445 if (family->id != rc->id || strcmp(rc->name, family->name))
446 continue;
447
448 list_del(&rc->family_list);
449 family->n_ops = 0;
450 genl_unlock_all();
451
452 kfree(family->attrbuf);
453 genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 0);
454 return 0;
455 }
456
457 genl_unlock_all();
458
459 return -ENOENT;
460}
461EXPORT_SYMBOL(genl_unregister_family);
462
463/**
464 * genlmsg_new_unicast - Allocate generic netlink message for unicast
465 * @payload: size of the message payload
466 * @info: information on destination
467 * @flags: the type of memory to allocate
468 *
469 * Allocates a new sk_buff large enough to cover the specified payload
470 * plus required Netlink headers. Will check receiving socket for
471 * memory mapped i/o capability and use it if enabled. Will fall back
472 * to non-mapped skb if message size exceeds the frame size of the ring.
473 */
474struct sk_buff *genlmsg_new_unicast(size_t payload, struct genl_info *info,
475 gfp_t flags)
476{
477 size_t len = nlmsg_total_size(genlmsg_total_size(payload));
478
479 return netlink_alloc_skb(info->dst_sk, len, info->snd_portid, flags);
480}
481EXPORT_SYMBOL_GPL(genlmsg_new_unicast);
482
483/**
484 * genlmsg_put - Add generic netlink header to netlink message
485 * @skb: socket buffer holding the message
486 * @portid: netlink portid the message is addressed to
487 * @seq: sequence number (usually the one of the sender)
488 * @family: generic netlink family
489 * @flags: netlink message flags
490 * @cmd: generic netlink command
491 *
492 * Returns pointer to user specific header
493 */
494void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
495 struct genl_family *family, int flags, u8 cmd)
496{
497 struct nlmsghdr *nlh;
498 struct genlmsghdr *hdr;
499
500 nlh = nlmsg_put(skb, portid, seq, family->id, GENL_HDRLEN +
501 family->hdrsize, flags);
502 if (nlh == NULL)
503 return NULL;
504
505 hdr = nlmsg_data(nlh);
506 hdr->cmd = cmd;
507 hdr->version = family->version;
508 hdr->reserved = 0;
509
510 return (char *) hdr + GENL_HDRLEN;
511}
512EXPORT_SYMBOL(genlmsg_put);
513
514static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
515{
516 /* our ops are always const - netlink API doesn't propagate that */
517 const struct genl_ops *ops = cb->data;
518 int rc;
519
520 genl_lock();
521 rc = ops->dumpit(skb, cb);
522 genl_unlock();
523 return rc;
524}
525
526static int genl_lock_done(struct netlink_callback *cb)
527{
528 /* our ops are always const - netlink API doesn't propagate that */
529 const struct genl_ops *ops = cb->data;
530 int rc = 0;
531
532 if (ops->done) {
533 genl_lock();
534 rc = ops->done(cb);
535 genl_unlock();
536 }
537 return rc;
538}
539
540static int genl_family_rcv_msg(struct genl_family *family,
541 struct sk_buff *skb,
542 struct nlmsghdr *nlh)
543{
544 const struct genl_ops *ops;
545 struct net *net = sock_net(skb->sk);
546 struct genl_info info;
547 struct genlmsghdr *hdr = nlmsg_data(nlh);
548 struct nlattr **attrbuf;
549 int hdrlen, err;
550
551 /* this family doesn't exist in this netns */
552 if (!family->netnsok && !net_eq(net, &init_net))
553 return -ENOENT;
554
555 hdrlen = GENL_HDRLEN + family->hdrsize;
556 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
557 return -EINVAL;
558
559 ops = genl_get_cmd(hdr->cmd, family);
560 if (ops == NULL)
561 return -EOPNOTSUPP;
562
563 if ((ops->flags & GENL_ADMIN_PERM) &&
564 !netlink_capable(skb, 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 .dump = genl_lock_dumpit,
579 .done = genl_lock_done,
580 };
581
582 genl_unlock();
583 rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
584 genl_lock();
585
586 } else {
587 struct netlink_dump_control c = {
588 .module = family->module,
589 .dump = ops->dumpit,
590 .done = ops->done,
591 };
592
593 rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
594 }
595
596 return rc;
597 }
598
599 if (ops->doit == NULL)
600 return -EOPNOTSUPP;
601
602 if (family->maxattr && family->parallel_ops) {
603 attrbuf = kmalloc((family->maxattr+1) *
604 sizeof(struct nlattr *), GFP_KERNEL);
605 if (attrbuf == NULL)
606 return -ENOMEM;
607 } else
608 attrbuf = family->attrbuf;
609
610 if (attrbuf) {
611 err = nlmsg_parse(nlh, hdrlen, attrbuf, family->maxattr,
612 ops->policy);
613 if (err < 0)
614 goto out;
615 }
616
617 info.snd_seq = nlh->nlmsg_seq;
618 info.snd_portid = NETLINK_CB(skb).portid;
619 info.nlhdr = nlh;
620 info.genlhdr = nlmsg_data(nlh);
621 info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
622 info.attrs = attrbuf;
623 info.dst_sk = skb->sk;
624 genl_info_net_set(&info, net);
625 memset(&info.user_ptr, 0, sizeof(info.user_ptr));
626
627 if (family->pre_doit) {
628 err = family->pre_doit(ops, skb, &info);
629 if (err)
630 goto out;
631 }
632
633 err = ops->doit(skb, &info);
634
635 if (family->post_doit)
636 family->post_doit(ops, skb, &info);
637
638out:
639 if (family->parallel_ops)
640 kfree(attrbuf);
641
642 return err;
643}
644
645static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
646{
647 struct genl_family *family;
648 int err;
649
650 family = genl_family_find_byid(nlh->nlmsg_type);
651 if (family == NULL)
652 return -ENOENT;
653
654 if (!family->parallel_ops)
655 genl_lock();
656
657 err = genl_family_rcv_msg(family, skb, nlh);
658
659 if (!family->parallel_ops)
660 genl_unlock();
661
662 return err;
663}
664
665static void genl_rcv(struct sk_buff *skb)
666{
667 down_read(&cb_lock);
668 netlink_rcv_skb(skb, &genl_rcv_msg);
669 up_read(&cb_lock);
670}
671
672/**************************************************************************
673 * Controller
674 **************************************************************************/
675
676static struct genl_family genl_ctrl = {
677 .id = GENL_ID_CTRL,
678 .name = "nlctrl",
679 .version = 0x2,
680 .maxattr = CTRL_ATTR_MAX,
681 .netnsok = true,
682};
683
684static int ctrl_fill_info(struct genl_family *family, u32 portid, u32 seq,
685 u32 flags, struct sk_buff *skb, u8 cmd)
686{
687 void *hdr;
688
689 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
690 if (hdr == NULL)
691 return -1;
692
693 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
694 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) ||
695 nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) ||
696 nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) ||
697 nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr))
698 goto nla_put_failure;
699
700 if (family->n_ops) {
701 struct nlattr *nla_ops;
702 int i;
703
704 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
705 if (nla_ops == NULL)
706 goto nla_put_failure;
707
708 for (i = 0; i < family->n_ops; i++) {
709 struct nlattr *nest;
710 const struct genl_ops *ops = &family->ops[i];
711 u32 op_flags = ops->flags;
712
713 if (ops->dumpit)
714 op_flags |= GENL_CMD_CAP_DUMP;
715 if (ops->doit)
716 op_flags |= GENL_CMD_CAP_DO;
717 if (ops->policy)
718 op_flags |= GENL_CMD_CAP_HASPOL;
719
720 nest = nla_nest_start(skb, i + 1);
721 if (nest == NULL)
722 goto nla_put_failure;
723
724 if (nla_put_u32(skb, CTRL_ATTR_OP_ID, ops->cmd) ||
725 nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, op_flags))
726 goto nla_put_failure;
727
728 nla_nest_end(skb, nest);
729 }
730
731 nla_nest_end(skb, nla_ops);
732 }
733
734 if (family->n_mcgrps) {
735 struct nlattr *nla_grps;
736 int i;
737
738 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
739 if (nla_grps == NULL)
740 goto nla_put_failure;
741
742 for (i = 0; i < family->n_mcgrps; i++) {
743 struct nlattr *nest;
744 const struct genl_multicast_group *grp;
745
746 grp = &family->mcgrps[i];
747
748 nest = nla_nest_start(skb, i + 1);
749 if (nest == NULL)
750 goto nla_put_failure;
751
752 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID,
753 family->mcgrp_offset + i) ||
754 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
755 grp->name))
756 goto nla_put_failure;
757
758 nla_nest_end(skb, nest);
759 }
760 nla_nest_end(skb, nla_grps);
761 }
762
763 return genlmsg_end(skb, hdr);
764
765nla_put_failure:
766 genlmsg_cancel(skb, hdr);
767 return -EMSGSIZE;
768}
769
770static int ctrl_fill_mcgrp_info(struct genl_family *family,
771 const struct genl_multicast_group *grp,
772 int grp_id, u32 portid, u32 seq, u32 flags,
773 struct sk_buff *skb, u8 cmd)
774{
775 void *hdr;
776 struct nlattr *nla_grps;
777 struct nlattr *nest;
778
779 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
780 if (hdr == NULL)
781 return -1;
782
783 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
784 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id))
785 goto nla_put_failure;
786
787 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
788 if (nla_grps == NULL)
789 goto nla_put_failure;
790
791 nest = nla_nest_start(skb, 1);
792 if (nest == NULL)
793 goto nla_put_failure;
794
795 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp_id) ||
796 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
797 grp->name))
798 goto nla_put_failure;
799
800 nla_nest_end(skb, nest);
801 nla_nest_end(skb, nla_grps);
802
803 return genlmsg_end(skb, hdr);
804
805nla_put_failure:
806 genlmsg_cancel(skb, hdr);
807 return -EMSGSIZE;
808}
809
810static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
811{
812
813 int i, n = 0;
814 struct genl_family *rt;
815 struct net *net = sock_net(skb->sk);
816 int chains_to_skip = cb->args[0];
817 int fams_to_skip = cb->args[1];
818
819 for (i = chains_to_skip; i < GENL_FAM_TAB_SIZE; i++) {
820 n = 0;
821 list_for_each_entry(rt, genl_family_chain(i), family_list) {
822 if (!rt->netnsok && !net_eq(net, &init_net))
823 continue;
824 if (++n < fams_to_skip)
825 continue;
826 if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid,
827 cb->nlh->nlmsg_seq, NLM_F_MULTI,
828 skb, CTRL_CMD_NEWFAMILY) < 0)
829 goto errout;
830 }
831
832 fams_to_skip = 0;
833 }
834
835errout:
836 cb->args[0] = i;
837 cb->args[1] = n;
838
839 return skb->len;
840}
841
842static struct sk_buff *ctrl_build_family_msg(struct genl_family *family,
843 u32 portid, int seq, u8 cmd)
844{
845 struct sk_buff *skb;
846 int err;
847
848 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
849 if (skb == NULL)
850 return ERR_PTR(-ENOBUFS);
851
852 err = ctrl_fill_info(family, portid, seq, 0, skb, cmd);
853 if (err < 0) {
854 nlmsg_free(skb);
855 return ERR_PTR(err);
856 }
857
858 return skb;
859}
860
861static struct sk_buff *
862ctrl_build_mcgrp_msg(struct genl_family *family,
863 const struct genl_multicast_group *grp,
864 int grp_id, u32 portid, int seq, u8 cmd)
865{
866 struct sk_buff *skb;
867 int err;
868
869 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
870 if (skb == NULL)
871 return ERR_PTR(-ENOBUFS);
872
873 err = ctrl_fill_mcgrp_info(family, grp, grp_id, portid,
874 seq, 0, skb, cmd);
875 if (err < 0) {
876 nlmsg_free(skb);
877 return ERR_PTR(err);
878 }
879
880 return skb;
881}
882
883static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
884 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 },
885 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
886 .len = GENL_NAMSIZ - 1 },
887};
888
889static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
890{
891 struct sk_buff *msg;
892 struct genl_family *res = NULL;
893 int err = -EINVAL;
894
895 if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
896 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
897 res = genl_family_find_byid(id);
898 err = -ENOENT;
899 }
900
901 if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
902 char *name;
903
904 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
905 res = genl_family_find_byname(name);
906#ifdef CONFIG_MODULES
907 if (res == NULL) {
908 genl_unlock();
909 up_read(&cb_lock);
910 request_module("net-pf-%d-proto-%d-family-%s",
911 PF_NETLINK, NETLINK_GENERIC, name);
912 down_read(&cb_lock);
913 genl_lock();
914 res = genl_family_find_byname(name);
915 }
916#endif
917 err = -ENOENT;
918 }
919
920 if (res == NULL)
921 return err;
922
923 if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) {
924 /* family doesn't exist here */
925 return -ENOENT;
926 }
927
928 msg = ctrl_build_family_msg(res, info->snd_portid, info->snd_seq,
929 CTRL_CMD_NEWFAMILY);
930 if (IS_ERR(msg))
931 return PTR_ERR(msg);
932
933 return genlmsg_reply(msg, info);
934}
935
936static int genl_ctrl_event(int event, struct genl_family *family,
937 const struct genl_multicast_group *grp,
938 int grp_id)
939{
940 struct sk_buff *msg;
941
942 /* genl is still initialising */
943 if (!init_net.genl_sock)
944 return 0;
945
946 switch (event) {
947 case CTRL_CMD_NEWFAMILY:
948 case CTRL_CMD_DELFAMILY:
949 WARN_ON(grp);
950 msg = ctrl_build_family_msg(family, 0, 0, event);
951 break;
952 case CTRL_CMD_NEWMCAST_GRP:
953 case CTRL_CMD_DELMCAST_GRP:
954 BUG_ON(!grp);
955 msg = ctrl_build_mcgrp_msg(family, grp, grp_id, 0, 0, event);
956 break;
957 default:
958 return -EINVAL;
959 }
960
961 if (IS_ERR(msg))
962 return PTR_ERR(msg);
963
964 if (!family->netnsok) {
965 genlmsg_multicast_netns(&genl_ctrl, &init_net, msg, 0,
966 0, GFP_KERNEL);
967 } else {
968 rcu_read_lock();
969 genlmsg_multicast_allns(&genl_ctrl, msg, 0,
970 0, GFP_ATOMIC);
971 rcu_read_unlock();
972 }
973
974 return 0;
975}
976
977static struct genl_ops genl_ctrl_ops[] = {
978 {
979 .cmd = CTRL_CMD_GETFAMILY,
980 .doit = ctrl_getfamily,
981 .dumpit = ctrl_dumpfamily,
982 .policy = ctrl_policy,
983 },
984};
985
986static struct genl_multicast_group genl_ctrl_groups[] = {
987 { .name = "notify", },
988};
989
990static int __net_init genl_pernet_init(struct net *net)
991{
992 struct netlink_kernel_cfg cfg = {
993 .input = genl_rcv,
994 .flags = NL_CFG_F_NONROOT_RECV,
995 };
996
997 /* we'll bump the group number right afterwards */
998 net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg);
999
1000 if (!net->genl_sock && net_eq(net, &init_net))
1001 panic("GENL: Cannot initialize generic netlink\n");
1002
1003 if (!net->genl_sock)
1004 return -ENOMEM;
1005
1006 return 0;
1007}
1008
1009static void __net_exit genl_pernet_exit(struct net *net)
1010{
1011 netlink_kernel_release(net->genl_sock);
1012 net->genl_sock = NULL;
1013}
1014
1015static struct pernet_operations genl_pernet_ops = {
1016 .init = genl_pernet_init,
1017 .exit = genl_pernet_exit,
1018};
1019
1020static int __init genl_init(void)
1021{
1022 int i, err;
1023
1024 for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
1025 INIT_LIST_HEAD(&family_ht[i]);
1026
1027 err = genl_register_family_with_ops_groups(&genl_ctrl, genl_ctrl_ops,
1028 genl_ctrl_groups);
1029 if (err < 0)
1030 goto problem;
1031
1032 err = register_pernet_subsys(&genl_pernet_ops);
1033 if (err)
1034 goto problem;
1035
1036 return 0;
1037
1038problem:
1039 panic("GENL: Cannot register controller: %d\n", err);
1040}
1041
1042subsys_initcall(genl_init);
1043
1044static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
1045 gfp_t flags)
1046{
1047 struct sk_buff *tmp;
1048 struct net *net, *prev = NULL;
1049 int err;
1050
1051 for_each_net_rcu(net) {
1052 if (prev) {
1053 tmp = skb_clone(skb, flags);
1054 if (!tmp) {
1055 err = -ENOMEM;
1056 goto error;
1057 }
1058 err = nlmsg_multicast(prev->genl_sock, tmp,
1059 portid, group, flags);
1060 if (err)
1061 goto error;
1062 }
1063
1064 prev = net;
1065 }
1066
1067 return nlmsg_multicast(prev->genl_sock, skb, portid, group, flags);
1068 error:
1069 kfree_skb(skb);
1070 return err;
1071}
1072
1073int genlmsg_multicast_allns(struct genl_family *family, struct sk_buff *skb,
1074 u32 portid, unsigned int group, gfp_t flags)
1075{
1076 if (WARN_ON_ONCE(group >= family->n_mcgrps))
1077 return -EINVAL;
1078 group = family->mcgrp_offset + group;
1079 return genlmsg_mcast(skb, portid, group, flags);
1080}
1081EXPORT_SYMBOL(genlmsg_multicast_allns);
1082
1083void genl_notify(struct genl_family *family,
1084 struct sk_buff *skb, struct net *net, u32 portid, u32 group,
1085 struct nlmsghdr *nlh, gfp_t flags)
1086{
1087 struct sock *sk = net->genl_sock;
1088 int report = 0;
1089
1090 if (nlh)
1091 report = nlmsg_report(nlh);
1092
1093 if (WARN_ON_ONCE(group >= family->n_mcgrps))
1094 return;
1095 group = family->mcgrp_offset + group;
1096 nlmsg_notify(sk, skb, portid, group, report, flags);
1097}
1098EXPORT_SYMBOL(genl_notify);