WIP FPC-III support
[linux/fpc-iii.git] / net / netlink / genetlink.c
blobc992424e4d632d9f656f603d8ad27639eefb8fba
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * NETLINK Generic Netlink Family
5 * Authors: Jamal Hadi Salim
6 * Thomas Graf <tgraf@suug.ch>
7 * Johannes Berg <johannes@sipsolutions.net>
8 */
10 #include <linux/module.h>
11 #include <linux/kernel.h>
12 #include <linux/slab.h>
13 #include <linux/errno.h>
14 #include <linux/types.h>
15 #include <linux/socket.h>
16 #include <linux/string.h>
17 #include <linux/skbuff.h>
18 #include <linux/mutex.h>
19 #include <linux/bitmap.h>
20 #include <linux/rwsem.h>
21 #include <linux/idr.h>
22 #include <net/sock.h>
23 #include <net/genetlink.h>
25 static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */
26 static DECLARE_RWSEM(cb_lock);
28 atomic_t genl_sk_destructing_cnt = ATOMIC_INIT(0);
29 DECLARE_WAIT_QUEUE_HEAD(genl_sk_destructing_waitq);
31 void genl_lock(void)
33 mutex_lock(&genl_mutex);
35 EXPORT_SYMBOL(genl_lock);
37 void genl_unlock(void)
39 mutex_unlock(&genl_mutex);
41 EXPORT_SYMBOL(genl_unlock);
43 #ifdef CONFIG_LOCKDEP
44 bool lockdep_genl_is_held(void)
46 return lockdep_is_held(&genl_mutex);
48 EXPORT_SYMBOL(lockdep_genl_is_held);
49 #endif
51 static void genl_lock_all(void)
53 down_write(&cb_lock);
54 genl_lock();
57 static void genl_unlock_all(void)
59 genl_unlock();
60 up_write(&cb_lock);
63 static DEFINE_IDR(genl_fam_idr);
66 * Bitmap of multicast groups that are currently in use.
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?)
83 static unsigned long mc_group_start = 0x3 | BIT(GENL_ID_CTRL) |
84 BIT(GENL_ID_VFS_DQUOT) |
85 BIT(GENL_ID_PMCRAID);
86 static unsigned long *mc_groups = &mc_group_start;
87 static unsigned long mc_groups_longs = 1;
89 static int genl_ctrl_event(int event, const struct genl_family *family,
90 const struct genl_multicast_group *grp,
91 int grp_id);
93 static const struct genl_family *genl_family_find_byid(unsigned int id)
95 return idr_find(&genl_fam_idr, id);
98 static const struct genl_family *genl_family_find_byname(char *name)
100 const struct genl_family *family;
101 unsigned int id;
103 idr_for_each_entry(&genl_fam_idr, family, id)
104 if (strcmp(family->name, name) == 0)
105 return family;
107 return NULL;
110 static int genl_get_cmd_cnt(const struct genl_family *family)
112 return family->n_ops + family->n_small_ops;
115 static void genl_op_from_full(const struct genl_family *family,
116 unsigned int i, struct genl_ops *op)
118 *op = family->ops[i];
120 if (!op->maxattr)
121 op->maxattr = family->maxattr;
122 if (!op->policy)
123 op->policy = family->policy;
126 static int genl_get_cmd_full(u32 cmd, const struct genl_family *family,
127 struct genl_ops *op)
129 int i;
131 for (i = 0; i < family->n_ops; i++)
132 if (family->ops[i].cmd == cmd) {
133 genl_op_from_full(family, i, op);
134 return 0;
137 return -ENOENT;
140 static void genl_op_from_small(const struct genl_family *family,
141 unsigned int i, struct genl_ops *op)
143 memset(op, 0, sizeof(*op));
144 op->doit = family->small_ops[i].doit;
145 op->dumpit = family->small_ops[i].dumpit;
146 op->cmd = family->small_ops[i].cmd;
147 op->internal_flags = family->small_ops[i].internal_flags;
148 op->flags = family->small_ops[i].flags;
149 op->validate = family->small_ops[i].validate;
151 op->maxattr = family->maxattr;
152 op->policy = family->policy;
155 static int genl_get_cmd_small(u32 cmd, const struct genl_family *family,
156 struct genl_ops *op)
158 int i;
160 for (i = 0; i < family->n_small_ops; i++)
161 if (family->small_ops[i].cmd == cmd) {
162 genl_op_from_small(family, i, op);
163 return 0;
166 return -ENOENT;
169 static int genl_get_cmd(u32 cmd, const struct genl_family *family,
170 struct genl_ops *op)
172 if (!genl_get_cmd_full(cmd, family, op))
173 return 0;
174 return genl_get_cmd_small(cmd, family, op);
177 static void genl_get_cmd_by_index(unsigned int i,
178 const struct genl_family *family,
179 struct genl_ops *op)
181 if (i < family->n_ops)
182 genl_op_from_full(family, i, op);
183 else if (i < family->n_ops + family->n_small_ops)
184 genl_op_from_small(family, i - family->n_ops, op);
185 else
186 WARN_ON_ONCE(1);
189 static int genl_allocate_reserve_groups(int n_groups, int *first_id)
191 unsigned long *new_groups;
192 int start = 0;
193 int i;
194 int id;
195 bool fits;
197 do {
198 if (start == 0)
199 id = find_first_zero_bit(mc_groups,
200 mc_groups_longs *
201 BITS_PER_LONG);
202 else
203 id = find_next_zero_bit(mc_groups,
204 mc_groups_longs * BITS_PER_LONG,
205 start);
207 fits = true;
208 for (i = id;
209 i < min_t(int, id + n_groups,
210 mc_groups_longs * BITS_PER_LONG);
211 i++) {
212 if (test_bit(i, mc_groups)) {
213 start = i;
214 fits = false;
215 break;
219 if (id + n_groups > mc_groups_longs * BITS_PER_LONG) {
220 unsigned long new_longs = mc_groups_longs +
221 BITS_TO_LONGS(n_groups);
222 size_t nlen = new_longs * sizeof(unsigned long);
224 if (mc_groups == &mc_group_start) {
225 new_groups = kzalloc(nlen, GFP_KERNEL);
226 if (!new_groups)
227 return -ENOMEM;
228 mc_groups = new_groups;
229 *mc_groups = mc_group_start;
230 } else {
231 new_groups = krealloc(mc_groups, nlen,
232 GFP_KERNEL);
233 if (!new_groups)
234 return -ENOMEM;
235 mc_groups = new_groups;
236 for (i = 0; i < BITS_TO_LONGS(n_groups); i++)
237 mc_groups[mc_groups_longs + i] = 0;
239 mc_groups_longs = new_longs;
241 } while (!fits);
243 for (i = id; i < id + n_groups; i++)
244 set_bit(i, mc_groups);
245 *first_id = id;
246 return 0;
249 static struct genl_family genl_ctrl;
251 static int genl_validate_assign_mc_groups(struct genl_family *family)
253 int first_id;
254 int n_groups = family->n_mcgrps;
255 int err = 0, i;
256 bool groups_allocated = false;
258 if (!n_groups)
259 return 0;
261 for (i = 0; i < n_groups; i++) {
262 const struct genl_multicast_group *grp = &family->mcgrps[i];
264 if (WARN_ON(grp->name[0] == '\0'))
265 return -EINVAL;
266 if (WARN_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL))
267 return -EINVAL;
270 /* special-case our own group and hacks */
271 if (family == &genl_ctrl) {
272 first_id = GENL_ID_CTRL;
273 BUG_ON(n_groups != 1);
274 } else if (strcmp(family->name, "NET_DM") == 0) {
275 first_id = 1;
276 BUG_ON(n_groups != 1);
277 } else if (family->id == GENL_ID_VFS_DQUOT) {
278 first_id = GENL_ID_VFS_DQUOT;
279 BUG_ON(n_groups != 1);
280 } else if (family->id == GENL_ID_PMCRAID) {
281 first_id = GENL_ID_PMCRAID;
282 BUG_ON(n_groups != 1);
283 } else {
284 groups_allocated = true;
285 err = genl_allocate_reserve_groups(n_groups, &first_id);
286 if (err)
287 return err;
290 family->mcgrp_offset = first_id;
292 /* if still initializing, can't and don't need to realloc bitmaps */
293 if (!init_net.genl_sock)
294 return 0;
296 if (family->netnsok) {
297 struct net *net;
299 netlink_table_grab();
300 rcu_read_lock();
301 for_each_net_rcu(net) {
302 err = __netlink_change_ngroups(net->genl_sock,
303 mc_groups_longs * BITS_PER_LONG);
304 if (err) {
306 * No need to roll back, can only fail if
307 * memory allocation fails and then the
308 * number of _possible_ groups has been
309 * increased on some sockets which is ok.
311 break;
314 rcu_read_unlock();
315 netlink_table_ungrab();
316 } else {
317 err = netlink_change_ngroups(init_net.genl_sock,
318 mc_groups_longs * BITS_PER_LONG);
321 if (groups_allocated && err) {
322 for (i = 0; i < family->n_mcgrps; i++)
323 clear_bit(family->mcgrp_offset + i, mc_groups);
326 return err;
329 static void genl_unregister_mc_groups(const struct genl_family *family)
331 struct net *net;
332 int i;
334 netlink_table_grab();
335 rcu_read_lock();
336 for_each_net_rcu(net) {
337 for (i = 0; i < family->n_mcgrps; i++)
338 __netlink_clear_multicast_users(
339 net->genl_sock, family->mcgrp_offset + i);
341 rcu_read_unlock();
342 netlink_table_ungrab();
344 for (i = 0; i < family->n_mcgrps; i++) {
345 int grp_id = family->mcgrp_offset + i;
347 if (grp_id != 1)
348 clear_bit(grp_id, mc_groups);
349 genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, family,
350 &family->mcgrps[i], grp_id);
354 static int genl_validate_ops(const struct genl_family *family)
356 int i, j;
358 if (WARN_ON(family->n_ops && !family->ops) ||
359 WARN_ON(family->n_small_ops && !family->small_ops))
360 return -EINVAL;
362 for (i = 0; i < genl_get_cmd_cnt(family); i++) {
363 struct genl_ops op;
365 genl_get_cmd_by_index(i, family, &op);
366 if (op.dumpit == NULL && op.doit == NULL)
367 return -EINVAL;
368 for (j = i + 1; j < genl_get_cmd_cnt(family); j++) {
369 struct genl_ops op2;
371 genl_get_cmd_by_index(j, family, &op2);
372 if (op.cmd == op2.cmd)
373 return -EINVAL;
377 return 0;
381 * genl_register_family - register a generic netlink family
382 * @family: generic netlink family
384 * Registers the specified family after validating it first. Only one
385 * family may be registered with the same family name or identifier.
387 * The family's ops, multicast groups and module pointer must already
388 * be assigned.
390 * Return 0 on success or a negative error code.
392 int genl_register_family(struct genl_family *family)
394 int err, i;
395 int start = GENL_START_ALLOC, end = GENL_MAX_ID;
397 err = genl_validate_ops(family);
398 if (err)
399 return err;
401 genl_lock_all();
403 if (genl_family_find_byname(family->name)) {
404 err = -EEXIST;
405 goto errout_locked;
409 * Sadly, a few cases need to be special-cased
410 * due to them having previously abused the API
411 * and having used their family ID also as their
412 * multicast group ID, so we use reserved IDs
413 * for both to be sure we can do that mapping.
415 if (family == &genl_ctrl) {
416 /* and this needs to be special for initial family lookups */
417 start = end = GENL_ID_CTRL;
418 } else if (strcmp(family->name, "pmcraid") == 0) {
419 start = end = GENL_ID_PMCRAID;
420 } else if (strcmp(family->name, "VFS_DQUOT") == 0) {
421 start = end = GENL_ID_VFS_DQUOT;
424 family->id = idr_alloc_cyclic(&genl_fam_idr, family,
425 start, end + 1, GFP_KERNEL);
426 if (family->id < 0) {
427 err = family->id;
428 goto errout_locked;
431 err = genl_validate_assign_mc_groups(family);
432 if (err)
433 goto errout_remove;
435 genl_unlock_all();
437 /* send all events */
438 genl_ctrl_event(CTRL_CMD_NEWFAMILY, family, NULL, 0);
439 for (i = 0; i < family->n_mcgrps; i++)
440 genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, family,
441 &family->mcgrps[i], family->mcgrp_offset + i);
443 return 0;
445 errout_remove:
446 idr_remove(&genl_fam_idr, family->id);
447 errout_locked:
448 genl_unlock_all();
449 return err;
451 EXPORT_SYMBOL(genl_register_family);
454 * genl_unregister_family - unregister generic netlink family
455 * @family: generic netlink family
457 * Unregisters the specified family.
459 * Returns 0 on success or a negative error code.
461 int genl_unregister_family(const struct genl_family *family)
463 genl_lock_all();
465 if (!genl_family_find_byid(family->id)) {
466 genl_unlock_all();
467 return -ENOENT;
470 genl_unregister_mc_groups(family);
472 idr_remove(&genl_fam_idr, family->id);
474 up_write(&cb_lock);
475 wait_event(genl_sk_destructing_waitq,
476 atomic_read(&genl_sk_destructing_cnt) == 0);
477 genl_unlock();
479 genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 0);
481 return 0;
483 EXPORT_SYMBOL(genl_unregister_family);
486 * genlmsg_put - Add generic netlink header to netlink message
487 * @skb: socket buffer holding the message
488 * @portid: netlink portid the message is addressed to
489 * @seq: sequence number (usually the one of the sender)
490 * @family: generic netlink family
491 * @flags: netlink message flags
492 * @cmd: generic netlink command
494 * Returns pointer to user specific header
496 void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
497 const struct genl_family *family, int flags, u8 cmd)
499 struct nlmsghdr *nlh;
500 struct genlmsghdr *hdr;
502 nlh = nlmsg_put(skb, portid, seq, family->id, GENL_HDRLEN +
503 family->hdrsize, flags);
504 if (nlh == NULL)
505 return NULL;
507 hdr = nlmsg_data(nlh);
508 hdr->cmd = cmd;
509 hdr->version = family->version;
510 hdr->reserved = 0;
512 return (char *) hdr + GENL_HDRLEN;
514 EXPORT_SYMBOL(genlmsg_put);
516 static struct genl_dumpit_info *genl_dumpit_info_alloc(void)
518 return kmalloc(sizeof(struct genl_dumpit_info), GFP_KERNEL);
521 static void genl_dumpit_info_free(const struct genl_dumpit_info *info)
523 kfree(info);
526 static struct nlattr **
527 genl_family_rcv_msg_attrs_parse(const struct genl_family *family,
528 struct nlmsghdr *nlh,
529 struct netlink_ext_ack *extack,
530 const struct genl_ops *ops,
531 int hdrlen,
532 enum genl_validate_flags no_strict_flag)
534 enum netlink_validation validate = ops->validate & no_strict_flag ?
535 NL_VALIDATE_LIBERAL :
536 NL_VALIDATE_STRICT;
537 struct nlattr **attrbuf;
538 int err;
540 if (!ops->maxattr)
541 return NULL;
543 attrbuf = kmalloc_array(ops->maxattr + 1,
544 sizeof(struct nlattr *), GFP_KERNEL);
545 if (!attrbuf)
546 return ERR_PTR(-ENOMEM);
548 err = __nlmsg_parse(nlh, hdrlen, attrbuf, ops->maxattr, ops->policy,
549 validate, extack);
550 if (err) {
551 kfree(attrbuf);
552 return ERR_PTR(err);
554 return attrbuf;
557 static void genl_family_rcv_msg_attrs_free(struct nlattr **attrbuf)
559 kfree(attrbuf);
562 struct genl_start_context {
563 const struct genl_family *family;
564 struct nlmsghdr *nlh;
565 struct netlink_ext_ack *extack;
566 const struct genl_ops *ops;
567 int hdrlen;
570 static int genl_start(struct netlink_callback *cb)
572 struct genl_start_context *ctx = cb->data;
573 const struct genl_ops *ops = ctx->ops;
574 struct genl_dumpit_info *info;
575 struct nlattr **attrs = NULL;
576 int rc = 0;
578 if (ops->validate & GENL_DONT_VALIDATE_DUMP)
579 goto no_attrs;
581 if (ctx->nlh->nlmsg_len < nlmsg_msg_size(ctx->hdrlen))
582 return -EINVAL;
584 attrs = genl_family_rcv_msg_attrs_parse(ctx->family, ctx->nlh, ctx->extack,
585 ops, ctx->hdrlen,
586 GENL_DONT_VALIDATE_DUMP_STRICT);
587 if (IS_ERR(attrs))
588 return PTR_ERR(attrs);
590 no_attrs:
591 info = genl_dumpit_info_alloc();
592 if (!info) {
593 genl_family_rcv_msg_attrs_free(attrs);
594 return -ENOMEM;
596 info->family = ctx->family;
597 info->op = *ops;
598 info->attrs = attrs;
600 cb->data = info;
601 if (ops->start) {
602 if (!ctx->family->parallel_ops)
603 genl_lock();
604 rc = ops->start(cb);
605 if (!ctx->family->parallel_ops)
606 genl_unlock();
609 if (rc) {
610 genl_family_rcv_msg_attrs_free(info->attrs);
611 genl_dumpit_info_free(info);
612 cb->data = NULL;
614 return rc;
617 static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
619 const struct genl_ops *ops = &genl_dumpit_info(cb)->op;
620 int rc;
622 genl_lock();
623 rc = ops->dumpit(skb, cb);
624 genl_unlock();
625 return rc;
628 static int genl_lock_done(struct netlink_callback *cb)
630 const struct genl_dumpit_info *info = genl_dumpit_info(cb);
631 const struct genl_ops *ops = &info->op;
632 int rc = 0;
634 if (ops->done) {
635 genl_lock();
636 rc = ops->done(cb);
637 genl_unlock();
639 genl_family_rcv_msg_attrs_free(info->attrs);
640 genl_dumpit_info_free(info);
641 return rc;
644 static int genl_parallel_done(struct netlink_callback *cb)
646 const struct genl_dumpit_info *info = genl_dumpit_info(cb);
647 const struct genl_ops *ops = &info->op;
648 int rc = 0;
650 if (ops->done)
651 rc = ops->done(cb);
652 genl_family_rcv_msg_attrs_free(info->attrs);
653 genl_dumpit_info_free(info);
654 return rc;
657 static int genl_family_rcv_msg_dumpit(const struct genl_family *family,
658 struct sk_buff *skb,
659 struct nlmsghdr *nlh,
660 struct netlink_ext_ack *extack,
661 const struct genl_ops *ops,
662 int hdrlen, struct net *net)
664 struct genl_start_context ctx;
665 int err;
667 if (!ops->dumpit)
668 return -EOPNOTSUPP;
670 ctx.family = family;
671 ctx.nlh = nlh;
672 ctx.extack = extack;
673 ctx.ops = ops;
674 ctx.hdrlen = hdrlen;
676 if (!family->parallel_ops) {
677 struct netlink_dump_control c = {
678 .module = family->module,
679 .data = &ctx,
680 .start = genl_start,
681 .dump = genl_lock_dumpit,
682 .done = genl_lock_done,
685 genl_unlock();
686 err = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
687 genl_lock();
688 } else {
689 struct netlink_dump_control c = {
690 .module = family->module,
691 .data = &ctx,
692 .start = genl_start,
693 .dump = ops->dumpit,
694 .done = genl_parallel_done,
697 err = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
700 return err;
703 static int genl_family_rcv_msg_doit(const struct genl_family *family,
704 struct sk_buff *skb,
705 struct nlmsghdr *nlh,
706 struct netlink_ext_ack *extack,
707 const struct genl_ops *ops,
708 int hdrlen, struct net *net)
710 struct nlattr **attrbuf;
711 struct genl_info info;
712 int err;
714 if (!ops->doit)
715 return -EOPNOTSUPP;
717 attrbuf = genl_family_rcv_msg_attrs_parse(family, nlh, extack,
718 ops, hdrlen,
719 GENL_DONT_VALIDATE_STRICT);
720 if (IS_ERR(attrbuf))
721 return PTR_ERR(attrbuf);
723 info.snd_seq = nlh->nlmsg_seq;
724 info.snd_portid = NETLINK_CB(skb).portid;
725 info.nlhdr = nlh;
726 info.genlhdr = nlmsg_data(nlh);
727 info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
728 info.attrs = attrbuf;
729 info.extack = extack;
730 genl_info_net_set(&info, net);
731 memset(&info.user_ptr, 0, sizeof(info.user_ptr));
733 if (family->pre_doit) {
734 err = family->pre_doit(ops, skb, &info);
735 if (err)
736 goto out;
739 err = ops->doit(skb, &info);
741 if (family->post_doit)
742 family->post_doit(ops, skb, &info);
744 out:
745 genl_family_rcv_msg_attrs_free(attrbuf);
747 return err;
750 static int genl_family_rcv_msg(const struct genl_family *family,
751 struct sk_buff *skb,
752 struct nlmsghdr *nlh,
753 struct netlink_ext_ack *extack)
755 struct net *net = sock_net(skb->sk);
756 struct genlmsghdr *hdr = nlmsg_data(nlh);
757 struct genl_ops op;
758 int hdrlen;
760 /* this family doesn't exist in this netns */
761 if (!family->netnsok && !net_eq(net, &init_net))
762 return -ENOENT;
764 hdrlen = GENL_HDRLEN + family->hdrsize;
765 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
766 return -EINVAL;
768 if (genl_get_cmd(hdr->cmd, family, &op))
769 return -EOPNOTSUPP;
771 if ((op.flags & GENL_ADMIN_PERM) &&
772 !netlink_capable(skb, CAP_NET_ADMIN))
773 return -EPERM;
775 if ((op.flags & GENL_UNS_ADMIN_PERM) &&
776 !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
777 return -EPERM;
779 if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP)
780 return genl_family_rcv_msg_dumpit(family, skb, nlh, extack,
781 &op, hdrlen, net);
782 else
783 return genl_family_rcv_msg_doit(family, skb, nlh, extack,
784 &op, hdrlen, net);
787 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
788 struct netlink_ext_ack *extack)
790 const struct genl_family *family;
791 int err;
793 family = genl_family_find_byid(nlh->nlmsg_type);
794 if (family == NULL)
795 return -ENOENT;
797 if (!family->parallel_ops)
798 genl_lock();
800 err = genl_family_rcv_msg(family, skb, nlh, extack);
802 if (!family->parallel_ops)
803 genl_unlock();
805 return err;
808 static void genl_rcv(struct sk_buff *skb)
810 down_read(&cb_lock);
811 netlink_rcv_skb(skb, &genl_rcv_msg);
812 up_read(&cb_lock);
815 /**************************************************************************
816 * Controller
817 **************************************************************************/
819 static struct genl_family genl_ctrl;
821 static int ctrl_fill_info(const struct genl_family *family, u32 portid, u32 seq,
822 u32 flags, struct sk_buff *skb, u8 cmd)
824 void *hdr;
826 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
827 if (hdr == NULL)
828 return -1;
830 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
831 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) ||
832 nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) ||
833 nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) ||
834 nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr))
835 goto nla_put_failure;
837 if (genl_get_cmd_cnt(family)) {
838 struct nlattr *nla_ops;
839 int i;
841 nla_ops = nla_nest_start_noflag(skb, CTRL_ATTR_OPS);
842 if (nla_ops == NULL)
843 goto nla_put_failure;
845 for (i = 0; i < genl_get_cmd_cnt(family); i++) {
846 struct nlattr *nest;
847 struct genl_ops op;
848 u32 op_flags;
850 genl_get_cmd_by_index(i, family, &op);
851 op_flags = op.flags;
852 if (op.dumpit)
853 op_flags |= GENL_CMD_CAP_DUMP;
854 if (op.doit)
855 op_flags |= GENL_CMD_CAP_DO;
856 if (op.policy)
857 op_flags |= GENL_CMD_CAP_HASPOL;
859 nest = nla_nest_start_noflag(skb, i + 1);
860 if (nest == NULL)
861 goto nla_put_failure;
863 if (nla_put_u32(skb, CTRL_ATTR_OP_ID, op.cmd) ||
864 nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, op_flags))
865 goto nla_put_failure;
867 nla_nest_end(skb, nest);
870 nla_nest_end(skb, nla_ops);
873 if (family->n_mcgrps) {
874 struct nlattr *nla_grps;
875 int i;
877 nla_grps = nla_nest_start_noflag(skb, CTRL_ATTR_MCAST_GROUPS);
878 if (nla_grps == NULL)
879 goto nla_put_failure;
881 for (i = 0; i < family->n_mcgrps; i++) {
882 struct nlattr *nest;
883 const struct genl_multicast_group *grp;
885 grp = &family->mcgrps[i];
887 nest = nla_nest_start_noflag(skb, i + 1);
888 if (nest == NULL)
889 goto nla_put_failure;
891 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID,
892 family->mcgrp_offset + i) ||
893 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
894 grp->name))
895 goto nla_put_failure;
897 nla_nest_end(skb, nest);
899 nla_nest_end(skb, nla_grps);
902 genlmsg_end(skb, hdr);
903 return 0;
905 nla_put_failure:
906 genlmsg_cancel(skb, hdr);
907 return -EMSGSIZE;
910 static int ctrl_fill_mcgrp_info(const struct genl_family *family,
911 const struct genl_multicast_group *grp,
912 int grp_id, u32 portid, u32 seq, u32 flags,
913 struct sk_buff *skb, u8 cmd)
915 void *hdr;
916 struct nlattr *nla_grps;
917 struct nlattr *nest;
919 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
920 if (hdr == NULL)
921 return -1;
923 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
924 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id))
925 goto nla_put_failure;
927 nla_grps = nla_nest_start_noflag(skb, CTRL_ATTR_MCAST_GROUPS);
928 if (nla_grps == NULL)
929 goto nla_put_failure;
931 nest = nla_nest_start_noflag(skb, 1);
932 if (nest == NULL)
933 goto nla_put_failure;
935 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp_id) ||
936 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
937 grp->name))
938 goto nla_put_failure;
940 nla_nest_end(skb, nest);
941 nla_nest_end(skb, nla_grps);
943 genlmsg_end(skb, hdr);
944 return 0;
946 nla_put_failure:
947 genlmsg_cancel(skb, hdr);
948 return -EMSGSIZE;
951 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
953 int n = 0;
954 struct genl_family *rt;
955 struct net *net = sock_net(skb->sk);
956 int fams_to_skip = cb->args[0];
957 unsigned int id;
959 idr_for_each_entry(&genl_fam_idr, rt, id) {
960 if (!rt->netnsok && !net_eq(net, &init_net))
961 continue;
963 if (n++ < fams_to_skip)
964 continue;
966 if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid,
967 cb->nlh->nlmsg_seq, NLM_F_MULTI,
968 skb, CTRL_CMD_NEWFAMILY) < 0) {
969 n--;
970 break;
974 cb->args[0] = n;
975 return skb->len;
978 static struct sk_buff *ctrl_build_family_msg(const struct genl_family *family,
979 u32 portid, int seq, u8 cmd)
981 struct sk_buff *skb;
982 int err;
984 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
985 if (skb == NULL)
986 return ERR_PTR(-ENOBUFS);
988 err = ctrl_fill_info(family, portid, seq, 0, skb, cmd);
989 if (err < 0) {
990 nlmsg_free(skb);
991 return ERR_PTR(err);
994 return skb;
997 static struct sk_buff *
998 ctrl_build_mcgrp_msg(const struct genl_family *family,
999 const struct genl_multicast_group *grp,
1000 int grp_id, u32 portid, int seq, u8 cmd)
1002 struct sk_buff *skb;
1003 int err;
1005 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1006 if (skb == NULL)
1007 return ERR_PTR(-ENOBUFS);
1009 err = ctrl_fill_mcgrp_info(family, grp, grp_id, portid,
1010 seq, 0, skb, cmd);
1011 if (err < 0) {
1012 nlmsg_free(skb);
1013 return ERR_PTR(err);
1016 return skb;
1019 static const struct nla_policy ctrl_policy_family[] = {
1020 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 },
1021 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
1022 .len = GENL_NAMSIZ - 1 },
1025 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
1027 struct sk_buff *msg;
1028 const struct genl_family *res = NULL;
1029 int err = -EINVAL;
1031 if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
1032 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
1033 res = genl_family_find_byid(id);
1034 err = -ENOENT;
1037 if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
1038 char *name;
1040 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
1041 res = genl_family_find_byname(name);
1042 #ifdef CONFIG_MODULES
1043 if (res == NULL) {
1044 genl_unlock();
1045 up_read(&cb_lock);
1046 request_module("net-pf-%d-proto-%d-family-%s",
1047 PF_NETLINK, NETLINK_GENERIC, name);
1048 down_read(&cb_lock);
1049 genl_lock();
1050 res = genl_family_find_byname(name);
1052 #endif
1053 err = -ENOENT;
1056 if (res == NULL)
1057 return err;
1059 if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) {
1060 /* family doesn't exist here */
1061 return -ENOENT;
1064 msg = ctrl_build_family_msg(res, info->snd_portid, info->snd_seq,
1065 CTRL_CMD_NEWFAMILY);
1066 if (IS_ERR(msg))
1067 return PTR_ERR(msg);
1069 return genlmsg_reply(msg, info);
1072 static int genl_ctrl_event(int event, const struct genl_family *family,
1073 const struct genl_multicast_group *grp,
1074 int grp_id)
1076 struct sk_buff *msg;
1078 /* genl is still initialising */
1079 if (!init_net.genl_sock)
1080 return 0;
1082 switch (event) {
1083 case CTRL_CMD_NEWFAMILY:
1084 case CTRL_CMD_DELFAMILY:
1085 WARN_ON(grp);
1086 msg = ctrl_build_family_msg(family, 0, 0, event);
1087 break;
1088 case CTRL_CMD_NEWMCAST_GRP:
1089 case CTRL_CMD_DELMCAST_GRP:
1090 BUG_ON(!grp);
1091 msg = ctrl_build_mcgrp_msg(family, grp, grp_id, 0, 0, event);
1092 break;
1093 default:
1094 return -EINVAL;
1097 if (IS_ERR(msg))
1098 return PTR_ERR(msg);
1100 if (!family->netnsok) {
1101 genlmsg_multicast_netns(&genl_ctrl, &init_net, msg, 0,
1102 0, GFP_KERNEL);
1103 } else {
1104 rcu_read_lock();
1105 genlmsg_multicast_allns(&genl_ctrl, msg, 0,
1106 0, GFP_ATOMIC);
1107 rcu_read_unlock();
1110 return 0;
1113 struct ctrl_dump_policy_ctx {
1114 struct netlink_policy_dump_state *state;
1115 const struct genl_family *rt;
1116 unsigned int opidx;
1117 u32 op;
1118 u16 fam_id;
1119 u8 policies:1,
1120 single_op:1;
1123 static const struct nla_policy ctrl_policy_policy[] = {
1124 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 },
1125 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
1126 .len = GENL_NAMSIZ - 1 },
1127 [CTRL_ATTR_OP] = { .type = NLA_U32 },
1130 static int ctrl_dumppolicy_start(struct netlink_callback *cb)
1132 const struct genl_dumpit_info *info = genl_dumpit_info(cb);
1133 struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
1134 struct nlattr **tb = info->attrs;
1135 const struct genl_family *rt;
1136 struct genl_ops op;
1137 int err, i;
1139 BUILD_BUG_ON(sizeof(*ctx) > sizeof(cb->ctx));
1141 if (!tb[CTRL_ATTR_FAMILY_ID] && !tb[CTRL_ATTR_FAMILY_NAME])
1142 return -EINVAL;
1144 if (tb[CTRL_ATTR_FAMILY_ID]) {
1145 ctx->fam_id = nla_get_u16(tb[CTRL_ATTR_FAMILY_ID]);
1146 } else {
1147 rt = genl_family_find_byname(
1148 nla_data(tb[CTRL_ATTR_FAMILY_NAME]));
1149 if (!rt)
1150 return -ENOENT;
1151 ctx->fam_id = rt->id;
1154 rt = genl_family_find_byid(ctx->fam_id);
1155 if (!rt)
1156 return -ENOENT;
1158 ctx->rt = rt;
1160 if (tb[CTRL_ATTR_OP]) {
1161 ctx->single_op = true;
1162 ctx->op = nla_get_u32(tb[CTRL_ATTR_OP]);
1164 err = genl_get_cmd(ctx->op, rt, &op);
1165 if (err) {
1166 NL_SET_BAD_ATTR(cb->extack, tb[CTRL_ATTR_OP]);
1167 return err;
1170 if (!op.policy)
1171 return -ENODATA;
1173 return netlink_policy_dump_add_policy(&ctx->state, op.policy,
1174 op.maxattr);
1177 for (i = 0; i < genl_get_cmd_cnt(rt); i++) {
1178 genl_get_cmd_by_index(i, rt, &op);
1180 if (op.policy) {
1181 err = netlink_policy_dump_add_policy(&ctx->state,
1182 op.policy,
1183 op.maxattr);
1184 if (err)
1185 return err;
1189 if (!ctx->state)
1190 return -ENODATA;
1191 return 0;
1194 static void *ctrl_dumppolicy_prep(struct sk_buff *skb,
1195 struct netlink_callback *cb)
1197 struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
1198 void *hdr;
1200 hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid,
1201 cb->nlh->nlmsg_seq, &genl_ctrl,
1202 NLM_F_MULTI, CTRL_CMD_GETPOLICY);
1203 if (!hdr)
1204 return NULL;
1206 if (nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, ctx->fam_id))
1207 return NULL;
1209 return hdr;
1212 static int ctrl_dumppolicy_put_op(struct sk_buff *skb,
1213 struct netlink_callback *cb,
1214 struct genl_ops *op)
1216 struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
1217 struct nlattr *nest_pol, *nest_op;
1218 void *hdr;
1219 int idx;
1221 /* skip if we have nothing to show */
1222 if (!op->policy)
1223 return 0;
1224 if (!op->doit &&
1225 (!op->dumpit || op->validate & GENL_DONT_VALIDATE_DUMP))
1226 return 0;
1228 hdr = ctrl_dumppolicy_prep(skb, cb);
1229 if (!hdr)
1230 return -ENOBUFS;
1232 nest_pol = nla_nest_start(skb, CTRL_ATTR_OP_POLICY);
1233 if (!nest_pol)
1234 goto err;
1236 nest_op = nla_nest_start(skb, op->cmd);
1237 if (!nest_op)
1238 goto err;
1240 /* for now both do/dump are always the same */
1241 idx = netlink_policy_dump_get_policy_idx(ctx->state,
1242 op->policy,
1243 op->maxattr);
1245 if (op->doit && nla_put_u32(skb, CTRL_ATTR_POLICY_DO, idx))
1246 goto err;
1248 if (op->dumpit && !(op->validate & GENL_DONT_VALIDATE_DUMP) &&
1249 nla_put_u32(skb, CTRL_ATTR_POLICY_DUMP, idx))
1250 goto err;
1252 nla_nest_end(skb, nest_op);
1253 nla_nest_end(skb, nest_pol);
1254 genlmsg_end(skb, hdr);
1256 return 0;
1257 err:
1258 genlmsg_cancel(skb, hdr);
1259 return -ENOBUFS;
1262 static int ctrl_dumppolicy(struct sk_buff *skb, struct netlink_callback *cb)
1264 struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
1265 void *hdr;
1267 if (!ctx->policies) {
1268 while (ctx->opidx < genl_get_cmd_cnt(ctx->rt)) {
1269 struct genl_ops op;
1271 if (ctx->single_op) {
1272 int err;
1274 err = genl_get_cmd(ctx->op, ctx->rt, &op);
1275 if (WARN_ON(err))
1276 return skb->len;
1278 /* break out of the loop after this one */
1279 ctx->opidx = genl_get_cmd_cnt(ctx->rt);
1280 } else {
1281 genl_get_cmd_by_index(ctx->opidx, ctx->rt, &op);
1284 if (ctrl_dumppolicy_put_op(skb, cb, &op))
1285 return skb->len;
1287 ctx->opidx++;
1290 /* completed with the per-op policy index list */
1291 ctx->policies = true;
1294 while (netlink_policy_dump_loop(ctx->state)) {
1295 struct nlattr *nest;
1297 hdr = ctrl_dumppolicy_prep(skb, cb);
1298 if (!hdr)
1299 goto nla_put_failure;
1301 nest = nla_nest_start(skb, CTRL_ATTR_POLICY);
1302 if (!nest)
1303 goto nla_put_failure;
1305 if (netlink_policy_dump_write(skb, ctx->state))
1306 goto nla_put_failure;
1308 nla_nest_end(skb, nest);
1310 genlmsg_end(skb, hdr);
1313 return skb->len;
1315 nla_put_failure:
1316 genlmsg_cancel(skb, hdr);
1317 return skb->len;
1320 static int ctrl_dumppolicy_done(struct netlink_callback *cb)
1322 struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
1324 netlink_policy_dump_free(ctx->state);
1325 return 0;
1328 static const struct genl_ops genl_ctrl_ops[] = {
1330 .cmd = CTRL_CMD_GETFAMILY,
1331 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1332 .policy = ctrl_policy_family,
1333 .maxattr = ARRAY_SIZE(ctrl_policy_family) - 1,
1334 .doit = ctrl_getfamily,
1335 .dumpit = ctrl_dumpfamily,
1338 .cmd = CTRL_CMD_GETPOLICY,
1339 .policy = ctrl_policy_policy,
1340 .maxattr = ARRAY_SIZE(ctrl_policy_policy) - 1,
1341 .start = ctrl_dumppolicy_start,
1342 .dumpit = ctrl_dumppolicy,
1343 .done = ctrl_dumppolicy_done,
1347 static const struct genl_multicast_group genl_ctrl_groups[] = {
1348 { .name = "notify", },
1351 static struct genl_family genl_ctrl __ro_after_init = {
1352 .module = THIS_MODULE,
1353 .ops = genl_ctrl_ops,
1354 .n_ops = ARRAY_SIZE(genl_ctrl_ops),
1355 .mcgrps = genl_ctrl_groups,
1356 .n_mcgrps = ARRAY_SIZE(genl_ctrl_groups),
1357 .id = GENL_ID_CTRL,
1358 .name = "nlctrl",
1359 .version = 0x2,
1360 .netnsok = true,
1363 static int __net_init genl_pernet_init(struct net *net)
1365 struct netlink_kernel_cfg cfg = {
1366 .input = genl_rcv,
1367 .flags = NL_CFG_F_NONROOT_RECV,
1370 /* we'll bump the group number right afterwards */
1371 net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg);
1373 if (!net->genl_sock && net_eq(net, &init_net))
1374 panic("GENL: Cannot initialize generic netlink\n");
1376 if (!net->genl_sock)
1377 return -ENOMEM;
1379 return 0;
1382 static void __net_exit genl_pernet_exit(struct net *net)
1384 netlink_kernel_release(net->genl_sock);
1385 net->genl_sock = NULL;
1388 static struct pernet_operations genl_pernet_ops = {
1389 .init = genl_pernet_init,
1390 .exit = genl_pernet_exit,
1393 static int __init genl_init(void)
1395 int err;
1397 err = genl_register_family(&genl_ctrl);
1398 if (err < 0)
1399 goto problem;
1401 err = register_pernet_subsys(&genl_pernet_ops);
1402 if (err)
1403 goto problem;
1405 return 0;
1407 problem:
1408 panic("GENL: Cannot register controller: %d\n", err);
1411 core_initcall(genl_init);
1413 static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
1414 gfp_t flags)
1416 struct sk_buff *tmp;
1417 struct net *net, *prev = NULL;
1418 bool delivered = false;
1419 int err;
1421 for_each_net_rcu(net) {
1422 if (prev) {
1423 tmp = skb_clone(skb, flags);
1424 if (!tmp) {
1425 err = -ENOMEM;
1426 goto error;
1428 err = nlmsg_multicast(prev->genl_sock, tmp,
1429 portid, group, flags);
1430 if (!err)
1431 delivered = true;
1432 else if (err != -ESRCH)
1433 goto error;
1436 prev = net;
1439 err = nlmsg_multicast(prev->genl_sock, skb, portid, group, flags);
1440 if (!err)
1441 delivered = true;
1442 else if (err != -ESRCH)
1443 return err;
1444 return delivered ? 0 : -ESRCH;
1445 error:
1446 kfree_skb(skb);
1447 return err;
1450 int genlmsg_multicast_allns(const struct genl_family *family,
1451 struct sk_buff *skb, u32 portid,
1452 unsigned int group, gfp_t flags)
1454 if (WARN_ON_ONCE(group >= family->n_mcgrps))
1455 return -EINVAL;
1456 group = family->mcgrp_offset + group;
1457 return genlmsg_mcast(skb, portid, group, flags);
1459 EXPORT_SYMBOL(genlmsg_multicast_allns);
1461 void genl_notify(const struct genl_family *family, struct sk_buff *skb,
1462 struct genl_info *info, u32 group, gfp_t flags)
1464 struct net *net = genl_info_net(info);
1465 struct sock *sk = net->genl_sock;
1466 int report = 0;
1468 if (info->nlhdr)
1469 report = nlmsg_report(info->nlhdr);
1471 if (WARN_ON_ONCE(group >= family->n_mcgrps))
1472 return;
1473 group = family->mcgrp_offset + group;
1474 nlmsg_notify(sk, skb, info->snd_portid, group, report, flags);
1476 EXPORT_SYMBOL(genl_notify);