1 // SPDX-License-Identifier: GPL-2.0
3 * NETLINK Generic Netlink Family
5 * Authors: Jamal Hadi Salim
6 * Thomas Graf <tgraf@suug.ch>
7 * Johannes Berg <johannes@sipsolutions.net>
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>
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);
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);
44 bool lockdep_genl_is_held(void)
46 return lockdep_is_held(&genl_mutex);
48 EXPORT_SYMBOL(lockdep_genl_is_held);
51 static void genl_lock_all(void)
57 static void genl_unlock_all(void)
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) |
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,
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;
103 idr_for_each_entry(&genl_fam_idr, family, id)
104 if (strcmp(family->name, name) == 0)
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];
121 op->maxattr = family->maxattr;
123 op->policy = family->policy;
126 static int genl_get_cmd_full(u32 cmd, const struct genl_family *family,
131 for (i = 0; i < family->n_ops; i++)
132 if (family->ops[i].cmd == cmd) {
133 genl_op_from_full(family, i, op);
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,
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);
169 static int genl_get_cmd(u32 cmd, const struct genl_family *family,
172 if (!genl_get_cmd_full(cmd, family, op))
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,
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);
189 static int genl_allocate_reserve_groups(int n_groups, int *first_id)
191 unsigned long *new_groups;
199 id = find_first_zero_bit(mc_groups,
203 id = find_next_zero_bit(mc_groups,
204 mc_groups_longs * BITS_PER_LONG,
209 i < min_t(int, id + n_groups,
210 mc_groups_longs * BITS_PER_LONG);
212 if (test_bit(i, mc_groups)) {
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);
228 mc_groups = new_groups;
229 *mc_groups = mc_group_start;
231 new_groups = krealloc(mc_groups, nlen,
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;
243 for (i = id; i < id + n_groups; i++)
244 set_bit(i, mc_groups);
249 static struct genl_family genl_ctrl;
251 static int genl_validate_assign_mc_groups(struct genl_family *family)
254 int n_groups = family->n_mcgrps;
256 bool groups_allocated = false;
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'))
266 if (WARN_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL))
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) {
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);
284 groups_allocated = true;
285 err = genl_allocate_reserve_groups(n_groups, &first_id);
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)
296 if (family->netnsok) {
299 netlink_table_grab();
301 for_each_net_rcu(net) {
302 err = __netlink_change_ngroups(net->genl_sock,
303 mc_groups_longs * BITS_PER_LONG);
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.
315 netlink_table_ungrab();
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);
329 static void genl_unregister_mc_groups(const struct genl_family *family)
334 netlink_table_grab();
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);
342 netlink_table_ungrab();
344 for (i = 0; i < family->n_mcgrps; i++) {
345 int grp_id = family->mcgrp_offset + i;
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)
358 if (WARN_ON(family->n_ops && !family->ops) ||
359 WARN_ON(family->n_small_ops && !family->small_ops))
362 for (i = 0; i < genl_get_cmd_cnt(family); i++) {
365 genl_get_cmd_by_index(i, family, &op);
366 if (op.dumpit == NULL && op.doit == NULL)
368 for (j = i + 1; j < genl_get_cmd_cnt(family); j++) {
371 genl_get_cmd_by_index(j, family, &op2);
372 if (op.cmd == op2.cmd)
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
390 * Return 0 on success or a negative error code.
392 int genl_register_family(struct genl_family *family)
395 int start = GENL_START_ALLOC, end = GENL_MAX_ID;
397 err = genl_validate_ops(family);
403 if (genl_family_find_byname(family->name)) {
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) {
431 err = genl_validate_assign_mc_groups(family);
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);
446 idr_remove(&genl_fam_idr, family->id);
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)
465 if (!genl_family_find_byid(family->id)) {
470 genl_unregister_mc_groups(family);
472 idr_remove(&genl_fam_idr, family->id);
475 wait_event(genl_sk_destructing_waitq,
476 atomic_read(&genl_sk_destructing_cnt) == 0);
479 genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 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);
507 hdr = nlmsg_data(nlh);
509 hdr->version = family->version;
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)
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,
532 enum genl_validate_flags no_strict_flag)
534 enum netlink_validation validate = ops->validate & no_strict_flag ?
535 NL_VALIDATE_LIBERAL :
537 struct nlattr **attrbuf;
543 attrbuf = kmalloc_array(ops->maxattr + 1,
544 sizeof(struct nlattr *), GFP_KERNEL);
546 return ERR_PTR(-ENOMEM);
548 err = __nlmsg_parse(nlh, hdrlen, attrbuf, ops->maxattr, ops->policy,
557 static void genl_family_rcv_msg_attrs_free(struct nlattr **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;
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;
578 if (ops->validate & GENL_DONT_VALIDATE_DUMP)
581 if (ctx->nlh->nlmsg_len < nlmsg_msg_size(ctx->hdrlen))
584 attrs = genl_family_rcv_msg_attrs_parse(ctx->family, ctx->nlh, ctx->extack,
586 GENL_DONT_VALIDATE_DUMP_STRICT);
588 return PTR_ERR(attrs);
591 info = genl_dumpit_info_alloc();
593 genl_family_rcv_msg_attrs_free(attrs);
596 info->family = ctx->family;
602 if (!ctx->family->parallel_ops)
605 if (!ctx->family->parallel_ops)
610 genl_family_rcv_msg_attrs_free(info->attrs);
611 genl_dumpit_info_free(info);
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;
623 rc = ops->dumpit(skb, cb);
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;
639 genl_family_rcv_msg_attrs_free(info->attrs);
640 genl_dumpit_info_free(info);
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;
652 genl_family_rcv_msg_attrs_free(info->attrs);
653 genl_dumpit_info_free(info);
657 static int genl_family_rcv_msg_dumpit(const struct genl_family *family,
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;
676 if (!family->parallel_ops) {
677 struct netlink_dump_control c = {
678 .module = family->module,
681 .dump = genl_lock_dumpit,
682 .done = genl_lock_done,
686 err = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
689 struct netlink_dump_control c = {
690 .module = family->module,
694 .done = genl_parallel_done,
697 err = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
703 static int genl_family_rcv_msg_doit(const struct genl_family *family,
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;
717 attrbuf = genl_family_rcv_msg_attrs_parse(family, nlh, extack,
719 GENL_DONT_VALIDATE_STRICT);
721 return PTR_ERR(attrbuf);
723 info.snd_seq = nlh->nlmsg_seq;
724 info.snd_portid = NETLINK_CB(skb).portid;
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);
739 err = ops->doit(skb, &info);
741 if (family->post_doit)
742 family->post_doit(ops, skb, &info);
745 genl_family_rcv_msg_attrs_free(attrbuf);
750 static int genl_family_rcv_msg(const struct genl_family *family,
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);
760 /* this family doesn't exist in this netns */
761 if (!family->netnsok && !net_eq(net, &init_net))
764 hdrlen = GENL_HDRLEN + family->hdrsize;
765 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
768 if (genl_get_cmd(hdr->cmd, family, &op))
771 if ((op.flags & GENL_ADMIN_PERM) &&
772 !netlink_capable(skb, CAP_NET_ADMIN))
775 if ((op.flags & GENL_UNS_ADMIN_PERM) &&
776 !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
779 if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP)
780 return genl_family_rcv_msg_dumpit(family, skb, nlh, extack,
783 return genl_family_rcv_msg_doit(family, skb, nlh, extack,
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;
793 family = genl_family_find_byid(nlh->nlmsg_type);
797 if (!family->parallel_ops)
800 err = genl_family_rcv_msg(family, skb, nlh, extack);
802 if (!family->parallel_ops)
808 static void genl_rcv(struct sk_buff *skb)
811 netlink_rcv_skb(skb, &genl_rcv_msg);
815 /**************************************************************************
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)
826 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
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;
841 nla_ops = nla_nest_start_noflag(skb, CTRL_ATTR_OPS);
843 goto nla_put_failure;
845 for (i = 0; i < genl_get_cmd_cnt(family); i++) {
850 genl_get_cmd_by_index(i, family, &op);
853 op_flags |= GENL_CMD_CAP_DUMP;
855 op_flags |= GENL_CMD_CAP_DO;
857 op_flags |= GENL_CMD_CAP_HASPOL;
859 nest = nla_nest_start_noflag(skb, i + 1);
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;
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++) {
883 const struct genl_multicast_group *grp;
885 grp = &family->mcgrps[i];
887 nest = nla_nest_start_noflag(skb, i + 1);
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,
895 goto nla_put_failure;
897 nla_nest_end(skb, nest);
899 nla_nest_end(skb, nla_grps);
902 genlmsg_end(skb, hdr);
906 genlmsg_cancel(skb, hdr);
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)
916 struct nlattr *nla_grps;
919 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
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);
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,
938 goto nla_put_failure;
940 nla_nest_end(skb, nest);
941 nla_nest_end(skb, nla_grps);
943 genlmsg_end(skb, hdr);
947 genlmsg_cancel(skb, hdr);
951 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
954 struct genl_family *rt;
955 struct net *net = sock_net(skb->sk);
956 int fams_to_skip = cb->args[0];
959 idr_for_each_entry(&genl_fam_idr, rt, id) {
960 if (!rt->netnsok && !net_eq(net, &init_net))
963 if (n++ < fams_to_skip)
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) {
978 static struct sk_buff *ctrl_build_family_msg(const struct genl_family *family,
979 u32 portid, int seq, u8 cmd)
984 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
986 return ERR_PTR(-ENOBUFS);
988 err = ctrl_fill_info(family, portid, seq, 0, skb, cmd);
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;
1005 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1007 return ERR_PTR(-ENOBUFS);
1009 err = ctrl_fill_mcgrp_info(family, grp, grp_id, portid,
1013 return ERR_PTR(err);
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;
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);
1037 if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
1040 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
1041 res = genl_family_find_byname(name);
1042 #ifdef CONFIG_MODULES
1046 request_module("net-pf-%d-proto-%d-family-%s",
1047 PF_NETLINK, NETLINK_GENERIC, name);
1048 down_read(&cb_lock);
1050 res = genl_family_find_byname(name);
1059 if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) {
1060 /* family doesn't exist here */
1064 msg = ctrl_build_family_msg(res, info->snd_portid, info->snd_seq,
1065 CTRL_CMD_NEWFAMILY);
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,
1076 struct sk_buff *msg;
1078 /* genl is still initialising */
1079 if (!init_net.genl_sock)
1083 case CTRL_CMD_NEWFAMILY:
1084 case CTRL_CMD_DELFAMILY:
1086 msg = ctrl_build_family_msg(family, 0, 0, event);
1088 case CTRL_CMD_NEWMCAST_GRP:
1089 case CTRL_CMD_DELMCAST_GRP:
1091 msg = ctrl_build_mcgrp_msg(family, grp, grp_id, 0, 0, event);
1098 return PTR_ERR(msg);
1100 if (!family->netnsok) {
1101 genlmsg_multicast_netns(&genl_ctrl, &init_net, msg, 0,
1105 genlmsg_multicast_allns(&genl_ctrl, msg, 0,
1113 struct ctrl_dump_policy_ctx {
1114 struct netlink_policy_dump_state *state;
1115 const struct genl_family *rt;
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;
1139 BUILD_BUG_ON(sizeof(*ctx) > sizeof(cb->ctx));
1141 if (!tb[CTRL_ATTR_FAMILY_ID] && !tb[CTRL_ATTR_FAMILY_NAME])
1144 if (tb[CTRL_ATTR_FAMILY_ID]) {
1145 ctx->fam_id = nla_get_u16(tb[CTRL_ATTR_FAMILY_ID]);
1147 rt = genl_family_find_byname(
1148 nla_data(tb[CTRL_ATTR_FAMILY_NAME]));
1151 ctx->fam_id = rt->id;
1154 rt = genl_family_find_byid(ctx->fam_id);
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);
1166 NL_SET_BAD_ATTR(cb->extack, tb[CTRL_ATTR_OP]);
1173 return netlink_policy_dump_add_policy(&ctx->state, op.policy,
1177 for (i = 0; i < genl_get_cmd_cnt(rt); i++) {
1178 genl_get_cmd_by_index(i, rt, &op);
1181 err = netlink_policy_dump_add_policy(&ctx->state,
1185 goto err_free_state;
1194 netlink_policy_dump_free(ctx->state);
1198 static void *ctrl_dumppolicy_prep(struct sk_buff *skb,
1199 struct netlink_callback *cb)
1201 struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
1204 hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid,
1205 cb->nlh->nlmsg_seq, &genl_ctrl,
1206 NLM_F_MULTI, CTRL_CMD_GETPOLICY);
1210 if (nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, ctx->fam_id))
1216 static int ctrl_dumppolicy_put_op(struct sk_buff *skb,
1217 struct netlink_callback *cb,
1218 struct genl_ops *op)
1220 struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
1221 struct nlattr *nest_pol, *nest_op;
1225 /* skip if we have nothing to show */
1229 (!op->dumpit || op->validate & GENL_DONT_VALIDATE_DUMP))
1232 hdr = ctrl_dumppolicy_prep(skb, cb);
1236 nest_pol = nla_nest_start(skb, CTRL_ATTR_OP_POLICY);
1240 nest_op = nla_nest_start(skb, op->cmd);
1244 /* for now both do/dump are always the same */
1245 idx = netlink_policy_dump_get_policy_idx(ctx->state,
1249 if (op->doit && nla_put_u32(skb, CTRL_ATTR_POLICY_DO, idx))
1252 if (op->dumpit && !(op->validate & GENL_DONT_VALIDATE_DUMP) &&
1253 nla_put_u32(skb, CTRL_ATTR_POLICY_DUMP, idx))
1256 nla_nest_end(skb, nest_op);
1257 nla_nest_end(skb, nest_pol);
1258 genlmsg_end(skb, hdr);
1262 genlmsg_cancel(skb, hdr);
1266 static int ctrl_dumppolicy(struct sk_buff *skb, struct netlink_callback *cb)
1268 struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
1271 if (!ctx->policies) {
1272 while (ctx->opidx < genl_get_cmd_cnt(ctx->rt)) {
1275 if (ctx->single_op) {
1278 err = genl_get_cmd(ctx->op, ctx->rt, &op);
1282 /* break out of the loop after this one */
1283 ctx->opidx = genl_get_cmd_cnt(ctx->rt);
1285 genl_get_cmd_by_index(ctx->opidx, ctx->rt, &op);
1288 if (ctrl_dumppolicy_put_op(skb, cb, &op))
1294 /* completed with the per-op policy index list */
1295 ctx->policies = true;
1298 while (netlink_policy_dump_loop(ctx->state)) {
1299 struct nlattr *nest;
1301 hdr = ctrl_dumppolicy_prep(skb, cb);
1303 goto nla_put_failure;
1305 nest = nla_nest_start(skb, CTRL_ATTR_POLICY);
1307 goto nla_put_failure;
1309 if (netlink_policy_dump_write(skb, ctx->state))
1310 goto nla_put_failure;
1312 nla_nest_end(skb, nest);
1314 genlmsg_end(skb, hdr);
1320 genlmsg_cancel(skb, hdr);
1324 static int ctrl_dumppolicy_done(struct netlink_callback *cb)
1326 struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
1328 netlink_policy_dump_free(ctx->state);
1332 static const struct genl_ops genl_ctrl_ops[] = {
1334 .cmd = CTRL_CMD_GETFAMILY,
1335 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1336 .policy = ctrl_policy_family,
1337 .maxattr = ARRAY_SIZE(ctrl_policy_family) - 1,
1338 .doit = ctrl_getfamily,
1339 .dumpit = ctrl_dumpfamily,
1342 .cmd = CTRL_CMD_GETPOLICY,
1343 .policy = ctrl_policy_policy,
1344 .maxattr = ARRAY_SIZE(ctrl_policy_policy) - 1,
1345 .start = ctrl_dumppolicy_start,
1346 .dumpit = ctrl_dumppolicy,
1347 .done = ctrl_dumppolicy_done,
1351 static const struct genl_multicast_group genl_ctrl_groups[] = {
1352 { .name = "notify", },
1355 static struct genl_family genl_ctrl __ro_after_init = {
1356 .module = THIS_MODULE,
1357 .ops = genl_ctrl_ops,
1358 .n_ops = ARRAY_SIZE(genl_ctrl_ops),
1359 .mcgrps = genl_ctrl_groups,
1360 .n_mcgrps = ARRAY_SIZE(genl_ctrl_groups),
1367 static int genl_bind(struct net *net, int group)
1369 const struct genl_family *family;
1375 idr_for_each_entry(&genl_fam_idr, family, id) {
1376 const struct genl_multicast_group *grp;
1379 if (family->n_mcgrps == 0)
1382 i = group - family->mcgrp_offset;
1383 if (i < 0 || i >= family->n_mcgrps)
1386 grp = &family->mcgrps[i];
1387 if ((grp->flags & GENL_UNS_ADMIN_PERM) &&
1388 !ns_capable(net->user_ns, CAP_NET_ADMIN))
1390 if (grp->cap_sys_admin &&
1391 !ns_capable(net->user_ns, CAP_SYS_ADMIN))
1401 static int __net_init genl_pernet_init(struct net *net)
1403 struct netlink_kernel_cfg cfg = {
1405 .flags = NL_CFG_F_NONROOT_RECV,
1409 /* we'll bump the group number right afterwards */
1410 net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg);
1412 if (!net->genl_sock && net_eq(net, &init_net))
1413 panic("GENL: Cannot initialize generic netlink\n");
1415 if (!net->genl_sock)
1421 static void __net_exit genl_pernet_exit(struct net *net)
1423 netlink_kernel_release(net->genl_sock);
1424 net->genl_sock = NULL;
1427 static struct pernet_operations genl_pernet_ops = {
1428 .init = genl_pernet_init,
1429 .exit = genl_pernet_exit,
1432 static int __init genl_init(void)
1436 err = genl_register_family(&genl_ctrl);
1440 err = register_pernet_subsys(&genl_pernet_ops);
1447 panic("GENL: Cannot register controller: %d\n", err);
1450 core_initcall(genl_init);
1452 static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
1455 struct sk_buff *tmp;
1456 struct net *net, *prev = NULL;
1457 bool delivered = false;
1460 for_each_net_rcu(net) {
1462 tmp = skb_clone(skb, flags);
1467 err = nlmsg_multicast(prev->genl_sock, tmp,
1468 portid, group, flags);
1471 else if (err != -ESRCH)
1478 err = nlmsg_multicast(prev->genl_sock, skb, portid, group, flags);
1481 else if (err != -ESRCH)
1483 return delivered ? 0 : -ESRCH;
1489 int genlmsg_multicast_allns(const struct genl_family *family,
1490 struct sk_buff *skb, u32 portid,
1491 unsigned int group, gfp_t flags)
1493 if (WARN_ON_ONCE(group >= family->n_mcgrps))
1495 group = family->mcgrp_offset + group;
1496 return genlmsg_mcast(skb, portid, group, flags);
1498 EXPORT_SYMBOL(genlmsg_multicast_allns);
1500 void genl_notify(const struct genl_family *family, struct sk_buff *skb,
1501 struct genl_info *info, u32 group, gfp_t flags)
1503 struct net *net = genl_info_net(info);
1504 struct sock *sk = net->genl_sock;
1508 report = nlmsg_report(info->nlhdr);
1510 if (WARN_ON_ONCE(group >= family->n_mcgrps))
1512 group = family->mcgrp_offset + group;
1513 nlmsg_notify(sk, skb, info->snd_portid, group, report, flags);
1515 EXPORT_SYMBOL(genl_notify);