2 * NETLINK Generic Netlink Family
4 * Authors: Jamal Hadi Salim
5 * Thomas Graf <tgraf@suug.ch>
6 * Johannes Berg <johannes@sipsolutions.net>
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>
20 #include <net/genetlink.h>
22 static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */
26 mutex_lock(&genl_mutex);
28 EXPORT_SYMBOL(genl_lock);
30 void genl_unlock(void)
32 mutex_unlock(&genl_mutex);
34 EXPORT_SYMBOL(genl_unlock);
36 #define GENL_FAM_TAB_SIZE 16
37 #define GENL_FAM_TAB_MASK (GENL_FAM_TAB_SIZE - 1)
39 static struct list_head family_ht[GENL_FAM_TAB_SIZE];
41 * Bitmap of multicast groups that are currently in use.
43 * To avoid an allocation at boot of just one unsigned long,
44 * declare it global instead.
45 * Bit 0 is marked as already used since group 0 is invalid.
47 static unsigned long mc_group_start = 0x1;
48 static unsigned long *mc_groups = &mc_group_start;
49 static unsigned long mc_groups_longs = 1;
51 static int genl_ctrl_event(int event, void *data);
53 static inline unsigned int genl_family_hash(unsigned int id)
55 return id & GENL_FAM_TAB_MASK;
58 static inline struct list_head *genl_family_chain(unsigned int id)
60 return &family_ht[genl_family_hash(id)];
63 static struct genl_family *genl_family_find_byid(unsigned int id)
65 struct genl_family *f;
67 list_for_each_entry(f, genl_family_chain(id), family_list)
74 static struct genl_family *genl_family_find_byname(char *name)
76 struct genl_family *f;
79 for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
80 list_for_each_entry(f, genl_family_chain(i), family_list)
81 if (strcmp(f->name, name) == 0)
87 static struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family)
91 list_for_each_entry(ops, &family->ops_list, ops_list)
98 /* Of course we are going to have problems once we hit
99 * 2^16 alive types, but that can only happen by year 2K
101 static inline u16 genl_generate_id(void)
103 static u16 id_gen_idx = GENL_MIN_ID;
106 for (i = 0; i <= GENL_MAX_ID - GENL_MIN_ID; i++) {
107 if (!genl_family_find_byid(id_gen_idx))
109 if (++id_gen_idx > GENL_MAX_ID)
110 id_gen_idx = GENL_MIN_ID;
116 static struct genl_multicast_group notify_grp;
119 * genl_register_mc_group - register a multicast group
121 * Registers the specified multicast group and notifies userspace
122 * about the new group.
124 * Returns 0 on success or a negative error code.
126 * @family: The generic netlink family the group shall be registered for.
127 * @grp: The group to register, must have a name.
129 int genl_register_mc_group(struct genl_family *family,
130 struct genl_multicast_group *grp)
133 unsigned long *new_groups;
136 BUG_ON(grp->name[0] == '\0');
140 /* special-case our own group */
141 if (grp == ¬ify_grp)
144 id = find_first_zero_bit(mc_groups,
145 mc_groups_longs * BITS_PER_LONG);
148 if (id >= mc_groups_longs * BITS_PER_LONG) {
149 size_t nlen = (mc_groups_longs + 1) * sizeof(unsigned long);
151 if (mc_groups == &mc_group_start) {
152 new_groups = kzalloc(nlen, GFP_KERNEL);
157 mc_groups = new_groups;
158 *mc_groups = mc_group_start;
160 new_groups = krealloc(mc_groups, nlen, GFP_KERNEL);
165 mc_groups = new_groups;
166 mc_groups[mc_groups_longs] = 0;
171 if (family->netnsok) {
174 netlink_table_grab();
176 for_each_net_rcu(net) {
177 err = __netlink_change_ngroups(net->genl_sock,
178 mc_groups_longs * BITS_PER_LONG);
181 * No need to roll back, can only fail if
182 * memory allocation fails and then the
183 * number of _possible_ groups has been
184 * increased on some sockets which is ok.
187 netlink_table_ungrab();
192 netlink_table_ungrab();
194 err = netlink_change_ngroups(init_net.genl_sock,
195 mc_groups_longs * BITS_PER_LONG);
201 set_bit(id, mc_groups);
202 list_add_tail(&grp->list, &family->mcast_groups);
203 grp->family = family;
205 genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, grp);
210 EXPORT_SYMBOL(genl_register_mc_group);
212 static void __genl_unregister_mc_group(struct genl_family *family,
213 struct genl_multicast_group *grp)
216 BUG_ON(grp->family != family);
218 netlink_table_grab();
220 for_each_net_rcu(net)
221 __netlink_clear_multicast_users(net->genl_sock, grp->id);
223 netlink_table_ungrab();
225 clear_bit(grp->id, mc_groups);
226 list_del(&grp->list);
227 genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, grp);
233 * genl_unregister_mc_group - unregister a multicast group
235 * Unregisters the specified multicast group and notifies userspace
236 * about it. All current listeners on the group are removed.
238 * Note: It is not necessary to unregister all multicast groups before
239 * unregistering the family, unregistering the family will cause
240 * all assigned multicast groups to be unregistered automatically.
242 * @family: Generic netlink family the group belongs to.
243 * @grp: The group to unregister, must have been registered successfully
246 void genl_unregister_mc_group(struct genl_family *family,
247 struct genl_multicast_group *grp)
250 __genl_unregister_mc_group(family, grp);
253 EXPORT_SYMBOL(genl_unregister_mc_group);
255 static void genl_unregister_mc_groups(struct genl_family *family)
257 struct genl_multicast_group *grp, *tmp;
259 list_for_each_entry_safe(grp, tmp, &family->mcast_groups, list)
260 __genl_unregister_mc_group(family, grp);
264 * genl_register_ops - register generic netlink operations
265 * @family: generic netlink family
266 * @ops: operations to be registered
268 * Registers the specified operations and assigns them to the specified
269 * family. Either a doit or dumpit callback must be specified or the
270 * operation will fail. Only one operation structure per command
271 * identifier may be registered.
273 * See include/net/genetlink.h for more documenation on the operations
276 * Returns 0 on success or a negative error code.
278 int genl_register_ops(struct genl_family *family, struct genl_ops *ops)
282 if (ops->dumpit == NULL && ops->doit == NULL)
285 if (genl_get_cmd(ops->cmd, family)) {
291 ops->flags |= GENL_CMD_CAP_DUMP;
293 ops->flags |= GENL_CMD_CAP_DO;
295 ops->flags |= GENL_CMD_CAP_HASPOL;
298 list_add_tail(&ops->ops_list, &family->ops_list);
301 genl_ctrl_event(CTRL_CMD_NEWOPS, ops);
308 * genl_unregister_ops - unregister generic netlink operations
309 * @family: generic netlink family
310 * @ops: operations to be unregistered
312 * Unregisters the specified operations and unassigns them from the
313 * specified family. The operation blocks until the current message
314 * processing has finished and doesn't start again until the
315 * unregister process has finished.
317 * Note: It is not necessary to unregister all operations before
318 * unregistering the family, unregistering the family will cause
319 * all assigned operations to be unregistered automatically.
321 * Returns 0 on success or a negative error code.
323 int genl_unregister_ops(struct genl_family *family, struct genl_ops *ops)
328 list_for_each_entry(rc, &family->ops_list, ops_list) {
330 list_del(&ops->ops_list);
332 genl_ctrl_event(CTRL_CMD_DELOPS, ops);
342 * genl_register_family - register a generic netlink family
343 * @family: generic netlink family
345 * Registers the specified family after validating it first. Only one
346 * family may be registered with the same family name or identifier.
347 * The family id may equal GENL_ID_GENERATE causing an unique id to
348 * be automatically generated and assigned.
350 * Return 0 on success or a negative error code.
352 int genl_register_family(struct genl_family *family)
356 if (family->id && family->id < GENL_MIN_ID)
359 if (family->id > GENL_MAX_ID)
362 INIT_LIST_HEAD(&family->ops_list);
363 INIT_LIST_HEAD(&family->mcast_groups);
367 if (genl_family_find_byname(family->name)) {
372 if (family->id == GENL_ID_GENERATE) {
373 u16 newid = genl_generate_id();
381 } else if (genl_family_find_byid(family->id)) {
386 if (family->maxattr) {
387 family->attrbuf = kmalloc((family->maxattr+1) *
388 sizeof(struct nlattr *), GFP_KERNEL);
389 if (family->attrbuf == NULL) {
394 family->attrbuf = NULL;
396 list_add_tail(&family->family_list, genl_family_chain(family->id));
399 genl_ctrl_event(CTRL_CMD_NEWFAMILY, family);
410 * genl_register_family_with_ops - register a generic netlink family
411 * @family: generic netlink family
412 * @ops: operations to be registered
413 * @n_ops: number of elements to register
415 * Registers the specified family and operations from the specified table.
416 * Only one family may be registered with the same family name or identifier.
418 * The family id may equal GENL_ID_GENERATE causing an unique id to
419 * be automatically generated and assigned.
421 * Either a doit or dumpit callback must be specified for every registered
422 * operation or the function will fail. Only one operation structure per
423 * command identifier may be registered.
425 * See include/net/genetlink.h for more documenation on the operations
428 * This is equivalent to calling genl_register_family() followed by
429 * genl_register_ops() for every operation entry in the table taking
430 * care to unregister the family on error path.
432 * Return 0 on success or a negative error code.
434 int genl_register_family_with_ops(struct genl_family *family,
435 struct genl_ops *ops, size_t n_ops)
439 err = genl_register_family(family);
443 for (i = 0; i < n_ops; ++i, ++ops) {
444 err = genl_register_ops(family, ops);
450 genl_unregister_family(family);
453 EXPORT_SYMBOL(genl_register_family_with_ops);
456 * genl_unregister_family - unregister generic netlink family
457 * @family: generic netlink family
459 * Unregisters the specified family.
461 * Returns 0 on success or a negative error code.
463 int genl_unregister_family(struct genl_family *family)
465 struct genl_family *rc;
469 genl_unregister_mc_groups(family);
471 list_for_each_entry(rc, genl_family_chain(family->id), family_list) {
472 if (family->id != rc->id || strcmp(rc->name, family->name))
475 list_del(&rc->family_list);
476 INIT_LIST_HEAD(&family->ops_list);
479 kfree(family->attrbuf);
480 genl_ctrl_event(CTRL_CMD_DELFAMILY, family);
489 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
491 struct genl_ops *ops;
492 struct genl_family *family;
493 struct net *net = sock_net(skb->sk);
494 struct genl_info info;
495 struct genlmsghdr *hdr = nlmsg_data(nlh);
498 family = genl_family_find_byid(nlh->nlmsg_type);
502 /* this family doesn't exist in this netns */
503 if (!family->netnsok && !net_eq(net, &init_net))
506 hdrlen = GENL_HDRLEN + family->hdrsize;
507 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
510 ops = genl_get_cmd(hdr->cmd, family);
514 if ((ops->flags & GENL_ADMIN_PERM) &&
515 security_netlink_recv(skb, CAP_NET_ADMIN))
518 if (nlh->nlmsg_flags & NLM_F_DUMP) {
519 if (ops->dumpit == NULL)
523 err = netlink_dump_start(net->genl_sock, skb, nlh,
524 ops->dumpit, ops->done);
529 if (ops->doit == NULL)
532 if (family->attrbuf) {
533 err = nlmsg_parse(nlh, hdrlen, family->attrbuf, family->maxattr,
539 info.snd_seq = nlh->nlmsg_seq;
540 info.snd_pid = NETLINK_CB(skb).pid;
542 info.genlhdr = nlmsg_data(nlh);
543 info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
544 info.attrs = family->attrbuf;
545 genl_info_net_set(&info, net);
547 return ops->doit(skb, &info);
550 static void genl_rcv(struct sk_buff *skb)
553 netlink_rcv_skb(skb, &genl_rcv_msg);
557 /**************************************************************************
559 **************************************************************************/
561 static struct genl_family genl_ctrl = {
565 .maxattr = CTRL_ATTR_MAX,
569 static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
570 u32 flags, struct sk_buff *skb, u8 cmd)
574 hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
578 NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, family->name);
579 NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, family->id);
580 NLA_PUT_U32(skb, CTRL_ATTR_VERSION, family->version);
581 NLA_PUT_U32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize);
582 NLA_PUT_U32(skb, CTRL_ATTR_MAXATTR, family->maxattr);
584 if (!list_empty(&family->ops_list)) {
585 struct nlattr *nla_ops;
586 struct genl_ops *ops;
589 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
591 goto nla_put_failure;
593 list_for_each_entry(ops, &family->ops_list, ops_list) {
596 nest = nla_nest_start(skb, idx++);
598 goto nla_put_failure;
600 NLA_PUT_U32(skb, CTRL_ATTR_OP_ID, ops->cmd);
601 NLA_PUT_U32(skb, CTRL_ATTR_OP_FLAGS, ops->flags);
603 nla_nest_end(skb, nest);
606 nla_nest_end(skb, nla_ops);
609 if (!list_empty(&family->mcast_groups)) {
610 struct genl_multicast_group *grp;
611 struct nlattr *nla_grps;
614 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
615 if (nla_grps == NULL)
616 goto nla_put_failure;
618 list_for_each_entry(grp, &family->mcast_groups, list) {
621 nest = nla_nest_start(skb, idx++);
623 goto nla_put_failure;
625 NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
626 NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
629 nla_nest_end(skb, nest);
631 nla_nest_end(skb, nla_grps);
634 return genlmsg_end(skb, hdr);
637 genlmsg_cancel(skb, hdr);
641 static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 pid,
642 u32 seq, u32 flags, struct sk_buff *skb,
646 struct nlattr *nla_grps;
649 hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
653 NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, grp->family->name);
654 NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, grp->family->id);
656 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
657 if (nla_grps == NULL)
658 goto nla_put_failure;
660 nest = nla_nest_start(skb, 1);
662 goto nla_put_failure;
664 NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
665 NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
668 nla_nest_end(skb, nest);
669 nla_nest_end(skb, nla_grps);
671 return genlmsg_end(skb, hdr);
674 genlmsg_cancel(skb, hdr);
678 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
682 struct genl_family *rt;
683 struct net *net = sock_net(skb->sk);
684 int chains_to_skip = cb->args[0];
685 int fams_to_skip = cb->args[1];
687 for (i = chains_to_skip; i < GENL_FAM_TAB_SIZE; i++) {
689 list_for_each_entry(rt, genl_family_chain(i), family_list) {
690 if (!rt->netnsok && !net_eq(net, &init_net))
692 if (++n < fams_to_skip)
694 if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).pid,
695 cb->nlh->nlmsg_seq, NLM_F_MULTI,
696 skb, CTRL_CMD_NEWFAMILY) < 0)
710 static struct sk_buff *ctrl_build_family_msg(struct genl_family *family,
711 u32 pid, int seq, u8 cmd)
716 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
718 return ERR_PTR(-ENOBUFS);
720 err = ctrl_fill_info(family, pid, seq, 0, skb, cmd);
729 static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_multicast_group *grp,
730 u32 pid, int seq, u8 cmd)
735 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
737 return ERR_PTR(-ENOBUFS);
739 err = ctrl_fill_mcgrp_info(grp, pid, seq, 0, skb, cmd);
748 static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
749 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 },
750 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
751 .len = GENL_NAMSIZ - 1 },
754 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
757 struct genl_family *res = NULL;
760 if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
761 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
762 res = genl_family_find_byid(id);
766 if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
769 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
770 res = genl_family_find_byname(name);
777 if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) {
778 /* family doesn't exist here */
782 msg = ctrl_build_family_msg(res, info->snd_pid, info->snd_seq,
787 return genlmsg_reply(msg, info);
790 static int genl_ctrl_event(int event, void *data)
793 struct genl_family *family;
794 struct genl_multicast_group *grp;
796 /* genl is still initialising */
797 if (!init_net.genl_sock)
801 case CTRL_CMD_NEWFAMILY:
802 case CTRL_CMD_DELFAMILY:
804 msg = ctrl_build_family_msg(family, 0, 0, event);
806 case CTRL_CMD_NEWMCAST_GRP:
807 case CTRL_CMD_DELMCAST_GRP:
809 family = grp->family;
810 msg = ctrl_build_mcgrp_msg(data, 0, 0, event);
819 if (!family->netnsok) {
820 genlmsg_multicast_netns(&init_net, msg, 0,
821 GENL_ID_CTRL, GFP_KERNEL);
824 genlmsg_multicast_allns(msg, 0, GENL_ID_CTRL, GFP_ATOMIC);
831 static struct genl_ops genl_ctrl_ops = {
832 .cmd = CTRL_CMD_GETFAMILY,
833 .doit = ctrl_getfamily,
834 .dumpit = ctrl_dumpfamily,
835 .policy = ctrl_policy,
838 static struct genl_multicast_group notify_grp = {
842 static int __net_init genl_pernet_init(struct net *net)
844 /* we'll bump the group number right afterwards */
845 net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, 0,
846 genl_rcv, &genl_mutex,
849 if (!net->genl_sock && net_eq(net, &init_net))
850 panic("GENL: Cannot initialize generic netlink\n");
858 static void __net_exit genl_pernet_exit(struct net *net)
860 netlink_kernel_release(net->genl_sock);
861 net->genl_sock = NULL;
864 static struct pernet_operations genl_pernet_ops = {
865 .init = genl_pernet_init,
866 .exit = genl_pernet_exit,
869 static int __init genl_init(void)
873 for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
874 INIT_LIST_HEAD(&family_ht[i]);
876 err = genl_register_family(&genl_ctrl);
880 err = genl_register_ops(&genl_ctrl, &genl_ctrl_ops);
884 netlink_set_nonroot(NETLINK_GENERIC, NL_NONROOT_RECV);
886 err = register_pernet_subsys(&genl_pernet_ops);
890 err = genl_register_mc_group(&genl_ctrl, ¬ify_grp);
897 panic("GENL: Cannot register controller: %d\n", err);
900 subsys_initcall(genl_init);
902 EXPORT_SYMBOL(genl_register_ops);
903 EXPORT_SYMBOL(genl_unregister_ops);
904 EXPORT_SYMBOL(genl_register_family);
905 EXPORT_SYMBOL(genl_unregister_family);
907 static int genlmsg_mcast(struct sk_buff *skb, u32 pid, unsigned long group,
911 struct net *net, *prev = NULL;
914 for_each_net_rcu(net) {
916 tmp = skb_clone(skb, flags);
921 err = nlmsg_multicast(prev->genl_sock, tmp,
930 return nlmsg_multicast(prev->genl_sock, skb, pid, group, flags);
936 int genlmsg_multicast_allns(struct sk_buff *skb, u32 pid, unsigned int group,
939 return genlmsg_mcast(skb, pid, group, flags);
941 EXPORT_SYMBOL(genlmsg_multicast_allns);