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/errno.h>
12 #include <linux/types.h>
13 #include <linux/socket.h>
14 #include <linux/string.h>
15 #include <linux/skbuff.h>
16 #include <linux/mutex.h>
17 #include <linux/bitmap.h>
19 #include <net/genetlink.h>
21 struct sock *genl_sock = NULL;
23 static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */
25 static inline void genl_lock(void)
27 mutex_lock(&genl_mutex);
30 static inline void genl_unlock(void)
32 mutex_unlock(&genl_mutex);
35 #define GENL_FAM_TAB_SIZE 16
36 #define GENL_FAM_TAB_MASK (GENL_FAM_TAB_SIZE - 1)
38 static struct list_head family_ht[GENL_FAM_TAB_SIZE];
40 * Bitmap of multicast groups that are currently in use.
42 * To avoid an allocation at boot of just one unsigned long,
43 * declare it global instead.
44 * Bit 0 is marked as already used since group 0 is invalid.
46 static unsigned long mc_group_start = 0x1;
47 static unsigned long *mc_groups = &mc_group_start;
48 static unsigned long mc_groups_longs = 1;
50 static int genl_ctrl_event(int event, void *data);
52 static inline unsigned int genl_family_hash(unsigned int id)
54 return id & GENL_FAM_TAB_MASK;
57 static inline struct list_head *genl_family_chain(unsigned int id)
59 return &family_ht[genl_family_hash(id)];
62 static struct genl_family *genl_family_find_byid(unsigned int id)
64 struct genl_family *f;
66 list_for_each_entry(f, genl_family_chain(id), family_list)
73 static struct genl_family *genl_family_find_byname(char *name)
75 struct genl_family *f;
78 for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
79 list_for_each_entry(f, genl_family_chain(i), family_list)
80 if (strcmp(f->name, name) == 0)
86 static struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family)
90 list_for_each_entry(ops, &family->ops_list, ops_list)
97 /* Of course we are going to have problems once we hit
98 * 2^16 alive types, but that can only happen by year 2K
100 static inline u16 genl_generate_id(void)
102 static u16 id_gen_idx;
107 id_gen_idx = GENL_MIN_ID;
109 if (++id_gen_idx > GENL_MAX_ID) {
118 } while (genl_family_find_byid(id_gen_idx));
123 static struct genl_multicast_group notify_grp;
126 * genl_register_mc_group - register a multicast group
128 * Registers the specified multicast group and notifies userspace
129 * about the new group.
131 * Returns 0 on success or a negative error code.
133 * @family: The generic netlink family the group shall be registered for.
134 * @grp: The group to register, must have a name.
136 int genl_register_mc_group(struct genl_family *family,
137 struct genl_multicast_group *grp)
140 unsigned long *new_groups;
143 BUG_ON(grp->name[0] == '\0');
147 /* special-case our own group */
148 if (grp == ¬ify_grp)
151 id = find_first_zero_bit(mc_groups,
152 mc_groups_longs * BITS_PER_LONG);
155 if (id >= mc_groups_longs * BITS_PER_LONG) {
156 size_t nlen = (mc_groups_longs + 1) * sizeof(unsigned long);
158 if (mc_groups == &mc_group_start) {
159 new_groups = kzalloc(nlen, GFP_KERNEL);
164 mc_groups = new_groups;
165 *mc_groups = mc_group_start;
167 new_groups = krealloc(mc_groups, nlen, GFP_KERNEL);
172 mc_groups = new_groups;
173 mc_groups[mc_groups_longs] = 0;
178 err = netlink_change_ngroups(genl_sock,
179 mc_groups_longs * BITS_PER_LONG);
184 set_bit(id, mc_groups);
185 list_add_tail(&grp->list, &family->mcast_groups);
186 grp->family = family;
188 genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, grp);
193 EXPORT_SYMBOL(genl_register_mc_group);
195 static void __genl_unregister_mc_group(struct genl_family *family,
196 struct genl_multicast_group *grp)
198 BUG_ON(grp->family != family);
199 netlink_clear_multicast_users(genl_sock, grp->id);
200 clear_bit(grp->id, mc_groups);
201 list_del(&grp->list);
202 genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, grp);
208 * genl_unregister_mc_group - unregister a multicast group
210 * Unregisters the specified multicast group and notifies userspace
211 * about it. All current listeners on the group are removed.
213 * Note: It is not necessary to unregister all multicast groups before
214 * unregistering the family, unregistering the family will cause
215 * all assigned multicast groups to be unregistered automatically.
217 * @family: Generic netlink family the group belongs to.
218 * @grp: The group to unregister, must have been registered successfully
221 void genl_unregister_mc_group(struct genl_family *family,
222 struct genl_multicast_group *grp)
225 __genl_unregister_mc_group(family, grp);
228 EXPORT_SYMBOL(genl_unregister_mc_group);
230 static void genl_unregister_mc_groups(struct genl_family *family)
232 struct genl_multicast_group *grp, *tmp;
234 list_for_each_entry_safe(grp, tmp, &family->mcast_groups, list)
235 __genl_unregister_mc_group(family, grp);
239 * genl_register_ops - register generic netlink operations
240 * @family: generic netlink family
241 * @ops: operations to be registered
243 * Registers the specified operations and assigns them to the specified
244 * family. Either a doit or dumpit callback must be specified or the
245 * operation will fail. Only one operation structure per command
246 * identifier may be registered.
248 * See include/net/genetlink.h for more documenation on the operations
251 * Returns 0 on success or a negative error code.
253 int genl_register_ops(struct genl_family *family, struct genl_ops *ops)
257 if (ops->dumpit == NULL && ops->doit == NULL)
260 if (genl_get_cmd(ops->cmd, family)) {
266 ops->flags |= GENL_CMD_CAP_DUMP;
268 ops->flags |= GENL_CMD_CAP_DO;
270 ops->flags |= GENL_CMD_CAP_HASPOL;
273 list_add_tail(&ops->ops_list, &family->ops_list);
276 genl_ctrl_event(CTRL_CMD_NEWOPS, ops);
283 * genl_unregister_ops - unregister generic netlink operations
284 * @family: generic netlink family
285 * @ops: operations to be unregistered
287 * Unregisters the specified operations and unassigns them from the
288 * specified family. The operation blocks until the current message
289 * processing has finished and doesn't start again until the
290 * unregister process has finished.
292 * Note: It is not necessary to unregister all operations before
293 * unregistering the family, unregistering the family will cause
294 * all assigned operations to be unregistered automatically.
296 * Returns 0 on success or a negative error code.
298 int genl_unregister_ops(struct genl_family *family, struct genl_ops *ops)
303 list_for_each_entry(rc, &family->ops_list, ops_list) {
305 list_del(&ops->ops_list);
307 genl_ctrl_event(CTRL_CMD_DELOPS, ops);
317 * genl_register_family - register a generic netlink family
318 * @family: generic netlink family
320 * Registers the specified family after validating it first. Only one
321 * family may be registered with the same family name or identifier.
322 * The family id may equal GENL_ID_GENERATE causing an unique id to
323 * be automatically generated and assigned.
325 * Return 0 on success or a negative error code.
327 int genl_register_family(struct genl_family *family)
331 if (family->id && family->id < GENL_MIN_ID)
334 if (family->id > GENL_MAX_ID)
337 INIT_LIST_HEAD(&family->ops_list);
338 INIT_LIST_HEAD(&family->mcast_groups);
342 if (genl_family_find_byname(family->name)) {
347 if (genl_family_find_byid(family->id)) {
352 if (family->id == GENL_ID_GENERATE) {
353 u16 newid = genl_generate_id();
363 if (family->maxattr) {
364 family->attrbuf = kmalloc((family->maxattr+1) *
365 sizeof(struct nlattr *), GFP_KERNEL);
366 if (family->attrbuf == NULL) {
371 family->attrbuf = NULL;
373 list_add_tail(&family->family_list, genl_family_chain(family->id));
376 genl_ctrl_event(CTRL_CMD_NEWFAMILY, family);
387 * genl_register_family_with_ops - register a generic netlink family
388 * @family: generic netlink family
389 * @ops: operations to be registered
390 * @n_ops: number of elements to register
392 * Registers the specified family and operations from the specified table.
393 * Only one family may be registered with the same family name or identifier.
395 * The family id may equal GENL_ID_GENERATE causing an unique id to
396 * be automatically generated and assigned.
398 * Either a doit or dumpit callback must be specified for every registered
399 * operation or the function will fail. Only one operation structure per
400 * command identifier may be registered.
402 * See include/net/genetlink.h for more documenation on the operations
405 * This is equivalent to calling genl_register_family() followed by
406 * genl_register_ops() for every operation entry in the table taking
407 * care to unregister the family on error path.
409 * Return 0 on success or a negative error code.
411 int genl_register_family_with_ops(struct genl_family *family,
412 struct genl_ops *ops, size_t n_ops)
416 err = genl_register_family(family);
420 for (i = 0; i < n_ops; ++i, ++ops) {
421 err = genl_register_ops(family, ops);
427 genl_unregister_family(family);
430 EXPORT_SYMBOL(genl_register_family_with_ops);
433 * genl_unregister_family - unregister generic netlink family
434 * @family: generic netlink family
436 * Unregisters the specified family.
438 * Returns 0 on success or a negative error code.
440 int genl_unregister_family(struct genl_family *family)
442 struct genl_family *rc;
446 genl_unregister_mc_groups(family);
448 list_for_each_entry(rc, genl_family_chain(family->id), family_list) {
449 if (family->id != rc->id || strcmp(rc->name, family->name))
452 list_del(&rc->family_list);
453 INIT_LIST_HEAD(&family->ops_list);
456 kfree(family->attrbuf);
457 genl_ctrl_event(CTRL_CMD_DELFAMILY, family);
466 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
468 struct genl_ops *ops;
469 struct genl_family *family;
470 struct genl_info info;
471 struct genlmsghdr *hdr = nlmsg_data(nlh);
474 family = genl_family_find_byid(nlh->nlmsg_type);
478 hdrlen = GENL_HDRLEN + family->hdrsize;
479 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
482 ops = genl_get_cmd(hdr->cmd, family);
486 if ((ops->flags & GENL_ADMIN_PERM) &&
487 security_netlink_recv(skb, CAP_NET_ADMIN))
490 if (nlh->nlmsg_flags & NLM_F_DUMP) {
491 if (ops->dumpit == NULL)
495 err = netlink_dump_start(genl_sock, skb, nlh,
496 ops->dumpit, ops->done);
501 if (ops->doit == NULL)
504 if (family->attrbuf) {
505 err = nlmsg_parse(nlh, hdrlen, family->attrbuf, family->maxattr,
511 info.snd_seq = nlh->nlmsg_seq;
512 info.snd_pid = NETLINK_CB(skb).pid;
514 info.genlhdr = nlmsg_data(nlh);
515 info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
516 info.attrs = family->attrbuf;
518 return ops->doit(skb, &info);
521 static void genl_rcv(struct sk_buff *skb)
524 netlink_rcv_skb(skb, &genl_rcv_msg);
528 /**************************************************************************
530 **************************************************************************/
532 static struct genl_family genl_ctrl = {
536 .maxattr = CTRL_ATTR_MAX,
539 static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
540 u32 flags, struct sk_buff *skb, u8 cmd)
544 hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
548 NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, family->name);
549 NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, family->id);
550 NLA_PUT_U32(skb, CTRL_ATTR_VERSION, family->version);
551 NLA_PUT_U32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize);
552 NLA_PUT_U32(skb, CTRL_ATTR_MAXATTR, family->maxattr);
554 if (!list_empty(&family->ops_list)) {
555 struct nlattr *nla_ops;
556 struct genl_ops *ops;
559 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
561 goto nla_put_failure;
563 list_for_each_entry(ops, &family->ops_list, ops_list) {
566 nest = nla_nest_start(skb, idx++);
568 goto nla_put_failure;
570 NLA_PUT_U32(skb, CTRL_ATTR_OP_ID, ops->cmd);
571 NLA_PUT_U32(skb, CTRL_ATTR_OP_FLAGS, ops->flags);
573 nla_nest_end(skb, nest);
576 nla_nest_end(skb, nla_ops);
579 if (!list_empty(&family->mcast_groups)) {
580 struct genl_multicast_group *grp;
581 struct nlattr *nla_grps;
584 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
585 if (nla_grps == NULL)
586 goto nla_put_failure;
588 list_for_each_entry(grp, &family->mcast_groups, list) {
591 nest = nla_nest_start(skb, idx++);
593 goto nla_put_failure;
595 NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
596 NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
599 nla_nest_end(skb, nest);
601 nla_nest_end(skb, nla_grps);
604 return genlmsg_end(skb, hdr);
607 genlmsg_cancel(skb, hdr);
611 static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 pid,
612 u32 seq, u32 flags, struct sk_buff *skb,
616 struct nlattr *nla_grps;
619 hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
623 NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, grp->family->name);
624 NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, grp->family->id);
626 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
627 if (nla_grps == NULL)
628 goto nla_put_failure;
630 nest = nla_nest_start(skb, 1);
632 goto nla_put_failure;
634 NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
635 NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
638 nla_nest_end(skb, nest);
639 nla_nest_end(skb, nla_grps);
641 return genlmsg_end(skb, hdr);
644 genlmsg_cancel(skb, hdr);
648 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
652 struct genl_family *rt;
653 int chains_to_skip = cb->args[0];
654 int fams_to_skip = cb->args[1];
656 for (i = 0; i < GENL_FAM_TAB_SIZE; i++) {
657 if (i < chains_to_skip)
660 list_for_each_entry(rt, genl_family_chain(i), family_list) {
661 if (++n < fams_to_skip)
663 if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).pid,
664 cb->nlh->nlmsg_seq, NLM_F_MULTI,
665 skb, CTRL_CMD_NEWFAMILY) < 0)
679 static struct sk_buff *ctrl_build_family_msg(struct genl_family *family,
680 u32 pid, int seq, u8 cmd)
685 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
687 return ERR_PTR(-ENOBUFS);
689 err = ctrl_fill_info(family, pid, seq, 0, skb, cmd);
698 static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_multicast_group *grp,
699 u32 pid, int seq, u8 cmd)
704 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
706 return ERR_PTR(-ENOBUFS);
708 err = ctrl_fill_mcgrp_info(grp, pid, seq, 0, skb, cmd);
717 static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
718 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 },
719 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
720 .len = GENL_NAMSIZ - 1 },
723 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
726 struct genl_family *res = NULL;
729 if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
730 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
731 res = genl_family_find_byid(id);
734 if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
737 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
738 res = genl_family_find_byname(name);
746 msg = ctrl_build_family_msg(res, info->snd_pid, info->snd_seq,
753 err = genlmsg_reply(msg, info);
758 static int genl_ctrl_event(int event, void *data)
762 if (genl_sock == NULL)
766 case CTRL_CMD_NEWFAMILY:
767 case CTRL_CMD_DELFAMILY:
768 msg = ctrl_build_family_msg(data, 0, 0, event);
772 genlmsg_multicast(msg, 0, GENL_ID_CTRL, GFP_KERNEL);
774 case CTRL_CMD_NEWMCAST_GRP:
775 case CTRL_CMD_DELMCAST_GRP:
776 msg = ctrl_build_mcgrp_msg(data, 0, 0, event);
780 genlmsg_multicast(msg, 0, GENL_ID_CTRL, GFP_KERNEL);
787 static struct genl_ops genl_ctrl_ops = {
788 .cmd = CTRL_CMD_GETFAMILY,
789 .doit = ctrl_getfamily,
790 .dumpit = ctrl_dumpfamily,
791 .policy = ctrl_policy,
794 static struct genl_multicast_group notify_grp = {
798 static int __init genl_init(void)
802 for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
803 INIT_LIST_HEAD(&family_ht[i]);
805 err = genl_register_family(&genl_ctrl);
809 err = genl_register_ops(&genl_ctrl, &genl_ctrl_ops);
811 goto errout_register;
813 netlink_set_nonroot(NETLINK_GENERIC, NL_NONROOT_RECV);
815 /* we'll bump the group number right afterwards */
816 genl_sock = netlink_kernel_create(&init_net, NETLINK_GENERIC, 0,
817 genl_rcv, &genl_mutex, THIS_MODULE);
818 if (genl_sock == NULL)
819 panic("GENL: Cannot initialize generic netlink\n");
821 err = genl_register_mc_group(&genl_ctrl, ¬ify_grp);
823 goto errout_register;
828 genl_unregister_family(&genl_ctrl);
830 panic("GENL: Cannot register controller: %d\n", err);
833 subsys_initcall(genl_init);
835 EXPORT_SYMBOL(genl_sock);
836 EXPORT_SYMBOL(genl_register_ops);
837 EXPORT_SYMBOL(genl_unregister_ops);
838 EXPORT_SYMBOL(genl_register_family);
839 EXPORT_SYMBOL(genl_unregister_family);