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_unregister_family - unregister generic netlink family
388 * @family: generic netlink family
390 * Unregisters the specified family.
392 * Returns 0 on success or a negative error code.
394 int genl_unregister_family(struct genl_family *family)
396 struct genl_family *rc;
400 genl_unregister_mc_groups(family);
402 list_for_each_entry(rc, genl_family_chain(family->id), family_list) {
403 if (family->id != rc->id || strcmp(rc->name, family->name))
406 list_del(&rc->family_list);
407 INIT_LIST_HEAD(&family->ops_list);
410 kfree(family->attrbuf);
411 genl_ctrl_event(CTRL_CMD_DELFAMILY, family);
420 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
422 struct genl_ops *ops;
423 struct genl_family *family;
424 struct genl_info info;
425 struct genlmsghdr *hdr = nlmsg_data(nlh);
428 family = genl_family_find_byid(nlh->nlmsg_type);
432 hdrlen = GENL_HDRLEN + family->hdrsize;
433 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
436 ops = genl_get_cmd(hdr->cmd, family);
440 if ((ops->flags & GENL_ADMIN_PERM) &&
441 security_netlink_recv(skb, CAP_NET_ADMIN))
444 if (nlh->nlmsg_flags & NLM_F_DUMP) {
445 if (ops->dumpit == NULL)
449 err = netlink_dump_start(genl_sock, skb, nlh,
450 ops->dumpit, ops->done);
455 if (ops->doit == NULL)
458 if (family->attrbuf) {
459 err = nlmsg_parse(nlh, hdrlen, family->attrbuf, family->maxattr,
465 info.snd_seq = nlh->nlmsg_seq;
466 info.snd_pid = NETLINK_CB(skb).pid;
468 info.genlhdr = nlmsg_data(nlh);
469 info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
470 info.attrs = family->attrbuf;
472 return ops->doit(skb, &info);
475 static void genl_rcv(struct sk_buff *skb)
478 netlink_rcv_skb(skb, &genl_rcv_msg);
482 /**************************************************************************
484 **************************************************************************/
486 static struct genl_family genl_ctrl = {
490 .maxattr = CTRL_ATTR_MAX,
493 static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
494 u32 flags, struct sk_buff *skb, u8 cmd)
498 hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
502 NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, family->name);
503 NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, family->id);
504 NLA_PUT_U32(skb, CTRL_ATTR_VERSION, family->version);
505 NLA_PUT_U32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize);
506 NLA_PUT_U32(skb, CTRL_ATTR_MAXATTR, family->maxattr);
508 if (!list_empty(&family->ops_list)) {
509 struct nlattr *nla_ops;
510 struct genl_ops *ops;
513 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
515 goto nla_put_failure;
517 list_for_each_entry(ops, &family->ops_list, ops_list) {
520 nest = nla_nest_start(skb, idx++);
522 goto nla_put_failure;
524 NLA_PUT_U32(skb, CTRL_ATTR_OP_ID, ops->cmd);
525 NLA_PUT_U32(skb, CTRL_ATTR_OP_FLAGS, ops->flags);
527 nla_nest_end(skb, nest);
530 nla_nest_end(skb, nla_ops);
533 if (!list_empty(&family->mcast_groups)) {
534 struct genl_multicast_group *grp;
535 struct nlattr *nla_grps;
538 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
539 if (nla_grps == NULL)
540 goto nla_put_failure;
542 list_for_each_entry(grp, &family->mcast_groups, list) {
545 nest = nla_nest_start(skb, idx++);
547 goto nla_put_failure;
549 NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
550 NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
553 nla_nest_end(skb, nest);
555 nla_nest_end(skb, nla_grps);
558 return genlmsg_end(skb, hdr);
561 genlmsg_cancel(skb, hdr);
565 static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 pid,
566 u32 seq, u32 flags, struct sk_buff *skb,
570 struct nlattr *nla_grps;
573 hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
577 NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, grp->family->name);
578 NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, grp->family->id);
580 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
581 if (nla_grps == NULL)
582 goto nla_put_failure;
584 nest = nla_nest_start(skb, 1);
586 goto nla_put_failure;
588 NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
589 NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
592 nla_nest_end(skb, nest);
593 nla_nest_end(skb, nla_grps);
595 return genlmsg_end(skb, hdr);
598 genlmsg_cancel(skb, hdr);
602 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
606 struct genl_family *rt;
607 int chains_to_skip = cb->args[0];
608 int fams_to_skip = cb->args[1];
610 for (i = 0; i < GENL_FAM_TAB_SIZE; i++) {
611 if (i < chains_to_skip)
614 list_for_each_entry(rt, genl_family_chain(i), family_list) {
615 if (++n < fams_to_skip)
617 if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).pid,
618 cb->nlh->nlmsg_seq, NLM_F_MULTI,
619 skb, CTRL_CMD_NEWFAMILY) < 0)
633 static struct sk_buff *ctrl_build_family_msg(struct genl_family *family,
634 u32 pid, int seq, u8 cmd)
639 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
641 return ERR_PTR(-ENOBUFS);
643 err = ctrl_fill_info(family, pid, seq, 0, skb, cmd);
652 static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_multicast_group *grp,
653 u32 pid, int seq, u8 cmd)
658 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
660 return ERR_PTR(-ENOBUFS);
662 err = ctrl_fill_mcgrp_info(grp, pid, seq, 0, skb, cmd);
671 static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
672 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 },
673 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
674 .len = GENL_NAMSIZ - 1 },
677 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
680 struct genl_family *res = NULL;
683 if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
684 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
685 res = genl_family_find_byid(id);
688 if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
691 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
692 res = genl_family_find_byname(name);
700 msg = ctrl_build_family_msg(res, info->snd_pid, info->snd_seq,
707 err = genlmsg_reply(msg, info);
712 static int genl_ctrl_event(int event, void *data)
716 if (genl_sock == NULL)
720 case CTRL_CMD_NEWFAMILY:
721 case CTRL_CMD_DELFAMILY:
722 msg = ctrl_build_family_msg(data, 0, 0, event);
726 genlmsg_multicast(msg, 0, GENL_ID_CTRL, GFP_KERNEL);
728 case CTRL_CMD_NEWMCAST_GRP:
729 case CTRL_CMD_DELMCAST_GRP:
730 msg = ctrl_build_mcgrp_msg(data, 0, 0, event);
734 genlmsg_multicast(msg, 0, GENL_ID_CTRL, GFP_KERNEL);
741 static struct genl_ops genl_ctrl_ops = {
742 .cmd = CTRL_CMD_GETFAMILY,
743 .doit = ctrl_getfamily,
744 .dumpit = ctrl_dumpfamily,
745 .policy = ctrl_policy,
748 static struct genl_multicast_group notify_grp = {
752 static int __init genl_init(void)
756 for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
757 INIT_LIST_HEAD(&family_ht[i]);
759 err = genl_register_family(&genl_ctrl);
763 err = genl_register_ops(&genl_ctrl, &genl_ctrl_ops);
765 goto errout_register;
767 netlink_set_nonroot(NETLINK_GENERIC, NL_NONROOT_RECV);
769 /* we'll bump the group number right afterwards */
770 genl_sock = netlink_kernel_create(&init_net, NETLINK_GENERIC, 0,
771 genl_rcv, &genl_mutex, THIS_MODULE);
772 if (genl_sock == NULL)
773 panic("GENL: Cannot initialize generic netlink\n");
775 err = genl_register_mc_group(&genl_ctrl, ¬ify_grp);
777 goto errout_register;
782 genl_unregister_family(&genl_ctrl);
784 panic("GENL: Cannot register controller: %d\n", err);
787 subsys_initcall(genl_init);
789 EXPORT_SYMBOL(genl_sock);
790 EXPORT_SYMBOL(genl_register_ops);
791 EXPORT_SYMBOL(genl_unregister_ops);
792 EXPORT_SYMBOL(genl_register_family);
793 EXPORT_SYMBOL(genl_unregister_family);