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 static DEFINE_MUTEX(genl_mutex
); /* serialization of message processing */
23 static inline void genl_lock(void)
25 mutex_lock(&genl_mutex
);
28 static inline void genl_unlock(void)
30 mutex_unlock(&genl_mutex
);
33 #define GENL_FAM_TAB_SIZE 16
34 #define GENL_FAM_TAB_MASK (GENL_FAM_TAB_SIZE - 1)
36 static struct list_head family_ht
[GENL_FAM_TAB_SIZE
];
38 * Bitmap of multicast groups that are currently in use.
40 * To avoid an allocation at boot of just one unsigned long,
41 * declare it global instead.
42 * Bit 0 is marked as already used since group 0 is invalid.
44 static unsigned long mc_group_start
= 0x1;
45 static unsigned long *mc_groups
= &mc_group_start
;
46 static unsigned long mc_groups_longs
= 1;
48 static int genl_ctrl_event(int event
, void *data
);
50 static inline unsigned int genl_family_hash(unsigned int id
)
52 return id
& GENL_FAM_TAB_MASK
;
55 static inline struct list_head
*genl_family_chain(unsigned int id
)
57 return &family_ht
[genl_family_hash(id
)];
60 static struct genl_family
*genl_family_find_byid(unsigned int id
)
62 struct genl_family
*f
;
64 list_for_each_entry(f
, genl_family_chain(id
), family_list
)
71 static struct genl_family
*genl_family_find_byname(char *name
)
73 struct genl_family
*f
;
76 for (i
= 0; i
< GENL_FAM_TAB_SIZE
; i
++)
77 list_for_each_entry(f
, genl_family_chain(i
), family_list
)
78 if (strcmp(f
->name
, name
) == 0)
84 static struct genl_ops
*genl_get_cmd(u8 cmd
, struct genl_family
*family
)
88 list_for_each_entry(ops
, &family
->ops_list
, ops_list
)
95 /* Of course we are going to have problems once we hit
96 * 2^16 alive types, but that can only happen by year 2K
98 static inline u16
genl_generate_id(void)
100 static u16 id_gen_idx
;
105 id_gen_idx
= GENL_MIN_ID
;
107 if (++id_gen_idx
> GENL_MAX_ID
) {
116 } while (genl_family_find_byid(id_gen_idx
));
121 static struct genl_multicast_group notify_grp
;
124 * genl_register_mc_group - register a multicast group
126 * Registers the specified multicast group and notifies userspace
127 * about the new group.
129 * Returns 0 on success or a negative error code.
131 * @family: The generic netlink family the group shall be registered for.
132 * @grp: The group to register, must have a name.
134 int genl_register_mc_group(struct genl_family
*family
,
135 struct genl_multicast_group
*grp
)
138 unsigned long *new_groups
;
141 BUG_ON(grp
->name
[0] == '\0');
145 /* special-case our own group */
146 if (grp
== ¬ify_grp
)
149 id
= find_first_zero_bit(mc_groups
,
150 mc_groups_longs
* BITS_PER_LONG
);
153 if (id
>= mc_groups_longs
* BITS_PER_LONG
) {
154 size_t nlen
= (mc_groups_longs
+ 1) * sizeof(unsigned long);
156 if (mc_groups
== &mc_group_start
) {
157 new_groups
= kzalloc(nlen
, GFP_KERNEL
);
162 mc_groups
= new_groups
;
163 *mc_groups
= mc_group_start
;
165 new_groups
= krealloc(mc_groups
, nlen
, GFP_KERNEL
);
170 mc_groups
= new_groups
;
171 mc_groups
[mc_groups_longs
] = 0;
176 if (family
->netnsok
) {
179 netlink_table_grab();
181 for_each_net_rcu(net
) {
182 err
= __netlink_change_ngroups(net
->genl_sock
,
183 mc_groups_longs
* BITS_PER_LONG
);
186 * No need to roll back, can only fail if
187 * memory allocation fails and then the
188 * number of _possible_ groups has been
189 * increased on some sockets which is ok.
192 netlink_table_ungrab();
197 netlink_table_ungrab();
199 err
= netlink_change_ngroups(init_net
.genl_sock
,
200 mc_groups_longs
* BITS_PER_LONG
);
206 set_bit(id
, mc_groups
);
207 list_add_tail(&grp
->list
, &family
->mcast_groups
);
208 grp
->family
= family
;
210 genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP
, grp
);
215 EXPORT_SYMBOL(genl_register_mc_group
);
217 static void __genl_unregister_mc_group(struct genl_family
*family
,
218 struct genl_multicast_group
*grp
)
221 BUG_ON(grp
->family
!= family
);
224 for_each_net_rcu(net
)
225 netlink_clear_multicast_users(net
->genl_sock
, grp
->id
);
228 clear_bit(grp
->id
, mc_groups
);
229 list_del(&grp
->list
);
230 genl_ctrl_event(CTRL_CMD_DELMCAST_GRP
, grp
);
236 * genl_unregister_mc_group - unregister a multicast group
238 * Unregisters the specified multicast group and notifies userspace
239 * about it. All current listeners on the group are removed.
241 * Note: It is not necessary to unregister all multicast groups before
242 * unregistering the family, unregistering the family will cause
243 * all assigned multicast groups to be unregistered automatically.
245 * @family: Generic netlink family the group belongs to.
246 * @grp: The group to unregister, must have been registered successfully
249 void genl_unregister_mc_group(struct genl_family
*family
,
250 struct genl_multicast_group
*grp
)
253 __genl_unregister_mc_group(family
, grp
);
256 EXPORT_SYMBOL(genl_unregister_mc_group
);
258 static void genl_unregister_mc_groups(struct genl_family
*family
)
260 struct genl_multicast_group
*grp
, *tmp
;
262 list_for_each_entry_safe(grp
, tmp
, &family
->mcast_groups
, list
)
263 __genl_unregister_mc_group(family
, grp
);
267 * genl_register_ops - register generic netlink operations
268 * @family: generic netlink family
269 * @ops: operations to be registered
271 * Registers the specified operations and assigns them to the specified
272 * family. Either a doit or dumpit callback must be specified or the
273 * operation will fail. Only one operation structure per command
274 * identifier may be registered.
276 * See include/net/genetlink.h for more documenation on the operations
279 * Returns 0 on success or a negative error code.
281 int genl_register_ops(struct genl_family
*family
, struct genl_ops
*ops
)
285 if (ops
->dumpit
== NULL
&& ops
->doit
== NULL
)
288 if (genl_get_cmd(ops
->cmd
, family
)) {
294 ops
->flags
|= GENL_CMD_CAP_DUMP
;
296 ops
->flags
|= GENL_CMD_CAP_DO
;
298 ops
->flags
|= GENL_CMD_CAP_HASPOL
;
301 list_add_tail(&ops
->ops_list
, &family
->ops_list
);
304 genl_ctrl_event(CTRL_CMD_NEWOPS
, ops
);
311 * genl_unregister_ops - unregister generic netlink operations
312 * @family: generic netlink family
313 * @ops: operations to be unregistered
315 * Unregisters the specified operations and unassigns them from the
316 * specified family. The operation blocks until the current message
317 * processing has finished and doesn't start again until the
318 * unregister process has finished.
320 * Note: It is not necessary to unregister all operations before
321 * unregistering the family, unregistering the family will cause
322 * all assigned operations to be unregistered automatically.
324 * Returns 0 on success or a negative error code.
326 int genl_unregister_ops(struct genl_family
*family
, struct genl_ops
*ops
)
331 list_for_each_entry(rc
, &family
->ops_list
, ops_list
) {
333 list_del(&ops
->ops_list
);
335 genl_ctrl_event(CTRL_CMD_DELOPS
, ops
);
345 * genl_register_family - register a generic netlink family
346 * @family: generic netlink family
348 * Registers the specified family after validating it first. Only one
349 * family may be registered with the same family name or identifier.
350 * The family id may equal GENL_ID_GENERATE causing an unique id to
351 * be automatically generated and assigned.
353 * Return 0 on success or a negative error code.
355 int genl_register_family(struct genl_family
*family
)
359 if (family
->id
&& family
->id
< GENL_MIN_ID
)
362 if (family
->id
> GENL_MAX_ID
)
365 INIT_LIST_HEAD(&family
->ops_list
);
366 INIT_LIST_HEAD(&family
->mcast_groups
);
370 if (genl_family_find_byname(family
->name
)) {
375 if (genl_family_find_byid(family
->id
)) {
380 if (family
->id
== GENL_ID_GENERATE
) {
381 u16 newid
= genl_generate_id();
391 if (family
->maxattr
) {
392 family
->attrbuf
= kmalloc((family
->maxattr
+1) *
393 sizeof(struct nlattr
*), GFP_KERNEL
);
394 if (family
->attrbuf
== NULL
) {
399 family
->attrbuf
= NULL
;
401 list_add_tail(&family
->family_list
, genl_family_chain(family
->id
));
404 genl_ctrl_event(CTRL_CMD_NEWFAMILY
, family
);
415 * genl_register_family_with_ops - register a generic netlink family
416 * @family: generic netlink family
417 * @ops: operations to be registered
418 * @n_ops: number of elements to register
420 * Registers the specified family and operations from the specified table.
421 * Only one family may be registered with the same family name or identifier.
423 * The family id may equal GENL_ID_GENERATE causing an unique id to
424 * be automatically generated and assigned.
426 * Either a doit or dumpit callback must be specified for every registered
427 * operation or the function will fail. Only one operation structure per
428 * command identifier may be registered.
430 * See include/net/genetlink.h for more documenation on the operations
433 * This is equivalent to calling genl_register_family() followed by
434 * genl_register_ops() for every operation entry in the table taking
435 * care to unregister the family on error path.
437 * Return 0 on success or a negative error code.
439 int genl_register_family_with_ops(struct genl_family
*family
,
440 struct genl_ops
*ops
, size_t n_ops
)
444 err
= genl_register_family(family
);
448 for (i
= 0; i
< n_ops
; ++i
, ++ops
) {
449 err
= genl_register_ops(family
, ops
);
455 genl_unregister_family(family
);
458 EXPORT_SYMBOL(genl_register_family_with_ops
);
461 * genl_unregister_family - unregister generic netlink family
462 * @family: generic netlink family
464 * Unregisters the specified family.
466 * Returns 0 on success or a negative error code.
468 int genl_unregister_family(struct genl_family
*family
)
470 struct genl_family
*rc
;
474 genl_unregister_mc_groups(family
);
476 list_for_each_entry(rc
, genl_family_chain(family
->id
), family_list
) {
477 if (family
->id
!= rc
->id
|| strcmp(rc
->name
, family
->name
))
480 list_del(&rc
->family_list
);
481 INIT_LIST_HEAD(&family
->ops_list
);
484 kfree(family
->attrbuf
);
485 genl_ctrl_event(CTRL_CMD_DELFAMILY
, family
);
494 static int genl_rcv_msg(struct sk_buff
*skb
, struct nlmsghdr
*nlh
)
496 struct genl_ops
*ops
;
497 struct genl_family
*family
;
498 struct net
*net
= sock_net(skb
->sk
);
499 struct genl_info info
;
500 struct genlmsghdr
*hdr
= nlmsg_data(nlh
);
503 family
= genl_family_find_byid(nlh
->nlmsg_type
);
507 /* this family doesn't exist in this netns */
508 if (!family
->netnsok
&& !net_eq(net
, &init_net
))
511 hdrlen
= GENL_HDRLEN
+ family
->hdrsize
;
512 if (nlh
->nlmsg_len
< nlmsg_msg_size(hdrlen
))
515 ops
= genl_get_cmd(hdr
->cmd
, family
);
519 if ((ops
->flags
& GENL_ADMIN_PERM
) &&
520 security_netlink_recv(skb
, CAP_NET_ADMIN
))
523 if (nlh
->nlmsg_flags
& NLM_F_DUMP
) {
524 if (ops
->dumpit
== NULL
)
528 err
= netlink_dump_start(net
->genl_sock
, skb
, nlh
,
529 ops
->dumpit
, ops
->done
);
534 if (ops
->doit
== NULL
)
537 if (family
->attrbuf
) {
538 err
= nlmsg_parse(nlh
, hdrlen
, family
->attrbuf
, family
->maxattr
,
544 info
.snd_seq
= nlh
->nlmsg_seq
;
545 info
.snd_pid
= NETLINK_CB(skb
).pid
;
547 info
.genlhdr
= nlmsg_data(nlh
);
548 info
.userhdr
= nlmsg_data(nlh
) + GENL_HDRLEN
;
549 info
.attrs
= family
->attrbuf
;
550 genl_info_net_set(&info
, net
);
552 return ops
->doit(skb
, &info
);
555 static void genl_rcv(struct sk_buff
*skb
)
558 netlink_rcv_skb(skb
, &genl_rcv_msg
);
562 /**************************************************************************
564 **************************************************************************/
566 static struct genl_family genl_ctrl
= {
570 .maxattr
= CTRL_ATTR_MAX
,
574 static int ctrl_fill_info(struct genl_family
*family
, u32 pid
, u32 seq
,
575 u32 flags
, struct sk_buff
*skb
, u8 cmd
)
579 hdr
= genlmsg_put(skb
, pid
, seq
, &genl_ctrl
, flags
, cmd
);
583 NLA_PUT_STRING(skb
, CTRL_ATTR_FAMILY_NAME
, family
->name
);
584 NLA_PUT_U16(skb
, CTRL_ATTR_FAMILY_ID
, family
->id
);
585 NLA_PUT_U32(skb
, CTRL_ATTR_VERSION
, family
->version
);
586 NLA_PUT_U32(skb
, CTRL_ATTR_HDRSIZE
, family
->hdrsize
);
587 NLA_PUT_U32(skb
, CTRL_ATTR_MAXATTR
, family
->maxattr
);
589 if (!list_empty(&family
->ops_list
)) {
590 struct nlattr
*nla_ops
;
591 struct genl_ops
*ops
;
594 nla_ops
= nla_nest_start(skb
, CTRL_ATTR_OPS
);
596 goto nla_put_failure
;
598 list_for_each_entry(ops
, &family
->ops_list
, ops_list
) {
601 nest
= nla_nest_start(skb
, idx
++);
603 goto nla_put_failure
;
605 NLA_PUT_U32(skb
, CTRL_ATTR_OP_ID
, ops
->cmd
);
606 NLA_PUT_U32(skb
, CTRL_ATTR_OP_FLAGS
, ops
->flags
);
608 nla_nest_end(skb
, nest
);
611 nla_nest_end(skb
, nla_ops
);
614 if (!list_empty(&family
->mcast_groups
)) {
615 struct genl_multicast_group
*grp
;
616 struct nlattr
*nla_grps
;
619 nla_grps
= nla_nest_start(skb
, CTRL_ATTR_MCAST_GROUPS
);
620 if (nla_grps
== NULL
)
621 goto nla_put_failure
;
623 list_for_each_entry(grp
, &family
->mcast_groups
, list
) {
626 nest
= nla_nest_start(skb
, idx
++);
628 goto nla_put_failure
;
630 NLA_PUT_U32(skb
, CTRL_ATTR_MCAST_GRP_ID
, grp
->id
);
631 NLA_PUT_STRING(skb
, CTRL_ATTR_MCAST_GRP_NAME
,
634 nla_nest_end(skb
, nest
);
636 nla_nest_end(skb
, nla_grps
);
639 return genlmsg_end(skb
, hdr
);
642 genlmsg_cancel(skb
, hdr
);
646 static int ctrl_fill_mcgrp_info(struct genl_multicast_group
*grp
, u32 pid
,
647 u32 seq
, u32 flags
, struct sk_buff
*skb
,
651 struct nlattr
*nla_grps
;
654 hdr
= genlmsg_put(skb
, pid
, seq
, &genl_ctrl
, flags
, cmd
);
658 NLA_PUT_STRING(skb
, CTRL_ATTR_FAMILY_NAME
, grp
->family
->name
);
659 NLA_PUT_U16(skb
, CTRL_ATTR_FAMILY_ID
, grp
->family
->id
);
661 nla_grps
= nla_nest_start(skb
, CTRL_ATTR_MCAST_GROUPS
);
662 if (nla_grps
== NULL
)
663 goto nla_put_failure
;
665 nest
= nla_nest_start(skb
, 1);
667 goto nla_put_failure
;
669 NLA_PUT_U32(skb
, CTRL_ATTR_MCAST_GRP_ID
, grp
->id
);
670 NLA_PUT_STRING(skb
, CTRL_ATTR_MCAST_GRP_NAME
,
673 nla_nest_end(skb
, nest
);
674 nla_nest_end(skb
, nla_grps
);
676 return genlmsg_end(skb
, hdr
);
679 genlmsg_cancel(skb
, hdr
);
683 static int ctrl_dumpfamily(struct sk_buff
*skb
, struct netlink_callback
*cb
)
687 struct genl_family
*rt
;
688 struct net
*net
= sock_net(skb
->sk
);
689 int chains_to_skip
= cb
->args
[0];
690 int fams_to_skip
= cb
->args
[1];
692 for (i
= 0; i
< GENL_FAM_TAB_SIZE
; i
++) {
693 if (i
< chains_to_skip
)
696 list_for_each_entry(rt
, genl_family_chain(i
), family_list
) {
697 if (!rt
->netnsok
&& !net_eq(net
, &init_net
))
699 if (++n
< fams_to_skip
)
701 if (ctrl_fill_info(rt
, NETLINK_CB(cb
->skb
).pid
,
702 cb
->nlh
->nlmsg_seq
, NLM_F_MULTI
,
703 skb
, CTRL_CMD_NEWFAMILY
) < 0)
717 static struct sk_buff
*ctrl_build_family_msg(struct genl_family
*family
,
718 u32 pid
, int seq
, u8 cmd
)
723 skb
= nlmsg_new(NLMSG_DEFAULT_SIZE
, GFP_KERNEL
);
725 return ERR_PTR(-ENOBUFS
);
727 err
= ctrl_fill_info(family
, pid
, seq
, 0, skb
, cmd
);
736 static struct sk_buff
*ctrl_build_mcgrp_msg(struct genl_multicast_group
*grp
,
737 u32 pid
, int seq
, u8 cmd
)
742 skb
= nlmsg_new(NLMSG_DEFAULT_SIZE
, GFP_KERNEL
);
744 return ERR_PTR(-ENOBUFS
);
746 err
= ctrl_fill_mcgrp_info(grp
, pid
, seq
, 0, skb
, cmd
);
755 static const struct nla_policy ctrl_policy
[CTRL_ATTR_MAX
+1] = {
756 [CTRL_ATTR_FAMILY_ID
] = { .type
= NLA_U16
},
757 [CTRL_ATTR_FAMILY_NAME
] = { .type
= NLA_NUL_STRING
,
758 .len
= GENL_NAMSIZ
- 1 },
761 static int ctrl_getfamily(struct sk_buff
*skb
, struct genl_info
*info
)
764 struct genl_family
*res
= NULL
;
767 if (info
->attrs
[CTRL_ATTR_FAMILY_ID
]) {
768 u16 id
= nla_get_u16(info
->attrs
[CTRL_ATTR_FAMILY_ID
]);
769 res
= genl_family_find_byid(id
);
773 if (info
->attrs
[CTRL_ATTR_FAMILY_NAME
]) {
776 name
= nla_data(info
->attrs
[CTRL_ATTR_FAMILY_NAME
]);
777 res
= genl_family_find_byname(name
);
784 if (!res
->netnsok
&& !net_eq(genl_info_net(info
), &init_net
)) {
785 /* family doesn't exist here */
789 msg
= ctrl_build_family_msg(res
, info
->snd_pid
, info
->snd_seq
,
794 return genlmsg_reply(msg
, info
);
797 static int genl_ctrl_event(int event
, void *data
)
800 struct genl_family
*family
;
801 struct genl_multicast_group
*grp
;
803 /* genl is still initialising */
804 if (!init_net
.genl_sock
)
808 case CTRL_CMD_NEWFAMILY
:
809 case CTRL_CMD_DELFAMILY
:
811 msg
= ctrl_build_family_msg(family
, 0, 0, event
);
813 case CTRL_CMD_NEWMCAST_GRP
:
814 case CTRL_CMD_DELMCAST_GRP
:
816 family
= grp
->family
;
817 msg
= ctrl_build_mcgrp_msg(data
, 0, 0, event
);
826 if (!family
->netnsok
) {
827 genlmsg_multicast_netns(&init_net
, msg
, 0,
828 GENL_ID_CTRL
, GFP_KERNEL
);
831 genlmsg_multicast_allns(msg
, 0, GENL_ID_CTRL
, GFP_ATOMIC
);
838 static struct genl_ops genl_ctrl_ops
= {
839 .cmd
= CTRL_CMD_GETFAMILY
,
840 .doit
= ctrl_getfamily
,
841 .dumpit
= ctrl_dumpfamily
,
842 .policy
= ctrl_policy
,
845 static struct genl_multicast_group notify_grp
= {
849 static int __net_init
genl_pernet_init(struct net
*net
)
851 /* we'll bump the group number right afterwards */
852 net
->genl_sock
= netlink_kernel_create(net
, NETLINK_GENERIC
, 0,
853 genl_rcv
, &genl_mutex
,
856 if (!net
->genl_sock
&& net_eq(net
, &init_net
))
857 panic("GENL: Cannot initialize generic netlink\n");
865 static void __net_exit
genl_pernet_exit(struct net
*net
)
867 netlink_kernel_release(net
->genl_sock
);
868 net
->genl_sock
= NULL
;
871 static struct pernet_operations genl_pernet_ops
= {
872 .init
= genl_pernet_init
,
873 .exit
= genl_pernet_exit
,
876 static int __init
genl_init(void)
880 for (i
= 0; i
< GENL_FAM_TAB_SIZE
; i
++)
881 INIT_LIST_HEAD(&family_ht
[i
]);
883 err
= genl_register_family(&genl_ctrl
);
887 err
= genl_register_ops(&genl_ctrl
, &genl_ctrl_ops
);
891 netlink_set_nonroot(NETLINK_GENERIC
, NL_NONROOT_RECV
);
893 err
= register_pernet_subsys(&genl_pernet_ops
);
897 err
= genl_register_mc_group(&genl_ctrl
, ¬ify_grp
);
904 panic("GENL: Cannot register controller: %d\n", err
);
907 subsys_initcall(genl_init
);
909 EXPORT_SYMBOL(genl_register_ops
);
910 EXPORT_SYMBOL(genl_unregister_ops
);
911 EXPORT_SYMBOL(genl_register_family
);
912 EXPORT_SYMBOL(genl_unregister_family
);
914 static int genlmsg_mcast(struct sk_buff
*skb
, u32 pid
, unsigned long group
,
918 struct net
*net
, *prev
= NULL
;
921 for_each_net_rcu(net
) {
923 tmp
= skb_clone(skb
, flags
);
928 err
= nlmsg_multicast(prev
->genl_sock
, tmp
,
937 return nlmsg_multicast(prev
->genl_sock
, skb
, pid
, group
, flags
);
943 int genlmsg_multicast_allns(struct sk_buff
*skb
, u32 pid
, unsigned int group
,
946 return genlmsg_mcast(skb
, pid
, group
, flags
);
948 EXPORT_SYMBOL(genlmsg_multicast_allns
);