bluetooth: hid: make Android code conditional
[linux-2.6.git] / net / netlink / genetlink.c
1 /*
2  * NETLINK      Generic Netlink Family
3  *
4  *              Authors:        Jamal Hadi Salim
5  *                              Thomas Graf <tgraf@suug.ch>
6  *                              Johannes Berg <johannes@sipsolutions.net>
7  */
8
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>
19 #include <net/sock.h>
20 #include <net/genetlink.h>
21
22 static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */
23
24 void genl_lock(void)
25 {
26         mutex_lock(&genl_mutex);
27 }
28 EXPORT_SYMBOL(genl_lock);
29
30 void genl_unlock(void)
31 {
32         mutex_unlock(&genl_mutex);
33 }
34 EXPORT_SYMBOL(genl_unlock);
35
36 #define GENL_FAM_TAB_SIZE       16
37 #define GENL_FAM_TAB_MASK       (GENL_FAM_TAB_SIZE - 1)
38
39 static struct list_head family_ht[GENL_FAM_TAB_SIZE];
40 /*
41  * Bitmap of multicast groups that are currently in use.
42  *
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.
46  */
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;
50
51 static int genl_ctrl_event(int event, void *data);
52
53 static inline unsigned int genl_family_hash(unsigned int id)
54 {
55         return id & GENL_FAM_TAB_MASK;
56 }
57
58 static inline struct list_head *genl_family_chain(unsigned int id)
59 {
60         return &family_ht[genl_family_hash(id)];
61 }
62
63 static struct genl_family *genl_family_find_byid(unsigned int id)
64 {
65         struct genl_family *f;
66
67         list_for_each_entry(f, genl_family_chain(id), family_list)
68                 if (f->id == id)
69                         return f;
70
71         return NULL;
72 }
73
74 static struct genl_family *genl_family_find_byname(char *name)
75 {
76         struct genl_family *f;
77         int i;
78
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)
82                                 return f;
83
84         return NULL;
85 }
86
87 static struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family)
88 {
89         struct genl_ops *ops;
90
91         list_for_each_entry(ops, &family->ops_list, ops_list)
92                 if (ops->cmd == cmd)
93                         return ops;
94
95         return NULL;
96 }
97
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
100 */
101 static inline u16 genl_generate_id(void)
102 {
103         static u16 id_gen_idx = GENL_MIN_ID;
104         int i;
105
106         for (i = 0; i <= GENL_MAX_ID - GENL_MIN_ID; i++) {
107                 if (!genl_family_find_byid(id_gen_idx))
108                         return id_gen_idx;
109                 if (++id_gen_idx > GENL_MAX_ID)
110                         id_gen_idx = GENL_MIN_ID;
111         }
112
113         return 0;
114 }
115
116 static struct genl_multicast_group notify_grp;
117
118 /**
119  * genl_register_mc_group - register a multicast group
120  *
121  * Registers the specified multicast group and notifies userspace
122  * about the new group.
123  *
124  * Returns 0 on success or a negative error code.
125  *
126  * @family: The generic netlink family the group shall be registered for.
127  * @grp: The group to register, must have a name.
128  */
129 int genl_register_mc_group(struct genl_family *family,
130                            struct genl_multicast_group *grp)
131 {
132         int id;
133         unsigned long *new_groups;
134         int err = 0;
135
136         BUG_ON(grp->name[0] == '\0');
137
138         genl_lock();
139
140         /* special-case our own group */
141         if (grp == &notify_grp)
142                 id = GENL_ID_CTRL;
143         else
144                 id = find_first_zero_bit(mc_groups,
145                                          mc_groups_longs * BITS_PER_LONG);
146
147
148         if (id >= mc_groups_longs * BITS_PER_LONG) {
149                 size_t nlen = (mc_groups_longs + 1) * sizeof(unsigned long);
150
151                 if (mc_groups == &mc_group_start) {
152                         new_groups = kzalloc(nlen, GFP_KERNEL);
153                         if (!new_groups) {
154                                 err = -ENOMEM;
155                                 goto out;
156                         }
157                         mc_groups = new_groups;
158                         *mc_groups = mc_group_start;
159                 } else {
160                         new_groups = krealloc(mc_groups, nlen, GFP_KERNEL);
161                         if (!new_groups) {
162                                 err = -ENOMEM;
163                                 goto out;
164                         }
165                         mc_groups = new_groups;
166                         mc_groups[mc_groups_longs] = 0;
167                 }
168                 mc_groups_longs++;
169         }
170
171         if (family->netnsok) {
172                 struct net *net;
173
174                 netlink_table_grab();
175                 rcu_read_lock();
176                 for_each_net_rcu(net) {
177                         err = __netlink_change_ngroups(net->genl_sock,
178                                         mc_groups_longs * BITS_PER_LONG);
179                         if (err) {
180                                 /*
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.
185                                  */
186                                 rcu_read_unlock();
187                                 netlink_table_ungrab();
188                                 goto out;
189                         }
190                 }
191                 rcu_read_unlock();
192                 netlink_table_ungrab();
193         } else {
194                 err = netlink_change_ngroups(init_net.genl_sock,
195                                              mc_groups_longs * BITS_PER_LONG);
196                 if (err)
197                         goto out;
198         }
199
200         grp->id = id;
201         set_bit(id, mc_groups);
202         list_add_tail(&grp->list, &family->mcast_groups);
203         grp->family = family;
204
205         genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, grp);
206  out:
207         genl_unlock();
208         return err;
209 }
210 EXPORT_SYMBOL(genl_register_mc_group);
211
212 static void __genl_unregister_mc_group(struct genl_family *family,
213                                        struct genl_multicast_group *grp)
214 {
215         struct net *net;
216         BUG_ON(grp->family != family);
217
218         netlink_table_grab();
219         rcu_read_lock();
220         for_each_net_rcu(net)
221                 __netlink_clear_multicast_users(net->genl_sock, grp->id);
222         rcu_read_unlock();
223         netlink_table_ungrab();
224
225         clear_bit(grp->id, mc_groups);
226         list_del(&grp->list);
227         genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, grp);
228         grp->id = 0;
229         grp->family = NULL;
230 }
231
232 /**
233  * genl_unregister_mc_group - unregister a multicast group
234  *
235  * Unregisters the specified multicast group and notifies userspace
236  * about it. All current listeners on the group are removed.
237  *
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.
241  *
242  * @family: Generic netlink family the group belongs to.
243  * @grp: The group to unregister, must have been registered successfully
244  *       previously.
245  */
246 void genl_unregister_mc_group(struct genl_family *family,
247                               struct genl_multicast_group *grp)
248 {
249         genl_lock();
250         __genl_unregister_mc_group(family, grp);
251         genl_unlock();
252 }
253 EXPORT_SYMBOL(genl_unregister_mc_group);
254
255 static void genl_unregister_mc_groups(struct genl_family *family)
256 {
257         struct genl_multicast_group *grp, *tmp;
258
259         list_for_each_entry_safe(grp, tmp, &family->mcast_groups, list)
260                 __genl_unregister_mc_group(family, grp);
261 }
262
263 /**
264  * genl_register_ops - register generic netlink operations
265  * @family: generic netlink family
266  * @ops: operations to be registered
267  *
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.
272  *
273  * See include/net/genetlink.h for more documenation on the operations
274  * structure.
275  *
276  * Returns 0 on success or a negative error code.
277  */
278 int genl_register_ops(struct genl_family *family, struct genl_ops *ops)
279 {
280         int err = -EINVAL;
281
282         if (ops->dumpit == NULL && ops->doit == NULL)
283                 goto errout;
284
285         if (genl_get_cmd(ops->cmd, family)) {
286                 err = -EEXIST;
287                 goto errout;
288         }
289
290         if (ops->dumpit)
291                 ops->flags |= GENL_CMD_CAP_DUMP;
292         if (ops->doit)
293                 ops->flags |= GENL_CMD_CAP_DO;
294         if (ops->policy)
295                 ops->flags |= GENL_CMD_CAP_HASPOL;
296
297         genl_lock();
298         list_add_tail(&ops->ops_list, &family->ops_list);
299         genl_unlock();
300
301         genl_ctrl_event(CTRL_CMD_NEWOPS, ops);
302         err = 0;
303 errout:
304         return err;
305 }
306 EXPORT_SYMBOL(genl_register_ops);
307
308 /**
309  * genl_unregister_ops - unregister generic netlink operations
310  * @family: generic netlink family
311  * @ops: operations to be unregistered
312  *
313  * Unregisters the specified operations and unassigns them from the
314  * specified family. The operation blocks until the current message
315  * processing has finished and doesn't start again until the
316  * unregister process has finished.
317  *
318  * Note: It is not necessary to unregister all operations before
319  *       unregistering the family, unregistering the family will cause
320  *       all assigned operations to be unregistered automatically.
321  *
322  * Returns 0 on success or a negative error code.
323  */
324 int genl_unregister_ops(struct genl_family *family, struct genl_ops *ops)
325 {
326         struct genl_ops *rc;
327
328         genl_lock();
329         list_for_each_entry(rc, &family->ops_list, ops_list) {
330                 if (rc == ops) {
331                         list_del(&ops->ops_list);
332                         genl_unlock();
333                         genl_ctrl_event(CTRL_CMD_DELOPS, ops);
334                         return 0;
335                 }
336         }
337         genl_unlock();
338
339         return -ENOENT;
340 }
341 EXPORT_SYMBOL(genl_unregister_ops);
342
343 /**
344  * genl_register_family - register a generic netlink family
345  * @family: generic netlink family
346  *
347  * Registers the specified family after validating it first. Only one
348  * family may be registered with the same family name or identifier.
349  * The family id may equal GENL_ID_GENERATE causing an unique id to
350  * be automatically generated and assigned.
351  *
352  * Return 0 on success or a negative error code.
353  */
354 int genl_register_family(struct genl_family *family)
355 {
356         int err = -EINVAL;
357
358         if (family->id && family->id < GENL_MIN_ID)
359                 goto errout;
360
361         if (family->id > GENL_MAX_ID)
362                 goto errout;
363
364         INIT_LIST_HEAD(&family->ops_list);
365         INIT_LIST_HEAD(&family->mcast_groups);
366
367         genl_lock();
368
369         if (genl_family_find_byname(family->name)) {
370                 err = -EEXIST;
371                 goto errout_locked;
372         }
373
374         if (family->id == GENL_ID_GENERATE) {
375                 u16 newid = genl_generate_id();
376
377                 if (!newid) {
378                         err = -ENOMEM;
379                         goto errout_locked;
380                 }
381
382                 family->id = newid;
383         } else if (genl_family_find_byid(family->id)) {
384                 err = -EEXIST;
385                 goto errout_locked;
386         }
387
388         if (family->maxattr) {
389                 family->attrbuf = kmalloc((family->maxattr+1) *
390                                         sizeof(struct nlattr *), GFP_KERNEL);
391                 if (family->attrbuf == NULL) {
392                         err = -ENOMEM;
393                         goto errout_locked;
394                 }
395         } else
396                 family->attrbuf = NULL;
397
398         list_add_tail(&family->family_list, genl_family_chain(family->id));
399         genl_unlock();
400
401         genl_ctrl_event(CTRL_CMD_NEWFAMILY, family);
402
403         return 0;
404
405 errout_locked:
406         genl_unlock();
407 errout:
408         return err;
409 }
410 EXPORT_SYMBOL(genl_register_family);
411
412 /**
413  * genl_register_family_with_ops - register a generic netlink family
414  * @family: generic netlink family
415  * @ops: operations to be registered
416  * @n_ops: number of elements to register
417  *
418  * Registers the specified family and operations from the specified table.
419  * Only one family may be registered with the same family name or identifier.
420  *
421  * The family id may equal GENL_ID_GENERATE causing an unique id to
422  * be automatically generated and assigned.
423  *
424  * Either a doit or dumpit callback must be specified for every registered
425  * operation or the function will fail. Only one operation structure per
426  * command identifier may be registered.
427  *
428  * See include/net/genetlink.h for more documenation on the operations
429  * structure.
430  *
431  * This is equivalent to calling genl_register_family() followed by
432  * genl_register_ops() for every operation entry in the table taking
433  * care to unregister the family on error path.
434  *
435  * Return 0 on success or a negative error code.
436  */
437 int genl_register_family_with_ops(struct genl_family *family,
438         struct genl_ops *ops, size_t n_ops)
439 {
440         int err, i;
441
442         err = genl_register_family(family);
443         if (err)
444                 return err;
445
446         for (i = 0; i < n_ops; ++i, ++ops) {
447                 err = genl_register_ops(family, ops);
448                 if (err)
449                         goto err_out;
450         }
451         return 0;
452 err_out:
453         genl_unregister_family(family);
454         return err;
455 }
456 EXPORT_SYMBOL(genl_register_family_with_ops);
457
458 /**
459  * genl_unregister_family - unregister generic netlink family
460  * @family: generic netlink family
461  *
462  * Unregisters the specified family.
463  *
464  * Returns 0 on success or a negative error code.
465  */
466 int genl_unregister_family(struct genl_family *family)
467 {
468         struct genl_family *rc;
469
470         genl_lock();
471
472         genl_unregister_mc_groups(family);
473
474         list_for_each_entry(rc, genl_family_chain(family->id), family_list) {
475                 if (family->id != rc->id || strcmp(rc->name, family->name))
476                         continue;
477
478                 list_del(&rc->family_list);
479                 INIT_LIST_HEAD(&family->ops_list);
480                 genl_unlock();
481
482                 kfree(family->attrbuf);
483                 genl_ctrl_event(CTRL_CMD_DELFAMILY, family);
484                 return 0;
485         }
486
487         genl_unlock();
488
489         return -ENOENT;
490 }
491 EXPORT_SYMBOL(genl_unregister_family);
492
493 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
494 {
495         struct genl_ops *ops;
496         struct genl_family *family;
497         struct net *net = sock_net(skb->sk);
498         struct genl_info info;
499         struct genlmsghdr *hdr = nlmsg_data(nlh);
500         int hdrlen, err;
501
502         family = genl_family_find_byid(nlh->nlmsg_type);
503         if (family == NULL)
504                 return -ENOENT;
505
506         /* this family doesn't exist in this netns */
507         if (!family->netnsok && !net_eq(net, &init_net))
508                 return -ENOENT;
509
510         hdrlen = GENL_HDRLEN + family->hdrsize;
511         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
512                 return -EINVAL;
513
514         ops = genl_get_cmd(hdr->cmd, family);
515         if (ops == NULL)
516                 return -EOPNOTSUPP;
517
518         if ((ops->flags & GENL_ADMIN_PERM) &&
519             security_netlink_recv(skb, CAP_NET_ADMIN))
520                 return -EPERM;
521
522         if (nlh->nlmsg_flags & NLM_F_DUMP) {
523                 if (ops->dumpit == NULL)
524                         return -EOPNOTSUPP;
525
526                 genl_unlock();
527                 err = netlink_dump_start(net->genl_sock, skb, nlh,
528                                          ops->dumpit, ops->done, 0);
529                 genl_lock();
530                 return err;
531         }
532
533         if (ops->doit == NULL)
534                 return -EOPNOTSUPP;
535
536         if (family->attrbuf) {
537                 err = nlmsg_parse(nlh, hdrlen, family->attrbuf, family->maxattr,
538                                   ops->policy);
539                 if (err < 0)
540                         return err;
541         }
542
543         info.snd_seq = nlh->nlmsg_seq;
544         info.snd_pid = NETLINK_CB(skb).pid;
545         info.nlhdr = nlh;
546         info.genlhdr = nlmsg_data(nlh);
547         info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
548         info.attrs = family->attrbuf;
549         genl_info_net_set(&info, net);
550         memset(&info.user_ptr, 0, sizeof(info.user_ptr));
551
552         if (family->pre_doit) {
553                 err = family->pre_doit(ops, skb, &info);
554                 if (err)
555                         return err;
556         }
557
558         err = ops->doit(skb, &info);
559
560         if (family->post_doit)
561                 family->post_doit(ops, skb, &info);
562
563         return err;
564 }
565
566 static void genl_rcv(struct sk_buff *skb)
567 {
568         genl_lock();
569         netlink_rcv_skb(skb, &genl_rcv_msg);
570         genl_unlock();
571 }
572
573 /**************************************************************************
574  * Controller
575  **************************************************************************/
576
577 static struct genl_family genl_ctrl = {
578         .id = GENL_ID_CTRL,
579         .name = "nlctrl",
580         .version = 0x2,
581         .maxattr = CTRL_ATTR_MAX,
582         .netnsok = true,
583 };
584
585 static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
586                           u32 flags, struct sk_buff *skb, u8 cmd)
587 {
588         void *hdr;
589
590         hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
591         if (hdr == NULL)
592                 return -1;
593
594         NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, family->name);
595         NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, family->id);
596         NLA_PUT_U32(skb, CTRL_ATTR_VERSION, family->version);
597         NLA_PUT_U32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize);
598         NLA_PUT_U32(skb, CTRL_ATTR_MAXATTR, family->maxattr);
599
600         if (!list_empty(&family->ops_list)) {
601                 struct nlattr *nla_ops;
602                 struct genl_ops *ops;
603                 int idx = 1;
604
605                 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
606                 if (nla_ops == NULL)
607                         goto nla_put_failure;
608
609                 list_for_each_entry(ops, &family->ops_list, ops_list) {
610                         struct nlattr *nest;
611
612                         nest = nla_nest_start(skb, idx++);
613                         if (nest == NULL)
614                                 goto nla_put_failure;
615
616                         NLA_PUT_U32(skb, CTRL_ATTR_OP_ID, ops->cmd);
617                         NLA_PUT_U32(skb, CTRL_ATTR_OP_FLAGS, ops->flags);
618
619                         nla_nest_end(skb, nest);
620                 }
621
622                 nla_nest_end(skb, nla_ops);
623         }
624
625         if (!list_empty(&family->mcast_groups)) {
626                 struct genl_multicast_group *grp;
627                 struct nlattr *nla_grps;
628                 int idx = 1;
629
630                 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
631                 if (nla_grps == NULL)
632                         goto nla_put_failure;
633
634                 list_for_each_entry(grp, &family->mcast_groups, list) {
635                         struct nlattr *nest;
636
637                         nest = nla_nest_start(skb, idx++);
638                         if (nest == NULL)
639                                 goto nla_put_failure;
640
641                         NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
642                         NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
643                                        grp->name);
644
645                         nla_nest_end(skb, nest);
646                 }
647                 nla_nest_end(skb, nla_grps);
648         }
649
650         return genlmsg_end(skb, hdr);
651
652 nla_put_failure:
653         genlmsg_cancel(skb, hdr);
654         return -EMSGSIZE;
655 }
656
657 static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 pid,
658                                 u32 seq, u32 flags, struct sk_buff *skb,
659                                 u8 cmd)
660 {
661         void *hdr;
662         struct nlattr *nla_grps;
663         struct nlattr *nest;
664
665         hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
666         if (hdr == NULL)
667                 return -1;
668
669         NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, grp->family->name);
670         NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, grp->family->id);
671
672         nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
673         if (nla_grps == NULL)
674                 goto nla_put_failure;
675
676         nest = nla_nest_start(skb, 1);
677         if (nest == NULL)
678                 goto nla_put_failure;
679
680         NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
681         NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
682                        grp->name);
683
684         nla_nest_end(skb, nest);
685         nla_nest_end(skb, nla_grps);
686
687         return genlmsg_end(skb, hdr);
688
689 nla_put_failure:
690         genlmsg_cancel(skb, hdr);
691         return -EMSGSIZE;
692 }
693
694 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
695 {
696
697         int i, n = 0;
698         struct genl_family *rt;
699         struct net *net = sock_net(skb->sk);
700         int chains_to_skip = cb->args[0];
701         int fams_to_skip = cb->args[1];
702
703         for (i = chains_to_skip; i < GENL_FAM_TAB_SIZE; i++) {
704                 n = 0;
705                 list_for_each_entry(rt, genl_family_chain(i), family_list) {
706                         if (!rt->netnsok && !net_eq(net, &init_net))
707                                 continue;
708                         if (++n < fams_to_skip)
709                                 continue;
710                         if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).pid,
711                                            cb->nlh->nlmsg_seq, NLM_F_MULTI,
712                                            skb, CTRL_CMD_NEWFAMILY) < 0)
713                                 goto errout;
714                 }
715
716                 fams_to_skip = 0;
717         }
718
719 errout:
720         cb->args[0] = i;
721         cb->args[1] = n;
722
723         return skb->len;
724 }
725
726 static struct sk_buff *ctrl_build_family_msg(struct genl_family *family,
727                                              u32 pid, int seq, u8 cmd)
728 {
729         struct sk_buff *skb;
730         int err;
731
732         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
733         if (skb == NULL)
734                 return ERR_PTR(-ENOBUFS);
735
736         err = ctrl_fill_info(family, pid, seq, 0, skb, cmd);
737         if (err < 0) {
738                 nlmsg_free(skb);
739                 return ERR_PTR(err);
740         }
741
742         return skb;
743 }
744
745 static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_multicast_group *grp,
746                                             u32 pid, int seq, u8 cmd)
747 {
748         struct sk_buff *skb;
749         int err;
750
751         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
752         if (skb == NULL)
753                 return ERR_PTR(-ENOBUFS);
754
755         err = ctrl_fill_mcgrp_info(grp, pid, seq, 0, skb, cmd);
756         if (err < 0) {
757                 nlmsg_free(skb);
758                 return ERR_PTR(err);
759         }
760
761         return skb;
762 }
763
764 static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
765         [CTRL_ATTR_FAMILY_ID]   = { .type = NLA_U16 },
766         [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
767                                     .len = GENL_NAMSIZ - 1 },
768 };
769
770 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
771 {
772         struct sk_buff *msg;
773         struct genl_family *res = NULL;
774         int err = -EINVAL;
775
776         if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
777                 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
778                 res = genl_family_find_byid(id);
779                 err = -ENOENT;
780         }
781
782         if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
783                 char *name;
784
785                 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
786                 res = genl_family_find_byname(name);
787                 err = -ENOENT;
788         }
789
790         if (res == NULL)
791                 return err;
792
793         if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) {
794                 /* family doesn't exist here */
795                 return -ENOENT;
796         }
797
798         msg = ctrl_build_family_msg(res, info->snd_pid, info->snd_seq,
799                                     CTRL_CMD_NEWFAMILY);
800         if (IS_ERR(msg))
801                 return PTR_ERR(msg);
802
803         return genlmsg_reply(msg, info);
804 }
805
806 static int genl_ctrl_event(int event, void *data)
807 {
808         struct sk_buff *msg;
809         struct genl_family *family;
810         struct genl_multicast_group *grp;
811
812         /* genl is still initialising */
813         if (!init_net.genl_sock)
814                 return 0;
815
816         switch (event) {
817         case CTRL_CMD_NEWFAMILY:
818         case CTRL_CMD_DELFAMILY:
819                 family = data;
820                 msg = ctrl_build_family_msg(family, 0, 0, event);
821                 break;
822         case CTRL_CMD_NEWMCAST_GRP:
823         case CTRL_CMD_DELMCAST_GRP:
824                 grp = data;
825                 family = grp->family;
826                 msg = ctrl_build_mcgrp_msg(data, 0, 0, event);
827                 break;
828         default:
829                 return -EINVAL;
830         }
831
832         if (IS_ERR(msg))
833                 return PTR_ERR(msg);
834
835         if (!family->netnsok) {
836                 genlmsg_multicast_netns(&init_net, msg, 0,
837                                         GENL_ID_CTRL, GFP_KERNEL);
838         } else {
839                 rcu_read_lock();
840                 genlmsg_multicast_allns(msg, 0, GENL_ID_CTRL, GFP_ATOMIC);
841                 rcu_read_unlock();
842         }
843
844         return 0;
845 }
846
847 static struct genl_ops genl_ctrl_ops = {
848         .cmd            = CTRL_CMD_GETFAMILY,
849         .doit           = ctrl_getfamily,
850         .dumpit         = ctrl_dumpfamily,
851         .policy         = ctrl_policy,
852 };
853
854 static struct genl_multicast_group notify_grp = {
855         .name           = "notify",
856 };
857
858 static int __net_init genl_pernet_init(struct net *net)
859 {
860         /* we'll bump the group number right afterwards */
861         net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, 0,
862                                                genl_rcv, &genl_mutex,
863                                                THIS_MODULE);
864
865         if (!net->genl_sock && net_eq(net, &init_net))
866                 panic("GENL: Cannot initialize generic netlink\n");
867
868         if (!net->genl_sock)
869                 return -ENOMEM;
870
871         return 0;
872 }
873
874 static void __net_exit genl_pernet_exit(struct net *net)
875 {
876         netlink_kernel_release(net->genl_sock);
877         net->genl_sock = NULL;
878 }
879
880 static struct pernet_operations genl_pernet_ops = {
881         .init = genl_pernet_init,
882         .exit = genl_pernet_exit,
883 };
884
885 static int __init genl_init(void)
886 {
887         int i, err;
888
889         for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
890                 INIT_LIST_HEAD(&family_ht[i]);
891
892         err = genl_register_family_with_ops(&genl_ctrl, &genl_ctrl_ops, 1);
893         if (err < 0)
894                 goto problem;
895
896         netlink_set_nonroot(NETLINK_GENERIC, NL_NONROOT_RECV);
897
898         err = register_pernet_subsys(&genl_pernet_ops);
899         if (err)
900                 goto problem;
901
902         err = genl_register_mc_group(&genl_ctrl, &notify_grp);
903         if (err < 0)
904                 goto problem;
905
906         return 0;
907
908 problem:
909         panic("GENL: Cannot register controller: %d\n", err);
910 }
911
912 subsys_initcall(genl_init);
913
914 static int genlmsg_mcast(struct sk_buff *skb, u32 pid, unsigned long group,
915                          gfp_t flags)
916 {
917         struct sk_buff *tmp;
918         struct net *net, *prev = NULL;
919         int err;
920
921         for_each_net_rcu(net) {
922                 if (prev) {
923                         tmp = skb_clone(skb, flags);
924                         if (!tmp) {
925                                 err = -ENOMEM;
926                                 goto error;
927                         }
928                         err = nlmsg_multicast(prev->genl_sock, tmp,
929                                               pid, group, flags);
930                         if (err)
931                                 goto error;
932                 }
933
934                 prev = net;
935         }
936
937         return nlmsg_multicast(prev->genl_sock, skb, pid, group, flags);
938  error:
939         kfree_skb(skb);
940         return err;
941 }
942
943 int genlmsg_multicast_allns(struct sk_buff *skb, u32 pid, unsigned int group,
944                             gfp_t flags)
945 {
946         return genlmsg_mcast(skb, pid, group, flags);
947 }
948 EXPORT_SYMBOL(genlmsg_multicast_allns);