a4b6e148c5dec4ceba8a4aa5ef964353433e2d6a
[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/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>
18 #include <net/sock.h>
19 #include <net/genetlink.h>
20
21 static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */
22
23 static inline void genl_lock(void)
24 {
25         mutex_lock(&genl_mutex);
26 }
27
28 static inline void genl_unlock(void)
29 {
30         mutex_unlock(&genl_mutex);
31 }
32
33 #define GENL_FAM_TAB_SIZE       16
34 #define GENL_FAM_TAB_MASK       (GENL_FAM_TAB_SIZE - 1)
35
36 static struct list_head family_ht[GENL_FAM_TAB_SIZE];
37 /*
38  * Bitmap of multicast groups that are currently in use.
39  *
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.
43  */
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;
47
48 static int genl_ctrl_event(int event, void *data);
49
50 static inline unsigned int genl_family_hash(unsigned int id)
51 {
52         return id & GENL_FAM_TAB_MASK;
53 }
54
55 static inline struct list_head *genl_family_chain(unsigned int id)
56 {
57         return &family_ht[genl_family_hash(id)];
58 }
59
60 static struct genl_family *genl_family_find_byid(unsigned int id)
61 {
62         struct genl_family *f;
63
64         list_for_each_entry(f, genl_family_chain(id), family_list)
65                 if (f->id == id)
66                         return f;
67
68         return NULL;
69 }
70
71 static struct genl_family *genl_family_find_byname(char *name)
72 {
73         struct genl_family *f;
74         int i;
75
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)
79                                 return f;
80
81         return NULL;
82 }
83
84 static struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family)
85 {
86         struct genl_ops *ops;
87
88         list_for_each_entry(ops, &family->ops_list, ops_list)
89                 if (ops->cmd == cmd)
90                         return ops;
91
92         return NULL;
93 }
94
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
97 */
98 static inline u16 genl_generate_id(void)
99 {
100         static u16 id_gen_idx = GENL_MIN_ID;
101         int i;
102
103         for (i = 0; i <= GENL_MAX_ID - GENL_MIN_ID; i++) {
104                 if (!genl_family_find_byid(id_gen_idx))
105                         return id_gen_idx;
106                 if (++id_gen_idx > GENL_MAX_ID)
107                         id_gen_idx = GENL_MIN_ID;
108         }
109
110         return 0;
111 }
112
113 static struct genl_multicast_group notify_grp;
114
115 /**
116  * genl_register_mc_group - register a multicast group
117  *
118  * Registers the specified multicast group and notifies userspace
119  * about the new group.
120  *
121  * Returns 0 on success or a negative error code.
122  *
123  * @family: The generic netlink family the group shall be registered for.
124  * @grp: The group to register, must have a name.
125  */
126 int genl_register_mc_group(struct genl_family *family,
127                            struct genl_multicast_group *grp)
128 {
129         int id;
130         unsigned long *new_groups;
131         int err = 0;
132
133         BUG_ON(grp->name[0] == '\0');
134
135         genl_lock();
136
137         /* special-case our own group */
138         if (grp == &notify_grp)
139                 id = GENL_ID_CTRL;
140         else
141                 id = find_first_zero_bit(mc_groups,
142                                          mc_groups_longs * BITS_PER_LONG);
143
144
145         if (id >= mc_groups_longs * BITS_PER_LONG) {
146                 size_t nlen = (mc_groups_longs + 1) * sizeof(unsigned long);
147
148                 if (mc_groups == &mc_group_start) {
149                         new_groups = kzalloc(nlen, GFP_KERNEL);
150                         if (!new_groups) {
151                                 err = -ENOMEM;
152                                 goto out;
153                         }
154                         mc_groups = new_groups;
155                         *mc_groups = mc_group_start;
156                 } else {
157                         new_groups = krealloc(mc_groups, nlen, GFP_KERNEL);
158                         if (!new_groups) {
159                                 err = -ENOMEM;
160                                 goto out;
161                         }
162                         mc_groups = new_groups;
163                         mc_groups[mc_groups_longs] = 0;
164                 }
165                 mc_groups_longs++;
166         }
167
168         if (family->netnsok) {
169                 struct net *net;
170
171                 netlink_table_grab();
172                 rcu_read_lock();
173                 for_each_net_rcu(net) {
174                         err = __netlink_change_ngroups(net->genl_sock,
175                                         mc_groups_longs * BITS_PER_LONG);
176                         if (err) {
177                                 /*
178                                  * No need to roll back, can only fail if
179                                  * memory allocation fails and then the
180                                  * number of _possible_ groups has been
181                                  * increased on some sockets which is ok.
182                                  */
183                                 rcu_read_unlock();
184                                 netlink_table_ungrab();
185                                 goto out;
186                         }
187                 }
188                 rcu_read_unlock();
189                 netlink_table_ungrab();
190         } else {
191                 err = netlink_change_ngroups(init_net.genl_sock,
192                                              mc_groups_longs * BITS_PER_LONG);
193                 if (err)
194                         goto out;
195         }
196
197         grp->id = id;
198         set_bit(id, mc_groups);
199         list_add_tail(&grp->list, &family->mcast_groups);
200         grp->family = family;
201
202         genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, grp);
203  out:
204         genl_unlock();
205         return err;
206 }
207 EXPORT_SYMBOL(genl_register_mc_group);
208
209 static void __genl_unregister_mc_group(struct genl_family *family,
210                                        struct genl_multicast_group *grp)
211 {
212         struct net *net;
213         BUG_ON(grp->family != family);
214
215         netlink_table_grab();
216         rcu_read_lock();
217         for_each_net_rcu(net)
218                 __netlink_clear_multicast_users(net->genl_sock, grp->id);
219         rcu_read_unlock();
220         netlink_table_ungrab();
221
222         clear_bit(grp->id, mc_groups);
223         list_del(&grp->list);
224         genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, grp);
225         grp->id = 0;
226         grp->family = NULL;
227 }
228
229 /**
230  * genl_unregister_mc_group - unregister a multicast group
231  *
232  * Unregisters the specified multicast group and notifies userspace
233  * about it. All current listeners on the group are removed.
234  *
235  * Note: It is not necessary to unregister all multicast groups before
236  *       unregistering the family, unregistering the family will cause
237  *       all assigned multicast groups to be unregistered automatically.
238  *
239  * @family: Generic netlink family the group belongs to.
240  * @grp: The group to unregister, must have been registered successfully
241  *       previously.
242  */
243 void genl_unregister_mc_group(struct genl_family *family,
244                               struct genl_multicast_group *grp)
245 {
246         genl_lock();
247         __genl_unregister_mc_group(family, grp);
248         genl_unlock();
249 }
250 EXPORT_SYMBOL(genl_unregister_mc_group);
251
252 static void genl_unregister_mc_groups(struct genl_family *family)
253 {
254         struct genl_multicast_group *grp, *tmp;
255
256         list_for_each_entry_safe(grp, tmp, &family->mcast_groups, list)
257                 __genl_unregister_mc_group(family, grp);
258 }
259
260 /**
261  * genl_register_ops - register generic netlink operations
262  * @family: generic netlink family
263  * @ops: operations to be registered
264  *
265  * Registers the specified operations and assigns them to the specified
266  * family. Either a doit or dumpit callback must be specified or the
267  * operation will fail. Only one operation structure per command
268  * identifier may be registered.
269  *
270  * See include/net/genetlink.h for more documenation on the operations
271  * structure.
272  *
273  * Returns 0 on success or a negative error code.
274  */
275 int genl_register_ops(struct genl_family *family, struct genl_ops *ops)
276 {
277         int err = -EINVAL;
278
279         if (ops->dumpit == NULL && ops->doit == NULL)
280                 goto errout;
281
282         if (genl_get_cmd(ops->cmd, family)) {
283                 err = -EEXIST;
284                 goto errout;
285         }
286
287         if (ops->dumpit)
288                 ops->flags |= GENL_CMD_CAP_DUMP;
289         if (ops->doit)
290                 ops->flags |= GENL_CMD_CAP_DO;
291         if (ops->policy)
292                 ops->flags |= GENL_CMD_CAP_HASPOL;
293
294         genl_lock();
295         list_add_tail(&ops->ops_list, &family->ops_list);
296         genl_unlock();
297
298         genl_ctrl_event(CTRL_CMD_NEWOPS, ops);
299         err = 0;
300 errout:
301         return err;
302 }
303
304 /**
305  * genl_unregister_ops - unregister generic netlink operations
306  * @family: generic netlink family
307  * @ops: operations to be unregistered
308  *
309  * Unregisters the specified operations and unassigns them from the
310  * specified family. The operation blocks until the current message
311  * processing has finished and doesn't start again until the
312  * unregister process has finished.
313  *
314  * Note: It is not necessary to unregister all operations before
315  *       unregistering the family, unregistering the family will cause
316  *       all assigned operations to be unregistered automatically.
317  *
318  * Returns 0 on success or a negative error code.
319  */
320 int genl_unregister_ops(struct genl_family *family, struct genl_ops *ops)
321 {
322         struct genl_ops *rc;
323
324         genl_lock();
325         list_for_each_entry(rc, &family->ops_list, ops_list) {
326                 if (rc == ops) {
327                         list_del(&ops->ops_list);
328                         genl_unlock();
329                         genl_ctrl_event(CTRL_CMD_DELOPS, ops);
330                         return 0;
331                 }
332         }
333         genl_unlock();
334
335         return -ENOENT;
336 }
337
338 /**
339  * genl_register_family - register a generic netlink family
340  * @family: generic netlink family
341  *
342  * Registers the specified family after validating it first. Only one
343  * family may be registered with the same family name or identifier.
344  * The family id may equal GENL_ID_GENERATE causing an unique id to
345  * be automatically generated and assigned.
346  *
347  * Return 0 on success or a negative error code.
348  */
349 int genl_register_family(struct genl_family *family)
350 {
351         int err = -EINVAL;
352
353         if (family->id && family->id < GENL_MIN_ID)
354                 goto errout;
355
356         if (family->id > GENL_MAX_ID)
357                 goto errout;
358
359         INIT_LIST_HEAD(&family->ops_list);
360         INIT_LIST_HEAD(&family->mcast_groups);
361
362         genl_lock();
363
364         if (genl_family_find_byname(family->name)) {
365                 err = -EEXIST;
366                 goto errout_locked;
367         }
368
369         if (family->id == GENL_ID_GENERATE) {
370                 u16 newid = genl_generate_id();
371
372                 if (!newid) {
373                         err = -ENOMEM;
374                         goto errout_locked;
375                 }
376
377                 family->id = newid;
378         } else if (genl_family_find_byid(family->id)) {
379                 err = -EEXIST;
380                 goto errout_locked;
381         }
382
383         if (family->maxattr) {
384                 family->attrbuf = kmalloc((family->maxattr+1) *
385                                         sizeof(struct nlattr *), GFP_KERNEL);
386                 if (family->attrbuf == NULL) {
387                         err = -ENOMEM;
388                         goto errout_locked;
389                 }
390         } else
391                 family->attrbuf = NULL;
392
393         list_add_tail(&family->family_list, genl_family_chain(family->id));
394         genl_unlock();
395
396         genl_ctrl_event(CTRL_CMD_NEWFAMILY, family);
397
398         return 0;
399
400 errout_locked:
401         genl_unlock();
402 errout:
403         return err;
404 }
405
406 /**
407  * genl_register_family_with_ops - register a generic netlink family
408  * @family: generic netlink family
409  * @ops: operations to be registered
410  * @n_ops: number of elements to register
411  *
412  * Registers the specified family and operations from the specified table.
413  * Only one family may be registered with the same family name or identifier.
414  *
415  * The family id may equal GENL_ID_GENERATE causing an unique id to
416  * be automatically generated and assigned.
417  *
418  * Either a doit or dumpit callback must be specified for every registered
419  * operation or the function will fail. Only one operation structure per
420  * command identifier may be registered.
421  *
422  * See include/net/genetlink.h for more documenation on the operations
423  * structure.
424  *
425  * This is equivalent to calling genl_register_family() followed by
426  * genl_register_ops() for every operation entry in the table taking
427  * care to unregister the family on error path.
428  *
429  * Return 0 on success or a negative error code.
430  */
431 int genl_register_family_with_ops(struct genl_family *family,
432         struct genl_ops *ops, size_t n_ops)
433 {
434         int err, i;
435
436         err = genl_register_family(family);
437         if (err)
438                 return err;
439
440         for (i = 0; i < n_ops; ++i, ++ops) {
441                 err = genl_register_ops(family, ops);
442                 if (err)
443                         goto err_out;
444         }
445         return 0;
446 err_out:
447         genl_unregister_family(family);
448         return err;
449 }
450 EXPORT_SYMBOL(genl_register_family_with_ops);
451
452 /**
453  * genl_unregister_family - unregister generic netlink family
454  * @family: generic netlink family
455  *
456  * Unregisters the specified family.
457  *
458  * Returns 0 on success or a negative error code.
459  */
460 int genl_unregister_family(struct genl_family *family)
461 {
462         struct genl_family *rc;
463
464         genl_lock();
465
466         genl_unregister_mc_groups(family);
467
468         list_for_each_entry(rc, genl_family_chain(family->id), family_list) {
469                 if (family->id != rc->id || strcmp(rc->name, family->name))
470                         continue;
471
472                 list_del(&rc->family_list);
473                 INIT_LIST_HEAD(&family->ops_list);
474                 genl_unlock();
475
476                 kfree(family->attrbuf);
477                 genl_ctrl_event(CTRL_CMD_DELFAMILY, family);
478                 return 0;
479         }
480
481         genl_unlock();
482
483         return -ENOENT;
484 }
485
486 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
487 {
488         struct genl_ops *ops;
489         struct genl_family *family;
490         struct net *net = sock_net(skb->sk);
491         struct genl_info info;
492         struct genlmsghdr *hdr = nlmsg_data(nlh);
493         int hdrlen, err;
494
495         family = genl_family_find_byid(nlh->nlmsg_type);
496         if (family == NULL)
497                 return -ENOENT;
498
499         /* this family doesn't exist in this netns */
500         if (!family->netnsok && !net_eq(net, &init_net))
501                 return -ENOENT;
502
503         hdrlen = GENL_HDRLEN + family->hdrsize;
504         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
505                 return -EINVAL;
506
507         ops = genl_get_cmd(hdr->cmd, family);
508         if (ops == NULL)
509                 return -EOPNOTSUPP;
510
511         if ((ops->flags & GENL_ADMIN_PERM) &&
512             security_netlink_recv(skb, CAP_NET_ADMIN))
513                 return -EPERM;
514
515         if (nlh->nlmsg_flags & NLM_F_DUMP) {
516                 if (ops->dumpit == NULL)
517                         return -EOPNOTSUPP;
518
519                 genl_unlock();
520                 err = netlink_dump_start(net->genl_sock, skb, nlh,
521                                          ops->dumpit, ops->done);
522                 genl_lock();
523                 return err;
524         }
525
526         if (ops->doit == NULL)
527                 return -EOPNOTSUPP;
528
529         if (family->attrbuf) {
530                 err = nlmsg_parse(nlh, hdrlen, family->attrbuf, family->maxattr,
531                                   ops->policy);
532                 if (err < 0)
533                         return err;
534         }
535
536         info.snd_seq = nlh->nlmsg_seq;
537         info.snd_pid = NETLINK_CB(skb).pid;
538         info.nlhdr = nlh;
539         info.genlhdr = nlmsg_data(nlh);
540         info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
541         info.attrs = family->attrbuf;
542         genl_info_net_set(&info, net);
543
544         return ops->doit(skb, &info);
545 }
546
547 static void genl_rcv(struct sk_buff *skb)
548 {
549         genl_lock();
550         netlink_rcv_skb(skb, &genl_rcv_msg);
551         genl_unlock();
552 }
553
554 /**************************************************************************
555  * Controller
556  **************************************************************************/
557
558 static struct genl_family genl_ctrl = {
559         .id = GENL_ID_CTRL,
560         .name = "nlctrl",
561         .version = 0x2,
562         .maxattr = CTRL_ATTR_MAX,
563         .netnsok = true,
564 };
565
566 static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
567                           u32 flags, struct sk_buff *skb, u8 cmd)
568 {
569         void *hdr;
570
571         hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
572         if (hdr == NULL)
573                 return -1;
574
575         NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, family->name);
576         NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, family->id);
577         NLA_PUT_U32(skb, CTRL_ATTR_VERSION, family->version);
578         NLA_PUT_U32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize);
579         NLA_PUT_U32(skb, CTRL_ATTR_MAXATTR, family->maxattr);
580
581         if (!list_empty(&family->ops_list)) {
582                 struct nlattr *nla_ops;
583                 struct genl_ops *ops;
584                 int idx = 1;
585
586                 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
587                 if (nla_ops == NULL)
588                         goto nla_put_failure;
589
590                 list_for_each_entry(ops, &family->ops_list, ops_list) {
591                         struct nlattr *nest;
592
593                         nest = nla_nest_start(skb, idx++);
594                         if (nest == NULL)
595                                 goto nla_put_failure;
596
597                         NLA_PUT_U32(skb, CTRL_ATTR_OP_ID, ops->cmd);
598                         NLA_PUT_U32(skb, CTRL_ATTR_OP_FLAGS, ops->flags);
599
600                         nla_nest_end(skb, nest);
601                 }
602
603                 nla_nest_end(skb, nla_ops);
604         }
605
606         if (!list_empty(&family->mcast_groups)) {
607                 struct genl_multicast_group *grp;
608                 struct nlattr *nla_grps;
609                 int idx = 1;
610
611                 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
612                 if (nla_grps == NULL)
613                         goto nla_put_failure;
614
615                 list_for_each_entry(grp, &family->mcast_groups, list) {
616                         struct nlattr *nest;
617
618                         nest = nla_nest_start(skb, idx++);
619                         if (nest == NULL)
620                                 goto nla_put_failure;
621
622                         NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
623                         NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
624                                        grp->name);
625
626                         nla_nest_end(skb, nest);
627                 }
628                 nla_nest_end(skb, nla_grps);
629         }
630
631         return genlmsg_end(skb, hdr);
632
633 nla_put_failure:
634         genlmsg_cancel(skb, hdr);
635         return -EMSGSIZE;
636 }
637
638 static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 pid,
639                                 u32 seq, u32 flags, struct sk_buff *skb,
640                                 u8 cmd)
641 {
642         void *hdr;
643         struct nlattr *nla_grps;
644         struct nlattr *nest;
645
646         hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
647         if (hdr == NULL)
648                 return -1;
649
650         NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, grp->family->name);
651         NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, grp->family->id);
652
653         nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
654         if (nla_grps == NULL)
655                 goto nla_put_failure;
656
657         nest = nla_nest_start(skb, 1);
658         if (nest == NULL)
659                 goto nla_put_failure;
660
661         NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
662         NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
663                        grp->name);
664
665         nla_nest_end(skb, nest);
666         nla_nest_end(skb, nla_grps);
667
668         return genlmsg_end(skb, hdr);
669
670 nla_put_failure:
671         genlmsg_cancel(skb, hdr);
672         return -EMSGSIZE;
673 }
674
675 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
676 {
677
678         int i, n = 0;
679         struct genl_family *rt;
680         struct net *net = sock_net(skb->sk);
681         int chains_to_skip = cb->args[0];
682         int fams_to_skip = cb->args[1];
683
684         for (i = chains_to_skip; i < GENL_FAM_TAB_SIZE; i++) {
685                 n = 0;
686                 list_for_each_entry(rt, genl_family_chain(i), family_list) {
687                         if (!rt->netnsok && !net_eq(net, &init_net))
688                                 continue;
689                         if (++n < fams_to_skip)
690                                 continue;
691                         if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).pid,
692                                            cb->nlh->nlmsg_seq, NLM_F_MULTI,
693                                            skb, CTRL_CMD_NEWFAMILY) < 0)
694                                 goto errout;
695                 }
696
697                 fams_to_skip = 0;
698         }
699
700 errout:
701         cb->args[0] = i;
702         cb->args[1] = n;
703
704         return skb->len;
705 }
706
707 static struct sk_buff *ctrl_build_family_msg(struct genl_family *family,
708                                              u32 pid, int seq, u8 cmd)
709 {
710         struct sk_buff *skb;
711         int err;
712
713         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
714         if (skb == NULL)
715                 return ERR_PTR(-ENOBUFS);
716
717         err = ctrl_fill_info(family, pid, seq, 0, skb, cmd);
718         if (err < 0) {
719                 nlmsg_free(skb);
720                 return ERR_PTR(err);
721         }
722
723         return skb;
724 }
725
726 static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_multicast_group *grp,
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_mcgrp_info(grp, 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 const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
746         [CTRL_ATTR_FAMILY_ID]   = { .type = NLA_U16 },
747         [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
748                                     .len = GENL_NAMSIZ - 1 },
749 };
750
751 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
752 {
753         struct sk_buff *msg;
754         struct genl_family *res = NULL;
755         int err = -EINVAL;
756
757         if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
758                 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
759                 res = genl_family_find_byid(id);
760                 err = -ENOENT;
761         }
762
763         if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
764                 char *name;
765
766                 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
767                 res = genl_family_find_byname(name);
768                 err = -ENOENT;
769         }
770
771         if (res == NULL)
772                 return err;
773
774         if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) {
775                 /* family doesn't exist here */
776                 return -ENOENT;
777         }
778
779         msg = ctrl_build_family_msg(res, info->snd_pid, info->snd_seq,
780                                     CTRL_CMD_NEWFAMILY);
781         if (IS_ERR(msg))
782                 return PTR_ERR(msg);
783
784         return genlmsg_reply(msg, info);
785 }
786
787 static int genl_ctrl_event(int event, void *data)
788 {
789         struct sk_buff *msg;
790         struct genl_family *family;
791         struct genl_multicast_group *grp;
792
793         /* genl is still initialising */
794         if (!init_net.genl_sock)
795                 return 0;
796
797         switch (event) {
798         case CTRL_CMD_NEWFAMILY:
799         case CTRL_CMD_DELFAMILY:
800                 family = data;
801                 msg = ctrl_build_family_msg(family, 0, 0, event);
802                 break;
803         case CTRL_CMD_NEWMCAST_GRP:
804         case CTRL_CMD_DELMCAST_GRP:
805                 grp = data;
806                 family = grp->family;
807                 msg = ctrl_build_mcgrp_msg(data, 0, 0, event);
808                 break;
809         default:
810                 return -EINVAL;
811         }
812
813         if (IS_ERR(msg))
814                 return PTR_ERR(msg);
815
816         if (!family->netnsok) {
817                 genlmsg_multicast_netns(&init_net, msg, 0,
818                                         GENL_ID_CTRL, GFP_KERNEL);
819         } else {
820                 rcu_read_lock();
821                 genlmsg_multicast_allns(msg, 0, GENL_ID_CTRL, GFP_ATOMIC);
822                 rcu_read_unlock();
823         }
824
825         return 0;
826 }
827
828 static struct genl_ops genl_ctrl_ops = {
829         .cmd            = CTRL_CMD_GETFAMILY,
830         .doit           = ctrl_getfamily,
831         .dumpit         = ctrl_dumpfamily,
832         .policy         = ctrl_policy,
833 };
834
835 static struct genl_multicast_group notify_grp = {
836         .name           = "notify",
837 };
838
839 static int __net_init genl_pernet_init(struct net *net)
840 {
841         /* we'll bump the group number right afterwards */
842         net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, 0,
843                                                genl_rcv, &genl_mutex,
844                                                THIS_MODULE);
845
846         if (!net->genl_sock && net_eq(net, &init_net))
847                 panic("GENL: Cannot initialize generic netlink\n");
848
849         if (!net->genl_sock)
850                 return -ENOMEM;
851
852         return 0;
853 }
854
855 static void __net_exit genl_pernet_exit(struct net *net)
856 {
857         netlink_kernel_release(net->genl_sock);
858         net->genl_sock = NULL;
859 }
860
861 static struct pernet_operations genl_pernet_ops = {
862         .init = genl_pernet_init,
863         .exit = genl_pernet_exit,
864 };
865
866 static int __init genl_init(void)
867 {
868         int i, err;
869
870         for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
871                 INIT_LIST_HEAD(&family_ht[i]);
872
873         err = genl_register_family(&genl_ctrl);
874         if (err < 0)
875                 goto problem;
876
877         err = genl_register_ops(&genl_ctrl, &genl_ctrl_ops);
878         if (err < 0)
879                 goto problem;
880
881         netlink_set_nonroot(NETLINK_GENERIC, NL_NONROOT_RECV);
882
883         err = register_pernet_subsys(&genl_pernet_ops);
884         if (err)
885                 goto problem;
886
887         err = genl_register_mc_group(&genl_ctrl, &notify_grp);
888         if (err < 0)
889                 goto problem;
890
891         return 0;
892
893 problem:
894         panic("GENL: Cannot register controller: %d\n", err);
895 }
896
897 subsys_initcall(genl_init);
898
899 EXPORT_SYMBOL(genl_register_ops);
900 EXPORT_SYMBOL(genl_unregister_ops);
901 EXPORT_SYMBOL(genl_register_family);
902 EXPORT_SYMBOL(genl_unregister_family);
903
904 static int genlmsg_mcast(struct sk_buff *skb, u32 pid, unsigned long group,
905                          gfp_t flags)
906 {
907         struct sk_buff *tmp;
908         struct net *net, *prev = NULL;
909         int err;
910
911         for_each_net_rcu(net) {
912                 if (prev) {
913                         tmp = skb_clone(skb, flags);
914                         if (!tmp) {
915                                 err = -ENOMEM;
916                                 goto error;
917                         }
918                         err = nlmsg_multicast(prev->genl_sock, tmp,
919                                               pid, group, flags);
920                         if (err)
921                                 goto error;
922                 }
923
924                 prev = net;
925         }
926
927         return nlmsg_multicast(prev->genl_sock, skb, pid, group, flags);
928  error:
929         kfree_skb(skb);
930         return err;
931 }
932
933 int genlmsg_multicast_allns(struct sk_buff *skb, u32 pid, unsigned int group,
934                             gfp_t flags)
935 {
936         return genlmsg_mcast(skb, pid, group, flags);
937 }
938 EXPORT_SYMBOL(genlmsg_multicast_allns);