150579a21469d664563dfcee8bdef5d3f0e355e1
[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 struct sock *genl_sock = NULL;
22
23 static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */
24
25 static inline void genl_lock(void)
26 {
27         mutex_lock(&genl_mutex);
28 }
29
30 static inline void genl_unlock(void)
31 {
32         mutex_unlock(&genl_mutex);
33 }
34
35 #define GENL_FAM_TAB_SIZE       16
36 #define GENL_FAM_TAB_MASK       (GENL_FAM_TAB_SIZE - 1)
37
38 static struct list_head family_ht[GENL_FAM_TAB_SIZE];
39 /*
40  * Bitmap of multicast groups that are currently in use.
41  *
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.
45  */
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;
49
50 static int genl_ctrl_event(int event, void *data);
51
52 static inline unsigned int genl_family_hash(unsigned int id)
53 {
54         return id & GENL_FAM_TAB_MASK;
55 }
56
57 static inline struct list_head *genl_family_chain(unsigned int id)
58 {
59         return &family_ht[genl_family_hash(id)];
60 }
61
62 static struct genl_family *genl_family_find_byid(unsigned int id)
63 {
64         struct genl_family *f;
65
66         list_for_each_entry(f, genl_family_chain(id), family_list)
67                 if (f->id == id)
68                         return f;
69
70         return NULL;
71 }
72
73 static struct genl_family *genl_family_find_byname(char *name)
74 {
75         struct genl_family *f;
76         int i;
77
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)
81                                 return f;
82
83         return NULL;
84 }
85
86 static struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family)
87 {
88         struct genl_ops *ops;
89
90         list_for_each_entry(ops, &family->ops_list, ops_list)
91                 if (ops->cmd == cmd)
92                         return ops;
93
94         return NULL;
95 }
96
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
99 */
100 static inline u16 genl_generate_id(void)
101 {
102         static u16 id_gen_idx;
103         int overflowed = 0;
104
105         do {
106                 if (id_gen_idx == 0)
107                         id_gen_idx = GENL_MIN_ID;
108
109                 if (++id_gen_idx > GENL_MAX_ID) {
110                         if (!overflowed) {
111                                 overflowed = 1;
112                                 id_gen_idx = 0;
113                                 continue;
114                         } else
115                                 return 0;
116                 }
117
118         } while (genl_family_find_byid(id_gen_idx));
119
120         return id_gen_idx;
121 }
122
123 static struct genl_multicast_group notify_grp;
124
125 /**
126  * genl_register_mc_group - register a multicast group
127  *
128  * Registers the specified multicast group and notifies userspace
129  * about the new group.
130  *
131  * Returns 0 on success or a negative error code.
132  *
133  * @family: The generic netlink family the group shall be registered for.
134  * @grp: The group to register, must have a name.
135  */
136 int genl_register_mc_group(struct genl_family *family,
137                            struct genl_multicast_group *grp)
138 {
139         int id;
140         unsigned long *new_groups;
141         int err;
142
143         BUG_ON(grp->name[0] == '\0');
144
145         genl_lock();
146
147         /* special-case our own group */
148         if (grp == &notify_grp)
149                 id = GENL_ID_CTRL;
150         else
151                 id = find_first_zero_bit(mc_groups,
152                                          mc_groups_longs * BITS_PER_LONG);
153
154
155         if (id >= mc_groups_longs * BITS_PER_LONG) {
156                 size_t nlen = (mc_groups_longs + 1) * sizeof(unsigned long);
157
158                 if (mc_groups == &mc_group_start) {
159                         new_groups = kzalloc(nlen, GFP_KERNEL);
160                         if (!new_groups) {
161                                 err = -ENOMEM;
162                                 goto out;
163                         }
164                         mc_groups = new_groups;
165                         *mc_groups = mc_group_start;
166                 } else {
167                         new_groups = krealloc(mc_groups, nlen, GFP_KERNEL);
168                         if (!new_groups) {
169                                 err = -ENOMEM;
170                                 goto out;
171                         }
172                         mc_groups = new_groups;
173                         mc_groups[mc_groups_longs] = 0;
174                 }
175                 mc_groups_longs++;
176         }
177
178         err = netlink_change_ngroups(genl_sock,
179                                      mc_groups_longs * BITS_PER_LONG);
180         if (err)
181                 goto out;
182
183         grp->id = id;
184         set_bit(id, mc_groups);
185         list_add_tail(&grp->list, &family->mcast_groups);
186         grp->family = family;
187
188         genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, grp);
189  out:
190         genl_unlock();
191         return err;
192 }
193 EXPORT_SYMBOL(genl_register_mc_group);
194
195 static void __genl_unregister_mc_group(struct genl_family *family,
196                                        struct genl_multicast_group *grp)
197 {
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);
203         grp->id = 0;
204         grp->family = NULL;
205 }
206
207 /**
208  * genl_unregister_mc_group - unregister a multicast group
209  *
210  * Unregisters the specified multicast group and notifies userspace
211  * about it. All current listeners on the group are removed.
212  *
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.
216  *
217  * @family: Generic netlink family the group belongs to.
218  * @grp: The group to unregister, must have been registered successfully
219  *       previously.
220  */
221 void genl_unregister_mc_group(struct genl_family *family,
222                               struct genl_multicast_group *grp)
223 {
224         genl_lock();
225         __genl_unregister_mc_group(family, grp);
226         genl_unlock();
227 }
228
229 static void genl_unregister_mc_groups(struct genl_family *family)
230 {
231         struct genl_multicast_group *grp, *tmp;
232
233         genl_lock();
234         list_for_each_entry_safe(grp, tmp, &family->mcast_groups, list)
235                 __genl_unregister_mc_group(family, grp);
236         genl_unlock();
237 }
238
239 /**
240  * genl_register_ops - register generic netlink operations
241  * @family: generic netlink family
242  * @ops: operations to be registered
243  *
244  * Registers the specified operations and assigns them to the specified
245  * family. Either a doit or dumpit callback must be specified or the
246  * operation will fail. Only one operation structure per command
247  * identifier may be registered.
248  *
249  * See include/net/genetlink.h for more documenation on the operations
250  * structure.
251  *
252  * Returns 0 on success or a negative error code.
253  */
254 int genl_register_ops(struct genl_family *family, struct genl_ops *ops)
255 {
256         int err = -EINVAL;
257
258         if (ops->dumpit == NULL && ops->doit == NULL)
259                 goto errout;
260
261         if (genl_get_cmd(ops->cmd, family)) {
262                 err = -EEXIST;
263                 goto errout;
264         }
265
266         if (ops->dumpit)
267                 ops->flags |= GENL_CMD_CAP_DUMP;
268         if (ops->doit)
269                 ops->flags |= GENL_CMD_CAP_DO;
270         if (ops->policy)
271                 ops->flags |= GENL_CMD_CAP_HASPOL;
272
273         genl_lock();
274         list_add_tail(&ops->ops_list, &family->ops_list);
275         genl_unlock();
276
277         genl_ctrl_event(CTRL_CMD_NEWOPS, ops);
278         err = 0;
279 errout:
280         return err;
281 }
282
283 /**
284  * genl_unregister_ops - unregister generic netlink operations
285  * @family: generic netlink family
286  * @ops: operations to be unregistered
287  *
288  * Unregisters the specified operations and unassigns them from the
289  * specified family. The operation blocks until the current message
290  * processing has finished and doesn't start again until the
291  * unregister process has finished.
292  *
293  * Note: It is not necessary to unregister all operations before
294  *       unregistering the family, unregistering the family will cause
295  *       all assigned operations to be unregistered automatically.
296  *
297  * Returns 0 on success or a negative error code.
298  */
299 int genl_unregister_ops(struct genl_family *family, struct genl_ops *ops)
300 {
301         struct genl_ops *rc;
302
303         genl_lock();
304         list_for_each_entry(rc, &family->ops_list, ops_list) {
305                 if (rc == ops) {
306                         list_del(&ops->ops_list);
307                         genl_unlock();
308                         genl_ctrl_event(CTRL_CMD_DELOPS, ops);
309                         return 0;
310                 }
311         }
312         genl_unlock();
313
314         return -ENOENT;
315 }
316
317 /**
318  * genl_register_family - register a generic netlink family
319  * @family: generic netlink family
320  *
321  * Registers the specified family after validating it first. Only one
322  * family may be registered with the same family name or identifier.
323  * The family id may equal GENL_ID_GENERATE causing an unique id to
324  * be automatically generated and assigned.
325  *
326  * Return 0 on success or a negative error code.
327  */
328 int genl_register_family(struct genl_family *family)
329 {
330         int err = -EINVAL;
331
332         if (family->id && family->id < GENL_MIN_ID)
333                 goto errout;
334
335         if (family->id > GENL_MAX_ID)
336                 goto errout;
337
338         INIT_LIST_HEAD(&family->ops_list);
339         INIT_LIST_HEAD(&family->mcast_groups);
340
341         genl_lock();
342
343         if (genl_family_find_byname(family->name)) {
344                 err = -EEXIST;
345                 goto errout_locked;
346         }
347
348         if (genl_family_find_byid(family->id)) {
349                 err = -EEXIST;
350                 goto errout_locked;
351         }
352
353         if (family->id == GENL_ID_GENERATE) {
354                 u16 newid = genl_generate_id();
355
356                 if (!newid) {
357                         err = -ENOMEM;
358                         goto errout_locked;
359                 }
360
361                 family->id = newid;
362         }
363
364         if (family->maxattr) {
365                 family->attrbuf = kmalloc((family->maxattr+1) *
366                                         sizeof(struct nlattr *), GFP_KERNEL);
367                 if (family->attrbuf == NULL) {
368                         err = -ENOMEM;
369                         goto errout_locked;
370                 }
371         } else
372                 family->attrbuf = NULL;
373
374         list_add_tail(&family->family_list, genl_family_chain(family->id));
375         genl_unlock();
376
377         genl_ctrl_event(CTRL_CMD_NEWFAMILY, family);
378
379         return 0;
380
381 errout_locked:
382         genl_unlock();
383 errout:
384         return err;
385 }
386
387 /**
388  * genl_unregister_family - unregister generic netlink family
389  * @family: generic netlink family
390  *
391  * Unregisters the specified family.
392  *
393  * Returns 0 on success or a negative error code.
394  */
395 int genl_unregister_family(struct genl_family *family)
396 {
397         struct genl_family *rc;
398
399         genl_unregister_mc_groups(family);
400
401         genl_lock();
402
403         list_for_each_entry(rc, genl_family_chain(family->id), family_list) {
404                 if (family->id != rc->id || strcmp(rc->name, family->name))
405                         continue;
406
407                 list_del(&rc->family_list);
408                 INIT_LIST_HEAD(&family->ops_list);
409                 genl_unlock();
410
411                 kfree(family->attrbuf);
412                 genl_ctrl_event(CTRL_CMD_DELFAMILY, family);
413                 return 0;
414         }
415
416         genl_unlock();
417
418         return -ENOENT;
419 }
420
421 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
422 {
423         struct genl_ops *ops;
424         struct genl_family *family;
425         struct genl_info info;
426         struct genlmsghdr *hdr = nlmsg_data(nlh);
427         int hdrlen, err;
428
429         family = genl_family_find_byid(nlh->nlmsg_type);
430         if (family == NULL)
431                 return -ENOENT;
432
433         hdrlen = GENL_HDRLEN + family->hdrsize;
434         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
435                 return -EINVAL;
436
437         ops = genl_get_cmd(hdr->cmd, family);
438         if (ops == NULL)
439                 return -EOPNOTSUPP;
440
441         if ((ops->flags & GENL_ADMIN_PERM) &&
442             security_netlink_recv(skb, CAP_NET_ADMIN))
443                 return -EPERM;
444
445         if (nlh->nlmsg_flags & NLM_F_DUMP) {
446                 if (ops->dumpit == NULL)
447                         return -EOPNOTSUPP;
448
449                 return netlink_dump_start(genl_sock, skb, nlh,
450                                           ops->dumpit, ops->done);
451         }
452
453         if (ops->doit == NULL)
454                 return -EOPNOTSUPP;
455
456         if (family->attrbuf) {
457                 err = nlmsg_parse(nlh, hdrlen, family->attrbuf, family->maxattr,
458                                   ops->policy);
459                 if (err < 0)
460                         return err;
461         }
462
463         info.snd_seq = nlh->nlmsg_seq;
464         info.snd_pid = NETLINK_CB(skb).pid;
465         info.nlhdr = nlh;
466         info.genlhdr = nlmsg_data(nlh);
467         info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
468         info.attrs = family->attrbuf;
469
470         return ops->doit(skb, &info);
471 }
472
473 static void genl_rcv(struct sk_buff *skb)
474 {
475         genl_lock();
476         netlink_rcv_skb(skb, &genl_rcv_msg);
477         genl_unlock();
478 }
479
480 /**************************************************************************
481  * Controller
482  **************************************************************************/
483
484 static struct genl_family genl_ctrl = {
485         .id = GENL_ID_CTRL,
486         .name = "nlctrl",
487         .version = 0x2,
488         .maxattr = CTRL_ATTR_MAX,
489 };
490
491 static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
492                           u32 flags, struct sk_buff *skb, u8 cmd)
493 {
494         void *hdr;
495
496         hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
497         if (hdr == NULL)
498                 return -1;
499
500         NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, family->name);
501         NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, family->id);
502         NLA_PUT_U32(skb, CTRL_ATTR_VERSION, family->version);
503         NLA_PUT_U32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize);
504         NLA_PUT_U32(skb, CTRL_ATTR_MAXATTR, family->maxattr);
505
506         if (!list_empty(&family->ops_list)) {
507                 struct nlattr *nla_ops;
508                 struct genl_ops *ops;
509                 int idx = 1;
510
511                 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
512                 if (nla_ops == NULL)
513                         goto nla_put_failure;
514
515                 list_for_each_entry(ops, &family->ops_list, ops_list) {
516                         struct nlattr *nest;
517
518                         nest = nla_nest_start(skb, idx++);
519                         if (nest == NULL)
520                                 goto nla_put_failure;
521
522                         NLA_PUT_U32(skb, CTRL_ATTR_OP_ID, ops->cmd);
523                         NLA_PUT_U32(skb, CTRL_ATTR_OP_FLAGS, ops->flags);
524
525                         nla_nest_end(skb, nest);
526                 }
527
528                 nla_nest_end(skb, nla_ops);
529         }
530
531         if (!list_empty(&family->mcast_groups)) {
532                 struct genl_multicast_group *grp;
533                 struct nlattr *nla_grps;
534                 int idx = 1;
535
536                 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
537                 if (nla_grps == NULL)
538                         goto nla_put_failure;
539
540                 list_for_each_entry(grp, &family->mcast_groups, list) {
541                         struct nlattr *nest;
542
543                         nest = nla_nest_start(skb, idx++);
544                         if (nest == NULL)
545                                 goto nla_put_failure;
546
547                         NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
548                         NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
549                                        grp->name);
550
551                         nla_nest_end(skb, nest);
552                 }
553                 nla_nest_end(skb, nla_grps);
554         }
555
556         return genlmsg_end(skb, hdr);
557
558 nla_put_failure:
559         return genlmsg_cancel(skb, hdr);
560 }
561
562 static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 pid,
563                                 u32 seq, u32 flags, struct sk_buff *skb,
564                                 u8 cmd)
565 {
566         void *hdr;
567         struct nlattr *nla_grps;
568         struct nlattr *nest;
569
570         hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
571         if (hdr == NULL)
572                 return -1;
573
574         NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, grp->family->name);
575         NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, grp->family->id);
576
577         nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
578         if (nla_grps == NULL)
579                 goto nla_put_failure;
580
581         nest = nla_nest_start(skb, 1);
582         if (nest == NULL)
583                 goto nla_put_failure;
584
585         NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
586         NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
587                        grp->name);
588
589         nla_nest_end(skb, nest);
590         nla_nest_end(skb, nla_grps);
591
592         return genlmsg_end(skb, hdr);
593
594 nla_put_failure:
595         return genlmsg_cancel(skb, hdr);
596 }
597
598 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
599 {
600
601         int i, n = 0;
602         struct genl_family *rt;
603         int chains_to_skip = cb->args[0];
604         int fams_to_skip = cb->args[1];
605
606         if (chains_to_skip != 0)
607                 genl_lock();
608
609         for (i = 0; i < GENL_FAM_TAB_SIZE; i++) {
610                 if (i < chains_to_skip)
611                         continue;
612                 n = 0;
613                 list_for_each_entry(rt, genl_family_chain(i), family_list) {
614                         if (++n < fams_to_skip)
615                                 continue;
616                         if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).pid,
617                                            cb->nlh->nlmsg_seq, NLM_F_MULTI,
618                                            skb, CTRL_CMD_NEWFAMILY) < 0)
619                                 goto errout;
620                 }
621
622                 fams_to_skip = 0;
623         }
624
625 errout:
626         if (chains_to_skip != 0)
627                 genl_unlock();
628
629         cb->args[0] = i;
630         cb->args[1] = n;
631
632         return skb->len;
633 }
634
635 static struct sk_buff *ctrl_build_family_msg(struct genl_family *family,
636                                              u32 pid, int seq, u8 cmd)
637 {
638         struct sk_buff *skb;
639         int err;
640
641         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
642         if (skb == NULL)
643                 return ERR_PTR(-ENOBUFS);
644
645         err = ctrl_fill_info(family, pid, seq, 0, skb, cmd);
646         if (err < 0) {
647                 nlmsg_free(skb);
648                 return ERR_PTR(err);
649         }
650
651         return skb;
652 }
653
654 static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_multicast_group *grp,
655                                             u32 pid, int seq, u8 cmd)
656 {
657         struct sk_buff *skb;
658         int err;
659
660         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
661         if (skb == NULL)
662                 return ERR_PTR(-ENOBUFS);
663
664         err = ctrl_fill_mcgrp_info(grp, pid, seq, 0, skb, cmd);
665         if (err < 0) {
666                 nlmsg_free(skb);
667                 return ERR_PTR(err);
668         }
669
670         return skb;
671 }
672
673 static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
674         [CTRL_ATTR_FAMILY_ID]   = { .type = NLA_U16 },
675         [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
676                                     .len = GENL_NAMSIZ - 1 },
677 };
678
679 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
680 {
681         struct sk_buff *msg;
682         struct genl_family *res = NULL;
683         int err = -EINVAL;
684
685         if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
686                 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
687                 res = genl_family_find_byid(id);
688         }
689
690         if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
691                 char *name;
692
693                 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
694                 res = genl_family_find_byname(name);
695         }
696
697         if (res == NULL) {
698                 err = -ENOENT;
699                 goto errout;
700         }
701
702         msg = ctrl_build_family_msg(res, info->snd_pid, info->snd_seq,
703                                     CTRL_CMD_NEWFAMILY);
704         if (IS_ERR(msg)) {
705                 err = PTR_ERR(msg);
706                 goto errout;
707         }
708
709         err = genlmsg_reply(msg, info);
710 errout:
711         return err;
712 }
713
714 static int genl_ctrl_event(int event, void *data)
715 {
716         struct sk_buff *msg;
717
718         if (genl_sock == NULL)
719                 return 0;
720
721         switch (event) {
722         case CTRL_CMD_NEWFAMILY:
723         case CTRL_CMD_DELFAMILY:
724                 msg = ctrl_build_family_msg(data, 0, 0, event);
725                 if (IS_ERR(msg))
726                         return PTR_ERR(msg);
727
728                 genlmsg_multicast(msg, 0, GENL_ID_CTRL, GFP_KERNEL);
729                 break;
730         case CTRL_CMD_NEWMCAST_GRP:
731         case CTRL_CMD_DELMCAST_GRP:
732                 msg = ctrl_build_mcgrp_msg(data, 0, 0, event);
733                 if (IS_ERR(msg))
734                         return PTR_ERR(msg);
735
736                 genlmsg_multicast(msg, 0, GENL_ID_CTRL, GFP_KERNEL);
737                 break;
738         }
739
740         return 0;
741 }
742
743 static struct genl_ops genl_ctrl_ops = {
744         .cmd            = CTRL_CMD_GETFAMILY,
745         .doit           = ctrl_getfamily,
746         .dumpit         = ctrl_dumpfamily,
747         .policy         = ctrl_policy,
748 };
749
750 static struct genl_multicast_group notify_grp = {
751         .name           = "notify",
752 };
753
754 static int __init genl_init(void)
755 {
756         int i, err;
757
758         for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
759                 INIT_LIST_HEAD(&family_ht[i]);
760
761         err = genl_register_family(&genl_ctrl);
762         if (err < 0)
763                 goto errout;
764
765         err = genl_register_ops(&genl_ctrl, &genl_ctrl_ops);
766         if (err < 0)
767                 goto errout_register;
768
769         netlink_set_nonroot(NETLINK_GENERIC, NL_NONROOT_RECV);
770
771         /* we'll bump the group number right afterwards */
772         genl_sock = netlink_kernel_create(&init_net, NETLINK_GENERIC, 0,
773                                           genl_rcv, NULL, THIS_MODULE);
774         if (genl_sock == NULL)
775                 panic("GENL: Cannot initialize generic netlink\n");
776
777         err = genl_register_mc_group(&genl_ctrl, &notify_grp);
778         if (err < 0)
779                 goto errout_register;
780
781         return 0;
782
783 errout_register:
784         genl_unregister_family(&genl_ctrl);
785 errout:
786         panic("GENL: Cannot register controller: %d\n", err);
787 }
788
789 subsys_initcall(genl_init);
790
791 EXPORT_SYMBOL(genl_sock);
792 EXPORT_SYMBOL(genl_register_ops);
793 EXPORT_SYMBOL(genl_unregister_ops);
794 EXPORT_SYMBOL(genl_register_family);
795 EXPORT_SYMBOL(genl_unregister_family);