ipv4: tcp: set unicast_sock uc_ttl to -1
[linux-3.10.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 #ifdef CONFIG_PROVE_LOCKING
37 int lockdep_genl_is_held(void)
38 {
39         return lockdep_is_held(&genl_mutex);
40 }
41 EXPORT_SYMBOL(lockdep_genl_is_held);
42 #endif
43
44 #define GENL_FAM_TAB_SIZE       16
45 #define GENL_FAM_TAB_MASK       (GENL_FAM_TAB_SIZE - 1)
46
47 static struct list_head family_ht[GENL_FAM_TAB_SIZE];
48 /*
49  * Bitmap of multicast groups that are currently in use.
50  *
51  * To avoid an allocation at boot of just one unsigned long,
52  * declare it global instead.
53  * Bit 0 is marked as already used since group 0 is invalid.
54  */
55 static unsigned long mc_group_start = 0x1;
56 static unsigned long *mc_groups = &mc_group_start;
57 static unsigned long mc_groups_longs = 1;
58
59 static int genl_ctrl_event(int event, void *data);
60
61 static inline unsigned int genl_family_hash(unsigned int id)
62 {
63         return id & GENL_FAM_TAB_MASK;
64 }
65
66 static inline struct list_head *genl_family_chain(unsigned int id)
67 {
68         return &family_ht[genl_family_hash(id)];
69 }
70
71 static struct genl_family *genl_family_find_byid(unsigned int id)
72 {
73         struct genl_family *f;
74
75         list_for_each_entry(f, genl_family_chain(id), family_list)
76                 if (f->id == id)
77                         return f;
78
79         return NULL;
80 }
81
82 static struct genl_family *genl_family_find_byname(char *name)
83 {
84         struct genl_family *f;
85         int i;
86
87         for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
88                 list_for_each_entry(f, genl_family_chain(i), family_list)
89                         if (strcmp(f->name, name) == 0)
90                                 return f;
91
92         return NULL;
93 }
94
95 static struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family)
96 {
97         struct genl_ops *ops;
98
99         list_for_each_entry(ops, &family->ops_list, ops_list)
100                 if (ops->cmd == cmd)
101                         return ops;
102
103         return NULL;
104 }
105
106 /* Of course we are going to have problems once we hit
107  * 2^16 alive types, but that can only happen by year 2K
108 */
109 static u16 genl_generate_id(void)
110 {
111         static u16 id_gen_idx = GENL_MIN_ID;
112         int i;
113
114         for (i = 0; i <= GENL_MAX_ID - GENL_MIN_ID; i++) {
115                 if (!genl_family_find_byid(id_gen_idx))
116                         return id_gen_idx;
117                 if (++id_gen_idx > GENL_MAX_ID)
118                         id_gen_idx = GENL_MIN_ID;
119         }
120
121         return 0;
122 }
123
124 static struct genl_multicast_group notify_grp;
125
126 /**
127  * genl_register_mc_group - register a multicast group
128  *
129  * Registers the specified multicast group and notifies userspace
130  * about the new group.
131  *
132  * Returns 0 on success or a negative error code.
133  *
134  * @family: The generic netlink family the group shall be registered for.
135  * @grp: The group to register, must have a name.
136  */
137 int genl_register_mc_group(struct genl_family *family,
138                            struct genl_multicast_group *grp)
139 {
140         int id;
141         unsigned long *new_groups;
142         int err = 0;
143
144         BUG_ON(grp->name[0] == '\0');
145
146         genl_lock();
147
148         /* special-case our own group */
149         if (grp == &notify_grp)
150                 id = GENL_ID_CTRL;
151         else
152                 id = find_first_zero_bit(mc_groups,
153                                          mc_groups_longs * BITS_PER_LONG);
154
155
156         if (id >= mc_groups_longs * BITS_PER_LONG) {
157                 size_t nlen = (mc_groups_longs + 1) * sizeof(unsigned long);
158
159                 if (mc_groups == &mc_group_start) {
160                         new_groups = kzalloc(nlen, GFP_KERNEL);
161                         if (!new_groups) {
162                                 err = -ENOMEM;
163                                 goto out;
164                         }
165                         mc_groups = new_groups;
166                         *mc_groups = mc_group_start;
167                 } else {
168                         new_groups = krealloc(mc_groups, nlen, GFP_KERNEL);
169                         if (!new_groups) {
170                                 err = -ENOMEM;
171                                 goto out;
172                         }
173                         mc_groups = new_groups;
174                         mc_groups[mc_groups_longs] = 0;
175                 }
176                 mc_groups_longs++;
177         }
178
179         if (family->netnsok) {
180                 struct net *net;
181
182                 netlink_table_grab();
183                 rcu_read_lock();
184                 for_each_net_rcu(net) {
185                         err = __netlink_change_ngroups(net->genl_sock,
186                                         mc_groups_longs * BITS_PER_LONG);
187                         if (err) {
188                                 /*
189                                  * No need to roll back, can only fail if
190                                  * memory allocation fails and then the
191                                  * number of _possible_ groups has been
192                                  * increased on some sockets which is ok.
193                                  */
194                                 rcu_read_unlock();
195                                 netlink_table_ungrab();
196                                 goto out;
197                         }
198                 }
199                 rcu_read_unlock();
200                 netlink_table_ungrab();
201         } else {
202                 err = netlink_change_ngroups(init_net.genl_sock,
203                                              mc_groups_longs * BITS_PER_LONG);
204                 if (err)
205                         goto out;
206         }
207
208         grp->id = id;
209         set_bit(id, mc_groups);
210         list_add_tail(&grp->list, &family->mcast_groups);
211         grp->family = family;
212
213         genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, grp);
214  out:
215         genl_unlock();
216         return err;
217 }
218 EXPORT_SYMBOL(genl_register_mc_group);
219
220 static void __genl_unregister_mc_group(struct genl_family *family,
221                                        struct genl_multicast_group *grp)
222 {
223         struct net *net;
224         BUG_ON(grp->family != family);
225
226         netlink_table_grab();
227         rcu_read_lock();
228         for_each_net_rcu(net)
229                 __netlink_clear_multicast_users(net->genl_sock, grp->id);
230         rcu_read_unlock();
231         netlink_table_ungrab();
232
233         clear_bit(grp->id, mc_groups);
234         list_del(&grp->list);
235         genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, grp);
236         grp->id = 0;
237         grp->family = NULL;
238 }
239
240 /**
241  * genl_unregister_mc_group - unregister a multicast group
242  *
243  * Unregisters the specified multicast group and notifies userspace
244  * about it. All current listeners on the group are removed.
245  *
246  * Note: It is not necessary to unregister all multicast groups before
247  *       unregistering the family, unregistering the family will cause
248  *       all assigned multicast groups to be unregistered automatically.
249  *
250  * @family: Generic netlink family the group belongs to.
251  * @grp: The group to unregister, must have been registered successfully
252  *       previously.
253  */
254 void genl_unregister_mc_group(struct genl_family *family,
255                               struct genl_multicast_group *grp)
256 {
257         genl_lock();
258         __genl_unregister_mc_group(family, grp);
259         genl_unlock();
260 }
261 EXPORT_SYMBOL(genl_unregister_mc_group);
262
263 static void genl_unregister_mc_groups(struct genl_family *family)
264 {
265         struct genl_multicast_group *grp, *tmp;
266
267         list_for_each_entry_safe(grp, tmp, &family->mcast_groups, list)
268                 __genl_unregister_mc_group(family, grp);
269 }
270
271 /**
272  * genl_register_ops - register generic netlink operations
273  * @family: generic netlink family
274  * @ops: operations to be registered
275  *
276  * Registers the specified operations and assigns them to the specified
277  * family. Either a doit or dumpit callback must be specified or the
278  * operation will fail. Only one operation structure per command
279  * identifier may be registered.
280  *
281  * See include/net/genetlink.h for more documenation on the operations
282  * structure.
283  *
284  * Returns 0 on success or a negative error code.
285  */
286 int genl_register_ops(struct genl_family *family, struct genl_ops *ops)
287 {
288         int err = -EINVAL;
289
290         if (ops->dumpit == NULL && ops->doit == NULL)
291                 goto errout;
292
293         if (genl_get_cmd(ops->cmd, family)) {
294                 err = -EEXIST;
295                 goto errout;
296         }
297
298         if (ops->dumpit)
299                 ops->flags |= GENL_CMD_CAP_DUMP;
300         if (ops->doit)
301                 ops->flags |= GENL_CMD_CAP_DO;
302         if (ops->policy)
303                 ops->flags |= GENL_CMD_CAP_HASPOL;
304
305         genl_lock();
306         list_add_tail(&ops->ops_list, &family->ops_list);
307         genl_unlock();
308
309         genl_ctrl_event(CTRL_CMD_NEWOPS, ops);
310         err = 0;
311 errout:
312         return err;
313 }
314 EXPORT_SYMBOL(genl_register_ops);
315
316 /**
317  * genl_unregister_ops - unregister generic netlink operations
318  * @family: generic netlink family
319  * @ops: operations to be unregistered
320  *
321  * Unregisters the specified operations and unassigns them from the
322  * specified family. The operation blocks until the current message
323  * processing has finished and doesn't start again until the
324  * unregister process has finished.
325  *
326  * Note: It is not necessary to unregister all operations before
327  *       unregistering the family, unregistering the family will cause
328  *       all assigned operations to be unregistered automatically.
329  *
330  * Returns 0 on success or a negative error code.
331  */
332 int genl_unregister_ops(struct genl_family *family, struct genl_ops *ops)
333 {
334         struct genl_ops *rc;
335
336         genl_lock();
337         list_for_each_entry(rc, &family->ops_list, ops_list) {
338                 if (rc == ops) {
339                         list_del(&ops->ops_list);
340                         genl_unlock();
341                         genl_ctrl_event(CTRL_CMD_DELOPS, ops);
342                         return 0;
343                 }
344         }
345         genl_unlock();
346
347         return -ENOENT;
348 }
349 EXPORT_SYMBOL(genl_unregister_ops);
350
351 /**
352  * genl_register_family - register a generic netlink family
353  * @family: generic netlink family
354  *
355  * Registers the specified family after validating it first. Only one
356  * family may be registered with the same family name or identifier.
357  * The family id may equal GENL_ID_GENERATE causing an unique id to
358  * be automatically generated and assigned.
359  *
360  * Return 0 on success or a negative error code.
361  */
362 int genl_register_family(struct genl_family *family)
363 {
364         int err = -EINVAL;
365
366         if (family->id && family->id < GENL_MIN_ID)
367                 goto errout;
368
369         if (family->id > GENL_MAX_ID)
370                 goto errout;
371
372         INIT_LIST_HEAD(&family->ops_list);
373         INIT_LIST_HEAD(&family->mcast_groups);
374
375         genl_lock();
376
377         if (genl_family_find_byname(family->name)) {
378                 err = -EEXIST;
379                 goto errout_locked;
380         }
381
382         if (family->id == GENL_ID_GENERATE) {
383                 u16 newid = genl_generate_id();
384
385                 if (!newid) {
386                         err = -ENOMEM;
387                         goto errout_locked;
388                 }
389
390                 family->id = newid;
391         } else if (genl_family_find_byid(family->id)) {
392                 err = -EEXIST;
393                 goto errout_locked;
394         }
395
396         if (family->maxattr) {
397                 family->attrbuf = kmalloc((family->maxattr+1) *
398                                         sizeof(struct nlattr *), GFP_KERNEL);
399                 if (family->attrbuf == NULL) {
400                         err = -ENOMEM;
401                         goto errout_locked;
402                 }
403         } else
404                 family->attrbuf = NULL;
405
406         list_add_tail(&family->family_list, genl_family_chain(family->id));
407         genl_unlock();
408
409         genl_ctrl_event(CTRL_CMD_NEWFAMILY, family);
410
411         return 0;
412
413 errout_locked:
414         genl_unlock();
415 errout:
416         return err;
417 }
418 EXPORT_SYMBOL(genl_register_family);
419
420 /**
421  * genl_register_family_with_ops - register a generic netlink family
422  * @family: generic netlink family
423  * @ops: operations to be registered
424  * @n_ops: number of elements to register
425  *
426  * Registers the specified family and operations from the specified table.
427  * Only one family may be registered with the same family name or identifier.
428  *
429  * The family id may equal GENL_ID_GENERATE causing an unique id to
430  * be automatically generated and assigned.
431  *
432  * Either a doit or dumpit callback must be specified for every registered
433  * operation or the function will fail. Only one operation structure per
434  * command identifier may be registered.
435  *
436  * See include/net/genetlink.h for more documenation on the operations
437  * structure.
438  *
439  * This is equivalent to calling genl_register_family() followed by
440  * genl_register_ops() for every operation entry in the table taking
441  * care to unregister the family on error path.
442  *
443  * Return 0 on success or a negative error code.
444  */
445 int genl_register_family_with_ops(struct genl_family *family,
446         struct genl_ops *ops, size_t n_ops)
447 {
448         int err, i;
449
450         err = genl_register_family(family);
451         if (err)
452                 return err;
453
454         for (i = 0; i < n_ops; ++i, ++ops) {
455                 err = genl_register_ops(family, ops);
456                 if (err)
457                         goto err_out;
458         }
459         return 0;
460 err_out:
461         genl_unregister_family(family);
462         return err;
463 }
464 EXPORT_SYMBOL(genl_register_family_with_ops);
465
466 /**
467  * genl_unregister_family - unregister generic netlink family
468  * @family: generic netlink family
469  *
470  * Unregisters the specified family.
471  *
472  * Returns 0 on success or a negative error code.
473  */
474 int genl_unregister_family(struct genl_family *family)
475 {
476         struct genl_family *rc;
477
478         genl_lock();
479
480         genl_unregister_mc_groups(family);
481
482         list_for_each_entry(rc, genl_family_chain(family->id), family_list) {
483                 if (family->id != rc->id || strcmp(rc->name, family->name))
484                         continue;
485
486                 list_del(&rc->family_list);
487                 INIT_LIST_HEAD(&family->ops_list);
488                 genl_unlock();
489
490                 kfree(family->attrbuf);
491                 genl_ctrl_event(CTRL_CMD_DELFAMILY, family);
492                 return 0;
493         }
494
495         genl_unlock();
496
497         return -ENOENT;
498 }
499 EXPORT_SYMBOL(genl_unregister_family);
500
501 /**
502  * genlmsg_put - Add generic netlink header to netlink message
503  * @skb: socket buffer holding the message
504  * @pid: netlink pid the message is addressed to
505  * @seq: sequence number (usually the one of the sender)
506  * @family: generic netlink family
507  * @flags: netlink message flags
508  * @cmd: generic netlink command
509  *
510  * Returns pointer to user specific header
511  */
512 void *genlmsg_put(struct sk_buff *skb, u32 pid, u32 seq,
513                                 struct genl_family *family, int flags, u8 cmd)
514 {
515         struct nlmsghdr *nlh;
516         struct genlmsghdr *hdr;
517
518         nlh = nlmsg_put(skb, pid, seq, family->id, GENL_HDRLEN +
519                         family->hdrsize, flags);
520         if (nlh == NULL)
521                 return NULL;
522
523         hdr = nlmsg_data(nlh);
524         hdr->cmd = cmd;
525         hdr->version = family->version;
526         hdr->reserved = 0;
527
528         return (char *) hdr + GENL_HDRLEN;
529 }
530 EXPORT_SYMBOL(genlmsg_put);
531
532 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
533 {
534         struct genl_ops *ops;
535         struct genl_family *family;
536         struct net *net = sock_net(skb->sk);
537         struct genl_info info;
538         struct genlmsghdr *hdr = nlmsg_data(nlh);
539         int hdrlen, err;
540
541         family = genl_family_find_byid(nlh->nlmsg_type);
542         if (family == NULL)
543                 return -ENOENT;
544
545         /* this family doesn't exist in this netns */
546         if (!family->netnsok && !net_eq(net, &init_net))
547                 return -ENOENT;
548
549         hdrlen = GENL_HDRLEN + family->hdrsize;
550         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
551                 return -EINVAL;
552
553         ops = genl_get_cmd(hdr->cmd, family);
554         if (ops == NULL)
555                 return -EOPNOTSUPP;
556
557         if ((ops->flags & GENL_ADMIN_PERM) &&
558             !capable(CAP_NET_ADMIN))
559                 return -EPERM;
560
561         if (nlh->nlmsg_flags & NLM_F_DUMP) {
562                 if (ops->dumpit == NULL)
563                         return -EOPNOTSUPP;
564
565                 genl_unlock();
566                 {
567                         struct netlink_dump_control c = {
568                                 .dump = ops->dumpit,
569                                 .done = ops->done,
570                         };
571                         err = netlink_dump_start(net->genl_sock, skb, nlh, &c);
572                 }
573                 genl_lock();
574                 return err;
575         }
576
577         if (ops->doit == NULL)
578                 return -EOPNOTSUPP;
579
580         if (family->attrbuf) {
581                 err = nlmsg_parse(nlh, hdrlen, family->attrbuf, family->maxattr,
582                                   ops->policy);
583                 if (err < 0)
584                         return err;
585         }
586
587         info.snd_seq = nlh->nlmsg_seq;
588         info.snd_pid = NETLINK_CB(skb).pid;
589         info.nlhdr = nlh;
590         info.genlhdr = nlmsg_data(nlh);
591         info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
592         info.attrs = family->attrbuf;
593         genl_info_net_set(&info, net);
594         memset(&info.user_ptr, 0, sizeof(info.user_ptr));
595
596         if (family->pre_doit) {
597                 err = family->pre_doit(ops, skb, &info);
598                 if (err)
599                         return err;
600         }
601
602         err = ops->doit(skb, &info);
603
604         if (family->post_doit)
605                 family->post_doit(ops, skb, &info);
606
607         return err;
608 }
609
610 static void genl_rcv(struct sk_buff *skb)
611 {
612         genl_lock();
613         netlink_rcv_skb(skb, &genl_rcv_msg);
614         genl_unlock();
615 }
616
617 /**************************************************************************
618  * Controller
619  **************************************************************************/
620
621 static struct genl_family genl_ctrl = {
622         .id = GENL_ID_CTRL,
623         .name = "nlctrl",
624         .version = 0x2,
625         .maxattr = CTRL_ATTR_MAX,
626         .netnsok = true,
627 };
628
629 static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
630                           u32 flags, struct sk_buff *skb, u8 cmd)
631 {
632         void *hdr;
633
634         hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
635         if (hdr == NULL)
636                 return -1;
637
638         if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
639             nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) ||
640             nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) ||
641             nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) ||
642             nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr))
643                 goto nla_put_failure;
644
645         if (!list_empty(&family->ops_list)) {
646                 struct nlattr *nla_ops;
647                 struct genl_ops *ops;
648                 int idx = 1;
649
650                 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
651                 if (nla_ops == NULL)
652                         goto nla_put_failure;
653
654                 list_for_each_entry(ops, &family->ops_list, ops_list) {
655                         struct nlattr *nest;
656
657                         nest = nla_nest_start(skb, idx++);
658                         if (nest == NULL)
659                                 goto nla_put_failure;
660
661                         if (nla_put_u32(skb, CTRL_ATTR_OP_ID, ops->cmd) ||
662                             nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, ops->flags))
663                                 goto nla_put_failure;
664
665                         nla_nest_end(skb, nest);
666                 }
667
668                 nla_nest_end(skb, nla_ops);
669         }
670
671         if (!list_empty(&family->mcast_groups)) {
672                 struct genl_multicast_group *grp;
673                 struct nlattr *nla_grps;
674                 int idx = 1;
675
676                 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
677                 if (nla_grps == NULL)
678                         goto nla_put_failure;
679
680                 list_for_each_entry(grp, &family->mcast_groups, list) {
681                         struct nlattr *nest;
682
683                         nest = nla_nest_start(skb, idx++);
684                         if (nest == NULL)
685                                 goto nla_put_failure;
686
687                         if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id) ||
688                             nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
689                                            grp->name))
690                                 goto nla_put_failure;
691
692                         nla_nest_end(skb, nest);
693                 }
694                 nla_nest_end(skb, nla_grps);
695         }
696
697         return genlmsg_end(skb, hdr);
698
699 nla_put_failure:
700         genlmsg_cancel(skb, hdr);
701         return -EMSGSIZE;
702 }
703
704 static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 pid,
705                                 u32 seq, u32 flags, struct sk_buff *skb,
706                                 u8 cmd)
707 {
708         void *hdr;
709         struct nlattr *nla_grps;
710         struct nlattr *nest;
711
712         hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
713         if (hdr == NULL)
714                 return -1;
715
716         if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, grp->family->name) ||
717             nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, grp->family->id))
718                 goto nla_put_failure;
719
720         nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
721         if (nla_grps == NULL)
722                 goto nla_put_failure;
723
724         nest = nla_nest_start(skb, 1);
725         if (nest == NULL)
726                 goto nla_put_failure;
727
728         if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id) ||
729             nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
730                            grp->name))
731                 goto nla_put_failure;
732
733         nla_nest_end(skb, nest);
734         nla_nest_end(skb, nla_grps);
735
736         return genlmsg_end(skb, hdr);
737
738 nla_put_failure:
739         genlmsg_cancel(skb, hdr);
740         return -EMSGSIZE;
741 }
742
743 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
744 {
745
746         int i, n = 0;
747         struct genl_family *rt;
748         struct net *net = sock_net(skb->sk);
749         int chains_to_skip = cb->args[0];
750         int fams_to_skip = cb->args[1];
751
752         for (i = chains_to_skip; i < GENL_FAM_TAB_SIZE; i++) {
753                 n = 0;
754                 list_for_each_entry(rt, genl_family_chain(i), family_list) {
755                         if (!rt->netnsok && !net_eq(net, &init_net))
756                                 continue;
757                         if (++n < fams_to_skip)
758                                 continue;
759                         if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).pid,
760                                            cb->nlh->nlmsg_seq, NLM_F_MULTI,
761                                            skb, CTRL_CMD_NEWFAMILY) < 0)
762                                 goto errout;
763                 }
764
765                 fams_to_skip = 0;
766         }
767
768 errout:
769         cb->args[0] = i;
770         cb->args[1] = n;
771
772         return skb->len;
773 }
774
775 static struct sk_buff *ctrl_build_family_msg(struct genl_family *family,
776                                              u32 pid, int seq, u8 cmd)
777 {
778         struct sk_buff *skb;
779         int err;
780
781         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
782         if (skb == NULL)
783                 return ERR_PTR(-ENOBUFS);
784
785         err = ctrl_fill_info(family, pid, seq, 0, skb, cmd);
786         if (err < 0) {
787                 nlmsg_free(skb);
788                 return ERR_PTR(err);
789         }
790
791         return skb;
792 }
793
794 static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_multicast_group *grp,
795                                             u32 pid, int seq, u8 cmd)
796 {
797         struct sk_buff *skb;
798         int err;
799
800         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
801         if (skb == NULL)
802                 return ERR_PTR(-ENOBUFS);
803
804         err = ctrl_fill_mcgrp_info(grp, pid, seq, 0, skb, cmd);
805         if (err < 0) {
806                 nlmsg_free(skb);
807                 return ERR_PTR(err);
808         }
809
810         return skb;
811 }
812
813 static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
814         [CTRL_ATTR_FAMILY_ID]   = { .type = NLA_U16 },
815         [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
816                                     .len = GENL_NAMSIZ - 1 },
817 };
818
819 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
820 {
821         struct sk_buff *msg;
822         struct genl_family *res = NULL;
823         int err = -EINVAL;
824
825         if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
826                 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
827                 res = genl_family_find_byid(id);
828                 err = -ENOENT;
829         }
830
831         if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
832                 char *name;
833
834                 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
835                 res = genl_family_find_byname(name);
836 #ifdef CONFIG_MODULES
837                 if (res == NULL) {
838                         genl_unlock();
839                         request_module("net-pf-%d-proto-%d-family-%s",
840                                        PF_NETLINK, NETLINK_GENERIC, name);
841                         genl_lock();
842                         res = genl_family_find_byname(name);
843                 }
844 #endif
845                 err = -ENOENT;
846         }
847
848         if (res == NULL)
849                 return err;
850
851         if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) {
852                 /* family doesn't exist here */
853                 return -ENOENT;
854         }
855
856         msg = ctrl_build_family_msg(res, info->snd_pid, info->snd_seq,
857                                     CTRL_CMD_NEWFAMILY);
858         if (IS_ERR(msg))
859                 return PTR_ERR(msg);
860
861         return genlmsg_reply(msg, info);
862 }
863
864 static int genl_ctrl_event(int event, void *data)
865 {
866         struct sk_buff *msg;
867         struct genl_family *family;
868         struct genl_multicast_group *grp;
869
870         /* genl is still initialising */
871         if (!init_net.genl_sock)
872                 return 0;
873
874         switch (event) {
875         case CTRL_CMD_NEWFAMILY:
876         case CTRL_CMD_DELFAMILY:
877                 family = data;
878                 msg = ctrl_build_family_msg(family, 0, 0, event);
879                 break;
880         case CTRL_CMD_NEWMCAST_GRP:
881         case CTRL_CMD_DELMCAST_GRP:
882                 grp = data;
883                 family = grp->family;
884                 msg = ctrl_build_mcgrp_msg(data, 0, 0, event);
885                 break;
886         default:
887                 return -EINVAL;
888         }
889
890         if (IS_ERR(msg))
891                 return PTR_ERR(msg);
892
893         if (!family->netnsok) {
894                 genlmsg_multicast_netns(&init_net, msg, 0,
895                                         GENL_ID_CTRL, GFP_KERNEL);
896         } else {
897                 rcu_read_lock();
898                 genlmsg_multicast_allns(msg, 0, GENL_ID_CTRL, GFP_ATOMIC);
899                 rcu_read_unlock();
900         }
901
902         return 0;
903 }
904
905 static struct genl_ops genl_ctrl_ops = {
906         .cmd            = CTRL_CMD_GETFAMILY,
907         .doit           = ctrl_getfamily,
908         .dumpit         = ctrl_dumpfamily,
909         .policy         = ctrl_policy,
910 };
911
912 static struct genl_multicast_group notify_grp = {
913         .name           = "notify",
914 };
915
916 static int __net_init genl_pernet_init(struct net *net)
917 {
918         struct netlink_kernel_cfg cfg = {
919                 .input          = genl_rcv,
920                 .cb_mutex       = &genl_mutex,
921         };
922
923         /* we'll bump the group number right afterwards */
924         net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC,
925                                                THIS_MODULE, &cfg);
926
927         if (!net->genl_sock && net_eq(net, &init_net))
928                 panic("GENL: Cannot initialize generic netlink\n");
929
930         if (!net->genl_sock)
931                 return -ENOMEM;
932
933         return 0;
934 }
935
936 static void __net_exit genl_pernet_exit(struct net *net)
937 {
938         netlink_kernel_release(net->genl_sock);
939         net->genl_sock = NULL;
940 }
941
942 static struct pernet_operations genl_pernet_ops = {
943         .init = genl_pernet_init,
944         .exit = genl_pernet_exit,
945 };
946
947 static int __init genl_init(void)
948 {
949         int i, err;
950
951         for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
952                 INIT_LIST_HEAD(&family_ht[i]);
953
954         err = genl_register_family_with_ops(&genl_ctrl, &genl_ctrl_ops, 1);
955         if (err < 0)
956                 goto problem;
957
958         netlink_set_nonroot(NETLINK_GENERIC, NL_NONROOT_RECV);
959
960         err = register_pernet_subsys(&genl_pernet_ops);
961         if (err)
962                 goto problem;
963
964         err = genl_register_mc_group(&genl_ctrl, &notify_grp);
965         if (err < 0)
966                 goto problem;
967
968         return 0;
969
970 problem:
971         panic("GENL: Cannot register controller: %d\n", err);
972 }
973
974 subsys_initcall(genl_init);
975
976 static int genlmsg_mcast(struct sk_buff *skb, u32 pid, unsigned long group,
977                          gfp_t flags)
978 {
979         struct sk_buff *tmp;
980         struct net *net, *prev = NULL;
981         int err;
982
983         for_each_net_rcu(net) {
984                 if (prev) {
985                         tmp = skb_clone(skb, flags);
986                         if (!tmp) {
987                                 err = -ENOMEM;
988                                 goto error;
989                         }
990                         err = nlmsg_multicast(prev->genl_sock, tmp,
991                                               pid, group, flags);
992                         if (err)
993                                 goto error;
994                 }
995
996                 prev = net;
997         }
998
999         return nlmsg_multicast(prev->genl_sock, skb, pid, group, flags);
1000  error:
1001         kfree_skb(skb);
1002         return err;
1003 }
1004
1005 int genlmsg_multicast_allns(struct sk_buff *skb, u32 pid, unsigned int group,
1006                             gfp_t flags)
1007 {
1008         return genlmsg_mcast(skb, pid, group, flags);
1009 }
1010 EXPORT_SYMBOL(genlmsg_multicast_allns);
1011
1012 void genl_notify(struct sk_buff *skb, struct net *net, u32 pid, u32 group,
1013                  struct nlmsghdr *nlh, gfp_t flags)
1014 {
1015         struct sock *sk = net->genl_sock;
1016         int report = 0;
1017
1018         if (nlh)
1019                 report = nlmsg_report(nlh);
1020
1021         nlmsg_notify(sk, skb, pid, group, report, flags);
1022 }
1023 EXPORT_SYMBOL(genl_notify);