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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 <linux/rwsem.h> | |
20 | #include <net/sock.h> | |
21 | #include <net/genetlink.h> | |
22 | ||
23 | static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */ | |
24 | static DECLARE_RWSEM(cb_lock); | |
25 | ||
26 | void genl_lock(void) | |
27 | { | |
28 | mutex_lock(&genl_mutex); | |
29 | } | |
30 | EXPORT_SYMBOL(genl_lock); | |
31 | ||
32 | void genl_unlock(void) | |
33 | { | |
34 | mutex_unlock(&genl_mutex); | |
35 | } | |
36 | EXPORT_SYMBOL(genl_unlock); | |
37 | ||
38 | #ifdef CONFIG_LOCKDEP | |
39 | int lockdep_genl_is_held(void) | |
40 | { | |
41 | return lockdep_is_held(&genl_mutex); | |
42 | } | |
43 | EXPORT_SYMBOL(lockdep_genl_is_held); | |
44 | #endif | |
45 | ||
46 | static void genl_lock_all(void) | |
47 | { | |
48 | down_write(&cb_lock); | |
49 | genl_lock(); | |
50 | } | |
51 | ||
52 | static void genl_unlock_all(void) | |
53 | { | |
54 | genl_unlock(); | |
55 | up_write(&cb_lock); | |
56 | } | |
57 | ||
58 | #define GENL_FAM_TAB_SIZE 16 | |
59 | #define GENL_FAM_TAB_MASK (GENL_FAM_TAB_SIZE - 1) | |
60 | ||
61 | static struct list_head family_ht[GENL_FAM_TAB_SIZE]; | |
62 | /* | |
63 | * Bitmap of multicast groups that are currently in use. | |
64 | * | |
65 | * To avoid an allocation at boot of just one unsigned long, | |
66 | * declare it global instead. | |
67 | * Bit 0 is marked as already used since group 0 is invalid. | |
68 | * Bit 1 is marked as already used since the drop-monitor code | |
69 | * abuses the API and thinks it can statically use group 1. | |
70 | * That group will typically conflict with other groups that | |
71 | * any proper users use. | |
72 | * Bit 16 is marked as used since it's used for generic netlink | |
73 | * and the code no longer marks pre-reserved IDs as used. | |
74 | * Bit 17 is marked as already used since the VFS quota code | |
75 | * also abused this API and relied on family == group ID, we | |
76 | * cater to that by giving it a static family and group ID. | |
77 | * Bit 18 is marked as already used since the PMCRAID driver | |
78 | * did the same thing as the VFS quota code (maybe copied?) | |
79 | */ | |
80 | static unsigned long mc_group_start = 0x3 | BIT(GENL_ID_CTRL) | | |
81 | BIT(GENL_ID_VFS_DQUOT) | | |
82 | BIT(GENL_ID_PMCRAID); | |
83 | static unsigned long *mc_groups = &mc_group_start; | |
84 | static unsigned long mc_groups_longs = 1; | |
85 | ||
86 | static int genl_ctrl_event(int event, struct genl_family *family, | |
87 | const struct genl_multicast_group *grp, | |
88 | int grp_id); | |
89 | ||
90 | static inline unsigned int genl_family_hash(unsigned int id) | |
91 | { | |
92 | return id & GENL_FAM_TAB_MASK; | |
93 | } | |
94 | ||
95 | static inline struct list_head *genl_family_chain(unsigned int id) | |
96 | { | |
97 | return &family_ht[genl_family_hash(id)]; | |
98 | } | |
99 | ||
100 | static struct genl_family *genl_family_find_byid(unsigned int id) | |
101 | { | |
102 | struct genl_family *f; | |
103 | ||
104 | list_for_each_entry(f, genl_family_chain(id), family_list) | |
105 | if (f->id == id) | |
106 | return f; | |
107 | ||
108 | return NULL; | |
109 | } | |
110 | ||
111 | static struct genl_family *genl_family_find_byname(char *name) | |
112 | { | |
113 | struct genl_family *f; | |
114 | int i; | |
115 | ||
116 | for (i = 0; i < GENL_FAM_TAB_SIZE; i++) | |
117 | list_for_each_entry(f, genl_family_chain(i), family_list) | |
118 | if (strcmp(f->name, name) == 0) | |
119 | return f; | |
120 | ||
121 | return NULL; | |
122 | } | |
123 | ||
124 | static const struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family) | |
125 | { | |
126 | int i; | |
127 | ||
128 | for (i = 0; i < family->n_ops; i++) | |
129 | if (family->ops[i].cmd == cmd) | |
130 | return &family->ops[i]; | |
131 | ||
132 | return NULL; | |
133 | } | |
134 | ||
135 | /* Of course we are going to have problems once we hit | |
136 | * 2^16 alive types, but that can only happen by year 2K | |
137 | */ | |
138 | static u16 genl_generate_id(void) | |
139 | { | |
140 | static u16 id_gen_idx = GENL_MIN_ID; | |
141 | int i; | |
142 | ||
143 | for (i = 0; i <= GENL_MAX_ID - GENL_MIN_ID; i++) { | |
144 | if (id_gen_idx != GENL_ID_VFS_DQUOT && | |
145 | id_gen_idx != GENL_ID_PMCRAID && | |
146 | !genl_family_find_byid(id_gen_idx)) | |
147 | return id_gen_idx; | |
148 | if (++id_gen_idx > GENL_MAX_ID) | |
149 | id_gen_idx = GENL_MIN_ID; | |
150 | } | |
151 | ||
152 | return 0; | |
153 | } | |
154 | ||
155 | static int genl_allocate_reserve_groups(int n_groups, int *first_id) | |
156 | { | |
157 | unsigned long *new_groups; | |
158 | int start = 0; | |
159 | int i; | |
160 | int id; | |
161 | bool fits; | |
162 | ||
163 | do { | |
164 | if (start == 0) | |
165 | id = find_first_zero_bit(mc_groups, | |
166 | mc_groups_longs * | |
167 | BITS_PER_LONG); | |
168 | else | |
169 | id = find_next_zero_bit(mc_groups, | |
170 | mc_groups_longs * BITS_PER_LONG, | |
171 | start); | |
172 | ||
173 | fits = true; | |
174 | for (i = id; | |
175 | i < min_t(int, id + n_groups, | |
176 | mc_groups_longs * BITS_PER_LONG); | |
177 | i++) { | |
178 | if (test_bit(i, mc_groups)) { | |
179 | start = i; | |
180 | fits = false; | |
181 | break; | |
182 | } | |
183 | } | |
184 | ||
185 | if (id >= mc_groups_longs * BITS_PER_LONG) { | |
186 | unsigned long new_longs = mc_groups_longs + | |
187 | BITS_TO_LONGS(n_groups); | |
188 | size_t nlen = new_longs * sizeof(unsigned long); | |
189 | ||
190 | if (mc_groups == &mc_group_start) { | |
191 | new_groups = kzalloc(nlen, GFP_KERNEL); | |
192 | if (!new_groups) | |
193 | return -ENOMEM; | |
194 | mc_groups = new_groups; | |
195 | *mc_groups = mc_group_start; | |
196 | } else { | |
197 | new_groups = krealloc(mc_groups, nlen, | |
198 | GFP_KERNEL); | |
199 | if (!new_groups) | |
200 | return -ENOMEM; | |
201 | mc_groups = new_groups; | |
202 | for (i = 0; i < BITS_TO_LONGS(n_groups); i++) | |
203 | mc_groups[mc_groups_longs + i] = 0; | |
204 | } | |
205 | mc_groups_longs = new_longs; | |
206 | } | |
207 | } while (!fits); | |
208 | ||
209 | for (i = id; i < id + n_groups; i++) | |
210 | set_bit(i, mc_groups); | |
211 | *first_id = id; | |
212 | return 0; | |
213 | } | |
214 | ||
215 | static struct genl_family genl_ctrl; | |
216 | ||
217 | static int genl_validate_assign_mc_groups(struct genl_family *family) | |
218 | { | |
219 | int first_id; | |
220 | int n_groups = family->n_mcgrps; | |
221 | int err = 0, i; | |
222 | bool groups_allocated = false; | |
223 | ||
224 | if (!n_groups) | |
225 | return 0; | |
226 | ||
227 | for (i = 0; i < n_groups; i++) { | |
228 | const struct genl_multicast_group *grp = &family->mcgrps[i]; | |
229 | ||
230 | if (WARN_ON(grp->name[0] == '\0')) | |
231 | return -EINVAL; | |
232 | if (WARN_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL)) | |
233 | return -EINVAL; | |
234 | } | |
235 | ||
236 | /* special-case our own group and hacks */ | |
237 | if (family == &genl_ctrl) { | |
238 | first_id = GENL_ID_CTRL; | |
239 | BUG_ON(n_groups != 1); | |
240 | } else if (strcmp(family->name, "NET_DM") == 0) { | |
241 | first_id = 1; | |
242 | BUG_ON(n_groups != 1); | |
243 | } else if (family->id == GENL_ID_VFS_DQUOT) { | |
244 | first_id = GENL_ID_VFS_DQUOT; | |
245 | BUG_ON(n_groups != 1); | |
246 | } else if (family->id == GENL_ID_PMCRAID) { | |
247 | first_id = GENL_ID_PMCRAID; | |
248 | BUG_ON(n_groups != 1); | |
249 | } else { | |
250 | groups_allocated = true; | |
251 | err = genl_allocate_reserve_groups(n_groups, &first_id); | |
252 | if (err) | |
253 | return err; | |
254 | } | |
255 | ||
256 | family->mcgrp_offset = first_id; | |
257 | ||
258 | /* if still initializing, can't and don't need to to realloc bitmaps */ | |
259 | if (!init_net.genl_sock) | |
260 | return 0; | |
261 | ||
262 | if (family->netnsok) { | |
263 | struct net *net; | |
264 | ||
265 | netlink_table_grab(); | |
266 | rcu_read_lock(); | |
267 | for_each_net_rcu(net) { | |
268 | err = __netlink_change_ngroups(net->genl_sock, | |
269 | mc_groups_longs * BITS_PER_LONG); | |
270 | if (err) { | |
271 | /* | |
272 | * No need to roll back, can only fail if | |
273 | * memory allocation fails and then the | |
274 | * number of _possible_ groups has been | |
275 | * increased on some sockets which is ok. | |
276 | */ | |
277 | break; | |
278 | } | |
279 | } | |
280 | rcu_read_unlock(); | |
281 | netlink_table_ungrab(); | |
282 | } else { | |
283 | err = netlink_change_ngroups(init_net.genl_sock, | |
284 | mc_groups_longs * BITS_PER_LONG); | |
285 | } | |
286 | ||
287 | if (groups_allocated && err) { | |
288 | for (i = 0; i < family->n_mcgrps; i++) | |
289 | clear_bit(family->mcgrp_offset + i, mc_groups); | |
290 | } | |
291 | ||
292 | return err; | |
293 | } | |
294 | ||
295 | static void genl_unregister_mc_groups(struct genl_family *family) | |
296 | { | |
297 | struct net *net; | |
298 | int i; | |
299 | ||
300 | netlink_table_grab(); | |
301 | rcu_read_lock(); | |
302 | for_each_net_rcu(net) { | |
303 | for (i = 0; i < family->n_mcgrps; i++) | |
304 | __netlink_clear_multicast_users( | |
305 | net->genl_sock, family->mcgrp_offset + i); | |
306 | } | |
307 | rcu_read_unlock(); | |
308 | netlink_table_ungrab(); | |
309 | ||
310 | for (i = 0; i < family->n_mcgrps; i++) { | |
311 | int grp_id = family->mcgrp_offset + i; | |
312 | ||
313 | if (grp_id != 1) | |
314 | clear_bit(grp_id, mc_groups); | |
315 | genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, family, | |
316 | &family->mcgrps[i], grp_id); | |
317 | } | |
318 | } | |
319 | ||
320 | static int genl_validate_ops(struct genl_family *family) | |
321 | { | |
322 | const struct genl_ops *ops = family->ops; | |
323 | unsigned int n_ops = family->n_ops; | |
324 | int i, j; | |
325 | ||
326 | if (WARN_ON(n_ops && !ops)) | |
327 | return -EINVAL; | |
328 | ||
329 | if (!n_ops) | |
330 | return 0; | |
331 | ||
332 | for (i = 0; i < n_ops; i++) { | |
333 | if (ops[i].dumpit == NULL && ops[i].doit == NULL) | |
334 | return -EINVAL; | |
335 | for (j = i + 1; j < n_ops; j++) | |
336 | if (ops[i].cmd == ops[j].cmd) | |
337 | return -EINVAL; | |
338 | } | |
339 | ||
340 | /* family is not registered yet, so no locking needed */ | |
341 | family->ops = ops; | |
342 | family->n_ops = n_ops; | |
343 | ||
344 | return 0; | |
345 | } | |
346 | ||
347 | /** | |
348 | * __genl_register_family - register a generic netlink family | |
349 | * @family: generic netlink family | |
350 | * | |
351 | * Registers the specified family after validating it first. Only one | |
352 | * family may be registered with the same family name or identifier. | |
353 | * The family id may equal GENL_ID_GENERATE causing an unique id to | |
354 | * be automatically generated and assigned. | |
355 | * | |
356 | * The family's ops array must already be assigned, you can use the | |
357 | * genl_register_family_with_ops() helper function. | |
358 | * | |
359 | * Return 0 on success or a negative error code. | |
360 | */ | |
361 | int __genl_register_family(struct genl_family *family) | |
362 | { | |
363 | int err = -EINVAL, i; | |
364 | ||
365 | if (family->id && family->id < GENL_MIN_ID) | |
366 | goto errout; | |
367 | ||
368 | if (family->id > GENL_MAX_ID) | |
369 | goto errout; | |
370 | ||
371 | err = genl_validate_ops(family); | |
372 | if (err) | |
373 | return err; | |
374 | ||
375 | genl_lock_all(); | |
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 && !family->parallel_ops) { | |
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 | err = genl_validate_assign_mc_groups(family); | |
407 | if (err) | |
408 | goto errout_locked; | |
409 | ||
410 | list_add_tail(&family->family_list, genl_family_chain(family->id)); | |
411 | genl_unlock_all(); | |
412 | ||
413 | /* send all events */ | |
414 | genl_ctrl_event(CTRL_CMD_NEWFAMILY, family, NULL, 0); | |
415 | for (i = 0; i < family->n_mcgrps; i++) | |
416 | genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, family, | |
417 | &family->mcgrps[i], family->mcgrp_offset + i); | |
418 | ||
419 | return 0; | |
420 | ||
421 | errout_locked: | |
422 | genl_unlock_all(); | |
423 | errout: | |
424 | return err; | |
425 | } | |
426 | EXPORT_SYMBOL(__genl_register_family); | |
427 | ||
428 | /** | |
429 | * genl_unregister_family - unregister generic netlink family | |
430 | * @family: generic netlink family | |
431 | * | |
432 | * Unregisters the specified family. | |
433 | * | |
434 | * Returns 0 on success or a negative error code. | |
435 | */ | |
436 | int genl_unregister_family(struct genl_family *family) | |
437 | { | |
438 | struct genl_family *rc; | |
439 | ||
440 | genl_lock_all(); | |
441 | ||
442 | genl_unregister_mc_groups(family); | |
443 | ||
444 | list_for_each_entry(rc, genl_family_chain(family->id), family_list) { | |
445 | if (family->id != rc->id || strcmp(rc->name, family->name)) | |
446 | continue; | |
447 | ||
448 | list_del(&rc->family_list); | |
449 | family->n_ops = 0; | |
450 | genl_unlock_all(); | |
451 | ||
452 | kfree(family->attrbuf); | |
453 | genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 0); | |
454 | return 0; | |
455 | } | |
456 | ||
457 | genl_unlock_all(); | |
458 | ||
459 | return -ENOENT; | |
460 | } | |
461 | EXPORT_SYMBOL(genl_unregister_family); | |
462 | ||
463 | /** | |
464 | * genlmsg_new_unicast - Allocate generic netlink message for unicast | |
465 | * @payload: size of the message payload | |
466 | * @info: information on destination | |
467 | * @flags: the type of memory to allocate | |
468 | * | |
469 | * Allocates a new sk_buff large enough to cover the specified payload | |
470 | * plus required Netlink headers. Will check receiving socket for | |
471 | * memory mapped i/o capability and use it if enabled. Will fall back | |
472 | * to non-mapped skb if message size exceeds the frame size of the ring. | |
473 | */ | |
474 | struct sk_buff *genlmsg_new_unicast(size_t payload, struct genl_info *info, | |
475 | gfp_t flags) | |
476 | { | |
477 | size_t len = nlmsg_total_size(genlmsg_total_size(payload)); | |
478 | ||
479 | return netlink_alloc_skb(info->dst_sk, len, info->snd_portid, flags); | |
480 | } | |
481 | EXPORT_SYMBOL_GPL(genlmsg_new_unicast); | |
482 | ||
483 | /** | |
484 | * genlmsg_put - Add generic netlink header to netlink message | |
485 | * @skb: socket buffer holding the message | |
486 | * @portid: netlink portid the message is addressed to | |
487 | * @seq: sequence number (usually the one of the sender) | |
488 | * @family: generic netlink family | |
489 | * @flags: netlink message flags | |
490 | * @cmd: generic netlink command | |
491 | * | |
492 | * Returns pointer to user specific header | |
493 | */ | |
494 | void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, | |
495 | struct genl_family *family, int flags, u8 cmd) | |
496 | { | |
497 | struct nlmsghdr *nlh; | |
498 | struct genlmsghdr *hdr; | |
499 | ||
500 | nlh = nlmsg_put(skb, portid, seq, family->id, GENL_HDRLEN + | |
501 | family->hdrsize, flags); | |
502 | if (nlh == NULL) | |
503 | return NULL; | |
504 | ||
505 | hdr = nlmsg_data(nlh); | |
506 | hdr->cmd = cmd; | |
507 | hdr->version = family->version; | |
508 | hdr->reserved = 0; | |
509 | ||
510 | return (char *) hdr + GENL_HDRLEN; | |
511 | } | |
512 | EXPORT_SYMBOL(genlmsg_put); | |
513 | ||
514 | static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb) | |
515 | { | |
516 | /* our ops are always const - netlink API doesn't propagate that */ | |
517 | const struct genl_ops *ops = cb->data; | |
518 | int rc; | |
519 | ||
520 | genl_lock(); | |
521 | rc = ops->dumpit(skb, cb); | |
522 | genl_unlock(); | |
523 | return rc; | |
524 | } | |
525 | ||
526 | static int genl_lock_done(struct netlink_callback *cb) | |
527 | { | |
528 | /* our ops are always const - netlink API doesn't propagate that */ | |
529 | const struct genl_ops *ops = cb->data; | |
530 | int rc = 0; | |
531 | ||
532 | if (ops->done) { | |
533 | genl_lock(); | |
534 | rc = ops->done(cb); | |
535 | genl_unlock(); | |
536 | } | |
537 | return rc; | |
538 | } | |
539 | ||
540 | static int genl_family_rcv_msg(struct genl_family *family, | |
541 | struct sk_buff *skb, | |
542 | struct nlmsghdr *nlh) | |
543 | { | |
544 | const struct genl_ops *ops; | |
545 | struct net *net = sock_net(skb->sk); | |
546 | struct genl_info info; | |
547 | struct genlmsghdr *hdr = nlmsg_data(nlh); | |
548 | struct nlattr **attrbuf; | |
549 | int hdrlen, err; | |
550 | ||
551 | /* this family doesn't exist in this netns */ | |
552 | if (!family->netnsok && !net_eq(net, &init_net)) | |
553 | return -ENOENT; | |
554 | ||
555 | hdrlen = GENL_HDRLEN + family->hdrsize; | |
556 | if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen)) | |
557 | return -EINVAL; | |
558 | ||
559 | ops = genl_get_cmd(hdr->cmd, family); | |
560 | if (ops == NULL) | |
561 | return -EOPNOTSUPP; | |
562 | ||
563 | if ((ops->flags & GENL_ADMIN_PERM) && | |
564 | !capable(CAP_NET_ADMIN)) | |
565 | return -EPERM; | |
566 | ||
567 | if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP) { | |
568 | int rc; | |
569 | ||
570 | if (ops->dumpit == NULL) | |
571 | return -EOPNOTSUPP; | |
572 | ||
573 | if (!family->parallel_ops) { | |
574 | struct netlink_dump_control c = { | |
575 | .module = family->module, | |
576 | /* we have const, but the netlink API doesn't */ | |
577 | .data = (void *)ops, | |
578 | .dump = genl_lock_dumpit, | |
579 | .done = genl_lock_done, | |
580 | }; | |
581 | ||
582 | genl_unlock(); | |
583 | rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c); | |
584 | genl_lock(); | |
585 | ||
586 | } else { | |
587 | struct netlink_dump_control c = { | |
588 | .module = family->module, | |
589 | .dump = ops->dumpit, | |
590 | .done = ops->done, | |
591 | }; | |
592 | ||
593 | rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c); | |
594 | } | |
595 | ||
596 | return rc; | |
597 | } | |
598 | ||
599 | if (ops->doit == NULL) | |
600 | return -EOPNOTSUPP; | |
601 | ||
602 | if (family->maxattr && family->parallel_ops) { | |
603 | attrbuf = kmalloc((family->maxattr+1) * | |
604 | sizeof(struct nlattr *), GFP_KERNEL); | |
605 | if (attrbuf == NULL) | |
606 | return -ENOMEM; | |
607 | } else | |
608 | attrbuf = family->attrbuf; | |
609 | ||
610 | if (attrbuf) { | |
611 | err = nlmsg_parse(nlh, hdrlen, attrbuf, family->maxattr, | |
612 | ops->policy); | |
613 | if (err < 0) | |
614 | goto out; | |
615 | } | |
616 | ||
617 | info.snd_seq = nlh->nlmsg_seq; | |
618 | info.snd_portid = NETLINK_CB(skb).portid; | |
619 | info.nlhdr = nlh; | |
620 | info.genlhdr = nlmsg_data(nlh); | |
621 | info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN; | |
622 | info.attrs = attrbuf; | |
623 | info.dst_sk = skb->sk; | |
624 | genl_info_net_set(&info, net); | |
625 | memset(&info.user_ptr, 0, sizeof(info.user_ptr)); | |
626 | ||
627 | if (family->pre_doit) { | |
628 | err = family->pre_doit(ops, skb, &info); | |
629 | if (err) | |
630 | goto out; | |
631 | } | |
632 | ||
633 | err = ops->doit(skb, &info); | |
634 | ||
635 | if (family->post_doit) | |
636 | family->post_doit(ops, skb, &info); | |
637 | ||
638 | out: | |
639 | if (family->parallel_ops) | |
640 | kfree(attrbuf); | |
641 | ||
642 | return err; | |
643 | } | |
644 | ||
645 | static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh) | |
646 | { | |
647 | struct genl_family *family; | |
648 | int err; | |
649 | ||
650 | family = genl_family_find_byid(nlh->nlmsg_type); | |
651 | if (family == NULL) | |
652 | return -ENOENT; | |
653 | ||
654 | if (!family->parallel_ops) | |
655 | genl_lock(); | |
656 | ||
657 | err = genl_family_rcv_msg(family, skb, nlh); | |
658 | ||
659 | if (!family->parallel_ops) | |
660 | genl_unlock(); | |
661 | ||
662 | return err; | |
663 | } | |
664 | ||
665 | static void genl_rcv(struct sk_buff *skb) | |
666 | { | |
667 | down_read(&cb_lock); | |
668 | netlink_rcv_skb(skb, &genl_rcv_msg); | |
669 | up_read(&cb_lock); | |
670 | } | |
671 | ||
672 | /************************************************************************** | |
673 | * Controller | |
674 | **************************************************************************/ | |
675 | ||
676 | static struct genl_family genl_ctrl = { | |
677 | .id = GENL_ID_CTRL, | |
678 | .name = "nlctrl", | |
679 | .version = 0x2, | |
680 | .maxattr = CTRL_ATTR_MAX, | |
681 | .netnsok = true, | |
682 | }; | |
683 | ||
684 | static int ctrl_fill_info(struct genl_family *family, u32 portid, u32 seq, | |
685 | u32 flags, struct sk_buff *skb, u8 cmd) | |
686 | { | |
687 | void *hdr; | |
688 | ||
689 | hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd); | |
690 | if (hdr == NULL) | |
691 | return -1; | |
692 | ||
693 | if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) || | |
694 | nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) || | |
695 | nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) || | |
696 | nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) || | |
697 | nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr)) | |
698 | goto nla_put_failure; | |
699 | ||
700 | if (family->n_ops) { | |
701 | struct nlattr *nla_ops; | |
702 | int i; | |
703 | ||
704 | nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS); | |
705 | if (nla_ops == NULL) | |
706 | goto nla_put_failure; | |
707 | ||
708 | for (i = 0; i < family->n_ops; i++) { | |
709 | struct nlattr *nest; | |
710 | const struct genl_ops *ops = &family->ops[i]; | |
711 | u32 op_flags = ops->flags; | |
712 | ||
713 | if (ops->dumpit) | |
714 | op_flags |= GENL_CMD_CAP_DUMP; | |
715 | if (ops->doit) | |
716 | op_flags |= GENL_CMD_CAP_DO; | |
717 | if (ops->policy) | |
718 | op_flags |= GENL_CMD_CAP_HASPOL; | |
719 | ||
720 | nest = nla_nest_start(skb, i + 1); | |
721 | if (nest == NULL) | |
722 | goto nla_put_failure; | |
723 | ||
724 | if (nla_put_u32(skb, CTRL_ATTR_OP_ID, ops->cmd) || | |
725 | nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, op_flags)) | |
726 | goto nla_put_failure; | |
727 | ||
728 | nla_nest_end(skb, nest); | |
729 | } | |
730 | ||
731 | nla_nest_end(skb, nla_ops); | |
732 | } | |
733 | ||
734 | if (family->n_mcgrps) { | |
735 | struct nlattr *nla_grps; | |
736 | int i; | |
737 | ||
738 | nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS); | |
739 | if (nla_grps == NULL) | |
740 | goto nla_put_failure; | |
741 | ||
742 | for (i = 0; i < family->n_mcgrps; i++) { | |
743 | struct nlattr *nest; | |
744 | const struct genl_multicast_group *grp; | |
745 | ||
746 | grp = &family->mcgrps[i]; | |
747 | ||
748 | nest = nla_nest_start(skb, i + 1); | |
749 | if (nest == NULL) | |
750 | goto nla_put_failure; | |
751 | ||
752 | if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, | |
753 | family->mcgrp_offset + i) || | |
754 | nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME, | |
755 | grp->name)) | |
756 | goto nla_put_failure; | |
757 | ||
758 | nla_nest_end(skb, nest); | |
759 | } | |
760 | nla_nest_end(skb, nla_grps); | |
761 | } | |
762 | ||
763 | return genlmsg_end(skb, hdr); | |
764 | ||
765 | nla_put_failure: | |
766 | genlmsg_cancel(skb, hdr); | |
767 | return -EMSGSIZE; | |
768 | } | |
769 | ||
770 | static int ctrl_fill_mcgrp_info(struct genl_family *family, | |
771 | const struct genl_multicast_group *grp, | |
772 | int grp_id, u32 portid, u32 seq, u32 flags, | |
773 | struct sk_buff *skb, u8 cmd) | |
774 | { | |
775 | void *hdr; | |
776 | struct nlattr *nla_grps; | |
777 | struct nlattr *nest; | |
778 | ||
779 | hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd); | |
780 | if (hdr == NULL) | |
781 | return -1; | |
782 | ||
783 | if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) || | |
784 | nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id)) | |
785 | goto nla_put_failure; | |
786 | ||
787 | nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS); | |
788 | if (nla_grps == NULL) | |
789 | goto nla_put_failure; | |
790 | ||
791 | nest = nla_nest_start(skb, 1); | |
792 | if (nest == NULL) | |
793 | goto nla_put_failure; | |
794 | ||
795 | if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp_id) || | |
796 | nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME, | |
797 | grp->name)) | |
798 | goto nla_put_failure; | |
799 | ||
800 | nla_nest_end(skb, nest); | |
801 | nla_nest_end(skb, nla_grps); | |
802 | ||
803 | return genlmsg_end(skb, hdr); | |
804 | ||
805 | nla_put_failure: | |
806 | genlmsg_cancel(skb, hdr); | |
807 | return -EMSGSIZE; | |
808 | } | |
809 | ||
810 | static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb) | |
811 | { | |
812 | ||
813 | int i, n = 0; | |
814 | struct genl_family *rt; | |
815 | struct net *net = sock_net(skb->sk); | |
816 | int chains_to_skip = cb->args[0]; | |
817 | int fams_to_skip = cb->args[1]; | |
818 | ||
819 | for (i = chains_to_skip; i < GENL_FAM_TAB_SIZE; i++) { | |
820 | n = 0; | |
821 | list_for_each_entry(rt, genl_family_chain(i), family_list) { | |
822 | if (!rt->netnsok && !net_eq(net, &init_net)) | |
823 | continue; | |
824 | if (++n < fams_to_skip) | |
825 | continue; | |
826 | if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid, | |
827 | cb->nlh->nlmsg_seq, NLM_F_MULTI, | |
828 | skb, CTRL_CMD_NEWFAMILY) < 0) | |
829 | goto errout; | |
830 | } | |
831 | ||
832 | fams_to_skip = 0; | |
833 | } | |
834 | ||
835 | errout: | |
836 | cb->args[0] = i; | |
837 | cb->args[1] = n; | |
838 | ||
839 | return skb->len; | |
840 | } | |
841 | ||
842 | static struct sk_buff *ctrl_build_family_msg(struct genl_family *family, | |
843 | u32 portid, int seq, u8 cmd) | |
844 | { | |
845 | struct sk_buff *skb; | |
846 | int err; | |
847 | ||
848 | skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); | |
849 | if (skb == NULL) | |
850 | return ERR_PTR(-ENOBUFS); | |
851 | ||
852 | err = ctrl_fill_info(family, portid, seq, 0, skb, cmd); | |
853 | if (err < 0) { | |
854 | nlmsg_free(skb); | |
855 | return ERR_PTR(err); | |
856 | } | |
857 | ||
858 | return skb; | |
859 | } | |
860 | ||
861 | static struct sk_buff * | |
862 | ctrl_build_mcgrp_msg(struct genl_family *family, | |
863 | const struct genl_multicast_group *grp, | |
864 | int grp_id, u32 portid, int seq, u8 cmd) | |
865 | { | |
866 | struct sk_buff *skb; | |
867 | int err; | |
868 | ||
869 | skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); | |
870 | if (skb == NULL) | |
871 | return ERR_PTR(-ENOBUFS); | |
872 | ||
873 | err = ctrl_fill_mcgrp_info(family, grp, grp_id, portid, | |
874 | seq, 0, skb, cmd); | |
875 | if (err < 0) { | |
876 | nlmsg_free(skb); | |
877 | return ERR_PTR(err); | |
878 | } | |
879 | ||
880 | return skb; | |
881 | } | |
882 | ||
883 | static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = { | |
884 | [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 }, | |
885 | [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING, | |
886 | .len = GENL_NAMSIZ - 1 }, | |
887 | }; | |
888 | ||
889 | static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info) | |
890 | { | |
891 | struct sk_buff *msg; | |
892 | struct genl_family *res = NULL; | |
893 | int err = -EINVAL; | |
894 | ||
895 | if (info->attrs[CTRL_ATTR_FAMILY_ID]) { | |
896 | u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]); | |
897 | res = genl_family_find_byid(id); | |
898 | err = -ENOENT; | |
899 | } | |
900 | ||
901 | if (info->attrs[CTRL_ATTR_FAMILY_NAME]) { | |
902 | char *name; | |
903 | ||
904 | name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]); | |
905 | res = genl_family_find_byname(name); | |
906 | #ifdef CONFIG_MODULES | |
907 | if (res == NULL) { | |
908 | genl_unlock(); | |
909 | up_read(&cb_lock); | |
910 | request_module("net-pf-%d-proto-%d-family-%s", | |
911 | PF_NETLINK, NETLINK_GENERIC, name); | |
912 | down_read(&cb_lock); | |
913 | genl_lock(); | |
914 | res = genl_family_find_byname(name); | |
915 | } | |
916 | #endif | |
917 | err = -ENOENT; | |
918 | } | |
919 | ||
920 | if (res == NULL) | |
921 | return err; | |
922 | ||
923 | if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) { | |
924 | /* family doesn't exist here */ | |
925 | return -ENOENT; | |
926 | } | |
927 | ||
928 | msg = ctrl_build_family_msg(res, info->snd_portid, info->snd_seq, | |
929 | CTRL_CMD_NEWFAMILY); | |
930 | if (IS_ERR(msg)) | |
931 | return PTR_ERR(msg); | |
932 | ||
933 | return genlmsg_reply(msg, info); | |
934 | } | |
935 | ||
936 | static int genl_ctrl_event(int event, struct genl_family *family, | |
937 | const struct genl_multicast_group *grp, | |
938 | int grp_id) | |
939 | { | |
940 | struct sk_buff *msg; | |
941 | ||
942 | /* genl is still initialising */ | |
943 | if (!init_net.genl_sock) | |
944 | return 0; | |
945 | ||
946 | switch (event) { | |
947 | case CTRL_CMD_NEWFAMILY: | |
948 | case CTRL_CMD_DELFAMILY: | |
949 | WARN_ON(grp); | |
950 | msg = ctrl_build_family_msg(family, 0, 0, event); | |
951 | break; | |
952 | case CTRL_CMD_NEWMCAST_GRP: | |
953 | case CTRL_CMD_DELMCAST_GRP: | |
954 | BUG_ON(!grp); | |
955 | msg = ctrl_build_mcgrp_msg(family, grp, grp_id, 0, 0, event); | |
956 | break; | |
957 | default: | |
958 | return -EINVAL; | |
959 | } | |
960 | ||
961 | if (IS_ERR(msg)) | |
962 | return PTR_ERR(msg); | |
963 | ||
964 | if (!family->netnsok) { | |
965 | genlmsg_multicast_netns(&genl_ctrl, &init_net, msg, 0, | |
966 | 0, GFP_KERNEL); | |
967 | } else { | |
968 | rcu_read_lock(); | |
969 | genlmsg_multicast_allns(&genl_ctrl, msg, 0, | |
970 | 0, GFP_ATOMIC); | |
971 | rcu_read_unlock(); | |
972 | } | |
973 | ||
974 | return 0; | |
975 | } | |
976 | ||
977 | static struct genl_ops genl_ctrl_ops[] = { | |
978 | { | |
979 | .cmd = CTRL_CMD_GETFAMILY, | |
980 | .doit = ctrl_getfamily, | |
981 | .dumpit = ctrl_dumpfamily, | |
982 | .policy = ctrl_policy, | |
983 | }, | |
984 | }; | |
985 | ||
986 | static struct genl_multicast_group genl_ctrl_groups[] = { | |
987 | { .name = "notify", }, | |
988 | }; | |
989 | ||
990 | static int __net_init genl_pernet_init(struct net *net) | |
991 | { | |
992 | struct netlink_kernel_cfg cfg = { | |
993 | .input = genl_rcv, | |
994 | .flags = NL_CFG_F_NONROOT_RECV, | |
995 | }; | |
996 | ||
997 | /* we'll bump the group number right afterwards */ | |
998 | net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg); | |
999 | ||
1000 | if (!net->genl_sock && net_eq(net, &init_net)) | |
1001 | panic("GENL: Cannot initialize generic netlink\n"); | |
1002 | ||
1003 | if (!net->genl_sock) | |
1004 | return -ENOMEM; | |
1005 | ||
1006 | return 0; | |
1007 | } | |
1008 | ||
1009 | static void __net_exit genl_pernet_exit(struct net *net) | |
1010 | { | |
1011 | netlink_kernel_release(net->genl_sock); | |
1012 | net->genl_sock = NULL; | |
1013 | } | |
1014 | ||
1015 | static struct pernet_operations genl_pernet_ops = { | |
1016 | .init = genl_pernet_init, | |
1017 | .exit = genl_pernet_exit, | |
1018 | }; | |
1019 | ||
1020 | static int __init genl_init(void) | |
1021 | { | |
1022 | int i, err; | |
1023 | ||
1024 | for (i = 0; i < GENL_FAM_TAB_SIZE; i++) | |
1025 | INIT_LIST_HEAD(&family_ht[i]); | |
1026 | ||
1027 | err = genl_register_family_with_ops_groups(&genl_ctrl, genl_ctrl_ops, | |
1028 | genl_ctrl_groups); | |
1029 | if (err < 0) | |
1030 | goto problem; | |
1031 | ||
1032 | err = register_pernet_subsys(&genl_pernet_ops); | |
1033 | if (err) | |
1034 | goto problem; | |
1035 | ||
1036 | return 0; | |
1037 | ||
1038 | problem: | |
1039 | panic("GENL: Cannot register controller: %d\n", err); | |
1040 | } | |
1041 | ||
1042 | subsys_initcall(genl_init); | |
1043 | ||
1044 | static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group, | |
1045 | gfp_t flags) | |
1046 | { | |
1047 | struct sk_buff *tmp; | |
1048 | struct net *net, *prev = NULL; | |
1049 | int err; | |
1050 | ||
1051 | for_each_net_rcu(net) { | |
1052 | if (prev) { | |
1053 | tmp = skb_clone(skb, flags); | |
1054 | if (!tmp) { | |
1055 | err = -ENOMEM; | |
1056 | goto error; | |
1057 | } | |
1058 | err = nlmsg_multicast(prev->genl_sock, tmp, | |
1059 | portid, group, flags); | |
1060 | if (err) | |
1061 | goto error; | |
1062 | } | |
1063 | ||
1064 | prev = net; | |
1065 | } | |
1066 | ||
1067 | return nlmsg_multicast(prev->genl_sock, skb, portid, group, flags); | |
1068 | error: | |
1069 | kfree_skb(skb); | |
1070 | return err; | |
1071 | } | |
1072 | ||
1073 | int genlmsg_multicast_allns(struct genl_family *family, struct sk_buff *skb, | |
1074 | u32 portid, unsigned int group, gfp_t flags) | |
1075 | { | |
1076 | if (WARN_ON_ONCE(group >= family->n_mcgrps)) | |
1077 | return -EINVAL; | |
1078 | group = family->mcgrp_offset + group; | |
1079 | return genlmsg_mcast(skb, portid, group, flags); | |
1080 | } | |
1081 | EXPORT_SYMBOL(genlmsg_multicast_allns); | |
1082 | ||
1083 | void genl_notify(struct genl_family *family, | |
1084 | struct sk_buff *skb, struct net *net, u32 portid, u32 group, | |
1085 | struct nlmsghdr *nlh, gfp_t flags) | |
1086 | { | |
1087 | struct sock *sk = net->genl_sock; | |
1088 | int report = 0; | |
1089 | ||
1090 | if (nlh) | |
1091 | report = nlmsg_report(nlh); | |
1092 | ||
1093 | if (WARN_ON_ONCE(group >= family->n_mcgrps)) | |
1094 | return; | |
1095 | group = family->mcgrp_offset + group; | |
1096 | nlmsg_notify(sk, skb, portid, group, report, flags); | |
1097 | } | |
1098 | EXPORT_SYMBOL(genl_notify); |