Commit | Line | Data |
---|---|---|
482a8524 TG |
1 | /* |
2 | * NETLINK Generic Netlink Family | |
3 | * | |
4 | * Authors: Jamal Hadi Salim | |
5 | * Thomas Graf <tgraf@suug.ch> | |
6 | */ | |
7 | ||
482a8524 TG |
8 | #include <linux/module.h> |
9 | #include <linux/kernel.h> | |
10 | #include <linux/errno.h> | |
11 | #include <linux/types.h> | |
12 | #include <linux/socket.h> | |
13 | #include <linux/string.h> | |
14 | #include <linux/skbuff.h> | |
14cc3e2b | 15 | #include <linux/mutex.h> |
482a8524 TG |
16 | #include <net/sock.h> |
17 | #include <net/genetlink.h> | |
18 | ||
19 | struct sock *genl_sock = NULL; | |
20 | ||
14cc3e2b | 21 | static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */ |
482a8524 TG |
22 | |
23 | static void genl_lock(void) | |
24 | { | |
14cc3e2b | 25 | mutex_lock(&genl_mutex); |
482a8524 TG |
26 | } |
27 | ||
28 | static int genl_trylock(void) | |
29 | { | |
14cc3e2b | 30 | return !mutex_trylock(&genl_mutex); |
482a8524 TG |
31 | } |
32 | ||
33 | static void genl_unlock(void) | |
34 | { | |
14cc3e2b | 35 | mutex_unlock(&genl_mutex); |
482a8524 TG |
36 | |
37 | if (genl_sock && genl_sock->sk_receive_queue.qlen) | |
38 | genl_sock->sk_data_ready(genl_sock, 0); | |
39 | } | |
40 | ||
41 | #define GENL_FAM_TAB_SIZE 16 | |
42 | #define GENL_FAM_TAB_MASK (GENL_FAM_TAB_SIZE - 1) | |
43 | ||
44 | static struct list_head family_ht[GENL_FAM_TAB_SIZE]; | |
45 | ||
46 | static int genl_ctrl_event(int event, void *data); | |
47 | ||
48 | static inline unsigned int genl_family_hash(unsigned int id) | |
49 | { | |
50 | return id & GENL_FAM_TAB_MASK; | |
51 | } | |
52 | ||
53 | static inline struct list_head *genl_family_chain(unsigned int id) | |
54 | { | |
55 | return &family_ht[genl_family_hash(id)]; | |
56 | } | |
57 | ||
58 | static struct genl_family *genl_family_find_byid(unsigned int id) | |
59 | { | |
60 | struct genl_family *f; | |
61 | ||
62 | list_for_each_entry(f, genl_family_chain(id), family_list) | |
63 | if (f->id == id) | |
64 | return f; | |
65 | ||
66 | return NULL; | |
67 | } | |
68 | ||
69 | static struct genl_family *genl_family_find_byname(char *name) | |
70 | { | |
71 | struct genl_family *f; | |
72 | int i; | |
73 | ||
74 | for (i = 0; i < GENL_FAM_TAB_SIZE; i++) | |
75 | list_for_each_entry(f, genl_family_chain(i), family_list) | |
76 | if (strcmp(f->name, name) == 0) | |
77 | return f; | |
78 | ||
79 | return NULL; | |
80 | } | |
81 | ||
82 | static struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family) | |
83 | { | |
84 | struct genl_ops *ops; | |
85 | ||
86 | list_for_each_entry(ops, &family->ops_list, ops_list) | |
87 | if (ops->cmd == cmd) | |
88 | return ops; | |
89 | ||
90 | return NULL; | |
91 | } | |
92 | ||
93 | /* Of course we are going to have problems once we hit | |
94 | * 2^16 alive types, but that can only happen by year 2K | |
95 | */ | |
96 | static inline u16 genl_generate_id(void) | |
97 | { | |
98 | static u16 id_gen_idx; | |
99 | int overflowed = 0; | |
100 | ||
101 | do { | |
102 | if (id_gen_idx == 0) | |
103 | id_gen_idx = GENL_MIN_ID; | |
104 | ||
105 | if (++id_gen_idx > GENL_MAX_ID) { | |
106 | if (!overflowed) { | |
107 | overflowed = 1; | |
108 | id_gen_idx = 0; | |
109 | continue; | |
110 | } else | |
111 | return 0; | |
112 | } | |
113 | ||
114 | } while (genl_family_find_byid(id_gen_idx)); | |
115 | ||
116 | return id_gen_idx; | |
117 | } | |
118 | ||
119 | /** | |
120 | * genl_register_ops - register generic netlink operations | |
121 | * @family: generic netlink family | |
122 | * @ops: operations to be registered | |
123 | * | |
124 | * Registers the specified operations and assigns them to the specified | |
125 | * family. Either a doit or dumpit callback must be specified or the | |
126 | * operation will fail. Only one operation structure per command | |
127 | * identifier may be registered. | |
128 | * | |
129 | * See include/net/genetlink.h for more documenation on the operations | |
130 | * structure. | |
131 | * | |
132 | * Returns 0 on success or a negative error code. | |
133 | */ | |
134 | int genl_register_ops(struct genl_family *family, struct genl_ops *ops) | |
135 | { | |
136 | int err = -EINVAL; | |
137 | ||
138 | if (ops->dumpit == NULL && ops->doit == NULL) | |
139 | goto errout; | |
140 | ||
141 | if (genl_get_cmd(ops->cmd, family)) { | |
142 | err = -EEXIST; | |
143 | goto errout; | |
144 | } | |
145 | ||
334c29a6 | 146 | if (ops->dumpit) |
334c29a6 | 147 | ops->flags |= GENL_CMD_CAP_DUMP; |
48d4ed7a JHS |
148 | if (ops->doit) |
149 | ops->flags |= GENL_CMD_CAP_DO; | |
334c29a6 JHS |
150 | if (ops->policy) |
151 | ops->flags |= GENL_CMD_CAP_HASPOL; | |
152 | ||
482a8524 TG |
153 | genl_lock(); |
154 | list_add_tail(&ops->ops_list, &family->ops_list); | |
155 | genl_unlock(); | |
156 | ||
157 | genl_ctrl_event(CTRL_CMD_NEWOPS, ops); | |
158 | err = 0; | |
159 | errout: | |
160 | return err; | |
161 | } | |
162 | ||
163 | /** | |
164 | * genl_unregister_ops - unregister generic netlink operations | |
165 | * @family: generic netlink family | |
166 | * @ops: operations to be unregistered | |
167 | * | |
168 | * Unregisters the specified operations and unassigns them from the | |
169 | * specified family. The operation blocks until the current message | |
170 | * processing has finished and doesn't start again until the | |
171 | * unregister process has finished. | |
172 | * | |
173 | * Note: It is not necessary to unregister all operations before | |
174 | * unregistering the family, unregistering the family will cause | |
175 | * all assigned operations to be unregistered automatically. | |
176 | * | |
177 | * Returns 0 on success or a negative error code. | |
178 | */ | |
179 | int genl_unregister_ops(struct genl_family *family, struct genl_ops *ops) | |
180 | { | |
181 | struct genl_ops *rc; | |
182 | ||
183 | genl_lock(); | |
184 | list_for_each_entry(rc, &family->ops_list, ops_list) { | |
185 | if (rc == ops) { | |
186 | list_del(&ops->ops_list); | |
187 | genl_unlock(); | |
188 | genl_ctrl_event(CTRL_CMD_DELOPS, ops); | |
189 | return 0; | |
190 | } | |
191 | } | |
192 | genl_unlock(); | |
193 | ||
194 | return -ENOENT; | |
195 | } | |
196 | ||
197 | /** | |
198 | * genl_register_family - register a generic netlink family | |
199 | * @family: generic netlink family | |
200 | * | |
201 | * Registers the specified family after validating it first. Only one | |
202 | * family may be registered with the same family name or identifier. | |
203 | * The family id may equal GENL_ID_GENERATE causing an unique id to | |
204 | * be automatically generated and assigned. | |
205 | * | |
206 | * Return 0 on success or a negative error code. | |
207 | */ | |
208 | int genl_register_family(struct genl_family *family) | |
209 | { | |
210 | int err = -EINVAL; | |
211 | ||
212 | if (family->id && family->id < GENL_MIN_ID) | |
213 | goto errout; | |
214 | ||
215 | if (family->id > GENL_MAX_ID) | |
216 | goto errout; | |
217 | ||
218 | INIT_LIST_HEAD(&family->ops_list); | |
219 | ||
220 | genl_lock(); | |
221 | ||
222 | if (genl_family_find_byname(family->name)) { | |
223 | err = -EEXIST; | |
224 | goto errout_locked; | |
225 | } | |
226 | ||
227 | if (genl_family_find_byid(family->id)) { | |
228 | err = -EEXIST; | |
229 | goto errout_locked; | |
230 | } | |
231 | ||
482a8524 TG |
232 | if (family->id == GENL_ID_GENERATE) { |
233 | u16 newid = genl_generate_id(); | |
234 | ||
235 | if (!newid) { | |
236 | err = -ENOMEM; | |
237 | goto errout_locked; | |
238 | } | |
239 | ||
240 | family->id = newid; | |
241 | } | |
242 | ||
243 | if (family->maxattr) { | |
244 | family->attrbuf = kmalloc((family->maxattr+1) * | |
245 | sizeof(struct nlattr *), GFP_KERNEL); | |
246 | if (family->attrbuf == NULL) { | |
247 | err = -ENOMEM; | |
e200bd80 | 248 | goto errout_locked; |
482a8524 TG |
249 | } |
250 | } else | |
251 | family->attrbuf = NULL; | |
252 | ||
253 | list_add_tail(&family->family_list, genl_family_chain(family->id)); | |
254 | genl_unlock(); | |
255 | ||
256 | genl_ctrl_event(CTRL_CMD_NEWFAMILY, family); | |
257 | ||
258 | return 0; | |
259 | ||
260 | errout_locked: | |
261 | genl_unlock(); | |
262 | errout: | |
263 | return err; | |
264 | } | |
265 | ||
266 | /** | |
267 | * genl_unregister_family - unregister generic netlink family | |
268 | * @family: generic netlink family | |
269 | * | |
270 | * Unregisters the specified family. | |
271 | * | |
272 | * Returns 0 on success or a negative error code. | |
273 | */ | |
274 | int genl_unregister_family(struct genl_family *family) | |
275 | { | |
276 | struct genl_family *rc; | |
277 | ||
278 | genl_lock(); | |
279 | ||
280 | list_for_each_entry(rc, genl_family_chain(family->id), family_list) { | |
281 | if (family->id != rc->id || strcmp(rc->name, family->name)) | |
282 | continue; | |
283 | ||
284 | list_del(&rc->family_list); | |
285 | INIT_LIST_HEAD(&family->ops_list); | |
286 | genl_unlock(); | |
287 | ||
482a8524 TG |
288 | kfree(family->attrbuf); |
289 | genl_ctrl_event(CTRL_CMD_DELFAMILY, family); | |
290 | return 0; | |
291 | } | |
292 | ||
293 | genl_unlock(); | |
294 | ||
295 | return -ENOENT; | |
296 | } | |
297 | ||
1d00a4eb | 298 | static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh) |
482a8524 TG |
299 | { |
300 | struct genl_ops *ops; | |
301 | struct genl_family *family; | |
302 | struct genl_info info; | |
303 | struct genlmsghdr *hdr = nlmsg_data(nlh); | |
1d00a4eb | 304 | int hdrlen, err; |
482a8524 | 305 | |
746fac4d | 306 | family = genl_family_find_byid(nlh->nlmsg_type); |
1d00a4eb TG |
307 | if (family == NULL) |
308 | return -ENOENT; | |
482a8524 TG |
309 | |
310 | hdrlen = GENL_HDRLEN + family->hdrsize; | |
311 | if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen)) | |
1d00a4eb | 312 | return -EINVAL; |
482a8524 TG |
313 | |
314 | ops = genl_get_cmd(hdr->cmd, family); | |
1d00a4eb TG |
315 | if (ops == NULL) |
316 | return -EOPNOTSUPP; | |
482a8524 | 317 | |
1d00a4eb TG |
318 | if ((ops->flags & GENL_ADMIN_PERM) && |
319 | security_netlink_recv(skb, CAP_NET_ADMIN)) | |
320 | return -EPERM; | |
482a8524 TG |
321 | |
322 | if (nlh->nlmsg_flags & NLM_F_DUMP) { | |
1d00a4eb TG |
323 | if (ops->dumpit == NULL) |
324 | return -EOPNOTSUPP; | |
482a8524 | 325 | |
1d00a4eb TG |
326 | err = netlink_dump_start(genl_sock, skb, nlh, |
327 | ops->dumpit, ops->done); | |
482a8524 | 328 | if (err == 0) |
1d00a4eb TG |
329 | err = -EINTR; |
330 | return err; | |
482a8524 TG |
331 | } |
332 | ||
1d00a4eb TG |
333 | if (ops->doit == NULL) |
334 | return -EOPNOTSUPP; | |
482a8524 TG |
335 | |
336 | if (family->attrbuf) { | |
337 | err = nlmsg_parse(nlh, hdrlen, family->attrbuf, family->maxattr, | |
338 | ops->policy); | |
339 | if (err < 0) | |
1d00a4eb | 340 | return err; |
482a8524 TG |
341 | } |
342 | ||
343 | info.snd_seq = nlh->nlmsg_seq; | |
344 | info.snd_pid = NETLINK_CB(skb).pid; | |
345 | info.nlhdr = nlh; | |
346 | info.genlhdr = nlmsg_data(nlh); | |
347 | info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN; | |
348 | info.attrs = family->attrbuf; | |
349 | ||
1d00a4eb | 350 | return ops->doit(skb, &info); |
482a8524 TG |
351 | } |
352 | ||
353 | static void genl_rcv(struct sock *sk, int len) | |
354 | { | |
355 | unsigned int qlen = 0; | |
356 | ||
357 | do { | |
358 | if (genl_trylock()) | |
359 | return; | |
e200bd80 | 360 | netlink_run_queue(sk, &qlen, genl_rcv_msg); |
482a8524 TG |
361 | genl_unlock(); |
362 | } while (qlen && genl_sock && genl_sock->sk_receive_queue.qlen); | |
363 | } | |
364 | ||
365 | /************************************************************************** | |
366 | * Controller | |
367 | **************************************************************************/ | |
368 | ||
17c157c8 TG |
369 | static struct genl_family genl_ctrl = { |
370 | .id = GENL_ID_CTRL, | |
371 | .name = "nlctrl", | |
334c29a6 | 372 | .version = 0x2, |
17c157c8 TG |
373 | .maxattr = CTRL_ATTR_MAX, |
374 | }; | |
375 | ||
482a8524 TG |
376 | static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq, |
377 | u32 flags, struct sk_buff *skb, u8 cmd) | |
378 | { | |
379 | void *hdr; | |
380 | ||
17c157c8 | 381 | hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd); |
482a8524 TG |
382 | if (hdr == NULL) |
383 | return -1; | |
384 | ||
385 | NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, family->name); | |
386 | NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, family->id); | |
eb328111 TG |
387 | NLA_PUT_U32(skb, CTRL_ATTR_VERSION, family->version); |
388 | NLA_PUT_U32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize); | |
389 | NLA_PUT_U32(skb, CTRL_ATTR_MAXATTR, family->maxattr); | |
390 | ||
e94ef682 TG |
391 | if (!list_empty(&family->ops_list)) { |
392 | struct nlattr *nla_ops; | |
393 | struct genl_ops *ops; | |
394 | int idx = 1; | |
eb328111 | 395 | |
e94ef682 TG |
396 | nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS); |
397 | if (nla_ops == NULL) | |
eb328111 TG |
398 | goto nla_put_failure; |
399 | ||
e94ef682 TG |
400 | list_for_each_entry(ops, &family->ops_list, ops_list) { |
401 | struct nlattr *nest; | |
eb328111 | 402 | |
e94ef682 TG |
403 | nest = nla_nest_start(skb, idx++); |
404 | if (nest == NULL) | |
405 | goto nla_put_failure; | |
eb328111 | 406 | |
e94ef682 TG |
407 | NLA_PUT_U32(skb, CTRL_ATTR_OP_ID, ops->cmd); |
408 | NLA_PUT_U32(skb, CTRL_ATTR_OP_FLAGS, ops->flags); | |
eb328111 | 409 | |
e94ef682 TG |
410 | nla_nest_end(skb, nest); |
411 | } | |
412 | ||
413 | nla_nest_end(skb, nla_ops); | |
414 | } | |
482a8524 TG |
415 | |
416 | return genlmsg_end(skb, hdr); | |
417 | ||
418 | nla_put_failure: | |
419 | return genlmsg_cancel(skb, hdr); | |
420 | } | |
421 | ||
422 | static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb) | |
423 | { | |
424 | ||
425 | int i, n = 0; | |
426 | struct genl_family *rt; | |
427 | int chains_to_skip = cb->args[0]; | |
428 | int fams_to_skip = cb->args[1]; | |
429 | ||
eb328111 TG |
430 | if (chains_to_skip != 0) |
431 | genl_lock(); | |
432 | ||
482a8524 TG |
433 | for (i = 0; i < GENL_FAM_TAB_SIZE; i++) { |
434 | if (i < chains_to_skip) | |
435 | continue; | |
436 | n = 0; | |
437 | list_for_each_entry(rt, genl_family_chain(i), family_list) { | |
438 | if (++n < fams_to_skip) | |
439 | continue; | |
440 | if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).pid, | |
441 | cb->nlh->nlmsg_seq, NLM_F_MULTI, | |
442 | skb, CTRL_CMD_NEWFAMILY) < 0) | |
443 | goto errout; | |
444 | } | |
445 | ||
446 | fams_to_skip = 0; | |
447 | } | |
448 | ||
449 | errout: | |
eb328111 TG |
450 | if (chains_to_skip != 0) |
451 | genl_unlock(); | |
452 | ||
482a8524 TG |
453 | cb->args[0] = i; |
454 | cb->args[1] = n; | |
455 | ||
456 | return skb->len; | |
457 | } | |
458 | ||
459 | static struct sk_buff *ctrl_build_msg(struct genl_family *family, u32 pid, | |
b461d2f2 | 460 | int seq, u8 cmd) |
482a8524 TG |
461 | { |
462 | struct sk_buff *skb; | |
463 | int err; | |
464 | ||
339bf98f | 465 | skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); |
482a8524 TG |
466 | if (skb == NULL) |
467 | return ERR_PTR(-ENOBUFS); | |
468 | ||
469 | err = ctrl_fill_info(family, pid, seq, 0, skb, cmd); | |
470 | if (err < 0) { | |
471 | nlmsg_free(skb); | |
472 | return ERR_PTR(err); | |
473 | } | |
474 | ||
475 | return skb; | |
476 | } | |
477 | ||
478 | static struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] __read_mostly = { | |
479 | [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 }, | |
5176f91e TG |
480 | [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING, |
481 | .len = GENL_NAMSIZ - 1 }, | |
482a8524 TG |
482 | }; |
483 | ||
484 | static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info) | |
485 | { | |
486 | struct sk_buff *msg; | |
487 | struct genl_family *res = NULL; | |
488 | int err = -EINVAL; | |
489 | ||
490 | if (info->attrs[CTRL_ATTR_FAMILY_ID]) { | |
491 | u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]); | |
492 | res = genl_family_find_byid(id); | |
493 | } | |
494 | ||
495 | if (info->attrs[CTRL_ATTR_FAMILY_NAME]) { | |
5176f91e | 496 | char *name; |
482a8524 | 497 | |
5176f91e | 498 | name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]); |
482a8524 TG |
499 | res = genl_family_find_byname(name); |
500 | } | |
501 | ||
502 | if (res == NULL) { | |
503 | err = -ENOENT; | |
504 | goto errout; | |
505 | } | |
506 | ||
507 | msg = ctrl_build_msg(res, info->snd_pid, info->snd_seq, | |
508 | CTRL_CMD_NEWFAMILY); | |
509 | if (IS_ERR(msg)) { | |
510 | err = PTR_ERR(msg); | |
511 | goto errout; | |
512 | } | |
513 | ||
81878d27 | 514 | err = genlmsg_reply(msg, info); |
482a8524 TG |
515 | errout: |
516 | return err; | |
517 | } | |
518 | ||
519 | static int genl_ctrl_event(int event, void *data) | |
520 | { | |
521 | struct sk_buff *msg; | |
522 | ||
523 | if (genl_sock == NULL) | |
524 | return 0; | |
525 | ||
526 | switch (event) { | |
527 | case CTRL_CMD_NEWFAMILY: | |
528 | case CTRL_CMD_DELFAMILY: | |
529 | msg = ctrl_build_msg(data, 0, 0, event); | |
530 | if (IS_ERR(msg)) | |
531 | return PTR_ERR(msg); | |
532 | ||
d387f6ad | 533 | genlmsg_multicast(msg, 0, GENL_ID_CTRL, GFP_KERNEL); |
482a8524 TG |
534 | break; |
535 | } | |
536 | ||
537 | return 0; | |
538 | } | |
539 | ||
540 | static struct genl_ops genl_ctrl_ops = { | |
541 | .cmd = CTRL_CMD_GETFAMILY, | |
542 | .doit = ctrl_getfamily, | |
543 | .dumpit = ctrl_dumpfamily, | |
544 | .policy = ctrl_policy, | |
545 | }; | |
546 | ||
482a8524 TG |
547 | static int __init genl_init(void) |
548 | { | |
549 | int i, err; | |
550 | ||
551 | for (i = 0; i < GENL_FAM_TAB_SIZE; i++) | |
552 | INIT_LIST_HEAD(&family_ht[i]); | |
553 | ||
554 | err = genl_register_family(&genl_ctrl); | |
555 | if (err < 0) | |
556 | goto errout; | |
557 | ||
558 | err = genl_register_ops(&genl_ctrl, &genl_ctrl_ops); | |
559 | if (err < 0) | |
560 | goto errout_register; | |
561 | ||
562 | netlink_set_nonroot(NETLINK_GENERIC, NL_NONROOT_RECV); | |
563 | genl_sock = netlink_kernel_create(NETLINK_GENERIC, GENL_MAX_ID, | |
564 | genl_rcv, THIS_MODULE); | |
e200bd80 | 565 | if (genl_sock == NULL) |
482a8524 | 566 | panic("GENL: Cannot initialize generic netlink\n"); |
482a8524 TG |
567 | |
568 | return 0; | |
569 | ||
570 | errout_register: | |
571 | genl_unregister_family(&genl_ctrl); | |
572 | errout: | |
573 | panic("GENL: Cannot register controller: %d\n", err); | |
482a8524 TG |
574 | } |
575 | ||
576 | subsys_initcall(genl_init); | |
577 | ||
578 | EXPORT_SYMBOL(genl_sock); | |
579 | EXPORT_SYMBOL(genl_register_ops); | |
580 | EXPORT_SYMBOL(genl_unregister_ops); | |
581 | EXPORT_SYMBOL(genl_register_family); | |
582 | EXPORT_SYMBOL(genl_unregister_family); |