blob: b5df749cba8fe11746ed6f9bb5c363966233880c [file] [log] [blame]
Thomas Graf482a8522005-11-10 02:25:56 +01001/*
2 * NETLINK Generic Netlink Family
3 *
4 * Authors: Jamal Hadi Salim
5 * Thomas Graf <tgraf@suug.ch>
6 */
7
Thomas Graf482a8522005-11-10 02:25:56 +01008#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>
Ingo Molnar14cc3e22006-03-26 01:37:14 -080015#include <linux/mutex.h>
Thomas Graf482a8522005-11-10 02:25:56 +010016#include <net/sock.h>
17#include <net/genetlink.h>
18
19struct sock *genl_sock = NULL;
20
Ingo Molnar14cc3e22006-03-26 01:37:14 -080021static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */
Thomas Graf482a8522005-11-10 02:25:56 +010022
23static void genl_lock(void)
24{
Ingo Molnar14cc3e22006-03-26 01:37:14 -080025 mutex_lock(&genl_mutex);
Thomas Graf482a8522005-11-10 02:25:56 +010026}
27
28static int genl_trylock(void)
29{
Ingo Molnar14cc3e22006-03-26 01:37:14 -080030 return !mutex_trylock(&genl_mutex);
Thomas Graf482a8522005-11-10 02:25:56 +010031}
32
33static void genl_unlock(void)
34{
Ingo Molnar14cc3e22006-03-26 01:37:14 -080035 mutex_unlock(&genl_mutex);
Thomas Graf482a8522005-11-10 02:25:56 +010036
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
44static struct list_head family_ht[GENL_FAM_TAB_SIZE];
45
46static int genl_ctrl_event(int event, void *data);
47
48static inline unsigned int genl_family_hash(unsigned int id)
49{
50 return id & GENL_FAM_TAB_MASK;
51}
52
53static inline struct list_head *genl_family_chain(unsigned int id)
54{
55 return &family_ht[genl_family_hash(id)];
56}
57
58static 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
69static 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
82static 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*/
96static 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 */
134int 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
Jamal Hadi Salim334c29a2006-12-04 19:31:51 -0800146 if (ops->dumpit)
147 ops->flags |= GENL_CMD_CAP_DO;
148 if (ops->doit)
149 ops->flags |= GENL_CMD_CAP_DUMP;
150 if (ops->policy)
151 ops->flags |= GENL_CMD_CAP_HASPOL;
152
Thomas Graf482a8522005-11-10 02:25:56 +0100153 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;
159errout:
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 */
179int 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 */
208int 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
Thomas Graf482a8522005-11-10 02:25:56 +0100232 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;
Jamal Hadi Salime200bd82006-02-13 15:51:24 -0800248 goto errout_locked;
Thomas Graf482a8522005-11-10 02:25:56 +0100249 }
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
260errout_locked:
261 genl_unlock();
262errout:
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 */
274int 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
Thomas Graf482a8522005-11-10 02:25:56 +0100288 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
Jamal Hadi Salime200bd82006-02-13 15:51:24 -0800298static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
Thomas Graf482a8522005-11-10 02:25:56 +0100299 int *errp)
300{
301 struct genl_ops *ops;
302 struct genl_family *family;
303 struct genl_info info;
304 struct genlmsghdr *hdr = nlmsg_data(nlh);
305 int hdrlen, err = -EINVAL;
306
307 if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
308 goto ignore;
309
310 if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
311 goto ignore;
312
313 family = genl_family_find_byid(nlh->nlmsg_type);
314 if (family == NULL) {
315 err = -ENOENT;
316 goto errout;
317 }
318
319 hdrlen = GENL_HDRLEN + family->hdrsize;
320 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
321 goto errout;
322
323 ops = genl_get_cmd(hdr->cmd, family);
324 if (ops == NULL) {
325 err = -EOPNOTSUPP;
326 goto errout;
327 }
328
Darrel Goeddelc7bdb542006-06-27 13:26:11 -0700329 if ((ops->flags & GENL_ADMIN_PERM) && security_netlink_recv(skb, CAP_NET_ADMIN)) {
Thomas Graf482a8522005-11-10 02:25:56 +0100330 err = -EPERM;
331 goto errout;
332 }
333
334 if (nlh->nlmsg_flags & NLM_F_DUMP) {
335 if (ops->dumpit == NULL) {
336 err = -EOPNOTSUPP;
337 goto errout;
338 }
339
340 *errp = err = netlink_dump_start(genl_sock, skb, nlh,
Jamal Hadi Salima4d13662006-12-01 20:07:42 -0800341 ops->dumpit, ops->done);
Thomas Graf482a8522005-11-10 02:25:56 +0100342 if (err == 0)
343 skb_pull(skb, min(NLMSG_ALIGN(nlh->nlmsg_len),
344 skb->len));
345 return -1;
346 }
347
348 if (ops->doit == NULL) {
349 err = -EOPNOTSUPP;
350 goto errout;
351 }
352
353 if (family->attrbuf) {
354 err = nlmsg_parse(nlh, hdrlen, family->attrbuf, family->maxattr,
355 ops->policy);
356 if (err < 0)
357 goto errout;
358 }
359
360 info.snd_seq = nlh->nlmsg_seq;
361 info.snd_pid = NETLINK_CB(skb).pid;
362 info.nlhdr = nlh;
363 info.genlhdr = nlmsg_data(nlh);
364 info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
365 info.attrs = family->attrbuf;
366
367 *errp = err = ops->doit(skb, &info);
368 return err;
369
370ignore:
371 return 0;
372
373errout:
374 *errp = err;
375 return -1;
376}
377
378static void genl_rcv(struct sock *sk, int len)
379{
380 unsigned int qlen = 0;
381
382 do {
383 if (genl_trylock())
384 return;
Jamal Hadi Salime200bd82006-02-13 15:51:24 -0800385 netlink_run_queue(sk, &qlen, genl_rcv_msg);
Thomas Graf482a8522005-11-10 02:25:56 +0100386 genl_unlock();
387 } while (qlen && genl_sock && genl_sock->sk_receive_queue.qlen);
388}
389
390/**************************************************************************
391 * Controller
392 **************************************************************************/
393
Thomas Graf17c157c2006-11-14 19:46:02 -0800394static struct genl_family genl_ctrl = {
395 .id = GENL_ID_CTRL,
396 .name = "nlctrl",
Jamal Hadi Salim334c29a2006-12-04 19:31:51 -0800397 .version = 0x2,
Thomas Graf17c157c2006-11-14 19:46:02 -0800398 .maxattr = CTRL_ATTR_MAX,
399};
400
Thomas Graf482a8522005-11-10 02:25:56 +0100401static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
402 u32 flags, struct sk_buff *skb, u8 cmd)
403{
404 void *hdr;
405
Thomas Graf17c157c2006-11-14 19:46:02 -0800406 hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
Thomas Graf482a8522005-11-10 02:25:56 +0100407 if (hdr == NULL)
408 return -1;
409
410 NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, family->name);
411 NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, family->id);
Thomas Grafeb328112006-09-18 00:01:59 -0700412 NLA_PUT_U32(skb, CTRL_ATTR_VERSION, family->version);
413 NLA_PUT_U32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize);
414 NLA_PUT_U32(skb, CTRL_ATTR_MAXATTR, family->maxattr);
415
Thomas Grafe94ef682006-11-23 11:44:37 -0800416 if (!list_empty(&family->ops_list)) {
417 struct nlattr *nla_ops;
418 struct genl_ops *ops;
419 int idx = 1;
Thomas Grafeb328112006-09-18 00:01:59 -0700420
Thomas Grafe94ef682006-11-23 11:44:37 -0800421 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
422 if (nla_ops == NULL)
Thomas Grafeb328112006-09-18 00:01:59 -0700423 goto nla_put_failure;
424
Thomas Grafe94ef682006-11-23 11:44:37 -0800425 list_for_each_entry(ops, &family->ops_list, ops_list) {
426 struct nlattr *nest;
Thomas Grafeb328112006-09-18 00:01:59 -0700427
Thomas Grafe94ef682006-11-23 11:44:37 -0800428 nest = nla_nest_start(skb, idx++);
429 if (nest == NULL)
430 goto nla_put_failure;
Thomas Grafeb328112006-09-18 00:01:59 -0700431
Thomas Grafe94ef682006-11-23 11:44:37 -0800432 NLA_PUT_U32(skb, CTRL_ATTR_OP_ID, ops->cmd);
433 NLA_PUT_U32(skb, CTRL_ATTR_OP_FLAGS, ops->flags);
Thomas Grafeb328112006-09-18 00:01:59 -0700434
Thomas Grafe94ef682006-11-23 11:44:37 -0800435 nla_nest_end(skb, nest);
436 }
437
438 nla_nest_end(skb, nla_ops);
Thomas Grafeb328112006-09-18 00:01:59 -0700439 }
440
Thomas Graf482a8522005-11-10 02:25:56 +0100441 return genlmsg_end(skb, hdr);
442
443nla_put_failure:
444 return genlmsg_cancel(skb, hdr);
445}
446
447static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
448{
449
450 int i, n = 0;
451 struct genl_family *rt;
452 int chains_to_skip = cb->args[0];
453 int fams_to_skip = cb->args[1];
454
Thomas Grafeb328112006-09-18 00:01:59 -0700455 if (chains_to_skip != 0)
456 genl_lock();
457
Thomas Graf482a8522005-11-10 02:25:56 +0100458 for (i = 0; i < GENL_FAM_TAB_SIZE; i++) {
459 if (i < chains_to_skip)
460 continue;
461 n = 0;
462 list_for_each_entry(rt, genl_family_chain(i), family_list) {
463 if (++n < fams_to_skip)
464 continue;
465 if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).pid,
466 cb->nlh->nlmsg_seq, NLM_F_MULTI,
467 skb, CTRL_CMD_NEWFAMILY) < 0)
468 goto errout;
469 }
470
471 fams_to_skip = 0;
472 }
473
474errout:
Thomas Grafeb328112006-09-18 00:01:59 -0700475 if (chains_to_skip != 0)
476 genl_unlock();
477
Thomas Graf482a8522005-11-10 02:25:56 +0100478 cb->args[0] = i;
479 cb->args[1] = n;
480
481 return skb->len;
482}
483
484static struct sk_buff *ctrl_build_msg(struct genl_family *family, u32 pid,
Per Lidenb461d2f2006-01-03 14:13:29 -0800485 int seq, u8 cmd)
Thomas Graf482a8522005-11-10 02:25:56 +0100486{
487 struct sk_buff *skb;
488 int err;
489
Thomas Graf339bf982006-11-10 14:10:15 -0800490 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
Thomas Graf482a8522005-11-10 02:25:56 +0100491 if (skb == NULL)
492 return ERR_PTR(-ENOBUFS);
493
494 err = ctrl_fill_info(family, pid, seq, 0, skb, cmd);
495 if (err < 0) {
496 nlmsg_free(skb);
497 return ERR_PTR(err);
498 }
499
500 return skb;
501}
502
503static struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] __read_mostly = {
504 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 },
Thomas Graf5176f912006-08-26 20:13:18 -0700505 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
506 .len = GENL_NAMSIZ - 1 },
Thomas Graf482a8522005-11-10 02:25:56 +0100507};
508
509static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
510{
511 struct sk_buff *msg;
512 struct genl_family *res = NULL;
513 int err = -EINVAL;
514
515 if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
516 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
517 res = genl_family_find_byid(id);
518 }
519
520 if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
Thomas Graf5176f912006-08-26 20:13:18 -0700521 char *name;
Thomas Graf482a8522005-11-10 02:25:56 +0100522
Thomas Graf5176f912006-08-26 20:13:18 -0700523 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
Thomas Graf482a8522005-11-10 02:25:56 +0100524 res = genl_family_find_byname(name);
525 }
526
527 if (res == NULL) {
528 err = -ENOENT;
529 goto errout;
530 }
531
532 msg = ctrl_build_msg(res, info->snd_pid, info->snd_seq,
533 CTRL_CMD_NEWFAMILY);
534 if (IS_ERR(msg)) {
535 err = PTR_ERR(msg);
536 goto errout;
537 }
538
Thomas Graf81878d22006-11-14 19:45:27 -0800539 err = genlmsg_reply(msg, info);
Thomas Graf482a8522005-11-10 02:25:56 +0100540errout:
541 return err;
542}
543
544static int genl_ctrl_event(int event, void *data)
545{
546 struct sk_buff *msg;
547
548 if (genl_sock == NULL)
549 return 0;
550
551 switch (event) {
552 case CTRL_CMD_NEWFAMILY:
553 case CTRL_CMD_DELFAMILY:
554 msg = ctrl_build_msg(data, 0, 0, event);
555 if (IS_ERR(msg))
556 return PTR_ERR(msg);
557
Thomas Grafd387f6a2006-08-15 00:31:06 -0700558 genlmsg_multicast(msg, 0, GENL_ID_CTRL, GFP_KERNEL);
Thomas Graf482a8522005-11-10 02:25:56 +0100559 break;
560 }
561
562 return 0;
563}
564
565static struct genl_ops genl_ctrl_ops = {
566 .cmd = CTRL_CMD_GETFAMILY,
567 .doit = ctrl_getfamily,
568 .dumpit = ctrl_dumpfamily,
569 .policy = ctrl_policy,
570};
571
Thomas Graf482a8522005-11-10 02:25:56 +0100572static int __init genl_init(void)
573{
574 int i, err;
575
576 for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
577 INIT_LIST_HEAD(&family_ht[i]);
578
579 err = genl_register_family(&genl_ctrl);
580 if (err < 0)
581 goto errout;
582
583 err = genl_register_ops(&genl_ctrl, &genl_ctrl_ops);
584 if (err < 0)
585 goto errout_register;
586
587 netlink_set_nonroot(NETLINK_GENERIC, NL_NONROOT_RECV);
588 genl_sock = netlink_kernel_create(NETLINK_GENERIC, GENL_MAX_ID,
589 genl_rcv, THIS_MODULE);
Jamal Hadi Salime200bd82006-02-13 15:51:24 -0800590 if (genl_sock == NULL)
Thomas Graf482a8522005-11-10 02:25:56 +0100591 panic("GENL: Cannot initialize generic netlink\n");
Thomas Graf482a8522005-11-10 02:25:56 +0100592
593 return 0;
594
595errout_register:
596 genl_unregister_family(&genl_ctrl);
597errout:
598 panic("GENL: Cannot register controller: %d\n", err);
Thomas Graf482a8522005-11-10 02:25:56 +0100599}
600
601subsys_initcall(genl_init);
602
603EXPORT_SYMBOL(genl_sock);
604EXPORT_SYMBOL(genl_register_ops);
605EXPORT_SYMBOL(genl_unregister_ops);
606EXPORT_SYMBOL(genl_register_family);
607EXPORT_SYMBOL(genl_unregister_family);