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7672d0b5 EP |
1 | /* |
2 | * connector.c | |
3 | * | |
4 | * 2004-2005 Copyright (c) Evgeniy Polyakov <johnpol@2ka.mipt.ru> | |
5 | * All rights reserved. | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License as published by | |
9 | * the Free Software Foundation; either version 2 of the License, or | |
10 | * (at your option) any later version. | |
11 | * | |
12 | * This program is distributed in the hope that it will be useful, | |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | * GNU General Public License for more details. | |
16 | * | |
17 | * You should have received a copy of the GNU General Public License | |
18 | * along with this program; if not, write to the Free Software | |
19 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
20 | */ | |
21 | ||
22 | #include <linux/kernel.h> | |
23 | #include <linux/module.h> | |
24 | #include <linux/list.h> | |
25 | #include <linux/skbuff.h> | |
26 | #include <linux/netlink.h> | |
27 | #include <linux/moduleparam.h> | |
28 | #include <linux/connector.h> | |
8ed965d6 | 29 | #include <linux/mutex.h> |
7672d0b5 EP |
30 | |
31 | #include <net/sock.h> | |
32 | ||
33 | MODULE_LICENSE("GPL"); | |
34 | MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>"); | |
35 | MODULE_DESCRIPTION("Generic userspace <-> kernelspace connector."); | |
36 | ||
37 | static u32 cn_idx = CN_IDX_CONNECTOR; | |
38 | static u32 cn_val = CN_VAL_CONNECTOR; | |
39 | ||
40 | module_param(cn_idx, uint, 0); | |
41 | module_param(cn_val, uint, 0); | |
42 | MODULE_PARM_DESC(cn_idx, "Connector's main device idx."); | |
43 | MODULE_PARM_DESC(cn_val, "Connector's main device val."); | |
44 | ||
8ed965d6 | 45 | static DEFINE_MUTEX(notify_lock); |
7672d0b5 EP |
46 | static LIST_HEAD(notify_list); |
47 | ||
48 | static struct cn_dev cdev; | |
49 | ||
50 | int cn_already_initialized = 0; | |
51 | ||
52 | /* | |
53 | * msg->seq and msg->ack are used to determine message genealogy. | |
54 | * When someone sends message it puts there locally unique sequence | |
55 | * and random acknowledge numbers. Sequence number may be copied into | |
56 | * nlmsghdr->nlmsg_seq too. | |
57 | * | |
58 | * Sequence number is incremented with each message to be sent. | |
59 | * | |
60 | * If we expect reply to our message then the sequence number in | |
61 | * received message MUST be the same as in original message, and | |
62 | * acknowledge number MUST be the same + 1. | |
63 | * | |
64 | * If we receive a message and its sequence number is not equal to the | |
65 | * one we are expecting then it is a new message. | |
66 | * | |
67 | * If we receive a message and its sequence number is the same as one | |
68 | * we are expecting but it's acknowledgement number is not equal to | |
69 | * the acknowledgement number in the original message + 1, then it is | |
70 | * a new message. | |
71 | * | |
72 | */ | |
dd0fc66f | 73 | int cn_netlink_send(struct cn_msg *msg, u32 __group, gfp_t gfp_mask) |
7672d0b5 EP |
74 | { |
75 | struct cn_callback_entry *__cbq; | |
76 | unsigned int size; | |
77 | struct sk_buff *skb; | |
78 | struct nlmsghdr *nlh; | |
79 | struct cn_msg *data; | |
80 | struct cn_dev *dev = &cdev; | |
81 | u32 group = 0; | |
82 | int found = 0; | |
83 | ||
84 | if (!__group) { | |
85 | spin_lock_bh(&dev->cbdev->queue_lock); | |
86 | list_for_each_entry(__cbq, &dev->cbdev->queue_list, | |
87 | callback_entry) { | |
acd042bb | 88 | if (cn_cb_equal(&__cbq->id.id, &msg->id)) { |
7672d0b5 EP |
89 | found = 1; |
90 | group = __cbq->group; | |
fd00eecc | 91 | break; |
7672d0b5 EP |
92 | } |
93 | } | |
94 | spin_unlock_bh(&dev->cbdev->queue_lock); | |
95 | ||
96 | if (!found) | |
97 | return -ENODEV; | |
98 | } else { | |
99 | group = __group; | |
100 | } | |
101 | ||
b191ba0d EP |
102 | if (!netlink_has_listeners(dev->nls, group)) |
103 | return -ESRCH; | |
104 | ||
7672d0b5 EP |
105 | size = NLMSG_SPACE(sizeof(*msg) + msg->len); |
106 | ||
107 | skb = alloc_skb(size, gfp_mask); | |
108 | if (!skb) | |
109 | return -ENOMEM; | |
110 | ||
111 | nlh = NLMSG_PUT(skb, 0, msg->seq, NLMSG_DONE, size - sizeof(*nlh)); | |
112 | ||
113 | data = NLMSG_DATA(nlh); | |
114 | ||
115 | memcpy(data, msg, sizeof(*data) + msg->len); | |
116 | ||
117 | NETLINK_CB(skb).dst_group = group; | |
118 | ||
b191ba0d | 119 | return netlink_broadcast(dev->nls, skb, 0, group, gfp_mask); |
7672d0b5 EP |
120 | |
121 | nlmsg_failure: | |
122 | kfree_skb(skb); | |
123 | return -EINVAL; | |
124 | } | |
deb0e9b2 | 125 | EXPORT_SYMBOL_GPL(cn_netlink_send); |
7672d0b5 EP |
126 | |
127 | /* | |
128 | * Callback helper - queues work and setup destructor for given data. | |
129 | */ | |
130 | static int cn_call_callback(struct cn_msg *msg, void (*destruct_data)(void *), void *data) | |
131 | { | |
05e52dd7 | 132 | struct cn_callback_entry *__cbq, *__new_cbq; |
7672d0b5 | 133 | struct cn_dev *dev = &cdev; |
acd042bb | 134 | int err = -ENODEV; |
7672d0b5 EP |
135 | |
136 | spin_lock_bh(&dev->cbdev->queue_lock); | |
137 | list_for_each_entry(__cbq, &dev->cbdev->queue_list, callback_entry) { | |
acd042bb | 138 | if (cn_cb_equal(&__cbq->id.id, &msg->id)) { |
a240d9f1 | 139 | if (likely(!work_pending(&__cbq->work) && |
acd042bb EP |
140 | __cbq->data.ddata == NULL)) { |
141 | __cbq->data.callback_priv = msg; | |
7672d0b5 | 142 | |
acd042bb EP |
143 | __cbq->data.ddata = data; |
144 | __cbq->data.destruct_data = destruct_data; | |
7672d0b5 | 145 | |
a240d9f1 EP |
146 | if (queue_work(dev->cbdev->cn_queue, |
147 | &__cbq->work)) | |
acd042bb | 148 | err = 0; |
134d99e3 LZ |
149 | else |
150 | err = -EINVAL; | |
7672d0b5 | 151 | } else { |
acd042bb EP |
152 | struct cn_callback_data *d; |
153 | ||
05e52dd7 PR |
154 | err = -ENOMEM; |
155 | __new_cbq = kzalloc(sizeof(struct cn_callback_entry), GFP_ATOMIC); | |
156 | if (__new_cbq) { | |
157 | d = &__new_cbq->data; | |
acd042bb EP |
158 | d->callback_priv = msg; |
159 | d->callback = __cbq->data.callback; | |
160 | d->ddata = data; | |
161 | d->destruct_data = destruct_data; | |
05e52dd7 | 162 | d->free = __new_cbq; |
acd042bb | 163 | |
05e52dd7 | 164 | INIT_WORK(&__new_cbq->work, |
a240d9f1 | 165 | &cn_queue_wrapper); |
05e52dd7 | 166 | |
a240d9f1 | 167 | if (queue_work(dev->cbdev->cn_queue, |
05e52dd7 | 168 | &__new_cbq->work)) |
acd042bb EP |
169 | err = 0; |
170 | else { | |
05e52dd7 | 171 | kfree(__new_cbq); |
acd042bb EP |
172 | err = -EINVAL; |
173 | } | |
05e52dd7 | 174 | } |
7672d0b5 EP |
175 | } |
176 | break; | |
177 | } | |
178 | } | |
179 | spin_unlock_bh(&dev->cbdev->queue_lock); | |
180 | ||
acd042bb | 181 | return err; |
7672d0b5 EP |
182 | } |
183 | ||
184 | /* | |
185 | * Skb receive helper - checks skb and msg size and calls callback | |
186 | * helper. | |
187 | */ | |
188 | static int __cn_rx_skb(struct sk_buff *skb, struct nlmsghdr *nlh) | |
189 | { | |
190 | u32 pid, uid, seq, group; | |
191 | struct cn_msg *msg; | |
192 | ||
193 | pid = NETLINK_CREDS(skb)->pid; | |
194 | uid = NETLINK_CREDS(skb)->uid; | |
195 | seq = nlh->nlmsg_seq; | |
196 | group = NETLINK_CB((skb)).dst_group; | |
197 | msg = NLMSG_DATA(nlh); | |
198 | ||
199 | return cn_call_callback(msg, (void (*)(void *))kfree_skb, skb); | |
200 | } | |
201 | ||
202 | /* | |
203 | * Main netlink receiving function. | |
204 | * | |
205 | * It checks skb and netlink header sizes and calls the skb receive | |
206 | * helper with a shared skb. | |
207 | */ | |
208 | static void cn_rx_skb(struct sk_buff *__skb) | |
209 | { | |
210 | struct nlmsghdr *nlh; | |
211 | u32 len; | |
212 | int err; | |
213 | struct sk_buff *skb; | |
214 | ||
215 | skb = skb_get(__skb); | |
216 | ||
217 | if (skb->len >= NLMSG_SPACE(0)) { | |
b529ccf2 | 218 | nlh = nlmsg_hdr(skb); |
7672d0b5 EP |
219 | |
220 | if (nlh->nlmsg_len < sizeof(struct cn_msg) || | |
221 | skb->len < nlh->nlmsg_len || | |
222 | nlh->nlmsg_len > CONNECTOR_MAX_MSG_SIZE) { | |
223 | kfree_skb(skb); | |
6cf92e98 | 224 | return; |
7672d0b5 EP |
225 | } |
226 | ||
227 | len = NLMSG_ALIGN(nlh->nlmsg_len); | |
228 | if (len > skb->len) | |
229 | len = skb->len; | |
230 | ||
231 | err = __cn_rx_skb(skb, nlh); | |
232 | if (err < 0) | |
233 | kfree_skb(skb); | |
234 | } | |
7672d0b5 EP |
235 | } |
236 | ||
7672d0b5 EP |
237 | /* |
238 | * Notification routing. | |
239 | * | |
240 | * Gets id and checks if there are notification request for it's idx | |
241 | * and val. If there are such requests notify the listeners with the | |
242 | * given notify event. | |
243 | * | |
244 | */ | |
245 | static void cn_notify(struct cb_id *id, u32 notify_event) | |
246 | { | |
247 | struct cn_ctl_entry *ent; | |
248 | ||
8ed965d6 | 249 | mutex_lock(¬ify_lock); |
7672d0b5 EP |
250 | list_for_each_entry(ent, ¬ify_list, notify_entry) { |
251 | int i; | |
252 | struct cn_notify_req *req; | |
253 | struct cn_ctl_msg *ctl = ent->msg; | |
254 | int idx_found, val_found; | |
255 | ||
256 | idx_found = val_found = 0; | |
257 | ||
258 | req = (struct cn_notify_req *)ctl->data; | |
259 | for (i = 0; i < ctl->idx_notify_num; ++i, ++req) { | |
260 | if (id->idx >= req->first && | |
261 | id->idx < req->first + req->range) { | |
262 | idx_found = 1; | |
263 | break; | |
264 | } | |
265 | } | |
266 | ||
267 | for (i = 0; i < ctl->val_notify_num; ++i, ++req) { | |
268 | if (id->val >= req->first && | |
269 | id->val < req->first + req->range) { | |
270 | val_found = 1; | |
271 | break; | |
272 | } | |
273 | } | |
274 | ||
275 | if (idx_found && val_found) { | |
276 | struct cn_msg m = { .ack = notify_event, }; | |
277 | ||
278 | memcpy(&m.id, id, sizeof(m.id)); | |
279 | cn_netlink_send(&m, ctl->group, GFP_KERNEL); | |
280 | } | |
281 | } | |
8ed965d6 | 282 | mutex_unlock(¬ify_lock); |
7672d0b5 EP |
283 | } |
284 | ||
285 | /* | |
286 | * Callback add routing - adds callback with given ID and name. | |
287 | * If there is registered callback with the same ID it will not be added. | |
288 | * | |
289 | * May sleep. | |
290 | */ | |
291 | int cn_add_callback(struct cb_id *id, char *name, void (*callback)(void *)) | |
292 | { | |
293 | int err; | |
294 | struct cn_dev *dev = &cdev; | |
7672d0b5 | 295 | |
d6cc7f1a EP |
296 | if (!cn_already_initialized) |
297 | return -EAGAIN; | |
298 | ||
acd042bb EP |
299 | err = cn_queue_add_callback(dev->cbdev, name, id, callback); |
300 | if (err) | |
7672d0b5 | 301 | return err; |
7672d0b5 EP |
302 | |
303 | cn_notify(id, 0); | |
304 | ||
305 | return 0; | |
306 | } | |
deb0e9b2 | 307 | EXPORT_SYMBOL_GPL(cn_add_callback); |
7672d0b5 EP |
308 | |
309 | /* | |
310 | * Callback remove routing - removes callback | |
311 | * with given ID. | |
312 | * If there is no registered callback with given | |
313 | * ID nothing happens. | |
314 | * | |
315 | * May sleep while waiting for reference counter to become zero. | |
316 | */ | |
317 | void cn_del_callback(struct cb_id *id) | |
318 | { | |
319 | struct cn_dev *dev = &cdev; | |
320 | ||
321 | cn_queue_del_callback(dev->cbdev, id); | |
322 | cn_notify(id, 1); | |
323 | } | |
deb0e9b2 | 324 | EXPORT_SYMBOL_GPL(cn_del_callback); |
7672d0b5 EP |
325 | |
326 | /* | |
327 | * Checks two connector's control messages to be the same. | |
328 | * Returns 1 if they are the same or if the first one is corrupted. | |
329 | */ | |
330 | static int cn_ctl_msg_equals(struct cn_ctl_msg *m1, struct cn_ctl_msg *m2) | |
331 | { | |
332 | int i; | |
333 | struct cn_notify_req *req1, *req2; | |
334 | ||
335 | if (m1->idx_notify_num != m2->idx_notify_num) | |
336 | return 0; | |
337 | ||
338 | if (m1->val_notify_num != m2->val_notify_num) | |
339 | return 0; | |
340 | ||
341 | if (m1->len != m2->len) | |
342 | return 0; | |
343 | ||
344 | if ((m1->idx_notify_num + m1->val_notify_num) * sizeof(*req1) != | |
345 | m1->len) | |
346 | return 1; | |
347 | ||
348 | req1 = (struct cn_notify_req *)m1->data; | |
349 | req2 = (struct cn_notify_req *)m2->data; | |
350 | ||
351 | for (i = 0; i < m1->idx_notify_num; ++i) { | |
352 | if (req1->first != req2->first || req1->range != req2->range) | |
353 | return 0; | |
354 | req1++; | |
355 | req2++; | |
356 | } | |
357 | ||
358 | for (i = 0; i < m1->val_notify_num; ++i) { | |
359 | if (req1->first != req2->first || req1->range != req2->range) | |
360 | return 0; | |
361 | req1++; | |
362 | req2++; | |
363 | } | |
364 | ||
365 | return 1; | |
366 | } | |
367 | ||
368 | /* | |
369 | * Main connector device's callback. | |
370 | * | |
371 | * Used for notification of a request's processing. | |
372 | */ | |
373 | static void cn_callback(void *data) | |
374 | { | |
375 | struct cn_msg *msg = data; | |
376 | struct cn_ctl_msg *ctl; | |
377 | struct cn_ctl_entry *ent; | |
378 | u32 size; | |
379 | ||
380 | if (msg->len < sizeof(*ctl)) | |
381 | return; | |
382 | ||
383 | ctl = (struct cn_ctl_msg *)msg->data; | |
384 | ||
385 | size = (sizeof(*ctl) + ((ctl->idx_notify_num + | |
386 | ctl->val_notify_num) * | |
387 | sizeof(struct cn_notify_req))); | |
388 | ||
389 | if (msg->len != size) | |
390 | return; | |
391 | ||
392 | if (ctl->len + sizeof(*ctl) != msg->len) | |
393 | return; | |
394 | ||
395 | /* | |
396 | * Remove notification. | |
397 | */ | |
398 | if (ctl->group == 0) { | |
399 | struct cn_ctl_entry *n; | |
400 | ||
8ed965d6 | 401 | mutex_lock(¬ify_lock); |
7672d0b5 EP |
402 | list_for_each_entry_safe(ent, n, ¬ify_list, notify_entry) { |
403 | if (cn_ctl_msg_equals(ent->msg, ctl)) { | |
404 | list_del(&ent->notify_entry); | |
405 | kfree(ent); | |
406 | } | |
407 | } | |
8ed965d6 | 408 | mutex_unlock(¬ify_lock); |
7672d0b5 EP |
409 | |
410 | return; | |
411 | } | |
412 | ||
413 | size += sizeof(*ent); | |
414 | ||
415 | ent = kzalloc(size, GFP_KERNEL); | |
416 | if (!ent) | |
417 | return; | |
418 | ||
419 | ent->msg = (struct cn_ctl_msg *)(ent + 1); | |
420 | ||
421 | memcpy(ent->msg, ctl, size - sizeof(*ent)); | |
422 | ||
8ed965d6 | 423 | mutex_lock(¬ify_lock); |
7672d0b5 | 424 | list_add(&ent->notify_entry, ¬ify_list); |
8ed965d6 | 425 | mutex_unlock(¬ify_lock); |
7672d0b5 EP |
426 | } |
427 | ||
d6cc7f1a | 428 | static int __devinit cn_init(void) |
7672d0b5 EP |
429 | { |
430 | struct cn_dev *dev = &cdev; | |
431 | int err; | |
432 | ||
cd40b7d3 | 433 | dev->input = cn_rx_skb; |
7672d0b5 EP |
434 | dev->id.idx = cn_idx; |
435 | dev->id.val = cn_val; | |
436 | ||
b4b51029 | 437 | dev->nls = netlink_kernel_create(&init_net, NETLINK_CONNECTOR, |
7672d0b5 | 438 | CN_NETLINK_USERS + 0xf, |
af65bdfc | 439 | dev->input, NULL, THIS_MODULE); |
7672d0b5 EP |
440 | if (!dev->nls) |
441 | return -EIO; | |
442 | ||
443 | dev->cbdev = cn_queue_alloc_dev("cqueue", dev->nls); | |
444 | if (!dev->cbdev) { | |
445 | if (dev->nls->sk_socket) | |
446 | sock_release(dev->nls->sk_socket); | |
447 | return -EINVAL; | |
448 | } | |
d6cc7f1a EP |
449 | |
450 | cn_already_initialized = 1; | |
7672d0b5 EP |
451 | |
452 | err = cn_add_callback(&dev->id, "connector", &cn_callback); | |
453 | if (err) { | |
d6cc7f1a | 454 | cn_already_initialized = 0; |
7672d0b5 EP |
455 | cn_queue_free_dev(dev->cbdev); |
456 | if (dev->nls->sk_socket) | |
457 | sock_release(dev->nls->sk_socket); | |
458 | return -EINVAL; | |
459 | } | |
460 | ||
7672d0b5 EP |
461 | return 0; |
462 | } | |
463 | ||
d6cc7f1a | 464 | static void __devexit cn_fini(void) |
7672d0b5 EP |
465 | { |
466 | struct cn_dev *dev = &cdev; | |
467 | ||
468 | cn_already_initialized = 0; | |
469 | ||
470 | cn_del_callback(&dev->id); | |
471 | cn_queue_free_dev(dev->cbdev); | |
472 | if (dev->nls->sk_socket) | |
473 | sock_release(dev->nls->sk_socket); | |
474 | } | |
475 | ||
d6cc7f1a | 476 | subsys_initcall(cn_init); |
7672d0b5 | 477 | module_exit(cn_fini); |