Commit | Line | Data |
---|---|---|
7672d0b5 EP |
1 | /* |
2 | * connector.c | |
1a5645bc | 3 | * |
7672d0b5 EP |
4 | * 2004-2005 Copyright (c) Evgeniy Polyakov <johnpol@2ka.mipt.ru> |
5 | * All rights reserved. | |
1a5645bc | 6 | * |
7672d0b5 EP |
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> |
a0a61a60 LZ |
30 | #include <linux/proc_fs.h> |
31 | #include <linux/spinlock.h> | |
7672d0b5 EP |
32 | |
33 | #include <net/sock.h> | |
34 | ||
35 | MODULE_LICENSE("GPL"); | |
36 | MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>"); | |
37 | MODULE_DESCRIPTION("Generic userspace <-> kernelspace connector."); | |
38 | ||
39 | static u32 cn_idx = CN_IDX_CONNECTOR; | |
40 | static u32 cn_val = CN_VAL_CONNECTOR; | |
41 | ||
42 | module_param(cn_idx, uint, 0); | |
43 | module_param(cn_val, uint, 0); | |
44 | MODULE_PARM_DESC(cn_idx, "Connector's main device idx."); | |
45 | MODULE_PARM_DESC(cn_val, "Connector's main device val."); | |
46 | ||
8ed965d6 | 47 | static DEFINE_MUTEX(notify_lock); |
7672d0b5 EP |
48 | static LIST_HEAD(notify_list); |
49 | ||
50 | static struct cn_dev cdev; | |
51 | ||
78374676 | 52 | static int cn_already_initialized; |
7672d0b5 EP |
53 | |
54 | /* | |
55 | * msg->seq and msg->ack are used to determine message genealogy. | |
56 | * When someone sends message it puts there locally unique sequence | |
57 | * and random acknowledge numbers. Sequence number may be copied into | |
58 | * nlmsghdr->nlmsg_seq too. | |
59 | * | |
60 | * Sequence number is incremented with each message to be sent. | |
61 | * | |
62 | * If we expect reply to our message then the sequence number in | |
63 | * received message MUST be the same as in original message, and | |
64 | * acknowledge number MUST be the same + 1. | |
65 | * | |
66 | * If we receive a message and its sequence number is not equal to the | |
67 | * one we are expecting then it is a new message. | |
68 | * | |
69 | * If we receive a message and its sequence number is the same as one | |
70 | * we are expecting but it's acknowledgement number is not equal to | |
71 | * the acknowledgement number in the original message + 1, then it is | |
72 | * a new message. | |
73 | * | |
74 | */ | |
dd0fc66f | 75 | int cn_netlink_send(struct cn_msg *msg, u32 __group, gfp_t gfp_mask) |
7672d0b5 EP |
76 | { |
77 | struct cn_callback_entry *__cbq; | |
78 | unsigned int size; | |
79 | struct sk_buff *skb; | |
80 | struct nlmsghdr *nlh; | |
81 | struct cn_msg *data; | |
82 | struct cn_dev *dev = &cdev; | |
83 | u32 group = 0; | |
84 | int found = 0; | |
85 | ||
86 | if (!__group) { | |
87 | spin_lock_bh(&dev->cbdev->queue_lock); | |
88 | list_for_each_entry(__cbq, &dev->cbdev->queue_list, | |
89 | callback_entry) { | |
acd042bb | 90 | if (cn_cb_equal(&__cbq->id.id, &msg->id)) { |
7672d0b5 EP |
91 | found = 1; |
92 | group = __cbq->group; | |
fd00eecc | 93 | break; |
7672d0b5 EP |
94 | } |
95 | } | |
96 | spin_unlock_bh(&dev->cbdev->queue_lock); | |
97 | ||
98 | if (!found) | |
99 | return -ENODEV; | |
100 | } else { | |
101 | group = __group; | |
102 | } | |
103 | ||
b191ba0d EP |
104 | if (!netlink_has_listeners(dev->nls, group)) |
105 | return -ESRCH; | |
106 | ||
7672d0b5 EP |
107 | size = NLMSG_SPACE(sizeof(*msg) + msg->len); |
108 | ||
109 | skb = alloc_skb(size, gfp_mask); | |
110 | if (!skb) | |
111 | return -ENOMEM; | |
112 | ||
113 | nlh = NLMSG_PUT(skb, 0, msg->seq, NLMSG_DONE, size - sizeof(*nlh)); | |
114 | ||
115 | data = NLMSG_DATA(nlh); | |
116 | ||
117 | memcpy(data, msg, sizeof(*data) + msg->len); | |
118 | ||
119 | NETLINK_CB(skb).dst_group = group; | |
120 | ||
b191ba0d | 121 | return netlink_broadcast(dev->nls, skb, 0, group, gfp_mask); |
7672d0b5 EP |
122 | |
123 | nlmsg_failure: | |
124 | kfree_skb(skb); | |
125 | return -EINVAL; | |
126 | } | |
deb0e9b2 | 127 | EXPORT_SYMBOL_GPL(cn_netlink_send); |
7672d0b5 EP |
128 | |
129 | /* | |
130 | * Callback helper - queues work and setup destructor for given data. | |
131 | */ | |
132 | static int cn_call_callback(struct cn_msg *msg, void (*destruct_data)(void *), void *data) | |
133 | { | |
05e52dd7 | 134 | struct cn_callback_entry *__cbq, *__new_cbq; |
7672d0b5 | 135 | struct cn_dev *dev = &cdev; |
acd042bb | 136 | int err = -ENODEV; |
7672d0b5 EP |
137 | |
138 | spin_lock_bh(&dev->cbdev->queue_lock); | |
139 | list_for_each_entry(__cbq, &dev->cbdev->queue_list, callback_entry) { | |
acd042bb | 140 | if (cn_cb_equal(&__cbq->id.id, &msg->id)) { |
a240d9f1 | 141 | if (likely(!work_pending(&__cbq->work) && |
acd042bb EP |
142 | __cbq->data.ddata == NULL)) { |
143 | __cbq->data.callback_priv = msg; | |
7672d0b5 | 144 | |
acd042bb EP |
145 | __cbq->data.ddata = data; |
146 | __cbq->data.destruct_data = destruct_data; | |
7672d0b5 | 147 | |
1a5645bc | 148 | if (queue_cn_work(__cbq, &__cbq->work)) |
acd042bb | 149 | err = 0; |
134d99e3 LZ |
150 | else |
151 | err = -EINVAL; | |
7672d0b5 | 152 | } else { |
acd042bb | 153 | struct cn_callback_data *d; |
1a5645bc | 154 | |
05e52dd7 PR |
155 | err = -ENOMEM; |
156 | __new_cbq = kzalloc(sizeof(struct cn_callback_entry), GFP_ATOMIC); | |
157 | if (__new_cbq) { | |
158 | d = &__new_cbq->data; | |
acd042bb EP |
159 | d->callback_priv = msg; |
160 | d->callback = __cbq->data.callback; | |
161 | d->ddata = data; | |
162 | d->destruct_data = destruct_data; | |
05e52dd7 | 163 | d->free = __new_cbq; |
acd042bb | 164 | |
1a5645bc FW |
165 | __new_cbq->pdev = __cbq->pdev; |
166 | ||
05e52dd7 | 167 | INIT_WORK(&__new_cbq->work, |
a240d9f1 | 168 | &cn_queue_wrapper); |
05e52dd7 | 169 | |
1a5645bc | 170 | if (queue_cn_work(__new_cbq, |
05e52dd7 | 171 | &__new_cbq->work)) |
acd042bb EP |
172 | err = 0; |
173 | else { | |
05e52dd7 | 174 | kfree(__new_cbq); |
acd042bb EP |
175 | err = -EINVAL; |
176 | } | |
05e52dd7 | 177 | } |
7672d0b5 EP |
178 | } |
179 | break; | |
180 | } | |
181 | } | |
182 | spin_unlock_bh(&dev->cbdev->queue_lock); | |
183 | ||
acd042bb | 184 | return err; |
7672d0b5 EP |
185 | } |
186 | ||
7672d0b5 EP |
187 | /* |
188 | * Main netlink receiving function. | |
189 | * | |
00f5e06c | 190 | * It checks skb, netlink header and msg sizes, and calls callback helper. |
7672d0b5 EP |
191 | */ |
192 | static void cn_rx_skb(struct sk_buff *__skb) | |
193 | { | |
00f5e06c | 194 | struct cn_msg *msg; |
7672d0b5 | 195 | struct nlmsghdr *nlh; |
7672d0b5 EP |
196 | int err; |
197 | struct sk_buff *skb; | |
198 | ||
199 | skb = skb_get(__skb); | |
200 | ||
201 | if (skb->len >= NLMSG_SPACE(0)) { | |
b529ccf2 | 202 | nlh = nlmsg_hdr(skb); |
7672d0b5 EP |
203 | |
204 | if (nlh->nlmsg_len < sizeof(struct cn_msg) || | |
205 | skb->len < nlh->nlmsg_len || | |
206 | nlh->nlmsg_len > CONNECTOR_MAX_MSG_SIZE) { | |
207 | kfree_skb(skb); | |
6cf92e98 | 208 | return; |
7672d0b5 EP |
209 | } |
210 | ||
00f5e06c LZ |
211 | msg = NLMSG_DATA(nlh); |
212 | err = cn_call_callback(msg, (void (*)(void *))kfree_skb, skb); | |
7672d0b5 EP |
213 | if (err < 0) |
214 | kfree_skb(skb); | |
215 | } | |
7672d0b5 EP |
216 | } |
217 | ||
7672d0b5 EP |
218 | /* |
219 | * Notification routing. | |
220 | * | |
221 | * Gets id and checks if there are notification request for it's idx | |
222 | * and val. If there are such requests notify the listeners with the | |
223 | * given notify event. | |
224 | * | |
225 | */ | |
226 | static void cn_notify(struct cb_id *id, u32 notify_event) | |
227 | { | |
228 | struct cn_ctl_entry *ent; | |
229 | ||
8ed965d6 | 230 | mutex_lock(¬ify_lock); |
7672d0b5 EP |
231 | list_for_each_entry(ent, ¬ify_list, notify_entry) { |
232 | int i; | |
233 | struct cn_notify_req *req; | |
234 | struct cn_ctl_msg *ctl = ent->msg; | |
235 | int idx_found, val_found; | |
236 | ||
237 | idx_found = val_found = 0; | |
238 | ||
239 | req = (struct cn_notify_req *)ctl->data; | |
240 | for (i = 0; i < ctl->idx_notify_num; ++i, ++req) { | |
1a5645bc | 241 | if (id->idx >= req->first && |
7672d0b5 EP |
242 | id->idx < req->first + req->range) { |
243 | idx_found = 1; | |
244 | break; | |
245 | } | |
246 | } | |
247 | ||
248 | for (i = 0; i < ctl->val_notify_num; ++i, ++req) { | |
1a5645bc | 249 | if (id->val >= req->first && |
7672d0b5 EP |
250 | id->val < req->first + req->range) { |
251 | val_found = 1; | |
252 | break; | |
253 | } | |
254 | } | |
255 | ||
256 | if (idx_found && val_found) { | |
257 | struct cn_msg m = { .ack = notify_event, }; | |
258 | ||
259 | memcpy(&m.id, id, sizeof(m.id)); | |
260 | cn_netlink_send(&m, ctl->group, GFP_KERNEL); | |
261 | } | |
262 | } | |
8ed965d6 | 263 | mutex_unlock(¬ify_lock); |
7672d0b5 EP |
264 | } |
265 | ||
266 | /* | |
267 | * Callback add routing - adds callback with given ID and name. | |
268 | * If there is registered callback with the same ID it will not be added. | |
269 | * | |
270 | * May sleep. | |
271 | */ | |
272 | int cn_add_callback(struct cb_id *id, char *name, void (*callback)(void *)) | |
273 | { | |
274 | int err; | |
275 | struct cn_dev *dev = &cdev; | |
7672d0b5 | 276 | |
d6cc7f1a EP |
277 | if (!cn_already_initialized) |
278 | return -EAGAIN; | |
279 | ||
acd042bb EP |
280 | err = cn_queue_add_callback(dev->cbdev, name, id, callback); |
281 | if (err) | |
7672d0b5 | 282 | return err; |
7672d0b5 EP |
283 | |
284 | cn_notify(id, 0); | |
285 | ||
286 | return 0; | |
287 | } | |
deb0e9b2 | 288 | EXPORT_SYMBOL_GPL(cn_add_callback); |
7672d0b5 EP |
289 | |
290 | /* | |
291 | * Callback remove routing - removes callback | |
292 | * with given ID. | |
293 | * If there is no registered callback with given | |
294 | * ID nothing happens. | |
295 | * | |
296 | * May sleep while waiting for reference counter to become zero. | |
297 | */ | |
298 | void cn_del_callback(struct cb_id *id) | |
299 | { | |
300 | struct cn_dev *dev = &cdev; | |
301 | ||
302 | cn_queue_del_callback(dev->cbdev, id); | |
303 | cn_notify(id, 1); | |
304 | } | |
deb0e9b2 | 305 | EXPORT_SYMBOL_GPL(cn_del_callback); |
7672d0b5 EP |
306 | |
307 | /* | |
308 | * Checks two connector's control messages to be the same. | |
309 | * Returns 1 if they are the same or if the first one is corrupted. | |
310 | */ | |
311 | static int cn_ctl_msg_equals(struct cn_ctl_msg *m1, struct cn_ctl_msg *m2) | |
312 | { | |
313 | int i; | |
314 | struct cn_notify_req *req1, *req2; | |
315 | ||
316 | if (m1->idx_notify_num != m2->idx_notify_num) | |
317 | return 0; | |
318 | ||
319 | if (m1->val_notify_num != m2->val_notify_num) | |
320 | return 0; | |
321 | ||
322 | if (m1->len != m2->len) | |
323 | return 0; | |
324 | ||
325 | if ((m1->idx_notify_num + m1->val_notify_num) * sizeof(*req1) != | |
326 | m1->len) | |
327 | return 1; | |
328 | ||
329 | req1 = (struct cn_notify_req *)m1->data; | |
330 | req2 = (struct cn_notify_req *)m2->data; | |
331 | ||
332 | for (i = 0; i < m1->idx_notify_num; ++i) { | |
333 | if (req1->first != req2->first || req1->range != req2->range) | |
334 | return 0; | |
335 | req1++; | |
336 | req2++; | |
337 | } | |
338 | ||
339 | for (i = 0; i < m1->val_notify_num; ++i) { | |
340 | if (req1->first != req2->first || req1->range != req2->range) | |
341 | return 0; | |
342 | req1++; | |
343 | req2++; | |
344 | } | |
345 | ||
346 | return 1; | |
347 | } | |
348 | ||
349 | /* | |
350 | * Main connector device's callback. | |
351 | * | |
352 | * Used for notification of a request's processing. | |
353 | */ | |
354 | static void cn_callback(void *data) | |
355 | { | |
356 | struct cn_msg *msg = data; | |
357 | struct cn_ctl_msg *ctl; | |
358 | struct cn_ctl_entry *ent; | |
359 | u32 size; | |
360 | ||
361 | if (msg->len < sizeof(*ctl)) | |
362 | return; | |
363 | ||
364 | ctl = (struct cn_ctl_msg *)msg->data; | |
365 | ||
366 | size = (sizeof(*ctl) + ((ctl->idx_notify_num + | |
367 | ctl->val_notify_num) * | |
368 | sizeof(struct cn_notify_req))); | |
369 | ||
370 | if (msg->len != size) | |
371 | return; | |
372 | ||
373 | if (ctl->len + sizeof(*ctl) != msg->len) | |
374 | return; | |
375 | ||
376 | /* | |
377 | * Remove notification. | |
378 | */ | |
379 | if (ctl->group == 0) { | |
380 | struct cn_ctl_entry *n; | |
381 | ||
8ed965d6 | 382 | mutex_lock(¬ify_lock); |
7672d0b5 EP |
383 | list_for_each_entry_safe(ent, n, ¬ify_list, notify_entry) { |
384 | if (cn_ctl_msg_equals(ent->msg, ctl)) { | |
385 | list_del(&ent->notify_entry); | |
386 | kfree(ent); | |
387 | } | |
388 | } | |
8ed965d6 | 389 | mutex_unlock(¬ify_lock); |
7672d0b5 EP |
390 | |
391 | return; | |
392 | } | |
393 | ||
394 | size += sizeof(*ent); | |
395 | ||
396 | ent = kzalloc(size, GFP_KERNEL); | |
397 | if (!ent) | |
398 | return; | |
399 | ||
400 | ent->msg = (struct cn_ctl_msg *)(ent + 1); | |
401 | ||
402 | memcpy(ent->msg, ctl, size - sizeof(*ent)); | |
403 | ||
8ed965d6 | 404 | mutex_lock(¬ify_lock); |
7672d0b5 | 405 | list_add(&ent->notify_entry, ¬ify_list); |
8ed965d6 | 406 | mutex_unlock(¬ify_lock); |
7672d0b5 EP |
407 | } |
408 | ||
a0a61a60 LZ |
409 | static int cn_proc_show(struct seq_file *m, void *v) |
410 | { | |
411 | struct cn_queue_dev *dev = cdev.cbdev; | |
412 | struct cn_callback_entry *cbq; | |
413 | ||
414 | seq_printf(m, "Name ID\n"); | |
415 | ||
416 | spin_lock_bh(&dev->queue_lock); | |
417 | ||
418 | list_for_each_entry(cbq, &dev->queue_list, callback_entry) { | |
419 | seq_printf(m, "%-15s %u:%u\n", | |
420 | cbq->id.name, | |
421 | cbq->id.id.idx, | |
422 | cbq->id.id.val); | |
423 | } | |
424 | ||
425 | spin_unlock_bh(&dev->queue_lock); | |
426 | ||
427 | return 0; | |
428 | } | |
429 | ||
430 | static int cn_proc_open(struct inode *inode, struct file *file) | |
431 | { | |
432 | return single_open(file, cn_proc_show, NULL); | |
433 | } | |
434 | ||
435 | static const struct file_operations cn_file_ops = { | |
436 | .owner = THIS_MODULE, | |
437 | .open = cn_proc_open, | |
438 | .read = seq_read, | |
439 | .llseek = seq_lseek, | |
440 | .release = single_release | |
441 | }; | |
442 | ||
d6cc7f1a | 443 | static int __devinit cn_init(void) |
7672d0b5 EP |
444 | { |
445 | struct cn_dev *dev = &cdev; | |
446 | int err; | |
447 | ||
cd40b7d3 | 448 | dev->input = cn_rx_skb; |
7672d0b5 EP |
449 | dev->id.idx = cn_idx; |
450 | dev->id.val = cn_val; | |
451 | ||
b4b51029 | 452 | dev->nls = netlink_kernel_create(&init_net, NETLINK_CONNECTOR, |
7672d0b5 | 453 | CN_NETLINK_USERS + 0xf, |
af65bdfc | 454 | dev->input, NULL, THIS_MODULE); |
7672d0b5 EP |
455 | if (!dev->nls) |
456 | return -EIO; | |
457 | ||
458 | dev->cbdev = cn_queue_alloc_dev("cqueue", dev->nls); | |
459 | if (!dev->cbdev) { | |
b7c6ba6e | 460 | netlink_kernel_release(dev->nls); |
7672d0b5 EP |
461 | return -EINVAL; |
462 | } | |
1a5645bc | 463 | |
d6cc7f1a | 464 | cn_already_initialized = 1; |
7672d0b5 EP |
465 | |
466 | err = cn_add_callback(&dev->id, "connector", &cn_callback); | |
467 | if (err) { | |
d6cc7f1a | 468 | cn_already_initialized = 0; |
7672d0b5 | 469 | cn_queue_free_dev(dev->cbdev); |
b7c6ba6e | 470 | netlink_kernel_release(dev->nls); |
7672d0b5 EP |
471 | return -EINVAL; |
472 | } | |
473 | ||
a0a61a60 LZ |
474 | proc_net_fops_create(&init_net, "connector", S_IRUGO, &cn_file_ops); |
475 | ||
7672d0b5 EP |
476 | return 0; |
477 | } | |
478 | ||
d6cc7f1a | 479 | static void __devexit cn_fini(void) |
7672d0b5 EP |
480 | { |
481 | struct cn_dev *dev = &cdev; | |
482 | ||
483 | cn_already_initialized = 0; | |
484 | ||
a0a61a60 LZ |
485 | proc_net_remove(&init_net, "connector"); |
486 | ||
7672d0b5 EP |
487 | cn_del_callback(&dev->id); |
488 | cn_queue_free_dev(dev->cbdev); | |
b7c6ba6e | 489 | netlink_kernel_release(dev->nls); |
7672d0b5 EP |
490 | } |
491 | ||
d6cc7f1a | 492 | subsys_initcall(cn_init); |
7672d0b5 | 493 | module_exit(cn_fini); |