blob: 505677fb3157dce217f4b675bfb559fffcbfc472 [file] [log] [blame]
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -07001/*
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>
29
30#include <net/sock.h>
31
32MODULE_LICENSE("GPL");
33MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>");
34MODULE_DESCRIPTION("Generic userspace <-> kernelspace connector.");
35
36static u32 cn_idx = CN_IDX_CONNECTOR;
37static u32 cn_val = CN_VAL_CONNECTOR;
38
39module_param(cn_idx, uint, 0);
40module_param(cn_val, uint, 0);
41MODULE_PARM_DESC(cn_idx, "Connector's main device idx.");
42MODULE_PARM_DESC(cn_val, "Connector's main device val.");
43
44static DECLARE_MUTEX(notify_lock);
45static LIST_HEAD(notify_list);
46
47static struct cn_dev cdev;
48
49int cn_already_initialized = 0;
50
51/*
52 * msg->seq and msg->ack are used to determine message genealogy.
53 * When someone sends message it puts there locally unique sequence
54 * and random acknowledge numbers. Sequence number may be copied into
55 * nlmsghdr->nlmsg_seq too.
56 *
57 * Sequence number is incremented with each message to be sent.
58 *
59 * If we expect reply to our message then the sequence number in
60 * received message MUST be the same as in original message, and
61 * acknowledge number MUST be the same + 1.
62 *
63 * If we receive a message and its sequence number is not equal to the
64 * one we are expecting then it is a new message.
65 *
66 * If we receive a message and its sequence number is the same as one
67 * we are expecting but it's acknowledgement number is not equal to
68 * the acknowledgement number in the original message + 1, then it is
69 * a new message.
70 *
71 */
Al Virodd0fc662005-10-07 07:46:04 +010072int cn_netlink_send(struct cn_msg *msg, u32 __group, gfp_t gfp_mask)
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -070073{
74 struct cn_callback_entry *__cbq;
75 unsigned int size;
76 struct sk_buff *skb;
77 struct nlmsghdr *nlh;
78 struct cn_msg *data;
79 struct cn_dev *dev = &cdev;
80 u32 group = 0;
81 int found = 0;
82
83 if (!__group) {
84 spin_lock_bh(&dev->cbdev->queue_lock);
85 list_for_each_entry(__cbq, &dev->cbdev->queue_list,
86 callback_entry) {
Evgeniy Polyakovacd042b2005-09-26 15:06:50 -070087 if (cn_cb_equal(&__cbq->id.id, &msg->id)) {
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -070088 found = 1;
89 group = __cbq->group;
90 }
91 }
92 spin_unlock_bh(&dev->cbdev->queue_lock);
93
94 if (!found)
95 return -ENODEV;
96 } else {
97 group = __group;
98 }
99
100 size = NLMSG_SPACE(sizeof(*msg) + msg->len);
101
102 skb = alloc_skb(size, gfp_mask);
103 if (!skb)
104 return -ENOMEM;
105
106 nlh = NLMSG_PUT(skb, 0, msg->seq, NLMSG_DONE, size - sizeof(*nlh));
107
108 data = NLMSG_DATA(nlh);
109
110 memcpy(data, msg, sizeof(*data) + msg->len);
111
112 NETLINK_CB(skb).dst_group = group;
113
114 netlink_broadcast(dev->nls, skb, 0, group, gfp_mask);
115
116 return 0;
117
118nlmsg_failure:
119 kfree_skb(skb);
120 return -EINVAL;
121}
122
123/*
124 * Callback helper - queues work and setup destructor for given data.
125 */
126static int cn_call_callback(struct cn_msg *msg, void (*destruct_data)(void *), void *data)
127{
128 struct cn_callback_entry *__cbq;
129 struct cn_dev *dev = &cdev;
Evgeniy Polyakovacd042b2005-09-26 15:06:50 -0700130 int err = -ENODEV;
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700131
132 spin_lock_bh(&dev->cbdev->queue_lock);
133 list_for_each_entry(__cbq, &dev->cbdev->queue_list, callback_entry) {
Evgeniy Polyakovacd042b2005-09-26 15:06:50 -0700134 if (cn_cb_equal(&__cbq->id.id, &msg->id)) {
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700135 if (likely(!test_bit(0, &__cbq->work.pending) &&
Evgeniy Polyakovacd042b2005-09-26 15:06:50 -0700136 __cbq->data.ddata == NULL)) {
137 __cbq->data.callback_priv = msg;
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700138
Evgeniy Polyakovacd042b2005-09-26 15:06:50 -0700139 __cbq->data.ddata = data;
140 __cbq->data.destruct_data = destruct_data;
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700141
142 if (queue_work(dev->cbdev->cn_queue,
143 &__cbq->work))
Evgeniy Polyakovacd042b2005-09-26 15:06:50 -0700144 err = 0;
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700145 } else {
Evgeniy Polyakovacd042b2005-09-26 15:06:50 -0700146 struct work_struct *w;
147 struct cn_callback_data *d;
148
149 w = kzalloc(sizeof(*w) + sizeof(*d), GFP_ATOMIC);
150 if (w) {
151 d = (struct cn_callback_data *)(w+1);
152
153 d->callback_priv = msg;
154 d->callback = __cbq->data.callback;
155 d->ddata = data;
156 d->destruct_data = destruct_data;
157 d->free = w;
158
159 INIT_LIST_HEAD(&w->entry);
160 w->pending = 0;
161 w->func = &cn_queue_wrapper;
162 w->data = d;
163 init_timer(&w->timer);
164
165 if (queue_work(dev->cbdev->cn_queue, w))
166 err = 0;
167 else {
168 kfree(w);
169 err = -EINVAL;
170 }
171 } else
172 err = -ENOMEM;
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700173 }
174 break;
175 }
176 }
177 spin_unlock_bh(&dev->cbdev->queue_lock);
178
Evgeniy Polyakovacd042b2005-09-26 15:06:50 -0700179 return err;
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700180}
181
182/*
183 * Skb receive helper - checks skb and msg size and calls callback
184 * helper.
185 */
186static int __cn_rx_skb(struct sk_buff *skb, struct nlmsghdr *nlh)
187{
188 u32 pid, uid, seq, group;
189 struct cn_msg *msg;
190
191 pid = NETLINK_CREDS(skb)->pid;
192 uid = NETLINK_CREDS(skb)->uid;
193 seq = nlh->nlmsg_seq;
194 group = NETLINK_CB((skb)).dst_group;
195 msg = NLMSG_DATA(nlh);
196
197 return cn_call_callback(msg, (void (*)(void *))kfree_skb, skb);
198}
199
200/*
201 * Main netlink receiving function.
202 *
203 * It checks skb and netlink header sizes and calls the skb receive
204 * helper with a shared skb.
205 */
206static void cn_rx_skb(struct sk_buff *__skb)
207{
208 struct nlmsghdr *nlh;
209 u32 len;
210 int err;
211 struct sk_buff *skb;
212
213 skb = skb_get(__skb);
214
215 if (skb->len >= NLMSG_SPACE(0)) {
216 nlh = (struct nlmsghdr *)skb->data;
217
218 if (nlh->nlmsg_len < sizeof(struct cn_msg) ||
219 skb->len < nlh->nlmsg_len ||
220 nlh->nlmsg_len > CONNECTOR_MAX_MSG_SIZE) {
221 kfree_skb(skb);
222 goto out;
223 }
224
225 len = NLMSG_ALIGN(nlh->nlmsg_len);
226 if (len > skb->len)
227 len = skb->len;
228
229 err = __cn_rx_skb(skb, nlh);
230 if (err < 0)
231 kfree_skb(skb);
232 }
233
234out:
235 kfree_skb(__skb);
236}
237
238/*
239 * Netlink socket input callback - dequeues the skbs and calls the
240 * main netlink receiving function.
241 */
242static void cn_input(struct sock *sk, int len)
243{
244 struct sk_buff *skb;
245
246 while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL)
247 cn_rx_skb(skb);
248}
249
250/*
251 * Notification routing.
252 *
253 * Gets id and checks if there are notification request for it's idx
254 * and val. If there are such requests notify the listeners with the
255 * given notify event.
256 *
257 */
258static void cn_notify(struct cb_id *id, u32 notify_event)
259{
260 struct cn_ctl_entry *ent;
261
262 down(&notify_lock);
263 list_for_each_entry(ent, &notify_list, notify_entry) {
264 int i;
265 struct cn_notify_req *req;
266 struct cn_ctl_msg *ctl = ent->msg;
267 int idx_found, val_found;
268
269 idx_found = val_found = 0;
270
271 req = (struct cn_notify_req *)ctl->data;
272 for (i = 0; i < ctl->idx_notify_num; ++i, ++req) {
273 if (id->idx >= req->first &&
274 id->idx < req->first + req->range) {
275 idx_found = 1;
276 break;
277 }
278 }
279
280 for (i = 0; i < ctl->val_notify_num; ++i, ++req) {
281 if (id->val >= req->first &&
282 id->val < req->first + req->range) {
283 val_found = 1;
284 break;
285 }
286 }
287
288 if (idx_found && val_found) {
289 struct cn_msg m = { .ack = notify_event, };
290
291 memcpy(&m.id, id, sizeof(m.id));
292 cn_netlink_send(&m, ctl->group, GFP_KERNEL);
293 }
294 }
295 up(&notify_lock);
296}
297
298/*
299 * Callback add routing - adds callback with given ID and name.
300 * If there is registered callback with the same ID it will not be added.
301 *
302 * May sleep.
303 */
304int cn_add_callback(struct cb_id *id, char *name, void (*callback)(void *))
305{
306 int err;
307 struct cn_dev *dev = &cdev;
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700308
Evgeniy Polyakovacd042b2005-09-26 15:06:50 -0700309 err = cn_queue_add_callback(dev->cbdev, name, id, callback);
310 if (err)
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700311 return err;
Evgeniy Polyakov7672d0b2005-09-11 19:15:07 -0700312
313 cn_notify(id, 0);
314
315 return 0;
316}
317
318/*
319 * Callback remove routing - removes callback
320 * with given ID.
321 * If there is no registered callback with given
322 * ID nothing happens.
323 *
324 * May sleep while waiting for reference counter to become zero.
325 */
326void cn_del_callback(struct cb_id *id)
327{
328 struct cn_dev *dev = &cdev;
329
330 cn_queue_del_callback(dev->cbdev, id);
331 cn_notify(id, 1);
332}
333
334/*
335 * Checks two connector's control messages to be the same.
336 * Returns 1 if they are the same or if the first one is corrupted.
337 */
338static int cn_ctl_msg_equals(struct cn_ctl_msg *m1, struct cn_ctl_msg *m2)
339{
340 int i;
341 struct cn_notify_req *req1, *req2;
342
343 if (m1->idx_notify_num != m2->idx_notify_num)
344 return 0;
345
346 if (m1->val_notify_num != m2->val_notify_num)
347 return 0;
348
349 if (m1->len != m2->len)
350 return 0;
351
352 if ((m1->idx_notify_num + m1->val_notify_num) * sizeof(*req1) !=
353 m1->len)
354 return 1;
355
356 req1 = (struct cn_notify_req *)m1->data;
357 req2 = (struct cn_notify_req *)m2->data;
358
359 for (i = 0; i < m1->idx_notify_num; ++i) {
360 if (req1->first != req2->first || req1->range != req2->range)
361 return 0;
362 req1++;
363 req2++;
364 }
365
366 for (i = 0; i < m1->val_notify_num; ++i) {
367 if (req1->first != req2->first || req1->range != req2->range)
368 return 0;
369 req1++;
370 req2++;
371 }
372
373 return 1;
374}
375
376/*
377 * Main connector device's callback.
378 *
379 * Used for notification of a request's processing.
380 */
381static void cn_callback(void *data)
382{
383 struct cn_msg *msg = data;
384 struct cn_ctl_msg *ctl;
385 struct cn_ctl_entry *ent;
386 u32 size;
387
388 if (msg->len < sizeof(*ctl))
389 return;
390
391 ctl = (struct cn_ctl_msg *)msg->data;
392
393 size = (sizeof(*ctl) + ((ctl->idx_notify_num +
394 ctl->val_notify_num) *
395 sizeof(struct cn_notify_req)));
396
397 if (msg->len != size)
398 return;
399
400 if (ctl->len + sizeof(*ctl) != msg->len)
401 return;
402
403 /*
404 * Remove notification.
405 */
406 if (ctl->group == 0) {
407 struct cn_ctl_entry *n;
408
409 down(&notify_lock);
410 list_for_each_entry_safe(ent, n, &notify_list, notify_entry) {
411 if (cn_ctl_msg_equals(ent->msg, ctl)) {
412 list_del(&ent->notify_entry);
413 kfree(ent);
414 }
415 }
416 up(&notify_lock);
417
418 return;
419 }
420
421 size += sizeof(*ent);
422
423 ent = kzalloc(size, GFP_KERNEL);
424 if (!ent)
425 return;
426
427 ent->msg = (struct cn_ctl_msg *)(ent + 1);
428
429 memcpy(ent->msg, ctl, size - sizeof(*ent));
430
431 down(&notify_lock);
432 list_add(&ent->notify_entry, &notify_list);
433 up(&notify_lock);
434}
435
436static int __init cn_init(void)
437{
438 struct cn_dev *dev = &cdev;
439 int err;
440
441 dev->input = cn_input;
442 dev->id.idx = cn_idx;
443 dev->id.val = cn_val;
444
445 dev->nls = netlink_kernel_create(NETLINK_CONNECTOR,
446 CN_NETLINK_USERS + 0xf,
447 dev->input, THIS_MODULE);
448 if (!dev->nls)
449 return -EIO;
450
451 dev->cbdev = cn_queue_alloc_dev("cqueue", dev->nls);
452 if (!dev->cbdev) {
453 if (dev->nls->sk_socket)
454 sock_release(dev->nls->sk_socket);
455 return -EINVAL;
456 }
457
458 err = cn_add_callback(&dev->id, "connector", &cn_callback);
459 if (err) {
460 cn_queue_free_dev(dev->cbdev);
461 if (dev->nls->sk_socket)
462 sock_release(dev->nls->sk_socket);
463 return -EINVAL;
464 }
465
466 cn_already_initialized = 1;
467
468 return 0;
469}
470
471static void __exit cn_fini(void)
472{
473 struct cn_dev *dev = &cdev;
474
475 cn_already_initialized = 0;
476
477 cn_del_callback(&dev->id);
478 cn_queue_free_dev(dev->cbdev);
479 if (dev->nls->sk_socket)
480 sock_release(dev->nls->sk_socket);
481}
482
483module_init(cn_init);
484module_exit(cn_fini);
485
486EXPORT_SYMBOL_GPL(cn_add_callback);
487EXPORT_SYMBOL_GPL(cn_del_callback);
488EXPORT_SYMBOL_GPL(cn_netlink_send);