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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#include <linux/mutex.h>
30#include <linux/proc_fs.h>
31#include <linux/spinlock.h>
32
33#include <net/sock.h>
34
35MODULE_LICENSE("GPL");
36MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>");
37MODULE_DESCRIPTION("Generic userspace <-> kernelspace connector.");
38
39static u32 cn_idx = CN_IDX_CONNECTOR;
40static u32 cn_val = CN_VAL_CONNECTOR;
41
42module_param(cn_idx, uint, 0);
43module_param(cn_val, uint, 0);
44MODULE_PARM_DESC(cn_idx, "Connector's main device idx.");
45MODULE_PARM_DESC(cn_val, "Connector's main device val.");
46
47static DEFINE_MUTEX(notify_lock);
48static LIST_HEAD(notify_list);
49
50static struct cn_dev cdev;
51
52static int cn_already_initialized;
53
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74
75int cn_netlink_send(struct cn_msg *msg, u32 __group, gfp_t gfp_mask)
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) {
90 if (cn_cb_equal(&__cbq->id.id, &msg->id)) {
91 found = 1;
92 group = __cbq->group;
93 break;
94 }
95 }
96 spin_unlock_bh(&dev->cbdev->queue_lock);
97
98 if (!found)
99 return -ENODEV;
100 } else {
101 group = __group;
102 }
103
104 if (!netlink_has_listeners(dev->nls, group))
105 return -ESRCH;
106
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
121 return netlink_broadcast(dev->nls, skb, 0, group, gfp_mask);
122
123nlmsg_failure:
124 kfree_skb(skb);
125 return -EINVAL;
126}
127EXPORT_SYMBOL_GPL(cn_netlink_send);
128
129
130
131
132static int cn_call_callback(struct sk_buff *skb)
133{
134 struct cn_callback_entry *__cbq, *__new_cbq;
135 struct cn_dev *dev = &cdev;
136 struct cn_msg *msg = NLMSG_DATA(nlmsg_hdr(skb));
137 int err = -ENODEV;
138
139 spin_lock_bh(&dev->cbdev->queue_lock);
140 list_for_each_entry(__cbq, &dev->cbdev->queue_list, callback_entry) {
141 if (cn_cb_equal(&__cbq->id.id, &msg->id)) {
142 if (likely(!work_pending(&__cbq->work) &&
143 __cbq->data.skb == NULL)) {
144 __cbq->data.skb = skb;
145
146 if (queue_cn_work(__cbq, &__cbq->work))
147 err = 0;
148 else
149 err = -EINVAL;
150 } else {
151 struct cn_callback_data *d;
152
153 err = -ENOMEM;
154 __new_cbq = kzalloc(sizeof(struct cn_callback_entry), GFP_ATOMIC);
155 if (__new_cbq) {
156 d = &__new_cbq->data;
157 d->skb = skb;
158 d->callback = __cbq->data.callback;
159 d->free = __new_cbq;
160
161 __new_cbq->pdev = __cbq->pdev;
162
163 INIT_WORK(&__new_cbq->work,
164 &cn_queue_wrapper);
165
166 if (queue_cn_work(__new_cbq,
167 &__new_cbq->work))
168 err = 0;
169 else {
170 kfree(__new_cbq);
171 err = -EINVAL;
172 }
173 }
174 }
175 break;
176 }
177 }
178 spin_unlock_bh(&dev->cbdev->queue_lock);
179
180 return err;
181}
182
183
184
185
186
187
188static void cn_rx_skb(struct sk_buff *__skb)
189{
190 struct nlmsghdr *nlh;
191 int err;
192 struct sk_buff *skb;
193
194 skb = skb_get(__skb);
195
196 if (skb->len >= NLMSG_SPACE(0)) {
197 nlh = nlmsg_hdr(skb);
198
199 if (nlh->nlmsg_len < sizeof(struct cn_msg) ||
200 skb->len < nlh->nlmsg_len ||
201 nlh->nlmsg_len > CONNECTOR_MAX_MSG_SIZE) {
202 kfree_skb(skb);
203 return;
204 }
205
206 err = cn_call_callback(skb);
207 if (err < 0)
208 kfree_skb(skb);
209 }
210}
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219
220static void cn_notify(struct cb_id *id, u32 notify_event)
221{
222 struct cn_ctl_entry *ent;
223
224 mutex_lock(¬ify_lock);
225 list_for_each_entry(ent, ¬ify_list, notify_entry) {
226 int i;
227 struct cn_notify_req *req;
228 struct cn_ctl_msg *ctl = ent->msg;
229 int idx_found, val_found;
230
231 idx_found = val_found = 0;
232
233 req = (struct cn_notify_req *)ctl->data;
234 for (i = 0; i < ctl->idx_notify_num; ++i, ++req) {
235 if (id->idx >= req->first &&
236 id->idx < req->first + req->range) {
237 idx_found = 1;
238 break;
239 }
240 }
241
242 for (i = 0; i < ctl->val_notify_num; ++i, ++req) {
243 if (id->val >= req->first &&
244 id->val < req->first + req->range) {
245 val_found = 1;
246 break;
247 }
248 }
249
250 if (idx_found && val_found) {
251 struct cn_msg m = { .ack = notify_event, };
252
253 memcpy(&m.id, id, sizeof(m.id));
254 cn_netlink_send(&m, ctl->group, GFP_KERNEL);
255 }
256 }
257 mutex_unlock(¬ify_lock);
258}
259
260
261
262
263
264
265
266int cn_add_callback(struct cb_id *id, char *name,
267 void (*callback)(struct cn_msg *, struct netlink_skb_parms *))
268{
269 int err;
270 struct cn_dev *dev = &cdev;
271
272 if (!cn_already_initialized)
273 return -EAGAIN;
274
275 err = cn_queue_add_callback(dev->cbdev, name, id, callback);
276 if (err)
277 return err;
278
279 cn_notify(id, 0);
280
281 return 0;
282}
283EXPORT_SYMBOL_GPL(cn_add_callback);
284
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291
292
293void cn_del_callback(struct cb_id *id)
294{
295 struct cn_dev *dev = &cdev;
296
297 cn_queue_del_callback(dev->cbdev, id);
298 cn_notify(id, 1);
299}
300EXPORT_SYMBOL_GPL(cn_del_callback);
301
302
303
304
305
306static int cn_ctl_msg_equals(struct cn_ctl_msg *m1, struct cn_ctl_msg *m2)
307{
308 int i;
309 struct cn_notify_req *req1, *req2;
310
311 if (m1->idx_notify_num != m2->idx_notify_num)
312 return 0;
313
314 if (m1->val_notify_num != m2->val_notify_num)
315 return 0;
316
317 if (m1->len != m2->len)
318 return 0;
319
320 if ((m1->idx_notify_num + m1->val_notify_num) * sizeof(*req1) !=
321 m1->len)
322 return 1;
323
324 req1 = (struct cn_notify_req *)m1->data;
325 req2 = (struct cn_notify_req *)m2->data;
326
327 for (i = 0; i < m1->idx_notify_num; ++i) {
328 if (req1->first != req2->first || req1->range != req2->range)
329 return 0;
330 req1++;
331 req2++;
332 }
333
334 for (i = 0; i < m1->val_notify_num; ++i) {
335 if (req1->first != req2->first || req1->range != req2->range)
336 return 0;
337 req1++;
338 req2++;
339 }
340
341 return 1;
342}
343
344
345
346
347
348
349static void cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
350{
351 struct cn_ctl_msg *ctl;
352 struct cn_ctl_entry *ent;
353 u32 size;
354
355 if (msg->len < sizeof(*ctl))
356 return;
357
358 ctl = (struct cn_ctl_msg *)msg->data;
359
360 size = (sizeof(*ctl) + ((ctl->idx_notify_num +
361 ctl->val_notify_num) *
362 sizeof(struct cn_notify_req)));
363
364 if (msg->len != size)
365 return;
366
367 if (ctl->len + sizeof(*ctl) != msg->len)
368 return;
369
370
371
372
373 if (ctl->group == 0) {
374 struct cn_ctl_entry *n;
375
376 mutex_lock(¬ify_lock);
377 list_for_each_entry_safe(ent, n, ¬ify_list, notify_entry) {
378 if (cn_ctl_msg_equals(ent->msg, ctl)) {
379 list_del(&ent->notify_entry);
380 kfree(ent);
381 }
382 }
383 mutex_unlock(¬ify_lock);
384
385 return;
386 }
387
388 size += sizeof(*ent);
389
390 ent = kzalloc(size, GFP_KERNEL);
391 if (!ent)
392 return;
393
394 ent->msg = (struct cn_ctl_msg *)(ent + 1);
395
396 memcpy(ent->msg, ctl, size - sizeof(*ent));
397
398 mutex_lock(¬ify_lock);
399 list_add(&ent->notify_entry, ¬ify_list);
400 mutex_unlock(¬ify_lock);
401}
402
403static int cn_proc_show(struct seq_file *m, void *v)
404{
405 struct cn_queue_dev *dev = cdev.cbdev;
406 struct cn_callback_entry *cbq;
407
408 seq_printf(m, "Name ID\n");
409
410 spin_lock_bh(&dev->queue_lock);
411
412 list_for_each_entry(cbq, &dev->queue_list, callback_entry) {
413 seq_printf(m, "%-15s %u:%u\n",
414 cbq->id.name,
415 cbq->id.id.idx,
416 cbq->id.id.val);
417 }
418
419 spin_unlock_bh(&dev->queue_lock);
420
421 return 0;
422}
423
424static int cn_proc_open(struct inode *inode, struct file *file)
425{
426 return single_open(file, cn_proc_show, NULL);
427}
428
429static const struct file_operations cn_file_ops = {
430 .owner = THIS_MODULE,
431 .open = cn_proc_open,
432 .read = seq_read,
433 .llseek = seq_lseek,
434 .release = single_release
435};
436
437static int __devinit cn_init(void)
438{
439 struct cn_dev *dev = &cdev;
440 int err;
441
442 dev->input = cn_rx_skb;
443 dev->id.idx = cn_idx;
444 dev->id.val = cn_val;
445
446 dev->nls = netlink_kernel_create(&init_net, NETLINK_CONNECTOR,
447 CN_NETLINK_USERS + 0xf,
448 dev->input, NULL, THIS_MODULE);
449 if (!dev->nls)
450 return -EIO;
451
452 dev->cbdev = cn_queue_alloc_dev("cqueue", dev->nls);
453 if (!dev->cbdev) {
454 netlink_kernel_release(dev->nls);
455 return -EINVAL;
456 }
457
458 cn_already_initialized = 1;
459
460 err = cn_add_callback(&dev->id, "connector", &cn_callback);
461 if (err) {
462 cn_already_initialized = 0;
463 cn_queue_free_dev(dev->cbdev);
464 netlink_kernel_release(dev->nls);
465 return -EINVAL;
466 }
467
468 proc_net_fops_create(&init_net, "connector", S_IRUGO, &cn_file_ops);
469
470 return 0;
471}
472
473static void __devexit cn_fini(void)
474{
475 struct cn_dev *dev = &cdev;
476
477 cn_already_initialized = 0;
478
479 proc_net_remove(&init_net, "connector");
480
481 cn_del_callback(&dev->id);
482 cn_queue_free_dev(dev->cbdev);
483 netlink_kernel_release(dev->nls);
484}
485
486subsys_initcall(cn_init);
487module_exit(cn_fini);
488