xref: /linux/net/nfc/netlink.c (revision 424f0750edd5af866f80f5e65998e0610503cb5c) 
1 /*
2  * Copyright (C) 2011 Instituto Nokia de Tecnologia
3  *
4  * Authors:
5  *    Lauro Ramos Venancio <lauro.venancio@openbossa.org>
6  *    Aloisio Almeida Jr <aloisio.almeida@openbossa.org>
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License as published by
10  * the Free Software Foundation; either version 2 of the License, or
11  * (at your option) any later version.
12  *
13  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16  * GNU General Public License for more details.
17  *
18  * You should have received a copy of the GNU General Public License
19  * along with this program; if not, write to the
20  * Free Software Foundation, Inc.,
21  * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
22  */
23 
24 #include <net/genetlink.h>
25 #include <linux/nfc.h>
26 #include <linux/slab.h>
27 
28 #include "nfc.h"
29 
30 static struct genl_multicast_group nfc_genl_event_mcgrp = {
31 	.name = NFC_GENL_MCAST_EVENT_NAME,
32 };
33 
34 struct genl_family nfc_genl_family = {
35 	.id = GENL_ID_GENERATE,
36 	.hdrsize = 0,
37 	.name = NFC_GENL_NAME,
38 	.version = NFC_GENL_VERSION,
39 	.maxattr = NFC_ATTR_MAX,
40 };
41 
42 static const struct nla_policy nfc_genl_policy[NFC_ATTR_MAX + 1] = {
43 	[NFC_ATTR_DEVICE_INDEX] = { .type = NLA_U32 },
44 	[NFC_ATTR_DEVICE_NAME] = { .type = NLA_STRING,
45 				.len = NFC_DEVICE_NAME_MAXSIZE },
46 	[NFC_ATTR_PROTOCOLS] = { .type = NLA_U32 },
47 };
48 
49 static int nfc_genl_send_target(struct sk_buff *msg, struct nfc_target *target,
50 					struct netlink_callback *cb, int flags)
51 {
52 	void *hdr;
53 
54 	nfc_dbg("entry");
55 
56 	hdr = genlmsg_put(msg, NETLINK_CB(cb->skb).pid, cb->nlh->nlmsg_seq,
57 				&nfc_genl_family, flags, NFC_CMD_GET_TARGET);
58 	if (!hdr)
59 		return -EMSGSIZE;
60 
61 	genl_dump_check_consistent(cb, hdr, &nfc_genl_family);
62 
63 	NLA_PUT_U32(msg, NFC_ATTR_TARGET_INDEX, target->idx);
64 	NLA_PUT_U32(msg, NFC_ATTR_PROTOCOLS,
65 				target->supported_protocols);
66 	NLA_PUT_U16(msg, NFC_ATTR_TARGET_SENS_RES, target->sens_res);
67 	NLA_PUT_U8(msg, NFC_ATTR_TARGET_SEL_RES, target->sel_res);
68 
69 	return genlmsg_end(msg, hdr);
70 
71 nla_put_failure:
72 	genlmsg_cancel(msg, hdr);
73 	return -EMSGSIZE;
74 }
75 
76 static struct nfc_dev *__get_device_from_cb(struct netlink_callback *cb)
77 {
78 	struct nfc_dev *dev;
79 	int rc;
80 	u32 idx;
81 
82 	rc = nlmsg_parse(cb->nlh, GENL_HDRLEN + nfc_genl_family.hdrsize,
83 						nfc_genl_family.attrbuf,
84 						nfc_genl_family.maxattr,
85 						nfc_genl_policy);
86 	if (rc < 0)
87 		return ERR_PTR(rc);
88 
89 	if (!nfc_genl_family.attrbuf[NFC_ATTR_DEVICE_INDEX])
90 		return ERR_PTR(-EINVAL);
91 
92 	idx = nla_get_u32(nfc_genl_family.attrbuf[NFC_ATTR_DEVICE_INDEX]);
93 
94 	dev = nfc_get_device(idx);
95 	if (!dev)
96 		return ERR_PTR(-ENODEV);
97 
98 	return dev;
99 }
100 
101 static int nfc_genl_dump_targets(struct sk_buff *skb,
102 				struct netlink_callback *cb)
103 {
104 	int i = cb->args[0];
105 	struct nfc_dev *dev = (struct nfc_dev *) cb->args[1];
106 	int rc;
107 
108 	nfc_dbg("entry");
109 
110 	if (!dev) {
111 		dev = __get_device_from_cb(cb);
112 		if (IS_ERR(dev))
113 			return PTR_ERR(dev);
114 
115 		cb->args[1] = (long) dev;
116 	}
117 
118 	spin_lock_bh(&dev->targets_lock);
119 
120 	cb->seq = dev->targets_generation;
121 
122 	while (i < dev->n_targets) {
123 		rc = nfc_genl_send_target(skb, &dev->targets[i], cb,
124 								NLM_F_MULTI);
125 		if (rc < 0)
126 			break;
127 
128 		i++;
129 	}
130 
131 	spin_unlock_bh(&dev->targets_lock);
132 
133 	cb->args[0] = i;
134 
135 	return skb->len;
136 }
137 
138 static int nfc_genl_dump_targets_done(struct netlink_callback *cb)
139 {
140 	struct nfc_dev *dev = (struct nfc_dev *) cb->args[1];
141 
142 	nfc_dbg("entry");
143 
144 	if (dev)
145 		nfc_put_device(dev);
146 
147 	return 0;
148 }
149 
150 int nfc_genl_targets_found(struct nfc_dev *dev)
151 {
152 	struct sk_buff *msg;
153 	void *hdr;
154 
155 	nfc_dbg("entry");
156 
157 	dev->genl_data.poll_req_pid = 0;
158 
159 	msg = nlmsg_new(NLMSG_GOODSIZE, GFP_ATOMIC);
160 	if (!msg)
161 		return -ENOMEM;
162 
163 	hdr = genlmsg_put(msg, 0, 0, &nfc_genl_family, 0,
164 				NFC_EVENT_TARGETS_FOUND);
165 	if (!hdr)
166 		goto free_msg;
167 
168 	NLA_PUT_U32(msg, NFC_ATTR_DEVICE_INDEX, dev->idx);
169 
170 	genlmsg_end(msg, hdr);
171 
172 	return genlmsg_multicast(msg, 0, nfc_genl_event_mcgrp.id, GFP_ATOMIC);
173 
174 nla_put_failure:
175 	genlmsg_cancel(msg, hdr);
176 free_msg:
177 	nlmsg_free(msg);
178 	return -EMSGSIZE;
179 }
180 
181 int nfc_genl_device_added(struct nfc_dev *dev)
182 {
183 	struct sk_buff *msg;
184 	void *hdr;
185 
186 	nfc_dbg("entry");
187 
188 	msg = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
189 	if (!msg)
190 		return -ENOMEM;
191 
192 	hdr = genlmsg_put(msg, 0, 0, &nfc_genl_family, 0,
193 				NFC_EVENT_DEVICE_ADDED);
194 	if (!hdr)
195 		goto free_msg;
196 
197 	NLA_PUT_STRING(msg, NFC_ATTR_DEVICE_NAME, nfc_device_name(dev));
198 	NLA_PUT_U32(msg, NFC_ATTR_DEVICE_INDEX, dev->idx);
199 	NLA_PUT_U32(msg, NFC_ATTR_PROTOCOLS, dev->supported_protocols);
200 
201 	genlmsg_end(msg, hdr);
202 
203 	genlmsg_multicast(msg, 0, nfc_genl_event_mcgrp.id, GFP_KERNEL);
204 
205 	return 0;
206 
207 nla_put_failure:
208 	genlmsg_cancel(msg, hdr);
209 free_msg:
210 	nlmsg_free(msg);
211 	return -EMSGSIZE;
212 }
213 
214 int nfc_genl_device_removed(struct nfc_dev *dev)
215 {
216 	struct sk_buff *msg;
217 	void *hdr;
218 
219 	nfc_dbg("entry");
220 
221 	msg = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
222 	if (!msg)
223 		return -ENOMEM;
224 
225 	hdr = genlmsg_put(msg, 0, 0, &nfc_genl_family, 0,
226 				NFC_EVENT_DEVICE_REMOVED);
227 	if (!hdr)
228 		goto free_msg;
229 
230 	NLA_PUT_U32(msg, NFC_ATTR_DEVICE_INDEX, dev->idx);
231 
232 	genlmsg_end(msg, hdr);
233 
234 	genlmsg_multicast(msg, 0, nfc_genl_event_mcgrp.id, GFP_KERNEL);
235 
236 	return 0;
237 
238 nla_put_failure:
239 	genlmsg_cancel(msg, hdr);
240 free_msg:
241 	nlmsg_free(msg);
242 	return -EMSGSIZE;
243 }
244 
245 static int nfc_genl_send_device(struct sk_buff *msg, struct nfc_dev *dev,
246 						u32 pid, u32 seq,
247 						struct netlink_callback *cb,
248 						int flags)
249 {
250 	void *hdr;
251 
252 	nfc_dbg("entry");
253 
254 	hdr = genlmsg_put(msg, pid, seq, &nfc_genl_family, flags,
255 							NFC_CMD_GET_DEVICE);
256 	if (!hdr)
257 		return -EMSGSIZE;
258 
259 	if (cb)
260 		genl_dump_check_consistent(cb, hdr, &nfc_genl_family);
261 
262 	NLA_PUT_STRING(msg, NFC_ATTR_DEVICE_NAME, nfc_device_name(dev));
263 	NLA_PUT_U32(msg, NFC_ATTR_DEVICE_INDEX, dev->idx);
264 	NLA_PUT_U32(msg, NFC_ATTR_PROTOCOLS, dev->supported_protocols);
265 
266 	return genlmsg_end(msg, hdr);
267 
268 nla_put_failure:
269 	genlmsg_cancel(msg, hdr);
270 	return -EMSGSIZE;
271 }
272 
273 static int nfc_genl_dump_devices(struct sk_buff *skb,
274 				struct netlink_callback *cb)
275 {
276 	struct class_dev_iter *iter = (struct class_dev_iter *) cb->args[0];
277 	struct nfc_dev *dev = (struct nfc_dev *) cb->args[1];
278 	bool first_call = false;
279 
280 	nfc_dbg("entry");
281 
282 	if (!iter) {
283 		first_call = true;
284 		iter = kmalloc(sizeof(struct class_dev_iter), GFP_KERNEL);
285 		if (!iter)
286 			return -ENOMEM;
287 		cb->args[0] = (long) iter;
288 	}
289 
290 	mutex_lock(&nfc_devlist_mutex);
291 
292 	cb->seq = nfc_devlist_generation;
293 
294 	if (first_call) {
295 		nfc_device_iter_init(iter);
296 		dev = nfc_device_iter_next(iter);
297 	}
298 
299 	while (dev) {
300 		int rc;
301 
302 		rc = nfc_genl_send_device(skb, dev, NETLINK_CB(cb->skb).pid,
303 							cb->nlh->nlmsg_seq,
304 							cb, NLM_F_MULTI);
305 		if (rc < 0)
306 			break;
307 
308 		dev = nfc_device_iter_next(iter);
309 	}
310 
311 	mutex_unlock(&nfc_devlist_mutex);
312 
313 	cb->args[1] = (long) dev;
314 
315 	return skb->len;
316 }
317 
318 static int nfc_genl_dump_devices_done(struct netlink_callback *cb)
319 {
320 	struct class_dev_iter *iter = (struct class_dev_iter *) cb->args[0];
321 
322 	nfc_dbg("entry");
323 
324 	nfc_device_iter_exit(iter);
325 	kfree(iter);
326 
327 	return 0;
328 }
329 
330 static int nfc_genl_get_device(struct sk_buff *skb, struct genl_info *info)
331 {
332 	struct sk_buff *msg;
333 	struct nfc_dev *dev;
334 	u32 idx;
335 	int rc = -ENOBUFS;
336 
337 	nfc_dbg("entry");
338 
339 	if (!info->attrs[NFC_ATTR_DEVICE_INDEX])
340 		return -EINVAL;
341 
342 	idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]);
343 
344 	dev = nfc_get_device(idx);
345 	if (!dev)
346 		return -ENODEV;
347 
348 	msg = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
349 	if (!msg) {
350 		rc = -ENOMEM;
351 		goto out_putdev;
352 	}
353 
354 	rc = nfc_genl_send_device(msg, dev, info->snd_pid, info->snd_seq,
355 								NULL, 0);
356 	if (rc < 0)
357 		goto out_free;
358 
359 	nfc_put_device(dev);
360 
361 	return genlmsg_reply(msg, info);
362 
363 out_free:
364 	nlmsg_free(msg);
365 out_putdev:
366 	nfc_put_device(dev);
367 	return rc;
368 }
369 
370 static int nfc_genl_dev_up(struct sk_buff *skb, struct genl_info *info)
371 {
372 	struct nfc_dev *dev;
373 	int rc;
374 	u32 idx;
375 
376 	nfc_dbg("entry");
377 
378 	if (!info->attrs[NFC_ATTR_DEVICE_INDEX])
379 		return -EINVAL;
380 
381 	idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]);
382 
383 	dev = nfc_get_device(idx);
384 	if (!dev)
385 		return -ENODEV;
386 
387 	rc = nfc_dev_up(dev);
388 
389 	nfc_put_device(dev);
390 	return rc;
391 }
392 
393 static int nfc_genl_dev_down(struct sk_buff *skb, struct genl_info *info)
394 {
395 	struct nfc_dev *dev;
396 	int rc;
397 	u32 idx;
398 
399 	nfc_dbg("entry");
400 
401 	if (!info->attrs[NFC_ATTR_DEVICE_INDEX])
402 		return -EINVAL;
403 
404 	idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]);
405 
406 	dev = nfc_get_device(idx);
407 	if (!dev)
408 		return -ENODEV;
409 
410 	rc = nfc_dev_down(dev);
411 
412 	nfc_put_device(dev);
413 	return rc;
414 }
415 
416 static int nfc_genl_start_poll(struct sk_buff *skb, struct genl_info *info)
417 {
418 	struct nfc_dev *dev;
419 	int rc;
420 	u32 idx;
421 	u32 protocols;
422 
423 	nfc_dbg("entry");
424 
425 	if (!info->attrs[NFC_ATTR_DEVICE_INDEX] ||
426 		!info->attrs[NFC_ATTR_PROTOCOLS])
427 		return -EINVAL;
428 
429 	idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]);
430 	protocols = nla_get_u32(info->attrs[NFC_ATTR_PROTOCOLS]);
431 
432 	dev = nfc_get_device(idx);
433 	if (!dev)
434 		return -ENODEV;
435 
436 	mutex_lock(&dev->genl_data.genl_data_mutex);
437 
438 	rc = nfc_start_poll(dev, protocols);
439 	if (!rc)
440 		dev->genl_data.poll_req_pid = info->snd_pid;
441 
442 	mutex_unlock(&dev->genl_data.genl_data_mutex);
443 
444 	nfc_put_device(dev);
445 	return rc;
446 }
447 
448 static int nfc_genl_stop_poll(struct sk_buff *skb, struct genl_info *info)
449 {
450 	struct nfc_dev *dev;
451 	int rc;
452 	u32 idx;
453 
454 	nfc_dbg("entry");
455 
456 	if (!info->attrs[NFC_ATTR_DEVICE_INDEX])
457 		return -EINVAL;
458 
459 	idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]);
460 
461 	dev = nfc_get_device(idx);
462 	if (!dev)
463 		return -ENODEV;
464 
465 	mutex_lock(&dev->genl_data.genl_data_mutex);
466 
467 	if (dev->genl_data.poll_req_pid != info->snd_pid) {
468 		rc = -EBUSY;
469 		goto out;
470 	}
471 
472 	rc = nfc_stop_poll(dev);
473 	dev->genl_data.poll_req_pid = 0;
474 
475 out:
476 	mutex_unlock(&dev->genl_data.genl_data_mutex);
477 	nfc_put_device(dev);
478 	return rc;
479 }
480 
481 static struct genl_ops nfc_genl_ops[] = {
482 	{
483 		.cmd = NFC_CMD_GET_DEVICE,
484 		.doit = nfc_genl_get_device,
485 		.dumpit = nfc_genl_dump_devices,
486 		.done = nfc_genl_dump_devices_done,
487 		.policy = nfc_genl_policy,
488 	},
489 	{
490 		.cmd = NFC_CMD_DEV_UP,
491 		.doit = nfc_genl_dev_up,
492 		.policy = nfc_genl_policy,
493 	},
494 	{
495 		.cmd = NFC_CMD_DEV_DOWN,
496 		.doit = nfc_genl_dev_down,
497 		.policy = nfc_genl_policy,
498 	},
499 	{
500 		.cmd = NFC_CMD_START_POLL,
501 		.doit = nfc_genl_start_poll,
502 		.policy = nfc_genl_policy,
503 	},
504 	{
505 		.cmd = NFC_CMD_STOP_POLL,
506 		.doit = nfc_genl_stop_poll,
507 		.policy = nfc_genl_policy,
508 	},
509 	{
510 		.cmd = NFC_CMD_GET_TARGET,
511 		.dumpit = nfc_genl_dump_targets,
512 		.done = nfc_genl_dump_targets_done,
513 		.policy = nfc_genl_policy,
514 	},
515 };
516 
517 static int nfc_genl_rcv_nl_event(struct notifier_block *this,
518 						unsigned long event, void *ptr)
519 {
520 	struct netlink_notify *n = ptr;
521 	struct class_dev_iter iter;
522 	struct nfc_dev *dev;
523 
524 	if (event != NETLINK_URELEASE || n->protocol != NETLINK_GENERIC)
525 		goto out;
526 
527 	nfc_dbg("NETLINK_URELEASE event from id %d", n->pid);
528 
529 	nfc_device_iter_init(&iter);
530 	dev = nfc_device_iter_next(&iter);
531 
532 	while (dev) {
533 		mutex_lock(&dev->genl_data.genl_data_mutex);
534 		if (dev->genl_data.poll_req_pid == n->pid) {
535 			nfc_stop_poll(dev);
536 			dev->genl_data.poll_req_pid = 0;
537 		}
538 		mutex_unlock(&dev->genl_data.genl_data_mutex);
539 		dev = nfc_device_iter_next(&iter);
540 	}
541 
542 	nfc_device_iter_exit(&iter);
543 
544 out:
545 	return NOTIFY_DONE;
546 }
547 
548 void nfc_genl_data_init(struct nfc_genl_data *genl_data)
549 {
550 	genl_data->poll_req_pid = 0;
551 	mutex_init(&genl_data->genl_data_mutex);
552 }
553 
554 void nfc_genl_data_exit(struct nfc_genl_data *genl_data)
555 {
556 	mutex_destroy(&genl_data->genl_data_mutex);
557 }
558 
559 static struct notifier_block nl_notifier = {
560 	.notifier_call  = nfc_genl_rcv_nl_event,
561 };
562 
563 /**
564  * nfc_genl_init() - Initialize netlink interface
565  *
566  * This initialization function registers the nfc netlink family.
567  */
568 int __init nfc_genl_init(void)
569 {
570 	int rc;
571 
572 	rc = genl_register_family_with_ops(&nfc_genl_family, nfc_genl_ops,
573 					ARRAY_SIZE(nfc_genl_ops));
574 	if (rc)
575 		return rc;
576 
577 	rc = genl_register_mc_group(&nfc_genl_family, &nfc_genl_event_mcgrp);
578 
579 	netlink_register_notifier(&nl_notifier);
580 
581 	return rc;
582 }
583 
584 /**
585  * nfc_genl_exit() - Deinitialize netlink interface
586  *
587  * This exit function unregisters the nfc netlink family.
588  */
589 void nfc_genl_exit(void)
590 {
591 	netlink_unregister_notifier(&nl_notifier);
592 	genl_unregister_family(&nfc_genl_family);
593 }
594