xref: /openbmc/linux/net/nfc/netlink.c (revision 81d67439) 
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_start_poll(struct sk_buff *skb, struct genl_info *info)
371 {
372 	struct nfc_dev *dev;
373 	int rc;
374 	u32 idx;
375 	u32 protocols;
376 
377 	nfc_dbg("entry");
378 
379 	if (!info->attrs[NFC_ATTR_DEVICE_INDEX] ||
380 		!info->attrs[NFC_ATTR_PROTOCOLS])
381 		return -EINVAL;
382 
383 	idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]);
384 	protocols = nla_get_u32(info->attrs[NFC_ATTR_PROTOCOLS]);
385 
386 	dev = nfc_get_device(idx);
387 	if (!dev)
388 		return -ENODEV;
389 
390 	mutex_lock(&dev->genl_data.genl_data_mutex);
391 
392 	rc = nfc_start_poll(dev, protocols);
393 	if (!rc)
394 		dev->genl_data.poll_req_pid = info->snd_pid;
395 
396 	mutex_unlock(&dev->genl_data.genl_data_mutex);
397 
398 	nfc_put_device(dev);
399 	return rc;
400 }
401 
402 static int nfc_genl_stop_poll(struct sk_buff *skb, struct genl_info *info)
403 {
404 	struct nfc_dev *dev;
405 	int rc;
406 	u32 idx;
407 
408 	nfc_dbg("entry");
409 
410 	if (!info->attrs[NFC_ATTR_DEVICE_INDEX])
411 		return -EINVAL;
412 
413 	idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]);
414 
415 	dev = nfc_get_device(idx);
416 	if (!dev)
417 		return -ENODEV;
418 
419 	mutex_lock(&dev->genl_data.genl_data_mutex);
420 
421 	if (dev->genl_data.poll_req_pid != info->snd_pid) {
422 		rc = -EBUSY;
423 		goto out;
424 	}
425 
426 	rc = nfc_stop_poll(dev);
427 	dev->genl_data.poll_req_pid = 0;
428 
429 out:
430 	mutex_unlock(&dev->genl_data.genl_data_mutex);
431 	nfc_put_device(dev);
432 	return rc;
433 }
434 
435 static struct genl_ops nfc_genl_ops[] = {
436 	{
437 		.cmd = NFC_CMD_GET_DEVICE,
438 		.doit = nfc_genl_get_device,
439 		.dumpit = nfc_genl_dump_devices,
440 		.done = nfc_genl_dump_devices_done,
441 		.policy = nfc_genl_policy,
442 	},
443 	{
444 		.cmd = NFC_CMD_START_POLL,
445 		.doit = nfc_genl_start_poll,
446 		.policy = nfc_genl_policy,
447 	},
448 	{
449 		.cmd = NFC_CMD_STOP_POLL,
450 		.doit = nfc_genl_stop_poll,
451 		.policy = nfc_genl_policy,
452 	},
453 	{
454 		.cmd = NFC_CMD_GET_TARGET,
455 		.dumpit = nfc_genl_dump_targets,
456 		.done = nfc_genl_dump_targets_done,
457 		.policy = nfc_genl_policy,
458 	},
459 };
460 
461 static int nfc_genl_rcv_nl_event(struct notifier_block *this,
462 						unsigned long event, void *ptr)
463 {
464 	struct netlink_notify *n = ptr;
465 	struct class_dev_iter iter;
466 	struct nfc_dev *dev;
467 
468 	if (event != NETLINK_URELEASE || n->protocol != NETLINK_GENERIC)
469 		goto out;
470 
471 	nfc_dbg("NETLINK_URELEASE event from id %d", n->pid);
472 
473 	nfc_device_iter_init(&iter);
474 	dev = nfc_device_iter_next(&iter);
475 
476 	while (dev) {
477 		mutex_lock(&dev->genl_data.genl_data_mutex);
478 		if (dev->genl_data.poll_req_pid == n->pid) {
479 			nfc_stop_poll(dev);
480 			dev->genl_data.poll_req_pid = 0;
481 		}
482 		mutex_unlock(&dev->genl_data.genl_data_mutex);
483 		dev = nfc_device_iter_next(&iter);
484 	}
485 
486 	nfc_device_iter_exit(&iter);
487 
488 out:
489 	return NOTIFY_DONE;
490 }
491 
492 void nfc_genl_data_init(struct nfc_genl_data *genl_data)
493 {
494 	genl_data->poll_req_pid = 0;
495 	mutex_init(&genl_data->genl_data_mutex);
496 }
497 
498 void nfc_genl_data_exit(struct nfc_genl_data *genl_data)
499 {
500 	mutex_destroy(&genl_data->genl_data_mutex);
501 }
502 
503 static struct notifier_block nl_notifier = {
504 	.notifier_call  = nfc_genl_rcv_nl_event,
505 };
506 
507 /**
508  * nfc_genl_init() - Initialize netlink interface
509  *
510  * This initialization function registers the nfc netlink family.
511  */
512 int __init nfc_genl_init(void)
513 {
514 	int rc;
515 
516 	rc = genl_register_family_with_ops(&nfc_genl_family, nfc_genl_ops,
517 					ARRAY_SIZE(nfc_genl_ops));
518 	if (rc)
519 		return rc;
520 
521 	rc = genl_register_mc_group(&nfc_genl_family, &nfc_genl_event_mcgrp);
522 
523 	netlink_register_notifier(&nl_notifier);
524 
525 	return rc;
526 }
527 
528 /**
529  * nfc_genl_exit() - Deinitialize netlink interface
530  *
531  * This exit function unregisters the nfc netlink family.
532  */
533 void nfc_genl_exit(void)
534 {
535 	netlink_unregister_notifier(&nl_notifier);
536 	genl_unregister_family(&nfc_genl_family);
537 }
538