xref: /linux/net/bluetooth/cmtp/core.c (revision 2fe05e1139a555ae91f00a812cb9520e7d3022ab) 
1 /*
2    CMTP implementation for Linux Bluetooth stack (BlueZ).
3    Copyright (C) 2002-2003 Marcel Holtmann <marcel@holtmann.org>
4 
5    This program is free software; you can redistribute it and/or modify
6    it under the terms of the GNU General Public License version 2 as
7    published by the Free Software Foundation;
8 
9    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
10    OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
11    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS.
12    IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) AND AUTHOR(S) BE LIABLE FOR ANY
13    CLAIM, OR ANY SPECIAL INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES
14    WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15    ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 
18    ALL LIABILITY, INCLUDING LIABILITY FOR INFRINGEMENT OF ANY PATENTS,
19    COPYRIGHTS, TRADEMARKS OR OTHER RIGHTS, RELATING TO USE OF THIS
20    SOFTWARE IS DISCLAIMED.
21 */
22 
23 #include <linux/module.h>
24 
25 #include <linux/types.h>
26 #include <linux/errno.h>
27 #include <linux/kernel.h>
28 #include <linux/sched.h>
29 #include <linux/slab.h>
30 #include <linux/poll.h>
31 #include <linux/fcntl.h>
32 #include <linux/freezer.h>
33 #include <linux/skbuff.h>
34 #include <linux/socket.h>
35 #include <linux/ioctl.h>
36 #include <linux/file.h>
37 #include <linux/init.h>
38 #include <linux/kthread.h>
39 #include <net/sock.h>
40 
41 #include <linux/isdn/capilli.h>
42 
43 #include <net/bluetooth/bluetooth.h>
44 #include <net/bluetooth/l2cap.h>
45 
46 #include "cmtp.h"
47 
48 #define VERSION "1.0"
49 
50 static DECLARE_RWSEM(cmtp_session_sem);
51 static LIST_HEAD(cmtp_session_list);
52 
53 static struct cmtp_session *__cmtp_get_session(bdaddr_t *bdaddr)
54 {
55 	struct cmtp_session *session;
56 
57 	BT_DBG("");
58 
59 	list_for_each_entry(session, &cmtp_session_list, list)
60 		if (!bacmp(bdaddr, &session->bdaddr))
61 			return session;
62 
63 	return NULL;
64 }
65 
66 static void __cmtp_link_session(struct cmtp_session *session)
67 {
68 	list_add(&session->list, &cmtp_session_list);
69 }
70 
71 static void __cmtp_unlink_session(struct cmtp_session *session)
72 {
73 	list_del(&session->list);
74 }
75 
76 static void __cmtp_copy_session(struct cmtp_session *session, struct cmtp_conninfo *ci)
77 {
78 	u32 valid_flags = BIT(CMTP_LOOPBACK);
79 	memset(ci, 0, sizeof(*ci));
80 	bacpy(&ci->bdaddr, &session->bdaddr);
81 
82 	ci->flags = session->flags & valid_flags;
83 	ci->state = session->state;
84 
85 	ci->num = session->num;
86 }
87 
88 
89 static inline int cmtp_alloc_block_id(struct cmtp_session *session)
90 {
91 	int i, id = -1;
92 
93 	for (i = 0; i < 16; i++)
94 		if (!test_and_set_bit(i, &session->blockids)) {
95 			id = i;
96 			break;
97 		}
98 
99 	return id;
100 }
101 
102 static inline void cmtp_free_block_id(struct cmtp_session *session, int id)
103 {
104 	clear_bit(id, &session->blockids);
105 }
106 
107 static inline void cmtp_add_msgpart(struct cmtp_session *session, int id, const unsigned char *buf, int count)
108 {
109 	struct sk_buff *skb = session->reassembly[id], *nskb;
110 	int size;
111 
112 	BT_DBG("session %p buf %p count %d", session, buf, count);
113 
114 	size = (skb) ? skb->len + count : count;
115 
116 	nskb = alloc_skb(size, GFP_ATOMIC);
117 	if (!nskb) {
118 		BT_ERR("Can't allocate memory for CAPI message");
119 		return;
120 	}
121 
122 	if (skb && (skb->len > 0))
123 		skb_copy_from_linear_data(skb, skb_put(nskb, skb->len), skb->len);
124 
125 	skb_put_data(nskb, buf, count);
126 
127 	session->reassembly[id] = nskb;
128 
129 	kfree_skb(skb);
130 }
131 
132 static inline int cmtp_recv_frame(struct cmtp_session *session, struct sk_buff *skb)
133 {
134 	__u8 hdr, hdrlen, id;
135 	__u16 len;
136 
137 	BT_DBG("session %p skb %p len %d", session, skb, skb->len);
138 
139 	while (skb->len > 0) {
140 		hdr = skb->data[0];
141 
142 		switch (hdr & 0xc0) {
143 		case 0x40:
144 			hdrlen = 2;
145 			len = skb->data[1];
146 			break;
147 		case 0x80:
148 			hdrlen = 3;
149 			len = skb->data[1] | (skb->data[2] << 8);
150 			break;
151 		default:
152 			hdrlen = 1;
153 			len = 0;
154 			break;
155 		}
156 
157 		id = (hdr & 0x3c) >> 2;
158 
159 		BT_DBG("hdr 0x%02x hdrlen %d len %d id %d", hdr, hdrlen, len, id);
160 
161 		if (hdrlen + len > skb->len) {
162 			BT_ERR("Wrong size or header information in CMTP frame");
163 			break;
164 		}
165 
166 		if (len == 0) {
167 			skb_pull(skb, hdrlen);
168 			continue;
169 		}
170 
171 		switch (hdr & 0x03) {
172 		case 0x00:
173 			cmtp_add_msgpart(session, id, skb->data + hdrlen, len);
174 			cmtp_recv_capimsg(session, session->reassembly[id]);
175 			session->reassembly[id] = NULL;
176 			break;
177 		case 0x01:
178 			cmtp_add_msgpart(session, id, skb->data + hdrlen, len);
179 			break;
180 		default:
181 			kfree_skb(session->reassembly[id]);
182 			session->reassembly[id] = NULL;
183 			break;
184 		}
185 
186 		skb_pull(skb, hdrlen + len);
187 	}
188 
189 	kfree_skb(skb);
190 	return 0;
191 }
192 
193 static int cmtp_send_frame(struct cmtp_session *session, unsigned char *data, int len)
194 {
195 	struct socket *sock = session->sock;
196 	struct kvec iv = { data, len };
197 	struct msghdr msg;
198 
199 	BT_DBG("session %p data %p len %d", session, data, len);
200 
201 	if (!len)
202 		return 0;
203 
204 	memset(&msg, 0, sizeof(msg));
205 
206 	return kernel_sendmsg(sock, &msg, &iv, 1, len);
207 }
208 
209 static void cmtp_process_transmit(struct cmtp_session *session)
210 {
211 	struct sk_buff *skb, *nskb;
212 	unsigned char *hdr;
213 	unsigned int size, tail;
214 
215 	BT_DBG("session %p", session);
216 
217 	nskb = alloc_skb(session->mtu, GFP_ATOMIC);
218 	if (!nskb) {
219 		BT_ERR("Can't allocate memory for new frame");
220 		return;
221 	}
222 
223 	while ((skb = skb_dequeue(&session->transmit))) {
224 		struct cmtp_scb *scb = (void *) skb->cb;
225 
226 		tail = session->mtu - nskb->len;
227 		if (tail < 5) {
228 			cmtp_send_frame(session, nskb->data, nskb->len);
229 			skb_trim(nskb, 0);
230 			tail = session->mtu;
231 		}
232 
233 		size = min_t(uint, ((tail < 258) ? (tail - 2) : (tail - 3)), skb->len);
234 
235 		if (scb->id < 0) {
236 			scb->id = cmtp_alloc_block_id(session);
237 			if (scb->id < 0) {
238 				skb_queue_head(&session->transmit, skb);
239 				break;
240 			}
241 		}
242 
243 		if (size < 256) {
244 			hdr = skb_put(nskb, 2);
245 			hdr[0] = 0x40
246 				| ((scb->id << 2) & 0x3c)
247 				| ((skb->len == size) ? 0x00 : 0x01);
248 			hdr[1] = size;
249 		} else {
250 			hdr = skb_put(nskb, 3);
251 			hdr[0] = 0x80
252 				| ((scb->id << 2) & 0x3c)
253 				| ((skb->len == size) ? 0x00 : 0x01);
254 			hdr[1] = size & 0xff;
255 			hdr[2] = size >> 8;
256 		}
257 
258 		skb_copy_from_linear_data(skb, skb_put(nskb, size), size);
259 		skb_pull(skb, size);
260 
261 		if (skb->len > 0) {
262 			skb_queue_head(&session->transmit, skb);
263 		} else {
264 			cmtp_free_block_id(session, scb->id);
265 			if (scb->data) {
266 				cmtp_send_frame(session, nskb->data, nskb->len);
267 				skb_trim(nskb, 0);
268 			}
269 			kfree_skb(skb);
270 		}
271 	}
272 
273 	cmtp_send_frame(session, nskb->data, nskb->len);
274 
275 	kfree_skb(nskb);
276 }
277 
278 static int cmtp_session(void *arg)
279 {
280 	struct cmtp_session *session = arg;
281 	struct sock *sk = session->sock->sk;
282 	struct sk_buff *skb;
283 	DEFINE_WAIT_FUNC(wait, woken_wake_function);
284 
285 	BT_DBG("session %p", session);
286 
287 	set_user_nice(current, -15);
288 
289 	add_wait_queue(sk_sleep(sk), &wait);
290 	while (1) {
291 		/* Ensure session->terminate is updated */
292 		smp_mb__before_atomic();
293 
294 		if (atomic_read(&session->terminate))
295 			break;
296 		if (sk->sk_state != BT_CONNECTED)
297 			break;
298 
299 		while ((skb = skb_dequeue(&sk->sk_receive_queue))) {
300 			skb_orphan(skb);
301 			if (!skb_linearize(skb))
302 				cmtp_recv_frame(session, skb);
303 			else
304 				kfree_skb(skb);
305 		}
306 
307 		cmtp_process_transmit(session);
308 
309 		wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
310 	}
311 	remove_wait_queue(sk_sleep(sk), &wait);
312 
313 	down_write(&cmtp_session_sem);
314 
315 	if (!(session->flags & BIT(CMTP_LOOPBACK)))
316 		cmtp_detach_device(session);
317 
318 	fput(session->sock->file);
319 
320 	__cmtp_unlink_session(session);
321 
322 	up_write(&cmtp_session_sem);
323 
324 	kfree(session);
325 	module_put_and_exit(0);
326 	return 0;
327 }
328 
329 int cmtp_add_connection(struct cmtp_connadd_req *req, struct socket *sock)
330 {
331 	u32 valid_flags = BIT(CMTP_LOOPBACK);
332 	struct cmtp_session *session, *s;
333 	int i, err;
334 
335 	BT_DBG("");
336 
337 	if (!l2cap_is_socket(sock))
338 		return -EBADFD;
339 
340 	if (req->flags & ~valid_flags)
341 		return -EINVAL;
342 
343 	session = kzalloc(sizeof(struct cmtp_session), GFP_KERNEL);
344 	if (!session)
345 		return -ENOMEM;
346 
347 	down_write(&cmtp_session_sem);
348 
349 	s = __cmtp_get_session(&l2cap_pi(sock->sk)->chan->dst);
350 	if (s && s->state == BT_CONNECTED) {
351 		err = -EEXIST;
352 		goto failed;
353 	}
354 
355 	bacpy(&session->bdaddr, &l2cap_pi(sock->sk)->chan->dst);
356 
357 	session->mtu = min_t(uint, l2cap_pi(sock->sk)->chan->omtu,
358 					l2cap_pi(sock->sk)->chan->imtu);
359 
360 	BT_DBG("mtu %d", session->mtu);
361 
362 	sprintf(session->name, "%pMR", &session->bdaddr);
363 
364 	session->sock  = sock;
365 	session->state = BT_CONFIG;
366 
367 	init_waitqueue_head(&session->wait);
368 
369 	session->msgnum = CMTP_INITIAL_MSGNUM;
370 
371 	INIT_LIST_HEAD(&session->applications);
372 
373 	skb_queue_head_init(&session->transmit);
374 
375 	for (i = 0; i < 16; i++)
376 		session->reassembly[i] = NULL;
377 
378 	session->flags = req->flags;
379 
380 	__cmtp_link_session(session);
381 
382 	__module_get(THIS_MODULE);
383 	session->task = kthread_run(cmtp_session, session, "kcmtpd_ctr_%d",
384 								session->num);
385 	if (IS_ERR(session->task)) {
386 		module_put(THIS_MODULE);
387 		err = PTR_ERR(session->task);
388 		goto unlink;
389 	}
390 
391 	if (!(session->flags & BIT(CMTP_LOOPBACK))) {
392 		err = cmtp_attach_device(session);
393 		if (err < 0) {
394 			atomic_inc(&session->terminate);
395 			wake_up_interruptible(sk_sleep(session->sock->sk));
396 			up_write(&cmtp_session_sem);
397 			return err;
398 		}
399 	}
400 
401 	up_write(&cmtp_session_sem);
402 	return 0;
403 
404 unlink:
405 	__cmtp_unlink_session(session);
406 
407 failed:
408 	up_write(&cmtp_session_sem);
409 	kfree(session);
410 	return err;
411 }
412 
413 int cmtp_del_connection(struct cmtp_conndel_req *req)
414 {
415 	u32 valid_flags = 0;
416 	struct cmtp_session *session;
417 	int err = 0;
418 
419 	BT_DBG("");
420 
421 	if (req->flags & ~valid_flags)
422 		return -EINVAL;
423 
424 	down_read(&cmtp_session_sem);
425 
426 	session = __cmtp_get_session(&req->bdaddr);
427 	if (session) {
428 		/* Flush the transmit queue */
429 		skb_queue_purge(&session->transmit);
430 
431 		/* Stop session thread */
432 		atomic_inc(&session->terminate);
433 
434 		/* Ensure session->terminate is updated */
435 		smp_mb__after_atomic();
436 
437 		wake_up_interruptible(sk_sleep(session->sock->sk));
438 	} else
439 		err = -ENOENT;
440 
441 	up_read(&cmtp_session_sem);
442 	return err;
443 }
444 
445 int cmtp_get_connlist(struct cmtp_connlist_req *req)
446 {
447 	struct cmtp_session *session;
448 	int err = 0, n = 0;
449 
450 	BT_DBG("");
451 
452 	down_read(&cmtp_session_sem);
453 
454 	list_for_each_entry(session, &cmtp_session_list, list) {
455 		struct cmtp_conninfo ci;
456 
457 		__cmtp_copy_session(session, &ci);
458 
459 		if (copy_to_user(req->ci, &ci, sizeof(ci))) {
460 			err = -EFAULT;
461 			break;
462 		}
463 
464 		if (++n >= req->cnum)
465 			break;
466 
467 		req->ci++;
468 	}
469 	req->cnum = n;
470 
471 	up_read(&cmtp_session_sem);
472 	return err;
473 }
474 
475 int cmtp_get_conninfo(struct cmtp_conninfo *ci)
476 {
477 	struct cmtp_session *session;
478 	int err = 0;
479 
480 	down_read(&cmtp_session_sem);
481 
482 	session = __cmtp_get_session(&ci->bdaddr);
483 	if (session)
484 		__cmtp_copy_session(session, ci);
485 	else
486 		err = -ENOENT;
487 
488 	up_read(&cmtp_session_sem);
489 	return err;
490 }
491 
492 
493 static int __init cmtp_init(void)
494 {
495 	BT_INFO("CMTP (CAPI Emulation) ver %s", VERSION);
496 
497 	cmtp_init_sockets();
498 
499 	return 0;
500 }
501 
502 static void __exit cmtp_exit(void)
503 {
504 	cmtp_cleanup_sockets();
505 }
506 
507 module_init(cmtp_init);
508 module_exit(cmtp_exit);
509 
510 MODULE_AUTHOR("Marcel Holtmann <marcel@holtmann.org>");
511 MODULE_DESCRIPTION("Bluetooth CMTP ver " VERSION);
512 MODULE_VERSION(VERSION);
513 MODULE_LICENSE("GPL");
514 MODULE_ALIAS("bt-proto-5");
515