xref: /linux/net/bluetooth/cmtp/core.c (revision b889fcf63cb62e7fdb7816565e28f44dbe4a76a5) 
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 	memset(ci, 0, sizeof(*ci));
79 	bacpy(&ci->bdaddr, &session->bdaddr);
80 
81 	ci->flags = session->flags;
82 	ci->state = session->state;
83 
84 	ci->num = session->num;
85 }
86 
87 
88 static inline int cmtp_alloc_block_id(struct cmtp_session *session)
89 {
90 	int i, id = -1;
91 
92 	for (i = 0; i < 16; i++)
93 		if (!test_and_set_bit(i, &session->blockids)) {
94 			id = i;
95 			break;
96 		}
97 
98 	return id;
99 }
100 
101 static inline void cmtp_free_block_id(struct cmtp_session *session, int id)
102 {
103 	clear_bit(id, &session->blockids);
104 }
105 
106 static inline void cmtp_add_msgpart(struct cmtp_session *session, int id, const unsigned char *buf, int count)
107 {
108 	struct sk_buff *skb = session->reassembly[id], *nskb;
109 	int size;
110 
111 	BT_DBG("session %p buf %p count %d", session, buf, count);
112 
113 	size = (skb) ? skb->len + count : count;
114 
115 	nskb = alloc_skb(size, GFP_ATOMIC);
116 	if (!nskb) {
117 		BT_ERR("Can't allocate memory for CAPI message");
118 		return;
119 	}
120 
121 	if (skb && (skb->len > 0))
122 		skb_copy_from_linear_data(skb, skb_put(nskb, skb->len), skb->len);
123 
124 	memcpy(skb_put(nskb, count), buf, count);
125 
126 	session->reassembly[id] = nskb;
127 
128 	kfree_skb(skb);
129 }
130 
131 static inline int cmtp_recv_frame(struct cmtp_session *session, struct sk_buff *skb)
132 {
133 	__u8 hdr, hdrlen, id;
134 	__u16 len;
135 
136 	BT_DBG("session %p skb %p len %d", session, skb, skb->len);
137 
138 	while (skb->len > 0) {
139 		hdr = skb->data[0];
140 
141 		switch (hdr & 0xc0) {
142 		case 0x40:
143 			hdrlen = 2;
144 			len = skb->data[1];
145 			break;
146 		case 0x80:
147 			hdrlen = 3;
148 			len = skb->data[1] | (skb->data[2] << 8);
149 			break;
150 		default:
151 			hdrlen = 1;
152 			len = 0;
153 			break;
154 		}
155 
156 		id = (hdr & 0x3c) >> 2;
157 
158 		BT_DBG("hdr 0x%02x hdrlen %d len %d id %d", hdr, hdrlen, len, id);
159 
160 		if (hdrlen + len > skb->len) {
161 			BT_ERR("Wrong size or header information in CMTP frame");
162 			break;
163 		}
164 
165 		if (len == 0) {
166 			skb_pull(skb, hdrlen);
167 			continue;
168 		}
169 
170 		switch (hdr & 0x03) {
171 		case 0x00:
172 			cmtp_add_msgpart(session, id, skb->data + hdrlen, len);
173 			cmtp_recv_capimsg(session, session->reassembly[id]);
174 			session->reassembly[id] = NULL;
175 			break;
176 		case 0x01:
177 			cmtp_add_msgpart(session, id, skb->data + hdrlen, len);
178 			break;
179 		default:
180 			if (session->reassembly[id] != NULL)
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 	wait_queue_t wait;
284 
285 	BT_DBG("session %p", session);
286 
287 	set_user_nice(current, -15);
288 
289 	init_waitqueue_entry(&wait, current);
290 	add_wait_queue(sk_sleep(sk), &wait);
291 	while (1) {
292 		set_current_state(TASK_INTERRUPTIBLE);
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 		schedule();
310 	}
311 	__set_current_state(TASK_RUNNING);
312 	remove_wait_queue(sk_sleep(sk), &wait);
313 
314 	down_write(&cmtp_session_sem);
315 
316 	if (!(session->flags & (1 << CMTP_LOOPBACK)))
317 		cmtp_detach_device(session);
318 
319 	fput(session->sock->file);
320 
321 	__cmtp_unlink_session(session);
322 
323 	up_write(&cmtp_session_sem);
324 
325 	kfree(session);
326 	module_put_and_exit(0);
327 	return 0;
328 }
329 
330 int cmtp_add_connection(struct cmtp_connadd_req *req, struct socket *sock)
331 {
332 	struct cmtp_session *session, *s;
333 	int i, err;
334 
335 	BT_DBG("");
336 
337 	session = kzalloc(sizeof(struct cmtp_session), GFP_KERNEL);
338 	if (!session)
339 		return -ENOMEM;
340 
341 	down_write(&cmtp_session_sem);
342 
343 	s = __cmtp_get_session(&bt_sk(sock->sk)->dst);
344 	if (s && s->state == BT_CONNECTED) {
345 		err = -EEXIST;
346 		goto failed;
347 	}
348 
349 	bacpy(&session->bdaddr, &bt_sk(sock->sk)->dst);
350 
351 	session->mtu = min_t(uint, l2cap_pi(sock->sk)->chan->omtu,
352 					l2cap_pi(sock->sk)->chan->imtu);
353 
354 	BT_DBG("mtu %d", session->mtu);
355 
356 	sprintf(session->name, "%pMR", &bt_sk(sock->sk)->dst);
357 
358 	session->sock  = sock;
359 	session->state = BT_CONFIG;
360 
361 	init_waitqueue_head(&session->wait);
362 
363 	session->msgnum = CMTP_INITIAL_MSGNUM;
364 
365 	INIT_LIST_HEAD(&session->applications);
366 
367 	skb_queue_head_init(&session->transmit);
368 
369 	for (i = 0; i < 16; i++)
370 		session->reassembly[i] = NULL;
371 
372 	session->flags = req->flags;
373 
374 	__cmtp_link_session(session);
375 
376 	__module_get(THIS_MODULE);
377 	session->task = kthread_run(cmtp_session, session, "kcmtpd_ctr_%d",
378 								session->num);
379 	if (IS_ERR(session->task)) {
380 		module_put(THIS_MODULE);
381 		err = PTR_ERR(session->task);
382 		goto unlink;
383 	}
384 
385 	if (!(session->flags & (1 << CMTP_LOOPBACK))) {
386 		err = cmtp_attach_device(session);
387 		if (err < 0) {
388 			atomic_inc(&session->terminate);
389 			wake_up_process(session->task);
390 			up_write(&cmtp_session_sem);
391 			return err;
392 		}
393 	}
394 
395 	up_write(&cmtp_session_sem);
396 	return 0;
397 
398 unlink:
399 	__cmtp_unlink_session(session);
400 
401 failed:
402 	up_write(&cmtp_session_sem);
403 	kfree(session);
404 	return err;
405 }
406 
407 int cmtp_del_connection(struct cmtp_conndel_req *req)
408 {
409 	struct cmtp_session *session;
410 	int err = 0;
411 
412 	BT_DBG("");
413 
414 	down_read(&cmtp_session_sem);
415 
416 	session = __cmtp_get_session(&req->bdaddr);
417 	if (session) {
418 		/* Flush the transmit queue */
419 		skb_queue_purge(&session->transmit);
420 
421 		/* Stop session thread */
422 		atomic_inc(&session->terminate);
423 		wake_up_process(session->task);
424 	} else
425 		err = -ENOENT;
426 
427 	up_read(&cmtp_session_sem);
428 	return err;
429 }
430 
431 int cmtp_get_connlist(struct cmtp_connlist_req *req)
432 {
433 	struct cmtp_session *session;
434 	int err = 0, n = 0;
435 
436 	BT_DBG("");
437 
438 	down_read(&cmtp_session_sem);
439 
440 	list_for_each_entry(session, &cmtp_session_list, list) {
441 		struct cmtp_conninfo ci;
442 
443 		__cmtp_copy_session(session, &ci);
444 
445 		if (copy_to_user(req->ci, &ci, sizeof(ci))) {
446 			err = -EFAULT;
447 			break;
448 		}
449 
450 		if (++n >= req->cnum)
451 			break;
452 
453 		req->ci++;
454 	}
455 	req->cnum = n;
456 
457 	up_read(&cmtp_session_sem);
458 	return err;
459 }
460 
461 int cmtp_get_conninfo(struct cmtp_conninfo *ci)
462 {
463 	struct cmtp_session *session;
464 	int err = 0;
465 
466 	down_read(&cmtp_session_sem);
467 
468 	session = __cmtp_get_session(&ci->bdaddr);
469 	if (session)
470 		__cmtp_copy_session(session, ci);
471 	else
472 		err = -ENOENT;
473 
474 	up_read(&cmtp_session_sem);
475 	return err;
476 }
477 
478 
479 static int __init cmtp_init(void)
480 {
481 	BT_INFO("CMTP (CAPI Emulation) ver %s", VERSION);
482 
483 	cmtp_init_sockets();
484 
485 	return 0;
486 }
487 
488 static void __exit cmtp_exit(void)
489 {
490 	cmtp_cleanup_sockets();
491 }
492 
493 module_init(cmtp_init);
494 module_exit(cmtp_exit);
495 
496 MODULE_AUTHOR("Marcel Holtmann <marcel@holtmann.org>");
497 MODULE_DESCRIPTION("Bluetooth CMTP ver " VERSION);
498 MODULE_VERSION(VERSION);
499 MODULE_LICENSE("GPL");
500 MODULE_ALIAS("bt-proto-5");
501