xref: /linux/net/bluetooth/rfcomm/core.c (revision 811f35ff59b6f99ae272d6f5b96bc9e974f88196)
1 /*
2    RFCOMM implementation for Linux Bluetooth stack (BlueZ).
3    Copyright (C) 2002 Maxim Krasnyansky <maxk@qualcomm.com>
4    Copyright (C) 2002 Marcel Holtmann <marcel@holtmann.org>
5 
6    This program is free software; you can redistribute it and/or modify
7    it under the terms of the GNU General Public License version 2 as
8    published by the Free Software Foundation;
9 
10    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
11    OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
12    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS.
13    IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) AND AUTHOR(S) BE LIABLE FOR ANY
14    CLAIM, OR ANY SPECIAL INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES
15    WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
16    ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
17    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18 
19    ALL LIABILITY, INCLUDING LIABILITY FOR INFRINGEMENT OF ANY PATENTS,
20    COPYRIGHTS, TRADEMARKS OR OTHER RIGHTS, RELATING TO USE OF THIS
21    SOFTWARE IS DISCLAIMED.
22 */
23 
24 /*
25  * Bluetooth RFCOMM core.
26  */
27 
28 #include <linux/module.h>
29 #include <linux/debugfs.h>
30 #include <linux/kthread.h>
31 #include <asm/unaligned.h>
32 
33 #include <net/bluetooth/bluetooth.h>
34 #include <net/bluetooth/hci_core.h>
35 #include <net/bluetooth/l2cap.h>
36 #include <net/bluetooth/rfcomm.h>
37 
38 #define VERSION "1.11"
39 
40 static bool disable_cfc;
41 static bool l2cap_ertm;
42 static int channel_mtu = -1;
43 
44 static struct task_struct *rfcomm_thread;
45 
46 static DEFINE_MUTEX(rfcomm_mutex);
47 #define rfcomm_lock()	mutex_lock(&rfcomm_mutex)
48 #define rfcomm_unlock()	mutex_unlock(&rfcomm_mutex)
49 
50 
51 static LIST_HEAD(session_list);
52 
53 static int rfcomm_send_frame(struct rfcomm_session *s, u8 *data, int len);
54 static int rfcomm_send_sabm(struct rfcomm_session *s, u8 dlci);
55 static int rfcomm_send_disc(struct rfcomm_session *s, u8 dlci);
56 static int rfcomm_queue_disc(struct rfcomm_dlc *d);
57 static int rfcomm_send_nsc(struct rfcomm_session *s, int cr, u8 type);
58 static int rfcomm_send_pn(struct rfcomm_session *s, int cr, struct rfcomm_dlc *d);
59 static int rfcomm_send_msc(struct rfcomm_session *s, int cr, u8 dlci, u8 v24_sig);
60 static int rfcomm_send_test(struct rfcomm_session *s, int cr, u8 *pattern, int len);
61 static int rfcomm_send_credits(struct rfcomm_session *s, u8 addr, u8 credits);
62 static void rfcomm_make_uih(struct sk_buff *skb, u8 addr);
63 
64 static void rfcomm_process_connect(struct rfcomm_session *s);
65 
66 static struct rfcomm_session *rfcomm_session_create(bdaddr_t *src,
67 							bdaddr_t *dst,
68 							u8 sec_level,
69 							int *err);
70 static struct rfcomm_session *rfcomm_session_get(bdaddr_t *src, bdaddr_t *dst);
71 static struct rfcomm_session *rfcomm_session_del(struct rfcomm_session *s);
72 
73 /* ---- RFCOMM frame parsing macros ---- */
74 #define __get_dlci(b)     ((b & 0xfc) >> 2)
75 #define __get_type(b)     ((b & 0xef))
76 
77 #define __test_ea(b)      ((b & 0x01))
78 #define __test_cr(b)      (!!(b & 0x02))
79 #define __test_pf(b)      (!!(b & 0x10))
80 
81 #define __session_dir(s)  ((s)->initiator ? 0x00 : 0x01)
82 
83 #define __addr(cr, dlci)       (((dlci & 0x3f) << 2) | (cr << 1) | 0x01)
84 #define __ctrl(type, pf)       (((type & 0xef) | (pf << 4)))
85 #define __dlci(dir, chn)       (((chn & 0x1f) << 1) | dir)
86 #define __srv_channel(dlci)    (dlci >> 1)
87 
88 #define __len8(len)       (((len) << 1) | 1)
89 #define __len16(len)      ((len) << 1)
90 
91 /* MCC macros */
92 #define __mcc_type(cr, type)   (((type << 2) | (cr << 1) | 0x01))
93 #define __get_mcc_type(b) ((b & 0xfc) >> 2)
94 #define __get_mcc_len(b)  ((b & 0xfe) >> 1)
95 
96 /* RPN macros */
97 #define __rpn_line_settings(data, stop, parity)  ((data & 0x3) | ((stop & 0x1) << 2) | ((parity & 0x7) << 3))
98 #define __get_rpn_data_bits(line) ((line) & 0x3)
99 #define __get_rpn_stop_bits(line) (((line) >> 2) & 0x1)
100 #define __get_rpn_parity(line)    (((line) >> 3) & 0x7)
101 
102 static DECLARE_WAIT_QUEUE_HEAD(rfcomm_wq);
103 
104 static void rfcomm_schedule(void)
105 {
106 	wake_up_all(&rfcomm_wq);
107 }
108 
109 /* ---- RFCOMM FCS computation ---- */
110 
111 /* reversed, 8-bit, poly=0x07 */
112 static unsigned char rfcomm_crc_table[256] = {
113 	0x00, 0x91, 0xe3, 0x72, 0x07, 0x96, 0xe4, 0x75,
114 	0x0e, 0x9f, 0xed, 0x7c, 0x09, 0x98, 0xea, 0x7b,
115 	0x1c, 0x8d, 0xff, 0x6e, 0x1b, 0x8a, 0xf8, 0x69,
116 	0x12, 0x83, 0xf1, 0x60, 0x15, 0x84, 0xf6, 0x67,
117 
118 	0x38, 0xa9, 0xdb, 0x4a, 0x3f, 0xae, 0xdc, 0x4d,
119 	0x36, 0xa7, 0xd5, 0x44, 0x31, 0xa0, 0xd2, 0x43,
120 	0x24, 0xb5, 0xc7, 0x56, 0x23, 0xb2, 0xc0, 0x51,
121 	0x2a, 0xbb, 0xc9, 0x58, 0x2d, 0xbc, 0xce, 0x5f,
122 
123 	0x70, 0xe1, 0x93, 0x02, 0x77, 0xe6, 0x94, 0x05,
124 	0x7e, 0xef, 0x9d, 0x0c, 0x79, 0xe8, 0x9a, 0x0b,
125 	0x6c, 0xfd, 0x8f, 0x1e, 0x6b, 0xfa, 0x88, 0x19,
126 	0x62, 0xf3, 0x81, 0x10, 0x65, 0xf4, 0x86, 0x17,
127 
128 	0x48, 0xd9, 0xab, 0x3a, 0x4f, 0xde, 0xac, 0x3d,
129 	0x46, 0xd7, 0xa5, 0x34, 0x41, 0xd0, 0xa2, 0x33,
130 	0x54, 0xc5, 0xb7, 0x26, 0x53, 0xc2, 0xb0, 0x21,
131 	0x5a, 0xcb, 0xb9, 0x28, 0x5d, 0xcc, 0xbe, 0x2f,
132 
133 	0xe0, 0x71, 0x03, 0x92, 0xe7, 0x76, 0x04, 0x95,
134 	0xee, 0x7f, 0x0d, 0x9c, 0xe9, 0x78, 0x0a, 0x9b,
135 	0xfc, 0x6d, 0x1f, 0x8e, 0xfb, 0x6a, 0x18, 0x89,
136 	0xf2, 0x63, 0x11, 0x80, 0xf5, 0x64, 0x16, 0x87,
137 
138 	0xd8, 0x49, 0x3b, 0xaa, 0xdf, 0x4e, 0x3c, 0xad,
139 	0xd6, 0x47, 0x35, 0xa4, 0xd1, 0x40, 0x32, 0xa3,
140 	0xc4, 0x55, 0x27, 0xb6, 0xc3, 0x52, 0x20, 0xb1,
141 	0xca, 0x5b, 0x29, 0xb8, 0xcd, 0x5c, 0x2e, 0xbf,
142 
143 	0x90, 0x01, 0x73, 0xe2, 0x97, 0x06, 0x74, 0xe5,
144 	0x9e, 0x0f, 0x7d, 0xec, 0x99, 0x08, 0x7a, 0xeb,
145 	0x8c, 0x1d, 0x6f, 0xfe, 0x8b, 0x1a, 0x68, 0xf9,
146 	0x82, 0x13, 0x61, 0xf0, 0x85, 0x14, 0x66, 0xf7,
147 
148 	0xa8, 0x39, 0x4b, 0xda, 0xaf, 0x3e, 0x4c, 0xdd,
149 	0xa6, 0x37, 0x45, 0xd4, 0xa1, 0x30, 0x42, 0xd3,
150 	0xb4, 0x25, 0x57, 0xc6, 0xb3, 0x22, 0x50, 0xc1,
151 	0xba, 0x2b, 0x59, 0xc8, 0xbd, 0x2c, 0x5e, 0xcf
152 };
153 
154 /* CRC on 2 bytes */
155 #define __crc(data) (rfcomm_crc_table[rfcomm_crc_table[0xff ^ data[0]] ^ data[1]])
156 
157 /* FCS on 2 bytes */
158 static inline u8 __fcs(u8 *data)
159 {
160 	return 0xff - __crc(data);
161 }
162 
163 /* FCS on 3 bytes */
164 static inline u8 __fcs2(u8 *data)
165 {
166 	return 0xff - rfcomm_crc_table[__crc(data) ^ data[2]];
167 }
168 
169 /* Check FCS */
170 static inline int __check_fcs(u8 *data, int type, u8 fcs)
171 {
172 	u8 f = __crc(data);
173 
174 	if (type != RFCOMM_UIH)
175 		f = rfcomm_crc_table[f ^ data[2]];
176 
177 	return rfcomm_crc_table[f ^ fcs] != 0xcf;
178 }
179 
180 /* ---- L2CAP callbacks ---- */
181 static void rfcomm_l2state_change(struct sock *sk)
182 {
183 	BT_DBG("%p state %d", sk, sk->sk_state);
184 	rfcomm_schedule();
185 }
186 
187 static void rfcomm_l2data_ready(struct sock *sk)
188 {
189 	BT_DBG("%p", sk);
190 	rfcomm_schedule();
191 }
192 
193 static int rfcomm_l2sock_create(struct socket **sock)
194 {
195 	int err;
196 
197 	BT_DBG("");
198 
199 	err = sock_create_kern(&init_net, PF_BLUETOOTH, SOCK_SEQPACKET, BTPROTO_L2CAP, sock);
200 	if (!err) {
201 		struct sock *sk = (*sock)->sk;
202 		sk->sk_data_ready   = rfcomm_l2data_ready;
203 		sk->sk_state_change = rfcomm_l2state_change;
204 	}
205 	return err;
206 }
207 
208 static int rfcomm_check_security(struct rfcomm_dlc *d)
209 {
210 	struct sock *sk = d->session->sock->sk;
211 	struct l2cap_conn *conn = l2cap_pi(sk)->chan->conn;
212 
213 	__u8 auth_type;
214 
215 	switch (d->sec_level) {
216 	case BT_SECURITY_HIGH:
217 	case BT_SECURITY_FIPS:
218 		auth_type = HCI_AT_GENERAL_BONDING_MITM;
219 		break;
220 	case BT_SECURITY_MEDIUM:
221 		auth_type = HCI_AT_GENERAL_BONDING;
222 		break;
223 	default:
224 		auth_type = HCI_AT_NO_BONDING;
225 		break;
226 	}
227 
228 	return hci_conn_security(conn->hcon, d->sec_level, auth_type,
229 				 d->out);
230 }
231 
232 static void rfcomm_session_timeout(struct timer_list *t)
233 {
234 	struct rfcomm_session *s = from_timer(s, t, timer);
235 
236 	BT_DBG("session %p state %ld", s, s->state);
237 
238 	set_bit(RFCOMM_TIMED_OUT, &s->flags);
239 	rfcomm_schedule();
240 }
241 
242 static void rfcomm_session_set_timer(struct rfcomm_session *s, long timeout)
243 {
244 	BT_DBG("session %p state %ld timeout %ld", s, s->state, timeout);
245 
246 	mod_timer(&s->timer, jiffies + timeout);
247 }
248 
249 static void rfcomm_session_clear_timer(struct rfcomm_session *s)
250 {
251 	BT_DBG("session %p state %ld", s, s->state);
252 
253 	del_timer_sync(&s->timer);
254 }
255 
256 /* ---- RFCOMM DLCs ---- */
257 static void rfcomm_dlc_timeout(struct timer_list *t)
258 {
259 	struct rfcomm_dlc *d = from_timer(d, t, timer);
260 
261 	BT_DBG("dlc %p state %ld", d, d->state);
262 
263 	set_bit(RFCOMM_TIMED_OUT, &d->flags);
264 	rfcomm_dlc_put(d);
265 	rfcomm_schedule();
266 }
267 
268 static void rfcomm_dlc_set_timer(struct rfcomm_dlc *d, long timeout)
269 {
270 	BT_DBG("dlc %p state %ld timeout %ld", d, d->state, timeout);
271 
272 	if (!mod_timer(&d->timer, jiffies + timeout))
273 		rfcomm_dlc_hold(d);
274 }
275 
276 static void rfcomm_dlc_clear_timer(struct rfcomm_dlc *d)
277 {
278 	BT_DBG("dlc %p state %ld", d, d->state);
279 
280 	if (del_timer(&d->timer))
281 		rfcomm_dlc_put(d);
282 }
283 
284 static void rfcomm_dlc_clear_state(struct rfcomm_dlc *d)
285 {
286 	BT_DBG("%p", d);
287 
288 	d->state      = BT_OPEN;
289 	d->flags      = 0;
290 	d->mscex      = 0;
291 	d->sec_level  = BT_SECURITY_LOW;
292 	d->mtu        = RFCOMM_DEFAULT_MTU;
293 	d->v24_sig    = RFCOMM_V24_RTC | RFCOMM_V24_RTR | RFCOMM_V24_DV;
294 
295 	d->cfc        = RFCOMM_CFC_DISABLED;
296 	d->rx_credits = RFCOMM_DEFAULT_CREDITS;
297 }
298 
299 struct rfcomm_dlc *rfcomm_dlc_alloc(gfp_t prio)
300 {
301 	struct rfcomm_dlc *d = kzalloc(sizeof(*d), prio);
302 
303 	if (!d)
304 		return NULL;
305 
306 	timer_setup(&d->timer, rfcomm_dlc_timeout, 0);
307 
308 	skb_queue_head_init(&d->tx_queue);
309 	mutex_init(&d->lock);
310 	refcount_set(&d->refcnt, 1);
311 
312 	rfcomm_dlc_clear_state(d);
313 
314 	BT_DBG("%p", d);
315 
316 	return d;
317 }
318 
319 void rfcomm_dlc_free(struct rfcomm_dlc *d)
320 {
321 	BT_DBG("%p", d);
322 
323 	skb_queue_purge(&d->tx_queue);
324 	kfree(d);
325 }
326 
327 static void rfcomm_dlc_link(struct rfcomm_session *s, struct rfcomm_dlc *d)
328 {
329 	BT_DBG("dlc %p session %p", d, s);
330 
331 	rfcomm_session_clear_timer(s);
332 	rfcomm_dlc_hold(d);
333 	list_add(&d->list, &s->dlcs);
334 	d->session = s;
335 }
336 
337 static void rfcomm_dlc_unlink(struct rfcomm_dlc *d)
338 {
339 	struct rfcomm_session *s = d->session;
340 
341 	BT_DBG("dlc %p refcnt %d session %p", d, refcount_read(&d->refcnt), s);
342 
343 	list_del(&d->list);
344 	d->session = NULL;
345 	rfcomm_dlc_put(d);
346 
347 	if (list_empty(&s->dlcs))
348 		rfcomm_session_set_timer(s, RFCOMM_IDLE_TIMEOUT);
349 }
350 
351 static struct rfcomm_dlc *rfcomm_dlc_get(struct rfcomm_session *s, u8 dlci)
352 {
353 	struct rfcomm_dlc *d;
354 
355 	list_for_each_entry(d, &s->dlcs, list)
356 		if (d->dlci == dlci)
357 			return d;
358 
359 	return NULL;
360 }
361 
362 static int rfcomm_check_channel(u8 channel)
363 {
364 	return channel < 1 || channel > 30;
365 }
366 
367 static int __rfcomm_dlc_open(struct rfcomm_dlc *d, bdaddr_t *src, bdaddr_t *dst, u8 channel)
368 {
369 	struct rfcomm_session *s;
370 	int err = 0;
371 	u8 dlci;
372 
373 	BT_DBG("dlc %p state %ld %pMR -> %pMR channel %d",
374 	       d, d->state, src, dst, channel);
375 
376 	if (rfcomm_check_channel(channel))
377 		return -EINVAL;
378 
379 	if (d->state != BT_OPEN && d->state != BT_CLOSED)
380 		return 0;
381 
382 	s = rfcomm_session_get(src, dst);
383 	if (!s) {
384 		s = rfcomm_session_create(src, dst, d->sec_level, &err);
385 		if (!s)
386 			return err;
387 	}
388 
389 	dlci = __dlci(__session_dir(s), channel);
390 
391 	/* Check if DLCI already exists */
392 	if (rfcomm_dlc_get(s, dlci))
393 		return -EBUSY;
394 
395 	rfcomm_dlc_clear_state(d);
396 
397 	d->dlci     = dlci;
398 	d->addr     = __addr(s->initiator, dlci);
399 	d->priority = 7;
400 
401 	d->state = BT_CONFIG;
402 	rfcomm_dlc_link(s, d);
403 
404 	d->out = 1;
405 
406 	d->mtu = s->mtu;
407 	d->cfc = (s->cfc == RFCOMM_CFC_UNKNOWN) ? 0 : s->cfc;
408 
409 	if (s->state == BT_CONNECTED) {
410 		if (rfcomm_check_security(d))
411 			rfcomm_send_pn(s, 1, d);
412 		else
413 			set_bit(RFCOMM_AUTH_PENDING, &d->flags);
414 	}
415 
416 	rfcomm_dlc_set_timer(d, RFCOMM_CONN_TIMEOUT);
417 
418 	return 0;
419 }
420 
421 int rfcomm_dlc_open(struct rfcomm_dlc *d, bdaddr_t *src, bdaddr_t *dst, u8 channel)
422 {
423 	int r;
424 
425 	rfcomm_lock();
426 
427 	r = __rfcomm_dlc_open(d, src, dst, channel);
428 
429 	rfcomm_unlock();
430 	return r;
431 }
432 
433 static void __rfcomm_dlc_disconn(struct rfcomm_dlc *d)
434 {
435 	struct rfcomm_session *s = d->session;
436 
437 	d->state = BT_DISCONN;
438 	if (skb_queue_empty(&d->tx_queue)) {
439 		rfcomm_send_disc(s, d->dlci);
440 		rfcomm_dlc_set_timer(d, RFCOMM_DISC_TIMEOUT);
441 	} else {
442 		rfcomm_queue_disc(d);
443 		rfcomm_dlc_set_timer(d, RFCOMM_DISC_TIMEOUT * 2);
444 	}
445 }
446 
447 static int __rfcomm_dlc_close(struct rfcomm_dlc *d, int err)
448 {
449 	struct rfcomm_session *s = d->session;
450 	if (!s)
451 		return 0;
452 
453 	BT_DBG("dlc %p state %ld dlci %d err %d session %p",
454 			d, d->state, d->dlci, err, s);
455 
456 	switch (d->state) {
457 	case BT_CONNECT:
458 	case BT_CONFIG:
459 	case BT_OPEN:
460 	case BT_CONNECT2:
461 		if (test_and_clear_bit(RFCOMM_DEFER_SETUP, &d->flags)) {
462 			set_bit(RFCOMM_AUTH_REJECT, &d->flags);
463 			rfcomm_schedule();
464 			return 0;
465 		}
466 	}
467 
468 	switch (d->state) {
469 	case BT_CONNECT:
470 	case BT_CONNECTED:
471 		__rfcomm_dlc_disconn(d);
472 		break;
473 
474 	case BT_CONFIG:
475 		if (s->state != BT_BOUND) {
476 			__rfcomm_dlc_disconn(d);
477 			break;
478 		}
479 		/* if closing a dlc in a session that hasn't been started,
480 		 * just close and unlink the dlc
481 		 */
482 		fallthrough;
483 
484 	default:
485 		rfcomm_dlc_clear_timer(d);
486 
487 		rfcomm_dlc_lock(d);
488 		d->state = BT_CLOSED;
489 		d->state_change(d, err);
490 		rfcomm_dlc_unlock(d);
491 
492 		skb_queue_purge(&d->tx_queue);
493 		rfcomm_dlc_unlink(d);
494 	}
495 
496 	return 0;
497 }
498 
499 int rfcomm_dlc_close(struct rfcomm_dlc *d, int err)
500 {
501 	int r = 0;
502 	struct rfcomm_dlc *d_list;
503 	struct rfcomm_session *s, *s_list;
504 
505 	BT_DBG("dlc %p state %ld dlci %d err %d", d, d->state, d->dlci, err);
506 
507 	rfcomm_lock();
508 
509 	s = d->session;
510 	if (!s)
511 		goto no_session;
512 
513 	/* after waiting on the mutex check the session still exists
514 	 * then check the dlc still exists
515 	 */
516 	list_for_each_entry(s_list, &session_list, list) {
517 		if (s_list == s) {
518 			list_for_each_entry(d_list, &s->dlcs, list) {
519 				if (d_list == d) {
520 					r = __rfcomm_dlc_close(d, err);
521 					break;
522 				}
523 			}
524 			break;
525 		}
526 	}
527 
528 no_session:
529 	rfcomm_unlock();
530 	return r;
531 }
532 
533 struct rfcomm_dlc *rfcomm_dlc_exists(bdaddr_t *src, bdaddr_t *dst, u8 channel)
534 {
535 	struct rfcomm_session *s;
536 	struct rfcomm_dlc *dlc = NULL;
537 	u8 dlci;
538 
539 	if (rfcomm_check_channel(channel))
540 		return ERR_PTR(-EINVAL);
541 
542 	rfcomm_lock();
543 	s = rfcomm_session_get(src, dst);
544 	if (s) {
545 		dlci = __dlci(__session_dir(s), channel);
546 		dlc = rfcomm_dlc_get(s, dlci);
547 	}
548 	rfcomm_unlock();
549 	return dlc;
550 }
551 
552 static int rfcomm_dlc_send_frag(struct rfcomm_dlc *d, struct sk_buff *frag)
553 {
554 	int len = frag->len;
555 
556 	BT_DBG("dlc %p mtu %d len %d", d, d->mtu, len);
557 
558 	if (len > d->mtu)
559 		return -EINVAL;
560 
561 	rfcomm_make_uih(frag, d->addr);
562 	__skb_queue_tail(&d->tx_queue, frag);
563 
564 	return len;
565 }
566 
567 int rfcomm_dlc_send(struct rfcomm_dlc *d, struct sk_buff *skb)
568 {
569 	unsigned long flags;
570 	struct sk_buff *frag, *next;
571 	int len;
572 
573 	if (d->state != BT_CONNECTED)
574 		return -ENOTCONN;
575 
576 	frag = skb_shinfo(skb)->frag_list;
577 	skb_shinfo(skb)->frag_list = NULL;
578 
579 	/* Queue all fragments atomically. */
580 	spin_lock_irqsave(&d->tx_queue.lock, flags);
581 
582 	len = rfcomm_dlc_send_frag(d, skb);
583 	if (len < 0 || !frag)
584 		goto unlock;
585 
586 	for (; frag; frag = next) {
587 		int ret;
588 
589 		next = frag->next;
590 
591 		ret = rfcomm_dlc_send_frag(d, frag);
592 		if (ret < 0) {
593 			dev_kfree_skb_irq(frag);
594 			goto unlock;
595 		}
596 
597 		len += ret;
598 	}
599 
600 unlock:
601 	spin_unlock_irqrestore(&d->tx_queue.lock, flags);
602 
603 	if (len > 0 && !test_bit(RFCOMM_TX_THROTTLED, &d->flags))
604 		rfcomm_schedule();
605 	return len;
606 }
607 
608 void rfcomm_dlc_send_noerror(struct rfcomm_dlc *d, struct sk_buff *skb)
609 {
610 	int len = skb->len;
611 
612 	BT_DBG("dlc %p mtu %d len %d", d, d->mtu, len);
613 
614 	rfcomm_make_uih(skb, d->addr);
615 	skb_queue_tail(&d->tx_queue, skb);
616 
617 	if (d->state == BT_CONNECTED &&
618 	    !test_bit(RFCOMM_TX_THROTTLED, &d->flags))
619 		rfcomm_schedule();
620 }
621 
622 void __rfcomm_dlc_throttle(struct rfcomm_dlc *d)
623 {
624 	BT_DBG("dlc %p state %ld", d, d->state);
625 
626 	if (!d->cfc) {
627 		d->v24_sig |= RFCOMM_V24_FC;
628 		set_bit(RFCOMM_MSC_PENDING, &d->flags);
629 	}
630 	rfcomm_schedule();
631 }
632 
633 void __rfcomm_dlc_unthrottle(struct rfcomm_dlc *d)
634 {
635 	BT_DBG("dlc %p state %ld", d, d->state);
636 
637 	if (!d->cfc) {
638 		d->v24_sig &= ~RFCOMM_V24_FC;
639 		set_bit(RFCOMM_MSC_PENDING, &d->flags);
640 	}
641 	rfcomm_schedule();
642 }
643 
644 /*
645    Set/get modem status functions use _local_ status i.e. what we report
646    to the other side.
647    Remote status is provided by dlc->modem_status() callback.
648  */
649 int rfcomm_dlc_set_modem_status(struct rfcomm_dlc *d, u8 v24_sig)
650 {
651 	BT_DBG("dlc %p state %ld v24_sig 0x%x",
652 			d, d->state, v24_sig);
653 
654 	if (test_bit(RFCOMM_RX_THROTTLED, &d->flags))
655 		v24_sig |= RFCOMM_V24_FC;
656 	else
657 		v24_sig &= ~RFCOMM_V24_FC;
658 
659 	d->v24_sig = v24_sig;
660 
661 	if (!test_and_set_bit(RFCOMM_MSC_PENDING, &d->flags))
662 		rfcomm_schedule();
663 
664 	return 0;
665 }
666 
667 int rfcomm_dlc_get_modem_status(struct rfcomm_dlc *d, u8 *v24_sig)
668 {
669 	BT_DBG("dlc %p state %ld v24_sig 0x%x",
670 			d, d->state, d->v24_sig);
671 
672 	*v24_sig = d->v24_sig;
673 	return 0;
674 }
675 
676 /* ---- RFCOMM sessions ---- */
677 static struct rfcomm_session *rfcomm_session_add(struct socket *sock, int state)
678 {
679 	struct rfcomm_session *s = kzalloc(sizeof(*s), GFP_KERNEL);
680 
681 	if (!s)
682 		return NULL;
683 
684 	BT_DBG("session %p sock %p", s, sock);
685 
686 	timer_setup(&s->timer, rfcomm_session_timeout, 0);
687 
688 	INIT_LIST_HEAD(&s->dlcs);
689 	s->state = state;
690 	s->sock  = sock;
691 
692 	s->mtu = RFCOMM_DEFAULT_MTU;
693 	s->cfc = disable_cfc ? RFCOMM_CFC_DISABLED : RFCOMM_CFC_UNKNOWN;
694 
695 	/* Do not increment module usage count for listening sessions.
696 	 * Otherwise we won't be able to unload the module. */
697 	if (state != BT_LISTEN)
698 		if (!try_module_get(THIS_MODULE)) {
699 			kfree(s);
700 			return NULL;
701 		}
702 
703 	list_add(&s->list, &session_list);
704 
705 	return s;
706 }
707 
708 static struct rfcomm_session *rfcomm_session_del(struct rfcomm_session *s)
709 {
710 	int state = s->state;
711 
712 	BT_DBG("session %p state %ld", s, s->state);
713 
714 	list_del(&s->list);
715 
716 	rfcomm_session_clear_timer(s);
717 	sock_release(s->sock);
718 	kfree(s);
719 
720 	if (state != BT_LISTEN)
721 		module_put(THIS_MODULE);
722 
723 	return NULL;
724 }
725 
726 static struct rfcomm_session *rfcomm_session_get(bdaddr_t *src, bdaddr_t *dst)
727 {
728 	struct rfcomm_session *s, *n;
729 	struct l2cap_chan *chan;
730 	list_for_each_entry_safe(s, n, &session_list, list) {
731 		chan = l2cap_pi(s->sock->sk)->chan;
732 
733 		if ((!bacmp(src, BDADDR_ANY) || !bacmp(&chan->src, src)) &&
734 		    !bacmp(&chan->dst, dst))
735 			return s;
736 	}
737 	return NULL;
738 }
739 
740 static struct rfcomm_session *rfcomm_session_close(struct rfcomm_session *s,
741 						   int err)
742 {
743 	struct rfcomm_dlc *d, *n;
744 
745 	s->state = BT_CLOSED;
746 
747 	BT_DBG("session %p state %ld err %d", s, s->state, err);
748 
749 	/* Close all dlcs */
750 	list_for_each_entry_safe(d, n, &s->dlcs, list) {
751 		d->state = BT_CLOSED;
752 		__rfcomm_dlc_close(d, err);
753 	}
754 
755 	rfcomm_session_clear_timer(s);
756 	return rfcomm_session_del(s);
757 }
758 
759 static struct rfcomm_session *rfcomm_session_create(bdaddr_t *src,
760 							bdaddr_t *dst,
761 							u8 sec_level,
762 							int *err)
763 {
764 	struct rfcomm_session *s = NULL;
765 	struct sockaddr_l2 addr;
766 	struct socket *sock;
767 	struct sock *sk;
768 
769 	BT_DBG("%pMR -> %pMR", src, dst);
770 
771 	*err = rfcomm_l2sock_create(&sock);
772 	if (*err < 0)
773 		return NULL;
774 
775 	bacpy(&addr.l2_bdaddr, src);
776 	addr.l2_family = AF_BLUETOOTH;
777 	addr.l2_psm    = 0;
778 	addr.l2_cid    = 0;
779 	addr.l2_bdaddr_type = BDADDR_BREDR;
780 	*err = kernel_bind(sock, (struct sockaddr *) &addr, sizeof(addr));
781 	if (*err < 0)
782 		goto failed;
783 
784 	/* Set L2CAP options */
785 	sk = sock->sk;
786 	lock_sock(sk);
787 	/* Set MTU to 0 so L2CAP can auto select the MTU */
788 	l2cap_pi(sk)->chan->imtu = 0;
789 	l2cap_pi(sk)->chan->sec_level = sec_level;
790 	if (l2cap_ertm)
791 		l2cap_pi(sk)->chan->mode = L2CAP_MODE_ERTM;
792 	release_sock(sk);
793 
794 	s = rfcomm_session_add(sock, BT_BOUND);
795 	if (!s) {
796 		*err = -ENOMEM;
797 		goto failed;
798 	}
799 
800 	s->initiator = 1;
801 
802 	bacpy(&addr.l2_bdaddr, dst);
803 	addr.l2_family = AF_BLUETOOTH;
804 	addr.l2_psm    = cpu_to_le16(L2CAP_PSM_RFCOMM);
805 	addr.l2_cid    = 0;
806 	addr.l2_bdaddr_type = BDADDR_BREDR;
807 	*err = kernel_connect(sock, (struct sockaddr *) &addr, sizeof(addr), O_NONBLOCK);
808 	if (*err == 0 || *err == -EINPROGRESS)
809 		return s;
810 
811 	return rfcomm_session_del(s);
812 
813 failed:
814 	sock_release(sock);
815 	return NULL;
816 }
817 
818 void rfcomm_session_getaddr(struct rfcomm_session *s, bdaddr_t *src, bdaddr_t *dst)
819 {
820 	struct l2cap_chan *chan = l2cap_pi(s->sock->sk)->chan;
821 	if (src)
822 		bacpy(src, &chan->src);
823 	if (dst)
824 		bacpy(dst, &chan->dst);
825 }
826 
827 /* ---- RFCOMM frame sending ---- */
828 static int rfcomm_send_frame(struct rfcomm_session *s, u8 *data, int len)
829 {
830 	struct kvec iv = { data, len };
831 	struct msghdr msg;
832 
833 	BT_DBG("session %p len %d", s, len);
834 
835 	memset(&msg, 0, sizeof(msg));
836 
837 	return kernel_sendmsg(s->sock, &msg, &iv, 1, len);
838 }
839 
840 static int rfcomm_send_cmd(struct rfcomm_session *s, struct rfcomm_cmd *cmd)
841 {
842 	BT_DBG("%p cmd %u", s, cmd->ctrl);
843 
844 	return rfcomm_send_frame(s, (void *) cmd, sizeof(*cmd));
845 }
846 
847 static int rfcomm_send_sabm(struct rfcomm_session *s, u8 dlci)
848 {
849 	struct rfcomm_cmd cmd;
850 
851 	BT_DBG("%p dlci %d", s, dlci);
852 
853 	cmd.addr = __addr(s->initiator, dlci);
854 	cmd.ctrl = __ctrl(RFCOMM_SABM, 1);
855 	cmd.len  = __len8(0);
856 	cmd.fcs  = __fcs2((u8 *) &cmd);
857 
858 	return rfcomm_send_cmd(s, &cmd);
859 }
860 
861 static int rfcomm_send_ua(struct rfcomm_session *s, u8 dlci)
862 {
863 	struct rfcomm_cmd cmd;
864 
865 	BT_DBG("%p dlci %d", s, dlci);
866 
867 	cmd.addr = __addr(!s->initiator, dlci);
868 	cmd.ctrl = __ctrl(RFCOMM_UA, 1);
869 	cmd.len  = __len8(0);
870 	cmd.fcs  = __fcs2((u8 *) &cmd);
871 
872 	return rfcomm_send_cmd(s, &cmd);
873 }
874 
875 static int rfcomm_send_disc(struct rfcomm_session *s, u8 dlci)
876 {
877 	struct rfcomm_cmd cmd;
878 
879 	BT_DBG("%p dlci %d", s, dlci);
880 
881 	cmd.addr = __addr(s->initiator, dlci);
882 	cmd.ctrl = __ctrl(RFCOMM_DISC, 1);
883 	cmd.len  = __len8(0);
884 	cmd.fcs  = __fcs2((u8 *) &cmd);
885 
886 	return rfcomm_send_cmd(s, &cmd);
887 }
888 
889 static int rfcomm_queue_disc(struct rfcomm_dlc *d)
890 {
891 	struct rfcomm_cmd *cmd;
892 	struct sk_buff *skb;
893 
894 	BT_DBG("dlc %p dlci %d", d, d->dlci);
895 
896 	skb = alloc_skb(sizeof(*cmd), GFP_KERNEL);
897 	if (!skb)
898 		return -ENOMEM;
899 
900 	cmd = __skb_put(skb, sizeof(*cmd));
901 	cmd->addr = d->addr;
902 	cmd->ctrl = __ctrl(RFCOMM_DISC, 1);
903 	cmd->len  = __len8(0);
904 	cmd->fcs  = __fcs2((u8 *) cmd);
905 
906 	skb_queue_tail(&d->tx_queue, skb);
907 	rfcomm_schedule();
908 	return 0;
909 }
910 
911 static int rfcomm_send_dm(struct rfcomm_session *s, u8 dlci)
912 {
913 	struct rfcomm_cmd cmd;
914 
915 	BT_DBG("%p dlci %d", s, dlci);
916 
917 	cmd.addr = __addr(!s->initiator, dlci);
918 	cmd.ctrl = __ctrl(RFCOMM_DM, 1);
919 	cmd.len  = __len8(0);
920 	cmd.fcs  = __fcs2((u8 *) &cmd);
921 
922 	return rfcomm_send_cmd(s, &cmd);
923 }
924 
925 static int rfcomm_send_nsc(struct rfcomm_session *s, int cr, u8 type)
926 {
927 	struct rfcomm_hdr *hdr;
928 	struct rfcomm_mcc *mcc;
929 	u8 buf[16], *ptr = buf;
930 
931 	BT_DBG("%p cr %d type %d", s, cr, type);
932 
933 	hdr = (void *) ptr; ptr += sizeof(*hdr);
934 	hdr->addr = __addr(s->initiator, 0);
935 	hdr->ctrl = __ctrl(RFCOMM_UIH, 0);
936 	hdr->len  = __len8(sizeof(*mcc) + 1);
937 
938 	mcc = (void *) ptr; ptr += sizeof(*mcc);
939 	mcc->type = __mcc_type(0, RFCOMM_NSC);
940 	mcc->len  = __len8(1);
941 
942 	/* Type that we didn't like */
943 	*ptr = __mcc_type(cr, type); ptr++;
944 
945 	*ptr = __fcs(buf); ptr++;
946 
947 	return rfcomm_send_frame(s, buf, ptr - buf);
948 }
949 
950 static int rfcomm_send_pn(struct rfcomm_session *s, int cr, struct rfcomm_dlc *d)
951 {
952 	struct rfcomm_hdr *hdr;
953 	struct rfcomm_mcc *mcc;
954 	struct rfcomm_pn  *pn;
955 	u8 buf[16], *ptr = buf;
956 
957 	BT_DBG("%p cr %d dlci %d mtu %d", s, cr, d->dlci, d->mtu);
958 
959 	hdr = (void *) ptr; ptr += sizeof(*hdr);
960 	hdr->addr = __addr(s->initiator, 0);
961 	hdr->ctrl = __ctrl(RFCOMM_UIH, 0);
962 	hdr->len  = __len8(sizeof(*mcc) + sizeof(*pn));
963 
964 	mcc = (void *) ptr; ptr += sizeof(*mcc);
965 	mcc->type = __mcc_type(cr, RFCOMM_PN);
966 	mcc->len  = __len8(sizeof(*pn));
967 
968 	pn = (void *) ptr; ptr += sizeof(*pn);
969 	pn->dlci        = d->dlci;
970 	pn->priority    = d->priority;
971 	pn->ack_timer   = 0;
972 	pn->max_retrans = 0;
973 
974 	if (s->cfc) {
975 		pn->flow_ctrl = cr ? 0xf0 : 0xe0;
976 		pn->credits = RFCOMM_DEFAULT_CREDITS;
977 	} else {
978 		pn->flow_ctrl = 0;
979 		pn->credits   = 0;
980 	}
981 
982 	if (cr && channel_mtu >= 0)
983 		pn->mtu = cpu_to_le16(channel_mtu);
984 	else
985 		pn->mtu = cpu_to_le16(d->mtu);
986 
987 	*ptr = __fcs(buf); ptr++;
988 
989 	return rfcomm_send_frame(s, buf, ptr - buf);
990 }
991 
992 int rfcomm_send_rpn(struct rfcomm_session *s, int cr, u8 dlci,
993 			u8 bit_rate, u8 data_bits, u8 stop_bits,
994 			u8 parity, u8 flow_ctrl_settings,
995 			u8 xon_char, u8 xoff_char, u16 param_mask)
996 {
997 	struct rfcomm_hdr *hdr;
998 	struct rfcomm_mcc *mcc;
999 	struct rfcomm_rpn *rpn;
1000 	u8 buf[16], *ptr = buf;
1001 
1002 	BT_DBG("%p cr %d dlci %d bit_r 0x%x data_b 0x%x stop_b 0x%x parity 0x%x"
1003 			" flwc_s 0x%x xon_c 0x%x xoff_c 0x%x p_mask 0x%x",
1004 		s, cr, dlci, bit_rate, data_bits, stop_bits, parity,
1005 		flow_ctrl_settings, xon_char, xoff_char, param_mask);
1006 
1007 	hdr = (void *) ptr; ptr += sizeof(*hdr);
1008 	hdr->addr = __addr(s->initiator, 0);
1009 	hdr->ctrl = __ctrl(RFCOMM_UIH, 0);
1010 	hdr->len  = __len8(sizeof(*mcc) + sizeof(*rpn));
1011 
1012 	mcc = (void *) ptr; ptr += sizeof(*mcc);
1013 	mcc->type = __mcc_type(cr, RFCOMM_RPN);
1014 	mcc->len  = __len8(sizeof(*rpn));
1015 
1016 	rpn = (void *) ptr; ptr += sizeof(*rpn);
1017 	rpn->dlci          = __addr(1, dlci);
1018 	rpn->bit_rate      = bit_rate;
1019 	rpn->line_settings = __rpn_line_settings(data_bits, stop_bits, parity);
1020 	rpn->flow_ctrl     = flow_ctrl_settings;
1021 	rpn->xon_char      = xon_char;
1022 	rpn->xoff_char     = xoff_char;
1023 	rpn->param_mask    = cpu_to_le16(param_mask);
1024 
1025 	*ptr = __fcs(buf); ptr++;
1026 
1027 	return rfcomm_send_frame(s, buf, ptr - buf);
1028 }
1029 
1030 static int rfcomm_send_rls(struct rfcomm_session *s, int cr, u8 dlci, u8 status)
1031 {
1032 	struct rfcomm_hdr *hdr;
1033 	struct rfcomm_mcc *mcc;
1034 	struct rfcomm_rls *rls;
1035 	u8 buf[16], *ptr = buf;
1036 
1037 	BT_DBG("%p cr %d status 0x%x", s, cr, status);
1038 
1039 	hdr = (void *) ptr; ptr += sizeof(*hdr);
1040 	hdr->addr = __addr(s->initiator, 0);
1041 	hdr->ctrl = __ctrl(RFCOMM_UIH, 0);
1042 	hdr->len  = __len8(sizeof(*mcc) + sizeof(*rls));
1043 
1044 	mcc = (void *) ptr; ptr += sizeof(*mcc);
1045 	mcc->type = __mcc_type(cr, RFCOMM_RLS);
1046 	mcc->len  = __len8(sizeof(*rls));
1047 
1048 	rls = (void *) ptr; ptr += sizeof(*rls);
1049 	rls->dlci   = __addr(1, dlci);
1050 	rls->status = status;
1051 
1052 	*ptr = __fcs(buf); ptr++;
1053 
1054 	return rfcomm_send_frame(s, buf, ptr - buf);
1055 }
1056 
1057 static int rfcomm_send_msc(struct rfcomm_session *s, int cr, u8 dlci, u8 v24_sig)
1058 {
1059 	struct rfcomm_hdr *hdr;
1060 	struct rfcomm_mcc *mcc;
1061 	struct rfcomm_msc *msc;
1062 	u8 buf[16], *ptr = buf;
1063 
1064 	BT_DBG("%p cr %d v24 0x%x", s, cr, v24_sig);
1065 
1066 	hdr = (void *) ptr; ptr += sizeof(*hdr);
1067 	hdr->addr = __addr(s->initiator, 0);
1068 	hdr->ctrl = __ctrl(RFCOMM_UIH, 0);
1069 	hdr->len  = __len8(sizeof(*mcc) + sizeof(*msc));
1070 
1071 	mcc = (void *) ptr; ptr += sizeof(*mcc);
1072 	mcc->type = __mcc_type(cr, RFCOMM_MSC);
1073 	mcc->len  = __len8(sizeof(*msc));
1074 
1075 	msc = (void *) ptr; ptr += sizeof(*msc);
1076 	msc->dlci    = __addr(1, dlci);
1077 	msc->v24_sig = v24_sig | 0x01;
1078 
1079 	*ptr = __fcs(buf); ptr++;
1080 
1081 	return rfcomm_send_frame(s, buf, ptr - buf);
1082 }
1083 
1084 static int rfcomm_send_fcoff(struct rfcomm_session *s, int cr)
1085 {
1086 	struct rfcomm_hdr *hdr;
1087 	struct rfcomm_mcc *mcc;
1088 	u8 buf[16], *ptr = buf;
1089 
1090 	BT_DBG("%p cr %d", s, cr);
1091 
1092 	hdr = (void *) ptr; ptr += sizeof(*hdr);
1093 	hdr->addr = __addr(s->initiator, 0);
1094 	hdr->ctrl = __ctrl(RFCOMM_UIH, 0);
1095 	hdr->len  = __len8(sizeof(*mcc));
1096 
1097 	mcc = (void *) ptr; ptr += sizeof(*mcc);
1098 	mcc->type = __mcc_type(cr, RFCOMM_FCOFF);
1099 	mcc->len  = __len8(0);
1100 
1101 	*ptr = __fcs(buf); ptr++;
1102 
1103 	return rfcomm_send_frame(s, buf, ptr - buf);
1104 }
1105 
1106 static int rfcomm_send_fcon(struct rfcomm_session *s, int cr)
1107 {
1108 	struct rfcomm_hdr *hdr;
1109 	struct rfcomm_mcc *mcc;
1110 	u8 buf[16], *ptr = buf;
1111 
1112 	BT_DBG("%p cr %d", s, cr);
1113 
1114 	hdr = (void *) ptr; ptr += sizeof(*hdr);
1115 	hdr->addr = __addr(s->initiator, 0);
1116 	hdr->ctrl = __ctrl(RFCOMM_UIH, 0);
1117 	hdr->len  = __len8(sizeof(*mcc));
1118 
1119 	mcc = (void *) ptr; ptr += sizeof(*mcc);
1120 	mcc->type = __mcc_type(cr, RFCOMM_FCON);
1121 	mcc->len  = __len8(0);
1122 
1123 	*ptr = __fcs(buf); ptr++;
1124 
1125 	return rfcomm_send_frame(s, buf, ptr - buf);
1126 }
1127 
1128 static int rfcomm_send_test(struct rfcomm_session *s, int cr, u8 *pattern, int len)
1129 {
1130 	struct socket *sock = s->sock;
1131 	struct kvec iv[3];
1132 	struct msghdr msg;
1133 	unsigned char hdr[5], crc[1];
1134 
1135 	if (len > 125)
1136 		return -EINVAL;
1137 
1138 	BT_DBG("%p cr %d", s, cr);
1139 
1140 	hdr[0] = __addr(s->initiator, 0);
1141 	hdr[1] = __ctrl(RFCOMM_UIH, 0);
1142 	hdr[2] = 0x01 | ((len + 2) << 1);
1143 	hdr[3] = 0x01 | ((cr & 0x01) << 1) | (RFCOMM_TEST << 2);
1144 	hdr[4] = 0x01 | (len << 1);
1145 
1146 	crc[0] = __fcs(hdr);
1147 
1148 	iv[0].iov_base = hdr;
1149 	iv[0].iov_len  = 5;
1150 	iv[1].iov_base = pattern;
1151 	iv[1].iov_len  = len;
1152 	iv[2].iov_base = crc;
1153 	iv[2].iov_len  = 1;
1154 
1155 	memset(&msg, 0, sizeof(msg));
1156 
1157 	return kernel_sendmsg(sock, &msg, iv, 3, 6 + len);
1158 }
1159 
1160 static int rfcomm_send_credits(struct rfcomm_session *s, u8 addr, u8 credits)
1161 {
1162 	struct rfcomm_hdr *hdr;
1163 	u8 buf[16], *ptr = buf;
1164 
1165 	BT_DBG("%p addr %d credits %d", s, addr, credits);
1166 
1167 	hdr = (void *) ptr; ptr += sizeof(*hdr);
1168 	hdr->addr = addr;
1169 	hdr->ctrl = __ctrl(RFCOMM_UIH, 1);
1170 	hdr->len  = __len8(0);
1171 
1172 	*ptr = credits; ptr++;
1173 
1174 	*ptr = __fcs(buf); ptr++;
1175 
1176 	return rfcomm_send_frame(s, buf, ptr - buf);
1177 }
1178 
1179 static void rfcomm_make_uih(struct sk_buff *skb, u8 addr)
1180 {
1181 	struct rfcomm_hdr *hdr;
1182 	int len = skb->len;
1183 	u8 *crc;
1184 
1185 	if (len > 127) {
1186 		hdr = skb_push(skb, 4);
1187 		put_unaligned(cpu_to_le16(__len16(len)), (__le16 *) &hdr->len);
1188 	} else {
1189 		hdr = skb_push(skb, 3);
1190 		hdr->len = __len8(len);
1191 	}
1192 	hdr->addr = addr;
1193 	hdr->ctrl = __ctrl(RFCOMM_UIH, 0);
1194 
1195 	crc = skb_put(skb, 1);
1196 	*crc = __fcs((void *) hdr);
1197 }
1198 
1199 /* ---- RFCOMM frame reception ---- */
1200 static struct rfcomm_session *rfcomm_recv_ua(struct rfcomm_session *s, u8 dlci)
1201 {
1202 	BT_DBG("session %p state %ld dlci %d", s, s->state, dlci);
1203 
1204 	if (dlci) {
1205 		/* Data channel */
1206 		struct rfcomm_dlc *d = rfcomm_dlc_get(s, dlci);
1207 		if (!d) {
1208 			rfcomm_send_dm(s, dlci);
1209 			return s;
1210 		}
1211 
1212 		switch (d->state) {
1213 		case BT_CONNECT:
1214 			rfcomm_dlc_clear_timer(d);
1215 
1216 			rfcomm_dlc_lock(d);
1217 			d->state = BT_CONNECTED;
1218 			d->state_change(d, 0);
1219 			rfcomm_dlc_unlock(d);
1220 
1221 			rfcomm_send_msc(s, 1, dlci, d->v24_sig);
1222 			break;
1223 
1224 		case BT_DISCONN:
1225 			d->state = BT_CLOSED;
1226 			__rfcomm_dlc_close(d, 0);
1227 
1228 			if (list_empty(&s->dlcs)) {
1229 				s->state = BT_DISCONN;
1230 				rfcomm_send_disc(s, 0);
1231 				rfcomm_session_clear_timer(s);
1232 			}
1233 
1234 			break;
1235 		}
1236 	} else {
1237 		/* Control channel */
1238 		switch (s->state) {
1239 		case BT_CONNECT:
1240 			s->state = BT_CONNECTED;
1241 			rfcomm_process_connect(s);
1242 			break;
1243 
1244 		case BT_DISCONN:
1245 			s = rfcomm_session_close(s, ECONNRESET);
1246 			break;
1247 		}
1248 	}
1249 	return s;
1250 }
1251 
1252 static struct rfcomm_session *rfcomm_recv_dm(struct rfcomm_session *s, u8 dlci)
1253 {
1254 	int err = 0;
1255 
1256 	BT_DBG("session %p state %ld dlci %d", s, s->state, dlci);
1257 
1258 	if (dlci) {
1259 		/* Data DLC */
1260 		struct rfcomm_dlc *d = rfcomm_dlc_get(s, dlci);
1261 		if (d) {
1262 			if (d->state == BT_CONNECT || d->state == BT_CONFIG)
1263 				err = ECONNREFUSED;
1264 			else
1265 				err = ECONNRESET;
1266 
1267 			d->state = BT_CLOSED;
1268 			__rfcomm_dlc_close(d, err);
1269 		}
1270 	} else {
1271 		if (s->state == BT_CONNECT)
1272 			err = ECONNREFUSED;
1273 		else
1274 			err = ECONNRESET;
1275 
1276 		s = rfcomm_session_close(s, err);
1277 	}
1278 	return s;
1279 }
1280 
1281 static struct rfcomm_session *rfcomm_recv_disc(struct rfcomm_session *s,
1282 					       u8 dlci)
1283 {
1284 	int err = 0;
1285 
1286 	BT_DBG("session %p state %ld dlci %d", s, s->state, dlci);
1287 
1288 	if (dlci) {
1289 		struct rfcomm_dlc *d = rfcomm_dlc_get(s, dlci);
1290 		if (d) {
1291 			rfcomm_send_ua(s, dlci);
1292 
1293 			if (d->state == BT_CONNECT || d->state == BT_CONFIG)
1294 				err = ECONNREFUSED;
1295 			else
1296 				err = ECONNRESET;
1297 
1298 			d->state = BT_CLOSED;
1299 			__rfcomm_dlc_close(d, err);
1300 		} else
1301 			rfcomm_send_dm(s, dlci);
1302 
1303 	} else {
1304 		rfcomm_send_ua(s, 0);
1305 
1306 		if (s->state == BT_CONNECT)
1307 			err = ECONNREFUSED;
1308 		else
1309 			err = ECONNRESET;
1310 
1311 		s = rfcomm_session_close(s, err);
1312 	}
1313 	return s;
1314 }
1315 
1316 void rfcomm_dlc_accept(struct rfcomm_dlc *d)
1317 {
1318 	struct sock *sk = d->session->sock->sk;
1319 	struct l2cap_conn *conn = l2cap_pi(sk)->chan->conn;
1320 
1321 	BT_DBG("dlc %p", d);
1322 
1323 	rfcomm_send_ua(d->session, d->dlci);
1324 
1325 	rfcomm_dlc_clear_timer(d);
1326 
1327 	rfcomm_dlc_lock(d);
1328 	d->state = BT_CONNECTED;
1329 	d->state_change(d, 0);
1330 	rfcomm_dlc_unlock(d);
1331 
1332 	if (d->role_switch)
1333 		hci_conn_switch_role(conn->hcon, 0x00);
1334 
1335 	rfcomm_send_msc(d->session, 1, d->dlci, d->v24_sig);
1336 }
1337 
1338 static void rfcomm_check_accept(struct rfcomm_dlc *d)
1339 {
1340 	if (rfcomm_check_security(d)) {
1341 		if (d->defer_setup) {
1342 			set_bit(RFCOMM_DEFER_SETUP, &d->flags);
1343 			rfcomm_dlc_set_timer(d, RFCOMM_AUTH_TIMEOUT);
1344 
1345 			rfcomm_dlc_lock(d);
1346 			d->state = BT_CONNECT2;
1347 			d->state_change(d, 0);
1348 			rfcomm_dlc_unlock(d);
1349 		} else
1350 			rfcomm_dlc_accept(d);
1351 	} else {
1352 		set_bit(RFCOMM_AUTH_PENDING, &d->flags);
1353 		rfcomm_dlc_set_timer(d, RFCOMM_AUTH_TIMEOUT);
1354 	}
1355 }
1356 
1357 static int rfcomm_recv_sabm(struct rfcomm_session *s, u8 dlci)
1358 {
1359 	struct rfcomm_dlc *d;
1360 	u8 channel;
1361 
1362 	BT_DBG("session %p state %ld dlci %d", s, s->state, dlci);
1363 
1364 	if (!dlci) {
1365 		rfcomm_send_ua(s, 0);
1366 
1367 		if (s->state == BT_OPEN) {
1368 			s->state = BT_CONNECTED;
1369 			rfcomm_process_connect(s);
1370 		}
1371 		return 0;
1372 	}
1373 
1374 	/* Check if DLC exists */
1375 	d = rfcomm_dlc_get(s, dlci);
1376 	if (d) {
1377 		if (d->state == BT_OPEN) {
1378 			/* DLC was previously opened by PN request */
1379 			rfcomm_check_accept(d);
1380 		}
1381 		return 0;
1382 	}
1383 
1384 	/* Notify socket layer about incoming connection */
1385 	channel = __srv_channel(dlci);
1386 	if (rfcomm_connect_ind(s, channel, &d)) {
1387 		d->dlci = dlci;
1388 		d->addr = __addr(s->initiator, dlci);
1389 		rfcomm_dlc_link(s, d);
1390 
1391 		rfcomm_check_accept(d);
1392 	} else {
1393 		rfcomm_send_dm(s, dlci);
1394 	}
1395 
1396 	return 0;
1397 }
1398 
1399 static int rfcomm_apply_pn(struct rfcomm_dlc *d, int cr, struct rfcomm_pn *pn)
1400 {
1401 	struct rfcomm_session *s = d->session;
1402 
1403 	BT_DBG("dlc %p state %ld dlci %d mtu %d fc 0x%x credits %d",
1404 			d, d->state, d->dlci, pn->mtu, pn->flow_ctrl, pn->credits);
1405 
1406 	if ((pn->flow_ctrl == 0xf0 && s->cfc != RFCOMM_CFC_DISABLED) ||
1407 						pn->flow_ctrl == 0xe0) {
1408 		d->cfc = RFCOMM_CFC_ENABLED;
1409 		d->tx_credits = pn->credits;
1410 	} else {
1411 		d->cfc = RFCOMM_CFC_DISABLED;
1412 		set_bit(RFCOMM_TX_THROTTLED, &d->flags);
1413 	}
1414 
1415 	if (s->cfc == RFCOMM_CFC_UNKNOWN)
1416 		s->cfc = d->cfc;
1417 
1418 	d->priority = pn->priority;
1419 
1420 	d->mtu = __le16_to_cpu(pn->mtu);
1421 
1422 	if (cr && d->mtu > s->mtu)
1423 		d->mtu = s->mtu;
1424 
1425 	return 0;
1426 }
1427 
1428 static int rfcomm_recv_pn(struct rfcomm_session *s, int cr, struct sk_buff *skb)
1429 {
1430 	struct rfcomm_pn *pn = (void *) skb->data;
1431 	struct rfcomm_dlc *d;
1432 	u8 dlci = pn->dlci;
1433 
1434 	BT_DBG("session %p state %ld dlci %d", s, s->state, dlci);
1435 
1436 	if (!dlci)
1437 		return 0;
1438 
1439 	d = rfcomm_dlc_get(s, dlci);
1440 	if (d) {
1441 		if (cr) {
1442 			/* PN request */
1443 			rfcomm_apply_pn(d, cr, pn);
1444 			rfcomm_send_pn(s, 0, d);
1445 		} else {
1446 			/* PN response */
1447 			switch (d->state) {
1448 			case BT_CONFIG:
1449 				rfcomm_apply_pn(d, cr, pn);
1450 
1451 				d->state = BT_CONNECT;
1452 				rfcomm_send_sabm(s, d->dlci);
1453 				break;
1454 			}
1455 		}
1456 	} else {
1457 		u8 channel = __srv_channel(dlci);
1458 
1459 		if (!cr)
1460 			return 0;
1461 
1462 		/* PN request for non existing DLC.
1463 		 * Assume incoming connection. */
1464 		if (rfcomm_connect_ind(s, channel, &d)) {
1465 			d->dlci = dlci;
1466 			d->addr = __addr(s->initiator, dlci);
1467 			rfcomm_dlc_link(s, d);
1468 
1469 			rfcomm_apply_pn(d, cr, pn);
1470 
1471 			d->state = BT_OPEN;
1472 			rfcomm_send_pn(s, 0, d);
1473 		} else {
1474 			rfcomm_send_dm(s, dlci);
1475 		}
1476 	}
1477 	return 0;
1478 }
1479 
1480 static int rfcomm_recv_rpn(struct rfcomm_session *s, int cr, int len, struct sk_buff *skb)
1481 {
1482 	struct rfcomm_rpn *rpn = (void *) skb->data;
1483 	u8 dlci = __get_dlci(rpn->dlci);
1484 
1485 	u8 bit_rate  = 0;
1486 	u8 data_bits = 0;
1487 	u8 stop_bits = 0;
1488 	u8 parity    = 0;
1489 	u8 flow_ctrl = 0;
1490 	u8 xon_char  = 0;
1491 	u8 xoff_char = 0;
1492 	u16 rpn_mask = RFCOMM_RPN_PM_ALL;
1493 
1494 	BT_DBG("dlci %d cr %d len 0x%x bitr 0x%x line 0x%x flow 0x%x xonc 0x%x xoffc 0x%x pm 0x%x",
1495 		dlci, cr, len, rpn->bit_rate, rpn->line_settings, rpn->flow_ctrl,
1496 		rpn->xon_char, rpn->xoff_char, rpn->param_mask);
1497 
1498 	if (!cr)
1499 		return 0;
1500 
1501 	if (len == 1) {
1502 		/* This is a request, return default (according to ETSI TS 07.10) settings */
1503 		bit_rate  = RFCOMM_RPN_BR_9600;
1504 		data_bits = RFCOMM_RPN_DATA_8;
1505 		stop_bits = RFCOMM_RPN_STOP_1;
1506 		parity    = RFCOMM_RPN_PARITY_NONE;
1507 		flow_ctrl = RFCOMM_RPN_FLOW_NONE;
1508 		xon_char  = RFCOMM_RPN_XON_CHAR;
1509 		xoff_char = RFCOMM_RPN_XOFF_CHAR;
1510 		goto rpn_out;
1511 	}
1512 
1513 	/* Check for sane values, ignore/accept bit_rate, 8 bits, 1 stop bit,
1514 	 * no parity, no flow control lines, normal XON/XOFF chars */
1515 
1516 	if (rpn->param_mask & cpu_to_le16(RFCOMM_RPN_PM_BITRATE)) {
1517 		bit_rate = rpn->bit_rate;
1518 		if (bit_rate > RFCOMM_RPN_BR_230400) {
1519 			BT_DBG("RPN bit rate mismatch 0x%x", bit_rate);
1520 			bit_rate = RFCOMM_RPN_BR_9600;
1521 			rpn_mask ^= RFCOMM_RPN_PM_BITRATE;
1522 		}
1523 	}
1524 
1525 	if (rpn->param_mask & cpu_to_le16(RFCOMM_RPN_PM_DATA)) {
1526 		data_bits = __get_rpn_data_bits(rpn->line_settings);
1527 		if (data_bits != RFCOMM_RPN_DATA_8) {
1528 			BT_DBG("RPN data bits mismatch 0x%x", data_bits);
1529 			data_bits = RFCOMM_RPN_DATA_8;
1530 			rpn_mask ^= RFCOMM_RPN_PM_DATA;
1531 		}
1532 	}
1533 
1534 	if (rpn->param_mask & cpu_to_le16(RFCOMM_RPN_PM_STOP)) {
1535 		stop_bits = __get_rpn_stop_bits(rpn->line_settings);
1536 		if (stop_bits != RFCOMM_RPN_STOP_1) {
1537 			BT_DBG("RPN stop bits mismatch 0x%x", stop_bits);
1538 			stop_bits = RFCOMM_RPN_STOP_1;
1539 			rpn_mask ^= RFCOMM_RPN_PM_STOP;
1540 		}
1541 	}
1542 
1543 	if (rpn->param_mask & cpu_to_le16(RFCOMM_RPN_PM_PARITY)) {
1544 		parity = __get_rpn_parity(rpn->line_settings);
1545 		if (parity != RFCOMM_RPN_PARITY_NONE) {
1546 			BT_DBG("RPN parity mismatch 0x%x", parity);
1547 			parity = RFCOMM_RPN_PARITY_NONE;
1548 			rpn_mask ^= RFCOMM_RPN_PM_PARITY;
1549 		}
1550 	}
1551 
1552 	if (rpn->param_mask & cpu_to_le16(RFCOMM_RPN_PM_FLOW)) {
1553 		flow_ctrl = rpn->flow_ctrl;
1554 		if (flow_ctrl != RFCOMM_RPN_FLOW_NONE) {
1555 			BT_DBG("RPN flow ctrl mismatch 0x%x", flow_ctrl);
1556 			flow_ctrl = RFCOMM_RPN_FLOW_NONE;
1557 			rpn_mask ^= RFCOMM_RPN_PM_FLOW;
1558 		}
1559 	}
1560 
1561 	if (rpn->param_mask & cpu_to_le16(RFCOMM_RPN_PM_XON)) {
1562 		xon_char = rpn->xon_char;
1563 		if (xon_char != RFCOMM_RPN_XON_CHAR) {
1564 			BT_DBG("RPN XON char mismatch 0x%x", xon_char);
1565 			xon_char = RFCOMM_RPN_XON_CHAR;
1566 			rpn_mask ^= RFCOMM_RPN_PM_XON;
1567 		}
1568 	}
1569 
1570 	if (rpn->param_mask & cpu_to_le16(RFCOMM_RPN_PM_XOFF)) {
1571 		xoff_char = rpn->xoff_char;
1572 		if (xoff_char != RFCOMM_RPN_XOFF_CHAR) {
1573 			BT_DBG("RPN XOFF char mismatch 0x%x", xoff_char);
1574 			xoff_char = RFCOMM_RPN_XOFF_CHAR;
1575 			rpn_mask ^= RFCOMM_RPN_PM_XOFF;
1576 		}
1577 	}
1578 
1579 rpn_out:
1580 	rfcomm_send_rpn(s, 0, dlci, bit_rate, data_bits, stop_bits,
1581 			parity, flow_ctrl, xon_char, xoff_char, rpn_mask);
1582 
1583 	return 0;
1584 }
1585 
1586 static int rfcomm_recv_rls(struct rfcomm_session *s, int cr, struct sk_buff *skb)
1587 {
1588 	struct rfcomm_rls *rls = (void *) skb->data;
1589 	u8 dlci = __get_dlci(rls->dlci);
1590 
1591 	BT_DBG("dlci %d cr %d status 0x%x", dlci, cr, rls->status);
1592 
1593 	if (!cr)
1594 		return 0;
1595 
1596 	/* We should probably do something with this information here. But
1597 	 * for now it's sufficient just to reply -- Bluetooth 1.1 says it's
1598 	 * mandatory to recognise and respond to RLS */
1599 
1600 	rfcomm_send_rls(s, 0, dlci, rls->status);
1601 
1602 	return 0;
1603 }
1604 
1605 static int rfcomm_recv_msc(struct rfcomm_session *s, int cr, struct sk_buff *skb)
1606 {
1607 	struct rfcomm_msc *msc = (void *) skb->data;
1608 	struct rfcomm_dlc *d;
1609 	u8 dlci = __get_dlci(msc->dlci);
1610 
1611 	BT_DBG("dlci %d cr %d v24 0x%x", dlci, cr, msc->v24_sig);
1612 
1613 	d = rfcomm_dlc_get(s, dlci);
1614 	if (!d)
1615 		return 0;
1616 
1617 	if (cr) {
1618 		if (msc->v24_sig & RFCOMM_V24_FC && !d->cfc)
1619 			set_bit(RFCOMM_TX_THROTTLED, &d->flags);
1620 		else
1621 			clear_bit(RFCOMM_TX_THROTTLED, &d->flags);
1622 
1623 		rfcomm_dlc_lock(d);
1624 
1625 		d->remote_v24_sig = msc->v24_sig;
1626 
1627 		if (d->modem_status)
1628 			d->modem_status(d, msc->v24_sig);
1629 
1630 		rfcomm_dlc_unlock(d);
1631 
1632 		rfcomm_send_msc(s, 0, dlci, msc->v24_sig);
1633 
1634 		d->mscex |= RFCOMM_MSCEX_RX;
1635 	} else
1636 		d->mscex |= RFCOMM_MSCEX_TX;
1637 
1638 	return 0;
1639 }
1640 
1641 static int rfcomm_recv_mcc(struct rfcomm_session *s, struct sk_buff *skb)
1642 {
1643 	struct rfcomm_mcc *mcc = (void *) skb->data;
1644 	u8 type, cr, len;
1645 
1646 	cr   = __test_cr(mcc->type);
1647 	type = __get_mcc_type(mcc->type);
1648 	len  = __get_mcc_len(mcc->len);
1649 
1650 	BT_DBG("%p type 0x%x cr %d", s, type, cr);
1651 
1652 	skb_pull(skb, 2);
1653 
1654 	switch (type) {
1655 	case RFCOMM_PN:
1656 		rfcomm_recv_pn(s, cr, skb);
1657 		break;
1658 
1659 	case RFCOMM_RPN:
1660 		rfcomm_recv_rpn(s, cr, len, skb);
1661 		break;
1662 
1663 	case RFCOMM_RLS:
1664 		rfcomm_recv_rls(s, cr, skb);
1665 		break;
1666 
1667 	case RFCOMM_MSC:
1668 		rfcomm_recv_msc(s, cr, skb);
1669 		break;
1670 
1671 	case RFCOMM_FCOFF:
1672 		if (cr) {
1673 			set_bit(RFCOMM_TX_THROTTLED, &s->flags);
1674 			rfcomm_send_fcoff(s, 0);
1675 		}
1676 		break;
1677 
1678 	case RFCOMM_FCON:
1679 		if (cr) {
1680 			clear_bit(RFCOMM_TX_THROTTLED, &s->flags);
1681 			rfcomm_send_fcon(s, 0);
1682 		}
1683 		break;
1684 
1685 	case RFCOMM_TEST:
1686 		if (cr)
1687 			rfcomm_send_test(s, 0, skb->data, skb->len);
1688 		break;
1689 
1690 	case RFCOMM_NSC:
1691 		break;
1692 
1693 	default:
1694 		BT_ERR("Unknown control type 0x%02x", type);
1695 		rfcomm_send_nsc(s, cr, type);
1696 		break;
1697 	}
1698 	return 0;
1699 }
1700 
1701 static int rfcomm_recv_data(struct rfcomm_session *s, u8 dlci, int pf, struct sk_buff *skb)
1702 {
1703 	struct rfcomm_dlc *d;
1704 
1705 	BT_DBG("session %p state %ld dlci %d pf %d", s, s->state, dlci, pf);
1706 
1707 	d = rfcomm_dlc_get(s, dlci);
1708 	if (!d) {
1709 		rfcomm_send_dm(s, dlci);
1710 		goto drop;
1711 	}
1712 
1713 	if (pf && d->cfc) {
1714 		u8 credits = *(u8 *) skb->data; skb_pull(skb, 1);
1715 
1716 		d->tx_credits += credits;
1717 		if (d->tx_credits)
1718 			clear_bit(RFCOMM_TX_THROTTLED, &d->flags);
1719 	}
1720 
1721 	if (skb->len && d->state == BT_CONNECTED) {
1722 		rfcomm_dlc_lock(d);
1723 		d->rx_credits--;
1724 		d->data_ready(d, skb);
1725 		rfcomm_dlc_unlock(d);
1726 		return 0;
1727 	}
1728 
1729 drop:
1730 	kfree_skb(skb);
1731 	return 0;
1732 }
1733 
1734 static struct rfcomm_session *rfcomm_recv_frame(struct rfcomm_session *s,
1735 						struct sk_buff *skb)
1736 {
1737 	struct rfcomm_hdr *hdr = (void *) skb->data;
1738 	u8 type, dlci, fcs;
1739 
1740 	if (!s) {
1741 		/* no session, so free socket data */
1742 		kfree_skb(skb);
1743 		return s;
1744 	}
1745 
1746 	dlci = __get_dlci(hdr->addr);
1747 	type = __get_type(hdr->ctrl);
1748 
1749 	/* Trim FCS */
1750 	skb->len--; skb->tail--;
1751 	fcs = *(u8 *)skb_tail_pointer(skb);
1752 
1753 	if (__check_fcs(skb->data, type, fcs)) {
1754 		BT_ERR("bad checksum in packet");
1755 		kfree_skb(skb);
1756 		return s;
1757 	}
1758 
1759 	if (__test_ea(hdr->len))
1760 		skb_pull(skb, 3);
1761 	else
1762 		skb_pull(skb, 4);
1763 
1764 	switch (type) {
1765 	case RFCOMM_SABM:
1766 		if (__test_pf(hdr->ctrl))
1767 			rfcomm_recv_sabm(s, dlci);
1768 		break;
1769 
1770 	case RFCOMM_DISC:
1771 		if (__test_pf(hdr->ctrl))
1772 			s = rfcomm_recv_disc(s, dlci);
1773 		break;
1774 
1775 	case RFCOMM_UA:
1776 		if (__test_pf(hdr->ctrl))
1777 			s = rfcomm_recv_ua(s, dlci);
1778 		break;
1779 
1780 	case RFCOMM_DM:
1781 		s = rfcomm_recv_dm(s, dlci);
1782 		break;
1783 
1784 	case RFCOMM_UIH:
1785 		if (dlci) {
1786 			rfcomm_recv_data(s, dlci, __test_pf(hdr->ctrl), skb);
1787 			return s;
1788 		}
1789 		rfcomm_recv_mcc(s, skb);
1790 		break;
1791 
1792 	default:
1793 		BT_ERR("Unknown packet type 0x%02x", type);
1794 		break;
1795 	}
1796 	kfree_skb(skb);
1797 	return s;
1798 }
1799 
1800 /* ---- Connection and data processing ---- */
1801 
1802 static void rfcomm_process_connect(struct rfcomm_session *s)
1803 {
1804 	struct rfcomm_dlc *d, *n;
1805 
1806 	BT_DBG("session %p state %ld", s, s->state);
1807 
1808 	list_for_each_entry_safe(d, n, &s->dlcs, list) {
1809 		if (d->state == BT_CONFIG) {
1810 			d->mtu = s->mtu;
1811 			if (rfcomm_check_security(d)) {
1812 				rfcomm_send_pn(s, 1, d);
1813 			} else {
1814 				set_bit(RFCOMM_AUTH_PENDING, &d->flags);
1815 				rfcomm_dlc_set_timer(d, RFCOMM_AUTH_TIMEOUT);
1816 			}
1817 		}
1818 	}
1819 }
1820 
1821 /* Send data queued for the DLC.
1822  * Return number of frames left in the queue.
1823  */
1824 static int rfcomm_process_tx(struct rfcomm_dlc *d)
1825 {
1826 	struct sk_buff *skb;
1827 	int err;
1828 
1829 	BT_DBG("dlc %p state %ld cfc %d rx_credits %d tx_credits %d",
1830 			d, d->state, d->cfc, d->rx_credits, d->tx_credits);
1831 
1832 	/* Send pending MSC */
1833 	if (test_and_clear_bit(RFCOMM_MSC_PENDING, &d->flags))
1834 		rfcomm_send_msc(d->session, 1, d->dlci, d->v24_sig);
1835 
1836 	if (d->cfc) {
1837 		/* CFC enabled.
1838 		 * Give them some credits */
1839 		if (!test_bit(RFCOMM_RX_THROTTLED, &d->flags) &&
1840 				d->rx_credits <= (d->cfc >> 2)) {
1841 			rfcomm_send_credits(d->session, d->addr, d->cfc - d->rx_credits);
1842 			d->rx_credits = d->cfc;
1843 		}
1844 	} else {
1845 		/* CFC disabled.
1846 		 * Give ourselves some credits */
1847 		d->tx_credits = 5;
1848 	}
1849 
1850 	if (test_bit(RFCOMM_TX_THROTTLED, &d->flags))
1851 		return skb_queue_len(&d->tx_queue);
1852 
1853 	while (d->tx_credits && (skb = skb_dequeue(&d->tx_queue))) {
1854 		err = rfcomm_send_frame(d->session, skb->data, skb->len);
1855 		if (err < 0) {
1856 			skb_queue_head(&d->tx_queue, skb);
1857 			break;
1858 		}
1859 		kfree_skb(skb);
1860 		d->tx_credits--;
1861 	}
1862 
1863 	if (d->cfc && !d->tx_credits) {
1864 		/* We're out of TX credits.
1865 		 * Set TX_THROTTLED flag to avoid unnesary wakeups by dlc_send. */
1866 		set_bit(RFCOMM_TX_THROTTLED, &d->flags);
1867 	}
1868 
1869 	return skb_queue_len(&d->tx_queue);
1870 }
1871 
1872 static void rfcomm_process_dlcs(struct rfcomm_session *s)
1873 {
1874 	struct rfcomm_dlc *d, *n;
1875 
1876 	BT_DBG("session %p state %ld", s, s->state);
1877 
1878 	list_for_each_entry_safe(d, n, &s->dlcs, list) {
1879 		if (test_bit(RFCOMM_TIMED_OUT, &d->flags)) {
1880 			__rfcomm_dlc_close(d, ETIMEDOUT);
1881 			continue;
1882 		}
1883 
1884 		if (test_bit(RFCOMM_ENC_DROP, &d->flags)) {
1885 			__rfcomm_dlc_close(d, ECONNREFUSED);
1886 			continue;
1887 		}
1888 
1889 		if (test_and_clear_bit(RFCOMM_AUTH_ACCEPT, &d->flags)) {
1890 			rfcomm_dlc_clear_timer(d);
1891 			if (d->out) {
1892 				rfcomm_send_pn(s, 1, d);
1893 				rfcomm_dlc_set_timer(d, RFCOMM_CONN_TIMEOUT);
1894 			} else {
1895 				if (d->defer_setup) {
1896 					set_bit(RFCOMM_DEFER_SETUP, &d->flags);
1897 					rfcomm_dlc_set_timer(d, RFCOMM_AUTH_TIMEOUT);
1898 
1899 					rfcomm_dlc_lock(d);
1900 					d->state = BT_CONNECT2;
1901 					d->state_change(d, 0);
1902 					rfcomm_dlc_unlock(d);
1903 				} else
1904 					rfcomm_dlc_accept(d);
1905 			}
1906 			continue;
1907 		} else if (test_and_clear_bit(RFCOMM_AUTH_REJECT, &d->flags)) {
1908 			rfcomm_dlc_clear_timer(d);
1909 			if (!d->out)
1910 				rfcomm_send_dm(s, d->dlci);
1911 			else
1912 				d->state = BT_CLOSED;
1913 			__rfcomm_dlc_close(d, ECONNREFUSED);
1914 			continue;
1915 		}
1916 
1917 		if (test_bit(RFCOMM_SEC_PENDING, &d->flags))
1918 			continue;
1919 
1920 		if (test_bit(RFCOMM_TX_THROTTLED, &s->flags))
1921 			continue;
1922 
1923 		if ((d->state == BT_CONNECTED || d->state == BT_DISCONN) &&
1924 						d->mscex == RFCOMM_MSCEX_OK)
1925 			rfcomm_process_tx(d);
1926 	}
1927 }
1928 
1929 static struct rfcomm_session *rfcomm_process_rx(struct rfcomm_session *s)
1930 {
1931 	struct socket *sock = s->sock;
1932 	struct sock *sk = sock->sk;
1933 	struct sk_buff *skb;
1934 
1935 	BT_DBG("session %p state %ld qlen %d", s, s->state, skb_queue_len(&sk->sk_receive_queue));
1936 
1937 	/* Get data directly from socket receive queue without copying it. */
1938 	while ((skb = skb_dequeue(&sk->sk_receive_queue))) {
1939 		skb_orphan(skb);
1940 		if (!skb_linearize(skb)) {
1941 			s = rfcomm_recv_frame(s, skb);
1942 			if (!s)
1943 				break;
1944 		} else {
1945 			kfree_skb(skb);
1946 		}
1947 	}
1948 
1949 	if (s && (sk->sk_state == BT_CLOSED))
1950 		s = rfcomm_session_close(s, sk->sk_err);
1951 
1952 	return s;
1953 }
1954 
1955 static void rfcomm_accept_connection(struct rfcomm_session *s)
1956 {
1957 	struct socket *sock = s->sock, *nsock;
1958 	int err;
1959 
1960 	/* Fast check for a new connection.
1961 	 * Avoids unnesesary socket allocations. */
1962 	if (list_empty(&bt_sk(sock->sk)->accept_q))
1963 		return;
1964 
1965 	BT_DBG("session %p", s);
1966 
1967 	err = kernel_accept(sock, &nsock, O_NONBLOCK);
1968 	if (err < 0)
1969 		return;
1970 
1971 	/* Set our callbacks */
1972 	nsock->sk->sk_data_ready   = rfcomm_l2data_ready;
1973 	nsock->sk->sk_state_change = rfcomm_l2state_change;
1974 
1975 	s = rfcomm_session_add(nsock, BT_OPEN);
1976 	if (s) {
1977 		/* We should adjust MTU on incoming sessions.
1978 		 * L2CAP MTU minus UIH header and FCS. */
1979 		s->mtu = min(l2cap_pi(nsock->sk)->chan->omtu,
1980 				l2cap_pi(nsock->sk)->chan->imtu) - 5;
1981 
1982 		rfcomm_schedule();
1983 	} else
1984 		sock_release(nsock);
1985 }
1986 
1987 static struct rfcomm_session *rfcomm_check_connection(struct rfcomm_session *s)
1988 {
1989 	struct sock *sk = s->sock->sk;
1990 
1991 	BT_DBG("%p state %ld", s, s->state);
1992 
1993 	switch (sk->sk_state) {
1994 	case BT_CONNECTED:
1995 		s->state = BT_CONNECT;
1996 
1997 		/* We can adjust MTU on outgoing sessions.
1998 		 * L2CAP MTU minus UIH header and FCS. */
1999 		s->mtu = min(l2cap_pi(sk)->chan->omtu, l2cap_pi(sk)->chan->imtu) - 5;
2000 
2001 		rfcomm_send_sabm(s, 0);
2002 		break;
2003 
2004 	case BT_CLOSED:
2005 		s = rfcomm_session_close(s, sk->sk_err);
2006 		break;
2007 	}
2008 	return s;
2009 }
2010 
2011 static void rfcomm_process_sessions(void)
2012 {
2013 	struct rfcomm_session *s, *n;
2014 
2015 	rfcomm_lock();
2016 
2017 	list_for_each_entry_safe(s, n, &session_list, list) {
2018 		if (test_and_clear_bit(RFCOMM_TIMED_OUT, &s->flags)) {
2019 			s->state = BT_DISCONN;
2020 			rfcomm_send_disc(s, 0);
2021 			continue;
2022 		}
2023 
2024 		switch (s->state) {
2025 		case BT_LISTEN:
2026 			rfcomm_accept_connection(s);
2027 			continue;
2028 
2029 		case BT_BOUND:
2030 			s = rfcomm_check_connection(s);
2031 			break;
2032 
2033 		default:
2034 			s = rfcomm_process_rx(s);
2035 			break;
2036 		}
2037 
2038 		if (s)
2039 			rfcomm_process_dlcs(s);
2040 	}
2041 
2042 	rfcomm_unlock();
2043 }
2044 
2045 static int rfcomm_add_listener(bdaddr_t *ba)
2046 {
2047 	struct sockaddr_l2 addr;
2048 	struct socket *sock;
2049 	struct sock *sk;
2050 	struct rfcomm_session *s;
2051 	int    err = 0;
2052 
2053 	/* Create socket */
2054 	err = rfcomm_l2sock_create(&sock);
2055 	if (err < 0) {
2056 		BT_ERR("Create socket failed %d", err);
2057 		return err;
2058 	}
2059 
2060 	/* Bind socket */
2061 	bacpy(&addr.l2_bdaddr, ba);
2062 	addr.l2_family = AF_BLUETOOTH;
2063 	addr.l2_psm    = cpu_to_le16(L2CAP_PSM_RFCOMM);
2064 	addr.l2_cid    = 0;
2065 	addr.l2_bdaddr_type = BDADDR_BREDR;
2066 	err = kernel_bind(sock, (struct sockaddr *) &addr, sizeof(addr));
2067 	if (err < 0) {
2068 		BT_ERR("Bind failed %d", err);
2069 		goto failed;
2070 	}
2071 
2072 	/* Set L2CAP options */
2073 	sk = sock->sk;
2074 	lock_sock(sk);
2075 	/* Set MTU to 0 so L2CAP can auto select the MTU */
2076 	l2cap_pi(sk)->chan->imtu = 0;
2077 	release_sock(sk);
2078 
2079 	/* Start listening on the socket */
2080 	err = kernel_listen(sock, 10);
2081 	if (err) {
2082 		BT_ERR("Listen failed %d", err);
2083 		goto failed;
2084 	}
2085 
2086 	/* Add listening session */
2087 	s = rfcomm_session_add(sock, BT_LISTEN);
2088 	if (!s) {
2089 		err = -ENOMEM;
2090 		goto failed;
2091 	}
2092 
2093 	return 0;
2094 failed:
2095 	sock_release(sock);
2096 	return err;
2097 }
2098 
2099 static void rfcomm_kill_listener(void)
2100 {
2101 	struct rfcomm_session *s, *n;
2102 
2103 	BT_DBG("");
2104 
2105 	list_for_each_entry_safe(s, n, &session_list, list)
2106 		rfcomm_session_del(s);
2107 }
2108 
2109 static int rfcomm_run(void *unused)
2110 {
2111 	DEFINE_WAIT_FUNC(wait, woken_wake_function);
2112 	BT_DBG("");
2113 
2114 	set_user_nice(current, -10);
2115 
2116 	rfcomm_add_listener(BDADDR_ANY);
2117 
2118 	add_wait_queue(&rfcomm_wq, &wait);
2119 	while (!kthread_should_stop()) {
2120 
2121 		/* Process stuff */
2122 		rfcomm_process_sessions();
2123 
2124 		wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
2125 	}
2126 	remove_wait_queue(&rfcomm_wq, &wait);
2127 
2128 	rfcomm_kill_listener();
2129 
2130 	return 0;
2131 }
2132 
2133 static void rfcomm_security_cfm(struct hci_conn *conn, u8 status, u8 encrypt)
2134 {
2135 	struct rfcomm_session *s;
2136 	struct rfcomm_dlc *d, *n;
2137 
2138 	BT_DBG("conn %p status 0x%02x encrypt 0x%02x", conn, status, encrypt);
2139 
2140 	s = rfcomm_session_get(&conn->hdev->bdaddr, &conn->dst);
2141 	if (!s)
2142 		return;
2143 
2144 	list_for_each_entry_safe(d, n, &s->dlcs, list) {
2145 		if (test_and_clear_bit(RFCOMM_SEC_PENDING, &d->flags)) {
2146 			rfcomm_dlc_clear_timer(d);
2147 			if (status || encrypt == 0x00) {
2148 				set_bit(RFCOMM_ENC_DROP, &d->flags);
2149 				continue;
2150 			}
2151 		}
2152 
2153 		if (d->state == BT_CONNECTED && !status && encrypt == 0x00) {
2154 			if (d->sec_level == BT_SECURITY_MEDIUM) {
2155 				set_bit(RFCOMM_SEC_PENDING, &d->flags);
2156 				rfcomm_dlc_set_timer(d, RFCOMM_AUTH_TIMEOUT);
2157 				continue;
2158 			} else if (d->sec_level == BT_SECURITY_HIGH ||
2159 				   d->sec_level == BT_SECURITY_FIPS) {
2160 				set_bit(RFCOMM_ENC_DROP, &d->flags);
2161 				continue;
2162 			}
2163 		}
2164 
2165 		if (!test_and_clear_bit(RFCOMM_AUTH_PENDING, &d->flags))
2166 			continue;
2167 
2168 		if (!status && hci_conn_check_secure(conn, d->sec_level))
2169 			set_bit(RFCOMM_AUTH_ACCEPT, &d->flags);
2170 		else
2171 			set_bit(RFCOMM_AUTH_REJECT, &d->flags);
2172 	}
2173 
2174 	rfcomm_schedule();
2175 }
2176 
2177 static struct hci_cb rfcomm_cb = {
2178 	.name		= "RFCOMM",
2179 	.security_cfm	= rfcomm_security_cfm
2180 };
2181 
2182 static int rfcomm_dlc_debugfs_show(struct seq_file *f, void *x)
2183 {
2184 	struct rfcomm_session *s;
2185 
2186 	rfcomm_lock();
2187 
2188 	list_for_each_entry(s, &session_list, list) {
2189 		struct l2cap_chan *chan = l2cap_pi(s->sock->sk)->chan;
2190 		struct rfcomm_dlc *d;
2191 		list_for_each_entry(d, &s->dlcs, list) {
2192 			seq_printf(f, "%pMR %pMR %ld %d %d %d %d\n",
2193 				   &chan->src, &chan->dst,
2194 				   d->state, d->dlci, d->mtu,
2195 				   d->rx_credits, d->tx_credits);
2196 		}
2197 	}
2198 
2199 	rfcomm_unlock();
2200 
2201 	return 0;
2202 }
2203 
2204 DEFINE_SHOW_ATTRIBUTE(rfcomm_dlc_debugfs);
2205 
2206 static struct dentry *rfcomm_dlc_debugfs;
2207 
2208 /* ---- Initialization ---- */
2209 static int __init rfcomm_init(void)
2210 {
2211 	int err;
2212 
2213 	hci_register_cb(&rfcomm_cb);
2214 
2215 	rfcomm_thread = kthread_run(rfcomm_run, NULL, "krfcommd");
2216 	if (IS_ERR(rfcomm_thread)) {
2217 		err = PTR_ERR(rfcomm_thread);
2218 		goto unregister;
2219 	}
2220 
2221 	err = rfcomm_init_ttys();
2222 	if (err < 0)
2223 		goto stop;
2224 
2225 	err = rfcomm_init_sockets();
2226 	if (err < 0)
2227 		goto cleanup;
2228 
2229 	BT_INFO("RFCOMM ver %s", VERSION);
2230 
2231 	if (IS_ERR_OR_NULL(bt_debugfs))
2232 		return 0;
2233 
2234 	rfcomm_dlc_debugfs = debugfs_create_file("rfcomm_dlc", 0444,
2235 						 bt_debugfs, NULL,
2236 						 &rfcomm_dlc_debugfs_fops);
2237 
2238 	return 0;
2239 
2240 cleanup:
2241 	rfcomm_cleanup_ttys();
2242 
2243 stop:
2244 	kthread_stop(rfcomm_thread);
2245 
2246 unregister:
2247 	hci_unregister_cb(&rfcomm_cb);
2248 
2249 	return err;
2250 }
2251 
2252 static void __exit rfcomm_exit(void)
2253 {
2254 	debugfs_remove(rfcomm_dlc_debugfs);
2255 
2256 	hci_unregister_cb(&rfcomm_cb);
2257 
2258 	kthread_stop(rfcomm_thread);
2259 
2260 	rfcomm_cleanup_ttys();
2261 
2262 	rfcomm_cleanup_sockets();
2263 }
2264 
2265 module_init(rfcomm_init);
2266 module_exit(rfcomm_exit);
2267 
2268 module_param(disable_cfc, bool, 0644);
2269 MODULE_PARM_DESC(disable_cfc, "Disable credit based flow control");
2270 
2271 module_param(channel_mtu, int, 0644);
2272 MODULE_PARM_DESC(channel_mtu, "Default MTU for the RFCOMM channel");
2273 
2274 module_param(l2cap_ertm, bool, 0644);
2275 MODULE_PARM_DESC(l2cap_ertm, "Use L2CAP ERTM mode for connection");
2276 
2277 MODULE_AUTHOR("Marcel Holtmann <marcel@holtmann.org>");
2278 MODULE_DESCRIPTION("Bluetooth RFCOMM ver " VERSION);
2279 MODULE_VERSION(VERSION);
2280 MODULE_LICENSE("GPL");
2281 MODULE_ALIAS("bt-proto-3");
2282