xref: /dragonfly/sys/netbt/rfcomm_session.c (revision 3641b7ca)
1 /* $DragonFly: src/sys/netbt/rfcomm_session.c,v 1.2 2008/03/18 13:41:42 hasso Exp $ */
2 /* $OpenBSD: src/sys/netbt/rfcomm_session.c,v 1.3 2008/02/24 21:34:48 uwe Exp $ */
3 /* $NetBSD: rfcomm_session.c,v 1.12 2008/01/31 19:30:23 plunky Exp $ */
4 
5 /*-
6  * Copyright (c) 2006 Itronix Inc.
7  * All rights reserved.
8  *
9  * Written by Iain Hibbert for Itronix Inc.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 3. The name of Itronix Inc. may not be used to endorse
20  *    or promote products derived from this software without specific
21  *    prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY ITRONIX INC. ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
25  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
26  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL ITRONIX INC. BE LIABLE FOR ANY
27  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
28  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
29  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
30  * ON ANY THEORY OF LIABILITY, WHETHER IN
31  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
32  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
33  * POSSIBILITY OF SUCH DAMAGE.
34  */
35 
36 #include <sys/param.h>
37 #include <sys/kernel.h>
38 #include <sys/mbuf.h>
39 #include <sys/proc.h>
40 #include <sys/systm.h>
41 #include <sys/types.h>
42 #include <sys/endian.h>
43 
44 #include <net/if.h>
45 #include <net/pf/pfvar.h>
46 
47 #include <netbt/bluetooth.h>
48 #include <netbt/hci.h>
49 #include <netbt/l2cap.h>
50 #include <netbt/rfcomm.h>
51 
52 /******************************************************************************
53  *
54  * RFCOMM Multiplexer Sessions sit directly on L2CAP channels, and can
55  * multiplex up to 30 incoming and 30 outgoing connections.
56  * Only one Multiplexer is allowed between any two devices.
57  */
58 
59 static void rfcomm_session_recv_sabm(struct rfcomm_session *, int);
60 static void rfcomm_session_recv_disc(struct rfcomm_session *, int);
61 static void rfcomm_session_recv_ua(struct rfcomm_session *, int);
62 static void rfcomm_session_recv_dm(struct rfcomm_session *, int);
63 static void rfcomm_session_recv_uih(struct rfcomm_session *, int, int, struct mbuf *, int);
64 static void rfcomm_session_recv_mcc(struct rfcomm_session *, struct mbuf *);
65 static void rfcomm_session_recv_mcc_test(struct rfcomm_session *, int, struct mbuf *);
66 static void rfcomm_session_recv_mcc_fcon(struct rfcomm_session *, int);
67 static void rfcomm_session_recv_mcc_fcoff(struct rfcomm_session *, int);
68 static void rfcomm_session_recv_mcc_msc(struct rfcomm_session *, int, struct mbuf *);
69 static void rfcomm_session_recv_mcc_rpn(struct rfcomm_session *, int, struct mbuf *);
70 static void rfcomm_session_recv_mcc_rls(struct rfcomm_session *, int, struct mbuf *);
71 static void rfcomm_session_recv_mcc_pn(struct rfcomm_session *, int, struct mbuf *);
72 static void rfcomm_session_recv_mcc_nsc(struct rfcomm_session *, int, struct mbuf *);
73 
74 /* L2CAP callbacks */
75 static void rfcomm_session_connecting(void *);
76 static void rfcomm_session_connected(void *);
77 static void rfcomm_session_disconnected(void *, int);
78 static void *rfcomm_session_newconn(void *, struct sockaddr_bt *, struct sockaddr_bt *);
79 static void rfcomm_session_complete(void *, int);
80 static void rfcomm_session_linkmode(void *, int);
81 static void rfcomm_session_input(void *, struct mbuf *);
82 
83 static const struct btproto rfcomm_session_proto = {
84 	rfcomm_session_connecting,
85 	rfcomm_session_connected,
86 	rfcomm_session_disconnected,
87 	rfcomm_session_newconn,
88 	rfcomm_session_complete,
89 	rfcomm_session_linkmode,
90 	rfcomm_session_input,
91 };
92 
93 struct rfcomm_session_list
94 	rfcomm_session_active = LIST_HEAD_INITIALIZER(rfcomm_session_active);
95 
96 struct rfcomm_session_list
97 	rfcomm_session_listen = LIST_HEAD_INITIALIZER(rfcomm_session_listen);
98 
99 vm_zone_t rfcomm_credit_pool;
100 
101 /*
102  * RFCOMM System Parameters (see section 5.3)
103  */
104 int rfcomm_mtu_default = 127;	/* bytes */
105 int rfcomm_ack_timeout = 20;	/* seconds */
106 int rfcomm_mcc_timeout = 20;	/* seconds */
107 
108 /*
109  * Reversed CRC table as per TS 07.10 Annex B.3.5
110  */
111 static const uint8_t crctable[256] = {	/* reversed, 8-bit, poly=0x07 */
112 	0x00, 0x91, 0xe3, 0x72, 0x07, 0x96, 0xe4, 0x75,
113 	0x0e, 0x9f, 0xed, 0x7c, 0x09, 0x98, 0xea, 0x7b,
114 	0x1c, 0x8d, 0xff, 0x6e, 0x1b, 0x8a, 0xf8, 0x69,
115 	0x12, 0x83, 0xf1, 0x60, 0x15, 0x84, 0xf6, 0x67,
116 
117 	0x38, 0xa9, 0xdb, 0x4a, 0x3f, 0xae, 0xdc, 0x4d,
118 	0x36, 0xa7, 0xd5, 0x44, 0x31, 0xa0, 0xd2, 0x43,
119 	0x24, 0xb5, 0xc7, 0x56, 0x23, 0xb2, 0xc0, 0x51,
120 	0x2a, 0xbb, 0xc9, 0x58, 0x2d, 0xbc, 0xce, 0x5f,
121 
122 	0x70, 0xe1, 0x93, 0x02, 0x77, 0xe6, 0x94, 0x05,
123 	0x7e, 0xef, 0x9d, 0x0c, 0x79, 0xe8, 0x9a, 0x0b,
124 	0x6c, 0xfd, 0x8f, 0x1e, 0x6b, 0xfa, 0x88, 0x19,
125 	0x62, 0xf3, 0x81, 0x10, 0x65, 0xf4, 0x86, 0x17,
126 
127 	0x48, 0xd9, 0xab, 0x3a, 0x4f, 0xde, 0xac, 0x3d,
128 	0x46, 0xd7, 0xa5, 0x34, 0x41, 0xd0, 0xa2, 0x33,
129 	0x54, 0xc5, 0xb7, 0x26, 0x53, 0xc2, 0xb0, 0x21,
130 	0x5a, 0xcb, 0xb9, 0x28, 0x5d, 0xcc, 0xbe, 0x2f,
131 
132 	0xe0, 0x71, 0x03, 0x92, 0xe7, 0x76, 0x04, 0x95,
133 	0xee, 0x7f, 0x0d, 0x9c, 0xe9, 0x78, 0x0a, 0x9b,
134 	0xfc, 0x6d, 0x1f, 0x8e, 0xfb, 0x6a, 0x18, 0x89,
135 	0xf2, 0x63, 0x11, 0x80, 0xf5, 0x64, 0x16, 0x87,
136 
137 	0xd8, 0x49, 0x3b, 0xaa, 0xdf, 0x4e, 0x3c, 0xad,
138 	0xd6, 0x47, 0x35, 0xa4, 0xd1, 0x40, 0x32, 0xa3,
139 	0xc4, 0x55, 0x27, 0xb6, 0xc3, 0x52, 0x20, 0xb1,
140 	0xca, 0x5b, 0x29, 0xb8, 0xcd, 0x5c, 0x2e, 0xbf,
141 
142 	0x90, 0x01, 0x73, 0xe2, 0x97, 0x06, 0x74, 0xe5,
143 	0x9e, 0x0f, 0x7d, 0xec, 0x99, 0x08, 0x7a, 0xeb,
144 	0x8c, 0x1d, 0x6f, 0xfe, 0x8b, 0x1a, 0x68, 0xf9,
145 	0x82, 0x13, 0x61, 0xf0, 0x85, 0x14, 0x66, 0xf7,
146 
147 	0xa8, 0x39, 0x4b, 0xda, 0xaf, 0x3e, 0x4c, 0xdd,
148 	0xa6, 0x37, 0x45, 0xd4, 0xa1, 0x30, 0x42, 0xd3,
149 	0xb4, 0x25, 0x57, 0xc6, 0xb3, 0x22, 0x50, 0xc1,
150 	0xba, 0x2b, 0x59, 0xc8, 0xbd, 0x2c, 0x5e, 0xcf
151 };
152 
153 #define FCS(f, d)	crctable[(f) ^ (d)]
154 
155 /*
156  * rfcomm_init()
157  *
158  * initialize the "credit pool".
159  */
160 void
161 rfcomm_init(void)
162 {
163 	rfcomm_credit_pool = zinit("rfcomm_credit",
164 	    sizeof(struct rfcomm_credit), 0, 0, 0);
165 }
166 
167 /*
168  * rfcomm_session_alloc(list, sockaddr)
169  *
170  * allocate a new session and fill in the blanks, then
171  * attach session to front of specified list (active or listen)
172  */
173 struct rfcomm_session *
174 rfcomm_session_alloc(struct rfcomm_session_list *list,
175 			struct sockaddr_bt *laddr)
176 {
177 	struct rfcomm_session *rs;
178 	int err;
179 
180 	rs = kmalloc(sizeof(*rs), M_BLUETOOTH, M_NOWAIT | M_ZERO);
181 	if (rs == NULL)
182 		return NULL;
183 
184 	rs->rs_state = RFCOMM_SESSION_CLOSED;
185 
186 	callout_init(&rs->rs_timeout);
187 
188 	STAILQ_INIT(&rs->rs_credits);
189 	LIST_INIT(&rs->rs_dlcs);
190 
191 	err = l2cap_attach(&rs->rs_l2cap, &rfcomm_session_proto, rs);
192 	if (err) {
193 		kfree(rs, M_BLUETOOTH);
194 		return NULL;
195 	}
196 
197 	(void)l2cap_getopt(rs->rs_l2cap, SO_L2CAP_OMTU, &rs->rs_mtu);
198 
199 	if (laddr->bt_psm == L2CAP_PSM_ANY)
200 		laddr->bt_psm = L2CAP_PSM_RFCOMM;
201 
202 	(void)l2cap_bind(rs->rs_l2cap, laddr);
203 
204 	LIST_INSERT_HEAD(list, rs, rs_next);
205 
206 	return rs;
207 }
208 
209 /*
210  * rfcomm_session_free(rfcomm_session)
211  *
212  * release a session, including any cleanup
213  */
214 void
215 rfcomm_session_free(struct rfcomm_session *rs)
216 {
217 	struct rfcomm_credit *credit;
218 
219 	KKASSERT(rs != NULL);
220 	KKASSERT(LIST_EMPTY(&rs->rs_dlcs));
221 
222 	rs->rs_state = RFCOMM_SESSION_CLOSED;
223 
224 	/*
225 	 * If the callout is already invoked we have no way to stop it,
226 	 * but it will call us back right away (there are no DLC's) so
227 	 * not to worry.
228 	 */
229 	callout_stop(&rs->rs_timeout);
230 	if (callout_active(&rs->rs_timeout))
231 		return;
232 
233 	/*
234 	 * Take care that rfcomm_session_disconnected() doesnt call
235 	 * us back either as it will do if the l2cap_channel has not
236 	 * been closed when we detach it..
237 	 */
238 	if (rs->rs_flags & RFCOMM_SESSION_FREE)
239 		return;
240 
241 	rs->rs_flags |= RFCOMM_SESSION_FREE;
242 
243 	/* throw away any remaining credit notes */
244 	while ((credit = STAILQ_FIRST(&rs->rs_credits)) != NULL) {
245 		STAILQ_REMOVE_HEAD(&rs->rs_credits, rc_next);
246 		pool_put(&rfcomm_credit_pool, credit);
247 	}
248 
249 	KKASSERT(STAILQ_EMPTY(&rs->rs_credits));
250 
251 	/* Goodbye! */
252 	LIST_REMOVE(rs, rs_next);
253 	l2cap_detach(&rs->rs_l2cap);
254 	kfree(rs, M_BLUETOOTH);
255 }
256 
257 /*
258  * rfcomm_session_lookup(sockaddr, sockaddr)
259  *
260  * Find active rfcomm session matching src and dest addresses
261  * when src is BDADDR_ANY match any local address
262  */
263 struct rfcomm_session *
264 rfcomm_session_lookup(struct sockaddr_bt *src, struct sockaddr_bt *dest)
265 {
266 	struct rfcomm_session *rs;
267 	struct sockaddr_bt addr;
268 
269 	LIST_FOREACH(rs, &rfcomm_session_active, rs_next) {
270 		if (rs->rs_state == RFCOMM_SESSION_CLOSED)
271 			continue;
272 
273 		l2cap_sockaddr(rs->rs_l2cap, &addr);
274 
275 		if (bdaddr_same(&src->bt_bdaddr, &addr.bt_bdaddr) == 0)
276 			if (bdaddr_any(&src->bt_bdaddr) == 0)
277 				continue;
278 
279 		l2cap_peeraddr(rs->rs_l2cap, &addr);
280 
281 		if (addr.bt_psm != dest->bt_psm)
282 			continue;
283 
284 		if (bdaddr_same(&dest->bt_bdaddr, &addr.bt_bdaddr))
285 			break;
286 	}
287 
288 	return rs;
289 }
290 
291 /*
292  * rfcomm_session_timeout(rfcomm_session)
293  *
294  * Session timeouts are scheduled when a session is left or
295  * created with no DLCs, and when SABM(0) or DISC(0) are
296  * sent.
297  *
298  * So, if it is in an open state with DLC's attached then
299  * we leave it alone, otherwise the session is lost.
300  */
301 void
302 rfcomm_session_timeout(void *arg)
303 {
304 	struct rfcomm_session *rs = arg;
305 	struct rfcomm_dlc *dlc;
306 
307 	KKASSERT(rs != NULL);
308 
309 	crit_enter();
310 
311 	if (rs->rs_state != RFCOMM_SESSION_OPEN) {
312 		DPRINTF("timeout\n");
313 		rs->rs_state = RFCOMM_SESSION_CLOSED;
314 
315 		while (!LIST_EMPTY(&rs->rs_dlcs)) {
316 			dlc = LIST_FIRST(&rs->rs_dlcs);
317 
318 			rfcomm_dlc_close(dlc, ETIMEDOUT);
319 		}
320 	}
321 
322 	if (LIST_EMPTY(&rs->rs_dlcs)) {
323 		DPRINTF("expiring\n");
324 		rfcomm_session_free(rs);
325 	}
326 	crit_exit();
327 }
328 
329 /***********************************************************************
330  *
331  *	RFCOMM Session L2CAP protocol callbacks
332  *
333  */
334 
335 static void
336 rfcomm_session_connecting(void *arg)
337 {
338 	/* struct rfcomm_session *rs = arg; */
339 
340 	DPRINTF("Connecting\n");
341 }
342 
343 static void
344 rfcomm_session_connected(void *arg)
345 {
346 	struct rfcomm_session *rs = arg;
347 
348 	DPRINTF("Connected\n");
349 
350 	/*
351 	 * L2CAP is open.
352 	 *
353 	 * If we are initiator, we can send our SABM(0)
354 	 * a timeout should be active?
355 	 *
356 	 * We must take note of the L2CAP MTU because currently
357 	 * the L2CAP implementation can only do Basic Mode.
358 	 */
359 	l2cap_getopt(rs->rs_l2cap, SO_L2CAP_OMTU, &rs->rs_mtu);
360 
361 	rs->rs_mtu -= 6; /* (RFCOMM overhead could be this big) */
362 	if (rs->rs_mtu < RFCOMM_MTU_MIN) {
363 		rfcomm_session_disconnected(rs, EINVAL);
364 		return;
365 	}
366 
367 	if (IS_INITIATOR(rs)) {
368 		int err;
369 
370 		err = rfcomm_session_send_frame(rs, RFCOMM_FRAME_SABM, 0);
371 		if (err)
372 			rfcomm_session_disconnected(rs, err);
373 
374 		callout_reset(&rs->rs_timeout, rfcomm_ack_timeout * hz,
375 		    rfcomm_session_timeout, rs);
376 	}
377 }
378 
379 static void
380 rfcomm_session_disconnected(void *arg, int err)
381 {
382 	struct rfcomm_session *rs = arg;
383 	struct rfcomm_dlc *dlc;
384 
385 	DPRINTF("Disconnected\n");
386 
387 	rs->rs_state = RFCOMM_SESSION_CLOSED;
388 
389 	while (!LIST_EMPTY(&rs->rs_dlcs)) {
390 		dlc = LIST_FIRST(&rs->rs_dlcs);
391 
392 		rfcomm_dlc_close(dlc, err);
393 	}
394 
395 	rfcomm_session_free(rs);
396 }
397 
398 static void *
399 rfcomm_session_newconn(void *arg, struct sockaddr_bt *laddr,
400 				struct sockaddr_bt *raddr)
401 {
402 	struct rfcomm_session *new, *rs = arg;
403 
404 	DPRINTF("New Connection\n");
405 
406 	/*
407 	 * Incoming session connect request. We should return a new
408 	 * session pointer if this is acceptable. The L2CAP layer
409 	 * passes local and remote addresses, which we must check as
410 	 * only one RFCOMM session is allowed between any two devices
411 	 */
412 	new = rfcomm_session_lookup(laddr, raddr);
413 	if (new != NULL)
414 		return NULL;
415 
416 	new = rfcomm_session_alloc(&rfcomm_session_active, laddr);
417 	if (new == NULL)
418 		return NULL;
419 
420 	new->rs_mtu = rs->rs_mtu;
421 	new->rs_state = RFCOMM_SESSION_WAIT_CONNECT;
422 
423 	/*
424 	 * schedule an expiry so that if nothing comes of it we
425 	 * can punt.
426 	 */
427 	callout_reset(&rs->rs_timeout, rfcomm_mcc_timeout * hz,
428 	    rfcomm_session_timeout, rs);
429 
430 	return new->rs_l2cap;
431 }
432 
433 static void
434 rfcomm_session_complete(void *arg, int count)
435 {
436 	struct rfcomm_session *rs = arg;
437 	struct rfcomm_credit *credit;
438 	struct rfcomm_dlc *dlc;
439 
440 	/*
441 	 * count L2CAP packets are 'complete', meaning that they are cleared
442 	 * our buffers (for best effort) or arrived safe (for guaranteed) so
443 	 * we can take it off our list and pass the message on, so that
444 	 * eventually the data can be removed from the sockbuf
445 	 */
446 	while (count-- > 0) {
447 		credit = STAILQ_FIRST(&rs->rs_credits);
448 #ifdef DIAGNOSTIC
449 		if (credit == NULL) {
450 			kprintf("%s: too many packets completed!\n", __func__);
451 			break;
452 		}
453 #endif
454 		dlc = credit->rc_dlc;
455 		if (dlc != NULL) {
456 			dlc->rd_pending--;
457 			(*dlc->rd_proto->complete)
458 					(dlc->rd_upper, credit->rc_len);
459 
460 			/*
461 			 * if not using credit flow control, we may push
462 			 * more data now
463 			 */
464 			if ((rs->rs_flags & RFCOMM_SESSION_CFC) == 0
465 			    && dlc->rd_state == RFCOMM_DLC_OPEN) {
466 				rfcomm_dlc_start(dlc);
467 			}
468 
469 			/*
470 			 * When shutdown is indicated, we are just waiting to
471 			 * clear outgoing data.
472 			 */
473 			if ((dlc->rd_flags & RFCOMM_DLC_SHUTDOWN)
474 			    && dlc->rd_txbuf == NULL && dlc->rd_pending == 0) {
475 				dlc->rd_state = RFCOMM_DLC_WAIT_DISCONNECT;
476 				rfcomm_session_send_frame(rs, RFCOMM_FRAME_DISC,
477 							    dlc->rd_dlci);
478 				callout_reset(&dlc->rd_timeout,
479 				    rfcomm_ack_timeout * hz,
480 				    rfcomm_dlc_timeout, dlc);
481 			}
482 		}
483 
484 		STAILQ_REMOVE_HEAD(&rs->rs_credits, rc_next);
485 		pool_put(&rfcomm_credit_pool, credit);
486 	}
487 
488 	/*
489 	 * If session is closed, we are just waiting to clear the queue
490 	 */
491 	if (rs->rs_state == RFCOMM_SESSION_CLOSED) {
492 		if (STAILQ_EMPTY(&rs->rs_credits))
493 			l2cap_disconnect(rs->rs_l2cap, 0);
494 	}
495 }
496 
497 /*
498  * Link Mode changed
499  *
500  * This is called when a mode change is complete. Proceed with connections
501  * where appropriate, or pass the new mode to any active DLCs.
502  */
503 static void
504 rfcomm_session_linkmode(void *arg, int new)
505 {
506 	struct rfcomm_session *rs = arg;
507 	struct rfcomm_dlc *dlc, *next;
508 	int err, mode = 0;
509 
510 	DPRINTF("auth %s, encrypt %s, secure %s\n",
511 		(new & L2CAP_LM_AUTH ? "on" : "off"),
512 		(new & L2CAP_LM_ENCRYPT ? "on" : "off"),
513 		(new & L2CAP_LM_SECURE ? "on" : "off"));
514 
515 	if (new & L2CAP_LM_AUTH)
516 		mode |= RFCOMM_LM_AUTH;
517 
518 	if (new & L2CAP_LM_ENCRYPT)
519 		mode |= RFCOMM_LM_ENCRYPT;
520 
521 	if (new & L2CAP_LM_SECURE)
522 		mode |= RFCOMM_LM_SECURE;
523 
524 	next = LIST_FIRST(&rs->rs_dlcs);
525 	while ((dlc = next) != NULL) {
526 		next = LIST_NEXT(dlc, rd_next);
527 
528 		switch (dlc->rd_state) {
529 		case RFCOMM_DLC_WAIT_SEND_SABM:	/* we are connecting */
530 			if ((mode & dlc->rd_mode) != dlc->rd_mode) {
531 				rfcomm_dlc_close(dlc, ECONNABORTED);
532 			} else {
533 				err = rfcomm_session_send_frame(rs,
534 					    RFCOMM_FRAME_SABM, dlc->rd_dlci);
535 				if (err) {
536 					rfcomm_dlc_close(dlc, err);
537 				} else {
538 					dlc->rd_state = RFCOMM_DLC_WAIT_RECV_UA;
539 					callout_reset(&dlc->rd_timeout,
540 					    rfcomm_ack_timeout * hz,
541 				    	    rfcomm_dlc_timeout, dlc);
542 
543 					break;
544 				}
545 			}
546 
547 			/*
548 			 * If we aborted the connection and there are no more DLCs
549 			 * on the session, it is our responsibility to disconnect.
550 			 */
551 			if (!LIST_EMPTY(&rs->rs_dlcs))
552 				break;
553 
554 			rs->rs_state = RFCOMM_SESSION_WAIT_DISCONNECT;
555 			rfcomm_session_send_frame(rs, RFCOMM_FRAME_DISC, 0);
556 			callout_reset(&rs->rs_timeout, rfcomm_ack_timeout * hz,
557 			    rfcomm_session_timeout, rs);
558 			break;
559 
560 		case RFCOMM_DLC_WAIT_SEND_UA: /* they are connecting */
561 			if ((mode & dlc->rd_mode) != dlc->rd_mode) {
562 				rfcomm_session_send_frame(rs,
563 					    RFCOMM_FRAME_DM, dlc->rd_dlci);
564 				rfcomm_dlc_close(dlc, ECONNABORTED);
565 				break;
566 			}
567 
568 			err = rfcomm_session_send_frame(rs,
569 					    RFCOMM_FRAME_UA, dlc->rd_dlci);
570 			if (err) {
571 				rfcomm_session_send_frame(rs,
572 						RFCOMM_FRAME_DM, dlc->rd_dlci);
573 				rfcomm_dlc_close(dlc, err);
574 				break;
575 			}
576 
577 			err = rfcomm_dlc_open(dlc);
578 			if (err) {
579 				rfcomm_session_send_frame(rs,
580 						RFCOMM_FRAME_DM, dlc->rd_dlci);
581 				rfcomm_dlc_close(dlc, err);
582 				break;
583 			}
584 
585 			break;
586 
587 		case RFCOMM_DLC_WAIT_RECV_UA:
588 		case RFCOMM_DLC_OPEN: /* already established */
589 			(*dlc->rd_proto->linkmode)(dlc->rd_upper, mode);
590 			break;
591 
592 		default:
593 			break;
594 		}
595 	}
596 }
597 
598 /*
599  * Receive data from L2CAP layer for session. There is always exactly one
600  * RFCOMM frame contained in each L2CAP frame.
601  */
602 static void
603 rfcomm_session_input(void *arg, struct mbuf *m)
604 {
605 	struct rfcomm_session *rs = arg;
606 	int dlci, len, type, pf;
607 	uint8_t fcs, b;
608 
609 	KKASSERT(m != NULL);
610 	KKASSERT(rs != NULL);
611 
612 	/*
613 	 * UIH frames: FCS is only calculated on address and control fields
614 	 * For other frames: FCS is calculated on address, control and length
615 	 * Length may extend to two octets
616 	 */
617 	fcs = 0xff;
618 
619 	if (m->m_pkthdr.len < 4) {
620 		DPRINTF("short frame (%d), discarded\n", m->m_pkthdr.len);
621 		goto done;
622 	}
623 
624 	/* address - one octet */
625 	m_copydata(m, 0, 1, &b);
626 	m_adj(m, 1);
627 	fcs = FCS(fcs, b);
628 	dlci = RFCOMM_DLCI(b);
629 
630 	/* control - one octet */
631 	m_copydata(m, 0, 1, &b);
632 	m_adj(m, 1);
633 	fcs = FCS(fcs, b);
634 	type = RFCOMM_TYPE(b);
635 	pf = RFCOMM_PF(b);
636 
637 	/* length - may be two octets */
638 	m_copydata(m, 0, 1, &b);
639 	m_adj(m, 1);
640 	if (type != RFCOMM_FRAME_UIH)
641 		fcs = FCS(fcs, b);
642 	len = (b >> 1) & 0x7f;
643 
644 	if (RFCOMM_EA(b) == 0) {
645 		if (m->m_pkthdr.len < 2) {
646 			DPRINTF("short frame (%d, EA = 0), discarded\n",
647 				m->m_pkthdr.len);
648 			goto done;
649 		}
650 
651 		m_copydata(m, 0, 1, &b);
652 		m_adj(m, 1);
653 		if (type != RFCOMM_FRAME_UIH)
654 			fcs = FCS(fcs, b);
655 
656 		len |= (b << 7);
657 	}
658 
659 	/* FCS byte is last octet in frame */
660 	m_copydata(m, m->m_pkthdr.len - 1, 1, &b);
661 	m_adj(m, -1);
662 	fcs = FCS(fcs, b);
663 
664 	if (fcs != 0xcf) {
665 		DPRINTF("Bad FCS value (%#2.2x), frame discarded\n", fcs);
666 		goto done;
667 	}
668 
669 	DPRINTFN(10, "dlci %d, type %2.2x, len = %d\n", dlci, type, len);
670 
671 	switch (type) {
672 	case RFCOMM_FRAME_SABM:
673 		if (pf)
674 			rfcomm_session_recv_sabm(rs, dlci);
675 		break;
676 
677 	case RFCOMM_FRAME_DISC:
678 		if (pf)
679 			rfcomm_session_recv_disc(rs, dlci);
680 		break;
681 
682 	case RFCOMM_FRAME_UA:
683 		if (pf)
684 			rfcomm_session_recv_ua(rs, dlci);
685 		break;
686 
687 	case RFCOMM_FRAME_DM:
688 		rfcomm_session_recv_dm(rs, dlci);
689 		break;
690 
691 	case RFCOMM_FRAME_UIH:
692 		rfcomm_session_recv_uih(rs, dlci, pf, m, len);
693 		return;	/* (no release) */
694 
695 	default:
696 		UNKNOWN(type);
697 		break;
698 	}
699 
700 done:
701 	m_freem(m);
702 }
703 
704 /***********************************************************************
705  *
706  *	RFCOMM Session receive processing
707  */
708 
709 /*
710  * rfcomm_session_recv_sabm(rfcomm_session, dlci)
711  *
712  * Set Asyncrhonous Balanced Mode - open the channel.
713  */
714 static void
715 rfcomm_session_recv_sabm(struct rfcomm_session *rs, int dlci)
716 {
717 	struct rfcomm_dlc *dlc;
718 	int err;
719 
720 	DPRINTFN(5, "SABM(%d)\n", dlci);
721 
722 	if (dlci == 0) {	/* Open Session */
723 		rs->rs_state = RFCOMM_SESSION_OPEN;
724 		rfcomm_session_send_frame(rs, RFCOMM_FRAME_UA, 0);
725 		LIST_FOREACH(dlc, &rs->rs_dlcs, rd_next) {
726 			if (dlc->rd_state == RFCOMM_DLC_WAIT_SESSION)
727 				rfcomm_dlc_connect(dlc);
728 		}
729 		return;
730 	}
731 
732 	if (rs->rs_state != RFCOMM_SESSION_OPEN) {
733 		DPRINTF("session was not even open!\n");
734 		return;
735 	}
736 
737 	/* validate direction bit */
738 	if ((IS_INITIATOR(rs) && !RFCOMM_DIRECTION(dlci))
739 	    || (!IS_INITIATOR(rs) && RFCOMM_DIRECTION(dlci))) {
740 		DPRINTF("Invalid direction bit on DLCI\n");
741 		return;
742 	}
743 
744 	/*
745 	 * look for our DLC - this may exist if we received PN
746 	 * already, or we may have to fabricate a new one.
747 	 */
748 	dlc = rfcomm_dlc_lookup(rs, dlci);
749 	if (dlc == NULL) {
750 		dlc = rfcomm_dlc_newconn(rs, dlci);
751 		if (dlc == NULL)
752 			return;	/* (DM is sent) */
753 	}
754 
755 	/*
756 	 * ..but if this DLC is not waiting to connect, they did
757 	 * something wrong, ignore it.
758 	 */
759 	if (dlc->rd_state != RFCOMM_DLC_WAIT_CONNECT)
760 		return;
761 
762 	/* set link mode */
763 	err = rfcomm_dlc_setmode(dlc);
764 	if (err == EINPROGRESS) {
765 		dlc->rd_state = RFCOMM_DLC_WAIT_SEND_UA;
766 		(*dlc->rd_proto->connecting)(dlc->rd_upper);
767 		return;
768 	}
769 	if (err)
770 		goto close;
771 
772 	err = rfcomm_session_send_frame(rs, RFCOMM_FRAME_UA, dlci);
773 	if (err)
774 		goto close;
775 
776 	/* and mark it open */
777 	err = rfcomm_dlc_open(dlc);
778 	if (err)
779 		goto close;
780 
781 	return;
782 
783 close:
784 	rfcomm_dlc_close(dlc, err);
785 }
786 
787 /*
788  * Receive Disconnect Command
789  */
790 static void
791 rfcomm_session_recv_disc(struct rfcomm_session *rs, int dlci)
792 {
793 	struct rfcomm_dlc *dlc;
794 
795 	DPRINTFN(5, "DISC(%d)\n", dlci);
796 
797 	if (dlci == 0) {
798 		/*
799 		 * Disconnect Session
800 		 *
801 		 * We set the session state to CLOSED so that when
802 		 * the UA frame is clear the session will be closed
803 		 * automatically. We wont bother to close any DLC's
804 		 * just yet as there should be none. In the unlikely
805 		 * event that something is left, it will get flushed
806 		 * out as the session goes down.
807 		 */
808 		rfcomm_session_send_frame(rs, RFCOMM_FRAME_UA, 0);
809 		rs->rs_state = RFCOMM_SESSION_CLOSED;
810 		return;
811 	}
812 
813 	dlc = rfcomm_dlc_lookup(rs, dlci);
814 	if (dlc == NULL) {
815 		rfcomm_session_send_frame(rs, RFCOMM_FRAME_DM, dlci);
816 		return;
817 	}
818 
819 	rfcomm_dlc_close(dlc, ECONNRESET);
820 	rfcomm_session_send_frame(rs, RFCOMM_FRAME_UA, dlci);
821 }
822 
823 /*
824  * Receive Unnumbered Acknowledgement Response
825  *
826  * This should be a response to a DISC or SABM frame that we
827  * have previously sent. If unexpected, ignore it.
828  */
829 static void
830 rfcomm_session_recv_ua(struct rfcomm_session *rs, int dlci)
831 {
832 	struct rfcomm_dlc *dlc;
833 
834 	DPRINTFN(5, "UA(%d)\n", dlci);
835 
836 	if (dlci == 0) {
837 		switch (rs->rs_state) {
838 		case RFCOMM_SESSION_WAIT_CONNECT:	/* We sent SABM */
839 			callout_stop(&rs->rs_timeout);
840 			rs->rs_state = RFCOMM_SESSION_OPEN;
841 			LIST_FOREACH(dlc, &rs->rs_dlcs, rd_next) {
842 				if (dlc->rd_state == RFCOMM_DLC_WAIT_SESSION)
843 					rfcomm_dlc_connect(dlc);
844 			}
845 			break;
846 
847 		case RFCOMM_SESSION_WAIT_DISCONNECT:	/* We sent DISC */
848 			callout_stop(&rs->rs_timeout);
849 			rs->rs_state = RFCOMM_SESSION_CLOSED;
850 			l2cap_disconnect(rs->rs_l2cap, 0);
851 			break;
852 
853 		default:
854 			DPRINTF("Received spurious UA(0)!\n");
855 			break;
856 		}
857 
858 		return;
859 	}
860 
861 	/*
862 	 * If we have no DLC on this dlci, we may have aborted
863 	 * without shutting down properly, so check if the session
864 	 * needs disconnecting.
865 	 */
866 	dlc = rfcomm_dlc_lookup(rs, dlci);
867 	if (dlc == NULL)
868 		goto check;
869 
870 	switch (dlc->rd_state) {
871 	case RFCOMM_DLC_WAIT_RECV_UA:		/* We sent SABM */
872 		rfcomm_dlc_open(dlc);
873 		return;
874 
875 	case RFCOMM_DLC_WAIT_DISCONNECT:	/* We sent DISC */
876 		rfcomm_dlc_close(dlc, 0);
877 		break;
878 
879 	default:
880 		DPRINTF("Received spurious UA(%d)!\n", dlci);
881 		return;
882 	}
883 
884 check:	/* last one out turns out the light */
885 	if (LIST_EMPTY(&rs->rs_dlcs)) {
886 		rs->rs_state = RFCOMM_SESSION_WAIT_DISCONNECT;
887 		rfcomm_session_send_frame(rs, RFCOMM_FRAME_DISC, 0);
888 		callout_reset(&rs->rs_timeout, rfcomm_ack_timeout*hz,rfcomm_session_timeout,rs);
889 	}
890 }
891 
892 /*
893  * Receive Disconnected Mode Response
894  *
895  * If this does not apply to a known DLC then we may ignore it.
896  */
897 static void
898 rfcomm_session_recv_dm(struct rfcomm_session *rs, int dlci)
899 {
900 	struct rfcomm_dlc *dlc;
901 
902 	DPRINTFN(5, "DM(%d)\n", dlci);
903 
904 	dlc = rfcomm_dlc_lookup(rs, dlci);
905 	if (dlc == NULL)
906 		return;
907 
908 	if (dlc->rd_state == RFCOMM_DLC_WAIT_CONNECT)
909 		rfcomm_dlc_close(dlc, ECONNREFUSED);
910 	else
911 		rfcomm_dlc_close(dlc, ECONNRESET);
912 }
913 
914 /*
915  * Receive Unnumbered Information with Header check (MCC or data packet)
916  */
917 static void
918 rfcomm_session_recv_uih(struct rfcomm_session *rs, int dlci,
919 			int pf, struct mbuf *m, int len)
920 {
921 	struct rfcomm_dlc *dlc;
922 	uint8_t credits = 0;
923 
924 	DPRINTFN(10, "UIH(%d)\n", dlci);
925 
926 	if (dlci == 0) {
927 		rfcomm_session_recv_mcc(rs, m);
928 		return;
929 	}
930 
931 	if (m->m_pkthdr.len != len + pf) {
932 		DPRINTF("Bad Frame Length (%d), frame discarded\n",
933 			    m->m_pkthdr.len);
934 
935 		goto discard;
936 	}
937 
938 	dlc = rfcomm_dlc_lookup(rs, dlci);
939 	if (dlc == NULL) {
940 		DPRINTF("UIH received for non existent DLC, discarded\n");
941 		rfcomm_session_send_frame(rs, RFCOMM_FRAME_DM, dlci);
942 		goto discard;
943 	}
944 
945 	if (dlc->rd_state != RFCOMM_DLC_OPEN) {
946 		DPRINTF("non-open DLC (state = %d), discarded\n",
947 				dlc->rd_state);
948 		goto discard;
949 	}
950 
951 	/* if PF is set, credits were included */
952 	if (rs->rs_flags & RFCOMM_SESSION_CFC) {
953 		if (pf != 0) {
954 			if (m->m_pkthdr.len < sizeof(credits)) {
955 				DPRINTF("Bad PF value, UIH discarded\n");
956 				goto discard;
957 			}
958 
959 			m_copydata(m, 0, sizeof(credits), &credits);
960 			m_adj(m, sizeof(credits));
961 
962 			dlc->rd_txcred += credits;
963 
964 			if (credits > 0 && dlc->rd_txbuf != NULL)
965 				rfcomm_dlc_start(dlc);
966 		}
967 
968 		if (len == 0)
969 			goto discard;
970 
971 		if (dlc->rd_rxcred == 0) {
972 			DPRINTF("Credit limit reached, UIH discarded\n");
973 			goto discard;
974 		}
975 
976 		if (len > dlc->rd_rxsize) {
977 			DPRINTF("UIH frame exceeds rxsize, discarded\n");
978 			goto discard;
979 		}
980 
981 		dlc->rd_rxcred--;
982 		dlc->rd_rxsize -= len;
983 	}
984 
985 	(*dlc->rd_proto->input)(dlc->rd_upper, m);
986 	return;
987 
988 discard:
989 	m_freem(m);
990 }
991 
992 /*
993  * Receive Multiplexer Control Command
994  */
995 static void
996 rfcomm_session_recv_mcc(struct rfcomm_session *rs, struct mbuf *m)
997 {
998 	int type, cr, len;
999 	uint8_t b;
1000 
1001 	/*
1002 	 * Extract MCC header.
1003 	 *
1004 	 * Fields are variable length using extension bit = 1 to signify the
1005 	 * last octet in the sequence.
1006 	 *
1007 	 * Only single octet types are defined in TS 07.10/RFCOMM spec
1008 	 *
1009 	 * Length can realistically only use 15 bits (max RFCOMM MTU)
1010 	 */
1011 	if (m->m_pkthdr.len < sizeof(b)) {
1012 		DPRINTF("Short MCC header, discarded\n");
1013 		goto release;
1014 	}
1015 
1016 	m_copydata(m, 0, sizeof(b), &b);
1017 	m_adj(m, sizeof(b));
1018 
1019 	if (RFCOMM_EA(b) == 0) {	/* verify no extensions */
1020 		DPRINTF("MCC type EA = 0, discarded\n");
1021 		goto release;
1022 	}
1023 
1024 	type = RFCOMM_MCC_TYPE(b);
1025 	cr = RFCOMM_CR(b);
1026 
1027 	len = 0;
1028 	do {
1029 		if (m->m_pkthdr.len < sizeof(b)) {
1030 			DPRINTF("Short MCC header, discarded\n");
1031 			goto release;
1032 		}
1033 
1034 		m_copydata(m, 0, sizeof(b), &b);
1035 		m_adj(m, sizeof(b));
1036 
1037 		len = (len << 7) | (b >> 1);
1038 		len = min(len, RFCOMM_MTU_MAX);
1039 	} while (RFCOMM_EA(b) == 0);
1040 
1041 	if (len != m->m_pkthdr.len) {
1042 		DPRINTF("Incorrect MCC length, discarded\n");
1043 		goto release;
1044 	}
1045 
1046 	DPRINTFN(2, "MCC %s type %2.2x (%d bytes)\n",
1047 		(cr ? "command" : "response"), type, len);
1048 
1049 	/*
1050 	 * pass to command handler
1051 	 */
1052 	switch(type) {
1053 	case RFCOMM_MCC_TEST:	/* Test */
1054 		rfcomm_session_recv_mcc_test(rs, cr, m);
1055 		break;
1056 
1057 	case RFCOMM_MCC_FCON:	/* Flow Control On */
1058 		rfcomm_session_recv_mcc_fcon(rs, cr);
1059 		break;
1060 
1061 	case RFCOMM_MCC_FCOFF:	/* Flow Control Off */
1062 		rfcomm_session_recv_mcc_fcoff(rs, cr);
1063 		break;
1064 
1065 	case RFCOMM_MCC_MSC:	/* Modem Status Command */
1066 		rfcomm_session_recv_mcc_msc(rs, cr, m);
1067 		break;
1068 
1069 	case RFCOMM_MCC_RPN:	/* Remote Port Negotiation */
1070 		rfcomm_session_recv_mcc_rpn(rs, cr, m);
1071 		break;
1072 
1073 	case RFCOMM_MCC_RLS:	/* Remote Line Status */
1074 		rfcomm_session_recv_mcc_rls(rs, cr, m);
1075 		break;
1076 
1077 	case RFCOMM_MCC_PN:	/* Parameter Negotiation */
1078 		rfcomm_session_recv_mcc_pn(rs, cr, m);
1079 		break;
1080 
1081 	case RFCOMM_MCC_NSC:	/* Non Supported Command */
1082 		rfcomm_session_recv_mcc_nsc(rs, cr, m);
1083 		break;
1084 
1085 	default:
1086 		b = RFCOMM_MKMCC_TYPE(cr, type);
1087 		rfcomm_session_send_mcc(rs, 0, RFCOMM_MCC_NSC, &b, sizeof(b));
1088 	}
1089 
1090 release:
1091 	m_freem(m);
1092 }
1093 
1094 /*
1095  * process TEST command/response
1096  */
1097 static void
1098 rfcomm_session_recv_mcc_test(struct rfcomm_session *rs, int cr, struct mbuf *m)
1099 {
1100 	void *data;
1101 	int len;
1102 
1103 	if (cr == 0)	/* ignore ack */
1104 		return;
1105 
1106 	/*
1107 	 * we must send all the data they included back as is
1108 	 */
1109 
1110 	len = m->m_pkthdr.len;
1111 	if (len > RFCOMM_MTU_MAX)
1112 		return;
1113 
1114 	data = kmalloc(len, M_BLUETOOTH, M_NOWAIT);
1115 	if (data == NULL)
1116 		return;
1117 
1118 	m_copydata(m, 0, len, data);
1119 	rfcomm_session_send_mcc(rs, 0, RFCOMM_MCC_TEST, data, len);
1120 	kfree(data, M_BLUETOOTH);
1121 }
1122 
1123 /*
1124  * process Flow Control ON command/response
1125  */
1126 static void
1127 rfcomm_session_recv_mcc_fcon(struct rfcomm_session *rs, int cr)
1128 {
1129 
1130 	if (cr == 0)	/* ignore ack */
1131 		return;
1132 
1133 	rs->rs_flags |= RFCOMM_SESSION_RFC;
1134 	rfcomm_session_send_mcc(rs, 0, RFCOMM_MCC_FCON, NULL, 0);
1135 }
1136 
1137 /*
1138  * process Flow Control OFF command/response
1139  */
1140 static void
1141 rfcomm_session_recv_mcc_fcoff(struct rfcomm_session *rs, int cr)
1142 {
1143 	if (cr == 0)	/* ignore ack */
1144 		return;
1145 
1146 	rs->rs_flags &= ~RFCOMM_SESSION_RFC;
1147 	rfcomm_session_send_mcc(rs, 0, RFCOMM_MCC_FCOFF, NULL, 0);
1148 }
1149 
1150 /*
1151  * process Modem Status Command command/response
1152  */
1153 static void
1154 rfcomm_session_recv_mcc_msc(struct rfcomm_session *rs, int cr, struct mbuf *m)
1155 {
1156 	struct rfcomm_mcc_msc msc;	/* (3 octets) */
1157 	struct rfcomm_dlc *dlc;
1158 	int len = 0;
1159 
1160 	/* [ADDRESS] */
1161 	if (m->m_pkthdr.len < sizeof(msc.address))
1162 		return;
1163 
1164 	m_copydata(m, 0, sizeof(msc.address), &msc.address);
1165 	m_adj(m, sizeof(msc.address));
1166 	len += sizeof(msc.address);
1167 
1168 	dlc = rfcomm_dlc_lookup(rs, RFCOMM_DLCI(msc.address));
1169 
1170 	if (cr == 0) {	/* ignore acks */
1171 		if (dlc != NULL)
1172 			callout_stop(&dlc->rd_timeout);
1173 
1174 		return;
1175 	}
1176 
1177 	if (dlc == NULL) {
1178 		rfcomm_session_send_frame(rs, RFCOMM_FRAME_DM,
1179 						RFCOMM_DLCI(msc.address));
1180 		return;
1181 	}
1182 
1183 	/* [SIGNALS] */
1184 	if (m->m_pkthdr.len < sizeof(msc.modem))
1185 		return;
1186 
1187 	m_copydata(m, 0, sizeof(msc.modem), &msc.modem);
1188 	m_adj(m, sizeof(msc.modem));
1189 	len += sizeof(msc.modem);
1190 
1191 	dlc->rd_rmodem = msc.modem;
1192 	/* XXX how do we signal this upstream? */
1193 
1194 	if (RFCOMM_EA(msc.modem) == 0) {
1195 		if (m->m_pkthdr.len < sizeof(msc.brk))
1196 			return;
1197 
1198 		m_copydata(m, 0, sizeof(msc.brk), &msc.brk);
1199 		m_adj(m, sizeof(msc.brk));
1200 		len += sizeof(msc.brk);
1201 
1202 		/* XXX how do we signal this upstream? */
1203 	}
1204 
1205 	rfcomm_session_send_mcc(rs, 0, RFCOMM_MCC_MSC, &msc, len);
1206 }
1207 
1208 /*
1209  * process Remote Port Negotiation command/response
1210  */
1211 static void
1212 rfcomm_session_recv_mcc_rpn(struct rfcomm_session *rs, int cr, struct mbuf *m)
1213 {
1214 	struct rfcomm_mcc_rpn rpn;
1215 	uint16_t mask;
1216 
1217 	if (cr == 0)	/* ignore ack */
1218 		return;
1219 
1220 	/* default values */
1221 	rpn.bit_rate = RFCOMM_RPN_BR_9600;
1222 	rpn.line_settings = RFCOMM_RPN_8_N_1;
1223 	rpn.flow_control = RFCOMM_RPN_FLOW_NONE;
1224 	rpn.xon_char = RFCOMM_RPN_XON_CHAR;
1225 	rpn.xoff_char = RFCOMM_RPN_XOFF_CHAR;
1226 
1227 	if (m->m_pkthdr.len == sizeof(rpn)) {
1228 		m_copydata(m, 0, sizeof(rpn), (caddr_t)&rpn);
1229 		rpn.param_mask = RFCOMM_RPN_PM_ALL;
1230 	} else if (m->m_pkthdr.len == 1) {
1231 		m_copydata(m, 0, 1, (caddr_t)&rpn);
1232 		rpn.param_mask = letoh16(rpn.param_mask);
1233 	} else {
1234 		DPRINTF("Bad RPN length (%d)\n", m->m_pkthdr.len);
1235 		return;
1236 	}
1237 
1238 	mask = 0;
1239 
1240 	if (rpn.param_mask & RFCOMM_RPN_PM_RATE)
1241 		mask |= RFCOMM_RPN_PM_RATE;
1242 
1243 	if (rpn.param_mask & RFCOMM_RPN_PM_DATA
1244 	    && RFCOMM_RPN_DATA_BITS(rpn.line_settings) == RFCOMM_RPN_DATA_8)
1245 		mask |= RFCOMM_RPN_PM_DATA;
1246 
1247 	if (rpn.param_mask & RFCOMM_RPN_PM_STOP
1248 	    && RFCOMM_RPN_STOP_BITS(rpn.line_settings) == RFCOMM_RPN_STOP_1)
1249 		mask |= RFCOMM_RPN_PM_STOP;
1250 
1251 	if (rpn.param_mask & RFCOMM_RPN_PM_PARITY
1252 	    && RFCOMM_RPN_PARITY(rpn.line_settings) == RFCOMM_RPN_PARITY_NONE)
1253 		mask |= RFCOMM_RPN_PM_PARITY;
1254 
1255 	if (rpn.param_mask & RFCOMM_RPN_PM_XON
1256 	    && rpn.xon_char == RFCOMM_RPN_XON_CHAR)
1257 		mask |= RFCOMM_RPN_PM_XON;
1258 
1259 	if (rpn.param_mask & RFCOMM_RPN_PM_XOFF
1260 	    && rpn.xoff_char == RFCOMM_RPN_XOFF_CHAR)
1261 		mask |= RFCOMM_RPN_PM_XOFF;
1262 
1263 	if (rpn.param_mask & RFCOMM_RPN_PM_FLOW
1264 	    && rpn.flow_control == RFCOMM_RPN_FLOW_NONE)
1265 		mask |= RFCOMM_RPN_PM_FLOW;
1266 
1267 	rpn.param_mask = htole16(mask);
1268 
1269 	rfcomm_session_send_mcc(rs, 0, RFCOMM_MCC_RPN, &rpn, sizeof(rpn));
1270 }
1271 
1272 /*
1273  * process Remote Line Status command/response
1274  */
1275 static void
1276 rfcomm_session_recv_mcc_rls(struct rfcomm_session *rs, int cr, struct mbuf *m)
1277 {
1278 	struct rfcomm_mcc_rls rls;
1279 
1280 	if (cr == 0)	/* ignore ack */
1281 		return;
1282 
1283 	if (m->m_pkthdr.len != sizeof(rls)) {
1284 		DPRINTF("Bad RLS length %d\n", m->m_pkthdr.len);
1285 		return;
1286 	}
1287 
1288 	m_copydata(m, 0, sizeof(rls), (caddr_t)&rls);
1289 
1290 	/*
1291 	 * So far as I can tell, we just send back what
1292 	 * they sent us. This signifies errors that seem
1293 	 * irrelevent for RFCOMM over L2CAP.
1294 	 */
1295 	rls.address |= 0x03;	/* EA = 1, CR = 1 */
1296 	rls.status &= 0x0f;	/* only 4 bits valid */
1297 
1298 	rfcomm_session_send_mcc(rs, 0, RFCOMM_MCC_RLS, &rls, sizeof(rls));
1299 }
1300 
1301 /*
1302  * process Parameter Negotiation command/response
1303  */
1304 static void
1305 rfcomm_session_recv_mcc_pn(struct rfcomm_session *rs, int cr, struct mbuf *m)
1306 {
1307 	struct rfcomm_dlc *dlc;
1308 	struct rfcomm_mcc_pn pn;
1309 	int err;
1310 
1311 	if (m->m_pkthdr.len != sizeof(pn)) {
1312 		DPRINTF("Bad PN length %d\n", m->m_pkthdr.len);
1313 		return;
1314 	}
1315 
1316 	m_copydata(m, 0, sizeof(pn), (caddr_t)&pn);
1317 
1318 	pn.dlci &= 0x3f;
1319 	pn.mtu = letoh16(pn.mtu);
1320 
1321 	dlc = rfcomm_dlc_lookup(rs, pn.dlci);
1322 	if (cr) {	/* Command */
1323 		/*
1324 		 * If there is no DLC present, this is a new
1325 		 * connection so attempt to make one
1326 		 */
1327 		if (dlc == NULL) {
1328 			dlc = rfcomm_dlc_newconn(rs, pn.dlci);
1329 			if (dlc == NULL)
1330 				return;	/* (DM is sent) */
1331 		}
1332 
1333 		/* accept any valid MTU, and offer it back */
1334 		pn.mtu = min(pn.mtu, RFCOMM_MTU_MAX);
1335 		pn.mtu = min(pn.mtu, rs->rs_mtu);
1336 		pn.mtu = max(pn.mtu, RFCOMM_MTU_MIN);
1337 		dlc->rd_mtu = pn.mtu;
1338 		pn.mtu = htole16(pn.mtu);
1339 
1340 		/* credits are only set before DLC is open */
1341 		if (dlc->rd_state == RFCOMM_DLC_WAIT_CONNECT
1342 		    && (pn.flow_control & 0xf0) == 0xf0) {
1343 			rs->rs_flags |= RFCOMM_SESSION_CFC;
1344 			dlc->rd_txcred = pn.credits & 0x07;
1345 
1346 			dlc->rd_rxcred = (dlc->rd_rxsize / dlc->rd_mtu);
1347 			dlc->rd_rxcred = min(dlc->rd_rxcred,
1348 						RFCOMM_CREDITS_DEFAULT);
1349 
1350 			pn.flow_control = 0xe0;
1351 			pn.credits = dlc->rd_rxcred;
1352 		} else {
1353 			pn.flow_control = 0x00;
1354 			pn.credits = 0x00;
1355 		}
1356 
1357 		/* unused fields must be ignored and set to zero */
1358 		pn.ack_timer = 0;
1359 		pn.max_retrans = 0;
1360 
1361 		/* send our response */
1362 		err = rfcomm_session_send_mcc(rs, 0,
1363 					RFCOMM_MCC_PN, &pn, sizeof(pn));
1364 		if (err)
1365 			goto close;
1366 
1367 	} else {	/* Response */
1368 		/* ignore responses with no matching DLC */
1369 		if (dlc == NULL)
1370 			return;
1371 
1372 		callout_stop(&dlc->rd_timeout);
1373 
1374 		if (pn.mtu > RFCOMM_MTU_MAX || pn.mtu > dlc->rd_mtu) {
1375 			dlc->rd_state = RFCOMM_DLC_WAIT_DISCONNECT;
1376 			err = rfcomm_session_send_frame(rs, RFCOMM_FRAME_DISC,
1377 							pn.dlci);
1378 			if (err)
1379 				goto close;
1380 
1381 			callout_reset(&dlc->rd_timeout, rfcomm_ack_timeout * hz,
1382 				    rfcomm_dlc_timeout, dlc);
1383 			return;
1384 		}
1385 		dlc->rd_mtu = pn.mtu;
1386 
1387 		/* if DLC is not waiting to connect, we are done */
1388 		if (dlc->rd_state != RFCOMM_DLC_WAIT_CONNECT)
1389 			return;
1390 
1391 		/* set initial credits according to RFCOMM spec */
1392 		if ((pn.flow_control & 0xf0) == 0xe0) {
1393 			rs->rs_flags |= RFCOMM_SESSION_CFC;
1394 			dlc->rd_txcred = (pn.credits & 0x07);
1395 		}
1396 
1397 		callout_reset(&dlc->rd_timeout, rfcomm_ack_timeout * hz,
1398 				    rfcomm_dlc_timeout, dlc);
1399 
1400 		/* set link mode */
1401 		err = rfcomm_dlc_setmode(dlc);
1402 		if (err == EINPROGRESS) {
1403 			dlc->rd_state = RFCOMM_DLC_WAIT_SEND_SABM;
1404 			(*dlc->rd_proto->connecting)(dlc->rd_upper);
1405 			return;
1406 		}
1407 		if (err)
1408 			goto close;
1409 
1410 		/* we can proceed now */
1411 		err = rfcomm_session_send_frame(rs, RFCOMM_FRAME_SABM, pn.dlci);
1412 		if (err)
1413 			goto close;
1414 
1415 		dlc->rd_state = RFCOMM_DLC_WAIT_RECV_UA;
1416 	}
1417 	return;
1418 
1419 close:
1420 	rfcomm_dlc_close(dlc, err);
1421 }
1422 
1423 /*
1424  * process Non Supported Command command/response
1425  */
1426 static void
1427 rfcomm_session_recv_mcc_nsc(struct rfcomm_session *rs,
1428     int cr, struct mbuf *m)
1429 {
1430 	struct rfcomm_dlc *dlc, *next;
1431 
1432 	/*
1433 	 * Since we did nothing that is not mandatory,
1434 	 * we just abort the whole session..
1435 	 */
1436 
1437 	next = LIST_FIRST(&rs->rs_dlcs);
1438 	while ((dlc = next) != NULL) {
1439 		next = LIST_NEXT(dlc, rd_next);
1440 		rfcomm_dlc_close(dlc, ECONNABORTED);
1441 	}
1442 
1443 	rfcomm_session_free(rs);
1444 }
1445 
1446 /***********************************************************************
1447  *
1448  *	RFCOMM Session outward frame/uih/mcc building
1449  */
1450 
1451 /*
1452  * SABM/DISC/DM/UA frames are all minimal and mostly identical.
1453  */
1454 int
1455 rfcomm_session_send_frame(struct rfcomm_session *rs, int type, int dlci)
1456 {
1457 	struct rfcomm_cmd_hdr *hdr;
1458 	struct rfcomm_credit *credit;
1459 	struct mbuf *m;
1460 	uint8_t fcs, cr;
1461 
1462 	credit = pool_get(&rfcomm_credit_pool, PR_NOWAIT);
1463 	if (credit == NULL)
1464 		return ENOMEM;
1465 
1466 	m = m_gethdr(MB_DONTWAIT, MT_DATA);
1467 	if (m == NULL) {
1468 		pool_put(&rfcomm_credit_pool, credit);
1469 		return ENOMEM;
1470 	}
1471 
1472 	/*
1473 	 * The CR (command/response) bit identifies the frame either as a
1474 	 * commmand or a response and is used along with the DLCI to form
1475 	 * the address. Commands contain the non-initiator address, whereas
1476 	 * responses contain the initiator address, so the CR value is
1477 	 * also dependent on the session direction.
1478 	 */
1479 	if (type == RFCOMM_FRAME_UA || type == RFCOMM_FRAME_DM)
1480 		cr = IS_INITIATOR(rs) ? 0 : 1;
1481 	else
1482 		cr = IS_INITIATOR(rs) ? 1 : 0;
1483 
1484 	hdr = mtod(m, struct rfcomm_cmd_hdr *);
1485 	hdr->address = RFCOMM_MKADDRESS(cr, dlci);
1486 	hdr->control = RFCOMM_MKCONTROL(type, 1);   /* PF = 1 */
1487 	hdr->length = (0x00 << 1) | 0x01;	    /* len = 0x00, EA = 1 */
1488 
1489 	fcs = 0xff;
1490 	fcs = FCS(fcs, hdr->address);
1491 	fcs = FCS(fcs, hdr->control);
1492 	fcs = FCS(fcs, hdr->length);
1493 	fcs = 0xff - fcs;	/* ones complement */
1494 	hdr->fcs = fcs;
1495 
1496 	m->m_pkthdr.len = m->m_len = sizeof(struct rfcomm_cmd_hdr);
1497 
1498 	/* empty credit note */
1499 	credit->rc_dlc = NULL;
1500 	credit->rc_len = m->m_pkthdr.len;
1501 	STAILQ_INSERT_TAIL(&rs->rs_credits, credit, rc_next);
1502 
1503 	DPRINTFN(5, "dlci %d type %2.2x (%d bytes, fcs=%#2.2x)\n",
1504 		dlci, type, m->m_pkthdr.len, fcs);
1505 
1506 	return l2cap_send(rs->rs_l2cap, m);
1507 }
1508 
1509 /*
1510  * rfcomm_session_send_uih(rfcomm_session, rfcomm_dlc, credits, mbuf)
1511  *
1512  * UIH frame is per DLC data or Multiplexer Control Commands
1513  * when no DLC is given. Data mbuf is optional (just credits
1514  * will be sent in that case)
1515  */
1516 int
1517 rfcomm_session_send_uih(struct rfcomm_session *rs, struct rfcomm_dlc *dlc,
1518 			int credits, struct mbuf *m)
1519 {
1520 	struct rfcomm_credit *credit;
1521 	struct mbuf *m0 = NULL;
1522 	int err, len;
1523 	uint8_t fcs, *hdr;
1524 
1525 	KKASSERT(rs != NULL);
1526 
1527 	len = (m == NULL) ? 0 : m->m_pkthdr.len;
1528 	KKASSERT(!(credits == 0 && len == 0));
1529 
1530 	/*
1531 	 * Make a credit note for the completion notification
1532 	 */
1533 	credit = pool_get(&rfcomm_credit_pool, PR_NOWAIT);
1534 	if (credit == NULL)
1535 		goto nomem;
1536 
1537 	credit->rc_len = len;
1538 	credit->rc_dlc = dlc;
1539 
1540 	/*
1541 	 * Wrap UIH frame information around payload.
1542 	 *
1543 	 * [ADDRESS] [CONTROL] [LENGTH] [CREDITS] [...] [FCS]
1544 	 *
1545 	 * Address is one octet.
1546 	 * Control is one octet.
1547 	 * Length is one or two octets.
1548 	 * Credits may be one octet.
1549 	 *
1550 	 * FCS is one octet and calculated on address and
1551 	 *	control octets only.
1552 	 *
1553 	 * If there are credits to be sent, we will set the PF
1554 	 * flag and include them in the frame.
1555 	 */
1556 	m0 = m_gethdr(MB_DONTWAIT, MT_DATA);
1557 	if (m0 == NULL)
1558 		goto nomem;
1559 
1560 	MH_ALIGN(m0, 5);	/* (max 5 header octets) */
1561 	hdr = mtod(m0, uint8_t *);
1562 
1563 	/* CR bit is set according to the initiator of the session */
1564 	*hdr = RFCOMM_MKADDRESS((IS_INITIATOR(rs) ? 1 : 0),
1565 				(dlc ? dlc->rd_dlci : 0));
1566 	fcs = FCS(0xff, *hdr);
1567 	hdr++;
1568 
1569 	/* PF bit is set if credits are being sent */
1570 	*hdr = RFCOMM_MKCONTROL(RFCOMM_FRAME_UIH, (credits > 0 ? 1 : 0));
1571 	fcs = FCS(fcs, *hdr);
1572 	hdr++;
1573 
1574 	if (len < (1 << 7)) {
1575 		*hdr++ = ((len << 1) & 0xfe) | 0x01;	/* 7 bits, EA = 1 */
1576 	} else {
1577 		*hdr++ = ((len << 1) & 0xfe);		/* 7 bits, EA = 0 */
1578 		*hdr++ = ((len >> 7) & 0xff);		/* 8 bits, no EA */
1579 	}
1580 
1581 	if (credits > 0)
1582 		*hdr++ = (uint8_t)credits;
1583 
1584 	m0->m_len = hdr - mtod(m0, uint8_t *);
1585 
1586 	/* Append payload */
1587 	m0->m_next = m;
1588 	m = NULL;
1589 
1590 	m0->m_pkthdr.len = m0->m_len + len;
1591 
1592 	/* Append FCS */
1593 	fcs = 0xff - fcs;	/* ones complement */
1594 	len = m0->m_pkthdr.len;
1595 	m_copyback(m0, len, sizeof(fcs), &fcs);
1596 	if (m0->m_pkthdr.len != len + sizeof(fcs))
1597 		goto nomem;
1598 
1599 	DPRINTFN(10, "dlci %d, pktlen %d (%d data, %d credits), fcs=%#2.2x\n",
1600 		dlc ? dlc->rd_dlci : 0, m0->m_pkthdr.len, credit->rc_len,
1601 		credits, fcs);
1602 
1603 	/*
1604 	 * UIH frame ready to go..
1605 	 */
1606 	err = l2cap_send(rs->rs_l2cap, m0);
1607 	if (err)
1608 		goto fail;
1609 
1610 	STAILQ_INSERT_TAIL(&rs->rs_credits, credit, rc_next);
1611 	return 0;
1612 
1613 nomem:
1614 	err = ENOMEM;
1615 
1616 	if (m0 != NULL)
1617 		m_freem(m0);
1618 
1619 	if (m != NULL)
1620 		m_freem(m);
1621 
1622 fail:
1623 	if (credit != NULL)
1624 		pool_put(&rfcomm_credit_pool, credit);
1625 
1626 	return err;
1627 }
1628 
1629 /*
1630  * send Multiplexer Control Command (or Response) on session
1631  */
1632 int
1633 rfcomm_session_send_mcc(struct rfcomm_session *rs, int cr,
1634 			uint8_t type, void *data, int len)
1635 {
1636 	struct mbuf *m;
1637 	uint8_t *hdr;
1638 	int hlen;
1639 
1640 	m = m_gethdr(MB_DONTWAIT, MT_DATA);
1641 	if (m == NULL)
1642 		return ENOMEM;
1643 
1644 	hdr = mtod(m, uint8_t *);
1645 
1646 	/*
1647 	 * Technically the type field can extend past one octet, but none
1648 	 * currently defined will do that.
1649 	 */
1650 	*hdr++ = RFCOMM_MKMCC_TYPE(cr, type);
1651 
1652 	/*
1653 	 * In the frame, the max length size is 2 octets (15 bits) whereas
1654 	 * no max length size is specified for MCC commands. We must allow
1655 	 * for 3 octets since for MCC frames we use 7 bits + EA in each.
1656 	 *
1657 	 * Only test data can possibly be that big.
1658 	 *
1659 	 * XXX Should we check this against the MTU?
1660 	 */
1661 	if (len < (1 << 7)) {
1662 		*hdr++ = ((len << 1) & 0xfe) | 0x01;	/* 7 bits, EA = 1 */
1663 	} else if (len < (1 << 14)) {
1664 		*hdr++ = ((len << 1) & 0xfe);		/* 7 bits, EA = 0 */
1665 		*hdr++ = ((len >> 6) & 0xfe) | 0x01;	/* 7 bits, EA = 1 */
1666 	} else if (len < (1 << 15)) {
1667 		*hdr++ = ((len << 1) & 0xfe);		/* 7 bits, EA = 0 */
1668 		*hdr++ = ((len >> 6) & 0xfe);		/* 7 bits, EA = 0 */
1669 		*hdr++ = ((len >> 13) & 0x02) | 0x01;	/* 1 bit,  EA = 1 */
1670 	} else {
1671 		DPRINTF("incredible length! (%d)\n", len);
1672 		m_freem(m);
1673 		return EMSGSIZE;
1674 	}
1675 
1676 	/*
1677 	 * add command data (to same mbuf if possible)
1678 	 */
1679 	hlen = hdr - mtod(m, uint8_t *);
1680 
1681 	if (len > 0) {
1682 		m->m_pkthdr.len = m->m_len = MHLEN;
1683 		m_copyback(m, hlen, len, data);
1684 		if (m->m_pkthdr.len != max(MHLEN, hlen + len)) {
1685 			m_freem(m);
1686 			return ENOMEM;
1687 		}
1688 	}
1689 
1690 	m->m_pkthdr.len = hlen + len;
1691 	m->m_len = min(MHLEN, m->m_pkthdr.len);
1692 
1693 	DPRINTFN(5, "%s type %2.2x len %d\n",
1694 		(cr ? "command" : "response"), type, m->m_pkthdr.len);
1695 
1696 	return rfcomm_session_send_uih(rs, NULL, 0, m);
1697 }
1698