xref: /netbsd-src/usr.bin/rfcomm_sppd/rfcomm_sppd.c (revision abb0f93cd77b67f080613360c65701f85e5f5cfe)
1 /*	$NetBSD: rfcomm_sppd.c,v 1.12 2009/09/24 18:30:37 plunky Exp $	*/
2 
3 /*-
4  * Copyright (c) 2006 Itronix Inc.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. The name of Itronix Inc. may not be used to endorse
16  *    or promote products derived from this software without specific
17  *    prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY ITRONIX INC. ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL ITRONIX INC. BE LIABLE FOR ANY
23  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
24  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
25  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
26  * ON ANY THEORY OF LIABILITY, WHETHER IN
27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29  * POSSIBILITY OF SUCH DAMAGE.
30  */
31 /*
32  * Copyright (c) 2009 The NetBSD Foundation, Inc.
33  * Copyright (c) 2007 Iain Hibbert
34  * Copyright (c) 2003 Maksim Yevmenkin <m_evmenkin@yahoo.com>
35  * All rights reserved.
36  *
37  * Redistribution and use in source and binary forms, with or without
38  * modification, are permitted provided that the following conditions
39  * are met:
40  * 1. Redistributions of source code must retain the above copyright
41  *    notice, this list of conditions and the following disclaimer.
42  * 2. Redistributions in binary form must reproduce the above copyright
43  *    notice, this list of conditions and the following disclaimer in the
44  *    documentation and/or other materials provided with the distribution.
45  *
46  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
47  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
48  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
49  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
50  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
51  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
52  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
53  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
54  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
55  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
56  * SUCH DAMAGE.
57  */
58 
59 #include <sys/cdefs.h>
60 __COPYRIGHT("@(#) Copyright (c) 2009 The NetBSD Foundation, Inc.\
61   Copyright (c) 2007 Iain Hibbert.\
62   Copyright (c) 2006 Itronix, Inc.\
63   Copyright (c) 2003 Maksim Yevmenkin m_evmenkin@yahoo.com.\
64   All rights reserved.");
65 __RCSID("$NetBSD: rfcomm_sppd.c,v 1.12 2009/09/24 18:30:37 plunky Exp $");
66 
67 #include <sys/param.h>
68 
69 #include <bluetooth.h>
70 #include <ctype.h>
71 #include <err.h>
72 #include <errno.h>
73 #include <fcntl.h>
74 #include <grp.h>
75 #include <limits.h>
76 #include <paths.h>
77 #include <sdp.h>
78 #include <signal.h>
79 #include <stdarg.h>
80 #include <stdio.h>
81 #include <stdlib.h>
82 #include <string.h>
83 #include <syslog.h>
84 #include <termios.h>
85 #include <unistd.h>
86 
87 #include <netbt/rfcomm.h>
88 
89 int open_tty(const char *);
90 int open_client(bdaddr_t *, bdaddr_t *, int, uintmax_t, const char *);
91 int open_server(bdaddr_t *, uint16_t, uint8_t, int, const char *);
92 void copy_data(int, int);
93 int service_search(const bdaddr_t *, const bdaddr_t *, uint16_t, uintmax_t *, uintmax_t *);
94 void sighandler(int);
95 void usage(void);
96 void reset_tio(void);
97 
98 int done;		/* got a signal */
99 struct termios tio;	/* stored termios for reset on exit */
100 
101 struct service {
102 	const char *	name;
103 	const char *	description;
104 	uint16_t	class;
105 } services[] = {
106 	{ "DUN",	"Dialup Networking",
107 	    SDP_SERVICE_CLASS_DIALUP_NETWORKING		},
108 	{ "LAN",	"LAN access using PPP",
109 	    SDP_SERVICE_CLASS_LAN_ACCESS_USING_PPP	},
110 	{ "SP",		"Serial Port",
111 	    SDP_SERVICE_CLASS_SERIAL_PORT		},
112 	{ NULL,		NULL,		0		}
113 };
114 
115 int
116 main(int argc, char *argv[])
117 {
118 	struct termios		t;
119 	bdaddr_t		laddr, raddr;
120 	fd_set			rdset;
121 	const char		*service;
122 	char			*ep, *tty;
123 	int			lm, n, rfcomm, tty_in, tty_out;
124 	uint16_t		psm;
125 	uint8_t			channel;
126 
127 	bdaddr_copy(&laddr, BDADDR_ANY);
128 	bdaddr_copy(&raddr, BDADDR_ANY);
129 	service = "SP";
130 	tty = NULL;
131 	channel = 0;
132 	psm = L2CAP_PSM_RFCOMM;
133 	lm = 0;
134 
135 	/* Parse command line options */
136 	while ((n = getopt(argc, argv, "a:c:d:hm:p:s:t:")) != -1) {
137 		switch (n) {
138 		case 'a': /* remote device address */
139 			if (!bt_aton(optarg, &raddr)) {
140 				struct hostent	*he = NULL;
141 
142 				if ((he = bt_gethostbyname(optarg)) == NULL)
143 					errx(EXIT_FAILURE, "%s: %s", optarg,
144 					    hstrerror(h_errno));
145 
146 				bdaddr_copy(&raddr, (bdaddr_t *)he->h_addr);
147 			}
148 			break;
149 
150 		case 'c': /* RFCOMM channel */
151 			channel = strtoul(optarg, &ep, 10);
152 			if (*ep != '\0' || channel < 1 || channel > 30)
153 				errx(EXIT_FAILURE, "Invalid channel: %s", optarg);
154 
155 			break;
156 
157 		case 'd': /* local device address */
158 			if (!bt_devaddr(optarg, &laddr))
159 				err(EXIT_FAILURE, "%s", optarg);
160 
161 			break;
162 
163 		case 'm': /* Link Mode */
164 			if (strcasecmp(optarg, "auth") == 0)
165 				lm = RFCOMM_LM_AUTH;
166 			else if (strcasecmp(optarg, "encrypt") == 0)
167 				lm = RFCOMM_LM_ENCRYPT;
168 			else if (strcasecmp(optarg, "secure") == 0)
169 				lm = RFCOMM_LM_SECURE;
170 			else
171 				errx(EXIT_FAILURE, "%s: unknown mode", optarg);
172 
173 			break;
174 
175 		case 'p': /* PSM */
176 			psm = strtoul(optarg, &ep, 0);
177 			if (*ep != '\0' || L2CAP_PSM_INVALID(psm))
178 				errx(EXIT_FAILURE, "Invalid PSM: %s", optarg);
179 
180 			break;
181 
182 		case 's': /* service class */
183 			service = optarg;
184 			break;
185 
186 		case 't': /* Slave TTY name */
187 			if (optarg[0] != '/')
188 				asprintf(&tty, "%s%s", _PATH_DEV, optarg);
189 			else
190 				tty = optarg;
191 
192 			break;
193 
194 		case 'h':
195 		default:
196 			usage();
197 			/* NOT REACHED */
198 		}
199 	}
200 
201 	/*
202 	 * validate options:
203 	 *	must have channel or remote address but not both
204 	 */
205 	if ((channel == 0 && bdaddr_any(&raddr))
206 	    || (channel != 0 && !bdaddr_any(&raddr)))
207 		usage();
208 
209 	/*
210 	 * grab ttys before we start the bluetooth
211 	 */
212 	if (tty == NULL) {
213 		tty_in = STDIN_FILENO;
214 		tty_out = STDOUT_FILENO;
215 	} else {
216 		tty_in = open_tty(tty);
217 		tty_out = tty_in;
218 	}
219 
220 	/* open RFCOMM */
221 	if (channel == 0)
222 		rfcomm = open_client(&laddr, &raddr, lm, psm, service);
223 	else
224 		rfcomm = open_server(&laddr, psm, channel, lm, service);
225 
226 	/*
227 	 * now we are ready to go, so either detach or maybe turn
228 	 * off some input processing, so that rfcomm_sppd can
229 	 * be used directly with stdio
230 	 */
231 	if (tty == NULL) {
232 		if (tcgetattr(tty_in, &t) < 0)
233 			err(EXIT_FAILURE, "tcgetattr");
234 
235 		memcpy(&tio, &t, sizeof(tio));
236 		t.c_lflag &= ~(ECHO | ICANON);
237 		t.c_iflag &= ~(ICRNL);
238 
239 		if (memcmp(&tio, &t, sizeof(tio))) {
240 			if (tcsetattr(tty_in, TCSANOW, &t) < 0)
241 				err(EXIT_FAILURE, "tcsetattr");
242 
243 			atexit(reset_tio);
244 		}
245 	} else {
246 		if (daemon(0, 0) < 0)
247 			err(EXIT_FAILURE, "daemon() failed");
248 	}
249 
250 	/* catch signals */
251 	done = 0;
252 	(void)signal(SIGHUP, sighandler);
253 	(void)signal(SIGINT, sighandler);
254 	(void)signal(SIGPIPE, sighandler);
255 	(void)signal(SIGTERM, sighandler);
256 
257 	openlog(getprogname(), LOG_PERROR | LOG_PID, LOG_DAEMON);
258 	syslog(LOG_INFO, "Starting on %s...", (tty ? tty : "stdio"));
259 
260 	n = MAX(tty_in, rfcomm) + 1;
261 	while (!done) {
262 		FD_ZERO(&rdset);
263 		FD_SET(tty_in, &rdset);
264 		FD_SET(rfcomm, &rdset);
265 
266 		if (select(n, &rdset, NULL, NULL, NULL) < 0) {
267 			if (errno == EINTR)
268 				continue;
269 
270 			syslog(LOG_ERR, "select error: %m");
271 			exit(EXIT_FAILURE);
272 		}
273 
274 		if (FD_ISSET(tty_in, &rdset))
275 			copy_data(tty_in, rfcomm);
276 
277 		if (FD_ISSET(rfcomm, &rdset))
278 			copy_data(rfcomm, tty_out);
279 	}
280 
281 	syslog(LOG_INFO, "Completed on %s", (tty ? tty : "stdio"));
282 	exit(EXIT_SUCCESS);
283 }
284 
285 int
286 open_tty(const char *tty)
287 {
288 	char		 pty[PATH_MAX], *slash;
289 	struct group	*gr = NULL;
290 	gid_t		 ttygid;
291 	int		 master;
292 
293 	/*
294 	 * Construct master PTY name. The slave tty name must be less then
295 	 * PATH_MAX characters in length, must contain '/' character and
296 	 * must not end with '/'.
297 	 */
298 	if (strlen(tty) >= sizeof(pty))
299 		errx(EXIT_FAILURE, ": tty name too long");
300 
301 	strlcpy(pty, tty, sizeof(pty));
302 	slash = strrchr(pty, '/');
303 	if (slash == NULL || slash[1] == '\0')
304 		errx(EXIT_FAILURE, "%s: invalid tty", tty);
305 
306 	slash[1] = 'p';
307 	if (strcmp(pty, tty) == 0)
308 		errx(EXIT_FAILURE, "Master and slave tty are the same (%s)", tty);
309 
310 	if ((master = open(pty, O_RDWR, 0)) < 0)
311 		err(EXIT_FAILURE, "%s", pty);
312 
313 	/*
314 	 * Slave TTY
315 	 */
316 
317 	if ((gr = getgrnam("tty")) != NULL)
318 		ttygid = gr->gr_gid;
319 	else
320 		ttygid = (gid_t)-1;
321 
322 	(void)chown(tty, getuid(), ttygid);
323 	(void)chmod(tty, S_IRUSR | S_IWUSR | S_IWGRP);
324 	(void)revoke(tty);
325 
326 	return master;
327 }
328 
329 int
330 open_client(bdaddr_t *laddr, bdaddr_t *raddr, int lm, uintmax_t psm, const char *service)
331 {
332 	struct sockaddr_bt sa;
333 	struct service *s;
334 	struct linger l;
335 	char *ep;
336 	int fd, error;
337 	uintmax_t channel;
338 
339 	for (s = services ; ; s++) {
340 		if (s->name == NULL) {
341 			channel = strtoul(service, &ep, 10);
342 			if (*ep != '\0')
343 				errx(EXIT_FAILURE, "Unknown service: %s", service);
344 
345 			break;
346 		}
347 
348 		if (strcasecmp(s->name, service) == 0) {
349 			error = service_search(laddr, raddr, s->class, &psm, &channel);
350 			if (error != 0)
351 				errx(EXIT_FAILURE, "%s: %s", s->name, strerror(error));
352 
353 			break;
354 		}
355 	}
356 
357 	if (channel < RFCOMM_CHANNEL_MIN || channel > RFCOMM_CHANNEL_MAX)
358 		errx(EXIT_FAILURE, "Invalid channel %"PRIuMAX, channel);
359 
360 	if (L2CAP_PSM_INVALID(psm))
361 		errx(EXIT_FAILURE, "Invalid PSM 0x%04"PRIxMAX, psm);
362 
363 	memset(&sa, 0, sizeof(sa));
364 	sa.bt_len = sizeof(sa);
365 	sa.bt_family = AF_BLUETOOTH;
366 	bdaddr_copy(&sa.bt_bdaddr, laddr);
367 
368 	fd = socket(PF_BLUETOOTH, SOCK_STREAM, BTPROTO_RFCOMM);
369 	if (fd < 0)
370 		err(EXIT_FAILURE, "socket()");
371 
372 	if (bind(fd, (struct sockaddr *)&sa, sizeof(sa)) < 0)
373 		err(EXIT_FAILURE, "bind(%s)", bt_ntoa(laddr, NULL));
374 
375 	memset(&l, 0, sizeof(l));
376 	l.l_onoff = 1;
377 	l.l_linger = 5;
378 	if (setsockopt(fd, SOL_SOCKET, SO_LINGER, &l, sizeof(l)) < 0)
379 		err(EXIT_FAILURE, "linger()");
380 
381 	if (setsockopt(fd, BTPROTO_RFCOMM, SO_RFCOMM_LM, &lm, sizeof(lm)) < 0)
382 		err(EXIT_FAILURE, "link mode");
383 
384 	sa.bt_psm = psm;
385 	sa.bt_channel = channel;
386 	bdaddr_copy(&sa.bt_bdaddr, raddr);
387 
388 	if (connect(fd, (struct sockaddr *)&sa, sizeof(sa)) < 0)
389 		err(EXIT_FAILURE, "connect(%s, 0x%04"PRIxMAX", %"PRIuMAX")",
390 		    bt_ntoa(raddr, NULL), psm, channel);
391 
392 	return fd;
393 }
394 
395 int
396 open_server(bdaddr_t *laddr, uint16_t psm, uint8_t channel, int lm, const char *service)
397 {
398 	uint8_t	buffer[256];
399 	struct sockaddr_bt sa;
400 	struct service *s;
401 	struct linger l;
402 	socklen_t len;
403 	sdp_session_t ss;
404 	sdp_data_t rec;
405 	int sv, fd;
406 
407 	for (s = services; ; s++) {
408 		if (s->name == NULL)
409 			usage();
410 
411 		if (strcasecmp(s->name, service) == 0)
412 			break;
413 	}
414 
415 	/* Open server socket */
416 	sv = socket(PF_BLUETOOTH, SOCK_STREAM, BTPROTO_RFCOMM);
417 	if (sv < 0)
418 		err(EXIT_FAILURE, "socket()");
419 
420 	memset(&sa, 0, sizeof(sa));
421 	sa.bt_len = sizeof(sa);
422 	sa.bt_family = AF_BLUETOOTH;
423 	sa.bt_psm = psm;
424 	sa.bt_channel = channel;
425 	bdaddr_copy(&sa.bt_bdaddr, laddr);
426 	if (bind(sv, (struct sockaddr *)&sa, sizeof(sa)) < 0)
427 		err(EXIT_FAILURE, "bind(%s, 0x%04x, %d)",
428 		    bt_ntoa(laddr, NULL), psm, channel);
429 
430 	if (setsockopt(sv, BTPROTO_RFCOMM, SO_RFCOMM_LM, &lm, sizeof(lm)) < 0)
431 		err(EXIT_FAILURE, "link mode");
432 
433 	if (listen(sv, 1) < 0)
434 		err(EXIT_FAILURE, "listen()");
435 
436 	/* Build SDP record */
437 	rec.next = buffer;
438 	rec.end = buffer + sizeof(buffer);
439 
440 	sdp_put_uint16(&rec, SDP_ATTR_SERVICE_RECORD_HANDLE);
441 	sdp_put_uint32(&rec, 0x00000000);
442 
443 	sdp_put_uint16(&rec, SDP_ATTR_SERVICE_CLASS_ID_LIST);
444 	sdp_put_seq(&rec, 3);
445 	sdp_put_uuid16(&rec, s->class);
446 
447 	len = (psm == L2CAP_PSM_RFCOMM ? 0 : 3);
448 
449 	sdp_put_uint16(&rec, SDP_ATTR_PROTOCOL_DESCRIPTOR_LIST);
450 	sdp_put_seq(&rec, 12 + len);
451 	sdp_put_seq(&rec, 3 + len);
452 	sdp_put_uuid16(&rec, SDP_UUID_PROTOCOL_L2CAP);
453 	if (len > 0)
454 		sdp_put_uint16(&rec, psm);
455 	sdp_put_seq(&rec, 5);
456 	sdp_put_uuid16(&rec, SDP_UUID_PROTOCOL_RFCOMM);
457 	sdp_put_uint8(&rec, channel);
458 
459 	sdp_put_uint16(&rec, SDP_ATTR_BROWSE_GROUP_LIST);
460 	sdp_put_seq(&rec, 3);
461 	sdp_put_uuid16(&rec, SDP_SERVICE_CLASS_PUBLIC_BROWSE_GROUP);
462 
463 	sdp_put_uint16(&rec, SDP_ATTR_LANGUAGE_BASE_ATTRIBUTE_ID_LIST);
464 	sdp_put_seq(&rec, 9);
465 	sdp_put_uint16(&rec, 0x656e);	/* "en" */
466 	sdp_put_uint16(&rec, 106);	/* UTF-8 */
467 	sdp_put_uint16(&rec, SDP_ATTR_PRIMARY_LANGUAGE_BASE_ID);
468 
469 	if (s->class == SDP_SERVICE_CLASS_LAN_ACCESS_USING_PPP) {
470 		sdp_put_uint16(&rec, SDP_ATTR_SERVICE_AVAILABILITY);
471 		sdp_put_uint8(&rec, 0x00);
472 	}
473 
474 	sdp_put_uint16(&rec, SDP_ATTR_BLUETOOTH_PROFILE_DESCRIPTOR_LIST);
475 	sdp_put_seq(&rec, 8);
476 	sdp_put_seq(&rec, 6);
477 	sdp_put_uuid16(&rec, s->class);
478 	sdp_put_uint16(&rec, 0x0100);	/* v1.0 */
479 
480 	sdp_put_uint16(&rec, SDP_ATTR_PRIMARY_LANGUAGE_BASE_ID
481 	    + SDP_ATTR_SERVICE_NAME_OFFSET);
482 	sdp_put_str(&rec, s->description, -1);
483 
484 	if (s->class == SDP_SERVICE_CLASS_DIALUP_NETWORKING) {
485 		sdp_put_uint16(&rec, SDP_ATTR_AUDIO_FEEDBACK_SUPPORT);
486 		sdp_put_bool(&rec, false);
487 	}
488 
489 #if 0
490 	if (s->class == SDP_SERVICE_CLASS_LAN_ACCESS_USING_PPP) {
491 		sdp_put_uint16(&rec, SDP_ATTR_IP_SUBNET);	/* TODO */
492 		sdp_put_str(&rec, "0.0.0.0/0", -1);
493 	}
494 #endif
495 
496 	rec.end = rec.next;
497 	rec.next = buffer;
498 
499 	/* Register service with SDP server */
500 	ss = sdp_open_local(NULL);
501 	if (ss == NULL)
502 		err(EXIT_FAILURE, "sdp_open_local");
503 
504 	if (!sdp_record_insert(ss, laddr, NULL, &rec))
505 		err(EXIT_FAILURE, "sdp_record_insert");
506 
507 	/* Accept client connection */
508 	len = sizeof(sa);
509 	fd = accept(sv, (struct sockaddr *)&sa, &len);
510 	if (fd < 0)
511 		err(EXIT_FAILURE, "accept");
512 
513 	memset(&l, 0, sizeof(l));
514 	l.l_onoff = 1;
515 	l.l_linger = 5;
516 	if (setsockopt(fd, SOL_SOCKET, SO_LINGER, &l, sizeof(l)) < 0)
517 		err(EXIT_FAILURE, "linger()");
518 
519 	close(sv);
520 	return fd;
521 }
522 
523 void
524 copy_data(int src, int dst)
525 {
526 	static char	buf[BUFSIZ];
527 	ssize_t		nr, nw, off;
528 
529 	while ((nr = read(src, buf, sizeof(buf))) == -1) {
530 		if (errno != EINTR) {
531 			syslog(LOG_ERR, "read failed: %m");
532 			exit(EXIT_FAILURE);
533 		}
534 	}
535 
536 	if (nr == 0)	/* reached EOF */
537 		done++;
538 
539 	for (off = 0 ; nr ; nr -= nw, off += nw) {
540 		if ((nw = write(dst, buf + off, (size_t)nr)) == -1) {
541 			syslog(LOG_ERR, "write failed: %m");
542 			exit(EXIT_FAILURE);
543 		}
544 	}
545 }
546 
547 int
548 service_search(bdaddr_t const *laddr, bdaddr_t const *raddr,
549     uint16_t class, uintmax_t *psm, uintmax_t *channel)
550 {
551 	uint8_t		buffer[6];	/* SSP (3 bytes) + AIL (3 bytes) */
552 	sdp_session_t	ss;
553 	sdp_data_t	ail, ssp, rsp, rec, value, pdl, seq;
554 	uint16_t	attr;
555 	bool		rv;
556 
557 	seq.next = buffer;
558 	seq.end = buffer + sizeof(buffer);
559 
560 	/*
561 	 * build ServiceSearchPattern (3 bytes)
562 	 */
563 	ssp.next = seq.next;
564 	sdp_put_uuid16(&seq, class);
565 	ssp.end = seq.next;
566 
567 	/*
568 	 * build AttributeIDList (3 bytes)
569 	 */
570 	ail.next = seq.next;
571 	sdp_put_uint16(&seq, SDP_ATTR_PROTOCOL_DESCRIPTOR_LIST);
572 	ail.end = seq.next;
573 
574 	ss = sdp_open(laddr, raddr);
575 	if (ss == NULL)
576 		return errno;
577 
578 	rv = sdp_service_search_attribute(ss, &ssp, &ail, &rsp);
579 	if (!rv) {
580 		sdp_close(ss);
581 		return errno;
582 	}
583 
584 	/*
585 	 * The response will be a list of records that matched our
586 	 * ServiceSearchPattern, where each record is a sequence
587 	 * containing a single ProtocolDescriptorList attribute and
588 	 * value
589 	 *
590 	 *	seq
591 	 *	  uint16	ProtocolDescriptorList
592 	 *	  value
593 	 *	seq
594 	 *	  uint16	ProtocolDescriptorList
595 	 *	  value
596 	 *
597 	 * If the ProtocolDescriptorList describes a single stack,
598 	 * the attribute value takes the form of a single Data Element
599 	 * Sequence where each member is a protocol descriptor.
600 	 *
601 	 *	seq
602 	 *	  list
603 	 *
604 	 * If it is possible for more than one kind of protocol
605 	 * stack to be used to gain access to the service, the
606 	 * ProtocolDescriptorList takes the form of a Data Element
607 	 * Alternative where each member is a Data Element Sequence
608 	 * describing an alternative protocol stack.
609 	 *
610 	 *	alt
611 	 *	  seq
612 	 *	    list
613 	 *	  seq
614 	 *	    list
615 	 *
616 	 * Each protocol stack description contains a sequence for each
617 	 * protocol, where each sequence contains the protocol UUID as
618 	 * the first element, and any ProtocolSpecificParameters. We are
619 	 * interested in the L2CAP psm if provided, and the RFCOMM channel
620 	 * number, stored as parameter#1 in each case.
621 	 *
622 	 *	seq
623 	 *	  uuid		L2CAP
624 	 *	  uint16	psm
625 	 *	seq
626 	 *	  uuid		RFCOMM
627 	 *	  uint8		channel
628 	 */
629 
630 	rv = false;
631 	while (!rv && sdp_get_seq(&rsp, &rec)) {
632 		if (!sdp_get_attr(&rec, &attr, &value)
633 		    || attr != SDP_ATTR_PROTOCOL_DESCRIPTOR_LIST)
634 			continue;
635 
636 		sdp_get_alt(&value, &value);	/* strip any alt container */
637 		while (!rv && sdp_get_seq(&value, &pdl)) {
638 			*psm = L2CAP_PSM_RFCOMM;
639 			if (sdp_get_seq(&pdl, &seq)
640 			    && sdp_match_uuid16(&seq, SDP_UUID_PROTOCOL_L2CAP)
641 			    && (sdp_get_uint(&seq, psm) || true)
642 			    && sdp_get_seq(&pdl, &seq)
643 			    && sdp_match_uuid16(&seq, SDP_UUID_PROTOCOL_RFCOMM)
644 			    && sdp_get_uint(&seq, channel))
645 				rv = true;
646 		}
647 	}
648 
649 	sdp_close(ss);
650 	return (rv) ? 0 : ENOATTR;
651 }
652 
653 void
654 sighandler(int s)
655 {
656 
657 	done++;
658 }
659 
660 void
661 reset_tio(void)
662 {
663 
664 	tcsetattr(STDIN_FILENO, TCSAFLUSH, &tio);
665 }
666 
667 void
668 usage(void)
669 {
670 	const char *cmd = getprogname();
671 	struct service *s;
672 
673 	fprintf(stderr, "Usage: %s [-d device] [-m mode] [-p psm] [-s service] [-t tty]\n"
674 			"       %*s {-a bdaddr | -c channel}\n"
675 			"\n"
676 			"Where:\n"
677 			"\t-a bdaddr    remote device address\n"
678 			"\t-c channel   local RFCOMM channel\n"
679 			"\t-d device    local device address\n"
680 			"\t-m mode      link mode\n"
681 			"\t-p psm       protocol/service multiplexer\n"
682 			"\t-s service   service class\n"
683 			"\t-t tty       run in background using pty\n"
684 			"\n", cmd, (int)strlen(cmd), "");
685 
686 	fprintf(stderr, "Known service classes:\n");
687 	for (s = services ; s->name != NULL ; s++)
688 		fprintf(stderr, "\t%-13s%s\n", s->name, s->description);
689 
690 	exit(EXIT_FAILURE);
691 }
692