xref: /netbsd-src/usr.bin/rfcomm_sppd/rfcomm_sppd.c (revision c2f76ff004a2cb67efe5b12d97bd3ef7fe89e18d)
1 /*	$NetBSD: rfcomm_sppd.c,v 1.13 2010/11/03 08:27:27 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 1.13 2010/11/03 08:27:27 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 = RFCOMM_CHANNEL_ANY;
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'
153 			    || channel < RFCOMM_CHANNEL_MIN
154 			    || channel > RFCOMM_CHANNEL_MAX)
155 				errx(EXIT_FAILURE, "Invalid channel: %s", optarg);
156 
157 			break;
158 
159 		case 'd': /* local device address */
160 			if (!bt_devaddr(optarg, &laddr))
161 				err(EXIT_FAILURE, "%s", optarg);
162 
163 			break;
164 
165 		case 'm': /* Link Mode */
166 			if (strcasecmp(optarg, "auth") == 0)
167 				lm = RFCOMM_LM_AUTH;
168 			else if (strcasecmp(optarg, "encrypt") == 0)
169 				lm = RFCOMM_LM_ENCRYPT;
170 			else if (strcasecmp(optarg, "secure") == 0)
171 				lm = RFCOMM_LM_SECURE;
172 			else
173 				errx(EXIT_FAILURE, "%s: unknown mode", optarg);
174 
175 			break;
176 
177 		case 'p': /* PSM */
178 			psm = strtoul(optarg, &ep, 0);
179 			if (*ep != '\0' || L2CAP_PSM_INVALID(psm))
180 				errx(EXIT_FAILURE, "Invalid PSM: %s", optarg);
181 
182 			break;
183 
184 		case 's': /* service class */
185 			service = optarg;
186 			break;
187 
188 		case 't': /* Slave TTY name */
189 			if (optarg[0] != '/')
190 				asprintf(&tty, "%s%s", _PATH_DEV, optarg);
191 			else
192 				tty = optarg;
193 
194 			break;
195 
196 		case 'h':
197 		default:
198 			usage();
199 			/* NOT REACHED */
200 		}
201 	}
202 
203 	/*
204 	 * validate options:
205 	 *	cannot have remote address if channel was given
206 	 */
207 	if (channel != RFCOMM_CHANNEL_ANY && !bdaddr_any(&raddr))
208 		usage();
209 
210 	/*
211 	 * grab ttys before we start the bluetooth
212 	 */
213 	if (tty == NULL) {
214 		tty_in = STDIN_FILENO;
215 		tty_out = STDOUT_FILENO;
216 	} else {
217 		tty_in = open_tty(tty);
218 		tty_out = tty_in;
219 	}
220 
221 	/* open RFCOMM */
222 	if (!bdaddr_any(&raddr))
223 		rfcomm = open_client(&laddr, &raddr, lm, psm, service);
224 	else
225 		rfcomm = open_server(&laddr, psm, channel, lm, service);
226 
227 	/*
228 	 * now we are ready to go, so either detach or maybe turn
229 	 * off some input processing, so that rfcomm_sppd can
230 	 * be used directly with stdio
231 	 */
232 	if (tty == NULL) {
233 		if (tcgetattr(tty_in, &t) < 0)
234 			err(EXIT_FAILURE, "tcgetattr");
235 
236 		memcpy(&tio, &t, sizeof(tio));
237 		t.c_lflag &= ~(ECHO | ICANON);
238 		t.c_iflag &= ~(ICRNL);
239 
240 		if (memcmp(&tio, &t, sizeof(tio))) {
241 			if (tcsetattr(tty_in, TCSANOW, &t) < 0)
242 				err(EXIT_FAILURE, "tcsetattr");
243 
244 			atexit(reset_tio);
245 		}
246 	} else {
247 		if (daemon(0, 0) < 0)
248 			err(EXIT_FAILURE, "daemon() failed");
249 	}
250 
251 	/* catch signals */
252 	done = 0;
253 	(void)signal(SIGHUP, sighandler);
254 	(void)signal(SIGINT, sighandler);
255 	(void)signal(SIGPIPE, sighandler);
256 	(void)signal(SIGTERM, sighandler);
257 
258 	openlog(getprogname(), LOG_PERROR | LOG_PID, LOG_DAEMON);
259 	syslog(LOG_INFO, "Starting on %s...", (tty ? tty : "stdio"));
260 
261 	n = MAX(tty_in, rfcomm) + 1;
262 	while (!done) {
263 		FD_ZERO(&rdset);
264 		FD_SET(tty_in, &rdset);
265 		FD_SET(rfcomm, &rdset);
266 
267 		if (select(n, &rdset, NULL, NULL, NULL) < 0) {
268 			if (errno == EINTR)
269 				continue;
270 
271 			syslog(LOG_ERR, "select error: %m");
272 			exit(EXIT_FAILURE);
273 		}
274 
275 		if (FD_ISSET(tty_in, &rdset))
276 			copy_data(tty_in, rfcomm);
277 
278 		if (FD_ISSET(rfcomm, &rdset))
279 			copy_data(rfcomm, tty_out);
280 	}
281 
282 	syslog(LOG_INFO, "Completed on %s", (tty ? tty : "stdio"));
283 	exit(EXIT_SUCCESS);
284 }
285 
286 int
287 open_tty(const char *tty)
288 {
289 	char		 pty[PATH_MAX], *slash;
290 	struct group	*gr = NULL;
291 	gid_t		 ttygid;
292 	int		 master;
293 
294 	/*
295 	 * Construct master PTY name. The slave tty name must be less then
296 	 * PATH_MAX characters in length, must contain '/' character and
297 	 * must not end with '/'.
298 	 */
299 	if (strlen(tty) >= sizeof(pty))
300 		errx(EXIT_FAILURE, ": tty name too long");
301 
302 	strlcpy(pty, tty, sizeof(pty));
303 	slash = strrchr(pty, '/');
304 	if (slash == NULL || slash[1] == '\0')
305 		errx(EXIT_FAILURE, "%s: invalid tty", tty);
306 
307 	slash[1] = 'p';
308 	if (strcmp(pty, tty) == 0)
309 		errx(EXIT_FAILURE, "Master and slave tty are the same (%s)", tty);
310 
311 	if ((master = open(pty, O_RDWR, 0)) < 0)
312 		err(EXIT_FAILURE, "%s", pty);
313 
314 	/*
315 	 * Slave TTY
316 	 */
317 
318 	if ((gr = getgrnam("tty")) != NULL)
319 		ttygid = gr->gr_gid;
320 	else
321 		ttygid = (gid_t)-1;
322 
323 	(void)chown(tty, getuid(), ttygid);
324 	(void)chmod(tty, S_IRUSR | S_IWUSR | S_IWGRP);
325 	(void)revoke(tty);
326 
327 	return master;
328 }
329 
330 int
331 open_client(bdaddr_t *laddr, bdaddr_t *raddr, int lm, uintmax_t psm, const char *service)
332 {
333 	struct sockaddr_bt sa;
334 	struct service *s;
335 	struct linger l;
336 	char *ep;
337 	int fd, error;
338 	uintmax_t channel;
339 
340 	for (s = services ; ; s++) {
341 		if (s->name == NULL) {
342 			channel = strtoul(service, &ep, 10);
343 			if (*ep != '\0')
344 				errx(EXIT_FAILURE, "Unknown service: %s", service);
345 
346 			break;
347 		}
348 
349 		if (strcasecmp(s->name, service) == 0) {
350 			error = service_search(laddr, raddr, s->class, &psm, &channel);
351 			if (error != 0)
352 				errx(EXIT_FAILURE, "%s: %s", s->name, strerror(error));
353 
354 			break;
355 		}
356 	}
357 
358 	if (channel < RFCOMM_CHANNEL_MIN || channel > RFCOMM_CHANNEL_MAX)
359 		errx(EXIT_FAILURE, "Invalid channel %"PRIuMAX, channel);
360 
361 	if (L2CAP_PSM_INVALID(psm))
362 		errx(EXIT_FAILURE, "Invalid PSM 0x%04"PRIxMAX, psm);
363 
364 	memset(&sa, 0, sizeof(sa));
365 	sa.bt_len = sizeof(sa);
366 	sa.bt_family = AF_BLUETOOTH;
367 	bdaddr_copy(&sa.bt_bdaddr, laddr);
368 
369 	fd = socket(PF_BLUETOOTH, SOCK_STREAM, BTPROTO_RFCOMM);
370 	if (fd < 0)
371 		err(EXIT_FAILURE, "socket()");
372 
373 	if (bind(fd, (struct sockaddr *)&sa, sizeof(sa)) < 0)
374 		err(EXIT_FAILURE, "bind(%s)", bt_ntoa(laddr, NULL));
375 
376 	memset(&l, 0, sizeof(l));
377 	l.l_onoff = 1;
378 	l.l_linger = 5;
379 	if (setsockopt(fd, SOL_SOCKET, SO_LINGER, &l, sizeof(l)) < 0)
380 		err(EXIT_FAILURE, "linger()");
381 
382 	if (setsockopt(fd, BTPROTO_RFCOMM, SO_RFCOMM_LM, &lm, sizeof(lm)) < 0)
383 		err(EXIT_FAILURE, "link mode");
384 
385 	sa.bt_psm = psm;
386 	sa.bt_channel = channel;
387 	bdaddr_copy(&sa.bt_bdaddr, raddr);
388 
389 	if (connect(fd, (struct sockaddr *)&sa, sizeof(sa)) < 0)
390 		err(EXIT_FAILURE, "connect(%s, 0x%04"PRIxMAX", %"PRIuMAX")",
391 		    bt_ntoa(raddr, NULL), psm, channel);
392 
393 	return fd;
394 }
395 
396 int
397 open_server(bdaddr_t *laddr, uint16_t psm, uint8_t channel, int lm, const char *service)
398 {
399 	uint8_t	buffer[256];
400 	struct sockaddr_bt sa;
401 	struct service *s;
402 	struct linger l;
403 	socklen_t len;
404 	sdp_session_t ss;
405 	sdp_data_t rec;
406 	int sv, fd;
407 
408 	for (s = services; ; s++) {
409 		if (s->name == NULL)
410 			usage();
411 
412 		if (strcasecmp(s->name, service) == 0)
413 			break;
414 	}
415 
416 	/* Open server socket */
417 	sv = socket(PF_BLUETOOTH, SOCK_STREAM, BTPROTO_RFCOMM);
418 	if (sv < 0)
419 		err(EXIT_FAILURE, "socket()");
420 
421 	memset(&sa, 0, sizeof(sa));
422 	sa.bt_len = sizeof(sa);
423 	sa.bt_family = AF_BLUETOOTH;
424 	sa.bt_psm = psm;
425 	sa.bt_channel = channel;
426 	bdaddr_copy(&sa.bt_bdaddr, laddr);
427 	if (bind(sv, (struct sockaddr *)&sa, sizeof(sa)) < 0)
428 		err(EXIT_FAILURE, "bind(%s, 0x%04x, %d)",
429 		    bt_ntoa(laddr, NULL), psm, channel);
430 
431 	if (setsockopt(sv, BTPROTO_RFCOMM, SO_RFCOMM_LM, &lm, sizeof(lm)) < 0)
432 		err(EXIT_FAILURE, "link mode");
433 
434 	if (listen(sv, 1) < 0)
435 		err(EXIT_FAILURE, "listen()");
436 
437 	len = sizeof(sa);
438 	if (getsockname(sv, (struct sockaddr *)&sa, &len) < 0)
439 		err(EXIT_FAILURE, "getsockname()");
440 	if (len != sizeof(sa))
441 		errx(EXIT_FAILURE, "getsockname()");
442 
443 	/* Build SDP record */
444 	rec.next = buffer;
445 	rec.end = buffer + sizeof(buffer);
446 
447 	sdp_put_uint16(&rec, SDP_ATTR_SERVICE_RECORD_HANDLE);
448 	sdp_put_uint32(&rec, 0x00000000);
449 
450 	sdp_put_uint16(&rec, SDP_ATTR_SERVICE_CLASS_ID_LIST);
451 	sdp_put_seq(&rec, 3);
452 	sdp_put_uuid16(&rec, s->class);
453 
454 	len = (psm == L2CAP_PSM_RFCOMM ? 0 : 3);
455 
456 	sdp_put_uint16(&rec, SDP_ATTR_PROTOCOL_DESCRIPTOR_LIST);
457 	sdp_put_seq(&rec, 12 + len);
458 	sdp_put_seq(&rec, 3 + len);
459 	sdp_put_uuid16(&rec, SDP_UUID_PROTOCOL_L2CAP);
460 	if (len > 0)
461 		sdp_put_uint16(&rec, psm);
462 	sdp_put_seq(&rec, 5);
463 	sdp_put_uuid16(&rec, SDP_UUID_PROTOCOL_RFCOMM);
464 	sdp_put_uint8(&rec, sa.bt_channel);
465 
466 	sdp_put_uint16(&rec, SDP_ATTR_BROWSE_GROUP_LIST);
467 	sdp_put_seq(&rec, 3);
468 	sdp_put_uuid16(&rec, SDP_SERVICE_CLASS_PUBLIC_BROWSE_GROUP);
469 
470 	sdp_put_uint16(&rec, SDP_ATTR_LANGUAGE_BASE_ATTRIBUTE_ID_LIST);
471 	sdp_put_seq(&rec, 9);
472 	sdp_put_uint16(&rec, 0x656e);	/* "en" */
473 	sdp_put_uint16(&rec, 106);	/* UTF-8 */
474 	sdp_put_uint16(&rec, SDP_ATTR_PRIMARY_LANGUAGE_BASE_ID);
475 
476 	if (s->class == SDP_SERVICE_CLASS_LAN_ACCESS_USING_PPP) {
477 		sdp_put_uint16(&rec, SDP_ATTR_SERVICE_AVAILABILITY);
478 		sdp_put_uint8(&rec, 0x00);
479 	}
480 
481 	sdp_put_uint16(&rec, SDP_ATTR_BLUETOOTH_PROFILE_DESCRIPTOR_LIST);
482 	sdp_put_seq(&rec, 8);
483 	sdp_put_seq(&rec, 6);
484 	sdp_put_uuid16(&rec, s->class);
485 	sdp_put_uint16(&rec, 0x0100);	/* v1.0 */
486 
487 	sdp_put_uint16(&rec, SDP_ATTR_PRIMARY_LANGUAGE_BASE_ID
488 	    + SDP_ATTR_SERVICE_NAME_OFFSET);
489 	sdp_put_str(&rec, s->description, -1);
490 
491 	if (s->class == SDP_SERVICE_CLASS_DIALUP_NETWORKING) {
492 		sdp_put_uint16(&rec, SDP_ATTR_AUDIO_FEEDBACK_SUPPORT);
493 		sdp_put_bool(&rec, false);
494 	}
495 
496 #if 0
497 	if (s->class == SDP_SERVICE_CLASS_LAN_ACCESS_USING_PPP) {
498 		sdp_put_uint16(&rec, SDP_ATTR_IP_SUBNET);	/* TODO */
499 		sdp_put_str(&rec, "0.0.0.0/0", -1);
500 	}
501 #endif
502 
503 	rec.end = rec.next;
504 	rec.next = buffer;
505 
506 	/* Register service with SDP server */
507 	ss = sdp_open_local(NULL);
508 	if (ss == NULL)
509 		err(EXIT_FAILURE, "sdp_open_local");
510 
511 	if (!sdp_record_insert(ss, laddr, NULL, &rec))
512 		err(EXIT_FAILURE, "sdp_record_insert");
513 
514 	/* Accept client connection */
515 	len = sizeof(sa);
516 	fd = accept(sv, (struct sockaddr *)&sa, &len);
517 	if (fd < 0)
518 		err(EXIT_FAILURE, "accept");
519 
520 	memset(&l, 0, sizeof(l));
521 	l.l_onoff = 1;
522 	l.l_linger = 5;
523 	if (setsockopt(fd, SOL_SOCKET, SO_LINGER, &l, sizeof(l)) < 0)
524 		err(EXIT_FAILURE, "linger()");
525 
526 	close(sv);
527 	return fd;
528 }
529 
530 void
531 copy_data(int src, int dst)
532 {
533 	static char	buf[BUFSIZ];
534 	ssize_t		nr, nw, off;
535 
536 	while ((nr = read(src, buf, sizeof(buf))) == -1) {
537 		if (errno != EINTR) {
538 			syslog(LOG_ERR, "read failed: %m");
539 			exit(EXIT_FAILURE);
540 		}
541 	}
542 
543 	if (nr == 0)	/* reached EOF */
544 		done++;
545 
546 	for (off = 0 ; nr ; nr -= nw, off += nw) {
547 		if ((nw = write(dst, buf + off, (size_t)nr)) == -1) {
548 			syslog(LOG_ERR, "write failed: %m");
549 			exit(EXIT_FAILURE);
550 		}
551 	}
552 }
553 
554 int
555 service_search(bdaddr_t const *laddr, bdaddr_t const *raddr,
556     uint16_t class, uintmax_t *psm, uintmax_t *channel)
557 {
558 	uint8_t		buffer[6];	/* SSP (3 bytes) + AIL (3 bytes) */
559 	sdp_session_t	ss;
560 	sdp_data_t	ail, ssp, rsp, rec, value, pdl, seq;
561 	uint16_t	attr;
562 	bool		rv;
563 
564 	seq.next = buffer;
565 	seq.end = buffer + sizeof(buffer);
566 
567 	/*
568 	 * build ServiceSearchPattern (3 bytes)
569 	 */
570 	ssp.next = seq.next;
571 	sdp_put_uuid16(&seq, class);
572 	ssp.end = seq.next;
573 
574 	/*
575 	 * build AttributeIDList (3 bytes)
576 	 */
577 	ail.next = seq.next;
578 	sdp_put_uint16(&seq, SDP_ATTR_PROTOCOL_DESCRIPTOR_LIST);
579 	ail.end = seq.next;
580 
581 	ss = sdp_open(laddr, raddr);
582 	if (ss == NULL)
583 		return errno;
584 
585 	rv = sdp_service_search_attribute(ss, &ssp, &ail, &rsp);
586 	if (!rv) {
587 		sdp_close(ss);
588 		return errno;
589 	}
590 
591 	/*
592 	 * The response will be a list of records that matched our
593 	 * ServiceSearchPattern, where each record is a sequence
594 	 * containing a single ProtocolDescriptorList attribute and
595 	 * value
596 	 *
597 	 *	seq
598 	 *	  uint16	ProtocolDescriptorList
599 	 *	  value
600 	 *	seq
601 	 *	  uint16	ProtocolDescriptorList
602 	 *	  value
603 	 *
604 	 * If the ProtocolDescriptorList describes a single stack,
605 	 * the attribute value takes the form of a single Data Element
606 	 * Sequence where each member is a protocol descriptor.
607 	 *
608 	 *	seq
609 	 *	  list
610 	 *
611 	 * If it is possible for more than one kind of protocol
612 	 * stack to be used to gain access to the service, the
613 	 * ProtocolDescriptorList takes the form of a Data Element
614 	 * Alternative where each member is a Data Element Sequence
615 	 * describing an alternative protocol stack.
616 	 *
617 	 *	alt
618 	 *	  seq
619 	 *	    list
620 	 *	  seq
621 	 *	    list
622 	 *
623 	 * Each protocol stack description contains a sequence for each
624 	 * protocol, where each sequence contains the protocol UUID as
625 	 * the first element, and any ProtocolSpecificParameters. We are
626 	 * interested in the L2CAP psm if provided, and the RFCOMM channel
627 	 * number, stored as parameter#1 in each case.
628 	 *
629 	 *	seq
630 	 *	  uuid		L2CAP
631 	 *	  uint16	psm
632 	 *	seq
633 	 *	  uuid		RFCOMM
634 	 *	  uint8		channel
635 	 */
636 
637 	rv = false;
638 	while (!rv && sdp_get_seq(&rsp, &rec)) {
639 		if (!sdp_get_attr(&rec, &attr, &value)
640 		    || attr != SDP_ATTR_PROTOCOL_DESCRIPTOR_LIST)
641 			continue;
642 
643 		sdp_get_alt(&value, &value);	/* strip any alt container */
644 		while (!rv && sdp_get_seq(&value, &pdl)) {
645 			*psm = L2CAP_PSM_RFCOMM;
646 			if (sdp_get_seq(&pdl, &seq)
647 			    && sdp_match_uuid16(&seq, SDP_UUID_PROTOCOL_L2CAP)
648 			    && (sdp_get_uint(&seq, psm) || true)
649 			    && sdp_get_seq(&pdl, &seq)
650 			    && sdp_match_uuid16(&seq, SDP_UUID_PROTOCOL_RFCOMM)
651 			    && sdp_get_uint(&seq, channel))
652 				rv = true;
653 		}
654 	}
655 
656 	sdp_close(ss);
657 	return (rv) ? 0 : ENOATTR;
658 }
659 
660 void
661 sighandler(int s)
662 {
663 
664 	done++;
665 }
666 
667 void
668 reset_tio(void)
669 {
670 
671 	tcsetattr(STDIN_FILENO, TCSAFLUSH, &tio);
672 }
673 
674 void
675 usage(void)
676 {
677 	const char *cmd = getprogname();
678 	struct service *s;
679 
680 	fprintf(stderr, "Usage: %s [-d device] [-m mode] [-p psm] [-s service] [-t tty]\n"
681 			"       %*s {-a bdaddr | [-c channel]}\n"
682 			"\n"
683 			"Where:\n"
684 			"\t-a bdaddr    remote device address\n"
685 			"\t-c channel   local RFCOMM channel\n"
686 			"\t-d device    local device address\n"
687 			"\t-m mode      link mode\n"
688 			"\t-p psm       protocol/service multiplexer\n"
689 			"\t-s service   service class\n"
690 			"\t-t tty       run in background using pty\n"
691 			"\n", cmd, (int)strlen(cmd), "");
692 
693 	fprintf(stderr, "Known service classes:\n");
694 	for (s = services ; s->name != NULL ; s++)
695 		fprintf(stderr, "\t%-13s%s\n", s->name, s->description);
696 
697 	exit(EXIT_FAILURE);
698 }
699