1 /*
2  * rfcomm_pppd.c
3  */
4 
5 /*-
6  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
7  *
8  * Copyright (c) 2001-2008 Maksim Yevmenkin <m_evmenkin@yahoo.com>
9  * All rights reserved.
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  *
20  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  *
32  * $Id: rfcomm_pppd.c,v 1.5 2003/09/07 18:32:11 max Exp $
33  * $FreeBSD$
34  */
35 #define L2CAP_SOCKET_CHECKED
36 #include <bluetooth.h>
37 #include <ctype.h>
38 #include <err.h>
39 #include <errno.h>
40 #include <fcntl.h>
41 #include <sdp.h>
42 #include <signal.h>
43 #include <stdarg.h>
44 #include <stdio.h>
45 #include <stdlib.h>
46 #include <string.h>
47 #include <syslog.h>
48 #include <unistd.h>
49 
50 #define RFCOMM_PPPD	"rfcomm_pppd"
51 
52 int		rfcomm_channel_lookup	(bdaddr_t const *local,
53 					 bdaddr_t const *remote,
54 					 int service, int *channel, int *error);
55 
56 static void	exec_ppp	(int s, char *unit, char *label);
57 static void	sighandler	(int s);
58 static void	usage		(void);
59 
60 static int	done;
61 
62 /* Main */
63 int
64 main(int argc, char *argv[])
65 {
66 	struct sockaddr_rfcomm   sock_addr;
67 	char			*label = NULL, *unit = NULL, *ep = NULL;
68 	bdaddr_t		 addr;
69 	int			 s, channel, detach, server, service,
70 				 regdun, regsp;
71 	pid_t			 pid;
72 
73 	memcpy(&addr, NG_HCI_BDADDR_ANY, sizeof(addr));
74 	channel = 0;
75 	detach = 1;
76 	server = 0;
77 	service = 0;
78 	regdun = 0;
79 	regsp = 0;
80 
81 	/* Parse command line arguments */
82 	while ((s = getopt(argc, argv, "a:cC:dDhl:sSu:")) != -1) {
83 		switch (s) {
84 		case 'a': /* BDADDR */
85 			if (!bt_aton(optarg, &addr)) {
86 				struct hostent	*he = NULL;
87 
88 				if ((he = bt_gethostbyname(optarg)) == NULL)
89 					errx(1, "%s: %s", optarg, hstrerror(h_errno));
90 
91 				memcpy(&addr, he->h_addr, sizeof(addr));
92 			}
93 			break;
94 
95 		case 'c': /* client */
96 			server = 0;
97 			break;
98 
99 		case 'C': /* RFCOMM channel */
100 			channel = strtoul(optarg, &ep, 10);
101 			if (*ep != '\0') {
102 				channel = 0;
103 				switch (tolower(optarg[0])) {
104 				case 'd': /* DialUp Networking */
105 					service = SDP_SERVICE_CLASS_DIALUP_NETWORKING;
106 					break;
107 
108 				case 'l': /* LAN Access Using PPP */
109 					service = SDP_SERVICE_CLASS_LAN_ACCESS_USING_PPP;
110 					break;
111 				}
112 			}
113 			break;
114 
115 		case 'd': /* do not detach */
116 			detach = 0;
117 			break;
118 
119 		case 'D': /* Register DUN service as well as LAN service */
120 			regdun = 1;
121 			break;
122 
123 		case 'l': /* PPP label */
124 			label = optarg;
125 			break;
126 
127 		case 's': /* server */
128 			server = 1;
129 			break;
130 
131 		case 'S': /* Register SP service as well as LAN service */
132 			regsp = 1;
133 			break;
134 
135 		case 'u': /* PPP -unit option */
136 			strtoul(optarg, &ep, 10);
137 			if (*ep != '\0')
138 				usage();
139 				/* NOT REACHED */
140 
141 			unit = optarg;
142 			break;
143 
144 		case 'h':
145 		default:
146 			usage();
147 			/* NOT REACHED */
148 		}
149 	}
150 
151 	/* Check if we got everything we wanted */
152 	if (label == NULL)
153                 errx(1, "Must specify PPP label");
154 
155 	if (!server) {
156 		if (memcmp(&addr, NG_HCI_BDADDR_ANY, sizeof(addr)) == 0)
157                 	errx(1, "Must specify server BD_ADDR");
158 
159 		/* Check channel, if was not set then obtain it via SDP */
160 		if (channel == 0 && service != 0)
161 			if (rfcomm_channel_lookup(NULL, &addr, service,
162 							&channel, &s) != 0)
163 				errc(1, s, "Could not obtain RFCOMM channel");
164 	}
165 
166         if (channel <= 0 || channel > 30)
167                 errx(1, "Invalid RFCOMM channel number %d", channel);
168 
169 	openlog(RFCOMM_PPPD, LOG_PID | LOG_PERROR | LOG_NDELAY, LOG_USER);
170 
171 	if (detach && daemon(0, 0) < 0) {
172 		syslog(LOG_ERR, "Could not daemon(0, 0). %s (%d)",
173 			strerror(errno), errno);
174 		exit(1);
175 	}
176 
177 	s = socket(PF_BLUETOOTH, SOCK_STREAM, BLUETOOTH_PROTO_RFCOMM);
178 	if (s < 0) {
179 		syslog(LOG_ERR, "Could not create socket. %s (%d)",
180 			strerror(errno), errno);
181 		exit(1);
182 	}
183 
184 	if (server) {
185 		struct sigaction	 sa;
186 		void			*ss = NULL;
187 		sdp_lan_profile_t	 lan;
188 
189 		/* Install signal handler */
190 		memset(&sa, 0, sizeof(sa));
191 		sa.sa_handler = sighandler;
192 
193 		if (sigaction(SIGTERM, &sa, NULL) < 0) {
194 			syslog(LOG_ERR, "Could not sigaction(SIGTERM). %s (%d)",
195 				strerror(errno), errno);
196 			exit(1);
197 		}
198 
199 		if (sigaction(SIGHUP, &sa, NULL) < 0) {
200 			syslog(LOG_ERR, "Could not sigaction(SIGHUP). %s (%d)",
201 				strerror(errno), errno);
202 			exit(1);
203 		}
204 
205 		if (sigaction(SIGINT, &sa, NULL) < 0) {
206 			syslog(LOG_ERR, "Could not sigaction(SIGINT). %s (%d)",
207 				strerror(errno), errno);
208 			exit(1);
209 		}
210 
211 		sa.sa_handler = SIG_IGN;
212 		sa.sa_flags = SA_NOCLDWAIT;
213 
214 		if (sigaction(SIGCHLD, &sa, NULL) < 0) {
215 			syslog(LOG_ERR, "Could not sigaction(SIGCHLD). %s (%d)",
216 				strerror(errno), errno);
217 			exit(1);
218 		}
219 
220 		/* bind socket and listen for incoming connections */
221 		sock_addr.rfcomm_len = sizeof(sock_addr);
222 		sock_addr.rfcomm_family = AF_BLUETOOTH;
223 		memcpy(&sock_addr.rfcomm_bdaddr, &addr,
224 			sizeof(sock_addr.rfcomm_bdaddr));
225 		sock_addr.rfcomm_channel = channel;
226 
227 		if (bind(s, (struct sockaddr *) &sock_addr,
228 				sizeof(sock_addr)) < 0) {
229 			syslog(LOG_ERR, "Could not bind socket. %s (%d)",
230 				strerror(errno), errno);
231 			exit(1);
232 		}
233 
234 		if (listen(s, 10) < 0) {
235 			syslog(LOG_ERR, "Could not listen on socket. %s (%d)",
236 				strerror(errno), errno);
237 			exit(1);
238 		}
239 
240 		ss = sdp_open_local(NULL);
241 		if (ss == NULL) {
242 			syslog(LOG_ERR, "Unable to create local SDP session");
243 			exit(1);
244 		}
245 
246 		if (sdp_error(ss) != 0) {
247 			syslog(LOG_ERR, "Unable to open local SDP session. " \
248 				"%s (%d)", strerror(sdp_error(ss)),
249 				sdp_error(ss));
250 			exit(1);
251 		}
252 
253 		memset(&lan, 0, sizeof(lan));
254 		lan.server_channel = channel;
255 
256 		if (sdp_register_service(ss,
257 				SDP_SERVICE_CLASS_LAN_ACCESS_USING_PPP,
258 				&addr, (void *) &lan, sizeof(lan), NULL) != 0) {
259 			syslog(LOG_ERR, "Unable to register LAN service with " \
260 				"local SDP daemon. %s (%d)",
261 				strerror(sdp_error(ss)), sdp_error(ss));
262 			exit(1);
263 		}
264 
265 		/*
266 		 * Register DUN (Dial-Up Networking) service on the same
267 		 * RFCOMM channel if requested. There is really no good reason
268 		 * to not to support this. AT-command exchange can be faked
269 		 * with chat script in ppp.conf
270 		 */
271 
272 		if (regdun) {
273 			sdp_dun_profile_t	dun;
274 
275 			memset(&dun, 0, sizeof(dun));
276 			dun.server_channel = channel;
277 
278 			if (sdp_register_service(ss,
279 					SDP_SERVICE_CLASS_DIALUP_NETWORKING,
280 					&addr, (void *) &dun, sizeof(dun),
281 					NULL) != 0) {
282 				syslog(LOG_ERR, "Unable to register DUN " \
283 					"service with local SDP daemon. " \
284 					"%s (%d)", strerror(sdp_error(ss)),
285 					sdp_error(ss));
286 				exit(1);
287 			}
288 		}
289 
290 		/*
291 		 * Register SP (Serial Port) service on the same RFCOMM channel
292 		 * if requested. It appears that some cell phones are using so
293 		 * called "callback mechanism". In this scenario user is trying
294 		 * to connect his cell phone to the Internet, and, user's host
295 		 * computer is acting as the gateway server. It seems that it
296 		 * is not possible to tell the phone to just connect and start
297 		 * using the LAN service. Instead the user's host computer must
298 		 * "jump start" the phone by connecting to the phone's SP
299 		 * service. What happens next is the phone kills the existing
300 		 * connection and opens another connection back to the user's
301 		 * host computer. The phone really wants to use LAN service,
302 		 * but for whatever reason it looks for SP service on the
303 		 * user's host computer. This brain damaged behavior was
304 		 * reported for Nokia 6600 and Sony/Ericsson P900. Both phones
305 		 * are Symbian-based phones. Perhaps this is a Symbian problem?
306 		 */
307 
308 		if (regsp) {
309 			sdp_sp_profile_t	sp;
310 
311 			memset(&sp, 0, sizeof(sp));
312 			sp.server_channel = channel;
313 
314 			if (sdp_register_service(ss,
315 					SDP_SERVICE_CLASS_SERIAL_PORT,
316 					&addr, (void *) &sp, sizeof(sp),
317 					NULL) != 0) {
318 				syslog(LOG_ERR, "Unable to register SP " \
319 					"service with local SDP daemon. " \
320 					"%s (%d)", strerror(sdp_error(ss)),
321 					sdp_error(ss));
322 				exit(1);
323 			}
324 		}
325 
326 		for (done = 0; !done; ) {
327 			socklen_t	len = sizeof(sock_addr);
328 			int		s1 = accept(s, (struct sockaddr *) &sock_addr, &len);
329 
330 			if (s1 < 0) {
331 				syslog(LOG_ERR, "Could not accept connection " \
332 					"on socket. %s (%d)", strerror(errno),
333 					errno);
334 				exit(1);
335 			}
336 
337 			pid = fork();
338 			if (pid == (pid_t) -1) {
339 				syslog(LOG_ERR, "Could not fork(). %s (%d)",
340 					strerror(errno), errno);
341 				exit(1);
342 			}
343 
344 			if (pid == 0) {
345 				sdp_close(ss);
346 				close(s);
347 
348 				/* Reset signal handler */
349 				memset(&sa, 0, sizeof(sa));
350 				sa.sa_handler = SIG_DFL;
351 
352 				sigaction(SIGTERM, &sa, NULL);
353 				sigaction(SIGHUP, &sa, NULL);
354 				sigaction(SIGINT, &sa, NULL);
355 				sigaction(SIGCHLD, &sa, NULL);
356 
357 				/* Become daemon */
358 				daemon(0, 0);
359 
360 				/*
361 				 * XXX Make sure user does not shoot himself
362 				 * in the foot. Do not pass unit option to the
363 				 * PPP when operating in the server mode.
364 				 */
365 
366 				exec_ppp(s1, NULL, label);
367 			} else
368 				close(s1);
369 		}
370 	} else {
371 		sock_addr.rfcomm_len = sizeof(sock_addr);
372 		sock_addr.rfcomm_family = AF_BLUETOOTH;
373 		memcpy(&sock_addr.rfcomm_bdaddr, NG_HCI_BDADDR_ANY,
374 			sizeof(sock_addr.rfcomm_bdaddr));
375 		sock_addr.rfcomm_channel = 0;
376 
377 		if (bind(s, (struct sockaddr *) &sock_addr,
378 				sizeof(sock_addr)) < 0) {
379 			syslog(LOG_ERR, "Could not bind socket. %s (%d)",
380 				strerror(errno), errno);
381 			exit(1);
382 		}
383 
384 		memcpy(&sock_addr.rfcomm_bdaddr, &addr,
385 			sizeof(sock_addr.rfcomm_bdaddr));
386 		sock_addr.rfcomm_channel = channel;
387 
388 		if (connect(s, (struct sockaddr *) &sock_addr,
389 				sizeof(sock_addr)) < 0) {
390 			syslog(LOG_ERR, "Could not connect socket. %s (%d)",
391 				strerror(errno), errno);
392 			exit(1);
393 		}
394 
395 		exec_ppp(s, unit, label);
396 	}
397 
398 	exit(0);
399 } /* main */
400 
401 /*
402  * Redirects stdin/stdout to s, stderr to /dev/null and exec
403  * 'ppp -direct -quiet [-unit N] label'. Never returns.
404  */
405 
406 static void
407 exec_ppp(int s, char *unit, char *label)
408 {
409 	char	 ppp[] = "/usr/sbin/ppp";
410 	char	*ppp_args[] = { ppp,  "-direct", "-quiet",
411 				NULL, NULL,      NULL,     NULL };
412 
413 	close(0);
414 	if (dup(s) < 0) {
415 		syslog(LOG_ERR, "Could not dup(0). %s (%d)",
416 			strerror(errno), errno);
417 		exit(1);
418 	}
419 
420 	close(1);
421 	if (dup(s) < 0) {
422 		syslog(LOG_ERR, "Could not dup(1). %s (%d)",
423 			strerror(errno), errno);
424 		exit(1);
425 	}
426 
427 	close(2);
428 	open("/dev/null", O_RDWR);
429 
430 	if (unit != NULL) {
431 		ppp_args[3] = "-unit";
432 		ppp_args[4] = unit;
433 		ppp_args[5] = label;
434 	} else
435 		ppp_args[3] = label;
436 
437 	if (execv(ppp, ppp_args) < 0) {
438 		syslog(LOG_ERR, "Could not exec(%s -direct -quiet%s%s %s). " \
439 			"%s (%d)", ppp, (unit != NULL)? " -unit " : "",
440 			(unit != NULL)? unit : "", label,
441 			strerror(errno), errno);
442 		exit(1);
443 	}
444 } /* run_ppp */
445 
446 /* Signal handler */
447 static void
448 sighandler(int s)
449 {
450 	done = 1;
451 } /* sighandler */
452 
453 /* Display usage and exit */
454 static void
455 usage(void)
456 {
457 	fprintf(stdout,
458 "Usage: %s options\n" \
459 "Where options are:\n" \
460 "\t-a address   Address to listen on or connect to (required for client)\n" \
461 "\t-c           Act as a clinet (default)\n" \
462 "\t-C channel   RFCOMM channel to listen on or connect to (required)\n" \
463 "\t-d           Run in foreground\n" \
464 "\t-D           Register Dial-Up Networking service (server mode only)\n" \
465 "\t-l label     Use PPP label (required)\n" \
466 "\t-s           Act as a server\n" \
467 "\t-S           Register Serial Port service (server mode only)\n" \
468 "\t-u N         Tell PPP to operate on /dev/tunN (client mode only)\n" \
469 "\t-h           Display this message\n", RFCOMM_PPPD);
470 
471 	exit(255);
472 } /* usage */
473 
474