1 /*
2  * rfcomm_pppd.c
3  */
4 
5 /*-
6  * Copyright (c) 2001-2008 Maksim Yevmenkin <m_evmenkin@yahoo.com>
7  * All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28  * SUCH DAMAGE.
29  *
30  * $Id: rfcomm_pppd.c,v 1.5 2003/09/07 18:32:11 max Exp $
31  * $FreeBSD$
32  */
33 #define L2CAP_SOCKET_CHECKED
34 #include <bluetooth.h>
35 #include <ctype.h>
36 #include <err.h>
37 #include <errno.h>
38 #include <fcntl.h>
39 #include <sdp.h>
40 #include <signal.h>
41 #include <stdarg.h>
42 #include <stdio.h>
43 #include <stdlib.h>
44 #include <string.h>
45 #include <syslog.h>
46 #include <unistd.h>
47 
48 #define RFCOMM_PPPD	"rfcomm_pppd"
49 
50 int		rfcomm_channel_lookup	(bdaddr_t const *local,
51 					 bdaddr_t const *remote,
52 					 int service, int *channel, int *error);
53 
54 static void	exec_ppp	(int s, char *unit, char *label);
55 static void	sighandler	(int s);
56 static void	usage		(void);
57 
58 static int	done;
59 
60 /* Main */
61 int
62 main(int argc, char *argv[])
63 {
64 	struct sockaddr_rfcomm   sock_addr;
65 	char			*label = NULL, *unit = NULL, *ep = NULL;
66 	bdaddr_t		 addr;
67 	int			 s, channel, detach, server, service,
68 				 regdun, regsp;
69 	pid_t			 pid;
70 
71 	memcpy(&addr, NG_HCI_BDADDR_ANY, sizeof(addr));
72 	channel = 0;
73 	detach = 1;
74 	server = 0;
75 	service = 0;
76 	regdun = 0;
77 	regsp = 0;
78 
79 	/* Parse command line arguments */
80 	while ((s = getopt(argc, argv, "a:cC:dDhl:sSu:")) != -1) {
81 		switch (s) {
82 		case 'a': /* BDADDR */
83 			if (!bt_aton(optarg, &addr)) {
84 				struct hostent	*he = NULL;
85 
86 				if ((he = bt_gethostbyname(optarg)) == NULL)
87 					errx(1, "%s: %s", optarg, hstrerror(h_errno));
88 
89 				memcpy(&addr, he->h_addr, sizeof(addr));
90 			}
91 			break;
92 
93 		case 'c': /* client */
94 			server = 0;
95 			break;
96 
97 		case 'C': /* RFCOMM channel */
98 			channel = strtoul(optarg, &ep, 10);
99 			if (*ep != '\0') {
100 				channel = 0;
101 				switch (tolower(optarg[0])) {
102 				case 'd': /* DialUp Networking */
103 					service = SDP_SERVICE_CLASS_DIALUP_NETWORKING;
104 					break;
105 
106 				case 'l': /* LAN Access Using PPP */
107 					service = SDP_SERVICE_CLASS_LAN_ACCESS_USING_PPP;
108 					break;
109 				}
110 			}
111 			break;
112 
113 		case 'd': /* do not detach */
114 			detach = 0;
115 			break;
116 
117 		case 'D': /* Register DUN service as well as LAN service */
118 			regdun = 1;
119 			break;
120 
121 		case 'l': /* PPP label */
122 			label = optarg;
123 			break;
124 
125 		case 's': /* server */
126 			server = 1;
127 			break;
128 
129 		case 'S': /* Register SP service as well as LAN service */
130 			regsp = 1;
131 			break;
132 
133 		case 'u': /* PPP -unit option */
134 			strtoul(optarg, &ep, 10);
135 			if (*ep != '\0')
136 				usage();
137 				/* NOT REACHED */
138 
139 			unit = optarg;
140 			break;
141 
142 		case 'h':
143 		default:
144 			usage();
145 			/* NOT REACHED */
146 		}
147 	}
148 
149 	/* Check if we got everything we wanted */
150 	if (label == NULL)
151                 errx(1, "Must specify PPP label");
152 
153 	if (!server) {
154 		if (memcmp(&addr, NG_HCI_BDADDR_ANY, sizeof(addr)) == 0)
155                 	errx(1, "Must specify server BD_ADDR");
156 
157 		/* Check channel, if was not set then obtain it via SDP */
158 		if (channel == 0 && service != 0)
159 			if (rfcomm_channel_lookup(NULL, &addr, service,
160 							&channel, &s) != 0)
161 				errc(1, s, "Could not obtain RFCOMM channel");
162 	}
163 
164         if (channel <= 0 || channel > 30)
165                 errx(1, "Invalid RFCOMM channel number %d", channel);
166 
167 	openlog(RFCOMM_PPPD, LOG_PID | LOG_PERROR | LOG_NDELAY, LOG_USER);
168 
169 	if (detach && daemon(0, 0) < 0) {
170 		syslog(LOG_ERR, "Could not daemon(0, 0). %s (%d)",
171 			strerror(errno), errno);
172 		exit(1);
173 	}
174 
175 	s = socket(PF_BLUETOOTH, SOCK_STREAM, BLUETOOTH_PROTO_RFCOMM);
176 	if (s < 0) {
177 		syslog(LOG_ERR, "Could not create socket. %s (%d)",
178 			strerror(errno), errno);
179 		exit(1);
180 	}
181 
182 	if (server) {
183 		struct sigaction	 sa;
184 		void			*ss = NULL;
185 		sdp_lan_profile_t	 lan;
186 
187 		/* Install signal handler */
188 		memset(&sa, 0, sizeof(sa));
189 		sa.sa_handler = sighandler;
190 
191 		if (sigaction(SIGTERM, &sa, NULL) < 0) {
192 			syslog(LOG_ERR, "Could not sigaction(SIGTERM). %s (%d)",
193 				strerror(errno), errno);
194 			exit(1);
195 		}
196 
197 		if (sigaction(SIGHUP, &sa, NULL) < 0) {
198 			syslog(LOG_ERR, "Could not sigaction(SIGHUP). %s (%d)",
199 				strerror(errno), errno);
200 			exit(1);
201 		}
202 
203 		if (sigaction(SIGINT, &sa, NULL) < 0) {
204 			syslog(LOG_ERR, "Could not sigaction(SIGINT). %s (%d)",
205 				strerror(errno), errno);
206 			exit(1);
207 		}
208 
209 		sa.sa_handler = SIG_IGN;
210 		sa.sa_flags = SA_NOCLDWAIT;
211 
212 		if (sigaction(SIGCHLD, &sa, NULL) < 0) {
213 			syslog(LOG_ERR, "Could not sigaction(SIGCHLD). %s (%d)",
214 				strerror(errno), errno);
215 			exit(1);
216 		}
217 
218 		/* bind socket and listen for incoming connections */
219 		sock_addr.rfcomm_len = sizeof(sock_addr);
220 		sock_addr.rfcomm_family = AF_BLUETOOTH;
221 		memcpy(&sock_addr.rfcomm_bdaddr, &addr,
222 			sizeof(sock_addr.rfcomm_bdaddr));
223 		sock_addr.rfcomm_channel = channel;
224 
225 		if (bind(s, (struct sockaddr *) &sock_addr,
226 				sizeof(sock_addr)) < 0) {
227 			syslog(LOG_ERR, "Could not bind socket. %s (%d)",
228 				strerror(errno), errno);
229 			exit(1);
230 		}
231 
232 		if (listen(s, 10) < 0) {
233 			syslog(LOG_ERR, "Could not listen on socket. %s (%d)",
234 				strerror(errno), errno);
235 			exit(1);
236 		}
237 
238 		ss = sdp_open_local(NULL);
239 		if (ss == NULL) {
240 			syslog(LOG_ERR, "Unable to create local SDP session");
241 			exit(1);
242 		}
243 
244 		if (sdp_error(ss) != 0) {
245 			syslog(LOG_ERR, "Unable to open local SDP session. " \
246 				"%s (%d)", strerror(sdp_error(ss)),
247 				sdp_error(ss));
248 			exit(1);
249 		}
250 
251 		memset(&lan, 0, sizeof(lan));
252 		lan.server_channel = channel;
253 
254 		if (sdp_register_service(ss,
255 				SDP_SERVICE_CLASS_LAN_ACCESS_USING_PPP,
256 				&addr, (void *) &lan, sizeof(lan), NULL) != 0) {
257 			syslog(LOG_ERR, "Unable to register LAN service with " \
258 				"local SDP daemon. %s (%d)",
259 				strerror(sdp_error(ss)), sdp_error(ss));
260 			exit(1);
261 		}
262 
263 		/*
264 		 * Register DUN (Dial-Up Networking) service on the same
265 		 * RFCOMM channel if requested. There is really no good reason
266 		 * to not to support this. AT-command exchange can be faked
267 		 * with chat script in ppp.conf
268 		 */
269 
270 		if (regdun) {
271 			sdp_dun_profile_t	dun;
272 
273 			memset(&dun, 0, sizeof(dun));
274 			dun.server_channel = channel;
275 
276 			if (sdp_register_service(ss,
277 					SDP_SERVICE_CLASS_DIALUP_NETWORKING,
278 					&addr, (void *) &dun, sizeof(dun),
279 					NULL) != 0) {
280 				syslog(LOG_ERR, "Unable to register DUN " \
281 					"service with local SDP daemon. " \
282 					"%s (%d)", strerror(sdp_error(ss)),
283 					sdp_error(ss));
284 				exit(1);
285 			}
286 		}
287 
288 		/*
289 		 * Register SP (Serial Port) service on the same RFCOMM channel
290 		 * if requested. It appears that some cell phones are using so
291 		 * called "callback mechanism". In this scenario user is trying
292 		 * to connect his cell phone to the Internet, and, user's host
293 		 * computer is acting as the gateway server. It seems that it
294 		 * is not possible to tell the phone to just connect and start
295 		 * using the LAN service. Instead the user's host computer must
296 		 * "jump start" the phone by connecting to the phone's SP
297 		 * service. What happens next is the phone kills the existing
298 		 * connection and opens another connection back to the user's
299 		 * host computer. The phone really wants to use LAN service,
300 		 * but for whatever reason it looks for SP service on the
301 		 * user's host computer. This brain damaged behavior was
302 		 * reported for Nokia 6600 and Sony/Ericsson P900. Both phones
303 		 * are Symbian-based phones. Perhaps this is a Symbian problem?
304 		 */
305 
306 		if (regsp) {
307 			sdp_sp_profile_t	sp;
308 
309 			memset(&sp, 0, sizeof(sp));
310 			sp.server_channel = channel;
311 
312 			if (sdp_register_service(ss,
313 					SDP_SERVICE_CLASS_SERIAL_PORT,
314 					&addr, (void *) &sp, sizeof(sp),
315 					NULL) != 0) {
316 				syslog(LOG_ERR, "Unable to register SP " \
317 					"service with local SDP daemon. " \
318 					"%s (%d)", strerror(sdp_error(ss)),
319 					sdp_error(ss));
320 				exit(1);
321 			}
322 		}
323 
324 		for (done = 0; !done; ) {
325 			socklen_t	len = sizeof(sock_addr);
326 			int		s1 = accept(s, (struct sockaddr *) &sock_addr, &len);
327 
328 			if (s1 < 0) {
329 				syslog(LOG_ERR, "Could not accept connection " \
330 					"on socket. %s (%d)", strerror(errno),
331 					errno);
332 				exit(1);
333 			}
334 
335 			pid = fork();
336 			if (pid == (pid_t) -1) {
337 				syslog(LOG_ERR, "Could not fork(). %s (%d)",
338 					strerror(errno), errno);
339 				exit(1);
340 			}
341 
342 			if (pid == 0) {
343 				sdp_close(ss);
344 				close(s);
345 
346 				/* Reset signal handler */
347 				memset(&sa, 0, sizeof(sa));
348 				sa.sa_handler = SIG_DFL;
349 
350 				sigaction(SIGTERM, &sa, NULL);
351 				sigaction(SIGHUP, &sa, NULL);
352 				sigaction(SIGINT, &sa, NULL);
353 				sigaction(SIGCHLD, &sa, NULL);
354 
355 				/* Become daemon */
356 				daemon(0, 0);
357 
358 				/*
359 				 * XXX Make sure user does not shoot himself
360 				 * in the foot. Do not pass unit option to the
361 				 * PPP when operating in the server mode.
362 				 */
363 
364 				exec_ppp(s1, NULL, label);
365 			} else
366 				close(s1);
367 		}
368 	} else {
369 		sock_addr.rfcomm_len = sizeof(sock_addr);
370 		sock_addr.rfcomm_family = AF_BLUETOOTH;
371 		memcpy(&sock_addr.rfcomm_bdaddr, NG_HCI_BDADDR_ANY,
372 			sizeof(sock_addr.rfcomm_bdaddr));
373 		sock_addr.rfcomm_channel = 0;
374 
375 		if (bind(s, (struct sockaddr *) &sock_addr,
376 				sizeof(sock_addr)) < 0) {
377 			syslog(LOG_ERR, "Could not bind socket. %s (%d)",
378 				strerror(errno), errno);
379 			exit(1);
380 		}
381 
382 		memcpy(&sock_addr.rfcomm_bdaddr, &addr,
383 			sizeof(sock_addr.rfcomm_bdaddr));
384 		sock_addr.rfcomm_channel = channel;
385 
386 		if (connect(s, (struct sockaddr *) &sock_addr,
387 				sizeof(sock_addr)) < 0) {
388 			syslog(LOG_ERR, "Could not connect socket. %s (%d)",
389 				strerror(errno), errno);
390 			exit(1);
391 		}
392 
393 		exec_ppp(s, unit, label);
394 	}
395 
396 	exit(0);
397 } /* main */
398 
399 /*
400  * Redirects stdin/stdout to s, stderr to /dev/null and exec
401  * 'ppp -direct -quiet [-unit N] label'. Never returns.
402  */
403 
404 static void
405 exec_ppp(int s, char *unit, char *label)
406 {
407 	char	 ppp[] = "/usr/sbin/ppp";
408 	char	*ppp_args[] = { ppp,  "-direct", "-quiet",
409 				NULL, NULL,      NULL,     NULL };
410 
411 	close(0);
412 	if (dup(s) < 0) {
413 		syslog(LOG_ERR, "Could not dup(0). %s (%d)",
414 			strerror(errno), errno);
415 		exit(1);
416 	}
417 
418 	close(1);
419 	if (dup(s) < 0) {
420 		syslog(LOG_ERR, "Could not dup(1). %s (%d)",
421 			strerror(errno), errno);
422 		exit(1);
423 	}
424 
425 	close(2);
426 	open("/dev/null", O_RDWR);
427 
428 	if (unit != NULL) {
429 		ppp_args[3] = "-unit";
430 		ppp_args[4] = unit;
431 		ppp_args[5] = label;
432 	} else
433 		ppp_args[3] = label;
434 
435 	if (execv(ppp, ppp_args) < 0) {
436 		syslog(LOG_ERR, "Could not exec(%s -direct -quiet%s%s %s). " \
437 			"%s (%d)", ppp, (unit != NULL)? " -unit " : "",
438 			(unit != NULL)? unit : "", label,
439 			strerror(errno), errno);
440 		exit(1);
441 	}
442 } /* run_ppp */
443 
444 /* Signal handler */
445 static void
446 sighandler(int s)
447 {
448 	done = 1;
449 } /* sighandler */
450 
451 /* Display usage and exit */
452 static void
453 usage(void)
454 {
455 	fprintf(stdout,
456 "Usage: %s options\n" \
457 "Where options are:\n" \
458 "\t-a address   Address to listen on or connect to (required for client)\n" \
459 "\t-c           Act as a clinet (default)\n" \
460 "\t-C channel   RFCOMM channel to listen on or connect to (required)\n" \
461 "\t-d           Run in foreground\n" \
462 "\t-D           Register Dial-Up Networking service (server mode only)\n" \
463 "\t-l label     Use PPP label (required)\n" \
464 "\t-s           Act as a server\n" \
465 "\t-S           Register Serial Port service (server mode only)\n" \
466 "\t-u N         Tell PPP to operate on /dev/tunN (client mode only)\n" \
467 "\t-h           Display this message\n", RFCOMM_PPPD);
468 
469 	exit(255);
470 } /* usage */
471 
472