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: stable/11/usr.sbin/bluetooth/rfcomm_pppd/rfcomm_pppd.c 330449 2018-03-05 07:26:05Z eadler $
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
52int		rfcomm_channel_lookup	(bdaddr_t const *local,
53					 bdaddr_t const *remote,
54					 int service, int *channel, int *error);
55
56static void	exec_ppp	(int s, char *unit, char *label);
57static void	sighandler	(int s);
58static void	usage		(void);
59
60static int	done;
61
62/* Main */
63int
64main(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
406static void
407exec_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 */
447static void
448sighandler(int s)
449{
450	done = 1;
451} /* sighandler */
452
453/* Display usage and exit */
454static void
455usage(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