main.c revision 1.56 
1/*	$OpenBSD: main.c,v 1.56 2023/03/08 04:43:14 guenther Exp $	*/
2
3/*
4 * main.c - Point-to-Point Protocol main module
5 *
6 * Copyright (c) 1984-2000 Carnegie Mellon University. All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 *
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in
17 *    the documentation and/or other materials provided with the
18 *    distribution.
19 *
20 * 3. The name "Carnegie Mellon University" must not be used to
21 *    endorse or promote products derived from this software without
22 *    prior written permission. For permission or any legal
23 *    details, please contact
24 *      Office of Technology Transfer
25 *      Carnegie Mellon University
26 *      5000 Forbes Avenue
27 *      Pittsburgh, PA  15213-3890
28 *      (412) 268-4387, fax: (412) 268-7395
29 *      tech-transfer@andrew.cmu.edu
30 *
31 * 4. Redistributions of any form whatsoever must retain the following
32 *    acknowledgment:
33 *    "This product includes software developed by Computing Services
34 *     at Carnegie Mellon University (http://www.cmu.edu/computing/)."
35 *
36 * CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO
37 * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
38 * AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE
39 * FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
40 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
41 * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
42 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
43 */
44
45#include <sys/types.h>
46#include <sys/wait.h>
47#include <sys/time.h>
48#include <sys/resource.h>
49#include <sys/stat.h>
50#include <sys/socket.h>
51#include <net/if.h>
52#include <stdio.h>
53#include <ctype.h>
54#include <stdlib.h>
55#include <string.h>
56#include <unistd.h>
57#include <limits.h>
58#include <signal.h>
59#include <errno.h>
60#include <fcntl.h>
61#include <syslog.h>
62#include <netdb.h>
63#include <utmp.h>
64#include <pwd.h>
65
66#include "pppd.h"
67#include "magic.h"
68#include "fsm.h"
69#include "lcp.h"
70#include "ipcp.h"
71#include "upap.h"
72#include "chap.h"
73#include "ccp.h"
74#include "pathnames.h"
75#include "patchlevel.h"
76
77#ifdef CBCP_SUPPORT
78#include "cbcp.h"
79#endif
80
81#if defined(SUNOS4)
82extern char *strerror();
83#endif
84
85#ifdef AT_CHANGE
86#include "atcp.h"
87#endif
88
89/* interface vars */
90char ifname[IFNAMSIZ];		/* Interface name */
91int ifunit;			/* Interface unit number */
92
93char hostname[HOST_NAME_MAX+1];	/* Our hostname */
94static char default_devnam[PATH_MAX];	/* name of default device */
95static pid_t pid;		/* Our pid */
96static uid_t uid;		/* Our real user-id */
97static int conn_running;	/* we have a [dis]connector running */
98static int crashed = 0;
99
100int ttyfd = -1;			/* Serial port file descriptor */
101mode_t tty_mode = -1;		/* Original access permissions to tty */
102int baud_rate;			/* Actual bits/second for serial device */
103int hungup;			/* terminal has been hung up */
104int privileged;			/* we're running as real uid root */
105int need_holdoff;		/* need holdoff period before restarting */
106int detached;			/* have detached from terminal */
107
108int phase;			/* where the link is at */
109int kill_link;
110int open_ccp_flag;
111
112char **script_env;		/* Env. variable values for scripts */
113int s_env_nalloc;		/* # words avail at script_env */
114
115u_char outpacket_buf[PPP_MRU+PPP_HDRLEN]; /* buffer for outgoing packet */
116u_char inpacket_buf[PPP_MRU+PPP_HDRLEN]; /* buffer for incoming packet */
117
118static int n_children;		/* # child processes still running */
119
120static int locked;		/* lock() has succeeded */
121
122char *no_ppp_msg = "Sorry - this system lacks PPP kernel support\n";
123
124/* Prototypes for procedures local to this file. */
125
126static void cleanup(void);
127static void close_tty(void);
128static void get_input(void);
129static void calltimeout(void);
130static struct timeval *timeleft(struct timeval *);
131static void kill_my_pg(int);
132static void hup(int);
133static void term(int);
134static void chld(int);
135static void toggle_debug(int);
136static void open_ccp(int);
137static void bad_signal(int);
138static void holdoff_end(void *);
139static int device_script(char *, int, int);
140static void reap_kids(void);
141static void pr_log(void *, char *, ...);
142
143extern	char	*ttyname(int);
144extern	char	*getlogin(void);
145int main(int, char *[]);
146
147#ifdef ultrix
148#undef	O_NONBLOCK
149#define	O_NONBLOCK	O_NDELAY
150#endif
151
152#ifdef ULTRIX
153#define setlogmask(x)
154#endif
155
156/*
157 * PPP Data Link Layer "protocol" table.
158 * One entry per supported protocol.
159 * The last entry must be NULL.
160 */
161struct protent *protocols[] = {
162    &lcp_protent,
163    &pap_protent,
164    &chap_protent,
165#ifdef CBCP_SUPPORT
166    &cbcp_protent,
167#endif
168    &ipcp_protent,
169    &ccp_protent,
170#ifdef AT_CHANGE
171    &atcp_protent,
172#endif
173    NULL
174};
175
176int
177main(argc, argv)
178    int argc;
179    char *argv[];
180{
181    int i, fdflags;
182    struct sigaction sa;
183    char *p;
184    struct passwd *pw;
185    struct timeval timo;
186    sigset_t mask;
187    struct protent *protp;
188    struct stat statbuf;
189    char numbuf[16];
190
191    phase = PHASE_INITIALIZE;
192    p = ttyname(0);
193    if (p)
194	strlcpy(devnam, p, PATH_MAX);
195    strlcpy(default_devnam, devnam, sizeof default_devnam);
196
197    script_env = NULL;
198
199    /* Initialize syslog facilities */
200#ifdef ULTRIX
201    openlog("pppd", LOG_PID);
202#else
203    openlog("pppd", LOG_PID | LOG_NDELAY, LOG_PPP);
204    setlogmask(LOG_UPTO(LOG_INFO));
205#endif
206
207    if (gethostname(hostname, sizeof hostname) < 0 ) {
208	option_error("Couldn't get hostname: %m");
209	die(1);
210    }
211
212    uid = getuid();
213    privileged = uid == 0;
214    snprintf(numbuf, sizeof numbuf, "%u", uid);
215    script_setenv("UID", numbuf);
216
217    /*
218     * Initialize to the standard option set, then parse, in order,
219     * the system options file, the user's options file,
220     * the tty's options file, and the command line arguments.
221     */
222    for (i = 0; (protp = protocols[i]) != NULL; ++i)
223	(*protp->init)(0);
224
225    if (!options_from_file(_PATH_SYSOPTIONS, !privileged, 0, 1)
226	|| !options_from_user())
227	exit(1);
228    scan_args(argc-1, argv+1);	/* look for tty name on command line */
229    if (!options_for_tty()
230	|| !parse_args(argc-1, argv+1))
231	exit(1);
232
233    /*
234     * Check that we are running as root.
235     */
236    if (geteuid() != 0) {
237	option_error("must be root to run %s, since it is not setuid-root",
238		     argv[0]);
239	die(1);
240    }
241
242    if (!ppp_available()) {
243	option_error(no_ppp_msg);
244	exit(1);
245    }
246
247    /*
248     * Check that the options given are valid and consistent.
249     */
250    sys_check_options();
251    auth_check_options();
252    for (i = 0; (protp = protocols[i]) != NULL; ++i)
253	if (protp->check_options != NULL)
254	    (*protp->check_options)();
255    if (demand && connector == 0) {
256	option_error("connect script required for demand-dialling\n");
257	exit(1);
258    }
259
260    script_setenv("DEVICE", devnam);
261    snprintf(numbuf, sizeof numbuf, "%d", baud_rate);
262    script_setenv("SPEED", numbuf);
263
264    /*
265     * If the user has specified the default device name explicitly,
266     * pretend they hadn't.
267     */
268    if (!default_device && strcmp(devnam, default_devnam) == 0)
269	default_device = 1;
270    if (default_device)
271	nodetach = 1;
272
273    /*
274     * Initialize system-dependent stuff and magic number package.
275     */
276    sys_init();
277    magic_init();
278    if (debug)
279	setlogmask(LOG_UPTO(LOG_DEBUG));
280
281    /*
282     * Detach ourselves from the terminal, if required,
283     * and identify who is running us.
284     */
285    if (nodetach == 0)
286	detach();
287    pid = getpid();
288    p = getlogin();
289    if (p == NULL) {
290	pw = getpwuid(uid);
291	if (pw != NULL && pw->pw_name != NULL)
292	    p = pw->pw_name;
293	else
294	    p = "(unknown)";
295    }
296    syslog(LOG_NOTICE, "pppd %s.%d%s started by %s, uid %u",
297	   VERSION, PATCHLEVEL, IMPLEMENTATION, p, uid);
298
299    /*
300     * Compute mask of all interesting signals and install signal handlers
301     * for each.  Only one signal handler may be active at a time.  Therefore,
302     * all other signals should be masked when any handler is executing.
303     */
304    sigemptyset(&mask);
305    sigaddset(&mask, SIGHUP);
306    sigaddset(&mask, SIGINT);
307    sigaddset(&mask, SIGTERM);
308    sigaddset(&mask, SIGCHLD);
309
310#define SIGNAL(s, handler)	{ \
311	sa.sa_handler = handler; \
312	if (sigaction(s, &sa, NULL) < 0) { \
313	    syslog(LOG_ERR, "Couldn't establish signal handler (%d): %m", s); \
314	    die(1); \
315	} \
316    }
317
318    sa.sa_mask = mask;
319    sa.sa_flags = 0;
320    SIGNAL(SIGHUP, hup);		/* Hangup */
321    SIGNAL(SIGINT, term);		/* Interrupt */
322    SIGNAL(SIGTERM, term);		/* Terminate */
323    SIGNAL(SIGCHLD, chld);
324
325    SIGNAL(SIGUSR1, toggle_debug);	/* Toggle debug flag */
326    SIGNAL(SIGUSR2, open_ccp);		/* Reopen CCP */
327
328    /*
329     * Install a handler for other signals which would otherwise
330     * cause pppd to exit without cleaning up.
331     */
332    SIGNAL(SIGABRT, bad_signal);
333    SIGNAL(SIGALRM, bad_signal);
334    SIGNAL(SIGFPE, bad_signal);
335    SIGNAL(SIGILL, bad_signal);
336    SIGNAL(SIGPIPE, bad_signal);
337    SIGNAL(SIGQUIT, bad_signal);
338#if SIGSEGV_CHECK
339    SIGNAL(SIGSEGV, bad_signal);
340#endif
341#ifdef SIGBUS
342    SIGNAL(SIGBUS, bad_signal);
343#endif
344#ifdef SIGEMT
345    SIGNAL(SIGEMT, bad_signal);
346#endif
347#ifdef SIGPOLL
348    SIGNAL(SIGPOLL, bad_signal);
349#endif
350#ifdef SIGPROF
351    SIGNAL(SIGPROF, bad_signal);
352#endif
353#ifdef SIGSYS
354    SIGNAL(SIGSYS, bad_signal);
355#endif
356#ifdef SIGTRAP
357    SIGNAL(SIGTRAP, bad_signal);
358#endif
359#ifdef SIGVTALRM
360    SIGNAL(SIGVTALRM, bad_signal);
361#endif
362#ifdef SIGXCPU
363    SIGNAL(SIGXCPU, bad_signal);
364#endif
365#ifdef SIGXFSZ
366    SIGNAL(SIGXFSZ, bad_signal);
367#endif
368
369    /*
370     * Apparently we can get a SIGPIPE when we call syslog, if
371     * syslogd has died and been restarted.  Ignoring it seems
372     * be sufficient.
373     */
374    signal(SIGPIPE, SIG_IGN);
375
376    /*
377     * If we're doing dial-on-demand, set up the interface now.
378     */
379    if (demand) {
380	/*
381	 * Open the loopback channel and set it up to be the ppp interface.
382	 */
383	open_ppp_loopback();
384
385	syslog(LOG_INFO, "Using interface ppp%d", ifunit);
386	(void) snprintf(ifname, sizeof ifname, "ppp%d", ifunit);
387	script_setenv("IFNAME", ifname);
388
389	/*
390	 * Configure the interface and mark it up, etc.
391	 */
392	demand_conf();
393    }
394
395    for (;;) {
396
397	need_holdoff = 1;
398
399	if (demand) {
400	    /*
401	     * Don't do anything until we see some activity.
402	     */
403	    phase = PHASE_DORMANT;
404	    kill_link = 0;
405	    demand_unblock();
406	    for (;;) {
407		wait_loop_output(timeleft(&timo));
408		calltimeout();
409		if (kill_link) {
410		    if (!persist)
411			die(0);
412		    kill_link = 0;
413		}
414		if (get_loop_output())
415		    break;
416		reap_kids();
417	    }
418
419	    /*
420	     * Now we want to bring up the link.
421	     */
422	    demand_drop();
423	    syslog(LOG_INFO, "Starting link");
424	}
425
426	/*
427	 * Lock the device if we've been asked to.
428	 */
429	if (lockflag && !default_device) {
430	    if (lock(devnam) < 0)
431		goto fail;
432	    locked = 1;
433	}
434
435	/*
436	 * Open the serial device and set it up to be the ppp interface.
437	 * First we open it in non-blocking mode so we can set the
438	 * various termios flags appropriately.  If we aren't dialling
439	 * out and we want to use the modem lines, we reopen it later
440	 * in order to wait for the carrier detect signal from the modem.
441	 */
442	while ((ttyfd = open(devnam, O_NONBLOCK | O_RDWR)) < 0) {
443	    if (errno != EINTR)
444		syslog(LOG_ERR, "Failed to open %s: %m", devnam);
445	    if (!persist || errno != EINTR)
446		goto fail;
447	}
448	if ((fdflags = fcntl(ttyfd, F_GETFL)) == -1
449	    || fcntl(ttyfd, F_SETFL, fdflags & ~O_NONBLOCK) < 0)
450	    syslog(LOG_WARNING,
451		   "Couldn't reset non-blocking mode on device: %m");
452
453	hungup = 0;
454	kill_link = 0;
455
456	/*
457	 * Do the equivalent of `mesg n' to stop broadcast messages.
458	 */
459	if (fstat(ttyfd, &statbuf) < 0
460	    || fchmod(ttyfd, statbuf.st_mode & ~(S_IWGRP | S_IWOTH)) < 0) {
461	    syslog(LOG_WARNING,
462		   "Couldn't restrict write permissions to %s: %m", devnam);
463	} else
464	    tty_mode = statbuf.st_mode;
465
466	/* run connection script */
467	if (connector && connector[0]) {
468	    MAINDEBUG((LOG_INFO, "Connecting with <%s>", connector));
469
470	    /*
471	     * Set line speed, flow control, etc.
472	     * On most systems we set CLOCAL for now so that we can talk
473	     * to the modem before carrier comes up.  But this has the
474	     * side effect that we might miss it if CD drops before we
475	     * get to clear CLOCAL below.  On systems where we can talk
476	     * successfully to the modem with CLOCAL clear and CD down,
477	     * we can clear CLOCAL at this point.
478	     */
479	    set_up_tty(ttyfd, (modem_chat == 0));
480
481	    /* drop dtr to hang up in case modem is off hook */
482	    if (!default_device && modem) {
483		setdtr(ttyfd, FALSE);
484		sleep(1);
485		setdtr(ttyfd, TRUE);
486	    }
487
488	    if (device_script(connector, ttyfd, ttyfd) < 0) {
489		syslog(LOG_ERR, "Connect script failed");
490		setdtr(ttyfd, FALSE);
491		goto fail;
492	    }
493
494	    syslog(LOG_INFO, "Serial connection established.");
495	    sleep(1);		/* give it time to set up its terminal */
496	}
497
498	set_up_tty(ttyfd, 0);
499
500	/* reopen tty if necessary to wait for carrier */
501	if (connector == NULL && modem) {
502	    while ((i = open(devnam, O_RDWR)) < 0) {
503		if (errno != EINTR)
504		    syslog(LOG_ERR, "Failed to reopen %s: %m", devnam);
505		if (!persist || errno != EINTR || hungup || kill_link)
506		    goto fail;
507	    }
508	    close(i);
509	}
510
511	/* run welcome script, if any */
512	if (welcomer && welcomer[0]) {
513	    if (device_script(welcomer, ttyfd, ttyfd) < 0)
514		syslog(LOG_WARNING, "Welcome script failed");
515	}
516
517	/* set up the serial device as a ppp interface */
518	establish_ppp(ttyfd);
519
520	if (!demand) {
521
522	    syslog(LOG_INFO, "Using interface ppp%d", ifunit);
523	    (void) snprintf(ifname, sizeof ifname, "ppp%d", ifunit);
524	    script_setenv("IFNAME", ifname);
525	}
526
527	/*
528	 * Start opening the connection and wait for
529	 * incoming events (reply, timeout, etc.).
530	 */
531	syslog(LOG_NOTICE, "Connect: %s <--> %s", ifname, devnam);
532	lcp_lowerup(0);
533	lcp_open(0);		/* Start protocol */
534	for (phase = PHASE_ESTABLISH; phase != PHASE_DEAD; ) {
535	    wait_input(timeleft(&timo));
536	    calltimeout();
537	    get_input();
538	    if (kill_link) {
539		lcp_close(0, "User request");
540		kill_link = 0;
541	    }
542	    if (open_ccp_flag) {
543		if (phase == PHASE_NETWORK) {
544		    ccp_fsm[0].flags = OPT_RESTART; /* clears OPT_SILENT */
545		    (*ccp_protent.open)(0);
546		}
547		open_ccp_flag = 0;
548	    }
549	    reap_kids();	/* Don't leave dead kids lying around */
550	}
551
552	/*
553	 * If we may want to bring the link up again, transfer
554	 * the ppp unit back to the loopback.  Set the
555	 * real serial device back to its normal mode of operation.
556	 */
557	clean_check();
558	if (demand)
559	    restore_loop();
560	disestablish_ppp(ttyfd);
561
562	/*
563	 * Run disconnector script, if requested.
564	 * XXX we may not be able to do this if the line has hung up!
565	 */
566	if (disconnector && !hungup) {
567	    set_up_tty(ttyfd, 1);
568	    if (device_script(disconnector, ttyfd, ttyfd) < 0) {
569		syslog(LOG_WARNING, "disconnect script failed");
570	    } else {
571		syslog(LOG_INFO, "Serial link disconnected.");
572	    }
573	}
574
575    fail:
576	if (ttyfd >= 0)
577	    close_tty();
578	if (locked) {
579	    unlock();
580	    locked = 0;
581	}
582
583	if (!persist)
584	    die(1);
585
586	if (holdoff > 0 && need_holdoff) {
587	    phase = PHASE_HOLDOFF;
588	    TIMEOUT(holdoff_end, NULL, holdoff);
589	    do {
590		wait_time(timeleft(&timo));
591		calltimeout();
592		if (kill_link) {
593		    if (!persist)
594			die(0);
595		    kill_link = 0;
596		    phase = PHASE_DORMANT; /* allow signal to end holdoff */
597		}
598		reap_kids();
599	    } while (phase == PHASE_HOLDOFF);
600	}
601    }
602
603    die(0);
604    return 0;
605}
606
607/*
608 * detach - detach us from the controlling terminal.
609 */
610void
611detach()
612{
613    if (detached)
614	return;
615    if (daemon(0, 0) < 0) {
616	perror("Couldn't detach from controlling terminal");
617	die(1);
618    }
619    detached = 1;
620    pid = getpid();
621}
622
623/*
624 * holdoff_end - called via a timeout when the holdoff period ends.
625 */
626static void
627holdoff_end(arg)
628    void *arg;
629{
630    phase = PHASE_DORMANT;
631}
632
633/*
634 * get_input - called when incoming data is available.
635 */
636static void
637get_input()
638{
639    int len, i;
640    u_char *p;
641    u_short protocol;
642    struct protent *protp;
643
644    p = inpacket_buf;	/* point to beginning of packet buffer */
645
646    len = read_packet(inpacket_buf);
647    if (len < 0)
648	return;
649
650    if (len == 0) {
651	syslog(LOG_NOTICE, "Modem hangup");
652	hungup = 1;
653	lcp_lowerdown(0);	/* serial link is no longer available */
654	link_terminated(0);
655	return;
656    }
657
658    if (debug /*&& (debugflags & DBG_INPACKET)*/)
659	log_packet(p, len, "rcvd ", LOG_DEBUG);
660
661    if (len < PPP_HDRLEN) {
662	MAINDEBUG((LOG_INFO, "io(): Received short packet."));
663	return;
664    }
665
666    p += 2;				/* Skip address and control */
667    GETSHORT(protocol, p);
668    len -= PPP_HDRLEN;
669
670    /*
671     * Toss all non-LCP packets unless LCP is OPEN.
672     */
673    if (protocol != PPP_LCP && lcp_fsm[0].state != OPENED) {
674	MAINDEBUG((LOG_INFO,
675		   "get_input: Received non-LCP packet when LCP not open."));
676	return;
677    }
678
679    /*
680     * Until we get past the authentication phase, toss all packets
681     * except LCP, LQR and authentication packets.
682     */
683    if (phase <= PHASE_AUTHENTICATE
684	&& !(protocol == PPP_LCP || protocol == PPP_LQR
685	|| protocol == PPP_PAP || protocol == PPP_CHAP)) {
686	MAINDEBUG((LOG_INFO, "get_input: discarding proto 0x%x in phase %d",
687		   protocol, phase));
688	return;
689    }
690
691    /*
692     * Upcall the proper protocol input routine.
693     */
694    for (i = 0; (protp = protocols[i]) != NULL; ++i) {
695	if (protp->protocol == protocol && protp->enabled_flag) {
696	    (*protp->input)(0, p, len);
697	    return;
698	}
699	if (protocol == (protp->protocol & ~0x8000) && protp->enabled_flag
700	    && protp->datainput != NULL) {
701	    (*protp->datainput)(0, p, len);
702	    return;
703	}
704    }
705
706    if (debug)
707    	syslog(LOG_WARNING, "Unsupported protocol (0x%x) received", protocol);
708    lcp_sprotrej(0, p - PPP_HDRLEN, len + PPP_HDRLEN);
709}
710
711
712/*
713 * quit - Clean up state and exit (with an error indication).
714 */
715void
716quit()
717{
718    die(1);
719}
720
721/*
722 * die - like quit, except we can specify an exit status.
723 */
724void
725die(status)
726    int status;
727{
728    struct syslog_data sdata = SYSLOG_DATA_INIT;
729
730    cleanup();
731    syslog_r(LOG_INFO, &sdata, "Exit.");
732    _exit(status);
733}
734
735/*
736 * cleanup - restore anything which needs to be restored before we exit
737 */
738static void
739cleanup()
740{
741    sys_cleanup();
742
743    if (ttyfd >= 0)
744	close_tty();
745
746    if (locked)
747	unlock();
748}
749
750/*
751 * close_tty - restore the terminal device and close it.
752 */
753static void
754close_tty()
755{
756    disestablish_ppp(ttyfd);
757
758    /* drop dtr to hang up */
759    if (modem) {
760	setdtr(ttyfd, FALSE);
761	/*
762	 * This sleep is in case the serial port has CLOCAL set by default,
763	 * and consequently will reassert DTR when we close the device.
764	 */
765	sleep(1);
766    }
767
768    restore_tty(ttyfd);
769
770    if (tty_mode != (mode_t) -1)
771	fchmod(ttyfd, tty_mode);
772
773    close(ttyfd);
774    ttyfd = -1;
775}
776
777
778struct	callout {
779    struct timeval	c_time;		/* time at which to call routine */
780    void		*c_arg;		/* argument to routine */
781    void		(*c_func)(void *); /* routine */
782    struct		callout *c_next;
783};
784
785static struct callout *callout = NULL;	/* Callout list */
786static struct timeval timenow;		/* Current time */
787
788/*
789 * timeout - Schedule a timeout.
790 *
791 * Note that this timeout takes the number of seconds, NOT hz (as in
792 * the kernel).
793 */
794void
795timeout(func, arg, time)
796    void (*func)(void *);
797    void *arg;
798    int time;
799{
800    struct callout *newp, *p, **pp;
801
802    MAINDEBUG((LOG_DEBUG, "Timeout %lx:%lx in %d seconds.",
803	       (long) func, (long) arg, time));
804
805    /*
806     * Allocate timeout.
807     */
808    if ((newp = (struct callout *) malloc(sizeof(struct callout))) == NULL) {
809	syslog(LOG_ERR, "Out of memory in timeout()!");
810	die(1);
811    }
812    newp->c_arg = arg;
813    newp->c_func = func;
814    gettimeofday(&timenow, NULL);
815    newp->c_time.tv_sec = timenow.tv_sec + time;
816    newp->c_time.tv_usec = timenow.tv_usec;
817
818    /*
819     * Find correct place and link it in.
820     */
821    for (pp = &callout; (p = *pp); pp = &p->c_next)
822	if (newp->c_time.tv_sec < p->c_time.tv_sec
823	    || (newp->c_time.tv_sec == p->c_time.tv_sec
824		&& newp->c_time.tv_usec < p->c_time.tv_sec))
825	    break;
826    newp->c_next = p;
827    *pp = newp;
828}
829
830
831/*
832 * untimeout - Unschedule a timeout.
833 */
834void
835untimeout(func, arg)
836    void (*func)(void *);
837    void *arg;
838{
839    struct callout **copp, *freep;
840
841    MAINDEBUG((LOG_DEBUG, "Untimeout %lx:%lx.", (long) func, (long) arg));
842
843    /*
844     * Find first matching timeout and remove it from the list.
845     */
846    for (copp = &callout; (freep = *copp); copp = &freep->c_next)
847	if (freep->c_func == func && freep->c_arg == arg) {
848	    *copp = freep->c_next;
849	    (void) free((char *) freep);
850	    break;
851	}
852}
853
854
855/*
856 * calltimeout - Call any timeout routines which are now due.
857 */
858static void
859calltimeout()
860{
861    struct callout *p;
862
863    while (callout != NULL) {
864	p = callout;
865
866	if (gettimeofday(&timenow, NULL) < 0) {
867	    syslog(LOG_ERR, "Failed to get time of day: %m");
868	    die(1);
869	}
870	if (!(p->c_time.tv_sec < timenow.tv_sec
871	      || (p->c_time.tv_sec == timenow.tv_sec
872		  && p->c_time.tv_usec <= timenow.tv_usec)))
873	    break;		/* no, it's not time yet */
874
875	callout = p->c_next;
876	(*p->c_func)(p->c_arg);
877
878	free((char *) p);
879    }
880}
881
882
883/*
884 * timeleft - return the length of time until the next timeout is due.
885 */
886static struct timeval *
887timeleft(tvp)
888    struct timeval *tvp;
889{
890    if (callout == NULL)
891	return NULL;
892
893    gettimeofday(&timenow, NULL);
894    tvp->tv_sec = callout->c_time.tv_sec - timenow.tv_sec;
895    tvp->tv_usec = callout->c_time.tv_usec - timenow.tv_usec;
896    if (tvp->tv_usec < 0) {
897	tvp->tv_usec += 1000000;
898	tvp->tv_sec -= 1;
899    }
900    if (tvp->tv_sec < 0)
901	tvp->tv_sec = tvp->tv_usec = 0;
902
903    return tvp;
904}
905
906
907/*
908 * kill_my_pg - send a signal to our process group, and ignore it ourselves.
909 */
910static void
911kill_my_pg(sig)
912    int sig;
913{
914    struct sigaction act, oldact;
915
916    act.sa_handler = SIG_IGN;
917    act.sa_flags = 0;
918    kill(0, sig);
919    sigaction(sig, &act, &oldact);
920    sigaction(sig, &oldact, NULL);
921}
922
923
924/*
925 * hup - Catch SIGHUP signal.
926 *
927 * Indicates that the physical layer has been disconnected.
928 * We don't rely on this indication; if the user has sent this
929 * signal, we just take the link down.
930 */
931static void
932hup(sig)
933    int sig;
934{
935    int save_errno = errno;
936    struct syslog_data sdata = SYSLOG_DATA_INIT;
937
938    if (crashed)
939	_exit(127);
940    syslog_r(LOG_INFO, &sdata, "Hangup (SIGHUP)");
941    kill_link = 1;
942    if (conn_running)
943	/* Send the signal to the [dis]connector process(es) also */
944	kill_my_pg(sig);
945    errno = save_errno;
946}
947
948
949/*
950 * term - Catch SIGTERM signal and SIGINT signal (^C/del).
951 *
952 * Indicates that we should initiate a graceful disconnect and exit.
953 */
954static void
955term(sig)
956    int sig;
957{
958    int save_errno = errno;
959    struct syslog_data sdata = SYSLOG_DATA_INIT;
960
961    if (crashed)
962	_exit(127);
963    syslog_r(LOG_INFO, &sdata, "Terminating on signal %d.", sig);
964    persist = 0;		/* don't try to restart */
965    kill_link = 1;
966    if (conn_running)
967	/* Send the signal to the [dis]connector process(es) also */
968	kill_my_pg(sig);
969    errno = save_errno;
970}
971
972
973/*
974 * chld - Catch SIGCHLD signal.
975 * Calls reap_kids to get status for any dead kids.
976 */
977static void
978chld(sig)
979    int sig;
980{
981    int save_errno = errno;
982
983    reap_kids();		/* XXX somewhat unsafe */
984    errno = save_errno;
985}
986
987
988/*
989 * toggle_debug - Catch SIGUSR1 signal.
990 *
991 * Toggle debug flag.
992 */
993static void
994toggle_debug(sig)
995    int sig;
996{
997    debug = !debug;
998    if (debug) {
999	setlogmask(LOG_UPTO(LOG_DEBUG));	/* XXX safe, but wrong */
1000    } else {
1001	setlogmask(LOG_UPTO(LOG_WARNING));	/* XXX safe, but wrong */
1002    }
1003}
1004
1005
1006/*
1007 * open_ccp - Catch SIGUSR2 signal.
1008 *
1009 * Try to (re)negotiate compression.
1010 */
1011static void
1012open_ccp(sig)
1013    int sig;
1014{
1015    open_ccp_flag = 1;
1016}
1017
1018
1019/*
1020 * bad_signal - We've caught a fatal signal.  Clean up state and exit.
1021 */
1022static void
1023bad_signal(sig)
1024    int sig;
1025{
1026    struct syslog_data sdata = SYSLOG_DATA_INIT;
1027
1028    if (crashed)
1029	_exit(127);
1030    crashed = 1;
1031    syslog_r(LOG_ERR, &sdata, "Fatal signal %d", sig);
1032    if (conn_running)
1033	kill_my_pg(SIGTERM);
1034    die(1);					/* XXX unsafe! */
1035}
1036
1037
1038/*
1039 * device_script - run a program to connect or disconnect the
1040 * serial device.
1041 */
1042static int
1043device_script(program, in, out)
1044    char *program;
1045    int in, out;
1046{
1047    pid_t pid;
1048    int status;
1049    int errfd;
1050    gid_t gid;
1051    uid_t uid;
1052
1053    conn_running = 1;
1054    pid = fork();
1055
1056    if (pid < 0) {
1057	conn_running = 0;
1058	syslog(LOG_ERR, "Failed to create child process: %m");
1059	die(1);
1060    }
1061
1062    if (pid == 0) {
1063	sys_close();
1064	closelog();
1065	if (in == out) {
1066	    if (in != 0) {
1067		dup2(in, 0);
1068		close(in);
1069	    }
1070	    dup2(0, 1);
1071	} else {
1072	    if (out == 0)
1073		out = dup(out);
1074	    if (in != 0) {
1075		dup2(in, 0);
1076		close(in);
1077	    }
1078	    if (out != 1) {
1079		dup2(out, 1);
1080		close(out);
1081	    }
1082	}
1083	if (nodetach == 0) {
1084	    close(2);
1085	    errfd = open(_PATH_CONNERRS, O_WRONLY | O_APPEND | O_CREAT, 0600);
1086	    if (errfd >= 0 && errfd != 2) {
1087		dup2(errfd, 2);
1088		close(errfd);
1089	    }
1090	}
1091
1092	/* revoke privs */
1093	gid = getgid();
1094	uid = getuid();
1095	if (setresgid(gid, gid, gid) == -1 || setresuid(uid, uid, uid) == -1) {
1096		syslog(LOG_ERR, "revoke privileges: %s", strerror(errno));
1097		_exit(1);
1098	}
1099
1100	execl("/bin/sh", "sh", "-c", program, (char *)NULL);
1101	syslog(LOG_ERR, "could not exec /bin/sh: %m");
1102	_exit(99);
1103	/* NOTREACHED */
1104    }
1105
1106    while (waitpid(pid, &status, 0) < 0) {
1107	if (errno == EINTR)
1108	    continue;
1109	syslog(LOG_ERR, "error waiting for (dis)connection process: %m");
1110	die(1);
1111    }
1112    conn_running = 0;
1113
1114    return (status == 0 ? 0 : -1);
1115}
1116
1117
1118/*
1119 * run-program - execute a program with given arguments,
1120 * but don't wait for it.
1121 * If the program can't be executed, logs an error unless
1122 * must_exist is 0 and the program file doesn't exist.
1123 */
1124int
1125run_program(prog, args, must_exist)
1126    char *prog;
1127    char **args;
1128    int must_exist;
1129{
1130    pid_t pid;
1131    uid_t uid;
1132    gid_t gid;
1133
1134    pid = fork();
1135    if (pid == -1) {
1136	syslog(LOG_ERR, "Failed to create child process for %s: %m", prog);
1137	return -1;
1138    }
1139    if (pid == 0) {
1140	int new_fd;
1141
1142	/* Leave the current location */
1143	(void) setsid();    /* No controlling tty. */
1144	(void) umask (S_IRWXG|S_IRWXO);
1145	(void) chdir ("/"); /* no current directory. */
1146
1147	/* revoke privs */
1148	uid = getuid();
1149	gid = getgid();
1150	if (setresgid(gid, gid, gid) == -1 || setresuid(uid, uid, uid) == -1) {
1151		syslog(LOG_ERR, "revoke privileges: %s", strerror(errno));
1152		_exit(1);
1153	}
1154
1155	/* Ensure that nothing of our device environment is inherited. */
1156	sys_close();
1157	closelog();
1158	close (0);
1159	close (1);
1160	close (2);
1161	close (ttyfd);  /* tty interface to the ppp device */
1162
1163	/* Don't pass handles to the PPP device, even by accident. */
1164	new_fd = open (_PATH_DEVNULL, O_RDWR);
1165	if (new_fd >= 0) {
1166	    if (new_fd != 0) {
1167		dup2  (new_fd, 0); /* stdin <- /dev/null */
1168		close (new_fd);
1169	    }
1170	    dup2 (0, 1); /* stdout -> /dev/null */
1171	    dup2 (0, 2); /* stderr -> /dev/null */
1172	}
1173
1174	/* Force the priority back to zero if pppd is running higher. */
1175	if (setpriority (PRIO_PROCESS, 0, 0) < 0)
1176	    syslog (LOG_WARNING, "can't reset priority to 0: %m");
1177
1178	/* SysV recommends a second fork at this point. */
1179
1180	/* run the program; give it a null environment */
1181	execve(prog, args, script_env);
1182	if (must_exist || errno != ENOENT)
1183	    syslog(LOG_WARNING, "Can't execute %s: %m", prog);
1184	_exit(1);
1185    }
1186    MAINDEBUG((LOG_DEBUG, "Script %s started; pid = %ld", prog, (long)pid));
1187    ++n_children;
1188    return 0;
1189}
1190
1191
1192/*
1193 * reap_kids - get status from any dead child processes,
1194 * and log a message for abnormal terminations.
1195 */
1196static void
1197reap_kids()
1198{
1199    int status;
1200    pid_t pid;
1201
1202    if (n_children == 0)
1203	return;
1204    if ((pid = waitpid(-1, &status, WNOHANG)) == -1) {
1205	if (errno != ECHILD)
1206	    syslog(LOG_ERR, "Error waiting for child process: %m");
1207	return;
1208    }
1209    if (pid > 0) {
1210	--n_children;
1211	if (WIFSIGNALED(status)) {
1212	    syslog(LOG_WARNING, "Child process %ld terminated with signal %d",
1213		   (long)pid, WTERMSIG(status));
1214	}
1215    }
1216}
1217
1218
1219/*
1220 * log_packet - format a packet and log it.
1221 */
1222
1223char line[256];			/* line to be logged accumulated here */
1224char *linep;
1225
1226void
1227log_packet(p, len, prefix, level)
1228    u_char *p;
1229    int len;
1230    char *prefix;
1231    int level;
1232{
1233    strlcpy(line, prefix, sizeof line);
1234    linep = line + strlen(line);
1235    format_packet(p, len, pr_log, NULL);
1236    if (linep != line)
1237	syslog(level, "%s", line);
1238}
1239
1240/*
1241 * format_packet - make a readable representation of a packet,
1242 * calling `printer(arg, format, ...)' to output it.
1243 */
1244void
1245format_packet(p, len, printer, arg)
1246    u_char *p;
1247    int len;
1248    void (*printer)(void *, char *, ...);
1249    void *arg;
1250{
1251    int i, n;
1252    u_short proto;
1253    u_char x;
1254    struct protent *protp;
1255
1256    if (len >= PPP_HDRLEN && p[0] == PPP_ALLSTATIONS && p[1] == PPP_UI) {
1257	p += 2;
1258	GETSHORT(proto, p);
1259	len -= PPP_HDRLEN;
1260	for (i = 0; (protp = protocols[i]) != NULL; ++i)
1261	    if (proto == protp->protocol)
1262		break;
1263	if (protp != NULL) {
1264	    printer(arg, "[%s", protp->name);
1265	    n = (*protp->printpkt)(p, len, printer, arg);
1266	    printer(arg, "]");
1267	    p += n;
1268	    len -= n;
1269	} else {
1270	    printer(arg, "[proto=0x%x]", proto);
1271	}
1272    }
1273
1274    for (; len > 0; --len) {
1275	GETCHAR(x, p);
1276	printer(arg, " %.2x", x);
1277    }
1278}
1279
1280static void
1281pr_log(void *arg, char *fmt, ...)
1282{
1283    int n;
1284    va_list pvar;
1285    char buf[256];
1286
1287    va_start(pvar, fmt);
1288
1289    n = vfmtmsg(buf, sizeof(buf), fmt, pvar);
1290    va_end(pvar);
1291
1292    if (linep + n + 1 > line + sizeof(line)) {
1293	syslog(LOG_DEBUG, "%s", line);
1294	linep = line;
1295    }
1296    strlcpy(linep, buf, line + sizeof line - linep);
1297    linep += n;
1298}
1299
1300/*
1301 * print_string - print a readable representation of a string using
1302 * printer.
1303 */
1304void
1305print_string(p, len, printer, arg)
1306    char *p;
1307    int len;
1308    void (*printer)(void *, char *, ...);
1309    void *arg;
1310{
1311    int c;
1312
1313    printer(arg, "\"");
1314    for (; len > 0; --len) {
1315	c = *p++;
1316	if (' ' <= c && c <= '~') {
1317	    if (c == '\\' || c == '"')
1318		printer(arg, "\\");
1319	    printer(arg, "%c", c);
1320	} else {
1321	    switch (c) {
1322	    case '\n':
1323		printer(arg, "\\n");
1324		break;
1325	    case '\r':
1326		printer(arg, "\\r");
1327		break;
1328	    case '\t':
1329		printer(arg, "\\t");
1330		break;
1331	    default:
1332		printer(arg, "\\%.3o", c);
1333	    }
1334	}
1335    }
1336    printer(arg, "\"");
1337}
1338
1339/*
1340 * novm - log an error message saying we ran out of memory, and die.
1341 */
1342void
1343novm(msg)
1344    char *msg;
1345{
1346    syslog(LOG_ERR, "Virtual memory exhausted allocating %s", msg);
1347    die(1);
1348}
1349
1350/*
1351 * fmtmsg - format a message into a buffer.  Like snprintf except we
1352 * also specify the length of the output buffer, and we handle
1353 * %m (error message) and %I (IP address) formats.
1354 * Doesn't do floating-point formats.
1355 * Returns the number of chars put into buf.
1356 */
1357int
1358fmtmsg(char *buf, int buflen, char *fmt, ...)
1359{
1360    va_list args;
1361    int n;
1362
1363    va_start(args, fmt);
1364    n = vfmtmsg(buf, buflen, fmt, args);
1365    va_end(args);
1366    return n;
1367}
1368
1369/*
1370 * vfmtmsg - like fmtmsg, takes a va_list instead of a list of args.
1371 */
1372#define OUTCHAR(c)	(buflen > 0? (--buflen, *buf++ = (c)): 0)
1373
1374int
1375vfmtmsg(buf, buflen, fmt, args)
1376    char *buf;
1377    int buflen;
1378    char *fmt;
1379    va_list args;
1380{
1381    int c, i, n;
1382    int width, prec, fillch;
1383    int base, len, neg, quoted;
1384    unsigned long val = 0;
1385    char *str, *f, *buf0;
1386    unsigned char *p;
1387    char num[32];
1388    time_t t;
1389    static char hexchars[] = "0123456789abcdef";
1390
1391    buf0 = buf;
1392    --buflen;
1393    while (buflen > 0) {
1394	for (f = fmt; *f != '%' && *f != 0; ++f)
1395	    ;
1396	if (f > fmt) {
1397	    len = f - fmt;
1398	    if (len > buflen)
1399		len = buflen;
1400	    memcpy(buf, fmt, len);
1401	    buf += len;
1402	    buflen -= len;
1403	    fmt = f;
1404	}
1405	if (*fmt == 0)
1406	    break;
1407	c = *++fmt;
1408	width = prec = 0;
1409	fillch = ' ';
1410	if (c == '0') {
1411	    fillch = '0';
1412	    c = *++fmt;
1413	}
1414	if (c == '*') {
1415	    width = va_arg(args, int);
1416	    c = *++fmt;
1417	} else {
1418	    while (isdigit(c)) {
1419		width = width * 10 + c - '0';
1420		c = *++fmt;
1421	    }
1422	}
1423	if (c == '.') {
1424	    c = *++fmt;
1425	    if (c == '*') {
1426		prec = va_arg(args, int);
1427		c = *++fmt;
1428	    } else {
1429		while (isdigit(c)) {
1430		    prec = prec * 10 + c - '0';
1431		    c = *++fmt;
1432		}
1433	    }
1434	}
1435	str = 0;
1436	base = 0;
1437	neg = 0;
1438	++fmt;
1439	switch (c) {
1440	case 'd':
1441	    i = va_arg(args, int);
1442	    if (i < 0) {
1443		neg = 1;
1444		val = -i;
1445	    } else
1446		val = i;
1447	    base = 10;
1448	    break;
1449	case 'o':
1450	    val = va_arg(args, unsigned int);
1451	    base = 8;
1452	    break;
1453	case 'x':
1454	    val = va_arg(args, unsigned int);
1455	    base = 16;
1456	    break;
1457	case 'p':
1458	    val = (unsigned long) va_arg(args, void *);
1459	    base = 16;
1460	    neg = 2;
1461	    break;
1462	case 's':
1463	    str = va_arg(args, char *);
1464	    break;
1465	case 'c':
1466	    num[0] = va_arg(args, int);
1467	    num[1] = 0;
1468	    str = num;
1469	    break;
1470	case 'm':
1471	    str = strerror(errno);
1472	    break;
1473	case 'I':
1474	    str = ip_ntoa(va_arg(args, u_int32_t));
1475	    break;
1476	case 't':
1477	    time(&t);
1478	    str = ctime(&t);
1479	    str += 4;		/* chop off the day name */
1480	    str[15] = 0;	/* chop off year and newline */
1481	    break;
1482	case 'v':		/* "visible" string */
1483	case 'q':		/* quoted string */
1484	    quoted = c == 'q';
1485	    p = va_arg(args, unsigned char *);
1486	    if (fillch == '0' && prec > 0) {
1487		n = prec;
1488	    } else {
1489		n = strlen((char *)p);
1490		if (prec > 0 && prec < n)
1491		    n = prec;
1492	    }
1493	    while (n > 0 && buflen > 0) {
1494		c = *p++;
1495		--n;
1496		if (!quoted && c >= 0x80) {
1497		    OUTCHAR('M');
1498		    OUTCHAR('-');
1499		    c -= 0x80;
1500		}
1501		if (quoted && (c == '"' || c == '\\'))
1502		    OUTCHAR('\\');
1503		if (c < 0x20 || (0x7f <= c && c < 0xa0)) {
1504		    if (quoted) {
1505			OUTCHAR('\\');
1506			switch (c) {
1507			case '\t':	OUTCHAR('t');	break;
1508			case '\n':	OUTCHAR('n');	break;
1509			case '\b':	OUTCHAR('b');	break;
1510			case '\f':	OUTCHAR('f');	break;
1511			default:
1512			    OUTCHAR('x');
1513			    OUTCHAR(hexchars[c >> 4]);
1514			    OUTCHAR(hexchars[c & 0xf]);
1515			}
1516		    } else {
1517			if (c == '\t')
1518			    OUTCHAR(c);
1519			else {
1520			    OUTCHAR('^');
1521			    OUTCHAR(c ^ 0x40);
1522			}
1523		    }
1524		} else
1525		    OUTCHAR(c);
1526	    }
1527	    continue;
1528	default:
1529	    *buf++ = '%';
1530	    if (c != '%')
1531		--fmt;		/* so %z outputs %z etc. */
1532	    --buflen;
1533	    continue;
1534	}
1535	if (base != 0) {
1536	    str = num + sizeof(num);
1537	    *--str = 0;
1538	    while (str > num + neg) {
1539		*--str = hexchars[val % base];
1540		val = val / base;
1541		if (--prec <= 0 && val == 0)
1542		    break;
1543	    }
1544	    switch (neg) {
1545	    case 1:
1546		*--str = '-';
1547		break;
1548	    case 2:
1549		*--str = 'x';
1550		*--str = '0';
1551		break;
1552	    }
1553	    len = num + sizeof(num) - 1 - str;
1554	} else {
1555	    len = strlen(str);
1556	    if (prec > 0 && len > prec)
1557		len = prec;
1558	}
1559	if (width > 0) {
1560	    if (width > buflen)
1561		width = buflen;
1562	    if ((n = width - len) > 0) {
1563		buflen -= n;
1564		for (; n > 0; --n)
1565		    *buf++ = fillch;
1566	    }
1567	}
1568	if (len > buflen)
1569	    len = buflen;
1570	memcpy(buf, str, len);
1571	buf += len;
1572	buflen -= len;
1573    }
1574    *buf = 0;
1575    return buf - buf0;
1576}
1577
1578/*
1579 * script_setenv - set an environment variable value to be used
1580 * for scripts that we run (e.g. ip-up, auth-up, etc.)
1581 */
1582void
1583script_setenv(var, value)
1584    char *var, *value;
1585{
1586    int vl = strlen(var);
1587    int i;
1588    char *p, *newstring;
1589
1590    if (asprintf(&newstring, "%s=%s", var, value) == -1)
1591	novm("script_setenv");
1592
1593    /* check if this variable is already set */
1594    if (script_env != 0) {
1595	for (i = 0; (p = script_env[i]) != 0; ++i) {
1596	    if (strncmp(p, var, vl) == 0 && p[vl] == '=') {
1597		free(p);
1598		script_env[i] = newstring;
1599		return;
1600	    }
1601	}
1602    } else {
1603	i = 0;
1604	script_env = (char **) calloc(16, sizeof(char *));
1605	if (script_env == 0)
1606	    novm("script_setenv");
1607	s_env_nalloc = 16;
1608    }
1609
1610    /* reallocate script_env with more space if needed */
1611    if (i + 1 >= s_env_nalloc) {
1612	int new_n = i + 17;
1613	char **newenv = reallocarray(script_env,
1614	    new_n, sizeof(char *));
1615	if (newenv == 0)
1616	    novm("script_setenv");
1617	script_env = newenv;
1618	s_env_nalloc = new_n;
1619    }
1620
1621    script_env[i] = newstring;
1622    script_env[i+1] = 0;
1623}
1624