xref: /openbsd-src/usr.sbin/mrouted/main.c (revision 3a3fbb3f2e2521ab7c4a56b7ff7462ebd9095ec5)
1 /*	$NetBSD: main.c,v 1.6 1995/12/10 10:07:05 mycroft Exp $	*/
2 
3 /*
4  * The mrouted program is covered by the license in the accompanying file
5  * named "LICENSE".  Use of the mrouted program represents acceptance of
6  * the terms and conditions listed in that file.
7  *
8  * The mrouted program is COPYRIGHT 1989 by The Board of Trustees of
9  * Leland Stanford Junior University.
10  */
11 
12 /*
13  * Written by Steve Deering, Stanford University, February 1989.
14  *
15  * (An earlier version of DVMRP was implemented by David Waitzman of
16  *  BBN STC by extending Berkeley's routed program.  Some of Waitzman's
17  *  extensions have been incorporated into mrouted, but none of the
18  *  original routed code has been adopted.)
19  */
20 
21 
22 #include "defs.h"
23 #ifdef __STDC__
24 #include <stdarg.h>
25 #else
26 #include <varargs.h>
27 #endif
28 #include <fcntl.h>
29 #include <util.h>
30 
31 #ifdef SNMP
32 #include "snmp.h"
33 #endif
34 
35 #ifndef lint
36 static char rcsid[] =
37 	"@(#) $Id: main.c,v 1.7 2001/12/01 23:27:23 miod Exp $";
38 #endif
39 
40 extern char *configfilename;
41 char versionstring[100];
42 
43 static char dumpfilename[] = _PATH_MROUTED_DUMP;
44 static char cachefilename[] = _PATH_MROUTED_CACHE;
45 static char genidfilename[] = _PATH_MROUTED_GENID;
46 
47 int cache_lifetime 	= DEFAULT_CACHE_LIFETIME;
48 int max_prune_lifetime 	= DEFAULT_CACHE_LIFETIME * 2;
49 
50 int debug = 0;
51 u_char pruning = 1;	/* Enable pruning by default */
52 
53 #ifdef SNMP
54 #define NHANDLERS	34
55 #else
56 #define NHANDLERS	2
57 #endif
58 
59 static struct ihandler {
60     int fd;			/* File descriptor		 */
61     ihfunc_t func;		/* Function to call with &fd_set */
62 } ihandlers[NHANDLERS];
63 static int nhandlers = 0;
64 
65 /*
66  * Forward declarations.
67  */
68 static void fasttimer __P((int));
69 static void done __P((int));
70 static void dump __P((int));
71 static void fdump __P((int));
72 static void cdump __P((int));
73 static void restart __P((int));
74 static void timer __P((void));
75 static void cleanup __P((void));
76 static void resetlogging __P((void *));
77 
78 /* To shut up gcc -Wstrict-prototypes */
79 int main __P((int argc, char **argv));
80 
81 int
82 register_input_handler(fd, func)
83     int fd;
84     ihfunc_t func;
85 {
86     if (nhandlers >= NHANDLERS)
87 	return -1;
88 
89     ihandlers[nhandlers].fd = fd;
90     ihandlers[nhandlers++].func = func;
91 
92     return 0;
93 }
94 
95 int
96 main(argc, argv)
97     int argc;
98     char *argv[];
99 {
100     register int recvlen;
101     int dummy;
102     FILE *fp;
103     struct timeval tv;
104     u_int32_t prev_genid;
105     int vers;
106     fd_set rfds, readers;
107     int nfds, n, i;
108     sigset_t mask, omask;
109 #ifdef SNMP
110     struct timeval  timeout, *tvp = &timeout;
111     struct timeval  sched, *svp = &sched, now, *nvp = &now;
112     int index, block;
113 #endif
114 
115     if (geteuid() != 0) {
116 	fprintf(stderr, "must be root\n");
117 	exit(1);
118     }
119     setlinebuf(stderr);
120 
121     argv++, argc--;
122     while (argc > 0 && *argv[0] == '-') {
123 	if (strcmp(*argv, "-d") == 0) {
124 	    if (argc > 1 && isdigit(*(argv + 1)[0])) {
125 		argv++, argc--;
126 		debug = atoi(*argv);
127 	    } else
128 		debug = DEFAULT_DEBUG;
129 	} else if (strcmp(*argv, "-c") == 0) {
130 	    if (argc > 1) {
131 		argv++, argc--;
132 		configfilename = *argv;
133 	    } else
134 		goto usage;
135 	} else if (strcmp(*argv, "-p") == 0) {
136 	    pruning = 0;
137 #ifdef SNMP
138    } else if (strcmp(*argv, "-P") == 0) {
139 	    if (argc > 1 && isdigit(*(argv + 1)[0])) {
140 		argv++, argc--;
141 		dest_port = atoi(*argv);
142 	    } else
143 		dest_port = DEFAULT_PORT;
144 #endif
145 	} else
146 	    goto usage;
147 	argv++, argc--;
148     }
149 
150     if (argc > 0) {
151 usage:	fprintf(stderr,
152 		"usage: mrouted [-p] [-c configfile] [-d [debug_level]]\n");
153 	exit(1);
154     }
155 
156     if (debug == 0) {
157 	/*
158 	 * Detach from the terminal
159 	 */
160 	int t;
161 
162 	if (fork()) exit(0);
163 	(void)close(0);
164 	(void)close(1);
165 	(void)close(2);
166 	(void)open("/", 0);
167 	(void)dup2(0, 1);
168 	(void)dup2(0, 2);
169 #ifdef SYSV
170 	(void)setpgrp();
171 #else
172 #ifdef TIOCNOTTY
173 	t = open("/dev/tty", 2);
174 	if (t >= 0) {
175 	    (void)ioctl(t, TIOCNOTTY, (char *)0);
176 	    (void)close(t);
177 	}
178 #else
179 	if (setsid() < 0)
180 	    perror("setsid");
181 #endif
182 #endif
183     }
184     else
185 	fprintf(stderr, "debug level %u\n", debug);
186 
187 #ifdef LOG_DAEMON
188     (void)openlog("mrouted", LOG_PID, LOG_DAEMON);
189     (void)setlogmask(LOG_UPTO(LOG_NOTICE));
190 #else
191     (void)openlog("mrouted", LOG_PID);
192 #endif
193     sprintf(versionstring, "mrouted version %d.%d",
194 			PROTOCOL_VERSION, MROUTED_VERSION);
195 
196     log(LOG_NOTICE, 0, "%s", versionstring);
197 
198 #ifdef SYSV
199     srand48(time(NULL));
200 #else
201     srandom(gethostid());
202 #endif
203 
204     /*
205      * Get generation id
206      */
207     gettimeofday(&tv, 0);
208     dvmrp_genid = tv.tv_sec;
209 
210     fp = fopen(genidfilename, "r");
211     if (fp != NULL) {
212 	fscanf(fp, "%d", &prev_genid);
213 	if (prev_genid == dvmrp_genid)
214 	    dvmrp_genid++;
215 	(void) fclose(fp);
216     }
217 
218     fp = fopen(genidfilename, "w");
219     if (fp != NULL) {
220 	fprintf(fp, "%d", dvmrp_genid);
221 	(void) fclose(fp);
222     }
223 
224     callout_init();
225     init_igmp();
226     init_routes();
227     init_ktable();
228     k_init_dvmrp();		/* enable DVMRP routing in kernel */
229 
230 #ifndef OLD_KERNEL
231     vers = k_get_version();
232     /*XXX
233      * This function must change whenever the kernel version changes
234      */
235     if ((((vers >> 8) & 0xff) != 3) ||
236 	 ((vers & 0xff) != 5))
237 	log(LOG_ERR, 0, "kernel (v%d.%d)/mrouted (v%d.%d) version mismatch",
238 		(vers >> 8) & 0xff, vers & 0xff,
239 		PROTOCOL_VERSION, MROUTED_VERSION);
240 #endif
241 
242 #ifdef SNMP
243     if (i = snmp_init())
244        return i;
245 
246     gettimeofday(nvp, 0);
247     if (nvp->tv_usec < 500000L){
248    svp->tv_usec = nvp->tv_usec + 500000L;
249    svp->tv_sec = nvp->tv_sec;
250     } else {
251    svp->tv_usec = nvp->tv_usec - 500000L;
252    svp->tv_sec = nvp->tv_sec + 1;
253     }
254 #endif /* SNMP */
255 
256     init_vifs();
257 
258 #ifdef RSRR
259     rsrr_init();
260 #endif /* RSRR */
261 
262 #if defined(__STDC__) || defined(__GNUC__)
263     /*
264      * Allow cleanup if unexpected exit.  Apparently some architectures
265      * have a kernel bug where closing the socket doesn't do an
266      * ip_mrouter_done(), so we attempt to do it on exit.
267      */
268     atexit(cleanup);
269 #endif
270 
271     if (debug)
272 	fprintf(stderr, "pruning %s\n", pruning ? "on" : "off");
273 
274     pidfile(NULL);
275 
276     (void)signal(SIGALRM, fasttimer);
277 
278     (void)signal(SIGHUP,  restart);
279     (void)signal(SIGTERM, done);
280     (void)signal(SIGINT,  done);
281     (void)signal(SIGUSR1, fdump);
282     (void)signal(SIGUSR2, cdump);
283     if (debug != 0)
284 	(void)signal(SIGQUIT, dump);
285 
286     FD_ZERO(&readers);
287     FD_SET(igmp_socket, &readers);
288     nfds = igmp_socket + 1;
289     for (i = 0; i < nhandlers; i++) {
290 	FD_SET(ihandlers[i].fd, &readers);
291 	if (ihandlers[i].fd >= nfds)
292 	    nfds = ihandlers[i].fd + 1;
293     }
294 
295     /*
296      * Install the vifs in the kernel as late as possible in the
297      * initialization sequence.
298      */
299     init_installvifs();
300 
301     if (debug >= 2) dump(0);
302 
303     /* Start up the log rate-limiter */
304     resetlogging(NULL);
305 
306     (void)alarm(1);	 /* schedule first timer interrupt */
307 
308     /*
309      * Main receive loop.
310      */
311     dummy = 0;
312     for(;;) {
313 	bcopy((char *)&readers, (char *)&rfds, sizeof(rfds));
314 #ifdef SNMP
315    gettimeofday(nvp, 0);
316    if (nvp->tv_sec > svp->tv_sec
317        || (nvp->tv_sec == svp->tv_sec && nvp->tv_usec > svp->tv_usec)){
318        alarmTimer(nvp);
319        eventTimer(nvp);
320        if (nvp->tv_usec < 500000L){
321       svp->tv_usec = nvp->tv_usec + 500000L;
322       svp->tv_sec = nvp->tv_sec;
323        } else {
324       svp->tv_usec = nvp->tv_usec - 500000L;
325       svp->tv_sec = nvp->tv_sec + 1;
326        }
327    }
328 
329 	tvp =  &timeout;
330 	tvp->tv_sec = 0;
331 	tvp->tv_usec = 500000L;
332 
333 	block = 0;
334 	snmp_select_info(&nfds, &rfds, tvp, &block);
335 	if (block == 1)
336 		tvp = NULL; /* block without timeout */
337 	if ((n = select(nfds, &rfds, NULL, NULL, tvp)) < 0)
338 #else
339 	if ((n = select(nfds, &rfds, NULL, NULL, NULL)) < 0)
340 #endif
341    {
342             if (errno != EINTR) /* SIGALRM is expected */
343                 log(LOG_WARNING, errno, "select failed");
344             continue;
345         }
346 
347 	if (FD_ISSET(igmp_socket, &rfds)) {
348 	    recvlen = recvfrom(igmp_socket, recv_buf, RECV_BUF_SIZE,
349 			       0, NULL, &dummy);
350 	    if (recvlen < 0) {
351 		if (errno != EINTR) log(LOG_ERR, errno, "recvfrom");
352 		continue;
353 	    }
354 	    (void)sigemptyset(&mask);
355 	    (void)sigaddset(&mask, SIGALRM);
356 	    if (sigprocmask(SIG_BLOCK, &mask, &omask) < 0)
357 		    log(LOG_ERR, errno, "sigprocmask");
358 	    accept_igmp(recvlen);
359 	    (void)sigprocmask(SIG_SETMASK, &omask, NULL);
360         }
361 
362 	for (i = 0; i < nhandlers; i++) {
363 	    if (FD_ISSET(ihandlers[i].fd, &rfds)) {
364 		(*ihandlers[i].func)(ihandlers[i].fd, &rfds);
365 	    }
366 	}
367 
368 #ifdef SNMP
369 	snmp_read(&rfds);
370 	snmp_timeout(); /* poll */
371 #endif
372     }
373 }
374 
375 
376 /*
377  * routine invoked every second.  Its main goal is to cycle through
378  * the routing table and send partial updates to all neighbors at a
379  * rate that will cause the entire table to be sent in ROUTE_REPORT_INTERVAL
380  * seconds.  Also, every TIMER_INTERVAL seconds it calls timer() to
381  * do all the other time-based processing.
382  */
383 static void
384 fasttimer(i)
385     int i;
386 {
387     static unsigned int tlast;
388     static unsigned int nsent;
389     register unsigned int t = tlast + 1;
390     register int n;
391 
392     /*
393      * if we're in the last second, send everything that's left.
394      * otherwise send at least the fraction we should have sent by now.
395      */
396     if (t >= ROUTE_REPORT_INTERVAL) {
397 	register int nleft = nroutes - nsent;
398 	while (nleft > 0) {
399 	    if ((n = report_next_chunk()) <= 0)
400 		break;
401 	    nleft -= n;
402 	}
403 	tlast = 0;
404 	nsent = 0;
405     } else {
406 	register unsigned int ncum = nroutes * t / ROUTE_REPORT_INTERVAL;
407 	while (nsent < ncum) {
408 	    if ((n = report_next_chunk()) <= 0)
409 		break;
410 	    nsent += n;
411 	}
412 	tlast = t;
413     }
414     if ((t % TIMER_INTERVAL) == 0)
415 	timer();
416 
417     age_callout_queue();/* Advance the timer for the callout queue
418 				for groups */
419     alarm(1);
420 }
421 
422 /*
423  * The 'virtual_time' variable is initialized to a value that will cause the
424  * first invocation of timer() to send a probe or route report to all vifs
425  * and send group membership queries to all subnets for which this router is
426  * querier.  This first invocation occurs approximately TIMER_INTERVAL seconds
427  * after the router starts up.   Note that probes for neighbors and queries
428  * for group memberships are also sent at start-up time, as part of initial-
429  * ization.  This repetition after a short interval is desirable for quickly
430  * building up topology and membership information in the presence of possible
431  * packet loss.
432  *
433  * 'virtual_time' advances at a rate that is only a crude approximation of
434  * real time, because it does not take into account any time spent processing,
435  * and because the timer intervals are sometimes shrunk by a random amount to
436  * avoid unwanted synchronization with other routers.
437  */
438 
439 static u_long virtual_time = 0;
440 
441 
442 /*
443  * Timer routine.  Performs periodic neighbor probing, route reporting, and
444  * group querying duties, and drives various timers in routing entries and
445  * virtual interface data structures.
446  */
447 static void
448 timer()
449 {
450     age_routes();	/* Advance the timers in the route entries     */
451     age_vifs();		/* Advance the timers for neighbors */
452     age_table_entry();	/* Advance the timers for the cache entries */
453 
454     if (virtual_time % GROUP_QUERY_INTERVAL == 0) {
455 	/*
456 	 * Time to query the local group memberships on all subnets
457 	 * for which this router is the elected querier.
458 	 */
459 	query_groups();
460     }
461 
462     if (virtual_time % NEIGHBOR_PROBE_INTERVAL == 0) {
463 	/*
464 	 * Time to send a probe on all vifs from which no neighbors have
465 	 * been heard.  Also, check if any inoperative interfaces have now
466 	 * come up.  (If they have, they will also be probed as part of
467 	 * their initialization.)
468 	 */
469 	probe_for_neighbors();
470 
471 	if (vifs_down)
472 	    check_vif_state();
473     }
474 
475     delay_change_reports = FALSE;
476     if (routes_changed) {
477 	/*
478 	 * Some routes have changed since the last timer interrupt, but
479 	 * have not been reported yet.  Report the changed routes to all
480 	 * neighbors.
481 	 */
482 	report_to_all_neighbors(CHANGED_ROUTES);
483     }
484 
485 #ifdef SNMP
486     sync_timer();
487 #endif
488 
489     /*
490      * Advance virtual time
491      */
492     virtual_time += TIMER_INTERVAL;
493 }
494 
495 
496 /*
497  * On termination, let everyone know we're going away.
498  */
499 static void
500 done(i)
501     int i;
502 {
503     log(LOG_NOTICE, 0, "%s exiting", versionstring);
504     cleanup();
505     _exit(1);
506 }
507 
508 static void
509 cleanup()
510 {
511     static in_cleanup = 0;
512 
513     if (!in_cleanup) {
514 	in_cleanup++;
515 #ifdef RSRR
516 	rsrr_clean();
517 #endif /* RSRR */
518 	expire_all_routes();
519 	report_to_all_neighbors(ALL_ROUTES);
520 	k_stop_dvmrp();
521     }
522 }
523 
524 
525 /*
526  * Dump internal data structures to stderr.
527  */
528 static void
529 dump(i)
530     int i;
531 {
532     dump_vifs(stderr);
533     dump_routes(stderr);
534 }
535 
536 
537 /*
538  * Dump internal data structures to a file.
539  */
540 static void
541 fdump(i)
542     int i;
543 {
544     FILE *fp;
545 
546     fp = fopen(dumpfilename, "w");
547     if (fp != NULL) {
548 	dump_vifs(fp);
549 	dump_routes(fp);
550 	(void) fclose(fp);
551     }
552 }
553 
554 
555 /*
556  * Dump local cache contents to a file.
557  */
558 static void
559 cdump(i)
560     int i;
561 {
562     FILE *fp;
563 
564     fp = fopen(cachefilename, "w");
565     if (fp != NULL) {
566 	dump_cache(fp);
567 	(void) fclose(fp);
568     }
569 }
570 
571 
572 /*
573  * Restart mrouted
574  */
575 static void
576 restart(i)
577     int i;
578 {
579     sigset_t mask, omask;
580 
581     log(LOG_NOTICE, 0, "%s restart", versionstring);
582 
583     /*
584      * reset all the entries
585      */
586     (void)sigemptyset(&mask);
587     (void)sigaddset(&mask, SIGALRM);
588     if (sigprocmask(SIG_BLOCK, &mask, &omask) < 0)
589 	log(LOG_ERR, errno, "sigprocmask");
590     free_all_prunes();
591     free_all_routes();
592     stop_all_vifs();
593     k_stop_dvmrp();
594     close(igmp_socket);
595     close(udp_socket);
596 
597     /*
598      * start processing again
599      */
600     dvmrp_genid++;
601     pruning = 1;
602 
603     init_igmp();
604     init_routes();
605     init_ktable();
606     init_vifs();
607     k_init_dvmrp();		/* enable DVMRP routing in kernel */
608     init_installvifs();
609 
610     (void)sigprocmask(SIG_SETMASK, &omask, NULL);
611 }
612 
613 #define LOG_MAX_MSGS	20	/* if > 20/minute then shut up for a while */
614 #define LOG_SHUT_UP	600	/* shut up for 10 minutes */
615 static int log_nmsgs = 0;
616 
617 static void
618 resetlogging(arg)
619     void *arg;
620 {
621     int nxttime = 60;
622     void *narg = NULL;
623 
624     if (arg == NULL && log_nmsgs > LOG_MAX_MSGS) {
625 	nxttime = LOG_SHUT_UP;
626 	narg = (void *)&log_nmsgs;	/* just need some valid void * */
627 	syslog(LOG_WARNING, "logging too fast, shutting up for %d minutes",
628 			LOG_SHUT_UP / 60);
629     } else {
630 	log_nmsgs = 0;
631     }
632 
633     timer_setTimer(nxttime, resetlogging, narg);
634 }
635 
636 /*
637  * Log errors and other messages to the system log daemon and to stderr,
638  * according to the severity of the message and the current debug level.
639  * For errors of severity LOG_ERR or worse, terminate the program.
640  */
641 #ifdef __STDC__
642 void
643 log(int severity, int syserr, char *format, ...)
644 {
645     va_list ap;
646     static char fmt[211] = "warning - ";
647     char *msg;
648     char tbuf[20];
649     struct timeval now;
650     struct tm *thyme;
651     time_t t;
652 
653     va_start(ap, format);
654 #else
655 /*VARARGS3*/
656 void
657 log(severity, syserr, format, va_alist)
658     int severity, syserr;
659     char *format;
660     va_dcl
661 {
662     va_list ap;
663     static char fmt[211] = "warning - ";
664     char *msg;
665     char tbuf[20];
666     struct timeval now;
667     struct tm *thyme;
668     time_t t;
669 
670     va_start(ap);
671 #endif
672     vsprintf(&fmt[10], format, ap);
673     va_end(ap);
674     msg = (severity == LOG_WARNING) ? fmt : &fmt[10];
675 
676     switch (debug) {
677 	case 0: break;
678 	case 1: if (severity > LOG_NOTICE) break;
679 	case 2: if (severity > LOG_INFO  ) break;
680 	default:
681 	    gettimeofday(&now,NULL);
682 	    t = now.tv_sec;
683 	    thyme = localtime(&t);
684 	    strftime(tbuf, sizeof(tbuf), "%X.%%03d ", thyme);
685 	    fprintf(stderr, tbuf, now.tv_usec / 1000);
686 	    fprintf(stderr, "%s", msg);
687 	    if (syserr == 0)
688 		fprintf(stderr, "\n");
689 	    else if (syserr < sys_nerr)
690 		fprintf(stderr, ": %s\n", sys_errlist[syserr]);
691 	    else
692 		fprintf(stderr, ": errno %d\n", syserr);
693     }
694 
695     if (severity <= LOG_NOTICE) {
696 	if (log_nmsgs++ < LOG_MAX_MSGS) {
697 	    if (syserr != 0) {
698 		errno = syserr;
699 		syslog(severity, "%s: %m", msg);
700 	    } else
701 		syslog(severity, "%s", msg);
702 	}
703 
704 	if (severity <= LOG_ERR) exit(1);
705     }
706 }
707 
708 #ifdef DEBUG_MFC
709 void
710 md_log(what, origin, mcastgrp)
711     int what;
712     u_int32_t origin, mcastgrp;
713 {
714     static FILE *f = NULL;
715     struct timeval tv;
716     u_int32_t buf[4];
717 
718     if (!f) {
719 	if ((f = fopen("/tmp/mrouted.clog", "w")) == NULL) {
720 	    log(LOG_ERR, errno, "open /tmp/mrouted.clog");
721 	}
722     }
723 
724     gettimeofday(&tv, NULL);
725     buf[0] = tv.tv_sec;
726     buf[1] = what;
727     buf[2] = origin;
728     buf[3] = mcastgrp;
729 
730     fwrite(buf, sizeof(u_int32_t), 4, f);
731 }
732 #endif
733