xref: /netbsd-src/sbin/routed/main.c (revision 81b108b45f75f89f1e3ffad9fb6f074e771c0935)
1 /*	$NetBSD: main.c,v 1.14 1996/08/10 01:29:23 thorpej Exp $	*/
2 
3 /*
4  * Copyright (c) 1983, 1988, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. All advertising materials mentioning features or use of this software
16  *    must display the following acknowledgement:
17  *	This product includes software developed by the University of
18  *	California, Berkeley and its contributors.
19  * 4. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 char copyright[] =
37 "@(#) Copyright (c) 1983, 1988, 1993\n\
38 	The Regents of the University of California.  All rights reserved.\n";
39 #if !defined(lint) && !defined(sgi)
40 #if 0
41 static char sccsid[] = "@(#)main.c	8.1 (Berkeley) 6/5/93";
42 #else
43 static char rcsid[] = "$NetBSD: main.c,v 1.14 1996/08/10 01:29:23 thorpej Exp $";
44 #endif
45 #endif /* not lint */
46 
47 #include "defs.h"
48 #include "pathnames.h"
49 #ifdef sgi
50 #include "math.h"
51 #endif
52 #include <signal.h>
53 #include <fcntl.h>
54 #include <sys/file.h>
55 
56 pid_t	mypid;
57 
58 naddr	myaddr;				/* system address */
59 char	myname[MAXHOSTNAMELEN+1];
60 
61 int	supplier;			/* supply or broadcast updates */
62 int	supplier_set;
63 int	ipforwarding = 1;		/* kernel forwarding on */
64 
65 int	default_gateway;		/* 1=advertise default */
66 int	background = 1;
67 int	ridhosts;			/* 1=reduce host routes */
68 int	mhome;				/* 1=want multi-homed host route */
69 int	advertise_mhome;		/* 1=must continue adverising it */
70 int	auth_ok = 1;			/* 1=ignore auth if we do not care */
71 
72 struct timeval epoch;			/* when started */
73 struct timeval clk, prev_clk;
74 struct timeval now;			/* current idea of time */
75 time_t	now_stale;
76 time_t	now_garbage;
77 
78 struct timeval next_bcast;		/* next general broadcast */
79 struct timeval no_flash = {EPOCH+SUPPLY_INTERVAL};  /* inhibit flash update */
80 
81 fd_set	fdbits;
82 int	sock_max;
83 int	rip_sock = -1;			/* RIP socket */
84 struct interface *rip_sock_mcast;	/* current multicast interface */
85 int	rt_sock;			/* routing socket */
86 int	rt_sock_seqno;
87 
88 
89 static  int get_rip_sock(naddr, int);
90 static void timevalsub(struct timeval *, struct timeval *, struct timeval *);
91 
92 int
93 main(int argc,
94      char *argv[])
95 {
96 	int n, mib[4], off;
97 	size_t len;
98 	char *p, *q;
99 	struct timeval wtime, t2;
100 	time_t dt;
101 	fd_set ibits;
102 	naddr p_addr, p_mask;
103 	struct interface *ifp;
104 	struct parm parm;
105 	char *tracename = 0;
106 
107 
108 	openlog("routed", LOG_PID | LOG_ODELAY, LOG_DAEMON);
109 	ftrace = stdout;
110 
111 	gettimeofday(&clk, 0);
112 	prev_clk = clk;
113 	epoch = clk;
114 	epoch.tv_sec -= EPOCH;
115 	now.tv_sec = EPOCH;
116 	now_stale = EPOCH - STALE_TIME;
117 	now_garbage = EPOCH - GARBAGE_TIME;
118 	wtime.tv_sec = 0;
119 
120 	(void)gethostname(myname, sizeof(myname)-1);
121 	(void)gethost(myname, &myaddr);
122 
123 	while ((n = getopt(argc, argv, "sqdghmpAtT:F:P:")) != EOF) {
124 		switch (n) {
125 		case 's':
126 			supplier = 1;
127 			supplier_set = 1;
128 			break;
129 
130 		case 'q':
131 			supplier = 0;
132 			supplier_set = 1;
133 			break;
134 
135 		case 'd':
136 			background = 0;
137 			break;
138 
139 		case 'g':
140 			bzero(&parm, sizeof(parm));
141 			parm.parm_d_metric = 1;
142 			p = check_parms(&parm);
143 			if (p != 0)
144 				msglog("bad -g: %s", p);
145 			else
146 				default_gateway = 1;
147 			break;
148 
149 		case 'h':		/* suppress extra host routes */
150 			ridhosts = 1;
151 			break;
152 
153 		case 'm':		/* advertise host route */
154 			mhome = 1;	/* on multi-homed hosts */
155 			break;
156 
157 		case 'A':
158 			/* Ignore authentication if we do not care.
159 			 * Crazy as it is, that is what RFC 1723 requires.
160 			 */
161 			auth_ok = 0;
162 			break;
163 
164 		case 't':
165 			new_tracelevel++;
166 			break;
167 
168 		case 'T':
169 			tracename = optarg;
170 			break;
171 
172 		case 'F':		/* minimal routes for SLIP */
173 			n = HOPCNT_INFINITY-2;
174 			p = strchr(optarg,',');
175 			if (p && *p != '\0') {
176 				n = (int)strtoul(p+1, &q, 0);
177 				if (*q == '\0'
178 				    && n <= HOPCNT_INFINITY-1
179 				    && n >= 1)
180 					*p = '\0';
181 			}
182 			if (!getnet(optarg, &p_addr, &p_mask)) {
183 				msglog("bad network; \"-F %s\"",
184 				       optarg);
185 				break;
186 			}
187 			bzero(&parm, sizeof(parm));
188 			parm.parm_addr_h = ntohl(p_addr);
189 			parm.parm_mask = p_mask;
190 			parm.parm_d_metric = n;
191 			p = check_parms(&parm);
192 			if (p != 0)
193 				msglog("bad -F: %s", p);
194 			break;
195 
196 		case 'P':
197 			/* handle arbirary, (usually) per-interface
198 			 * parameters.
199 			 */
200 			p = parse_parms(optarg);
201 			if (p != 0)
202 				msglog("bad \"%s\" in \"%s\"",
203 				       p, optarg);
204 			break;
205 
206 		default:
207 			goto usage;
208 		}
209 	}
210 	argc -= optind;
211 	argv += optind;
212 
213 	if (tracename == 0 && argc >= 1) {
214 		tracename = *argv++;
215 		argc--;
216 	}
217 	if (argc != 0) {
218 usage:
219 		logbad(0, "usage: routed [-sqdghmpAt] [-T /tracefile]"
220 		       " [-F net[,metric]] [-P parms]");
221 	}
222 	if (geteuid() != 0)
223 		logbad(0, "requires UID 0");
224 
225 	mib[0] = CTL_NET;
226 	mib[1] = PF_INET;
227 	mib[2] = IPPROTO_IP;
228 	mib[3] = IPCTL_FORWARDING;
229 	len = sizeof(ipforwarding);
230 	if (sysctl(mib, 4, &ipforwarding, &len, 0, 0) < 0)
231 		LOGERR("sysctl(IPCTL_FORWARDING)");
232 
233 	if (!ipforwarding) {
234 		if (supplier)
235 			msglog("-s incompatible with ipforwarding=0");
236 		if (default_gateway) {
237 			msglog("-g incompatible with ipforwarding=0");
238 			default_gateway = 0;
239 		}
240 		supplier = 0;
241 		supplier_set = 1;
242 	}
243 	if (default_gateway) {
244 		if (supplier_set && !supplier) {
245 			msglog("-g and -q incompatible");
246 		} else {
247 			supplier = 1;
248 			supplier_set = 1;
249 		}
250 	}
251 
252 
253 	/* get into the background */
254 	if (background) {
255 #ifdef sgi
256 		if (0 > _daemonize(_DF_NOCHDIR,
257 				   new_tracelevel == 0 ? -1 : STDOUT_FILENO,
258 				   new_tracelevel == 0 ? -1 : STDERR_FILENO,
259 				   -1))
260 			BADERR(0, "_daemonize()");
261 #else
262 		if (daemon(1, 1) < 0)
263 			BADERR(0,"daemon()");
264 #endif
265 	}
266 
267 	mypid = getpid();
268 	srandom((int)(clk.tv_sec ^ clk.tv_usec ^ mypid));
269 
270 	/* prepare socket connected to the kernel.
271 	 */
272 	rt_sock = socket(AF_ROUTE, SOCK_RAW, 0);
273 	if (rt_sock < 0)
274 		BADERR(1,"rt_sock = socket()");
275 	if (fcntl(rt_sock, F_SETFL, O_NONBLOCK) == -1)
276 		logbad(1, "fcntl(rt_sock) O_NONBLOCK: %s", strerror(errno));
277 	off = 0;
278 	if (setsockopt(rt_sock, SOL_SOCKET,SO_USELOOPBACK,
279 		       &off,sizeof(off)) < 0)
280 		LOGERR("setsockopt(SO_USELOOPBACK,0)");
281 
282 	/* prepare Router Discovery socket.
283 	 */
284 	rdisc_sock = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
285 	if (rdisc_sock < 0)
286 		BADERR(1,"rdisc_sock = socket()");
287 	fix_sock(rdisc_sock,"rdisc_sock");
288 
289 	fix_select();
290 
291 
292 	if (background && new_tracelevel == 0)
293 		ftrace = 0;
294 	if (tracename != 0) {
295 		trace_on(tracename, 1);
296 		if (new_tracelevel == 0)	/* use stdout if file is bad */
297 			new_tracelevel = 1;
298 	}
299 	set_tracelevel();
300 
301 	/* initialize radix tree */
302 	rtinit();
303 
304 	/* Pick a random part of the second for our output to minimize
305 	 * collisions.
306 	 *
307 	 * Start broadcasting after hearing from other routers, and
308 	 * at a random time so a bunch of systems do not get synchronized
309 	 * after a power failure.
310 	 */
311 	intvl_random(&next_bcast, EPOCH+MIN_WAITTIME, EPOCH+SUPPLY_INTERVAL);
312 	age_timer.tv_usec = next_bcast.tv_usec;
313 	age_timer.tv_sec = EPOCH+MIN_WAITTIME;
314 	rdisc_timer = next_bcast;
315 	ifinit_timer.tv_usec = next_bcast.tv_usec;
316 
317 	signal(SIGALRM, sigalrm);
318 	signal(SIGHUP, sigterm);
319 	signal(SIGTERM, sigterm);
320 	signal(SIGINT, sigterm);
321 	signal(SIGUSR1, sigtrace_on);
322 	signal(SIGUSR2, sigtrace_off);
323 
324 	/* Collect an initial view of the world by checking the interface
325 	 * configuration and the kludge file.
326 	 */
327 	gwkludge();
328 	ifinit();
329 	flush_kern();
330 
331 	/* Ask for routes */
332 	rip_query();
333 	if (!supplier)
334 		rdisc_sol();
335 
336 	/* Loop forever, listening and broadcasting.
337 	 */
338 	for (;;) {
339 		prev_clk = clk;
340 		gettimeofday(&clk, 0);
341 		timevalsub(&t2, &clk, &prev_clk);
342 		if (t2.tv_sec < 0
343 		    || t2.tv_sec > wtime.tv_sec + 5) {
344 			/* Deal with time changes before other housekeeping to
345 			 * keep everything straight.
346 			 */
347 			dt = t2.tv_sec;
348 			if (dt > 0)
349 				dt -= wtime.tv_sec;
350 			trace_act("time changed by %d sec\n", dt);
351 			epoch.tv_sec += dt;
352 		}
353 		timevalsub(&now, &clk, &epoch);
354 		now_stale = now.tv_sec - STALE_TIME;
355 		now_garbage = now.tv_sec - GARBAGE_TIME;
356 
357 		/* deal with interrupts that should affect tracing */
358 		set_tracelevel();
359 
360 		if (stopint != 0) {
361 			if (supplier) {
362 				rip_bcast(0);
363 				rdisc_adv();
364 			}
365 			trace_off("exiting with signal %d\n", stopint);
366 			exit(stopint | 128);
367 		}
368 
369 		/* look for new or dead interfaces */
370 		timevalsub(&wtime, &ifinit_timer, &now);
371 		if (wtime.tv_sec <= 0) {
372 			wtime.tv_sec = 0;
373 			ifinit();
374 			rip_query();
375 			continue;
376 		}
377 
378 		/* If it is time, then broadcast our routes.
379 		 */
380 		if (supplier || advertise_mhome) {
381 			timevalsub(&t2, &next_bcast, &now);
382 			if (t2.tv_sec <= 0) {
383 				/* Synchronize the aging and broadcast
384 				 * timers to minimize awakenings
385 				 */
386 				age(0);
387 
388 				rip_bcast(0);
389 
390 				/* It is desirable to send routing updates
391 				 * regularly.  So schedule the next update
392 				 * 30 seconds after the previous one was
393 				 * secheduled, instead of 30 seconds after
394 				 * the previous update was finished.
395 				 * Even if we just started after discovering
396 				 * a 2nd interface or were otherwise delayed,
397 				 * pick a 30-second aniversary of the
398 				 * original broadcast time.
399 				 */
400 				n = 1 + (0-t2.tv_sec)/SUPPLY_INTERVAL;
401 				next_bcast.tv_sec += n*SUPPLY_INTERVAL;
402 
403 				continue;
404 			}
405 
406 			if (timercmp(&t2, &wtime, <))
407 				wtime = t2;
408 		}
409 
410 		/* If we need a flash update, either do it now or
411 		 * set the delay to end when it is time.
412 		 *
413 		 * If we are within MIN_WAITTIME seconds of a full update,
414 		 * do not bother.
415 		 */
416 		if (need_flash
417 		    && supplier
418 		    && no_flash.tv_sec+MIN_WAITTIME < next_bcast.tv_sec) {
419 			/* accurate to the millisecond */
420 			if (!timercmp(&no_flash, &now, >))
421 				rip_bcast(1);
422 			timevalsub(&t2, &no_flash, &now);
423 			if (timercmp(&t2, &wtime, <))
424 				wtime = t2;
425 		}
426 
427 		/* trigger the main aging timer.
428 		 */
429 		timevalsub(&t2, &age_timer, &now);
430 		if (t2.tv_sec <= 0) {
431 			age(0);
432 			continue;
433 		}
434 		if (timercmp(&t2, &wtime, <))
435 			wtime = t2;
436 
437 		/* update the kernel routing table
438 		 */
439 		timevalsub(&t2, &need_kern, &now);
440 		if (t2.tv_sec <= 0) {
441 			age(0);
442 			continue;
443 		}
444 		if (timercmp(&t2, &wtime, <))
445 			wtime = t2;
446 
447 		/* take care of router discovery,
448 		 * but do it to the millisecond
449 		 */
450 		if (!timercmp(&rdisc_timer, &now, >)) {
451 			rdisc_age(0);
452 			continue;
453 		}
454 		timevalsub(&t2, &rdisc_timer, &now);
455 		if (timercmp(&t2, &wtime, <))
456 			wtime = t2;
457 
458 
459 		/* wait for input or a timer to expire.
460 		 */
461 		trace_flush();
462 		ibits = fdbits;
463 		n = select(sock_max, &ibits, 0, 0, &wtime);
464 		if (n <= 0) {
465 			if (n < 0 && errno != EINTR && errno != EAGAIN)
466 				BADERR(1,"select");
467 			continue;
468 		}
469 
470 		if (FD_ISSET(rt_sock, &ibits)) {
471 			read_rt();
472 			n--;
473 		}
474 		if (rdisc_sock >= 0 && FD_ISSET(rdisc_sock, &ibits)) {
475 			read_d();
476 			n--;
477 		}
478 		if (rip_sock >= 0 && FD_ISSET(rip_sock, &ibits)) {
479 			read_rip(rip_sock, 0);
480 			n--;
481 		}
482 
483 		for (ifp = ifnet; n > 0 && 0 != ifp; ifp = ifp->int_next) {
484 			if (ifp->int_rip_sock >= 0
485 			    && FD_ISSET(ifp->int_rip_sock, &ibits)) {
486 				read_rip(ifp->int_rip_sock, ifp);
487 				n--;
488 			}
489 		}
490 	}
491 }
492 
493 
494 /* ARGSUSED */
495 void
496 sigalrm(int sig)
497 {
498 	/* Historically, SIGALRM would cause the daemon to check for
499 	 * new and broken interfaces.
500 	 */
501 	ifinit_timer.tv_sec = now.tv_sec;
502 	trace_act("SIGALRM\n");
503 }
504 
505 
506 /* watch for fatal signals */
507 void
508 sigterm(int sig)
509 {
510 	stopint = sig;
511 	(void)signal(sig, SIG_DFL);	/* catch it only once */
512 }
513 
514 
515 void
516 fix_select(void)
517 {
518 	struct interface *ifp;
519 
520 
521 	FD_ZERO(&fdbits);
522 	sock_max = 0;
523 
524 	FD_SET(rt_sock, &fdbits);
525 	if (sock_max <= rt_sock)
526 		sock_max = rt_sock+1;
527 	if (rip_sock >= 0) {
528 		FD_SET(rip_sock, &fdbits);
529 		if (sock_max <= rip_sock)
530 			sock_max = rip_sock+1;
531 	}
532 	for (ifp = ifnet; 0 != ifp; ifp = ifp->int_next) {
533 		if (ifp->int_rip_sock >= 0) {
534 			FD_SET(ifp->int_rip_sock, &fdbits);
535 			if (sock_max <= ifp->int_rip_sock)
536 				sock_max = ifp->int_rip_sock+1;
537 		}
538 	}
539 	if (rdisc_sock >= 0) {
540 		FD_SET(rdisc_sock, &fdbits);
541 		if (sock_max <= rdisc_sock)
542 			sock_max = rdisc_sock+1;
543 	}
544 }
545 
546 
547 void
548 fix_sock(int sock,
549 	 char *name)
550 {
551 	int on;
552 #define MIN_SOCKBUF (4*1024)
553 	static int rbuf;
554 
555 	if (fcntl(sock, F_SETFL, O_NONBLOCK) == -1)
556 		logbad(1, "fcntl(%s) O_NONBLOCK: %s",
557 		       name, strerror(errno));
558 	on = 1;
559 	if (setsockopt(sock, SOL_SOCKET,SO_BROADCAST,
560 		       &on,sizeof(on)) < 0)
561 		msglog("setsockopt(%s,SO_BROADCAST): %s",
562 		       name, strerror(errno));
563 	if (rbuf >= MIN_SOCKBUF) {
564 		if (setsockopt(sock, SOL_SOCKET, SO_RCVBUF,
565 			       &rbuf, sizeof(rbuf)) < 0)
566 			msglog("setsockopt(%s,SO_RCVBUF=%d): %s",
567 			       name, rbuf, strerror(errno));
568 	} else {
569 		for (rbuf = 60*1024; ; rbuf -= 4096) {
570 			if (setsockopt(sock, SOL_SOCKET, SO_RCVBUF,
571 				       &rbuf, sizeof(rbuf)) == 0) {
572 				trace_act("RCVBUF=%d\n", rbuf);
573 				break;
574 			}
575 			if (rbuf < MIN_SOCKBUF) {
576 				msglog("setsockopt(%s,SO_RCVBUF = %d): %s",
577 				       name, rbuf, strerror(errno));
578 				break;
579 			}
580 		}
581 	}
582 }
583 
584 
585 /* get a rip socket
586  */
587 static int				/* <0 or file descriptor */
588 get_rip_sock(naddr addr,
589 	     int serious)		/* 1=failure to bind is serious */
590 {
591 	struct sockaddr_in sin;
592 	unsigned char ttl;
593 	int s;
594 
595 
596 	if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
597 		BADERR(1,"rip_sock = socket()");
598 
599 	bzero(&sin,sizeof(sin));
600 #ifdef _HAVE_SIN_LEN
601 	sin.sin_len = sizeof(sin);
602 #endif
603 	sin.sin_family = AF_INET;
604 	sin.sin_port = htons(RIP_PORT);
605 	sin.sin_addr.s_addr = addr;
606 	if (bind(s, (struct sockaddr *)&sin,sizeof(sin)) < 0) {
607 		if (serious)
608 			BADERR(errno != EADDRINUSE, "bind(rip_sock)");
609 		return -1;
610 	}
611 	fix_sock(s,"rip_sock");
612 
613 	ttl = 1;
614 	if (setsockopt(s, IPPROTO_IP, IP_MULTICAST_TTL,
615 		       &ttl, sizeof(ttl)) < 0)
616 		DBGERR(1,"rip_sock setsockopt(IP_MULTICAST_TTL)");
617 
618 	return s;
619 }
620 
621 
622 /* turn off main RIP socket */
623 void
624 rip_off(void)
625 {
626 	struct interface *ifp;
627 	register naddr addr;
628 
629 
630 	if (rip_sock >= 0 && !mhome) {
631 		trace_act("turn off RIP\n");
632 
633 		(void)close(rip_sock);
634 		rip_sock = -1;
635 
636 		/* get non-broadcast sockets to listen to queries.
637 		 */
638 		for (ifp = ifnet; ifp != 0; ifp = ifp->int_next) {
639 			if (ifp->int_rip_sock < 0
640 			    && !(ifp->int_state & IS_ALIAS)) {
641 				addr = ((ifp->int_if_flags & IFF_POINTOPOINT)
642 					? ifp->int_dstaddr
643 					: ifp->int_addr);
644 				ifp->int_rip_sock = get_rip_sock(addr, 0);
645 			}
646 		}
647 
648 		fix_select();
649 
650 		age(0);
651 	}
652 }
653 
654 
655 /* turn on RIP multicast input via an interface
656  */
657 static void
658 rip_mcast_on(struct interface *ifp)
659 {
660 	struct ip_mreq m;
661 
662 	if (!IS_RIP_IN_OFF(ifp->int_state)
663 	    && (ifp->int_if_flags & IFF_MULTICAST)
664 #ifdef MCAST_PPP_BUG
665 	    && !(ifp->int_if_flags & IFF_POINTOPOINT)
666 #endif
667 	    && !(ifp->int_state & IS_ALIAS)) {
668 		m.imr_multiaddr.s_addr = htonl(INADDR_RIP_GROUP);
669 		m.imr_interface.s_addr = ((ifp->int_if_flags & IFF_POINTOPOINT)
670 					  ? ifp->int_dstaddr
671 					  : ifp->int_addr);
672 		if (setsockopt(rip_sock,IPPROTO_IP, IP_ADD_MEMBERSHIP,
673 			       &m, sizeof(m)) < 0)
674 			LOGERR("setsockopt(IP_ADD_MEMBERSHIP RIP)");
675 	}
676 }
677 
678 
679 /* Prepare socket used for RIP.
680  */
681 void
682 rip_on(struct interface *ifp)
683 {
684 	/* If the main RIP socket is already alive, only start receiving
685 	 * multicasts for this interface.
686 	 */
687 	if (rip_sock >= 0) {
688 		if (ifp != 0)
689 			rip_mcast_on(ifp);
690 		return;
691 	}
692 
693 	/* If the main RIP socket is off, and it makes sense to turn it on,
694 	 * turn it on for all of the interfaces.
695 	 */
696 	if (rip_interfaces > 0 && !rdisc_ok) {
697 		trace_act("turn on RIP\n");
698 
699 		/* Close all of the query sockets so that we can open
700 		 * the main socket.  SO_REUSEPORT is not a solution,
701 		 * since that would let two daemons bind to the broadcast
702 		 * socket.
703 		 */
704 		for (ifp = ifnet; ifp != 0; ifp = ifp->int_next) {
705 			if (ifp->int_rip_sock >= 0) {
706 				(void)close(ifp->int_rip_sock);
707 				ifp->int_rip_sock = -1;
708 			}
709 		}
710 
711 		rip_sock = get_rip_sock(INADDR_ANY, 1);
712 		rip_sock_mcast = 0;
713 
714 		/* Do not advertise anything until we have heard something
715 		 */
716 		if (next_bcast.tv_sec < now.tv_sec+MIN_WAITTIME)
717 			next_bcast.tv_sec = now.tv_sec+MIN_WAITTIME;
718 
719 		for (ifp = ifnet; ifp != 0; ifp = ifp->int_next) {
720 			if (!IS_RIP_IN_OFF(ifp->int_state))
721 				ifp->int_state &= ~IS_RIP_QUERIED;
722 			rip_mcast_on(ifp);
723 		}
724 
725 		ifinit_timer.tv_sec = now.tv_sec;
726 
727 		fix_select();
728 
729 	} else if (ifp != 0
730 		   && ifp->int_rip_sock < 0
731 		   && !(ifp->int_state & IS_ALIAS)) {
732 		/* RIP is off, so ensure there are sockets on which
733 		 * to listen for queries.
734 		 */
735 		ifp->int_rip_sock = get_rip_sock(ifp->int_addr, 0);
736 
737 		fix_select();
738 	}
739 }
740 
741 
742 /* get a random instant in an interval
743  */
744 void
745 intvl_random(struct timeval *tp,	/* put value here */
746 	     u_long lo,			/* value is after this second */
747 	     u_long hi)			/* and before this */
748 {
749 	tp->tv_sec = (time_t)(hi == lo
750 			      ? lo
751 			      : (lo + random() % ((hi - lo))));
752 	tp->tv_usec = random() % 1000000;
753 }
754 
755 
756 void
757 timevaladd(struct timeval *t1,
758 	   struct timeval *t2)
759 {
760 
761 	t1->tv_sec += t2->tv_sec;
762 	if ((t1->tv_usec += t2->tv_usec) > 1000000) {
763 		t1->tv_sec++;
764 		t1->tv_usec -= 1000000;
765 	}
766 }
767 
768 
769 /* t1 = t2 - t3
770  */
771 static void
772 timevalsub(struct timeval *t1,
773 	   struct timeval *t2,
774 	   struct timeval *t3)
775 {
776 	t1->tv_sec = t2->tv_sec - t3->tv_sec;
777 	if ((t1->tv_usec = t2->tv_usec - t3->tv_usec) < 0) {
778 		t1->tv_sec--;
779 		t1->tv_usec += 1000000;
780 	}
781 }
782 
783 
784 void
785 msglog(char *p, ...)
786 {
787 	va_list args;
788 
789 	trace_flush();
790 
791 	va_start(args, p);
792 	vsyslog(LOG_ERR, p, args);
793 
794 	if (ftrace != 0) {
795 		if (ftrace == stdout)
796 			(void)fputs("routed: ", ftrace);
797 		(void)vfprintf(ftrace, p, args);
798 		(void)fputc('\n', ftrace);
799 	}
800 }
801 
802 
803 void
804 logbad(int dump, char *p, ...)
805 {
806 	va_list args;
807 
808 	trace_flush();
809 
810 	va_start(args, p);
811 	vsyslog(LOG_ERR, p, args);
812 
813 	(void)fputs("routed: ", stderr);
814 	(void)vfprintf(stderr, p, args);
815 	(void)fputs("; giving up\n",stderr);
816 	(void)fflush(stderr);
817 
818 	if (dump)
819 		abort();
820 	exit(1);
821 }
822