xref: /freebsd/sbin/routed/main.c (revision cab6a39d7b343596a5823e65c0f7b426551ec22d)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
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. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  *
31  * $FreeBSD$
32  */
33 
34 #include "defs.h"
35 #include "pathnames.h"
36 #include <signal.h>
37 #include <fcntl.h>
38 #include <sys/file.h>
39 
40 __COPYRIGHT("@(#) Copyright (c) 1983, 1988, 1993 "
41 	    "The Regents of the University of California."
42 	    "  All rights reserved.");
43 __RCSID("$FreeBSD$");
44 
45 pid_t	mypid;
46 
47 naddr	myaddr;				/* system address */
48 static char myname[MAXHOSTNAMELEN+1];
49 
50 static int verbose;
51 
52 int	supplier;			/* supply or broadcast updates */
53 int	supplier_set;
54 static int ipforwarding = 1;		/* kernel forwarding on */
55 
56 static int default_gateway;		/* 1=advertise default */
57 static int background = 1;
58 int	ridhosts;			/* 1=reduce host routes */
59 int	mhome;				/* 1=want multi-homed host route */
60 int	advertise_mhome;		/* 1=must continue advertising it */
61 int	auth_ok = 1;			/* 1=ignore auth if we do not care */
62 int	insecure;			/* Reply to special queries or not */
63 
64 struct timeval epoch;			/* when started */
65 struct timeval clk;
66 static struct timeval prev_clk;
67 static int usec_fudge;
68 struct timeval now;			/* current idea of time */
69 time_t	now_stale;
70 time_t	now_expire;
71 time_t	now_garbage;
72 
73 static struct timeval next_bcast;	/* next general broadcast */
74 struct timeval no_flash = {		/* inhibit flash update */
75 	EPOCH+SUPPLY_INTERVAL, 0
76 };
77 
78 static struct timeval flush_kern_timer;
79 
80 static fd_set fdbits;
81 static int sock_max;
82 int	rip_sock = -1;			/* RIP socket */
83 const struct interface *rip_sock_mcast;	/* current multicast interface */
84 int	rt_sock;			/* routing socket */
85 int	rt_sock_seqno;
86 
87 
88 static  int get_rip_sock(naddr, int);
89 static void timevalsub(struct timeval *, struct timeval *, struct timeval *);
90 static void sigalrm(int s UNUSED);
91 static void sigterm(int sig);
92 
93 int
94 main(int argc,
95      char *argv[])
96 {
97 	int n, mib[4], off;
98 	size_t len;
99 	char *p, *q;
100 	const char *cp;
101 	struct timeval wtime, t2;
102 	time_t dt;
103 	fd_set ibits;
104 	naddr p_net, p_mask;
105 	struct interface *ifp;
106 	struct parm parm;
107 	char *tracename = 0;
108 
109 
110 	/* Some shells are badly broken and send SIGHUP to backgrounded
111 	 * processes.
112 	 */
113 	signal(SIGHUP, SIG_IGN);
114 
115 	openlog("routed", LOG_PID, LOG_DAEMON);
116 	ftrace = stdout;
117 
118 	gettimeofday(&clk, 0);
119 	prev_clk = clk;
120 	epoch = clk;
121 	epoch.tv_sec -= EPOCH;
122 	now.tv_sec = EPOCH;
123 	now_stale = EPOCH - STALE_TIME;
124 	now_expire = EPOCH - EXPIRE_TIME;
125 	now_garbage = EPOCH - GARBAGE_TIME;
126 	wtime.tv_sec = 0;
127 
128 	(void)gethostname(myname, sizeof(myname)-1);
129 	(void)gethost(myname, &myaddr);
130 
131 	while ((n = getopt(argc, argv, "isqdghmAtvT:F:P:")) != -1) {
132 		switch (n) {
133 		case 'i':
134 			insecure++;
135 			break;
136 		case 's':
137 			supplier = 1;
138 			supplier_set = 1;
139 			break;
140 
141 		case 'q':
142 			supplier = 0;
143 			supplier_set = 1;
144 			break;
145 
146 		case 'd':
147 			background = 0;
148 			break;
149 
150 		case 'g':
151 			memset(&parm, 0, sizeof(parm));
152 			parm.parm_d_metric = 1;
153 			cp = check_parms(&parm);
154 			if (cp != 0)
155 				msglog("bad -g: %s", cp);
156 			else
157 				default_gateway = 1;
158 			break;
159 
160 		case 'h':		/* suppress extra host routes */
161 			ridhosts = 1;
162 			break;
163 
164 		case 'm':		/* advertise host route */
165 			mhome = 1;	/* on multi-homed hosts */
166 			break;
167 
168 		case 'A':
169 			/* Ignore authentication if we do not care.
170 			 * Crazy as it is, that is what RFC 1723 requires.
171 			 */
172 			auth_ok = 0;
173 			break;
174 
175 		case 't':
176 			new_tracelevel++;
177 			break;
178 
179 		case 'T':
180 			tracename = optarg;
181 			break;
182 
183 		case 'F':		/* minimal routes for SLIP */
184 			n = FAKE_METRIC;
185 			p = strchr(optarg,',');
186 			if (p && *p != '\0') {
187 				n = (int)strtoul(p+1, &q, 0);
188 				if (*q == '\0'
189 				    && n <= HOPCNT_INFINITY-1
190 				    && n >= 1)
191 					*p = '\0';
192 			}
193 			if (!getnet(optarg, &p_net, &p_mask)) {
194 				msglog("bad network; \"-F %s\"",
195 				       optarg);
196 				break;
197 			}
198 			memset(&parm, 0, sizeof(parm));
199 			parm.parm_net = p_net;
200 			parm.parm_mask = p_mask;
201 			parm.parm_d_metric = n;
202 			cp = check_parms(&parm);
203 			if (cp != 0)
204 				msglog("bad -F: %s", cp);
205 			break;
206 
207 		case 'P':
208 			/* handle arbitrary parameters.
209 			 */
210 			q = strdup(optarg);
211 			cp = parse_parms(q, 0);
212 			if (cp != 0)
213 				msglog("%s in \"-P %s\"", cp, optarg);
214 			free(q);
215 			break;
216 
217 		case 'v':
218 			/* display version */
219 			verbose++;
220 			msglog("version 2.31");
221 			break;
222 
223 		default:
224 			goto usage;
225 		}
226 	}
227 	argc -= optind;
228 	argv += optind;
229 
230 	if (tracename == 0 && argc >= 1) {
231 		tracename = *argv++;
232 		argc--;
233 	}
234 	if (tracename != 0 && tracename[0] == '\0')
235 		goto usage;
236 	if (argc != 0) {
237 usage:
238 		logbad(0, "usage: routed [-sqdghmAtv] [-T tracefile]"
239 		       " [-F net[,metric]] [-P parms]");
240 	}
241 	if (geteuid() != 0) {
242 		if (verbose)
243 			exit(0);
244 		logbad(0, "requires UID 0");
245 	}
246 
247 	mib[0] = CTL_NET;
248 	mib[1] = PF_INET;
249 	mib[2] = IPPROTO_IP;
250 	mib[3] = IPCTL_FORWARDING;
251 	len = sizeof(ipforwarding);
252 	if (sysctl(mib, 4, &ipforwarding, &len, 0, 0) < 0)
253 		LOGERR("sysctl(IPCTL_FORWARDING)");
254 
255 	if (!ipforwarding) {
256 		if (supplier)
257 			msglog("-s incompatible with ipforwarding=0");
258 		if (default_gateway) {
259 			msglog("-g incompatible with ipforwarding=0");
260 			default_gateway = 0;
261 		}
262 		supplier = 0;
263 		supplier_set = 1;
264 	}
265 	if (default_gateway) {
266 		if (supplier_set && !supplier) {
267 			msglog("-g and -q incompatible");
268 		} else {
269 			supplier = 1;
270 			supplier_set = 1;
271 		}
272 	}
273 
274 
275 	signal(SIGALRM, sigalrm);
276 	if (!background)
277 		signal(SIGHUP, sigterm);    /* SIGHUP fatal during debugging */
278 	signal(SIGTERM, sigterm);
279 	signal(SIGINT, sigterm);
280 	signal(SIGUSR1, sigtrace_on);
281 	signal(SIGUSR2, sigtrace_off);
282 
283 	/* get into the background */
284 	if (background && daemon(0, 1) < 0)
285 		BADERR(0,"daemon()");
286 
287 	mypid = getpid();
288 
289 	/* prepare socket connected to the kernel.
290 	 */
291 	rt_sock = socket(AF_ROUTE, SOCK_RAW, 0);
292 	if (rt_sock < 0)
293 		BADERR(1,"rt_sock = socket()");
294 	if (fcntl(rt_sock, F_SETFL, O_NONBLOCK) == -1)
295 		logbad(1, "fcntl(rt_sock) O_NONBLOCK: %s", strerror(errno));
296 	off = 0;
297 	if (setsockopt(rt_sock, SOL_SOCKET,SO_USELOOPBACK,
298 		       &off,sizeof(off)) < 0)
299 		LOGERR("setsockopt(SO_USELOOPBACK,0)");
300 
301 	fix_select();
302 
303 
304 	if (tracename != 0) {
305 		strncpy(inittracename, tracename, sizeof(inittracename)-1);
306 		set_tracefile(inittracename, "%s", -1);
307 	} else {
308 		tracelevel_msg("%s", -1);   /* turn on tracing to stdio */
309 	}
310 
311 	bufinit();
312 
313 	/* initialize radix tree */
314 	rtinit();
315 
316 	/* Pick a random part of the second for our output to minimize
317 	 * collisions.
318 	 *
319 	 * Start broadcasting after hearing from other routers, and
320 	 * at a random time so a bunch of systems do not get synchronized
321 	 * after a power failure.
322 	 */
323 	intvl_random(&next_bcast, EPOCH+MIN_WAITTIME, EPOCH+SUPPLY_INTERVAL);
324 	age_timer.tv_usec = next_bcast.tv_usec;
325 	age_timer.tv_sec = EPOCH+MIN_WAITTIME;
326 	rdisc_timer = next_bcast;
327 	ifinit_timer.tv_usec = next_bcast.tv_usec;
328 
329 	/* Collect an initial view of the world by checking the interface
330 	 * configuration and the kludge file.
331 	 */
332 	gwkludge();
333 	ifinit();
334 
335 	/* Ask for routes */
336 	rip_query();
337 	rdisc_sol();
338 
339 	/* Now turn off stdio if not tracing */
340 	if (new_tracelevel == 0)
341 		trace_close(background);
342 
343 	/* Loop forever, listening and broadcasting.
344 	 */
345 	for (;;) {
346 		prev_clk = clk;
347 		gettimeofday(&clk, 0);
348 		if (prev_clk.tv_sec == clk.tv_sec
349 		    && prev_clk.tv_usec == clk.tv_usec+usec_fudge) {
350 			/* Much of `routed` depends on time always advancing.
351 			 * On systems that do not guarantee that gettimeofday()
352 			 * produces unique timestamps even if called within
353 			 * a single tick, use trickery like that in classic
354 			 * BSD kernels.
355 			 */
356 			clk.tv_usec += ++usec_fudge;
357 
358 		} else {
359 			usec_fudge = 0;
360 
361 			timevalsub(&t2, &clk, &prev_clk);
362 			if (t2.tv_sec < 0
363 			    || t2.tv_sec > wtime.tv_sec + 5) {
364 				/* Deal with time changes before other
365 				 * housekeeping to keep everything straight.
366 				 */
367 				dt = t2.tv_sec;
368 				if (dt > 0)
369 					dt -= wtime.tv_sec;
370 				trace_act("time changed by %d sec", (int)dt);
371 				epoch.tv_sec += dt;
372 			}
373 		}
374 		timevalsub(&now, &clk, &epoch);
375 		now_stale = now.tv_sec - STALE_TIME;
376 		now_expire = now.tv_sec - EXPIRE_TIME;
377 		now_garbage = now.tv_sec - GARBAGE_TIME;
378 
379 		/* deal with signals that should affect tracing */
380 		set_tracelevel();
381 
382 		if (stopint != 0) {
383 			rip_bcast(0);
384 			rdisc_adv();
385 			trace_off("exiting with signal %d", stopint);
386 			exit(stopint | 128);
387 		}
388 
389 		/* look for new or dead interfaces */
390 		timevalsub(&wtime, &ifinit_timer, &now);
391 		if (wtime.tv_sec <= 0) {
392 			wtime.tv_sec = 0;
393 			ifinit();
394 			rip_query();
395 			continue;
396 		}
397 
398 		/* Check the kernel table occasionally for mysteriously
399 		 * evaporated routes
400 		 */
401 		timevalsub(&t2, &flush_kern_timer, &now);
402 		if (t2.tv_sec <= 0) {
403 			flush_kern();
404 			flush_kern_timer.tv_sec = (now.tv_sec
405 						   + CHECK_QUIET_INTERVAL);
406 			continue;
407 		}
408 		if (timercmp(&t2, &wtime, <))
409 			wtime = t2;
410 
411 		/* If it is time, then broadcast our routes.
412 		 */
413 		if (supplier || advertise_mhome) {
414 			timevalsub(&t2, &next_bcast, &now);
415 			if (t2.tv_sec <= 0) {
416 				/* Synchronize the aging and broadcast
417 				 * timers to minimize awakenings
418 				 */
419 				age(0);
420 
421 				rip_bcast(0);
422 
423 				/* It is desirable to send routing updates
424 				 * regularly.  So schedule the next update
425 				 * 30 seconds after the previous one was
426 				 * scheduled, instead of 30 seconds after
427 				 * the previous update was finished.
428 				 * Even if we just started after discovering
429 				 * a 2nd interface or were otherwise delayed,
430 				 * pick a 30-second anniversary of the
431 				 * original broadcast time.
432 				 */
433 				n = 1 + (0-t2.tv_sec)/SUPPLY_INTERVAL;
434 				next_bcast.tv_sec += n*SUPPLY_INTERVAL;
435 
436 				continue;
437 			}
438 
439 			if (timercmp(&t2, &wtime, <))
440 				wtime = t2;
441 		}
442 
443 		/* If we need a flash update, either do it now or
444 		 * set the delay to end when it is time.
445 		 *
446 		 * If we are within MIN_WAITTIME seconds of a full update,
447 		 * do not bother.
448 		 */
449 		if (need_flash
450 		    && supplier
451 		    && no_flash.tv_sec+MIN_WAITTIME < next_bcast.tv_sec) {
452 			/* accurate to the millisecond */
453 			if (!timercmp(&no_flash, &now, >))
454 				rip_bcast(1);
455 			timevalsub(&t2, &no_flash, &now);
456 			if (timercmp(&t2, &wtime, <))
457 				wtime = t2;
458 		}
459 
460 		/* trigger the main aging timer.
461 		 */
462 		timevalsub(&t2, &age_timer, &now);
463 		if (t2.tv_sec <= 0) {
464 			age(0);
465 			continue;
466 		}
467 		if (timercmp(&t2, &wtime, <))
468 			wtime = t2;
469 
470 		/* update the kernel routing table
471 		 */
472 		timevalsub(&t2, &need_kern, &now);
473 		if (t2.tv_sec <= 0) {
474 			age(0);
475 			continue;
476 		}
477 		if (timercmp(&t2, &wtime, <))
478 			wtime = t2;
479 
480 		/* take care of router discovery,
481 		 * but do it in the correct the millisecond
482 		 */
483 		if (!timercmp(&rdisc_timer, &now, >)) {
484 			rdisc_age(0);
485 			continue;
486 		}
487 		timevalsub(&t2, &rdisc_timer, &now);
488 		if (timercmp(&t2, &wtime, <))
489 			wtime = t2;
490 
491 
492 		/* wait for input or a timer to expire.
493 		 */
494 		trace_flush();
495 		ibits = fdbits;
496 		n = select(sock_max, &ibits, 0, 0, &wtime);
497 		if (n <= 0) {
498 			if (n < 0 && errno != EINTR && errno != EAGAIN)
499 				BADERR(1,"select");
500 			continue;
501 		}
502 
503 		if (FD_ISSET(rt_sock, &ibits)) {
504 			read_rt();
505 			n--;
506 		}
507 		if (rdisc_sock >= 0 && FD_ISSET(rdisc_sock, &ibits)) {
508 			read_d();
509 			n--;
510 		}
511 		if (rip_sock >= 0 && FD_ISSET(rip_sock, &ibits)) {
512 			read_rip(rip_sock, 0);
513 			n--;
514 		}
515 
516 		LIST_FOREACH(ifp, &ifnet, int_list) {
517 			if (n <= 0)
518 				break;
519 			if (ifp->int_rip_sock >= 0
520 			    && FD_ISSET(ifp->int_rip_sock, &ibits)) {
521 				read_rip(ifp->int_rip_sock, ifp);
522 				n--;
523 			}
524 		}
525 	}
526 }
527 
528 
529 /* ARGSUSED */
530 static void
531 sigalrm(int s UNUSED)
532 {
533 	/* Historically, SIGALRM would cause the daemon to check for
534 	 * new and broken interfaces.
535 	 */
536 	ifinit_timer.tv_sec = now.tv_sec;
537 	trace_act("SIGALRM");
538 }
539 
540 
541 /* watch for fatal signals */
542 static void
543 sigterm(int sig)
544 {
545 	stopint = sig;
546 	(void)signal(sig, SIG_DFL);	/* catch it only once */
547 }
548 
549 
550 void
551 fix_select(void)
552 {
553 	struct interface *ifp;
554 
555 
556 	FD_ZERO(&fdbits);
557 	sock_max = 0;
558 
559 	FD_SET(rt_sock, &fdbits);
560 	if (sock_max <= rt_sock)
561 		sock_max = rt_sock+1;
562 	if (rip_sock >= 0) {
563 		FD_SET(rip_sock, &fdbits);
564 		if (sock_max <= rip_sock)
565 			sock_max = rip_sock+1;
566 	}
567 	LIST_FOREACH(ifp, &ifnet, int_list) {
568 		if (ifp->int_rip_sock >= 0) {
569 			FD_SET(ifp->int_rip_sock, &fdbits);
570 			if (sock_max <= ifp->int_rip_sock)
571 				sock_max = ifp->int_rip_sock+1;
572 		}
573 	}
574 	if (rdisc_sock >= 0) {
575 		FD_SET(rdisc_sock, &fdbits);
576 		if (sock_max <= rdisc_sock)
577 			sock_max = rdisc_sock+1;
578 	}
579 }
580 
581 
582 void
583 fix_sock(int sock,
584 	 const char *name)
585 {
586 	int on;
587 #define MIN_SOCKBUF (4*1024)
588 	static int rbuf;
589 
590 	if (fcntl(sock, F_SETFL, O_NONBLOCK) == -1)
591 		logbad(1, "fcntl(%s) O_NONBLOCK: %s",
592 		       name, strerror(errno));
593 	on = 1;
594 	if (setsockopt(sock, SOL_SOCKET,SO_BROADCAST, &on,sizeof(on)) < 0)
595 		msglog("setsockopt(%s,SO_BROADCAST): %s",
596 		       name, strerror(errno));
597 #ifdef USE_PASSIFNAME
598 	on = 1;
599 	if (setsockopt(sock, SOL_SOCKET, SO_PASSIFNAME, &on,sizeof(on)) < 0)
600 		msglog("setsockopt(%s,SO_PASSIFNAME): %s",
601 		       name, strerror(errno));
602 #endif
603 
604 	if (rbuf >= MIN_SOCKBUF) {
605 		if (setsockopt(sock, SOL_SOCKET, SO_RCVBUF,
606 			       &rbuf, sizeof(rbuf)) < 0)
607 			msglog("setsockopt(%s,SO_RCVBUF=%d): %s",
608 			       name, rbuf, strerror(errno));
609 	} else {
610 		for (rbuf = 60*1024; ; rbuf -= 4096) {
611 			if (setsockopt(sock, SOL_SOCKET, SO_RCVBUF,
612 				       &rbuf, sizeof(rbuf)) == 0) {
613 				trace_act("RCVBUF=%d", rbuf);
614 				break;
615 			}
616 			if (rbuf < MIN_SOCKBUF) {
617 				msglog("setsockopt(%s,SO_RCVBUF = %d): %s",
618 				       name, rbuf, strerror(errno));
619 				break;
620 			}
621 		}
622 	}
623 }
624 
625 
626 /* get a rip socket
627  */
628 static int				/* <0 or file descriptor */
629 get_rip_sock(naddr addr,
630 	     int serious)		/* 1=failure to bind is serious */
631 {
632 	struct sockaddr_in rsin;
633 	unsigned char ttl;
634 	int s;
635 
636 
637 	if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
638 		BADERR(1,"rip_sock = socket()");
639 
640 	memset(&rsin, 0, sizeof(rsin));
641 #ifdef _HAVE_SIN_LEN
642 	rsin.sin_len = sizeof(rsin);
643 #endif
644 	rsin.sin_family = AF_INET;
645 	rsin.sin_port = htons(RIP_PORT);
646 	rsin.sin_addr.s_addr = addr;
647 	if (bind(s, (struct sockaddr *)&rsin, sizeof(rsin)) < 0) {
648 		if (serious)
649 			BADERR(errno != EADDRINUSE, "bind(rip_sock)");
650 		close(s);
651 		return -1;
652 	}
653 	fix_sock(s,"rip_sock");
654 
655 	ttl = 1;
656 	if (setsockopt(s, IPPROTO_IP, IP_MULTICAST_TTL,
657 		       &ttl, sizeof(ttl)) < 0)
658 		DBGERR(1,"rip_sock setsockopt(IP_MULTICAST_TTL)");
659 
660 	return s;
661 }
662 
663 
664 /* turn off main RIP socket */
665 void
666 rip_off(void)
667 {
668 	struct interface *ifp;
669 	naddr addr;
670 
671 
672 	if (rip_sock >= 0 && !mhome) {
673 		trace_act("turn off RIP");
674 
675 		(void)close(rip_sock);
676 		rip_sock = -1;
677 
678 		/* get non-broadcast sockets to listen to queries.
679 		 */
680 		LIST_FOREACH(ifp, &ifnet, int_list) {
681 			if (ifp->int_state & IS_REMOTE)
682 				continue;
683 			if (ifp->int_rip_sock < 0) {
684 				addr = ((ifp->int_if_flags & IFF_POINTOPOINT)
685 					? ifp->int_dstaddr
686 					: ifp->int_addr);
687 				ifp->int_rip_sock = get_rip_sock(addr, 0);
688 			}
689 		}
690 
691 		fix_select();
692 
693 		age(0);
694 	}
695 }
696 
697 
698 /* turn on RIP multicast input via an interface
699  */
700 static void
701 rip_mcast_on(struct interface *ifp)
702 {
703 	struct group_req gr;
704 	struct sockaddr_in *sin;
705 
706 	if (!IS_RIP_IN_OFF(ifp->int_state)
707 	    && (ifp->int_if_flags & IFF_MULTICAST)
708 	    && !(ifp->int_state & IS_ALIAS)) {
709 		memset(&gr, 0, sizeof(gr));
710 		gr.gr_interface = ifp->int_index;
711 		sin = (struct sockaddr_in *)&gr.gr_group;
712 		sin->sin_family = AF_INET;
713 #ifdef _HAVE_SIN_LEN
714 		sin->sin_len = sizeof(struct sockaddr_in);
715 #endif
716 		sin->sin_addr.s_addr = htonl(INADDR_RIP_GROUP);
717 		if (setsockopt(rip_sock, IPPROTO_IP, MCAST_JOIN_GROUP,
718 			       &gr, sizeof(gr)) < 0)
719 			LOGERR("setsockopt(MCAST_JOIN_GROUP RIP)");
720 	}
721 }
722 
723 
724 /* Prepare socket used for RIP.
725  */
726 void
727 rip_on(struct interface *ifp)
728 {
729 	/* If the main RIP socket is already alive, only start receiving
730 	 * multicasts for this interface.
731 	 */
732 	if (rip_sock >= 0) {
733 		if (ifp != NULL)
734 			rip_mcast_on(ifp);
735 		return;
736 	}
737 
738 	/* If the main RIP socket is off and it makes sense to turn it on,
739 	 * then turn it on for all of the interfaces.
740 	 * It makes sense if either router discovery is off, or if
741 	 * router discover is on and at most one interface is doing RIP.
742 	 */
743 	if (rip_interfaces > 0 && (!rdisc_ok || rip_interfaces > 1)) {
744 		trace_act("turn on RIP");
745 
746 		/* Close all of the query sockets so that we can open
747 		 * the main socket.  SO_REUSEPORT is not a solution,
748 		 * since that would let two daemons bind to the broadcast
749 		 * socket.
750 		 */
751 		LIST_FOREACH(ifp, &ifnet, int_list) {
752 			if (ifp->int_rip_sock >= 0) {
753 				(void)close(ifp->int_rip_sock);
754 				ifp->int_rip_sock = -1;
755 			}
756 		}
757 
758 		rip_sock = get_rip_sock(INADDR_ANY, 1);
759 		rip_sock_mcast = NULL;
760 
761 		/* Do not advertise anything until we have heard something
762 		 */
763 		if (next_bcast.tv_sec < now.tv_sec+MIN_WAITTIME)
764 			next_bcast.tv_sec = now.tv_sec+MIN_WAITTIME;
765 
766 		LIST_FOREACH(ifp, &ifnet, int_list) {
767 			ifp->int_query_time = NEVER;
768 			rip_mcast_on(ifp);
769 		}
770 		ifinit_timer.tv_sec = now.tv_sec;
771 
772 	} else if (ifp != NULL
773 		   && !(ifp->int_state & IS_REMOTE)
774 		   && ifp->int_rip_sock < 0) {
775 		/* RIP is off, so ensure there are sockets on which
776 		 * to listen for queries.
777 		 */
778 		ifp->int_rip_sock = get_rip_sock(ifp->int_addr, 0);
779 	}
780 
781 	fix_select();
782 }
783 
784 
785 /* die if malloc(3) fails
786  */
787 void *
788 rtmalloc(size_t size,
789 	 const char *msg)
790 {
791 	void *p = malloc(size);
792 	if (p == NULL)
793 		logbad(1,"malloc(%lu) failed in %s", (u_long)size, msg);
794 	return p;
795 }
796 
797 
798 /* get a random instant in an interval
799  */
800 void
801 intvl_random(struct timeval *tp,	/* put value here */
802 	     u_long lo,			/* value is after this second */
803 	     u_long hi)			/* and before this */
804 {
805 	tp->tv_sec = (time_t)(hi == lo
806 			      ? lo
807 			      : (lo + arc4random_uniform(1 + hi - lo)));
808 	tp->tv_usec = arc4random_uniform(1000000);
809 }
810 
811 
812 void
813 timevaladd(struct timeval *t1,
814 	   struct timeval *t2)
815 {
816 
817 	t1->tv_sec += t2->tv_sec;
818 	if ((t1->tv_usec += t2->tv_usec) >= 1000000) {
819 		t1->tv_sec++;
820 		t1->tv_usec -= 1000000;
821 	}
822 }
823 
824 
825 /* t1 = t2 - t3
826  */
827 static void
828 timevalsub(struct timeval *t1,
829 	   struct timeval *t2,
830 	   struct timeval *t3)
831 {
832 	t1->tv_sec = t2->tv_sec - t3->tv_sec;
833 	if ((t1->tv_usec = t2->tv_usec - t3->tv_usec) < 0) {
834 		t1->tv_sec--;
835 		t1->tv_usec += 1000000;
836 	}
837 }
838 
839 
840 /* put a message into the system log
841  */
842 void
843 msglog(const char *p, ...)
844 {
845 	va_list args;
846 
847 	trace_flush();
848 
849 	va_start(args, p);
850 	vsyslog(LOG_ERR, p, args);
851 	va_end(args);
852 	if (ftrace != NULL) {
853 		if (ftrace == stdout)
854 			(void)fputs("routed: ", ftrace);
855 		va_start(args, p);
856 		(void)vfprintf(ftrace, p, args);
857 		va_end(args);
858 		(void)fputc('\n', ftrace);
859 	}
860 }
861 
862 
863 /* Put a message about a bad system into the system log if
864  * we have not complained about it recently.
865  *
866  * It is desirable to complain about all bad systems, but not too often.
867  * In the worst case, it is not practical to keep track of all bad systems.
868  * For example, there can be many systems with the wrong password.
869  */
870 void
871 msglim(struct msg_limit *lim, naddr addr, const char *p, ...)
872 {
873 	va_list args;
874 	int i;
875 	struct msg_sub *ms1, *ms;
876 	const char *p1;
877 
878 	/* look for the oldest slot in the table
879 	 * or the slot for the bad router.
880 	 */
881 	ms = ms1 = lim->subs;
882 	for (i = MSG_SUBJECT_N; ; i--, ms1++) {
883 		if (i == 0) {
884 			/* Reuse a slot at most once every 10 minutes.
885 			 */
886 			if (lim->reuse > now.tv_sec) {
887 				ms = NULL;
888 			} else {
889 				ms = ms1;
890 				lim->reuse = now.tv_sec + 10*60;
891 			}
892 			break;
893 		}
894 		if (ms->addr == addr) {
895 			/* Repeat a complaint about a given system at
896 			 * most once an hour.
897 			 */
898 			if (ms->until > now.tv_sec)
899 				ms = NULL;
900 			break;
901 		}
902 		if (ms->until < ms1->until)
903 			ms = ms1;
904 	}
905 	if (ms != NULL) {
906 		ms->addr = addr;
907 		ms->until = now.tv_sec + 60*60;	/* 60 minutes */
908 
909 		trace_flush();
910 		for (p1 = p; *p1 == ' '; p1++)
911 			continue;
912 		va_start(args, p);
913 		vsyslog(LOG_ERR, p1, args);
914 		va_end(args);
915 	}
916 
917 	/* always display the message if tracing */
918 	if (ftrace != NULL) {
919 		va_start(args, p);
920 		(void)vfprintf(ftrace, p, args);
921 		va_end(args);
922 		(void)fputc('\n', ftrace);
923 	}
924 }
925 
926 
927 void
928 logbad(int dump, const char *p, ...)
929 {
930 	va_list args;
931 
932 	trace_flush();
933 
934 	va_start(args, p);
935 	vsyslog(LOG_ERR, p, args);
936 	va_end(args);
937 	(void)fputs("routed: ", stderr);
938 	va_start(args, p);
939 	(void)vfprintf(stderr, p, args);
940 	va_end(args);
941 	(void)fputs("; giving up\n",stderr);
942 	(void)fflush(stderr);
943 
944 	if (dump)
945 		abort();
946 	exit(1);
947 }
948