xref: /freebsd/usr.sbin/rtsold/rtsold.c (revision daf1cffce2e07931f27c6c6998652e90df6ba87e) 
1 /*
2  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the project nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  * $FreeBSD$
30  */
31 
32 #include <sys/types.h>
33 #include <sys/time.h>
34 
35 #include <net/if_dl.h>
36 
37 #include <netinet/in.h>
38 #include <netinet/icmp6.h>
39 
40 #include <signal.h>
41 #include <unistd.h>
42 #include <syslog.h>
43 #include <string.h>
44 #include <stdlib.h>
45 #include <stdio.h>
46 #include <errno.h>
47 #include <err.h>
48 #include <stdarg.h>
49 #include "rtsold.h"
50 
51 struct ifinfo *iflist;
52 struct timeval tm_max =	{0x7fffffff, 0x7fffffff};
53 int dflag;
54 static int log_upto = 999;
55 static int fflag = 0;
56 
57 /* protocol constatns */
58 #define	MAX_RTR_SOLICITATION_DELAY	1 /* second */
59 #define	RTR_SOLICITATION_INTERVAL	4 /* seconds */
60 #define	MAX_RTR_SOLICITATIONS		3 /* times */
61 
62 /* implementation dependent constants */
63 #define	PROBE_INTERVAL 60	/* secondes XXX: should be configurable */
64 
65 /* utility macros */
66 /* a < b */
67 #define	TIMEVAL_LT(a, b) (((a).tv_sec < (b).tv_sec) ||\
68 			  (((a).tv_sec == (b).tv_sec) && \
69 			    ((a).tv_usec < (b).tv_usec)))
70 
71 /* a <= b */
72 #define	TIMEVAL_LEQ(a, b) (((a).tv_sec < (b).tv_sec) ||\
73 			   (((a).tv_sec == (b).tv_sec) &&\
74  			    ((a).tv_usec <= (b).tv_usec)))
75 
76 /* a == b */
77 #define	TIMEVAL_EQ(a, b) (((a).tv_sec==(b).tv_sec) && ((a).tv_usec==(b).tv_usec))
78 
79 int main __P((int argc, char *argv[]));
80 
81 /* static variables and functions */
82 static int mobile_node = 0;
83 static int do_dump;
84 static char *dumpfilename = "/var/tmp/rtsold.dump"; /* XXX: should be configurable */
85 static char *pidfilename = "/var/run/rtsold.pid"; /* should be configurable */
86 
87 static int ifconfig __P((char *ifname));
88 static int make_packet __P((struct ifinfo *ifinfo));
89 static struct timeval *rtsol_check_timer __P((void));
90 static void TIMEVAL_ADD __P((struct timeval *a, struct timeval *b,
91 			     struct timeval *result));
92 static void TIMEVAL_SUB __P((struct timeval *a, struct timeval *b,
93 			     struct timeval *result));
94 
95 static void rtsold_set_dump_file __P(());
96 static void usage __P((char *progname));
97 
98 int
99 main(argc, argv)
100 	int argc;
101 	char *argv[];
102 {
103 	int s, ch;
104 	int once = 0;
105 	struct timeval *timeout;
106 	struct fd_set fdset;
107 	char *argv0;
108 	char *opts;
109 
110 	/*
111 	 * Initialization
112 	 */
113 	argv0 = argv[0];
114 
115 	/* get option */
116 	if (argv0 && argv0[strlen(argv0) - 1] != 'd') {
117 		fflag = 1;
118 		once = 1;
119 		opts = "dD";
120 	} else
121 		opts = "dDfm1";
122 
123 	while ((ch = getopt(argc, argv, opts)) != -1) {
124 		switch(ch) {
125 		 case 'd':
126 			 dflag = 1;
127 			 break;
128 		 case 'D':
129 			 dflag = 2;
130 			 break;
131 		 case 'f':
132 			 fflag = 1;
133 			 break;
134 		 case 'm':
135 			 mobile_node = 1;
136 			 break;
137 		 case '1':
138 			 once = 1;
139 			 break;
140 		 default:
141 			 usage(argv0);
142 		}
143 	}
144 	argc -= optind;
145 	argv += optind;
146 	if (argc == 0)
147 		usage(argv0);
148 
149 	/* set log level */
150 	if (dflag == 0)
151 		log_upto = LOG_NOTICE;
152 	if (!fflag) {
153 		char *ident;
154 		ident = strrchr(argv0, '/');
155 		if (!ident)
156 			ident = argv0;
157 		else
158 			ident++;
159 		openlog(ident, LOG_NDELAY|LOG_PID, LOG_DAEMON);
160 		if (log_upto >= 0)
161 			setlogmask(LOG_UPTO(log_upto));
162 	}
163 
164 	/* random value initilization */
165 	srandom((u_long)time(NULL));
166 
167 	/* warn if accept_rtadv is down */
168 	if (!getinet6sysctl(IPV6CTL_ACCEPT_RTADV))
169 		warnx("kernel is configured not to accept RAs");
170 
171 	/* initialization to dump internal status to a file */
172 	if (signal(SIGUSR1, (void *)rtsold_set_dump_file) < 0)
173 		errx(1, "failed to set signal for dump status");
174 
175 	/* configuration per interface */
176 	if (ifinit())
177 		errx(1, "failed to initilizatoin interfaces");
178 	while (argc--) {
179 		if (ifconfig(*argv))
180 			errx(1, "failed to initilize %s", *argv);
181 		argv++;
182 	}
183 
184 	/* open a socket for sending RS and receiving RA */
185 	if ((s = sockopen()) < 0)
186 		errx(1, "failed to open a socket");
187 
188 	/* setup for probing default routers */
189 	if (probe_init())
190 		errx(1, "failed to setup for probing routers");
191 
192 	if (!fflag)
193 		daemon(0, 0);		/* act as a daemon */
194 
195 	/* dump the current pid */
196 	if (!once) {
197 		pid_t pid = getpid();
198 		FILE *fp;
199 
200 		if ((fp = fopen(pidfilename, "w")) == NULL)
201 			warnmsg(LOG_ERR, __FUNCTION__,
202 				"failed to open a log file(%s)",
203 				pidfilename, strerror(errno));
204 		else {
205 			fprintf(fp, "%d\n", pid);
206 			fclose(fp);
207 		}
208 	}
209 
210 	FD_ZERO(&fdset);
211 	FD_SET(s, &fdset);
212 	while (1) {		/* main loop */
213 		extern int errno;
214 		int e;
215 		struct fd_set select_fd = fdset;
216 
217 		if (do_dump) {	/* SIGUSR1 */
218 			do_dump = 0;
219 			rtsold_dump_file(dumpfilename);
220 		}
221 
222 		timeout = rtsol_check_timer();
223 
224 		if (once) {
225 			struct ifinfo *ifi;
226 
227 			/* if we have no timeout, we are done (or failed) */
228 			if (timeout == NULL)
229 				break;
230 
231 			/* if all interfaces have got RA packet, we are done */
232 			for (ifi = iflist; ifi; ifi = ifi->next) {
233 				if (ifi->state != IFS_DOWN && ifi->racnt == 0)
234 					break;
235 			}
236 			if (ifi == NULL)
237 				break;
238 		}
239 
240 		if ((e = select(s + 1, &select_fd, NULL, NULL, timeout)) < 1) {
241 			if (e < 0 && errno != EINTR) {
242 				warnmsg(LOG_ERR, __FUNCTION__, "select: %s",
243 				       strerror(errno));
244 			}
245 			continue;
246 		}
247 
248 		/* packet reception */
249 		if (FD_ISSET(s, &fdset))
250 			rtsol_input(s);
251 	}
252 	/* NOTREACHED */
253 
254 	return 0;
255 }
256 
257 static int
258 ifconfig(char *ifname)
259 {
260 	struct ifinfo *ifinfo;
261 	struct sockaddr_dl *sdl;
262 	int flags;
263 
264 	if ((sdl = if_nametosdl(ifname)) == NULL) {
265 		warnmsg(LOG_ERR, __FUNCTION__,
266 		       "failed to get link layer information for %s", ifname);
267 		return(-1);
268 	}
269 	if (find_ifinfo(sdl->sdl_index)) {
270 		warnmsg(LOG_ERR, __FUNCTION__,
271 			"interface %s was already cofigured", ifname);
272 		return(-1);
273 	}
274 
275 	if ((ifinfo = malloc(sizeof(*ifinfo))) == NULL) {
276 		warnmsg(LOG_ERR, __FUNCTION__, "memory allocation failed");
277 		return(-1);
278 	}
279 	memset(ifinfo, 0, sizeof(*ifinfo));
280 	ifinfo->sdl = sdl;
281 
282 	strncpy(ifinfo->ifname, ifname, sizeof(ifinfo->ifname));
283 
284 	/* construct a router solicitation message */
285 	if (make_packet(ifinfo))
286 		goto bad;
287 
288 	/*
289 	 * check if the interface is available.
290 	 * also check if SIOCGIFMEDIA ioctl is OK on the interface.
291 	 */
292 	ifinfo->mediareqok = 1;
293 	ifinfo->active = interface_status(ifinfo);
294 	if (!ifinfo->mediareqok) {
295 		/*
296 		 * probe routers periodically even if the link status
297 		 * does not change.
298 		 */
299 		ifinfo->probeinterval = PROBE_INTERVAL;
300 	}
301 
302 	/* activate interface: interface_up returns 0 on success */
303 	flags = interface_up(ifinfo->ifname);
304 	if (flags == 0)
305 		ifinfo->state = IFS_DELAY;
306 	else if (flags == IFS_TENTATIVE)
307 		ifinfo->state = IFS_TENTATIVE;
308 	else
309 		ifinfo->state = IFS_DOWN;
310 
311 	rtsol_timer_update(ifinfo);
312 
313 	/* link into chain */
314 	if (iflist)
315 		ifinfo->next = iflist;
316 	iflist = ifinfo;
317 
318 	return(0);
319 
320   bad:
321 	free(ifinfo);
322 	free(ifinfo->sdl);
323 	return(-1);
324 }
325 
326 struct ifinfo *
327 find_ifinfo(int ifindex)
328 {
329 	struct ifinfo *ifi;
330 
331 	for (ifi = iflist; ifi; ifi = ifi->next)
332 		if (ifi->sdl->sdl_index == ifindex)
333 			return(ifi);
334 
335 	return(NULL);
336 }
337 
338 static int
339 make_packet(struct ifinfo *ifinfo)
340 {
341 	char *buf;
342 	struct nd_router_solicit *rs;
343 	size_t packlen = sizeof(struct nd_router_solicit), lladdroptlen = 0;
344 
345 	if ((lladdroptlen = lladdropt_length(ifinfo->sdl)) == 0) {
346 		warnmsg(LOG_INFO, __FUNCTION__,
347 			"link-layer address option has null length"
348 		       " on %s. Treat as not included.", ifinfo->ifname);
349 	}
350 	packlen += lladdroptlen;
351 	ifinfo->rs_datalen = packlen;
352 
353 	/* allocate buffer */
354 	if ((buf = malloc(packlen)) == NULL) {
355 		warnmsg(LOG_ERR, __FUNCTION__,
356 			"memory allocation failed for %s", ifinfo->ifname);
357 		return(-1);
358 	}
359 	ifinfo->rs_data = buf;
360 
361 	/* fill in the message */
362 	rs = (struct nd_router_solicit *)buf;
363 	rs->nd_rs_type = ND_ROUTER_SOLICIT;
364 	rs->nd_rs_code = 0;
365 	rs->nd_rs_cksum = 0;
366 	rs->nd_rs_reserved = 0;
367 	buf += sizeof(*rs);
368 
369 	/* fill in source link-layer address option */
370 	if (lladdroptlen)
371 		lladdropt_fill(ifinfo->sdl, (struct nd_opt_hdr *)buf);
372 
373 	return(0);
374 }
375 
376 static struct timeval *
377 rtsol_check_timer()
378 {
379 	static struct timeval returnval;
380 	struct timeval now, rtsol_timer;
381 	struct ifinfo *ifinfo;
382 	int flags;
383 
384 	gettimeofday(&now, NULL);
385 
386 	rtsol_timer = tm_max;
387 
388 	for (ifinfo = iflist; ifinfo; ifinfo = ifinfo->next) {
389 		if (TIMEVAL_LEQ(ifinfo->expire, now)) {
390 			if (dflag > 1)
391 				warnmsg(LOG_DEBUG, __FUNCTION__,
392 					"timer expiration on %s, "
393 				       "state = %d", ifinfo->ifname,
394 				       ifinfo->state);
395 
396 			switch(ifinfo->state) {
397 			case IFS_DOWN:
398 			case IFS_TENTATIVE:
399 				/* interface_up returns 0 on success */
400 				flags = interface_up(ifinfo->ifname);
401 				if (flags == 0)
402 					ifinfo->state = IFS_DELAY;
403 				else if (flags == IFS_TENTATIVE)
404 					ifinfo->state = IFS_TENTATIVE;
405 				else
406 					ifinfo->state = IFS_DOWN;
407 				break;
408 			case IFS_IDLE:
409 			{
410 				int oldstatus = ifinfo->active;
411 				int probe = 0;
412 
413 				ifinfo->active =
414 					interface_status(ifinfo);
415 
416 				if (oldstatus != ifinfo->active) {
417 					warnmsg(LOG_DEBUG, __FUNCTION__,
418 						"%s status is changed"
419 						" from %d to %d",
420 						ifinfo->ifname,
421 						oldstatus, ifinfo->active);
422 					probe = 1;
423 					ifinfo->state = IFS_DELAY;
424 				}
425 				else if (ifinfo->probeinterval &&
426 					 (ifinfo->probetimer -=
427 					  ifinfo->timer.tv_sec) <= 0) {
428 					/* probe timer expired */
429 					ifinfo->probetimer =
430 						ifinfo->probeinterval;
431 					probe = 1;
432 					ifinfo->state = IFS_PROBE;
433 				}
434 
435 				if (probe && mobile_node)
436 					defrouter_probe(ifinfo->sdl->sdl_index);
437 				break;
438 			}
439 			case IFS_DELAY:
440 				ifinfo->state = IFS_PROBE;
441 				sendpacket(ifinfo);
442 				break;
443 			case IFS_PROBE:
444 				if (ifinfo->probes < MAX_RTR_SOLICITATIONS)
445 					sendpacket(ifinfo);
446 				else {
447 					warnmsg(LOG_INFO, __FUNCTION__,
448 						"No answer "
449 						"after sending %d RSs",
450 						ifinfo->probes);
451 					ifinfo->probes = 0;
452 					ifinfo->state = IFS_IDLE;
453 				}
454 				break;
455 			}
456 			rtsol_timer_update(ifinfo);
457 		}
458 
459 		if (TIMEVAL_LT(ifinfo->expire, rtsol_timer))
460 			rtsol_timer = ifinfo->expire;
461 	}
462 
463 	if (TIMEVAL_EQ(rtsol_timer, tm_max)) {
464 		warnmsg(LOG_DEBUG, __FUNCTION__, "there is no timer");
465 		return(NULL);
466 	}
467 	else if (TIMEVAL_LT(rtsol_timer, now))
468 		/* this may occur when the interval is too small */
469 		returnval.tv_sec = returnval.tv_usec = 0;
470 	else
471 		TIMEVAL_SUB(&rtsol_timer, &now, &returnval);
472 
473 	if (dflag > 1)
474 		warnmsg(LOG_DEBUG, __FUNCTION__, "New timer is %d:%08d",
475 		       returnval.tv_sec, returnval.tv_usec);
476 
477 	return(&returnval);
478 }
479 
480 void
481 rtsol_timer_update(struct ifinfo *ifinfo)
482 {
483 #define	MILLION 1000000
484 #define	DADRETRY 10		/* XXX: adhoc */
485 	long interval;
486 	struct timeval now;
487 
488 	bzero(&ifinfo->timer, sizeof(ifinfo->timer));
489 
490 	switch (ifinfo->state) {
491 	case IFS_DOWN:
492 	case IFS_TENTATIVE:
493 		if (++ifinfo->dadcount > DADRETRY) {
494 			ifinfo->dadcount = 0;
495 			ifinfo->timer.tv_sec = PROBE_INTERVAL;
496 		}
497 		else
498 			ifinfo->timer.tv_sec = 1;
499 		break;
500 	case IFS_IDLE:
501 		if (mobile_node) {
502 			/* XXX should be configurable */
503 			ifinfo->timer.tv_sec = 3;
504 		}
505 		else
506 			ifinfo->timer = tm_max;	/* stop timer(valid?) */
507 		break;
508 	case IFS_DELAY:
509 		interval = random() % (MAX_RTR_SOLICITATION_DELAY * MILLION);
510 		ifinfo->timer.tv_sec = interval / MILLION;
511 		ifinfo->timer.tv_usec = interval % MILLION;
512 		break;
513 	case IFS_PROBE:
514 		ifinfo->timer.tv_sec = RTR_SOLICITATION_INTERVAL;
515 		break;
516 	default:
517 		warnmsg(LOG_ERR, __FUNCTION__,
518 			"illegal interface state(%d) on %s",
519 			ifinfo->state, ifinfo->ifname);
520 		return;
521 	}
522 
523 	/* reset the timer */
524 	if (TIMEVAL_EQ(ifinfo->timer, tm_max)) {
525 		ifinfo->expire = tm_max;
526 		warnmsg(LOG_DEBUG, __FUNCTION__,
527 			"stop timer for %s", ifinfo->ifname);
528 	}
529 	else {
530 		gettimeofday(&now, NULL);
531 		TIMEVAL_ADD(&now, &ifinfo->timer, &ifinfo->expire);
532 
533 		if (dflag > 1)
534 			warnmsg(LOG_DEBUG, __FUNCTION__,
535 				"set timer for %s to %d:%d", ifinfo->ifname,
536 			       (int)ifinfo->timer.tv_sec,
537 			       (int)ifinfo->timer.tv_usec);
538 	}
539 
540 #undef MILLION
541 }
542 
543 /* timer related utility functions */
544 #define	MILLION 1000000
545 
546 /* result = a + b */
547 static void
548 TIMEVAL_ADD(struct timeval *a, struct timeval *b, struct timeval *result)
549 {
550 	long l;
551 
552 	if ((l = a->tv_usec + b->tv_usec) < MILLION) {
553 		result->tv_usec = l;
554 		result->tv_sec = a->tv_sec + b->tv_sec;
555 	}
556 	else {
557 		result->tv_usec = l - MILLION;
558 		result->tv_sec = a->tv_sec + b->tv_sec + 1;
559 	}
560 }
561 
562 /*
563  * result = a - b
564  * XXX: this function assumes that a >= b.
565  */
566 void
567 TIMEVAL_SUB(struct timeval *a, struct timeval *b, struct timeval *result)
568 {
569 	long l;
570 
571 	if ((l = a->tv_usec - b->tv_usec) >= 0) {
572 		result->tv_usec = l;
573 		result->tv_sec = a->tv_sec - b->tv_sec;
574 	}
575 	else {
576 		result->tv_usec = MILLION + l;
577 		result->tv_sec = a->tv_sec - b->tv_sec - 1;
578 	}
579 }
580 
581 static void
582 rtsold_set_dump_file()
583 {
584 	do_dump = 1;
585 }
586 
587 static void
588 usage(char *progname)
589 {
590 	if (progname && progname[strlen(progname) - 1] != 'd')
591 		fprintf(stderr, "usage: rtsol [-dD] interfaces\n");
592 	else
593 		fprintf(stderr, "usage: rtsold [-dDfm1] interfaces\n");
594 	exit(1);
595 }
596 
597 void
598 #if __STDC__
599 warnmsg(int priority, const char *func, const char *msg, ...)
600 #else
601 warnmsg(priority, func, msg, va_alist)
602 	int priority;
603 	const char *func;
604 	const char *msg;
605 	va_dcl
606 #endif
607 {
608 	va_list ap;
609 	char buf[BUFSIZ];
610 
611 	va_start(ap, msg);
612 	if (fflag) {
613 		if (priority <= log_upto) {
614 			(void)vfprintf(stderr, msg, ap);
615 			(void)fprintf(stderr, "\n");
616 		}
617 	} else {
618 		snprintf(buf, sizeof(buf), "<%s> %s", func, msg);
619 		vsyslog(priority, buf, ap);
620 	}
621 	va_end(ap);
622 }
623