rtsold.c revision 62632 
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: head/usr.sbin/rtsold/rtsold.c 62632 2000-07-05 10:14:11Z kris $
30 */
31
32#include <sys/types.h>
33#include <sys/time.h>
34#include <sys/socket.h>
35
36#include <net/if.h>
37#include <net/if_dl.h>
38
39#include <netinet/in.h>
40#include <netinet/icmp6.h>
41
42#include <signal.h>
43#include <unistd.h>
44#include <syslog.h>
45#include <string.h>
46#include <stdlib.h>
47#include <stdio.h>
48#include <errno.h>
49#include <err.h>
50#include <stdarg.h>
51#include "rtsold.h"
52
53struct ifinfo *iflist;
54struct timeval tm_max =	{0x7fffffff, 0x7fffffff};
55int dflag;
56static int log_upto = 999;
57static int fflag = 0;
58
59/* protocol constatns */
60#define MAX_RTR_SOLICITATION_DELAY	1 /* second */
61#define RTR_SOLICITATION_INTERVAL	4 /* seconds */
62#define MAX_RTR_SOLICITATIONS		3 /* times */
63
64/* implementation dependent constants */
65#define PROBE_INTERVAL 60	/* secondes XXX: should be configurable */
66
67/* utility macros */
68/* a < b */
69#define TIMEVAL_LT(a, b) (((a).tv_sec < (b).tv_sec) ||\
70			  (((a).tv_sec == (b).tv_sec) && \
71			    ((a).tv_usec < (b).tv_usec)))
72
73/* a <= b */
74#define TIMEVAL_LEQ(a, b) (((a).tv_sec < (b).tv_sec) ||\
75			   (((a).tv_sec == (b).tv_sec) &&\
76 			    ((a).tv_usec <= (b).tv_usec)))
77
78/* a == b */
79#define TIMEVAL_EQ(a, b) (((a).tv_sec==(b).tv_sec) && ((a).tv_usec==(b).tv_usec))
80
81int main __P((int argc, char *argv[]));
82
83/* static variables and functions */
84static int mobile_node = 0;
85static int do_dump;
86static char *dumpfilename = "/var/run/rtsold.dump"; /* XXX: should be configurable */
87static char *pidfilename = "/var/run/rtsold.pid"; /* should be configurable */
88
89static int ifconfig __P((char *ifname));
90#if 0
91static int ifreconfig __P((char *ifname));
92#endif
93static int make_packet __P((struct ifinfo *ifinfo));
94static struct timeval *rtsol_check_timer __P((void));
95static void TIMEVAL_ADD __P((struct timeval *a, struct timeval *b,
96			     struct timeval *result));
97static void TIMEVAL_SUB __P((struct timeval *a, struct timeval *b,
98			     struct timeval *result));
99
100static void rtsold_set_dump_file __P((void));
101static void usage __P((char *progname));
102
103int
104main(argc, argv)
105	int argc;
106	char *argv[];
107{
108	int s, ch;
109	int once = 0;
110	struct timeval *timeout;
111	struct fd_set fdset;
112	char *argv0;
113	char *opts;
114
115	/*
116	 * Initialization
117	 */
118	argv0 = argv[0];
119
120	/* get option */
121	if (argv0 && argv0[strlen(argv0) - 1] != 'd') {
122		fflag = 1;
123		once = 1;
124		opts = "dD";
125	} else
126		opts = "dDfm1";
127
128	while ((ch = getopt(argc, argv, opts)) != -1) {
129		switch(ch) {
130		 case 'd':
131			 dflag = 1;
132			 break;
133		 case 'D':
134			 dflag = 2;
135			 break;
136		 case 'f':
137			 fflag = 1;
138			 break;
139		 case 'm':
140			 mobile_node = 1;
141			 break;
142		 case '1':
143			 once = 1;
144			 break;
145		 default:
146			 usage(argv0);
147		}
148	}
149	argc -= optind;
150	argv += optind;
151	if (argc == 0)
152		usage(argv0);
153
154	/* set log level */
155	if (dflag == 0)
156		log_upto = LOG_NOTICE;
157	if (!fflag) {
158		char *ident;
159		ident = strrchr(argv0, '/');
160		if (!ident)
161			ident = argv0;
162		else
163			ident++;
164		openlog(ident, LOG_NDELAY|LOG_PID, LOG_DAEMON);
165		if (log_upto >= 0)
166			setlogmask(LOG_UPTO(log_upto));
167	}
168
169#ifndef HAVE_ARC4RANDOM
170	/* random value initilization */
171	srandom((u_long)time(NULL));
172#endif
173
174	/* warn if accept_rtadv is down */
175	if (!getinet6sysctl(IPV6CTL_ACCEPT_RTADV))
176		warnx("kernel is configured not to accept RAs");
177
178	/* initialization to dump internal status to a file */
179	if (signal(SIGUSR1, (void *)rtsold_set_dump_file) < 0)
180		errx(1, "failed to set signal for dump status");
181
182	/*
183	 * Open a socket for sending RS and receiving RA.
184	 * This should be done before calling ifinit(), since the function
185	 * uses the socket.
186	 */
187	if ((s = sockopen()) < 0)
188		errx(1, "failed to open a socket");
189
190	/* configuration per interface */
191	if (ifinit())
192		errx(1, "failed to initilizatoin interfaces");
193	while (argc--) {
194		if (ifconfig(*argv))
195			errx(1, "failed to initialize %s", *argv);
196		argv++;
197	}
198
199	/* setup for probing default routers */
200	if (probe_init())
201		errx(1, "failed to setup for probing routers");
202
203	if (!fflag)
204		daemon(0, 0);		/* act as a daemon */
205
206	/* dump the current pid */
207	if (!once) {
208		pid_t pid = getpid();
209		FILE *fp;
210
211		if ((fp = fopen(pidfilename, "w")) == NULL)
212			warnmsg(LOG_ERR, __FUNCTION__,
213				"failed to open a log file(%s)",
214				pidfilename, strerror(errno));
215		else {
216			fprintf(fp, "%d\n", pid);
217			fclose(fp);
218		}
219	}
220
221	FD_ZERO(&fdset);
222	FD_SET(s, &fdset);
223	while (1) {		/* main loop */
224		int e;
225		struct fd_set select_fd = fdset;
226
227		if (do_dump) {	/* SIGUSR1 */
228			do_dump = 0;
229			rtsold_dump_file(dumpfilename);
230		}
231
232		timeout = rtsol_check_timer();
233
234		if (once) {
235			struct ifinfo *ifi;
236
237			/* if we have no timeout, we are done (or failed) */
238			if (timeout == NULL)
239				break;
240
241			/* if all interfaces have got RA packet, we are done */
242			for (ifi = iflist; ifi; ifi = ifi->next) {
243				if (ifi->state != IFS_DOWN && ifi->racnt == 0)
244					break;
245			}
246			if (ifi == NULL)
247				break;
248		}
249
250		if ((e = select(s + 1, &select_fd, NULL, NULL, timeout)) < 1) {
251			if (e < 0 && errno != EINTR) {
252				warnmsg(LOG_ERR, __FUNCTION__, "select: %s",
253				       strerror(errno));
254			}
255			continue;
256		}
257
258		/* packet reception */
259		if (FD_ISSET(s, &fdset))
260			rtsol_input(s);
261	}
262	/* NOTREACHED */
263
264	return 0;
265}
266
267static int
268ifconfig(char *ifname)
269{
270	struct ifinfo *ifinfo;
271	struct sockaddr_dl *sdl;
272	int flags;
273
274	if ((sdl = if_nametosdl(ifname)) == NULL) {
275		warnmsg(LOG_ERR, __FUNCTION__,
276		       "failed to get link layer information for %s", ifname);
277		return(-1);
278	}
279	if (find_ifinfo(sdl->sdl_index)) {
280		warnmsg(LOG_ERR, __FUNCTION__,
281			"interface %s was already cofigured", ifname);
282		free(sdl);
283		return(-1);
284	}
285
286	if ((ifinfo = malloc(sizeof(*ifinfo))) == NULL) {
287		warnmsg(LOG_ERR, __FUNCTION__, "memory allocation failed");
288		free(sdl);
289		return(-1);
290	}
291	memset(ifinfo, 0, sizeof(*ifinfo));
292	ifinfo->sdl = sdl;
293
294	strncpy(ifinfo->ifname, ifname, sizeof(ifinfo->ifname));
295
296	/* construct a router solicitation message */
297	if (make_packet(ifinfo))
298		goto bad;
299
300	/*
301	 * check if the interface is available.
302	 * also check if SIOCGIFMEDIA ioctl is OK on the interface.
303	 */
304	ifinfo->mediareqok = 1;
305	ifinfo->active = interface_status(ifinfo);
306	if (!ifinfo->mediareqok) {
307		/*
308		 * probe routers periodically even if the link status
309		 * does not change.
310		 */
311		ifinfo->probeinterval = PROBE_INTERVAL;
312	}
313
314	/* activate interface: interface_up returns 0 on success */
315	flags = interface_up(ifinfo->ifname);
316	if (flags == 0)
317		ifinfo->state = IFS_DELAY;
318	else if (flags == IFS_TENTATIVE)
319		ifinfo->state = IFS_TENTATIVE;
320	else
321		ifinfo->state = IFS_DOWN;
322
323	rtsol_timer_update(ifinfo);
324
325	/* link into chain */
326	if (iflist)
327		ifinfo->next = iflist;
328	iflist = ifinfo;
329
330	return(0);
331
332  bad:
333	free(ifinfo->sdl);
334	free(ifinfo);
335	return(-1);
336}
337
338#if 0
339static int
340ifreconfig(char *ifname)
341{
342	struct ifinfo *ifi, *prev;
343	int rv;
344
345	prev = NULL;
346	for (ifi = iflist; ifi; ifi = ifi->next) {
347		if (strncmp(ifi->ifname, ifname, sizeof(ifi->ifname)) == 0)
348			break;
349		prev = ifi;
350	}
351	prev->next = ifi->next;
352
353	rv = ifconfig(ifname);
354
355	/* reclaim it after ifconfig() in case ifname is pointer inside ifi */
356	if (ifi->rs_data)
357		free(ifi->rs_data);
358	free(ifi->sdl);
359	free(ifi);
360
361	return rv;
362}
363#endif
364
365struct ifinfo *
366find_ifinfo(int ifindex)
367{
368	struct ifinfo *ifi;
369
370	for (ifi = iflist; ifi; ifi = ifi->next)
371		if (ifi->sdl->sdl_index == ifindex)
372			return(ifi);
373
374	return(NULL);
375}
376
377static int
378make_packet(struct ifinfo *ifinfo)
379{
380	char *buf;
381	struct nd_router_solicit *rs;
382	size_t packlen = sizeof(struct nd_router_solicit), lladdroptlen = 0;
383
384	if ((lladdroptlen = lladdropt_length(ifinfo->sdl)) == 0) {
385		warnmsg(LOG_INFO, __FUNCTION__,
386			"link-layer address option has null length"
387		       " on %s. Treat as not included.", ifinfo->ifname);
388	}
389	packlen += lladdroptlen;
390	ifinfo->rs_datalen = packlen;
391
392	/* allocate buffer */
393	if ((buf = malloc(packlen)) == NULL) {
394		warnmsg(LOG_ERR, __FUNCTION__,
395			"memory allocation failed for %s", ifinfo->ifname);
396		return(-1);
397	}
398	ifinfo->rs_data = buf;
399
400	/* fill in the message */
401	rs = (struct nd_router_solicit *)buf;
402	rs->nd_rs_type = ND_ROUTER_SOLICIT;
403	rs->nd_rs_code = 0;
404	rs->nd_rs_cksum = 0;
405	rs->nd_rs_reserved = 0;
406	buf += sizeof(*rs);
407
408	/* fill in source link-layer address option */
409	if (lladdroptlen)
410		lladdropt_fill(ifinfo->sdl, (struct nd_opt_hdr *)buf);
411
412	return(0);
413}
414
415static struct timeval *
416rtsol_check_timer()
417{
418	static struct timeval returnval;
419	struct timeval now, rtsol_timer;
420	struct ifinfo *ifinfo;
421	int flags;
422
423	gettimeofday(&now, NULL);
424
425	rtsol_timer = tm_max;
426
427	for (ifinfo = iflist; ifinfo; ifinfo = ifinfo->next) {
428		if (TIMEVAL_LEQ(ifinfo->expire, now)) {
429			if (dflag > 1)
430				warnmsg(LOG_DEBUG, __FUNCTION__,
431					"timer expiration on %s, "
432				       "state = %d", ifinfo->ifname,
433				       ifinfo->state);
434
435			switch(ifinfo->state) {
436			case IFS_DOWN:
437			case IFS_TENTATIVE:
438				/* interface_up returns 0 on success */
439				flags = interface_up(ifinfo->ifname);
440				if (flags == 0)
441					ifinfo->state = IFS_DELAY;
442				else if (flags == IFS_TENTATIVE)
443					ifinfo->state = IFS_TENTATIVE;
444				else
445					ifinfo->state = IFS_DOWN;
446				break;
447			case IFS_IDLE:
448			{
449				int oldstatus = ifinfo->active;
450				int probe = 0;
451
452				ifinfo->active =
453					interface_status(ifinfo);
454
455				if (oldstatus != ifinfo->active) {
456					warnmsg(LOG_DEBUG, __FUNCTION__,
457						"%s status is changed"
458						" from %d to %d",
459						ifinfo->ifname,
460						oldstatus, ifinfo->active);
461					probe = 1;
462					ifinfo->state = IFS_DELAY;
463				}
464				else if (ifinfo->probeinterval &&
465					 (ifinfo->probetimer -=
466					  ifinfo->timer.tv_sec) <= 0) {
467					/* probe timer expired */
468					ifinfo->probetimer =
469						ifinfo->probeinterval;
470					probe = 1;
471					ifinfo->state = IFS_PROBE;
472				}
473
474				if (probe && mobile_node)
475					defrouter_probe(ifinfo->sdl->sdl_index);
476				break;
477			}
478			case IFS_DELAY:
479				ifinfo->state = IFS_PROBE;
480				sendpacket(ifinfo);
481				break;
482			case IFS_PROBE:
483				if (ifinfo->probes < MAX_RTR_SOLICITATIONS)
484					sendpacket(ifinfo);
485				else {
486					warnmsg(LOG_INFO, __FUNCTION__,
487						"No answer "
488						"after sending %d RSs",
489						ifinfo->probes);
490					ifinfo->probes = 0;
491					ifinfo->state = IFS_IDLE;
492				}
493				break;
494			}
495			rtsol_timer_update(ifinfo);
496		}
497
498		if (TIMEVAL_LT(ifinfo->expire, rtsol_timer))
499			rtsol_timer = ifinfo->expire;
500	}
501
502	if (TIMEVAL_EQ(rtsol_timer, tm_max)) {
503		warnmsg(LOG_DEBUG, __FUNCTION__, "there is no timer");
504		return(NULL);
505	}
506	else if (TIMEVAL_LT(rtsol_timer, now))
507		/* this may occur when the interval is too small */
508		returnval.tv_sec = returnval.tv_usec = 0;
509	else
510		TIMEVAL_SUB(&rtsol_timer, &now, &returnval);
511
512	if (dflag > 1)
513		warnmsg(LOG_DEBUG, __FUNCTION__, "New timer is %d:%08d",
514		       returnval.tv_sec, returnval.tv_usec);
515
516	return(&returnval);
517}
518
519void
520rtsol_timer_update(struct ifinfo *ifinfo)
521{
522#define MILLION 1000000
523#define DADRETRY 10		/* XXX: adhoc */
524	long interval;
525	struct timeval now;
526
527	bzero(&ifinfo->timer, sizeof(ifinfo->timer));
528
529	switch (ifinfo->state) {
530	case IFS_DOWN:
531	case IFS_TENTATIVE:
532		if (++ifinfo->dadcount > DADRETRY) {
533			ifinfo->dadcount = 0;
534			ifinfo->timer.tv_sec = PROBE_INTERVAL;
535		}
536		else
537			ifinfo->timer.tv_sec = 1;
538		break;
539	case IFS_IDLE:
540		if (mobile_node) {
541			/* XXX should be configurable */
542			ifinfo->timer.tv_sec = 3;
543		}
544		else
545			ifinfo->timer = tm_max;	/* stop timer(valid?) */
546		break;
547	case IFS_DELAY:
548#ifndef HAVE_ARC4RANDOM
549		interval = random() % (MAX_RTR_SOLICITATION_DELAY * MILLION);
550#else
551		interval = arc4random() % (MAX_RTR_SOLICITATION_DELAY * MILLION);
552#endif
553		ifinfo->timer.tv_sec = interval / MILLION;
554		ifinfo->timer.tv_usec = interval % MILLION;
555		break;
556	case IFS_PROBE:
557		ifinfo->timer.tv_sec = RTR_SOLICITATION_INTERVAL;
558		break;
559	default:
560		warnmsg(LOG_ERR, __FUNCTION__,
561			"illegal interface state(%d) on %s",
562			ifinfo->state, ifinfo->ifname);
563		return;
564	}
565
566	/* reset the timer */
567	if (TIMEVAL_EQ(ifinfo->timer, tm_max)) {
568		ifinfo->expire = tm_max;
569		warnmsg(LOG_DEBUG, __FUNCTION__,
570			"stop timer for %s", ifinfo->ifname);
571	}
572	else {
573		gettimeofday(&now, NULL);
574		TIMEVAL_ADD(&now, &ifinfo->timer, &ifinfo->expire);
575
576		if (dflag > 1)
577			warnmsg(LOG_DEBUG, __FUNCTION__,
578				"set timer for %s to %d:%d", ifinfo->ifname,
579			       (int)ifinfo->timer.tv_sec,
580			       (int)ifinfo->timer.tv_usec);
581	}
582
583#undef MILLION
584}
585
586/* timer related utility functions */
587#define MILLION 1000000
588
589/* result = a + b */
590static void
591TIMEVAL_ADD(struct timeval *a, struct timeval *b, struct timeval *result)
592{
593	long l;
594
595	if ((l = a->tv_usec + b->tv_usec) < MILLION) {
596		result->tv_usec = l;
597		result->tv_sec = a->tv_sec + b->tv_sec;
598	}
599	else {
600		result->tv_usec = l - MILLION;
601		result->tv_sec = a->tv_sec + b->tv_sec + 1;
602	}
603}
604
605/*
606 * result = a - b
607 * XXX: this function assumes that a >= b.
608 */
609void
610TIMEVAL_SUB(struct timeval *a, struct timeval *b, struct timeval *result)
611{
612	long l;
613
614	if ((l = a->tv_usec - b->tv_usec) >= 0) {
615		result->tv_usec = l;
616		result->tv_sec = a->tv_sec - b->tv_sec;
617	}
618	else {
619		result->tv_usec = MILLION + l;
620		result->tv_sec = a->tv_sec - b->tv_sec - 1;
621	}
622}
623
624static void
625rtsold_set_dump_file()
626{
627	do_dump = 1;
628}
629
630static void
631usage(char *progname)
632{
633	if (progname && progname[strlen(progname) - 1] != 'd')
634		fprintf(stderr, "usage: rtsol [-dD] interfaces\n");
635	else
636		fprintf(stderr, "usage: rtsold [-dDfm1] interfaces\n");
637	exit(1);
638}
639
640void
641#if __STDC__
642warnmsg(int priority, const char *func, const char *msg, ...)
643#else
644warnmsg(priority, func, msg, va_alist)
645	int priority;
646	const char *func;
647	const char *msg;
648	va_dcl
649#endif
650{
651	va_list ap;
652	char buf[BUFSIZ];
653
654	va_start(ap, msg);
655	if (fflag) {
656		if (priority <= log_upto) {
657			(void)vfprintf(stderr, msg, ap);
658			(void)fprintf(stderr, "\n");
659		}
660	} else {
661		snprintf(buf, sizeof(buf), "<%s> %s", func, msg);
662		vsyslog(priority, buf, ap);
663	}
664	va_end(ap);
665}
666