rtsold.c revision 124525 
1/*	$KAME: rtsold.c,v 1.67 2003/05/17 18:16:15 itojun Exp $	*/
2
3/*
4 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
5 * 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 project 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 PROJECT 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 PROJECT 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: head/usr.sbin/rtsold/rtsold.c 124525 2004-01-14 17:42:03Z ume $
32 */
33
34#include <sys/types.h>
35#include <sys/time.h>
36#include <sys/socket.h>
37#include <sys/param.h>
38
39#include <net/if.h>
40#include <net/if_dl.h>
41
42#include <netinet/in.h>
43#include <netinet/icmp6.h>
44
45#include <signal.h>
46#include <unistd.h>
47#include <syslog.h>
48#include <string.h>
49#include <stdlib.h>
50#include <stdio.h>
51#include <errno.h>
52#include <err.h>
53#include <stdarg.h>
54#include <ifaddrs.h>
55#ifdef HAVE_POLL_H
56#include <poll.h>
57#endif
58
59#include "rtsold.h"
60
61struct ifinfo *iflist;
62struct timeval tm_max =	{0x7fffffff, 0x7fffffff};
63static int log_upto = 999;
64static int fflag = 0;
65static int Fflag = 0;	/* force setting sysctl parameters */
66
67int aflag = 0;
68int dflag = 0;
69
70char *otherconf_script;
71
72/* protocol constatns */
73#define MAX_RTR_SOLICITATION_DELAY	1 /* second */
74#define RTR_SOLICITATION_INTERVAL	4 /* seconds */
75#define MAX_RTR_SOLICITATIONS		3 /* times */
76
77/*
78 * implementation dependent constants in seconds
79 * XXX: should be configurable
80 */
81#define PROBE_INTERVAL 60
82
83int main __P((int, char **));
84
85/* static variables and functions */
86static int mobile_node = 0;
87static int do_dump;
88static char *dumpfilename = "/var/run/rtsold.dump"; /* XXX: should be configurable */
89static char *pidfilename = "/var/run/rtsold.pid"; /* should be configurable */
90
91#if 0
92static int ifreconfig __P((char *));
93#endif
94static int make_packet __P((struct ifinfo *));
95static struct timeval *rtsol_check_timer __P((void));
96
97static void rtsold_set_dump_file __P((int));
98static void usage __P((char *));
99
100int
101main(int argc, char **argv)
102{
103	int s, ch, once = 0;
104	struct timeval *timeout;
105	char *argv0, *opts;
106#ifdef HAVE_POLL_H
107	struct pollfd set[2];
108#else
109	fd_set *fdsetp, *selectfdp;
110	int fdmasks;
111	int maxfd;
112#endif
113	int rtsock;
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 = "adDFO:";
125	} else
126		opts = "adDfFm1O:";
127
128	while ((ch = getopt(argc, argv, opts)) != -1) {
129		switch (ch) {
130		case 'a':
131			aflag = 1;
132			break;
133		case 'd':
134			dflag = 1;
135			break;
136		case 'D':
137			dflag = 2;
138			break;
139		case 'f':
140			fflag = 1;
141			break;
142		case 'F':
143			Fflag = 1;
144			break;
145		case 'm':
146			mobile_node = 1;
147			break;
148		case '1':
149			once = 1;
150			break;
151		case 'O':
152			otherconf_script = optarg;
153			break;
154		default:
155			usage(argv0);
156			/*NOTREACHED*/
157		}
158	}
159	argc -= optind;
160	argv += optind;
161
162	if ((!aflag && argc == 0) || (aflag && argc != 0)) {
163		usage(argv0);
164		/*NOTREACHED*/
165	}
166
167	/* set log level */
168	if (dflag == 0)
169		log_upto = LOG_NOTICE;
170	if (!fflag) {
171		char *ident;
172
173		ident = strrchr(argv0, '/');
174		if (!ident)
175			ident = argv0;
176		else
177			ident++;
178		openlog(ident, LOG_NDELAY|LOG_PID, LOG_DAEMON);
179		if (log_upto >= 0)
180			setlogmask(LOG_UPTO(log_upto));
181	}
182
183	if (otherconf_script && *otherconf_script != '/') {
184		errx(1, "configuration script (%s) must be an absolute path",
185		    otherconf_script);
186	}
187
188#ifndef HAVE_ARC4RANDOM
189	/* random value initialization */
190	srandom((u_long)time(NULL));
191#endif
192
193	if (Fflag) {
194		setinet6sysctl(IPV6CTL_ACCEPT_RTADV, 1);
195		setinet6sysctl(IPV6CTL_FORWARDING, 0);
196	} else {
197		/* warn if accept_rtadv is down */
198		if (!getinet6sysctl(IPV6CTL_ACCEPT_RTADV))
199			warnx("kernel is configured not to accept RAs");
200		/* warn if forwarding is up */
201		if (getinet6sysctl(IPV6CTL_FORWARDING))
202			warnx("kernel is configured as a router, not a host");
203	}
204
205	/* initialization to dump internal status to a file */
206	signal(SIGUSR1, rtsold_set_dump_file);
207
208	if (!fflag)
209		daemon(0, 0);		/* act as a daemon */
210
211	/*
212	 * Open a socket for sending RS and receiving RA.
213	 * This should be done before calling ifinit(), since the function
214	 * uses the socket.
215	 */
216	if ((s = sockopen()) < 0) {
217		warnmsg(LOG_ERR, __func__, "failed to open a socket");
218		exit(1);
219		/*NOTREACHED*/
220	}
221#ifdef HAVE_POLL_H
222	set[0].fd = s;
223	set[0].events = POLLIN;
224#else
225	maxfd = s;
226#endif
227
228#ifdef HAVE_POLL_H
229	set[1].fd = -1;
230#endif
231
232	if ((rtsock = rtsock_open()) < 0) {
233		warnmsg(LOG_ERR, __func__, "failed to open a socket");
234		exit(1);
235		/*NOTREACHED*/
236	}
237#ifdef HAVE_POLL_H
238	set[1].fd = rtsock;
239	set[1].events = POLLIN;
240#else
241	if (rtsock > maxfd)
242		maxfd = rtsock;
243#endif
244
245#ifndef HAVE_POLL_H
246	fdmasks = howmany(maxfd + 1, NFDBITS) * sizeof(fd_mask);
247	if ((fdsetp = malloc(fdmasks)) == NULL) {
248		err(1, "malloc");
249		/*NOTREACHED*/
250	}
251	if ((selectfdp = malloc(fdmasks)) == NULL) {
252		err(1, "malloc");
253		/*NOTREACHED*/
254	}
255#endif
256
257	/* configuration per interface */
258	if (ifinit()) {
259		warnmsg(LOG_ERR, __func__,
260		    "failed to initilizatoin interfaces");
261		exit(1);
262		/*NOTREACHED*/
263	}
264	if (aflag)
265		argv = autoifprobe();
266	while (argv && *argv) {
267		if (ifconfig(*argv)) {
268			warnmsg(LOG_ERR, __func__,
269			    "failed to initialize %s", *argv);
270			exit(1);
271			/*NOTREACHED*/
272		}
273		argv++;
274	}
275
276	/* setup for probing default routers */
277	if (probe_init()) {
278		warnmsg(LOG_ERR, __func__,
279		    "failed to setup for probing routers");
280		exit(1);
281		/*NOTREACHED*/
282	}
283
284	/* dump the current pid */
285	if (!once) {
286		pid_t pid = getpid();
287		FILE *fp;
288
289		if ((fp = fopen(pidfilename, "w")) == NULL)
290			warnmsg(LOG_ERR, __func__,
291			    "failed to open a pid log file(%s): %s",
292			    pidfilename, strerror(errno));
293		else {
294			fprintf(fp, "%d\n", pid);
295			fclose(fp);
296		}
297	}
298
299#ifndef HAVE_POLL_H
300	memset(fdsetp, 0, fdmasks);
301	FD_SET(s, fdsetp);
302	FD_SET(rtsock, fdsetp);
303#endif
304	while (1) {		/* main loop */
305		int e;
306
307#ifndef HAVE_POLL_H
308		memcpy(selectfdp, fdsetp, fdmasks);
309#endif
310
311		if (do_dump) {	/* SIGUSR1 */
312			do_dump = 0;
313			rtsold_dump_file(dumpfilename);
314		}
315
316		timeout = rtsol_check_timer();
317
318		if (once) {
319			struct ifinfo *ifi;
320
321			/* if we have no timeout, we are done (or failed) */
322			if (timeout == NULL)
323				break;
324
325			/* if all interfaces have got RA packet, we are done */
326			for (ifi = iflist; ifi; ifi = ifi->next) {
327				if (ifi->state != IFS_DOWN && ifi->racnt == 0)
328					break;
329			}
330			if (ifi == NULL)
331				break;
332		}
333#ifdef HAVE_POLL_H
334		e = poll(set, 2, timeout ? (timeout->tv_sec * 1000 + timeout->tv_usec / 1000) : INFTIM);
335#else
336		e = select(maxfd + 1, selectfdp, NULL, NULL, timeout);
337#endif
338		if (e < 1) {
339			if (e < 0 && errno != EINTR) {
340				warnmsg(LOG_ERR, __func__, "select: %s",
341				    strerror(errno));
342			}
343			continue;
344		}
345
346		/* packet reception */
347#ifdef HAVE_POLL_H
348		if (set[1].revents & POLLIN)
349#else
350		if (FD_ISSET(rtsock, selectfdp))
351#endif
352			rtsock_input(rtsock);
353#ifdef HAVE_POLL_H
354		if (set[0].revents & POLLIN)
355#else
356		if (FD_ISSET(s, selectfdp))
357#endif
358			rtsol_input(s);
359	}
360	/* NOTREACHED */
361
362	return 0;
363}
364
365int
366ifconfig(char *ifname)
367{
368	struct ifinfo *ifinfo;
369	struct sockaddr_dl *sdl;
370	int flags;
371
372	if ((sdl = if_nametosdl(ifname)) == NULL) {
373		warnmsg(LOG_ERR, __func__,
374		    "failed to get link layer information for %s", ifname);
375		return(-1);
376	}
377	if (find_ifinfo(sdl->sdl_index)) {
378		warnmsg(LOG_ERR, __func__,
379		    "interface %s was already configured", ifname);
380		free(sdl);
381		return(-1);
382	}
383
384	if ((ifinfo = malloc(sizeof(*ifinfo))) == NULL) {
385		warnmsg(LOG_ERR, __func__, "memory allocation failed");
386		free(sdl);
387		return(-1);
388	}
389	memset(ifinfo, 0, sizeof(*ifinfo));
390	ifinfo->sdl = sdl;
391
392	strlcpy(ifinfo->ifname, ifname, sizeof(ifinfo->ifname));
393
394	/* construct a router solicitation message */
395	if (make_packet(ifinfo))
396		goto bad;
397
398	/* set link ID of this interface. */
399#ifdef HAVE_SCOPELIB
400	if (inet_zoneid(AF_INET6, 2, ifname, &ifinfo->linkid))
401		goto bad;
402#else
403	/* XXX: assume interface IDs as link IDs */
404	ifinfo->linkid = ifinfo->sdl->sdl_index;
405#endif
406
407	/*
408	 * check if the interface is available.
409	 * also check if SIOCGIFMEDIA ioctl is OK on the interface.
410	 */
411	ifinfo->mediareqok = 1;
412	ifinfo->active = interface_status(ifinfo);
413	if (!ifinfo->mediareqok) {
414		/*
415		 * probe routers periodically even if the link status
416		 * does not change.
417		 */
418		ifinfo->probeinterval = PROBE_INTERVAL;
419	}
420
421	/* activate interface: interface_up returns 0 on success */
422	flags = interface_up(ifinfo->ifname);
423	if (flags == 0)
424		ifinfo->state = IFS_DELAY;
425	else if (flags == IFS_TENTATIVE)
426		ifinfo->state = IFS_TENTATIVE;
427	else
428		ifinfo->state = IFS_DOWN;
429
430	rtsol_timer_update(ifinfo);
431
432	/* link into chain */
433	if (iflist)
434		ifinfo->next = iflist;
435	iflist = ifinfo;
436
437	return(0);
438
439bad:
440	free(ifinfo->sdl);
441	free(ifinfo);
442	return(-1);
443}
444
445void
446iflist_init(void)
447{
448	struct ifinfo *ifi, *next;
449
450	for (ifi = iflist; ifi; ifi = next) {
451		next = ifi->next;
452		if (ifi->sdl)
453			free(ifi->sdl);
454		if (ifi->rs_data)
455			free(ifi->rs_data);
456		free(ifi);
457		iflist = NULL;
458	}
459}
460
461#if 0
462static int
463ifreconfig(char *ifname)
464{
465	struct ifinfo *ifi, *prev;
466	int rv;
467
468	prev = NULL;
469	for (ifi = iflist; ifi; ifi = ifi->next) {
470		if (strncmp(ifi->ifname, ifname, sizeof(ifi->ifname)) == 0)
471			break;
472		prev = ifi;
473	}
474	prev->next = ifi->next;
475
476	rv = ifconfig(ifname);
477
478	/* reclaim it after ifconfig() in case ifname is pointer inside ifi */
479	if (ifi->rs_data)
480		free(ifi->rs_data);
481	free(ifi->sdl);
482	free(ifi);
483	return rv;
484}
485#endif
486
487struct ifinfo *
488find_ifinfo(int ifindex)
489{
490	struct ifinfo *ifi;
491
492	for (ifi = iflist; ifi; ifi = ifi->next)
493		if (ifi->sdl->sdl_index == ifindex)
494			return(ifi);
495	return(NULL);
496}
497
498static int
499make_packet(struct ifinfo *ifinfo)
500{
501	size_t packlen = sizeof(struct nd_router_solicit), lladdroptlen = 0;
502	struct nd_router_solicit *rs;
503	char *buf;
504
505	if ((lladdroptlen = lladdropt_length(ifinfo->sdl)) == 0) {
506		warnmsg(LOG_INFO, __func__,
507		    "link-layer address option has null length"
508		    " on %s. Treat as not included.", ifinfo->ifname);
509	}
510	packlen += lladdroptlen;
511	ifinfo->rs_datalen = packlen;
512
513	/* allocate buffer */
514	if ((buf = malloc(packlen)) == NULL) {
515		warnmsg(LOG_ERR, __func__,
516		    "memory allocation failed for %s", ifinfo->ifname);
517		return(-1);
518	}
519	ifinfo->rs_data = buf;
520
521	/* fill in the message */
522	rs = (struct nd_router_solicit *)buf;
523	rs->nd_rs_type = ND_ROUTER_SOLICIT;
524	rs->nd_rs_code = 0;
525	rs->nd_rs_cksum = 0;
526	rs->nd_rs_reserved = 0;
527	buf += sizeof(*rs);
528
529	/* fill in source link-layer address option */
530	if (lladdroptlen)
531		lladdropt_fill(ifinfo->sdl, (struct nd_opt_hdr *)buf);
532
533	return(0);
534}
535
536static struct timeval *
537rtsol_check_timer(void)
538{
539	static struct timeval returnval;
540	struct timeval now, rtsol_timer;
541	struct ifinfo *ifinfo;
542	int flags;
543
544	gettimeofday(&now, NULL);
545
546	rtsol_timer = tm_max;
547
548	for (ifinfo = iflist; ifinfo; ifinfo = ifinfo->next) {
549		if (timercmp(&ifinfo->expire, &now, <=)) {
550			if (dflag > 1)
551				warnmsg(LOG_DEBUG, __func__,
552				    "timer expiration on %s, "
553				    "state = %d", ifinfo->ifname,
554				    ifinfo->state);
555
556			switch (ifinfo->state) {
557			case IFS_DOWN:
558			case IFS_TENTATIVE:
559				/* interface_up returns 0 on success */
560				flags = interface_up(ifinfo->ifname);
561				if (flags == 0)
562					ifinfo->state = IFS_DELAY;
563				else if (flags == IFS_TENTATIVE)
564					ifinfo->state = IFS_TENTATIVE;
565				else
566					ifinfo->state = IFS_DOWN;
567				break;
568			case IFS_IDLE:
569			{
570				int oldstatus = ifinfo->active;
571				int probe = 0;
572
573				ifinfo->active = interface_status(ifinfo);
574
575				if (oldstatus != ifinfo->active) {
576					warnmsg(LOG_DEBUG, __func__,
577					    "%s status is changed"
578					    " from %d to %d",
579					    ifinfo->ifname,
580					    oldstatus, ifinfo->active);
581					probe = 1;
582					ifinfo->state = IFS_DELAY;
583				} else if (ifinfo->probeinterval &&
584				    (ifinfo->probetimer -=
585				    ifinfo->timer.tv_sec) <= 0) {
586					/* probe timer expired */
587					ifinfo->probetimer =
588					    ifinfo->probeinterval;
589					probe = 1;
590					ifinfo->state = IFS_PROBE;
591				}
592
593				/*
594				 * If we need a probe, clear the previous
595				 * status wrt the "other" configuration.
596				 */
597				if (probe)
598					ifinfo->otherconfig = 0;
599
600				if (probe && mobile_node)
601					defrouter_probe(ifinfo);
602				break;
603			}
604			case IFS_DELAY:
605				ifinfo->state = IFS_PROBE;
606				sendpacket(ifinfo);
607				break;
608			case IFS_PROBE:
609				if (ifinfo->probes < MAX_RTR_SOLICITATIONS)
610					sendpacket(ifinfo);
611				else {
612					warnmsg(LOG_INFO, __func__,
613					    "No answer after sending %d RSs",
614					    ifinfo->probes);
615					ifinfo->probes = 0;
616					ifinfo->state = IFS_IDLE;
617				}
618				break;
619			}
620			rtsol_timer_update(ifinfo);
621		}
622
623		if (timercmp(&ifinfo->expire, &rtsol_timer, <))
624			rtsol_timer = ifinfo->expire;
625	}
626
627	if (timercmp(&rtsol_timer, &tm_max, ==)) {
628		warnmsg(LOG_DEBUG, __func__, "there is no timer");
629		return(NULL);
630	} else if (timercmp(&rtsol_timer, &now, <))
631		/* this may occur when the interval is too small */
632		returnval.tv_sec = returnval.tv_usec = 0;
633	else
634		timersub(&rtsol_timer, &now, &returnval);
635
636	if (dflag > 1)
637		warnmsg(LOG_DEBUG, __func__, "New timer is %ld:%08ld",
638		    (long)returnval.tv_sec, (long)returnval.tv_usec);
639
640	return(&returnval);
641}
642
643void
644rtsol_timer_update(struct ifinfo *ifinfo)
645{
646#define MILLION 1000000
647#define DADRETRY 10		/* XXX: adhoc */
648	long interval;
649	struct timeval now;
650
651	bzero(&ifinfo->timer, sizeof(ifinfo->timer));
652
653	switch (ifinfo->state) {
654	case IFS_DOWN:
655	case IFS_TENTATIVE:
656		if (++ifinfo->dadcount > DADRETRY) {
657			ifinfo->dadcount = 0;
658			ifinfo->timer.tv_sec = PROBE_INTERVAL;
659		} else
660			ifinfo->timer.tv_sec = 1;
661		break;
662	case IFS_IDLE:
663		if (mobile_node) {
664			/* XXX should be configurable */
665			ifinfo->timer.tv_sec = 3;
666		}
667		else
668			ifinfo->timer = tm_max;	/* stop timer(valid?) */
669		break;
670	case IFS_DELAY:
671#ifndef HAVE_ARC4RANDOM
672		interval = random() % (MAX_RTR_SOLICITATION_DELAY * MILLION);
673#else
674		interval = arc4random() % (MAX_RTR_SOLICITATION_DELAY * MILLION);
675#endif
676		ifinfo->timer.tv_sec = interval / MILLION;
677		ifinfo->timer.tv_usec = interval % MILLION;
678		break;
679	case IFS_PROBE:
680		if (ifinfo->probes < MAX_RTR_SOLICITATIONS)
681			ifinfo->timer.tv_sec = RTR_SOLICITATION_INTERVAL;
682		else {
683			/*
684			 * After sending MAX_RTR_SOLICITATIONS solicitations,
685			 * we're just waiting for possible replies; there
686			 * will be no more solicatation.  Thus, we change
687			 * the timer value to MAX_RTR_SOLICITATION_DELAY based
688			 * on RFC 2461, Section 6.3.7.
689			 */
690			ifinfo->timer.tv_sec = MAX_RTR_SOLICITATION_DELAY;
691		}
692		break;
693	default:
694		warnmsg(LOG_ERR, __func__,
695		    "illegal interface state(%d) on %s",
696		    ifinfo->state, ifinfo->ifname);
697		return;
698	}
699
700	/* reset the timer */
701	if (timercmp(&ifinfo->timer, &tm_max, ==)) {
702		ifinfo->expire = tm_max;
703		warnmsg(LOG_DEBUG, __func__,
704		    "stop timer for %s", ifinfo->ifname);
705	} else {
706		gettimeofday(&now, NULL);
707		timeradd(&now, &ifinfo->timer, &ifinfo->expire);
708
709		if (dflag > 1)
710			warnmsg(LOG_DEBUG, __func__,
711			    "set timer for %s to %d:%d", ifinfo->ifname,
712			    (int)ifinfo->timer.tv_sec,
713			    (int)ifinfo->timer.tv_usec);
714	}
715
716#undef MILLION
717}
718
719/* timer related utility functions */
720#define MILLION 1000000
721
722static void
723rtsold_set_dump_file(int sig)
724{
725	do_dump = 1;
726}
727
728static void
729usage(char *progname)
730{
731	if (progname && progname[strlen(progname) - 1] != 'd') {
732		fprintf(stderr, "usage: rtsol [-dDF] interfaces...\n");
733		fprintf(stderr, "usage: rtsol [-dDF] -a\n");
734	} else {
735		fprintf(stderr, "usage: rtsold [-adDfFm1] interfaces...\n");
736		fprintf(stderr, "usage: rtsold [-dDfFm1] -a\n");
737	}
738	exit(1);
739}
740
741void
742#if __STDC__
743warnmsg(int priority, const char *func, const char *msg, ...)
744#else
745warnmsg(priority, func, msg, va_alist)
746	int priority;
747	const char *func;
748	const char *msg;
749	va_dcl
750#endif
751{
752	va_list ap;
753	char buf[BUFSIZ];
754
755	va_start(ap, msg);
756	if (fflag) {
757		if (priority <= log_upto) {
758			(void)vfprintf(stderr, msg, ap);
759			(void)fprintf(stderr, "\n");
760		}
761	} else {
762		snprintf(buf, sizeof(buf), "<%s> %s", func, msg);
763		msg = buf;
764		vsyslog(priority, msg, ap);
765	}
766	va_end(ap);
767}
768
769/*
770 * return a list of interfaces which is suitable to sending an RS.
771 */
772char **
773autoifprobe(void)
774{
775	static char **argv = NULL;
776	static int n = 0;
777	char **a;
778	int i, found;
779	struct ifaddrs *ifap, *ifa, *target;
780
781	/* initialize */
782	while (n--)
783		free(argv[n]);
784	if (argv) {
785		free(argv);
786		argv = NULL;
787	}
788	n = 0;
789
790	if (getifaddrs(&ifap) != 0)
791		return NULL;
792
793	target = NULL;
794	/* find an ethernet */
795	for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
796		if ((ifa->ifa_flags & IFF_UP) == 0)
797			continue;
798		if ((ifa->ifa_flags & IFF_POINTOPOINT) != 0)
799			continue;
800		if ((ifa->ifa_flags & IFF_LOOPBACK) != 0)
801			continue;
802		if ((ifa->ifa_flags & IFF_MULTICAST) == 0)
803			continue;
804
805		if (ifa->ifa_addr->sa_family != AF_INET6)
806			continue;
807
808		found = 0;
809		for (i = 0; i < n; i++) {
810			if (strcmp(argv[i], ifa->ifa_name) == 0) {
811				found++;
812				break;
813			}
814		}
815		if (found)
816			continue;
817
818		/* if we find multiple candidates, just warn. */
819		if (n != 0 && dflag > 1)
820			warnx("multiple interfaces found");
821
822		a = (char **)realloc(argv, (n + 1) * sizeof(char **));
823		if (a == NULL)
824			err(1, "realloc");
825		argv = a;
826		argv[n] = strdup(ifa->ifa_name);
827		if (!argv[n])
828			err(1, "malloc");
829		n++;
830		argv[n] = NULL;
831	}
832
833	if (n) {
834		a = (char **)realloc(argv, (n + 1) * sizeof(char **));
835		if (a == NULL)
836			err(1, "realloc");
837		argv = a;
838		argv[n] = NULL;
839
840		if (dflag > 0) {
841			for (i = 0; i < n; i++)
842				warnx("probing %s", argv[i]);
843		}
844	}
845	freeifaddrs(ifap);
846	return argv;
847}
848