xref: /dragonfly/usr.sbin/rwhod/rwhod.c (revision af79c6e5)
1 /*
2  * Copyright (c) 1983, 1993
3  *	The Regents of the University of California.  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. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  * @(#) Copyright (c) 1983, 1993 The Regents of the University of California.  All rights reserved.
34  * @(#)rwhod.c	8.1 (Berkeley) 6/6/93
35  * $FreeBSD: src/usr.sbin/rwhod/rwhod.c,v 1.13.2.2 2000/12/23 15:28:12 iedowse Exp $
36  * $DragonFly: src/usr.sbin/rwhod/rwhod.c,v 1.3 2003/11/03 19:31:43 eirikn Exp $
37  */
38 
39 #include <sys/param.h>
40 #include <sys/socket.h>
41 #include <sys/stat.h>
42 #include <sys/signal.h>
43 #include <sys/ioctl.h>
44 #include <sys/sysctl.h>
45 
46 #include <net/if.h>
47 #include <net/if_dl.h>
48 #include <net/route.h>
49 #include <netinet/in.h>
50 #include <arpa/inet.h>
51 #include <protocols/rwhod.h>
52 
53 #include <ctype.h>
54 #include <err.h>
55 #include <errno.h>
56 #include <fcntl.h>
57 #include <netdb.h>
58 #include <paths.h>
59 #include <stdio.h>
60 #include <stdlib.h>
61 #include <string.h>
62 #include <syslog.h>
63 #include <unistd.h>
64 #include <utmp.h>
65 #include <pwd.h>
66 #include <grp.h>
67 
68 /*
69  * This version of Berkeley's rwhod has been modified to use IP multicast
70  * datagrams, under control of a new command-line option:
71  *
72  *	rwhod -m	causes rwhod to use IP multicast (instead of
73  *			broadcast or unicast) on all interfaces that have
74  *			the IFF_MULTICAST flag set in their "ifnet" structs
75  *			(excluding the loopback interface).  The multicast
76  *			reports are sent with a time-to-live of 1, to prevent
77  *			forwarding beyond the directly-connected subnet(s).
78  *
79  *	rwhod -m <ttl>	causes rwhod to send IP multicast datagrams with a
80  *			time-to-live of <ttl>, via a SINGLE interface rather
81  *			than all interfaces.  <ttl> must be between 0 and
82  *			MAX_MULTICAST_SCOPE, defined below.  Note that "-m 1"
83  *			is different than "-m", in that "-m 1" specifies
84  *			transmission on one interface only.
85  *
86  * When "-m" is used without a <ttl> argument, the program accepts multicast
87  * rwhod reports from all multicast-capable interfaces.  If a <ttl> argument
88  * is given, it accepts multicast reports from only one interface, the one
89  * on which reports are sent (which may be controlled via the host's routing
90  * table).  Regardless of the "-m" option, the program accepts broadcast or
91  * unicast reports from all interfaces.  Thus, this program will hear the
92  * reports of old, non-multicasting rwhods, but, if multicasting is used,
93  * those old rwhods won't hear the reports generated by this program.
94  *
95  *                  -- Steve Deering, Stanford University, February 1989
96  */
97 
98 #define	UNPRIV_USER		"daemon"
99 #define	UNPRIV_GROUP		"daemon"
100 
101 #define NO_MULTICAST		0	  /* multicast modes */
102 #define PER_INTERFACE_MULTICAST	1
103 #define SCOPED_MULTICAST	2
104 
105 #define MAX_MULTICAST_SCOPE	32	  /* "site-wide", by convention */
106 
107 #define INADDR_WHOD_GROUP (u_long)0xe0000103      /* 224.0.1.3 */
108 					  /* (belongs in protocols/rwhod.h) */
109 
110 int			insecure_mode;
111 int			quiet_mode;
112 int			iff_flag = IFF_POINTOPOINT;
113 int			multicast_mode  = NO_MULTICAST;
114 int			multicast_scope;
115 struct sockaddr_in	multicast_addr  = { sizeof multicast_addr, AF_INET };
116 
117 /*
118  * Alarm interval. Don't forget to change the down time check in ruptime
119  * if this is changed.
120  */
121 #define AL_INTERVAL (3 * 60)
122 
123 char	myname[MAXHOSTNAMELEN];
124 
125 /*
126  * We communicate with each neighbor in a list constructed at the time we're
127  * started up.  Neighbors are currently directly connected via a hardware
128  * interface.
129  */
130 struct	neighbor {
131 	struct	neighbor *n_next;
132 	char	*n_name;		/* interface name */
133 	struct	sockaddr *n_addr;		/* who to send to */
134 	int	n_addrlen;		/* size of address */
135 	int	n_flags;		/* should forward?, interface flags */
136 };
137 
138 struct	neighbor *neighbors;
139 struct	whod mywd;
140 struct	servent *sp;
141 int	s, utmpf;
142 
143 #define	WHDRSIZE	(sizeof(mywd) - sizeof(mywd.wd_we))
144 
145 void	 run_as(uid_t *, gid_t *);
146 int	 configure(int);
147 void	 getboottime(int);
148 void	 onalrm(int);
149 void	 quit(char *);
150 void	 rt_xaddrs(caddr_t, caddr_t, struct rt_addrinfo *);
151 int	 verify(char *, int);
152 static void usage(void);
153 #ifdef DEBUG
154 char	*interval(int, char *);
155 void	 Sendto(int, const void *, size_t, int,
156 		     const struct sockaddr *, int);
157 #define	 sendto Sendto
158 #endif
159 
160 int
161 main(argc, argv)
162 	int argc;
163 	char *argv[];
164 {
165 	struct sockaddr_in from;
166 	struct stat st;
167 	char path[64];
168 	int on = 1;
169 	char *cp;
170 	struct sockaddr_in sin;
171 	uid_t unpriv_uid;
172 	gid_t unpriv_gid;
173 
174 	if (getuid())
175 		errx(1, "not super user");
176 
177 	run_as(&unpriv_uid, &unpriv_gid);
178 
179 	argv++; argc--;
180 	while (argc > 0 && *argv[0] == '-') {
181 		if (strcmp(*argv, "-m") == 0) {
182 			if (argc > 1 && isdigit(*(argv + 1)[0])) {
183 				argv++, argc--;
184 				multicast_mode  = SCOPED_MULTICAST;
185 				multicast_scope = atoi(*argv);
186 				if (multicast_scope > MAX_MULTICAST_SCOPE)
187 					errx(1, "ttl must not exceed %u",
188 					MAX_MULTICAST_SCOPE);
189 			}
190 			else multicast_mode = PER_INTERFACE_MULTICAST;
191 		}
192 		else if (strcmp(*argv, "-i") == 0)
193 			insecure_mode = 1;
194 		else if (strcmp(*argv, "-l") == 0)
195 			quiet_mode = 1;
196 		else if (strcmp(*argv, "-p") == 0)
197 			iff_flag = 0;
198 		else
199 			usage();
200 		argv++, argc--;
201 	}
202 	if (argc > 0)
203 		usage();
204 #ifndef DEBUG
205 	daemon(1, 0);
206 #endif
207 	(void) signal(SIGHUP, getboottime);
208 	openlog("rwhod", LOG_PID, LOG_DAEMON);
209 	sp = getservbyname("who", "udp");
210 	if (sp == NULL) {
211 		syslog(LOG_ERR, "udp/who: unknown service");
212 		exit(1);
213 	}
214 	if (chdir(_PATH_RWHODIR) < 0) {
215 		syslog(LOG_ERR, "%s: %m", _PATH_RWHODIR);
216 		exit(1);
217 	}
218 	/*
219 	 * Establish host name as returned by system.
220 	 */
221 	if (gethostname(myname, sizeof(myname) - 1) < 0) {
222 		syslog(LOG_ERR, "gethostname: %m");
223 		exit(1);
224 	}
225 	if ((cp = index(myname, '.')) != NULL)
226 		*cp = '\0';
227 	strncpy(mywd.wd_hostname, myname, sizeof(mywd.wd_hostname) - 1);
228 	mywd.wd_hostname[sizeof(mywd.wd_hostname) - 1] = '\0';
229 	utmpf = open(_PATH_UTMP, O_RDONLY|O_CREAT, 0644);
230 	if (utmpf < 0) {
231 		syslog(LOG_ERR, "%s: %m", _PATH_UTMP);
232 		exit(1);
233 	}
234 	getboottime(0);
235 	if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
236 		syslog(LOG_ERR, "socket: %m");
237 		exit(1);
238 	}
239 	if (setsockopt(s, SOL_SOCKET, SO_BROADCAST, &on, sizeof(on)) < 0) {
240 		syslog(LOG_ERR, "setsockopt SO_BROADCAST: %m");
241 		exit(1);
242 	}
243 	memset(&sin, 0, sizeof(sin));
244 	sin.sin_len = sizeof(sin);
245 	sin.sin_family = AF_INET;
246 	sin.sin_port = sp->s_port;
247 	if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) < 0) {
248 		syslog(LOG_ERR, "bind: %m");
249 		exit(1);
250 	}
251 	setgid(unpriv_gid);
252 	setgroups(1, &unpriv_gid);	/* XXX BOGUS groups[0] = egid */
253 	setuid(unpriv_uid);
254 	if (!configure(s))
255 		exit(1);
256 	if (!quiet_mode) {
257 		signal(SIGALRM, onalrm);
258 		onalrm(0);
259 	}
260 	for (;;) {
261 		struct whod wd;
262 		int cc, whod, len = sizeof(from);
263 
264 		cc = recvfrom(s, (char *)&wd, sizeof(struct whod), 0,
265 			(struct sockaddr *)&from, &len);
266 		if (cc <= 0) {
267 			if (cc < 0 && errno != EINTR)
268 				syslog(LOG_WARNING, "recv: %m");
269 			continue;
270 		}
271 		if (from.sin_port != sp->s_port && !insecure_mode) {
272 			syslog(LOG_WARNING, "%d: bad source port from %s",
273 			    ntohs(from.sin_port), inet_ntoa(from.sin_addr));
274 			continue;
275 		}
276 		if (cc < WHDRSIZE) {
277 			syslog(LOG_WARNING, "short packet from %s",
278 			    inet_ntoa(from.sin_addr));
279 			continue;
280 		}
281 		if (wd.wd_vers != WHODVERSION)
282 			continue;
283 		if (wd.wd_type != WHODTYPE_STATUS)
284 			continue;
285 		if (!verify(wd.wd_hostname, sizeof wd.wd_hostname)) {
286 			syslog(LOG_WARNING, "malformed host name from %s",
287 			    inet_ntoa(from.sin_addr));
288 			continue;
289 		}
290 		(void) snprintf(path, sizeof path, "whod.%s", wd.wd_hostname);
291 		/*
292 		 * Rather than truncating and growing the file each time,
293 		 * use ftruncate if size is less than previous size.
294 		 */
295 		whod = open(path, O_WRONLY | O_CREAT, 0644);
296 		if (whod < 0) {
297 			syslog(LOG_WARNING, "%s: %m", path);
298 			continue;
299 		}
300 #if ENDIAN != BIG_ENDIAN
301 		{
302 			int i, n = (cc - WHDRSIZE)/sizeof(struct whoent);
303 			struct whoent *we;
304 
305 			/* undo header byte swapping before writing to file */
306 			wd.wd_sendtime = ntohl(wd.wd_sendtime);
307 			for (i = 0; i < 3; i++)
308 				wd.wd_loadav[i] = ntohl(wd.wd_loadav[i]);
309 			wd.wd_boottime = ntohl(wd.wd_boottime);
310 			we = wd.wd_we;
311 			for (i = 0; i < n; i++) {
312 				we->we_idle = ntohl(we->we_idle);
313 				we->we_utmp.out_time =
314 				    ntohl(we->we_utmp.out_time);
315 				we++;
316 			}
317 		}
318 #endif
319 		(void) time((time_t *)&wd.wd_recvtime);
320 		(void) write(whod, (char *)&wd, cc);
321 		if (fstat(whod, &st) < 0 || st.st_size > cc)
322 			ftruncate(whod, cc);
323 		(void) close(whod);
324 	}
325 }
326 
327 static void
328 usage()
329 {
330 	fprintf(stderr, "usage: rwhod [-i] [-p] [-l] [-m [ttl]]\n");
331 	exit(1);
332 }
333 
334 void
335 run_as(uid, gid)
336 	uid_t *uid;
337 	gid_t *gid;
338 {
339 	struct passwd *pw;
340 	struct group *gr;
341 
342 	pw = getpwnam(UNPRIV_USER);
343 	if (!pw) {
344 		syslog(LOG_ERR, "getpwnam(%s): %m", UNPRIV_USER);
345 		exit(1);
346 	}
347 	*uid = pw->pw_uid;
348 
349 	gr = getgrnam(UNPRIV_GROUP);
350 	if (!gr) {
351 		syslog(LOG_ERR, "getgrnam(%s): %m", UNPRIV_GROUP);
352 		exit(1);
353 	}
354 	*gid = gr->gr_gid;
355 }
356 
357 /*
358  * Check out host name for unprintables
359  * and other funnies before allowing a file
360  * to be created.  Sorry, but blanks aren't allowed.
361  */
362 int
363 verify(name, maxlen)
364 	register char *name;
365 	register int   maxlen;
366 {
367 	register int size = 0;
368 
369 	while (*name && size < maxlen - 1) {
370 		if (!isascii(*name) || !(isalnum(*name) || ispunct(*name)))
371 			return (0);
372 		name++, size++;
373 	}
374 	*name = '\0';
375 	return (size > 0);
376 }
377 
378 int	utmptime;
379 int	utmpent;
380 int	utmpsize = 0;
381 struct	utmp *utmp;
382 int	alarmcount;
383 
384 void
385 onalrm(signo)
386 	int signo;
387 {
388 	register struct neighbor *np;
389 	register struct whoent *we = mywd.wd_we, *wlast;
390 	register int i;
391 	struct stat stb;
392 	double avenrun[3];
393 	time_t now;
394 	int cc;
395 
396 	now = time(NULL);
397 	if (alarmcount % 10 == 0)
398 		getboottime(0);
399 	alarmcount++;
400 	(void) fstat(utmpf, &stb);
401 	if ((stb.st_mtime != utmptime) || (stb.st_size > utmpsize)) {
402 		utmptime = stb.st_mtime;
403 		if (stb.st_size > utmpsize) {
404 			utmpsize = stb.st_size + 10 * sizeof(struct utmp);
405 			if (utmp)
406 				utmp = (struct utmp *)realloc(utmp, utmpsize);
407 			else
408 				utmp = (struct utmp *)malloc(utmpsize);
409 			if (! utmp) {
410 				syslog(LOG_WARNING, "malloc failed");
411 				utmpsize = 0;
412 				goto done;
413 			}
414 		}
415 		(void) lseek(utmpf, (off_t)0, L_SET);
416 		cc = read(utmpf, (char *)utmp, stb.st_size);
417 		if (cc < 0) {
418 			syslog(LOG_ERR, "read(%s): %m", _PATH_UTMP);
419 			goto done;
420 		}
421 		wlast = &mywd.wd_we[1024 / sizeof(struct whoent) - 1];
422 		utmpent = cc / sizeof(struct utmp);
423 		for (i = 0; i < utmpent; i++)
424 			if (utmp[i].ut_name[0]) {
425 				memcpy(we->we_utmp.out_line, utmp[i].ut_line,
426 				   sizeof(utmp[i].ut_line));
427 				memcpy(we->we_utmp.out_name, utmp[i].ut_name,
428 				   sizeof(utmp[i].ut_name));
429 				we->we_utmp.out_time = htonl(utmp[i].ut_time);
430 				if (we >= wlast)
431 					break;
432 				we++;
433 			}
434 		utmpent = we - mywd.wd_we;
435 	}
436 
437 	/*
438 	 * The test on utmpent looks silly---after all, if no one is
439 	 * logged on, why worry about efficiency?---but is useful on
440 	 * (e.g.) compute servers.
441 	 */
442 	if (utmpent && chdir(_PATH_DEV)) {
443 		syslog(LOG_ERR, "chdir(%s): %m", _PATH_DEV);
444 		exit(1);
445 	}
446 	we = mywd.wd_we;
447 	for (i = 0; i < utmpent; i++) {
448 		if (stat(we->we_utmp.out_line, &stb) >= 0)
449 			we->we_idle = htonl(now - stb.st_atime);
450 		we++;
451 	}
452 	(void)getloadavg(avenrun, sizeof(avenrun)/sizeof(avenrun[0]));
453 	for (i = 0; i < 3; i++)
454 		mywd.wd_loadav[i] = htonl((u_long)(avenrun[i] * 100));
455 	cc = (char *)we - (char *)&mywd;
456 	mywd.wd_sendtime = htonl(time(0));
457 	mywd.wd_vers = WHODVERSION;
458 	mywd.wd_type = WHODTYPE_STATUS;
459 	if (multicast_mode == SCOPED_MULTICAST) {
460 		(void) sendto(s, (char *)&mywd, cc, 0,
461 				(struct sockaddr *)&multicast_addr,
462 				sizeof(multicast_addr));
463 	}
464 	else for (np = neighbors; np != NULL; np = np->n_next) {
465 		if (multicast_mode == PER_INTERFACE_MULTICAST &&
466 		    np->n_flags & IFF_MULTICAST) {
467 			/*
468 			 * Select the outgoing interface for the multicast.
469 			 */
470 			if (setsockopt(s, IPPROTO_IP, IP_MULTICAST_IF,
471 			    &(((struct sockaddr_in *)np->n_addr)->sin_addr),
472 			    sizeof(struct in_addr)) < 0) {
473 				syslog(LOG_ERR,
474 					"setsockopt IP_MULTICAST_IF: %m");
475 				exit(1);
476 			}
477 			(void) sendto(s, (char *)&mywd, cc, 0,
478 				(struct sockaddr *)&multicast_addr,
479 				sizeof(multicast_addr));
480 		} else (void) sendto(s, (char *)&mywd, cc, 0,
481 					np->n_addr, np->n_addrlen);
482 	}
483 	if (utmpent && chdir(_PATH_RWHODIR)) {
484 		syslog(LOG_ERR, "chdir(%s): %m", _PATH_RWHODIR);
485 		exit(1);
486 	}
487 done:
488 	(void) alarm(AL_INTERVAL);
489 }
490 
491 void
492 getboottime(signo)
493 	int signo;
494 {
495 	int mib[2];
496 	size_t size;
497 	struct timeval tm;
498 
499 	mib[0] = CTL_KERN;
500 	mib[1] = KERN_BOOTTIME;
501 	size = sizeof(tm);
502 	if (sysctl(mib, 2, &tm, &size, NULL, 0) == -1) {
503 		syslog(LOG_ERR, "cannot get boottime: %m");
504 		exit(1);
505 	}
506 	mywd.wd_boottime = htonl(tm.tv_sec);
507 }
508 
509 void
510 quit(msg)
511 	char *msg;
512 {
513 	syslog(LOG_ERR, "%s", msg);
514 	exit(1);
515 }
516 
517 #define ROUNDUP(a) \
518 	((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))
519 #define ADVANCE(x, n) (x += ROUNDUP((n)->sa_len))
520 
521 void
522 rt_xaddrs(cp, cplim, rtinfo)
523 	register caddr_t cp, cplim;
524 	register struct rt_addrinfo *rtinfo;
525 {
526 	register struct sockaddr *sa;
527 	register int i;
528 
529 	memset(rtinfo->rti_info, 0, sizeof(rtinfo->rti_info));
530 	for (i = 0; (i < RTAX_MAX) && (cp < cplim); i++) {
531 		if ((rtinfo->rti_addrs & (1 << i)) == 0)
532 			continue;
533 		rtinfo->rti_info[i] = sa = (struct sockaddr *)cp;
534 		ADVANCE(cp, sa);
535 	}
536 }
537 
538 /*
539  * Figure out device configuration and select
540  * networks which deserve status information.
541  */
542 int
543 configure(s)
544 	int s;
545 {
546 	register struct neighbor *np;
547 	register struct if_msghdr *ifm;
548 	register struct ifa_msghdr *ifam;
549 	struct sockaddr_dl *sdl;
550 	size_t needed;
551 	int mib[6], flags = 0, len;
552 	char *buf, *lim, *next;
553 	struct rt_addrinfo info;
554 
555 	if (multicast_mode != NO_MULTICAST) {
556 		multicast_addr.sin_addr.s_addr = htonl(INADDR_WHOD_GROUP);
557 		multicast_addr.sin_port = sp->s_port;
558 	}
559 
560 	if (multicast_mode == SCOPED_MULTICAST) {
561 		struct ip_mreq mreq;
562 		unsigned char ttl;
563 
564 		mreq.imr_multiaddr.s_addr = htonl(INADDR_WHOD_GROUP);
565 		mreq.imr_interface.s_addr = htonl(INADDR_ANY);
566 		if (setsockopt(s, IPPROTO_IP, IP_ADD_MEMBERSHIP,
567 					&mreq, sizeof(mreq)) < 0) {
568 			syslog(LOG_ERR,
569 				"setsockopt IP_ADD_MEMBERSHIP: %m");
570 			return(0);
571 		}
572 		ttl = multicast_scope;
573 		if (setsockopt(s, IPPROTO_IP, IP_MULTICAST_TTL,
574 					&ttl, sizeof(ttl)) < 0) {
575 			syslog(LOG_ERR,
576 				"setsockopt IP_MULTICAST_TTL: %m");
577 			return(0);
578 		}
579 		return(1);
580 	}
581 
582 	mib[0] = CTL_NET;
583 	mib[1] = PF_ROUTE;
584 	mib[2] = 0;
585 	mib[3] = AF_INET;
586 	mib[4] = NET_RT_IFLIST;
587 	mib[5] = 0;
588 	if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0)
589 		quit("route-sysctl-estimate");
590 	if ((buf = malloc(needed)) == NULL)
591 		quit("malloc");
592 	if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0)
593 		quit("actual retrieval of interface table");
594 	lim = buf + needed;
595 
596 	sdl = NULL;		/* XXX just to keep gcc -Wall happy */
597 	for (next = buf; next < lim; next += ifm->ifm_msglen) {
598 		ifm = (struct if_msghdr *)next;
599 		if (ifm->ifm_type == RTM_IFINFO) {
600 			sdl = (struct sockaddr_dl *)(ifm + 1);
601 			flags = ifm->ifm_flags;
602 			continue;
603 		}
604 		if ((flags & IFF_UP) == 0 ||
605 		    (flags & (((multicast_mode == PER_INTERFACE_MULTICAST) ?
606 				IFF_MULTICAST : 0) |
607 				IFF_BROADCAST|iff_flag)) == 0)
608 			continue;
609 		if (ifm->ifm_type != RTM_NEWADDR)
610 			quit("out of sync parsing NET_RT_IFLIST");
611 		ifam = (struct ifa_msghdr *)ifm;
612 		info.rti_addrs = ifam->ifam_addrs;
613 		rt_xaddrs((char *)(ifam + 1), ifam->ifam_msglen + (char *)ifam,
614 			&info);
615 		/* gag, wish we could get rid of Internet dependencies */
616 #define dstaddr	info.rti_info[RTAX_BRD]
617 #define ifaddr info.rti_info[RTAX_IFA]
618 #define IPADDR_SA(x) ((struct sockaddr_in *)(x))->sin_addr.s_addr
619 #define PORT_SA(x) ((struct sockaddr_in *)(x))->sin_port
620 		if (dstaddr == 0 || dstaddr->sa_family != AF_INET)
621 			continue;
622 		PORT_SA(dstaddr) = sp->s_port;
623 		for (np = neighbors; np != NULL; np = np->n_next)
624 			if (memcmp(sdl->sdl_data, np->n_name,
625 				   sdl->sdl_nlen) == 0 &&
626 			    IPADDR_SA(np->n_addr) == IPADDR_SA(dstaddr))
627 				break;
628 		if (np != NULL)
629 			continue;
630 		len = sizeof(*np) + dstaddr->sa_len + sdl->sdl_nlen + 1;
631 		np = (struct neighbor *)malloc(len);
632 		if (np == NULL)
633 			quit("malloc of neighbor structure");
634 		memset(np, 0, len);
635 		np->n_flags = flags;
636 		np->n_addr = (struct sockaddr *)(np + 1);
637 		np->n_addrlen = dstaddr->sa_len;
638 		np->n_name = np->n_addrlen + (char *)np->n_addr;
639 		memcpy((char *)np->n_addr, (char *)dstaddr, np->n_addrlen);
640 		memcpy(np->n_name, sdl->sdl_data, sdl->sdl_nlen);
641 		if (multicast_mode == PER_INTERFACE_MULTICAST &&
642 		    (flags & IFF_MULTICAST) &&
643 		   !(flags & IFF_LOOPBACK)) {
644 			struct ip_mreq mreq;
645 
646 			memcpy((char *)np->n_addr, (char *)ifaddr,
647 				np->n_addrlen);
648 			mreq.imr_multiaddr.s_addr = htonl(INADDR_WHOD_GROUP);
649 			mreq.imr_interface.s_addr =
650 			  ((struct sockaddr_in *)np->n_addr)->sin_addr.s_addr;
651 			if (setsockopt(s, IPPROTO_IP, IP_ADD_MEMBERSHIP,
652 						&mreq, sizeof(mreq)) < 0) {
653 				syslog(LOG_ERR,
654 				    "setsockopt IP_ADD_MEMBERSHIP: %m");
655 #if 0
656 				/* Fall back to broadcast on this if. */
657 				np->n_flags &= ~IFF_MULTICAST;
658 #else
659 				free((char *)np);
660 				continue;
661 #endif
662 			}
663 		}
664 		np->n_next = neighbors;
665 		neighbors = np;
666 	}
667 	free(buf);
668 	return (1);
669 }
670 
671 #ifdef DEBUG
672 void
673 Sendto(s, buf, cc, flags, to, tolen)
674 	int s;
675 	const void *buf;
676 	size_t cc;
677 	int flags;
678 	const struct sockaddr *to;
679 	int tolen;
680 {
681 	register struct whod *w = (struct whod *)buf;
682 	register struct whoent *we;
683 	struct sockaddr_in *sin = (struct sockaddr_in *)to;
684 
685 	printf("sendto %x.%d\n", ntohl(sin->sin_addr.s_addr),
686 				 ntohs(sin->sin_port));
687 	printf("hostname %s %s\n", w->wd_hostname,
688 	   interval(ntohl(w->wd_sendtime) - ntohl(w->wd_boottime), "  up"));
689 	printf("load %4.2f, %4.2f, %4.2f\n",
690 	    ntohl(w->wd_loadav[0]) / 100.0, ntohl(w->wd_loadav[1]) / 100.0,
691 	    ntohl(w->wd_loadav[2]) / 100.0);
692 	cc -= WHDRSIZE;
693 	for (we = w->wd_we, cc /= sizeof(struct whoent); cc > 0; cc--, we++) {
694 		time_t t = ntohl(we->we_utmp.out_time);
695 		printf("%-8.8s %s:%s %.12s",
696 			we->we_utmp.out_name,
697 			w->wd_hostname, we->we_utmp.out_line,
698 			ctime(&t)+4);
699 		we->we_idle = ntohl(we->we_idle) / 60;
700 		if (we->we_idle) {
701 			if (we->we_idle >= 100*60)
702 				we->we_idle = 100*60 - 1;
703 			if (we->we_idle >= 60)
704 				printf(" %2d", we->we_idle / 60);
705 			else
706 				printf("   ");
707 			printf(":%02d", we->we_idle % 60);
708 		}
709 		printf("\n");
710 	}
711 }
712 
713 char *
714 interval(time, updown)
715 	int time;
716 	char *updown;
717 {
718 	static char resbuf[32];
719 	int days, hours, minutes;
720 
721 	if (time < 0 || time > 3*30*24*60*60) {
722 		(void) sprintf(resbuf, "   %s ??:??", updown);
723 		return (resbuf);
724 	}
725 	minutes = (time + 59) / 60;		/* round to minutes */
726 	hours = minutes / 60; minutes %= 60;
727 	days = hours / 24; hours %= 24;
728 	if (days)
729 		(void) sprintf(resbuf, "%s %2d+%02d:%02d",
730 		    updown, days, hours, minutes);
731 	else
732 		(void) sprintf(resbuf, "%s    %2d:%02d",
733 		    updown, hours, minutes);
734 	return (resbuf);
735 }
736 #endif
737