xref: /freebsd/usr.sbin/rwhod/rwhod.c (revision a8445737e740901f5f2c8d24c12ef7fc8b00134e)
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 
34 #ifndef lint
35 static const char copyright[] =
36 "@(#) Copyright (c) 1983, 1993\n\
37 	The Regents of the University of California.  All rights reserved.\n";
38 #endif /* not lint */
39 
40 #ifndef lint
41 #if 0
42 static char sccsid[] = "@(#)rwhod.c	8.1 (Berkeley) 6/6/93";
43 #endif
44 static const char rcsid[] =
45 	"$Id$";
46 #endif /* not lint */
47 
48 #include <sys/param.h>
49 #include <sys/socket.h>
50 #include <sys/stat.h>
51 #include <sys/signal.h>
52 #include <sys/ioctl.h>
53 #include <sys/sysctl.h>
54 
55 #include <net/if.h>
56 #include <net/if_dl.h>
57 #include <net/route.h>
58 #include <netinet/in.h>
59 #include <protocols/rwhod.h>
60 
61 #include <ctype.h>
62 #include <err.h>
63 #include <errno.h>
64 #include <fcntl.h>
65 #include <netdb.h>
66 #include <paths.h>
67 #include <stdio.h>
68 #include <stdlib.h>
69 #include <string.h>
70 #include <syslog.h>
71 #include <unistd.h>
72 #include <utmp.h>
73 #include <pwd.h>
74 #include <grp.h>
75 
76 /*
77  * This version of Berkeley's rwhod has been modified to use IP multicast
78  * datagrams, under control of a new command-line option:
79  *
80  *	rwhod -m	causes rwhod to use IP multicast (instead of
81  *			broadcast or unicast) on all interfaces that have
82  *			the IFF_MULTICAST flag set in their "ifnet" structs
83  *			(excluding the loopback interface).  The multicast
84  *			reports are sent with a time-to-live of 1, to prevent
85  *			forwarding beyond the directly-connected subnet(s).
86  *
87  *	rwhod -m <ttl>	causes rwhod to send IP multicast datagrams with a
88  *			time-to-live of <ttl>, via a SINGLE interface rather
89  *			than all interfaces.  <ttl> must be between 0 and
90  *			MAX_MULTICAST_SCOPE, defined below.  Note that "-m 1"
91  *			is different than "-m", in that "-m 1" specifies
92  *			transmission on one interface only.
93  *
94  * When "-m" is used without a <ttl> argument, the program accepts multicast
95  * rwhod reports from all multicast-capable interfaces.  If a <ttl> argument
96  * is given, it accepts multicast reports from only one interface, the one
97  * on which reports are sent (which may be controlled via the host's routing
98  * table).  Regardless of the "-m" option, the program accepts broadcast or
99  * unicast reports from all interfaces.  Thus, this program will hear the
100  * reports of old, non-multicasting rwhods, but, if multicasting is used,
101  * those old rwhods won't hear the reports generated by this program.
102  *
103  *                  -- Steve Deering, Stanford University, February 1989
104  */
105 
106 #define	UNPRIV_USER		"daemon"
107 #define	UNPRIV_GROUP		"daemon"
108 
109 #define NO_MULTICAST		0	  /* multicast modes */
110 #define PER_INTERFACE_MULTICAST	1
111 #define SCOPED_MULTICAST	2
112 
113 #define MAX_MULTICAST_SCOPE	32	  /* "site-wide", by convention */
114 
115 #define INADDR_WHOD_GROUP (u_long)0xe0000103      /* 224.0.1.3 */
116 					  /* (belongs in protocols/rwhod.h) */
117 
118 int			multicast_mode  = NO_MULTICAST;
119 int			multicast_scope;
120 struct sockaddr_in	multicast_addr  = { sizeof multicast_addr, AF_INET };
121 
122 /*
123  * Alarm interval. Don't forget to change the down time check in ruptime
124  * if this is changed.
125  */
126 #define AL_INTERVAL (3 * 60)
127 
128 char	myname[MAXHOSTNAMELEN];
129 
130 /*
131  * We communicate with each neighbor in a list constructed at the time we're
132  * started up.  Neighbors are currently directly connected via a hardware
133  * interface.
134  */
135 struct	neighbor {
136 	struct	neighbor *n_next;
137 	char	*n_name;		/* interface name */
138 	struct	sockaddr *n_addr;		/* who to send to */
139 	int	n_addrlen;		/* size of address */
140 	int	n_flags;		/* should forward?, interface flags */
141 };
142 
143 struct	neighbor *neighbors;
144 struct	whod mywd;
145 struct	servent *sp;
146 int	s, utmpf;
147 
148 #define	WHDRSIZE	(sizeof(mywd) - sizeof(mywd.wd_we))
149 
150 void	 run_as __P((uid_t *, gid_t *));
151 int	 configure __P((int));
152 void	 getboottime __P((int));
153 void	 onalrm __P((int));
154 void	 quit __P((char *));
155 void	 rt_xaddrs __P((caddr_t, caddr_t, struct rt_addrinfo *));
156 int	 verify __P((char *, int));
157 static void usage __P((void));
158 #ifdef DEBUG
159 char	*interval __P((int, char *));
160 void	 Sendto __P((int, const void *, size_t, int,
161 		     const struct sockaddr *, int));
162 #define	 sendto Sendto
163 #endif
164 
165 int
166 main(argc, argv)
167 	int argc;
168 	char *argv[];
169 {
170 	struct sockaddr_in from;
171 	struct stat st;
172 	char path[64];
173 	int on = 1;
174 	char *cp;
175 	struct sockaddr_in sin;
176 	uid_t unpriv_uid;
177 	gid_t unpriv_gid;
178 
179 	if (getuid())
180 		errx(1, "not super user");
181 
182 	run_as(&unpriv_uid, &unpriv_gid);
183 
184 	argv++; argc--;
185 	while (argc > 0 && *argv[0] == '-') {
186 		if (strcmp(*argv, "-m") == 0) {
187 			if (argc > 1 && isdigit(*(argv + 1)[0])) {
188 				argv++, argc--;
189 				multicast_mode  = SCOPED_MULTICAST;
190 				multicast_scope = atoi(*argv);
191 				if (multicast_scope > MAX_MULTICAST_SCOPE)
192 					errx(1, "ttl must not exceed %u",
193 					MAX_MULTICAST_SCOPE);
194 			}
195 			else multicast_mode = PER_INTERFACE_MULTICAST;
196 		}
197 		else
198 			usage();
199 		argv++, argc--;
200 	}
201 	if (argc > 0)
202 		usage();
203 #ifndef DEBUG
204 	daemon(1, 0);
205 #endif
206 	(void) signal(SIGHUP, getboottime);
207 	openlog("rwhod", LOG_PID, LOG_DAEMON);
208 	sp = getservbyname("who", "udp");
209 	if (sp == NULL) {
210 		syslog(LOG_ERR, "rwhod: udp/who: unknown service\n");
211 		exit(1);
212 	}
213 	if (chdir(_PATH_RWHODIR) < 0) {
214 		syslog(LOG_ERR, "rwhod: %s: %m\n", _PATH_RWHODIR);
215 		exit(1);
216 	}
217 	/*
218 	 * Establish host name as returned by system.
219 	 */
220 	if (gethostname(myname, sizeof(myname) - 1) < 0) {
221 		syslog(LOG_ERR, "gethostname: %m");
222 		exit(1);
223 	}
224 	if ((cp = index(myname, '.')) != NULL)
225 		*cp = '\0';
226 	strncpy(mywd.wd_hostname, myname, sizeof(mywd.wd_hostname) - 1);
227 	mywd.wd_hostname[sizeof(mywd.wd_hostname) - 1] = '\0';
228 	utmpf = open(_PATH_UTMP, O_RDONLY|O_CREAT, 0644);
229 	if (utmpf < 0) {
230 		syslog(LOG_ERR, "%s: %m", _PATH_UTMP);
231 		exit(1);
232 	}
233 	getboottime(0);
234 	if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
235 		syslog(LOG_ERR, "socket: %m");
236 		exit(1);
237 	}
238 	if (setsockopt(s, SOL_SOCKET, SO_BROADCAST, &on, sizeof(on)) < 0) {
239 		syslog(LOG_ERR, "setsockopt SO_BROADCAST: %m");
240 		exit(1);
241 	}
242 	memset(&sin, 0, sizeof(sin));
243 	sin.sin_len = sizeof(sin);
244 	sin.sin_family = AF_INET;
245 	sin.sin_port = sp->s_port;
246 	if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) < 0) {
247 		syslog(LOG_ERR, "bind: %m");
248 		exit(1);
249 	}
250 	setgid(unpriv_gid);
251 	setgroups(1, &unpriv_gid);	/* XXX BOGUS groups[0] = egid */
252 	setuid(unpriv_uid);
253 	if (!configure(s))
254 		exit(1);
255 	signal(SIGALRM, onalrm);
256 	onalrm(0);
257 	for (;;) {
258 		struct whod wd;
259 		int cc, whod, len = sizeof(from);
260 
261 		cc = recvfrom(s, (char *)&wd, sizeof(struct whod), 0,
262 			(struct sockaddr *)&from, &len);
263 		if (cc <= 0) {
264 			if (cc < 0 && errno != EINTR)
265 				syslog(LOG_WARNING, "recv: %m");
266 			continue;
267 		}
268 		if (from.sin_port != sp->s_port) {
269 			syslog(LOG_WARNING, "%d: bad from port",
270 				ntohs(from.sin_port));
271 			continue;
272 		}
273 		if (wd.wd_vers != WHODVERSION)
274 			continue;
275 		if (wd.wd_type != WHODTYPE_STATUS)
276 			continue;
277 		if (!verify(wd.wd_hostname, sizeof wd.wd_hostname)) {
278 			syslog(LOG_WARNING, "malformed host name from %x",
279 				from.sin_addr);
280 			continue;
281 		}
282 		(void) snprintf(path, sizeof path, "whod.%s", wd.wd_hostname);
283 		/*
284 		 * Rather than truncating and growing the file each time,
285 		 * use ftruncate if size is less than previous size.
286 		 */
287 		whod = open(path, O_WRONLY | O_CREAT, 0644);
288 		if (whod < 0) {
289 			syslog(LOG_WARNING, "%s: %m", path);
290 			continue;
291 		}
292 #if ENDIAN != BIG_ENDIAN
293 		{
294 			int i, n = (cc - WHDRSIZE)/sizeof(struct whoent);
295 			struct whoent *we;
296 
297 			/* undo header byte swapping before writing to file */
298 			wd.wd_sendtime = ntohl(wd.wd_sendtime);
299 			for (i = 0; i < 3; i++)
300 				wd.wd_loadav[i] = ntohl(wd.wd_loadav[i]);
301 			wd.wd_boottime = ntohl(wd.wd_boottime);
302 			we = wd.wd_we;
303 			for (i = 0; i < n; i++) {
304 				we->we_idle = ntohl(we->we_idle);
305 				we->we_utmp.out_time =
306 				    ntohl(we->we_utmp.out_time);
307 				we++;
308 			}
309 		}
310 #endif
311 		(void) time((time_t *)&wd.wd_recvtime);
312 		(void) write(whod, (char *)&wd, cc);
313 		if (fstat(whod, &st) < 0 || st.st_size > cc)
314 			ftruncate(whod, cc);
315 		(void) close(whod);
316 	}
317 }
318 
319 static void
320 usage()
321 {
322 	fprintf(stderr, "usage: rwhod [-m [ttl]]\n");
323 	exit(1);
324 }
325 
326 void
327 run_as(uid, gid)
328 	uid_t *uid;
329 	gid_t *gid;
330 {
331 	struct passwd *pw;
332 	struct group *gr;
333 
334 	pw = getpwnam(UNPRIV_USER);
335 	if (!pw) {
336 		syslog(LOG_ERR, "getpwnam(%s): %m", UNPRIV_USER);
337 		exit(1);
338 	}
339 	*uid = pw->pw_uid;
340 
341 	gr = getgrnam(UNPRIV_GROUP);
342 	if (!gr) {
343 		syslog(LOG_ERR, "getgrnam(%s): %m", UNPRIV_GROUP);
344 		exit(1);
345 	}
346 	*gid = gr->gr_gid;
347 }
348 
349 /*
350  * Check out host name for unprintables
351  * and other funnies before allowing a file
352  * to be created.  Sorry, but blanks aren't allowed.
353  */
354 int
355 verify(name, maxlen)
356 	register char *name;
357 	register int   maxlen;
358 {
359 	register int size = 0;
360 
361 	while (*name && size < maxlen - 1) {
362 		if (!isascii(*name) || !(isalnum(*name) || ispunct(*name)))
363 			return (0);
364 		name++, size++;
365 	}
366 	*name = '\0';
367 	return (size > 0);
368 }
369 
370 int	utmptime;
371 int	utmpent;
372 int	utmpsize = 0;
373 struct	utmp *utmp;
374 int	alarmcount;
375 
376 void
377 onalrm(signo)
378 	int signo;
379 {
380 	register struct neighbor *np;
381 	register struct whoent *we = mywd.wd_we, *wlast;
382 	register int i;
383 	struct stat stb;
384 	double avenrun[3];
385 	time_t now;
386 	int cc;
387 
388 	now = time(NULL);
389 	if (alarmcount % 10 == 0)
390 		getboottime(0);
391 	alarmcount++;
392 	(void) fstat(utmpf, &stb);
393 	if ((stb.st_mtime != utmptime) || (stb.st_size > utmpsize)) {
394 		utmptime = stb.st_mtime;
395 		if (stb.st_size > utmpsize) {
396 			utmpsize = stb.st_size + 10 * sizeof(struct utmp);
397 			if (utmp)
398 				utmp = (struct utmp *)realloc(utmp, utmpsize);
399 			else
400 				utmp = (struct utmp *)malloc(utmpsize);
401 			if (! utmp) {
402 				syslog(LOG_WARNING, "malloc failed");
403 				utmpsize = 0;
404 				goto done;
405 			}
406 		}
407 		(void) lseek(utmpf, (off_t)0, L_SET);
408 		cc = read(utmpf, (char *)utmp, stb.st_size);
409 		if (cc < 0) {
410 			syslog(LOG_ERR, "read(%s): %m", _PATH_UTMP);
411 			goto done;
412 		}
413 		wlast = &mywd.wd_we[1024 / sizeof(struct whoent) - 1];
414 		utmpent = cc / sizeof(struct utmp);
415 		for (i = 0; i < utmpent; i++)
416 			if (utmp[i].ut_name[0]) {
417 				memcpy(we->we_utmp.out_line, utmp[i].ut_line,
418 				   sizeof(utmp[i].ut_line));
419 				memcpy(we->we_utmp.out_name, utmp[i].ut_name,
420 				   sizeof(utmp[i].ut_name));
421 				we->we_utmp.out_time = htonl(utmp[i].ut_time);
422 				if (we >= wlast)
423 					break;
424 				we++;
425 			}
426 		utmpent = we - mywd.wd_we;
427 	}
428 
429 	/*
430 	 * The test on utmpent looks silly---after all, if no one is
431 	 * logged on, why worry about efficiency?---but is useful on
432 	 * (e.g.) compute servers.
433 	 */
434 	if (utmpent && chdir(_PATH_DEV)) {
435 		syslog(LOG_ERR, "chdir(%s): %m", _PATH_DEV);
436 		exit(1);
437 	}
438 	we = mywd.wd_we;
439 	for (i = 0; i < utmpent; i++) {
440 		if (stat(we->we_utmp.out_line, &stb) >= 0)
441 			we->we_idle = htonl(now - stb.st_atime);
442 		we++;
443 	}
444 	(void)getloadavg(avenrun, sizeof(avenrun)/sizeof(avenrun[0]));
445 	for (i = 0; i < 3; i++)
446 		mywd.wd_loadav[i] = htonl((u_long)(avenrun[i] * 100));
447 	cc = (char *)we - (char *)&mywd;
448 	mywd.wd_sendtime = htonl(time(0));
449 	mywd.wd_vers = WHODVERSION;
450 	mywd.wd_type = WHODTYPE_STATUS;
451 	if (multicast_mode == SCOPED_MULTICAST) {
452 		(void) sendto(s, (char *)&mywd, cc, 0,
453 				(struct sockaddr *)&multicast_addr,
454 				sizeof(multicast_addr));
455 	}
456 	else for (np = neighbors; np != NULL; np = np->n_next) {
457 		if (multicast_mode == PER_INTERFACE_MULTICAST &&
458 		    np->n_flags & IFF_MULTICAST) {
459 			/*
460 			 * Select the outgoing interface for the multicast.
461 			 */
462 			if (setsockopt(s, IPPROTO_IP, IP_MULTICAST_IF,
463 			    &(((struct sockaddr_in *)np->n_addr)->sin_addr),
464 			    sizeof(struct in_addr)) < 0) {
465 				syslog(LOG_ERR,
466 					"setsockopt IP_MULTICAST_IF: %m");
467 				exit(1);
468 			}
469 			(void) sendto(s, (char *)&mywd, cc, 0,
470 				(struct sockaddr *)&multicast_addr,
471 				sizeof(multicast_addr));
472 		} else (void) sendto(s, (char *)&mywd, cc, 0,
473 					np->n_addr, np->n_addrlen);
474 	}
475 	if (utmpent && chdir(_PATH_RWHODIR)) {
476 		syslog(LOG_ERR, "chdir(%s): %m", _PATH_RWHODIR);
477 		exit(1);
478 	}
479 done:
480 	(void) alarm(AL_INTERVAL);
481 }
482 
483 void
484 getboottime(signo)
485 	int signo;
486 {
487 	int mib[2];
488 	size_t size;
489 	struct timeval tm;
490 
491 	mib[0] = CTL_KERN;
492 	mib[1] = KERN_BOOTTIME;
493 	size = sizeof(tm);
494 	if (sysctl(mib, 2, &tm, &size, NULL, 0) == -1) {
495 		syslog(LOG_ERR, "cannot get boottime: %m");
496 		exit(1);
497 	}
498 	mywd.wd_boottime = htonl(tm.tv_sec);
499 }
500 
501 void
502 quit(msg)
503 	char *msg;
504 {
505 	syslog(LOG_ERR, msg);
506 	exit(1);
507 }
508 
509 #define ROUNDUP(a) \
510 	((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))
511 #define ADVANCE(x, n) (x += ROUNDUP((n)->sa_len))
512 
513 void
514 rt_xaddrs(cp, cplim, rtinfo)
515 	register caddr_t cp, cplim;
516 	register struct rt_addrinfo *rtinfo;
517 {
518 	register struct sockaddr *sa;
519 	register int i;
520 
521 	memset(rtinfo->rti_info, 0, sizeof(rtinfo->rti_info));
522 	for (i = 0; (i < RTAX_MAX) && (cp < cplim); i++) {
523 		if ((rtinfo->rti_addrs & (1 << i)) == 0)
524 			continue;
525 		rtinfo->rti_info[i] = sa = (struct sockaddr *)cp;
526 		ADVANCE(cp, sa);
527 	}
528 }
529 
530 /*
531  * Figure out device configuration and select
532  * networks which deserve status information.
533  */
534 int
535 configure(s)
536 	int s;
537 {
538 	register struct neighbor *np;
539 	register struct if_msghdr *ifm;
540 	register struct ifa_msghdr *ifam;
541 	struct sockaddr_dl *sdl;
542 	size_t needed;
543 	int mib[6], flags = 0, len;
544 	char *buf, *lim, *next;
545 	struct rt_addrinfo info;
546 
547 	if (multicast_mode != NO_MULTICAST) {
548 		multicast_addr.sin_addr.s_addr = htonl(INADDR_WHOD_GROUP);
549 		multicast_addr.sin_port = sp->s_port;
550 	}
551 
552 	if (multicast_mode == SCOPED_MULTICAST) {
553 		struct ip_mreq mreq;
554 		unsigned char ttl;
555 
556 		mreq.imr_multiaddr.s_addr = htonl(INADDR_WHOD_GROUP);
557 		mreq.imr_interface.s_addr = htonl(INADDR_ANY);
558 		if (setsockopt(s, IPPROTO_IP, IP_ADD_MEMBERSHIP,
559 					&mreq, sizeof(mreq)) < 0) {
560 			syslog(LOG_ERR,
561 				"setsockopt IP_ADD_MEMBERSHIP: %m");
562 			return(0);
563 		}
564 		ttl = multicast_scope;
565 		if (setsockopt(s, IPPROTO_IP, IP_MULTICAST_TTL,
566 					&ttl, sizeof(ttl)) < 0) {
567 			syslog(LOG_ERR,
568 				"setsockopt IP_MULTICAST_TTL: %m");
569 			return(0);
570 		}
571 		return(1);
572 	}
573 
574 	mib[0] = CTL_NET;
575 	mib[1] = PF_ROUTE;
576 	mib[2] = 0;
577 	mib[3] = AF_INET;
578 	mib[4] = NET_RT_IFLIST;
579 	mib[5] = 0;
580 	if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0)
581 		quit("route-sysctl-estimate");
582 	if ((buf = malloc(needed)) == NULL)
583 		quit("malloc");
584 	if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0)
585 		quit("actual retrieval of interface table");
586 	lim = buf + needed;
587 
588 	sdl = NULL;		/* XXX just to keep gcc -Wall happy */
589 	for (next = buf; next < lim; next += ifm->ifm_msglen) {
590 		ifm = (struct if_msghdr *)next;
591 		if (ifm->ifm_type == RTM_IFINFO) {
592 			sdl = (struct sockaddr_dl *)(ifm + 1);
593 			flags = ifm->ifm_flags;
594 			continue;
595 		}
596 		if ((flags & IFF_UP) == 0 ||
597 		    (flags & (((multicast_mode == PER_INTERFACE_MULTICAST) ?
598 				IFF_MULTICAST : 0) |
599 				IFF_BROADCAST|IFF_POINTOPOINT)) == 0)
600 			continue;
601 		if (ifm->ifm_type != RTM_NEWADDR)
602 			quit("out of sync parsing NET_RT_IFLIST");
603 		ifam = (struct ifa_msghdr *)ifm;
604 		info.rti_addrs = ifam->ifam_addrs;
605 		rt_xaddrs((char *)(ifam + 1), ifam->ifam_msglen + (char *)ifam,
606 			&info);
607 		/* gag, wish we could get rid of Internet dependencies */
608 #define dstaddr	info.rti_info[RTAX_BRD]
609 #define ifaddr info.rti_info[RTAX_IFA]
610 #define IPADDR_SA(x) ((struct sockaddr_in *)(x))->sin_addr.s_addr
611 #define PORT_SA(x) ((struct sockaddr_in *)(x))->sin_port
612 		if (dstaddr == 0 || dstaddr->sa_family != AF_INET)
613 			continue;
614 		PORT_SA(dstaddr) = sp->s_port;
615 		for (np = neighbors; np != NULL; np = np->n_next)
616 			if (memcmp(sdl->sdl_data, np->n_name,
617 				   sdl->sdl_nlen) == 0 &&
618 			    IPADDR_SA(np->n_addr) == IPADDR_SA(dstaddr))
619 				break;
620 		if (np != NULL)
621 			continue;
622 		len = sizeof(*np) + dstaddr->sa_len + sdl->sdl_nlen + 1;
623 		np = (struct neighbor *)malloc(len);
624 		if (np == NULL)
625 			quit("malloc of neighbor structure");
626 		memset(np, 0, len);
627 		np->n_flags = flags;
628 		np->n_addr = (struct sockaddr *)(np + 1);
629 		np->n_addrlen = dstaddr->sa_len;
630 		np->n_name = np->n_addrlen + (char *)np->n_addr;
631 		memcpy((char *)np->n_addr, (char *)dstaddr, np->n_addrlen);
632 		memcpy(np->n_name, sdl->sdl_data, sdl->sdl_nlen);
633 		if (multicast_mode == PER_INTERFACE_MULTICAST &&
634 		    (flags & IFF_MULTICAST) &&
635 		   !(flags & IFF_LOOPBACK)) {
636 			struct ip_mreq mreq;
637 
638 			memcpy((char *)np->n_addr, (char *)ifaddr,
639 				np->n_addrlen);
640 			mreq.imr_multiaddr.s_addr = htonl(INADDR_WHOD_GROUP);
641 			mreq.imr_interface.s_addr =
642 			  ((struct sockaddr_in *)np->n_addr)->sin_addr.s_addr;
643 			if (setsockopt(s, IPPROTO_IP, IP_ADD_MEMBERSHIP,
644 						&mreq, sizeof(mreq)) < 0) {
645 				syslog(LOG_ERR,
646 				    "setsockopt IP_ADD_MEMBERSHIP: %m");
647 #if 0
648 				/* Fall back to broadcast on this if. */
649 				np->n_flags &= ~IFF_MULTICAST;
650 #else
651 				free((char *)np);
652 				continue;
653 #endif
654 			}
655 		}
656 		np->n_next = neighbors;
657 		neighbors = np;
658 	}
659 	free(buf);
660 	return (1);
661 }
662 
663 #ifdef DEBUG
664 void
665 Sendto(s, buf, cc, flags, to, tolen)
666 	int s;
667 	const void *buf;
668 	size_t cc;
669 	int flags;
670 	const struct sockaddr *to;
671 	int tolen;
672 {
673 	register struct whod *w = (struct whod *)buf;
674 	register struct whoent *we;
675 	struct sockaddr_in *sin = (struct sockaddr_in *)to;
676 
677 	printf("sendto %x.%d\n", ntohl(sin->sin_addr.s_addr),
678 				 ntohs(sin->sin_port));
679 	printf("hostname %s %s\n", w->wd_hostname,
680 	   interval(ntohl(w->wd_sendtime) - ntohl(w->wd_boottime), "  up"));
681 	printf("load %4.2f, %4.2f, %4.2f\n",
682 	    ntohl(w->wd_loadav[0]) / 100.0, ntohl(w->wd_loadav[1]) / 100.0,
683 	    ntohl(w->wd_loadav[2]) / 100.0);
684 	cc -= WHDRSIZE;
685 	for (we = w->wd_we, cc /= sizeof(struct whoent); cc > 0; cc--, we++) {
686 		time_t t = ntohl(we->we_utmp.out_time);
687 		printf("%-8.8s %s:%s %.12s",
688 			we->we_utmp.out_name,
689 			w->wd_hostname, we->we_utmp.out_line,
690 			ctime(&t)+4);
691 		we->we_idle = ntohl(we->we_idle) / 60;
692 		if (we->we_idle) {
693 			if (we->we_idle >= 100*60)
694 				we->we_idle = 100*60 - 1;
695 			if (we->we_idle >= 60)
696 				printf(" %2d", we->we_idle / 60);
697 			else
698 				printf("   ");
699 			printf(":%02d", we->we_idle % 60);
700 		}
701 		printf("\n");
702 	}
703 }
704 
705 char *
706 interval(time, updown)
707 	int time;
708 	char *updown;
709 {
710 	static char resbuf[32];
711 	int days, hours, minutes;
712 
713 	if (time < 0 || time > 3*30*24*60*60) {
714 		(void) sprintf(resbuf, "   %s ??:??", updown);
715 		return (resbuf);
716 	}
717 	minutes = (time + 59) / 60;		/* round to minutes */
718 	hours = minutes / 60; minutes %= 60;
719 	days = hours / 24; hours %= 24;
720 	if (days)
721 		(void) sprintf(resbuf, "%s %2d+%02d:%02d",
722 		    updown, days, hours, minutes);
723 	else
724 		(void) sprintf(resbuf, "%s    %2d:%02d",
725 		    updown, hours, minutes);
726 	return (resbuf);
727 }
728 #endif
729