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      1 /*
      2  * CDDL HEADER START
      3  *
      4  * The contents of this file are subject to the terms of the
      5  * Common Development and Distribution License, Version 1.0 only
      6  * (the "License").  You may not use this file except in compliance
      7  * with the License.
      8  *
      9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
     10  * or http://www.opensolaris.org/os/licensing.
     11  * See the License for the specific language governing permissions
     12  * and limitations under the License.
     13  *
     14  * When distributing Covered Code, include this CDDL HEADER in each
     15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
     16  * If applicable, add the following below this CDDL HEADER, with the
     17  * fields enclosed by brackets "[]" replaced with your own identifying
     18  * information: Portions Copyright [yyyy] [name of copyright owner]
     19  *
     20  * CDDL HEADER END
     21  */
     22 /*
     23  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
     24  * Use is subject to license terms.
     25  */
     26 
     27 /*	Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T	*/
     28 /*	  All Rights Reserved  	*/
     29 
     30 /*
     31  * Portions of this source code were derived from Berkeley 4.3 BSD
     32  * under license from the Regents of the University of California.
     33  */
     34 
     35 #pragma ident	"%Z%%M%	%I%	%E% SMI"
     36 
     37 #include <sys/types.h>
     38 #include <sys/param.h>
     39 #include <sys/socket.h>
     40 #include <sys/sockio.h>
     41 #include <sys/stat.h>
     42 #include <sys/ioctl.h>
     43 #include <sys/file.h>
     44 #include <sys/loadavg.h>
     45 
     46 #include <net/if.h>
     47 #include <netinet/in.h>
     48 
     49 #include <stdio.h>
     50 #include <signal.h>
     51 #include <errno.h>
     52 #include <utmpx.h>
     53 #include <ctype.h>
     54 #include <netdb.h>
     55 #include <syslog.h>
     56 #include <fcntl.h>
     57 #include <sys/isa_defs.h>	/* for ENDIAN defines */
     58 #include <arpa/inet.h>
     59 #include <protocols/rwhod.h>
     60 
     61 #include <strings.h>
     62 #include <stdlib.h>
     63 #include <unistd.h>
     64 
     65 /*
     66  * This version of Berkeley's rwhod has been modified to use IP multicast
     67  * datagrams, under control of a new command-line option:
     68  *
     69  *	rwhod -m	causes rwhod to use IP multicast (instead of
     70  *			broadcast or unicast) on all interfaces that have
     71  *			the IFF_MULTICAST flag set in their "ifnet" structs
     72  *			(excluding the loopback interface).  The multicast
     73  *			reports are sent with a time-to-live of 1, to prevent
     74  *			forwarding beyond the directly-connected subnet(s).
     75  *
     76  *	rwhod -m <ttl>	causes rwhod to send IP multicast datagrams with a
     77  *			time-to-live of <ttl>, via a SINGLE interface rather
     78  *			than all interfaces.  <ttl> must be between 0 and
     79  *			MAX_MULTICAST_SCOPE, defined below.  Note that "-m 1"
     80  *			is different than "-m", in that "-m 1" specifies
     81  *			transmission on one interface only.
     82  *
     83  * When "-m" is used without a <ttl> argument, the program accepts multicast
     84  * rwhod reports from all multicast-capable interfaces.  If a <ttl> argument
     85  * is given, it accepts multicast reports from only one interface, the one
     86  * on which reports are sent (which may be controlled via the host's routing
     87  * table).  Regardless of the "-m" option, the program accepts broadcast or
     88  * unicast reports from all interfaces.  Thus, this program will hear the
     89  * reports of old, non-multicasting rwhods, but, if multicasting is used,
     90  * those old rwhods won't hear the reports generated by this program.
     91  *
     92  *                  -- Steve Deering, Stanford University, February 1989
     93  */
     94 
     95 #define	NO_MULTICAST		0	  /* multicast modes */
     96 #define	PER_INTERFACE_MULTICAST	1
     97 #define	SCOPED_MULTICAST	2
     98 
     99 #define	MAX_MULTICAST_SCOPE	32	  /* "site-wide", by convention */
    100 
    101 #define	INADDR_WHOD_GROUP	(ulong_t)0xe0000103	/* 224.0.1.3 */
    102 					/* (belongs in protocols/rwhod.h) */
    103 
    104 static int			multicast_mode  = NO_MULTICAST;
    105 static int			multicast_scope;
    106 static struct sockaddr_in	multicast_addr  = { AF_INET };
    107 
    108 
    109 /*
    110  * Alarm interval. Don't forget to change the down time check in ruptime
    111  * if this is changed.
    112  */
    113 #define	AL_INTERVAL (3 * 60)
    114 
    115 static struct	sockaddr_in sin = { AF_INET };
    116 
    117 static char	myname[MAXHOSTNAMELEN];
    118 
    119 /*
    120  * We communicate with each neighbor in
    121  * a list constructed at the time we're
    122  * started up.  Neighbors are currently
    123  * directly connected via a hardware interface.
    124  */
    125 struct	neighbor {
    126 	struct	neighbor *n_next;
    127 	char	*n_name;		/* interface name */
    128 	char	*n_addr;		/* who to send to */
    129 	int	n_addrlen;		/* size of address */
    130 	ulong_t	n_subnet;		/* AF_INET subnet */
    131 	uint_t	n_flags;		/* should forward?, interface flags */
    132 };
    133 
    134 static struct	neighbor *neighbors;
    135 static struct	whod mywd;
    136 static struct	servent *sp;
    137 static int	s;
    138 
    139 #define	WHDRSIZE	(sizeof (mywd) - sizeof (mywd.wd_we))
    140 #define	RWHODIR		"/var/spool/rwho"
    141 
    142 static void		onalrm(void);
    143 static void		getkmem(void);
    144 static boolean_t	configure(int);
    145 static int		verify(const struct whod *);
    146 
    147 int
    148 main(int argc, char *argv[])
    149 {
    150 	struct sockaddr_in from;
    151 	struct stat st;
    152 	char path[64];
    153 	struct hostent *hp;
    154 	int on = 1;
    155 	char *cp;
    156 	struct stat sb;
    157 
    158 	if (getuid()) {
    159 		(void) fprintf(stderr, "in.rwhod: not super user\n");
    160 		exit(1);
    161 	}
    162 	sp = getservbyname("who", "udp");
    163 	if (sp == NULL) {
    164 		(void) fprintf(stderr, "in.rwhod: udp/who: unknown service\n");
    165 		exit(1);
    166 	}
    167 	argv++;
    168 	argc--;
    169 	while (argc > 0 && *argv[0] == '-') {
    170 		if (strcmp(*argv, "-m") == 0) {
    171 			if (argc > 1 && isdigit(*(argv + 1)[0])) {
    172 				argv++;
    173 				argc--;
    174 				multicast_mode  = SCOPED_MULTICAST;
    175 				multicast_scope = atoi(*argv);
    176 				if (multicast_scope > MAX_MULTICAST_SCOPE) {
    177 					(void) fprintf(stderr,
    178 					    "in.rwhod: "
    179 					    "ttl must not exceed %u\n",
    180 					    MAX_MULTICAST_SCOPE);
    181 					exit(1);
    182 				}
    183 			} else {
    184 				multicast_mode = PER_INTERFACE_MULTICAST;
    185 			}
    186 		} else {
    187 			goto usage;
    188 		}
    189 		argv++;
    190 		argc--;
    191 	}
    192 	if (argc > 0)
    193 		goto usage;
    194 	if (chdir(RWHODIR) < 0) {
    195 		perror(RWHODIR);
    196 		exit(1);
    197 	}
    198 #ifndef DEBUG
    199 	if (fork())
    200 		exit(0);
    201 	/* CSTYLED */
    202 	{
    203 		(void) close(0);
    204 		(void) close(1);
    205 		(void) close(2);
    206 		(void) open("/", 0);
    207 		(void) dup2(0, 1);
    208 		(void) dup2(0, 2);
    209 		(void) setsid();
    210 	}
    211 #endif
    212 	(void) sigset(SIGHUP, (void (*)())getkmem);
    213 	openlog("in.rwhod", LOG_PID, LOG_DAEMON);
    214 	/*
    215 	 * Establish host name as returned by system.
    216 	 */
    217 	if (gethostname(myname, sizeof (myname) - 1) < 0) {
    218 		syslog(LOG_ERR, "main: gethostname: %m");
    219 		exit(1);
    220 	}
    221 	if ((cp = index(myname, '.')) != NULL)
    222 		*cp = '\0';
    223 	(void) strlcpy(mywd.wd_hostname, myname, sizeof (mywd.wd_hostname));
    224 
    225 	if (stat(UTMPX_FILE, &sb) < 0) {
    226 		syslog(LOG_ERR, "main: stat: %s: %m", UTMPX_FILE);
    227 		exit(1);
    228 	}
    229 	getkmem();
    230 	if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
    231 		syslog(LOG_ERR, "main: socket: %m");
    232 		exit(1);
    233 	}
    234 	if (setsockopt(s, SOL_SOCKET, SO_BROADCAST, &on, sizeof (on)) < 0) {
    235 		syslog(LOG_ERR, "main: setsockopt SO_BROADCAST: %m");
    236 		exit(1);
    237 	}
    238 	hp = gethostbyname(myname);
    239 	if (hp == NULL) {
    240 		syslog(LOG_ERR, "main: %s: don't know my own name\n", myname);
    241 		exit(1);
    242 	}
    243 	sin.sin_family = hp->h_addrtype;
    244 	sin.sin_port = sp->s_port;
    245 	if (bind(s, (struct sockaddr *)&sin, sizeof (sin)) < 0) {
    246 		syslog(LOG_ERR, "main: bind: %m");
    247 		exit(1);
    248 	}
    249 	if (!configure(s))
    250 		exit(1);
    251 	(void) sigset(SIGALRM, (void (*)())onalrm);
    252 	onalrm();
    253 	for (;;) {
    254 		struct whod wd;
    255 		int cc, whod;
    256 		socklen_t len = sizeof (from);
    257 
    258 		cc = recvfrom(s, &wd, sizeof (struct whod), 0,
    259 		    (struct sockaddr *)&from, &len);
    260 		if (cc <= 0) {
    261 			if (cc < 0 && errno != EINTR)
    262 				syslog(LOG_WARNING, "main: recvfrom: %m");
    263 			continue;
    264 		}
    265 		if (from.sin_port != sp->s_port) {
    266 			syslog(LOG_WARNING, "main: %d: bad from port",
    267 			    ntohs(from.sin_port));
    268 			continue;
    269 		}
    270 #ifdef notdef
    271 		if (gethostbyname(wd.wd_hostname) == 0) {
    272 			syslog(LOG_WARNING, "main: %s: unknown host",
    273 			    wd.wd_hostname);
    274 			continue;
    275 		}
    276 #endif
    277 		if (wd.wd_vers != WHODVERSION)
    278 			continue;
    279 		if (wd.wd_type != WHODTYPE_STATUS)
    280 			continue;
    281 		if (!verify(&wd)) {
    282 			syslog(LOG_WARNING, "main: malformed host name from %x",
    283 			    from.sin_addr.s_addr);
    284 			continue;
    285 		}
    286 		(void) sprintf(path, "whod.%s", wd.wd_hostname);
    287 		/*
    288 		 * Rather than truncating and growing the file each time,
    289 		 * use ftruncate if size is less than previous size.
    290 		 */
    291 		whod = open(path, O_WRONLY | O_CREAT, 0644);
    292 		if (whod < 0) {
    293 			syslog(LOG_WARNING, "main: open: %s: %m", path);
    294 			continue;
    295 		}
    296 #if defined(_LITTLE_ENDIAN)
    297 		/* CSTYLED */
    298 		{
    299 			int i, n = (cc - WHDRSIZE)/sizeof (struct whoent);
    300 			struct whoent *we;
    301 
    302 			/* undo header byte swapping before writing to file */
    303 			wd.wd_sendtime = ntohl(wd.wd_sendtime);
    304 			for (i = 0; i < 3; i++)
    305 				wd.wd_loadav[i] = ntohl(wd.wd_loadav[i]);
    306 			wd.wd_boottime = ntohl(wd.wd_boottime);
    307 			we = wd.wd_we;
    308 			for (i = 0; i < n; i++) {
    309 				we->we_idle = ntohl(we->we_idle);
    310 				we->we_utmp.out_time =
    311 				    ntohl(we->we_utmp.out_time);
    312 				we++;
    313 			}
    314 		}
    315 #endif
    316 		(void) time((time_t *)&wd.wd_recvtime);
    317 		(void) write(whod, &wd, cc);
    318 		if (fstat(whod, &st) < 0 || st.st_size > cc)
    319 			(void) ftruncate(whod, cc);
    320 		(void) close(whod);
    321 	}
    322 	/* NOTREACHED */
    323 usage:
    324 	(void) fprintf(stderr, "usage: in.rwhod [ -m [ ttl ] ]\n");
    325 	return (1);
    326 }
    327 
    328 /*
    329  * Check out host name for unprintables
    330  * and other funnies before allowing a file
    331  * to be created.  Sorry, but blanks aren't allowed.
    332  */
    333 static int
    334 verify(const struct whod *wd)
    335 {
    336 	int size = 0;
    337 	const char *name = wd->wd_hostname;
    338 
    339 	/*
    340 	 * We shouldn't assume the name is NUL terminated, so bound the
    341 	 * checks at the size of the whod structures wd_hostname field.
    342 	 */
    343 	while ((size < sizeof (wd->wd_hostname)) &&
    344 	    (*name != '\0')) {
    345 		if (*name == '/' || !isascii(*name) ||
    346 		    !(isalnum(*name) || ispunct(*name)))
    347 			return (0);
    348 		name++, size++;
    349 	}
    350 	/*
    351 	 * Fail the verification if NULL name or it wasn't NUL terminated.
    352 	 */
    353 	return ((size > 0) && (size < sizeof (wd->wd_hostname)));
    354 }
    355 
    356 static int	utmpxtime;
    357 static int	utmpxent;
    358 static int	alarmcount;
    359 struct	utmpx *utmpx;
    360 
    361 static void
    362 onalrm(void)
    363 {
    364 	int i;
    365 	struct stat stb;
    366 	int	utmpxsize = 0;
    367 	int	entries;
    368 	struct	utmpx *utp;
    369 	struct	utmpx *utmpxbegin;
    370 	struct whoent *we = mywd.wd_we, *wlast;
    371 	int cc, cnt;
    372 	double avenrun[3];
    373 
    374 	time_t now = time(0);
    375 	struct neighbor *np;
    376 
    377 	if (alarmcount % 10 == 0)
    378 		getkmem();
    379 	alarmcount++;
    380 	(void) stat(UTMPX_FILE, &stb);
    381 	entries = stb.st_size / sizeof (struct futmpx);
    382 	if ((stb.st_mtime != utmpxtime) || (entries > utmpxent)) {
    383 		utmpxtime = stb.st_mtime;
    384 		if (entries > utmpxent) {
    385 			utmpxent = entries;
    386 			utmpxsize = utmpxent * sizeof (struct utmpx);
    387 			utmpx = realloc(utmpx, utmpxsize);
    388 			if (utmpx == NULL) {
    389 				syslog(LOG_ERR, "onalrm: realloc: %m");
    390 				utmpxsize = 0;
    391 				goto done;
    392 			}
    393 		}
    394 		utmpxbegin = utmpx;
    395 		setutxent();
    396 		cnt = 0;
    397 		while (cnt++ < utmpxent && (utp = getutxent()) != NULL)
    398 			(void) memcpy(utmpxbegin++, utp, sizeof (struct utmpx));
    399 		endutxent();
    400 		wlast = &mywd.wd_we[1024 / sizeof (struct whoent) - 1];
    401 		for (i = 0; i < utmpxent; i++) {
    402 			if (utmpx[i].ut_name[0] &&
    403 			    utmpx[i].ut_type == USER_PROCESS) {
    404 				/*
    405 				 * XXX - utmpx name and line lengths should
    406 				 * be here
    407 				 */
    408 				bcopy(utmpx[i].ut_line, we->we_utmp.out_line,
    409 				    sizeof (we->we_utmp.out_line));
    410 				bcopy(utmpx[i].ut_name, we->we_utmp.out_name,
    411 				    sizeof (we->we_utmp.out_name));
    412 				we->we_utmp.out_time =
    413 				    htonl(utmpx[i].ut_xtime);
    414 				if (we >= wlast)
    415 					break;
    416 				we++;
    417 			}
    418 		}
    419 		utmpxent = we - mywd.wd_we;
    420 	}
    421 
    422 	/*
    423 	 * The test on utmpxent looks silly---after all, if no one is
    424 	 * logged on, why worry about efficiency?---but is useful on
    425 	 * (e.g.) compute servers.
    426 	 */
    427 	if (utmpxent > 0 && chdir("/dev") == -1) {
    428 		syslog(LOG_ERR, "onalrm: chdir /dev: %m");
    429 		exit(1);
    430 	}
    431 	we = mywd.wd_we;
    432 	for (i = 0; i < utmpxent; i++) {
    433 		if (stat(we->we_utmp.out_line, &stb) >= 0)
    434 			we->we_idle = htonl(now - stb.st_atime);
    435 		we++;
    436 	}
    437 	if (getloadavg(avenrun, 3) == -1) {
    438 		syslog(LOG_ERR, "onalrm: getloadavg: %m");
    439 		exit(1);
    440 	}
    441 
    442 	for (i = 0; i < 3; i++)
    443 		mywd.wd_loadav[i] = htonl((ulong_t)(avenrun[i] * 100));
    444 	cc = (char *)we - (char *)&mywd;
    445 	mywd.wd_sendtime = htonl(time(0));
    446 	mywd.wd_vers = WHODVERSION;
    447 	mywd.wd_type = WHODTYPE_STATUS;
    448 	if (multicast_mode == SCOPED_MULTICAST) {
    449 		(void) sendto(s, &mywd, cc, 0,
    450 		    (struct sockaddr *)&multicast_addr,
    451 		    sizeof (multicast_addr));
    452 	} else for (np = neighbors; np != NULL; np = np->n_next) {
    453 		if (multicast_mode == PER_INTERFACE_MULTICAST &&
    454 		    np->n_flags & IFF_MULTICAST) {
    455 			/*
    456 			 * Select the outgoing interface for the multicast.
    457 			 */
    458 			if (setsockopt(s, IPPROTO_IP, IP_MULTICAST_IF,
    459 			    &(((struct sockaddr_in *)np->n_addr)->sin_addr),
    460 			    sizeof (struct in_addr)) < 0) {
    461 				syslog(LOG_ERR,
    462 				    "onalrm: setsockopt IP_MULTICAST_IF: %m");
    463 				exit(1);
    464 			}
    465 			(void) sendto(s, &mywd, cc, 0,
    466 			    (struct sockaddr *)&multicast_addr,
    467 			    sizeof (multicast_addr));
    468 		} else {
    469 			(void) sendto(s, &mywd, cc, 0,
    470 			    (struct sockaddr *)np->n_addr, np->n_addrlen);
    471 		}
    472 	}
    473 	if (utmpxent > 0 && chdir(RWHODIR) == -1) {
    474 		syslog(LOG_ERR, "onalrm: chdir %s: %m", RWHODIR);
    475 		exit(1);
    476 	}
    477 done:
    478 	(void) alarm(AL_INTERVAL);
    479 }
    480 
    481 static void
    482 getkmem(void)
    483 {
    484 	struct utmpx *utmpx, utmpx_id;
    485 
    486 	utmpx_id.ut_type = BOOT_TIME;
    487 	if ((utmpx = getutxid(&utmpx_id)) != NULL)
    488 		mywd.wd_boottime = utmpx->ut_xtime;
    489 	endutxent();
    490 	mywd.wd_boottime = htonl(mywd.wd_boottime);
    491 }
    492 
    493 /*
    494  * Figure out device configuration and select
    495  * networks which deserve status information.
    496  */
    497 static boolean_t
    498 configure(int s)
    499 {
    500 	char *buf;
    501 	struct ifconf ifc;
    502 	struct ifreq ifreq, *ifr;
    503 	struct sockaddr_in *sin;
    504 	struct neighbor *np;
    505 	struct neighbor *np2;
    506 	int n;
    507 	int numifs;
    508 	unsigned bufsize;
    509 
    510 	if (multicast_mode == SCOPED_MULTICAST) {
    511 		struct ip_mreq mreq;
    512 		unsigned char ttl;
    513 
    514 		mreq.imr_multiaddr.s_addr = htonl(INADDR_WHOD_GROUP);
    515 		mreq.imr_interface.s_addr = htonl(INADDR_ANY);
    516 		if (setsockopt(s, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq,
    517 		    sizeof (mreq)) < 0) {
    518 			syslog(LOG_ERR,
    519 			    "configure: setsockopt IP_ADD_MEMBERSHIP: %m");
    520 			return (B_FALSE);
    521 		}
    522 		ttl = multicast_scope;
    523 		if (setsockopt(s, IPPROTO_IP, IP_MULTICAST_TTL, &ttl,
    524 		    sizeof (ttl)) < 0) {
    525 			syslog(LOG_ERR,
    526 			    "configure: setsockopt IP_MULTICAST_TTL: %m");
    527 			return (B_FALSE);
    528 		}
    529 		multicast_addr.sin_addr.s_addr = htonl(INADDR_WHOD_GROUP);
    530 		multicast_addr.sin_port = sp->s_port;
    531 		return (B_TRUE);
    532 	}
    533 
    534 	if (ioctl(s, SIOCGIFNUM, (char *)&numifs) < 0) {
    535 		syslog(LOG_ERR, "configure: ioctl SIOCGIFNUM: %m");
    536 		return (B_FALSE);
    537 	}
    538 	bufsize = numifs * sizeof (struct ifreq);
    539 	buf = malloc(bufsize);
    540 	if (buf == NULL) {
    541 		syslog(LOG_ERR, "configure: malloc: %m");
    542 		return (B_FALSE);
    543 	}
    544 	ifc.ifc_len = bufsize;
    545 	ifc.ifc_buf = buf;
    546 	if (ioctl(s, SIOCGIFCONF, (char *)&ifc) < 0) {
    547 		syslog(LOG_ERR,
    548 		    "configure: ioctl (get interface configuration): %m");
    549 		(void) free(buf);
    550 		return (B_FALSE);
    551 	}
    552 	ifr = ifc.ifc_req;
    553 	for (n = ifc.ifc_len / sizeof (struct ifreq); n > 0; n--, ifr++) {
    554 		/* Skip all logical interfaces */
    555 		if (index(ifr->ifr_name, ':') != NULL)
    556 			continue;
    557 
    558 		for (np = neighbors; np != NULL; np = np->n_next) {
    559 			if (np->n_name &&
    560 			    strcmp(ifr->ifr_name, np->n_name) == 0)
    561 				break;
    562 		}
    563 		if (np != NULL)
    564 			continue;
    565 		ifreq = *ifr;
    566 		np = (struct neighbor *)malloc(sizeof (*np));
    567 		if (np == NULL)
    568 			continue;
    569 		np->n_name = malloc(strlen(ifr->ifr_name) + 1);
    570 		if (np->n_name == NULL) {
    571 			free(np);
    572 			continue;
    573 		}
    574 		(void) strcpy(np->n_name, ifr->ifr_name);
    575 		np->n_addrlen = sizeof (ifr->ifr_addr);
    576 		np->n_addr = malloc(np->n_addrlen);
    577 		if (np->n_addr == NULL) {
    578 			free(np->n_name);
    579 			free(np);
    580 			continue;
    581 		}
    582 		bcopy(&ifr->ifr_addr, np->n_addr, np->n_addrlen);
    583 		if (ioctl(s, SIOCGIFFLAGS, (char *)&ifreq) < 0) {
    584 			syslog(LOG_ERR,
    585 			    "configure: ioctl (get interface flags): %m");
    586 			free(np->n_addr);
    587 			free(np->n_name);
    588 			free(np);
    589 			continue;
    590 		}
    591 		np->n_flags = ifreq.ifr_flags;
    592 		if (((struct sockaddr_in *)np->n_addr)->sin_family == AF_INET &&
    593 		    ioctl(s, SIOCGIFNETMASK, (char *)&ifreq) >= 0) {
    594 			sin = (struct sockaddr_in *)np->n_addr;
    595 
    596 			np->n_subnet = sin->sin_addr.s_addr &
    597 			    ((struct sockaddr_in *)&ifreq.ifr_addr)->
    598 			    sin_addr.s_addr;
    599 		}
    600 		if (multicast_mode == PER_INTERFACE_MULTICAST &&
    601 		    (np->n_flags & IFF_UP) &&
    602 		    (np->n_flags & IFF_MULTICAST) &&
    603 		    !(np->n_flags & IFF_LOOPBACK)) {
    604 			struct ip_mreq mreq;
    605 
    606 			/*
    607 			 * Skip interfaces that have matching subnets i.e.
    608 			 * (addr & netmask) are identical.
    609 			 * Such interfaces are connected to the same
    610 			 * physical wire.
    611 			 */
    612 			for (np2 = neighbors; np2 != NULL; np2 = np2->n_next) {
    613 
    614 				if (!(np->n_flags & IFF_POINTOPOINT) &&
    615 				    !(np2->n_flags & IFF_POINTOPOINT) &&
    616 				    (np->n_subnet == np2->n_subnet)) {
    617 					free(np->n_addr);
    618 					free(np->n_name);
    619 					free(np);
    620 					break;
    621 				}
    622 			}
    623 			if (np2 != NULL)
    624 				continue;
    625 
    626 			mreq.imr_multiaddr.s_addr = htonl(INADDR_WHOD_GROUP);
    627 			mreq.imr_interface.s_addr =
    628 			    ((struct sockaddr_in *)np->n_addr)->sin_addr.s_addr;
    629 			if (setsockopt(s, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq,
    630 			    sizeof (mreq)) < 0) {
    631 				syslog(LOG_ERR,
    632 				    "configure: "
    633 				    "setsockopt IP_ADD_MEMBERSHIP: %m");
    634 				free(np->n_addr);
    635 				free(np->n_name);
    636 				free(np);
    637 				continue;
    638 			}
    639 			multicast_addr.sin_addr.s_addr =
    640 			    htonl(INADDR_WHOD_GROUP);
    641 			multicast_addr.sin_port = sp->s_port;
    642 			np->n_next = neighbors;
    643 			neighbors = np;
    644 			continue;
    645 		}
    646 		if ((np->n_flags & IFF_UP) == 0 ||
    647 		    (np->n_flags & (IFF_BROADCAST|IFF_POINTOPOINT)) == 0) {
    648 			free(np->n_addr);
    649 			free(np->n_name);
    650 			free(np);
    651 			continue;
    652 		}
    653 		if (np->n_flags & IFF_POINTOPOINT) {
    654 			if (ioctl(s, SIOCGIFDSTADDR, (char *)&ifreq) < 0) {
    655 				syslog(LOG_ERR,
    656 				    "configure: ioctl (get dstaddr): %m");
    657 				free(np->n_addr);
    658 				free(np->n_name);
    659 				free(np);
    660 				continue;
    661 			}
    662 			/* we assume addresses are all the same size */
    663 			bcopy(&ifreq.ifr_dstaddr, np->n_addr, np->n_addrlen);
    664 		}
    665 		if (np->n_flags & IFF_BROADCAST) {
    666 			if (ioctl(s, SIOCGIFBRDADDR, (char *)&ifreq) < 0) {
    667 				syslog(LOG_ERR,
    668 				    "configure: ioctl (get broadaddr): %m");
    669 				free(np->n_addr);
    670 				free(np->n_name);
    671 				free(np);
    672 				continue;
    673 			}
    674 			/* we assume addresses are all the same size */
    675 			bcopy(&ifreq.ifr_broadaddr, np->n_addr, np->n_addrlen);
    676 		}
    677 		/* gag, wish we could get rid of Internet dependencies */
    678 		sin = (struct sockaddr_in *)np->n_addr;
    679 		sin->sin_port = sp->s_port;
    680 
    681 		/*
    682 		 * Avoid adding duplicate broadcast and pt-pt destinations
    683 		 * to the list.
    684 		 */
    685 		for (np2 = neighbors; np2 != NULL; np2 = np2->n_next) {
    686 			struct sockaddr_in *sin2;
    687 
    688 			sin2 = (struct sockaddr_in *)np2->n_addr;
    689 			if (sin2->sin_addr.s_addr == sin->sin_addr.s_addr) {
    690 				free(np->n_addr);
    691 				free(np->n_name);
    692 				free(np);
    693 				break;
    694 			}
    695 		}
    696 		if (np2 != NULL)
    697 			continue;
    698 
    699 		np->n_next = neighbors;
    700 		neighbors = np;
    701 	}
    702 	(void) free(buf);
    703 	return (B_TRUE);
    704 }
    705 
    706 #ifdef DEBUG
    707 static char *interval(uint_t, char *);
    708 
    709 /* ARGSUSED */
    710 static ssize_t
    711 sendto(int s, const void *buf, size_t cc, int flags, const struct sockaddr *to,
    712     socklen_t tolen)
    713 {
    714 	struct whod *w = (struct whod *)buf;
    715 	struct whoent *we;
    716 	struct sockaddr_in *sin = (struct sockaddr_in *)to;
    717 	int nsz;
    718 
    719 	(void) printf("sendto %x.%d\n", ntohl(sin->sin_addr.s_addr),
    720 	    ntohs(sin->sin_port));
    721 	(void) printf("hostname %s %s\n", w->wd_hostname,
    722 	    interval(ntohl(w->wd_sendtime) - ntohl(w->wd_boottime), "  up"));
    723 	(void) printf("load %4.2f, %4.2f, %4.2f\n",
    724 	    ntohl(w->wd_loadav[0]) / 100.0, ntohl(w->wd_loadav[1]) / 100.0,
    725 	    ntohl(w->wd_loadav[2]) / 100.0);
    726 	cc -= WHDRSIZE;
    727 	for (we = w->wd_we, cc /= sizeof (struct whoent); cc > 0; cc--, we++) {
    728 		time_t t = ntohl(we->we_utmp.out_time);
    729 
    730 		nsz = sizeof (we->we_utmp.out_name);
    731 		(void) printf("%-*.*s %s:%s %.12s",
    732 		    nsz,
    733 		    nsz,
    734 		    we->we_utmp.out_name,
    735 		    w->wd_hostname,
    736 		    we->we_utmp.out_line,
    737 		    ctime(&t)+4);
    738 		we->we_idle = ntohl(we->we_idle) / 60;
    739 		if (we->we_idle) {
    740 			if (we->we_idle >= 100*60)
    741 				we->we_idle = 100*60 - 1;
    742 			if (we->we_idle >= 60)
    743 				(void) printf(" %2d", we->we_idle / 60);
    744 			else
    745 				(void) printf("   ");
    746 			(void) printf(":%02d", we->we_idle % 60);
    747 		}
    748 		(void) printf("\n");
    749 	}
    750 	return (0);
    751 }
    752 
    753 static char *
    754 interval(uint_t time, char *updown)
    755 {
    756 	static char resbuf[32];
    757 	int days, hours, minutes;
    758 
    759 	if (time > 3*30*24*60*60) {
    760 		(void) sprintf(resbuf, "   %s ??:??", updown);
    761 		return (resbuf);
    762 	}
    763 	minutes = (time + 59) / 60;		/* round to minutes */
    764 	hours = minutes / 60;
    765 	minutes %= 60;
    766 	days = hours / 24;
    767 	hours %= 24;
    768 	if (days > 0) {
    769 		(void) sprintf(resbuf, "%s %2d+%02d:%02d",
    770 		    updown, days, hours, minutes);
    771 	} else {
    772 		(void) sprintf(resbuf, "%s    %2d:%02d",
    773 		    updown, hours, minutes);
    774 	}
    775 	return (resbuf);
    776 }
    777 #endif
    778