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