usr.sbin/rwhod/rwhod.c

   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. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  * @(#) Copyright (c) 1983, 1993 The Regents of the University of California.  All rights reserved.
  30  * @(#)rwhod.c  8.1 (Berkeley) 6/6/93
  31  * $FreeBSD: src/usr.sbin/rwhod/rwhod.c,v 1.13.2.2 2000/12/23 15:28:12 iedowse Exp $
  32  */
  33
  34 #include <sys/param.h>
  35 #include <sys/socket.h>
  36 #include <sys/stat.h>
  37 #include <sys/signal.h>
  38 #include <sys/ioctl.h>
  39 #include <sys/sysctl.h>
  40
  41 #include <net/if.h>
  42 #include <net/if_dl.h>
  43 #include <net/route.h>
  44 #include <netinet/in.h>
  45 #include <arpa/inet.h>
  46 #include <protocols/rwhod.h>
  47
  48 #include <ctype.h>
  49 #include <err.h>
  50 #include <errno.h>
  51 #include <fcntl.h>
  52 #include <libutil.h>
  53 #include <netdb.h>
  54 #include <paths.h>
  55 #include <poll.h>
  56 #include <stdio.h>
  57 #include <stdlib.h>
  58 #include <string.h>
  59 #include <syslog.h>
  60 #include <timeconv.h>
  61 #include <unistd.h>
  62 #include <utmpx.h>
  63 #include <pwd.h>
  64 #include <grp.h>
  65
  66 /*
  67  * This version of Berkeley's rwhod has been modified to use IP multicast
  68  * datagrams, under control of a new command-line option:
  69  *
  70  *      rwhod -m        causes rwhod to use IP multicast (instead of
  71  *                      broadcast or unicast) on all interfaces that have
  72  *                      the IFF_MULTICAST flag set in their "ifnet" structs
  73  *                      (excluding the loopback interface).  The multicast
  74  *                      reports are sent with a time-to-live of 1, to prevent
  75  *                      forwarding beyond the directly-connected subnet(s).
  76  *
  77  *      rwhod -m <ttl>  causes rwhod to send IP multicast datagrams with a
  78  *                      time-to-live of <ttl>, via a SINGLE interface rather
  79  *                      than all interfaces.  <ttl> must be between 0 and
  80  *                      MAX_MULTICAST_SCOPE, defined below.  Note that "-m 1"
  81  *                      is different than "-m", in that "-m 1" specifies
  82  *                      transmission on one interface only.
  83  *
  84  * When "-m" is used without a <ttl> argument, the program accepts multicast
  85  * rwhod reports from all multicast-capable interfaces.  If a <ttl> argument
  86  * is given, it accepts multicast reports from only one interface, the one
  87  * on which reports are sent (which may be controlled via the host's routing
  88  * table).  Regardless of the "-m" option, the program accepts broadcast or
  89  * unicast reports from all interfaces.  Thus, this program will hear the
  90  * reports of old, non-multicasting rwhods, but, if multicasting is used,
  91  * those old rwhods won't hear the reports generated by this program.
  92  *
  93  *                  -- Steve Deering, Stanford University, February 1989
  94  */
  95
  96 #define UNPRIV_USER             "daemon"
  97 #define UNPRIV_GROUP            "daemon"
  98
  99 #define WITH_ERRNO              1       /* Write to syslog with errno (%m) */
 100 #define WITHOUT_ERRNO           0       /* Write to syslog without errno */
 101
 102 #define NO_MULTICAST            0         /* multicast modes */
 103 #define PER_INTERFACE_MULTICAST 1
 104 #define SCOPED_MULTICAST        2
 105
 106 #define MAX_MULTICAST_SCOPE     32        /* "site-wide", by convention */
 107
 108 #define INADDR_WHOD_GROUP (u_long)0xe0000103      /* 224.0.1.3 */
 109                                           /* (belongs in protocols/rwhod.h) */
 110
 111 static int                      insecure_mode;
 112 static int                      quiet_mode;
 113 static int                      iff_flag = IFF_POINTOPOINT;
 114 static int                      multicast_mode  = NO_MULTICAST;
 115 static int                      multicast_scope;
 116 static struct sockaddr_in       multicast_addr;
 117
 118 static char     myname[MAXHOSTNAMELEN];
 119
 120 /*
 121  * We communicate with each neighbor in a list constructed at the time we're
 122  * started up.  Neighbors are currently directly connected via a hardware
 123  * interface.
 124  */
 125 struct  neighbor {
 126         struct  neighbor *n_next;
 127         char    *n_name;                /* interface name */
 128         struct  sockaddr *n_addr;               /* who to send to */
 129         int     n_addrlen;              /* size of address */
 130         int     n_flags;                /* should forward?, interface flags */
 131 };
 132
 133 static struct   neighbor *neighbors;
 134 static struct   whod mywd;
 135 static struct   servent *sp;
 136 static int      s;
 137 static volatile sig_atomic_t    onsighup;
 138
 139 #define WHDRSIZE        (sizeof(mywd) - sizeof(mywd.wd_we))
 140
 141 static void      run_as(uid_t *, gid_t *);
 142 static int       configure(int);
 143 static void      getboottime(void);
 144 static void      send_host_information(void);
 145 static void      hup(int);
 146 static void      quit(const char *, int) __dead2;
 147 static void      rt_xaddrs(caddr_t, caddr_t, struct rt_addrinfo *);
 148 static int       verify(char *, int);
 149 static void      handleread(int);
 150 static void      usage(void) __dead2;
 151 static void      timeadd(struct timeval *, time_t, struct timeval *);
 152
 153 #ifdef DEBUG
 154 static char     *interval(int, const char *);
 155 static ssize_t  Sendto(int, const void *, size_t, int,
 156                      const struct sockaddr *, int);
 157 #else
 158 #define Sendto sendto
 159 #endif
 160
 161 int
 162 main(int argc, char *argv[])
 163 {
 164         struct pollfd pfd[1];
 165         char *ep, *cp;
 166         int on = 1;
 167         int send_time = 180;    /* Default time, 180 seconds (3 minutes) */
 168         struct sockaddr_in m_sin;
 169         uid_t unpriv_uid;
 170         gid_t unpriv_gid;
 171         long tmp;
 172         time_t delta = 0;
 173         struct timeval next = { .tv_sec = 0 }, now;
 174
 175         if (getuid())
 176                 errx(1, "not super user");
 177
 178         run_as(&unpriv_uid, &unpriv_gid);
 179
 180         argv++; argc--;
 181         while (argc > 0 && *argv[0] == '-') {
 182                 if (strcmp(*argv, "-m") == 0) {
 183                         if (argc > 1 && *(argv + 1)[0] != '-') {
 184                                 /* Argument has been given */
 185                                 argv++, argc--;
 186                                 multicast_mode = SCOPED_MULTICAST;
 187                                 tmp = strtol(*argv, &ep, 10);
 188                                 if (*ep != '\0' || tmp < INT_MIN || tmp > INT_MAX)
 189                                         errx(1, "invalid ttl: %s", *argv);
 190                                 multicast_scope = (int)tmp;
 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                 } else if (strcmp(*argv, "-g") == 0) {
 197                         if (argc > 1 && *(argv + 1)[0] != '-') {
 198                                 argv++, argc--;
 199                                 send_time = (int)strtol(*argv, &ep, 10);
 200                                 if (send_time <= 0)
 201                                         errx(1, "time must be greater than 0");
 202
 203                                 if (ep[0] != '\0') {
 204                                         if (ep[1] != '\0')
 205                                                 errx(1, "invalid argument: %s", *argv);
 206                                         if (*ep == 'M' || *ep == 'm') {
 207                                                 /* Time in minutes. */
 208                                                 send_time *= 60;
 209                                         } else
 210                                                 errx(1, "invalid argument: %s", *argv);
 211                                 }
 212
 213                                 if (send_time > 180)
 214                                         errx(1, "cannot be greater than 180 seconds (3 minutes)");
 215                         } else
 216                                 errx(1, "missing argument");
 217                 } else if (strcmp(*argv, "-i") == 0)
 218                         insecure_mode = 1;
 219                 else if (strcmp(*argv, "-l") == 0)
 220                         quiet_mode = 1;
 221                 else if (strcmp(*argv, "-p") == 0)
 222                         iff_flag = 0;
 223                 else
 224                         usage();
 225                 argv++, argc--;
 226         }
 227         if (argc > 0)
 228                 usage();
 229 #ifndef DEBUG
 230         struct pidfh *pfh = NULL;
 231         pfh = pidfile_open(NULL, 600, NULL);
 232         daemon(1, 0);
 233         pidfile_write(pfh);
 234 #endif
 235         signal(SIGHUP, hup);
 236         openlog("rwhod", LOG_PID, LOG_DAEMON);
 237         sp = getservbyname("who", "udp");
 238         if (sp == NULL)
 239                 quit("udp/who: unknown service", WITHOUT_ERRNO);
 240
 241         if (chdir(_PATH_RWHODIR) < 0)
 242                 quit(_PATH_RWHODIR, WITH_ERRNO);
 243
 244         /*
 245          * Establish host name as returned by system.
 246          */
 247         if (gethostname(myname, sizeof(myname)) < 0)
 248                 quit("gethostname", WITH_ERRNO);
 249
 250         if ((cp = strchr(myname, '.')) != NULL)
 251                 *cp = '\0';
 252         strlcpy(mywd.wd_hostname, myname, sizeof(mywd.wd_hostname));
 253         getboottime();
 254         if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
 255                 quit("socket", WITH_ERRNO);
 256
 257         if (setsockopt(s, SOL_SOCKET, SO_BROADCAST, &on, sizeof(on)) < 0)
 258                 quit("setsockopt SO_BROADCAST", WITH_ERRNO);
 259
 260         memset(&m_sin, 0, sizeof(m_sin));
 261         m_sin.sin_len = sizeof(m_sin);
 262         m_sin.sin_family = AF_INET;
 263         m_sin.sin_port = sp->s_port;
 264         if (bind(s, (struct sockaddr *)&m_sin, sizeof(m_sin)) < 0)
 265                 quit("bind", WITH_ERRNO);
 266
 267         setgid(unpriv_gid);
 268         setgroups(1, &unpriv_gid);      /* XXX BOGUS groups[0] = egid */
 269         setuid(unpriv_uid);
 270         if (!configure(s))
 271                 exit(1);
 272
 273         if (!quiet_mode) {
 274                 send_host_information();
 275                 delta = send_time;
 276                 gettimeofday(&now, NULL);
 277                 timeadd(&now, delta, &next);
 278         }
 279
 280         pfd[0].fd = s;
 281         pfd[0].events = POLLIN;
 282
 283         for (;;) {
 284                 int n;
 285
 286                 n = poll(pfd, 1, 1000);
 287
 288                 if (onsighup) {
 289                         onsighup = 0;
 290                         getboottime();
 291                 }
 292
 293                 if (n == 1)
 294                         handleread(s);
 295                 if (!quiet_mode) {
 296                         gettimeofday(&now, NULL);
 297                         if (now.tv_sec > next.tv_sec) {
 298                                 send_host_information();
 299                                 timeadd(&now, delta, &next);
 300                         }
 301                 }
 302         }
 303 }
 304
 305 static void
 306 timeadd(struct timeval *now, time_t delta, struct timeval *next)
 307 {
 308         (next)->tv_sec = (now)->tv_sec + delta;
 309 }
 310
 311 static void
 312 handleread(int sock)
 313 {
 314         struct sockaddr_in from;
 315         struct stat st;
 316         char path[64];
 317         struct whod wd;
 318         int cc, whod;
 319         socklen_t len = sizeof(from);
 320
 321         cc = recvfrom(sock, (char *)&wd, sizeof(struct whod), 0,
 322                 (struct sockaddr *)&from, &len);
 323         if (cc == 0)
 324                 return;
 325
 326         if (cc < 0 && errno != EINTR) {
 327                 syslog(LOG_WARNING, "recv: %m");
 328                 return;
 329         }
 330
 331         if (from.sin_port != sp->s_port && !insecure_mode) {
 332                 syslog(LOG_WARNING, "%d: bad source port from %s",
 333                     ntohs(from.sin_port), inet_ntoa(from.sin_addr));
 334                 return;
 335         }
 336         if (cc < (int)WHDRSIZE) {
 337                 syslog(LOG_WARNING, "short packet from %s",
 338                     inet_ntoa(from.sin_addr));
 339                 return;
 340         }
 341         if (wd.wd_vers != WHODVERSION)
 342                 return;
 343         if (wd.wd_type != WHODTYPE_STATUS)
 344                 return;
 345         if (!verify(wd.wd_hostname, sizeof wd.wd_hostname)) {
 346                 syslog(LOG_WARNING, "malformed host name from %s",
 347                     inet_ntoa(from.sin_addr));
 348                 return;
 349         }
 350         snprintf(path, sizeof path, "whod.%s", wd.wd_hostname);
 351         /*
 352          * Rather than truncating and growing the file each time,
 353          * use ftruncate if size is less than previous size.
 354          */
 355         whod = open(path, O_WRONLY | O_CREAT, 0644);
 356         if (whod < 0) {
 357                 syslog(LOG_WARNING, "%s: %m", path);
 358                 return;
 359         }
 360 #if _BYTE_ORDER != _BIG_ENDIAN
 361         {
 362                 int i, n = (cc - WHDRSIZE)/sizeof(struct whoent);
 363                 struct whoent *we;
 364
 365                 /* undo header byte swapping before writing to file */
 366                 wd.wd_sendtime = ntohl(wd.wd_sendtime);
 367                 for (i = 0; i < 3; i++)
 368                         wd.wd_loadav[i] = ntohl(wd.wd_loadav[i]);
 369                 wd.wd_boottime = ntohl(wd.wd_boottime);
 370                 we = wd.wd_we;
 371                 for (i = 0; i < n; i++) {
 372                         we->we_idle = ntohl(we->we_idle);
 373                         we->we_utmp.out_time =
 374                             ntohl(we->we_utmp.out_time);
 375                         we++;
 376                 }
 377         }
 378 #endif
 379         wd.wd_recvtime = time(NULL);
 380         write(whod, (char *)&wd, cc);
 381         if (fstat(whod, &st) < 0 || st.st_size > cc)
 382                 ftruncate(whod, cc);
 383         close(whod);
 384 }
 385
 386 static void
 387 usage(void)
 388 {
 389         fprintf(stderr, "usage: rwhod [-i] [-p] [-l] [-m [ttl]]\n");
 390         exit(1);
 391 }
 392
 393 static void
 394 hup(int signo __unused)
 395 {
 396         onsighup = 1;
 397 }
 398
 399 static void
 400 run_as(uid_t *uid, gid_t *gid)
 401 {
 402         struct passwd *pw;
 403         struct group *gr;
 404
 405         pw = getpwnam(UNPRIV_USER);
 406         if (!pw)
 407                 quit("getpwnam(daemon)", WITH_ERRNO);
 408
 409         *uid = pw->pw_uid;
 410
 411         gr = getgrnam(UNPRIV_GROUP);
 412         if (!gr)
 413                 quit("getgrnam(daemon)", WITH_ERRNO);
 414
 415         *gid = gr->gr_gid;
 416 }
 417
 418 /*
 419  * Check out host name for unprintables
 420  * and other funnies before allowing a file
 421  * to be created.  Sorry, but blanks aren't allowed.
 422  */
 423 static int
 424 verify(char *name, int maxlen)
 425 {
 426         int size = 0;
 427
 428         while (*name && size < maxlen - 1) {
 429                 if (!isascii(*name) || !(isalnum(*name) || ispunct(*name)))
 430                         return (0);
 431                 name++, size++;
 432         }
 433         *name = '\0';
 434         return (size > 0);
 435 }
 436
 437 static void
 438 send_host_information(void)
 439 {
 440         struct neighbor *np;
 441         struct whoent *we = mywd.wd_we, *wend;
 442         struct stat stb;
 443         struct utmpx *ut;
 444         static int alarmcount = 0;
 445         double avenrun[3];
 446         time_t now;
 447         int i, cc;
 448
 449         now = time(NULL);
 450         if (alarmcount % 10 == 0)
 451                 getboottime();
 452         alarmcount++;
 453         wend = &mywd.wd_we[1024 / sizeof(struct whoent)];
 454         setutxent();
 455         while ((ut = getutxent()) != NULL && we < wend) {
 456                 if (ut->ut_type != USER_PROCESS)
 457                         continue;
 458                 strncpy(we->we_utmp.out_line, ut->ut_line,
 459                    sizeof(we->we_utmp.out_line));
 460                 strncpy(we->we_utmp.out_name, ut->ut_user,
 461                    sizeof(we->we_utmp.out_name));
 462                 we->we_utmp.out_time =
 463                     htonl(_time_to_time32(ut->ut_tv.tv_sec));
 464                 we++;
 465         }
 466         endutxent();
 467
 468         if (chdir(_PATH_DEV)) {
 469                 syslog(LOG_ERR, "chdir(%s): %m", _PATH_DEV);
 470                 exit(1);
 471         }
 472
 473         wend = we;
 474         for (we = mywd.wd_we; we < wend; we++) {
 475                 if (stat(we->we_utmp.out_line, &stb) >= 0)
 476                         we->we_idle = htonl(now - stb.st_atime);
 477         }
 478         getloadavg(avenrun, NELEM(avenrun));
 479         for (i = 0; i < 3; i++)
 480                 mywd.wd_loadav[i] = htonl((u_long)(avenrun[i] * 100));
 481         cc = (char *)wend - (char *)&mywd;
 482         mywd.wd_sendtime = htonl(time(0));
 483         mywd.wd_vers = WHODVERSION;
 484         mywd.wd_type = WHODTYPE_STATUS;
 485         if (multicast_mode == SCOPED_MULTICAST) {
 486                 Sendto(s, (char *)&mywd, cc, 0,
 487                                 (struct sockaddr *)&multicast_addr,
 488                                 sizeof(multicast_addr));
 489         }
 490         else for (np = neighbors; np != NULL; np = np->n_next) {
 491                 if (multicast_mode == PER_INTERFACE_MULTICAST &&
 492                     np->n_flags & IFF_MULTICAST) {
 493                         /*
 494                          * Select the outgoing interface for the multicast.
 495                          */
 496                         if (setsockopt(s, IPPROTO_IP, IP_MULTICAST_IF,
 497                             &(((struct sockaddr_in *)np->n_addr)->sin_addr),
 498                             sizeof(struct in_addr)) < 0) {
 499                                 quit("setsockopt IP_MULTICAST_IF", WITH_ERRNO);
 500                         }
 501                         Sendto(s, (char *)&mywd, cc, 0,
 502                                 (struct sockaddr *)&multicast_addr,
 503                                 sizeof(multicast_addr));
 504                 } else Sendto(s, (char *)&mywd, cc, 0,
 505                                 np->n_addr, np->n_addrlen);
 506         }
 507         if (chdir(_PATH_RWHODIR)) {
 508                 syslog(LOG_ERR, "chdir(%s): %m", _PATH_RWHODIR);
 509                 exit(1);
 510         }
 511 }
 512
 513 static void
 514 getboottime(void)
 515 {
 516         struct timespec uts;
 517
 518         clock_gettime(CLOCK_UPTIME, &uts);
 519         mywd.wd_boottime = htonl(time(NULL) - uts.tv_sec);
 520 }
 521
 522 /*
 523  * If wrterrno == WITH_ERRNO, we will print
 524  * errno. If not, we leave errno out.
 525  */
 526 static void
 527 quit(const char *msg, int wrterrno)
 528 {
 529         if (wrterrno)
 530                 syslog(LOG_ERR, "%s: %m", msg);
 531         else
 532                 syslog(LOG_ERR, "%s", msg);
 533         exit(1);
 534 }
 535
 536 static void
 537 rt_xaddrs(caddr_t cp, caddr_t cplim, struct rt_addrinfo *rtinfo)
 538 {
 539         struct sockaddr *sa;
 540         int i;
 541
 542         memset(rtinfo->rti_info, 0, sizeof(rtinfo->rti_info));
 543         for (i = 0; (i < RTAX_MAX) && (cp < cplim); i++) {
 544                 if ((rtinfo->rti_addrs & (1 << i)) == 0)
 545                         continue;
 546                 rtinfo->rti_info[i] = sa = (struct sockaddr *)cp;
 547                 RT_ADVANCE(cp, sa);
 548         }
 549 }
 550
 551 /*
 552  * Figure out device configuration and select
 553  * networks which deserve status information.
 554  */
 555 static int
 556 configure(int c_sock)
 557 {
 558         struct neighbor *np;
 559         struct if_msghdr *ifm;
 560         struct ifa_msghdr *ifam;
 561         struct sockaddr_dl *sdl;
 562         size_t needed;
 563         int mib[6], flags = 0, len;
 564         char *buf, *lim, *next;
 565         struct rt_addrinfo info;
 566
 567         if (multicast_mode != NO_MULTICAST) {
 568                 multicast_addr.sin_len = sizeof(multicast_addr);
 569                 multicast_addr.sin_family = AF_INET;
 570                 multicast_addr.sin_addr.s_addr = htonl(INADDR_WHOD_GROUP);
 571                 multicast_addr.sin_port = sp->s_port;
 572         }
 573
 574         if (multicast_mode == SCOPED_MULTICAST) {
 575                 struct ip_mreq mreq;
 576                 unsigned char ttl;
 577
 578                 mreq.imr_multiaddr.s_addr = htonl(INADDR_WHOD_GROUP);
 579                 mreq.imr_interface.s_addr = htonl(INADDR_ANY);
 580                 if (setsockopt(c_sock, IPPROTO_IP, IP_ADD_MEMBERSHIP,
 581                                         &mreq, sizeof(mreq)) < 0) {
 582                         syslog(LOG_ERR,
 583                                 "setsockopt IP_ADD_MEMBERSHIP: %m");
 584                         return(0);
 585                 }
 586                 ttl = multicast_scope;
 587                 if (setsockopt(c_sock, IPPROTO_IP, IP_MULTICAST_TTL,
 588                                         &ttl, sizeof(ttl)) < 0) {
 589                         syslog(LOG_ERR,
 590                                 "setsockopt IP_MULTICAST_TTL: %m");
 591                         return(0);
 592                 }
 593                 return(1);
 594         }
 595
 596         mib[0] = CTL_NET;
 597         mib[1] = PF_ROUTE;
 598         mib[2] = 0;
 599         mib[3] = AF_INET;
 600         mib[4] = NET_RT_IFLIST;
 601         mib[5] = 0;
 602         if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0)
 603                 quit("route-sysctl-estimate", WITH_ERRNO);
 604         if ((buf = malloc(needed)) == NULL)
 605                 quit("malloc", WITH_ERRNO);
 606         if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0)
 607                 quit("actual retrieval of interface table", WITH_ERRNO);
 608         lim = buf + needed;
 609
 610         sdl = NULL;             /* XXX just to keep gcc -Wall happy */
 611         for (next = buf; next < lim; next += ifm->ifm_msglen) {
 612                 ifm = (struct if_msghdr *)next;
 613                 if (ifm->ifm_type == RTM_IFINFO) {
 614                         sdl = (struct sockaddr_dl *)(ifm + 1);
 615                         flags = ifm->ifm_flags;
 616                         continue;
 617                 }
 618                 if ((flags & IFF_UP) == 0 ||
 619                     (flags & (((multicast_mode == PER_INTERFACE_MULTICAST) ?
 620                                 IFF_MULTICAST : 0) |
 621                                 IFF_BROADCAST|iff_flag)) == 0)
 622                         continue;
 623                 if (ifm->ifm_type != RTM_NEWADDR)
 624                         quit("out of sync parsing NET_RT_IFLIST", WITHOUT_ERRNO);
 625                 ifam = (struct ifa_msghdr *)ifm;
 626                 info.rti_addrs = ifam->ifam_addrs;
 627                 rt_xaddrs((char *)(ifam + 1), ifam->ifam_msglen + (char *)ifam,
 628                         &info);
 629                 /* gag, wish we could get rid of Internet dependencies */
 630 #define dstaddr info.rti_info[RTAX_BRD]
 631 #define ifaddr info.rti_info[RTAX_IFA]
 632 #define IPADDR_SA(x) ((struct sockaddr_in *)(x))->sin_addr.s_addr
 633 #define PORT_SA(x) ((struct sockaddr_in *)(x))->sin_port
 634                 if (dstaddr == 0 || dstaddr->sa_family != AF_INET)
 635                         continue;
 636                 PORT_SA(dstaddr) = sp->s_port;
 637                 for (np = neighbors; np != NULL; np = np->n_next)
 638                         if (memcmp(sdl->sdl_data, np->n_name,
 639                                    sdl->sdl_nlen) == 0 &&
 640                             IPADDR_SA(np->n_addr) == IPADDR_SA(dstaddr))
 641                                 break;
 642                 if (np != NULL)
 643                         continue;
 644                 len = sizeof(*np) + dstaddr->sa_len + sdl->sdl_nlen + 1;
 645                 np = (struct neighbor *)malloc(len);
 646                 if (np == NULL)
 647                         quit("malloc of neighbor structure", WITH_ERRNO);
 648                 memset(np, 0, len);
 649                 np->n_flags = flags;
 650                 np->n_addr = (struct sockaddr *)(np + 1);
 651                 np->n_addrlen = dstaddr->sa_len;
 652                 np->n_name = np->n_addrlen + (char *)np->n_addr;
 653                 memcpy((char *)np->n_addr, (char *)dstaddr, np->n_addrlen);
 654                 memcpy(np->n_name, sdl->sdl_data, sdl->sdl_nlen);
 655                 if (multicast_mode == PER_INTERFACE_MULTICAST &&
 656                     (flags & IFF_MULTICAST) &&
 657                    !(flags & IFF_LOOPBACK)) {
 658                         struct ip_mreq mreq;
 659
 660                         memcpy((char *)np->n_addr, (char *)ifaddr,
 661                                 np->n_addrlen);
 662                         mreq.imr_multiaddr.s_addr = htonl(INADDR_WHOD_GROUP);
 663                         mreq.imr_interface.s_addr =
 664                           ((struct sockaddr_in *)np->n_addr)->sin_addr.s_addr;
 665                         if (setsockopt(s, IPPROTO_IP, IP_ADD_MEMBERSHIP,
 666                                                 &mreq, sizeof(mreq)) < 0) {
 667                                 syslog(LOG_ERR,
 668                                     "setsockopt IP_ADD_MEMBERSHIP: %m");
 669 #if 0
 670                                 /* Fall back to broadcast on this if. */
 671                                 np->n_flags &= ~IFF_MULTICAST;
 672 #else
 673                                 free((char *)np);
 674                                 continue;
 675 #endif
 676                         }
 677                 }
 678                 np->n_next = neighbors;
 679                 neighbors = np;
 680         }
 681         free(buf);
 682         return (1);
 683 }
 684
 685 #ifdef DEBUG
 686 static ssize_t
 687 Sendto(int s_debug, const void *buf, size_t cc, int flags,
 688        const struct sockaddr *to, int tolen)
 689 {
 690         const struct whod *w = (const struct whod *)buf;
 691         const struct whoent *we;
 692         const struct sockaddr_in *sock_in = (const struct sockaddr_in *)to;
 693         ssize_t ret;
 694         int idle_time;
 695
 696         ret = sendto(s_debug, buf, cc, flags, to, tolen);
 697
 698         printf("sendto %s:%d\n", inet_ntoa(sock_in->sin_addr),
 699                                  ntohs(sock_in->sin_port));
 700         printf("hostname %s %s\n", w->wd_hostname,
 701            interval(ntohl(w->wd_sendtime) - ntohl(w->wd_boottime), "  up"));
 702         printf("load %4.2f, %4.2f, %4.2f\n",
 703             ntohl(w->wd_loadav[0]) / 100.0, ntohl(w->wd_loadav[1]) / 100.0,
 704             ntohl(w->wd_loadav[2]) / 100.0);
 705         cc -= WHDRSIZE;
 706         for (we = w->wd_we, cc /= sizeof(struct whoent); cc > 0; cc--, we++) {
 707                 time_t t = ntohl(we->we_utmp.out_time);
 708                 idle_time = we->we_idle;
 709                 printf("%-8.8s %s:%s %.12s",
 710                         we->we_utmp.out_name,
 711                         w->wd_hostname, we->we_utmp.out_line,
 712                         ctime(&t)+4);
 713                 idle_time = ntohl(we->we_idle) / 60;
 714                 if (idle_time) {
 715                         if (idle_time >= 100*60)
 716                                 idle_time = 100*60 - 1;
 717                         if (idle_time >= 60)
 718                                 printf(" %2d", idle_time / 60);
 719                         else
 720                                 printf("   ");
 721                         printf(":%02d", idle_time % 60);
 722                 }
 723                 printf("\n");
 724         }
 725         return(ret);
 726 }
 727
 728 static char *
 729 interval(int inter_time, const char *updown)
 730 {
 731         static char resbuf[32];
 732         int days, hours, minutes;
 733
 734         if (inter_time < 0 || inter_time > 3*30*24*60*60) {
 735                 snprintf(resbuf, sizeof(resbuf), "   %s ??:??", updown);
 736                 return (resbuf);
 737         }
 738         minutes = (inter_time + 59) / 60;               /* round to minutes */
 739         hours = minutes / 60; minutes %= 60;
 740         days = hours / 24; hours %= 24;
 741         if (days)
 742                 snprintf(resbuf, sizeof(resbuf), "%s %2d+%02d:%02d",
 743                     updown, days, hours, minutes);
 744         else
 745                 snprintf(resbuf, sizeof(resbuf), "%s    %2d:%02d",
 746                     updown, hours, minutes);
 747         return (resbuf);
 748 }
 749 #endif