usr.sbin/timed/timed/master.c

   1 /*-
   2  * Copyright (c) 1985, 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  * 4. 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
  30 #ifndef lint
  31 #if 0
  32 static char sccsid[] = "@(#)master.c    8.1 (Berkeley) 6/6/93";
  33 #endif
  34 static const char rcsid[] =
  35   "$FreeBSD$";
  36 #endif /* not lint */
  37
  38 #include "globals.h"
  39 #include <sys/file.h>
  40 #include <sys/types.h>
  41 #include <sys/times.h>
  42 #include <setjmp.h>
  43 #include <utmpx.h>
  44 #include "pathnames.h"
  45
  46 extern int measure_delta;
  47 extern jmp_buf jmpenv;
  48 extern int Mflag;
  49 extern int justquit;
  50
  51 static int dictate;
  52 static int slvcount;                    /* slaves listening to our clock */
  53
  54 static void mchgdate(struct tsp *);
  55
  56 /*
  57  * The main function of `master' is to periodically compute the differences
  58  * (deltas) between its clock and the clocks of the slaves, to compute the
  59  * network average delta, and to send to the slaves the differences between
  60  * their individual deltas and the network delta.
  61  * While waiting, it receives messages from the slaves (i.e. requests for
  62  * master's name, remote requests to set the network time, ...), and
  63  * takes the appropriate action.
  64  */
  65 int
  66 master(void)
  67 {
  68         struct hosttbl *htp;
  69         long pollingtime;
  70 #define POLLRATE 4
  71         int polls;
  72         struct timeval wait, ntime;
  73         time_t tsp_time_sec;
  74         struct tsp *msg, *answer, to;
  75         char newdate[32];
  76         struct sockaddr_in taddr;
  77         char tname[MAXHOSTNAMELEN];
  78         struct netinfo *ntp;
  79         int i;
  80
  81         syslog(LOG_NOTICE, "This machine is master");
  82         if (trace)
  83                 fprintf(fd, "This machine is master\n");
  84         for (ntp = nettab; ntp != NULL; ntp = ntp->next) {
  85                 if (ntp->status == MASTER)
  86                         masterup(ntp);
  87         }
  88         (void)gettimeofday(&ntime, NULL);
  89         pollingtime = ntime.tv_sec+3;
  90         if (justquit)
  91                 polls = 0;
  92         else
  93                 polls = POLLRATE-1;
  94
  95 /* Process all outstanding messages before spending the long time necessary
  96  *      to update all timers.
  97  */
  98 loop:
  99         (void)gettimeofday(&ntime, NULL);
 100         wait.tv_sec = pollingtime - ntime.tv_sec;
 101         if (wait.tv_sec < 0)
 102                 wait.tv_sec = 0;
 103         wait.tv_usec = 0;
 104         msg = readmsg(TSP_ANY, ANYADDR, &wait, 0);
 105         if (!msg) {
 106                 (void)gettimeofday(&ntime, NULL);
 107                 if (ntime.tv_sec >= pollingtime) {
 108                         pollingtime = ntime.tv_sec + SAMPLEINTVL;
 109                         get_goodgroup(0);
 110
 111 /* If a bogus master told us to quit, we can have decided to ignore a
 112  * network.  Therefore, periodically try to take over everything.
 113  */
 114                         polls = (polls + 1) % POLLRATE;
 115                         if (0 == polls && nignorednets > 0) {
 116                                 trace_msg("Looking for nets to re-master\n");
 117                                 for (ntp = nettab; ntp; ntp = ntp->next) {
 118                                         if (ntp->status == IGNORE
 119                                             || ntp->status == NOMASTER) {
 120                                                 lookformaster(ntp);
 121                                                 if (ntp->status == MASTER) {
 122                                                         masterup(ntp);
 123                                                         polls = POLLRATE-1;
 124                                                 }
 125                                         }
 126                                         if (ntp->status == MASTER
 127                                             && --ntp->quit_count < 0)
 128                                                 ntp->quit_count = 0;
 129                                 }
 130                                 if (polls != 0)
 131                                         setstatus();
 132                         }
 133
 134                         synch(0L);
 135
 136                         for (ntp = nettab; ntp != NULL; ntp = ntp->next) {
 137                                 to.tsp_type = TSP_LOOP;
 138                                 to.tsp_vers = TSPVERSION;
 139                                 to.tsp_seq = sequence++;
 140                                 to.tsp_hopcnt = MAX_HOPCNT;
 141                                 (void)strcpy(to.tsp_name, hostname);
 142                                 bytenetorder(&to);
 143                                 if (sendto(sock, (char *)&to,
 144                                            sizeof(struct tsp), 0,
 145                                            (struct sockaddr*)&ntp->dest_addr,
 146                                            sizeof(ntp->dest_addr)) < 0) {
 147                                    trace_sendto_err(ntp->dest_addr.sin_addr);
 148                                 }
 149                         }
 150                 }
 151
 152
 153         } else {
 154                 switch (msg->tsp_type) {
 155
 156                 case TSP_MASTERREQ:
 157                         break;
 158
 159                 case TSP_SLAVEUP:
 160                         newslave(msg);
 161                         break;
 162
 163                 case TSP_SETDATE:
 164                         /*
 165                          * XXX check to see it is from ourself
 166                          */
 167                         tsp_time_sec = msg->tsp_time.tv_sec;
 168                         (void)strlcpy(newdate, ctime(&tsp_time_sec),
 169                             sizeof(newdate));
 170                         if (!good_host_name(msg->tsp_name)) {
 171                                 syslog(LOG_NOTICE,
 172                                        "attempted date change by %s to %s",
 173                                        msg->tsp_name, newdate);
 174                                 spreadtime();
 175                                 break;
 176                         }
 177
 178                         mchgdate(msg);
 179                         (void)gettimeofday(&ntime, NULL);
 180                         pollingtime = ntime.tv_sec + SAMPLEINTVL;
 181                         break;
 182
 183                 case TSP_SETDATEREQ:
 184                         if (!fromnet || fromnet->status != MASTER)
 185                                 break;
 186                         tsp_time_sec = msg->tsp_time.tv_sec;
 187                         (void)strlcpy(newdate, ctime(&tsp_time_sec),
 188                             sizeof(newdate));
 189                         htp = findhost(msg->tsp_name);
 190                         if (htp == NULL) {
 191                                 syslog(LOG_ERR,
 192                                        "attempted SET DATEREQ by uncontrolled %s to %s",
 193                                        msg->tsp_name, newdate);
 194                                 break;
 195                         }
 196                         if (htp->seq == msg->tsp_seq)
 197                                 break;
 198                         htp->seq = msg->tsp_seq;
 199                         if (!htp->good) {
 200                                 syslog(LOG_NOTICE,
 201                                 "attempted SET DATEREQ by untrusted %s to %s",
 202                                        msg->tsp_name, newdate);
 203                                 spreadtime();
 204                                 break;
 205                         }
 206
 207                         mchgdate(msg);
 208                         (void)gettimeofday(&ntime, NULL);
 209                         pollingtime = ntime.tv_sec + SAMPLEINTVL;
 210                         break;
 211
 212                 case TSP_MSITE:
 213                         xmit(TSP_ACK, msg->tsp_seq, &from);
 214                         break;
 215
 216                 case TSP_MSITEREQ:
 217                         break;
 218
 219                 case TSP_TRACEON:
 220                         traceon();
 221                         break;
 222
 223                 case TSP_TRACEOFF:
 224                         traceoff("Tracing ended at %s\n");
 225                         break;
 226
 227                 case TSP_ELECTION:
 228                         if (!fromnet)
 229                                 break;
 230                         if (fromnet->status == MASTER) {
 231                                 pollingtime = 0;
 232                                 (void)addmach(msg->tsp_name, &from,fromnet);
 233                         }
 234                         taddr = from;
 235                         (void)strcpy(tname, msg->tsp_name);
 236                         to.tsp_type = TSP_QUIT;
 237                         (void)strcpy(to.tsp_name, hostname);
 238                         answer = acksend(&to, &taddr, tname,
 239                                          TSP_ACK, 0, 1);
 240                         if (answer == NULL) {
 241                                 syslog(LOG_ERR, "election error by %s",
 242                                        tname);
 243                         }
 244                         break;
 245
 246                 case TSP_CONFLICT:
 247                         /*
 248                          * After a network partition, there can be
 249                          * more than one master: the first slave to
 250                          * come up will notify here the situation.
 251                          */
 252                         if (!fromnet || fromnet->status != MASTER)
 253                                 break;
 254                         (void)strcpy(to.tsp_name, hostname);
 255
 256                         /* The other master often gets into the same state,
 257                          * with boring results if we stay at it forever.
 258                          */
 259                         ntp = fromnet;  /* (acksend() can leave fromnet=0 */
 260                         for (i = 0; i < 3; i++) {
 261                                 to.tsp_type = TSP_RESOLVE;
 262                                 (void)strcpy(to.tsp_name, hostname);
 263                                 answer = acksend(&to, &ntp->dest_addr,
 264                                                  ANYADDR, TSP_MASTERACK,
 265                                                  ntp, 0);
 266                                 if (!answer)
 267                                         break;
 268                                 htp = addmach(answer->tsp_name,&from,ntp);
 269                                 to.tsp_type = TSP_QUIT;
 270                                 msg = acksend(&to, &htp->addr, htp->name,
 271                                               TSP_ACK, 0, htp->noanswer);
 272                                 if (msg == NULL) {
 273                                         syslog(LOG_ERR,
 274                                     "no response from %s to CONFLICT-QUIT",
 275                                                htp->name);
 276                                 }
 277                         }
 278                         masterup(ntp);
 279                         pollingtime = 0;
 280                         break;
 281
 282                 case TSP_RESOLVE:
 283                         if (!fromnet || fromnet->status != MASTER)
 284                                 break;
 285                         /*
 286                          * do not want to call synch() while waiting
 287                          * to be killed!
 288                          */
 289                         (void)gettimeofday(&ntime, NULL);
 290                         pollingtime = ntime.tv_sec + SAMPLEINTVL;
 291                         break;
 292
 293                 case TSP_QUIT:
 294                         doquit(msg);            /* become a slave */
 295                         break;
 296
 297                 case TSP_LOOP:
 298                         if (!fromnet || fromnet->status != MASTER
 299                             || !strcmp(msg->tsp_name, hostname))
 300                                 break;
 301                         /*
 302                          * We should not have received this from a net
 303                          * we are master on.  There must be two masters.
 304                          */
 305                         htp = addmach(msg->tsp_name, &from,fromnet);
 306                         to.tsp_type = TSP_QUIT;
 307                         (void)strcpy(to.tsp_name, hostname);
 308                         answer = acksend(&to, &htp->addr, htp->name,
 309                                          TSP_ACK, 0, 1);
 310                         if (!answer) {
 311                                 syslog(LOG_WARNING,
 312                                 "loop breakage: no reply from %s=%s to QUIT",
 313                                     htp->name, inet_ntoa(htp->addr.sin_addr));
 314                                 (void)remmach(htp);
 315                         }
 316
 317                 case TSP_TEST:
 318                         if (trace) {
 319                                 fprintf(fd,
 320                 "\tnets = %d, masters = %d, slaves = %d, ignored = %d\n",
 321                 nnets, nmasternets, nslavenets, nignorednets);
 322                                 setstatus();
 323                         }
 324                         pollingtime = 0;
 325                         polls = POLLRATE-1;
 326                         break;
 327
 328                 default:
 329                         if (trace) {
 330                                 fprintf(fd, "garbage message: ");
 331                                 print(msg, &from);
 332                         }
 333                         break;
 334                 }
 335         }
 336         goto loop;
 337 }
 338
 339
 340 /*
 341  * change the system date on the master
 342  */
 343 static void
 344 mchgdate(struct tsp *msg)
 345 {
 346         char tname[MAXHOSTNAMELEN];
 347         char olddate[32];
 348         struct timeval otime, ntime, tmptv;
 349         struct utmpx utx;
 350
 351         (void)strcpy(tname, msg->tsp_name);
 352
 353         xmit(TSP_DATEACK, msg->tsp_seq, &from);
 354
 355         (void)strlcpy(olddate, date(), sizeof(olddate));
 356
 357         /* adjust time for residence on the queue */
 358         (void)gettimeofday(&otime, NULL);
 359         adj_msg_time(msg,&otime);
 360
 361         tmptv.tv_sec = msg->tsp_time.tv_sec;
 362         tmptv.tv_usec = msg->tsp_time.tv_usec;
 363         timevalsub(&ntime, &tmptv, &otime);
 364         if (ntime.tv_sec < MAXADJ && ntime.tv_sec > -MAXADJ) {
 365                 /*
 366                  * do not change the clock if we can adjust it
 367                  */
 368                 dictate = 3;
 369                 synch(tvtomsround(ntime));
 370         } else {
 371                 utx.ut_type = OLD_TIME;
 372                 (void)gettimeofday(&utx.ut_tv, NULL);
 373                 pututxline(&utx);
 374                 (void)settimeofday(&tmptv, 0);
 375                 utx.ut_type = NEW_TIME;
 376                 (void)gettimeofday(&utx.ut_tv, NULL);
 377                 pututxline(&utx);
 378                 spreadtime();
 379         }
 380
 381         syslog(LOG_NOTICE, "date changed by %s from %s",
 382                tname, olddate);
 383 }
 384
 385
 386 /*
 387  * synchronize all of the slaves
 388  */
 389 void
 390 synch(long mydelta)
 391 {
 392         struct hosttbl *htp;
 393         int measure_status;
 394         struct timeval check, stop, wait;
 395
 396         if (slvcount > 0) {
 397                 if (trace)
 398                         fprintf(fd, "measurements starting at %s\n", date());
 399                 (void)gettimeofday(&check, NULL);
 400                 for (htp = self.l_fwd; htp != &self; htp = htp->l_fwd) {
 401                         if (htp->noanswer != 0) {
 402                                 measure_status = measure(500, 100,
 403                                                          htp->name,
 404                                                          &htp->addr,0);
 405                         } else {
 406                                 measure_status = measure(3000, 100,
 407                                                          htp->name,
 408                                                          &htp->addr,0);
 409                         }
 410                         if (measure_status != GOOD) {
 411                                 /* The slave did not respond.  We have
 412                                  * just wasted lots of time on it.
 413                                  */
 414                                 htp->delta = HOSTDOWN;
 415                                 if (++htp->noanswer >= LOSTHOST) {
 416                                         if (trace) {
 417                                                 fprintf(fd,
 418                                         "purging %s for not answering ICMP\n",
 419                                                         htp->name);
 420                                                 (void)fflush(fd);
 421                                         }
 422                                         htp = remmach(htp);
 423                                 }
 424                         } else {
 425                                 htp->delta = measure_delta;
 426                         }
 427                         (void)gettimeofday(&stop, NULL);
 428                         timevalsub(&stop, &stop, &check);
 429                         if (stop.tv_sec >= 1) {
 430                                 if (trace)
 431                                         (void)fflush(fd);
 432                                 /*
 433                                  * ack messages periodically
 434                                  */
 435                                 wait.tv_sec = 0;
 436                                 wait.tv_usec = 0;
 437                                 if (0 != readmsg(TSP_TRACEON,ANYADDR,
 438                                                  &wait,0))
 439                                         traceon();
 440                                 (void)gettimeofday(&check, NULL);
 441                         }
 442                 }
 443                 if (trace)
 444                         fprintf(fd, "measurements finished at %s\n", date());
 445         }
 446         if (!(status & SLAVE)) {
 447                 if (!dictate) {
 448                         mydelta = networkdelta();
 449                 } else {
 450                         dictate--;
 451                 }
 452         }
 453         if (trace && (mydelta != 0 || (status & SLAVE)))
 454                 fprintf(fd,"local correction of %ld ms.\n", mydelta);
 455         correct(mydelta);
 456 }
 457
 458 /*
 459  * sends the time to each slave after the master
 460  * has received the command to set the network time
 461  */
 462 void
 463 spreadtime(void)
 464 {
 465         struct hosttbl *htp;
 466         struct tsp to;
 467         struct tsp *answer;
 468         struct timeval tmptv;
 469
 470 /* Do not listen to the consensus after forcing the time.  This is because
 471  *      the consensus takes a while to reach the time we are dictating.
 472  */
 473         dictate = 2;
 474         for (htp = self.l_fwd; htp != &self; htp = htp->l_fwd) {
 475                 to.tsp_type = TSP_SETTIME;
 476                 (void)strcpy(to.tsp_name, hostname);
 477                 (void)gettimeofday(&tmptv, NULL);
 478                 to.tsp_time.tv_sec = tmptv.tv_sec;
 479                 to.tsp_time.tv_usec = tmptv.tv_usec;
 480                 answer = acksend(&to, &htp->addr, htp->name,
 481                                  TSP_ACK, 0, htp->noanswer);
 482                 if (answer == NULL) {
 483                         /* We client does not respond, then we have
 484                          * just wasted lots of time on it.
 485                          */
 486                         syslog(LOG_WARNING,
 487                                "no reply to SETTIME from %s", htp->name);
 488                         if (++htp->noanswer >= LOSTHOST) {
 489                                 if (trace) {
 490                                         fprintf(fd,
 491                                              "purging %s for not answering",
 492                                                 htp->name);
 493                                         (void)fflush(fd);
 494                                 }
 495                                 htp = remmach(htp);
 496                         }
 497                 }
 498         }
 499 }
 500
 501 void
 502 prthp(clock_t delta)
 503 {
 504         static time_t next_time;
 505         time_t this_time;
 506         struct tms tm;
 507         struct hosttbl *htp;
 508         int length, l;
 509         int i;
 510
 511         if (!fd)                        /* quit if tracing already off */
 512                 return;
 513
 514         this_time = times(&tm);
 515         if ((time_t)(this_time + delta) < next_time)
 516                 return;
 517         next_time = this_time + CLK_TCK;
 518
 519         fprintf(fd, "host table: %d entries at %s\n", slvcount, date());
 520         htp = self.l_fwd;
 521         length = 1;
 522         for (i = 1; i <= slvcount; i++, htp = htp->l_fwd) {
 523                 l = strlen(htp->name) + 1;
 524                 if (length+l >= 80) {
 525                         fprintf(fd, "\n");
 526                         length = 0;
 527                 }
 528                 length += l;
 529                 fprintf(fd, " %s", htp->name);
 530         }
 531         fprintf(fd, "\n");
 532 }
 533
 534
 535 static struct hosttbl *newhost_hash;
 536 static struct hosttbl *lasthfree = &hosttbl[0];
 537
 538
 539 struct hosttbl *                        /* answer or 0 */
 540 findhost(char *name)
 541 {
 542         int i, j;
 543         struct hosttbl *htp;
 544         char *p;
 545
 546         j= 0;
 547         for (p = name, i = 0; i < 8 && *p != '\0'; i++, p++)
 548                 j = (j << 2) ^ *p;
 549         newhost_hash = &hosttbl[j % NHOSTS];
 550
 551         htp = newhost_hash;
 552         if (htp->name[0] == '\0')
 553                 return(0);
 554         do {
 555                 if (!strcmp(name, htp->name))
 556                         return(htp);
 557                 htp = htp->h_fwd;
 558         } while (htp != newhost_hash);
 559         return(0);
 560 }
 561
 562 /*
 563  * add a host to the list of controlled machines if not already there
 564  */
 565 struct hosttbl *
 566 addmach(char *name, struct sockaddr_in *addr, struct netinfo *ntp)
 567 {
 568         struct hosttbl *ret, *p, *b, *f;
 569
 570         ret = findhost(name);
 571         if (ret == NULL) {
 572                 if (slvcount >= NHOSTS) {
 573                         if (trace) {
 574                                 fprintf(fd, "no more slots in host table\n");
 575                                 prthp(CLK_TCK);
 576                         }
 577                         syslog(LOG_ERR, "no more slots in host table");
 578                         Mflag = 0;
 579                         longjmp(jmpenv, 2); /* give up and be a slave */
 580                 }
 581
 582                 /* if our home hash slot is occupied, find a free entry
 583                  * in the hash table
 584                  */
 585                 if (newhost_hash->name[0] != '\0') {
 586                         do {
 587                                 ret = lasthfree;
 588                                 if (++lasthfree > &hosttbl[NHOSTS])
 589                                         lasthfree = &hosttbl[1];
 590                         } while (ret->name[0] != '\0');
 591
 592                         if (!newhost_hash->head) {
 593                                 /* Move an interloper using our home.  Use
 594                                  * scratch pointers in case the new head is
 595                                  * pointing to itself.
 596                                  */
 597                                 f = newhost_hash->h_fwd;
 598                                 b = newhost_hash->h_bak;
 599                                 f->h_bak = ret;
 600                                 b->h_fwd = ret;
 601                                 f = newhost_hash->l_fwd;
 602                                 b = newhost_hash->l_bak;
 603                                 f->l_bak = ret;
 604                                 b->l_fwd = ret;
 605                                 bcopy(newhost_hash,ret,sizeof(*ret));
 606                                 ret = newhost_hash;
 607                                 ret->head = 1;
 608                                 ret->h_fwd = ret;
 609                                 ret->h_bak = ret;
 610                         } else {
 611                                 /* link to an existing chain in our home
 612                                  */
 613                                 ret->head = 0;
 614                                 p = newhost_hash->h_bak;
 615                                 ret->h_fwd = newhost_hash;
 616                                 ret->h_bak = p;
 617                                 p->h_fwd = ret;
 618                                 newhost_hash->h_bak = ret;
 619                         }
 620                 } else {
 621                         ret = newhost_hash;
 622                         ret->head = 1;
 623                         ret->h_fwd = ret;
 624                         ret->h_bak = ret;
 625                 }
 626                 ret->addr = *addr;
 627                 ret->ntp = ntp;
 628                 (void)strlcpy(ret->name, name, sizeof(ret->name));
 629                 ret->good = good_host_name(name);
 630                 ret->l_fwd = &self;
 631                 ret->l_bak = self.l_bak;
 632                 self.l_bak->l_fwd = ret;
 633                 self.l_bak = ret;
 634                 slvcount++;
 635
 636                 ret->noanswer = 0;
 637                 ret->need_set = 1;
 638
 639         } else {
 640                 ret->noanswer = (ret->noanswer != 0);
 641         }
 642
 643         /* need to clear sequence number anyhow */
 644         ret->seq = 0;
 645         return(ret);
 646 }
 647
 648 /*
 649  * remove the machine with the given index in the host table.
 650  */
 651 struct hosttbl *
 652 remmach(struct hosttbl *htp)
 653 {
 654         struct hosttbl *lprv, *hnxt, *f, *b;
 655
 656         if (trace)
 657                 fprintf(fd, "remove %s\n", htp->name);
 658
 659         /* get out of the lists */
 660         htp->l_fwd->l_bak = lprv = htp->l_bak;
 661         htp->l_bak->l_fwd = htp->l_fwd;
 662         htp->h_fwd->h_bak = htp->h_bak;
 663         htp->h_bak->h_fwd = hnxt = htp->h_fwd;
 664
 665         /* If we are in the home slot, pull up the chain */
 666         if (htp->head && hnxt != htp) {
 667                 if (lprv == hnxt)
 668                         lprv = htp;
 669
 670                 /* Use scratch pointers in case the new head is pointing to
 671                  * itself.
 672                  */
 673                 f = hnxt->h_fwd;
 674                 b = hnxt->h_bak;
 675                 f->h_bak = htp;
 676                 b->h_fwd = htp;
 677                 f = hnxt->l_fwd;
 678                 b = hnxt->l_bak;
 679                 f->l_bak = htp;
 680                 b->l_fwd = htp;
 681                 hnxt->head = 1;
 682                 bcopy(hnxt, htp, sizeof(*htp));
 683                 lasthfree = hnxt;
 684         } else {
 685                 lasthfree = htp;
 686         }
 687
 688         lasthfree->name[0] = '\0';
 689         lasthfree->h_fwd = NULL;
 690         lasthfree->l_fwd = NULL;
 691         slvcount--;
 692
 693         return lprv;
 694 }
 695
 696
 697 /*
 698  * Remove all the machines from the host table that exist on the given
 699  * network.  This is called when a master transitions to a slave on a
 700  * given network.
 701  */
 702 void
 703 rmnetmachs(struct netinfo *ntp)
 704 {
 705         struct hosttbl *htp;
 706
 707         if (trace)
 708                 prthp(CLK_TCK);
 709         for (htp = self.l_fwd; htp != &self; htp = htp->l_fwd) {
 710                 if (ntp == htp->ntp)
 711                         htp = remmach(htp);
 712         }
 713         if (trace)
 714                 prthp(CLK_TCK);
 715 }
 716
 717 void
 718 masterup(struct netinfo *net)
 719 {
 720         xmit(TSP_MASTERUP, 0, &net->dest_addr);
 721
 722         /*
 723          * Do not tell new slaves our time for a while.  This ensures
 724          * we do not tell them to start using our time, before we have
 725          * found a good master.
 726          */
 727         (void)gettimeofday(&net->slvwait, NULL);
 728 }
 729
 730 void
 731 newslave(struct tsp *msg)
 732 {
 733         struct hosttbl *htp;
 734         struct tsp *answer, to;
 735         struct timeval now, tmptv;
 736
 737         if (!fromnet || fromnet->status != MASTER)
 738                 return;
 739
 740         htp = addmach(msg->tsp_name, &from,fromnet);
 741         htp->seq = msg->tsp_seq;
 742         if (trace)
 743                 prthp(0);
 744
 745         /*
 746          * If we are stable, send our time to the slave.
 747          * Do not go crazy if the date has been changed.
 748          */
 749         (void)gettimeofday(&now, NULL);
 750         if (now.tv_sec >= fromnet->slvwait.tv_sec+3
 751             || now.tv_sec < fromnet->slvwait.tv_sec) {
 752                 to.tsp_type = TSP_SETTIME;
 753                 (void)strcpy(to.tsp_name, hostname);
 754                 (void)gettimeofday(&tmptv, NULL);
 755                 to.tsp_time.tv_sec = tmptv.tv_sec;
 756                 to.tsp_time.tv_usec = tmptv.tv_usec;
 757                 answer = acksend(&to, &htp->addr,
 758                                  htp->name, TSP_ACK,
 759                                  0, htp->noanswer);
 760                 if (answer) {
 761                         htp->need_set = 0;
 762                 } else {
 763                         syslog(LOG_WARNING,
 764                                "no reply to initial SETTIME from %s",
 765                                htp->name);
 766                         htp->noanswer = LOSTHOST;
 767                 }
 768         }
 769 }
 770
 771
 772 /*
 773  * react to a TSP_QUIT:
 774  */
 775 void
 776 doquit(struct tsp *msg)
 777 {
 778         if (fromnet->status == MASTER) {
 779                 if (!good_host_name(msg->tsp_name)) {
 780                         if (fromnet->quit_count <= 0) {
 781                                 syslog(LOG_NOTICE,"untrusted %s told us QUIT",
 782                                        msg->tsp_name);
 783                                 suppress(&from, msg->tsp_name, fromnet);
 784                                 fromnet->quit_count = 1;
 785                                 return;
 786                         }
 787                         syslog(LOG_NOTICE, "untrusted %s told us QUIT twice",
 788                                msg->tsp_name);
 789                         fromnet->quit_count = 2;
 790                         fromnet->status = NOMASTER;
 791                 } else {
 792                         fromnet->status = SLAVE;
 793                 }
 794                 rmnetmachs(fromnet);
 795                 longjmp(jmpenv, 2);             /* give up and be a slave */
 796
 797         } else {
 798                 if (!good_host_name(msg->tsp_name)) {
 799                         syslog(LOG_NOTICE, "untrusted %s told us QUIT",
 800                                msg->tsp_name);
 801                         fromnet->quit_count = 2;
 802                 }
 803         }
 804 }
 805
 806 void
 807 traceon(void)
 808 {
 809         if (!fd) {
 810                 fd = fopen(_PATH_TIMEDLOG, "w");
 811                 if (!fd) {
 812                         trace = 0;
 813                         return;
 814                 }
 815                 fprintf(fd,"Tracing started at %s\n", date());
 816         }
 817         trace = 1;
 818         get_goodgroup(1);
 819         setstatus();
 820         prthp(CLK_TCK);
 821 }
 822
 823
 824 void
 825 traceoff(char *msg)
 826 {
 827         get_goodgroup(1);
 828         setstatus();
 829         prthp(CLK_TCK);
 830         if (trace) {
 831                 fprintf(fd, msg, date());
 832                 (void)fclose(fd);
 833                 fd = NULL;
 834         }
 835 #ifdef GPROF
 836         moncontrol(0);
 837         _mcleanup();
 838         moncontrol(1);
 839 #endif
 840         trace = OFF;
 841 }