usr.sbin/timed/timed/readmsg.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  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  * @(#)readmsg.c        8.1 (Berkeley) 6/6/93
  34  * $FreeBSD: src/usr.sbin/timed/timed/readmsg.c,v 1.5.2.3 2001/08/31 08:02:05 kris Exp $
  35  * $DragonFly: src/usr.sbin/timed/timed/readmsg.c,v 1.6 2004/09/05 02:20:15 dillon Exp $
  36  */
  37
  38 #include "globals.h"
  39
  40 extern char *tsptype[];
  41
  42 /*
  43  * LOOKAT checks if the message is of the requested type and comes from
  44  * the right machine, returning 1 in case of affirmative answer
  45  */
  46 #define LOOKAT(msg, mtype, mfrom, netp, froms) \
  47         (((mtype) == TSP_ANY || (mtype) == (msg).tsp_type) &&           \
  48          ((mfrom) == 0 || !strcmp((mfrom), (msg).tsp_name)) &&          \
  49          ((netp) == 0 ||                                                \
  50           ((netp)->mask & (froms).sin_addr.s_addr) == (netp)->net.s_addr))
  51
  52 struct timeval rtime, rwait, rtout;
  53 struct tsp msgin;
  54 static struct tsplist {
  55         struct tsp info;
  56         struct timeval when;
  57         struct sockaddr_in addr;
  58         struct tsplist *p;
  59 } msgslist;
  60 struct sockaddr_in from;
  61 struct netinfo *fromnet;
  62 struct timeval from_when;
  63
  64 /*
  65  * `readmsg' returns message `type' sent by `machfrom' if it finds it
  66  * either in the receive queue, or in a linked list of previously received
  67  * messages that it maintains.
  68  * Otherwise it waits to see if the appropriate message arrives within
  69  * `intvl' seconds. If not, it returns NULL.
  70  */
  71
  72 struct tsp *
  73 readmsg(int type, char *machfrom, struct timeval *intvl,
  74         struct netinfo *netfrom)
  75 {
  76         int length;
  77         fd_set ready;
  78         static struct tsplist *head = &msgslist;
  79         static struct tsplist *tail = &msgslist;
  80         static int msgcnt = 0;
  81         struct tsplist *prev;
  82         struct netinfo *ntp;
  83         struct tsplist *ptr;
  84         ssize_t n;
  85
  86         if (trace) {
  87                 fprintf(fd, "readmsg: looking for %s from %s, %s\n",
  88                         tsptype[type], machfrom == NULL ? "ANY" : machfrom,
  89                         netfrom == NULL ? "ANYNET" : inet_ntoa(netfrom->net));
  90                 if (head->p != 0) {
  91                         length = 1;
  92                         for (ptr = head->p; ptr != 0; ptr = ptr->p) {
  93                                 /* do not repeat the hundreds of messages */
  94                                 if (++length > 3) {
  95                                         if (ptr == tail) {
  96                                                 fprintf(fd,"\t ...%d skipped\n",
  97                                                         length);
  98                                         } else {
  99                                                 continue;
 100                                         }
 101                                 }
 102                                 fprintf(fd, length > 1 ? "\t" : "queue:\t");
 103                                 print(&ptr->info, &ptr->addr);
 104                         }
 105                 }
 106         }
 107
 108         ptr = head->p;
 109         prev = head;
 110
 111         /*
 112          * Look for the requested message scanning through the
 113          * linked list. If found, return it and free the space
 114          */
 115
 116         while (ptr != NULL) {
 117                 if (LOOKAT(ptr->info, type, machfrom, netfrom, ptr->addr)) {
 118 again:
 119                         msgin = ptr->info;
 120                         from = ptr->addr;
 121                         from_when = ptr->when;
 122                         prev->p = ptr->p;
 123                         if (ptr == tail)
 124                                 tail = prev;
 125                         free((char *)ptr);
 126                         fromnet = NULL;
 127                         if (netfrom == NULL)
 128                             for (ntp = nettab; ntp != NULL; ntp = ntp->next) {
 129                                     if ((ntp->mask & from.sin_addr.s_addr) ==
 130                                         ntp->net.s_addr) {
 131                                             fromnet = ntp;
 132                                             break;
 133                                     }
 134                             }
 135                         else
 136                             fromnet = netfrom;
 137                         if (trace) {
 138                                 fprintf(fd, "readmsg: found ");
 139                                 print(&msgin, &from);
 140                         }
 141
 142 /* The protocol can get far behind.  When it does, it gets
 143  *      hopelessly confused.  So delete duplicate messages.
 144  */
 145                         for (ptr = prev; (ptr = ptr->p) != NULL; prev = ptr) {
 146                                 if (ptr->addr.sin_addr.s_addr
 147                                         == from.sin_addr.s_addr
 148                                     && ptr->info.tsp_type == msgin.tsp_type) {
 149                                         if (trace)
 150                                                 fprintf(fd, "\tdup ");
 151                                         goto again;
 152                                 }
 153                         }
 154                         msgcnt--;
 155                         return(&msgin);
 156                 } else {
 157                         prev = ptr;
 158                         ptr = ptr->p;
 159                 }
 160         }
 161
 162         /*
 163          * If the message was not in the linked list, it may still be
 164          * coming from the network. Set the timer and wait
 165          * on a select to read the next incoming message: if it is the
 166          * right one, return it, otherwise insert it in the linked list.
 167          */
 168
 169         gettimeofday(&rtout, 0);
 170         timevaladd(&rtout, intvl);
 171         FD_ZERO(&ready);
 172         for (;;) {
 173                 gettimeofday(&rtime, 0);
 174                 timevalsub(&rwait, &rtout, &rtime);
 175                 if (rwait.tv_sec < 0)
 176                         rwait.tv_sec = rwait.tv_usec = 0;
 177                 else if (rwait.tv_sec == 0
 178                          && rwait.tv_usec < 1000000/CLK_TCK)
 179                         rwait.tv_usec = 1000000/CLK_TCK;
 180
 181                 if (trace) {
 182                         fprintf(fd, "readmsg: wait %ld.%6ld at %s\n",
 183                                 rwait.tv_sec, rwait.tv_usec, date());
 184                         /* Notice a full disk, as we flush trace info.
 185                          * It is better to flush periodically than at
 186                          * every line because the tracing consists of bursts
 187                          * of many lines.  Without care, tracing slows
 188                          * down the code enough to break the protocol.
 189                          */
 190                         if (rwait.tv_sec != 0
 191                             && EOF == fflush(fd))
 192                                 traceoff("Tracing ended for cause at %s\n");
 193                 }
 194
 195                 FD_SET(sock, &ready);
 196                 if (!select(sock+1, &ready, NULL, NULL, &rwait)) {
 197                         if (rwait.tv_sec == 0 && rwait.tv_usec == 0)
 198                                 return(0);
 199                         continue;
 200                 }
 201                 length = sizeof(from);
 202                 if ((n = recvfrom(sock, (char *)&msgin, sizeof(struct tsp), 0,
 203                              (struct sockaddr*)&from, &length)) < 0) {
 204                         syslog(LOG_ERR, "recvfrom: %m");
 205                         exit(1);
 206                 }
 207                 /*
 208                  * The 4.3BSD protocol spec had a 32-byte tsp_name field, and
 209                  * this is still OS-dependent.  Demand that the packet is at
 210                  * least long enough to hold a 4.3BSD packet.
 211                  */
 212                 if (n < (ssize_t)(sizeof(struct tsp) - MAXHOSTNAMELEN + 32)) {
 213                         syslog(LOG_NOTICE,
 214                             "short packet (%zd/%zu bytes) from %s",
 215                               n, sizeof(struct tsp) - MAXHOSTNAMELEN + 32,
 216                               inet_ntoa(from.sin_addr));
 217                         continue;
 218                 }
 219                 gettimeofday(&from_when, NULL);
 220                 bytehostorder(&msgin);
 221
 222                 if (msgin.tsp_vers > TSPVERSION) {
 223                         if (trace) {
 224                             fprintf(fd,"readmsg: version mismatch\n");
 225                             /* should do a dump of the packet */
 226                         }
 227                         continue;
 228                 }
 229
 230                 if (memchr(msgin.tsp_name,
 231                     '\0', sizeof msgin.tsp_name) == NULL) {
 232                         syslog(LOG_NOTICE, "hostname field not NUL terminated "
 233                             "in packet from %s", inet_ntoa(from.sin_addr));
 234                         continue;
 235                 }
 236
 237                 fromnet = NULL;
 238                 for (ntp = nettab; ntp != NULL; ntp = ntp->next)
 239                         if ((ntp->mask & from.sin_addr.s_addr) ==
 240                             ntp->net.s_addr) {
 241                                 fromnet = ntp;
 242                                 break;
 243                         }
 244
 245                 /*
 246                  * drop packets from nets we are ignoring permanently
 247                  */
 248                 if (fromnet == NULL) {
 249                         /*
 250                          * The following messages may originate on
 251                          * this host with an ignored network address
 252                          */
 253                         if (msgin.tsp_type != TSP_TRACEON &&
 254                             msgin.tsp_type != TSP_SETDATE &&
 255                             msgin.tsp_type != TSP_MSITE &&
 256                             msgin.tsp_type != TSP_TEST &&
 257                             msgin.tsp_type != TSP_TRACEOFF) {
 258                                 if (trace) {
 259                                     fprintf(fd,"readmsg: discard null net ");
 260                                     print(&msgin, &from);
 261                                 }
 262                                 continue;
 263                         }
 264                 }
 265
 266                 /*
 267                  * Throw away messages coming from this machine,
 268                  * unless they are of some particular type.
 269                  * This gets rid of broadcast messages and reduces
 270                  * master processing time.
 271                  */
 272                 if (!strcmp(msgin.tsp_name, hostname)
 273                     && msgin.tsp_type != TSP_SETDATE
 274                     && msgin.tsp_type != TSP_TEST
 275                     && msgin.tsp_type != TSP_MSITE
 276                     && msgin.tsp_type != TSP_TRACEON
 277                     && msgin.tsp_type != TSP_TRACEOFF
 278                     && msgin.tsp_type != TSP_LOOP) {
 279                         if (trace) {
 280                                 fprintf(fd, "readmsg: discard own ");
 281                                 print(&msgin, &from);
 282                         }
 283                         continue;
 284                 }
 285
 286                 /*
 287                  * Send acknowledgements here; this is faster and
 288                  * avoids deadlocks that would occur if acks were
 289                  * sent from a higher level routine.  Different
 290                  * acknowledgements are necessary, depending on
 291                  * status.
 292                  */
 293                 if (fromnet == NULL)    /* do not de-reference 0 */
 294                         ignoreack();
 295                 else if (fromnet->status == MASTER)
 296                         masterack();
 297                 else if (fromnet->status == SLAVE)
 298                         slaveack();
 299                 else
 300                         ignoreack();
 301
 302                 if (LOOKAT(msgin, type, machfrom, netfrom, from)) {
 303                         if (trace) {
 304                                 fprintf(fd, "readmsg: ");
 305                                 print(&msgin, &from);
 306                         }
 307                         return(&msgin);
 308                 } else if (++msgcnt > NHOSTS*3) {
 309
 310 /* The protocol gets hopelessly confused if it gets too far
 311 *       behind.  However, it seems able to recover from all cases of lost
 312 *       packets.  Therefore, if we are swamped, throw everything away.
 313 */
 314                         if (trace)
 315                                 fprintf(fd,
 316                                         "readmsg: discarding %d msgs\n",
 317                                         msgcnt);
 318                         msgcnt = 0;
 319                         while ((ptr=head->p) != NULL) {
 320                                 head->p = ptr->p;
 321                                 free((char *)ptr);
 322                         }
 323                         tail = head;
 324                 } else {
 325                         tail->p = (struct tsplist *)
 326                                     malloc(sizeof(struct tsplist));
 327                         tail = tail->p;
 328                         tail->p = NULL;
 329                         tail->info = msgin;
 330                         tail->addr = from;
 331                         /* timestamp msgs so SETTIMEs are correct */
 332                         tail->when = from_when;
 333                 }
 334         }
 335 }
 336
 337 /*
 338  * Send the necessary acknowledgements:
 339  * only the type ACK is to be sent by a slave
 340  */
 341 void
 342 slaveack(void)
 343 {
 344
 345         switch(msgin.tsp_type) {
 346
 347         case TSP_ADJTIME:
 348         case TSP_SETTIME:
 349         case TSP_ACCEPT:
 350         case TSP_REFUSE:
 351         case TSP_TRACEON:
 352         case TSP_TRACEOFF:
 353         case TSP_QUIT:
 354                 if (trace) {
 355                         fprintf(fd, "Slaveack: ");
 356                         print(&msgin, &from);
 357                 }
 358                 xmit(TSP_ACK,msgin.tsp_seq, &from);
 359                 break;
 360
 361         default:
 362                 if (trace) {
 363                         fprintf(fd, "Slaveack: no ack: ");
 364                         print(&msgin, &from);
 365                 }
 366                 break;
 367         }
 368 }
 369
 370 /*
 371  * Certain packets may arrive from this machine on ignored networks.
 372  * These packets should be acknowledged.
 373  */
 374 void
 375 ignoreack(void)
 376 {
 377
 378         switch(msgin.tsp_type) {
 379
 380         case TSP_TRACEON:
 381         case TSP_TRACEOFF:
 382         case TSP_QUIT:
 383                 if (trace) {
 384                         fprintf(fd, "Ignoreack: ");
 385                         print(&msgin, &from);
 386                 }
 387                 xmit(TSP_ACK,msgin.tsp_seq, &from);
 388                 break;
 389
 390         default:
 391                 if (trace) {
 392                         fprintf(fd, "Ignoreack: no ack: ");
 393                         print(&msgin, &from);
 394                 }
 395                 break;
 396         }
 397 }
 398
 399 /*
 400  * `masterack' sends the necessary acknowledgments
 401  * to the messages received by a master
 402  */
 403 void
 404 masterack(void)
 405 {
 406         struct tsp resp;
 407
 408         resp = msgin;
 409         resp.tsp_vers = TSPVERSION;
 410         strlcpy(resp.tsp_name, hostname, sizeof(resp.tsp_name));
 411
 412         switch(msgin.tsp_type) {
 413
 414         case TSP_QUIT:
 415         case TSP_TRACEON:
 416         case TSP_TRACEOFF:
 417         case TSP_MSITEREQ:
 418                 if (trace) {
 419                         fprintf(fd, "Masterack: ");
 420                         print(&msgin, &from);
 421                 }
 422                 xmit(TSP_ACK,msgin.tsp_seq, &from);
 423                 break;
 424
 425         case TSP_RESOLVE:
 426         case TSP_MASTERREQ:
 427                 if (trace) {
 428                         fprintf(fd, "Masterack: ");
 429                         print(&msgin, &from);
 430                 }
 431                 xmit(TSP_MASTERACK,msgin.tsp_seq, &from);
 432                 break;
 433
 434         default:
 435                 if (trace) {
 436                         fprintf(fd,"Masterack: no ack: ");
 437                         print(&msgin, &from);
 438                 }
 439                 break;
 440         }
 441 }
 442
 443 /*
 444  * Print a TSP message
 445  */
 446 void
 447 print(struct tsp *msg, struct sockaddr_in *addr)
 448 {
 449         char tm[26];
 450         time_t tsp_time_sec;
 451
 452         if (msg->tsp_type >= TSPTYPENUMBER) {
 453                 fprintf(fd, "bad type (%u) on packet from %s\n",
 454                   msg->tsp_type, inet_ntoa(addr->sin_addr));
 455                 return;
 456         }
 457
 458         switch (msg->tsp_type) {
 459
 460         case TSP_LOOP:
 461                 fprintf(fd, "%s %d %-6u #%d %-15s %s\n",
 462                         tsptype[msg->tsp_type],
 463                         msg->tsp_vers,
 464                         msg->tsp_seq,
 465                         msg->tsp_hopcnt,
 466                         inet_ntoa(addr->sin_addr),
 467                         msg->tsp_name);
 468                 break;
 469
 470         case TSP_SETTIME:
 471         case TSP_SETDATE:
 472         case TSP_SETDATEREQ:
 473                 tsp_time_sec = msg->tsp_time.tv_sec;
 474                 strlcpy(tm, ctime(&tsp_time_sec)+3+1, sizeof(tm));
 475                 fprintf(fd, "%s %d %-6u %s %-15s %s\n",
 476                         tsptype[msg->tsp_type],
 477                         msg->tsp_vers,
 478                         msg->tsp_seq,
 479                         tm,
 480                         inet_ntoa(addr->sin_addr),
 481                         msg->tsp_name);
 482                 break;
 483
 484         case TSP_ADJTIME:
 485                 fprintf(fd, "%s %d %-6u (%ld,%ld) %-15s %s\n",
 486                         tsptype[msg->tsp_type],
 487                         msg->tsp_vers,
 488                         msg->tsp_seq,
 489                         msg->tsp_time.tv_sec,
 490                         msg->tsp_time.tv_usec,
 491                         inet_ntoa(addr->sin_addr),
 492                         msg->tsp_name);
 493                 break;
 494
 495         default:
 496                 fprintf(fd, "%s %d %-6u %-15s %s\n",
 497                         tsptype[msg->tsp_type],
 498                         msg->tsp_vers,
 499                         msg->tsp_seq,
 500                         inet_ntoa(addr->sin_addr),
 501                         msg->tsp_name);
 502                 break;
 503         }
 504 }