1 /* $NetBSD: readmsg.c,v 1.22 2008/02/16 07:30:15 matt Exp $ */ 2 3 /*- 4 * Copyright (c) 1985, 1993 The Regents of the University of California. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 #ifndef lint 34 #if 0 35 static char sccsid[] = "@(#)readmsg.c 8.1 (Berkeley) 6/6/93"; 36 #else 37 __RCSID("$NetBSD: readmsg.c,v 1.22 2008/02/16 07:30:15 matt Exp $"); 38 #endif 39 #endif /* not lint */ 40 41 #include "globals.h" 42 43 extern const char * const tsptype[]; 44 45 /* 46 * LOOKAT checks if the message is of the requested type and comes from 47 * the right machine, returning 1 in case of affirmative answer 48 */ 49 #define LOOKAT(msg, mtype, mfrom, netp, froms) \ 50 (((mtype) == TSP_ANY || (mtype) == (msg).tsp_type) && \ 51 ((mfrom) == 0 || !strcmp((mfrom), (msg).tsp_name)) && \ 52 ((netp) == 0 || \ 53 ((netp)->mask & (froms).sin_addr.s_addr) == (netp)->net.s_addr)) 54 55 struct timeval rtime, rwait, rtout; 56 struct tsp msgin; 57 static struct tsplist { 58 struct tsp info; 59 struct timeval when; 60 struct sockaddr_in addr; 61 struct tsplist *p; 62 } msgslist; 63 struct sockaddr_in from; 64 struct netinfo *fromnet; 65 struct timeval from_when; 66 67 /* 68 * `readmsg' returns message `type' sent by `machfrom' if it finds it 69 * either in the receive queue, or in a linked list of previously received 70 * messages that it maintains. 71 * Otherwise it waits to see if the appropriate message arrives within 72 * `intvl' seconds. If not, it returns NULL. 73 */ 74 75 struct tsp * 76 readmsg(int type, char *machfrom, struct timeval *intvl, 77 struct netinfo *netfrom) 78 { 79 socklen_t length; 80 struct pollfd set[1]; 81 static struct tsplist *head = &msgslist; 82 static struct tsplist *tail = &msgslist; 83 static int msgcnt = 0; 84 struct tsplist *prev; 85 struct netinfo *ntp; 86 struct tsplist *ptr; 87 ssize_t n; 88 89 if (trace) { 90 fprintf(fd, "readmsg: looking for %s from %s, %s\n", 91 tsptype[type], machfrom == NULL ? "ANY" : machfrom, 92 netfrom == NULL ? "ANYNET" : inet_ntoa(netfrom->net)); 93 if (head->p != 0) { 94 length = 1; 95 for (ptr = head->p; ptr != 0; ptr = ptr->p) { 96 /* do not repeat the hundreds of messages */ 97 if (++length > 3) { 98 if (ptr == tail) { 99 fprintf(fd,"\t ...%d skipped\n", 100 length); 101 } else { 102 continue; 103 } 104 } 105 fprintf(fd, length > 1 ? "\t" : "queue:\t"); 106 print(&ptr->info, &ptr->addr); 107 } 108 } 109 } 110 111 ptr = head->p; 112 prev = head; 113 114 /* 115 * Look for the requested message scanning through the 116 * linked list. If found, return it and free the space 117 */ 118 119 while (ptr != NULL) { 120 if (LOOKAT(ptr->info, type, machfrom, netfrom, ptr->addr)) { 121 again: 122 msgin = ptr->info; 123 from = ptr->addr; 124 from_when = ptr->when; 125 prev->p = ptr->p; 126 if (ptr == tail) 127 tail = prev; 128 free(ptr); 129 fromnet = NULL; 130 if (netfrom == NULL) 131 for (ntp = nettab; ntp != NULL; ntp = ntp->next) { 132 if ((ntp->mask & from.sin_addr.s_addr) == 133 ntp->net.s_addr) { 134 fromnet = ntp; 135 break; 136 } 137 } 138 else 139 fromnet = netfrom; 140 if (trace) { 141 fprintf(fd, "readmsg: found "); 142 print(&msgin, &from); 143 } 144 145 /* The protocol can get far behind. When it does, it gets 146 * hopelessly confused. So delete duplicate messages. 147 */ 148 for (ptr = prev; (ptr = ptr->p) != NULL; prev = ptr) { 149 if (ptr->addr.sin_addr.s_addr 150 == from.sin_addr.s_addr 151 && ptr->info.tsp_type == msgin.tsp_type) { 152 if (trace) 153 fprintf(fd, "\tdup "); 154 goto again; 155 } 156 } 157 msgcnt--; 158 return(&msgin); 159 } else { 160 prev = ptr; 161 ptr = ptr->p; 162 } 163 } 164 165 /* 166 * If the message was not in the linked list, it may still be 167 * coming from the network. Set the timer and wait 168 * on a select to read the next incoming message: if it is the 169 * right one, return it, otherwise insert it in the linked list. 170 */ 171 172 (void)gettimeofday(&rtout, 0); 173 timeradd(&rtout, intvl, &rtout); 174 set[0].fd = sock; 175 set[0].events = POLLIN; 176 for (;;) { 177 (void)gettimeofday(&rtime, 0); 178 timersub(&rtout, &rtime, &rwait); 179 if (rwait.tv_sec < 0) 180 rwait.tv_sec = rwait.tv_usec = 0; 181 else if (rwait.tv_sec == 0 182 && rwait.tv_usec < 1000000/CLK_TCK) 183 rwait.tv_usec = 1000000/CLK_TCK; 184 185 if (trace) { 186 fprintf(fd, "readmsg: wait %ld.%6ld at %s\n", 187 (long int)rwait.tv_sec, (long int)rwait.tv_usec, 188 date()); 189 /* Notice a full disk, as we flush trace info. 190 * It is better to flush periodically than at 191 * every line because the tracing consists of bursts 192 * of many lines. Without care, tracing slows 193 * down the code enough to break the protocol. 194 */ 195 if (rwait.tv_sec != 0 196 && EOF == fflush(fd)) 197 traceoff("Tracing ended for cause"); 198 } 199 200 if (!poll(set, 1, (int)(rwait.tv_sec * 1000 + rwait.tv_usec / 1000))) { 201 if (rwait.tv_sec == 0 && rwait.tv_usec == 0) 202 return(0); 203 continue; 204 } 205 length = sizeof(from); 206 if ((n = recvfrom(sock, &msgin, sizeof(struct tsp), 0, 207 (struct sockaddr*)(void *)&from, &length)) < 0) { 208 syslog(LOG_ERR, "recvfrom: %m"); 209 exit(EXIT_FAILURE); 210 } 211 if (n < (ssize_t)sizeof(struct tsp)) { 212 syslog(LOG_NOTICE, 213 "short packet (%lu/%lu bytes) from %s", 214 (u_long)n, (u_long)sizeof(struct tsp), 215 inet_ntoa(from.sin_addr)); 216 continue; 217 } 218 (void)gettimeofday(&from_when, (struct timezone *)0); 219 bytehostorder(&msgin); 220 221 if (msgin.tsp_vers > TSPVERSION) { 222 if (trace) { 223 fprintf(fd,"readmsg: version mismatch\n"); 224 /* should do a dump of the packet */ 225 } 226 continue; 227 } 228 229 if (memchr(msgin.tsp_name, 230 '\0', sizeof msgin.tsp_name) == NULL) { 231 syslog(LOG_NOTICE, "hostname field not NUL terminated " 232 "in packet from %s", inet_ntoa(from.sin_addr)); 233 continue; 234 } 235 236 fromnet = NULL; 237 for (ntp = nettab; ntp != NULL; ntp = ntp->next) 238 if ((ntp->mask & from.sin_addr.s_addr) == 239 ntp->net.s_addr) { 240 fromnet = ntp; 241 break; 242 } 243 244 /* 245 * drop packets from nets we are ignoring permanently 246 */ 247 if (fromnet == NULL) { 248 /* 249 * The following messages may originate on 250 * this host with an ignored network address 251 */ 252 if (msgin.tsp_type != TSP_TRACEON && 253 msgin.tsp_type != TSP_SETDATE && 254 msgin.tsp_type != TSP_MSITE && 255 msgin.tsp_type != TSP_TEST && 256 msgin.tsp_type != TSP_TRACEOFF) { 257 if (trace) { 258 fprintf(fd,"readmsg: discard null net "); 259 print(&msgin, &from); 260 } 261 continue; 262 } 263 } 264 265 /* 266 * Throw away messages coming from this machine, 267 * unless they are of some particular type. 268 * This gets rid of broadcast messages and reduces 269 * master processing time. 270 */ 271 if (!strcmp(msgin.tsp_name, hostname) 272 && msgin.tsp_type != TSP_SETDATE 273 && msgin.tsp_type != TSP_TEST 274 && msgin.tsp_type != TSP_MSITE 275 && msgin.tsp_type != TSP_TRACEON 276 && msgin.tsp_type != TSP_TRACEOFF 277 && msgin.tsp_type != TSP_LOOP) { 278 if (trace) { 279 fprintf(fd, "readmsg: discard own "); 280 print(&msgin, &from); 281 } 282 continue; 283 } 284 285 /* 286 * Send acknowledgements here; this is faster and 287 * avoids deadlocks that would occur if acks were 288 * sent from a higher level routine. Different 289 * acknowledgements are necessary, depending on 290 * status. 291 */ 292 if (fromnet == NULL) /* do not de-reference 0 */ 293 ignoreack(); 294 else if (fromnet->status == MASTER) 295 masterack(); 296 else if (fromnet->status == SLAVE) 297 slaveack(); 298 else 299 ignoreack(); 300 301 if (LOOKAT(msgin, type, machfrom, netfrom, from)) { 302 if (trace) { 303 fprintf(fd, "readmsg: "); 304 print(&msgin, &from); 305 } 306 return(&msgin); 307 } else if (++msgcnt > NHOSTS*3) { 308 309 /* The protocol gets hopelessly confused if it gets too far 310 * behind. However, it seems able to recover from all cases of lost 311 * packets. Therefore, if we are swamped, throw everything away. 312 */ 313 if (trace) 314 fprintf(fd, 315 "readmsg: discarding %d msgs\n", 316 msgcnt); 317 msgcnt = 0; 318 while ((ptr = head->p) != NULL) { 319 head->p = ptr->p; 320 free(ptr); 321 } 322 tail = head; 323 } else { 324 tail->p = malloc(sizeof(struct tsplist)); 325 tail = tail->p; 326 tail->p = NULL; 327 tail->info = msgin; 328 tail->addr = from; 329 /* timestamp msgs so SETTIMEs are correct */ 330 tail->when = from_when; 331 } 332 } 333 } 334 335 /* 336 * Send the necessary acknowledgements: 337 * only the type ACK is to be sent by a slave 338 */ 339 void 340 slaveack(void) 341 { 342 switch(msgin.tsp_type) { 343 344 case TSP_ADJTIME: 345 case TSP_SETTIME: 346 case TSP_ACCEPT: 347 case TSP_REFUSE: 348 case TSP_TRACEON: 349 case TSP_TRACEOFF: 350 case TSP_QUIT: 351 if (trace) { 352 fprintf(fd, "Slaveack: "); 353 print(&msgin, &from); 354 } 355 xmit(TSP_ACK,msgin.tsp_seq, &from); 356 break; 357 358 default: 359 if (trace) { 360 fprintf(fd, "Slaveack: no ack: "); 361 print(&msgin, &from); 362 } 363 break; 364 } 365 } 366 367 /* 368 * Certain packets may arrive from this machine on ignored networks. 369 * These packets should be acknowledged. 370 */ 371 void 372 ignoreack(void) 373 { 374 switch(msgin.tsp_type) { 375 376 case TSP_TRACEON: 377 case TSP_TRACEOFF: 378 case TSP_QUIT: 379 if (trace) { 380 fprintf(fd, "Ignoreack: "); 381 print(&msgin, &from); 382 } 383 xmit(TSP_ACK,msgin.tsp_seq, &from); 384 break; 385 386 default: 387 if (trace) { 388 fprintf(fd, "Ignoreack: no ack: "); 389 print(&msgin, &from); 390 } 391 break; 392 } 393 } 394 395 /* 396 * `masterack' sends the necessary acknowledgements 397 * to the messages received by a master 398 */ 399 void 400 masterack(void) 401 { 402 struct tsp resp; 403 404 resp = msgin; 405 resp.tsp_vers = TSPVERSION; 406 set_tsp_name(&resp, hostname); 407 408 switch(msgin.tsp_type) { 409 410 case TSP_QUIT: 411 case TSP_TRACEON: 412 case TSP_TRACEOFF: 413 case TSP_MSITEREQ: 414 if (trace) { 415 fprintf(fd, "Masterack: "); 416 print(&msgin, &from); 417 } 418 xmit(TSP_ACK,msgin.tsp_seq, &from); 419 break; 420 421 case TSP_RESOLVE: 422 case TSP_MASTERREQ: 423 if (trace) { 424 fprintf(fd, "Masterack: "); 425 print(&msgin, &from); 426 } 427 xmit(TSP_MASTERACK,msgin.tsp_seq, &from); 428 break; 429 430 default: 431 if (trace) { 432 fprintf(fd,"Masterack: no ack: "); 433 print(&msgin, &from); 434 } 435 break; 436 } 437 } 438 439 /* 440 * Print a TSP message 441 */ 442 void 443 print(struct tsp *msg, struct sockaddr_in *addr) 444 { 445 char tm[26]; 446 time_t msgtime; 447 448 if (msg->tsp_type >= TSPTYPENUMBER) { 449 fprintf(fd, "bad type (%u) on packet from %s\n", 450 msg->tsp_type, inet_ntoa(addr->sin_addr)); 451 return; 452 } 453 454 switch (msg->tsp_type) { 455 456 case TSP_LOOP: 457 fprintf(fd, "%s %d %-6u #%d %-15s %s\n", 458 tsptype[msg->tsp_type], 459 msg->tsp_vers, 460 msg->tsp_seq, 461 msg->tsp_hopcnt, 462 inet_ntoa(addr->sin_addr), 463 msg->tsp_name); 464 break; 465 466 case TSP_SETTIME: 467 case TSP_SETDATE: 468 case TSP_SETDATEREQ: 469 msgtime = msg->tsp_time.tv_sec; 470 strlcpy(tm, ctime(&msgtime)+3+1, sizeof(tm)); 471 tm[15] = '\0'; /* ugh */ 472 fprintf(fd, "%s %d %-6u %s %-15s %s\n", 473 tsptype[msg->tsp_type], 474 msg->tsp_vers, 475 msg->tsp_seq, 476 tm, 477 inet_ntoa(addr->sin_addr), 478 msg->tsp_name); 479 break; 480 481 case TSP_ADJTIME: 482 fprintf(fd, "%s %d %-6u (%ld,%ld) %-15s %s\n", 483 tsptype[msg->tsp_type], 484 msg->tsp_vers, 485 msg->tsp_seq, 486 (long)msg->tsp_time.tv_sec, 487 (long)msg->tsp_time.tv_usec, 488 inet_ntoa(addr->sin_addr), 489 msg->tsp_name); 490 break; 491 492 default: 493 fprintf(fd, "%s %d %-6u %-15s %s\n", 494 tsptype[msg->tsp_type], 495 msg->tsp_vers, 496 msg->tsp_seq, 497 inet_ntoa(addr->sin_addr), 498 msg->tsp_name); 499 break; 500 } 501 } 502