1 /* $OpenBSD: asr.c,v 1.54 2016/06/18 15:25:28 reyk Exp $ */ 2 /* 3 * Copyright (c) 2010-2012 Eric Faurot <eric@openbsd.org> 4 * 5 * Permission to use, copy, modify, and distribute this software for any 6 * purpose with or without fee is hereby granted, provided that the above 7 * copyright notice and this permission notice appear in all copies. 8 * 9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 16 */ 17 18 #include <sys/types.h> 19 #include <sys/socket.h> 20 #include <sys/stat.h> 21 #include <netinet/in.h> 22 #include <arpa/inet.h> 23 #include <arpa/nameser.h> 24 #include <netdb.h> 25 26 #include <asr.h> 27 #include <errno.h> 28 #include <fcntl.h> 29 #include <resolv.h> 30 #include <poll.h> 31 #include <stdio.h> 32 #include <stdlib.h> 33 #include <string.h> 34 #include <unistd.h> 35 #include <limits.h> 36 37 #include "asr_private.h" 38 39 #include "thread_private.h" 40 41 #define DEFAULT_CONF "lookup file\n" 42 #define DEFAULT_LOOKUP "lookup bind file" 43 44 #define RELOAD_DELAY 15 /* seconds */ 45 46 static void asr_check_reload(struct asr *); 47 static struct asr_ctx *asr_ctx_create(void); 48 static void asr_ctx_ref(struct asr_ctx *); 49 static void asr_ctx_free(struct asr_ctx *); 50 static int asr_ctx_add_searchdomain(struct asr_ctx *, const char *); 51 static int asr_ctx_from_file(struct asr_ctx *, const char *); 52 static int asr_ctx_from_string(struct asr_ctx *, const char *); 53 static int asr_ctx_parse(struct asr_ctx *, const char *); 54 static int asr_parse_nameserver(struct sockaddr *, const char *); 55 static int asr_ndots(const char *); 56 static void pass0(char **, int, struct asr_ctx *); 57 static int strsplit(char *, char **, int); 58 static void asr_ctx_envopts(struct asr_ctx *); 59 static void *__THREAD_NAME(_asr); 60 61 static struct asr *_asr = NULL; 62 63 /* Allocate and configure an async "resolver". */ 64 static void * 65 _asr_resolver(void) 66 { 67 static int init = 0; 68 struct asr *asr; 69 70 if (init == 0) { 71 #ifdef DEBUG 72 if (getenv("ASR_DEBUG")) 73 _asr_debug = stderr; 74 #endif 75 init = 1; 76 } 77 78 if ((asr = calloc(1, sizeof(*asr))) == NULL) 79 goto fail; 80 81 asr_check_reload(asr); 82 if (asr->a_ctx == NULL) { 83 if ((asr->a_ctx = asr_ctx_create()) == NULL) 84 goto fail; 85 if (asr_ctx_from_string(asr->a_ctx, DEFAULT_CONF) == -1) 86 goto fail; 87 asr_ctx_envopts(asr->a_ctx); 88 } 89 90 #ifdef DEBUG 91 _asr_dump_config(_asr_debug, asr); 92 #endif 93 return (asr); 94 95 fail: 96 if (asr) { 97 if (asr->a_ctx) 98 asr_ctx_free(asr->a_ctx); 99 free(asr); 100 } 101 102 return (NULL); 103 } 104 105 /* 106 * Free the "asr" async resolver (or the thread-local resolver if NULL). 107 * Drop the reference to the current context. 108 */ 109 void 110 _asr_resolver_done(void *arg) 111 { 112 struct asr *asr = arg; 113 struct asr **priv; 114 115 if (asr == NULL) { 116 priv = _THREAD_PRIVATE(_asr, _asr, &_asr); 117 if (*priv == NULL) 118 return; 119 asr = *priv; 120 *priv = NULL; 121 } 122 123 _asr_ctx_unref(asr->a_ctx); 124 free(asr); 125 } 126 127 /* 128 * Cancel an async query. 129 */ 130 void 131 asr_abort(struct asr_query *as) 132 { 133 _asr_async_free(as); 134 } 135 136 /* 137 * Resume the "as" async query resolution. Return one of ASYNC_COND, 138 * or ASYNC_DONE and put query-specific return values in the user-allocated 139 * memory at "ar". 140 */ 141 int 142 asr_run(struct asr_query *as, struct asr_result *ar) 143 { 144 int r, saved_errno = errno; 145 146 DPRINT("asr: asr_run(%p, %p) %s ctx=[%p]\n", as, ar, 147 _asr_querystr(as->as_type), as->as_ctx); 148 r = as->as_run(as, ar); 149 150 DPRINT("asr: asr_run(%p, %p) -> %s", as, ar, _asr_transitionstr(r)); 151 #ifdef DEBUG 152 if (r == ASYNC_COND) 153 #endif 154 DPRINT(" fd=%i timeout=%i", ar->ar_fd, ar->ar_timeout); 155 DPRINT("\n"); 156 if (r == ASYNC_DONE) 157 _asr_async_free(as); 158 159 errno = saved_errno; 160 161 return (r); 162 } 163 DEF_WEAK(asr_run); 164 165 /* 166 * Same as above, but run in a loop that handles the fd conditions result. 167 */ 168 int 169 asr_run_sync(struct asr_query *as, struct asr_result *ar) 170 { 171 struct pollfd fds[1]; 172 struct timespec pollstart, pollend, elapsed; 173 int timeout, r, p, saved_errno = errno; 174 175 while ((r = asr_run(as, ar)) == ASYNC_COND) { 176 fds[0].fd = ar->ar_fd; 177 fds[0].events = (ar->ar_cond == ASR_WANT_READ) ? POLLIN:POLLOUT; 178 179 timeout = ar->ar_timeout; 180 again: 181 if (clock_gettime(CLOCK_MONOTONIC, &pollstart)) 182 break; 183 p = poll(fds, 1, timeout); 184 if (p == -1 && errno == EINTR) { 185 if (clock_gettime(CLOCK_MONOTONIC, &pollend)) 186 break; 187 188 timespecsub(&pollend, &pollstart, &elapsed); 189 timeout -= (elapsed.tv_sec * 1000) + 190 (elapsed.tv_nsec / 1000000); 191 if (timeout < 1) 192 break; 193 goto again; 194 } 195 196 /* 197 * Otherwise, just ignore the error and let asr_run() 198 * catch the failure. 199 */ 200 } 201 202 errno = saved_errno; 203 204 return (r); 205 } 206 DEF_WEAK(asr_run_sync); 207 208 /* 209 * Create a new async request of the given "type" on the async context "ac". 210 * Take a reference on it so it does not gets deleted while the async query 211 * is running. 212 */ 213 struct asr_query * 214 _asr_async_new(struct asr_ctx *ac, int type) 215 { 216 struct asr_query *as; 217 218 DPRINT("asr: asr_async_new(ctx=%p) type=%i refcount=%i\n", ac, type, 219 ac ? ac->ac_refcount : 0); 220 if (ac == NULL || (as = calloc(1, sizeof(*as))) == NULL) 221 return (NULL); 222 223 ac->ac_refcount += 1; 224 as->as_ctx = ac; 225 as->as_fd = -1; 226 as->as_type = type; 227 as->as_state = ASR_STATE_INIT; 228 229 return (as); 230 } 231 232 /* 233 * Free an async query and unref the associated context. 234 */ 235 void 236 _asr_async_free(struct asr_query *as) 237 { 238 DPRINT("asr: asr_async_free(%p)\n", as); 239 switch (as->as_type) { 240 case ASR_SEND: 241 if (as->as_fd != -1) 242 close(as->as_fd); 243 if (as->as.dns.obuf && !(as->as.dns.flags & ASYNC_EXTOBUF)) 244 free(as->as.dns.obuf); 245 if (as->as.dns.ibuf) 246 free(as->as.dns.ibuf); 247 if (as->as.dns.dname) 248 free(as->as.dns.dname); 249 break; 250 251 case ASR_SEARCH: 252 if (as->as.search.subq) 253 _asr_async_free(as->as.search.subq); 254 if (as->as.search.name) 255 free(as->as.search.name); 256 break; 257 258 case ASR_GETRRSETBYNAME: 259 if (as->as.rrset.subq) 260 _asr_async_free(as->as.rrset.subq); 261 if (as->as.rrset.name) 262 free(as->as.rrset.name); 263 break; 264 265 case ASR_GETHOSTBYNAME: 266 case ASR_GETHOSTBYADDR: 267 if (as->as.hostnamadr.subq) 268 _asr_async_free(as->as.hostnamadr.subq); 269 if (as->as.hostnamadr.name) 270 free(as->as.hostnamadr.name); 271 break; 272 273 case ASR_GETNETBYNAME: 274 case ASR_GETNETBYADDR: 275 if (as->as.netnamadr.subq) 276 _asr_async_free(as->as.netnamadr.subq); 277 if (as->as.netnamadr.name) 278 free(as->as.netnamadr.name); 279 break; 280 281 case ASR_GETADDRINFO: 282 if (as->as.ai.subq) 283 _asr_async_free(as->as.ai.subq); 284 if (as->as.ai.aifirst) 285 freeaddrinfo(as->as.ai.aifirst); 286 if (as->as.ai.hostname) 287 free(as->as.ai.hostname); 288 if (as->as.ai.servname) 289 free(as->as.ai.servname); 290 if (as->as.ai.fqdn) 291 free(as->as.ai.fqdn); 292 break; 293 294 case ASR_GETNAMEINFO: 295 if (as->as.ni.subq) 296 _asr_async_free(as->as.ni.subq); 297 break; 298 } 299 300 _asr_ctx_unref(as->as_ctx); 301 free(as); 302 } 303 304 /* 305 * Get a context from the given resolver. This takes a new reference to 306 * the returned context, which *must* be explicitely dropped when done 307 * using this context. 308 */ 309 struct asr_ctx * 310 _asr_use_resolver(void *arg) 311 { 312 struct asr *asr = arg; 313 struct asr **priv; 314 315 if (asr == NULL) { 316 DPRINT("using thread-local resolver\n"); 317 priv = _THREAD_PRIVATE(_asr, _asr, &_asr); 318 if (*priv == NULL) { 319 DPRINT("setting up thread-local resolver\n"); 320 *priv = _asr_resolver(); 321 } 322 asr = *priv; 323 } 324 if (asr != NULL) { 325 asr_check_reload(asr); 326 asr_ctx_ref(asr->a_ctx); 327 return (asr->a_ctx); 328 } 329 return (NULL); 330 } 331 332 static void 333 asr_ctx_ref(struct asr_ctx *ac) 334 { 335 DPRINT("asr: asr_ctx_ref(ctx=%p) refcount=%i\n", ac, ac->ac_refcount); 336 ac->ac_refcount += 1; 337 } 338 339 /* 340 * Drop a reference to an async context, freeing it if the reference 341 * count drops to 0. 342 */ 343 void 344 _asr_ctx_unref(struct asr_ctx *ac) 345 { 346 DPRINT("asr: asr_ctx_unref(ctx=%p) refcount=%i\n", ac, 347 ac ? ac->ac_refcount : 0); 348 if (ac == NULL) 349 return; 350 if (--ac->ac_refcount) 351 return; 352 353 asr_ctx_free(ac); 354 } 355 356 static void 357 asr_ctx_free(struct asr_ctx *ac) 358 { 359 int i; 360 361 if (ac->ac_domain) 362 free(ac->ac_domain); 363 for (i = 0; i < ASR_MAXNS; i++) 364 free(ac->ac_ns[i]); 365 for (i = 0; i < ASR_MAXDOM; i++) 366 free(ac->ac_dom[i]); 367 368 free(ac); 369 } 370 371 /* 372 * Reload the configuration file if it has changed on disk. 373 */ 374 static void 375 asr_check_reload(struct asr *asr) 376 { 377 struct asr_ctx *ac; 378 struct stat st; 379 struct timespec ts; 380 pid_t pid; 381 382 pid = getpid(); 383 if (pid != asr->a_pid) { 384 asr->a_pid = pid; 385 asr->a_rtime = 0; 386 } 387 388 if (clock_gettime(CLOCK_MONOTONIC, &ts) == -1) 389 return; 390 391 if ((ts.tv_sec - asr->a_rtime) < RELOAD_DELAY && asr->a_rtime != 0) 392 return; 393 asr->a_rtime = ts.tv_sec; 394 395 DPRINT("asr: checking for update of \"%s\"\n", _PATH_RESCONF); 396 if (stat(_PATH_RESCONF, &st) == -1 || 397 asr->a_mtime == st.st_mtime || 398 (ac = asr_ctx_create()) == NULL) 399 return; 400 asr->a_mtime = st.st_mtime; 401 402 DPRINT("asr: reloading config file\n"); 403 if (asr_ctx_from_file(ac, _PATH_RESCONF) == -1) { 404 asr_ctx_free(ac); 405 return; 406 } 407 408 asr_ctx_envopts(ac); 409 if (asr->a_ctx) 410 _asr_ctx_unref(asr->a_ctx); 411 asr->a_ctx = ac; 412 } 413 414 /* 415 * Construct a fully-qualified domain name for the given name and domain. 416 * If "name" ends with a '.' it is considered as a FQDN by itself. 417 * Otherwise, the domain, which must be a FQDN, is appended to "name" (it 418 * may have a leading dot which would be ignored). If the domain is null, 419 * then "." is used. Return the length of the constructed FQDN or (0) on 420 * error. 421 */ 422 size_t 423 _asr_make_fqdn(const char *name, const char *domain, char *buf, size_t buflen) 424 { 425 size_t len; 426 427 if (domain == NULL) 428 domain = "."; 429 else if ((len = strlen(domain)) == 0) 430 return (0); 431 else if (domain[len -1] != '.') 432 return (0); 433 434 len = strlen(name); 435 if (len == 0) { 436 if (strlcpy(buf, domain, buflen) >= buflen) 437 return (0); 438 } else if (name[len - 1] != '.') { 439 if (domain[0] == '.') 440 domain += 1; 441 if (strlcpy(buf, name, buflen) >= buflen || 442 strlcat(buf, ".", buflen) >= buflen || 443 strlcat(buf, domain, buflen) >= buflen) 444 return (0); 445 } else { 446 if (strlcpy(buf, name, buflen) >= buflen) 447 return (0); 448 } 449 450 return (strlen(buf)); 451 } 452 453 /* 454 * Count the dots in a string. 455 */ 456 static int 457 asr_ndots(const char *s) 458 { 459 int n; 460 461 for (n = 0; *s; s++) 462 if (*s == '.') 463 n += 1; 464 465 return (n); 466 } 467 468 /* 469 * Allocate a new empty context. 470 */ 471 static struct asr_ctx * 472 asr_ctx_create(void) 473 { 474 struct asr_ctx *ac; 475 476 if ((ac = calloc(1, sizeof(*ac))) == NULL) 477 return (NULL); 478 479 ac->ac_options = RES_RECURSE | RES_DEFNAMES | RES_DNSRCH; 480 ac->ac_refcount = 1; 481 ac->ac_ndots = 1; 482 ac->ac_family[0] = AF_INET; 483 ac->ac_family[1] = AF_INET6; 484 ac->ac_family[2] = -1; 485 486 ac->ac_nscount = 0; 487 ac->ac_nstimeout = 5; 488 ac->ac_nsretries = 4; 489 490 return (ac); 491 } 492 493 struct asr_ctx * 494 _asr_no_resolver(void) 495 { 496 return asr_ctx_create(); 497 } 498 499 /* 500 * Add a search domain to the async context. 501 */ 502 static int 503 asr_ctx_add_searchdomain(struct asr_ctx *ac, const char *domain) 504 { 505 char buf[MAXDNAME]; 506 507 if (ac->ac_domcount == ASR_MAXDOM) 508 return (-1); 509 510 if (_asr_make_fqdn(domain, NULL, buf, sizeof(buf)) == 0) 511 return (-1); 512 513 if ((ac->ac_dom[ac->ac_domcount] = strdup(buf)) == NULL) 514 return (0); 515 516 ac->ac_domcount += 1; 517 518 return (1); 519 } 520 521 static int 522 strsplit(char *line, char **tokens, int ntokens) 523 { 524 int ntok; 525 char *cp, **tp; 526 527 for (cp = line, tp = tokens, ntok = 0; 528 ntok < ntokens && (*tp = strsep(&cp, " \t")) != NULL; ) 529 if (**tp != '\0') { 530 tp++; 531 ntok++; 532 } 533 534 return (ntok); 535 } 536 537 /* 538 * Pass on a split config line. 539 */ 540 static void 541 pass0(char **tok, int n, struct asr_ctx *ac) 542 { 543 int i, j, d; 544 const char *e; 545 struct sockaddr_storage ss; 546 547 if (!strcmp(tok[0], "nameserver")) { 548 if (ac->ac_nscount == ASR_MAXNS) 549 return; 550 if (n != 2) 551 return; 552 if (asr_parse_nameserver((struct sockaddr *)&ss, tok[1])) 553 return; 554 if ((ac->ac_ns[ac->ac_nscount] = calloc(1, ss.ss_len)) == NULL) 555 return; 556 memmove(ac->ac_ns[ac->ac_nscount], &ss, ss.ss_len); 557 ac->ac_nscount += 1; 558 559 } else if (!strcmp(tok[0], "domain")) { 560 if (n != 2) 561 return; 562 if (ac->ac_domain) 563 return; 564 ac->ac_domain = strdup(tok[1]); 565 566 } else if (!strcmp(tok[0], "lookup")) { 567 /* ensure that each lookup is only given once */ 568 for (i = 1; i < n; i++) 569 for (j = i + 1; j < n; j++) 570 if (!strcmp(tok[i], tok[j])) 571 return; 572 ac->ac_dbcount = 0; 573 for (i = 1; i < n && ac->ac_dbcount < ASR_MAXDB; i++) { 574 if (!strcmp(tok[i], "yp")) { 575 /* silently deprecated */ 576 } else if (!strcmp(tok[i], "bind")) 577 ac->ac_db[ac->ac_dbcount++] = ASR_DB_DNS; 578 else if (!strcmp(tok[i], "file")) 579 ac->ac_db[ac->ac_dbcount++] = ASR_DB_FILE; 580 } 581 } else if (!strcmp(tok[0], "search")) { 582 /* resolv.conf says the last line wins */ 583 for (i = 0; i < ASR_MAXDOM; i++) { 584 free(ac->ac_dom[i]); 585 ac->ac_dom[i] = NULL; 586 } 587 ac->ac_domcount = 0; 588 for (i = 1; i < n; i++) 589 asr_ctx_add_searchdomain(ac, tok[i]); 590 591 } else if (!strcmp(tok[0], "family")) { 592 if (n == 1 || n > 3) 593 return; 594 for (i = 1; i < n; i++) 595 if (strcmp(tok[i], "inet4") && strcmp(tok[i], "inet6")) 596 return; 597 for (i = 1; i < n; i++) 598 ac->ac_family[i - 1] = strcmp(tok[i], "inet4") ? \ 599 AF_INET6 : AF_INET; 600 ac->ac_family[i - 1] = -1; 601 602 } else if (!strcmp(tok[0], "options")) { 603 for (i = 1; i < n; i++) { 604 if (!strcmp(tok[i], "tcp")) 605 ac->ac_options |= RES_USEVC; 606 else if ((!strncmp(tok[i], "ndots:", 6))) { 607 e = NULL; 608 d = strtonum(tok[i] + 6, 1, 16, &e); 609 if (e == NULL) 610 ac->ac_ndots = d; 611 } 612 } 613 } 614 } 615 616 /* 617 * Setup an async context with the config specified in the string "str". 618 */ 619 static int 620 asr_ctx_from_string(struct asr_ctx *ac, const char *str) 621 { 622 char buf[512], *ch; 623 624 asr_ctx_parse(ac, str); 625 626 if (ac->ac_dbcount == 0) { 627 /* No lookup directive */ 628 asr_ctx_parse(ac, DEFAULT_LOOKUP); 629 } 630 631 if (ac->ac_nscount == 0) 632 asr_ctx_parse(ac, "nameserver 127.0.0.1"); 633 634 if (ac->ac_domain == NULL) 635 if (gethostname(buf, sizeof buf) == 0) { 636 ch = strchr(buf, '.'); 637 if (ch) 638 ac->ac_domain = strdup(ch + 1); 639 else /* Assume root. see resolv.conf(5) */ 640 ac->ac_domain = strdup(""); 641 } 642 643 /* If no search domain was specified, use the local subdomains */ 644 if (ac->ac_domcount == 0) 645 for (ch = ac->ac_domain; ch; ) { 646 asr_ctx_add_searchdomain(ac, ch); 647 ch = strchr(ch, '.'); 648 if (ch && asr_ndots(++ch) == 0) 649 break; 650 } 651 652 return (0); 653 } 654 655 /* 656 * Setup the "ac" async context from the file at location "path". 657 */ 658 static int 659 asr_ctx_from_file(struct asr_ctx *ac, const char *path) 660 { 661 FILE *cf; 662 char buf[4096]; 663 ssize_t r; 664 665 cf = fopen(path, "re"); 666 if (cf == NULL) 667 return (-1); 668 669 r = fread(buf, 1, sizeof buf - 1, cf); 670 if (feof(cf) == 0) { 671 DPRINT("asr: config file too long: \"%s\"\n", path); 672 r = -1; 673 } 674 fclose(cf); 675 if (r == -1) 676 return (-1); 677 buf[r] = '\0'; 678 679 return asr_ctx_from_string(ac, buf); 680 } 681 682 /* 683 * Parse lines in the configuration string. For each one, split it into 684 * tokens and pass them to "pass0" for processing. 685 */ 686 static int 687 asr_ctx_parse(struct asr_ctx *ac, const char *str) 688 { 689 size_t len; 690 const char *line; 691 char buf[1024]; 692 char *tok[10]; 693 int ntok; 694 695 line = str; 696 while (*line) { 697 len = strcspn(line, "\n\0"); 698 if (len < sizeof buf) { 699 memmove(buf, line, len); 700 buf[len] = '\0'; 701 } else 702 buf[0] = '\0'; 703 line += len; 704 if (*line == '\n') 705 line++; 706 buf[strcspn(buf, ";#")] = '\0'; 707 if ((ntok = strsplit(buf, tok, 10)) == 0) 708 continue; 709 710 pass0(tok, ntok, ac); 711 } 712 713 return (0); 714 } 715 716 /* 717 * Check for environment variables altering the configuration as described 718 * in resolv.conf(5). Although not documented there, this feature is disabled 719 * for setuid/setgid programs. 720 */ 721 static void 722 asr_ctx_envopts(struct asr_ctx *ac) 723 { 724 char buf[4096], *e; 725 size_t s; 726 727 if (issetugid()) { 728 ac->ac_options |= RES_NOALIASES; 729 return; 730 } 731 732 if ((e = getenv("RES_OPTIONS")) != NULL) { 733 strlcpy(buf, "options ", sizeof buf); 734 strlcat(buf, e, sizeof buf); 735 s = strlcat(buf, "\n", sizeof buf); 736 if (s < sizeof buf) 737 asr_ctx_parse(ac, buf); 738 } 739 740 if ((e = getenv("LOCALDOMAIN")) != NULL) { 741 strlcpy(buf, "search ", sizeof buf); 742 strlcat(buf, e, sizeof buf); 743 s = strlcat(buf, "\n", sizeof buf); 744 if (s < sizeof buf) 745 asr_ctx_parse(ac, buf); 746 } 747 } 748 749 /* 750 * Parse a resolv.conf(5) nameserver string into a sockaddr. 751 */ 752 static int 753 asr_parse_nameserver(struct sockaddr *sa, const char *s) 754 { 755 in_port_t portno = 53; 756 757 if (_asr_sockaddr_from_str(sa, PF_UNSPEC, s) == -1) 758 return (-1); 759 760 if (sa->sa_family == PF_INET) 761 ((struct sockaddr_in *)sa)->sin_port = htons(portno); 762 else if (sa->sa_family == PF_INET6) 763 ((struct sockaddr_in6 *)sa)->sin6_port = htons(portno); 764 765 return (0); 766 } 767 768 /* 769 * Turn a (uncompressed) DNS domain name into a regular nul-terminated string 770 * where labels are separated by dots. The result is put into the "buf" buffer, 771 * truncated if it exceeds "max" chars. The function returns "buf". 772 */ 773 char * 774 _asr_strdname(const char *_dname, char *buf, size_t max) 775 { 776 const unsigned char *dname = _dname; 777 char *res; 778 size_t left, n, count; 779 780 if (_dname[0] == 0) { 781 strlcpy(buf, ".", max); 782 return buf; 783 } 784 785 res = buf; 786 left = max - 1; 787 for (n = 0; dname[0] && left; n += dname[0]) { 788 count = (dname[0] < (left - 1)) ? dname[0] : (left - 1); 789 memmove(buf, dname + 1, count); 790 dname += dname[0] + 1; 791 left -= count; 792 buf += count; 793 if (left) { 794 left -= 1; 795 *buf++ = '.'; 796 } 797 } 798 buf[0] = 0; 799 800 return (res); 801 } 802 803 /* 804 * Read and split the next line from the given namedb file. 805 * Return -1 on error, or put the result in the "tokens" array of 806 * size "ntoken" and returns the number of token on the line. 807 */ 808 int 809 _asr_parse_namedb_line(FILE *file, char **tokens, int ntoken, char *lbuf, size_t sz) 810 { 811 size_t len; 812 char *buf; 813 int ntok; 814 815 again: 816 if ((buf = fgetln(file, &len)) == NULL) 817 return (-1); 818 819 if (len >= sz) 820 goto again; 821 822 if (buf[len - 1] == '\n') 823 len--; 824 else { 825 memcpy(lbuf, buf, len); 826 buf = lbuf; 827 } 828 829 buf[len] = '\0'; 830 buf[strcspn(buf, "#")] = '\0'; 831 if ((ntok = strsplit(buf, tokens, ntoken)) == 0) 832 goto again; 833 834 return (ntok); 835 } 836 837 /* 838 * Update the async context so that it uses the next configured DB. 839 * Return 0 on success, or -1 if no more DBs is available. 840 */ 841 int 842 _asr_iter_db(struct asr_query *as) 843 { 844 if (as->as_db_idx >= as->as_ctx->ac_dbcount) { 845 DPRINT("asr_iter_db: done\n"); 846 return (-1); 847 } 848 849 as->as_db_idx += 1; 850 DPRINT("asr_iter_db: %i\n", as->as_db_idx); 851 852 return (0); 853 } 854