1 /* $OpenBSD: getrrsetbyname.c,v 1.10 2005/03/30 02:58:28 tedu Exp $ */ 2 3 /* 4 * Copyright (c) 2001 Jakob Schlyter. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 /* 30 * Portions Copyright (c) 1999-2001 Internet Software Consortium. 31 * 32 * Permission to use, copy, modify, and distribute this software for any 33 * purpose with or without fee is hereby granted, provided that the above 34 * copyright notice and this permission notice appear in all copies. 35 * 36 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM 37 * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL 38 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL 39 * INTERNET SOFTWARE CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, 40 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING 41 * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, 42 * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION 43 * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 44 */ 45 46 /* OPENBSD ORIGINAL: lib/libc/net/getrrsetbyname.c */ 47 48 #include "includes.h" 49 50 #ifndef HAVE_GETRRSETBYNAME 51 52 #include "getrrsetbyname.h" 53 54 #if defined(HAVE_DECL_H_ERRNO) && !HAVE_DECL_H_ERRNO 55 extern int h_errno; 56 #endif 57 58 /* We don't need multithread support here */ 59 #ifdef _THREAD_PRIVATE 60 # undef _THREAD_PRIVATE 61 #endif 62 #define _THREAD_PRIVATE(a,b,c) (c) 63 struct __res_state _res; 64 65 /* Necessary functions and macros */ 66 67 /* 68 * Inline versions of get/put short/long. Pointer is advanced. 69 * 70 * These macros demonstrate the property of C whereby it can be 71 * portable or it can be elegant but rarely both. 72 */ 73 74 #ifndef INT32SZ 75 # define INT32SZ 4 76 #endif 77 #ifndef INT16SZ 78 # define INT16SZ 2 79 #endif 80 81 #ifndef GETSHORT 82 #define GETSHORT(s, cp) { \ 83 register u_char *t_cp = (u_char *)(cp); \ 84 (s) = ((u_int16_t)t_cp[0] << 8) \ 85 | ((u_int16_t)t_cp[1]) \ 86 ; \ 87 (cp) += INT16SZ; \ 88 } 89 #endif 90 91 #ifndef GETLONG 92 #define GETLONG(l, cp) { \ 93 register u_char *t_cp = (u_char *)(cp); \ 94 (l) = ((u_int32_t)t_cp[0] << 24) \ 95 | ((u_int32_t)t_cp[1] << 16) \ 96 | ((u_int32_t)t_cp[2] << 8) \ 97 | ((u_int32_t)t_cp[3]) \ 98 ; \ 99 (cp) += INT32SZ; \ 100 } 101 #endif 102 103 /* 104 * Routines to insert/extract short/long's. 105 */ 106 107 #ifndef HAVE__GETSHORT 108 static u_int16_t 109 _getshort(msgp) 110 register const u_char *msgp; 111 { 112 register u_int16_t u; 113 114 GETSHORT(u, msgp); 115 return (u); 116 } 117 #elif defined(HAVE_DECL__GETSHORT) && (HAVE_DECL__GETSHORT == 0) 118 u_int16_t _getshort(register const u_char *); 119 #endif 120 121 #ifndef HAVE__GETLONG 122 static u_int32_t 123 _getlong(msgp) 124 register const u_char *msgp; 125 { 126 register u_int32_t u; 127 128 GETLONG(u, msgp); 129 return (u); 130 } 131 #elif defined(HAVE_DECL__GETLONG) && (HAVE_DECL__GETLONG == 0) 132 u_int32_t _getlong(register const u_char *); 133 #endif 134 135 /* ************** */ 136 137 #define ANSWER_BUFFER_SIZE 1024*64 138 139 struct dns_query { 140 char *name; 141 u_int16_t type; 142 u_int16_t class; 143 struct dns_query *next; 144 }; 145 146 struct dns_rr { 147 char *name; 148 u_int16_t type; 149 u_int16_t class; 150 u_int16_t ttl; 151 u_int16_t size; 152 void *rdata; 153 struct dns_rr *next; 154 }; 155 156 struct dns_response { 157 HEADER header; 158 struct dns_query *query; 159 struct dns_rr *answer; 160 struct dns_rr *authority; 161 struct dns_rr *additional; 162 }; 163 164 static struct dns_response *parse_dns_response(const u_char *, int); 165 static struct dns_query *parse_dns_qsection(const u_char *, int, 166 const u_char **, int); 167 static struct dns_rr *parse_dns_rrsection(const u_char *, int, const u_char **, 168 int); 169 170 static void free_dns_query(struct dns_query *); 171 static void free_dns_rr(struct dns_rr *); 172 static void free_dns_response(struct dns_response *); 173 174 static int count_dns_rr(struct dns_rr *, u_int16_t, u_int16_t); 175 176 int 177 getrrsetbyname(const char *hostname, unsigned int rdclass, 178 unsigned int rdtype, unsigned int flags, 179 struct rrsetinfo **res) 180 { 181 struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res); 182 int result; 183 struct rrsetinfo *rrset = NULL; 184 struct dns_response *response = NULL; 185 struct dns_rr *rr; 186 struct rdatainfo *rdata; 187 int length; 188 unsigned int index_ans, index_sig; 189 u_char answer[ANSWER_BUFFER_SIZE]; 190 191 /* check for invalid class and type */ 192 if (rdclass > 0xffff || rdtype > 0xffff) { 193 result = ERRSET_INVAL; 194 goto fail; 195 } 196 197 /* don't allow queries of class or type ANY */ 198 if (rdclass == 0xff || rdtype == 0xff) { 199 result = ERRSET_INVAL; 200 goto fail; 201 } 202 203 /* don't allow flags yet, unimplemented */ 204 if (flags) { 205 result = ERRSET_INVAL; 206 goto fail; 207 } 208 209 /* initialize resolver */ 210 if ((_resp->options & RES_INIT) == 0 && res_init() == -1) { 211 result = ERRSET_FAIL; 212 goto fail; 213 } 214 215 #ifdef DEBUG 216 _resp->options |= RES_DEBUG; 217 #endif /* DEBUG */ 218 219 #ifdef RES_USE_DNSSEC 220 /* turn on DNSSEC if EDNS0 is configured */ 221 if (_resp->options & RES_USE_EDNS0) 222 _resp->options |= RES_USE_DNSSEC; 223 #endif /* RES_USE_DNSEC */ 224 225 /* make query */ 226 length = res_query(hostname, (signed int) rdclass, (signed int) rdtype, 227 answer, sizeof(answer)); 228 if (length < 0) { 229 switch(h_errno) { 230 case HOST_NOT_FOUND: 231 result = ERRSET_NONAME; 232 goto fail; 233 case NO_DATA: 234 result = ERRSET_NODATA; 235 goto fail; 236 default: 237 result = ERRSET_FAIL; 238 goto fail; 239 } 240 } 241 242 /* parse result */ 243 response = parse_dns_response(answer, length); 244 if (response == NULL) { 245 result = ERRSET_FAIL; 246 goto fail; 247 } 248 249 if (response->header.qdcount != 1) { 250 result = ERRSET_FAIL; 251 goto fail; 252 } 253 254 /* initialize rrset */ 255 rrset = calloc(1, sizeof(struct rrsetinfo)); 256 if (rrset == NULL) { 257 result = ERRSET_NOMEMORY; 258 goto fail; 259 } 260 rrset->rri_rdclass = response->query->class; 261 rrset->rri_rdtype = response->query->type; 262 rrset->rri_ttl = response->answer->ttl; 263 rrset->rri_nrdatas = response->header.ancount; 264 265 #ifdef HAVE_HEADER_AD 266 /* check for authenticated data */ 267 if (response->header.ad == 1) 268 rrset->rri_flags |= RRSET_VALIDATED; 269 #endif 270 271 /* copy name from answer section */ 272 rrset->rri_name = strdup(response->answer->name); 273 if (rrset->rri_name == NULL) { 274 result = ERRSET_NOMEMORY; 275 goto fail; 276 } 277 278 /* count answers */ 279 rrset->rri_nrdatas = count_dns_rr(response->answer, rrset->rri_rdclass, 280 rrset->rri_rdtype); 281 rrset->rri_nsigs = count_dns_rr(response->answer, rrset->rri_rdclass, 282 T_SIG); 283 284 /* allocate memory for answers */ 285 rrset->rri_rdatas = calloc(rrset->rri_nrdatas, 286 sizeof(struct rdatainfo)); 287 if (rrset->rri_rdatas == NULL) { 288 result = ERRSET_NOMEMORY; 289 goto fail; 290 } 291 292 /* allocate memory for signatures */ 293 rrset->rri_sigs = calloc(rrset->rri_nsigs, sizeof(struct rdatainfo)); 294 if (rrset->rri_sigs == NULL) { 295 result = ERRSET_NOMEMORY; 296 goto fail; 297 } 298 299 /* copy answers & signatures */ 300 for (rr = response->answer, index_ans = 0, index_sig = 0; 301 rr; rr = rr->next) { 302 303 rdata = NULL; 304 305 if (rr->class == rrset->rri_rdclass && 306 rr->type == rrset->rri_rdtype) 307 rdata = &rrset->rri_rdatas[index_ans++]; 308 309 if (rr->class == rrset->rri_rdclass && 310 rr->type == T_SIG) 311 rdata = &rrset->rri_sigs[index_sig++]; 312 313 if (rdata) { 314 rdata->rdi_length = rr->size; 315 rdata->rdi_data = malloc(rr->size); 316 317 if (rdata->rdi_data == NULL) { 318 result = ERRSET_NOMEMORY; 319 goto fail; 320 } 321 memcpy(rdata->rdi_data, rr->rdata, rr->size); 322 } 323 } 324 free_dns_response(response); 325 326 *res = rrset; 327 return (ERRSET_SUCCESS); 328 329 fail: 330 if (rrset != NULL) 331 freerrset(rrset); 332 if (response != NULL) 333 free_dns_response(response); 334 return (result); 335 } 336 337 void 338 freerrset(struct rrsetinfo *rrset) 339 { 340 u_int16_t i; 341 342 if (rrset == NULL) 343 return; 344 345 if (rrset->rri_rdatas) { 346 for (i = 0; i < rrset->rri_nrdatas; i++) { 347 if (rrset->rri_rdatas[i].rdi_data == NULL) 348 break; 349 free(rrset->rri_rdatas[i].rdi_data); 350 } 351 free(rrset->rri_rdatas); 352 } 353 354 if (rrset->rri_sigs) { 355 for (i = 0; i < rrset->rri_nsigs; i++) { 356 if (rrset->rri_sigs[i].rdi_data == NULL) 357 break; 358 free(rrset->rri_sigs[i].rdi_data); 359 } 360 free(rrset->rri_sigs); 361 } 362 363 if (rrset->rri_name) 364 free(rrset->rri_name); 365 free(rrset); 366 } 367 368 /* 369 * DNS response parsing routines 370 */ 371 static struct dns_response * 372 parse_dns_response(const u_char *answer, int size) 373 { 374 struct dns_response *resp; 375 const u_char *cp; 376 377 /* allocate memory for the response */ 378 resp = calloc(1, sizeof(*resp)); 379 if (resp == NULL) 380 return (NULL); 381 382 /* initialize current pointer */ 383 cp = answer; 384 385 /* copy header */ 386 memcpy(&resp->header, cp, HFIXEDSZ); 387 cp += HFIXEDSZ; 388 389 /* fix header byte order */ 390 resp->header.qdcount = ntohs(resp->header.qdcount); 391 resp->header.ancount = ntohs(resp->header.ancount); 392 resp->header.nscount = ntohs(resp->header.nscount); 393 resp->header.arcount = ntohs(resp->header.arcount); 394 395 /* there must be at least one query */ 396 if (resp->header.qdcount < 1) { 397 free_dns_response(resp); 398 return (NULL); 399 } 400 401 /* parse query section */ 402 resp->query = parse_dns_qsection(answer, size, &cp, 403 resp->header.qdcount); 404 if (resp->header.qdcount && resp->query == NULL) { 405 free_dns_response(resp); 406 return (NULL); 407 } 408 409 /* parse answer section */ 410 resp->answer = parse_dns_rrsection(answer, size, &cp, 411 resp->header.ancount); 412 if (resp->header.ancount && resp->answer == NULL) { 413 free_dns_response(resp); 414 return (NULL); 415 } 416 417 /* parse authority section */ 418 resp->authority = parse_dns_rrsection(answer, size, &cp, 419 resp->header.nscount); 420 if (resp->header.nscount && resp->authority == NULL) { 421 free_dns_response(resp); 422 return (NULL); 423 } 424 425 /* parse additional section */ 426 resp->additional = parse_dns_rrsection(answer, size, &cp, 427 resp->header.arcount); 428 if (resp->header.arcount && resp->additional == NULL) { 429 free_dns_response(resp); 430 return (NULL); 431 } 432 433 return (resp); 434 } 435 436 static struct dns_query * 437 parse_dns_qsection(const u_char *answer, int size, const u_char **cp, int count) 438 { 439 struct dns_query *head, *curr, *prev; 440 int i, length; 441 char name[MAXDNAME]; 442 443 for (i = 1, head = NULL, prev = NULL; i <= count; i++, prev = curr) { 444 445 /* allocate and initialize struct */ 446 curr = calloc(1, sizeof(struct dns_query)); 447 if (curr == NULL) { 448 free_dns_query(head); 449 return (NULL); 450 } 451 if (head == NULL) 452 head = curr; 453 if (prev != NULL) 454 prev->next = curr; 455 456 /* name */ 457 length = dn_expand(answer, answer + size, *cp, name, 458 sizeof(name)); 459 if (length < 0) { 460 free_dns_query(head); 461 return (NULL); 462 } 463 curr->name = strdup(name); 464 if (curr->name == NULL) { 465 free_dns_query(head); 466 return (NULL); 467 } 468 *cp += length; 469 470 /* type */ 471 curr->type = _getshort(*cp); 472 *cp += INT16SZ; 473 474 /* class */ 475 curr->class = _getshort(*cp); 476 *cp += INT16SZ; 477 } 478 479 return (head); 480 } 481 482 static struct dns_rr * 483 parse_dns_rrsection(const u_char *answer, int size, const u_char **cp, 484 int count) 485 { 486 struct dns_rr *head, *curr, *prev; 487 int i, length; 488 char name[MAXDNAME]; 489 490 for (i = 1, head = NULL, prev = NULL; i <= count; i++, prev = curr) { 491 492 /* allocate and initialize struct */ 493 curr = calloc(1, sizeof(struct dns_rr)); 494 if (curr == NULL) { 495 free_dns_rr(head); 496 return (NULL); 497 } 498 if (head == NULL) 499 head = curr; 500 if (prev != NULL) 501 prev->next = curr; 502 503 /* name */ 504 length = dn_expand(answer, answer + size, *cp, name, 505 sizeof(name)); 506 if (length < 0) { 507 free_dns_rr(head); 508 return (NULL); 509 } 510 curr->name = strdup(name); 511 if (curr->name == NULL) { 512 free_dns_rr(head); 513 return (NULL); 514 } 515 *cp += length; 516 517 /* type */ 518 curr->type = _getshort(*cp); 519 *cp += INT16SZ; 520 521 /* class */ 522 curr->class = _getshort(*cp); 523 *cp += INT16SZ; 524 525 /* ttl */ 526 curr->ttl = _getlong(*cp); 527 *cp += INT32SZ; 528 529 /* rdata size */ 530 curr->size = _getshort(*cp); 531 *cp += INT16SZ; 532 533 /* rdata itself */ 534 curr->rdata = malloc(curr->size); 535 if (curr->rdata == NULL) { 536 free_dns_rr(head); 537 return (NULL); 538 } 539 memcpy(curr->rdata, *cp, curr->size); 540 *cp += curr->size; 541 } 542 543 return (head); 544 } 545 546 static void 547 free_dns_query(struct dns_query *p) 548 { 549 if (p == NULL) 550 return; 551 552 if (p->name) 553 free(p->name); 554 free_dns_query(p->next); 555 free(p); 556 } 557 558 static void 559 free_dns_rr(struct dns_rr *p) 560 { 561 if (p == NULL) 562 return; 563 564 if (p->name) 565 free(p->name); 566 if (p->rdata) 567 free(p->rdata); 568 free_dns_rr(p->next); 569 free(p); 570 } 571 572 static void 573 free_dns_response(struct dns_response *p) 574 { 575 if (p == NULL) 576 return; 577 578 free_dns_query(p->query); 579 free_dns_rr(p->answer); 580 free_dns_rr(p->authority); 581 free_dns_rr(p->additional); 582 free(p); 583 } 584 585 static int 586 count_dns_rr(struct dns_rr *p, u_int16_t class, u_int16_t type) 587 { 588 int n = 0; 589 590 while(p) { 591 if (p->class == class && p->type == type) 592 n++; 593 p = p->next; 594 } 595 596 return (n); 597 } 598 599 #endif /* !defined(HAVE_GETRRSETBYNAME) */ 600