openbsd-compat/getrrsetbyname.c

   1 /* OPENBSD ORIGINAL: lib/libc/net/getrrsetbyname.c */
   2
   3 /* $OpenBSD: getrrsetbyname.c,v 1.10 2005/03/30 02:58:28 tedu Exp $ */
   4
   5 /*
   6  * Copyright (c) 2001 Jakob Schlyter. All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  *
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  20  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  21  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  22  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  23  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  24  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  28  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29  */
  30
  31 /*
  32  * Portions Copyright (c) 1999-2001 Internet Software Consortium.
  33  *
  34  * Permission to use, copy, modify, and distribute this software for any
  35  * purpose with or without fee is hereby granted, provided that the above
  36  * copyright notice and this permission notice appear in all copies.
  37  *
  38  * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM
  39  * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
  40  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
  41  * INTERNET SOFTWARE CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT,
  42  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
  43  * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
  44  * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
  45  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  46  */
  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         /* check for authenticated data */
 266         if (response->header.ad == 1)
 267                 rrset->rri_flags |= RRSET_VALIDATED;
 268
 269         /* copy name from answer section */
 270         rrset->rri_name = strdup(response->answer->name);
 271         if (rrset->rri_name == NULL) {
 272                 result = ERRSET_NOMEMORY;
 273                 goto fail;
 274         }
 275
 276         /* count answers */
 277         rrset->rri_nrdatas = count_dns_rr(response->answer, rrset->rri_rdclass,
 278             rrset->rri_rdtype);
 279         rrset->rri_nsigs = count_dns_rr(response->answer, rrset->rri_rdclass,
 280             T_SIG);
 281
 282         /* allocate memory for answers */
 283         rrset->rri_rdatas = calloc(rrset->rri_nrdatas,
 284             sizeof(struct rdatainfo));
 285         if (rrset->rri_rdatas == NULL) {
 286                 result = ERRSET_NOMEMORY;
 287                 goto fail;
 288         }
 289
 290         /* allocate memory for signatures */
 291         rrset->rri_sigs = calloc(rrset->rri_nsigs, sizeof(struct rdatainfo));
 292         if (rrset->rri_sigs == NULL) {
 293                 result = ERRSET_NOMEMORY;
 294                 goto fail;
 295         }
 296
 297         /* copy answers & signatures */
 298         for (rr = response->answer, index_ans = 0, index_sig = 0;
 299             rr; rr = rr->next) {
 300
 301                 rdata = NULL;
 302
 303                 if (rr->class == rrset->rri_rdclass &&
 304                     rr->type  == rrset->rri_rdtype)
 305                         rdata = &rrset->rri_rdatas[index_ans++];
 306
 307                 if (rr->class == rrset->rri_rdclass &&
 308                     rr->type  == T_SIG)
 309                         rdata = &rrset->rri_sigs[index_sig++];
 310
 311                 if (rdata) {
 312                         rdata->rdi_length = rr->size;
 313                         rdata->rdi_data   = malloc(rr->size);
 314
 315                         if (rdata->rdi_data == NULL) {
 316                                 result = ERRSET_NOMEMORY;
 317                                 goto fail;
 318                         }
 319                         memcpy(rdata->rdi_data, rr->rdata, rr->size);
 320                 }
 321         }
 322         free_dns_response(response);
 323
 324         *res = rrset;
 325         return (ERRSET_SUCCESS);
 326
 327 fail:
 328         if (rrset != NULL)
 329                 freerrset(rrset);
 330         if (response != NULL)
 331                 free_dns_response(response);
 332         return (result);
 333 }
 334
 335 void
 336 freerrset(struct rrsetinfo *rrset)
 337 {
 338         u_int16_t i;
 339
 340         if (rrset == NULL)
 341                 return;
 342
 343         if (rrset->rri_rdatas) {
 344                 for (i = 0; i < rrset->rri_nrdatas; i++) {
 345                         if (rrset->rri_rdatas[i].rdi_data == NULL)
 346                                 break;
 347                         free(rrset->rri_rdatas[i].rdi_data);
 348                 }
 349                 free(rrset->rri_rdatas);
 350         }
 351
 352         if (rrset->rri_sigs) {
 353                 for (i = 0; i < rrset->rri_nsigs; i++) {
 354                         if (rrset->rri_sigs[i].rdi_data == NULL)
 355                                 break;
 356                         free(rrset->rri_sigs[i].rdi_data);
 357                 }
 358                 free(rrset->rri_sigs);
 359         }
 360
 361         if (rrset->rri_name)
 362                 free(rrset->rri_name);
 363         free(rrset);
 364 }
 365
 366 /*
 367  * DNS response parsing routines
 368  */
 369 static struct dns_response *
 370 parse_dns_response(const u_char *answer, int size)
 371 {
 372         struct dns_response *resp;
 373         const u_char *cp;
 374
 375         /* allocate memory for the response */
 376         resp = calloc(1, sizeof(*resp));
 377         if (resp == NULL)
 378                 return (NULL);
 379
 380         /* initialize current pointer */
 381         cp = answer;
 382
 383         /* copy header */
 384         memcpy(&resp->header, cp, HFIXEDSZ);
 385         cp += HFIXEDSZ;
 386
 387         /* fix header byte order */
 388         resp->header.qdcount = ntohs(resp->header.qdcount);
 389         resp->header.ancount = ntohs(resp->header.ancount);
 390         resp->header.nscount = ntohs(resp->header.nscount);
 391         resp->header.arcount = ntohs(resp->header.arcount);
 392
 393         /* there must be at least one query */
 394         if (resp->header.qdcount < 1) {
 395                 free_dns_response(resp);
 396                 return (NULL);
 397         }
 398
 399         /* parse query section */
 400         resp->query = parse_dns_qsection(answer, size, &cp,
 401             resp->header.qdcount);
 402         if (resp->header.qdcount && resp->query == NULL) {
 403                 free_dns_response(resp);
 404                 return (NULL);
 405         }
 406
 407         /* parse answer section */
 408         resp->answer = parse_dns_rrsection(answer, size, &cp,
 409             resp->header.ancount);
 410         if (resp->header.ancount && resp->answer == NULL) {
 411                 free_dns_response(resp);
 412                 return (NULL);
 413         }
 414
 415         /* parse authority section */
 416         resp->authority = parse_dns_rrsection(answer, size, &cp,
 417             resp->header.nscount);
 418         if (resp->header.nscount && resp->authority == NULL) {
 419                 free_dns_response(resp);
 420                 return (NULL);
 421         }
 422
 423         /* parse additional section */
 424         resp->additional = parse_dns_rrsection(answer, size, &cp,
 425             resp->header.arcount);
 426         if (resp->header.arcount && resp->additional == NULL) {
 427                 free_dns_response(resp);
 428                 return (NULL);
 429         }
 430
 431         return (resp);
 432 }
 433
 434 static struct dns_query *
 435 parse_dns_qsection(const u_char *answer, int size, const u_char **cp, int count)
 436 {
 437         struct dns_query *head, *curr, *prev;
 438         int i, length;
 439         char name[MAXDNAME];
 440
 441         for (i = 1, head = NULL, prev = NULL; i <= count; i++, prev = curr) {
 442
 443                 /* allocate and initialize struct */
 444                 curr = calloc(1, sizeof(struct dns_query));
 445                 if (curr == NULL) {
 446                         free_dns_query(head);
 447                         return (NULL);
 448                 }
 449                 if (head == NULL)
 450                         head = curr;
 451                 if (prev != NULL)
 452                         prev->next = curr;
 453
 454                 /* name */
 455                 length = dn_expand(answer, answer + size, *cp, name,
 456                     sizeof(name));
 457                 if (length < 0) {
 458                         free_dns_query(head);
 459                         return (NULL);
 460                 }
 461                 curr->name = strdup(name);
 462                 if (curr->name == NULL) {
 463                         free_dns_query(head);
 464                         return (NULL);
 465                 }
 466                 *cp += length;
 467
 468                 /* type */
 469                 curr->type = _getshort(*cp);
 470                 *cp += INT16SZ;
 471
 472                 /* class */
 473                 curr->class = _getshort(*cp);
 474                 *cp += INT16SZ;
 475         }
 476
 477         return (head);
 478 }
 479
 480 static struct dns_rr *
 481 parse_dns_rrsection(const u_char *answer, int size, const u_char **cp,
 482     int count)
 483 {
 484         struct dns_rr *head, *curr, *prev;
 485         int i, length;
 486         char name[MAXDNAME];
 487
 488         for (i = 1, head = NULL, prev = NULL; i <= count; i++, prev = curr) {
 489
 490                 /* allocate and initialize struct */
 491                 curr = calloc(1, sizeof(struct dns_rr));
 492                 if (curr == NULL) {
 493                         free_dns_rr(head);
 494                         return (NULL);
 495                 }
 496                 if (head == NULL)
 497                         head = curr;
 498                 if (prev != NULL)
 499                         prev->next = curr;
 500
 501                 /* name */
 502                 length = dn_expand(answer, answer + size, *cp, name,
 503                     sizeof(name));
 504                 if (length < 0) {
 505                         free_dns_rr(head);
 506                         return (NULL);
 507                 }
 508                 curr->name = strdup(name);
 509                 if (curr->name == NULL) {
 510                         free_dns_rr(head);
 511                         return (NULL);
 512                 }
 513                 *cp += length;
 514
 515                 /* type */
 516                 curr->type = _getshort(*cp);
 517                 *cp += INT16SZ;
 518
 519                 /* class */
 520                 curr->class = _getshort(*cp);
 521                 *cp += INT16SZ;
 522
 523                 /* ttl */
 524                 curr->ttl = _getlong(*cp);
 525                 *cp += INT32SZ;
 526
 527                 /* rdata size */
 528                 curr->size = _getshort(*cp);
 529                 *cp += INT16SZ;
 530
 531                 /* rdata itself */
 532                 curr->rdata = malloc(curr->size);
 533                 if (curr->rdata == NULL) {
 534                         free_dns_rr(head);
 535                         return (NULL);
 536                 }
 537                 memcpy(curr->rdata, *cp, curr->size);
 538                 *cp += curr->size;
 539         }
 540
 541         return (head);
 542 }
 543
 544 static void
 545 free_dns_query(struct dns_query *p)
 546 {
 547         if (p == NULL)
 548                 return;
 549
 550         if (p->name)
 551                 free(p->name);
 552         free_dns_query(p->next);
 553         free(p);
 554 }
 555
 556 static void
 557 free_dns_rr(struct dns_rr *p)
 558 {
 559         if (p == NULL)
 560                 return;
 561
 562         if (p->name)
 563                 free(p->name);
 564         if (p->rdata)
 565                 free(p->rdata);
 566         free_dns_rr(p->next);
 567         free(p);
 568 }
 569
 570 static void
 571 free_dns_response(struct dns_response *p)
 572 {
 573         if (p == NULL)
 574                 return;
 575
 576         free_dns_query(p->query);
 577         free_dns_rr(p->answer);
 578         free_dns_rr(p->authority);
 579         free_dns_rr(p->additional);
 580         free(p);
 581 }
 582
 583 static int
 584 count_dns_rr(struct dns_rr *p, u_int16_t class, u_int16_t type)
 585 {
 586         int n = 0;
 587
 588         while(p) {
 589                 if (p->class == class && p->type == type)
 590                         n++;
 591                 p = p->next;
 592         }
 593
 594         return (n);
 595 }
 596
 597 #endif /* !defined(HAVE_GETRRSETBYNAME) */