openbsd-compat/getrrsetbyname.c

   1 /* OPENBSD ORIGINAL: lib/libc/net/getrrsetbyname.c */
   2
   3 /* $OpenBSD: getrrsetbyname.c,v 1.7 2003/03/07 07:34:14 itojun 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 #define ANSWER_BUFFER_SIZE 1024*64
  55
  56 #if defined(HAVE_DECL_H_ERRNO) && !HAVE_DECL_H_ERRNO
  57 extern int h_errno;
  58 #endif
  59
  60 struct dns_query {
  61         char                    *name;
  62         u_int16_t               type;
  63         u_int16_t               class;
  64         struct dns_query        *next;
  65 };
  66
  67 struct dns_rr {
  68         char                    *name;
  69         u_int16_t               type;
  70         u_int16_t               class;
  71         u_int16_t               ttl;
  72         u_int16_t               size;
  73         void                    *rdata;
  74         struct dns_rr           *next;
  75 };
  76
  77 struct dns_response {
  78         HEADER                  header;
  79         struct dns_query        *query;
  80         struct dns_rr           *answer;
  81         struct dns_rr           *authority;
  82         struct dns_rr           *additional;
  83 };
  84
  85 static struct dns_response *parse_dns_response(const u_char *, int);
  86 static struct dns_query *parse_dns_qsection(const u_char *, int,
  87     const u_char **, int);
  88 static struct dns_rr *parse_dns_rrsection(const u_char *, int, const u_char **,
  89     int);
  90
  91 static void free_dns_query(struct dns_query *);
  92 static void free_dns_rr(struct dns_rr *);
  93 static void free_dns_response(struct dns_response *);
  94
  95 static int count_dns_rr(struct dns_rr *, u_int16_t, u_int16_t);
  96
  97 /*
  98  * Inline versions of get/put short/long.  Pointer is advanced.
  99  *
 100  * These macros demonstrate the property of C whereby it can be
 101  * portable or it can be elegant but rarely both.
 102  */
 103
 104 #ifndef INT32SZ
 105 # define INT32SZ        4
 106 #endif
 107 #ifndef INT16SZ
 108 # define INT16SZ        2
 109 #endif
 110
 111 #ifndef GETSHORT
 112 #define GETSHORT(s, cp) { \
 113         register u_char *t_cp = (u_char *)(cp); \
 114         (s) = ((u_int16_t)t_cp[0] << 8) \
 115             | ((u_int16_t)t_cp[1]) \
 116             ; \
 117         (cp) += INT16SZ; \
 118 }
 119 #endif
 120
 121 #ifndef GETLONG
 122 #define GETLONG(l, cp) { \
 123         register u_char *t_cp = (u_char *)(cp); \
 124         (l) = ((u_int32_t)t_cp[0] << 24) \
 125             | ((u_int32_t)t_cp[1] << 16) \
 126             | ((u_int32_t)t_cp[2] << 8) \
 127             | ((u_int32_t)t_cp[3]) \
 128             ; \
 129         (cp) += INT32SZ; \
 130 }
 131 #endif
 132
 133 /*
 134  * Routines to insert/extract short/long's.
 135  */
 136
 137 #ifndef HAVE__GETSHORT
 138 static u_int16_t
 139 _getshort(msgp)
 140         register const u_char *msgp;
 141 {
 142         register u_int16_t u;
 143
 144         GETSHORT(u, msgp);
 145         return (u);
 146 }
 147 #endif
 148
 149 #ifndef HAVE__GETLONG
 150 static u_int32_t
 151 _getlong(msgp)
 152         register const u_char *msgp;
 153 {
 154         register u_int32_t u;
 155
 156         GETLONG(u, msgp);
 157         return (u);
 158 }
 159 #endif
 160
 161 int
 162 getrrsetbyname(const char *hostname, unsigned int rdclass,
 163     unsigned int rdtype, unsigned int flags,
 164     struct rrsetinfo **res)
 165 {
 166         int result;
 167         struct rrsetinfo *rrset = NULL;
 168         struct dns_response *response;
 169         struct dns_rr *rr;
 170         struct rdatainfo *rdata;
 171         int length;
 172         unsigned int index_ans, index_sig;
 173         u_char answer[ANSWER_BUFFER_SIZE];
 174
 175         /* check for invalid class and type */
 176         if (rdclass > 0xffff || rdtype > 0xffff) {
 177                 result = ERRSET_INVAL;
 178                 goto fail;
 179         }
 180
 181         /* don't allow queries of class or type ANY */
 182         if (rdclass == 0xff || rdtype == 0xff) {
 183                 result = ERRSET_INVAL;
 184                 goto fail;
 185         }
 186
 187         /* don't allow flags yet, unimplemented */
 188         if (flags) {
 189                 result = ERRSET_INVAL;
 190                 goto fail;
 191         }
 192
 193         /* initialize resolver */
 194         if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
 195                 result = ERRSET_FAIL;
 196                 goto fail;
 197         }
 198
 199 #ifdef DEBUG
 200         _res.options |= RES_DEBUG;
 201 #endif /* DEBUG */
 202
 203 #ifdef RES_USE_DNSSEC
 204         /* turn on DNSSEC if EDNS0 is configured */
 205         if (_res.options & RES_USE_EDNS0)
 206                 _res.options |= RES_USE_DNSSEC;
 207 #endif /* RES_USE_DNSEC */
 208
 209         /* make query */
 210         length = res_query(hostname, (signed int) rdclass, (signed int) rdtype,
 211             answer, sizeof(answer));
 212         if (length < 0) {
 213                 switch(h_errno) {
 214                 case HOST_NOT_FOUND:
 215                         result = ERRSET_NONAME;
 216                         goto fail;
 217                 case NO_DATA:
 218                         result = ERRSET_NODATA;
 219                         goto fail;
 220                 default:
 221                         result = ERRSET_FAIL;
 222                         goto fail;
 223                 }
 224         }
 225
 226         /* parse result */
 227         response = parse_dns_response(answer, length);
 228         if (response == NULL) {
 229                 result = ERRSET_FAIL;
 230                 goto fail;
 231         }
 232
 233         if (response->header.qdcount != 1) {
 234                 result = ERRSET_FAIL;
 235                 goto fail;
 236         }
 237
 238         /* initialize rrset */
 239         rrset = calloc(1, sizeof(struct rrsetinfo));
 240         if (rrset == NULL) {
 241                 result = ERRSET_NOMEMORY;
 242                 goto fail;
 243         }
 244         rrset->rri_rdclass = response->query->class;
 245         rrset->rri_rdtype = response->query->type;
 246         rrset->rri_ttl = response->answer->ttl;
 247         rrset->rri_nrdatas = response->header.ancount;
 248
 249 #ifdef HAVE_HEADER_AD
 250         /* check for authenticated data */
 251         if (response->header.ad == 1)
 252                 rrset->rri_flags |= RRSET_VALIDATED;
 253 #endif
 254
 255         /* copy name from answer section */
 256         length = strlen(response->answer->name);
 257         rrset->rri_name = malloc(length + 1);
 258         if (rrset->rri_name == NULL) {
 259                 result = ERRSET_NOMEMORY;
 260                 goto fail;
 261         }
 262         strlcpy(rrset->rri_name, response->answer->name, length + 1);
 263
 264         /* count answers */
 265         rrset->rri_nrdatas = count_dns_rr(response->answer, rrset->rri_rdclass,
 266             rrset->rri_rdtype);
 267         rrset->rri_nsigs = count_dns_rr(response->answer, rrset->rri_rdclass,
 268             T_SIG);
 269
 270         /* allocate memory for answers */
 271         rrset->rri_rdatas = calloc(rrset->rri_nrdatas,
 272             sizeof(struct rdatainfo));
 273         if (rrset->rri_rdatas == NULL) {
 274                 result = ERRSET_NOMEMORY;
 275                 goto fail;
 276         }
 277
 278         /* allocate memory for signatures */
 279         rrset->rri_sigs = calloc(rrset->rri_nsigs, sizeof(struct rdatainfo));
 280         if (rrset->rri_nsigs > 0 && rrset->rri_sigs == NULL) {
 281                 result = ERRSET_NOMEMORY;
 282                 goto fail;
 283         }
 284
 285         /* copy answers & signatures */
 286         for (rr = response->answer, index_ans = 0, index_sig = 0;
 287             rr; rr = rr->next) {
 288
 289                 rdata = NULL;
 290
 291                 if (rr->class == rrset->rri_rdclass &&
 292                     rr->type  == rrset->rri_rdtype)
 293                         rdata = &rrset->rri_rdatas[index_ans++];
 294
 295                 if (rr->class == rrset->rri_rdclass &&
 296                     rr->type  == T_SIG)
 297                         rdata = &rrset->rri_sigs[index_sig++];
 298
 299                 if (rdata) {
 300                         rdata->rdi_length = rr->size;
 301                         rdata->rdi_data   = malloc(rr->size);
 302
 303                         if (rdata->rdi_data == NULL) {
 304                                 result = ERRSET_NOMEMORY;
 305                                 goto fail;
 306                         }
 307                         memcpy(rdata->rdi_data, rr->rdata, rr->size);
 308                 }
 309         }
 310
 311         *res = rrset;
 312         return (ERRSET_SUCCESS);
 313
 314 fail:
 315         if (rrset != NULL)
 316                 freerrset(rrset);
 317         return (result);
 318 }
 319
 320 void
 321 freerrset(struct rrsetinfo *rrset)
 322 {
 323         u_int16_t i;
 324
 325         if (rrset == NULL)
 326                 return;
 327
 328         if (rrset->rri_rdatas) {
 329                 for (i = 0; i < rrset->rri_nrdatas; i++) {
 330                         if (rrset->rri_rdatas[i].rdi_data == NULL)
 331                                 break;
 332                         free(rrset->rri_rdatas[i].rdi_data);
 333                 }
 334                 free(rrset->rri_rdatas);
 335         }
 336
 337         if (rrset->rri_sigs) {
 338                 for (i = 0; i < rrset->rri_nsigs; i++) {
 339                         if (rrset->rri_sigs[i].rdi_data == NULL)
 340                                 break;
 341                         free(rrset->rri_sigs[i].rdi_data);
 342                 }
 343                 free(rrset->rri_sigs);
 344         }
 345
 346         if (rrset->rri_name)
 347                 free(rrset->rri_name);
 348         free(rrset);
 349 }
 350
 351 /*
 352  * DNS response parsing routines
 353  */
 354 static struct dns_response *
 355 parse_dns_response(const u_char *answer, int size)
 356 {
 357         struct dns_response *resp;
 358         const u_char *cp;
 359
 360         /* allocate memory for the response */
 361         resp = calloc(1, sizeof(*resp));
 362         if (resp == NULL)
 363                 return (NULL);
 364
 365         /* initialize current pointer */
 366         cp = answer;
 367
 368         /* copy header */
 369         memcpy(&resp->header, cp, HFIXEDSZ);
 370         cp += HFIXEDSZ;
 371
 372         /* fix header byte order */
 373         resp->header.qdcount = ntohs(resp->header.qdcount);
 374         resp->header.ancount = ntohs(resp->header.ancount);
 375         resp->header.nscount = ntohs(resp->header.nscount);
 376         resp->header.arcount = ntohs(resp->header.arcount);
 377
 378         /* there must be at least one query */
 379         if (resp->header.qdcount < 1) {
 380                 free_dns_response(resp);
 381                 return (NULL);
 382         }
 383
 384         /* parse query section */
 385         resp->query = parse_dns_qsection(answer, size, &cp,
 386             resp->header.qdcount);
 387         if (resp->header.qdcount && resp->query == NULL) {
 388                 free_dns_response(resp);
 389                 return (NULL);
 390         }
 391
 392         /* parse answer section */
 393         resp->answer = parse_dns_rrsection(answer, size, &cp,
 394             resp->header.ancount);
 395         if (resp->header.ancount && resp->answer == NULL) {
 396                 free_dns_response(resp);
 397                 return (NULL);
 398         }
 399
 400         /* parse authority section */
 401         resp->authority = parse_dns_rrsection(answer, size, &cp,
 402             resp->header.nscount);
 403         if (resp->header.nscount && resp->authority == NULL) {
 404                 free_dns_response(resp);
 405                 return (NULL);
 406         }
 407
 408         /* parse additional section */
 409         resp->additional = parse_dns_rrsection(answer, size, &cp,
 410             resp->header.arcount);
 411         if (resp->header.arcount && resp->additional == NULL) {
 412                 free_dns_response(resp);
 413                 return (NULL);
 414         }
 415
 416         return (resp);
 417 }
 418
 419 static struct dns_query *
 420 parse_dns_qsection(const u_char *answer, int size, const u_char **cp, int count)
 421 {
 422         struct dns_query *head, *curr, *prev;
 423         int i, length;
 424         char name[MAXDNAME];
 425
 426         for (i = 1, head = NULL, prev = NULL; i <= count; i++, prev = curr) {
 427
 428                 /* allocate and initialize struct */
 429                 curr = calloc(1, sizeof(struct dns_query));
 430                 if (curr == NULL) {
 431                         free_dns_query(head);
 432                         return (NULL);
 433                 }
 434                 if (head == NULL)
 435                         head = curr;
 436                 if (prev != NULL)
 437                         prev->next = curr;
 438
 439                 /* name */
 440                 length = dn_expand(answer, answer + size, *cp, name,
 441                     sizeof(name));
 442                 if (length < 0) {
 443                         free_dns_query(head);
 444                         return (NULL);
 445                 }
 446                 curr->name = strdup(name);
 447                 if (curr->name == NULL) {
 448                         free_dns_query(head);
 449                         return (NULL);
 450                 }
 451                 *cp += length;
 452
 453                 /* type */
 454                 curr->type = _getshort(*cp);
 455                 *cp += INT16SZ;
 456
 457                 /* class */
 458                 curr->class = _getshort(*cp);
 459                 *cp += INT16SZ;
 460         }
 461
 462         return (head);
 463 }
 464
 465 static struct dns_rr *
 466 parse_dns_rrsection(const u_char *answer, int size, const u_char **cp, int count)
 467 {
 468         struct dns_rr *head, *curr, *prev;
 469         int i, length;
 470         char name[MAXDNAME];
 471
 472         for (i = 1, head = NULL, prev = NULL; i <= count; i++, prev = curr) {
 473
 474                 /* allocate and initialize struct */
 475                 curr = calloc(1, sizeof(struct dns_rr));
 476                 if (curr == NULL) {
 477                         free_dns_rr(head);
 478                         return (NULL);
 479                 }
 480                 if (head == NULL)
 481                         head = curr;
 482                 if (prev != NULL)
 483                         prev->next = curr;
 484
 485                 /* name */
 486                 length = dn_expand(answer, answer + size, *cp, name,
 487                     sizeof(name));
 488                 if (length < 0) {
 489                         free_dns_rr(head);
 490                         return (NULL);
 491                 }
 492                 curr->name = strdup(name);
 493                 if (curr->name == NULL) {
 494                         free_dns_rr(head);
 495                         return (NULL);
 496                 }
 497                 *cp += length;
 498
 499                 /* type */
 500                 curr->type = _getshort(*cp);
 501                 *cp += INT16SZ;
 502
 503                 /* class */
 504                 curr->class = _getshort(*cp);
 505                 *cp += INT16SZ;
 506
 507                 /* ttl */
 508                 curr->ttl = _getlong(*cp);
 509                 *cp += INT32SZ;
 510
 511                 /* rdata size */
 512                 curr->size = _getshort(*cp);
 513                 *cp += INT16SZ;
 514
 515                 /* rdata itself */
 516                 curr->rdata = malloc(curr->size);
 517                 if (curr->rdata == NULL) {
 518                         free_dns_rr(head);
 519                         return (NULL);
 520                 }
 521                 memcpy(curr->rdata, *cp, curr->size);
 522                 *cp += curr->size;
 523         }
 524
 525         return (head);
 526 }
 527
 528 static void
 529 free_dns_query(struct dns_query *p)
 530 {
 531         if (p == NULL)
 532                 return;
 533
 534         if (p->name)
 535                 free(p->name);
 536         free_dns_query(p->next);
 537         free(p);
 538 }
 539
 540 static void
 541 free_dns_rr(struct dns_rr *p)
 542 {
 543         if (p == NULL)
 544                 return;
 545
 546         if (p->name)
 547                 free(p->name);
 548         if (p->rdata)
 549                 free(p->rdata);
 550         free_dns_rr(p->next);
 551         free(p);
 552 }
 553
 554 static void
 555 free_dns_response(struct dns_response *p)
 556 {
 557         if (p == NULL)
 558                 return;
 559
 560         free_dns_query(p->query);
 561         free_dns_rr(p->answer);
 562         free_dns_rr(p->authority);
 563         free_dns_rr(p->additional);
 564         free(p);
 565 }
 566
 567 static int
 568 count_dns_rr(struct dns_rr *p, u_int16_t class, u_int16_t type)
 569 {
 570         int n = 0;
 571
 572         while(p) {
 573                 if (p->class == class && p->type == type)
 574                         n++;
 575                 p = p->next;
 576         }
 577
 578         return (n);
 579 }
 580
 581 #endif /* !defined(HAVE_GETRRSETBYNAME) */