lib/addns/dnsrecord.c

   1 /*
   2   Linux DNS client library implementation
   3   Copyright (C) 2006 Krishna Ganugapati <krishnag@centeris.com>
   4   Copyright (C) 2006 Gerald Carter <jerry@samba.org>
   5
   6      ** NOTE! The following LGPL license applies to the libaddns
   7      ** library. This does NOT imply that all of Samba is released
   8      ** under the LGPL
   9
  10   This library is free software; you can redistribute it and/or
  11   modify it under the terms of the GNU Lesser General Public
  12   License as published by the Free Software Foundation; either
  13   version 2.1 of the License, or (at your option) any later version.
  14
  15   This library is distributed in the hope that it will be useful,
  16   but WITHOUT ANY WARRANTY; without even the implied warranty of
  17   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18   Lesser General Public License for more details.
  19
  20   You should have received a copy of the GNU Lesser General Public
  21   License along with this library; if not, see <http://www.gnu.org/licenses/>.
  22 */
  23
  24 #include "dns.h"
  25
  26 DNS_ERROR dns_create_query( TALLOC_CTX *mem_ctx, const char *name,
  27                             uint16_t q_type, uint16_t q_class,
  28                             struct dns_request **preq )
  29 {
  30         struct dns_request *req = NULL;
  31         struct dns_question *q = NULL;
  32         DNS_ERROR err;
  33
  34         if (!(req = talloc_zero(mem_ctx, struct dns_request)) ||
  35             !(req->questions = talloc_array(req, struct dns_question *, 1)) ||
  36             !(req->questions[0] = talloc(req->questions,
  37                                          struct dns_question))) {
  38                 TALLOC_FREE(req);
  39                 return ERROR_DNS_NO_MEMORY;
  40         }
  41
  42         req->id = random();
  43
  44         req->num_questions = 1;
  45         q = req->questions[0];
  46
  47         err = dns_domain_name_from_string(q, name, &q->name);
  48         if (!ERR_DNS_IS_OK(err)) {
  49                 TALLOC_FREE(req);
  50                 return err;
  51         }
  52
  53         q->q_type = q_type;
  54         q->q_class = q_class;
  55
  56         *preq = req;
  57         return ERROR_DNS_SUCCESS;
  58 }
  59
  60 DNS_ERROR dns_create_update( TALLOC_CTX *mem_ctx, const char *name,
  61                              struct dns_update_request **preq )
  62 {
  63         struct dns_update_request *req = NULL;
  64         struct dns_zone *z = NULL;
  65         DNS_ERROR err;
  66
  67         if (!(req = talloc_zero(mem_ctx, struct dns_update_request)) ||
  68             !(req->zones = talloc_array(req, struct dns_zone *, 1)) ||
  69             !(req->zones[0] = talloc(req->zones, struct dns_zone))) {
  70                 TALLOC_FREE(req);
  71                 return ERROR_DNS_NO_MEMORY;
  72         }
  73
  74         req->id = random();
  75         req->flags = 0x2800;    /* Dynamic update */
  76
  77         req->num_zones = 1;
  78         z = req->zones[0];
  79
  80         err = dns_domain_name_from_string(z, name, &z->name);
  81         if (!ERR_DNS_IS_OK(err)) {
  82                 TALLOC_FREE(req);
  83                 return err;
  84         }
  85
  86         z->z_type = QTYPE_SOA;
  87         z->z_class = DNS_CLASS_IN;
  88
  89         *preq = req;
  90         return ERROR_DNS_SUCCESS;
  91 }
  92
  93 DNS_ERROR dns_create_rrec(TALLOC_CTX *mem_ctx, const char *name,
  94                           uint16_t type, uint16_t r_class, uint32_t ttl,
  95                           uint16_t data_length, uint8_t *data,
  96                           struct dns_rrec **prec)
  97 {
  98         struct dns_rrec *rec = NULL;
  99         DNS_ERROR err;
 100
 101         if (!(rec = talloc(mem_ctx, struct dns_rrec))) {
 102                 return ERROR_DNS_NO_MEMORY;
 103         }
 104
 105         err = dns_domain_name_from_string(rec, name, &rec->name);
 106         if (!(ERR_DNS_IS_OK(err))) {
 107                 TALLOC_FREE(rec);
 108                 return err;
 109         }
 110
 111         rec->type = type;
 112         rec->r_class = r_class;
 113         rec->ttl = ttl;
 114         rec->data_length = data_length;
 115         rec->data = talloc_move(rec, &data);
 116
 117         *prec = rec;
 118         return ERROR_DNS_SUCCESS;
 119 }
 120
 121 DNS_ERROR dns_create_a_record(TALLOC_CTX *mem_ctx, const char *host,
 122                               uint32_t ttl, const struct sockaddr_storage *pss,
 123                               struct dns_rrec **prec)
 124 {
 125         uint8_t *data;
 126         DNS_ERROR err;
 127         struct in_addr ip;
 128
 129         if (pss->ss_family != AF_INET) {
 130                 return ERROR_DNS_INVALID_PARAMETER;
 131         }
 132
 133         ip = ((const struct sockaddr_in *)pss)->sin_addr;
 134         if (!(data = (uint8_t *)talloc_memdup(mem_ctx, (const void *)&ip.s_addr,
 135                                             sizeof(ip.s_addr)))) {
 136                 return ERROR_DNS_NO_MEMORY;
 137         }
 138
 139         err = dns_create_rrec(mem_ctx, host, QTYPE_A, DNS_CLASS_IN, ttl,
 140                               sizeof(ip.s_addr), data, prec);
 141
 142         if (!ERR_DNS_IS_OK(err)) {
 143                 TALLOC_FREE(data);
 144         }
 145
 146         return err;
 147 }
 148
 149 DNS_ERROR dns_create_aaaa_record(TALLOC_CTX *mem_ctx, const char *host,
 150                                  uint32_t ttl, const struct sockaddr_storage *pss,
 151                                  struct dns_rrec **prec)
 152 {
 153 #ifdef HAVE_IPV6
 154         uint8_t *data;
 155         DNS_ERROR err;
 156         struct in6_addr ip6;
 157
 158         if (pss->ss_family != AF_INET6) {
 159                 return ERROR_DNS_INVALID_PARAMETER;
 160         }
 161
 162         ip6 = ((const struct sockaddr_in6 *)pss)->sin6_addr;
 163         if (!(data = (uint8_t *)talloc_memdup(mem_ctx, (const void *)&ip6.s6_addr,
 164                                             sizeof(ip6.s6_addr)))) {
 165                 return ERROR_DNS_NO_MEMORY;
 166         }
 167
 168         err = dns_create_rrec(mem_ctx, host, QTYPE_AAAA, DNS_CLASS_IN, ttl,
 169                               sizeof(ip6.s6_addr), data, prec);
 170
 171         if (!ERR_DNS_IS_OK(err)) {
 172                 TALLOC_FREE(data);
 173         }
 174
 175         return err;
 176 #else
 177         return ERROR_DNS_INVALID_PARAMETER;
 178 #endif
 179 }
 180
 181 DNS_ERROR dns_create_name_in_use_record(TALLOC_CTX *mem_ctx,
 182                                         const char *name,
 183                                         const struct sockaddr_storage *ss,
 184                                         struct dns_rrec **prec)
 185 {
 186         if (ss != NULL) {
 187                 switch (ss->ss_family) {
 188                 case AF_INET:
 189                         return dns_create_a_record(mem_ctx, name, 0, ss, prec);
 190 #ifdef HAVE_IPV6
 191                 case AF_INET6:
 192                         return dns_create_aaaa_record(mem_ctx, name, 0, ss, prec);
 193 #endif
 194                 default:
 195                         return ERROR_DNS_INVALID_PARAMETER;
 196                 }
 197         }
 198
 199         return dns_create_rrec(mem_ctx, name, QTYPE_ANY, DNS_CLASS_IN, 0, 0,
 200                                NULL, prec);
 201 }
 202
 203 DNS_ERROR dns_create_name_not_in_use_record(TALLOC_CTX *mem_ctx,
 204                                             const char *name, uint32_t type,
 205                                             struct dns_rrec **prec)
 206 {
 207         return dns_create_rrec(mem_ctx, name, type, DNS_CLASS_NONE, 0,
 208                                0, NULL, prec);
 209 }
 210
 211 DNS_ERROR dns_create_delete_record(TALLOC_CTX *mem_ctx, const char *name,
 212                                    uint16_t type, uint16_t r_class,
 213                                    struct dns_rrec **prec)
 214 {
 215         return dns_create_rrec(mem_ctx, name, type, r_class, 0, 0, NULL, prec);
 216 }
 217
 218 DNS_ERROR dns_create_tkey_record(TALLOC_CTX *mem_ctx, const char *keyname,
 219                                  const char *algorithm_name, time_t inception,
 220                                  time_t expiration, uint16_t mode, uint16_t error,
 221                                  uint16_t key_length, const uint8_t *key,
 222                                  struct dns_rrec **prec)
 223 {
 224         struct dns_buffer *buf = NULL;
 225         struct dns_domain_name *algorithm = NULL;
 226         DNS_ERROR err;
 227
 228         if (!(buf = dns_create_buffer(mem_ctx))) {
 229                 return ERROR_DNS_NO_MEMORY;
 230         }
 231
 232         err = dns_domain_name_from_string(buf, algorithm_name, &algorithm);
 233         if (!ERR_DNS_IS_OK(err)) goto error;
 234
 235         dns_marshall_domain_name(buf, algorithm);
 236         dns_marshall_uint32(buf, inception);
 237         dns_marshall_uint32(buf, expiration);
 238         dns_marshall_uint16(buf, mode);
 239         dns_marshall_uint16(buf, error);
 240         dns_marshall_uint16(buf, key_length);
 241         dns_marshall_buffer(buf, key, key_length);
 242         dns_marshall_uint16(buf, 0); /* Other Size */
 243
 244         if (!ERR_DNS_IS_OK(buf->error)) {
 245                 err = buf->error;
 246                 goto error;
 247         }
 248
 249         err = dns_create_rrec(mem_ctx, keyname, QTYPE_TKEY, DNS_CLASS_ANY, 0,
 250                               buf->offset, buf->data, prec);
 251
 252  error:
 253         TALLOC_FREE(buf);
 254         return err;
 255 }
 256
 257 DNS_ERROR dns_unmarshall_tkey_record(TALLOC_CTX *mem_ctx, struct dns_rrec *rec,
 258                                      struct dns_tkey_record **ptkey)
 259 {
 260         struct dns_tkey_record *tkey;
 261         struct dns_buffer buf;
 262         uint32_t tmp_inception, tmp_expiration;
 263
 264         if (!(tkey = talloc(mem_ctx, struct dns_tkey_record))) {
 265                 return ERROR_DNS_NO_MEMORY;
 266         }
 267
 268         buf.data = rec->data;
 269         buf.size = rec->data_length;
 270         buf.offset = 0;
 271         buf.error = ERROR_DNS_SUCCESS;
 272
 273         dns_unmarshall_domain_name(tkey, &buf, &tkey->algorithm);
 274         dns_unmarshall_uint32(&buf, &tmp_inception);
 275         dns_unmarshall_uint32(&buf, &tmp_expiration);
 276         dns_unmarshall_uint16(&buf, &tkey->mode);
 277         dns_unmarshall_uint16(&buf, &tkey->error);
 278         dns_unmarshall_uint16(&buf, &tkey->key_length);
 279
 280         if (!ERR_DNS_IS_OK(buf.error)) goto error;
 281
 282         if (tkey->key_length) {
 283                 if (!(tkey->key = talloc_array(tkey, uint8_t, tkey->key_length))) {
 284                         buf.error = ERROR_DNS_NO_MEMORY;
 285                         goto error;
 286                 }
 287         } else {
 288                 tkey->key = NULL;
 289         }
 290
 291         dns_unmarshall_buffer(&buf, tkey->key, tkey->key_length);
 292         if (!ERR_DNS_IS_OK(buf.error)) goto error;
 293
 294         tkey->inception = (time_t)tmp_inception;
 295         tkey->expiration = (time_t)tmp_expiration;
 296
 297         *ptkey = tkey;
 298         return ERROR_DNS_SUCCESS;
 299
 300  error:
 301         TALLOC_FREE(tkey);
 302         return buf.error;
 303 }
 304
 305 DNS_ERROR dns_create_tsig_record(TALLOC_CTX *mem_ctx, const char *keyname,
 306                                  const char *algorithm_name,
 307                                  time_t time_signed, uint16_t fudge,
 308                                  uint16_t mac_length, const uint8_t *mac,
 309                                  uint16_t original_id, uint16_t error,
 310                                  struct dns_rrec **prec)
 311 {
 312         struct dns_buffer *buf = NULL;
 313         struct dns_domain_name *algorithm = NULL;
 314         DNS_ERROR err;
 315
 316         if (!(buf = dns_create_buffer(mem_ctx))) {
 317                 return ERROR_DNS_NO_MEMORY;
 318         }
 319
 320         err = dns_domain_name_from_string(buf, algorithm_name, &algorithm);
 321         if (!ERR_DNS_IS_OK(err)) goto error;
 322
 323         dns_marshall_domain_name(buf, algorithm);
 324         dns_marshall_uint16(buf, 0); /* time prefix */
 325         dns_marshall_uint32(buf, time_signed);
 326         dns_marshall_uint16(buf, fudge);
 327         dns_marshall_uint16(buf, mac_length);
 328         dns_marshall_buffer(buf, mac, mac_length);
 329         dns_marshall_uint16(buf, original_id);
 330         dns_marshall_uint16(buf, error);
 331         dns_marshall_uint16(buf, 0); /* Other Size */
 332
 333         if (!ERR_DNS_IS_OK(buf->error)) {
 334                 err = buf->error;
 335                 goto error;
 336         }
 337
 338         err = dns_create_rrec(mem_ctx, keyname, QTYPE_TSIG, DNS_CLASS_ANY, 0,
 339                               buf->offset, buf->data, prec);
 340
 341  error:
 342         TALLOC_FREE(buf);
 343         return err;
 344 }
 345
 346 DNS_ERROR dns_add_rrec(TALLOC_CTX *mem_ctx, struct dns_rrec *rec,
 347                        uint16_t *num_records, struct dns_rrec ***records)
 348 {
 349         struct dns_rrec **new_records;
 350
 351         if (!(new_records = talloc_realloc(mem_ctx, *records,
 352                                                  struct dns_rrec *,
 353                                                  (*num_records)+1))) {
 354                 return ERROR_DNS_NO_MEMORY;
 355         }
 356
 357         new_records[*num_records] = talloc_move(new_records, &rec);
 358
 359         *num_records += 1;
 360         *records = new_records;
 361         return ERROR_DNS_SUCCESS;
 362 }
 363
 364 /*
 365  * Create a request that probes a server whether the list of IP addresses
 366  * provides meets our expectations
 367  */
 368
 369 DNS_ERROR dns_create_probe(TALLOC_CTX *mem_ctx, const char *zone,
 370                            const char *host, int num_ips,
 371                            const struct sockaddr_storage *sslist,
 372                            struct dns_update_request **preq)
 373 {
 374         struct dns_update_request *req = NULL;
 375         struct dns_rrec *rec = NULL;
 376         DNS_ERROR err;
 377         uint16_t i;
 378
 379         err = dns_create_update(mem_ctx, zone, &req);
 380         if (!ERR_DNS_IS_OK(err)) return err;
 381
 382         err = dns_create_name_not_in_use_record(req, host, QTYPE_CNAME, &rec);
 383         if (!ERR_DNS_IS_OK(err)) goto error;
 384
 385         err = dns_add_rrec(req, rec, &req->num_preqs, &req->preqs);
 386         if (!ERR_DNS_IS_OK(err)) goto error;
 387
 388         for (i=0; i<num_ips; i++) {
 389                 err = dns_create_name_in_use_record(req, host,
 390                                                     &sslist[i], &rec);
 391                 if (!ERR_DNS_IS_OK(err)) goto error;
 392
 393                 err = dns_add_rrec(req, rec, &req->num_preqs, &req->preqs);
 394                 if (!ERR_DNS_IS_OK(err)) goto error;
 395         }
 396
 397         *preq = req;
 398         return ERROR_DNS_SUCCESS;
 399
 400  error:
 401         TALLOC_FREE(req);
 402         return err;
 403 }
 404
 405 DNS_ERROR dns_create_update_request(TALLOC_CTX *mem_ctx,
 406                                     const char *domainname,
 407                                     const char *hostname,
 408                                     const struct sockaddr_storage *ss_addrs,
 409                                     size_t num_addrs,
 410                                     struct dns_update_request **preq)
 411 {
 412         struct dns_update_request *req = NULL;
 413         struct dns_rrec *rec = NULL;
 414         DNS_ERROR err;
 415         size_t i;
 416
 417         err = dns_create_update(mem_ctx, domainname, &req);
 418         if (!ERR_DNS_IS_OK(err)) return err;
 419
 420         /*
 421          * Use the same prereq as WinXP -- No CNAME records for this host.
 422          */
 423
 424         err = dns_create_rrec(req, hostname, QTYPE_CNAME, DNS_CLASS_NONE,
 425                               0, 0, NULL, &rec);
 426         if (!ERR_DNS_IS_OK(err)) goto error;
 427
 428         err = dns_add_rrec(req, rec, &req->num_preqs, &req->preqs);
 429         if (!ERR_DNS_IS_OK(err)) goto error;
 430
 431         /*
 432          * Delete any existing A records
 433          */
 434
 435         err = dns_create_delete_record(req, hostname, QTYPE_A, DNS_CLASS_ANY,
 436                                        &rec);
 437         if (!ERR_DNS_IS_OK(err)) goto error;
 438
 439         err = dns_add_rrec(req, rec, &req->num_updates, &req->updates);
 440         if (!ERR_DNS_IS_OK(err)) goto error;
 441
 442         /*
 443          * .. and add our IPs
 444          */
 445
 446         for ( i=0; i<num_addrs; i++ ) {
 447
 448                 switch(ss_addrs[i].ss_family) {
 449                 case AF_INET:
 450                         err = dns_create_a_record(req, hostname, 3600, &ss_addrs[i], &rec);
 451                         break;
 452 #ifdef HAVE_IPV6
 453                 case AF_INET6:
 454                         err = dns_create_aaaa_record(req, hostname, 3600, &ss_addrs[i], &rec);
 455                         break;
 456 #endif
 457                 default:
 458                         continue;
 459                 }
 460                 if (!ERR_DNS_IS_OK(err))
 461                         goto error;
 462
 463                 err = dns_add_rrec(req, rec, &req->num_updates, &req->updates);
 464                 if (!ERR_DNS_IS_OK(err))
 465                         goto error;
 466         }
 467
 468         *preq = req;
 469         return ERROR_DNS_SUCCESS;
 470
 471  error:
 472         TALLOC_FREE(req);
 473         return err;
 474 }