lib/addns/dnsquery.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    DNS utility library
   4    Copyright (C) Gerald (Jerry) Carter           2006.
   5    Copyright (C) Jeremy Allison                  2007.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19 */
  20
  21 #include "includes.h"
  22 #include "lib/util/util_net.h"
  23 #include "lib/util/tsort.h"
  24 #include "dnsquery.h"
  25
  26 /* AIX resolv.h uses 'class' in struct ns_rr */
  27
  28 #if defined(AIX)
  29 #  if defined(class)
  30 #    undef class
  31 #  endif
  32 #endif  /* AIX */
  33
  34 /* resolver headers */
  35
  36 #include <sys/types.h>
  37 #include <netinet/in.h>
  38 #include <arpa/nameser.h>
  39 #include <resolv.h>
  40 #include <netdb.h>
  41
  42 #define MAX_DNS_PACKET_SIZE 0xffff
  43
  44 #ifdef NS_HFIXEDSZ      /* Bind 8/9 interface */
  45 #if !defined(C_IN)      /* AIX 5.3 already defines C_IN */
  46 #  define C_IN          ns_c_in
  47 #endif
  48 #if !defined(T_A)       /* AIX 5.3 already defines T_A */
  49 #  define T_A           ns_t_a
  50 #endif
  51
  52 #if defined(HAVE_IPV6)
  53 #if !defined(T_AAAA)
  54 #  define T_AAAA        ns_t_aaaa
  55 #endif
  56 #endif
  57
  58 #  define T_SRV         ns_t_srv
  59 #if !defined(T_NS)      /* AIX 5.3 already defines T_NS */
  60 #  define T_NS          ns_t_ns
  61 #endif
  62 #else
  63 #  ifdef HFIXEDSZ
  64 #    define NS_HFIXEDSZ HFIXEDSZ
  65 #  else
  66 #    define NS_HFIXEDSZ sizeof(HEADER)
  67 #  endif        /* HFIXEDSZ */
  68 #  ifdef PACKETSZ
  69 #    define NS_PACKETSZ PACKETSZ
  70 #  else /* 512 is usually the default */
  71 #    define NS_PACKETSZ 512
  72 #  endif        /* PACKETSZ */
  73 #  define T_SRV         33
  74 #endif
  75
  76 /*********************************************************************
  77 *********************************************************************/
  78
  79 static bool ads_dns_parse_query( TALLOC_CTX *ctx, uint8_t *start, uint8_t *end,
  80                           uint8_t **ptr, struct dns_query *q )
  81 {
  82         uint8_t *p = *ptr;
  83         char hostname[MAX_DNS_NAME_LENGTH];
  84         int namelen;
  85
  86         ZERO_STRUCTP( q );
  87
  88         if ( !start || !end || !q || !*ptr)
  89                 return false;
  90
  91         /* See RFC 1035 for details. If this fails, then return. */
  92
  93         namelen = dn_expand( start, end, p, hostname, sizeof(hostname) );
  94         if ( namelen < 0 ) {
  95                 return false;
  96         }
  97         p += namelen;
  98         q->hostname = talloc_strdup( ctx, hostname );
  99
 100         /* check that we have space remaining */
 101
 102         if ( PTR_DIFF(p+4, end) > 0 )
 103                 return false;
 104
 105         q->type     = RSVAL( p, 0 );
 106         q->in_class = RSVAL( p, 2 );
 107         p += 4;
 108
 109         *ptr = p;
 110
 111         return true;
 112 }
 113
 114 /*********************************************************************
 115 *********************************************************************/
 116
 117 static bool ads_dns_parse_rr( TALLOC_CTX *ctx, uint8_t *start, uint8_t *end,
 118                        uint8_t **ptr, struct dns_rr *rr )
 119 {
 120         uint8_t *p = *ptr;
 121         char hostname[MAX_DNS_NAME_LENGTH];
 122         int namelen;
 123
 124         if ( !start || !end || !rr || !*ptr)
 125                 return -1;
 126
 127         ZERO_STRUCTP( rr );
 128         /* pull the name from the answer */
 129
 130         namelen = dn_expand( start, end, p, hostname, sizeof(hostname) );
 131         if ( namelen < 0 ) {
 132                 return -1;
 133         }
 134         p += namelen;
 135         rr->hostname = talloc_strdup( ctx, hostname );
 136
 137         /* check that we have space remaining */
 138
 139         if ( PTR_DIFF(p+10, end) > 0 )
 140                 return false;
 141
 142         /* pull some values and then skip onto the string */
 143
 144         rr->type     = RSVAL(p, 0);
 145         rr->in_class = RSVAL(p, 2);
 146         rr->ttl      = RIVAL(p, 4);
 147         rr->rdatalen = RSVAL(p, 8);
 148
 149         p += 10;
 150
 151         /* sanity check the available space */
 152
 153         if ( PTR_DIFF(p+rr->rdatalen, end ) > 0 ) {
 154                 return false;
 155
 156         }
 157
 158         /* save a point to the rdata for this section */
 159
 160         rr->rdata = p;
 161         p += rr->rdatalen;
 162
 163         *ptr = p;
 164
 165         return true;
 166 }
 167
 168 /*********************************************************************
 169 *********************************************************************/
 170
 171 static bool ads_dns_parse_rr_srv( TALLOC_CTX *ctx, uint8_t *start, uint8_t *end,
 172                        uint8_t **ptr, struct dns_rr_srv *srv )
 173 {
 174         struct dns_rr rr;
 175         uint8_t *p;
 176         char dcname[MAX_DNS_NAME_LENGTH];
 177         int namelen;
 178
 179         if ( !start || !end || !srv || !*ptr)
 180                 return -1;
 181
 182         /* Parse the RR entry.  Coming out of the this, ptr is at the beginning
 183            of the next record */
 184
 185         if ( !ads_dns_parse_rr( ctx, start, end, ptr, &rr ) ) {
 186                 DEBUG(1,("ads_dns_parse_rr_srv: Failed to parse RR record\n"));
 187                 return false;
 188         }
 189
 190         if ( rr.type != T_SRV ) {
 191                 DEBUG(1,("ads_dns_parse_rr_srv: Bad answer type (%d)\n",
 192                                         rr.type));
 193                 return false;
 194         }
 195
 196         p = rr.rdata;
 197
 198         srv->priority = RSVAL(p, 0);
 199         srv->weight   = RSVAL(p, 2);
 200         srv->port     = RSVAL(p, 4);
 201
 202         p += 6;
 203
 204         namelen = dn_expand( start, end, p, dcname, sizeof(dcname) );
 205         if ( namelen < 0 ) {
 206                 DEBUG(1,("ads_dns_parse_rr_srv: Failed to uncompress name!\n"));
 207                 return false;
 208         }
 209
 210         srv->hostname = talloc_strdup( ctx, dcname );
 211
 212         DEBUG(10,("ads_dns_parse_rr_srv: Parsed %s [%u, %u, %u]\n",
 213                   srv->hostname,
 214                   srv->priority,
 215                   srv->weight,
 216                   srv->port));
 217
 218         return true;
 219 }
 220
 221 /*********************************************************************
 222 *********************************************************************/
 223
 224 static bool ads_dns_parse_rr_ns( TALLOC_CTX *ctx, uint8_t *start, uint8_t *end,
 225                        uint8_t **ptr, struct dns_rr_ns *nsrec )
 226 {
 227         struct dns_rr rr;
 228         uint8_t *p;
 229         char nsname[MAX_DNS_NAME_LENGTH];
 230         int namelen;
 231
 232         if ( !start || !end || !nsrec || !*ptr)
 233                 return -1;
 234
 235         /* Parse the RR entry.  Coming out of the this, ptr is at the beginning
 236            of the next record */
 237
 238         if ( !ads_dns_parse_rr( ctx, start, end, ptr, &rr ) ) {
 239                 DEBUG(1,("ads_dns_parse_rr_ns: Failed to parse RR record\n"));
 240                 return false;
 241         }
 242
 243         if ( rr.type != T_NS ) {
 244                 DEBUG(1,("ads_dns_parse_rr_ns: Bad answer type (%d)\n",
 245                                         rr.type));
 246                 return false;
 247         }
 248
 249         p = rr.rdata;
 250
 251         /* ame server hostname */
 252
 253         namelen = dn_expand( start, end, p, nsname, sizeof(nsname) );
 254         if ( namelen < 0 ) {
 255                 DEBUG(1,("ads_dns_parse_rr_ns: Failed to uncompress name!\n"));
 256                 return false;
 257         }
 258         nsrec->hostname = talloc_strdup( ctx, nsname );
 259
 260         return true;
 261 }
 262
 263 /*********************************************************************
 264  Sort SRV record list based on weight and priority.  See RFC 2782.
 265 *********************************************************************/
 266
 267 static int dnssrvcmp( struct dns_rr_srv *a, struct dns_rr_srv *b )
 268 {
 269         if ( a->priority == b->priority ) {
 270
 271                 /* randomize entries with an equal weight and priority */
 272                 if ( a->weight == b->weight )
 273                         return 0;
 274
 275                 /* higher weights should be sorted lower */
 276                 if ( a->weight > b->weight )
 277                         return -1;
 278                 else
 279                         return 1;
 280         }
 281
 282         if ( a->priority < b->priority )
 283                 return -1;
 284
 285         return 1;
 286 }
 287
 288 /*********************************************************************
 289  Simple wrapper for a DNS query
 290 *********************************************************************/
 291
 292 #define DNS_FAILED_WAITTIME          30
 293
 294 static NTSTATUS dns_send_req( TALLOC_CTX *ctx, const char *name, int q_type,
 295                               uint8_t **buf, int *resp_length )
 296 {
 297         uint8_t *buffer = NULL;
 298         size_t buf_len = 0;
 299         int resp_len = NS_PACKETSZ;
 300         static time_t last_dns_check = 0;
 301         static NTSTATUS last_dns_status = NT_STATUS_OK;
 302         time_t now = time_mono(NULL);
 303
 304         /* Try to prevent bursts of DNS lookups if the server is down */
 305
 306         /* Protect against large clock changes */
 307
 308         if ( last_dns_check > now )
 309                 last_dns_check = 0;
 310
 311         /* IF we had a DNS timeout or a bad server and we are still
 312            in the 30 second cache window, just return the previous
 313            status and save the network timeout. */
 314
 315         if ( (NT_STATUS_EQUAL(last_dns_status,NT_STATUS_IO_TIMEOUT) ||
 316               NT_STATUS_EQUAL(last_dns_status,NT_STATUS_CONNECTION_REFUSED)) &&
 317              (last_dns_check+DNS_FAILED_WAITTIME) > now )
 318         {
 319                 DEBUG(10,("dns_send_req: last dns check returning cached status (%s)\n",
 320                           nt_errstr(last_dns_status) ));
 321                 return last_dns_status;
 322         }
 323
 324         /* Send the Query */
 325         do {
 326                 if ( buffer )
 327                         TALLOC_FREE( buffer );
 328
 329                 buf_len = resp_len * sizeof(uint8_t);
 330
 331                 if (buf_len) {
 332                         if ((buffer = talloc_array(ctx, uint8_t, buf_len))
 333                                         == NULL ) {
 334                                 DEBUG(0,("dns_send_req: "
 335                                         "talloc() failed!\n"));
 336                                 last_dns_status = NT_STATUS_NO_MEMORY;
 337                                 last_dns_check = time_mono(NULL);
 338                                 return last_dns_status;
 339                         }
 340                 }
 341
 342                 if ((resp_len = res_query(name, C_IN, q_type, buffer, buf_len))
 343                                 < 0 ) {
 344                         DEBUG(3,("dns_send_req: "
 345                                 "Failed to resolve %s (%s)\n",
 346                                 name, strerror(errno)));
 347                         TALLOC_FREE( buffer );
 348                         last_dns_status = NT_STATUS_UNSUCCESSFUL;
 349
 350                         if (errno == ETIMEDOUT) {
 351                                 last_dns_status = NT_STATUS_IO_TIMEOUT;
 352                         }
 353                         if (errno == ECONNREFUSED) {
 354                                 last_dns_status = NT_STATUS_CONNECTION_REFUSED;
 355                         }
 356                         last_dns_check = time_mono(NULL);
 357                         return last_dns_status;
 358                 }
 359
 360                 /* On AIX, Solaris, and possibly some older glibc systems (e.g. SLES8)
 361                    truncated replies never give back a resp_len > buflen
 362                    which ends up causing DNS resolve failures on large tcp DNS replies */
 363
 364                 if (buf_len == resp_len) {
 365                         if (resp_len == MAX_DNS_PACKET_SIZE) {
 366                                 DEBUG(1,("dns_send_req: DNS reply too large when resolving %s\n",
 367                                         name));
 368                                 TALLOC_FREE( buffer );
 369                                 last_dns_status = NT_STATUS_BUFFER_TOO_SMALL;
 370                                 last_dns_check = time_mono(NULL);
 371                                 return last_dns_status;
 372                         }
 373
 374                         resp_len = MIN(resp_len*2, MAX_DNS_PACKET_SIZE);
 375                 }
 376
 377
 378         } while ( buf_len < resp_len && resp_len <= MAX_DNS_PACKET_SIZE );
 379
 380         *buf = buffer;
 381         *resp_length = resp_len;
 382
 383         last_dns_check = time_mono(NULL);
 384         last_dns_status = NT_STATUS_OK;
 385         return last_dns_status;
 386 }
 387
 388 /*********************************************************************
 389  Simple wrapper for a DNS SRV query
 390 *********************************************************************/
 391
 392 NTSTATUS ads_dns_lookup_srv(TALLOC_CTX *ctx,
 393                                 const char *dns_hosts_file,
 394                                 const char *name,
 395                                 struct dns_rr_srv **dclist,
 396                                 int *numdcs)
 397 {
 398         uint8_t *buffer = NULL;
 399         int resp_len = 0;
 400         struct dns_rr_srv *dcs = NULL;
 401         int query_count, answer_count, auth_count, additional_count;
 402         uint8_t *p = buffer;
 403         int rrnum;
 404         int idx = 0;
 405         NTSTATUS status;
 406
 407         if ( !ctx || !name || !dclist ) {
 408                 return NT_STATUS_INVALID_PARAMETER;
 409         }
 410
 411         if (dns_hosts_file) {
 412                 return resolve_dns_hosts_file_as_dns_rr(dns_hosts_file,
 413                                                         name, true, ctx,
 414                                                         dclist, numdcs);
 415         }
 416
 417         /* Send the request.  May have to loop several times in case
 418            of large replies */
 419
 420         status = dns_send_req( ctx, name, T_SRV, &buffer, &resp_len );
 421         if ( !NT_STATUS_IS_OK(status) ) {
 422                 DEBUG(3,("ads_dns_lookup_srv: Failed to send DNS query (%s)\n",
 423                         nt_errstr(status)));
 424                 return status;
 425         }
 426         p = buffer;
 427
 428         /* For some insane reason, the ns_initparse() et. al. routines are only
 429            available in libresolv.a, and not the shared lib.  Who knows why....
 430            So we have to parse the DNS reply ourselves */
 431
 432         /* Pull the answer RR's count from the header.
 433          * Use the NMB ordering macros */
 434
 435         query_count      = RSVAL( p, 4 );
 436         answer_count     = RSVAL( p, 6 );
 437         auth_count       = RSVAL( p, 8 );
 438         additional_count = RSVAL( p, 10 );
 439
 440         DEBUG(4,("ads_dns_lookup_srv: "
 441                 "%d records returned in the answer section.\n",
 442                 answer_count));
 443
 444         if (answer_count) {
 445                 if ((dcs = talloc_zero_array(ctx, struct dns_rr_srv,
 446                                                 answer_count)) == NULL ) {
 447                         DEBUG(0,("ads_dns_lookup_srv: "
 448                                 "talloc() failure for %d char*'s\n",
 449                                 answer_count));
 450                         return NT_STATUS_NO_MEMORY;
 451                 }
 452         } else {
 453                 dcs = NULL;
 454         }
 455
 456         /* now skip the header */
 457
 458         p += NS_HFIXEDSZ;
 459
 460         /* parse the query section */
 461
 462         for ( rrnum=0; rrnum<query_count; rrnum++ ) {
 463                 struct dns_query q;
 464
 465                 if (!ads_dns_parse_query(ctx, buffer,
 466                                         buffer+resp_len, &p, &q)) {
 467                         DEBUG(1,("ads_dns_lookup_srv: "
 468                                  "Failed to parse query record [%d]!\n", rrnum));
 469                         return NT_STATUS_UNSUCCESSFUL;
 470                 }
 471         }
 472
 473         /* now we are at the answer section */
 474
 475         for ( rrnum=0; rrnum<answer_count; rrnum++ ) {
 476                 if (!ads_dns_parse_rr_srv(ctx, buffer, buffer+resp_len,
 477                                         &p, &dcs[rrnum])) {
 478                         DEBUG(1,("ads_dns_lookup_srv: "
 479                                  "Failed to parse answer recordi [%d]!\n", rrnum));
 480                         return NT_STATUS_UNSUCCESSFUL;
 481                 }
 482         }
 483         idx = rrnum;
 484
 485         /* Parse the authority section */
 486         /* just skip these for now */
 487
 488         for ( rrnum=0; rrnum<auth_count; rrnum++ ) {
 489                 struct dns_rr rr;
 490
 491                 if (!ads_dns_parse_rr( ctx, buffer,
 492                                         buffer+resp_len, &p, &rr)) {
 493                         DEBUG(1,("ads_dns_lookup_srv: "
 494                                  "Failed to parse authority record! [%d]\n", rrnum));
 495                         return NT_STATUS_UNSUCCESSFUL;
 496                 }
 497         }
 498
 499         /* Parse the additional records section */
 500
 501         for ( rrnum=0; rrnum<additional_count; rrnum++ ) {
 502                 struct dns_rr rr;
 503                 int i;
 504
 505                 if (!ads_dns_parse_rr(ctx, buffer, buffer+resp_len,
 506                                         &p, &rr)) {
 507                         DEBUG(1,("ads_dns_lookup_srv: Failed "
 508                                  "to parse additional records section! [%d]\n", rrnum));
 509                         return NT_STATUS_UNSUCCESSFUL;
 510                 }
 511
 512                 /* Only interested in A or AAAA records as a shortcut for having
 513                  * to come back later and lookup the name. For multi-homed
 514                  * hosts, the number of additional records and exceed the
 515                  * number of answer records. */
 516
 517                 if (rr.type != T_A || rr.rdatalen != 4) {
 518 #if defined(HAVE_IPV6)
 519                         /* RFC2874 defines A6 records. This
 520                          * requires recusive and horribly complex lookups.
 521                          * Bastards. Ignore this for now.... JRA.
 522                          * Luckily RFC3363 reprecates A6 records.
 523                          */
 524                         if (rr.type != T_AAAA || rr.rdatalen != 16)
 525 #endif
 526                                 continue;
 527                 }
 528
 529                 for ( i=0; i<idx; i++ ) {
 530                         if ( strcmp( rr.hostname, dcs[i].hostname ) == 0 ) {
 531                                 int num_ips = dcs[i].num_ips;
 532                                 struct sockaddr_storage *tmp_ss_s;
 533
 534                                 /* allocate new memory */
 535
 536                                 if (dcs[i].num_ips == 0) {
 537                                         if ((dcs[i].ss_s = talloc_array(dcs,
 538                                                 struct sockaddr_storage, 1 ))
 539                                                         == NULL ) {
 540                                                 return NT_STATUS_NO_MEMORY;
 541                                         }
 542                                 } else {
 543                                         if ((tmp_ss_s = talloc_realloc(dcs,
 544                                                         dcs[i].ss_s,
 545                                                         struct sockaddr_storage,
 546                                                         dcs[i].num_ips+1))
 547                                                                 == NULL ) {
 548                                                 return NT_STATUS_NO_MEMORY;
 549                                         }
 550
 551                                         dcs[i].ss_s = tmp_ss_s;
 552                                 }
 553                                 dcs[i].num_ips++;
 554
 555                                 /* copy the new IP address */
 556                                 if (rr.type == T_A) {
 557                                         struct in_addr ip;
 558                                         memcpy(&ip, rr.rdata, 4);
 559                                         in_addr_to_sockaddr_storage(
 560                                                         &dcs[i].ss_s[num_ips],
 561                                                         ip);
 562                                 }
 563 #if defined(HAVE_IPV6)
 564                                 if (rr.type == T_AAAA) {
 565                                         struct in6_addr ip6;
 566                                         memcpy(&ip6, rr.rdata, rr.rdatalen);
 567                                         in6_addr_to_sockaddr_storage(
 568                                                         &dcs[i].ss_s[num_ips],
 569                                                         ip6);
 570                                 }
 571 #endif
 572                         }
 573                 }
 574         }
 575
 576         TYPESAFE_QSORT(dcs, idx, dnssrvcmp );
 577
 578         *dclist = dcs;
 579         *numdcs = idx;
 580
 581         return NT_STATUS_OK;
 582 }
 583
 584 /*********************************************************************
 585  Simple wrapper for a DNS NS query
 586 *********************************************************************/
 587
 588 NTSTATUS ads_dns_lookup_ns(TALLOC_CTX *ctx,
 589                                 const char *dns_hosts_file,
 590                                 const char *dnsdomain,
 591                                 struct dns_rr_ns **nslist,
 592                                 int *numns)
 593 {
 594         uint8_t *buffer = NULL;
 595         int resp_len = 0;
 596         struct dns_rr_ns *nsarray = NULL;
 597         int query_count, answer_count, auth_count, additional_count;
 598         uint8_t *p;
 599         int rrnum;
 600         int idx = 0;
 601         NTSTATUS status;
 602
 603         if ( !ctx || !dnsdomain || !nslist ) {
 604                 return NT_STATUS_INVALID_PARAMETER;
 605         }
 606
 607         if (dns_hosts_file) {
 608                 DEBUG(1, ("NO 'NS' lookup available when using resolv:host file"));
 609                 return NT_STATUS_OBJECT_NAME_NOT_FOUND;
 610         }
 611
 612         /* Send the request.  May have to loop several times in case
 613            of large replies */
 614
 615         status = dns_send_req( ctx, dnsdomain, T_NS, &buffer, &resp_len );
 616         if ( !NT_STATUS_IS_OK(status) ) {
 617                 DEBUG(3,("ads_dns_lookup_ns: Failed to send DNS query (%s)\n",
 618                         nt_errstr(status)));
 619                 return status;
 620         }
 621         p = buffer;
 622
 623         /* For some insane reason, the ns_initparse() et. al. routines are only
 624            available in libresolv.a, and not the shared lib.  Who knows why....
 625            So we have to parse the DNS reply ourselves */
 626
 627         /* Pull the answer RR's count from the header.
 628          * Use the NMB ordering macros */
 629
 630         query_count      = RSVAL( p, 4 );
 631         answer_count     = RSVAL( p, 6 );
 632         auth_count       = RSVAL( p, 8 );
 633         additional_count = RSVAL( p, 10 );
 634
 635         DEBUG(4,("ads_dns_lookup_ns: "
 636                 "%d records returned in the answer section.\n",
 637                 answer_count));
 638
 639         if (answer_count) {
 640                 if ((nsarray = talloc_array(ctx, struct dns_rr_ns,
 641                                                 answer_count)) == NULL ) {
 642                         DEBUG(0,("ads_dns_lookup_ns: "
 643                                 "talloc() failure for %d char*'s\n",
 644                                 answer_count));
 645                         return NT_STATUS_NO_MEMORY;
 646                 }
 647         } else {
 648                 nsarray = NULL;
 649         }
 650
 651         /* now skip the header */
 652
 653         p += NS_HFIXEDSZ;
 654
 655         /* parse the query section */
 656
 657         for ( rrnum=0; rrnum<query_count; rrnum++ ) {
 658                 struct dns_query q;
 659
 660                 if (!ads_dns_parse_query(ctx, buffer, buffer+resp_len,
 661                                         &p, &q)) {
 662                         DEBUG(1,("ads_dns_lookup_ns: "
 663                                 " Failed to parse query record!\n"));
 664                         return NT_STATUS_UNSUCCESSFUL;
 665                 }
 666         }
 667
 668         /* now we are at the answer section */
 669
 670         for ( rrnum=0; rrnum<answer_count; rrnum++ ) {
 671                 if (!ads_dns_parse_rr_ns(ctx, buffer, buffer+resp_len,
 672                                         &p, &nsarray[rrnum])) {
 673                         DEBUG(1,("ads_dns_lookup_ns: "
 674                                 "Failed to parse answer record!\n"));
 675                         return NT_STATUS_UNSUCCESSFUL;
 676                 }
 677         }
 678         idx = rrnum;
 679
 680         /* Parse the authority section */
 681         /* just skip these for now */
 682
 683         for ( rrnum=0; rrnum<auth_count; rrnum++ ) {
 684                 struct dns_rr rr;
 685
 686                 if ( !ads_dns_parse_rr(ctx, buffer, buffer+resp_len,
 687                                         &p, &rr)) {
 688                         DEBUG(1,("ads_dns_lookup_ns: "
 689                                 "Failed to parse authority record!\n"));
 690                         return NT_STATUS_UNSUCCESSFUL;
 691                 }
 692         }
 693
 694         /* Parse the additional records section */
 695
 696         for ( rrnum=0; rrnum<additional_count; rrnum++ ) {
 697                 struct dns_rr rr;
 698                 int i;
 699
 700                 if (!ads_dns_parse_rr(ctx, buffer, buffer+resp_len,
 701                                         &p, &rr)) {
 702                         DEBUG(1,("ads_dns_lookup_ns: Failed "
 703                                 "to parse additional records section!\n"));
 704                         return NT_STATUS_UNSUCCESSFUL;
 705                 }
 706
 707                 /* only interested in A records as a shortcut for having to come
 708                    back later and lookup the name */
 709
 710                 if (rr.type != T_A || rr.rdatalen != 4) {
 711 #if defined(HAVE_IPV6)
 712                         if (rr.type != T_AAAA || rr.rdatalen != 16)
 713 #endif
 714                                 continue;
 715                 }
 716
 717                 for ( i=0; i<idx; i++ ) {
 718                         if (strcmp(rr.hostname, nsarray[i].hostname) == 0) {
 719                                 if (rr.type == T_A) {
 720                                         struct in_addr ip;
 721                                         memcpy(&ip, rr.rdata, 4);
 722                                         in_addr_to_sockaddr_storage(
 723                                                         &nsarray[i].ss,
 724                                                         ip);
 725                                 }
 726 #if defined(HAVE_IPV6)
 727                                 if (rr.type == T_AAAA) {
 728                                         struct in6_addr ip6;
 729                                         memcpy(&ip6, rr.rdata, rr.rdatalen);
 730                                         in6_addr_to_sockaddr_storage(
 731                                                         &nsarray[i].ss,
 732                                                         ip6);
 733                                 }
 734 #endif
 735                         }
 736                 }
 737         }
 738
 739         *nslist = nsarray;
 740         *numns = idx;
 741
 742         return NT_STATUS_OK;
 743 }
 744
 745 /********************************************************************
 746  Query with optional sitename.
 747 ********************************************************************/
 748
 749 static NTSTATUS ads_dns_query_internal(TALLOC_CTX *ctx,
 750                                        const char *dns_hosts_file,
 751                                        const char *servicename,
 752                                        const char *dc_pdc_gc_domains,
 753                                        const char *realm,
 754                                        const char *sitename,
 755                                        struct dns_rr_srv **dclist,
 756                                        int *numdcs )
 757 {
 758         char *name;
 759         if (sitename && strlen(sitename)) {
 760                 name = talloc_asprintf(ctx, "%s._tcp.%s._sites.%s._msdcs.%s",
 761                                        servicename, sitename,
 762                                        dc_pdc_gc_domains, realm);
 763         } else {
 764                 name = talloc_asprintf(ctx, "%s._tcp.%s._msdcs.%s",
 765                                 servicename, dc_pdc_gc_domains, realm);
 766         }
 767         if (!name) {
 768                 return NT_STATUS_NO_MEMORY;
 769         }
 770         return ads_dns_lookup_srv(ctx, dns_hosts_file, name, dclist, numdcs);
 771 }
 772
 773 /********************************************************************
 774  Query for AD DC's.
 775 ********************************************************************/
 776
 777 NTSTATUS ads_dns_query_dcs(TALLOC_CTX *ctx,
 778                            const char *dns_hosts_file,
 779                            const char *realm,
 780                            const char *sitename,
 781                            struct dns_rr_srv **dclist,
 782                            int *numdcs )
 783 {
 784         NTSTATUS status;
 785
 786         status = ads_dns_query_internal(ctx, dns_hosts_file, "_ldap", "dc",
 787                                         realm, sitename, dclist, numdcs);
 788
 789         if (NT_STATUS_EQUAL(status, NT_STATUS_IO_TIMEOUT) ||
 790             NT_STATUS_EQUAL(status, NT_STATUS_CONNECTION_REFUSED)) {
 791                 return status;
 792         }
 793
 794         if (sitename &&
 795             ((!NT_STATUS_IS_OK(status)) ||
 796              (NT_STATUS_IS_OK(status) && (numdcs == 0)))) {
 797                 /* Sitename DNS query may have failed. Try without. */
 798                 status = ads_dns_query_internal(ctx, dns_hosts_file,
 799                                                 "_ldap", "dc", realm,
 800                                                 NULL, dclist, numdcs);
 801         }
 802         return status;
 803 }
 804
 805 /********************************************************************
 806  Query for AD GC's.
 807 ********************************************************************/
 808
 809 NTSTATUS ads_dns_query_gcs(TALLOC_CTX *ctx,
 810                            const char *dns_hosts_file,
 811                            const char *realm,
 812                            const char *sitename,
 813                            struct dns_rr_srv **dclist,
 814                            int *numdcs )
 815 {
 816         NTSTATUS status;
 817
 818         status = ads_dns_query_internal(ctx, dns_hosts_file, "_ldap", "gc",
 819                                         realm, sitename, dclist, numdcs);
 820
 821         if (NT_STATUS_EQUAL(status, NT_STATUS_IO_TIMEOUT) ||
 822             NT_STATUS_EQUAL(status, NT_STATUS_CONNECTION_REFUSED)) {
 823                 return status;
 824         }
 825
 826         if (sitename &&
 827             ((!NT_STATUS_IS_OK(status)) ||
 828              (NT_STATUS_IS_OK(status) && (numdcs == 0)))) {
 829                 /* Sitename DNS query may have failed. Try without. */
 830                 status = ads_dns_query_internal(ctx, dns_hosts_file,
 831                                                 "_ldap", "gc", realm,
 832                                                 NULL, dclist, numdcs);
 833         }
 834         return status;
 835 }
 836
 837 /********************************************************************
 838  Query for AD KDC's.
 839  Even if our underlying kerberos libraries are UDP only, this
 840  is pretty safe as it's unlikely that a KDC supports TCP and not UDP.
 841 ********************************************************************/
 842
 843 NTSTATUS ads_dns_query_kdcs(TALLOC_CTX *ctx,
 844                             const char *dns_hosts_file,
 845                             const char *dns_forest_name,
 846                             const char *sitename,
 847                             struct dns_rr_srv **dclist,
 848                             int *numdcs )
 849 {
 850         NTSTATUS status;
 851
 852         status = ads_dns_query_internal(ctx, dns_hosts_file, "_kerberos", "dc",
 853                                         dns_forest_name, sitename, dclist,
 854                                         numdcs);
 855
 856         if (NT_STATUS_EQUAL(status, NT_STATUS_IO_TIMEOUT) ||
 857             NT_STATUS_EQUAL(status, NT_STATUS_CONNECTION_REFUSED)) {
 858                 return status;
 859         }
 860
 861         if (sitename &&
 862             ((!NT_STATUS_IS_OK(status)) ||
 863              (NT_STATUS_IS_OK(status) && (numdcs == 0)))) {
 864                 /* Sitename DNS query may have failed. Try without. */
 865                 status = ads_dns_query_internal(ctx, dns_hosts_file,
 866                                                 "_kerberos", "dc",
 867                                                 dns_forest_name, NULL,
 868                                                 dclist, numdcs);
 869         }
 870         return status;
 871 }
 872
 873 /********************************************************************
 874  Query for AD PDC. Sitename is obsolete here.
 875 ********************************************************************/
 876
 877 NTSTATUS ads_dns_query_pdc(TALLOC_CTX *ctx,
 878                            const char *dns_hosts_file,
 879                            const char *dns_domain_name,
 880                            struct dns_rr_srv **dclist,
 881                            int *numdcs )
 882 {
 883         return ads_dns_query_internal(ctx, dns_hosts_file, "_ldap", "pdc",
 884                                       dns_domain_name, NULL, dclist, numdcs);
 885 }
 886
 887 /********************************************************************
 888  Query for AD DC by guid. Sitename is obsolete here.
 889 ********************************************************************/
 890
 891 NTSTATUS ads_dns_query_dcs_guid(TALLOC_CTX *ctx,
 892                                 const char *dns_hosts_file,
 893                                 const char *dns_forest_name,
 894                                 const char *domain_guid,
 895                                 struct dns_rr_srv **dclist,
 896                                 int *numdcs )
 897 {
 898         /*_ldap._tcp.DomainGuid.domains._msdcs.DnsForestName */
 899
 900         const char *domains;
 901
 902         /* little hack */
 903         domains = talloc_asprintf(ctx, "%s.domains", domain_guid);
 904         if (!domains) {
 905                 return NT_STATUS_NO_MEMORY;
 906         }
 907
 908         return ads_dns_query_internal(ctx, dns_hosts_file, "_ldap", domains,
 909                                       dns_forest_name, NULL, dclist, numdcs);
 910 }