source3/libads/dns.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 "libads/dns.h"
  23
  24 /* AIX resolv.h uses 'class' in struct ns_rr */
  25
  26 #if defined(AIX)
  27 #  if defined(class)
  28 #    undef class
  29 #  endif
  30 #endif  /* AIX */
  31
  32 /* resolver headers */
  33
  34 #include <sys/types.h>
  35 #include <netinet/in.h>
  36 #include <arpa/nameser.h>
  37 #include <resolv.h>
  38 #include <netdb.h>
  39
  40 #define MAX_DNS_PACKET_SIZE 0xffff
  41
  42 #ifdef NS_HFIXEDSZ      /* Bind 8/9 interface */
  43 #if !defined(C_IN)      /* AIX 5.3 already defines C_IN */
  44 #  define C_IN          ns_c_in
  45 #endif
  46 #if !defined(T_A)       /* AIX 5.3 already defines T_A */
  47 #  define T_A           ns_t_a
  48 #endif
  49
  50 #if defined(HAVE_IPV6)
  51 #if !defined(T_AAAA)
  52 #  define T_AAAA        ns_t_aaaa
  53 #endif
  54 #endif
  55
  56 #  define T_SRV         ns_t_srv
  57 #if !defined(T_NS)      /* AIX 5.3 already defines T_NS */
  58 #  define T_NS          ns_t_ns
  59 #endif
  60 #else
  61 #  ifdef HFIXEDSZ
  62 #    define NS_HFIXEDSZ HFIXEDSZ
  63 #  else
  64 #    define NS_HFIXEDSZ sizeof(HEADER)
  65 #  endif        /* HFIXEDSZ */
  66 #  ifdef PACKETSZ
  67 #    define NS_PACKETSZ PACKETSZ
  68 #  else /* 512 is usually the default */
  69 #    define NS_PACKETSZ 512
  70 #  endif        /* PACKETSZ */
  71 #  define T_SRV         33
  72 #endif
  73
  74 /*********************************************************************
  75 *********************************************************************/
  76
  77 static bool ads_dns_parse_query( TALLOC_CTX *ctx, uint8 *start, uint8 *end,
  78                           uint8 **ptr, struct dns_query *q )
  79 {
  80         uint8 *p = *ptr;
  81         char hostname[MAX_DNS_NAME_LENGTH];
  82         int namelen;
  83
  84         ZERO_STRUCTP( q );
  85
  86         if ( !start || !end || !q || !*ptr)
  87                 return False;
  88
  89         /* See RFC 1035 for details. If this fails, then return. */
  90
  91         namelen = dn_expand( start, end, p, hostname, sizeof(hostname) );
  92         if ( namelen < 0 ) {
  93                 return False;
  94         }
  95         p += namelen;
  96         q->hostname = talloc_strdup( ctx, hostname );
  97
  98         /* check that we have space remaining */
  99
 100         if ( PTR_DIFF(p+4, end) > 0 )
 101                 return False;
 102
 103         q->type     = RSVAL( p, 0 );
 104         q->in_class = RSVAL( p, 2 );
 105         p += 4;
 106
 107         *ptr = p;
 108
 109         return True;
 110 }
 111
 112 /*********************************************************************
 113 *********************************************************************/
 114
 115 static bool ads_dns_parse_rr( TALLOC_CTX *ctx, uint8 *start, uint8 *end,
 116                        uint8 **ptr, struct dns_rr *rr )
 117 {
 118         uint8 *p = *ptr;
 119         char hostname[MAX_DNS_NAME_LENGTH];
 120         int namelen;
 121
 122         if ( !start || !end || !rr || !*ptr)
 123                 return -1;
 124
 125         ZERO_STRUCTP( rr );
 126         /* pull the name from the answer */
 127
 128         namelen = dn_expand( start, end, p, hostname, sizeof(hostname) );
 129         if ( namelen < 0 ) {
 130                 return -1;
 131         }
 132         p += namelen;
 133         rr->hostname = talloc_strdup( ctx, hostname );
 134
 135         /* check that we have space remaining */
 136
 137         if ( PTR_DIFF(p+10, end) > 0 )
 138                 return False;
 139
 140         /* pull some values and then skip onto the string */
 141
 142         rr->type     = RSVAL(p, 0);
 143         rr->in_class = RSVAL(p, 2);
 144         rr->ttl      = RIVAL(p, 4);
 145         rr->rdatalen = RSVAL(p, 8);
 146
 147         p += 10;
 148
 149         /* sanity check the available space */
 150
 151         if ( PTR_DIFF(p+rr->rdatalen, end ) > 0 ) {
 152                 return False;
 153
 154         }
 155
 156         /* save a point to the rdata for this section */
 157
 158         rr->rdata = p;
 159         p += rr->rdatalen;
 160
 161         *ptr = p;
 162
 163         return True;
 164 }
 165
 166 /*********************************************************************
 167 *********************************************************************/
 168
 169 static bool ads_dns_parse_rr_srv( TALLOC_CTX *ctx, uint8 *start, uint8 *end,
 170                        uint8 **ptr, struct dns_rr_srv *srv )
 171 {
 172         struct dns_rr rr;
 173         uint8 *p;
 174         char dcname[MAX_DNS_NAME_LENGTH];
 175         int namelen;
 176
 177         if ( !start || !end || !srv || !*ptr)
 178                 return -1;
 179
 180         /* Parse the RR entry.  Coming out of the this, ptr is at the beginning
 181            of the next record */
 182
 183         if ( !ads_dns_parse_rr( ctx, start, end, ptr, &rr ) ) {
 184                 DEBUG(1,("ads_dns_parse_rr_srv: Failed to parse RR record\n"));
 185                 return False;
 186         }
 187
 188         if ( rr.type != T_SRV ) {
 189                 DEBUG(1,("ads_dns_parse_rr_srv: Bad answer type (%d)\n",
 190                                         rr.type));
 191                 return False;
 192         }
 193
 194         p = rr.rdata;
 195
 196         srv->priority = RSVAL(p, 0);
 197         srv->weight   = RSVAL(p, 2);
 198         srv->port     = RSVAL(p, 4);
 199
 200         p += 6;
 201
 202         namelen = dn_expand( start, end, p, dcname, sizeof(dcname) );
 203         if ( namelen < 0 ) {
 204                 DEBUG(1,("ads_dns_parse_rr_srv: Failed to uncompress name!\n"));
 205                 return False;
 206         }
 207
 208         srv->hostname = talloc_strdup( ctx, dcname );
 209
 210         DEBUG(10,("ads_dns_parse_rr_srv: Parsed %s [%u, %u, %u]\n",
 211                   srv->hostname,
 212                   srv->priority,
 213                   srv->weight,
 214                   srv->port));
 215
 216         return True;
 217 }
 218
 219 /*********************************************************************
 220 *********************************************************************/
 221
 222 static bool ads_dns_parse_rr_ns( TALLOC_CTX *ctx, uint8 *start, uint8 *end,
 223                        uint8 **ptr, struct dns_rr_ns *nsrec )
 224 {
 225         struct dns_rr rr;
 226         uint8 *p;
 227         char nsname[MAX_DNS_NAME_LENGTH];
 228         int namelen;
 229
 230         if ( !start || !end || !nsrec || !*ptr)
 231                 return -1;
 232
 233         /* Parse the RR entry.  Coming out of the this, ptr is at the beginning
 234            of the next record */
 235
 236         if ( !ads_dns_parse_rr( ctx, start, end, ptr, &rr ) ) {
 237                 DEBUG(1,("ads_dns_parse_rr_ns: Failed to parse RR record\n"));
 238                 return False;
 239         }
 240
 241         if ( rr.type != T_NS ) {
 242                 DEBUG(1,("ads_dns_parse_rr_ns: Bad answer type (%d)\n",
 243                                         rr.type));
 244                 return False;
 245         }
 246
 247         p = rr.rdata;
 248
 249         /* ame server hostname */
 250
 251         namelen = dn_expand( start, end, p, nsname, sizeof(nsname) );
 252         if ( namelen < 0 ) {
 253                 DEBUG(1,("ads_dns_parse_rr_ns: Failed to uncompress name!\n"));
 254                 return False;
 255         }
 256         nsrec->hostname = talloc_strdup( ctx, nsname );
 257
 258         return True;
 259 }
 260
 261 /*********************************************************************
 262  Sort SRV record list based on weight and priority.  See RFC 2782.
 263 *********************************************************************/
 264
 265 static int dnssrvcmp( struct dns_rr_srv *a, struct dns_rr_srv *b )
 266 {
 267         if ( a->priority == b->priority ) {
 268
 269                 /* randomize entries with an equal weight and priority */
 270                 if ( a->weight == b->weight )
 271                         return 0;
 272
 273                 /* higher weights should be sorted lower */
 274                 if ( a->weight > b->weight )
 275                         return -1;
 276                 else
 277                         return 1;
 278         }
 279
 280         if ( a->priority < b->priority )
 281                 return -1;
 282
 283         return 1;
 284 }
 285
 286 /*********************************************************************
 287  Simple wrapper for a DNS query
 288 *********************************************************************/
 289
 290 #define DNS_FAILED_WAITTIME          30
 291
 292 static NTSTATUS dns_send_req( TALLOC_CTX *ctx, const char *name, int q_type,
 293                               uint8 **buf, int *resp_length )
 294 {
 295         uint8 *buffer = NULL;
 296         size_t buf_len = 0;
 297         int resp_len = NS_PACKETSZ;
 298         static time_t last_dns_check = 0;
 299         static NTSTATUS last_dns_status = NT_STATUS_OK;
 300         time_t now = time_mono(NULL);
 301
 302         /* Try to prevent bursts of DNS lookups if the server is down */
 303
 304         /* Protect against large clock changes */
 305
 306         if ( last_dns_check > now )
 307                 last_dns_check = 0;
 308
 309         /* IF we had a DNS timeout or a bad server and we are still
 310            in the 30 second cache window, just return the previous
 311            status and save the network timeout. */
 312
 313         if ( (NT_STATUS_EQUAL(last_dns_status,NT_STATUS_IO_TIMEOUT) ||
 314               NT_STATUS_EQUAL(last_dns_status,NT_STATUS_CONNECTION_REFUSED)) &&
 315              (last_dns_check+DNS_FAILED_WAITTIME) > now )
 316         {
 317                 DEBUG(10,("last_dns_check: Returning cached status (%s)\n",
 318                           nt_errstr(last_dns_status) ));
 319                 return last_dns_status;
 320         }
 321
 322         /* Send the Query */
 323         do {
 324                 if ( buffer )
 325                         TALLOC_FREE( buffer );
 326
 327                 buf_len = resp_len * sizeof(uint8);
 328
 329                 if (buf_len) {
 330                         if ((buffer = TALLOC_ARRAY(ctx, uint8, buf_len))
 331                                         == NULL ) {
 332                                 DEBUG(0,("ads_dns_lookup_srv: "
 333                                         "talloc() failed!\n"));
 334                                 last_dns_status = NT_STATUS_NO_MEMORY;
 335                                 last_dns_check = time_mono(NULL);
 336                                 return last_dns_status;
 337                         }
 338                 }
 339
 340                 if ((resp_len = res_query(name, C_IN, q_type, buffer, buf_len))
 341                                 < 0 ) {
 342                         DEBUG(3,("ads_dns_lookup_srv: "
 343                                 "Failed to resolve %s (%s)\n",
 344                                 name, strerror(errno)));
 345                         TALLOC_FREE( buffer );
 346                         last_dns_status = NT_STATUS_UNSUCCESSFUL;
 347
 348                         if (errno == ETIMEDOUT) {
 349                                 last_dns_status = NT_STATUS_IO_TIMEOUT;
 350                         }
 351                         if (errno == ECONNREFUSED) {
 352                                 last_dns_status = NT_STATUS_CONNECTION_REFUSED;
 353                         }
 354                         last_dns_check = time_mono(NULL);
 355                         return last_dns_status;
 356                 }
 357
 358                 /* On AIX, Solaris, and possibly some older glibc systems (e.g. SLES8)
 359                    truncated replies never give back a resp_len > buflen
 360                    which ends up causing DNS resolve failures on large tcp DNS replies */
 361
 362                 if (buf_len == resp_len) {
 363                         if (resp_len == MAX_DNS_PACKET_SIZE) {
 364                                 DEBUG(1,("dns_send_req: DNS reply too large when resolving %s\n",
 365                                         name));
 366                                 TALLOC_FREE( buffer );
 367                                 last_dns_status = NT_STATUS_BUFFER_TOO_SMALL;
 368                                 last_dns_check = time_mono(NULL);
 369                                 return last_dns_status;
 370                         }
 371
 372                         resp_len = MIN(resp_len*2, MAX_DNS_PACKET_SIZE);
 373                 }
 374
 375
 376         } while ( buf_len < resp_len && resp_len <= MAX_DNS_PACKET_SIZE );
 377
 378         *buf = buffer;
 379         *resp_length = resp_len;
 380
 381         last_dns_check = time_mono(NULL);
 382         last_dns_status = NT_STATUS_OK;
 383         return last_dns_status;
 384 }
 385
 386 /*********************************************************************
 387  Simple wrapper for a DNS SRV query
 388 *********************************************************************/
 389
 390 static NTSTATUS ads_dns_lookup_srv( TALLOC_CTX *ctx,
 391                                 const char *name,
 392                                 struct dns_rr_srv **dclist,
 393                                 int *numdcs)
 394 {
 395         uint8 *buffer = NULL;
 396         int resp_len = 0;
 397         struct dns_rr_srv *dcs = NULL;
 398         int query_count, answer_count, auth_count, additional_count;
 399         uint8 *p = buffer;
 400         int rrnum;
 401         int idx = 0;
 402         NTSTATUS status;
 403
 404         if ( !ctx || !name || !dclist ) {
 405                 return NT_STATUS_INVALID_PARAMETER;
 406         }
 407
 408         /* Send the request.  May have to loop several times in case
 409            of large replies */
 410
 411         status = dns_send_req( ctx, name, T_SRV, &buffer, &resp_len );
 412         if ( !NT_STATUS_IS_OK(status) ) {
 413                 DEBUG(3,("ads_dns_lookup_srv: Failed to send DNS query (%s)\n",
 414                         nt_errstr(status)));
 415                 return status;
 416         }
 417         p = buffer;
 418
 419         /* For some insane reason, the ns_initparse() et. al. routines are only
 420            available in libresolv.a, and not the shared lib.  Who knows why....
 421            So we have to parse the DNS reply ourselves */
 422
 423         /* Pull the answer RR's count from the header.
 424          * Use the NMB ordering macros */
 425
 426         query_count      = RSVAL( p, 4 );
 427         answer_count     = RSVAL( p, 6 );
 428         auth_count       = RSVAL( p, 8 );
 429         additional_count = RSVAL( p, 10 );
 430
 431         DEBUG(4,("ads_dns_lookup_srv: "
 432                 "%d records returned in the answer section.\n",
 433                 answer_count));
 434
 435         if (answer_count) {
 436                 if ((dcs = TALLOC_ZERO_ARRAY(ctx, struct dns_rr_srv,
 437                                                 answer_count)) == NULL ) {
 438                         DEBUG(0,("ads_dns_lookup_srv: "
 439                                 "talloc() failure for %d char*'s\n",
 440                                 answer_count));
 441                         return NT_STATUS_NO_MEMORY;
 442                 }
 443         } else {
 444                 dcs = NULL;
 445         }
 446
 447         /* now skip the header */
 448
 449         p += NS_HFIXEDSZ;
 450
 451         /* parse the query section */
 452
 453         for ( rrnum=0; rrnum<query_count; rrnum++ ) {
 454                 struct dns_query q;
 455
 456                 if (!ads_dns_parse_query(ctx, buffer,
 457                                         buffer+resp_len, &p, &q)) {
 458                         DEBUG(1,("ads_dns_lookup_srv: "
 459                                  "Failed to parse query record [%d]!\n", rrnum));
 460                         return NT_STATUS_UNSUCCESSFUL;
 461                 }
 462         }
 463
 464         /* now we are at the answer section */
 465
 466         for ( rrnum=0; rrnum<answer_count; rrnum++ ) {
 467                 if (!ads_dns_parse_rr_srv(ctx, buffer, buffer+resp_len,
 468                                         &p, &dcs[rrnum])) {
 469                         DEBUG(1,("ads_dns_lookup_srv: "
 470                                  "Failed to parse answer recordi [%d]!\n", rrnum));
 471                         return NT_STATUS_UNSUCCESSFUL;
 472                 }
 473         }
 474         idx = rrnum;
 475
 476         /* Parse the authority section */
 477         /* just skip these for now */
 478
 479         for ( rrnum=0; rrnum<auth_count; rrnum++ ) {
 480                 struct dns_rr rr;
 481
 482                 if (!ads_dns_parse_rr( ctx, buffer,
 483                                         buffer+resp_len, &p, &rr)) {
 484                         DEBUG(1,("ads_dns_lookup_srv: "
 485                                  "Failed to parse authority record! [%d]\n", rrnum));
 486                         return NT_STATUS_UNSUCCESSFUL;
 487                 }
 488         }
 489
 490         /* Parse the additional records section */
 491
 492         for ( rrnum=0; rrnum<additional_count; rrnum++ ) {
 493                 struct dns_rr rr;
 494                 int i;
 495
 496                 if (!ads_dns_parse_rr(ctx, buffer, buffer+resp_len,
 497                                         &p, &rr)) {
 498                         DEBUG(1,("ads_dns_lookup_srv: Failed "
 499                                  "to parse additional records section! [%d]\n", rrnum));
 500                         return NT_STATUS_UNSUCCESSFUL;
 501                 }
 502
 503                 /* Only interested in A or AAAA records as a shortcut for having
 504                  * to come back later and lookup the name. For multi-homed
 505                  * hosts, the number of additional records and exceed the
 506                  * number of answer records. */
 507
 508                 if (rr.type != T_A || rr.rdatalen != 4) {
 509 #if defined(HAVE_IPV6)
 510                         /* RFC2874 defines A6 records. This
 511                          * requires recusive and horribly complex lookups.
 512                          * Bastards. Ignore this for now.... JRA.
 513                          * Luckily RFC3363 reprecates A6 records.
 514                          */
 515                         if (rr.type != T_AAAA || rr.rdatalen != 16)
 516 #endif
 517                                 continue;
 518                 }
 519
 520                 for ( i=0; i<idx; i++ ) {
 521                         if ( strcmp( rr.hostname, dcs[i].hostname ) == 0 ) {
 522                                 int num_ips = dcs[i].num_ips;
 523                                 struct sockaddr_storage *tmp_ss_s;
 524
 525                                 /* allocate new memory */
 526
 527                                 if (dcs[i].num_ips == 0) {
 528                                         if ((dcs[i].ss_s = TALLOC_ARRAY(dcs,
 529                                                 struct sockaddr_storage, 1 ))
 530                                                         == NULL ) {
 531                                                 return NT_STATUS_NO_MEMORY;
 532                                         }
 533                                 } else {
 534                                         if ((tmp_ss_s = TALLOC_REALLOC_ARRAY(dcs,
 535                                                         dcs[i].ss_s,
 536                                                         struct sockaddr_storage,
 537                                                         dcs[i].num_ips+1))
 538                                                                 == NULL ) {
 539                                                 return NT_STATUS_NO_MEMORY;
 540                                         }
 541
 542                                         dcs[i].ss_s = tmp_ss_s;
 543                                 }
 544                                 dcs[i].num_ips++;
 545
 546                                 /* copy the new IP address */
 547                                 if (rr.type == T_A) {
 548                                         struct in_addr ip;
 549                                         memcpy(&ip, rr.rdata, 4);
 550                                         in_addr_to_sockaddr_storage(
 551                                                         &dcs[i].ss_s[num_ips],
 552                                                         ip);
 553                                 }
 554 #if defined(HAVE_IPV6)
 555                                 if (rr.type == T_AAAA) {
 556                                         struct in6_addr ip6;
 557                                         memcpy(&ip6, rr.rdata, rr.rdatalen);
 558                                         in6_addr_to_sockaddr_storage(
 559                                                         &dcs[i].ss_s[num_ips],
 560                                                         ip6);
 561                                 }
 562 #endif
 563                         }
 564                 }
 565         }
 566
 567         TYPESAFE_QSORT(dcs, idx, dnssrvcmp );
 568
 569         *dclist = dcs;
 570         *numdcs = idx;
 571
 572         return NT_STATUS_OK;
 573 }
 574
 575 /*********************************************************************
 576  Simple wrapper for a DNS NS query
 577 *********************************************************************/
 578
 579 NTSTATUS ads_dns_lookup_ns(TALLOC_CTX *ctx,
 580                                 const char *dnsdomain,
 581                                 struct dns_rr_ns **nslist,
 582                                 int *numns)
 583 {
 584         uint8 *buffer = NULL;
 585         int resp_len = 0;
 586         struct dns_rr_ns *nsarray = NULL;
 587         int query_count, answer_count, auth_count, additional_count;
 588         uint8 *p;
 589         int rrnum;
 590         int idx = 0;
 591         NTSTATUS status;
 592
 593         if ( !ctx || !dnsdomain || !nslist ) {
 594                 return NT_STATUS_INVALID_PARAMETER;
 595         }
 596
 597         /* Send the request.  May have to loop several times in case
 598            of large replies */
 599
 600         status = dns_send_req( ctx, dnsdomain, T_NS, &buffer, &resp_len );
 601         if ( !NT_STATUS_IS_OK(status) ) {
 602                 DEBUG(3,("ads_dns_lookup_ns: Failed to send DNS query (%s)\n",
 603                         nt_errstr(status)));
 604                 return status;
 605         }
 606         p = buffer;
 607
 608         /* For some insane reason, the ns_initparse() et. al. routines are only
 609            available in libresolv.a, and not the shared lib.  Who knows why....
 610            So we have to parse the DNS reply ourselves */
 611
 612         /* Pull the answer RR's count from the header.
 613          * Use the NMB ordering macros */
 614
 615         query_count      = RSVAL( p, 4 );
 616         answer_count     = RSVAL( p, 6 );
 617         auth_count       = RSVAL( p, 8 );
 618         additional_count = RSVAL( p, 10 );
 619
 620         DEBUG(4,("ads_dns_lookup_ns: "
 621                 "%d records returned in the answer section.\n",
 622                 answer_count));
 623
 624         if (answer_count) {
 625                 if ((nsarray = TALLOC_ARRAY(ctx, struct dns_rr_ns,
 626                                                 answer_count)) == NULL ) {
 627                         DEBUG(0,("ads_dns_lookup_ns: "
 628                                 "talloc() failure for %d char*'s\n",
 629                                 answer_count));
 630                         return NT_STATUS_NO_MEMORY;
 631                 }
 632         } else {
 633                 nsarray = NULL;
 634         }
 635
 636         /* now skip the header */
 637
 638         p += NS_HFIXEDSZ;
 639
 640         /* parse the query section */
 641
 642         for ( rrnum=0; rrnum<query_count; rrnum++ ) {
 643                 struct dns_query q;
 644
 645                 if (!ads_dns_parse_query(ctx, buffer, buffer+resp_len,
 646                                         &p, &q)) {
 647                         DEBUG(1,("ads_dns_lookup_ns: "
 648                                 " Failed to parse query record!\n"));
 649                         return NT_STATUS_UNSUCCESSFUL;
 650                 }
 651         }
 652
 653         /* now we are at the answer section */
 654
 655         for ( rrnum=0; rrnum<answer_count; rrnum++ ) {
 656                 if (!ads_dns_parse_rr_ns(ctx, buffer, buffer+resp_len,
 657                                         &p, &nsarray[rrnum])) {
 658                         DEBUG(1,("ads_dns_lookup_ns: "
 659                                 "Failed to parse answer record!\n"));
 660                         return NT_STATUS_UNSUCCESSFUL;
 661                 }
 662         }
 663         idx = rrnum;
 664
 665         /* Parse the authority section */
 666         /* just skip these for now */
 667
 668         for ( rrnum=0; rrnum<auth_count; rrnum++ ) {
 669                 struct dns_rr rr;
 670
 671                 if ( !ads_dns_parse_rr(ctx, buffer, buffer+resp_len,
 672                                         &p, &rr)) {
 673                         DEBUG(1,("ads_dns_lookup_ns: "
 674                                 "Failed to parse authority record!\n"));
 675                         return NT_STATUS_UNSUCCESSFUL;
 676                 }
 677         }
 678
 679         /* Parse the additional records section */
 680
 681         for ( rrnum=0; rrnum<additional_count; rrnum++ ) {
 682                 struct dns_rr rr;
 683                 int i;
 684
 685                 if (!ads_dns_parse_rr(ctx, buffer, buffer+resp_len,
 686                                         &p, &rr)) {
 687                         DEBUG(1,("ads_dns_lookup_ns: Failed "
 688                                 "to parse additional records section!\n"));
 689                         return NT_STATUS_UNSUCCESSFUL;
 690                 }
 691
 692                 /* only interested in A records as a shortcut for having to come
 693                    back later and lookup the name */
 694
 695                 if (rr.type != T_A || rr.rdatalen != 4) {
 696 #if defined(HAVE_IPV6)
 697                         if (rr.type != T_AAAA || rr.rdatalen != 16)
 698 #endif
 699                                 continue;
 700                 }
 701
 702                 for ( i=0; i<idx; i++ ) {
 703                         if (strcmp(rr.hostname, nsarray[i].hostname) == 0) {
 704                                 if (rr.type == T_A) {
 705                                         struct in_addr ip;
 706                                         memcpy(&ip, rr.rdata, 4);
 707                                         in_addr_to_sockaddr_storage(
 708                                                         &nsarray[i].ss,
 709                                                         ip);
 710                                 }
 711 #if defined(HAVE_IPV6)
 712                                 if (rr.type == T_AAAA) {
 713                                         struct in6_addr ip6;
 714                                         memcpy(&ip6, rr.rdata, rr.rdatalen);
 715                                         in6_addr_to_sockaddr_storage(
 716                                                         &nsarray[i].ss,
 717                                                         ip6);
 718                                 }
 719 #endif
 720                         }
 721                 }
 722         }
 723
 724         *nslist = nsarray;
 725         *numns = idx;
 726
 727         return NT_STATUS_OK;
 728 }
 729
 730 /********************************************************************
 731  Query with optional sitename.
 732 ********************************************************************/
 733
 734 static NTSTATUS ads_dns_query_internal(TALLOC_CTX *ctx,
 735                                        const char *servicename,
 736                                        const char *dc_pdc_gc_domains,
 737                                        const char *realm,
 738                                        const char *sitename,
 739                                        struct dns_rr_srv **dclist,
 740                                        int *numdcs )
 741 {
 742         char *name;
 743         if (sitename) {
 744                 name = talloc_asprintf(ctx, "%s._tcp.%s._sites.%s._msdcs.%s",
 745                                        servicename, sitename,
 746                                        dc_pdc_gc_domains, realm);
 747         } else {
 748                 name = talloc_asprintf(ctx, "%s._tcp.%s._msdcs.%s",
 749                                 servicename, dc_pdc_gc_domains, realm);
 750         }
 751         if (!name) {
 752                 return NT_STATUS_NO_MEMORY;
 753         }
 754         return ads_dns_lookup_srv( ctx, name, dclist, numdcs );
 755 }
 756
 757 /********************************************************************
 758  Query for AD DC's.
 759 ********************************************************************/
 760
 761 NTSTATUS ads_dns_query_dcs(TALLOC_CTX *ctx,
 762                            const char *realm,
 763                            const char *sitename,
 764                            struct dns_rr_srv **dclist,
 765                            int *numdcs )
 766 {
 767         NTSTATUS status;
 768
 769         status = ads_dns_query_internal(ctx, "_ldap", "dc", realm, sitename,
 770                                         dclist, numdcs);
 771
 772         if (NT_STATUS_EQUAL(status, NT_STATUS_IO_TIMEOUT) ||
 773             NT_STATUS_EQUAL(status, NT_STATUS_CONNECTION_REFUSED)) {
 774                 return status;
 775         }
 776
 777         if (sitename &&
 778             ((!NT_STATUS_IS_OK(status)) ||
 779              (NT_STATUS_IS_OK(status) && (numdcs == 0)))) {
 780                 /* Sitename DNS query may have failed. Try without. */
 781                 status = ads_dns_query_internal(ctx, "_ldap", "dc", realm,
 782                                                 NULL, dclist, numdcs);
 783         }
 784         return status;
 785 }
 786
 787 /********************************************************************
 788  Query for AD GC's.
 789 ********************************************************************/
 790
 791 NTSTATUS ads_dns_query_gcs(TALLOC_CTX *ctx,
 792                            const char *realm,
 793                            const char *sitename,
 794                            struct dns_rr_srv **dclist,
 795                            int *numdcs )
 796 {
 797         NTSTATUS status;
 798
 799         status = ads_dns_query_internal(ctx, "_ldap", "gc", realm, sitename,
 800                                         dclist, numdcs);
 801
 802         if (NT_STATUS_EQUAL(status, NT_STATUS_IO_TIMEOUT) ||
 803             NT_STATUS_EQUAL(status, NT_STATUS_CONNECTION_REFUSED)) {
 804                 return status;
 805         }
 806
 807         if (sitename &&
 808             ((!NT_STATUS_IS_OK(status)) ||
 809              (NT_STATUS_IS_OK(status) && (numdcs == 0)))) {
 810                 /* Sitename DNS query may have failed. Try without. */
 811                 status = ads_dns_query_internal(ctx, "_ldap", "gc", realm,
 812                                                 NULL, dclist, numdcs);
 813         }
 814         return status;
 815 }
 816
 817 /********************************************************************
 818  Query for AD KDC's.
 819  Even if our underlying kerberos libraries are UDP only, this
 820  is pretty safe as it's unlikely that a KDC supports TCP and not UDP.
 821 ********************************************************************/
 822
 823 NTSTATUS ads_dns_query_kdcs(TALLOC_CTX *ctx,
 824                             const char *dns_forest_name,
 825                             const char *sitename,
 826                             struct dns_rr_srv **dclist,
 827                             int *numdcs )
 828 {
 829         NTSTATUS status;
 830
 831         status = ads_dns_query_internal(ctx, "_kerberos", "dc",
 832                                         dns_forest_name, sitename, dclist,
 833                                         numdcs);
 834
 835         if (NT_STATUS_EQUAL(status, NT_STATUS_IO_TIMEOUT) ||
 836             NT_STATUS_EQUAL(status, NT_STATUS_CONNECTION_REFUSED)) {
 837                 return status;
 838         }
 839
 840         if (sitename &&
 841             ((!NT_STATUS_IS_OK(status)) ||
 842              (NT_STATUS_IS_OK(status) && (numdcs == 0)))) {
 843                 /* Sitename DNS query may have failed. Try without. */
 844                 status = ads_dns_query_internal(ctx, "_kerberos", "dc",
 845                                                 dns_forest_name, NULL,
 846                                                 dclist, numdcs);
 847         }
 848         return status;
 849 }
 850
 851 /********************************************************************
 852  Query for AD PDC. Sitename is obsolete here.
 853 ********************************************************************/
 854
 855 NTSTATUS ads_dns_query_pdc(TALLOC_CTX *ctx,
 856                            const char *dns_domain_name,
 857                            struct dns_rr_srv **dclist,
 858                            int *numdcs )
 859 {
 860         return ads_dns_query_internal(ctx, "_ldap", "pdc", dns_domain_name,
 861                                       NULL, dclist, numdcs);
 862 }
 863
 864 /********************************************************************
 865  Query for AD DC by guid. Sitename is obsolete here.
 866 ********************************************************************/
 867
 868 NTSTATUS ads_dns_query_dcs_guid(TALLOC_CTX *ctx,
 869                                 const char *dns_forest_name,
 870                                 const struct GUID *domain_guid,
 871                                 struct dns_rr_srv **dclist,
 872                                 int *numdcs )
 873 {
 874         /*_ldap._tcp.DomainGuid.domains._msdcs.DnsForestName */
 875
 876         const char *domains;
 877         char *guid_string;
 878
 879         guid_string = GUID_string(ctx, domain_guid);
 880         if (!guid_string) {
 881                 return NT_STATUS_NO_MEMORY;
 882         }
 883
 884         /* little hack */
 885         domains = talloc_asprintf(ctx, "%s.domains", guid_string);
 886         if (!domains) {
 887                 return NT_STATUS_NO_MEMORY;
 888         }
 889         TALLOC_FREE(guid_string);
 890
 891         return ads_dns_query_internal(ctx, "_ldap", domains, dns_forest_name,
 892                                       NULL, dclist, numdcs);
 893 }