source/libads/dns.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    DNS utility library
   4    Copyright (C) Gerald (Jerry) Carter           2006.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19 */
  20
  21 #include "includes.h"
  22
  23 /* AIX resolv.h uses 'class' in struct ns_rr */
  24
  25 #if defined(AIX)
  26 #  if defined(class)
  27 #    undef class
  28 #  endif
  29 #endif  /* AIX */
  30
  31 /* resolver headers */
  32
  33 #include <sys/types.h>
  34 #include <netinet/in.h>
  35 #include <arpa/nameser.h>
  36 #include <resolv.h>
  37 #include <netdb.h>
  38
  39 #define MAX_DNS_PACKET_SIZE 0xffff
  40
  41 #ifdef NS_HFIXEDSZ      /* Bind 8/9 interface */
  42 #if !defined(C_IN)      /* AIX 5.3 already defines C_IN */
  43 #  define C_IN          ns_c_in
  44 #endif
  45 #if !defined(T_A)       /* AIX 5.3 already defines T_A */
  46 #  define T_A           ns_t_a
  47 #endif
  48 #  define T_SRV         ns_t_srv
  49 #if !defined(T_NS)      /* AIX 5.3 already defines T_NS */
  50 #  define T_NS          ns_t_ns
  51 #endif
  52 #else
  53 #  ifdef HFIXEDSZ
  54 #    define NS_HFIXEDSZ HFIXEDSZ
  55 #  else
  56 #    define NS_HFIXEDSZ sizeof(HEADER)
  57 #  endif        /* HFIXEDSZ */
  58 #  ifdef PACKETSZ
  59 #    define NS_PACKETSZ PACKETSZ
  60 #  else /* 512 is usually the default */
  61 #    define NS_PACKETSZ 512
  62 #  endif        /* PACKETSZ */
  63 #  define T_SRV         33
  64 #endif
  65
  66 /*********************************************************************
  67 *********************************************************************/
  68
  69 static BOOL ads_dns_parse_query( TALLOC_CTX *ctx, uint8 *start, uint8 *end,
  70                           uint8 **ptr, struct dns_query *q )
  71 {
  72         uint8 *p = *ptr;
  73         pstring hostname;
  74         int namelen;
  75
  76         ZERO_STRUCTP( q );
  77
  78         if ( !start || !end || !q || !*ptr)
  79                 return False;
  80
  81         /* See RFC 1035 for details. If this fails, then return. */
  82
  83         namelen = dn_expand( start, end, p, hostname, sizeof(hostname) );
  84         if ( namelen < 0 ) {
  85                 return False;
  86         }
  87         p += namelen;
  88         q->hostname = talloc_strdup( ctx, hostname );
  89
  90         /* check that we have space remaining */
  91
  92         if ( PTR_DIFF(p+4, end) > 0 )
  93                 return False;
  94
  95         q->type     = RSVAL( p, 0 );
  96         q->in_class = RSVAL( p, 2 );
  97         p += 4;
  98
  99         *ptr = p;
 100
 101         return True;
 102 }
 103
 104 /*********************************************************************
 105 *********************************************************************/
 106
 107 static BOOL ads_dns_parse_rr( TALLOC_CTX *ctx, uint8 *start, uint8 *end,
 108                        uint8 **ptr, struct dns_rr *rr )
 109 {
 110         uint8 *p = *ptr;
 111         pstring hostname;
 112         int namelen;
 113
 114         if ( !start || !end || !rr || !*ptr)
 115                 return -1;
 116
 117         ZERO_STRUCTP( rr );
 118         /* pull the name from the answer */
 119
 120         namelen = dn_expand( start, end, p, hostname, sizeof(hostname) );
 121         if ( namelen < 0 ) {
 122                 return -1;
 123         }
 124         p += namelen;
 125         rr->hostname = talloc_strdup( ctx, hostname );
 126
 127         /* check that we have space remaining */
 128
 129         if ( PTR_DIFF(p+10, end) > 0 )
 130                 return False;
 131
 132         /* pull some values and then skip onto the string */
 133
 134         rr->type     = RSVAL(p, 0);
 135         rr->in_class = RSVAL(p, 2);
 136         rr->ttl      = RIVAL(p, 4);
 137         rr->rdatalen = RSVAL(p, 8);
 138
 139         p += 10;
 140
 141         /* sanity check the available space */
 142
 143         if ( PTR_DIFF(p+rr->rdatalen, end ) > 0 ) {
 144                 return False;
 145
 146         }
 147
 148         /* save a point to the rdata for this section */
 149
 150         rr->rdata = p;
 151         p += rr->rdatalen;
 152
 153         *ptr = p;
 154
 155         return True;
 156 }
 157
 158 /*********************************************************************
 159 *********************************************************************/
 160
 161 static BOOL ads_dns_parse_rr_srv( TALLOC_CTX *ctx, uint8 *start, uint8 *end,
 162                        uint8 **ptr, struct dns_rr_srv *srv )
 163 {
 164         struct dns_rr rr;
 165         uint8 *p;
 166         pstring dcname;
 167         int namelen;
 168
 169         if ( !start || !end || !srv || !*ptr)
 170                 return -1;
 171
 172         /* Parse the RR entry.  Coming out of the this, ptr is at the beginning
 173            of the next record */
 174
 175         if ( !ads_dns_parse_rr( ctx, start, end, ptr, &rr ) ) {
 176                 DEBUG(1,("ads_dns_parse_rr_srv: Failed to parse RR record\n"));
 177                 return False;
 178         }
 179
 180         if ( rr.type != T_SRV ) {
 181                 DEBUG(1,("ads_dns_parse_rr_srv: Bad answer type (%d)\n", rr.type));
 182                 return False;
 183         }
 184
 185         p = rr.rdata;
 186
 187         srv->priority = RSVAL(p, 0);
 188         srv->weight   = RSVAL(p, 2);
 189         srv->port     = RSVAL(p, 4);
 190
 191         p += 6;
 192
 193         namelen = dn_expand( start, end, p, dcname, sizeof(dcname) );
 194         if ( namelen < 0 ) {
 195                 DEBUG(1,("ads_dns_parse_rr_srv: Failed to uncompress name!\n"));
 196                 return False;
 197         }
 198         srv->hostname = talloc_strdup( ctx, dcname );
 199
 200         return True;
 201 }
 202
 203 /*********************************************************************
 204 *********************************************************************/
 205
 206 static BOOL ads_dns_parse_rr_ns( TALLOC_CTX *ctx, uint8 *start, uint8 *end,
 207                        uint8 **ptr, struct dns_rr_ns *nsrec )
 208 {
 209         struct dns_rr rr;
 210         uint8 *p;
 211         pstring nsname;
 212         int namelen;
 213
 214         if ( !start || !end || !nsrec || !*ptr)
 215                 return -1;
 216
 217         /* Parse the RR entry.  Coming out of the this, ptr is at the beginning
 218            of the next record */
 219
 220         if ( !ads_dns_parse_rr( ctx, start, end, ptr, &rr ) ) {
 221                 DEBUG(1,("ads_dns_parse_rr_ns: Failed to parse RR record\n"));
 222                 return False;
 223         }
 224
 225         if ( rr.type != T_NS ) {
 226                 DEBUG(1,("ads_dns_parse_rr_ns: Bad answer type (%d)\n", rr.type));
 227                 return False;
 228         }
 229
 230         p = rr.rdata;
 231
 232         /* ame server hostname */
 233
 234         namelen = dn_expand( start, end, p, nsname, sizeof(nsname) );
 235         if ( namelen < 0 ) {
 236                 DEBUG(1,("ads_dns_parse_rr_ns: Failed to uncompress name!\n"));
 237                 return False;
 238         }
 239         nsrec->hostname = talloc_strdup( ctx, nsname );
 240
 241         return True;
 242 }
 243
 244 /*********************************************************************
 245  Sort SRV record list based on weight and priority.  See RFC 2782.
 246 *********************************************************************/
 247
 248 static int dnssrvcmp( struct dns_rr_srv *a, struct dns_rr_srv *b )
 249 {
 250         if ( a->priority == b->priority ) {
 251
 252                 /* randomize entries with an equal weight and priority */
 253                 if ( a->weight == b->weight )
 254                         return 0;
 255
 256                 /* higher weights should be sorted lower */
 257                 if ( a->weight > b->weight )
 258                         return -1;
 259                 else
 260                         return 1;
 261         }
 262
 263         if ( a->priority < b->priority )
 264                 return -1;
 265
 266         return 1;
 267 }
 268
 269 /*********************************************************************
 270  Simple wrapper for a DNS query
 271 *********************************************************************/
 272
 273 #define DNS_FAILED_WAITTIME          30
 274
 275 static NTSTATUS dns_send_req( TALLOC_CTX *ctx, const char *name, int q_type,
 276                               uint8 **buf, int *resp_length )
 277 {
 278         uint8 *buffer = NULL;
 279         size_t buf_len;
 280         int resp_len = NS_PACKETSZ;
 281         static time_t last_dns_check = 0;
 282         static NTSTATUS last_dns_status = NT_STATUS_OK;
 283         time_t now = time(NULL);
 284
 285         /* Try to prevent bursts of DNS lookups if the server is down */
 286
 287         /* Protect against large clock changes */
 288
 289         if ( last_dns_check > now )
 290                 last_dns_check = 0;
 291
 292         /* IF we had a DNS timeout or a bad server and we are still
 293            in the 30 second cache window, just return the previous
 294            status and save the network timeout. */
 295
 296         if ( (NT_STATUS_EQUAL(last_dns_status,NT_STATUS_IO_TIMEOUT) ||
 297               NT_STATUS_EQUAL(last_dns_status,NT_STATUS_CONNECTION_REFUSED)) &&
 298              (last_dns_check+DNS_FAILED_WAITTIME) > now )
 299         {
 300                 DEBUG(10,("last_dns_check: Returning cached status (%s)\n",
 301                           nt_errstr(last_dns_status) ));
 302                 return last_dns_status;
 303         }
 304
 305         /* Send the Query */
 306         do {
 307                 if ( buffer )
 308                         TALLOC_FREE( buffer );
 309
 310                 buf_len = resp_len * sizeof(uint8);
 311
 312                 if (buf_len) {
 313                         if ( (buffer = TALLOC_ARRAY(ctx, uint8, buf_len)) == NULL ) {
 314                                 DEBUG(0,("ads_dns_lookup_srv: talloc() failed!\n"));
 315                                 last_dns_status = NT_STATUS_NO_MEMORY;
 316                                 last_dns_check = time(NULL);
 317                                 return last_dns_status;
 318                         }
 319                 }
 320
 321                 if ( (resp_len = res_query(name, C_IN, q_type, buffer, buf_len)) < 0 ) {
 322                         DEBUG(3,("ads_dns_lookup_srv: Failed to resolve %s (%s)\n", name, strerror(errno)));
 323                         TALLOC_FREE( buffer );
 324                         last_dns_status = NT_STATUS_UNSUCCESSFUL;
 325
 326                         if (errno == ETIMEDOUT) {
 327                                 last_dns_status = NT_STATUS_IO_TIMEOUT;
 328                         }
 329                         if (errno == ECONNREFUSED) {
 330                                 last_dns_status = NT_STATUS_CONNECTION_REFUSED;
 331                         }
 332                         last_dns_check = time(NULL);
 333                         return last_dns_status;
 334                 }
 335         } while ( buf_len < resp_len && resp_len < MAX_DNS_PACKET_SIZE );
 336
 337         *buf = buffer;
 338         *resp_length = resp_len;
 339
 340         last_dns_check = time(NULL);
 341         last_dns_status = NT_STATUS_OK;
 342         return last_dns_status;
 343 }
 344
 345 /*********************************************************************
 346  Simple wrapper for a DNS SRV query
 347 *********************************************************************/
 348
 349 static NTSTATUS ads_dns_lookup_srv( TALLOC_CTX *ctx, const char *name, struct dns_rr_srv **dclist, int *numdcs )
 350 {
 351         uint8 *buffer = NULL;
 352         int resp_len = 0;
 353         struct dns_rr_srv *dcs = NULL;
 354         int query_count, answer_count, auth_count, additional_count;
 355         uint8 *p = buffer;
 356         int rrnum;
 357         int idx = 0;
 358         NTSTATUS status;
 359
 360         if ( !ctx || !name || !dclist ) {
 361                 return NT_STATUS_INVALID_PARAMETER;
 362         }
 363
 364         /* Send the request.  May have to loop several times in case
 365            of large replies */
 366
 367         status = dns_send_req( ctx, name, T_SRV, &buffer, &resp_len );
 368         if ( !NT_STATUS_IS_OK(status) ) {
 369                 DEBUG(3,("ads_dns_lookup_srv: Failed to send DNS query (%s)\n",
 370                         nt_errstr(status)));
 371                 return status;
 372         }
 373         p = buffer;
 374
 375         /* For some insane reason, the ns_initparse() et. al. routines are only
 376            available in libresolv.a, and not the shared lib.  Who knows why....
 377            So we have to parse the DNS reply ourselves */
 378
 379         /* Pull the answer RR's count from the header.  Use the NMB ordering macros */
 380
 381         query_count      = RSVAL( p, 4 );
 382         answer_count     = RSVAL( p, 6 );
 383         auth_count       = RSVAL( p, 8 );
 384         additional_count = RSVAL( p, 10 );
 385
 386         DEBUG(4,("ads_dns_lookup_srv: %d records returned in the answer section.\n",
 387                 answer_count));
 388
 389         if (answer_count) {
 390                 if ( (dcs = TALLOC_ZERO_ARRAY(ctx, struct dns_rr_srv, answer_count)) == NULL ) {
 391                         DEBUG(0,("ads_dns_lookup_srv: talloc() failure for %d char*'s\n",
 392                                 answer_count));
 393                         return NT_STATUS_NO_MEMORY;
 394                 }
 395         } else {
 396                 dcs = NULL;
 397         }
 398
 399         /* now skip the header */
 400
 401         p += NS_HFIXEDSZ;
 402
 403         /* parse the query section */
 404
 405         for ( rrnum=0; rrnum<query_count; rrnum++ ) {
 406                 struct dns_query q;
 407
 408                 if ( !ads_dns_parse_query( ctx, buffer, buffer+resp_len, &p, &q ) ) {
 409                         DEBUG(1,("ads_dns_lookup_srv: Failed to parse query record!\n"));
 410                         return NT_STATUS_UNSUCCESSFUL;
 411                 }
 412         }
 413
 414         /* now we are at the answer section */
 415
 416         for ( rrnum=0; rrnum<answer_count; rrnum++ ) {
 417                 if ( !ads_dns_parse_rr_srv( ctx, buffer, buffer+resp_len, &p, &dcs[rrnum] ) ) {
 418                         DEBUG(1,("ads_dns_lookup_srv: Failed to parse answer record!\n"));
 419                         return NT_STATUS_UNSUCCESSFUL;
 420                 }
 421         }
 422         idx = rrnum;
 423
 424         /* Parse the authority section */
 425         /* just skip these for now */
 426
 427         for ( rrnum=0; rrnum<auth_count; rrnum++ ) {
 428                 struct dns_rr rr;
 429
 430                 if ( !ads_dns_parse_rr( ctx, buffer, buffer+resp_len, &p, &rr ) ) {
 431                         DEBUG(1,("ads_dns_lookup_srv: Failed to parse authority record!\n"));
 432                         return NT_STATUS_UNSUCCESSFUL;
 433                 }
 434         }
 435
 436         /* Parse the additional records section */
 437
 438         for ( rrnum=0; rrnum<additional_count; rrnum++ ) {
 439                 struct dns_rr rr;
 440                 int i;
 441
 442                 if ( !ads_dns_parse_rr( ctx, buffer, buffer+resp_len, &p, &rr ) ) {
 443                         DEBUG(1,("ads_dns_lookup_srv: Failed to parse additional records section!\n"));
 444                         return NT_STATUS_UNSUCCESSFUL;
 445                 }
 446
 447                 /* only interested in A records as a shortcut for having to come
 448                    back later and lookup the name.  For multi-homed hosts, the
 449                    number of additional records and exceed the number of answer
 450                    records. */
 451
 452
 453                 if ( (rr.type != T_A) || (rr.rdatalen != 4) )
 454                         continue;
 455
 456                 for ( i=0; i<idx; i++ ) {
 457                         if ( strcmp( rr.hostname, dcs[i].hostname ) == 0 ) {
 458                                 int num_ips = dcs[i].num_ips;
 459                                 uint8 *buf;
 460                                 struct in_addr *tmp_ips;
 461
 462                                 /* allocate new memory */
 463
 464                                 if ( dcs[i].num_ips == 0 ) {
 465                                         if ( (dcs[i].ips = TALLOC_ARRAY( dcs,
 466                                                 struct in_addr, 1 )) == NULL )
 467                                         {
 468                                                 return NT_STATUS_NO_MEMORY;
 469                                         }
 470                                 } else {
 471                                         if ( (tmp_ips = TALLOC_REALLOC_ARRAY( dcs, dcs[i].ips,
 472                                                 struct in_addr, dcs[i].num_ips+1)) == NULL )
 473                                         {
 474                                                 return NT_STATUS_NO_MEMORY;
 475                                         }
 476
 477                                         dcs[i].ips = tmp_ips;
 478                                 }
 479                                 dcs[i].num_ips++;
 480
 481                                 /* copy the new IP address */
 482
 483                                 buf = (uint8*)&dcs[i].ips[num_ips].s_addr;
 484                                 memcpy( buf, rr.rdata, 4 );
 485                         }
 486                 }
 487         }
 488
 489         qsort( dcs, idx, sizeof(struct dns_rr_srv), QSORT_CAST dnssrvcmp );
 490
 491         *dclist = dcs;
 492         *numdcs = idx;
 493
 494         return NT_STATUS_OK;
 495 }
 496
 497 /*********************************************************************
 498  Simple wrapper for a DNS NS query
 499 *********************************************************************/
 500
 501 NTSTATUS ads_dns_lookup_ns( TALLOC_CTX *ctx, const char *dnsdomain, struct dns_rr_ns **nslist, int *numns )
 502 {
 503         uint8 *buffer = NULL;
 504         int resp_len = 0;
 505         struct dns_rr_ns *nsarray = NULL;
 506         int query_count, answer_count, auth_count, additional_count;
 507         uint8 *p;
 508         int rrnum;
 509         int idx = 0;
 510         NTSTATUS status;
 511
 512         if ( !ctx || !dnsdomain || !nslist ) {
 513                 return NT_STATUS_INVALID_PARAMETER;
 514         }
 515
 516         /* Send the request.  May have to loop several times in case
 517            of large replies */
 518
 519         status = dns_send_req( ctx, dnsdomain, T_NS, &buffer, &resp_len );
 520         if ( !NT_STATUS_IS_OK(status) ) {
 521                 DEBUG(3,("ads_dns_lookup_ns: Failed to send DNS query (%s)\n",
 522                         nt_errstr(status)));
 523                 return status;
 524         }
 525         p = buffer;
 526
 527         /* For some insane reason, the ns_initparse() et. al. routines are only
 528            available in libresolv.a, and not the shared lib.  Who knows why....
 529            So we have to parse the DNS reply ourselves */
 530
 531         /* Pull the answer RR's count from the header.  Use the NMB ordering macros */
 532
 533         query_count      = RSVAL( p, 4 );
 534         answer_count     = RSVAL( p, 6 );
 535         auth_count       = RSVAL( p, 8 );
 536         additional_count = RSVAL( p, 10 );
 537
 538         DEBUG(4,("ads_dns_lookup_ns: %d records returned in the answer section.\n",
 539                 answer_count));
 540
 541         if (answer_count) {
 542                 if ( (nsarray = TALLOC_ARRAY(ctx, struct dns_rr_ns, answer_count)) == NULL ) {
 543                         DEBUG(0,("ads_dns_lookup_ns: talloc() failure for %d char*'s\n",
 544                                 answer_count));
 545                         return NT_STATUS_NO_MEMORY;
 546                 }
 547         } else {
 548                 nsarray = NULL;
 549         }
 550
 551         /* now skip the header */
 552
 553         p += NS_HFIXEDSZ;
 554
 555         /* parse the query section */
 556
 557         for ( rrnum=0; rrnum<query_count; rrnum++ ) {
 558                 struct dns_query q;
 559
 560                 if ( !ads_dns_parse_query( ctx, buffer, buffer+resp_len, &p, &q ) ) {
 561                         DEBUG(1,("ads_dns_lookup_ns: Failed to parse query record!\n"));
 562                         return NT_STATUS_UNSUCCESSFUL;
 563                 }
 564         }
 565
 566         /* now we are at the answer section */
 567
 568         for ( rrnum=0; rrnum<answer_count; rrnum++ ) {
 569                 if ( !ads_dns_parse_rr_ns( ctx, buffer, buffer+resp_len, &p, &nsarray[rrnum] ) ) {
 570                         DEBUG(1,("ads_dns_lookup_ns: Failed to parse answer record!\n"));
 571                         return NT_STATUS_UNSUCCESSFUL;
 572                 }
 573         }
 574         idx = rrnum;
 575
 576         /* Parse the authority section */
 577         /* just skip these for now */
 578
 579         for ( rrnum=0; rrnum<auth_count; rrnum++ ) {
 580                 struct dns_rr rr;
 581
 582                 if ( !ads_dns_parse_rr( ctx, buffer, buffer+resp_len, &p, &rr ) ) {
 583                         DEBUG(1,("ads_dns_lookup_ns: Failed to parse authority record!\n"));
 584                         return NT_STATUS_UNSUCCESSFUL;
 585                 }
 586         }
 587
 588         /* Parse the additional records section */
 589
 590         for ( rrnum=0; rrnum<additional_count; rrnum++ ) {
 591                 struct dns_rr rr;
 592                 int i;
 593
 594                 if ( !ads_dns_parse_rr( ctx, buffer, buffer+resp_len, &p, &rr ) ) {
 595                         DEBUG(1,("ads_dns_lookup_ns: Failed to parse additional records section!\n"));
 596                         return NT_STATUS_UNSUCCESSFUL;
 597                 }
 598
 599                 /* only interested in A records as a shortcut for having to come
 600                    back later and lookup the name */
 601
 602                 if ( (rr.type != T_A) || (rr.rdatalen != 4) )
 603                         continue;
 604
 605                 for ( i=0; i<idx; i++ ) {
 606                         if ( strcmp( rr.hostname, nsarray[i].hostname ) == 0 ) {
 607                                 uint8 *buf = (uint8*)&nsarray[i].ip.s_addr;
 608                                 memcpy( buf, rr.rdata, 4 );
 609                         }
 610                 }
 611         }
 612
 613         *nslist = nsarray;
 614         *numns = idx;
 615
 616         return NT_STATUS_OK;
 617 }
 618
 619 /****************************************************************************
 620  Store and fetch the AD client sitename.
 621 ****************************************************************************/
 622
 623 #define SITENAME_KEY    "AD_SITENAME/DOMAIN/%s"
 624
 625 static char *sitename_key(const char *realm)
 626 {
 627         char *keystr;
 628
 629         if (asprintf(&keystr, SITENAME_KEY, strupper_static(realm)) == -1) {
 630                 return NULL;
 631         }
 632
 633         return keystr;
 634 }
 635
 636
 637 /****************************************************************************
 638  Store the AD client sitename.
 639  We store indefinately as every new CLDAP query will re-write this.
 640  If the sitename is "Default-First-Site-Name" we don't store it
 641  as this isn't a valid DNS name.
 642 ****************************************************************************/
 643
 644 BOOL sitename_store(const char *realm, const char *sitename)
 645 {
 646         time_t expire;
 647         BOOL ret = False;
 648         char *key;
 649
 650         if (!gencache_init()) {
 651                 return False;
 652         }
 653
 654         if (!realm || (strlen(realm) == 0)) {
 655                 DEBUG(0,("no realm\n"));
 656                 return False;
 657         }
 658
 659         key = sitename_key(realm);
 660
 661         if (!sitename || (sitename && !*sitename)) {
 662                 DEBUG(5,("sitename_store: deleting empty sitename!\n"));
 663                 ret = gencache_del(key);
 664                 SAFE_FREE(key);
 665                 return ret;
 666         }
 667
 668         expire = get_time_t_max(); /* Store indefinately. */
 669
 670         DEBUG(10,("sitename_store: realm = [%s], sitename = [%s], expire = [%u]\n",
 671                 realm, sitename, (unsigned int)expire ));
 672
 673         ret = gencache_set( key, sitename, expire );
 674         SAFE_FREE(key);
 675         return ret;
 676 }
 677
 678 /****************************************************************************
 679  Fetch the AD client sitename.
 680  Caller must free.
 681 ****************************************************************************/
 682
 683 char *sitename_fetch(const char *realm)
 684 {
 685         char *sitename = NULL;
 686         time_t timeout;
 687         BOOL ret = False;
 688         const char *query_realm;
 689         char *key;
 690
 691         if (!gencache_init()) {
 692                 return False;
 693         }
 694
 695         if (!realm || (strlen(realm) == 0)) {
 696                 query_realm = lp_realm();
 697         } else {
 698                 query_realm = realm;
 699         }
 700
 701         key = sitename_key(query_realm);
 702
 703         ret = gencache_get( key, &sitename, &timeout );
 704         SAFE_FREE(key);
 705         if ( !ret ) {
 706                 DEBUG(5,("sitename_fetch: No stored sitename for %s\n",
 707                         query_realm));
 708         } else {
 709                 DEBUG(5,("sitename_fetch: Returning sitename for %s: \"%s\"\n",
 710                         query_realm, sitename ));
 711         }
 712         return sitename;
 713 }
 714
 715 /****************************************************************************
 716  Did the sitename change ?
 717 ****************************************************************************/
 718
 719 BOOL stored_sitename_changed(const char *realm, const char *sitename)
 720 {
 721         BOOL ret = False;
 722
 723         char *new_sitename;
 724
 725         if (!realm || (strlen(realm) == 0)) {
 726                 DEBUG(0,("no realm\n"));
 727                 return False;
 728         }
 729
 730         new_sitename = sitename_fetch(realm);
 731
 732         if (sitename && new_sitename && !strequal(sitename, new_sitename)) {
 733                 ret = True;
 734         } else if ((sitename && !new_sitename) ||
 735                         (!sitename && new_sitename)) {
 736                 ret = True;
 737         }
 738         SAFE_FREE(new_sitename);
 739         return ret;
 740 }
 741
 742 /********************************************************************
 743  Query with optional sitename.
 744 ********************************************************************/
 745
 746 NTSTATUS ads_dns_query_internal(TALLOC_CTX *ctx,
 747                                 const char *servicename,
 748                                 const char *realm,
 749                                 const char *sitename,
 750                                 struct dns_rr_srv **dclist,
 751                                 int *numdcs )
 752 {
 753         char *name;
 754         if (sitename) {
 755                 name = talloc_asprintf(ctx, "%s._tcp.%s._sites.dc._msdcs.%s",
 756                                 servicename, sitename, realm );
 757         } else {
 758                 name = talloc_asprintf(ctx, "%s._tcp.dc._msdcs.%s",
 759                                 servicename, realm );
 760         }
 761         if (!name) {
 762                 return NT_STATUS_NO_MEMORY;
 763         }
 764         return ads_dns_lookup_srv( ctx, name, dclist, numdcs );
 765 }
 766
 767 /********************************************************************
 768  Query for AD DC's.
 769 ********************************************************************/
 770
 771 NTSTATUS ads_dns_query_dcs(TALLOC_CTX *ctx,
 772                         const char *realm,
 773                         const char *sitename,
 774                         struct dns_rr_srv **dclist,
 775                         int *numdcs )
 776 {
 777         NTSTATUS status;
 778
 779         status = ads_dns_query_internal(ctx, "_ldap", realm, sitename,
 780                                         dclist, numdcs);
 781
 782         if (NT_STATUS_EQUAL(status, NT_STATUS_IO_TIMEOUT) ||
 783             NT_STATUS_EQUAL(status, NT_STATUS_CONNECTION_REFUSED)) {
 784                 return status;
 785         }
 786
 787         if (sitename && !NT_STATUS_IS_OK(status)) {
 788                 /* Sitename DNS query may have failed. Try without. */
 789                 status = ads_dns_query_internal(ctx, "_ldap", realm, NULL,
 790                                                 dclist, numdcs);
 791         }
 792         return status;
 793 }
 794
 795 /********************************************************************
 796  Query for AD KDC's.
 797  Even if our underlying kerberos libraries are UDP only, this
 798  is pretty safe as it's unlikely that a KDC supports TCP and not UDP.
 799 ********************************************************************/
 800
 801 NTSTATUS ads_dns_query_kdcs(TALLOC_CTX *ctx,
 802                         const char *realm,
 803                         const char *sitename,
 804                         struct dns_rr_srv **dclist,
 805                         int *numdcs )
 806 {
 807         NTSTATUS status;
 808
 809         status = ads_dns_query_internal(ctx, "_kerberos", realm, sitename,
 810                                         dclist, numdcs);
 811
 812         if (NT_STATUS_EQUAL(status, NT_STATUS_IO_TIMEOUT) ||
 813             NT_STATUS_EQUAL(status, NT_STATUS_CONNECTION_REFUSED)) {
 814                 return status;
 815         }
 816
 817         if (sitename && !NT_STATUS_IS_OK(status)) {
 818                 /* Sitename DNS query may have failed. Try without. */
 819                 status = ads_dns_query_internal(ctx, "_kerberos", realm, NULL,
 820                                                 dclist, numdcs);
 821         }
 822         return status;
 823 }