source: trunk/samba/source/libads/dns.c@ 77

Last change on this file since 77 was 77, checked in by Paul Smedley, 18 years ago

Update trunk to 3.2.0pre1
File size: 24.0 KB
Line 
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 3 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, see <http://www.gnu.org/licenses/>.
18*/
19
20#include "includes.h"
21
22/* AIX resolv.h uses 'class' in struct ns_rr */
23
24#if defined(AIX)
25# if defined(class)
26# undef class
27# endif
28#endif /* AIX */
29
30/* resolver headers */
31
32#include <sys/types.h>
33#include <netinet/in.h>
34#include <arpa/nameser.h>
35#include <resolv.h>
36#include <netdb.h>
37
38#define MAX_DNS_PACKET_SIZE 0xffff
39
40#ifdef NS_HFIXEDSZ /* Bind 8/9 interface */
41#if !defined(C_IN) /* AIX 5.3 already defines C_IN */
42# define C_IN ns_c_in
43#endif
44#if !defined(T_A) /* AIX 5.3 already defines T_A */
45# define T_A ns_t_a
46#endif
47# define T_SRV ns_t_srv
48#if !defined(T_NS) /* AIX 5.3 already defines T_NS */
49# define T_NS ns_t_ns
50#endif
51#else
52# ifdef HFIXEDSZ
53# define NS_HFIXEDSZ HFIXEDSZ
54# else
55# define NS_HFIXEDSZ sizeof(HEADER)
56# endif /* HFIXEDSZ */
57# ifdef PACKETSZ
58# define NS_PACKETSZ PACKETSZ
59# else /* 512 is usually the default */
60# define NS_PACKETSZ 512
61# endif /* PACKETSZ */
62# define T_SRV 33
63#endif
64
65/*********************************************************************
66*********************************************************************/
67
68static BOOL ads_dns_parse_query( TALLOC_CTX *ctx, uint8 *start, uint8 *end,
69 uint8 **ptr, struct dns_query *q )
70{
71 uint8 *p = *ptr;
72 pstring hostname;
73 int namelen;
74
75 ZERO_STRUCTP( q );
76
77 if ( !start || !end || !q || !*ptr)
78 return False;
79
80 /* See RFC 1035 for details. If this fails, then return. */
81
82 namelen = dn_expand( start, end, p, hostname, sizeof(hostname) );
83 if ( namelen < 0 ) {
84 return False;
85 }
86 p += namelen;
87 q->hostname = talloc_strdup( ctx, hostname );
88
89 /* check that we have space remaining */
90
91 if ( PTR_DIFF(p+4, end) > 0 )
92 return False;
93
94 q->type = RSVAL( p, 0 );
95 q->in_class = RSVAL( p, 2 );
96 p += 4;
97
98 *ptr = p;
99
100 return True;
101}
102
103/*********************************************************************
104*********************************************************************/
105
106static BOOL ads_dns_parse_rr( TALLOC_CTX *ctx, uint8 *start, uint8 *end,
107 uint8 **ptr, struct dns_rr *rr )
108{
109 uint8 *p = *ptr;
110 pstring hostname;
111 int namelen;
112
113 if ( !start || !end || !rr || !*ptr)
114 return -1;
115
116 ZERO_STRUCTP( rr );
117 /* pull the name from the answer */
118
119 namelen = dn_expand( start, end, p, hostname, sizeof(hostname) );
120 if ( namelen < 0 ) {
121 return -1;
122 }
123 p += namelen;
124 rr->hostname = talloc_strdup( ctx, hostname );
125
126 /* check that we have space remaining */
127
128 if ( PTR_DIFF(p+10, end) > 0 )
129 return False;
130
131 /* pull some values and then skip onto the string */
132
133 rr->type = RSVAL(p, 0);
134 rr->in_class = RSVAL(p, 2);
135 rr->ttl = RIVAL(p, 4);
136 rr->rdatalen = RSVAL(p, 8);
137
138 p += 10;
139
140 /* sanity check the available space */
141
142 if ( PTR_DIFF(p+rr->rdatalen, end ) > 0 ) {
143 return False;
144
145 }
146
147 /* save a point to the rdata for this section */
148
149 rr->rdata = p;
150 p += rr->rdatalen;
151
152 *ptr = p;
153
154 return True;
155}
156
157/*********************************************************************
158*********************************************************************/
159
160static BOOL ads_dns_parse_rr_srv( TALLOC_CTX *ctx, uint8 *start, uint8 *end,
161 uint8 **ptr, struct dns_rr_srv *srv )
162{
163 struct dns_rr rr;
164 uint8 *p;
165 pstring dcname;
166 int namelen;
167
168 if ( !start || !end || !srv || !*ptr)
169 return -1;
170
171 /* Parse the RR entry. Coming out of the this, ptr is at the beginning
172 of the next record */
173
174 if ( !ads_dns_parse_rr( ctx, start, end, ptr, &rr ) ) {
175 DEBUG(1,("ads_dns_parse_rr_srv: Failed to parse RR record\n"));
176 return False;
177 }
178
179 if ( rr.type != T_SRV ) {
180 DEBUG(1,("ads_dns_parse_rr_srv: Bad answer type (%d)\n", rr.type));
181 return False;
182 }
183
184 p = rr.rdata;
185
186 srv->priority = RSVAL(p, 0);
187 srv->weight = RSVAL(p, 2);
188 srv->port = RSVAL(p, 4);
189
190 p += 6;
191
192 namelen = dn_expand( start, end, p, dcname, sizeof(dcname) );
193 if ( namelen < 0 ) {
194 DEBUG(1,("ads_dns_parse_rr_srv: Failed to uncompress name!\n"));
195 return False;
196 }
197 srv->hostname = talloc_strdup( ctx, dcname );
198
199 return True;
200}
201
202/*********************************************************************
203*********************************************************************/
204
205static BOOL ads_dns_parse_rr_ns( TALLOC_CTX *ctx, uint8 *start, uint8 *end,
206 uint8 **ptr, struct dns_rr_ns *nsrec )
207{
208 struct dns_rr rr;
209 uint8 *p;
210 pstring nsname;
211 int namelen;
212
213 if ( !start || !end || !nsrec || !*ptr)
214 return -1;
215
216 /* Parse the RR entry. Coming out of the this, ptr is at the beginning
217 of the next record */
218
219 if ( !ads_dns_parse_rr( ctx, start, end, ptr, &rr ) ) {
220 DEBUG(1,("ads_dns_parse_rr_ns: Failed to parse RR record\n"));
221 return False;
222 }
223
224 if ( rr.type != T_NS ) {
225 DEBUG(1,("ads_dns_parse_rr_ns: Bad answer type (%d)\n", rr.type));
226 return False;
227 }
228
229 p = rr.rdata;
230
231 /* ame server hostname */
232
233 namelen = dn_expand( start, end, p, nsname, sizeof(nsname) );
234 if ( namelen < 0 ) {
235 DEBUG(1,("ads_dns_parse_rr_ns: Failed to uncompress name!\n"));
236 return False;
237 }
238 nsrec->hostname = talloc_strdup( ctx, nsname );
239
240 return True;
241}
242
243/*********************************************************************
244 Sort SRV record list based on weight and priority. See RFC 2782.
245*********************************************************************/
246
247static int dnssrvcmp( struct dns_rr_srv *a, struct dns_rr_srv *b )
248{
249 if ( a->priority == b->priority ) {
250
251 /* randomize entries with an equal weight and priority */
252 if ( a->weight == b->weight )
253 return 0;
254
255 /* higher weights should be sorted lower */
256 if ( a->weight > b->weight )
257 return -1;
258 else
259 return 1;
260 }
261
262 if ( a->priority < b->priority )
263 return -1;
264
265 return 1;
266}
267
268/*********************************************************************
269 Simple wrapper for a DNS query
270*********************************************************************/
271
272#define DNS_FAILED_WAITTIME 30
273
274static NTSTATUS dns_send_req( TALLOC_CTX *ctx, const char *name, int q_type,
275 uint8 **buf, int *resp_length )
276{
277 uint8 *buffer = NULL;
278 size_t buf_len;
279 int resp_len = NS_PACKETSZ;
280 static time_t last_dns_check = 0;
281 static NTSTATUS last_dns_status = NT_STATUS_OK;
282 time_t now = time(NULL);
283
284 /* Try to prevent bursts of DNS lookups if the server is down */
285
286 /* Protect against large clock changes */
287
288 if ( last_dns_check > now )
289 last_dns_check = 0;
290
291 /* IF we had a DNS timeout or a bad server and we are still
292 in the 30 second cache window, just return the previous
293 status and save the network timeout. */
294
295 if ( (NT_STATUS_EQUAL(last_dns_status,NT_STATUS_IO_TIMEOUT) ||
296 NT_STATUS_EQUAL(last_dns_status,NT_STATUS_CONNECTION_REFUSED)) &&
297 (last_dns_check+DNS_FAILED_WAITTIME) > now )
298 {
299 DEBUG(10,("last_dns_check: Returning cached status (%s)\n",
300 nt_errstr(last_dns_status) ));
301 return last_dns_status;
302 }
303
304 /* Send the Query */
305 do {
306 if ( buffer )
307 TALLOC_FREE( buffer );
308
309 buf_len = resp_len * sizeof(uint8);
310
311 if (buf_len) {
312 if ( (buffer = TALLOC_ARRAY(ctx, uint8, buf_len)) == NULL ) {
313 DEBUG(0,("ads_dns_lookup_srv: talloc() failed!\n"));
314 last_dns_status = NT_STATUS_NO_MEMORY;
315 last_dns_check = time(NULL);
316 return last_dns_status;
317 }
318 }
319
320 if ( (resp_len = res_query(name, C_IN, q_type, buffer, buf_len)) < 0 ) {
321 DEBUG(3,("ads_dns_lookup_srv: Failed to resolve %s (%s)\n", name, strerror(errno)));
322 TALLOC_FREE( buffer );
323 last_dns_status = NT_STATUS_UNSUCCESSFUL;
324
325 if (errno == ETIMEDOUT) {
326 last_dns_status = NT_STATUS_IO_TIMEOUT;
327 }
328 if (errno == ECONNREFUSED) {
329 last_dns_status = NT_STATUS_CONNECTION_REFUSED;
330 }
331 last_dns_check = time(NULL);
332 return last_dns_status;
333 }
334 } while ( buf_len < resp_len && resp_len < MAX_DNS_PACKET_SIZE );
335
336 *buf = buffer;
337 *resp_length = resp_len;
338
339 last_dns_check = time(NULL);
340 last_dns_status = NT_STATUS_OK;
341 return last_dns_status;
342}
343
344/*********************************************************************
345 Simple wrapper for a DNS SRV query
346*********************************************************************/
347
348static NTSTATUS ads_dns_lookup_srv( TALLOC_CTX *ctx, const char *name, struct dns_rr_srv **dclist, int *numdcs )
349{
350 uint8 *buffer = NULL;
351 int resp_len = 0;
352 struct dns_rr_srv *dcs = NULL;
353 int query_count, answer_count, auth_count, additional_count;
354 uint8 *p = buffer;
355 int rrnum;
356 int idx = 0;
357 NTSTATUS status;
358
359 if ( !ctx || !name || !dclist ) {
360 return NT_STATUS_INVALID_PARAMETER;
361 }
362
363 /* Send the request. May have to loop several times in case
364 of large replies */
365
366 status = dns_send_req( ctx, name, T_SRV, &buffer, &resp_len );
367 if ( !NT_STATUS_IS_OK(status) ) {
368 DEBUG(3,("ads_dns_lookup_srv: Failed to send DNS query (%s)\n",
369 nt_errstr(status)));
370 return status;
371 }
372 p = buffer;
373
374 /* For some insane reason, the ns_initparse() et. al. routines are only
375 available in libresolv.a, and not the shared lib. Who knows why....
376 So we have to parse the DNS reply ourselves */
377
378 /* Pull the answer RR's count from the header. Use the NMB ordering macros */
379
380 query_count = RSVAL( p, 4 );
381 answer_count = RSVAL( p, 6 );
382 auth_count = RSVAL( p, 8 );
383 additional_count = RSVAL( p, 10 );
384
385 DEBUG(4,("ads_dns_lookup_srv: %d records returned in the answer section.\n",
386 answer_count));
387
388 if (answer_count) {
389 if ( (dcs = TALLOC_ZERO_ARRAY(ctx, struct dns_rr_srv, answer_count)) == NULL ) {
390 DEBUG(0,("ads_dns_lookup_srv: talloc() failure for %d char*'s\n",
391 answer_count));
392 return NT_STATUS_NO_MEMORY;
393 }
394 } else {
395 dcs = NULL;
396 }
397
398 /* now skip the header */
399
400 p += NS_HFIXEDSZ;
401
402 /* parse the query section */
403
404 for ( rrnum=0; rrnum<query_count; rrnum++ ) {
405 struct dns_query q;
406
407 if ( !ads_dns_parse_query( ctx, buffer, buffer+resp_len, &p, &q ) ) {
408 DEBUG(1,("ads_dns_lookup_srv: Failed to parse query record!\n"));
409 return NT_STATUS_UNSUCCESSFUL;
410 }
411 }
412
413 /* now we are at the answer section */
414
415 for ( rrnum=0; rrnum<answer_count; rrnum++ ) {
416 if ( !ads_dns_parse_rr_srv( ctx, buffer, buffer+resp_len, &p, &dcs[rrnum] ) ) {
417 DEBUG(1,("ads_dns_lookup_srv: Failed to parse answer record!\n"));
418 return NT_STATUS_UNSUCCESSFUL;
419 }
420 }
421 idx = rrnum;
422
423 /* Parse the authority section */
424 /* just skip these for now */
425
426 for ( rrnum=0; rrnum<auth_count; rrnum++ ) {
427 struct dns_rr rr;
428
429 if ( !ads_dns_parse_rr( ctx, buffer, buffer+resp_len, &p, &rr ) ) {
430 DEBUG(1,("ads_dns_lookup_srv: Failed to parse authority record!\n"));
431 return NT_STATUS_UNSUCCESSFUL;
432 }
433 }
434
435 /* Parse the additional records section */
436
437 for ( rrnum=0; rrnum<additional_count; rrnum++ ) {
438 struct dns_rr rr;
439 int i;
440
441 if ( !ads_dns_parse_rr( ctx, buffer, buffer+resp_len, &p, &rr ) ) {
442 DEBUG(1,("ads_dns_lookup_srv: Failed to parse additional records section!\n"));
443 return NT_STATUS_UNSUCCESSFUL;
444 }
445
446 /* only interested in A records as a shortcut for having to come
447 back later and lookup the name. For multi-homed hosts, the
448 number of additional records and exceed the number of answer
449 records. */
450
451
452 if ( (rr.type != T_A) || (rr.rdatalen != 4) )
453 continue;
454
455 for ( i=0; i<idx; i++ ) {
456 if ( strcmp( rr.hostname, dcs[i].hostname ) == 0 ) {
457 int num_ips = dcs[i].num_ips;
458 uint8 *buf;
459 struct in_addr *tmp_ips;
460
461 /* allocate new memory */
462
463 if ( dcs[i].num_ips == 0 ) {
464 if ( (dcs[i].ips = TALLOC_ARRAY( dcs,
465 struct in_addr, 1 )) == NULL )
466 {
467 return NT_STATUS_NO_MEMORY;
468 }
469 } else {
470 if ( (tmp_ips = TALLOC_REALLOC_ARRAY( dcs, dcs[i].ips,
471 struct in_addr, dcs[i].num_ips+1)) == NULL )
472 {
473 return NT_STATUS_NO_MEMORY;
474 }
475
476 dcs[i].ips = tmp_ips;
477 }
478 dcs[i].num_ips++;
479
480 /* copy the new IP address */
481
482 buf = (uint8*)&dcs[i].ips[num_ips].s_addr;
483 memcpy( buf, rr.rdata, 4 );
484 }
485 }
486 }
487
488 qsort( dcs, idx, sizeof(struct dns_rr_srv), QSORT_CAST dnssrvcmp );
489
490 *dclist = dcs;
491 *numdcs = idx;
492
493 return NT_STATUS_OK;
494}
495
496/*********************************************************************
497 Simple wrapper for a DNS NS query
498*********************************************************************/
499
500NTSTATUS ads_dns_lookup_ns( TALLOC_CTX *ctx, const char *dnsdomain, struct dns_rr_ns **nslist, int *numns )
501{
502 uint8 *buffer = NULL;
503 int resp_len = 0;
504 struct dns_rr_ns *nsarray = NULL;
505 int query_count, answer_count, auth_count, additional_count;
506 uint8 *p;
507 int rrnum;
508 int idx = 0;
509 NTSTATUS status;
510
511 if ( !ctx || !dnsdomain || !nslist ) {
512 return NT_STATUS_INVALID_PARAMETER;
513 }
514
515 /* Send the request. May have to loop several times in case
516 of large replies */
517
518 status = dns_send_req( ctx, dnsdomain, T_NS, &buffer, &resp_len );
519 if ( !NT_STATUS_IS_OK(status) ) {
520 DEBUG(3,("ads_dns_lookup_ns: Failed to send DNS query (%s)\n",
521 nt_errstr(status)));
522 return status;
523 }
524 p = buffer;
525
526 /* For some insane reason, the ns_initparse() et. al. routines are only
527 available in libresolv.a, and not the shared lib. Who knows why....
528 So we have to parse the DNS reply ourselves */
529
530 /* Pull the answer RR's count from the header. Use the NMB ordering macros */
531
532 query_count = RSVAL( p, 4 );
533 answer_count = RSVAL( p, 6 );
534 auth_count = RSVAL( p, 8 );
535 additional_count = RSVAL( p, 10 );
536
537 DEBUG(4,("ads_dns_lookup_ns: %d records returned in the answer section.\n",
538 answer_count));
539
540 if (answer_count) {
541 if ( (nsarray = TALLOC_ARRAY(ctx, struct dns_rr_ns, answer_count)) == NULL ) {
542 DEBUG(0,("ads_dns_lookup_ns: talloc() failure for %d char*'s\n",
543 answer_count));
544 return NT_STATUS_NO_MEMORY;
545 }
546 } else {
547 nsarray = NULL;
548 }
549
550 /* now skip the header */
551
552 p += NS_HFIXEDSZ;
553
554 /* parse the query section */
555
556 for ( rrnum=0; rrnum<query_count; rrnum++ ) {
557 struct dns_query q;
558
559 if ( !ads_dns_parse_query( ctx, buffer, buffer+resp_len, &p, &q ) ) {
560 DEBUG(1,("ads_dns_lookup_ns: Failed to parse query record!\n"));
561 return NT_STATUS_UNSUCCESSFUL;
562 }
563 }
564
565 /* now we are at the answer section */
566
567 for ( rrnum=0; rrnum<answer_count; rrnum++ ) {
568 if ( !ads_dns_parse_rr_ns( ctx, buffer, buffer+resp_len, &p, &nsarray[rrnum] ) ) {
569 DEBUG(1,("ads_dns_lookup_ns: Failed to parse answer record!\n"));
570 return NT_STATUS_UNSUCCESSFUL;
571 }
572 }
573 idx = rrnum;
574
575 /* Parse the authority section */
576 /* just skip these for now */
577
578 for ( rrnum=0; rrnum<auth_count; rrnum++ ) {
579 struct dns_rr rr;
580
581 if ( !ads_dns_parse_rr( ctx, buffer, buffer+resp_len, &p, &rr ) ) {
582 DEBUG(1,("ads_dns_lookup_ns: Failed to parse authority record!\n"));
583 return NT_STATUS_UNSUCCESSFUL;
584 }
585 }
586
587 /* Parse the additional records section */
588
589 for ( rrnum=0; rrnum<additional_count; rrnum++ ) {
590 struct dns_rr rr;
591 int i;
592
593 if ( !ads_dns_parse_rr( ctx, buffer, buffer+resp_len, &p, &rr ) ) {
594 DEBUG(1,("ads_dns_lookup_ns: Failed to parse additional records section!\n"));
595 return NT_STATUS_UNSUCCESSFUL;
596 }
597
598 /* only interested in A records as a shortcut for having to come
599 back later and lookup the name */
600
601 if ( (rr.type != T_A) || (rr.rdatalen != 4) )
602 continue;
603
604 for ( i=0; i<idx; i++ ) {
605 if ( strcmp( rr.hostname, nsarray[i].hostname ) == 0 ) {
606 uint8 *buf = (uint8*)&nsarray[i].ip.s_addr;
607 memcpy( buf, rr.rdata, 4 );
608 }
609 }
610 }
611
612 *nslist = nsarray;
613 *numns = idx;
614
615 return NT_STATUS_OK;
616}
617
618/****************************************************************************
619 Store and fetch the AD client sitename.
620****************************************************************************/
621
622#define SITENAME_KEY "AD_SITENAME/DOMAIN/%s"
623
624static char *sitename_key(const char *realm)
625{
626 char *keystr;
627
628 if (asprintf(&keystr, SITENAME_KEY, strupper_static(realm)) == -1) {
629 return NULL;
630 }
631
632 return keystr;
633}
634
635
636/****************************************************************************
637 Store the AD client sitename.
638 We store indefinately as every new CLDAP query will re-write this.
639****************************************************************************/
640
641BOOL sitename_store(const char *realm, const char *sitename)
642{
643 time_t expire;
644 BOOL ret = False;
645 char *key;
646
647 if (!gencache_init()) {
648 return False;
649 }
650
651 if (!realm || (strlen(realm) == 0)) {
652 DEBUG(0,("sitename_store: no realm\n"));
653 return False;
654 }
655
656 key = sitename_key(realm);
657
658 if (!sitename || (sitename && !*sitename)) {
659 DEBUG(5,("sitename_store: deleting empty sitename!\n"));
660 ret = gencache_del(key);
661 SAFE_FREE(key);
662 return ret;
663 }
664
665 expire = get_time_t_max(); /* Store indefinately. */
666
667 DEBUG(10,("sitename_store: realm = [%s], sitename = [%s], expire = [%u]\n",
668 realm, sitename, (unsigned int)expire ));
669
670 ret = gencache_set( key, sitename, expire );
671 SAFE_FREE(key);
672 return ret;
673}
674
675/****************************************************************************
676 Fetch the AD client sitename.
677 Caller must free.
678****************************************************************************/
679
680char *sitename_fetch(const char *realm)
681{
682 char *sitename = NULL;
683 time_t timeout;
684 BOOL ret = False;
685 const char *query_realm;
686 char *key;
687
688 if (!gencache_init()) {
689 return False;
690 }
691
692 if (!realm || (strlen(realm) == 0)) {
693 query_realm = lp_realm();
694 } else {
695 query_realm = realm;
696 }
697
698 key = sitename_key(query_realm);
699
700 ret = gencache_get( key, &sitename, &timeout );
701 SAFE_FREE(key);
702 if ( !ret ) {
703 DEBUG(5,("sitename_fetch: No stored sitename for %s\n",
704 query_realm));
705 } else {
706 DEBUG(5,("sitename_fetch: Returning sitename for %s: \"%s\"\n",
707 query_realm, sitename ));
708 }
709 return sitename;
710}
711
712/****************************************************************************
713 Did the sitename change ?
714****************************************************************************/
715
716BOOL stored_sitename_changed(const char *realm, const char *sitename)
717{
718 BOOL ret = False;
719
720 char *new_sitename;
721
722 if (!realm || (strlen(realm) == 0)) {
723 DEBUG(0,("stored_sitename_changed: no realm\n"));
724 return False;
725 }
726
727 new_sitename = sitename_fetch(realm);
728
729 if (sitename && new_sitename && !strequal(sitename, new_sitename)) {
730 ret = True;
731 } else if ((sitename && !new_sitename) ||
732 (!sitename && new_sitename)) {
733 ret = True;
734 }
735 SAFE_FREE(new_sitename);
736 return ret;
737}
738
739/********************************************************************
740 Query with optional sitename.
741********************************************************************/
742
743static NTSTATUS ads_dns_query_internal(TALLOC_CTX *ctx,
744 const char *servicename,
745 const char *dc_pdc_gc_domains,
746 const char *realm,
747 const char *sitename,
748 struct dns_rr_srv **dclist,
749 int *numdcs )
750{
751 char *name;
752 if (sitename) {
753 name = talloc_asprintf(ctx, "%s._tcp.%s._sites.%s._msdcs.%s",
754 servicename, sitename,
755 dc_pdc_gc_domains, realm);
756 } else {
757 name = talloc_asprintf(ctx, "%s._tcp.%s._msdcs.%s",
758 servicename, dc_pdc_gc_domains, realm);
759 }
760 if (!name) {
761 return NT_STATUS_NO_MEMORY;
762 }
763 return ads_dns_lookup_srv( ctx, name, dclist, numdcs );
764}
765
766/********************************************************************
767 Query for AD DC's.
768********************************************************************/
769
770NTSTATUS ads_dns_query_dcs(TALLOC_CTX *ctx,
771 const char *realm,
772 const char *sitename,
773 struct dns_rr_srv **dclist,
774 int *numdcs )
775{
776 NTSTATUS status;
777
778 status = ads_dns_query_internal(ctx, "_ldap", "dc", realm, sitename,
779 dclist, numdcs);
780
781 if (NT_STATUS_EQUAL(status, NT_STATUS_IO_TIMEOUT) ||
782 NT_STATUS_EQUAL(status, NT_STATUS_CONNECTION_REFUSED)) {
783 return status;
784 }
785
786 if (sitename &&
787 ((!NT_STATUS_IS_OK(status)) ||
788 (NT_STATUS_IS_OK(status) && (numdcs == 0)))) {
789 /* Sitename DNS query may have failed. Try without. */
790 status = ads_dns_query_internal(ctx, "_ldap", "dc", realm,
791 NULL, dclist, numdcs);
792 }
793 return status;
794}
795
796/********************************************************************
797 Query for AD GC's.
798********************************************************************/
799
800NTSTATUS ads_dns_query_gcs(TALLOC_CTX *ctx,
801 const char *realm,
802 const char *sitename,
803 struct dns_rr_srv **dclist,
804 int *numdcs )
805{
806 NTSTATUS status;
807
808 status = ads_dns_query_internal(ctx, "_ldap", "gc", realm, sitename,
809 dclist, numdcs);
810
811 if (NT_STATUS_EQUAL(status, NT_STATUS_IO_TIMEOUT) ||
812 NT_STATUS_EQUAL(status, NT_STATUS_CONNECTION_REFUSED)) {
813 return status;
814 }
815
816 if (sitename &&
817 ((!NT_STATUS_IS_OK(status)) ||
818 (NT_STATUS_IS_OK(status) && (numdcs == 0)))) {
819 /* Sitename DNS query may have failed. Try without. */
820 status = ads_dns_query_internal(ctx, "_ldap", "gc", realm,
821 NULL, dclist, numdcs);
822 }
823 return status;
824}
825
826/********************************************************************
827 Query for AD KDC's.
828 Even if our underlying kerberos libraries are UDP only, this
829 is pretty safe as it's unlikely that a KDC supports TCP and not UDP.
830********************************************************************/
831
832NTSTATUS ads_dns_query_kdcs(TALLOC_CTX *ctx,
833 const char *dns_forest_name,
834 const char *sitename,
835 struct dns_rr_srv **dclist,
836 int *numdcs )
837{
838 NTSTATUS status;
839
840 status = ads_dns_query_internal(ctx, "_kerberos", "dc",
841 dns_forest_name, sitename, dclist,
842 numdcs);
843
844 if (NT_STATUS_EQUAL(status, NT_STATUS_IO_TIMEOUT) ||
845 NT_STATUS_EQUAL(status, NT_STATUS_CONNECTION_REFUSED)) {
846 return status;
847 }
848
849 if (sitename &&
850 ((!NT_STATUS_IS_OK(status)) ||
851 (NT_STATUS_IS_OK(status) && (numdcs == 0)))) {
852 /* Sitename DNS query may have failed. Try without. */
853 status = ads_dns_query_internal(ctx, "_kerberos", "dc",
854 dns_forest_name, NULL,
855 dclist, numdcs);
856 }
857 return status;
858}
859
860/********************************************************************
861 Query for AD PDC. Sitename is obsolete here.
862********************************************************************/
863
864NTSTATUS ads_dns_query_pdc(TALLOC_CTX *ctx,
865 const char *dns_domain_name,
866 struct dns_rr_srv **dclist,
867 int *numdcs )
868{
869 return ads_dns_query_internal(ctx, "_ldap", "pdc", dns_domain_name,
870 NULL, dclist, numdcs);
871}
872
873/********************************************************************
874 Query for AD DC by guid. Sitename is obsolete here.
875********************************************************************/
876
877NTSTATUS ads_dns_query_dcs_guid(TALLOC_CTX *ctx,
878 const char *dns_forest_name,
879 const struct GUID *domain_guid,
880 struct dns_rr_srv **dclist,
881 int *numdcs )
882{
883 /*_ldap._tcp.DomainGuid.domains._msdcs.DnsForestName */
884
885 const char *domains;
886 const char *guid_string;
887
888 guid_string = GUID_string(ctx, domain_guid);
889 if (!guid_string) {
890 return NT_STATUS_NO_MEMORY;
891 }
892
893 /* little hack */
894 domains = talloc_asprintf(ctx, "%s.domains", guid_string);
895 if (!domains) {
896 return NT_STATUS_NO_MEMORY;
897 }
898
899 return ads_dns_query_internal(ctx, "_ldap", domains, dns_forest_name,
900 NULL, dclist, numdcs);
901}
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