source: trunk/server/source3/libads/dns.c@ 1012

Last change on this file since 1012 was 745, checked in by Silvan Scherrer, 13 years ago

Samba Server: updated trunk to 3.6.0
File size: 23.2 KB
Line 
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#include "../librpc/ndr/libndr.h"
24
25/* AIX resolv.h uses 'class' in struct ns_rr */
26
27#if defined(AIX)
28# if defined(class)
29# undef class
30# endif
31#endif /* AIX */
32
33/* resolver headers */
34
35#include <sys/types.h>
36#include <netinet/in.h>
37#include <arpa/nameser.h>
38#include <resolv.h>
39#include <netdb.h>
40
41#define MAX_DNS_PACKET_SIZE 0xffff
42
43#ifdef NS_HFIXEDSZ /* Bind 8/9 interface */
44#if !defined(C_IN) /* AIX 5.3 already defines C_IN */
45# define C_IN ns_c_in
46#endif
47#if !defined(T_A) /* AIX 5.3 already defines T_A */
48# define T_A ns_t_a
49#endif
50
51#if defined(HAVE_IPV6)
52#if !defined(T_AAAA)
53# define T_AAAA ns_t_aaaa
54#endif
55#endif
56
57# define T_SRV ns_t_srv
58#if !defined(T_NS) /* AIX 5.3 already defines T_NS */
59# define T_NS ns_t_ns
60#endif
61#else
62# ifdef HFIXEDSZ
63# define NS_HFIXEDSZ HFIXEDSZ
64# else
65# define NS_HFIXEDSZ sizeof(HEADER)
66# endif /* HFIXEDSZ */
67# ifdef PACKETSZ
68# define NS_PACKETSZ PACKETSZ
69# else /* 512 is usually the default */
70# define NS_PACKETSZ 512
71# endif /* PACKETSZ */
72# define T_SRV 33
73#endif
74
75/*********************************************************************
76*********************************************************************/
77
78static bool ads_dns_parse_query( TALLOC_CTX *ctx, uint8 *start, uint8 *end,
79 uint8 **ptr, struct dns_query *q )
80{
81 uint8 *p = *ptr;
82 char hostname[MAX_DNS_NAME_LENGTH];
83 int namelen;
84
85 ZERO_STRUCTP( q );
86
87 if ( !start || !end || !q || !*ptr)
88 return False;
89
90 /* See RFC 1035 for details. If this fails, then return. */
91
92 namelen = dn_expand( start, end, p, hostname, sizeof(hostname) );
93 if ( namelen < 0 ) {
94 return False;
95 }
96 p += namelen;
97 q->hostname = talloc_strdup( ctx, hostname );
98
99 /* check that we have space remaining */
100
101 if ( PTR_DIFF(p+4, end) > 0 )
102 return False;
103
104 q->type = RSVAL( p, 0 );
105 q->in_class = RSVAL( p, 2 );
106 p += 4;
107
108 *ptr = p;
109
110 return True;
111}
112
113/*********************************************************************
114*********************************************************************/
115
116static bool ads_dns_parse_rr( TALLOC_CTX *ctx, uint8 *start, uint8 *end,
117 uint8 **ptr, struct dns_rr *rr )
118{
119 uint8 *p = *ptr;
120 char hostname[MAX_DNS_NAME_LENGTH];
121 int namelen;
122
123 if ( !start || !end || !rr || !*ptr)
124 return -1;
125
126 ZERO_STRUCTP( rr );
127 /* pull the name from the answer */
128
129 namelen = dn_expand( start, end, p, hostname, sizeof(hostname) );
130 if ( namelen < 0 ) {
131 return -1;
132 }
133 p += namelen;
134 rr->hostname = talloc_strdup( ctx, hostname );
135
136 /* check that we have space remaining */
137
138 if ( PTR_DIFF(p+10, end) > 0 )
139 return False;
140
141 /* pull some values and then skip onto the string */
142
143 rr->type = RSVAL(p, 0);
144 rr->in_class = RSVAL(p, 2);
145 rr->ttl = RIVAL(p, 4);
146 rr->rdatalen = RSVAL(p, 8);
147
148 p += 10;
149
150 /* sanity check the available space */
151
152 if ( PTR_DIFF(p+rr->rdatalen, end ) > 0 ) {
153 return False;
154
155 }
156
157 /* save a point to the rdata for this section */
158
159 rr->rdata = p;
160 p += rr->rdatalen;
161
162 *ptr = p;
163
164 return True;
165}
166
167/*********************************************************************
168*********************************************************************/
169
170static bool ads_dns_parse_rr_srv( TALLOC_CTX *ctx, uint8 *start, uint8 *end,
171 uint8 **ptr, struct dns_rr_srv *srv )
172{
173 struct dns_rr rr;
174 uint8 *p;
175 char dcname[MAX_DNS_NAME_LENGTH];
176 int namelen;
177
178 if ( !start || !end || !srv || !*ptr)
179 return -1;
180
181 /* Parse the RR entry. Coming out of the this, ptr is at the beginning
182 of the next record */
183
184 if ( !ads_dns_parse_rr( ctx, start, end, ptr, &rr ) ) {
185 DEBUG(1,("ads_dns_parse_rr_srv: Failed to parse RR record\n"));
186 return False;
187 }
188
189 if ( rr.type != T_SRV ) {
190 DEBUG(1,("ads_dns_parse_rr_srv: Bad answer type (%d)\n",
191 rr.type));
192 return False;
193 }
194
195 p = rr.rdata;
196
197 srv->priority = RSVAL(p, 0);
198 srv->weight = RSVAL(p, 2);
199 srv->port = RSVAL(p, 4);
200
201 p += 6;
202
203 namelen = dn_expand( start, end, p, dcname, sizeof(dcname) );
204 if ( namelen < 0 ) {
205 DEBUG(1,("ads_dns_parse_rr_srv: Failed to uncompress name!\n"));
206 return False;
207 }
208
209 srv->hostname = talloc_strdup( ctx, dcname );
210
211 DEBUG(10,("ads_dns_parse_rr_srv: Parsed %s [%u, %u, %u]\n",
212 srv->hostname,
213 srv->priority,
214 srv->weight,
215 srv->port));
216
217 return True;
218}
219
220/*********************************************************************
221*********************************************************************/
222
223static bool ads_dns_parse_rr_ns( TALLOC_CTX *ctx, uint8 *start, uint8 *end,
224 uint8 **ptr, struct dns_rr_ns *nsrec )
225{
226 struct dns_rr rr;
227 uint8 *p;
228 char nsname[MAX_DNS_NAME_LENGTH];
229 int namelen;
230
231 if ( !start || !end || !nsrec || !*ptr)
232 return -1;
233
234 /* Parse the RR entry. Coming out of the this, ptr is at the beginning
235 of the next record */
236
237 if ( !ads_dns_parse_rr( ctx, start, end, ptr, &rr ) ) {
238 DEBUG(1,("ads_dns_parse_rr_ns: Failed to parse RR record\n"));
239 return False;
240 }
241
242 if ( rr.type != T_NS ) {
243 DEBUG(1,("ads_dns_parse_rr_ns: Bad answer type (%d)\n",
244 rr.type));
245 return False;
246 }
247
248 p = rr.rdata;
249
250 /* ame server hostname */
251
252 namelen = dn_expand( start, end, p, nsname, sizeof(nsname) );
253 if ( namelen < 0 ) {
254 DEBUG(1,("ads_dns_parse_rr_ns: Failed to uncompress name!\n"));
255 return False;
256 }
257 nsrec->hostname = talloc_strdup( ctx, nsname );
258
259 return True;
260}
261
262/*********************************************************************
263 Sort SRV record list based on weight and priority. See RFC 2782.
264*********************************************************************/
265
266static int dnssrvcmp( struct dns_rr_srv *a, struct dns_rr_srv *b )
267{
268 if ( a->priority == b->priority ) {
269
270 /* randomize entries with an equal weight and priority */
271 if ( a->weight == b->weight )
272 return 0;
273
274 /* higher weights should be sorted lower */
275 if ( a->weight > b->weight )
276 return -1;
277 else
278 return 1;
279 }
280
281 if ( a->priority < b->priority )
282 return -1;
283
284 return 1;
285}
286
287/*********************************************************************
288 Simple wrapper for a DNS query
289*********************************************************************/
290
291#define DNS_FAILED_WAITTIME 30
292
293static NTSTATUS dns_send_req( TALLOC_CTX *ctx, const char *name, int q_type,
294 uint8 **buf, int *resp_length )
295{
296 uint8 *buffer = NULL;
297 size_t buf_len = 0;
298 int resp_len = NS_PACKETSZ;
299 static time_t last_dns_check = 0;
300 static NTSTATUS last_dns_status = NT_STATUS_OK;
301 time_t now = time_mono(NULL);
302
303 /* Try to prevent bursts of DNS lookups if the server is down */
304
305 /* Protect against large clock changes */
306
307 if ( last_dns_check > now )
308 last_dns_check = 0;
309
310 /* IF we had a DNS timeout or a bad server and we are still
311 in the 30 second cache window, just return the previous
312 status and save the network timeout. */
313
314 if ( (NT_STATUS_EQUAL(last_dns_status,NT_STATUS_IO_TIMEOUT) ||
315 NT_STATUS_EQUAL(last_dns_status,NT_STATUS_CONNECTION_REFUSED)) &&
316 (last_dns_check+DNS_FAILED_WAITTIME) > now )
317 {
318 DEBUG(10,("last_dns_check: Returning cached status (%s)\n",
319 nt_errstr(last_dns_status) ));
320 return last_dns_status;
321 }
322
323 /* Send the Query */
324 do {
325 if ( buffer )
326 TALLOC_FREE( buffer );
327
328 buf_len = resp_len * sizeof(uint8);
329
330 if (buf_len) {
331 if ((buffer = TALLOC_ARRAY(ctx, uint8, buf_len))
332 == NULL ) {
333 DEBUG(0,("ads_dns_lookup_srv: "
334 "talloc() failed!\n"));
335 last_dns_status = NT_STATUS_NO_MEMORY;
336 last_dns_check = time_mono(NULL);
337 return last_dns_status;
338 }
339 }
340
341 if ((resp_len = res_query(name, C_IN, q_type, buffer, buf_len))
342 < 0 ) {
343 DEBUG(3,("ads_dns_lookup_srv: "
344 "Failed to resolve %s (%s)\n",
345 name, strerror(errno)));
346 TALLOC_FREE( buffer );
347 last_dns_status = NT_STATUS_UNSUCCESSFUL;
348
349 if (errno == ETIMEDOUT) {
350 last_dns_status = NT_STATUS_IO_TIMEOUT;
351 }
352 if (errno == ECONNREFUSED) {
353 last_dns_status = NT_STATUS_CONNECTION_REFUSED;
354 }
355 last_dns_check = time_mono(NULL);
356 return last_dns_status;
357 }
358
359 /* On AIX, Solaris, and possibly some older glibc systems (e.g. SLES8)
360 truncated replies never give back a resp_len > buflen
361 which ends up causing DNS resolve failures on large tcp DNS replies */
362
363 if (buf_len == resp_len) {
364 if (resp_len == MAX_DNS_PACKET_SIZE) {
365 DEBUG(1,("dns_send_req: DNS reply too large when resolving %s\n",
366 name));
367 TALLOC_FREE( buffer );
368 last_dns_status = NT_STATUS_BUFFER_TOO_SMALL;
369 last_dns_check = time_mono(NULL);
370 return last_dns_status;
371 }
372
373 resp_len = MIN(resp_len*2, MAX_DNS_PACKET_SIZE);
374 }
375
376
377 } while ( buf_len < resp_len && resp_len <= MAX_DNS_PACKET_SIZE );
378
379 *buf = buffer;
380 *resp_length = resp_len;
381
382 last_dns_check = time_mono(NULL);
383 last_dns_status = NT_STATUS_OK;
384 return last_dns_status;
385}
386
387/*********************************************************************
388 Simple wrapper for a DNS SRV query
389*********************************************************************/
390
391static NTSTATUS ads_dns_lookup_srv( TALLOC_CTX *ctx,
392 const char *name,
393 struct dns_rr_srv **dclist,
394 int *numdcs)
395{
396 uint8 *buffer = NULL;
397 int resp_len = 0;
398 struct dns_rr_srv *dcs = NULL;
399 int query_count, answer_count, auth_count, additional_count;
400 uint8 *p = buffer;
401 int rrnum;
402 int idx = 0;
403 NTSTATUS status;
404
405 if ( !ctx || !name || !dclist ) {
406 return NT_STATUS_INVALID_PARAMETER;
407 }
408
409 /* Send the request. May have to loop several times in case
410 of large replies */
411
412 status = dns_send_req( ctx, name, T_SRV, &buffer, &resp_len );
413 if ( !NT_STATUS_IS_OK(status) ) {
414 DEBUG(3,("ads_dns_lookup_srv: Failed to send DNS query (%s)\n",
415 nt_errstr(status)));
416 return status;
417 }
418 p = buffer;
419
420 /* For some insane reason, the ns_initparse() et. al. routines are only
421 available in libresolv.a, and not the shared lib. Who knows why....
422 So we have to parse the DNS reply ourselves */
423
424 /* Pull the answer RR's count from the header.
425 * Use the NMB ordering macros */
426
427 query_count = RSVAL( p, 4 );
428 answer_count = RSVAL( p, 6 );
429 auth_count = RSVAL( p, 8 );
430 additional_count = RSVAL( p, 10 );
431
432 DEBUG(4,("ads_dns_lookup_srv: "
433 "%d records returned in the answer section.\n",
434 answer_count));
435
436 if (answer_count) {
437 if ((dcs = TALLOC_ZERO_ARRAY(ctx, struct dns_rr_srv,
438 answer_count)) == NULL ) {
439 DEBUG(0,("ads_dns_lookup_srv: "
440 "talloc() failure for %d char*'s\n",
441 answer_count));
442 return NT_STATUS_NO_MEMORY;
443 }
444 } else {
445 dcs = NULL;
446 }
447
448 /* now skip the header */
449
450 p += NS_HFIXEDSZ;
451
452 /* parse the query section */
453
454 for ( rrnum=0; rrnum<query_count; rrnum++ ) {
455 struct dns_query q;
456
457 if (!ads_dns_parse_query(ctx, buffer,
458 buffer+resp_len, &p, &q)) {
459 DEBUG(1,("ads_dns_lookup_srv: "
460 "Failed to parse query record [%d]!\n", rrnum));
461 return NT_STATUS_UNSUCCESSFUL;
462 }
463 }
464
465 /* now we are at the answer section */
466
467 for ( rrnum=0; rrnum<answer_count; rrnum++ ) {
468 if (!ads_dns_parse_rr_srv(ctx, buffer, buffer+resp_len,
469 &p, &dcs[rrnum])) {
470 DEBUG(1,("ads_dns_lookup_srv: "
471 "Failed to parse answer recordi [%d]!\n", rrnum));
472 return NT_STATUS_UNSUCCESSFUL;
473 }
474 }
475 idx = rrnum;
476
477 /* Parse the authority section */
478 /* just skip these for now */
479
480 for ( rrnum=0; rrnum<auth_count; rrnum++ ) {
481 struct dns_rr rr;
482
483 if (!ads_dns_parse_rr( ctx, buffer,
484 buffer+resp_len, &p, &rr)) {
485 DEBUG(1,("ads_dns_lookup_srv: "
486 "Failed to parse authority record! [%d]\n", rrnum));
487 return NT_STATUS_UNSUCCESSFUL;
488 }
489 }
490
491 /* Parse the additional records section */
492
493 for ( rrnum=0; rrnum<additional_count; rrnum++ ) {
494 struct dns_rr rr;
495 int i;
496
497 if (!ads_dns_parse_rr(ctx, buffer, buffer+resp_len,
498 &p, &rr)) {
499 DEBUG(1,("ads_dns_lookup_srv: Failed "
500 "to parse additional records section! [%d]\n", rrnum));
501 return NT_STATUS_UNSUCCESSFUL;
502 }
503
504 /* Only interested in A or AAAA records as a shortcut for having
505 * to come back later and lookup the name. For multi-homed
506 * hosts, the number of additional records and exceed the
507 * number of answer records. */
508
509 if (rr.type != T_A || rr.rdatalen != 4) {
510#if defined(HAVE_IPV6)
511 /* RFC2874 defines A6 records. This
512 * requires recusive and horribly complex lookups.
513 * Bastards. Ignore this for now.... JRA.
514 * Luckily RFC3363 reprecates A6 records.
515 */
516 if (rr.type != T_AAAA || rr.rdatalen != 16)
517#endif
518 continue;
519 }
520
521 for ( i=0; i<idx; i++ ) {
522 if ( strcmp( rr.hostname, dcs[i].hostname ) == 0 ) {
523 int num_ips = dcs[i].num_ips;
524 struct sockaddr_storage *tmp_ss_s;
525
526 /* allocate new memory */
527
528 if (dcs[i].num_ips == 0) {
529 if ((dcs[i].ss_s = TALLOC_ARRAY(dcs,
530 struct sockaddr_storage, 1 ))
531 == NULL ) {
532 return NT_STATUS_NO_MEMORY;
533 }
534 } else {
535 if ((tmp_ss_s = TALLOC_REALLOC_ARRAY(dcs,
536 dcs[i].ss_s,
537 struct sockaddr_storage,
538 dcs[i].num_ips+1))
539 == NULL ) {
540 return NT_STATUS_NO_MEMORY;
541 }
542
543 dcs[i].ss_s = tmp_ss_s;
544 }
545 dcs[i].num_ips++;
546
547 /* copy the new IP address */
548 if (rr.type == T_A) {
549 struct in_addr ip;
550 memcpy(&ip, rr.rdata, 4);
551 in_addr_to_sockaddr_storage(
552 &dcs[i].ss_s[num_ips],
553 ip);
554 }
555#if defined(HAVE_IPV6)
556 if (rr.type == T_AAAA) {
557 struct in6_addr ip6;
558 memcpy(&ip6, rr.rdata, rr.rdatalen);
559 in6_addr_to_sockaddr_storage(
560 &dcs[i].ss_s[num_ips],
561 ip6);
562 }
563#endif
564 }
565 }
566 }
567
568 TYPESAFE_QSORT(dcs, idx, dnssrvcmp );
569
570 *dclist = dcs;
571 *numdcs = idx;
572
573 return NT_STATUS_OK;
574}
575
576/*********************************************************************
577 Simple wrapper for a DNS NS query
578*********************************************************************/
579
580NTSTATUS ads_dns_lookup_ns(TALLOC_CTX *ctx,
581 const char *dnsdomain,
582 struct dns_rr_ns **nslist,
583 int *numns)
584{
585 uint8 *buffer = NULL;
586 int resp_len = 0;
587 struct dns_rr_ns *nsarray = NULL;
588 int query_count, answer_count, auth_count, additional_count;
589 uint8 *p;
590 int rrnum;
591 int idx = 0;
592 NTSTATUS status;
593
594 if ( !ctx || !dnsdomain || !nslist ) {
595 return NT_STATUS_INVALID_PARAMETER;
596 }
597
598 /* Send the request. May have to loop several times in case
599 of large replies */
600
601 status = dns_send_req( ctx, dnsdomain, T_NS, &buffer, &resp_len );
602 if ( !NT_STATUS_IS_OK(status) ) {
603 DEBUG(3,("ads_dns_lookup_ns: Failed to send DNS query (%s)\n",
604 nt_errstr(status)));
605 return status;
606 }
607 p = buffer;
608
609 /* For some insane reason, the ns_initparse() et. al. routines are only
610 available in libresolv.a, and not the shared lib. Who knows why....
611 So we have to parse the DNS reply ourselves */
612
613 /* Pull the answer RR's count from the header.
614 * Use the NMB ordering macros */
615
616 query_count = RSVAL( p, 4 );
617 answer_count = RSVAL( p, 6 );
618 auth_count = RSVAL( p, 8 );
619 additional_count = RSVAL( p, 10 );
620
621 DEBUG(4,("ads_dns_lookup_ns: "
622 "%d records returned in the answer section.\n",
623 answer_count));
624
625 if (answer_count) {
626 if ((nsarray = TALLOC_ARRAY(ctx, struct dns_rr_ns,
627 answer_count)) == NULL ) {
628 DEBUG(0,("ads_dns_lookup_ns: "
629 "talloc() failure for %d char*'s\n",
630 answer_count));
631 return NT_STATUS_NO_MEMORY;
632 }
633 } else {
634 nsarray = NULL;
635 }
636
637 /* now skip the header */
638
639 p += NS_HFIXEDSZ;
640
641 /* parse the query section */
642
643 for ( rrnum=0; rrnum<query_count; rrnum++ ) {
644 struct dns_query q;
645
646 if (!ads_dns_parse_query(ctx, buffer, buffer+resp_len,
647 &p, &q)) {
648 DEBUG(1,("ads_dns_lookup_ns: "
649 " Failed to parse query record!\n"));
650 return NT_STATUS_UNSUCCESSFUL;
651 }
652 }
653
654 /* now we are at the answer section */
655
656 for ( rrnum=0; rrnum<answer_count; rrnum++ ) {
657 if (!ads_dns_parse_rr_ns(ctx, buffer, buffer+resp_len,
658 &p, &nsarray[rrnum])) {
659 DEBUG(1,("ads_dns_lookup_ns: "
660 "Failed to parse answer record!\n"));
661 return NT_STATUS_UNSUCCESSFUL;
662 }
663 }
664 idx = rrnum;
665
666 /* Parse the authority section */
667 /* just skip these for now */
668
669 for ( rrnum=0; rrnum<auth_count; rrnum++ ) {
670 struct dns_rr rr;
671
672 if ( !ads_dns_parse_rr(ctx, buffer, buffer+resp_len,
673 &p, &rr)) {
674 DEBUG(1,("ads_dns_lookup_ns: "
675 "Failed to parse authority record!\n"));
676 return NT_STATUS_UNSUCCESSFUL;
677 }
678 }
679
680 /* Parse the additional records section */
681
682 for ( rrnum=0; rrnum<additional_count; rrnum++ ) {
683 struct dns_rr rr;
684 int i;
685
686 if (!ads_dns_parse_rr(ctx, buffer, buffer+resp_len,
687 &p, &rr)) {
688 DEBUG(1,("ads_dns_lookup_ns: Failed "
689 "to parse additional records section!\n"));
690 return NT_STATUS_UNSUCCESSFUL;
691 }
692
693 /* only interested in A records as a shortcut for having to come
694 back later and lookup the name */
695
696 if (rr.type != T_A || rr.rdatalen != 4) {
697#if defined(HAVE_IPV6)
698 if (rr.type != T_AAAA || rr.rdatalen != 16)
699#endif
700 continue;
701 }
702
703 for ( i=0; i<idx; i++ ) {
704 if (strcmp(rr.hostname, nsarray[i].hostname) == 0) {
705 if (rr.type == T_A) {
706 struct in_addr ip;
707 memcpy(&ip, rr.rdata, 4);
708 in_addr_to_sockaddr_storage(
709 &nsarray[i].ss,
710 ip);
711 }
712#if defined(HAVE_IPV6)
713 if (rr.type == T_AAAA) {
714 struct in6_addr ip6;
715 memcpy(&ip6, rr.rdata, rr.rdatalen);
716 in6_addr_to_sockaddr_storage(
717 &nsarray[i].ss,
718 ip6);
719 }
720#endif
721 }
722 }
723 }
724
725 *nslist = nsarray;
726 *numns = idx;
727
728 return NT_STATUS_OK;
729}
730
731/********************************************************************
732 Query with optional sitename.
733********************************************************************/
734
735static NTSTATUS ads_dns_query_internal(TALLOC_CTX *ctx,
736 const char *servicename,
737 const char *dc_pdc_gc_domains,
738 const char *realm,
739 const char *sitename,
740 struct dns_rr_srv **dclist,
741 int *numdcs )
742{
743 char *name;
744 if (sitename) {
745 name = talloc_asprintf(ctx, "%s._tcp.%s._sites.%s._msdcs.%s",
746 servicename, sitename,
747 dc_pdc_gc_domains, realm);
748 } else {
749 name = talloc_asprintf(ctx, "%s._tcp.%s._msdcs.%s",
750 servicename, dc_pdc_gc_domains, realm);
751 }
752 if (!name) {
753 return NT_STATUS_NO_MEMORY;
754 }
755 return ads_dns_lookup_srv( ctx, name, dclist, numdcs );
756}
757
758/********************************************************************
759 Query for AD DC's.
760********************************************************************/
761
762NTSTATUS ads_dns_query_dcs(TALLOC_CTX *ctx,
763 const char *realm,
764 const char *sitename,
765 struct dns_rr_srv **dclist,
766 int *numdcs )
767{
768 NTSTATUS status;
769
770 status = ads_dns_query_internal(ctx, "_ldap", "dc", realm, sitename,
771 dclist, numdcs);
772
773 if (NT_STATUS_EQUAL(status, NT_STATUS_IO_TIMEOUT) ||
774 NT_STATUS_EQUAL(status, NT_STATUS_CONNECTION_REFUSED)) {
775 return status;
776 }
777
778 if (sitename &&
779 ((!NT_STATUS_IS_OK(status)) ||
780 (NT_STATUS_IS_OK(status) && (numdcs == 0)))) {
781 /* Sitename DNS query may have failed. Try without. */
782 status = ads_dns_query_internal(ctx, "_ldap", "dc", realm,
783 NULL, dclist, numdcs);
784 }
785 return status;
786}
787
788/********************************************************************
789 Query for AD GC's.
790********************************************************************/
791
792NTSTATUS ads_dns_query_gcs(TALLOC_CTX *ctx,
793 const char *realm,
794 const char *sitename,
795 struct dns_rr_srv **dclist,
796 int *numdcs )
797{
798 NTSTATUS status;
799
800 status = ads_dns_query_internal(ctx, "_ldap", "gc", realm, sitename,
801 dclist, numdcs);
802
803 if (NT_STATUS_EQUAL(status, NT_STATUS_IO_TIMEOUT) ||
804 NT_STATUS_EQUAL(status, NT_STATUS_CONNECTION_REFUSED)) {
805 return status;
806 }
807
808 if (sitename &&
809 ((!NT_STATUS_IS_OK(status)) ||
810 (NT_STATUS_IS_OK(status) && (numdcs == 0)))) {
811 /* Sitename DNS query may have failed. Try without. */
812 status = ads_dns_query_internal(ctx, "_ldap", "gc", realm,
813 NULL, dclist, numdcs);
814 }
815 return status;
816}
817
818/********************************************************************
819 Query for AD KDC's.
820 Even if our underlying kerberos libraries are UDP only, this
821 is pretty safe as it's unlikely that a KDC supports TCP and not UDP.
822********************************************************************/
823
824NTSTATUS ads_dns_query_kdcs(TALLOC_CTX *ctx,
825 const char *dns_forest_name,
826 const char *sitename,
827 struct dns_rr_srv **dclist,
828 int *numdcs )
829{
830 NTSTATUS status;
831
832 status = ads_dns_query_internal(ctx, "_kerberos", "dc",
833 dns_forest_name, sitename, dclist,
834 numdcs);
835
836 if (NT_STATUS_EQUAL(status, NT_STATUS_IO_TIMEOUT) ||
837 NT_STATUS_EQUAL(status, NT_STATUS_CONNECTION_REFUSED)) {
838 return status;
839 }
840
841 if (sitename &&
842 ((!NT_STATUS_IS_OK(status)) ||
843 (NT_STATUS_IS_OK(status) && (numdcs == 0)))) {
844 /* Sitename DNS query may have failed. Try without. */
845 status = ads_dns_query_internal(ctx, "_kerberos", "dc",
846 dns_forest_name, NULL,
847 dclist, numdcs);
848 }
849 return status;
850}
851
852/********************************************************************
853 Query for AD PDC. Sitename is obsolete here.
854********************************************************************/
855
856NTSTATUS ads_dns_query_pdc(TALLOC_CTX *ctx,
857 const char *dns_domain_name,
858 struct dns_rr_srv **dclist,
859 int *numdcs )
860{
861 return ads_dns_query_internal(ctx, "_ldap", "pdc", dns_domain_name,
862 NULL, dclist, numdcs);
863}
864
865/********************************************************************
866 Query for AD DC by guid. Sitename is obsolete here.
867********************************************************************/
868
869NTSTATUS ads_dns_query_dcs_guid(TALLOC_CTX *ctx,
870 const char *dns_forest_name,
871 const struct GUID *domain_guid,
872 struct dns_rr_srv **dclist,
873 int *numdcs )
874{
875 /*_ldap._tcp.DomainGuid.domains._msdcs.DnsForestName */
876
877 const char *domains;
878 char *guid_string;
879
880 guid_string = GUID_string(ctx, domain_guid);
881 if (!guid_string) {
882 return NT_STATUS_NO_MEMORY;
883 }
884
885 /* little hack */
886 domains = talloc_asprintf(ctx, "%s.domains", guid_string);
887 if (!domains) {
888 return NT_STATUS_NO_MEMORY;
889 }
890 TALLOC_FREE(guid_string);
891
892 return ads_dns_query_internal(ctx, "_ldap", domains, dns_forest_name,
893 NULL, dclist, numdcs);
894}
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