source: vendor/current/lib/addns/dnsquery.c

Last change on this file was 988, checked in by Silvan Scherrer, 9 years ago

Samba Server: update vendor to version 4.4.3
File size: 22.5 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 "lib/util/util_net.h"
23#include "lib/util/tsort.h"
24#include "dnsquery.h"
25
26/* AIX resolv.h uses 'class' in struct ns_rr */
27
28#if defined(AIX)
29# if defined(class)
30# undef class
31# endif
32#endif /* AIX */
33
34/* resolver headers */
35
36#include <sys/types.h>
37#include <netinet/in.h>
38#include <arpa/nameser.h>
39#include <resolv.h>
40#include <netdb.h>
41
42#define MAX_DNS_PACKET_SIZE 0xffff
43
44#ifdef NS_HFIXEDSZ /* Bind 8/9 interface */
45#if !defined(C_IN) /* AIX 5.3 already defines C_IN */
46# define C_IN ns_c_in
47#endif
48#if !defined(T_A) /* AIX 5.3 already defines T_A */
49# define T_A ns_t_a
50#endif
51
52#if defined(HAVE_IPV6)
53#if !defined(T_AAAA)
54# define T_AAAA ns_t_aaaa
55#endif
56#endif
57
58# define T_SRV ns_t_srv
59#if !defined(T_NS) /* AIX 5.3 already defines T_NS */
60# define T_NS ns_t_ns
61#endif
62#else
63# ifdef HFIXEDSZ
64# define NS_HFIXEDSZ HFIXEDSZ
65# else
66# define NS_HFIXEDSZ sizeof(HEADER)
67# endif /* HFIXEDSZ */
68# ifdef PACKETSZ
69# define NS_PACKETSZ PACKETSZ
70# else /* 512 is usually the default */
71# define NS_PACKETSZ 512
72# endif /* PACKETSZ */
73# define T_SRV 33
74#endif
75
76/*********************************************************************
77*********************************************************************/
78
79static bool ads_dns_parse_query( TALLOC_CTX *ctx, uint8_t *start, uint8_t *end,
80 uint8_t **ptr, struct dns_query *q )
81{
82 uint8_t *p = *ptr;
83 char hostname[MAX_DNS_NAME_LENGTH];
84 int namelen;
85
86 ZERO_STRUCTP( q );
87
88 if ( !start || !end || !q || !*ptr)
89 return false;
90
91 /* See RFC 1035 for details. If this fails, then return. */
92
93 namelen = dn_expand( start, end, p, hostname, sizeof(hostname) );
94 if ( namelen < 0 ) {
95 return false;
96 }
97 p += namelen;
98 q->hostname = talloc_strdup( ctx, hostname );
99
100 /* check that we have space remaining */
101
102 if ( PTR_DIFF(p+4, end) > 0 )
103 return false;
104
105 q->type = RSVAL( p, 0 );
106 q->in_class = RSVAL( p, 2 );
107 p += 4;
108
109 *ptr = p;
110
111 return true;
112}
113
114/*********************************************************************
115*********************************************************************/
116
117static bool ads_dns_parse_rr( TALLOC_CTX *ctx, uint8_t *start, uint8_t *end,
118 uint8_t **ptr, struct dns_rr *rr )
119{
120 uint8_t *p = *ptr;
121 char hostname[MAX_DNS_NAME_LENGTH];
122 int namelen;
123
124 if ( !start || !end || !rr || !*ptr)
125 return -1;
126
127 ZERO_STRUCTP( rr );
128 /* pull the name from the answer */
129
130 namelen = dn_expand( start, end, p, hostname, sizeof(hostname) );
131 if ( namelen < 0 ) {
132 return -1;
133 }
134 p += namelen;
135 rr->hostname = talloc_strdup( ctx, hostname );
136
137 /* check that we have space remaining */
138
139 if ( PTR_DIFF(p+10, end) > 0 )
140 return false;
141
142 /* pull some values and then skip onto the string */
143
144 rr->type = RSVAL(p, 0);
145 rr->in_class = RSVAL(p, 2);
146 rr->ttl = RIVAL(p, 4);
147 rr->rdatalen = RSVAL(p, 8);
148
149 p += 10;
150
151 /* sanity check the available space */
152
153 if ( PTR_DIFF(p+rr->rdatalen, end ) > 0 ) {
154 return false;
155
156 }
157
158 /* save a point to the rdata for this section */
159
160 rr->rdata = p;
161 p += rr->rdatalen;
162
163 *ptr = p;
164
165 return true;
166}
167
168/*********************************************************************
169*********************************************************************/
170
171static bool ads_dns_parse_rr_srv( TALLOC_CTX *ctx, uint8_t *start, uint8_t *end,
172 uint8_t **ptr, struct dns_rr_srv *srv )
173{
174 struct dns_rr rr;
175 uint8_t *p;
176 char dcname[MAX_DNS_NAME_LENGTH];
177 int namelen;
178
179 if ( !start || !end || !srv || !*ptr)
180 return -1;
181
182 /* Parse the RR entry. Coming out of the this, ptr is at the beginning
183 of the next record */
184
185 if ( !ads_dns_parse_rr( ctx, start, end, ptr, &rr ) ) {
186 DEBUG(1,("ads_dns_parse_rr_srv: Failed to parse RR record\n"));
187 return false;
188 }
189
190 if ( rr.type != T_SRV ) {
191 DEBUG(1,("ads_dns_parse_rr_srv: Bad answer type (%d)\n",
192 rr.type));
193 return false;
194 }
195
196 p = rr.rdata;
197
198 srv->priority = RSVAL(p, 0);
199 srv->weight = RSVAL(p, 2);
200 srv->port = RSVAL(p, 4);
201
202 p += 6;
203
204 namelen = dn_expand( start, end, p, dcname, sizeof(dcname) );
205 if ( namelen < 0 ) {
206 DEBUG(1,("ads_dns_parse_rr_srv: Failed to uncompress name!\n"));
207 return false;
208 }
209
210 srv->hostname = talloc_strdup( ctx, dcname );
211
212 DEBUG(10,("ads_dns_parse_rr_srv: Parsed %s [%u, %u, %u]\n",
213 srv->hostname,
214 srv->priority,
215 srv->weight,
216 srv->port));
217
218 return true;
219}
220
221/*********************************************************************
222*********************************************************************/
223
224static bool ads_dns_parse_rr_ns( TALLOC_CTX *ctx, uint8_t *start, uint8_t *end,
225 uint8_t **ptr, struct dns_rr_ns *nsrec )
226{
227 struct dns_rr rr;
228 uint8_t *p;
229 char nsname[MAX_DNS_NAME_LENGTH];
230 int namelen;
231
232 if ( !start || !end || !nsrec || !*ptr)
233 return -1;
234
235 /* Parse the RR entry. Coming out of the this, ptr is at the beginning
236 of the next record */
237
238 if ( !ads_dns_parse_rr( ctx, start, end, ptr, &rr ) ) {
239 DEBUG(1,("ads_dns_parse_rr_ns: Failed to parse RR record\n"));
240 return false;
241 }
242
243 if ( rr.type != T_NS ) {
244 DEBUG(1,("ads_dns_parse_rr_ns: Bad answer type (%d)\n",
245 rr.type));
246 return false;
247 }
248
249 p = rr.rdata;
250
251 /* ame server hostname */
252
253 namelen = dn_expand( start, end, p, nsname, sizeof(nsname) );
254 if ( namelen < 0 ) {
255 DEBUG(1,("ads_dns_parse_rr_ns: Failed to uncompress name!\n"));
256 return false;
257 }
258 nsrec->hostname = talloc_strdup( ctx, nsname );
259
260 return true;
261}
262
263/*********************************************************************
264 Sort SRV record list based on weight and priority. See RFC 2782.
265*********************************************************************/
266
267static int dnssrvcmp( struct dns_rr_srv *a, struct dns_rr_srv *b )
268{
269 if ( a->priority == b->priority ) {
270
271 /* randomize entries with an equal weight and priority */
272 if ( a->weight == b->weight )
273 return 0;
274
275 /* higher weights should be sorted lower */
276 if ( a->weight > b->weight )
277 return -1;
278 else
279 return 1;
280 }
281
282 if ( a->priority < b->priority )
283 return -1;
284
285 return 1;
286}
287
288/*********************************************************************
289 Simple wrapper for a DNS query
290*********************************************************************/
291
292#define DNS_FAILED_WAITTIME 30
293
294static NTSTATUS dns_send_req( TALLOC_CTX *ctx, const char *name, int q_type,
295 uint8_t **buf, int *resp_length )
296{
297 uint8_t *buffer = NULL;
298 size_t buf_len = 0;
299 int resp_len = NS_PACKETSZ;
300 static time_t last_dns_check = 0;
301 static NTSTATUS last_dns_status = NT_STATUS_OK;
302 time_t now = time_mono(NULL);
303
304 /* Try to prevent bursts of DNS lookups if the server is down */
305
306 /* Protect against large clock changes */
307
308 if ( last_dns_check > now )
309 last_dns_check = 0;
310
311 /* IF we had a DNS timeout or a bad server and we are still
312 in the 30 second cache window, just return the previous
313 status and save the network timeout. */
314
315 if ( (NT_STATUS_EQUAL(last_dns_status,NT_STATUS_IO_TIMEOUT) ||
316 NT_STATUS_EQUAL(last_dns_status,NT_STATUS_CONNECTION_REFUSED)) &&
317 (last_dns_check+DNS_FAILED_WAITTIME) > now )
318 {
319 DEBUG(10,("dns_send_req: last dns check returning cached status (%s)\n",
320 nt_errstr(last_dns_status) ));
321 return last_dns_status;
322 }
323
324 /* Send the Query */
325 do {
326 if ( buffer )
327 TALLOC_FREE( buffer );
328
329 buf_len = resp_len * sizeof(uint8_t);
330
331 if (buf_len) {
332 if ((buffer = talloc_array(ctx, uint8_t, buf_len))
333 == NULL ) {
334 DEBUG(0,("dns_send_req: "
335 "talloc() failed!\n"));
336 last_dns_status = NT_STATUS_NO_MEMORY;
337 last_dns_check = time_mono(NULL);
338 return last_dns_status;
339 }
340 }
341
342 if ((resp_len = res_query(name, C_IN, q_type, buffer, buf_len))
343 < 0 ) {
344 DEBUG(3,("dns_send_req: "
345 "Failed to resolve %s (%s)\n",
346 name, strerror(errno)));
347 TALLOC_FREE( buffer );
348 last_dns_status = NT_STATUS_UNSUCCESSFUL;
349
350 if (errno == ETIMEDOUT) {
351 last_dns_status = NT_STATUS_IO_TIMEOUT;
352 }
353 if (errno == ECONNREFUSED) {
354 last_dns_status = NT_STATUS_CONNECTION_REFUSED;
355 }
356 last_dns_check = time_mono(NULL);
357 return last_dns_status;
358 }
359
360 /* On AIX, Solaris, and possibly some older glibc systems (e.g. SLES8)
361 truncated replies never give back a resp_len > buflen
362 which ends up causing DNS resolve failures on large tcp DNS replies */
363
364 if (buf_len == resp_len) {
365 if (resp_len == MAX_DNS_PACKET_SIZE) {
366 DEBUG(1,("dns_send_req: DNS reply too large when resolving %s\n",
367 name));
368 TALLOC_FREE( buffer );
369 last_dns_status = NT_STATUS_BUFFER_TOO_SMALL;
370 last_dns_check = time_mono(NULL);
371 return last_dns_status;
372 }
373
374 resp_len = MIN(resp_len*2, MAX_DNS_PACKET_SIZE);
375 }
376
377
378 } while ( buf_len < resp_len && resp_len <= MAX_DNS_PACKET_SIZE );
379
380 *buf = buffer;
381 *resp_length = resp_len;
382
383 last_dns_check = time_mono(NULL);
384 last_dns_status = NT_STATUS_OK;
385 return last_dns_status;
386}
387
388/*********************************************************************
389 Simple wrapper for a DNS SRV query
390*********************************************************************/
391
392NTSTATUS ads_dns_lookup_srv(TALLOC_CTX *ctx,
393 const char *name,
394 struct dns_rr_srv **dclist,
395 int *numdcs)
396{
397 uint8_t *buffer = NULL;
398 int resp_len = 0;
399 struct dns_rr_srv *dcs = NULL;
400 int query_count, answer_count, auth_count, additional_count;
401 uint8_t *p = buffer;
402 int rrnum;
403 int idx = 0;
404 NTSTATUS status;
405
406 if ( !ctx || !name || !dclist ) {
407 return NT_STATUS_INVALID_PARAMETER;
408 }
409
410 /* Send the request. May have to loop several times in case
411 of large replies */
412
413 status = dns_send_req( ctx, name, T_SRV, &buffer, &resp_len );
414 if ( !NT_STATUS_IS_OK(status) ) {
415 DEBUG(3,("ads_dns_lookup_srv: Failed to send DNS query (%s)\n",
416 nt_errstr(status)));
417 return status;
418 }
419 p = buffer;
420
421 /* For some insane reason, the ns_initparse() et. al. routines are only
422 available in libresolv.a, and not the shared lib. Who knows why....
423 So we have to parse the DNS reply ourselves */
424
425 /* Pull the answer RR's count from the header.
426 * Use the NMB ordering macros */
427
428 query_count = RSVAL( p, 4 );
429 answer_count = RSVAL( p, 6 );
430 auth_count = RSVAL( p, 8 );
431 additional_count = RSVAL( p, 10 );
432
433 DEBUG(4,("ads_dns_lookup_srv: "
434 "%d records returned in the answer section.\n",
435 answer_count));
436
437 if (answer_count) {
438 if ((dcs = talloc_zero_array(ctx, struct dns_rr_srv,
439 answer_count)) == NULL ) {
440 DEBUG(0,("ads_dns_lookup_srv: "
441 "talloc() failure for %d char*'s\n",
442 answer_count));
443 return NT_STATUS_NO_MEMORY;
444 }
445 } else {
446 dcs = NULL;
447 }
448
449 /* now skip the header */
450
451 p += NS_HFIXEDSZ;
452
453 /* parse the query section */
454
455 for ( rrnum=0; rrnum<query_count; rrnum++ ) {
456 struct dns_query q;
457
458 if (!ads_dns_parse_query(ctx, buffer,
459 buffer+resp_len, &p, &q)) {
460 DEBUG(1,("ads_dns_lookup_srv: "
461 "Failed to parse query record [%d]!\n", rrnum));
462 return NT_STATUS_UNSUCCESSFUL;
463 }
464 }
465
466 /* now we are at the answer section */
467
468 for ( rrnum=0; rrnum<answer_count; rrnum++ ) {
469 if (!ads_dns_parse_rr_srv(ctx, buffer, buffer+resp_len,
470 &p, &dcs[rrnum])) {
471 DEBUG(1,("ads_dns_lookup_srv: "
472 "Failed to parse answer recordi [%d]!\n", rrnum));
473 return NT_STATUS_UNSUCCESSFUL;
474 }
475 }
476 idx = rrnum;
477
478 /* Parse the authority section */
479 /* just skip these for now */
480
481 for ( rrnum=0; rrnum<auth_count; rrnum++ ) {
482 struct dns_rr rr;
483
484 if (!ads_dns_parse_rr( ctx, buffer,
485 buffer+resp_len, &p, &rr)) {
486 DEBUG(1,("ads_dns_lookup_srv: "
487 "Failed to parse authority record! [%d]\n", rrnum));
488 return NT_STATUS_UNSUCCESSFUL;
489 }
490 }
491
492 /* Parse the additional records section */
493
494 for ( rrnum=0; rrnum<additional_count; rrnum++ ) {
495 struct dns_rr rr;
496 int i;
497
498 if (!ads_dns_parse_rr(ctx, buffer, buffer+resp_len,
499 &p, &rr)) {
500 DEBUG(1,("ads_dns_lookup_srv: Failed "
501 "to parse additional records section! [%d]\n", rrnum));
502 return NT_STATUS_UNSUCCESSFUL;
503 }
504
505 /* Only interested in A or AAAA records as a shortcut for having
506 * to come back later and lookup the name. For multi-homed
507 * hosts, the number of additional records and exceed the
508 * number of answer records. */
509
510 if (rr.type != T_A || rr.rdatalen != 4) {
511#if defined(HAVE_IPV6)
512 /* RFC2874 defines A6 records. This
513 * requires recusive and horribly complex lookups.
514 * Bastards. Ignore this for now.... JRA.
515 * Luckily RFC3363 reprecates A6 records.
516 */
517 if (rr.type != T_AAAA || rr.rdatalen != 16)
518#endif
519 continue;
520 }
521
522 for ( i=0; i<idx; i++ ) {
523 if ( strcmp( rr.hostname, dcs[i].hostname ) == 0 ) {
524 int num_ips = dcs[i].num_ips;
525 struct sockaddr_storage *tmp_ss_s;
526
527 /* allocate new memory */
528
529 if (dcs[i].num_ips == 0) {
530 if ((dcs[i].ss_s = talloc_array(dcs,
531 struct sockaddr_storage, 1 ))
532 == NULL ) {
533 return NT_STATUS_NO_MEMORY;
534 }
535 } else {
536 if ((tmp_ss_s = talloc_realloc(dcs,
537 dcs[i].ss_s,
538 struct sockaddr_storage,
539 dcs[i].num_ips+1))
540 == NULL ) {
541 return NT_STATUS_NO_MEMORY;
542 }
543
544 dcs[i].ss_s = tmp_ss_s;
545 }
546 dcs[i].num_ips++;
547
548 /* copy the new IP address */
549 if (rr.type == T_A) {
550 struct in_addr ip;
551 memcpy(&ip, rr.rdata, 4);
552 in_addr_to_sockaddr_storage(
553 &dcs[i].ss_s[num_ips],
554 ip);
555 }
556#if defined(HAVE_IPV6)
557 if (rr.type == T_AAAA) {
558 struct in6_addr ip6;
559 memcpy(&ip6, rr.rdata, rr.rdatalen);
560 in6_addr_to_sockaddr_storage(
561 &dcs[i].ss_s[num_ips],
562 ip6);
563 }
564#endif
565 }
566 }
567 }
568
569 TYPESAFE_QSORT(dcs, idx, dnssrvcmp );
570
571 *dclist = dcs;
572 *numdcs = idx;
573
574 return NT_STATUS_OK;
575}
576
577/*********************************************************************
578 Simple wrapper for a DNS NS query
579*********************************************************************/
580
581NTSTATUS ads_dns_lookup_ns(TALLOC_CTX *ctx,
582 const char *dnsdomain,
583 struct dns_rr_ns **nslist,
584 int *numns)
585{
586 uint8_t *buffer = NULL;
587 int resp_len = 0;
588 struct dns_rr_ns *nsarray = NULL;
589 int query_count, answer_count, auth_count, additional_count;
590 uint8_t *p;
591 int rrnum;
592 int idx = 0;
593 NTSTATUS status;
594
595 if ( !ctx || !dnsdomain || !nslist ) {
596 return NT_STATUS_INVALID_PARAMETER;
597 }
598
599 /* Send the request. May have to loop several times in case
600 of large replies */
601
602 status = dns_send_req( ctx, dnsdomain, T_NS, &buffer, &resp_len );
603 if ( !NT_STATUS_IS_OK(status) ) {
604 DEBUG(3,("ads_dns_lookup_ns: Failed to send DNS query (%s)\n",
605 nt_errstr(status)));
606 return status;
607 }
608 p = buffer;
609
610 /* For some insane reason, the ns_initparse() et. al. routines are only
611 available in libresolv.a, and not the shared lib. Who knows why....
612 So we have to parse the DNS reply ourselves */
613
614 /* Pull the answer RR's count from the header.
615 * Use the NMB ordering macros */
616
617 query_count = RSVAL( p, 4 );
618 answer_count = RSVAL( p, 6 );
619 auth_count = RSVAL( p, 8 );
620 additional_count = RSVAL( p, 10 );
621
622 DEBUG(4,("ads_dns_lookup_ns: "
623 "%d records returned in the answer section.\n",
624 answer_count));
625
626 if (answer_count) {
627 if ((nsarray = talloc_array(ctx, struct dns_rr_ns,
628 answer_count)) == NULL ) {
629 DEBUG(0,("ads_dns_lookup_ns: "
630 "talloc() failure for %d char*'s\n",
631 answer_count));
632 return NT_STATUS_NO_MEMORY;
633 }
634 } else {
635 nsarray = NULL;
636 }
637
638 /* now skip the header */
639
640 p += NS_HFIXEDSZ;
641
642 /* parse the query section */
643
644 for ( rrnum=0; rrnum<query_count; rrnum++ ) {
645 struct dns_query q;
646
647 if (!ads_dns_parse_query(ctx, buffer, buffer+resp_len,
648 &p, &q)) {
649 DEBUG(1,("ads_dns_lookup_ns: "
650 " Failed to parse query record!\n"));
651 return NT_STATUS_UNSUCCESSFUL;
652 }
653 }
654
655 /* now we are at the answer section */
656
657 for ( rrnum=0; rrnum<answer_count; rrnum++ ) {
658 if (!ads_dns_parse_rr_ns(ctx, buffer, buffer+resp_len,
659 &p, &nsarray[rrnum])) {
660 DEBUG(1,("ads_dns_lookup_ns: "
661 "Failed to parse answer record!\n"));
662 return NT_STATUS_UNSUCCESSFUL;
663 }
664 }
665 idx = rrnum;
666
667 /* Parse the authority section */
668 /* just skip these for now */
669
670 for ( rrnum=0; rrnum<auth_count; rrnum++ ) {
671 struct dns_rr rr;
672
673 if ( !ads_dns_parse_rr(ctx, buffer, buffer+resp_len,
674 &p, &rr)) {
675 DEBUG(1,("ads_dns_lookup_ns: "
676 "Failed to parse authority record!\n"));
677 return NT_STATUS_UNSUCCESSFUL;
678 }
679 }
680
681 /* Parse the additional records section */
682
683 for ( rrnum=0; rrnum<additional_count; rrnum++ ) {
684 struct dns_rr rr;
685 int i;
686
687 if (!ads_dns_parse_rr(ctx, buffer, buffer+resp_len,
688 &p, &rr)) {
689 DEBUG(1,("ads_dns_lookup_ns: Failed "
690 "to parse additional records section!\n"));
691 return NT_STATUS_UNSUCCESSFUL;
692 }
693
694 /* only interested in A records as a shortcut for having to come
695 back later and lookup the name */
696
697 if (rr.type != T_A || rr.rdatalen != 4) {
698#if defined(HAVE_IPV6)
699 if (rr.type != T_AAAA || rr.rdatalen != 16)
700#endif
701 continue;
702 }
703
704 for ( i=0; i<idx; i++ ) {
705 if (strcmp(rr.hostname, nsarray[i].hostname) == 0) {
706 if (rr.type == T_A) {
707 struct in_addr ip;
708 memcpy(&ip, rr.rdata, 4);
709 in_addr_to_sockaddr_storage(
710 &nsarray[i].ss,
711 ip);
712 }
713#if defined(HAVE_IPV6)
714 if (rr.type == T_AAAA) {
715 struct in6_addr ip6;
716 memcpy(&ip6, rr.rdata, rr.rdatalen);
717 in6_addr_to_sockaddr_storage(
718 &nsarray[i].ss,
719 ip6);
720 }
721#endif
722 }
723 }
724 }
725
726 *nslist = nsarray;
727 *numns = idx;
728
729 return NT_STATUS_OK;
730}
731
732/********************************************************************
733 Query with optional sitename.
734********************************************************************/
735
736static NTSTATUS ads_dns_query_internal(TALLOC_CTX *ctx,
737 const char *servicename,
738 const char *dc_pdc_gc_domains,
739 const char *realm,
740 const char *sitename,
741 struct dns_rr_srv **dclist,
742 int *numdcs )
743{
744 char *name;
745 if (sitename && strlen(sitename)) {
746 name = talloc_asprintf(ctx, "%s._tcp.%s._sites.%s._msdcs.%s",
747 servicename, sitename,
748 dc_pdc_gc_domains, realm);
749 } else {
750 name = talloc_asprintf(ctx, "%s._tcp.%s._msdcs.%s",
751 servicename, dc_pdc_gc_domains, realm);
752 }
753 if (!name) {
754 return NT_STATUS_NO_MEMORY;
755 }
756 return ads_dns_lookup_srv(ctx, name, dclist, numdcs);
757}
758
759/********************************************************************
760 Query for AD DC's.
761********************************************************************/
762
763NTSTATUS ads_dns_query_dcs(TALLOC_CTX *ctx,
764 const char *realm,
765 const char *sitename,
766 struct dns_rr_srv **dclist,
767 int *numdcs )
768{
769 NTSTATUS status;
770
771 status = ads_dns_query_internal(ctx,
772 "_ldap",
773 "dc",
774 realm,
775 sitename,
776 dclist,
777 numdcs);
778
779 if (NT_STATUS_EQUAL(status, NT_STATUS_IO_TIMEOUT) ||
780 NT_STATUS_EQUAL(status, NT_STATUS_CONNECTION_REFUSED)) {
781 return status;
782 }
783
784 if (sitename &&
785 ((!NT_STATUS_IS_OK(status)) ||
786 (NT_STATUS_IS_OK(status) && (numdcs == 0)))) {
787 /* Sitename DNS query may have failed. Try without. */
788 status = ads_dns_query_internal(ctx,
789 "_ldap",
790 "dc",
791 realm,
792 NULL,
793 dclist,
794 numdcs);
795 }
796 return status;
797}
798
799/********************************************************************
800 Query for AD GC's.
801********************************************************************/
802
803NTSTATUS ads_dns_query_gcs(TALLOC_CTX *ctx,
804 const char *realm,
805 const char *sitename,
806 struct dns_rr_srv **dclist,
807 int *numdcs )
808{
809 NTSTATUS status;
810
811 status = ads_dns_query_internal(ctx,
812 "_ldap",
813 "gc",
814 realm,
815 sitename,
816 dclist,
817 numdcs);
818
819 if (NT_STATUS_EQUAL(status, NT_STATUS_IO_TIMEOUT) ||
820 NT_STATUS_EQUAL(status, NT_STATUS_CONNECTION_REFUSED)) {
821 return status;
822 }
823
824 if (sitename &&
825 ((!NT_STATUS_IS_OK(status)) ||
826 (NT_STATUS_IS_OK(status) && (numdcs == 0)))) {
827 /* Sitename DNS query may have failed. Try without. */
828 status = ads_dns_query_internal(ctx,
829 "_ldap",
830 "gc",
831 realm,
832 NULL,
833 dclist,
834 numdcs);
835 }
836 return status;
837}
838
839/********************************************************************
840 Query for AD KDC's.
841 Even if our underlying kerberos libraries are UDP only, this
842 is pretty safe as it's unlikely that a KDC supports TCP and not UDP.
843********************************************************************/
844
845NTSTATUS ads_dns_query_kdcs(TALLOC_CTX *ctx,
846 const char *dns_forest_name,
847 const char *sitename,
848 struct dns_rr_srv **dclist,
849 int *numdcs )
850{
851 NTSTATUS status;
852
853 status = ads_dns_query_internal(ctx,
854 "_kerberos",
855 "dc",
856 dns_forest_name,
857 sitename,
858 dclist,
859 numdcs);
860
861 if (NT_STATUS_EQUAL(status, NT_STATUS_IO_TIMEOUT) ||
862 NT_STATUS_EQUAL(status, NT_STATUS_CONNECTION_REFUSED)) {
863 return status;
864 }
865
866 if (sitename &&
867 ((!NT_STATUS_IS_OK(status)) ||
868 (NT_STATUS_IS_OK(status) && (numdcs == 0)))) {
869 /* Sitename DNS query may have failed. Try without. */
870 status = ads_dns_query_internal(ctx,
871 "_kerberos",
872 "dc",
873 dns_forest_name,
874 NULL,
875 dclist,
876 numdcs);
877 }
878 return status;
879}
880
881/********************************************************************
882 Query for AD PDC. Sitename is obsolete here.
883********************************************************************/
884
885NTSTATUS ads_dns_query_pdc(TALLOC_CTX *ctx,
886 const char *dns_domain_name,
887 struct dns_rr_srv **dclist,
888 int *numdcs )
889{
890 return ads_dns_query_internal(ctx,
891 "_ldap",
892 "pdc",
893 dns_domain_name,
894 NULL,
895 dclist,
896 numdcs);
897}
898
899/********************************************************************
900 Query for AD DC by guid. Sitename is obsolete here.
901********************************************************************/
902
903NTSTATUS ads_dns_query_dcs_guid(TALLOC_CTX *ctx,
904 const char *dns_forest_name,
905 const char *domain_guid,
906 struct dns_rr_srv **dclist,
907 int *numdcs )
908{
909 /*_ldap._tcp.DomainGuid.domains._msdcs.DnsForestName */
910
911 const char *domains;
912
913 /* little hack */
914 domains = talloc_asprintf(ctx, "%s.domains", domain_guid);
915 if (!domains) {
916 return NT_STATUS_NO_MEMORY;
917 }
918
919 return ads_dns_query_internal(ctx,
920 "_ldap",
921 domains,
922 dns_forest_name,
923 NULL,
924 dclist,
925 numdcs);
926}
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