source: branches/samba-3.5.x/source3/libads/dns.c@ 1075

Last change on this file since 1075 was 414, checked in by Herwig Bauernfeind, 15 years ago

Samba 3.5.0: Initial import
File size: 25.0 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
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
49#if defined(HAVE_IPV6)
50#if !defined(T_AAAA)
51# define T_AAAA ns_t_aaaa
52#endif
53#endif
54
55# define T_SRV ns_t_srv
56#if !defined(T_NS) /* AIX 5.3 already defines T_NS */
57# define T_NS ns_t_ns
58#endif
59#else
60# ifdef HFIXEDSZ
61# define NS_HFIXEDSZ HFIXEDSZ
62# else
63# define NS_HFIXEDSZ sizeof(HEADER)
64# endif /* HFIXEDSZ */
65# ifdef PACKETSZ
66# define NS_PACKETSZ PACKETSZ
67# else /* 512 is usually the default */
68# define NS_PACKETSZ 512
69# endif /* PACKETSZ */
70# define T_SRV 33
71#endif
72
73/*********************************************************************
74*********************************************************************/
75
76static bool ads_dns_parse_query( TALLOC_CTX *ctx, uint8 *start, uint8 *end,
77 uint8 **ptr, struct dns_query *q )
78{
79 uint8 *p = *ptr;
80 char hostname[MAX_DNS_NAME_LENGTH];
81 int namelen;
82
83 ZERO_STRUCTP( q );
84
85 if ( !start || !end || !q || !*ptr)
86 return False;
87
88 /* See RFC 1035 for details. If this fails, then return. */
89
90 namelen = dn_expand( start, end, p, hostname, sizeof(hostname) );
91 if ( namelen < 0 ) {
92 return False;
93 }
94 p += namelen;
95 q->hostname = talloc_strdup( ctx, hostname );
96
97 /* check that we have space remaining */
98
99 if ( PTR_DIFF(p+4, end) > 0 )
100 return False;
101
102 q->type = RSVAL( p, 0 );
103 q->in_class = RSVAL( p, 2 );
104 p += 4;
105
106 *ptr = p;
107
108 return True;
109}
110
111/*********************************************************************
112*********************************************************************/
113
114static bool ads_dns_parse_rr( TALLOC_CTX *ctx, uint8 *start, uint8 *end,
115 uint8 **ptr, struct dns_rr *rr )
116{
117 uint8 *p = *ptr;
118 char hostname[MAX_DNS_NAME_LENGTH];
119 int namelen;
120
121 if ( !start || !end || !rr || !*ptr)
122 return -1;
123
124 ZERO_STRUCTP( rr );
125 /* pull the name from the answer */
126
127 namelen = dn_expand( start, end, p, hostname, sizeof(hostname) );
128 if ( namelen < 0 ) {
129 return -1;
130 }
131 p += namelen;
132 rr->hostname = talloc_strdup( ctx, hostname );
133
134 /* check that we have space remaining */
135
136 if ( PTR_DIFF(p+10, end) > 0 )
137 return False;
138
139 /* pull some values and then skip onto the string */
140
141 rr->type = RSVAL(p, 0);
142 rr->in_class = RSVAL(p, 2);
143 rr->ttl = RIVAL(p, 4);
144 rr->rdatalen = RSVAL(p, 8);
145
146 p += 10;
147
148 /* sanity check the available space */
149
150 if ( PTR_DIFF(p+rr->rdatalen, end ) > 0 ) {
151 return False;
152
153 }
154
155 /* save a point to the rdata for this section */
156
157 rr->rdata = p;
158 p += rr->rdatalen;
159
160 *ptr = p;
161
162 return True;
163}
164
165/*********************************************************************
166*********************************************************************/
167
168static bool ads_dns_parse_rr_srv( TALLOC_CTX *ctx, uint8 *start, uint8 *end,
169 uint8 **ptr, struct dns_rr_srv *srv )
170{
171 struct dns_rr rr;
172 uint8 *p;
173 char dcname[MAX_DNS_NAME_LENGTH];
174 int namelen;
175
176 if ( !start || !end || !srv || !*ptr)
177 return -1;
178
179 /* Parse the RR entry. Coming out of the this, ptr is at the beginning
180 of the next record */
181
182 if ( !ads_dns_parse_rr( ctx, start, end, ptr, &rr ) ) {
183 DEBUG(1,("ads_dns_parse_rr_srv: Failed to parse RR record\n"));
184 return False;
185 }
186
187 if ( rr.type != T_SRV ) {
188 DEBUG(1,("ads_dns_parse_rr_srv: Bad answer type (%d)\n",
189 rr.type));
190 return False;
191 }
192
193 p = rr.rdata;
194
195 srv->priority = RSVAL(p, 0);
196 srv->weight = RSVAL(p, 2);
197 srv->port = RSVAL(p, 4);
198
199 p += 6;
200
201 namelen = dn_expand( start, end, p, dcname, sizeof(dcname) );
202 if ( namelen < 0 ) {
203 DEBUG(1,("ads_dns_parse_rr_srv: Failed to uncompress name!\n"));
204 return False;
205 }
206
207 srv->hostname = talloc_strdup( ctx, dcname );
208
209 DEBUG(10,("ads_dns_parse_rr_srv: Parsed %s [%u, %u, %u]\n",
210 srv->hostname,
211 srv->priority,
212 srv->weight,
213 srv->port));
214
215 return True;
216}
217
218/*********************************************************************
219*********************************************************************/
220
221static bool ads_dns_parse_rr_ns( TALLOC_CTX *ctx, uint8 *start, uint8 *end,
222 uint8 **ptr, struct dns_rr_ns *nsrec )
223{
224 struct dns_rr rr;
225 uint8 *p;
226 char nsname[MAX_DNS_NAME_LENGTH];
227 int namelen;
228
229 if ( !start || !end || !nsrec || !*ptr)
230 return -1;
231
232 /* Parse the RR entry. Coming out of the this, ptr is at the beginning
233 of the next record */
234
235 if ( !ads_dns_parse_rr( ctx, start, end, ptr, &rr ) ) {
236 DEBUG(1,("ads_dns_parse_rr_ns: Failed to parse RR record\n"));
237 return False;
238 }
239
240 if ( rr.type != T_NS ) {
241 DEBUG(1,("ads_dns_parse_rr_ns: Bad answer type (%d)\n",
242 rr.type));
243 return False;
244 }
245
246 p = rr.rdata;
247
248 /* ame server hostname */
249
250 namelen = dn_expand( start, end, p, nsname, sizeof(nsname) );
251 if ( namelen < 0 ) {
252 DEBUG(1,("ads_dns_parse_rr_ns: Failed to uncompress name!\n"));
253 return False;
254 }
255 nsrec->hostname = talloc_strdup( ctx, nsname );
256
257 return True;
258}
259
260/*********************************************************************
261 Sort SRV record list based on weight and priority. See RFC 2782.
262*********************************************************************/
263
264static int dnssrvcmp( struct dns_rr_srv *a, struct dns_rr_srv *b )
265{
266 if ( a->priority == b->priority ) {
267
268 /* randomize entries with an equal weight and priority */
269 if ( a->weight == b->weight )
270 return 0;
271
272 /* higher weights should be sorted lower */
273 if ( a->weight > b->weight )
274 return -1;
275 else
276 return 1;
277 }
278
279 if ( a->priority < b->priority )
280 return -1;
281
282 return 1;
283}
284
285/*********************************************************************
286 Simple wrapper for a DNS query
287*********************************************************************/
288
289#define DNS_FAILED_WAITTIME 30
290
291static NTSTATUS dns_send_req( TALLOC_CTX *ctx, const char *name, int q_type,
292 uint8 **buf, int *resp_length )
293{
294 uint8 *buffer = NULL;
295 size_t buf_len = 0;
296 int resp_len = NS_PACKETSZ;
297 static time_t last_dns_check = 0;
298 static NTSTATUS last_dns_status = NT_STATUS_OK;
299 time_t now = time(NULL);
300
301 /* Try to prevent bursts of DNS lookups if the server is down */
302
303 /* Protect against large clock changes */
304
305 if ( last_dns_check > now )
306 last_dns_check = 0;
307
308 /* IF we had a DNS timeout or a bad server and we are still
309 in the 30 second cache window, just return the previous
310 status and save the network timeout. */
311
312 if ( (NT_STATUS_EQUAL(last_dns_status,NT_STATUS_IO_TIMEOUT) ||
313 NT_STATUS_EQUAL(last_dns_status,NT_STATUS_CONNECTION_REFUSED)) &&
314 (last_dns_check+DNS_FAILED_WAITTIME) > now )
315 {
316 DEBUG(10,("last_dns_check: Returning cached status (%s)\n",
317 nt_errstr(last_dns_status) ));
318 return last_dns_status;
319 }
320
321 /* Send the Query */
322 do {
323 if ( buffer )
324 TALLOC_FREE( buffer );
325
326 buf_len = resp_len * sizeof(uint8);
327
328 if (buf_len) {
329 if ((buffer = TALLOC_ARRAY(ctx, uint8, buf_len))
330 == NULL ) {
331 DEBUG(0,("ads_dns_lookup_srv: "
332 "talloc() failed!\n"));
333 last_dns_status = NT_STATUS_NO_MEMORY;
334 last_dns_check = time(NULL);
335 return last_dns_status;
336 }
337 }
338
339 if ((resp_len = res_query(name, C_IN, q_type, buffer, buf_len))
340 < 0 ) {
341 DEBUG(3,("ads_dns_lookup_srv: "
342 "Failed to resolve %s (%s)\n",
343 name, strerror(errno)));
344 TALLOC_FREE( buffer );
345 last_dns_status = NT_STATUS_UNSUCCESSFUL;
346
347 if (errno == ETIMEDOUT) {
348 last_dns_status = NT_STATUS_IO_TIMEOUT;
349 }
350 if (errno == ECONNREFUSED) {
351 last_dns_status = NT_STATUS_CONNECTION_REFUSED;
352 }
353 last_dns_check = time(NULL);
354 return last_dns_status;
355 }
356
357 /* On AIX, Solaris, and possibly some older glibc systems (e.g. SLES8)
358 truncated replies never give back a resp_len > buflen
359 which ends up causing DNS resolve failures on large tcp DNS replies */
360
361 if (buf_len == resp_len) {
362 if (resp_len == MAX_DNS_PACKET_SIZE) {
363 DEBUG(1,("dns_send_req: DNS reply too large when resolving %s\n",
364 name));
365 TALLOC_FREE( buffer );
366 last_dns_status = NT_STATUS_BUFFER_TOO_SMALL;
367 last_dns_check = time(NULL);
368 return last_dns_status;
369 }
370
371 resp_len = MIN(resp_len*2, MAX_DNS_PACKET_SIZE);
372 }
373
374
375 } while ( buf_len < resp_len && resp_len <= MAX_DNS_PACKET_SIZE );
376
377 *buf = buffer;
378 *resp_length = resp_len;
379
380 last_dns_check = time(NULL);
381 last_dns_status = NT_STATUS_OK;
382 return last_dns_status;
383}
384
385/*********************************************************************
386 Simple wrapper for a DNS SRV query
387*********************************************************************/
388
389static NTSTATUS ads_dns_lookup_srv( TALLOC_CTX *ctx,
390 const char *name,
391 struct dns_rr_srv **dclist,
392 int *numdcs)
393{
394 uint8 *buffer = NULL;
395 int resp_len = 0;
396 struct dns_rr_srv *dcs = NULL;
397 int query_count, answer_count, auth_count, additional_count;
398 uint8 *p = buffer;
399 int rrnum;
400 int idx = 0;
401 NTSTATUS status;
402
403 if ( !ctx || !name || !dclist ) {
404 return NT_STATUS_INVALID_PARAMETER;
405 }
406
407 /* Send the request. May have to loop several times in case
408 of large replies */
409
410 status = dns_send_req( ctx, name, T_SRV, &buffer, &resp_len );
411 if ( !NT_STATUS_IS_OK(status) ) {
412 DEBUG(3,("ads_dns_lookup_srv: Failed to send DNS query (%s)\n",
413 nt_errstr(status)));
414 return status;
415 }
416 p = buffer;
417
418 /* For some insane reason, the ns_initparse() et. al. routines are only
419 available in libresolv.a, and not the shared lib. Who knows why....
420 So we have to parse the DNS reply ourselves */
421
422 /* Pull the answer RR's count from the header.
423 * Use the NMB ordering macros */
424
425 query_count = RSVAL( p, 4 );
426 answer_count = RSVAL( p, 6 );
427 auth_count = RSVAL( p, 8 );
428 additional_count = RSVAL( p, 10 );
429
430 DEBUG(4,("ads_dns_lookup_srv: "
431 "%d records returned in the answer section.\n",
432 answer_count));
433
434 if (answer_count) {
435 if ((dcs = TALLOC_ZERO_ARRAY(ctx, struct dns_rr_srv,
436 answer_count)) == NULL ) {
437 DEBUG(0,("ads_dns_lookup_srv: "
438 "talloc() failure for %d char*'s\n",
439 answer_count));
440 return NT_STATUS_NO_MEMORY;
441 }
442 } else {
443 dcs = NULL;
444 }
445
446 /* now skip the header */
447
448 p += NS_HFIXEDSZ;
449
450 /* parse the query section */
451
452 for ( rrnum=0; rrnum<query_count; rrnum++ ) {
453 struct dns_query q;
454
455 if (!ads_dns_parse_query(ctx, buffer,
456 buffer+resp_len, &p, &q)) {
457 DEBUG(1,("ads_dns_lookup_srv: "
458 "Failed to parse query record [%d]!\n", rrnum));
459 return NT_STATUS_UNSUCCESSFUL;
460 }
461 }
462
463 /* now we are at the answer section */
464
465 for ( rrnum=0; rrnum<answer_count; rrnum++ ) {
466 if (!ads_dns_parse_rr_srv(ctx, buffer, buffer+resp_len,
467 &p, &dcs[rrnum])) {
468 DEBUG(1,("ads_dns_lookup_srv: "
469 "Failed to parse answer recordi [%d]!\n", rrnum));
470 return NT_STATUS_UNSUCCESSFUL;
471 }
472 }
473 idx = rrnum;
474
475 /* Parse the authority section */
476 /* just skip these for now */
477
478 for ( rrnum=0; rrnum<auth_count; rrnum++ ) {
479 struct dns_rr rr;
480
481 if (!ads_dns_parse_rr( ctx, buffer,
482 buffer+resp_len, &p, &rr)) {
483 DEBUG(1,("ads_dns_lookup_srv: "
484 "Failed to parse authority record! [%d]\n", rrnum));
485 return NT_STATUS_UNSUCCESSFUL;
486 }
487 }
488
489 /* Parse the additional records section */
490
491 for ( rrnum=0; rrnum<additional_count; rrnum++ ) {
492 struct dns_rr rr;
493 int i;
494
495 if (!ads_dns_parse_rr(ctx, buffer, buffer+resp_len,
496 &p, &rr)) {
497 DEBUG(1,("ads_dns_lookup_srv: Failed "
498 "to parse additional records section! [%d]\n", rrnum));
499 return NT_STATUS_UNSUCCESSFUL;
500 }
501
502 /* Only interested in A or AAAA records as a shortcut for having
503 * to come back later and lookup the name. For multi-homed
504 * hosts, the number of additional records and exceed the
505 * number of answer records. */
506
507 if (rr.type != T_A || rr.rdatalen != 4) {
508#if defined(HAVE_IPV6)
509 /* RFC2874 defines A6 records. This
510 * requires recusive and horribly complex lookups.
511 * Bastards. Ignore this for now.... JRA.
512 * Luckily RFC3363 reprecates A6 records.
513 */
514 if (rr.type != T_AAAA || rr.rdatalen != 16)
515#endif
516 continue;
517 }
518
519 for ( i=0; i<idx; i++ ) {
520 if ( strcmp( rr.hostname, dcs[i].hostname ) == 0 ) {
521 int num_ips = dcs[i].num_ips;
522 struct sockaddr_storage *tmp_ss_s;
523
524 /* allocate new memory */
525
526 if (dcs[i].num_ips == 0) {
527 if ((dcs[i].ss_s = TALLOC_ARRAY(dcs,
528 struct sockaddr_storage, 1 ))
529 == NULL ) {
530 return NT_STATUS_NO_MEMORY;
531 }
532 } else {
533 if ((tmp_ss_s = TALLOC_REALLOC_ARRAY(dcs,
534 dcs[i].ss_s,
535 struct sockaddr_storage,
536 dcs[i].num_ips+1))
537 == NULL ) {
538 return NT_STATUS_NO_MEMORY;
539 }
540
541 dcs[i].ss_s = tmp_ss_s;
542 }
543 dcs[i].num_ips++;
544
545 /* copy the new IP address */
546 if (rr.type == T_A) {
547 struct in_addr ip;
548 memcpy(&ip, rr.rdata, 4);
549 in_addr_to_sockaddr_storage(
550 &dcs[i].ss_s[num_ips],
551 ip);
552 }
553#if defined(HAVE_IPV6)
554 if (rr.type == T_AAAA) {
555 struct in6_addr ip6;
556 memcpy(&ip6, rr.rdata, rr.rdatalen);
557 in6_addr_to_sockaddr_storage(
558 &dcs[i].ss_s[num_ips],
559 ip6);
560 }
561#endif
562 }
563 }
564 }
565
566 qsort( dcs, idx, sizeof(struct dns_rr_srv), QSORT_CAST dnssrvcmp );
567
568 *dclist = dcs;
569 *numdcs = idx;
570
571 return NT_STATUS_OK;
572}
573
574/*********************************************************************
575 Simple wrapper for a DNS NS query
576*********************************************************************/
577
578NTSTATUS ads_dns_lookup_ns(TALLOC_CTX *ctx,
579 const char *dnsdomain,
580 struct dns_rr_ns **nslist,
581 int *numns)
582{
583 uint8 *buffer = NULL;
584 int resp_len = 0;
585 struct dns_rr_ns *nsarray = NULL;
586 int query_count, answer_count, auth_count, additional_count;
587 uint8 *p;
588 int rrnum;
589 int idx = 0;
590 NTSTATUS status;
591
592 if ( !ctx || !dnsdomain || !nslist ) {
593 return NT_STATUS_INVALID_PARAMETER;
594 }
595
596 /* Send the request. May have to loop several times in case
597 of large replies */
598
599 status = dns_send_req( ctx, dnsdomain, T_NS, &buffer, &resp_len );
600 if ( !NT_STATUS_IS_OK(status) ) {
601 DEBUG(3,("ads_dns_lookup_ns: Failed to send DNS query (%s)\n",
602 nt_errstr(status)));
603 return status;
604 }
605 p = buffer;
606
607 /* For some insane reason, the ns_initparse() et. al. routines are only
608 available in libresolv.a, and not the shared lib. Who knows why....
609 So we have to parse the DNS reply ourselves */
610
611 /* Pull the answer RR's count from the header.
612 * Use the NMB ordering macros */
613
614 query_count = RSVAL( p, 4 );
615 answer_count = RSVAL( p, 6 );
616 auth_count = RSVAL( p, 8 );
617 additional_count = RSVAL( p, 10 );
618
619 DEBUG(4,("ads_dns_lookup_ns: "
620 "%d records returned in the answer section.\n",
621 answer_count));
622
623 if (answer_count) {
624 if ((nsarray = TALLOC_ARRAY(ctx, struct dns_rr_ns,
625 answer_count)) == NULL ) {
626 DEBUG(0,("ads_dns_lookup_ns: "
627 "talloc() failure for %d char*'s\n",
628 answer_count));
629 return NT_STATUS_NO_MEMORY;
630 }
631 } else {
632 nsarray = NULL;
633 }
634
635 /* now skip the header */
636
637 p += NS_HFIXEDSZ;
638
639 /* parse the query section */
640
641 for ( rrnum=0; rrnum<query_count; rrnum++ ) {
642 struct dns_query q;
643
644 if (!ads_dns_parse_query(ctx, buffer, buffer+resp_len,
645 &p, &q)) {
646 DEBUG(1,("ads_dns_lookup_ns: "
647 " Failed to parse query record!\n"));
648 return NT_STATUS_UNSUCCESSFUL;
649 }
650 }
651
652 /* now we are at the answer section */
653
654 for ( rrnum=0; rrnum<answer_count; rrnum++ ) {
655 if (!ads_dns_parse_rr_ns(ctx, buffer, buffer+resp_len,
656 &p, &nsarray[rrnum])) {
657 DEBUG(1,("ads_dns_lookup_ns: "
658 "Failed to parse answer record!\n"));
659 return NT_STATUS_UNSUCCESSFUL;
660 }
661 }
662 idx = rrnum;
663
664 /* Parse the authority section */
665 /* just skip these for now */
666
667 for ( rrnum=0; rrnum<auth_count; rrnum++ ) {
668 struct dns_rr rr;
669
670 if ( !ads_dns_parse_rr(ctx, buffer, buffer+resp_len,
671 &p, &rr)) {
672 DEBUG(1,("ads_dns_lookup_ns: "
673 "Failed to parse authority record!\n"));
674 return NT_STATUS_UNSUCCESSFUL;
675 }
676 }
677
678 /* Parse the additional records section */
679
680 for ( rrnum=0; rrnum<additional_count; rrnum++ ) {
681 struct dns_rr rr;
682 int i;
683
684 if (!ads_dns_parse_rr(ctx, buffer, buffer+resp_len,
685 &p, &rr)) {
686 DEBUG(1,("ads_dns_lookup_ns: Failed "
687 "to parse additional records section!\n"));
688 return NT_STATUS_UNSUCCESSFUL;
689 }
690
691 /* only interested in A records as a shortcut for having to come
692 back later and lookup the name */
693
694 if (rr.type != T_A || rr.rdatalen != 4) {
695#if defined(HAVE_IPV6)
696 if (rr.type != T_AAAA || rr.rdatalen != 16)
697#endif
698 continue;
699 }
700
701 for ( i=0; i<idx; i++ ) {
702 if (strcmp(rr.hostname, nsarray[i].hostname) == 0) {
703 if (rr.type == T_A) {
704 struct in_addr ip;
705 memcpy(&ip, rr.rdata, 4);
706 in_addr_to_sockaddr_storage(
707 &nsarray[i].ss,
708 ip);
709 }
710#if defined(HAVE_IPV6)
711 if (rr.type == T_AAAA) {
712 struct in6_addr ip6;
713 memcpy(&ip6, rr.rdata, rr.rdatalen);
714 in6_addr_to_sockaddr_storage(
715 &nsarray[i].ss,
716 ip6);
717 }
718#endif
719 }
720 }
721 }
722
723 *nslist = nsarray;
724 *numns = idx;
725
726 return NT_STATUS_OK;
727}
728
729/****************************************************************************
730 Store and fetch the AD client sitename.
731****************************************************************************/
732
733#define SITENAME_KEY "AD_SITENAME/DOMAIN/%s"
734
735static char *sitename_key(const char *realm)
736{
737 char *keystr;
738
739 if (asprintf_strupper_m(&keystr, SITENAME_KEY, realm) == -1) {
740 return NULL;
741 }
742
743 return keystr;
744}
745
746
747/****************************************************************************
748 Store the AD client sitename.
749 We store indefinately as every new CLDAP query will re-write this.
750****************************************************************************/
751
752bool sitename_store(const char *realm, const char *sitename)
753{
754 time_t expire;
755 bool ret = False;
756 char *key;
757
758 if (!realm || (strlen(realm) == 0)) {
759 DEBUG(0,("sitename_store: no realm\n"));
760 return False;
761 }
762
763 key = sitename_key(realm);
764
765 if (!sitename || (sitename && !*sitename)) {
766 DEBUG(5,("sitename_store: deleting empty sitename!\n"));
767 ret = gencache_del(key);
768 SAFE_FREE(key);
769 return ret;
770 }
771
772 expire = get_time_t_max(); /* Store indefinately. */
773
774 DEBUG(10,("sitename_store: realm = [%s], sitename = [%s], expire = [%u]\n",
775 realm, sitename, (unsigned int)expire ));
776
777 ret = gencache_set( key, sitename, expire );
778 SAFE_FREE(key);
779 return ret;
780}
781
782/****************************************************************************
783 Fetch the AD client sitename.
784 Caller must free.
785****************************************************************************/
786
787char *sitename_fetch(const char *realm)
788{
789 char *sitename = NULL;
790 time_t timeout;
791 bool ret = False;
792 const char *query_realm;
793 char *key;
794
795 if (!realm || (strlen(realm) == 0)) {
796 query_realm = lp_realm();
797 } else {
798 query_realm = realm;
799 }
800
801 key = sitename_key(query_realm);
802
803 ret = gencache_get( key, &sitename, &timeout );
804 SAFE_FREE(key);
805 if ( !ret ) {
806 DEBUG(5,("sitename_fetch: No stored sitename for %s\n",
807 query_realm));
808 } else {
809 DEBUG(5,("sitename_fetch: Returning sitename for %s: \"%s\"\n",
810 query_realm, sitename ));
811 }
812 return sitename;
813}
814
815/****************************************************************************
816 Did the sitename change ?
817****************************************************************************/
818
819bool stored_sitename_changed(const char *realm, const char *sitename)
820{
821 bool ret = False;
822
823 char *new_sitename;
824
825 if (!realm || (strlen(realm) == 0)) {
826 DEBUG(0,("stored_sitename_changed: no realm\n"));
827 return False;
828 }
829
830 new_sitename = sitename_fetch(realm);
831
832 if (sitename && new_sitename && !strequal(sitename, new_sitename)) {
833 ret = True;
834 } else if ((sitename && !new_sitename) ||
835 (!sitename && new_sitename)) {
836 ret = True;
837 }
838 SAFE_FREE(new_sitename);
839 return ret;
840}
841
842/********************************************************************
843 Query with optional sitename.
844********************************************************************/
845
846static NTSTATUS ads_dns_query_internal(TALLOC_CTX *ctx,
847 const char *servicename,
848 const char *dc_pdc_gc_domains,
849 const char *realm,
850 const char *sitename,
851 struct dns_rr_srv **dclist,
852 int *numdcs )
853{
854 char *name;
855 if (sitename) {
856 name = talloc_asprintf(ctx, "%s._tcp.%s._sites.%s._msdcs.%s",
857 servicename, sitename,
858 dc_pdc_gc_domains, realm);
859 } else {
860 name = talloc_asprintf(ctx, "%s._tcp.%s._msdcs.%s",
861 servicename, dc_pdc_gc_domains, realm);
862 }
863 if (!name) {
864 return NT_STATUS_NO_MEMORY;
865 }
866 return ads_dns_lookup_srv( ctx, name, dclist, numdcs );
867}
868
869/********************************************************************
870 Query for AD DC's.
871********************************************************************/
872
873NTSTATUS ads_dns_query_dcs(TALLOC_CTX *ctx,
874 const char *realm,
875 const char *sitename,
876 struct dns_rr_srv **dclist,
877 int *numdcs )
878{
879 NTSTATUS status;
880
881 status = ads_dns_query_internal(ctx, "_ldap", "dc", realm, sitename,
882 dclist, numdcs);
883
884 if (NT_STATUS_EQUAL(status, NT_STATUS_IO_TIMEOUT) ||
885 NT_STATUS_EQUAL(status, NT_STATUS_CONNECTION_REFUSED)) {
886 return status;
887 }
888
889 if (sitename &&
890 ((!NT_STATUS_IS_OK(status)) ||
891 (NT_STATUS_IS_OK(status) && (numdcs == 0)))) {
892 /* Sitename DNS query may have failed. Try without. */
893 status = ads_dns_query_internal(ctx, "_ldap", "dc", realm,
894 NULL, dclist, numdcs);
895 }
896 return status;
897}
898
899/********************************************************************
900 Query for AD GC's.
901********************************************************************/
902
903NTSTATUS ads_dns_query_gcs(TALLOC_CTX *ctx,
904 const char *realm,
905 const char *sitename,
906 struct dns_rr_srv **dclist,
907 int *numdcs )
908{
909 NTSTATUS status;
910
911 status = ads_dns_query_internal(ctx, "_ldap", "gc", realm, sitename,
912 dclist, numdcs);
913
914 if (NT_STATUS_EQUAL(status, NT_STATUS_IO_TIMEOUT) ||
915 NT_STATUS_EQUAL(status, NT_STATUS_CONNECTION_REFUSED)) {
916 return status;
917 }
918
919 if (sitename &&
920 ((!NT_STATUS_IS_OK(status)) ||
921 (NT_STATUS_IS_OK(status) && (numdcs == 0)))) {
922 /* Sitename DNS query may have failed. Try without. */
923 status = ads_dns_query_internal(ctx, "_ldap", "gc", realm,
924 NULL, dclist, numdcs);
925 }
926 return status;
927}
928
929/********************************************************************
930 Query for AD KDC's.
931 Even if our underlying kerberos libraries are UDP only, this
932 is pretty safe as it's unlikely that a KDC supports TCP and not UDP.
933********************************************************************/
934
935NTSTATUS ads_dns_query_kdcs(TALLOC_CTX *ctx,
936 const char *dns_forest_name,
937 const char *sitename,
938 struct dns_rr_srv **dclist,
939 int *numdcs )
940{
941 NTSTATUS status;
942
943 status = ads_dns_query_internal(ctx, "_kerberos", "dc",
944 dns_forest_name, sitename, dclist,
945 numdcs);
946
947 if (NT_STATUS_EQUAL(status, NT_STATUS_IO_TIMEOUT) ||
948 NT_STATUS_EQUAL(status, NT_STATUS_CONNECTION_REFUSED)) {
949 return status;
950 }
951
952 if (sitename &&
953 ((!NT_STATUS_IS_OK(status)) ||
954 (NT_STATUS_IS_OK(status) && (numdcs == 0)))) {
955 /* Sitename DNS query may have failed. Try without. */
956 status = ads_dns_query_internal(ctx, "_kerberos", "dc",
957 dns_forest_name, NULL,
958 dclist, numdcs);
959 }
960 return status;
961}
962
963/********************************************************************
964 Query for AD PDC. Sitename is obsolete here.
965********************************************************************/
966
967NTSTATUS ads_dns_query_pdc(TALLOC_CTX *ctx,
968 const char *dns_domain_name,
969 struct dns_rr_srv **dclist,
970 int *numdcs )
971{
972 return ads_dns_query_internal(ctx, "_ldap", "pdc", dns_domain_name,
973 NULL, dclist, numdcs);
974}
975
976/********************************************************************
977 Query for AD DC by guid. Sitename is obsolete here.
978********************************************************************/
979
980NTSTATUS ads_dns_query_dcs_guid(TALLOC_CTX *ctx,
981 const char *dns_forest_name,
982 const struct GUID *domain_guid,
983 struct dns_rr_srv **dclist,
984 int *numdcs )
985{
986 /*_ldap._tcp.DomainGuid.domains._msdcs.DnsForestName */
987
988 const char *domains;
989 char *guid_string;
990
991 guid_string = GUID_string(ctx, domain_guid);
992 if (!guid_string) {
993 return NT_STATUS_NO_MEMORY;
994 }
995
996 /* little hack */
997 domains = talloc_asprintf(ctx, "%s.domains", guid_string);
998 if (!domains) {
999 return NT_STATUS_NO_MEMORY;
1000 }
1001 TALLOC_FREE(guid_string);
1002
1003 return ads_dns_query_internal(ctx, "_ldap", domains, dns_forest_name,
1004 NULL, dclist, numdcs);
1005}
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