lib: Fix CID 1273234 Untrusted value as argument
[sfrench/samba-autobuild/.git] / lib / addns / dnsquery.c
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
79 static 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
117 static 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
171 static 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
224 static 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
267 static 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
294 static 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
392 NTSTATUS 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
581 NTSTATUS 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
736 static 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
763 NTSTATUS 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
803 NTSTATUS 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
845 NTSTATUS 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
885 NTSTATUS 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
903 NTSTATUS 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 }