addns: Make ads_dns_lookup_srv pulic
[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,("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,("ads_dns_lookup_srv: "
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,("ads_dns_lookup_srv: "
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 *dns_hosts_file,
394                                 const char *name,
395                                 struct dns_rr_srv **dclist,
396                                 int *numdcs)
397 {
398         uint8_t *buffer = NULL;
399         int resp_len = 0;
400         struct dns_rr_srv *dcs = NULL;
401         int query_count, answer_count, auth_count, additional_count;
402         uint8_t *p = buffer;
403         int rrnum;
404         int idx = 0;
405         NTSTATUS status;
406
407         if ( !ctx || !name || !dclist ) {
408                 return NT_STATUS_INVALID_PARAMETER;
409         }
410
411         if (dns_hosts_file) {
412                 return resolve_dns_hosts_file_as_dns_rr(dns_hosts_file,
413                                                         name, true, ctx,
414                                                         dclist, numdcs);
415         }
416
417         /* Send the request.  May have to loop several times in case
418            of large replies */
419
420         status = dns_send_req( ctx, name, T_SRV, &buffer, &resp_len );
421         if ( !NT_STATUS_IS_OK(status) ) {
422                 DEBUG(3,("ads_dns_lookup_srv: Failed to send DNS query (%s)\n",
423                         nt_errstr(status)));
424                 return status;
425         }
426         p = buffer;
427
428         /* For some insane reason, the ns_initparse() et. al. routines are only
429            available in libresolv.a, and not the shared lib.  Who knows why....
430            So we have to parse the DNS reply ourselves */
431
432         /* Pull the answer RR's count from the header.
433          * Use the NMB ordering macros */
434
435         query_count      = RSVAL( p, 4 );
436         answer_count     = RSVAL( p, 6 );
437         auth_count       = RSVAL( p, 8 );
438         additional_count = RSVAL( p, 10 );
439
440         DEBUG(4,("ads_dns_lookup_srv: "
441                 "%d records returned in the answer section.\n",
442                 answer_count));
443
444         if (answer_count) {
445                 if ((dcs = talloc_zero_array(ctx, struct dns_rr_srv,
446                                                 answer_count)) == NULL ) {
447                         DEBUG(0,("ads_dns_lookup_srv: "
448                                 "talloc() failure for %d char*'s\n",
449                                 answer_count));
450                         return NT_STATUS_NO_MEMORY;
451                 }
452         } else {
453                 dcs = NULL;
454         }
455
456         /* now skip the header */
457
458         p += NS_HFIXEDSZ;
459
460         /* parse the query section */
461
462         for ( rrnum=0; rrnum<query_count; rrnum++ ) {
463                 struct dns_query q;
464
465                 if (!ads_dns_parse_query(ctx, buffer,
466                                         buffer+resp_len, &p, &q)) {
467                         DEBUG(1,("ads_dns_lookup_srv: "
468                                  "Failed to parse query record [%d]!\n", rrnum));
469                         return NT_STATUS_UNSUCCESSFUL;
470                 }
471         }
472
473         /* now we are at the answer section */
474
475         for ( rrnum=0; rrnum<answer_count; rrnum++ ) {
476                 if (!ads_dns_parse_rr_srv(ctx, buffer, buffer+resp_len,
477                                         &p, &dcs[rrnum])) {
478                         DEBUG(1,("ads_dns_lookup_srv: "
479                                  "Failed to parse answer recordi [%d]!\n", rrnum));
480                         return NT_STATUS_UNSUCCESSFUL;
481                 }
482         }
483         idx = rrnum;
484
485         /* Parse the authority section */
486         /* just skip these for now */
487
488         for ( rrnum=0; rrnum<auth_count; rrnum++ ) {
489                 struct dns_rr rr;
490
491                 if (!ads_dns_parse_rr( ctx, buffer,
492                                         buffer+resp_len, &p, &rr)) {
493                         DEBUG(1,("ads_dns_lookup_srv: "
494                                  "Failed to parse authority record! [%d]\n", rrnum));
495                         return NT_STATUS_UNSUCCESSFUL;
496                 }
497         }
498
499         /* Parse the additional records section */
500
501         for ( rrnum=0; rrnum<additional_count; rrnum++ ) {
502                 struct dns_rr rr;
503                 int i;
504
505                 if (!ads_dns_parse_rr(ctx, buffer, buffer+resp_len,
506                                         &p, &rr)) {
507                         DEBUG(1,("ads_dns_lookup_srv: Failed "
508                                  "to parse additional records section! [%d]\n", rrnum));
509                         return NT_STATUS_UNSUCCESSFUL;
510                 }
511
512                 /* Only interested in A or AAAA records as a shortcut for having
513                  * to come back later and lookup the name. For multi-homed
514                  * hosts, the number of additional records and exceed the
515                  * number of answer records. */
516
517                 if (rr.type != T_A || rr.rdatalen != 4) {
518 #if defined(HAVE_IPV6)
519                         /* RFC2874 defines A6 records. This
520                          * requires recusive and horribly complex lookups.
521                          * Bastards. Ignore this for now.... JRA.
522                          * Luckily RFC3363 reprecates A6 records.
523                          */
524                         if (rr.type != T_AAAA || rr.rdatalen != 16)
525 #endif
526                                 continue;
527                 }
528
529                 for ( i=0; i<idx; i++ ) {
530                         if ( strcmp( rr.hostname, dcs[i].hostname ) == 0 ) {
531                                 int num_ips = dcs[i].num_ips;
532                                 struct sockaddr_storage *tmp_ss_s;
533
534                                 /* allocate new memory */
535
536                                 if (dcs[i].num_ips == 0) {
537                                         if ((dcs[i].ss_s = talloc_array(dcs,
538                                                 struct sockaddr_storage, 1 ))
539                                                         == NULL ) {
540                                                 return NT_STATUS_NO_MEMORY;
541                                         }
542                                 } else {
543                                         if ((tmp_ss_s = talloc_realloc(dcs,
544                                                         dcs[i].ss_s,
545                                                         struct sockaddr_storage,
546                                                         dcs[i].num_ips+1))
547                                                                 == NULL ) {
548                                                 return NT_STATUS_NO_MEMORY;
549                                         }
550
551                                         dcs[i].ss_s = tmp_ss_s;
552                                 }
553                                 dcs[i].num_ips++;
554
555                                 /* copy the new IP address */
556                                 if (rr.type == T_A) {
557                                         struct in_addr ip;
558                                         memcpy(&ip, rr.rdata, 4);
559                                         in_addr_to_sockaddr_storage(
560                                                         &dcs[i].ss_s[num_ips],
561                                                         ip);
562                                 }
563 #if defined(HAVE_IPV6)
564                                 if (rr.type == T_AAAA) {
565                                         struct in6_addr ip6;
566                                         memcpy(&ip6, rr.rdata, rr.rdatalen);
567                                         in6_addr_to_sockaddr_storage(
568                                                         &dcs[i].ss_s[num_ips],
569                                                         ip6);
570                                 }
571 #endif
572                         }
573                 }
574         }
575
576         TYPESAFE_QSORT(dcs, idx, dnssrvcmp );
577
578         *dclist = dcs;
579         *numdcs = idx;
580
581         return NT_STATUS_OK;
582 }
583
584 /*********************************************************************
585  Simple wrapper for a DNS NS query
586 *********************************************************************/
587
588 NTSTATUS ads_dns_lookup_ns(TALLOC_CTX *ctx,
589                                 const char *dns_hosts_file,
590                                 const char *dnsdomain,
591                                 struct dns_rr_ns **nslist,
592                                 int *numns)
593 {
594         uint8_t *buffer = NULL;
595         int resp_len = 0;
596         struct dns_rr_ns *nsarray = NULL;
597         int query_count, answer_count, auth_count, additional_count;
598         uint8_t *p;
599         int rrnum;
600         int idx = 0;
601         NTSTATUS status;
602
603         if ( !ctx || !dnsdomain || !nslist ) {
604                 return NT_STATUS_INVALID_PARAMETER;
605         }
606
607         if (dns_hosts_file) {
608                 DEBUG(1, ("NO 'NS' lookup available when using resolv:host file"));
609                 return NT_STATUS_OBJECT_NAME_NOT_FOUND;
610         }
611
612         /* Send the request.  May have to loop several times in case
613            of large replies */
614
615         status = dns_send_req( ctx, dnsdomain, T_NS, &buffer, &resp_len );
616         if ( !NT_STATUS_IS_OK(status) ) {
617                 DEBUG(3,("ads_dns_lookup_ns: Failed to send DNS query (%s)\n",
618                         nt_errstr(status)));
619                 return status;
620         }
621         p = buffer;
622
623         /* For some insane reason, the ns_initparse() et. al. routines are only
624            available in libresolv.a, and not the shared lib.  Who knows why....
625            So we have to parse the DNS reply ourselves */
626
627         /* Pull the answer RR's count from the header.
628          * Use the NMB ordering macros */
629
630         query_count      = RSVAL( p, 4 );
631         answer_count     = RSVAL( p, 6 );
632         auth_count       = RSVAL( p, 8 );
633         additional_count = RSVAL( p, 10 );
634
635         DEBUG(4,("ads_dns_lookup_ns: "
636                 "%d records returned in the answer section.\n",
637                 answer_count));
638
639         if (answer_count) {
640                 if ((nsarray = talloc_array(ctx, struct dns_rr_ns,
641                                                 answer_count)) == NULL ) {
642                         DEBUG(0,("ads_dns_lookup_ns: "
643                                 "talloc() failure for %d char*'s\n",
644                                 answer_count));
645                         return NT_STATUS_NO_MEMORY;
646                 }
647         } else {
648                 nsarray = NULL;
649         }
650
651         /* now skip the header */
652
653         p += NS_HFIXEDSZ;
654
655         /* parse the query section */
656
657         for ( rrnum=0; rrnum<query_count; rrnum++ ) {
658                 struct dns_query q;
659
660                 if (!ads_dns_parse_query(ctx, buffer, buffer+resp_len,
661                                         &p, &q)) {
662                         DEBUG(1,("ads_dns_lookup_ns: "
663                                 " Failed to parse query record!\n"));
664                         return NT_STATUS_UNSUCCESSFUL;
665                 }
666         }
667
668         /* now we are at the answer section */
669
670         for ( rrnum=0; rrnum<answer_count; rrnum++ ) {
671                 if (!ads_dns_parse_rr_ns(ctx, buffer, buffer+resp_len,
672                                         &p, &nsarray[rrnum])) {
673                         DEBUG(1,("ads_dns_lookup_ns: "
674                                 "Failed to parse answer record!\n"));
675                         return NT_STATUS_UNSUCCESSFUL;
676                 }
677         }
678         idx = rrnum;
679
680         /* Parse the authority section */
681         /* just skip these for now */
682
683         for ( rrnum=0; rrnum<auth_count; rrnum++ ) {
684                 struct dns_rr rr;
685
686                 if ( !ads_dns_parse_rr(ctx, buffer, buffer+resp_len,
687                                         &p, &rr)) {
688                         DEBUG(1,("ads_dns_lookup_ns: "
689                                 "Failed to parse authority record!\n"));
690                         return NT_STATUS_UNSUCCESSFUL;
691                 }
692         }
693
694         /* Parse the additional records section */
695
696         for ( rrnum=0; rrnum<additional_count; rrnum++ ) {
697                 struct dns_rr rr;
698                 int i;
699
700                 if (!ads_dns_parse_rr(ctx, buffer, buffer+resp_len,
701                                         &p, &rr)) {
702                         DEBUG(1,("ads_dns_lookup_ns: Failed "
703                                 "to parse additional records section!\n"));
704                         return NT_STATUS_UNSUCCESSFUL;
705                 }
706
707                 /* only interested in A records as a shortcut for having to come
708                    back later and lookup the name */
709
710                 if (rr.type != T_A || rr.rdatalen != 4) {
711 #if defined(HAVE_IPV6)
712                         if (rr.type != T_AAAA || rr.rdatalen != 16)
713 #endif
714                                 continue;
715                 }
716
717                 for ( i=0; i<idx; i++ ) {
718                         if (strcmp(rr.hostname, nsarray[i].hostname) == 0) {
719                                 if (rr.type == T_A) {
720                                         struct in_addr ip;
721                                         memcpy(&ip, rr.rdata, 4);
722                                         in_addr_to_sockaddr_storage(
723                                                         &nsarray[i].ss,
724                                                         ip);
725                                 }
726 #if defined(HAVE_IPV6)
727                                 if (rr.type == T_AAAA) {
728                                         struct in6_addr ip6;
729                                         memcpy(&ip6, rr.rdata, rr.rdatalen);
730                                         in6_addr_to_sockaddr_storage(
731                                                         &nsarray[i].ss,
732                                                         ip6);
733                                 }
734 #endif
735                         }
736                 }
737         }
738
739         *nslist = nsarray;
740         *numns = idx;
741
742         return NT_STATUS_OK;
743 }
744
745 /********************************************************************
746  Query with optional sitename.
747 ********************************************************************/
748
749 static NTSTATUS ads_dns_query_internal(TALLOC_CTX *ctx,
750                                        const char *dns_hosts_file,
751                                        const char *servicename,
752                                        const char *dc_pdc_gc_domains,
753                                        const char *realm,
754                                        const char *sitename,
755                                        struct dns_rr_srv **dclist,
756                                        int *numdcs )
757 {
758         char *name;
759         if (sitename && strlen(sitename)) {
760                 name = talloc_asprintf(ctx, "%s._tcp.%s._sites.%s._msdcs.%s",
761                                        servicename, sitename,
762                                        dc_pdc_gc_domains, realm);
763         } else {
764                 name = talloc_asprintf(ctx, "%s._tcp.%s._msdcs.%s",
765                                 servicename, dc_pdc_gc_domains, realm);
766         }
767         if (!name) {
768                 return NT_STATUS_NO_MEMORY;
769         }
770         return ads_dns_lookup_srv(ctx, dns_hosts_file, name, dclist, numdcs);
771 }
772
773 /********************************************************************
774  Query for AD DC's.
775 ********************************************************************/
776
777 NTSTATUS ads_dns_query_dcs(TALLOC_CTX *ctx,
778                            const char *dns_hosts_file,
779                            const char *realm,
780                            const char *sitename,
781                            struct dns_rr_srv **dclist,
782                            int *numdcs )
783 {
784         NTSTATUS status;
785
786         status = ads_dns_query_internal(ctx, dns_hosts_file, "_ldap", "dc",
787                                         realm, sitename, dclist, numdcs);
788
789         if (NT_STATUS_EQUAL(status, NT_STATUS_IO_TIMEOUT) ||
790             NT_STATUS_EQUAL(status, NT_STATUS_CONNECTION_REFUSED)) {
791                 return status;
792         }
793
794         if (sitename &&
795             ((!NT_STATUS_IS_OK(status)) ||
796              (NT_STATUS_IS_OK(status) && (numdcs == 0)))) {
797                 /* Sitename DNS query may have failed. Try without. */
798                 status = ads_dns_query_internal(ctx, dns_hosts_file,
799                                                 "_ldap", "dc", realm,
800                                                 NULL, dclist, numdcs);
801         }
802         return status;
803 }
804
805 /********************************************************************
806  Query for AD GC's.
807 ********************************************************************/
808
809 NTSTATUS ads_dns_query_gcs(TALLOC_CTX *ctx,
810                            const char *dns_hosts_file,
811                            const char *realm,
812                            const char *sitename,
813                            struct dns_rr_srv **dclist,
814                            int *numdcs )
815 {
816         NTSTATUS status;
817
818         status = ads_dns_query_internal(ctx, dns_hosts_file, "_ldap", "gc",
819                                         realm, sitename, dclist, numdcs);
820
821         if (NT_STATUS_EQUAL(status, NT_STATUS_IO_TIMEOUT) ||
822             NT_STATUS_EQUAL(status, NT_STATUS_CONNECTION_REFUSED)) {
823                 return status;
824         }
825
826         if (sitename &&
827             ((!NT_STATUS_IS_OK(status)) ||
828              (NT_STATUS_IS_OK(status) && (numdcs == 0)))) {
829                 /* Sitename DNS query may have failed. Try without. */
830                 status = ads_dns_query_internal(ctx, dns_hosts_file,
831                                                 "_ldap", "gc", realm,
832                                                 NULL, dclist, numdcs);
833         }
834         return status;
835 }
836
837 /********************************************************************
838  Query for AD KDC's.
839  Even if our underlying kerberos libraries are UDP only, this
840  is pretty safe as it's unlikely that a KDC supports TCP and not UDP.
841 ********************************************************************/
842
843 NTSTATUS ads_dns_query_kdcs(TALLOC_CTX *ctx,
844                             const char *dns_hosts_file,
845                             const char *dns_forest_name,
846                             const char *sitename,
847                             struct dns_rr_srv **dclist,
848                             int *numdcs )
849 {
850         NTSTATUS status;
851
852         status = ads_dns_query_internal(ctx, dns_hosts_file, "_kerberos", "dc",
853                                         dns_forest_name, sitename, dclist,
854                                         numdcs);
855
856         if (NT_STATUS_EQUAL(status, NT_STATUS_IO_TIMEOUT) ||
857             NT_STATUS_EQUAL(status, NT_STATUS_CONNECTION_REFUSED)) {
858                 return status;
859         }
860
861         if (sitename &&
862             ((!NT_STATUS_IS_OK(status)) ||
863              (NT_STATUS_IS_OK(status) && (numdcs == 0)))) {
864                 /* Sitename DNS query may have failed. Try without. */
865                 status = ads_dns_query_internal(ctx, dns_hosts_file,
866                                                 "_kerberos", "dc",
867                                                 dns_forest_name, NULL,
868                                                 dclist, numdcs);
869         }
870         return status;
871 }
872
873 /********************************************************************
874  Query for AD PDC. Sitename is obsolete here.
875 ********************************************************************/
876
877 NTSTATUS ads_dns_query_pdc(TALLOC_CTX *ctx,
878                            const char *dns_hosts_file,
879                            const char *dns_domain_name,
880                            struct dns_rr_srv **dclist,
881                            int *numdcs )
882 {
883         return ads_dns_query_internal(ctx, dns_hosts_file, "_ldap", "pdc",
884                                       dns_domain_name, NULL, dclist, numdcs);
885 }
886
887 /********************************************************************
888  Query for AD DC by guid. Sitename is obsolete here.
889 ********************************************************************/
890
891 NTSTATUS ads_dns_query_dcs_guid(TALLOC_CTX *ctx,
892                                 const char *dns_hosts_file,
893                                 const char *dns_forest_name,
894                                 const char *domain_guid,
895                                 struct dns_rr_srv **dclist,
896                                 int *numdcs )
897 {
898         /*_ldap._tcp.DomainGuid.domains._msdcs.DnsForestName */
899
900         const char *domains;
901
902         /* little hack */
903         domains = talloc_asprintf(ctx, "%s.domains", domain_guid);
904         if (!domains) {
905                 return NT_STATUS_NO_MEMORY;
906         }
907
908         return ads_dns_query_internal(ctx, dns_hosts_file, "_ldap", domains,
909                                       dns_forest_name, NULL, dclist, numdcs);
910 }