2 Unix SMB/CIFS implementation.
4 Copyright (C) Gerald (Jerry) Carter 2006.
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
23 /* AIX resolv.h uses 'class' in struct ns_rr */
31 /* resolver headers */
33 #include <sys/types.h>
34 #include <netinet/in.h>
35 #include <arpa/nameser.h>
39 #define MAX_DNS_PACKET_SIZE 0xffff
41 #ifdef NS_HFIXEDSZ /* Bind 8/9 interface */
42 #if !defined(C_IN) /* AIX 5.3 already defines C_IN */
45 #if !defined(T_A) /* AIX 5.3 already defines T_A */
48 # define T_SRV ns_t_srv
49 #if !defined(T_NS) /* AIX 5.3 already defines T_NS */
54 # define NS_HFIXEDSZ HFIXEDSZ
56 # define NS_HFIXEDSZ sizeof(HEADER)
57 # endif /* HFIXEDSZ */
59 # define NS_PACKETSZ PACKETSZ
60 # else /* 512 is usually the default */
61 # define NS_PACKETSZ 512
62 # endif /* PACKETSZ */
66 /*********************************************************************
67 *********************************************************************/
69 static BOOL ads_dns_parse_query( TALLOC_CTX *ctx, uint8 *start, uint8 *end,
70 uint8 **ptr, struct dns_query *q )
78 if ( !start || !end || !q || !*ptr)
81 /* See RFC 1035 for details. If this fails, then return. */
83 namelen = dn_expand( start, end, p, hostname, sizeof(hostname) );
88 q->hostname = talloc_strdup( ctx, hostname );
90 /* check that we have space remaining */
92 if ( PTR_DIFF(p+4, end) > 0 )
95 q->type = RSVAL( p, 0 );
96 q->in_class = RSVAL( p, 2 );
104 /*********************************************************************
105 *********************************************************************/
107 static BOOL ads_dns_parse_rr( TALLOC_CTX *ctx, uint8 *start, uint8 *end,
108 uint8 **ptr, struct dns_rr *rr )
114 if ( !start || !end || !rr || !*ptr)
118 /* pull the name from the answer */
120 namelen = dn_expand( start, end, p, hostname, sizeof(hostname) );
125 rr->hostname = talloc_strdup( ctx, hostname );
127 /* check that we have space remaining */
129 if ( PTR_DIFF(p+10, end) > 0 )
132 /* pull some values and then skip onto the string */
134 rr->type = RSVAL(p, 0);
135 rr->in_class = RSVAL(p, 2);
136 rr->ttl = RIVAL(p, 4);
137 rr->rdatalen = RSVAL(p, 8);
141 /* sanity check the available space */
143 if ( PTR_DIFF(p+rr->rdatalen, end ) > 0 ) {
148 /* save a point to the rdata for this section */
158 /*********************************************************************
159 *********************************************************************/
161 static BOOL ads_dns_parse_rr_srv( TALLOC_CTX *ctx, uint8 *start, uint8 *end,
162 uint8 **ptr, struct dns_rr_srv *srv )
169 if ( !start || !end || !srv || !*ptr)
172 /* Parse the RR entry. Coming out of the this, ptr is at the beginning
173 of the next record */
175 if ( !ads_dns_parse_rr( ctx, start, end, ptr, &rr ) ) {
176 DEBUG(1,("ads_dns_parse_rr_srv: Failed to parse RR record\n"));
180 if ( rr.type != T_SRV ) {
181 DEBUG(1,("ads_dns_parse_rr_srv: Bad answer type (%d)\n", rr.type));
187 srv->priority = RSVAL(p, 0);
188 srv->weight = RSVAL(p, 2);
189 srv->port = RSVAL(p, 4);
193 namelen = dn_expand( start, end, p, dcname, sizeof(dcname) );
195 DEBUG(1,("ads_dns_parse_rr_srv: Failed to uncompress name!\n"));
198 srv->hostname = talloc_strdup( ctx, dcname );
203 /*********************************************************************
204 *********************************************************************/
206 static BOOL ads_dns_parse_rr_ns( TALLOC_CTX *ctx, uint8 *start, uint8 *end,
207 uint8 **ptr, struct dns_rr_ns *nsrec )
214 if ( !start || !end || !nsrec || !*ptr)
217 /* Parse the RR entry. Coming out of the this, ptr is at the beginning
218 of the next record */
220 if ( !ads_dns_parse_rr( ctx, start, end, ptr, &rr ) ) {
221 DEBUG(1,("ads_dns_parse_rr_ns: Failed to parse RR record\n"));
225 if ( rr.type != T_NS ) {
226 DEBUG(1,("ads_dns_parse_rr_ns: Bad answer type (%d)\n", rr.type));
232 /* ame server hostname */
234 namelen = dn_expand( start, end, p, nsname, sizeof(nsname) );
236 DEBUG(1,("ads_dns_parse_rr_ns: Failed to uncompress name!\n"));
239 nsrec->hostname = talloc_strdup( ctx, nsname );
244 /*********************************************************************
245 Sort SRV record list based on weight and priority. See RFC 2782.
246 *********************************************************************/
248 static int dnssrvcmp( struct dns_rr_srv *a, struct dns_rr_srv *b )
250 if ( a->priority == b->priority ) {
252 /* randomize entries with an equal weight and priority */
253 if ( a->weight == b->weight )
256 /* higher weights should be sorted lower */
257 if ( a->weight > b->weight )
263 if ( a->priority < b->priority )
269 /*********************************************************************
270 Simple wrapper for a DNS query
271 *********************************************************************/
273 #define DNS_FAILED_WAITTIME 30
275 static NTSTATUS dns_send_req( TALLOC_CTX *ctx, const char *name, int q_type,
276 uint8 **buf, int *resp_length )
278 uint8 *buffer = NULL;
280 int resp_len = NS_PACKETSZ;
281 static time_t last_dns_check = 0;
282 static NTSTATUS last_dns_status = NT_STATUS_OK;
283 time_t now = time(NULL);
285 /* Try to prevent bursts of DNS lookups if the server is down */
287 /* Protect against large clock changes */
289 if ( last_dns_check > now )
292 /* IF we had a DNS timeout or a bad server and we are still
293 in the 30 second cache window, just return the previous
294 status and save the network timeout. */
296 if ( (NT_STATUS_EQUAL(last_dns_status,NT_STATUS_IO_TIMEOUT) ||
297 NT_STATUS_EQUAL(last_dns_status,NT_STATUS_CONNECTION_REFUSED)) &&
298 (last_dns_check+DNS_FAILED_WAITTIME) > now )
300 DEBUG(10,("last_dns_check: Returning cached status (%s)\n",
301 nt_errstr(last_dns_status) ));
302 return last_dns_status;
308 TALLOC_FREE( buffer );
310 buf_len = resp_len * sizeof(uint8);
313 if ( (buffer = TALLOC_ARRAY(ctx, uint8, buf_len)) == NULL ) {
314 DEBUG(0,("ads_dns_lookup_srv: talloc() failed!\n"));
315 last_dns_status = NT_STATUS_NO_MEMORY;
316 last_dns_check = time(NULL);
317 return last_dns_status;
321 if ( (resp_len = res_query(name, C_IN, q_type, buffer, buf_len)) < 0 ) {
322 DEBUG(3,("ads_dns_lookup_srv: Failed to resolve %s (%s)\n", name, strerror(errno)));
323 TALLOC_FREE( buffer );
324 last_dns_status = NT_STATUS_UNSUCCESSFUL;
326 if (errno == ETIMEDOUT) {
327 last_dns_status = NT_STATUS_IO_TIMEOUT;
329 if (errno == ECONNREFUSED) {
330 last_dns_status = NT_STATUS_CONNECTION_REFUSED;
332 last_dns_check = time(NULL);
333 return last_dns_status;
335 } while ( buf_len < resp_len && resp_len < MAX_DNS_PACKET_SIZE );
338 *resp_length = resp_len;
340 last_dns_check = time(NULL);
341 last_dns_status = NT_STATUS_OK;
342 return last_dns_status;
345 /*********************************************************************
346 Simple wrapper for a DNS SRV query
347 *********************************************************************/
349 static NTSTATUS ads_dns_lookup_srv( TALLOC_CTX *ctx, const char *name, struct dns_rr_srv **dclist, int *numdcs )
351 uint8 *buffer = NULL;
353 struct dns_rr_srv *dcs = NULL;
354 int query_count, answer_count, auth_count, additional_count;
360 if ( !ctx || !name || !dclist ) {
361 return NT_STATUS_INVALID_PARAMETER;
364 /* Send the request. May have to loop several times in case
367 status = dns_send_req( ctx, name, T_SRV, &buffer, &resp_len );
368 if ( !NT_STATUS_IS_OK(status) ) {
369 DEBUG(3,("ads_dns_lookup_srv: Failed to send DNS query (%s)\n",
375 /* For some insane reason, the ns_initparse() et. al. routines are only
376 available in libresolv.a, and not the shared lib. Who knows why....
377 So we have to parse the DNS reply ourselves */
379 /* Pull the answer RR's count from the header. Use the NMB ordering macros */
381 query_count = RSVAL( p, 4 );
382 answer_count = RSVAL( p, 6 );
383 auth_count = RSVAL( p, 8 );
384 additional_count = RSVAL( p, 10 );
386 DEBUG(4,("ads_dns_lookup_srv: %d records returned in the answer section.\n",
390 if ( (dcs = TALLOC_ZERO_ARRAY(ctx, struct dns_rr_srv, answer_count)) == NULL ) {
391 DEBUG(0,("ads_dns_lookup_srv: talloc() failure for %d char*'s\n",
393 return NT_STATUS_NO_MEMORY;
399 /* now skip the header */
403 /* parse the query section */
405 for ( rrnum=0; rrnum<query_count; rrnum++ ) {
408 if ( !ads_dns_parse_query( ctx, buffer, buffer+resp_len, &p, &q ) ) {
409 DEBUG(1,("ads_dns_lookup_srv: Failed to parse query record!\n"));
410 return NT_STATUS_UNSUCCESSFUL;
414 /* now we are at the answer section */
416 for ( rrnum=0; rrnum<answer_count; rrnum++ ) {
417 if ( !ads_dns_parse_rr_srv( ctx, buffer, buffer+resp_len, &p, &dcs[rrnum] ) ) {
418 DEBUG(1,("ads_dns_lookup_srv: Failed to parse answer record!\n"));
419 return NT_STATUS_UNSUCCESSFUL;
424 /* Parse the authority section */
425 /* just skip these for now */
427 for ( rrnum=0; rrnum<auth_count; rrnum++ ) {
430 if ( !ads_dns_parse_rr( ctx, buffer, buffer+resp_len, &p, &rr ) ) {
431 DEBUG(1,("ads_dns_lookup_srv: Failed to parse authority record!\n"));
432 return NT_STATUS_UNSUCCESSFUL;
436 /* Parse the additional records section */
438 for ( rrnum=0; rrnum<additional_count; rrnum++ ) {
442 if ( !ads_dns_parse_rr( ctx, buffer, buffer+resp_len, &p, &rr ) ) {
443 DEBUG(1,("ads_dns_lookup_srv: Failed to parse additional records section!\n"));
444 return NT_STATUS_UNSUCCESSFUL;
447 /* only interested in A records as a shortcut for having to come
448 back later and lookup the name. For multi-homed hosts, the
449 number of additional records and exceed the number of answer
453 if ( (rr.type != T_A) || (rr.rdatalen != 4) )
456 for ( i=0; i<idx; i++ ) {
457 if ( strcmp( rr.hostname, dcs[i].hostname ) == 0 ) {
458 int num_ips = dcs[i].num_ips;
460 struct in_addr *tmp_ips;
462 /* allocate new memory */
464 if ( dcs[i].num_ips == 0 ) {
465 if ( (dcs[i].ips = TALLOC_ARRAY( dcs,
466 struct in_addr, 1 )) == NULL )
468 return NT_STATUS_NO_MEMORY;
471 if ( (tmp_ips = TALLOC_REALLOC_ARRAY( dcs, dcs[i].ips,
472 struct in_addr, dcs[i].num_ips+1)) == NULL )
474 return NT_STATUS_NO_MEMORY;
477 dcs[i].ips = tmp_ips;
481 /* copy the new IP address */
483 buf = (uint8*)&dcs[i].ips[num_ips].s_addr;
484 memcpy( buf, rr.rdata, 4 );
489 qsort( dcs, idx, sizeof(struct dns_rr_srv), QSORT_CAST dnssrvcmp );
497 /*********************************************************************
498 Simple wrapper for a DNS NS query
499 *********************************************************************/
501 NTSTATUS ads_dns_lookup_ns( TALLOC_CTX *ctx, const char *dnsdomain, struct dns_rr_ns **nslist, int *numns )
503 uint8 *buffer = NULL;
505 struct dns_rr_ns *nsarray = NULL;
506 int query_count, answer_count, auth_count, additional_count;
512 if ( !ctx || !dnsdomain || !nslist ) {
513 return NT_STATUS_INVALID_PARAMETER;
516 /* Send the request. May have to loop several times in case
519 status = dns_send_req( ctx, dnsdomain, T_NS, &buffer, &resp_len );
520 if ( !NT_STATUS_IS_OK(status) ) {
521 DEBUG(3,("ads_dns_lookup_ns: Failed to send DNS query (%s)\n",
527 /* For some insane reason, the ns_initparse() et. al. routines are only
528 available in libresolv.a, and not the shared lib. Who knows why....
529 So we have to parse the DNS reply ourselves */
531 /* Pull the answer RR's count from the header. Use the NMB ordering macros */
533 query_count = RSVAL( p, 4 );
534 answer_count = RSVAL( p, 6 );
535 auth_count = RSVAL( p, 8 );
536 additional_count = RSVAL( p, 10 );
538 DEBUG(4,("ads_dns_lookup_ns: %d records returned in the answer section.\n",
542 if ( (nsarray = TALLOC_ARRAY(ctx, struct dns_rr_ns, answer_count)) == NULL ) {
543 DEBUG(0,("ads_dns_lookup_ns: talloc() failure for %d char*'s\n",
545 return NT_STATUS_NO_MEMORY;
551 /* now skip the header */
555 /* parse the query section */
557 for ( rrnum=0; rrnum<query_count; rrnum++ ) {
560 if ( !ads_dns_parse_query( ctx, buffer, buffer+resp_len, &p, &q ) ) {
561 DEBUG(1,("ads_dns_lookup_ns: Failed to parse query record!\n"));
562 return NT_STATUS_UNSUCCESSFUL;
566 /* now we are at the answer section */
568 for ( rrnum=0; rrnum<answer_count; rrnum++ ) {
569 if ( !ads_dns_parse_rr_ns( ctx, buffer, buffer+resp_len, &p, &nsarray[rrnum] ) ) {
570 DEBUG(1,("ads_dns_lookup_ns: Failed to parse answer record!\n"));
571 return NT_STATUS_UNSUCCESSFUL;
576 /* Parse the authority section */
577 /* just skip these for now */
579 for ( rrnum=0; rrnum<auth_count; rrnum++ ) {
582 if ( !ads_dns_parse_rr( ctx, buffer, buffer+resp_len, &p, &rr ) ) {
583 DEBUG(1,("ads_dns_lookup_ns: Failed to parse authority record!\n"));
584 return NT_STATUS_UNSUCCESSFUL;
588 /* Parse the additional records section */
590 for ( rrnum=0; rrnum<additional_count; rrnum++ ) {
594 if ( !ads_dns_parse_rr( ctx, buffer, buffer+resp_len, &p, &rr ) ) {
595 DEBUG(1,("ads_dns_lookup_ns: Failed to parse additional records section!\n"));
596 return NT_STATUS_UNSUCCESSFUL;
599 /* only interested in A records as a shortcut for having to come
600 back later and lookup the name */
602 if ( (rr.type != T_A) || (rr.rdatalen != 4) )
605 for ( i=0; i<idx; i++ ) {
606 if ( strcmp( rr.hostname, nsarray[i].hostname ) == 0 ) {
607 uint8 *buf = (uint8*)&nsarray[i].ip.s_addr;
608 memcpy( buf, rr.rdata, 4 );
619 /****************************************************************************
620 Store and fetch the AD client sitename.
621 ****************************************************************************/
623 #define SITENAME_KEY "AD_SITENAME/DOMAIN/%s"
625 static char *sitename_key(const char *realm)
629 if (asprintf(&keystr, SITENAME_KEY, strupper_static(realm)) == -1) {
637 /****************************************************************************
638 Store the AD client sitename.
639 We store indefinately as every new CLDAP query will re-write this.
640 If the sitename is "Default-First-Site-Name" we don't store it
641 as this isn't a valid DNS name.
642 ****************************************************************************/
644 BOOL sitename_store(const char *realm, const char *sitename)
650 if (!gencache_init()) {
654 if (!realm || (strlen(realm) == 0)) {
655 DEBUG(0,("no realm\n"));
659 key = sitename_key(realm);
661 if (!sitename || (sitename && !*sitename)) {
662 DEBUG(5,("sitename_store: deleting empty sitename!\n"));
663 ret = gencache_del(key);
668 expire = get_time_t_max(); /* Store indefinately. */
670 DEBUG(10,("sitename_store: realm = [%s], sitename = [%s], expire = [%u]\n",
671 realm, sitename, (unsigned int)expire ));
673 ret = gencache_set( key, sitename, expire );
678 /****************************************************************************
679 Fetch the AD client sitename.
681 ****************************************************************************/
683 char *sitename_fetch(const char *realm)
685 char *sitename = NULL;
688 const char *query_realm;
691 if (!gencache_init()) {
695 if (!realm || (strlen(realm) == 0)) {
696 query_realm = lp_realm();
701 key = sitename_key(query_realm);
703 ret = gencache_get( key, &sitename, &timeout );
706 DEBUG(5,("sitename_fetch: No stored sitename for %s\n",
709 DEBUG(5,("sitename_fetch: Returning sitename for %s: \"%s\"\n",
710 query_realm, sitename ));
715 /****************************************************************************
716 Did the sitename change ?
717 ****************************************************************************/
719 BOOL stored_sitename_changed(const char *realm, const char *sitename)
725 if (!realm || (strlen(realm) == 0)) {
726 DEBUG(0,("no realm\n"));
730 new_sitename = sitename_fetch(realm);
732 if (sitename && new_sitename && !strequal(sitename, new_sitename)) {
734 } else if ((sitename && !new_sitename) ||
735 (!sitename && new_sitename)) {
738 SAFE_FREE(new_sitename);
742 /********************************************************************
743 Query with optional sitename.
744 ********************************************************************/
746 NTSTATUS ads_dns_query_internal(TALLOC_CTX *ctx,
747 const char *servicename,
749 const char *sitename,
750 struct dns_rr_srv **dclist,
755 name = talloc_asprintf(ctx, "%s._tcp.%s._sites.dc._msdcs.%s",
756 servicename, sitename, realm );
758 name = talloc_asprintf(ctx, "%s._tcp.dc._msdcs.%s",
759 servicename, realm );
762 return NT_STATUS_NO_MEMORY;
764 return ads_dns_lookup_srv( ctx, name, dclist, numdcs );
767 /********************************************************************
769 ********************************************************************/
771 NTSTATUS ads_dns_query_dcs(TALLOC_CTX *ctx,
773 const char *sitename,
774 struct dns_rr_srv **dclist,
779 status = ads_dns_query_internal(ctx, "_ldap", realm, sitename,
782 if (NT_STATUS_EQUAL(status, NT_STATUS_IO_TIMEOUT) ||
783 NT_STATUS_EQUAL(status, NT_STATUS_CONNECTION_REFUSED)) {
787 if (sitename && !NT_STATUS_IS_OK(status)) {
788 /* Sitename DNS query may have failed. Try without. */
789 status = ads_dns_query_internal(ctx, "_ldap", realm, NULL,
795 /********************************************************************
797 Even if our underlying kerberos libraries are UDP only, this
798 is pretty safe as it's unlikely that a KDC supports TCP and not UDP.
799 ********************************************************************/
801 NTSTATUS ads_dns_query_kdcs(TALLOC_CTX *ctx,
803 const char *sitename,
804 struct dns_rr_srv **dclist,
809 status = ads_dns_query_internal(ctx, "_kerberos", realm, sitename,
812 if (NT_STATUS_EQUAL(status, NT_STATUS_IO_TIMEOUT) ||
813 NT_STATUS_EQUAL(status, NT_STATUS_CONNECTION_REFUSED)) {
817 if (sitename && !NT_STATUS_IS_OK(status)) {
818 /* Sitename DNS query may have failed. Try without. */
819 status = ads_dns_query_internal(ctx, "_kerberos", realm, NULL,