forked from NLnetLabs/nsd
-
Notifications
You must be signed in to change notification settings - Fork 0
/
query.c
1857 lines (1706 loc) · 53.4 KB
/
query.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/*
* query.c -- nsd(8) the resolver.
*
* Copyright (c) 2001-2006, NLnet Labs. All rights reserved.
*
* See LICENSE for the license.
*
*/
#include "config.h"
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <assert.h>
#include <ctype.h>
#include <errno.h>
#include <limits.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <netdb.h>
#include "answer.h"
#include "axfr.h"
#include "dns.h"
#include "dname.h"
#include "nsd.h"
#include "namedb.h"
#include "query.h"
#include "util.h"
#include "options.h"
#include "nsec3.h"
#include "tsig.h"
/* [Bug #253] Adding unnecessary NS RRset may lead to undesired truncation.
* This function determines if the final response packet needs the NS RRset
* included. Currently, it will only return negative if QTYPE == DNSKEY|DS.
* This way, resolvers won't fallback to TCP unnecessarily when priming
* trust anchors.
*/
static int answer_needs_ns(struct query *query);
static int add_rrset(struct query *query,
answer_type *answer,
rr_section_type section,
domain_type *owner,
rrset_type *rrset);
static void answer_authoritative(struct nsd *nsd,
struct query *q,
answer_type *answer,
size_t domain_number,
int exact,
domain_type *closest_match,
domain_type *closest_encloser,
const dname_type *qname);
static void answer_lookup_zone(struct nsd *nsd, struct query *q,
answer_type *answer, size_t domain_number,
int exact, domain_type *closest_match,
domain_type *closest_encloser,
const dname_type *qname);
void
query_put_dname_offset(struct query *q, domain_type *domain, uint16_t offset)
{
assert(q);
assert(domain);
assert(domain->number > 0);
if (offset > MAX_COMPRESSION_OFFSET)
return;
if (q->compressed_dname_count >= MAX_COMPRESSED_DNAMES)
return;
q->compressed_dname_offsets[domain->number] = offset;
q->compressed_dnames[q->compressed_dname_count] = domain;
++q->compressed_dname_count;
}
void
query_clear_dname_offsets(struct query *q, size_t max_offset)
{
while (q->compressed_dname_count > 0
&& (q->compressed_dname_offsets[q->compressed_dnames[q->compressed_dname_count - 1]->number]
>= max_offset))
{
q->compressed_dname_offsets[q->compressed_dnames[q->compressed_dname_count - 1]->number] = 0;
--q->compressed_dname_count;
}
}
void
query_clear_compression_tables(struct query *q)
{
uint16_t i;
for (i = 0; i < q->compressed_dname_count; ++i) {
assert(q->compressed_dnames);
q->compressed_dname_offsets[q->compressed_dnames[i]->number] = 0;
}
q->compressed_dname_count = 0;
}
void
query_add_compression_domain(struct query *q, domain_type *domain, uint16_t offset)
{
while (domain->parent) {
DEBUG(DEBUG_NAME_COMPRESSION, 2,
(LOG_INFO, "query dname: %s, number: %lu, offset: %u\n",
domain_to_string(domain),
(unsigned long) domain->number,
offset));
query_put_dname_offset(q, domain, offset);
offset += label_length(dname_name(domain_dname(domain))) + 1;
domain = domain->parent;
}
}
/*
* Generate an error response with the specified RCODE.
*/
query_state_type
query_error (struct query *q, nsd_rc_type rcode)
{
if (rcode == NSD_RC_DISCARD) {
return QUERY_DISCARDED;
}
buffer_clear(q->packet);
QR_SET(q->packet); /* This is an answer. */
AD_CLR(q->packet);
RCODE_SET(q->packet, (int) rcode); /* Error code. */
/* Truncate the question as well... */
QDCOUNT_SET(q->packet, 0);
ANCOUNT_SET(q->packet, 0);
NSCOUNT_SET(q->packet, 0);
ARCOUNT_SET(q->packet, 0);
buffer_set_position(q->packet, QHEADERSZ);
return QUERY_PROCESSED;
}
static int
query_ratelimit_err(nsd_type* nsd)
{
time_t now = time(NULL);
if(nsd->err_limit_time == now) {
/* see if limit is exceeded for this second */
if(nsd->err_limit_count++ > ERROR_RATELIMIT)
return 1;
} else {
/* new second, new limits */
nsd->err_limit_time = now;
nsd->err_limit_count = 1;
}
return 0;
}
static query_state_type
query_formerr (struct query *query, nsd_type* nsd)
{
int opcode = OPCODE(query->packet);
if(query_ratelimit_err(nsd))
return QUERY_DISCARDED;
FLAGS_SET(query->packet, FLAGS(query->packet) & 0x0100U);
/* Preserve the RD flag. Clear the rest. */
OPCODE_SET(query->packet, opcode);
return query_error(query, NSD_RC_FORMAT);
}
static void
query_cleanup(void *data)
{
query_type *query = (query_type *) data;
region_destroy(query->region);
}
query_type *
query_create(region_type *region, uint16_t *compressed_dname_offsets,
size_t compressed_dname_size, domain_type **compressed_dnames)
{
query_type *query
= (query_type *) region_alloc_zero(region, sizeof(query_type));
/* create region with large block size, because the initial chunk
saves many mallocs in the server */
query->region = region_create_custom(xalloc, free, 16384, 16384/8, 32, 0);
query->compressed_dname_offsets = compressed_dname_offsets;
query->compressed_dnames = compressed_dnames;
query->packet = buffer_create(region, QIOBUFSZ);
region_add_cleanup(region, query_cleanup, query);
query->compressed_dname_offsets_size = compressed_dname_size;
tsig_create_record(&query->tsig, region);
query->tsig_prepare_it = 1;
query->tsig_update_it = 1;
query->tsig_sign_it = 1;
return query;
}
void
query_reset(query_type *q, size_t maxlen, int is_tcp)
{
/*
* As long as less than 4Kb (region block size) has been used,
* this call to free_all is free, the block is saved for re-use,
* so no malloc() or free() calls are done.
* at present use of the region is for:
* o query qname dname_type (255 max).
* o wildcard expansion domain_type (7*ptr+u32+2bytes)+(5*ptr nsec3)
* o wildcard expansion for additional section domain_type.
* o nsec3 hashed name(s) (3 dnames for a nonexist_proof,
* one proof per wildcard and for nx domain).
*/
region_free_all(q->region);
q->remote_addrlen = (socklen_t)sizeof(q->remote_addr);
q->client_addrlen = (socklen_t)sizeof(q->client_addr);
q->is_proxied = 0;
q->maxlen = maxlen;
q->reserved_space = 0;
buffer_clear(q->packet);
edns_init_record(&q->edns);
tsig_init_record(&q->tsig, NULL, NULL);
q->tsig_prepare_it = 1;
q->tsig_update_it = 1;
q->tsig_sign_it = 1;
q->tcp = is_tcp;
q->qname = NULL;
q->qtype = 0;
q->qclass = 0;
q->zone = NULL;
q->opcode = 0;
q->cname_count = 0;
q->delegation_domain = NULL;
q->delegation_rrset = NULL;
q->compressed_dname_count = 0;
q->number_temporary_domains = 0;
q->axfr_is_done = 0;
q->axfr_zone = NULL;
q->axfr_current_domain = NULL;
q->axfr_current_rrset = NULL;
q->axfr_current_rr = 0;
q->ixfr_is_done = 0;
q->ixfr_data = NULL;
q->ixfr_count_newsoa = 0;
q->ixfr_count_oldsoa = 0;
q->ixfr_count_del = 0;
q->ixfr_count_add = 0;
#ifdef RATELIMIT
q->wildcard_domain = NULL;
#endif
}
/* get a temporary domain number (or 0=failure) */
static domain_type*
query_get_tempdomain(struct query *q)
{
static domain_type d[EXTRA_DOMAIN_NUMBERS];
if(q->number_temporary_domains >= EXTRA_DOMAIN_NUMBERS)
return 0;
q->number_temporary_domains ++;
memset(&d[q->number_temporary_domains-1], 0, sizeof(domain_type));
d[q->number_temporary_domains-1].number = q->compressed_dname_offsets_size +
q->number_temporary_domains - 1;
return &d[q->number_temporary_domains-1];
}
static void
query_addtxt(struct query *q,
const uint8_t *dname,
uint16_t klass,
uint32_t ttl,
const char *txt)
{
size_t txt_length = strlen(txt);
uint8_t len = (uint8_t) txt_length;
assert(txt_length <= UCHAR_MAX);
/* Add the dname */
if (dname >= buffer_begin(q->packet)
&& dname <= buffer_current(q->packet))
{
buffer_write_u16(q->packet,
0xc000 | (dname - buffer_begin(q->packet)));
} else {
buffer_write(q->packet, dname + 1, *dname);
}
buffer_write_u16(q->packet, TYPE_TXT);
buffer_write_u16(q->packet, klass);
buffer_write_u32(q->packet, ttl);
buffer_write_u16(q->packet, len + 1);
buffer_write_u8(q->packet, len);
buffer_write(q->packet, txt, len);
}
/*
* Parse the question section of a query. The normalized query name
* is stored in QUERY->name, the class in QUERY->klass, and the type
* in QUERY->type.
*/
static int
process_query_section(query_type *query)
{
uint8_t qnamebuf[MAXDOMAINLEN];
buffer_set_position(query->packet, QHEADERSZ);
/* Lets parse the query name and convert it to lower case. */
if(!packet_read_query_section(query->packet, qnamebuf,
&query->qtype, &query->qclass))
return 0;
query->qname = dname_make(query->region, qnamebuf, 1);
return 1;
}
/*
* Process an optional EDNS OPT record. Sets QUERY->EDNS to 0 if
* there was no EDNS record, to -1 if there was an invalid or
* unsupported EDNS record, and to 1 otherwise. Updates QUERY->MAXLEN
* if the EDNS record specifies a maximum supported response length.
*
* Return NSD_RC_FORMAT on failure, NSD_RC_OK on success.
*/
static nsd_rc_type
process_edns(nsd_type* nsd, struct query *q)
{
if (q->edns.status == EDNS_ERROR) {
/* The only error is VERSION not implemented */
return NSD_RC_FORMAT;
}
if (q->edns.status == EDNS_OK) {
/* Only care about UDP size larger than normal... */
if (!q->tcp && q->edns.maxlen > UDP_MAX_MESSAGE_LEN) {
size_t edns_size;
#if defined(INET6)
if (q->client_addr.ss_family == AF_INET6) {
edns_size = nsd->ipv6_edns_size;
} else
#endif
edns_size = nsd->ipv4_edns_size;
if (q->edns.maxlen < edns_size) {
q->maxlen = q->edns.maxlen;
} else {
q->maxlen = edns_size;
}
#if defined(INET6) && !defined(IPV6_USE_MIN_MTU) && !defined(IPV6_MTU)
/*
* Use IPv6 minimum MTU to avoid sending
* packets that are too large for some links.
* IPv6 will not automatically fragment in
* this case (unlike IPv4).
*/
if (q->client_addr.ss_family == AF_INET6
&& q->maxlen > IPV6_MIN_MTU)
{
q->maxlen = IPV6_MIN_MTU;
}
#endif
}
/* Strip the OPT resource record off... */
buffer_set_position(q->packet, q->edns.position);
buffer_set_limit(q->packet, q->edns.position);
ARCOUNT_SET(q->packet, ARCOUNT(q->packet) - 1);
}
return NSD_RC_OK;
}
/*
* Processes TSIG.
* Sets error when tsig does not verify on the query.
*/
static nsd_rc_type
process_tsig(struct query* q)
{
if(q->tsig.status == TSIG_ERROR)
return NSD_RC_FORMAT;
if(q->tsig.status == TSIG_OK) {
if(!tsig_from_query(&q->tsig)) {
char a[128];
addr2str(&q->client_addr, a, sizeof(a));
log_msg(LOG_ERR, "query: bad tsig (%s) for key %s from %s",
tsig_error(q->tsig.error_code),
dname_to_string(q->tsig.key_name, NULL), a);
return NSD_RC_NOTAUTH;
}
buffer_set_limit(q->packet, q->tsig.position);
ARCOUNT_SET(q->packet, ARCOUNT(q->packet) - 1);
tsig_prepare(&q->tsig);
tsig_update(&q->tsig, q->packet, buffer_limit(q->packet));
if(!tsig_verify(&q->tsig)) {
char a[128];
addr2str(&q->client_addr, a, sizeof(a));
log_msg(LOG_ERR, "query: bad tsig signature for key %s from %s",
dname_to_string(q->tsig.key->name, NULL), a);
return NSD_RC_NOTAUTH;
}
DEBUG(DEBUG_XFRD,1, (LOG_INFO, "query good tsig signature for %s",
dname_to_string(q->tsig.key->name, NULL)));
}
return NSD_RC_OK;
}
/*
* Check notify acl and forward to xfrd (or return an error).
*/
static query_state_type
answer_notify(struct nsd* nsd, struct query *query)
{
int acl_num, acl_num_xfr;
struct acl_options *why;
nsd_rc_type rc;
struct zone_options* zone_opt;
DEBUG(DEBUG_XFRD,1, (LOG_INFO, "got notify %s processing acl",
dname_to_string(query->qname, NULL)));
zone_opt = zone_options_find(nsd->options, query->qname);
if(!zone_opt)
return query_error(query, NSD_RC_NXDOMAIN);
if(!nsd->this_child) /* we are in debug mode or something */
return query_error(query, NSD_RC_SERVFAIL);
if(!tsig_find_rr(&query->tsig, query->packet)) {
DEBUG(DEBUG_XFRD,2, (LOG_ERR, "bad tsig RR format"));
return query_error(query, NSD_RC_FORMAT);
}
rc = process_tsig(query);
if(rc != NSD_RC_OK)
return query_error(query, rc);
/* check if it passes acl */
if(query->is_proxied && acl_check_incoming_block_proxy(
zone_opt->pattern->allow_notify, query, &why) == -1) {
/* the proxy address is blocked */
if (verbosity >= 2) {
char address[128], proxy[128];
addr2str(&query->client_addr, address, sizeof(address));
addr2str(&query->remote_addr, proxy, sizeof(proxy));
VERBOSITY(2, (LOG_INFO, "notify for %s from %s via proxy %s refused because of proxy, %s%s%s",
dname_to_string(query->qname, NULL),
address, proxy,
(why?why->ip_address_spec:""),
(why&&why->ip_address_spec[0]?" ":""),
(why ? ( why->nokey ? "NOKEY"
: why->blocked ? "BLOCKED"
: why->key_name )
: "no acl matches")));
}
return query_error(query, NSD_RC_REFUSE);
}
if((acl_num = acl_check_incoming(zone_opt->pattern->allow_notify, query,
&why)) != -1)
{
sig_atomic_t mode = NSD_PASS_TO_XFRD;
int s = nsd->this_child->parent_fd;
uint16_t sz;
uint32_t acl_send = htonl(acl_num);
uint32_t acl_xfr;
size_t pos;
/* Find priority candidate for request XFR. -1 if no match */
acl_num_xfr = acl_check_incoming(
zone_opt->pattern->request_xfr, query, NULL);
acl_xfr = htonl(acl_num_xfr);
assert(why);
DEBUG(DEBUG_XFRD,1, (LOG_INFO, "got notify %s passed acl %s %s",
dname_to_string(query->qname, NULL),
why->ip_address_spec,
why->nokey?"NOKEY":
(why->blocked?"BLOCKED":why->key_name)));
sz = buffer_limit(query->packet);
if(buffer_limit(query->packet) > MAX_PACKET_SIZE)
return query_error(query, NSD_RC_SERVFAIL);
/* forward to xfrd for processing
Note. Blocking IPC I/O, but acl is OK. */
sz = htons(sz);
if(!write_socket(s, &mode, sizeof(mode)) ||
!write_socket(s, &sz, sizeof(sz)) ||
!write_socket(s, buffer_begin(query->packet),
buffer_limit(query->packet)) ||
!write_socket(s, &acl_send, sizeof(acl_send)) ||
!write_socket(s, &acl_xfr, sizeof(acl_xfr))) {
log_msg(LOG_ERR, "error in IPC notify server2main, %s",
strerror(errno));
return query_error(query, NSD_RC_SERVFAIL);
}
if(verbosity >= 1) {
uint32_t serial = 0;
char address[128];
addr2str(&query->client_addr, address, sizeof(address));
if(packet_find_notify_serial(query->packet, &serial))
VERBOSITY(1, (LOG_INFO, "notify for %s from %s serial %u",
dname_to_string(query->qname, NULL), address,
(unsigned)serial));
else
VERBOSITY(1, (LOG_INFO, "notify for %s from %s",
dname_to_string(query->qname, NULL), address));
}
/* create notify reply - keep same query contents */
QR_SET(query->packet); /* This is an answer. */
AA_SET(query->packet); /* we are authoritative. */
ANCOUNT_SET(query->packet, 0);
NSCOUNT_SET(query->packet, 0);
ARCOUNT_SET(query->packet, 0);
RCODE_SET(query->packet, RCODE_OK); /* Error code. */
/* position is right after the query */
pos = buffer_position(query->packet);
buffer_clear(query->packet);
buffer_set_position(query->packet, pos);
/* tsig is added in add_additional later (if needed) */
return QUERY_PROCESSED;
}
if (verbosity >= 2) {
char address[128];
addr2str(&query->client_addr, address, sizeof(address));
VERBOSITY(2, (LOG_INFO, "notify for %s from %s refused, %s%s%s",
dname_to_string(query->qname, NULL),
address,
(why?why->ip_address_spec:""),
(why&&why->ip_address_spec[0]?" ":""),
(why ? ( why->nokey ? "NOKEY"
: why->blocked ? "BLOCKED"
: why->key_name )
: "no acl matches")));
}
return query_error(query, NSD_RC_REFUSE);
}
/*
* Answer a query in the CHAOS class.
*/
static query_state_type
answer_chaos(struct nsd *nsd, query_type *q)
{
AA_CLR(q->packet);
switch (q->qtype) {
case TYPE_ANY:
case TYPE_TXT:
if ((q->qname->name_size == 11
&& memcmp(dname_name(q->qname), "\002id\006server", 11) == 0) ||
(q->qname->name_size == 15
&& memcmp(dname_name(q->qname), "\010hostname\004bind", 15) == 0))
{
if(!nsd->options->hide_identity) {
/* Add ID */
query_addtxt(q,
buffer_begin(q->packet) + QHEADERSZ,
CLASS_CH,
0,
nsd->identity);
ANCOUNT_SET(q->packet, ANCOUNT(q->packet) + 1);
} else {
RCODE_SET(q->packet, RCODE_REFUSE);
/* RFC8914 - Extended DNS Errors
* 4.19. Extended DNS Error Code 18 - Prohibited */
q->edns.ede = EDE_PROHIBITED;
}
} else if ((q->qname->name_size == 16
&& memcmp(dname_name(q->qname), "\007version\006server", 16) == 0) ||
(q->qname->name_size == 14
&& memcmp(dname_name(q->qname), "\007version\004bind", 14) == 0))
{
if(!nsd->options->hide_version) {
/* Add version */
query_addtxt(q,
buffer_begin(q->packet) + QHEADERSZ,
CLASS_CH,
0,
nsd->version);
ANCOUNT_SET(q->packet, ANCOUNT(q->packet) + 1);
} else {
RCODE_SET(q->packet, RCODE_REFUSE);
/* RFC8914 - Extended DNS Errors
* 4.19. Extended DNS Error Code 18 - Prohibited */
q->edns.ede = EDE_PROHIBITED;
}
} else {
RCODE_SET(q->packet, RCODE_REFUSE);
/* RFC8914 - Extended DNS Errors
* 4.22. Extended DNS Error Code 21 - Not Supported */
q->edns.ede = EDE_NOT_SUPPORTED;
}
break;
default:
RCODE_SET(q->packet, RCODE_REFUSE);
/* RFC8914 - Extended DNS Errors
* 4.22. Extended DNS Error Code 21 - Not Supported */
q->edns.ede = EDE_NOT_SUPPORTED;
break;
}
return QUERY_PROCESSED;
}
/*
* Find the covering NSEC for a non-existent domain name. Normally
* the NSEC will be located at CLOSEST_MATCH, except when it is an
* empty non-terminal. In this case the NSEC may be located at the
* previous domain name (in canonical ordering).
*/
static domain_type *
find_covering_nsec(domain_type *closest_match,
zone_type *zone,
rrset_type **nsec_rrset)
{
assert(closest_match);
assert(nsec_rrset);
/* loop away temporary created domains. For real ones it is &RBTREE_NULL */
#ifdef USE_RADIX_TREE
while (closest_match->rnode == NULL)
#else
while (closest_match->node.parent == NULL)
#endif
closest_match = closest_match->parent;
while (closest_match) {
*nsec_rrset = domain_find_rrset(closest_match, zone, TYPE_NSEC);
if (*nsec_rrset) {
return closest_match;
}
if (closest_match == zone->apex) {
/* Don't look outside the current zone. */
return NULL;
}
closest_match = domain_previous(closest_match);
}
return NULL;
}
struct additional_rr_types
{
uint16_t rr_type;
rr_section_type rr_section;
};
struct additional_rr_types default_additional_rr_types[] = {
{ TYPE_A, ADDITIONAL_A_SECTION },
{ TYPE_AAAA, ADDITIONAL_AAAA_SECTION },
{ 0, (rr_section_type) 0 }
};
struct additional_rr_types swap_aaaa_additional_rr_types[] = {
{ TYPE_AAAA, ADDITIONAL_A_SECTION },
{ TYPE_A, ADDITIONAL_AAAA_SECTION },
{ 0, (rr_section_type) 0 }
};
struct additional_rr_types rt_additional_rr_types[] = {
{ TYPE_A, ADDITIONAL_A_SECTION },
{ TYPE_AAAA, ADDITIONAL_AAAA_SECTION },
{ TYPE_X25, ADDITIONAL_OTHER_SECTION },
{ TYPE_ISDN, ADDITIONAL_OTHER_SECTION },
{ 0, (rr_section_type) 0 }
};
static void
add_additional_rrsets(struct query *query, answer_type *answer,
rrset_type *master_rrset, size_t rdata_index,
int allow_glue, struct additional_rr_types types[])
{
size_t i;
assert(query);
assert(answer);
assert(master_rrset);
assert(rdata_atom_is_domain(rrset_rrtype(master_rrset), rdata_index));
for (i = 0; i < master_rrset->rr_count; ++i) {
int j;
domain_type *additional = rdata_atom_domain(master_rrset->rrs[i].rdatas[rdata_index]);
domain_type *match = additional;
assert(additional);
if (!allow_glue && domain_is_glue(match, query->zone))
continue;
/*
* Check to see if we need to generate the dependent
* based on a wildcard domain.
*/
while (!match->is_existing) {
match = match->parent;
}
if (additional != match && domain_wildcard_child(match)) {
domain_type *wildcard_child = domain_wildcard_child(match);
domain_type *temp = (domain_type *) region_alloc(
query->region, sizeof(domain_type));
#ifdef USE_RADIX_TREE
temp->rnode = NULL;
temp->dname = additional->dname;
#else
memcpy(&temp->node, &additional->node, sizeof(rbnode_type));
temp->node.parent = NULL;
#endif
temp->number = additional->number;
temp->parent = match;
temp->wildcard_child_closest_match = temp;
temp->rrsets = wildcard_child->rrsets;
temp->is_existing = wildcard_child->is_existing;
additional = temp;
}
for (j = 0; types[j].rr_type != 0; ++j) {
rrset_type *rrset = domain_find_rrset(
additional, query->zone, types[j].rr_type);
if (rrset) {
answer_add_rrset(answer, types[j].rr_section,
additional, rrset);
}
}
}
}
static int
answer_needs_ns(struct query* query)
{
assert(query);
/* Currently, only troublesome for DNSKEY and DS,
* cuz their RRSETs are quite large. */
return (query->qtype != TYPE_DNSKEY && query->qtype != TYPE_DS
&& query->qtype != TYPE_ANY);
}
static int
add_rrset(struct query *query,
answer_type *answer,
rr_section_type section,
domain_type *owner,
rrset_type *rrset)
{
int result;
assert(query);
assert(answer);
assert(owner);
assert(rrset);
assert(rrset_rrclass(rrset) == CLASS_IN);
result = answer_add_rrset(answer, section, owner, rrset);
if(minimal_responses && section != AUTHORITY_SECTION &&
query->qtype != TYPE_NS)
return result;
switch (rrset_rrtype(rrset)) {
case TYPE_NS:
#if defined(INET6)
/* if query over IPv6, swap A and AAAA; put AAAA first */
add_additional_rrsets(query, answer, rrset, 0, 1,
(query->client_addr.ss_family == AF_INET6)?
swap_aaaa_additional_rr_types:
default_additional_rr_types);
#else
add_additional_rrsets(query, answer, rrset, 0, 1,
default_additional_rr_types);
#endif
break;
case TYPE_MB:
add_additional_rrsets(query, answer, rrset, 0, 0,
default_additional_rr_types);
break;
case TYPE_MX:
case TYPE_KX:
add_additional_rrsets(query, answer, rrset, 1, 0,
default_additional_rr_types);
break;
case TYPE_RT:
add_additional_rrsets(query, answer, rrset, 1, 0,
rt_additional_rr_types);
break;
case TYPE_SRV:
add_additional_rrsets(query, answer, rrset, 3, 0,
default_additional_rr_types);
break;
default:
break;
}
return result;
}
/* returns 0 on error, or the domain number for to_name.
from_name is changes to to_name by the DNAME rr.
DNAME rr is from src to dest.
closest encloser encloses the to_name. */
static size_t
query_synthesize_cname(struct query* q, struct answer* answer, const dname_type* from_name,
const dname_type* to_name, domain_type* src, domain_type* to_closest_encloser,
domain_type** to_closest_match, uint32_t ttl)
{
/* add temporary domains for from_name and to_name and all
their (not allocated yet) parents */
/* any domains below src are not_existing (because of DNAME at src) */
int i;
size_t j;
domain_type* cname_domain;
domain_type* cname_dest;
rrset_type* rrset;
domain_type* lastparent = src;
assert(q && answer && from_name && to_name && src && to_closest_encloser);
assert(to_closest_match);
/* check for loop by duplicate CNAME rrset synthesized */
for(j=0; j<answer->rrset_count; ++j) {
if(answer->section[j] == ANSWER_SECTION &&
answer->rrsets[j]->rr_count == 1 &&
answer->rrsets[j]->rrs[0].type == TYPE_CNAME &&
dname_compare(domain_dname(answer->rrsets[j]->rrs[0].owner), from_name) == 0 &&
answer->rrsets[j]->rrs[0].rdata_count == 1 &&
dname_compare(domain_dname(answer->rrsets[j]->rrs[0].rdatas->domain), to_name) == 0) {
DEBUG(DEBUG_QUERY,2, (LOG_INFO, "loop for synthesized CNAME rrset for query %s", dname_to_string(q->qname, NULL)));
return 0;
}
}
/* allocate source part */
for(i=0; i < from_name->label_count - domain_dname(src)->label_count; i++)
{
domain_type* newdom = query_get_tempdomain(q);
if(!newdom)
return 0;
newdom->is_existing = 1;
newdom->parent = lastparent;
#ifdef USE_RADIX_TREE
newdom->dname
#else
newdom->node.key
#endif
= dname_partial_copy(q->region,
from_name, domain_dname(src)->label_count + i + 1);
if(dname_compare(domain_dname(newdom), q->qname) == 0) {
/* 0 good for query name, otherwise new number */
newdom->number = 0;
}
DEBUG(DEBUG_QUERY,2, (LOG_INFO, "created temp domain src %d. %s nr %d", i,
domain_to_string(newdom), (int)newdom->number));
lastparent = newdom;
}
cname_domain = lastparent;
/* allocate dest part */
lastparent = to_closest_encloser;
for(i=0; i < to_name->label_count - domain_dname(to_closest_encloser)->label_count;
i++)
{
domain_type* newdom = query_get_tempdomain(q);
if(!newdom)
return 0;
newdom->is_existing = 0;
newdom->parent = lastparent;
#ifdef USE_RADIX_TREE
newdom->dname
#else
newdom->node.key
#endif
= dname_partial_copy(q->region,
to_name, domain_dname(to_closest_encloser)->label_count + i + 1);
DEBUG(DEBUG_QUERY,2, (LOG_INFO, "created temp domain dest %d. %s nr %d", i,
domain_to_string(newdom), (int)newdom->number));
lastparent = newdom;
}
cname_dest = lastparent;
*to_closest_match = cname_dest;
/* allocate the CNAME RR */
rrset = (rrset_type*) region_alloc(q->region, sizeof(rrset_type));
memset(rrset, 0, sizeof(rrset_type));
rrset->zone = q->zone;
rrset->rr_count = 1;
rrset->rrs = (rr_type*) region_alloc(q->region, sizeof(rr_type));
memset(rrset->rrs, 0, sizeof(rr_type));
rrset->rrs->owner = cname_domain;
rrset->rrs->ttl = ttl;
rrset->rrs->type = TYPE_CNAME;
rrset->rrs->klass = CLASS_IN;
rrset->rrs->rdata_count = 1;
rrset->rrs->rdatas = (rdata_atom_type*)region_alloc(q->region,
sizeof(rdata_atom_type));
rrset->rrs->rdatas->domain = cname_dest;
if(!add_rrset(q, answer, ANSWER_SECTION, cname_domain, rrset)) {
DEBUG(DEBUG_QUERY,2, (LOG_INFO, "could not add synthesized CNAME rrset to packet for query %s", dname_to_string(q->qname, NULL)));
/* failure to add CNAME; likely is a loop, the same twice */
return 0;
}
return cname_dest->number;
}
/*
* Answer delegation information.
*
* DNSSEC: Include the DS RRset if present. Otherwise include an NSEC
* record proving the DS RRset does not exist.
*/
static void
answer_delegation(query_type *query, answer_type *answer)
{
assert(answer);
assert(query->delegation_domain);
assert(query->delegation_rrset);
if (query->cname_count == 0) {
AA_CLR(query->packet);
} else {
AA_SET(query->packet);
}
add_rrset(query,
answer,
AUTHORITY_SECTION,
query->delegation_domain,
query->delegation_rrset);
if (query->edns.dnssec_ok && zone_is_secure(query->zone)) {
rrset_type *rrset;
if ((rrset = domain_find_rrset(query->delegation_domain, query->zone, TYPE_DS))) {
add_rrset(query, answer, AUTHORITY_SECTION,
query->delegation_domain, rrset);
#ifdef NSEC3
} else if (query->zone->nsec3_param) {
nsec3_answer_delegation(query, answer);
#endif
} else if ((rrset = domain_find_rrset(query->delegation_domain, query->zone, TYPE_NSEC))) {
add_rrset(query, answer, AUTHORITY_SECTION,
query->delegation_domain, rrset);
}
}
}
/*
* Answer SOA information.
*/
static void
answer_soa(struct query *query, answer_type *answer)
{
if (query->qclass != CLASS_ANY) {
add_rrset(query, answer,
AUTHORITY_SECTION,
query->zone->apex,
query->zone->soa_nx_rrset);
}
}
/*
* Answer that the domain name exists but there is no RRset with the
* requested type.
*
* DNSSEC: Include the correct NSEC record proving that the type does
* not exist. In the wildcard no data (3.1.3.4) case the wildcard IS
* NOT expanded, so the ORIGINAL parameter must point to the original
* wildcard entry, not to the generated entry.
*/
static void
answer_nodata(struct query *query, answer_type *answer, domain_type *original)
{
answer_soa(query, answer);
#ifdef NSEC3
if (query->edns.dnssec_ok && query->zone->nsec3_param) {
nsec3_answer_nodata(query, answer, original);
} else
#endif
if (query->edns.dnssec_ok && zone_is_secure(query->zone)) {
domain_type *nsec_domain;
rrset_type *nsec_rrset;
nsec_domain = find_covering_nsec(original, query->zone, &nsec_rrset);
if (nsec_domain) {
add_rrset(query, answer, AUTHORITY_SECTION, nsec_domain, nsec_rrset);
}
}
}