forked from jech/polipo
-
Notifications
You must be signed in to change notification settings - Fork 0
/
dns.c
1691 lines (1531 loc) · 48 KB
/
dns.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
/*
Copyright (c) 2003-2006 by Juliusz Chroboczek
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/
#include "polipo.h"
#ifndef NO_STANDARD_RESOLVER
#ifndef NO_FANCY_RESOLVER
int dnsUseGethostbyname = 1;
#else
const int dnsUseGethostbyname = 3;
#endif
#else
#ifndef NO_FANCY_RESOLVER
const int dnsUseGethostbyname = 0;
#else
#error use no resolver at all?
#endif
#endif
#ifndef NO_FANCY_RESOLVER
AtomPtr dnsNameServer = NULL;
int dnsMaxTimeout = 60;
#endif
#ifndef NO_STANDARD_RESOLVER
int dnsGethostbynameTtl = 1200;
#endif
int dnsNegativeTtl = 120;
#ifdef HAVE_IPv6
int dnsQueryIPv6 = 2;
#else
const int dnsQueryIPv6 = 0;
#endif
typedef struct _DnsQuery {
unsigned id;
AtomPtr name;
ObjectPtr object;
AtomPtr inet4, inet6;
time_t ttl4, ttl6;
time_t time;
int timeout;
TimeEventHandlerPtr timeout_handler;
struct _DnsQuery *next;
} DnsQueryRec, *DnsQueryPtr;
union {
struct sockaddr sa;
struct sockaddr_in sin;
#ifdef HAVE_IPv6
struct sockaddr_in6 sin6;
#endif
} nameserverAddress_storage;
#ifndef NO_FANCY_RESOLVER
#define nameserverAddress nameserverAddress_storage.sa
static DnsQueryPtr inFlightDnsQueries;
static DnsQueryPtr inFlightDnsQueriesLast;
#endif
static int really_do_gethostbyname(AtomPtr name, ObjectPtr object);
static int really_do_dns(AtomPtr name, ObjectPtr object);
#ifndef NO_FANCY_RESOLVER
static int stringToLabels(char *buf, int offset, int n, char *string);
static int labelsToString(char *buf, int offset, int n, char *d,
int m, int *j_return);
static int dnsBuildQuery(int id, char *buf, int offset, int n,
AtomPtr name, int af);
static int dnsReplyHandler(int abort, FdEventHandlerPtr event);
static int dnsReplyId(char *buf, int offset, int n, int *id_return);
static int dnsDecodeReply(char *buf, int offset, int n,
int *id_return,
AtomPtr *name_return, AtomPtr *value_return,
int *af_return, unsigned *ttl_return);
static int dnsHandler(int status, ConditionHandlerPtr chandler);
static int dnsGethostbynameFallback(int id, AtomPtr message);
static int sendQuery(DnsQueryPtr query);
static int idSeed;
#endif
#ifndef NO_FANCY_RESOLVER
static int
parseResolvConf(char *filename)
{
FILE *f;
char buf[512];
char *p, *q;
int n;
AtomPtr nameserver = NULL;
f = fopen(filename, "r");
if(f == NULL) {
do_log_error(L_ERROR, errno, "DNS: couldn't open %s", filename);
return 0;
}
while(1) {
p = fgets(buf, 512, f);
if(p == NULL)
break;
n = strlen(buf);
if(buf[n - 1] != '\n') {
int c;
do_log(L_WARN, "DNS: overly long line in %s -- skipping.\n",
filename);
do {
c = fgetc(f);
if(c == EOF)
break;
} while(c != '\n');
if(c == EOF)
break;
}
while(*p == ' ' || *p == '\t')
p++;
if(strcasecmp_n("nameserver", p, 10) != 0)
continue;
p += 10;
while(*p == ' ' || *p == '\t')
p++;
q = p;
while(*q == '.' || *q == ':' || digit(*q) || letter(*q))
q++;
if(*q != ' ' && *q != '\t' && *q != '\r' && *q != '\n') {
do_log(L_WARN, "DNS: couldn't parse line in %s -- skipping.\n",
filename);
continue;
}
nameserver = internAtomLowerN(p, q - p);
break;
}
fclose(f);
if(nameserver) {
dnsNameServer = nameserver;
return 1;
} else {
return 0;
}
}
#endif
void
preinitDns()
{
#ifdef HAVE_IPv6
int fd;
#endif
assert(sizeof(struct in_addr) == 4);
#ifdef HAVE_IPv6
assert(sizeof(struct in6_addr) == 16);
#endif
#ifndef NO_STANDARD_RESOLVER
CONFIG_VARIABLE(dnsGethostbynameTtl, CONFIG_TIME,
"TTL for gethostbyname addresses.");
#endif
#ifdef HAVE_IPv6
fd = socket(PF_INET6, SOCK_STREAM, 0);
if(fd < 0) {
if(errno == EPROTONOSUPPORT || errno == EAFNOSUPPORT) {
dnsQueryIPv6 = 0;
} else {
do_log_error(L_WARN, errno, "DNS: couldn't create socket");
}
} else {
close(fd);
}
#endif
#ifndef NO_FANCY_RESOLVER
parseResolvConf("/etc/resolv.conf");
if(dnsNameServer == NULL || dnsNameServer->string[0] == '\0')
dnsNameServer = internAtom("127.0.0.1");
CONFIG_VARIABLE(dnsMaxTimeout, CONFIG_TIME,
"Max timeout for DNS queries.");
CONFIG_VARIABLE(dnsNegativeTtl, CONFIG_TIME,
"TTL for negative DNS replies with no TTL.");
CONFIG_VARIABLE(dnsNameServer, CONFIG_ATOM_LOWER,
"The name server to use.");
#ifndef NO_STANDARD_RESOLVER
CONFIG_VARIABLE(dnsUseGethostbyname, CONFIG_TETRASTATE,
"Use the system resolver.");
#endif
#endif
#ifdef HAVE_IPv6
CONFIG_VARIABLE(dnsQueryIPv6, CONFIG_TETRASTATE,
"Query for IPv6 addresses.");
#endif
}
void
initDns()
{
#ifndef NO_FANCY_RESOLVER
int rc;
struct timeval t;
struct sockaddr_in *sin = (struct sockaddr_in*)&nameserverAddress;
#ifdef HAVE_IPv6
struct sockaddr_in6 *sin6 = (struct sockaddr_in6*)&nameserverAddress;
#endif
inFlightDnsQueries = NULL;
inFlightDnsQueriesLast = NULL;
gettimeofday(&t, NULL);
idSeed = t.tv_usec & 0xFFFF;
sin->sin_family = AF_INET;
sin->sin_port = htons(53);
rc = inet_aton(dnsNameServer->string, &sin->sin_addr);
#ifdef HAVE_IPv6
if(rc != 1) {
sin6->sin6_family = AF_INET6;
sin6->sin6_port = htons(53);
rc = inet_pton(AF_INET6, dnsNameServer->string, &sin6->sin6_addr);
}
#endif
if(rc != 1) {
do_log(L_ERROR, "DNS: couldn't parse name server %s.\n",
dnsNameServer->string);
exit(1);
}
#endif
}
int
do_gethostbyname(char *origname,
int count,
int (*handler)(int, GethostbynameRequestPtr),
void *data)
{
ObjectPtr object;
int n = strlen(origname);
AtomPtr name;
GethostbynameRequestRec request;
int done, rc;
memset(&request, 0, sizeof(request));
request.name = NULL;
request.addr = NULL;
request.error_message = NULL;
request.count = count;
request.handler = handler;
request.data = data;
if(n <= 0 || n > 131) {
if(n <= 0) {
request.error_message = internAtom("empty name");
do_log(L_ERROR, "Empty DNS name.\n");
done = handler(-EINVAL, &request);
} else {
request.error_message = internAtom("name too long");
do_log(L_ERROR, "DNS name too long.\n");
done = handler(-ENAMETOOLONG, &request);
}
assert(done);
releaseAtom(request.error_message);
return 1;
}
if(origname[n - 1] == '.')
n--;
name = internAtomLowerN(origname, n);
if(name == NULL) {
request.error_message = internAtom("couldn't allocate name");
do_log(L_ERROR, "Couldn't allocate DNS name.\n");
done = handler(-ENOMEM, &request);
assert(done);
releaseAtom(request.error_message);
return 1;
}
request.name = name;
request.addr = NULL;
request.error_message = NULL;
request.count = count;
request.object = NULL;
request.handler = handler;
request.data = data;
object = findObject(OBJECT_DNS, name->string, name->length);
if(object == NULL || objectMustRevalidate(object, NULL)) {
if(object) {
privatiseObject(object, 0);
releaseObject(object);
}
object = makeObject(OBJECT_DNS, name->string, name->length, 1, 0,
NULL, NULL);
if(object == NULL) {
request.error_message = internAtom("Couldn't allocate object");
do_log(L_ERROR, "Couldn't allocate DNS object.\n");
done = handler(-ENOMEM, &request);
assert(done);
releaseAtom(name);
releaseAtom(request.error_message);
return 1;
}
}
if((object->flags & (OBJECT_INITIAL | OBJECT_INPROGRESS)) ==
OBJECT_INITIAL) {
if(dnsUseGethostbyname >= 3)
rc = really_do_gethostbyname(name, object);
else
rc = really_do_dns(name, object);
if(rc < 0) {
assert(!(object->flags & (OBJECT_INITIAL | OBJECT_INPROGRESS)));
goto fail;
}
}
if(dnsUseGethostbyname >= 3)
assert(!(object->flags & OBJECT_INITIAL));
#ifndef NO_FANCY_RESOLVER
if(object->flags & OBJECT_INITIAL) {
ConditionHandlerPtr chandler;
assert(object->flags & OBJECT_INPROGRESS);
request.object = object;
chandler = conditionWait(&object->condition, dnsHandler,
sizeof(request), &request);
if(chandler == NULL) {
rc = ENOMEM;
goto fail;
}
return 1;
}
#endif
if(object->headers && object->headers->length > 0) {
if(object->headers->string[0] == DNS_A)
assert(((object->headers->length - 1) %
sizeof(HostAddressRec)) == 0);
else
assert(object->headers->string[0] == DNS_CNAME);
request.addr = retainAtom(object->headers);
} else if(object->message) {
request.error_message = retainAtom(object->message);
}
releaseObject(object);
if(request.addr && request.addr->length > 0)
done = handler(1, &request);
else
done = handler(-EDNS_HOST_NOT_FOUND, &request);
assert(done);
releaseAtom(request.addr); request.addr = NULL;
releaseAtom(request.name); request.name = NULL;
releaseAtom(request.error_message); request.error_message = NULL;
return 1;
fail:
releaseNotifyObject(object);
done = handler(-errno, &request);
assert(done);
releaseAtom(name);
return 1;
}
static int
dnsDelayedErrorNotifyHandler(TimeEventHandlerPtr event)
{
int done;
GethostbynameRequestRec request =
*(GethostbynameRequestPtr)event->data;
done = request.handler(-EDNS_HOST_NOT_FOUND, &request);
assert(done);
releaseAtom(request.name); request.name = NULL;
releaseAtom(request.addr); request.addr = NULL;
releaseAtom(request.error_message); request.error_message = NULL;
return 1;
}
static int
dnsDelayedDoneNotifyHandler(TimeEventHandlerPtr event)
{
int done;
GethostbynameRequestRec request = *(GethostbynameRequestPtr)event->data;
done = request.handler(1, &request);
assert(done);
releaseAtom(request.name); request.name = NULL;
releaseAtom(request.addr); request.addr = NULL;
releaseAtom(request.error_message); request.error_message = NULL;
return 1;
}
static int
dnsDelayedNotify(int error, GethostbynameRequestPtr request)
{
TimeEventHandlerPtr handler;
if(error)
handler = scheduleTimeEvent(0,
dnsDelayedErrorNotifyHandler,
sizeof(*request), request);
else
handler = scheduleTimeEvent(0,
dnsDelayedDoneNotifyHandler,
sizeof(*request), request);
if(handler == NULL) {
do_log(L_ERROR, "Couldn't schedule DNS notification.\n");
return -1;
}
return 1;
}
#ifdef HAVE_IPv6
AtomPtr
rfc2732(AtomPtr name)
{
char buf[38];
int rc;
AtomPtr a = NULL;
if(name->length < 38 &&
name->string[0] == '[' && name->string[name->length - 1] == ']') {
struct in6_addr in6a;
memcpy(buf, name->string + 1, name->length - 2);
buf[name->length - 2] = '\0';
rc = inet_pton(AF_INET6, buf, &in6a);
if(rc == 1) {
char s[1 + sizeof(HostAddressRec)];
memset(s, 0, sizeof(s));
s[0] = DNS_A;
s[1] = 6;
memcpy(s + 2, &in6a, 16);
a = internAtomN(s, 1 + sizeof(HostAddressRec));
if(a == NULL)
return NULL;
}
}
return a;
}
/* Used for sorting host addresses depending on the value of dnsQueryIPv6 */
int
compare_hostaddr(const void *av, const void *bv)
{
const HostAddressRec *a = av, *b = bv;
int r;
if(a->af == 4) {
if(b->af == 4)
r = 0;
else
r = -1;
} else {
if(b->af == 6)
r = 0;
else
r = 1;
}
if(dnsQueryIPv6 >= 2)
return -r;
else
return r;
}
#ifndef NO_STANDARD_RESOLVER
static int
really_do_gethostbyname(AtomPtr name, ObjectPtr object)
{
struct addrinfo *ai, *entry, hints;
int rc;
int error, i;
char buf[1024];
AtomPtr a;
a = rfc2732(name);
if(a) {
object->headers = a;
object->age = current_time.tv_sec;
object->expires = current_time.tv_sec + 240;
object->flags &= ~(OBJECT_INITIAL | OBJECT_INPROGRESS);
notifyObject(object);
return 0;
}
memset(&hints, 0, sizeof(hints));
hints.ai_protocol = IPPROTO_TCP;
if(dnsQueryIPv6 <= 0)
hints.ai_family = AF_INET;
else if(dnsQueryIPv6 >= 3)
hints.ai_family = AF_INET6;
rc = getaddrinfo(name->string, NULL, &hints, &ai);
switch(rc) {
case 0: error = 0; break;
case EAI_FAMILY:
#ifdef EAI_ADDRFAMILY
case EAI_ADDRFAMILY:
#endif
case EAI_SOCKTYPE:
error = EAFNOSUPPORT; break;
case EAI_BADFLAGS: error = EINVAL; break;
case EAI_SERVICE: error = EDNS_NO_RECOVERY; break;
#ifdef EAI_NONAME
case EAI_NONAME:
#endif
#ifdef EAI_NODATA
case EAI_NODATA:
#endif
error = EDNS_NO_ADDRESS; break;
case EAI_FAIL: error = EDNS_NO_RECOVERY; break;
case EAI_AGAIN: error = EDNS_TRY_AGAIN; break;
#ifdef EAI_MEMORY
case EAI_MEMORY: error = ENOMEM; break;
#endif
case EAI_SYSTEM: error = errno; break;
default: error = EUNKNOWN;
}
if(error == EDNS_NO_ADDRESS) {
object->headers = NULL;
object->age = current_time.tv_sec;
object->expires = current_time.tv_sec + dnsNegativeTtl;
object->flags &= ~(OBJECT_INITIAL | OBJECT_INPROGRESS);
notifyObject(object);
return 0;
} else if(error) {
do_log_error(L_ERROR, error, "Getaddrinfo failed");
object->flags &= ~OBJECT_INPROGRESS;
abortObject(object, 404,
internAtomError(error, "Getaddrinfo failed"));
notifyObject(object);
return 0;
}
entry = ai;
buf[0] = DNS_A;
i = 0;
while(entry) {
HostAddressRec host;
int host_valid = 0;
if(entry->ai_family == AF_INET && entry->ai_protocol == IPPROTO_TCP) {
if(dnsQueryIPv6 < 3) {
host.af = 4;
memset(host.data, 0, sizeof(host.data));
memcpy(&host.data,
&((struct sockaddr_in*)entry->ai_addr)->sin_addr,
4);
host_valid = 1;
}
} else if(entry->ai_family == AF_INET6 &&
entry->ai_protocol == IPPROTO_TCP) {
if(dnsQueryIPv6 > 0) {
host.af = 6;
memset(&host.data, 0, sizeof(host.data));
memcpy(&host.data,
&((struct sockaddr_in6*)entry->ai_addr)->sin6_addr,
16);
host_valid = 1;
}
}
if(host_valid) {
if(i >= 1024 / sizeof(HostAddressRec) - 2) {
do_log(L_ERROR, "Too many addresses for host %s\n",
name->string);
break;
}
memcpy(buf + 1 + i * sizeof(HostAddressRec),
&host, sizeof(HostAddressRec));
i++;
}
entry = entry->ai_next;
}
freeaddrinfo(ai);
if(i == 0) {
do_log(L_ERROR, "Getaddrinfo returned no useful addresses\n");
object->flags &= ~OBJECT_INPROGRESS;
abortObject(object, 404,
internAtom("Getaddrinfo returned no useful addresses"));
notifyObject(object);
return 0;
}
if(1 <= dnsQueryIPv6 && dnsQueryIPv6 <= 2)
qsort(buf + 1, i, sizeof(HostAddressRec), compare_hostaddr);
a = internAtomN(buf, 1 + i * sizeof(HostAddressRec));
if(a == NULL) {
object->flags &= ~OBJECT_INPROGRESS;
abortObject(object, 501, internAtom("Couldn't allocate address"));
notifyObject(object);
return 0;
}
object->headers = a;
object->age = current_time.tv_sec;
object->expires = current_time.tv_sec + dnsGethostbynameTtl;
object->flags &= ~(OBJECT_INITIAL | OBJECT_INPROGRESS);
notifyObject(object);
return 0;
}
#endif
#else
#ifndef NO_STANDARD_RESOLVER
static int
really_do_gethostbyname(AtomPtr name, ObjectPtr object)
{
struct hostent *host;
char *s;
AtomPtr a;
int i, j;
int error;
host = gethostbyname(name->string);
if(host == NULL) {
switch(h_errno) {
case HOST_NOT_FOUND: error = EDNS_HOST_NOT_FOUND; break;
case NO_ADDRESS: error = EDNS_NO_ADDRESS; break;
case NO_RECOVERY: error = EDNS_NO_RECOVERY; break;
case TRY_AGAIN: error = EDNS_TRY_AGAIN; break;
default: error = EUNKNOWN; break;
}
if(error == EDNS_HOST_NOT_FOUND) {
object->headers = NULL;
object->age = current_time.tv_sec;
object->expires = current_time.tv_sec + dnsNegativeTtl;
object->flags &= ~(OBJECT_INITIAL | OBJECT_INPROGRESS);
object->flags &= ~OBJECT_INPROGRESS;
notifyObject(object);
return 0;
} else {
do_log_error(L_ERROR, error, "Gethostbyname failed");
abortObject(object, 404,
internAtomError(error, "Gethostbyname failed"));
object->flags &= ~OBJECT_INPROGRESS;
notifyObject(object);
return 0;
}
}
if(host->h_addrtype != AF_INET) {
do_log(L_ERROR, "Address is not AF_INET.\n");
object->flags &= ~OBJECT_INPROGRESS;
abortObject(object, 404, internAtom("Address is not AF_INET"));
notifyObject(object);
return -1;
}
if(host->h_length != sizeof(struct in_addr)) {
do_log(L_ERROR, "Address size inconsistent.\n");
object->flags &= ~OBJECT_INPROGRESS;
abortObject(object, 404, internAtom("Address size inconsistent"));
notifyObject(object);
return 0;
}
i = 0;
while(host->h_addr_list[i] != NULL) i++;
s = malloc(1 + i * sizeof(HostAddressRec));
if(s == NULL) {
a = NULL;
} else {
memset(s, 0, 1 + i * sizeof(HostAddressRec));
s[0] = DNS_A;
for(j = 0; j < i; j++) {
s[j * sizeof(HostAddressRec) + 1] = 4;
memcpy(&s[j * sizeof(HostAddressRec) + 2], host->h_addr_list[j],
sizeof(struct in_addr));
}
a = internAtomN(s, i * sizeof(HostAddressRec) + 1);
free(s);
}
if(!a) {
object->flags &= ~OBJECT_INPROGRESS;
abortObject(object, 501, internAtom("Couldn't allocate address"));
notifyObject(object);
return 0;
}
object->headers = a;
object->age = current_time.tv_sec;
object->expires = current_time.tv_sec + dnsGethostbynameTtl;
object->flags &= ~(OBJECT_INITIAL | OBJECT_INPROGRESS);
notifyObject(object);
return 0;
}
#endif
#endif
#ifdef NO_STANDARD_RESOLVER
static int
really_do_gethostbyname(AtomPtr name, ObjectPtr object)
{
abort();
}
#endif
#ifndef NO_FANCY_RESOLVER
static int dnsSocket = -1;
static FdEventHandlerPtr dnsSocketHandler = NULL;
static int
dnsHandler(int status, ConditionHandlerPtr chandler)
{
GethostbynameRequestRec request = *(GethostbynameRequestPtr)chandler->data;
ObjectPtr object = request.object;
assert(!(object->flags & OBJECT_INPROGRESS));
if(object->headers) {
request.addr = retainAtom(object->headers);
dnsDelayedNotify(0, &request);
} else {
if(object->message)
request.error_message = retainAtom(object->message);
dnsDelayedNotify(1, &request);
}
releaseObject(object);
return 1;
}
static void
removeQuery(DnsQueryPtr query)
{
DnsQueryPtr previous;
if(query == inFlightDnsQueries) {
inFlightDnsQueries = query->next;
if(inFlightDnsQueries == NULL)
inFlightDnsQueriesLast = NULL;
} else {
previous = inFlightDnsQueries;
while(previous->next) {
if(previous->next == query)
break;
previous = previous->next;
}
assert(previous->next != NULL);
previous->next = query->next;
if(previous->next == NULL)
inFlightDnsQueriesLast = previous;
}
}
static void
insertQuery(DnsQueryPtr query)
{
if(inFlightDnsQueriesLast)
inFlightDnsQueriesLast->next = query;
else
inFlightDnsQueries = query;
inFlightDnsQueriesLast = query;
}
static DnsQueryPtr
findQuery(int id, AtomPtr name)
{
DnsQueryPtr query;
query = inFlightDnsQueries;
while(query) {
if(query->id == id && (name == NULL || query->name == name))
return query;
query = query->next;
}
return NULL;
}
static int
dnsTimeoutHandler(TimeEventHandlerPtr event)
{
DnsQueryPtr query = *(DnsQueryPtr*)event->data;
ObjectPtr object = query->object;
int rc;
query->timeout = MAX(10, query->timeout * 2);
if(query->timeout > dnsMaxTimeout) {
removeQuery(query);
abortObject(object, 501, internAtom("Timeout"));
goto fail;
} else {
query->timeout_handler =
scheduleTimeEvent(query->timeout, dnsTimeoutHandler,
sizeof(query), &query);
if(query->timeout_handler == NULL) {
do_log(L_ERROR, "Couldn't schedule DNS timeout handler.\n");
abortObject(object, 501,
internAtom("Couldn't schedule DNS timeout handler"));
goto fail;
}
rc = sendQuery(query);
if(rc < 0) {
do_log(L_ERROR, "Couldn't send DNS query.\n");
if(rc != -EWOULDBLOCK && rc != -EAGAIN && rc != -ENOBUFS) {
abortObject(object, 501,
internAtom("Couldn't send DNS query"));
goto fail;
}
/* else let it timeout */
}
return 1;
}
fail:
object->flags &= ~OBJECT_INPROGRESS;
if(query->inet4) releaseAtom(query->inet4);
if(query->inet6) releaseAtom(query->inet6);
free(query);
releaseNotifyObject(object);
return 1;
}
static int
establishDnsSocket()
{
int rc;
#ifdef HAVE_IPv6
int inet6 = (nameserverAddress.sa_family == AF_INET6);
int pf = inet6 ? PF_INET6 : PF_INET;
int sa_size =
inet6 ? sizeof(struct sockaddr_in6) : sizeof(struct sockaddr_in);
#else
int pf = PF_INET;
int sa_size = sizeof(struct sockaddr_in);
#endif
if(dnsSocket < 0) {
assert(!dnsSocketHandler);
dnsSocket = socket(pf, SOCK_DGRAM, 0);
if(dnsSocket < 0) {
do_log_error(L_ERROR, errno, "Couldn't create DNS socket");
return -errno;
}
rc = connect(dnsSocket, &nameserverAddress, sa_size);
if(rc < 0) {
close(dnsSocket);
dnsSocket = -1;
do_log_error(L_ERROR, errno, "Couldn't create DNS \"connection\"");
return -errno;
}
}
if(!dnsSocketHandler) {
dnsSocketHandler =
registerFdEvent(dnsSocket, POLLIN, dnsReplyHandler, 0, NULL);
if(dnsSocketHandler == NULL) {
do_log(L_ERROR, "Couldn't register DNS socket handler.\n");
close(dnsSocket);
dnsSocket = -1;
return -ENOMEM;
}
}
return 1;
}
static int
sendQuery(DnsQueryPtr query)
{
char buf[512];
int buflen;
int rc;
int af[2];
int i;
if(dnsSocket < 0)
return -1;
if(dnsQueryIPv6 <= 0) {
af[0] = 4; af[1] = 0;
} else if(dnsQueryIPv6 <= 2) {
af[0] = 4; af[1] = 6;
} else {
af[0] = 6; af[1] = 0;
}
for(i = 0; i < 2; i++) {
if(af[i] == 0)
continue;
if(af[i] == 4 && query->inet4)
continue;
else if(af[i] == 6 && query->inet6)
continue;
buflen = dnsBuildQuery(query->id, buf, 0, 512, query->name, af[i]);
if(buflen <= 0) {
do_log(L_ERROR, "Couldn't build DNS query.\n");
return buflen;
}
rc = send(dnsSocket, buf, buflen, 0);
if(rc < buflen) {
if(rc >= 0) {
do_log(L_ERROR, "Couldn't send DNS query: partial send");
return -EAGAIN;
} else {
do_log_error(L_ERROR, errno, "Couldn't send DNS query");
return -errno;
}
}
}
return 1;
}
static int
really_do_dns(AtomPtr name, ObjectPtr object)
{
int rc;
DnsQueryPtr query;
AtomPtr message = NULL;
int id;
AtomPtr a = NULL;
if(a == NULL) {
struct in_addr ina;
rc = inet_aton(name->string, &ina);
if(rc == 1) {
char s[1 + sizeof(HostAddressRec)];
memset(s, 0, sizeof(s));
s[0] = DNS_A;
s[1] = 4;
memcpy(s + 2, &ina, 4);
a = internAtomN(s, 1 + sizeof(HostAddressRec));
if(a == NULL) {
abortObject(object, 501,
internAtom("Couldn't allocate address"));
notifyObject(object);
errno = ENOMEM;
return -1;
}
}
}
#ifdef HAVE_IPv6
if(a == NULL)
a = rfc2732(name);
#endif
if(a) {
object->headers = a;
object->age = current_time.tv_sec;
object->expires = current_time.tv_sec + 240;
object->flags &= ~(OBJECT_INITIAL | OBJECT_INPROGRESS);
notifyObject(object);
return 0;
}
rc = establishDnsSocket();
if(rc < 0) {
do_log_error(L_ERROR, -rc, "Couldn't establish DNS socket.\n");
message = internAtomError(-rc, "Couldn't establish DNS socket");
goto fallback;
}
/* The id is used to speed up detecting replies to queries that
are no longer current -- see dnsReplyHandler. */
id = (idSeed++) & 0xFFFF;
query = malloc(sizeof(DnsQueryRec));
if(query == NULL) {
do_log(L_ERROR, "Couldn't allocate DNS query.\n");
message = internAtom("Couldn't allocate DNS query");
goto fallback;
}
query->id = id;
query->inet4 = NULL;
query->inet6 = NULL;
query->name = name;
query->time = current_time.tv_sec;
query->object = retainObject(object);
query->timeout = 4;
query->timeout_handler = NULL;
query->next = NULL;
query->timeout_handler =