summaryrefslogtreecommitdiffstats
path: root/avahi-compat-libdns_sd/dns_sd.h
blob: 66e494e40210666ab4076ac25bb81e200a208bc4 (plain)
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
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
/* -*- Mode: C; tab-width: 4 -*-
 *
 * Copyright (c) 2003-2004, Apple Computer, Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1.  Redistributions of source code must retain the above copyright notice,
 *     this list of conditions and the following disclaimer.
 * 2.  Redistributions in binary form must reproduce the above copyright notice,
 *     this list of conditions and the following disclaimer in the documentation
 *     and/or other materials provided with the distribution.
 * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of its
 *     contributors may be used to endorse or promote products derived from this
 *     software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef _DNS_SD_H
#define _DNS_SD_H

#ifdef  __cplusplus
    extern "C" {
#endif

/* standard calling convention under Win32 is __stdcall */
/* Note: When compiling Intel EFI (Extensible Firmware Interface) under MS Visual Studio, the */
/* _WIN32 symbol is defined by the compiler even though it's NOT compiling code for Windows32 */
#if defined(_WIN32) && !defined(EFI32) && !defined(EFI64)
#define DNSSD_API __stdcall
#else
#define DNSSD_API
#endif

/* stdint.h does not exist on FreeBSD 4.x; its types are defined in sys/types.h instead */
#if defined(__FreeBSD__) && (__FreeBSD__ < 5)
#include <sys/types.h>

/* Likewise, on Sun, standard integer types are in sys/types.h */
#elif defined(__sun__)
#include <sys/types.h>

/* EFI does not have stdint.h, or anything else equivalent */
#elif defined(EFI32) || defined(EFI64)
typedef UINT8       uint8_t;
typedef INT8        int8_t;
typedef UINT16      uint16_t;
typedef INT16       int16_t;
typedef UINT32      uint32_t;
typedef INT32       int32_t;

/* Windows has its own differences */
#elif defined(_WIN32)
#include <windows.h>
#define _UNUSED
#define bzero(a, b) memset(a, 0, b)
#ifndef _MSL_STDINT_H
typedef UINT8       uint8_t;
typedef INT8        int8_t;
typedef UINT16      uint16_t;
typedef INT16       int16_t;
typedef UINT32      uint32_t;
typedef INT32       int32_t;
#endif

/* All other Posix platforms use stdint.h */
#else
#include <stdint.h>
#endif

/* DNSServiceRef, DNSRecordRef
 *
 * Opaque internal data types.
 * Note: client is responsible for serializing access to these structures if
 * they are shared between concurrent threads.
 */

typedef struct _DNSServiceRef_t *DNSServiceRef;
typedef struct _DNSRecordRef_t *DNSRecordRef;

/* General flags used in functions defined below */
enum
    {
    kDNSServiceFlagsMoreComing          = 0x1,
    /* MoreComing indicates to a callback that at least one more result is
     * queued and will be delivered following immediately after this one.
     * Applications should not update their UI to display browse
     * results when the MoreComing flag is set, because this would
     * result in a great deal of ugly flickering on the screen.
     * Applications should instead wait until until MoreComing is not set,
     * and then update their UI.
     * When MoreComing is not set, that doesn't mean there will be no more
     * answers EVER, just that there are no more answers immediately
     * available right now at this instant. If more answers become available
     * in the future they will be delivered as usual.
     */

    kDNSServiceFlagsAdd                 = 0x2,
    kDNSServiceFlagsDefault             = 0x4,
    /* Flags for domain enumeration and browse/query reply callbacks.
     * "Default" applies only to enumeration and is only valid in
     * conjuction with "Add".  An enumeration callback with the "Add"
     * flag NOT set indicates a "Remove", i.e. the domain is no longer
     * valid.
     */

    kDNSServiceFlagsNoAutoRename        = 0x8,
    /* Flag for specifying renaming behavior on name conflict when registering
     * non-shared records. By default, name conflicts are automatically handled
     * by renaming the service.  NoAutoRename overrides this behavior - with this
     * flag set, name conflicts will result in a callback.  The NoAutorename flag
     * is only valid if a name is explicitly specified when registering a service
     * (i.e. the default name is not used.)
     */

    kDNSServiceFlagsShared              = 0x10,
    kDNSServiceFlagsUnique              = 0x20,
    /* Flag for registering individual records on a connected
     * DNSServiceRef.  Shared indicates that there may be multiple records
     * with this name on the network (e.g. PTR records).  Unique indicates that the
     * record's name is to be unique on the network (e.g. SRV records).
     */

    kDNSServiceFlagsBrowseDomains       = 0x40,
    kDNSServiceFlagsRegistrationDomains = 0x80,
    /* Flags for specifying domain enumeration type in DNSServiceEnumerateDomains.
     * BrowseDomains enumerates domains recommended for browsing, RegistrationDomains
     * enumerates domains recommended for registration.
     */

    kDNSServiceFlagsLongLivedQuery      = 0x100,
    /* Flag for creating a long-lived unicast query for the DNSServiceQueryRecord call. */

    kDNSServiceFlagsAllowRemoteQuery    = 0x200,
    /* Flag for creating a record for which we will answer remote queries
     * (queries from hosts more than one hop away; hosts not directly connected to the local link).
     */

    kDNSServiceFlagsForceMulticast      = 0x400,
    /* Flag for signifying that a query or registration should be performed exclusively via multicast DNS,
     * even for a name in a domain (e.g. foo.apple.com.) that would normally imply unicast DNS.
     */

    kDNSServiceFlagsReturnCNAME         = 0x800
    /* Flag for returning CNAME records in the DNSServiceQueryRecord call. CNAME records are
     * normally followed without indicating to the client that there was a CNAME record.
     */
    };

/*
 * The values for DNS Classes and Types are listed in RFC 1035, and are available
 * on every OS in its DNS header file. Unfortunately every OS does not have the
 * same header file containing DNS Class and Type constants, and the names of
 * the constants are not consistent. For example, BIND 8 uses "T_A",
 * BIND 9 uses "ns_t_a", Windows uses "DNS_TYPE_A", etc.
 * For this reason, these constants are also listed here, so that code using
 * the DNS-SD programming APIs can use these constants, so that the same code
 * can compile on all our supported platforms.
 */

enum
    {
    kDNSServiceClass_IN       = 1       /* Internet */
    };

enum
    {
    kDNSServiceType_A         = 1,      /* Host address. */
    kDNSServiceType_NS        = 2,      /* Authoritative server. */
    kDNSServiceType_MD        = 3,      /* Mail destination. */
    kDNSServiceType_MF        = 4,      /* Mail forwarder. */
    kDNSServiceType_CNAME     = 5,      /* Canonical name. */
    kDNSServiceType_SOA       = 6,      /* Start of authority zone. */
    kDNSServiceType_MB        = 7,      /* Mailbox domain name. */
    kDNSServiceType_MG        = 8,      /* Mail group member. */
    kDNSServiceType_MR        = 9,      /* Mail rename name. */
    kDNSServiceType_NULL      = 10,     /* Null resource record. */
    kDNSServiceType_WKS       = 11,     /* Well known service. */
    kDNSServiceType_PTR       = 12,     /* Domain name pointer. */
    kDNSServiceType_HINFO     = 13,     /* Host information. */
    kDNSServiceType_MINFO     = 14,     /* Mailbox information. */
    kDNSServiceType_MX        = 15,     /* Mail routing information. */
    kDNSServiceType_TXT       = 16,     /* One or more text strings. */
    kDNSServiceType_RP        = 17,     /* Responsible person. */
    kDNSServiceType_AFSDB     = 18,     /* AFS cell database. */
    kDNSServiceType_X25       = 19,     /* X_25 calling address. */
    kDNSServiceType_ISDN      = 20,     /* ISDN calling address. */
    kDNSServiceType_RT        = 21,     /* Router. */
    kDNSServiceType_NSAP      = 22,     /* NSAP address. */
    kDNSServiceType_NSAP_PTR  = 23,     /* Reverse NSAP lookup (deprecated). */
    kDNSServiceType_SIG       = 24,     /* Security signature. */
    kDNSServiceType_KEY       = 25,     /* Security key. */
    kDNSServiceType_PX        = 26,     /* X.400 mail mapping. */
    kDNSServiceType_GPOS      = 27,     /* Geographical position (withdrawn). */
    kDNSServiceType_AAAA      = 28,     /* IPv6 Address. */
    kDNSServiceType_LOC       = 29,     /* Location Information. */
    kDNSServiceType_NXT       = 30,     /* Next domain (security). */
    kDNSServiceType_EID       = 31,     /* Endpoint identifier. */
    kDNSServiceType_NIMLOC    = 32,     /* Nimrod Locator. */
    kDNSServiceType_SRV       = 33,     /* Server Selection. */
    kDNSServiceType_ATMA      = 34,     /* ATM Address */
    kDNSServiceType_NAPTR     = 35,     /* Naming Authority PoinTeR */
    kDNSServiceType_KX        = 36,     /* Key Exchange */
    kDNSServiceType_CERT      = 37,     /* Certification record */
    kDNSServiceType_A6        = 38,     /* IPv6 Address (deprecated) */
    kDNSServiceType_DNAME     = 39,     /* Non-terminal DNAME (for IPv6) */
    kDNSServiceType_SINK      = 40,     /* Kitchen sink (experimentatl) */
    kDNSServiceType_OPT       = 41,     /* EDNS0 option (meta-RR) */
    kDNSServiceType_TKEY      = 249,    /* Transaction key */
    kDNSServiceType_TSIG      = 250,    /* Transaction signature. */
    kDNSServiceType_IXFR      = 251,    /* Incremental zone transfer. */
    kDNSServiceType_AXFR      = 252,    /* Transfer zone of authority. */
    kDNSServiceType_MAILB     = 253,    /* Transfer mailbox records. */
    kDNSServiceType_MAILA     = 254,    /* Transfer mail agent records. */
    kDNSServiceType_ANY       = 255     /* Wildcard match. */
    };


/* possible error code values */
enum
    {
    kDNSServiceErr_NoError             = 0,
    kDNSServiceErr_Unknown             = -65537,       /* 0xFFFE FFFF */
    kDNSServiceErr_NoSuchName          = -65538,
    kDNSServiceErr_NoMemory            = -65539,
    kDNSServiceErr_BadParam            = -65540,
    kDNSServiceErr_BadReference        = -65541,
    kDNSServiceErr_BadState            = -65542,
    kDNSServiceErr_BadFlags            = -65543,
    kDNSServiceErr_Unsupported         = -65544,
    kDNSServiceErr_NotInitialized      = -65545,
    kDNSServiceErr_AlreadyRegistered   = -65547,
    kDNSServiceErr_NameConflict        = -65548,
    kDNSServiceErr_Invalid             = -65549,
    kDNSServiceErr_Firewall            = -65550,
    kDNSServiceErr_Incompatible        = -65551,        /* client library incompatible with daemon */
    kDNSServiceErr_BadInterfaceIndex   = -65552,
    kDNSServiceErr_Refused             = -65553,
    kDNSServiceErr_NoSuchRecord        = -65554,
    kDNSServiceErr_NoAuth              = -65555,
    kDNSServiceErr_NoSuchKey           = -65556,
    kDNSServiceErr_NATTraversal        = -65557,
    kDNSServiceErr_DoubleNAT           = -65558,
    kDNSServiceErr_BadTime             = -65559
    /* mDNS Error codes are in the range
     * FFFE FF00 (-65792) to FFFE FFFF (-65537) */
    };


/* Maximum length, in bytes, of a service name represented as a */
/* literal C-String, including the terminating NULL at the end. */

#define kDNSServiceMaxServiceName 64

/* Maximum length, in bytes, of a domain name represented as an *escaped* C-String */
/* including the final trailing dot, and the C-String terminating NULL at the end. */

#define kDNSServiceMaxDomainName 1005

/*
 * Notes on DNS Name Escaping
 *   -- or --
 * "Why is kDNSServiceMaxDomainName 1005, when the maximum legal domain name is 255 bytes?"
 *
 * All strings used in DNS-SD are UTF-8 strings.
 * With few exceptions, most are also escaped using standard DNS escaping rules:
 *
 *   '\\' represents a single literal '\' in the name
 *   '\.' represents a single literal '.' in the name
 *   '\ddd', where ddd is a three-digit decimal value from 000 to 255,
 *        represents a single literal byte with that value.
 *   A bare unescaped '.' is a label separator, marking a boundary between domain and subdomain.
 *
 * The exceptions, that do not use escaping, are the routines where the full
 * DNS name of a resource is broken, for convenience, into servicename/regtype/domain.
 * In these routines, the "servicename" is NOT escaped. It does not need to be, since
 * it is, by definition, just a single literal string. Any characters in that string
 * represent exactly what they are. The "regtype" portion is, technically speaking,
 * escaped, but since legal regtypes are only allowed to contain letters, digits,
 * and hyphens, there is nothing to escape, so the issue is moot. The "domain"
 * portion is also escaped, though most domains in use on the public Internet
 * today, like regtypes, don't contain any characters that need to be escaped.
 * As DNS-SD becomes more popular, rich-text domains for service discovery will
 * become common, so software should be written to cope with domains with escaping.
 *
 * The servicename may be up to 63 bytes of UTF-8 text (not counting the C-String
 * terminating NULL at the end). The regtype is of the form _service._tcp or
 * _service._udp, where the "service" part is 1-14 characters, which may be
 * letters, digits, or hyphens. The domain part of the three-part name may be
 * any legal domain, providing that the resulting servicename+regtype+domain
 * name does not exceed 255 bytes.
 *
 * For most software, these issues are transparent. When browsing, the discovered
 * servicenames should simply be displayed as-is. When resolving, the discovered
 * servicename/regtype/domain are simply passed unchanged to DNSServiceResolve().
 * When a DNSServiceResolve() succeeds, the returned fullname is already in
 * the correct format to pass to standard system DNS APIs such as res_query().
 * For converting from servicename/regtype/domain to a single properly-escaped
 * full DNS name, the helper function DNSServiceConstructFullName() is provided.
 *
 * The following (highly contrived) example illustrates the escaping process.
 * Suppose you have an service called "Dr. Smith\Dr. Johnson", of type "_ftp._tcp"
 * in subdomain "4th. Floor" of subdomain "Building 2" of domain "apple.com."
 * The full (escaped) DNS name of this service's SRV record would be:
 * Dr\.\032Smith\\Dr\.\032Johnson._ftp._tcp.4th\.\032Floor.Building\0322.apple.com.
 */


/*
 * Constants for specifying an interface index
 *
 * Specific interface indexes are identified via a 32-bit unsigned integer returned
 * by the if_nametoindex() family of calls.
 *
 * If the client passes 0 for interface index, that means "do the right thing",
 * which (at present) means, "if the name is in an mDNS local multicast domain
 * (e.g. 'local.', '254.169.in-addr.arpa.', '{8,9,A,B}.E.F.ip6.arpa.') then multicast
 * on all applicable interfaces, otherwise send via unicast to the appropriate
 * DNS server." Normally, most clients will use 0 for interface index to
 * automatically get the default sensible behaviour.
 *
 * If the client passes a positive interface index, then for multicast names that
 * indicates to do the operation only on that one interface. For unicast names the
 * interface index is ignored unless kDNSServiceFlagsForceMulticast is also set.
 *
 * If the client passes kDNSServiceInterfaceIndexLocalOnly when registering
 * a service, then that service will be found *only* by other local clients
 * on the same machine that are browsing using kDNSServiceInterfaceIndexLocalOnly
 * or kDNSServiceInterfaceIndexAny.
 * If a client has a 'private' service, accessible only to other processes
 * running on the same machine, this allows the client to advertise that service
 * in a way such that it does not inadvertently appear in service lists on
 * all the other machines on the network.
 *
 * If the client passes kDNSServiceInterfaceIndexLocalOnly when browsing
 * then it will find *all* records registered on that same local machine.
 * Clients explicitly wishing to discover *only* LocalOnly services can
 * accomplish this by inspecting the interfaceIndex of each service reported
 * to their DNSServiceBrowseReply() callback function, and discarding those
 * where the interface index is not kDNSServiceInterfaceIndexLocalOnly.
 */

#define kDNSServiceInterfaceIndexAny 0
#define kDNSServiceInterfaceIndexLocalOnly ( (uint32_t) -1 )


typedef uint32_t DNSServiceFlags;
typedef int32_t DNSServiceErrorType;


/*********************************************************************************************
 *
 * Unix Domain Socket access, DNSServiceRef deallocation, and data processing functions
 *
 *********************************************************************************************/


/* DNSServiceRefSockFD()
 *
 * Access underlying Unix domain socket for an initialized DNSServiceRef.
 * The DNS Service Discovery implmementation uses this socket to communicate between
 * the client and the mDNSResponder daemon.  The application MUST NOT directly read from
 * or write to this socket.  Access to the socket is provided so that it can be used as a
 * run loop source, or in a select() loop: when data is available for reading on the socket,
 * DNSServiceProcessResult() should be called, which will extract the daemon's reply from
 * the socket, and pass it to the appropriate application callback.  By using a run loop or
 * select(), results from the daemon can be processed asynchronously.  Without using these
 * constructs, DNSServiceProcessResult() will block until the response from the daemon arrives.
 * The client is responsible for ensuring that the data on the socket is processed in a timely
 * fashion - the daemon may terminate its connection with a client that does not clear its
 * socket buffer.
 *
 * sdRef:            A DNSServiceRef initialized by any of the DNSService calls.
 *
 * return value:    The DNSServiceRef's underlying socket descriptor, or -1 on
 *                  error.
 */

int DNSSD_API DNSServiceRefSockFD(DNSServiceRef sdRef);


/* DNSServiceProcessResult()
 *
 * Read a reply from the daemon, calling the appropriate application callback.  This call will
 * block until the daemon's response is received.  Use DNSServiceRefSockFD() in
 * conjunction with a run loop or select() to determine the presence of a response from the
 * server before calling this function to process the reply without blocking.  Call this function
 * at any point if it is acceptable to block until the daemon's response arrives.  Note that the
 * client is responsible for ensuring that DNSServiceProcessResult() is called whenever there is
 * a reply from the daemon - the daemon may terminate its connection with a client that does not
 * process the daemon's responses.
 *
 * sdRef:           A DNSServiceRef initialized by any of the DNSService calls
 *                  that take a callback parameter.
 *
 * return value:    Returns kDNSServiceErr_NoError on success, otherwise returns
 *                  an error code indicating the specific failure that occurred.
 */

DNSServiceErrorType DNSSD_API DNSServiceProcessResult(DNSServiceRef sdRef);


/* DNSServiceRefDeallocate()
 *
 * Terminate a connection with the daemon and free memory associated with the DNSServiceRef.
 * Any services or records registered with this DNSServiceRef will be deregistered. Any
 * Browse, Resolve, or Query operations called with this reference will be terminated.
 *
 * Note: If the reference's underlying socket is used in a run loop or select() call, it should
 * be removed BEFORE DNSServiceRefDeallocate() is called, as this function closes the reference's
 * socket.
 *
 * Note: If the reference was initialized with DNSServiceCreateConnection(), any DNSRecordRefs
 * created via this reference will be invalidated by this call - the resource records are
 * deregistered, and their DNSRecordRefs may not be used in subsequent functions.  Similarly,
 * if the reference was initialized with DNSServiceRegister, and an extra resource record was
 * added to the service via DNSServiceAddRecord(), the DNSRecordRef created by the Add() call
 * is invalidated when this function is called - the DNSRecordRef may not be used in subsequent
 * functions.
 *
 * Note: This call is to be used only with the DNSServiceRef defined by this API.  It is
 * not compatible with dns_service_discovery_ref objects defined in the legacy Mach-based
 * DNSServiceDiscovery.h API.
 *
 * sdRef:           A DNSServiceRef initialized by any of the DNSService calls.
 *
 */

void DNSSD_API DNSServiceRefDeallocate(DNSServiceRef sdRef);


/*********************************************************************************************
 *
 * Domain Enumeration
 *
 *********************************************************************************************/

/* DNSServiceEnumerateDomains()
 *
 * Asynchronously enumerate domains available for browsing and registration.
 *
 * The enumeration MUST be cancelled via DNSServiceRefDeallocate() when no more domains
 * are to be found.
 *
 * Note that the names returned are (like all of DNS-SD) UTF-8 strings,
 * and are escaped using standard DNS escaping rules.
 * (See "Notes on DNS Name Escaping" earlier in this file for more details.)
 * A graphical browser displaying a hierarchical tree-structured view should cut
 * the names at the bare dots to yield individual labels, then de-escape each
 * label according to the escaping rules, and then display the resulting UTF-8 text.
 *
 * DNSServiceDomainEnumReply Callback Parameters:
 *
 * sdRef:           The DNSServiceRef initialized by DNSServiceEnumerateDomains().
 *
 * flags:           Possible values are:
 *                  kDNSServiceFlagsMoreComing
 *                  kDNSServiceFlagsAdd
 *                  kDNSServiceFlagsDefault
 *
 * interfaceIndex:  Specifies the interface on which the domain exists.  (The index for a given
 *                  interface is determined via the if_nametoindex() family of calls.)
 *
 * errorCode:       Will be kDNSServiceErr_NoError (0) on success, otherwise indicates
 *                  the failure that occurred (other parameters are undefined if errorCode is nonzero).
 *
 * replyDomain:     The name of the domain.
 *
 * context:         The context pointer passed to DNSServiceEnumerateDomains.
 *
 */

typedef void (DNSSD_API *DNSServiceDomainEnumReply)
    (
    DNSServiceRef                       sdRef,
    DNSServiceFlags                     flags,
    uint32_t                            interfaceIndex,
    DNSServiceErrorType                 errorCode,
    const char                          *replyDomain,
    void                                *context
    );


/* DNSServiceEnumerateDomains() Parameters:
 *
 *
 * sdRef:           A pointer to an uninitialized DNSServiceRef. If the call succeeds
 *                  then it initializes the DNSServiceRef, returns kDNSServiceErr_NoError,
 *                  and the enumeration operation will run indefinitely until the client
 *                  terminates it by passing this DNSServiceRef to DNSServiceRefDeallocate().
 *
 * flags:           Possible values are:
 *                  kDNSServiceFlagsBrowseDomains to enumerate domains recommended for browsing.
 *                  kDNSServiceFlagsRegistrationDomains to enumerate domains recommended
 *                  for registration.
 *
 * interfaceIndex:  If non-zero, specifies the interface on which to look for domains.
 *                  (the index for a given interface is determined via the if_nametoindex()
 *                  family of calls.)  Most applications will pass 0 to enumerate domains on
 *                  all interfaces. See "Constants for specifying an interface index" for more details.
 *
 * callBack:        The function to be called when a domain is found or the call asynchronously
 *                  fails.
 *
 * context:         An application context pointer which is passed to the callback function
 *                  (may be NULL).
 *
 * return value:    Returns kDNSServiceErr_NoError on succeses (any subsequent, asynchronous
 *                  errors are delivered to the callback), otherwise returns an error code indicating
 *                  the error that occurred (the callback is not invoked and the DNSServiceRef
 *                  is not initialized.)
 */

DNSServiceErrorType DNSSD_API DNSServiceEnumerateDomains
    (
    DNSServiceRef                       *sdRef,
    DNSServiceFlags                     flags,
    uint32_t                            interfaceIndex,
    DNSServiceDomainEnumReply           callBack,
    void                                *context  /* may be NULL */
    );


/*********************************************************************************************
 *
 *  Service Registration
 *
 *********************************************************************************************/

/* Register a service that is discovered via Browse() and Resolve() calls.
 *
 *
 * DNSServiceRegisterReply() Callback Parameters:
 *
 * sdRef:           The DNSServiceRef initialized by DNSServiceRegister().
 *
 * flags:           Currently unused, reserved for future use.
 *
 * errorCode:       Will be kDNSServiceErr_NoError on success, otherwise will
 *                  indicate the failure that occurred (including name conflicts,
 *                  if the kDNSServiceFlagsNoAutoRename flag was used when registering.)
 *                  Other parameters are undefined if errorCode is nonzero.
 *
 * name:            The service name registered (if the application did not specify a name in
 *                  DNSServiceRegister(), this indicates what name was automatically chosen).
 *
 * regtype:         The type of service registered, as it was passed to the callout.
 *
 * domain:          The domain on which the service was registered (if the application did not
 *                  specify a domain in DNSServiceRegister(), this indicates the default domain
 *                  on which the service was registered).
 *
 * context:         The context pointer that was passed to the callout.
 *
 */

typedef void (DNSSD_API *DNSServiceRegisterReply)
    (
    DNSServiceRef                       sdRef,
    DNSServiceFlags                     flags,
    DNSServiceErrorType                 errorCode,
    const char                          *name,
    const char                          *regtype,
    const char                          *domain,
    void                                *context
    );


/* DNSServiceRegister()  Parameters:
 *
 * sdRef:           A pointer to an uninitialized DNSServiceRef. If the call succeeds
 *                  then it initializes the DNSServiceRef, returns kDNSServiceErr_NoError,
 *                  and the registration will remain active indefinitely until the client
 *                  terminates it by passing this DNSServiceRef to DNSServiceRefDeallocate().
 *
 * interfaceIndex:  If non-zero, specifies the interface on which to register the service
 *                  (the index for a given interface is determined via the if_nametoindex()
 *                  family of calls.)  Most applications will pass 0 to register on all
 *                  available interfaces. See "Constants for specifying an interface index" for more details.
 *
 * flags:           Indicates the renaming behavior on name conflict (most applications
 *                  will pass 0).  See flag definitions above for details.
 *
 * name:            If non-NULL, specifies the service name to be registered.
 *                  Most applications will not specify a name, in which case the computer
 *                  name is used (this name is communicated to the client via the callback).
 *                  If a name is specified, it must be 1-63 bytes of UTF-8 text.
 *                  If the name is longer than 63 bytes it will be automatically truncated
 *                  to a legal length, unless the NoAutoRename flag is set,
 *                  in which case kDNSServiceErr_BadParam will be returned.
 *
 * regtype:         The service type followed by the protocol, separated by a dot
 *                  (e.g. "_ftp._tcp"). The service type must be an underscore, followed
 *                  by 1-14 characters, which may be letters, digits, or hyphens.
 *                  The transport protocol must be "_tcp" or "_udp". New service types
 *                  should be registered at <http://www.dns-sd.org/ServiceTypes.html>.
 *
 * domain:          If non-NULL, specifies the domain on which to advertise the service.
 *                  Most applications will not specify a domain, instead automatically
 *                  registering in the default domain(s).
 *
 * host:            If non-NULL, specifies the SRV target host name.  Most applications
 *                  will not specify a host, instead automatically using the machine's
 *                  default host name(s).  Note that specifying a non-NULL host does NOT
 *                  create an address record for that host - the application is responsible
 *                  for ensuring that the appropriate address record exists, or creating it
 *                  via DNSServiceRegisterRecord().
 *
 * port:            The port, in network byte order, on which the service accepts connections.
 *                  Pass 0 for a "placeholder" service (i.e. a service that will not be discovered
 *                  by browsing, but will cause a name conflict if another client tries to
 *                  register that same name).  Most clients will not use placeholder services.
 *
 * txtLen:          The length of the txtRecord, in bytes.  Must be zero if the txtRecord is NULL.
 *
 * txtRecord:       The TXT record rdata. A non-NULL txtRecord MUST be a properly formatted DNS
 *                  TXT record, i.e. <length byte> <data> <length byte> <data> ...
 *                  Passing NULL for the txtRecord is allowed as a synonym for txtLen=1, txtRecord="",
 *                  i.e. it creates a TXT record of length one containing a single empty string.
 *                  RFC 1035 doesn't allow a TXT record to contain *zero* strings, so a single empty
 *                  string is the smallest legal DNS TXT record.
 *                  As with the other parameters, the DNSServiceRegister call copies the txtRecord
 *                  data; e.g. if you allocated the storage for the txtRecord parameter with malloc()
 *                  then you can safely free that memory right after the DNSServiceRegister call returns.
 *
 * callBack:        The function to be called when the registration completes or asynchronously
 *                  fails.  The client MAY pass NULL for the callback -  The client will NOT be notified
 *                  of the default values picked on its behalf, and the client will NOT be notified of any
 *                  asynchronous errors (e.g. out of memory errors, etc.) that may prevent the registration
 *                  of the service.  The client may NOT pass the NoAutoRename flag if the callback is NULL.
 *                  The client may still deregister the service at any time via DNSServiceRefDeallocate().
 *
 * context:         An application context pointer which is passed to the callback function
 *                  (may be NULL).
 *
 * return value:    Returns kDNSServiceErr_NoError on succeses (any subsequent, asynchronous
 *                  errors are delivered to the callback), otherwise returns an error code indicating
 *                  the error that occurred (the callback is never invoked and the DNSServiceRef
 *                  is not initialized.)
 */

DNSServiceErrorType DNSSD_API DNSServiceRegister
    (
    DNSServiceRef                       *sdRef,
    DNSServiceFlags                     flags,
    uint32_t                            interfaceIndex,
    const char                          *name,         /* may be NULL */
    const char                          *regtype,
    const char                          *domain,       /* may be NULL */
    const char                          *host,         /* may be NULL */
    uint16_t                            port,
    uint16_t                            txtLen,
    const void                          *txtRecord,    /* may be NULL */
    DNSServiceRegisterReply             callBack,      /* may be NULL */
    void                                *context       /* may be NULL */
    );


/* DNSServiceAddRecord()
 *
 * Add a record to a registered service.  The name of the record will be the same as the
 * registered service's name.
 * The record can later be updated or deregistered by passing the RecordRef initialized
 * by this function to DNSServiceUpdateRecord() or DNSServiceRemoveRecord().
 *
 * Note that the DNSServiceAddRecord/UpdateRecord/RemoveRecord are *NOT* thread-safe
 * with respect to a single DNSServiceRef. If you plan to have multiple threads
 * in your program simultaneously add, update, or remove records from the same
 * DNSServiceRef, then it's the caller's responsibility to use a mutext lock
 * or take similar appropriate precautions to serialize those calls.
 *
 *
 * Parameters;
 *
 * sdRef:           A DNSServiceRef initialized by DNSServiceRegister().
 *
 * RecordRef:       A pointer to an uninitialized DNSRecordRef.  Upon succesfull completion of this
 *                  call, this ref may be passed to DNSServiceUpdateRecord() or DNSServiceRemoveRecord().
 *                  If the above DNSServiceRef is passed to DNSServiceRefDeallocate(), RecordRef is also
 *                  invalidated and may not be used further.
 *
 * flags:           Currently ignored, reserved for future use.
 *
 * rrtype:          The type of the record (e.g. kDNSServiceType_TXT, kDNSServiceType_SRV, etc)
 *
 * rdlen:           The length, in bytes, of the rdata.
 *
 * rdata:           The raw rdata to be contained in the added resource record.
 *
 * ttl:             The time to live of the resource record, in seconds.  Pass 0 to use a default value.
 *
 * return value:    Returns kDNSServiceErr_NoError on success, otherwise returns an
 *                  error code indicating the error that occurred (the RecordRef is not initialized).
 */

DNSServiceErrorType DNSSD_API DNSServiceAddRecord
    (
    DNSServiceRef                       sdRef,
    DNSRecordRef                        *RecordRef,
    DNSServiceFlags                     flags,
    uint16_t                            rrtype,
    uint16_t                            rdlen,
    const void                          *rdata,
    uint32_t                            ttl
    );


/* DNSServiceUpdateRecord
 *
 * Update a registered resource record.  The record must either be:
 *   - The primary txt record of a service registered via DNSServiceRegister()
 *   - A record added to a registered service via DNSServiceAddRecord()
 *   - An individual record registered by DNSServiceRegisterRecord()
 *
 *
 * Parameters:
 *
 * sdRef:           A DNSServiceRef that was initialized by DNSServiceRegister()
 *                  or DNSServiceCreateConnection().
 *
 * RecordRef:       A DNSRecordRef initialized by DNSServiceAddRecord, or NULL to update the
 *                  service's primary txt record.
 *
 * flags:           Currently ignored, reserved for future use.
 *
 * rdlen:           The length, in bytes, of the new rdata.
 *
 * rdata:           The new rdata to be contained in the updated resource record.
 *
 * ttl:             The time to live of the updated resource record, in seconds.
 *
 * return value:    Returns kDNSServiceErr_NoError on success, otherwise returns an
 *                  error code indicating the error that occurred.
 */

DNSServiceErrorType DNSSD_API DNSServiceUpdateRecord
    (
    DNSServiceRef                       sdRef,
    DNSRecordRef                        RecordRef,     /* may be NULL */
    DNSServiceFlags                     flags,
    uint16_t                            rdlen,
    const void                          *rdata,
    uint32_t                            ttl
    );


/* DNSServiceRemoveRecord
 *
 * Remove a record previously added to a service record set via DNSServiceAddRecord(), or deregister
 * an record registered individually via DNSServiceRegisterRecord().
 *
 * Parameters:
 *
 * sdRef:           A DNSServiceRef initialized by DNSServiceRegister() (if the
 *                  record being removed was registered via DNSServiceAddRecord()) or by
 *                  DNSServiceCreateConnection() (if the record being removed was registered via
 *                  DNSServiceRegisterRecord()).
 *
 * recordRef:       A DNSRecordRef initialized by a successful call to DNSServiceAddRecord()
 *                  or DNSServiceRegisterRecord().
 *
 * flags:           Currently ignored, reserved for future use.
 *
 * return value:    Returns kDNSServiceErr_NoError on success, otherwise returns an
 *                  error code indicating the error that occurred.
 */

DNSServiceErrorType DNSSD_API DNSServiceRemoveRecord
    (
    DNSServiceRef                 sdRef,
    DNSRecordRef                  RecordRef,
    DNSServiceFlags               flags
    );


/*********************************************************************************************
 *
 *  Service Discovery
 *
 *********************************************************************************************/

/* Browse for instances of a service.
 *
 *
 * DNSServiceBrowseReply() Parameters:
 *
 * sdRef:           The DNSServiceRef initialized by DNSServiceBrowse().
 *
 * flags:           Possible values are kDNSServiceFlagsMoreComing and kDNSServiceFlagsAdd.
 *                  See flag definitions for details.
 *
 * interfaceIndex:  The interface on which the service is advertised.  This index should
 *                  be passed to DNSServiceResolve() when resolving the service.
 *
 * errorCode:       Will be kDNSServiceErr_NoError (0) on success, otherwise will
 *                  indicate the failure that occurred.  Other parameters are undefined if
 *                  the errorCode is nonzero.
 *
 * serviceName:     The discovered service name. This name should be displayed to the user,
 *                  and stored for subsequent use in the DNSServiceResolve() call.
 *
 * regtype:         The service type, which is usually (but not always) the same as was passed
 *                  to DNSServiceBrowse(). One case where the discovered service type may
 *                  not be the same as the requested service type is when using subtypes:
 *                  The client may want to browse for only those ftp servers that allow
 *                  anonymous connections. The client will pass the string "_ftp._tcp,_anon"
 *                  to DNSServiceBrowse(), but the type of the service that's discovered
 *                  is simply "_ftp._tcp". The regtype for each discovered service instance
 *                  should be stored along with the name, so that it can be passed to
 *                  DNSServiceResolve() when the service is later resolved.
 *
 * domain:          The domain of the discovered service instance. This may or may not be the
 *                  same as the domain that was passed to DNSServiceBrowse(). The domain for each
 *                  discovered service instance should be stored along with the name, so that
 *                  it can be passed to DNSServiceResolve() when the service is later resolved.
 *
 * context:         The context pointer that was passed to the callout.
 *
 */

typedef void (DNSSD_API *DNSServiceBrowseReply)
    (
    DNSServiceRef                       sdRef,
    DNSServiceFlags                     flags,
    uint32_t                            interfaceIndex,
    DNSServiceErrorType                 errorCode,
    const char                          *serviceName,
    const char                          *regtype,
    const char                          *replyDomain,
    void                                *context
    );


/* DNSServiceBrowse() Parameters:
 *
 * sdRef:           A pointer to an uninitialized DNSServiceRef. If the call succeeds
 *                  then it initializes the DNSServiceRef, returns kDNSServiceErr_NoError,
 *                  and the browse operation will run indefinitely until the client
 *                  terminates it by passing this DNSServiceRef to DNSServiceRefDeallocate().
 *
 * flags:           Currently ignored, reserved for future use.
 *
 * interfaceIndex:  If non-zero, specifies the interface on which to browse for services
 *                  (the index for a given interface is determined via the if_nametoindex()
 *                  family of calls.)  Most applications will pass 0 to browse on all available
 *                  interfaces. See "Constants for specifying an interface index" for more details.
 *
 * regtype:         The service type being browsed for followed by the protocol, separated by a
 *                  dot (e.g. "_ftp._tcp").  The transport protocol must be "_tcp" or "_udp".
 *
 * domain:          If non-NULL, specifies the domain on which to browse for services.
 *                  Most applications will not specify a domain, instead browsing on the
 *                  default domain(s).
 *
 * callBack:        The function to be called when an instance of the service being browsed for
 *                  is found, or if the call asynchronously fails.
 *
 * context:         An application context pointer which is passed to the callback function
 *                  (may be NULL).
 *
 * return value:    Returns kDNSServiceErr_NoError on succeses (any subsequent, asynchronous
 *                  errors are delivered to the callback), otherwise returns an error code indicating
 *                  the error that occurred (the callback is not invoked and the DNSServiceRef
 *                  is not initialized.)
 */

DNSServiceErrorType DNSSD_API DNSServiceBrowse
    (
    DNSServiceRef                       *sdRef,
    DNSServiceFlags                     flags,
    uint32_t                            interfaceIndex,
    const char                          *regtype,
    const char                          *domain,    /* may be NULL */
    DNSServiceBrowseReply               callBack,
    void                                *context    /* may be NULL */
    );


/* DNSServiceResolve()
 *
 * Resolve a service name discovered via DNSServiceBrowse() to a target host name, port number, and
 * txt record.
 *
 * Note: Applications should NOT use DNSServiceResolve() solely for txt record monitoring - use
 * DNSServiceQueryRecord() instead, as it is more efficient for this task.
 *
 * Note: When the desired results have been returned, the client MUST terminate the resolve by calling
 * DNSServiceRefDeallocate().
 *
 * Note: DNSServiceResolve() behaves correctly for typical services that have a single SRV record
 * and a single TXT record. To resolve non-standard services with multiple SRV or TXT records,
 * DNSServiceQueryRecord() should be used.
 *
 * DNSServiceResolveReply Callback Parameters:
 *
 * sdRef:           The DNSServiceRef initialized by DNSServiceResolve().
 *
 * flags:           Currently unused, reserved for future use.
 *
 * interfaceIndex:  The interface on which the service was resolved.
 *
 * errorCode:       Will be kDNSServiceErr_NoError (0) on success, otherwise will
 *                  indicate the failure that occurred.  Other parameters are undefined if
 *                  the errorCode is nonzero.
 *
 * fullname:        The full service domain name, in the form <servicename>.<protocol>.<domain>.
 *                  (This name is escaped following standard DNS rules, making it suitable for
 *                  passing to standard system DNS APIs such as res_query(), or to the
 *                  special-purpose functions included in this API that take fullname parameters.
 *                  See "Notes on DNS Name Escaping" earlier in this file for more details.)
 *
 * hosttarget:      The target hostname of the machine providing the service.  This name can
 *                  be passed to functions like gethostbyname() to identify the host's IP address.
 *
 * port:            The port, in network byte order, on which connections are accepted for this service.
 *
 * txtLen:          The length of the txt record, in bytes.
 *
 * txtRecord:       The service's primary txt record, in standard txt record format.
 *
 * context:         The context pointer that was passed to the callout.
 *
 * NOTE: In earlier versions of this header file, the txtRecord parameter was declared "const char *"
 * This is incorrect, since it contains length bytes which are values in the range 0 to 255, not -128 to +127.
 * Depending on your compiler settings, this change may cause signed/unsigned mismatch warnings.
 * These should be fixed by updating your own callback function definition to match the corrected
 * function signature using "const unsigned char *txtRecord". Making this change may also fix inadvertent
 * bugs in your callback function, where it could have incorrectly interpreted a length byte with value 250
 * as being -6 instead, with various bad consequences ranging from incorrect operation to software crashes.
 * If you need to maintain portable code that will compile cleanly with both the old and new versions of
 * this header file, you should update your callback function definition to use the correct unsigned value,
 * and then in the place where you pass your callback function to DNSServiceResolve(), use a cast to eliminate
 * the compiler warning, e.g.:
 *   DNSServiceResolve(sd, flags, index, name, regtype, domain, (DNSServiceResolveReply)MyCallback, context);
 * This will ensure that your code compiles cleanly without warnings (and more importantly, works correctly)
 * with both the old header and with the new corrected version.
 *
 */

typedef void (DNSSD_API *DNSServiceResolveReply)
    (
    DNSServiceRef                       sdRef,
    DNSServiceFlags                     flags,
    uint32_t                            interfaceIndex,
    DNSServiceErrorType                 errorCode,
    const char                          *fullname,
    const char                          *hosttarget,
    uint16_t                            port,
    uint16_t                            txtLen,
    const unsigned char                 *txtRecord,
    void                                *context
    );


/* DNSServiceResolve() Parameters
 *
 * sdRef:           A pointer to an uninitialized DNSServiceRef. If the call succeeds
 *                  then it initializes the DNSServiceRef, returns kDNSServiceErr_NoError,
 *                  and the resolve operation will run indefinitely until the client
 *                  terminates it by passing this DNSServiceRef to DNSServiceRefDeallocate().
 *
 * flags:           Currently ignored, reserved for future use.
 *
 * interfaceIndex:  The interface on which to resolve the service. If this resolve call is
 *                  as a result of a currently active DNSServiceBrowse() operation, then the
 *                  interfaceIndex should be the index reported in the DNSServiceBrowseReply
 *                  callback. If this resolve call is using information previously saved
 *                  (e.g. in a preference file) for later use, then use interfaceIndex 0, because
 *                  the desired service may now be reachable via a different physical interface.
 *                  See "Constants for specifying an interface index" for more details.
 *
 * name:            The name of the service instance to be resolved, as reported to the
 *                  DNSServiceBrowseReply() callback.
 *
 * regtype:         The type of the service instance to be resolved, as reported to the
 *                  DNSServiceBrowseReply() callback.
 *
 * domain:          The domain of the service instance to be resolved, as reported to the
 *                  DNSServiceBrowseReply() callback.
 *
 * callBack:        The function to be called when a result is found, or if the call
 *                  asynchronously fails.
 *
 * context:         An application context pointer which is passed to the callback function
 *                  (may be NULL).
 *
 * return value:    Returns kDNSServiceErr_NoError on succeses (any subsequent, asynchronous
 *                  errors are delivered to the callback), otherwise returns an error code indicating
 *                  the error that occurred (the callback is never invoked and the DNSServiceRef
 *                  is not initialized.)
 */

DNSServiceErrorType DNSSD_API DNSServiceResolve
    (
    DNSServiceRef                       *sdRef,
    DNSServiceFlags                     flags,
    uint32_t                            interfaceIndex,
    const char                          *name,
    const char                          *regtype,
    const char                          *domain,
    DNSServiceResolveReply              callBack,
    void                                *context  /* may be NULL */
    );


/*********************************************************************************************
 *
 *  Special Purpose Calls (most applications will not use these)
 *
 *********************************************************************************************/

/* DNSServiceCreateConnection()
 *
 * Create a connection to the daemon allowing efficient registration of
 * multiple individual records.
 *
 *
 * Parameters:
 *
 * sdRef:           A pointer to an uninitialized DNSServiceRef.  Deallocating
 *                  the reference (via DNSServiceRefDeallocate()) severs the
 *                  connection and deregisters all records registered on this connection.
 *
 * return value:    Returns kDNSServiceErr_NoError on success, otherwise returns
 *                  an error code indicating the specific failure that occurred (in which
 *                  case the DNSServiceRef is not initialized).
 */

DNSServiceErrorType DNSSD_API DNSServiceCreateConnection(DNSServiceRef *sdRef);


/* DNSServiceRegisterRecord
 *
 * Register an individual resource record on a connected DNSServiceRef.
 *
 * Note that name conflicts occurring for records registered via this call must be handled
 * by the client in the callback.
 *
 *
 * DNSServiceRegisterRecordReply() parameters:
 *
 * sdRef:           The connected DNSServiceRef initialized by
 *                  DNSServiceCreateConnection().
 *
 * RecordRef:       The DNSRecordRef initialized by DNSServiceRegisterRecord().  If the above
 *                  DNSServiceRef is passed to DNSServiceRefDeallocate(), this DNSRecordRef is
 *                  invalidated, and may not be used further.
 *
 * flags:           Currently unused, reserved for future use.
 *
 * errorCode:       Will be kDNSServiceErr_NoError on success, otherwise will
 *                  indicate the failure that occurred (including name conflicts.)
 *                  Other parameters are undefined if errorCode is nonzero.
 *
 * context:         The context pointer that was passed to the callout.
 *
 */

 typedef void (DNSSD_API *DNSServiceRegisterRecordReply)
    (
    DNSServiceRef                       sdRef,
    DNSRecordRef                        RecordRef,
    DNSServiceFlags                     flags,
    DNSServiceErrorType                 errorCode,
    void                                *context
    );


/* DNSServiceRegisterRecord() Parameters:
 *
 * sdRef:           A DNSServiceRef initialized by DNSServiceCreateConnection().
 *
 * RecordRef:       A pointer to an uninitialized DNSRecordRef.  Upon succesfull completion of this
 *                  call, this ref may be passed to DNSServiceUpdateRecord() or DNSServiceRemoveRecord().
 *                  (To deregister ALL records registered on a single connected DNSServiceRef
 *                  and deallocate each of their corresponding DNSServiceRecordRefs, call
 *                  DNSServiceRefDealloocate()).
 *
 * flags:           Possible values are kDNSServiceFlagsShared or kDNSServiceFlagsUnique
 *                  (see flag type definitions for details).
 *
 * interfaceIndex:  If non-zero, specifies the interface on which to register the record
 *                  (the index for a given interface is determined via the if_nametoindex()
 *                  family of calls.)  Passing 0 causes the record to be registered on all interfaces.
 *                  See "Constants for specifying an interface index" for more details.
 *
 * fullname:        The full domain name of the resource record.
 *
 * rrtype:          The numerical type of the resource record (e.g. kDNSServiceType_PTR, kDNSServiceType_SRV, etc)
 *
 * rrclass:         The class of the resource record (usually kDNSServiceClass_IN)
 *
 * rdlen:           Length, in bytes, of the rdata.
 *
 * rdata:           A pointer to the raw rdata, as it is to appear in the DNS record.
 *
 * ttl:             The time to live of the resource record, in seconds.  Pass 0 to use a default value.
 *
 * callBack:        The function to be called when a result is found, or if the call
 *                  asynchronously fails (e.g. because of a name conflict.)
 *
 * context:         An application context pointer which is passed to the callback function
 *                  (may be NULL).
 *
 * return value:    Returns kDNSServiceErr_NoError on succeses (any subsequent, asynchronous
 *                  errors are delivered to the callback), otherwise returns an error code indicating
 *                  the error that occurred (the callback is never invoked and the DNSRecordRef is
 *                  not initialized.)
 */

DNSServiceErrorType DNSSD_API DNSServiceRegisterRecord
    (
    DNSServiceRef                       sdRef,
    DNSRecordRef                        *RecordRef,
    DNSServiceFlags                     flags,
    uint32_t                            interfaceIndex,
    const char                          *fullname,
    uint16_t                            rrtype,
    uint16_t                            rrclass,
    uint16_t                            rdlen,
    const void                          *rdata,
    uint32_t                            ttl,
    DNSServiceRegisterRecordReply       callBack,
    void                                *context    /* may be NULL */
    );


/* DNSServiceQueryRecord
 *
 * Query for an arbitrary DNS record.
 *
 *
 * DNSServiceQueryRecordReply() Callback Parameters:
 *
 * sdRef:           The DNSServiceRef initialized by DNSServiceQueryRecord().
 *
 * flags:           Possible values are kDNSServiceFlagsMoreComing and
 *                  kDNSServiceFlagsAdd.  The Add flag is NOT set for PTR records
 *                  with a ttl of 0, i.e. "Remove" events.
 *
 * interfaceIndex:  The interface on which the query was resolved (the index for a given
 *                  interface is determined via the if_nametoindex() family of calls).
 *                  See "Constants for specifying an interface index" for more details.
 *
 * errorCode:       Will be kDNSServiceErr_NoError on success, otherwise will
 *                  indicate the failure that occurred.  Other parameters are undefined if
 *                  errorCode is nonzero.
 *
 * fullname:        The resource record's full domain name.
 *
 * rrtype:          The resource record's type (e.g. kDNSServiceType_PTR, kDNSServiceType_SRV, etc)
 *
 * rrclass:         The class of the resource record (usually kDNSServiceClass_IN).
 *
 * rdlen:           The length, in bytes, of the resource record rdata.
 *
 * rdata:           The raw rdata of the resource record.
 *
 * ttl:             The resource record's time to live, in seconds.
 *
 * context:         The context pointer that was passed to the callout.
 *
 */

typedef void (DNSSD_API *DNSServiceQueryRecordReply)
    (
    DNSServiceRef                       DNSServiceRef,
    DNSServiceFlags                     flags,
    uint32_t                            interfaceIndex,
    DNSServiceErrorType                 errorCode,
    const char                          *fullname,
    uint16_t                            rrtype,
    uint16_t                            rrclass,
    uint16_t                            rdlen,
    const void                          *rdata,
    uint32_t                            ttl,
    void                                *context
    );


/* DNSServiceQueryRecord() Parameters:
 *
 * sdRef:           A pointer to an uninitialized DNSServiceRef. If the call succeeds
 *                  then it initializes the DNSServiceRef, returns kDNSServiceErr_NoError,
 *                  and the query operation will run indefinitely until the client
 *                  terminates it by passing this DNSServiceRef to DNSServiceRefDeallocate().
 *
 * flags:           Pass kDNSServiceFlagsLongLivedQuery to create a "long-lived" unicast
 *                  query in a non-local domain.  Without setting this flag, unicast queries
 *                  will be one-shot - that is, only answers available at the time of the call
 *                  will be returned.  By setting this flag, answers (including Add and Remove
 *                  events) that become available after the initial call is made will generate
 *                  callbacks.  This flag has no effect on link-local multicast queries.
 *
 * interfaceIndex:  If non-zero, specifies the interface on which to issue the query
 *                  (the index for a given interface is determined via the if_nametoindex()
 *                  family of calls.)  Passing 0 causes the name to be queried for on all
 *                  interfaces. See "Constants for specifying an interface index" for more details.
 *
 * fullname:        The full domain name of the resource record to be queried for.
 *
 * rrtype:          The numerical type of the resource record to be queried for
 *                  (e.g. kDNSServiceType_PTR, kDNSServiceType_SRV, etc)
 *
 * rrclass:         The class of the resource record (usually kDNSServiceClass_IN).
 *
 * callBack:        The function to be called when a result is found, or if the call
 *                  asynchronously fails.
 *
 * context:         An application context pointer which is passed to the callback function
 *                  (may be NULL).
 *
 * return value:    Returns kDNSServiceErr_NoError on succeses (any subsequent, asynchronous
 *                  errors are delivered to the callback), otherwise returns an error code indicating
 *                  the error that occurred (the callback is never invoked and the DNSServiceRef
 *                  is not initialized.)
 */

DNSServiceErrorType DNSSD_API DNSServiceQueryRecord
    (
    DNSServiceRef                       *sdRef,
    DNSServiceFlags                     flags,
    uint32_t                            interfaceIndex,
    const char                          *fullname,
    uint16_t                            rrtype,
    uint16_t                            rrclass,
    DNSServiceQueryRecordReply          callBack,
    void                                *context  /* may be NULL */
    );


/* DNSServiceReconfirmRecord
 *
 * Instruct the daemon to verify the validity of a resource record that appears to
 * be out of date (e.g. because tcp connection to a service's target failed.)
 * Causes the record to be flushed from the daemon's cache (as well as all other
 * daemons' caches on the network) if the record is determined to be invalid.
 *
 * Parameters:
 *
 * flags:           Currently unused, reserved for future use.
 *
 * interfaceIndex:  If non-zero, specifies the interface of the record in question.
 *                  Passing 0 causes all instances of this record to be reconfirmed.
 *
 * fullname:        The resource record's full domain name.
 *
 * rrtype:          The resource record's type (e.g. kDNSServiceType_PTR, kDNSServiceType_SRV, etc)
 *
 * rrclass:         The class of the resource record (usually kDNSServiceClass_IN).
 *
 * rdlen:           The length, in bytes, of the resource record rdata.
 *
 * rdata:           The raw rdata of the resource record.
 *
 */

DNSServiceErrorType DNSSD_API DNSServiceReconfirmRecord
    (
    DNSServiceFlags                    flags,
    uint32_t                           interfaceIndex,
    const char                         *fullname,
    uint16_t                           rrtype,
    uint16_t                           rrclass,
    uint16_t                           rdlen,
    const void                         *rdata
    );


/*********************************************************************************************
 *
 *  General Utility Functions
 *
 *********************************************************************************************/

/* DNSServiceConstructFullName()
 *
 * Concatenate a three-part domain name (as returned by the above callbacks) into a
 * properly-escaped full domain name. Note that callbacks in the above functions ALREADY ESCAPE
 * strings where necessary.
 *
 * Parameters:
 *
 * fullName:        A pointer to a buffer that where the resulting full domain name is to be written.
 *                  The buffer must be kDNSServiceMaxDomainName (1005) bytes in length to
 *                  accommodate the longest legal domain name without buffer overrun.
 *
 * service:         The service name - any dots or backslashes must NOT be escaped.
 *                  May be NULL (to construct a PTR record name, e.g.
 *                  "_ftp._tcp.apple.com.").
 *
 * regtype:         The service type followed by the protocol, separated by a dot
 *                  (e.g. "_ftp._tcp").
 *
 * domain:          The domain name, e.g. "apple.com.".  Literal dots or backslashes,
 *                  if any, must be escaped, e.g. "1st\. Floor.apple.com."
 *
 * return value:    Returns 0 on success, -1 on error.
 *
 */

int DNSSD_API DNSServiceConstructFullName
    (
    char                            *fullName,
    const char                      *service,      /* may be NULL */
    const char                      *regtype,
    const char                      *domain
    );


/*********************************************************************************************
 *
 *   TXT Record Construction Functions
 *
 *********************************************************************************************/

/*
 * A typical calling sequence for TXT record construction is something like:
 *
 * Client allocates storage for TXTRecord data (e.g. declare buffer on the stack)
 * TXTRecordCreate();
 * TXTRecordSetValue();
 * TXTRecordSetValue();
 * TXTRecordSetValue();
 * ...
 * DNSServiceRegister( ... TXTRecordGetLength(), TXTRecordGetBytesPtr() ... );
 * TXTRecordDeallocate();
 * Explicitly deallocate storage for TXTRecord data (if not allocated on the stack)
 */


/* TXTRecordRef
 *
 * Opaque internal data type.
 * Note: Represents a DNS-SD TXT record.
 */

typedef union _TXTRecordRef_t { char PrivateData[16]; char *ForceNaturalAlignment; } TXTRecordRef;


/* TXTRecordCreate()
 *
 * Creates a new empty TXTRecordRef referencing the specified storage.
 *
 * If the buffer parameter is NULL, or the specified storage size is not
 * large enough to hold a key subsequently added using TXTRecordSetValue(),
 * then additional memory will be added as needed using malloc().
 *
 * On some platforms, when memory is low, malloc() may fail. In this
 * case, TXTRecordSetValue() will return kDNSServiceErr_NoMemory, and this
 * error condition will need to be handled as appropriate by the caller.
 *
 * You can avoid the need to handle this error condition if you ensure
 * that the storage you initially provide is large enough to hold all
 * the key/value pairs that are to be added to the record.
 * The caller can precompute the exact length required for all of the
 * key/value pairs to be added, or simply provide a fixed-sized buffer
 * known in advance to be large enough.
 * A no-value (key-only) key requires  (1 + key length) bytes.
 * A key with empty value requires     (1 + key length + 1) bytes.
 * A key with non-empty value requires (1 + key length + 1 + value length).
 * For most applications, DNS-SD TXT records are generally
 * less than 100 bytes, so in most cases a simple fixed-sized
 * 256-byte buffer will be more than sufficient.
 * Recommended size limits for DNS-SD TXT Records are discussed in
 * <http://files.dns-sd.org/draft-cheshire-dnsext-dns-sd.txt>
 *
 * Note: When passing parameters to and from these TXT record APIs,
 * the key name does not include the '=' character. The '=' character
 * is the separator between the key and value in the on-the-wire
 * packet format; it is not part of either the key or the value.
 *
 * txtRecord:       A pointer to an uninitialized TXTRecordRef.
 *
 * bufferLen:       The size of the storage provided in the "buffer" parameter.
 *
 * buffer:          Optional caller-supplied storage used to hold the TXTRecord data.
 *                  This storage must remain valid for as long as
 *                  the TXTRecordRef.
 */

void DNSSD_API TXTRecordCreate
    (
    TXTRecordRef     *txtRecord,
    uint16_t         bufferLen,
    void             *buffer
    );


/* TXTRecordDeallocate()
 *
 * Releases any resources allocated in the course of preparing a TXT Record
 * using TXTRecordCreate()/TXTRecordSetValue()/TXTRecordRemoveValue().
 * Ownership of the buffer provided in TXTRecordCreate() returns to the client.
 *
 * txtRecord:           A TXTRecordRef initialized by calling TXTRecordCreate().
 *
 */

void DNSSD_API TXTRecordDeallocate
    (
    TXTRecordRef     *txtRecord
    );


/* TXTRecordSetValue()
 *
 * Adds a key (optionally with value) to a TXTRecordRef. If the "key" already
 * exists in the TXTRecordRef, then the current value will be replaced with
 * the new value.
 * Keys may exist in four states with respect to a given TXT record:
 *  - Absent (key does not appear at all)
 *  - Present with no value ("key" appears alone)
 *  - Present with empty value ("key=" appears in TXT record)
 *  - Present with non-empty value ("key=value" appears in TXT record)
 * For more details refer to "Data Syntax for DNS-SD TXT Records" in
 * <http://files.dns-sd.org/draft-cheshire-dnsext-dns-sd.txt>
 *
 * txtRecord:       A TXTRecordRef initialized by calling TXTRecordCreate().
 *
 * key:             A null-terminated string which only contains printable ASCII
 *                  values (0x20-0x7E), excluding '=' (0x3D). Keys should be
 *                  8 characters or less (not counting the terminating null).
 *
 * valueSize:       The size of the value.
 *
 * value:           Any binary value. For values that represent
 *                  textual data, UTF-8 is STRONGLY recommended.
 *                  For values that represent textual data, valueSize
 *                  should NOT include the terminating null (if any)
 *                  at the end of the string.
 *                  If NULL, then "key" will be added with no value.
 *                  If non-NULL but valueSize is zero, then "key=" will be
 *                  added with empty value.
 *
 * return value:    Returns kDNSServiceErr_NoError on success.
 *                  Returns kDNSServiceErr_Invalid if the "key" string contains
 *                  illegal characters.
 *                  Returns kDNSServiceErr_NoMemory if adding this key would
 *                  exceed the available storage.
 */

DNSServiceErrorType DNSSD_API TXTRecordSetValue
    (
    TXTRecordRef     *txtRecord,
    const char       *key,
    uint8_t          valueSize,        /* may be zero */
    const void       *value            /* may be NULL */
    );


/* TXTRecordRemoveValue()
 *
 * Removes a key from a TXTRecordRef.  The "key" must be an
 * ASCII string which exists in the TXTRecordRef.
 *
 * txtRecord:       A TXTRecordRef initialized by calling TXTRecordCreate().
 *
 * key:             A key name which exists in the TXTRecordRef.
 *
 * return value:    Returns kDNSServiceErr_NoError on success.
 *                  Returns kDNSServiceErr_NoSuchKey if the "key" does not
 *                  exist in the TXTRecordRef.
 */

DNSServiceErrorType DNSSD_API TXTRecordRemoveValue
    (
    TXTRecordRef     *txtRecord,
    const char       *key
    );


/* TXTRecordGetLength()
 *
 * Allows you to determine the length of the raw bytes within a TXTRecordRef.
 *
 * txtRecord:       A TXTRecordRef initialized by calling TXTRecordCreate().
 *
 * return value:    Returns the size of the raw bytes inside a TXTRecordRef
 *                  which you can pass directly to DNSServiceRegister() or
 *                  to DNSServiceUpdateRecord().
 *                  Returns 0 if the TXTRecordRef is empty.
 */

uint16_t DNSSD_API TXTRecordGetLength
    (
    const TXTRecordRef *txtRecord
    );


/* TXTRecordGetBytesPtr()
 *
 * Allows you to retrieve a pointer to the raw bytes within a TXTRecordRef.
 *
 * txtRecord:       A TXTRecordRef initialized by calling TXTRecordCreate().
 *
 * return value:    Returns a pointer to the raw bytes inside the TXTRecordRef
 *                  which you can pass directly to DNSServiceRegister() or
 *                  to DNSServiceUpdateRecord().
 */

const void * DNSSD_API TXTRecordGetBytesPtr
    (
    const TXTRecordRef *txtRecord
    );


/*********************************************************************************************
 *
 *   TXT Record Parsing Functions
 *
 *********************************************************************************************/

/*
 * A typical calling sequence for TXT record parsing is something like:
 *
 * Receive TXT record data in DNSServiceResolve() callback
 * if (TXTRecordContainsKey(txtLen, txtRecord, "key")) then do something
 * val1ptr = TXTRecordGetValuePtr(txtLen, txtRecord, "key1", &len1);
 * val2ptr = TXTRecordGetValuePtr(txtLen, txtRecord, "key2", &len2);
 * ...
 * bcopy(val1ptr, myval1, len1);
 * bcopy(val2ptr, myval2, len2);
 * ...
 * return;
 *
 * If you wish to retain the values after return from the DNSServiceResolve()
 * callback, then you need to copy the data to your own storage using bcopy()
 * or similar, as shown in the example above.
 *
 * If for some reason you need to parse a TXT record you built yourself
 * using the TXT record construction functions above, then you can do
 * that using TXTRecordGetLength and TXTRecordGetBytesPtr calls:
 * TXTRecordGetValue(TXTRecordGetLength(x), TXTRecordGetBytesPtr(x), key, &len);
 *
 * Most applications only fetch keys they know about from a TXT record and
 * ignore the rest.
 * However, some debugging tools wish to fetch and display all keys.
 * To do that, use the TXTRecordGetCount() and TXTRecordGetItemAtIndex() calls.
 */

/* TXTRecordContainsKey()
 *
 * Allows you to determine if a given TXT Record contains a specified key.
 *
 * txtLen:          The size of the received TXT Record.
 *
 * txtRecord:       Pointer to the received TXT Record bytes.
 *
 * key:             A null-terminated ASCII string containing the key name.
 *
 * return value:    Returns 1 if the TXT Record contains the specified key.
 *                  Otherwise, it returns 0.
 */

int DNSSD_API TXTRecordContainsKey
    (
    uint16_t         txtLen,
    const void       *txtRecord,
    const char       *key
    );


/* TXTRecordGetValuePtr()
 *
 * Allows you to retrieve the value for a given key from a TXT Record.
 *
 * txtLen:          The size of the received TXT Record
 *
 * txtRecord:       Pointer to the received TXT Record bytes.
 *
 * key:             A null-terminated ASCII string containing the key name.
 *
 * valueLen:        On output, will be set to the size of the "value" data.
 *
 * return value:    Returns NULL if the key does not exist in this TXT record,
 *                  or exists with no value (to differentiate between
 *                  these two cases use TXTRecordContainsKey()).
 *                  Returns pointer to location within TXT Record bytes
 *                  if the key exists with empty or non-empty value.
 *                  For empty value, valueLen will be zero.
 *                  For non-empty value, valueLen will be length of value data.
 */

const void * DNSSD_API TXTRecordGetValuePtr
    (
    uint16_t         txtLen,
    const void       *txtRecord,
    const char       *key,
    uint8_t          *valueLen
    );


/* TXTRecordGetCount()
 *
 * Returns the number of keys stored in the TXT Record.  The count
 * can be used with TXTRecordGetItemAtIndex() to iterate through the keys.
 *
 * txtLen:          The size of the received TXT Record.
 *
 * txtRecord:       Pointer to the received TXT Record bytes.
 *
 * return value:    Returns the total number of keys in the TXT Record.
 *
 */

uint16_t DNSSD_API TXTRecordGetCount
    (
    uint16_t         txtLen,
    const void       *txtRecord
    );


/* TXTRecordGetItemAtIndex()
 *
 * Allows you to retrieve a key name and value pointer, given an index into
 * a TXT Record.  Legal index values range from zero to TXTRecordGetCount()-1.
 * It's also possible to iterate through keys in a TXT record by simply
 * calling TXTRecordGetItemAtIndex() repeatedly, beginning with index zero
 * and increasing until TXTRecordGetItemAtIndex() returns kDNSServiceErr_Invalid.
 *
 * On return:
 * For keys with no value, *value is set to NULL and *valueLen is zero.
 * For keys with empty value, *value is non-NULL and *valueLen is zero.
 * For keys with non-empty value, *value is non-NULL and *valueLen is non-zero.
 *
 * txtLen:          The size of the received TXT Record.
 *
 * txtRecord:       Pointer to the received TXT Record bytes.
 *
 * index:           An index into the TXT Record.
 *
 * keyBufLen:       The size of the string buffer being supplied.
 *
 * key:             A string buffer used to store the key name.
 *                  On return, the buffer contains a null-terminated C string
 *                  giving the key name. DNS-SD TXT keys are usually
 *                  8 characters or less. To hold the maximum possible
 *                  key name, the buffer should be 256 bytes long.
 *
 * valueLen:        On output, will be set to the size of the "value" data.
 *
 * value:           On output, *value is set to point to location within TXT
 *                  Record bytes that holds the value data.
 *
 * return value:    Returns kDNSServiceErr_NoError on success.
 *                  Returns kDNSServiceErr_NoMemory if keyBufLen is too short.
 *                  Returns kDNSServiceErr_Invalid if index is greater than
 *                  TXTRecordGetCount()-1.
 */

DNSServiceErrorType DNSSD_API TXTRecordGetItemAtIndex
    (
    uint16_t         txtLen,
    const void       *txtRecord,
    uint16_t         index,
    uint16_t         keyBufLen,
    char             *key,
    uint8_t          *valueLen,
    const void       **value
    );

#ifdef __APPLE_API_PRIVATE

/*
 * Mac OS X specific functionality
 * 3rd party clients of this API should not depend on future support or availability of this routine
 */

/* DNSServiceSetDefaultDomainForUser()
 *
 * Set the default domain for the caller's UID.  Future browse and registration
 * calls by this user that do not specify an explicit domain will browse and
 * register in this wide-area domain in addition to .local.  In addition, this
 * domain will be returned as a Browse domain via domain enumeration calls.
 *
 *
 * Parameters:
 *
 * flags:           Pass kDNSServiceFlagsAdd to add a domain for a user.  Call without
 *                  this flag set to clear a previously added domain.
 *
 * domain:          The domain to be used for the caller's UID.
 *
 * return value:    Returns kDNSServiceErr_NoError on succeses, otherwise returns
 *                  an error code indicating the error that occurred
 */

DNSServiceErrorType DNSSD_API DNSServiceSetDefaultDomainForUser
    (
    DNSServiceFlags                    flags,
    const char                         *domain
    );

#endif //__APPLE_API_PRIVATE

// Some C compiler cleverness. We can make the compiler check certain things for us,
// and report errors at compile-time if anything is wrong. The usual way to do this would
// be to use a run-time "if" statement or the conventional run-time "assert" mechanism, but
// then you don't find out what's wrong until you run the software. This way, if the assertion
// condition is false, the array size is negative, and the complier complains immediately.

struct DNS_SD_CompileTimeAssertionChecks
	{
	char assert0[(sizeof(union _TXTRecordRef_t) == 16) ? 1 : -1];
	};

#ifdef  __cplusplus
    }
#endif

#endif  /* _DNS_SD_H */