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28 
29 
30 /*! @header     DNS Service Discovery
31  *
32  * @discussion  This section describes the functions, callbacks, and data structures
33  *              that make up the DNS Service Discovery API.
34  *
35  *              The DNS Service Discovery API is part of Bonjour, Apple's implementation
36  *              of zero-configuration networking (ZEROCONF).
37  *
38  *              Bonjour allows you to register a network service, such as a
39  *              printer or file server, so that it can be found by name or browsed
40  *              for by service type and domain. Using Bonjour, applications can
41  *              discover what services are available on the network, along with
42  *              all the information -- such as name, IP address, and port --
43  *              necessary to access a particular service.
44  *
45  *              In effect, Bonjour combines the functions of a local DNS server and
46  *              AppleTalk. Bonjour allows applications to provide user-friendly printer
47  *              and server browsing, among other things, over standard IP networks.
48  *              This behavior is a result of combining protocols such as multicast and
49  *              DNS to add new functionality to the network (such as multicast DNS).
50  *
51  *              Bonjour gives applications easy access to services over local IP
52  *              networks without requiring the service or the application to support
53  *              an AppleTalk or a Netbeui stack, and without requiring a DNS server
54  *              for the local network.
55  */
56 
57 
58 /* _DNS_SD_H contains the mDNSResponder version number for this header file, formatted as follows:
59  *   Major part of the build number * 10000 +
60  *   minor part of the build number *   100
61  * For example, Mac OS X 10.4.9 has mDNSResponder-108.4, which would be represented as
62  * version 1080400. This allows C code to do simple greater-than and less-than comparisons:
63  * e.g. an application that requires the DNSServiceGetProperty() call (new in mDNSResponder-126) can check:
64  *
65  *   #if _DNS_SD_H+0 >= 1260000
66  *   ... some C code that calls DNSServiceGetProperty() ...
67  *   #endif
68  *
69  * The version defined in this header file symbol allows for compile-time
70  * checking, so that C code building with earlier versions of the header file
71  * can avoid compile errors trying to use functions that aren't even defined
72  * in those earlier versions. Similar checks may also be performed at run-time:
73  *  => weak linking -- to avoid link failures if run with an earlier
74  *     version of the library that's missing some desired symbol, or
75  *  => DNSServiceGetProperty(DaemonVersion) -- to verify whether the running daemon
76  *     ("system service" on Windows) meets some required minimum functionality level.
77  */
78 
79 #ifndef _DNS_SD_H
80 #define _DNS_SD_H 2120100
81 
82 #ifdef  __cplusplus
83     extern "C" {
84 #endif
85 
86 /* standard calling convention under Win32 is __stdcall */
87 /* Note: When compiling Intel EFI (Extensible Firmware Interface) under MS Visual Studio, the */
88 /* _WIN32 symbol is defined by the compiler even though it's NOT compiling code for Windows32 */
89 #if defined(_WIN32) && !defined(EFI32) && !defined(EFI64)
90 #define DNSSD_API __stdcall
91 #else
92 #define DNSSD_API
93 #endif
94 
95 /* stdint.h does not exist on FreeBSD 4.x; its types are defined in sys/types.h instead */
96 #if defined(__FreeBSD__) && (__FreeBSD__ < 5)
97 #include <sys/types.h>
98 
99 /* Likewise, on Sun, standard integer types are in sys/types.h */
100 #elif defined(__sun__)
101 #include <sys/types.h>
102 
103 /* EFI does not have stdint.h, or anything else equivalent */
104 #elif defined(EFI32) || defined(EFI64) || defined(EFIX64)
105 #include "Tiano.h"
106 #if !defined(_STDINT_H_)
107 typedef UINT8       uint8_t;
108 typedef INT8        int8_t;
109 typedef UINT16      uint16_t;
110 typedef INT16       int16_t;
111 typedef UINT32      uint32_t;
112 typedef INT32       int32_t;
113 #endif
114 /* Windows has its own differences */
115 #elif defined(_WIN32)
116 #include <windows.h>
117 #define _UNUSED
118 #ifndef _MSL_STDINT_H
119 typedef UINT8       uint8_t;
120 typedef INT8        int8_t;
121 typedef UINT16      uint16_t;
122 typedef INT16       int16_t;
123 typedef UINT32      uint32_t;
124 typedef INT32       int32_t;
125 #endif
126 
127 /* All other Posix platforms use stdint.h */
128 #else
129 #include <stdint.h>
130 #endif
131 
132 /* DNSServiceRef, DNSRecordRef
133  *
134  * Opaque internal data types.
135  * Note: client is responsible for serializing access to these structures if
136  * they are shared between concurrent threads.
137  */
138 
139 typedef struct _DNSServiceRef_t *DNSServiceRef;
140 typedef struct _DNSRecordRef_t *DNSRecordRef;
141 
142 struct sockaddr;
143 
144 /*! @enum General flags
145  * Most DNS-SD API functions and callbacks include a DNSServiceFlags parameter.
146  * As a general rule, any given bit in the 32-bit flags field has a specific fixed meaning,
147  * regardless of the function or callback being used. For any given function or callback,
148  * typically only a subset of the possible flags are meaningful, and all others should be zero.
149  * The discussion section for each API call describes which flags are valid for that call
150  * and callback. In some cases, for a particular call, it may be that no flags are currently
151  * defined, in which case the DNSServiceFlags parameter exists purely to allow future expansion.
152  * In all cases, developers should expect that in future releases, it is possible that new flag
153  * values will be defined, and write code with this in mind. For example, code that tests
154  *     if (flags == kDNSServiceFlagsAdd) ...
155  * will fail if, in a future release, another bit in the 32-bit flags field is also set.
156  * The reliable way to test whether a particular bit is set is not with an equality test,
157  * but with a bitwise mask:
158  *     if (flags & kDNSServiceFlagsAdd) ...
159  */
160 enum
161     {
162     kDNSServiceFlagsMoreComing          = 0x1,
163     /* MoreComing indicates to a callback that at least one more result is
164      * queued and will be delivered following immediately after this one.
165      * When the MoreComing flag is set, applications should not immediately
166      * update their UI, because this can result in a great deal of ugly flickering
167      * on the screen, and can waste a great deal of CPU time repeatedly updating
168      * the screen with content that is then immediately erased, over and over.
169      * Applications should wait until until MoreComing is not set, and then
170      * update their UI when no more changes are imminent.
171      * When MoreComing is not set, that doesn't mean there will be no more
172      * answers EVER, just that there are no more answers immediately
173      * available right now at this instant. If more answers become available
174      * in the future they will be delivered as usual.
175      */
176 
177     kDNSServiceFlagsAdd                 = 0x2,
178     kDNSServiceFlagsDefault             = 0x4,
179     /* Flags for domain enumeration and browse/query reply callbacks.
180      * "Default" applies only to enumeration and is only valid in
181      * conjunction with "Add". An enumeration callback with the "Add"
182      * flag NOT set indicates a "Remove", i.e. the domain is no longer
183      * valid.
184      */
185 
186     kDNSServiceFlagsNoAutoRename        = 0x8,
187     /* Flag for specifying renaming behavior on name conflict when registering
188      * non-shared records. By default, name conflicts are automatically handled
189      * by renaming the service. NoAutoRename overrides this behavior - with this
190      * flag set, name conflicts will result in a callback. The NoAutorename flag
191      * is only valid if a name is explicitly specified when registering a service
192      * (i.e. the default name is not used.)
193      */
194 
195     kDNSServiceFlagsShared              = 0x10,
196     kDNSServiceFlagsUnique              = 0x20,
197     /* Flag for registering individual records on a connected
198      * DNSServiceRef. Shared indicates that there may be multiple records
199      * with this name on the network (e.g. PTR records). Unique indicates that the
200      * record's name is to be unique on the network (e.g. SRV records).
201      */
202 
203     kDNSServiceFlagsBrowseDomains       = 0x40,
204     kDNSServiceFlagsRegistrationDomains = 0x80,
205     /* Flags for specifying domain enumeration type in DNSServiceEnumerateDomains.
206      * BrowseDomains enumerates domains recommended for browsing, RegistrationDomains
207      * enumerates domains recommended for registration.
208      */
209 
210     kDNSServiceFlagsLongLivedQuery      = 0x100,
211     /* Flag for creating a long-lived unicast query for the DNSServiceQueryRecord call. */
212 
213     kDNSServiceFlagsAllowRemoteQuery    = 0x200,
214     /* Flag for creating a record for which we will answer remote queries
215      * (queries from hosts more than one hop away; hosts not directly connected to the local link).
216      */
217 
218     kDNSServiceFlagsForceMulticast      = 0x400,
219     /* Flag for signifying that a query or registration should be performed exclusively via multicast
220      * DNS, even for a name in a domain (e.g. foo.apple.com.) that would normally imply unicast DNS.
221      */
222 
223     kDNSServiceFlagsForce               = 0x800,
224     /* Flag for signifying a "stronger" variant of an operation.
225      * Currently defined only for DNSServiceReconfirmRecord(), where it forces a record to
226      * be removed from the cache immediately, instead of querying for a few seconds before
227      * concluding that the record is no longer valid and then removing it. This flag should
228      * be used with caution because if a service browsing PTR record is indeed still valid
229      * on the network, forcing its removal will result in a user-interface flap -- the
230      * discovered service instance will disappear, and then re-appear moments later.
231      */
232 
233     kDNSServiceFlagsReturnIntermediates = 0x1000,
234     /* Flag for returning intermediate results.
235      * For example, if a query results in an authoritative NXDomain (name does not exist)
236      * then that result is returned to the client. However the query is not implicitly
237      * cancelled -- it remains active and if the answer subsequently changes
238      * (e.g. because a VPN tunnel is subsequently established) then that positive
239      * result will still be returned to the client.
240      * Similarly, if a query results in a CNAME record, then in addition to following
241      * the CNAME referral, the intermediate CNAME result is also returned to the client.
242      * When this flag is not set, NXDomain errors are not returned, and CNAME records
243      * are followed silently without informing the client of the intermediate steps.
244      * (In earlier builds this flag was briefly calledkDNSServiceFlagsReturnCNAME)
245      */
246 
247     kDNSServiceFlagsNonBrowsable        = 0x2000,
248     /* A service registered with the NonBrowsable flag set can be resolved using
249      * DNSServiceResolve(), but will not be discoverable using DNSServiceBrowse().
250      * This is for cases where the name is actually a GUID; it is found by other means;
251      * there is no end-user benefit to browsing to find a long list of opaque GUIDs.
252      * Using the NonBrowsable flag creates SRV+TXT without the cost of also advertising
253      * an associated PTR record.
254      */
255 
256     kDNSServiceFlagsShareConnection     = 0x4000,
257     /* For efficiency, clients that perform many concurrent operations may want to use a
258      * single Unix Domain Socket connection with the background daemon, instead of having a
259      * separate connection for each independent operation. To use this mode, clients first
260      * call DNSServiceCreateConnection(&MainRef) to initialize the main DNSServiceRef.
261      * For each subsequent operation that is to share that same connection, the client copies
262      * the MainRef, and then passes the address of that copy, setting the ShareConnection flag
263      * to tell the library that this DNSServiceRef is not a typical uninitialized DNSServiceRef;
264      * it's a copy of an existing DNSServiceRef whose connection information should be reused.
265      *
266      * For example:
267      *
268      * DNSServiceErrorType error;
269      * DNSServiceRef MainRef;
270      * error = DNSServiceCreateConnection(&MainRef);
271      * if (error) ...
272      * DNSServiceRef BrowseRef = MainRef;  // Important: COPY the primary DNSServiceRef first...
273      * error = DNSServiceBrowse(&BrowseRef, kDNSServiceFlagsShareConnection, ...); // then use the copy
274      * if (error) ...
275      * ...
276      * DNSServiceRefDeallocate(BrowseRef); // Terminate the browse operation
277      * DNSServiceRefDeallocate(MainRef);   // Terminate the shared connection
278      *
279      * Notes:
280      *
281      * 1. Collective kDNSServiceFlagsMoreComing flag
282      * When callbacks are invoked using a shared DNSServiceRef, the
283      * kDNSServiceFlagsMoreComing flag applies collectively to *all* active
284      * operations sharing the same parent DNSServiceRef. If the MoreComing flag is
285      * set it means that there are more results queued on this parent DNSServiceRef,
286      * but not necessarily more results for this particular callback function.
287      * The implication of this for client programmers is that when a callback
288      * is invoked with the MoreComing flag set, the code should update its
289      * internal data structures with the new result, and set a variable indicating
290      * that its UI needs to be updated. Then, later when a callback is eventually
291      * invoked with the MoreComing flag not set, the code should update *all*
292      * stale UI elements related to that shared parent DNSServiceRef that need
293      * updating, not just the UI elements related to the particular callback
294      * that happened to be the last one to be invoked.
295      *
296      * 2. Canceling operations and kDNSServiceFlagsMoreComing
297      * Whenever you cancel any operation for which you had deferred UI updates
298      * waiting because of a kDNSServiceFlagsMoreComing flag, you should perform
299      * those deferred UI updates. This is because, after cancelling the operation,
300      * you can no longer wait for a callback *without* MoreComing set, to tell
301      * you do perform your deferred UI updates (the operation has been canceled,
302      * so there will be no more callbacks). An implication of the collective
303      * kDNSServiceFlagsMoreComing flag for shared connections is that this
304      * guideline applies more broadly -- any time you cancel an operation on
305      * a shared connection, you should perform all deferred UI updates for all
306      * operations sharing that connection. This is because the MoreComing flag
307      * might have been referring to events coming for the operation you canceled,
308      * which will now not be coming because the operation has been canceled.
309      *
310      * 3. Only share DNSServiceRef's created with DNSServiceCreateConnection
311      * Calling DNSServiceCreateConnection(&ref) creates a special shareable DNSServiceRef.
312      * DNSServiceRef's created by other calls like DNSServiceBrowse() or DNSServiceResolve()
313      * cannot be shared by copying them and using kDNSServiceFlagsShareConnection.
314      *
315      * 4. Don't Double-Deallocate
316      * Calling DNSServiceRefDeallocate(ref) for a particular operation's DNSServiceRef terminates
317      * just that operation. Calling DNSServiceRefDeallocate(ref) for the main shared DNSServiceRef
318      * (the parent DNSServiceRef, originally created by DNSServiceCreateConnection(&ref))
319      * automatically terminates the shared connection and all operations that were still using it.
320      * After doing this, DO NOT then attempt to deallocate any remaining subordinate DNSServiceRef's.
321      * The memory used by those subordinate DNSServiceRef's has already been freed, so any attempt
322      * to do a DNSServiceRefDeallocate (or any other operation) on them will result in accesses
323      * to freed memory, leading to crashes or other equally undesirable results.
324      *
325      * 5. Thread Safety
326      * The dns_sd.h API does not presuppose any particular threading model, and consequently
327      * does no locking of its own (which would require linking some specific threading library).
328      * If client code calls API routines on the same DNSServiceRef concurrently
329      * from multiple threads, it is the client's responsibility to use a mutext
330      * lock or take similar appropriate precautions to serialize those calls.
331      */
332 
333     kDNSServiceFlagsSuppressUnusable    = 0x8000
334     /* Placeholder definition, for future use
335      */
336     };
337 
338 /* Possible protocols for DNSServiceNATPortMappingCreate(). */
339 enum
340     {
341     kDNSServiceProtocol_IPv4 = 0x01,
342     kDNSServiceProtocol_IPv6 = 0x02,
343     /* 0x04 and 0x08 reserved for future internetwork protocols */
344 
345     kDNSServiceProtocol_UDP  = 0x10,
346     kDNSServiceProtocol_TCP  = 0x20
347     /* 0x40 and 0x80 reserved for future transport protocols, e.g. SCTP [RFC 2960]
348      * or DCCP [RFC 4340]. If future NAT gateways are created that support port
349      * mappings for these protocols, new constants will be defined here.
350      */
351     };
352 
353 /*
354  * The values for DNS Classes and Types are listed in RFC 1035, and are available
355  * on every OS in its DNS header file. Unfortunately every OS does not have the
356  * same header file containing DNS Class and Type constants, and the names of
357  * the constants are not consistent. For example, BIND 8 uses "T_A",
358  * BIND 9 uses "ns_t_a", Windows uses "DNS_TYPE_A", etc.
359  * For this reason, these constants are also listed here, so that code using
360  * the DNS-SD programming APIs can use these constants, so that the same code
361  * can compile on all our supported platforms.
362  */
363 
364 enum
365     {
366     kDNSServiceClass_IN       = 1       /* Internet */
367     };
368 
369 enum
370     {
371     kDNSServiceType_A         = 1,      /* Host address. */
372     kDNSServiceType_NS        = 2,      /* Authoritative server. */
373     kDNSServiceType_MD        = 3,      /* Mail destination. */
374     kDNSServiceType_MF        = 4,      /* Mail forwarder. */
375     kDNSServiceType_CNAME     = 5,      /* Canonical name. */
376     kDNSServiceType_SOA       = 6,      /* Start of authority zone. */
377     kDNSServiceType_MB        = 7,      /* Mailbox domain name. */
378     kDNSServiceType_MG        = 8,      /* Mail group member. */
379     kDNSServiceType_MR        = 9,      /* Mail rename name. */
380     kDNSServiceType_NULL      = 10,     /* Null resource record. */
381     kDNSServiceType_WKS       = 11,     /* Well known service. */
382     kDNSServiceType_PTR       = 12,     /* Domain name pointer. */
383     kDNSServiceType_HINFO     = 13,     /* Host information. */
384     kDNSServiceType_MINFO     = 14,     /* Mailbox information. */
385     kDNSServiceType_MX        = 15,     /* Mail routing information. */
386     kDNSServiceType_TXT       = 16,     /* One or more text strings (NOT "zero or more..."). */
387     kDNSServiceType_RP        = 17,     /* Responsible person. */
388     kDNSServiceType_AFSDB     = 18,     /* AFS cell database. */
389     kDNSServiceType_X25       = 19,     /* X_25 calling address. */
390     kDNSServiceType_ISDN      = 20,     /* ISDN calling address. */
391     kDNSServiceType_RT        = 21,     /* Router. */
392     kDNSServiceType_NSAP      = 22,     /* NSAP address. */
393     kDNSServiceType_NSAP_PTR  = 23,     /* Reverse NSAP lookup (deprecated). */
394     kDNSServiceType_SIG       = 24,     /* Security signature. */
395     kDNSServiceType_KEY       = 25,     /* Security key. */
396     kDNSServiceType_PX        = 26,     /* X.400 mail mapping. */
397     kDNSServiceType_GPOS      = 27,     /* Geographical position (withdrawn). */
398     kDNSServiceType_AAAA      = 28,     /* IPv6 Address. */
399     kDNSServiceType_LOC       = 29,     /* Location Information. */
400     kDNSServiceType_NXT       = 30,     /* Next domain (security). */
401     kDNSServiceType_EID       = 31,     /* Endpoint identifier. */
402     kDNSServiceType_NIMLOC    = 32,     /* Nimrod Locator. */
403     kDNSServiceType_SRV       = 33,     /* Server Selection. */
404     kDNSServiceType_ATMA      = 34,     /* ATM Address */
405     kDNSServiceType_NAPTR     = 35,     /* Naming Authority PoinTeR */
406     kDNSServiceType_KX        = 36,     /* Key Exchange */
407     kDNSServiceType_CERT      = 37,     /* Certification record */
408     kDNSServiceType_A6        = 38,     /* IPv6 Address (deprecated) */
409     kDNSServiceType_DNAME     = 39,     /* Non-terminal DNAME (for IPv6) */
410     kDNSServiceType_SINK      = 40,     /* Kitchen sink (experimental) */
411     kDNSServiceType_OPT       = 41,     /* EDNS0 option (meta-RR) */
412     kDNSServiceType_APL       = 42,     /* Address Prefix List */
413     kDNSServiceType_DS        = 43,     /* Delegation Signer */
414     kDNSServiceType_SSHFP     = 44,     /* SSH Key Fingerprint */
415     kDNSServiceType_IPSECKEY  = 45,     /* IPSECKEY */
416     kDNSServiceType_RRSIG     = 46,     /* RRSIG */
417     kDNSServiceType_NSEC      = 47,     /* Denial of Existence */
418     kDNSServiceType_DNSKEY    = 48,     /* DNSKEY */
419     kDNSServiceType_DHCID     = 49,     /* DHCP Client Identifier */
420     kDNSServiceType_NSEC3     = 50,     /* Hashed Authenticated Denial of Existence */
421     kDNSServiceType_NSEC3PARAM= 51,     /* Hashed Authenticated Denial of Existence */
422 
423     kDNSServiceType_HIP       = 55,     /* Host Identity Protocol */
424 
425     kDNSServiceType_SPF       = 99,     /* Sender Policy Framework for E-Mail */
426     kDNSServiceType_UINFO     = 100,    /* IANA-Reserved */
427     kDNSServiceType_UID       = 101,    /* IANA-Reserved */
428     kDNSServiceType_GID       = 102,    /* IANA-Reserved */
429     kDNSServiceType_UNSPEC    = 103,    /* IANA-Reserved */
430 
431     kDNSServiceType_TKEY      = 249,    /* Transaction key */
432     kDNSServiceType_TSIG      = 250,    /* Transaction signature. */
433     kDNSServiceType_IXFR      = 251,    /* Incremental zone transfer. */
434     kDNSServiceType_AXFR      = 252,    /* Transfer zone of authority. */
435     kDNSServiceType_MAILB     = 253,    /* Transfer mailbox records. */
436     kDNSServiceType_MAILA     = 254,    /* Transfer mail agent records. */
437     kDNSServiceType_ANY       = 255     /* Wildcard match. */
438     };
439 
440 /* possible error code values */
441 enum
442     {
443     kDNSServiceErr_NoError                   = 0,
444     kDNSServiceErr_Unknown                   = -65537,  /* 0xFFFE FFFF */
445     kDNSServiceErr_NoSuchName                = -65538,
446     kDNSServiceErr_NoMemory                  = -65539,
447     kDNSServiceErr_BadParam                  = -65540,
448     kDNSServiceErr_BadReference              = -65541,
449     kDNSServiceErr_BadState                  = -65542,
450     kDNSServiceErr_BadFlags                  = -65543,
451     kDNSServiceErr_Unsupported               = -65544,
452     kDNSServiceErr_NotInitialized            = -65545,
453     kDNSServiceErr_AlreadyRegistered         = -65547,
454     kDNSServiceErr_NameConflict              = -65548,
455     kDNSServiceErr_Invalid                   = -65549,
456     kDNSServiceErr_Firewall                  = -65550,
457     kDNSServiceErr_Incompatible              = -65551,  /* client library incompatible with daemon */
458     kDNSServiceErr_BadInterfaceIndex         = -65552,
459     kDNSServiceErr_Refused                   = -65553,
460     kDNSServiceErr_NoSuchRecord              = -65554,
461     kDNSServiceErr_NoAuth                    = -65555,
462     kDNSServiceErr_NoSuchKey                 = -65556,
463     kDNSServiceErr_NATTraversal              = -65557,
464     kDNSServiceErr_DoubleNAT                 = -65558,
465     kDNSServiceErr_BadTime                   = -65559,  /* Codes up to here existed in Tiger */
466     kDNSServiceErr_BadSig                    = -65560,
467     kDNSServiceErr_BadKey                    = -65561,
468     kDNSServiceErr_Transient                 = -65562,
469     kDNSServiceErr_ServiceNotRunning         = -65563,  /* Background daemon not running */
470     kDNSServiceErr_NATPortMappingUnsupported = -65564,  /* NAT doesn't support NAT-PMP or UPnP */
471     kDNSServiceErr_NATPortMappingDisabled    = -65565,  /* NAT supports NAT-PMP or UPnP but it's disabled by the administrator */
472     kDNSServiceErr_NoRouter                  = -65566,  /* No router currently configured (probably no network connectivity) */
473     kDNSServiceErr_PollingMode               = -65567
474 
475     /* mDNS Error codes are in the range
476      * FFFE FF00 (-65792) to FFFE FFFF (-65537) */
477     };
478 
479 /* Maximum length, in bytes, of a service name represented as a */
480 /* literal C-String, including the terminating NULL at the end. */
481 
482 #define kDNSServiceMaxServiceName 64
483 
484 /* Maximum length, in bytes, of a domain name represented as an *escaped* C-String */
485 /* including the final trailing dot, and the C-String terminating NULL at the end. */
486 
487 #define kDNSServiceMaxDomainName 1009
488 
489 /*
490  * Notes on DNS Name Escaping
491  *   -- or --
492  * "Why is kDNSServiceMaxDomainName 1009, when the maximum legal domain name is 256 bytes?"
493  *
494  * All strings used in the DNS-SD APIs are UTF-8 strings. Apart from the exceptions noted below,
495  * the APIs expect the strings to be properly escaped, using the conventional DNS escaping rules:
496  *
497  *   '\\' represents a single literal '\' in the name
498  *   '\.' represents a single literal '.' in the name
499  *   '\ddd', where ddd is a three-digit decimal value from 000 to 255,
500  *        represents a single literal byte with that value.
501  *   A bare unescaped '.' is a label separator, marking a boundary between domain and subdomain.
502  *
503  * The exceptions, that do not use escaping, are the routines where the full
504  * DNS name of a resource is broken, for convenience, into servicename/regtype/domain.
505  * In these routines, the "servicename" is NOT escaped. It does not need to be, since
506  * it is, by definition, just a single literal string. Any characters in that string
507  * represent exactly what they are. The "regtype" portion is, technically speaking,
508  * escaped, but since legal regtypes are only allowed to contain letters, digits,
509  * and hyphens, there is nothing to escape, so the issue is moot. The "domain"
510  * portion is also escaped, though most domains in use on the public Internet
511  * today, like regtypes, don't contain any characters that need to be escaped.
512  * As DNS-SD becomes more popular, rich-text domains for service discovery will
513  * become common, so software should be written to cope with domains with escaping.
514  *
515  * The servicename may be up to 63 bytes of UTF-8 text (not counting the C-String
516  * terminating NULL at the end). The regtype is of the form _service._tcp or
517  * _service._udp, where the "service" part is 1-14 characters, which may be
518  * letters, digits, or hyphens. The domain part of the three-part name may be
519  * any legal domain, providing that the resulting servicename+regtype+domain
520  * name does not exceed 256 bytes.
521  *
522  * For most software, these issues are transparent. When browsing, the discovered
523  * servicenames should simply be displayed as-is. When resolving, the discovered
524  * servicename/regtype/domain are simply passed unchanged to DNSServiceResolve().
525  * When a DNSServiceResolve() succeeds, the returned fullname is already in
526  * the correct format to pass to standard system DNS APIs such as res_query().
527  * For converting from servicename/regtype/domain to a single properly-escaped
528  * full DNS name, the helper function DNSServiceConstructFullName() is provided.
529  *
530  * The following (highly contrived) example illustrates the escaping process.
531  * Suppose you have an service called "Dr. Smith\Dr. Johnson", of type "_ftp._tcp"
532  * in subdomain "4th. Floor" of subdomain "Building 2" of domain "apple.com."
533  * The full (escaped) DNS name of this service's SRV record would be:
534  * Dr\.\032Smith\\Dr\.\032Johnson._ftp._tcp.4th\.\032Floor.Building\0322.apple.com.
535  */
536 
537 
538 /*
539  * Constants for specifying an interface index
540  *
541  * Specific interface indexes are identified via a 32-bit unsigned integer returned
542  * by the if_nametoindex() family of calls.
543  *
544  * If the client passes 0 for interface index, that means "do the right thing",
545  * which (at present) means, "if the name is in an mDNS local multicast domain
546  * (e.g. 'local.', '254.169.in-addr.arpa.', '{8,9,A,B}.E.F.ip6.arpa.') then multicast
547  * on all applicable interfaces, otherwise send via unicast to the appropriate
548  * DNS server." Normally, most clients will use 0 for interface index to
549  * automatically get the default sensible behaviour.
550  *
551  * If the client passes a positive interface index, then for multicast names that
552  * indicates to do the operation only on that one interface. For unicast names the
553  * interface index is ignored unless kDNSServiceFlagsForceMulticast is also set.
554  *
555  * If the client passes kDNSServiceInterfaceIndexLocalOnly when registering
556  * a service, then that service will be found *only* by other local clients
557  * on the same machine that are browsing using kDNSServiceInterfaceIndexLocalOnly
558  * or kDNSServiceInterfaceIndexAny.
559  * If a client has a 'private' service, accessible only to other processes
560  * running on the same machine, this allows the client to advertise that service
561  * in a way such that it does not inadvertently appear in service lists on
562  * all the other machines on the network.
563  *
564  * If the client passes kDNSServiceInterfaceIndexLocalOnly when browsing
565  * then it will find *all* records registered on that same local machine.
566  * Clients explicitly wishing to discover *only* LocalOnly services can
567  * accomplish this by inspecting the interfaceIndex of each service reported
568  * to their DNSServiceBrowseReply() callback function, and discarding those
569  * where the interface index is not kDNSServiceInterfaceIndexLocalOnly.
570  */
571 
572 #define kDNSServiceInterfaceIndexAny 0
573 #define kDNSServiceInterfaceIndexLocalOnly ((uint32_t)-1)
574 #define kDNSServiceInterfaceIndexUnicast   ((uint32_t)-2)
575 
576 typedef uint32_t DNSServiceFlags;
577 typedef uint32_t DNSServiceProtocol;
578 typedef int32_t  DNSServiceErrorType;
579 
580 
581 /*********************************************************************************************
582  *
583  * Version checking
584  *
585  *********************************************************************************************/
586 
587 /* DNSServiceGetProperty() Parameters:
588  *
589  * property:        The requested property.
590  *                  Currently the only property defined is kDNSServiceProperty_DaemonVersion.
591  *
592  * result:          Place to store result.
593  *                  For retrieving DaemonVersion, this should be the address of a uint32_t.
594  *
595  * size:            Pointer to uint32_t containing size of the result location.
596  *                  For retrieving DaemonVersion, this should be sizeof(uint32_t).
597  *                  On return the uint32_t is updated to the size of the data returned.
598  *                  For DaemonVersion, the returned size is always sizeof(uint32_t), but
599  *                  future properties could be defined which return variable-sized results.
600  *
601  * return value:    Returns kDNSServiceErr_NoError on success, or kDNSServiceErr_ServiceNotRunning
602  *                  if the daemon (or "system service" on Windows) is not running.
603  */
604 
605 DNSServiceErrorType DNSSD_API DNSServiceGetProperty
606     (
607     const char *property,  /* Requested property (i.e. kDNSServiceProperty_DaemonVersion) */
608     void       *result,    /* Pointer to place to store result */
609     uint32_t   *size       /* size of result location */
610     );
611 
612 /*
613  * When requesting kDNSServiceProperty_DaemonVersion, the result pointer must point
614  * to a 32-bit unsigned integer, and the size parameter must be set to sizeof(uint32_t).
615  *
616  * On return, the 32-bit unsigned integer contains the version number, formatted as follows:
617  *   Major part of the build number * 10000 +
618  *   minor part of the build number *   100
619  *
620  * For example, Mac OS X 10.4.9 has mDNSResponder-108.4, which would be represented as
621  * version 1080400. This allows applications to do simple greater-than and less-than comparisons:
622  * e.g. an application that requires at least mDNSResponder-108.4 can check:
623  *
624  *   if (version >= 1080400) ...
625  *
626  * Example usage:
627  *
628  * uint32_t version;
629  * uint32_t size = sizeof(version);
630  * DNSServiceErrorType err = DNSServiceGetProperty(kDNSServiceProperty_DaemonVersion, &version, &size);
631  * if (!err) printf("Bonjour version is %d.%d\n", version / 10000, version / 100 % 100);
632  */
633 
634 #define kDNSServiceProperty_DaemonVersion "DaemonVersion"
635 
636 
637 /*********************************************************************************************
638  *
639  * Unix Domain Socket access, DNSServiceRef deallocation, and data processing functions
640  *
641  *********************************************************************************************/
642 
643 /* DNSServiceRefSockFD()
644  *
645  * Access underlying Unix domain socket for an initialized DNSServiceRef.
646  * The DNS Service Discovery implementation uses this socket to communicate between the client and
647  * the mDNSResponder daemon. The application MUST NOT directly read from or write to this socket.
648  * Access to the socket is provided so that it can be used as a kqueue event source, a CFRunLoop
649  * event source, in a select() loop, etc. When the underlying event management subsystem (kqueue/
650  * select/CFRunLoop etc.) indicates to the client that data is available for reading on the
651  * socket, the client should call DNSServiceProcessResult(), which will extract the daemon's
652  * reply from the socket, and pass it to the appropriate application callback. By using a run
653  * loop or select(), results from the daemon can be processed asynchronously. Alternatively,
654  * a client can choose to fork a thread and have it loop calling "DNSServiceProcessResult(ref);"
655  * If DNSServiceProcessResult() is called when no data is available for reading on the socket, it
656  * will block until data does become available, and then process the data and return to the caller.
657  * When data arrives on the socket, the client is responsible for calling DNSServiceProcessResult(ref)
658  * in a timely fashion -- if the client allows a large backlog of data to build up the daemon
659  * may terminate the connection.
660  *
661  * sdRef:           A DNSServiceRef initialized by any of the DNSService calls.
662  *
663  * return value:    The DNSServiceRef's underlying socket descriptor, or -1 on
664  *                  error.
665  */
666 
667 int DNSSD_API DNSServiceRefSockFD(DNSServiceRef sdRef);
668 
669 
670 /* DNSServiceProcessResult()
671  *
672  * Read a reply from the daemon, calling the appropriate application callback. This call will
673  * block until the daemon's response is received. Use DNSServiceRefSockFD() in
674  * conjunction with a run loop or select() to determine the presence of a response from the
675  * server before calling this function to process the reply without blocking. Call this function
676  * at any point if it is acceptable to block until the daemon's response arrives. Note that the
677  * client is responsible for ensuring that DNSServiceProcessResult() is called whenever there is
678  * a reply from the daemon - the daemon may terminate its connection with a client that does not
679  * process the daemon's responses.
680  *
681  * sdRef:           A DNSServiceRef initialized by any of the DNSService calls
682  *                  that take a callback parameter.
683  *
684  * return value:    Returns kDNSServiceErr_NoError on success, otherwise returns
685  *                  an error code indicating the specific failure that occurred.
686  */
687 
688 DNSServiceErrorType DNSSD_API DNSServiceProcessResult(DNSServiceRef sdRef);
689 
690 
691 /* DNSServiceRefDeallocate()
692  *
693  * Terminate a connection with the daemon and free memory associated with the DNSServiceRef.
694  * Any services or records registered with this DNSServiceRef will be deregistered. Any
695  * Browse, Resolve, or Query operations called with this reference will be terminated.
696  *
697  * Note: If the reference's underlying socket is used in a run loop or select() call, it should
698  * be removed BEFORE DNSServiceRefDeallocate() is called, as this function closes the reference's
699  * socket.
700  *
701  * Note: If the reference was initialized with DNSServiceCreateConnection(), any DNSRecordRefs
702  * created via this reference will be invalidated by this call - the resource records are
703  * deregistered, and their DNSRecordRefs may not be used in subsequent functions. Similarly,
704  * if the reference was initialized with DNSServiceRegister, and an extra resource record was
705  * added to the service via DNSServiceAddRecord(), the DNSRecordRef created by the Add() call
706  * is invalidated when this function is called - the DNSRecordRef may not be used in subsequent
707  * functions.
708  *
709  * Note: This call is to be used only with the DNSServiceRef defined by this API. It is
710  * not compatible with dns_service_discovery_ref objects defined in the legacy Mach-based
711  * DNSServiceDiscovery.h API.
712  *
713  * sdRef:           A DNSServiceRef initialized by any of the DNSService calls.
714  *
715  */
716 
717 void DNSSD_API DNSServiceRefDeallocate(DNSServiceRef sdRef);
718 
719 
720 /*********************************************************************************************
721  *
722  * Domain Enumeration
723  *
724  *********************************************************************************************/
725 
726 /* DNSServiceEnumerateDomains()
727  *
728  * Asynchronously enumerate domains available for browsing and registration.
729  *
730  * The enumeration MUST be cancelled via DNSServiceRefDeallocate() when no more domains
731  * are to be found.
732  *
733  * Note that the names returned are (like all of DNS-SD) UTF-8 strings,
734  * and are escaped using standard DNS escaping rules.
735  * (See "Notes on DNS Name Escaping" earlier in this file for more details.)
736  * A graphical browser displaying a hierarchical tree-structured view should cut
737  * the names at the bare dots to yield individual labels, then de-escape each
738  * label according to the escaping rules, and then display the resulting UTF-8 text.
739  *
740  * DNSServiceDomainEnumReply Callback Parameters:
741  *
742  * sdRef:           The DNSServiceRef initialized by DNSServiceEnumerateDomains().
743  *
744  * flags:           Possible values are:
745  *                  kDNSServiceFlagsMoreComing
746  *                  kDNSServiceFlagsAdd
747  *                  kDNSServiceFlagsDefault
748  *
749  * interfaceIndex:  Specifies the interface on which the domain exists. (The index for a given
750  *                  interface is determined via the if_nametoindex() family of calls.)
751  *
752  * errorCode:       Will be kDNSServiceErr_NoError (0) on success, otherwise indicates
753  *                  the failure that occurred (other parameters are undefined if errorCode is nonzero).
754  *
755  * replyDomain:     The name of the domain.
756  *
757  * context:         The context pointer passed to DNSServiceEnumerateDomains.
758  *
759  */
760 
761 typedef void (DNSSD_API *DNSServiceDomainEnumReply)
762     (
763     DNSServiceRef                       sdRef,
764     DNSServiceFlags                     flags,
765     uint32_t                            interfaceIndex,
766     DNSServiceErrorType                 errorCode,
767     const char                          *replyDomain,
768     void                                *context
769     );
770 
771 
772 /* DNSServiceEnumerateDomains() Parameters:
773  *
774  * sdRef:           A pointer to an uninitialized DNSServiceRef. If the call succeeds
775  *                  then it initializes the DNSServiceRef, returns kDNSServiceErr_NoError,
776  *                  and the enumeration operation will run indefinitely until the client
777  *                  terminates it by passing this DNSServiceRef to DNSServiceRefDeallocate().
778  *
779  * flags:           Possible values are:
780  *                  kDNSServiceFlagsBrowseDomains to enumerate domains recommended for browsing.
781  *                  kDNSServiceFlagsRegistrationDomains to enumerate domains recommended
782  *                  for registration.
783  *
784  * interfaceIndex:  If non-zero, specifies the interface on which to look for domains.
785  *                  (the index for a given interface is determined via the if_nametoindex()
786  *                  family of calls.) Most applications will pass 0 to enumerate domains on
787  *                  all interfaces. See "Constants for specifying an interface index" for more details.
788  *
789  * callBack:        The function to be called when a domain is found or the call asynchronously
790  *                  fails.
791  *
792  * context:         An application context pointer which is passed to the callback function
793  *                  (may be NULL).
794  *
795  * return value:    Returns kDNSServiceErr_NoError on success (any subsequent, asynchronous
796  *                  errors are delivered to the callback), otherwise returns an error code indicating
797  *                  the error that occurred (the callback is not invoked and the DNSServiceRef
798  *                  is not initialized).
799  */
800 
801 DNSServiceErrorType DNSSD_API DNSServiceEnumerateDomains
802     (
803     DNSServiceRef                       *sdRef,
804     DNSServiceFlags                     flags,
805     uint32_t                            interfaceIndex,
806     DNSServiceDomainEnumReply           callBack,
807     void                                *context  /* may be NULL */
808     );
809 
810 
811 /*********************************************************************************************
812  *
813  *  Service Registration
814  *
815  *********************************************************************************************/
816 
817 /* Register a service that is discovered via Browse() and Resolve() calls.
818  *
819  * DNSServiceRegisterReply() Callback Parameters:
820  *
821  * sdRef:           The DNSServiceRef initialized by DNSServiceRegister().
822  *
823  * flags:           When a name is successfully registered, the callback will be
824  *                  invoked with the kDNSServiceFlagsAdd flag set. When Wide-Area
825  *                  DNS-SD is in use, it is possible for a single service to get
826  *                  more than one success callback (e.g. one in the "local" multicast
827  *                  DNS domain, and another in a wide-area unicast DNS domain).
828  *                  If a successfully-registered name later suffers a name conflict
829  *                  or similar problem and has to be deregistered, the callback will
830  *                  be invoked with the kDNSServiceFlagsAdd flag not set. The callback
831  *                  is *not* invoked in the case where the caller explicitly terminates
832  *                  the service registration by calling DNSServiceRefDeallocate(ref);
833  *
834  * errorCode:       Will be kDNSServiceErr_NoError on success, otherwise will
835  *                  indicate the failure that occurred (including name conflicts,
836  *                  if the kDNSServiceFlagsNoAutoRename flag was used when registering.)
837  *                  Other parameters are undefined if errorCode is nonzero.
838  *
839  * name:            The service name registered (if the application did not specify a name in
840  *                  DNSServiceRegister(), this indicates what name was automatically chosen).
841  *
842  * regtype:         The type of service registered, as it was passed to the callout.
843  *
844  * domain:          The domain on which the service was registered (if the application did not
845  *                  specify a domain in DNSServiceRegister(), this indicates the default domain
846  *                  on which the service was registered).
847  *
848  * context:         The context pointer that was passed to the callout.
849  *
850  */
851 
852 typedef void (DNSSD_API *DNSServiceRegisterReply)
853     (
854     DNSServiceRef                       sdRef,
855     DNSServiceFlags                     flags,
856     DNSServiceErrorType                 errorCode,
857     const char                          *name,
858     const char                          *regtype,
859     const char                          *domain,
860     void                                *context
861     );
862 
863 
864 /* DNSServiceRegister() Parameters:
865  *
866  * sdRef:           A pointer to an uninitialized DNSServiceRef. If the call succeeds
867  *                  then it initializes the DNSServiceRef, returns kDNSServiceErr_NoError,
868  *                  and the registration will remain active indefinitely until the client
869  *                  terminates it by passing this DNSServiceRef to DNSServiceRefDeallocate().
870  *
871  * interfaceIndex:  If non-zero, specifies the interface on which to register the service
872  *                  (the index for a given interface is determined via the if_nametoindex()
873  *                  family of calls.) Most applications will pass 0 to register on all
874  *                  available interfaces. See "Constants for specifying an interface index" for more details.
875  *
876  * flags:           Indicates the renaming behavior on name conflict (most applications
877  *                  will pass 0). See flag definitions above for details.
878  *
879  * name:            If non-NULL, specifies the service name to be registered.
880  *                  Most applications will not specify a name, in which case the computer
881  *                  name is used (this name is communicated to the client via the callback).
882  *                  If a name is specified, it must be 1-63 bytes of UTF-8 text.
883  *                  If the name is longer than 63 bytes it will be automatically truncated
884  *                  to a legal length, unless the NoAutoRename flag is set,
885  *                  in which case kDNSServiceErr_BadParam will be returned.
886  *
887  * regtype:         The service type followed by the protocol, separated by a dot
888  *                  (e.g. "_ftp._tcp"). The service type must be an underscore, followed
889  *                  by 1-14 characters, which may be letters, digits, or hyphens.
890  *                  The transport protocol must be "_tcp" or "_udp". New service types
891  *                  should be registered at <http://www.dns-sd.org/ServiceTypes.html>.
892  *
893  *                  Additional subtypes of the primary service type (where a service
894  *                  type has defined subtypes) follow the primary service type in a
895  *                  comma-separated list, with no additional spaces, e.g.
896  *                      "_primarytype._tcp,_subtype1,_subtype2,_subtype3"
897  *                  Subtypes provide a mechanism for filtered browsing: A client browsing
898  *                  for "_primarytype._tcp" will discover all instances of this type;
899  *                  a client browsing for "_primarytype._tcp,_subtype2" will discover only
900  *                  those instances that were registered with "_subtype2" in their list of
901  *                  registered subtypes.
902  *
903  *                  The subtype mechanism can be illustrated with some examples using the
904  *                  dns-sd command-line tool:
905  *
906  *                  % dns-sd -R Simple _test._tcp "" 1001 &
907  *                  % dns-sd -R Better _test._tcp,HasFeatureA "" 1002 &
908  *                  % dns-sd -R Best   _test._tcp,HasFeatureA,HasFeatureB "" 1003 &
909  *
910  *                  Now:
911  *                  % dns-sd -B _test._tcp             # will find all three services
912  *                  % dns-sd -B _test._tcp,HasFeatureA # finds "Better" and "Best"
913  *                  % dns-sd -B _test._tcp,HasFeatureB # finds only "Best"
914  *
915  * domain:          If non-NULL, specifies the domain on which to advertise the service.
916  *                  Most applications will not specify a domain, instead automatically
917  *                  registering in the default domain(s).
918  *
919  * host:            If non-NULL, specifies the SRV target host name. Most applications
920  *                  will not specify a host, instead automatically using the machine's
921  *                  default host name(s). Note that specifying a non-NULL host does NOT
922  *                  create an address record for that host - the application is responsible
923  *                  for ensuring that the appropriate address record exists, or creating it
924  *                  via DNSServiceRegisterRecord().
925  *
926  * port:            The port, in network byte order, on which the service accepts connections.
927  *                  Pass 0 for a "placeholder" service (i.e. a service that will not be discovered
928  *                  by browsing, but will cause a name conflict if another client tries to
929  *                  register that same name). Most clients will not use placeholder services.
930  *
931  * txtLen:          The length of the txtRecord, in bytes. Must be zero if the txtRecord is NULL.
932  *
933  * txtRecord:       The TXT record rdata. A non-NULL txtRecord MUST be a properly formatted DNS
934  *                  TXT record, i.e. <length byte> <data> <length byte> <data> ...
935  *                  Passing NULL for the txtRecord is allowed as a synonym for txtLen=1, txtRecord="",
936  *                  i.e. it creates a TXT record of length one containing a single empty string.
937  *                  RFC 1035 doesn't allow a TXT record to contain *zero* strings, so a single empty
938  *                  string is the smallest legal DNS TXT record.
939  *                  As with the other parameters, the DNSServiceRegister call copies the txtRecord
940  *                  data; e.g. if you allocated the storage for the txtRecord parameter with malloc()
941  *                  then you can safely free that memory right after the DNSServiceRegister call returns.
942  *
943  * callBack:        The function to be called when the registration completes or asynchronously
944  *                  fails. The client MAY pass NULL for the callback -  The client will NOT be notified
945  *                  of the default values picked on its behalf, and the client will NOT be notified of any
946  *                  asynchronous errors (e.g. out of memory errors, etc.) that may prevent the registration
947  *                  of the service. The client may NOT pass the NoAutoRename flag if the callback is NULL.
948  *                  The client may still deregister the service at any time via DNSServiceRefDeallocate().
949  *
950  * context:         An application context pointer which is passed to the callback function
951  *                  (may be NULL).
952  *
953  * return value:    Returns kDNSServiceErr_NoError on success (any subsequent, asynchronous
954  *                  errors are delivered to the callback), otherwise returns an error code indicating
955  *                  the error that occurred (the callback is never invoked and the DNSServiceRef
956  *                  is not initialized).
957  */
958 
959 DNSServiceErrorType DNSSD_API DNSServiceRegister
960     (
961     DNSServiceRef                       *sdRef,
962     DNSServiceFlags                     flags,
963     uint32_t                            interfaceIndex,
964     const char                          *name,         /* may be NULL */
965     const char                          *regtype,
966     const char                          *domain,       /* may be NULL */
967     const char                          *host,         /* may be NULL */
968     uint16_t                            port,
969     uint16_t                            txtLen,
970     const void                          *txtRecord,    /* may be NULL */
971     DNSServiceRegisterReply             callBack,      /* may be NULL */
972     void                                *context       /* may be NULL */
973     );
974 
975 
976 /* DNSServiceAddRecord()
977  *
978  * Add a record to a registered service. The name of the record will be the same as the
979  * registered service's name.
980  * The record can later be updated or deregistered by passing the RecordRef initialized
981  * by this function to DNSServiceUpdateRecord() or DNSServiceRemoveRecord().
982  *
983  * Note that the DNSServiceAddRecord/UpdateRecord/RemoveRecord are *NOT* thread-safe
984  * with respect to a single DNSServiceRef. If you plan to have multiple threads
985  * in your program simultaneously add, update, or remove records from the same
986  * DNSServiceRef, then it's the caller's responsibility to use a mutext lock
987  * or take similar appropriate precautions to serialize those calls.
988  *
989  * Parameters;
990  *
991  * sdRef:           A DNSServiceRef initialized by DNSServiceRegister().
992  *
993  * RecordRef:       A pointer to an uninitialized DNSRecordRef. Upon succesfull completion of this
994  *                  call, this ref may be passed to DNSServiceUpdateRecord() or DNSServiceRemoveRecord().
995  *                  If the above DNSServiceRef is passed to DNSServiceRefDeallocate(), RecordRef is also
996  *                  invalidated and may not be used further.
997  *
998  * flags:           Currently ignored, reserved for future use.
999  *
1000  * rrtype:          The type of the record (e.g. kDNSServiceType_TXT, kDNSServiceType_SRV, etc)
1001  *
1002  * rdlen:           The length, in bytes, of the rdata.
1003  *
1004  * rdata:           The raw rdata to be contained in the added resource record.
1005  *
1006  * ttl:             The time to live of the resource record, in seconds.
1007  *                  Most clients should pass 0 to indicate that the system should
1008  *                  select a sensible default value.
1009  *
1010  * return value:    Returns kDNSServiceErr_NoError on success, otherwise returns an
1011  *                  error code indicating the error that occurred (the RecordRef is not initialized).
1012  */
1013 
1014 DNSServiceErrorType DNSSD_API DNSServiceAddRecord
1015     (
1016     DNSServiceRef                       sdRef,
1017     DNSRecordRef                        *RecordRef,
1018     DNSServiceFlags                     flags,
1019     uint16_t                            rrtype,
1020     uint16_t                            rdlen,
1021     const void                          *rdata,
1022     uint32_t                            ttl
1023     );
1024 
1025 
1026 /* DNSServiceUpdateRecord
1027  *
1028  * Update a registered resource record. The record must either be:
1029  *   - The primary txt record of a service registered via DNSServiceRegister()
1030  *   - A record added to a registered service via DNSServiceAddRecord()
1031  *   - An individual record registered by DNSServiceRegisterRecord()
1032  *
1033  * Parameters:
1034  *
1035  * sdRef:           A DNSServiceRef that was initialized by DNSServiceRegister()
1036  *                  or DNSServiceCreateConnection().
1037  *
1038  * RecordRef:       A DNSRecordRef initialized by DNSServiceAddRecord, or NULL to update the
1039  *                  service's primary txt record.
1040  *
1041  * flags:           Currently ignored, reserved for future use.
1042  *
1043  * rdlen:           The length, in bytes, of the new rdata.
1044  *
1045  * rdata:           The new rdata to be contained in the updated resource record.
1046  *
1047  * ttl:             The time to live of the updated resource record, in seconds.
1048  *                  Most clients should pass 0 to indicate that the system should
1049  *                  select a sensible default value.
1050  *
1051  * return value:    Returns kDNSServiceErr_NoError on success, otherwise returns an
1052  *                  error code indicating the error that occurred.
1053  */
1054 
1055 DNSServiceErrorType DNSSD_API DNSServiceUpdateRecord
1056     (
1057     DNSServiceRef                       sdRef,
1058     DNSRecordRef                        RecordRef,     /* may be NULL */
1059     DNSServiceFlags                     flags,
1060     uint16_t                            rdlen,
1061     const void                          *rdata,
1062     uint32_t                            ttl
1063     );
1064 
1065 
1066 /* DNSServiceRemoveRecord
1067  *
1068  * Remove a record previously added to a service record set via DNSServiceAddRecord(), or deregister
1069  * an record registered individually via DNSServiceRegisterRecord().
1070  *
1071  * Parameters:
1072  *
1073  * sdRef:           A DNSServiceRef initialized by DNSServiceRegister() (if the
1074  *                  record being removed was registered via DNSServiceAddRecord()) or by
1075  *                  DNSServiceCreateConnection() (if the record being removed was registered via
1076  *                  DNSServiceRegisterRecord()).
1077  *
1078  * recordRef:       A DNSRecordRef initialized by a successful call to DNSServiceAddRecord()
1079  *                  or DNSServiceRegisterRecord().
1080  *
1081  * flags:           Currently ignored, reserved for future use.
1082  *
1083  * return value:    Returns kDNSServiceErr_NoError on success, otherwise returns an
1084  *                  error code indicating the error that occurred.
1085  */
1086 
1087 DNSServiceErrorType DNSSD_API DNSServiceRemoveRecord
1088     (
1089     DNSServiceRef                 sdRef,
1090     DNSRecordRef                  RecordRef,
1091     DNSServiceFlags               flags
1092     );
1093 
1094 
1095 /*********************************************************************************************
1096  *
1097  *  Service Discovery
1098  *
1099  *********************************************************************************************/
1100 
1101 /* Browse for instances of a service.
1102  *
1103  * DNSServiceBrowseReply() Parameters:
1104  *
1105  * sdRef:           The DNSServiceRef initialized by DNSServiceBrowse().
1106  *
1107  * flags:           Possible values are kDNSServiceFlagsMoreComing and kDNSServiceFlagsAdd.
1108  *                  See flag definitions for details.
1109  *
1110  * interfaceIndex:  The interface on which the service is advertised. This index should
1111  *                  be passed to DNSServiceResolve() when resolving the service.
1112  *
1113  * errorCode:       Will be kDNSServiceErr_NoError (0) on success, otherwise will
1114  *                  indicate the failure that occurred. Other parameters are undefined if
1115  *                  the errorCode is nonzero.
1116  *
1117  * serviceName:     The discovered service name. This name should be displayed to the user,
1118  *                  and stored for subsequent use in the DNSServiceResolve() call.
1119  *
1120  * regtype:         The service type, which is usually (but not always) the same as was passed
1121  *                  to DNSServiceBrowse(). One case where the discovered service type may
1122  *                  not be the same as the requested service type is when using subtypes:
1123  *                  The client may want to browse for only those ftp servers that allow
1124  *                  anonymous connections. The client will pass the string "_ftp._tcp,_anon"
1125  *                  to DNSServiceBrowse(), but the type of the service that's discovered
1126  *                  is simply "_ftp._tcp". The regtype for each discovered service instance
1127  *                  should be stored along with the name, so that it can be passed to
1128  *                  DNSServiceResolve() when the service is later resolved.
1129  *
1130  * domain:          The domain of the discovered service instance. This may or may not be the
1131  *                  same as the domain that was passed to DNSServiceBrowse(). The domain for each
1132  *                  discovered service instance should be stored along with the name, so that
1133  *                  it can be passed to DNSServiceResolve() when the service is later resolved.
1134  *
1135  * context:         The context pointer that was passed to the callout.
1136  *
1137  */
1138 
1139 typedef void (DNSSD_API *DNSServiceBrowseReply)
1140     (
1141     DNSServiceRef                       sdRef,
1142     DNSServiceFlags                     flags,
1143     uint32_t                            interfaceIndex,
1144     DNSServiceErrorType                 errorCode,
1145     const char                          *serviceName,
1146     const char                          *regtype,
1147     const char                          *replyDomain,
1148     void                                *context
1149     );
1150 
1151 
1152 /* DNSServiceBrowse() Parameters:
1153  *
1154  * sdRef:           A pointer to an uninitialized DNSServiceRef. If the call succeeds
1155  *                  then it initializes the DNSServiceRef, returns kDNSServiceErr_NoError,
1156  *                  and the browse operation will run indefinitely until the client
1157  *                  terminates it by passing this DNSServiceRef to DNSServiceRefDeallocate().
1158  *
1159  * flags:           Currently ignored, reserved for future use.
1160  *
1161  * interfaceIndex:  If non-zero, specifies the interface on which to browse for services
1162  *                  (the index for a given interface is determined via the if_nametoindex()
1163  *                  family of calls.) Most applications will pass 0 to browse on all available
1164  *                  interfaces. See "Constants for specifying an interface index" for more details.
1165  *
1166  * regtype:         The service type being browsed for followed by the protocol, separated by a
1167  *                  dot (e.g. "_ftp._tcp"). The transport protocol must be "_tcp" or "_udp".
1168  *                  A client may optionally specify a single subtype to perform filtered browsing:
1169  *                  e.g. browsing for "_primarytype._tcp,_subtype" will discover only those
1170  *                  instances of "_primarytype._tcp" that were registered specifying "_subtype"
1171  *                  in their list of registered subtypes.
1172  *
1173  * domain:          If non-NULL, specifies the domain on which to browse for services.
1174  *                  Most applications will not specify a domain, instead browsing on the
1175  *                  default domain(s).
1176  *
1177  * callBack:        The function to be called when an instance of the service being browsed for
1178  *                  is found, or if the call asynchronously fails.
1179  *
1180  * context:         An application context pointer which is passed to the callback function
1181  *                  (may be NULL).
1182  *
1183  * return value:    Returns kDNSServiceErr_NoError on success (any subsequent, asynchronous
1184  *                  errors are delivered to the callback), otherwise returns an error code indicating
1185  *                  the error that occurred (the callback is not invoked and the DNSServiceRef
1186  *                  is not initialized).
1187  */
1188 
1189 DNSServiceErrorType DNSSD_API DNSServiceBrowse
1190     (
1191     DNSServiceRef                       *sdRef,
1192     DNSServiceFlags                     flags,
1193     uint32_t                            interfaceIndex,
1194     const char                          *regtype,
1195     const char                          *domain,    /* may be NULL */
1196     DNSServiceBrowseReply               callBack,
1197     void                                *context    /* may be NULL */
1198     );
1199 
1200 
1201 /* DNSServiceResolve()
1202  *
1203  * Resolve a service name discovered via DNSServiceBrowse() to a target host name, port number, and
1204  * txt record.
1205  *
1206  * Note: Applications should NOT use DNSServiceResolve() solely for txt record monitoring - use
1207  * DNSServiceQueryRecord() instead, as it is more efficient for this task.
1208  *
1209  * Note: When the desired results have been returned, the client MUST terminate the resolve by calling
1210  * DNSServiceRefDeallocate().
1211  *
1212  * Note: DNSServiceResolve() behaves correctly for typical services that have a single SRV record
1213  * and a single TXT record. To resolve non-standard services with multiple SRV or TXT records,
1214  * DNSServiceQueryRecord() should be used.
1215  *
1216  * DNSServiceResolveReply Callback Parameters:
1217  *
1218  * sdRef:           The DNSServiceRef initialized by DNSServiceResolve().
1219  *
1220  * flags:           Possible values: kDNSServiceFlagsMoreComing
1221  *
1222  * interfaceIndex:  The interface on which the service was resolved.
1223  *
1224  * errorCode:       Will be kDNSServiceErr_NoError (0) on success, otherwise will
1225  *                  indicate the failure that occurred. Other parameters are undefined if
1226  *                  the errorCode is nonzero.
1227  *
1228  * fullname:        The full service domain name, in the form <servicename>.<protocol>.<domain>.
1229  *                  (This name is escaped following standard DNS rules, making it suitable for
1230  *                  passing to standard system DNS APIs such as res_query(), or to the
1231  *                  special-purpose functions included in this API that take fullname parameters.
1232  *                  See "Notes on DNS Name Escaping" earlier in this file for more details.)
1233  *
1234  * hosttarget:      The target hostname of the machine providing the service. This name can
1235  *                  be passed to functions like gethostbyname() to identify the host's IP address.
1236  *
1237  * port:            The port, in network byte order, on which connections are accepted for this service.
1238  *
1239  * txtLen:          The length of the txt record, in bytes.
1240  *
1241  * txtRecord:       The service's primary txt record, in standard txt record format.
1242  *
1243  * context:         The context pointer that was passed to the callout.
1244  *
1245  * NOTE: In earlier versions of this header file, the txtRecord parameter was declared "const char *"
1246  * This is incorrect, since it contains length bytes which are values in the range 0 to 255, not -128 to +127.
1247  * Depending on your compiler settings, this change may cause signed/unsigned mismatch warnings.
1248  * These should be fixed by updating your own callback function definition to match the corrected
1249  * function signature using "const unsigned char *txtRecord". Making this change may also fix inadvertent
1250  * bugs in your callback function, where it could have incorrectly interpreted a length byte with value 250
1251  * as being -6 instead, with various bad consequences ranging from incorrect operation to software crashes.
1252  * If you need to maintain portable code that will compile cleanly with both the old and new versions of
1253  * this header file, you should update your callback function definition to use the correct unsigned value,
1254  * and then in the place where you pass your callback function to DNSServiceResolve(), use a cast to eliminate
1255  * the compiler warning, e.g.:
1256  *   DNSServiceResolve(sd, flags, index, name, regtype, domain, (DNSServiceResolveReply)MyCallback, context);
1257  * This will ensure that your code compiles cleanly without warnings (and more importantly, works correctly)
1258  * with both the old header and with the new corrected version.
1259  *
1260  */
1261 
1262 typedef void (DNSSD_API *DNSServiceResolveReply)
1263     (
1264     DNSServiceRef                       sdRef,
1265     DNSServiceFlags                     flags,
1266     uint32_t                            interfaceIndex,
1267     DNSServiceErrorType                 errorCode,
1268     const char                          *fullname,
1269     const char                          *hosttarget,
1270     uint16_t                            port,
1271     uint16_t                            txtLen,
1272     const unsigned char                 *txtRecord,
1273     void                                *context
1274     );
1275 
1276 
1277 /* DNSServiceResolve() Parameters
1278  *
1279  * sdRef:           A pointer to an uninitialized DNSServiceRef. If the call succeeds
1280  *                  then it initializes the DNSServiceRef, returns kDNSServiceErr_NoError,
1281  *                  and the resolve operation will run indefinitely until the client
1282  *                  terminates it by passing this DNSServiceRef to DNSServiceRefDeallocate().
1283  *
1284  * flags:           Specifying kDNSServiceFlagsForceMulticast will cause query to be
1285  *                  performed with a link-local mDNS query, even if the name is an
1286  *                  apparently non-local name (i.e. a name not ending in ".local.")
1287  *
1288  * interfaceIndex:  The interface on which to resolve the service. If this resolve call is
1289  *                  as a result of a currently active DNSServiceBrowse() operation, then the
1290  *                  interfaceIndex should be the index reported in the DNSServiceBrowseReply
1291  *                  callback. If this resolve call is using information previously saved
1292  *                  (e.g. in a preference file) for later use, then use interfaceIndex 0, because
1293  *                  the desired service may now be reachable via a different physical interface.
1294  *                  See "Constants for specifying an interface index" for more details.
1295  *
1296  * name:            The name of the service instance to be resolved, as reported to the
1297  *                  DNSServiceBrowseReply() callback.
1298  *
1299  * regtype:         The type of the service instance to be resolved, as reported to the
1300  *                  DNSServiceBrowseReply() callback.
1301  *
1302  * domain:          The domain of the service instance to be resolved, as reported to the
1303  *                  DNSServiceBrowseReply() callback.
1304  *
1305  * callBack:        The function to be called when a result is found, or if the call
1306  *                  asynchronously fails.
1307  *
1308  * context:         An application context pointer which is passed to the callback function
1309  *                  (may be NULL).
1310  *
1311  * return value:    Returns kDNSServiceErr_NoError on success (any subsequent, asynchronous
1312  *                  errors are delivered to the callback), otherwise returns an error code indicating
1313  *                  the error that occurred (the callback is never invoked and the DNSServiceRef
1314  *                  is not initialized).
1315  */
1316 
1317 DNSServiceErrorType DNSSD_API DNSServiceResolve
1318     (
1319     DNSServiceRef                       *sdRef,
1320     DNSServiceFlags                     flags,
1321     uint32_t                            interfaceIndex,
1322     const char                          *name,
1323     const char                          *regtype,
1324     const char                          *domain,
1325     DNSServiceResolveReply              callBack,
1326     void                                *context  /* may be NULL */
1327     );
1328 
1329 
1330 /*********************************************************************************************
1331  *
1332  *  Querying Individual Specific Records
1333  *
1334  *********************************************************************************************/
1335 
1336 /* DNSServiceQueryRecord
1337  *
1338  * Query for an arbitrary DNS record.
1339  *
1340  * DNSServiceQueryRecordReply() Callback Parameters:
1341  *
1342  * sdRef:           The DNSServiceRef initialized by DNSServiceQueryRecord().
1343  *
1344  * flags:           Possible values are kDNSServiceFlagsMoreComing and
1345  *                  kDNSServiceFlagsAdd. The Add flag is NOT set for PTR records
1346  *                  with a ttl of 0, i.e. "Remove" events.
1347  *
1348  * interfaceIndex:  The interface on which the query was resolved (the index for a given
1349  *                  interface is determined via the if_nametoindex() family of calls).
1350  *                  See "Constants for specifying an interface index" for more details.
1351  *
1352  * errorCode:       Will be kDNSServiceErr_NoError on success, otherwise will
1353  *                  indicate the failure that occurred. Other parameters are undefined if
1354  *                  errorCode is nonzero.
1355  *
1356  * fullname:        The resource record's full domain name.
1357  *
1358  * rrtype:          The resource record's type (e.g. kDNSServiceType_PTR, kDNSServiceType_SRV, etc)
1359  *
1360  * rrclass:         The class of the resource record (usually kDNSServiceClass_IN).
1361  *
1362  * rdlen:           The length, in bytes, of the resource record rdata.
1363  *
1364  * rdata:           The raw rdata of the resource record.
1365  *
1366  * ttl:             If the client wishes to cache the result for performance reasons,
1367  *                  the TTL indicates how long the client may legitimately hold onto
1368  *                  this result, in seconds. After the TTL expires, the client should
1369  *                  consider the result no longer valid, and if it requires this data
1370  *                  again, it should be re-fetched with a new query. Of course, this
1371  *                  only applies to clients that cancel the asynchronous operation when
1372  *                  they get a result. Clients that leave the asynchronous operation
1373  *                  running can safely assume that the data remains valid until they
1374  *                  get another callback telling them otherwise.
1375  *
1376  * context:         The context pointer that was passed to the callout.
1377  *
1378  */
1379 
1380 typedef void (DNSSD_API *DNSServiceQueryRecordReply)
1381     (
1382     DNSServiceRef                       sdRef,
1383     DNSServiceFlags                     flags,
1384     uint32_t                            interfaceIndex,
1385     DNSServiceErrorType                 errorCode,
1386     const char                          *fullname,
1387     uint16_t                            rrtype,
1388     uint16_t                            rrclass,
1389     uint16_t                            rdlen,
1390     const void                          *rdata,
1391     uint32_t                            ttl,
1392     void                                *context
1393     );
1394 
1395 
1396 /* DNSServiceQueryRecord() Parameters:
1397  *
1398  * sdRef:           A pointer to an uninitialized DNSServiceRef. If the call succeeds
1399  *                  then it initializes the DNSServiceRef, returns kDNSServiceErr_NoError,
1400  *                  and the query operation will run indefinitely until the client
1401  *                  terminates it by passing this DNSServiceRef to DNSServiceRefDeallocate().
1402  *
1403  * flags:           kDNSServiceFlagsForceMulticast or kDNSServiceFlagsLongLivedQuery.
1404  *                  Pass kDNSServiceFlagsLongLivedQuery to create a "long-lived" unicast
1405  *                  query in a non-local domain. Without setting this flag, unicast queries
1406  *                  will be one-shot - that is, only answers available at the time of the call
1407  *                  will be returned. By setting this flag, answers (including Add and Remove
1408  *                  events) that become available after the initial call is made will generate
1409  *                  callbacks. This flag has no effect on link-local multicast queries.
1410  *
1411  * interfaceIndex:  If non-zero, specifies the interface on which to issue the query
1412  *                  (the index for a given interface is determined via the if_nametoindex()
1413  *                  family of calls.) Passing 0 causes the name to be queried for on all
1414  *                  interfaces. See "Constants for specifying an interface index" for more details.
1415  *
1416  * fullname:        The full domain name of the resource record to be queried for.
1417  *
1418  * rrtype:          The numerical type of the resource record to be queried for
1419  *                  (e.g. kDNSServiceType_PTR, kDNSServiceType_SRV, etc)
1420  *
1421  * rrclass:         The class of the resource record (usually kDNSServiceClass_IN).
1422  *
1423  * callBack:        The function to be called when a result is found, or if the call
1424  *                  asynchronously fails.
1425  *
1426  * context:         An application context pointer which is passed to the callback function
1427  *                  (may be NULL).
1428  *
1429  * return value:    Returns kDNSServiceErr_NoError on success (any subsequent, asynchronous
1430  *                  errors are delivered to the callback), otherwise returns an error code indicating
1431  *                  the error that occurred (the callback is never invoked and the DNSServiceRef
1432  *                  is not initialized).
1433  */
1434 
1435 DNSServiceErrorType DNSSD_API DNSServiceQueryRecord
1436     (
1437     DNSServiceRef                       *sdRef,
1438     DNSServiceFlags                     flags,
1439     uint32_t                            interfaceIndex,
1440     const char                          *fullname,
1441     uint16_t                            rrtype,
1442     uint16_t                            rrclass,
1443     DNSServiceQueryRecordReply          callBack,
1444     void                                *context  /* may be NULL */
1445     );
1446 
1447 
1448 /*********************************************************************************************
1449  *
1450  *  Unified lookup of both IPv4 and IPv6 addresses for a fully qualified hostname
1451  *
1452  *********************************************************************************************/
1453 
1454 /* DNSServiceGetAddrInfo
1455  *
1456  * Queries for the IP address of a hostname by using either Multicast or Unicast DNS.
1457  *
1458  * DNSServiceGetAddrInfoReply() parameters:
1459  *
1460  * sdRef:           The DNSServiceRef initialized by DNSServiceGetAddrInfo().
1461  *
1462  * flags:           Possible values are kDNSServiceFlagsMoreComing and
1463  *                  kDNSServiceFlagsAdd.
1464  *
1465  * interfaceIndex:  The interface to which the answers pertain.
1466  *
1467  * errorCode:       Will be kDNSServiceErr_NoError on success, otherwise will
1468  *                  indicate the failure that occurred.  Other parameters are
1469  *                  undefined if errorCode is nonzero.
1470  *
1471  * hostname:        The fully qualified domain name of the host to be queried for.
1472  *
1473  * address:         IPv4 or IPv6 address.
1474  *
1475  * ttl:             If the client wishes to cache the result for performance reasons,
1476  *                  the TTL indicates how long the client may legitimately hold onto
1477  *                  this result, in seconds. After the TTL expires, the client should
1478  *                  consider the result no longer valid, and if it requires this data
1479  *                  again, it should be re-fetched with a new query. Of course, this
1480  *                  only applies to clients that cancel the asynchronous operation when
1481  *                  they get a result. Clients that leave the asynchronous operation
1482  *                  running can safely assume that the data remains valid until they
1483  *                  get another callback telling them otherwise.
1484  *
1485  * context:         The context pointer that was passed to the callout.
1486  *
1487  */
1488 
1489 typedef void (DNSSD_API *DNSServiceGetAddrInfoReply)
1490     (
1491     DNSServiceRef                    sdRef,
1492     DNSServiceFlags                  flags,
1493     uint32_t                         interfaceIndex,
1494     DNSServiceErrorType              errorCode,
1495     const char                       *hostname,
1496     const struct sockaddr            *address,
1497     uint32_t                         ttl,
1498     void                             *context
1499     );
1500 
1501 
1502 /* DNSServiceGetAddrInfo() Parameters:
1503  *
1504  * sdRef:           A pointer to an uninitialized DNSServiceRef. If the call succeeds then it
1505  *                  initializes the DNSServiceRef, returns kDNSServiceErr_NoError, and the query
1506  *                  begins and will last indefinitely until the client terminates the query
1507  *                  by passing this DNSServiceRef to DNSServiceRefDeallocate().
1508  *
1509  * flags:           kDNSServiceFlagsForceMulticast or kDNSServiceFlagsLongLivedQuery.
1510  *                  Pass kDNSServiceFlagsLongLivedQuery to create a "long-lived" unicast
1511  *                  query in a non-local domain. Without setting this flag, unicast queries
1512  *                  will be one-shot - that is, only answers available at the time of the call
1513  *                  will be returned. By setting this flag, answers (including Add and Remove
1514  *                  events) that become available after the initial call is made will generate
1515  *                  callbacks. This flag has no effect on link-local multicast queries.
1516  *
1517  * interfaceIndex:  The interface on which to issue the query.  Passing 0 causes the query to be
1518  *                  sent on all active interfaces via Multicast or the primary interface via Unicast.
1519  *
1520  * protocol:        Pass in kDNSServiceProtocol_IPv4 to look up IPv4 addresses, or kDNSServiceProtocol_IPv6
1521  *                  to look up IPv6 addresses, or both to look up both kinds. If neither flag is
1522  *                  set, the system will apply an intelligent heuristic, which is (currently)
1523  *                  that it will attempt to look up both, except:
1524  *
1525  *                   * If "hostname" is a wide-area unicast DNS hostname (i.e. not a ".local." name)
1526  *                     but this host has no routable IPv6 address, then the call will not try to
1527  *                     look up IPv6 addresses for "hostname", since any addresses it found would be
1528  *                     unlikely to be of any use anyway. Similarly, if this host has no routable
1529  *                     IPv4 address, the call will not try to look up IPv4 addresses for "hostname".
1530  *
1531  *                   * If "hostname" is a link-local multicast DNS hostname (i.e. a ".local." name)
1532  *                     but this host has no IPv6 address of any kind, then it will not try to look
1533  *                     up IPv6 addresses for "hostname". Similarly, if this host has no IPv4 address
1534  *                     of any kind, the call will not try to look up IPv4 addresses for "hostname".
1535  *
1536  * hostname:        The fully qualified domain name of the host to be queried for.
1537  *
1538  * callBack:        The function to be called when the query succeeds or fails asynchronously.
1539  *
1540  * context:         An application context pointer which is passed to the callback function
1541  *                  (may be NULL).
1542  *
1543  * return value:    Returns kDNSServiceErr_NoError on success (any subsequent, asynchronous
1544  *                  errors are delivered to the callback), otherwise returns an error code indicating
1545  *                  the error that occurred.
1546  */
1547 
1548 DNSServiceErrorType DNSSD_API DNSServiceGetAddrInfo
1549     (
1550     DNSServiceRef                    *sdRef,
1551     DNSServiceFlags                  flags,
1552     uint32_t                         interfaceIndex,
1553     DNSServiceProtocol               protocol,
1554     const char                       *hostname,
1555     DNSServiceGetAddrInfoReply       callBack,
1556     void                             *context          /* may be NULL */
1557     );
1558 
1559 
1560 /*********************************************************************************************
1561  *
1562  *  Special Purpose Calls:
1563  *  DNSServiceCreateConnection(), DNSServiceRegisterRecord(), DNSServiceReconfirmRecord()
1564  *  (most applications will not use these)
1565  *
1566  *********************************************************************************************/
1567 
1568 /* DNSServiceCreateConnection()
1569  *
1570  * Create a connection to the daemon allowing efficient registration of
1571  * multiple individual records.
1572  *
1573  * Parameters:
1574  *
1575  * sdRef:           A pointer to an uninitialized DNSServiceRef. Deallocating
1576  *                  the reference (via DNSServiceRefDeallocate()) severs the
1577  *                  connection and deregisters all records registered on this connection.
1578  *
1579  * return value:    Returns kDNSServiceErr_NoError on success, otherwise returns
1580  *                  an error code indicating the specific failure that occurred (in which
1581  *                  case the DNSServiceRef is not initialized).
1582  */
1583 
1584 DNSServiceErrorType DNSSD_API DNSServiceCreateConnection(DNSServiceRef *sdRef);
1585 
1586 
1587 /* DNSServiceRegisterRecord
1588  *
1589  * Register an individual resource record on a connected DNSServiceRef.
1590  *
1591  * Note that name conflicts occurring for records registered via this call must be handled
1592  * by the client in the callback.
1593  *
1594  * DNSServiceRegisterRecordReply() parameters:
1595  *
1596  * sdRef:           The connected DNSServiceRef initialized by
1597  *                  DNSServiceCreateConnection().
1598  *
1599  * RecordRef:       The DNSRecordRef initialized by DNSServiceRegisterRecord(). If the above
1600  *                  DNSServiceRef is passed to DNSServiceRefDeallocate(), this DNSRecordRef is
1601  *                  invalidated, and may not be used further.
1602  *
1603  * flags:           Currently unused, reserved for future use.
1604  *
1605  * errorCode:       Will be kDNSServiceErr_NoError on success, otherwise will
1606  *                  indicate the failure that occurred (including name conflicts.)
1607  *                  Other parameters are undefined if errorCode is nonzero.
1608  *
1609  * context:         The context pointer that was passed to the callout.
1610  *
1611  */
1612 
1613  typedef void (DNSSD_API *DNSServiceRegisterRecordReply)
1614     (
1615     DNSServiceRef                       sdRef,
1616     DNSRecordRef                        RecordRef,
1617     DNSServiceFlags                     flags,
1618     DNSServiceErrorType                 errorCode,
1619     void                                *context
1620     );
1621 
1622 
1623 /* DNSServiceRegisterRecord() Parameters:
1624  *
1625  * sdRef:           A DNSServiceRef initialized by DNSServiceCreateConnection().
1626  *
1627  * RecordRef:       A pointer to an uninitialized DNSRecordRef. Upon succesfull completion of this
1628  *                  call, this ref may be passed to DNSServiceUpdateRecord() or DNSServiceRemoveRecord().
1629  *                  (To deregister ALL records registered on a single connected DNSServiceRef
1630  *                  and deallocate each of their corresponding DNSServiceRecordRefs, call
1631  *                  DNSServiceRefDeallocate()).
1632  *
1633  * flags:           Possible values are kDNSServiceFlagsShared or kDNSServiceFlagsUnique
1634  *                  (see flag type definitions for details).
1635  *
1636  * interfaceIndex:  If non-zero, specifies the interface on which to register the record
1637  *                  (the index for a given interface is determined via the if_nametoindex()
1638  *                  family of calls.) Passing 0 causes the record to be registered on all interfaces.
1639  *                  See "Constants for specifying an interface index" for more details.
1640  *
1641  * fullname:        The full domain name of the resource record.
1642  *
1643  * rrtype:          The numerical type of the resource record (e.g. kDNSServiceType_PTR, kDNSServiceType_SRV, etc)
1644  *
1645  * rrclass:         The class of the resource record (usually kDNSServiceClass_IN)
1646  *
1647  * rdlen:           Length, in bytes, of the rdata.
1648  *
1649  * rdata:           A pointer to the raw rdata, as it is to appear in the DNS record.
1650  *
1651  * ttl:             The time to live of the resource record, in seconds.
1652  *                  Most clients should pass 0 to indicate that the system should
1653  *                  select a sensible default value.
1654  *
1655  * callBack:        The function to be called when a result is found, or if the call
1656  *                  asynchronously fails (e.g. because of a name conflict.)
1657  *
1658  * context:         An application context pointer which is passed to the callback function
1659  *                  (may be NULL).
1660  *
1661  * return value:    Returns kDNSServiceErr_NoError on success (any subsequent, asynchronous
1662  *                  errors are delivered to the callback), otherwise returns an error code indicating
1663  *                  the error that occurred (the callback is never invoked and the DNSRecordRef is
1664  *                  not initialized).
1665  */
1666 
1667 DNSServiceErrorType DNSSD_API DNSServiceRegisterRecord
1668     (
1669     DNSServiceRef                       sdRef,
1670     DNSRecordRef                        *RecordRef,
1671     DNSServiceFlags                     flags,
1672     uint32_t                            interfaceIndex,
1673     const char                          *fullname,
1674     uint16_t                            rrtype,
1675     uint16_t                            rrclass,
1676     uint16_t                            rdlen,
1677     const void                          *rdata,
1678     uint32_t                            ttl,
1679     DNSServiceRegisterRecordReply       callBack,
1680     void                                *context    /* may be NULL */
1681     );
1682 
1683 
1684 /* DNSServiceReconfirmRecord
1685  *
1686  * Instruct the daemon to verify the validity of a resource record that appears
1687  * to be out of date (e.g. because TCP connection to a service's target failed.)
1688  * Causes the record to be flushed from the daemon's cache (as well as all other
1689  * daemons' caches on the network) if the record is determined to be invalid.
1690  * Use this routine conservatively. Reconfirming a record necessarily consumes
1691  * network bandwidth, so this should not be done indiscriminately.
1692  *
1693  * Parameters:
1694  *
1695  * flags:           Pass kDNSServiceFlagsForce to force immediate deletion of record,
1696  *                  instead of after some number of reconfirmation queries have gone unanswered.
1697  *
1698  * interfaceIndex:  Specifies the interface of the record in question.
1699  *                  The caller must specify the interface.
1700  *                  This API (by design) causes increased network traffic, so it requires
1701  *                  the caller to be precise about which record should be reconfirmed.
1702  *                  It is not possible to pass zero for the interface index to perform
1703  *                  a "wildcard" reconfirmation, where *all* matching records are reconfirmed.
1704  *
1705  * fullname:        The resource record's full domain name.
1706  *
1707  * rrtype:          The resource record's type (e.g. kDNSServiceType_PTR, kDNSServiceType_SRV, etc)
1708  *
1709  * rrclass:         The class of the resource record (usually kDNSServiceClass_IN).
1710  *
1711  * rdlen:           The length, in bytes, of the resource record rdata.
1712  *
1713  * rdata:           The raw rdata of the resource record.
1714  *
1715  */
1716 
1717 DNSServiceErrorType DNSSD_API DNSServiceReconfirmRecord
1718     (
1719     DNSServiceFlags                    flags,
1720     uint32_t                           interfaceIndex,
1721     const char                         *fullname,
1722     uint16_t                           rrtype,
1723     uint16_t                           rrclass,
1724     uint16_t                           rdlen,
1725     const void                         *rdata
1726     );
1727 
1728 
1729 /*********************************************************************************************
1730  *
1731  *  NAT Port Mapping
1732  *
1733  *********************************************************************************************/
1734 
1735 /* DNSServiceNATPortMappingCreate
1736  *
1737  * Request a port mapping in the NAT gateway, which maps a port on the local machine
1738  * to an external port on the NAT.
1739  *
1740  * The port mapping will be renewed indefinitely until the client process exits, or
1741  * explicitly terminates the port mapping request by calling DNSServiceRefDeallocate().
1742  * The client callback will be invoked, informing the client of the NAT gateway's
1743  * external IP address and the external port that has been allocated for this client.
1744  * The client should then record this external IP address and port using whatever
1745  * directory service mechanism it is using to enable peers to connect to it.
1746  * (Clients advertising services using Wide-Area DNS-SD DO NOT need to use this API
1747  * -- when a client calls DNSServiceRegister() NAT mappings are automatically created
1748  * and the external IP address and port for the service are recorded in the global DNS.
1749  * Only clients using some directory mechanism other than Wide-Area DNS-SD need to use
1750  * this API to explicitly map their own ports.)
1751  *
1752  * It's possible that the client callback could be called multiple times, for example
1753  * if the NAT gateway's IP address changes, or if a configuration change results in a
1754  * different external port being mapped for this client. Over the lifetime of any long-lived
1755  * port mapping, the client should be prepared to handle these notifications of changes
1756  * in the environment, and should update its recorded address and/or port as appropriate.
1757  *
1758  * NOTE: There are two unusual aspects of how the DNSServiceNATPortMappingCreate API works,
1759  * which were intentionally designed to help simplify client code:
1760  *
1761  *  1. It's not an error to request a NAT mapping when the machine is not behind a NAT gateway.
1762  *     In other NAT mapping APIs, if you request a NAT mapping and the machine is not behind a NAT
1763  *     gateway, then the API returns an error code -- it can't get you a NAT mapping if there's no
1764  *     NAT gateway. The DNSServiceNATPortMappingCreate API takes a different view. Working out
1765  *     whether or not you need a NAT mapping can be tricky and non-obvious, particularly on
1766  *     a machine with multiple active network interfaces. Rather than make every client recreate
1767  *     this logic for deciding whether a NAT mapping is required, the PortMapping API does that
1768  *     work for you. If the client calls the PortMapping API when the machine already has a
1769  *     routable public IP address, then instead of complaining about it and giving an error,
1770  *     the PortMapping API just invokes your callback, giving the machine's public address
1771  *     and your own port number. This means you don't need to write code to work out whether
1772  *     your client needs to call the PortMapping API -- just call it anyway, and if it wasn't
1773  *     necessary, no harm is done:
1774  *
1775  *     - If the machine already has a routable public IP address, then your callback
1776  *       will just be invoked giving your own address and port.
1777  *     - If a NAT mapping is required and obtained, then your callback will be invoked
1778  *       giving you the external address and port.
1779  *     - If a NAT mapping is required but not obtained from the local NAT gateway,
1780  *       or the machine has no network connectivity, then your callback will be
1781  *       invoked giving zero address and port.
1782  *
1783  *  2. In other NAT mapping APIs, if a laptop computer is put to sleep and woken up on a new
1784  *     network, it's the client's job to notice this, and work out whether a NAT mapping
1785  *     is required on the new network, and make a new NAT mapping request if necessary.
1786  *     The DNSServiceNATPortMappingCreate API does this for you, automatically.
1787  *     The client just needs to make one call to the PortMapping API, and its callback will
1788  *     be invoked any time the mapping state changes. This property complements point (1) above.
1789  *     If the client didn't make a NAT mapping request just because it determined that one was
1790  *     not required at that particular moment in time, the client would then have to monitor
1791  *     for network state changes to determine if a NAT port mapping later became necessary.
1792  *     By unconditionally making a NAT mapping request, even when a NAT mapping not to be
1793  *     necessary, the PortMapping API will then begin monitoring network state changes on behalf of
1794  *     the client, and if a NAT mapping later becomes necessary, it will automatically create a NAT
1795  *     mapping and inform the client with a new callback giving the new address and port information.
1796  *
1797  * DNSServiceNATPortMappingReply() parameters:
1798  *
1799  * sdRef:           The DNSServiceRef initialized by DNSServiceNATPortMappingCreate().
1800  *
1801  * flags:           Currently unused, reserved for future use.
1802  *
1803  * interfaceIndex:  The interface through which the NAT gateway is reached.
1804  *
1805  * errorCode:       Will be kDNSServiceErr_NoError on success.
1806  *                  Will be kDNSServiceErr_DoubleNAT when the NAT gateway is itself behind one or
1807  *                  more layers of NAT, in which case the other parameters have the defined values.
1808  *                  For other failures, will indicate the failure that occurred, and the other
1809  *                  parameters are undefined.
1810  *
1811  * externalAddress: Four byte IPv4 address in network byte order.
1812  *
1813  * protocol:        Will be kDNSServiceProtocol_UDP or kDNSServiceProtocol_TCP or both.
1814  *
1815  * internalPort:    The port on the local machine that was mapped.
1816  *
1817  * externalPort:    The actual external port in the NAT gateway that was mapped.
1818  *                  This is likely to be different than the requested external port.
1819  *
1820  * ttl:             The lifetime of the NAT port mapping created on the gateway.
1821  *                  This controls how quickly stale mappings will be garbage-collected
1822  *                  if the client machine crashes, suffers a power failure, is disconnected
1823  *                  from the network, or suffers some other unfortunate demise which
1824  *                  causes it to vanish without explicitly removing its NAT port mapping.
1825  *                  It's possible that the ttl value will differ from the requested ttl value.
1826  *
1827  * context:         The context pointer that was passed to the callout.
1828  *
1829  */
1830 
1831 typedef void (DNSSD_API *DNSServiceNATPortMappingReply)
1832     (
1833     DNSServiceRef                    sdRef,
1834     DNSServiceFlags                  flags,
1835     uint32_t                         interfaceIndex,
1836     DNSServiceErrorType              errorCode,
1837     uint32_t                         externalAddress,   /* four byte IPv4 address in network byte order */
1838     DNSServiceProtocol               protocol,
1839     uint16_t                         internalPort,
1840     uint16_t                         externalPort,      /* may be different than the requested port     */
1841     uint32_t                         ttl,               /* may be different than the requested ttl      */
1842     void                             *context
1843     );
1844 
1845 
1846 /* DNSServiceNATPortMappingCreate() Parameters:
1847  *
1848  * sdRef:           A pointer to an uninitialized DNSServiceRef. If the call succeeds then it
1849  *                  initializes the DNSServiceRef, returns kDNSServiceErr_NoError, and the nat
1850  *                  port mapping will last indefinitely until the client terminates the port
1851  *                  mapping request by passing this DNSServiceRef to DNSServiceRefDeallocate().
1852  *
1853  * flags:           Currently ignored, reserved for future use.
1854  *
1855  * interfaceIndex:  The interface on which to create port mappings in a NAT gateway. Passing 0 causes
1856  *                  the port mapping request to be sent on the primary interface.
1857  *
1858  * protocol:        To request a port mapping, pass in kDNSServiceProtocol_UDP, or kDNSServiceProtocol_TCP,
1859  *                  or (kDNSServiceProtocol_UDP | kDNSServiceProtocol_TCP) to map both.
1860  *                  The local listening port number must also be specified in the internalPort parameter.
1861  *                  To just discover the NAT gateway's external IP address, pass zero for protocol,
1862  *                  internalPort, externalPort and ttl.
1863  *
1864  * internalPort:    The port number in network byte order on the local machine which is listening for packets.
1865  *
1866  * externalPort:    The requested external port in network byte order in the NAT gateway that you would
1867  *                  like to map to the internal port. Pass 0 if you don't care which external port is chosen for you.
1868  *
1869  * ttl:             The requested renewal period of the NAT port mapping, in seconds.
1870  *                  If the client machine crashes, suffers a power failure, is disconnected from
1871  *                  the network, or suffers some other unfortunate demise which causes it to vanish
1872  *                  unexpectedly without explicitly removing its NAT port mappings, then the NAT gateway
1873  *                  will garbage-collect old stale NAT port mappings when their lifetime expires.
1874  *                  Requesting a short TTL causes such orphaned mappings to be garbage-collected
1875  *                  more promptly, but consumes system resources and network bandwidth with
1876  *                  frequent renewal packets to keep the mapping from expiring.
1877  *                  Requesting a long TTL is more efficient on the network, but in the event of the
1878  *                  client vanishing, stale NAT port mappings will not be garbage-collected as quickly.
1879  *                  Most clients should pass 0 to use a system-wide default value.
1880  *
1881  * callBack:        The function to be called when the port mapping request succeeds or fails asynchronously.
1882  *
1883  * context:         An application context pointer which is passed to the callback function
1884  *                  (may be NULL).
1885  *
1886  * return value:    Returns kDNSServiceErr_NoError on success (any subsequent, asynchronous
1887  *                  errors are delivered to the callback), otherwise returns an error code indicating
1888  *                  the error that occurred.
1889  *
1890  *                  If you don't actually want a port mapped, and are just calling the API
1891  *                  because you want to find out the NAT's external IP address (e.g. for UI
1892  *                  display) then pass zero for protocol, internalPort, externalPort and ttl.
1893  */
1894 
1895 DNSServiceErrorType DNSSD_API DNSServiceNATPortMappingCreate
1896     (
1897     DNSServiceRef                    *sdRef,
1898     DNSServiceFlags                  flags,
1899     uint32_t                         interfaceIndex,
1900     DNSServiceProtocol               protocol,          /* TCP and/or UDP          */
1901     uint16_t                         internalPort,      /* network byte order      */
1902     uint16_t                         externalPort,      /* network byte order      */
1903     uint32_t                         ttl,               /* time to live in seconds */
1904     DNSServiceNATPortMappingReply    callBack,
1905     void                             *context           /* may be NULL             */
1906     );
1907 
1908 
1909 /*********************************************************************************************
1910  *
1911  *  General Utility Functions
1912  *
1913  *********************************************************************************************/
1914 
1915 /* DNSServiceConstructFullName()
1916  *
1917  * Concatenate a three-part domain name (as returned by the above callbacks) into a
1918  * properly-escaped full domain name. Note that callbacks in the above functions ALREADY ESCAPE
1919  * strings where necessary.
1920  *
1921  * Parameters:
1922  *
1923  * fullName:        A pointer to a buffer that where the resulting full domain name is to be written.
1924  *                  The buffer must be kDNSServiceMaxDomainName (1009) bytes in length to
1925  *                  accommodate the longest legal domain name without buffer overrun.
1926  *
1927  * service:         The service name - any dots or backslashes must NOT be escaped.
1928  *                  May be NULL (to construct a PTR record name, e.g.
1929  *                  "_ftp._tcp.apple.com.").
1930  *
1931  * regtype:         The service type followed by the protocol, separated by a dot
1932  *                  (e.g. "_ftp._tcp").
1933  *
1934  * domain:          The domain name, e.g. "apple.com.". Literal dots or backslashes,
1935  *                  if any, must be escaped, e.g. "1st\. Floor.apple.com."
1936  *
1937  * return value:    Returns kDNSServiceErr_NoError (0) on success, kDNSServiceErr_BadParam on error.
1938  *
1939  */
1940 
1941 DNSServiceErrorType DNSSD_API DNSServiceConstructFullName
1942     (
1943     char                            *fullName,
1944     const char                      *service,      /* may be NULL */
1945     const char                      *regtype,
1946     const char                      *domain
1947     );
1948 
1949 
1950 /*********************************************************************************************
1951  *
1952  *   TXT Record Construction Functions
1953  *
1954  *********************************************************************************************/
1955 
1956 /*
1957  * A typical calling sequence for TXT record construction is something like:
1958  *
1959  * Client allocates storage for TXTRecord data (e.g. declare buffer on the stack)
1960  * TXTRecordCreate();
1961  * TXTRecordSetValue();
1962  * TXTRecordSetValue();
1963  * TXTRecordSetValue();
1964  * ...
1965  * DNSServiceRegister( ... TXTRecordGetLength(), TXTRecordGetBytesPtr() ... );
1966  * TXTRecordDeallocate();
1967  * Explicitly deallocate storage for TXTRecord data (if not allocated on the stack)
1968  */
1969 
1970 
1971 /* TXTRecordRef
1972  *
1973  * Opaque internal data type.
1974  * Note: Represents a DNS-SD TXT record.
1975  */
1976 
1977 typedef union _TXTRecordRef_t { char PrivateData[16]; char *ForceNaturalAlignment; } TXTRecordRef;
1978 
1979 
1980 /* TXTRecordCreate()
1981  *
1982  * Creates a new empty TXTRecordRef referencing the specified storage.
1983  *
1984  * If the buffer parameter is NULL, or the specified storage size is not
1985  * large enough to hold a key subsequently added using TXTRecordSetValue(),
1986  * then additional memory will be added as needed using malloc().
1987  *
1988  * On some platforms, when memory is low, malloc() may fail. In this
1989  * case, TXTRecordSetValue() will return kDNSServiceErr_NoMemory, and this
1990  * error condition will need to be handled as appropriate by the caller.
1991  *
1992  * You can avoid the need to handle this error condition if you ensure
1993  * that the storage you initially provide is large enough to hold all
1994  * the key/value pairs that are to be added to the record.
1995  * The caller can precompute the exact length required for all of the
1996  * key/value pairs to be added, or simply provide a fixed-sized buffer
1997  * known in advance to be large enough.
1998  * A no-value (key-only) key requires  (1 + key length) bytes.
1999  * A key with empty value requires     (1 + key length + 1) bytes.
2000  * A key with non-empty value requires (1 + key length + 1 + value length).
2001  * For most applications, DNS-SD TXT records are generally
2002  * less than 100 bytes, so in most cases a simple fixed-sized
2003  * 256-byte buffer will be more than sufficient.
2004  * Recommended size limits for DNS-SD TXT Records are discussed in
2005  * <http://files.dns-sd.org/draft-cheshire-dnsext-dns-sd.txt>
2006  *
2007  * Note: When passing parameters to and from these TXT record APIs,
2008  * the key name does not include the '=' character. The '=' character
2009  * is the separator between the key and value in the on-the-wire
2010  * packet format; it is not part of either the key or the value.
2011  *
2012  * txtRecord:       A pointer to an uninitialized TXTRecordRef.
2013  *
2014  * bufferLen:       The size of the storage provided in the "buffer" parameter.
2015  *
2016  * buffer:          Optional caller-supplied storage used to hold the TXTRecord data.
2017  *                  This storage must remain valid for as long as
2018  *                  the TXTRecordRef.
2019  */
2020 
2021 void DNSSD_API TXTRecordCreate
2022     (
2023     TXTRecordRef     *txtRecord,
2024     uint16_t         bufferLen,
2025     void             *buffer
2026     );
2027 
2028 
2029 /* TXTRecordDeallocate()
2030  *
2031  * Releases any resources allocated in the course of preparing a TXT Record
2032  * using TXTRecordCreate()/TXTRecordSetValue()/TXTRecordRemoveValue().
2033  * Ownership of the buffer provided in TXTRecordCreate() returns to the client.
2034  *
2035  * txtRecord:           A TXTRecordRef initialized by calling TXTRecordCreate().
2036  *
2037  */
2038 
2039 void DNSSD_API TXTRecordDeallocate
2040     (
2041     TXTRecordRef     *txtRecord
2042     );
2043 
2044 
2045 /* TXTRecordSetValue()
2046  *
2047  * Adds a key (optionally with value) to a TXTRecordRef. If the "key" already
2048  * exists in the TXTRecordRef, then the current value will be replaced with
2049  * the new value.
2050  * Keys may exist in four states with respect to a given TXT record:
2051  *  - Absent (key does not appear at all)
2052  *  - Present with no value ("key" appears alone)
2053  *  - Present with empty value ("key=" appears in TXT record)
2054  *  - Present with non-empty value ("key=value" appears in TXT record)
2055  * For more details refer to "Data Syntax for DNS-SD TXT Records" in
2056  * <http://files.dns-sd.org/draft-cheshire-dnsext-dns-sd.txt>
2057  *
2058  * txtRecord:       A TXTRecordRef initialized by calling TXTRecordCreate().
2059  *
2060  * key:             A null-terminated string which only contains printable ASCII
2061  *                  values (0x20-0x7E), excluding '=' (0x3D). Keys should be
2062  *                  9 characters or fewer (not counting the terminating null).
2063  *
2064  * valueSize:       The size of the value.
2065  *
2066  * value:           Any binary value. For values that represent
2067  *                  textual data, UTF-8 is STRONGLY recommended.
2068  *                  For values that represent textual data, valueSize
2069  *                  should NOT include the terminating null (if any)
2070  *                  at the end of the string.
2071  *                  If NULL, then "key" will be added with no value.
2072  *                  If non-NULL but valueSize is zero, then "key=" will be
2073  *                  added with empty value.
2074  *
2075  * return value:    Returns kDNSServiceErr_NoError on success.
2076  *                  Returns kDNSServiceErr_Invalid if the "key" string contains
2077  *                  illegal characters.
2078  *                  Returns kDNSServiceErr_NoMemory if adding this key would
2079  *                  exceed the available storage.
2080  */
2081 
2082 DNSServiceErrorType DNSSD_API TXTRecordSetValue
2083     (
2084     TXTRecordRef     *txtRecord,
2085     const char       *key,
2086     uint8_t          valueSize,        /* may be zero */
2087     const void       *value            /* may be NULL */
2088     );
2089 
2090 
2091 /* TXTRecordRemoveValue()
2092  *
2093  * Removes a key from a TXTRecordRef. The "key" must be an
2094  * ASCII string which exists in the TXTRecordRef.
2095  *
2096  * txtRecord:       A TXTRecordRef initialized by calling TXTRecordCreate().
2097  *
2098  * key:             A key name which exists in the TXTRecordRef.
2099  *
2100  * return value:    Returns kDNSServiceErr_NoError on success.
2101  *                  Returns kDNSServiceErr_NoSuchKey if the "key" does not
2102  *                  exist in the TXTRecordRef.
2103  */
2104 
2105 DNSServiceErrorType DNSSD_API TXTRecordRemoveValue
2106     (
2107     TXTRecordRef     *txtRecord,
2108     const char       *key
2109     );
2110 
2111 
2112 /* TXTRecordGetLength()
2113  *
2114  * Allows you to determine the length of the raw bytes within a TXTRecordRef.
2115  *
2116  * txtRecord:       A TXTRecordRef initialized by calling TXTRecordCreate().
2117  *
2118  * return value:    Returns the size of the raw bytes inside a TXTRecordRef
2119  *                  which you can pass directly to DNSServiceRegister() or
2120  *                  to DNSServiceUpdateRecord().
2121  *                  Returns 0 if the TXTRecordRef is empty.
2122  */
2123 
2124 uint16_t DNSSD_API TXTRecordGetLength
2125     (
2126     const TXTRecordRef *txtRecord
2127     );
2128 
2129 
2130 /* TXTRecordGetBytesPtr()
2131  *
2132  * Allows you to retrieve a pointer to the raw bytes within a TXTRecordRef.
2133  *
2134  * txtRecord:       A TXTRecordRef initialized by calling TXTRecordCreate().
2135  *
2136  * return value:    Returns a pointer to the raw bytes inside the TXTRecordRef
2137  *                  which you can pass directly to DNSServiceRegister() or
2138  *                  to DNSServiceUpdateRecord().
2139  */
2140 
2141 const void * DNSSD_API TXTRecordGetBytesPtr
2142     (
2143     const TXTRecordRef *txtRecord
2144     );
2145 
2146 
2147 /*********************************************************************************************
2148  *
2149  *   TXT Record Parsing Functions
2150  *
2151  *********************************************************************************************/
2152 
2153 /*
2154  * A typical calling sequence for TXT record parsing is something like:
2155  *
2156  * Receive TXT record data in DNSServiceResolve() callback
2157  * if (TXTRecordContainsKey(txtLen, txtRecord, "key")) then do something
2158  * val1ptr = TXTRecordGetValuePtr(txtLen, txtRecord, "key1", &len1);
2159  * val2ptr = TXTRecordGetValuePtr(txtLen, txtRecord, "key2", &len2);
2160  * ...
2161  * memcpy(myval1, val1ptr, len1);
2162  * memcpy(myval2, val2ptr, len2);
2163  * ...
2164  * return;
2165  *
2166  * If you wish to retain the values after return from the DNSServiceResolve()
2167  * callback, then you need to copy the data to your own storage using memcpy()
2168  * or similar, as shown in the example above.
2169  *
2170  * If for some reason you need to parse a TXT record you built yourself
2171  * using the TXT record construction functions above, then you can do
2172  * that using TXTRecordGetLength and TXTRecordGetBytesPtr calls:
2173  * TXTRecordGetValue(TXTRecordGetLength(x), TXTRecordGetBytesPtr(x), key, &len);
2174  *
2175  * Most applications only fetch keys they know about from a TXT record and
2176  * ignore the rest.
2177  * However, some debugging tools wish to fetch and display all keys.
2178  * To do that, use the TXTRecordGetCount() and TXTRecordGetItemAtIndex() calls.
2179  */
2180 
2181 /* TXTRecordContainsKey()
2182  *
2183  * Allows you to determine if a given TXT Record contains a specified key.
2184  *
2185  * txtLen:          The size of the received TXT Record.
2186  *
2187  * txtRecord:       Pointer to the received TXT Record bytes.
2188  *
2189  * key:             A null-terminated ASCII string containing the key name.
2190  *
2191  * return value:    Returns 1 if the TXT Record contains the specified key.
2192  *                  Otherwise, it returns 0.
2193  */
2194 
2195 int DNSSD_API TXTRecordContainsKey
2196     (
2197     uint16_t         txtLen,
2198     const void       *txtRecord,
2199     const char       *key
2200     );
2201 
2202 
2203 /* TXTRecordGetValuePtr()
2204  *
2205  * Allows you to retrieve the value for a given key from a TXT Record.
2206  *
2207  * txtLen:          The size of the received TXT Record
2208  *
2209  * txtRecord:       Pointer to the received TXT Record bytes.
2210  *
2211  * key:             A null-terminated ASCII string containing the key name.
2212  *
2213  * valueLen:        On output, will be set to the size of the "value" data.
2214  *
2215  * return value:    Returns NULL if the key does not exist in this TXT record,
2216  *                  or exists with no value (to differentiate between
2217  *                  these two cases use TXTRecordContainsKey()).
2218  *                  Returns pointer to location within TXT Record bytes
2219  *                  if the key exists with empty or non-empty value.
2220  *                  For empty value, valueLen will be zero.
2221  *                  For non-empty value, valueLen will be length of value data.
2222  */
2223 
2224 const void * DNSSD_API TXTRecordGetValuePtr
2225     (
2226     uint16_t         txtLen,
2227     const void       *txtRecord,
2228     const char       *key,
2229     uint8_t          *valueLen
2230     );
2231 
2232 
2233 /* TXTRecordGetCount()
2234  *
2235  * Returns the number of keys stored in the TXT Record. The count
2236  * can be used with TXTRecordGetItemAtIndex() to iterate through the keys.
2237  *
2238  * txtLen:          The size of the received TXT Record.
2239  *
2240  * txtRecord:       Pointer to the received TXT Record bytes.
2241  *
2242  * return value:    Returns the total number of keys in the TXT Record.
2243  *
2244  */
2245 
2246 uint16_t DNSSD_API TXTRecordGetCount
2247     (
2248     uint16_t         txtLen,
2249     const void       *txtRecord
2250     );
2251 
2252 
2253 /* TXTRecordGetItemAtIndex()
2254  *
2255  * Allows you to retrieve a key name and value pointer, given an index into
2256  * a TXT Record. Legal index values range from zero to TXTRecordGetCount()-1.
2257  * It's also possible to iterate through keys in a TXT record by simply
2258  * calling TXTRecordGetItemAtIndex() repeatedly, beginning with index zero
2259  * and increasing until TXTRecordGetItemAtIndex() returns kDNSServiceErr_Invalid.
2260  *
2261  * On return:
2262  * For keys with no value, *value is set to NULL and *valueLen is zero.
2263  * For keys with empty value, *value is non-NULL and *valueLen is zero.
2264  * For keys with non-empty value, *value is non-NULL and *valueLen is non-zero.
2265  *
2266  * txtLen:          The size of the received TXT Record.
2267  *
2268  * txtRecord:       Pointer to the received TXT Record bytes.
2269  *
2270  * itemIndex:       An index into the TXT Record.
2271  *
2272  * keyBufLen:       The size of the string buffer being supplied.
2273  *
2274  * key:             A string buffer used to store the key name.
2275  *                  On return, the buffer contains a null-terminated C string
2276  *                  giving the key name. DNS-SD TXT keys are usually
2277  *                  9 characters or fewer. To hold the maximum possible
2278  *                  key name, the buffer should be 256 bytes long.
2279  *
2280  * valueLen:        On output, will be set to the size of the "value" data.
2281  *
2282  * value:           On output, *value is set to point to location within TXT
2283  *                  Record bytes that holds the value data.
2284  *
2285  * return value:    Returns kDNSServiceErr_NoError on success.
2286  *                  Returns kDNSServiceErr_NoMemory if keyBufLen is too short.
2287  *                  Returns kDNSServiceErr_Invalid if index is greater than
2288  *                  TXTRecordGetCount()-1.
2289  */
2290 
2291 DNSServiceErrorType DNSSD_API TXTRecordGetItemAtIndex
2292     (
2293     uint16_t         txtLen,
2294     const void       *txtRecord,
2295     uint16_t         itemIndex,
2296     uint16_t         keyBufLen,
2297     char             *key,
2298     uint8_t          *valueLen,
2299     const void       **value
2300     );
2301 
2302 #ifdef __APPLE_API_PRIVATE
2303 
2304 /*
2305  * Mac OS X specific functionality
2306  * 3rd party clients of this API should not depend on future support or availability of this routine
2307  */
2308 
2309 /* DNSServiceSetDefaultDomainForUser()
2310  *
2311  * Set the default domain for the caller's UID. Future browse and registration
2312  * calls by this user that do not specify an explicit domain will browse and
2313  * register in this wide-area domain in addition to .local. In addition, this
2314  * domain will be returned as a Browse domain via domain enumeration calls.
2315  *
2316  * Parameters:
2317  *
2318  * flags:           Pass kDNSServiceFlagsAdd to add a domain for a user. Call without
2319  *                  this flag set to clear a previously added domain.
2320  *
2321  * domain:          The domain to be used for the caller's UID.
2322  *
2323  * return value:    Returns kDNSServiceErr_NoError on success, otherwise returns
2324  *                  an error code indicating the error that occurred.
2325  */
2326 
2327 DNSServiceErrorType DNSSD_API DNSServiceSetDefaultDomainForUser
2328     (
2329     DNSServiceFlags                    flags,
2330     const char                         *domain
2331     );
2332 
2333 /* Symbol defined to tell System Configuration Framework where to look in the Dynamic Store
2334  * for the list of PrivateDNS domains that need to be handed off to mDNSResponder
2335  * (the complete key is "State:/Network/PrivateDNS")
2336  */
2337 #define kDNSServiceCompPrivateDNS   "PrivateDNS"
2338 #define kDNSServiceCompMulticastDNS "MulticastDNS"
2339 
2340 #endif //__APPLE_API_PRIVATE
2341 
2342 #if !defined(__NetBSD__)
2343 /* Some C compiler cleverness. We can make the compiler check certain things for us,
2344  * and report errors at compile-time if anything is wrong. The usual way to do this would
2345  * be to use a run-time "if" statement or the conventional run-time "assert" mechanism, but
2346  * then you don't find out what's wrong until you run the software. This way, if the assertion
2347  * condition is false, the array size is negative, and the complier complains immediately.
2348  */
2349 
2350 struct CompileTimeAssertionChecks_DNS_SD
2351     {
2352     char assert0[(sizeof(union _TXTRecordRef_t) == 16) ? 1 : -1];
2353     };
2354 #endif
2355 
2356 #ifdef  __cplusplus
2357     }
2358 #endif
2359 
2360 #endif  /* _DNS_SD_H */
2361