xref: /titanic_52/usr/src/lib/libdns_sd/common/dns_sd.h (revision 5ffb0c9b03b5149ff4f5821a62be4a52408ada2a)
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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 /* _DNS_SD_H contains the API version number for this header file
58  * The API version defined in this header file symbol allows for compile-time
59  * checking, so that C code building with earlier versions of the header file
60  * can avoid compile errors trying to use functions that aren't even defined
61  * in those earlier versions. Similar checks may also be performed at run-time:
62  *  => weak linking -- to avoid link failures if run with an earlier
63  *     version of the library that's missing some desired symbol, or
64  *  => DNSServiceGetProperty(DaemonVersion) -- to verify whether the running daemon
65  *     ("system service" on Windows) meets some required minimum functionality level.
66  */
67 
68 #ifndef _DNS_SD_H
69 #define _DNS_SD_H 5763004
70 
71 #ifdef  __cplusplus
72 extern "C" {
73 #endif
74 
75 /* Set to 1 if libdispatch is supported
76  * Note: May also be set by project and/or Makefile
77  */
78 #ifndef _DNS_SD_LIBDISPATCH
79 #define _DNS_SD_LIBDISPATCH 0
80 #endif /* ndef _DNS_SD_LIBDISPATCH */
81 
82 /* standard calling convention under Win32 is __stdcall */
83 /* Note: When compiling Intel EFI (Extensible Firmware Interface) under MS Visual Studio, the */
84 /* _WIN32 symbol is defined by the compiler even though it's NOT compiling code for Windows32 */
85 #if defined(_WIN32) && !defined(EFI32) && !defined(EFI64)
86 #define DNSSD_API __stdcall
87 #else
88 #define DNSSD_API
89 #endif
90 
91 /* stdint.h does not exist on FreeBSD 4.x; its types are defined in sys/types.h instead */
92 #if defined(__FreeBSD__) && (__FreeBSD__ < 5)
93 #include <sys/types.h>
94 
95 /* Likewise, on Sun, standard integer types are in sys/types.h */
96 #elif defined(__sun__)
97 #include <sys/types.h>
98 
99 /* EFI does not have stdint.h, or anything else equivalent */
100 #elif defined(EFI32) || defined(EFI64) || defined(EFIX64)
101 #include "Tiano.h"
102 #if !defined(_STDINT_H_)
103 typedef UINT8 uint8_t;
104 typedef INT8 int8_t;
105 typedef UINT16 uint16_t;
106 typedef INT16 int16_t;
107 typedef UINT32 uint32_t;
108 typedef INT32 int32_t;
109 #endif
110 /* Windows has its own differences */
111 #elif defined(_WIN32)
112 #include <windows.h>
113 #define _UNUSED
114 #ifndef _MSL_STDINT_H
115 typedef UINT8 uint8_t;
116 typedef INT8 int8_t;
117 typedef UINT16 uint16_t;
118 typedef INT16 int16_t;
119 typedef UINT32 uint32_t;
120 typedef INT32 int32_t;
121 #endif
122 
123 /* All other Posix platforms use stdint.h */
124 #else
125 #include <stdint.h>
126 #endif
127 
128 #if _DNS_SD_LIBDISPATCH
129 #include <dispatch/dispatch.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  * With the exception of kDNSServiceFlagsValidate, each flag can be valid(be set)
160  * EITHER only as an input to one of the DNSService*() APIs OR only as an output
161  * (provide status) through any of the callbacks used. For example, kDNSServiceFlagsAdd
162  * can be set only as an output in the callback, whereas the kDNSServiceFlagsIncludeP2P
163  * can be set only as an input to the DNSService*() APIs. See comments on kDNSServiceFlagsValidate
164  * defined in enum below.
165  */
166 enum
167 {
168     kDNSServiceFlagsMoreComing          = 0x1,
169     /* MoreComing indicates to a callback that at least one more result is
170      * queued and will be delivered following immediately after this one.
171      * When the MoreComing flag is set, applications should not immediately
172      * update their UI, because this can result in a great deal of ugly flickering
173      * on the screen, and can waste a great deal of CPU time repeatedly updating
174      * the screen with content that is then immediately erased, over and over.
175      * Applications should wait until MoreComing is not set, and then
176      * update their UI when no more changes are imminent.
177      * When MoreComing is not set, that doesn't mean there will be no more
178      * answers EVER, just that there are no more answers immediately
179      * available right now at this instant. If more answers become available
180      * in the future they will be delivered as usual.
181      */
182 
183     kDNSServiceFlagsAdd                 = 0x2,
184     kDNSServiceFlagsDefault             = 0x4,
185     /* Flags for domain enumeration and browse/query reply callbacks.
186      * "Default" applies only to enumeration and is only valid in
187      * conjunction with "Add". An enumeration callback with the "Add"
188      * flag NOT set indicates a "Remove", i.e. the domain is no longer
189      * valid.
190      */
191 
192     kDNSServiceFlagsNoAutoRename        = 0x8,
193     /* Flag for specifying renaming behavior on name conflict when registering
194      * non-shared records. By default, name conflicts are automatically handled
195      * by renaming the service. NoAutoRename overrides this behavior - with this
196      * flag set, name conflicts will result in a callback. The NoAutorename flag
197      * is only valid if a name is explicitly specified when registering a service
198      * (i.e. the default name is not used.)
199      */
200 
201     kDNSServiceFlagsShared              = 0x10,
202     kDNSServiceFlagsUnique              = 0x20,
203     /* Flag for registering individual records on a connected
204      * DNSServiceRef. Shared indicates that there may be multiple records
205      * with this name on the network (e.g. PTR records). Unique indicates that the
206      * record's name is to be unique on the network (e.g. SRV records).
207      */
208 
209     kDNSServiceFlagsBrowseDomains       = 0x40,
210     kDNSServiceFlagsRegistrationDomains = 0x80,
211     /* Flags for specifying domain enumeration type in DNSServiceEnumerateDomains.
212      * BrowseDomains enumerates domains recommended for browsing, RegistrationDomains
213      * enumerates domains recommended for registration.
214      */
215 
216     kDNSServiceFlagsLongLivedQuery      = 0x100,
217     /* Flag for creating a long-lived unicast query for the DNSServiceQueryRecord call. */
218 
219     kDNSServiceFlagsAllowRemoteQuery    = 0x200,
220     /* Flag for creating a record for which we will answer remote queries
221      * (queries from hosts more than one hop away; hosts not directly connected to the local link).
222      */
223 
224     kDNSServiceFlagsForceMulticast      = 0x400,
225     /* Flag for signifying that a query or registration should be performed exclusively via multicast
226      * DNS, even for a name in a domain (e.g. foo.apple.com.) that would normally imply unicast DNS.
227      */
228 
229     kDNSServiceFlagsForce               = 0x800,    // This flag is deprecated.
230 
231     kDNSServiceFlagsKnownUnique         = 0x800,
232     /*
233      * Client guarantees that record names are unique, so we can skip sending out initial
234      * probe messages.  Standard name conflict resolution is still done if a conflict is discovered.
235      * Currently only valid for a DNSServiceRegister call.
236      */
237 
238     kDNSServiceFlagsReturnIntermediates = 0x1000,
239     /* Flag for returning intermediate results.
240      * For example, if a query results in an authoritative NXDomain (name does not exist)
241      * then that result is returned to the client. However the query is not implicitly
242      * cancelled -- it remains active and if the answer subsequently changes
243      * (e.g. because a VPN tunnel is subsequently established) then that positive
244      * result will still be returned to the client.
245      * Similarly, if a query results in a CNAME record, then in addition to following
246      * the CNAME referral, the intermediate CNAME result is also returned to the client.
247      * When this flag is not set, NXDomain errors are not returned, and CNAME records
248      * are followed silently without informing the client of the intermediate steps.
249      * (In earlier builds this flag was briefly calledkDNSServiceFlagsReturnCNAME)
250      */
251 
252     kDNSServiceFlagsNonBrowsable        = 0x2000,
253     /* A service registered with the NonBrowsable flag set can be resolved using
254      * DNSServiceResolve(), but will not be discoverable using DNSServiceBrowse().
255      * This is for cases where the name is actually a GUID; it is found by other means;
256      * there is no end-user benefit to browsing to find a long list of opaque GUIDs.
257      * Using the NonBrowsable flag creates SRV+TXT without the cost of also advertising
258      * an associated PTR record.
259      */
260 
261     kDNSServiceFlagsShareConnection     = 0x4000,
262     /* For efficiency, clients that perform many concurrent operations may want to use a
263      * single Unix Domain Socket connection with the background daemon, instead of having a
264      * separate connection for each independent operation. To use this mode, clients first
265      * call DNSServiceCreateConnection(&MainRef) to initialize the main DNSServiceRef.
266      * For each subsequent operation that is to share that same connection, the client copies
267      * the MainRef, and then passes the address of that copy, setting the ShareConnection flag
268      * to tell the library that this DNSServiceRef is not a typical uninitialized DNSServiceRef;
269      * it's a copy of an existing DNSServiceRef whose connection information should be reused.
270      *
271      * For example:
272      *
273      * DNSServiceErrorType error;
274      * DNSServiceRef MainRef;
275      * error = DNSServiceCreateConnection(&MainRef);
276      * if (error) ...
277      * DNSServiceRef BrowseRef = MainRef;  // Important: COPY the primary DNSServiceRef first...
278      * error = DNSServiceBrowse(&BrowseRef, kDNSServiceFlagsShareConnection, ...); // then use the copy
279      * if (error) ...
280      * ...
281      * DNSServiceRefDeallocate(BrowseRef); // Terminate the browse operation
282      * DNSServiceRefDeallocate(MainRef);   // Terminate the shared connection
283      * Also see Point 4.(Don't Double-Deallocate if the MainRef has been Deallocated) in Notes below:
284      *
285      * Notes:
286      *
287      * 1. Collective kDNSServiceFlagsMoreComing flag
288      * When callbacks are invoked using a shared DNSServiceRef, the
289      * kDNSServiceFlagsMoreComing flag applies collectively to *all* active
290      * operations sharing the same parent DNSServiceRef. If the MoreComing flag is
291      * set it means that there are more results queued on this parent DNSServiceRef,
292      * but not necessarily more results for this particular callback function.
293      * The implication of this for client programmers is that when a callback
294      * is invoked with the MoreComing flag set, the code should update its
295      * internal data structures with the new result, and set a variable indicating
296      * that its UI needs to be updated. Then, later when a callback is eventually
297      * invoked with the MoreComing flag not set, the code should update *all*
298      * stale UI elements related to that shared parent DNSServiceRef that need
299      * updating, not just the UI elements related to the particular callback
300      * that happened to be the last one to be invoked.
301      *
302      * 2. Canceling operations and kDNSServiceFlagsMoreComing
303      * Whenever you cancel any operation for which you had deferred UI updates
304      * waiting because of a kDNSServiceFlagsMoreComing flag, you should perform
305      * those deferred UI updates. This is because, after cancelling the operation,
306      * you can no longer wait for a callback *without* MoreComing set, to tell
307      * you do perform your deferred UI updates (the operation has been canceled,
308      * so there will be no more callbacks). An implication of the collective
309      * kDNSServiceFlagsMoreComing flag for shared connections is that this
310      * guideline applies more broadly -- any time you cancel an operation on
311      * a shared connection, you should perform all deferred UI updates for all
312      * operations sharing that connection. This is because the MoreComing flag
313      * might have been referring to events coming for the operation you canceled,
314      * which will now not be coming because the operation has been canceled.
315      *
316      * 3. Only share DNSServiceRef's created with DNSServiceCreateConnection
317      * Calling DNSServiceCreateConnection(&ref) creates a special shareable DNSServiceRef.
318      * DNSServiceRef's created by other calls like DNSServiceBrowse() or DNSServiceResolve()
319      * cannot be shared by copying them and using kDNSServiceFlagsShareConnection.
320      *
321      * 4. Don't Double-Deallocate if the MainRef has been Deallocated
322      * Calling DNSServiceRefDeallocate(ref) for a particular operation's DNSServiceRef terminates
323      * just that operation. Calling DNSServiceRefDeallocate(ref) for the main shared DNSServiceRef
324      * (the parent DNSServiceRef, originally created by DNSServiceCreateConnection(&ref))
325      * automatically terminates the shared connection and all operations that were still using it.
326      * After doing this, DO NOT then attempt to deallocate any remaining subordinate DNSServiceRef's.
327      * The memory used by those subordinate DNSServiceRef's has already been freed, so any attempt
328      * to do a DNSServiceRefDeallocate (or any other operation) on them will result in accesses
329      * to freed memory, leading to crashes or other equally undesirable results.
330      *
331      * 5. Thread Safety
332      * The dns_sd.h API does not presuppose any particular threading model, and consequently
333      * does no locking of its own (which would require linking some specific threading library).
334      * If client code calls API routines on the same DNSServiceRef concurrently
335      * from multiple threads, it is the client's responsibility to use a mutext
336      * lock or take similar appropriate precautions to serialize those calls.
337      */
338 
339     kDNSServiceFlagsSuppressUnusable    = 0x8000,
340     /*
341      * This flag is meaningful only in DNSServiceQueryRecord which suppresses unusable queries on the
342      * wire. If "hostname" is a wide-area unicast DNS hostname (i.e. not a ".local." name)
343      * but this host has no routable IPv6 address, then the call will not try to look up IPv6 addresses
344      * for "hostname", since any addresses it found would be unlikely to be of any use anyway. Similarly,
345      * if this host has no routable IPv4 address, the call will not try to look up IPv4 addresses for
346      * "hostname".
347      */
348 
349     kDNSServiceFlagsTimeout            = 0x10000,
350     /*
351      * When kDNServiceFlagsTimeout is passed to DNSServiceQueryRecord or DNSServiceGetAddrInfo, the query is
352      * stopped after a certain number of seconds have elapsed. The time at which the query will be stopped
353      * is determined by the system and cannot be configured by the user. The query will be stopped irrespective
354      * of whether a response was given earlier or not. When the query is stopped, the callback will be called
355      * with an error code of kDNSServiceErr_Timeout and a NULL sockaddr will be returned for DNSServiceGetAddrInfo
356      * and zero length rdata will be returned for DNSServiceQueryRecord.
357      */
358 
359     kDNSServiceFlagsIncludeP2P          = 0x20000,
360     /*
361      * Include P2P interfaces when kDNSServiceInterfaceIndexAny is specified.
362      * By default, specifying kDNSServiceInterfaceIndexAny does not include P2P interfaces.
363      */
364 
365     kDNSServiceFlagsWakeOnResolve      = 0x40000,
366     /*
367     * This flag is meaningful only in DNSServiceResolve. When set, it tries to send a magic packet
368     * to wake up the client.
369     */
370 
371     kDNSServiceFlagsBackgroundTrafficClass  = 0x80000,
372     /*
373     * This flag is meaningful for Unicast DNS queries. When set, it uses the background traffic
374     * class for packets that service the request.
375     */
376 
377     kDNSServiceFlagsIncludeAWDL      = 0x100000,
378    /*
379     * Include AWDL interface when kDNSServiceInterfaceIndexAny is specified.
380     */
381 
382     kDNSServiceFlagsValidate               = 0x200000,
383    /*
384     * This flag is meaningful in DNSServiceGetAddrInfo and DNSServiceQueryRecord. This is the ONLY flag to be valid
385     * as an input to the APIs and also an output through the callbacks in the APIs.
386     *
387     * When this flag is passed to DNSServiceQueryRecord and DNSServiceGetAddrInfo to resolve unicast names,
388     * the response  will be validated using DNSSEC. The validation results are delivered using the flags field in
389     * the callback and kDNSServiceFlagsValidate is marked in the flags to indicate that DNSSEC status is also available.
390     * When the callback is called to deliver the query results, the validation results may or may not be available.
391     * If it is not delivered along with the results, the validation status is delivered when the validation completes.
392     *
393     * When the validation results are delivered in the callback, it is indicated by marking the flags with
394     * kDNSServiceFlagsValidate and kDNSServiceFlagsAdd along with the DNSSEC status flags (described below) and a NULL
395     * sockaddr will be returned for DNSServiceGetAddrInfo and zero length rdata will be returned for DNSServiceQueryRecord.
396     * DNSSEC validation results are for the whole RRSet and not just individual records delivered in the callback. When
397     * kDNSServiceFlagsAdd is not set in the flags, applications should implicitly assume that the DNSSEC status of the
398     * RRSet that has been delivered up until that point is not valid anymore, till another callback is called with
399     * kDNSServiceFlagsAdd and kDNSServiceFlagsValidate.
400     *
401     * The following four flags indicate the status of the DNSSEC validation and marked in the flags field of the callback.
402     * When any of the four flags is set, kDNSServiceFlagsValidate will also be set. To check the validation status, the
403     * other applicable output flags should be masked. See kDNSServiceOutputFlags below.
404     */
405 
406     kDNSServiceFlagsSecure                 = 0x200010,
407    /*
408     * The response has been validated by verifying all the signaures in the response and was able to
409     * build a successful authentication chain starting from a known trust anchor.
410     */
411 
412     kDNSServiceFlagsInsecure               = 0x200020,
413    /*
414     * A chain of trust cannot be built starting from a known trust anchor to the response.
415     */
416 
417     kDNSServiceFlagsBogus                  = 0x200040,
418    /*
419     * If the response cannot be verified to be secure due to expired signatures, missing signatures etc.,
420     * then the results are considered to be bogus.
421     */
422 
423     kDNSServiceFlagsIndeterminate          = 0x200080,
424    /*
425     * There is no valid trust anchor that can be used to determine whether a response is secure or not.
426     */
427 
428     kDNSServiceFlagsUnicastResponse        = 0x400000,
429    /*
430     * Request unicast response to query.
431     */
432     kDNSServiceFlagsValidateOptional       = 0x800000,
433 
434     /*
435      * This flag is identical to kDNSServiceFlagsValidate except for the case where the response
436      * cannot be validated. If this flag is set in DNSServiceQueryRecord or DNSServiceGetAddrInfo,
437      * the DNSSEC records will be requested for validation. If they cannot be received for some reason
438      * during the validation (e.g., zone is not signed, zone is signed but cannot be traced back to
439      * root, recursive server does not understand DNSSEC etc.), then this will fallback to the default
440      * behavior where the validation will not be performed and no DNSSEC results will be provided.
441      *
442      * If the zone is signed and there is a valid path to a known trust anchor configured in the system
443      * and the application requires DNSSEC validation irrespective of the DNSSEC awareness in the current
444      * network, then this option MUST not be used. This is only intended to be used during the transition
445      * period where the different nodes participating in the DNS resolution may not understand DNSSEC or
446      * managed properly (e.g. missing DS record) but still want to be able to resolve DNS successfully.
447      */
448 
449     kDNSServiceFlagsWakeOnlyService        = 0x1000000,
450     /*
451      * This flag is meaningful only in DNSServiceRegister. When set, the service will not be registered
452      * with sleep proxy server during sleep.
453      */
454 
455     kDNSServiceFlagsThresholdOne           = 0x2000000,
456     kDNSServiceFlagsThresholdFinder        = 0x4000000,
457     kDNSServiceFlagsThresholdReached       = kDNSServiceFlagsThresholdOne,
458     /*
459      * kDNSServiceFlagsThresholdOne is meaningful only in DNSServiceBrowse. When set,
460      * the system will stop issuing browse queries on the network once the number
461      * of answers returned is one or more.  It will issue queries on the network
462      * again if the number of answers drops to zero.
463      * This flag is for Apple internal use only. Third party developers
464      * should not rely on this behavior being supported in any given software release.
465      *
466      * kDNSServiceFlagsThresholdFinder is meaningful only in DNSServiceBrowse. When set,
467      * the system will stop issuing browse queries on the network once the number
468      * of answers has reached the threshold set for Finder.
469      * It will issue queries on the network again if the number of answers drops below
470      * this threshold.
471      * This flag is for Apple internal use only. Third party developers
472      * should not rely on this behavior being supported in any given software release.
473      *
474      * When kDNSServiceFlagsThresholdReached is set in the client callback add or remove event,
475      * it indicates that the browse answer threshold has been reached and no
476      * browse requests will be generated on the network until the number of answers falls
477      * below the threshold value.  Add and remove events can still occur based
478      * on incoming Bonjour traffic observed by the system.
479      * The set of services return to the client is not guaranteed to represent the
480      * entire set of services present on the network once the threshold has been reached.
481      *
482      * Note, while kDNSServiceFlagsThresholdReached and kDNSServiceFlagsThresholdOne
483      * have the same value, there  isn't a conflict because kDNSServiceFlagsThresholdReached
484      * is only set in the callbacks and kDNSServiceFlagsThresholdOne is only set on
485      * input to a DNSServiceBrowse call.
486      */
487      kDNSServiceFlagsDenyCellular           = 0x8000000,
488     /*
489      * This flag is meaningful only for Unicast DNS queries. When set, the kernel will restrict
490      * DNS resolutions on the cellular interface for that request.
491      */
492 
493      kDNSServiceFlagsServiceIndex           = 0x10000000,
494     /*
495      * This flag is meaningful only for DNSServiceGetAddrInfo() for Unicast DNS queries.
496      * When set, DNSServiceGetAddrInfo() will interpret the "interfaceIndex" argument of the call
497      * as the "serviceIndex".
498      */
499 
500      kDNSServiceFlagsDenyExpensive          = 0x20000000
501     /*
502      * This flag is meaningful only for Unicast DNS queries. When set, the kernel will restrict
503      * DNS resolutions on interfaces defined as expensive for that request.
504      */
505 
506 };
507 
508 #define kDNSServiceOutputFlags (kDNSServiceFlagsValidate | kDNSServiceFlagsValidateOptional | kDNSServiceFlagsMoreComing | kDNSServiceFlagsAdd | kDNSServiceFlagsDefault)
509    /* All the output flags excluding the DNSSEC Status flags. Typically used to check DNSSEC Status */
510 
511 /* Possible protocol values */
512 enum
513 {
514     /* for DNSServiceGetAddrInfo() */
515     kDNSServiceProtocol_IPv4 = 0x01,
516     kDNSServiceProtocol_IPv6 = 0x02,
517     /* 0x04 and 0x08 reserved for future internetwork protocols */
518 
519     /* for DNSServiceNATPortMappingCreate() */
520     kDNSServiceProtocol_UDP  = 0x10,
521     kDNSServiceProtocol_TCP  = 0x20
522                                /* 0x40 and 0x80 reserved for future transport protocols, e.g. SCTP [RFC 2960]
523                                 * or DCCP [RFC 4340]. If future NAT gateways are created that support port
524                                 * mappings for these protocols, new constants will be defined here.
525                                 */
526 };
527 
528 /*
529  * The values for DNS Classes and Types are listed in RFC 1035, and are available
530  * on every OS in its DNS header file. Unfortunately every OS does not have the
531  * same header file containing DNS Class and Type constants, and the names of
532  * the constants are not consistent. For example, BIND 8 uses "T_A",
533  * BIND 9 uses "ns_t_a", Windows uses "DNS_TYPE_A", etc.
534  * For this reason, these constants are also listed here, so that code using
535  * the DNS-SD programming APIs can use these constants, so that the same code
536  * can compile on all our supported platforms.
537  */
538 
539 enum
540 {
541     kDNSServiceClass_IN       = 1       /* Internet */
542 };
543 
544 enum
545 {
546     kDNSServiceType_A          = 1,      /* Host address. */
547     kDNSServiceType_NS         = 2,      /* Authoritative server. */
548     kDNSServiceType_MD         = 3,      /* Mail destination. */
549     kDNSServiceType_MF         = 4,      /* Mail forwarder. */
550     kDNSServiceType_CNAME      = 5,      /* Canonical name. */
551     kDNSServiceType_SOA        = 6,      /* Start of authority zone. */
552     kDNSServiceType_MB         = 7,      /* Mailbox domain name. */
553     kDNSServiceType_MG         = 8,      /* Mail group member. */
554     kDNSServiceType_MR         = 9,      /* Mail rename name. */
555     kDNSServiceType_NULL       = 10,     /* Null resource record. */
556     kDNSServiceType_WKS        = 11,     /* Well known service. */
557     kDNSServiceType_PTR        = 12,     /* Domain name pointer. */
558     kDNSServiceType_HINFO      = 13,     /* Host information. */
559     kDNSServiceType_MINFO      = 14,     /* Mailbox information. */
560     kDNSServiceType_MX         = 15,     /* Mail routing information. */
561     kDNSServiceType_TXT        = 16,     /* One or more text strings (NOT "zero or more..."). */
562     kDNSServiceType_RP         = 17,     /* Responsible person. */
563     kDNSServiceType_AFSDB      = 18,     /* AFS cell database. */
564     kDNSServiceType_X25        = 19,     /* X_25 calling address. */
565     kDNSServiceType_ISDN       = 20,     /* ISDN calling address. */
566     kDNSServiceType_RT         = 21,     /* Router. */
567     kDNSServiceType_NSAP       = 22,     /* NSAP address. */
568     kDNSServiceType_NSAP_PTR   = 23,     /* Reverse NSAP lookup (deprecated). */
569     kDNSServiceType_SIG        = 24,     /* Security signature. */
570     kDNSServiceType_KEY        = 25,     /* Security key. */
571     kDNSServiceType_PX         = 26,     /* X.400 mail mapping. */
572     kDNSServiceType_GPOS       = 27,     /* Geographical position (withdrawn). */
573     kDNSServiceType_AAAA       = 28,     /* IPv6 Address. */
574     kDNSServiceType_LOC        = 29,     /* Location Information. */
575     kDNSServiceType_NXT        = 30,     /* Next domain (security). */
576     kDNSServiceType_EID        = 31,     /* Endpoint identifier. */
577     kDNSServiceType_NIMLOC     = 32,     /* Nimrod Locator. */
578     kDNSServiceType_SRV        = 33,     /* Server Selection. */
579     kDNSServiceType_ATMA       = 34,     /* ATM Address */
580     kDNSServiceType_NAPTR      = 35,     /* Naming Authority PoinTeR */
581     kDNSServiceType_KX         = 36,     /* Key Exchange */
582     kDNSServiceType_CERT       = 37,     /* Certification record */
583     kDNSServiceType_A6         = 38,     /* IPv6 Address (deprecated) */
584     kDNSServiceType_DNAME      = 39,     /* Non-terminal DNAME (for IPv6) */
585     kDNSServiceType_SINK       = 40,     /* Kitchen sink (experimental) */
586     kDNSServiceType_OPT        = 41,     /* EDNS0 option (meta-RR) */
587     kDNSServiceType_APL        = 42,     /* Address Prefix List */
588     kDNSServiceType_DS         = 43,     /* Delegation Signer */
589     kDNSServiceType_SSHFP      = 44,     /* SSH Key Fingerprint */
590     kDNSServiceType_IPSECKEY   = 45,     /* IPSECKEY */
591     kDNSServiceType_RRSIG      = 46,     /* RRSIG */
592     kDNSServiceType_NSEC       = 47,     /* Denial of Existence */
593     kDNSServiceType_DNSKEY     = 48,     /* DNSKEY */
594     kDNSServiceType_DHCID      = 49,     /* DHCP Client Identifier */
595     kDNSServiceType_NSEC3      = 50,     /* Hashed Authenticated Denial of Existence */
596     kDNSServiceType_NSEC3PARAM = 51,     /* Hashed Authenticated Denial of Existence */
597 
598     kDNSServiceType_HIP        = 55,     /* Host Identity Protocol */
599 
600     kDNSServiceType_SPF        = 99,     /* Sender Policy Framework for E-Mail */
601     kDNSServiceType_UINFO      = 100,    /* IANA-Reserved */
602     kDNSServiceType_UID        = 101,    /* IANA-Reserved */
603     kDNSServiceType_GID        = 102,    /* IANA-Reserved */
604     kDNSServiceType_UNSPEC     = 103,    /* IANA-Reserved */
605 
606     kDNSServiceType_TKEY       = 249,    /* Transaction key */
607     kDNSServiceType_TSIG       = 250,    /* Transaction signature. */
608     kDNSServiceType_IXFR       = 251,    /* Incremental zone transfer. */
609     kDNSServiceType_AXFR       = 252,    /* Transfer zone of authority. */
610     kDNSServiceType_MAILB      = 253,    /* Transfer mailbox records. */
611     kDNSServiceType_MAILA      = 254,    /* Transfer mail agent records. */
612     kDNSServiceType_ANY        = 255     /* Wildcard match. */
613 };
614 
615 /* possible error code values */
616 enum
617 {
618     kDNSServiceErr_NoError                   = 0,
619     kDNSServiceErr_Unknown                   = -65537,  /* 0xFFFE FFFF */
620     kDNSServiceErr_NoSuchName                = -65538,
621     kDNSServiceErr_NoMemory                  = -65539,
622     kDNSServiceErr_BadParam                  = -65540,
623     kDNSServiceErr_BadReference              = -65541,
624     kDNSServiceErr_BadState                  = -65542,
625     kDNSServiceErr_BadFlags                  = -65543,
626     kDNSServiceErr_Unsupported               = -65544,
627     kDNSServiceErr_NotInitialized            = -65545,
628     kDNSServiceErr_AlreadyRegistered         = -65547,
629     kDNSServiceErr_NameConflict              = -65548,
630     kDNSServiceErr_Invalid                   = -65549,
631     kDNSServiceErr_Firewall                  = -65550,
632     kDNSServiceErr_Incompatible              = -65551,  /* client library incompatible with daemon */
633     kDNSServiceErr_BadInterfaceIndex         = -65552,
634     kDNSServiceErr_Refused                   = -65553,
635     kDNSServiceErr_NoSuchRecord              = -65554,
636     kDNSServiceErr_NoAuth                    = -65555,
637     kDNSServiceErr_NoSuchKey                 = -65556,
638     kDNSServiceErr_NATTraversal              = -65557,
639     kDNSServiceErr_DoubleNAT                 = -65558,
640     kDNSServiceErr_BadTime                   = -65559,  /* Codes up to here existed in Tiger */
641     kDNSServiceErr_BadSig                    = -65560,
642     kDNSServiceErr_BadKey                    = -65561,
643     kDNSServiceErr_Transient                 = -65562,
644     kDNSServiceErr_ServiceNotRunning         = -65563,  /* Background daemon not running */
645     kDNSServiceErr_NATPortMappingUnsupported = -65564,  /* NAT doesn't support PCP, NAT-PMP or UPnP */
646     kDNSServiceErr_NATPortMappingDisabled    = -65565,  /* NAT supports PCP, NAT-PMP or UPnP, but it's disabled by the administrator */
647     kDNSServiceErr_NoRouter                  = -65566,  /* No router currently configured (probably no network connectivity) */
648     kDNSServiceErr_PollingMode               = -65567,
649     kDNSServiceErr_Timeout                   = -65568
650 
651                                                /* mDNS Error codes are in the range
652                                                 * FFFE FF00 (-65792) to FFFE FFFF (-65537) */
653 };
654 
655 /* Maximum length, in bytes, of a service name represented as a */
656 /* literal C-String, including the terminating NULL at the end. */
657 
658 #define kDNSServiceMaxServiceName 64
659 
660 /* Maximum length, in bytes, of a domain name represented as an *escaped* C-String */
661 /* including the final trailing dot, and the C-String terminating NULL at the end. */
662 
663 #define kDNSServiceMaxDomainName 1009
664 
665 /*
666  * Notes on DNS Name Escaping
667  *   -- or --
668  * "Why is kDNSServiceMaxDomainName 1009, when the maximum legal domain name is 256 bytes?"
669  *
670  * All strings used in the DNS-SD APIs are UTF-8 strings. Apart from the exceptions noted below,
671  * the APIs expect the strings to be properly escaped, using the conventional DNS escaping rules:
672  *
673  *   '\\' represents a single literal '\' in the name
674  *   '\.' represents a single literal '.' in the name
675  *   '\ddd', where ddd is a three-digit decimal value from 000 to 255,
676  *        represents a single literal byte with that value.
677  *   A bare unescaped '.' is a label separator, marking a boundary between domain and subdomain.
678  *
679  * The exceptions, that do not use escaping, are the routines where the full
680  * DNS name of a resource is broken, for convenience, into servicename/regtype/domain.
681  * In these routines, the "servicename" is NOT escaped. It does not need to be, since
682  * it is, by definition, just a single literal string. Any characters in that string
683  * represent exactly what they are. The "regtype" portion is, technically speaking,
684  * escaped, but since legal regtypes are only allowed to contain letters, digits,
685  * and hyphens, there is nothing to escape, so the issue is moot. The "domain"
686  * portion is also escaped, though most domains in use on the public Internet
687  * today, like regtypes, don't contain any characters that need to be escaped.
688  * As DNS-SD becomes more popular, rich-text domains for service discovery will
689  * become common, so software should be written to cope with domains with escaping.
690  *
691  * The servicename may be up to 63 bytes of UTF-8 text (not counting the C-String
692  * terminating NULL at the end). The regtype is of the form _service._tcp or
693  * _service._udp, where the "service" part is 1-15 characters, which may be
694  * letters, digits, or hyphens. The domain part of the three-part name may be
695  * any legal domain, providing that the resulting servicename+regtype+domain
696  * name does not exceed 256 bytes.
697  *
698  * For most software, these issues are transparent. When browsing, the discovered
699  * servicenames should simply be displayed as-is. When resolving, the discovered
700  * servicename/regtype/domain are simply passed unchanged to DNSServiceResolve().
701  * When a DNSServiceResolve() succeeds, the returned fullname is already in
702  * the correct format to pass to standard system DNS APIs such as res_query().
703  * For converting from servicename/regtype/domain to a single properly-escaped
704  * full DNS name, the helper function DNSServiceConstructFullName() is provided.
705  *
706  * The following (highly contrived) example illustrates the escaping process.
707  * Suppose you have an service called "Dr. Smith\Dr. Johnson", of type "_ftp._tcp"
708  * in subdomain "4th. Floor" of subdomain "Building 2" of domain "apple.com."
709  * The full (escaped) DNS name of this service's SRV record would be:
710  * Dr\.\032Smith\\Dr\.\032Johnson._ftp._tcp.4th\.\032Floor.Building\0322.apple.com.
711  */
712 
713 
714 /*
715  * Constants for specifying an interface index
716  *
717  * Specific interface indexes are identified via a 32-bit unsigned integer returned
718  * by the if_nametoindex() family of calls.
719  *
720  * If the client passes 0 for interface index, that means "do the right thing",
721  * which (at present) means, "if the name is in an mDNS local multicast domain
722  * (e.g. 'local.', '254.169.in-addr.arpa.', '{8,9,A,B}.E.F.ip6.arpa.') then multicast
723  * on all applicable interfaces, otherwise send via unicast to the appropriate
724  * DNS server." Normally, most clients will use 0 for interface index to
725  * automatically get the default sensible behaviour.
726  *
727  * If the client passes a positive interface index, then for multicast names that
728  * indicates to do the operation only on that one interface. For unicast names the
729  * interface index is ignored unless kDNSServiceFlagsForceMulticast is also set.
730  *
731  * If the client passes kDNSServiceInterfaceIndexLocalOnly when registering
732  * a service, then that service will be found *only* by other local clients
733  * on the same machine that are browsing using kDNSServiceInterfaceIndexLocalOnly
734  * or kDNSServiceInterfaceIndexAny.
735  * If a client has a 'private' service, accessible only to other processes
736  * running on the same machine, this allows the client to advertise that service
737  * in a way such that it does not inadvertently appear in service lists on
738  * all the other machines on the network.
739  *
740  * If the client passes kDNSServiceInterfaceIndexLocalOnly when browsing
741  * then it will find *all* records registered on that same local machine.
742  * Clients explicitly wishing to discover *only* LocalOnly services can
743  * accomplish this by inspecting the interfaceIndex of each service reported
744  * to their DNSServiceBrowseReply() callback function, and discarding those
745  * where the interface index is not kDNSServiceInterfaceIndexLocalOnly.
746  *
747  * kDNSServiceInterfaceIndexP2P is meaningful only in Browse, QueryRecord, Register,
748  * and Resolve operations. It should not be used in other DNSService APIs.
749  *
750  * - If kDNSServiceInterfaceIndexP2P is passed to DNSServiceBrowse or
751  *   DNSServiceQueryRecord, it restricts the operation to P2P.
752  *
753  * - If kDNSServiceInterfaceIndexP2P is passed to DNSServiceRegister, it is
754  *   mapped internally to kDNSServiceInterfaceIndexAny with the kDNSServiceFlagsIncludeP2P
755  *   set.
756  *
757  * - If kDNSServiceInterfaceIndexP2P is passed to DNSServiceResolve, it is
758  *   mapped internally to kDNSServiceInterfaceIndexAny with the kDNSServiceFlagsIncludeP2P
759  *   set, because resolving a P2P service may create and/or enable an interface whose
760  *   index is not known a priori. The resolve callback will indicate the index of the
761  *   interface via which the service can be accessed.
762  *
763  * If applications pass kDNSServiceInterfaceIndexAny to DNSServiceBrowse
764  * or DNSServiceQueryRecord, they must set the kDNSServiceFlagsIncludeP2P flag
765  * to include P2P. In this case, if a service instance or the record being queried
766  * is found over P2P, the resulting ADD event will indicate kDNSServiceInterfaceIndexP2P
767  * as the interface index.
768  */
769 
770 #define kDNSServiceInterfaceIndexAny 0
771 #define kDNSServiceInterfaceIndexLocalOnly ((uint32_t)-1)
772 #define kDNSServiceInterfaceIndexUnicast   ((uint32_t)-2)
773 #define kDNSServiceInterfaceIndexP2P       ((uint32_t)-3)
774 
775 typedef uint32_t DNSServiceFlags;
776 typedef uint32_t DNSServiceProtocol;
777 typedef int32_t DNSServiceErrorType;
778 
779 
780 /*********************************************************************************************
781 *
782 * Version checking
783 *
784 *********************************************************************************************/
785 
786 /* DNSServiceGetProperty() Parameters:
787  *
788  * property:        The requested property.
789  *                  Currently the only property defined is kDNSServiceProperty_DaemonVersion.
790  *
791  * result:          Place to store result.
792  *                  For retrieving DaemonVersion, this should be the address of a uint32_t.
793  *
794  * size:            Pointer to uint32_t containing size of the result location.
795  *                  For retrieving DaemonVersion, this should be sizeof(uint32_t).
796  *                  On return the uint32_t is updated to the size of the data returned.
797  *                  For DaemonVersion, the returned size is always sizeof(uint32_t), but
798  *                  future properties could be defined which return variable-sized results.
799  *
800  * return value:    Returns kDNSServiceErr_NoError on success, or kDNSServiceErr_ServiceNotRunning
801  *                  if the daemon (or "system service" on Windows) is not running.
802  */
803 
804 DNSServiceErrorType DNSSD_API DNSServiceGetProperty
805 (
806     const char *property,  /* Requested property (i.e. kDNSServiceProperty_DaemonVersion) */
807     void       *result,    /* Pointer to place to store result */
808     uint32_t   *size       /* size of result location */
809 );
810 
811 /*
812  * When requesting kDNSServiceProperty_DaemonVersion, the result pointer must point
813  * to a 32-bit unsigned integer, and the size parameter must be set to sizeof(uint32_t).
814  *
815  * On return, the 32-bit unsigned integer contains the API version number
816  *
817  * For example, Mac OS X 10.4.9 has API version 1080400.
818  * This allows applications to do simple greater-than and less-than comparisons:
819  * e.g. an application that requires at least API version 1080400 can check:
820  *   if (version >= 1080400) ...
821  *
822  * Example usage:
823  * uint32_t version;
824  * uint32_t size = sizeof(version);
825  * DNSServiceErrorType err = DNSServiceGetProperty(kDNSServiceProperty_DaemonVersion, &version, &size);
826  * if (!err) printf("DNS_SD API version is %d.%d\n", version / 10000, version / 100 % 100);
827  */
828 
829 #define kDNSServiceProperty_DaemonVersion "DaemonVersion"
830 
831 
832 // Map the source port of the local UDP socket that was opened for sending the DNS query
833 // to the process ID of the application that triggered the DNS resolution.
834 //
835 /* DNSServiceGetPID() Parameters:
836  *
837  * srcport:         Source port (in network byte order) of the UDP socket that was created by
838  *                  the daemon to send the DNS query on the wire.
839  *
840  * pid:             Process ID of the application that started the name resolution which triggered
841  *                  the daemon to send the query on the wire. The value can be -1 if the srcport
842  *                  cannot be mapped.
843  *
844  * return value:    Returns kDNSServiceErr_NoError on success, or kDNSServiceErr_ServiceNotRunning
845  *                  if the daemon is not running. The value of the pid is undefined if the return
846  *                  value has error.
847  */
848 DNSServiceErrorType DNSSD_API DNSServiceGetPID
849 (
850     uint16_t srcport,
851     int32_t *pid
852 );
853 
854 /*********************************************************************************************
855 *
856 * Unix Domain Socket access, DNSServiceRef deallocation, and data processing functions
857 *
858 *********************************************************************************************/
859 
860 /* DNSServiceRefSockFD()
861  *
862  * Access underlying Unix domain socket for an initialized DNSServiceRef.
863  * The DNS Service Discovery implementation uses this socket to communicate between the client and
864  * the daemon. The application MUST NOT directly read from or write to this socket.
865  * Access to the socket is provided so that it can be used as a kqueue event source, a CFRunLoop
866  * event source, in a select() loop, etc. When the underlying event management subsystem (kqueue/
867  * select/CFRunLoop etc.) indicates to the client that data is available for reading on the
868  * socket, the client should call DNSServiceProcessResult(), which will extract the daemon's
869  * reply from the socket, and pass it to the appropriate application callback. By using a run
870  * loop or select(), results from the daemon can be processed asynchronously. Alternatively,
871  * a client can choose to fork a thread and have it loop calling "DNSServiceProcessResult(ref);"
872  * If DNSServiceProcessResult() is called when no data is available for reading on the socket, it
873  * will block until data does become available, and then process the data and return to the caller.
874  * The application is reponsible for checking the return value of DNSServiceProcessResult() to determine
875  * if the socket is valid and if it should continue to process data on the socket.
876  * When data arrives on the socket, the client is responsible for calling DNSServiceProcessResult(ref)
877  * in a timely fashion -- if the client allows a large backlog of data to build up the daemon
878  * may terminate the connection.
879  *
880  * sdRef:           A DNSServiceRef initialized by any of the DNSService calls.
881  *
882  * return value:    The DNSServiceRef's underlying socket descriptor, or -1 on
883  *                  error.
884  */
885 
886 int DNSSD_API DNSServiceRefSockFD(DNSServiceRef sdRef);
887 
888 
889 /* DNSServiceProcessResult()
890  *
891  * Read a reply from the daemon, calling the appropriate application callback. This call will
892  * block until the daemon's response is received. Use DNSServiceRefSockFD() in
893  * conjunction with a run loop or select() to determine the presence of a response from the
894  * server before calling this function to process the reply without blocking. Call this function
895  * at any point if it is acceptable to block until the daemon's response arrives. Note that the
896  * client is responsible for ensuring that DNSServiceProcessResult() is called whenever there is
897  * a reply from the daemon - the daemon may terminate its connection with a client that does not
898  * process the daemon's responses.
899  *
900  * sdRef:           A DNSServiceRef initialized by any of the DNSService calls
901  *                  that take a callback parameter.
902  *
903  * return value:    Returns kDNSServiceErr_NoError on success, otherwise returns
904  *                  an error code indicating the specific failure that occurred.
905  */
906 
907 DNSServiceErrorType DNSSD_API DNSServiceProcessResult(DNSServiceRef sdRef);
908 
909 
910 /* DNSServiceRefDeallocate()
911  *
912  * Terminate a connection with the daemon and free memory associated with the DNSServiceRef.
913  * Any services or records registered with this DNSServiceRef will be deregistered. Any
914  * Browse, Resolve, or Query operations called with this reference will be terminated.
915  *
916  * Note: If the reference's underlying socket is used in a run loop or select() call, it should
917  * be removed BEFORE DNSServiceRefDeallocate() is called, as this function closes the reference's
918  * socket.
919  *
920  * Note: If the reference was initialized with DNSServiceCreateConnection(), any DNSRecordRefs
921  * created via this reference will be invalidated by this call - the resource records are
922  * deregistered, and their DNSRecordRefs may not be used in subsequent functions. Similarly,
923  * if the reference was initialized with DNSServiceRegister, and an extra resource record was
924  * added to the service via DNSServiceAddRecord(), the DNSRecordRef created by the Add() call
925  * is invalidated when this function is called - the DNSRecordRef may not be used in subsequent
926  * functions.
927  *
928  * Note: This call is to be used only with the DNSServiceRef defined by this API.
929  *
930  * sdRef:           A DNSServiceRef initialized by any of the DNSService calls.
931  *
932  */
933 
934 void DNSSD_API DNSServiceRefDeallocate(DNSServiceRef sdRef);
935 
936 
937 /*********************************************************************************************
938 *
939 * Domain Enumeration
940 *
941 *********************************************************************************************/
942 
943 /* DNSServiceEnumerateDomains()
944  *
945  * Asynchronously enumerate domains available for browsing and registration.
946  *
947  * The enumeration MUST be cancelled via DNSServiceRefDeallocate() when no more domains
948  * are to be found.
949  *
950  * Note that the names returned are (like all of DNS-SD) UTF-8 strings,
951  * and are escaped using standard DNS escaping rules.
952  * (See "Notes on DNS Name Escaping" earlier in this file for more details.)
953  * A graphical browser displaying a hierarchical tree-structured view should cut
954  * the names at the bare dots to yield individual labels, then de-escape each
955  * label according to the escaping rules, and then display the resulting UTF-8 text.
956  *
957  * DNSServiceDomainEnumReply Callback Parameters:
958  *
959  * sdRef:           The DNSServiceRef initialized by DNSServiceEnumerateDomains().
960  *
961  * flags:           Possible values are:
962  *                  kDNSServiceFlagsMoreComing
963  *                  kDNSServiceFlagsAdd
964  *                  kDNSServiceFlagsDefault
965  *
966  * interfaceIndex:  Specifies the interface on which the domain exists. (The index for a given
967  *                  interface is determined via the if_nametoindex() family of calls.)
968  *
969  * errorCode:       Will be kDNSServiceErr_NoError (0) on success, otherwise indicates
970  *                  the failure that occurred (other parameters are undefined if errorCode is nonzero).
971  *
972  * replyDomain:     The name of the domain.
973  *
974  * context:         The context pointer passed to DNSServiceEnumerateDomains.
975  *
976  */
977 
978 typedef void (DNSSD_API *DNSServiceDomainEnumReply)
979 (
980     DNSServiceRef sdRef,
981     DNSServiceFlags flags,
982     uint32_t interfaceIndex,
983     DNSServiceErrorType errorCode,
984     const char                          *replyDomain,
985     void                                *context
986 );
987 
988 
989 /* DNSServiceEnumerateDomains() Parameters:
990  *
991  * sdRef:           A pointer to an uninitialized DNSServiceRef. If the call succeeds
992  *                  then it initializes the DNSServiceRef, returns kDNSServiceErr_NoError,
993  *                  and the enumeration operation will run indefinitely until the client
994  *                  terminates it by passing this DNSServiceRef to DNSServiceRefDeallocate().
995  *
996  * flags:           Possible values are:
997  *                  kDNSServiceFlagsBrowseDomains to enumerate domains recommended for browsing.
998  *                  kDNSServiceFlagsRegistrationDomains to enumerate domains recommended
999  *                  for registration.
1000  *
1001  * interfaceIndex:  If non-zero, specifies the interface on which to look for domains.
1002  *                  (the index for a given interface is determined via the if_nametoindex()
1003  *                  family of calls.) Most applications will pass 0 to enumerate domains on
1004  *                  all interfaces. See "Constants for specifying an interface index" for more details.
1005  *
1006  * callBack:        The function to be called when a domain is found or the call asynchronously
1007  *                  fails.
1008  *
1009  * context:         An application context pointer which is passed to the callback function
1010  *                  (may be NULL).
1011  *
1012  * return value:    Returns kDNSServiceErr_NoError on success (any subsequent, asynchronous
1013  *                  errors are delivered to the callback), otherwise returns an error code indicating
1014  *                  the error that occurred (the callback is not invoked and the DNSServiceRef
1015  *                  is not initialized).
1016  */
1017 
1018 DNSServiceErrorType DNSSD_API DNSServiceEnumerateDomains
1019 (
1020     DNSServiceRef                       *sdRef,
1021     DNSServiceFlags flags,
1022     uint32_t interfaceIndex,
1023     DNSServiceDomainEnumReply callBack,
1024     void                                *context  /* may be NULL */
1025 );
1026 
1027 
1028 /*********************************************************************************************
1029 *
1030 *  Service Registration
1031 *
1032 *********************************************************************************************/
1033 
1034 /* Register a service that is discovered via Browse() and Resolve() calls.
1035  *
1036  * DNSServiceRegisterReply() Callback Parameters:
1037  *
1038  * sdRef:           The DNSServiceRef initialized by DNSServiceRegister().
1039  *
1040  * flags:           When a name is successfully registered, the callback will be
1041  *                  invoked with the kDNSServiceFlagsAdd flag set. When Wide-Area
1042  *                  DNS-SD is in use, it is possible for a single service to get
1043  *                  more than one success callback (e.g. one in the "local" multicast
1044  *                  DNS domain, and another in a wide-area unicast DNS domain).
1045  *                  If a successfully-registered name later suffers a name conflict
1046  *                  or similar problem and has to be deregistered, the callback will
1047  *                  be invoked with the kDNSServiceFlagsAdd flag not set. The callback
1048  *                  is *not* invoked in the case where the caller explicitly terminates
1049  *                  the service registration by calling DNSServiceRefDeallocate(ref);
1050  *
1051  * errorCode:       Will be kDNSServiceErr_NoError on success, otherwise will
1052  *                  indicate the failure that occurred (including name conflicts,
1053  *                  if the kDNSServiceFlagsNoAutoRename flag was used when registering.)
1054  *                  Other parameters are undefined if errorCode is nonzero.
1055  *
1056  * name:            The service name registered (if the application did not specify a name in
1057  *                  DNSServiceRegister(), this indicates what name was automatically chosen).
1058  *
1059  * regtype:         The type of service registered, as it was passed to the callout.
1060  *
1061  * domain:          The domain on which the service was registered (if the application did not
1062  *                  specify a domain in DNSServiceRegister(), this indicates the default domain
1063  *                  on which the service was registered).
1064  *
1065  * context:         The context pointer that was passed to the callout.
1066  *
1067  */
1068 
1069 typedef void (DNSSD_API *DNSServiceRegisterReply)
1070 (
1071     DNSServiceRef sdRef,
1072     DNSServiceFlags flags,
1073     DNSServiceErrorType errorCode,
1074     const char                          *name,
1075     const char                          *regtype,
1076     const char                          *domain,
1077     void                                *context
1078 );
1079 
1080 
1081 /* DNSServiceRegister() Parameters:
1082  *
1083  * sdRef:           A pointer to an uninitialized DNSServiceRef. If the call succeeds
1084  *                  then it initializes the DNSServiceRef, returns kDNSServiceErr_NoError,
1085  *                  and the registration will remain active indefinitely until the client
1086  *                  terminates it by passing this DNSServiceRef to DNSServiceRefDeallocate().
1087  *
1088  * interfaceIndex:  If non-zero, specifies the interface on which to register the service
1089  *                  (the index for a given interface is determined via the if_nametoindex()
1090  *                  family of calls.) Most applications will pass 0 to register on all
1091  *                  available interfaces. See "Constants for specifying an interface index" for more details.
1092  *
1093  * flags:           Indicates the renaming behavior on name conflict (most applications
1094  *                  will pass 0). See flag definitions above for details.
1095  *
1096  * name:            If non-NULL, specifies the service name to be registered.
1097  *                  Most applications will not specify a name, in which case the computer
1098  *                  name is used (this name is communicated to the client via the callback).
1099  *                  If a name is specified, it must be 1-63 bytes of UTF-8 text.
1100  *                  If the name is longer than 63 bytes it will be automatically truncated
1101  *                  to a legal length, unless the NoAutoRename flag is set,
1102  *                  in which case kDNSServiceErr_BadParam will be returned.
1103  *
1104  * regtype:         The service type followed by the protocol, separated by a dot
1105  *                  (e.g. "_ftp._tcp"). The service type must be an underscore, followed
1106  *                  by 1-15 characters, which may be letters, digits, or hyphens.
1107  *                  The transport protocol must be "_tcp" or "_udp". New service types
1108  *                  should be registered at <http://www.dns-sd.org/ServiceTypes.html>.
1109  *
1110  *                  Additional subtypes of the primary service type (where a service
1111  *                  type has defined subtypes) follow the primary service type in a
1112  *                  comma-separated list, with no additional spaces, e.g.
1113  *                      "_primarytype._tcp,_subtype1,_subtype2,_subtype3"
1114  *                  Subtypes provide a mechanism for filtered browsing: A client browsing
1115  *                  for "_primarytype._tcp" will discover all instances of this type;
1116  *                  a client browsing for "_primarytype._tcp,_subtype2" will discover only
1117  *                  those instances that were registered with "_subtype2" in their list of
1118  *                  registered subtypes.
1119  *
1120  *                  The subtype mechanism can be illustrated with some examples using the
1121  *                  dns-sd command-line tool:
1122  *
1123  *                  % dns-sd -R Simple _test._tcp "" 1001 &
1124  *                  % dns-sd -R Better _test._tcp,HasFeatureA "" 1002 &
1125  *                  % dns-sd -R Best   _test._tcp,HasFeatureA,HasFeatureB "" 1003 &
1126  *
1127  *                  Now:
1128  *                  % dns-sd -B _test._tcp             # will find all three services
1129  *                  % dns-sd -B _test._tcp,HasFeatureA # finds "Better" and "Best"
1130  *                  % dns-sd -B _test._tcp,HasFeatureB # finds only "Best"
1131  *
1132  *                  Subtype labels may be up to 63 bytes long, and may contain any eight-
1133  *                  bit byte values, including zero bytes. However, due to the nature of
1134  *                  using a C-string-based API, conventional DNS escaping must be used for
1135  *                  dots ('.'), commas (','), backslashes ('\') and zero bytes, as shown below:
1136  *
1137  *                  % dns-sd -R Test '_test._tcp,s\.one,s\,two,s\\three,s\000four' local 123
1138  *
1139  *                  When a service is registered, all the clients browsing for the registered
1140  *                  type ("regtype") will discover it. If the discovery should be
1141  *                  restricted to a smaller set of well known peers, the service can be
1142  *                  registered with additional data (group identifier) that is known
1143  *                  only to a smaller set of peers. The group identifier should follow primary
1144  *                  service type using a colon (":") as a delimeter. If subtypes are also present,
1145  *                  it should be given before the subtype as shown below.
1146  *
1147  *                  % dns-sd -R _test1 _http._tcp:mygroup1 local 1001
1148  *                  % dns-sd -R _test2 _http._tcp:mygroup2 local 1001
1149  *                  % dns-sd -R _test3 _http._tcp:mygroup3,HasFeatureA local 1001
1150  *
1151  *                  Now:
1152  *                  % dns-sd -B _http._tcp:"mygroup1"                # will discover only test1
1153  *                  % dns-sd -B _http._tcp:"mygroup2"                # will discover only test2
1154  *                  % dns-sd -B _http._tcp:"mygroup3",HasFeatureA    # will discover only test3
1155  *
1156  *                  By specifying the group information, only the members of that group are
1157  *                  discovered.
1158  *
1159  *                  The group identifier itself is not sent in clear. Only a hash of the group
1160  *                  identifier is sent and the clients discover them anonymously. The group identifier
1161  *                  may be up to 256 bytes long and may contain any eight bit values except comma which
1162  *                  should be escaped.
1163  *
1164  * domain:          If non-NULL, specifies the domain on which to advertise the service.
1165  *                  Most applications will not specify a domain, instead automatically
1166  *                  registering in the default domain(s).
1167  *
1168  * host:            If non-NULL, specifies the SRV target host name. Most applications
1169  *                  will not specify a host, instead automatically using the machine's
1170  *                  default host name(s). Note that specifying a non-NULL host does NOT
1171  *                  create an address record for that host - the application is responsible
1172  *                  for ensuring that the appropriate address record exists, or creating it
1173  *                  via DNSServiceRegisterRecord().
1174  *
1175  * port:            The port, in network byte order, on which the service accepts connections.
1176  *                  Pass 0 for a "placeholder" service (i.e. a service that will not be discovered
1177  *                  by browsing, but will cause a name conflict if another client tries to
1178  *                  register that same name). Most clients will not use placeholder services.
1179  *
1180  * txtLen:          The length of the txtRecord, in bytes. Must be zero if the txtRecord is NULL.
1181  *
1182  * txtRecord:       The TXT record rdata. A non-NULL txtRecord MUST be a properly formatted DNS
1183  *                  TXT record, i.e. <length byte> <data> <length byte> <data> ...
1184  *                  Passing NULL for the txtRecord is allowed as a synonym for txtLen=1, txtRecord="",
1185  *                  i.e. it creates a TXT record of length one containing a single empty string.
1186  *                  RFC 1035 doesn't allow a TXT record to contain *zero* strings, so a single empty
1187  *                  string is the smallest legal DNS TXT record.
1188  *                  As with the other parameters, the DNSServiceRegister call copies the txtRecord
1189  *                  data; e.g. if you allocated the storage for the txtRecord parameter with malloc()
1190  *                  then you can safely free that memory right after the DNSServiceRegister call returns.
1191  *
1192  * callBack:        The function to be called when the registration completes or asynchronously
1193  *                  fails. The client MAY pass NULL for the callback -  The client will NOT be notified
1194  *                  of the default values picked on its behalf, and the client will NOT be notified of any
1195  *                  asynchronous errors (e.g. out of memory errors, etc.) that may prevent the registration
1196  *                  of the service. The client may NOT pass the NoAutoRename flag if the callback is NULL.
1197  *                  The client may still deregister the service at any time via DNSServiceRefDeallocate().
1198  *
1199  * context:         An application context pointer which is passed to the callback function
1200  *                  (may be NULL).
1201  *
1202  * return value:    Returns kDNSServiceErr_NoError on success (any subsequent, asynchronous
1203  *                  errors are delivered to the callback), otherwise returns an error code indicating
1204  *                  the error that occurred (the callback is never invoked and the DNSServiceRef
1205  *                  is not initialized).
1206  */
1207 
1208 DNSServiceErrorType DNSSD_API DNSServiceRegister
1209 (
1210     DNSServiceRef                       *sdRef,
1211     DNSServiceFlags flags,
1212     uint32_t interfaceIndex,
1213     const char                          *name,         /* may be NULL */
1214     const char                          *regtype,
1215     const char                          *domain,       /* may be NULL */
1216     const char                          *host,         /* may be NULL */
1217     uint16_t port,                                     /* In network byte order */
1218     uint16_t txtLen,
1219     const void                          *txtRecord,    /* may be NULL */
1220     DNSServiceRegisterReply callBack,                  /* may be NULL */
1221     void                                *context       /* may be NULL */
1222 );
1223 
1224 
1225 /* DNSServiceAddRecord()
1226  *
1227  * Add a record to a registered service. The name of the record will be the same as the
1228  * registered service's name.
1229  * The record can later be updated or deregistered by passing the RecordRef initialized
1230  * by this function to DNSServiceUpdateRecord() or DNSServiceRemoveRecord().
1231  *
1232  * Note that the DNSServiceAddRecord/UpdateRecord/RemoveRecord are *NOT* thread-safe
1233  * with respect to a single DNSServiceRef. If you plan to have multiple threads
1234  * in your program simultaneously add, update, or remove records from the same
1235  * DNSServiceRef, then it's the caller's responsibility to use a mutext lock
1236  * or take similar appropriate precautions to serialize those calls.
1237  *
1238  * Parameters;
1239  *
1240  * sdRef:           A DNSServiceRef initialized by DNSServiceRegister().
1241  *
1242  * RecordRef:       A pointer to an uninitialized DNSRecordRef. Upon succesfull completion of this
1243  *                  call, this ref may be passed to DNSServiceUpdateRecord() or DNSServiceRemoveRecord().
1244  *                  If the above DNSServiceRef is passed to DNSServiceRefDeallocate(), RecordRef is also
1245  *                  invalidated and may not be used further.
1246  *
1247  * flags:           Currently ignored, reserved for future use.
1248  *
1249  * rrtype:          The type of the record (e.g. kDNSServiceType_TXT, kDNSServiceType_SRV, etc)
1250  *
1251  * rdlen:           The length, in bytes, of the rdata.
1252  *
1253  * rdata:           The raw rdata to be contained in the added resource record.
1254  *
1255  * ttl:             The time to live of the resource record, in seconds.
1256  *                  Most clients should pass 0 to indicate that the system should
1257  *                  select a sensible default value.
1258  *
1259  * return value:    Returns kDNSServiceErr_NoError on success, otherwise returns an
1260  *                  error code indicating the error that occurred (the RecordRef is not initialized).
1261  */
1262 
1263 DNSServiceErrorType DNSSD_API DNSServiceAddRecord
1264 (
1265     DNSServiceRef sdRef,
1266     DNSRecordRef                        *RecordRef,
1267     DNSServiceFlags flags,
1268     uint16_t rrtype,
1269     uint16_t rdlen,
1270     const void                          *rdata,
1271     uint32_t ttl
1272 );
1273 
1274 
1275 /* DNSServiceUpdateRecord
1276  *
1277  * Update a registered resource record. The record must either be:
1278  *   - The primary txt record of a service registered via DNSServiceRegister()
1279  *   - A record added to a registered service via DNSServiceAddRecord()
1280  *   - An individual record registered by DNSServiceRegisterRecord()
1281  *
1282  * Parameters:
1283  *
1284  * sdRef:           A DNSServiceRef that was initialized by DNSServiceRegister()
1285  *                  or DNSServiceCreateConnection().
1286  *
1287  * RecordRef:       A DNSRecordRef initialized by DNSServiceAddRecord, or NULL to update the
1288  *                  service's primary txt record.
1289  *
1290  * flags:           Currently ignored, reserved for future use.
1291  *
1292  * rdlen:           The length, in bytes, of the new rdata.
1293  *
1294  * rdata:           The new rdata to be contained in the updated resource record.
1295  *
1296  * ttl:             The time to live of the updated resource record, in seconds.
1297  *                  Most clients should pass 0 to indicate that the system should
1298  *                  select a sensible default value.
1299  *
1300  * return value:    Returns kDNSServiceErr_NoError on success, otherwise returns an
1301  *                  error code indicating the error that occurred.
1302  */
1303 
1304 DNSServiceErrorType DNSSD_API DNSServiceUpdateRecord
1305 (
1306     DNSServiceRef sdRef,
1307     DNSRecordRef RecordRef,                            /* may be NULL */
1308     DNSServiceFlags flags,
1309     uint16_t rdlen,
1310     const void                          *rdata,
1311     uint32_t ttl
1312 );
1313 
1314 
1315 /* DNSServiceRemoveRecord
1316  *
1317  * Remove a record previously added to a service record set via DNSServiceAddRecord(), or deregister
1318  * an record registered individually via DNSServiceRegisterRecord().
1319  *
1320  * Parameters:
1321  *
1322  * sdRef:           A DNSServiceRef initialized by DNSServiceRegister() (if the
1323  *                  record being removed was registered via DNSServiceAddRecord()) or by
1324  *                  DNSServiceCreateConnection() (if the record being removed was registered via
1325  *                  DNSServiceRegisterRecord()).
1326  *
1327  * recordRef:       A DNSRecordRef initialized by a successful call to DNSServiceAddRecord()
1328  *                  or DNSServiceRegisterRecord().
1329  *
1330  * flags:           Currently ignored, reserved for future use.
1331  *
1332  * return value:    Returns kDNSServiceErr_NoError on success, otherwise returns an
1333  *                  error code indicating the error that occurred.
1334  */
1335 
1336 DNSServiceErrorType DNSSD_API DNSServiceRemoveRecord
1337 (
1338     DNSServiceRef sdRef,
1339     DNSRecordRef RecordRef,
1340     DNSServiceFlags flags
1341 );
1342 
1343 
1344 /*********************************************************************************************
1345 *
1346 *  Service Discovery
1347 *
1348 *********************************************************************************************/
1349 
1350 /* Browse for instances of a service.
1351  *
1352  * DNSServiceBrowseReply() Parameters:
1353  *
1354  * sdRef:           The DNSServiceRef initialized by DNSServiceBrowse().
1355  *
1356  * flags:           Possible values are kDNSServiceFlagsMoreComing and kDNSServiceFlagsAdd.
1357  *                  See flag definitions for details.
1358  *
1359  * interfaceIndex:  The interface on which the service is advertised. This index should
1360  *                  be passed to DNSServiceResolve() when resolving the service.
1361  *
1362  * errorCode:       Will be kDNSServiceErr_NoError (0) on success, otherwise will
1363  *                  indicate the failure that occurred. Other parameters are undefined if
1364  *                  the errorCode is nonzero.
1365  *
1366  * serviceName:     The discovered service name. This name should be displayed to the user,
1367  *                  and stored for subsequent use in the DNSServiceResolve() call.
1368  *
1369  * regtype:         The service type, which is usually (but not always) the same as was passed
1370  *                  to DNSServiceBrowse(). One case where the discovered service type may
1371  *                  not be the same as the requested service type is when using subtypes:
1372  *                  The client may want to browse for only those ftp servers that allow
1373  *                  anonymous connections. The client will pass the string "_ftp._tcp,_anon"
1374  *                  to DNSServiceBrowse(), but the type of the service that's discovered
1375  *                  is simply "_ftp._tcp". The regtype for each discovered service instance
1376  *                  should be stored along with the name, so that it can be passed to
1377  *                  DNSServiceResolve() when the service is later resolved.
1378  *
1379  * domain:          The domain of the discovered service instance. This may or may not be the
1380  *                  same as the domain that was passed to DNSServiceBrowse(). The domain for each
1381  *                  discovered service instance should be stored along with the name, so that
1382  *                  it can be passed to DNSServiceResolve() when the service is later resolved.
1383  *
1384  * context:         The context pointer that was passed to the callout.
1385  *
1386  */
1387 
1388 typedef void (DNSSD_API *DNSServiceBrowseReply)
1389 (
1390     DNSServiceRef sdRef,
1391     DNSServiceFlags flags,
1392     uint32_t interfaceIndex,
1393     DNSServiceErrorType errorCode,
1394     const char                          *serviceName,
1395     const char                          *regtype,
1396     const char                          *replyDomain,
1397     void                                *context
1398 );
1399 
1400 
1401 /* DNSServiceBrowse() Parameters:
1402  *
1403  * sdRef:           A pointer to an uninitialized DNSServiceRef. If the call succeeds
1404  *                  then it initializes the DNSServiceRef, returns kDNSServiceErr_NoError,
1405  *                  and the browse operation will run indefinitely until the client
1406  *                  terminates it by passing this DNSServiceRef to DNSServiceRefDeallocate().
1407  *
1408  * flags:           Currently ignored, reserved for future use.
1409  *
1410  * interfaceIndex:  If non-zero, specifies the interface on which to browse for services
1411  *                  (the index for a given interface is determined via the if_nametoindex()
1412  *                  family of calls.) Most applications will pass 0 to browse on all available
1413  *                  interfaces. See "Constants for specifying an interface index" for more details.
1414  *
1415  * regtype:         The service type being browsed for followed by the protocol, separated by a
1416  *                  dot (e.g. "_ftp._tcp"). The transport protocol must be "_tcp" or "_udp".
1417  *                  A client may optionally specify a single subtype to perform filtered browsing:
1418  *                  e.g. browsing for "_primarytype._tcp,_subtype" will discover only those
1419  *                  instances of "_primarytype._tcp" that were registered specifying "_subtype"
1420  *                  in their list of registered subtypes. Additionally, a group identifier may
1421  *                  also be specified before the subtype e.g., _primarytype._tcp:GroupID, which
1422  *                  will discover only the members that register the service with GroupID. See
1423  *                  DNSServiceRegister for more details.
1424  *
1425  * domain:          If non-NULL, specifies the domain on which to browse for services.
1426  *                  Most applications will not specify a domain, instead browsing on the
1427  *                  default domain(s).
1428  *
1429  * callBack:        The function to be called when an instance of the service being browsed for
1430  *                  is found, or if the call asynchronously fails.
1431  *
1432  * context:         An application context pointer which is passed to the callback function
1433  *                  (may be NULL).
1434  *
1435  * return value:    Returns kDNSServiceErr_NoError on success (any subsequent, asynchronous
1436  *                  errors are delivered to the callback), otherwise returns an error code indicating
1437  *                  the error that occurred (the callback is not invoked and the DNSServiceRef
1438  *                  is not initialized).
1439  */
1440 
1441 DNSServiceErrorType DNSSD_API DNSServiceBrowse
1442 (
1443     DNSServiceRef                       *sdRef,
1444     DNSServiceFlags flags,
1445     uint32_t interfaceIndex,
1446     const char                          *regtype,
1447     const char                          *domain,    /* may be NULL */
1448     DNSServiceBrowseReply callBack,
1449     void                                *context    /* may be NULL */
1450 );
1451 
1452 
1453 /* DNSServiceResolve()
1454  *
1455  * Resolve a service name discovered via DNSServiceBrowse() to a target host name, port number, and
1456  * txt record.
1457  *
1458  * Note: Applications should NOT use DNSServiceResolve() solely for txt record monitoring - use
1459  * DNSServiceQueryRecord() instead, as it is more efficient for this task.
1460  *
1461  * Note: When the desired results have been returned, the client MUST terminate the resolve by calling
1462  * DNSServiceRefDeallocate().
1463  *
1464  * Note: DNSServiceResolve() behaves correctly for typical services that have a single SRV record
1465  * and a single TXT record. To resolve non-standard services with multiple SRV or TXT records,
1466  * DNSServiceQueryRecord() should be used.
1467  *
1468  * DNSServiceResolveReply Callback Parameters:
1469  *
1470  * sdRef:           The DNSServiceRef initialized by DNSServiceResolve().
1471  *
1472  * flags:           Possible values: kDNSServiceFlagsMoreComing
1473  *
1474  * interfaceIndex:  The interface on which the service was resolved.
1475  *
1476  * errorCode:       Will be kDNSServiceErr_NoError (0) on success, otherwise will
1477  *                  indicate the failure that occurred. Other parameters are undefined if
1478  *                  the errorCode is nonzero.
1479  *
1480  * fullname:        The full service domain name, in the form <servicename>.<protocol>.<domain>.
1481  *                  (This name is escaped following standard DNS rules, making it suitable for
1482  *                  passing to standard system DNS APIs such as res_query(), or to the
1483  *                  special-purpose functions included in this API that take fullname parameters.
1484  *                  See "Notes on DNS Name Escaping" earlier in this file for more details.)
1485  *
1486  * hosttarget:      The target hostname of the machine providing the service. This name can
1487  *                  be passed to functions like gethostbyname() to identify the host's IP address.
1488  *
1489  * port:            The port, in network byte order, on which connections are accepted for this service.
1490  *
1491  * txtLen:          The length of the txt record, in bytes.
1492  *
1493  * txtRecord:       The service's primary txt record, in standard txt record format.
1494  *
1495  * context:         The context pointer that was passed to the callout.
1496  *
1497  * NOTE: In earlier versions of this header file, the txtRecord parameter was declared "const char *"
1498  * This is incorrect, since it contains length bytes which are values in the range 0 to 255, not -128 to +127.
1499  * Depending on your compiler settings, this change may cause signed/unsigned mismatch warnings.
1500  * These should be fixed by updating your own callback function definition to match the corrected
1501  * function signature using "const unsigned char *txtRecord". Making this change may also fix inadvertent
1502  * bugs in your callback function, where it could have incorrectly interpreted a length byte with value 250
1503  * as being -6 instead, with various bad consequences ranging from incorrect operation to software crashes.
1504  * If you need to maintain portable code that will compile cleanly with both the old and new versions of
1505  * this header file, you should update your callback function definition to use the correct unsigned value,
1506  * and then in the place where you pass your callback function to DNSServiceResolve(), use a cast to eliminate
1507  * the compiler warning, e.g.:
1508  *   DNSServiceResolve(sd, flags, index, name, regtype, domain, (DNSServiceResolveReply)MyCallback, context);
1509  * This will ensure that your code compiles cleanly without warnings (and more importantly, works correctly)
1510  * with both the old header and with the new corrected version.
1511  *
1512  */
1513 
1514 typedef void (DNSSD_API *DNSServiceResolveReply)
1515 (
1516     DNSServiceRef sdRef,
1517     DNSServiceFlags flags,
1518     uint32_t interfaceIndex,
1519     DNSServiceErrorType errorCode,
1520     const char                          *fullname,
1521     const char                          *hosttarget,
1522     uint16_t port,                                   /* In network byte order */
1523     uint16_t txtLen,
1524     const unsigned char                 *txtRecord,
1525     void                                *context
1526 );
1527 
1528 
1529 /* DNSServiceResolve() Parameters
1530  *
1531  * sdRef:           A pointer to an uninitialized DNSServiceRef. If the call succeeds
1532  *                  then it initializes the DNSServiceRef, returns kDNSServiceErr_NoError,
1533  *                  and the resolve operation will run indefinitely until the client
1534  *                  terminates it by passing this DNSServiceRef to DNSServiceRefDeallocate().
1535  *
1536  * flags:           Specifying kDNSServiceFlagsForceMulticast will cause query to be
1537  *                  performed with a link-local mDNS query, even if the name is an
1538  *                  apparently non-local name (i.e. a name not ending in ".local.")
1539  *
1540  * interfaceIndex:  The interface on which to resolve the service. If this resolve call is
1541  *                  as a result of a currently active DNSServiceBrowse() operation, then the
1542  *                  interfaceIndex should be the index reported in the DNSServiceBrowseReply
1543  *                  callback. If this resolve call is using information previously saved
1544  *                  (e.g. in a preference file) for later use, then use interfaceIndex 0, because
1545  *                  the desired service may now be reachable via a different physical interface.
1546  *                  See "Constants for specifying an interface index" for more details.
1547  *
1548  * name:            The name of the service instance to be resolved, as reported to the
1549  *                  DNSServiceBrowseReply() callback.
1550  *
1551  * regtype:         The type of the service instance to be resolved, as reported to the
1552  *                  DNSServiceBrowseReply() callback.
1553  *
1554  * domain:          The domain of the service instance to be resolved, as reported to the
1555  *                  DNSServiceBrowseReply() callback.
1556  *
1557  * callBack:        The function to be called when a result is found, or if the call
1558  *                  asynchronously fails.
1559  *
1560  * context:         An application context pointer which is passed to the callback function
1561  *                  (may be NULL).
1562  *
1563  * return value:    Returns kDNSServiceErr_NoError on success (any subsequent, asynchronous
1564  *                  errors are delivered to the callback), otherwise returns an error code indicating
1565  *                  the error that occurred (the callback is never invoked and the DNSServiceRef
1566  *                  is not initialized).
1567  */
1568 
1569 DNSServiceErrorType DNSSD_API DNSServiceResolve
1570 (
1571     DNSServiceRef                       *sdRef,
1572     DNSServiceFlags flags,
1573     uint32_t interfaceIndex,
1574     const char                          *name,
1575     const char                          *regtype,
1576     const char                          *domain,
1577     DNSServiceResolveReply callBack,
1578     void                                *context  /* may be NULL */
1579 );
1580 
1581 
1582 /*********************************************************************************************
1583 *
1584 *  Querying Individual Specific Records
1585 *
1586 *********************************************************************************************/
1587 
1588 /* DNSServiceQueryRecord
1589  *
1590  * Query for an arbitrary DNS record.
1591  *
1592  * DNSServiceQueryRecordReply() Callback Parameters:
1593  *
1594  * sdRef:           The DNSServiceRef initialized by DNSServiceQueryRecord().
1595  *
1596  * flags:           Possible values are kDNSServiceFlagsMoreComing and
1597  *                  kDNSServiceFlagsAdd. The Add flag is NOT set for PTR records
1598  *                  with a ttl of 0, i.e. "Remove" events.
1599  *
1600  * interfaceIndex:  The interface on which the query was resolved (the index for a given
1601  *                  interface is determined via the if_nametoindex() family of calls).
1602  *                  See "Constants for specifying an interface index" for more details.
1603  *
1604  * errorCode:       Will be kDNSServiceErr_NoError on success, otherwise will
1605  *                  indicate the failure that occurred. Other parameters are undefined if
1606  *                  errorCode is nonzero.
1607  *
1608  * fullname:        The resource record's full domain name.
1609  *
1610  * rrtype:          The resource record's type (e.g. kDNSServiceType_PTR, kDNSServiceType_SRV, etc)
1611  *
1612  * rrclass:         The class of the resource record (usually kDNSServiceClass_IN).
1613  *
1614  * rdlen:           The length, in bytes, of the resource record rdata.
1615  *
1616  * rdata:           The raw rdata of the resource record.
1617  *
1618  * ttl:             If the client wishes to cache the result for performance reasons,
1619  *                  the TTL indicates how long the client may legitimately hold onto
1620  *                  this result, in seconds. After the TTL expires, the client should
1621  *                  consider the result no longer valid, and if it requires this data
1622  *                  again, it should be re-fetched with a new query. Of course, this
1623  *                  only applies to clients that cancel the asynchronous operation when
1624  *                  they get a result. Clients that leave the asynchronous operation
1625  *                  running can safely assume that the data remains valid until they
1626  *                  get another callback telling them otherwise.
1627  *
1628  * context:         The context pointer that was passed to the callout.
1629  *
1630  */
1631 
1632 typedef void (DNSSD_API *DNSServiceQueryRecordReply)
1633 (
1634     DNSServiceRef sdRef,
1635     DNSServiceFlags flags,
1636     uint32_t interfaceIndex,
1637     DNSServiceErrorType errorCode,
1638     const char                          *fullname,
1639     uint16_t rrtype,
1640     uint16_t rrclass,
1641     uint16_t rdlen,
1642     const void                          *rdata,
1643     uint32_t ttl,
1644     void                                *context
1645 );
1646 
1647 
1648 /* DNSServiceQueryRecord() Parameters:
1649  *
1650  * sdRef:           A pointer to an uninitialized DNSServiceRef. If the call succeeds
1651  *                  then it initializes the DNSServiceRef, returns kDNSServiceErr_NoError,
1652  *                  and the query operation will run indefinitely until the client
1653  *                  terminates it by passing this DNSServiceRef to DNSServiceRefDeallocate().
1654  *
1655  * flags:           kDNSServiceFlagsForceMulticast or kDNSServiceFlagsLongLivedQuery.
1656  *                  Pass kDNSServiceFlagsLongLivedQuery to create a "long-lived" unicast
1657  *                  query to a unicast DNS server that implements the protocol. This flag
1658  *                  has no effect on link-local multicast queries.
1659  *
1660  * interfaceIndex:  If non-zero, specifies the interface on which to issue the query
1661  *                  (the index for a given interface is determined via the if_nametoindex()
1662  *                  family of calls.) Passing 0 causes the name to be queried for on all
1663  *                  interfaces. See "Constants for specifying an interface index" for more details.
1664  *
1665  * fullname:        The full domain name of the resource record to be queried for.
1666  *
1667  * rrtype:          The numerical type of the resource record to be queried for
1668  *                  (e.g. kDNSServiceType_PTR, kDNSServiceType_SRV, etc)
1669  *
1670  * rrclass:         The class of the resource record (usually kDNSServiceClass_IN).
1671  *
1672  * callBack:        The function to be called when a result is found, or if the call
1673  *                  asynchronously fails.
1674  *
1675  * context:         An application context pointer which is passed to the callback function
1676  *                  (may be NULL).
1677  *
1678  * return value:    Returns kDNSServiceErr_NoError on success (any subsequent, asynchronous
1679  *                  errors are delivered to the callback), otherwise returns an error code indicating
1680  *                  the error that occurred (the callback is never invoked and the DNSServiceRef
1681  *                  is not initialized).
1682  */
1683 
1684 DNSServiceErrorType DNSSD_API DNSServiceQueryRecord
1685 (
1686     DNSServiceRef                       *sdRef,
1687     DNSServiceFlags flags,
1688     uint32_t interfaceIndex,
1689     const char                          *fullname,
1690     uint16_t rrtype,
1691     uint16_t rrclass,
1692     DNSServiceQueryRecordReply callBack,
1693     void                                *context  /* may be NULL */
1694 );
1695 
1696 
1697 /*********************************************************************************************
1698 *
1699 *  Unified lookup of both IPv4 and IPv6 addresses for a fully qualified hostname
1700 *
1701 *********************************************************************************************/
1702 
1703 /* DNSServiceGetAddrInfo
1704  *
1705  * Queries for the IP address of a hostname by using either Multicast or Unicast DNS.
1706  *
1707  * DNSServiceGetAddrInfoReply() parameters:
1708  *
1709  * sdRef:           The DNSServiceRef initialized by DNSServiceGetAddrInfo().
1710  *
1711  * flags:           Possible values are kDNSServiceFlagsMoreComing and
1712  *                  kDNSServiceFlagsAdd.
1713  *
1714  * interfaceIndex:  The interface to which the answers pertain.
1715  *
1716  * errorCode:       Will be kDNSServiceErr_NoError on success, otherwise will
1717  *                  indicate the failure that occurred.  Other parameters are
1718  *                  undefined if errorCode is nonzero.
1719  *
1720  * hostname:        The fully qualified domain name of the host to be queried for.
1721  *
1722  * address:         IPv4 or IPv6 address.
1723  *
1724  * ttl:             If the client wishes to cache the result for performance reasons,
1725  *                  the TTL indicates how long the client may legitimately hold onto
1726  *                  this result, in seconds. After the TTL expires, the client should
1727  *                  consider the result no longer valid, and if it requires this data
1728  *                  again, it should be re-fetched with a new query. Of course, this
1729  *                  only applies to clients that cancel the asynchronous operation when
1730  *                  they get a result. Clients that leave the asynchronous operation
1731  *                  running can safely assume that the data remains valid until they
1732  *                  get another callback telling them otherwise.
1733  *
1734  * context:         The context pointer that was passed to the callout.
1735  *
1736  */
1737 
1738 typedef void (DNSSD_API *DNSServiceGetAddrInfoReply)
1739 (
1740     DNSServiceRef sdRef,
1741     DNSServiceFlags flags,
1742     uint32_t interfaceIndex,
1743     DNSServiceErrorType errorCode,
1744     const char                       *hostname,
1745     const struct sockaddr            *address,
1746     uint32_t ttl,
1747     void                             *context
1748 );
1749 
1750 
1751 /* DNSServiceGetAddrInfo() Parameters:
1752  *
1753  * sdRef:           A pointer to an uninitialized DNSServiceRef. If the call succeeds then it
1754  *                  initializes the DNSServiceRef, returns kDNSServiceErr_NoError, and the query
1755  *                  begins and will last indefinitely until the client terminates the query
1756  *                  by passing this DNSServiceRef to DNSServiceRefDeallocate().
1757  *
1758  * flags:           kDNSServiceFlagsForceMulticast
1759  *
1760  * interfaceIndex:  The interface on which to issue the query.  Passing 0 causes the query to be
1761  *                  sent on all active interfaces via Multicast or the primary interface via Unicast.
1762  *
1763  * protocol:        Pass in kDNSServiceProtocol_IPv4 to look up IPv4 addresses, or kDNSServiceProtocol_IPv6
1764  *                  to look up IPv6 addresses, or both to look up both kinds. If neither flag is
1765  *                  set, the system will apply an intelligent heuristic, which is (currently)
1766  *                  that it will attempt to look up both, except:
1767  *
1768  *                   * If "hostname" is a wide-area unicast DNS hostname (i.e. not a ".local." name)
1769  *                     but this host has no routable IPv6 address, then the call will not try to
1770  *                     look up IPv6 addresses for "hostname", since any addresses it found would be
1771  *                     unlikely to be of any use anyway. Similarly, if this host has no routable
1772  *                     IPv4 address, the call will not try to look up IPv4 addresses for "hostname".
1773  *
1774  * hostname:        The fully qualified domain name of the host to be queried for.
1775  *
1776  * callBack:        The function to be called when the query succeeds or fails asynchronously.
1777  *
1778  * context:         An application context pointer which is passed to the callback function
1779  *                  (may be NULL).
1780  *
1781  * return value:    Returns kDNSServiceErr_NoError on success (any subsequent, asynchronous
1782  *                  errors are delivered to the callback), otherwise returns an error code indicating
1783  *                  the error that occurred.
1784  */
1785 
1786 DNSServiceErrorType DNSSD_API DNSServiceGetAddrInfo
1787 (
1788     DNSServiceRef                    *sdRef,
1789     DNSServiceFlags flags,
1790     uint32_t interfaceIndex,
1791     DNSServiceProtocol protocol,
1792     const char                       *hostname,
1793     DNSServiceGetAddrInfoReply callBack,
1794     void                             *context          /* may be NULL */
1795 );
1796 
1797 
1798 /*********************************************************************************************
1799 *
1800 *  Special Purpose Calls:
1801 *  DNSServiceCreateConnection(), DNSServiceRegisterRecord(), DNSServiceReconfirmRecord()
1802 *  (most applications will not use these)
1803 *
1804 *********************************************************************************************/
1805 
1806 /* DNSServiceCreateConnection()
1807  *
1808  * Create a connection to the daemon allowing efficient registration of
1809  * multiple individual records.
1810  *
1811  * Parameters:
1812  *
1813  * sdRef:           A pointer to an uninitialized DNSServiceRef. Deallocating
1814  *                  the reference (via DNSServiceRefDeallocate()) severs the
1815  *                  connection and deregisters all records registered on this connection.
1816  *
1817  * return value:    Returns kDNSServiceErr_NoError on success, otherwise returns
1818  *                  an error code indicating the specific failure that occurred (in which
1819  *                  case the DNSServiceRef is not initialized).
1820  */
1821 
1822 DNSServiceErrorType DNSSD_API DNSServiceCreateConnection(DNSServiceRef *sdRef);
1823 
1824 /* DNSServiceRegisterRecord
1825  *
1826  * Register an individual resource record on a connected DNSServiceRef.
1827  *
1828  * Note that name conflicts occurring for records registered via this call must be handled
1829  * by the client in the callback.
1830  *
1831  * DNSServiceRegisterRecordReply() parameters:
1832  *
1833  * sdRef:           The connected DNSServiceRef initialized by
1834  *                  DNSServiceCreateConnection().
1835  *
1836  * RecordRef:       The DNSRecordRef initialized by DNSServiceRegisterRecord(). If the above
1837  *                  DNSServiceRef is passed to DNSServiceRefDeallocate(), this DNSRecordRef is
1838  *                  invalidated, and may not be used further.
1839  *
1840  * flags:           Currently unused, reserved for future use.
1841  *
1842  * errorCode:       Will be kDNSServiceErr_NoError on success, otherwise will
1843  *                  indicate the failure that occurred (including name conflicts.)
1844  *                  Other parameters are undefined if errorCode is nonzero.
1845  *
1846  * context:         The context pointer that was passed to the callout.
1847  *
1848  */
1849 
1850 typedef void (DNSSD_API *DNSServiceRegisterRecordReply)
1851 (
1852     DNSServiceRef sdRef,
1853     DNSRecordRef RecordRef,
1854     DNSServiceFlags flags,
1855     DNSServiceErrorType errorCode,
1856     void                                *context
1857 );
1858 
1859 
1860 /* DNSServiceRegisterRecord() Parameters:
1861  *
1862  * sdRef:           A DNSServiceRef initialized by DNSServiceCreateConnection().
1863  *
1864  * RecordRef:       A pointer to an uninitialized DNSRecordRef. Upon succesfull completion of this
1865  *                  call, this ref may be passed to DNSServiceUpdateRecord() or DNSServiceRemoveRecord().
1866  *                  (To deregister ALL records registered on a single connected DNSServiceRef
1867  *                  and deallocate each of their corresponding DNSServiceRecordRefs, call
1868  *                  DNSServiceRefDeallocate()).
1869  *
1870  * flags:           Possible values are kDNSServiceFlagsShared or kDNSServiceFlagsUnique
1871  *                  (see flag type definitions for details).
1872  *
1873  * interfaceIndex:  If non-zero, specifies the interface on which to register the record
1874  *                  (the index for a given interface is determined via the if_nametoindex()
1875  *                  family of calls.) Passing 0 causes the record to be registered on all interfaces.
1876  *                  See "Constants for specifying an interface index" for more details.
1877  *
1878  * fullname:        The full domain name of the resource record.
1879  *
1880  * rrtype:          The numerical type of the resource record (e.g. kDNSServiceType_PTR, kDNSServiceType_SRV, etc)
1881  *
1882  * rrclass:         The class of the resource record (usually kDNSServiceClass_IN)
1883  *
1884  * rdlen:           Length, in bytes, of the rdata.
1885  *
1886  * rdata:           A pointer to the raw rdata, as it is to appear in the DNS record.
1887  *
1888  * ttl:             The time to live of the resource record, in seconds.
1889  *                  Most clients should pass 0 to indicate that the system should
1890  *                  select a sensible default value.
1891  *
1892  * callBack:        The function to be called when a result is found, or if the call
1893  *                  asynchronously fails (e.g. because of a name conflict.)
1894  *
1895  * context:         An application context pointer which is passed to the callback function
1896  *                  (may be NULL).
1897  *
1898  * return value:    Returns kDNSServiceErr_NoError on success (any subsequent, asynchronous
1899  *                  errors are delivered to the callback), otherwise returns an error code indicating
1900  *                  the error that occurred (the callback is never invoked and the DNSRecordRef is
1901  *                  not initialized).
1902  */
1903 
1904 DNSServiceErrorType DNSSD_API DNSServiceRegisterRecord
1905 (
1906     DNSServiceRef sdRef,
1907     DNSRecordRef                        *RecordRef,
1908     DNSServiceFlags flags,
1909     uint32_t interfaceIndex,
1910     const char                          *fullname,
1911     uint16_t rrtype,
1912     uint16_t rrclass,
1913     uint16_t rdlen,
1914     const void                          *rdata,
1915     uint32_t ttl,
1916     DNSServiceRegisterRecordReply callBack,
1917     void                                *context    /* may be NULL */
1918 );
1919 
1920 
1921 /* DNSServiceReconfirmRecord
1922  *
1923  * Instruct the daemon to verify the validity of a resource record that appears
1924  * to be out of date (e.g. because TCP connection to a service's target failed.)
1925  * Causes the record to be flushed from the daemon's cache (as well as all other
1926  * daemons' caches on the network) if the record is determined to be invalid.
1927  * Use this routine conservatively. Reconfirming a record necessarily consumes
1928  * network bandwidth, so this should not be done indiscriminately.
1929  *
1930  * Parameters:
1931  *
1932  * flags:           Not currently used.
1933  *
1934  * interfaceIndex:  Specifies the interface of the record in question.
1935  *                  The caller must specify the interface.
1936  *                  This API (by design) causes increased network traffic, so it requires
1937  *                  the caller to be precise about which record should be reconfirmed.
1938  *                  It is not possible to pass zero for the interface index to perform
1939  *                  a "wildcard" reconfirmation, where *all* matching records are reconfirmed.
1940  *
1941  * fullname:        The resource record's full domain name.
1942  *
1943  * rrtype:          The resource record's type (e.g. kDNSServiceType_PTR, kDNSServiceType_SRV, etc)
1944  *
1945  * rrclass:         The class of the resource record (usually kDNSServiceClass_IN).
1946  *
1947  * rdlen:           The length, in bytes, of the resource record rdata.
1948  *
1949  * rdata:           The raw rdata of the resource record.
1950  *
1951  */
1952 
1953 DNSServiceErrorType DNSSD_API DNSServiceReconfirmRecord
1954 (
1955     DNSServiceFlags flags,
1956     uint32_t interfaceIndex,
1957     const char                         *fullname,
1958     uint16_t rrtype,
1959     uint16_t rrclass,
1960     uint16_t rdlen,
1961     const void                         *rdata
1962 );
1963 
1964 
1965 /*********************************************************************************************
1966 *
1967 *  NAT Port Mapping
1968 *
1969 *********************************************************************************************/
1970 
1971 /* DNSServiceNATPortMappingCreate
1972  *
1973  * Request a port mapping in the NAT gateway, which maps a port on the local machine
1974  * to an external port on the NAT. The NAT should support either PCP, NAT-PMP or the
1975  * UPnP/IGD protocol for this API to create a successful mapping. Note that this API
1976  * currently supports IPv4 addresses/mappings only. If the NAT gateway supports PCP and
1977  * returns an IPv6 address (incorrectly, since this API specifically requests IPv4
1978  * addresses), the DNSServiceNATPortMappingReply callback will be invoked with errorCode
1979  * kDNSServiceErr_NATPortMappingUnsupported.
1980  *
1981  * The port mapping will be renewed indefinitely until the client process exits, or
1982  * explicitly terminates the port mapping request by calling DNSServiceRefDeallocate().
1983  * The client callback will be invoked, informing the client of the NAT gateway's
1984  * external IP address and the external port that has been allocated for this client.
1985  * The client should then record this external IP address and port using whatever
1986  * directory service mechanism it is using to enable peers to connect to it.
1987  * (Clients advertising services using Wide-Area DNS-SD DO NOT need to use this API
1988  * -- when a client calls DNSServiceRegister() NAT mappings are automatically created
1989  * and the external IP address and port for the service are recorded in the global DNS.
1990  * Only clients using some directory mechanism other than Wide-Area DNS-SD need to use
1991  * this API to explicitly map their own ports.)
1992  *
1993  * It's possible that the client callback could be called multiple times, for example
1994  * if the NAT gateway's IP address changes, or if a configuration change results in a
1995  * different external port being mapped for this client. Over the lifetime of any long-lived
1996  * port mapping, the client should be prepared to handle these notifications of changes
1997  * in the environment, and should update its recorded address and/or port as appropriate.
1998  *
1999  * NOTE: There are two unusual aspects of how the DNSServiceNATPortMappingCreate API works,
2000  * which were intentionally designed to help simplify client code:
2001  *
2002  *  1. It's not an error to request a NAT mapping when the machine is not behind a NAT gateway.
2003  *     In other NAT mapping APIs, if you request a NAT mapping and the machine is not behind a NAT
2004  *     gateway, then the API returns an error code -- it can't get you a NAT mapping if there's no
2005  *     NAT gateway. The DNSServiceNATPortMappingCreate API takes a different view. Working out
2006  *     whether or not you need a NAT mapping can be tricky and non-obvious, particularly on
2007  *     a machine with multiple active network interfaces. Rather than make every client recreate
2008  *     this logic for deciding whether a NAT mapping is required, the PortMapping API does that
2009  *     work for you. If the client calls the PortMapping API when the machine already has a
2010  *     routable public IP address, then instead of complaining about it and giving an error,
2011  *     the PortMapping API just invokes your callback, giving the machine's public address
2012  *     and your own port number. This means you don't need to write code to work out whether
2013  *     your client needs to call the PortMapping API -- just call it anyway, and if it wasn't
2014  *     necessary, no harm is done:
2015  *
2016  *     - If the machine already has a routable public IP address, then your callback
2017  *       will just be invoked giving your own address and port.
2018  *     - If a NAT mapping is required and obtained, then your callback will be invoked
2019  *       giving you the external address and port.
2020  *     - If a NAT mapping is required but not obtained from the local NAT gateway,
2021  *       or the machine has no network connectivity, then your callback will be
2022  *       invoked giving zero address and port.
2023  *
2024  *  2. In other NAT mapping APIs, if a laptop computer is put to sleep and woken up on a new
2025  *     network, it's the client's job to notice this, and work out whether a NAT mapping
2026  *     is required on the new network, and make a new NAT mapping request if necessary.
2027  *     The DNSServiceNATPortMappingCreate API does this for you, automatically.
2028  *     The client just needs to make one call to the PortMapping API, and its callback will
2029  *     be invoked any time the mapping state changes. This property complements point (1) above.
2030  *     If the client didn't make a NAT mapping request just because it determined that one was
2031  *     not required at that particular moment in time, the client would then have to monitor
2032  *     for network state changes to determine if a NAT port mapping later became necessary.
2033  *     By unconditionally making a NAT mapping request, even when a NAT mapping not to be
2034  *     necessary, the PortMapping API will then begin monitoring network state changes on behalf of
2035  *     the client, and if a NAT mapping later becomes necessary, it will automatically create a NAT
2036  *     mapping and inform the client with a new callback giving the new address and port information.
2037  *
2038  * DNSServiceNATPortMappingReply() parameters:
2039  *
2040  * sdRef:           The DNSServiceRef initialized by DNSServiceNATPortMappingCreate().
2041  *
2042  * flags:           Currently unused, reserved for future use.
2043  *
2044  * interfaceIndex:  The interface through which the NAT gateway is reached.
2045  *
2046  * errorCode:       Will be kDNSServiceErr_NoError on success.
2047  *                  Will be kDNSServiceErr_DoubleNAT when the NAT gateway is itself behind one or
2048  *                  more layers of NAT, in which case the other parameters have the defined values.
2049  *                  For other failures, will indicate the failure that occurred, and the other
2050  *                  parameters are undefined.
2051  *
2052  * externalAddress: Four byte IPv4 address in network byte order.
2053  *
2054  * protocol:        Will be kDNSServiceProtocol_UDP or kDNSServiceProtocol_TCP or both.
2055  *
2056  * internalPort:    The port on the local machine that was mapped.
2057  *
2058  * externalPort:    The actual external port in the NAT gateway that was mapped.
2059  *                  This is likely to be different than the requested external port.
2060  *
2061  * ttl:             The lifetime of the NAT port mapping created on the gateway.
2062  *                  This controls how quickly stale mappings will be garbage-collected
2063  *                  if the client machine crashes, suffers a power failure, is disconnected
2064  *                  from the network, or suffers some other unfortunate demise which
2065  *                  causes it to vanish without explicitly removing its NAT port mapping.
2066  *                  It's possible that the ttl value will differ from the requested ttl value.
2067  *
2068  * context:         The context pointer that was passed to the callout.
2069  *
2070  */
2071 
2072 typedef void (DNSSD_API *DNSServiceNATPortMappingReply)
2073 (
2074     DNSServiceRef sdRef,
2075     DNSServiceFlags flags,
2076     uint32_t interfaceIndex,
2077     DNSServiceErrorType errorCode,
2078     uint32_t externalAddress,                           /* four byte IPv4 address in network byte order */
2079     DNSServiceProtocol protocol,
2080     uint16_t internalPort,                              /* In network byte order */
2081     uint16_t externalPort,                              /* In network byte order and may be different than the requested port */
2082     uint32_t ttl,                                       /* may be different than the requested ttl */
2083     void                             *context
2084 );
2085 
2086 
2087 /* DNSServiceNATPortMappingCreate() Parameters:
2088  *
2089  * sdRef:           A pointer to an uninitialized DNSServiceRef. If the call succeeds then it
2090  *                  initializes the DNSServiceRef, returns kDNSServiceErr_NoError, and the nat
2091  *                  port mapping will last indefinitely until the client terminates the port
2092  *                  mapping request by passing this DNSServiceRef to DNSServiceRefDeallocate().
2093  *
2094  * flags:           Currently ignored, reserved for future use.
2095  *
2096  * interfaceIndex:  The interface on which to create port mappings in a NAT gateway. Passing 0 causes
2097  *                  the port mapping request to be sent on the primary interface.
2098  *
2099  * protocol:        To request a port mapping, pass in kDNSServiceProtocol_UDP, or kDNSServiceProtocol_TCP,
2100  *                  or (kDNSServiceProtocol_UDP | kDNSServiceProtocol_TCP) to map both.
2101  *                  The local listening port number must also be specified in the internalPort parameter.
2102  *                  To just discover the NAT gateway's external IP address, pass zero for protocol,
2103  *                  internalPort, externalPort and ttl.
2104  *
2105  * internalPort:    The port number in network byte order on the local machine which is listening for packets.
2106  *
2107  * externalPort:    The requested external port in network byte order in the NAT gateway that you would
2108  *                  like to map to the internal port. Pass 0 if you don't care which external port is chosen for you.
2109  *
2110  * ttl:             The requested renewal period of the NAT port mapping, in seconds.
2111  *                  If the client machine crashes, suffers a power failure, is disconnected from
2112  *                  the network, or suffers some other unfortunate demise which causes it to vanish
2113  *                  unexpectedly without explicitly removing its NAT port mappings, then the NAT gateway
2114  *                  will garbage-collect old stale NAT port mappings when their lifetime expires.
2115  *                  Requesting a short TTL causes such orphaned mappings to be garbage-collected
2116  *                  more promptly, but consumes system resources and network bandwidth with
2117  *                  frequent renewal packets to keep the mapping from expiring.
2118  *                  Requesting a long TTL is more efficient on the network, but in the event of the
2119  *                  client vanishing, stale NAT port mappings will not be garbage-collected as quickly.
2120  *                  Most clients should pass 0 to use a system-wide default value.
2121  *
2122  * callBack:        The function to be called when the port mapping request succeeds or fails asynchronously.
2123  *
2124  * context:         An application context pointer which is passed to the callback function
2125  *                  (may be NULL).
2126  *
2127  * return value:    Returns kDNSServiceErr_NoError on success (any subsequent, asynchronous
2128  *                  errors are delivered to the callback), otherwise returns an error code indicating
2129  *                  the error that occurred.
2130  *
2131  *                  If you don't actually want a port mapped, and are just calling the API
2132  *                  because you want to find out the NAT's external IP address (e.g. for UI
2133  *                  display) then pass zero for protocol, internalPort, externalPort and ttl.
2134  */
2135 
2136 DNSServiceErrorType DNSSD_API DNSServiceNATPortMappingCreate
2137 (
2138     DNSServiceRef                    *sdRef,
2139     DNSServiceFlags flags,
2140     uint32_t interfaceIndex,
2141     DNSServiceProtocol protocol,                        /* TCP and/or UDP          */
2142     uint16_t internalPort,                              /* network byte order      */
2143     uint16_t externalPort,                              /* network byte order      */
2144     uint32_t ttl,                                       /* time to live in seconds */
2145     DNSServiceNATPortMappingReply callBack,
2146     void                             *context           /* may be NULL             */
2147 );
2148 
2149 
2150 /*********************************************************************************************
2151 *
2152 *  General Utility Functions
2153 *
2154 *********************************************************************************************/
2155 
2156 /* DNSServiceConstructFullName()
2157  *
2158  * Concatenate a three-part domain name (as returned by the above callbacks) into a
2159  * properly-escaped full domain name. Note that callbacks in the above functions ALREADY ESCAPE
2160  * strings where necessary.
2161  *
2162  * Parameters:
2163  *
2164  * fullName:        A pointer to a buffer that where the resulting full domain name is to be written.
2165  *                  The buffer must be kDNSServiceMaxDomainName (1009) bytes in length to
2166  *                  accommodate the longest legal domain name without buffer overrun.
2167  *
2168  * service:         The service name - any dots or backslashes must NOT be escaped.
2169  *                  May be NULL (to construct a PTR record name, e.g.
2170  *                  "_ftp._tcp.apple.com.").
2171  *
2172  * regtype:         The service type followed by the protocol, separated by a dot
2173  *                  (e.g. "_ftp._tcp").
2174  *
2175  * domain:          The domain name, e.g. "apple.com.". Literal dots or backslashes,
2176  *                  if any, must be escaped, e.g. "1st\. Floor.apple.com."
2177  *
2178  * return value:    Returns kDNSServiceErr_NoError (0) on success, kDNSServiceErr_BadParam on error.
2179  *
2180  */
2181 
2182 DNSServiceErrorType DNSSD_API DNSServiceConstructFullName
2183 (
2184     char                            * const fullName,
2185     const char                      * const service,      /* may be NULL */
2186     const char                      * const regtype,
2187     const char                      * const domain
2188 );
2189 
2190 
2191 /*********************************************************************************************
2192 *
2193 *   TXT Record Construction Functions
2194 *
2195 *********************************************************************************************/
2196 
2197 /*
2198  * A typical calling sequence for TXT record construction is something like:
2199  *
2200  * Client allocates storage for TXTRecord data (e.g. declare buffer on the stack)
2201  * TXTRecordCreate();
2202  * TXTRecordSetValue();
2203  * TXTRecordSetValue();
2204  * TXTRecordSetValue();
2205  * ...
2206  * DNSServiceRegister( ... TXTRecordGetLength(), TXTRecordGetBytesPtr() ... );
2207  * TXTRecordDeallocate();
2208  * Explicitly deallocate storage for TXTRecord data (if not allocated on the stack)
2209  */
2210 
2211 
2212 /* TXTRecordRef
2213  *
2214  * Opaque internal data type.
2215  * Note: Represents a DNS-SD TXT record.
2216  */
2217 
2218 typedef union _TXTRecordRef_t { char PrivateData[16]; char *ForceNaturalAlignment; } TXTRecordRef;
2219 
2220 
2221 /* TXTRecordCreate()
2222  *
2223  * Creates a new empty TXTRecordRef referencing the specified storage.
2224  *
2225  * If the buffer parameter is NULL, or the specified storage size is not
2226  * large enough to hold a key subsequently added using TXTRecordSetValue(),
2227  * then additional memory will be added as needed using malloc().
2228  *
2229  * On some platforms, when memory is low, malloc() may fail. In this
2230  * case, TXTRecordSetValue() will return kDNSServiceErr_NoMemory, and this
2231  * error condition will need to be handled as appropriate by the caller.
2232  *
2233  * You can avoid the need to handle this error condition if you ensure
2234  * that the storage you initially provide is large enough to hold all
2235  * the key/value pairs that are to be added to the record.
2236  * The caller can precompute the exact length required for all of the
2237  * key/value pairs to be added, or simply provide a fixed-sized buffer
2238  * known in advance to be large enough.
2239  * A no-value (key-only) key requires  (1 + key length) bytes.
2240  * A key with empty value requires     (1 + key length + 1) bytes.
2241  * A key with non-empty value requires (1 + key length + 1 + value length).
2242  * For most applications, DNS-SD TXT records are generally
2243  * less than 100 bytes, so in most cases a simple fixed-sized
2244  * 256-byte buffer will be more than sufficient.
2245  * Recommended size limits for DNS-SD TXT Records are discussed in
2246  * <http://files.dns-sd.org/draft-cheshire-dnsext-dns-sd.txt>
2247  *
2248  * Note: When passing parameters to and from these TXT record APIs,
2249  * the key name does not include the '=' character. The '=' character
2250  * is the separator between the key and value in the on-the-wire
2251  * packet format; it is not part of either the key or the value.
2252  *
2253  * txtRecord:       A pointer to an uninitialized TXTRecordRef.
2254  *
2255  * bufferLen:       The size of the storage provided in the "buffer" parameter.
2256  *
2257  * buffer:          Optional caller-supplied storage used to hold the TXTRecord data.
2258  *                  This storage must remain valid for as long as
2259  *                  the TXTRecordRef.
2260  */
2261 
2262 void DNSSD_API TXTRecordCreate
2263 (
2264     TXTRecordRef     *txtRecord,
2265     uint16_t bufferLen,
2266     void             *buffer
2267 );
2268 
2269 
2270 /* TXTRecordDeallocate()
2271  *
2272  * Releases any resources allocated in the course of preparing a TXT Record
2273  * using TXTRecordCreate()/TXTRecordSetValue()/TXTRecordRemoveValue().
2274  * Ownership of the buffer provided in TXTRecordCreate() returns to the client.
2275  *
2276  * txtRecord:           A TXTRecordRef initialized by calling TXTRecordCreate().
2277  *
2278  */
2279 
2280 void DNSSD_API TXTRecordDeallocate
2281 (
2282     TXTRecordRef     *txtRecord
2283 );
2284 
2285 
2286 /* TXTRecordSetValue()
2287  *
2288  * Adds a key (optionally with value) to a TXTRecordRef. If the "key" already
2289  * exists in the TXTRecordRef, then the current value will be replaced with
2290  * the new value.
2291  * Keys may exist in four states with respect to a given TXT record:
2292  *  - Absent (key does not appear at all)
2293  *  - Present with no value ("key" appears alone)
2294  *  - Present with empty value ("key=" appears in TXT record)
2295  *  - Present with non-empty value ("key=value" appears in TXT record)
2296  * For more details refer to "Data Syntax for DNS-SD TXT Records" in
2297  * <http://files.dns-sd.org/draft-cheshire-dnsext-dns-sd.txt>
2298  *
2299  * txtRecord:       A TXTRecordRef initialized by calling TXTRecordCreate().
2300  *
2301  * key:             A null-terminated string which only contains printable ASCII
2302  *                  values (0x20-0x7E), excluding '=' (0x3D). Keys should be
2303  *                  9 characters or fewer (not counting the terminating null).
2304  *
2305  * valueSize:       The size of the value.
2306  *
2307  * value:           Any binary value. For values that represent
2308  *                  textual data, UTF-8 is STRONGLY recommended.
2309  *                  For values that represent textual data, valueSize
2310  *                  should NOT include the terminating null (if any)
2311  *                  at the end of the string.
2312  *                  If NULL, then "key" will be added with no value.
2313  *                  If non-NULL but valueSize is zero, then "key=" will be
2314  *                  added with empty value.
2315  *
2316  * return value:    Returns kDNSServiceErr_NoError on success.
2317  *                  Returns kDNSServiceErr_Invalid if the "key" string contains
2318  *                  illegal characters.
2319  *                  Returns kDNSServiceErr_NoMemory if adding this key would
2320  *                  exceed the available storage.
2321  */
2322 
2323 DNSServiceErrorType DNSSD_API TXTRecordSetValue
2324 (
2325     TXTRecordRef     *txtRecord,
2326     const char       *key,
2327     uint8_t valueSize,                 /* may be zero */
2328     const void       *value            /* may be NULL */
2329 );
2330 
2331 
2332 /* TXTRecordRemoveValue()
2333  *
2334  * Removes a key from a TXTRecordRef. The "key" must be an
2335  * ASCII string which exists in the TXTRecordRef.
2336  *
2337  * txtRecord:       A TXTRecordRef initialized by calling TXTRecordCreate().
2338  *
2339  * key:             A key name which exists in the TXTRecordRef.
2340  *
2341  * return value:    Returns kDNSServiceErr_NoError on success.
2342  *                  Returns kDNSServiceErr_NoSuchKey if the "key" does not
2343  *                  exist in the TXTRecordRef.
2344  */
2345 
2346 DNSServiceErrorType DNSSD_API TXTRecordRemoveValue
2347 (
2348     TXTRecordRef     *txtRecord,
2349     const char       *key
2350 );
2351 
2352 
2353 /* TXTRecordGetLength()
2354  *
2355  * Allows you to determine the length of the raw bytes within a TXTRecordRef.
2356  *
2357  * txtRecord:       A TXTRecordRef initialized by calling TXTRecordCreate().
2358  *
2359  * return value:    Returns the size of the raw bytes inside a TXTRecordRef
2360  *                  which you can pass directly to DNSServiceRegister() or
2361  *                  to DNSServiceUpdateRecord().
2362  *                  Returns 0 if the TXTRecordRef is empty.
2363  */
2364 
2365 uint16_t DNSSD_API TXTRecordGetLength
2366 (
2367     const TXTRecordRef *txtRecord
2368 );
2369 
2370 
2371 /* TXTRecordGetBytesPtr()
2372  *
2373  * Allows you to retrieve a pointer to the raw bytes within a TXTRecordRef.
2374  *
2375  * txtRecord:       A TXTRecordRef initialized by calling TXTRecordCreate().
2376  *
2377  * return value:    Returns a pointer to the raw bytes inside the TXTRecordRef
2378  *                  which you can pass directly to DNSServiceRegister() or
2379  *                  to DNSServiceUpdateRecord().
2380  */
2381 
2382 const void * DNSSD_API TXTRecordGetBytesPtr
2383 (
2384     const TXTRecordRef *txtRecord
2385 );
2386 
2387 
2388 /*********************************************************************************************
2389 *
2390 *   TXT Record Parsing Functions
2391 *
2392 *********************************************************************************************/
2393 
2394 /*
2395  * A typical calling sequence for TXT record parsing is something like:
2396  *
2397  * Receive TXT record data in DNSServiceResolve() callback
2398  * if (TXTRecordContainsKey(txtLen, txtRecord, "key")) then do something
2399  * val1ptr = TXTRecordGetValuePtr(txtLen, txtRecord, "key1", &len1);
2400  * val2ptr = TXTRecordGetValuePtr(txtLen, txtRecord, "key2", &len2);
2401  * ...
2402  * memcpy(myval1, val1ptr, len1);
2403  * memcpy(myval2, val2ptr, len2);
2404  * ...
2405  * return;
2406  *
2407  * If you wish to retain the values after return from the DNSServiceResolve()
2408  * callback, then you need to copy the data to your own storage using memcpy()
2409  * or similar, as shown in the example above.
2410  *
2411  * If for some reason you need to parse a TXT record you built yourself
2412  * using the TXT record construction functions above, then you can do
2413  * that using TXTRecordGetLength and TXTRecordGetBytesPtr calls:
2414  * TXTRecordGetValue(TXTRecordGetLength(x), TXTRecordGetBytesPtr(x), key, &len);
2415  *
2416  * Most applications only fetch keys they know about from a TXT record and
2417  * ignore the rest.
2418  * However, some debugging tools wish to fetch and display all keys.
2419  * To do that, use the TXTRecordGetCount() and TXTRecordGetItemAtIndex() calls.
2420  */
2421 
2422 /* TXTRecordContainsKey()
2423  *
2424  * Allows you to determine if a given TXT Record contains a specified key.
2425  *
2426  * txtLen:          The size of the received TXT Record.
2427  *
2428  * txtRecord:       Pointer to the received TXT Record bytes.
2429  *
2430  * key:             A null-terminated ASCII string containing the key name.
2431  *
2432  * return value:    Returns 1 if the TXT Record contains the specified key.
2433  *                  Otherwise, it returns 0.
2434  */
2435 
2436 int DNSSD_API TXTRecordContainsKey
2437 (
2438     uint16_t txtLen,
2439     const void       *txtRecord,
2440     const char       *key
2441 );
2442 
2443 
2444 /* TXTRecordGetValuePtr()
2445  *
2446  * Allows you to retrieve the value for a given key from a TXT Record.
2447  *
2448  * txtLen:          The size of the received TXT Record
2449  *
2450  * txtRecord:       Pointer to the received TXT Record bytes.
2451  *
2452  * key:             A null-terminated ASCII string containing the key name.
2453  *
2454  * valueLen:        On output, will be set to the size of the "value" data.
2455  *
2456  * return value:    Returns NULL if the key does not exist in this TXT record,
2457  *                  or exists with no value (to differentiate between
2458  *                  these two cases use TXTRecordContainsKey()).
2459  *                  Returns pointer to location within TXT Record bytes
2460  *                  if the key exists with empty or non-empty value.
2461  *                  For empty value, valueLen will be zero.
2462  *                  For non-empty value, valueLen will be length of value data.
2463  */
2464 
2465 const void * DNSSD_API TXTRecordGetValuePtr
2466 (
2467     uint16_t txtLen,
2468     const void       *txtRecord,
2469     const char       *key,
2470     uint8_t          *valueLen
2471 );
2472 
2473 
2474 /* TXTRecordGetCount()
2475  *
2476  * Returns the number of keys stored in the TXT Record. The count
2477  * can be used with TXTRecordGetItemAtIndex() to iterate through the keys.
2478  *
2479  * txtLen:          The size of the received TXT Record.
2480  *
2481  * txtRecord:       Pointer to the received TXT Record bytes.
2482  *
2483  * return value:    Returns the total number of keys in the TXT Record.
2484  *
2485  */
2486 
2487 uint16_t DNSSD_API TXTRecordGetCount
2488 (
2489     uint16_t txtLen,
2490     const void       *txtRecord
2491 );
2492 
2493 
2494 /* TXTRecordGetItemAtIndex()
2495  *
2496  * Allows you to retrieve a key name and value pointer, given an index into
2497  * a TXT Record. Legal index values range from zero to TXTRecordGetCount()-1.
2498  * It's also possible to iterate through keys in a TXT record by simply
2499  * calling TXTRecordGetItemAtIndex() repeatedly, beginning with index zero
2500  * and increasing until TXTRecordGetItemAtIndex() returns kDNSServiceErr_Invalid.
2501  *
2502  * On return:
2503  * For keys with no value, *value is set to NULL and *valueLen is zero.
2504  * For keys with empty value, *value is non-NULL and *valueLen is zero.
2505  * For keys with non-empty value, *value is non-NULL and *valueLen is non-zero.
2506  *
2507  * txtLen:          The size of the received TXT Record.
2508  *
2509  * txtRecord:       Pointer to the received TXT Record bytes.
2510  *
2511  * itemIndex:       An index into the TXT Record.
2512  *
2513  * keyBufLen:       The size of the string buffer being supplied.
2514  *
2515  * key:             A string buffer used to store the key name.
2516  *                  On return, the buffer contains a null-terminated C string
2517  *                  giving the key name. DNS-SD TXT keys are usually
2518  *                  9 characters or fewer. To hold the maximum possible
2519  *                  key name, the buffer should be 256 bytes long.
2520  *
2521  * valueLen:        On output, will be set to the size of the "value" data.
2522  *
2523  * value:           On output, *value is set to point to location within TXT
2524  *                  Record bytes that holds the value data.
2525  *
2526  * return value:    Returns kDNSServiceErr_NoError on success.
2527  *                  Returns kDNSServiceErr_NoMemory if keyBufLen is too short.
2528  *                  Returns kDNSServiceErr_Invalid if index is greater than
2529  *                  TXTRecordGetCount()-1.
2530  */
2531 
2532 DNSServiceErrorType DNSSD_API TXTRecordGetItemAtIndex
2533 (
2534     uint16_t txtLen,
2535     const void       *txtRecord,
2536     uint16_t itemIndex,
2537     uint16_t keyBufLen,
2538     char             *key,
2539     uint8_t          *valueLen,
2540     const void       **value
2541 );
2542 
2543 #if _DNS_SD_LIBDISPATCH
2544 /*
2545  * DNSServiceSetDispatchQueue
2546  *
2547  * Allows you to schedule a DNSServiceRef on a serial dispatch queue for receiving asynchronous
2548  * callbacks.  It's the clients responsibility to ensure that the provided dispatch queue is running.
2549  *
2550  * A typical application that uses CFRunLoopRun or dispatch_main on its main thread will
2551  * usually schedule DNSServiceRefs on its main queue (which is always a serial queue)
2552  * using "DNSServiceSetDispatchQueue(sdref, dispatch_get_main_queue());"
2553  *
2554  * If there is any error during the processing of events, the application callback will
2555  * be called with an error code. For shared connections, each subordinate DNSServiceRef
2556  * will get its own error callback. Currently these error callbacks only happen
2557  * if the daemon is manually terminated or crashes, and the error
2558  * code in this case is kDNSServiceErr_ServiceNotRunning. The application must call
2559  * DNSServiceRefDeallocate to free the DNSServiceRef when it gets such an error code.
2560  * These error callbacks are rare and should not normally happen on customer machines,
2561  * but application code should be written defensively to handle such error callbacks
2562  * gracefully if they occur.
2563  *
2564  * After using DNSServiceSetDispatchQueue on a DNSServiceRef, calling DNSServiceProcessResult
2565  * on the same DNSServiceRef will result in undefined behavior and should be avoided.
2566  *
2567  * Once the application successfully schedules a DNSServiceRef on a serial dispatch queue using
2568  * DNSServiceSetDispatchQueue, it cannot remove the DNSServiceRef from the dispatch queue, or use
2569  * DNSServiceSetDispatchQueue a second time to schedule the DNSServiceRef onto a different serial dispatch
2570  * queue. Once scheduled onto a dispatch queue a DNSServiceRef will deliver events to that queue until
2571  * the application no longer requires that operation and terminates it using DNSServiceRefDeallocate.
2572  *
2573  * service:         DNSServiceRef that was allocated and returned to the application, when the
2574  *                  application calls one of the DNSService API.
2575  *
2576  * queue:           dispatch queue where the application callback will be scheduled
2577  *
2578  * return value:    Returns kDNSServiceErr_NoError on success.
2579  *                  Returns kDNSServiceErr_NoMemory if it cannot create a dispatch source
2580  *                  Returns kDNSServiceErr_BadParam if the service param is invalid or the
2581  *                  queue param is invalid
2582  */
2583 
2584 DNSServiceErrorType DNSSD_API DNSServiceSetDispatchQueue
2585 (
2586     DNSServiceRef service,
2587     dispatch_queue_t queue
2588 );
2589 #endif //_DNS_SD_LIBDISPATCH
2590 
2591 #if !defined(_WIN32)
2592 typedef void (DNSSD_API *DNSServiceSleepKeepaliveReply)
2593 (
2594     DNSServiceRef sdRef,
2595     DNSServiceErrorType errorCode,
2596     void                                *context
2597 );
2598 DNSServiceErrorType DNSSD_API DNSServiceSleepKeepalive
2599 (
2600     DNSServiceRef                       *sdRef,
2601     DNSServiceFlags flags,
2602     int fd,
2603     unsigned int timeout,
2604     DNSServiceSleepKeepaliveReply callBack,
2605     void                                *context
2606 );
2607 #endif
2608 
2609 #ifdef APPLE_OSX_mDNSResponder
2610 /* DNSServiceCreateDelegateConnection()
2611  *
2612  * Create a delegate connection to the daemon allowing efficient registration of
2613  * multiple individual records.
2614  *
2615  * Parameters:
2616  *
2617  * sdRef:           A pointer to an uninitialized DNSServiceRef. Deallocating
2618  *                  the reference (via DNSServiceRefDeallocate()) severs the
2619  *                  connection and deregisters all records registered on this connection.
2620  *
2621  * pid :            Process ID of the delegate
2622  *
2623  * uuid:            UUID of the delegate
2624  *
2625  *                  Note that only one of the two arguments (pid or uuid) can be specified. If pid
2626  *                  is zero, uuid will be assumed to be a valid value; otherwise pid will be used.
2627  *
2628  * return value:    Returns kDNSServiceErr_NoError on success, otherwise returns
2629  *                  an error code indicating the specific failure that occurred (in which
2630  *                  case the DNSServiceRef is not initialized). kDNSServiceErr_NotAuth is
2631  *                  returned to indicate that the calling process does not have entitlements
2632  *                  to use this API.
2633  */
2634 DNSServiceErrorType DNSSD_API DNSServiceCreateDelegateConnection(DNSServiceRef *sdRef, int32_t pid, uuid_t uuid);
2635 #endif
2636 
2637 #ifdef __APPLE_API_PRIVATE
2638 
2639 #define kDNSServiceCompPrivateDNS   "PrivateDNS"
2640 #define kDNSServiceCompMulticastDNS "MulticastDNS"
2641 
2642 #endif //__APPLE_API_PRIVATE
2643 
2644 /* Some C compiler cleverness. We can make the compiler check certain things for us,
2645  * and report errors at compile-time if anything is wrong. The usual way to do this would
2646  * be to use a run-time "if" statement or the conventional run-time "assert" mechanism, but
2647  * then you don't find out what's wrong until you run the software. This way, if the assertion
2648  * condition is false, the array size is negative, and the complier complains immediately.
2649  */
2650 
2651 struct CompileTimeAssertionChecks_DNS_SD
2652 {
2653     char assert0[(sizeof(union _TXTRecordRef_t) == 16) ? 1 : -1];
2654 };
2655 
2656 #ifdef  __cplusplus
2657 }
2658 #endif
2659 
2660 #endif  /* _DNS_SD_H */
2661