/* -*- Mode: C; tab-width: 4 -*-
 *
 * Copyright (c) 2003-2004, Apple Computer, Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1.  Redistributions of source code must retain the above copyright notice,
 *     this list of conditions and the following disclaimer.
 * 2.  Redistributions in binary form must reproduce the above copyright notice,
 *     this list of conditions and the following disclaimer in the documentation
 *     and/or other materials provided with the distribution.
 * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of its
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 *     software without specific prior written permission.
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/*! @header     DNS Service Discovery
 *
 * @discussion  This section describes the functions, callbacks, and data
 * structures that make up the DNS Service Discovery API.
 *
 *              The DNS Service Discovery API is part of Bonjour, Apple's
 * implementation of zero-configuration networking (ZEROCONF).
 *
 *              Bonjour allows you to register a network service, such as a
 *              printer or file server, so that it can be found by name or
 * browsed for by service type and domain. Using Bonjour, applications can
 *              discover what services are available on the network, along with
 *              all the information -- such as name, IP address, and port --
 *              necessary to access a particular service.
 *
 *              In effect, Bonjour combines the functions of a local DNS server
 * and AppleTalk. Bonjour allows applications to provide user-friendly printer
 *              and server browsing, among other things, over standard IP
 * networks. This behavior is a result of combining protocols such as multicast
 * and DNS to add new functionality to the network (such as multicast DNS).
 *
 *              Bonjour gives applications easy access to services over local IP
 *              networks without requiring the service or the application to
 * support an AppleTalk or a Netbeui stack, and without requiring a DNS server
 *              for the local network.
 */

/* _DNS_SD_H contains the mDNSResponder version number for this header file,
 * formatted as follows: Major part of the build number * 10000 + minor part of
 * the build number *   100 For example, Mac OS X 10.4.9 has
 * mDNSResponder-108.4, which would be represented as version 1080400. This
 * allows C code to do simple greater-than and less-than comparisons: e.g. an
 * application that requires the DNSServiceGetProperty() call (new in
 * mDNSResponder-126) can check:
 *
 *   #if _DNS_SD_H+0 >= 1260000
 *   ... some C code that calls DNSServiceGetProperty() ...
 *   #endif
 *
 * The version defined in this header file symbol allows for compile-time
 * checking, so that C code building with earlier versions of the header file
 * can avoid compile errors trying to use functions that aren't even defined
 * in those earlier versions. Similar checks may also be performed at run-time:
 *  => weak linking -- to avoid link failures if run with an earlier
 *     version of the library that's missing some desired symbol, or
 *  => DNSServiceGetProperty(DaemonVersion) -- to verify whether the running
 * daemon
 *     ("system service" on Windows) meets some required minimum functionality
 * level.
 */

#ifndef _DNS_SD_H
#define _DNS_SD_H 3331000

#ifdef __cplusplus
extern "C" {
#endif

/* Set to 1 if libdispatch is supported
 * Note: May also be set by project and/or Makefile
 */
#ifndef _DNS_SD_LIBDISPATCH
#define _DNS_SD_LIBDISPATCH 0
#endif /* ndef _DNS_SD_LIBDISPATCH */

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

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

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

/* EFI does not have stdint.h, or anything else equivalent */
#elif defined(EFI32) || defined(EFI64) || defined(EFIX64)
#include "Tiano.h"
#if !defined(_STDINT_H_)
typedef UINT8 uint8_t;
typedef INT8 int8_t;
typedef UINT16 uint16_t;
typedef INT16 int16_t;
typedef UINT32 uint32_t;
typedef INT32 int32_t;
#endif
/* Windows has its own differences */
#elif defined(_WIN32)
#include <windows.h>
#define _UNUSED
#ifndef _MSL_STDINT_H
typedef UINT8 uint8_t;
typedef INT8 int8_t;
typedef UINT16 uint16_t;
typedef INT16 int16_t;
typedef UINT32 uint32_t;
typedef INT32 int32_t;
#endif

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

#if _DNS_SD_LIBDISPATCH
#include <dispatch/dispatch.h>
#endif

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

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

struct sockaddr;

/*! @enum General flags
 * Most DNS-SD API functions and callbacks include a DNSServiceFlags parameter.
 * As a general rule, any given bit in the 32-bit flags field has a specific
 * fixed meaning, regardless of the function or callback being used. For any
 * given function or callback, typically only a subset of the possible flags are
 * meaningful, and all others should be zero. The discussion section for each
 * API call describes which flags are valid for that call and callback. In some
 * cases, for a particular call, it may be that no flags are currently defined,
 * in which case the DNSServiceFlags parameter exists purely to allow future
 * expansion. In all cases, developers should expect that in future releases, it
 * is possible that new flag values will be defined, and write code with this in
 * mind. For example, code that tests if (flags == kDNSServiceFlagsAdd) ... will
 * fail if, in a future release, another bit in the 32-bit flags field is also
 * set. The reliable way to test whether a particular bit is set is not with an
 * equality test, but with a bitwise mask: if (flags & kDNSServiceFlagsAdd) ...
 */
enum {
  kDNSServiceFlagsMoreComing = 0x1,
  /* MoreComing indicates to a callback that at least one more result is
   * queued and will be delivered following immediately after this one.
   * When the MoreComing flag is set, applications should not immediately
   * update their UI, because this can result in a great deal of ugly flickering
   * on the screen, and can waste a great deal of CPU time repeatedly updating
   * the screen with content that is then immediately erased, over and over.
   * Applications should wait until until MoreComing is not set, and then
   * update their UI when no more changes are imminent.
   * When MoreComing is not set, that doesn't mean there will be no more
   * answers EVER, just that there are no more answers immediately
   * available right now at this instant. If more answers become available
   * in the future they will be delivered as usual.
   */

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

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

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

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

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

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

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

  kDNSServiceFlagsForce = 0x800,
  /* Flag for signifying a "stronger" variant of an operation.
   * Currently defined only for DNSServiceReconfirmRecord(), where it forces a
   * record to be removed from the cache immediately, instead of querying for a
   * few seconds before concluding that the record is no longer valid and then
   * removing it. This flag should be used with caution because if a service
   * browsing PTR record is indeed still valid on the network, forcing its
   * removal will result in a user-interface flap -- the discovered service
   * instance will disappear, and then re-appear moments later.
   */

  kDNSServiceFlagsReturnIntermediates = 0x1000,
  /* Flag for returning intermediate results.
   * For example, if a query results in an authoritative NXDomain (name does not
   * exist) then that result is returned to the client. However the query is not
   * implicitly cancelled -- it remains active and if the answer subsequently
   * changes (e.g. because a VPN tunnel is subsequently established) then that
   * positive result will still be returned to the client. Similarly, if a query
   * results in a CNAME record, then in addition to following the CNAME
   * referral, the intermediate CNAME result is also returned to the client.
   * When this flag is not set, NXDomain errors are not returned, and CNAME
   * records are followed silently without informing the client of the
   * intermediate steps. (In earlier builds this flag was briefly
   * calledkDNSServiceFlagsReturnCNAME)
   */

  kDNSServiceFlagsNonBrowsable = 0x2000,
  /* A service registered with the NonBrowsable flag set can be resolved using
   * DNSServiceResolve(), but will not be discoverable using DNSServiceBrowse().
   * This is for cases where the name is actually a GUID; it is found by other
   * means; there is no end-user benefit to browsing to find a long list of
   * opaque GUIDs. Using the NonBrowsable flag creates SRV+TXT without the cost
   * of also advertising an associated PTR record.
   */

  kDNSServiceFlagsShareConnection = 0x4000,
  /* For efficiency, clients that perform many concurrent operations may want to
   * use a single Unix Domain Socket connection with the background daemon,
   * instead of having a separate connection for each independent operation. To
   * use this mode, clients first call DNSServiceCreateConnection(&MainRef) to
   * initialize the main DNSServiceRef. For each subsequent operation that is to
   * share that same connection, the client copies the MainRef, and then passes
   * the address of that copy, setting the ShareConnection flag to tell the
   * library that this DNSServiceRef is not a typical uninitialized
   * DNSServiceRef; it's a copy of an existing DNSServiceRef whose connection
   * information should be reused.
   *
   * For example:
   *
   * DNSServiceErrorType error;
   * DNSServiceRef MainRef;
   * error = DNSServiceCreateConnection(&MainRef);
   * if (error) ...
   * DNSServiceRef BrowseRef = MainRef;  // Important: COPY the primary
   * DNSServiceRef first... error = DNSServiceBrowse(&BrowseRef,
   * kDNSServiceFlagsShareConnection, ...); // then use the copy if (error) ...
   * ...
   * DNSServiceRefDeallocate(BrowseRef); // Terminate the browse operation
   * DNSServiceRefDeallocate(MainRef);   // Terminate the shared connection
   *
   * Notes:
   *
   * 1. Collective kDNSServiceFlagsMoreComing flag
   * When callbacks are invoked using a shared DNSServiceRef, the
   * kDNSServiceFlagsMoreComing flag applies collectively to *all* active
   * operations sharing the same proxy DNSServiceRef. If the MoreComing flag is
   * set it means that there are more results queued on this proxy
   * DNSServiceRef, but not necessarily more results for this particular
   * callback function. The implication of this for client programmers is that
   * when a callback is invoked with the MoreComing flag set, the code should
   * update its internal data structures with the new result, and set a variable
   * indicating that its UI needs to be updated. Then, later when a callback is
   * eventually invoked with the MoreComing flag not set, the code should update
   * *all* stale UI elements related to that shared proxy DNSServiceRef that
   * need updating, not just the UI elements related to the particular callback
   * that happened to be the last one to be invoked.
   *
   * 2. Canceling operations and kDNSServiceFlagsMoreComing
   * Whenever you cancel any operation for which you had deferred UI updates
   * waiting because of a kDNSServiceFlagsMoreComing flag, you should perform
   * those deferred UI updates. This is because, after cancelling the operation,
   * you can no longer wait for a callback *without* MoreComing set, to tell
   * you do perform your deferred UI updates (the operation has been canceled,
   * so there will be no more callbacks). An implication of the collective
   * kDNSServiceFlagsMoreComing flag for shared connections is that this
   * guideline applies more broadly -- any time you cancel an operation on
   * a shared connection, you should perform all deferred UI updates for all
   * operations sharing that connection. This is because the MoreComing flag
   * might have been referring to events coming for the operation you canceled,
   * which will now not be coming because the operation has been canceled.
   *
   * 3. Only share DNSServiceRef's created with DNSServiceCreateConnection
   * Calling DNSServiceCreateConnection(&ref) creates a special shareable
   * DNSServiceRef. DNSServiceRef's created by other calls like
   * DNSServiceBrowse() or DNSServiceResolve() cannot be shared by copying them
   * and using kDNSServiceFlagsShareConnection.
   *
   * 4. Don't Double-Deallocate
   * Calling DNSServiceRefDeallocate(ref) for a particular operation's
   * DNSServiceRef terminates just that operation. Calling
   * DNSServiceRefDeallocate(ref) for the main shared DNSServiceRef (the proxy
   * DNSServiceRef, originally created by DNSServiceCreateConnection(&ref))
   * automatically terminates the shared connection and all operations that were
   * still using it. After doing this, DO NOT then attempt to deallocate any
   * remaining subordinate DNSServiceRef's. The memory used by those subordinate
   * DNSServiceRef's has already been freed, so any attempt to do a
   * DNSServiceRefDeallocate (or any other operation) on them will result in
   * accesses to freed memory, leading to crashes or other equally undesirable
   * results.
   *
   * 5. Thread Safety
   * The dns_sd.h API does not presuppose any particular threading model, and
   * consequently does no locking of its own (which would require linking some
   * specific threading library). If client code calls API routines on the same
   * DNSServiceRef concurrently from multiple threads, it is the client's
   * responsibility to use a mutext lock or take similar appropriate precautions
   * to serialize those calls.
   */

  kDNSServiceFlagsSuppressUnusable = 0x8000,
  /*
   * This flag is meaningful only in DNSServiceQueryRecord which suppresses
   * unusable queries on the wire. If "hostname" is a wide-area unicast DNS
   * hostname (i.e. not a ".local." name) but this host has no routable IPv6
   * address, then the call will not try to look up IPv6 addresses for
   * "hostname", since any addresses it found would be unlikely to be of any use
   * anyway. Similarly, if this host has no routable IPv4 address, the call will
   * not try to look up IPv4 addresses for "hostname".
   */

  kDNSServiceFlagsTimeout = 0x10000,
  /*
   * When kDNServiceFlagsTimeout is passed to DNSServiceQueryRecord or
   * DNSServiceGetAddrInfo, the query is stopped after a certain number of
   * seconds have elapsed. The time at which the query will be stopped is
   * determined by the system and cannot be configured by the user. The query
   * will be stopped irrespective of whether a response was given earlier or
   * not. When the query is stopped, the callback will be called with an error
   * code of kDNSServiceErr_Timeout and a NULL sockaddr will be returned for
   * DNSServiceGetAddrInfo and zero length rdata will be returned for
   * DNSServiceQueryRecord.
   */

  kDNSServiceFlagsIncludeP2P = 0x20000,
  /*
   * Include P2P interfaces when kDNSServiceInterfaceIndexAny is specified.
   * By default, specifying kDNSServiceInterfaceIndexAny does not include P2P
   * interfaces.
   */
  kDNSServiceFlagsWakeOnResolve = 0x40000
  /*
   * This flag is meaningful only in DNSServiceResolve. When set, it tries to
   * send a magic packet to wake up the client.
   */
};

/* Possible protocols for DNSServiceNATPortMappingCreate(). */
enum {
  kDNSServiceProtocol_IPv4 = 0x01,
  kDNSServiceProtocol_IPv6 = 0x02,
  /* 0x04 and 0x08 reserved for future internetwork protocols */

  kDNSServiceProtocol_UDP = 0x10,
  kDNSServiceProtocol_TCP = 0x20
  /* 0x40 and 0x80 reserved for future transport protocols, e.g. SCTP [RFC 2960]
   * or DCCP [RFC 4340]. If future NAT gateways are created that support port
   * mappings for these protocols, new constants will be defined here.
   */
};

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

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

enum {
  kDNSServiceType_A = 1,           /* Host address. */
  kDNSServiceType_NS = 2,          /* Authoritative server. */
  kDNSServiceType_MD = 3,          /* Mail destination. */
  kDNSServiceType_MF = 4,          /* Mail forwarder. */
  kDNSServiceType_CNAME = 5,       /* Canonical name. */
  kDNSServiceType_SOA = 6,         /* Start of authority zone. */
  kDNSServiceType_MB = 7,          /* Mailbox domain name. */
  kDNSServiceType_MG = 8,          /* Mail group member. */
  kDNSServiceType_MR = 9,          /* Mail rename name. */
  kDNSServiceType_NULL = 10,       /* Null resource record. */
  kDNSServiceType_WKS = 11,        /* Well known service. */
  kDNSServiceType_PTR = 12,        /* Domain name pointer. */
  kDNSServiceType_HINFO = 13,      /* Host information. */
  kDNSServiceType_MINFO = 14,      /* Mailbox information. */
  kDNSServiceType_MX = 15,         /* Mail routing information. */
  kDNSServiceType_TXT = 16,        /* One or more text strings (NOT "zero or more..."). */
  kDNSServiceType_RP = 17,         /* Responsible person. */
  kDNSServiceType_AFSDB = 18,      /* AFS cell database. */
  kDNSServiceType_X25 = 19,        /* X_25 calling address. */
  kDNSServiceType_ISDN = 20,       /* ISDN calling address. */
  kDNSServiceType_RT = 21,         /* Router. */
  kDNSServiceType_NSAP = 22,       /* NSAP address. */
  kDNSServiceType_NSAP_PTR = 23,   /* Reverse NSAP lookup (deprecated). */
  kDNSServiceType_SIG = 24,        /* Security signature. */
  kDNSServiceType_KEY = 25,        /* Security key. */
  kDNSServiceType_PX = 26,         /* X.400 mail mapping. */
  kDNSServiceType_GPOS = 27,       /* Geographical position (withdrawn). */
  kDNSServiceType_AAAA = 28,       /* IPv6 Address. */
  kDNSServiceType_LOC = 29,        /* Location Information. */
  kDNSServiceType_NXT = 30,        /* Next domain (security). */
  kDNSServiceType_EID = 31,        /* Endpoint identifier. */
  kDNSServiceType_NIMLOC = 32,     /* Nimrod Locator. */
  kDNSServiceType_SRV = 33,        /* Server Selection. */
  kDNSServiceType_ATMA = 34,       /* ATM Address */
  kDNSServiceType_NAPTR = 35,      /* Naming Authority PoinTeR */
  kDNSServiceType_KX = 36,         /* Key Exchange */
  kDNSServiceType_CERT = 37,       /* Certification record */
  kDNSServiceType_A6 = 38,         /* IPv6 Address (deprecated) */
  kDNSServiceType_DNAME = 39,      /* Non-terminal DNAME (for IPv6) */
  kDNSServiceType_SINK = 40,       /* Kitchen sink (experimental) */
  kDNSServiceType_OPT = 41,        /* EDNS0 option (meta-RR) */
  kDNSServiceType_APL = 42,        /* Address Prefix List */
  kDNSServiceType_DS = 43,         /* Delegation Signer */
  kDNSServiceType_SSHFP = 44,      /* SSH Key Fingerprint */
  kDNSServiceType_IPSECKEY = 45,   /* IPSECKEY */
  kDNSServiceType_RRSIG = 46,      /* RRSIG */
  kDNSServiceType_NSEC = 47,       /* Denial of Existence */
  kDNSServiceType_DNSKEY = 48,     /* DNSKEY */
  kDNSServiceType_DHCID = 49,      /* DHCP Client Identifier */
  kDNSServiceType_NSEC3 = 50,      /* Hashed Authenticated Denial of Existence */
  kDNSServiceType_NSEC3PARAM = 51, /* Hashed Authenticated Denial of Existence */

  kDNSServiceType_HIP = 55, /* Host Identity Protocol */

  kDNSServiceType_SPF = 99,     /* Sender Policy Framework for E-Mail */
  kDNSServiceType_UINFO = 100,  /* IANA-Reserved */
  kDNSServiceType_UID = 101,    /* IANA-Reserved */
  kDNSServiceType_GID = 102,    /* IANA-Reserved */
  kDNSServiceType_UNSPEC = 103, /* IANA-Reserved */

  kDNSServiceType_TKEY = 249,  /* Transaction key */
  kDNSServiceType_TSIG = 250,  /* Transaction signature. */
  kDNSServiceType_IXFR = 251,  /* Incremental zone transfer. */
  kDNSServiceType_AXFR = 252,  /* Transfer zone of authority. */
  kDNSServiceType_MAILB = 253, /* Transfer mailbox records. */
  kDNSServiceType_MAILA = 254, /* Transfer mail agent records. */
  kDNSServiceType_ANY = 255    /* Wildcard match. */
};

/* possible error code values */
enum {
  kDNSServiceErr_NoError = 0,
  kDNSServiceErr_Unknown = -65537, /* 0xFFFE FFFF */
  kDNSServiceErr_NoSuchName = -65538,
  kDNSServiceErr_NoMemory = -65539,
  kDNSServiceErr_BadParam = -65540,
  kDNSServiceErr_BadReference = -65541,
  kDNSServiceErr_BadState = -65542,
  kDNSServiceErr_BadFlags = -65543,
  kDNSServiceErr_Unsupported = -65544,
  kDNSServiceErr_NotInitialized = -65545,
  kDNSServiceErr_AlreadyRegistered = -65547,
  kDNSServiceErr_NameConflict = -65548,
  kDNSServiceErr_Invalid = -65549,
  kDNSServiceErr_Firewall = -65550,
  kDNSServiceErr_Incompatible = -65551, /* client library incompatible with daemon */
  kDNSServiceErr_BadInterfaceIndex = -65552,
  kDNSServiceErr_Refused = -65553,
  kDNSServiceErr_NoSuchRecord = -65554,
  kDNSServiceErr_NoAuth = -65555,
  kDNSServiceErr_NoSuchKey = -65556,
  kDNSServiceErr_NATTraversal = -65557,
  kDNSServiceErr_DoubleNAT = -65558,
  kDNSServiceErr_BadTime = -65559, /* Codes up to here existed in Tiger */
  kDNSServiceErr_BadSig = -65560,
  kDNSServiceErr_BadKey = -65561,
  kDNSServiceErr_Transient = -65562,
  kDNSServiceErr_ServiceNotRunning = -65563,         /* Background daemon not running */
  kDNSServiceErr_NATPortMappingUnsupported = -65564, /* NAT doesn't support NAT-PMP or UPnP */
  kDNSServiceErr_NATPortMappingDisabled = -65565,    /* NAT supports NAT-PMP or UPnP but it's disabled by the
                                                        administrator */
  kDNSServiceErr_NoRouter = -65566,                  /* No router currently configured (probably
                                                        no network connectivity) */
  kDNSServiceErr_PollingMode = -65567,
  kDNSServiceErr_Timeout = -65568

  /* mDNS Error codes are in the range
   * FFFE FF00 (-65792) to FFFE FFFF (-65537) */
};

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

#define kDNSServiceMaxServiceName 64

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

#define kDNSServiceMaxDomainName 1009

/*
 * Notes on DNS Name Escaping
 *   -- or --
 * "Why is kDNSServiceMaxDomainName 1009, when the maximum legal domain name is
 * 256 bytes?"
 *
 * All strings used in the DNS-SD APIs are UTF-8 strings. Apart from the
 * exceptions noted below, the APIs expect the strings to be properly escaped,
 * using the conventional DNS escaping rules:
 *
 *   '\\' represents a single literal '\' in the name
 *   '\.' represents a single literal '.' in the name
 *   '\ddd', where ddd is a three-digit decimal value from 000 to 255,
 *        represents a single literal byte with that value.
 *   A bare unescaped '.' is a label separator, marking a boundary between
 * domain and subdomain.
 *
 * The exceptions, that do not use escaping, are the routines where the full
 * DNS name of a resource is broken, for convenience, into
 * servicename/regtype/domain. In these routines, the "servicename" is NOT
 * escaped. It does not need to be, since it is, by definition, just a single
 * literal string. Any characters in that string represent exactly what they
 * are. The "regtype" portion is, technically speaking, escaped, but since legal
 * regtypes are only allowed to contain letters, digits, and hyphens, there is
 * nothing to escape, so the issue is moot. The "domain" portion is also
 * escaped, though most domains in use on the public Internet today, like
 * regtypes, don't contain any characters that need to be escaped. As DNS-SD
 * becomes more popular, rich-text domains for service discovery will become
 * common, so software should be written to cope with domains with escaping.
 *
 * The servicename may be up to 63 bytes of UTF-8 text (not counting the
 * C-String terminating NULL at the end). The regtype is of the form
 * _service._tcp or _service._udp, where the "service" part is 1-15 characters,
 * which may be letters, digits, or hyphens. The domain part of the three-part
 * name may be any legal domain, providing that the resulting
 * servicename+regtype+domain name does not exceed 256 bytes.
 *
 * For most software, these issues are transparent. When browsing, the
 * discovered servicenames should simply be displayed as-is. When resolving, the
 * discovered servicename/regtype/domain are simply passed unchanged to
 * DNSServiceResolve(). When a DNSServiceResolve() succeeds, the returned
 * fullname is already in the correct format to pass to standard system DNS APIs
 * such as res_query(). For converting from servicename/regtype/domain to a
 * single properly-escaped full DNS name, the helper function
 * DNSServiceConstructFullName() is provided.
 *
 * The following (highly contrived) example illustrates the escaping process.
 * Suppose you have an service called "Dr. Smith\Dr. Johnson", of type
 * "_ftp._tcp" in subdomain "4th. Floor" of subdomain "Building 2" of domain
 * "apple.com." The full (escaped) DNS name of this service's SRV record would
 * be:
 * Dr\.\032Smith\\Dr\.\032Johnson._ftp._tcp.4th\.\032Floor.Building\0322.apple.com.
 */

/*
 * Constants for specifying an interface index
 *
 * Specific interface indexes are identified via a 32-bit unsigned integer
 * returned by the if_nametoindex() family of calls.
 *
 * If the client passes 0 for interface index, that means "do the right thing",
 * which (at present) means, "if the name is in an mDNS local multicast domain
 * (e.g. 'local.', '254.169.in-addr.arpa.', '{8,9,A,B}.E.F.ip6.arpa.') then
 * multicast on all applicable interfaces, otherwise send via unicast to the
 * appropriate DNS server." Normally, most clients will use 0 for interface
 * index to automatically get the default sensible behaviour.
 *
 * If the client passes a positive interface index, then for multicast names
 * that indicates to do the operation only on that one interface. For unicast
 * names the interface index is ignored unless kDNSServiceFlagsForceMulticast is
 * also set.
 *
 * If the client passes kDNSServiceInterfaceIndexLocalOnly when registering
 * a service, then that service will be found *only* by other local clients
 * on the same machine that are browsing using
 * kDNSServiceInterfaceIndexLocalOnly or kDNSServiceInterfaceIndexAny. If a
 * client has a 'private' service, accessible only to other processes running on
 * the same machine, this allows the client to advertise that service in a way
 * such that it does not inadvertently appear in service lists on all the other
 * machines on the network.
 *
 * If the client passes kDNSServiceInterfaceIndexLocalOnly when browsing
 * then it will find *all* records registered on that same local machine.
 * Clients explicitly wishing to discover *only* LocalOnly services can
 * accomplish this by inspecting the interfaceIndex of each service reported
 * to their DNSServiceBrowseReply() callback function, and discarding those
 * where the interface index is not kDNSServiceInterfaceIndexLocalOnly.
 *
 * kDNSServiceInterfaceIndexP2P is meaningful only in Browse, QueryRecord,
 * and Resolve operations. It should not be used in other DNSService APIs.
 *
 * - If kDNSServiceInterfaceIndexP2P is passed to DNSServiceBrowse or
 *   DNSServiceQueryRecord, it restricts the operation to P2P.
 *
 * - If kDNSServiceInterfaceIndexP2P is passed to DNSServiceResolve, it is
 *   mapped internally to kDNSServiceInterfaceIndexAny, because resolving
 *   a P2P service may attach and/or enable an interface whose index is not
 *   known a priori. The resolve callback will indicate the index of the
 *   interface via which the service can be accessed.
 *
 * If applications pass kDNSServiceInterfaceIndexAny to DNSServiceBrowse
 * or DNSServiceQueryRecord, they must set the kDNSServiceFlagsIncludeP2P flag
 * to include P2P. In this case, if a service instance or the record being
 * queried is found over P2P, the resulting ADD event will indicate
 * kDNSServiceInterfaceIndexP2P as the interface index.
 */

#define kDNSServiceInterfaceIndexAny 0
#define kDNSServiceInterfaceIndexLocalOnly ((uint32_t)-1)
#define kDNSServiceInterfaceIndexUnicast ((uint32_t)-2)
#define kDNSServiceInterfaceIndexP2P ((uint32_t)-3)

typedef uint32_t DNSServiceFlags;
typedef uint32_t DNSServiceProtocol;
typedef int32_t DNSServiceErrorType;

/*********************************************************************************************
 *
 * Version checking
 *
 *********************************************************************************************/

/* DNSServiceGetProperty() Parameters:
 *
 * property:        The requested property.
 *                  Currently the only property defined is
 * kDNSServiceProperty_DaemonVersion.
 *
 * result:          Place to store result.
 *                  For retrieving DaemonVersion, this should be the address of
 * a uint32_t.
 *
 * size:            Pointer to uint32_t containing size of the result location.
 *                  For retrieving DaemonVersion, this should be
 * sizeof(uint32_t). On return the uint32_t is updated to the size of the data
 * returned. For DaemonVersion, the returned size is always sizeof(uint32_t),
 * but future properties could be defined which return variable-sized results.
 *
 * return value:    Returns kDNSServiceErr_NoError on success, or
 * kDNSServiceErr_ServiceNotRunning if the daemon (or "system service" on
 * Windows) is not running.
 */

DNSServiceErrorType DNSSD_API DNSServiceGetProperty(const char *property, /* Requested property (i.e.
                                                                             kDNSServiceProperty_DaemonVersion) */
                                                    void *result,         /* Pointer to place to store result */
                                                    uint32_t *size        /* size of result location */
);

/*
 * When requesting kDNSServiceProperty_DaemonVersion, the result pointer must
 * point to a 32-bit unsigned integer, and the size parameter must be set to
 * sizeof(uint32_t).
 *
 * On return, the 32-bit unsigned integer contains the version number, formatted
 * as follows: Major part of the build number * 10000 + minor part of the build
 * number *   100
 *
 * For example, Mac OS X 10.4.9 has mDNSResponder-108.4, which would be
 * represented as version 1080400. This allows applications to do simple
 * greater-than and less-than comparisons: e.g. an application that requires at
 * least mDNSResponder-108.4 can check:
 *
 *   if (version >= 1080400) ...
 *
 * Example usage:
 *
 * uint32_t version;
 * uint32_t size = sizeof(version);
 * DNSServiceErrorType err =
 * DNSServiceGetProperty(kDNSServiceProperty_DaemonVersion, &version, &size); if
 * (!err) printf("Bonjour version is %d.%d\n", version / 10000, version / 100 %
 * 100);
 */

#define kDNSServiceProperty_DaemonVersion "DaemonVersion"

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

/* DNSServiceRefSockFD()
 *
 * Access underlying Unix domain socket for an initialized DNSServiceRef.
 * The DNS Service Discovery implementation uses this socket to communicate
 * between the client and the mDNSResponder daemon. The application MUST NOT
 * directly read from or write to this socket. Access to the socket is provided
 * so that it can be used as a kqueue event source, a CFRunLoop event source, in
 * a select() loop, etc. When the underlying event management subsystem (kqueue/
 * select/CFRunLoop etc.) indicates to the client that data is available for
 * reading on the socket, the client should call DNSServiceProcessResult(),
 * which will extract the daemon's reply from the socket, and pass it to the
 * appropriate application callback. By using a run loop or select(), results
 * from the daemon can be processed asynchronously. Alternatively, a client can
 * choose to fork a thread and have it loop calling
 * "DNSServiceProcessResult(ref);" If DNSServiceProcessResult() is called when
 * no data is available for reading on the socket, it will block until data does
 * become available, and then process the data and return to the caller. When
 * data arrives on the socket, the client is responsible for calling
 * DNSServiceProcessResult(ref) in a timely fashion -- if the client allows a
 * large backlog of data to build up the daemon may terminate the connection.
 *
 * sdRef:           A DNSServiceRef initialized by any of the DNSService calls.
 *
 * return value:    The DNSServiceRef's underlying socket descriptor, or -1 on
 *                  error.
 */

int DNSSD_API DNSServiceRefSockFD(DNSServiceRef sdRef);

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

DNSServiceErrorType DNSSD_API DNSServiceProcessResult(DNSServiceRef sdRef);

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

void DNSSD_API DNSServiceRefDeallocate(DNSServiceRef sdRef);

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

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

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

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

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

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

/* Register a service that is discovered via Browse() and Resolve() calls.
 *
 * DNSServiceRegisterReply() Callback Parameters:
 *
 * sdRef:           The DNSServiceRef initialized by DNSServiceRegister().
 *
 * flags:           When a name is successfully registered, the callback will be
 *                  invoked with the kDNSServiceFlagsAdd flag set. When
 * Wide-Area DNS-SD is in use, it is possible for a single service to get more
 * than one success callback (e.g. one in the "local" multicast DNS domain, and
 * another in a wide-area unicast DNS domain). If a successfully-registered name
 * later suffers a name conflict or similar problem and has to be deregistered,
 * the callback will be invoked with the kDNSServiceFlagsAdd flag not set. The
 * callback is *not* invoked in the case where the caller explicitly terminates
 *                  the service registration by calling
 * DNSServiceRefDeallocate(ref);
 *
 * errorCode:       Will be kDNSServiceErr_NoError on success, otherwise will
 *                  indicate the failure that occurred (including name
 * conflicts, if the kDNSServiceFlagsNoAutoRename flag was used when
 * registering.) Other parameters are undefined if errorCode is nonzero.
 *
 * name:            The service name registered (if the application did not
 * specify a name in DNSServiceRegister(), this indicates what name was
 * automatically chosen).
 *
 * regtype:         The type of service registered, as it was passed to the
 * callout.
 *
 * domain:          The domain on which the service was registered (if the
 * application did not specify a domain in DNSServiceRegister(), this indicates
 * the default domain on which the service was registered).
 *
 * context:         The context pointer that was passed to the callout.
 *
 */

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

/* DNSServiceRegister() Parameters:
 *
 * sdRef:           A pointer to an uninitialized DNSServiceRef. If the call
 * succeeds then it initializes the DNSServiceRef, returns
 * kDNSServiceErr_NoError, and the registration will remain active indefinitely
 * until the client terminates it by passing this DNSServiceRef to
 * DNSServiceRefDeallocate().
 *
 * interfaceIndex:  If non-zero, specifies the interface on which to register
 * the service (the index for a given interface is determined via the
 * if_nametoindex() family of calls.) Most applications will pass 0 to register
 * on all available interfaces. See "Constants for specifying an interface
 * index" for more details.
 *
 * flags:           Indicates the renaming behavior on name conflict (most
 * applications will pass 0). See flag definitions above for details.
 *
 * name:            If non-NULL, specifies the service name to be registered.
 *                  Most applications will not specify a name, in which case the
 * computer name is used (this name is communicated to the client via the
 * callback). If a name is specified, it must be 1-63 bytes of UTF-8 text. If
 * the name is longer than 63 bytes it will be automatically truncated to a
 * legal length, unless the NoAutoRename flag is set, in which case
 * kDNSServiceErr_BadParam will be returned.
 *
 * regtype:         The service type followed by the protocol, separated by a
 * dot (e.g. "_ftp._tcp"). The service type must be an underscore, followed by
 * 1-15 characters, which may be letters, digits, or hyphens. The transport
 * protocol must be "_tcp" or "_udp". New service types should be registered at
 * <http://www.dns-sd.org/ServiceTypes.html>.
 *
 *                  Additional subtypes of the primary service type (where a
 * service type has defined subtypes) follow the primary service type in a
 *                  comma-separated list, with no additional spaces, e.g.
 *                      "_primarytype._tcp,_subtype1,_subtype2,_subtype3"
 *                  Subtypes provide a mechanism for filtered browsing: A client
 * browsing for "_primarytype._tcp" will discover all instances of this type; a
 * client browsing for "_primarytype._tcp,_subtype2" will discover only those
 * instances that were registered with "_subtype2" in their list of registered
 * subtypes.
 *
 *                  The subtype mechanism can be illustrated with some examples
 * using the dns-sd command-line tool:
 *
 *                  % dns-sd -R Simple _test._tcp "" 1001 &
 *                  % dns-sd -R Better _test._tcp,HasFeatureA "" 1002 &
 *                  % dns-sd -R Best   _test._tcp,HasFeatureA,HasFeatureB ""
 * 1003 &
 *
 *                  Now:
 *                  % dns-sd -B _test._tcp             # will find all three
 * services % dns-sd -B _test._tcp,HasFeatureA # finds "Better" and "Best" %
 * dns-sd -B _test._tcp,HasFeatureB # finds only "Best"
 *
 *                  Subtype labels may be up to 63 bytes long, and may contain
 * any eight- bit byte values, including zero bytes. However, due to the nature
 * of using a C-string-based API, conventional DNS escaping must be used for
 *                  dots ('.'), commas (','), backslashes ('\') and zero bytes,
 * as shown below:
 *
 *                  % dns-sd -R Test
 * '_test._tcp,s\.one,s\,two,s\\three,s\000four' local 123
 *
 * domain:          If non-NULL, specifies the domain on which to advertise the
 * service. Most applications will not specify a domain, instead automatically
 *                  registering in the default domain(s).
 *
 * host:            If non-NULL, specifies the SRV target host name. Most
 * applications will not specify a host, instead automatically using the
 * machine's default host name(s). Note that specifying a non-NULL host does NOT
 *                  attach an address record for that host - the application is
 * responsible for ensuring that the appropriate address record exists, or
 * creating it via DNSServiceRegisterRecord().
 *
 * port:            The port, in network byte order, on which the service
 * accepts connections. Pass 0 for a "placeholder" service (i.e. a service that
 * will not be discovered by browsing, but will cause a name conflict if another
 * client tries to register that same name). Most clients will not use
 * placeholder services.
 *
 * txtLen:          The length of the txtRecord, in bytes. Must be zero if the
 * txtRecord is NULL.
 *
 * txtRecord:       The TXT record rdata. A non-NULL txtRecord MUST be a
 * properly formatted DNS TXT record, i.e. <length byte> <data> <length byte>
 * <data> ... Passing NULL for the txtRecord is allowed as a synonym for
 * txtLen=1, txtRecord="", i.e. it creates a TXT record of length one containing
 * a single empty string. RFC 1035 doesn't allow a TXT record to contain *zero*
 * strings, so a single empty string is the smallest legal DNS TXT record. As
 * with the other parameters, the DNSServiceRegister call copies the txtRecord
 *                  data; e.g. if you allocated the storage for the txtRecord
 * parameter with malloc() then you can safely free that memory right after the
 * DNSServiceRegister call returns.
 *
 * callBack:        The function to be called when the registration completes or
 * asynchronously fails. The client MAY pass NULL for the callback -  The client
 * will NOT be notified of the default values picked on its behalf, and the
 * client will NOT be notified of any asynchronous errors (e.g. out of memory
 * errors, etc.) that may prevent the registration of the service. The client
 * may NOT pass the NoAutoRename flag if the callback is NULL. The client may
 * still deregister the service at any time via DNSServiceRefDeallocate().
 *
 * context:         An application context pointer which is passed to the
 * callback function (may be NULL).
 *
 * return value:    Returns kDNSServiceErr_NoError on success (any subsequent,
 * asynchronous errors are delivered to the callback), otherwise returns an
 * error code indicating the error that occurred (the callback is never invoked
 * and the DNSServiceRef is not initialized).
 */

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

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

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

/* DNSServiceUpdateRecord
 *
 * Update a registered resource record. The record must either be:
 *   - The primary txt record of a service registered via DNSServiceRegister()
 *   - A record added to a registered service via DNSServiceAddRecord()
 *   - An individual record registered by DNSServiceRegisterRecord()
 *
 * Parameters:
 *
 * sdRef:           A DNSServiceRef that was initialized by DNSServiceRegister()
 *                  or DNSServiceCreateConnection().
 *
 * RecordRef:       A DNSRecordRef initialized by DNSServiceAddRecord, or NULL
 * to update the service's primary txt record.
 *
 * flags:           Currently ignored, reserved for future use.
 *
 * rdlen:           The length, in bytes, of the new rdata.
 *
 * rdata:           The new rdata to be contained in the updated resource
 * record.
 *
 * ttl:             The time to live of the updated resource record, in seconds.
 *                  Most clients should pass 0 to indicate that the system
 * should select a sensible default value.
 *
 * return value:    Returns kDNSServiceErr_NoError on success, otherwise returns
 * an error code indicating the error that occurred.
 */

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

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

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

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

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

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

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

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

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

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

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

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

/*********************************************************************************************
 *
 *  Querying Individual Specific Records
 *
 *********************************************************************************************/

/* DNSServiceQueryRecord
 *
 * Query for an arbitrary DNS record.
 *
 * DNSServiceQueryRecordReply() Callback Parameters:
 *
 * sdRef:           The DNSServiceRef initialized by DNSServiceQueryRecord().
 *
 * flags:           Possible values are kDNSServiceFlagsMoreComing and
 *                  kDNSServiceFlagsAdd. The Add flag is NOT set for PTR records
 *                  with a ttl of 0, i.e. "Remove" events.
 *
 * interfaceIndex:  The interface on which the query was resolved (the index for
 * a given interface is determined via the if_nametoindex() family of calls).
 *                  See "Constants for specifying an interface index" for more
 * details.
 *
 * errorCode:       Will be kDNSServiceErr_NoError on success, otherwise will
 *                  indicate the failure that occurred. Other parameters are
 * undefined if errorCode is nonzero.
 *
 * fullname:        The resource record's full domain name.
 *
 * rrtype:          The resource record's type (e.g. kDNSServiceType_PTR,
 * kDNSServiceType_SRV, etc)
 *
 * rrclass:         The class of the resource record (usually
 * kDNSServiceClass_IN).
 *
 * rdlen:           The length, in bytes, of the resource record rdata.
 *
 * rdata:           The raw rdata of the resource record.
 *
 * ttl:             If the client wishes to cache the result for performance
 * reasons, the TTL indicates how long the client may legitimately hold onto
 *                  this result, in seconds. After the TTL expires, the client
 * should consider the result no longer valid, and if it requires this data
 *                  again, it should be re-fetched with a new query. Of course,
 * this only applies to clients that cancel the asynchronous operation when they
 * get a result. Clients that leave the asynchronous operation running can
 * safely assume that the data remains valid until they get another callback
 * telling them otherwise.
 *
 * context:         The context pointer that was passed to the callout.
 *
 */

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

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

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

/*********************************************************************************************
 *
 *  Unified lookup of both IPv4 and IPv6 addresses for a fully qualified
 *hostname
 *
 *********************************************************************************************/

/* DNSServiceGetAddrInfo
 *
 * Queries for the IP address of a hostname by using either Multicast or Unicast
 * DNS.
 *
 * DNSServiceGetAddrInfoReply() parameters:
 *
 * sdRef:           The DNSServiceRef initialized by DNSServiceGetAddrInfo().
 *
 * flags:           Possible values are kDNSServiceFlagsMoreComing and
 *                  kDNSServiceFlagsAdd.
 *
 * interfaceIndex:  The interface to which the answers pertain.
 *
 * errorCode:       Will be kDNSServiceErr_NoError on success, otherwise will
 *                  indicate the failure that occurred.  Other parameters are
 *                  undefined if errorCode is nonzero.
 *
 * hostname:        The fully qualified domain name of the host to be queried
 * for.
 *
 * address:         IPv4 or IPv6 address.
 *
 * ttl:             If the client wishes to cache the result for performance
 * reasons, the TTL indicates how long the client may legitimately hold onto
 *                  this result, in seconds. After the TTL expires, the client
 * should consider the result no longer valid, and if it requires this data
 *                  again, it should be re-fetched with a new query. Of course,
 * this only applies to clients that cancel the asynchronous operation when they
 * get a result. Clients that leave the asynchronous operation running can
 * safely assume that the data remains valid until they get another callback
 * telling them otherwise.
 *
 * context:         The context pointer that was passed to the callout.
 *
 */

typedef void(DNSSD_API *DNSServiceGetAddrInfoReply)(DNSServiceRef sdRef, DNSServiceFlags flags, uint32_t interfaceIndex,
                                                    DNSServiceErrorType errorCode, const char *hostname,
                                                    const struct sockaddr *address, uint32_t ttl, void *context);

/* DNSServiceGetAddrInfo() Parameters:
 *
 * sdRef:           A pointer to an uninitialized DNSServiceRef. If the call
 * succeeds then it initializes the DNSServiceRef, returns
 * kDNSServiceErr_NoError, and the query begins and will last indefinitely until
 * the client terminates the query by passing this DNSServiceRef to
 * DNSServiceRefDeallocate().
 *
 * flags:           kDNSServiceFlagsForceMulticast or
 * kDNSServiceFlagsLongLivedQuery. Pass kDNSServiceFlagsLongLivedQuery to attach
 * a "long-lived" unicast query in a non-local domain. Without setting this
 * flag, unicast queries will be one-shot - that is, only answers available at
 * the time of the call will be returned. By setting this flag, answers
 * (including Add and Remove events) that become available after the initial
 * call is made will generate callbacks. This flag has no effect on link-local
 * multicast queries.
 *
 * interfaceIndex:  The interface on which to issue the query.  Passing 0 causes
 * the query to be sent on all active interfaces via Multicast or the primary
 * interface via Unicast.
 *
 * protocol:        Pass in kDNSServiceProtocol_IPv4 to look up IPv4 addresses,
 * or kDNSServiceProtocol_IPv6 to look up IPv6 addresses, or both to look up
 * both kinds. If neither flag is set, the system will apply an intelligent
 * heuristic, which is (currently) that it will attempt to look up both, except:
 *
 *                   * If "hostname" is a wide-area unicast DNS hostname (i.e.
 * not a ".local." name) but this host has no routable IPv6 address, then the
 * call will not try to look up IPv6 addresses for "hostname", since any
 * addresses it found would be unlikely to be of any use anyway. Similarly, if
 * this host has no routable IPv4 address, the call will not try to look up IPv4
 * addresses for "hostname".
 *
 * hostname:        The fully qualified domain name of the host to be queried
 * for.
 *
 * callBack:        The function to be called when the query succeeds or fails
 * asynchronously.
 *
 * context:         An application context pointer which is passed to the
 * callback function (may be NULL).
 *
 * return value:    Returns kDNSServiceErr_NoError on success (any subsequent,
 * asynchronous errors are delivered to the callback), otherwise returns an
 * error code indicating the error that occurred.
 */

DNSServiceErrorType DNSSD_API DNSServiceGetAddrInfo(DNSServiceRef *sdRef, DNSServiceFlags flags,
                                                    uint32_t interfaceIndex, DNSServiceProtocol protocol,
                                                    const char *hostname, DNSServiceGetAddrInfoReply callBack,
                                                    void *context /* may be NULL */
);

/*********************************************************************************************
 *
 *  Special Purpose Calls:
 *  DNSServiceCreateConnection(), DNSServiceRegisterRecord(),
 *DNSServiceReconfirmRecord() (most applications will not use these)
 *
 *********************************************************************************************/

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

DNSServiceErrorType DNSSD_API DNSServiceCreateConnection(DNSServiceRef *sdRef);

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

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

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

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

/* DNSServiceReconfirmRecord
 *
 * Instruct the daemon to verify the validity of a resource record that appears
 * to be out of date (e.g. because TCP connection to a service's target failed.)
 * Causes the record to be flushed from the daemon's cache (as well as all other
 * daemons' caches on the network) if the record is determined to be invalid.
 * Use this routine conservatively. Reconfirming a record necessarily consumes
 * network bandwidth, so this should not be done indiscriminately.
 *
 * Parameters:
 *
 * flags:           Pass kDNSServiceFlagsForce to force immediate deletion of
 * record, instead of after some number of reconfirmation queries have gone
 * unanswered.
 *
 * interfaceIndex:  Specifies the interface of the record in question.
 *                  The caller must specify the interface.
 *                  This API (by design) causes increased network traffic, so it
 * requires the caller to be precise about which record should be reconfirmed.
 *                  It is not possible to pass zero for the interface index to
 * perform a "wildcard" reconfirmation, where *all* matching records are
 * reconfirmed.
 *
 * fullname:        The resource record's full domain name.
 *
 * rrtype:          The resource record's type (e.g. kDNSServiceType_PTR,
 * kDNSServiceType_SRV, etc)
 *
 * rrclass:         The class of the resource record (usually
 * kDNSServiceClass_IN).
 *
 * rdlen:           The length, in bytes, of the resource record rdata.
 *
 * rdata:           The raw rdata of the resource record.
 *
 */

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

/*********************************************************************************************
 *
 *  NAT Port Mapping
 *
 *********************************************************************************************/

/* DNSServiceNATPortMappingCreate
 *
 * Request a port mapping in the NAT gateway, which maps a port on the local
 * machine to an external port on the NAT. The NAT should support either the
 * NAT-PMP or the UPnP IGD protocol for this API to create a successful mapping.
 *
 * The port mapping will be renewed indefinitely until the client process exits,
 * or explicitly terminates the port mapping request by calling
 * DNSServiceRefDeallocate(). The client callback will be invoked, informing the
 * client of the NAT gateway's external IP address and the external port that
 * has been allocated for this client. The client should then record this
 * external IP address and port using whatever directory service mechanism it is
 * using to enable peers to connect to it. (Clients advertising services using
 * Wide-Area DNS-SD DO NOT need to use this API
 * -- when a client calls DNSServiceRegister() NAT mappings are automatically
 * created and the external IP address and port for the service are recorded in
 * the global DNS. Only clients using some directory mechanism other than
 * Wide-Area DNS-SD need to use this API to explicitly map their own ports.)
 *
 * It's possible that the client callback could be called multiple times, for
 * example if the NAT gateway's IP address changes, or if a configuration change
 * results in a different external port being mapped for this client. Over the
 * lifetime of any long-lived port mapping, the client should be prepared to
 * handle these notifications of changes in the environment, and should update
 * its recorded address and/or port as appropriate.
 *
 * NOTE: There are two unusual aspects of how the DNSServiceNATPortMappingCreate
 * API works, which were intentionally designed to help simplify client code:
 *
 *  1. It's not an error to request a NAT mapping when the machine is not behind
 * a NAT gateway. In other NAT mapping APIs, if you request a NAT mapping and
 * the machine is not behind a NAT gateway, then the API returns an error code
 * -- it can't get you a NAT mapping if there's no NAT gateway. The
 * DNSServiceNATPortMappingCreate API takes a different view. Working out
 *     whether or not you need a NAT mapping can be tricky and non-obvious,
 * particularly on a machine with multiple active network interfaces. Rather
 * than make every client recreate this logic for deciding whether a NAT mapping
 * is required, the PortMapping API does that work for you. If the client calls
 * the PortMapping API when the machine already has a routable public IP
 * address, then instead of complaining about it and giving an error, the
 * PortMapping API just invokes your callback, giving the machine's public
 * address and your own port number. This means you don't need to write code to
 * work out whether your client needs to call the PortMapping API -- just call
 * it anyway, and if it wasn't necessary, no harm is done:
 *
 *     - If the machine already has a routable public IP address, then your
 * callback will just be invoked giving your own address and port.
 *     - If a NAT mapping is required and obtained, then your callback will be
 * invoked giving you the external address and port.
 *     - If a NAT mapping is required but not obtained from the local NAT
 * gateway, or the machine has no network connectivity, then your callback will
 * be invoked giving zero address and port.
 *
 *  2. In other NAT mapping APIs, if a laptop computer is put to sleep and woken
 * up on a new network, it's the client's job to notice this, and work out
 * whether a NAT mapping is required on the new network, and make a new NAT
 * mapping request if necessary. The DNSServiceNATPortMappingCreate API does
 * this for you, automatically. The client just needs to make one call to the
 * PortMapping API, and its callback will be invoked any time the mapping state
 * changes. This property complements point (1) above. If the client didn't make
 * a NAT mapping request just because it determined that one was not required at
 * that particular moment in time, the client would then have to monitor for
 * network state changes to determine if a NAT port mapping later became
 * necessary. By unconditionally making a NAT mapping request, even when a NAT
 * mapping not to be necessary, the PortMapping API will then begin monitoring
 * network state changes on behalf of the client, and if a NAT mapping later
 * becomes necessary, it will automatically attach a NAT mapping and inform the
 * client with a new callback giving the new address and port information.
 *
 * DNSServiceNATPortMappingReply() parameters:
 *
 * sdRef:           The DNSServiceRef initialized by
 * DNSServiceNATPortMappingCreate().
 *
 * flags:           Currently unused, reserved for future use.
 *
 * interfaceIndex:  The interface through which the NAT gateway is reached.
 *
 * errorCode:       Will be kDNSServiceErr_NoError on success.
 *                  Will be kDNSServiceErr_DoubleNAT when the NAT gateway is
 * itself behind one or more layers of NAT, in which case the other parameters
 * have the defined values. For other failures, will indicate the failure that
 * occurred, and the other parameters are undefined.
 *
 * externalAddress: Four byte IPv4 address in network byte order.
 *
 * protocol:        Will be kDNSServiceProtocol_UDP or kDNSServiceProtocol_TCP
 * or both.
 *
 * internalPort:    The port on the local machine that was mapped.
 *
 * externalPort:    The actual external port in the NAT gateway that was mapped.
 *                  This is likely to be different than the requested external
 * port.
 *
 * ttl:             The lifetime of the NAT port mapping created on the gateway.
 *                  This controls how quickly stale mappings will be
 * garbage-collected if the client machine crashes, suffers a power failure, is
 * disconnected from the network, or suffers some other unfortunate demise which
 *                  causes it to vanish without explicitly removing its NAT port
 * mapping. It's possible that the ttl value will differ from the requested ttl
 * value.
 *
 * context:         The context pointer that was passed to the callout.
 *
 */

typedef void(DNSSD_API *DNSServiceNATPortMappingReply)(
    DNSServiceRef sdRef, DNSServiceFlags flags, uint32_t interfaceIndex, DNSServiceErrorType errorCode,
    uint32_t externalAddress,                           /* four byte IPv4 address in network byte order */
    DNSServiceProtocol protocol, uint16_t internalPort, /* In network byte order */
    uint16_t externalPort,                              /* In network byte order and may be different than
                                                           the requested port */
    uint32_t ttl,                                       /* may be different than the requested ttl */
    void *context);

/* DNSServiceNATPortMappingCreate() Parameters:
 *
 * sdRef:           A pointer to an uninitialized DNSServiceRef. If the call
 * succeeds then it initializes the DNSServiceRef, returns
 * kDNSServiceErr_NoError, and the nat port mapping will last indefinitely until
 * the client terminates the port mapping request by passing this DNSServiceRef
 * to DNSServiceRefDeallocate().
 *
 * flags:           Currently ignored, reserved for future use.
 *
 * interfaceIndex:  The interface on which to attach port mappings in a NAT
 * gateway. Passing 0 causes the port mapping request to be sent on the primary
 * interface.
 *
 * protocol:        To request a port mapping, pass in kDNSServiceProtocol_UDP,
 * or kDNSServiceProtocol_TCP, or (kDNSServiceProtocol_UDP |
 * kDNSServiceProtocol_TCP) to map both. The local listening port number must
 * also be specified in the internalPort parameter. To just discover the NAT
 * gateway's external IP address, pass zero for protocol, internalPort,
 * externalPort and ttl.
 *
 * internalPort:    The port number in network byte order on the local machine
 * which is listening for packets.
 *
 * externalPort:    The requested external port in network byte order in the NAT
 * gateway that you would like to map to the internal port. Pass 0 if you don't
 * care which external port is chosen for you.
 *
 * ttl:             The requested renewal period of the NAT port mapping, in
 * seconds. If the client machine crashes, suffers a power failure, is
 * disconnected from the network, or suffers some other unfortunate demise which
 * causes it to vanish unexpectedly without explicitly removing its NAT port
 * mappings, then the NAT gateway will garbage-collect old stale NAT port
 * mappings when their lifetime expires. Requesting a short TTL causes such
 * orphaned mappings to be garbage-collected more promptly, but consumes system
 * resources and network bandwidth with frequent renewal packets to keep the
 * mapping from expiring. Requesting a long TTL is more efficient on the
 * network, but in the event of the client vanishing, stale NAT port mappings
 * will not be garbage-collected as quickly. Most clients should pass 0 to use a
 * system-wide default value.
 *
 * callBack:        The function to be called when the port mapping request
 * succeeds or fails asynchronously.
 *
 * context:         An application context pointer which is passed to the
 * callback function (may be NULL).
 *
 * return value:    Returns kDNSServiceErr_NoError on success (any subsequent,
 * asynchronous errors are delivered to the callback), otherwise returns an
 * error code indicating the error that occurred.
 *
 *                  If you don't actually want a port mapped, and are just
 * calling the API because you want to find out the NAT's external IP address
 * (e.g. for UI display) then pass zero for protocol, internalPort, externalPort
 * and ttl.
 */

DNSServiceErrorType DNSSD_API DNSServiceNATPortMappingCreate(DNSServiceRef *sdRef, DNSServiceFlags flags,
                                                             uint32_t interfaceIndex,
                                                             DNSServiceProtocol protocol, /* TCP and/or UDP          */
                                                             uint16_t internalPort,       /* network byte order      */
                                                             uint16_t externalPort,       /* network byte order      */
                                                             uint32_t ttl,                /* time to live in seconds */
                                                             DNSServiceNATPortMappingReply callBack,
                                                             void *context /* may be NULL */
);

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

/* DNSServiceConstructFullName()
 *
 * Concatenate a three-part domain name (as returned by the above callbacks)
 * into a properly-escaped full domain name. Note that callbacks in the above
 * functions ALREADY ESCAPE strings where necessary.
 *
 * Parameters:
 *
 * fullName:        A pointer to a buffer that where the resulting full domain
 * name is to be written. The buffer must be kDNSServiceMaxDomainName (1009)
 * bytes in length to accommodate the longest legal domain name without buffer
 * overrun.
 *
 * service:         The service name - any dots or backslashes must NOT be
 * escaped. May be NULL (to construct a PTR record name, e.g.
 *                  "_ftp._tcp.apple.com.").
 *
 * regtype:         The service type followed by the protocol, separated by a
 * dot (e.g. "_ftp._tcp").
 *
 * domain:          The domain name, e.g. "apple.com.". Literal dots or
 * backslashes, if any, must be escaped, e.g. "1st\. Floor.apple.com."
 *
 * return value:    Returns kDNSServiceErr_NoError (0) on success,
 * kDNSServiceErr_BadParam on error.
 *
 */

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

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

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

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

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

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

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

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

void DNSSD_API TXTRecordDeallocate(TXTRecordRef *txtRecord);

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

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

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

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

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

uint16_t DNSSD_API TXTRecordGetLength(const TXTRecordRef *txtRecord);

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

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

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

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

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

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

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

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

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

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

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

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

#if _DNS_SD_LIBDISPATCH
/*
 * DNSServiceSetDispatchQueue
 *
 * Allows you to schedule a DNSServiceRef on a serial dispatch queue for
 * receiving asynchronous callbacks.  It's the clients responsibility to ensure
 * that the provided dispatch queue is running.
 *
 * A typical application that uses CFRunLoopRun or dispatch_main on its main
 * thread will usually schedule DNSServiceRefs on its main queue (which is
 * always a serial queue) using "DNSServiceSetDispatchQueue(sdref,
 * dispatch_get_main_queue());"
 *
 * If there is any error during the processing of events, the application
 * callback will be called with an error code. For shared connections, each
 * subordinate DNSServiceRef will get its own error callback. Currently these
 * error callbacks only happen if the mDNSResponder daemon is manually
 * terminated or crashes, and the error code in this case is
 * kDNSServiceErr_ServiceNotRunning. The application must call
 * DNSServiceRefDeallocate to free the DNSServiceRef when it gets such an error
 * code. These error callbacks are rare and should not normally happen on
 * customer machines, but application code should be written defensively to
 * handle such error callbacks gracefully if they occur.
 *
 * After using DNSServiceSetDispatchQueue on a DNSServiceRef, calling
 * DNSServiceProcessResult on the same DNSServiceRef will result in undefined
 * behavior and should be avoided.
 *
 * Once the application successfully schedules a DNSServiceRef on a serial
 * dispatch queue using DNSServiceSetDispatchQueue, it cannot remove the
 * DNSServiceRef from the dispatch queue, or use DNSServiceSetDispatchQueue a
 * second time to schedule the DNSServiceRef onto a different serial dispatch
 * queue. Once scheduled onto a dispatch queue a DNSServiceRef will deliver
 * events to that queue until the application no longer requires that operation
 * and terminates it using DNSServiceRefDeallocate.
 *
 * service:         DNSServiceRef that was allocated and returned to the
 * application, when the application calls one of the DNSService API.
 *
 * queue:           dispatch queue where the application callback will be
 * scheduled
 *
 * return value:    Returns kDNSServiceErr_NoError on success.
 *                  Returns kDNSServiceErr_NoMemory if it cannot attach a
 * dispatch source Returns kDNSServiceErr_BadParam if the service param is
 * invalid or the queue param is invalid
 */

DNSServiceErrorType DNSSD_API DNSServiceSetDispatchQueue(DNSServiceRef service, dispatch_queue_t queue);
#endif //_DNS_SD_LIBDISPATCH

#ifdef __APPLE_API_PRIVATE

#define kDNSServiceCompPrivateDNS "PrivateDNS"
#define kDNSServiceCompMulticastDNS "MulticastDNS"

#endif //__APPLE_API_PRIVATE

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

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

#ifdef __cplusplus
}
#endif

#endif /* _DNS_SD_H */
