mDNSCore/mDNSPlatformFunctions.h

   1 // ***************************************************************************
   2 // Support functions which must be provided by each set of specific PlatformSupport files
   3
   4 // mDNSPlatformInit() typically opens a communication endpoint, and starts listening for mDNS packets.
   5 // When Setup is complete, the callback is called.
   6 // mDNSPlatformSendUDP() sends one UDP packet
   7 // When a packet is received, the PlatformSupport code calls mDNSCoreReceive()
   8 // mDNSPlatformScheduleTask() indicates that a timer should be set,
   9 // and mDNSCoreTask() should be called when the timer expires
  10 // mDNSPlatformClose() tidies up on exit
  11
  12 #ifdef  __cplusplus
  13         extern "C" {
  14 #endif
  15
  16 // ***************************************************************************
  17 // DNS protocol message format
  18
  19 typedef struct
  20         {
  21         mDNSOpaque16 id;
  22         mDNSOpaque16 flags;
  23         mDNSu16 numQuestions;
  24         mDNSu16 numAnswers;
  25         mDNSu16 numAuthorities;
  26         mDNSu16 numAdditionals;
  27         } DNSMessageHeader;
  28
  29 // We can send and receive packets up to 9000 bytes (Ethernet Jumbo Frame size, if that ever becomes widely used)
  30 // However, in the normal case we try to limit packets to 1500 bytes so that we don't get IP fragmentation on standard Ethernet
  31 #define AbsoluteMaxDNSMessageData 8960
  32 #define NormalMaxDNSMessageData 1460
  33 typedef struct
  34         {
  35         DNSMessageHeader h;                                             // Note: Size 12 bytes
  36         mDNSu8 data[AbsoluteMaxDNSMessageData]; // 20 (IP) + 8 (UDP) + 12 (header) + 8960 (data) = 9000
  37         } DNSMessage;
  38
  39 // ***************************************************************************
  40 // Functions
  41
  42 // Every platform support module must provide the following functions
  43 extern mStatus  mDNSPlatformInit   (mDNS *const m);
  44 extern void     mDNSPlatformClose  (mDNS *const m);
  45 extern mStatus  mDNSPlatformSendUDP(const mDNS *const m, const DNSMessage *const msg, const mDNSu8 *const end,
  46         mDNSIPAddr src, mDNSIPPort srcport, mDNSIPAddr dst, mDNSIPPort dstport);
  47
  48 extern void     mDNSPlatformScheduleTask(const mDNS *const m, mDNSs32 NextTaskTime);
  49 extern void     mDNSPlatformLock        (const mDNS *const m);
  50 extern void     mDNSPlatformUnlock      (const mDNS *const m);
  51
  52 extern void     mDNSPlatformStrCopy(const void *src,       void *dst);
  53 extern mDNSu32  mDNSPlatformStrLen (const void *src);
  54 extern void     mDNSPlatformMemCopy(const void *src,       void *dst, mDNSu32 len);
  55 extern mDNSBool mDNSPlatformMemSame(const void *src, const void *dst, mDNSu32 len);
  56 extern void     mDNSPlatformMemZero(                       void *dst, mDNSu32 len);
  57 extern mDNSs32  mDNSPlatformTimeNow();
  58 extern mDNSs32  mDNSPlatformOneSecond;
  59
  60 // The core mDNS code provides these functions, for the platform support code to call at appropriate times
  61 extern void     mDNSCoreInitComplete(mDNS *const m, mStatus result);
  62 extern void     mDNSCoreReceive(mDNS *const m, DNSMessage *const msg, const mDNSu8 *const end,
  63                                                                 mDNSIPAddr srcaddr, mDNSIPPort srcport, mDNSIPAddr dstaddr, mDNSIPPort dstport, mDNSIPAddr InterfaceAddr);
  64 extern void     mDNSCoreTask   (mDNS *const m);
  65 extern void     mDNSCoreSleep  (mDNS *const m, mDNSBool wake);
  66
  67 #ifdef  __cplusplus
  68         }
  69 #endif