ExternalDns.hxx

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#if !defined(RESIP_EXTERNAL_DNS_HXX)
#define RESIP_EXTERNAL_DNS_HXX
 
#include <vector>
 
#include "rutil/AsyncID.hxx"
#include "rutil/GenericIPAddress.hxx"
 
struct hostent;
 
namespace resip
{
class ExternalDnsHandler;
class ExternalDnsRawResult;
class ExternalDnsHostResult;
class FdPollGrp;
 
//used by the asynchronous executive
class ExternalDns
{
   public:
      enum Features
      {
         None = 0,
         TryServersOfNextNetworkUponRcode3 = 1 << 0,   // 'No such name'
         ReturnAllResults = 1 << 1 //Don't discard errors, the precise error values are used to
                                   //decide whether the hosts file should be consulted, see
                                   //DnsStub.cxx DnsStub::Query::process()
      };
 
      //returns Success, BuildMismatch, otherwise ExternalDns specific 
      //error message can be pulled from errorMessage
      enum InitResult
      {
         Success = 0,
         BuildMismatch = 4777
      };
 
      // When enabled, a resolver that can tell when its sockets are connected
      // (c-ares) calls the socket function a second time, once connected, as
      // SIP TCP connections do.  Set through
      // Connection::setEnablePostConnectSocketFuncCall().
      static void setEnablePostConnectSocketFuncCall(bool enabled = true);
      static bool getEnablePostConnectSocketFuncCall();
 
 
      //
      virtual int init(const std::vector<GenericIPAddress>& additionalNameservers,
                       AfterSocketCreationFuncPtr,
                       int dnsTimeout = 0,
                       int dnsTries = 0,
                       unsigned int features = 0) = 0; // bit mask of Features
 
      // reinitializes with the same additionalNameservers and AfterSocketCreationFuncPtr as last call to init
      virtual int init(int dnsTimeout = 0, int dnsTries = 0, unsigned int features = 0) = 0;  
 
      virtual void changeNameServers(const std::vector<GenericIPAddress>& additional) = 0;
      //returns 'true' only is there are changes in the DNS server list
      virtual bool checkDnsChange() = 0;
 
      //For use in select timeout
      virtual unsigned int getTimeTillNextProcessMS() = 0;
 
      //this is scary on windows; the standard way to get a bigger fd_set is to
      //redefine FD_SETSIZE befor each inclusion of winsock2.h, so make sure
      //external libraries have been properly configured      
      // MUST not be called when pollGrp (below) is active
      // Only needed when no FdPollGrp is set (e.g. resip/stack/test/testDns)
      virtual void buildFdSet(fd_set& read, fd_set& write, int& size) = 0;
      virtual void process(fd_set& read, fd_set& write) = 0;
 
      virtual void setPollGrp(FdPollGrp *grp) = 0;
 
      // called by DnsStub to process timers requested by getTimeTillNext...()
      // only used when poll group is active
      virtual void processTimers() = 0;
 
      virtual void freeResult(ExternalDnsRawResult res) = 0;
      virtual void freeResult(ExternalDnsHostResult res) = 0;
 
      //caller must clean up memory
      virtual char* errorMessage(long errorCode) = 0;
      
      virtual ~ExternalDns()  {}
 
      virtual void lookup(const char* target, unsigned short type, ExternalDnsHandler* handler, void* userData) = 0;
 
      virtual bool hostFileLookup(const char* target, in_addr &addr) = 0;
      virtual bool hostFileLookupLookupOnlyMode() = 0;
};
 
class ExternalDnsResult : public AsyncResult
{
   public:
      ExternalDnsResult(long errorCode, void* uData) : AsyncResult(errorCode) , userData(uData) {}
      ExternalDnsResult(void* uData) : userData(uData) {}
      void* userData;
};
 
//should this be nested?
class ExternalDnsRawResult : public ExternalDnsResult
{
   public:
      ExternalDnsRawResult(unsigned char* buf, int len, void* uData) : 
         ExternalDnsResult(uData),
 
         abuf(buf),
         alen(len) 
      {}
      ExternalDnsRawResult(long errorCode, unsigned char* buf, int len, void* uData) : 
         ExternalDnsResult(errorCode, uData),
         abuf(buf),
         alen(len)
         {}
         
      unsigned char* abuf;
      int alen;
};
 
class ExternalDnsHostResult : public ExternalDnsResult
{
   public:
      ExternalDnsHostResult(hostent* h, void* uData) :
         ExternalDnsResult(uData), 
         host(h)
      {}
      ExternalDnsHostResult(long errorCode, void* uData) : ExternalDnsResult(errorCode, uData) {}
         
      hostent* host;
};
 
class ExternalDnsHandler
{
   public:
      //underscores are against convention, but pretty impossible to read
      //otherwise. ?dcm? -- results stack or heap? 
      //the free routines can be dealt w/ iheritence instead if pointers are used
      //virtual void handle_NAPTR(ExternalDnsRawResult res) = 0;
      //virtual void handle_SRV(ExternalDnsRawResult res) = 0;
      //virtual void handle_AAAA(ExternalDnsRawResult res) = 0;
      //virtual void handle_host(ExternalDnsHostResult res) = 0;
 
      // new version
      virtual ~ExternalDnsHandler() {}
      virtual void handleDnsRaw(ExternalDnsRawResult res) = 0;
};
 
}
 
#endif
      
 
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