stun.cxx

现在应用最广泛的一种私网穿透方式

      tv.tv_usec=150*1000; // 150 ms 
      if ( count == 0 ) tv.tv_usec=0;
		
      int  err = select(fdSetSize, &fdSet, NULL, NULL, &tv);
      int e = getErrno();
      if ( err == SOCKET_ERROR )
      {
         // error occured
         cerr << "Error " << e << " " << strerror(e) << " in select" << endl;
        return StunTypeFailure; 
     }
      else if ( err == 0 )
      {
         // timeout occured 
         count++;
			
         if ( !respTestI ) 
         {
            stunSendTest( myFd1, dest, username, password, 1 ,verbose );
         }         
			
         if ( (!respTestI2) && respTestI ) 
         {
            // check the address to send to if valid 
            if (  ( testI2dest.addr != 0 ) &&
                  ( testI2dest.port != 0 ) )
            {
               stunSendTest( myFd1, testI2dest, username, password, 10  ,verbose);
            }
         }
			
         if ( !respTestII )
         {
            stunSendTest( myFd2, dest, username, password, 2 ,verbose );
         }
			
         if ( !respTestIII )
         {
            stunSendTest( myFd2, dest, username, password, 3 ,verbose );
         }
			
         if ( respTestI && (!respTestHairpin) )
         {
            if (  ( testImappedAddr.addr != 0 ) &&
                  ( testImappedAddr.port != 0 ) )
            {
               stunSendTest( myFd1, testImappedAddr, username, password, 11 ,verbose );
            }
         }
      }
      else
      {
         //if (verbose) clog << "-----------------------------------------" << endl;
         assert( err>0 );
         // data is avialbe on some fd 
			
         for ( int i=0; i<2; i++)
         {
            Socket myFd;
            if ( i==0 ) 
            {
               myFd=myFd1;
            }
            else
            {
               myFd=myFd2;
            }
				
            if ( myFd!=INVALID_SOCKET ) 
            {					
               if ( FD_ISSET(myFd,&fdSet) )
               {
                  char msg[STUN_MAX_MESSAGE_SIZE];
                  int msgLen = sizeof(msg);
                  						
                  StunAddress4 from;
						
                  getMessage( myFd,
                              msg,
                              &msgLen,
                              &from.addr,
                              &from.port,verbose );
						
                  StunMessage resp;
                  memset(&resp, 0, sizeof(StunMessage));
						
                  stunParseMessage( msg,msgLen, resp,verbose );
						
                  if ( verbose )
                  {
                     clog << "Received message of type " << resp.msgHdr.msgType 
                          << "  id=" << (int)(resp.msgHdr.id.octet[0]) << endl;
                  }
						
                  switch( resp.msgHdr.id.octet[0] )
                  {
                     case 1:
                     {
                        if ( !respTestI )
                        {
									
                           testIchangedAddr.addr = resp.changedAddress.ipv4.addr;
                           testIchangedAddr.port = resp.changedAddress.ipv4.port;
                           testImappedAddr.addr = resp.mappedAddress.ipv4.addr;
                           testImappedAddr.port = resp.mappedAddress.ipv4.port;
									
                           if ( preservePort )
                           {
                              *preservePort = ( testImappedAddr.port == port );
                           }								
									
                           testI2dest.addr = resp.changedAddress.ipv4.addr;
									
                           if (sAddr)
                           {
                              sAddr->port = testImappedAddr.port;
                              sAddr->addr = testImappedAddr.addr;
                           }
									
                           count = 0;
                        }		
                        respTestI=true;
                     }
                     break;
                     case 2:
                     {  
                        respTestII=true;
                     }
                     break;
                     case 3:
                     {
                        respTestIII=true;
                     }
                     break;
                     case 10:
                     {
                        if ( !respTestI2 )
                        {
                           testI2mappedAddr.addr = resp.mappedAddress.ipv4.addr;
                           testI2mappedAddr.port = resp.mappedAddress.ipv4.port;
								
                           mappedIpSame = false;
                           if ( (testI2mappedAddr.addr  == testImappedAddr.addr ) &&
                                (testI2mappedAddr.port == testImappedAddr.port ))
                           { 
                              mappedIpSame = true;
                           }
								
							
                        }
                        respTestI2=true;
                     }
                     break;
                     case 11:
                     {
							
                        if ( hairpin ) 
                        {
                           *hairpin = true;
                        }
                        respTestHairpin = true;
                     }
                     break;
                  }
               }
            }
         }
      }
   }
	
   // see if we can bind to this address 
   //cerr << "try binding to " << testImappedAddr << endl;
   Socket s = openPort( 0/*use ephemeral*/, testImappedAddr.addr, false );
   if ( s != INVALID_SOCKET )
   {
      closesocket(s);
      isNat = false;
      //cerr << "binding worked" << endl;
   }
   else
   {
      isNat = true;
      //cerr << "binding failed" << endl;
   }
	
   if (verbose)
   {
      clog << "test I = " << respTestI << endl;
      clog << "test II = " << respTestII << endl;
      clog << "test III = " << respTestIII << endl;
      clog << "test I(2) = " << respTestI2 << endl;
      clog << "is nat  = " << isNat <<endl;
      clog << "mapped IP same = " << mappedIpSame << endl;
   }
	
   // implement logic flow chart from draft RFC
   if ( respTestI )
   {
      if ( isNat )
      {
         if (respTestII)
         {
            return StunTypeConeNat;
         }
         else
         {
            if ( mappedIpSame )
            {
               if ( respTestIII )
               {
                  return StunTypeRestrictedNat;
               }
               else
               {
                  return StunTypePortRestrictedNat;
               }
            }
            else
            {
               return StunTypeSymNat;
            }
         }
      }
      else
      {
         if (respTestII)
         {
            return StunTypeOpen;
         }
         else
         {
            return StunTypeSymFirewall;
         }
      }
   }
   else
   {
      return StunTypeBlocked;
   }
	
   return StunTypeUnknown;
}


int
stunOpenSocket( StunAddress4& dest, StunAddress4* mapAddr, 
                int port, StunAddress4* srcAddr, 
                bool verbose )
{
   assert( dest.addr != 0 );
   assert( dest.port != 0 );
   assert( mapAddr );
   
   if ( port == 0 )
   {
      port = randomPort();
   }
   unsigned int interfaceIp = 0;
   if ( srcAddr )
   {
      interfaceIp = srcAddr->addr;
   }
   
   Socket myFd = openPort(port,interfaceIp,verbose);
   if (myFd == INVALID_SOCKET)
   {
      return myFd;
   }
   
   char msg[STUN_MAX_MESSAGE_SIZE];
   int msgLen = sizeof(msg);
	
   StunAtrString username;
   StunAtrString password;
	
   username.sizeValue = 0;
   password.sizeValue = 0;
	
#ifdef USE_TLS
   stunGetUserNameAndPassword( dest, username, password );
#endif
	
   stunSendTest(myFd, dest, username, password, 1, 0/*false*/ );
	
   StunAddress4 from;
	
   getMessage( myFd, msg, &msgLen, &from.addr, &from.port,verbose );
	
   StunMessage resp;
   memset(&resp, 0, sizeof(StunMessage));
	
   bool ok = stunParseMessage( msg, msgLen, resp,verbose );
   if (!ok)
   {
      return -1;
   }
	
   StunAddress4 mappedAddr = resp.mappedAddress.ipv4;
   StunAddress4 changedAddr = resp.changedAddress.ipv4;
	
   //clog << "--- stunOpenSocket --- " << endl;
   //clog << "\treq  id=" << req.id << endl;
   //clog << "\tresp id=" << id << endl;
   //clog << "\tmappedAddr=" << mappedAddr << endl;
	
   *mapAddr = mappedAddr;
	
   return myFd;
}


bool
stunOpenSocketPair( StunAddress4& dest, StunAddress4* mapAddr, 
                    int* fd1, int* fd2, 
                    int port, StunAddress4* srcAddr, 
                    bool verbose )
{
   assert( dest.addr!= 0 );
   assert( dest.port != 0 );
   assert( mapAddr );
   
   const int NUM=3;
	
   if ( port == 0 )
   {
      port = randomPort();
   }
	
   *fd1=-1;
   *fd2=-1;
	
   char msg[STUN_MAX_MESSAGE_SIZE];
   int msgLen =sizeof(msg);
	
   StunAddress4 from;
   int fd[NUM];
   int i;
	
   unsigned int interfaceIp = 0;
   if ( srcAddr )
   {
      interfaceIp = srcAddr->addr;
   }

   for( i=0; i<NUM; i++)
   {
      fd[i] = openPort( (port == 0) ? 0 : (port + i), 
                        interfaceIp, verbose);
      if (fd[i] < 0) 
      {
         while (i > 0)
         {
            closesocket(fd[--i]);
         }
         return false;
      }
   }
	
   StunAtrString username;
   StunAtrString password;
	
   username.sizeValue = 0;
   password.sizeValue = 0;
	
#ifdef USE_TLS
   stunGetUserNameAndPassword( dest, username, password );
#endif
	
   for( i=0; i<NUM; i++)
   {
      stunSendTest(fd[i], dest, username, password, 1/*testNum*/, verbose );
   }
	
   StunAddress4 mappedAddr[NUM];
   for( i=0; i<NUM; i++)
   {
      msgLen = sizeof(msg)/sizeof(*msg);
      getMessage( fd[i],
                  msg,
                  &msgLen,
                  &from.addr,
                  &from.port ,verbose);
		
      StunMessage resp;
      memset(&resp, 0, sizeof(StunMessage));
		
      bool ok = stunParseMessage( msg, msgLen, resp, verbose );
      if (!ok) 
      {
         return false;
      }
		
      mappedAddr[i] = resp.mappedAddress.ipv4;
      StunAddress4 changedAddr = resp.changedAddress.ipv4;
   }
	
   if (verbose)
   {               
      clog << "--- stunOpenSocketPair --- " << endl;
      for( i=0; i<NUM; i++)
      {
         clog << "\t mappedAddr=" << mappedAddr[i] << endl;
      }
   }
	
   if ( mappedAddr[0].port %2 == 0 )
   {
      if (  mappedAddr[0].port+1 ==  mappedAddr[1].port )
      {
         *mapAddr = mappedAddr[0];
         *fd1 = fd[0];
         *fd2 = fd[1];
         closesocket( fd[2] );
         return true;
      }
   }
   else
   {
      if (( mappedAddr[1].port %2 == 0 )
          && (  mappedAddr[1].port+1 ==  mappedAddr[2].port ))
      {
         *mapAddr = mappedAddr[1];
         *fd1 = fd[1];
         *fd2 = fd[2];
         closesocket( fd[0] );
         return true;
      }
   }

   // something failed, close all and return error
   for( i=0; i<NUM; i++)
   {
      closesocket( fd[i] );
   }
	
   return false;
}

/* ====================================================================
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 * 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. The names "VOCAL", "Vovida Open Communication Application Library",
 *    and "Vovida Open Communication Application Library (VOCAL)" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written
 *    permission, please contact [e-mail].
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 * 4. Products derived from this software may not be called "VOCAL", nor
 *    may "VOCAL" appear in their name, without prior written
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 * Inc.  For