// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
//  File: UpdateIP.cpp
//  Created 10/04/2002
// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
//  Purpose:  
//    This program is meant to demonstrate the protocol
//  used in connecting to a dynamic dns server and 
//  performing a dynamic IP update.
// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

#include "stdafx.h"
#include "winsock.h"

// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
//  You will need to modify these values to the host, zone 
//  and password for the domain you wish to update.
// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
#define DOMAIN_HOST			"www"
#define DOMAIN_ZONE			"mydomain.com"
#define DOMAIN_PASSWORD			"password"

// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
//  Our update server information
// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
#define UPDATE_SERVER		"dynamic.name-services.com."
#define HTTP_PORT			80

#define RESPONSE_BUFFER		2048




// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
//  Function: senda()
//  Date: 10/04/2002
// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
//  Parameters:
//    SOCKET nSock - The valid socket which we
//      are to use to send the string.
//    const char *cText - A null terminated text 
//      string to be sent to socket.
// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
//  Purpose:
//    This function just wraps the standard send 
//  using strlen to calculate the length, and 
//  assumes no options.
// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
int senda( SOCKET nSock, const char *cText ) {
	return send( nSock, cText, (int)strlen(cText), 0 );
}
// =-=-=-=-=-=-=-=-=-=-=-=
//  End Function senda()
// =-=-=-=-=-=-=-=-=-=-=-=




// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
//  Function: TerminateConnection()
//  Date: 10/04/2002
// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
//  Parameters:
//    SOCKET nSock - The socket that we are to
//      make sure is closed.
// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
//  Purpose:
//    This function is responsible for gracefully 
//  closing a given socket if a connection is 
//  established.
// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
void TerminateConnection( SOCKET nSock ) {
	
	// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
	//  If we have a socket that looks valid, we want to gracefully close it.
	// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
	if( INVALID_SOCKET != nSock ) {

		// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
		//  Make sure that we have signaled shutdown from our end of the socket.
		// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
		shutdown( nSock, 1 );

		// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
		//  Here we read all remaining data that the server has to send.
		// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
		char cFlush[1024];
		while( 0 < recv( nSock, cFlush, 1024, 0 ) );

		// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
		//  Now we are free to close the socket.
		// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
		if( 0 != closesocket( nSock ) )
			printf( "Error - closesocket() failed: %d", WSAGetLastError() );
	}
}
// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
//  End Function TerminateConnection()
// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=




// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
//  Function: main()
//  Date: 10/04/2002
// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
//  Purpose:
//    This function performs a dynamic dns update
// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
//  NOTE:
//     On error we always jump to the  cleanup 
//  routines at the end of the function.
// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
int main(int argc, char **argv ) {
	SOCKET nSock = INVALID_SOCKET;

	// =-=-=-=-=-=-=-=-=-=-=-=
	//  Initialize winsock.
	// =-=-=-=-=-=-=-=-=-=-=-=
	WSADATA wsaData;
	if( 0 != WSAStartup( MAKEWORD( 1, 1 ), &wsaData ) ) {
		printf( "Error - Failed to initialize winsock: %d\r\n", WSAGetLastError() );
		goto End;
	}

	// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
	//  Create the TCP socket that will be 
	//  used to connect to the interface.
	// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
	nSock = socket( AF_INET, SOCK_STREAM, IPPROTO_TCP );
	if( INVALID_SOCKET == nSock ) {
		printf( "Error - Failed to create socket: %d.\r\n", WSAGetLastError() );
		goto End;
	}

	// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
	//  Look up the current IP for the update server.
	// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
	struct hostent *pHostEnt = NULL;
	if( NULL == ( pHostEnt = gethostbyname( UPDATE_SERVER ) ) ) {
		printf( "Error - Failed to look up server %s: %d\r\n", UPDATE_SERVER, WSAGetLastError() );
		goto End;
	}

	// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
	//  Fill in the remote machines address information.
	// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
	struct sockaddr_in SockAddr;
	memset( &SockAddr, 0x00, sizeof( struct sockaddr_in ) );	// Zero out the structure first
	SockAddr.sin_family = AF_INET;
	SockAddr.sin_port = htons( HTTP_PORT );						// Set the port
	memcpy( &SockAddr.sin_addr.S_un.S_addr, pHostEnt->h_addr_list[0], sizeof( unsigned long ) );  // Fill in the IP address that we looked up.

	// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
	//  Attempt to make the TCP connection.
	// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
	if( SOCKET_ERROR == connect( nSock, (struct sockaddr *)&SockAddr, sizeof( struct sockaddr_in  ) ) ) {
		printf( "Error - Failed to connect to remote server: %d\r\n", WSAGetLastError() );
		goto End;
	}

	// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
	//  Note: All information is sent on the query string.
	// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
	{
		// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
		//  Start out our HTTP session by requesting a page.
		// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
		senda( nSock, "GET /interface.asp" );

		// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
		//  Next we specify that we want to update a dns host.
		// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
		senda( nSock, "?Command=SetDNSHost" );

		// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
		//  Next specify the domain & host that we want to update.
		// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
		senda( nSock, "&HostName=" );	senda( nSock, DOMAIN_HOST );
		senda( nSock, "&Zone=" );		senda( nSock, DOMAIN_ZONE );

		// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
		//  Optional:
		//    The update takes an optional address parameter.  If 
		//  supplied, the server updates dns to the given IP.  When 
		//  omitted, the client's IP is used.
		// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
		//  senda( nSock, "&Address=" );
		//  senda( nSock, "1.2.3.4" );

		// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
		//  Now we add the domain's update password.
		// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
		senda( nSock, "&DomainPassword=" ); senda( nSock, DOMAIN_PASSWORD );

		// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
		//  Finally we finish off the HTTP request.
		// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
		senda( nSock, " HTTP/1.0\r\n\r\n" );
	}

	// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
	//  Let the server know that we are done sending
	//  by closing our end of the socket.
	// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
	shutdown( nSock, 1 );
	
	// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
	//  Here we just read print out the server's response 
	//  until an error occurs or the server is done and 
	//  closes the socket.
	// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
	{
		char cResponse[RESPONSE_BUFFER];
		int nReadResult = SOCKET_ERROR;
		BOOL lDone = FALSE;
		
		// =-=-=-=-=-=-=-=-=-=-=-=
		//  Loop until signaled.
		// =-=-=-=-=-=-=-=-=-=-=-=
		while( !lDone ) {
			
			// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
			//  Attempt to read from the socket
			// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
			nReadResult = recv( nSock, cResponse, RESPONSE_BUFFER, 0 );

			// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
			//  Handle the results of our read.
			// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
			switch( nReadResult ) {
			case SOCKET_ERROR: 

				// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
				//  An unexpected error occurred.
				// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
				printf( "Error: Error reading from socket: %d.\r\n", WSAGetLastError() );
			case 0: 
				
				// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
				//  The server closed the connection.
				// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
				lDone = TRUE;
				break;
			default: 

				// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
				//  All appearantly went well with our socket read.
				// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
				//  NULL terminate the string we read & print it.
				// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
				cResponse[nReadResult] = 0x00;	
				printf( cResponse );
			}
		}
	}
End:
	// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
	//  Make sure that our socket has been properly closed.
	// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
	TerminateConnection( nSock );

	return 0;
}
// =-=-=-=-=-=-=-=-=-=-=-=
//  End Function: main()
// =-=-=-=-=-=-=-=-=-=-=-=