/tunnel.php

<?php



/* ##########################



	Devart HttpTunnel v1.69.    



	HTTP tunnel script.    



	This script allows you to manage database server even if the corresponding port is blocked or remote access to database server is not allowed.    



   ##########################



*/



$LOG = 1;       // Set to "0" to disable logging

$LOG_DEBUG = 1; // Set to "0" to disable additional debug logging

$LOGFILE = "httptunnel_server.log";

$LOGFILEHANDLE = 0;

$MAXLOGSIZE = "4000000";

$LIFETIME = 180; // script lifetime in seconds. If script was started and got no client within that time - it exits.

$READ_WRITE_ATTEMPTS = 100;

$CONN_FILE = "_connections.id.php";



function checkFunctionExists($functionName) {

  if (!function_exists($functionName)) {

      echo "Required function <b>$functionName</b> does not exist.</br>";

      return false;

  }



  return true;

}



// Creates connection temporary  file if not exists and checks permission to write

function CreateAndCheckConnFile($fileName) {



  if (file_exists($fileName)){

      $newFile = @fopen($fileName, 'a');

      if($newFile)

         fclose($newFile);

      else

         echo "<b>Error</b>: Failed to open ($fileName) file: Permission denied.";

          

  }

  else{

      $newFile = @fopen($fileName, 'w');

      if($newFile){

         fwrite($newFile, "<?php echo 'Devart HTTP tunnel temporary file.'; exit; ?>\r\n"); // forbid viewing this file through browser

         fclose($newFile);

      }

      else

         echo "<b>Error</b>: Failed to create ($fileName) file: Permission denied.";

      }

        

  if(!$newFile)

    exit;

}



if (!isset($_REQUEST["a"])) {  // query from browser



	echo "Devart HttpTunnel v1.69<br />";



    $functionList = array(

	    "set_time_limit",

        "stream_socket_server",

		"stream_socket_client",

		"stream_socket_get_name",

		"stream_set_blocking",

		"stream_socket_accept",

    );

    

    $exist = true;

    foreach($functionList as $functionName) {

	  $result = checkFunctionExists($functionName);

      $exist = $exist && $result;

    }



    if ($exist)

       CreateAndCheckConnFile($CONN_FILE);

    

    if ($exist)

      echo "Tunnel script is installed correctly. <br />You can establish connections through the HTTP tunnel.";

    else

      echo "Required PHP functions listed above are not available. Tunneling script will not work without these functions. Please read PHP manuals about how to install listed functions.";

    

    exit;

}



function myErrorHandler($errno, $errstr, $errfile, $errline) {

	switch ($errno) {

	case E_ERROR:

		$errfile=preg_replace('|^.*[\\\\/]|','',$errfile);

		echo $ERRSTR."Error in line $errline of file $errfile: [$errno] $errstr\n";

		exit;

	}

}	



function shutdown () {

	global $ipsock, $rmsock, $outcount, $incount, $td, $te, $sockname, $useunix;



	if (connection_status() & 1) { // ABORTED

		logline ($_SERVER["REMOTE_ADDR"].": Irregular tunnel disconnect -> disconnecting server");

		logline ($_SERVER["REMOTE_ADDR"].": Sent ".$outcount." bytes, received ".$incount." bytes");

	} elseif (connection_status() & 2) { // TIMEOUT

		logline ($_SERVER["REMOTE_ADDR"].": PHP script timeout -> disconnecting server");

		logline ($_SERVER["REMOTE_ADDR"].": Sent ".$outcount." bytes, received ".$incount." bytes");

	}

	

	if ($ipsock) fclose($ipsock);

	if ($rmsock) fclose($rmsock);

}



function logline ($msg) {

  log_line_to_file(0, $msg);

}



function logdebug($msg) {

  log_line_to_file(1, $msg);

}



function logerr($msg) {

  global $ERRSTR;

  

  logline($msg);

  echo $ERRSTR;

  echo $msg;

}



function log_line_to_file ($debug, $msg) {

	global $LOG, $LOG_DEBUG, $MAXLOGSIZE, $LOGFILE, $LOGFILEHANDLE;	

	if ($LOG && ((! $debug) || $LOG_DEBUG)) {

		$LOGFILEHANDLE=fopen ($LOGFILE, "a");

		if ($LOGFILEHANDLE) {			

			fwrite ($LOGFILEHANDLE, date("d.m.Y H:i:s")." - $msg\r\n");

			$lstat=fstat($LOGFILEHANDLE);

			if ($lstat["size"]>$MAXLOGSIZE) rotatelog();

			fclose($LOGFILEHANDLE);

		}

	}

}



function rotatelog() {

	global $LOG, $MAXLOGSIZE, $LOGFILE, $LOGFILEHANDLE;

	if ($LOG) {

     	fwrite ($LOGFILEHANDLE, date("d.m.Y H:i:s")." - Logfile reached maximum size ($MAXLOGSIZE)- rotating.\r\n");

		fclose ($LOGFILEHANDLE);

		rename ($LOGFILE,"$LOGFILE.old");

		$LOGFILEHANDLE=fopen ($LOGFILE, "a");

		if (!$LOGFILEHANDLE)

    		$LOG=0;

		else 

		    fwrite ($LOGFILEHANDLE, date("d.m.Y H:i:s")." - Opening new Logfile.\r\n");

	}

}



function create_client_socket() {

  global $_REQUEST;

  

    if (!isset($_REQUEST["port"])) {

	  echo $ERRSTR."Port not set.";

	  return 0;

	}

	

	$port = $_REQUEST["port"];

    $client = stream_socket_client("tcp://127.0.0.1:".$port);

	if ($client) {

	  stream_set_blocking($client, 1);

	}

	return $client;

}



function send_server_script_message($command) {

    global $_REQUEST;

	

	$client = create_client_socket();

	if (!$client) {

	  logerr("Failed to create client socket");

	  return FALSE;

	}

	if (fwrite($client, $command, 1) === FALSE) {

	  logerr("Failed to send message to server script.");

	  fclose($client);

	  return FALSE;

	}

	fclose($client);

	return TRUE;

}



function increase_script_lifetime() {

  global $LIFETIME;

  

  set_time_limit($LIFETIME);

  logdebug("Script liftetime incremented with $LIFETIME");

}



function write_to_socket($socket, $buffer, $count) {

  global $READ_WRITE_ATTEMPTS;

  

  $totalCount = 0;

  $retryCount = 0;

  

  do {

    if ($retryCount > 0) {

	    usleep(10000); // 10ms

    }

    

    if (!$socket)

      break;

    

	  $written = fwrite($socket, $buffer, $count);

    $buffer = substr($buffer, $written);

	  $totalCount += $written;

    

    if ($retryCount > 0) {

      logdebug("Attempt to write #".($retryCount + 1)." Write: ".$written);

    }

    

    $retryCount = $retryCount + 1;

  } while($totalCount < $count && $retryCount < $READ_WRITE_ATTEMPTS);

  

  if ($totalCount != $count)

    logline("ERROR: Failed to write to socket $count bytes, $totalCount actually written.");

	

  return $totalCount;

}



// reads specified byte count from socket

function read_from_socket($socket, &$buffer, $count) {

  global $READ_WRITE_ATTEMPTS;

  

  $totalCount = 0;

  $retryCount = 0;

  

  $buffer = "";

  $readBuffer;

  

  do {

    if ($retryCount > 0) {

	    usleep(10000); // 10ms

    }

    

    if (!$socket)

      break;

    

    $readBuffer = fread($socket, $count);

    $read = strlen($readBuffer);

    $buffer = $buffer.$readBuffer;

    

    if ($retryCount > 0) {

      logdebug("Attempt to read #".($retryCount + 1)." Read: ".$read);

    }

    

    $totalCount += $read;

    $retryCount = $retryCount + 1;

    

  } while($totalCount < $count && $retryCount < $READ_WRITE_ATTEMPTS);

  

  if ($totalCount != $count)

    logerr("Failed to read from socket $count bytes, $totalCount actually read.");

	

  return $totalCount;

}



// packet:  size of data count |                      data count | data

// lengths:             1 byte | up to 255 bytes, typically 1 - 5| up to $MaxCount

function write_data_packet($socket, &$buffer, $count) {

    

	$countLength = strlen($count);

	// write length of data count digit

	write_to_socket($socket, $countLength, 1);

	// write data count

	write_to_socket($socket, $count, $countLength);

	// write data

	$writeCount = write_to_socket($socket, $buffer, $count);

	if ($writeCount == $count)

	  return $writeCount;

	else

	  return 0;

}



function read_data_packet($socket, &$buffer) {

    

	// obtain data length digit length

	read_from_socket($socket, $countSize, 1);

	// read data length

	read_from_socket($socket, $readCount, $countSize);

	$expectedReadCount = $readCount;

	// read data

    $readCount = read_from_socket($socket, $buffer, $readCount);

	if ($readCount == $expectedReadCount)

	  return $readCount;

	else

	  return FALSE;

}



// Start of the tunnel script

$isServer = FALSE;



if (version_compare("5.0.0",phpversion())==1) die ("Only PHP 5 or above supported");

error_reporting(0);

set_error_handler("myErrorHandler");

register_shutdown_function ("shutdown");

// no-cache

Header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");

Header("Cache-Control: no-cache, must-revalidate");

Header("Pragma: no-cache"); // HTTP/1.1 

Header("Last-Modified: ".gmdate("D, d M Y H:i:s")."GMT");



header("Content-Type: application/octet-stream");



ob_implicit_flush();



// Maximum bytes to read at once

$MaxReadCount = 16*1024;



// operation success identification

$OKSTR = "OK:";

$ERRSTR = "ER:";



$CONN_FILE_MAXSIZE = 100;



// Primary tunnel connection

// need the following REQUEST vars:

// a: "c"

// s: remote server name

// p: remote server port



// every operation output at least first three chars identifying the success of operation: "OK:" if succeeded, "ER:" if not.

//



if ($_REQUEST["a"]=="c") {  // run server script

    $isServer=TRUE;

    // clear log

	if ($LOG_DEBUG) {

	  // truncate log file

	  $logfile = fopen($LOGFILE, 'w');

	  fclose($logfile);

	}



    $dad=$_REQUEST["s"];

	$dpo=$_REQUEST["p"];



	// open the interprocess socket

	$errno = 0;

	$errstr = "";

	$ipsock = stream_socket_server("tcp://127.0.0.1:0", $errno, $errstr);

		

	if (!$ipsock) {

		logerr("stream_socket_server() failed: reason:".$errno." ".$errstr);

		exit;

	}

	

	$port=stream_socket_get_name($ipsock,false);

	$port=preg_replace('/^.*?:/','', $port);

	

	stream_set_blocking($ipsock, 1);

	

    // open the remote socket

	$rmsock = stream_socket_client("tcp://".$dad.":".$dpo, $errno, $errstr);

	

	if (!$rmsock) {

	  logerr("Failed to create remote socket at $dad: $dpo. ".$errno." ".$errstr);

	  exit;

	}

	else {

    if (isset($_REQUEST["nonblock"]))

      $block = 0;

    else

      $block = 1;

    stream_set_blocking($rmsock, $block);

	  logline("Connected to remote  $dad: $dpo");

	}

	

	// write connection identificator to file. Echo'ing is not appropriate in case of antiviral software, it would be blocked until script finishes

	$newConnFile = FALSE;

	$connFileMode = "a";

	if (file_exists($CONN_FILE)) {

	  $connFile = fopen($CONN_FILE, "r");

	  $lstat=fstat($connFile);

	  fclose($connFile);

	  if ($lstat["size"]>$CONN_FILE_MAXSIZE) {

	    $connFileMode = "w";

		$newConnFile = TRUE;

	  }

	}

	else {

	  $newConnFile = TRUE;

	}

	

	$connFile = fopen($CONN_FILE, $connFileMode);

	if ($connFile) {

	    if ($newConnFile) {

	      fwrite($connFile, "<?php echo 'Devart HTTP tunnel temporary file.'; exit; ?>\r\n"); // forbid viewing this file through browser

	    }

        $connectionId = str_replace("_", " ", $_REQUEST["id"]);	

		fwrite ($connFile, $connectionId." ".$port."\r\n");

		fclose($connFile);

	}

	else {

	  logerr("Failed to create connection temporary file.");

	  exit;

	}

	

	set_time_limit($LIFETIME);



	$exit = false;

	$buffer = array();

	$countBuffer = array();

	

	while (!$exit) {

	  logdebug("Waiting for client...");

	  $client = stream_socket_accept($ipsock);

		logline("Client accepted");

		if ($client === FALSE) {

		  logline("ERROR: Bad client.");

		  continue;

		}

	    // read command

		$count = read_from_socket($client, $buffer, 1);

		if ($count == 0) {

		  logline("Error reading client command.");

		  $exit = true;

		}

		

		logdebug("Read from client ($count): ".$buffer[0]);

				

		$command = $buffer[0];

		

		increase_script_lifetime();

		

		if ($command == "x") {  // close

		    logline("Shutting down on client request.");

		    $exit = true;  // shutdown

		}

		else if ($command == "r") { // read

		

		    if (!$rmsock) {

			  logline("ERROR: rmsock is off");

			  $exit = true;

			  break;

			}

			

			$readCount = 0;

			

      $buffer = fread($rmsock, $MaxReadCount);

      if ($buffer === FALSE) {

        logline("ERROR: Remote server disconnected.");

        $exit = true;

        break;

      }

      else {

        $readCount = strlen($buffer);

          logline("Read from remote:($readCount)");

      }

			  

		  if ($readCount >= 0) {

        if ($readCount == 0)

          logline("Nothing to read from remote.");

        

			  $writeCount = write_data_packet($client, $buffer, $readCount);

			  logdebug("Write to client($writeCount): $buffer");

			  if ($readCount > 0 && $writeCount == 0) {

          logerr("Failed to write to client.");

			    $exit = true;

			  }

			}

		}

		else if ($command == "w") { // write

			

		    if (!$rmsock) {

			  logline("ERROR: rmsock is off");

			  $exit = true;

			  break;

			}

			$readCount = read_data_packet($client, $buffer);

		    logline("Write from client: $readCount");

		    if ($readCount > 0) {

			    $writeCount = write_to_socket($rmsock, $buffer, $readCount);

			    logdebug("Write to remote($writeCount): $buffer");

			}

		}

		else if ($command == "l") {   // increment lease time

		  logline("Lease time increased.");

		}

		else if ($command == "t") {  // test connection command

		    $writeCount = write_to_socket($client, $OKSTR, strlen($OKSTR));

			if ($writeCount == 0)

			  $exit = true;

		}

        else {

		  logline("ERROR: Unknown command: $command. Exiting.");

		  $exit = true;

		}

	}

	

	logline("Server script closed.");

	exit;

}



if ($_REQUEST["a"]=="r") {  // read

	

  	$client = create_client_socket();

	if (!$client) {

	  logerr("Failed to connect to server script.");

	  exit;

	}

	

	logdebug("Client: Reading from server script");

		

	if (write_to_socket($client, "r", 1) == 0) { // write "Read" command

	  logerr("Write to server script failed.");

	  fclose($client);

	  exit;

	}

	

	$buffer;

	$readCount = read_data_packet($client, $buffer);

	if ($readCount === FALSE) {

	  logerr("Failed to read response from server script.");

	  fclose($client);

	  exit;

	}

	

	$totalCount = strlen($OKSTR) + $readCount;

	

	$outputStr = $OKSTR.$buffer;

	

	header("Content-Length: ".$totalCount);

	

  logline("Client: Read from server $readCount");

	echo $outputStr;

	

	fclose($client);

	exit;

}



if ($_REQUEST["a"]=="w") {  // write

    $client = create_client_socket();

	if (!$client) {

	  logerr("Failed to connect to server script.");

	  exit;

	}

	  

  $postBody= isset($_POST['base64body'])?base64_decode($_POST['base64body']):file_get_contents("php://input");  // Retrieve RAW POST data	

	$writeData = $postBody;

	$expectedWriteCount = strlen($writeData);

	$writeCount = write_to_socket($client, "w", 1);  // indicate that this is the "Write" command

	if ($writeCount > 0)

	  $writeCount = write_data_packet($client, $writeData, $expectedWriteCount);

	

	if ($writeCount == 0) {

	  logerr("Write to server script failed.");

	  fclose($client);

	  exit;

	}

	  

	logdebug("Client: Written $writeCount");

	

	fclose($client);

	echo $OKSTR;

	exit;

}



if ($_REQUEST["a"]=="x") {  // close

	

	echo $OKSTR."Shutted down.";

	send_server_script_message("x");

	exit;

}



if ($_REQUEST["a"] == "l") { // increment server script lease time

  

  if (send_server_script_message("l"))

    echo $OKSTR."Incremented server script lease time.";

  exit;

}



if ($_REQUEST["a"] == "t") { // test newly created connection

    

	$connectionId = str_replace("_", " ", $_REQUEST["id"]);

	logline($connectionId);

	$connections = file_get_contents($CONN_FILE);

  

    if ($connections === FALSE) {

	   logerr("Failed to open $CONN_FILE.");

	   exit;

	}

	

	$lines = explode("\r\n", $connections);

	

	// skip first line

	for($i = 1; $i < count($lines); ++$i) {

	  $line = $lines[$i];

	  $pos = strpos($line, $connectionId);

	  if ($pos === FALSE)

	    continue;

		

	  if ($pos === 0) {  // starts with

	    $parts = explode(" ", $line);

		if (count($parts) != 3) {

		  echo "Invalid connection record";

		  exit;

		}

		

		echo $OKSTR.$parts[2]."\n"."$LIFETIME\n";

		exit;

	  }

	}

	

	logerr("Connection entry not found.");

	exit;

}



logerr("Invalid tunneling script parameter: ".$_REQUEST["a"]);



?>