controlsocket.java

COPE the first practical network coding scheme which is developped on click

     * @exception IOException If there was a stream or socket error.
     * @exception ClickException If there was some other error
     * accessing the handler (e.g., the ControlSocket returned an unknown
     * unknown error code, or the response could otherwise not be understood).
     * @see #read
     * @see #write
     * @see #getConfigElementNames
     * @see #getElementHandlers */

    public boolean checkHandler(String elementName, String handlerName,
				boolean writeHandler)
	throws ClickException, IOException {
	String handler = handlerName;
	if (elementName != null)
	    handler = elementName + "." + handlerName;
	_out.write((writeHandler ? "CHECKWRITE " : "CHECKREAD ")
		   + handler + "\n");
	_out.flush();
	
	// make sure we read all the response lines... 
	String response = "";
	String lastLine = null;
	do {
	    lastLine = _in.readLine();
	    if (lastLine == null)
		throw new IOException("ControlSocket stream closed unexpectedly");
	    if (lastLine.length() < 4)
		throw new ClickException("Bad response line from ControlSocket");
	    response = response + lastLine.substring(4);
	} while (lastLine.charAt(3) == '-');
	
	int code = getResponseCode(lastLine);
	switch (getResponseCode(lastLine)) {
	  case CODE_OK:
	  case CODE_OK_WARN:
	    return true;
	  case CODE_NO_ELEMENT:
	  case CODE_NO_HANDLER:
	  case CODE_HANDLER_ERR:
	  case CODE_PERMISSION:
	    return false;
	  case CODE_UNIMPLEMENTED:
	    if (elementName == null)
		handleErrCode(code, elementName, handlerName, response);
	    return checkHandlerWorkaround(elementName, handlerName, writeHandler);
	  default:
	    handleErrCode(code, elementName, handlerName, response);
	    return false;
	}
    }
    
    private boolean checkHandlerWorkaround(String elementName, String handlerName, boolean writeHandler)
	throws ClickException, IOException {
	// If talking to an old ControlSocket, try the "handlers" handler
	// instead.
	String s = readString(elementName, "handlers");
	int pos = 0;

	// Find handler with same name.
	while (true) {
	    pos = s.indexOf(handlerName, pos);
	    if (pos < 0)	// no such handler
		return false;
	    if ((pos == 0 || s.charAt(pos - 1) == '\n')
		&& Character.isWhitespace(s.charAt(pos + handlerName.length())))
		break;
	    pos++;
	}

	// we have a matching handler: will it be read/write suitable?
	char wantType = (writeHandler ? 'w' : 'r');
	for (pos += handlerName.length(); pos < s.length() && Character.isWhitespace(s.charAt(pos)); pos++)
	    /* nada */;
	for (; pos < s.length(); pos++) {
	    char c = s.charAt(pos);
	    if (Character.toLowerCase(c) == wantType)
		return true;
	    else if (Character.isWhitespace(c))
		break;
	}
	return false;
    }
    
    /**
     * Returns the result of reading an element's handler.
     *
     * @param elementName The element name.
     * @param handlerName The handler name.
     * @return Char array containing the data.
     * @exception NoSuchHandlerException If there is no such read handler.
     * @exception NoSuchElementException If there is no such element in the current configuration.
     * @exception HandlerErrorException If the handler returned an error.
     * @exception PermissionDeniedException If the router would not let us access the handler.
     * @exception IOException If there was a stream or socket error.
     * @exception ClickException If there was some other error
     * accessing the handler (e.g., the ControlSocket returned an unknown
     * unknown error code, or the response could otherwise not be understood).
     * @see #checkHandler
     * @see #write
     * @see #getConfigElementNames
     * @see #getElementHandlers
     */
    public char[] read(String elementName, String handlerName) 
	throws ClickException, IOException {
	String handler = handlerName;
	if (elementName != null)
	    handler = elementName + "." + handlerName;
	_out.write("READ " + handler + "\n");
	_out.flush();
	
	// make sure we read all the response lines... 
	String response = "";
	String lastLine = null;
	do {
	    lastLine = _in.readLine();
	    if (lastLine == null)
		throw new IOException("ControlSocket stream closed unexpectedly");
	    if (lastLine.length() < 4)
		throw new ClickException("Bad response line from ControlSocket");
	    response = response + lastLine.substring(4);
	} while (lastLine.charAt(3) == '-');
	
	int code = getResponseCode(lastLine);
	if (code != CODE_OK && code != CODE_OK_WARN) 
	    handleErrCode(code, elementName, handlerName, response);
	
	response = _in.readLine();
	if (response == null)
	    throw new IOException("ControlSocket stream closed unexpectedly");
	int num_bytes = getDataLength(response);
	if (num_bytes < 0)
	    throw new ClickException("Bad length returned from ControlSocket");

	if (num_bytes == 0) 
	    return new char[0];
	
	// sometimes, read will return without completely filling the
	// buffer (e.g. on win32 JDK)
	char data[] = new char[num_bytes];
	int bytes_left = num_bytes;
	while (bytes_left > 0) {
	    int bytes_read = _in.read(data, num_bytes - bytes_left, bytes_left);
	    bytes_left -= bytes_read;
	}
	return data;
    }
    
    public String readString(String el, String handler) 
	throws ClickException, IOException {
	return new String(read(el, handler));
    }
    
    public String readString(HandlerInfo hinfo) 
	throws ClickException, IOException {
	return new String(read(hinfo.elementName, hinfo.handlerName));
    }


    private void handleWriteResponse(String elementName, String handlerName)
	throws ClickException, IOException {
	String response = "";
	String lastLine = null;
	do {
	    lastLine = _in.readLine();
	    if (lastLine == null)
		throw new IOException("ControlSocket stream closed unexpectedly");
	    if (lastLine.length() < 4)
		throw new ClickException("Bad response line from ControlSocket");
	    response = response + lastLine.substring(4) + "\n";
	} while (lastLine.charAt(3) == '-');
	
	int code = getResponseCode(lastLine);
	if (code != CODE_OK && code != CODE_OK_WARN) 
	    handleErrCode(code, elementName, handlerName, response);
    }
        
    /**
     * Writes data to an element's handler.
     *
     * @param elementName The element name.
     * @param handlerName The handler name.
     * @param data Char array containing the data.
     * @exception NoSuchHandlerException If there is no such write handler.
     * @exception NoSuchElementException If there is no such element in the current configuration.
     * @exception HandlerErrorException If the handler returned an error.
     * @exception PermissionDeniedException If the router would not let us access the handler.
     * @exception IOException If there was a stream or socket error.
     * @exception ClickException If there was some other error
     * accessing the handler (e.g., the ControlSocket returned an unknown
     * unknown error code, or the response could otherwise not be understood).
     * @see #checkHandler
     * @see #write
     * @see #getConfigElementNames
     * @see #getElementHandlers
     */
    public void write(String elementName, String handlerName, char[] data) 
	throws ClickException, IOException {

	String handler = handlerName;
	if (elementName != null)
	    handler = elementName + "." + handlerName;
	
	_out.write("WRITEDATA " + handler + " " + data.length + "\n");
	_out.write(data, 0, data.length);
	_out.flush();
	
	handleWriteResponse(elementName, handlerName);
    }

    public void write(String elementName, String handlerName, String data) 
	throws ClickException, IOException {

	String handler = handlerName;
	if (elementName != null)
	    handler = elementName + "." + handlerName;
	
	_out.write("WRITEDATA " + handler + " " + data.length() + "\n");
	_out.write(data);
	_out.flush();
	
	handleWriteResponse(elementName, handlerName);
    }

    public void write(HandlerInfo info, char[] data) 
	throws ClickException, IOException {
	write(info.elementName, info.handlerName, data);
    }

    public void write(HandlerInfo info, String data) 
	throws ClickException, IOException {
	write(info.elementName, info.handlerName, data);
    }

    /**
     * Close the ControlSocket.
     */
    public void close() {
	try {
	    _sock.close(); 
	} catch (IOException ex) {
	}
    }

    private int getResponseCode(String s) {
	String code_str = s.substring(0, 3);
	try { 
	    return Integer.parseInt(code_str); 
	} catch (NumberFormatException ex) { 
	    return -1; 
	}
    }

    private int getDataLength(String s) {
	int i;
	for (i = 0; i < s.length() && !Character.isDigit(s.charAt(i)); i++)
	    ; // do it
	if (i == s.length()) 
	    return -1;
	String len_str = s.substring(i);
	try { 
	    return Integer.parseInt(len_str); 
	} catch (NumberFormatException ex) { 
	    return -1; 
	}
    }

    private void handleErrCode(int code, String elementName, 
			       String handlerName, String response) 
	throws ClickException {

	String hid = handlerName;
	if (elementName != null)
	    hid = elementName + "." + handlerName;

	switch (code) {
	 case CODE_SYNTAX_ERR: 
	  throw new ClickException("Syntax error calling handler `" + hid + "'");
	 case CODE_UNIMPLEMENTED: 
	  throw new ClickException("Unimplemented ControlSocket command");
	 case CODE_NO_ELEMENT:
	  throw new ClickException.NoSuchElementException(elementName);
	 case CODE_NO_HANDLER: 
	  throw new ClickException.NoSuchHandlerException(hid); 
	 case CODE_HANDLER_ERR: 
	  throw new ClickException.HandlerErrorException(hid, response);
	 case CODE_PERMISSION: 
	  throw new ClickException.PermissionDeniedException(hid); 
	 default:
	  throw new ClickException("Unknown ControlSocket error code " + code);
	}
    }


    /*
     * test driver 
     */
    public static void main(String args[]) {
	if (args.length == 0 || args.length > 3) {
	    System.out.println("to list router info, `java ControlSocket'");
	    System.out.println("to list handlers, `java ControlSocket <element>'");
	    System.out.println("to read, `java ControlSocket <element> <handler>'");
	    System.out.println("to write, `java ControlSocket <element> <handler> <data>'");
	    System.out.println("router info follows");
	}

	InetAddress localhost = null;
	try { 
	    // localhost = InetAddress.getLocalHost(); 
	    localhost = InetAddress.getByName("bermuda.lcs.mit.edu");
	} catch (UnknownHostException ex) { 
	    System.out.println("Can't get localhost address");
	    System.exit(-1);
	}
    
	try {
	    ControlSocket cs = new ControlSocket(localhost, 7777);
	    if (args.length == 2) {
		char data[] = cs.read(args[0], args[1]);
		System.out.println(data);
	    } else if (args.length == 3) {
		cs.write(args[0], args[1], args[2].toCharArray());
	    } else if (args.length == 1) {
		// dump element handler info
		Vector v = cs.getElementHandlers(args[0]);
		for (int i = 0; i < v.size(); i++) {
		    ControlSocket.HandlerInfo hi = (ControlSocket.HandlerInfo) v.elementAt(i);
		    System.out.print(hi.handlerName + "\t");
		    if (hi.canRead)
			System.out.print("r");
		    if (hi.canWrite)
			System.out.print("w");
		    System.out.println();
		}
	    } else {
		// dump router info
		System.out.println("Click version: " + cs.getRouterVersion().trim());
		System.out.print("Router classes: ");
		Vector v = cs.getRouterClasses();
		for (int i = 0; i < v.size(); i++)
		    System.out.print(v.elementAt(i) + " ");
		System.out.println();
		System.out.println("Router config:");
		System.out.print(cs.getRouterConfig());
		System.out.print("Config element names: ");
		v = cs.getConfigElementNames();
		for (int i = 0; i < v.size(); i++)
		    System.out.print(v.elementAt(i) + " ");
		System.out.println();
		System.out.print("Router packages: ");
		v = cs.getRouterPackages();
		for (int i = 0; i < v.size(); i++)
		    System.out.print(v.elementAt(i) + " ");
		System.out.println();
		System.out.print("Config requirements: ");
		v = cs.getConfigRequirements();
		for (int i = 0; i < v.size(); i++)
		    System.out.print(v.elementAt(i) + " ");
		System.out.println();	
	    }
	} catch (IOException ex) {
	    System.out.println("I/O error calling ControlSocket: " + ex.getMessage());
	    System.exit(1);
	} catch (ClickException ex) {
	    System.out.println(ex.getMessage());
	    System.exit(1);
	}
    }
}