ServerAuthenticator.java

/*
 * This file is part of the OWASP Proxy, a free intercepting proxy library.
 * Copyright (C) 2008-2010 Rogan Dawes <rogan@dawes.za.net>
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to:
 * The Free Software Foundation, Inc., 
 * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */

package org.owasp.proxy.socks.impl;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;

/**
 * Classes implementing this interface should provide socks server with
 * authentication and authorization of users.
 **/
public interface ServerAuthenticator {

	/**
	 * This method is called when a new connection accepted by the server.
	 * <p>
	 * At this point no data have been extracted from the connection. It is
	 * responsibility of this method to ensure that the next byte in the stream
	 * after this method have been called is the first byte of the socks request
	 * message. For SOCKSv4 there is no authentication data and the first byte
	 * in the stream is part of the request. With SOCKSv5 however there is an
	 * authentication data first. It is expected that implementations will
	 * process this authentication data.
	 * <p>
	 * If authentication was successful an instance of ServerAuthentication
	 * should be returned, it later will be used by the server to perform
	 * authorization and some other things. If authentication fails null should
	 * be returned, or an exception may be thrown.
	 * 
	 * @param s
	 *            Accepted Socket.
	 * @return An instance of ServerAuthenticator to be used for this connection
	 *         or null
	 */
	ServerAuthenticator startSession(Socket s) throws IOException;

	/**
	 * This method should return input stream which should be used on the
	 * accepted socket.
	 * <p>
	 * SOCKSv5 allows to have multiple authentication methods, and these methods
	 * might require some kind of transformations being made on the data.
	 * <p>
	 * This method is called on the object returned from the startSession
	 * function.
	 */
	InputStream getInputStream();

	/**
	 * This method should return output stream to use to write to the accepted
	 * socket.
	 * <p>
	 * SOCKSv5 allows to have multiple authentication methods, and these methods
	 * might require some kind of transformations being made on the data.
	 * <p>
	 * This method is called on the object returned from the startSession
	 * function.
	 */
	OutputStream getOutputStream();

	/**
	 * This method is called when a request have been read.
	 * <p>
	 * Implementation should decide whether to grant request or not. Returning
	 * true implies granting the request, false means request should be
	 * rejected.
	 * <p>
	 * This method is called on the object returned from the startSession
	 * function.
	 * 
	 * @param msg
	 *            Request message.
	 * @return true to grant request, false to reject it.
	 */
	boolean checkRequest(ProxyMessage msg);

	/**
	 * This method is called when session is completed. Either due to normal
	 * termination or due to any error condition.
	 * <p>
	 * This method is called on the object returned from the startSession
	 * function.
	 */
	void endSession();
}