core/src/main/java/org/apache/ftpserver/impl/IODataConnectionFactory.java - mina-ftpserver - Git at Google

 /*
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
  * distributed with this work for additional information
  * regarding copyright ownership.  The ASF licenses this file
  * to you under the Apache License, Version 2.0 (the
  * "License"); you may not use this file except in compliance
  * with the License.  You may obtain a copy of the License at
  *
  *  http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing,
  * software distributed under the License is distributed on an
  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  * KIND, either express or implied.  See the License for the
  * specific language governing permissions and limitations
  * under the License.
  */

 package org.apache.ftpserver.impl;

 import java.net.InetAddress;
 import java.net.InetSocketAddress;
 import java.net.ServerSocket;
 import java.net.Socket;
 import java.net.SocketAddress;
 import java.net.UnknownHostException;

 import javax.net.ssl.SSLSocket;
 import javax.net.ssl.SSLSocketFactory;

 import org.apache.ftpserver.DataConnectionConfiguration;
 import org.apache.ftpserver.DataConnectionException;
 import org.apache.ftpserver.ftplet.DataConnection;
 import org.apache.ftpserver.ftplet.FtpException;
 import org.apache.ftpserver.ssl.ClientAuth;
 import org.apache.ftpserver.ssl.SslConfiguration;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;

 /**
  * <strong>Internal class, do not use directly.</strong>
  *
  * We can get the FTP data connection using this class. It uses either PORT or PASV command.
  *
  * @author <a href="http://mina.apache.org">Apache MINA Project</a>
  */
 public class IODataConnectionFactory implements ServerDataConnectionFactory {

     private final Logger LOG = LoggerFactory.getLogger(IODataConnectionFactory.class);

     private FtpServerContext serverContext;

     private Socket dataSoc;

     ServerSocket servSoc;

     InetAddress address;

     int port = 0;

     long requestTime = 0L;

     boolean passive = false;

     boolean secure = false;

     private boolean isZip = false;

     InetAddress serverControlAddress;

     FtpIoSession session;

     public IODataConnectionFactory(final FtpServerContext serverContext, final FtpIoSession session) {
         this.session = session;
         this.serverContext = serverContext;
         if ((session != null) && (session.getListener() != null) && session.getListener().getDataConnectionConfiguration().isImplicitSsl()) {
             secure = true;
         }
     }

     /**
      * Close data socket. This method must be idempotent as we might call it multiple times during disconnect.
      */
     public synchronized void closeDataConnection() {

     // close client socket if any
     if (dataSoc != null) {
         try {
         dataSoc.close();
         } catch (Exception ex) {
         LOG.warn("FtpDataConnection.closeDataSocket()", ex);
         }
         dataSoc = null;
     }

     // close server socket if any
     if (servSoc != null) {
         try {
         servSoc.close();
         } catch (Exception ex) {
         LOG.warn("FtpDataConnection.closeDataSocket()", ex);
         }

         if (session != null) {
         DataConnectionConfiguration dcc = session.getListener().getDataConnectionConfiguration();
         if (dcc != null) {
             dcc.releasePassivePort(port);
         }
         }

         servSoc = null;
     }

     // reset request time
     requestTime = 0L;
     }

     /**
      * Port command.
      */
     public synchronized void initActiveDataConnection(final InetSocketAddress address) {
         // close old sockets if any
         closeDataConnection();

         // set variables
         passive = false;
         this.address = address.getAddress();
         port = address.getPort();
         requestTime = System.currentTimeMillis();
         }

         private SslConfiguration getSslConfiguration() {
         DataConnectionConfiguration dataCfg = session.getListener().getDataConnectionConfiguration();

         SslConfiguration configuration = dataCfg.getSslConfiguration();

         // fall back if no configuration has been provided on the data connection config
         if (configuration == null) {
             configuration = session.getListener().getSslConfiguration();
         }

         return configuration;
     }

     /**
      * Initiate a data connection in passive mode (server listening).
      */
     public synchronized InetSocketAddress initPassiveDataConnection() throws DataConnectionException {
         LOG.debug("Initiating passive data connection");
         // close old sockets if any
         closeDataConnection();

         // get the passive port
         int passivePort = session.getListener().getDataConnectionConfiguration().requestPassivePort();
         if (passivePort == -1) {
             servSoc = null;
             throw new DataConnectionException("Cannot find an available passive port.");
         }

         // open passive server socket and get parameters
         try {
             DataConnectionConfiguration dataCfg = session.getListener().getDataConnectionConfiguration();

             String passiveAddress = dataCfg.getPassiveAddress();

             if (passiveAddress == null) {
                 address = serverControlAddress;
             } else {
                 address = resolveAddress(dataCfg.getPassiveAddress());
             }

             if (secure) {
                 LOG.debug("Opening SSL passive data connection on address \"{}\" and port {}", address, passivePort);
                 SslConfiguration ssl = getSslConfiguration();

                 if (ssl == null) {
                     throw new DataConnectionException("Data connection SSL required but not configured.");
                 }

                 // this method does not actually create the SSL socket, due to a JVM bug
                 // (https://issues.apache.org/jira/browse/FTPSERVER-241).
                 // Instead, it creates a regular
                 // ServerSocket that will be wrapped as a SSL socket in createDataSocket()
                 servSoc = new ServerSocket(passivePort, 0, address);
                 LOG.debug("SSL Passive data connection created on address \"{}\" and port {}", address, passivePort);
             } else {
                 LOG.debug("Opening passive data connection on address \"{}\" and port {}", address, passivePort);
                 servSoc = new ServerSocket(passivePort, 0, address);
                 LOG.debug("Passive data connection created on address \"{}\" and port {}", address, passivePort);
             }

             port = servSoc.getLocalPort();
             servSoc.setSoTimeout(dataCfg.getIdleTime() * 1000);

             // set different state variables
             passive = true;
             requestTime = System.currentTimeMillis();

             return new InetSocketAddress(address, port);
         } catch (Exception ex) {
             closeDataConnection();
             throw new DataConnectionException("Failed to initate passive data connection: " + ex.getMessage(), ex);
         }
     }

     /*
      * (non-Javadoc)
      *
      * @see org.apache.ftpserver.FtpDataConnectionFactory2#getInetAddress()
      */
     public InetAddress getInetAddress() {
         return address;
     }

     /*
      * (non-Javadoc)
      *
      * @see org.apache.ftpserver.FtpDataConnectionFactory2#getPort()
      */
     public int getPort() {
         return port;
     }

     /*
      * (non-Javadoc)
      *
      * @see org.apache.ftpserver.FtpDataConnectionFactory2#openConnection()
      */
     public DataConnection openConnection() throws Exception {
         return new IODataConnection(createDataSocket(), session, this);
     }

     /**
      * Get the data socket. In case of error returns null.
      */
     private synchronized Socket createDataSocket() throws Exception {
         // get socket depending on the selection
         dataSoc = null;
         DataConnectionConfiguration dataConfig = session.getListener().getDataConnectionConfiguration();
         try {
             if (!passive) {
                 if (secure) {
                     LOG.debug("Opening secure active data connection");
                     SslConfiguration ssl = getSslConfiguration();

                     if (ssl == null) {
                         throw new FtpException("Data connection SSL not configured");
                     }

                     // get socket factory
                     SSLSocketFactory socFactory = ssl.getSocketFactory();

                     // create socket
                     SSLSocket ssoc = (SSLSocket) socFactory.createSocket();
                     ssoc.setUseClientMode(false);

                     // initialize socket
                     if (ssl.getEnabledCipherSuites() != null) {
                         ssoc.setEnabledCipherSuites(ssl.getEnabledCipherSuites());
                     }

                     if (ssl.getEnabledProtocols() != null) {
                         ssoc.setEnabledProtocols(ssl.getEnabledProtocols());
                     }

                     dataSoc = ssoc;
                 } else {
                     LOG.debug("Opening active data connection");
                     dataSoc = new Socket();
                 }

                 dataSoc.setReuseAddress(true);

                 InetAddress localAddr = resolveAddress(dataConfig.getActiveLocalAddress());

                 // if no local address has been configured, make sure we use the same as the client connects from
                 if (localAddr == null) {
                     localAddr = ((InetSocketAddress) session.getLocalAddress()).getAddress();
                 }

                 SocketAddress localSocketAddress = new InetSocketAddress(localAddr, dataConfig.getActiveLocalPort());

                 LOG.debug("Binding active data connection to {}", localSocketAddress);
                 dataSoc.bind(localSocketAddress);

                 dataSoc.connect(new InetSocketAddress(address, port));
             } else {

             if (secure) {
                 LOG.debug("Opening secure passive data connection");
                 // this is where we wrap the unsecured socket as a SSLSocket. This is
                 // due to the JVM bug described in FTPSERVER-241.

                 // get server socket factory
                 SslConfiguration ssl = getSslConfiguration();

                 // we've already checked this, but let's do it again
                 if (ssl == null) {
                 throw new FtpException("Data connection SSL not configured");
                 }

                 SSLSocketFactory ssocketFactory = ssl.getSocketFactory();

                 Socket serverSocket = servSoc.accept();

                 SSLSocket sslSocket = (SSLSocket) ssocketFactory.createSocket(serverSocket, serverSocket.getInetAddress().getHostAddress(), serverSocket.getPort(), true);
                 sslSocket.setUseClientMode(false);

                 // initialize server socket
                 if (ssl.getClientAuth() == ClientAuth.NEED) {
                     sslSocket.setNeedClientAuth(true);
                 } else if (ssl.getClientAuth() == ClientAuth.WANT) {
                     sslSocket.setWantClientAuth(true);
                 }

                 if (ssl.getEnabledCipherSuites() != null) {
                     sslSocket.setEnabledCipherSuites(ssl.getEnabledCipherSuites());
                 }

                 if (ssl.getEnabledProtocols() != null) {
                     sslSocket.setEnabledProtocols(ssl.getEnabledProtocols());
                 }

                 dataSoc = sslSocket;
             } else {
                 LOG.debug("Opening passive data connection");

                 dataSoc = servSoc.accept();
             }

             if (dataConfig.isPassiveIpCheck()) {
                 // Let's make sure we got the connection from the same
                 // client that we are expecting
                 InetAddress remoteAddress = ((InetSocketAddress) session.getRemoteAddress()).getAddress();
                 InetAddress dataSocketAddress = dataSoc.getInetAddress();
                 if (!dataSocketAddress.equals(remoteAddress)) {
                 LOG.warn("Passive IP Check failed. Closing data connection from " + dataSocketAddress + " as it does not match the expected address " + remoteAddress);
                 closeDataConnection();
                 return null;
                 }
             }

             DataConnectionConfiguration dataCfg = session.getListener().getDataConnectionConfiguration();

             dataSoc.setSoTimeout(dataCfg.getIdleTime() * 1000);
             LOG.debug("Passive data connection opened");
             }
         } catch (Exception ex) {
             closeDataConnection();
             LOG.warn("FtpDataConnection.getDataSocket()", ex);
             throw ex;
         }
         dataSoc.setSoTimeout(dataConfig.getIdleTime() * 1000);

         // Make sure we initiate the SSL handshake, or we'll
         // get an error if we turn out not to send any data
         // e.g. during the listing of an empty directory
         if (dataSoc instanceof SSLSocket) {
             ((SSLSocket) dataSoc).startHandshake();
         }

         return dataSoc;
     }

     /*
      * (non-Javadoc) Returns an InetAddress object from a hostname or IP address.
      */
     private InetAddress resolveAddress(String host) throws DataConnectionException {
         if (host == null) {
             return null;
         } else {
             try {
             return InetAddress.getByName(host);
             } catch (UnknownHostException ex) {
             throw new DataConnectionException("Failed to resolve address", ex);
             }
         }
     }

     /*
      * (non-Javadoc)
      *
      * @see org.apache.ftpserver.DataConnectionFactory#isSecure()
      */
     public boolean isSecure() {
     return secure;
     }

     /**
      * Set the security protocol.
      */
     public void setSecure(final boolean secure) {
     this.secure = secure;
     }

     /*
      * (non-Javadoc)
      *
      * @see org.apache.ftpserver.DataConnectionFactory#isZipMode()
      */
     public boolean isZipMode() {
     return isZip;
     }

     /**
      * Set zip mode.
      */
     public void setZipMode(final boolean zip) {
     isZip = zip;
     }

     /**
      * Check the data connection idle status.
      */
     public synchronized boolean isTimeout(final long currTime) {

     // data connection not requested - not a timeout
     if (requestTime == 0L) {
         return false;
     }

     // data connection active - not a timeout
     if (dataSoc != null) {
         return false;
     }

     // no idle time limit - not a timeout
     int maxIdleTime = session.getListener().getDataConnectionConfiguration().getIdleTime() * 1000;
     if (maxIdleTime == 0) {
         return false;
     }

     // idle time is within limit - not a timeout
     if ((currTime - requestTime) < maxIdleTime) {
         return false;
     }

     return true;
     }

     /**
      * Dispose data connection - close all the sockets.
      */
     public void dispose() {
     closeDataConnection();
     }

     /**
      * Sets the server's control address.
      */
     public void setServerControlAddress(final InetAddress serverControlAddress) {
     this.serverControlAddress = serverControlAddress;
     }
 }
	/*
	* Licensed to the Apache Software Foundation (ASF) under one
	* or more contributor license agreements. See the NOTICE file
	* distributed with this work for additional information
	* regarding copyright ownership. The ASF licenses this file
	* to you under the Apache License, Version 2.0 (the
	* "License"); you may not use this file except in compliance
	* with the License. You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing,
	* software distributed under the License is distributed on an
	* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
	* KIND, either express or implied. See the License for the
	* specific language governing permissions and limitations
	* under the License.
	*/

	package org.apache.ftpserver.impl;

	import java.net.InetAddress;
	import java.net.InetSocketAddress;
	import java.net.ServerSocket;
	import java.net.Socket;
	import java.net.SocketAddress;
	import java.net.UnknownHostException;

	import javax.net.ssl.SSLSocket;
	import javax.net.ssl.SSLSocketFactory;

	import org.apache.ftpserver.DataConnectionConfiguration;
	import org.apache.ftpserver.DataConnectionException;
	import org.apache.ftpserver.ftplet.DataConnection;
	import org.apache.ftpserver.ftplet.FtpException;
	import org.apache.ftpserver.ssl.ClientAuth;
	import org.apache.ftpserver.ssl.SslConfiguration;
	import org.slf4j.Logger;
	import org.slf4j.LoggerFactory;

	/**
	* <strong>Internal class, do not use directly.</strong>
	*
	* We can get the FTP data connection using this class. It uses either PORT or PASV command.
	*
	* @author <a href="http://mina.apache.org">Apache MINA Project</a>
	*/
	public class IODataConnectionFactory implements ServerDataConnectionFactory {

	private final Logger LOG = LoggerFactory.getLogger(IODataConnectionFactory.class);

	private FtpServerContext serverContext;

	private Socket dataSoc;

	ServerSocket servSoc;

	InetAddress address;

	int port = 0;

	long requestTime = 0L;

	boolean passive = false;

	boolean secure = false;

	private boolean isZip = false;

	InetAddress serverControlAddress;

	FtpIoSession session;

	public IODataConnectionFactory(final FtpServerContext serverContext, final FtpIoSession session) {
	this.session = session;
	this.serverContext = serverContext;
	if ((session != null) && (session.getListener() != null) && session.getListener().getDataConnectionConfiguration().isImplicitSsl()) {
	secure = true;
	}
	}

	/**
	* Close data socket. This method must be idempotent as we might call it multiple times during disconnect.
	*/
	public synchronized void closeDataConnection() {

	// close client socket if any
	if (dataSoc != null) {
	try {
	dataSoc.close();
	} catch (Exception ex) {
	LOG.warn("FtpDataConnection.closeDataSocket()", ex);
	}
	dataSoc = null;
	}

	// close server socket if any
	if (servSoc != null) {
	try {
	servSoc.close();
	} catch (Exception ex) {
	LOG.warn("FtpDataConnection.closeDataSocket()", ex);
	}

	if (session != null) {
	DataConnectionConfiguration dcc = session.getListener().getDataConnectionConfiguration();
	if (dcc != null) {
	dcc.releasePassivePort(port);
	}
	}

	servSoc = null;
	}

	// reset request time
	requestTime = 0L;
	}

	/**
	* Port command.
	*/
	public synchronized void initActiveDataConnection(final InetSocketAddress address) {
	// close old sockets if any
	closeDataConnection();

	// set variables
	passive = false;
	this.address = address.getAddress();
	port = address.getPort();
	requestTime = System.currentTimeMillis();
	}

	private SslConfiguration getSslConfiguration() {
	DataConnectionConfiguration dataCfg = session.getListener().getDataConnectionConfiguration();

	SslConfiguration configuration = dataCfg.getSslConfiguration();

	// fall back if no configuration has been provided on the data connection config
	if (configuration == null) {
	configuration = session.getListener().getSslConfiguration();
	}

	return configuration;
	}

	/**
	* Initiate a data connection in passive mode (server listening).
	*/
	public synchronized InetSocketAddress initPassiveDataConnection() throws DataConnectionException {
	LOG.debug("Initiating passive data connection");
	// close old sockets if any
	closeDataConnection();

	// get the passive port
	int passivePort = session.getListener().getDataConnectionConfiguration().requestPassivePort();
	if (passivePort == -1) {
	servSoc = null;
	throw new DataConnectionException("Cannot find an available passive port.");
	}

	// open passive server socket and get parameters
	try {
	DataConnectionConfiguration dataCfg = session.getListener().getDataConnectionConfiguration();

	String passiveAddress = dataCfg.getPassiveAddress();

	if (passiveAddress == null) {
	address = serverControlAddress;
	} else {
	address = resolveAddress(dataCfg.getPassiveAddress());
	}

	if (secure) {
	LOG.debug("Opening SSL passive data connection on address \"{}\" and port {}", address, passivePort);
	SslConfiguration ssl = getSslConfiguration();

	if (ssl == null) {
	throw new DataConnectionException("Data connection SSL required but not configured.");
	}

	// this method does not actually create the SSL socket, due to a JVM bug
	// (https://issues.apache.org/jira/browse/FTPSERVER-241).
	// Instead, it creates a regular
	// ServerSocket that will be wrapped as a SSL socket in createDataSocket()
	servSoc = new ServerSocket(passivePort, 0, address);
	LOG.debug("SSL Passive data connection created on address \"{}\" and port {}", address, passivePort);
	} else {
	LOG.debug("Opening passive data connection on address \"{}\" and port {}", address, passivePort);
	servSoc = new ServerSocket(passivePort, 0, address);
	LOG.debug("Passive data connection created on address \"{}\" and port {}", address, passivePort);
	}

	port = servSoc.getLocalPort();
	servSoc.setSoTimeout(dataCfg.getIdleTime() * 1000);

	// set different state variables
	passive = true;
	requestTime = System.currentTimeMillis();

	return new InetSocketAddress(address, port);
	} catch (Exception ex) {
	closeDataConnection();
	throw new DataConnectionException("Failed to initate passive data connection: " + ex.getMessage(), ex);
	}
	}

	/*
	* (non-Javadoc)
	*
	* @see org.apache.ftpserver.FtpDataConnectionFactory2#getInetAddress()
	*/
	public InetAddress getInetAddress() {
	return address;
	}

	/*
	* (non-Javadoc)
	*
	* @see org.apache.ftpserver.FtpDataConnectionFactory2#getPort()
	*/
	public int getPort() {
	return port;
	}

	/*
	* (non-Javadoc)
	*
	* @see org.apache.ftpserver.FtpDataConnectionFactory2#openConnection()
	*/
	public DataConnection openConnection() throws Exception {
	return new IODataConnection(createDataSocket(), session, this);
	}

	/**
	* Get the data socket. In case of error returns null.
	*/
	private synchronized Socket createDataSocket() throws Exception {
	// get socket depending on the selection
	dataSoc = null;
	DataConnectionConfiguration dataConfig = session.getListener().getDataConnectionConfiguration();
	try {
	if (!passive) {
	if (secure) {
	LOG.debug("Opening secure active data connection");
	SslConfiguration ssl = getSslConfiguration();

	if (ssl == null) {
	throw new FtpException("Data connection SSL not configured");
	}

	// get socket factory
	SSLSocketFactory socFactory = ssl.getSocketFactory();

	// create socket
	SSLSocket ssoc = (SSLSocket) socFactory.createSocket();
	ssoc.setUseClientMode(false);

	// initialize socket
	if (ssl.getEnabledCipherSuites() != null) {
	ssoc.setEnabledCipherSuites(ssl.getEnabledCipherSuites());
	}

	if (ssl.getEnabledProtocols() != null) {
	ssoc.setEnabledProtocols(ssl.getEnabledProtocols());
	}

	dataSoc = ssoc;
	} else {
	LOG.debug("Opening active data connection");
	dataSoc = new Socket();
	}

	dataSoc.setReuseAddress(true);

	InetAddress localAddr = resolveAddress(dataConfig.getActiveLocalAddress());

	// if no local address has been configured, make sure we use the same as the client connects from
	if (localAddr == null) {
	localAddr = ((InetSocketAddress) session.getLocalAddress()).getAddress();
	}

	SocketAddress localSocketAddress = new InetSocketAddress(localAddr, dataConfig.getActiveLocalPort());

	LOG.debug("Binding active data connection to {}", localSocketAddress);
	dataSoc.bind(localSocketAddress);

	dataSoc.connect(new InetSocketAddress(address, port));
	} else {

	if (secure) {
	LOG.debug("Opening secure passive data connection");
	// this is where we wrap the unsecured socket as a SSLSocket. This is
	// due to the JVM bug described in FTPSERVER-241.

	// get server socket factory
	SslConfiguration ssl = getSslConfiguration();

	// we've already checked this, but let's do it again
	if (ssl == null) {
	throw new FtpException("Data connection SSL not configured");
	}

	SSLSocketFactory ssocketFactory = ssl.getSocketFactory();

	Socket serverSocket = servSoc.accept();

	SSLSocket sslSocket = (SSLSocket) ssocketFactory.createSocket(serverSocket, serverSocket.getInetAddress().getHostAddress(), serverSocket.getPort(), true);
	sslSocket.setUseClientMode(false);

	// initialize server socket
	if (ssl.getClientAuth() == ClientAuth.NEED) {
	sslSocket.setNeedClientAuth(true);
	} else if (ssl.getClientAuth() == ClientAuth.WANT) {
	sslSocket.setWantClientAuth(true);
	}

	if (ssl.getEnabledCipherSuites() != null) {
	sslSocket.setEnabledCipherSuites(ssl.getEnabledCipherSuites());
	}

	if (ssl.getEnabledProtocols() != null) {
	sslSocket.setEnabledProtocols(ssl.getEnabledProtocols());
	}

	dataSoc = sslSocket;
	} else {
	LOG.debug("Opening passive data connection");

	dataSoc = servSoc.accept();
	}

	if (dataConfig.isPassiveIpCheck()) {
	// Let's make sure we got the connection from the same
	// client that we are expecting
	InetAddress remoteAddress = ((InetSocketAddress) session.getRemoteAddress()).getAddress();
	InetAddress dataSocketAddress = dataSoc.getInetAddress();
	if (!dataSocketAddress.equals(remoteAddress)) {
	LOG.warn("Passive IP Check failed. Closing data connection from " + dataSocketAddress + " as it does not match the expected address " + remoteAddress);
	closeDataConnection();
	return null;
	}
	}

	DataConnectionConfiguration dataCfg = session.getListener().getDataConnectionConfiguration();

	dataSoc.setSoTimeout(dataCfg.getIdleTime() * 1000);
	LOG.debug("Passive data connection opened");
	}
	} catch (Exception ex) {
	closeDataConnection();
	LOG.warn("FtpDataConnection.getDataSocket()", ex);
	throw ex;
	}
	dataSoc.setSoTimeout(dataConfig.getIdleTime() * 1000);

	// Make sure we initiate the SSL handshake, or we'll
	// get an error if we turn out not to send any data
	// e.g. during the listing of an empty directory
	if (dataSoc instanceof SSLSocket) {
	((SSLSocket) dataSoc).startHandshake();
	}

	return dataSoc;
	}

	/*
	* (non-Javadoc) Returns an InetAddress object from a hostname or IP address.
	*/
	private InetAddress resolveAddress(String host) throws DataConnectionException {
	if (host == null) {
	return null;
	} else {
	try {
	return InetAddress.getByName(host);
	} catch (UnknownHostException ex) {
	throw new DataConnectionException("Failed to resolve address", ex);
	}
	}
	}

	/*
	* (non-Javadoc)
	*
	* @see org.apache.ftpserver.DataConnectionFactory#isSecure()
	*/
	public boolean isSecure() {
	return secure;
	}

	/**
	* Set the security protocol.
	*/
	public void setSecure(final boolean secure) {
	this.secure = secure;
	}

	/*
	* (non-Javadoc)
	*
	* @see org.apache.ftpserver.DataConnectionFactory#isZipMode()
	*/
	public boolean isZipMode() {
	return isZip;
	}

	/**
	* Set zip mode.
	*/
	public void setZipMode(final boolean zip) {
	isZip = zip;
	}

	/**
	* Check the data connection idle status.
	*/
	public synchronized boolean isTimeout(final long currTime) {

	// data connection not requested - not a timeout
	if (requestTime == 0L) {
	return false;
	}

	// data connection active - not a timeout
	if (dataSoc != null) {
	return false;
	}

	// no idle time limit - not a timeout
	int maxIdleTime = session.getListener().getDataConnectionConfiguration().getIdleTime() * 1000;
	if (maxIdleTime == 0) {
	return false;
	}

	// idle time is within limit - not a timeout
	if ((currTime - requestTime) < maxIdleTime) {
	return false;
	}

	return true;
	}

	/**
	* Dispose data connection - close all the sockets.
	*/
	public void dispose() {
	closeDataConnection();
	}

	/**
	* Sets the server's control address.
	*/
	public void setServerControlAddress(final InetAddress serverControlAddress) {
	this.serverControlAddress = serverControlAddress;
	}
	}