moduletelnetimpl.java

一个非常好的ssh客户端实现

/******************************************************************************
 *
 * Copyright (c) 1999-2003 AppGate Network Security AB. All Rights Reserved.
 * 
 * This file contains Original Code and/or Modifications of Original Code as
 * defined in and that are subject to the MindTerm Public Source License,
 * Version 2.0, (the 'License'). You may not use this file except in compliance
 * with the License.
 * 
 * You should have received a copy of the MindTerm Public Source License
 * along with this software; see the file LICENSE.  If not, write to
 * AppGate Network Security AB, Otterhallegatan 2, SE-41118 Goteborg, SWEDEN
 *
 *****************************************************************************/

package com.mindbright.application;

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

import java.awt.Frame;

import com.mindbright.net.telnet.TelnetTerminalAdapter;
import com.mindbright.ssh2.SSH2InternalChannel;
import com.mindbright.ssh2.SSH2Channel;
import com.mindbright.terminal.Terminal;
import com.mindbright.terminal.TerminalWin;
import com.mindbright.terminal.LineReaderTerminal;
import com.mindbright.terminal.TerminalFrameTitle;

public class ModuleTelnetImpl extends ModuleBaseTerminal {
    private String                remoteHost;
    private int                   remotePort;
    private SSH2InternalChannel   channel;
    private TelnetTerminalAdapter telnetAdapter;
    private InputStream           telnetIn;
    private OutputStream          telnetOut;
    private LineReaderTerminal    lineReader;
    private boolean               localConnect;
    private Socket                socket;

    protected class ChaffedTelnet extends TelnetTerminalAdapter {
	
	public ChaffedTelnet(InputStream in, OutputStream out,
			     Terminal terminal)
	{
	    super(in, out, terminal);
	}

	protected void sendFakeChar() {
	    if(channel != null) {
		/*
		 * 5 bytes of "ignore-payload" makes packet same size as one
		 * byte channel data (i.e. a key-press). 
		 */
		byte[] chaff = new byte[] { 1, 2, 3, 4, 5 };
		channel.getConnection().getTransport().sendIgnore(chaff);
	    }
	}

    }

    public void runTerminal(MindTermApp mindterm, TerminalWin terminal,
			    Frame frame, TerminalFrameTitle frameTitle)
    {
	try {
	    remoteHost = mindterm.getProperty("module.telnet.host");
	    remotePort = getPort(mindterm.getProperty("module.telnet.port"));

	    localConnect = true;
	    
	    if(remoteHost == null) {
		if(!(mindterm.isConnected() &&
		     (mindterm.getConnection() != null))) {
		    terminal.write("Not connected to ssh2 server, can only make direct connections.\r\n");
		} else {
		    terminal.write("Prefix hostname with '|' to make a tunneled connection.\r\n");
		}
		lineReader = new LineReaderTerminal(terminal);
		remoteHost = lineReader.promptLine("\r\nremote host[:port] : ",
						   null, false);
		if(remoteHost.trim().length() == 0) {
		    return;
		}

		if(remoteHost.charAt(0) == '|') {
		    localConnect = false;
		    remoteHost = remoteHost.substring(1, remoteHost.length());
		}

		lineReader.detach();
	    }

	    int i = remoteHost.indexOf(':');
	    if(i != -1) {
		remotePort = getPort(remoteHost.substring(i + 1));
		remoteHost = remoteHost.substring(0, i);
	    }

	    if(localConnect) {
		try {
		    socket    = new Socket(remoteHost, remotePort);
		    telnetIn  = socket.getInputStream();
		    telnetOut = socket.getOutputStream();
		} catch (Exception e) {
		    mindterm.alert("Local connection failed: " +
				   e.getMessage());
		    return;
		}
	    } else {
		channel =
		    mindterm.getConnection().newLocalInternalForward(remoteHost,
								     remotePort);

		if(channel.openStatus() != SSH2Channel.STATUS_OPEN) {
		    mindterm.alert("Failed to open tunnel for telnet");
		    return;
		}

		telnetIn  = channel.getInputStream();
		telnetOut = channel.getOutputStream();
	    }

	    frameTitle.setTitleName("telnet@" + remoteHost + (remotePort != 23 ?
							      (":" + remotePort)
							      : ""));

	    telnetAdapter = new ChaffedTelnet(telnetIn, telnetOut, terminal);

	    if(useChaff()) {
		telnetAdapter.startChaff();
	    }

	    telnetAdapter.getTelnetNVT().getThread().join();
	    if(telnetAdapter.isBuffered()) {
		lineReader = new LineReaderTerminal(terminal);
		lineReader.promptLine("\n\rTelnet session was closed, press <return> to close window", null,
				      false);
	    }

	    telnetAdapter.stopChaff();

	} catch (Exception e) {
	    /* don't care */
	}
    }

    protected boolean closeOnDisconnect() {
	return !localConnect;
    }

    private int getPort(String port) {
	int p;
	try {
	    p = Integer.parseInt(port);
	} catch (Exception e) {
	    p = 23;
	}
	return p;
    }

    public String getTitle() {
	return mindterm.getAppName() + " - " + "Telnet (not connected)";
    }

    public boolean isAvailable(MindTermApp mindterm) {
	return true;
    }

    protected boolean haveMenus() {
	return Boolean.valueOf(mindterm.getProperty("module.telnet.havemenus")).
	    booleanValue();    
    }

    public void doClose() {
	if(telnetOut != null) {
	    try { telnetOut.close(); } catch (IOException ee) { }
	}
	if(telnetIn != null) {
	    try { telnetIn.close(); } catch (IOException ee) { }
	}
	if(channel != null) {
	    channel.close();
	}
	if(socket != null) {
	    try { socket.close(); } catch (IOException ee) { }
	}
	if(lineReader != null) {
	    lineReader.breakPromptLine("");
	}
    }

    protected ModuleBaseTerminal newInstance() {
	return new ModuleTelnetImpl();
    }

}