sshlistenchannel.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.ssh;

import java.net.*;
import java.io.*;

public class SSHListenChannel extends SSHChannel {
  static boolean allowRemoteConnect = false;

  static final int LISTEN_QUEUE_SIZE = 16;

  SSHChannelController controller;

  ServerSocket listenSocket;
  String       remoteHost;
  int          remotePort;
  InetAddress  localHost1;
  InetAddress  localHost2;

  boolean temporaryListener;

  public SSHListenChannel(String localHost, int localPort,
			  String remoteHost, int remotePort,
			  SSHChannelController controller)
    throws IOException {
    super(SSH.LISTEN_CHAN_NUM);
    this.controller         = controller;
    try {
	this.listenSocket = new ServerSocket(localPort, LISTEN_QUEUE_SIZE,
					     InetAddress.getByName(localHost));
    } catch (IOException e) {
	throw new IOException("Error setting up local forward on port " +
			      localPort + ", " + e.getMessage());
    }
    this.remoteHost         = remoteHost;
    this.remotePort         = remotePort;

    this.localHost1 = InetAddress.getLocalHost();
    this.localHost2 = InetAddress.getByName("127.0.0.1");
  }

  public int getListenPort() {
    return listenSocket.getLocalPort();
  }

  public String getListenHost() {
    return listenSocket.getInetAddress().getHostAddress();
  }

  public static synchronized void setAllowRemoteConnect(boolean val) {
    allowRemoteConnect = val;
  }

  static synchronized boolean getAllowRemoteConnect() {
    return allowRemoteConnect;
  }

  public SSHTunnel newTunnel(Socket ioSocket, int channelId, int remoteChannelId,
			     SSHChannelController controller) throws IOException {
    return new SSHTunnel(ioSocket, channelId, remoteChannelId, controller);
  }

  public void setTemporaryListener(boolean val) {
    temporaryListener = val;
  }

  public void serviceLoop() throws IOException {

    SSH.log("Starting listen-chan: " + listenSocket.getLocalPort());

    try {
	for(;;) {
	    Socket  fwdSocket = listenSocket.accept();

	    if(!getAllowRemoteConnect() &&
	       !(fwdSocket.getInetAddress().equals(localHost1) ||
		 fwdSocket.getInetAddress().equals(localHost2))) {
		controller.alert("Remote connect to local tunnel rejected: " + fwdSocket.getInetAddress());
		fwdSocket.close();
		continue;
	    }

	    SSHPduOutputStream respPdu =
		new SSHPduOutputStream(SSH.MSG_PORT_OPEN,
				       controller.sndCipher,
				       controller.sndComp,
				       SSH.secureRandom());

	    int newChan      = controller.newChannelId();
	    SSHTunnel tunnel = newTunnel(fwdSocket,
					 newChan, SSH.UNKNOWN_CHAN_NUM,
					 controller);
	    controller.addTunnel(tunnel);
	    tunnel.setRemoteDesc(remoteHost + ":" + remotePort);

	    respPdu.writeInt(newChan);
	    respPdu.writeString(remoteHost);
	    respPdu.writeInt(remotePort);

	    SSH.log("got connect for: " + remoteHost + " : " + remotePort + ", " + newChan);

	    //
	    // !!! TODO: check this !!! if(controller.haveHostInFwdOpen())
	    //
	    respPdu.writeString(fwdSocket.getInetAddress().getHostAddress());

	    controller.transmit(respPdu);

	    if(temporaryListener)
		break;
	}
    } finally {
	listenSocket.close();
    }
  }

  public void forceClose() {
      if(isAlive()) {
	  stop();
      }
      try {
	  listenSocket.close();
      } catch (IOException e) {
      }
  }

}