admin.java

简易防火墙代码

/******************************************************************
*** File Admin.java 
***
***/

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

// 
// Class:     Admin
// Abstract:  The admin thread listens on admin socket and handle all
//            communications with the remote administrator.
//

public class Admin extends Thread
{
	//
	// Member variables
	//

	ServerSocket adminSocket = null;
	Socket appletSocket = null;
	String passwordCandidate = null;
	DataInputStream in = null;
	DataOutputStream out = null;
	Config config = null;
	Cache cache;
	
	
	//
	// Public methods
	//

	//
	// Constructor
	//
	Admin(Config configObject, Cache cacheManager)
	{
		try
		{
			config = configObject;
			cache = cacheManager;
			adminSocket = new ServerSocket(0);
			config.setAdminPort(adminSocket.getLocalPort());
		}
		catch (IOException e)
		{
			System.out.println("Error opening admin socket");
		}
	}


	//
	// Handle communications with remote administrator
	//
	public void run()
	{
		while(true)
		{
			try
			{
				appletSocket = adminSocket.accept();
				in = new DataInputStream(appletSocket.getInputStream());
				out = new DataOutputStream(appletSocket.getOutputStream());

				do
				{
					// Read password candidate sent by applet
					String passwordCandidate = in.readLine();

					// Send applet ack/nack on password
					if (config.getPassword().equals(passwordCandidate))
					{
						out.writeBytes("ACCEPT\n");
						break;
					}
					else
					{
						out.writeBytes("REJECT\n");
					}
					out.flush();
				}
				while (true);

				//
				// Password is OK, so let's send the administrator the
				// parameters values and read his new values
				//
				while(true)
				{
					out.writeBytes(config.toString());
					out.flush();

					config.parse(in.readLine());
					System.out.println("Configuration changed by administrator.");

					// Administrator wants to clean the cache
					if (config.getCleanCache())
					{
						cache.clean();
						config.setCleanCache(false); //no need to clean again
					}
				}
			}
			catch (Exception e)
			{
				//
				// This line was reached because the administrator closed
				// the connection with the proxy. That's fine, we are now
				// available for another administrator to log in.
				//
				System.out.println("Connection with administrator closed.");
			}
			finally
			{
				try
				{
					out.close();
					in.close();
				}
				catch(Exception exc)
				{}
			}
		}//while
	} 
}