pop3protocol.java

StandBayeMail

/**
 * <p>Title: StandBayeMail </p>
 * <p>Description: A bayesian spam filter</p>
 * <p>Copyright: Copyright (c) 2004 by Luca M. Viola</p>
 * <p>Company: 3AM.it</p>
 * @author Luca M. Viola <[e-mail]>
 * @version 1.0


  This program is free software; you can redistribute it and/or
  modify it under the terms of the GNU General Public License
  as published by the Free Software Foundation; either version 2
  of the License, or (at your option) any later version.

  This program 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 General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */
package pop3proxy;

import java.net.*;
import StandBayeMail.*;
import java.io.File;

class Pop3Protocol implements Runnable
{
  protected String user;
  protected SocketWrapper client = null;
  protected SocketWrapper server = null;
  protected ServerMapper userContainer = null;
  protected Pop3StateMachine sm = new Pop3StateMachine();

  Logger trace;
  StandBayeMail sd;

  public Pop3Protocol(Socket socket, ServerMapper userContainer, Logger trace,StandBayeMail sd)
  {
    try
    {
      client = new LoggedSocketWrapper(socket, trace, Logger.CLIENT);
      this.userContainer = userContainer;
      this.trace = trace;
      this.sd=sd;
      new Thread(this).start();
    }
    catch (Exception e)
    {
    }
  }

  public void close()
  {
    if (client != null)
    {
      client.close();
      client = null;
    }

    if (server != null)
    {
      server.close();
      server = null;
    }
  }

  public void run()
  {
    try
    {
      client.write("+OK POP3 bayesian proxy server ready", true);
      String line;

      while (client != null)
      {
        if ( (line = client.read()) == null) break;
        execute(line);
      }
    }
    catch (Exception e)
    {
      e.printStackTrace();
    }
    close();
    trace.log(Logger.PROXY,"CONNECTION CLOSED (" + (new java.util.Date()) +")");
  }

  protected void execute(String line) throws Exception
  {
    String command = line;
    String arguments = new String();

    int space = line.indexOf(' ');

    if (space != -1)
    {
      command = line.substring(0, space);
      command = command.toUpperCase();
      arguments = line.substring(space + 1);
    }

    if (command.compareTo("USER") == 0)
    {
      execute_USER(arguments);
    }
    else if (command.compareTo("PASS") == 0)
    {
      execute_PASS(arguments);
    }
    else if (command.compareTo("DELE") == 0)
    {
      execute_DELE(arguments);
    }
    else if (command.compareTo("LIST") == 0)
    {
      execute_LIST(arguments);
    }
    else if (command.compareTo("QUIT") == 0)
    {
      execute_QUIT();
    }
    else if (command.compareTo("RETR") == 0)
    {
      execute_RETR(arguments);
    }
    else if (command.compareTo("STAT") == 0)
    {
      execute_STAT();
    }
    else if (command.compareTo("NOOP") == 0)
    {
      execute_NOOP();
    }
    else if (command.compareTo("UIDL") == 0)
    {
      execute_UIDL(arguments);
    }
    else if (command.compareTo("RSET") == 0)
    {
      execute_RSET();
    }
    else if (command.compareTo("TOP") == 0)
    {
      execute_TOP(arguments);
    }
    else if (command.compareTo("APOP") == 0)
    {
      client.write("-ERR Not implemented");
    }
    else
    {
      client.write("-ERR unknown command");
    }

    if (client != null)
    {
      client.flush();

    }
  }

  void execute_USER(String name) throws Exception
  {
    sm.checkState(sm.STATE_AUTH);

    String serverName = userContainer.getServer(name);

    if (serverName == null)
    {
      client.write("-ERR invalid username", true);
      close();
    }
    else
    {
      try
      {
        server = new LoggedSocketWrapper(serverName, trace, Logger.SERVER);
        String welcome = server.read();

        if (!welcome.startsWith("+OK"))
        {
          throw new Exception(welcome);
        }
        client.write(server.writeread("USER " + name));
      }
      catch (Exception e)
      {
        client.write("-ERR invalid username (2)", true);
        close();
      }
    }
  }

  void execute_PASS(String password) throws Exception
  {
    sm.checkState(sm.STATE_AUTH);
    String response = server.writeread("PASS " + password);
    if (response.startsWith("+OK"))
    {
      sm.setState(sm.STATE_ACTION);
    }
    client.write(response);
  }

  void execute_NOOP() throws Exception
  {
    sm.checkState(sm.STATE_ACTION);
    client.write(server.writeread("NOOP"));
  }

  void execute_QUIT() throws Exception
  {
    if (sm.getState() == sm.STATE_ACTION)
    {
      sm.setState(sm.STATE_QUIT);
    }
    client.write(server.writeread("QUIT"));
    close();
  }

  void execute_STAT() throws Exception
  {
    sm.checkState(sm.STATE_ACTION);
    client.write(server.writeread("STAT"));
  }

  void execute_DELE(String arg) throws Exception
  {
    sm.checkState(sm.STATE_ACTION);
    client.write(server.writeread("DELE " + arg));
  }

  // Insert a  new header at the end of the header list
  private StringBuffer insHeader( String header,StringBuffer mail )
  {
    int last=0,pos=0;
    String _mail=mail.toString();

/*
    while( pos!=-1 )
    {
      pos = _mail.indexOf(": ",pos+1);
      if( pos!=-1 ) last=pos;
    }
 */
    int eol=_mail.indexOf("\r\n\r\n",last);
    if( eol!=-1 )
        mail.replace(eol,eol+4, "\r\n" + header + "\r\n\r\n");
    return mail;
  }

  void execute_RETR(String message_id) throws Exception
  {
    sm.checkState(sm.STATE_ACTION);
    String response = server.writeread("RETR " + message_id);
    String backup = response;
    if (response.startsWith("+OK"))
    {
      StringBuffer body = new StringBuffer("");

      while (true)
      {
        response = server.read();
        if (response.compareTo(".") == 0)
        {
          break;
        }
        body.append(response);
        body.append("\r\n");
      }
      String _body = body.toString();
      Statistics st = sd.calculateSpamicity(Pop3Proxy.getCurrentWDir()+File.separator+"goodlist.sps",
                                            Pop3Proxy.getCurrentWDir()+File.separator+"spamlist.sps", _body);
      if (st.spamicity >= BayesianFilter.getSpamicityThreshold())
      {
        String subjHdr = "Subject: ";
        int subjpos = _body.indexOf(subjHdr);
        if( subjpos==-1 )
        {
          body=insHeader(subjHdr,body );
          _body=body.toString();
          subjpos = _body.indexOf(subjHdr);
        }
        if( subjpos!=-1 )
          body.replace(subjpos, subjpos + subjHdr.length(), subjHdr + "[SPAM] ");
        String spamhdr = "X-StandBayeMail-Spamicity: " + st.spamicity;
        body=insHeader(spamhdr,body);
        _body = body.toString();
        response = "+OK " + _body.length() + " bytes";
        client.write(response);
      }
      else
        client.write(backup);
      client.write(_body + ".");
      client.flush();
      java.text.DecimalFormat df=new java.text.DecimalFormat("0.################################");
      String d=df.format(st.spamicity);
      trace.log(Logger.PROXY,"Spamicity: "+d);
      for( int k=0; k<st.extrema.length; k++ )
        trace.log(Logger.PROXY,st.extrema[k].key+"="+df.format(st.extrema[k].prob));
      return;
    }
    client.write(backup,true);
  }

  void execute_LIST(String msg) throws Exception
  {
    sm.checkState(sm.STATE_ACTION);

    if (msg.length() > 0)
    {
      client.write(server.writeread("LIST " + msg));
    }
    else
    {
      String response = server.writeread("LIST");

      client.write(response);
      if (response.startsWith("+OK"))
      {
        while (true)
        {
          response = server.read();
          client.write(response);
          if (response.compareTo(".") == 0) break;
        }
      }
    }
  }

  void execute_UIDL(String arg) throws Exception
  {
    sm.checkState(sm.STATE_ACTION);

    if (arg.length() > 0)
    {
      client.write(server.writeread("UIDL " + arg));
    }
    else
    {
      String request = server.writeread("UIDL");

      client.write(request);

      if (request.startsWith("+OK"))
      {
        while (true)
        {
          request = server.read();
          client.write(request);
          if (request.compareTo(".") == 0) break;
        }
      }
    }
  }

  void execute_RSET() throws Exception
  {
    sm.checkState(sm.STATE_ACTION);
    client.write(server.writeread("RSET"));
  }

  void execute_TOP(String arg) throws Exception
  {
    sm.checkState(sm.STATE_ACTION);
    client.write(server.writeread("TOP " + arg));
  }
}