tcpProxy.py

#!/usr/bin/env python2
import sys;
import socket;
import threading as thread;

def serverLoop(local_host, local_port, remote_host, remote_port, receive_first):
    server = socket.socket(socket.AF_INET, socket.SOCK_STREAM);

    try:
        server.bind((local_host, local_port));
    except:
        print "[!!] Failed to listen on %s:%d" % (local_host, local_port);
        print "[!!] Check for other listening sockets or correct permissions";
        sys.exit(0);

    print "[*] Listening on %s:%d" % (local_host, local_port);
    server.listen(5);

    while True:
        client_socket, addr = server.accept();
        print "[==>] Received connection from %s:%d" % (addr[0], addr[1]);
        proxy_thread = thread.Thread(target=proxyHandler, args=(client_socket, remote_host, remote_port, receive_first));
        proxy_thread.start();


def proxyHandler(client_socket, remote_host, remote_port, receive_first):
    remote_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM);
    remote_socket.connect((remote_host, remote_port));

    if receive_first:
        remote_buffer = receiveFrom(remote_socket);
        hexdump(remote_buffer);
        remote_buffer = responseHandler(remote_buffer);
        if len(remote_buffer):
            print "[<==] Sending %d bytes to localhost." % len(remote_buffer);
            client_socket.send(remote_buffer);

    while True:
        local_buffer = receiveFrom(client_socket);
        if len(local_buffer):
            print "[==>] Received %d bytes from localhost." % len(local_buffer);
            hexdump(local_buffer);
            local_buffer = requestHandler(local_buffer);
            remote_socket.send(local_buffer);
            print "[==>] Sent to remote.";

        remote_buffer = receiveFrom(remote_socket);
        if len(remote_buffer):
            print "[<==] Received %d bytes from remote." % len(remote_buffer);
            hexdump(remote_buffer);
            remote_buffer = responseHandler(remote_buffer);
            client_socket.send(remote_buffer);
            print "[<==] Sent to localhost.";

        if not len(local_buffer) or not len(remote_buffer):
            client_socket.close();
            remote_socket.close();
            print "[*] No more data. Closing connection.";
            break;


# http://code.activestate.com/recipes/142812-hex-dumper/
def hexdump(src, length=16):
    result = [];
    digits = 4 if isinstance(src, unicode) else 2;
    for i in xrange(0, len(src), length):
        s = src[i:i+length];
        hexa = b' '.join(["%0*X" % (digits, ord(x)) for x in s]);
        text = b''.join([x if 0x20 <= ord(x) < 0x7F else b'.' for x in s]);
        result.append( b"%04X %-*s %s" % (i, length*(digits + 1), hexa, text) );

    print b'\n'.join(result);


def receiveFrom(connection):
    buffer = "";
    connection.settimeout(2);

    try:
        while True:
            data = connection.recv(4096);
            if not data:
                break;
            buffer += data;
    except: 
        pass;

    return buffer;


def requestHandler(buffer):
    return buffer;


def responseHandler(buffer):
    return buffer;


def main():
    if len(sys.argv[1:]) != 5:
        print "Use with: ./tcpProxy.py [localhost] [localport] [remotehost] [remoteport] [receive_first]";
        print "Example: ./tcpProxy.py 127.0.0.1 9000 10.12.132.1 9000 True";
        sys.exit(0);

    local_host    = sys.argv[1];
    local_port    = int(sys.argv[2]);
    remote_host   = sys.argv[3];
    remote_port   = int(sys.argv[4]);
    receive_first = sys.argv[5];

    if "True" in receive_first:
        receive_first = True;
    else:
        receive_first = False;

    serverLoop(local_host, local_port, remote_host, remote_port, receive_first);

main();