import sys
import socket
import threading
def server_loop(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 incoming connecction from %s:%d" % (addr[0],addr[1])
		proxy_thread = threading.Thread(target=proxy_handler, args=(client_socket,remote_host,remote_port,receive_first))
		proxy_thread.start()

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 receive_from(connection):
	buffer=""
	connection.settimeout(2)
	try:
		while True:
			data=connection.recv(4096)
			if not data:
				break
			buffer += data
	except:
		pass
	return buffer

def request_handler(buffer):
	#modifica  requests destinados al host remoto
	#hace lo mismo que el response_handler, sirve para modificar las tramas a la salida del trafico
	return buffer

def response_handler (buffer):
	#modificar respuestas destinadas para el host local
	#adentro de esta funcion se puede modificar el contenido del paquete, probar cuestiones de autenticacion o lo que sea
	return buffer

def proxy_handler (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))
	#1
	if receive_first:
	#2
		remote_buffer=receive_from(remote_socket)
	#3
		hexdump(remote_buffer)
	#4
		remote_buffer = response_handler(remote_buffer)
		if len(remote_buffer):
			print "[<==] Sending %d bytes to localhost." % len(remote_buffer)
			client_socket.send(remote_buffer)
	while True:
		local_buffer = receive_from(client_socket)
		if len(local_buffer):
			print "[==>] Received %d bytes from localhost." % len(local_buffer)
			hexdump(local_buffer)
			local_buffer=request_handler(local_buffer)
			remote_socket.send(local_buffer)
			print "[==>] Enviado al remoto."
		remote_buffer = receive_from(remote_socket)
		if len(remote_buffer):
			print "[<==] Recibiendo %d bytes del remoto." % len(remote_buffer)
			hexdump(remote_buffer)
			remote_buffer=response_handler(remote_buffer)
			client_socket.send(remote_buffer)
			print "[<==] Enviado al localhost."
	#5
#		if not len(local_buffer) or not len(remote_buffer):
#			client_socket.close()
#			remote_socket.close()
#			print "[*] No hay mas datos, cerrando conexion"
#			break

def main ():
	if len(sys.argv[1:]) !=5 :
		print "SI LLEGASTE AQUI ES QUE NO SABES USAR EL PROGRAMA"
		print "USO: python proxy.py [localhost] [local_port] [remotehost] [remoteport] [receive_first(esto depende del servidor que se usa]"
		print "EJEMPLO: pytho proxy.py 127.0.0.1 9000 10.12.132.1 900 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
	server_loop(local_host,local_port,remote_host,remote_port,receive_first)
main()
