udp proxy

# -*- coding: utf-8 -*-
# 15/5/21
# create by: snower

import sys
import socket
import struct
from sevent import udp
from sevent import current

class Request(object):
    _caches = {}

    def __init__(self, conn, address):
        self.conn = conn
        self.address = address
        self.pconn = udp.Socket()
        self.pconn.on("data", self.on_pdata)
        self.pconn.on("close", self.on_pclose)

    def on_pdata(self, conn, address, buffer):
        while buffer:
            data = buffer.next()
            self.conn.write(self.address, data[10:])

    def on_close(self, conn):
        self.pconn.end()
        print(self.conn.address, "closed")

    def on_pclose(self, conn):
        self.conn.end()
        print(self.conn.address, "close")

    def write(self, buffer):
        while buffer:
            data = buffer.next()
            data = "".join(['\x00\x00\x00', struct.pack(">B", 1), socket.inet_aton("8.8.8.8"), struct.pack(">H", 53), data])
            self.pconn.write((sys.argv[2], int(sys.argv[3])), data)

    @staticmethod
    def on_data(server, address, buffer):
        if address not in Request._caches:
            Request._caches[address] = Request(server, address)
            print(address, "connect")

        Request._caches[address].write(buffer)

server = udp.Server()
server.on("data", Request.on_data)
server.bind(("0.0.0.0", int(sys.argv[1])))
loop = current()
loop.start()