#!/usr/bin/env python

# Copyright (c) 2012 clowwindy
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

import sys
import socket
import struct
import string
import hashlib
import os
import json
import logging
import getopt

from tornado import ioloop
from tornado import iostream
from tornado import netutil


class Crypto(object):
    def __init__(self, password):
        m = hashlib.md5()
        m.update(password)
        s = m.digest()
        a, b = struct.unpack('<QQ', s)
        trans = string.maketrans('', '')
        table = list(trans)
        for i in xrange(1, 1024):
            table.sort(lambda x, y: int(a % (ord(x) + i) - a % (ord(y) + i)))
        self._encrypt_table = ''.join(table)
        self._decrypt_table = string.maketrans(self._encrypt_table, trans)

    def encrypt(self, data):
        return data.translate(self._encrypt_table)

    def decrypt(self, data):
        return data.translate(self._decrypt_table)


class Socks5Server(netutil.TCPServer):
    def handle_stream(self, stream, address):
        soc = stream.socket
        soc.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, True)
        ConnHandler(soc).wait_for_data()


class PairedStream(iostream.IOStream):
    def on_close(self):
        remote = getattr(self, "remote")
        if isinstance(remote, PairedStream) and not remote.closed():
            if remote.writing():
                remote.write("", callback=remote.close())
            else:
                remote.close()


class ConnHandler(PairedStream):
    def wait_for_data(self):
        self.read_bytes(1, self.on_addrtype)

    def on_addrtype(self, addrtype):
        addrtype = ord(crypto.decrypt(addrtype))
        if addrtype == 1:
            self.read_bytes(4, self.on_addr1)
        elif addrtype == 3:
            self.read_bytes(1, self.on_addr3_length)
        else:
            # not support
            logging.warn('addr_type not support')
            self.close()

    def on_addr1(self, addr):
        self.remote_addr = socket.inet_ntoa(crypto.decrypt(addr))
        self.read_bytes(2, self.on_port)

    def on_addr3_length(self, length):
        length = ord(crypto.decrypt(length))
        self.read_bytes(length, self.on_addr3)

    def on_addr3(self, addr):
        self.remote_addr = crypto.decrypt(addr)
        self.read_bytes(2, self.on_port)

    def on_port(self, port):
        self.remote_port = struct.unpack('>H', crypto.decrypt(port))[0]
        logging.debug("Connecting to %s:%d" % (self.remote_addr, self.remote_port))
        remote_soc = socket.socket()
        remote_soc.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, True)
        self.remote = PairedStream(remote_soc)
        self.set_close_callback(self.remote.on_close)
        self.remote.set_close_callback(self.on_close)

        self.remote.connect((self.remote_addr, self.remote_port), self.on_remote_connected)

    def on_remote_connected(self):
        self.read_until_close(callback=self.on_client_read, streaming_callback=self.on_client_read)
        self.remote.read_until_close(callback=self.on_remote_read, streaming_callback=self.on_remote_read)

    def on_client_read(self, data):
        self.remote.write(crypto.encrypt(data))

    def on_remote_read(self, data):
        self.write(crypto.decrypt(data))


if __name__ == "__main__":
    logging.basicConfig(level=logging.DEBUG, format='%(asctime)s %(levelname)-8s %(message)s',
                        datefmt='%Y-%m-%d %H:%M:%S', filemode='a+')
    with open(os.path.join(os.path.dirname(__file__), "config.json"), "rb") as f:
        config = json.load(f)

    server_port = config['server_port']
    server_password = config['password']

    optlist, args = getopt.getopt(sys.argv[1:], 'p:k:')
    for key, value in optlist:
        if key == '-p':
            server_port = int(value)
        elif key == '-k':
            server_password = value

    if '-6' in sys.argv[1:]:
        address_family = socket.AF_INET6
    else:
        address_family = socket.AF_INET

    crypto = Crypto(server_password)

    logging.info("starting server at port %d ..." % server_port)
    server = Socks5Server()
    server.bind(port=server_port, family=address_family)
    server.start()
    try:
        ioloop.IOLoop.instance().start()
    except KeyboardInterrupt:
        pass
    except Exception:
        logging.exception("Uncaught Exception")