#!/usr/bin/env python
import               subprocess, socket, select, fcntl, sys, os

DEBUG          = os.getenv        ('DEBUG'         ,'1'        )
TUN_MODE       = os.getenv        ('TUN_MODE'      ,'1'        )
PROTOCOL       = os.getenv        ('PROTOCOL'      ,'raw'      )
INTERFACE      = os.getenv        ('ppp-tortun'    ,'1'        )
REMOTE_FLOAT   = int(os.getenv    ('REMOTE_FLOAT'  ,'1'       ))

LOCAL_ADDRESS  = os.getenv        ('LOCAL_ADDRESS' ,'127.0.0.1')
LOCAL_PORT     = int(os.getenv    ('LOCAL_PORT'    ,'2998'    ))

REMOTE_ADDRESS = os.getenv        ('REMOTE_ADDRESS','127.0.0.2')
REMOTE_PORT    = int(os.getenv    ('REMOTE_PORT'   ,'2998'    ))

DST_ADDRESS    = os.getenv        ('DST_ADDRESS'   ,'127.0.0.3')
DST_PORT       = os.getenv        ('DST_PORT'      ,'2998'     )

SOCKS_ADDRESS  = os.getenv        ('LOCAL_ADDRESS' ,'127.0.0.1')
SOCKS_PORT     = os.getenv        ('LOCAL_PORT'    ,'9050'     )

udp            = socket.socket(socket.AF_INET,socket.SOCK_DGRAM)
udp.setsockopt         (socket.SOL_SOCKET,socket.SO_REUSEADDR,1)
udp.setblocking                                              (0)
udp.bind                          ((REMOTE_ADDRESS,REMOTE_PORT))
udp_poll       = select.poll                                  ()
udp_poll.register    (udp.fileno(),select.POLLIN|select.POLLPRI)

if REMOTE_FLOAT==0:
  tun          = subprocess.Popen                             (
                 [ 'socat','stdio','socks4a:'+SOCKS_ADDRESS+':'
                                      +DST_ADDRESS+':'+DST_PORT
                                      +',socksport='+SOCKS_PORT
                 ],
  stdout       = subprocess.PIPE,
  stdin        = subprocess.PIPE,                              )
  tun_stdout   = tun.stdout.fileno                            ()
  tun_stdin    = tun.stdin.fileno                             ()
  tun_poll     = select.poll                                  ()
  tun_poll.register                                           (
               tun.stdout.fileno(),select.POLLIN|select.POLLPRI)

if REMOTE_FLOAT==1:
  tcp            = socket.socket(
                              socket.AF_INET,socket.SOCK_STREAM)
  tcp.setsockopt       (socket.SOL_SOCKET,socket.SO_REUSEADDR,1)
  tcp.setblocking                                            (0)
  tcp.bind                          ((LOCAL_ADDRESS,LOCAL_PORT))
  tcp.listen                                                 (1)
  tcp_poll       = select.poll                                ()
  tcp_poll.register  (tcp.fileno(),select.POLLIN|select.POLLPRI)

  while len(tcp_poll.poll(65536))>0:
    tun        = tcp.accept        ()[0]
    tun_stdout = tun.fileno                                   ()
    tun_stdin  = tun.fileno                                   ()
    tun_poll   = select.poll                                  ()
    tun_poll.register                                         (
                      tun.fileno(),select.POLLIN|select.POLLPRI)
    break

fcntl.fcntl(tun_stdin,fcntl.F_SETFL,fcntl.fcntl(
          tun_stdin,fcntl.F_GETFL)&~os.O_NONBLOCK|os.O_NONBLOCK)
fcntl.fcntl(tun_stdout,fcntl.F_SETFL,fcntl.fcntl(
         tun_stdout,fcntl.F_GETFL)&~os.O_NONBLOCK|os.O_NONBLOCK)

tun            = subprocess.Popen                             (
                              ['/usr/sbin/quicktun.'+PROTOCOL],
stdout         = subprocess.PIPE,
stdin          = subprocess.PIPE,                              )

recvq          = str                                          ()
sendq          = str                                          ()

while 1:
  if len(udp_poll.poll(128))>0:
    buffer     = str                                          ()
    buffer     = udp.recv                                 (1024)
    if len(buffer)==0:
      break
    sendq      = sendq + buffer

  if len(tun_poll.poll(128))>0:
    buffer     = str                                          ()
    buffer     = os.read                       (tun_stdout,1024)
    if len(buffer)==0:
      break
    recvq      = recvq + buffer

  if len(sendq)>0:
    try:
      sendq    = sendq[os.write         (tun_stdin,sendq[:1024])
                 :]
    except OSError as ex:
      if ex.errno!=11:
        break

  if len(recvq)>0:
    try:
      recvq    = recvq[udp.sendto                (recvq[:1024],
                                     (LOCAL_ADDRESS,LOCAL_PORT))
                 :]
    except OSError as ex:
      if ex.errno!=11:
        break

  if len(sendq)>65536*128 or len(recvq)>65536*128:
    break

tun.terminate                                                 ()