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

def exit(sn,sf):
  try:
    tun.terminate                                             ()
  except:
    pass
signal.signal                              (signal.SIGHUP, exit)
signal.signal                              (signal.SIGINT, exit)
signal.signal                              (signal.SIGTERM,exit)

DEBUG          = os.getenv        ('DEBUG'         ,'1'        )
TUN_MODE       = os.getenv        ('TUN_MODE'      ,'1'        )
PROTOCOL       = os.getenv        ('PROTOCOL'      ,'raw'      )
INTERFACE      = os.getenv        ('INTERFACE'     ,'ppp-socks')
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        ('SOCKS_ADDRESS' ,'127.0.0.1')
SOCKS_PORT     = os.getenv        ('SOCKS_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:
  os.environ.pop                                ('REMOTE_FLOAT')
  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:
  tun          = subprocess.Popen                             (
                       ['socat','TCP-LISTEN:'+str(LOCAL_PORT)
                        +',BIND='+LOCAL_ADDRESS+',REUSEADDR',
                        'UDP-CONNECT:'+LOCAL_ADDRESS+':'+str(
                                                  LOCAL_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)

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)

time.sleep                                                   (4)

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                                                 ()