# -*- coding: utf-8 -*-
# tcp mapping created by hutaow(hutaow.com) at 2014-08-31

import socket
import threading

# 端口映射配置信息
CFG_REMOTE_IP = '192.168.0.10'
CFG_REMOTE_PORT = 22
CFG_LOCAL_IP = '0.0.0.0'
CFG_LOCAL_PORT = 10022

# 接收数据缓存大小
PKT_BUFF_SIZE = 2048

# 调试日志封装
def send_log(content):
  print content
  return

# 单向流数据传递
def tcp_mapping_worker(conn_receiver, conn_sender):
  while True:
    try:
      data = conn_receiver.recv(PKT_BUFF_SIZE)
    except Exception:
      send_log('Event: Connection closed.')
      break

    if not data:
      send_log('Info: No more data is received.')
      break

    try:
      conn_sender.sendall(data)
    except Exception:
      send_log('Error: Failed sending data.')
      break

    # send_log('Info: Mapping data > %s ' % repr(data))
    send_log('Info: Mapping > %s -> %s > %d bytes.' % (conn_receiver.getpeername(), conn_sender.getpeername(), len(data)))

  conn_receiver.close()
  conn_sender.close()

  return

# 端口映射请求处理
def tcp_mapping_request(local_conn, remote_ip, remote_port):
  remote_conn = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

  try:
    remote_conn.connect((remote_ip, remote_port))
  except Exception:
    local_conn.close()
    send_log('Error: Unable to connect to the remote server.')
    return

  threading.Thread(target=tcp_mapping_worker, args=(local_conn, remote_conn)).start()
  threading.Thread(target=tcp_mapping_worker, args=(remote_conn, local_conn)).start()

  return

# 端口映射函数
def tcp_mapping(remote_ip, remote_port, local_ip, local_port):
  local_server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
  local_server.bind((local_ip, local_port))
  local_server.listen(5)

  send_log('Event: Starting mapping service on ' + local_ip + ':' + str(local_port) + ' ...')

  while True:
    try:
      (local_conn, local_addr) = local_server.accept()
    except KeyboardInterrupt, Exception:
      local_server.close()
      send_log('Event: Stop mapping service.')
      break

    threading.Thread(target=tcp_mapping_request, args=(local_conn, remote_ip, remote_port)).start()

    send_log('Event: Receive mapping request from %s:%d.' % local_addr)

  return

# 主函数
if __name__ == '__main__':
  tcp_mapping(CFG_REMOTE_IP, CFG_REMOTE_PORT, CFG_LOCAL_IP, CFG_LOCAL_PORT)