C#端口扫描

using system;
using system.drawing;
using system.collections;
using system.componentmodel;
using system.windows.forms;
//增加的如下..
using system.data;
using system.net.sockets;
using system.net;
using system.io;
using system.text;
using system.threading;

namespace iportscan
{
 /// <summary>
 /// summary description for form1.
 /// </summary>
 public class form1 : system.windows.forms.form
 {
  //该处放的是程序要用到的公共变量
  public string scanhost = dns.gethostname(); //默认当前本机ip
  public int32 tport = 0; //当前连接端口编号
  public int32 connstate = 0; //扫描状态
  public int portsum = 0 ; //端口总计
  public bool endthread = false; //结束状态
  public autoresetevent asyncopsaredone = new autoresetevent(false);
  private system.windows.forms.label label1 = new label();
  private system.windows.forms.textbox txthostname;
  private system.windows.forms.button cmdexec;
  private system.windows.forms.listbox loglist;
  public system.windows.forms.checkedlistbox portlist;
  private system.windows.forms.label label2;
  private system.windows.forms.label label3;
  private system.windows.forms.numericupdown snum;
  private system.windows.forms.numericupdown enum;
  private system.windows.forms.checkbox showdie;
  private system.windows.forms.label label4;
  private system.windows.forms.button button1;
  private system.windows.forms.tooltip tooltip1;
  private system.windows.forms.statusbar statusbar1;
  private system.windows.forms.linklabel linklabel1;
  private system.windows.forms.linklabel linklabel2;
  private system.componentmodel.icontainer components;
  /*
  此处省略了各个调用的控件的属性设置代码
  */
  static void main()
  {
   application.run(new form1());
  }

  private void cmdexec_click(object sender, system.eventargs e)
  {
   int32 startport = (int32)snum.value;
   int32 endport = (int32)enum.value;
   if(txthostname.text.length==0)
   {
    messagebox.show("请输入一个主机的名称吧！","系统提示");
    txthostname.text = scanhost.tostring();
    txthostname.focus();
    return;
   }
   if(startport>endport)
   {
    messagebox.show("错误，起始端口必须要小于结束的端口!","系统提示");
    startport = endport-1;
    snum.text = startport.tostring();
    snum.focus();
    return ;
   }

   if(cmdexec.text=="&scan")
   {
    endthread= false;
    cmdexec.text= "&stop";
   }
   else
   {
    endthread= true;
    cmdexec.text= "&scan";
   }

   if(endthread!=true)
   {
    connstate = 0;
    portsum = 0;
    scanhost = txthostname.text;
    try
    {
     ipaddress ipaddr =(ipaddress)dns.resolve(scanhost).addresslist.getvalue(0);
     txthostname.text = ipaddr.tostring();
    }
    catch
    {
     txthostname.focus();
     messagebox.show("请输入正确的主机地址,该地址dns无法解析","系统提示");
     return ;
    }
    loglist.items.clear();

    for (int32 threadnum = startport; threadnum <=endport; threadnum++)
    {
     threadpool.queueuserworkitem(new waitcallback(startscan),threadnum);
     loglist.items.add ("扫描端口:" + threadnum.tostring());
    }

   }
  }
  public void startscan(object state)
  {
   int32 port = (int32) state;
   string tmsg = "";
   string getdata = "";
   int lindex = 0;
   int eindex = 0;
   connstate++; //判断线程数目
   if(endthread==true)
   {
    if(connstate==((int32)enum.value-(int32)snum.value))
    {
     cmdexec.text = "&scan";
     loglist.items.add ("扫描完毕!");
    }
    else
    {
     cmdexec.text = "&stop";
     loglist.items.add ("正在停止对"+port.tostring()+"端口的扫描线程");
    }
    loglist.items.add("结束线程:"+port.tostring());
    asyncopsaredone.close();
   }
   else
   {
    try
    {
     tcpclient tcp = new tcpclient();
     tcp.connect(scanhost,port);
     //该处如果建立连接错误的话，将不执行下面的代码..
     portsum ++;
     lindex = portlist.items.add(port.tostring() + "端口开放",false);
     portlist.selectedindex=lindex;
     stream sm = tcp.getstream();
     sm.write(encoding.default.getbytes(tmsg.tochararray()),0,tmsg.length);
     streamreader sr = new streamreader(tcp.getstream(),encoding.default);
     getdata = sr.readline();
     if(lindex!=0&&getdata.length!=0)
     {
      tmsg = " +-" + port.tostring() + "端口数据:"+getdata.tostring();
      eindex = portlist.items.add(tmsg); //插入一条信息记录
      portlist.items.insert(lindex+1,tmsg);
      portlist.items.removeat(eindex);
     }
     sr.close();
     sm.close();
     tcp.close();
    }
    catch
    {
     //显示坏死的端口
     if(showdie.checked==true)
     {
      portlist.items.add(port.tostring()+"端口无法连接,回传数据为空");
     }
    }
    finally
    {
     thread.sleep(0);
     loglist.items.add("结束线程:"+port.tostring());
     asyncopsaredone.close();
     statusbar1.text = "端口总计:"+portsum.tostring() ;
     if(connstate==((int32)enum.value-(int32)snum.value))
     {
      cmdexec.text = "&scan";
     }
    }
   }
  }

  private void button1_click(object sender, system.eventargs e)
  {
   application.exit();
  }

 }
}