using System;using System.Collections;using System.Collections.Generic;using System.Text;using System.Net;using System.Net.Sockets;using System.Threading;using System.Xml;using System.IO;namespace App.Core{ /// <summary> /// DNS服务器 /// 运行程序,把网络协议中的DNS改为127.0.0.1,如果ping www.csdn.net,如果给出的地址是127.0.0.1,说明有效果 /// 目前只处理 A 类型的请求,其他一律转发给公共DNS服务器. /// </summary> public class DnsServer { protected System.Threading.Thread ListenThread = null; private Socket ServerSocket; public Hashtable IntranetMaps = new Hashtable(); public Hashtable ExtranetMaps = new Hashtable(); public IPEndPoint Forwarder; public DnsServer() { } public void LoadConfig() { try { if (!File.Exists(Fun.GetAppPath() "\\Config.xml")) { CreateConfigFile(); } Xml xml = new Xml(Fun.GetAppPath() "\\Config.xml"); string debug = xml.GetText("//config/debug").ToLower(); if (debug == "true" || debug == "1") { Fun.DebugFlag = true; } // Forwarder当自己不知道的域名时转交给Forwarder处理 string forwarderIP = xml.GetText("//config/forwarder").Trim(); if (forwarderIP == "") { forwarderIP = "60.191.244.5"; } this.Forwarder = new IPEndPoint(IPAddress.Parse(forwarderIP), 53);//公共DNS服务器IP // 内网 this.IntranetMaps.Clear(); XmlNodeList xmlIntranetMaps = xml.GetNodes("//intranet/map"); foreach (XmlNode xmlIntranetMap in xmlIntranetMaps) { string domain = xml.GetAttribute(xmlIntranetMap, "domain".Trim()); string ip = xml.GetAttribute(xmlIntranetMap, "ip").Trim(); IntranetMaps[domain] = ip; } // 外网 this.ExtranetMaps.Clear(); XmlNodeList xmlExtranetMaps = xml.GetNodes("//extranet/map"); foreach (XmlNode xmlExtranetMap in xmlExtranetMaps) { string domain = xml.GetAttribute(xmlExtranetMap, "domain").Trim(); string ip = xml.GetAttribute(xmlExtranetMap, "ip").Trim(); ExtranetMaps[domain] = ip; } } catch (Exception ex) { Fun.Log(ex.Message); } } /// <summary> /// 当用udp.Send给某个不存在的节点(对方开端口)发送过数据，再调用udp.Receive就会跳出SocketException:远程主机强迫关闭了一个现有的连接 /// 这是Socket的一个Bug /// </summary> public void FixUdpConnectionResetBug(Socket socket) { uint IOC_IN = 0x80000000; uint IOC_VENDOR = 0x18000000; uint SIO_UDP_CONNRESET = IOC_IN | IOC_VENDOR | 12; socket.IOControl((int)SIO_UDP_CONNRESET, new byte[] { Convert.ToByte(false) }, null); } public void RunThread() { // 线程 this.ListenThread = new System.Threading.Thread(new ThreadStart(this.ListenThreadFunction)); this.ListenThread.Start(); } public void ListenThreadFunction() { LoadConfig(); try { this.ServerSocket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp); FixUdpConnectionResetBug(this.ServerSocket); this.ServerSocket.Bind(new IPEndPoint(IPAddress.Any, 53)); Fun.LogDebug("DnsServer Start"); } catch (Exception ex) { Fun.Log(ex.Message); return; } while (true) { try { DnsServerThread clientThread = new DnsServerThread(this); EndPoint client = (EndPoint)new IPEndPoint(IPAddress.Any, 0); clientThread.BufferLength = this.ServerSocket.ReceiveFrom(clientThread.Buffer, ref client); clientThread.Client = (IPEndPoint)client; clientThread.RunThread(); } catch (Exception ex) { Fun.Log("DnsServer Error:" ex.Message); } } } // 因为多线程都要发，所以要同步 public void SendToClient(byte[] bytes, EndPoint client) { lock (typeof(DnsServer)) { this.ServerSocket.SendTo(bytes, client); } } // 自动创建配置文件 public static void CreateConfigFile() { if (File.Exists(Fun.GetAppPath() "\\Config.xml")) { return; } StringBuilder sb = new StringBuilder(); sb.Append("<?xml version=\"1.0\" encoding=\"utf-8\"?>\r\n"); sb.Append("<config>\r\n"); sb.Append(" <debug>false</debug>\r\n"); sb.Append(" <forwarder>60.191.244.5</forwarder>\r\n"); sb.Append(" <heartbeaturl>http://heartbeat.ywu.cn/HeartBeat.aspx?System=Dns</heartbeaturl>\r\n"); sb.Append(" <intranet>\r\n"); sb.Append(" <map domain=\"www.goodluck.com\" ip=\"172.16.1.1\"/>\r\n"); sb.Append(" </intranet>\r\n"); sb.Append(" <extranet>\r\n"); sb.Append(" <map domain=\"www.goodluck.com\" ip=\"60.191.227.188\"/>\r\n"); sb.Append(" </extranet>\r\n"); sb.Append("</config>\r\n"); File.WriteAllText(Fun.GetAppPath() "\\Config.xml", sb.ToString()); } }}
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