using?Protocol.DomainNameSystem;
using?Protocol.DomainNameSystem.Simple;
using?System;
using?System.Collections.Generic;
using?System.Text;
using?System.Threading;

namespace?ConsoleApplication1
{
????class?Program
????{

????????static?DnsPacket?MyProcess（DnsPacket?request）
????????{
????????????if?（request._3_4_OPCODE?!=?DnsPacket.OPCODE_QUERY）
????????????{
????????????????return?null;
????????????}

????????????for?（int?i?=?0;?i?????????????{
????????????????if?（request.QDList[i]._2_2_TYPE?==?DnsPacket.TYPE_A?&&?request.QDList[i]._3_2_CLASS?==?DnsPacket.CLASS_IN?&&
????????????????????request.QDList[i].ResolveName（request）.ToLower（）.EndsWith（“.user.adsl001.com“））
????????????????{
????????????????????/*
?????????????????????*?根據(jù)域名查找IP。
?????????????????????*/
????????????????????string?domian?=?request.QDList[i].ResolveName（request）;
????????????????????UInt32?ttl?=?10;????//?域名對(duì)應(yīng)的IP失效時(shí)間，單位為秒，超過此時(shí)間后客戶端應(yīng)該重新發(fā)起查詢。
????????????????????string?ip?=?“192.168.0.25“;?//?IP等會(huì)填到這里
????????????????????//?你來寫這一段，通過域名查找IP，從緩存里面去讀，沒有時(shí)間給你查數(shù)據(jù)庫的。

????????????????????/*
?????????????????????*?生成應(yīng)答數(shù)據(jù)包。
?????????????????????*/
????????????????????DnsPacket?response?=?new?DnsPacket（）;
????????????????????response._1_16_ID?=?request._1_16_ID;
????????????????????response._2_1_QR?=?DnsPacket.QR_REPLY;
????????????????????response._3_4_OPCODE?=?DnsPacket.OPCODE_QUERY;
????????????????????response._4_1_AA?=?DnsPacket.AA_NON_AUTHORITATIVE_ANSWER;
????????????????????response._5_1_TC?=?DnsPacket.TC_NON_TRUNCATION;
????????????????????response._6_1_RD?=?DnsPacket.RD_NON_RECURSION_DESIRED;
????????????????????response._7_1_RA?=?DnsPacket.RA_NON_RECURSION_AVAILABLE;
????????????????????response._8_3_Z?=?0;
????????????????????response._9_4_RCODE?=?DnsPacket.RCODE_NO_ERROR;

????????????????????DnsQuestion?question?=?new?DnsQuestion（）;
????????????????????question._1_N_NAME?=?request.ResolveNameBytes（request.QDList[i]._1_N_NAME）;
????????????????????question._2_2_TYPE?=?request.QDList[i]._2_2_TYPE;
????????????????????question._3_2_CLASS?=?request.QDList[i]._3_2_CLASS;

????????????????????response.QDList.Add（question）;
????????????????????response._10_16_QDCOUNT?=?（UInt16）response.QDList.Count;

????????????????????DnsResourceRecord?record?=?new?DnsResourceRecord（）;
????????????????????record._1_N_NAME?=?request.ResolveNameBytes（request.QDList[i]._1_N_NAME）;
????????????????????record._2_2_TYPE?=?DnsPacket.TYPE_A;
????????????????????record._3_2_CLASS?=?DnsPacket.CLASS_IN;
????????????????????record._4_4_TTL?=?ttl;
????????????????????record._6_N_RDDATA?=?DnsHelper.FromIPString（ip）;
????????????????????record._5_2_RDLENGTH?=?（UInt16）record._6_N_RDDATA.Length;

????????????????????response.ANList.Add（record）;
????????????????????response._11_16_ANCOUNT?=?（UInt16）response.ANList.Count;
????????????????????
????????????????????return?response;
????????????????}
????????????}

??