asp.net防类似DDOS攻击(CC攻击)代码
asp.net防类似DDOS攻击(CC攻击)代码
Web.config <httpModules> <!–Url重写–> <add type=”UrlRewriter.RewriterHttpModule, UrlRewriter” name=”UrlRewriter”/> <!–防类似DDOS攻击–> <add type=”UrlRewriter.DDosAttackModule, UrlRewriter” name=”DDosAttackModule”/> </httpModules>using System;using System.Web;using System.Collections.Generic;using System.Collections.Specialized;using System.Timers; namespace UrlRewriter{ /// <summary> /// 阻止攻击IP地址的回应 /// </summary> public class DosAttackModule : IHttpModule { void IHttpModule.Dispose() { } void IHttpModule.Init(HttpApplication context) { context.BeginRequest += new EventHandler(context_BeginRequest); } private static Dictionary<string, short> _IpAdresses = new Dictionary<string, short>(); private static Stack<string> _Banned = new Stack<string>(); private static Timer _Timer = CreateTimer(); private static Timer _BannedTimer = CreateBanningTimer(); private const int BANNED_REQUESTS = 1; //规定时间内访问的最大次数 private const int REDUCTION_INTERVAL = 1000; // 1 秒（检查访问次数的时间段） private const int RELEASE_INTERVAL = 5 * 60 * 1000; // 5 分钟（清除一个禁止IP的时间段） private void context_BeginRequest(object sender, EventArgs e) { string ip = HttpContext.Current.Request.UserHostAddress; if (_Banned.Contains(ip)) { HttpContext.Current.Response.StatusCode = 403; HttpContext.Current.Response.End(); } CheckIpAddress(ip); } /// <summary> /// 检查访问IP /// </summary> private static void CheckIpAddress(string ip) { if (!_IpAdresses.ContainsKey(ip)) //如果没有当前访问IP的记录就将访问次数设为1 { _IpAdresses[ip] = 1; } else if (_IpAdresses[ip] == BANNED_REQUESTS) //如果当前IP访问次数等于规定时间段的最大访问次数就拉于“黑名单” { _Banned.Push(ip); _IpAdresses.Remove(ip); } else //正常访问就加次数 1 { _IpAdresses[ip]++; } } #region Timers /// <summary> /// 创建计时器，从_IpAddress减去一个请求。 /// </summary> private static Timer CreateTimer() { Timer timer = GetTimer(REDUCTION_INTERVAL); timer.Elapsed += new ElapsedEventHandler(TimerElapsed); return timer; } /// <summary> /// 创建定时器，消除一个禁止的IP地址 /// </summary> /// <returns></returns> private static Timer CreateBanningTimer() { Timer timer = GetTimer(RELEASE_INTERVAL); timer.Elapsed += delegate { _Banned.Pop(); }; //消除一个禁止IP return timer; } /// <summary> /// 创建一个时间器，并启动它 /// </summary> /// <param name="interval">以毫秒为单位的时间间隔</param> private static Timer GetTimer(int interval) { Timer timer = new Timer(); timer.Interval = interval; timer.Start(); return timer; } /// <summary> /// 减去从集合中的每个IP地址的请求 /// </summary> private static void TimerElapsed(object sender, ElapsedEventArgs e) { foreach (string key in _IpAdresses.Keys) { _IpAdresses[key]--; if (_IpAdresses[key] == 0) _IpAdresses.Remove(key); } } #endregion }}?