Reorganizes Project (#41)

Projects/Scripts/Accounting/AccountAttackLimiter.cs

@@ -0,0 +1,131 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Net;
+using Server.Network;
+
+namespace Server.Accounting
+{
+  public class AccountAttackLimiter
+  {
+    public static bool Enabled = true;
+
+    private static List<InvalidAccountAccessLog> m_List = new List<InvalidAccountAccessLog>();
+
+    public static void Initialize()
+    {
+      if (!Enabled)
+        return;
+
+      PacketHandlers.RegisterThrottler(0x80, Throttle_Callback);
+      PacketHandlers.RegisterThrottler(0x91, Throttle_Callback);
+      PacketHandlers.RegisterThrottler(0xCF, Throttle_Callback);
+    }
+
+    public static TimeSpan Throttle_Callback(NetState ns)
+    {
+      InvalidAccountAccessLog accessLog = FindAccessLog(ns);
+
+      if (accessLog == null)
+        return TimeSpan.Zero;
+
+      DateTime date = DateTime.UtcNow;
+      DateTime access = accessLog.LastAccessTime + ComputeThrottle(accessLog.Counts);
+      return date >= access ? TimeSpan.Zero : date - access;
+    }
+
+    public static InvalidAccountAccessLog FindAccessLog(NetState ns)
+    {
+      if (ns == null)
+        return null;
+
+      IPAddress ipAddress = ns.Address;
+
+      for (int i = 0; i < m_List.Count; ++i)
+      {
+        InvalidAccountAccessLog accessLog = m_List[i];
+
+        if (accessLog.HasExpired)
+          m_List.RemoveAt(i--);
+        else if (accessLog.Address.Equals(ipAddress))
+          return accessLog;
+      }
+
+      return null;
+    }
+
+    public static void RegisterInvalidAccess(NetState ns)
+    {
+      if (ns == null || !Enabled)
+        return;
+
+      InvalidAccountAccessLog accessLog = FindAccessLog(ns);
+
+      if (accessLog == null)
+        m_List.Add(accessLog = new InvalidAccountAccessLog(ns.Address));
+
+      accessLog.Counts += 1;
+      accessLog.RefreshAccessTime();
+
+      if (accessLog.Counts >= 3)
+        try
+        {
+          using (StreamWriter op = new StreamWriter("throttle.log", true))
+          {
+            op.WriteLine(
+              "{0}\t{1}\t{2}",
+              DateTime.UtcNow,
+              ns,
+              accessLog.Counts
+            );
+          }
+        }
+        catch
+        {
+          // ignored
+        }
+    }
+
+    public static TimeSpan ComputeThrottle(int counts)
+    {
+      if (counts >= 15)
+        return TimeSpan.FromMinutes(5.0);
+
+      if (counts >= 10)
+        return TimeSpan.FromMinutes(1.0);
+
+      if (counts >= 5)
+        return TimeSpan.FromSeconds(20.0);
+
+      if (counts >= 3)
+        return TimeSpan.FromSeconds(10.0);
+
+      if (counts >= 1)
+        return TimeSpan.FromSeconds(2.0);
+
+      return TimeSpan.Zero;
+    }
+  }
+
+  public class InvalidAccountAccessLog
+  {
+    public InvalidAccountAccessLog(IPAddress address)
+    {
+      Address = address;
+      RefreshAccessTime();
+    }
+
+    public IPAddress Address{ get; set; }
+
+    public DateTime LastAccessTime{ get; set; }
+
+    public bool HasExpired => DateTime.UtcNow >= LastAccessTime + TimeSpan.FromHours(1.0);
+
+    public int Counts{ get; set; }
+
+    public void RefreshAccessTime()
+    {
+      LastAccessTime = DateTime.UtcNow;
+    }
+  }
+}