fix(network): Adds UOG & Fixes ConnectUO packet (#552)

- [X] Adds UOG Extended and Compact (0xF1 0x51 packet)
- [X] Fixes ConnectUO bad length

Projects/UOContent/Network/ConnectUO.cs

@@ -109,7 +109,7 @@ namespace Server.Network
 
             var writer = new SpanWriter(stackalloc byte[15]);
             writer.Write((byte)0xC0); // Packet ID
-            writer.Write(17); // Length
+            writer.Write((ushort)17); // Length
             writer.Write(ConnectUOProtocolVersion); // Version
             writer.Write((byte)_serverType);
             writer.Write((int)(Core.TickCount / 1000));

Projects/UOContent/Network/UOGateway.cs

@@ -0,0 +1,103 @@
+/*************************************************************************
+ * ModernUO                                                              *
+ * Copyright (C) 2019-2021 - ModernUO Development Team                   *
+ * Email: hi@modernuo.com                                                *
+ * File: UOGateway.cs                                                    *
+ *                                                                       *
+ * This program is free software: you can redistribute it and/or modify  *
+ * it under the terms of the GNU General Public License as published by  *
+ * the Free Software Foundation, either version 3 of the License, or     *
+ * (at your option) any later version.                                   *
+ *                                                                       *
+ * You should have received a copy of the GNU General Public License     *
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>. *
+ *************************************************************************/
+
+using System;
+using System.Buffers;
+using System.Text;
+using Server.Misc;
+using Server.Text;
+
+namespace Server.Network
+{
+    public static class UOGateway
+    {
+        public static void Configure()
+        {
+            var enabled = ServerConfiguration.GetOrUpdateSetting("uogateway.enabled", true);
+
+            if (enabled)
+            {
+                FreeshardProtocol.Register(0xFE, false, QueryCompactShardStats);
+                FreeshardProtocol.Register(0xFF, false, QueryExtendedShardStats);
+            }
+        }
+
+        public static void QueryCompactShardStats(NetState ns, CircularBufferReader reader, ref int packetLength)
+        {
+            ns.SendCompactShardStats(
+                (uint)(Core.TickCount / 1000),
+                TcpServer.Instances.Count,
+                World.Items.Count,
+                World.Mobiles.Count,
+                GC.GetTotalMemory(false)
+            );
+        }
+
+        public static void QueryExtendedShardStats(NetState ns, CircularBufferReader reader, ref int packetLength)
+        {
+            const long ticksInHour = 1000 * 60 * 60;
+            ns.SendExtendedShardStats(
+                ServerList.ServerName,
+                (int)(Core.TickCount / ticksInHour),
+                TcpServer.Instances.Count,
+                World.Items.Count,
+                World.Mobiles.Count,
+                (int)(GC.GetTotalMemory(false) / 1024)
+            );
+        }
+
+        public static void SendCompactShardStats(
+            this NetState ns, uint age, int clients, int items, int mobiles, long mem
+        )
+        {
+            if (ns == null)
+            {
+                return;
+            }
+
+            var writer = new SpanWriter(stackalloc byte[27]);
+            writer.Write((byte)0x51); // Packet ID
+            writer.Write((ushort)27); // Length
+            writer.Write(clients);
+            writer.Write(items);
+            writer.Write(mobiles);
+            writer.Write(age);
+            writer.Write(mem);
+
+            ns.Send(writer.Span);
+        }
+
+        public static void SendExtendedShardStats(
+            this NetState ns, string name, int age, int clients, int items, int mobiles, int mem
+        )
+        {
+            if (ns == null)
+            {
+                return;
+            }
+
+            var str =
+                $"ModernUO, Name={name}, Age={age}, Clients={clients}, Items={items}, Chars={mobiles}, Mem={mem}, Ver=2";
+
+            var length = Encoding.UTF8.GetMaxByteCount(str.Length);
+
+            Span<byte> span = stackalloc byte[length + 1];
+            Encoding.UTF8.GetBytes(str, span);
+            span[^1] = 0; // Terminator
+
+            ns.Send(span);
+        }
+    }
+}