fix: Fixes crashing due to bad packet assumptions. (#1829)

### Summary
- Fixes various exploits that can crash the shard when the client misbehaves.
- Clients will now be disconnected if they send packets that are marked as out of game only (new flag), while they are in-game.


> [!Note]
> **Developer Note**
> Added an `OutOfGameOnly` which should be used to flag packets as only available out of the game.
> This is the opposite of, yet not the converse to `InGameOnly`.

Projects/Server/Network/NetState/NetState.cs

@@ -806,20 +806,27 @@ public partial class NetState : IComparable<NetState>, IValueLinkListNode<NetSta
             return ParserState.AwaitingPartialPacket;
         }
 
-        if (handler.Ingame)
+        if (handler.InGameOnly)
         {
             if (Mobile == null)
             {
-                LogInfo($"received packet 0x{packetId:X2} before having been attached to a mobile");
+                LogInfo($"Received packet 0x{packetId:X2} before having been attached to a mobile.");
                 return ParserState.Error;
             }
 
             if (Mobile.Deleted)
             {
+                LogInfo($"Received packet 0x{packetId:X2} after having been attached to a deleted mobile.");
                 return ParserState.Error;
             }
         }
 
+        if (handler.OutOfGameOnly && Mobile?.Deleted == false)
+        {
+            LogInfo($"Received packet 0x{packetId:X2} after having been attached to a mobile.");
+            return ParserState.Error;
+        }
+
         var throttler = handler.ThrottleCallback;
         if (throttler != null)
         {

Projects/Server/Network/PacketHandler.cs

@@ -21,11 +21,20 @@ public unsafe class PacketHandler
 {
     private readonly int _length;
 
-    public PacketHandler(int packetID, int length, bool ingame, delegate*<NetState, SpanReader, void> onReceive)
+    public PacketHandler(
+        int packetID, delegate*<NetState, SpanReader, void> onReceive,
+        int length = 0, bool inGameOnly = false, bool outGameOnly = false
+    ) : this(packetID, length, inGameOnly, outGameOnly, onReceive)
+    {
+
+    }
+
+    public PacketHandler(int packetID, int length, bool inGameOnly, bool outGameOnly, delegate*<NetState, SpanReader, void> onReceive)
     {
         _length = length;
         PacketID = packetID;
-        Ingame = ingame;
+        InGameOnly = inGameOnly;
+        OutOfGameOnly = outGameOnly;
         OnReceive = onReceive;
     }
 
@@ -37,5 +46,7 @@ public unsafe class PacketHandler
 
     public delegate*<int, NetState, bool> ThrottleCallback { get; set; }
 
-    public bool Ingame { get; }
+    public bool InGameOnly { get; }
+
+    public bool OutOfGameOnly { get; }
 }

Projects/Server/Network/Packets/IncomingPackets.cs

@@ -25,9 +25,20 @@ public static class IncomingPackets
     public static PacketHandler[] Handlers { get; } = new PacketHandler[0x100];
 
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
-    public static unsafe void Register(int packetID, int length, bool ingame,
-        delegate*<NetState, SpanReader, void> onReceive) =>
-        Register(new PacketHandler(packetID, length, ingame, onReceive));
+    public static unsafe void Register(
+        int packetID, delegate*<NetState, SpanReader, void> onReceive, int length = 0, bool ingameOnly = false,
+        bool outgameOnly = false
+    ) => Register(packetID, length, ingameOnly, outgameOnly, onReceive);
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static unsafe void Register(
+        int packetID, int length, bool ingame, delegate*<NetState, SpanReader, void> onReceive
+    ) => Register(packetID, length, ingame, false, onReceive);
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static unsafe void Register(
+        int packetID, int length, bool ingame, bool outgame, delegate*<NetState, SpanReader, void> onReceive
+    ) => Register(new PacketHandler(packetID, length, ingame, outgame, onReceive));
 
     public static void Register(PacketHandler packetHandler)
     {