Tons of minor fixes

MistoxServer/Server/ServerConnection.cs

@@ -11,23 +11,24 @@ namespace Mistox.Server {
         public string UserName { get; set; } = "";                          // The Players UserName
         public bool IsAuthenticated { get; set; } = false;                  // Has the player authenticated
         public Vector3 Position { get; set; }                               // The ingame position of the player
-        public DateTime LastHeartbeat { get; set; } = DateTime.UtcNow;      // Connection heartbeat for integrity
         public bool Connected { get; set; } = true;                         // Is the connection valid
         
-        ServerEntity _parent;
-        TcpClient _client;
-        IPEndPoint _remoteAddress;
+        private readonly ServerEntity _parent;
+        private readonly TcpClient _client;
+        private readonly IPEndPoint _remoteAddress;
+        private readonly SemaphoreSlim _sendLock = new SemaphoreSlim(1, 1);
+        private readonly CancellationTokenSource _cts = new();
 
         public ServerConnection( TcpClient tcpClient, ServerEntity parent, IPEndPoint remote ) {
             _parent = parent;
-            _client = tcpClient;
             _remoteAddress = remote;
+            _client = tcpClient;
             _client.NoDelay = true;
+            _client.ReceiveTimeout = _parent.ConnectionTimeoutSeconds * 1000;
 
             ServerInterface.ServerInstance.InvokeUserConnected( this );
             // Start the receive thread
-            Thread receiveThread = new Thread(async () => await ReceiveThread() );
-            receiveThread.Start();
+            Task.Run(ReceiveThread);
         }
 
         async Task ReceiveThread() {
@@ -36,33 +37,26 @@ namespace Mistox.Server {
                     byte[] headerBuffer = new byte[DataPacket.HeaderLength];    
                     byte[] payloadBuffer = new byte[65535];                     // Upper limit for safety
                     while( Connected && _parent.Alive ) {
-
-                        // Tick the last heartbeat or drop
-                        DateTime now = DateTime.UtcNow;
-                        if (LastHeartbeat.AddSeconds(_parent.ConnectionTimeoutSeconds) >= now) {
-                            Connected = false;
-                            Dispose();
-                            break;
-                        }
-                        LastHeartbeat = DateTime.UtcNow;
                         
                         // Read the header off
-                        await ns.ReadExactlyAsync(headerBuffer, 0, 3);
+                        await ns.ReadExactlyAsync(headerBuffer, 0, DataPacket.HeaderLength, _cts.Token);
 
-                        // Parse the header
-                        byte packetbyte = headerBuffer[0];
-                        ushort dataLength = (ushort)((headerBuffer[1] << 8) | headerBuffer[2]);
+                        // Pack the header variables for faster memory passing
+                        DataPacketHeader Header = new DataPacketHeader {
+                            Type = headerBuffer[0],
+                            DataLength = (ushort)((headerBuffer[1] << 8) | headerBuffer[2])
+                        };
 
                         // Make sure the data looks valid
-                        if (dataLength > payloadBuffer.Length) {
+                        if (Header.DataLength > payloadBuffer.Length) {
                             throw new Exception("Incoming TCP payload is too large for the pre-allocated buffer.");
                         }
 
                         // Read off the data
-                        await ns.ReadExactlyAsync(payloadBuffer, 0, dataLength);
+                        await ns.ReadExactlyAsync(payloadBuffer, 0, Header.DataLength, _cts.Token);
 
                         // Create the dataobject
-                        dynamic dataobject = DataPacket.Deserialize( packetbyte, dataLength, payloadBuffer.AsMemory(DataPacket.HeaderLength, dataLength) );
+                        dynamic dataobject = DataPacket.Deserialize( Header, payloadBuffer.AsMemory(DataPacket.HeaderLength) );
 
                         // Return the object
                         _parent.InvokeDataReceived(dataobject);
@@ -71,20 +65,34 @@ namespace Mistox.Server {
                 } catch (Exception e) {
                     _parent.Alive = false;
                     Dispose();
-                    Console.WriteLine("TCP Receive exception: " + e.Message);
+                    Console.WriteLine($"[TCP] Connection lost ({_remoteAddress}): {e.Message}");
+                } finally {
+                    Dispose();
                 }
             }
         }
 
         public async Task Send<T>( T packet ) {
-            byte[] byteData = DataPacket.Serialize( packet );
-            await _client.GetStream().WriteAsync( byteData, 0, byteData.Length );
+            byte[] byteData = DataPacket.Serialize(packet);
+            await _sendLock.WaitAsync();
+            try {
+                await _client.GetStream().WriteAsync(byteData, 0, byteData.Length);
+            } finally {
+                _sendLock.Release();
+            }
         }
 
         public void Dispose() {
+            if (!Connected) return;
+            
             Connected = false;
-            _parent.InvokeUserDisconnected( this );
-            Connected = false;
+            _cts.Cancel();
+            _client.Close();
+            _sendLock.Dispose();
+            _cts.Dispose();
+
+            _parent.Connections.TryRemove(UserName, out _);
+            _parent.InvokeUserDisconnected(this);
             _parent.Alive = false;
             // Remove this item from the Dictionary on the Server for garbage collection
         }