Server closes connections gracefully so kick/ban/reset/shutdown messages arrive; status dot and HUD yellow until really connected (also while reconnecting)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

GameServer.cs

@@ -79,7 +79,7 @@ public sealed class GameServer
 
     public void EnqueueCommand(string line) => commands.Enqueue(line);
 
-    int JoinedCount => clients.Values.Count(c => c.State == ClientState.Joined);
+    int JoinedCount => clients.Values.Count(c => c.State == ClientState.Joined && !c.Conn.IsClosing); // gerade getrennte zählen nicht mehr
 
     // ---------------------------------------------------------------- Start / Schleife
 
@@ -142,8 +142,16 @@ public sealed class GameServer
         {
             // Grund mitschicken: die Spieler sehen ihn im Hauptmenü
             if (c.State == ClientState.Joined) c.Conn.Send(MsgType.Reject, Wire.Build(w => w.Write("The server was shut down.")));
-            c.Conn.Close("Server shutting down");
+            c.Conn.CloseAfterSend("Server shutting down");
         }
+        // Kurz warten, bis die Spieler die Meldung gelesen haben (sauber trennen statt hart abbrechen)
+        var waitUntil = DateTime.UtcNow.AddSeconds(1.5);
+        while (DateTime.UtcNow < waitUntil && clients.Values.Any(c => !c.Conn.IsClosed))
+        {
+            foreach (var c in clients.Values) c.Conn.Poll();
+            Thread.Sleep(20);
+        }
+        foreach (var c in clients.Values) c.Conn.Close("Server shutting down");
         listener.Stop();
         SaveWorld();
         if (!offline)
@@ -272,7 +280,7 @@ public sealed class GameServer
                     w.Write(names.Count);
                     foreach (string n in names) w.Write(n);
                 }));
-                c.Conn.Close("Info query");
+                c.Conn.CloseAfterSend("Info query");
                 return;
 
             case MsgType.Hello:
@@ -404,8 +412,8 @@ public sealed class GameServer
         c.SteamVerified = steam.Enabled && !c.SteamId.StartsWith("name:");
         foreach (var other in clients.Values)
         {
-            if (other == c || other.State != ClientState.Joined || other.SteamId != c.SteamId) continue;
-            if (c.SteamVerified) other.Conn.Close("Joined from another location"); // echter Account: alte Verbindung trennen
+            if (other == c || other.State != ClientState.Joined || other.Conn.IsClosing || other.SteamId != c.SteamId) continue;
+            if (c.SteamVerified) other.Conn.CloseAfterSend("Joined from another location"); // echter Account: alte Verbindung trennen
             else { Reject(c, "A player with this identity is already connected"); return; }
         }
 
@@ -440,7 +448,7 @@ public sealed class GameServer
     void Reject(Client c, string reason)
     {
         c.Conn.Send(MsgType.Reject, Wire.Build(w => w.Write(reason)));
-        c.Conn.Close(reason);
+        c.Conn.CloseAfterSend(reason);
         Log($"Rejected {c.Name} ({c.Conn.RemoteAddress}): {reason}");
     }
 
@@ -472,7 +480,7 @@ public sealed class GameServer
         foreach (var c in clients.Values.Where(x => x.State == ClientState.Joined).ToList())
         {
             c.Conn.Send(MsgType.Reconnect, Wire.Build(w => w.Write(message)));
-            c.Conn.Close("Reconnect after world change");
+            c.Conn.CloseAfterSend("Reconnect after world change");
             count++;
         }
         if (count > 0) Log($"{count} player(s) will reconnect");

Protocol.cs

@@ -89,6 +89,9 @@ public sealed class Connection
 
     readonly TcpClient client;
     readonly NetworkStream stream;
+    bool closing;            // Meldung gesendet, warten bis der Spieler sie gelesen hat (siehe CloseAfterSend)
+    DateTime closeDeadline;
+    string closingReason;
     readonly byte[] readBuffer = new byte[64 * 1024];
     byte[] buffer = new byte[64 * 1024];
     int count;
@@ -106,6 +109,11 @@ public sealed class Connection
     {
         var messages = new List<Message>();
         if (IsClosed) return messages;
+        if (closing)
+        {
+            DrainWhileClosing();
+            return messages;
+        }
         try
         {
             if (client.Client.Poll(0, SelectMode.SelectRead) && client.Available == 0)
@@ -131,7 +139,7 @@ public sealed class Connection
 
     public void Send(MsgType type, byte[] payload = null)
     {
-        if (IsClosed) return;
+        if (IsClosed || closing) return;
         try
         {
             byte[] frame = Wire.Frame(type, payload);
@@ -143,6 +151,38 @@ public sealed class Connection
         }
     }
 
+    /// <summary>
+    /// Sauber trennen, nachdem eine letzte Meldung gesendet wurde (Kick/Ban-Grund, Neu-Verbinden, Shutdown).
+    /// Sofortiges Close() mit noch ungelesenen Daten des Spielers (er schickt ständig Positionen) führt zu einem
+    /// TCP-Reset - dann geht die gerade gesendete Meldung verloren. Deshalb: nur die Sende-Richtung schließen,
+    /// eingehende Daten noch kurz lesen und verwerfen, dann erst schließen.
+    /// </summary>
+    public void CloseAfterSend(string reason)
+    {
+        if (IsClosed || closing) return;
+        closing = true;
+        closingReason = reason;
+        closeDeadline = DateTime.UtcNow.AddSeconds(3);
+        try { client.Client.Shutdown(SocketShutdown.Send); } catch { Close(reason); }
+    }
+
+    public bool IsClosing => closing && !IsClosed;
+
+    void DrainWhileClosing()
+    {
+        try
+        {
+            while (stream.DataAvailable)
+                if (stream.Read(readBuffer, 0, readBuffer.Length) <= 0) break;
+            bool remoteClosed = client.Client.Poll(0, SelectMode.SelectRead) && client.Available == 0;
+            if (remoteClosed || DateTime.UtcNow >= closeDeadline) Close(closingReason);
+        }
+        catch
+        {
+            Close(closingReason);
+        }
+    }
+
     public void Close(string reason)
     {
         if (IsClosed) return;

Tests/Program.cs

@@ -155,6 +155,20 @@ try
     watcher.Close();
     await Task.Delay(300);
 
+    Console.WriteLine("== Kick reason arrives while the player keeps sending");
+    var spammer = await TestClient.Join("Spammer", 0, null);
+    var spamming = true;
+    var spamTask = Task.Run(async () => { while (spamming) { spammer.Send(MsgType.Player, PlayerPos(1f, 2f, 3f)); await Task.Delay(5); } });
+    await Task.Delay(300);
+    server.EnqueueCommand("kick " + spammer.Id + " testing");
+    var kickMsg = await spammer.WaitFor(MsgType.Reject, 3000);
+    spamming = false;
+    await spamTask;
+    Check(kickMsg != null && new BinaryReader(new MemoryStream(kickMsg)).ReadString().Contains("testing"),
+          "Kicked player receives the reason even while sending data (no hard reset)");
+    spammer.Close();
+    await Task.Delay(300);
+
     Console.WriteLine("== reset-world makes everyone reconnect");
     var r1 = await TestClient.Join("Resetter", 0, null);
     server.EnqueueCommand("reset-world");