From f5ade69f6de41859d041cd01e6283c5427847be1 Mon Sep 17 00:00:00 2001
From: Pieter-Jan Briers <pieterjan.briers+git@gmail.com>
Date: Fri, 22 Mar 2024 00:18:38 +0100
Subject: [PATCH] Show MTU in network debug panel.

---
 .../CustomControls/DebugMonitorControls/DebugNetPanel.cs  | 2 +-
 Robust.Shared/Network/INetChannel.cs                      | 8 +++++++-
 Robust.Shared/Network/NetManager.NetChannel.cs            | 2 ++
 Robust.UnitTesting/RobustIntegrationTest.NetManager.cs    | 1 +
 4 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/Robust.Client/UserInterface/CustomControls/DebugMonitorControls/DebugNetPanel.cs b/Robust.Client/UserInterface/CustomControls/DebugMonitorControls/DebugNetPanel.cs
index ce06806b46..70a6de84e2 100644
--- a/Robust.Client/UserInterface/CustomControls/DebugMonitorControls/DebugNetPanel.cs
+++ b/Robust.Client/UserInterface/CustomControls/DebugMonitorControls/DebugNetPanel.cs
@@ -90,7 +90,7 @@ namespace Robust.Client.UserInterface.CustomControls.DebugMonitorControls
             contents.TextMemory = FormatHelpers.FormatIntoMem(_textBuffer,
                 $@"UP: {sentBytes / ONE_KIBIBYTE:N} KiB/s, {sentPackets} pckt/s, {LastSentBytes / ONE_KIBIBYTE:N} KiB, {LastSentPackets} pckt
 DOWN: {receivedBytes / ONE_KIBIBYTE:N} KiB/s, {receivedPackets} pckt/s, {LastReceivedBytes / ONE_KIBIBYTE:N} KiB, {LastReceivedPackets} pckt
-PING: {NetManager.ServerChannel?.Ping ?? -1} ms");
+PING: {NetManager.ServerChannel?.Ping ?? -1} ms, MTU: {NetManager.ServerChannel?.CurrentMtu} B");
         }
     }
 }
diff --git a/Robust.Shared/Network/INetChannel.cs b/Robust.Shared/Network/INetChannel.cs
index 802d1bdd6e..90fd25044d 100644
--- a/Robust.Shared/Network/INetChannel.cs
+++ b/Robust.Shared/Network/INetChannel.cs
@@ -67,6 +67,13 @@ namespace Robust.Shared.Network
         /// </summary>
         bool IsHandshakeComplete { get; }
 
+        /// <summary>
+        /// Diagnostic indicating the maximum transmission unit being used for this connection.
+        /// </summary>
+        /// <seealso cref="CVars.NetMtu"/>
+        [ViewVariables]
+        public int CurrentMtu { get; }
+
         /// <summary>
         ///     Creates a new NetMessage to be filled up and sent.
         /// </summary>
@@ -94,6 +101,5 @@ namespace Robust.Shared.Network
         /// <param name="reason">Reason why it was disconnected.</param>
         /// <param name="sendBye">If false, we ghost the remote client and don't tell them they got disconnected properly.</param>
         void Disconnect(string reason, bool sendBye);
-
     }
 }
diff --git a/Robust.Shared/Network/NetManager.NetChannel.cs b/Robust.Shared/Network/NetManager.NetChannel.cs
index 7bc9074bd4..2bf2cd0b12 100644
--- a/Robust.Shared/Network/NetManager.NetChannel.cs
+++ b/Robust.Shared/Network/NetManager.NetChannel.cs
@@ -51,6 +51,8 @@ namespace Robust.Shared.Network
             // Only used on server, contains the encryption to use for this channel.
             public NetEncryption? Encryption { get; set; }
 
+            [ViewVariables] public int CurrentMtu => _connection.CurrentMTU;
+
             /// <summary>
             ///     Creates a new instance of a NetChannel.
             /// </summary>
diff --git a/Robust.UnitTesting/RobustIntegrationTest.NetManager.cs b/Robust.UnitTesting/RobustIntegrationTest.NetManager.cs
index 04f822384a..29a5d333dd 100644
--- a/Robust.UnitTesting/RobustIntegrationTest.NetManager.cs
+++ b/Robust.UnitTesting/RobustIntegrationTest.NetManager.cs
@@ -440,6 +440,7 @@ namespace Robust.UnitTesting
                 public NetUserData UserData { get; }
                 // integration tests don't simulate serializer handshake so this is always true.
                 public bool IsHandshakeComplete => true;
+                public int CurrentMtu => 1000; // Arbitrary.
 
                 // TODO: Should this port value make sense?
                 public IPEndPoint RemoteEndPoint { get; } = new(IPAddress.Loopback, 1212);