From c6d20bcc6af36a3759bc462025161fe71e77b39f Mon Sep 17 00:00:00 2001
From: Jonas Arnold <jonas.arnold@live.de>
Date: Wed, 10 May 2023 11:36:49 +0200
Subject: [PATCH] Improved stability of Tcp/Udp Reading/Writing

---
 MultiTerm.Protocols/CommunicationProtocol.cs |  2 +-
 MultiTerm.Protocols/Tcp/TcpClientProtocol.cs | 12 +++++++++
 MultiTerm.Protocols/Udp/UdpProtocol.cs       | 26 +++++++++++++++++---
 3 files changed, 35 insertions(+), 5 deletions(-)

diff --git a/MultiTerm.Protocols/CommunicationProtocol.cs b/MultiTerm.Protocols/CommunicationProtocol.cs
index cb68dd2..1ddf17a 100644
--- a/MultiTerm.Protocols/CommunicationProtocol.cs
+++ b/MultiTerm.Protocols/CommunicationProtocol.cs
@@ -151,7 +151,7 @@ public abstract class CommunicationProtocol : ICommunicationProtocol
         else
         {
             this.logger.LogWarn($"'{nameof(Connect)}()' failed to connect to protocol, did not start reading thread.", nameof(CommunicationProtocol));
-            this.messenger.Send<IUserInterfaceMessage>(new GenericUserInterfaceMessage("Failed to connect to protocol, for more information please check logfile.", MessageImportance.High));
+            this.messenger.Send<IUserInterfaceMessage>(new GenericUserInterfaceMessage($"Failed to connect to '{this.GetProtocolAndInstanceIdentifier()}'. For more information please check logfile.", MessageImportance.High));
             return false;
         }
     }
diff --git a/MultiTerm.Protocols/Tcp/TcpClientProtocol.cs b/MultiTerm.Protocols/Tcp/TcpClientProtocol.cs
index 64cd407..7378448 100644
--- a/MultiTerm.Protocols/Tcp/TcpClientProtocol.cs
+++ b/MultiTerm.Protocols/Tcp/TcpClientProtocol.cs
@@ -134,6 +134,18 @@ public class TcpClientProtocol : CommunicationProtocol
                 this.OnUnintentionallyDisconnected();
                 break;  // break loop
             }
+            catch (IOException ioEx)
+            {
+                // socket exception and timeout => normal use case
+                if (ioEx.InnerException is SocketException sockEx && sockEx?.SocketErrorCode == SocketError.TimedOut) { }
+                // other IO Exception
+                else
+                {
+                    this.logger.LogException(ioEx, $"IOException while reading data in {nameof(InternalRead)}", nameof(TcpClientProtocol));
+                    this.messenger.Send<IUserInterfaceMessage>(new StoppedReadingUIMessage(this, ioEx.ToString()));
+                    break; // break loop
+                }
+            }
             catch (Exception ex)
             {
                 this.logger.LogException(ex, $"Exception while reading data in {nameof(InternalRead)}", nameof(TcpClientProtocol));
diff --git a/MultiTerm.Protocols/Udp/UdpProtocol.cs b/MultiTerm.Protocols/Udp/UdpProtocol.cs
index c948668..353c35c 100644
--- a/MultiTerm.Protocols/Udp/UdpProtocol.cs
+++ b/MultiTerm.Protocols/Udp/UdpProtocol.cs
@@ -5,6 +5,7 @@ using MultiTerm.Protocols.Helpers;
 using MultiTerm.Protocols.Model;
 using MultiTerm.Protocols.Network;
 using MultiTerm.Protocols.Types;
+using System.Net;
 using System.Net.Sockets;
 
 namespace MultiTerm.Protocols.Udp;
@@ -19,6 +20,9 @@ public class UdpProtocol : CommunicationProtocol
     private UdpClient? receivingUdpClient;
     private UdpClient? sendingUdpClient;
 
+    private const int ReadTimeoutMs = 100;       // milliseconds until the read operation timeouts
+    private const int WriteTimeoutMs = 100;      // milliseconds until the write operation timeouts
+
     public UdpProtocol(ILogger logger, IMessenger messenger) : base(logger, messenger) { }
 
     protected override bool InternalConnect(IProtocolSettings settings)
@@ -74,6 +78,10 @@ public class UdpProtocol : CommunicationProtocol
             return false;
         }
 
+        // set static settings
+        this.receivingUdpClient.Client.ReceiveTimeout = ReadTimeoutMs;
+        this.sendingUdpClient.Client.SendTimeout = WriteTimeoutMs;
+
         return true;
     }
 
@@ -101,14 +109,15 @@ public class UdpProtocol : CommunicationProtocol
 
     protected override void InternalRead(CancellationToken ct)
     {
-        while(ct.IsCancellationRequested == false)
+        while (ct.IsCancellationRequested == false)
         {
             // try receive message
-            UdpReceiveResult receivedResult;
+            IPEndPoint? remoteEndPoint = null;
+            byte[] receivedBytes = Array.Empty<byte>();
             try
             {
                 // will throw ObjectDisposedException if null
-                receivedResult = this.receivingUdpClient!.ReceiveAsync(ct).GetAwaiter().GetResult(); 
+                receivedBytes = this.receivingUdpClient!.Receive(ref remoteEndPoint);
             }
             catch (OperationCanceledException) // intentionally cancelled => just break
             {
@@ -120,6 +129,16 @@ public class UdpProtocol : CommunicationProtocol
                 this.OnUnintentionallyDisconnected();
                 break;  // break loop
             }
+            catch (SocketException sockEx)
+            {
+                // timeout = normal use case
+                if (sockEx.SocketErrorCode != SocketError.TimedOut)
+                {
+                    this.logger.LogException(sockEx, $"SocketException while reading data in {nameof(InternalRead)}", nameof(UdpProtocol));
+                    this.messenger.Send<IUserInterfaceMessage>(new StoppedReadingUIMessage(this, sockEx.SocketErrorCode.ToString()));
+                    break; // break loop
+                }
+            }
             catch (Exception ex)
             {
                 this.logger.LogException(ex, $"Exception while reading data in {nameof(InternalRead)}", nameof(UdpProtocol));
@@ -128,7 +147,6 @@ public class UdpProtocol : CommunicationProtocol
             }
 
             // any data received?
-            byte[] receivedBytes = receivedResult.Buffer;
             if (receivedBytes.Length > 0)
             {
                 foreach (byte b in receivedBytes)