[SocketException]: New Constructor with string? for SocketException

src/libraries/Common/src/System/Net/Internals/SocketExceptionFactory.Unix.cs

@@ -9,7 +9,7 @@ internal static partial class SocketExceptionFactory
     {
         public static SocketException CreateSocketException(SocketError errorCode, int platformError)
         {
-            return new ExtendedSocketException(errorCode, platformError);
+            return new SocketException(errorCode, (uint)platformError);
         }
     }
 }

src/libraries/Common/src/System/Net/Internals/SocketExceptionFactory.cs

@@ -7,29 +7,9 @@ namespace System.Net.Internals
 {
     internal static partial class SocketExceptionFactory
     {
-        private sealed class ExtendedSocketException : SocketException
-        {
-            private readonly EndPoint? _endPoint;
-
-            public ExtendedSocketException(int errorCode, EndPoint? endPoint)
-                : base(errorCode)
-            {
-                _endPoint = endPoint;
-            }
-
-            public ExtendedSocketException(SocketError socketError, int platformError)
-                : base((int)socketError)
-            {
-                HResult = platformError;
-            }
-
-            public override string Message =>
-                (_endPoint == null) ? base.Message : base.Message + " " + _endPoint.ToString();
-        }
-
         public static SocketException CreateSocketException(int socketError, EndPoint? endPoint)
         {
-            return new ExtendedSocketException(socketError, endPoint);
+            return new SocketException(socketError, endPoint?.ToString());
         }
     }
 }

src/libraries/System.Net.Primitives/ref/System.Net.Primitives.cs

@@ -471,6 +471,7 @@ public partial class SocketException : System.ComponentModel.Win32Exception
     {
         public SocketException() { }
         public SocketException(int errorCode) { }
+        public SocketException(int errorCode, string? message) { }
         protected SocketException(System.Runtime.Serialization.SerializationInfo serializationInfo, System.Runtime.Serialization.StreamingContext streamingContext) { }
         public override int ErrorCode { get { throw null; } }
         public override string Message { get { throw null; } }

src/libraries/System.Net.Primitives/src/System/Net/SocketException.cs

@@ -30,12 +30,23 @@ public SocketException(int errorCode) : this((SocketError)errorCode)
             // but that's the least bad option right now.
         }
 
+        /// <summary>Initializes a new instance of the <see cref='System.Net.Sockets.SocketException'/> class with the specified error code and optional message.</summary>
+        public SocketException(int errorCode, string? message) : this((SocketError)errorCode, message)
+        {
+        }
+
         /// <summary>Creates a new instance of the <see cref='System.Net.Sockets.SocketException'/> class with the specified error code as SocketError.</summary>
         internal SocketException(SocketError socketError) : base(GetNativeErrorForSocketError(socketError))
         {
             _errorCode = socketError;
         }
 
+        /// <summary>Initializes a new instance of the <see cref='System.Net.Sockets.SocketException'/> class with the specified error code as SocketError and optional message.</summary>
+        internal SocketException(SocketError socketError, string? message) : base(GetNativeErrorForSocketError(socketError), message)
+        {
+            _errorCode = socketError;
+        }
+
         public override string Message => base.Message;
 
         public SocketError SocketErrorCode => _errorCode;

src/libraries/System.Net.Primitives/tests/FunctionalTests/SocketExceptionTest.cs

@@ -0,0 +1,53 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Net.Sockets;
+using Xunit;
+
+namespace System.Net.Primitives.Functional.Tests
+{
+    public static class SocketExceptionTest
+    {
+        [Fact]
+        public static void Create_AllErrorCodes_Success()
+        {
+            foreach (SocketError error in Enum.GetValues(typeof(SocketError)))
+            {
+                SocketException e = new SocketException((int)error);
+                Assert.Equal(error, e.SocketErrorCode);
+                Assert.Null(e.InnerException);
+                Assert.NotNull(e.Message);
+            }
+        }
+
+        [Fact]
+        public static void Create_ExceptionWithMessage_Success()
+        {
+            const string message = "Hello World";
+            SocketException e = new SocketException((int)SocketError.AccessDenied, message);
+            Assert.Equal(SocketError.AccessDenied, e.SocketErrorCode);
+            Assert.Null(e.InnerException);
+            Assert.Equal(message, e.Message);
+            Assert.Contains(message, e.ToString());
+        }
+
+        [Fact]
+        public static void Create_SocketConnectException_Success()
+        {
+            using (Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp))
+            {
+                IPEndPoint ep = new IPEndPoint(IPAddress.Loopback, 55555);
+                Assert.ThrowsAsync<SocketException>(() => socket.ConnectAsync(ep));
+                try
+                {
+                    socket.Connect(ep);
+                    Assert.Fail("Socket Connect should throw SocketException in this case.");
+                }
+                catch(SocketException ex)
+                {
+                    Assert.Equal(ep.ToString(), ex.Message);
+                }
+            }
+        }
+    }
+}

src/libraries/System.Net.Primitives/tests/FunctionalTests/System.Net.Primitives.Functional.Tests.csproj

@@ -25,7 +25,7 @@
     <Compile Include="LoggingTest.cs" />
     <Compile Include="RequestCachePolicyTest.cs" />
     <Compile Include="CookieContainerAddTest.cs" />
-    <Compile Include="$(CommonTestPath)System\Diagnostics\Tracing\TestEventListener.cs"
-             Link="Common\System\Diagnostics\Tracing\TestEventListener.cs" />
+    <Compile Include="$(CommonTestPath)System\Diagnostics\Tracing\TestEventListener.cs" Link="Common\System\Diagnostics\Tracing\TestEventListener.cs" />
+    <Compile Include="SocketExceptionTest.cs" />
   </ItemGroup>
 </Project>