Changed dot-netty.tcp.reuse-addr to default to 'off-for-windows'

src/core/Akka.API.Tests/CoreAPISpec.ApproveCore.approved.txt

@@ -4758,6 +4758,7 @@ namespace Akka.Util
     public class static RuntimeDetector
     {
         public static readonly bool IsMono;
+        public static readonly bool IsWindows;
     }
     public class static StandardOutWriter
     {

src/core/Akka.Remote.Tests/RemoteConfigSpec.cs

@@ -102,7 +102,7 @@ public void Remoting_should_contain_correct_heliosTCP_values_in_ReferenceConf()
             Assert.Equal(4096, s.Backlog);
             Assert.True(s.TcpNoDelay);
             Assert.True(s.TcpKeepAlive);
-            Assert.True(s.TcpReuseAddr);
+            Assert.Equal("off-for-windows", c.GetString("tcp-reuse-addr"));
             Assert.True(string.IsNullOrEmpty(c.GetString("hostname")));
             Assert.Null(s.PublicPort);
             Assert.Equal(2, s.ServerSocketWorkerPoolSize);

src/core/Akka.Remote/Configuration/Remote.conf

@@ -473,10 +473,10 @@ akka {
 
       # Enables SO_REUSEADDR, which determines when an ActorSystem can open
       # the specified listen port (the meaning differs between *nix and Windows)
-      # Valid values are "on", "off" and "off-for-windows"
+      # Valid values are "on", "off", and "off-for-windows"
       # due to the following Windows bug: http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4476378
       # "off-for-windows" of course means that it's "on" for all other platforms
-      tcp-reuse-addr = on
+      tcp-reuse-addr = off-for-windows
 
       # Used to configure the number of I/O worker threads on server sockets
       server-socket-worker-pool {

src/core/Akka.Remote/Transport/DotNetty/DotNettyTransportSettings.cs

@@ -29,6 +29,27 @@ public static DotNettyTransportSettings Create(ActorSystem system)
             return Create(system.Settings.Config.GetConfig("akka.remote.dot-netty.tcp"));
         }
 
+        /// <summary>
+        /// Adds support for the "off-for-windows" option per https://github.com/akkadotnet/akka.net/issues/3293
+        /// </summary>
+        /// <param name="hoconTcpReuseAddr">The HOCON string for the akka.remote.dot-netty.tcp.reuse-addr option</param>
+        /// <returns><c>true</c> if we should enable REUSE_ADDR for tcp. <c>false</c> otherwise.</returns>
+        internal static bool ResolveTcpReuseAddrOption(string hoconTcpReuseAddr)
+        {
+            switch (hoconTcpReuseAddr.ToLowerInvariant())
+            {
+                case "off-for-windows" when RuntimeDetector.IsWindows:
+                    return false;
+                case "off-for-windows":
+                    return true;
+                case "on":
+                    return true;
+                case "off":
+                default:
+                    return false;
+            }
+        }
+
         public static DotNettyTransportSettings Create(Config config)
         {
             if (config == null) throw new ArgumentNullException(nameof(config), "DotNetty HOCON config was not found (default path: `akka.remote.dot-netty`)");
@@ -61,7 +82,7 @@ public static DotNettyTransportSettings Create(Config config)
                 maxFrameSize: ToNullableInt(config.GetByteSize("maximum-frame-size")) ?? 128000,
                 ssl: config.HasPath("ssl") ? SslSettings.Create(config.GetConfig("ssl")) : SslSettings.Empty,
                 dnsUseIpv6: config.GetBoolean("dns-use-ipv6", false),
-                tcpReuseAddr: config.GetBoolean("tcp-reuse-addr", true),
+                tcpReuseAddr: ResolveTcpReuseAddrOption(config.GetString("tcp-reuse-addr", "off-for-windows")),
                 tcpKeepAlive: config.GetBoolean("tcp-keepalive", true),
                 tcpNoDelay: config.GetBoolean("tcp-nodelay", true),
                 backlog: config.GetInt("backlog", 4096),

src/core/Akka/Util/RuntimeDetector.cs

@@ -6,10 +6,7 @@
 //-----------------------------------------------------------------------
 
 using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
+using System.Runtime.InteropServices;
 
 namespace Akka.Util
 {
@@ -28,6 +25,25 @@ public static class RuntimeDetector
         /// Is <c>true</c> if we're running on a Mono VM. <c>false</c> otherwise.
         /// </summary>
         public static readonly bool IsMono = Type.GetType("Mono.Runtime") != null;
+
+        /// <summary>
+        /// Is <c>true</c> if we've detected Windows as a platform.
+        /// </summary>
+        public static readonly bool IsWindows = _IsWindows();
+
+        /// <summary>
+        /// Private implementation method not meant for public consumption
+        /// </summary>
+        /// <returns><c>true</c> if the current runtime is Windows</returns>
+        private static bool _IsWindows()
+        {
+#if CORECLR
+            return System.Runtime.InteropServices.RuntimeInformation.IsOSPlatform(OSPlatform.Windows);
+#else
+            return System.Environment.OSVersion.Platform != PlatformID.MacOSX &&
+                   System.Environment.OSVersion.Platform != PlatformID.Unix;
+#endif
+        }
     }
 }