Allow GrpcChannel to use WinHttpHandler on Windows Server 2019

src/Grpc.Net.Client/GrpcChannel.cs

@@ -185,19 +185,9 @@ internal GrpcChannel(Uri address, GrpcChannelOptions channelOptions) : base(addr
             Log.AddressPathUnused(Logger, Address.OriginalString);
         }
 
-        // Grpc.Net.Client + .NET Framework + WinHttpHandler requires features in WinHTTP, shipped in Windows, to work correctly.
-        // This scenario is supported in these versions of Windows or later:
-        // -Windows Server 2022 has partial support.
-        //    -Unary and server streaming methods are supported.
-        //    -Client and bidi streaming methods aren't supported.
-        // -Windows 11 has full support.
-        //
-        // GrpcChannel validates the Windows version is WinServer2022 or later. Win11 version number is greater than WinServer2022.
-        // Note that this doesn't block using unsupported client and bidi streaming methods on WinServer2022.
-        const int WinServer2022BuildVersion = 20348;
         if (HttpHandlerType == HttpHandlerType.WinHttpHandler &&
             OperatingSystem.IsWindows &&
-            OperatingSystem.OSVersion.Build < WinServer2022BuildVersion)
+            !ValidateWinHttpHandlerOperatingSystemVersion())
         {
             throw new InvalidOperationException("The channel configuration isn't valid on this operating system. " +
                 "The channel is configured to use WinHttpHandler and the current version of Windows " +
@@ -206,6 +196,34 @@ internal GrpcChannel(Uri address, GrpcChannelOptions channelOptions) : base(addr
         }
     }
 
+    private bool ValidateWinHttpHandlerOperatingSystemVersion()
+    {
+        // Grpc.Net.Client + .NET Framework + WinHttpHandler requires features in WinHTTP, shipped in Windows, to work correctly.
+        // This scenario is supported in these versions of Windows or later:
+        // -Windows Server 2019 and Windows Server 2022 have partial support.
+        //    -Unary and server streaming methods are supported.
+        //    -Client and bidi streaming methods aren't supported.
+        // -Windows 11 has full support.
+        const int WinServer2022BuildVersion = 20348;
+        const int WinServer2019BuildVersion = 17763;
+
+        // Validate the Windows version is WinServer2022 or later. Win11 version number is greater than WinServer2022.
+        // Note that this doesn't block using unsupported client and bidi streaming methods on WinServer2022.
+        if (OperatingSystem.OSVersion.Build >= WinServer2022BuildVersion)
+        {
+            return true;
+        }
+
+        // Validate the Windows version is WinServer2019. Its build numbers are mixed with Windows 10, so we must check
+        // the OS version is Windows Server and the build number together to avoid allowing Windows 10.
+        if (OperatingSystem.IsWindowsServer && OperatingSystem.OSVersion.Build >= WinServer2019BuildVersion)
+        {
+            return true;
+        }
+
+        return false;
+    }
+
     private void ResolveCredentials(GrpcChannelOptions channelOptions, out bool isSecure, out List<CallCredentials>? callCredentials)
     {
         if (channelOptions.Credentials != null)

src/Grpc.Net.Client/Internal/NtDll.cs

@@ -16,8 +16,6 @@
 
 #endregion
 
-#if !NET5_0_OR_GREATER
-
 using System.Runtime.InteropServices;
 
 namespace Grpc.Net.Client.Internal;
@@ -27,19 +25,25 @@ namespace Grpc.Net.Client.Internal;
 /// </summary>
 internal static class NtDll
 {
+#pragma warning disable SYSLIB1054 // Use 'LibraryImportAttribute' instead of 'DllImportAttribute' to generate P/Invoke marshalling code at compile time
     [DllImport("ntdll.dll", SetLastError = true, CharSet = CharSet.Unicode)]
     internal static extern NTSTATUS RtlGetVersion(ref OSVERSIONINFOEX versionInfo);
+#pragma warning restore SYSLIB1054 // Use 'LibraryImportAttribute' instead of 'DllImportAttribute' to generate P/Invoke marshalling code at compile time
 
-    internal static Version DetectWindowsVersion()
+    internal static void DetectWindowsVersion(out Version version, out bool isWindowsServer)
     {
-        var osVersionInfo = new OSVERSIONINFOEX { OSVersionInfoSize = Marshal.SizeOf(typeof(OSVERSIONINFOEX)) };
+        // https://learn.microsoft.com/en-us/windows/win32/api/winnt/ns-winnt-osversioninfoexa
+        const byte VER_NT_SERVER = 3;
+
+        var osVersionInfo = new OSVERSIONINFOEX { OSVersionInfoSize = Marshal.SizeOf<OSVERSIONINFOEX>() };
 
         if (RtlGetVersion(ref osVersionInfo) != NTSTATUS.STATUS_SUCCESS)
         {
             throw new InvalidOperationException($"Failed to call internal {nameof(RtlGetVersion)}.");
         }
 
-        return new Version(osVersionInfo.MajorVersion, osVersionInfo.MinorVersion, osVersionInfo.BuildNumber, 0);
+        version = new Version(osVersionInfo.MajorVersion, osVersionInfo.MinorVersion, osVersionInfo.BuildNumber, 0);
+        isWindowsServer = osVersionInfo.ProductType == VER_NT_SERVER;
     }
 
     internal enum NTSTATUS : uint
@@ -68,5 +72,3 @@ internal struct OSVERSIONINFOEX
         public byte Reserved;
     }
 }
-
-#endif

src/Grpc.Net.Client/Internal/OperatingSystem.cs

@@ -25,16 +25,20 @@ internal interface IOperatingSystem
     bool IsBrowser { get; }
     bool IsAndroid { get; }
     bool IsWindows { get; }
+    bool IsWindowsServer { get; }
     Version OSVersion { get; }
 }
 
 internal sealed class OperatingSystem : IOperatingSystem
 {
     public static readonly OperatingSystem Instance = new OperatingSystem();
 
+    private readonly Lazy<bool> _isWindowsServer;
+
     public bool IsBrowser { get; }
     public bool IsAndroid { get; }
     public bool IsWindows { get; }
+    public bool IsWindowsServer => _isWindowsServer.Value;
     public Version OSVersion { get; }
 
     private OperatingSystem()
@@ -44,6 +48,19 @@ private OperatingSystem()
         IsWindows = System.OperatingSystem.IsWindows();
         IsBrowser = System.OperatingSystem.IsBrowser();
         OSVersion = Environment.OSVersion.Version;
+
+        // Windows Server detection requires a P/Invoke call to RtlGetVersion.
+        // Get the value lazily so that it is only called if needed.
+        _isWindowsServer = new Lazy<bool>(() =>
+        {
+            if (IsWindows)
+            {
+                NtDll.DetectWindowsVersion(out _, out var isWindowsServer);
+                return isWindowsServer;
+            }
+
+            return false;
+        }, LazyThreadSafetyMode.ExecutionAndPublication);
 #else
         IsAndroid = false;
         IsWindows = RuntimeInformation.IsOSPlatform(OSPlatform.Windows);
@@ -55,7 +72,17 @@ private OperatingSystem()
         //
         // Get correct Windows version directly from Windows by calling RtlGetVersion.
         // https://www.pinvoke.net/default.aspx/ntdll/RtlGetVersion.html
-        OSVersion = IsWindows ? NtDll.DetectWindowsVersion() : Environment.OSVersion.Version;
+        if (IsWindows)
+        {
+            NtDll.DetectWindowsVersion(out var windowsVersion, out var windowsServer);
+            OSVersion = windowsVersion;
+            _isWindowsServer = new Lazy<bool>(() => windowsServer, LazyThreadSafetyMode.ExecutionAndPublication);
+        }
+        else
+        {
+            OSVersion = Environment.OSVersion.Version;
+            _isWindowsServer = new Lazy<bool>(() => false, LazyThreadSafetyMode.ExecutionAndPublication);
+        }
 #endif
     }
 }

test/Grpc.Net.Client.Tests/GetStatusTests.cs

@@ -215,6 +215,7 @@ private class TestOperatingSystem : IOperatingSystem
         public bool IsBrowser { get; set; }
         public bool IsAndroid { get; set; }
         public bool IsWindows { get; set; }
+        public bool IsWindowsServer { get; }
         public Version OSVersion { get; set; } = new Version(1, 2, 3, 4);
     }
 

test/Grpc.Net.Client.Tests/GrpcChannelTests.cs

@@ -614,6 +614,7 @@ private class TestOperatingSystem : IOperatingSystem
         public bool IsBrowser { get; set; }
         public bool IsAndroid { get; set; }
         public bool IsWindows { get; set; }
+        public bool IsWindowsServer { get; }
         public Version OSVersion { get; set; } = new Version(1, 2, 3, 4);
     }
 

test/Grpc.Net.Client.Tests/OperatingSystemTests.cs

@@ -29,15 +29,28 @@ public class OperatingSystemTests
     [Platform("Win", Reason = "Only runs on Windows where ntdll.dll is present.")]
     public void DetectWindowsVersion_Windows_MatchesEnvironment()
     {
-        // It is safe to compare Environment.OSVersion.Version on netfx because tests have no compatibilty setting.
-        Assert.AreEqual(Environment.OSVersion.Version, NtDll.DetectWindowsVersion());
+        NtDll.DetectWindowsVersion(out var version, out _);
+
+        // It is safe to compare Environment.OSVersion.Version on netfx because tests have no compatibility setting.
+        Assert.AreEqual(Environment.OSVersion.Version, version);
+    }
+
+    [Test]
+    [Platform("Win", Reason = "Only runs on Windows where ntdll.dll is present.")]
+    public void InstanceAndIsWindowsServer_Windows_MatchesEnvironment()
+    {
+        NtDll.DetectWindowsVersion(out var version, out var isWindowsServer);
+
+        Assert.AreEqual(true, OperatingSystem.Instance.IsWindows);
+        Assert.AreEqual(version, OperatingSystem.Instance.OSVersion);
+        Assert.AreEqual(isWindowsServer, OperatingSystem.Instance.IsWindowsServer);
     }
 #endif
 
     [Test]
     public void OSVersion_ModernDotNet_MatchesEnvironment()
     {
-        // It is safe to compare Environment.OSVersion.Version on netfx because tests have no compatibilty setting.
+        // It is safe to compare Environment.OSVersion.Version on netfx because tests have no compatibility setting.
         Assert.AreEqual(Environment.OSVersion.Version, OperatingSystem.Instance.OSVersion);
     }
 }