Trimmable Support (#522)

* Trimmable Support
* Change macOS image

Author: kayoub5

Diff for: SharpPcap/LibPcap/LibPcapSafeNativeMethods.Resolver.cs

@@ -41,7 +41,7 @@ static LibPcapSafeNativeMethods()
         /// </summary>
         private static void RegisterResolver()
         {
-            NativeLibraryHelper.SetDllImportResolver(typeof(LibPcapSafeNativeMethods).Assembly, Resolver);
+            NativeLibrary.SetDllImportResolver(typeof(LibPcapSafeNativeMethods).Assembly, Resolver);
         }
 
         public static IntPtr Resolver(string libraryName, Assembly assembly, DllImportSearchPath? searchPath)
@@ -69,7 +69,7 @@ public static IntPtr Resolver(string libraryName, Assembly assembly, DllImportSe
 
             foreach (var name in names)
             {
-                if (NativeLibraryHelper.TryLoad(name, out var handle))
+                if (NativeLibrary.TryLoad(name, out var handle))
                 {
                     return handle;
                 }

Diff for: SharpPcap/LibPcap/NativeLibraryHelper.cs renamed to SharpPcap/LibPcap/NativeLibrary.cs

@@ -5,15 +5,24 @@
 using System.Reflection;
 using System.Runtime.InteropServices;
 
+#if !NET8_0_OR_GREATER
 namespace SharpPcap.LibPcap
 {
-    class NativeLibraryHelper
+    /**
+     * Helper class that uses reflection to access System.Runtime.InteropServices.NativeLibrary
+     * This is needed in order to keep netstandard compatiblity
+     * 
+     * We compile two variants of the DLL, one trimmable but requires .NET 8 thus have NativeLibrary available directly
+     * and one that uses .NET standard, with no trimming support
+     * 
+     */
+    class NativeLibrary
     {
 
         public delegate IntPtr DllImportResolver(string libraryName, Assembly assembly, DllImportSearchPath? searchPath);
 
         private static readonly Type NativeLibraryType;
-        static NativeLibraryHelper()
+        static NativeLibrary()
         {
             NativeLibraryType = typeof(DllImportSearchPath).Assembly
                 .GetType("System.Runtime.InteropServices.NativeLibrary");
@@ -66,3 +75,4 @@ public static bool TryLoad(string libraryPath, out IntPtr handle)
         }
     }
 }
+#endif

Diff for: SharpPcap/LibPcap/PcapDevice.cs

@@ -525,10 +525,10 @@ public static IEnumerable<RawCapture> GetSequence(ICaptureDevice dev, bool maskE
                             break;
                         packet = e.GetPacket();
                     }
-                    catch (PcapException pe)
+                    catch (PcapException)
                     {
                         if (!maskExceptions)
-                            throw pe;
+                            throw;
                     }
 
                     if (packet == null)

Diff for: SharpPcap/SharpPcap.csproj

@@ -7,7 +7,7 @@ SPDX-License-Identifier: MIT
 -->
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFramework>netstandard2.0</TargetFramework>
+    <TargetFrameworks>netstandard2.0;net8.0</TargetFrameworks>
     <Version>6.3.0</Version>
     <Description>A packet capture framework for .NET</Description>
     <Authors>Tamir Gal, Chris Morgan and others</Authors>
@@ -24,10 +24,12 @@ SPDX-License-Identifier: MIT
       It provides an API for capturing, injecting, analyzing and building packets using any .NET language such as C# and VB.NET.
     </Description>
     <PackageLicenseExpression>MIT</PackageLicenseExpression>
-    <LangVersion>7.3</LangVersion>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <Deterministic>true</Deterministic>
   </PropertyGroup>
+  <PropertyGroup Condition=" '$(TargetFramework)' != 'netstandard2.0' ">
+	<IsTrimmable>true</IsTrimmable>
+  </PropertyGroup>
   <ItemGroup>
     <PackageReference Include="PacketDotNet" Version="1.4.7" />
     <PackageReference Include="System.Memory" Version="4.5.5" />

Diff for: SharpPcap/Tunneling/WinTap/WinTapDriver.cs

@@ -4,6 +4,7 @@
 
 using Microsoft.Win32.SafeHandles;
 using System;
+using System.Buffers.Binary;
 using System.ComponentModel;
 using System.IO;
 using System.Net;
@@ -81,7 +82,11 @@ internal static void SetMediaStatus(SafeFileHandle handle, bool connected)
             int value = connected ? 1 : 0;
             Span<byte> inBuffer = stackalloc byte[4];
             Span<byte> outBuffer = stackalloc byte[4];
+#if NET8_0_OR_GREATER
+            MemoryMarshal.Write(inBuffer, in value);
+#else
             MemoryMarshal.Write(inBuffer, ref value);
+#endif
             TapControl(handle, TapIoControl.SetMediaStatus, inBuffer, ref outBuffer);
         }
 

Diff for: azure-pipelines.yml

@@ -29,7 +29,7 @@ jobs:
 
 - job: macos
   pool:
-    vmImage: macOS-11
+    vmImage: macOS-12
   steps:
   - script: sudo -E bash scripts/install-dotnet.sh
   - script: sudo -E bash scripts/install-libpcap.sh