PowerDNS Socket (to be changed from custom-implementation to Kestrel with ConnectionHandler)

src/pdns-dhcp/Kea/KeaDhcpLease.cs

@@ -3,6 +3,8 @@ using System.Globalization;
 
 using DotNext.Buffers;
 
+using Microsoft.Toolkit.HighPerformance.Buffers;
+
 namespace pdns_dhcp.Kea;
 
 public static class KeaDhcpLease
@@ -21,7 +23,7 @@ public static class KeaDhcpLease
 		static string SlowPath(int esc_pos, in ReadOnlySpan<char> text)
 		{
 			SpanReader<char> reader = new(text);
-			ArrayBufferWriter<char> writer = new(text.Length);
+			using ArrayPoolBufferWriter<char> writer = new(text.Length);
 			while (reader.RemainingCount > 0)
 			{
 				writer.Write(reader.Read(esc_pos));

src/pdns-dhcp/Kea/KeaDhcpLeaseWatcher.cs

@@ -35,7 +35,7 @@ public sealed class KeaDhcpLeaseWatcher<T> : IHostedService
 
 	public KeaDhcpLeaseWatcher(KeaDhcpServerOptions options, T handler)
 	{
-		Options = options;
+		Options = options = options with { Leases = PathEx.ExpandPath(options.Leases) };
 		_handler = handler;
 
 		var leases = options.Leases.AsSpan();

src/pdns-dhcp/PowerDns/Methods.cs

@@ -3,10 +3,7 @@ using System.Text.Json.Serialization;
 
 namespace pdns_dhcp.PowerDns;
 
-public interface IMethod
-{
-	public abstract static string Method { get; }
-}
+public interface IMethod;
 
 [JsonPolymorphic(TypeDiscriminatorPropertyName = "method")]
 [JsonDerivedType(typeof(InitializeMethod), "initialize")]
@@ -24,12 +21,6 @@ public abstract class Method<TSelf, TParam>(TParam parameters) : Method<TSelf> w
 	public TParam Parameters => parameters;
 }
 
-public class InitializeMethod : Method<InitializeMethod>, IMethod
-{
-	public static string Method => "Initialize";
-}
+public class InitializeMethod : Method<InitializeMethod>, IMethod;
 
-public class LookupMethod : Method<LookupMethod>, IMethod
-{
-	public static string Method => "Lookup";
-}
+public class LookupMethod : Method<LookupMethod>, IMethod;

src/pdns-dhcp/PowerDns/PowerDnsStreamClient.cs

@@ -1,7 +1,5 @@
 using System.Text.Json;
 
-using Stl.Async;
-
 namespace pdns_dhcp.PowerDns;
 
 public class PowerDnsStreamClient : IDisposable
@@ -17,32 +15,63 @@ public class PowerDnsStreamClient : IDisposable
 
 	~PowerDnsStreamClient()
 	{
-		Dispose();
+		DisposeCore();
 	}
 
 	public void Dispose()
 	{
-		using (_cts)
-		using (_stream)
+		_cts.Cancel();
+		if (Interlocked.Exchange(ref _task, null!) is { } task)
 		{
-			_cts.Cancel();
-			_task.GetAwaiter().GetResult();
+			task
+				.ConfigureAwait(ConfigureAwaitOptions.SuppressThrowing)
+				.GetAwaiter().GetResult();
 		}
+
+		DisposeCore();
+
 		GC.SuppressFinalize(this);
 	}
 
 	public void Start(CancellationToken stoppingToken)
 	{
-		using var other = Interlocked.Exchange(ref _cts, CancellationTokenSource.CreateLinkedTokenSource(stoppingToken));
-		_task = Run(_cts.Token);
-		other.Cancel();
+		var cts = CancellationTokenSource.CreateLinkedTokenSource(stoppingToken);
+		using var old = Interlocked.Exchange(ref _cts, cts);
+		old.Cancel();
+		_task = Run(cts.Token);
+	}
+
+	private void DisposeCore()
+	{
+		_cts.Dispose();
+		_stream.Dispose();
 	}
 
 	private async Task Run(CancellationToken stoppingToken)
 	{
-		while (!stoppingToken.IsCancellationRequested)
+		try
 		{
-			await JsonSerializer.DeserializeAsync<Method>(_stream, cancellationToken: stoppingToken);
+			while (!stoppingToken.IsCancellationRequested)
+			{
+				switch (await JsonSerializer.DeserializeAsync<Method>(_stream, cancellationToken: stoppingToken).ConfigureAwait(false))
+				{
+					case InitializeMethod init:
+						break;
+				
+					case LookupMethod lookup:
+						break;
+				
+					default:
+						break;
+				}
+			}
+		}
+		finally
+		{
+			if (Interlocked.Exchange(ref _task, null!) is not null)
+			{
+				Dispose();
+			}
 		}
 	}
 }

src/pdns-dhcp/Program.cs

@@ -1,6 +1,6 @@
-using Microsoft.Extensions.Configuration;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
-using Microsoft.Extensions.Hosting;
 
 using pdns_dhcp.Kea;
 using pdns_dhcp.Options;
@@ -9,7 +9,7 @@ using pdns_dhcp.Services;
 
 using Stl.Interception;
 
-var builder = Host.CreateApplicationBuilder(args);
+var builder = WebApplication.CreateBuilder(args);
 builder.Services.Configure<DhcpOptions>(builder.Configuration.GetRequiredSection("Dhcp"));
 builder.Services.Configure<PowerDnsOptions>(builder.Configuration.GetRequiredSection("PowerDns"));
 

src/pdns-dhcp/Services/PowerDnsBackend.cs

@@ -16,8 +16,17 @@ public class PowerDnsBackend : BackgroundService
 	public PowerDnsBackend(IOptions<PowerDnsOptions> options, IPowerDnsFactory socketFactory)
 	{
 		_factory = socketFactory;
-		_socket = new(SocketType.Stream, ProtocolType.Unknown);
-		_socket.Bind(new UnixDomainSocketEndPoint(options.Value.Listener.Socket));
+		_socket = new(AddressFamily.Unix, SocketType.Stream, ProtocolType.Unspecified);
+		var path = PathEx.ExpandPath(options.Value.Listener.Socket);
+		FileInfo file = new(path);
+		file.Directory!.Create();
+		file.Delete();
+		_socket.Bind(new UnixDomainSocketEndPoint(path));
+	}
+
+	~PowerDnsBackend()
+	{
+		DisposeCore();
 	}
 
 	protected override async Task ExecuteAsync(CancellationToken stoppingToken)
@@ -29,4 +38,16 @@ public class PowerDnsBackend : BackgroundService
 				.Start(stoppingToken);
 		}
 	}
+
+	public override void Dispose()
+	{
+		base.Dispose();
+		DisposeCore();
+		GC.SuppressFinalize(this);
+	}
+
+	private void DisposeCore()
+	{
+		_socket.Dispose();
+	}
 }

src/pdns-dhcp/System/IO/Paths.cs

@@ -0,0 +1,113 @@
+#if !(LINUX || MACOS || WINDOWS)
+#define TARGET_ANY
+#endif
+
+#if TARGET_ANY || LINUX
+#define TARGET_LINUX
+#endif
+#if TARGET_ANY || MACOS
+#define TARGET_MACOS
+#endif
+#if TARGET_ANY || WINDOWS
+#define TARGET_WINDOWS
+#endif
+
+using System.Buffers;
+
+using Microsoft.Toolkit.HighPerformance.Buffers;
+
+namespace System.IO;
+
+public static class PathEx
+{
+	public static string ExpandPath(string path)
+	{
+#if TARGET_ANY
+		if (OperatingSystem.IsLinux() || OperatingSystem.IsMacOS())
+		{
+#endif
+#if TARGET_LINUX || TARGET_MACOS
+			return ExpandPathUnixImpl(path);
+#endif
+#if TARGET_ANY
+		}
+		else if (OperatingSystem.IsWindows())
+		{
+#endif
+#if TARGET_WINDOWS
+			return ExpandPathWindowsImpl(path);
+#endif
+#if TARGET_ANY
+		}
+		else
+		{
+			throw new PlatformNotSupportedException();
+		}
+#endif
+	}
+
+#if TARGET_LINUX || TARGET_MACOS
+	private static string ExpandPathUnixImpl(string path)
+	{
+		if (string.IsNullOrWhiteSpace(path))
+		{
+			return path;
+		}
+
+		var reader = new SequenceReader<char>(new(path.AsMemory()));
+		if (!reader.TryReadTo(out ReadOnlySpan<char> read, '$'))
+		{
+			return path;
+		}
+
+		using ArrayPoolBufferWriter<char> result = new();
+		while (true)
+		{
+			result.Write(read);
+
+			int skip = 0;
+			if (reader.UnreadSpan[0] == '{' && reader.UnreadSpan.IndexOf('}') is not -1 and int s)
+			{
+				read = reader.UnreadSpan[1..s];
+				skip = s + 1;
+			}
+			else
+			{
+				var propertyReader = new SequenceReader<char>(reader.UnreadSequence);
+				while (!propertyReader.End && propertyReader.UnreadSpan[0] is char c && (c == '_' || char.IsAsciiLetterOrDigit(c)))
+				{
+					propertyReader.Advance(1);
+				}
+
+				read = reader.UnreadSpan[..(int)propertyReader.Consumed];
+				skip = read.Length;
+			}
+
+			if (skip != 0 && Environment.GetEnvironmentVariable(read.ToString()) is { } env)
+			{
+				result.Write(env);
+				reader.Advance(skip);
+			}
+			else
+			{
+				result.Write(['$']);
+			}
+
+			if (!reader.TryReadTo(out read, '$'))
+			{
+				break;
+			}
+		}
+
+		result.Write(reader.UnreadSpan);
+		return result.WrittenSpan.ToString();
+	}
+#endif
+
+#if TARGET_WINDOWS
+	private static string ExpandPathWindowsImpl(string path)
+	{
+		return Environment.ExpandEnvironmentVariables(path);
+	}
+#endif
+}

src/pdns-dhcp/appsettings.Development.json

@@ -8,5 +8,10 @@
 				"Leases": "../../ext/kea/dhcp6.leases"
 			}
 		}
+	},
+	"PowerDns": {
+		"Listener": {
+			"Socket": "${XDG_RUNTIME_DIR}/pdns-dhcp/pdns.sock"
+		}
 	}
 }

src/pdns-dhcp/pdns-dhcp.csproj

@@ -9,6 +9,10 @@
 		<EnableConfigurationBindingGenerator>true</EnableConfigurationBindingGenerator>
 	</PropertyGroup>
 
+	<ItemGroup>
+		<FrameworkReference Include="Microsoft.AspNetCore.App" />
+	</ItemGroup>
+
 	<ItemGroup>
 		<PackageReference Include="DotNext" Version="4.15.2" />
 		<PackageReference Include="Microsoft.Extensions.Configuration.Binder" Version="8.0.0" />