AvionBlock · lil-jon-crunk · May 18, 2026 · May 9, 2026 · May 10, 2026
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
@@ -0,0 +1,32 @@
+name: CI
+
+on:
+  push:
+    branches: [ main, master ]
+  pull_request:
+    branches: [ main, master ]
+
+jobs:
+  build-test-pack:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup .NET
+        uses: actions/setup-dotnet@v4
+        with:
+          dotnet-version: 10.0.x
+
+      - name: Restore
+        run: dotnet restore OpenPort.Net.sln
+
+      - name: Build
+        run: dotnet build OpenPort.Net.sln --configuration Release --no-restore
+
+      - name: Test
+        run: dotnet test OpenPort.Net.sln --configuration Release --no-build --verbosity normal
+
+      - name: Pack
+        run: dotnet pack OpenPort.Net/OpenPort.Net.csproj --configuration Release --no-build --output artifacts
diff --git a/OpenPort.Net.sln b/OpenPort.Net.sln
@@ -2,15 +2,66 @@
 Microsoft Visual Studio Solution File, Format Version 12.00
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "OpenPort.Net", "OpenPort.Net\OpenPort.Net.csproj", "{1FBFE6D8-7A0D-4967-B073-29EA63B5186F}"
 EndProject
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "tests", "tests", "{0AB3BF05-4346-4AA6-1389-037BE0695223}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "OpenPort.Net.Tests", "tests\OpenPort.Net.Tests\OpenPort.Net.Tests.csproj", "{B95309B1-ED32-4197-ABAF-39A5DF0FF45F}"
+EndProject
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "samples", "samples", "{5D20AA90-6969-D8BD-9DCD-8634F4692FDA}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "OpenPort.Net.Sample", "samples\OpenPort.Net.Sample\OpenPort.Net.Sample.csproj", "{098F1BA7-20E9-47BF-BBBA-AD8F7C92D363}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
+		Debug|x64 = Debug|x64
+		Debug|x86 = Debug|x86
 		Release|Any CPU = Release|Any CPU
+		Release|x64 = Release|x64
+		Release|x86 = Release|x86
 	EndGlobalSection
 	GlobalSection(ProjectConfigurationPlatforms) = postSolution
 		{1FBFE6D8-7A0D-4967-B073-29EA63B5186F}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
 		{1FBFE6D8-7A0D-4967-B073-29EA63B5186F}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{1FBFE6D8-7A0D-4967-B073-29EA63B5186F}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{1FBFE6D8-7A0D-4967-B073-29EA63B5186F}.Debug|x64.Build.0 = Debug|Any CPU
+		{1FBFE6D8-7A0D-4967-B073-29EA63B5186F}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{1FBFE6D8-7A0D-4967-B073-29EA63B5186F}.Debug|x86.Build.0 = Debug|Any CPU
 		{1FBFE6D8-7A0D-4967-B073-29EA63B5186F}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{1FBFE6D8-7A0D-4967-B073-29EA63B5186F}.Release|Any CPU.Build.0 = Release|Any CPU
+		{1FBFE6D8-7A0D-4967-B073-29EA63B5186F}.Release|x64.ActiveCfg = Release|Any CPU
+		{1FBFE6D8-7A0D-4967-B073-29EA63B5186F}.Release|x64.Build.0 = Release|Any CPU
+		{1FBFE6D8-7A0D-4967-B073-29EA63B5186F}.Release|x86.ActiveCfg = Release|Any CPU
+		{1FBFE6D8-7A0D-4967-B073-29EA63B5186F}.Release|x86.Build.0 = Release|Any CPU
+		{B95309B1-ED32-4197-ABAF-39A5DF0FF45F}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{B95309B1-ED32-4197-ABAF-39A5DF0FF45F}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{B95309B1-ED32-4197-ABAF-39A5DF0FF45F}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{B95309B1-ED32-4197-ABAF-39A5DF0FF45F}.Debug|x64.Build.0 = Debug|Any CPU
+		{B95309B1-ED32-4197-ABAF-39A5DF0FF45F}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{B95309B1-ED32-4197-ABAF-39A5DF0FF45F}.Debug|x86.Build.0 = Debug|Any CPU
+		{B95309B1-ED32-4197-ABAF-39A5DF0FF45F}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{B95309B1-ED32-4197-ABAF-39A5DF0FF45F}.Release|Any CPU.Build.0 = Release|Any CPU
+		{B95309B1-ED32-4197-ABAF-39A5DF0FF45F}.Release|x64.ActiveCfg = Release|Any CPU
+		{B95309B1-ED32-4197-ABAF-39A5DF0FF45F}.Release|x64.Build.0 = Release|Any CPU
+		{B95309B1-ED32-4197-ABAF-39A5DF0FF45F}.Release|x86.ActiveCfg = Release|Any CPU
+		{B95309B1-ED32-4197-ABAF-39A5DF0FF45F}.Release|x86.Build.0 = Release|Any CPU
+		{098F1BA7-20E9-47BF-BBBA-AD8F7C92D363}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{098F1BA7-20E9-47BF-BBBA-AD8F7C92D363}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{098F1BA7-20E9-47BF-BBBA-AD8F7C92D363}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{098F1BA7-20E9-47BF-BBBA-AD8F7C92D363}.Debug|x64.Build.0 = Debug|Any CPU
+		{098F1BA7-20E9-47BF-BBBA-AD8F7C92D363}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{098F1BA7-20E9-47BF-BBBA-AD8F7C92D363}.Debug|x86.Build.0 = Debug|Any CPU
+		{098F1BA7-20E9-47BF-BBBA-AD8F7C92D363}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{098F1BA7-20E9-47BF-BBBA-AD8F7C92D363}.Release|Any CPU.Build.0 = Release|Any CPU
+		{098F1BA7-20E9-47BF-BBBA-AD8F7C92D363}.Release|x64.ActiveCfg = Release|Any CPU
+		{098F1BA7-20E9-47BF-BBBA-AD8F7C92D363}.Release|x64.Build.0 = Release|Any CPU
+		{098F1BA7-20E9-47BF-BBBA-AD8F7C92D363}.Release|x86.ActiveCfg = Release|Any CPU
+		{098F1BA7-20E9-47BF-BBBA-AD8F7C92D363}.Release|x86.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(NestedProjects) = preSolution
+		{B95309B1-ED32-4197-ABAF-39A5DF0FF45F} = {0AB3BF05-4346-4AA6-1389-037BE0695223}
+		{098F1BA7-20E9-47BF-BBBA-AD8F7C92D363} = {5D20AA90-6969-D8BD-9DCD-8634F4692FDA}
 	EndGlobalSection
 EndGlobal
diff --git a/OpenPort.Net/Discovery/GatewayDiscovery.cs b/OpenPort.Net/Discovery/GatewayDiscovery.cs
@@ -0,0 +1,9 @@
+using System.Net;
+using OpenPort.Net.Internal;
+
+namespace OpenPort.Net.Discovery;
+
+internal sealed class GatewayDiscovery
+{
+    public IPAddress? DiscoverGatewayAddress() => NetworkUtils.GetDefaultGatewayAddress();
+}
diff --git a/OpenPort.Net/Discovery/SsdpDiscovery.cs b/OpenPort.Net/Discovery/SsdpDiscovery.cs
@@ -0,0 +1,105 @@
+using System.Net;
+using System.Net.Sockets;
+using System.Text;
+
+namespace OpenPort.Net.Discovery;
+
+internal sealed class SsdpDiscovery
+{
+    private static readonly IPEndPoint MulticastEndPoint = new(IPAddress.Parse("239.255.255.250"), 1900);
+    private readonly TimeSpan _timeout;
+
+    public SsdpDiscovery(TimeSpan timeout)
+    {
+        _timeout = timeout;
+    }
+
+    public async Task<IReadOnlyList<Uri>> DiscoverInternetGatewayDevicesAsync(CancellationToken cancellationToken)
+    {
+        var searchTargets = new[]
+        {
+            "urn:schemas-upnp-org:device:InternetGatewayDevice:1",
+            "urn:schemas-upnp-org:service:WANIPConnection:1",
+            "urn:schemas-upnp-org:service:WANIPConnection:2",
+            "urn:schemas-upnp-org:service:WANPPPConnection:1"
+        };
+
+        var locations = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
+
+        using var udpClient = new UdpClient(AddressFamily.InterNetwork);
+        udpClient.Client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
+
+        foreach (var searchTarget in searchTargets)
+        {
+            var request = BuildSearchRequest(searchTarget);
+            var bytes = Encoding.ASCII.GetBytes(request);
+            await udpClient.SendAsync(bytes, bytes.Length, MulticastEndPoint).ConfigureAwait(false);
+        }
+
+        using var timeout = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken);
+        timeout.CancelAfter(_timeout);
+
+        while (!timeout.IsCancellationRequested)
+        {
+            try
+            {
+                var response = await ReceiveAsync(udpClient, timeout.Token).ConfigureAwait(false);
+                if (response is null)
+                {
+                    break;
+                }
+
+                var text = Encoding.ASCII.GetString(response.Value.Buffer);
+                var location = ParseHeader(text, "LOCATION");
+                if (Uri.TryCreate(location, UriKind.Absolute, out var uri))
+                {
+                    locations.Add(uri.AbsoluteUri);
+                }
+            }
+            catch (OperationCanceledException) when (timeout.IsCancellationRequested)
+            {
+                break;
+            }
+        }
+
+        return locations.Select(location => new Uri(location)).ToList();
+    }
+
+    private static string BuildSearchRequest(string searchTarget) =>
+        "M-SEARCH * HTTP/1.1\r\n" +
+        "HOST: 239.255.255.250:1900\r\n" +
+        "MAN: \"ssdp:discover\"\r\n" +
+        "MX: 2\r\n" +
+        $"ST: {searchTarget}\r\n\r\n";
+
+    private static string? ParseHeader(string response, string name)
+    {
+        foreach (var line in response.Split(new[] { "\r\n", "\n" }, StringSplitOptions.RemoveEmptyEntries))
+        {
+            var separator = line.IndexOf(':');
+            if (separator <= 0)
+            {
+                continue;
+            }
+
+            if (string.Equals(line[..separator].Trim(), name, StringComparison.OrdinalIgnoreCase))
+            {
+                return line[(separator + 1)..].Trim();
+            }
+        }
+
+        return null;
+    }
+
+    private static async Task<UdpReceiveResult?> ReceiveAsync(UdpClient udpClient, CancellationToken cancellationToken)
+    {
+#if NET8_0_OR_GREATER
+        return await udpClient.ReceiveAsync(cancellationToken).ConfigureAwait(false);
+#else
+        var receiveTask = udpClient.ReceiveAsync();
+        var completed = await Task.WhenAny(receiveTask, Task.Delay(Timeout.InfiniteTimeSpan, cancellationToken)).ConfigureAwait(false);
+        cancellationToken.ThrowIfCancellationRequested();
+        return completed == receiveTask ? receiveTask.Result : null;
+#endif
+    }
+}
diff --git a/OpenPort.Net/Internal/CompilerCompatibility.cs b/OpenPort.Net/Internal/CompilerCompatibility.cs
@@ -0,0 +1,7 @@
+#if NETSTANDARD2_1
+namespace System.Runtime.CompilerServices;
+
+internal static class IsExternalInit
+{
+}
+#endif
diff --git a/OpenPort.Net/Internal/NatPmpMessage.cs b/OpenPort.Net/Internal/NatPmpMessage.cs
@@ -0,0 +1,130 @@
+using System.Net;
+using OpenPort.Net.Models;
+
+namespace OpenPort.Net.Internal;
+
+internal static class NatPmpMessage
+{
+    public const byte Version = 0;
+    public const byte ExternalAddressOpcode = 0;
+    public const byte UdpMapOpcode = 1;
+    public const byte TcpMapOpcode = 2;
+    public const byte ResponseOffset = 128;
+
+    public static byte[] CreateExternalAddressRequest() => [Version, ExternalAddressOpcode];
+
+    public static byte[] CreateMapRequest(PortProtocol protocol, int internalPort, int externalPort, uint lifetimeSeconds)
+    {
+        var request = new byte[12];
+        request[0] = Version;
+        request[1] = ToMapOpcode(protocol);
+        NetworkUtils.WriteUInt16BigEndian(request, 4, internalPort);
+        NetworkUtils.WriteUInt16BigEndian(request, 6, externalPort);
+        NetworkUtils.WriteUInt32BigEndian(request, 8, lifetimeSeconds);
+        return request;
+    }
+
+    public static bool TryParseExternalAddressResponse(
+        byte[] response,
+        out ushort resultCode,
+        out IPAddress? externalAddress)
+    {
+        resultCode = 0;
+        externalAddress = null;
+
+        if (response.Length < 8 || response[0] != Version || response[1] != ExternalAddressOpcode + ResponseOffset)
+        {
+            return false;
+        }
+
+        resultCode = NetworkUtils.ReadUInt16BigEndian(response, 2);
+        if (resultCode != 0)
+        {
+            return true;
+        }
+
+        if (response.Length < 12)
+        {
+            return false;
+        }
+
+        externalAddress = new IPAddress(response.Skip(8).Take(4).ToArray());
+        return true;
+    }
+
+    public static bool TryParseMapResponse(
+        byte[] response,
+        PortProtocol protocol,
+        out NatPmpMapResponse mapResponse)
+    {
+        mapResponse = default;
+        var opcode = ToMapOpcode(protocol);
+
+        if (response.Length < 8 || response[0] != Version || response[1] != opcode + ResponseOffset)
+        {
+            return false;
+        }
+
+        var resultCode = NetworkUtils.ReadUInt16BigEndian(response, 2);
+        if (resultCode != 0)
+        {
+            mapResponse = new NatPmpMapResponse(resultCode, 0, 0, 0);
+            return true;
+        }
+
+        if (response.Length < 16)
+        {
+            return false;
+        }
+
+        mapResponse = new NatPmpMapResponse(
+            resultCode,
+            NetworkUtils.ReadUInt16BigEndian(response, 8),
+            NetworkUtils.ReadUInt16BigEndian(response, 10),
+            NetworkUtils.ReadUInt32BigEndian(response, 12));
+        return true;
+    }
+
+    public static OpenPortStatus MapResultCode(ushort code) =>
+        code switch
+        {
+            0 => OpenPortStatus.Success,
+            1 => OpenPortStatus.NotSupported,
+            2 => OpenPortStatus.Unauthorized,
+            3 => OpenPortStatus.Failed,
+            4 => OpenPortStatus.NoResources,
+            5 => OpenPortStatus.NotSupported,
+            _ => OpenPortStatus.Failed
+        };
+
+    public static string GetResultName(ushort code) =>
+        code switch
+        {
+            0 => "Success",
+            1 => "UnsupportedVersion",
+            2 => "NotAuthorized",
+            3 => "NetworkFailure",
+            4 => "OutOfResources",
+            5 => "UnsupportedOpcode",
+            _ => "Unknown"
+        };
+
+    private static byte ToMapOpcode(PortProtocol protocol) =>
+        protocol == PortProtocol.Udp ? UdpMapOpcode : TcpMapOpcode;
+}
+
+internal readonly struct NatPmpMapResponse
+{
+    public NatPmpMapResponse(ushort resultCode, int internalPort, int externalPort, uint lifetimeSeconds)
+    {
+        ResultCode = resultCode;
+        InternalPort = internalPort;
+        ExternalPort = externalPort;
+        LifetimeSeconds = lifetimeSeconds;
+    }
+
+    public ushort ResultCode { get; }
+    public int InternalPort { get; }
+    public int ExternalPort { get; }
+    public uint LifetimeSeconds { get; }
+}