Add managed codec DSP and initial control server

2026-09-15 22:51:33 +02:00
parent 2df79cdd4c
commit 4067bab7c2
52 changed files with 2503 additions and 20 deletions
@@ -0,0 +1,169 @@
+using System.Buffers;
+using System.Buffers.Binary;
+using System.Net.Sockets;
+using System.Threading.Channels;
+using Google.Protobuf;
+using VoiceCat.Crypto;
+using VoiceCat.Protocol;
+using Voicecat.V1;
+
+namespace VoiceCat.Server.Transport;
+
+internal sealed class TlsControlConnection : IAsyncDisposable
+{
+    internal const int MaximumPayloadLength = 65536;
+    private readonly Socket socket;
+    private readonly TlsSession tls;
+    private readonly CancellationTokenSource lifetime;
+    private readonly Channel<byte[]> outgoing = System.Threading.Channels.Channel.CreateBounded<byte[]>(64);
+    private readonly Channel<Envelope> incoming = System.Threading.Channels.Channel.CreateBounded<Envelope>(32);
+    private readonly byte[] prefix = new byte[4];
+    private int prefixBytes;
+    private byte[]? payload;
+    private int payloadBytes;
+
+    public Task Completion { get; }
+    public CancellationToken CancellationToken => lifetime.Token;
+
+    internal TlsControlConnection(Socket socket, TlsSession tls, CancellationToken cancellationToken)
+    {
+        this.socket = socket;
+        this.tls = tls;
+        lifetime = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken);
+        lifetime.CancelAfter(TimeSpan.FromSeconds(15));
+        Completion = RunAsync();
+    }
+
+    public IAsyncEnumerable<Envelope> ReadAsync(CancellationToken cancellationToken) => incoming.Reader.ReadAllAsync(cancellationToken);
+
+    public bool TrySend(Envelope envelope)
+    {
+        if (envelope.CalculateSize() > MaximumPayloadLength) throw new InvalidDataException("Server control payload exceeds 64 KiB.");
+        var framed = new ArrayBufferWriter<byte>();
+        ControlFraming.WriteEnvelope(framed, envelope);
+        if (outgoing.Writer.TryWrite(framed.WrittenSpan.ToArray())) return true;
+        lifetime.Cancel();
+        return false;
+    }
+
+    public void CompleteWrites() => outgoing.Writer.TryComplete();
+
+    private async Task RunAsync()
+    {
+        byte[] ciphertext = new byte[16384];
+        byte[] plaintext = new byte[16384];
+        byte[] sendBuffer = new byte[16384];
+        CancellationToken cancellationToken = lifetime.Token;
+        Task<int>? receive = null;
+        Task<bool>? ready = null;
+        Exception? error = null;
+        try
+        {
+            await FlushAsync(sendBuffer, cancellationToken).ConfigureAwait(false);
+            receive = socket.ReceiveAsync(ciphertext, SocketFlags.None, cancellationToken).AsTask();
+            while (true)
+            {
+                if (tls.IsReady)
+                {
+                    while (outgoing.Reader.TryRead(out byte[]? frame)) tls.WritePlaintext(frame);
+                    await FlushAsync(sendBuffer, cancellationToken).ConfigureAwait(false);
+                    ready ??= outgoing.Reader.WaitToReadAsync(cancellationToken).AsTask();
+                }
+                Task winner = ready is null ? receive : await Task.WhenAny(receive, ready).ConfigureAwait(false);
+                if (winner == receive)
+                {
+                    int count = await receive.ConfigureAwait(false);
+                    if (count == 0)
+                    {
+                        tls.CompleteInput();
+                        if (prefixBytes != 0 || payload is not null) throw new InvalidDataException("Truncated control frame.");
+                        break;
+                    }
+                    tls.ReceiveCiphertext(ciphertext.AsSpan(0, count));
+                    if (tls.IsReady) lifetime.CancelAfter(TimeSpan.FromSeconds(60));
+                    while ((count = tls.ReadPlaintext(plaintext)) > 0) Parse(plaintext.AsSpan(0, count));
+                    await FlushAsync(sendBuffer, cancellationToken).ConfigureAwait(false);
+                    receive = socket.ReceiveAsync(ciphertext, SocketFlags.None, cancellationToken).AsTask();
+                }
+                else
+                {
+                    bool hasOutgoing = await ready!.ConfigureAwait(false);
+                    ready = null;
+                    if (!hasOutgoing)
+                    {
+                        tls.Close();
+                        await FlushAsync(sendBuffer, cancellationToken).ConfigureAwait(false);
+                        break;
+                    }
+                }
+            }
+        }
+        catch (Exception exception) when (exception is IOException or SocketException or OperationCanceledException or ObjectDisposedException)
+        {
+            if (!cancellationToken.IsCancellationRequested) error = exception;
+        }
+        finally
+        {
+            lifetime.Cancel();
+            socket.Dispose();
+            if (receive is not null)
+            {
+                try { await receive.ConfigureAwait(false); }
+                catch (Exception exception) when (exception is SocketException or OperationCanceledException or ObjectDisposedException) { }
+            }
+            tls.Dispose();
+            incoming.Writer.TryComplete(error);
+            outgoing.Writer.TryComplete(error);
+        }
+    }
+
+    private async Task FlushAsync(byte[] buffer, CancellationToken cancellationToken)
+    {
+        int count;
+        while ((count = tls.DrainCiphertext(buffer)) > 0)
+        {
+            int sent = 0;
+            while (sent < count)
+            {
+                int written = await socket.SendAsync(buffer.AsMemory(sent, count - sent), SocketFlags.None, cancellationToken).ConfigureAwait(false);
+                if (written == 0) throw new IOException("Socket closed during TLS send.");
+                sent += written;
+            }
+        }
+    }
+
+    private void Parse(ReadOnlySpan<byte> input)
+    {
+        while (!input.IsEmpty)
+        {
+            if (payload is null)
+            {
+                int count = Math.Min(4 - prefixBytes, input.Length);
+                input[..count].CopyTo(prefix.AsSpan(prefixBytes));
+                prefixBytes += count;
+                input = input[count..];
+                if (prefixBytes != 4) continue;
+                uint length = BinaryPrimitives.ReadUInt32BigEndian(prefix);
+                if (length > MaximumPayloadLength) throw new InvalidDataException("Server control payload exceeds 64 KiB.");
+                payload = new byte[length];
+                prefixBytes = 0;
+            }
+            int consumed = Math.Min(payload.Length - payloadBytes, input.Length);
+            input[..consumed].CopyTo(payload.AsSpan(payloadBytes));
+            payloadBytes += consumed;
+            input = input[consumed..];
+            if (payloadBytes != payload.Length) continue;
+            Envelope envelope = Envelope.Parser.ParseFrom(payload);
+            payload = null;
+            payloadBytes = 0;
+            if (!incoming.Writer.TryWrite(envelope)) throw new IOException("Control consumer exceeded its bounded queue.");
+        }
+    }
+
+    public async ValueTask DisposeAsync()
+    {
+        lifetime.Cancel();
+        await Completion.ConfigureAwait(false);
+        lifetime.Dispose();
+    }
+}