1 files changed, 61 insertions, 0 deletions
diff --git a/src/Agent.Admin/Agent.Admin.Client/AdminProtocol.cs b/src/Agent.Admin/Agent.Admin.Client/AdminProtocol.cs
new file mode 100644
index 0000000..679ccab
--- /dev/null
+++ b/src/Agent.Admin/Agent.Admin.Client/AdminProtocol.cs
@@ -0,0 +1,61 @@
+using System.Buffers.Binary;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace Agent.Admin.Client;
+
+public sealed record AdminNetworkEndpoint(string Address, int Port);
+
+public sealed record AdminRequest(
+    int Version,
+    string Operation,
+    Guid TaskId,
+    string? ApplicationSid = null,
+    string? NetworkAccess = null,
+    IReadOnlyList<AdminNetworkEndpoint>? Endpoints = null,
+    bool? OriginallyLoopbackExempt = null);
+
+public sealed record AdminResponse(bool Success, string? ErrorCode = null, string? Message = null, bool? LoopbackExempt = null);
+
+public static class AdminProtocol
+{
+    public const int Version = 1;
+    public const int MaxMessageBytes = 64 * 1024;
+    private static readonly JsonSerializerOptions Json = new(JsonSerializerDefaults.Web)
+    {
+        UnmappedMemberHandling = JsonUnmappedMemberHandling.Disallow
+    };
+
+    public static async Task WriteAsync<T>(Stream stream, T value, CancellationToken cancellationToken)
+    {
+        byte[] payload = JsonSerializer.SerializeToUtf8Bytes(value, Json);
+        if (payload.Length is <= 0 or > MaxMessageBytes) throw new InvalidDataException("Administrative pipe message exceeds the fixed size limit.");
+        byte[] header = new byte[sizeof(int)];
+        BinaryPrimitives.WriteInt32LittleEndian(header, payload.Length);
+        await stream.WriteAsync(header, cancellationToken).ConfigureAwait(false);
+        await stream.WriteAsync(payload, cancellationToken).ConfigureAwait(false);
+        await stream.FlushAsync(cancellationToken).ConfigureAwait(false);
+    }
+
+    public static async Task<T> ReadAsync<T>(Stream stream, CancellationToken cancellationToken)
+    {
+        byte[] header = new byte[sizeof(int)];
+        await ReadExactlyAsync(stream, header, cancellationToken).ConfigureAwait(false);
+        int length = BinaryPrimitives.ReadInt32LittleEndian(header);
+        if (length is <= 0 or > MaxMessageBytes) throw new InvalidDataException("Administrative pipe message has an invalid size.");
+        byte[] payload = new byte[length];
+        await ReadExactlyAsync(stream, payload, cancellationToken).ConfigureAwait(false);
+        return JsonSerializer.Deserialize<T>(payload, Json) ?? throw new InvalidDataException("Administrative pipe message is empty.");
+    }
+
+    private static async Task ReadExactlyAsync(Stream stream, Memory<byte> buffer, CancellationToken cancellationToken)
+    {
+        int offset = 0;
+        while (offset < buffer.Length)
+        {
+            int read = await stream.ReadAsync(buffer[offset..], cancellationToken).ConfigureAwait(false);
+            if (read == 0) throw new EndOfStreamException("Administrative pipe disconnected.");
+            offset += read;
+        }
+    }
+}