Move UdpServerEntryPoint to Jellyfin.Networking

2 files changed, 281 insertions, 0 deletions

diff --git a/src/Jellyfin.Networking/Udp/UdpServer.cs b/src/Jellyfin.Networking/Udp/UdpServer.cs
new file mode 100644
index 000000000..978eb7853
--- /dev/null
+++ b/src/Jellyfin.Networking/Udp/UdpServer.cs
@@ -0,0 +1,137 @@
+using System;
+using System.Net;
+using System.Net.Sockets;
+using System.Text;
+using System.Text.Json;
+using System.Threading;
+using System.Threading.Tasks;
+using MediaBrowser.Controller;
+using MediaBrowser.Model.ApiClient;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.Logging;
+using static MediaBrowser.Controller.Extensions.ConfigurationExtensions;
+
+namespace Jellyfin.Networking.Udp
+{
+    /// <summary>
+    /// Provides a Udp Server.
+    /// </summary>
+    public sealed class UdpServer : IDisposable
+    {
+        /// <summary>
+        /// The _logger.
+        /// </summary>
+        private readonly ILogger _logger;
+        private readonly IServerApplicationHost _appHost;
+        private readonly IConfiguration _config;
+
+        private readonly byte[] _receiveBuffer = new byte[8192];
+
+        private readonly Socket _udpSocket;
+        private readonly IPEndPoint _endpoint;
+        private bool _disposed;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="UdpServer" /> class.
+        /// </summary>
+        /// <param name="logger">The logger.</param>
+        /// <param name="appHost">The application host.</param>
+        /// <param name="configuration">The configuration manager.</param>
+        /// <param name="bindAddress"> The bind address.</param>
+        /// <param name="port">The port.</param>
+        public UdpServer(
+            ILogger logger,
+            IServerApplicationHost appHost,
+            IConfiguration configuration,
+            IPAddress bindAddress,
+            int port)
+        {
+            _logger = logger;
+            _appHost = appHost;
+            _config = configuration;
+
+            _endpoint = new IPEndPoint(bindAddress, port);
+
+            _udpSocket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp)
+            {
+                MulticastLoopback = false,
+            };
+            _udpSocket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
+        }
+
+        private async Task RespondToV2Message(EndPoint endpoint, CancellationToken cancellationToken)
+        {
+            string? localUrl = _config[AddressOverrideKey];
+            if (string.IsNullOrEmpty(localUrl))
+            {
+                localUrl = _appHost.GetSmartApiUrl(((IPEndPoint)endpoint).Address);
+            }
+
+            if (string.IsNullOrEmpty(localUrl))
+            {
+                _logger.LogWarning("Unable to respond to server discovery request because the local ip address could not be determined.");
+                return;
+            }
+
+            var response = new ServerDiscoveryInfo(localUrl, _appHost.SystemId, _appHost.FriendlyName);
+
+            try
+            {
+                _logger.LogDebug("Sending AutoDiscovery response");
+                await _udpSocket.SendToAsync(JsonSerializer.SerializeToUtf8Bytes(response), SocketFlags.None, endpoint, cancellationToken).ConfigureAwait(false);
+            }
+            catch (SocketException ex)
+            {
+                _logger.LogError(ex, "Error sending response message");
+            }
+        }
+
+        /// <summary>
+        /// Starts the specified port.
+        /// </summary>
+        /// <param name="cancellationToken">The cancellation token to cancel operation.</param>
+        public void Start(CancellationToken cancellationToken)
+        {
+            _udpSocket.Bind(_endpoint);
+
+            _ = Task.Run(async () => await BeginReceiveAsync(cancellationToken).ConfigureAwait(false), cancellationToken).ConfigureAwait(false);
+        }
+
+        private async Task BeginReceiveAsync(CancellationToken cancellationToken)
+        {
+            while (!cancellationToken.IsCancellationRequested)
+            {
+                try
+                {
+                    var endpoint = (EndPoint)new IPEndPoint(IPAddress.Any, 0);
+                    var result = await _udpSocket.ReceiveFromAsync(_receiveBuffer, endpoint, cancellationToken).ConfigureAwait(false);
+                    var text = Encoding.UTF8.GetString(_receiveBuffer, 0, result.ReceivedBytes);
+                    if (text.Contains("who is JellyfinServer?", StringComparison.OrdinalIgnoreCase))
+                    {
+                        await RespondToV2Message(result.RemoteEndPoint, cancellationToken).ConfigureAwait(false);
+                    }
+                }
+                catch (SocketException ex)
+                {
+                    _logger.LogError(ex, "Failed to receive data from socket");
+                }
+                catch (OperationCanceledException)
+                {
+                    _logger.LogDebug("Broadcast socket operation cancelled");
+                }
+            }
+        }
+
+        /// <inheritdoc />
+        public void Dispose()
+        {
+            if (_disposed)
+            {
+                return;
+            }
+
+            _udpSocket.Dispose();
+            _disposed = true;
+        }
+    }
+}
diff --git a/src/Jellyfin.Networking/UdpServerEntryPoint.cs b/src/Jellyfin.Networking/UdpServerEntryPoint.cs
new file mode 100644
index 000000000..ced5a5ce1
--- /dev/null
+++ b/src/Jellyfin.Networking/UdpServerEntryPoint.cs
@@ -0,0 +1,144 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Net;
+using System.Net.Sockets;
+using System.Threading;
+using System.Threading.Tasks;
+using Jellyfin.Networking.Udp;
+using MediaBrowser.Common.Net;
+using MediaBrowser.Controller;
+using MediaBrowser.Controller.Plugins;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.Logging;
+using IConfigurationManager = MediaBrowser.Common.Configuration.IConfigurationManager;
+
+namespace Jellyfin.Networking
+{
+    /// <summary>
+    /// Class responsible for registering all UDP broadcast endpoints and their handlers.
+    /// </summary>
+    public sealed class UdpServerEntryPoint : IServerEntryPoint
+    {
+        /// <summary>
+        /// The port of the UDP server.
+        /// </summary>
+        public const int PortNumber = 7359;
+
+        /// <summary>
+        /// The logger.
+        /// </summary>
+        private readonly ILogger<UdpServerEntryPoint> _logger;
+        private readonly IServerApplicationHost _appHost;
+        private readonly IConfiguration _config;
+        private readonly IConfigurationManager _configurationManager;
+        private readonly INetworkManager _networkManager;
+
+        /// <summary>
+        /// The UDP server.
+        /// </summary>
+        private readonly List<UdpServer> _udpServers;
+        private readonly CancellationTokenSource _cancellationTokenSource = new CancellationTokenSource();
+        private bool _disposed;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="UdpServerEntryPoint" /> class.
+        /// </summary>
+        /// <param name="logger">Instance of the <see cref="ILogger{UdpServerEntryPoint}"/> interface.</param>
+        /// <param name="appHost">Instance of the <see cref="IServerApplicationHost"/> interface.</param>
+        /// <param name="configuration">Instance of the <see cref="IConfiguration"/> interface.</param>
+        /// <param name="configurationManager">Instance of the <see cref="IConfigurationManager"/> interface.</param>
+        /// <param name="networkManager">Instance of the <see cref="INetworkManager"/> interface.</param>
+        public UdpServerEntryPoint(
+            ILogger<UdpServerEntryPoint> logger,
+            IServerApplicationHost appHost,
+            IConfiguration configuration,
+            IConfigurationManager configurationManager,
+            INetworkManager networkManager)
+        {
+            _logger = logger;
+            _appHost = appHost;
+            _config = configuration;
+            _configurationManager = configurationManager;
+            _networkManager = networkManager;
+            _udpServers = new List<UdpServer>();
+        }
+
+        /// <inheritdoc />
+        public Task RunAsync()
+        {
+            ObjectDisposedException.ThrowIf(_disposed, this);
+
+            if (!_configurationManager.GetNetworkConfiguration().AutoDiscovery)
+            {
+                return Task.CompletedTask;
+            }
+
+            try
+            {
+                // Linux needs to bind to the broadcast addresses to get broadcast traffic
+                // Windows receives broadcast fine when binding to just the interface, it is unable to bind to broadcast addresses
+                if (OperatingSystem.IsLinux())
+                {
+                    // Add global broadcast listener
+                    var server = new UdpServer(_logger, _appHost, _config, IPAddress.Broadcast, PortNumber);
+                    server.Start(_cancellationTokenSource.Token);
+                    _udpServers.Add(server);
+
+                    // Add bind address specific broadcast listeners
+                    // IPv6 is currently unsupported
+                    var validInterfaces = _networkManager.GetInternalBindAddresses().Where(i => i.AddressFamily == AddressFamily.InterNetwork);
+                    foreach (var intf in validInterfaces)
+                    {
+                        var broadcastAddress = NetworkUtils.GetBroadcastAddress(intf.Subnet);
+                        _logger.LogDebug("Binding UDP server to {Address} on port {PortNumber}", broadcastAddress, PortNumber);
+
+                        server = new UdpServer(_logger, _appHost, _config, broadcastAddress, PortNumber);
+                        server.Start(_cancellationTokenSource.Token);
+                        _udpServers.Add(server);
+                    }
+                }
+                else
+                {
+                    // Add bind address specific broadcast listeners
+                    // IPv6 is currently unsupported
+                    var validInterfaces = _networkManager.GetInternalBindAddresses().Where(i => i.AddressFamily == AddressFamily.InterNetwork);
+                    foreach (var intf in validInterfaces)
+                    {
+                        var intfAddress = intf.Address;
+                        _logger.LogDebug("Binding UDP server to {Address} on port {PortNumber}", intfAddress, PortNumber);
+
+                        var server = new UdpServer(_logger, _appHost, _config, intfAddress, PortNumber);
+                        server.Start(_cancellationTokenSource.Token);
+                        _udpServers.Add(server);
+                    }
+                }
+            }
+            catch (SocketException ex)
+            {
+                _logger.LogWarning(ex, "Unable to start AutoDiscovery listener on UDP port {PortNumber}", PortNumber);
+            }
+
+            return Task.CompletedTask;
+        }
+
+        /// <inheritdoc />
+        public void Dispose()
+        {
+            if (_disposed)
+            {
+                return;
+            }
+
+            _cancellationTokenSource.Cancel();
+            _cancellationTokenSource.Dispose();
+            foreach (var server in _udpServers)
+            {
+                server.Dispose();
+            }
+
+            _udpServers.Clear();
+            _disposed = true;
+        }
+    }
+}