using System; using System.Collections.Generic; using System.Linq; using System.Net; using System.Net.Http; using System.Text; using System.Threading; using System.Threading.Tasks; using MediaBrowser.Common.Net; using Microsoft.Extensions.Logging; using MediaBrowser.Model.Net; namespace Rssdp.Infrastructure { /// /// Provides the platform independent logic for publishing device existence and responding to search requests. /// public sealed class SsdpCommunicationsServer : DisposableManagedObjectBase, ISsdpCommunicationsServer { #region Fields /* We could technically use one socket listening on port 1900 for everything. * This should get both multicast (notifications) and unicast (search response) messages, however * this often doesn't work under Windows because the MS SSDP service is running. If that service * is running then it will steal the unicast messages and we will never see search responses. * Since stopping the service would be a bad idea (might not be allowed security wise and might * break other apps running on the system) the only other work around is to use two sockets. * * We use one socket to listen for/receive notifications and search requests (_BroadcastListenSocket). * We use a second socket, bound to a different local port, to send search requests and listen for * responses (_SendSocket). The responses are sent to the local port this socket is bound to, * which isn't port 1900 so the MS service doesn't steal them. While the caller can specify a local * port to use, we will default to 0 which allows the underlying system to auto-assign a free port. */ private object _BroadcastListenSocketSynchroniser = new object(); private ISocket _BroadcastListenSocket; private object _SendSocketSynchroniser = new object(); private List _sendSockets; private HttpRequestParser _RequestParser; private HttpResponseParser _ResponseParser; private readonly ILogger _logger; private ISocketFactory _SocketFactory; private readonly INetworkManager _networkManager; private int _LocalPort; private int _MulticastTtl; private bool _IsShared; private readonly bool _enableMultiSocketBinding; #endregion #region Events /// /// Raised when a HTTPU request message is received by a socket (unicast or multicast). /// public event EventHandler RequestReceived; /// /// Raised when an HTTPU response message is received by a socket (unicast or multicast). /// public event EventHandler ResponseReceived; #endregion #region Constructors /// /// Minimum constructor. /// /// The argument is null. public SsdpCommunicationsServer(ISocketFactory socketFactory, INetworkManager networkManager, ILogger logger, bool enableMultiSocketBinding) : this(socketFactory, 0, SsdpConstants.SsdpDefaultMulticastTimeToLive, networkManager, logger, enableMultiSocketBinding) { } /// /// Full constructor. /// /// The argument is null. /// The argument is less than or equal to zero. public SsdpCommunicationsServer(ISocketFactory socketFactory, int localPort, int multicastTimeToLive, INetworkManager networkManager, ILogger logger, bool enableMultiSocketBinding) { if (socketFactory == null) throw new ArgumentNullException(nameof(socketFactory)); if (multicastTimeToLive <= 0) throw new ArgumentOutOfRangeException(nameof(multicastTimeToLive), "multicastTimeToLive must be greater than zero."); _BroadcastListenSocketSynchroniser = new object(); _SendSocketSynchroniser = new object(); _LocalPort = localPort; _SocketFactory = socketFactory; _RequestParser = new HttpRequestParser(); _ResponseParser = new HttpResponseParser(); _MulticastTtl = multicastTimeToLive; _networkManager = networkManager; _logger = logger; _enableMultiSocketBinding = enableMultiSocketBinding; } #endregion #region Public Methods /// /// Causes the server to begin listening for multicast messages, being SSDP search requests and notifications. /// /// Thrown if the property is true (because has been called previously). public void BeginListeningForBroadcasts() { ThrowIfDisposed(); if (_BroadcastListenSocket == null) { lock (_BroadcastListenSocketSynchroniser) { if (_BroadcastListenSocket == null) { try { _BroadcastListenSocket = ListenForBroadcastsAsync(); } catch (Exception ex) { _logger.LogError(ex, "Error in BeginListeningForBroadcasts"); } } } } } /// /// Causes the server to stop listening for multicast messages, being SSDP search requests and notifications. /// /// Thrown if the property is true (because has been called previously). public void StopListeningForBroadcasts() { lock (_BroadcastListenSocketSynchroniser) { if (_BroadcastListenSocket != null) { _logger.LogInformation("{0} disposing _BroadcastListenSocket.", GetType().Name); _BroadcastListenSocket.Dispose(); _BroadcastListenSocket = null; } } } /// /// Sends a message to a particular address (uni or multicast) and port. /// public async Task SendMessage(byte[] messageData, IpEndPointInfo destination, IpAddressInfo fromLocalIpAddress, CancellationToken cancellationToken) { if (messageData == null) throw new ArgumentNullException(nameof(messageData)); ThrowIfDisposed(); var sockets = GetSendSockets(fromLocalIpAddress, destination); if (sockets.Count == 0) { return; } // SSDP spec recommends sending messages multiple times (not more than 3) to account for possible packet loss over UDP. for (var i = 0; i < SsdpConstants.UdpResendCount; i++) { var tasks = sockets.Select(s => SendFromSocket(s, messageData, destination, cancellationToken)).ToArray(); await Task.WhenAll(tasks).ConfigureAwait(false); await Task.Delay(100, cancellationToken).ConfigureAwait(false); } } private async Task SendFromSocket(ISocket socket, byte[] messageData, IpEndPointInfo destination, CancellationToken cancellationToken) { try { await socket.SendToAsync(messageData, 0, messageData.Length, destination, cancellationToken).ConfigureAwait(false); } catch (ObjectDisposedException) { } catch (OperationCanceledException) { } catch (Exception ex) { _logger.LogError(ex, "Error sending socket message from {0} to {1}", socket.LocalIPAddress.ToString(), destination.ToString()); } } private List GetSendSockets(IpAddressInfo fromLocalIpAddress, IpEndPointInfo destination) { EnsureSendSocketCreated(); lock (_SendSocketSynchroniser) { var sockets = _sendSockets.Where(i => i.LocalIPAddress.AddressFamily == fromLocalIpAddress.AddressFamily); // Send from the Any socket and the socket with the matching address if (fromLocalIpAddress.AddressFamily == IpAddressFamily.InterNetwork) { sockets = sockets.Where(i => i.LocalIPAddress.Equals(IpAddressInfo.Any) || fromLocalIpAddress.Equals(i.LocalIPAddress)); // If sending to the loopback address, filter the socket list as well if (destination.IpAddress.Equals(IpAddressInfo.Loopback)) { sockets = sockets.Where(i => i.LocalIPAddress.Equals(IpAddressInfo.Any) || i.LocalIPAddress.Equals(IpAddressInfo.Loopback)); } } else if (fromLocalIpAddress.AddressFamily == IpAddressFamily.InterNetworkV6) { sockets = sockets.Where(i => i.LocalIPAddress.Equals(IpAddressInfo.IPv6Any) || fromLocalIpAddress.Equals(i.LocalIPAddress)); // If sending to the loopback address, filter the socket list as well if (destination.IpAddress.Equals(IpAddressInfo.IPv6Loopback)) { sockets = sockets.Where(i => i.LocalIPAddress.Equals(IpAddressInfo.IPv6Any) || i.LocalIPAddress.Equals(IpAddressInfo.IPv6Loopback)); } } return sockets.ToList(); } } public Task SendMulticastMessage(string message, CancellationToken cancellationToken) { return SendMulticastMessage(message, SsdpConstants.UdpResendCount, cancellationToken); } /// /// Sends a message to the SSDP multicast address and port. /// public async Task SendMulticastMessage(string message, int sendCount, CancellationToken cancellationToken) { if (message == null) throw new ArgumentNullException(nameof(message)); byte[] messageData = Encoding.UTF8.GetBytes(message); ThrowIfDisposed(); cancellationToken.ThrowIfCancellationRequested(); EnsureSendSocketCreated(); // SSDP spec recommends sending messages multiple times (not more than 3) to account for possible packet loss over UDP. for (var i = 0; i < sendCount; i++) { await SendMessageIfSocketNotDisposed(messageData, new IpEndPointInfo { IpAddress = new IpAddressInfo(SsdpConstants.MulticastLocalAdminAddress, IpAddressFamily.InterNetwork), Port = SsdpConstants.MulticastPort }, cancellationToken).ConfigureAwait(false); await Task.Delay(100, cancellationToken).ConfigureAwait(false); } } /// /// Stops listening for search responses on the local, unicast socket. /// /// Thrown if the property is true (because has been called previously). public void StopListeningForResponses() { lock (_SendSocketSynchroniser) { if (_sendSockets != null) { var sockets = _sendSockets.ToList(); _sendSockets = null; _logger.LogInformation("{0} Disposing {1} sendSockets", GetType().Name, sockets.Count); foreach (var socket in sockets) { _logger.LogInformation("{0} disposing sendSocket from {1}", GetType().Name, socket.LocalIPAddress); socket.Dispose(); } } } } #endregion #region Public Properties /// /// Gets or sets a boolean value indicating whether or not this instance is shared amongst multiple and/or instances. /// /// /// If true, disposing an instance of a or a will not dispose this comms server instance. The calling code is responsible for managing the lifetime of the server. /// public bool IsShared { get { return _IsShared; } set { _IsShared = value; } } #endregion #region Overrides /// /// Stops listening for requests, disposes this instance and all internal resources. /// /// protected override void Dispose(bool disposing) { if (disposing) { StopListeningForBroadcasts(); StopListeningForResponses(); } } #endregion #region Private Methods private Task SendMessageIfSocketNotDisposed(byte[] messageData, IpEndPointInfo destination, CancellationToken cancellationToken) { var sockets = _sendSockets; if (sockets != null) { sockets = sockets.ToList(); var tasks = sockets.Select(s => SendFromSocket(s, messageData, destination, cancellationToken)); return Task.WhenAll(tasks); } return Task.CompletedTask; } private ISocket ListenForBroadcastsAsync() { var socket = _SocketFactory.CreateUdpMulticastSocket(SsdpConstants.MulticastLocalAdminAddress, _MulticastTtl, SsdpConstants.MulticastPort); ListenToSocket(socket); return socket; } private List CreateSocketAndListenForResponsesAsync() { var sockets = new List(); sockets.Add(_SocketFactory.CreateSsdpUdpSocket(IpAddressInfo.Any, _LocalPort)); if (_enableMultiSocketBinding) { foreach (var address in _networkManager.GetLocalIpAddresses()) { if (address.AddressFamily == IpAddressFamily.InterNetworkV6) { // Not supported ? continue; } try { sockets.Add(_SocketFactory.CreateSsdpUdpSocket(address, _LocalPort)); } catch (Exception ex) { _logger.LogError(ex, "Error in CreateSsdpUdpSocket. IPAddress: {0}", address); } } } foreach (var socket in sockets) { ListenToSocket(socket); } return sockets; } [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Performance", "CA1804:RemoveUnusedLocals", MessageId = "t", Justification = "Capturing task to local variable removes compiler warning, task is not otherwise required.")] private void ListenToSocket(ISocket socket) { // Tasks are captured to local variables even if we don't use them just to avoid compiler warnings. var t = Task.Run(() => ListenToSocketInternal(socket)); } private async Task ListenToSocketInternal(ISocket socket) { var cancelled = false; var receiveBuffer = new byte[8192]; while (!cancelled && !IsDisposed) { try { var result = await socket.ReceiveAsync(receiveBuffer, 0, receiveBuffer.Length, CancellationToken.None).ConfigureAwait(false); if (result.ReceivedBytes > 0) { // Strange cannot convert compiler error here if I don't explicitly // assign or cast to Action first. Assignment is easier to read, // so went with that. ProcessMessage(System.Text.UTF8Encoding.UTF8.GetString(result.Buffer, 0, result.ReceivedBytes), result.RemoteEndPoint, result.LocalIPAddress); } } catch (ObjectDisposedException) { cancelled = true; } catch (TaskCanceledException) { cancelled = true; } } } private void EnsureSendSocketCreated() { if (_sendSockets == null) { lock (_SendSocketSynchroniser) { if (_sendSockets == null) { _sendSockets = CreateSocketAndListenForResponsesAsync(); } } } } private void ProcessMessage(string data, IpEndPointInfo endPoint, IpAddressInfo receivedOnLocalIpAddress) { //Responses start with the HTTP version, prefixed with HTTP/ while //requests start with a method which can vary and might be one we haven't //seen/don't know. We'll check if this message is a request or a response //by checking for the HTTP/ prefix on the start of the message. if (data.StartsWith("HTTP/", StringComparison.OrdinalIgnoreCase)) { HttpResponseMessage responseMessage = null; try { responseMessage = _ResponseParser.Parse(data); } catch (ArgumentException) { // Ignore invalid packets. } if (responseMessage != null) OnResponseReceived(responseMessage, endPoint, receivedOnLocalIpAddress); } else { HttpRequestMessage requestMessage = null; try { requestMessage = _RequestParser.Parse(data); } catch (ArgumentException) { // Ignore invalid packets. } if (requestMessage != null) { OnRequestReceived(requestMessage, endPoint, receivedOnLocalIpAddress); } } } private void OnRequestReceived(HttpRequestMessage data, IpEndPointInfo remoteEndPoint, IpAddressInfo receivedOnLocalIpAddress) { //SSDP specification says only * is currently used but other uri's might //be implemented in the future and should be ignored unless understood. //Section 4.2 - http://tools.ietf.org/html/draft-cai-ssdp-v1-03#page-11 if (data.RequestUri.ToString() != "*") { return; } var handlers = this.RequestReceived; if (handlers != null) handlers(this, new RequestReceivedEventArgs(data, remoteEndPoint, receivedOnLocalIpAddress)); } private void OnResponseReceived(HttpResponseMessage data, IpEndPointInfo endPoint, IpAddressInfo localIpAddress) { var handlers = this.ResponseReceived; if (handlers != null) handlers(this, new ResponseReceivedEventArgs(data, endPoint) { LocalIpAddress = localIpAddress }); } #endregion } }