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
}
}