using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Net.Sockets;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using MediaBrowser.Common.Net;
using MediaBrowser.Model.Net;
using Microsoft.Extensions.Logging;
namespace Rssdp.Infrastructure
{
/// <summary>
/// Provides the platform independent logic for publishing device existence and responding to search requests.
/// </summary>
public sealed class SsdpCommunicationsServer : DisposableManagedObjectBase, ISsdpCommunicationsServer
{
/* 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 group of sockets to listen for/receive notifications and search requests (_MulticastListenSockets).
* We use a second group, bound to a different local port, to send search requests and listen for
* responses (_SendSockets). The responses are sent to the local ports these sockets are bound to,
* which aren'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 List<Socket> _MulticastListenSockets;
private object _SendSocketSynchroniser = new object();
private List<Socket> _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;
/// <summary>
/// Raised when a HTTPU request message is received by a socket (unicast or multicast).
/// </summary>
public event EventHandler<RequestReceivedEventArgs> RequestReceived;
/// <summary>
/// Raised when an HTTPU response message is received by a socket (unicast or multicast).
/// </summary>
public event EventHandler<ResponseReceivedEventArgs> ResponseReceived;
/// <summary>
/// Minimum constructor.
/// </summary>
/// <exception cref="ArgumentNullException">The <paramref name="socketFactory"/> argument is null.</exception>
public SsdpCommunicationsServer(ISocketFactory socketFactory,
INetworkManager networkManager, ILogger logger, bool enableMultiSocketBinding)
: this(socketFactory, 0, SsdpConstants.SsdpDefaultMulticastTimeToLive, networkManager, logger, enableMultiSocketBinding)
{
}
/// <summary>
/// Full constructor.
/// </summary>
/// <exception cref="ArgumentNullException">The <paramref name="socketFactory"/> argument is null.</exception>
/// <exception cref="ArgumentOutOfRangeException">The <paramref name="multicastTimeToLive"/> argument is less than or equal to zero.</exception>
public SsdpCommunicationsServer(ISocketFactory socketFactory, int localPort, int multicastTimeToLive, INetworkManager networkManager, ILogger logger, bool enableMultiSocketBinding)
{
if (socketFactory is 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;
}
/// <summary>
/// Causes the server to begin listening for multicast messages, being SSDP search requests and notifications.
/// </summary>
/// <exception cref="ObjectDisposedException">Thrown if the <see cref="DisposableManagedObjectBase.IsDisposed"/> property is true (because <seealso cref="DisposableManagedObjectBase.Dispose()" /> has been called previously).</exception>
public void BeginListeningForMulticast()
{
ThrowIfDisposed();
lock (_BroadcastListenSocketSynchroniser)
{
if (_MulticastListenSockets is null)
{
try
{
_MulticastListenSockets = CreateMulticastSocketsAndListen();
}
catch (SocketException ex)
{
_logger.LogError("Failed to bind to multicast address: {Message}. DLNA will be unavailable", ex.Message);
}
catch (Exception ex)
{
_logger.LogError(ex, "Error in BeginListeningForMulticast");
}
}
}
}
/// <summary>
/// Causes the server to stop listening for multicast messages, being SSDP search requests and notifications.
/// </summary>
/// <exception cref="ObjectDisposedException">Thrown if the <see cref="DisposableManagedObjectBase.IsDisposed"/> property is true (because <seealso cref="DisposableManagedObjectBase.Dispose()" /> has been called previously).</exception>
public void StopListeningForMulticast()
{
lock (_BroadcastListenSocketSynchroniser)
{
if (_MulticastListenSockets is not null)
{
_logger.LogInformation("{0} disposing _BroadcastListenSocket", GetType().Name);
foreach (var socket in _MulticastListenSockets)
{
socket.Dispose();
}
_MulticastListenSockets = null;
}
}
}
/// <summary>
/// Sends a message to a particular address (uni or multicast) and port.
/// </summary>
public async Task SendMessage(byte[] messageData, IPEndPoint destination, IPAddress fromlocalIPAddress, CancellationToken cancellationToken)
{
if (messageData is 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(Socket socket, byte[] messageData, IPEndPoint destination, CancellationToken cancellationToken)
{
try
{
await socket.SendToAsync(messageData, destination, cancellationToken).ConfigureAwait(false);
}
catch (ObjectDisposedException)
{
}
catch (OperationCanceledException)
{
}
catch (Exception ex)
{
var localIP = ((IPEndPoint)socket.LocalEndPoint).Address;
_logger.LogError(ex, "Error sending socket message from {0} to {1}", localIP.ToString(), destination.ToString());
}
}
private List<Socket> GetSendSockets(IPAddress fromlocalIPAddress, IPEndPoint destination)
{
EnsureSendSocketCreated();
lock (_SendSocketSynchroniser)
{
var sockets = _sendSockets.Where(s => s.AddressFamily == fromlocalIPAddress.AddressFamily);
// Send from the Any socket and the socket with the matching address
if (fromlocalIPAddress.AddressFamily == AddressFamily.InterNetwork)
{
sockets = sockets.Where(s => ((IPEndPoint)s.LocalEndPoint).Address.Equals(IPAddress.Any)
|| ((IPEndPoint)s.LocalEndPoint).Address.Equals(fromlocalIPAddress));
// If sending to the loopback address, filter the socket list as well
if (destination.Address.Equals(IPAddress.Loopback))
{
sockets = sockets.Where(s => ((IPEndPoint)s.LocalEndPoint).Address.Equals(IPAddress.Any)
|| ((IPEndPoint)s.LocalEndPoint).Address.Equals(IPAddress.Loopback));
}
}
else if (fromlocalIPAddress.AddressFamily == AddressFamily.InterNetworkV6)
{
sockets = sockets.Where(s => ((IPEndPoint)s.LocalEndPoint).Address.Equals(IPAddress.IPv6Any)
|| ((IPEndPoint)s.LocalEndPoint).Address.Equals(fromlocalIPAddress));
// If sending to the loopback address, filter the socket list as well
if (destination.Address.Equals(IPAddress.IPv6Loopback))
{
sockets = sockets.Where(s => ((IPEndPoint)s.LocalEndPoint).Address.Equals(IPAddress.IPv6Any)
|| ((IPEndPoint)s.LocalEndPoint).Address.Equals(IPAddress.IPv6Loopback));
}
}
return sockets.ToList();
}
}
public Task SendMulticastMessage(string message, IPAddress fromlocalIPAddress, CancellationToken cancellationToken)
{
return SendMulticastMessage(message, SsdpConstants.UdpResendCount, fromlocalIPAddress, cancellationToken);
}
/// <summary>
/// Sends a message to the SSDP multicast address and port.
/// </summary>
public async Task SendMulticastMessage(string message, int sendCount, IPAddress fromlocalIPAddress, CancellationToken cancellationToken)
{
if (message is 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 IPEndPoint(
IPAddress.Parse(SsdpConstants.MulticastLocalAdminAddress),
SsdpConstants.MulticastPort),
fromlocalIPAddress,
cancellationToken).ConfigureAwait(false);
await Task.Delay(100, cancellationToken).ConfigureAwait(false);
}
}
/// <summary>
/// Stops listening for search responses on the local, unicast socket.
/// </summary>
/// <exception cref="ObjectDisposedException">Thrown if the <see cref="DisposableManagedObjectBase.IsDisposed"/> property is true (because <seealso cref="DisposableManagedObjectBase.Dispose()" /> has been called previously).</exception>
public void StopListeningForResponses()
{
lock (_SendSocketSynchroniser)
{
if (_sendSockets is not null)
{
var sockets = _sendSockets.ToList();
_sendSockets = null;
_logger.LogInformation("{0} Disposing {1} sendSockets", GetType().Name, sockets.Count);
foreach (var socket in sockets)
{
var socketAddress = ((IPEndPoint)socket.LocalEndPoint).Address;
_logger.LogInformation("{0} disposing sendSocket from {1}", GetType().Name, socketAddress);
socket.Dispose();
}
}
}
}
/// <summary>
/// Gets or sets a boolean value indicating whether or not this instance is shared amongst multiple <see cref="SsdpDeviceLocator"/> and/or <see cref="ISsdpDevicePublisher"/> instances.
/// </summary>
/// <remarks>
/// <para>If true, disposing an instance of a <see cref="SsdpDeviceLocator"/>or a <see cref="ISsdpDevicePublisher"/> will not dispose this comms server instance. The calling code is responsible for managing the lifetime of the server.</para>
/// </remarks>
public bool IsShared
{
get { return _IsShared; }
set { _IsShared = value; }
}
/// <summary>
/// Stops listening for requests, disposes this instance and all internal resources.
/// </summary>
/// <param name="disposing"></param>
protected override void Dispose(bool disposing)
{
if (disposing)
{
StopListeningForMulticast();
StopListeningForResponses();
}
}
private Task SendMessageIfSocketNotDisposed(byte[] messageData, IPEndPoint destination, IPAddress fromlocalIPAddress, CancellationToken cancellationToken)
{
var sockets = _sendSockets;
if (sockets is not null)
{
sockets = sockets.ToList();
var tasks = sockets.Where(s => (fromlocalIPAddress is null || fromlocalIPAddress.Equals(((IPEndPoint)s.LocalEndPoint).Address)))
.Select(s => SendFromSocket(s, messageData, destination, cancellationToken));
return Task.WhenAll(tasks);
}
return Task.CompletedTask;
}
private List<Socket> CreateMulticastSocketsAndListen()
{
var sockets = new List<Socket>();
var multicastGroupAddress = IPAddress.Parse(SsdpConstants.MulticastLocalAdminAddress);
if (_enableMultiSocketBinding)
{
// IPv6 is currently unsupported
var validInterfaces = _networkManager.GetInternalBindAddresses()
.Where(x => x.Address is not null)
.Where(x => x.AddressFamily == AddressFamily.InterNetwork)
.DistinctBy(x => x.Index);
foreach (var intf in validInterfaces)
{
try
{
var socket = _SocketFactory.CreateUdpMulticastSocket(multicastGroupAddress, intf, _MulticastTtl, SsdpConstants.MulticastPort);
_ = ListenToSocketInternal(socket);
sockets.Add(socket);
}
catch (Exception ex)
{
_logger.LogError(ex, "Error in CreateMulticastSocketsAndListen. IP address: {0}", intf.Address);
}
}
}
else
{
var socket = _SocketFactory.CreateUdpMulticastSocket(multicastGroupAddress, new IPData(IPAddress.Any, null), _MulticastTtl, SsdpConstants.MulticastPort);
_ = ListenToSocketInternal(socket);
sockets.Add(socket);
}
return sockets;
}
private List<Socket> CreateSendSockets()
{
var sockets = new List<Socket>();
if (_enableMultiSocketBinding)
{
// IPv6 is currently unsupported
var validInterfaces = _networkManager.GetInternalBindAddresses()
.Where(x => x.Address is not null)
.Where(x => x.AddressFamily == AddressFamily.InterNetwork);
foreach (var intf in validInterfaces)
{
try
{
var socket = _SocketFactory.CreateSsdpUdpSocket(intf, _LocalPort);
_ = ListenToSocketInternal(socket);
sockets.Add(socket);
}
catch (Exception ex)
{
_logger.LogError(ex, "Error in CreateSsdpUdpSocket. IPAddress: {0}", intf.Address);
}
}
}
else
{
var socket = _SocketFactory.CreateSsdpUdpSocket(new IPData(IPAddress.Any, null), _LocalPort);
_ = ListenToSocketInternal(socket);
sockets.Add(socket);
}
return sockets;
}
private async Task ListenToSocketInternal(Socket socket)
{
var cancelled = false;
var receiveBuffer = new byte[8192];
while (!cancelled && !IsDisposed)
{
try
{
var result = await socket.ReceiveMessageFromAsync(receiveBuffer, SocketFlags.None, new IPEndPoint(IPAddress.Any, 0), CancellationToken.None).ConfigureAwait(false);;
if (result.ReceivedBytes > 0)
{
var remoteEndpoint = (IPEndPoint)result.RemoteEndPoint;
var localEndpointAdapter = _networkManager.GetAllBindInterfaces().First(a => a.Index == result.PacketInformation.Interface);
ProcessMessage(
UTF8Encoding.UTF8.GetString(receiveBuffer, 0, result.ReceivedBytes),
remoteEndpoint,
localEndpointAdapter.Address);
}
}
catch (ObjectDisposedException)
{
cancelled = true;
}
catch (TaskCanceledException)
{
cancelled = true;
}
}
}
private void EnsureSendSocketCreated()
{
if (_sendSockets is null)
{
lock (_SendSocketSynchroniser)
{
_sendSockets ??= CreateSendSockets();
}
}
}
private void ProcessMessage(string data, IPEndPoint endPoint, IPAddress 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.
_logger.LogDebug("Received data from {From} on {Port} at {Address}:\n{Data}", endPoint.Address, endPoint.Port, receivedOnlocalIPAddress, data);
if (data.StartsWith("HTTP/", StringComparison.OrdinalIgnoreCase))
{
HttpResponseMessage responseMessage = null;
try
{
responseMessage = _ResponseParser.Parse(data);
}
catch (ArgumentException)
{
// Ignore invalid packets.
}
if (responseMessage is not null)
{
OnResponseReceived(responseMessage, endPoint, receivedOnlocalIPAddress);
}
}
else
{
HttpRequestMessage requestMessage = null;
try
{
requestMessage = _RequestParser.Parse(data);
}
catch (ArgumentException)
{
// Ignore invalid packets.
}
if (requestMessage is not null)
{
OnRequestReceived(requestMessage, endPoint, receivedOnlocalIPAddress);
}
}
}
private void OnRequestReceived(HttpRequestMessage data, IPEndPoint remoteEndPoint, IPAddress 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 is not null)
{
handlers(this, new RequestReceivedEventArgs(data, remoteEndPoint, receivedOnlocalIPAddress));
}
}
private void OnResponseReceived(HttpResponseMessage data, IPEndPoint endPoint, IPAddress localIPAddress)
{
var handlers = this.ResponseReceived;
if (handlers is not null)
{
handlers(this, new ResponseReceivedEventArgs(data, endPoint)
{
LocalIPAddress = localIPAddress
});
}
}
}
}