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Diffstat (limited to 'Impostor-dev/src/Impostor.Hazel/Udp/UdpClientConnection.cs')
| -rw-r--r-- | Impostor-dev/src/Impostor.Hazel/Udp/UdpClientConnection.cs | 225 |
1 files changed, 225 insertions, 0 deletions
diff --git a/Impostor-dev/src/Impostor.Hazel/Udp/UdpClientConnection.cs b/Impostor-dev/src/Impostor.Hazel/Udp/UdpClientConnection.cs new file mode 100644 index 0000000..5125ebe --- /dev/null +++ b/Impostor-dev/src/Impostor.Hazel/Udp/UdpClientConnection.cs @@ -0,0 +1,225 @@ +using System; +using System.Buffers; +using System.Net; +using System.Net.Sockets; +using System.Threading; +using System.Threading.Channels; +using System.Threading.Tasks; +using Impostor.Api.Net.Messages; +using Microsoft.Extensions.ObjectPool; +using Serilog; + +namespace Impostor.Hazel.Udp +{ + /// <summary> + /// Represents a client's connection to a server that uses the UDP protocol. + /// </summary> + /// <inheritdoc/> + public sealed class UdpClientConnection : UdpConnection + { + private static readonly ILogger Logger = Log.ForContext<UdpClientConnection>(); + + /// <summary> + /// The socket we're connected via. + /// </summary> + private readonly UdpClient _socket; + + private readonly Timer _reliablePacketTimer; + private readonly SemaphoreSlim _connectWaitLock; + private Task _listenTask; + + /// <summary> + /// Creates a new UdpClientConnection. + /// </summary> + /// <param name="remoteEndPoint">A <see cref="NetworkEndPoint"/> to connect to.</param> + public UdpClientConnection(IPEndPoint remoteEndPoint, ObjectPool<MessageReader> readerPool, IPMode ipMode = IPMode.IPv4) : base(null, readerPool) + { + EndPoint = remoteEndPoint; + RemoteEndPoint = remoteEndPoint; + IPMode = ipMode; + + _socket = new UdpClient + { + DontFragment = false + }; + + _reliablePacketTimer = new Timer(ManageReliablePacketsInternal, null, 100, Timeout.Infinite); + _connectWaitLock = new SemaphoreSlim(1, 1); + } + + ~UdpClientConnection() + { + Dispose(false); + } + + private async void ManageReliablePacketsInternal(object state) + { + await ManageReliablePackets(); + + try + { + _reliablePacketTimer.Change(100, Timeout.Infinite); + } + catch + { + // ignored + } + } + + /// <inheritdoc /> + protected override ValueTask WriteBytesToConnection(byte[] bytes, int length) + { + return WriteBytesToConnectionReal(bytes, length); + } + + private async ValueTask WriteBytesToConnectionReal(byte[] bytes, int length) + { + try + { + await _socket.SendAsync(bytes, length); + } + catch (NullReferenceException) { } + catch (ObjectDisposedException) + { + // Already disposed and disconnected... + } + catch (SocketException ex) + { + await DisconnectInternal(HazelInternalErrors.SocketExceptionSend, "Could not send data as a SocketException occurred: " + ex.Message); + } + } + + /// <inheritdoc /> + public override async ValueTask ConnectAsync(byte[] bytes = null) + { + State = ConnectionState.Connecting; + + try + { + _socket.Connect(RemoteEndPoint); + } + catch (SocketException e) + { + State = ConnectionState.NotConnected; + throw new HazelException("A SocketException occurred while binding to the port.", e); + } + + try + { + _listenTask = Task.Factory.StartNew(ListenAsync, TaskCreationOptions.LongRunning); + } + catch (ObjectDisposedException) + { + // If the socket's been disposed then we can just end there but make sure we're in NotConnected state. + // If we end up here I'm really lost... + State = ConnectionState.NotConnected; + return; + } + catch (SocketException e) + { + Dispose(); + throw new HazelException("A SocketException occurred while initiating a receive operation.", e); + } + + // Write bytes to the server to tell it hi (and to punch a hole in our NAT, if present) + // When acknowledged set the state to connected + await SendHello(bytes, () => + { + State = ConnectionState.Connected; + InitializeKeepAliveTimer(); + }); + + await _connectWaitLock.WaitAsync(TimeSpan.FromSeconds(10)); + } + + private async Task ListenAsync() + { + // Start packet handler. + await StartAsync(); + + // Listen. + while (State != ConnectionState.NotConnected) + { + UdpReceiveResult data; + + try + { + data = await _socket.ReceiveAsync(); + } + catch (SocketException e) + { + await DisconnectInternal(HazelInternalErrors.SocketExceptionReceive, "Socket exception while reading data: " + e.Message); + return; + } + catch (Exception) + { + return; + } + + if (data.Buffer.Length == 0) + { + await DisconnectInternal(HazelInternalErrors.ReceivedZeroBytes, "Received 0 bytes"); + return; + } + + // Write to client. + await Pipeline.Writer.WriteAsync(data.Buffer); + } + } + + protected override void SetState(ConnectionState state) + { + if (state == ConnectionState.Connected) + { + _connectWaitLock.Release(); + } + } + + /// <summary> + /// Sends a disconnect message to the end point. + /// You may include optional disconnect data. The SendOption must be unreliable. + /// </summary> + protected override async ValueTask<bool> SendDisconnect(MessageWriter data = null) + { + lock (this) + { + if (_state == ConnectionState.NotConnected) return false; + _state = ConnectionState.NotConnected; + } + + var bytes = EmptyDisconnectBytes; + if (data != null && data.Length > 0) + { + if (data.SendOption != MessageType.Unreliable) + { + throw new ArgumentException("Disconnect messages can only be unreliable."); + } + + bytes = data.ToByteArray(true); + bytes[0] = (byte)UdpSendOption.Disconnect; + } + + try + { + await _socket.SendAsync(bytes, bytes.Length, RemoteEndPoint); + } + catch { } + + return true; + } + + /// <inheritdoc /> + protected override void Dispose(bool disposing) + { + State = ConnectionState.NotConnected; + + try { _socket.Close(); } catch { } + try { _socket.Dispose(); } catch { } + + _reliablePacketTimer.Dispose(); + _connectWaitLock.Dispose(); + + base.Dispose(disposing); + } + } +} |