69 lines
2.2 KiB
C#
69 lines
2.2 KiB
C#
using System.Buffers;
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using System.Buffers.Binary;
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using System.Net;
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using System.Net.Sockets;
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using KcpSharp;
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using Microsoft.Extensions.Logging;
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namespace GameServer.Network.Kcp;
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internal class KcpGateway
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{
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private const int KcpSynPacketSize = 1;
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private const int KcpAckPacketSize = 5;
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private const byte NetFlagSyn = 0xED;
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private const byte NetFlagAck = 0xEE;
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private readonly ILogger _logger;
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private readonly SessionManager _sessionManager;
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private IKcpTransport<IKcpMultiplexConnection>? _kcpTransport;
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private int _convCounter;
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public KcpGateway(ILogger<KcpGateway> logger, SessionManager sessionManager)
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{
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_logger = logger;
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_sessionManager = sessionManager;
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}
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public void Start()
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{
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IPEndPoint endPoint = new(IPAddress.Any, 1337);
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_kcpTransport = KcpSocketTransport.CreateMultiplexConnection(new(endPoint), 1400);
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_kcpTransport.SetHandshakeHandler(KcpSynPacketSize, HandleKcpSynPacket);
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_kcpTransport.Start();
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_logger.LogInformation("Listening for incoming connections at {endPoint}", endPoint);
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}
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private async ValueTask HandleKcpSynPacket(UdpReceiveResult recvResult)
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{
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if (recvResult.Buffer[0] != NetFlagSyn) return;
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_logger.LogInformation("Received SYN from {remoteEndPoint}", recvResult.RemoteEndPoint);
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int conv = Interlocked.Increment(ref _convCounter);
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_ = _sessionManager.RunSessionAsync(_kcpTransport!.Connection.CreateConversation(conv, recvResult.RemoteEndPoint));
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await SendAckAsync(conv, recvResult.RemoteEndPoint);
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}
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private async ValueTask SendAckAsync(int conv, IPEndPoint remoteEndPoint)
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{
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_logger.LogInformation("Sending ACK to {remoteEndPoint}, convID: {conv}", remoteEndPoint, conv);
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byte[] buffer = ArrayPool<byte>.Shared.Rent(KcpAckPacketSize);
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try
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{
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buffer[0] = NetFlagAck;
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BinaryPrimitives.WriteInt32LittleEndian(buffer.AsSpan(1), conv);
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await _kcpTransport!.SendPacketAsync(buffer.AsMemory(0, KcpAckPacketSize), remoteEndPoint, CancellationToken.None);
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}
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finally
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{
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ArrayPool<byte>.Shared.Return(buffer);
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}
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}
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}
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