313 lines
11 KiB
C#
313 lines
11 KiB
C#
using System;
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using System.Collections.Concurrent;
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using System.Collections.Generic;
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using System.Net;
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using System.Net.Sockets;
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using System.Threading;
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using System.Threading.Tasks;
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namespace Network.NetworkTransport
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{
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internal sealed class LegacyUdpTransportAdapter : ITransport, IPeerSessionTransport
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{
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private readonly UdpClient _client;
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private readonly IPEndPoint? _defaultRemoteEndPoint;
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private readonly bool _isServer;
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private readonly ConcurrentDictionary<string, ClientSession> _sessions = new ConcurrentDictionary<string, ClientSession>();
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private readonly ConcurrentDictionary<Packet, int> _resentPacketTimes = new ConcurrentDictionary<Packet, int>();
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private readonly Timer _retransmitTimer;
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private readonly Timer _cleanupTimer;
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//TODO: volatile 关键字
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private volatile bool _isRunning;
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// 配置参数
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private const int RetransmitTimeoutMs = 1000;
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private const int SessionTimeoutMs = 30000;
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private const int MaxRetransmitAttempts = 5;
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public event Action<byte[], IPEndPoint>? OnReceive;
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// 构造函数——服务端模式
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public LegacyUdpTransportAdapter(int listenPort)
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{
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_client = new UdpClient(listenPort);
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_isServer = true;
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_retransmitTimer = new Timer(CheckRetransmit, null, 100, 100);
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_cleanupTimer = new Timer(CleanupSessions, null, 5000, 5000);
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Console.WriteLine($"[Transport] 服务端模式，监听端口: {listenPort}");
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}
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// 构造函数——客户端模式
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public LegacyUdpTransportAdapter(string serverIP, int serverPort)
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{
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_client = new UdpClient(0);
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_defaultRemoteEndPoint = new IPEndPoint(IPAddress.Parse(serverIP), serverPort);
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_isServer = false;
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_retransmitTimer = new Timer(CheckRetransmit, null, 100, 100);
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_cleanupTimer = new Timer(CleanupSessions, null, 5000, 5000);
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Console.WriteLine($"[Transport] 客户端模式，目标: {_defaultRemoteEndPoint}");
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}
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public async Task StartAsync()
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{
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_sessions.Clear();
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_isRunning = true;
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Console.WriteLine("[Transport] 传输层启动");
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// 开始接收数据
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_ = Task.Run(ReceiveLoop);
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await Task.Delay(100); // 给接收循环一点启动时间
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}
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public void Stop()
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{
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_isRunning = false;
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_retransmitTimer.Dispose();
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_cleanupTimer.Dispose();
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_client.Close();
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_sessions.Clear();
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Console.WriteLine("[Transport] 传输层停止");
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}
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public void Send(byte[] data)
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{
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if (!_isServer && _defaultRemoteEndPoint != null)
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{
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SendTo(data, _defaultRemoteEndPoint);
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}
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else
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{
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throw new InvalidOperationException("服务端模式必须使用 SendTo 指定目标");
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}
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}
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public void SendTo(byte[] data, IPEndPoint target)
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{
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if (!_isRunning)
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{
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return;
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}
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var session = GetOrCreateSession(target);
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uint seqNum = session.GetNextSendSequence();
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var packet = Packet.CreateDataPacket(seqNum, data);
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session.PendingAcks[seqNum] = (packet, DateTime.Now);
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SendPacketTo(packet, target);
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Console.WriteLine($"[Transport] 发送数据包到 {target} SeqNum={seqNum}, DataLen={data.Length}");
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}
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public void SendToAll(byte[] data)
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{
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foreach (var session in _sessions.Values)
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{
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SendTo(data, session.EndPoint);
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}
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}
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public bool RemovePeerSession(IPEndPoint remoteEndPoint)
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{
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if (remoteEndPoint == null)
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{
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throw new ArgumentNullException(nameof(remoteEndPoint));
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}
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return _sessions.TryRemove(remoteEndPoint.ToString(), out _);
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}
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private async void ReceiveLoop()
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{
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while (_isRunning)
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{
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try
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{
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var result = await _client.ReceiveAsync();
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var packet = Packet.FromBytes(result.Buffer);
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if (packet.Type == PacketType.Data)
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{
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HandleDataPacket(packet, result.RemoteEndPoint);
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}
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else if (packet.Type == PacketType.Ack)
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{
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HandleAckPacket(packet, result.RemoteEndPoint);
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}
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}
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catch (ObjectDisposedException)
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{
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return; // 正常关闭
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}
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catch (Exception e)
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{
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Console.WriteLine($"[Transport] 接收错误：{e.Message}");
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}
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}
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}
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private void HandleDataPacket(Packet packet, IPEndPoint senderEndPoint)
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{
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var session = GetOrCreateSession(senderEndPoint);
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Console.WriteLine(
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$"[Transport] 收到数据包从{senderEndPoint} SeqNum={packet.SequenceNumber}, DataLen={packet.Data.Length}");
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// 发送ACK
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var ackPacket = Packet.CreateAckPacket(packet.SequenceNumber);
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SendPacketTo(ackPacket, senderEndPoint);
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Console.WriteLine($"[Transport] 发送ACK 到 {senderEndPoint} SeqNum={packet.SequenceNumber}");
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// 检查是否应该交付
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if (session.TryProcessReceiveSequence(packet.SequenceNumber, out bool shouldDeliver))
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{
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if (shouldDeliver)
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{
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OnReceive?.Invoke(packet.Data, senderEndPoint);
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Console.WriteLine($"[Transport] 交付数据包从 {senderEndPoint} SeqNum={packet.SequenceNumber}");
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}
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else
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{
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Console.WriteLine($"[Transport] 重复包从 {senderEndPoint} SeqNum={packet.SequenceNumber}，忽略");
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}
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}
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else
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{
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// 乱序到达，暂存（简化处理：直接丢弃，依赖重传）
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Console.WriteLine($"[Transport] 乱序包从 {senderEndPoint} SeqNum={packet.SequenceNumber}，丢弃");
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}
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}
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private void HandleAckPacket(Packet packet, IPEndPoint senderEndPoint)
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{
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var session = GetOrCreateSession(senderEndPoint);
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Console.WriteLine($"[Transport] 收到ACK从 {senderEndPoint} SeqNum={packet.SequenceNumber}");
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if (session.PendingAcks.TryRemove(packet.SequenceNumber, out _))
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{
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Console.WriteLine($"[Transport] 确认包到 {senderEndPoint} SeqNum={packet.SequenceNumber}");
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}
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}
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private ClientSession GetOrCreateSession(IPEndPoint endPoint)
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{
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string key = endPoint.ToString();
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return _sessions.GetOrAdd(key, _ =>
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{
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var session = new ClientSession(endPoint);
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Console.WriteLine($"创建新会话：{endPoint}");
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return session;
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});
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}
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private void CheckRetransmit(object? state)
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{
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if (!_isRunning)
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{
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return;
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}
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var now = DateTime.Now;
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var toRetransmit = new List<(IPEndPoint target, uint seqNum, Packet packet)>();
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foreach (var sessionKvp in _sessions)
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{
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var session = sessionKvp.Value;
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foreach (var ackKvp in session.PendingAcks)
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{
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var timeSinceLastSend = now - ackKvp.Value.sendTime;
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if (timeSinceLastSend.TotalMilliseconds > RetransmitTimeoutMs)
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{
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toRetransmit.Add((session.EndPoint, ackKvp.Key, ackKvp.Value.packet));
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_resentPacketTimes.TryAdd(ackKvp.Value.packet, 0);
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}
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}
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}
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foreach (var (target, seqNum, packet) in toRetransmit)
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{
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var session = GetOrCreateSession(target);
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if (session.PendingAcks.ContainsKey(seqNum))
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{
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// 更新发送时间
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session.PendingAcks[seqNum] = (packet, now);
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SendPacketTo(packet, target);
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Console.WriteLine($"[Transport] 重传包到 {target} SeqNum={seqNum}");
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_resentPacketTimes[packet]++;
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if (_resentPacketTimes[packet] >= MaxRetransmitAttempts)
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{
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// 达到最大重传次数，放弃该会话
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Console.WriteLine($"[Transport] 达到最大重传次数，放弃会话 {target}");
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_sessions.TryRemove(target.ToString(), out _);
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}
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}
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}
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}
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private void CleanupSessions(object? state)
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{
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if (!_isRunning)
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{
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return;
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}
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var now = DateTime.Now;
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var toRemove = new List<string>();
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foreach (var sessionKvp in _sessions)
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{
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var session = sessionKvp.Value;
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var timeSinceLastActivity = now - session.LastActivity;
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if (timeSinceLastActivity.TotalMilliseconds > SessionTimeoutMs)
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{
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toRemove.Add(sessionKvp.Key);
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}
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}
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foreach (string key in toRemove)
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{
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//TODO: 清理会话的同时清理PlayerManager中的玩家数据
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if (_sessions.TryRemove(key, out var session))
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{
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Console.WriteLine($"[Transport] 清理超时会话：{session.EndPoint}");
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}
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}
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if (_isServer)
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{
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PrintSessionInfo();
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}
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}
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private async void SendPacketTo(Packet packet, IPEndPoint? endPoint)
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{
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try
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{
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var data = packet.ToBytes();
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await _client.SendAsync(data, data.Length, endPoint);
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}
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catch (Exception e)
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{
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Console.WriteLine($"[Transport] 发送错误：{e.Message}");
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}
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}
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private void PrintSessionInfo()
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{
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Console.WriteLine($"当前活跃会话数：{_sessions.Count}");
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foreach (var sessionKvp in _sessions)
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{
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var session = sessionKvp.Value;
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Console.WriteLine(
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$" 会话：{session.EndPoint}，发送SeqNum：{session.SendSequenceNumber}，期望接收：{session.ExpectedReceiveSequence}，待确认: {session.PendingAcks.Count}");
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}
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}
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}
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}
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