引入 KCP，进行基本迁移

Assets/Scripts/Network/NetworkTransport/ClientSession.cs

@@ -1,193 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Net;
-using System.Net.Sockets;
-
-namespace Network.NetworkTransport
-{
-    public class ClientSession
-    {
-        private ITransport _transport;
-
-        private IPEndPoint _remote;
-
-        public long LastActivityTs { get; private set; }
-
-        public uint SendSequenceNumber { get; private set; } = 0;
-
-        private int _currentTicks = 0;
-
-        private int _nextSendTicks = 0;
-
-        private int _sendInterval = 10;
-
-        // 重传时间 5s
-        private long _retransmitTicks = 5000;
-
-        // 上层交付
-        private readonly LinkedList<Packet> _sendQueue = new LinkedList<Packet>();
-
-        // 已发送但未确认
-        private readonly LinkedList<Packet> _sendBuffer = new LinkedList<Packet>();
-
-        // 已收到但乱序
-        private readonly LinkedList<Packet> _receiveBuffer = new LinkedList<Packet>();
-
-        // 已收到可交付
-        private readonly LinkedList<Packet> _receiveQueue = new LinkedList<Packet>();
-
-        private bool _hasReceived = false;
-
-        private uint _expectedAck = 0;
-
-        private readonly object _lockObj = new object();
-
-        public ClientSession(ITransport transport, IPEndPoint remote)
-        {
-            _transport = transport;
-            _remote = remote;
-            LastActivityTs = DateTimeOffset.UtcNow.ToUnixTimeMilliseconds();
-        }
-
-        public uint GetExpectedAck() => _expectedAck;
-        
-        public void SetSendInterval(int interval) => _sendInterval = interval;
-
-        private uint GetNextSendSequence()
-        {
-            lock (_lockObj)
-            {
-                return SendSequenceNumber++;
-            }
-        }
-
-        public void Tick(int currentTicks)
-        {
-            _currentTicks = currentTicks;
-            if (_currentTicks >= _nextSendTicks)
-            {
-                _nextSendTicks = currentTicks + _sendInterval;
-                SendPacketInternal();
-            }
-        }
-
-        public void SendPacket(byte[] data)
-        {
-            _sendQueue.AddLast(Packet.CreateDataPacket(GetNextSendSequence(), data));
-        }
-
-        public List<Packet> ReceivePackets()
-        {
-            var list = new List<Packet>();
-            lock (_lockObj)
-            {
-                while (_receiveQueue.Count > 0)
-                {
-                    var packet = _receiveQueue.First.Value;
-
-                    list.Add(packet);
-                    _receiveQueue.RemoveFirst();
-                }
-            }
-
-            return list;
-        }
-
-        private void SendPacketInternal()
-        {
-            if (_hasReceived)
-            {
-                var packet = Packet.CreateAckPacket(_expectedAck);
-                _sendBuffer.AddLast(packet);
-                var bytes = packet.ToBytes();
-                _transport.SendTo(bytes, _remote);
-                _hasReceived = false;
-            }
-
-            foreach (var packet in _receiveBuffer)
-            {
-                if (_currentTicks - packet.Timestamp > _retransmitTicks)
-                {
-                    var bytes = packet.ToBytes();
-                    _transport.SendTo(bytes, _remote);
-                }
-                else break;
-            }
-
-            while (_sendQueue.Count > 0)
-            {
-                var packet = _sendQueue.First.Value;
-                _sendBuffer.AddLast(packet);
-                var bytes = packet.ToBytes();
-                _transport.SendTo(bytes, _remote);
-            }
-        }
-
-        public void ReceivePacketsInternal(Packet packet)
-        {
-            uint seq = packet.SequenceNumber;
-
-            // 是否是按序到达的包
-            if (seq == _expectedAck)
-            {
-                _receiveQueue.AddLast(packet);
-                while (_receiveBuffer.Count > 0)
-                {
-                    var pendingPacket = _receiveBuffer.First.Value;
-                    if (seq != pendingPacket.SequenceNumber) break;
-                    seq++;
-                    _receiveQueue.AddLast(pendingPacket);
-                    _receiveBuffer.RemoveFirst();
-                }
-
-                _expectedAck = seq + 1;
-                _hasReceived = true;
-            }
-            // 将包按顺序追加在 receivingPackets 后面
-            else
-            {
-                var firstNode = _receiveBuffer.First;
-                while (firstNode.Next != null)
-                {
-                    if (firstNode.Value.SequenceNumber > seq)
-                    {
-                        var node = new LinkedListNode<Packet>(packet);
-                        _receiveBuffer.AddBefore(firstNode, node);
-                        break;
-                    }
-
-                    firstNode = firstNode.Next;
-                }
-
-                if (firstNode == null) _receiveBuffer.AddLast(packet);
-            }
-        }
-
-
-        public bool TryProcessReceiveSequence(uint sequenceNumber, out bool shouldDeliver)
-        {
-            lock (_lockObj)
-            {
-                LastActivityTs = DateTime.Now;
-
-                if (sequenceNumber == _expectedAck)
-                {
-                    _expectedAck++;
-                    _receivedSequences.Add(sequenceNumber);
-                    shouldDeliver = true;
-                    return true;
-                }
-                else if (sequenceNumber < _expectedAck)
-                {
-                    shouldDeliver = false;
-                    return _receivedSequences.Contains(sequenceNumber);
-                }
-                else
-                {
-                    shouldDeliver = false;
-                    return false;
-                }
-            }
-        }
-    }
-}

Assets/Scripts/Network/NetworkTransport/ClientSession.cs.meta

@@ -1,11 +0,0 @@
-fileFormatVersion: 2
-guid: ec6c25bc42967db499742dfa355380b7
-MonoImporter:
-  externalObjects: {}
-  serializedVersion: 2
-  defaultReferences: []
-  executionOrder: 0
-  icon: {instanceID: 0}
-  userData: 
-  assetBundleName: 
-  assetBundleVariant: 

Assets/Scripts/Network/NetworkTransport/ITransport.cs

@@ -6,6 +6,7 @@ namespace Network.NetworkTransport
 {
     public interface ITransport
     {
+        void Send(byte[] data);
         void SendTo(byte[] data, IPEndPoint target);
         void SendToAll(byte[] data);
         event Action<byte[], IPEndPoint> OnReceive;

Assets/Scripts/Network/NetworkTransport/Packet.cs

@@ -1,63 +0,0 @@
-using System;
-using System.Linq;
-using UnityEngine;
-
-namespace Network.NetworkTransport
-{
-    public enum PacketType : byte
-    {
-        Data = 1,
-        Ack = 2,
-    }
-
-    public struct Packet
-    {
-        public PacketType Type;
-        public uint SequenceNumber;
-        public byte[] Data;
-        public long Timestamp;
-
-        public byte[] ToBytes()
-        {
-            var result = new byte[1 + 4 + 8 + Data.Length];
-            result[0] = (byte)Type;
-            BitConverter.GetBytes(SequenceNumber).CopyTo(result, 1);
-            BitConverter.GetBytes(Timestamp).CopyTo(result, 5);
-            Data.CopyTo(result, 13);
-            return result;
-        }
-
-        public static Packet FromBytes(byte[] data)
-        {
-            return new Packet
-            {
-                Type = (PacketType)data[0],
-                SequenceNumber = BitConverter.ToUInt32(data, 1),
-                Timestamp = BitConverter.ToInt64(data, 5),
-                Data = new ArraySegment<byte>(data, 5, data.Length - 5).ToArray()
-            };
-        }
-
-        public static Packet CreateDataPacket(uint seqNum, byte[] data)
-        {
-            return new Packet
-            {
-                Type = PacketType.Data,
-                SequenceNumber = seqNum,
-                Data = data,
-                Timestamp = DateTimeOffset.UtcNow.ToUnixTimeMilliseconds()
-            };
-        }
-
-        public static Packet CreateAckPacket(uint seqNum)
-        {
-            return new Packet
-            {
-                Type = PacketType.Ack,
-                SequenceNumber = seqNum,
-                Data = Array.Empty<byte>(),
-                Timestamp = DateTimeOffset.UtcNow.ToUnixTimeMilliseconds()
-            };
-        }
-    }
-}

Assets/Scripts/Network/NetworkTransport/Packet.cs.meta

@@ -1,11 +0,0 @@
-fileFormatVersion: 2
-guid: b84a2cb7ffe3cd14180358559e526dbe
-MonoImporter:
-  externalObjects: {}
-  serializedVersion: 2
-  defaultReferences: []
-  executionOrder: 0
-  icon: {instanceID: 0}
-  userData: 
-  assetBundleName: 
-  assetBundleVariant: 

Assets/Scripts/Network/NetworkTransport/ReliableUdpTransport.cs

@@ -1,8 +1,7 @@
 using System;
-using System.Collections.Generic;
+using System.Collections.Concurrent;
 using System.Net;
 using System.Net.Sockets;
-using System.Threading;
 using System.Threading.Tasks;
 
 namespace Network.NetworkTransport
@@ -13,93 +12,103 @@ namespace Network.NetworkTransport
         private readonly IPEndPoint _defaultRemoteEndPoint;
         private readonly bool _isServer;
 
-        private readonly List<ClientSession> _sessions = new();
+        // Stage one keeps this class name for compatibility while collapsing it to plain UDP.
+        private readonly ConcurrentDictionary<string, IPEndPoint> _knownRemoteEndPoints = new();
 
-        private readonly Timer _retransmitTimer;
-        private readonly Timer _cleanupTimer;
-
-        //TODO: volatile 关键字
         private volatile bool _isRunning;
 
-        // 配置参数
-        private const int RetransmitTimeoutMs = 1000;
-        private const int SessionTimeoutMs = 30000;
-        private const int MaxRetransmitAttempts = 5;
-
         public event Action<byte[], IPEndPoint> OnReceive;
 
-        private Task _receiveTask;
+        private Task _receiveTask = Task.CompletedTask;
 
-        // 构造函数——服务端模式
         public ReliableUdpTransport(int listenPort)
         {
             _client = new UdpClient(listenPort);
             _isServer = true;
-            _retransmitTimer = new Timer(CheckRetransmit, null, 100, 100);
-            _cleanupTimer = new Timer(CleanupSessions, null, 5000, 5000);
             Console.WriteLine($"[Transport] 服务端模式，监听端口: {listenPort}");
         }
 
-        // 构造函数——客户端模式
         public ReliableUdpTransport(string serverIP, int serverPort)
         {
             _client = new UdpClient(0);
             _defaultRemoteEndPoint = new IPEndPoint(IPAddress.Parse(serverIP), serverPort);
-
             _isServer = false;
-            _retransmitTimer = new Timer(CheckRetransmit, null, 100, 100);
-            _cleanupTimer = new Timer(CleanupSessions, null, 5000, 5000);
             Console.WriteLine($"[Transport] 客户端模式，目标: {_defaultRemoteEndPoint}");
         }
 
         public async Task StartAsync()
         {
-            _sessions.Clear();
+            if (_isRunning)
+            {
+                return;
+            }
 
+            _knownRemoteEndPoints.Clear();
             _isRunning = true;
             Console.WriteLine("[Transport] 传输层启动");
-
-            // 开始接收数据
             _receiveTask = ReceiveLoop();
-            await Task.Delay(100); // 给接收循环一点启动时间
-        }
-
-        public void Tick()
-        {
-            foreach (var session in _sessions)
-            {
-                session.Tick(DateTime.UtcNow.Millisecond);
-            }
+            await Task.Yield();
         }
 
         public void Stop()
-        {
-            _isRunning = false;
-            _retransmitTimer.Dispose();
-            _cleanupTimer.Dispose();
-            _client.Close();
-            _sessions.Clear();
-            Console.WriteLine("[Transport] 传输层停止");
-        }
-
-        public async void SendTo(Packet packet, IPEndPoint target)
         {
             if (!_isRunning)
             {
                 return;
             }
 
-            var bytes = packet.ToBytes();
-            await _client.SendAsync(bytes, bytes.Length, target);
-            
-            Console.WriteLine($"[Transport] 发送数据包到 {target}");
+            _isRunning = false;
+            _client.Close();
+            _knownRemoteEndPoints.Clear();
+            Console.WriteLine("[Transport] 传输层停止");
+        }
+
+        public void Send(byte[] data)
+        {
+            if (_defaultRemoteEndPoint == null)
+            {
+                throw new InvalidOperationException("Default remote endpoint is not configured.");
+            }
+
+            SendTo(data, _defaultRemoteEndPoint);
+        }
+
+        public void SendTo(byte[] data, IPEndPoint target)
+        {
+            if (data == null)
+            {
+                throw new ArgumentNullException(nameof(data));
+            }
+
+            if (target == null)
+            {
+                throw new ArgumentNullException(nameof(target));
+            }
+
+            EnsureRunning();
+            RememberRemote(target);
+            _client.Send(data, data.Length, target);
+            Console.WriteLine($"[Transport] 发送数据到 {target}");
         }
 
         public void SendToAll(byte[] data)
         {
-            foreach (var session in _sessions)
+            if (data == null)
             {
-                session.SendPacket(data);
+                throw new ArgumentNullException(nameof(data));
+            }
+
+            EnsureRunning();
+
+            if (!_isServer)
+            {
+                throw new InvalidOperationException("SendToAll is only supported in server mode.");
+            }
+
+            foreach (var remoteEndPoint in _knownRemoteEndPoints.Values)
+            {
+                _client.Send(data, data.Length, remoteEndPoint);
+                Console.WriteLine($"[Transport] 广播数据到 {remoteEndPoint}");
             }
         }
 
@@ -110,20 +119,16 @@ namespace Network.NetworkTransport
                 try
                 {
                     var result = await _client.ReceiveAsync();
-                    var packet = Packet.FromBytes(result.Buffer);
-
-                    if (packet.Type == PacketType.Data)
-                    {
-                        HandleDataPacket(packet, result.RemoteEndPoint);
-                    }
-                    else if (packet.Type == PacketType.Ack)
-                    {
-                        HandleAckPacket(packet, result.RemoteEndPoint);
-                    }
+                    RememberRemote(result.RemoteEndPoint);
+                    OnReceive?.Invoke(result.Buffer, result.RemoteEndPoint);
                 }
-                catch (ObjectDisposedException)
+                catch (ObjectDisposedException) when (!_isRunning)
                 {
-                    return; // 正常关闭
+                    return;
+                }
+                catch (SocketException) when (!_isRunning)
+                {
+                    return;
                 }
                 catch (Exception e)
                 {
@@ -132,154 +137,22 @@ namespace Network.NetworkTransport
             }
         }
 
-        private void HandleDataPacket(Packet packet, IPEndPoint senderEndPoint)
-        {
-            var session = GetOrCreateSession(senderEndPoint);
-
-            Console.WriteLine(
-                $"[Transport] 收到数据包从{senderEndPoint} SeqNum={packet.SequenceNumber}, DataLen={packet.Data.Length}");
-
-            // 发送ACK
-            var ackPacket = Packet.CreateAckPacket(packet.SequenceNumber);
-            SendPacketTo(ackPacket, senderEndPoint);
-            Console.WriteLine($"[Transport] 发送ACK 到 {senderEndPoint} SeqNum={packet.SequenceNumber}");
-
-            // 检查是否应该交付
-            if (session.TryProcessReceiveSequence(packet.SequenceNumber, out bool shouldDeliver))
-            {
-                if (shouldDeliver)
-                {
-                    OnReceive?.Invoke(packet.Data, senderEndPoint);
-                    Console.WriteLine($"[Transport] 交付数据包从 {senderEndPoint} SeqNum={packet.SequenceNumber}");
-                }
-                else
-                {
-                    Console.WriteLine($"[Transport] 重复包从 {senderEndPoint} SeqNum={packet.SequenceNumber}，忽略");
-                }
-            }
-            else
-            {
-                // 乱序到达，暂存（简化处理：直接丢弃，依赖重传）
-                Console.WriteLine($"[Transport] 乱序包从 {senderEndPoint} SeqNum={packet.SequenceNumber}，丢弃");
-            }
-        }
-
-        private void HandleAckPacket(Packet packet, IPEndPoint senderEndPoint)
-        {
-            var session = GetOrCreateSession(senderEndPoint);
-            Console.WriteLine($"[Transport] 收到ACK从 {senderEndPoint} SeqNum={packet.SequenceNumber}");
-
-            if (session.PendingAcks.TryRemove(packet.SequenceNumber, out _))
-            {
-                Console.WriteLine($"[Transport] 确认包到 {senderEndPoint} SeqNum={packet.SequenceNumber}");
-            }
-        }
-
-        private ClientSession GetOrCreateSession(IPEndPoint endPoint)
-        {
-            string key = endPoint.ToString();
-            return _sessions.GetOrAdd(key, _ =>
-            {
-                var session = new ClientSession(endPoint);
-                Console.WriteLine($"创建新会话：{endPoint}");
-                return session;
-            });
-        }
-
-        private void CheckRetransmit(object state)
+        private void EnsureRunning()
         {
             if (!_isRunning)
+            {
+                throw new InvalidOperationException("Transport has not been started.");
+            }
+        }
+
+        private void RememberRemote(IPEndPoint remoteEndPoint)
+        {
+            if (remoteEndPoint == null)
             {
                 return;
             }
 
-            var now = DateTime.Now;
-            var toRetransmit = new List<(IPEndPoint target, uint seqNum, Packet packet)>();
-
-            foreach (var sessionKvp in _sessions)
-            {
-                var session = sessionKvp.Value;
-                foreach (var ackKvp in session.PendingAcks)
-                {
-                    var timeSinceLastSend = now - ackKvp.Value.sendTime;
-                    if (timeSinceLastSend.TotalMilliseconds > RetransmitTimeoutMs)
-                    {
-                        toRetransmit.Add((session.EndPoint, ackKvp.Key, ackKvp.Value.packet));
-                    }
-                }
-            }
-
-
-            foreach (var (target, seqNum, packet) in toRetransmit)
-            {
-                var session = GetOrCreateSession(target);
-                if (session.PendingAcks.ContainsKey(seqNum))
-                {
-                    // 更新发送时间
-                    session.PendingAcks[seqNum] = (packet, now);
-                    SendPacketTo(packet, target);
-                    Console.WriteLine($"[Transport] 重传包到 {target} SeqNum={seqNum}");
-                }
-            }
-        }
-
-        private void CleanupSessions(object state)
-        {
-            if (!_isRunning)
-            {
-                return;
-            }
-
-            var now = DateTime.Now;
-            var toRemove = new List<string>();
-
-            foreach (var sessionKvp in _sessions)
-            {
-                var session = sessionKvp.Value;
-                var timeSinceLastActivity = now - session.LastActivity;
-
-                if (timeSinceLastActivity.TotalMilliseconds > SessionTimeoutMs)
-                {
-                    toRemove.Add(sessionKvp.Key);
-                }
-            }
-
-            foreach (string key in toRemove)
-            {
-                if (_sessions.TryRemove(key, out var session))
-                {
-                    Console.WriteLine($"[Transport] 清理超时会话：{session.EndPoint}");
-                }
-            }
-
-            if (_isServer)
-            {
-                PrintSessionInfo();
-            }
-        }
-
-        private async void SendPacketTo(Packet packet, IPEndPoint endPoint)
-        {
-            try
-            {
-                var data = packet.ToBytes();
-                await _client.SendAsync(data, data.Length, endPoint);
-            }
-            catch (Exception e)
-            {
-                Console.WriteLine($"[Transport] 发送错误：{e.Message}");
-            }
-        }
-
-        private void PrintSessionInfo()
-        {
-            Console.WriteLine($"当前活跃会话数：{_sessions.Count}");
-            foreach (var sessionKvp in _sessions)
-            {
-                var session = sessionKvp.Value;
-                Console.WriteLine(
-                    $"  会话：{session.EndPoint}，发送SeqNum：{session.SendSequenceNumber}，期望接收：{session.GetExpectedAck()}，待确认: {session.PendingAcks.Count}");
-            }
+            _knownRemoteEndPoints[remoteEndPoint.ToString()] = remoteEndPoint;
         }
     }
-}
+}