fix: kcp V1.23 - fixes #3296

Assets/Mirror/Transports/KCP/kcp2k/VERSION.txt

@@ -1,5 +1,11 @@
-V1.22 [2022-11-24]
+V1.23 [2022-12-07]
-- KcpPeer.RawInput: add offset parameter
+- KcpClient: rawReceiveBuffer exposed
+- fix: KcpServer RawSend uses connection.remoteEndPoint instead of the helper
+  'newClientEP'. fixes clients receiving the wrong messages meant for others.
+  https://github.com/MirrorNetworking/Mirror/issues/3296
+
+V1.22 [2022-11-30]
+- high level refactor, part two.
 
 V1.21 [2022-11-24]
 - high level refactor, part one.

Assets/Mirror/Transports/KCP/kcp2k/empty.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: d9ce2267cb8a4a1c9632025287e8da88
+timeCreated: 1669162433

Assets/Mirror/Transports/KCP/kcp2k/empty/KcpClientConnection.cs

@@ -0,0 +1 @@
+// removed 2022-11-23

Assets/Mirror/Transports/KCP/kcp2k/empty/KcpClientConnection.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: 96512e74aa8214a6faa8a412a7a07877
+timeCreated: 1602601237

Assets/Mirror/Transports/KCP/kcp2k/empty/KcpClientConnectionNonAlloc.cs

@@ -0,0 +1 @@
+// removed 2022-11-22

Assets/Mirror/Transports/KCP/kcp2k/empty/KcpClientConnectionNonAlloc.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: 4c1b235bbe054706bef6d092f361006e
+timeCreated: 1626430539

Assets/Mirror/Transports/KCP/kcp2k/empty/KcpClientNonAlloc.cs

@@ -0,0 +1 @@
+// removed 2022-11-22

Assets/Mirror/Transports/KCP/kcp2k/empty/KcpClientNonAlloc.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: 2cf0ccf7d551480bb5af08fcbe169f84
+timeCreated: 1626435264

Assets/Mirror/Transports/KCP/kcp2k/empty/KcpServerConnectionNonAlloc.cs

@@ -0,0 +1 @@
+// removed 2022-11-23

Assets/Mirror/Transports/KCP/kcp2k/empty/KcpServerConnectionNonAlloc.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: 4e1b74cc224b4c83a0f6c8d8da9090ab
+timeCreated: 1626430608

Assets/Mirror/Transports/KCP/kcp2k/highlevel/KcpServer.cs

@@ -4,6 +4,7 @@
 using System.Collections.Generic;
 using System.Net;
 using System.Net.Sockets;
+using UnityEngine;
 
 namespace kcp2k
 {
@@ -203,17 +204,27 @@ protected virtual bool RawReceive(byte[] buffer, out int size, out int connectio
         // io - out.
         // virtual so it may be modified for relays, nonalloc workaround, etc.
         // relays may need to prefix connId (and remoteEndPoint would be same for all)
-        protected virtual void RawSend(int connectionId, ArraySegment<byte> data, EndPoint remoteEndPoint)
+        protected virtual void RawSend(int connectionId, ArraySegment<byte> data)
         {
-            socket.SendTo(data.Array, data.Offset, data.Count, SocketFlags.None, remoteEndPoint);
+            // get the connection's endpoint
+            if (!connections.TryGetValue(connectionId, out KcpServerConnection connection))
+            {
+                Debug.LogWarning($"KcpServer.RawSend: invalid connectionId={connectionId}");
+                return;
+            }
+
+            // send to the the endpoint.
+            // do not send to 'newClientEP', as that's always reused.
+            // fixes https://github.com/MirrorNetworking/Mirror/issues/3296
+            socket.SendTo(data.Array, data.Offset, data.Count, SocketFlags.None, connection.remoteEndPoint);
         }
 
         protected virtual KcpServerConnection CreateConnection(int connectionId)
         {
-            // attach EndPoint EP to RawSend.
+            // attach connectionId to RawSend.
             // kcp needs a simple RawSend(byte[]) function.
             Action<ArraySegment<byte>> RawSendWrap =
-                data => RawSend(connectionId, data, newClientEP);
+                data => RawSend(connectionId, data);
 
             KcpPeer peer = new KcpPeer(RawSendWrap, NoDelay, Interval, FastResend, CongestionWindow, SendWindowSize, ReceiveWindowSize, Timeout, MaxRetransmits);
             return new KcpServerConnection(peer, newClientEP);

Assets/Mirror/Transports/KCP/kcp2k/highlevel/NonAlloc/KcpServerNonAlloc.cs

@@ -3,6 +3,7 @@
 using System;
 using System.Net;
 using System.Net.Sockets;
+using UnityEngine;
 using WhereAllocation;
 
 namespace kcp2k
@@ -58,10 +59,19 @@ protected override bool RawReceive(byte[] buffer, out int size, out int connecti
         }
 
         // make sure to pass IPEndPointNonAlloc as remoteEndPoint
-        protected override void RawSend(int connectionId, ArraySegment<byte> data, EndPoint remoteEndPoint)
+        protected override void RawSend(int connectionId, ArraySegment<byte> data)
         {
-            // where-allocation nonalloc send
+            // get the connection's endpoint
-            socket.SendTo_NonAlloc(data.Array, data.Offset, data.Count, SocketFlags.None, remoteEndPoint as IPEndPointNonAlloc);
+            if (!connections.TryGetValue(connectionId, out KcpServerConnection connection))
+            {
+                Debug.LogWarning($"KcpServerNonAlloc.RawSend: invalid connectionId={connectionId}");
+                return;
+            }
+
+            // where-allocation nonalloc send to the endpoint.
+            // do not send to 'newClientEP', as that's always reused.
+            // fixes https://github.com/MirrorNetworking/Mirror/issues/3296
+            socket.SendTo_NonAlloc(data.Array, data.Offset, data.Count, SocketFlags.None, connection.remoteEndPoint as IPEndPointNonAlloc);
         }
 
         protected override KcpServerConnection CreateConnection(int connectionId)
@@ -73,15 +83,15 @@ protected override KcpServerConnection CreateConnection(int connectionId)
 
             // for allocation free sending, we also need another
             // IPEndPointNonAlloc...
-            IPEndPointNonAlloc reusableSendEP = new IPEndPointNonAlloc(newClientEP.Address, newClientEP.Port);
+            IPEndPointNonAlloc endPointNonAlloc = new IPEndPointNonAlloc(newClientEP.Address, newClientEP.Port);
 
-            // attach reusable EP to RawSend.
+            // attach conectionId to RawSend.
             // kcp needs a simple RawSend(byte[]) function.
             Action<ArraySegment<byte>> RawSendWrap =
-                data => RawSend(connectionId, data, reusableSendEP);
+                data => RawSend(connectionId, data);
 
             KcpPeer peer = new KcpPeer(RawSendWrap, NoDelay, Interval, FastResend, CongestionWindow, SendWindowSize, ReceiveWindowSize, Timeout, MaxRetransmits);
-            return new KcpServerConnection(peer, newClientEP);
+            return new KcpServerConnection(peer, endPointNonAlloc);
         }
     }
 }