Merge pull request #2 from merval/fix/posix-net-layer

Fix POSIX LAN disconnect handling
2026-05-26 05:35:50 +00:00 · 2026-05-12 18:12:32 -04:00
parent aad5c68b7e 62d9b1f742
commit bf6ca168c4
15 changed files with 756 additions and 48 deletions
--- a/Linux/LinuxCompat.h
+++ b/Linux/LinuxCompat.h
@@ -192,9 +192,18 @@ typedef union _LARGE_INTEGER {
 #define VK_UP        0x26
 #define VK_RIGHT     0x27
 #define VK_DOWN      0x28
+#define VK_F1        0x70
+#define VK_F2        0x71
 #define VK_F3        0x72
 #define VK_F4        0x73
 #define VK_F5        0x74
+#define VK_F6        0x75
+#define VK_F7        0x76
+#define VK_F8        0x77
+#define VK_F9        0x78
+#define VK_F10       0x79
+#define VK_F11       0x7A
+#define VK_F12       0x7B
 #define VK_LSHIFT    0xA0
 #define VK_LCONTROL  0xA2
 #ifndef WHEEL_DELTA
--- a/Linux/PosixNetLayer.cpp
+++ b/Linux/PosixNetLayer.cpp
@@ -683,6 +683,8 @@ void WinsockNetLayer::HandleDataReceived(uint8_t fromSmallId, uint8_t toSmallId,
            pthread_mutex_lock(&s_earlyDataLock);
            s_earlyDataBuffers[fromSmallId].insert(
                s_earlyDataBuffers[fromSmallId].end(), data, data + dataSize);
+            app.DebugPrintf("POSIX LAN: Buffered %u early bytes for smallId=%d (total=%d)\n",
+                dataSize, fromSmallId, (int)s_earlyDataBuffers[fromSmallId].size());
            pthread_mutex_unlock(&s_earlyDataLock);
        }
        return;
@@ -698,6 +700,8 @@ void WinsockNetLayer::HandleDataReceived(uint8_t fromSmallId, uint8_t toSmallId,
            pthread_mutex_lock(&s_earlyDataLock);
            s_earlyDataBuffers[fromSmallId].insert(
                s_earlyDataBuffers[fromSmallId].end(), data, data + dataSize);
+            app.DebugPrintf("POSIX LAN: Buffered %u bytes waiting for socket smallId=%d (total=%d)\n",
+                dataSize, fromSmallId, (int)s_earlyDataBuffers[fromSmallId].size());
            pthread_mutex_unlock(&s_earlyDataLock);
        }
    }
@@ -722,6 +726,8 @@ void WinsockNetLayer::FlushPendingData()
        ::Socket *pSocket = pPlayer->GetSocket();
        if (pSocket == NULL) continue;

+        app.DebugPrintf("POSIX LAN: Flushing %d early bytes for smallId=%d\n",
+            (int)s_earlyDataBuffers[i].size(), (int)i);
        pSocket->pushDataToQueue(s_earlyDataBuffers[i].data(),
            (DWORD)s_earlyDataBuffers[i].size(), false);
        s_earlyDataBuffers[i].clear();
@@ -796,15 +802,6 @@ void* WinsockNetLayer::AcceptThreadProc(void* /*param*/)
            continue;
        }

-        uint8_t assignBuf[1] = { assignedSmallId };
-        ssize_t sent = send(clientSocket, (const char *)assignBuf, 1, MSG_NOSIGNAL);
-        if (sent != 1)
-        {
-            app.DebugPrintf("Failed to send small ID to client\n");
-            close(clientSocket);
-            continue;
-        }
-
        int flags = fcntl(clientSocket, F_GETFL, 0);
        fcntl(clientSocket, F_SETFL, flags | O_NONBLOCK);

@@ -842,7 +839,17 @@ void* WinsockNetLayer::AcceptThreadProc(void* /*param*/)

        pthread_mutex_lock(&s_pendingJoinLock);
        s_pendingJoinSmallIds.push_back(assignedSmallId);
+        app.DebugPrintf("POSIX LAN: Queued pending join for smallId=%d\n", assignedSmallId);
        pthread_mutex_unlock(&s_pendingJoinLock);
+
+        uint8_t assignBuf[1] = { assignedSmallId };
+        ssize_t sent = send(clientSocket, (const char *)assignBuf, 1, MSG_NOSIGNAL);
+        if (sent != 1)
+        {
+            app.DebugPrintf("POSIX LAN: Failed to send small ID to client smallId=%d\n", assignedSmallId);
+            MarkConnectionDisconnected(assignedSmallId);
+            continue;
+        }
    }
    return NULL;
 }
@@ -863,7 +870,11 @@ bool WinsockNetLayer::ProcessRecvData(Win64RemoteConnection &conn)
                ((uint32_t)conn.recvBuffer[3]);

            if (packetSize <= 0 || (unsigned int)packetSize > WIN64_NET_MAX_PACKET_SIZE)
+            {
+                app.DebugPrintf("POSIX LAN: Invalid packet size %d from smallId=%d\n",
+                    packetSize, conn.smallId);
                return false;
+            }

            conn.currentPacketSize = packetSize;
            conn.readingHeader = false;
@@ -889,6 +900,50 @@ bool WinsockNetLayer::ProcessRecvData(Win64RemoteConnection &conn)
    return true;
 }

+void WinsockNetLayer::MarkConnectionDisconnected(uint8_t smallId)
+{
+    bool shouldNotify = false;
+
+    pthread_mutex_lock(&s_connectionsLock);
+    if ((size_t)smallId < s_connections.size())
+    {
+        Win64RemoteConnection &conn = s_connections[smallId];
+        shouldNotify = conn.active;
+        conn.active = false;
+
+        if (conn.tcpSocket != INVALID_SOCKET)
+        {
+            if (s_epollFd >= 0)
+                epoll_ctl(s_epollFd, EPOLL_CTL_DEL, conn.tcpSocket, NULL);
+            shutdown(conn.tcpSocket, SHUT_RDWR);
+            close(conn.tcpSocket);
+            conn.tcpSocket = INVALID_SOCKET;
+        }
+
+        pthread_mutex_lock(&conn.sendBufLock);
+        conn.sendBufferUsed = 0;
+        pthread_mutex_unlock(&conn.sendBufLock);
+
+        conn.recvBufferUsed = 0;
+        conn.currentPacketSize = -1;
+        conn.readingHeader = true;
+    }
+    pthread_mutex_unlock(&s_connectionsLock);
+
+    pthread_mutex_lock(&s_earlyDataLock);
+    if ((size_t)smallId < s_earlyDataBuffers.size())
+        s_earlyDataBuffers[smallId].clear();
+    pthread_mutex_unlock(&s_earlyDataLock);
+
+    if (shouldNotify)
+    {
+        pthread_mutex_lock(&s_disconnectLock);
+        s_disconnectedSmallIds.push_back(smallId);
+        pthread_mutex_unlock(&s_disconnectLock);
+        app.DebugPrintf("POSIX LAN: Queued disconnect for smallId=%d\n", smallId);
+    }
+}
+
 void* WinsockNetLayer::EpollThreadProc(void* /*param*/)
 {
    struct epoll_event events[WIN64_NET_EPOLL_MAX_EVENTS];
@@ -915,14 +970,7 @@ void* WinsockNetLayer::EpollThreadProc(void* /*param*/)

            if (events[i].events & (EPOLLERR | EPOLLHUP))
            {
-                conn.active = false;
-                epoll_ctl(s_epollFd, EPOLL_CTL_DEL, conn.tcpSocket, NULL);
-                close(conn.tcpSocket);
-                conn.tcpSocket = INVALID_SOCKET;
-
-                pthread_mutex_lock(&s_disconnectLock);
-                s_disconnectedSmallIds.push_back(smallId);
-                pthread_mutex_unlock(&s_disconnectLock);
+                MarkConnectionDisconnected(smallId);
                continue;
            }

@@ -940,6 +988,7 @@ void* WinsockNetLayer::EpollThreadProc(void* /*param*/)
                        uint8_t *newBuf = (uint8_t *)realloc(conn.recvBuffer, newSize);
                        if (!newBuf)
                        {
+                            app.DebugPrintf("POSIX LAN: Failed to grow receive buffer for smallId=%d\n", smallId);
                            disconnected = true;
                            break;
                        }
@@ -974,14 +1023,7 @@ void* WinsockNetLayer::EpollThreadProc(void* /*param*/)

                if (disconnected)
                {
-                    conn.active = false;
-                    epoll_ctl(s_epollFd, EPOLL_CTL_DEL, conn.tcpSocket, NULL);
-                    close(conn.tcpSocket);
-                    conn.tcpSocket = INVALID_SOCKET;
-
-                    pthread_mutex_lock(&s_disconnectLock);
-                    s_disconnectedSmallIds.push_back(smallId);
-                    pthread_mutex_unlock(&s_disconnectLock);
+                    MarkConnectionDisconnected(smallId);
                }
            }
        }
@@ -998,6 +1040,7 @@ void WinsockNetLayer::FlushSendBuffers()
        if (!conn.active || conn.tcpSocket == INVALID_SOCKET)
            continue;

+        bool disconnectAfterSendError = false;
        pthread_mutex_lock(&conn.sendBufLock);
            if (conn.sendBufferUsed > 0)
        {
@@ -1007,7 +1050,11 @@ void WinsockNetLayer::FlushSendBuffers()
                ssize_t sent = send(conn.tcpSocket, (const char *)conn.sendBuffer + totalSent,
                    conn.sendBufferUsed - totalSent, MSG_NOSIGNAL);
                if (sent <= 0)
+                {
+                    app.DebugPrintf("POSIX LAN: Send failed for smallId=%d errno=%d\n", (int)i, errno);
+                    disconnectAfterSendError = true;
                    break;
+                }
                totalSent += (int)sent;
            }
            if (totalSent < conn.sendBufferUsed && totalSent > 0)
@@ -1021,6 +1068,9 @@ void WinsockNetLayer::FlushSendBuffers()
            }
        }
        pthread_mutex_unlock(&conn.sendBufLock);
+
+        if (disconnectAfterSendError)
+            MarkConnectionDisconnected((uint8_t)i);
    }
    pthread_mutex_unlock(&s_connectionsLock);
 }
@@ -1036,6 +1086,8 @@ bool WinsockNetLayer::PopDisconnectedSmallId(uint8_t *outSmallId)
        found = true;
    }
    pthread_mutex_unlock(&s_disconnectLock);
+    if (found)
+        app.DebugPrintf("POSIX LAN: Popped disconnect for smallId=%d\n", *outSmallId);
    return found;
 }

@@ -1044,6 +1096,7 @@ void WinsockNetLayer::PushFreeSmallId(uint8_t smallId)
    pthread_mutex_lock(&s_freeSmallIdLock);
    s_freeSmallIds.push_back(smallId);
    pthread_mutex_unlock(&s_freeSmallIdLock);
+    app.DebugPrintf("POSIX LAN: Returned smallId=%d to free list\n", smallId);
 }

 bool WinsockNetLayer::PopPendingJoinSmallId(uint8_t *outSmallId)
@@ -1057,6 +1110,8 @@ bool WinsockNetLayer::PopPendingJoinSmallId(uint8_t *outSmallId)
        found = true;
    }
    pthread_mutex_unlock(&s_pendingJoinLock);
+    if (found)
+        app.DebugPrintf("POSIX LAN: Popped pending join for smallId=%d\n", *outSmallId);
    return found;
 }

@@ -1068,21 +1123,8 @@ bool WinsockNetLayer::IsSmallIdConnected(uint8_t smallId)

 void WinsockNetLayer::CloseConnectionBySmallId(uint8_t smallId)
 {
-    pthread_mutex_lock(&s_connectionsLock);
-    if ((size_t)smallId < s_connections.size() && s_connections[smallId].active && s_connections[smallId].tcpSocket != INVALID_SOCKET)
-    {
-        epoll_ctl(s_epollFd, EPOLL_CTL_DEL, s_connections[smallId].tcpSocket, NULL);
-        shutdown(s_connections[smallId].tcpSocket, SHUT_RDWR);
-        close(s_connections[smallId].tcpSocket);
-        s_connections[smallId].tcpSocket = INVALID_SOCKET;
-        app.DebugPrintf("POSIX LAN: Force-closed TCP connection for smallId=%d\n", smallId);
-    }
-    pthread_mutex_unlock(&s_connectionsLock);
-
-    pthread_mutex_lock(&s_earlyDataLock);
-    if ((size_t)smallId < s_earlyDataBuffers.size())
-        s_earlyDataBuffers[smallId].clear();
-    pthread_mutex_unlock(&s_earlyDataLock);
+    MarkConnectionDisconnected(smallId);
+    app.DebugPrintf("POSIX LAN: Force-closed TCP connection for smallId=%d\n", smallId);
 }

 void* WinsockNetLayer::ClientRecvThreadProc(void* /*param*/)
--- a/Linux/PosixNetLayer.h
+++ b/Linux/PosixNetLayer.h
@@ -154,6 +154,7 @@ private:
    static void* DiscoveryThreadProc(void* param);
    static void* AsyncJoinThreadProc(void* param);
    static bool ProcessRecvData(Win64RemoteConnection &conn);
+    static void MarkConnectionDisconnected(uint8_t smallId);

    static SOCKET s_listenSocket;
    static SOCKET s_hostConnectionSocket;
--- a/Minecraft.Server.vcxproj
+++ b/Minecraft.Server.vcxproj
@@ -30,20 +30,20 @@
  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'" Label="Configuration">
    <ConfigurationType>Application</ConfigurationType>
    <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v110</PlatformToolset>
+    <PlatformToolset>v145</PlatformToolset>
  </PropertyGroup>
  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'" Label="Configuration">
    <ConfigurationType>Application</ConfigurationType>
    <CharacterSet>MultiByte</CharacterSet>
-    <PlatformToolset>v110</PlatformToolset>
+    <PlatformToolset>v145</PlatformToolset>
  </PropertyGroup>
  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug-Linux|x64'" Label="Configuration">
    <ConfigurationType>Makefile</ConfigurationType>
-    <PlatformToolset>v143</PlatformToolset>
+    <PlatformToolset>v145</PlatformToolset>
  </PropertyGroup>
  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release-Linux|x64'" Label="Configuration">
    <ConfigurationType>Makefile</ConfigurationType>
-    <PlatformToolset>v143</PlatformToolset>
+    <PlatformToolset>v145</PlatformToolset>
  </PropertyGroup>
  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
  <ImportGroup Label="ExtensionSettings">
@@ -72,7 +72,8 @@
    <OutDir>$(SolutionDir)x64_Server_Release\</OutDir>
    <IntDir>x64_Server_Release\</IntDir>
    <IncludePath>$(ProjectDir)\..\Minecraft.World\x64headers;$(ProjectDir)\..\Minecraft.Client\Xbox\Sentient\Include;$(IncludePath)</IncludePath>
-  </PropertyGroup>  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug-Linux|x64'">
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug-Linux|x64'">
    <OutDir>$(SolutionDir)Linux_Server_Debug\</OutDir>
    <IntDir>Linux_Server_Debug\</IntDir>
    <NMakeBuildCommandLine>"$(ProjectDir)Linux\build.bat" Debug</NMakeBuildCommandLine>
@@ -93,7 +94,8 @@
    <NMakePreprocessorDefinitions>__linux__;_DEDICATED_SERVER;_CONTENT_PACKAGE;_LARGE_WORLDS;_WINDOWS64;WITH_SERVER_CODE;_CRT_NON_CONFORMING_SWPRINTFS;_CRT_SECURE_NO_WARNINGS</NMakePreprocessorDefinitions>
    <NMakeIncludeSearchPath>$(ProjectDir)Linux;$(ProjectDir)Linux\stubs;$(ProjectDir);$(ProjectDir)\..\Minecraft.Client;$(ProjectDir)\..\Minecraft.World;$(ProjectDir)\..\Minecraft.World\x64headers;$(ProjectDir)\..\Minecraft.Client\Windows64\Iggy\include;$(ProjectDir)\..\Minecraft.Client\Xbox\Sentient\Include</NMakeIncludeSearchPath>
    <AdditionalOptions>-std=c++11</AdditionalOptions>
-  </PropertyGroup>  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">
+  </PropertyGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">
    <ClCompile>
      <PrecompiledHeader>Use</PrecompiledHeader>
      <PrecompiledHeaderFile>stdafx.h</PrecompiledHeaderFile>
@@ -703,4 +705,4 @@
  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
  <ImportGroup Label="ExtensionTargets">
  </ImportGroup>
-</Project>
+</Project>
--- a/Minecraft.Server.vcxproj.filters
+++ b/Minecraft.Server.vcxproj.filters
@@ -832,5 +832,104 @@
    <ClCompile Include="Linux\PosixNetLayer.cpp">
      <Filter>Source Files\Linux</Filter>
    </ClCompile>
+    <ClCompile Include="..\Minecraft.Client\Platform_Libs\Dev\Storage\4J_Storage.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="..\Minecraft.Client\Platform_Libs\Dev\Storage\STO_DLC.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="..\Minecraft.Client\Platform_Libs\Dev\Storage\STO_Main.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="..\Minecraft.Client\Platform_Libs\Dev\Storage\STO_SaveGame.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="..\Minecraft.Client\Platform_Libs\Dev\Profile\4J_Profile.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="..\Minecraft.Client\Platform_Libs\Dev\Profile\PRO_AwardManager.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="..\Minecraft.Client\Platform_Libs\Dev\Profile\PRO_Data.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="..\Minecraft.Client\Platform_Libs\Dev\Profile\PRO_Main.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="..\Minecraft.Client\Platform_Libs\Dev\Profile\PRO_RichPresence.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="..\Minecraft.Client\Platform_Libs\Dev\Profile\PRO_Sys.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="..\Minecraft.Client\Platform_Libs\Dev\Render\4J_Render.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="..\Minecraft.Client\Platform_Libs\Dev\Render\RendererCBuff.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="..\Minecraft.Client\Platform_Libs\Dev\Render\RendererCore.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="..\Minecraft.Client\Platform_Libs\Dev\Render\RendererMatrix.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="..\Minecraft.Client\Platform_Libs\Dev\Render\RendererState.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="..\Minecraft.Client\Platform_Libs\Dev\Render\RendererTexture.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="..\Minecraft.Client\Platform_Libs\Dev\Render\RendererVertex.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="..\Minecraft.Client\Platform_Libs\Dev\Render\microprofile\microprofile.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="..\Minecraft.Client\Platform_Libs\Dev\Render\libpng\png.c">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="..\Minecraft.Client\Platform_Libs\Dev\Render\libpng\pngerror.c">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="..\Minecraft.Client\Platform_Libs\Dev\Render\libpng\pngget.c">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="..\Minecraft.Client\Platform_Libs\Dev\Render\libpng\pngmem.c">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="..\Minecraft.Client\Platform_Libs\Dev\Render\libpng\pngpread.c">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="..\Minecraft.Client\Platform_Libs\Dev\Render\libpng\pngread.c">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="..\Minecraft.Client\Platform_Libs\Dev\Render\libpng\pngrio.c">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="..\Minecraft.Client\Platform_Libs\Dev\Render\libpng\pngrtran.c">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="..\Minecraft.Client\Platform_Libs\Dev\Render\libpng\pngrutil.c">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="..\Minecraft.Client\Platform_Libs\Dev\Render\libpng\pngset.c">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="..\Minecraft.Client\Platform_Libs\Dev\Render\libpng\pngtrans.c">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="..\Minecraft.Client\Platform_Libs\Dev\Render\libpng\pngwio.c">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="..\Minecraft.Client\Platform_Libs\Dev\Render\libpng\pngwrite.c">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="..\Minecraft.Client\Platform_Libs\Dev\Render\libpng\pngwtran.c">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="..\Minecraft.Client\Platform_Libs\Dev\Render\libpng\pngwutil.c">
+      <Filter>Source Files</Filter>
+    </ClCompile>
  </ItemGroup>
-</Project>
+</Project>
--- a/docker/Dockerfile
+++ b/docker/Dockerfile
@@ -0,0 +1,51 @@
+# syntax=docker/dockerfile:1
+
+FROM debian:bookworm-slim AS build
+
+RUN apt-get update \
+    && apt-get install -y --no-install-recommends \
+        build-essential \
+        ca-certificates \
+        cmake \
+    && rm -rf /var/lib/apt/lists/*
+
+WORKDIR /src
+ARG BUILD_JOBS=2
+
+# Build with the LCEMP repository root as context:
+# docker build -f Minecraft.Server/docker/Dockerfile .
+COPY cmake ./cmake
+COPY Minecraft.Client ./Minecraft.Client
+COPY Minecraft.World ./Minecraft.World
+COPY Minecraft.Server ./Minecraft.Server
+
+RUN cmake -S Minecraft.Server -B /build -DCMAKE_BUILD_TYPE=Release \
+    && cmake --build /build --target MinecraftDedicatedServer --parallel "${BUILD_JOBS}" \
+    && strip /build/MinecraftDedicatedServer
+
+FROM debian:bookworm-slim AS runtime
+
+RUN apt-get update \
+    && apt-get install -y --no-install-recommends \
+        ca-certificates \
+        libstdc++6 \
+    && rm -rf /var/lib/apt/lists/* \
+    && useradd --create-home --home-dir /home/lcemp --shell /usr/sbin/nologin lcemp \
+    && mkdir -p /data \
+    && chown -R lcemp:lcemp /data
+
+COPY --from=build /build/MinecraftDedicatedServer /usr/local/bin/MinecraftDedicatedServer
+COPY Minecraft.Server/docker/entrypoint.sh /usr/local/bin/lcemp-entrypoint
+
+RUN chmod +x /usr/local/bin/lcemp-entrypoint
+
+WORKDIR /data
+VOLUME ["/data"]
+
+EXPOSE 25565/tcp
+EXPOSE 25565/udp
+EXPOSE 25566/udp
+
+USER lcemp
+ENTRYPOINT ["lcemp-entrypoint"]
+CMD ["MinecraftDedicatedServer"]
--- a/docker/Dockerfile.dockerignore
+++ b/docker/Dockerfile.dockerignore
@@ -0,0 +1,33 @@
+.git
+.github
+.vs
+build
+build_linux
+build_dedicated
+ipch
+x64
+x64_Server_Debug
+x64_Server_Release
+
+**/.git
+**/.vs
+**/build
+**/build_linux
+**/build_dedicated
+**/ipch
+**/x64
+**/x64_Server_Debug
+**/x64_Server_Release
+**/*.idb
+**/*.ilk
+**/*.lastbuildstate
+**/*.log
+**/*.obj
+**/*.opensdf
+**/*.pch
+**/*.pdb
+**/*.sdf
+**/*.sln
+**/*.suo
+**/*.tlog
+**/*.user
--- a/docker/Dockerfile.prebuilt
+++ b/docker/Dockerfile.prebuilt
@@ -0,0 +1,28 @@
+# syntax=docker/dockerfile:1
+
+FROM debian:bookworm-slim AS runtime
+
+RUN apt-get update \
+    && apt-get install -y --no-install-recommends \
+        ca-certificates \
+        libstdc++6 \
+    && rm -rf /var/lib/apt/lists/* \
+    && useradd --create-home --home-dir /home/lcemp --shell /usr/sbin/nologin lcemp \
+    && mkdir -p /data \
+    && chown -R lcemp:lcemp /data
+
+COPY build/MinecraftDedicatedServer /usr/local/bin/MinecraftDedicatedServer
+COPY Minecraft.Server/docker/entrypoint.sh /usr/local/bin/lcemp-entrypoint
+
+RUN chmod +x /usr/local/bin/MinecraftDedicatedServer /usr/local/bin/lcemp-entrypoint
+
+WORKDIR /data
+VOLUME ["/data"]
+
+EXPOSE 25565/tcp
+EXPOSE 25565/udp
+EXPOSE 25566/udp
+
+USER lcemp
+ENTRYPOINT ["lcemp-entrypoint"]
+CMD ["MinecraftDedicatedServer"]
--- a/docker/Dockerfile.prebuilt.dockerignore
+++ b/docker/Dockerfile.prebuilt.dockerignore
@@ -0,0 +1,23 @@
+.git
+.github
+.vs
+build/*
+!build/MinecraftDedicatedServer
+Minecraft.Client
+Minecraft.World
+
+**/.git
+**/.vs
+**/*.idb
+**/*.ilk
+**/*.lastbuildstate
+**/*.log
+**/*.obj
+**/*.opensdf
+**/*.pch
+**/*.pdb
+**/*.sdf
+**/*.sln
+**/*.suo
+**/*.tlog
+**/*.user
--- a/docker/README.md
+++ b/docker/README.md
@@ -0,0 +1,125 @@
+# Docker
+
+This directory builds and runs the Linux dedicated server in a container.
+
+Build from the LCEMP repository root, not from `Minecraft.Server`, because the server CMake project depends on sibling `Minecraft.Client`, `Minecraft.World`, and `cmake` directories.
+
+On Windows, use the build wrapper from `Minecraft.Server/docker`. It uses this order:
+
+1. Copy an existing Linux binary from `build/MinecraftDedicatedServer`.
+2. Download a GitHub release asset when `GITHUB_REPOSITORY` is configured.
+3. Fall back to the full Docker build.
+
+```powershell
+.\build-image.ps1
+```
+
+On Linux/macOS:
+
+```bash
+./build-image.sh
+```
+
+You can also call Docker directly for a full build:
+
+```bash
+docker build -f Minecraft.Server/docker/Dockerfile -t lcemp-server .
+```
+
+The Dockerfile defaults to `BUILD_JOBS=2` to avoid overloading Docker Desktop/WSL during the large C++ compile. Override it on stronger Linux hosts:
+
+```bash
+docker build -f Minecraft.Server/docker/Dockerfile -t lcemp-server --build-arg BUILD_JOBS=8 .
+```
+
+To force the wrapper to do a full build:
+
+```powershell
+.\build-image.ps1 -ForceFullBuild
+```
+
+To download a prebuilt binary from a public GitHub release before falling back to the full build:
+
+```powershell
+.\build-image.ps1 `
+  -GitHubRepo "owner/repo" `
+  -GitHubReleaseTag "latest" `
+  -GitHubAssetName "MinecraftDedicatedServer"
+```
+
+The shell wrapper uses equivalent environment variables:
+
+```bash
+GITHUB_REPOSITORY=owner/repo \
+GITHUB_RELEASE_TAG=latest \
+GITHUB_ASSET_NAME=MinecraftDedicatedServer \
+./build-image.sh
+```
+
+To build a runtime image from an already-built Linux binary directly:
+
+```bash
+docker build -f Minecraft.Server/docker/Dockerfile.prebuilt -t lcemp-server .
+```
+
+Run with a persistent data directory:
+
+```bash
+docker run --rm -it \
+  -p 25565:25565/tcp \
+  -p 25565:25565/udp \
+  -p 25566:25566/udp \
+  -v lcemp-data:/data \
+  -e MOTD="A Minecraft LCE Server" \
+  -e LEVEL_NAME="world" \
+  lcemp-server
+```
+
+Or use Compose from this directory:
+
+```bash
+docker compose up --build
+```
+
+To use Compose with an existing `build/MinecraftDedicatedServer` binary:
+
+```bash
+docker compose -f compose.yaml -f compose.prebuilt.yaml up --build
+```
+
+The entrypoint writes `/data/server.properties` from environment variables on every start, then launches `MinecraftDedicatedServer` from `/data` so generated worlds, lists, and server data persist in the mounted volume.
+
+## Environment Variables
+
+| Environment variable | server.properties key | Default |
+|---|---|---|
+| `SERVER_PORT` | `server-port` | `25565` |
+| `SERVER_IP` | `server-ip` | empty |
+| `LEVEL_NAME` | `level-name` | `world` |
+| `LEVEL_SEED` | `level-seed` | empty |
+| `LEVEL_SIZE` | `level-size` | `large` |
+| `GAMEMODE` | `gamemode` | `0` |
+| `DIFFICULTY` | `difficulty` | `2` |
+| `MAX_PLAYERS` | `max-players` | `8` |
+| `PVP` | `pvp` | `true` |
+| `TRUST_PLAYERS` | `trust-players` | `true` |
+| `FIRE_SPREADS` | `fire-spreads` | `true` |
+| `TNT_EXPLODES` | `tnt-explodes` | `true` |
+| `STRUCTURES` | `structures` | `true` |
+| `SPAWN_ANIMALS` | `spawn-animals` | `true` |
+| `SPAWN_NPCS` | `spawn-npcs` | `true` |
+| `ONLINE_MODE` | `online-mode` | `false` |
+| `SHOW_GAMERTAGS` | `show-gamertags` | `true` |
+| `MOTD` | `motd` | `A Minecraft LCE Server` |
+| `WHITE_LIST` | `white-list` | `false` |
+| `VOICE_CHAT` | `voice-chat` | `false` |
+| `ENABLE_CHAT` | `enable-chat` | `false` |
+| `ADVERTISE_LAN` | `advertise-lan` | `true` |
+
+`SERVER_PROPERTIES_FILE` can override the generated properties path. The default is `/data/server.properties`.
+
+LAN discovery uses UDP broadcast. If clients cannot discover the server through Docker port publishing, run the container with host networking on Linux:
+
+```bash
+docker run --rm -it --network host -v lcemp-data:/data lcemp-server
+```
--- a/docker/build-image.ps1
+++ b/docker/build-image.ps1
@@ -0,0 +1,97 @@
+param(
+    [string]$Image = "lcemp-server:local",
+    [int]$BuildJobs = 2,
+    [string]$GitHubRepo = $env:GITHUB_REPOSITORY,
+    [string]$GitHubReleaseTag = $env:GITHUB_RELEASE_TAG,
+    [string]$GitHubAssetName = $(if ($env:GITHUB_ASSET_NAME) { $env:GITHUB_ASSET_NAME } else { "MinecraftDedicatedServer" }),
+    [switch]$ForceFullBuild
+)
+
+$ErrorActionPreference = "Stop"
+
+$ScriptDir = Split-Path -Parent $MyInvocation.MyCommand.Path
+$RepoRoot = Resolve-Path (Join-Path $ScriptDir "../..")
+$PrebuiltBinary = Join-Path $RepoRoot "build/MinecraftDedicatedServer"
+
+function Invoke-DockerPrebuiltBuild {
+    Write-Host "Using prebuilt Linux server binary: $PrebuiltBinary"
+    Push-Location $RepoRoot
+    try {
+        docker build `
+            -f Minecraft.Server/docker/Dockerfile.prebuilt `
+            -t $Image `
+            .
+        if ($LASTEXITCODE -ne 0) { exit $LASTEXITCODE }
+    } finally {
+        Pop-Location
+    }
+}
+
+function Invoke-FullDockerBuild {
+    Push-Location $RepoRoot
+    try {
+        docker build `
+            -f Minecraft.Server/docker/Dockerfile `
+            --build-arg BUILD_JOBS=$BuildJobs `
+            -t $Image `
+            .
+        if ($LASTEXITCODE -ne 0) { exit $LASTEXITCODE }
+    } finally {
+        Pop-Location
+    }
+}
+
+function Try-DownloadGitHubBinary {
+    if ([string]::IsNullOrWhiteSpace($GitHubRepo)) {
+        return $false
+    }
+
+    $releasePath = if ([string]::IsNullOrWhiteSpace($GitHubReleaseTag) -or $GitHubReleaseTag -eq "latest") {
+        "latest"
+    } else {
+        "tags/$GitHubReleaseTag"
+    }
+
+    $releaseUrl = "https://api.github.com/repos/$GitHubRepo/releases/$releasePath"
+    Write-Host "Looking for GitHub release asset '$GitHubAssetName' at $releaseUrl"
+
+    try {
+        $headers = @{
+            Accept = "application/vnd.github+json"
+            "X-GitHub-Api-Version" = "2022-11-28"
+            "User-Agent" = "lcemp-docker-build"
+        }
+        $release = Invoke-RestMethod -Uri $releaseUrl -Headers $headers
+        $asset = $release.assets | Where-Object { $_.name -eq $GitHubAssetName } | Select-Object -First 1
+        if (-not $asset) {
+            Write-Host "GitHub release found, but asset '$GitHubAssetName' was not present."
+            return $false
+        }
+
+        $buildDir = Split-Path -Parent $PrebuiltBinary
+        New-Item -ItemType Directory -Force -Path $buildDir | Out-Null
+        Invoke-WebRequest -Uri $asset.browser_download_url -OutFile $PrebuiltBinary -Headers @{ "User-Agent" = "lcemp-docker-build" }
+        Write-Host "Downloaded Linux server binary from GitHub: $($asset.browser_download_url)"
+        return $true
+    } catch {
+        Write-Host "GitHub binary download failed: $($_.Exception.Message)"
+        return $false
+    }
+}
+
+if (-not $ForceFullBuild -and (Test-Path $PrebuiltBinary)) {
+    Invoke-DockerPrebuiltBuild
+} else {
+    if ($ForceFullBuild) {
+        Write-Host "ForceFullBuild set; running full Docker build."
+        Invoke-FullDockerBuild
+    } else {
+        Write-Host "No prebuilt Linux server binary found at: $PrebuiltBinary"
+        if (Try-DownloadGitHubBinary -and (Test-Path $PrebuiltBinary)) {
+            Invoke-DockerPrebuiltBuild
+        } else {
+            Write-Host "Running full Docker build."
+            Invoke-FullDockerBuild
+        }
+    }
+}
--- a/docker/build-image.sh
+++ b/docker/build-image.sh
@@ -0,0 +1,108 @@
+#!/bin/sh
+set -eu
+
+image="${IMAGE:-lcemp-server:local}"
+build_jobs="${BUILD_JOBS:-2}"
+force_full_build="${FORCE_FULL_BUILD:-false}"
+github_repo="${GITHUB_REPOSITORY:-}"
+github_release_tag="${GITHUB_RELEASE_TAG:-latest}"
+github_asset_name="${GITHUB_ASSET_NAME:-MinecraftDedicatedServer}"
+
+script_dir="$(cd "$(dirname "$0")" && pwd)"
+repo_root="$(cd "$script_dir/../.." && pwd)"
+prebuilt_binary="$repo_root/build/MinecraftDedicatedServer"
+
+build_prebuilt_image() {
+    echo "Using prebuilt Linux server binary: $prebuilt_binary"
+    cd "$repo_root"
+    docker build \
+        -f Minecraft.Server/docker/Dockerfile.prebuilt \
+        -t "$image" \
+        .
+}
+
+build_full_image() {
+    cd "$repo_root"
+    docker build \
+        -f Minecraft.Server/docker/Dockerfile \
+        --build-arg BUILD_JOBS="$build_jobs" \
+        -t "$image" \
+        .
+}
+
+try_download_github_binary() {
+    if [ -z "$github_repo" ]; then
+        return 1
+    fi
+
+    if [ "$github_release_tag" = "latest" ] || [ -z "$github_release_tag" ]; then
+        release_url="https://api.github.com/repos/$github_repo/releases/latest"
+    else
+        release_url="https://api.github.com/repos/$github_repo/releases/tags/$github_release_tag"
+    fi
+
+    if ! command -v python3 >/dev/null 2>&1; then
+        echo "python3 is required to download GitHub release assets from build-image.sh."
+        return 1
+    fi
+
+    echo "Looking for GitHub release asset '$github_asset_name' at $release_url"
+    mkdir -p "$(dirname "$prebuilt_binary")"
+
+    GITHUB_RELEASE_URL="$release_url" \
+    GITHUB_ASSET_NAME="$github_asset_name" \
+    PREBUILT_BINARY="$prebuilt_binary" \
+    python3 - <<'PY'
+import json
+import os
+import sys
+import urllib.request
+
+release_url = os.environ["GITHUB_RELEASE_URL"]
+asset_name = os.environ["GITHUB_ASSET_NAME"]
+prebuilt_binary = os.environ["PREBUILT_BINARY"]
+
+headers = {
+    "Accept": "application/vnd.github+json",
+    "X-GitHub-Api-Version": "2022-11-28",
+    "User-Agent": "lcemp-docker-build",
+}
+
+try:
+    req = urllib.request.Request(release_url, headers=headers)
+    with urllib.request.urlopen(req) as response:
+        release = json.load(response)
+
+    asset = next((item for item in release.get("assets", []) if item.get("name") == asset_name), None)
+    if asset is None:
+        print(f"GitHub release found, but asset '{asset_name}' was not present.")
+        sys.exit(1)
+
+    download_url = asset["browser_download_url"]
+    req = urllib.request.Request(download_url, headers={"User-Agent": "lcemp-docker-build"})
+    with urllib.request.urlopen(req) as response, open(prebuilt_binary, "wb") as output:
+        output.write(response.read())
+
+    print(f"Downloaded Linux server binary from GitHub: {download_url}")
+except Exception as exc:
+    print(f"GitHub binary download failed: {exc}")
+    sys.exit(1)
+PY
+}
+
+if [ "$force_full_build" != "true" ] && [ -f "$prebuilt_binary" ]; then
+    build_prebuilt_image
+else
+    if [ "$force_full_build" = "true" ]; then
+        echo "FORCE_FULL_BUILD=true; running full Docker build."
+        build_full_image
+    else
+        echo "No prebuilt Linux server binary found at: $prebuilt_binary"
+        if try_download_github_binary && [ -f "$prebuilt_binary" ]; then
+            build_prebuilt_image
+        else
+            echo "Running full Docker build."
+            build_full_image
+        fi
+    fi
+fi
--- a/docker/compose.prebuilt.yaml
+++ b/docker/compose.prebuilt.yaml
@@ -0,0 +1,4 @@
+services:
+  lcemp-server:
+    build:
+      dockerfile: Minecraft.Server/docker/Dockerfile.prebuilt
--- a/docker/compose.yaml
+++ b/docker/compose.yaml
@@ -0,0 +1,24 @@
+services:
+  lcemp-server:
+    build:
+      context: ../..
+      dockerfile: Minecraft.Server/docker/Dockerfile
+    image: lcemp-server:local
+    container_name: lcemp-server
+    restart: unless-stopped
+    network_mode: "host"
+    environment:
+      SERVER_PORT: "25565"
+      LEVEL_NAME: "world"
+      LEVEL_SIZE: "large"
+      GAMEMODE: "0"
+      DIFFICULTY: "2"
+      MAX_PLAYERS: "8"
+      PVP: "true"
+      MOTD: "A Minecraft LCE Server"
+      WHITE_LIST: "false"
+      VOICE_CHAT: "false"
+      ADVERTISE_LAN: "true"
+
+    volumes:
+      - ./config:/data
--- a/docker/entrypoint.sh
+++ b/docker/entrypoint.sh
@@ -0,0 +1,62 @@
+#!/bin/sh
+set -eu
+
+properties_file="${SERVER_PROPERTIES_FILE:-/data/server.properties}"
+
+SERVER_PORT="${SERVER_PORT:-25565}"
+SERVER_IP="${SERVER_IP:-}"
+LEVEL_NAME="${LEVEL_NAME:-world}"
+LEVEL_SEED="${LEVEL_SEED:-}"
+LEVEL_SIZE="${LEVEL_SIZE:-large}"
+GAMEMODE="${GAMEMODE:-0}"
+DIFFICULTY="${DIFFICULTY:-2}"
+MAX_PLAYERS="${MAX_PLAYERS:-8}"
+PVP="${PVP:-true}"
+TRUST_PLAYERS="${TRUST_PLAYERS:-true}"
+FIRE_SPREADS="${FIRE_SPREADS:-true}"
+TNT_EXPLODES="${TNT_EXPLODES:-true}"
+STRUCTURES="${STRUCTURES:-true}"
+SPAWN_ANIMALS="${SPAWN_ANIMALS:-true}"
+SPAWN_NPCS="${SPAWN_NPCS:-true}"
+ONLINE_MODE="${ONLINE_MODE:-false}"
+SHOW_GAMERTAGS="${SHOW_GAMERTAGS:-true}"
+MOTD="${MOTD:-A Minecraft LCE Server}"
+WHITE_LIST="${WHITE_LIST:-false}"
+VOICE_CHAT="${VOICE_CHAT:-false}"
+ENABLE_CHAT="${ENABLE_CHAT:-true}"
+ADVERTISE_LAN="${ADVERTISE_LAN:-true}"
+
+write_property() {
+    printf '%s=%s\n' "$1" "$2"
+}
+
+mkdir -p "$(dirname "$properties_file")"
+
+{
+    printf '#Minecraft server properties\n'
+    printf '#Generated from container environment on %s\n' "$(date -u '+%Y-%m-%dT%H:%M:%SZ')"
+    write_property server-port "$SERVER_PORT"
+    write_property level-name "$LEVEL_NAME"
+    write_property level-seed "$LEVEL_SEED"
+    write_property gamemode "$GAMEMODE"
+    write_property difficulty "$DIFFICULTY"
+    write_property max-players "$MAX_PLAYERS"
+    write_property pvp "$PVP"
+    write_property trust-players "$TRUST_PLAYERS"
+    write_property fire-spreads "$FIRE_SPREADS"
+    write_property tnt-explodes "$TNT_EXPLODES"
+    write_property structures "$STRUCTURES"
+    write_property spawn-animals "$SPAWN_ANIMALS"
+    write_property spawn-npcs "$SPAWN_NPCS"
+    write_property online-mode "$ONLINE_MODE"
+    write_property show-gamertags "$SHOW_GAMERTAGS"
+    write_property motd "$MOTD"
+    write_property white-list "$WHITE_LIST"
+    write_property voice-chat "$VOICE_CHAT"
+    write_property enable-chat "$ENABLE_CHAT"
+    write_property level-size "$LEVEL_SIZE"
+    write_property advertise-lan "$ADVERTISE_LAN"
+    write_property server-ip "$SERVER_IP"
+} > "$properties_file"
+
+exec "$@"