Add Compatibility Mode (#43)

Adds a compatibility mode option to prevent crashes and disconnections by bringing behavior closer in line with the vanilla client. Closes #41; Closes #34; Closes #33; and Closes #30.
CloudburstMC · Jul 8, 2024 · bcf0bbd · bcf0bbd
2 parents f408c9a + 5f13c77
commit bcf0bbd
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Showing 14 changed files with 240 additions and 28 deletions.
diff --git a/build.gradle.kts b/build.gradle.kts
@@ -102,6 +102,9 @@ subprojects {
             options.encoding = "UTF-8"
         }
         named<Test>("test") {
+            minHeapSize = "512m"
+            maxHeapSize = "1024m"
+            jvmArgs = listOf("-XX:MaxMetaspaceSize=512m")
             useJUnitPlatform()
         }
     }

diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
@@ -8,6 +8,7 @@ netty-common = { group = "io.netty", name = "netty-common", version.ref = "netty
 netty-buffer = { group = "io.netty", name = "netty-buffer", version.ref = "netty" }
 netty-codec = { group = "io.netty", name = "netty-codec", version.ref = "netty" }
 netty-transport = { group = "io.netty", name = "netty-transport", version.ref = "netty" }
+netty-transport-native-unix-common = { group = "io.netty", name = "netty-transport-native-unix-common", version.ref = "netty" }
 
 expiringmap = { group = "net.jodah", name = "expiringmap", version = "0.5.10" }
 
@@ -18,6 +19,8 @@ junit-jupiter-params = { group = "org.junit.jupiter", name = "junit-jupiter-para
 
 
 [bundles]
+netty = [ "netty-common", "netty-buffer", "netty-codec", "netty-transport", "netty-transport-native-unix-common" ]
+junit = [ "junit-jupiter-engine", "junit-jupiter-api", "junit-jupiter-params" ]
 
 
 [plugins]

diff --git a/transport-raknet/build.gradle.kts b/transport-raknet/build.gradle.kts
@@ -17,15 +17,10 @@
 description = "RakNet transport for Netty"
 
 dependencies {
-    api(libs.netty.common)
-    api(libs.netty.buffer)
-    api(libs.netty.codec)
-    api(libs.netty.transport)
+    api(libs.bundles.netty)
     api(libs.expiringmap)
 
-    testImplementation(libs.junit.jupiter.engine)
-    testImplementation(libs.junit.jupiter.api)
-    testImplementation(libs.junit.jupiter.params)
+    testImplementation(libs.bundles.junit)
 }
 
 tasks.jar {

diff --git a/transport-raknet/src/main/java/org/cloudburstmc/netty/channel/raknet/RakClientChannel.java b/transport-raknet/src/main/java/org/cloudburstmc/netty/channel/raknet/RakClientChannel.java
@@ -20,6 +20,8 @@
 import io.netty.channel.ChannelPipeline;
 import io.netty.channel.ChannelPromise;
 import io.netty.channel.socket.DatagramChannel;
+import io.netty.util.internal.logging.InternalLogger;
+import io.netty.util.internal.logging.InternalLoggerFactory;
 import org.cloudburstmc.netty.channel.proxy.ProxyChannel;
 import org.cloudburstmc.netty.channel.raknet.config.DefaultRakClientConfig;
 import org.cloudburstmc.netty.channel.raknet.config.RakChannelConfig;
@@ -30,6 +32,7 @@
 
 public class RakClientChannel extends ProxyChannel<DatagramChannel> implements RakChannel {
 
+    private static final InternalLogger log = InternalLoggerFactory.getInstance(RakClientChannel.class);
     private static final ChannelMetadata metadata = new ChannelMetadata(true);
 
     /**
@@ -41,6 +44,7 @@ public class RakClientChannel extends ProxyChannel<DatagramChannel> implements R
     public RakClientChannel(DatagramChannel channel) {
         super(channel);
         this.config = new DefaultRakClientConfig(this);
+
         this.pipeline().addLast(RakClientRouteHandler.NAME, new RakClientRouteHandler(this));
         // Transforms DatagramPacket to ByteBuf if channel has been already connected
         this.rakPipeline().addFirst(RakClientProxyRouteHandler.NAME, new RakClientProxyRouteHandler(this));

diff --git a/transport-raknet/src/main/java/org/cloudburstmc/netty/channel/raknet/RakConstants.java b/transport-raknet/src/main/java/org/cloudburstmc/netty/channel/raknet/RakConstants.java
@@ -28,6 +28,7 @@ public class RakConstants {
     public static final byte RAKNET_PROTOCOL_VERSION = 11; // Mojang's version.
     public static final int MINIMUM_MTU_SIZE = 576;
     public static final int MAXIMUM_MTU_SIZE = 1400;
+    public static final Integer[] MTU_SIZES = new Integer[]{MAXIMUM_MTU_SIZE, 1200, MINIMUM_MTU_SIZE};
     /**
      * Maximum amount of ordering channels as defined in vanilla RakNet.
      */

diff --git a/...et/src/main/java/org/cloudburstmc/netty/channel/raknet/config/DefaultRakClientConfig.java b/...et/src/main/java/org/cloudburstmc/netty/channel/raknet/config/DefaultRakClientConfig.java
@@ -20,10 +20,12 @@
 import io.netty.buffer.Unpooled;
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelOption;
+import org.cloudburstmc.netty.util.IpDontFragmentProvider;
 
 import java.util.Map;
 
 import static org.cloudburstmc.netty.channel.raknet.RakConstants.DEFAULT_UNCONNECTED_MAGIC;
+import static org.cloudburstmc.netty.channel.raknet.RakConstants.MTU_SIZES;
 import static org.cloudburstmc.netty.channel.raknet.RakConstants.SESSION_TIMEOUT_MS;
 
 /**
@@ -35,14 +37,21 @@ public class DefaultRakClientConfig extends DefaultRakSessionConfig {
     private volatile long connectTimeout = SESSION_TIMEOUT_MS;
     private volatile long sessionTimeout = SESSION_TIMEOUT_MS;
     private volatile long serverGuid;
+    private volatile boolean compatibilityMode = false;
+    private volatile Integer[] mtuSizes = MTU_SIZES;
+    private volatile boolean ipDontFragment = false;
+    private volatile int clientInternalAddresses = 10;
 
     public DefaultRakClientConfig(Channel channel) {
         super(channel);
     }
 
     @Override
     public Map<ChannelOption<?>, Object> getOptions() {
-        return this.getOptions(super.getOptions(), RakChannelOption.RAK_UNCONNECTED_MAGIC, RakChannelOption.RAK_CONNECT_TIMEOUT, RakChannelOption.RAK_REMOTE_GUID, RakChannelOption.RAK_SESSION_TIMEOUT);
+        return this.getOptions(
+            super.getOptions(), 
+            RakChannelOption.RAK_UNCONNECTED_MAGIC, RakChannelOption.RAK_CONNECT_TIMEOUT, RakChannelOption.RAK_REMOTE_GUID, RakChannelOption.RAK_SESSION_TIMEOUT, RakChannelOption.RAK_COMPATIBILITY_MODE,
+            RakChannelOption.RAK_MTU_SIZES, RakChannelOption.RAK_IP_DONT_FRAGMENT, RakChannelOption.RAK_CLIENT_INTERNAL_ADDRESSES);
     }
 
     @SuppressWarnings("unchecked")
@@ -56,6 +65,14 @@ public <T> T getOption(ChannelOption<T> option) {
             return (T) Long.valueOf(this.getServerGuid());
         } else if (option == RakChannelOption.RAK_SESSION_TIMEOUT) {
             return (T) Long.valueOf(this.getSessionTimeout());
+        } else if (option == RakChannelOption.RAK_COMPATIBILITY_MODE) {
+            return (T) Boolean.valueOf(this.isCompatibilityMode());
+        } else if (option == RakChannelOption.RAK_MTU_SIZES) {
+            return (T) this.getMtuSizes();
+        } else if (option == RakChannelOption.RAK_IP_DONT_FRAGMENT) {
+            return (T) Boolean.valueOf(this.ipDontFragment);
+        } else if (option == RakChannelOption.RAK_CLIENT_INTERNAL_ADDRESSES) {
+            return (T) Integer.valueOf(this.clientInternalAddresses);
         }
         return super.getOption(option);
     }
@@ -76,6 +93,18 @@ public <T> boolean setOption(ChannelOption<T> option, T value) {
         } else if (option == RakChannelOption.RAK_SESSION_TIMEOUT) {
             this.setSessionTimeout((Long) value);
             return true;
+        } else if (option == RakChannelOption.RAK_COMPATIBILITY_MODE) {
+            this.setCompatibilityMode((Boolean) value);
+            return true;
+        } else if (option == RakChannelOption.RAK_MTU_SIZES) {
+            this.setMtuSizes((Integer[]) value);
+            return true;
+        } else if (option == RakChannelOption.RAK_IP_DONT_FRAGMENT) {
+            this.setIpDontFragment((Boolean) value);
+            return (Boolean) value == this.isIpDontFragment();
+        } else if (option == RakChannelOption.RAK_CLIENT_INTERNAL_ADDRESSES) {
+            this.setClientInternalAddresses((Integer) value);
+            return true;
         }
         return super.setOption(option, value);
     }
@@ -120,4 +149,36 @@ public RakChannelConfig setSessionTimeout(long timeout) {
     public long getSessionTimeout() {
         return this.sessionTimeout;
     }
+
+    public boolean isCompatibilityMode() {
+        return this.compatibilityMode;
+    }
+
+    public void setCompatibilityMode(boolean enable) {
+        this.compatibilityMode = enable;
+    }
+
+    public Integer[] getMtuSizes() {
+        return this.mtuSizes.clone();
+    }
+
+    public void setMtuSizes(Integer[] mtuSizes) {
+        this.mtuSizes = mtuSizes.clone();
+    }
+
+    public boolean isIpDontFragment() {
+        return this.ipDontFragment;
+    }
+
+    public void setIpDontFragment(boolean enable) {
+        this.ipDontFragment = IpDontFragmentProvider.trySet(this.channel, enable);
+    }
+
+    public int getClientInternalAddresses() {
+        return this.clientInternalAddresses;
+    }
+
+    public void setClientInternalAddresses(int clientInternalAddresses) {
+        this.clientInternalAddresses = clientInternalAddresses;
+    }
 }
diff --git a/...et/src/main/java/org/cloudburstmc/netty/channel/raknet/config/DefaultRakServerConfig.java b/...et/src/main/java/org/cloudburstmc/netty/channel/raknet/config/DefaultRakServerConfig.java
@@ -22,6 +22,7 @@
 import io.netty.channel.DefaultChannelConfig;
 import org.cloudburstmc.netty.channel.raknet.RakConstants;
 import org.cloudburstmc.netty.channel.raknet.RakServerChannel;
+import org.cloudburstmc.netty.util.IpDontFragmentProvider;
 
 import java.util.Arrays;
 import java.util.Map;
@@ -47,6 +48,8 @@ public class DefaultRakServerConfig extends DefaultChannelConfig implements RakS
     private volatile int globalPacketLimit = RakConstants.DEFAULT_GLOBAL_PACKET_LIMIT;
     private volatile RakServerMetrics metrics;
     private volatile boolean sendCookie;
+    private volatile boolean ipDontFragment = false;
+
 
     public DefaultRakServerConfig(RakServerChannel channel) {
         super(channel);
@@ -58,7 +61,7 @@ public Map<ChannelOption<?>, Object> getOptions() {
                 super.getOptions(),
                 RakChannelOption.RAK_GUID, RakChannelOption.RAK_MAX_CHANNELS, RakChannelOption.RAK_MAX_CONNECTIONS, RakChannelOption.RAK_SUPPORTED_PROTOCOLS, RakChannelOption.RAK_UNCONNECTED_MAGIC,
                 RakChannelOption.RAK_ADVERTISEMENT, RakChannelOption.RAK_HANDLE_PING, RakChannelOption.RAK_PACKET_LIMIT, RakChannelOption.RAK_GLOBAL_PACKET_LIMIT, RakChannelOption.RAK_SEND_COOKIE,
-                RakChannelOption.RAK_SERVER_METRICS);
+                RakChannelOption.RAK_SERVER_METRICS, RakChannelOption.RAK_IP_DONT_FRAGMENT);
     }
 
     @SuppressWarnings("unchecked")
@@ -103,6 +106,9 @@ public <T> T getOption(ChannelOption<T> option) {
         if (option == RakChannelOption.RAK_SEND_COOKIE) {
             return (T) Boolean.valueOf(this.sendCookie);
         }
+        if (option == RakChannelOption.RAK_IP_DONT_FRAGMENT) {
+            return (T) Boolean.valueOf(this.ipDontFragment);
+        }
         return this.channel.parent().config().getOption(option);
     }
 
@@ -133,10 +139,13 @@ public <T> boolean setOption(ChannelOption<T> option, T value) {
         } else if (option == RakChannelOption.RAK_GLOBAL_PACKET_LIMIT) {
             this.setGlobalPacketLimit((Integer) value);
         } else if (option == RakChannelOption.RAK_SEND_COOKIE) {
-            this.sendCookie = (Boolean) value;
+            this.setSendCookie((Boolean) value);
         } else if (option == RakChannelOption.RAK_SERVER_METRICS) {
             this.setMetrics((RakServerMetrics) value);
-        } else{
+        } else if (option == RakChannelOption.RAK_IP_DONT_FRAGMENT) {
+            this.setIpDontFragment((Boolean) value);
+            return (Boolean) value == this.getIpDontFragment();
+        } else {
             return this.channel.parent().config().setOption(option, value);
         }
         return true;
@@ -291,4 +300,14 @@ public void setMetrics(RakServerMetrics metrics) {
     public RakServerMetrics getMetrics() {
         return this.metrics;
     }
+
+    @Override
+    public void setIpDontFragment(boolean ipDontFragment) {
+        this.ipDontFragment = IpDontFragmentProvider.trySet(this.channel.parent(), ipDontFragment);
+    }
+
+    @Override
+    public boolean getIpDontFragment() {
+        return this.ipDontFragment;
+    }
 }
diff --git a/...t-raknet/src/main/java/org/cloudburstmc/netty/channel/raknet/config/RakChannelOption.java b/...t-raknet/src/main/java/org/cloudburstmc/netty/channel/raknet/config/RakChannelOption.java
@@ -152,12 +152,36 @@ public class RakChannelOption<T> extends ChannelOption<T> {
     public static final ChannelOption<Integer> RAK_GLOBAL_PACKET_LIMIT =
             valueOf(RakChannelOption.class, "RAK_GLOBAL_PACKET_LIMIT");
 
+    /**
+     * Whether the client should be run in compatibility mode for closer behavior to the vanilla client RakNet implementation.
+     */
+    public static final ChannelOption<Boolean> RAK_COMPATIBILITY_MODE =
+            valueOf(RakChannelOption.class, "RAK_COMPATIBILITY_MODE");
+
     /**
      * Whether to send a cookie to the client during the connection process.
      */
     public static final ChannelOption<Boolean> RAK_SEND_COOKIE =
             valueOf(RakChannelOption.class, "RAK_SEND_COOKIE");
 
+    /**
+     * An array of MTU sizes that the RakNet client will use when initially connecting.
+     */
+    public static final ChannelOption<Integer[]> RAK_MTU_SIZES =
+            valueOf(RakChannelOption.class, "RAK_MTU_SIZES");
+
+    /**
+     * Whether to use the IP_DONT_FRAGMENT option for the client channel.
+     */
+    public static final ChannelOption<Boolean> RAK_IP_DONT_FRAGMENT =
+            valueOf(RakChannelOption.class, "RAK_IP_DONT_FRAGMENT");
+
+    /**
+     * The amount of internal addresses to send from the client in New Incoming Connection packets.
+     */
+    public static final ChannelOption<Integer> RAK_CLIENT_INTERNAL_ADDRESSES =
+            valueOf(RakChannelOption.class, "RAK_CLIENT_INTERNAL_ADDRESSES");
+
     @SuppressWarnings("deprecation")
     protected RakChannelOption() {
         super(null);

diff --git a/...et/src/main/java/org/cloudburstmc/netty/channel/raknet/config/RakServerChannelConfig.java b/...et/src/main/java/org/cloudburstmc/netty/channel/raknet/config/RakServerChannelConfig.java
@@ -72,4 +72,8 @@ public interface RakServerChannelConfig extends ChannelConfig {
     void setMetrics(RakServerMetrics metrics);
 
     RakServerMetrics getMetrics();
+
+    void setIpDontFragment(boolean ipDontFragment);
+
+    boolean getIpDontFragment();
 }
diff --git a/...main/java/org/cloudburstmc/netty/handler/codec/raknet/client/RakClientOfflineHandler.java b/...main/java/org/cloudburstmc/netty/handler/codec/raknet/client/RakClientOfflineHandler.java
@@ -43,7 +43,7 @@ public class RakClientOfflineHandler extends SimpleChannelInboundHandler<ByteBuf
     private ScheduledFuture<?> retryFuture;
 
     private RakOfflineState state = RakOfflineState.HANDSHAKE_1;
-    private int connectionAttempts;
+    private int connectionAttempts = 0;
     private int cookie;
     private boolean security;
 
@@ -169,7 +169,11 @@ private void onOpenConnectionReply1(ChannelHandlerContext ctx, ByteBuf buffer) {
 
     private void onOpenConnectionReply2(ChannelHandlerContext ctx, ByteBuf buffer) {
         buffer.readLong(); // serverGuid
-        RakUtils.readAddress(buffer); // serverAddress
+        if (this.rakChannel.config().getOption(RakChannelOption.RAK_COMPATIBILITY_MODE)) {
+            RakUtils.skipAddress(buffer); // serverAddress
+        } else {
+            RakUtils.readAddress(buffer); // serverAddress
+        }
         int mtu = buffer.readShort();
         boolean security = buffer.readBoolean(); // security
         if (security) {
@@ -182,11 +186,8 @@ private void onOpenConnectionReply2(ChannelHandlerContext ctx, ByteBuf buffer) {
     }
 
     private void sendOpenConnectionRequest1(Channel channel) {
-        int mtuDiff = (MAXIMUM_MTU_SIZE - MINIMUM_MTU_SIZE) / 9;
-        int mtuSize = this.rakChannel.config().getOption(RakChannelOption.RAK_MTU) - (this.connectionAttempts * mtuDiff);
-        if (mtuSize < MINIMUM_MTU_SIZE) {
-            mtuSize = MINIMUM_MTU_SIZE;
-        }
+        int mtuSizeIndex = Math.min(this.connectionAttempts / 4, this.rakChannel.config().getOption(RakChannelOption.RAK_MTU_SIZES).length - 1);
+        int mtuSize = this.rakChannel.config().getOption(RakChannelOption.RAK_MTU_SIZES)[mtuSizeIndex];
 
         ByteBuf magicBuf = this.rakChannel.config().getOption(RakChannelOption.RAK_UNCONNECTED_MAGIC);
         int rakVersion = this.rakChannel.config().getOption(RakChannelOption.RAK_PROTOCOL_VERSION);

diff --git a/...ava/org/cloudburstmc/netty/handler/codec/raknet/client/RakClientOnlineInitialHandler.java b/...ava/org/cloudburstmc/netty/handler/codec/raknet/client/RakClientOnlineInitialHandler.java
@@ -90,28 +90,34 @@ protected void channelRead0(ChannelHandlerContext ctx, EncapsulatedPacket messag
 
     private void onConnectionRequestAccepted(ChannelHandlerContext ctx, ByteBuf buf) {
         buf.skipBytes(1);
-        RakUtils.readAddress(buf); // Client address
+
+        boolean compatibilityMode = this.rakChannel.config().getOption(RakChannelOption.RAK_COMPATIBILITY_MODE);
+        if (compatibilityMode) {
+            RakUtils.skipAddress(buf); // Client address
+        } else {
+            RakUtils.readAddress(buf); // Client address
+        }
+
         buf.readUnsignedShort(); // System index
 
         // Address + 2 * Long - Minimum amount of data
         int required = IPV4_MESSAGE_SIZE + 16;
-        int count = 0;
+
         long pingTime = 0;
-        try {
-            while (buf.isReadable(required)) {
+        while (buf.isReadable(required)) {
+            if (compatibilityMode) {
+                RakUtils.skipAddress(buf);
+            } else {
                 RakUtils.readAddress(buf);
-                count++;
             }
-            pingTime = buf.readLong();
-            buf.readLong();
-        } catch (IndexOutOfBoundsException ignored) {
-            // Hive sends malformed IPv6 address
         }
+        pingTime = buf.readLong();
+        buf.readLong();
 
         ByteBuf buffer = ctx.alloc().ioBuffer();
         buffer.writeByte(ID_NEW_INCOMING_CONNECTION);
         RakUtils.writeAddress(buffer, (InetSocketAddress) ctx.channel().remoteAddress());
-        for (int i = 0; i < count; i++) {
+        for (int i = 0; i < this.rakChannel.config().getOption(RakChannelOption.RAK_CLIENT_INTERNAL_ADDRESSES); i++) {
             RakUtils.writeAddress(buffer, LOCAL_ADDRESS);
         }
         buffer.writeLong(pingTime);