Merge branch 'dev/1.1.0' into dev/2.0.0

# Conflicts:
#	api/build.gradle
#	api/src/main/java/com/velocitypowered/api/proxy/connection/Player.java
#	api/src/main/java/com/velocitypowered/api/proxy/player/TabList.java
#	build.gradle
#	proxy/build.gradle
#	proxy/src/main/java/com/velocitypowered/proxy/Velocity.java
#	proxy/src/main/java/com/velocitypowered/proxy/command/CommandNodeFactory.java
#	proxy/src/main/java/com/velocitypowered/proxy/connection/backend/BackendPlaySessionHandler.java
#	proxy/src/main/java/com/velocitypowered/proxy/connection/backend/BungeeCordMessageResponder.java
#	proxy/src/main/java/com/velocitypowered/proxy/connection/backend/VelocityServerConnection.java
#	proxy/src/main/java/com/velocitypowered/proxy/connection/client/ConnectedPlayer.java
#	proxy/src/main/java/com/velocitypowered/proxy/network/packet/clientbound/ClientboundAvailableCommandsPacket.java
#	proxy/src/main/java/com/velocitypowered/proxy/network/packet/clientbound/ClientboundJoinGamePacket.java
#	proxy/src/main/java/com/velocitypowered/proxy/network/packet/clientbound/ClientboundRespawnPacket.java
#	proxy/src/main/java/com/velocitypowered/proxy/network/pipeline/MinecraftDecoder.java
#	proxy/src/main/java/com/velocitypowered/proxy/protocol/MinecraftPacket.java
#	proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/EncryptionResponse.java
#	proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/HeaderAndFooter.java
#	proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/LoginPluginMessage.java
#	proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/PluginMessage.java
#	proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/ServerLogin.java
#	proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/StatusPing.java
#	proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/StatusRequest.java
#	proxy/src/main/java/com/velocitypowered/proxy/tablist/VelocityTabList.java
#	proxy/src/main/java/com/velocitypowered/proxy/tablist/VelocityTabListLegacy.java
#	proxy/src/test/java/com/velocitypowered/proxy/command/CommandManagerTests.java

.github/workflows/gradle.yml

@@ -0,0 +1,32 @@
+# This workflow will build a Java project with Gradle
+# For more information see: https://help.github.com/actions/language-and-framework-guides/building-and-testing-java-with-gradle
+
+name: Java CI with Gradle
+
+on: [push, pull_request]
+
+jobs:
+  build-8:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up JDK 1.8
+      uses: actions/setup-java@v1
+      with:
+        java-version: 1.8
+    - name: Grant execute permission for gradlew
+      run: chmod +x gradlew
+    - name: Build with Gradle
+      run: ./gradlew build
+  build-11:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up JDK 11
+      uses: actions/setup-java@v1
+      with:
+        java-version: 11
+    - name: Grant execute permission for gradlew
+      run: chmod +x gradlew
+    - name: Build with Gradle
+      run: ./gradlew build

CONTRIBUTING.md

@@ -28,9 +28,7 @@ sure that you are properly adhering to the code style.
 To reduce bugs and ensure code quality, we run the following tools on all commits
 and pull requests:
 
-* [Checker Framework](https://checkerframework.org/): an enhancement to Java's type
+* [SpotBugs](https://spotbugs.github.io/): ensures that common errors do not
-  system that is designed to help catch bugs. Velocity runs the _Nullness Checker_
+  get into the codebase. The build will fail if SpotBugs finds an issue.
-  and the _Optional Checker_. The build will fail if Checker Framework notices an
-  issue.
 * [Checkstyle](http://checkstyle.sourceforge.net/): ensures that your code is
   correctly formatted. The build will fail if Checkstyle detects a problem.

api/build.gradle

@@ -84,6 +84,15 @@ javadoc {
 
     // Mark sources as Java 8 source compatible
     options.source = '8'
+
+    // Remove 'undefined' from seach paths when generating javadoc for a non-modular project (JDK-8215291)
+    if (JavaVersion.current() >= JavaVersion.VERSION_1_9 && JavaVersion.current() < JavaVersion.VERSION_12) {
+        options.addBooleanOption('-no-module-directories', true)
+    }
+}
+
+test {
+    useJUnitPlatform()
 }
 
 test {

api/src/main/java/com/velocitypowered/api/event/player/PlayerChannelRegisterEvent.java

@@ -0,0 +1,38 @@
+package com.velocitypowered.api.event.player;
+
+import com.google.common.base.Preconditions;
+import com.velocitypowered.api.proxy.Player;
+import com.velocitypowered.api.proxy.messages.ChannelIdentifier;
+
+import java.util.List;
+
+/**
+ * This event is fired when a client ({@link Player}) sends a plugin message through the
+ * register channel.
+ */
+public final class PlayerChannelRegisterEvent {
+
+  private final Player player;
+  private final List<ChannelIdentifier> channels;
+
+  public PlayerChannelRegisterEvent(Player player, List<ChannelIdentifier> channels) {
+    this.player = Preconditions.checkNotNull(player, "player");
+    this.channels = Preconditions.checkNotNull(channels, "channels");
+  }
+
+  public Player getPlayer() {
+    return player;
+  }
+
+  public List<ChannelIdentifier> getChannels() {
+    return channels;
+  }
+
+  @Override
+  public String toString() {
+    return "PlayerChannelRegisterEvent{"
+            + "player=" + player
+            + ", channels=" + channels
+            + '}';
+  }
+}

api/src/main/java/com/velocitypowered/api/proxy/messages/MinecraftChannelIdentifier.java

@@ -12,7 +12,7 @@ import org.checkerframework.checker.nullness.qual.Nullable;
  */
 public final class MinecraftChannelIdentifier implements ChannelIdentifier {
 
-  private static final Pattern VALID_IDENTIFIER_REGEX = Pattern.compile("[a-z0-9\\-_]*");
+  private static final Pattern VALID_IDENTIFIER_REGEX = Pattern.compile("[a-z0-9/\\-_]*");
 
   private final String namespace;
   private final String name;

api/src/main/java/com/velocitypowered/api/proxy/server/ServerPing.java

@@ -227,6 +227,11 @@ public final class ServerPing {
       return this;
     }
 
+    public Builder clearFavicon() {
+      this.favicon = null;
+      return this;
+    }
+
     /**
      * Uses the information from this builder to create a new {@link ServerPing} instance. The
      * builder can be re-used after this event has been called.

api/src/test/java/com/velocitypowered/api/proxy/messages/MinecraftChannelIdentifierTest.java

@@ -35,6 +35,11 @@ class MinecraftChannelIdentifierTest {
     assertEquals(expected, MinecraftChannelIdentifier.from("velocity:test"));
   }
 
+  @Test
+  void createAllowsSlashes() {
+    create("velocity", "test/test2");
+  }
+
   @Test
   void fromIdentifierThrowsOnBadValues() {
     assertAll(

build.gradle

@@ -20,11 +20,11 @@ allprojects {
 
     ext {
         // dependency versions
-        adventureVersion = '4.1.1'
+        adventureVersion = '4.5.0'
         junitVersion = '5.7.0'
         slf4jVersion = '1.7.30'
         log4jVersion = '2.13.3'
-        nettyVersion = '4.1.56.Final'
+        nettyVersion = '4.1.59.Final'
         guavaVersion = '30.0-jre'
         checkerFrameworkVersion = '3.6.1'
         configurateVersion = '4.0.0-SNAPSHOT'

proxy/build.gradle

@@ -55,13 +55,13 @@ dependencies {
     implementation "io.netty:netty-handler:${nettyVersion}"
     implementation "io.netty:netty-transport-native-epoll:${nettyVersion}"
     implementation "io.netty:netty-transport-native-epoll:${nettyVersion}:linux-x86_64"
-    implementation "io.netty:netty-transport-native-epoll:${nettyVersion}:linux-aarch64"
+    implementation "io.netty:netty-transport-native-epoll:${nettyVersion}:linux-aarch_64"
-    implementation "io.netty:netty-resolver-dns:${nettyVersion}"
 
     implementation "org.apache.logging.log4j:log4j-api:${log4jVersion}"
     implementation "org.apache.logging.log4j:log4j-core:${log4jVersion}"
     implementation "org.apache.logging.log4j:log4j-slf4j-impl:${log4jVersion}"
     implementation "org.apache.logging.log4j:log4j-iostreams:${log4jVersion}"
+    implementation "org.apache.logging.log4j:log4j-jul:${log4jVersion}"
 
     implementation 'net.sf.jopt-simple:jopt-simple:5.0.4' // command-line options
     implementation 'net.minecrell:terminalconsoleappender:1.2.0'
@@ -76,7 +76,7 @@ dependencies {
     implementation 'com.spotify:completable-futures:0.3.3'
 
     implementation 'com.electronwill.night-config:toml:3.6.3'
-
+    implementation 'org.bstats:bstats-base:2.2.0'
     implementation 'org.lanternpowered:lmbda:2.0.0-SNAPSHOT'
 
     implementation 'com.github.ben-manes.caffeine:caffeine:2.8.8'
@@ -117,7 +117,6 @@ shadowJar {
     exclude 'it/unimi/dsi/fastutil/objects/*Object2Float*'
     exclude 'it/unimi/dsi/fastutil/objects/*Object2IntArray*'
     exclude 'it/unimi/dsi/fastutil/objects/*Object2IntAVL*'
-    exclude 'it/unimi/dsi/fastutil/objects/*Object*OpenCustom*'
     exclude 'it/unimi/dsi/fastutil/objects/*Object2IntRB*'
     exclude 'it/unimi/dsi/fastutil/objects/*Object2Long*'
     exclude 'it/unimi/dsi/fastutil/objects/*Object2Object*'
@@ -127,12 +126,10 @@ shadowJar {
     exclude 'it/unimi/dsi/fastutil/objects/*Reference*'
     exclude 'it/unimi/dsi/fastutil/shorts/**'
     exclude 'org/checkerframework/checker/**'
+
+    relocate 'org.bstats', 'com.velocitypowered.proxy.bstats'
 }
 
 artifacts {
     archives shadowJar
 }
-
-test {
-    useJUnitPlatform()
-}

proxy/src/main/java/com/velocitypowered/proxy/Metrics.java

@@ -1,82 +1,67 @@
 package com.velocitypowered.proxy;
 
-import com.google.gson.JsonArray;
-import com.google.gson.JsonObject;
 import com.velocitypowered.proxy.config.VelocityConfiguration;
-import io.netty.handler.codec.http.HttpHeaderNames;
+
-import java.io.BufferedWriter;
+import java.io.File;
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
-import java.io.OutputStreamWriter;
+import java.nio.file.Paths;
-import java.io.Writer;
-import java.nio.charset.StandardCharsets;
-import java.util.ArrayList;
 import java.util.HashMap;
-import java.util.List;
 import java.util.Map;
-import java.util.Timer;
-import java.util.TimerTask;
-import java.util.concurrent.Callable;
-import java.util.concurrent.ExecutionException;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
-import java.util.zip.GZIPOutputStream;
+
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.asynchttpclient.ListenableFuture;
+import org.bstats.MetricsBase;
-import org.asynchttpclient.Response;
+import org.bstats.charts.CustomChart;
+import org.bstats.charts.DrilldownPie;
+import org.bstats.charts.SimplePie;
+import org.bstats.charts.SingleLineChart;
+import org.bstats.config.MetricsConfig;
+import org.bstats.json.JsonObjectBuilder;
 
-/**
- * bStats collects some data for plugin authors.
- * <p/>
- * Check out https://bStats.org/ to learn more about bStats!
- */
 public class Metrics {
 
-  // The version of this bStats class
+  private MetricsBase metricsBase;
-  private static final int B_STATS_METRICS_REVISION = 2;
 
-  // The url to which the data is sent
+  private Metrics(Logger logger, int serviceId, boolean defaultEnabled) {
-  private static final String URL = "https://bstats.org/submitData/server-implementation";
+    File configFile = Paths.get("plugins").resolve("bStats").resolve("config.txt").toFile();
+    MetricsConfig config;
+    try {
+      config = new MetricsConfig(configFile, defaultEnabled);
+    } catch (IOException e) {
+      logger.error("Failed to create bStats config", e);
+      return;
+    }
 
-  // The logger for the failed requests
+    metricsBase = new MetricsBase(
-  private static final Logger logger = LogManager.getLogger(Metrics.class);
+        "server-implementation",
+        config.getServerUUID(),
+        serviceId,
+        config.isEnabled(),
+        this::appendPlatformData,
+        jsonObjectBuilder -> { /* NOP */ },
+        null,
+        () -> true,
+        logger::warn,
+        logger::info,
+        config.isLogErrorsEnabled(),
+        config.isLogSentDataEnabled(),
+        config.isLogResponseStatusTextEnabled()
+    );
 
-  // Should failed requests be logged?
+    if (!config.didExistBefore()) {
-  private boolean logFailedRequests = false;
+      // Send an info message when the bStats config file gets created for the first time
-
+      logger.info("Velocity and some of its plugins collect metrics"
-  // The name of the server software
+          + " and send them to bStats (https://bStats.org).");
-  private final String name;
+      logger.info("bStats collects some basic information for plugin"
-
+          + " authors, like how many people use");
-  // The plugin ID for the server software as assigned by bStats.
+      logger.info("their plugin and their total player count."
-  private final int pluginId;
+          + " It's recommended to keep bStats enabled, but");
-
+      logger.info("if you're not comfortable with this, you can opt-out"
-  // The uuid of the server
+          + " by editing the config.txt file in");
-  private final String serverUuid;
+      logger.info("the '/plugins/bStats/' folder and setting enabled to false.");
-
+    }
-  // A list with all custom charts
-  private final List<CustomChart> charts = new ArrayList<>();
-
-  private final VelocityServer server;
-
-  /**
-   * Class constructor.
-   * @param name              The name of the server software.
-   * @param pluginId          The plugin ID for the server software as assigned by bStats.
-   * @param serverUuid        The uuid of the server.
-   * @param logFailedRequests Whether failed requests should be logged or not.
-   * @param server            The Velocity server instance.
-   */
-  private Metrics(String name, int pluginId, String serverUuid, boolean logFailedRequests,
-      VelocityServer server) {
-    this.name = name;
-    this.pluginId = pluginId;
-    this.serverUuid = serverUuid;
-    this.logFailedRequests = logFailedRequests;
-    this.server = server;
-
-    // Start submitting the data
-    startSubmitting();
   }
 
   /**
@@ -85,511 +70,37 @@ public class Metrics {
    * @param chart The chart to add.
    */
   public void addCustomChart(CustomChart chart) {
-    if (chart == null) {
+    metricsBase.addCustomChart(chart);
-      throw new IllegalArgumentException("Chart cannot be null!");
-    }
-    charts.add(chart);
-  }
-
-  /**
-   * Starts the Scheduler which submits our data every 30 minutes.
-   */
-  private void startSubmitting() {
-    final Timer timer = new Timer(true);
-    timer.scheduleAtFixedRate(new TimerTask() {
-      @Override
-      public void run() {
-        submitData();
-      }
-    }, 1000, 1000 * 60 * 30);
-    // Submit the data every 30 minutes, first time after 5 minutes to give other plugins enough
-    // time to start.
-    //
-    // WARNING: Changing the frequency has no effect but your plugin WILL be blocked/deleted!
-    // WARNING: Just don't do it!
-  }
-
-  /**
-   * Gets the plugin specific data.
-   *
-   * @return The plugin specific data.
-   */
-  private JsonObject getPluginData() {
-    JsonObject data = new JsonObject();
-
-    data.addProperty("pluginName", name); // Append the name of the server software
-    data.addProperty("id", pluginId);
-    data.addProperty("metricsRevision", B_STATS_METRICS_REVISION);
-    JsonArray customCharts = new JsonArray();
-    for (CustomChart customChart : charts) {
-      // Add the data of the custom charts
-      JsonObject chart = customChart.getRequestJsonObject();
-      if (chart == null) { // If the chart is null, we skip it
-        continue;
-      }
-      customCharts.add(chart);
-    }
-    data.add("customCharts", customCharts);
-
-    return data;
-  }
-
-  /**
-   * Gets the server specific data.
-   *
-   * @return The server specific data.
-   */
-  private JsonObject getServerData() {
-    // OS specific data
-    String osName = System.getProperty("os.name");
-    String osArch = System.getProperty("os.arch");
-    String osVersion = System.getProperty("os.version");
-    int coreCount = Runtime.getRuntime().availableProcessors();
-
-    JsonObject data = new JsonObject();
-
-    data.addProperty("serverUUID", serverUuid);
-
-    data.addProperty("osName", osName);
-    data.addProperty("osArch", osArch);
-    data.addProperty("osVersion", osVersion);
-    data.addProperty("coreCount", coreCount);
-
-    return data;
-  }
-
-  /**
-   * Collects the data and sends it afterwards.
-   */
-  private void submitData() {
-    final JsonObject data = getServerData();
-
-    JsonArray pluginData = new JsonArray();
-    pluginData.add(getPluginData());
-    data.add("plugins", pluginData);
-
-    try {
-      // We are still in the Thread of the timer, so nothing get blocked :)
-      sendData(data);
-    } catch (Exception e) {
-      // Something went wrong! :(
-      if (logFailedRequests) {
-        logger.warn("Could not submit stats of {}", name, e);
-      }
-    }
-  }
-
-  /**
-   * Sends the data to the bStats server.
-   *
-   * @param data The data to send.
-   * @throws Exception If the request failed.
-   */
-  private void sendData(JsonObject data) throws Exception {
-    if (data == null) {
-      throw new IllegalArgumentException("Data cannot be null!");
-    }
-
-    // Compress the data to save bandwidth
-    ListenableFuture<Response> future = server.getAsyncHttpClient()
-        .preparePost(URL)
-        .addHeader(HttpHeaderNames.CONTENT_ENCODING, "gzip")
-        .addHeader(HttpHeaderNames.ACCEPT, "application/json")
-        .addHeader(HttpHeaderNames.CONTENT_TYPE, "application/json")
-        .setBody(createResponseBody(data))
-        .execute();
-    future.addListener(() -> {
-      if (logFailedRequests) {
-        try {
-          Response r = future.get();
-          if (r.getStatusCode() != 429) {
-            logger.error("Got HTTP status code {} when sending metrics to bStats",
-                r.getStatusCode());
-          }
-        } catch (InterruptedException e) {
-          Thread.currentThread().interrupt();
-        } catch (ExecutionException e) {
-          logger.error("Unable to send metrics to bStats", e);
-        }
-      }
-    }, null);
-  }
-
-  private static byte[] createResponseBody(JsonObject object) throws IOException {
-    ByteArrayOutputStream os = new ByteArrayOutputStream();
-    try (Writer writer =
-        new BufferedWriter(
-            new OutputStreamWriter(
-                new GZIPOutputStream(os), StandardCharsets.UTF_8
-            )
-        )
-    ) {
-      VelocityServer.GENERAL_GSON.toJson(object, writer);
-    }
-    return os.toByteArray();
-  }
-
-  /**
-   * Represents a custom chart.
-   */
-  public abstract static class CustomChart {
-
-    // The id of the chart
-    final String chartId;
-
-    /**
-     * Class constructor.
-     *
-     * @param chartId The id of the chart.
-     */
-    CustomChart(String chartId) {
-      if (chartId == null || chartId.isEmpty()) {
-        throw new IllegalArgumentException("ChartId cannot be null or empty!");
-      }
-      this.chartId = chartId;
-    }
-
-    private JsonObject getRequestJsonObject() {
-      JsonObject chart = new JsonObject();
-      chart.addProperty("chartId", chartId);
-      try {
-        JsonObject data = getChartData();
-        if (data == null) {
-          // If the data is null we don't send the chart.
-          return null;
-        }
-        chart.add("data", data);
-      } catch (Throwable t) {
-        return null;
-      }
-      return chart;
-    }
-
-    protected abstract JsonObject getChartData() throws Exception;
-
-  }
-
-  /**
-   * Represents a custom simple pie.
-   */
-  public static class SimplePie extends CustomChart {
-
-    private final Callable<String> callable;
-
-    /**
-     * Class constructor.
-     *
-     * @param chartId  The id of the chart.
-     * @param callable The callable which is used to request the chart data.
-     */
-    public SimplePie(String chartId, Callable<String> callable) {
-      super(chartId);
-      this.callable = callable;
-    }
-
-    @Override
-    protected JsonObject getChartData() throws Exception {
-      JsonObject data = new JsonObject();
-      String value = callable.call();
-      if (value == null || value.isEmpty()) {
-        // Null = skip the chart
-        return null;
-      }
-      data.addProperty("value", value);
-      return data;
-    }
-  }
-
-  /**
-   * Represents a custom advanced pie.
-   */
-  public static class AdvancedPie extends CustomChart {
-
-    private final Callable<Map<String, Integer>> callable;
-
-    /**
-     * Class constructor.
-     *
-     * @param chartId  The id of the chart.
-     * @param callable The callable which is used to request the chart data.
-     */
-    public AdvancedPie(String chartId, Callable<Map<String, Integer>> callable) {
-      super(chartId);
-      this.callable = callable;
-    }
-
-    @Override
-    protected JsonObject getChartData() throws Exception {
-      Map<String, Integer> map = callable.call();
-      if (map == null || map.isEmpty()) {
-        // Null = skip the chart
-        return null;
-      }
-
-      JsonObject data = new JsonObject();
-      JsonObject values = new JsonObject();
-      boolean allSkipped = true;
-      for (Map.Entry<String, Integer> entry : map.entrySet()) {
-        if (entry.getValue() == 0) {
-          continue; // Skip this invalid
-        }
-        allSkipped = false;
-        values.addProperty(entry.getKey(), entry.getValue());
-      }
-      if (allSkipped) {
-        // Null = skip the chart
-        return null;
-      }
-      data.add("values", values);
-      return data;
-    }
-  }
-
-  /**
-   * Represents a custom drilldown pie.
-   */
-  public static class DrilldownPie extends CustomChart {
-
-    private final Callable<Map<String, Map<String, Integer>>> callable;
-
-    /**
-     * Class constructor.
-     *
-     * @param chartId  The id of the chart.
-     * @param callable The callable which is used to request the chart data.
-     */
-    public DrilldownPie(String chartId, Callable<Map<String, Map<String, Integer>>> callable) {
-      super(chartId);
-      this.callable = callable;
-    }
-
-    @Override
-    public JsonObject getChartData() throws Exception {
-      Map<String, Map<String, Integer>> map = callable.call();
-      if (map == null || map.isEmpty()) {
-        // Null = skip the chart
-        return null;
-      }
-      boolean reallyAllSkipped = true;
-      JsonObject data = new JsonObject();
-      JsonObject values = new JsonObject();
-      for (Map.Entry<String, Map<String, Integer>> entryValues : map.entrySet()) {
-        JsonObject value = new JsonObject();
-        boolean allSkipped = true;
-        for (Map.Entry<String, Integer> valueEntry : map.get(entryValues.getKey()).entrySet()) {
-          value.addProperty(valueEntry.getKey(), valueEntry.getValue());
-          allSkipped = false;
-        }
-        if (!allSkipped) {
-          reallyAllSkipped = false;
-          values.add(entryValues.getKey(), value);
-        }
-      }
-      if (reallyAllSkipped) {
-        // Null = skip the chart
-        return null;
-      }
-      data.add("values", values);
-      return data;
-    }
-  }
-
-  /**
-   * Represents a custom single line chart.
-   */
-  public static class SingleLineChart extends CustomChart {
-
-    private final Callable<Integer> callable;
-
-    /**
-     * Class constructor.
-     *
-     * @param chartId  The id of the chart.
-     * @param callable The callable which is used to request the chart data.
-     */
-    public SingleLineChart(String chartId, Callable<Integer> callable) {
-      super(chartId);
-      this.callable = callable;
-    }
-
-    @Override
-    protected JsonObject getChartData() throws Exception {
-      JsonObject data = new JsonObject();
-      int value = callable.call();
-      if (value == 0) {
-        // Null = skip the chart
-        return null;
-      }
-      data.addProperty("value", value);
-      return data;
-    }
-
-  }
-
-  /**
-   * Represents a custom multi line chart.
-   */
-  public static class MultiLineChart extends CustomChart {
-
-    private final Callable<Map<String, Integer>> callable;
-
-    /**
-     * Class constructor.
-     *
-     * @param chartId  The id of the chart.
-     * @param callable The callable which is used to request the chart data.
-     */
-    public MultiLineChart(String chartId, Callable<Map<String, Integer>> callable) {
-      super(chartId);
-      this.callable = callable;
-    }
-
-    @Override
-    protected JsonObject getChartData() throws Exception {
-      Map<String, Integer> map = callable.call();
-      if (map == null || map.isEmpty()) {
-        // Null = skip the chart
-        return null;
-      }
-      JsonObject data = new JsonObject();
-      JsonObject values = new JsonObject();
-      boolean allSkipped = true;
-      for (Map.Entry<String, Integer> entry : map.entrySet()) {
-        if (entry.getValue() == 0) {
-          continue; // Skip this invalid
-        }
-        allSkipped = false;
-        values.addProperty(entry.getKey(), entry.getValue());
-      }
-      if (allSkipped) {
-        // Null = skip the chart
-        return null;
-      }
-      data.add("values", values);
-      return data;
-    }
-
-  }
-
-  /**
-   * Represents a custom simple bar chart.
-   */
-  public static class SimpleBarChart extends CustomChart {
-
-    private final Callable<Map<String, Integer>> callable;
-
-    /**
-     * Class constructor.
-     *
-     * @param chartId  The id of the chart.
-     * @param callable The callable which is used to request the chart data.
-     */
-    public SimpleBarChart(String chartId, Callable<Map<String, Integer>> callable) {
-      super(chartId);
-      this.callable = callable;
-    }
-
-    @Override
-    protected JsonObject getChartData() throws Exception {
-      JsonObject data = new JsonObject();
-      JsonObject values = new JsonObject();
-      Map<String, Integer> map = callable.call();
-      if (map == null || map.isEmpty()) {
-        // Null = skip the chart
-        return null;
-      }
-      for (Map.Entry<String, Integer> entry : map.entrySet()) {
-        JsonArray categoryValues = new JsonArray();
-        categoryValues.add(entry.getValue());
-        values.add(entry.getKey(), categoryValues);
-      }
-      data.add("values", values);
-      return data;
-    }
-
-  }
-
-  /**
-   * Represents a custom advanced bar chart.
-   */
-  public static class AdvancedBarChart extends CustomChart {
-
-    private final Callable<Map<String, int[]>> callable;
-
-    /**
-     * Class constructor.
-     *
-     * @param chartId  The id of the chart.
-     * @param callable The callable which is used to request the chart data.
-     */
-    public AdvancedBarChart(String chartId, Callable<Map<String, int[]>> callable) {
-      super(chartId);
-      this.callable = callable;
-    }
-
-    @Override
-    protected JsonObject getChartData() throws Exception {
-      JsonObject values = new JsonObject();
-      Map<String, int[]> map = callable.call();
-      if (map == null || map.isEmpty()) {
-        // Null = skip the chart
-        return null;
-      }
-      boolean allSkipped = true;
-      for (Map.Entry<String, int[]> entry : map.entrySet()) {
-        if (entry.getValue().length == 0) {
-          continue; // Skip this invalid
-        }
-        allSkipped = false;
-        JsonArray categoryValues = new JsonArray();
-        for (int categoryValue : entry.getValue()) {
-          categoryValues.add(categoryValue);
-        }
-        values.add(entry.getKey(), categoryValues);
-      }
-      if (allSkipped) {
-        // Null = skip the chart
-        return null;
-      }
-      JsonObject data = new JsonObject();
-      data.add("values", values);
-      return data;
   }
 
+  private void appendPlatformData(JsonObjectBuilder builder) {
+    builder.appendField("osName", System.getProperty("os.name"));
+    builder.appendField("osArch", System.getProperty("os.arch"));
+    builder.appendField("osVersion", System.getProperty("os.version"));
+    builder.appendField("coreCount", Runtime.getRuntime().availableProcessors());
   }
 
   static class VelocityMetrics {
+
+    private static final Logger logger = LogManager.getLogger(Metrics.class);
+
     static void startMetrics(VelocityServer server, VelocityConfiguration.Metrics metricsConfig) {
-      if (!metricsConfig.isFromConfig()) {
+      Metrics metrics = new Metrics(logger, 4752, metricsConfig.isEnabled());
-        // Log an informational message.
-        logger.info("Velocity collects metrics and sends them to bStats (https://bstats.org).");
-        logger.info("bStats collects some basic information like how many people use Velocity and");
-        logger.info("their player count. This has no impact on performance and this data does not");
-        logger.info("identify your server in any way. However, you may opt-out by editing your");
-        logger.info("velocity.toml and setting enabled = false in the [metrics] section.");
-      }
-
-      // Load the data
-      String serverUuid = metricsConfig.getId();
-      boolean logFailedRequests = metricsConfig.isLogFailure();
-      // Only start Metrics, if it's enabled in the config
-      if (metricsConfig.isEnabled()) {
-        Metrics metrics = new Metrics("Velocity", 4752, serverUuid, logFailedRequests, server);
 
       metrics.addCustomChart(
-            new Metrics.SingleLineChart("players", server::getPlayerCount)
+          new SingleLineChart("players", server::getPlayerCount)
       );
       metrics.addCustomChart(
-            new Metrics.SingleLineChart("managed_servers", () -> server.getAllServers().size())
+          new SingleLineChart("managed_servers", () -> server.getAllServers().size())
       );
       metrics.addCustomChart(
-            new Metrics.SimplePie("online_mode",
+          new SimplePie("online_mode",
               () -> server.getConfiguration().isOnlineMode() ? "online" : "offline")
       );
-        metrics.addCustomChart(new Metrics.SimplePie("velocity_version",
+      metrics.addCustomChart(new SimplePie("velocity_version",
           () -> server.getVersion().getVersion()));
 
-        metrics.addCustomChart(new Metrics.DrilldownPie("java_version", () -> {
+      metrics.addCustomChart(new DrilldownPie("java_version", () -> {
         Map<String, Map<String, Integer>> map = new HashMap<>();
         String javaVersion = System.getProperty("java.version");
         Map<String, Integer> entry = new HashMap<>();
@@ -622,7 +133,6 @@ public class Metrics {
         return map;
       }));
     }
+  }
 
 }
-  }
-}

proxy/src/main/java/com/velocitypowered/proxy/Velocity.java

@@ -8,9 +8,12 @@ import org.apache.logging.log4j.Logger;
 
 public class Velocity {
 
-  private static final Logger logger = LogManager.getLogger(Velocity.class);
+  private static final Logger logger;
 
   static {
+    System.setProperty("java.util.logging.manager", "org.apache.logging.log4j.jul.LogManager");
+    logger = LogManager.getLogger(Velocity.class);
+
     // By default, Netty allocates 16MiB arenas for the PooledByteBufAllocator. This is too much
     // memory for Minecraft, which imposes a maximum packet size of 2MiB! We'll use 4MiB as a more
     // sane default.

proxy/src/main/java/com/velocitypowered/proxy/command/CommandNodeFactory.java

@@ -59,6 +59,9 @@ public interface CommandNodeFactory<T extends Command> {
           (context, builder) -> {
             I invocation = createInvocation(context);
 
+            if (!command.hasPermission(invocation)) {
+                return builder.buildFuture();
+            }
             return command.suggestAsync(invocation).thenApply(values -> {
               for (String value : values) {
                 builder.suggest(value);

proxy/src/main/java/com/velocitypowered/proxy/command/builtin/VelocityCommand.java

@@ -38,6 +38,7 @@ import net.kyori.adventure.text.TextComponent;
 import net.kyori.adventure.text.event.ClickEvent;
 import net.kyori.adventure.text.event.HoverEvent;
 import net.kyori.adventure.text.format.NamedTextColor;
+import net.kyori.adventure.text.format.TextColor;
 import net.kyori.adventure.text.format.TextDecoration;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
@@ -188,6 +189,7 @@ public class VelocityCommand implements SimpleCommand {
 
   private static class Info implements SubCommand {
 
+    private static final TextColor VELOCITY_COLOR = TextColor.fromHexString("#09add3");
     private final ProxyServer server;
 
     private Info(ProxyServer server) {
@@ -205,11 +207,11 @@ public class VelocityCommand implements SimpleCommand {
 
       TextComponent velocity = Component.text().content(version.getName() + " ")
           .decoration(TextDecoration.BOLD, true)
-          .color(NamedTextColor.DARK_AQUA)
+          .color(VELOCITY_COLOR)
           .append(Component.text(version.getVersion()).decoration(TextDecoration.BOLD, false))
           .build();
       TextComponent copyright = Component
-          .text("Copyright 2018-2020 " + version.getVendor() + ". " + version.getName()
+          .text("Copyright 2018-2021 " + version.getVendor() + ". " + version.getName()
               + " is freely licensed under the terms of the MIT License.");
       source.sendMessage(Identity.nil(), velocity);
       source.sendMessage(Identity.nil(), copyright);

proxy/src/main/java/com/velocitypowered/proxy/config/VelocityConfiguration.java

@@ -30,7 +30,6 @@ import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 import java.util.Random;
-import java.util.UUID;
 import net.kyori.adventure.text.Component;
 import net.kyori.adventure.text.serializer.gson.GsonComponentSerializer;
 import net.kyori.adventure.text.serializer.legacy.LegacyComponentSerializer;
@@ -426,11 +425,6 @@ public class VelocityConfiguration implements ProxyConfig {
     }
     forwardingSecret = forwardingSecretString.getBytes(StandardCharsets.UTF_8);
 
-    if (!config.contains("metrics.id") || config.<String>get("metrics.id").isEmpty()) {
-      config.set("metrics.id", UUID.randomUUID().toString());
-      mustResave = true;
-    }
-
     if (mustResave) {
       config.save();
     }
@@ -448,7 +442,7 @@ public class VelocityConfiguration implements ProxyConfig {
         PingPassthroughMode.DISABLED);
 
     String bind = config.getOrElse("bind", "0.0.0.0:25577");
-    String motd = config.getOrElse("motd", "&3A Velocity Server");
+    String motd = config.getOrElse("motd", "&#09add3A Velocity Server");
     int maxPlayers = config.getIntOrElse("show-max-players", 500);
     Boolean onlineMode = config.getOrElse("online-mode", true);
     Boolean announceForge = config.getOrElse("announce-forge", true);
@@ -636,7 +630,11 @@ public class VelocityConfiguration implements ProxyConfig {
         this.loginRatelimit = config.getIntOrElse("login-ratelimit", 3000);
         this.connectionTimeout = config.getIntOrElse("connection-timeout", 5000);
         this.readTimeout = config.getIntOrElse("read-timeout", 30000);
+        if (config.contains("haproxy-protocol")) {
+          this.proxyProtocol = config.getOrElse("haproxy-protocol", false);
+        } else {
           this.proxyProtocol = config.getOrElse("proxy-protocol", false);
+        }
         this.tcpFastOpen = config.getOrElse("tcp-fast-open", false);
         this.bungeePluginMessageChannel = config.getOrElse("bungee-plugin-message-channel", true);
         this.showPingRequests = config.getOrElse("show-ping-requests", false);
@@ -769,39 +767,16 @@ public class VelocityConfiguration implements ProxyConfig {
 
   public static class Metrics {
     private boolean enabled = true;
-    private String id = UUID.randomUUID().toString();
-    private boolean logFailure = false;
-
-    private boolean fromConfig;
-
-    private Metrics() {
-      this.fromConfig = false;
-    }
 
     private Metrics(CommentedConfig toml) {
       if (toml != null) {
-        this.enabled = toml.getOrElse("enabled", false);
+        this.enabled = toml.getOrElse("enabled", true);
-        this.id = toml.getOrElse("id", UUID.randomUUID().toString());
-        this.logFailure = toml.getOrElse("log-failure", false);
-        this.fromConfig = true;
       }
     }
 
     public boolean isEnabled() {
       return enabled;
     }
-
-    public String getId() {
-      return id;
-    }
-
-    public boolean isLogFailure() {
-      return logFailure;
-    }
-
-    public boolean isFromConfig() {
-      return fromConfig;
-    }
   }
 
   public static class Messages {

proxy/src/main/java/com/velocitypowered/proxy/connection/MinecraftConnection.java

@@ -196,6 +196,8 @@ public class MinecraftConnection extends ChannelInboundHandlerAdapter {
   public void write(Object msg) {
     if (channel.isActive()) {
       channel.writeAndFlush(msg, channel.voidPromise());
+    } else {
+      ReferenceCountUtil.release(msg);
     }
   }
 
@@ -206,6 +208,8 @@ public class MinecraftConnection extends ChannelInboundHandlerAdapter {
   public void delayedWrite(Object msg) {
     if (channel.isActive()) {
       channel.write(msg, channel.voidPromise());
+    } else {
+      ReferenceCountUtil.release(msg);
     }
   }
 
@@ -379,17 +383,26 @@ public class MinecraftConnection extends ChannelInboundHandlerAdapter {
     if (threshold == -1) {
       channel.pipeline().remove(COMPRESSION_DECODER);
       channel.pipeline().remove(COMPRESSION_ENCODER);
-      return;
+    } else {
-    }
+      MinecraftCompressDecoder decoder = (MinecraftCompressDecoder) channel.pipeline()
-
+          .get(COMPRESSION_DECODER);
+      MinecraftCompressEncoder encoder = (MinecraftCompressEncoder) channel.pipeline()
+          .get(COMPRESSION_ENCODER);
+      if (decoder != null && encoder != null) {
+        decoder.setThreshold(threshold);
+        encoder.setThreshold(threshold);
+      } else {
         int level = server.getConfiguration().getCompressionLevel();
         VelocityCompressor compressor = Natives.compress.get().create(level);
-    MinecraftCompressEncoder encoder = new MinecraftCompressEncoder(threshold, compressor);
+
-    MinecraftCompressDecoder decoder = new MinecraftCompressDecoder(threshold, compressor);
+        encoder = new MinecraftCompressEncoder(threshold, compressor);
+        decoder = new MinecraftCompressDecoder(threshold, compressor);
 
         channel.pipeline().addBefore(MINECRAFT_DECODER, COMPRESSION_DECODER, decoder);
         channel.pipeline().addBefore(MINECRAFT_ENCODER, COMPRESSION_ENCODER, encoder);
       }
+    }
+  }
 
   /**
    * Enables encryption on the connection.

proxy/src/main/java/com/velocitypowered/proxy/connection/backend/BackendPlaySessionHandler.java

@@ -30,6 +30,7 @@ import com.velocitypowered.proxy.network.packet.serverbound.ServerboundPluginMes
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.ByteBufUtil;
 import io.netty.buffer.Unpooled;
+import io.netty.channel.Channel;
 import io.netty.handler.timeout.ReadTimeoutException;
 import java.util.Collection;
 import org.apache.logging.log4j.LogManager;
@@ -38,6 +39,8 @@ import org.apache.logging.log4j.Logger;
 public class BackendPlaySessionHandler implements MinecraftSessionHandler {
 
   private static final Logger logger = LogManager.getLogger(BackendPlaySessionHandler.class);
+  private static final boolean BACKPRESSURE_LOG = Boolean
+      .getBoolean("velocity.log-server-backpressure");
   private final VelocityServer server;
   private final VelocityServerConnection serverConn;
   private final ClientPlaySessionHandler playerSessionHandler;
@@ -64,11 +67,14 @@ public class BackendPlaySessionHandler implements MinecraftSessionHandler {
   @Override
   public void activated() {
     serverConn.getServer().addPlayer(serverConn.getPlayer());
+
+    if (server.getConfiguration().isBungeePluginChannelEnabled()) {
       MinecraftConnection serverMc = serverConn.ensureConnected();
       serverMc.write(PluginMessageUtil.constructChannelsPacket(serverMc.getProtocolVersion(),
-        ImmutableList.of(getBungeeCordChannel(serverMc.getProtocolVersion())), ServerboundPluginMessagePacket.FACTORY
+          ImmutableList.of(getBungeeCordChannel(serverMc.getProtocolVersion()))
       ));
     }
+  }
 
   @Override
   public boolean beforeHandle() {
@@ -286,4 +292,20 @@ public class BackendPlaySessionHandler implements MinecraftSessionHandler {
       }
     }
   }
+
+  @Override
+  public void writabilityChanged() {
+    Channel serverChan = serverConn.ensureConnected().getChannel();
+    boolean writable = serverChan.isWritable();
+
+    if (BACKPRESSURE_LOG) {
+      if (writable) {
+        logger.info("{} is not writable, not auto-reading player connection data", this.serverConn);
+      } else {
+        logger.info("{} is writable, will auto-read player connection data", this.serverConn);
+      }
+    }
+
+    playerConnection.setAutoReading(writable);
+  }
 }

proxy/src/main/java/com/velocitypowered/proxy/connection/backend/BungeeCordMessageResponder.java

@@ -262,45 +262,34 @@ public class BungeeCordMessageResponder {
     });
   }
 
-  private ByteBuf prepareForwardMessage(ByteBufDataInput in) {
-    String channel = in.readUTF();
-    short messageLength = in.readShort();
-
-    ByteBuf buf = Unpooled.buffer();
-    ByteBufDataOutput forwarded = new ByteBufDataOutput(buf);
-    forwarded.writeUTF(channel);
-    forwarded.writeShort(messageLength);
-    buf.writeBytes(in.unwrap().readSlice(messageLength));
-    return buf;
-  }
-
   private void processForwardToPlayer(ByteBufDataInput in) {
-    proxy.getPlayer(in.readUTF())
+    Optional<Player> player = proxy.getPlayer(in.readUTF());
-        .flatMap(Player::getCurrentServer)
+    if (player.isPresent()) {
-        .ifPresent(server -> sendServerResponse(player, prepareForwardMessage(in)));
+      ByteBuf toForward = in.unwrap().copy();
+      sendServerResponse((ConnectedPlayer) player.get(), toForward);
+    }
   }
 
   private void processForwardToServer(ByteBufDataInput in) {
     String target = in.readUTF();
-    ByteBuf toForward = prepareForwardMessage(in);
+    ByteBuf toForward = in.unwrap().copy();
     if (target.equals("ALL")) {
-      ByteBuf unreleasableForward = Unpooled.unreleasableBuffer(toForward);
       try {
         for (RegisteredServer rs : proxy.getAllServers()) {
-          ((VelocityRegisteredServer) rs).sendPluginMessage(LEGACY_CHANNEL, unreleasableForward);
+          ((VelocityRegisteredServer) rs).sendPluginMessage(LEGACY_CHANNEL,
+              toForward.retainedSlice());
         }
       } finally {
         toForward.release();
       }
     } else {
-      proxy.getServer(target).ifPresent(rs -> ((VelocityRegisteredServer) rs)
+      Optional<RegisteredServer> server = proxy.getServer(target);
-          .sendPluginMessage(LEGACY_CHANNEL, toForward));
+      if (server.isPresent()) {
+        ((VelocityRegisteredServer) server.get()).sendPluginMessage(LEGACY_CHANNEL, toForward);
+      } else {
+        toForward.release();
       }
     }
-
-  // Note: this method will always release the buffer!
-  private void sendResponseOnConnection(ByteBuf buf) {
-    sendServerResponse(this.player, buf);
   }
 
   static String getBungeeCordChannel(ProtocolVersion version) {
@@ -308,29 +297,17 @@ public class BungeeCordMessageResponder {
         : LEGACY_CHANNEL.getId();
   }
 
+  // Note: this method will always release the buffer!
+  private void sendResponseOnConnection(ByteBuf buf) {
+    sendServerResponse(this.player, buf);
+  }
+
   // Note: this method will always release the buffer!
   private static void sendServerResponse(ConnectedPlayer player, ByteBuf buf) {
     MinecraftConnection serverConnection = player.ensureAndGetCurrentServer().ensureConnected();
     String chan = getBungeeCordChannel(serverConnection.getProtocolVersion());
-
+    ServerboundPluginMessagePacket msg = new ServerboundPluginMessagePacket(chan, buf);
-    ServerboundPluginMessagePacket msg = null;
+    serverConnection.write(msg);
-    boolean released = false;
-
-    try {
-      VelocityServerConnection vsc = player.getConnectedServer();
-      if (vsc == null) {
-        return;
-      }
-
-      MinecraftConnection serverConn = vsc.ensureConnected();
-      msg = new ServerboundPluginMessagePacket(chan, buf);
-      serverConn.write(msg);
-      released = true;
-    } finally {
-      if (!released && msg != null) {
-        msg.release();
-      }
-    }
   }
 
   boolean process(AbstractPluginMessagePacket<?> message) {

proxy/src/main/java/com/velocitypowered/proxy/connection/backend/VelocityServerConnection.java

@@ -32,7 +32,9 @@ import io.netty.channel.ChannelFutureListener;
 import java.net.InetSocketAddress;
 import java.net.SocketAddress;
 import java.nio.charset.StandardCharsets;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.concurrent.CompletableFuture;
 import java.util.function.UnaryOperator;
 import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
@@ -47,8 +49,7 @@ public class VelocityServerConnection implements MinecraftConnectionAssociation,
   private boolean hasCompletedJoin = false;
   private boolean gracefulDisconnect = false;
   private BackendConnectionPhase connectionPhase = BackendConnectionPhases.UNKNOWN;
-  private long lastPingId;
+  private final Map<Long, Long> pendingPings = new HashMap<>();
-  private long lastPingSent;
   private @MonotonicNonNull DimensionRegistry activeDimensionRegistry;
 
   /**
@@ -112,7 +113,7 @@ public class VelocityServerConnection implements MinecraftConnectionAssociation,
       return getHandshakeRemoteAddress();
     }
     StringBuilder data = new StringBuilder()
-        .append(getHandshakeRemoteAddress())
+        .append(registeredServer.getServerInfo().getAddress().getHostString())
         .append('\0')
         .append(((InetSocketAddress) proxyPlayer.getRemoteAddress()).getHostString())
         .append('\0')
@@ -259,21 +260,8 @@ public class VelocityServerConnection implements MinecraftConnectionAssociation,
     return gracefulDisconnect;
   }
 
-  public long getLastPingId() {
+  public Map<Long, Long> getPendingPings() {
-    return lastPingId;
+    return pendingPings;
-  }
-
-  public long getLastPingSent() {
-    return lastPingSent;
-  }
-
-  void setLastPingId(long lastPingId) {
-    this.lastPingId = lastPingId;
-    this.lastPingSent = System.currentTimeMillis();
-  }
-
-  public void resetLastPingId() {
-    this.lastPingId = -1;
   }
 
   /**

proxy/src/main/java/com/velocitypowered/proxy/connection/client/ClientPlaySessionHandler.java

@@ -5,13 +5,17 @@ import static com.velocitypowered.api.network.ProtocolVersion.MINECRAFT_1_16;
 import static com.velocitypowered.api.network.ProtocolVersion.MINECRAFT_1_8;
 import static com.velocitypowered.proxy.network.PluginMessageUtil.constructChannelsPacket;
 
+import com.google.common.collect.ImmutableList;
 import com.velocitypowered.api.event.command.CommandExecuteEvent.CommandResult;
 import com.velocitypowered.api.event.connection.PluginMessageEvent;
+import com.velocitypowered.api.event.player.PlayerChannelRegisterEvent;
 import com.velocitypowered.api.event.player.PlayerChatEvent;
 import com.velocitypowered.api.event.player.PlayerResourcePackStatusEvent;
 import com.velocitypowered.api.event.player.TabCompleteEvent;
 import com.velocitypowered.api.network.ProtocolVersion;
 import com.velocitypowered.api.proxy.messages.ChannelIdentifier;
+import com.velocitypowered.api.proxy.messages.LegacyChannelIdentifier;
+import com.velocitypowered.api.proxy.messages.MinecraftChannelIdentifier;
 import com.velocitypowered.proxy.VelocityServer;
 import com.velocitypowered.proxy.connection.ConnectionTypes;
 import com.velocitypowered.proxy.connection.MinecraftConnection;
@@ -102,12 +106,14 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
   @Override
   public boolean handle(ServerboundKeepAlivePacket packet) {
     VelocityServerConnection serverConnection = player.getConnectedServer();
-    if (serverConnection != null && packet.getRandomId() == serverConnection.getLastPingId()) {
+    if (serverConnection != null) {
+      Long sentTime = serverConnection.getPendingPings().remove(packet.getRandomId());
+      if (sentTime != null) {
         MinecraftConnection smc = serverConnection.getConnection();
         if (smc != null) {
-        player.setPing(System.currentTimeMillis() - serverConnection.getLastPingSent());
+          player.setPing(System.currentTimeMillis() - sentTime);
           smc.write(packet);
-        serverConnection.resetLastPingId();
+        }
       }
     }
     return true;
@@ -191,7 +197,18 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
         logger.warn("A plugin message was received while the backend server was not "
             + "ready. Channel: {}. Packet discarded.", packet.getChannel());
       } else if (PluginMessageUtil.isRegister(packet)) {
-        player.getKnownChannels().addAll(PluginMessageUtil.getChannels(packet));
+        List<String> channels = PluginMessageUtil.getChannels(packet);
+        player.getKnownChannels().addAll(channels);
+        List<ChannelIdentifier> channelIdentifiers = new ArrayList<>();
+        for (String channel : channels) {
+          try {
+            channelIdentifiers.add(MinecraftChannelIdentifier.from(channel));
+          } catch (IllegalArgumentException e) {
+            channelIdentifiers.add(new LegacyChannelIdentifier(channel));
+          }
+        }
+        server.getEventManager().fireAndForget(new PlayerChannelRegisterEvent(player,
+                ImmutableList.copyOf(channelIdentifiers)));
         backendConn.write(packet.retain());
       } else if (PluginMessageUtil.isUnregister(packet)) {
         player.getKnownChannels().removeAll(PluginMessageUtil.getChannels(packet));
@@ -303,7 +320,7 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
     boolean writable = player.getConnection().getChannel().isWritable();
 
     if (!writable) {
-      // We might have packets queued for the server, so flush them now to free up memory.
+      // We might have packets queued from the server, so flush them now to free up memory.
       player.getConnection().flush();
     }
 

proxy/src/main/java/com/velocitypowered/proxy/connection/client/ConnectedPlayer.java

@@ -59,6 +59,7 @@ import java.net.SocketAddress;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
+import java.util.Objects;
 import java.util.Optional;
 import java.util.UUID;
 import java.util.concurrent.CompletableFuture;
@@ -103,6 +104,8 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player {
   private @Nullable VelocityServerConnection connectionInFlight;
   private @Nullable PlayerSettings settings;
   private @Nullable ModInfo modInfo;
+  private Component playerListHeader = Component.empty();
+  private Component playerListFooter = Component.empty();
   private final VelocityTabList tabList;
   private final VelocityServer server;
   private ClientConnectionPhase connectionPhase;
@@ -113,11 +116,6 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player {
   ConnectedPlayer(VelocityServer server, GameProfile profile, MinecraftConnection connection,
       @Nullable InetSocketAddress virtualHost, boolean onlineMode) {
     this.server = server;
-    if (connection.getProtocolVersion().gte(ProtocolVersion.MINECRAFT_1_8)) {
-      this.tabList = new VelocityTabList(connection);
-    } else {
-      this.tabList = new VelocityTabListLegacy(connection);
-    }
     this.profile = profile;
     this.connection = connection;
     this.virtualHost = virtualHost;
@@ -125,6 +123,12 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player {
     this.connectionPhase = connection.getType().getInitialClientPhase();
     this.knownChannels = CappedSet.create(MAX_PLUGIN_CHANNELS);
     this.onlineMode = onlineMode;
+
+    if (connection.getProtocolVersion().compareTo(ProtocolVersion.MINECRAFT_1_8) >= 0) {
+      this.tabList = new VelocityTabList(this);
+    } else {
+      this.tabList = new VelocityTabListLegacy(this);
+    }
   }
 
   @Override
@@ -264,8 +268,38 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player {
     }
   }
 
+  @Override
+  public Component getPlayerListHeader() {
+    return this.playerListHeader;
+  }
+
+  @Override
+  public Component getPlayerListFooter() {
+    return this.playerListFooter;
+  }
+
+  @Override
+  public void sendPlayerListHeader(@NonNull final Component header) {
+    this.sendPlayerListHeaderAndFooter(header, this.playerListFooter);
+  }
+
+  @Override
+  public void sendPlayerListFooter(@NonNull final Component footer) {
+    this.sendPlayerListHeaderAndFooter(this.playerListHeader, footer);
+  }
+
+  @Override
+  public void sendPlayerListHeaderAndFooter(final Component header, final Component footer) {
+    this.playerListHeader = Objects.requireNonNull(header, "header");
+    this.playerListFooter = Objects.requireNonNull(footer, "footer");
+    if (this.getProtocolVersion().compareTo(ProtocolVersion.MINECRAFT_1_8) >= 0) {
+      this.connection.write(HeaderAndFooter.create(header, footer, this.getProtocolVersion()));
+    }
+  }
+
   @Override
   public void showTitle(net.kyori.adventure.title.@NonNull Title title) {
+    if (this.getProtocolVersion().compareTo(ProtocolVersion.MINECRAFT_1_8) >= 0) {
       GsonComponentSerializer serializer = ProtocolUtils.getJsonChatSerializer(this
           .getProtocolVersion());
 
@@ -286,26 +320,35 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player {
 
       connection.flush();
     }
+  }
 
   @Override
   public void clearTitle() {
+    if (this.getProtocolVersion().compareTo(ProtocolVersion.MINECRAFT_1_8) >= 0) {
       connection.write(ClientboundTitlePacket.hide(this.getProtocolVersion()));
     }
+  }
 
   @Override
   public void resetTitle() {
+    if (this.getProtocolVersion().compareTo(ProtocolVersion.MINECRAFT_1_8) >= 0) {
       connection.write(ClientboundTitlePacket.reset(this.getProtocolVersion()));
     }
+  }
 
   @Override
   public void hideBossBar(@NonNull BossBar bar) {
+    if (this.getProtocolVersion().compareTo(ProtocolVersion.MINECRAFT_1_9) >= 0) {
       this.server.getBossBarManager().removeBossBar(this, bar);
     }
+  }
 
   @Override
   public void showBossBar(@NonNull BossBar bar) {
+    if (this.getProtocolVersion().compareTo(ProtocolVersion.MINECRAFT_1_9) >= 0) {
       this.server.getBossBarManager().addBossBar(this, bar);
     }
+  }
 
   @Override
   public ConnectionRequestBuilder createConnectionRequest(RegisteredServer server) {
@@ -317,6 +360,11 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player {
     this.profile = profile.withProperties(properties);
   }
 
+  @Override
+  public void clearHeaderAndFooter() {
+    tabList.clearHeaderAndFooter();
+  }
+
   @Override
   public VelocityTabList getTabList() {
     return tabList;
@@ -412,7 +460,8 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player {
       logger.error("{}: kicked from server {}: {}", this, server.getServerInfo().getName(),
           plainTextReason);
       handleConnectionException(server, disconnectReason, Component.text()
-          .append(messages.getKickPrefix(server.getServerInfo().getName()))
+          .append(messages.getKickPrefix(server.getServerInfo().getName())
+              .colorIfAbsent(NamedTextColor.RED))
           .color(NamedTextColor.RED)
           .append(disconnectReason)
           .build(), safe);
@@ -420,8 +469,8 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player {
       logger.error("{}: disconnected while connecting to {}: {}", this,
           server.getServerInfo().getName(), plainTextReason);
       handleConnectionException(server, disconnectReason, Component.text()
-          .append(messages.getDisconnectPrefix(server.getServerInfo().getName()))
+          .append(messages.getDisconnectPrefix(server.getServerInfo().getName())
-          .color(NamedTextColor.RED)
+              .colorIfAbsent(NamedTextColor.RED))
           .append(disconnectReason)
           .build(), safe);
     }
@@ -678,8 +727,10 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player {
   public void sendResourcePack(String url) {
     Preconditions.checkNotNull(url, "url");
 
+    if (this.getProtocolVersion().compareTo(ProtocolVersion.MINECRAFT_1_8) >= 0) {
       connection.write(new ClientboundResourcePackRequestPacket(url, ""));
     }
+  }
 
   @Override
   public void sendResourcePack(String url, byte[] hash) {
@@ -687,8 +738,10 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player {
     Preconditions.checkNotNull(hash, "hash");
     Preconditions.checkArgument(hash.length == 20, "Hash length is not 20");
 
+    if (this.getProtocolVersion().compareTo(ProtocolVersion.MINECRAFT_1_8) >= 0) {
       connection.write(new ClientboundResourcePackRequestPacket(url, ByteBufUtil.hexDump(hash)));
     }
+  }
 
   /**
    * Sends a {@link ClientboundKeepAlivePacket} packet to the player with a random ID.

proxy/src/main/java/com/velocitypowered/proxy/connection/client/LoginSessionHandler.java

@@ -36,6 +36,7 @@ import io.netty.buffer.ByteBuf;
 import java.net.InetSocketAddress;
 import java.security.GeneralSecurityException;
 import java.security.KeyPair;
+import java.security.MessageDigest;
 import java.util.Arrays;
 import java.util.Optional;
 import java.util.UUID;
@@ -90,7 +91,7 @@ public class LoginSessionHandler implements MinecraftSessionHandler {
     try {
       KeyPair serverKeyPair = server.getServerKeyPair();
       byte[] decryptedVerifyToken = decryptRsa(serverKeyPair, packet.getVerifyToken());
-      if (!Arrays.equals(verify, decryptedVerifyToken)) {
+      if (!MessageDigest.isEqual(verify, decryptedVerifyToken)) {
         throw new IllegalStateException("Unable to successfully decrypt the verification token.");
       }
 

proxy/src/main/java/com/velocitypowered/proxy/network/ProtocolUtils.java

@@ -16,6 +16,8 @@ import io.netty.handler.codec.CorruptedFrameException;
 import io.netty.handler.codec.DecoderException;
 import io.netty.handler.codec.EncoderException;
 
+import java.io.DataInput;
+import java.io.DataOutput;
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
@@ -227,11 +229,12 @@ public enum ProtocolUtils {
   /**
    * Reads a {@link net.kyori.adventure.nbt.CompoundBinaryTag} from the {@code buf}.
    * @param buf the buffer to read from
+   * @param reader the NBT reader to use
    * @return {@link net.kyori.adventure.nbt.CompoundBinaryTag} the CompoundTag from the buffer
    */
-  public static CompoundBinaryTag readCompoundTag(ByteBuf buf) {
+  public static CompoundBinaryTag readCompoundTag(ByteBuf buf, BinaryTagIO.Reader reader) {
     try {
-      return BinaryTagIO.readDataInput(new ByteBufInputStream(buf));
+      return reader.read((DataInput) new ByteBufInputStream(buf));
     } catch (IOException thrown) {
       throw new DecoderException(
               "Unable to parse NBT CompoundTag, full error: " + thrown.getMessage());
@@ -245,7 +248,7 @@ public enum ProtocolUtils {
    */
   public static void writeCompoundTag(ByteBuf buf, CompoundBinaryTag compoundTag) {
     try {
-      BinaryTagIO.writeDataOutput(compoundTag, new ByteBufOutputStream(buf));
+      BinaryTagIO.writer().write(compoundTag, (DataOutput) new ByteBufOutputStream(buf));
     } catch (IOException e) {
       throw new EncoderException("Unable to encode NBT CompoundTag");
     }

proxy/src/main/java/com/velocitypowered/proxy/network/packet/clientbound/ClientboundAvailableCommandsPacket.java

@@ -25,6 +25,7 @@ import com.velocitypowered.proxy.network.packet.PacketHandler;
 import com.velocitypowered.proxy.network.packet.PacketReader;
 import com.velocitypowered.proxy.network.serialization.brigadier.ArgumentPropertyRegistry;
 import io.netty.buffer.ByteBuf;
+import it.unimi.dsi.fastutil.objects.Object2IntLinkedOpenCustomHashMap;
 import it.unimi.dsi.fastutil.objects.Object2IntLinkedOpenHashMap;
 import it.unimi.dsi.fastutil.objects.Object2IntMap;
 import java.util.ArrayDeque;
@@ -99,7 +100,8 @@ public class ClientboundAvailableCommandsPacket implements Packet {
   public void encode(ByteBuf buf, PacketDirection direction, ProtocolVersion protocolVersion) {
     // Assign all the children an index.
     Deque<CommandNode<CommandSource>> childrenQueue = new ArrayDeque<>(ImmutableList.of(rootNode));
-    Object2IntMap<CommandNode<CommandSource>> idMappings = new Object2IntLinkedOpenHashMap<>();
+    Object2IntMap<CommandNode<CommandSource>> idMappings = new Object2IntLinkedOpenCustomHashMap<>(
+        IdentityHashStrategy.instance());
     while (!childrenQueue.isEmpty()) {
       CommandNode<CommandSource> child = childrenQueue.poll();
       if (!idMappings.containsKey(child)) {
@@ -207,6 +209,7 @@ public class ClientboundAvailableCommandsPacket implements Packet {
     private final int redirectTo;
     private final @Nullable ArgumentBuilder<CommandSource, ?> args;
     private @MonotonicNonNull CommandNode<CommandSource> built;
+    private boolean validated;
 
     private WireNode(int idx, byte flags, int[] children, int redirectTo,
         @Nullable ArgumentBuilder<CommandSource, ?> args) {
@@ -215,18 +218,34 @@ public class ClientboundAvailableCommandsPacket implements Packet {
       this.children = children;
       this.redirectTo = redirectTo;
       this.args = args;
+      this.validated = false;
     }
 
-    boolean toNode(WireNode[] wireNodes) {
+    void validate(WireNode[] wireNodes) {
-      if (this.built == null) {
       // Ensure all children exist. Note that we delay checking if the node has been built yet;
       // that needs to come after this node is built.
       for (int child : children) {
-          if (child >= wireNodes.length) {
+        if (child < 0 || child >= wireNodes.length) {
-            throw new IllegalStateException("Node points to non-existent index " + redirectTo);
+          throw new IllegalStateException("Node points to non-existent index " + child);
         }
       }
 
+      if (redirectTo != -1) {
+        if (redirectTo < 0 || redirectTo >= wireNodes.length) {
+          throw new IllegalStateException("Redirect node points to non-existent index "
+              + redirectTo);
+        }
+      }
+
+      this.validated = true;
+    }
+
+    boolean toNode(WireNode[] wireNodes) {
+      if (!this.validated) {
+        this.validate(wireNodes);
+      }
+
+      if (this.built == null) {
         int type = flags & FLAG_NODE_TYPE;
         if (type == NODE_TYPE_ROOT) {
           this.built = new RootCommandNode<>();
@@ -237,10 +256,6 @@ public class ClientboundAvailableCommandsPacket implements Packet {
 
           // Add any redirects
           if (redirectTo != -1) {
-            if (redirectTo >= wireNodes.length) {
-              throw new IllegalStateException("Node points to non-existent index " + redirectTo);
-            }
-
             WireNode redirect = wireNodes[redirectTo];
             if (redirect.built != null) {
               args.redirect(redirect.built);

proxy/src/main/java/com/velocitypowered/proxy/network/packet/clientbound/ClientboundJoinGamePacket.java

@@ -12,6 +12,7 @@ import com.velocitypowered.proxy.network.packet.PacketDirection;
 import com.velocitypowered.proxy.network.packet.PacketHandler;
 import com.velocitypowered.proxy.network.packet.PacketReader;
 import io.netty.buffer.ByteBuf;
+import net.kyori.adventure.nbt.BinaryTagIO;
 import net.kyori.adventure.nbt.BinaryTagTypes;
 import net.kyori.adventure.nbt.CompoundBinaryTag;
 import net.kyori.adventure.nbt.ListBinaryTag;
@@ -20,6 +21,7 @@ import org.checkerframework.checker.nullness.qual.Nullable;
 public class ClientboundJoinGamePacket implements Packet {
   public static final PacketReader<ClientboundJoinGamePacket> DECODER = PacketReader.method(ClientboundJoinGamePacket::new);
 
+  private static final BinaryTagIO.Reader JOINGAME_READER = BinaryTagIO.reader(2 * 1024 * 1024);
   private int entityId;
   private short gamemode;
   private int dimension;
@@ -37,14 +39,136 @@ public class ClientboundJoinGamePacket implements Packet {
   private short previousGamemode; // 1.16+
   private CompoundBinaryTag biomeRegistry; // 1.16.2+
 
-  public void withDimension(int dimension) {
+  public int getEntityId() {
-    this.dimension = dimension;
+    return entityId;
+  }
+
+  public void setEntityId(int entityId) {
+    this.entityId = entityId;
+  }
+
+  public short getGamemode() {
+    return gamemode;
+  }
+
+  public void setGamemode(short gamemode) {
+    this.gamemode = gamemode;
+  }
+
+  public int getDimension() {
+    return dimension;
   }
 
   public void setDimension(int dimension) {
     this.dimension = dimension;
   }
 
+  public long getPartialHashedSeed() {
+    return partialHashedSeed;
+  }
+
+  public short getDifficulty() {
+    return difficulty;
+  }
+
+  public void setDifficulty(short difficulty) {
+    this.difficulty = difficulty;
+  }
+
+  public int getMaxPlayers() {
+    return maxPlayers;
+  }
+
+  public void setMaxPlayers(int maxPlayers) {
+    this.maxPlayers = maxPlayers;
+  }
+
+  public @Nullable String getLevelType() {
+    return levelType;
+  }
+
+  public void setLevelType(String levelType) {
+    this.levelType = levelType;
+  }
+
+  public int getViewDistance() {
+    return viewDistance;
+  }
+
+  public void setViewDistance(int viewDistance) {
+    this.viewDistance = viewDistance;
+  }
+
+  public boolean isReducedDebugInfo() {
+    return reducedDebugInfo;
+  }
+
+  public void setReducedDebugInfo(boolean reducedDebugInfo) {
+    this.reducedDebugInfo = reducedDebugInfo;
+  }
+
+  public DimensionInfo getDimensionInfo() {
+    return dimensionInfo;
+  }
+
+  public void setDimensionInfo(DimensionInfo dimensionInfo) {
+    this.dimensionInfo = dimensionInfo;
+  }
+
+  public DimensionRegistry getDimensionRegistry() {
+    return dimensionRegistry;
+  }
+
+  public void setDimensionRegistry(DimensionRegistry dimensionRegistry) {
+    this.dimensionRegistry = dimensionRegistry;
+  }
+
+  public short getPreviousGamemode() {
+    return previousGamemode;
+  }
+
+  public void setPreviousGamemode(short previousGamemode) {
+    this.previousGamemode = previousGamemode;
+  }
+
+  public boolean getIsHardcore() {
+    return isHardcore;
+  }
+
+  public void setIsHardcore(boolean isHardcore) {
+    this.isHardcore = isHardcore;
+  }
+
+  public CompoundBinaryTag getBiomeRegistry() {
+    return biomeRegistry;
+  }
+
+  public void setBiomeRegistry(CompoundBinaryTag biomeRegistry) {
+    this.biomeRegistry = biomeRegistry;
+  }
+
+  public DimensionData getCurrentDimensionData() {
+    return currentDimensionData;
+  }
+
+  @Override
+  public String toString() {
+    return "JoinGame{"
+        + "entityId=" + entityId
+        + ", gamemode=" + gamemode
+        + ", dimension=" + dimension
+        + ", partialHashedSeed=" + partialHashedSeed
+        + ", difficulty=" + difficulty
+        + ", maxPlayers=" + maxPlayers
+        + ", levelType='" + levelType + '\''
+        + ", viewDistance=" + viewDistance
+        + ", reducedDebugInfo=" + reducedDebugInfo
+        + ", dimensionRegistry='" + dimensionRegistry + '\''
+        + ", dimensionInfo='" + dimensionInfo + '\''
+        + ", previousGamemode=" + previousGamemode
+        + '}';
+  }
+
   @Override
   public void decode(ByteBuf buf, PacketDirection direction, ProtocolVersion version) {
     this.entityId = buf.readInt();
@@ -61,7 +185,7 @@ public class ClientboundJoinGamePacket implements Packet {
     if (version.gte(ProtocolVersion.MINECRAFT_1_16)) {
       this.previousGamemode = buf.readByte();
       ImmutableSet<String> levelNames = ImmutableSet.copyOf(ProtocolUtils.readStringArray(buf));
-      CompoundBinaryTag registryContainer = ProtocolUtils.readCompoundTag(buf);
+      CompoundBinaryTag registryContainer = ProtocolUtils.readCompoundTag(buf, JOINGAME_READER);
       ListBinaryTag dimensionRegistryContainer = null;
       if (version.gte(ProtocolVersion.MINECRAFT_1_16_2)) {
         dimensionRegistryContainer = registryContainer.getCompound("minecraft:dimension_type")
@@ -74,8 +198,8 @@ public class ClientboundJoinGamePacket implements Packet {
       ImmutableSet<DimensionData> readData =
           DimensionRegistry.fromGameData(dimensionRegistryContainer, version);
       this.dimensionRegistry = new DimensionRegistry(readData, levelNames);
-      if (version.gte(ProtocolVersion.MINECRAFT_1_16_2)) {
+      if (version.compareTo(ProtocolVersion.MINECRAFT_1_16_2) >= 0) {
-        CompoundBinaryTag currentDimDataTag = ProtocolUtils.readCompoundTag(buf);
+        CompoundBinaryTag currentDimDataTag = ProtocolUtils.readCompoundTag(buf, JOINGAME_READER);
         dimensionIdentifier = ProtocolUtils.readString(buf);
         this.currentDimensionData = DimensionData.decodeBaseCompoundTag(currentDimDataTag, version)
             .annotateWith(dimensionIdentifier, null);
@@ -186,66 +310,6 @@ public class ClientboundJoinGamePacket implements Packet {
     }
   }
 
-  public int getEntityId() {
-    return entityId;
-  }
-
-  public short getGamemode() {
-    return gamemode;
-  }
-
-  public int getDimension() {
-    return dimension;
-  }
-
-  public long getPartialHashedSeed() {
-    return partialHashedSeed;
-  }
-
-  public short getDifficulty() {
-    return difficulty;
-  }
-
-  public int getMaxPlayers() {
-    return maxPlayers;
-  }
-
-  public @Nullable String getLevelType() {
-    return levelType;
-  }
-
-  public int getViewDistance() {
-    return viewDistance;
-  }
-
-  public boolean isReducedDebugInfo() {
-    return reducedDebugInfo;
-  }
-
-  public DimensionInfo getDimensionInfo() {
-    return dimensionInfo;
-  }
-
-  public DimensionRegistry getDimensionRegistry() {
-    return dimensionRegistry;
-  }
-
-  public short getPreviousGamemode() {
-    return previousGamemode;
-  }
-
-  public boolean getIsHardcore() {
-    return isHardcore;
-  }
-
-  public CompoundBinaryTag getBiomeRegistry() {
-    return biomeRegistry;
-  }
-
-  public DimensionData getCurrentDimensionData() {
-    return currentDimensionData;
-  }
-
   @Override
   public boolean handle(PacketHandler handler) {
     return handler.handle(this);

proxy/src/main/java/com/velocitypowered/proxy/network/packet/clientbound/ClientboundRespawnPacket.java

@@ -10,6 +10,7 @@ import com.velocitypowered.proxy.network.packet.PacketDirection;
 import com.velocitypowered.proxy.network.packet.PacketHandler;
 import com.velocitypowered.proxy.network.packet.PacketReader;
 import io.netty.buffer.ByteBuf;
+import net.kyori.adventure.nbt.BinaryTagIO;
 import net.kyori.adventure.nbt.CompoundBinaryTag;
 
 public class ClientboundRespawnPacket implements Packet {
@@ -102,9 +103,9 @@ public class ClientboundRespawnPacket implements Packet {
   public void decode(ByteBuf buf, PacketDirection direction, ProtocolVersion version) {
     String dimensionIdentifier = null;
     String levelName = null;
-    if (version.gte(ProtocolVersion.MINECRAFT_1_16)) {
+    if (version.compareTo(ProtocolVersion.MINECRAFT_1_16) >= 0) {
-      if (version.gte(ProtocolVersion.MINECRAFT_1_16_2)) {
+      if (version.compareTo(ProtocolVersion.MINECRAFT_1_16_2) >= 0) {
-        CompoundBinaryTag dimDataTag = ProtocolUtils.readCompoundTag(buf);
+        CompoundBinaryTag dimDataTag = ProtocolUtils.readCompoundTag(buf, BinaryTagIO.reader());
         dimensionIdentifier = ProtocolUtils.readString(buf);
         this.currentDimensionData = DimensionData.decodeBaseCompoundTag(dimDataTag, version)
             .annotateWith(dimensionIdentifier, null);

proxy/src/main/java/com/velocitypowered/proxy/network/pipeline/MinecraftCompressDecoder.java

@@ -20,7 +20,7 @@ public class MinecraftCompressDecoder extends MessageToMessageDecoder<ByteBuf> {
       Boolean.getBoolean("velocity.increased-compression-cap")
           ? HARD_MAXIMUM_UNCOMPRESSED_SIZE : VANILLA_MAXIMUM_UNCOMPRESSED_SIZE;
 
-  private final int threshold;
+  private int threshold;
   private final VelocityCompressor compressor;
 
   public MinecraftCompressDecoder(int threshold, VelocityCompressor compressor) {
@@ -60,4 +60,8 @@ public class MinecraftCompressDecoder extends MessageToMessageDecoder<ByteBuf> {
   public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
     compressor.close();
   }
+
+  public void setThreshold(int threshold) {
+    this.threshold = threshold;
+  }
 }

proxy/src/main/java/com/velocitypowered/proxy/network/pipeline/MinecraftCompressEncoder.java

@@ -9,7 +9,7 @@ import io.netty.handler.codec.MessageToByteEncoder;
 
 public class MinecraftCompressEncoder extends MessageToByteEncoder<ByteBuf> {
 
-  private final int threshold;
+  private int threshold;
   private final VelocityCompressor compressor;
 
   public MinecraftCompressEncoder(int threshold, VelocityCompressor compressor) {
@@ -20,7 +20,7 @@ public class MinecraftCompressEncoder extends MessageToByteEncoder<ByteBuf> {
   @Override
   protected void encode(ChannelHandlerContext ctx, ByteBuf msg, ByteBuf out) throws Exception {
     int uncompressed = msg.readableBytes();
-    if (uncompressed <= threshold) {
+    if (uncompressed < threshold) {
       // Under the threshold, there is nothing to do.
       ProtocolUtils.writeVarInt(out, 0);
       out.writeBytes(msg);
@@ -54,4 +54,8 @@ public class MinecraftCompressEncoder extends MessageToByteEncoder<ByteBuf> {
   public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
     compressor.close();
   }
+
+  public void setThreshold(int threshold) {
+    this.threshold = threshold;
+  }
 }

proxy/src/main/java/com/velocitypowered/proxy/network/pipeline/MinecraftDecoder.java

@@ -15,8 +15,8 @@ import io.netty.handler.codec.CorruptedFrameException;
 public class MinecraftDecoder extends ChannelInboundHandlerAdapter {
 
   public static final boolean DEBUG = Boolean.getBoolean("velocity.packet-decode-logging");
-  private static final QuietDecoderException DECODE_FAILED =
+  private static final QuietRuntimeException DECODE_FAILED =
-      new QuietDecoderException("A packet did not decode successfully (invalid data). If you are a "
+      new QuietRuntimeException("A packet did not decode successfully (invalid data). If you are a "
           + "developer, launch Velocity with -Dvelocity.packet-decode-logging=true to see more.");
 
   private final PacketDirection direction;
@@ -64,8 +64,16 @@ public class MinecraftDecoder extends ChannelInboundHandlerAdapter {
       ctx.fireChannelRead(buf);
     } else {
       try {
+        doLengthSanityChecks(buf, packet);
+
+        try {
+          packet.decode(buf, direction, registry.version);
+        } catch (Exception e) {
+          throw handleDecodeFailure(e, packet, packetId);
+        }
+
         if (buf.isReadable()) {
-          throw handleNotReadEnough(packet, packetId);
+          throw handleOverflow(packet, buf.readerIndex(), buf.writerIndex());
         }
         ctx.fireChannelRead(packet);
       } finally {
@@ -74,10 +82,30 @@ public class MinecraftDecoder extends ChannelInboundHandlerAdapter {
     }
   }
 
-  private Exception handleNotReadEnough(Packet packet, int packetId) {
+  private void doLengthSanityChecks(ByteBuf buf, Packet packet) throws Exception {
+    int expectedMinLen = packet.expectedMinLength(buf, direction, registry.version);
+    int expectedMaxLen = packet.expectedMaxLength(buf, direction, registry.version);
+    if (expectedMaxLen != -1 && buf.readableBytes() > expectedMaxLen) {
+      throw handleOverflow(packet, expectedMaxLen, buf.readableBytes());
+    }
+    if (buf.readableBytes() < expectedMinLen) {
+      throw handleUnderflow(packet, expectedMaxLen, buf.readableBytes());
+    }
+  }
+
+  private Exception handleOverflow(Packet packet, int expected, int actual) {
     if (DEBUG) {
-      return new CorruptedFrameException("Did not read full packet for " + packet.getClass() + " "
+      return new CorruptedFrameException("Packet sent for " + packet.getClass() + " was too "
-          + getExtraConnectionDetail(packetId));
+          + "big (expected " + expected + " bytes, got " + actual + " bytes)");
+    } else {
+      return DECODE_FAILED;
+    }
+  }
+
+  private Exception handleUnderflow(Packet packet, int expected, int actual) {
+    if (DEBUG) {
+      return new CorruptedFrameException("Packet sent for " + packet.getClass() + " was too "
+          + "small (expected " + expected + " bytes, got " + actual + " bytes)");
     } else {
       return DECODE_FAILED;
     }

proxy/src/main/java/com/velocitypowered/proxy/protocol/MinecraftPacket.java

@@ -0,0 +1,24 @@
+package com.velocitypowered.proxy.protocol;
+
+import com.velocitypowered.api.network.ProtocolVersion;
+import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
+import io.netty.buffer.ByteBuf;
+
+public interface MinecraftPacket {
+
+  void decode(ByteBuf buf, ProtocolUtils.Direction direction, ProtocolVersion protocolVersion);
+
+  void encode(ByteBuf buf, ProtocolUtils.Direction direction, ProtocolVersion protocolVersion);
+
+  boolean handle(MinecraftSessionHandler handler);
+
+  default int expectedMaxLength(ByteBuf buf, ProtocolUtils.Direction direction,
+      ProtocolVersion version) {
+    return -1;
+  }
+
+  default int expectedMinLength(ByteBuf buf, ProtocolUtils.Direction direction,
+      ProtocolVersion version) {
+    return 0;
+  }
+}

proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/PluginMessage.java

@@ -0,0 +1,129 @@
+package com.velocitypowered.proxy.protocol.packet;
+
+import static com.velocitypowered.proxy.protocol.util.PluginMessageUtil.transformLegacyToModernChannel;
+
+import com.velocitypowered.api.network.ProtocolVersion;
+import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
+import com.velocitypowered.proxy.protocol.MinecraftPacket;
+import com.velocitypowered.proxy.protocol.ProtocolUtils;
+import com.velocitypowered.proxy.protocol.util.DeferredByteBufHolder;
+import io.netty.buffer.ByteBuf;
+import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
+
+public class PluginMessage extends DeferredByteBufHolder implements MinecraftPacket {
+
+  private @Nullable String channel;
+
+  public PluginMessage() {
+    super(null);
+  }
+
+  public PluginMessage(String channel,
+      @MonotonicNonNull ByteBuf backing) {
+    super(backing);
+    this.channel = channel;
+  }
+
+  public String getChannel() {
+    if (channel == null) {
+      throw new IllegalStateException("Channel is not specified.");
+    }
+    return channel;
+  }
+
+  public void setChannel(String channel) {
+    this.channel = channel;
+  }
+
+  @Override
+  public String toString() {
+    return "PluginMessage{"
+        + "channel='" + channel + '\''
+        + ", data=" + super.toString()
+        + '}';
+  }
+
+  @Override
+  public void decode(ByteBuf buf, ProtocolUtils.Direction direction, ProtocolVersion version) {
+    this.channel = ProtocolUtils.readString(buf);
+    if (version.compareTo(ProtocolVersion.MINECRAFT_1_13) >= 0) {
+      this.channel = transformLegacyToModernChannel(this.channel);
+    }
+    if (version.compareTo(ProtocolVersion.MINECRAFT_1_8) >= 0) {
+      this.replace(buf.readRetainedSlice(buf.readableBytes()));
+    } else {
+      this.replace(ProtocolUtils.readRetainedByteBufSlice17(buf));
+    }
+
+  }
+
+  @Override
+  public void encode(ByteBuf buf, ProtocolUtils.Direction direction, ProtocolVersion version) {
+    if (channel == null) {
+      throw new IllegalStateException("Channel is not specified.");
+    }
+
+    if (refCnt() == 0) {
+      throw new IllegalStateException("Plugin message contents for " + this.channel
+          + " freed too many times.");
+    }
+
+    if (version.compareTo(ProtocolVersion.MINECRAFT_1_13) >= 0) {
+      ProtocolUtils.writeString(buf, transformLegacyToModernChannel(this.channel));
+    } else {
+      ProtocolUtils.writeString(buf, this.channel);
+    }
+    if (version.compareTo(ProtocolVersion.MINECRAFT_1_8) >= 0) {
+      buf.writeBytes(content());
+    } else {
+      ProtocolUtils.writeByteBuf17(content(), buf, true); // True for Forge support
+    }
+
+  }
+
+  @Override
+  public boolean handle(MinecraftSessionHandler handler) {
+    return handler.handle(this);
+  }
+
+  @Override
+  public PluginMessage copy() {
+    return (PluginMessage) super.copy();
+  }
+
+  @Override
+  public PluginMessage duplicate() {
+    return (PluginMessage) super.duplicate();
+  }
+
+  @Override
+  public PluginMessage retainedDuplicate() {
+    return (PluginMessage) super.retainedDuplicate();
+  }
+
+  @Override
+  public PluginMessage replace(ByteBuf content) {
+    return (PluginMessage) super.replace(content);
+  }
+
+  @Override
+  public PluginMessage retain() {
+    return (PluginMessage) super.retain();
+  }
+
+  @Override
+  public PluginMessage retain(int increment) {
+    return (PluginMessage) super.retain(increment);
+  }
+
+  @Override
+  public PluginMessage touch() {
+    return (PluginMessage) super.touch();
+  }
+
+  @Override
+  public PluginMessage touch(Object hint) {
+    return (PluginMessage) super.touch(hint);
+  }
+}

proxy/src/main/java/com/velocitypowered/proxy/scheduler/VelocityScheduler.java

@@ -7,6 +7,7 @@ import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Multimap;
 import com.google.common.collect.Multimaps;
 import com.google.common.util.concurrent.ThreadFactoryBuilder;
+import com.velocitypowered.api.plugin.PluginContainer;
 import com.velocitypowered.api.plugin.PluginManager;
 import com.velocitypowered.api.scheduler.ScheduledTask;
 import com.velocitypowered.api.scheduler.Scheduler;
@@ -183,8 +184,18 @@ public class VelocityScheduler implements Scheduler {
         currentTaskThread = Thread.currentThread();
         try {
           runnable.run();
-        } catch (Exception e) {
+        } catch (Throwable e) {
-          Log.logger.error("Exception in task {} by plugin {}", runnable, plugin, e);
+          //noinspection ConstantConditions
+          if (e instanceof InterruptedException) {
+            Thread.currentThread().interrupt();
+          } else {
+            String friendlyPluginName = pluginManager.fromInstance(plugin)
+                .map(container -> container.getDescription().getName()
+                      .orElse(container.getDescription().getId()))
+                .orElse("UNKNOWN");
+            Log.logger.error("Exception in task {} by plugin {}", runnable, friendlyPluginName,
+                e);
+          }
         } finally {
           if (repeat == 0) {
             onFinish();

proxy/src/main/java/com/velocitypowered/proxy/server/VelocityRegisteredServer.java

@@ -125,7 +125,9 @@ public class VelocityRegisteredServer implements RegisteredServer, ForwardingAud
   }
 
   /**
-   * Sends a plugin message to the server through this connection.
+   * Sends a plugin message to the server through this connection. The message will be released
+   * afterwards.
+   *
    * @param identifier the channel ID to use
    * @param data the data
    * @return whether or not the message was sent
@@ -133,11 +135,12 @@ public class VelocityRegisteredServer implements RegisteredServer, ForwardingAud
   public boolean sendPluginMessage(ChannelIdentifier identifier, ByteBuf data) {
     for (ConnectedPlayer player : players.values()) {
       VelocityServerConnection connection = player.getConnectedServer();
-      if (connection != null && connection.getServerInfo().equals(serverInfo)) {
+      if (connection != null && connection.getServer() == this) {
         return connection.sendPluginMessage(identifier, data);
       }
     }
 
+    data.release();
     return false;
   }
 

proxy/src/main/java/com/velocitypowered/proxy/tablist/VelocityTabList.java

@@ -21,16 +21,17 @@ import org.checkerframework.checker.nullness.qual.Nullable;
 
 public class VelocityTabList implements TabList {
 
+  protected final ConnectedPlayer player;
   protected final MinecraftConnection connection;
   protected final Map<UUID, VelocityTabListEntry> entries = new ConcurrentHashMap<>();
 
-  public VelocityTabList(MinecraftConnection connection) {
+  public VelocityTabList(final ConnectedPlayer player) {
-    this.connection = connection;
+    this.player = player;
+    this.connection = player.getConnection();
   }
 
   @Override
-  public void setHeaderAndFooter(net.kyori.adventure.text.Component header,
+  public void setHeaderAndFooter(Component header, Component footer) {
-      net.kyori.adventure.text.Component footer) {
     Preconditions.checkNotNull(header, "header");
     Preconditions.checkNotNull(footer, "footer");
     GsonComponentSerializer serializer = ProtocolUtils.getJsonChatSerializer(

proxy/src/main/java/com/velocitypowered/proxy/util/collect/IdentityHashStrategy.java

@@ -0,0 +1,24 @@
+package com.velocitypowered.proxy.util.collect;
+
+import it.unimi.dsi.fastutil.Hash.Strategy;
+
+public final class IdentityHashStrategy<T> implements Strategy<T> {
+
+  @SuppressWarnings("rawtypes")
+  private static final IdentityHashStrategy INSTANCE = new IdentityHashStrategy();
+
+  public static <T> Strategy<T> instance() {
+    //noinspection unchecked
+    return INSTANCE;
+  }
+
+  @Override
+  public int hashCode(T o) {
+    return System.identityHashCode(o);
+  }
+
+  @Override
+  public boolean equals(T a, T b) {
+    return a == b;
+  }
+}

proxy/src/main/resources/default-velocity.toml

@@ -6,7 +6,7 @@ bind = "0.0.0.0:25577"
 
 # What should be the MOTD? This gets displayed when the player adds your server to
 # their server list. Legacy color codes and JSON are accepted.
-motd = "&3A Velocity Server"
+motd = "&#09add3A Velocity Server"
 
 # What should we display for the maximum number of players? (Velocity does not support a cap
 # on the number of players online.)
@@ -33,7 +33,7 @@ prevent-client-proxy-connections = false
 #                  Velocity's native forwarding. Only applicable for Minecraft 1.13 or higher.
 player-info-forwarding-mode = "NONE"
 
-# If you are using modern or BungeeGuard IP forwarding, configure an unique secret here.
+# If you are using modern or BungeeGuard IP forwarding, configure a unique secret here.
 forwarding-secret = ""
 
 # Announce whether or not your server supports Forge. If you run a modded server, we
@@ -105,8 +105,9 @@ connection-timeout = 5000
 # Specify a read timeout for connections here. The default is 30 seconds.
 read-timeout = 30000
 
-# Enables compatibility with HAProxy.
+# Enables compatibility with HAProxy's PROXY protocol. If you don't know what this is for, then
-proxy-protocol = false
+# don't enable it.
+haproxy-protocol = false
 
 # Enables TCP fast open support on the proxy. Requires the proxy to run on Linux.
 tcp-fast-open = false
@@ -142,19 +143,6 @@ map = "Velocity"
 # Whether plugins should be shown in query response by default or not
 show-plugins = false
 
-[metrics]
-# Whether metrics will be reported to bStats (https://bstats.org).
-# bStats collects some basic information, like how many people use Velocity and their
-# player count. We recommend keeping bStats enabled, but if you're not comfortable with
-# this, you can turn this setting off. There is no performance penalty associated with
-# having metrics enabled, and data sent to bStats can't identify your server.
-enabled = true
-
-# A unique, anonymous ID to identify this proxy with.
-id = ""
-
-log-failure = false
-
 # Legacy color codes and JSON are accepted in all messages.
 [messages]
 # Prefix when the player gets kicked from a server.

proxy/src/test/java/com/velocitypowered/proxy/command/CommandManagerTests.java

@@ -24,6 +24,7 @@ import com.velocitypowered.api.command.SimpleCommand;
 import com.velocitypowered.proxy.event.MockEventManager;
 import com.velocitypowered.proxy.event.VelocityEventManager;
 import java.util.List;
+import java.util.concurrent.ExecutionException;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicReference;
 import org.junit.jupiter.api.Test;
@@ -423,6 +424,54 @@ public class CommandManagerTests {
             manager.offerSuggestions(MockCommandSource.INSTANCE, "foo2 baz ").join());
   }
 
+  @Test
+  void testSuggestionPermissions() throws ExecutionException, InterruptedException {
+    VelocityCommandManager manager = createManager();
+    RawCommand rawCommand = new RawCommand() {
+      @Override
+      public void execute(final Invocation invocation) {
+        fail("The Command should not be executed while testing suggestions");
+      }
+
+      @Override
+      public boolean hasPermission(Invocation invocation) {
+        return invocation.arguments().length() > 0;
+      }
+
+      @Override
+      public List<String> suggest(final Invocation invocation) {
+        return ImmutableList.of("suggestion");
+      }
+    };
+
+    manager.register(rawCommand, "foo");
+
+    assertTrue(manager.offerSuggestions(MockCommandSource.INSTANCE, "foo").get().isEmpty());
+    assertFalse(manager.offerSuggestions(MockCommandSource.INSTANCE, "foo bar").get().isEmpty());
+
+    Command oldCommand = new Command() {
+      @Override
+      public void execute(CommandSource source, String @NonNull [] args) {
+        fail("The Command should not be executed while testing suggestions");
+      }
+
+      @Override
+      public boolean hasPermission(CommandSource source, String @NonNull [] args) {
+        return args.length > 0;
+      }
+
+      @Override
+      public List<String> suggest(CommandSource source, String @NonNull [] currentArgs) {
+        return ImmutableList.of("suggestion");
+      }
+    };
+
+    manager.register(oldCommand, "bar");
+
+    assertTrue(manager.offerSuggestions(MockCommandSource.INSTANCE, "bar").get().isEmpty());
+    assertFalse(manager.offerSuggestions(MockCommandSource.INSTANCE, "bar foo").get().isEmpty());
+  }
+
   static class NoopSimpleCommand implements SimpleCommand {
     @Override
     public void execute(final Invocation invocation) {