Release 2.0.10 (#126 )

Remove lockdown mode (#125 )
* https://discord.com/channels/923308209769426994/1180500530896842832
2026-11-05 17:22:34 -05:00 · 2023-12-15 16:02:44 +01:00 · 2023-12-15 15:49:50 +01:00 · 2023-12-15 15:44:14 +01:00 · 2023-12-07 21:16:20 +01:00 · 2023-12-07 21:00:18 +01:00
43 changed files with 1507 additions and 488 deletions
@@ -9,6 +9,7 @@
  
  <!-- Badges & icons -->
  [![](https://github.com/jonesdevelopment/sonar/actions/workflows/gradle.yml/badge.svg)](https://github.com/jonesdevelopment/sonar/actions/workflows/gradle.yml)
+  [![](https://www.codefactor.io/repository/github/jonesdevelopment/sonar/badge/main)](https://www.codefactor.io/repository/github/jonesdevelopment/sonar/overview/main)
  [![](https://img.shields.io/github/v/release/jonesdevelopment/sonar)](https://github.com/jonesdevelopment/sonar/releases)
  [![](https://img.shields.io/github/issues/jonesdevelopment/sonar)](https://github.com/jonesdevelopment/sonar/issues)
  [![](https://img.shields.io/discord/923308209769426994.svg?logo=discord)](https://jonesdev.xyz/discord)
@@ -46,7 +46,7 @@ allprojects {
    implementation("com.j256.ormlite:ormlite-jdbc:6.1") // ORM
    implementation("xyz.jonesdev:cappuccino:0.1.6-SNAPSHOT") // expiring cache

-    compileOnly("io.netty:netty-all:4.1.100.Final") // netty
+    compileOnly("io.netty:netty-all:4.1.101.Final") // netty
  }
 }

@@ -71,16 +71,28 @@ tasks {
    // Set the file name of the shadowed jar
    archiveFileName.set("Sonar.jar")

+    // Remove file timestamps
+    isPreserveFileTimestamps = false
+
    // bStats has to be relocated to the Sonar package otherwise it throws an exception
    // https://github.com/Bastian/bstats-metrics/blob/master/base/src/main/java/org/bstats/MetricsBase.java#L251
    relocate("org.bstats", "xyz.jonesdev.sonar.libs.bstats")

    // https://github.com/jonesdevelopment/sonar/issues/46
    // Relocate some packages, so we don't run into issues where we accidentally use Velocity's classes
-    relocate("net.kyori.adventure.nbt", "xyz.jonesdev.sonar.libs.nbt")
    relocate("org.simpleyaml", "xyz.jonesdev.sonar.libs.yaml")
    relocate("com.google.gson", "xyz.jonesdev.sonar.libs.gson")
    relocate("com.j256.ormlite", "xyz.jonesdev.sonar.libs.ormlite")
+    relocate("xyz.jonesdev.cappuccino", "xyz.jonesdev.sonar.libs.cappuccino")
+    relocate("net.kyori.examination", "xyz.jonesdev.sonar.libs.examination")
+    // We have to be careful here, so we don't accidentally break adventure
+    relocate("net.kyori.adventure", "xyz.jonesdev.sonar.libs.adventure") {
+      exclude("net.kyori.adventure.text.**")
+      exclude("net.kyori.adventure.audience.**")
+    }
+
+    // Exclude unnecessary metadata information
+    exclude("META-INF/versions/**")
  }

  compileJava {
@@ -1,3 +1,3 @@
 group=xyz.jonesdev.sonar
-version=2.0.8
+version=2.0.10
 description=Effective Anti-bot plugin for Velocity, BungeeCord, and Bukkit (1.7-latest)
@@ -1,6 +1,6 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.3-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.4-bin.zip
 networkTimeout=10000
 validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
@@ -45,6 +45,8 @@ public final class AttackTracker implements JVMProfiler {
    private int peakJoinsPerSecond;
    private double peakProcessCPUUsage;
    private long peakProcessMemoryUsage;
+    // Calculate during-attack-statistics using their deltas
+    private int successfulVerifications, failedVerifications;
  }

  public void checkIfUnderAttack() {
@@ -62,6 +64,8 @@ public final class AttackTracker implements JVMProfiler {
      // An attack has been detected
      if (currentAttack == null) {
        currentAttack = new AttackStatistics();
+        currentAttack.successfulVerifications = Sonar.get().getVerifiedPlayerController().estimatedSize();
+        currentAttack.failedVerifications = Statistics.FAILED_VERIFICATIONS.get();
        Sonar.get().getEventManager().publish(new AttackDetectedEvent());
      } else {
        // Reset attack timer if we're still under attack
@@ -101,8 +105,11 @@ public final class AttackTracker implements JVMProfiler {
          final String startTimestamp = String.valueOf(currentAttack.duration.getStart() / 1000L);
          final String endTimestamp = String.valueOf(System.currentTimeMillis() / 1000L);
          final long blacklisted = Sonar.get().getFallback().getBlacklisted().estimatedSize();
-          final long verified = Sonar.get().getVerifiedPlayerController().estimatedSize();
-          final long failed = Statistics.FAILED_VERIFICATIONS.get();
+          // Calculate during-attack-statistics using their deltas
+          final long totalVerified = Sonar.get().getVerifiedPlayerController().estimatedSize();
+          final long verified = Math.max(totalVerified - currentAttack.successfulVerifications, 0);
+          final long totalFailed = Statistics.FAILED_VERIFICATIONS.get();
+          final long failed = Math.max(totalFailed - currentAttack.failedVerifications, 0);

          // Post webhook to Discord
          Optional.ofNullable(Sonar.get().getConfig().getDiscordWebhook()).ifPresent(webhook -> webhook.post(() -> {
@@ -28,8 +28,6 @@ import xyz.jonesdev.sonar.api.command.subcommand.argument.Argument;
 import java.net.InetAddress;
 import java.net.UnknownHostException;
 import java.util.Arrays;
-import java.util.Objects;
-import java.util.regex.Pattern;
 import java.util.stream.Collectors;

@Getter
@@ -51,18 +49,7 @@ public abstract class Subcommand {
      .collect(Collectors.joining(", "));
  }

-  // https://stackoverflow.com/questions/5284147/validating-ipv4-addresses-with-regexp
-  private static final Pattern IP_PATTERN = Pattern.compile("^((25[0-5]|(2[0-4]|1\\d|[1-9]|)\\d)\\.?\\b){4}$");
-
  protected static @Nullable InetAddress getInetAddressIfValid(final InvocationSource source, final String rawIP) {
-    // We perform a regex check beforehand,
-    // so we don't have to create a new InetAddress,
-    // therefore, potentially saving some performance.
-    if (!IP_PATTERN.matcher(Objects.requireNonNull(rawIP)).matches()) {
-      source.sendMessage(SONAR.getConfig().getCommands().getIncorrectIpAddress());
-      return null;
-    }
-
    final InetAddress inetAddress;
    try {
      inetAddress = InetAddress.getByName(rawIP);
@@ -72,7 +59,7 @@ public abstract class Subcommand {
        return null;
      }
    } catch (UnknownHostException exception) {
-      source.sendMessage(SONAR.getConfig().getCommands().getUnknownIpAddress());
+      source.sendMessage(SONAR.getConfig().getCommands().getIncorrectIpAddress());
      return null;
    }
    return inetAddress;
@@ -112,4 +112,9 @@ public final class SimpleYamlConfig {
    yaml.addDefault(path, def);
    return yaml.getStringList(path);
  }
+
+  public List<Integer> getIntList(final String path, final List<Integer> def) {
+    yaml.addDefault(path, def);
+    return yaml.getIntegerList(path);
+  }
 }
@@ -29,10 +29,7 @@ import xyz.jonesdev.sonar.api.webhook.DiscordWebhook;

 import java.io.File;
 import java.net.InetAddress;
-import java.util.Arrays;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.List;
+import java.util.*;
 import java.util.regex.Pattern;

 import static xyz.jonesdev.sonar.api.Sonar.LINE_SEPARATOR;
@@ -51,8 +48,6 @@ public final class SonarConfiguration {
  @Getter
  private final Verification verification = new Verification();
  @Getter
-  private final Lockdown lockdown = new Lockdown();
-  @Getter
  private final Database database = new Database();
  @Getter
  private final Webhook webhook = new Webhook();
@@ -101,12 +96,49 @@ public final class SonarConfiguration {
    private Timing timing;

    @Getter
-    @RequiredArgsConstructor
    public enum Timing {
      ALWAYS, DURING_ATTACK, NEVER
    }

-    private boolean checkGravity;
+    private final Map map = new Map();
+    private final Gravity gravity = new Gravity();
+
+    @Getter
+    public static final class Map {
+      private boolean enabled;
+      private boolean drawBackgroundNoise;
+      private boolean randomizePositions;
+      private boolean randomizeFontSize;
+      private int precomputeAmount;
+      private int maxDuration;
+      private int maxTries;
+      private String dictionary;
+      private Component enterCode;
+      private Component failedCaptcha;
+      private String enterCodeActionBar;
+    }
+
+    @Getter
+    public static final class Gravity {
+      private boolean enabled;
+      private Gamemode gamemode;
+      private int maxMovementTicks;
+      private int maxIgnoredTicks;
+      private Component youAreBeingChecked;
+
+      @Getter
+      @RequiredArgsConstructor
+      public enum Gamemode {
+        SURVIVAL(0),
+        CREATIVE(1),
+        ADVENTURE(2),
+        // Keep this for backwards compatibility
+        SPECTATOR(2);
+
+        private final int id;
+      }
+    }
+
    private boolean logConnections;
    private boolean logDuringAttack;
    private boolean debugXYZPositions;
@@ -118,27 +150,13 @@ public final class SonarConfiguration {
    private String successLog;
    private String blacklistLog;

-    private Gamemode gamemode;
-
-    @Getter
-    @RequiredArgsConstructor
-    public enum Gamemode {
-      SURVIVAL(0),
-      CREATIVE(1),
-      ADVENTURE(2),
-      SPECTATOR(3);
-
-      private final int id;
-    }
-
    private int maxBrandLength;
-    private int maxMovementTicks;
-    private int maxIgnoredTicks;
-    private int maxVerifyingPlayers;
    private int maxLoginPackets;
    private int maxPing;
    private int readTimeout;
    private int reconnectDelay;
+    private final Collection<Integer> whitelistedProtocols = new HashSet<>(0);
+    private final Collection<Integer> blacklistedProtocols = new HashSet<>(0);

    private Component tooManyPlayers;
    private Component tooFastReconnect;
@@ -150,6 +168,7 @@ public final class SonarConfiguration {
    private Component alreadyVerifying;
    private Component alreadyQueued;
    private Component blacklisted;
+    private Component protocolBlacklisted;
  }

  @Getter
@@ -158,7 +177,6 @@ public final class SonarConfiguration {
    private String incorrectCommandUsage;
    private String incorrectIpAddress;
    private String illegalIpAddress;
-    private String unknownIpAddress;
    private String subCommandNoPerm;
    private String playersOnly;
    private String consoleOnly;
@@ -220,21 +238,6 @@ public final class SonarConfiguration {
    private String password;
  }

-  @Getter
-  @NoArgsConstructor(access = AccessLevel.PRIVATE)
-  public static final class Lockdown {
-    @Setter
-    private boolean enabled;
-    private boolean notifyAdmins;
-    private boolean logAttempts;
-    private Component disconnect;
-    private String bypassPermission;
-    private String activated;
-    private String deactivated;
-    private String notification;
-    private String consoleLog;
-  }
-
  @Getter
  @NoArgsConstructor(access = AccessLevel.PRIVATE)
  public static final class Webhook {
@@ -368,27 +371,6 @@ public final class SonarConfiguration {
      "Password for authenticating with the SQL database");
    database.password = generalConfig.getString("database.password", "");

-    // Lockdown
-    generalConfig.getYaml().setComment("lockdown",
-      "You can lock your server down using '/sonar lockdown' if, for example,"
-        + LINE_SEPARATOR + "bots are bypassing the verification or any other reason");
-    generalConfig.getYaml().setComment("lockdown.enabled",
-      "Should Sonar prevent all players from joining the server?");
-    lockdown.enabled = generalConfig.getBoolean("lockdown.enabled", false);
-
-    generalConfig.getYaml().setComment("lockdown.log-attempts",
-      "Should Sonar log new login attempts during lockdown?");
-    lockdown.logAttempts = generalConfig.getBoolean("lockdown.log-attempts", true);
-
-    generalConfig.getYaml().setComment("lockdown.notify-admins",
-      "Should Sonar notify admins when they join the server during lockdown?");
-    lockdown.notifyAdmins = generalConfig.getBoolean("lockdown.notify-admins", true);
-
-    generalConfig.getYaml().setComment("lockdown.bypass-permission",
-      "Which permission does a player need in order to bypass the lockdown mode?"
-        + LINE_SEPARATOR + "Players with this permission will also receive admin notifications when joining");
-    lockdown.bypassPermission = generalConfig.getString("lockdown.bypass-permission", "sonar.lockdown.bypass");
-
    // Queue
    generalConfig.getYaml().setComment("queue",
      "Every new login request will be queued to avoid spam join attacks"
@@ -415,17 +397,65 @@ public final class SonarConfiguration {
        + LINE_SEPARATOR + "All predicted motions are precalculated in order to save performance");
    generalConfig.getYaml().setComment("verification.checks.gravity.enabled",
      "Should Sonar check for valid client gravity? (Recommended)");
-    verification.checkGravity = generalConfig.getBoolean("verification.checks.gravity.enabled", true);
+    verification.gravity.enabled = generalConfig.getBoolean("verification.checks.gravity.enabled", true);

    generalConfig.getYaml().setComment("verification.checks.gravity.max-movement-ticks",
      "Maximum number of ticks the player has to fall in order to be allowed to hit the platform");
-    verification.maxMovementTicks = clamp(generalConfig.getInt("verification.checks.gravity.max-movement-ticks", 8),
+    verification.gravity.maxMovementTicks = clamp(generalConfig.getInt("verification.checks.gravity" +
+        ".max-movement-ticks", 8),
      2, 100);

    generalConfig.getYaml().setComment("verification.checks.gravity.max-ignored-ticks",
      "Maximum number of ignored Y movement changes before a player fails verification");
-    verification.maxIgnoredTicks = clamp(generalConfig.getInt("verification.checks.gravity.max-ignored-ticks", 5), 1,
-      128);
+    verification.gravity.maxIgnoredTicks = clamp(generalConfig.getInt("verification.checks.gravity.max-ignored-ticks"
+        , 5),
+      1, 128);
+
+    generalConfig.getYaml().setComment("verification.checks.gravity.gamemode",
+      "The gamemode of the player during verification"
+        + LINE_SEPARATOR + "Possible types: SURVIVAL, CREATIVE, ADVENTURE, SPECTATOR"
+        + LINE_SEPARATOR + "- SURVIVAL: all UI components are visible"
+        + LINE_SEPARATOR + "- CREATIVE: health and hunger are hidden"
+        + LINE_SEPARATOR + "- ADVENTURE: all UI components are visible");
+    verification.gravity.gamemode = Verification.Gravity.Gamemode.valueOf(
+      generalConfig.getString("verification.checks.gravity.gamemode", Verification.Gravity.Gamemode.ADVENTURE.name()).toUpperCase());
+
+    generalConfig.getYaml().setComment("verification.checks.map-captcha",
+      "Make the player type a code from a virtual map in chat after the gravity check");
+    generalConfig.getYaml().setComment("verification.checks.map-captcha.enabled",
+      "Should Sonar make the player pass a captcha?");
+    verification.map.enabled = generalConfig.getBoolean("verification.checks.map-captcha.enabled", false);
+
+    generalConfig.getYaml().setComment("verification.checks.map-captcha.background-noise",
+      "Should Sonar draw a white/light gray rectangle behind the captcha?");
+    verification.map.drawBackgroundNoise = generalConfig.getBoolean("verification.checks.map-captcha" +
+      ".background-noise", true);
+
+    generalConfig.getYaml().setComment("verification.checks.map-captcha.random-position",
+      "Should Sonar randomize the X and Y position of the captcha?");
+    verification.map.randomizePositions = generalConfig.getBoolean("verification.checks.map-captcha.random-position",
+      true);
+
+    generalConfig.getYaml().setComment("verification.checks.map-captcha.random-font-size",
+      "Should Sonar randomize the size of the font used for rendering the captcha?");
+    verification.map.randomizeFontSize = generalConfig.getBoolean("verification.checks.map-captcha.random-font-size",
+      true);
+
+    generalConfig.getYaml().setComment("verification.checks.map-captcha.precompute",
+      "How many answers should Sonar precompute (prepare)?");
+    verification.map.precomputeAmount = generalConfig.getInt("verification.checks.map-captcha.precompute", 1000);
+
+    generalConfig.getYaml().setComment("verification.checks.map-captcha.max-duration",
+      "How long should Sonar wait until the player fails the captcha?");
+    verification.map.maxDuration = generalConfig.getInt("verification.checks.map-captcha.max-duration", 45000);
+
+    generalConfig.getYaml().setComment("verification.checks.map-captcha.max-tries",
+      "How many times must a player fail the captcha before failing the verification?");
+    verification.map.maxTries = generalConfig.getInt("verification.checks.map-captcha.max-tries", 3);
+
+    generalConfig.getYaml().setComment("verification.checks.map-captcha.dictionary",
+      "Characters (letters and numbers) that are allowed to appear in the answer to the captcha");
+    verification.map.dictionary = generalConfig.getString("verification.checks.map-captcha.dictionary", "123456789");

    generalConfig.getYaml().setComment("verification.checks.valid-name-regex",
      "Regex for validating usernames during verification");
@@ -454,16 +484,6 @@ public final class SonarConfiguration {
      "Maximum number of login packets the player has to send in order to be kicked");
    verification.maxLoginPackets = clamp(generalConfig.getInt("verification.checks.max-login-packets", 256), 128, 8192);

-    generalConfig.getYaml().setComment("verification.gamemode",
-      "The gamemode of the player during verification"
-        + LINE_SEPARATOR + "Possible types: SURVIVAL, CREATIVE, ADVENTURE, SPECTATOR"
-        + LINE_SEPARATOR + "- SURVIVAL: all UI components are visible"
-        + LINE_SEPARATOR + "- CREATIVE: health and hunger are hidden"
-        + LINE_SEPARATOR + "- ADVENTURE: all UI components are visible"
-        + LINE_SEPARATOR + "- SPECTATOR: all UI components are hidden (Recommended)");
-    verification.gamemode = Verification.Gamemode.valueOf(
-      generalConfig.getString("verification.gamemode", Verification.Gamemode.SPECTATOR.name()).toUpperCase());
-
    generalConfig.getYaml().setComment("verification.log-connections",
      "Should Sonar log new verification attempts?");
    verification.logConnections = generalConfig.getBoolean("verification.log-connections", true);
@@ -481,16 +501,25 @@ public final class SonarConfiguration {
      "Amount of time that has to pass before a player times out");
    verification.readTimeout = clamp(generalConfig.getInt("verification.read-timeout", 3500), 500, 30000);

-    generalConfig.getYaml().setComment("verification.max-players",
-      "Maximum number of players verifying at the same time");
-    verification.maxVerifyingPlayers = clamp(generalConfig.getInt("verification.max-players", 1024), 1,
-      Short.MAX_VALUE);
-
    generalConfig.getYaml().setComment("verification.rejoin-delay",
      "Minimum number of rejoin delay during verification");
    verification.reconnectDelay = clamp(generalConfig.getInt("verification.rejoin-delay", 8000), 0, 100000);

-    // Webhooks
+    generalConfig.getYaml().setComment("verification.whitelisted-protocols",
+      "List of protocol IDs which are not checked by Sonar (verification bypass)"
+        + LINE_SEPARATOR + "You can find the full list of all protocol IDs here:"
+        + LINE_SEPARATOR + "https://wiki.vg/Protocol_version_numbers"
+        + LINE_SEPARATOR + "For example, Minecraft 1.20 has the ID 763.");
+    verification.whitelistedProtocols.clear();
+    verification.whitelistedProtocols.addAll(generalConfig.getIntList("verification.whitelisted-protocols",
+      new ArrayList<>(0)));
+
+    generalConfig.getYaml().setComment("verification.blacklisted-protocols",
+      "List of protocol IDs which are unable to join the server at all");
+    verification.blacklistedProtocols.clear();
+    verification.blacklistedProtocols.addAll(generalConfig.getIntList("verification.blacklisted-protocols",
+      new ArrayList<>(0)));
+
    generalConfig.getYaml().setComment("webhook",
      "Bot attack notifications can also be sent to your Discord server using webhooks");
    generalConfig.getYaml().setComment("webhook.url",
@@ -605,7 +634,7 @@ public final class SonarConfiguration {
      "%prefix%<red>Usage: /sonar %usage%"));

    messagesConfig.getYaml().setComment("commands.invalid-ip-address",
-      "Message that is shown when someone provides an invalid IP address (Invalid characters)");
+      "Message that is shown when someone provides an invalid IP address (Invalid format)");
    commands.incorrectIpAddress = formatString(messagesConfig.getString("commands.invalid-ip-address",
      "%prefix%The IP address you provided seems to be invalid."));

@@ -614,11 +643,6 @@ public final class SonarConfiguration {
    commands.illegalIpAddress = formatString(messagesConfig.getString("commands.illegal-ip-address",
      "%prefix%The IP address you provided seems to be either a local or loopback IP."));

-    messagesConfig.getYaml().setComment("commands.unknown-ip-address",
-      "Message that is shown when someone provides an unknown IP address (Unknown Host)");
-    commands.unknownIpAddress = formatString(messagesConfig.getString("commands.unknown-ip-address",
-      "%prefix%The IP address you provided seems to be unknown."));
-
    messagesConfig.getYaml().setComment("commands.player-only",
      "Message that is shown when the console runs a command that is player-only");
    commands.playersOnly = formatString(messagesConfig.getString("commands.player-only",
@@ -641,29 +665,6 @@ public final class SonarConfiguration {
    commands.subCommandNoPerm = formatString(messagesConfig.getString("commands.subcommand-no-permission",
      "%prefix%<red>You do not have permission to execute this subcommand. <gray>(%permission%)"));

-    messagesConfig.getYaml().setComment("lockdown",
-      "Translations for '/sonar lockdown'");
-    messagesConfig.getYaml().setComment("lockdown.notification",
-      "Message that is shown when an admin joins the server during lockdown");
-    lockdown.notification = formatString(messagesConfig.getString("lockdown.notification",
-      "%prefix%<green>Hey, the server is currently in lockdown mode. If you want to disable the lockdown mode,"
-        + " type <white>/sonar lockdown<green>."
-    ));
-
-    messagesConfig.getYaml().setComment("lockdown.console-log",
-      "Message that is shown to console when a normal player tries joining the server during lockdown");
-    lockdown.consoleLog = messagesConfig.getString("lockdown.console-log",
-      "%player% (%ip%, %protocol%) tried to join during lockdown mode.");
-
-    messagesConfig.getYaml().setComment("lockdown.disconnect-message",
-      "Message that is shown to a normal player when they try joining the server during lockdown");
-    lockdown.disconnect = deserialize(fromList(messagesConfig.getStringList("lockdown.disconnect-message",
-      Arrays.asList(
-        "%header%",
-        "<red>The server is currently locked down, please try again later.",
-        "%footer%"
-      ))));
-
    messagesConfig.getYaml().setComment("commands.main",
      "Translations for '/sonar'");
    messagesConfig.getYaml().setComment("commands.main.header",
@@ -703,18 +704,6 @@ public final class SonarConfiguration {
    commands.reloaded = formatString(messagesConfig.getString("commands.reload.finish",
      "%prefix%<green>Successfully reloaded <gray>(%taken%ms)"));

-    messagesConfig.getYaml().setComment("commands.lockdown",
-      "Translations for '/sonar lockdown'");
-    messagesConfig.getYaml().setComment("commands.lockdown.enabled",
-      "Message that is shown when a player enables server lockdown");
-    lockdown.activated = formatString(messagesConfig.getString("commands.lockdown.enabled",
-      "%prefix%The server is now in lockdown mode."));
-
-    messagesConfig.getYaml().setComment("commands.lockdown.disabled",
-      "Message that is shown when a player disables server lockdown");
-    lockdown.deactivated = formatString(messagesConfig.getString("commands.lockdown.disabled",
-      "%prefix%The server is no longer in lockdown mode."));
-
    messagesConfig.getYaml().setComment("commands.verbose",
      "Translations for '/sonar verbose'");
    messagesConfig.getYaml().setComment("commands.verbose.subscribed",
@@ -883,6 +872,25 @@ public final class SonarConfiguration {
    verification.successLog = formatString(messagesConfig.getString("verification.logs.successful",
      "%name% has been verified successfully (%time%s!)."));

+    messagesConfig.getYaml().setComment("verification.welcome",
+      "Message that is shown to the player when they are being checked for valid gravity");
+    verification.gravity.youAreBeingChecked = deserialize(formatString(messagesConfig.getString("verification.welcome",
+      "%prefix%<gray>Please wait a moment for the verification to finish...")));
+
+    messagesConfig.getYaml().setComment("verification.captcha.enter-code",
+      "Message that is shown to the player when they have to enter the answer to the captcha");
+    verification.map.enterCode = deserialize(formatString(messagesConfig.getString("verification.captcha.enter-code",
+      "%prefix%<green>Please enter the code in chat that is displayed on the map.")));
+    messagesConfig.getYaml().setComment("verification.captcha.action-bar",
+      "Timer that is shown to the player when they have to enter the answer to the captcha"
+        + LINE_SEPARATOR + "(Set this to '' to disable the action bar message)");
+    verification.map.enterCodeActionBar = formatString(messagesConfig.getString("verification.captcha.action-bar",
+      "%prefix%<green>You have %time-left% seconds left to enter the code in chat"));
+    messagesConfig.getYaml().setComment("verification.captcha.incorrect",
+      "Message that is shown to the player when they enter the wrong answer in chat");
+    verification.map.failedCaptcha = deserialize(formatString(messagesConfig.getString("verification.captcha.incorrect",
+      "%prefix%<red>You have entered the wrong code. Please try again.")));
+
    messagesConfig.getYaml().setComment("verification.too-many-players",
      "Disconnect message that is shown when too many players are verifying at the same time");
    verification.tooManyPlayers = deserialize(fromList(messagesConfig.getStringList("verification.too-many-players",
@@ -952,6 +960,17 @@ public final class SonarConfiguration {
        "%footer%"
      ))));

+    messagesConfig.getYaml().setComment("verification.blacklisted-protocol",
+      "Disconnect message that is shown when someone joins with a blacklisted version");
+    verification.protocolBlacklisted = deserialize(fromList(messagesConfig.getStringList("verification" +
+        ".blacklisted-protocol",
+      Arrays.asList(
+        "%header%",
+        "<red>You are using a version that is not allowed on our server.",
+        "<gold>Need help logging in? <gray>%support-url%",
+        "%footer%"
+      ))));
+
    messagesConfig.getYaml().setComment("verification.already-online",
      "Disconnect message that is shown when someone tries verifying with an account that is online");
    verification.alreadyConnected = deserialize(fromList(messagesConfig.getStringList("verification.already-online",
@@ -40,11 +40,10 @@ public final class Fallback {
  public static final Fallback INSTANCE = new Fallback();
  private static final @NotNull Sonar SONAR = Objects.requireNonNull(Sonar.get());

-  private final Map<String, InetAddress> connected = new ConcurrentHashMap<>();
+  private final Map<String, InetAddress> connected = new ConcurrentHashMap<>(64, 0.75f);
  // Only block the player for a few minutes to avoid issues
-  private final ExpiringCache<String> blacklisted = Cappuccino.buildExpiring(
-    10L, TimeUnit.MINUTES, 5000L
-  );
+  private final ExpiringCache<InetAddress> blacklisted = Cappuccino.buildExpiring(
+    10L, TimeUnit.MINUTES, 5000L);
  private final @NotNull FallbackQueue queue = FallbackQueue.INSTANCE;
  private final @NotNull FallbackRatelimiter ratelimiter = FallbackRatelimiter.INSTANCE;

@@ -69,5 +69,7 @@ public final class FallbackQueue {

    // Run the attack check task
    Sonar.get().getAttackTracker().checkIfUnderAttack();
+    // Clean up the cache of rate-limited IPs
+    Sonar.get().getFallback().getRatelimiter().cleanUpCache();
  }
 }
@@ -31,6 +31,15 @@ public final class FallbackRatelimiter {
  @Setter
  private ExpiringCache<InetAddress> expiringCache;

+  /**
+   * We don't want to clean up the cache in the
+   * {@link #attempt(InetAddress)} method because
+   * it would take up too many resources.
+   */
+  public void cleanUpCache() {
+    expiringCache.cleanUp(false);
+  }
+
  /**
   * Checks if the player has tried verifying too fast
   *
@@ -39,11 +48,9 @@ public final class FallbackRatelimiter {
   */
  @SuppressWarnings("BooleanMethodIsAlwaysInverted")
  public boolean attempt(final @NotNull InetAddress inetAddress) {
-    // Clean up the cache
-    expiringCache.cleanUp(false);
-
    // Cache the IP address if it's not already cached
    if (!expiringCache.has(inetAddress)) {
+      // Cache the IP address
      expiringCache.put(inetAddress);
      return true;
    }
@@ -115,7 +115,7 @@ public interface FallbackUser<X, Y> {
      // Call the BotBlacklistedEvent for external API usage
      Sonar.get().getEventManager().publish(new UserBlacklistedEvent(this));

-      getFallback().getBlacklisted().put(getInetAddress().toString());
+      getFallback().getBlacklisted().put(getInetAddress());
      getFallback().getLogger().info(Sonar.get().getConfig().getVerification().getBlacklistLog()
        .replace("%ip%", Sonar.get().getConfig().formatAddress(getInetAddress()))
        .replace("%protocol%", String.valueOf(getProtocolVersion().getProtocol())));
@@ -22,6 +22,7 @@ import lombok.RequiredArgsConstructor;

 import java.util.*;

+@Getter
@RequiredArgsConstructor
 public enum ProtocolVersion {
  UNKNOWN(-1),
@@ -64,9 +65,9 @@ public enum ProtocolVersion {
  MINECRAFT_1_19_3(761),
  MINECRAFT_1_19_4(762),
  MINECRAFT_1_20(763),
-  MINECRAFT_1_20_2(764);
+  MINECRAFT_1_20_2(764),
+  MINECRAFT_1_20_3(765);

-  @Getter
  private final int protocol;

  public static final ProtocolVersion MINIMUM_VERSION = MINECRAFT_1_7_2;
@@ -95,7 +96,7 @@ public enum ProtocolVersion {
      }

      SUPPORTED_VERSIONS = Collections.unmodifiableSet(versions);
-      LATEST_VERSION = new ArrayList<>(versions).get(versions.size() - 1);
+      LATEST_VERSION = (ProtocolVersion) versions.toArray()[versions.size() - 1];
    }
  }

@@ -18,12 +18,14 @@
 package xyz.jonesdev.sonar.bungee.fallback;

 import io.netty.channel.ChannelHandlerContext;
+import io.netty.handler.codec.haproxy.HAProxyMessage;
 import net.md_5.bungee.api.ProxyServer;
 import net.md_5.bungee.connection.DownstreamBridge;
 import net.md_5.bungee.connection.UpstreamBridge;
 import net.md_5.bungee.netty.ChannelWrapper;
 import net.md_5.bungee.netty.HandlerBoss;
 import net.md_5.bungee.netty.PacketHandler;
+import net.md_5.bungee.protocol.PacketWrapper;
 import org.jetbrains.annotations.NotNull;

 public final class FallbackHandlerBoss extends HandlerBoss {
@@ -60,6 +62,13 @@ public final class FallbackHandlerBoss extends HandlerBoss {
    }
  }

+  @Override
+  public void channelRead(final ChannelHandlerContext ctx, final Object msg) throws Exception {
+    if (msg instanceof HAProxyMessage || msg instanceof PacketWrapper) {
+      super.channelRead(ctx, msg);
+    }
+  }
+
  @Override
  public void exceptionCaught(final @NotNull ChannelHandlerContext ctx, final Throwable throwable) throws Exception {
    if (ctx.channel().isActive()) {
@@ -20,6 +20,7 @@ package xyz.jonesdev.sonar.bungee.fallback;
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelFutureListener;
 import io.netty.channel.ChannelPipeline;
+import io.netty.handler.codec.CorruptedFrameException;
 import io.netty.handler.codec.DecoderException;
 import lombok.Getter;
 import lombok.val;
@@ -94,7 +95,7 @@ public final class FallbackInitialHandler extends InitialHandler {
  public void handle(final StatusRequest statusRequest) throws Exception {
    // Fix status packet spam exploit
    if (receivedStatusPacket) {
-      throw new ConditionFailedException("Duplicate status packet");
+      throw new CorruptedFrameException("Duplicate status packet");
    }
    receivedStatusPacket = true;
    // Run the rest of the method asynchronously
@@ -102,7 +103,7 @@ public final class FallbackInitialHandler extends InitialHandler {
      // The channel always stays open because the client sends
      // a StatusRequest and a Ping packet after one another
      if (!isConnected()) {
-        throw new ConditionFailedException("Not connected anymore");
+        throw new CorruptedFrameException("Not connected anymore");
      }
      try {
        super.handle(statusRequest);
@@ -119,11 +120,12 @@ public final class FallbackInitialHandler extends InitialHandler {

    // Fix login packet spam exploit
    if (receivedLoginPacket || user != null) {
-      throw new ConditionFailedException("Duplicate login packet");
+      throw new CorruptedFrameException("Duplicate login packet");
    }
    receivedLoginPacket = true;
    // Cache protocol version so other handlers don't throw NPEs
-    protocolVersion = ProtocolVersion.fromId(getHandshake().getProtocolVersion());
+    final int protocolId = getHandshake().getProtocolVersion();
+    protocolVersion = ProtocolVersion.fromId(protocolId);
    final Channel channel = channelWrapper.getHandle();

    // Run in the channel's event loop
@@ -135,26 +137,19 @@ public final class FallbackInitialHandler extends InitialHandler {
        // Increase total traffic statistic
        Statistics.TOTAL_TRAFFIC.increment();

+        final InetAddress inetAddress = getAddress().getAddress();
+        // Check the blacklist here since we cannot let the player "ghost join"
+        if (FALLBACK.getBlacklisted().has(inetAddress)) {
+          closeWith(getKickPacket(Sonar.get().getConfig().getVerification().getBlacklisted()));
+          return;
+        }
+
        // Check if the verification is enabled
        if (!Sonar.get().getFallback().shouldVerifyNewPlayers()) {
          super.handle(loginRequest);
          return;
        }

-        final InetAddress inetAddress = getAddress().getAddress();
-        val uuid = UUID.nameUUIDFromBytes(("OfflinePlayer:" + loginRequest.getData()).getBytes(StandardCharsets.UTF_8));
-        // Check if the player is already verified
-        if (Sonar.get().getVerifiedPlayerController().has(inetAddress, uuid)) {
-          super.handle(loginRequest);
-          return;
-        }
-
-        // Check the blacklist here since we cannot let the player "ghost join"
-        if (FALLBACK.getBlacklisted().has(inetAddress.toString())) {
-          closeWith(getKickPacket(Sonar.get().getConfig().getVerification().getBlacklisted()));
-          return;
-        }
-
        // Completely skip Geyser connections
        if (isGeyserConnection(channel)) {
          FALLBACK.getLogger().info("Skipping Geyser player: {}{}",
@@ -163,6 +158,25 @@ public final class FallbackInitialHandler extends InitialHandler {
          return;
        }

+        // Check if the protocol ID of the player is not allowed to enter the server
+        if (Sonar.get().getConfig().getVerification().getBlacklistedProtocols().contains(protocolId)) {
+          closeWith(getKickPacket(Sonar.get().getConfig().getVerification().getProtocolBlacklisted()));
+          return;
+        }
+
+        val uuid = UUID.nameUUIDFromBytes(("OfflinePlayer:" + loginRequest.getData()).getBytes(StandardCharsets.UTF_8));
+        // Check if the player is already verified
+        if (Sonar.get().getVerifiedPlayerController().has(inetAddress, uuid)) {
+          super.handle(loginRequest);
+          return;
+        }
+
+        // Check if the protocol ID of the player is allowed to bypass verification
+        if (Sonar.get().getConfig().getVerification().getWhitelistedProtocols().contains(protocolId)) {
+          super.handle(loginRequest);
+          return;
+        }
+
        // Create wrapped Fallback user
        user = new FallbackUserWrapper(
          FALLBACK, channelWrapper, this,
@@ -202,13 +216,6 @@ public final class FallbackInitialHandler extends InitialHandler {
          return;
        }

-        // We cannot allow too many players on our Fallback server
-        // There's technically no reason for limiting this, but we'll better stay safe.
-        if (FALLBACK.getConnected().size() > Sonar.get().getConfig().getVerification().getMaxVerifyingPlayers()) {
-          closeWith(getKickPacket(Sonar.get().getConfig().getVerification().getTooManyPlayers()));
-          return;
-        }
-
        // Check if the IP address is currently being rate-limited
        if (!FALLBACK.getRatelimiter().attempt(inetAddress)) {
          closeWith(getKickPacket(Sonar.get().getConfig().getVerification().getTooFastReconnect()));
@@ -234,12 +241,9 @@ public final class FallbackInitialHandler extends InitialHandler {

          // Add better timeout handler to avoid known exploits or issues
          // We also want to timeout bots quickly to avoid flooding
-          pipeline.replace(
-            TIMEOUT_HANDLER,
-            TIMEOUT_HANDLER,
-            new FallbackTimeoutHandler(Sonar.get().getConfig().getVerification().getReadTimeout(),
-              TimeUnit.MILLISECONDS)
-          );
+          final int readTimeout = Sonar.get().getConfig().getVerification().getReadTimeout();
+          pipeline.replace(TIMEOUT_HANDLER, TIMEOUT_HANDLER,
+            new FallbackTimeoutHandler(readTimeout, TimeUnit.MILLISECONDS));

          // Disconnect if the protocol version could not be resolved
          if (user.getProtocolVersion().isUnknown()) {
@@ -298,10 +302,8 @@ public final class FallbackInitialHandler extends InitialHandler {
            ? FallbackPacketRegistry.CONFIG : FallbackPacketRegistry.GAME);

          // Replace normal decoder to allow custom packets
-          user.getPipeline().replace(
-            PACKET_DECODER, FALLBACK_PACKET_DECODER, new FallbackPacketDecoder(user,
-              new FallbackVerificationHandler(user, loginRequest.getData(), uuid)
-            ));
+          user.getPipeline().replace(PACKET_DECODER, FALLBACK_PACKET_DECODER,
+            new FallbackPacketDecoder(user, new FallbackVerificationHandler(user, loginRequest.getData(), uuid)));
        }));
      } catch (Throwable throwable) {
        throw new ReflectiveOperationException(throwable);
@@ -309,7 +311,7 @@ public final class FallbackInitialHandler extends InitialHandler {
    });
  }

-  private static final Map<Component, Kick> CACHED_KICK_PACKETS = new ConcurrentHashMap<>(16);
+  private static final Map<Component, Kick> CACHED_KICK_PACKETS = new ConcurrentHashMap<>(10);

  public static @NotNull Kick getKickPacket(final @NotNull Component component) {
    Kick cachedKickPacket = CACHED_KICK_PACKETS.get(component);
@@ -18,12 +18,8 @@
 package xyz.jonesdev.sonar.bungee.fallback;

 import lombok.RequiredArgsConstructor;
-import net.kyori.adventure.audience.Audience;
 import net.kyori.adventure.text.Component;
-import net.kyori.adventure.text.minimessage.MiniMessage;
-import net.md_5.bungee.api.connection.PendingConnection;
 import net.md_5.bungee.api.event.LoginEvent;
-import net.md_5.bungee.api.event.PostLoginEvent;
 import net.md_5.bungee.api.plugin.Listener;
 import net.md_5.bungee.event.EventHandler;
 import org.jetbrains.annotations.NotNull;
@@ -59,41 +55,4 @@ public final class FallbackListener implements Listener {
      }
    }
  }
-
-  @EventHandler
-  @SuppressWarnings("deprecation")
-  public void handle(final @NotNull PostLoginEvent event) {
-    if (Sonar.get().getConfig().getLockdown().isEnabled()) {
-      if (!event.getPlayer().hasPermission(Sonar.get().getConfig().getLockdown().getBypassPermission())) {
-        final PendingConnection pendingConnection = event.getPlayer().getPendingConnection();
-        // Try to close the channel with a custom serialized disconnect component
-        if (pendingConnection instanceof FallbackInitialHandler) {
-          final FallbackInitialHandler fallbackInitialHandler = (FallbackInitialHandler) pendingConnection;
-          final Component component = Sonar.get().getConfig().getLockdown().getDisconnect();
-          fallbackInitialHandler.closeWith(FallbackInitialHandler.getKickPacket(component));
-        } else {
-          // Fallback by disconnecting without a message
-          pendingConnection.disconnect();
-          Sonar.get().getLogger().warn("Fallback handler of {} is missing", event.getPlayer().getName());
-          return;
-        }
-
-        if (Sonar.get().getConfig().getLockdown().isLogAttempts()) {
-          Sonar.get().getLogger().info(Sonar.get().getConfig().getLockdown().getConsoleLog()
-            .replace("%player%", event.getPlayer().getName())
-            .replace("%ip%", Sonar.get().getConfig()
-              .formatAddress(event.getPlayer().getAddress().getAddress()))
-            .replace("%protocol%",
-              String.valueOf(event.getPlayer().getPendingConnection().getVersion())));
-        }
-      } else if (Sonar.get().getConfig().getLockdown().isNotifyAdmins()) {
-        final Audience audience = Sonar.get().getVerboseHandler().getAudiences().get(event.getPlayer().getName());
-        if (audience != null) {
-          final String notification = Sonar.get().getConfig().getLockdown().getNotification();
-          final Component deserialized = MiniMessage.miniMessage().deserialize(notification);
-          audience.sendMessage(deserialized);
-        }
-      }
-    }
-  }
 }
@@ -20,20 +20,25 @@ package xyz.jonesdev.sonar.common.fallback;
 import io.netty.buffer.ByteBuf;
 import io.netty.handler.codec.CorruptedFrameException;
 import io.netty.handler.codec.DecoderException;
-import lombok.Setter;
 import lombok.val;
+import net.kyori.adventure.text.minimessage.MiniMessage;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 import xyz.jonesdev.sonar.api.Sonar;
 import xyz.jonesdev.sonar.api.event.impl.UserVerifySuccessEvent;
 import xyz.jonesdev.sonar.api.fallback.FallbackUser;
 import xyz.jonesdev.sonar.api.model.VerifiedPlayer;
 import xyz.jonesdev.sonar.api.timer.SystemTimer;
 import xyz.jonesdev.sonar.common.fallback.protocol.*;
+import xyz.jonesdev.sonar.common.fallback.protocol.map.ItemMapType;
+import xyz.jonesdev.sonar.common.fallback.protocol.map.MapInfoPreparer;
+import xyz.jonesdev.sonar.common.fallback.protocol.map.PreparedMapInfo;
 import xyz.jonesdev.sonar.common.fallback.protocol.packets.config.FinishConfiguration;
 import xyz.jonesdev.sonar.common.fallback.protocol.packets.login.LoginAcknowledged;
 import xyz.jonesdev.sonar.common.fallback.protocol.packets.play.*;
 import xyz.jonesdev.sonar.common.utility.protocol.ProtocolUtil;

+import java.util.Objects;
 import java.util.Random;
 import java.util.UUID;
 import java.util.regex.Pattern;
@@ -44,22 +49,28 @@ import static xyz.jonesdev.sonar.api.fallback.protocol.ProtocolVersion.*;
 import static xyz.jonesdev.sonar.common.fallback.protocol.FallbackPreparer.*;

 public final class FallbackVerificationHandler implements FallbackPacketListener {
+  private static final Random RANDOM = new Random();
+
+  // General
+  private final SystemTimer login = new SystemTimer();
  private final @NotNull FallbackUser<?, ?> user;
  private final String username;
  private final UUID playerUuid;
+  private @NotNull State state = State.LOGIN_ACK; // 1.20.2
+
+  // Checks
  private short expectedTransactionId;
-  private long expectedKeepAliveId;
-  private int expectedTeleportId = -1;
-  private int tick, totalReceivedPackets;
-  private int ignoredMovementTicks;
+  private int expectedKeepAliveId, expectedTeleportId = -1;
+  private int tick, totalReceivedPackets, ignoredMovementTicks;
  private double posX, posY, posZ, lastY;
  private boolean resolvedClientBrand, resolvedClientSettings;
-  @Setter
-  private @NotNull State state = State.LOGIN_ACK;
  private boolean listenForMovements;

-  private final SystemTimer login = new SystemTimer();
-  private static final Random RANDOM = new Random();
+  // Map captcha
+  private final SystemTimer keepAlive = new SystemTimer();
+  private final SystemTimer actionBar = new SystemTimer();
+  private @Nullable PreparedMapInfo captcha;
+  private int captchaTriesLeft;

  public enum State {
    // 1.20.2 configuration state
@@ -70,6 +81,8 @@ public final class FallbackVerificationHandler implements FallbackPacketListener
    CLIENT_SETTINGS, PLUGIN_MESSAGE, TRANSACTION,
    // PLAY checks
    TELEPORT, POSITION,
+    // Captcha
+    MAP_CAPTCHA,
    // Done
    SUCCESS
  }
@@ -142,10 +155,11 @@ public final class FallbackVerificationHandler implements FallbackPacketListener
    final boolean v1_20_2 = user.getProtocolVersion().compareTo(MINECRAFT_1_20_2) >= 0;
    if (!v1_20_2) {
      // Set the state to CLIENT_SETTINGS to avoid false positives
-      // and go on with the flow of the verification.
+      // (1.20.2 needs the LOGIN_ACK state) and go on with
+      // the flow of the verification.
      state = State.CLIENT_SETTINGS;
    }
-    // Select the JoinGame packet for the respective protocol version
+    // Send the JoinGame packet so we can continue the verification
    user.write(joinGame);
    if (v1_20_2) {
      // Perform the transaction check since the ClientSettings
@@ -165,21 +179,37 @@ public final class FallbackVerificationHandler implements FallbackPacketListener
    // Teleport the player to the spawn position
    user.delayedWrite(new PositionLook(
      SPAWN_X_POSITION, dynamicSpawnYPosition, SPAWN_Z_POSITION,
-      0f, 0f, expectedTeleportId, false
-    ));
+      0f, -90f, expectedTeleportId, false));
+    // Make sure the player escapes the 1.18.2+ "Loading terrain" screen
+    if (user.getProtocolVersion().compareTo(MINECRAFT_1_18_2) >= 0) {
+      user.delayedWrite(dynamicSpawnPosition);
+    }
  }

  private void sendChunkData() {
    // Set the state to POSITION to avoid false positives
    // and go on with the flow of the verification.
    state = State.POSITION;
+    // 1.20.3 packets introduced game events
+    if (user.getProtocolVersion().compareTo(MINECRAFT_1_20_3) >= 0) {
+      // Make sure the client knows that we're sending chunks next
+      user.delayedWrite(START_WRITING_CHUNKS);
+    }
    // Teleport player into the fake lobby by sending an empty chunk
    user.delayedWrite(EMPTY_CHUNK_DATA);
    // Send an UpdateSectionBlocks packet with a platform of blocks
    // to check if the player collides with the solid platform.
    user.delayedWrite(updateSectionBlocks);
-    // Send all packets in one flush
-    user.getChannel().flush();
+    // Checking gravity is disabled, just finish verification
+    if (!Sonar.get().getConfig().getVerification().getGravity().isEnabled()) {
+      // Switch to captcha state if needed
+      captchaOrFinish();
+    } else {
+      // Make sure the player knows we are checking them
+      user.delayedWrite(youAreBeingChecked);
+      // Send all packets in one flush
+      user.getChannel().flush();
+    }
  }

  private static boolean validateClientLocale(final @SuppressWarnings("unused") @NotNull FallbackUser<?, ?> user,
@@ -216,13 +246,60 @@ public final class FallbackVerificationHandler implements FallbackPacketListener
  public void handle(final @NotNull FallbackPacket packet) {
    // The player has already been verified, drop all other packets
    if (state == State.SUCCESS) return;
+    // Check for timeout since the player could be sending packets but not important ones
+    final long timeout = Sonar.get().getConfig().getVerification().getMaxPing();
+    // We are expecting a captcha code in chat, drop all other packets
+    if (state == State.MAP_CAPTCHA) {
+      // Check if the player took too long to enter the captcha
+      final int maxDuration = Sonar.get().getConfig().getVerification().getMap().getMaxDuration();
+      checkFrame(!login.elapsed(maxDuration), "took too long to enter captcha");
+
+      // Handle incoming chat messages
+      if (packet instanceof Chat) {
+        final Chat chat = (Chat) packet;
+        Objects.requireNonNull(captcha);
+        if (!chat.getMessage().equals(captcha.getInfo().getAnswer())) {
+          // Captcha is incorrect
+          checkFrame(captchaTriesLeft-- > 0, "failed captcha too often");
+          user.write(incorrectCaptcha);
+          return;
+        }
+        // Captcha is correct
+        finish();
+        return;
+      }
+
+      // Every second
+      if (actionBar.elapsed(1000L)) {
+        final String actionBarMessage = Sonar.get().getConfig().getVerification().getMap().getEnterCodeActionBar();
+        // Only send action bar if the message is actually supposed to be sent
+        if (!actionBarMessage.isEmpty()) {
+          final String timeLeft = String.format("%.0f", (maxDuration - login.delay()) / 1000D);
+          user.write(new Chat(MiniMessage.miniMessage().deserialize(
+            actionBarMessage.replace("%time-left%", timeLeft)), Chat.GAME_INFO_TYPE));
+          // Make sure to reset the timer
+          actionBar.reset();
+        }
+      }
+
+      // Every about 10 seconds
+      if (keepAlive.elapsed(timeout)) {
+        // Send the message again to remind the player
+        user.delayedWrite(enterCodeMessage);
+        // Send a KeepAlive packet to prevent timeout
+        user.delayedWrite(CAPTCHA_KEEP_ALIVE);
+        // Send both packets in one flush
+        user.getChannel().flush();
+        // Make sure to reset the timer
+        keepAlive.reset();
+      }
+      return;
+    }

    // Check if the player is not sending a ton of packets to the server
    final int maxPackets = Sonar.get().getConfig().getVerification().getMaxLoginPackets() + maxMovementTick;
    checkFrame(++totalReceivedPackets < maxPackets, "too many packets");

-    // Check for timeout since the player could be sending packets but not important ones
-    final long timeout = Sonar.get().getConfig().getVerification().getMaxPing();
    // Check if the time limit has exceeded
    if (login.elapsed(timeout)) {
      user.getChannel().close();
@@ -321,18 +398,6 @@ public final class FallbackVerificationHandler implements FallbackPacketListener
      // Check if the transaction ID is valid
      checkFrame(transaction.getId() == expectedTransactionId, "invalid transaction id");

-      // Checking gravity is disabled, just finish verification
-      if (!Sonar.get().getConfig().getVerification().isCheckGravity()) {
-        finish();
-        return;
-      }
-
-      // TODO: implement ChunkData packet for 1.20.2
-      if (user.getProtocolVersion().compareTo(MINECRAFT_1_20_2) >= 0) {
-        finish();
-        return;
-      }
-
      // First, send an Abilities packet to the client to make
      // sure the player falls even in spectator mode.
      // Then, teleport the player to the spawn position.
@@ -422,7 +487,7 @@ public final class FallbackVerificationHandler implements FallbackPacketListener
    // We have to account for this or the player will fail the verification.
    if (deltaY == 0) {
      // Check for too many ignored Y ticks
-      final int maxIgnoredTicks = Sonar.get().getConfig().getVerification().getMaxIgnoredTicks();
+      final int maxIgnoredTicks = Sonar.get().getConfig().getVerification().getGravity().getMaxIgnoredTicks();
      checkFrame(++ignoredMovementTicks < maxIgnoredTicks, "too many ignored ticks");
      return;
    }
@@ -443,7 +508,7 @@ public final class FallbackVerificationHandler implements FallbackPacketListener

      // The player is colliding to blocks, finish verification
      if (ground) {
-        finish();
+        captchaOrFinish();
        return;
      }
    } else {
@@ -471,17 +536,41 @@ public final class FallbackVerificationHandler implements FallbackPacketListener
    tick++;
  }

-  private void assertState(final @NotNull State expectedState) {
-    if (expectedState != state) {
-      user.fail("expected " + expectedState + ", got " + state);
+  private void captchaOrFinish() {
+    if (Sonar.get().getConfig().getVerification().getMap().isEnabled()) {
+      // Set the state to MAP_CAPTCHA, so we don't handle any unnecessary packets
+      state = State.MAP_CAPTCHA;
+      if (!Sonar.get().getConfig().getVerification().getGravity().isEnabled()
+        && user.getProtocolVersion().compareTo(MINECRAFT_1_18_2) >= 0) {
+        // Make sure the player escapes the 1.18.2+ "Loading terrain" screen
+        user.delayedWrite(CAPTCHA_SPAWN_POSITION);
+      }
+      // Initialize the map captcha
+      handleMapCaptcha();
+    } else {
+      // Finish the verification
+      finish();
    }
  }

-  private void checkFrame(final boolean condition, final String message) {
-    if (!condition) {
-      user.fail(message);
-      throw new CorruptedFrameException(message);
-    }
+  private void handleMapCaptcha() {
+    // Reset max tries
+    captchaTriesLeft = Sonar.get().getConfig().getVerification().getMap().getMaxTries();
+
+    // Set slot to map
+    user.delayedWrite(new SetSlot(0, 36, 1, 0,
+      ItemMapType.FILLED_MAP.getId(user.getProtocolVersion()), SetSlot.MAP_NBT));
+    // Send random captcha to the player
+    captcha = MapInfoPreparer.getRandomCaptcha();
+    Objects.requireNonNull(captcha).write(user);
+    // Teleport the player to the position above the platform
+    user.delayedWrite(CAPTCHA_POSITION);
+    // Make sure the player cannot move
+    user.delayedWrite(CAPTCHA_ABILITIES);
+    // Make sure the player knows what to do
+    user.delayedWrite(enterCodeMessage);
+    // Send all packets in one flush
+    user.getChannel().flush();
  }

  private void finish() {
@@ -504,4 +593,26 @@ public final class FallbackVerificationHandler implements FallbackPacketListener
      .replace("%name%", username)
      .replace("%time%", login.toString()));
  }
+
+  /**
+   * Fails the verification if a certain state is unexpected.
+   *
+   * @param expectedState Expected state
+   */
+  private void assertState(final @NotNull State expectedState) {
+    checkFrame(state == expectedState, "expected " + expectedState + ", got " + state);
+  }
+
+  /**
+   * Checks if a certain condition is met, fails the verification if not.
+   *
+   * @param condition Condition to fail if it's false
+   * @param message   Messages displayed in the stacktrace
+   */
+  private void checkFrame(final boolean condition, final String message) {
+    if (!condition) {
+      user.fail(message);
+      throw new CorruptedFrameException(message);
+    }
+  }
 }
@@ -33,14 +33,13 @@ import static xyz.jonesdev.sonar.common.utility.protocol.VarIntUtil.readVarInt;
 public final class FallbackPacketDecoder extends ChannelInboundHandlerAdapter {
  private final FallbackUser<?, ?> user;
  private final FallbackPacketListener listener;
-  private @NotNull FallbackPacketRegistry.ProtocolRegistry registry;
+  private FallbackPacketRegistry.ProtocolRegistry registry;

  public FallbackPacketDecoder(final @NotNull FallbackUser<?, ?> user,
                               final @NotNull FallbackPacketListener listener) {
    this.user = user;
-    this.registry = (user.getProtocolVersion().compareTo(MINECRAFT_1_20_2) >= 0 ? LOGIN : GAME)
-      .getProtocolRegistry(SERVERBOUND, user.getProtocolVersion());
    this.listener = listener;
+    updateRegistry(user.getProtocolVersion().compareTo(MINECRAFT_1_20_2) >= 0 ? LOGIN : GAME);
  }

  public void updateRegistry(final @NotNull FallbackPacketRegistry registry) {
@@ -66,8 +65,7 @@ public final class FallbackPacketDecoder extends ChannelInboundHandlerAdapter {
      final int packetId = readVarInt(byteBuf);
      final FallbackPacket packet = registry.createPacket(packetId);

-      // If the packet hasn't been found, skip it
-      // TODO: Can we fail the verification afterwards?
+      // If the packet isn't found, skip it
      if (packet == null) {
        byteBuf.readerIndex(originalReaderIndex);
        return;
@@ -93,6 +91,9 @@ public final class FallbackPacketDecoder extends ChannelInboundHandlerAdapter {

        // Let our verification handler process the packet
        listener.handle(packet);
+
+        // Fire channel read to avoid timeout
+        ctx.fireChannelRead(packet);
      } finally {
        // Release the ByteBuf to avoid memory leaks
        byteBuf.release();
@@ -23,7 +23,7 @@ import lombok.Data;
 import org.jetbrains.annotations.NotNull;
 import xyz.jonesdev.sonar.api.fallback.protocol.ProtocolVersion;
 import xyz.jonesdev.sonar.common.fallback.protocol.packets.config.FinishConfiguration;
-import xyz.jonesdev.sonar.common.fallback.protocol.packets.config.RegistrySync;
+import xyz.jonesdev.sonar.common.fallback.protocol.packets.config.RegistryData;
 import xyz.jonesdev.sonar.common.fallback.protocol.packets.login.LoginAcknowledged;
 import xyz.jonesdev.sonar.common.fallback.protocol.packets.login.LoginSuccess;
 import xyz.jonesdev.sonar.common.fallback.protocol.packets.play.*;
@@ -48,13 +48,13 @@ public enum FallbackPacketRegistry {
  CONFIG {
    {
      clientbound.register(Disconnect.class, Disconnect::new,
-        map(0x01, MINECRAFT_1_20_2, false));
+        map(0x01, MINECRAFT_1_20_2, true));
      clientbound.register(FinishConfiguration.class, FinishConfiguration::new,
        map(0x02, MINECRAFT_1_20_2, false));
      clientbound.register(KeepAlive.class, KeepAlive::new,
        map(0x03, MINECRAFT_1_20_2, false));
-      clientbound.register(RegistrySync.class, RegistrySync::new,
-        map(0x05, MINECRAFT_1_20_2, false));
+      clientbound.register(RegistryData.class, RegistryData::new,
+        map(0x05, MINECRAFT_1_20_2, true));

      serverbound.register(ClientSettings.class, ClientSettings::new,
        map(0x00, MINECRAFT_1_20_2, false));
@@ -166,7 +166,8 @@ public enum FallbackPacketRegistry {
        map(0x40, MINECRAFT_1_19_1, true),
        map(0x3F, MINECRAFT_1_19_3, true),
        map(0x43, MINECRAFT_1_19_4, true),
-        map(0x45, MINECRAFT_1_20_2, true));
+        map(0x45, MINECRAFT_1_20_2, true),
+        map(0x47, MINECRAFT_1_20_3, true));
      clientbound.register(Transaction.class, Transaction::new,
        map(0x32, MINECRAFT_1_7_2, true),
        map(0x11, MINECRAFT_1_9, true),
@@ -180,19 +181,73 @@ public enum FallbackPacketRegistry {
        map(0x2E, MINECRAFT_1_19_3, true),
        map(0x32, MINECRAFT_1_19_4, true),
        map(0x33, MINECRAFT_1_20_2, true));
+      clientbound.register(DefaultSpawnPosition.class, DefaultSpawnPosition::new,
+        map(0x05, MINECRAFT_1_7_2, true),
+        map(0x43, MINECRAFT_1_9, true),
+        map(0x45, MINECRAFT_1_12, true),
+        map(0x46, MINECRAFT_1_12_1, true),
+        map(0x49, MINECRAFT_1_13, true),
+        map(0x4D, MINECRAFT_1_14, true),
+        map(0x4E, MINECRAFT_1_15, true),
+        map(0x42, MINECRAFT_1_16, true),
+        map(0x4B, MINECRAFT_1_17, true),
+        map(0x4A, MINECRAFT_1_19, true),
+        map(0x4D, MINECRAFT_1_19_1, true),
+        map(0x4C, MINECRAFT_1_19_3, true),
+        map(0x50, MINECRAFT_1_19_4, true),
+        map(0x52, MINECRAFT_1_20_2, true),
+        map(0x54, MINECRAFT_1_20_3, true));
+      clientbound.register(MapData.class, MapData::new,
+        map(0x34, MINECRAFT_1_7_2, true),
+        map(0x24, MINECRAFT_1_9, true),
+        map(0x26, MINECRAFT_1_13, true),
+        map(0x27, MINECRAFT_1_15, true),
+        map(0x26, MINECRAFT_1_16, true),
+        map(0x25, MINECRAFT_1_16_2, true),
+        map(0x27, MINECRAFT_1_17, true),
+        map(0x24, MINECRAFT_1_19, true),
+        map(0x26, MINECRAFT_1_19_1, true),
+        map(0x25, MINECRAFT_1_19_3, true),
+        map(0x29, MINECRAFT_1_19_4, true),
+        map(0x2A, MINECRAFT_1_20_2, true));
+      clientbound.register(SetSlot.class, SetSlot::new,
+        map(0x2F, MINECRAFT_1_7_2, true),
+        map(0x16, MINECRAFT_1_9, true),
+        map(0x17, MINECRAFT_1_13, true),
+        map(0x16, MINECRAFT_1_14, true),
+        map(0x17, MINECRAFT_1_15, true),
+        map(0x16, MINECRAFT_1_16, true),
+        map(0x15, MINECRAFT_1_16_2, true),
+        map(0x16, MINECRAFT_1_17, true),
+        map(0x13, MINECRAFT_1_19, true),
+        map(0x12, MINECRAFT_1_19_3, true),
+        map(0x14, MINECRAFT_1_19_4, true),
+        map(0x15, MINECRAFT_1_20_2, true));
      clientbound.register(Chat.class, Chat::new,
-        map(0x02, MINECRAFT_1_7_2, true),
-        map(0x0F, MINECRAFT_1_9, true),
-        map(0x0E, MINECRAFT_1_13, true),
-        map(0x0F, MINECRAFT_1_15, true),
-        map(0x0E, MINECRAFT_1_16, true),
-        map(0x0F, MINECRAFT_1_18_2, true),
-        map(0x5F, MINECRAFT_1_19, true),
-        map(0x62, MINECRAFT_1_19_1, true),
-        map(0x60, MINECRAFT_1_19_3, true),
-        map(0x64, MINECRAFT_1_19_4, true),
-        map(0x67, MINECRAFT_1_20_2, true));
+        map(0x02, MINECRAFT_1_7_2, false),
+        map(0x0F, MINECRAFT_1_9, false),
+        map(0x0E, MINECRAFT_1_13, false),
+        map(0x0F, MINECRAFT_1_15, false),
+        map(0x0E, MINECRAFT_1_16, false),
+        map(0x0F, MINECRAFT_1_17, false),
+        map(0x5F, MINECRAFT_1_19, false),
+        map(0x62, MINECRAFT_1_19_1, false),
+        map(0x60, MINECRAFT_1_19_3, false),
+        map(0x64, MINECRAFT_1_19_4, false),
+        map(0x67, MINECRAFT_1_20_2, false),
+        map(0x69, MINECRAFT_1_20_2, false));
+      clientbound.register(GameEvent.class, GameEvent::new,
+        map(0x20, MINECRAFT_1_20_3, true));

+      serverbound.register(Chat.class, Chat::new,
+        map(0x01, MINECRAFT_1_7_2, false),
+        map(0x02, MINECRAFT_1_9, false),
+        map(0x03, MINECRAFT_1_12, false),
+        map(0x02, MINECRAFT_1_12_1, false),
+        map(0x03, MINECRAFT_1_14, false),
+        map(0x04, MINECRAFT_1_19, false),
+        map(0x05, MINECRAFT_1_19_1, false),
+        map(0x05, MINECRAFT_1_19_3, false));
      serverbound.register(KeepAlive.class, KeepAlive::new,
        map(0x00, MINECRAFT_1_7_2, false),
        map(0x0B, MINECRAFT_1_9, false),
@@ -206,7 +261,8 @@ public enum FallbackPacketRegistry {
        map(0x12, MINECRAFT_1_19_1, false),
        map(0x11, MINECRAFT_1_19_3, false),
        map(0x12, MINECRAFT_1_19_4, false),
-        map(0x14, MINECRAFT_1_20_2, false));
+        map(0x14, MINECRAFT_1_20_2, false),
+        map(0x15, MINECRAFT_1_20_3, false));
      serverbound.register(ClientSettings.class, ClientSettings::new,
        map(0x15, MINECRAFT_1_7_2, false),
        map(0x04, MINECRAFT_1_9, false),
@@ -244,7 +300,8 @@ public enum FallbackPacketRegistry {
        map(0x15, MINECRAFT_1_19_1, false),
        map(0x14, MINECRAFT_1_19_3, false),
        map(0x15, MINECRAFT_1_19_4, false),
-        map(0x17, MINECRAFT_1_20_2, false));
+        map(0x17, MINECRAFT_1_20_2, false),
+        map(0x18, MINECRAFT_1_20_3, false));
      serverbound.register(TeleportConfirm.class, TeleportConfirm::new,
        map(0x00, MINECRAFT_1_9, false));
      serverbound.register(Position.class, Position::new,
@@ -260,7 +317,8 @@ public enum FallbackPacketRegistry {
        map(0x14, MINECRAFT_1_19_1, false),
        map(0x13, MINECRAFT_1_19_3, false),
        map(0x14, MINECRAFT_1_19_4, false),
-        map(0x16, MINECRAFT_1_20_2, false));
+        map(0x16, MINECRAFT_1_20_2, false),
+        map(0x17, MINECRAFT_1_20_3, false));
      serverbound.register(Player.class, Player::new,
        map(0x03, MINECRAFT_1_7_2, false),
        map(0x0F, MINECRAFT_1_9, false),
@@ -274,7 +332,8 @@ public enum FallbackPacketRegistry {
        map(0x17, MINECRAFT_1_19_1, false),
        map(0x16, MINECRAFT_1_19_3, false),
        map(0x17, MINECRAFT_1_19_4, false),
-        map(0x19, MINECRAFT_1_20_2, false));
+        map(0x19, MINECRAFT_1_20_2, false),
+        map(0x1A, MINECRAFT_1_20_3, false));
      serverbound.register(Transaction.class, Transaction::new,
        map(0x0F, MINECRAFT_1_7_2, false),
        map(0x05, MINECRAFT_1_9, false),
@@ -287,7 +346,8 @@ public enum FallbackPacketRegistry {
        map(0x20, MINECRAFT_1_19_1, false),
        map(0x1F, MINECRAFT_1_19_3, false),
        map(0x20, MINECRAFT_1_19_4, false),
-        map(0x23, MINECRAFT_1_20_2, false));
+        map(0x23, MINECRAFT_1_20_2, false),
+        map(0x24, MINECRAFT_1_20_3, false));
    }
  };

@@ -308,14 +368,13 @@ public enum FallbackPacketRegistry {
    private final Map<ProtocolVersion, ProtocolRegistry> versions;

    PacketRegistry() {
-      Map<ProtocolVersion, ProtocolRegistry> mutableVersions = new EnumMap<>(ProtocolVersion.class);
-      for (ProtocolVersion version : ProtocolVersion.values()) {
+      final Map<ProtocolVersion, ProtocolRegistry> mutableVersions = new EnumMap<>(ProtocolVersion.class);
+      for (final ProtocolVersion version : ProtocolVersion.values()) {
        if (!version.isLegacy() && !version.isUnknown()) {
          mutableVersions.put(version, new ProtocolRegistry(version));
        }
      }
-
-      versions = Collections.unmodifiableMap(mutableVersions);
+      this.versions = Collections.unmodifiableMap(mutableVersions);
    }

    ProtocolRegistry getProtocolRegistry(final ProtocolVersion version) {
@@ -345,7 +404,7 @@ public enum FallbackPacketRegistry {
            break;
          }

-          final ProtocolRegistry registry = this.versions.get(protocol);
+          final ProtocolRegistry registry = versions.get(protocol);
          if (registry == null) {
            throw new IllegalArgumentException("Unknown protocol version "
              + current.protocolVersion);
@@ -374,14 +433,7 @@ public enum FallbackPacketRegistry {
    private static ProtocolVersion getProtocolVersion(final @NotNull PacketMapping current,
                                                      final @NotNull PacketMapping next,
                                                      final @NotNull ProtocolVersion from) {
-      final ProtocolVersion last = (ProtocolVersion) SUPPORTED_VERSIONS.toArray()[SUPPORTED_VERSIONS.size() - 1];
-      final ProtocolVersion to = current == next ? last : next.protocolVersion;
-
-      if (from.compareTo(to) >= 0 && from != last) {
-        throw new IllegalArgumentException(String.format(
-          "Next mapping version (%s) should be lower then current (%s)", to, from));
-      }
-      return to;
+      return current == next ? LATEST_VERSION : next.protocolVersion;
    }
  }

@@ -19,31 +19,41 @@ package xyz.jonesdev.sonar.common.fallback.protocol;

 import lombok.experimental.UtilityClass;
 import xyz.jonesdev.sonar.api.Sonar;
+import xyz.jonesdev.sonar.api.timer.SystemTimer;
 import xyz.jonesdev.sonar.common.fallback.protocol.block.BlockPosition;
 import xyz.jonesdev.sonar.common.fallback.protocol.block.BlockType;
 import xyz.jonesdev.sonar.common.fallback.protocol.block.ChangedBlock;
+import xyz.jonesdev.sonar.common.fallback.protocol.map.MapInfoPreparer;
 import xyz.jonesdev.sonar.common.fallback.protocol.packets.config.FinishConfiguration;
-import xyz.jonesdev.sonar.common.fallback.protocol.packets.config.RegistrySync;
-import xyz.jonesdev.sonar.common.fallback.protocol.packets.play.Abilities;
-import xyz.jonesdev.sonar.common.fallback.protocol.packets.play.EmptyChunkData;
-import xyz.jonesdev.sonar.common.fallback.protocol.packets.play.JoinGame;
-import xyz.jonesdev.sonar.common.fallback.protocol.packets.play.UpdateSectionBlocks;
+import xyz.jonesdev.sonar.common.fallback.protocol.packets.config.RegistryData;
+import xyz.jonesdev.sonar.common.fallback.protocol.packets.play.*;

@UtilityClass
 public class FallbackPreparer {

  // Abilities
-  public final FallbackPacket DEFAULT_ABILITIES = new Abilities((byte) 0, 0f, 0f);
+  public final FallbackPacket DEFAULT_ABILITIES = new Abilities(0x00, 0f, 0f);
+  public final FallbackPacket CAPTCHA_ABILITIES = new Abilities(0x02, 0f, 0f);
  // Chunks
  public final FallbackPacket EMPTY_CHUNK_DATA = new EmptyChunkData(0, 0);
  // Finish Configuration
  public final FallbackPacket FINISH_CONFIGURATION = new FinishConfiguration();
  // Synchronize Registry
-  public final FallbackPacket REGISTRY_SYNC = new RegistrySync();
+  public final FallbackPacket REGISTRY_SYNC = new RegistryData();
+  // Keep Alive
+  public final FallbackPacket CAPTCHA_KEEP_ALIVE = new KeepAlive(0L);
+  // Game Event (1.20.3+)
+  public final FallbackPacket START_WRITING_CHUNKS = new GameEvent(13, 0);
+  // Chat
+  public FallbackPacket enterCodeMessage;
+  public FallbackPacket youAreBeingChecked;
+  public FallbackPacket incorrectCaptcha;
  // JoinGame
  public FallbackPacket joinGame;
  // Update Section Blocks
  public FallbackPacket updateSectionBlocks;
+  // Default Spawn Position
+  public FallbackPacket dynamicSpawnPosition;

  // Collisions
  public final int BLOCKS_PER_ROW = 8; // 8 * 8 = 64 (protocol maximum)
@@ -51,6 +61,13 @@ public class FallbackPreparer {
  public final int SPAWN_Z_POSITION = 16 / 2; // middle of the chunk
  public final int DEFAULT_Y_COLLIDE_POSITION = 255; // 255 is the maximum Y position allowed

+  // Captcha position
+  public final FallbackPacket CAPTCHA_POSITION = new PositionLook(
+    SPAWN_X_POSITION, 1337, SPAWN_Z_POSITION, 0f, 90f, 0, false);
+  public final FallbackPacket CAPTCHA_SPAWN_POSITION = new DefaultSpawnPosition(
+    SPAWN_X_POSITION, 1337, SPAWN_Z_POSITION);
+
+  // Blocks
  private final ChangedBlock[] CHANGED_BLOCKS = new ChangedBlock[BLOCKS_PER_ROW * BLOCKS_PER_ROW];

  public int maxMovementTick, dynamicSpawnYPosition;
@@ -58,8 +75,8 @@ public class FallbackPreparer {
  public double maxFallDistance;

  public void prepare() {
-    joinGame = new JoinGame(5,
-      Sonar.get().getConfig().getVerification().getGamemode().getId(),
+    joinGame = new JoinGame(0,
+      Sonar.get().getConfig().getVerification().getGravity().getGamemode().getId(),
      0,
      false,
      0,
@@ -70,7 +87,7 @@ public class FallbackPreparer {
      "minecraft:overworld");

    maxFallDistance = 0;
-    maxMovementTick = Sonar.get().getConfig().getVerification().getMaxMovementTicks();
+    maxMovementTick = Sonar.get().getConfig().getVerification().getGravity().getMaxMovementTicks();
    preparedCachedYMotions = new double[maxMovementTick + 8];

    for (int i = 0; i < preparedCachedYMotions.length; i++) {
@@ -81,6 +98,7 @@ public class FallbackPreparer {

    // Set the dynamic block and collide Y position based on the maximum fall distance
    dynamicSpawnYPosition = DEFAULT_Y_COLLIDE_POSITION + (int) Math.ceil(maxFallDistance);
+    dynamicSpawnPosition = new DefaultSpawnPosition(SPAWN_X_POSITION, dynamicSpawnYPosition, SPAWN_Z_POSITION);

    // Prepare collision platform positions
    int index = 0;
@@ -90,13 +108,28 @@ public class FallbackPreparer {
          x + (BLOCKS_PER_ROW / 2),
          DEFAULT_Y_COLLIDE_POSITION,
          z + (BLOCKS_PER_ROW / 2),
-          0, 0
-        );
+          0, 0);
        CHANGED_BLOCKS[index++] = new ChangedBlock(position, BlockType.BARRIER);
      }
    }

    // Prepare UpdateSectionBlocks packet
    updateSectionBlocks = new UpdateSectionBlocks(0, 0, CHANGED_BLOCKS);
+
+    // "You are being checked" message
+    if (Sonar.get().getConfig().getVerification().getGravity().isEnabled()) {
+      youAreBeingChecked = new Chat(Sonar.get().getConfig().getVerification().getGravity().getYouAreBeingChecked());
+    }
+
+    if (Sonar.get().getConfig().getVerification().getMap().isEnabled()) {
+      enterCodeMessage = new Chat(Sonar.get().getConfig().getVerification().getMap().getEnterCode());
+      incorrectCaptcha = new Chat(Sonar.get().getConfig().getVerification().getMap().getFailedCaptcha());
+
+      final SystemTimer timer = new SystemTimer();
+      Sonar.get().getLogger().info("Precomputing map captcha answers...");
+      // Precompute captcha answers
+      MapInfoPreparer.prepare();
+      Sonar.get().getLogger().info("Successfully precomputed captcha answers in {}s!", timer);
+    }
  }
 }
@@ -28,7 +28,10 @@ import java.util.function.Function;
 public enum BlockType {
  STONE(protocolVersion -> 1),
  BARRIER(protocolVersion -> {
-    // Link: https://github.com/PrismarineJS/minecraft-data/blob/master/data/pc/1.20/blocks.json
+    // Useful resources:
+    // - https://github.com/PrismarineJS/minecraft-data/blob/master/data/pc/
+    // - https://pokechu22.github.io/Burger/1.20.4.html
+    // - https://github.com/ViaVersion/Mappings/tree/main/mappings
    switch (protocolVersion) {
      case MINECRAFT_1_7_2:
      case MINECRAFT_1_7_6:
@@ -73,7 +76,8 @@ public enum BlockType {
      case MINECRAFT_1_20:
        return 10225;
      case MINECRAFT_1_20_2:
-        return 10365;
+      case MINECRAFT_1_20_3:
+        return 10366;
    }
  });

@@ -24,18 +24,15 @@ import org.jetbrains.annotations.NotNull;
 public final class ChangedBlock {
  private final @NotNull BlockPosition position;
  private final BlockType type;
-  private final int legacyChunkPosCrammed;
-  private final int modernChunkPosCrammed;
+  private final int legacyBlockState, blockState;

  public ChangedBlock(final @NotNull BlockPosition position, final BlockType type) {
    this.position = position;
    this.type = type;
-    this.legacyChunkPosCrammed = position.getX()
-      - (position.getChunkX() << 4) << 12 | position.getZ()
-      - (position.getChunkZ() << 4) << 8 | position.getY();
-    this.modernChunkPosCrammed = position.getX()
-      - (position.getChunkX() << 4) << 8 | position.getZ()
-      - (position.getChunkZ() << 4) << 4 | position.getY()
-      - ((position.getY() >> 4) << 4);
+    final int x = position.getX() - (position.getChunkX() << 4);
+    final int y = position.getY();
+    final int z = position.getZ() - (position.getChunkZ() << 4);
+    this.legacyBlockState = x << 12 | z << 8 | y;
+    this.blockState = x << 8 | z << 4 | y - ((y >> 4) << 4);
  }
 }
@@ -0,0 +1,83 @@
+/*
+ * Copyright (C) 2023 Sonar Contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package xyz.jonesdev.sonar.common.fallback.protocol.map;
+
+import lombok.RequiredArgsConstructor;
+import org.jetbrains.annotations.NotNull;
+import xyz.jonesdev.sonar.api.fallback.protocol.ProtocolVersion;
+
+import java.util.function.Function;
+
+@SuppressWarnings("unused")
+@RequiredArgsConstructor
+public enum ItemMapType {
+  FILLED_MAP(protocolVersion -> {
+    // Useful resources:
+    // - https://github.com/PrismarineJS/minecraft-data/blob/master/data/pc/
+    // - https://pokechu22.github.io/Burger/1.20.4.html
+    // - https://github.com/ViaVersion/Mappings/tree/main/mappings
+    switch (protocolVersion) {
+      default:
+        // 1.7-1.12.2
+        return 358;
+      case MINECRAFT_1_13:
+      case MINECRAFT_1_13_1:
+        return 608;
+      case MINECRAFT_1_13_2:
+        return 613;
+      case MINECRAFT_1_14:
+      case MINECRAFT_1_14_1:
+      case MINECRAFT_1_14_2:
+      case MINECRAFT_1_14_3:
+      case MINECRAFT_1_14_4:
+      case MINECRAFT_1_15:
+      case MINECRAFT_1_15_1:
+      case MINECRAFT_1_15_2:
+        return 671;
+      case MINECRAFT_1_16:
+      case MINECRAFT_1_16_1:
+      case MINECRAFT_1_16_2:
+      case MINECRAFT_1_16_3:
+      case MINECRAFT_1_16_4:
+        return 733;
+      case MINECRAFT_1_17:
+      case MINECRAFT_1_17_1:
+      case MINECRAFT_1_18:
+      case MINECRAFT_1_18_2:
+        return 847;
+      case MINECRAFT_1_19:
+      case MINECRAFT_1_19_1:
+        return 886;
+      case MINECRAFT_1_19_3:
+        return 914;
+      case MINECRAFT_1_19_4:
+        return 937;
+      case MINECRAFT_1_20:
+      case MINECRAFT_1_20_2:
+        return 941;
+      case MINECRAFT_1_20_3:
+        return 979;
+    }
+  });
+
+  private final Function<ProtocolVersion, Integer> function;
+
+  public int getId(final @NotNull ProtocolVersion protocolVersion) {
+    return function.apply(protocolVersion);
+  }
+}
@@ -15,12 +15,16 @@
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

-package xyz.jonesdev.sonar.bungee.fallback;
+package xyz.jonesdev.sonar.common.fallback.protocol.map;

-import io.netty.handler.codec.DecoderException;
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;

-final class ConditionFailedException extends DecoderException {
-  public ConditionFailedException(final String message) {
-    super(message);
-  }
+@Getter
+@RequiredArgsConstructor
+public final class MapInfo {
+  private final String answer;
+  private final int columns, rows;
+  private final int x, y;
+  private final byte[] buffer;
 }
@@ -0,0 +1,154 @@
+/*
+ * Copyright (C) 2023 Sonar Contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package xyz.jonesdev.sonar.common.fallback.protocol.map;
+
+import lombok.experimental.UtilityClass;
+import xyz.jonesdev.sonar.api.Sonar;
+
+import java.awt.*;
+import java.awt.image.BufferedImage;
+import java.util.Random;
+
+@UtilityClass
+public class MapInfoPreparer {
+  private final Random RANDOM = new Random();
+
+  private final String[] FONT_TYPES = new String[]{
+    Font.DIALOG_INPUT,
+    Font.DIALOG,
+    Font.SANS_SERIF,
+    Font.SERIF
+  };
+
+  private final int[] FONT_STYLES = new int[]{
+    Font.PLAIN,
+    Font.BOLD,
+    Font.ITALIC,
+    Font.ITALIC | Font.BOLD
+  };
+
+  private final int[][] COLOR_PALETTE = new int[][]{
+    new int[]{ // Blue
+      48,
+      49,
+      50,
+      51
+    },
+    new int[]{ // Black
+      27,
+      45,
+      46,
+      47,
+    },
+    new int[]{ // Green
+      4,
+      28,
+      29,
+      30,
+    },
+    new int[]{ // Red
+      16,
+      17,
+      18,
+      19
+    }
+  };
+
+  private PreparedMapInfo[] cached;
+
+  public void prepare() {
+    cached = new PreparedMapInfo[Sonar.get().getConfig().getVerification().getMap().getPrecomputeAmount()];
+
+    final String dictionary = Sonar.get().getConfig().getVerification().getMap().getDictionary();
+
+    for (int i = 0; i < cached.length; i++) {
+      // Create image
+      final BufferedImage image = new BufferedImage(PreparedMapInfo.DIMENSIONS, PreparedMapInfo.DIMENSIONS,
+        BufferedImage.TYPE_3BYTE_BGR);
+      final Graphics2D graphics = image.createGraphics();
+
+      graphics.setColor(Color.WHITE);
+
+      // Create random font
+      final String fontType = FONT_TYPES[RANDOM.nextInt(FONT_TYPES.length)];
+      final int fontStyle = FONT_STYLES[RANDOM.nextInt(FONT_STYLES.length)];
+      final int fontSize = 30
+        + (Sonar.get().getConfig().getVerification().getMap().isRandomizeFontSize() ? RANDOM.nextInt(11) : 5);
+      @SuppressWarnings("all") final Font answerFont = new Font(fontType, fontStyle, fontSize);
+      graphics.setFont(answerFont);
+
+      // Build answer to the captcha
+      final StringBuilder answerBuilder = new StringBuilder();
+      for (int _i = 0; _i < 4; _i++) {
+        answerBuilder.append(dictionary.charAt(RANDOM.nextInt(dictionary.length())));
+      }
+      final String answer = answerBuilder.toString();
+
+      // Calculate text position
+      final int stringWidth = graphics.getFontMetrics().stringWidth(answer);
+      int _x = image.getWidth() / 2 - stringWidth / 2;
+      int _y = image.getHeight() / 2 + fontSize / 3;
+      int randomOffsetX = 0, randomOffsetY = 3;
+      final int firstPixelX = _x, firstPixelY = _y;
+
+      // Draw each character one by one
+      final FontMetrics fontMetrics = graphics.getFontMetrics();
+      for (final char c : answer.toCharArray()) {
+        if (Sonar.get().getConfig().getVerification().getMap().isRandomizePositions()) {
+          _x += randomOffsetX;
+          _y += randomOffsetY;
+          randomOffsetX = randomOffsetX < 0 ? 1 + RANDOM.nextInt(2) : -1 - RANDOM.nextInt(2);
+          randomOffsetY = randomOffsetY < 0 ? 1 + RANDOM.nextInt(4) : -1 - RANDOM.nextInt(4);
+        }
+
+        final String character = String.valueOf(c);
+        graphics.drawString(character, _x, _y);
+        _x += fontMetrics.stringWidth(character);
+      }
+
+      // Select random color palette
+      final int[] colorPalette = COLOR_PALETTE[i % COLOR_PALETTE.length];
+      // Calculate y and height
+      final int pixelY = firstPixelY - fontSize;
+      final int height = firstPixelY + fontSize / 3;
+      // Store image in buffer
+      final byte[] buffer = new byte[PreparedMapInfo.SCALE];
+      for (int x = firstPixelX; x < _x; x++) {
+        for (int y = pixelY; y < height; y++) {
+          final int index = y * image.getWidth() + x;
+          final int pixel = image.getRGB(x, y);
+          // If the pixel has no color set, set it to white/light gray (if enabled in the config)
+          if (pixel == -16777216) {
+            if (Sonar.get().getConfig().getVerification().getMap().isDrawBackgroundNoise()) {
+              buffer[index] = (byte) (RANDOM.nextInt(100) < 70 ? 14 : 26);
+            }
+            continue;
+          }
+          // Set color of pixel to random color from the palette
+          buffer[index] = (byte) colorPalette[RANDOM.nextInt(colorPalette.length)];
+        }
+      }
+      // Cache buffer to map
+      cached[i] = new PreparedMapInfo(answer, image.getWidth(), image.getHeight(), buffer);
+    }
+  }
+
+  public PreparedMapInfo getRandomCaptcha() {
+    return cached[RANDOM.nextInt(cached.length)];
+  }
+}
@@ -0,0 +1,65 @@
+/*
+ * Copyright (C) 2023 Sonar Contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package xyz.jonesdev.sonar.common.fallback.protocol.map;
+
+import lombok.Getter;
+import org.jetbrains.annotations.NotNull;
+import xyz.jonesdev.sonar.api.fallback.FallbackUser;
+import xyz.jonesdev.sonar.common.fallback.protocol.packets.play.MapData;
+
+import static xyz.jonesdev.sonar.api.fallback.protocol.ProtocolVersion.MINECRAFT_1_8;
+
+@Getter
+public final class PreparedMapInfo {
+  public static final int DIMENSIONS = (int) Math.pow(2, 7);
+  public static final int SCALE = DIMENSIONS * DIMENSIONS;
+
+  private final MapInfo info;
+  private final MapData[] legacy;
+  private final MapData modern;
+
+  public PreparedMapInfo(final String answer,
+                         final int columns, final int rows,
+                         final byte @NotNull [] buffer) {
+    this.info = new MapInfo(answer, columns, rows, 0, 0, buffer);
+
+    // Prepare 1.7 map data using a grid
+    final byte[][] grid = new byte[DIMENSIONS][DIMENSIONS];
+    for (int i = 0; i < buffer.length; i++) {
+      final byte buf = buffer[i];
+      grid[i & Byte.MAX_VALUE][i >> 7] = buf;
+    }
+    this.legacy = new MapData[grid.length];
+    for (int i = 0; i < grid.length; i++) {
+      this.legacy[i] = new MapData(new MapInfo(answer, DIMENSIONS, DIMENSIONS, i, 0, grid[i]));
+    }
+
+    // Prepare 1.8+ map data
+    this.modern = new MapData(info);
+  }
+
+  public void write(final @NotNull FallbackUser<?, ?> user) {
+    if (user.getProtocolVersion().compareTo(MINECRAFT_1_8) < 0) {
+      for (final MapData data : legacy) {
+        user.delayedWrite(data);
+      }
+    } else {
+      user.delayedWrite(modern);
+    }
+  }
+}
@@ -18,33 +18,26 @@
 package xyz.jonesdev.sonar.common.fallback.protocol.packets.config;

 import io.netty.buffer.ByteBuf;
-import io.netty.buffer.ByteBufOutputStream;
-import io.netty.handler.codec.EncoderException;
 import lombok.Getter;
 import lombok.ToString;
-import net.kyori.adventure.nbt.BinaryTagTypes;
 import org.jetbrains.annotations.NotNull;
 import xyz.jonesdev.sonar.api.fallback.protocol.ProtocolVersion;
 import xyz.jonesdev.sonar.common.fallback.protocol.FallbackPacket;
 import xyz.jonesdev.sonar.common.fallback.protocol.dimension.DimensionRegistry;

-import java.io.IOException;
+import static xyz.jonesdev.sonar.common.utility.protocol.ProtocolUtil.writeNamelessCompoundTag;

@Getter
@ToString
-public final class RegistrySync implements FallbackPacket {
+public final class RegistryData implements FallbackPacket {

  @Override
  public void encode(final @NotNull ByteBuf byteBuf, final ProtocolVersion protocolVersion) {
-    try (final ByteBufOutputStream stream = new ByteBufOutputStream(byteBuf)) {
-      stream.writeByte(10); // CompoundTag ID
-      BinaryTagTypes.COMPOUND.write(DimensionRegistry.CODEC_1_20, stream);
-    } catch (IOException exception) {
-      throw new EncoderException("Cannot write NBT CompoundTag");
-    }
+    writeNamelessCompoundTag(byteBuf, DimensionRegistry.CODEC_1_20);
  }

  @Override
  public void decode(final ByteBuf byteBuf, final ProtocolVersion protocolVersion) {
+    throw new UnsupportedOperationException();
  }
 }
@@ -31,7 +31,7 @@ import xyz.jonesdev.sonar.common.fallback.protocol.FallbackPacket;
@NoArgsConstructor
@AllArgsConstructor
 public class Abilities implements FallbackPacket {
-  private byte encodedFlags;
+  private int encodedFlags;
  private float flySpeed, walkSpeed;

  @Override
@@ -17,48 +17,88 @@

 package xyz.jonesdev.sonar.common.fallback.protocol.packets.play;

+import com.google.gson.JsonParser;
 import io.netty.buffer.ByteBuf;
+import io.netty.handler.codec.CorruptedFrameException;
 import lombok.AllArgsConstructor;
-import lombok.Getter;
+import lombok.Data;
 import lombok.NoArgsConstructor;
-import lombok.ToString;
+import net.kyori.adventure.nbt.BinaryTag;
 import net.kyori.adventure.text.Component;
 import net.kyori.adventure.text.serializer.json.JSONComponentSerializer;
 import org.jetbrains.annotations.NotNull;
 import xyz.jonesdev.sonar.api.fallback.protocol.ProtocolVersion;
 import xyz.jonesdev.sonar.common.fallback.protocol.FallbackPacket;

+import java.time.Instant;
 import java.util.UUID;

 import static xyz.jonesdev.sonar.api.fallback.protocol.ProtocolVersion.*;
-import static xyz.jonesdev.sonar.common.utility.protocol.ProtocolUtil.writeString;
-import static xyz.jonesdev.sonar.common.utility.protocol.ProtocolUtil.writeUUID;
+import static xyz.jonesdev.sonar.common.utility.nbt.NBTMessageUtil.fromJson;
+import static xyz.jonesdev.sonar.common.utility.protocol.ProtocolUtil.*;
+import static xyz.jonesdev.sonar.common.utility.protocol.VarIntUtil.readVarInt;
 import static xyz.jonesdev.sonar.common.utility.protocol.VarIntUtil.writeVarInt;

-@Getter
-@ToString
+@Data
@NoArgsConstructor
@AllArgsConstructor
 public final class Chat implements FallbackPacket {
  private static final UUID PLACEHOLDER_UUID = new UUID(0L, 0L);
+  private static final int DIV_FLOOR = -Math.floorDiv(-20, 8);
+
+  public static final byte CHAT_TYPE = (byte) 0;
+  public static final byte SYSTEM_TYPE = (byte) 1;
+  public static final byte GAME_INFO_TYPE = (byte) 2;
+
  private Component component;
-  private byte position;
+  private String message;
+  private byte type;
+  private boolean signedPreview;
+  private boolean unsigned = false;
+  private Instant timestamp;
+  private Instant expiry;
+  private long salt;
+  private boolean signed;
+  private byte[] signature;
+
+  // 1.20.3
+  private BinaryTag nbtMessage;
+
+  // Clientbound LegacyChat
+  public Chat(final Component component) {
+    this(component, SYSTEM_TYPE);
+  }
+
+  // Clientbound LegacyChat
+  public Chat(final Component component, final byte type) {
+    this(component, JSONComponentSerializer.json().serialize(component), type);
+  }
+
+  public Chat(final Component component, final String message, final byte type) {
+    this(component, message, type,
+      false, false, null, null,
+      0L, false, null, fromJson(new JsonParser().parse(message)));
+  }

  @Override
  public void encode(final ByteBuf byteBuf, final @NotNull ProtocolVersion protocolVersion) {
-    final String serialized = JSONComponentSerializer.json().serialize(component);
-    writeString(byteBuf, serialized);
-
-    // Message type
-    if (protocolVersion.compareTo(MINECRAFT_1_19_1) >= 0) {
-      byteBuf.writeBoolean(position == 2);
-    } else if (protocolVersion.compareTo(MINECRAFT_1_19) >= 0) {
-      writeVarInt(byteBuf, position);
+    // Serialized message
+    if (protocolVersion.compareTo(MINECRAFT_1_20_3) >= 0) {
+      writeNamelessCompoundTag(byteBuf, nbtMessage);
    } else {
-      byteBuf.writeByte(this.position);
+      writeString(byteBuf, message);
    }

-    // UUID
+    // Type
+    if (protocolVersion.compareTo(MINECRAFT_1_19_1) >= 0) {
+      byteBuf.writeBoolean(type == GAME_INFO_TYPE);
+    } else if (protocolVersion.compareTo(MINECRAFT_1_19) >= 0) {
+      writeVarInt(byteBuf, type);
+    } else if (protocolVersion.compareTo(MINECRAFT_1_8) >= 0) {
+      byteBuf.writeByte(type);
+    }
+
+    // Sender
    if (protocolVersion.compareTo(MINECRAFT_1_16) >= 0
      && protocolVersion.compareTo(MINECRAFT_1_19) < 0) {
      writeUUID(byteBuf, PLACEHOLDER_UUID);
@@ -66,7 +106,62 @@ public final class Chat implements FallbackPacket {
  }

  @Override
-  public void decode(final ByteBuf byteBuf, final ProtocolVersion protocolVersion) {
-    throw new UnsupportedOperationException();
+  public void decode(final ByteBuf byteBuf, final @NotNull ProtocolVersion protocolVersion) {
+    message = readString(byteBuf, 256);
+
+    if (protocolVersion.compareTo(ProtocolVersion.MINECRAFT_1_19) >= 0) {
+      if (protocolVersion.compareTo(ProtocolVersion.MINECRAFT_1_19_1) <= 0) {
+        final long expiresAt = byteBuf.readLong();
+        final long saltLong = byteBuf.readLong();
+        final byte[] signatureBytes = readByteArray(byteBuf);
+
+        if (saltLong != 0L && signatureBytes.length > 0) {
+          signature = signatureBytes;
+          expiry = Instant.ofEpochMilli(expiresAt);
+        } else if ((protocolVersion.compareTo(ProtocolVersion.MINECRAFT_1_19_1) >= 0
+          || saltLong == 0L) && signatureBytes.length == 0) {
+          unsigned = true;
+        } else {
+          throw new CorruptedFrameException("Invalid signature");
+        }
+
+        signedPreview = byteBuf.readBoolean();
+        if (signedPreview && unsigned) {
+          throw new CorruptedFrameException("Signature missing");
+        }
+
+        if (protocolVersion.compareTo(ProtocolVersion.MINECRAFT_1_19_1) >= 0) {
+          final int size = readVarInt(byteBuf);
+          if (size < 0 || size > 5) {
+            throw new CorruptedFrameException("Invalid previous messages");
+          }
+
+          for (int i = 0; i < size; i++) {
+            readUUID(byteBuf);
+            readByteArray(byteBuf);
+          }
+
+          if (byteBuf.readBoolean()) {
+            readUUID(byteBuf);
+            readByteArray(byteBuf);
+          }
+        }
+      } else {
+        timestamp = Instant.ofEpochMilli(byteBuf.readLong());
+        salt = byteBuf.readLong();
+        signed = byteBuf.readBoolean();
+        if (signed) {
+          byte[] sign = new byte[256];
+          byteBuf.readBytes(sign);
+          signature = sign;
+        } else {
+          signature = new byte[0];
+        }
+
+        readVarInt(byteBuf);
+        byte[] bytes = new byte[DIV_FLOOR];
+        byteBuf.readBytes(bytes);
+      }
+    }
  }
 }
@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) 2023 Sonar Contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package xyz.jonesdev.sonar.common.fallback.protocol.packets.play;
+
+import io.netty.buffer.ByteBuf;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.ToString;
+import org.jetbrains.annotations.NotNull;
+import xyz.jonesdev.sonar.api.fallback.protocol.ProtocolVersion;
+import xyz.jonesdev.sonar.common.fallback.protocol.FallbackPacket;
+
+import static xyz.jonesdev.sonar.api.fallback.protocol.ProtocolVersion.MINECRAFT_1_14;
+import static xyz.jonesdev.sonar.api.fallback.protocol.ProtocolVersion.MINECRAFT_1_17;
+
+@Getter
+@ToString
+@NoArgsConstructor
+@AllArgsConstructor
+public final class DefaultSpawnPosition implements FallbackPacket {
+  private int x, y, z;
+
+  @Override
+  public void encode(final ByteBuf byteBuf, final @NotNull ProtocolVersion protocolVersion) {
+    if (protocolVersion.compareTo(ProtocolVersion.MINECRAFT_1_8) < 0) {
+      byteBuf.writeInt(x);
+      byteBuf.writeInt(y);
+      byteBuf.writeInt(z);
+    } else {
+      final long encoded = protocolVersion.compareTo(MINECRAFT_1_14) < 0
+        ? ((x & 0x3FFFFFFL) << 38) | ((y & 0xFFFL) << 26) | (z & 0x3FFFFFFL)
+        : ((x & 0x3FFFFFFL) << 38) | ((y & 0x3FFFFFFL) << 12) | (z & 0xFFFL);
+
+      byteBuf.writeLong(encoded);
+
+      if (protocolVersion.compareTo(MINECRAFT_1_17) >= 0) {
+        byteBuf.writeFloat(0f);
+      }
+    }
+  }
+
+  @Override
+  public void decode(final ByteBuf byteBuf, final ProtocolVersion protocolVersion) {
+    throw new UnsupportedOperationException();
+  }
+}
@@ -17,11 +17,13 @@

 package xyz.jonesdev.sonar.common.fallback.protocol.packets.play;

+import com.google.gson.JsonParser;
 import io.netty.buffer.ByteBuf;
 import lombok.AllArgsConstructor;
 import lombok.Getter;
 import lombok.NoArgsConstructor;
 import lombok.ToString;
+import net.kyori.adventure.nbt.BinaryTag;
 import net.kyori.adventure.text.Component;
 import net.kyori.adventure.text.serializer.json.JSONComponentSerializer;
 import org.jetbrains.annotations.NotNull;
@@ -29,8 +31,8 @@ import org.jetbrains.annotations.Nullable;
 import xyz.jonesdev.sonar.api.fallback.protocol.ProtocolVersion;
 import xyz.jonesdev.sonar.common.fallback.protocol.FallbackPacket;

-import java.util.Objects;
-
+import static xyz.jonesdev.sonar.common.utility.nbt.NBTMessageUtil.fromJson;
+import static xyz.jonesdev.sonar.common.utility.protocol.ProtocolUtil.writeNamelessCompoundTag;
 import static xyz.jonesdev.sonar.common.utility.protocol.ProtocolUtil.writeString;

@Getter
@@ -39,10 +41,15 @@ import static xyz.jonesdev.sonar.common.utility.protocol.ProtocolUtil.writeStrin
@AllArgsConstructor
 public final class Disconnect implements FallbackPacket {
  private @Nullable String reason;
+  private BinaryTag binaryTag;

  @Override
-  public void encode(final ByteBuf byteBuf, final ProtocolVersion protocolVersion) {
-    writeString(byteBuf, Objects.requireNonNull(reason));
+  public void encode(final ByteBuf byteBuf, final @NotNull ProtocolVersion protocolVersion) {
+    if (protocolVersion.compareTo(ProtocolVersion.MINECRAFT_1_20_3) >= 0) {
+      writeNamelessCompoundTag(byteBuf, binaryTag);
+    } else {
+      writeString(byteBuf, reason);
+    }
  }

  @Override
@@ -51,6 +58,8 @@ public final class Disconnect implements FallbackPacket {
  }

  public static @NotNull Disconnect create(final Component component) {
-    return new Disconnect(JSONComponentSerializer.json().serialize(component));
+    final String serialized = JSONComponentSerializer.json().serialize(component);
+    final BinaryTag binaryTag = fromJson(new JsonParser().parse(serialized));
+    return new Disconnect(serialized, binaryTag);
  }
 }
@@ -29,8 +29,7 @@ import xyz.jonesdev.sonar.api.fallback.protocol.ProtocolVersion;
 import xyz.jonesdev.sonar.common.fallback.protocol.FallbackPacket;

 import static xyz.jonesdev.sonar.api.fallback.protocol.ProtocolVersion.*;
-import static xyz.jonesdev.sonar.common.utility.protocol.ProtocolUtil.writeArray;
-import static xyz.jonesdev.sonar.common.utility.protocol.ProtocolUtil.writeCompoundTag;
+import static xyz.jonesdev.sonar.common.utility.protocol.ProtocolUtil.*;
 import static xyz.jonesdev.sonar.common.utility.protocol.VarIntUtil.writeVarInt;

@Getter
@@ -92,7 +91,11 @@ public final class EmptyChunkData implements FallbackPacket {
    }

    if (protocolVersion.compareTo(MINECRAFT_1_14) >= 0) {
-      writeCompoundTag(byteBuf, protocolVersion.compareTo(MINECRAFT_1_18) < 0 ? LEGACY_TAG : MODERN_TAG);
+      if (protocolVersion.compareTo(MINECRAFT_1_20_2) >= 0) {
+        writeNamelessCompoundTag(byteBuf, MODERN_TAG);
+      } else {
+        writeCompoundTag(byteBuf, protocolVersion.compareTo(MINECRAFT_1_18) < 0 ? LEGACY_TAG : MODERN_TAG);
+      }

      if (protocolVersion.compareTo(MINECRAFT_1_15) >= 0 && protocolVersion.compareTo(MINECRAFT_1_18) < 0) {
        if (protocolVersion.compareTo(MINECRAFT_1_16_2) >= 0) {
@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) 2023 Sonar Contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package xyz.jonesdev.sonar.common.fallback.protocol.packets.play;
+
+import io.netty.buffer.ByteBuf;
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+import org.jetbrains.annotations.NotNull;
+import xyz.jonesdev.sonar.api.fallback.protocol.ProtocolVersion;
+import xyz.jonesdev.sonar.common.fallback.protocol.FallbackPacket;
+
+@Data
+@NoArgsConstructor
+@AllArgsConstructor
+public final class GameEvent implements FallbackPacket {
+  private int type;
+  private float value;
+
+  @Override
+  public void encode(final @NotNull ByteBuf byteBuf, final ProtocolVersion protocolVersion) {
+    byteBuf.writeByte(type);
+    byteBuf.writeFloat(value);
+  }
+
+  @Override
+  public void decode(final ByteBuf byteBuf, final ProtocolVersion protocolVersion) {
+    throw new UnsupportedOperationException();
+  }
+}
@@ -0,0 +1,82 @@
+/*
+ * Copyright (C) 2023 Sonar Contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package xyz.jonesdev.sonar.common.fallback.protocol.packets.play;
+
+import io.netty.buffer.ByteBuf;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.ToString;
+import org.jetbrains.annotations.NotNull;
+import xyz.jonesdev.sonar.api.fallback.protocol.ProtocolVersion;
+import xyz.jonesdev.sonar.common.fallback.protocol.FallbackPacket;
+import xyz.jonesdev.sonar.common.fallback.protocol.map.MapInfo;
+
+import static xyz.jonesdev.sonar.common.utility.protocol.VarIntUtil.writeVarInt;
+
+@Getter
+@ToString
+@NoArgsConstructor
+@AllArgsConstructor
+public final class MapData implements FallbackPacket {
+  private MapInfo mapInfo;
+
+  @Override
+  public void encode(final @NotNull ByteBuf byteBuf, final @NotNull ProtocolVersion protocolVersion) {
+    writeVarInt(byteBuf, 0);
+
+    if (protocolVersion.compareTo(ProtocolVersion.MINECRAFT_1_8) < 0) {
+      byteBuf.writeShort(mapInfo.getBuffer().length + 3);
+      byteBuf.writeByte(0); // scaling
+      byteBuf.writeByte(mapInfo.getX());
+      byteBuf.writeByte(mapInfo.getY());
+
+      byteBuf.writeBytes(mapInfo.getBuffer());
+    } else {
+      byteBuf.writeByte(0); // scaling
+
+      if (protocolVersion.compareTo(ProtocolVersion.MINECRAFT_1_9) >= 0
+        && protocolVersion.compareTo(ProtocolVersion.MINECRAFT_1_17) < 0) {
+        byteBuf.writeBoolean(false);
+      }
+
+      if (protocolVersion.compareTo(ProtocolVersion.MINECRAFT_1_14) >= 0) {
+        byteBuf.writeBoolean(false);
+      }
+
+      if (protocolVersion.compareTo(ProtocolVersion.MINECRAFT_1_17) >= 0) {
+        byteBuf.writeBoolean(false);
+      } else {
+        writeVarInt(byteBuf, 0);
+      }
+
+      byteBuf.writeByte(mapInfo.getColumns());
+      byteBuf.writeByte(mapInfo.getRows());
+      byteBuf.writeByte(mapInfo.getX());
+      byteBuf.writeByte(mapInfo.getY());
+
+      writeVarInt(byteBuf, mapInfo.getBuffer().length);
+      byteBuf.writeBytes(mapInfo.getBuffer());
+    }
+  }
+
+  @Override
+  public void decode(final ByteBuf byteBuf, final ProtocolVersion protocolVersion) {
+    throw new UnsupportedOperationException();
+  }
+}
@@ -0,0 +1,95 @@
+/*
+ * Copyright (C) 2023 Sonar Contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package xyz.jonesdev.sonar.common.fallback.protocol.packets.play;
+
+import io.netty.buffer.ByteBuf;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.ToString;
+import net.kyori.adventure.nbt.CompoundBinaryTag;
+import net.kyori.adventure.nbt.IntBinaryTag;
+import org.jetbrains.annotations.NotNull;
+import xyz.jonesdev.sonar.api.fallback.protocol.ProtocolVersion;
+import xyz.jonesdev.sonar.common.fallback.protocol.FallbackPacket;
+
+import static xyz.jonesdev.sonar.api.fallback.protocol.ProtocolVersion.*;
+import static xyz.jonesdev.sonar.common.utility.protocol.ProtocolUtil.writeCompoundTag;
+import static xyz.jonesdev.sonar.common.utility.protocol.ProtocolUtil.writeNamelessCompoundTag;
+import static xyz.jonesdev.sonar.common.utility.protocol.VarIntUtil.writeVarInt;
+
+@Getter
+@ToString
+@NoArgsConstructor
+@AllArgsConstructor
+public final class SetSlot implements FallbackPacket {
+  private int windowId;
+  private int slot;
+  private int count;
+  private int data;
+  private int itemId;
+  private CompoundBinaryTag compoundBinaryTag;
+
+  public static final CompoundBinaryTag MAP_NBT = CompoundBinaryTag.builder()
+    .put("map", IntBinaryTag.intBinaryTag(0)) // map type
+    .build();
+
+  @Override
+  public void decode(final @NotNull ByteBuf byteBuf, final ProtocolVersion protocolVersion) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public void encode(final @NotNull ByteBuf byteBuf, final @NotNull ProtocolVersion protocolVersion) {
+    byteBuf.writeByte(windowId);
+
+    if (protocolVersion.compareTo(MINECRAFT_1_17_1) >= 0) {
+      writeVarInt(byteBuf, 0);
+    }
+
+    byteBuf.writeShort(slot);
+
+    if (protocolVersion.compareTo(MINECRAFT_1_13_2) >= 0) {
+      byteBuf.writeBoolean(true);
+    }
+
+    if (protocolVersion.compareTo(MINECRAFT_1_13_2) < 0) {
+      byteBuf.writeShort(itemId);
+    } else {
+      writeVarInt(byteBuf, itemId);
+    }
+    byteBuf.writeByte(count);
+    if (protocolVersion.compareTo(MINECRAFT_1_13) < 0) {
+      byteBuf.writeShort(data);
+    }
+
+    if (protocolVersion.compareTo(MINECRAFT_1_17) < 0) {
+      if (protocolVersion.compareTo(ProtocolVersion.MINECRAFT_1_8) < 0) {
+        byteBuf.writeShort(-1);
+      } else {
+        byteBuf.writeByte(0);
+      }
+    } else {
+      if (protocolVersion.compareTo(MINECRAFT_1_20_2) >= 0) {
+        writeNamelessCompoundTag(byteBuf, compoundBinaryTag);
+      } else {
+        writeCompoundTag(byteBuf, compoundBinaryTag);
+      }
+    }
+  }
+}
@@ -53,12 +53,12 @@ public final class UpdateSectionBlocks implements FallbackPacket {
      }

      for (final ChangedBlock block : changedBlocks) {
-        byteBuf.writeShort(block.getLegacyChunkPosCrammed());
-        final int id = block.getType().getId(protocolVersion);
+        byteBuf.writeShort(block.getLegacyBlockState());
+        final int blockId = block.getType().getId(protocolVersion);
        if (protocolVersion.compareTo(MINECRAFT_1_13) >= 0) {
-          writeVarInt(byteBuf, id);
+          writeVarInt(byteBuf, blockId);
        } else {
-          final int shiftedBlockId = id << 4;
+          final int shiftedBlockId = blockId << 4;
          if (protocolVersion.compareTo(MINECRAFT_1_8) < 0) {
            byteBuf.writeShort(shiftedBlockId);
          } else {
@@ -67,8 +67,10 @@ public final class UpdateSectionBlocks implements FallbackPacket {
        }
      }
    } else {
+      // We only need one Y position
      final int sectionY = changedBlocks[0].getPosition().getY() >> 4;

+      // https://wiki.vg/Protocol#Update_Section_Blocks
      byteBuf.writeLong(((sectionX & 0x3FFFFFL) << 42) | (sectionY & 0xFFFFF) | ((sectionZ & 0x3FFFFFL) << 20));

      // 1.20+ don't have light update suppression
@@ -79,8 +81,9 @@ public final class UpdateSectionBlocks implements FallbackPacket {
      writeVarInt(byteBuf, changedBlocks.length);

      for (final ChangedBlock block : changedBlocks) {
+        // https://wiki.vg/Protocol#Update_Section_Blocks
        final int shiftedBlockId = block.getType().getId(protocolVersion) << 12;
-        final long positionIdValue = shiftedBlockId | block.getModernChunkPosCrammed();
+        final long positionIdValue = shiftedBlockId | block.getBlockState();
        writeVarLong(byteBuf, positionIdValue);
      }
    }
@@ -26,7 +26,6 @@ public final class SubcommandRegistryHolder implements SubcommandRegistry {
      new BlacklistCommand(),
      new VerifiedCommand(),
      new StatisticsCommand(),
-      new LockdownCommand(),
      new VerboseCommand(),
      new ReloadCommand(),
      new DumpCommand()
@@ -54,7 +54,7 @@ public final class BlacklistCommand extends Subcommand {
        if (inetAddress == null) return;

        // Make sure the IP is not blacklisted already
-        if (SONAR.getFallback().getBlacklisted().has(inetAddress.toString())) {
+        if (SONAR.getFallback().getBlacklisted().has(inetAddress)) {
          invocation.getSender().sendMessage(SONAR.getConfig().getCommands().getBlacklistDuplicate());
          return;
        }
@@ -66,7 +66,7 @@ public final class BlacklistCommand extends Subcommand {
        }

        // Blacklist the given IP address
-        SONAR.getFallback().getBlacklisted().put(inetAddress.toString());
+        SONAR.getFallback().getBlacklisted().put(inetAddress);
        invocation.getSender().sendMessage(SONAR.getConfig().getCommands().getBlacklistAdd()
          .replace("%ip%", rawInetAddress));
        break;
@@ -85,13 +85,13 @@ public final class BlacklistCommand extends Subcommand {
        if (inetAddress == null) return;

        // Make sure the IP is blacklisted
-        if (!SONAR.getFallback().getBlacklisted().has(inetAddress.toString())) {
+        if (!SONAR.getFallback().getBlacklisted().has(inetAddress)) {
          invocation.getSender().sendMessage(SONAR.getConfig().getCommands().getBlacklistNotFound());
          return;
        }

        // Invalidate the cache entry of the blacklisted IP address
-        SONAR.getFallback().getBlacklisted().invalidate(inetAddress.toString());
+        SONAR.getFallback().getBlacklisted().invalidate(inetAddress);
        invocation.getSender().sendMessage(SONAR.getConfig().getCommands().getBlacklistRemove()
          .replace("%ip%", rawInetAddress));
        break;
@@ -1,41 +0,0 @@
-/*
- * Copyright (C) 2023 Sonar Contributors
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <https://www.gnu.org/licenses/>.
- */
-
-package xyz.jonesdev.sonar.common.subcommand.impl;
-
-import org.jetbrains.annotations.NotNull;
-import xyz.jonesdev.sonar.api.command.CommandInvocation;
-import xyz.jonesdev.sonar.api.command.subcommand.Subcommand;
-import xyz.jonesdev.sonar.api.command.subcommand.SubcommandInfo;
-
-@SubcommandInfo(
-  name = "lockdown",
-  description = "Prevent all players from joining"
-)
-public final class LockdownCommand extends Subcommand {
-
-  @Override
-  protected void execute(final @NotNull CommandInvocation invocation) {
-    final boolean newState = !SONAR.getConfig().getLockdown().isEnabled();
-    SONAR.getConfig().getLockdown().setEnabled(newState);
-    SONAR.getConfig().getGeneralConfig().set("lockdown.enabled", newState);
-    SONAR.getConfig().getGeneralConfig().save();
-
-    invocation.getSender().sendMessage(newState
-      ? SONAR.getConfig().getLockdown().getActivated() : SONAR.getConfig().getLockdown().getDeactivated());
-  }
-}
@@ -1,3 +1,20 @@
+/*
+ * Copyright (C) 2023 Sonar Contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
 package xyz.jonesdev.sonar.common.update;

 import com.google.gson.JsonObject;
@@ -0,0 +1,115 @@
+/*
+ * Copyright (C) 2023 Sonar Contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package xyz.jonesdev.sonar.common.utility.nbt;
+
+import com.google.gson.*;
+import lombok.experimental.UtilityClass;
+import net.kyori.adventure.nbt.*;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+
+// Taken from
+// https://github.com/Nan1t/NanoLimbo/pull/79/files#diff-0e355ffd4eb0e15e2c2e628227debc9b6ccefeb167d7b9619311cdc7db2645ec
+@UtilityClass
+public class NBTMessageUtil {
+  public static BinaryTag fromJson(final JsonElement json) {
+    if (json instanceof JsonPrimitive) {
+      JsonPrimitive jsonPrimitive = (JsonPrimitive) json;
+      if (jsonPrimitive.isNumber()) {
+        Number number = json.getAsNumber();
+
+        if (number instanceof Byte) {
+          return ByteBinaryTag.byteBinaryTag((Byte) number);
+        } else if (number instanceof Short) {
+          return ShortBinaryTag.shortBinaryTag((Short) number);
+        } else if (number instanceof Integer) {
+          return IntBinaryTag.intBinaryTag((Integer) number);
+        } else if (number instanceof Long) {
+          return LongBinaryTag.longBinaryTag((Long) number);
+        } else if (number instanceof Float) {
+          return FloatBinaryTag.floatBinaryTag((Float) number);
+        } else if (number instanceof Double) {
+          return DoubleBinaryTag.doubleBinaryTag((Double) number);
+        }
+      } else if (jsonPrimitive.isString()) {
+        return StringBinaryTag.stringBinaryTag(jsonPrimitive.getAsString());
+      } else if (jsonPrimitive.isBoolean()) {
+        return ByteBinaryTag.byteBinaryTag(jsonPrimitive.getAsBoolean() ? (byte) 1 : (byte) 0);
+      } else {
+        throw new IllegalArgumentException("Unknown JSON primitive: " + jsonPrimitive);
+      }
+    } else if (json instanceof JsonObject) {
+      final CompoundBinaryTag.Builder builder = CompoundBinaryTag.builder();
+      for (Map.Entry<String, JsonElement> property : ((JsonObject) json).entrySet()) {
+        builder.put(property.getKey(), fromJson(property.getValue()));
+      }
+      return builder.build();
+    } else if (json instanceof JsonArray) {
+      final JsonArray jsonArray = ((JsonArray) json);
+
+      if (jsonArray.size() == 0) {
+        return ListBinaryTag.listBinaryTag(EndBinaryTag.endBinaryTag().type(), Collections.emptyList());
+      }
+
+      final BinaryTagType<?> tagByteType = ByteBinaryTag.ZERO.type();
+      final BinaryTagType<?> tagIntType = IntBinaryTag.intBinaryTag(0).type();
+      final BinaryTagType<?> tagLongType = LongBinaryTag.longBinaryTag(0).type();
+
+      final BinaryTag listTag;
+      final BinaryTagType<?> listType = fromJson(jsonArray.get(0)).type();
+
+      if (listType.equals(tagByteType)) {
+        byte[] bytes = new byte[jsonArray.size()];
+        for (int i = 0; i < bytes.length; i++) {
+          bytes[i] = (Byte) jsonArray.get(i).getAsNumber();
+        }
+        listTag = ByteArrayBinaryTag.byteArrayBinaryTag(bytes);
+      } else if (listType.equals(tagIntType)) {
+        int[] ints = new int[jsonArray.size()];
+        for (int i = 0; i < ints.length; i++) {
+          ints[i] = (Integer) jsonArray.get(i).getAsNumber();
+        }
+        listTag = IntArrayBinaryTag.intArrayBinaryTag(ints);
+      } else if (listType.equals(tagLongType)) {
+        long[] longs = new long[jsonArray.size()];
+        for (int i = 0; i < longs.length; i++) {
+          longs[i] = (Long) jsonArray.get(i).getAsNumber();
+        }
+        listTag = LongArrayBinaryTag.longArrayBinaryTag(longs);
+      } else {
+        final List<BinaryTag> tagItems = new ArrayList<>(jsonArray.size());
+
+        for (final JsonElement jsonEl : jsonArray) {
+          final BinaryTag subTag = fromJson(jsonEl);
+          if (subTag.type() != listType) {
+            throw new IllegalArgumentException("Cannot convert mixed JsonArray to Tag");
+          }
+          tagItems.add(subTag);
+        }
+        listTag = ListBinaryTag.listBinaryTag(listType, tagItems);
+      }
+      return listTag;
+    } else if (json instanceof JsonNull) {
+      return EndBinaryTag.endBinaryTag();
+    }
+    throw new IllegalArgumentException("Unknown JSON element: " + json);
+  }
+}
@@ -24,8 +24,7 @@ import io.netty.handler.codec.CorruptedFrameException;
 import io.netty.handler.codec.DecoderException;
 import io.netty.handler.codec.EncoderException;
 import lombok.experimental.UtilityClass;
-import net.kyori.adventure.nbt.BinaryTagIO;
-import net.kyori.adventure.nbt.CompoundBinaryTag;
+import net.kyori.adventure.nbt.*;
 import org.jetbrains.annotations.NotNull;

 import java.io.DataOutput;
@@ -34,6 +33,8 @@ import java.nio.charset.StandardCharsets;
 import java.util.UUID;
 import java.util.regex.Pattern;

+import static xyz.jonesdev.sonar.common.utility.protocol.VarIntUtil.readVarInt;
+
 // Taken from
 // https://github.com/PaperMC/Velocity/blob/dev/3.0.0/proxy/src/main/java/com/velocitypowered/proxy/protocol/ProtocolUtils.java
@UtilityClass
@@ -48,6 +49,24 @@ public class ProtocolUtil {
  private static final String UNREGISTER_CHANNEL = "minecraft:unregister";
  private static final Pattern INVALID_IDENTIFIER_REGEX = Pattern.compile("[^a-z0-9\\-_]*");

+  public static @NotNull UUID readUUID(final @NotNull ByteBuf byteBuf) {
+    return new UUID(byteBuf.readLong(), byteBuf.readLong());
+  }
+
+  public static byte @NotNull [] readByteArray(final ByteBuf byteBuf) {
+    return readByteArray(byteBuf, Short.MAX_VALUE);
+  }
+
+  public static byte @NotNull [] readByteArray(final ByteBuf byteBuf, final int cap) {
+    int length = readVarInt(byteBuf);
+    checkFrame(length >= 0, "Got a negative-length array");
+    checkFrame(length <= cap, "Bad array size");
+    checkFrame(byteBuf.isReadable(length), "Trying to read an array that is too long");
+    byte[] array = new byte[length];
+    byteBuf.readBytes(array);
+    return array;
+  }
+
  public static @NotNull String readBrandMessage(final @NotNull ByteBuf content) throws DecoderException {
    final ByteBuf slice = content.slice();
    try {
@@ -113,7 +132,46 @@ public class ProtocolUtil {
  public static void writeCompoundTag(final ByteBuf byteBuf, final CompoundBinaryTag compoundTag) {
    try {
      BinaryTagIO.writer().write(compoundTag, (DataOutput) new ByteBufOutputStream(byteBuf));
-    } catch (IOException e) {
+    } catch (IOException exception) {
+      throw new EncoderException("Unable to encode NBT CompoundTag");
+    }
+  }
+
+  // Taken from
+  // https://github.com/Nan1t/NanoLimbo/pull/79/files#diff-4aa8208044741102c6326c7e85086e6fa8fcc7c064f7df6fd0411baf5f2b4504
+  public static void writeNamelessCompoundTag(final @NotNull ByteBuf byteBuf, final @NotNull BinaryTag binaryTag) {
+    try (final ByteBufOutputStream output = new ByteBufOutputStream(byteBuf)) {
+      // TODO: Find a way to improve this...
+      output.writeByte(binaryTag.type().id());
+      if (binaryTag instanceof CompoundBinaryTag) {
+        CompoundBinaryTag tag = (CompoundBinaryTag) binaryTag;
+        tag.type().write(tag, output);
+      } else if (binaryTag instanceof ByteBinaryTag) {
+        ByteBinaryTag tag = (ByteBinaryTag) binaryTag;
+        tag.type().write(tag, output);
+      } else if (binaryTag instanceof ShortBinaryTag) {
+        ShortBinaryTag tag = (ShortBinaryTag) binaryTag;
+        tag.type().write(tag, output);
+      } else if (binaryTag instanceof IntBinaryTag) {
+        IntBinaryTag tag = (IntBinaryTag) binaryTag;
+        tag.type().write(tag, output);
+      } else if (binaryTag instanceof LongBinaryTag) {
+        LongBinaryTag tag = (LongBinaryTag) binaryTag;
+        tag.type().write(tag, output);
+      } else if (binaryTag instanceof DoubleBinaryTag) {
+        DoubleBinaryTag tag = (DoubleBinaryTag) binaryTag;
+        tag.type().write(tag, output);
+      } else if (binaryTag instanceof StringBinaryTag) {
+        StringBinaryTag tag = (StringBinaryTag) binaryTag;
+        tag.type().write(tag, output);
+      } else if (binaryTag instanceof ListBinaryTag) {
+        ListBinaryTag tag = (ListBinaryTag) binaryTag;
+        tag.type().write(tag, output);
+      } else if (binaryTag instanceof EndBinaryTag) {
+        EndBinaryTag tag = (EndBinaryTag) binaryTag;
+        tag.type().write(tag, output);
+      }
+    } catch (IOException exception) {
      throw new EncoderException("Unable to encode NBT CompoundTag");
    }
  }
@@ -20,7 +20,6 @@ package xyz.jonesdev.sonar.velocity.fallback;
 import com.velocitypowered.api.event.PostOrder;
 import com.velocitypowered.api.event.Subscribe;
 import com.velocitypowered.api.event.connection.LoginEvent;
-import com.velocitypowered.api.event.connection.PostLoginEvent;
 import com.velocitypowered.api.event.connection.PreLoginEvent;
 import com.velocitypowered.api.proxy.crypto.IdentifiedKey;
 import com.velocitypowered.api.util.GameProfile;
@@ -36,8 +35,6 @@ import io.netty.channel.Channel;
 import io.netty.channel.ChannelPipeline;
 import lombok.RequiredArgsConstructor;
 import lombok.val;
-import net.kyori.adventure.text.Component;
-import net.kyori.adventure.text.minimessage.MiniMessage;
 import org.jetbrains.annotations.NotNull;
 import xyz.jonesdev.sonar.api.ReflectiveOperationException;
 import xyz.jonesdev.sonar.api.Sonar;
@@ -155,7 +152,8 @@ public final class FallbackListener {
        val activeSessionHandler = (MinecraftSessionHandler) SESSION_HANDLER_FIELD.get(mcConnection);

        // Check the blacklist here since we cannot let the player "ghost join"
-        if (fallback.getBlacklisted().has(inetAddress.toString())) {
+        if (fallback.getBlacklisted().has(inetAddress)) {
+          // Mark the connection as dead to avoid unnecessary console logs
          markConnectionAsDead(activeSessionHandler);
          initialConnection.getConnection().closeWith(Disconnect.create(
            Sonar.get().getConfig().getVerification().getBlacklisted(),
@@ -167,17 +165,32 @@ public final class FallbackListener {
        // Don't continue the verification process if the verification is disabled
        if (!Sonar.get().getFallback().shouldVerifyNewPlayers()) return;

+        // Completely skip Geyser connections
+        if (isGeyserConnection(channel)) {
+          fallback.getLogger().info("Skipping Geyser player: {}{}",
+            event.getUsername(), Sonar.get().getConfig().formatAddress(inetAddress));
+          return;
+        }
+
+        // Check if the protocol ID of the player is not allowed to enter the server
+        final int protocolId = inboundConnection.getProtocolVersion().getProtocol();
+        if (Sonar.get().getConfig().getVerification().getBlacklistedProtocols().contains(protocolId)) {
+          // Mark the connection as dead to avoid unnecessary console logs
+          markConnectionAsDead(activeSessionHandler);
+          initialConnection.getConnection().closeWith(Disconnect.create(
+            Sonar.get().getConfig().getVerification().getProtocolBlacklisted(),
+            inboundConnection.getProtocolVersion()
+          ));
+          return;
+        }
+
        // Check if the player is already verified.
        // No one wants to be verified over and over again.
        final GameProfile gameProfile = GameProfile.forOfflinePlayer(event.getUsername());
        if (Sonar.get().getVerifiedPlayerController().has(inetAddress, gameProfile.getId())) return;

-        // Completely skip Geyser connections
-        if (isGeyserConnection(channel)) {
-          fallback.getLogger().info("Skipping Geyser player: {}{}",
-            gameProfile.getName(), Sonar.get().getConfig().formatAddress(inetAddress));
-          return;
-        }
+        // Check if the protocol ID of the player is allowed to bypass verification
+        if (Sonar.get().getConfig().getVerification().getWhitelistedProtocols().contains(protocolId)) return;

        // We now mark the connection as dead by using our fake connection
        markConnectionAsDead(activeSessionHandler);
@@ -204,16 +217,6 @@ public final class FallbackListener {
          return;
        }

-        // We cannot allow too many players on our Fallback server
-        // There's technically no reason for limiting this, but we'll better stay safe.
-        if (fallback.getConnected().size() > Sonar.get().getConfig().getVerification().getMaxVerifyingPlayers()) {
-          initialConnection.getConnection().closeWith(Disconnect.create(
-            Sonar.get().getConfig().getVerification().getTooManyPlayers(),
-            inboundConnection.getProtocolVersion()
-          ));
-          return;
-        }
-
        // Check if the IP address is currently being rate-limited
        if (!fallback.getRatelimiter().attempt(inetAddress)) {
          initialConnection.getConnection().closeWith(Disconnect.create(
@@ -243,12 +246,8 @@ public final class FallbackListener {

          // Add better timeout handler to avoid known exploits or issues
          // We also want to timeout bots quickly to avoid flooding
-          pipeline.replace(
-            READ_TIMEOUT,
-            READ_TIMEOUT,
-            new FallbackTimeoutHandler(Sonar.get().getConfig().getVerification().getReadTimeout(),
-              TimeUnit.MILLISECONDS)
-          );
+          final int readTimeout = Sonar.get().getConfig().getVerification().getReadTimeout();
+          pipeline.replace(READ_TIMEOUT, READ_TIMEOUT, new FallbackTimeoutHandler(readTimeout, TimeUnit.MILLISECONDS));

          // We need to determine if the player is premium before we handle the connection,
          // so we can create a ConnectedPlayer instance without having to spoof this
@@ -278,7 +277,7 @@ public final class FallbackListener {
          final FallbackUserWrapper user = new FallbackUserWrapper(
            fallback, connectedPlayer, mcConnection, mcConnection.getChannel(),
            mcConnection.getChannel().pipeline(), inetAddress,
-            ProtocolVersion.fromId(connectedPlayer.getProtocolVersion().getProtocol())
+            ProtocolVersion.fromId(protocolId)
          );

          // Disconnect if the protocol version could not be resolved
@@ -334,10 +333,8 @@ public final class FallbackListener {
            ? FallbackPacketRegistry.CONFIG : FallbackPacketRegistry.GAME);

          // Replace normal decoder to allow custom packets
-          user.getPipeline().replace(
-            MINECRAFT_DECODER, FALLBACK_PACKET_DECODER, new FallbackPacketDecoder(user,
-              new FallbackVerificationHandler(user, gameProfile.getName(), connectedPlayer.getUniqueId())
-            ));
+          user.getPipeline().replace(MINECRAFT_DECODER, FALLBACK_PACKET_DECODER, new FallbackPacketDecoder(user,
+            new FallbackVerificationHandler(user, gameProfile.getName(), connectedPlayer.getUniqueId())));
        }));
      } catch (Throwable throwable) {
        throw new ReflectiveOperationException(throwable);
@@ -349,22 +346,6 @@ public final class FallbackListener {
  public void handle(final @NotNull LoginEvent event) {
    val connectedPlayer = (ConnectedPlayer) event.getPlayer();

-    if (Sonar.get().getConfig().getLockdown().isEnabled()
-      && !event.getPlayer().hasPermission(Sonar.get().getConfig().getLockdown().getBypassPermission())) {
-      connectedPlayer.getConnection().closeWith(Disconnect.create(
-        Sonar.get().getConfig().getLockdown().getDisconnect(), connectedPlayer.getProtocolVersion()));
-
-      if (Sonar.get().getConfig().getLockdown().isLogAttempts()) {
-        Sonar.get().getLogger().info(Sonar.get().getConfig().getLockdown().getConsoleLog()
-          .replace("%player%", event.getPlayer().getUsername())
-          .replace("%ip%", Sonar.get().getConfig()
-            .formatAddress(event.getPlayer().getRemoteAddress().getAddress()))
-          .replace("%protocol%",
-            String.valueOf(event.getPlayer().getProtocolVersion().getProtocol())));
-      }
-      return;
-    }
-
    final InetAddress inetAddress = event.getPlayer().getRemoteAddress().getAddress();

    // Check if the number of online players using the same IP address as
@@ -384,15 +365,4 @@ public final class FallbackListener {
      }
    }
  }
-
-  @Subscribe(order = PostOrder.LAST)
-  public void handle(final @NotNull PostLoginEvent event) {
-    if (Sonar.get().getConfig().getLockdown().isEnabled() && Sonar.get().getConfig().getLockdown().isNotifyAdmins()) {
-      if (event.getPlayer().hasPermission(Sonar.get().getConfig().getLockdown().getBypassPermission())) {
-        final String notification = Sonar.get().getConfig().getLockdown().getNotification();
-        final Component deserialized = MiniMessage.miniMessage().deserialize(notification);
-        event.getPlayer().sendMessage(deserialized);
-      }
-    }
-  }
 }
Author	SHA1	Message	Date
Jones	e9c212b9e4	Release 2.0.10 (#126 )	2023-12-15 16:02:44 +01:00
Jones	42da141f2b	Remove lockdown mode (#125 ) * https://discord.com/channels/923308209769426994/1180500530896842832	2023-12-15 15:49:50 +01:00
Jones	e0bc83f8ef	Implement Minecraft 1.20.4 support (#124 ) * feat: implement GameEvent packet * fix: make Chat & Disconnect packet work on 1.20.3+ * fix: don't send ChunkData twice * fix: invalid serverbound PositionLook packet id on 1.20.3+ * fix: remove custom read-timeout value * fix: trigger channel read after Fallback packet decode * fix: only expect 10 unique kick packets instead of 16 * fix: map item id mapping * feat: 1.20.3 barrier block mappings	2023-12-15 15:44:14 +01:00
Jones	59822ef541	Optimize in-class performance during verification (#123 ) * style: use Getter for the entire class instead of a single field * style: reformat code using IntelliSense * fix: optimize IP address connection ratelimiter	2023-12-07 21:16:20 +01:00
Jones	38fbfff896	Fix README badge line separator not displaying (#122 )	2023-12-07 21:00:18 +01:00
Jones	6725975cf1	Add CodeFactor rating to README (#121 ) * feat: add 1.20.3 protocol version to allowed protocols * feat: update packet ids for 1.20.3 * chore: add code factor rating to README	2023-12-07 20:57:41 +01:00
Jones	d59fd4b431	Avoid using custom exceptions in the decoder (#119 )	2023-12-04 16:48:28 +01:00
Jones	a76ca2f91d	Add optional map captcha check to verification (#118 ) * feat: change field type "encodedFlags" of Abilities packet to int * feat: add MapData packet feat: add SetSlot packet * feat: implement map captcha state * feat: [wip] implement simple map captcha * feat: cache captcha spawn position packet * feat: add a chat message when you verify and enter the captcha * fix: Chat packet error on 1.7 * feat: make map prepared amount and dictionary customizable * fix: SetSlot packet error on 1.7 * fix: make map data work on 1.7 * feat: randomize font size & font style * fix: implement KeepAlive during captcha and add timer * feat: add color and x/y randomization to map captcha * feat: add green and red color palette * feat: implement captcha validation * fix: chat packet not working on 1.7-1.18.2 * fix: only draw important used pixels * feat: optimize color palette * feat: set map image dimensions to 86x86 * feat: set background color of image to white/light gray * feat: recode map info preparing and map data packet sending * fix: x/y offset for 1.8+ in map info * fix: add prefix to translated messages for the map captcha * feat: make some map captcha options changeable * fix: set the default font size to the average (instead of max) * fix: Chat packet not working on 1.17-1.18.1 * fix: only send DefaultSpawnPosition to >=1.18.2 clients * fix: return if captcha is correct to prevent further code execution * feat: cache dynamic DefaultSpawnPosition packet	2023-12-02 14:13:30 +01:00
Jones	30803ba6e4	Fix permanent "Loading terrain" screen on 1.18.2+ (#117 ) * feat: remove unused Chat packet * feat: set JoinGame entityId to 0 * fix: add DefaultSpawnPosition to fix "Loading terrain" screen * fix: 1.20.2 barrier block state id	2023-11-28 17:30:12 +01:00
Jones	194232804b	Remove unnecessary metadata in the compilation process (#116 ) * build: exclude unnecessary version information * build: remove unnecessary file timestamps	2023-11-25 16:48:28 +01:00
Jones	19c97b26b6	Relocate some packages of net.kyori (#115 ) * build(deps): relocate cappuccino * build(deps): relocate net.kyori (except for text and audience)	2023-11-25 16:23:31 +01:00
Jones	d66719b3e0	Fix state checks in verification not being handled properly (#114 )	2023-11-24 21:06:19 +01:00
Michel Elkenwaat	9226908002	style: add copyright header to UpdateChecker.java	2023-11-24 19:37:35 +01:00
Jones	ac74f14dc0	Make RegistrySync packet use the implemented nbt writing method (#112 )	2023-11-23 17:54:53 +01:00
Michel Elkenwaat	8f11a53b38	fix: use ByteBufOutputStream in an AutoClosable statement	2023-11-23 17:54:21 +01:00
Jones	0b4394624f	Release 2.0.9 (#111 )	2023-11-22 15:56:26 +01:00
Michel Elkenwaat	d8f7e288e8	build(deps): bump gradle from 8.3 to 8.4	2023-11-21 18:18:35 +01:00
Jones	3f3411ca9d	Implement nameless compound tag for 1.20.2+ chunks (#110 )	2023-11-21 17:41:59 +01:00
Jones	14ae85384a	Optimize verification by using different data types (#109 ) * fix: optimize ConcurrentHashMap usage in Fallback * feat: remove max-verifying-players option from config * fix: use hashset for whitelist and blacklisted protocol ids * fix: yaml configuration formatting error on empty collections	2023-11-16 16:58:30 +01:00
Jones	8204477eb6	Implement protocol version whitelist and blacklist (#108 ) * feat: allow certain protocol Ids to be exempt from verification * fix(bungee): run blacklist check even if verification is disabled * fix: run Geyser check before creating a new GameProfile * feat: the blacklist should cache the InetAddress and not a String * fix: support IPv6 (and more) in all subcommand arguments * feat: add blacklisted protocol versions	2023-11-16 16:39:35 +01:00
Jones	44754e5027	Use correct values for webhook attack statistics (#107 )	2023-11-14 12:01:05 +01:00
dependabot[bot]	847936ed08	Bump io.netty:netty-all from 4.1.100.Final to 4.1.101.Final (#105 ) Bumps [io.netty:netty-all](https://github.com/netty/netty) from 4.1.100.Final to 4.1.101.Final. - [Commits](https://github.com/netty/netty/compare/netty-4.1.100.Final...netty-4.1.101.Final) --- updated-dependencies: - dependency-name: io.netty:netty-all dependency-type: direct:production update-type: version-update:semver-patch ... Signed-off-by: dependabot[bot] <support@github.com> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>	2023-11-13 14:06:47 +01:00