PaperMC/paper-server/patches/features/0007-Anti-Xray.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: stonar96 <minecraft.stonar96@gmail.com>
Date: Thu, 25 Nov 2021 13:27:51 +0100
Subject: [PATCH] Anti-Xray


diff --git a/io/papermc/paper/FeatureHooks.java b/io/papermc/paper/FeatureHooks.java
index 1e5d94cdcdffb4d2940f17bacdf0e6a488e84318..d3aebc7f833764351c8e5fe1fad1aa2f8718ca37 100644
--- a/io/papermc/paper/FeatureHooks.java
+++ b/io/papermc/paper/FeatureHooks.java
@@ -7,6 +7,7 @@ import it.unimi.dsi.fastutil.longs.LongSets;
 import it.unimi.dsi.fastutil.objects.ObjectOpenHashSet;
 import it.unimi.dsi.fastutil.objects.ObjectSet;
 import it.unimi.dsi.fastutil.objects.ObjectSets;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -36,20 +37,25 @@ public final class FeatureHooks {
     }
 
     public static LevelChunkSection createSection(final Registry<Biome> biomeRegistry, final Level level, final ChunkPos chunkPos, final int chunkSection) {
-        return new LevelChunkSection(biomeRegistry);
+        return new LevelChunkSection(biomeRegistry, level, chunkPos, chunkSection); // Paper - Anti-Xray - Add parameters
     }
 
     public static void sendChunkRefreshPackets(final List<ServerPlayer> playersInRange, final LevelChunk chunk) {
-        final ClientboundLevelChunkWithLightPacket refreshPacket = new ClientboundLevelChunkWithLightPacket(chunk, chunk.level.getLightEngine(), null, null);
+        // Paper start - Anti-Xray
+        final Map<Object, ClientboundLevelChunkWithLightPacket> refreshPackets = new HashMap<>();
         for (final ServerPlayer player : playersInRange) {
             if (player.connection == null) continue;
 
-            player.connection.send(refreshPacket);
+            final Boolean shouldModify = chunk.getLevel().chunkPacketBlockController.shouldModify(player, chunk);
+            player.connection.send(refreshPackets.computeIfAbsent(shouldModify, s -> { // Use connection to prevent creating firing event
+                return new ClientboundLevelChunkWithLightPacket(chunk, chunk.level.getLightEngine(), null, null, (Boolean) s);
+            }));
         }
+        // Paper end - Anti-Xray
     }
 
     public static PalettedContainer<BlockState> emptyPalettedBlockContainer() {
-        return new PalettedContainer<>(Block.BLOCK_STATE_REGISTRY, Blocks.AIR.defaultBlockState(), PalettedContainer.Strategy.SECTION_STATES);
+        return new PalettedContainer<>(Block.BLOCK_STATE_REGISTRY, Blocks.AIR.defaultBlockState(), PalettedContainer.Strategy.SECTION_STATES, null); // Paper - Anti-Xray - Add preset block states
     }
 
     public static Set<Long> getSentChunkKeys(final ServerPlayer player) {
diff --git a/net/minecraft/network/protocol/game/ClientboundChunksBiomesPacket.java b/net/minecraft/network/protocol/game/ClientboundChunksBiomesPacket.java
index d4872b7f4e9591b3b1c67406312905851303f521..cb41460e94161675e2ab43f4b1b5286ee38e2e13 100644
--- a/net/minecraft/network/protocol/game/ClientboundChunksBiomesPacket.java
+++ b/net/minecraft/network/protocol/game/ClientboundChunksBiomesPacket.java
@@ -70,8 +70,10 @@ public record ClientboundChunksBiomesPacket(List<ClientboundChunksBiomesPacket.C
         }
 
         public static void extractChunkData(FriendlyByteBuf buffer, LevelChunk chunk) {
+            int chunkSectionIndex = 0; // Paper - Anti-Xray
             for (LevelChunkSection levelChunkSection : chunk.getSections()) {
-                levelChunkSection.getBiomes().write(buffer);
+                levelChunkSection.getBiomes().write(buffer, null, chunkSectionIndex); // Paper - Anti-Xray
+                chunkSectionIndex++; // Paper - Anti-Xray
             }
         }
 
diff --git a/net/minecraft/network/protocol/game/ClientboundLevelChunkPacketData.java b/net/minecraft/network/protocol/game/ClientboundLevelChunkPacketData.java
index 5d1943d37dfad0c12e77179f0866851532d983e9..3aea76690bc3e35758d3bf274777130af17d8a0f 100644
--- a/net/minecraft/network/protocol/game/ClientboundLevelChunkPacketData.java
+++ b/net/minecraft/network/protocol/game/ClientboundLevelChunkPacketData.java
@@ -28,7 +28,13 @@ public class ClientboundLevelChunkPacketData {
     private final byte[] buffer;
     private final List<ClientboundLevelChunkPacketData.BlockEntityInfo> blockEntitiesData;
 
+    // Paper start - Anti-Xray - Add chunk packet info
+    @Deprecated @io.papermc.paper.annotation.DoNotUse
     public ClientboundLevelChunkPacketData(LevelChunk levelChunk) {
+        this(levelChunk, null);
+    }
+    public ClientboundLevelChunkPacketData(LevelChunk levelChunk, io.papermc.paper.antixray.ChunkPacketInfo<net.minecraft.world.level.block.state.BlockState> chunkPacketInfo) {
+        // Paper end
         this.heightmaps = new CompoundTag();
 
         for (Entry<Heightmap.Types, Heightmap> entry : levelChunk.getHeightmaps()) {
@@ -38,7 +44,11 @@ public class ClientboundLevelChunkPacketData {
         }
 
         this.buffer = new byte[calculateChunkSize(levelChunk)];
-        extractChunkData(new FriendlyByteBuf(this.getWriteBuffer()), levelChunk);
+        // Paper start - Anti-Xray - Add chunk packet info
+        if (chunkPacketInfo != null) {
+            chunkPacketInfo.setBuffer(this.buffer);
+        }
+        extractChunkData(new FriendlyByteBuf(this.getWriteBuffer()), levelChunk, chunkPacketInfo);
         this.blockEntitiesData = Lists.newArrayList();
 
         for (Entry<BlockPos, BlockEntity> entryx : levelChunk.getBlockEntities().entrySet()) {
@@ -85,9 +95,17 @@ public class ClientboundLevelChunkPacketData {
         return byteBuf;
     }
 
+    // Paper start - Anti-Xray - Add chunk packet info
+    @Deprecated @io.papermc.paper.annotation.DoNotUse
     public static void extractChunkData(FriendlyByteBuf buffer, LevelChunk chunk) {
+        ClientboundLevelChunkPacketData.extractChunkData(buffer, chunk, null);
+    }
+    public static void extractChunkData(FriendlyByteBuf buffer, LevelChunk chunk, io.papermc.paper.antixray.ChunkPacketInfo<net.minecraft.world.level.block.state.BlockState> chunkPacketInfo) {
+        int chunkSectionIndex = 0;
         for (LevelChunkSection levelChunkSection : chunk.getSections()) {
-            levelChunkSection.write(buffer);
+            levelChunkSection.write(buffer, chunkPacketInfo, chunkSectionIndex);
+            chunkSectionIndex++;
+            // Paper end  - Anti-Xray - Add chunk packet info
         }
     }
 
diff --git a/net/minecraft/network/protocol/game/ClientboundLevelChunkWithLightPacket.java b/net/minecraft/network/protocol/game/ClientboundLevelChunkWithLightPacket.java
index 3a384175f8e7f204234bbaf3081bdc20c47a0d4b..5699bc15eba92e22433a20cb8326b59f2ebd3036 100644
--- a/net/minecraft/network/protocol/game/ClientboundLevelChunkWithLightPacket.java
+++ b/net/minecraft/network/protocol/game/ClientboundLevelChunkWithLightPacket.java
@@ -18,18 +18,31 @@ public class ClientboundLevelChunkWithLightPacket implements Packet<ClientGamePa
     private final int z;
     private final ClientboundLevelChunkPacketData chunkData;
     private final ClientboundLightUpdatePacketData lightData;
-    // Paper start - Anti-Xray
+    // Paper start - Async-Anti-Xray - Ready flag for the connection, add chunk packet info
+    private volatile boolean ready;
+
+    @Override
+    public boolean isReady() {
+        return this.ready;
+    }
+
     public void setReady(final boolean ready) {
-        // Empty hook, updated by feature patch
+        this.ready = ready;
     }
-    // Paper end - Anti-Xray
 
+    @Deprecated @io.papermc.paper.annotation.DoNotUse
     public ClientboundLevelChunkWithLightPacket(LevelChunk chunk, LevelLightEngine lightEngine, @Nullable BitSet skyLight, @Nullable BitSet blockLight) {
+        this(chunk, lightEngine, skyLight, blockLight, true);
+    }
+    public ClientboundLevelChunkWithLightPacket(LevelChunk chunk, LevelLightEngine lightEngine, @Nullable BitSet skyLight, @Nullable BitSet blockLight, boolean modifyBlocks) {
+        // Paper end - Anti-Xray
         ChunkPos pos = chunk.getPos();
         this.x = pos.x;
         this.z = pos.z;
-        this.chunkData = new ClientboundLevelChunkPacketData(chunk);
+        io.papermc.paper.antixray.ChunkPacketInfo<net.minecraft.world.level.block.state.BlockState> chunkPacketInfo = modifyBlocks ? chunk.getLevel().chunkPacketBlockController.getChunkPacketInfo(this, chunk) : null; // Paper - Ant-Xray
+        this.chunkData = new ClientboundLevelChunkPacketData(chunk, chunkPacketInfo); // Paper - Anti-Xray
         this.lightData = new ClientboundLightUpdatePacketData(pos, lightEngine, skyLight, blockLight);
+        chunk.getLevel().chunkPacketBlockController.modifyBlocks(this, chunkPacketInfo); // Paper - Anti-Xray - Modify blocks
     }
 
     private ClientboundLevelChunkWithLightPacket(RegistryFriendlyByteBuf buffer) {
diff --git a/net/minecraft/server/level/ServerLevel.java b/net/minecraft/server/level/ServerLevel.java
index 7702004b68b7735043914f93b54b4413cd21ba41..4d20bda4cba578c47216d450c99389b744a59008 100644
--- a/net/minecraft/server/level/ServerLevel.java
+++ b/net/minecraft/server/level/ServerLevel.java
@@ -348,7 +348,7 @@ public class ServerLevel extends Level implements ServerEntityGetter, WorldGenLe
         org.bukkit.generator.BiomeProvider biomeProvider // CraftBukkit
     ) {
         // CraftBukkit start
-        super(serverLevelData, dimension, server.registryAccess(), levelStem.type(), false, isDebug, biomeZoomSeed, server.getMaxChainedNeighborUpdates(), gen, biomeProvider, env, spigotConfig -> server.paperConfigurations.createWorldConfig(io.papermc.paper.configuration.PaperConfigurations.createWorldContextMap(levelStorageAccess.levelDirectory.path(), serverLevelData.getLevelName(), dimension.location(), spigotConfig, server.registryAccess(), serverLevelData.getGameRules()))); // Paper - create paper world configs
+        super(serverLevelData, dimension, server.registryAccess(), levelStem.type(), false, isDebug, biomeZoomSeed, server.getMaxChainedNeighborUpdates(), gen, biomeProvider, env, spigotConfig -> server.paperConfigurations.createWorldConfig(io.papermc.paper.configuration.PaperConfigurations.createWorldContextMap(levelStorageAccess.levelDirectory.path(), serverLevelData.getLevelName(), dimension.location(), spigotConfig, server.registryAccess(), serverLevelData.getGameRules())), dispatcher); // Paper - create paper world configs; Async-Anti-Xray: Pass executor
         this.pvpMode = server.isPvpAllowed();
         this.levelStorageAccess = levelStorageAccess;
         this.uuid = org.bukkit.craftbukkit.util.WorldUUID.getUUID(levelStorageAccess.levelDirectory.path().toFile());
diff --git a/net/minecraft/server/level/ServerPlayerGameMode.java b/net/minecraft/server/level/ServerPlayerGameMode.java
index 23d241e98f37979701f80fb6f7b76954bd699ad6..fd7ad2b1bffe3880def0f0c9a7ed8de5088ecd71 100644
--- a/net/minecraft/server/level/ServerPlayerGameMode.java
+++ b/net/minecraft/server/level/ServerPlayerGameMode.java
@@ -298,6 +298,7 @@ public class ServerPlayerGameMode {
                 org.bukkit.craftbukkit.event.CraftEventFactory.callBlockDamageAbortEvent(this.player, pos, this.player.getInventory().getSelected()); // CraftBukkit
             }
         }
+        this.level.chunkPacketBlockController.onPlayerLeftClickBlock(this, pos, action, face, maxBuildHeight, sequence); // Paper - Anti-Xray
     }
 
     public void destroyAndAck(BlockPos pos, int sequence, String message) {
diff --git a/net/minecraft/server/network/PlayerChunkSender.java b/net/minecraft/server/network/PlayerChunkSender.java
index 342bc843c384761e883de861044f4f8930ae8763..14878690a88fd4de3e2c127086607e6c819c636c 100644
--- a/net/minecraft/server/network/PlayerChunkSender.java
+++ b/net/minecraft/server/network/PlayerChunkSender.java
@@ -78,8 +78,11 @@ public class PlayerChunkSender {
         }
     }
 
-    private static void sendChunk(ServerGamePacketListenerImpl packetListener, ServerLevel level, LevelChunk chunk) {
-        packetListener.send(new ClientboundLevelChunkWithLightPacket(chunk, level.getLightEngine(), null, null));
+    // Paper start - Anti-Xray
+    public static void sendChunk(ServerGamePacketListenerImpl packetListener, ServerLevel level, LevelChunk chunk) {
+        final boolean shouldModify = level.chunkPacketBlockController.shouldModify(packetListener.player, chunk);
+        packetListener.send(new ClientboundLevelChunkWithLightPacket(chunk, level.getLightEngine(), null, null, shouldModify));
+        // Paper end - Anti-Xray
         // Paper start - PlayerChunkLoadEvent
         if (io.papermc.paper.event.packet.PlayerChunkLoadEvent.getHandlerList().getRegisteredListeners().length > 0) {
             new io.papermc.paper.event.packet.PlayerChunkLoadEvent(new org.bukkit.craftbukkit.CraftChunk(chunk), packetListener.getPlayer().getBukkitEntity()).callEvent();
diff --git a/net/minecraft/server/players/PlayerList.java b/net/minecraft/server/players/PlayerList.java
index 8a93d1034eb0dab4b4010d52ddbb0caa5697416d..bafeeab3edbc73f6f86474e18ab4a3d96ce17157 100644
--- a/net/minecraft/server/players/PlayerList.java
+++ b/net/minecraft/server/players/PlayerList.java
@@ -404,7 +404,7 @@ public abstract class PlayerList {
                     .getOrThrow(net.minecraft.world.level.biome.Biomes.PLAINS);
             player.connection.send(new net.minecraft.network.protocol.game.ClientboundLevelChunkWithLightPacket(
                     new net.minecraft.world.level.chunk.EmptyLevelChunk(serverLevel, player.chunkPosition(), plains),
-                    serverLevel.getLightEngine(), (java.util.BitSet)null, (java.util.BitSet) null)
+                    serverLevel.getLightEngine(), (java.util.BitSet)null, (java.util.BitSet) null, true) // Paper - Anti-Xray
             );
         }
         // Paper end - Send empty chunk
diff --git a/net/minecraft/world/level/Level.java b/net/minecraft/world/level/Level.java
index 13dbd0da80b2199519370ac6e993ace53f42c1ea..0e4ab448755632696c4326f1df9f3855cd38a64d 100644
--- a/net/minecraft/world/level/Level.java
+++ b/net/minecraft/world/level/Level.java
@@ -168,6 +168,7 @@ public abstract class Level implements LevelAccessor, AutoCloseable {
     }
     // Paper end - add paper world config
 
+    public final io.papermc.paper.antixray.ChunkPacketBlockController chunkPacketBlockController; // Paper - Anti-Xray
     public static BlockPos lastPhysicsProblem; // Spigot
     private org.spigotmc.TickLimiter entityLimiter;
     private org.spigotmc.TickLimiter tileLimiter;
@@ -214,7 +215,8 @@ public abstract class Level implements LevelAccessor, AutoCloseable {
         org.bukkit.generator.BiomeProvider biomeProvider, // CraftBukkit
         org.bukkit.World.Environment env, // CraftBukkit
         java.util.function.Function<org.spigotmc.SpigotWorldConfig, // Spigot - create per world config
-        io.papermc.paper.configuration.WorldConfiguration> paperWorldConfigCreator // Paper - create paper world config
+        io.papermc.paper.configuration.WorldConfiguration> paperWorldConfigCreator, // Paper - create paper world config
+        java.util.concurrent.Executor executor // Paper - Anti-Xray
     ) {
         this.spigotConfig = new org.spigotmc.SpigotWorldConfig(((net.minecraft.world.level.storage.PrimaryLevelData) levelData).getLevelName()); // Spigot
         this.paperConfig = paperWorldConfigCreator.apply(this.spigotConfig); // Paper - create paper world config
@@ -295,6 +297,7 @@ public abstract class Level implements LevelAccessor, AutoCloseable {
         // CraftBukkit end
         this.entityLimiter = new org.spigotmc.TickLimiter(this.spigotConfig.entityMaxTickTime);
         this.tileLimiter = new org.spigotmc.TickLimiter(this.spigotConfig.tileMaxTickTime);
+        this.chunkPacketBlockController = this.paperConfig().anticheat.antiXray.enabled ? new io.papermc.paper.antixray.ChunkPacketBlockControllerAntiXray(this, executor) : io.papermc.paper.antixray.ChunkPacketBlockController.NO_OPERATION_INSTANCE; // Paper - Anti-Xray
     }
 
     // Paper start - Cancel hit for vanished players
@@ -495,6 +498,7 @@ public abstract class Level implements LevelAccessor, AutoCloseable {
             // CraftBukkit end
 
             BlockState blockState = chunkAt.setBlockState(pos, state, (flags & 64) != 0, (flags & 1024) == 0); // CraftBukkit custom NO_PLACE flag
+            this.chunkPacketBlockController.onBlockChange(this, pos, state, blockState, flags, recursionLeft); // Paper - Anti-Xray
 
             if (blockState == null) {
                 // CraftBukkit start - remove blockstate if failed (or the same)
diff --git a/net/minecraft/world/level/chunk/ChunkAccess.java b/net/minecraft/world/level/chunk/ChunkAccess.java
index 809b3c37d3749c76c3c243cd91c593d03693e9b3..860d1c9729c4ee97ec6f40f7aa969829070b27c0 100644
--- a/net/minecraft/world/level/chunk/ChunkAccess.java
+++ b/net/minecraft/world/level/chunk/ChunkAccess.java
@@ -114,14 +114,14 @@ public abstract class ChunkAccess implements BiomeManager.NoiseBiomeSource, Ligh
             }
         }
 
-        replaceMissingSections(biomeRegistry, this.sections);
+        this.replaceMissingSections(biomeRegistry, this.sections); // Paper - Anti-Xray - make it a non-static method
         this.biomeRegistry = biomeRegistry; // CraftBukkit
     }
 
-    private static void replaceMissingSections(Registry<Biome> biomeRegistry, LevelChunkSection[] sections) {
+    private void replaceMissingSections(Registry<Biome> biomeRegistry, LevelChunkSection[] sections) { // Paper - Anti-Xray - make it a non-static method
         for (int i = 0; i < sections.length; i++) {
             if (sections[i] == null) {
-                sections[i] = new LevelChunkSection(biomeRegistry);
+                sections[i] = new LevelChunkSection(biomeRegistry, this.levelHeightAccessor instanceof net.minecraft.world.level.Level ? (net.minecraft.world.level.Level) this.levelHeightAccessor : null, this.chunkPos, this.levelHeightAccessor.getSectionYFromSectionIndex(i)); // Paper - Anti-Xray - Add parameters
             }
         }
     }
diff --git a/net/minecraft/world/level/chunk/LevelChunk.java b/net/minecraft/world/level/chunk/LevelChunk.java
index 51a136cf015de730ca0d1b48cf618a2ed69ea89f..96b0342ab7b922aa16d07b6c00542e6cb66c974a 100644
--- a/net/minecraft/world/level/chunk/LevelChunk.java
+++ b/net/minecraft/world/level/chunk/LevelChunk.java
@@ -109,7 +109,7 @@ public class LevelChunk extends ChunkAccess {
         @Nullable LevelChunk.PostLoadProcessor postLoad,
         @Nullable BlendingData blendingData
     ) {
-        super(pos, data, level, level.registryAccess().lookupOrThrow(Registries.BIOME), inhabitedTime, sections, blendingData);
+        super(pos, data, level, net.minecraft.server.MinecraftServer.getServer().registryAccess().lookupOrThrow(Registries.BIOME), inhabitedTime, sections, blendingData); // Paper - Anti-Xray - The world isn't ready yet, use server singleton for registry
         this.level = (net.minecraft.server.level.ServerLevel) level; // CraftBukkit - type
         this.gameEventListenerRegistrySections = new Int2ObjectOpenHashMap<>();
 
diff --git a/net/minecraft/world/level/chunk/LevelChunkSection.java b/net/minecraft/world/level/chunk/LevelChunkSection.java
index baa9f3e2e6e45c250930658e82bad70a3a292b05..fc21c3268c4b4fda2933d71f0913db28e3796653 100644
--- a/net/minecraft/world/level/chunk/LevelChunkSection.java
+++ b/net/minecraft/world/level/chunk/LevelChunkSection.java
@@ -38,9 +38,15 @@ public class LevelChunkSection {
         this.recalcBlockCounts();
     }
 
+    // Paper start - Anti-Xray - Add parameters
+    @Deprecated @io.papermc.paper.annotation.DoNotUse
     public LevelChunkSection(Registry<Biome> biomeRegistry) {
-        this.states = new PalettedContainer<>(Block.BLOCK_STATE_REGISTRY, Blocks.AIR.defaultBlockState(), PalettedContainer.Strategy.SECTION_STATES);
-        this.biomes = new PalettedContainer<>(biomeRegistry.asHolderIdMap(), biomeRegistry.getOrThrow(Biomes.PLAINS), PalettedContainer.Strategy.SECTION_BIOMES);
+        this(biomeRegistry, null, null, 0);
+    }
+    public LevelChunkSection(Registry<Biome> biomeRegistry, net.minecraft.world.level.Level level, net.minecraft.world.level.ChunkPos chunkPos, int chunkSectionY) {
+        // Paper end - Anti-Xray
+        this.states = new PalettedContainer<>(Block.BLOCK_STATE_REGISTRY, Blocks.AIR.defaultBlockState(), PalettedContainer.Strategy.SECTION_STATES, level == null || level.chunkPacketBlockController == null ? null : level.chunkPacketBlockController.getPresetBlockStates(level, chunkPos, chunkSectionY)); // Paper - Anti-Xray - Add preset block states
+        this.biomes = new PalettedContainer<>(biomeRegistry.asHolderIdMap(), biomeRegistry.getOrThrow(Biomes.PLAINS), PalettedContainer.Strategy.SECTION_BIOMES, null); // Paper - Anti-Xray - Add preset biomes
     }
 
     public BlockState getBlockState(int x, int y, int z) {
@@ -168,10 +174,16 @@ public class LevelChunkSection {
         this.biomes = palettedContainer;
     }
 
+    // Paper start - Anti-Xray - Add chunk packet info
+    @Deprecated @io.papermc.paper.annotation.DoNotUse
     public void write(FriendlyByteBuf buffer) {
+        this.write(buffer, null, 0);
+    }
+    public void write(FriendlyByteBuf buffer, io.papermc.paper.antixray.ChunkPacketInfo<BlockState> chunkPacketInfo, int chunkSectionIndex) {
         buffer.writeShort(this.nonEmptyBlockCount);
-        this.states.write(buffer);
-        this.biomes.write(buffer);
+        this.states.write(buffer, chunkPacketInfo, chunkSectionIndex);
+        this.biomes.write(buffer, null, chunkSectionIndex);
+        // Paper end - Anti-Xray
     }
 
     public int getSerializedSize() {
diff --git a/net/minecraft/world/level/chunk/PalettedContainer.java b/net/minecraft/world/level/chunk/PalettedContainer.java
index e8ec28ce3fe13561b45c4654e174776d9d2d7b71..a6028a54c75de068515e95913b21160ab4326985 100644
--- a/net/minecraft/world/level/chunk/PalettedContainer.java
+++ b/net/minecraft/world/level/chunk/PalettedContainer.java
@@ -28,6 +28,7 @@ public class PalettedContainer<T> implements PaletteResize<T>, PalettedContainer
     private static final int MIN_PALETTE_BITS = 0;
     private final PaletteResize<T> dummyPaletteResize = (bits, objectAdded) -> 0;
     public final IdMap<T> registry;
+    private final T @org.jetbrains.annotations.Nullable [] presetValues; // Paper - Anti-Xray - Add preset values
     private volatile PalettedContainer.Data<T> data;
     private final PalettedContainer.Strategy strategy;
     //private final ThreadingDetector threadingDetector = new ThreadingDetector("PalettedContainer"); // Paper - unused
@@ -40,13 +41,21 @@ public class PalettedContainer<T> implements PaletteResize<T>, PalettedContainer
         // this.threadingDetector.checkAndUnlock(); // Paper - disable this - use proper synchronization
     }
 
+    // Paper start - Anti-Xray - Add preset values
+    @Deprecated @io.papermc.paper.annotation.DoNotUse
     public static <T> Codec<PalettedContainer<T>> codecRW(IdMap<T> registry, Codec<T> codec, PalettedContainer.Strategy strategy, T value) {
-        PalettedContainerRO.Unpacker<T, PalettedContainer<T>> unpacker = PalettedContainer::unpack;
+        return PalettedContainer.codecRW(registry, codec, strategy, value, null);
+    }
+    public static <T> Codec<PalettedContainer<T>> codecRW(IdMap<T> registry, Codec<T> codec, PalettedContainer.Strategy strategy, T value, T @org.jetbrains.annotations.Nullable [] presetValues) {
+        PalettedContainerRO.Unpacker<T, PalettedContainer<T>> unpacker = (idListx, paletteProviderx, serialized) -> {
+            return unpack(idListx, paletteProviderx, serialized, value, presetValues);
+        };
+        // Paper end
         return codec(registry, codec, strategy, value, unpacker);
     }
 
     public static <T> Codec<PalettedContainerRO<T>> codecRO(IdMap<T> registry, Codec<T> codec, PalettedContainer.Strategy strategy, T value) {
-        PalettedContainerRO.Unpacker<T, PalettedContainerRO<T>> unpacker = (registry1, strategy1, packedData) -> unpack(registry1, strategy1, packedData)
+        PalettedContainerRO.Unpacker<T, PalettedContainerRO<T>> unpacker = (registry1, strategy1, packedData) -> unpack(registry1, strategy1, packedData, value, null) // Paper - Anti-Xray - Add preset values
             .map(container -> (PalettedContainerRO<T>)container);
         return codec(registry, codec, strategy, value, unpacker);
     }
@@ -66,27 +75,66 @@ public class PalettedContainer<T> implements PaletteResize<T>, PalettedContainer
             );
     }
 
+    // Paper start - Anti-Xray - Add preset values
+    @Deprecated @io.papermc.paper.annotation.DoNotUse
+    public PalettedContainer(IdMap<T> registry, PalettedContainer.Strategy strategy, PalettedContainer.Configuration<T> configuration, BitStorage storage, List<T> values) {
+        this(registry, strategy, configuration, storage, values, null, null);
+    }
     public PalettedContainer(
-        IdMap<T> registry, PalettedContainer.Strategy strategy, PalettedContainer.Configuration<T> configuration, BitStorage storage, List<T> values
+        IdMap<T> registry, PalettedContainer.Strategy strategy, PalettedContainer.Configuration<T> configuration, BitStorage storage, List<T> values, T defaultValue, T @org.jetbrains.annotations.Nullable [] presetValues
     ) {
+        this.presetValues = presetValues;
         this.registry = registry;
         this.strategy = strategy;
         this.data = new PalettedContainer.Data<>(configuration, storage, configuration.factory().create(configuration.bits(), registry, this, values));
+        if (presetValues != null && (configuration.factory() == PalettedContainer.Strategy.SINGLE_VALUE_PALETTE_FACTORY ? this.data.palette.valueFor(0) != defaultValue : configuration.factory() != PalettedContainer.Strategy.GLOBAL_PALETTE_FACTORY)) {
+            // In 1.18 Mojang unfortunately removed code that already handled possible resize operations on read from disk for us
+            // We readd this here but in a smarter way than it was before
+            int maxSize = 1 << configuration.bits();
+
+            for (T presetValue : presetValues) {
+                if (this.data.palette.getSize() >= maxSize) {
+                    java.util.Set<T> allValues = new java.util.HashSet<>(values);
+                    allValues.addAll(Arrays.asList(presetValues));
+                    int newBits = Mth.ceillog2(allValues.size());
+
+                    if (newBits > configuration.bits()) {
+                        this.onResize(newBits, null);
+                    }
+
+                    break;
+                }
+
+                this.data.palette.idFor(presetValue);
+            }
+        }
+        // Paper end
     }
 
-    private PalettedContainer(IdMap<T> registry, PalettedContainer.Strategy strategy, PalettedContainer.Data<T> data) {
+    // Paper start - Anti-Xray - Add preset values
+    private PalettedContainer(IdMap<T> registry, PalettedContainer.Strategy strategy, PalettedContainer.Data<T> data, T @org.jetbrains.annotations.Nullable [] presetValues) {
+        this.presetValues = presetValues;
+        // Paper end - Anti-Xray
         this.registry = registry;
         this.strategy = strategy;
         this.data = data;
     }
 
-    private PalettedContainer(PalettedContainer<T> other) {
+    private PalettedContainer(PalettedContainer<T> other, T @org.jetbrains.annotations.Nullable [] presetValues) { // Paper - Anti-Xray - Add preset values
+        this.presetValues = presetValues; // Paper - Anti-Xray - Add preset values
         this.registry = other.registry;
         this.strategy = other.strategy;
         this.data = other.data.copy(this);
     }
 
+    // Paper start - Anti-Xray - Add preset values
+    @Deprecated @io.papermc.paper.annotation.DoNotUse
     public PalettedContainer(IdMap<T> registry, T palette, PalettedContainer.Strategy strategy) {
+        this(registry, palette, strategy, null);
+    }
+    public PalettedContainer(IdMap<T> registry, T palette, PalettedContainer.Strategy strategy, T @org.jetbrains.annotations.Nullable [] presetValues) {
+        this.presetValues = presetValues;
+        // Paper end - Anti-Xray
         this.strategy = strategy;
         this.registry = registry;
         this.data = this.createOrReuseData(null, 0);
@@ -101,11 +149,30 @@ public class PalettedContainer<T> implements PaletteResize<T>, PalettedContainer
     @Override
     public synchronized int onResize(int bits, T objectAdded) { // Paper - synchronize
         PalettedContainer.Data<T> data = this.data;
+        // Paper start - Anti-Xray - Add preset values
+        if (this.presetValues != null && objectAdded != null && data.configuration().factory() == PalettedContainer.Strategy.SINGLE_VALUE_PALETTE_FACTORY) {
+            int duplicates = 0;
+            List<T> presetValues = Arrays.asList(this.presetValues);
+            duplicates += presetValues.contains(objectAdded) ? 1 : 0;
+            duplicates += presetValues.contains(data.palette.valueFor(0)) ? 1 : 0;
+            bits = Mth.ceillog2((1 << this.strategy.calculateBitsForSerialization(this.registry, 1 << bits)) + presetValues.size() - duplicates);
+        }
+        // Paper end - Anti-Xray
         PalettedContainer.Data<T> data1 = this.createOrReuseData(data, bits);
         data1.copyFrom(data.palette, data.storage);
         this.data = data1;
-        return data1.palette.idFor(objectAdded);
+        // Paper start - Anti-Xray
+        this.addPresetValues();
+        return objectAdded == null ? -1 : data1.palette.idFor(objectAdded);
+    }
+    private void addPresetValues() {
+        if (this.presetValues != null && this.data.configuration().factory() != PalettedContainer.Strategy.GLOBAL_PALETTE_FACTORY) {
+            for (T presetValue : this.presetValues) {
+                this.data.palette.idFor(presetValue);
+            }
+        }
     }
+    // Paper end - Anti-Xray
 
     public synchronized T getAndSet(int x, int y, int z, T state) { // Paper - synchronize
         this.acquire();
@@ -172,24 +239,35 @@ public class PalettedContainer<T> implements PaletteResize<T>, PalettedContainer
             data.palette.read(buffer);
             buffer.readLongArray(data.storage.getRaw());
             this.data = data;
+            this.addPresetValues(); // Paper - Anti-Xray - Add preset values (inefficient, but this isn't used by the server)
         } finally {
             this.release();
         }
     }
 
+    // Paper start - Anti-Xray; Add chunk packet info
     @Override
-    public synchronized void write(FriendlyByteBuf buffer) { // Paper - synchronize
+    @Deprecated @io.papermc.paper.annotation.DoNotUse
+    public void write(FriendlyByteBuf buffer) {
+        this.write(buffer, null, 0);
+    }
+    @Override
+    public synchronized void write(FriendlyByteBuf buffer, @Nullable io.papermc.paper.antixray.ChunkPacketInfo<T> chunkPacketInfo, int chunkSectionIndex) { // Paper - Synchronize
         this.acquire();
 
         try {
-            this.data.write(buffer);
+            this.data.write(buffer, chunkPacketInfo, chunkSectionIndex);
+            if (chunkPacketInfo != null) {
+                chunkPacketInfo.setPresetValues(chunkSectionIndex, this.presetValues);
+            }
+            // Paper end - Anti-Xray
         } finally {
             this.release();
         }
     }
 
     private static <T> DataResult<PalettedContainer<T>> unpack(
-        IdMap<T> registry, PalettedContainer.Strategy strategy, PalettedContainerRO.PackedData<T> packedData
+        IdMap<T> registry, PalettedContainer.Strategy strategy, PalettedContainerRO.PackedData<T> packedData, T defaultValue, T @org.jetbrains.annotations.Nullable [] presetValues // Paper - Anti-Xray - Add preset values
     ) {
         List<T> list = packedData.paletteEntries();
         int size = strategy.size();
@@ -222,7 +300,7 @@ public class PalettedContainer<T> implements PaletteResize<T>, PalettedContainer
             }
         }
 
-        return DataResult.success(new PalettedContainer<>(registry, strategy, configuration, bitStorage, list));
+        return DataResult.success(new PalettedContainer<>(registry, strategy, configuration, bitStorage, list, defaultValue, presetValues)); // Paper - Anti-Xray - Add preset values
     }
 
     @Override
@@ -280,12 +358,12 @@ public class PalettedContainer<T> implements PaletteResize<T>, PalettedContainer
 
     @Override
     public PalettedContainer<T> copy() {
-        return new PalettedContainer<>(this);
+        return new PalettedContainer<>(this, this.presetValues); // Paper - Anti-Xray - Add preset values
     }
 
     @Override
     public PalettedContainer<T> recreate() {
-        return new PalettedContainer<>(this.registry, this.data.palette.valueFor(0), this.strategy);
+        return new PalettedContainer<>(this.registry, this.data.palette.valueFor(0), this.strategy, this.presetValues); // Paper - Anti-Xray - Add preset values
     }
 
     @Override
@@ -324,9 +402,16 @@ public class PalettedContainer<T> implements PaletteResize<T>, PalettedContainer
             return 1 + this.palette.getSerializedSize() + VarInt.getByteSize(this.storage.getRaw().length) + this.storage.getRaw().length * 8;
         }
 
-        public void write(FriendlyByteBuf buffer) {
+        // Paper start - Anti-Xray - Add chunk packet info
+        public void write(FriendlyByteBuf buffer, @Nullable io.papermc.paper.antixray.ChunkPacketInfo<T> chunkPacketInfo, int chunkSectionIndex) {
             buffer.writeByte(this.storage.getBits());
             this.palette.write(buffer);
+            if (chunkPacketInfo != null) {
+                chunkPacketInfo.setBits(chunkSectionIndex, this.configuration.bits());
+                chunkPacketInfo.setPalette(chunkSectionIndex, this.palette);
+                chunkPacketInfo.setIndex(chunkSectionIndex, buffer.writerIndex() + VarInt.getByteSize(this.storage.getRaw().length));
+            }
+            // Paper end
             buffer.writeLongArray(this.storage.getRaw());
         }
 
diff --git a/net/minecraft/world/level/chunk/PalettedContainerRO.java b/net/minecraft/world/level/chunk/PalettedContainerRO.java
index bfbb1a2bb4abbb369a24f2f01439e9ea3e16794b..8d6ed8be4d93f7d4e6ea80c351020d88ee98aa4d 100644
--- a/net/minecraft/world/level/chunk/PalettedContainerRO.java
+++ b/net/minecraft/world/level/chunk/PalettedContainerRO.java
@@ -14,7 +14,10 @@ public interface PalettedContainerRO<T> {
 
     void getAll(Consumer<T> consumer);
 
-    void write(FriendlyByteBuf buffer);
+    // Paper start - Anti-Xray - Add chunk packet info
+    @Deprecated @io.papermc.paper.annotation.DoNotUse void write(FriendlyByteBuf buffer);
+    void write(FriendlyByteBuf buffer, @javax.annotation.Nullable io.papermc.paper.antixray.ChunkPacketInfo<T> chunkPacketInfo, int chunkSectionIndex);
+    // Paper end
 
     int getSerializedSize();
 
diff --git a/net/minecraft/world/level/chunk/storage/SerializableChunkData.java b/net/minecraft/world/level/chunk/storage/SerializableChunkData.java
index 37437a86d74291fab1de9495008aafb15dfadce0..cf6e2053d81f7b0f8c8e58b9c0fad3285ebc047d 100644
--- a/net/minecraft/world/level/chunk/storage/SerializableChunkData.java
+++ b/net/minecraft/world/level/chunk/storage/SerializableChunkData.java
@@ -94,7 +94,7 @@ public record SerializableChunkData(
     , @Nullable net.minecraft.nbt.Tag persistentDataContainer // CraftBukkit - persistentDataContainer
 ) {
     public static final Codec<PalettedContainer<BlockState>> BLOCK_STATE_CODEC = PalettedContainer.codecRW(
-        Block.BLOCK_STATE_REGISTRY, BlockState.CODEC, PalettedContainer.Strategy.SECTION_STATES, Blocks.AIR.defaultBlockState()
+        Block.BLOCK_STATE_REGISTRY, BlockState.CODEC, PalettedContainer.Strategy.SECTION_STATES, Blocks.AIR.defaultBlockState(), null // Paper - Anti-Xray
     );
     private static final Logger LOGGER = LogUtils.getLogger();
     private static final String TAG_UPGRADE_DATA = "UpgradeData";
@@ -128,6 +128,7 @@ public record SerializableChunkData(
 
     @Nullable
     public static SerializableChunkData parse(LevelHeightAccessor levelHeightAccessor, RegistryAccess registries, CompoundTag tag) {
+        net.minecraft.server.level.ServerLevel serverLevel = (net.minecraft.server.level.ServerLevel) levelHeightAccessor; // Paper - Anti-Xray This is is seemingly only called from ChunkMap, where, we have a server level. We'll fight this later if needed.
         if (!tag.contains("Status", 8)) {
             return null;
         } else {
@@ -212,18 +213,21 @@ public record SerializableChunkData(
             Codec<PalettedContainer<Holder<Biome>>> codec = makeBiomeCodecRW(registry); // CraftBukkit - read/write
 
             for (int i2 = 0; i2 < list7.size(); i2++) {
-                CompoundTag compound2 = list7.getCompound(i2);
+                CompoundTag compound2 = list7.getCompound(i2); final CompoundTag sectionData = compound2; // Paper - Anti-Xray - OBFHELPER
                 int _byte = compound2.getByte("Y");
                 LevelChunkSection levelChunkSection;
                 if (_byte >= levelHeightAccessor.getMinSectionY() && _byte <= levelHeightAccessor.getMaxSectionY()) {
+                    // Paper start - Anti-Xray - Add preset block states
+                    BlockState[] presetBlockStates = serverLevel.chunkPacketBlockController.getPresetBlockStates(serverLevel, chunkPos, _byte);
                     PalettedContainer<BlockState> palettedContainer;
                     if (compound2.contains("block_states", 10)) {
-                        palettedContainer = BLOCK_STATE_CODEC.parse(NbtOps.INSTANCE, compound2.getCompound("block_states"))
+                        Codec<PalettedContainer<BlockState>> blockStateCodec = presetBlockStates == null ? BLOCK_STATE_CODEC : PalettedContainer.codecRW(Block.BLOCK_STATE_REGISTRY, BlockState.CODEC, PalettedContainer.Strategy.SECTION_STATES, Blocks.AIR.defaultBlockState(), presetBlockStates); // Paper - Anti-Xray
+                        palettedContainer = blockStateCodec.parse(NbtOps.INSTANCE, sectionData.getCompound("block_states")) // Paper - Anti-Xray
                             .promotePartial(string -> logErrors(chunkPos, _byte, string))
                             .getOrThrow(SerializableChunkData.ChunkReadException::new);
                     } else {
                         palettedContainer = new PalettedContainer<>(
-                            Block.BLOCK_STATE_REGISTRY, Blocks.AIR.defaultBlockState(), PalettedContainer.Strategy.SECTION_STATES
+                            Block.BLOCK_STATE_REGISTRY, Blocks.AIR.defaultBlockState(), PalettedContainer.Strategy.SECTION_STATES, presetBlockStates // Paper - Anti-Xray
                         );
                     }
 
@@ -234,7 +238,7 @@ public record SerializableChunkData(
                             .getOrThrow(SerializableChunkData.ChunkReadException::new);
                     } else {
                         palettedContainerRo = new PalettedContainer<>(
-                            registry.asHolderIdMap(), registry.getOrThrow(Biomes.PLAINS), PalettedContainer.Strategy.SECTION_BIOMES
+                            registry.asHolderIdMap(), registry.getOrThrow(Biomes.PLAINS), PalettedContainer.Strategy.SECTION_BIOMES, null // Paper - Anti-Xray - Add preset biomes
                         );
                     }
 
@@ -414,7 +418,7 @@ public record SerializableChunkData(
 
     // CraftBukkit start - read/write
     private static Codec<PalettedContainer<Holder<Biome>>> makeBiomeCodecRW(Registry<Biome> iregistry) {
-        return PalettedContainer.codecRW(iregistry.asHolderIdMap(), iregistry.holderByNameCodec(), PalettedContainer.Strategy.SECTION_BIOMES, iregistry.getOrThrow(Biomes.PLAINS));
+        return PalettedContainer.codecRW(iregistry.asHolderIdMap(), iregistry.holderByNameCodec(), PalettedContainer.Strategy.SECTION_BIOMES, iregistry.getOrThrow(Biomes.PLAINS), null); // Paper - Anti-Xray - Add preset biomes
     }
     // CraftBukkit end