Packet obfuscation and reduction

patches/server/0001-Build-Changes.patch

@@ -5,10 +5,10 @@ Subject: [PATCH] Build Changes
 
 
 diff --git a/build.gradle.kts b/build.gradle.kts
-index d80cfcb94db51440b5d0aa589a9a3d8a4189a9aa..9dbad4407dcf1a7070d5c5a692473cf57a4543e7 100644
+index cb1a931417073908be5c7aa1af710477775b3dbd..0c3c936990f161eb3de9a33f8983e4da571befac 100644
 --- a/build.gradle.kts
 +++ b/build.gradle.kts
-@@ -29,8 +29,8 @@ repositories {
+@@ -28,8 +28,8 @@ repositories {
  }
  
  dependencies {
@@ -19,7 +19,7 @@ index d80cfcb94db51440b5d0aa589a9a3d8a4189a9aa..9dbad4407dcf1a7070d5c5a692473cf5
      // Paper start
      implementation("org.jline:jline-terminal-jansi:3.12.1")
      implementation("net.minecrell:terminalconsoleappender:1.2.0")
-@@ -82,7 +82,7 @@ tasks.jar {
+@@ -81,7 +81,7 @@ tasks.jar {
          attributes(
              "Main-Class" to "org.bukkit.craftbukkit.Main",
              "Implementation-Title" to "CraftBukkit",
@@ -28,7 +28,7 @@ index d80cfcb94db51440b5d0aa589a9a3d8a4189a9aa..9dbad4407dcf1a7070d5c5a692473cf5
              "Implementation-Vendor" to date, // Paper
              "Specification-Title" to "Bukkit",
              "Specification-Version" to project.version,
-@@ -207,7 +207,7 @@ tasks.test {
+@@ -206,7 +206,7 @@ tasks.test {
  fun TaskContainer.registerRunTask(
      name: String, block: JavaExec.() -> Unit
  ): TaskProvider<JavaExec> = register<JavaExec>(name) {
@@ -51,10 +51,10 @@ index fe6d5051b139cd6079e288ffdf20e30fdd46fdda..c3c2b44c998ccb73594e4f33a571508a
  
      public SystemReport fillSystemReport(SystemReport details) {
 diff --git a/src/main/java/org/bukkit/craftbukkit/CraftServer.java b/src/main/java/org/bukkit/craftbukkit/CraftServer.java
-index f925130552cb4ff2f813b1ddae9ac2f915e17bd5..7df81489dd9d3c7ed84b3b6bdf2b724903fbcdc4 100644
+index 0adb686d690e1be0c5540625efbecc46bac5d045..d32b296d63e8f16ad4ba6e5e8da259d2905098ef 100644
 --- a/src/main/java/org/bukkit/craftbukkit/CraftServer.java
 +++ b/src/main/java/org/bukkit/craftbukkit/CraftServer.java
-@@ -249,7 +249,7 @@ import javax.annotation.Nullable; // Paper
+@@ -251,7 +251,7 @@ import javax.annotation.Nullable; // Paper
  import javax.annotation.Nonnull; // Paper
  
  public final class CraftServer implements Server {

patches/server/0004-Set-BlockData-without-light-update.patch

@@ -27,10 +27,10 @@ index 21d1e0c9c471e9e556b5bd70166a769b46105c7a..d46dc12001bd46596c3bb2e24144bbe4
              return false;
          } else {
 diff --git a/src/main/java/net/minecraft/world/level/Level.java b/src/main/java/net/minecraft/world/level/Level.java
-index b93056b91e7ebd49e6ddb53ccb6c05c056088df9..a9315b7acec3c2ccaf879e0f1d45c062d8e201b1 100644
+index f936e9f9a9fa655fa997d6862b5ed54c04169d35..465a1e179f6ae43d253d692255c8fe144179efe3 100644
 --- a/src/main/java/net/minecraft/world/level/Level.java
 +++ b/src/main/java/net/minecraft/world/level/Level.java
-@@ -550,12 +550,12 @@ public abstract class Level implements LevelAccessor, AutoCloseable {
+@@ -552,12 +552,12 @@ public abstract class Level implements LevelAccessor, AutoCloseable {
      }
  
      @Override
@@ -46,7 +46,7 @@ index b93056b91e7ebd49e6ddb53ccb6c05c056088df9..a9315b7acec3c2ccaf879e0f1d45c062
          // CraftBukkit start - tree generation
          if (this.captureTreeGeneration) {
              // Paper start
-@@ -602,7 +602,7 @@ public abstract class Level implements LevelAccessor, AutoCloseable {
+@@ -604,7 +604,7 @@ public abstract class Level implements LevelAccessor, AutoCloseable {
              } else {
                  BlockState iblockdata2 = this.getBlockState(pos);
  
@@ -55,7 +55,7 @@ index b93056b91e7ebd49e6ddb53ccb6c05c056088df9..a9315b7acec3c2ccaf879e0f1d45c062
                      this.getProfiler().push("queueCheckLight");
                      this.getChunkSource().getLightEngine().checkBlock(pos);
                      this.getProfiler().pop();
-@@ -749,7 +749,7 @@ public abstract class Level implements LevelAccessor, AutoCloseable {
+@@ -751,7 +751,7 @@ public abstract class Level implements LevelAccessor, AutoCloseable {
                  Block.dropResources(iblockdata, this, pos, tileentity, breakingEntity, ItemStack.EMPTY);
              }
  

patches/server/0008-Track-Player-throughout-entire-block-destroy.patch

@@ -37,10 +37,10 @@ index 3e5e358e24bd84a05785a9391526f316475e95ff..9914a92040a63b6102eb6171f058ea1c
              CompoundTag newData = this.getTagClone();
              int newCount = this.getCount();
 diff --git a/src/main/java/net/minecraft/world/level/Level.java b/src/main/java/net/minecraft/world/level/Level.java
-index a9315b7acec3c2ccaf879e0f1d45c062d8e201b1..7dec61b831860e372f1785c2ae838cb3ad2fc623 100644
+index 465a1e179f6ae43d253d692255c8fe144179efe3..46a1b0519aaccc2b5625104d42168254bfb27cd9 100644
 --- a/src/main/java/net/minecraft/world/level/Level.java
 +++ b/src/main/java/net/minecraft/world/level/Level.java
-@@ -175,6 +175,27 @@ public abstract class Level implements LevelAccessor, AutoCloseable {
+@@ -176,6 +176,27 @@ public abstract class Level implements LevelAccessor, AutoCloseable {
      public final Map<Explosion.CacheKey, Float> explosionDensityCache = new HashMap<>(); // Paper - Optimize explosions
      public java.util.ArrayDeque<net.minecraft.world.level.block.RedstoneTorchBlock.Toggle> redstoneUpdateInfos; // Paper - Move from Map in BlockRedstoneTorch to here
  
@@ -68,7 +68,7 @@ index a9315b7acec3c2ccaf879e0f1d45c062d8e201b1..7dec61b831860e372f1785c2ae838cb3
      // Paper start - fix and optimise world upgrading
      // copied from below
      public static ResourceKey<DimensionType> getDimensionKey(DimensionType manager) {
-@@ -704,6 +725,7 @@ public abstract class Level implements LevelAccessor, AutoCloseable {
+@@ -706,6 +727,7 @@ public abstract class Level implements LevelAccessor, AutoCloseable {
              if (!this.preventPoiUpdated) {
                  this.onBlockStateChange(blockposition, iblockdata1, iblockdata2);
              }
@@ -76,7 +76,7 @@ index a9315b7acec3c2ccaf879e0f1d45c062d8e201b1..7dec61b831860e372f1785c2ae838cb3
              // CraftBukkit end
          }
      }
-@@ -809,8 +831,20 @@ public abstract class Level implements LevelAccessor, AutoCloseable {
+@@ -811,8 +833,20 @@ public abstract class Level implements LevelAccessor, AutoCloseable {
      public void neighborChanged(BlockPos pos, Block sourceBlock, BlockPos neighborPos) {
          if (!this.isClientSide) {
              BlockState iblockdata = this.getBlockState(pos);

patches/server/0009-Add-BlockDestroyedByNeighborEvent.patch

@@ -5,10 +5,10 @@ Subject: [PATCH] Add BlockDestroyedByNeighborEvent
 
 
 diff --git a/src/main/java/net/minecraft/world/level/Level.java b/src/main/java/net/minecraft/world/level/Level.java
-index 7dec61b831860e372f1785c2ae838cb3ad2fc623..9b704693ea8d8677d3c25d5a3c08d4ef26aa1fc3 100644
+index 46a1b0519aaccc2b5625104d42168254bfb27cd9..5e87676aa9dfa26ac052aa0c1fce35b8822e7a50 100644
 --- a/src/main/java/net/minecraft/world/level/Level.java
 +++ b/src/main/java/net/minecraft/world/level/Level.java
-@@ -747,6 +747,17 @@ public abstract class Level implements LevelAccessor, AutoCloseable {
+@@ -749,6 +749,17 @@ public abstract class Level implements LevelAccessor, AutoCloseable {
          if (iblockdata.isAir()) {
              return false;
          } else {

patches/server/0013-Packet-obfuscation-and-reduction.patch

@@ -0,0 +1,217 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Cryptite <cryptite@gmail.com>
+Date: Wed, 6 Oct 2021 11:03:01 -0500
+Subject: [PATCH] Packet obfuscation and reduction
+
+Minecraft is overzealous about packet updates for Entities. In Loka's case, we want to reduce as many unnecessary
+packet updates as possible. This patch is likely to be updated over and over in terms of reducing packet sends.
+
+In summary, this patch creates the concept of a "foreignValue" of a packet's data. We treat packets in two ways:
+1) The packet sent to the player itself (the normal way). This always has all of the values as usual.
+2) The packet data as seen by any other (foreign) players.
+
+This patch adds the ability to set a "foreignValue" for an entity value so as to obfuscate data received by other players.
+The current packets modified/obfuscated are the following:
+
+- Health - Foreign Players will only receive packets that say the player is "alive or dead (max health or 0 health).
+    -- This reduces the amount of health packet updates as well which is great for players in combat.
+
+- Air Level - Foreign players will only ever see a player as having full oxygen
+    -- Air level packets are sent PER-TICK, and as such a player with any change in air level will only spam themselves
+    with packets instead of every single player within tracking distance
+
+- Score - Foreign players will only see a player's score as 0 and will not update due to gathering xp orbs, etc.
+
+
+
+diff --git a/src/main/java/net/minecraft/network/protocol/game/ClientboundSetEntityDataPacket.java b/src/main/java/net/minecraft/network/protocol/game/ClientboundSetEntityDataPacket.java
+index 3e17f6131bf590d7c4a16b79c1c145cb4f565bc9..e1233fa58d068448d0accef7a7f6725fcb902848 100644
+--- a/src/main/java/net/minecraft/network/protocol/game/ClientboundSetEntityDataPacket.java
++++ b/src/main/java/net/minecraft/network/protocol/game/ClientboundSetEntityDataPacket.java
+@@ -22,6 +22,13 @@ public class ClientboundSetEntityDataPacket implements Packet<ClientGamePacketLi
+ 
+     }
+ 
++    // Slice start
++    public ClientboundSetEntityDataPacket(int id, List<SynchedEntityData.DataItem<?>> packedItems) {
++        this.id = id;
++        this.packedItems = packedItems;
++    }
++    // Slice end
++
+     public ClientboundSetEntityDataPacket(FriendlyByteBuf buf) {
+         this.id = buf.readVarInt();
+         this.packedItems = SynchedEntityData.unpack(buf);
+diff --git a/src/main/java/net/minecraft/network/syncher/SynchedEntityData.java b/src/main/java/net/minecraft/network/syncher/SynchedEntityData.java
+index 4df12454001f0de5f358c88d876e34c35a736c42..72c74d2369a36b14f1103aa74b096f50e7990f4d 100644
+--- a/src/main/java/net/minecraft/network/syncher/SynchedEntityData.java
++++ b/src/main/java/net/minecraft/network/syncher/SynchedEntityData.java
+@@ -136,6 +136,11 @@ public class SynchedEntityData {
+     }
+ 
+     public <T> void set(EntityDataAccessor<T> key, T value) {
++        //Slice start
++        set(key, value, null);
++    }
++
++    public <T> void set(EntityDataAccessor<T> key, T value, @Nullable T foreignValue) { // Slice end
+         SynchedEntityData.DataItem<T> datawatcher_item = this.getItem(key);
+ 
+         if (ObjectUtils.notEqual(value, datawatcher_item.getValue())) {
+@@ -145,6 +150,11 @@ public class SynchedEntityData {
+             this.isDirty = true;
+         }
+ 
++        // Slice start
++        if (foreignValue != null && ObjectUtils.notEqual(foreignValue, datawatcher_item.getForeignValue())) {
++            datawatcher_item.setForeignValue(foreignValue);
++        }
++        // Slice end
+     }
+ 
+     // CraftBukkit start - add method from above
+@@ -200,6 +210,28 @@ public class SynchedEntityData {
+         return list;
+     }
+ 
++    // Slice start
++    @Nullable
++    public List<SynchedEntityData.DataItem<?>> packForeignDirty(List<DataItem<?>> unpackedData) {
++        List<SynchedEntityData.DataItem<?>> list = null;
++
++        for (DataItem<?> dataItem : unpackedData) {
++            DataItem<?> item = itemsById.get(dataItem.accessor.getId());
++            if (item.isDirty(true)) {
++                item.setForeignDirty(false);
++
++                if (list == null) {
++                    list = Lists.newArrayList();
++                }
++
++                list.add(item.copy(true));
++            }
++        }
++
++        return list;
++    }
++    // Slice end
++
+     @Nullable
+     public List<SynchedEntityData.DataItem<?>> getAll() {
+         List<SynchedEntityData.DataItem<?>> list = null;
+@@ -313,11 +345,14 @@ public class SynchedEntityData {
+         final EntityDataAccessor<T> accessor;
+         T value;
+         private boolean dirty;
++        @Nullable T foreignValue = null; // Slice
++        private boolean foreignDirty; // Slice
+ 
+         public DataItem(EntityDataAccessor<T> data, T value) {
+             this.accessor = data;
+             this.value = value;
+             this.dirty = true;
++            this.foreignDirty = true; // Slice
+         }
+ 
+         public EntityDataAccessor<T> getAccessor() {
+@@ -343,5 +378,34 @@ public class SynchedEntityData {
+         public SynchedEntityData.DataItem<T> copy() {
+             return new SynchedEntityData.DataItem<>(this.accessor, this.accessor.getSerializer().copy(this.value));
+         }
++
++        // Slice start
++        public void setForeignValue(T foreignValue) {
++            this.foreignValue = foreignValue;
++            this.foreignDirty = true;
++        }
++
++        public @Nullable T getForeignValue() {
++            return foreignValue;
++        }
++
++        public boolean isDirty(boolean foreign) {
++            if (foreign) {
++                //There must be a foreign value in order for this to be dirty, otherwise we consider this a normal
++                //value and check the normal dirty flag.
++                return foreignValue == null || this.foreignDirty;
++            }
++
++            return this.dirty;
++        }
++
++        public void setForeignDirty(boolean dirty) {
++            this.foreignDirty = dirty;
++        }
++
++        public SynchedEntityData.DataItem<T> copy(boolean foreign) {
++            return new SynchedEntityData.DataItem<>(this.accessor, this.accessor.getSerializer().copy((foreign && this.foreignValue != null ? this.foreignValue : this.value)));
++        }
++        // Slice end
+     }
+ }
+diff --git a/src/main/java/net/minecraft/server/level/ServerEntity.java b/src/main/java/net/minecraft/server/level/ServerEntity.java
+index b7c9294fdd3d799d410afba4a1118aa371c98533..b5205bfc6f9834dc811df71bfb96494448c8dfed 100644
+--- a/src/main/java/net/minecraft/server/level/ServerEntity.java
++++ b/src/main/java/net/minecraft/server/level/ServerEntity.java
+@@ -368,7 +368,21 @@ public class ServerEntity {
+         SynchedEntityData datawatcher = this.entity.getEntityData();
+ 
+         if (datawatcher.isDirty()) {
+-            this.broadcastAndSend(new ClientboundSetEntityDataPacket(this.entity.getId(), datawatcher, false));
++            // Slice start
++            ClientboundSetEntityDataPacket dataPacket = new ClientboundSetEntityDataPacket(this.entity.getId(), datawatcher, false);
++            if (this.entity instanceof ServerPlayer serverPlayer) {
++                serverPlayer.connection.send(dataPacket);
++
++                //Get the packedData that the original packet has, and then determine if any of those are changed in
++                //the foreign version. If null, nothing to notify foreign trackers about.
++                List<SynchedEntityData.DataItem<?>> dirtyItems = datawatcher.packForeignDirty(dataPacket.getUnpackedData());
++                if (dirtyItems != null) {
++                    this.broadcast(new ClientboundSetEntityDataPacket(this.entity.getId(), dirtyItems));
++                }
++            } else {
++                this.broadcastAndSend(dataPacket);
++            }
++            // Slice end
+         }
+ 
+         if (this.entity instanceof LivingEntity) {
+diff --git a/src/main/java/net/minecraft/world/entity/Entity.java b/src/main/java/net/minecraft/world/entity/Entity.java
+index 049a9ba9cc96880513e681f7d29bd5f9681fbb0e..37836b6f9b39ab1dcbfa1e4dea90e4d12fc9e5b9 100644
+--- a/src/main/java/net/minecraft/world/entity/Entity.java
++++ b/src/main/java/net/minecraft/world/entity/Entity.java
+@@ -2944,7 +2944,7 @@ public abstract class Entity implements Nameable, EntityAccess, CommandSource, n
+         if (event.isCancelled()) {
+             return;
+         }
+-        this.entityData.set(Entity.DATA_AIR_SUPPLY_ID, event.getAmount());
++        this.entityData.set(Entity.DATA_AIR_SUPPLY_ID, event.getAmount(), getMaxAirSupply()); // Slice
+         // CraftBukkit end
+     }
+ 
+diff --git a/src/main/java/net/minecraft/world/entity/player/Player.java b/src/main/java/net/minecraft/world/entity/player/Player.java
+index 4a35056b01b947c57f7ca06c974463008fc4bbef..80a8ea35b47cc649f435856cad19a80d69da8425 100644
+--- a/src/main/java/net/minecraft/world/entity/player/Player.java
++++ b/src/main/java/net/minecraft/world/entity/player/Player.java
+@@ -633,7 +633,7 @@ public abstract class Player extends LivingEntity {
+     public void increaseScore(int score) {
+         int j = this.getScore();
+ 
+-        this.entityData.set(Player.DATA_SCORE_ID, j + score);
++        this.entityData.set(Player.DATA_SCORE_ID, j + score, 0); // Slice
+     }
+ 
+     @Override
+diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
+index c64911651f3d736c83cc83996de04920b091cc57..cf8d4edba400d5f21737c0af52a1193f69386fa9 100644
+--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
++++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
+@@ -1997,7 +1997,7 @@ public class CraftPlayer extends CraftHumanEntity implements Player {
+                 this.sendHealthUpdate();
+             }
+         }
+-        this.getHandle().getEntityData().set(LivingEntity.DATA_HEALTH_ID, (float) this.getScaledHealth());
++        this.getHandle().getEntityData().set(LivingEntity.DATA_HEALTH_ID, (float) this.getScaledHealth(), isDead() ? 0f : 20f); // Slice
+ 
+         this.getHandle().maxHealthCache = getMaxHealth();
+     }