Initial sniffer code

core/src/main/java/org/geysermc/geyser/entity/EntityDefinitions.java

@@ -133,6 +133,7 @@ public final class EntityDefinitions {
     public static final EntityDefinition<AbstractFishEntity> SALMON;
     public static final EntityDefinition<SheepEntity> SHEEP;
     public static final EntityDefinition<ShulkerEntity> SHULKER;
+    public static final EntityDefinition<SnifferEntity> SNIFFER;
     public static final EntityDefinition<ThrowableEntity> SHULKER_BULLET;
     public static final EntityDefinition<MonsterEntity> SILVERFISH;
     public static final EntityDefinition<SkeletonEntity> SKELETON;
@@ -842,6 +843,11 @@ public final class EntityDefinitions {
                     .height(1.3f).width(0.9f)
                     .addTranslator(MetadataType.BYTE, SheepEntity::setSheepFlags)
                     .build();
+            SNIFFER = EntityDefinition.inherited(SnifferEntity::new, ageableEntityBase)
+                    .type(EntityType.SNIFFER)
+                    .height(1.75f).width(1.9f)
+                    .addTranslator(MetadataType.SNIFFER_STATE, SnifferEntity::setSnifferState)
+                    .build();
             STRIDER = EntityDefinition.inherited(StriderEntity::new, ageableEntityBase)
                     .type(EntityType.STRIDER)
                     .height(1.7f).width(0.9f)

core/src/main/java/org/geysermc/geyser/entity/type/living/animal/SnifferEntity.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2019-2023 GeyserMC. http://geysermc.org
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * @author GeyserMC
+ * @link https://github.com/GeyserMC/Geyser
+ */
+
+package org.geysermc.geyser.entity.type.living.animal;
+
+import com.github.steveice10.mc.protocol.data.game.entity.metadata.SnifferState;
+import com.github.steveice10.mc.protocol.data.game.entity.metadata.type.ObjectEntityMetadata;
+import org.cloudburstmc.math.vector.Vector3f;
+import org.geysermc.geyser.entity.EntityDefinition;
+import org.geysermc.geyser.session.GeyserSession;
+
+import java.util.UUID;
+
+public class SnifferEntity extends AnimalEntity {
+    public SnifferEntity(GeyserSession session, int entityId, long geyserId, UUID uuid, EntityDefinition<?> definition, Vector3f position, Vector3f motion, float yaw, float pitch, float headYaw) {
+        super(session, entityId, geyserId, uuid, definition, position, motion, yaw, pitch, headYaw);
+    }
+
+    public void setSnifferState(ObjectEntityMetadata<SnifferState> entityMetadata) {
+
+    }
+}

core/src/main/java/org/geysermc/geyser/network/GameProtocol.java

@@ -30,6 +30,7 @@ import com.github.steveice10.mc.protocol.codec.PacketCodec;
 import org.cloudburstmc.protocol.bedrock.codec.BedrockCodec;
 import org.cloudburstmc.protocol.bedrock.codec.v582.Bedrock_v582;
 import org.cloudburstmc.protocol.bedrock.netty.codec.packet.BedrockPacketCodec;
+import org.geysermc.geyser.session.GeyserSession;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -77,6 +78,12 @@ public final class GameProtocol {
         return null;
     }
 
+    /* Bedrock convenience methods to gatekeep features and easily remove the check on version removal */
+
+    public static boolean isPre1_20(GeyserSession session) {
+        return session.getUpstream().getProtocolVersion() >= Bedrock_v582.CODEC.getProtocolVersion();
+    }
+
     /**
      * Gets the {@link PacketCodec} for Minecraft: Java Edition.
      *

core/src/main/java/org/geysermc/geyser/network/GeyserServerInitializer.java

@@ -47,11 +47,6 @@ public class GeyserServerInitializer extends BedrockServerInitializer {
         this.geyser = geyser;
     }
 
-    @Override
-    protected void postInitChannel(Channel channel) throws Exception {
-        super.postInitChannel(channel);
-    }
-
     @Override
     public void initSession(@Nonnull BedrockServerSession bedrockServerSession) {
         try {

core/src/main/java/org/geysermc/geyser/network/UpstreamPacketHandler.java

@@ -225,6 +225,11 @@ public class UpstreamPacketHandler extends LoggingPacketHandler {
                     stackPacket.getExperiments().add(new ExperimentData("data_driven_items", true));
                 }
 
+                if (GameProtocol.isPre1_20(session)) {
+                    stackPacket.getExperiments().add(new ExperimentData("next_major_update", true));
+                    stackPacket.getExperiments().add(new ExperimentData("sniffer", true));
+                }
+
                 session.sendUpstreamPacket(stackPacket);
                 break;
 

core/src/main/java/org/geysermc/geyser/session/GeyserSession.java

@@ -124,6 +124,7 @@ import org.geysermc.geyser.item.Items;
 import org.geysermc.geyser.level.JavaDimension;
 import org.geysermc.geyser.level.WorldManager;
 import org.geysermc.geyser.level.physics.CollisionManager;
+import org.geysermc.geyser.network.GameProtocol;
 import org.geysermc.geyser.network.netty.LocalSession;
 import org.geysermc.geyser.registry.Registries;
 import org.geysermc.geyser.registry.type.BlockMappings;
@@ -1540,6 +1541,11 @@ public class GeyserSession implements GeyserConnection, GeyserCommandSource {
         startGamePacket.setRewindHistorySize(0);
         startGamePacket.setServerAuthoritativeBlockBreaking(false);
 
+        if (GameProtocol.isPre1_20(this)) {
+            startGamePacket.getExperiments().add(new ExperimentData("next_major_update", true));
+            startGamePacket.getExperiments().add(new ExperimentData("sniffer", true));
+        }
+
         upstream.sendPacket(startGamePacket);
     }