Refactor and improve movement-related packets, fix keep alive

README.md

@@ -1,5 +1,16 @@
 # Uranos
 
+Uranos is a game server implementing the Minecraft protocol. That means you can use the official Minecraft client to
+join Uranos servers.
+
+Its goal is to be a modern alternative to Bukkit, SpigotMC and Paper. It is primarily intended to make creating custom
+games inside of Minecraft easier than it is possible with the existing alternatives, but it can also be used for
+something like a lobby/hub server.
+
+The most important thing for Uranos is
+[developer experience (DX)](https://medium.com/swlh/what-is-dx-developer-experience-401a0e44a9d9). After that comes
+performance.
+
 ## Milestones
 
 - Players can see entities
@@ -19,6 +30,7 @@
 - Entity AI framework
 - Scoreboards + Teams
 - Crafting
+- Rate limiting packets
 
 ## Development
 

test-plugin/src/main/kotlin/space/uranos/testplugin/TestPlugin.kt

@@ -13,6 +13,7 @@ import space.uranos.entity.CowEntity
 import space.uranos.net.ServerListInfo
 import space.uranos.net.event.ServerListInfoRequestEvent
 import space.uranos.net.event.SessionAfterLoginEvent
+import space.uranos.net.packet.play.EntityHeadYawPacket
 import space.uranos.player.GameMode
 import space.uranos.plugin.Plugin
 import space.uranos.testplugin.anvil.AnvilWorld
@@ -22,8 +23,10 @@ import space.uranos.util.secondsToTicks
 import space.uranos.world.*
 import space.uranos.world.block.GreenWoolBlock
 import space.uranos.world.block.RedWoolBlock
+import kotlin.random.Random
+import kotlin.random.nextUBytes
 
-class TestPlugin: Plugin("Test", "1.0.0") {
+class TestPlugin : Plugin("Test", "1.0.0") {
     override suspend fun onEnable() {
         val dimension = Dimension(
             "test:test",
@@ -83,9 +86,18 @@ class TestPlugin: Plugin("Test", "1.0.0") {
         }
 
         var x = 1.0
-        Uranos.scheduler.executeRepeating(1) {
+        Uranos.scheduler.executeRepeating(20) {
             x += 0.2
-            runInServerThread { entity.position = Position(x + 0.5, x, 0.5, 0f, 0f) }
+            runInServerThread {
+                Uranos.players.forEach {
+                    it.session.send(
+                        EntityHeadYawPacket(
+                            entity.numericID,
+                            Random.nextUBytes(1)[0]
+                        )
+                    )
+                }
+            }
             if (x >= 10.0) x = 0.0
         }
     }

uranos-api/src/main/kotlin/space/uranos/Position.kt

@@ -7,16 +7,15 @@ package space.uranos
 
 import space.uranos.world.VoxelLocation
 import space.uranos.world.World
-import java.lang.IllegalArgumentException
 import kotlin.math.roundToInt
 
 /**
  * A combination of x, y and z coordinates and an orientation (yaw and pitch).
  *
  * @param yaw The yaw rotation in degrees. Must be in `[0; 360[`.
- * @param pitch The pitch rotation as a value between -90 (up) and 90 (down).
+ * @param headPitch The pitch rotation of the head as a value between -90 (up) and 90 (down).
  */
-data class Position(val x: Double, val y: Double, val z: Double, val yaw: Float, val pitch: Float) {
+data class Position(val x: Double, val y: Double, val z: Double, val yaw: Float, val headPitch: Float) {
     init {
         if (yaw >= 360) throw IllegalArgumentException("yaw must be lower than 360")
         if (yaw < 0) throw IllegalArgumentException("yaw must not be negative")
@@ -38,8 +37,8 @@ data class Position(val x: Double, val y: Double, val z: Double, val yaw: Float,
     fun toVector() = Vector(x, y, z)
     infix fun inside(world: World): Pair<World, Position> = world to this
 
-    val yawIn256Steps get() = ((yaw / 360) * 256).toInt().toUByte()
+    val yawIn256Steps: UByte get() = ((yaw / 360) * 256).toInt().toUByte()
-    val pitchIn256Steps get() = ((yaw / 360) * 256).toInt().toUByte()
+    val headPitchIn256Steps: UByte get() = ((yaw / 360) * 256).toInt().toUByte()
 
     operator fun get(part: CoordinatePart): Double = when (part) {
         CoordinatePart.X -> x

uranos-api/src/main/kotlin/space/uranos/net/Session.kt

@@ -18,7 +18,7 @@ import space.uranos.player.GameMode
 import space.uranos.player.Player
 import space.uranos.world.World
 import java.net.InetAddress
-import java.util.*
+import java.util.UUID
 
 abstract class Session {
     val events by lazy { EventBusWrapper<Session>(this) }
@@ -114,14 +114,14 @@ abstract class Session {
     )
 
     /**
-     * Sends a packet.
+     * Sends a packet instantly.
      */
-    abstract suspend fun send(packet: OutgoingPacket)
+    abstract suspend fun sendNow(packet: OutgoingPacket)
 
     /**
-     * Sends a packet the next tick.
+     * Adds packet to the queue.
      */
-    abstract fun sendNextTick(packet: OutgoingPacket)
+    abstract fun send(packet: OutgoingPacket)
 
     /**
      * Sends a plugin message packet.

uranos-api/src/main/kotlin/space/uranos/util/MemoizedDelegate.kt

@@ -7,14 +7,14 @@ package space.uranos.util
 
 import kotlin.reflect.KProperty
 
-class MemoizedDelegate<T>(private val dependingGetter: () -> Any?, private val initializer: () -> T) {
+class MemoizedDelegate<T>(private val key: () -> Any?, private val initializer: () -> T) {
     private object UNINITIALIZED
 
     private var lastDependingValue: Any? = null
     private var value: Any? = UNINITIALIZED
 
     operator fun getValue(thisRef: Any?, property: KProperty<*>): T {
-        val currentDependingValue = dependingGetter()
+        val currentDependingValue = key()
 
         if (value == UNINITIALIZED || (lastDependingValue != currentDependingValue)) {
             value = initializer()

uranos-api/src/main/kotlin/space/uranos/world/VoxelLocation.kt

@@ -17,7 +17,7 @@ import space.uranos.Vector
  */
 data class VoxelLocation(val x: Int, val y: UByte, val z: Int) {
     /**
-     * Converts this VoxelLocation to a
+     * Converts this VoxelLocation to a Location.
      */
     fun asLocation(): Location = Location(x.toDouble(), y.toDouble(), z.toDouble())
 

uranos-packet-codecs/src/main/kotlin/space/uranos/net/packet/play/EntityHeadPitchPacketCodec.kt

@@ -9,11 +9,11 @@ import io.netty.buffer.ByteBuf
 import space.uranos.net.MinecraftProtocolDataTypes.writeVarInt
 import space.uranos.net.packet.OutgoingPacketCodec
 
-object EntityOrientationPacketCodec :
+object EntityHeadPitchPacketCodec :
-    OutgoingPacketCodec<EntityOrientationPacket>(0x29, EntityOrientationPacket::class) {
+    OutgoingPacketCodec<EntityHeadPitchPacket>(0x29, EntityHeadPitchPacket::class) {
-    override fun EntityOrientationPacket.encode(dst: ByteBuf) {
+    override fun EntityHeadPitchPacket.encode(dst: ByteBuf) {
         dst.writeVarInt(entityID)
-        dst.writeByte(yaw.toInt())
+        dst.writeByte(0) // Should be yaw, but is actually ignored. Use EntityHeadYawPacket instead.
         dst.writeByte(pitch.toInt())
         dst.writeBoolean(onGround)
     }

uranos-packet-codecs/src/main/kotlin/space/uranos/net/packet/play/EntityHeadYawPacketCodec.kt

@@ -0,0 +1,17 @@
+/*
+ * Copyright 2020-2021 Moritz Ruth and Uranos contributors
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file
+ */
+
+package space.uranos.net.packet.play
+
+import io.netty.buffer.ByteBuf
+import space.uranos.net.MinecraftProtocolDataTypes.writeVarInt
+import space.uranos.net.packet.OutgoingPacketCodec
+
+object EntityHeadYawPacketCodec : OutgoingPacketCodec<EntityHeadYawPacket>(0x3A, EntityHeadYawPacket::class) {
+    override fun EntityHeadYawPacket.encode(dst: ByteBuf) {
+        dst.writeVarInt(entityID)
+        dst.writeByte(yaw.toInt())
+    }
+}

uranos-packet-codecs/src/main/kotlin/space/uranos/net/packet/play/EntityRelativeMoveWithOrientationPacketCodec.kt

@@ -17,7 +17,7 @@ object EntityRelativeMoveWithOrientationPacketCodec :
         dst.writeShort(deltaY.toInt())
         dst.writeShort(deltaZ.toInt())
         dst.writeByte(yaw.toInt())
-        dst.writeByte(pitch.toInt())
+        dst.writeByte(headPitch.toInt())
         dst.writeBoolean(onGround)
     }
 }

uranos-packet-codecs/src/main/kotlin/space/uranos/net/packet/play/EntityTeleportPacketCodec.kt

@@ -13,11 +13,11 @@ object EntityTeleportPacketCodec :
     OutgoingPacketCodec<EntityTeleportPacket>(0x56, EntityTeleportPacket::class) {
     override fun EntityTeleportPacket.encode(dst: ByteBuf) {
         dst.writeVarInt(entityID)
-        dst.writeDouble(position.x)
+        dst.writeDouble(x)
-        dst.writeDouble(position.y)
+        dst.writeDouble(y)
-        dst.writeDouble(position.z)
+        dst.writeDouble(z)
-        dst.writeByte(position.yawIn256Steps.toInt())
+        dst.writeByte(yaw.toInt())
-        dst.writeByte(position.pitchIn256Steps.toInt())
+        dst.writeByte(headPitch.toInt())
         dst.writeBoolean(onGround)
     }
 }

uranos-packet-codecs/src/main/kotlin/space/uranos/net/packet/play/OutgoingPlayerPositionPacketCodec.kt

@@ -17,7 +17,7 @@ object OutgoingPlayerPositionPacketCodec :
         dst.writeDouble(position.y)
         dst.writeDouble(position.z)
         dst.writeFloat(position.yaw)
-        dst.writeFloat(position.pitch)
+        dst.writeFloat(position.headPitch)
         dst.writeByte(bitmask(relativeX, relativeY, relativeZ, relativeYaw, relativePitch))
         dst.writeVarInt(0) // Teleport ID, I am not sure why this is needed
     }

uranos-packet-codecs/src/main/kotlin/space/uranos/net/packet/play/PlayProtocol.kt

@@ -18,7 +18,8 @@ object PlayProtocol : Protocol(
     DeclareRecipesPacketCodec,
     DestroyEntitiesPacketCodec,
     DisconnectPacketCodec,
-    EntityOrientationPacketCodec,
+    EntityHeadPitchPacketCodec,
+    EntityHeadYawPacketCodec,
     EntityRelativeMovePacketCodec,
     EntityRelativeMoveWithOrientationPacketCodec,
     EntityTeleportPacketCodec,
@@ -40,5 +41,5 @@ object PlayProtocol : Protocol(
     SpawnObjectEntityPacketCodec,
     SpawnPaintingPacketCodec,
     TagsPacketCodec,
-    UpdateViewPositionPacketCodec
+    ViewPositionPacketCodec
 )

uranos-packet-codecs/src/main/kotlin/space/uranos/net/packet/play/SpawnLivingEntityPacketCodec.kt

@@ -20,7 +20,7 @@ object SpawnLivingEntityPacketCodec : OutgoingPacketCodec<SpawnLivingEntityPacke
         dst.writeDouble(position.y)
         dst.writeDouble(position.z)
         dst.writeByte(position.yawIn256Steps.toInt())
-        dst.writeByte(position.pitchIn256Steps.toInt())
+        dst.writeByte(position.headPitchIn256Steps.toInt())
         dst.writeByte(0) // Head pitch; I do not know what this does
         dst.writeShort((velocity.x * 8000).toInt().toShort().toInt())
         dst.writeShort((velocity.y * 8000).toInt().toShort().toInt())

uranos-packet-codecs/src/main/kotlin/space/uranos/net/packet/play/SpawnObjectEntityPacketCodec.kt

@@ -20,7 +20,7 @@ object SpawnObjectEntityPacketCodec : OutgoingPacketCodec<SpawnObjectEntityPacke
         dst.writeDouble(position.y)
         dst.writeDouble(position.z)
         dst.writeByte(position.yawIn256Steps.toInt())
-        dst.writeByte(position.pitchIn256Steps.toInt())
+        dst.writeByte(position.headPitchIn256Steps.toInt())
         dst.writeInt(data)
         dst.writeShort((velocity.x * 8000).toInt().toShort().toInt())
         dst.writeShort((velocity.y * 8000).toInt().toShort().toInt())

uranos-packet-codecs/src/main/kotlin/space/uranos/net/packet/play/ViewPositionPacketCodec.kt

@@ -9,9 +9,9 @@ import io.netty.buffer.ByteBuf
 import space.uranos.net.MinecraftProtocolDataTypes.writeVarInt
 import space.uranos.net.packet.OutgoingPacketCodec
 
-object UpdateViewPositionPacketCodec :
+object ViewPositionPacketCodec :
-    OutgoingPacketCodec<UpdateViewPositionPacket>(0x40, UpdateViewPositionPacket::class) {
+    OutgoingPacketCodec<ViewPositionPacket>(0x40, ViewPositionPacket::class) {
-    override fun UpdateViewPositionPacket.encode(dst: ByteBuf) {
+    override fun ViewPositionPacket.encode(dst: ByteBuf) {
         dst.writeVarInt(chunkKey.x)
         dst.writeVarInt(chunkKey.z)
     }

uranos-packets/src/main/kotlin/space/uranos/net/packet/play/EntityHeadPitchPacket.kt

@@ -7,9 +7,8 @@ package space.uranos.net.packet.play
 
 import space.uranos.net.packet.OutgoingPacket
 
-data class EntityOrientationPacket(
+data class EntityHeadPitchPacket(
     val entityID: Int,
-    val yaw: UByte,
     val pitch: UByte,
     val onGround: Boolean
 ) : OutgoingPacket()

uranos-packets/src/main/kotlin/space/uranos/net/packet/play/EntityHeadYawPacket.kt

@@ -0,0 +1,13 @@
+/*
+ * Copyright 2020-2021 Moritz Ruth and Uranos contributors
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file
+ */
+
+package space.uranos.net.packet.play
+
+import space.uranos.net.packet.OutgoingPacket
+
+data class EntityHeadYawPacket(
+    val entityID: Int,
+    val yaw: UByte
+) : OutgoingPacket()

uranos-packets/src/main/kotlin/space/uranos/net/packet/play/EntityRelativeMoveWithOrientationPacket.kt

@@ -19,6 +19,6 @@ data class EntityRelativeMoveWithOrientationPacket(
     /**
      * Absolute value.
      */
-    val pitch: UByte,
+    val headPitch: UByte,
     val onGround: Boolean
 ) : OutgoingPacket()

uranos-packets/src/main/kotlin/space/uranos/net/packet/play/EntityTeleportPacket.kt

@@ -10,6 +10,20 @@ import space.uranos.net.packet.OutgoingPacket
 
 data class EntityTeleportPacket(
     val entityID: Int,
-    val position: Position,
+    val x: Double,
+    val y: Double,
+    val z: Double,
+    val yaw: UByte,
+    val headPitch: UByte,
     val onGround: Boolean
-) : OutgoingPacket()
+) : OutgoingPacket() {
+    constructor(entityID: Int, position: Position, onGround: Boolean) : this(
+        entityID,
+        position.x,
+        position.y,
+        position.z,
+        position.yawIn256Steps,
+        position.headPitchIn256Steps,
+        onGround
+    )
+}

uranos-packets/src/main/kotlin/space/uranos/net/packet/play/ViewPositionPacket.kt

@@ -12,4 +12,4 @@ import space.uranos.world.Chunk
  * The reason why this packet exists and what it does is not clear at the moment of writing.
  * It it sent every time the player crosses a chunk or chunk section border.
  */
-data class UpdateViewPositionPacket(val chunkKey: Chunk.Key) : OutgoingPacket()
+data class ViewPositionPacket(val chunkKey: Chunk.Key) : OutgoingPacket()

uranos-packets/src/main/kotlin/space/uranos/util/CreateEntityMovementPacket.kt

@@ -8,21 +8,20 @@ package space.uranos.util
 import space.uranos.Position
 import space.uranos.abs
 import space.uranos.net.packet.OutgoingPacket
-import space.uranos.net.packet.play.EntityOrientationPacket
+import space.uranos.net.packet.play.EntityHeadPitchPacket
 import space.uranos.net.packet.play.EntityRelativeMovePacket
 import space.uranos.net.packet.play.EntityRelativeMoveWithOrientationPacket
 import space.uranos.net.packet.play.EntityTeleportPacket
 
 fun createEntityMovementPacket(entityID: Int, oldPosition: Position, newPosition: Position): OutgoingPacket? {
     val delta = abs(newPosition.toVector() - oldPosition.toVector())
-    val orientationChanged = oldPosition.yaw != newPosition.yaw || oldPosition.pitch != newPosition.pitch
+    val orientationChanged = oldPosition.yaw != newPosition.yaw || oldPosition.headPitch != newPosition.headPitch
     val onGround = true // TODO: Find out what onGround does
 
     return if (delta.x + delta.y + delta.z == 0.0) {
-        if (orientationChanged) EntityOrientationPacket(
+        if (orientationChanged) EntityHeadPitchPacket(
             entityID,
-            newPosition.yawIn256Steps,
+            newPosition.headPitchIn256Steps,
-            newPosition.pitchIn256Steps,
             onGround
         ) else null
     } else if (delta.x > 8 || delta.y > 8 || delta.z > 8) {
@@ -34,7 +33,7 @@ fun createEntityMovementPacket(entityID: Int, oldPosition: Position, newPosition
             getDeltaShort(delta.y),
             getDeltaShort(delta.z),
             newPosition.yawIn256Steps,
-            newPosition.pitchIn256Steps,
+            newPosition.headPitchIn256Steps,
             onGround
         ) else EntityRelativeMovePacket(
             entityID,

uranos-server/src/main/kotlin/space/uranos/UranosScheduler.kt

@@ -10,9 +10,8 @@ import kotlinx.coroutines.runBlocking
 import kotlinx.coroutines.suspendCancellableCoroutine
 import space.uranos.logging.Logger
 import space.uranos.server.Server
-import java.util.*
+import java.util.Collections
 import java.util.concurrent.*
-import kotlin.collections.LinkedHashSet
 import kotlin.coroutines.resume
 
 /**
@@ -35,6 +34,8 @@ class UranosScheduler : Scheduler {
         @Volatile
         var cancelled: Boolean = false
 
+        val creationStackTrace = Thread.currentThread().stackTrace
+
         override fun cancel() {
             tasks.remove(this)
             cancelled = true

uranos-server/src/main/kotlin/space/uranos/UranosServer.kt

@@ -133,22 +133,28 @@ class UranosServer internal constructor() : Server() {
     }
 
     private fun startTicking() {
+        var index = 0
         scheduler.executeRepeating(1, 0) {
             runInServerThread {
                 players.forEach { it.container.tick() }
                 internalEntities.forEach { it.tick() }
-                sessions.forEach { it.packetsAdapter.tick() }
+                sessions.forEach { it.tick(index) }
             }
+
+            index++
         }
     }
 
     private fun startPingSync() {
+        // Not in UranosSession.tick because this simplifies reusing the packet and the ping is not a critical information
         scheduler.executeRepeating(msToTicks(config.pingUpdateInterval.toMillis()), 0) {
             val packet = PlayerInfoPacket(
                 PlayerInfoPacket.Action.UpdateLatency(players.map { it.uuid to it.session.ping }.toMap())
             )
 
-            players.forEach { it.session.send(packet) }
+            players.forEach {
+                it.session.send(packet)
+            }
         }
     }
 
@@ -156,8 +162,8 @@ class UranosServer internal constructor() : Server() {
         eventBus.on<ViewingChangedEvent>(EventHandlerPosition.LAST) { event ->
             if (event.target == event.player.entity) return@on
 
-            if (event.viewing) event.player.session.sendNextTick(event.target.createSpawnPacket())
+            if (event.viewing) event.player.session.send(event.target.createSpawnPacket())
-            else event.player.session.sendNextTick(DestroyEntitiesPacket(arrayOf(event.target.numericID)))
+            else event.player.session.send(DestroyEntitiesPacket(arrayOf(event.target.numericID)))
         }
     }
 

uranos-server/src/main/kotlin/space/uranos/entity/UranosEntity.kt

@@ -69,7 +69,7 @@ sealed class UranosEntity(server: UranosServer) : Entity {
         }
     }
 
-    suspend fun tick() {
+    open suspend fun tick() {
         container.tick()
     }
 }
@@ -81,7 +81,7 @@ abstract class UranosLivingEntity(server: UranosServer) : UranosEntity(server),
     override var position: Position by container.ifChanged(Position.ZERO) { value ->
         if (viewers.isNotEmpty()) createEntityMovementPacket(numericID, lastSentPosition, value)?.let {
             for (viewer in viewers) {
-                viewer.session.sendNextTick(it)
+                viewer.session.send(it)
             }
         }
 
@@ -98,7 +98,7 @@ abstract class UranosObjectEntity(server: UranosServer) : UranosEntity(server),
     override var position: Position by container.ifChanged(Position.ZERO) { value ->
         createEntityMovementPacket(numericID, lastSentPosition, value)?.let {
             for (viewer in viewers) {
-                viewer.session.sendNextTick(it)
+                viewer.session.send(it)
             }
         }
     }

uranos-server/src/main/kotlin/space/uranos/net/LoginAndJoinProcedure.kt

@@ -22,7 +22,7 @@ import space.uranos.util.AuthenticationHelper
 import space.uranos.util.EncryptionUtils
 import space.uranos.world.Chunk
 import java.security.MessageDigest
-import java.util.*
+import java.util.UUID
 import javax.crypto.Cipher
 import javax.crypto.spec.SecretKeySpec
 
@@ -35,10 +35,10 @@ class LoginAndJoinProcedure(val session: UranosSession) {
         if (session.server.config.authenticateAndEncrypt) {
             val verifyToken = EncryptionUtils.generateVerifyToken()
             session.state = Session.State.WaitingForEncryptionVerification(packet.username, verifyToken)
-            session.send(EncryptionRequestPacket(session.server.x509EncodedPublicKey, verifyToken))
+            session.sendNow(EncryptionRequestPacket(session.server.x509EncodedPublicKey, verifyToken))
         } else {
             val uuid = UUID.nameUUIDFromBytes("OfflinePlayer:${packet.username}".toByteArray())
-            session.send(LoginSuccessPacket(uuid, packet.username))
+            session.sendNow(LoginSuccessPacket(uuid, packet.username))
             session.state = Session.State.LoginSucceeded(packet.username, uuid)
             afterLogin()
         }
@@ -71,10 +71,10 @@ class LoginAndJoinProcedure(val session: UranosSession) {
 
         val result = AuthenticationHelper.authenticate(hashString, state.username)
 
-        session.send(SetCompressionPacket(session.server.config.packetCompressionThreshold))
+        session.sendNow(SetCompressionPacket(session.server.config.packetCompressionThreshold))
         session.enableCompressionCodec()
 
-        session.send(LoginSuccessPacket(result.uuid, result.username))
+        session.sendNow(LoginSuccessPacket(result.uuid, result.username))
         session.state = Session.State.LoginSucceeded(result.username, result.uuid)
         afterLogin()
     }
@@ -93,7 +93,7 @@ class LoginAndJoinProcedure(val session: UranosSession) {
                 session.disconnect(internalReason = "No spawn location set")
             }
             else -> {
-                session.send(
+                session.sendNow(
                     JoinGamePacket(
                         0,
                         event.gameMode,
@@ -111,9 +111,9 @@ class LoginAndJoinProcedure(val session: UranosSession) {
                 )
 
                 // As this is only visual, there is no way of changing it aside from intercepting the packet.
-                session.send(ServerDifficultyPacket(DifficultySettings(Difficulty.NORMAL, false)))
+                session.sendNow(ServerDifficultyPacket(DifficultySettings(Difficulty.NORMAL, false)))
 
-                session.send(
+                session.sendNow(
                     PlayerAbilitiesPacket(
                         event.invulnerable,
                         event.flying,
@@ -174,17 +174,17 @@ class LoginAndJoinProcedure(val session: UranosSession) {
 
         session.state = Session.State.Joining(player)
 
-        session.send(SelectedHotbarSlotPacket(state.selectedHotbarSlot))
+        session.sendNow(SelectedHotbarSlotPacket(state.selectedHotbarSlot))
 
-        session.send(DeclareRecipesPacket(session.server.recipeRegistry.items.values))
+        session.sendNow(DeclareRecipesPacket(session.server.recipeRegistry.items.values))
-        session.send(tagsPacket)
+        session.sendNow(tagsPacket)
 
 //        session.send(DeclareCommandsPacket(session.server.commandRegistry.items.values))
         // UnlockRecipes
 
-        session.send(OutgoingPlayerPositionPacket(state.position))
+        session.sendNow(OutgoingPlayerPositionPacket(state.position))
 
-        session.send(PlayerInfoPacket(PlayerInfoPacket.Action.AddPlayer((session.server.players + player).map {
+        session.sendNow(PlayerInfoPacket(PlayerInfoPacket.Action.AddPlayer((session.server.players + player).map {
             it.uuid to PlayerInfoPacket.Action.AddPlayer.Data(
                 it.name,
                 it.gameMode,
@@ -194,7 +194,7 @@ class LoginAndJoinProcedure(val session: UranosSession) {
             )
         }.toMap())))
 
-        session.send(
+        session.sendNow(
             PlayerInfoPacket(
                 PlayerInfoPacket.Action.UpdateLatency(
                     session.server.players.map { it.uuid to it.session.ping }.toMap()
@@ -202,14 +202,14 @@ class LoginAndJoinProcedure(val session: UranosSession) {
             )
         )
 
-        session.send(UpdateViewPositionPacket(Chunk.Key.from(player.entity.position.toVoxelLocation())))
+        session.sendNow(ViewPositionPacket(Chunk.Key.from(player.entity.position.toVoxelLocation())))
 
-        session.scheduleKeepAlivePacket(true)
+        session.sendKeepAlivePacket()
 
         player.spawnInitially(state.world)
         session.state = Session.State.Playing(player)
 
         // WorldBorder
-        session.sendNextTick(CompassTargetPacket(player.compassTarget))
+        session.send(CompassTargetPacket(player.compassTarget))
     }
 }

uranos-server/src/main/kotlin/space/uranos/net/PacketsAdapter.kt

@@ -37,7 +37,7 @@ class PacketsAdapter(val session: UranosSession) {
     }
 
     private suspend fun handlePacket(packet: IncomingPacket) {
-        if (session.server.config.logging.shouldLog(packet)) session.logger.trace { "Packet received: $packet" }
+        if (session.server.config.logging.shouldLog(packet)) session.logger.info { "Packet received: $packet" }
 
         session.server.eventBus.emit(PacketReceivedEvent(session, packet)).ifNotCancelled {
             try {
@@ -70,7 +70,7 @@ class PacketsAdapter(val session: UranosSession) {
     }
 
     suspend fun send(packet: OutgoingPacket) {
-        if (session.server.config.logging.shouldLog(packet)) session.logger.trace { "Sending packet: $packet" }
+        if (session.server.config.logging.shouldLog(packet)) session.logger.info { "Sending packet: $packet" }
 
         session.server.eventBus.emit(PacketSendEvent(session, packet)).ifNotCancelled {
             try {
@@ -118,6 +118,7 @@ class PacketsAdapter(val session: UranosSession) {
                 session.logger warn "$message. This will cause the client to disconnect in production mode."
             else session.failAndDisconnectBecauseOfClient(message)
 
+            ReferenceCountUtil.release(data)
             return
         }
 

uranos-server/src/main/kotlin/space/uranos/net/UranosSession.kt

@@ -23,10 +23,10 @@ import space.uranos.net.packet.play.PlayProtocol
 import space.uranos.net.packet.play.PlayerInfoPacket
 import space.uranos.net.packet.status.StatusProtocol
 import space.uranos.server.event.SessionInitializedEvent
+import space.uranos.util.msToTicks
 import java.net.InetAddress
 import java.net.InetSocketAddress
 import javax.crypto.SecretKey
-import kotlin.properties.Delegates
 
 class UranosSession(val channel: io.netty.channel.Channel, val server: UranosServer) : Session() {
     override val address: InetAddress = (channel.remoteAddress() as InetSocketAddress).address
@@ -38,9 +38,13 @@ class UranosSession(val channel: io.netty.channel.Channel, val server: UranosSer
 
     override var ping: Int = -1
         set(value) {
-            if (field == -1) {
+            val player = earlyPlayer
-                val packet =
+
-                    PlayerInfoPacket(PlayerInfoPacket.Action.UpdateLatency(mapOf((state as State.WithPlayer).player.uuid to value)))
+            if (player != null && field == -1) {
+                val packet = PlayerInfoPacket(
+                    PlayerInfoPacket.Action.UpdateLatency(mapOf(player.uuid to value))
+                )
+
                 scope.launch { server.players.forEach { it.session.send(packet) } }
             }
 
@@ -71,12 +75,12 @@ class UranosSession(val channel: io.netty.channel.Channel, val server: UranosSer
 
     val packetsAdapter = PacketsAdapter(this)
 
-    override suspend fun send(packet: OutgoingPacket) = packetsAdapter.send(packet)
+    override suspend fun sendNow(packet: OutgoingPacket) = packetsAdapter.send(packet)
-    override fun sendNextTick(packet: OutgoingPacket) = packetsAdapter.sendNextTick(packet)
+    override fun send(packet: OutgoingPacket) = packetsAdapter.sendNextTick(packet)
 
     override suspend fun sendPluginMessage(channel: String, data: ByteBuf) {
         if (this.currentProtocol != PlayProtocol) throw IllegalStateException("The session is not using the PLAY protocol")
-        send(OutgoingPluginMessagePacket(channel, data))
+        sendNow(OutgoingPluginMessagePacket(channel, data))
         data.release()
     }
 
@@ -99,8 +103,8 @@ class UranosSession(val channel: io.netty.channel.Channel, val server: UranosSer
             } else reason
 
             when (currentProtocol) {
-                LoginProtocol -> send(space.uranos.net.packet.login.DisconnectPacket(finalReason))
+                LoginProtocol -> sendNow(space.uranos.net.packet.login.DisconnectPacket(finalReason))
-                PlayProtocol -> send(space.uranos.net.packet.play.DisconnectPacket(finalReason))
+                PlayProtocol -> sendNow(space.uranos.net.packet.play.DisconnectPacket(finalReason))
             }
         } else logger trace "Disconnected"
 
@@ -110,30 +114,6 @@ class UranosSession(val channel: io.netty.channel.Channel, val server: UranosSer
 
     val joinProcedure = LoginAndJoinProcedure(this)
 
-    var lastKeepAlivePacketTimestamp by Delegates.notNull<Long>()
-    lateinit var keepAliveDisconnectJob: Job
-
-    fun scheduleKeepAlivePacket(isFirst: Boolean = false) {
-        scope.launch { // TODO: Fix random disconnects (maybe some response packets are skipped?)
-            if (!isFirst) {
-                val timeSinceLastPacket = (System.currentTimeMillis() - lastKeepAlivePacketTimestamp).toInt()
-                delay(KEEP_ALIVE_PACKET_INTERVAL.toLong() - timeSinceLastPacket)
-            }
-
-            lastKeepAlivePacketTimestamp = System.currentTimeMillis()
-            send(OutgoingKeepAlivePacket(lastKeepAlivePacketTimestamp))
-
-            keepAliveDisconnectJob = launch {
-                delay(server.config.timeout.toMillis())
-                disconnect(
-                    TextComponent of "Timed out",
-                    "The client did not respond to the KeepAlive packet for " +
-                            "${server.config.timeout.toMillis()}ms"
-                )
-            }
-        }
-    }
-
     fun onConnect() = scope.launch {
         logger trace "Connected"
         packetsAdapter.launchPacketDataChannelConsumer()
@@ -147,7 +127,7 @@ class UranosSession(val channel: io.netty.channel.Channel, val server: UranosSer
         scope.launch {
             if (state == State.Disconnected) return@launch
             if (!expected && currentProtocol != HandshakingProtocol && currentProtocol != StatusProtocol)
-                logger trace "The client disconnected unexpectedly" // TODO: This is sometimes logged multiple times
+                logger trace "The client disconnected unexpectedly"
 
             packetsAdapter.stopProcessingIncomingPackets()
             coroutineContext.cancel(DisconnectedCancellationException())
@@ -192,7 +172,15 @@ class UranosSession(val channel: io.netty.channel.Channel, val server: UranosSer
             .addAfter("framing", "compression", CompressionCodec(server.config.packetCompressionThreshold))
     }
 
+    fun sendKeepAlivePacket() = send(OutgoingKeepAlivePacket(System.currentTimeMillis()))
+
+    suspend fun tick(index: Int) {
+        if (earlyPlayer != null && index % KEEP_ALIVE_PACKET_INTERVAL == 0L) sendKeepAlivePacket()
+
+        packetsAdapter.tick()
+    }
+
     companion object {
-        const val KEEP_ALIVE_PACKET_INTERVAL = 1000
+        val KEEP_ALIVE_PACKET_INTERVAL = msToTicks(1000)
     }
 }

uranos-server/src/main/kotlin/space/uranos/net/packet/play/IncomingKeepAlivePacketHandler.kt

@@ -5,17 +5,15 @@
 
 package space.uranos.net.packet.play
 
+import space.uranos.chat.TextComponent
 import space.uranos.net.PacketReceivedEventHandler
 import space.uranos.net.UranosSession
 
 object IncomingKeepAlivePacketHandler : PacketReceivedEventHandler<IncomingKeepAlivePacket>() {
     override suspend fun handle(session: UranosSession, packet: IncomingKeepAlivePacket) {
-        if (session.lastKeepAlivePacketTimestamp == packet.id) {
+        val ping = (System.currentTimeMillis() - packet.id).toInt()
-            session.ping = (System.currentTimeMillis() - session.lastKeepAlivePacketTimestamp).toInt()
+
-            session.keepAliveDisconnectJob.cancel()
+        if (ping >= session.server.config.timeout.toMillis()) session.disconnect(TextComponent of "Timed out")
-            session.scheduleKeepAlivePacket()
+        else session.ping = ping
-        } else {
-            session.disconnect(internalReason = "The ID of the last IncomingKeepAlive packet does not match the expected one.")
-        }
     }
 }

uranos-server/src/main/kotlin/space/uranos/net/packet/play/PlayerOrientationPacketHandler.kt

@@ -10,7 +10,7 @@ import space.uranos.net.UranosSession
 
 object PlayerOrientationPacketHandler : PacketReceivedEventHandler<PlayerOrientationPacket>() {
     override suspend fun handle(session: UranosSession, packet: PlayerOrientationPacket) {
-        session.earlyPlayer?.entity?.let { it.position = it.position.copy(yaw = packet.yaw, pitch = packet.pitch) }
+        session.earlyPlayer?.entity?.let { it.position = it.position.copy(yaw = packet.yaw, headPitch = packet.pitch) }
             ?: error("Player not yet initialized")
     }
 }

uranos-server/src/main/kotlin/space/uranos/net/packet/status/StatusProtocolHandler.kt

@@ -19,11 +19,11 @@ object StatusProtocolHandler : ProtocolPacketReceivedEventHandler(mapOf(
             response == null ->
                 session.disconnect(internalReason = "The response property of the ServerListInfoRequestEvent is null.")
 
-            else -> session.send(ResponsePacket(response))
+            else -> session.sendNow(ResponsePacket(response))
         }
     },
     PingPacket::class to PacketReceivedEventHandler.of<PingPacket> { session, packet ->
-        session.send(PongPacket(packet.payload))
+        session.sendNow(PongPacket(packet.payload))
         session.disconnect()
     }
 ))

uranos-server/src/main/kotlin/space/uranos/player/UranosPlayer.kt

@@ -44,12 +44,12 @@ class UranosPlayer(
     override var selectedHotbarSlot by container.ifChanged(
         selectedHotbarSlot,
         { clampArgument("selectedHotbarSlot", 0..8, it) }) {
-        session.send(SelectedHotbarSlotPacket(it))
+        session.sendNow(SelectedHotbarSlotPacket(it))
     }
 
     override var playerListName by container.ifChanged<TextComponent?>(TextComponent of name) { value ->
         session.server.players.forEach {
-            it.session.sendNextTick(PlayerInfoPacket(PlayerInfoPacket.Action.UpdateDisplayName(mapOf(uuid to value))))
+            it.session.send(PlayerInfoPacket(PlayerInfoPacket.Action.UpdateDisplayName(mapOf(uuid to value))))
         }
     }
 
@@ -90,7 +90,7 @@ class UranosPlayer(
 
     private suspend fun sendChunksAndLight() {
         val chunks = currentlyViewedChunks.sortedBy { abs(it.key.x) + abs(it.key.z) }
-        chunks.forEach { session.send(ChunkLightDataPacket(it.key, it.getLightData(this))) }
+        chunks.forEach { session.sendNow(ChunkLightDataPacket(it.key, it.getLightData(this))) }
-        chunks.forEach { session.send(ChunkDataPacket(it.key, it.getData(this))) }
+        chunks.forEach { session.sendNow(ChunkDataPacket(it.key, it.getData(this))) }
     }
 }