Allow NMS packet receiving

src/main/java/us/myles/ViaVersion/protocols/protocol1_9to1_8/Protocol1_9TO1_8.java

@@ -106,7 +106,7 @@ public class Protocol1_9TO1_8 extends Protocol {
             Bukkit.getPluginManager().registerEvents(new PaperPatch(), plugin);
         }
         if (plugin.getConfig().getBoolean("simulate-pt", true))
-            new ViaIdleThread(plugin.getPortedPlayers()).runTaskTimerAsynchronously(plugin, 1L, 1L); // Updates player's idle status
+            new ViaIdleThread(plugin.getPortedPlayers()).runTaskTimer(plugin, 1L, 1L); // Updates player's idle status
         if (plugin.getConfig().getBoolean("item-cache", true)) {
             new HandItemCache().runTaskTimerAsynchronously(plugin, 2L, 2L); // Updates player's items :)
             HandItemCache.CACHE = true;

src/main/java/us/myles/ViaVersion/protocols/protocol1_9to1_8/ViaIdleThread.java

@@ -1,7 +1,11 @@
 package us.myles.ViaVersion.protocols.protocol1_9to1_8;
 
 import io.netty.channel.ChannelHandlerContext;
+import org.bukkit.Bukkit;
+import org.bukkit.entity.Player;
 import org.bukkit.scheduler.BukkitRunnable;
+import us.myles.ViaVersion.ViaVersionPlugin;
+import us.myles.ViaVersion.api.ViaVersion;
 import us.myles.ViaVersion.api.data.UserConnection;
 import us.myles.ViaVersion.protocols.base.ProtocolInfo;
 import us.myles.ViaVersion.protocols.protocol1_9to1_8.storage.MovementTracker;
@@ -9,18 +13,33 @@ import us.myles.ViaVersion.util.PipelineUtil;
 import us.myles.ViaVersion.util.ReflectionUtil;
 
 import java.lang.reflect.Field;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
 import java.util.Map;
 import java.util.UUID;
 
 public class ViaIdleThread extends BukkitRunnable {
+    private static boolean USE_NMS = true;
     private final Map<UUID, UserConnection> portedPlayers;
-    private final Object idlePacket;
+    // Used for packet mode
-    private final Object idlePacket2;
+    private Object idlePacket;
+    private Object idlePacket2;
+    // Use for nms
+    private Method getHandle;
+    private Field connection;
+    private Method handleFlying;
 
     public ViaIdleThread(Map<UUID, UserConnection> portedPlayers) {
+        USE_NMS = ((ViaVersionPlugin) ViaVersion.getInstance()).getConfig().getBoolean("nms-player-ticking", true);
+
         this.portedPlayers = portedPlayers;
+        Class<?> idlePacketClass;
+        try {
+            idlePacketClass = ReflectionUtil.nms("PacketPlayInFlying");
+        } catch (ClassNotFoundException e) {
+            throw new RuntimeException("Couldn't find idle packet, help!", e);
+        }
         try {
-            Class<?> idlePacketClass = ReflectionUtil.nms("PacketPlayInFlying");
             idlePacket = idlePacketClass.newInstance();
             idlePacket2 = idlePacketClass.newInstance();
 
@@ -28,19 +47,51 @@ public class ViaIdleThread extends BukkitRunnable {
             flying.setAccessible(true);
 
             flying.set(idlePacket2, true);
-        } catch (NoSuchFieldException | InstantiationException | IllegalArgumentException | IllegalAccessException | ClassNotFoundException e) {
+        } catch (NoSuchFieldException | InstantiationException | IllegalArgumentException | IllegalAccessException e) {
-            throw new RuntimeException("Couldn't find/make player idle packet, help!", e);
+            throw new RuntimeException("Couldn't make player idle packet, help!", e);
         }
+        if(USE_NMS) {
+            try {
+                getHandle = ReflectionUtil.obc("entity.CraftPlayer").getDeclaredMethod("getHandle");
+            } catch (NoSuchMethodException | ClassNotFoundException e) {
+                throw new RuntimeException("Couldn't find CraftPlayer", e);
             }
 
+            try {
+                connection = ReflectionUtil.nms("EntityPlayer").getDeclaredField("playerConnection");
+            } catch (NoSuchFieldException | ClassNotFoundException e) {
+                throw new RuntimeException("Couldn't find Player Connection", e);
+            }
+
+            try {
+                handleFlying = ReflectionUtil.nms("PlayerConnection").getDeclaredMethod("a", idlePacketClass);
+            } catch (NoSuchMethodException | ClassNotFoundException e) {
+                throw new RuntimeException("Couldn't find CraftPlayer", e);
+            }
+        }
+    }
     @Override
     public void run() {
         for (UserConnection info : portedPlayers.values()) {
             if (info.get(ProtocolInfo.class).getPipeline().contains(Protocol1_9TO1_8.class)) {
                 long nextIdleUpdate = info.get(MovementTracker.class).getNextIdlePacket();
                 if (nextIdleUpdate <= System.currentTimeMillis()) {
-                    ChannelHandlerContext context = PipelineUtil.getContextBefore("decoder", info.getChannel().pipeline());
                     if (info.getChannel().isOpen()) {
+                        if (USE_NMS) {
+                            Player player = Bukkit.getPlayer(info.get(ProtocolInfo.class).getUuid());
+                            try {
+                                // Tick player
+                                Object entityPlayer = getHandle.invoke(player);
+                                Object pc = connection.get(entityPlayer);
+                                handleFlying.invoke(pc, (info.get(MovementTracker.class).isGround() ? idlePacket2 : idlePacket));
+                                // Tick world
+                                info.get(MovementTracker.class).incrementIdlePacket();
+                            } catch (IllegalAccessException | InvocationTargetException e) {
+                                e.printStackTrace();
+                            }
+                        } else {
+                            // Old method using packets.
+                            ChannelHandlerContext context = PipelineUtil.getContextBefore("decoder", info.getChannel().pipeline());
                             if (context != null) {
                                 if (info.get(MovementTracker.class).isGround()) {
                                     context.fireChannelRead(idlePacket2);
@@ -54,4 +105,5 @@ public class ViaIdleThread extends BukkitRunnable {
                 }
             }
         }
+    }
 }

src/main/resources/config.yml

@@ -16,6 +16,8 @@ hologram-patch: false
 hologram-y: -1
 # Enable player tick simulation, this fixes eating, drinking, nether portals.
 simulate-pt: true
+# Should we use nms player to simulate packets, (may fix anti-cheat issues)
+nms-player-ticking: true
 # Should we patch boss bars so they work? (Default: true, disable if you're having issues)
 bossbar-patch: true
 # If your boss bar flickers on 1.9, set this to 'true'. It will keep all boss bars on 100% (not recommended)