Leaf/patches/server/0022-Purpur-Alternative-Keepalive-Handling.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: William Blake Galbreath <blake.galbreath@gmail.com>
Date: Fri, 11 Oct 2019 00:17:39 -0500
Subject: [PATCH] Purpur: Alternative Keepalive Handling

Original license: MIT
Original project: https://github.com/PurpurMC/Purpur

diff --git a/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java b/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
index 86e5e0caf3b341d5556665e5f5fd7d158d639118..42de344dffd678158030c722c0cc0fef3f8c3fc6 100644
--- a/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
+++ b/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
@@ -260,6 +260,7 @@ public class ServerGamePacketListenerImpl implements ServerPlayerConnection, Tic
     private long keepAliveTime = Util.getMillis();
     private boolean keepAlivePending;
     private long keepAliveChallenge;
+    private it.unimi.dsi.fastutil.longs.LongList keepAlives = new it.unimi.dsi.fastutil.longs.LongArrayList(); // Purpur
     // CraftBukkit start - multithreaded fields
     private final AtomicInteger chatSpamTickCount = new AtomicInteger();
     private final java.util.concurrent.atomic.AtomicInteger tabSpamLimiter = new java.util.concurrent.atomic.AtomicInteger(); // Paper - configurable tab spam limits
@@ -397,6 +398,21 @@ public class ServerGamePacketListenerImpl implements ServerPlayerConnection, Tic
         long currentTime = Util.getMillis();
         long elapsedTime = currentTime - this.keepAliveTime;
 
+        // Purpur start
+        if (org.dreeam.leaf.LeafConfig.useAlternateKeepAlive) {
+            if (elapsedTime >= 1000L) { // 1 second
+                if (!processedDisconnect && keepAlives.size() * 1000L >= KEEPALIVE_LIMIT) {
+                    LOGGER.warn("{} was kicked due to keepalive timeout!", player.getName());
+                    disconnect(Component.translatable("disconnect.timeout"), org.bukkit.event.player.PlayerKickEvent.Cause.TIMEOUT);
+                } else {
+                    keepAliveTime = currentTime; // hijack this field for 1 second intervals
+                    keepAlives.add(currentTime); // currentTime is ID
+                    send(new ClientboundKeepAlivePacket(currentTime));
+                }
+            }
+        } else
+        // Purpur end
+
         if (this.keepAlivePending) {
             if (!this.processedDisconnect && elapsedTime >= KEEPALIVE_LIMIT) { // check keepalive limit, don't fire if already disconnected
                 ServerGamePacketListenerImpl.LOGGER.warn("{} was kicked due to keepalive timeout!", this.player.getScoreboardName()); // more info
@@ -3463,6 +3479,16 @@ public class ServerGamePacketListenerImpl implements ServerPlayerConnection, Tic
 
     @Override
     public void handleKeepAlive(ServerboundKeepAlivePacket packet) {
+        // Purpur start
+        if (org.dreeam.leaf.LeafConfig.useAlternateKeepAlive) {
+            long id = packet.getId();
+            if (keepAlives.size() > 0 && keepAlives.contains(id)) {
+                int ping = (int) (Util.getMillis() - id);
+                player.latency = (player.latency * 3 + ping) / 4;
+                keepAlives.clear(); // we got a valid response, lets roll with it and forget the rest
+            }
+        } else
+        // Purpur end
         //PacketUtils.ensureRunningOnSameThread(packet, this, this.player.getLevel()); // CraftBukkit // Paper - This shouldn't be on the main thread
         if (this.keepAlivePending && packet.getId() == this.keepAliveChallenge) {
             int i = (int) (Util.getMillis() - this.keepAliveTime);
diff --git a/src/main/java/org/dreeam/leaf/LeafConfig.java b/src/main/java/org/dreeam/leaf/LeafConfig.java
index f87f4f19738dfe8b58d3dbf0c27933fd3ec93883..9403774691cb83a3b916b4e0dc603385aceb4f4d 100644
--- a/src/main/java/org/dreeam/leaf/LeafConfig.java
+++ b/src/main/java/org/dreeam/leaf/LeafConfig.java
@@ -268,4 +268,9 @@ public class LeafConfig {
     private static void tileentitySetting() {
         persistentTileEntityDisplayNames = getBoolean("gameplay-mechanics.persistent-tileentity-display-names-and-lore", persistentTileEntityDisplayNames);
     }
+
+    public static boolean useAlternateKeepAlive = false;
+    private static void useAlternateKeepAlive() {
+        useAlternateKeepAlive = getBoolean("settings.use-alternate-keepalive", useAlternateKeepAlive);
+    }
 }