From 1d4da8c32df5b22221639e245000a188dfdcaec7 Mon Sep 17 00:00:00 2001
From: Andrew Steinborn <git@steinborn.me>
Date: Thu, 20 Aug 2020 15:03:33 -0400
Subject: [PATCH] Correctly implement status protocol specification according
 to vanilla.

---
 .../proxy/connection/MinecraftConnection.java   | 10 ++++++----
 .../connection/client/StatusSessionHandler.java | 17 ++++++-----------
 2 files changed, 12 insertions(+), 15 deletions(-)

diff --git a/proxy/src/main/java/com/velocitypowered/proxy/connection/MinecraftConnection.java b/proxy/src/main/java/com/velocitypowered/proxy/connection/MinecraftConnection.java
index 70de89673..d9210e636 100644
--- a/proxy/src/main/java/com/velocitypowered/proxy/connection/MinecraftConnection.java
+++ b/proxy/src/main/java/com/velocitypowered/proxy/connection/MinecraftConnection.java
@@ -27,6 +27,7 @@ import com.velocitypowered.proxy.protocol.netty.MinecraftCompressDecoder;
 import com.velocitypowered.proxy.protocol.netty.MinecraftCompressEncoder;
 import com.velocitypowered.proxy.protocol.netty.MinecraftDecoder;
 import com.velocitypowered.proxy.protocol.netty.MinecraftEncoder;
+import com.velocitypowered.proxy.protocol.packet.Handshake;
 import com.velocitypowered.proxy.util.except.QuietDecoderException;
 import io.netty.buffer.ByteBuf;
 import io.netty.channel.Channel;
@@ -156,11 +157,12 @@ public class MinecraftConnection extends ChannelInboundHandlerAdapter {
         if (cause instanceof ReadTimeoutException) {
           logger.error("{}: read timed out", association);
         } else {
+          boolean frontlineHandler = sessionHandler instanceof LoginSessionHandler
+              || sessionHandler instanceof HandshakeSessionHandler
+              || sessionHandler instanceof StatusSessionHandler;
           boolean isQuietDecoderException = cause instanceof QuietDecoderException;
-          boolean willLogQuietDecoderException = !isQuietDecoderException
-              || (!(sessionHandler instanceof LoginSessionHandler)
-              && !(sessionHandler instanceof HandshakeSessionHandler));
-          if (willLogQuietDecoderException) {
+          boolean willLog = !isQuietDecoderException && !frontlineHandler;
+          if (willLog) {
             logger.error("{}: exception encountered in {}", association, sessionHandler, cause);
           } else {
             knownDisconnect = true;
diff --git a/proxy/src/main/java/com/velocitypowered/proxy/connection/client/StatusSessionHandler.java b/proxy/src/main/java/com/velocitypowered/proxy/connection/client/StatusSessionHandler.java
index a1d14ad28..ba9baaa2b 100644
--- a/proxy/src/main/java/com/velocitypowered/proxy/connection/client/StatusSessionHandler.java
+++ b/proxy/src/main/java/com/velocitypowered/proxy/connection/client/StatusSessionHandler.java
@@ -34,20 +34,17 @@ public class StatusSessionHandler implements MinecraftSessionHandler {
   private static final Logger logger = LogManager.getLogger(StatusSessionHandler.class);
   private static final QuietRuntimeException EXPECTED_AWAITING_REQUEST = new QuietRuntimeException(
       "Expected connection to be awaiting status request");
-  private static final QuietRuntimeException EXPECTED_RECEIVED_REQUEST = new QuietRuntimeException(
-      "Expected connection to be awaiting ping");
 
   private final VelocityServer server;
   private final MinecraftConnection connection;
   private final InboundConnection inbound;
-  private State state;
+  private boolean pingReceived = false;
 
   StatusSessionHandler(VelocityServer server, MinecraftConnection connection,
       InboundConnection inbound) {
     this.server = server;
     this.connection = connection;
     this.inbound = inbound;
-    this.state = State.AWAITING_REQUEST;
   }
 
   @Override
@@ -158,10 +155,10 @@ public class StatusSessionHandler implements MinecraftSessionHandler {
 
   @Override
   public boolean handle(LegacyPing packet) {
-    if (this.state != State.AWAITING_REQUEST) {
+    if (this.pingReceived) {
       throw EXPECTED_AWAITING_REQUEST;
     }
-    this.state = State.RECEIVED_REQUEST;
+    this.pingReceived = true;
     getInitialPing()
         .thenCompose(ping -> server.getEventManager().fire(new ProxyPingEvent(inbound, ping)))
         .thenAcceptAsync(event -> {
@@ -173,19 +170,17 @@ public class StatusSessionHandler implements MinecraftSessionHandler {
 
   @Override
   public boolean handle(StatusPing packet) {
-    if (this.state != State.RECEIVED_REQUEST) {
-      throw EXPECTED_RECEIVED_REQUEST;
-    }
     connection.closeWith(packet);
     return true;
   }
 
   @Override
   public boolean handle(StatusRequest packet) {
-    if (this.state != State.AWAITING_REQUEST) {
+    if (this.pingReceived) {
       throw EXPECTED_AWAITING_REQUEST;
     }
-    this.state = State.RECEIVED_REQUEST;
+    this.pingReceived = true;
+
     getInitialPing()
         .thenCompose(ping -> server.getEventManager().fire(new ProxyPingEvent(inbound, ping)))
         .thenAcceptAsync(