From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: PanSzelescik <panszelescik@gmail.com>
Date: Thu, 7 Apr 2022 16:13:39 +0200
Subject: [PATCH] Add support for Proxy Protocol


diff --git a/build.gradle.kts b/build.gradle.kts
index e1e8f7c42f5e68da25b11c4cfadd67425395e558..7a17e05b630517a6861c34a4561198db62acf82a 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -20,6 +20,7 @@ dependencies {
      */
     implementation("org.apache.logging.log4j:log4j-core:2.14.1") // Paper - implementation
     annotationProcessor("org.apache.logging.log4j:log4j-core:2.14.1") // Paper - Needed to generate meta for our Log4j plugins
+    implementation("io.netty:netty-codec-haproxy:4.1.87.Final") // Paper - Add support for proxy protocol
     // Paper end
     implementation("org.apache.logging.log4j:log4j-iostreams:2.19.0") // Paper - remove exclusion
     implementation("org.ow2.asm:asm:9.4")
diff --git a/src/main/java/net/minecraft/server/network/ServerConnectionListener.java b/src/main/java/net/minecraft/server/network/ServerConnectionListener.java
index 17f42a4097d9c91bae2ccb02365498a0f7c7f8f8..0f578e870f2bed207a8650a31e89b3672ae8a57b 100644
--- a/src/main/java/net/minecraft/server/network/ServerConnectionListener.java
+++ b/src/main/java/net/minecraft/server/network/ServerConnectionListener.java
@@ -106,6 +106,12 @@ public class ServerConnectionListener {
             ServerConnectionListener.LOGGER.info("Paper: Using " + com.velocitypowered.natives.util.Natives.cipher.getLoadedVariant() + " cipher from Velocity.");
             // Paper end
 
+            // Paper start - indicate Proxy Protocol usage
+            if (io.papermc.paper.configuration.GlobalConfiguration.get().proxies.proxyProtocol) {
+                ServerConnectionListener.LOGGER.info("Paper: Using Proxy Protocol");
+            }
+            // Paper end
+
             this.channels.add(((ServerBootstrap) ((ServerBootstrap) (new ServerBootstrap()).channel(oclass)).childHandler(new ChannelInitializer<Channel>() {
                 protected void initChannel(Channel channel) {
                     try {
@@ -120,6 +126,30 @@ public class ServerConnectionListener {
                     int j = ServerConnectionListener.this.server.getRateLimitPacketsPerSecond();
                     Connection object = j > 0 ? new RateKickingConnection(j) : new Connection(PacketFlow.SERVERBOUND); // CraftBukkit - decompile error
 
+                    // Paper start - Add support for Proxy Protocol
+                    if (io.papermc.paper.configuration.GlobalConfiguration.get().proxies.proxyProtocol) {
+                        channel.pipeline().addAfter("timeout", "haproxy-decoder", new io.netty.handler.codec.haproxy.HAProxyMessageDecoder());
+                        channel.pipeline().addAfter("haproxy-decoder", "haproxy-handler", new ChannelInboundHandlerAdapter() {
+                            @Override
+                            public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
+                                if (msg instanceof io.netty.handler.codec.haproxy.HAProxyMessage message) {
+                                    if (message.command() == io.netty.handler.codec.haproxy.HAProxyCommand.PROXY) {
+                                        String realaddress = message.sourceAddress();
+                                        int realport = message.sourcePort();
+
+                                        SocketAddress socketaddr = new java.net.InetSocketAddress(realaddress, realport);
+
+                                        Connection connection = (Connection) channel.pipeline().get("packet_handler");
+                                        connection.address = socketaddr;
+                                    }
+                                } else {
+                                    super.channelRead(ctx, msg);
+                                }
+                            }
+                        });
+                    }
+                    // Paper end
+
                     //ServerConnectionListener.this.connections.add(object);
                     pending.add(object); // Paper
                     channelpipeline.addLast("packet_handler", (ChannelHandler) object);