Paper/patches/server/0896-Add-support-for-Proxy-Protocol.patch

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 3ff7814add16834c70494afb76d8a7788545d009..50d35d6e60f398501af447319de9d6ccd4db8b00 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -22,6 +22,7 @@ dependencies {
      */
     implementation("org.apache.logging.log4j:log4j-core:2.17.1") // Paper - implementation
     annotationProcessor("org.apache.logging.log4j:log4j-core:2.17.1") // Paper - Needed to generate meta for our Log4j plugins
+    implementation("io.netty:netty-codec-haproxy:4.1.76.Final")
     // Paper end
     implementation("org.apache.logging.log4j:log4j-iostreams:2.17.1") // Paper
     implementation("org.apache.logging.log4j:log4j-slf4j18-impl:2.17.1") // Paper
diff --git a/src/main/java/com/destroystokyo/paper/PaperConfig.java b/src/main/java/com/destroystokyo/paper/PaperConfig.java
index 72e17ac76e5f3ac1283bec2133f76bc197353dd6..d4ff14b9e6028259c27ea9cb2b4be587ebabfb41 100644
--- a/src/main/java/com/destroystokyo/paper/PaperConfig.java
+++ b/src/main/java/com/destroystokyo/paper/PaperConfig.java
@@ -647,4 +647,9 @@ public class PaperConfig {
     private static void useDimensionTypeForCustomSpawners() {
         useDimensionTypeForCustomSpawners = getBoolean("settings.use-dimension-type-for-custom-spawners", false);
     }
+
+    public static boolean useProxyProtocol;
+    private static void useProxyProtocol() {
+        useProxyProtocol = getBoolean("settings.proxy-protocol", false);
+    }
 }
diff --git a/src/main/java/net/minecraft/server/network/ServerConnectionListener.java b/src/main/java/net/minecraft/server/network/ServerConnectionListener.java
index 510a1fc4e315483809035b1e5c28b441f18a7c14..947f7afb1d61ece0b1a51b275b22f21ec2216dde 100644
--- a/src/main/java/net/minecraft/server/network/ServerConnectionListener.java
+++ b/src/main/java/net/minecraft/server/network/ServerConnectionListener.java
@@ -110,6 +110,12 @@ 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 (com.destroystokyo.paper.PaperConfig.useProxyProtocol) {
+                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 {
@@ -123,6 +129,30 @@ public class ServerConnectionListener {
                     int j = ServerConnectionListener.this.server.getRateLimitPacketsPerSecond();
                     Object object = j > 0 ? new RateKickingConnection(j) : new Connection(PacketFlow.SERVERBOUND);
 
+                    // Paper start - Add support for Proxy Protocol
+                    if (com.destroystokyo.paper.PaperConfig.useProxyProtocol) {
+                        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((Connection) object); // CraftBukkit - decompile error
                     pending.add((Connection) object); // Paper
                     channel.pipeline().addLast("packet_handler", (ChannelHandler) object);