From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: kashike <kashike@vq.lc>
Date: Wed, 13 Apr 2016 20:21:38 -0700
Subject: [PATCH] Add handshake event to allow plugins to handle client
 handshaking logic themselves


diff --git a/src/main/java/net/minecraft/server/network/ServerHandshakePacketListenerImpl.java b/src/main/java/net/minecraft/server/network/ServerHandshakePacketListenerImpl.java
index 4a649a2006f907c9b7542843ec6938d9375ca645..0d9658b1c6b5912a34058c0ce53b8e7f8c28afac 100644
--- a/src/main/java/net/minecraft/server/network/ServerHandshakePacketListenerImpl.java
+++ b/src/main/java/net/minecraft/server/network/ServerHandshakePacketListenerImpl.java
@@ -89,9 +89,44 @@ public class ServerHandshakePacketListenerImpl implements ServerHandshakePacketL
                     this.connection.disconnect(ichatmutablecomponent);
                 } else {
                     this.connection.setListener(new ServerLoginPacketListenerImpl(this.server, this.connection));
+                // Paper start - handshake event
+                boolean proxyLogicEnabled = org.spigotmc.SpigotConfig.bungee;
+                boolean handledByEvent = false;
+                // Try and handle the handshake through the event
+                if (com.destroystokyo.paper.event.player.PlayerHandshakeEvent.getHandlerList().getRegisteredListeners().length != 0) { // Hello? Can you hear me?
+                    java.net.SocketAddress socketAddress = this.connection.address;
+                    String hostnameOfRemote = socketAddress instanceof java.net.InetSocketAddress ? ((java.net.InetSocketAddress) socketAddress).getHostString() : InetAddress.getLoopbackAddress().getHostAddress();
+                    com.destroystokyo.paper.event.player.PlayerHandshakeEvent event = new com.destroystokyo.paper.event.player.PlayerHandshakeEvent(packet.hostName(), hostnameOfRemote, !proxyLogicEnabled);
+                    if (event.callEvent()) {
+                        // If we've failed somehow, let the client know so and go no further.
+                        if (event.isFailed()) {
+                            Component component = io.papermc.paper.adventure.PaperAdventure.asVanilla(event.failMessage());
+                            this.connection.send(new ClientboundLoginDisconnectPacket(component));
+                            this.connection.disconnect(component);
+                            return;
+                        }
+
+                        if (event.getServerHostname() != null) {
+                            // change hostname
+                            packet = new ClientIntentionPacket(
+                                packet.protocolVersion(),
+                                event.getServerHostname(),
+                                packet.port(),
+                                packet.intention()
+                            );
+                        }
+                        if (event.getSocketAddressHostname() != null) this.connection.address = new java.net.InetSocketAddress(event.getSocketAddressHostname(), socketAddress instanceof java.net.InetSocketAddress ? ((java.net.InetSocketAddress) socketAddress).getPort() : 0);
+                        this.connection.spoofedUUID = event.getUniqueId();
+                        this.connection.spoofedProfile = gson.fromJson(event.getPropertiesJson(), com.mojang.authlib.properties.Property[].class);
+                        handledByEvent = true; // Hooray, we did it!
+                    }
+                }
                     // Spigot Start
                     String[] split = packet.hostName().split("\00");
-                    if (org.spigotmc.SpigotConfig.bungee) {
+                    // Don't try and handle default logic if it's been handled by the event.
+                    if (!handledByEvent && proxyLogicEnabled) {
+                        // Paper end
+                    // if (org.spigotmc.SpigotConfig.bungee) { // Paper - comment out, we check above!
                         if ( ( split.length == 3 || split.length == 4 ) && ( ServerHandshakePacketListenerImpl.HOST_PATTERN.matcher( split[1] ).matches() ) ) {
                             this.connection.hostname = split[0];
                             this.connection.address = new java.net.InetSocketAddress(split[1], ((java.net.InetSocketAddress) this.connection.getRemoteAddress()).getPort());