Paper/patches/server/0157-Expose-client-protocol-version-and-virtual-host.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Minecrell <minecrell@minecrell.net>
Date: Tue, 10 Oct 2017 18:45:20 +0200
Subject: [PATCH] Expose client protocol version and virtual host


diff --git a/src/main/java/com/destroystokyo/paper/network/PaperNetworkClient.java b/src/main/java/com/destroystokyo/paper/network/PaperNetworkClient.java
new file mode 100644
index 0000000000000000000000000000000000000000..a5a7624f1f372a26b982836cd31cff15e2589e9b
--- /dev/null
+++ b/src/main/java/com/destroystokyo/paper/network/PaperNetworkClient.java
@@ -0,0 +1,49 @@
+package com.destroystokyo.paper.network;
+
+import java.net.InetSocketAddress;
+
+import javax.annotation.Nullable;
+import net.minecraft.network.Connection;
+
+public class PaperNetworkClient implements NetworkClient {
+
+    private final Connection networkManager;
+
+    PaperNetworkClient(Connection networkManager) {
+        this.networkManager = networkManager;
+    }
+
+    @Override
+    public InetSocketAddress getAddress() {
+        return (InetSocketAddress) this.networkManager.getRemoteAddress();
+    }
+
+    @Override
+    public int getProtocolVersion() {
+        return this.networkManager.protocolVersion;
+    }
+
+    @Nullable
+    @Override
+    public InetSocketAddress getVirtualHost() {
+        return this.networkManager.virtualHost;
+    }
+
+    public static InetSocketAddress prepareVirtualHost(String host, int port) {
+        int len = host.length();
+
+        // FML appends a marker to the host to recognize FML clients (\0FML\0)
+        int pos = host.indexOf('\0');
+        if (pos >= 0) {
+            len = pos;
+        }
+
+        // When clients connect with a SRV record, their host contains a trailing '.'
+        if (len > 0 && host.charAt(len -  1) == '.') {
+            len--;
+        }
+
+        return InetSocketAddress.createUnresolved(host.substring(0, len), port);
+    }
+
+}
diff --git a/src/main/java/net/minecraft/network/Connection.java b/src/main/java/net/minecraft/network/Connection.java
index 0ccfdceea8e211c595be2dad2392876109b4eeef..1321b9adba4c9e45dce0f717d44a7cb4e64b9bf6 100644
--- a/src/main/java/net/minecraft/network/Connection.java
+++ b/src/main/java/net/minecraft/network/Connection.java
@@ -120,6 +120,10 @@ public class Connection extends SimpleChannelInboundHandler<Packet<?>> {
     @Nullable
     BandwidthDebugMonitor bandwidthDebugMonitor;
     public String hostname = ""; // CraftBukkit - add field
+    // Paper start - NetworkClient implementation
+    public int protocolVersion;
+    public java.net.InetSocketAddress virtualHost;
+    // Paper end
 
     // Paper start - add utility methods
     public final net.minecraft.server.level.ServerPlayer getPlayer() {
diff --git a/src/main/java/net/minecraft/server/network/ServerHandshakePacketListenerImpl.java b/src/main/java/net/minecraft/server/network/ServerHandshakePacketListenerImpl.java
index 9214fb6b8e21ff6aee8be0691f1fe6e41c901ba3..65333e0244d7c3c415266f1740929761ca890af7 100644
--- a/src/main/java/net/minecraft/server/network/ServerHandshakePacketListenerImpl.java
+++ b/src/main/java/net/minecraft/server/network/ServerHandshakePacketListenerImpl.java
@@ -69,6 +69,10 @@ public class ServerHandshakePacketListenerImpl implements ServerHandshakePacketL
                 throw new UnsupportedOperationException("Invalid intention " + String.valueOf(packet.intention()));
         }
 
+        // Paper start - NetworkClient implementation
+        this.connection.protocolVersion = packet.protocolVersion();
+        this.connection.virtualHost = com.destroystokyo.paper.network.PaperNetworkClient.prepareVirtualHost(packet.hostName(), packet.port());
+        // Paper end
     }
 
     private void beginLogin(ClientIntentionPacket packet, boolean transfer) {
diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
index a9922e5f5c19cd6455b6ca9a3db7aa0a42f99524..7e1f6e23980f12786abaa4218d8d77dd1a8feb3c 100644
--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
+++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
@@ -332,6 +332,20 @@ public class CraftPlayer extends CraftHumanEntity implements Player {
         this.getHandle().transferCookieConnection.sendPacket(new ClientboundTransferPacket(host, port));
     }
 
+    // Paper start - Implement NetworkClient
+    @Override
+    public int getProtocolVersion() {
+        if (getHandle().connection == null) return -1;
+        return getHandle().connection.connection.protocolVersion;
+    }
+
+    @Override
+    public InetSocketAddress getVirtualHost() {
+        if (getHandle().connection == null) return null;
+        return getHandle().connection.connection.virtualHost;
+    }
+    // Paper end
+
     @Override
     public double getEyeHeight(boolean ignorePose) {
         if (ignorePose) {