Expose client protocol version and virtual host

paper-server/patches/sources/net/minecraft/network/Connection.java.patch

@@ -29,11 +29,15 @@
      @Nullable
      private volatile PacketListener disconnectListener;
      @Nullable
-@@ -114,6 +119,19 @@
+@@ -114,6 +119,23 @@
      private volatile DisconnectionDetails delayedDisconnect;
      @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() {
@@ -49,7 +53,7 @@
  
      public Connection(PacketFlow side) {
          this.receiving = side;
-@@ -123,6 +141,9 @@
+@@ -123,6 +145,9 @@
          super.channelActive(channelhandlercontext);
          this.channel = channelhandlercontext.channel();
          this.address = this.channel.remoteAddress();
@@ -59,7 +63,7 @@
          if (this.delayedDisconnect != null) {
              this.disconnect(this.delayedDisconnect);
          }
-@@ -176,6 +197,7 @@
+@@ -176,6 +201,7 @@
  
              }
          }
@@ -67,7 +71,7 @@
      }
  
      protected void channelRead0(ChannelHandlerContext channelhandlercontext, Packet<?> packet) {
-@@ -205,7 +227,7 @@
+@@ -205,7 +231,7 @@
      }
  
      private static <T extends PacketListener> void genericsFtw(Packet<T> packet, PacketListener listener) {
@@ -76,7 +80,7 @@
      }
  
      private void validateListener(ProtocolInfo<?> state, PacketListener listener) {
-@@ -464,12 +486,15 @@
+@@ -464,12 +490,15 @@
      }
  
      public void disconnect(DisconnectionDetails disconnectionInfo) {
@@ -93,7 +97,7 @@
              this.disconnectionDetails = disconnectionInfo;
          }
  
-@@ -537,7 +562,7 @@
+@@ -537,7 +566,7 @@
      }
  
      public void configurePacketHandler(ChannelPipeline pipeline) {
@@ -102,7 +106,7 @@
              public void write(ChannelHandlerContext channelhandlercontext, Object object, ChannelPromise channelpromise) throws Exception {
                  super.write(channelhandlercontext, object, channelpromise);
              }
-@@ -661,6 +686,7 @@
+@@ -661,6 +690,7 @@
  
                      packetlistener1.onDisconnect(disconnectiondetails);
                  }

paper-server/patches/sources/net/minecraft/server/network/ServerHandshakePacketListenerImpl.java.patch

@@ -31,7 +31,15 @@
          switch (packet.intention()) {
              case LOGIN:
                  this.beginLogin(packet, false);
-@@ -59,19 +74,112 @@
+@@ -55,23 +70,120 @@
+                 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) {
          this.connection.setupOutboundProtocol(LoginProtocols.CLIENTBOUND);

paper-server/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);
+    }
+
+}

paper-server/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java

@@ -341,6 +341,20 @@ 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) {