Call PaperServerListPingEvent for legacy pings

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

@@ -25,22 +25,33 @@
          bytebuf.markReaderIndex();
          boolean flag = true;
  
-@@ -34,11 +45,12 @@
+@@ -34,11 +45,23 @@
  
                  SocketAddress socketaddress = channelhandlercontext.channel().remoteAddress();
                  int i = bytebuf.readableBytes();
 -                String s;
 +                String s = null; // Paper
-+                org.bukkit.event.server.ServerListPingEvent event = org.bukkit.craftbukkit.event.CraftEventFactory.callServerListPingEvent(socketaddress, this.server.getMotd(), this.server.getPlayerCount(), this.server.getMaxPlayers()); // CraftBukkit
++                // org.bukkit.event.server.ServerListPingEvent event = org.bukkit.craftbukkit.event.CraftEventFactory.callServerListPingEvent(socketaddress, this.server.getMotd(), this.server.getPlayerCount(), this.server.getMaxPlayers()); // CraftBukkit // Paper
++                com.destroystokyo.paper.event.server.PaperServerListPingEvent event; // Paper
  
                  if (i == 0) {
                      LegacyQueryHandler.LOGGER.debug("Ping: (<1.3.x) from {}", socketaddress);
 -                    s = LegacyQueryHandler.createVersion0Response(this.server);
-+                    s = LegacyQueryHandler.createVersion0Response(this.server, event); // CraftBukkit
++
++                    // Paper start - Call PaperServerListPingEvent and use results
++                    event = com.destroystokyo.paper.network.PaperLegacyStatusClient.processRequest(net.minecraft.server.MinecraftServer.getServer(), (java.net.InetSocketAddress) socketaddress, 39, null);
++                    if (event == null) {
++                        channelhandlercontext.close();
++                        bytebuf.release();
++                        flag = false;
++                        return;
++                    }
++                    s = String.format(Locale.ROOT, "%s\u00a7%d\u00a7%d", com.destroystokyo.paper.network.PaperLegacyStatusClient.getUnformattedMotd(event), event.getNumPlayers(), event.getMaxPlayers());
++                    // Paper end
                      LegacyQueryHandler.sendFlushAndClose(channelhandlercontext, LegacyQueryHandler.createLegacyDisconnectPacket(channelhandlercontext.alloc(), s));
                  } else {
                      if (bytebuf.readUnsignedByte() != 1) {
-@@ -46,16 +58,24 @@
+@@ -46,16 +69,35 @@
                      }
  
                      if (bytebuf.isReadable()) {
@@ -66,11 +77,22 @@
                      }
  
 -                    s = LegacyQueryHandler.createVersion1Response(this.server);
-+                    if (s == null) s = LegacyQueryHandler.createVersion1Response(this.server, event); // CraftBukkit // Paper
++                    if (s == null) {
++                        // Paper start - Call PaperServerListPingEvent and use results
++                        event = com.destroystokyo.paper.network.PaperLegacyStatusClient.processRequest(net.minecraft.server.MinecraftServer.getServer(), (java.net.InetSocketAddress) socketaddress, 127, null); // Paper
++                        if (event == null) {
++                            channelhandlercontext.close();
++                            bytebuf.release();
++                            flag = false;
++                            return;
++                        }
++                        s = String.format(Locale.ROOT, "\u00a71\u0000%d\u0000%s\u0000%s\u0000%d\u0000%d", new Object[] { event.getProtocolVersion(), this.server.getServerVersion(), event.getMotd(), event.getNumPlayers(), event.getMaxPlayers()}); // CraftBukkit
++                        // Paper end
++                    }
                      LegacyQueryHandler.sendFlushAndClose(channelhandlercontext, LegacyQueryHandler.createLegacyDisconnectPacket(channelhandlercontext.alloc(), s));
                  }
  
-@@ -106,14 +126,102 @@
+@@ -106,14 +148,110 @@
          }
      }
  
@@ -139,8 +161,16 @@
 +
 +        LOGGER.debug("Ping: (1.6) from {}", ctx.channel().remoteAddress());
 +
-+        String response = String.format("\u00a71\u0000%d\u0000%s\u0000%s\u0000%d\u0000%d",
-+            Byte.MAX_VALUE, server.getServerVersion(), server.getMotd(), server.getPlayerCount(), server.getMaxPlayers());
++        java.net.InetSocketAddress virtualHost = com.destroystokyo.paper.network.PaperNetworkClient.prepareVirtualHost(host, port);
++        com.destroystokyo.paper.event.server.PaperServerListPingEvent event = com.destroystokyo.paper.network.PaperLegacyStatusClient.processRequest(
++                server, (java.net.InetSocketAddress) ctx.channel().remoteAddress(), protocolVersion, virtualHost);
++        if (event == null) {
++            ctx.close();
++            return null;
++        }
++
++        String response = String.format("\u00a71\u0000%d\u0000%s\u0000%s\u0000%d\u0000%d", event.getProtocolVersion(), event.getVersion(),
++            com.destroystokyo.paper.network.PaperLegacyStatusClient.getMotd(event), event.getNumPlayers(), event.getMaxPlayers());
 +        return response;
      }
  

paper-server/src/main/java/com/destroystokyo/paper/network/PaperLegacyStatusClient.java

@@ -0,0 +1,75 @@
+package com.destroystokyo.paper.network;
+
+import com.destroystokyo.paper.event.server.PaperServerListPingEvent;
+import net.kyori.adventure.text.serializer.plain.PlainTextComponentSerializer;
+import net.minecraft.ChatFormatting;
+import net.minecraft.server.MinecraftServer;
+import org.apache.commons.lang3.StringUtils;
+
+import java.net.InetSocketAddress;
+
+import javax.annotation.Nullable;
+
+public final class PaperLegacyStatusClient implements StatusClient {
+
+    private final InetSocketAddress address;
+    private final int protocolVersion;
+    @Nullable private final InetSocketAddress virtualHost;
+
+    private PaperLegacyStatusClient(InetSocketAddress address, int protocolVersion, @Nullable InetSocketAddress virtualHost) {
+        this.address = address;
+        this.protocolVersion = protocolVersion;
+        this.virtualHost = virtualHost;
+    }
+
+    @Override
+    public InetSocketAddress getAddress() {
+        return this.address;
+    }
+
+    @Override
+    public int getProtocolVersion() {
+        return this.protocolVersion;
+    }
+
+    @Nullable
+    @Override
+    public InetSocketAddress getVirtualHost() {
+        return this.virtualHost;
+    }
+
+    @Override
+    public boolean isLegacy() {
+        return true;
+    }
+
+    public static PaperServerListPingEvent processRequest(MinecraftServer server,
+            InetSocketAddress address, int protocolVersion, @Nullable InetSocketAddress virtualHost) {
+
+        PaperServerListPingEvent event =  new PaperServerListPingEventImpl(server,
+                new PaperLegacyStatusClient(address, protocolVersion, virtualHost), Byte.MAX_VALUE, null);
+        server.server.getPluginManager().callEvent(event);
+
+        if (event.isCancelled()) {
+            return null;
+        }
+
+        return event;
+    }
+
+    @SuppressWarnings("deprecation") // Valid as this is the legacy status client
+    public static String getMotd(PaperServerListPingEvent event) {
+        return getFirstLine(event.getMotd());
+    }
+
+    public static String getUnformattedMotd(PaperServerListPingEvent event) {
+        // Strip color codes and all other occurrences of the color char (because it's used as delimiter)
+        return getFirstLine(StringUtils.remove(PlainTextComponentSerializer.plainText().serialize(event.motd()), ChatFormatting.PREFIX_CODE));
+    }
+
+    private static String getFirstLine(String s) {
+        int pos = s.indexOf('\n');
+        return pos >= 0 ? s.substring(0, pos) : s;
+    }
+
+}