Adding more options for configuring ping passthrough. (#1870)

* Added 'ALLBUTVERSION' option for ping passthrough.

* Added more configuration options for ping passthrough.

* Updated default velocity.toml

* Add support for the legacy ping passthrough.

* Removed legacy ping passthrough & added config migration

- Bumped config-version to 2.8
- Updated comments and grammar
- Removed legacy ping passthrough in the config

* Cleaned up code to match code style

* Update to latest

* Move ping passthrough into its own section

* Reorder migrations so they occur in the right order.

* Clean up ping passthrough related code.

* Update file dates and cleanup/consolidate ping-passthrough code.

* Update proxy/src/main/java/com/velocitypowered/proxy/config/PingPassthroughMode.java

* Update proxy/src/main/java/com/velocitypowered/proxy/config/PingPassthroughMode.java

* Remaining nits

- Read a string instead of LegacyPingPassthroughMode
- Update `announce-forge`'s comment in `PingPassthroughMigration`
- Consume `Config` instead of `CommentedConfig` in `PingPassthroughMode#fromConfig`

---------

Co-authored-by: TheMiningTeamYT <loanisamazing@outlook.com>
Co-authored-by: ButterDebugger <34288129+ButterDebugger@users.noreply.github.com>
Co-authored-by: Wouter Gritter <wouter@gritter.nl>

proxy/src/main/java/com/velocitypowered/proxy/config/PingPassthroughMode.java

@@ -16,13 +16,49 @@
  */
 
 package com.velocitypowered.proxy.config;
+import com.electronwill.nightconfig.core.Config;
 
 /**
- * Supported passthrough modes for ping passthrough.
+ * Object to contain all the things that can be toggled for ping passthrough.
+ *
+ * @param version     Whether the version should be passed through.
+ * @param players     Whether the player count should be passed through.
+ * @param description Whether the description should be passed through.
+ * @param favicon     Whether the favicon should be passed through.
+ * @param modinfo     Whether the modinfo should be passed through.
  */
-public enum PingPassthroughMode {
+public record PingPassthroughMode(boolean version, boolean players,
-  DISABLED,
+    boolean description, boolean favicon, boolean modinfo) {
-  MODS,
+  public static final PingPassthroughMode DEFAULT = new PingPassthroughMode();
-  DESCRIPTION,
+  
-  ALL
+  /**
+   * Creates a default PingPassthroughMode.
+   */
+  private PingPassthroughMode() {
+    this(false, false, false, false, false);
+  }
+
+  /**
+   * Returns a PingPassthroughMode from a config section, or the default if the section is null.
+   * Based on the code for PacketLimiterConfig.
+   *
+   * @param config The configuration object to parse.
+   * @return The PingPassthroughMode, or the default if {@code config} is null.
+   */
+  public static PingPassthroughMode fromConfig(Config config) {
+    if (config == null) {
+      return DEFAULT;
+    }
+    return new PingPassthroughMode(
+        config.getOrElse("version", DEFAULT.version()),
+        config.getOrElse("players", DEFAULT.players()),
+        config.getOrElse("description", DEFAULT.description()),
+        config.getOrElse("favicon", DEFAULT.favicon()),
+        config.getOrElse("modinfo", DEFAULT.modinfo()));
+  }
+
+  public boolean enabled() {
+    return this.version || this.players || this.description || this.favicon
+      || this.modinfo;
+  }
 }

proxy/src/main/java/com/velocitypowered/proxy/config/VelocityConfiguration.java

@@ -32,6 +32,7 @@ import com.velocitypowered.proxy.config.migration.KeyAuthenticationMigration;
 import com.velocitypowered.proxy.config.migration.MiniMessageTranslationsMigration;
 import com.velocitypowered.proxy.config.migration.MotdMigration;
 import com.velocitypowered.proxy.config.migration.PacketLimiterMigration;
+import com.velocitypowered.proxy.config.migration.PingPassthroughMigration;
 import com.velocitypowered.proxy.config.migration.TransferIntegrationMigration;
 import com.velocitypowered.proxy.util.AddressUtil;
 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
@@ -79,7 +80,7 @@ public class VelocityConfiguration implements ProxyConfig {
   @Expose
   private boolean onlineModeKickExistingPlayers = false;
   @Expose
-  private PingPassthroughMode pingPassthrough = PingPassthroughMode.DISABLED;
+  private PingPassthroughMode pingPassthrough = PingPassthroughMode.DEFAULT;
   @Expose
   private boolean samplePlayersInPing = false;
   private final Servers servers;
@@ -513,7 +514,8 @@ public class VelocityConfiguration implements ProxyConfig {
           new MotdMigration(),
           new MiniMessageTranslationsMigration(),
           new TransferIntegrationMigration(),
-          new PacketLimiterMigration()
+          new PacketLimiterMigration(),
+          new PingPassthroughMigration(),
       };
 
       for (final ConfigurationMigration migration : migrations) {
@@ -555,9 +557,7 @@ public class VelocityConfiguration implements ProxyConfig {
       final CommentedConfig metricsConfig = config.get("metrics");
       final PlayerInfoForwarding forwardingMode = config.getEnumOrElse(
               "player-info-forwarding-mode", PlayerInfoForwarding.NONE);
-      final PingPassthroughMode pingPassthroughMode = config.getEnumOrElse("ping-passthrough",
+      final PingPassthroughMode pingPassthrough = PingPassthroughMode.fromConfig(config.get("ping-passthrough"));
-              PingPassthroughMode.DISABLED);
-
       final boolean samplePlayersInPing = config.getOrElse("sample-players-in-ping", false);
 
       final String bind = config.getOrElse("bind", "0.0.0.0:25565");
@@ -590,7 +590,7 @@ public class VelocityConfiguration implements ProxyConfig {
               forwardingMode,
               forwardingSecret,
               kickExisting,
-              pingPassthroughMode,
+              pingPassthrough,
               samplePlayersInPing,
               enablePlayerAddressLogging,
               new Servers(serversConfig),

proxy/src/main/java/com/velocitypowered/proxy/config/migration/ConfigurationMigration.java

@@ -30,7 +30,8 @@ public sealed interface ConfigurationMigration
                 MotdMigration,
                 MiniMessageTranslationsMigration,
                 TransferIntegrationMigration,
-                PacketLimiterMigration {
+                PacketLimiterMigration,
+                PingPassthroughMigration {
   boolean shouldMigrate(CommentedFileConfig config);
 
   void migrate(CommentedFileConfig config, Logger logger) throws IOException;

proxy/src/main/java/com/velocitypowered/proxy/config/migration/PingPassthroughMigration.java

@@ -0,0 +1,105 @@
+/*
+ * Copyright (C) 2024-2026 Velocity Contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.velocitypowered.proxy.config.migration;
+
+import com.electronwill.nightconfig.core.file.CommentedFileConfig;
+import java.util.Locale;
+import org.apache.logging.log4j.Logger;
+
+/**
+ * Migrate the old ping passthrough entry to separate config entries.
+ */
+public final class PingPassthroughMigration implements ConfigurationMigration {
+  @Override
+  public boolean shouldMigrate(final CommentedFileConfig config) {
+    return configVersion(config) < 2.9;
+  }
+
+  @Override
+  public void migrate(final CommentedFileConfig config, final Logger logger) {
+    // Get legacy ping passthrough value
+    final String legacyMode = config.getOrElse("ping-passthrough", "DISABLED")
+        .toUpperCase(Locale.ROOT);
+    boolean version = false;
+    boolean players = false;
+    boolean description = false;
+    boolean favicon = false;
+    boolean modinfo = false;
+
+    switch (legacyMode) {
+      case "ALL":
+        version = true;
+        players = true;
+        description = true;
+        favicon = true;
+        modinfo = true;
+        break;
+      case "DESCRIPTION":
+        description = true;
+        modinfo = true;
+        break;
+      case "MODS":
+        modinfo = true;
+        break;
+      default: // DISABLED
+        break;
+    }
+
+    config.removeComment("ping-passthrough");
+    config.remove("ping-passthrough");
+
+    config.setComment("announce-forge",
+        " Announce whether or not your server supports Forge. If you run a modded server, we\n"
+            + " suggest turning this on.\n"
+            + "\n"
+            + " If your network runs one modpack consistently, consider using ping-passthrough.modinfo = true\n"
+            + " instead for a nicer display in the server list.");
+
+    config.set("ping-passthrough.version", version);
+    config.setComment(
+        "ping-passthrough.version",
+        " Should Velocity pass the version number from the backend server when responding to server list ping requests?"
+    );
+
+    config.set("ping-passthrough.players", players);
+    config.setComment(
+        "ping-passthrough.players",
+        " Should Velocity pass the player count from the backend server when responding to server list ping requests?"
+    );
+
+    config.set("ping-passthrough.description", description);
+    config.setComment(
+        "ping-passthrough.description",
+        " Should Velocity pass the description from the backend server when responding to server list ping requests?"
+    );
+
+    config.set("ping-passthrough.favicon", favicon);
+    config.setComment(
+        "ping-passthrough.favicon",
+        " Should Velocity pass the favicon (also known as the server icon) from the backend server when responding to server list ping requests?"
+    );
+
+    config.set("ping-passthrough.modinfo", modinfo);
+    config.setComment(
+        "ping-passthrough.modinfo",
+        " Should Velocity pass the mod list from the backend server when responding to server list ping requests?"
+    );
+
+    config.set("config-version", "2.9");
+  }
+}

proxy/src/main/java/com/velocitypowered/proxy/connection/util/ServerListPingHandler.java

@@ -23,6 +23,7 @@ import com.velocitypowered.api.network.ProtocolVersion;
 import com.velocitypowered.api.proxy.server.PingOptions;
 import com.velocitypowered.api.proxy.server.RegisteredServer;
 import com.velocitypowered.api.proxy.server.ServerPing;
+import com.velocitypowered.api.util.Favicon;
 import com.velocitypowered.api.util.ModInfo;
 import com.velocitypowered.proxy.VelocityServer;
 import com.velocitypowered.proxy.config.PingPassthroughMode;
@@ -100,60 +101,68 @@ public class ServerListPingHandler {
 
     CompletableFuture<List<ServerPing>> pingResponses = CompletableFutures.successfulAsList(pings,
         (ex) -> fallback);
-    return switch (mode) {
-      case ALL -> pingResponses.thenApply(responses -> {
-        // Find the first non-fallback
-        for (ServerPing response : responses) {
-          if (response == fallback) {
-            continue;
-          }
 
-          if (response.getDescriptionComponent() == null) {
+    // Return early if ping passthrough is not enabled
-            return response.asBuilder()
+    if (!mode.enabled()) {
-                .description(Component.empty())
+      return CompletableFuture.completedFuture(fallback);
-                .build();
+    }
-          }
 
-          return response;
+    return pingResponses.thenApply(responses -> {
+      // Find the first non-fallback
+      for (ServerPing response : responses) {
+        if (response == fallback) {
+          continue;
         }
-        return fallback;
-      });
-      case MODS -> pingResponses.thenApply(responses -> {
-        // Find the first non-fallback that contains a mod list
-        for (ServerPing response : responses) {
-          if (response == fallback) {
-            continue;
-          }
-          Optional<ModInfo> modInfo = response.getModinfo();
-          if (modInfo.isPresent()) {
-            return fallback.asBuilder().mods(modInfo.get()).build();
-          }
-        }
-        return fallback;
-      });
-      case DESCRIPTION -> pingResponses.thenApply(responses -> {
-        // Find the first non-fallback. If it includes a modlist, add it too.
-        for (ServerPing response : responses) {
-          if (response == fallback) {
-            continue;
-          }
-          if (response.getDescriptionComponent() == null) {
-            continue;
-          }
 
-          return new ServerPing(
+        ServerPing.Version version;
-              fallback.getVersion(),
+        if (mode.version()) {
-              fallback.getPlayers().orElse(null),
+          version = response.getVersion();
-              response.getDescriptionComponent(),
+        } else {
-              fallback.getFavicon().orElse(null),
+          version = fallback.getVersion();
-              response.getModinfo().orElse(null)
-          );
         }
-        return fallback;
+
-      });
+        ServerPing.Players players;
-      // Not possible, but covered for completeness.
+        if (mode.players()) {
-      default -> CompletableFuture.completedFuture(fallback);
+          players = response.getPlayers().orElse(null);
-    };
+        } else {
+          players = fallback.getPlayers().orElse(null);
+        }
+
+        Component description;
+        if (mode.description()) {
+          if (response.getDescriptionComponent() != null) {
+            description = response.getDescriptionComponent();
+          } else {
+            description = Component.empty();
+          }
+        } else {
+          description = fallback.getDescriptionComponent();
+        }
+
+        Favicon favicon;
+        if (mode.favicon()) {
+          favicon = response.getFavicon().orElse(null);
+        } else {
+          favicon = fallback.getFavicon().orElse(null);
+        }
+
+        ModInfo modinfo;
+        if (mode.modinfo()) {
+          modinfo = response.getModinfo().orElse(null);
+        } else {
+          modinfo = fallback.getModinfo().orElse(null);
+        }
+
+        return new ServerPing(
+            version,
+            players,
+            description,
+            favicon,
+            modinfo
+        );
+      }
+      return fallback;
+    });
   }
 
   /**
@@ -168,7 +177,7 @@ public class ServerListPingHandler {
         ? connection.getProtocolVersion() : ProtocolVersion.MAXIMUM_VERSION;
     PingPassthroughMode passthroughMode = configuration.getPingPassthrough();
 
-    if (passthroughMode == PingPassthroughMode.DISABLED) {
+    if (!passthroughMode.enabled()) {
       return CompletableFuture.completedFuture(constructLocalPing(shownVersion));
     } else {
       String virtualHostStr = connection.getVirtualHost().map(InetSocketAddress::getHostString)

proxy/src/main/resources/default-velocity.toml

@@ -1,5 +1,5 @@
 # Config version. Do not change this
-config-version = "2.8"
+config-version = "2.9"
 
 # What port should the proxy be bound to? By default, we'll bind to all addresses on port 25565.
 bind = "0.0.0.0:25565"
@@ -43,7 +43,7 @@ forwarding-secret-file = "forwarding.secret"
 # Announce whether or not your server supports Forge. If you run a modded server, we
 # suggest turning this on.
 # 
-# If your network runs one modpack consistently, consider using ping-passthrough = "mods"
+# If your network runs one modpack consistently, consider using ping-passthrough.modinfo = true
 # instead for a nicer display in the server list.
 announce-forge = false
 
@@ -51,21 +51,6 @@ announce-forge = false
 # any existing player who is online if a duplicate connection attempt is made.
 kick-existing-players = false
 
-# Should Velocity pass server list ping requests to a backend server?
-# Available options:
-# - "disabled":    No pass-through will be done. The velocity.toml and server-icon.png
-#                  will determine the initial server list ping response.
-# - "mods":        Passes only the mod list from your backend server into the response.
-#                  The first server in your try list (or forced host) with a mod list will be
-#                  used. If no backend servers can be contacted, Velocity won't display any
-#                  mod information.
-# - "description": Uses the description and mod list from the backend server. The first
-#                  server in the try (or forced host) list that responds is used for the
-#                  description and mod list.
-# - "all":         Uses the backend server's response as the proxy response. The Velocity
-#                  configuration is used if no servers could be contacted.
-ping-passthrough = "DISABLED"
-
 # If enabled (default is false), then a sample of the online players on the proxy will be visible
 # when hovering over the player count in the server list.
 # This doesn't have any effect when ping passthrough is set to either "description" or "all".
@@ -74,6 +59,18 @@ sample-players-in-ping = false
 # If not enabled (default is true) player IP addresses will be replaced by <ip address withheld> in logs
 enable-player-address-logging = true
 
+[ping-passthrough]
+# Should Velocity pass the version number from the backend server when responding to server list ping requests?
+version = false
+# Should Velocity pass the player count from the backend server when responding to server list ping requests?
+players = false
+# Should Velocity pass the description from the backend server when responding to server list ping requests?
+description = false
+# Should Velocity pass the favicon (also known as the server icon) from the backend server when responding to server list ping requests?
+favicon = false
+# Should Velocity pass the mod list from the backend server when responding to server list ping requests?
+modinfo = false
+
 [packet-limiter]
 # Size of the moving time window in seconds used to calculate average rates.
 # A larger window tolerates short bursts while still enforcing the configured limits over time.