Adding more options for configuring ping passthrough.

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

@@ -0,0 +1,28 @@
+/*
+ * Copyright (C) 2018-2023 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;
+
+/**
+ * Legacy modes for ping passthrough.
+ */
+public enum LegacyPingPassthroughMode {
+  DISABLED,
+  MODS,
+  DESCRIPTION,
+  ALL
+}

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

@@ -18,11 +18,36 @@
 package com.velocitypowered.proxy.config;
 
 /**
- * Supported passthrough modes for ping passthrough.
+ * Object to contain all of the things that can be toggled for ping passthrough.
  */
-public enum PingPassthroughMode {
-  DISABLED,
-  MODS,
-  DESCRIPTION,
-  ALL
+public class PingPassthroughMode {
+  public boolean version;
+  public boolean players;
+  public boolean description;
+  public boolean favicon;
+  public boolean modinfo;
+
+  /**
+   * Passthrough mode constructor.
+   * Looking at other code, I'm not sure the constructor is supposed to need a javadoc style comment,
+   * but checkstyle was yelling at me because I didn't include one.
+   * Probably for the best.
+   *
+   * @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 PingPassthroughMode(boolean version, boolean players, boolean description, boolean favicon, boolean modinfo) {
+    this.version = version;
+    this.players = players;
+    this.description = description;
+    this.favicon = favicon;
+    this.modinfo = 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

@@ -77,7 +77,9 @@ public class VelocityConfiguration implements ProxyConfig {
   @Expose
   private boolean onlineModeKickExistingPlayers = false;
   @Expose
-  private PingPassthroughMode pingPassthrough = PingPassthroughMode.DISABLED;
+  private PingPassthroughMode pingPassthrough = new PingPassthroughMode(false, false, false, false, false);
+  @Expose
+  private LegacyPingPassthroughMode legacyPingPassthrough = LegacyPingPassthroughMode.DISABLED;
   private final Servers servers;
   private final ForcedHosts forcedHosts;
   @Expose
@@ -105,8 +107,9 @@ private VelocityConfiguration(String bind, String motd, int showMaxPlayers, bool
       boolean preventClientProxyConnections, boolean announceForge,
       PlayerInfoForwarding playerInfoForwardingMode, byte[] forwardingSecret,
       boolean onlineModeKickExistingPlayers, PingPassthroughMode pingPassthrough,
-      boolean enablePlayerAddressLogging, Servers servers, ForcedHosts forcedHosts,
-      Advanced advanced, Query query, Metrics metrics, boolean forceKeyAuthentication) {
+      LegacyPingPassthroughMode legacyPingPassthrough, boolean enablePlayerAddressLogging, 
+      Servers servers, ForcedHosts forcedHosts, Advanced advanced, Query query, 
+      Metrics metrics, boolean forceKeyAuthentication) {
     this.bind = bind;
     this.motd = motd;
     this.showMaxPlayers = showMaxPlayers;
@@ -117,6 +120,7 @@ private VelocityConfiguration(String bind, String motd, int showMaxPlayers, bool
     this.forwardingSecret = forwardingSecret;
     this.onlineModeKickExistingPlayers = onlineModeKickExistingPlayers;
     this.pingPassthrough = pingPassthrough;
+    this.legacyPingPassthrough = legacyPingPassthrough;
     this.enablePlayerAddressLogging = enablePlayerAddressLogging;
     this.servers = servers;
     this.forcedHosts = forcedHosts;
@@ -371,6 +375,10 @@ public PingPassthroughMode getPingPassthrough() {
     return pingPassthrough;
   }
 
+  public LegacyPingPassthroughMode getLegacyPingPassthrough() {
+    return legacyPingPassthrough;
+  }
+
   public boolean isPlayerAddressLoggingEnabled() {
     return enablePlayerAddressLogging;
   }
@@ -500,9 +508,14 @@ public static VelocityConfiguration read(Path path) throws IOException {
       final CommentedConfig metricsConfig = config.get("metrics");
       final PlayerInfoForwarding forwardingMode = config.getEnumOrElse(
               "player-info-forwarding-mode", PlayerInfoForwarding.NONE);
-      final PingPassthroughMode pingPassthroughMode = config.getEnumOrElse("ping-passthrough",
-              PingPassthroughMode.DISABLED);
-
+      final LegacyPingPassthroughMode legacyPingPassthrough = config.getEnumOrElse("ping-passthrough",
+              LegacyPingPassthroughMode.DISABLED);
+      final PingPassthroughMode pingPassthrough = new PingPassthroughMode(
+              config.getOrElse("ping-passthrough-version", false),
+              config.getOrElse("ping-passthrough-players", false),
+              config.getOrElse("ping-passthrough-description", false),
+              config.getOrElse("ping-passthrough-favicon", false),
+              config.getOrElse("ping-passthrough-modinfo", false));
       final String bind = config.getOrElse("bind", "0.0.0.0:25577");
       final int maxPlayers = config.getIntOrElse("show-max-players", 500);
       final boolean onlineMode = config.getOrElse("online-mode", true);
@@ -532,7 +545,8 @@ public static VelocityConfiguration read(Path path) throws IOException {
               forwardingMode,
               forwardingSecret,
               kickExisting,
-              pingPassthroughMode,
+              pingPassthrough,
+              legacyPingPassthrough,
               enablePlayerAddressLogging,
               new Servers(serversConfig),
               new ForcedHosts(forcedHostsConfig),

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

@@ -23,8 +23,10 @@
 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.LegacyPingPassthroughMode;
 import com.velocitypowered.proxy.config.PingPassthroughMode;
 import com.velocitypowered.proxy.config.VelocityConfiguration;
 import com.velocitypowered.proxy.server.VelocityRegisteredServer;
@@ -63,7 +65,8 @@ private ServerPing constructLocalPing(ProtocolVersion version) {
   }
 
   private CompletableFuture<ServerPing> attemptPingPassthrough(VelocityInboundConnection connection,
-      PingPassthroughMode mode, List<String> servers, ProtocolVersion responseProtocolVersion) {
+      PingPassthroughMode mode, LegacyPingPassthroughMode legacyMode, 
+      List<String> servers, ProtocolVersion responseProtocolVersion) {
     ServerPing fallback = constructLocalPing(connection.getProtocolVersion());
     List<CompletableFuture<ServerPing>> pings = new ArrayList<>();
     for (String s : servers) {
@@ -81,57 +84,118 @@ private CompletableFuture<ServerPing> attemptPingPassthrough(VelocityInboundConn
 
     CompletableFuture<List<ServerPing>> pingResponses = CompletableFutures.successfulAsList(pings,
         (ex) -> fallback);
-    switch (mode) {
-      case ALL:
-        return pingResponses.thenApply(responses -> {
-          // Find the first non-fallback
-          for (ServerPing response : responses) {
-            if (response == fallback) {
-              continue;
-            }
-            return response;
+    // Use the new ping passthrough mode if enabled.
+    if (mode.enabled()) {
+      return pingResponses.thenApply(responses -> {
+        // Find the first non-fallback. If it includes a modlist, add it too.
+        for (ServerPing response : responses) {
+          if (response == fallback) {
+            continue;
           }
-          return fallback;
-        });
-      case MODS:
-        return 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();
-            }
+
+          if (response.getDescriptionComponent() == null) {
+            continue;
           }
-          return fallback;
-        });
-      case DESCRIPTION:
-        return 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;
-            }
+          ServerPing.Version version;
+          if (mode.version) {
+            version = response.getVersion();
+          } else {
+            version = fallback.getVersion();
+          }
+
+          ServerPing.Players players;
+          if (mode.players) {
+            players = response.getPlayers().orElse(null);
+          } else {
+            players = fallback.getPlayers().orElse(null);
+          }
+
+          net.kyori.adventure.text.Component description;
+          if (mode.description) {
+            description = response.getDescriptionComponent();
+          } else {
+            description = fallback.getDescriptionComponent();
+          }
+
+          Favicon favicon;
+          if (mode.favicon) {
+            favicon = response.getFavicon().orElse(null);
+          } else {
+            favicon = fallback.getFavicon().orElse(null);
+          }
 
-            return new ServerPing(
-                fallback.getVersion(),
-                fallback.getPlayers().orElse(null),
-                response.getDescriptionComponent(),
-                fallback.getFavicon().orElse(null),
-                response.getModinfo().orElse(null)
-            );
+          ModInfo modinfo;
+          if (mode.modinfo) {
+            modinfo = response.getModinfo().orElse(null);
+          } else {
+            modinfo = fallback.getModinfo().orElse(null);
           }
-          return fallback;
-        });
-      // Not possible, but covered for completeness.
-      default:
-        return CompletableFuture.completedFuture(fallback);
+
+          return new ServerPing(
+              version,
+              players,
+              description,
+              favicon,
+              modinfo
+          );
+        }
+        return fallback;
+      });
+    } else {
+      // Otherwise, use the legacy ping passthrough mode.
+      switch (legacyMode) {
+        case ALL:
+          return pingResponses.thenApply(responses -> {
+            // Find the first non-fallback
+            for (ServerPing response : responses) {
+              if (response == fallback) {
+                continue;
+              }
+              return response;
+            }
+            return fallback;
+          });
+        case MODS:
+          return 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:
+          return 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(
+                  fallback.getVersion(),
+                  fallback.getPlayers().orElse(null),
+                  response.getDescriptionComponent(),
+                  fallback.getFavicon().orElse(null),
+                  response.getModinfo().orElse(null)
+              );
+            }
+            return fallback;
+          });
+        // Not possible, but covered for completeness.
+        default:
+          return CompletableFuture.completedFuture(fallback);
+      }
     }
   }
 
@@ -146,16 +210,17 @@ public CompletableFuture<ServerPing> getInitialPing(VelocityInboundConnection co
     ProtocolVersion shownVersion = connection.getProtocolVersion().isSupported()
         ? connection.getProtocolVersion() : ProtocolVersion.MAXIMUM_VERSION;
     PingPassthroughMode passthroughMode = configuration.getPingPassthrough();
+    LegacyPingPassthroughMode legacyPassthroughMode = configuration.getLegacyPingPassthrough();
 
-    if (passthroughMode == PingPassthroughMode.DISABLED) {
+    if (!passthroughMode.enabled() && legacyPassthroughMode == LegacyPingPassthroughMode.DISABLED) {
       return CompletableFuture.completedFuture(constructLocalPing(shownVersion));
     } else {
       String virtualHostStr = connection.getVirtualHost().map(InetSocketAddress::getHostString)
           .map(str -> str.toLowerCase(Locale.ROOT))
           .orElse("");
       List<String> serversToTry = server.getConfiguration().getForcedHosts().getOrDefault(
           virtualHostStr, server.getConfiguration().getAttemptConnectionOrder());
-      return attemptPingPassthrough(connection, passthroughMode, serversToTry, shownVersion);
+      return attemptPingPassthrough(connection, passthroughMode, legacyPassthroughMode, serversToTry, shownVersion);
     }
   }
 }

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

@@ -51,20 +51,23 @@ 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"
+# For the below options, the backend server Velocity contacts will be the first server that responds in the try list (or the forced host).
+# If no servers can be contacted, the Velocity configuration will be used instead.
+
+# Should Velocity send the version number from the backend server when responding to server list ping requests?
+ping-passthrough-version = false
+
+# Should Velocity send the player count from the backend server when responding to server list ping requests?
+ping-passthrough-players = false
+
+# Should Velocity send the description from the backend server when responding to server list ping requests?
+ping-passthrough-description = false
+
+# Should Velocity send the favicon (also known as the server icon) from the backend server when responding to server list ping requests?
+ping-passthrough-favicon = false
+
+# Should Velocity send the mod list from the backend server when responding to server list ping requests?
+ping-passthrough-modinfo = false
 
 # If not enabled (default is true) player IP addresses will be replaced by <ip address withheld> in logs
 enable-player-address-logging = true