Allow setting forwarding mode separately for different servers

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

@@ -70,7 +70,7 @@ public class VelocityConfiguration implements ProxyConfig {
   @Expose
   private boolean preventClientProxyConnections = false;
   @Expose
-  private PlayerInfoForwarding playerInfoForwardingMode = PlayerInfoForwarding.NONE;
+  private PlayerInfoForwarding defaultForwardingMode = PlayerInfoForwarding.NONE;
   private byte[] forwardingSecret = generateRandomString(12).getBytes(StandardCharsets.UTF_8);
   @Expose
   private boolean announceForge = false;
@@ -103,7 +103,7 @@ private VelocityConfiguration(Servers servers, ForcedHosts forcedHosts, Advanced
 
   private VelocityConfiguration(String bind, String motd, int showMaxPlayers, boolean onlineMode,
       boolean preventClientProxyConnections, boolean announceForge,
-      PlayerInfoForwarding playerInfoForwardingMode, byte[] forwardingSecret,
+      PlayerInfoForwarding defaultForwardingMode, byte[] forwardingSecret,
       boolean onlineModeKickExistingPlayers, PingPassthroughMode pingPassthrough,
       boolean enablePlayerAddressLogging, Servers servers, ForcedHosts forcedHosts,
       Advanced advanced, Query query, Metrics metrics, boolean forceKeyAuthentication) {
@@ -113,7 +113,7 @@ private VelocityConfiguration(String bind, String motd, int showMaxPlayers, bool
     this.onlineMode = onlineMode;
     this.preventClientProxyConnections = preventClientProxyConnections;
     this.announceForge = announceForge;
-    this.playerInfoForwardingMode = playerInfoForwardingMode;
+    this.defaultForwardingMode = defaultForwardingMode;
     this.forwardingSecret = forwardingSecret;
     this.onlineModeKickExistingPlayers = onlineModeKickExistingPlayers;
     this.pingPassthrough = pingPassthrough;
@@ -151,22 +151,41 @@ public boolean validate() {
           + "receive any support!");
     }
 
-    switch (playerInfoForwardingMode) {
+    boolean requireForwardingSecret = false;
+    for (Map.Entry<String, PlayerInfoForwarding> entry : servers.getServerForwardingModes().entrySet()) {
+      switch (entry.getValue()) {
+        case NONE:
+          logger.warn("Player info forwarding is disabled for {}!"
+              + " All players will appear to be connecting from the proxy and will have offline-mode UUIDs.", entry.getKey());
+          break;
+        case MODERN:
+        case BUNGEEGUARD:
+          requireForwardingSecret = true;
+          break;
+        default:
+          break;
+      }
+    }
+
+    switch (defaultForwardingMode) {
       case NONE:
-        logger.warn("Player info forwarding is disabled! All players will appear to be connecting "
+        logger.warn("Player info forwarding is disabled by default! All players will appear to be connecting "
             + "from the proxy and will have offline-mode UUIDs.");
         break;
       case MODERN:
       case BUNGEEGUARD:
-        if (forwardingSecret == null || forwardingSecret.length == 0) {
-          logger.error("You don't have a forwarding secret set. This is required for security.");
-          valid = false;
-        }
+        requireForwardingSecret = true;
         break;
       default:
         break;
     }
 
+    if (requireForwardingSecret && (forwardingSecret == null || forwardingSecret.length == 0)) {
+      logger.error("You don't have a forwarding secret set. This is required for security. "
+          + "See https://docs.papermc.io/velocity/player-information-forwarding#configuring-modern-forwarding for more details.");
+      valid = false;
+    }
+
     if (servers.getServers().isEmpty()) {
       logger.warn("You don't have any servers configured.");
     }
@@ -293,8 +312,12 @@ public boolean shouldPreventClientProxyConnections() {
     return preventClientProxyConnections;
   }
 
-  public PlayerInfoForwarding getPlayerInfoForwardingMode() {
-    return playerInfoForwardingMode;
+  public PlayerInfoForwarding getDefaultForwardingMode() {
+    return defaultForwardingMode;
+  }
+
+  public PlayerInfoForwarding getServerForwardingMode(String server) {
+    return servers.getServerForwardingModes().getOrDefault(server, defaultForwardingMode);
   }
 
   public byte[] getForwardingSecret() {
@@ -414,7 +437,7 @@ public String toString() {
         .add("motd", motd)
         .add("showMaxPlayers", showMaxPlayers)
         .add("onlineMode", onlineMode)
-        .add("playerInfoForwardingMode", playerInfoForwardingMode)
+        .add("defaultForwardingMode", defaultForwardingMode)
         .add("forwardingSecret", forwardingSecret)
         .add("announceForge", announceForge)
         .add("servers", servers)
@@ -572,16 +595,33 @@ private static class Servers {
         "minigames", "127.0.0.1:30068"
     );
     private List<String> attemptConnectionOrder = ImmutableList.of("lobby");
+    private Map<String, PlayerInfoForwarding> serverForwardingModes = ImmutableMap.of();
 
     private Servers() {
     }
 
     private Servers(CommentedConfig config) {
       if (config != null) {
         Map<String, String> servers = new HashMap<>();
+        Map<String, PlayerInfoForwarding> serverForwardingModes = new HashMap<>();
         for (UnmodifiableConfig.Entry entry : config.entrySet()) {
           if (entry.getValue() instanceof String) {
             servers.put(cleanServerName(entry.getKey()), entry.getValue());
+          } else if (entry.getValue() instanceof UnmodifiableConfig) {
+            UnmodifiableConfig unmodifiableConfig = entry.getValue();
+            String name = entry.getKey();
+
+            String address = unmodifiableConfig.get("address");
+            if (address == null) {
+              throw new IllegalArgumentException("Server " + name + " doesn't have an address!");
+            }
+
+            PlayerInfoForwarding mode = unmodifiableConfig.getEnum("forwarding-mode", PlayerInfoForwarding.class);
+            if (mode != null) {
+              serverForwardingModes.put(name, mode);
+            }
+
+            servers.put(name, address);
           } else {
             if (!entry.getKey().equalsIgnoreCase("try")) {
               throw new IllegalArgumentException(
@@ -591,12 +631,14 @@ private Servers(CommentedConfig config) {
         }
         this.servers = ImmutableMap.copyOf(servers);
         this.attemptConnectionOrder = config.getOrElse("try", attemptConnectionOrder);
+        this.serverForwardingModes = ImmutableMap.copyOf(serverForwardingModes);
       }
     }
 
-    private Servers(Map<String, String> servers, List<String> attemptConnectionOrder) {
+    private Servers(Map<String, String> servers, List<String> attemptConnectionOrder, Map<String, PlayerInfoForwarding> serverForwardingModes) {
       this.servers = servers;
       this.attemptConnectionOrder = attemptConnectionOrder;
+      this.serverForwardingModes = serverForwardingModes;
     }
 
     private Map<String, String> getServers() {
@@ -615,6 +657,14 @@ public void setAttemptConnectionOrder(List<String> attemptConnectionOrder) {
       this.attemptConnectionOrder = attemptConnectionOrder;
     }
 
+    public Map<String, PlayerInfoForwarding> getServerForwardingModes() {
+      return serverForwardingModes;
+    }
+
+    public void setServerForwardingModes(Map<String, PlayerInfoForwarding> serverForwardingModes) {
+      this.serverForwardingModes = serverForwardingModes;
+    }
+
     /**
      * TOML requires keys to match a regex of {@code [A-Za-z0-9_-]} unless it is wrapped in quotes;
      * however, the TOML parser returns the key with the quotes so we need to clean the server name
@@ -632,6 +682,7 @@ public String toString() {
       return "Servers{"
           + "servers=" + servers
           + ", attemptConnectionOrder=" + attemptConnectionOrder
+          + ", serverForwardingModes=" + serverForwardingModes
           + '}';
     }
   }

proxy/src/main/java/com/velocitypowered/proxy/connection/backend/LoginSessionHandler.java

@@ -83,7 +83,7 @@ public boolean handle(EncryptionRequestPacket packet) {
   public boolean handle(LoginPluginMessagePacket packet) {
     MinecraftConnection mc = serverConn.ensureConnected();
     VelocityConfiguration configuration = server.getConfiguration();
-    if (configuration.getPlayerInfoForwardingMode() == PlayerInfoForwarding.MODERN
+    if (configuration.getServerForwardingMode(serverConn.getServerInfo().getName()) == PlayerInfoForwarding.MODERN
         && packet.getChannel().equals(PlayerDataForwarding.CHANNEL)) {
 
       int requestedForwardingVersion = PlayerDataForwarding.MODERN_DEFAULT;
@@ -143,7 +143,8 @@ public boolean handle(SetCompressionPacket packet) {
 
   @Override
   public boolean handle(ServerLoginSuccessPacket packet) {
-    if (server.getConfiguration().getPlayerInfoForwardingMode() == PlayerInfoForwarding.MODERN && !informationForwarded) {
+    if (server.getConfiguration().getServerForwardingMode(serverConn.getServerInfo().getName()) == PlayerInfoForwarding.MODERN
+        && !informationForwarded) {
       resultFuture.complete(ConnectionRequestResults.forDisconnect(MODERN_IP_FORWARDING_FAILURE, serverConn.getServer()));
       serverConn.disconnect();
       return true;
@@ -202,7 +203,7 @@ public void exception(Throwable throwable) {
 
   @Override
   public void disconnected() {
-    if (server.getConfiguration().getPlayerInfoForwardingMode() == PlayerInfoForwarding.LEGACY) {
+    if (server.getConfiguration().getServerForwardingMode(serverConn.getServerInfo().getName()) == PlayerInfoForwarding.LEGACY) {
       resultFuture.completeExceptionally(new QuietRuntimeException(
               """
               The connection to the remote server was unexpectedly closed.

proxy/src/main/java/com/velocitypowered/proxy/connection/backend/VelocityServerConnection.java

@@ -163,7 +163,7 @@ private String createBungeeGuardForwardingAddress(byte[] forwardingSecret) {
 
   private void startHandshake() {
     final MinecraftConnection mc = ensureConnected();
-    PlayerInfoForwarding forwardingMode = server.getConfiguration().getPlayerInfoForwardingMode();
+    PlayerInfoForwarding forwardingMode = server.getConfiguration().getServerForwardingMode(registeredServer.getServerInfo().getName());
 
     // Initiate the handshake.
     ProtocolVersion protocolVersion = proxyPlayer.getConnection().getProtocolVersion();

proxy/src/main/java/com/velocitypowered/proxy/connection/client/AuthSessionHandler.java

@@ -83,7 +83,7 @@ public class AuthSessionHandler implements MinecraftSessionHandler {
   public void activated() {
     // Some connection types may need to alter the game profile.
     profile = mcConnection.getType().addGameProfileTokensIfRequired(profile,
-        server.getConfiguration().getPlayerInfoForwardingMode());
+        server.getConfiguration().getDefaultForwardingMode());
     GameProfileRequestEvent profileRequestEvent = new GameProfileRequestEvent(inbound, profile,
         onlineMode);
     final GameProfile finalProfile = profile;
@@ -139,7 +139,7 @@ private void startLoginCompletion(ConnectedPlayer player) {
     }
     VelocityConfiguration configuration = server.getConfiguration();
     UUID playerUniqueId = player.getUniqueId();
-    if (configuration.getPlayerInfoForwardingMode() == PlayerInfoForwarding.NONE) {
+    if (configuration.getDefaultForwardingMode() == PlayerInfoForwarding.NONE) {
       playerUniqueId = UuidUtils.generateOfflinePlayerUuid(player.getUsername());
     }
 

proxy/src/main/java/com/velocitypowered/proxy/connection/client/HandshakeSessionHandler.java

@@ -146,7 +146,7 @@ private void handleLogin(HandshakePacket handshake, InitialInboundConnection ic)
 
     // If the proxy is configured for modern forwarding, we must deny connections from 1.12.2
     // and lower, otherwise IP information will never get forwarded.
-    if (server.getConfiguration().getPlayerInfoForwardingMode() == PlayerInfoForwarding.MODERN
+    if (server.getConfiguration().getDefaultForwardingMode() == PlayerInfoForwarding.MODERN
         && handshake.getProtocolVersion().lessThan(ProtocolVersion.MINECRAFT_1_13)) {
       // Bump connection into correct protocol state so that we can send the disconnect packet.
       connection.setState(StateRegistry.LOGIN);

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

@@ -42,7 +42,7 @@ 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"
 # instead for a nicer display in the server list.
 announce-forge = false
@@ -76,6 +76,9 @@ lobby = "127.0.0.1:30066"
 factions = "127.0.0.1:30067"
 minigames = "127.0.0.1:30068"
 
+# If you need a different forwarding mode, specify it like this
+modern = { address = "127.0.0.1:30069", forwarding-mode = "MODERN" }
+
 # In what order we should try servers when a player logs in or is kicked from a server.
 try = [
     "lobby"