Add Virtualhost support for server list pings

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

@@ -63,7 +63,7 @@ private ServerPing constructLocalPing(ProtocolVersion version) {
   }
 
   private CompletableFuture<ServerPing> attemptPingPassthrough(VelocityInboundConnection connection,
-      PingPassthroughMode mode, List<String> servers, ProtocolVersion responseProtocolVersion) {
+      PingPassthroughMode mode, List<String> servers, ProtocolVersion responseProtocolVersion, String virtualHostStr) {
     ServerPing fallback = constructLocalPing(connection.getProtocolVersion());
     List<CompletableFuture<ServerPing>> pings = new ArrayList<>();
     for (String s : servers) {
@@ -73,7 +73,7 @@ private CompletableFuture<ServerPing> attemptPingPassthrough(VelocityInboundConn
       }
       VelocityRegisteredServer vrs = (VelocityRegisteredServer) rs.get();
       pings.add(vrs.ping(connection.getConnection().eventLoop(), PingOptions.builder()
-              .version(responseProtocolVersion).build()));
+              .version(responseProtocolVersion).build(), virtualHostStr));
     }
     if (pings.isEmpty()) {
       return CompletableFuture.completedFuture(fallback);
@@ -155,7 +155,7 @@ public CompletableFuture<ServerPing> getInitialPing(VelocityInboundConnection co
           .orElse("");
       List<String> serversToTry = server.getConfiguration().getForcedHosts().getOrDefault(
           virtualHostStr, server.getConfiguration().getAttemptConnectionOrder());
-      return attemptPingPassthrough(connection, passthroughMode, serversToTry, shownVersion);
+      return attemptPingPassthrough(connection, passthroughMode, serversToTry, shownVersion, virtualHostStr);
     }
   }
 }

proxy/src/main/java/com/velocitypowered/proxy/server/PingSessionHandler.java

@@ -42,20 +42,22 @@ public class PingSessionHandler implements MinecraftSessionHandler {
   private final MinecraftConnection connection;
   private final ProtocolVersion version;
   private boolean completed = false;
+  private final String virtualHostString;
 
   PingSessionHandler(CompletableFuture<ServerPing> result, RegisteredServer server,
-      MinecraftConnection connection, ProtocolVersion version) {
+      MinecraftConnection connection, ProtocolVersion version, String virtualHostString) {
     this.result = result;
     this.server = server;
     this.connection = connection;
     this.version = version;
+    this.virtualHostString = virtualHostString;
   }
 
   @Override
   public void activated() {
     HandshakePacket handshake = new HandshakePacket();
     handshake.setNextStatus(StateRegistry.STATUS_ID);
-    handshake.setServerAddress(server.getServerInfo().getAddress().getHostString());
+    handshake.setServerAddress(this.virtualHostString.isEmpty() ? server.getServerInfo().getAddress().getHostString() : this.virtualHostString);
     handshake.setPort(server.getServerInfo().getAddress().getPort());
     handshake.setProtocolVersion(version);
     connection.delayedWrite(handshake);

proxy/src/main/java/com/velocitypowered/proxy/server/VelocityRegisteredServer.java

@@ -94,6 +94,10 @@ public CompletableFuture<ServerPing> ping() {
     return ping(null, PingOptions.DEFAULT);
   }
 
+  public CompletableFuture<ServerPing> ping(@Nullable EventLoop loop, PingOptions pingOptions) {
+    return ping(loop, pingOptions, "");
+  }
+
   /**
    * Pings the specified server using the specified event {@code loop}, claiming to be {@code
    * version}.
@@ -102,7 +106,7 @@ public CompletableFuture<ServerPing> ping() {
    * @param pingOptions the options to apply to this ping
    * @return the server list ping response
    */
-  public CompletableFuture<ServerPing> ping(@Nullable EventLoop loop, PingOptions pingOptions) {
+  public CompletableFuture<ServerPing> ping(@Nullable EventLoop loop, PingOptions pingOptions, String virtualHostString) {
     if (server == null) {
       throw new IllegalStateException("No Velocity proxy instance available");
     }
@@ -125,7 +129,7 @@ protected void initChannel(Channel ch) throws Exception {
       if (future.isSuccess()) {
         MinecraftConnection conn = future.channel().pipeline().get(MinecraftConnection.class);
         PingSessionHandler handler = new PingSessionHandler(pingFuture,
-            VelocityRegisteredServer.this, conn, pingOptions.getProtocolVersion());
+            VelocityRegisteredServer.this, conn, pingOptions.getProtocolVersion(), virtualHostString);
         conn.setActiveSessionHandler(StateRegistry.HANDSHAKE, handler);
       } else {
         pingFuture.completeExceptionally(future.cause());