Support forwarding bungeecord plugin channel to the ENTRY server. Bun…

…geecord PROXIES can now support direct connection from client.

Version 2.0.0

build.gradle

@@ -76,3 +76,8 @@ sourceSets.main.java.srcDir(generateTemplates.map { it.outputs })
 
 rootProject.idea.project.settings.taskTriggers.afterSync generateTemplates
 project.eclipse.synchronizationTasks(generateTemplates)
+
+tasks.withType(JavaCompile).configureEach {
+    options.encoding = "UTF-8"
+}
+

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

@@ -0,0 +1,42 @@
+package com.velocitypowered.proxy.connection.backend;
+
+import com.velocitypowered.proxy.VelocityServer;
+import com.velocitypowered.proxy.connection.client.ConnectedPlayer;
+import com.velocitypowered.proxy.protocol.packet.PluginMessage;
+import com.velocitypowered.proxy.protocol.util.ByteBufDataInput;
+import work.art1st.proxiedproxy.PPlugin;
+
+public class VBungeeCordMessageResponder extends BungeeCordMessageResponder {
+    private final VelocityServer proxy;
+    public VBungeeCordMessageResponder(VelocityServer proxy, ConnectedPlayer player) {
+        super(proxy, player);
+        this.proxy = proxy;
+    }
+
+    /* Send the PluginMessage to ENTRY */
+    @Override
+    boolean process(PluginMessage message) {
+        if (PPlugin.getProxyConfig().sendSwitchServerPluginMessageToEntry) {
+            ByteBufDataInput in = new ByteBufDataInput(message.content());
+            String subChannel = in.readUTF();
+            String target;
+            switch (subChannel) {
+                case "Connect":
+                case "ConnectOther":
+                    target = in.readUTF();
+                    if (this.proxy.getServer(target).isEmpty()) {
+                        return false;
+                    }
+                    break;
+                case "PlayerCount":
+                case "PlayerList":
+                    target = in.readUTF();
+                    if (!target.equals("ALL") && this.proxy.getServer(target).isEmpty()) {
+                        return false;
+                    }
+                    break;
+            }
+        }
+        return super.process(message);
+    }
+}

src/main/java/work/art1st/proxiedproxy/EventHandler.java

@@ -36,6 +36,10 @@ public void handleLoginPluginMessageResponse(PLoginPluginMessageResponseEvent ev
             String response = event.getMessage();
 
             ForwardingParser parser = event.getForwardingParser();
+            if (parser == null) {
+                loginInboundConnection.disconnect(Component.text("Invalid login packet: Can not parse profile data."));
+                return;
+            }
             /* Async callback function that stores forwarded player info into cache
              * The callback is always invoked before the next event (GameProfileRequestEvent). */
             PPlugin.debugOutput(response);

src/main/java/work/art1st/proxiedproxy/PPlugin.java

@@ -158,6 +158,7 @@ private static boolean doInitialize() throws IOException {
                 break;
             case PROXY:
                 proxyConfig.allowClientConnection = configFile.getOrElse("proxy.allow-client-connection", false);
+                proxyConfig.sendSwitchServerPluginMessageToEntry = configFile.getOrElse("proxy.send-switch-server-plugin-message-to-entry", true);
                 try {
                     proxyConfig.skinServiceBackendVerifier = new SkinServiceBackendVerifier(
                             configFile.getOrElse("proxy.skin-service-backend.allowed", new ArrayList<>()),

src/main/java/work/art1st/proxiedproxy/config/ProxyConfig.java

@@ -24,4 +24,5 @@ public class ProxyConfig {
             .expireAfterAccess(FORWARDING_PACKET_TIMEOUT + 5, TimeUnit.SECONDS)
             .build();
     public SkinServiceBackendVerifier skinServiceBackendVerifier;
+    public boolean sendSwitchServerPluginMessageToEntry;
 }

src/main/java/work/art1st/proxiedproxy/platform/bungeecord/BungeeEventListener.java

@@ -1,13 +1,20 @@
 package work.art1st.proxiedproxy.platform.bungeecord;
 
 import lombok.SneakyThrows;
+import net.md_5.bungee.BungeeCord;
+import net.md_5.bungee.UserConnection;
 import net.md_5.bungee.api.event.PostLoginEvent;
 import net.md_5.bungee.api.event.PreLoginEvent;
+import net.md_5.bungee.api.event.ServerSwitchEvent;
 import net.md_5.bungee.api.plugin.Listener;
 import net.md_5.bungee.event.EventHandler;
+import net.md_5.bungee.netty.ChannelWrapper;
+import net.md_5.bungee.netty.HandlerBoss;
 import work.art1st.proxiedproxy.PPlugin;
+import work.art1st.proxiedproxy.platform.bungeecord.connection.BDownstreamBridge;
 import work.art1st.proxiedproxy.platform.bungeecord.event.BPostLoginEvent;
 import work.art1st.proxiedproxy.platform.bungeecord.event.BPreLoginEvent;
+import work.art1st.proxiedproxy.util.ReflectUtil;
 
 public class BungeeEventListener implements Listener {
     @SneakyThrows
@@ -20,4 +27,13 @@ public void onPreLogin(PreLoginEvent event) {
     public void onPostLogin(PostLoginEvent event) {
         PPlugin.getEventHandler().handlePostLogin(new BPostLoginEvent(event));
     }
+
+    @SneakyThrows
+    @EventHandler
+    public void onServerSwitchEvent(ServerSwitchEvent event) {
+        UserConnection userConnection = (UserConnection) event.getPlayer();
+        ChannelWrapper ch = ReflectUtil.getDeclaredFieldValue(userConnection, "ch");
+        BungeeCord bungee = ReflectUtil.getDeclaredFieldValue(userConnection, "bungee");
+        ch.getHandle().pipeline().get(HandlerBoss.class).setHandler(new BDownstreamBridge(bungee, userConnection, userConnection.getServer()));
+    }
 }

src/main/java/work/art1st/proxiedproxy/platform/bungeecord/connection/BDownstreamBridge.java

@@ -0,0 +1,51 @@
+package work.art1st.proxiedproxy.platform.bungeecord.connection;
+
+import com.google.common.io.ByteArrayDataOutput;
+import com.google.common.io.ByteStreams;
+import net.md_5.bungee.ServerConnection;
+import net.md_5.bungee.UserConnection;
+import net.md_5.bungee.api.ProxyServer;
+import net.md_5.bungee.connection.DownstreamBridge;
+import net.md_5.bungee.protocol.packet.PluginMessage;
+import work.art1st.proxiedproxy.PPlugin;
+
+import java.io.DataInput;
+
+public class BDownstreamBridge extends DownstreamBridge {
+    private final ProxyServer bungee;
+    public BDownstreamBridge(ProxyServer bungee, UserConnection con, ServerConnection server) {
+        super(bungee, con, server);
+        this.bungee = bungee;
+    }
+
+    /* Send the PluginMessage to ENTRY */
+    @Override
+    @SuppressWarnings("checkstyle:avoidnestedblocks")
+    public void handle(PluginMessage pluginMessage) throws Exception
+    {
+        if (PPlugin.getProxyConfig().sendSwitchServerPluginMessageToEntry) {
+            DataInput in = pluginMessage.getStream();
+            if (pluginMessage.getTag().equals("BungeeCord")) {
+                String subChannel = in.readUTF();
+                String target;
+                switch (subChannel) {
+                    case "Connect":
+                    case "ConnectOther":
+                        target = in.readUTF();
+                        if (this.bungee.getServerInfo(target) == null) {
+                            return;
+                        }
+                        break;
+                    case "PlayerCount":
+                    case "PlayerList":
+                        target = in.readUTF();
+                        if (!target.equals("ALL") && this.bungee.getServerInfo(target) == null) {
+                            return;
+                        }
+                        break;
+                }
+            }
+        }
+        super.handle(pluginMessage);
+    }
+}

src/main/java/work/art1st/proxiedproxy/platform/bungeecord/connection/BLoginInboundConnection.java

@@ -22,10 +22,11 @@ public final class BLoginInboundConnection implements PLoginInboundConnection {
     private final Callback<PreLoginEvent> origEventCallBack;
     private PreLoginEvent cb_args_result;
     private Throwable cb_args_error;
+    private final boolean isDirectConnection;
     @SneakyThrows
     public BLoginInboundConnection(PreLoginEvent preLoginEvent) {
-        this.handler = (InitialHandler) preLoginEvent.getConnection();
-        this.ch = ReflectUtil.getDeclaredFieldValue(handler, "ch");
+        handler = (InitialHandler) preLoginEvent.getConnection();
+        ch = ReflectUtil.getDeclaredFieldValue(handler, "ch");
         Field doneField = AsyncEvent.class.getDeclaredField("done");
         ReflectUtil.handleAccessible(doneField);
         origEventCallBack = (Callback<PreLoginEvent>) doneField.get(preLoginEvent);
@@ -34,6 +35,7 @@ public BLoginInboundConnection(PreLoginEvent preLoginEvent) {
             cb_args_error = error;
         };
         doneField.set(preLoginEvent, modifiedCallback);
+        isDirectConnection = isVHostFromClient(handler.getVirtualHost(), handler.getHandshake().getHost());
     }
 
     @Override
@@ -44,7 +46,7 @@ public void sendLoginPluginMessage(String contents) {
 
     @Override
     public boolean isDirectConnection() {
-        return false;
+        return isDirectConnection;
     }
 
     @SneakyThrows

src/main/java/work/art1st/proxiedproxy/platform/common/connection/PLoginInboundConnection.java

@@ -2,10 +2,25 @@
 
 import net.kyori.adventure.text.Component;
 
+import java.net.InetSocketAddress;
+import java.util.Locale;
+
 public interface PLoginInboundConnection {
     void sendLoginPluginMessage(String message);
     boolean isDirectConnection();
     /** Should only affect the effect of functions like "getRemoteAddress", not the address of the actual connection. */
     void setRemoteAddress(String remoteAddress);
     void disconnect(Component reason);
+    default boolean isVHostFromClient(InetSocketAddress address, String vHostValue) {
+        String cleanedAddress = address == null ? "" : address.getHostString().toLowerCase(Locale.ROOT);
+        String origAddress = vHostValue.toLowerCase(Locale.ROOT);
+        if (!origAddress.isEmpty() && origAddress.charAt(origAddress.length() - 1) == '.') {
+            origAddress = origAddress.substring(0, origAddress.length() - 1);
+        }
+        return !(!cleanedAddress.equals(origAddress)
+                && !origAddress.endsWith("\0fml\0")
+                && !origAddress.endsWith("\0fml2\0")
+                && !origAddress.endsWith("\0fml3\0")
+                && !origAddress.endsWith("\0fml4\0"));
+    }
 }

src/main/java/work/art1st/proxiedproxy/platform/velocity/VelocityMain.java

@@ -7,12 +7,17 @@
 import com.velocitypowered.api.event.connection.PreLoginEvent;
 import com.velocitypowered.api.event.player.GameProfileRequestEvent;
 import com.velocitypowered.api.event.player.ServerLoginPluginMessageEvent;
+import com.velocitypowered.api.event.player.ServerPostConnectEvent;
 import com.velocitypowered.api.event.proxy.ProxyInitializeEvent;
 import com.velocitypowered.api.plugin.annotation.DataDirectory;
 import com.velocitypowered.api.proxy.ProxyServer;
 import com.velocitypowered.proxy.VelocityServer;
 import com.velocitypowered.proxy.config.PlayerInfoForwarding;
 import com.velocitypowered.proxy.config.VelocityConfiguration;
+import com.velocitypowered.proxy.connection.MinecraftConnection;
+import com.velocitypowered.proxy.connection.backend.BackendPlaySessionHandler;
+import com.velocitypowered.proxy.connection.backend.VBungeeCordMessageResponder;
+import com.velocitypowered.proxy.connection.backend.VelocityServerConnection;
 import com.velocitypowered.proxy.connection.client.LoginInboundConnection;
 import com.velocitypowered.proxy.connection.util.ServerListPingHandler;
 import lombok.Getter;
@@ -115,6 +120,19 @@ public void onServerLoginPluginMessage(ServerLoginPluginMessageEvent event) {
         }
     }
 
+    @SneakyThrows
+    @Subscribe
+    public void onServerPostConnection(ServerPostConnectEvent event) {
+        if (event.getPlayer().getCurrentServer().isPresent()) {
+            VelocityServerConnection serverConnection = (VelocityServerConnection) event.getPlayer().getCurrentServer().get();
+            MinecraftConnection clientConnection = serverConnection.ensureConnected();
+            BackendPlaySessionHandler sessionHandler = (BackendPlaySessionHandler) clientConnection.getSessionHandler();
+            assert sessionHandler != null;
+            ReflectUtil.setDeclaredFieldValue(sessionHandler, "bungeecordMessageResponder",
+                    new VBungeeCordMessageResponder(sessionHandler.getServer(), serverConnection.getPlayer()));
+        }
+    }
+
     @Override
     public boolean configCheck() {
         if (proxy.getConfiguration() instanceof VelocityConfiguration) {

src/main/java/work/art1st/proxiedproxy/platform/velocity/connection/VLoginInboundConnection.java

@@ -22,18 +22,15 @@ public final class VLoginInboundConnection implements PLoginInboundConnection {
 
     public VLoginInboundConnection(LoginInboundConnection connection) {
         vConnection = connection;
-        String cleanedAddress = vConnection.getVirtualHost().map(InetSocketAddress::getHostString).map(str -> str.toLowerCase(Locale.ROOT)).orElse("");
+        InetSocketAddress address = vConnection.getVirtualHost().orElse(null);
         String origAddress;
         try {
             origAddress = getServerAddressFromConnection(vConnection).toLowerCase(Locale.ROOT);
         } catch (NoSuchFieldException | IllegalAccessException e) {
             vConnection.disconnect(Component.text("Invalid connection."));
             throw new RuntimeException(e);
         }
-        if (!origAddress.isEmpty() && origAddress.charAt(origAddress.length() - 1) == '.') {
-            origAddress = origAddress.substring(0, origAddress.length() - 1);
-        }
-        isDirectConnection = !(!cleanedAddress.equals(origAddress) && !origAddress.endsWith("\0fml\0") && !origAddress.endsWith("\0fml2\0") && !origAddress.endsWith("\0fml3\0") && !origAddress.endsWith("\0fml4\0"));
+        isDirectConnection = isVHostFromClient(address, origAddress);
     }
     private static String getServerAddressFromConnection(LoginInboundConnection inbound) throws NoSuchFieldException, IllegalAccessException {
         //Field delegateField = ReflectUtil.handleAccessible(inbound.getClass().getDeclaredField("delegate"));

src/main/resources/config-entry.toml

@@ -7,18 +7,18 @@ verbose = false
 
 # Contents below are valid for ENTRY servers
 [entry]
-# Replace /server with your custom command.
-server-command-alias = "hub"
-# Available options:
-# - RSA: Prefered
-# - KEY
-# Downstream PROXIES should add contents in generated entry.json to their TrustedEntries.json list.
-# entry.json is just a generated file for you to conveniently send it to the downstream PROXIES, modifications have no effect.
-verification-type = "RSA"
-entry-id = ""
-pass-through-ping-vhost = true
-send-v1-verification = false
+    # Replace /server with your custom command.
+    server-command-alias = "hub"
+    # Available options:
+    # - RSA: Prefered
+    # - KEY
+    # Downstream PROXIES should add contents in generated entry.json to their TrustedEntries.json list.
+    # entry.json is just a generated file for you to conveniently send it to the downstream PROXIES, modifications have no effect.
+    verification-type = "RSA"
+    entry-id = ""
+    pass-through-ping-vhost = true
+    send-v1-verification = false
 
-[entry.key]
-# Valid if verification-type is set to "KEY"
-key = ""
+        [entry.key]
+            # Valid if verification-type is set to "KEY"
+            key = ""

src/main/resources/config-proxy.toml

@@ -8,12 +8,15 @@ verbose = false
 
 # Contents below are valid for PROXY servers
 [proxy]
-# Set to false to disable connection from clients.
-allow-client-connection = false
+    # Set to true to enable clients directly connecting to the server.
+    allow-client-connection = false
+    # Set to
+    send-switch-server-plugin-message-to-entry = true
 
-[proxy.skin-service-backend]
-# Both empty: Disabled
-# Both not empty: Will work only in whitelist mode
-blocked = []
-allowed = []
-union-query-api = "https://skin.mualliance.ltd/api/union/profile/mapped/byuuid/"
+    [proxy.skin-service-backend]
+        # Both empty: Disabled
+        # Both not empty: Will work only in whitelist mode
+        # Note: If enabled, the plugin will also check the skin server of directly connected players.
+        blocked = []
+        allowed = []
+        union-query-api = "https://skin.mualliance.ltd/api/union/profile/mapped/byuuid/"