Fix missing group members on 2.5 clients

README.md

@@ -10,8 +10,12 @@ The plugin is compiled to Java 8 bytecode and runs on newer JVMs.
 The server negotiates the protocol generation during the existing voice-chat
 handshake and stores it with that player's 16-byte secret. The UDP path then
 uses AES-CBC for 2.5 clients and AES-GCM for 2.6 clients. Shared packet layouts
-are passed through the existing 2.6 voice routing. The fork changes only the
-per-client cipher selection and compatibility-version acceptance.
+are passed through the existing 2.6 voice routing. State messages are sent on
+the channel names expected by each client generation, so 2.5 clients receive
+their player and group-member updates as well. For compatibility 18 the server
+maps `voicechat:state` and `voicechat:states` to the older
+`voicechat:player_state` and `voicechat:player_states` channels. When a player
+leaves, it sends the disconnected state because 2.5 has no remove-state packet.
 
 The Bukkit plugin source and API source are in `source/bukkit/` and
 `source/api/`. The cipher and compatibility changes are in the regular source

source/bukkit/src/main/java/de/maxhenkel/voicechat/command/VoiceChatCommands.java

@@ -112,6 +112,8 @@ public class VoiceChatCommands implements CommandExecutor, TabCompleter {
             return true;
         }
 
+        int clientCompatibilityVersion = Voicechat.SERVER.getClientCompatibilityVersion(player.getUniqueId());
+
         ClientConnection clientConnection = Voicechat.SERVER.getServer().getConnections().get(player.getUniqueId());
 
         if (clientConnection == null) {
@@ -130,6 +132,8 @@ public class VoiceChatCommands implements CommandExecutor, TabCompleter {
                     } else {
                         NetManager.sendMessage(commandSender, "message.voicechat.ping_received_attempt", String.valueOf(pingMilliseconds), String.valueOf(attempts));
                     }
+                    commandSender.sendMessage("Voice chat connection verified (client compatibility version "
+                            + clientCompatibilityVersion + ").");
                 }
 
                 @Override

source/bukkit/src/main/java/de/maxhenkel/voicechat/net/NetManager.java

@@ -38,6 +38,9 @@ public class NetManager implements Listener {
             registerOutgoingPacket(JoinedGroupPacket.class);
             registerOutgoingPacket(AddCategoryPacket.class);
             registerOutgoingPacket(RemoveCategoryPacket.class);
+
+            registerOutgoingChannel(ProtocolChannelCompatibility.LEGACY_PLAYER_STATE);
+            registerOutgoingChannel(ProtocolChannelCompatibility.LEGACY_PLAYER_STATES);
         } catch (Exception e) {
             throw new IllegalStateException("Failed to register voice chat packets", e);
         }
@@ -100,6 +103,10 @@ public class NetManager implements Listener {
 
     private <T extends Packet<?>> void registerOutgoingPacket(Class<T> packetClass) throws NoSuchMethodException, InvocationTargetException, InstantiationException, IllegalAccessException {
         String id = packetClass.getDeclaredConstructor().newInstance().getID().toString();
+        registerOutgoingChannel(id);
+    }
+
+    private void registerOutgoingChannel(String id) {
         packets.add(id);
         Bukkit.getMessenger().registerOutgoingPluginChannel(Voicechat.INSTANCE, id);
     }
@@ -114,7 +121,11 @@ public class NetManager implements Listener {
                 p.toBytes(buf);
                 byte[] bytes = new byte[buf.readableBytes()];
                 buf.readBytes(bytes);
-                player.sendPluginMessage(Voicechat.INSTANCE, p.getID().toString(), bytes);
+                int compatibilityVersion = Voicechat.SERVER.getClientCompatibilityVersion(player.getUniqueId());
+                String channel = ProtocolChannelCompatibility.outgoingChannel(p.getID().toString(), compatibilityVersion);
+                if (channel != null) {
+                    player.sendPluginMessage(Voicechat.INSTANCE, channel, bytes);
+                }
             } catch (Exception e) {
                 Voicechat.LOGGER.error("Failed to send packet to '{}'", player.getName(), e);
             }

source/bukkit/src/main/java/de/maxhenkel/voicechat/net/ProtocolChannelCompatibility.java

@@ -0,0 +1,27 @@
+package de.maxhenkel.voicechat.net;
+
+public final class ProtocolChannelCompatibility {
+    public static final int LEGACY_COMPATIBILITY_VERSION = 18;
+
+    public static final String LEGACY_PLAYER_STATE = "voicechat:player_state";
+    public static final String LEGACY_PLAYER_STATES = "voicechat:player_states";
+
+    private ProtocolChannelCompatibility() {
+    }
+
+    public static String outgoingChannel(String channel, int compatibilityVersion) {
+        if (compatibilityVersion != LEGACY_COMPATIBILITY_VERSION) {
+            return channel;
+        }
+        switch (channel) {
+            case "voicechat:state":
+                return LEGACY_PLAYER_STATE;
+            case "voicechat:states":
+                return LEGACY_PLAYER_STATES;
+            case "voicechat:remove_state":
+                return null;
+            default:
+                return channel;
+        }
+    }
+}

source/bukkit/src/main/java/de/maxhenkel/voicechat/voice/server/PlayerStateManager.java

@@ -56,8 +56,7 @@ public class PlayerStateManager implements Listener {
     }
 
     public void onPlayerHide(PlayerHideEvent event) {
-        RemovePlayerStatePacket packet = new RemovePlayerStatePacket(event.getHiddenPlayer().getUniqueId());
-        NetManager.sendToClient(event.getObserver(), packet);
+        sendRemoveState(event.getObserver(), event.getHiddenPlayer());
         Voicechat.LOGGER.debug("Removing state of {} for {}", event.getHiddenPlayer().getName(), event.getObserver().getName());
     }
 
@@ -83,14 +82,22 @@ public class PlayerStateManager implements Listener {
     }
 
     public void broadcastRemoveState(Player stateOwner) {
-        RemovePlayerStatePacket packet = new RemovePlayerStatePacket(stateOwner.getUniqueId());
         for (Player receiver : Voicechat.INSTANCE.getServer().getOnlinePlayers()) {
-            NetManager.sendToClient(receiver, packet);
+            sendRemoveState(receiver, stateOwner);
         }
         // Send the default disconnected state to the API when disconnecting
         PluginManager.instance().onPlayerStateChanged(defaultDisconnectedState(stateOwner));
     }
 
+    private void sendRemoveState(Player receiver, Player stateOwner) {
+        if (Voicechat.SERVER.getClientCompatibilityVersion(receiver.getUniqueId())
+                == de.maxhenkel.voicechat.net.ProtocolChannelCompatibility.LEGACY_COMPATIBILITY_VERSION) {
+            NetManager.sendToClient(receiver, new PlayerStatePacket(defaultDisconnectedState(stateOwner)));
+            return;
+        }
+        NetManager.sendToClient(receiver, new RemovePlayerStatePacket(stateOwner.getUniqueId()));
+    }
+
     public void onPlayerCompatibilityCheckSucceeded(Player player) {
         List<PlayerState> stateList = new ArrayList<>(states.size());
         for (PlayerState state : states.values()) {

source/bukkit/src/main/java/de/maxhenkel/voicechat/voice/server/ServerVoiceEvents.java

@@ -83,6 +83,10 @@ public class ServerVoiceEvents implements Listener {
         return isSupportedCompatibilityVersion(clientCompatibilities.getOrDefault(playerUuid, -1));
     }
 
+    public int getClientCompatibilityVersion(UUID playerUuid) {
+        return clientCompatibilities.getOrDefault(playerUuid, -1);
+    }
+
     public static void sendIncompatibleMessage(Player player, int clientCompatibilityVersion) {
         if (clientCompatibilityVersion <= 6) {
             player.sendMessage(String.format(Voicechat.TRANSLATIONS.voicechatNotCompatibleMessage.get(),

tests/ProtocolCryptoSelfTest.java

@@ -1,4 +1,5 @@
 import de.maxhenkel.voicechat.voice.common.Secret;
+import de.maxhenkel.voicechat.net.ProtocolChannelCompatibility;
 import java.nio.ByteBuffer;
 import java.security.SecureRandom;
 import java.util.Arrays;
@@ -9,6 +10,8 @@ import javax.crypto.spec.SecretKeySpec;
 
 public class ProtocolCryptoSelfTest {
     public static void main(String[] args) throws Exception {
+        testStateChannelCompatibility();
+
         byte[] key = new byte[16];
         for (int i = 0; i < key.length; i++) key[i] = (byte) (i * 13 + 7);
         UUID legacyKey = uuidFromBytes(key);
@@ -34,7 +37,23 @@ public class ProtocolCryptoSelfTest {
                 throw new AssertionError("Hybrid server AES-GCM round-trip failed");
             }
         }
-        System.out.println("PASS: 100 CBC client/server interop cycles and 100 GCM round-trips");
+        System.out.println("PASS: legacy state-channel mapping, 100 CBC interop cycles and 100 GCM round-trips");
+    }
+
+    private static void testStateChannelCompatibility() {
+        check("voicechat:player_state", ProtocolChannelCompatibility.outgoingChannel("voicechat:state", 18));
+        check("voicechat:player_states", ProtocolChannelCompatibility.outgoingChannel("voicechat:states", 18));
+        if (ProtocolChannelCompatibility.outgoingChannel("voicechat:remove_state", 18) != null) {
+            throw new AssertionError("The 2.5 client has no remove-state packet");
+        }
+        check("voicechat:state", ProtocolChannelCompatibility.outgoingChannel("voicechat:state", 20));
+        check("voicechat:states", ProtocolChannelCompatibility.outgoingChannel("voicechat:states", 20));
+    }
+
+    private static void check(String expected, String actual) {
+        if (!expected.equals(actual)) {
+            throw new AssertionError("Expected channel " + expected + ", got " + actual);
+        }
     }
 
     private static UUID uuidFromBytes(byte[] bytes) {