Remove filter checks to receive PluginMessages unfiltered.

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

@@ -34,6 +34,8 @@ import com.velocitypowered.api.event.player.ServerResourcePackSendEvent;
 import com.velocitypowered.api.event.proxy.ProxyPingEvent;
 import com.velocitypowered.api.network.ProtocolVersion;
 import com.velocitypowered.api.proxy.messages.ChannelIdentifier;
+import com.velocitypowered.api.proxy.messages.LegacyChannelIdentifier;
+import com.velocitypowered.api.proxy.messages.MinecraftChannelIdentifier;
 import com.velocitypowered.api.proxy.player.ResourcePackInfo;
 import com.velocitypowered.proxy.VelocityServer;
 import com.velocitypowered.proxy.command.CommandGraphInjector;
@@ -288,31 +290,14 @@ public class BackendPlaySessionHandler implements MinecraftSessionHandler {
       return true;
     }
 
-    // Register and unregister packets are simply forwarded to the server as-is.
-    if (PluginMessageUtil.isRegister(packet) || PluginMessageUtil.isUnregister(packet)) {
-      return false;
-    }
-
-    if (PluginMessageUtil.isMcBrand(packet)) {
-      PluginMessagePacket rewritten = PluginMessageUtil
-              .rewriteMinecraftBrand(packet,
-                      server.getVersion(), playerConnection.getProtocolVersion());
-      playerConnection.write(rewritten);
-      return true;
-    }
-
     if (serverConn.getPhase().handle(serverConn, serverConn.getPlayer(), packet)) {
       // Handled.
       return true;
     }
 
-    ChannelIdentifier id = server.getChannelRegistrar().getFromId(packet.getChannel());
-    if (id == null) {
-      return false;
-    }
-
     byte[] copy = ByteBufUtil.getBytes(packet.content());
-    PluginMessageEvent event = new PluginMessageEvent(serverConn, serverConn.getPlayer(), id, copy);
+    String channel = packet.getChannel();
+    PluginMessageEvent event = new PluginMessageEvent(serverConn, serverConn.getPlayer(), channel.indexOf(':') == -1 ? new LegacyChannelIdentifier(channel) : MinecraftChannelIdentifier.from(channel), copy);
     server.getEventManager().fire(event).thenAcceptAsync(pme -> {
       if (pme.getResult().isAllowed() && !playerConnection.isClosed()) {
         PluginMessagePacket copied = new PluginMessagePacket(

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

@@ -340,43 +340,25 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
         }
 
         if (!player.getPhase().handle(player, packet, serverConn)) {
-          ChannelIdentifier id = server.getChannelRegistrar().getFromId(packet.getChannel());
-          if (id == null) {
-            // We don't have any plugins listening on this channel, process the packet now.
-            if (!player.getPhase().consideredComplete() || !serverConn.getPhase()
-                .consideredComplete()) {
-              // The client is trying to send messages too early. This is primarily caused by mods,
-              // but further aggravated by Velocity. To work around these issues, we will queue any
-              // non-FML handshake messages to be sent once the FML handshake has completed or the
-              // JoinGame packet has been received by the proxy, whichever comes first.
-              //
-              // We also need to make sure to retain these packets, so they can be flushed
-              // appropriately.
-              loginPluginMessages.add(packet.retain());
-            } else {
-              // The connection is ready, send the packet now.
-              backendConn.write(packet.retain());
-            }
-          } else {
-            byte[] copy = ByteBufUtil.getBytes(packet.content());
-            PluginMessageEvent event = new PluginMessageEvent(player, serverConn, id, copy);
-            server.getEventManager().fire(event).thenAcceptAsync(pme -> {
-              if (pme.getResult().isAllowed()) {
-                PluginMessagePacket message = new PluginMessagePacket(packet.getChannel(),
-                    Unpooled.wrappedBuffer(copy));
-                if (!player.getPhase().consideredComplete() || !serverConn.getPhase()
-                    .consideredComplete()) {
-                  // We're still processing the connection (see above), enqueue the packet for now.
-                  loginPluginMessages.add(message.retain());
-                } else {
-                  backendConn.write(message);
-                }
+          byte[] copy = ByteBufUtil.getBytes(packet.content());
+          String channel = packet.getChannel();
+          PluginMessageEvent event = new PluginMessageEvent(player, serverConn, channel.indexOf(':') == -1 ? new LegacyChannelIdentifier(channel) : MinecraftChannelIdentifier.from(channel), copy);
+          server.getEventManager().fire(event).thenAcceptAsync(pme -> {
+            if (pme.getResult().isAllowed()) {
+              PluginMessagePacket message = new PluginMessagePacket(packet.getChannel(),
+                      Unpooled.wrappedBuffer(copy));
+              if (!player.getPhase().consideredComplete() || !serverConn.getPhase()
+                      .consideredComplete()) {
+                // We're still processing the connection (see above), enqueue the packet for now.
+                loginPluginMessages.add(message.retain());
+              } else {
+                backendConn.write(message);
               }
-            }, backendConn.eventLoop()).exceptionally((ex) -> {
-              logger.error("Exception while handling plugin message packet for {}", player, ex);
-              return null;
-            });
-          }
+            }
+          }, backendConn.eventLoop()).exceptionally((ex) -> {
+            logger.error("Exception while handling plugin message packet for {}", player, ex);
+            return null;
+          });
         }
       }
     }