Merge pull request #58 from PaperMC/dev/3.0.0

[pull] main from PaperMC:dev/3.0.0

Author: pull[bot]

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

@@ -68,6 +68,7 @@
 import com.velocitypowered.proxy.protocol.packet.UpsertPlayerInfoPacket;
 import com.velocitypowered.proxy.protocol.packet.chat.ComponentHolder;
 import com.velocitypowered.proxy.protocol.packet.config.StartUpdatePacket;
+import com.velocitypowered.proxy.protocol.util.DeferredByteBufHolder;
 import com.velocitypowered.proxy.protocol.util.PluginMessageUtil;
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.ByteBufUtil;
@@ -91,6 +92,7 @@ public class BackendPlaySessionHandler implements MinecraftSessionHandler {
       Boolean.getBoolean("velocity.log-server-backpressure");
   private static final int MAXIMUM_PACKETS_TO_FLUSH =
       Integer.getInteger("velocity.max-packets-per-flush", 8192);
+  private static final int LARGE_PACKET_THRESHOLD = 1024 * 128;
 
   private final VelocityServer server;
   private final VelocityServerConnection serverConn;
@@ -455,17 +457,19 @@ public void handleGeneric(MinecraftPacket packet) {
     if (packet instanceof PluginMessagePacket pluginMessage) {
       pluginMessage.retain();
     }
+    boolean huge = packet instanceof DeferredByteBufHolder def && def.content().readableBytes() > LARGE_PACKET_THRESHOLD;
     playerConnection.delayedWrite(packet);
-    if (++packetsFlushed >= MAXIMUM_PACKETS_TO_FLUSH) {
+    if (huge || ++packetsFlushed >= MAXIMUM_PACKETS_TO_FLUSH) {
       playerConnection.flush();
       packetsFlushed = 0;
     }
   }
 
   @Override
   public void handleUnknown(ByteBuf buf) {
+    boolean huge = buf.readableBytes() > LARGE_PACKET_THRESHOLD;
     playerConnection.delayedWrite(buf.retain());
-    if (++packetsFlushed >= MAXIMUM_PACKETS_TO_FLUSH) {
+    if (huge || ++packetsFlushed >= MAXIMUM_PACKETS_TO_FLUSH) {
       playerConnection.flush();
       packetsFlushed = 0;
     }

proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/PluginMessagePacket.java

@@ -31,7 +31,8 @@
 
 public class PluginMessagePacket extends DeferredByteBufHolder implements MinecraftPacket {
 
-  private static final int MAX_PAYLOAD_SIZE = Integer.getInteger("velocity.max-plugin-message-payload-size", 32767);
+  private static final int MAX_PAYLOAD_SIZE_CLIENTBOUND = getPayloadLimit(Direction.CLIENTBOUND);
+  private static final int MAX_PAYLOAD_SIZE_SERVERBOUND = getPayloadLimit(Direction.SERVERBOUND);
 
   private @Nullable String channel;
 
@@ -52,6 +53,19 @@ public String getChannel() {
     return channel;
   }
 
+  private static int getPayloadLimit(Direction direction) {
+    if (System.getProperty("velocity.max-plugin-message-payload-size") != null) {
+      return Integer.getInteger("velocity.max-plugin-message-payload-size");
+    }
+    if (direction == Direction.SERVERBOUND) {
+      return Integer.getInteger("velocity.max-plugin-message-payload-size.serverbound", 32767);
+    } else {
+      // This is the vanilla expected limit, a payload this large feels like a nightmare given the trust
+      // we give to servers...
+      return Integer.getInteger("velocity.max-plugin-message-payload-size.clientbound", 1048576);
+    }
+  }
+
   public void setChannel(String channel) {
     this.channel = channel;
   }
@@ -104,7 +118,8 @@ public void encode(ByteBuf buf, ProtocolUtils.Direction direction, ProtocolVersi
 
   @Override
   public int decodeExpectedMaxLength(ByteBuf buf, Direction direction, ProtocolVersion version) {
-    return ProtocolUtils.DEFAULT_MAX_STRING_BYTES + MAX_PAYLOAD_SIZE;
+    return ProtocolUtils.DEFAULT_MAX_STRING_BYTES +
+        (direction == Direction.CLIENTBOUND ? MAX_PAYLOAD_SIZE_CLIENTBOUND : MAX_PAYLOAD_SIZE_SERVERBOUND);
   }
 
   @Override