PangYa Packet Reference

Welcome to Packetdoc, an unofficial document and Kaitai Struct definition describing the structure of the PangYa protocol and individual PangYa packets.

PangYa is an MMORPG golf game released by Ntreev Soft in 2004.

The PangYa protocol is a simple TCP-based protocol for encrypting and transmitting PangYa packets. To understand the full picture behind PangYa's network communications, you should start by reading the protocol page, which describes the encryption and framing of individual PangYa packets. The remainder of this document will focus on documenting the structure of the decrypted packets themselves, such as the payloads you would encrypt and decrypt using PangCrypt. Henceforth, the decrypted payloads that this documentation mostly focuses on will be referred to as "PangYa packets."

The PangYa server stack is divided into 3 different network services:

• LoginService: Provides basic authentication capabilities.
• GameService: Synchronizes game state across clients.
• MessageService: Provides messaging capabilities.

From here, the client and server have their own distinct types of packets for each service.

How To Use

If you wish to implement a PangYa server or client, take a look at PangCrypt. It implements most of the bits you will need for the framing part of the protocol. You will still need to manually read and calculate the length so you can segment the TCP stream correctly.

Once you have an implementation of the framing protocol, you can then use this reference in one of two ways:

• The KaitaiStruct definition that generates the packet pages can actually be used to generate code for decoding packets in multiple programming languages. (Ability to encode packets is not available in stable KaitaiStruct.)

• The documentation and KaitaiStruct definitions should provide enough information to construct and parse packets (usually.)

Understanding the packet flows will probably still require some analysis of packet dumps.

If you wish to dissect a packet, you have multiple options.

• PangCrypt and its unpangle tool can be used to get the payload from TCP packets.

• The KaitaiStruct definition that generates the packet documentation can be used to decode packets. You could generate code and use it in the programming language of your choice.

• You could use a KaitaiStruct tool like KaitaiStruct Visualizer.

WARNING: KaitaiStruct WebIDE does not work well with Packetdoc definitions for two reasons:

• WebIDE decodes packets based on the currently open file, and does not support passing parameters yet, so you must open the index.ksy file in the folder of the type of packet you're dealing with; while the individual packet struct is open, decoding will fail because the packet ID present in your payload will cause decoding to fail, as individual packet structs do not contain a packet ID entry.

• WebIDE does not support imports on files in the user filesystem.

TODO: Describe how to do these things. Ideally, provide the tools directly.

TODO: Work to implement serialization in KaitaiStruct compiler so that the KaitaiStructs can be used for encoding packets too.

Terminology

Client vs Server

The term 'client' and 'server' here refer to the PangYa game and PangYa servers, respectively. Client packets are packets created by the client and consumed by the server. Server packets are packets created by the server and consumed by the server. When referring to encryption and decryption, following PangCrypt's nomenclature instead of the older pang.dll nomenclature, encryption and decryption are labeled according to which packets they operate on, so Client Decrypt would decrypt packets created by the client and Server Encrypt would encrypt packets created by the server.

Packets vs Frames

When we say packets, we do not refer to the individual frames of the PangYa protocol that make up the TCP streams, but rather we refer to the payloads that they contain. Although this terminology may be confusing, it is consistent with existing usages in the community. When referring to the structure containing the packet, we call it the frame. PangYa packet can be thought of as being the level of abstraction at which PangYa game logic is encapsulated, whereas lower levels deal with framing, encryption and compression.