A Diablo II (Legacy) Library

A Diablo II library for core and simple client functionality, written in Rust for performance, safety and re-usability.

This effort is very much WIP, so it is not available on crates.io yet.

If you are interested in Diablo II and/or Rust, this might be fun!

Goals

• cross platform without runtime/VM requirement
• provide game internal data structures and methods
• savegame load/save support (for e.g. character editors, armory-style webpages)
• implement the network protocol as fully supported as possible (i.e. however much is known publically)
• reproduce game state as accurately as possible/needed

Milestones

1. network protocol support
   • D2GS (plain)
   • D2GS (compressed)
   • BNCS (It if is used in D2R at all)
   • MCP Realm Logon
2. Game State Data Structures.
   • Items and Buffers (Ground, Inventory, Stash, Cube, Belt)
   • Players (WIP)
   • Players Quest Progression
   • NPCs (WIP)
   • Party/Hostile
   • Game Quest Progression
   • Maps (generate from game seed, take from d2bs)
   • Pathing(?)
3. Client object
   • shadow client (packet listener w/ game update loop WIP)
   • active client / protocol state machine

How to Build

Building on windows requires some extra steps, otherwise it should be smooth sailing.
At this early stage I haven't created any bindings, but Python/TypeScript would be useful to many people, I guess.

Linux

Tested with Diablo 2 (Legacy) and WINE cargo build --release

Mac Os

cargo build --release (not tested yet)

Windows

You will need to install ncap or the WinPcap Developers Pack as per the libpnet build instructions for Windows (I tested the latter). Then point your user environment variable LIB (create if nonexistent) to the folder where to find Packet.lib i.e. WpdPack/Lib/x64/ from the WinPcap Developers Pack you just downloaded. Then cargo build --release This will get the project building.
Currently, in order to find the internet-connected network interface, it is necessary to disable disconnected-but-enabled interfaces (such as virtual adaperts for VPN).

Usage

One simple use case that is supported now is launching a shadow client to sniff d2gs packets.
Put the following code in your main.rs and run it. Then start up your D2 or D2R game client, join a game and watch the game packets flow.

use libd2r::Client;

fn main() {
    let mut client = Client::new();
    client.start()
}

Please note that currently it does not fill any internal game data structures (state update handling is still WIP). It will just filter, decode and print packets. Also, make sure to not have multiple game clients running as currently their packages will be indistinguishable in the output.

Contributing

This is quite the challenge so any help is appreciated!
There is quite a bit of awesome code out there, but scattered across various sources.
Maybe you want to help translating this d2r savegame utility from go (for D2R save files)?
Or help with the map generation from game seed? It exists in several projects (d2bs, opendiablo, opend2, ...) and shouldn't have changed for D2R.

Disclaimer

Little of this works yet and most probably never will. Unless you feel like contributing, which is welcome, it is mostly an exercise.
Here are some great resources on the original game:

• client-less C# bot by dkuwahara
• a blog post by Eric Carmichael
• and, of course, D2BS
• Another good resource is the diablo 2 protocol js library.