Alkahest

Alkahest is a proxy server for TERA. At its core, it is simply a server that relays communication between the game client and server. Its main usefulness lies in its extensibility; you can write plugins that can inspect packets, modify them, and send newly constructed packets. This opens up a lot of possibilities for integrating the game with other software, as well as adding entirely new features to the game, so long as you can do so within the framework of the game's network protocol.

This project was started out of a need to have a program similar to tera-proxy, but written in a .NET language so that it could easily use the Windows Presentation Foundation libraries for the purpose of making a UI overlay for the game. It has since grown to be a more general-purpose framework for TERA modding, featuring tools and APIs for accessing data stored with the game client.

Features

.NET plugins: Plugins can be written in any .NET language, including C#, F#, Nemerle, etc.
C# scripting: A default plugin enables scripting with C#, via Roslyn.
Packet manipulation: Packets can easily be intercepted, modified, or even constructed from scratch, in either raw or typed form.
Fast packet serialization: Specialized serialization functions are automatically generated and compiled at runtime, making packet serialization fast and painless.
Extensive region support: Almost all TERA regions are supported: DE, FR, JP, NA, RU, SE, TH, TW, and UK.
Proxy interoperability: Alkahest supports seamless interoperability with TERA Toolbox, Shinra Meter, and other similar projects.
Reusable core library: The Alkahest server is merely a wrapper around the Alkahest.Core library which can be embedded in any .NET application.
Client analysis tools: Data mining tools allow extraction of game messages, system messages, and data center keys, as well as decryption of the client's data center files.
Packet logging: Compressed packet logs can be saved for later parsing and analysis.
Packet parser: An offline packet parsing tool can generate text dumps of packet logs and analyze raw packet structures to find arrays and strings.

Installation

Archives with compiled binaries are available from the releases page.

Alkahest requires .NET Framework 4.7.2 to run.

If you want to build Alkahest from source, you will need Visual Studio 2019 (any edition). The code base is written in C# 8.0, so earlier versions will not work.

After cloning the repository, make sure to run:

git submodule update --init --recursive

(Or alternatively, clone with the --recursive option.)

Next, simply open Alkahest.sln and build it with the Debug + Any CPU configuration. All build artifacts will end up in the Build directory.

If you want to build the NuGet package, run this command after building:

msbuild /t:Pack Alkahest.Core

This will create a file named something like Alkahest.Core.1.0.0.nupkg in the Build directory.

Configuration

After you have installed Alkahest, you will need to configure it. This is done in the Alkahest.exe.config file. You can find that file in the Build directory if you have built Alkahest from source, or in the directory you installed Alkahest to.

The most important configuration values you will need to change are:

logLevel: Most users should set this to basic. You can set it higher if you do not mind some extra output. Developers should probably leave this at debug.
loggers: If you do not care much about keeping logs around, remove the file logger from this list to save disk space.
disablePlugins: Most users can add packet-logger to this list to save disk space, as they likely will not need packet logs.
regions: Set this to any of de, fr, jp, na, ru, se, th, tw, and uk, depending on which region(s) you intend to play in.

There are many other configuration values that you can play with, but you do not need to change them if all you want is to use Alkahest for a single TERA client on your local machine.

Usage

Once you have configured Alkahest, run Alkahest.exe to start it. Once Alkahest finishes initializing, and if everything went fine, you should be able to just start TERA and play.

For some regions, you may need to log into TERA first, then start Alkahest just before actually launching the game. This is necessary because some regions use the same host name for logging in and for retrieving the server list, the latter of which gets redirected by Alkahest.

Note that, by default, Alkahest will adjust your hosts file so that the host name that the TERA launcher fetches the official server list from will be redirected to wherever Alkahest is configured to be listening. This is necessary so that Alkahest can give the client a modified server list where all IP addresses point to where Alkahest is listening for each server. Alkahest will also install root certificates if the region you are playing on requires HTTPS for the server list. Both of these actions require administrative privileges, so you must run Alkahest as administrator.

If Alkahest terminates abnormally, you can run Alkahest.exe serve -c on the command line to clean up the aforementioned system changes.

When a new version of Alkahest is released, you can run Alkahest.exe upgrade to upgrade en existing installation.

Extensibility

Alkahest can be exteneded with plugins and script packages. Script packages are the preferred way to add functionality to Alkahest as they can be distributed via the package registry. See this page for information about versioning and API/ABI stability.

Plugins can be installed simply by dropping the compiled assembly into the Plugins directory. Alkahest will load and start/stop it automatically. A list of all known plugins can be found here.

Script packages can be managed with Alkahest's package management commands:

info: Show detailed information for given packages.
install: Install given package(s).
purge: Uninstall all packages.
search: Search for packages by regex.
uninstall: Uninstall given package(s).
update: Update given package(s) or all packages.

For example, Alkahest.exe install example installs the example package, Alkahest.exe update updates all installed packages, Alkahest.exe search foo finds all packages containing the string foo in either name or description, etc.

Disclaimer

Technically, using Alkahest could be considered a violation of the terms of service for all TERA regions. Historically, most publishers have chosen to tolerate programs such as Shinra Meter, tera-proxy, Alkahest, etc as long as they are not used for malicious purposes. You will almost certainly be fine as long as you do not do anything really stupid. That said, I take absolutely no responsibility if you do manage to get yourself banned.

Also, Alkahest is meant to enable players to write useful plugins that can enhance the TERA experience. It is not meant to enable cheating of any sort. It may or may not be the case that some aspects of TERA's network protocol can be exploited due to poor design (mainly trusting the client too much). Either way, I do not condone using Alkahest for this, and I certainly will not support such usage. I would encourage people to report such exploits to the TERA developers (usually through whichever publisher your server is at).

Acknowledgements

Please see ACKNOWLEDGEMENTS.md.

Contributing

Please see CONTRIBUTING.md.

License

Please see LICENSE.md.

Funding

I work on open source software projects such as this one in my spare time, and make them available free of charge under permissive licenses. If you like my work and would like to support me, you might consider sponsoring me. Please only donate if you want to and have the means to do so; I want to be very clear that all open source software I write will always be available for free and you should not feel obligated to donate or pay for it in any way.

tera-alkahest / alkahest