WiiLink WFC

WiiLink WFC is a revival service for the late Nintendo Wi-Fi Connection (shortened as Nintendo WFC) created and operated by WiiLink. It provides online services for many online Nintendo DS and Wii games that used the original service, primarily targeting games which used the GameSpy backend for online matchmaking, such as Mario Kart Wii. The service is public but officially still in testing, but is nearing the end of the testing period according to its lead developer, Palapeli.

History

Background

Shortly before the original Nintendo WFC service shut down in May 2014, two well-known members from the Mario Kart Wii modding community, Wiimm and Leseratte, worked to maintain the game's online using a custom service they created called Wiimmfi. While the closed-source service was originally intended specifically to keep Mario Kart Wii online, the following years saw it expand support for other WFC-enabled games. Over time the service ended up dominating the revival scene for online Wii games, maintaining a much higher player count than any other alternative service.

Beginning in the early 2020s, some members of the Mario Kart Wii community voiced certain issues with the way Wiimmfi was operated, primarily focused on conflicts with its client-side patches and other game mods. Upon connecting to Wiimmfi using Mario Kart Wii, the service would send a "payload" to your client, which would make various undocumented patches, including critical security patches required to prevent RCE (remote code execution) attacks from other players online. Criticism of the payload centered around its lack of transparency to developers and users about what it did and what changes it made, due to being closed-source, and constant updates to the payload were made without warning. Developers described it as a "binary blob relying on a poorly implemented model of security through obscurity." Additionally, complaints were made about unfair treatment to mod developers regarding access to the payload’s source code, as some prominent developers, specifically the developers of the mod CTGP Revolution, were given access to the source code of the patches and the ability to freely implement it within their own codebase, without having to deal with payload system that other developers were usually subject to.

In 2022, Leseratte, one of the Wiimmfi developers, began releasing more regular updates and information about the payload in response to the criticism from mod developers. He however remained adamant about keeping the payload closed-source, citing concerns about people potentially finding bugs in the code and exploiting them for malicious purposes. This point was quickly disputed by other developers, who pointed out how anyone clever enough to develop exploits would be more than capable of reverse-engineering the payload’s binary to find bugs without the source code, as is common with proprietary software. Leseratte also claimed that the server-side code couldn’t be open-sourced due to licensing restrictions, as Wiimm reused code he wrote for his employer with permission to use but not distribute.

Since then, Wiimm and Leseratte consistently refused help from outside developers, even as the service became increasingly unstable and experienced frequent downtime.

Development

WiiLink WFC began development in September 2023 after the problems with Wiimmfi were repeatedly brought up among the WiiLink team. The project's foundation was spun up by Sketch, but the project ended up being taken over by Palapeli, a Mario Kart Wii mod developer with lots of vested interest in an open-source alternative to Wiimmfi, who ended up becoming the de facto lead developer of WiiLink WFC.

After opening the repository to the public, WiiLink began recruiting players for testing by creating a channel category in WiiLink Discord server. Several other people outside of the WiiLink team began contributing to the project's development through GitHub, most notably a Mario Kart Wii modder named Star, who contributed a significant amount of security and verification to the WiiLink WFC payload, which is downloaded and performs patches on login to WiiLink WFC, much like its Wiimmfi counterpart. Another developer, umbreonisreal on GitHub, also contributed by adding initial support for Nintendo DS games with the nds-constraint exploit.