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Libwifi

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First of all, this library is designed to be easily extendable.
There's an architectural/contribution guide in docs/Frame.md and pull requests are highly welcome.

Covering the whole spectrum of possible 802.11 frames or all different implementations of wifi tools out there is an impossible task for a single person, let's try to tackle this together!

What is Libwifi

The first goal of libwifi is to provide a convenient way of parsing raw IEEE 802.11 frames!

The emphasis is on convenient, since this library doesn't focus on providing an ultra-high-performance implementation. The focus is rather on providing an easy-to-use API.
This includes consistent and intuitive structs that represent the structure of a given frame.
However, this doesn't mean that this library isn't quite fast anyway ;).

The second goal is to provide a unified API to:

  1. query information about your wifi interfaces (iwlist equivalent).
  2. set attributes and configure your wifi interfaces (iwconfig equivalent).

As a prototype implementation, it's planned to call existing binaries and parse their output. However, a native re-implementation of those tools is most definitely desirable in the long term.
For instance, the wireless-tools are a great C project with a lot of documentation and very well structured code. This could be used as a guideline when working on a re-implementation.

The project is still under heavy development, and a lot of features are missing, but it should be a good foundation for a proper wifi library :).

How to use it

Parsing a frame is fairly straight forward:

use libwifi::parse_frame;

// A simple RTS frame
let bytes = [
    180, 0, // FrameControl
    158, 0, // Duration
    116, 66, 127, 77, 29, 45, // First Address
    20, 125, 218, 170, 84, 81, // Second Address
];

match libwifi::parse_frame(&bytes) {
    Ok(frame) => {
        println!("Got frame: {frame:?}");
    }
    Err(err) => {
        println!("Error during parsing :\n{err:?}");
    }
};

A full example on how to capture, process and parse wifi traffic can be found in the examples directory.

Performance

There are a few benchmarks in the benches folder, which can be run by calling cargo bench.

Right now, parsing a Beacon frame, which is one of the more complex frames, takes ~1 µs on a i7-8550U.
Parsing a Data frame takes ~84 ns.

If we take this as a rough guideline, you can roughly expect a million frames per second per core on that CPU.

Disclaimer: This will most likely become slower, as more missing features/parsers will be added to the library. Anyhow, I don't expect this to drop below 100k frames/s.

Roadmap and TODOs

Parser and Frames

  • Implement basic parsers for all frame subtypes.
  • Add specialized parsers for fields that are currently generically handled by the StationInfo struct.
  • Handle all edge-cases (there are a lot and I'll need help!)

Interface handling

I would love to add proper interface handling to the library. This includes features to:

  • Switch modes
  • Switch channels
  • Discover available channels

Implementation status

  • Management Frames
    • AssociationRequest,
    • AssociationResponse,
    • ReassociationRequest,
    • ReassociationResponse,
    • ProbeRequest,
    • ProbeResponse,
    • TimingAdvertisement,
    • Beacon,
    • Atim,
    • Disassociation,
    • Authentication,
    • Deauthentication,
    • Action,
    • ActionNoAck,
  • Control Frames
    • Trigger,
    • Tack,
    • BeamformingReportPoll,
    • NdpAnnouncement,
    • ControlFrameExtension,
    • ControlWrapper,
    • BlockAckRequest,
    • BlockAck,
    • PsPoll,
    • Rts,
    • Cts,
    • Ack,
    • CfEnd,
    • CfEndCfAck,
  • Data Frames
    • Data,
    • DataCfAck,
    • DataCfPoll,
    • DataCfAckCfPoll,
    • NullData,
    • CfAck,
    • CfPoll,
    • CfAckCfPoll,
    • QosData,
    • QosDataCfAck,
    • QosDataCfPoll,
    • QosDataCfAckCfPoll,
    • QosNull,
    • QosCfPoll,
    • QosCfAckCfPoll,
  • Frame Components
    • Frame Control
    • Sequence Control
    • Management Header
    • Dynamic Management Header fields
      • SSID
      • Supported rates
      • Generic extraction of remaining fields
      • All other fields
    • Data Header
    • QoS Data Header
      • The QoS flags must still be properly parsed

There's a lot more to the IEE 802.11 spec and a lot of stuff needs to be done.
If you find that something you need is missing, consider creating a ticket and contributing :).