gofi provides a super simple API for sending and receiving data-link packets over WiFi.

Right now, gofi is only supported on OS X. This will surely change soon, as I plan to write an implementation for Linux.

NOTE: you can find full documentation on Godoc.

To start transferring data over a WiFi device, you must create a Handle. For example:

handle, err := gofi.NewHandle("en1")

If you do not know the interface name for your WiFi device ahead of time, gofi gives you an easy way to figure it out:

name, err := gofi.DefaultInterfaceName()
if err != nil {
    // The system has no default WiFi defice!!!
    panic("do something here")
}
handle, err := gofi.NewHandle(name)

Since WiFi communications can take place on any number of channels, you will most likely want to hop channels immediately. You can do this using the SetChannel function:

handle.SetChannel(gofi.Channel{Number: 11})

Once you're tuned into a channel, you can receive packets using the Receive function. For example:

for {
	frame, radio, err := handle.Receive()
	if err != nil {
        // Could not read any more data! Maybe the device was unplugged.
		break
	}
	sourceMACAddress := frame[4:10]
	fmt.Println("got", len(frame), "bytes on frequency", radio.Frequency,
        "MHz", "from MAC", sourceMACAddress)
}

Sending packets is simple as well, but crafting the packets is up to you!

frame := gofi.Frame("\x80\x00\x00...")
if err := handle.Send(frame, 0); err != nil {
    // Could not send the packet! Did you remember to compute the trailing checksum?
}