FreeBSD net80211 template driver

Introduction

This is a templated implementation of FreeBSD's 15-CURRENT net80211 layer. This driver is intended as a learning resource.

This driver is as much a project for myself as it is for any future readers :)

The driver does not implement PCIe, USB or SDIO layers. Rather, everything is implemented in software.

On a FreeBSD host, run the following:

git clone https://github.com/khanzf/i3e_template_driver
cd i3e_template_driver
make
make load

This should create a i3e0 interface. You can now use this to create a VAP.

To create a wlan0 VAP, run the following command:

ifconfig wlan create wlandev i3e0

Like all drivers, this might come off like a wall of code with no context. The order to read this code is:

i3e_attach - Executed after the device is identified by the probe function. Note, because this driver is a software-only implementation, not a real USB, PCI or SDIO driver. It should power on the device, read any hardcoded values (ie, device version, MAC address, etc) and enable the device accordingly. The end result will be the i3e0 interface.
- Subfunction i3e_getradiocaps - Sets the device modes and frequencies. Technically this could be merged or inlined into i3e_attach, but keeping it a separate function is convention.
i3e_parent, i3e_vap_create and i3e_init - These three functions operate in tandem when creating the interface with ifconfig wlan create wlandev i3e.
- i3e_vap_create - This is executed when wlan, which is a virtual interface to connect to multiple nodes at once.
- i3e_parent - This function is executed when the device is set to up or down. It must be assigned in i3e_attach, such as ic->ic_parent = i3e_parent. If the device is off, it will run i3e_init and then start or stop all VAPs.
- i3e_init - This function turns the device on and starts reading or writing.

This code is licensed under the 2-Clause BSD.

The author of this is code Farhan Khan (farhan@farhan.codes)