AP mode (via hostapd) support for wifi chips that identify themselves as RTL8188CUS (or variants thereof). If you've seen or heard someone claim that a certain wifi chip works with a special version of hostapd driver called rtl871xdrv, this is it.

This is not the full hostapd source however. These are just patches and extra code to compile rtl871xdrv with a fresh hostapd source.

Wifi chips like RT8188C and RT8192C, recognized as RTL8188CUS (or variants thereof) do not support the standard nl80211 driver of hostapd. Their in-kernel drivers are also buggy and not very featureful. Realtek released their drivers for such chips under the GPL, but never bothered to update them. But I guess a one-time code dump is better than no source code at all.

Realtek's code dump contained a kernel driver and a special driver for hostapd. (What is this? 2005?) As of writing, the kernel driver is being maintained for modern kernels at dz0ny/rt8192cu.

The hostapd driver however, wasn't provided as a driver. A modified hostapd, somewhere in its 0.8.x version, was dumped. If you wanted a newer hostapd, well, too bad.

This repo has the extracted modifications to mainline hostapd done by Realtek, adapted for hostapd 2.5. For other versions of hostapd, checkout to the corresponding tag.

Get a fresh copy of hostapd source from your distro or from http://w1.fi/hostapd/; I suggest the former, but if you have reason to use the latter, go ahead.

Make sure you can build hostapd before proceeding.

Inside the directory that contains hostapd, src, wpa_supplicant, apply the patch:

$ patch -Np1 -i </path/to/rtl871xdrv.patch>

Make sure you enable the driver in .config.

$ echo CONFIG_DRIVER_RTW=y >> .config

Credits: oblique

(If you don't know what .config is, then you haven't build vanilla hostapd yet. You should have been able to do it before applying the patch.)

Now you're all set. Rebuild hostapd and use.

A simple hostapd.conf file has been provided.

At the time of releasing this, the mainline driver worked well enough for STA mode operation. The kernel driver from Realtek was only needed for AP mode.

No code here has been written by me, only existing code from Realtek has been modified. As per the original license:

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License version 2 as
published by the Free Software Foundation.

Alternatively, this software may be distributed under the terms of BSD
license.