Wifi repeater/hotspot with a single wireless network interface in Debian

Question

I am attempting to create a wireless hotspot/repeater in Debian using create_ap, yet when I run:

create_ap wlan0 wlan0 AP_Name Passphrase

I get met with the following error message:

ERROR: Your adapter can not be a station (i.e. be connected) and an AP at the 
same time

My wireless card is a BCM4312.

---

I would be happy to accept that it's a limitation of my adapter, however, I am easily able to use the Windows 10 "Mobile Hotspot" feature to create a hotspot while still connected to wifi (no additional wireless card/ethernet connection required).

So why is it that windows is able to use my wireless card as a station and an AP at the same time, but create_ap isn't? Is it just limitation in the software, and if so, is there any known software that will allow me to connect to wifi and be an AP at the same time?

I would appreciate any suggestions or ideas, and can provide additional information if needed!

Edit:

The output of lspci -knn | grep Net -A2 is:

08:00.0 Network controller [0280]: Broadcom Limited BCM4312 802.11b/g LP-PHY [14e4:4315] (rev 01)
    Subsystem: Dell Wireless 1397 WLAN Mini-Card [1028:000c]
    Kernel driver in use: b43-pci-bridge

Answer 1

From the output of lspci , you should use the proprietary driver wl instead of the open source b43.

Install the broadcom-sta-dkms following the instruction described on the official documentation.

Add a "non-free" component to /etc/apt/sources.list for your Debian version, for example:

# Debian 9 "Stretch"
deb http://httpredir.debian.org/debian/ stretch main contrib non-free

Update the list of available packages. Install the relevant/latest linux-image, linux-headers and broadcom-sta-dkms packages:

# apt-get update
# apt-get install linux-image-$(uname -r|sed 's,[^-]*-[^-]*-,,') linux-headers-$(uname -r|sed 's,[^-]*-[^-]*-,,') broadcom-sta-dkms

This will also install the recommended wireless-tools package. DKMS will build the wl module for your system.

Unload conflicting modules:

# modprobe -r b44 b43 b43legacy ssb brcmsmac bcma b43-pci-bridge

Load the wl module:

# modprobe wl

Create you AP, Internet sharing from the same WiFi interface:

create_ap wlan0 wlan0 MyAccessPoint MyPassPhrase