georgezero/rpi-hostap repository overview

⁠Docker container stack: hostap + dhcp server

Designed to work on Raspberry Pi (arm) using as base image alpine linux (very little size).

⁠Idea

Since my last change on ISP, they put a cable modem with a horrible Wireless, it drops lots of packets, and I didn't want to put an extra AP or wireless router.

Most of the time use wireless devices on same room so I decided to try to convert my current Pi on a small Access Point using a small USB dongle.

Made minor changes to support for older USB dongles that only support G and now can pass IEEE80211N=0. Also example below shows passing HT_CAPAB values for older USB wifi standards.

⁠Requirements

On the host system, the ralink firmware (in my case) should be installed so you can use it on AP mode. On debian/raspbian:

apt-get install firmware-ralink

Make sure your USB support AP mode:

# iw list
...
        Supported interface modes:
                 * IBSS
                 * managed
                 * AP
                 * AP/VLAN
                 * WDS
                 * monitor
                 * mesh point
...

Set country regulations, for excample, to Spain set:

# iw reg set ES
country ES: DFS-ETSI
        (2400 - 2483 @ 40), (N/A, 20), (N/A)
        (5150 - 5250 @ 80), (N/A, 23), (N/A), NO-OUTDOOR
        (5250 - 5350 @ 80), (N/A, 20), (0 ms), NO-OUTDOOR, DFS
        (5470 - 5725 @ 160), (N/A, 26), (0 ms), DFS
        (57000 - 66000 @ 2160), (N/A, 40), (N/A)

⁠Build / run

For modification, testings, etc.. there is already a Makefile. So you can make run to start a sample ssid with a simple password.

I've already uploaded the image to docker hubs, so you can run it from ther like this:

sudo docker run -d -t \
  -e INTERFACE=wlan0 \
  -e CHANNEL=6 \
  -e SSID=runssid \
  -e APADDR=192.168.254.1 \
  -e SUBNET=192.168.254.0 \
  -e WPA_PASSPHRASE=passw0rd \
  -e IEEE80211N=0 \
  -e HT_CAPAB=[HT20][SHORT-GI-20] \
  -e OUTGOINGS=eth0 \
  --privileged \
  --net host \
  georgezero/rpi-hostap:latest

To test interactively, you may want to start a tmux session and then:

sudo docker run -it \
  -e INTERFACE=wlan0 \
  -e CHANNEL=6 \
  -e SSID=runssid \
  -e APADDR=192.168.254.1 \
  -e SUBNET=192.168.254.0 \
  -e WPA_PASSPHRASE=passw0rd \
  -e IEEE80211N=0 \
  -e HT_CAPAB=[HT20][SHORT-GI-20] \
  -e OUTGOINGS=eth0 \
  --privileged \
  --net host \
  georgezero/rpi-hostap:latest

But before this, hostap usually requires that wlan0 interface to be already up, so before docker run take the interface up:

/sbin/ifconfig wlan0 192.168.254.1/24 up

Also you should have a driver to enable hostap on your USB wifi

apt-get install firmware-ralink

Credit: Modified from https://github.com/sdelrio/rpi-hostap⁠