Setting up hostapd on the utilite

Synopsis

This article describes how-to enable the utilte as a WiFi Access Point.

Before you start

Install ubuntu 14.04.1

Get and install the ubuntu 14.04.1 install image mentioned here. This archive comes with the linux 3.10.17 kernel image (default kernel) and the necessary kernel modules needed to run hostapd (8). Newer mainline kernels (3.15, 3.16, etc. ) still lack the support for the build-in Marvell SDIO WiFi interface (mwifiex). If you take another kernel image, please make sure that the kernel is compiled with CONFIG_BRIDGE=y.

Verify that your WiFi device is AP-mode capable

You may verify the device's ability to run in AP-mode with sudo iw list and look for the section starting with

...
Supported interface modes:
    ...
    * AP
...

Set-up the Access Point

Install and configure hostapd

This package isn't included in the install image, you need to install it separately:

sudo apt-get install hostapd
sudo echo 'DAEMON_CONF="/etc/hostapd/hostapd.conf"' >/etc/default/hostapd

The hostapd configuration file is quite self explanatory, here you find the differences between the shipped version and my recent configuration:

root@armh0:/etc/hostapd# rcsdiff -r1.1 hostapd.conf
===================================================================
RCS file: hostapd.conf,v
retrieving revision 1.1
diff -r1.1 hostapd.conf
6c6
< interface=wlan0
---
> interface=uap0
19c19
< #bridge=br0
---
> bridge=br0
25c25
< # driver=hostap
---
> driver=nl80211
629c629
< #ieee8021x=1
---
> ieee8021x=0
991c991
< #wpa=1
---
> wpa=2
1000c1000
< #wpa_passphrase=secret passphrase
---
> wpa_passphrase=0123456789
1021c1021
< #wpa_key_mgmt=WPA-PSK WPA-EAP
---
> wpa_key_mgmt=WPA-PSK WPA-PSK-SHA256

Set-up bridging

If you want to let the utilite operate as a WiFi Access Point you need to bridge the WiFi device and the ethernet device (the necessary package (bridge-utils) is already installed). Here you find the network configuration (/etc/network/interfaces) doing this on the utilite:

auto lo br0

iface lo inet loopback

iface br0 inet static
  pre-up iw phy phy0 interface add uap0 type __ap
  address 10.0.0.251
  netmask 255.255.255.0
  network 10.0.0.0
  broadcast 10.0.0.255
  gateway 10.0.0.253
  dns-nameservers 10.0.0.253
  bridge-ports eth0 mlan0

The pre-up command creates the AP management interface (uap0) for mlan0 and circumvents the following error:

ieee80211 phy0: mlan0: changing to 3 not supported

(for further details see here). If you add other WiFi USB devices, the numbering for the phy0, phy1, ... device may change.

Have fun

service hostapd restart