Bering-uClibc 4.x - User Guide - Advanced Topics - Setting Up a Wireless Access Point

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Setting up a wireless access point with WPA


We assume here that you want to create a wireless access point secured by WPA/WPA2. Instructions for using WEP will not be given.

For now, this only includes instructions for pci-cards supported by the hostap and kernel drivers (I use an Atheros WLAN NIC, supported by the ath5k driver). Feedback is welcome about what it takes to make other cards (other chipsets as well as PC-Card and USB models) to work.

Declare the packages

To build a wireless access point one needs the hostapd package hostapd.lrp and its dependencies libssl.lrp, libcrpto.lrp, libnl and libm.lrp.

The packages have to reside on your storage media and added to leaf.cfg.

FIX THIS# Check the Bering-uClibc Installation Guide to learn how to do that.

Declare the required modules

In order to build a wireless access point, you will first have to get the hardware to work, which means adding the proper modules and loading them in the right order, and then adding the configuration for hostapd.

Setup for cards supported by the ath5k driver

Adding the required modules

For setting up an AP with a pci card supported by the ath5k driver, you will need the following modules from the modules tarball available from the the bering-uclibc download area or:

Copy those files to /lib/modules/ on your Bering-uClibc installation and add the following to your /etc/modules file:

At this point, it's probably a good idea to save both the configuration and the modules (from the lrcfg menu). And reboot your router. During the reboot (or afterwards, looking at the output of dmesg) you should see something like:
cfg80211: Calling CRDA to update world regulatory domain
ath5k 0000:00:0c.0: registered as 'phy0'
ath: EEPROM regdomain: 0x0
ath: EEPROM indicates default country code should be used
ath: doing EEPROM country->regdmn map search
ath: country maps to regdmn code: 0x3a
ath: Country alpha2 being used: US
ath: Regpair used: 0x3a
phy0: Selected rate control algorithm 'minstrel'
ath5k phy0: Atheros AR2413 chip found (MAC: 0x78, PHY: 0x45)
cfg80211: Calling CRDA for country: US


Declaring the interface in /etc/network/interfaces Setup in /etc/network/interfaces is minimal, since all of the wlan specific settings will be done in the hostapd configuration. You will only need to declare the proper interface and IP address (since these instructions are for creating an access point, a static IP is assumed). Add the following to /etc/network/interfaces

   auto wlan0
    iface wlan0 inet static 
    wireless-channel 6

Replace the IP address and netmask with whatever you prefer, if you want to use a different net.

Configuring hostapd

First of all, open /etc/default/hostapd and uncomment the line
# RUN_DAEMON='yes'
If you forget to do that, hostapd will not start. Next, open /etc/hostapd/hostapd.conf and enter the following information:
channel 6 #(should be the same as in /etc/network/interfaces)
wpa_pairwise=TKIP CCMP

The comments in that config file are actually very helpful, so you'll want to change the individual settings, rather than replacing the file with the content above. See this site for a nice tool to generate strong preshared keys. Use the string from the first box labeled "64 random hexadecimal characters (0-9 and A-F):" for wpa_psk

Configuring shorewall

wlan wlan0 detect dhcp
to /etc/shorewall/interfaces
wlan ipv4
to /etc/shorewall/zones
update /etc/shorewall/policy and/or /etc/shorewall/rules and/or /etc/shorewall/masq to allow traffic to/from wireless network

Configuring dnsmasq

to /etc/dnsmasq.conf (unless you have dnsmasq listening on all devices anyway). Add an address range to serve by DHCP to /etc/dnsmasq.conf, something like

Finishing up

Save the configuration and reboot - you should now have a working access point

Handling of preshared keys

The WPA key you generated above and put into /etc/hostapd/hostapd.conf needs to be entered on each client that connects to the AP - so you might want to put it onto a USB stick or something like that. But since that key is the only thing that is keeping others from logging onto your net, you should still keep it in a safe place