Feb 082013

As a continuation this post, I have completed the first version of the RaspAP WebGUI. I have yet to decide on a good name for it though.
Continue reading »

Feb 062013

After some experimentation with the RaspAP, I decided to write up a simple web interface for it so that when hostapd started broadcasting, I could use a simple web page rather than ssh to control the wifi and hostapd on the Raspberry Pi. The distribution I used was Raspbian Server Edition once again.

I started off by installing lighttpd and php5

apt-get install lighttpd php5-cgi

After that, I enabled php for lighttpd and restarted it for the settings to take effect.

sudo lighty-enable-mod fastcgi-php
/etc/init.d/lighttpd restart

Now, comes the fun part.
For security reasons, the www-data user which lighttpd runs under is not allowed to start or stop daemons, or run commands like ifdown and ifup, all of which I wanted my page to do.
So what I have done, is added the www-data user to the sudoers file, but with restrictions on what commands the user can run.
The line appears in /etc/sudoers like this –

www-data ALL=(ALL) NOPASSWD:/sbin/ifdown wlan0,/sbin/ifup wlan0,/bin/cat /etc/wpa_supplicant/wpa_supplicant.conf,/bin/cp /tmp/wifidata /etc/wpa_supplicant/wpa_supplicant.conf,/sbin/wpa_cli scan_results,/sbin/wpa_cli scan,/bin/cp /tmp/hostapddata /etc/hostapd/hostapd.conf,/etc/init.d/hostapd start,/etc/init.d/hostapd stop,/etc/init.d/dnsmasq start,/etc/init.d/dnsmasq stop,/bin/cp /tmp/dhcpddata /etc/dnsmasq.conf

Notice I’ve restricted the www-data user to only be able to run the exact commands in the sudoers file
This means that the www-data can only take down, bring up, and show the configuration of wlan0 for example.

After the sudoers file has been modified, the script can now do what it needs to do.
I have a very very rough version written up so far, but it’s not available to download yet.

Here are some screenshots of what it’ll be able to do though ! πŸ™‚

WiFi Information screen

WiFI Client connection screen

WiFi Hotspot setup screen

I’m in the process of prettying up the GUI but in the meantime, this is functional enough πŸ™‚
I’ll get the demo up and running soon enough too ! πŸ™‚

I have released the PHP files for this – Please check this post for details.

Jan 222013

Hey Everyone

I’ve had issues with my WiFi in the past, and with my Pi running headless it’s sometimes a pain to get it connected back up to WiFi, so I’ve created this little script to start hostapd and dnsmasq whenever the WiFi connection went down, which allowed me to SSH into the Pi even though it wasn’t connected to the network, because it was broadcasting it’s own network !

This can be customised to do different things if either WiFi or ethernet go down.

# Interface checker
# Checks to see whether interface has an IP address, if it doesn't assume it's down and start hostapd
# Author : SirLagz
echo "-----------------------------------"
echo "Checking connectivity of $Interface"
NetworkUp=`/sbin/ifconfig $Interface`
IP=`echo "$NetworkUp" | grep inet | wc -l`
if [[ $IP -eq 0 ]]; then
echo "Connection is down"
hostapd=`pidof hostapd`
if [[ -z $hostapd ]]; then
# If there are any more actions required when the interface goes down, add them here
echo "Attempting to start hostapd"
/etc/init.d/hostapd start
echo "Attempting to start dnsmasq"
/etc/init.d/dnsmasq start
echo "Setting IP Address for wlan0"
/sbin/ifconfig wlan0 $HostAPDIP netmask up
elif [[ $IP -eq 1 && $NetworkUp =~ $HostAPDIP ]]; then
echo "IP is $HostAPDIP - hostapd is running"
echo "Connection is up"
hostapd=`pidof hostapd`
if [[ ! -z $hostapd ]]; then
echo "Attempting to stop hostapd"
/etc/init.d/hostapd stop
echo "Attempting to stop dnsmasq"
/etc/init.d/dnsmasq stop
echo "Renewing IP Address for $Interface"
/sbin/dhclient wlan0
echo "-----------------------------------"

Aug 092012

** Quick Tip For The QuickLinks **
If you want a wifi router, ignore Part 2, and go from this part straight to Part 3. Need internet access ? Part 2 or 3 is the go depending on your need πŸ™‚
Part 2 – How to make your RPi into a Wireless Access Point
Part 3 – How to make your RPi into a Router

Also if you are using a RTL8188CUS based device check this forum thread
** Update – 2012-11-10 **
Looks like the newest version of the Raspbian distro adds an extra line to /etc/network/interfaces which needs to be removed or commented out.
The line is wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf
Thanks to hunternet93

** Update – 2016-11-06 **
As requested, I’ve added some information from the comments – courtesy of Jakimfett
To find out what driver your USB WiFi stick uses, you can use lshw -C network to find out. The driver info is shown under the configuration section. If lshw is not installed, you can install it via apt-get – apt-get install lshw

** Original Post Starts Here **

I recently bought a Wifi dongle for my Raspberry Pi – A Ralink RT5370.
While I was poking around, I noticed that the USB dongle could act as an Access Point.
I haven’t tried with any others, but the way I found out about mine is by using the iw utility.
Running iw list spat out a list of abilities.
This was a part of the list
Supported interface modes:
* managed
* AP
* monitor
* mesh point

So I decided to try it out.
I installed hostapd so that I could run an access point off the Raspberry Pi.
apt-get install hostapd

After I installed hostapd, I had to modify a few files before hostapd would run.

Before I go modifying the files though, I need to give my WiFi adapter a static IP address.
In /etc/network/ there is a file called interfaces. This file contains the details for the network adapters.
I have the lines below in order to set a static IP address.

iface wlan0 inet static

Now, we need to edit some files.
First up, I had to modify /etc/default/hostapd. The DAEMON_CONF variable was not configured, so I pointed it to a configuration file that I was about to create.

After that, I created the configuration file in the location specified.
In the configuration file, I specified the following parameters

# First we configure the interface we'll be listening on
interface=wlan0 # The interface to listen on
# The driver that is being used by the WiFi adapter, this could be different for everyone
ctrl_interface_group=0 # These 2 are just parameters so that the hostap daemon runs.

# Now onto the important WiFi configuration
# First up, the SSID or Network name. This is what other devices will see when they try to connect.
# I'm setting this to Wireless G mode. A, B, and G are available here.
# This is setting the channel that the WiFi is on, valid channels are from 1-11, or 1-14 depending on location.

# Wifi Security Settings
wpa=2 # This sets the security settings to WPA2
# The line above sets the wpa passphrase to "raspiwlan", this is obtained via the wpa_passphrase command.
# However, you can also set a passphrase like the line below.

# I've set these to WPA-PSK to indicate that we are using a Pre-Shared Key with CCMP encryption.
# Otherwise, hostapd also has a built in RADIUS server that we can use for authentcation
# But I'll leave that to another post.

# Other settings
beacon_int=100 # This sets how often the WiFi will send a beacon out.

** Note ** You may need to strip out all the comments when you save your configuration file as hostapd does not have consistent comment handling.

With the above configuration file saved, I downloaded dnsmasq in order to give my Raspberry Pi the ability to hand out IP addresses to clients that connected to the RaspAP.
apt-get install dnsmasq

For now, we’ll only do a base configuration of dnsmasq, just enough for it to hand out IP addresses so we can test out our new RasAP.

interface=wlan0 # To get dnsmasq to listen only on wlan0.
dhcp-range=,,,12h # This sets the available range from to
# It also sets the subnet mask to and specifies a lease time of 12 hours.

After the configuration file has been created in /etc/dnsmasq.conf, start up hostapd and restart dnsmasq.
You should now be able to see the WiFi network “RaspAP” and be able to connect to it and get an IP address.

In the next post, we will turn the Raspberry Pi into a bridge so that it can act as a wireless access point.

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