Got a piece of WRT54GS recently. It came with 32mb of ram. 16mb more ram than my current WRT54G! More ram = more stable? Something to be proven. At least, it is more stable for kismet.

After changing the firmware to OpenWRT (WhiteRussians), I was overwhelmed by the number of modified linux packages available for the system! I started installing lots of stuffs (using IPKG) and soon meet a deadend to my exploration. Insufficient disk space on the ‘/jffs’ mount. With some basic knowledge of Linux (knowledge courtesy of CS2106 - Operating Systems), I fiddled with samba and soon was on my way to explore more packages for the system. Below is my current disk status.

root@OpenWrt:~# df -h
Filesystem	Size	Used	Available	Use%	Mounted on
/dev/root	896.0k	896.0k	0	100%	/rom
none	7.0M	24.0k	7.0M	0%	/tmp
/dev/mtdblock/4	2.3M	1000.0k	1.3M	42%	/jffs
/jffs	896.0k	896.0k	0	100%	/
//192.168.168.10/ddwrt$	2.0G	14.5M	2.0G	1%	/tmp/samba

It is pretty simple to do all this.

Stuffs needed:

1.	Basic Linux knowledge (for SSH, editing of files and typing of commands)
2.	An available network share (full permission) with known username and password, server ip of the share and share name
3.	A WRT54G router with dd-wrt or openwrt firmware

Firstly, ensure that the needed packages for mapping network shares are installed

root@OpenWrt:~# ipkg list_installed | grep ^kmod-cifs
kmod-cifs - 2.4.30-brcm-5 - Kernel modules for CIFS support
root@OpenWrt:~#

If nothing is returned, install it

root@OpenWrt:~# ipkg install kmod-cifs

Try mapping the network share over,

root@OpenWrt:~# mkdir /tmp/samba
root@OpenWrt:~# mount -t cifs //<server ip>/<share name> /tmp/samba -o unc=\\\\<server ip>\\<share name>,user=<username>,pass=<password>

Now try writing to /tmp/samba and see if everything works fine. If you can write to and read from a file in /tmp/samba means that everything is working fine for you.

Bad news: stuffs on /tmp get wiped out every reboot. Means that samba folder would be gone and you would to type the two commands above everytime you reboot your router.

Good news: Custom startup script to the rescue!

You can either edit the startup script through the webif (web management) or through SSH. Add the following entries

1.	mkdir /tmp/samba &
2.	mount -t cifs //<server ip>/<share name> /tmp/samba -o unc=\\\\<server ip>\\<share name>,user=<username>,pass=<password> &
3.	echo dest smbfs /tmp/samba >> /etc/ipkg.conf &

Then type the following commands in the shell, just setting the PATH and LD_LIBRARY_PATH locations.

1.	root@OpenWrt:~# echo export PATH=$PATH:/tmp/samba/bin:/tmp/samba/sbin:/tmp/samba/usr/bin:/tmp/samba/usr/sbin >> /etc/profile
2.	root@OpenWrt:~# echo export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/lib:/usr/lib:/tmp/samba/lib:/tmp/samba/usr/lib >> /etc/profile

Remember to fill in the the required file denoted by < and > symbols. The last three commands is to allow you to install to your new samba drive as well as running applications off the samba drive. The startup script would help you run these everytime you reboot! Good news isn’t it?

Things to take note though, library files are best installed to jffs while others you can install onto your new samba (destination smbfs).

What do I meant by installing library files onto jffs? An example of installing a package (bitchx - IRC Client)

root@OpenWrt:~# ipkg info bitchx
Package: bitchx
Version: 1.1-1
Depends: libncurses
Status: install user installed
Section: net
Architecture: mipsel
maintainer: OpenWrt Developers Team
MD5Sum: 5d48b3a20fe8bc8849371a84ee5aed30
Size: 719661
Filename: bitchx_1.1-1_mipsel.ipk
Source: packages/net/bitchx
Description: popular IRC client

Successfully terminated.

Library packages starts with lib. Rule of (shadowandy’s) thumb, install libncurses (in this case) before installing bitchx package.

root@OpenWrt:~# ipkg install libncurses
root@OpenWrt:~# ipkg -d smbfs install bitchx

The first line without specifying the -d argument will install to /jffs by default. The second line has got ‘-d smbfs’ specified. Hence installation of the bitchx package will be onto /tmp/samba. Don’t understand why I do it this way? Try it yourself. Install everything onto smbfs will cause library linking problems. For simple packages, simply renaming works. For bigger ones, more stuffs need to be done inorder to make it work.

Time to explore more packages!

What? Kismet? You would need to compatible wireless adapter in order to do scanning!

Kismet? That WEP cracking software? You are trying to crack WEP keys?

Well, that are the few responses that people give after hearing you say Kismet. Well, I don’t have to worry about the wireless adapter when I am using the one onboard WRT54G. There is an openwrt packaged Kismet so it is bound to work! Kismet can be used for other purposes besides using it as a tool as part of the WEP cracking process. Like netstumbler, it can be used to discover wireless networks around your area so that you can avoid possible congested wireless channels (e.g channel 6). Some favored channels are 1, 6 and 11 as they doesn’t overlap each other resulting in lesser interference. But then channel 6 is so abused by the routers rolled out by our local ISP. With a simple scan, you can see 2wire and linksys routers all hogging on to channel 6. Channel 6 is also used for SuperG mode (108mbps), the reason I gave up on SuperG in my area is due to the congested channel.

Stop bullshitting. Running Kismet just to check for non-congested wireless channel?

The wireless on the 2nd hand WRT54G is much more stronger and sensitive than the one I had on my T43. Hence it is more viable to do a scan using the router than my notebook. Well, since I don’t have to bother about hardware compatibility issues now, perhaps for educational purposes I will try to crack a few WEP keys (on my DGL-4300). But before I do that, I would need to find other packages that is needed for the cracking as technically this router is the only linux system on my network, other than the ubuntu on my notebook. And perhaps do a SDcard mod on the router to increase its storage. Currently the storage is boosted by a 2GB samba share. Most softwares are installed on the 2GB share.

Ah, I’ve been poisoned by the newbie kernel hacking of Operating System module. Looking forward to compiling my own firmware. But that is after I get over the problem of bricking the router in the process of doing so.