I recently found a Linksys WRT56G version 2 wireless router amongst all of my things. This is really a fun piece of hardware and with the openwrt project runs linux like a dream!
root@OpenWrt:/etc# cat /proc/cpuinfo
system type : Broadcom BCM4712 chip rev 1
processor : 0
cpu model : BCM3302 V0.7
BogoMIPS : 197.42
The version 2 router has 4mb flash memory that you can play with. 2mb is used for the kernel, and you have approx 2mb to play with.
Everything i needed to do is done in the 2mb, but having more would of been fun. I ended up playing with chillispot, a captive portal. Essentially you can put up a wireless router, people pick up the ESSID and receive a DHCP address. Once they try browse, it redirects them to a login page.
So I could give free internet to those around me in my complex that can see my signal. I could plug this into phpmyprepaid and get them to buy internet time. Accounting is handled through freeradius with a mysql backend. There are many many docs on how to get this working, what my main problem was that I didnt understand how the openwrt / linksys vlans and ports worked. Furthermore, all the docs written assume that you use the Linksys to make your Internet connection. In my case i had
INTERNET---PPPOE MODEM----LINUX GATEWAY RUNNING PPPOE/FIREWALL/NAT ETC----LINKSYS and other PC's
So i needed to understand how to tell chillispot and openwrt to send the information through the LAN connection to my gateway to the internet.
Attached to this post are my config files. See this link to see a diagram of the Linksys V2 port layout. Notice that port 5 is the internal port and must be in all VLANS!
The files are for OpenWRT Kamikazi - I made the firewall change to ignore WAN ports and do the natting on the LAN (which i required for my setup).
Also, my current setup includes the options for WDS - so adding more routers into the equation. This could be quite useful. I would just add the bssid into the config/wireless option and hopefully they would connect.
take note you will have to change some values, mostly stuff in sql.conf and chill.conf and radius.conf
Thanks to many many forum articles, hotcakes hotspot manager documentation and the openwrt guys for making a cool os.