June 8 2002

AP Radar is a wireless utility that stumbles, manages associations to access points, makes authorization requests wireless gateways, and does a little peer-2-peer communication.

The problem its trying to solve is that AccessPoint association in linux is too manual.

You want to use an access point. Open an xterm. Do you know the essid? BR Yes go to a1. BR No go to b1.BR

Physical Layer

I know the essid of the access point I want to use. BR a1) set the essid to the essid of the access point go to step c1

I dont know the essid of the access point I want to use.BR b1) use iwconfig to set the essid to any. this is usually already the case

b2) see which AP your driver/card has picked up on. shold be the strongest signal. go to step c1. If you have an idea of what the essid name is and this isnt it, you are screwed.

c1) is the signal strength is adequate? yes - go to step d1. no - you are screwed.

Network Layer

d1) aquire an IP address by running a dhcp client such as pump. wait for an answer.

d2) ping the gateway, test the DNS service. good - go to step e1. no - you are screwed.

Authentication Layer

e1) send a broadcast request for the authenticaton server on this segment. Used to locate a nocat or metanet "gateway access service". Use BroadcastXml for this.

e2) send an xml-rpc authentication request to the server, if no broadcast answer, use the ip of the default gateway.

Other

Once you're connected. Keep a constant monitor of the associated AP. My cisco card has the very annoying habbit of switching to a stronger AP, even with a different essid, whenever it feels the need. Also keep a constant monitor of the access points in range. OS X is a great example of how this should work.

Use BroadcastXml to have AP radar discover any other boxes on the segment that are running AP Radar.

implementation

idea 1. Have steps a through d in a Gnome component. Pro: Then it could be plugged into lots of other gnome apps easily. Con: Id have to write in c++

idea 2. A java applet. Pro: Im already proficient in java. Con: Difficult to talk to glibc/kernel. Many people dont have java installed

idea 3. a gnome toolbar applet.

Stumbling BR

• Stumbling will involve a lot of custom code, ugly hacks, and possibly promiscious mode. This is whats required in the 2.4 kernel series of pcmcia-cs. The 2.5-era pcmcia-cs has functions in the API to get a list of all APs in range.

DonPark

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