rt25x0 Nintendo DS Client Driver

This is a work in progress. It currently does not work and only supports the rt2570 chipset.

This driver allows you to associate with a Nintendo DS hosting a WMB session. You can send and receive packets using a PF_PACKET and SOCK_DGRAM socket bound to the network interface.

The driver can also be used for hosting WMB sessions in the normal manner.

The source for the driver is here.

How the driver been hacked

Beacons

DSs send out beacon frames with a special Nintendo information element. To associate with them information held in this IE must be included in the Association Request. You can find more information here. The driver notices beacons with this IE and sets up the SSID for the request accordingly.

CF-Poll

This is the bit that does not work as I cannot get the driver to send out the response quickly enough. My understanding is be incomplete, any help welcome.

The DS host polls the client with data + CF-Poll frames. The client must reply to this poll in a timely manner (I believe this is about a window of 500 microseconds - a DS replys in around 200 microseconds).

The driver takes packets sent from the application and, if associated with a DS, places them on a special queue (Nin Data queue) so they are not transmitted immediately. Received frames are examined and if they are CF-Polls the driver will transmit the packet at the head of the Nin Data queue in a Data + CF-Ack frame. If the queue is empty a No Data + CF-Ack frmae is sent.

Getting the interface to associate

You associate with a DS in the same way as you would any access point. Bring the interface up and put it into managed mode if it is not already. Perform a scan (iwlist <if_name> scan). This does not always pick up the DS immediately in which case perform the scan again. Information regarding your DS should be displayed (its address will start with 00:09:bf). You can then associate with iwconfig <if_name> ap 00:09:bf:xx:xx:xx where the xx:xx:xx is replaced with the address returned by the scan.

If the interface is associated it will show the access point address when you run iwconfig.

Sometimes the interface will associate automatically, which is a bit annoying. I do not use wireless networks normally and not entirely sure how to control the association process.

Example Application

Here is an example application showing how to communicate using the driver. If you run the application whilst associated with (or just before associating) a DS it will print stuff letting you know it is working.