Jouni Malinen j at w1.fi
Tue Nov 6 23:23:55 EST 2007

On Mon, Nov 05, 2007 at 04:57:11PM -0800, Ted Merrill wrote:
> After reviewing Atheros' wps_enrollee code plus the lastest hostap code,
> i've come to the conclusion that i should be using the wpa_ctrl interface in 
> my rewrite of wps_enrollee.

ctrl_iface is useful for number of cases, but I'm not sure that
wps_enrollee should be a completely separate program..

> Here is how it would work:
> -- wpa_supplicant already running
> -- separate software determines which writeless interface is being configured, 
> the ssid to use for configuration as well as the security mode to use (push 
> button or pin)
> -- wps_enrollee is run, being passed this information.
> -- wps_enrollee registers (via wpa_ctrl) to be called on assocation with ap.
> -- wps_enrollee tells wpa_supplicant (via wpa_ctrl interface) to associate the 
> interface in open mode (required for WPS).
> -- on association with ap, wps_enrollee state machine runs 
> -- when wps state machine is done and new configuration established,
> wps_enrollee optionally writes to file and optionally tells wps_supplicant 
> directly the new parameters (via wpa_ctrl).

What are the benefits of keeping wps_enrollee separate? As far as I can
tell, it seems to share lots of functionality and implementation with
wpa_supplicant and as such, it would likely add extra work for
maintaining the code and extra cost in program size if it were to remain

There may be some limits on resources that make it difficult to run two
programs that process EAPOL frames at the same time. For example,
NDISUIO on Windows XP does not support more than one program at a time
for receiving frames. Consequently, wpa_supplicant and wps_enrollee
could not use l2_packet_ndis.c at the same time.

Jouni Malinen                                            PGP id EFC895FA

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