wpa_supplicant: how to inform AP of Sleep Mode
Mon Oct 12 00:41:40 PDT 2009
> I think wpa_supplicant uses some type of MAC frame (for example
> for probe request, right?).
wpa_supplicant asks the kernel driver via it
src/drivers/driver_*.c files to do the scanning.
The kernel driver will then send probe requests (if it's an
active scan). It will also be the job of the kernel driver to
send a NUL-packet (802.11 packet without actual data), but with
the power-save bit set in the 802.11 flags). This will make that
the receiving AP assumes the station is sleeping and make the AP
buffer packets for the station (and more).
> So I believed there's a way to inform AP of the intention of
> going to sleep (modifying source code, of course)
Not from user-space. Wpa_supplicant can't send this packet
Some WLAN cards, e.g. fullmac cards based on the libertas driver,
have a firmware where you can't even ask the firmware to send
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