[ath9k-devel] limited interface of mac80211 to drivers

[Daniel Smith <viscous.liquid@gmail.com>]

Hi Abhiav,

On 2/21/2012 11:42 PM, abhinav narain wrote:
> hi,
> I am working on ath9k device driver.
> I want to pass some driver data to the userspace
> the most crucial point is transferring skbuff from  ath_rx_tasklet() to
> ieee80211_rx() using struct ath_hw.
>
> But there is no way to pass any extra information ... is there any void *
> variable where I can store the data of ath9k driver and receive it in
> mac80211 subsystem ?
> I can then transfer it to userspace easily.
I had a similar issue and the approach I took was to add a vendor 
radiotap header to the beginning of the skb buffer in ath9k. Then in 
mac80211 I combined the vendor radiotap header with the main radiotap 
header added by mac80211. The gotcha to watch out for is that you need 
to ensure enough space is allocated in the skb.
>
> I have another doubt with the evolving kernel subsystem,  I cannot use
> ioctl calls to set a particular channel to listen to ?
> And I am still using raw socket to read the frame in userspace ...
> any hints regarding this will be very helpful
Ath9k is a mac80211 based driver, you should be using the cfg80211 
netlink-based API to control the device. Actually you should use it for 
all wireless devices because the WEXT ioctl framework is deprecated. As 
for the raw socket, if you are looking for an API to abstract the packet 
sniffing then take a look at libpcap.

v/r,
dps