nl80211: use_monitor and non-mac80211 drivers

[Johannes Berg]

On Mon, 2016-11-14 at 14:00 +0200, Jouni Malinen wrote:

> Agreed.. There has been number of small changes to enable yet another
> combinations of driver capabilities to avoid accidentally hitting the
> monitor-based old design.
> 
> Getting rid of this code would also remove quite a bit of code:
>  src/drivers/driver_nl80211.c         | 127 ++-------
>  src/drivers/driver_nl80211.h         |  11 -
>  src/drivers/driver_nl80211_capa.c    |  12 +-
>  src/drivers/driver_nl80211_monitor.c | 491 -----------------------
> ------------
>  src/drivers/drivers.mak              |   1 -
>  5 files changed, 18 insertions(+), 624 deletions(-)

Yeah, I figured.

> 
> That said, it is still possible that someone is using this interface,
> so I'm not completely sure when it would be fine to remove this from
> hostapd/wpa_supplicant.. wpa_supplicant side might be safer thing to
> drop since P2P/AP mode support was likely added at around the same
> time as monitor interface design was replaced. For hostapd, it might
> be safer to make the support build configurable and disable that
> configuration parameter for at least one hostapd release by default
> to see if anyone notices..

Yeah, I guess that could be done. At some point, new features added to
hostapd will become irrelevant too though - nobody will have e.g. VHT
on such an old mac80211. So there's only limited value in using newer
hostapd binaries even, except perhaps for security fixes ...

johannes