[WIP][ref] IBSS-RSN: Detect node reboots with open system auth.

[Nicolas Cavallari]

As discussed on linux-wireless, here are some work in progress for
node reboot detection in userspace instead of doing it in the kernel.
This requires changes to the kernel that have not been integrated.

These patches let wpa_supplicant do node reboot detection using
open system authentication, instead of doing it in the kernel.

These patches will only soft-reset stations when receiving an
auth 1/2 from stations that have sent at least one EAPOL frame to us.
It will also not perform open system authentication on hosts that
have sent EAPOL frames directly or are already performing open system
authentication.

This is still mostly incomplete and hacky:
- It is enabled unconditionnaly.
- Deauth frames are left to the kernel.
- Some error conditions are not checked (e.g.  receiving invalid EAPOL
  frames)
- Some log messages are not clear.
- And I haven't tested that version (I just removed unrelated bloat).


 src/drivers/driver_nl80211.c |   13 ++-
 wpa_supplicant/events.c      |   26 +++++-
 wpa_supplicant/ibss_rsn.c    |  197 +++++++++++++++++++++++++++++++++++++-----
 wpa_supplicant/ibss_rsn.h    |   14 +++
 4 files changed, 227 insertions(+), 23 deletions(-)