Add some more functionality for BSS Transition Management:
- advertise support for BSS Transition Management in extended
capabilities element
- add hostapd.conf parameter bss_transition=1 for enabling support
for BSS Transition Management
- add "hostapd_cli disassoc_imminent <STA> <num TBTTs>" for sending
disassociation imminent notifications for testing purposes
- wpa_supplicant: trigger a new scan to find another BSS if the
current AP indicates disassociation imminent (TODO: the old AP needs
to be marked to use lower priority to avoid re-selecting it)
Signed-hostap: Jouni Malinen <j@w1.fi>
Replace CONFIG_IEEE80211V with CONFIG_WNM to get more consistent build
options for WNM-Sleep Mode operations. Previously it was possible to
define CONFIG_IEEE80211V without CONFIG_WNM which would break the build.
In addition, IEEE 802.11v has been merged into IEEE Std 802.11-2012 and
WNM is a better term to use for this new functionality anyway.
Signed-hostap: Jouni Malinen <j@w1.fi>
