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NAME

     ieee80211_bmiss - 802.11 beacon miss support

SYNOPSIS

     #include <net80211/ieee80211_var.h>

     void
     ieee80211_beacon_miss(struct ieee80211com *);

DESCRIPTION

     The net80211 software layer provides a support framework for drivers that
     includes handling beacon miss events in station mode.  Drivers can
     dispatch beacon miss events that are recognized in hardware or net80211
     can detect beacon miss if the driver dispatches received beacon frames
     through the normal receive path.  Software beacon miss support is
     especially useful when multiple vaps are operating and any hardware
     beacon miss support is not available (e.g. operating as an access point
     together with one or more station mode vaps).

     Drivers should dispatch beacon miss events recognized in the driver with
     ieee80211_beacon_miss().  This causes some number of ProbeRequest frames
     to be sent to the access point to check if the association is still
     alive.  If no response is received and roaming mode is set to
     IEEE80211_ROAMING_AUTO then net80211 will try to re-associate and if that
     fails trigger a scan to look for the access point or another suitable AP.
     When the net80211 state machine is being operated manually, e.g. by
     wpa_supplicant(8), then applications are notified of the state change and
     are responsible for handling the work of scanning for a new access point.
     The number of beacon miss events (without a ProbeResponse) is user
     settable with the IEEE80211_IOC_BMISSTHRESHOLD request.

     Software beacon miss detection is enabled per-vap by setting the
     IEEE80211_FEXT_SWBMISS flag.  Typically this is done when a vap is setup
     when the IEEE80211_CLONE_NOBEACONS option is supplied to the clone
     operation.  But drivers may also force this when they know they need help
     detecting beacon miss.  When beacon miss is detected in software the
     event is dispatched without driver involvement.  Note that software
     beacon miss handling is not limited to station mode; it can be used in
     any operating mode where beacons from a peer station are received.

SEE ALSO

     wpa_supplicant(8), ieee80211(9), ieee80211_vap(9)