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)

Debian                                           August 4, 2009                               IEEE80211_BMISS(9)