• Luciano Coelho's avatar
    mac80211: only set CSA beacon when at least one beacon must be transmitted · 66e01cf9
    Luciano Coelho authored
    A beacon should never have a Channel Switch Announcement information
    element with a count of 0, because a count of 1 means switch just
    before the next beacon.  So, if a count of 0 was valid in a beacon, it
    would have been transmitted in the next channel already, which is
    useless.  A CSA count equal to zero is only meaningful in action
    frames or probe_responses.
    
    Fix the ieee80211_csa_is_complete() and ieee80211_update_csa()
    functions accordingly.
    
    With a CSA count of 0, we won't transmit any CSA beacons, because the
    switch will happen before the next TBTT.  To avoid extra work and
    potential confusion in the drivers, complete the CSA immediately,
    instead of waiting for the driver to call ieee80211_csa_finish().
    
    To keep things simpler, we also switch immediately when the CSA count
    is 1, while in theory we should delay the switch until just before the
    next TBTT.
    
    Additionally, move the ieee80211_csa_finish() function to cfg.c,
    where it makes more sense.
    Tested-by: default avatarSimon Wunderlich <sw@simonwunderlich.de>
    Acked-by: default avatarSimon Wunderlich <sw@simonwunderlich.de>
    Signed-off-by: default avatarLuciano Coelho <luciano.coelho@intel.com>
    Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
    66e01cf9
cfg.c 106 KB