• Jouni Malinen's avatar
    P2P: Improve robustness against lost ctrl::ack · 2c5b17df
    Jouni Malinen authored
    P2P includes two use cases where one of the devices is going to start a
    group and likely change channels immediately after processing a frame.
    This operation may be fast enough to make the device leave the current
    channel before the peer has completed layer 2 retransmission of the
    frame in case the ctrl::ack frame was lost. This can result in the peer
    not getting TX status success notification.
    
    For GO Negotiation Confirm frame, p2p_go_neg_conf_cb() has a workaround
    that ignores the TX status failure and will continue with the group
    formation with the assumption that the peer actually received the frame
    even though we did not receive ctrl::ack. For Invitation Response frame
    to re-invoke a persistent group, no such workaround is used in
    p2p_invitation_resp_cb(). Consequently, TX status failure due to lost
    ctrl::ack frame results in one of the peers not starting the group.
    
    Increase the likelihood of layer 2 retransmission getting acknowledged
    and ctrl::ack being received by waiting a short duration after having
    processed the GO Negotiation Confirm and Invitation Response frames for
    the re-invocation case. For the former, use 20 ms wait since this case
    has been worked around in deployed devices. For the latter, use 50 ms
    wait to get even higher likelihood of getting ctrl::ack through since
    deployed devices (and the current wpa_supplicant implementation) do not
    have a workaround to ignore TX status failure.
    
    20 ms is long enough to include at least couple of retries and that
    should increase likelihood of getting ctrl::ack through quite a bit. The
    longer 50 ms wait is likely to include full set of layer 2 retries.
    
    Bug: 7282991
    Change-Id: If063895046ff42fb52579bfb386281085bedce58
    Signed-hostap: Jouni Malinen <jouni@qca.qualcomm.com>
    2c5b17df
p2p_supplicant.c 151 KB