tree b7ecb90b14abd16341d34d0118f19da95ab15400
parent 9d71283328fbad680cc74d9b287580e373eb4d6c
author Jouni Malinen <j@w1.fi> 1350190366 -0700
committer Irfan Sheriff <isheriff@google.com> 1350233726 -0700

P2P: Improve robustness against lost ctrl::ack

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>