Messages in this thread | | | Subject | Re: [PATCH v2] 802.11n IBSS: wlan0 stops receiving packets due to aggregation after sender reboot | From | Johannes Berg <> | Date | Tue, 29 Oct 2019 10:07:30 +0100 |
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On Tue, 2019-10-29 at 09:54 +0100, Krzysztof Hałasa wrote:
> The problem I can see is that the dialog_tokens are 8-bit, way too small > to eliminate conflicts.
Well, they're also per station, we could just randomize the start and then we'd delete the old session and start a new one, on the receiver.
So that would improve robustness somewhat (down to a 1/256 chance to hit this problem).
> > Really what I think probably happened is that one of your stations lost > > the connection to the other, and didn't tell it about it in any way - so > > the other kept all the status alive. > > You must have missed my previous mail - I simply rebooted that station, > and alternatively rmmoded/modprobed ath9k. But the problem originated in > a station going out of and back in range, in fact.
I was on vacation, so yeah, quite possible I missed it.
Sounds like we need not just 4b08d1b6a994 ("mac80211: IBSS: send deauth when expiring inactive STAs")
but also send a deauth when we disconnect. Surprising we don't do that, actually.
> > I suspect to make all this work well we need to not only have the fixes > > I made recently to actually send and parse deauth frames, but also to > > even send an auth and reset the state when we receive that, so if we > > move out of range and even the deauth frame is lost, we can still reset > > properly. > > That's one thing. The other is a station trying ADDBA for the first time > after boot (while the local station has seen it before that reboot).
That's the situation though - the local station needs to know that it has in fact *not* seen the same instance of the station, but that the station has reset and needs to be removed & re-added.
> I guess we need to identify "new connection" reliably. Otherwise, > the new connections are treated as old ones and it doesn't work.
Right. But we can implement the (optional) authentication (which you actually already get when you implement [encrypted] IBSS with wpa_s), and reset the station state when we get an authentication frame.
johannes
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