if_ral regression [was seq#'s on ap frames]

Sam Leffler sam at errno.com
Fri Jan 11 11:06:11 PST 2008

Sepherosa Ziehau wrote:
> On Jan 5, 2008 10:19 PM, Dag-Erling Smørgrav <des at des.no> wrote:
>> "Sepherosa Ziehau" <sepherosa at gmail.com> writes:
>>> This actually brings up two things:
>>> 1) I think we should ignore seq in multicast frames; this is permitted in
>>> 802.11 standard.  In dfly I did that, since one of our users
>>> encountered a broken commercial AP which is not 802.11e but uses
>>> different seq for data and beacon.
>>> 2) TX sequence.  I think standards only mention QSTA/nQSTA, but not
>>> AP.  Currently our AP uses per node TX seq, which means beacon's seq
>>> is difficult to choose, at least for 2560 based ral(4), whose beacons'
>>> seq need to be set by software.  I saw Linksys AP uses one seq for all
>>> of the frames it sends.  Sam, what's you opinion on this?
>>> I think if STA counts ral(4)'s beacon seq, as what we do currently,
>>> beacon missing will quickly happen since beacons will be discarded
>>> after first several data frames.
>> OK, I *think* I understood most of that.  Does this suggest a solution
>> to you?  I will try to get the wlandebug output tonight.
> I don't know whether you are still interested to track down the wired
> problem you had experienced.
> If you have time please try following patches:
> revert the old patch at your AP side and try this one
> http://people.freebsd.org/~sephe/rt2560_test.diff1
> apply following patch at you STA side
> http://people.freebsd.org/~sephe/ieee80211_input.c.diff
> Best Regards,
> sephe
[just back from holiday and only now caught your question about seq#'s]

The issue of seq# generation has mostly been ignored because many/most 
devices generate them directly.  I'm aware of issues w/ management 
frames not getting correct seq#'s for ap mode (e.g. probe response) and 
have some uncommitted changes.  Beacon frames should track the seq# in 
the bss node though there might be some trickiness w/ the bss node being 
rebuilt too much (we may need to propagate the current seq# as we do 
some other state).

On the rx side I'm not sure about ignoring seq# of mcast frames; it 
would definitely be a WAR for broken ap implementations.

FWIW I took ownership of a ral bug where AP mode tx just stopped for no 
apparent reason (I think it was probe response frames but can't 
recall).  This sounds like the same thing; can you check kern/117655?


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