Re: Broken fragmentation

[Johannes Berg <johannes@sipsolutions.net>]

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On Thu, 2008-06-19 at 21:13 +0300, Tomas Winkler wrote:
> On Thu, Jun 19, 2008 at 6:26 PM, Johannes Berg
> <johannes@sipsolutions.net> wrote:
> > On Thu, 2008-06-19 at 17:45 +0300, Tomas Winkler wrote:
> >> On Thu, Jun 19, 2008 at 4:24 PM, Johannes Berg
> >> <johannes@sipsolutions.net> wrote:
> >> > On Thu, 2008-06-19 at 16:08 +0300, Tomas Winkler wrote:
> >> >> On Thu, Jun 19, 2008 at 3:23 PM, Johannes Berg
> >> >> <johannes@sipsolutions.net> wrote:
> >> >> >
> >> >> >> > Now it crashes in the driver...maybe the txinfo to cb changes. Looking into it.
> >> >> >> > Tomas
> >> >> >> Looks like this is the second part keyconf is null
> >> >> >
> >> >> > Part? You mean fragment? What encryption algorithm? I've quickly looked
> >> >> > and all of them seem to do the control.hw_key assignment in their
> >> >> > respective _skb handler so it should be done for all fragments.
> >> >>
> >> >> The problem is w/o crypto
> >> >> I think this is not set on each fragment
> >> >> info->flags |= IEEE80211_TX_CTL_DO_NOT_ENCRYPT;
> >> >
> >> > Ouch, you're right, the whole tx info isn't properly initialised for
> >> > fragments.
> >> >
> >> > Can you try putting
> >> >
> >> > memcpy(frag->cb, first->cb, sizeof(first->cb));
> >> >
> >> > at around line 690 of tx.c where this code is?
> >> >
> >> >                frag->priority = first->priority;
> >> >                skb_reserve(frag, tx->local->tx_headroom +
> >> >                                  IEEE80211_ENCRYPT_HEADROOM);
> >> >
> >> >
> >> > [now I know what the cause is. I had another patch that used skb_segment
> >> > to do the fragmentation, but that was dropped and skb_segment does copy
> >> > skb->cb while our code doesn't]
> >>
> >> No crash but still not at home. No fragmented traffic on the air...grrr.
> >
> > Hmm, ok. I'll give it a try later.
> 
> Fragments are in the air but the peer is not able to reassemble them.
> Something is wrong with the first fragment but I'm not sure yet.

Hm, ok. got a packet capture? Maybe that was broken before, I remember
having problems with fragmentation but putting it down to the
known-to-be-completely-broken AP I was using.

johannes

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