Re: Broken fragmentation

["Tomas Winkler" <tomasw@gmail.com>]

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.
Tomas