TKIP for hostap

[Martin.Gergeleit at t-online.de]

Hi,

First of all: thanks for the great work on hostap!

We are seriously considering to add a TKIP crypt module to hostap
(Nobody else has done this before, right? And as far as I can can see,
there is no reason why this shouldn't work, right?). 

However, as far as I can see, the hostap_crypt interface can only be
used to do a part of the job as it only does the en/decryption of the
MPDU (i.e. the single frame/fragment that goes on air). But the
"michael" MIC is computed over the whole MSDU, i.e. a complete frame
that comes from/goes to the upper interface. Thus, at least two
additional hooks are required to perform these checks before and after
fragmentation. Any hints where this can be done best? Any other
important point that I am missing?

Thanks,
Martin