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Wireshark-dev: Re: [Wireshark-dev] wireshark -- atm n:1 dissector

From: Francesco Fondelli <francesco.fondelli@xxxxxxxxx>
Date: Wed, 8 Apr 2009 17:30:00 +0200
On Tue, Apr 7, 2009 at 4:17 PM, Tamazov, Artem
<artem.tamazov@xxxxxxxxxxx> wrote:
>
> Hello Francesco,

Hi Artem,

first of all thanks for making my PW dissection framework better
than the original :-)

> Recently I've implemented ATM N:1 dissection and get into merge conflict
> after SVN merge.
> It looks that we have the same plans regarding Wireshark ;)
> I mean:
>     DONE:
>         - ATM N-to-One Cell Mode (with CW)
>         - ATM N-to-One Cell Mode (no CW)
>     TODO:
>         - ATM One-to-One Cell Mode
>         - ATM AAL5 SDU Mode
>         - ATM AAL5 PDU Mode

:-)

> Well, let's decide how to handle this.
>
> It first glance, my implementation hase more features related to validation
> of packets.

yes

> Also it supports some old equipment (it has a couple of options for this).

I didn't know someone was using CW length/reserved bits with a value != 0, if
they use the length to determine if a packet is valid or not they will have
some interoperability problems, it is nice that WS is able to highlight it.

> Your implementation more extensively uses existing ATM dissector, which is
> important.

filter for ATM and ATM fields is a MUST, IMHO, given the fact that there are
ATM cells within that PW.  I had to call the ATM dissector and put part
of the work there.  This looked to me the more appropriate way to accomplish
the task.  Any idea from WS people?

> For now I am going to look at your ATM PW dissector with more attention.
> Also I would like you to look at my code.
> Then we can decide how to resolve this situation.
>

ok no problem

> If you agree, I will send my patches to you (I will prepare them so you will
> not experience merge conflicts).

thanks

> What is your opinion?

a) re-spin your patch using mine as a base and get good things from
both approaches
b) revert mine (a part of it, i.e. packet-pw-eth.c is fine as it is
now, don't revert
   packet-atm.c stuff about NNI dissection option because this is fine
'per se') and apply
   your patch.

Any core WS developer opinion?

> Regards,
> Artem Tamazov//

thanks
Ciao
FF