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Hi Adrian,<br>
<br>
Thanks for your feedback regarding to your observation (cosmetic
nit).<br>
<br>
Regards,<br>
David DIALLO (Modbus pre-processor's author).<br>
<br>
<div class="moz-cite-prefix">Le 28/10/2014 15:51, Adrian Falk a
écrit :<br>
</div>
<blockquote
cite="mid:CAL+hx3K2iH8VrcfSRUeYQk1Hte=3=JAAjng6k5yrd67Tsxf-jA@mail.gmail.com"
type="cite">
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<div dir="ltr">Thanks Victor. This is exactly what I was looking
for.
<div><br>
</div>
<div>Following are an observation and a follow-up question.
<div><br>
</div>
<div>Observation: A cosmetic nit I saw when I pulled in the
modbus files and ran Suricata. In the file
app-layer-detect-proto.c add the following changes to fix
this cosmetic nit:</div>
<div>688,689d687</div>
<div> else if (pp_pe->alproto == ALPROTO_MODBUS)</div>
<div> printf(" alproto: ALPROTO_MODBUS\n");</div>
<div>739,740d736</div>
<div>
<div> else if (pp_pe->alproto == ALPROTO_MODBUS)</div>
<div> printf(" alproto: ALPROTO_MODBUS\n");</div>
</div>
<div><br>
</div>
<div><br>
</div>
<div>Follow-up question: Is there a file that you can point me
to that performs packet reassembly at L7. </div>
</div>
<div><br>
</div>
<div>Thanks.</div>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Fri, Oct 3, 2014 at 3:03 AM, Victor
Julien <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:victor@inliniac.net" target="_blank">victor@inliniac.net</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex"><span
class="">On 09/29/2014 05:01 PM, Adrian Falk wrote:<br>
> I am thinking about how to develop a Suricata
pre-processor for a TCP<br>
> based L7 protocol. I have looked at the Suricata
source code and have<br>
> also<br>
> reviewed <a moz-do-not-send="true"
href="https://redmine.openinfosecfoundation.org/projects/suricata/wiki/Packet_Inspection_Module"
target="_blank">https://redmine.openinfosecfoundation.org/projects/suricata/wiki/Packet_Inspection_Module</a><br>
<br>
</span>For this case, you'll need to use the app layer api
instead. Sadly, it's<br>
not documented yet.<br>
<span class=""><br>
> I have the following questions:<br>
><br>
> 1. Adding code as per the above document will allow
me to add new<br>
> keywords as well as allow me to perform protocol
packet boilerplate<br>
> checks (len, checksum, etc). Correct?<br>
><br>
> 2. How would I add support for protocol detection?<br>
><br>
> 3. How would I add stateful packet processing for the
L7 protocol?<br>
><br>
<br>
</span>I would like to suggest having a look at this work<br>
<a moz-do-not-send="true"
href="https://github.com/inliniac/suricata/pull/1134"
target="_blank">https://github.com/inliniac/suricata/pull/1134</a><br>
<br>
It does all that you ask for modbus.<br>
<span class="HOEnZb"><font color="#888888"><br>
--<br>
---------------------------------------------<br>
Victor Julien<br>
<a moz-do-not-send="true"
href="http://www.inliniac.net/" target="_blank">http://www.inliniac.net/</a><br>
PGP: <a moz-do-not-send="true"
href="http://www.inliniac.net/victorjulien.asc"
target="_blank">http://www.inliniac.net/victorjulien.asc</a><br>
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