[P4-dev] Parsing a Protocol via pcap file and extracting the behavior of the packet

shubham bhardwaj bhardwajshubham2011 at gmail.com
Mon Dec 12 07:10:12 EST 2016


Hello Antonin,

Thanks for your reply, now i am getting some results. i am using
copy_to_cpu method and i want to store this parsed information in a file.
so do i need to implement a receiver or there is some other method. I am
sharing a screenshot of the output.

Regards

On Fri, Dec 2, 2016 at 8:34 PM, Antonin Bas <antonin at barefootnetworks.com>
wrote:

> Hi,
>
> Still unsure what you are trying to do. For me, parsing the packet *is*
> getting the information. If you need to store this information or process
> it outside of the switch, there are different things you can do:
> - you can store the information in stateful memories using the *register*
> construct. There is an example about using P4 registers here:
> https://github.com/p4lang/tutorials/tree/master/examples/register. The
> control plane can also access these stateful memories (read or write).
> - you can use learning to send the information to the CPU. Usually this is
> used to learn mac addresses when implementing a L2 switch. Learning is
> achieved in a P4 program using the generate_digest() action primitive.
> There is an example for this as well: https://github.com/p4lang/
> behavioral-model/blob/master/targets/l2_switch/l2_switch.p4. When doing
> learning you need to implement a receiver which will process these
> notifications. In the case of bmv2, there is an example of such a receiver
> here: https://github.com/p4lang/behavioral-model/blob/master/
> targets/l2_switch/learn_client/learn_client.cpp
> - you can simply redirect the whole packet to CPU. This is usually how
> protocol control packets (e.g. BGP) are processed (the control plane then
> populates the dataplane tables appropriately so that traffic is forwarded
> correctly). There is a basic example here: https://github.com/p4lang/
> tutorials/tree/master/examples/copy_to_cpu
>
> On Fri, Dec 2, 2016 at 1:06 AM, shubham bhardwaj <
> bhardwajshubham2011 at gmail.com> wrote:
>
>> Adding on, My last question was just simply how to give input of pcap
>> file in switch and i am able to that now. now i am trying to extract
>> information from that pcap file.
>>
>> Regards
>>
>> On Fri, Dec 2, 2016 at 10:02 AM, shubham bhardwaj <
>> bhardwajshubham2011 at gmail.com> wrote:
>>
>>> Hi Antonin,
>>>
>>> I need to analyse information from a packet, for that I am using Modbus
>>> protocol dumps. so basically i am parsing a Modbus Packet but as going
>>> through examples and p4 spec I am only able to modify the packet. So i just
>>> want to know is it possible to get the information from it and how. Is
>>> there any tutorial or demo present online.
>>>
>>> Thanks & Regards
>>> Shubham Bhardwaj
>>>
>>>
>>>
>>>  Sent with Mailtrack
>>> <https://mailtrack.io/install?source=signature&lang=en&referral=bhardwajshubham2011@gmail.com&idSignature=22>
>>>
>>> On Wed, Nov 30, 2016 at 6:24 PM, Antonin Bas <
>>> antonin at barefootnetworks.com> wrote:
>>>
>>>> Hi,
>>>>
>>>> I'm not sure I understand your question, or how it's different from the
>>>> last question you asked to the mailing list:
>>>> http://lists.p4.org/pipermail/p4-dev_lists.p4.org/2016-Novem
>>>> ber/000573.html
>>>> A little more details would be useful.
>>>>
>>>> Best,
>>>>
>>>> Antonin
>>>>
>>>> On Wed, Nov 30, 2016 at 5:14 AM, shubham bhardwaj <
>>>> bhardwajshubham2011 at gmail.com> wrote:
>>>>
>>>>> Hello All,
>>>>>
>>>>> I want to check the behavior of a packet(wireshark dump), Is it
>>>>> possible in P4. I have checked examples in the tutorial section and i
>>>>> haven't found anything relatable.
>>>>>
>>>>> --
>>>>> Thanks & Regards
>>>>> Shubham Bhardwaj
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> P4-dev mailing list
>>>>> P4-dev at lists.p4.org
>>>>> http://lists.p4.org/mailman/listinfo/p4-dev_lists.p4.org
>>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> Antonin
>>>>
>>>
>>>
>>>
>>> --
>>> Thanks & Regards
>>> Shubham Bhardwaj
>>> *Technical University of Darmstadt*
>>> +49 17641749766 <+49%20176%2041749766>
>>>
>>
>>
>>
>> --
>> Thanks & Regards
>> Shubham Bhardwaj
>> *Technical University of Darmstadt*
>> +49 17641749766 <+49%20176%2041749766>
>>
>
>
>
> --
> Antonin
>



-- 
Thanks & Regards
Shubham Bhardwaj
*Technical University of Darmstadt*
+49 17641749766
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