[etherlab-users] ethercat filtering

[Sriram V]

Hello Mike,

I tried running a simple packet sniffer on a Laptop with 2 ethernet
interfaces. Still i am seeing the same behaviour.

On my laptop, I have 2 network interfaces eth0 and eth1. eth0 is the
lan and eth1 is the wlan.

I have created a raw socket and bound to eth0 using the below call.

setsockopt(sockfd, SOL_SOCKET, SO_BINDTODEVICE, ifName, strlen(ifName) + 1

I am listening for raw ethernet packets on the eth0. I am getting
packets even if i have removed the
lan cable. I am not sure how the packets from eth1 and sent to eth0?

My program is https://gist.github.com/austinmarton/2862515

I am not sure if there is any IP forwarding causing the issue. There
is a procfs regarding ip forwarding turning it off or on. does not
make any different.


Thanks for your help.

Regards,
Sriram

On Sat, Feb 11, 2017 at 3:54 PM, Mike O'Connor <mike at oeg.com.au> wrote:
> Hi Sriram
>
> So it sounds like you have the cabling wrong, Ethercat networks must be
> separated on a layer 2 network. Wired correctly you should never see the
> Ethercat frames on both networks.
>
> Mike
>
> On 10/02/2017 10:59 PM, Sriram V wrote:
>> Hi Mike,
>>
>> I have 2 ethernet ports. I am broadcasting ethercat packets on the
>> network. This is received by both the ports.
>> I want to allow ethercat packets ONLY to received by my raw socket
>> which is bound to one port.
>> On the other port - I want to allow ethernet packets with IP header
>> only (non ethercat packets).
>>
>> Is this possible.
>>
>> Thanks,
>> Sriram
>>
>> On Fri, Feb 10, 2017 at 12:31 PM, Mike O'Connor <mike at oeg.com.au> wrote:
>>> On 10/02/2017 4:59 PM, Sriram V wrote:
>>>> Hello,
>>>>
>>>> I wanted to check if i can allow only ethercat packets to be passed to
>>>> app layer?
>>>>
>>>> Basically, I want to process only ethercat packets.  Therefore, i want
>>>> to kernel to filter out basic IP packets.
>>>>
>>>> Regards,
>>>> Sriram
>>>> _______________________________________________
>>>> etherlab-users mailing list
>>>> etherlab-users at etherlab.org
>>>> http://lists.etherlab.org/mailman/listinfo/etherlab-users
>>> The Ethercat packets are actually raw Ethernet frames, so I think you
>>> need to explain what your issue is and from there the list might be able
>>> to help.
>>>
>>> Mike
>>>
>