Re: [etherlab-users] ethercat filtering

[Sriram V]

Hi Mike,

You are right.

But that does not explain, Why the interface gets packets eventhough
the lan cable is removed.
So, i am trying to figure out if the program is wrong or is there
something going on which i am missing.

You could try this on a laptop as well. Not sure whats going on..

Regards,
Sriram



On Tue, Feb 14, 2017 at 4:51 PM, Mike O'Connor  wrote:
> On 14/02/2017 9:48 PM, Mike O'Connor wrote:
>> On 14/02/2017 9:41 PM, Sriram V wrote:
>>> Hi mike,
>>>
>>> I understand that. This is a totallyu different question and pertains
>>> to ethernet.
>>>
>>> I am just trying to find out on a normal ethernet network with 2
>>> interfaces whether a IP routing takes place.
>>> I am using a raw socket and seem to packets even though ifconfig does
>>> not show any increase in Rx Packets.
>>>
>> A raw socket is an IP packet with out any upper level protocol data, but
>> it does had ip addresses so depending on your computers configuration ip
>> packets can be routed between the two interfaces.
>>
>> But this mailing list is not the place for such a conversation, you need
>> to have a read of ip routing fundamentals.
>>
>>
>> Mike
>>
> Actually I'm wrong that example program uses raw Ethernet frames not raw
> ip packets so there no route-able.
>
>
> Mike
>
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Re: [etherlab-users] ethercat filtering

[Mike O'Connor]

On 14/02/2017 9:48 PM, Mike O'Connor wrote:
> On 14/02/2017 9:41 PM, Sriram V wrote:
>> Hi mike,
>>
>> I understand that. This is a totallyu different question and pertains
>> to ethernet.
>>
>> I am just trying to find out on a normal ethernet network with 2
>> interfaces whether a IP routing takes place.
>> I am using a raw socket and seem to packets even though ifconfig does
>> not show any increase in Rx Packets.
>>
> A raw socket is an IP packet with out any upper level protocol data, but
> it does had ip addresses so depending on your computers configuration ip
> packets can be routed between the two interfaces.
>
> But this mailing list is not the place for such a conversation, you need
> to have a read of ip routing fundamentals.
>
>
> Mike
>
Actually I'm wrong that example program uses raw Ethernet frames not raw
ip packets so there no route-able.


Mike

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Re: [etherlab-users] ethercat filtering

[Mike O'Connor]

On 14/02/2017 9:18 PM, Sriram V wrote:
> 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.

The Ethercat link must be on its own with a direct cable between the
PC's Ethernet and the EtherCAT device, which if needed is then daisy
chain to the next EtherCAT device.

Mike
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Re: [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  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  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
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>>> 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
>>>
>
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Re: [etherlab-users] ethercat filtering

[Mike O'Connor]

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  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@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
>>

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Re: [etherlab-users] ethercat filtering

[Sebastien Blanchet]

Hi Sriram,

Are you trying to write an EtherCAT slave for a device with a dual ethernet 
controller ?


Regards,
---
Sebastien


On 02/10/2017 01:29 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  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
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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

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Re: [etherlab-users] ethercat filtering

[Mike O'Connor]

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
> ___
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> etherlab-users@etherlab.org
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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

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