Setting up interfaces in loopback mode using SIOCETHTOOL

Setting up interfaces in loopback mode using SIOCETHTOOL

[Ashutosh Tripathi]

Hi All,

In spite of several days of trying to get information out of ethtool
source code, I could not get a way to set the loopback mode for
network interfaces. I was also referring to the driver code for ixgbe
devices to get more info on the support it provides to ethtool. In the
driver code, there seems to be a way to set the loopback mode. But I
had no idea how to refer to this code from user space.

The SIOCETHTOOL is pretty general purpose. There is a way to test the
interface in loopback mode via the command line interface. But I just
wanted to set the interface in loopback mode so that I could send
packets on the interface myself and stress the interface.

Please help me with any suggestion in this regard.

Thanks,
----
Ashutosh

RE: Setting up interfaces in loopback mode using SIOCETHTOOL

[Skidmore, Donald C]

> -----Original Message-----
> From: netdev-owner@vger.kernel.org [mailto:netdev-
> owner@vger.kernel.org] On Behalf Of Ashutosh Tripathi
> Sent: Tuesday, June 16, 2015 3:52 AM
> To: netdev@vger.kernel.org
> Subject: Setting up interfaces in loopback mode using SIOCETHTOOL
> 
> Hi All,
> 
> In spite of several days of trying to get information out of ethtool source
> code, I could not get a way to set the loopback mode for network interfaces.
> I was also referring to the driver code for ixgbe devices to get more info on
> the support it provides to ethtool. In the driver code, there seems to be a
> way to set the loopback mode. But I had no idea how to refer to this code
> from user space.
> 
> The SIOCETHTOOL is pretty general purpose. There is a way to test the
> interface in loopback mode via the command line interface. But I just wanted
> to set the interface in loopback mode so that I could send packets on the
> interface myself and stress the interface.
> 
> Please help me with any suggestion in this regard.
> 
> Thanks,
> ----
> Ashutosh
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Hey Ashutosh,

Currently ixgbe only uses MAC loopback via the ethtool self_test, which doesn't sound like what you're looking for.  I don't know of an ethtool interface to tell an adapter to go into loopback mode, but this might just be because the driver I currently work on (ixgbe) doesn't support it. :)

Thanks,
-Don Skidmore <donald.c.skidmore@intel.com>