Re: [PATCH net-next] net: Allow ethtool to set interface in loopback mode.

[Mahesh Bandewar <maheshb@google.com>]

On Wed, Apr 27, 2011 at 11:08 PM, David Miller <davem@davemloft.net> wrote:
>
> From: Mahesh Bandewar <maheshb@google.com>
> Date: Wed, 20 Apr 2011 17:57:38 -0700
>
> > This patch enables ethtool to set the loopback mode on a given interface.
> > By configuring the interface in loopback mode in conjunction with a policy
> > route / rule, a userland application can stress the egress / ingress path
> > exposing the flows of the change in progress and potentially help developer(s)
> > understand the impact of those changes without even sending a packet out
> > on the network.
> >
> > Following set of commands illustrates one such example -
> >     a) ip -4 addr add 192.168.1.1/24 dev eth1
> >     b) ip -4 rule add from all iif eth1 lookup 250
> >     c) ip -4 route add local 0/0 dev lo proto kernel scope host table 250
> >     d) arp -Ds 192.168.1.100 eth1
> >     e) arp -Ds 192.168.1.200 eth1
> >     f) sysctl -w net.ipv4.ip_nonlocal_bind=1
> >     g) sysctl -w net.ipv4.conf.all.accept_local=1
> >     # Assuming that the machine has 8 cores
> >     h) taskset 000f netserver -L 192.168.1.200
> >     i) taskset 00f0 netperf -t TCP_CRR -L 192.168.1.100 -H 192.168.1.200 -l 30
> >
> > Signed-off-by: Mahesh Bandewar <maheshb@google.com>
>
> It's impossible to evaluate this patch without you also showing us some
> users.
>
My apologies. I'll post one such case/patch immediately.

--mahesh..

> I'm not applying this.