Re: [PATCHv2 1/2] net: Allow ethtool to set interface in loopback mode.

[David Miller <davem@davemloft.net>]

From: Ben Hutchings <bhutchings@solarflare.com>
Date: Thu, 05 May 2011 02:52:48 +0100

> On Wed, 2011-05-04 at 18:30 -0700, Mahesh Bandewar wrote:
>> 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>
> Acked-by: Ben Hutchings <bhutchings@solarflare.com>

Applied.