"Robert P. J. Day" <rpj...@crashcourse.ca> writes:
> (i'm sure this has been explained many times before, so a link
> covering this will almost certainly do just fine.)
>
> i want to loop one physical ethernet port into another, and just
> ping the daylights from one to the other for stress testing. my fedora
> laptop doesn't actually have two unused ethernet ports, so i just want
> to emulate this by slapping a couple startech USB/net adapters into
> two empty USB ports, setting this up, then doing it all over again
> monday morning on the actual target system, which does have multiple
> ethernet ports.
[...]
I used this in the past to test dual-port NIC over loopback cable, you
will need to ajust the script:
#!/bin/bash -x
ip="sudo $HOME/bin/ip"
eth1=192.168.2.100
eth2=192.168.2.101
dev1=eth1
dev2=eth2
dev1mac=00:1b:21:9b:24:b4
dev2mac=00:1b:21:9b:24:b5
# fake client interfaces and addresses
dev=dummy0
dev_mac=00:00:00:00:00:11
# max fake clients supported for simulation
maxusers=3
## Create dummy device
## Accepted parameters:
## $1 - devname
## $2 - devmac
## $3 - subnet (e.g. 10.10.10)
## $4 - max number of IP addresses to create on interface
setup_dummy()
{
# sudo sh -c "echo 1 > /proc/sys/net/ipv4/ip_forward"
# Enable tc hardware offload
# ethtool -K $SGW_DEV hw-tc-offload on
$ip link add $1 address $2 type dummy
$ip link set $1 up
for i in `seq 1 $4`;
do
$ip addr add $3.$i/32 dev $1
done
}
## Delete dummy device
## Accepted parameters:
## $1 - devname
delete_dummy()
{
$ip link del $1 type dummy
}
setup_network()
{
# Send traffic eth3 <-> eth4 over loopback cable, where both interfaces
# eth3 and eth4 are in the same subnet.
#
# We assume that NetworkManager is not running and eth3/eth4 are configured
# via /etc/network/interfaces:
#
# 192.168.1.100/32 dev eth3
# 192.168.1.101/32 dev eth4
#
# Specify source IP address when sending the traffic:
# ping -I 192.168.1.100 192.168.1.101
#
#
$ip neigh add $eth2 lladdr $dev2mac nud permanent dev $dev1
$ip neigh add $eth1 lladdr $dev1mac nud permanent dev $dev2
$ip route add table main $eth1 dev $dev2
$ip route add table main $eth2 dev $dev1
$ip rule add from all lookup local pref 100
$ip rule del pref 0
$ip rule add from $eth2 to $eth1 iif $dev1 lookup local pref 1
$ip rule add from $eth1 to $eth2 iif $dev2 lookup local pref 2
$ip rule add from $eth2 to $eth1 lookup main pref 3
$ip rule add from $eth1 to $eth2 lookup main pref 4
# $ip rule add from 10.10.10.0/24 to $eth1 iif $dev1 lookup local pref 5
# $ip rule add from 10.10.10.0/24 to $eth2 iif $dev2 lookup local pref 6
# $ip rule add from $eth1 to 10.10.10.0/24 iif $dev2 lookup local pref 7
# $ip rule add from $eth2 to 10.10.10.0/24 iif $dev1 lookup local pref 8
}
restore_network()
{
# FIX: hangs connections
$ip rule flush
$ip rule add priority 32767 lookup default
}
#delete_dummy dummy0
#delete_dummy dummy1
#setup_dummy dummy0 00:00:00:00:00:11 10.10.10 3
#setup_dummy dummy1 00:00:00:00:00:22 20.20.20 3
setup_network
