Running driver tests

Running driver tests

Networking driver tests are executed within kselftest framework like any other tests. They support testing both real device drivers and emulated / software drivers (latter mostly to test the core parts of the stack).

SW mode

By default, when no extra parameters are set or exported, tests execute against software drivers such as netdevsim. No extra preparation is required the software devices are created and destroyed as part of the test. In this mode the tests are indistinguishable from other selftests and (for example) can be run using virtme-ng like the core networking selftests.

HW mode

Executing tests against a real device requires external preparation. The netdevice against which tests will be run must exist, be running (in UP state) and be configured with an IP address.

Refer to list of :ref:`Variables` later in this file to set up running the tests against a real device.

Both modes required

All tests in drivers/net must support running both against a software device and a real device. SW-only tests should instead be placed in net/ or drivers/net/netdevsim, HW-only tests in drivers/net/hw.

Variables

The variables can be set in the environment or by creating a net.config file in the same directory as this README file. Example:

$ NETIF=eth0 ./some_test.sh

or:

$ cat tools/testing/selftests/drivers/net/net.config
# Variable set in a file
NETIF=eth0

Please note that the config parser is very simple, if there are any non-alphanumeric characters in the value it needs to be in double quotes.

Local test (which don't require endpoint for sending / receiving traffic) need only the NETIF variable. Remaining variables define the endpoint and communication method.

NETIF

Name of the netdevice against which the test should be executed. When empty or not set software devices will be used.

LOCAL_V4, LOCAL_V6, REMOTE_V4, REMOTE_V6

Local and remote endpoint IP addresses.

REMOTE_TYPE

Communication method used to run commands on the remote endpoint. Test framework has built-in support for netns and ssh channels. netns assumes the "remote" interface is part of the same host, just moved to the specified netns. ssh communicates with remote endpoint over ssh and scp. Using persistent SSH connections is strongly encouraged to avoid the latency of SSH connection setup on every command.

Communication methods are defined by classes in lib/py/remote_{name}.py. It should be possible to add a new method without modifying any of the framework, by simply adding an appropriately named file to lib/py.

REMOTE_ARGS

Arguments used to construct the communication channel. Communication channel dependent:

for netns - name of the "remote" namespace
for ssh - name/address of the remote host

Example

Build the selftests:

# make -C tools/testing/selftests/ TARGETS="drivers/net drivers/net/hw"

"Install" the tests and copy them over to the target machine:

# make -C tools/testing/selftests/ TARGETS="drivers/net drivers/net/hw" \
   install INSTALL_PATH=/tmp/ksft-net-drv

# rsync -ra --delete /tmp/ksft-net-drv [email protected]:/root/

On the target machine, running the tests will use netdevsim by default:

[/root] # ./ksft-net-drv/run_kselftest.sh -t drivers/net:ping.py
TAP version 13
1..1
# timeout set to 45
# selftests: drivers/net: ping.py
# KTAP version 1
# 1..3
# ok 1 ping.test_v4
# ok 2 ping.test_v6
# ok 3 ping.test_tcp
# # Totals: pass:3 fail:0 xfail:0 xpass:0 skip:0 error:0
ok 1 selftests: drivers/net: ping.py

Create a config with remote info:

[/root] # cat > ./ksft-net-drv/drivers/net/net.config <<EOF
NETIF=eth0
LOCAL_V4=192.168.1.1
REMOTE_V4=192.168.1.2
REMOTE_TYPE=ssh
[email protected]
EOF

Run the test:

[/root] # ./ksft-net-drv/drivers/net/ping.py
KTAP version 1
1..3
ok 1 ping.test_v4
ok 2 ping.test_v6 # SKIP Test requires IPv6 connectivity
ok 3 ping.test_tcp
# Totals: pass:2 fail:0 xfail:0 xpass:0 skip:1 error:0

Dependencies

The tests have a handful of dependencies. For Fedora / CentOS:

dnf -y install netsniff-ng python-yaml socat iperf3