net: selftest: add test for netdev netlink queue-get API

Add a selftest for netdev generic netlink. For now there is only a
single test that exercises the `queue-get` API.

The test works with netdevsim by default or with a real device by
setting NETIF.

Add a timeout param to cmd() since ethtool -L can take a long time on
real devices.

Signed-off-by: David Wei <dw@davidwei.uk>
Link: https://lore.kernel.org/r/20240507163228.2066817-3-dw@davidwei.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

selftests: drv-net-hw: support using Python from net hw tests

We created a separate directory for HW-only tests, recently.
Glue in the Python test library there, Python is a bit annoying
when it comes to using library code located "lower"
in the directory structure.

Reuse the Env class, but let tests require non-nsim setup.

Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20240429144426.743476-3-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

selftests: drv-net: validate the environment

Throw a slightly more helpful exception when env variables
are partially populated. Prior to this change we'd get
a dictionary key exception somewhere later on.

Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20240425222341.309778-4-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

selftests: drv-net: reimplement the config parser

The shell lexer is not helping much, do very basic parsing
manually.

Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20240425222341.309778-3-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

selftests: drv-net: add require_XYZ() helpers for validating env

Wrap typical checks like whether given command used by the test
is available in helpers.

Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20240420025237.3309296-8-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

selftests: drv-net: add a TCP ping test case (and useful helpers)

More complex tests often have to spawn a background process,
like a server which will respond to requests or tcpdump.

Add support for creating such processes using the with keyword:

with bkg("my-daemon", ..):
# my-daemon is alive in this block

My initial thought was to add this support to cmd() directly
but it runs the command in the constructor, so by the time
we __enter__ it's too late to make sure we used "background=True".

Second useful helper transplanted from net_helper.sh is
wait_port_listen().

The test itself uses socat, which insists on v6 addresses
being wrapped in [], it's not the only command which requires
this format, so add the wrapped address to env. The hope
is to save test code from checking if address is v6.

Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20240420025237.3309296-7-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

selftests: drv-net: construct environment for running tests which require an endpoint

Nothing surprising here, hopefully. Wrap the variables from
the environment into a class or spawn a netdevsim based env
and pass it to the tests.

Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20240420025237.3309296-4-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

selftests: drv-net: factor out parsing of the env

The tests with a remote end will use a different class,
for clarity, but will also need to parse the env.
So factor parsing the env out to a function.

Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20240420025237.3309296-3-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

selftests: drivers: add scaffolding for Netlink tests in Python

Add drivers/net as a target for mixed-use tests.
The setup is expected to work similarly to the forwarding tests.
Since we only need one interface (unlike forwarding tests)
read the target device name from NETIF. If not present we'll
try to run the test against netdevsim.

Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>