selftests: forwarding: Add a test for NH group stats

Add to lib.sh support for fetching NH stats, and a new library,
router_mpath_nh_lib.sh, with the common code for testing NH stats.
Use the latter from router_mpath_nh.sh and router_mpath_nh_res.sh.

The test works by sending traffic through a NH group, and checking that the
reported values correspond to what the link that ultimately receives the
traffic reports having seen.

Signed-off-by: Petr Machata <petrm@nvidia.com>
Link: https://lore.kernel.org/r/2a424c54062a5f1efd13b9ec5b2b0e29c6af2574.1709901020.git.petrm@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

selftests: forwarding: Parametrize mausezahn delay

The various multipath tests use mausezahn to generate different flows
and check how they are distributed between the available nexthops. The
tool is currently invoked with an hard coded transmission delay of 1 ms.
This is unnecessary when the tests are run with veth pairs and
needlessly prolongs the tests.

Parametrize this delay and default it to 0 us. It can be overridden
using the forwarding.config file. On my system, this reduces the run
time of router_multipath.sh by 93%.

Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Link: https://lore.kernel.org/r/20240304095612.462900-3-idosch@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

selftests: forwarding: Remove IPv6 L3 multipath hash tests

The multipath tests currently test both the L3 and L4 multipath hash
policies for IPv6, but only the L4 policy for IPv4. The reason is mostly
historic: When the initial multipath test was added
(router_multipath.sh) the IPv6 L4 policy did not exist and was later
added to the test. The other multipath tests copied this pattern
although there is little value in testing both policies.

Align the IPv4 and IPv6 tests and only test the L4 policy. On my system,
this reduces the run time of router_multipath.sh by 89% because of the
repeated ping6 invocations to randomize the flow label.

Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Link: https://lore.kernel.org/r/20240304095612.462900-2-idosch@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

selftests/net: Use kselftest skip code for skipped tests

There are several test cases in the net directory are still using
exit 0 or exit 1 when they need to be skipped. Use kselftest
framework skip code instead so it can help us to distinguish the
return status.

Criterion to filter out what should be fixed in net directory:
grep -r "exit [01]" -B1 | grep -i skip

This change might cause some false-positives if people are running
these test scripts directly and only checking their return codes,
which will change from 0 to 4. However I think the impact should be
small as most of our scripts here are already using this skip code.
And there will be no such issue if running them with the kselftest
framework.

Signed-off-by: Po-Hsu Lin <po-hsu.lin@canonical.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Tested-by: Ido Schimmel <idosch@nvidia.com>
Link: https://lore.kernel.org/r/20210823085854.40216-1-po-hsu.lin@canonical.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

selftests: forwarding: Specify interface when invoking mausezahn

Specify the interface through which packets should be transmitted so
that the test will pass regardless of the libnet version against which
mausezahn is linked.

Fixes: cab14d1087d9 ("selftests: Add version of router_multipath.sh using nexthop objects")
Fixes: 3d578d879517 ("selftests: forwarding: Test IPv4 weighted nexthops")
Signed-off-by: Danielle Ratson <danieller@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

selftests: forwarding: Add blackhole nexthops tests

Test that IPv4 and IPv6 ping fail when the route is using a blackhole
nexthop or a group with a blackhole nexthop. Test that ping passes when
the route starts using a valid nexthop.

Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

selftests: forwarding: Test IPv4 routes with IPv6 link-local nexthops

In addition to IPv4 multipath tests with IPv4 nexthops, also test IPv4
multipath with nexthops that use IPv6 link-local addresses.

Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

selftests: forwarding: Do not configure nexthop objects twice

routing_nh_obj() is used to configure the nexthop objects employed by
the test, but it is called twice resulting in "RTNETLINK answers: File
exists" messages.

Remove the first call, so that the function is only called after
setup_wait(), when all the interfaces are up and ready.

Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

selftests: Add version of router_multipath.sh using nexthop objects

Add a version of router_multipath.sh that uses nexthop objects for
routes.

Ido requested a version that does not cause regressions with mlxsw
testing since it does not support nexthop objects yet.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>