selftests: mlxsw: devlink_trap_tunnel_vxlan: Fix 'decap_error' case

Change the case that sends packets with "too short inner packet" to
include part of ethernet header, to make the trap to be triggered due to
the correct reason.

According to ASIC arch, the trap is triggered if overlay packet length is
less than 18B, and the minimum inner packet should include source MAC and
destination MAC.

Till now the case passed because one of the reserved bits in VxLAN
header was used. This issue was found while adding an equivalent test
for IPv6.

Signed-off-by: Amit Cohen <amcohen@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: mlxsw: Do not hard code trap group name

It can be derived dynamically from the trap's name, so drop it.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: pass pref and handle to devlink_trap_drop_* helpers

Currently the helpers assume pref 1 and handle 101. Make that explicit
and pass the values from callers.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: devlink_trap_tunnel_vxlan: Add test case for overlay_smac_is_mc

Test that the trap is triggered under the right conditions and that
devlink counters increase when action is trap.

Signed-off-by: Amit Cohen <amitc@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: devlink_trap_tunnel_vxlan: Add test case for decap_error

Test that the trap is triggered under the right conditions and that
devlink counters increase.

Signed-off-by: Amit Cohen <amitc@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>