On Fri, Aug 11, 2023 at 05:59:27PM +0200, Petr Machata wrote:
+ Shuah Khan <shuah@xxxxxxxxxx>, linux-kselftest@xxxxxxxxxxxxxxx
> This test verifies whether the encapsulated packets have the correct
> configured TTL. It does so by sending ICMP packets through the test
> topology and mirroring them to a gretap netdevice. On a busy host
> however, more than just the test ICMP packets may end up flowing
> through the topology, get mirrored, and counted. This leads to
> potential spurious failures as the test observes much more mirrored
> packets than the sent test packets, and assumes a bug.
>
> Fix this by tightening up the mirror action match. Change it from
> matchall to a flower classifier matching on ICMP packets specifically.
>
> Fixes: 45315673e0c5 ("selftests: forwarding: Test changes in mirror-to-gretap")
> Signed-off-by: Petr Machata <petrm@xxxxxxxxxx>
> Tested-by: Mirsad Todorovac <mirsad.todorovac@xxxxxxxxxxxx>
> Reviewed-by: Ido Schimmel <idosch@xxxxxxxxxx>
Reviewed-by: Simon Horman <horms@xxxxxxxxxx>
> ---
> tools/testing/selftests/net/forwarding/mirror_gre_changes.sh | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/net/forwarding/mirror_gre_changes.sh b/tools/testing/selftests/net/forwarding/mirror_gre_changes.sh
> index aff88f78e339..5ea9d63915f7 100755
> --- a/tools/testing/selftests/net/forwarding/mirror_gre_changes.sh
> +++ b/tools/testing/selftests/net/forwarding/mirror_gre_changes.sh
> @@ -72,7 +72,8 @@ test_span_gre_ttl()
>
> RET=0
>
> - mirror_install $swp1 ingress $tundev "matchall $tcflags"
> + mirror_install $swp1 ingress $tundev \
> + "prot ip flower $tcflags ip_prot icmp"
> tc filter add dev $h3 ingress pref 77 prot $prot \
> flower skip_hw ip_ttl 50 action pass
>
> --
> 2.41.0
>
>
