Re: [PATCH net] selftests: forwarding: Fix failing tests with old libnet

[Jiri Pirko <jiri@nvidia.com>]

Tue, Aug 09, 2022 at 01:33:20PM CEST, idosch@nvidia.com wrote:
>The custom multipath hash tests use mausezahn in order to test how
>changes in various packet fields affect the packet distribution across
>the available nexthops.
>
>The tool uses the libnet library for various low-level packet
>construction and injection. The library started using the
>"SO_BINDTODEVICE" socket option for IPv6 sockets in version 1.1.6 and
>for IPv4 sockets in version 1.2.
>
>When the option is not set, packets are not routed according to the
>table associated with the VRF master device and tests fail.
>
>Fix this by prefixing the command with "ip vrf exec", which will cause
>the route lookup to occur in the VRF routing table. This makes the tests
>pass regardless of the libnet library version.
>
>Fixes: 511e8db54036 ("selftests: forwarding: Add test for custom multipath hash")
>Fixes: 185b0c190bb6 ("selftests: forwarding: Add test for custom multipath hash with IPv4 GRE")
>Fixes: b7715acba4d3 ("selftests: forwarding: Add test for custom multipath hash with IPv6 GRE")
>Reported-by: Ivan Vecera <ivecera@redhat.com>
>Tested-by: Ivan Vecera <ivecera@redhat.com>
>Signed-off-by: Ido Schimmel <idosch@nvidia.com>
>Reviewed-by: Amit Cohen <amcohen@nvidia.com>
>---
> .../net/forwarding/custom_multipath_hash.sh   | 24 ++++++++++++-------
> .../forwarding/gre_custom_multipath_hash.sh   | 24 ++++++++++++-------
> .../ip6gre_custom_multipath_hash.sh           | 24 ++++++++++++-------
> 3 files changed, 48 insertions(+), 24 deletions(-)
>
>diff --git a/tools/testing/selftests/net/forwarding/custom_multipath_hash.sh b/tools/testing/selftests/net/forwarding/custom_multipath_hash.sh
>index a15d21dc035a..56eb83d1a3bd 100755
>--- a/tools/testing/selftests/net/forwarding/custom_multipath_hash.sh
>+++ b/tools/testing/selftests/net/forwarding/custom_multipath_hash.sh
>@@ -181,37 +181,43 @@ ping_ipv6()
> 
> send_src_ipv4()
> {
>-	$MZ $h1 -q -p 64 -A "198.51.100.2-198.51.100.253" -B 203.0.113.2 \
>+	ip vrf exec v$h1 $MZ $h1 -q -p 64 \

Not directly related to this, but I was wondering, if it would be
possible to use $IP and allow user to replace the system-wide "ip" for
testing purposes...