Re: [PATCH net-next v2 3/3] selftests: net: add coverage for fdb nexthop dst port

[Ido Schimmel <idosch@nvidia.com>]

On Fri, Jul 17, 2026 at 06:45:18AM +0000, Jack Ma wrote:
> Add fib_nexthops_fdb_port.sh, which exercises the NHA_FDB_PORT rules:
> accept a port on an fdb nexthop that has a gateway and echo it back on
> dump, reject it on non-fdb or gateway-less nexthops, allow a group whose
> legs differ only in UDP port, and confirm a portless fdb nexthop omits
> the attribute.  The test SKIPs cleanly on kernels or iproute2 without
> NHA_FDB_PORT support.

We already have control plane test for FDB nexthops in fib_nexthops.sh,
can you add the new test cases there instead? Probably fit in
ipv4_fdb_grp_fcnal() and ipv6_fdb_grp_fcnal()

> 
> Signed-off-by: Jack Ma <jack4it@gmail.com>
> ---
>  tools/testing/selftests/net/Makefile               |  1 +
>  .../testing/selftests/net/fib_nexthops_fdb_port.sh | 78 ++++++++++++++++++++++
>  2 files changed, 79 insertions(+)
> 
> diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile
> index 708d960ae..c06eb4927 100644
> --- a/tools/testing/selftests/net/Makefile
> +++ b/tools/testing/selftests/net/Makefile
> @@ -36,6 +36,7 @@ TEST_PROGS := \
>  	fib_nexthop_multiprefix.sh \
>  	fib_nexthop_nongw.sh \
>  	fib_nexthops.sh \
> +	fib_nexthops_fdb_port.sh \
>  	fib_rule_tests.sh \
>  	fib_tests.sh \
>  	fin_ack_lat.sh \
> diff --git a/tools/testing/selftests/net/fib_nexthops_fdb_port.sh b/tools/testing/selftests/net/fib_nexthops_fdb_port.sh
> new file mode 100755
> index 000000000..8b401c6d2
> --- /dev/null
> +++ b/tools/testing/selftests/net/fib_nexthops_fdb_port.sh
> @@ -0,0 +1,78 @@
> +#!/bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +#
> +# Control-plane selftest for per-nexthop VXLAN fdb destination port
> +# (NHA_FDB_PORT).  Verifies the accept/reject rules and the dump roundtrip.
> +# No datapath traffic here -- see tests/integ/vxlan-fdb-port-integ.sh for the
> +# real forwarding test.

vxlan-fdb-port-integ.sh doesn't exist. We have test_vxlan_nh.sh. Can you
extend basic_tx_common() to test the new attribute? Don't change the
existing configuration (we want to test the configuration where user
space doesn't pass a port) and instead add a new:

1. FDB nexthop and a group that contains it
2. Flower filter that also matches on the destination port (not 4789)
3. FDB entry that points to the new group

Run shellcheck (preferably via ingest_mdir.py [1]) to make sure you're
not adding new warnings / errors.

[1] https://github.com/linux-netdev/nipa#running-locally