Subject: Re: [PATCH v2 2/2] selftests/bpf: integrate test_xdp_veth into test_progs

From: Simon Horman <[email-masked]>
Date: Mon, 15 Jul 2024 13:27:37 +0100

On Mon, Jul 15, 2024 at 11:53:45AM +0200, Alexis Lothoré (eBPF Foundation) wrote:
> test_xdp_veth.sh tests that XDP return codes work as expected, by bringing
> up multiple veth pairs isolated in different namespaces, attaching specific
> xdp programs to each interface, and ensuring that the whole chain allows to
> ping one end interface from the first one. The test runs well but is
> currently not integrated in test_progs, which prevents it from being run
> automatically in the CI infrastructure.
> 
> Rewrite it as a C test relying on libbpf to allow running it in the CI
> infrastructure. The new code brings up the same network infrastructure and
> reuses the same eBPF programs as test_xdp_veth.sh, for which skeletons are
> already generated by the bpf tests makefile.
> 
> Signed-off-by: Alexis Lothoré (eBPF Foundation) <[email-masked]>
> ---
> The new code has been tested in an aarch64 qemu instance:
> Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED
> 
> I have also checked that some minor alterations in the network
> configuration (altering the redirect map, or not loading one of the xdp
> programs) make the test fail.
> 
> On my testing setup, the test takes a bit more than 3 seconds to run on
> average.
> 
> Changes in v2:
> - fix many formatting issues raised by checkpatch
> - use static namespaces instead of random ones
> - use SYS_NOFAIL instead of snprintf() + system ()
> - squashed the new test addition patch and the old test removal patch
> ---
>  tools/testing/selftests/bpf/Makefile               |   1 -
>  .../selftests/bpf/prog_tests/test_xdp_veth.c       | 211 +++++++++++++++++++++
>  tools/testing/selftests/bpf/test_xdp_veth.sh       | 121 ------------
>  3 files changed, 211 insertions(+), 122 deletions(-)
> 
> diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
> index a7932bead77d..2864a0dc04d5 100644
> --- a/tools/testing/selftests/bpf/Makefile
> +++ b/tools/testing/selftests/bpf/Makefile
> @@ -117,7 +117,6 @@ TEST_PROGS := test_kmod.sh \
>  	test_xdp_redirect.sh \
>  	test_xdp_redirect_multi.sh \
>  	test_xdp_meta.sh \
> -	test_xdp_veth.sh \
>  	test_tunnel.sh \
>  	test_lwt_seg6local.sh \
>  	test_lirc_mode2.sh \
> diff --git a/tools/testing/selftests/bpf/prog_tests/test_xdp_veth.c b/tools/testing/selftests/bpf/prog_tests/test_xdp_veth.c
> new file mode 100644
> index 000000000000..3ffeb411c131
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/prog_tests/test_xdp_veth.c
> @@ -0,0 +1,211 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/**
> + * Create 3 namespaces with 3 veth peers, and
> + * forward packets in-between using native XDP
> + *
> + *                      XDP_TX
> + * NS1(veth11)        NS2(veth22)        NS3(veth33)
> + *      |                  |                  |
> + *      |                  |                  |
> + *   (veth1,            (veth2,            (veth3,
> + *   id:111)            id:122)            id:133)
> + *     ^ |                ^ |                ^ |
> + *     | |  XDP_REDIRECT  | |  XDP_REDIRECT  | |
> + *     | ------------------ ------------------ |
> + *     -----------------------------------------
> + *                    XDP_REDIRECT
> + */

Hi Alexis,

A minor nit from my side.

The comment above starts with '/**' but otherwise it is not a Kernel doc.
It's probably best if it's a networking-style multi-line comment instead.

/* Create 3 namespaces with 3 veth peers, and
 * ...
 */

...