Re: [PATCH bpf-next v2 09/13] selftests/bpf: move ip checksum helper to network helpers

From: Stanislav Fomichev
Date: Fri Nov 15 2024 - 10:39:29 EST


On 11/14, Alexis Lothoré (eBPF Foundation) wrote:
> xdp_metadata test has a small helper computing ipv checksums to allow
> manually building packets.
>
> Move this helper to network_helpers to share it with other tests.
>
> Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore@xxxxxxxxxxx>
> ---
> Changes in v2:
> - new patch
> ---
> tools/testing/selftests/bpf/network_helpers.h | 23 ++++++++++++++++++++++
> .../selftests/bpf/prog_tests/xdp_metadata.c | 19 +-----------------
> 2 files changed, 24 insertions(+), 18 deletions(-)
>
> diff --git a/tools/testing/selftests/bpf/network_helpers.h b/tools/testing/selftests/bpf/network_helpers.h
> index c72c16e1aff825439896b38e59962ffafe92dc71..c9b72960c651ab9fb249f6eb9e153b8416b7a488 100644
> --- a/tools/testing/selftests/bpf/network_helpers.h
> +++ b/tools/testing/selftests/bpf/network_helpers.h
> @@ -104,6 +104,29 @@ static __u16 csum_fold(__u32 csum)
> return (__u16)~csum;
> }
>

[..]

> +static unsigned long add_csum_hword(const __u16 *start, int num_u16)
> +{
> + unsigned long sum = 0;
> + int i;
> +
> + for (i = 0; i < num_u16; i++)
> + sum += start[i];
> +
> + return sum;
> +}

Sorry for nitpicking, but can we call it csum_partial? And match
kernel's prototype with extra sum argument? Should be more greppable
for the future test cases that might want to use it...