netdev - Re: [bpf-next PATCH v5 4/5] bpf, selftests: add sk

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Date:   Tue, 26 May 2020 11:07:35 -0700
From:   Andrii Nakryiko <andrii.nakryiko@...il.com>
To:     John Fastabend <john.fastabend@...il.com>
Cc:     Yonghong Song <yhs@...com>, Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Networking <netdev@...r.kernel.org>, bpf <bpf@...r.kernel.org>
Subject: Re: [bpf-next PATCH v5 4/5] bpf, selftests: add sk_msg helpers load
 and attach test

On Sun, May 24, 2020 at 9:51 AM John Fastabend <john.fastabend@...il.com> wrote:
>
> The test itself is not particularly useful but it encodes a common
> pattern we have.
>
> Namely do a sk storage lookup then depending on data here decide if
> we need to do more work or alternatively allow packet to PASS. Then
> if we need to do more work consult task_struct for more information
> about the running task. Finally based on this additional information
> drop or pass the data. In this case the suspicious check is not so
> realisitic but it encodes the general pattern and uses the helpers
> so we test the workflow.
>
> This is a load test to ensure verifier correctly handles this case.
>
> Signed-off-by: John Fastabend <john.fastabend@...il.com>
> ---

Other than perror and CHECK_FAIL nag below, looks good:

Acked-by: Andrii Nakryiko <andriin@...com>

>  .../selftests/bpf/prog_tests/sockmap_basic.c       |   35 +++++++++++++++
>  .../selftests/bpf/progs/test_skmsg_load_helpers.c  |   47 ++++++++++++++++++++
>  2 files changed, 82 insertions(+)
>  create mode 100644 tools/testing/selftests/bpf/progs/test_skmsg_load_helpers.c
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c b/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c
> index aa43e0b..96e7b7f 100644
> --- a/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c
> +++ b/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c
> @@ -1,7 +1,9 @@
>  // SPDX-License-Identifier: GPL-2.0
>  // Copyright (c) 2020 Cloudflare
> +#include <error.h>
>
>  #include "test_progs.h"
> +#include "test_skmsg_load_helpers.skel.h"
>
>  #define TCP_REPAIR             19      /* TCP sock is under repair right now */
>
> @@ -70,10 +72,43 @@ static void test_sockmap_create_update_free(enum bpf_map_type map_type)
>         close(s);
>  }
>
> +static void test_skmsg_helpers(enum bpf_map_type map_type)
> +{
> +       struct test_skmsg_load_helpers *skel;
> +       int err, map, verdict;
> +
> +       skel = test_skmsg_load_helpers__open_and_load();
> +       if (CHECK_FAIL(!skel)) {
> +               perror("test_skmsg_load_helpers__open_and_load");

All test_progs tests use CHECK() macro to test and emit error message
on error, so no need to do silent CHECK_FAIL() and then perror(). Same
below in few places. I don't think you need to send v6 just for this,
but please follow up with a clean up.

> +               return;
> +       }
> +
> +       verdict = bpf_program__fd(skel->progs.prog_msg_verdict);
> +       map = bpf_map__fd(skel->maps.sock_map);
> +
> +       err = bpf_prog_attach(verdict, map, BPF_SK_MSG_VERDICT, 0);
> +       if (CHECK_FAIL(err)) {
> +               perror("bpf_prog_attach");
> +               goto out;
> +       }
> +
> +       err = bpf_prog_detach2(verdict, map, BPF_SK_MSG_VERDICT);
> +       if (CHECK_FAIL(err)) {
> +               perror("bpf_prog_detach2");
> +               goto out;
> +       }
> +out:
> +       test_skmsg_load_helpers__destroy(skel);
> +}
> +

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