Re: [PATCH bpf-next v5 3/3] libbpf: add selftests for TC-BPF API

[Andrii Nakryiko <andrii.nakryiko@gmail.com>]

On Wed, Apr 28, 2021 at 9:26 AM Kumar Kartikeya Dwivedi
<memxor@gmail.com> wrote:
>
> This adds some basic tests for the low level bpf_tc_* API.
>
> Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
> Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
> ---
>  .../testing/selftests/bpf/prog_tests/tc_bpf.c | 467 ++++++++++++++++++
>  .../testing/selftests/bpf/progs/test_tc_bpf.c |  12 +
>  2 files changed, 479 insertions(+)
>  create mode 100644 tools/testing/selftests/bpf/prog_tests/tc_bpf.c
>  create mode 100644 tools/testing/selftests/bpf/progs/test_tc_bpf.c
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/tc_bpf.c b/tools/testing/selftests/bpf/prog_tests/tc_bpf.c
> new file mode 100644
> index 000000000000..40441f4e23e2
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/prog_tests/tc_bpf.c
> @@ -0,0 +1,467 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include <test_progs.h>
> +#include <linux/pkt_cls.h>
> +
> +#include "test_tc_bpf.skel.h"
> +
> +#define LO_IFINDEX 1
> +
> +static int test_tc_internal(const struct bpf_tc_hook *hook, int fd)
> +{
> +       DECLARE_LIBBPF_OPTS(bpf_tc_opts, opts, .handle = 1, .priority = 1,
> +                           .prog_fd = fd);

we have 100 characters, if needed, use it to keep it on the single line

> +       struct bpf_prog_info info = {};
> +       int ret;
> +
> +       ret = bpf_obj_get_info_by_fd(fd, &info, &(__u32){sizeof(info)});

as in previous patch, don't do this

> +       if (!ASSERT_OK(ret, "bpf_obj_get_info_by_fd"))
> +               return ret;
> +
> +       ret = bpf_tc_attach(hook, &opts, 0);
> +       if (!ASSERT_OK(ret, "bpf_tc_attach"))
> +               return ret;
> +
> +       if (!ASSERT_EQ(opts.handle, 1, "handle set") ||
> +           !ASSERT_EQ(opts.priority, 1, "priority set") ||
> +           !ASSERT_EQ(opts.prog_id, info.id, "prog_id set"))
> +               goto end;
> +
> +       DECLARE_LIBBPF_OPTS(bpf_tc_opts, info_opts, .prog_fd = fd);

this is not C89, please move variable declarations to the top

> +       ret = bpf_tc_query(hook, &info_opts);
> +       if (!ASSERT_OK(ret, "bpf_tc_query"))
> +               goto end;
> +
> +       DECLARE_LIBBPF_OPTS(bpf_tc_opts, info_opts2, .prog_id = info.id);

and here

> +       ret = bpf_tc_query(hook, &info_opts2);
> +       if (!ASSERT_OK(ret, "bpf_tc_query"))
> +               goto end;
> +
> +       if (!ASSERT_EQ(opts.handle, 1, "handle set") ||
> +           !ASSERT_EQ(opts.priority, 1, "priority set") ||
> +           !ASSERT_EQ(opts.prog_id, info.id, "prog_id set"))
> +               goto end;
> +
> +       opts.prog_id = 0;
> +       ret = bpf_tc_attach(hook, &opts, BPF_TC_F_REPLACE);
> +       if (!ASSERT_OK(ret, "bpf_tc_attach replace mode"))
> +               return ret;

goto end?

> +
> +end:
> +       opts.prog_fd = opts.prog_id = 0;
> +       ret = bpf_tc_detach(hook, &opts);
> +       ASSERT_OK(ret, "bpf_tc_detach");
> +       return ret;
> +}
> +

[...]

> +
> +       /* attach */
> +       ret = bpf_tc_attach(NULL, &attach_opts, 0);
> +       if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_attach invalid hook = NULL"))
> +               return -EINVAL;
> +       ret = bpf_tc_attach(hook, &attach_opts, 42);
> +       if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_attach invalid flags"))
> +               return -EINVAL;
> +       attach_opts.prog_fd = 0;
> +       ret = bpf_tc_attach(hook, &attach_opts, 0);
> +       if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_attach invalid prog_fd unset"))
> +               return -EINVAL;
> +       attach_opts.prog_fd = fd;
> +       attach_opts.prog_id = 42;
> +       ret = bpf_tc_attach(hook, &attach_opts, 0);
> +       if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_attach invalid prog_id set"))
> +               return -EINVAL;
> +       attach_opts.prog_id = 0;
> +       attach_opts.handle = 0;
> +       ret = bpf_tc_attach(hook, &attach_opts, 0);
> +       if (!ASSERT_OK(ret, "bpf_tc_attach valid handle unset"))
> +               return -EINVAL;
> +       attach_opts.prog_fd = attach_opts.prog_id = 0;
> +       ASSERT_OK(bpf_tc_detach(hook, &attach_opts), "bpf_tc_detach");

this code is quite hard to follow, maybe sprinkle empty lines between
logical groups of statements (i.e., prepare inputs + call bpf_tc_xxx +
assert is one group that goes together)

> +       attach_opts.prog_fd = fd;
> +       attach_opts.handle = 1;
> +       attach_opts.priority = 0;
> +       ret = bpf_tc_attach(hook, &attach_opts, 0);
> +       if (!ASSERT_OK(ret, "bpf_tc_attach valid priority unset"))
> +               return -EINVAL;
> +       attach_opts.prog_fd = attach_opts.prog_id = 0;
> +       ASSERT_OK(bpf_tc_detach(hook, &attach_opts), "bpf_tc_detach");
> +       attach_opts.prog_fd = fd;
> +       attach_opts.priority = UINT16_MAX + 1;
> +       ret = bpf_tc_attach(hook, &attach_opts, 0);
> +       if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_attach invalid priority > UINT16_MAX"))
> +               return -EINVAL;
> +       attach_opts.priority = 0;
> +       attach_opts.handle = attach_opts.priority = 0;
> +       ret = bpf_tc_attach(hook, &attach_opts, 0);
> +       if (!ASSERT_OK(ret, "bpf_tc_attach valid both handle and priority unset"))
> +               return -EINVAL;
> +       attach_opts.prog_fd = attach_opts.prog_id = 0;
> +       ASSERT_OK(bpf_tc_detach(hook, &attach_opts), "bpf_tc_detach");
> +       ret = bpf_tc_attach(hook, NULL, 0);
> +       if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_attach invalid opts = NULL"))
> +               return -EINVAL;
> +
> +       return 0;
> +}
> +
> +static int test_tc_query(const struct bpf_tc_hook *hook, int fd)
> +{
> +       struct test_tc_bpf *skel = NULL;
> +       int new_fd, ret, i = 0;
> +
> +       skel = test_tc_bpf__open_and_load();
> +       if (!ASSERT_OK_PTR(skel, "test_tc_bpf__open_and_load"))
> +               return -EINVAL;
> +
> +       new_fd = bpf_program__fd(skel->progs.cls);
> +
> +       /* make sure no other filters are attached */
> +       ret = bpf_tc_query(hook, NULL);
> +       if (!ASSERT_EQ(ret, -ENOENT, "bpf_tc_query == -ENOENT"))
> +               goto end_destroy;
> +
> +       for (i = 0; i < 5; i++) {
> +               DECLARE_LIBBPF_OPTS(bpf_tc_opts, opts, .prog_fd = fd);

empty line after variable declaration

> +               ret = bpf_tc_attach(hook, &opts, 0);
> +               if (!ASSERT_OK(ret, "bpf_tc_attach"))
> +                       goto end;
> +       }
> +       DECLARE_LIBBPF_OPTS(bpf_tc_opts, opts, .handle = 1, .priority = 1,
> +                           .prog_fd = new_fd);
> +       ret = bpf_tc_attach(hook, &opts, 0);
> +       if (!ASSERT_OK(ret, "bpf_tc_attach"))
> +               goto end;
> +       i++;
> +
> +       ASSERT_EQ(opts.handle, 1, "handle match");
> +       ASSERT_EQ(opts.priority, 1, "priority match");
> +       ASSERT_NEQ(opts.prog_id, 0, "prog_id set");
> +
> +       opts.prog_fd = 0;
> +       /* search with handle, priority, prog_id */
> +       ret = bpf_tc_query(hook, &opts);
> +       if (!ASSERT_OK(ret, "bpf_tc_query"))
> +               goto end;
> +
> +       ASSERT_EQ(opts.handle, 1, "handle match");
> +       ASSERT_EQ(opts.priority, 1, "priority match");
> +       ASSERT_NEQ(opts.prog_id, 0, "prog_id set");
> +
> +       opts.priority = opts.prog_fd = 0;
> +       /* search with handle, prog_id */
> +       ret = bpf_tc_query(hook, &opts);
> +       if (!ASSERT_OK(ret, "bpf_tc_query"))
> +               goto end;
> +
> +       ASSERT_EQ(opts.handle, 1, "handle match");
> +       ASSERT_EQ(opts.priority, 1, "priority match");
> +       ASSERT_NEQ(opts.prog_id, 0, "prog_id set");
> +
> +       opts.handle = opts.prog_fd = 0;
> +       /* search with priority, prog_id */
> +       ret = bpf_tc_query(hook, &opts);
> +       if (!ASSERT_OK(ret, "bpf_tc_query"))
> +               goto end;
> +
> +       ASSERT_EQ(opts.handle, 1, "handle match");
> +       ASSERT_EQ(opts.priority, 1, "priority match");
> +       ASSERT_NEQ(opts.prog_id, 0, "prog_id set");
> +
> +       opts.handle = opts.priority = opts.prog_fd = 0;
> +       /* search with prog_id */
> +       ret = bpf_tc_query(hook, &opts);
> +       if (!ASSERT_OK(ret, "bpf_tc_query"))
> +               goto end;
> +
> +       ASSERT_EQ(opts.handle, 1, "handle match");
> +       ASSERT_EQ(opts.priority, 1, "priority match");
> +       ASSERT_NEQ(opts.prog_id, 0, "prog_id set");
> +
> +       while (i != 1) {
> +               DECLARE_LIBBPF_OPTS(bpf_tc_opts, del_opts, .prog_fd = fd);

empty line here

> +               ret = bpf_tc_query(hook, &del_opts);
> +               if (!ASSERT_OK(ret, "bpf_tc_query"))
> +                       goto end;
> +               ASSERT_NEQ(del_opts.prog_id, opts.prog_id, "prog_id should not be same");
> +               ASSERT_NEQ(del_opts.priority, 1, "priority should not be 1");
> +               del_opts.prog_fd = del_opts.prog_id = 0;
> +               ret = bpf_tc_detach(hook, &del_opts);
> +               if (!ASSERT_OK(ret, "bpf_tc_detach"))
> +                       goto end;
> +               i--;
> +       }
> +
> +       opts.handle = opts.priority = opts.prog_id = 0;
> +       opts.prog_fd = fd;
> +       ret = bpf_tc_query(hook, &opts);
> +       ASSERT_EQ(ret, -ENOENT, "bpf_tc_query == -ENOENT");
> +
> +end:
> +       while (i--) {
> +               DECLARE_LIBBPF_OPTS(bpf_tc_opts, del_opts, 0);

you get the idea by now

> +               ret = bpf_tc_query(hook, &del_opts);
> +               if (!ASSERT_OK(ret, "bpf_tc_query"))
> +                       break;
> +               del_opts.prog_id = 0;
> +               ret = bpf_tc_detach(hook, &del_opts);
> +               if (!ASSERT_OK(ret, "bpf_tc_detach"))
> +                       break;
> +       }
> +       ASSERT_EQ(bpf_tc_query(hook, NULL), -ENOENT, "bpf_tc_query == -ENOENT");
> +end_destroy:
> +       test_tc_bpf__destroy(skel);
> +       return ret;
> +}
> +

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