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

[Kumar Kartikeya Dwivedi <memxor@gmail.com>]

On Sat, May 01, 2021 at 01:11:47AM IST, Andrii Nakryiko wrote:
> 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
>

Ok.

> > +       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?
>

Yes, thanks for spotting it.

> > +
> > +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)
>

I agree it looks bad. I can also just make a new opts for each combination, and
name it that way. Maybe that will look much better.

> > +       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
>

Ok, will fix everywhere.

> > +               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;
> > +}
> > +
>
> [...]

--
Kartikeya