Re: [PATCH bpf-next 6/6] selftests: bpf: test sockmap update from BPF

From: Yonghong Song
Date: Thu Aug 20 2020 - 10:50:06 EST




On 8/20/20 4:58 AM, Lorenz Bauer wrote:
On Wed, 19 Aug 2020 at 21:46, Yonghong Song <yhs@xxxxxx> wrote:



On 8/19/20 2:24 AM, Lorenz Bauer wrote:
Add a test which copies a socket from a sockmap into another sockmap
or sockhash. This excercises bpf_map_update_elem support from BPF
context. Compare the socket cookies from source and destination to
ensure that the copy succeeded.

Signed-off-by: Lorenz Bauer <lmb@xxxxxxxxxxxxxx>
---
.../selftests/bpf/prog_tests/sockmap_basic.c | 76 +++++++++++++++++++
.../selftests/bpf/progs/test_sockmap_copy.c | 48 ++++++++++++
2 files changed, 124 insertions(+)
create mode 100644 tools/testing/selftests/bpf/progs/test_sockmap_copy.c

diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c b/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c
index 96e7b7f84c65..d30cabc00e9e 100644
--- a/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c
+++ b/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c
@@ -4,6 +4,7 @@

#include "test_progs.h"
#include "test_skmsg_load_helpers.skel.h"
+#include "test_sockmap_copy.skel.h"

#define TCP_REPAIR 19 /* TCP sock is under repair right now */

@@ -101,6 +102,77 @@ static void test_skmsg_helpers(enum bpf_map_type map_type)
test_skmsg_load_helpers__destroy(skel);
}

+static void test_sockmap_copy(enum bpf_map_type map_type)
+{
+ struct bpf_prog_test_run_attr attr;
+ struct test_sockmap_copy *skel;
+ __u64 src_cookie, dst_cookie;
+ int err, prog, s, src, dst;
+ const __u32 zero = 0;
+ char dummy[14] = {0};
+
+ s = connected_socket_v4();

Maybe change variable name to "sk" for better clarity?

Yup!


+ if (CHECK_FAIL(s == -1))
+ return;
+
+ skel = test_sockmap_copy__open_and_load();
+ if (CHECK_FAIL(!skel)) {
+ close(s);
+ perror("test_sockmap_copy__open_and_load");
+ return;
+ }

Could you use CHECK instead of CHECK_FAIL?
With CHECK, you can print additional information without perror.

I avoid CHECK because it requires `duration`, which doesn't make sense
for most things that I call CHECK_FAIL on here. So either it outputs 0
nsec (which is bogus) or it outputs the value from the last
bpf_prog_test_run call (which is also bogus). How do other tests
handle this? Just ignore it?

Just ignore it. You can define a static variable duration in the beginning of file and then use CHECK in the rest of file.




+
+ prog = bpf_program__fd(skel->progs.copy_sock_map);
+ src = bpf_map__fd(skel->maps.src);
+ if (map_type == BPF_MAP_TYPE_SOCKMAP)
+ dst = bpf_map__fd(skel->maps.dst_sock_map);
+ else
+ dst = bpf_map__fd(skel->maps.dst_sock_hash);
+
[...]