[PATCH bpf-next v3 6/6] bpf: Test bpf_sk_storage_get in tcp iterators

[Florent Revest]

This extends the existing bpf_sk_storage_get test where a socket is
created and tagged with its creator's pid by a task_file iterator.

A TCP iterator is now also used at the end of the test to negate the
values already stored in the local storage. The test therefore expects
-getpid() to be stored in the local storage.

Signed-off-by: Florent Revest <rev...@google.com>
---
 .../selftests/bpf/prog_tests/bpf_iter.c        | 13 +++++++++++++
 .../progs/bpf_iter_bpf_sk_storage_helpers.c    | 18 ++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_iter.c 
b/tools/testing/selftests/bpf/prog_tests/bpf_iter.c
index 9336d0f18331..b8362147c9e3 100644
--- a/tools/testing/selftests/bpf/prog_tests/bpf_iter.c
+++ b/tools/testing/selftests/bpf/prog_tests/bpf_iter.c
@@ -978,6 +978,8 @@ static void test_bpf_sk_storage_delete(void)
 /* This creates a socket and its local storage. It then runs a task_iter BPF
  * program that replaces the existing socket local storage with the tgid of the
  * only task owning a file descriptor to this socket, this process, prog_tests.
+ * It then runs a tcp socket iterator that negates the value in the existing
+ * socket local storage, the test verifies that the resulting value is -pid.
  */
 static void test_bpf_sk_storage_get(void)
 {
@@ -994,6 +996,10 @@ static void test_bpf_sk_storage_get(void)
        if (CHECK(sock_fd < 0, "socket", "errno: %d\n", errno))
                goto out;
 
+       err = listen(sock_fd, 1);
+       if (CHECK(err != 0, "listen", "errno: %d\n", errno))
+               goto out;
+
        map_fd = bpf_map__fd(skel->maps.sk_stg_map);
 
        err = bpf_map_update_elem(map_fd, &sock_fd, &val, BPF_NOEXIST);
@@ -1007,6 +1013,13 @@ static void test_bpf_sk_storage_get(void)
              "map value wasn't set correctly (expected %d, got %d, err=%d)\n",
              getpid(), val, err);
 
+       do_dummy_read(skel->progs.negate_socket_local_storage);
+
+       err = bpf_map_lookup_elem(map_fd, &sock_fd, &val);
+       CHECK(err || val != -getpid(), "bpf_map_lookup_elem",
+             "map value wasn't set correctly (expected %d, got %d, err=%d)\n",
+             -getpid(), val, err);
+
 close_socket:
        close(sock_fd);
 out:
diff --git 
a/tools/testing/selftests/bpf/progs/bpf_iter_bpf_sk_storage_helpers.c 
b/tools/testing/selftests/bpf/progs/bpf_iter_bpf_sk_storage_helpers.c
index d7a7a802d172..b3f0cb139c55 100644
--- a/tools/testing/selftests/bpf/progs/bpf_iter_bpf_sk_storage_helpers.c
+++ b/tools/testing/selftests/bpf/progs/bpf_iter_bpf_sk_storage_helpers.c
@@ -46,3 +46,21 @@ int fill_socket_owner(struct bpf_iter__task_file *ctx)
        return 0;
 }
 
+SEC("iter/tcp")
+int negate_socket_local_storage(struct bpf_iter__tcp *ctx)
+{
+       struct sock_common *sk_common = ctx->sk_common;
+       int *sock_tgid;
+
+       if (!sk_common)
+               return 0;
+
+       sock_tgid = bpf_sk_storage_get(&sk_stg_map, sk_common, 0, 0);
+       if (!sock_tgid)
+               return 0;
+
+       *sock_tgid = -*sock_tgid;
+
+       return 0;
+}
+
-- 
2.29.2.454.gaff20da3a2-goog