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From:   Florent Revest <revest@chromium.org>
To:     bpf@vger.kernel.org
Cc:     viro@zeniv.linux.org.uk, davem@davemloft.net, kuba@kernel.org,
        ast@kernel.org, daniel@iogearbox.net, kafai@fb.com, yhs@fb.com,
        andrii@kernel.org, kpsingh@chromium.org, revest@google.com,
        linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Subject: [PATCH bpf-next v3 6/6] bpf: Test bpf_sk_storage_get in tcp iterators
Date:   Thu, 26 Nov 2020 17:44:49 +0100
Message-Id: <20201126164449.1745292-6-revest@google.com>
In-Reply-To: <20201126164449.1745292-1-revest@google.com>
References: <20201126164449.1745292-1-revest@google.com>
MIME-Version: 1.0
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Precedence: bulk

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 <revest@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