[PATCH bpf-next 3/3] selftests/bpf: Test skops->skb_hwtstamp

[Martin KaFai Lau <martin.lau@linux.dev>]

From: Martin KaFai Lau <martin.lau@kernel.org>

This patch tests reading the skops->skb_hwtstamp field.

A local test was also done such that the shinfo hwtstamp was temporary
set to a non zero value in the kernel bpf_skops_parse_hdr()
and the same value can be read by the skops test.

Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
---
 tools/testing/selftests/bpf/prog_tests/tcp_hdr_options.c      | 2 ++
 tools/testing/selftests/bpf/progs/test_misc_tcp_hdr_options.c | 4 ++++
 2 files changed, 6 insertions(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/tcp_hdr_options.c b/tools/testing/selftests/bpf/prog_tests/tcp_hdr_options.c
index 57191773572a..5cf85d0f9827 100644
--- a/tools/testing/selftests/bpf/prog_tests/tcp_hdr_options.c
+++ b/tools/testing/selftests/bpf/prog_tests/tcp_hdr_options.c
@@ -505,6 +505,8 @@ static void misc(void)
 
 	ASSERT_EQ(misc_skel->bss->nr_fin, 1, "unexpected nr_fin");
 
+	ASSERT_EQ(misc_skel->bss->nr_hwtstamp, 0, "nr_hwtstamp");
+
 check_linum:
 	ASSERT_FALSE(check_error_linum(&sk_fds), "check_error_linum");
 	sk_fds_close(&sk_fds);
diff --git a/tools/testing/selftests/bpf/progs/test_misc_tcp_hdr_options.c b/tools/testing/selftests/bpf/progs/test_misc_tcp_hdr_options.c
index 2c121c5d66a7..d487153a839d 100644
--- a/tools/testing/selftests/bpf/progs/test_misc_tcp_hdr_options.c
+++ b/tools/testing/selftests/bpf/progs/test_misc_tcp_hdr_options.c
@@ -27,6 +27,7 @@ unsigned int nr_pure_ack = 0;
 unsigned int nr_data = 0;
 unsigned int nr_syn = 0;
 unsigned int nr_fin = 0;
+unsigned int nr_hwtstamp = 0;
 
 /* Check the header received from the active side */
 static int __check_active_hdr_in(struct bpf_sock_ops *skops, bool check_syn)
@@ -146,6 +147,9 @@ static int check_active_hdr_in(struct bpf_sock_ops *skops)
 	if (th->ack && !th->fin && tcp_hdrlen(th) == skops->skb_len)
 		nr_pure_ack++;
 
+	if (skops->skb_hwtstamp)
+		nr_hwtstamp++;
+
 	return CG_OK;
 }
 
-- 
2.30.2