[PATCH bpf-next v2 3/3] selftests/bpf: Improve test tcpbpf_user robustness

[Mathieu Jadin <mathjadin@xxxxxxxxx>]

Allow the test to support any number of supported callback flags.
Provided that BPF_SOCK_OPS_ALL_CB_FLAGS is correctly updated when new
flags are added, left shifting it always leads to a non existing flag.

Signed-off-by: Mathieu Jadin <mathjadin@xxxxxxxxx>
---
 tools/testing/selftests/bpf/prog_tests/tcpbpf_user.c | 4 +++-
 tools/testing/selftests/bpf/progs/test_tcpbpf_kern.c | 9 +++++++--
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/tcpbpf_user.c b/tools/testing/selftests/bpf/prog_tests/tcpbpf_user.c
index 87923d2865b7..56d007bf4011 100644
--- a/tools/testing/selftests/bpf/prog_tests/tcpbpf_user.c
+++ b/tools/testing/selftests/bpf/prog_tests/tcpbpf_user.c
@@ -12,6 +12,8 @@ static __u32 duration;
 
 static void verify_result(struct tcpbpf_globals *result)
 {
+	__u32 non_existing_flag = (BPF_SOCK_OPS_ALL_CB_FLAGS << 1) &
+				  ~BPF_SOCK_OPS_ALL_CB_FLAGS;
 	__u32 expected_events = ((1 << BPF_SOCK_OPS_TIMEOUT_INIT) |
 				 (1 << BPF_SOCK_OPS_RWND_INIT) |
 				 (1 << BPF_SOCK_OPS_TCP_CONNECT_CB) |
@@ -30,7 +32,7 @@ static void verify_result(struct tcpbpf_globals *result)
 	ASSERT_EQ(result->bytes_acked, 1002, "bytes_acked");
 	ASSERT_EQ(result->data_segs_in, 1, "data_segs_in");
 	ASSERT_EQ(result->data_segs_out, 1, "data_segs_out");
-	ASSERT_EQ(result->bad_cb_test_rv, 0x80, "bad_cb_test_rv");
+	ASSERT_EQ(result->bad_cb_test_rv, non_existing_flag, "bad_cb_test_rv");
 	ASSERT_EQ(result->good_cb_test_rv, 0, "good_cb_test_rv");
 	ASSERT_EQ(result->num_listen, 1, "num_listen");
 
diff --git a/tools/testing/selftests/bpf/progs/test_tcpbpf_kern.c b/tools/testing/selftests/bpf/progs/test_tcpbpf_kern.c
index 3ded05280757..c37ba5940e3d 100644
--- a/tools/testing/selftests/bpf/progs/test_tcpbpf_kern.c
+++ b/tools/testing/selftests/bpf/progs/test_tcpbpf_kern.c
@@ -43,6 +43,8 @@ SEC("sockops")
 int bpf_testcb(struct bpf_sock_ops *skops)
 {
 	char header[sizeof(struct ipv6hdr) + sizeof(struct tcphdr)];
+	__u32 non_existing_flag = (BPF_SOCK_OPS_ALL_CB_FLAGS << 1) &
+				  ~BPF_SOCK_OPS_ALL_CB_FLAGS;
 	struct bpf_sock_ops *reuse = skops;
 	struct tcphdr *thdr;
 	int window_clamp = 9216;
@@ -104,8 +106,11 @@ int bpf_testcb(struct bpf_sock_ops *skops)
 		global.window_clamp_client = get_tp_window_clamp(skops);
 		break;
 	case BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB:
-		/* Test failure to set largest cb flag (assumes not defined) */
-		global.bad_cb_test_rv = bpf_sock_ops_cb_flags_set(skops, 0x80);
+		/* Test failure to set largest cb flag
+		 * (assumes that BPF_SOCK_OPS_ALL_CB_FLAGS masks all cb flags)
+		 */
+		global.bad_cb_test_rv = bpf_sock_ops_cb_flags_set(skops,
+							  non_existing_flag);
 		/* Set callback */
 		global.good_cb_test_rv = bpf_sock_ops_cb_flags_set(skops,
 						 BPF_SOCK_OPS_STATE_CB_FLAG);
-- 
2.32.0