This patch tests the new helper bpf_mptcpify(). Store the new protocol
value after invoking the helper to a local BSS variable.

This is defined in a 'socket_create' SEC, so it will be hooked in the
newly added wrapper socket_create().

Signed-off-by: Geliang Tang <geliang.tang@suse.com>
---
 tools/testing/selftests/bpf/progs/mptcpify.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/progs/mptcpify.c

diff --git a/tools/testing/selftests/bpf/progs/mptcpify.c b/tools/testing/selftests/bpf/progs/mptcpify.c
new file mode 100644
index 000000000000..18078c1d351a
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/mptcpify.c
@@ -0,0 +1,16 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2023, SUSE. */
+
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include "bpf_tcp_helpers.h"
+
+char _license[] SEC("license") = "GPL";
+
+SEC("fentry/socket_create")
+int BPF_PROG(trace_socket_create, void *args,
+		struct socket **res)
+{
+	bpf_mptcpify(args);
+	return 0;
+}
-- 
2.35.3