This patch expended the MPTCP test base to support MPTCP packet
scheduler tests. Add the bpf_first MPTCP sched test in it. Use
sysctl to set net.mptcp.scheduler to use this sched.

Signed-off-by: Geliang Tang <geliang.tang@suse.com>
---
 .../testing/selftests/bpf/prog_tests/mptcp.c  | 42 +++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/mptcp.c b/tools/testing/selftests/bpf/prog_tests/mptcp.c
index b7c230c4efef..151350202fa6 100644
--- a/tools/testing/selftests/bpf/prog_tests/mptcp.c
+++ b/tools/testing/selftests/bpf/prog_tests/mptcp.c
@@ -4,6 +4,7 @@
 #include <test_progs.h>
 #include "cgroup_helpers.h"
 #include "network_helpers.h"
+#include "bpf_first.skel.h"
 
 #ifndef TCP_CA_NAME_MAX
 #define TCP_CA_NAME_MAX	16
@@ -19,6 +20,15 @@ struct mptcp_storage {
 };
 
 static char monitor_log_path[64];
+static int duration;
+
+static void send_byte(int fd)
+{
+	char b = 0x55;
+
+	if (CHECK_FAIL(write(fd, &b, sizeof(b)) != 1))
+		perror("Failed to send single byte");
+}
 
 static int verify_tsk(int map_fd, int client_fd)
 {
@@ -202,6 +212,8 @@ static int run_test(int cgroup_fd, int server_fd, bool is_mptcp)
 		goto close_client_fd;
 	}
 
+	send_byte(client_fd);
+
 	err += is_mptcp ? verify_msk(map_fd, client_fd) :
 			  verify_tsk(map_fd, client_fd);
 
@@ -254,8 +266,38 @@ void test_base(void)
 	close(cgroup_fd);
 }
 
+static void test_first(void)
+{
+	struct bpf_first *first_skel;
+	int server_fd, client_fd;
+	struct bpf_link *link;
+
+	first_skel = bpf_first__open_and_load();
+	if (CHECK(!first_skel, "bpf_first__open_and_load", "failed\n"))
+		return;
+
+	link = bpf_map__attach_struct_ops(first_skel->maps.first);
+	if (!ASSERT_OK_PTR(link, "bpf_map__attach_struct_ops")) {
+		bpf_first__destroy(first_skel);
+		return;
+	}
+
+	system("sysctl -q net.mptcp.scheduler=bpf_first");
+	server_fd = start_mptcp_server(AF_INET, NULL, 0, 0);
+	client_fd = connect_to_mptcp_fd(server_fd, 0);
+
+	send_byte(client_fd);
+
+	close(client_fd);
+	close(server_fd);
+	bpf_link__destroy(link);
+	bpf_first__destroy(first_skel);
+}
+
 void test_mptcp(void)
 {
 	if (test__start_subtest("base"))
 		test_base();
+	if (test__start_subtest("first"))
+		test_first();
 }
-- 
2.34.1