Modify test_control_group to have toggle parameter.
When toggle is non-zero, loopback device will be set down for the
initialization of fd[1] which is still expected to successfully join
the fanout.

Signed-off-by: Gur Stavi <gur.stavi@huawei.com>
---
 tools/testing/selftests/net/psock_fanout.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/net/psock_fanout.c b/tools/testing/selftests/net/psock_fanout.c
index 64edcd661d43..49023d9b85b4 100644
--- a/tools/testing/selftests/net/psock_fanout.c
+++ b/tools/testing/selftests/net/psock_fanout.c
@@ -302,17 +302,22 @@ static void test_control_single(void)
 }
 
 /* Test illegal group with different modes or flags */
-static void test_control_group(void)
+static void test_control_group(int toggle)
 {
 	int fds[2];
 
-	fprintf(stderr, "test: control multiple sockets\n");
+	if (toggle)
+		fprintf(stderr, "test: control multiple sockets with link down toggle\n");
+	else
+		fprintf(stderr, "test: control multiple sockets\n");
 
 	fds[0] = sock_fanout_open(PACKET_FANOUT_HASH, 0);
 	if (fds[0] == -1) {
 		fprintf(stderr, "ERROR: failed to open HASH socket\n");
 		cleanup_and_exit(1);
 	}
+	if (toggle)
+		loopback_up_down_toggle();
 	if (sock_fanout_open(PACKET_FANOUT_HASH |
 			       PACKET_FANOUT_FLAG_DEFRAG, 0) != -1) {
 		fprintf(stderr, "ERROR: joined group with wrong flag defrag\n");
@@ -332,6 +337,7 @@ static void test_control_group(void)
 		fprintf(stderr, "ERROR: failed to join group\n");
 		cleanup_and_exit(1);
 	}
+	loopback_up_down_restore();
 	if (close(fds[1]) || close(fds[0])) {
 		fprintf(stderr, "ERROR: closing sockets\n");
 		cleanup_and_exit(1);
@@ -527,7 +533,8 @@ int main(int argc, char **argv)
 	int port_off = 2, tries = 20, ret;
 
 	test_control_single();
-	test_control_group();
+	test_control_group(0);
+	test_control_group(1);
 	test_control_group_max_num_members();
 	test_unique_fanout_group_ids();
 
-- 
2.45.2