selftests: mptcp: add mptcp_lib_get_counter

To avoid duplicated code in different MPTCP selftests, we can add
and use helpers defined in mptcp_lib.sh.

The helper get_counter() in mptcp_join.sh and get_mib_counter() in
mptcp_connect.sh have the same functionality, export get_counter() into
mptcp_lib.sh and rename it as mptcp_lib_get_counter(). Use this new
helper instead of get_counter() and get_mib_counter().

Use this helper in test_prio() in userspace_pm.sh too instead of
open-coding.

Reviewed-by: Matthieu Baerts <matttbe@kernel.org>
Signed-off-by: Geliang Tang <geliang.tang@suse.com>
Signed-off-by: Mat Martineau <martineau@kernel.org>
Link: https://lore.kernel.org/r/20231128-send-net-next-2023107-v4-11-8d6b94150f6b@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 16 insertions, 0 deletions

diff --git a/tools/testing/selftests/net/mptcp/mptcp_lib.sh b/tools/testing/selftests/net/mptcp/mptcp_lib.sh
index 447292cad33c..718c79dda2b3 100644
--- a/tools/testing/selftests/net/mptcp/mptcp_lib.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_lib.sh
@@ -231,3 +231,19 @@ mptcp_lib_kill_wait() {
 mptcp_lib_is_v6() {
 	[ -z "${1##*:*}" ]
 }
+
+# $1: ns, $2: MIB counter
+mptcp_lib_get_counter() {
+	local ns="${1}"
+	local counter="${2}"
+	local count
+
+	count=$(ip netns exec "${ns}" nstat -asz "${counter}" |
+		awk 'NR==1 {next} {print $2}')
+	if [ -z "${count}" ]; then
+		mptcp_lib_fail_if_expected_feature "${counter} counter"
+		return 1
+	fi
+
+	echo "${count}"
+}