diff --git a/tools/testing/selftests/net/forwarding/lib.sh b/tools/testing/selftests/net/forwarding/lib.sh
index 10cdfc0adca835497e7ce0f78f7cf93370c9422b..096340f064dbc1bf58fcfa9d3d73d9da793202fe 100644
--- a/tools/testing/selftests/net/forwarding/lib.sh
+++ b/tools/testing/selftests/net/forwarding/lib.sh
@@ -248,6 +248,24 @@ busywait()
 	done
 }
 
+until_counter_is()
+{
+	local value=$1; shift
+	local current=$("$@")
+
+	echo $((current))
+	((current >= value))
+}
+
+busywait_for_counter()
+{
+	local timeout=$1; shift
+	local delta=$1; shift
+
+	local base=$("$@")
+	busywait "$timeout" until_counter_is $((base + delta)) "$@"
+}
+
 setup_wait_dev()
 {
 	local dev=$1; shift