selftests: forwarding: lib: Move here vlan_capture_{, un}install()

Move vlan_capture_install() and vlan_capture_uninstall() from
mirror_vlan.sh test to lib.sh so that it can be reused in other tests.

Signed-off-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/tools/testing/selftests/net/forwarding/lib.sh b/tools/testing/selftests/net/forwarding/lib.sh
index 89ba4cd..7b18a53 100644
--- a/tools/testing/selftests/net/forwarding/lib.sh
+++ b/tools/testing/selftests/net/forwarding/lib.sh
@@ -514,6 +514,29 @@
 	__icmp_capture_add_del del 100 v6 "$@"
 }
 
+__vlan_capture_add_del()
+{
+	local add_del=$1; shift
+	local pref=$1; shift
+	local dev=$1; shift
+	local filter=$1; shift
+
+	tc filter $add_del dev "$dev" ingress \
+	   proto 802.1q pref $pref \
+	   flower $filter \
+	   action pass
+}
+
+vlan_capture_install()
+{
+	__vlan_capture_add_del add 100 "$@"
+}
+
+vlan_capture_uninstall()
+{
+	__vlan_capture_add_del del 100 "$@"
+}
+
 matchall_sink_create()
 {
 	local dev=$1; shift