selftests: forwarding: Introduce $ARPING

Instead of relying on "arping" being installed everywhere under that
name, introduce a variable $ARPING like the other tools do.

Convert an existing test, mirror_gre_vlan_bridge_1q.sh to
require_command $ARPING and then invoke arping through the variable.
Signed-off-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tools/testing/selftests/net/forwarding/lib.sh

@@ -8,6 +8,7 @@
 PING=${PING:=ping}
 PING6=${PING6:=ping6}
 MZ=${MZ:=mausezahn}
+ARPING=${ARPING:=arping}
 TEAMD=${TEAMD:=teamd}
 WAIT_TIME=${WAIT_TIME:=5}
 PAUSE_ON_FAIL=${PAUSE_ON_FAIL:=no}

tools/testing/selftests/net/forwarding/mirror_gre_vlan_bridge_1q.sh

@@ -28,6 +28,8 @@ source mirror_lib.sh
 source mirror_gre_lib.sh
 source mirror_gre_topo_lib.sh
 
+require_command $ARPING
+
 setup_prepare()
 {
 	h1=${NETIFS[p1]}
@@ -149,7 +151,7 @@ test_span_gre_forbidden_egress()
 
 	bridge vlan add dev $swp3 vid 555
 	# Re-prime FDB
-	arping -I br1.555 192.0.2.130 -fqc 1
+	$ARPING -I br1.555 192.0.2.130 -fqc 1
 	sleep 1
 	quick_test_span_gre_dir $tundev ingress
 
@@ -223,7 +225,7 @@ test_span_gre_fdb_roaming()
 
 	bridge fdb del dev $swp2 $h3mac vlan 555 master
 	# Re-prime FDB
-	arping -I br1.555 192.0.2.130 -fqc 1
+	$ARPING -I br1.555 192.0.2.130 -fqc 1
 	sleep 1
 	quick_test_span_gre_dir $tundev ingress