traffic-control: Obey $NET_INTERFACE in traffic-control-tcdemo test

Don’t hard-code the traffic controlled interface to eth0, or the
traffic-control-tcdemo test will fail on devices where eth0 is not the
main network interface.

Bug: https://bugs.apertis.org/show_bug.cgi?id=328
Differential Revision: https://phabricator.apertis.org/D431


Signed-off-by: Philip Withnall <philip.withnall@collabora.co.uk>
Reviewed-by: Sjoerd Simons <sjoerd.simons@collabora.co.uk>

traffic-control/manual/run-tcdemo-test.sh

@@ -31,7 +31,7 @@ test_tcdemo() {
     local ret server_pid port="9000"
 
     ## Setup ##
-    sudo $TCMMD --save-stats=$TCMMD_LOG.$tc.$background -i eth0 >> $TCMMD_LOG 2>&1 &
+    sudo $TCMMD --save-stats=$TCMMD_LOG.$tc.$background -i $NET_INTERFACE >> $TCMMD_LOG 2>&1 &
     TCMMD_PID=$!
     ROOT_PROC_KILL_LIST+=($TCMMD_PID)