plugins/traffic-control: separate function for clear settings

Make easier to combine latency and packet loss settings.

examples/plugins/traffic-control/report.go

@@ -285,7 +285,7 @@ func getControls() []extControl {
 				Rank:  24,
 			},
 			handler: func(pid int) error {
-				return DoTrafficControl(pid, "", "")
+				return ClearTrafficControlSettings(pid)
 			},
 		},
 	}

examples/plugins/traffic-control/tc.go

@@ -77,6 +77,52 @@ func DoTrafficControl(pid int, latency string, pktLoss string) error {
 	return nil
 }
 
+func ClearTrafficControlSettings(pid int) error {
+	cmds := [][]string{
+		split("tc qdisc replace dev eth0 root handle 1: netem"),
+
+		// These steps are not required, since we don't do
+		// ingress traffic control, only egress, see the TODO
+		// at the beginning of the file.
+
+		//split("ip link add ifb0 type ifb"),
+		//split("ip link set ifb0 up"),
+		//split("tc qdisc add dev eth0 handle ffff: ingress"),
+		//split("tc filter add dev eth0 parent ffff: protocol ip u32 match u32 0 0 action mirred egress redirect dev ifb0"),
+		//split("tc qdisc replace dev ifb0 handle 1:0 root netem"),
+
+		// Add "loss %d%% rate %dkbit" when we add the
+		// possibility to control the packet loss and
+		// bandwidth. See the TODO at the beginning of the
+		// file.
+
+	}
+	netNS := fmt.Sprintf("/proc/%d/ns/net", pid)
+	err := ns.WithNetNSPath(netNS, func(hostNS ns.NetNS) error {
+		for _, cmd := range cmds {
+			if output, err := exec.Command(cmd[0], cmd[1:]...).CombinedOutput(); err != nil {
+				log.Error(string(output))
+				return fmt.Errorf("failed to execute command: %v", err)
+			}
+		}
+		return nil
+	})
+	if err != nil {
+		return fmt.Errorf("failed to perform traffic control: %v", err)
+	}
+	// clear cached parameters
+	if netNSID, err := getNSID(netNS); err != nil {
+		log.Error(netNSID)
+		return fmt.Errorf("failed to get network namespace ID: %v", err)
+	} else {
+		//trafficControlStatusCache[netNSID] = trafficControlStatus{
+		//	latency: "-",
+		//	pktLoss: "-",
+		delete(trafficControlStatusCache, netNSID)
+	}
+	return nil
+}
+
 func getLatency(pid int) (string, error) {
 	var status *trafficControlStatus
 	var err error