Measure cable length from hardware transmit and receive timestamps

system.go

@@ -196,7 +196,8 @@ func checkFlowRules(fd int, ifname string, ethertypes []uint16) checkResult {
 	return res
 }
 
-type ethtoolIfreq struct {
+// The ifreq shape used by every ioctl that passes its payload by pointer.
+type dataIfreq struct {
 	name [unix.IFNAMSIZ]byte
 	data unsafe.Pointer
 	_    [16]byte
@@ -283,7 +284,7 @@ func (r checkResult) detail() string {
 }
 
 func ethtoolCall(fd int, ifname string, data unsafe.Pointer) error {
-	var ifr ethtoolIfreq
+	var ifr dataIfreq
 	if len(ifname) >= unix.IFNAMSIZ {
 		return fmt.Errorf("interface name %q too long", ifname)
 	}
@@ -482,6 +483,7 @@ func configureSystem(ifnames []string, ethertypes []uint16) []checkResult {
 			}
 			out = append(out, checkCarrier(ifname, carrierWait))
 			out = append(out, checkCoalesce(fd, ifname, wantCoalesceUsecs, wantCoalesceUsecs))
+			out = append(out, checkTimestamping(fd, ifname))
 			out = append(out, checkFlowRules(fd, ifname, ethertypes))
 		}
 		return out