code: func NetworkLinkAddVlan(masterDev, vlanDev string, vlanId uint16) error {
  	s, err := getNetlinkSocket()
  	if err != nil {
  		return err
  	}
  	defer s.Close()
  
  	wb := newNetlinkRequest(syscall.RTM_NEWLINK, syscall.NLM_F_CREATE|syscall.NLM_F_EXCL|syscall.NLM_F_ACK)
  
  	masterDevIfc, err := net.InterfaceByName(masterDev)
  	if err != nil {
  		return err
  	}
  
  	msg := newIfInfomsg(syscall.AF_UNSPEC)
  	wb.AddData(msg)
  
  	nest1 := newRtAttr(syscall.IFLA_LINKINFO, nil)
  	newRtAttrChild(nest1, IFLA_INFO_KIND, nonZeroTerminated("vlan"))
  
  	nest2 := newRtAttrChild(nest1, IFLA_INFO_DATA, nil)
  	vlanData := make([]byte, 2)
  	native.PutUint16(vlanData, vlanId)
  	newRtAttrChild(nest2, IFLA_VLAN_ID, vlanData)
  	wb.AddData(nest1)
  
  	wb.AddData(uint32Attr(syscall.IFLA_LINK, uint32(masterDevIfc.Index)))
  	wb.AddData(newRtAttr(syscall.IFLA_IFNAME, zeroTerminated(vlanDev)))
  
  	if err := s.Send(wb); err != nil {
  		return err
  	}
  	return s.HandleAck(wb.Seq)
  }
docs: // Add a new VLAN interface with masterDev as its upper device
  // This is identical to running:
  // ip link add name $name link $masterdev type vlan id $id