func neighHandle(neigh *Neigh, req *nl.NetlinkRequest) error {
	var family int
	if neigh.Family > 0 {
		family = neigh.Family
	} else {
		family = nl.GetIPFamily(neigh.IP)
	}

	msg := Ndmsg{
		Family: uint8(family),
		Index:  uint32(neigh.LinkIndex),
		State:  uint16(neigh.State),
		Type:   uint8(neigh.Type),
		Flags:  uint8(neigh.Flags),
	}
	req.AddData(&msg)

	ipData := neigh.IP.To4()
	if ipData == nil {
		ipData = neigh.IP.To16()
	}

	dstData := nl.NewRtAttr(NDA_DST, ipData)
	req.AddData(dstData)

	hwData := nl.NewRtAttr(NDA_LLADDR, []byte(neigh.HardwareAddr))
	req.AddData(hwData)

	_, err := req.Execute(syscall.NETLINK_ROUTE, 0)
	return err
}

func classPayload(req *nl.NetlinkRequest, class Class) error {
	req.AddData(nl.NewRtAttr(nl.TCA_KIND, nl.ZeroTerminated(class.Type())))

	options := nl.NewRtAttr(nl.TCA_OPTIONS, nil)
	if htb, ok := class.(*HtbClass); ok {
		opt := nl.TcHtbCopt{}
		opt.Rate.Rate = uint32(htb.Rate)
		opt.Ceil.Rate = uint32(htb.Ceil)
		opt.Buffer = htb.Buffer
		opt.Cbuffer = htb.Cbuffer
		opt.Quantum = htb.Quantum
		opt.Level = htb.Level
		opt.Prio = htb.Prio
		// TODO: Handle Debug properly. For now default to 0
		nl.NewRtAttrChild(options, nl.TCA_HTB_PARMS, opt.Serialize())
	}
	req.AddData(options)
	return nil
}

func execGetLink(req *nl.NetlinkRequest) (Link, error) {
	msgs, err := req.Execute(syscall.NETLINK_ROUTE, 0)
	if err != nil {
		if errno, ok := err.(syscall.Errno); ok {
			if errno == syscall.ENODEV {
				return nil, fmt.Errorf("Link not found")
			}
		}
		return nil, err
	}

	switch {
	case len(msgs) == 0:
		return nil, fmt.Errorf("Link not found")

	case len(msgs) == 1:
		return linkDeserialize(msgs[0])

	default:
		return nil, fmt.Errorf("More than one link found")
	}
}

func addrHandle(link Link, addr *Addr, req *nl.NetlinkRequest) error {
	base := link.Attrs()
	if addr.Label != "" && !strings.HasPrefix(addr.Label, base.Name) {
		return fmt.Errorf("label must begin with interface name")
	}
	ensureIndex(base)

	family := nl.GetIPFamily(addr.IP)

	msg := nl.NewIfAddrmsg(family)
	msg.Index = uint32(base.Index)
	prefixlen, _ := addr.Mask.Size()
	msg.Prefixlen = uint8(prefixlen)
	req.AddData(msg)

	var addrData []byte
	if family == FAMILY_V4 {
		addrData = addr.IP.To4()
	} else {
		addrData = addr.IP.To16()
	}

	localData := nl.NewRtAttr(syscall.IFA_LOCAL, addrData)
	req.AddData(localData)

	addressData := nl.NewRtAttr(syscall.IFA_ADDRESS, addrData)
	req.AddData(addressData)

	if addr.Label != "" {
		labelData := nl.NewRtAttr(syscall.IFA_LABEL, nl.ZeroTerminated(addr.Label))
		req.AddData(labelData)
	}

	_, err := req.Execute(syscall.NETLINK_ROUTE, 0)
	return err
}

func routeHandle(route *Route, req *nl.NetlinkRequest) error {
	if (route.Dst == nil || route.Dst.IP == nil) && route.Src == nil && route.Gw == nil {
		return fmt.Errorf("one of Dst.IP, Src, or Gw must not be nil")
	}

	msg := nl.NewRtMsg()
	msg.Scope = uint8(route.Scope)
	family := -1
	var rtAttrs []*nl.RtAttr

	if route.Dst != nil && route.Dst.IP != nil {
		dstLen, _ := route.Dst.Mask.Size()
		msg.Dst_len = uint8(dstLen)
		dstFamily := nl.GetIPFamily(route.Dst.IP)
		family = dstFamily
		var dstData []byte
		if dstFamily == FAMILY_V4 {
			dstData = route.Dst.IP.To4()
		} else {
			dstData = route.Dst.IP.To16()
		}
		rtAttrs = append(rtAttrs, nl.NewRtAttr(syscall.RTA_DST, dstData))
	}

	if route.Src != nil {
		srcFamily := nl.GetIPFamily(route.Src)
		if family != -1 && family != srcFamily {
			return fmt.Errorf("source and destination ip are not the same IP family")
		}
		family = srcFamily
		var srcData []byte
		if srcFamily == FAMILY_V4 {
			srcData = route.Src.To4()
		} else {
			srcData = route.Src.To16()
		}
		// The commonly used src ip for routes is actually PREFSRC
		rtAttrs = append(rtAttrs, nl.NewRtAttr(syscall.RTA_PREFSRC, srcData))
	}

	if route.Gw != nil {
		gwFamily := nl.GetIPFamily(route.Gw)
		if family != -1 && family != gwFamily {
			return fmt.Errorf("gateway, source, and destination ip are not the same IP family")
		}
		family = gwFamily
		var gwData []byte
		if gwFamily == FAMILY_V4 {
			gwData = route.Gw.To4()
		} else {
			gwData = route.Gw.To16()
		}
		rtAttrs = append(rtAttrs, nl.NewRtAttr(syscall.RTA_GATEWAY, gwData))
	}

	msg.Family = uint8(family)

	req.AddData(msg)
	for _, attr := range rtAttrs {
		req.AddData(attr)
	}

	var (
		b      = make([]byte, 4)
		native = nl.NativeEndian()
	)
	native.PutUint32(b, uint32(route.LinkIndex))

	req.AddData(nl.NewRtAttr(syscall.RTA_OIF, b))

	_, err := req.Execute(syscall.NETLINK_ROUTE, 0)
	return err
}

func qdiscPayload(req *nl.NetlinkRequest, qdisc Qdisc) error {

	req.AddData(nl.NewRtAttr(nl.TCA_KIND, nl.ZeroTerminated(qdisc.Type())))

	options := nl.NewRtAttr(nl.TCA_OPTIONS, nil)
	if prio, ok := qdisc.(*Prio); ok {
		tcmap := nl.TcPrioMap{
			Bands:   int32(prio.Bands),
			Priomap: prio.PriorityMap,
		}
		options = nl.NewRtAttr(nl.TCA_OPTIONS, tcmap.Serialize())
	} else if tbf, ok := qdisc.(*Tbf); ok {
		opt := nl.TcTbfQopt{}
		// TODO: handle rate > uint32
		opt.Rate.Rate = uint32(tbf.Rate)
		opt.Limit = tbf.Limit
		opt.Buffer = tbf.Buffer
		nl.NewRtAttrChild(options, nl.TCA_TBF_PARMS, opt.Serialize())
	} else if htb, ok := qdisc.(*Htb); ok {
		opt := nl.TcHtbGlob{}
		opt.Version = htb.Version
		opt.Rate2Quantum = htb.Rate2Quantum
		opt.Defcls = htb.Defcls
		// TODO: Handle Debug properly. For now default to 0
		opt.Debug = htb.Debug
		opt.DirectPkts = htb.DirectPkts
		nl.NewRtAttrChild(options, nl.TCA_HTB_INIT, opt.Serialize())
		// nl.NewRtAttrChild(options, nl.TCA_HTB_DIRECT_QLEN, opt.Serialize())
	} else if netem, ok := qdisc.(*Netem); ok {
		opt := nl.TcNetemQopt{}
		opt.Latency = netem.Latency
		opt.Limit = netem.Limit
		opt.Loss = netem.Loss
		opt.Gap = netem.Gap
		opt.Duplicate = netem.Duplicate
		opt.Jitter = netem.Jitter
		options = nl.NewRtAttr(nl.TCA_OPTIONS, opt.Serialize())
		// Correlation
		corr := nl.TcNetemCorr{}
		corr.DelayCorr = netem.DelayCorr
		corr.LossCorr = netem.LossCorr
		corr.DupCorr = netem.DuplicateCorr

		if corr.DelayCorr > 0 || corr.LossCorr > 0 || corr.DupCorr > 0 {
			nl.NewRtAttrChild(options, nl.TCA_NETEM_CORR, corr.Serialize())
		}
		// Corruption
		corruption := nl.TcNetemCorrupt{}
		corruption.Probability = netem.CorruptProb
		corruption.Correlation = netem.CorruptCorr
		if corruption.Probability > 0 {
			nl.NewRtAttrChild(options, nl.TCA_NETEM_CORRUPT, corruption.Serialize())
		}
		// Reorder
		reorder := nl.TcNetemReorder{}
		reorder.Probability = netem.ReorderProb
		reorder.Correlation = netem.ReorderCorr
		if reorder.Probability > 0 {
			nl.NewRtAttrChild(options, nl.TCA_NETEM_REORDER, reorder.Serialize())
		}
	} else if _, ok := qdisc.(*Ingress); ok {
		// ingress filters must use the proper handle
		if qdisc.Attrs().Parent != HANDLE_INGRESS {
			return fmt.Errorf("Ingress filters must set Parent to HANDLE_INGRESS")
		}
	}

	req.AddData(options)
	return nil
}