// LinkList gets a list of link devices.
// Equivalent to: `ip link show`
func LinkList() ([]Link, error) {
	// NOTE(vish): This duplicates functionality in net/iface_linux.go, but we need
	//             to get the message ourselves to parse link type.
	req := nl.NewNetlinkRequest(syscall.RTM_GETLINK, syscall.NLM_F_DUMP)

	msg := nl.NewIfInfomsg(syscall.AF_UNSPEC)
	req.AddData(msg)

	msgs, err := req.Execute(syscall.NETLINK_ROUTE, syscall.RTM_NEWLINK)
	if err != nil {
		return nil, err
	}

	res := make([]Link, 0)

	for _, m := range msgs {
		link, err := linkDeserialize(m)
		if err != nil {
			return nil, err
		}
		res = append(res, link)
	}

	return res, nil
}

// XfrmPolicyAdd will add an xfrm policy to the system.
// Equivalent to: `ip xfrm policy add $policy`
func XfrmPolicyAdd(policy *XfrmPolicy) error {
	req := nl.NewNetlinkRequest(nl.XFRM_MSG_NEWPOLICY, syscall.NLM_F_CREATE|syscall.NLM_F_EXCL|syscall.NLM_F_ACK)

	msg := &nl.XfrmUserpolicyInfo{}
	selFromPolicy(&msg.Sel, policy)
	msg.Priority = uint32(policy.Priority)
	msg.Index = uint32(policy.Index)
	msg.Dir = uint8(policy.Dir)
	msg.Lft.SoftByteLimit = nl.XFRM_INF
	msg.Lft.HardByteLimit = nl.XFRM_INF
	msg.Lft.SoftPacketLimit = nl.XFRM_INF
	msg.Lft.HardPacketLimit = nl.XFRM_INF
	req.AddData(msg)

	tmplData := make([]byte, nl.SizeofXfrmUserTmpl*len(policy.Tmpls))
	for i, tmpl := range policy.Tmpls {
		start := i * nl.SizeofXfrmUserTmpl
		userTmpl := nl.DeserializeXfrmUserTmpl(tmplData[start : start+nl.SizeofXfrmUserTmpl])
		userTmpl.XfrmId.Daddr.FromIP(tmpl.Dst)
		userTmpl.Saddr.FromIP(tmpl.Src)
		userTmpl.XfrmId.Proto = uint8(tmpl.Proto)
		userTmpl.Mode = uint8(tmpl.Mode)
		userTmpl.Reqid = uint32(tmpl.Reqid)
		userTmpl.Aalgos = ^uint32(0)
		userTmpl.Ealgos = ^uint32(0)
		userTmpl.Calgos = ^uint32(0)
	}
	if len(tmplData) > 0 {
		tmpls := nl.NewRtAttr(nl.XFRMA_TMPL, tmplData)
		req.AddData(tmpls)
	}

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

// ClassAdd will add a class to the system.
// Equivalent to: `tc class add $class`
func ClassAdd(class Class) error {
	req := nl.NewNetlinkRequest(syscall.RTM_NEWTCLASS, syscall.NLM_F_CREATE|syscall.NLM_F_EXCL|syscall.NLM_F_ACK)
	base := class.Attrs()
	msg := &nl.TcMsg{
		Family:  nl.FAMILY_ALL,
		Ifindex: int32(base.LinkIndex),
		Handle:  base.Handle,
		Parent:  base.Parent,
	}
	req.AddData(msg)
	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)
	_, err := req.Execute(syscall.NETLINK_ROUTE, 0)
	return err
}

// NeighList gets a list of IP-MAC mappings in the system (ARP table).
// Equivalent to: `ip neighbor show`.
// The list can be filtered by link and ip family.
func NeighList(linkIndex, family int) ([]Neigh, error) {
	req := nl.NewNetlinkRequest(syscall.RTM_GETNEIGH, syscall.NLM_F_DUMP)
	msg := Ndmsg{
		Family: uint8(family),
	}
	req.AddData(&msg)

	msgs, err := req.Execute(syscall.NETLINK_ROUTE, syscall.RTM_NEWNEIGH)
	if err != nil {
		return nil, err
	}

	res := make([]Neigh, 0)
	for _, m := range msgs {
		ndm := deserializeNdmsg(m)
		if linkIndex != 0 && int(ndm.Index) != linkIndex {
			// Ignore messages from other interfaces
			continue
		}

		neigh, err := NeighDeserialize(m)
		if err != nil {
			continue
		}

		res = append(res, *neigh)
	}

	return res, nil
}

// LinkByIndex finds a link by index and returns a pointer to the object.
func LinkByIndex(index int) (Link, error) {
	req := nl.NewNetlinkRequest(syscall.RTM_GETLINK, syscall.NLM_F_ACK)

	msg := nl.NewIfInfomsg(syscall.AF_UNSPEC)
	msg.Index = int32(index)
	req.AddData(msg)

	return execGetLink(req)
}

// RouteGet gets a route to a specific destination from the host system.
// Equivalent to: 'ip route get'.
func RouteGet(destination net.IP) ([]Route, error) {
	req := nl.NewNetlinkRequest(syscall.RTM_GETROUTE, syscall.NLM_F_REQUEST)
	family := nl.GetIPFamily(destination)
	var destinationData []byte
	var bitlen uint8
	if family == FAMILY_V4 {
		destinationData = destination.To4()
		bitlen = 32
	} else {
		destinationData = destination.To16()
		bitlen = 128
	}
	msg := &nl.RtMsg{}
	msg.Family = uint8(family)
	msg.Dst_len = bitlen
	req.AddData(msg)

	rtaDst := nl.NewRtAttr(syscall.RTA_DST, destinationData)
	req.AddData(rtaDst)

	msgs, err := req.Execute(syscall.NETLINK_ROUTE, syscall.RTM_NEWROUTE)
	if err != nil {
		return nil, err
	}

	native := nl.NativeEndian()
	res := make([]Route, 0)
	for _, m := range msgs {
		msg := nl.DeserializeRtMsg(m)
		attrs, err := nl.ParseRouteAttr(m[msg.Len():])
		if err != nil {
			return nil, err
		}

		route := Route{}
		for _, attr := range attrs {
			switch attr.Attr.Type {
			case syscall.RTA_GATEWAY:
				route.Gw = net.IP(attr.Value)
			case syscall.RTA_PREFSRC:
				route.Src = net.IP(attr.Value)
			case syscall.RTA_DST:
				route.Dst = &net.IPNet{
					IP:   attr.Value,
					Mask: net.CIDRMask(int(msg.Dst_len), 8*len(attr.Value)),
				}
			case syscall.RTA_OIF:
				routeIndex := int(native.Uint32(attr.Value[0:4]))
				route.LinkIndex = routeIndex
			}
		}
		res = append(res, route)
	}
	return res, nil

}

// XfrmPolicyDel will delete an xfrm policy from the system. Note that
// the Tmpls are ignored when matching the policy to delete.
// Equivalent to: `ip xfrm policy del $policy`
func XfrmPolicyDel(policy *XfrmPolicy) error {
	req := nl.NewNetlinkRequest(nl.XFRM_MSG_DELPOLICY, syscall.NLM_F_ACK)

	msg := &nl.XfrmUserpolicyId{}
	selFromPolicy(&msg.Sel, policy)
	msg.Index = uint32(policy.Index)
	msg.Dir = uint8(policy.Dir)
	req.AddData(msg)

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

// XfrmPolicyList gets a list of xfrm policies in the system.
// Equivalent to: `ip xfrm policy show`.
// The list can be filtered by ip family.
func XfrmPolicyList(family int) ([]XfrmPolicy, error) {
	req := nl.NewNetlinkRequest(nl.XFRM_MSG_GETPOLICY, syscall.NLM_F_DUMP)

	msg := nl.NewIfInfomsg(family)
	req.AddData(msg)

	msgs, err := req.Execute(syscall.NETLINK_XFRM, nl.XFRM_MSG_NEWPOLICY)
	if err != nil {
		return nil, err
	}

	var res []XfrmPolicy
	for _, m := range msgs {
		msg := nl.DeserializeXfrmUserpolicyInfo(m)

		if family != FAMILY_ALL && family != int(msg.Sel.Family) {
			continue
		}

		var policy XfrmPolicy

		policy.Dst = msg.Sel.Daddr.ToIPNet(msg.Sel.PrefixlenD)
		policy.Src = msg.Sel.Saddr.ToIPNet(msg.Sel.PrefixlenS)
		policy.Priority = int(msg.Priority)
		policy.Index = int(msg.Index)
		policy.Dir = Dir(msg.Dir)

		attrs, err := nl.ParseRouteAttr(m[msg.Len():])
		if err != nil {
			return nil, err
		}

		for _, attr := range attrs {
			switch attr.Attr.Type {
			case nl.XFRMA_TMPL:
				max := len(attr.Value)
				for i := 0; i < max; i += nl.SizeofXfrmUserTmpl {
					var resTmpl XfrmPolicyTmpl
					tmpl := nl.DeserializeXfrmUserTmpl(attr.Value[i : i+nl.SizeofXfrmUserTmpl])
					resTmpl.Dst = tmpl.XfrmId.Daddr.ToIP()
					resTmpl.Src = tmpl.Saddr.ToIP()
					resTmpl.Proto = Proto(tmpl.XfrmId.Proto)
					resTmpl.Mode = Mode(tmpl.Mode)
					resTmpl.Reqid = int(tmpl.Reqid)
					policy.Tmpls = append(policy.Tmpls, resTmpl)
				}
			}
		}
		res = append(res, policy)
	}
	return res, nil
}

func LinkGetProtinfo(link Link) (Protinfo, error) {
	base := link.Attrs()
	ensureIndex(base)
	var pi Protinfo
	req := nl.NewNetlinkRequest(syscall.RTM_GETLINK, syscall.NLM_F_DUMP)
	msg := nl.NewIfInfomsg(syscall.AF_BRIDGE)
	req.AddData(msg)
	msgs, err := req.Execute(syscall.NETLINK_ROUTE, 0)
	if err != nil {
		return pi, err
	}

	for _, m := range msgs {
		ans := nl.DeserializeIfInfomsg(m)
		if int(ans.Index) != base.Index {
			continue
		}
		attrs, err := nl.ParseRouteAttr(m[ans.Len():])
		if err != nil {
			return pi, err
		}
		for _, attr := range attrs {
			if attr.Attr.Type != syscall.IFLA_PROTINFO|syscall.NLA_F_NESTED {
				continue
			}
			infos, err := nl.ParseRouteAttr(attr.Value)
			if err != nil {
				return pi, err
			}
			var pi Protinfo
			for _, info := range infos {
				switch info.Attr.Type {
				case nl.IFLA_BRPORT_MODE:
					pi.Hairpin = byteToBool(info.Value[0])
				case nl.IFLA_BRPORT_GUARD:
					pi.Guard = byteToBool(info.Value[0])
				case nl.IFLA_BRPORT_FAST_LEAVE:
					pi.FastLeave = byteToBool(info.Value[0])
				case nl.IFLA_BRPORT_PROTECT:
					pi.RootBlock = byteToBool(info.Value[0])
				case nl.IFLA_BRPORT_LEARNING:
					pi.Learning = byteToBool(info.Value[0])
				case nl.IFLA_BRPORT_UNICAST_FLOOD:
					pi.Flood = byteToBool(info.Value[0])
				}
			}
			return pi, nil
		}
	}
	return pi, fmt.Errorf("Device with index %d not found", base.Index)
}

// LinkDel deletes link device. Either Index or Name must be set in
// the link object for it to be deleted. The other values are ignored.
// Equivalent to: `ip link del $link`
func LinkDel(link Link) error {
	base := link.Attrs()

	ensureIndex(base)

	req := nl.NewNetlinkRequest(syscall.RTM_DELLINK, syscall.NLM_F_ACK)

	msg := nl.NewIfInfomsg(syscall.AF_UNSPEC)
	msg.Index = int32(base.Index)
	req.AddData(msg)

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

// ClassDel will delete a class from the system.
// Equivalent to: `tc class del $class`
func ClassDel(class Class) error {
	req := nl.NewNetlinkRequest(syscall.RTM_DELTCLASS, syscall.NLM_F_ACK)
	base := class.Attrs()
	msg := &nl.TcMsg{
		Family:  nl.FAMILY_ALL,
		Ifindex: int32(base.LinkIndex),
		Handle:  base.Handle,
		Parent:  base.Parent,
	}
	req.AddData(msg)

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

// LinkSetDown disables link device.
// Equivalent to: `ip link set $link down`
func LinkSetDown(link Link) error {
	base := link.Attrs()
	ensureIndex(base)
	req := nl.NewNetlinkRequest(syscall.RTM_NEWLINK, syscall.NLM_F_ACK)

	msg := nl.NewIfInfomsg(syscall.AF_UNSPEC)
	msg.Change = syscall.IFF_UP
	msg.Flags = 0 & ^syscall.IFF_UP
	msg.Index = int32(base.Index)
	req.AddData(msg)

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

// LinkSetHardwareAddr sets the hardware address of the link device.
// Equivalent to: `ip link set $link address $hwaddr`
func LinkSetHardwareAddr(link Link, hwaddr net.HardwareAddr) error {
	base := link.Attrs()
	ensureIndex(base)
	req := nl.NewNetlinkRequest(syscall.RTM_SETLINK, syscall.NLM_F_ACK)

	msg := nl.NewIfInfomsg(syscall.AF_UNSPEC)
	msg.Index = int32(base.Index)
	req.AddData(msg)

	data := nl.NewRtAttr(syscall.IFLA_ADDRESS, []byte(hwaddr))
	req.AddData(data)

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

// FilterDel will delete a filter from the system.
// Equivalent to: `tc filter del $filter`
func FilterDel(filter Filter) error {
	req := nl.NewNetlinkRequest(syscall.RTM_DELTFILTER, syscall.NLM_F_ACK)
	base := filter.Attrs()
	msg := &nl.TcMsg{
		Family:  nl.FAMILY_ALL,
		Ifindex: int32(base.LinkIndex),
		Handle:  base.Handle,
		Parent:  base.Parent,
		Info:    MakeHandle(base.Priority, nl.Swap16(base.Protocol)),
	}
	req.AddData(msg)

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

// LinkSetName sets the name of the link device.
// Equivalent to: `ip link set $link name $name`
func LinkSetName(link Link, name string) error {
	base := link.Attrs()
	ensureIndex(base)
	req := nl.NewNetlinkRequest(syscall.RTM_SETLINK, syscall.NLM_F_ACK)

	msg := nl.NewIfInfomsg(syscall.AF_UNSPEC)
	msg.Index = int32(base.Index)
	req.AddData(msg)

	data := nl.NewRtAttr(syscall.IFLA_IFNAME, []byte(name))
	req.AddData(data)

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

// RouteList gets a list of routes in the system.
// Equivalent to: `ip route show`.
// The list can be filtered by link and ip family.
func RouteList(link Link, family int) ([]Route, error) {
	req := nl.NewNetlinkRequest(syscall.RTM_GETROUTE, syscall.NLM_F_DUMP)
	msg := nl.NewIfInfomsg(family)
	req.AddData(msg)

	msgs, err := req.Execute(syscall.NETLINK_ROUTE, syscall.RTM_NEWROUTE)
	if err != nil {
		return nil, err
	}

	index := 0
	if link != nil {
		base := link.Attrs()
		ensureIndex(base)
		index = base.Index
	}

	var res []Route
	for _, m := range msgs {
		msg := nl.DeserializeRtMsg(m)

		if msg.Flags&syscall.RTM_F_CLONED != 0 {
			// Ignore cloned routes
			continue
		}

		if msg.Table != syscall.RT_TABLE_MAIN {
			// Ignore non-main tables
			continue
		}

		route, err := deserializeRoute(m)
		if err != nil {
			return nil, err
		}

		if link != nil && route.LinkIndex != index {
			// Ignore routes from other interfaces
			continue
		}
		res = append(res, route)
	}

	return res, nil
}

func setProtinfoAttr(link Link, mode bool, attr int) error {
	base := link.Attrs()
	ensureIndex(base)
	req := nl.NewNetlinkRequest(syscall.RTM_SETLINK, syscall.NLM_F_ACK)

	msg := nl.NewIfInfomsg(syscall.AF_BRIDGE)
	msg.Index = int32(base.Index)
	req.AddData(msg)

	br := nl.NewRtAttr(syscall.IFLA_PROTINFO|syscall.NLA_F_NESTED, nil)
	nl.NewRtAttrChild(br, attr, boolToByte(mode))
	req.AddData(br)
	_, err := req.Execute(syscall.NETLINK_ROUTE, 0)
	if err != nil {
		return err
	}
	return nil
}

// LinkSetMTU sets the mtu of the link device.
// Equivalent to: `ip link set $link mtu $mtu`
func LinkSetMTU(link Link, mtu int) error {
	base := link.Attrs()
	ensureIndex(base)
	req := nl.NewNetlinkRequest(syscall.RTM_SETLINK, syscall.NLM_F_ACK)

	msg := nl.NewIfInfomsg(syscall.AF_UNSPEC)
	msg.Index = int32(base.Index)
	req.AddData(msg)

	b := make([]byte, 4)
	native.PutUint32(b, uint32(mtu))

	data := nl.NewRtAttr(syscall.IFLA_MTU, b)
	req.AddData(data)

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

// XfrmStateAdd will add an xfrm state to the system.
// Equivalent to: `ip xfrm state add $state`
func XfrmStateAdd(state *XfrmState) error {
	// A state with spi 0 can't be deleted so don't allow it to be set
	if state.Spi == 0 {
		return fmt.Errorf("Spi must be set when adding xfrm state.")
	}
	req := nl.NewNetlinkRequest(nl.XFRM_MSG_NEWSA, syscall.NLM_F_CREATE|syscall.NLM_F_EXCL|syscall.NLM_F_ACK)

	msg := &nl.XfrmUsersaInfo{}
	msg.Family = uint16(nl.GetIPFamily(state.Dst))
	msg.Id.Daddr.FromIP(state.Dst)
	msg.Saddr.FromIP(state.Src)
	msg.Id.Proto = uint8(state.Proto)
	msg.Mode = uint8(state.Mode)
	msg.Id.Spi = nl.Swap32(uint32(state.Spi))
	msg.Reqid = uint32(state.Reqid)
	msg.ReplayWindow = uint8(state.ReplayWindow)
	msg.Lft.SoftByteLimit = nl.XFRM_INF
	msg.Lft.HardByteLimit = nl.XFRM_INF
	msg.Lft.SoftPacketLimit = nl.XFRM_INF
	msg.Lft.HardPacketLimit = nl.XFRM_INF
	req.AddData(msg)

	if state.Auth != nil {
		out := nl.NewRtAttr(nl.XFRMA_ALG_AUTH_TRUNC, writeStateAlgoAuth(state.Auth))
		req.AddData(out)
	}
	if state.Crypt != nil {
		out := nl.NewRtAttr(nl.XFRMA_ALG_CRYPT, writeStateAlgo(state.Crypt))
		req.AddData(out)
	}
	if state.Encap != nil {
		encapData := make([]byte, nl.SizeofXfrmEncapTmpl)
		encap := nl.DeserializeXfrmEncapTmpl(encapData)
		encap.EncapType = uint16(state.Encap.Type)
		encap.EncapSport = nl.Swap16(uint16(state.Encap.SrcPort))
		encap.EncapDport = nl.Swap16(uint16(state.Encap.DstPort))
		encap.EncapOa.FromIP(state.Encap.OriginalAddress)
		out := nl.NewRtAttr(nl.XFRMA_ENCAP, encapData)
		req.AddData(out)
	}

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

// XfrmStateDel will delete an xfrm state from the system. Note that
// the Algos are ignored when matching the state to delete.
// Equivalent to: `ip xfrm state del $state`
func XfrmStateDel(state *XfrmState) error {
	req := nl.NewNetlinkRequest(nl.XFRM_MSG_DELSA, syscall.NLM_F_ACK)

	msg := &nl.XfrmUsersaId{}
	msg.Daddr.FromIP(state.Dst)
	msg.Family = uint16(nl.GetIPFamily(state.Dst))
	msg.Proto = uint8(state.Proto)
	msg.Spi = nl.Swap32(uint32(state.Spi))
	req.AddData(msg)

	saddr := nl.XfrmAddress{}
	saddr.FromIP(state.Src)
	srcdata := nl.NewRtAttr(nl.XFRMA_SRCADDR, saddr.Serialize())

	req.AddData(srcdata)

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