// 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
}

// 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
}

// LinkAdd adds a new link device. The type and features of the device
// are taken fromt the parameters in the link object.
// Equivalent to: `ip link add $link`
func LinkAdd(link Link) error {
	// TODO: set mtu and hardware address
	// TODO: support extra data for macvlan
	base := link.Attrs()

	if base.Name == "" {
		return fmt.Errorf("LinkAttrs.Name cannot be empty!")
	}

	req := nl.NewNetlinkRequest(syscall.RTM_NEWLINK, syscall.NLM_F_CREATE|syscall.NLM_F_EXCL|syscall.NLM_F_ACK)

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

	if base.ParentIndex != 0 {
		b := make([]byte, 4)
		native.PutUint32(b, uint32(base.ParentIndex))
		data := nl.NewRtAttr(syscall.IFLA_LINK, b)
		req.AddData(data)
	}

	nameData := nl.NewRtAttr(syscall.IFLA_IFNAME, nl.ZeroTerminated(base.Name))
	req.AddData(nameData)

	linkInfo := nl.NewRtAttr(syscall.IFLA_LINKINFO, nil)
	nl.NewRtAttrChild(linkInfo, nl.IFLA_INFO_KIND, nl.NonZeroTerminated(link.Type()))

	nl.NewRtAttrChild(linkInfo, syscall.IFLA_TXQLEN, nl.Uint32Attr(base.TxQLen))

	if vlan, ok := link.(*Vlan); ok {
		b := make([]byte, 2)
		native.PutUint16(b, uint16(vlan.VlanId))
		data := nl.NewRtAttrChild(linkInfo, nl.IFLA_INFO_DATA, nil)
		nl.NewRtAttrChild(data, nl.IFLA_VLAN_ID, b)
	} else if veth, ok := link.(*Veth); ok {
		data := nl.NewRtAttrChild(linkInfo, nl.IFLA_INFO_DATA, nil)
		peer := nl.NewRtAttrChild(data, nl.VETH_INFO_PEER, nil)
		nl.NewIfInfomsgChild(peer, syscall.AF_UNSPEC)
		nl.NewRtAttrChild(peer, syscall.IFLA_IFNAME, nl.ZeroTerminated(veth.PeerName))
		nl.NewRtAttrChild(peer, syscall.IFLA_TXQLEN, nl.Uint32Attr(base.TxQLen))
	} else if vxlan, ok := link.(*Vxlan); ok {
		addVxlanAttrs(vxlan, linkInfo)
	}

	req.AddData(linkInfo)

	_, err := req.Execute(syscall.NETLINK_ROUTE, 0)
	if err != nil {
		return err
	}

	ensureIndex(base)

	// can't set master during create, so set it afterwards
	if base.MasterIndex != 0 {
		// TODO: verify MasterIndex is actually a bridge?
		return LinkSetMasterByIndex(link, base.MasterIndex)
	}
	return 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
}

// 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
	}

	res := make([]XfrmPolicy, 0)
	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
}

// LinkAdd adds a new 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
}

// LinkSetUp 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
}

// AddrList gets a list of IP addresses in the system.
// Equivalent to: `ip addr show`.
// The list can be filtered by link and ip family.
func AddrList(link Link, family int) ([]Addr, error) {
	req := nl.NewNetlinkRequest(syscall.RTM_GETADDR, syscall.NLM_F_DUMP)
	msg := nl.NewIfInfomsg(family)
	req.AddData(msg)

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

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

	res := make([]Addr, 0)
	for _, m := range msgs {
		msg := nl.DeserializeIfAddrmsg(m)

		if link != nil && msg.Index != uint32(index) {
			// Ignore messages from other interfaces
			continue
		}

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

		var addr Addr
		for _, attr := range attrs {
			switch attr.Attr.Type {
			case syscall.IFA_ADDRESS:
				addr.IPNet = &net.IPNet{
					IP:   attr.Value,
					Mask: net.CIDRMask(int(msg.Prefixlen), 8*len(attr.Value)),
				}
			case syscall.IFA_LABEL:
				addr.Label = string(attr.Value[:len(attr.Value)-1])
			}
		}
		res = append(res, addr)
	}

	return res, nil
}

// 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.Type = syscall.RTM_SETLINK
	msg.Flags = syscall.NLM_F_REQUEST
	msg.Index = int32(base.Index)
	msg.Change = nl.DEFAULT_CHANGE
	req.AddData(msg)

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

// 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.Type = syscall.RTM_SETLINK
	msg.Flags = syscall.NLM_F_REQUEST
	msg.Index = int32(base.Index)
	msg.Change = nl.DEFAULT_CHANGE
	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
}

// LinkByName finds a link by name and returns a pointer to the object.
func LinkByName(name string) (Link, error) {
	if lookupByDump {
		return linkByNameDump(name)
	}

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

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

	nameData := nl.NewRtAttr(syscall.IFLA_IFNAME, nl.ZeroTerminated(name))
	req.AddData(nameData)

	link, err := execGetLink(req)
	if err == syscall.EINVAL {
		// older kernels don't support looking up via IFLA_IFNAME
		// so fall back to dumping all links
		lookupByDump = true
		return linkByNameDump(name)
	}

	return link, err
}

// RouteAdd will delete a route from the system.
// Equivalent to: `ip route del $route`
func RouteDel(route *Route) error {
	req := nl.NewNetlinkRequest(syscall.RTM_DELROUTE, syscall.NLM_F_ACK)
	return routeHandle(route, req)
}

// AddrAdd will add an IP address to a link device.
// Equivalent to: `ip addr add $addr dev $link`
func AddrAdd(link Link, addr *Addr) error {

	req := nl.NewNetlinkRequest(syscall.RTM_NEWADDR, syscall.NLM_F_CREATE|syscall.NLM_F_EXCL|syscall.NLM_F_ACK)
	return addrHandle(link, addr, req)
}

// AddrDel will delete an IP address from a link device.
// Equivalent to: `ip addr del $addr dev $link`
func AddrDel(link Link, addr *Addr) error {
	req := nl.NewNetlinkRequest(syscall.RTM_DELADDR, syscall.NLM_F_ACK)
	return addrHandle(link, addr, req)
}

// XfrmStateList gets a list of xfrm states in the system.
// Equivalent to: `ip xfrm state show`.
// The list can be filtered by ip family.
func XfrmStateList(family int) ([]XfrmState, error) {
	req := nl.NewNetlinkRequest(nl.XFRM_MSG_GETSA, syscall.NLM_F_DUMP)

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

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

	res := make([]XfrmState, 0)
	for _, m := range msgs {
		msg := nl.DeserializeXfrmUsersaInfo(m)

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

		var state XfrmState

		state.Dst = msg.Id.Daddr.ToIP()
		state.Src = msg.Saddr.ToIP()
		state.Proto = Proto(msg.Id.Proto)
		state.Mode = Mode(msg.Mode)
		state.Spi = int(nl.Swap32(msg.Id.Spi))
		state.Reqid = int(msg.Reqid)
		state.ReplayWindow = int(msg.ReplayWindow)

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

		for _, attr := range attrs {
			switch attr.Attr.Type {
			case nl.XFRMA_ALG_AUTH, nl.XFRMA_ALG_CRYPT:
				var resAlgo *XfrmStateAlgo
				if attr.Attr.Type == nl.XFRMA_ALG_AUTH {
					if state.Auth == nil {
						state.Auth = new(XfrmStateAlgo)
					}
					resAlgo = state.Auth
				} else {
					state.Crypt = new(XfrmStateAlgo)
					resAlgo = state.Crypt
				}
				algo := nl.DeserializeXfrmAlgo(attr.Value[:])
				(*resAlgo).Name = nl.BytesToString(algo.AlgName[:])
				(*resAlgo).Key = algo.AlgKey
			case nl.XFRMA_ALG_AUTH_TRUNC:
				if state.Auth == nil {
					state.Auth = new(XfrmStateAlgo)
				}
				algo := nl.DeserializeXfrmAlgoAuth(attr.Value[:])
				state.Auth.Name = nl.BytesToString(algo.AlgName[:])
				state.Auth.Key = algo.AlgKey
				state.Auth.TruncateLen = int(algo.AlgTruncLen)
			case nl.XFRMA_ENCAP:
				encap := nl.DeserializeXfrmEncapTmpl(attr.Value[:])
				state.Encap = new(XfrmStateEncap)
				state.Encap.Type = EncapType(encap.EncapType)
				state.Encap.SrcPort = int(nl.Swap16(encap.EncapSport))
				state.Encap.DstPort = int(nl.Swap16(encap.EncapDport))
				state.Encap.OriginalAddress = encap.EncapOa.ToIP()
			}

		}
		res = append(res, state)
	}
	return res, nil
}