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package netlink
import (
"net"
"unsafe"
"github.com/vishvananda/netlink/nl"
"golang.org/x/sys/unix"
)
const (
NDA_UNSPEC = iota
NDA_DST
NDA_LLADDR
NDA_CACHEINFO
NDA_PROBES
NDA_VLAN
NDA_PORT
NDA_VNI
NDA_IFINDEX
NDA_MAX = NDA_IFINDEX
)
// Neighbor Cache Entry States.
const (
NUD_NONE = 0x00
NUD_INCOMPLETE = 0x01
NUD_REACHABLE = 0x02
NUD_STALE = 0x04
NUD_DELAY = 0x08
NUD_PROBE = 0x10
NUD_FAILED = 0x20
NUD_NOARP = 0x40
NUD_PERMANENT = 0x80
)
// Neighbor Flags
const (
NTF_USE = 0x01
NTF_SELF = 0x02
NTF_MASTER = 0x04
NTF_PROXY = 0x08
NTF_ROUTER = 0x80
)
type Ndmsg struct {
Family uint8
Index uint32
State uint16
Flags uint8
Type uint8
}
func deserializeNdmsg(b []byte) *Ndmsg {
var dummy Ndmsg
return (*Ndmsg)(unsafe.Pointer(&b[0:unsafe.Sizeof(dummy)][0]))
}
func (msg *Ndmsg) Serialize() []byte {
return (*(*[unsafe.Sizeof(*msg)]byte)(unsafe.Pointer(msg)))[:]
}
func (msg *Ndmsg) Len() int {
return int(unsafe.Sizeof(*msg))
}
// NeighAdd will add an IP to MAC mapping to the ARP table
// Equivalent to: `ip neigh add ....`
func NeighAdd(neigh *Neigh) error {
return pkgHandle.NeighAdd(neigh)
}
// NeighAdd will add an IP to MAC mapping to the ARP table
// Equivalent to: `ip neigh add ....`
func (h *Handle) NeighAdd(neigh *Neigh) error {
return h.neighAdd(neigh, unix.NLM_F_CREATE|unix.NLM_F_EXCL)
}
// NeighSet will add or replace an IP to MAC mapping to the ARP table
// Equivalent to: `ip neigh replace....`
func NeighSet(neigh *Neigh) error {
return pkgHandle.NeighSet(neigh)
}
// NeighSet will add or replace an IP to MAC mapping to the ARP table
// Equivalent to: `ip neigh replace....`
func (h *Handle) NeighSet(neigh *Neigh) error {
return h.neighAdd(neigh, unix.NLM_F_CREATE|unix.NLM_F_REPLACE)
}
// NeighAppend will append an entry to FDB
// Equivalent to: `bridge fdb append...`
func NeighAppend(neigh *Neigh) error {
return pkgHandle.NeighAppend(neigh)
}
// NeighAppend will append an entry to FDB
// Equivalent to: `bridge fdb append...`
func (h *Handle) NeighAppend(neigh *Neigh) error {
return h.neighAdd(neigh, unix.NLM_F_CREATE|unix.NLM_F_APPEND)
}
// NeighAppend will append an entry to FDB
// Equivalent to: `bridge fdb append...`
func neighAdd(neigh *Neigh, mode int) error {
return pkgHandle.neighAdd(neigh, mode)
}
// NeighAppend will append an entry to FDB
// Equivalent to: `bridge fdb append...`
func (h *Handle) neighAdd(neigh *Neigh, mode int) error {
req := h.newNetlinkRequest(unix.RTM_NEWNEIGH, mode|unix.NLM_F_ACK)
return neighHandle(neigh, req)
}
// NeighDel will delete an IP address from a link device.
// Equivalent to: `ip addr del $addr dev $link`
func NeighDel(neigh *Neigh) error {
return pkgHandle.NeighDel(neigh)
}
// NeighDel will delete an IP address from a link device.
// Equivalent to: `ip addr del $addr dev $link`
func (h *Handle) NeighDel(neigh *Neigh) error {
req := h.newNetlinkRequest(unix.RTM_DELNEIGH, unix.NLM_F_ACK)
return neighHandle(neigh, req)
}
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)
if neigh.LLIPAddr != nil {
llIPData := nl.NewRtAttr(NDA_LLADDR, neigh.LLIPAddr.To4())
req.AddData(llIPData)
} else if neigh.Flags != NTF_PROXY || neigh.HardwareAddr != nil {
hwData := nl.NewRtAttr(NDA_LLADDR, []byte(neigh.HardwareAddr))
req.AddData(hwData)
}
if neigh.Vlan != 0 {
vlanData := nl.NewRtAttr(NDA_VLAN, nl.Uint16Attr(uint16(neigh.Vlan)))
req.AddData(vlanData)
}
if neigh.VNI != 0 {
vniData := nl.NewRtAttr(NDA_VNI, nl.Uint32Attr(uint32(neigh.VNI)))
req.AddData(vniData)
}
_, err := req.Execute(unix.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) {
return pkgHandle.NeighList(linkIndex, family)
}
// NeighProxyList gets a list of neighbor proxies in the system.
// Equivalent to: `ip neighbor show proxy`.
// The list can be filtered by link and ip family.
func NeighProxyList(linkIndex, family int) ([]Neigh, error) {
return pkgHandle.NeighProxyList(linkIndex, family)
}
// 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 (h *Handle) NeighList(linkIndex, family int) ([]Neigh, error) {
return h.neighList(linkIndex, family, 0)
}
// NeighProxyList gets a list of neighbor proxies in the system.
// Equivalent to: `ip neighbor show proxy`.
// The list can be filtered by link, ip family.
func (h *Handle) NeighProxyList(linkIndex, family int) ([]Neigh, error) {
return h.neighList(linkIndex, family, NTF_PROXY)
}
func (h *Handle) neighList(linkIndex, family, flags int) ([]Neigh, error) {
req := h.newNetlinkRequest(unix.RTM_GETNEIGH, unix.NLM_F_DUMP)
msg := Ndmsg{
Family: uint8(family),
Index: uint32(linkIndex),
Flags: uint8(flags),
}
req.AddData(&msg)
msgs, err := req.Execute(unix.NETLINK_ROUTE, unix.RTM_NEWNEIGH)
if err != nil {
return nil, err
}
var res []Neigh
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
}
func NeighDeserialize(m []byte) (*Neigh, error) {
msg := deserializeNdmsg(m)
neigh := Neigh{
LinkIndex: int(msg.Index),
Family: int(msg.Family),
State: int(msg.State),
Type: int(msg.Type),
Flags: int(msg.Flags),
}
attrs, err := nl.ParseRouteAttr(m[msg.Len():])
if err != nil {
return nil, err
}
// This should be cached for perfomance
// once per table dump
link, err := LinkByIndex(neigh.LinkIndex)
if err != nil {
return nil, err
}
encapType := link.Attrs().EncapType
for _, attr := range attrs {
switch attr.Attr.Type {
case NDA_DST:
neigh.IP = net.IP(attr.Value)
case NDA_LLADDR:
// BUG: Is this a bug in the netlink library?
// #define RTA_LENGTH(len) (RTA_ALIGN(sizeof(struct rtattr)) + (len))
// #define RTA_PAYLOAD(rta) ((int)((rta)->rta_len) - RTA_LENGTH(0))
attrLen := attr.Attr.Len - unix.SizeofRtAttr
if attrLen == 4 && (encapType == "ipip" ||
encapType == "sit" ||
encapType == "gre") {
neigh.LLIPAddr = net.IP(attr.Value)
} else if attrLen == 16 &&
encapType == "tunnel6" {
neigh.IP = net.IP(attr.Value)
} else {
neigh.HardwareAddr = net.HardwareAddr(attr.Value)
}
case NDA_VLAN:
neigh.Vlan = int(native.Uint16(attr.Value[0:2]))
case NDA_VNI:
neigh.VNI = int(native.Uint32(attr.Value[0:4]))
}
}
return &neigh, nil
}
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