package netlink
import (
"fmt"
"net"
"syscall"
"unsafe"
"github.com/vishvananda/netlink/nl"
"github.com/vishvananda/netns"
"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_MASTER
NDA_LINK_NETNSID
NDA_SRC_VNI
NDA_PROTOCOL
NDA_NH_ID
NDA_FDB_EXT_ATTRS
NDA_FLAGS_EXT
NDA_MAX = NDA_FLAGS_EXT
)
// 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_EXT_LEARNED = 0x10
NTF_OFFLOADED = 0x20
NTF_STICKY = 0x40
NTF_ROUTER = 0x80
)
// Extended Neighbor Flags
const (
NTF_EXT_MANAGED = 0x00000001
)
// Ndmsg is for adding, removing or receiving information about a neighbor table entry
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.HardwareAddr != nil {
hwData := nl.NewRtAttr(NDA_LLADDR, []byte(neigh.HardwareAddr))
req.AddData(hwData)
}
if neigh.FlagsExt != 0 {
flagsExtData := nl.NewRtAttr(NDA_FLAGS_EXT, nl.Uint32Attr(uint32(neigh.FlagsExt)))
req.AddData(flagsExtData)
}
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)
}
if neigh.MasterIndex != 0 {
masterData := nl.NewRtAttr(NDA_MASTER, nl.Uint32Attr(uint32(neigh.MasterIndex)))
req.AddData(masterData)
}
_, err := req.Execute(unix.NETLINK_ROUTE, 0)
return err
}
// NeighList returns 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 returns 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 returns 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.NeighListExecute(Ndmsg{
Family: uint8(family),
Index: uint32(linkIndex),
})
}
// NeighProxyList returns 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.NeighListExecute(Ndmsg{
Family: uint8(family),
Index: uint32(linkIndex),
Flags: NTF_PROXY,
})
}
// NeighListExecute returns a list of neighbour entries filtered by link, ip family, flag and state.
func NeighListExecute(msg Ndmsg) ([]Neigh, error) {
return pkgHandle.NeighListExecute(msg)
}
// NeighListExecute returns a list of neighbour entries filtered by link, ip family, flag and state.
func (h *Handle) NeighListExecute(msg Ndmsg) ([]Neigh, error) {
req := h.newNetlinkRequest(unix.RTM_GETNEIGH, unix.NLM_F_DUMP)
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 msg.Index != 0 && ndm.Index != msg.Index {
// Ignore messages from other interfaces
continue
}
if msg.Family != 0 && ndm.Family != msg.Family {
continue
}
if msg.State != 0 && ndm.State != msg.State {
continue
}
if msg.Type != 0 && ndm.Type != msg.Type {
continue
}
if msg.Flags != 0 && ndm.Flags != msg.Flags {
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
}
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 {
neigh.LLIPAddr = net.IP(attr.Value)
} else if attrLen == 16 {
// Can be IPv6 or FireWire HWAddr
link, err := LinkByIndex(neigh.LinkIndex)
if err == nil && link.Attrs().EncapType == "tunnel6" {
neigh.IP = net.IP(attr.Value)
} else {
neigh.HardwareAddr = net.HardwareAddr(attr.Value)
}
} else {
neigh.HardwareAddr = net.HardwareAddr(attr.Value)
}
case NDA_FLAGS_EXT:
neigh.FlagsExt = int(native.Uint32(attr.Value[0:4]))
case NDA_VLAN:
neigh.Vlan = int(native.Uint16(attr.Value[0:2]))
case NDA_VNI:
neigh.VNI = int(native.Uint32(attr.Value[0:4]))
case NDA_MASTER:
neigh.MasterIndex = int(native.Uint32(attr.Value[0:4]))
}
}
return &neigh, nil
}
// NeighSubscribe takes a chan down which notifications will be sent
// when neighbors are added or deleted. Close the 'done' chan to stop subscription.
func NeighSubscribe(ch chan<- NeighUpdate, done <-chan struct{}) error {
return neighSubscribeAt(netns.None(), netns.None(), ch, done, nil, false, 0, nil, false)
}
// NeighSubscribeAt works like NeighSubscribe plus it allows the caller
// to choose the network namespace in which to subscribe (ns).
func NeighSubscribeAt(ns netns.NsHandle, ch chan<- NeighUpdate, done <-chan struct{}) error {
return neighSubscribeAt(ns, netns.None(), ch, done, nil, false, 0, nil, false)
}
// NeighSubscribeOptions contains a set of options to use with
// NeighSubscribeWithOptions.
type NeighSubscribeOptions struct {
Namespace *netns.NsHandle
ErrorCallback func(error)
ListExisting bool
// max size is based on value of /proc/sys/net/core/rmem_max
ReceiveBufferSize int
ReceiveBufferForceSize bool
ReceiveTimeout *unix.Timeval
}
// NeighSubscribeWithOptions work like NeighSubscribe but enable to
// provide additional options to modify the behavior. Currently, the
// namespace can be provided as well as an error callback.
func NeighSubscribeWithOptions(ch chan<- NeighUpdate, done <-chan struct{}, options NeighSubscribeOptions) error {
if options.Namespace == nil {
none := netns.None()
options.Namespace = &none
}
return neighSubscribeAt(*options.Namespace, netns.None(), ch, done, options.ErrorCallback, options.ListExisting,
options.ReceiveBufferSize, options.ReceiveTimeout, options.ReceiveBufferForceSize)
}
func neighSubscribeAt(newNs, curNs netns.NsHandle, ch chan<- NeighUpdate, done <-chan struct{}, cberr func(error), listExisting bool,
rcvbuf int, rcvTimeout *unix.Timeval, rcvbufForce bool) error {
s, err := nl.SubscribeAt(newNs, curNs, unix.NETLINK_ROUTE, unix.RTNLGRP_NEIGH)
makeRequest := func(family int) error {
req := pkgHandle.newNetlinkRequest(unix.RTM_GETNEIGH, unix.NLM_F_DUMP)
ndmsg := &Ndmsg{Family: uint8(family)}
req.AddData(ndmsg)
if err := s.Send(req); err != nil {
return err
}
return nil
}
if err != nil {
return err
}
if rcvTimeout != nil {
if err := s.SetReceiveTimeout(rcvTimeout); err != nil {
return err
}
}
if rcvbuf != 0 {
err = s.SetReceiveBufferSize(rcvbuf, rcvbufForce)
if err != nil {
return err
}
}
if done != nil {
go func() {
<-done
s.Close()
}()
}
if listExisting {
if err := makeRequest(unix.AF_UNSPEC); err != nil {
return err
}
// We have to wait for NLMSG_DONE before making AF_BRIDGE request
}
go func() {
defer close(ch)
for {
msgs, from, err := s.Receive()
if err != nil {
if cberr != nil {
cberr(err)
}
return
}
if from.Pid != nl.PidKernel {
if cberr != nil {
cberr(fmt.Errorf("Wrong sender portid %d, expected %d", from.Pid, nl.PidKernel))
}
continue
}
for _, m := range msgs {
if m.Header.Type == unix.NLMSG_DONE {
if listExisting {
// This will be called after handling AF_UNSPEC
// list request, we have to wait for NLMSG_DONE
// before making another request
if err := makeRequest(unix.AF_BRIDGE); err != nil {
if cberr != nil {
cberr(err)
}
return
}
listExisting = false
}
continue
}
if m.Header.Type == unix.NLMSG_ERROR {
nError := int32(native.Uint32(m.Data[0:4]))
if nError == 0 {
continue
}
if cberr != nil {
cberr(syscall.Errno(-nError))
}
return
}
neigh, err := NeighDeserialize(m.Data)
if err != nil {
if cberr != nil {
cberr(err)
}
return
}
ch <- NeighUpdate{Type: m.Header.Type, Neigh: *neigh}
}
}
}()
return nil
}
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