/usr/share/gocode/src/github.com/vishvananda/netlink/nl/nl_linux.go is in golang-github-vishvananda-netlink-dev 0.0~git20170407.0.1e86b2b-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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package nl
import (
"bytes"
"encoding/binary"
"fmt"
"net"
"runtime"
"sync"
"sync/atomic"
"syscall"
"unsafe"
"github.com/vishvananda/netns"
)
const (
// Family type definitions
FAMILY_ALL = syscall.AF_UNSPEC
FAMILY_V4 = syscall.AF_INET
FAMILY_V6 = syscall.AF_INET6
FAMILY_MPLS = AF_MPLS
)
// SupportedNlFamilies contains the list of netlink families this netlink package supports
var SupportedNlFamilies = []int{syscall.NETLINK_ROUTE, syscall.NETLINK_XFRM, syscall.NETLINK_NETFILTER}
var nextSeqNr uint32
// GetIPFamily returns the family type of a net.IP.
func GetIPFamily(ip net.IP) int {
if len(ip) <= net.IPv4len {
return FAMILY_V4
}
if ip.To4() != nil {
return FAMILY_V4
}
return FAMILY_V6
}
var nativeEndian binary.ByteOrder
// Get native endianness for the system
func NativeEndian() binary.ByteOrder {
if nativeEndian == nil {
var x uint32 = 0x01020304
if *(*byte)(unsafe.Pointer(&x)) == 0x01 {
nativeEndian = binary.BigEndian
} else {
nativeEndian = binary.LittleEndian
}
}
return nativeEndian
}
// Byte swap a 16 bit value if we aren't big endian
func Swap16(i uint16) uint16 {
if NativeEndian() == binary.BigEndian {
return i
}
return (i&0xff00)>>8 | (i&0xff)<<8
}
// Byte swap a 32 bit value if aren't big endian
func Swap32(i uint32) uint32 {
if NativeEndian() == binary.BigEndian {
return i
}
return (i&0xff000000)>>24 | (i&0xff0000)>>8 | (i&0xff00)<<8 | (i&0xff)<<24
}
type NetlinkRequestData interface {
Len() int
Serialize() []byte
}
// IfInfomsg is related to links, but it is used for list requests as well
type IfInfomsg struct {
syscall.IfInfomsg
}
// Create an IfInfomsg with family specified
func NewIfInfomsg(family int) *IfInfomsg {
return &IfInfomsg{
IfInfomsg: syscall.IfInfomsg{
Family: uint8(family),
},
}
}
func DeserializeIfInfomsg(b []byte) *IfInfomsg {
return (*IfInfomsg)(unsafe.Pointer(&b[0:syscall.SizeofIfInfomsg][0]))
}
func (msg *IfInfomsg) Serialize() []byte {
return (*(*[syscall.SizeofIfInfomsg]byte)(unsafe.Pointer(msg)))[:]
}
func (msg *IfInfomsg) Len() int {
return syscall.SizeofIfInfomsg
}
func (msg *IfInfomsg) EncapType() string {
switch msg.Type {
case 0:
return "generic"
case syscall.ARPHRD_ETHER:
return "ether"
case syscall.ARPHRD_EETHER:
return "eether"
case syscall.ARPHRD_AX25:
return "ax25"
case syscall.ARPHRD_PRONET:
return "pronet"
case syscall.ARPHRD_CHAOS:
return "chaos"
case syscall.ARPHRD_IEEE802:
return "ieee802"
case syscall.ARPHRD_ARCNET:
return "arcnet"
case syscall.ARPHRD_APPLETLK:
return "atalk"
case syscall.ARPHRD_DLCI:
return "dlci"
case syscall.ARPHRD_ATM:
return "atm"
case syscall.ARPHRD_METRICOM:
return "metricom"
case syscall.ARPHRD_IEEE1394:
return "ieee1394"
case syscall.ARPHRD_INFINIBAND:
return "infiniband"
case syscall.ARPHRD_SLIP:
return "slip"
case syscall.ARPHRD_CSLIP:
return "cslip"
case syscall.ARPHRD_SLIP6:
return "slip6"
case syscall.ARPHRD_CSLIP6:
return "cslip6"
case syscall.ARPHRD_RSRVD:
return "rsrvd"
case syscall.ARPHRD_ADAPT:
return "adapt"
case syscall.ARPHRD_ROSE:
return "rose"
case syscall.ARPHRD_X25:
return "x25"
case syscall.ARPHRD_HWX25:
return "hwx25"
case syscall.ARPHRD_PPP:
return "ppp"
case syscall.ARPHRD_HDLC:
return "hdlc"
case syscall.ARPHRD_LAPB:
return "lapb"
case syscall.ARPHRD_DDCMP:
return "ddcmp"
case syscall.ARPHRD_RAWHDLC:
return "rawhdlc"
case syscall.ARPHRD_TUNNEL:
return "ipip"
case syscall.ARPHRD_TUNNEL6:
return "tunnel6"
case syscall.ARPHRD_FRAD:
return "frad"
case syscall.ARPHRD_SKIP:
return "skip"
case syscall.ARPHRD_LOOPBACK:
return "loopback"
case syscall.ARPHRD_LOCALTLK:
return "ltalk"
case syscall.ARPHRD_FDDI:
return "fddi"
case syscall.ARPHRD_BIF:
return "bif"
case syscall.ARPHRD_SIT:
return "sit"
case syscall.ARPHRD_IPDDP:
return "ip/ddp"
case syscall.ARPHRD_IPGRE:
return "gre"
case syscall.ARPHRD_PIMREG:
return "pimreg"
case syscall.ARPHRD_HIPPI:
return "hippi"
case syscall.ARPHRD_ASH:
return "ash"
case syscall.ARPHRD_ECONET:
return "econet"
case syscall.ARPHRD_IRDA:
return "irda"
case syscall.ARPHRD_FCPP:
return "fcpp"
case syscall.ARPHRD_FCAL:
return "fcal"
case syscall.ARPHRD_FCPL:
return "fcpl"
case syscall.ARPHRD_FCFABRIC:
return "fcfb0"
case syscall.ARPHRD_FCFABRIC + 1:
return "fcfb1"
case syscall.ARPHRD_FCFABRIC + 2:
return "fcfb2"
case syscall.ARPHRD_FCFABRIC + 3:
return "fcfb3"
case syscall.ARPHRD_FCFABRIC + 4:
return "fcfb4"
case syscall.ARPHRD_FCFABRIC + 5:
return "fcfb5"
case syscall.ARPHRD_FCFABRIC + 6:
return "fcfb6"
case syscall.ARPHRD_FCFABRIC + 7:
return "fcfb7"
case syscall.ARPHRD_FCFABRIC + 8:
return "fcfb8"
case syscall.ARPHRD_FCFABRIC + 9:
return "fcfb9"
case syscall.ARPHRD_FCFABRIC + 10:
return "fcfb10"
case syscall.ARPHRD_FCFABRIC + 11:
return "fcfb11"
case syscall.ARPHRD_FCFABRIC + 12:
return "fcfb12"
case syscall.ARPHRD_IEEE802_TR:
return "tr"
case syscall.ARPHRD_IEEE80211:
return "ieee802.11"
case syscall.ARPHRD_IEEE80211_PRISM:
return "ieee802.11/prism"
case syscall.ARPHRD_IEEE80211_RADIOTAP:
return "ieee802.11/radiotap"
case syscall.ARPHRD_IEEE802154:
return "ieee802.15.4"
case 65534:
return "none"
case 65535:
return "void"
}
return fmt.Sprintf("unknown%d", msg.Type)
}
func rtaAlignOf(attrlen int) int {
return (attrlen + syscall.RTA_ALIGNTO - 1) & ^(syscall.RTA_ALIGNTO - 1)
}
func NewIfInfomsgChild(parent *RtAttr, family int) *IfInfomsg {
msg := NewIfInfomsg(family)
parent.children = append(parent.children, msg)
return msg
}
// Extend RtAttr to handle data and children
type RtAttr struct {
syscall.RtAttr
Data []byte
children []NetlinkRequestData
}
// Create a new Extended RtAttr object
func NewRtAttr(attrType int, data []byte) *RtAttr {
return &RtAttr{
RtAttr: syscall.RtAttr{
Type: uint16(attrType),
},
children: []NetlinkRequestData{},
Data: data,
}
}
// Create a new RtAttr obj anc add it as a child of an existing object
func NewRtAttrChild(parent *RtAttr, attrType int, data []byte) *RtAttr {
attr := NewRtAttr(attrType, data)
parent.children = append(parent.children, attr)
return attr
}
func (a *RtAttr) Len() int {
if len(a.children) == 0 {
return (syscall.SizeofRtAttr + len(a.Data))
}
l := 0
for _, child := range a.children {
l += rtaAlignOf(child.Len())
}
l += syscall.SizeofRtAttr
return rtaAlignOf(l + len(a.Data))
}
// Serialize the RtAttr into a byte array
// This can't just unsafe.cast because it must iterate through children.
func (a *RtAttr) Serialize() []byte {
native := NativeEndian()
length := a.Len()
buf := make([]byte, rtaAlignOf(length))
next := 4
if a.Data != nil {
copy(buf[next:], a.Data)
next += rtaAlignOf(len(a.Data))
}
if len(a.children) > 0 {
for _, child := range a.children {
childBuf := child.Serialize()
copy(buf[next:], childBuf)
next += rtaAlignOf(len(childBuf))
}
}
if l := uint16(length); l != 0 {
native.PutUint16(buf[0:2], l)
}
native.PutUint16(buf[2:4], a.Type)
return buf
}
type NetlinkRequest struct {
syscall.NlMsghdr
Data []NetlinkRequestData
RawData []byte
Sockets map[int]*SocketHandle
}
// Serialize the Netlink Request into a byte array
func (req *NetlinkRequest) Serialize() []byte {
length := syscall.SizeofNlMsghdr
dataBytes := make([][]byte, len(req.Data))
for i, data := range req.Data {
dataBytes[i] = data.Serialize()
length = length + len(dataBytes[i])
}
length += len(req.RawData)
req.Len = uint32(length)
b := make([]byte, length)
hdr := (*(*[syscall.SizeofNlMsghdr]byte)(unsafe.Pointer(req)))[:]
next := syscall.SizeofNlMsghdr
copy(b[0:next], hdr)
for _, data := range dataBytes {
for _, dataByte := range data {
b[next] = dataByte
next = next + 1
}
}
// Add the raw data if any
if len(req.RawData) > 0 {
copy(b[next:length], req.RawData)
}
return b
}
func (req *NetlinkRequest) AddData(data NetlinkRequestData) {
if data != nil {
req.Data = append(req.Data, data)
}
}
// AddRawData adds raw bytes to the end of the NetlinkRequest object during serialization
func (req *NetlinkRequest) AddRawData(data []byte) {
if data != nil {
req.RawData = append(req.RawData, data...)
}
}
// Execute the request against a the given sockType.
// Returns a list of netlink messages in serialized format, optionally filtered
// by resType.
func (req *NetlinkRequest) Execute(sockType int, resType uint16) ([][]byte, error) {
var (
s *NetlinkSocket
err error
)
if req.Sockets != nil {
if sh, ok := req.Sockets[sockType]; ok {
s = sh.Socket
req.Seq = atomic.AddUint32(&sh.Seq, 1)
}
}
sharedSocket := s != nil
if s == nil {
s, err = getNetlinkSocket(sockType)
if err != nil {
return nil, err
}
defer s.Close()
} else {
s.Lock()
defer s.Unlock()
}
if err := s.Send(req); err != nil {
return nil, err
}
pid, err := s.GetPid()
if err != nil {
return nil, err
}
var res [][]byte
done:
for {
msgs, err := s.Receive()
if err != nil {
return nil, err
}
for _, m := range msgs {
if m.Header.Seq != req.Seq {
if sharedSocket {
continue
}
return nil, fmt.Errorf("Wrong Seq nr %d, expected %d", m.Header.Seq, req.Seq)
}
if m.Header.Pid != pid {
return nil, fmt.Errorf("Wrong pid %d, expected %d", m.Header.Pid, pid)
}
if m.Header.Type == syscall.NLMSG_DONE {
break done
}
if m.Header.Type == syscall.NLMSG_ERROR {
native := NativeEndian()
error := int32(native.Uint32(m.Data[0:4]))
if error == 0 {
break done
}
return nil, syscall.Errno(-error)
}
if resType != 0 && m.Header.Type != resType {
continue
}
res = append(res, m.Data)
if m.Header.Flags&syscall.NLM_F_MULTI == 0 {
break done
}
}
}
return res, nil
}
// Create a new netlink request from proto and flags
// Note the Len value will be inaccurate once data is added until
// the message is serialized
func NewNetlinkRequest(proto, flags int) *NetlinkRequest {
return &NetlinkRequest{
NlMsghdr: syscall.NlMsghdr{
Len: uint32(syscall.SizeofNlMsghdr),
Type: uint16(proto),
Flags: syscall.NLM_F_REQUEST | uint16(flags),
Seq: atomic.AddUint32(&nextSeqNr, 1),
},
}
}
type NetlinkSocket struct {
fd int
lsa syscall.SockaddrNetlink
sync.Mutex
}
func getNetlinkSocket(protocol int) (*NetlinkSocket, error) {
fd, err := syscall.Socket(syscall.AF_NETLINK, syscall.SOCK_RAW|syscall.SOCK_CLOEXEC, protocol)
if err != nil {
return nil, err
}
s := &NetlinkSocket{
fd: fd,
}
s.lsa.Family = syscall.AF_NETLINK
if err := syscall.Bind(fd, &s.lsa); err != nil {
syscall.Close(fd)
return nil, err
}
return s, nil
}
// GetNetlinkSocketAt opens a netlink socket in the network namespace newNs
// and positions the thread back into the network namespace specified by curNs,
// when done. If curNs is close, the function derives the current namespace and
// moves back into it when done. If newNs is close, the socket will be opened
// in the current network namespace.
func GetNetlinkSocketAt(newNs, curNs netns.NsHandle, protocol int) (*NetlinkSocket, error) {
c, err := executeInNetns(newNs, curNs)
if err != nil {
return nil, err
}
defer c()
return getNetlinkSocket(protocol)
}
// executeInNetns sets execution of the code following this call to the
// network namespace newNs, then moves the thread back to curNs if open,
// otherwise to the current netns at the time the function was invoked
// In case of success, the caller is expected to execute the returned function
// at the end of the code that needs to be executed in the network namespace.
// Example:
// func jobAt(...) error {
// d, err := executeInNetns(...)
// if err != nil { return err}
// defer d()
// < code which needs to be executed in specific netns>
// }
// TODO: his function probably belongs to netns pkg.
func executeInNetns(newNs, curNs netns.NsHandle) (func(), error) {
var (
err error
moveBack func(netns.NsHandle) error
closeNs func() error
unlockThd func()
)
restore := func() {
// order matters
if moveBack != nil {
moveBack(curNs)
}
if closeNs != nil {
closeNs()
}
if unlockThd != nil {
unlockThd()
}
}
if newNs.IsOpen() {
runtime.LockOSThread()
unlockThd = runtime.UnlockOSThread
if !curNs.IsOpen() {
if curNs, err = netns.Get(); err != nil {
restore()
return nil, fmt.Errorf("could not get current namespace while creating netlink socket: %v", err)
}
closeNs = curNs.Close
}
if err := netns.Set(newNs); err != nil {
restore()
return nil, fmt.Errorf("failed to set into network namespace %d while creating netlink socket: %v", newNs, err)
}
moveBack = netns.Set
}
return restore, nil
}
// Create a netlink socket with a given protocol (e.g. NETLINK_ROUTE)
// and subscribe it to multicast groups passed in variable argument list.
// Returns the netlink socket on which Receive() method can be called
// to retrieve the messages from the kernel.
func Subscribe(protocol int, groups ...uint) (*NetlinkSocket, error) {
fd, err := syscall.Socket(syscall.AF_NETLINK, syscall.SOCK_RAW, protocol)
if err != nil {
return nil, err
}
s := &NetlinkSocket{
fd: fd,
}
s.lsa.Family = syscall.AF_NETLINK
for _, g := range groups {
s.lsa.Groups |= (1 << (g - 1))
}
if err := syscall.Bind(fd, &s.lsa); err != nil {
syscall.Close(fd)
return nil, err
}
return s, nil
}
// SubscribeAt works like Subscribe plus let's the caller choose the network
// namespace in which the socket would be opened (newNs). Then control goes back
// to curNs if open, otherwise to the netns at the time this function was called.
func SubscribeAt(newNs, curNs netns.NsHandle, protocol int, groups ...uint) (*NetlinkSocket, error) {
c, err := executeInNetns(newNs, curNs)
if err != nil {
return nil, err
}
defer c()
return Subscribe(protocol, groups...)
}
func (s *NetlinkSocket) Close() {
syscall.Close(s.fd)
s.fd = -1
}
func (s *NetlinkSocket) GetFd() int {
return s.fd
}
func (s *NetlinkSocket) Send(request *NetlinkRequest) error {
if s.fd < 0 {
return fmt.Errorf("Send called on a closed socket")
}
if err := syscall.Sendto(s.fd, request.Serialize(), 0, &s.lsa); err != nil {
return err
}
return nil
}
func (s *NetlinkSocket) Receive() ([]syscall.NetlinkMessage, error) {
if s.fd < 0 {
return nil, fmt.Errorf("Receive called on a closed socket")
}
rb := make([]byte, syscall.Getpagesize())
nr, _, err := syscall.Recvfrom(s.fd, rb, 0)
if err != nil {
return nil, err
}
if nr < syscall.NLMSG_HDRLEN {
return nil, fmt.Errorf("Got short response from netlink")
}
rb = rb[:nr]
return syscall.ParseNetlinkMessage(rb)
}
func (s *NetlinkSocket) GetPid() (uint32, error) {
lsa, err := syscall.Getsockname(s.fd)
if err != nil {
return 0, err
}
switch v := lsa.(type) {
case *syscall.SockaddrNetlink:
return v.Pid, nil
}
return 0, fmt.Errorf("Wrong socket type")
}
func ZeroTerminated(s string) []byte {
bytes := make([]byte, len(s)+1)
for i := 0; i < len(s); i++ {
bytes[i] = s[i]
}
bytes[len(s)] = 0
return bytes
}
func NonZeroTerminated(s string) []byte {
bytes := make([]byte, len(s))
for i := 0; i < len(s); i++ {
bytes[i] = s[i]
}
return bytes
}
func BytesToString(b []byte) string {
n := bytes.Index(b, []byte{0})
return string(b[:n])
}
func Uint8Attr(v uint8) []byte {
return []byte{byte(v)}
}
func Uint16Attr(v uint16) []byte {
native := NativeEndian()
bytes := make([]byte, 2)
native.PutUint16(bytes, v)
return bytes
}
func Uint32Attr(v uint32) []byte {
native := NativeEndian()
bytes := make([]byte, 4)
native.PutUint32(bytes, v)
return bytes
}
func Uint64Attr(v uint64) []byte {
native := NativeEndian()
bytes := make([]byte, 8)
native.PutUint64(bytes, v)
return bytes
}
func ParseRouteAttr(b []byte) ([]syscall.NetlinkRouteAttr, error) {
var attrs []syscall.NetlinkRouteAttr
for len(b) >= syscall.SizeofRtAttr {
a, vbuf, alen, err := netlinkRouteAttrAndValue(b)
if err != nil {
return nil, err
}
ra := syscall.NetlinkRouteAttr{Attr: *a, Value: vbuf[:int(a.Len)-syscall.SizeofRtAttr]}
attrs = append(attrs, ra)
b = b[alen:]
}
return attrs, nil
}
func netlinkRouteAttrAndValue(b []byte) (*syscall.RtAttr, []byte, int, error) {
a := (*syscall.RtAttr)(unsafe.Pointer(&b[0]))
if int(a.Len) < syscall.SizeofRtAttr || int(a.Len) > len(b) {
return nil, nil, 0, syscall.EINVAL
}
return a, b[syscall.SizeofRtAttr:], rtaAlignOf(int(a.Len)), nil
}
// SocketHandle contains the netlink socket and the associated
// sequence counter for a specific netlink family
type SocketHandle struct {
Seq uint32
Socket *NetlinkSocket
}
// Close closes the netlink socket
func (sh *SocketHandle) Close() {
if sh.Socket != nil {
sh.Socket.Close()
}
}
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