func main() {
sk := nlgo.NlSocketAlloc()
if err := nlgo.GenlConnect(sk); err != nil {
panic(err)
} else if err := nlgo.GenlSendSimple(sk, nlgo.GENL_ID_CTRL, nlgo.CTRL_CMD_GETFAMILY, nlgo.CTRL_VERSION, syscall.NLM_F_DUMP); err != nil {
panic(err)
}
nl80211 := nlgo.NlSocketAlloc()
if err := nlgo.GenlConnect(nl80211); err != nil {
panic(err)
}
data := make([]byte, syscall.Getpagesize())
if n, _, _, _, err := syscall.Recvmsg(sk.Fd, data, nil, 0); err != nil {
panic(err)
} else if msgs, err := syscall.ParseNetlinkMessage(data[:n]); err != nil {
log.Print("X", err)
} else {
for _, msg := range msgs {
genl := *(*nlgo.GenlMsghdr)(unsafe.Pointer(&msg.Data[0]))
if msg.Header.Type == nlgo.GENL_ID_CTRL && genl.Cmd == nlgo.CTRL_CMD_NEWFAMILY {
if attr, err := nlgo.CtrlPolicy.Parse(msg.Data[nlgo.GENL_HDRLEN:]); err != nil {
log.Print(err)
} else if amap, ok := attr.(nlgo.AttrMap); !ok {
log.Print(attr)
} else if value := amap.Get(nlgo.CTRL_ATTR_FAMILY_NAME).(nlgo.NulString); string(value) == "nl80211" {
log.Printf("%v", attr)
for _, g := range amap.Get(nlgo.CTRL_ATTR_MCAST_GROUPS).(nlgo.AttrSlice).Slice() {
group := g.Value.(nlgo.AttrMap)
pid := group.Get(nlgo.CTRL_ATTR_MCAST_GRP_ID).(nlgo.U32)
if err := nlgo.NlSocketAddMembership(nl80211, int(pid)); err != nil {
log.Print(err)
}
}
}
} else {
log.Print("UNKNOWN")
}
}
}
nlgo.NlSocketFree(sk)
for {
if n, _, _, _, err := syscall.Recvmsg(nl80211.Fd, data, nil, 0); err != nil {
panic(err)
} else if msgs, err := syscall.ParseNetlinkMessage(data[:n]); err != nil {
log.Print("Y", err)
} else {
for _, msg := range msgs {
genl := (*nlgo.GenlMsghdr)(unsafe.Pointer(&msg.Data[0]))
if attr, err := nlgo.Nl80211Policy.Parse(msg.Data[nlgo.GENL_HDRLEN:]); err != nil {
log.Print("Z", err)
} else {
log.Printf("NL80211_CMD_%s attrs=%s", nlgo.NL80211_CMD_itoa[genl.Cmd], attr)
}
}
}
}
}
func getDefaultRoute() (*syscall.NetlinkMessage, error) {
dat, err := syscall.NetlinkRIB(syscall.RTM_GETROUTE, syscall.AF_UNSPEC)
if err != nil {
return nil, err
}
msgs, msgErr := syscall.ParseNetlinkMessage(dat)
if msgErr != nil {
return nil, msgErr
}
rtmsg := syscall.RtMsg{}
for _, m := range msgs {
if m.Header.Type != syscall.RTM_NEWROUTE {
continue
}
buf := bytes.NewBuffer(m.Data[:syscall.SizeofRtMsg])
if rerr := binary.Read(buf, binary.LittleEndian, &rtmsg); rerr != nil {
continue
}
if rtmsg.Dst_len == 0 {
// zero-length Dst_len implies default route
return &m, nil
}
}
return nil, errNoDefaultRoute
}
func TestParseNetlinkMessage(t *testing.T) {
for i, b := range [][]byte{
{103, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 2, 11, 0, 1, 0, 0, 0, 0, 5, 8, 0, 3,
0, 8, 0, 6, 0, 0, 0, 0, 1, 63, 0, 10, 0, 69, 16, 0, 59, 39, 82, 64, 0, 64, 6, 21, 89, 127, 0, 0,
1, 127, 0, 0, 1, 230, 228, 31, 144, 32, 186, 155, 211, 185, 151, 209, 179, 128, 24, 1, 86,
53, 119, 0, 0, 1, 1, 8, 10, 0, 17, 234, 12, 0, 17, 189, 126, 107, 106, 108, 107, 106, 13, 10,
},
{106, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 2, 11, 0, 1, 0, 0, 0, 0, 3, 8, 0, 3,
0, 8, 0, 6, 0, 0, 0, 0, 1, 66, 0, 10, 0, 69, 0, 0, 62, 230, 255, 64, 0, 64, 6, 85, 184, 127, 0, 0,
1, 127, 0, 0, 1, 237, 206, 31, 144, 73, 197, 128, 65, 250, 60, 192, 97, 128, 24, 1, 86, 253, 21, 0,
0, 1, 1, 8, 10, 0, 51, 106, 89, 0, 51, 102, 198, 108, 104, 106, 108, 107, 104, 108, 107, 104, 10,
},
{102, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 2, 11, 0, 1, 0, 0, 0, 0, 1, 8, 0, 3, 0,
8, 0, 6, 0, 0, 0, 0, 1, 62, 0, 10, 0, 69, 0, 0, 58, 231, 2, 64, 0, 64, 6, 85, 185, 127, 0, 0, 1, 127,
0, 0, 1, 237, 206, 31, 144, 73, 197, 128, 86, 250, 60, 192, 97, 128, 24, 1, 86, 104, 64, 0, 0, 1, 1, 8,
10, 0, 52, 198, 200, 0, 51, 135, 232, 101, 115, 97, 103, 103, 10,
},
} {
m, err := syscall.ParseNetlinkMessage(b)
if err != syscall.EINVAL {
t.Errorf("#%d: got %v; want EINVAL", i, err)
}
if m != nil {
t.Errorf("#%d: got %v; want nil", i, m)
}
}
}
// getNeighbors sends a request to netlink to retrieve all neighbors using
// the specified address family.
func getNeighbors(family Family) ([]*Neighbor, error) {
// Request neighbors belonging to a specific family from netlink
tab, err := syscall.NetlinkRIB(syscall.RTM_GETNEIGH, int(family))
if err != nil {
return nil, os.NewSyscallError("netlink rib", err)
}
// Parse netlink information into individual messages
msgs, err := syscall.ParseNetlinkMessage(tab)
if err != nil {
return nil, os.NewSyscallError("netlink message", err)
}
// Check messages for information
var nn []*Neighbor
for _, m := range msgs {
// Ignore any messages which don't indicate a new neighbor
if m.Header.Type != syscall.RTM_NEWNEIGH {
continue
}
// Attempt to parse an individual neighbor from a message
n, err := newNeighbor(&m)
if err != nil {
return nil, err
}
nn = append(nn, n)
}
return nn, nil
}
func getIface(idx uint32) (*syscall.NetlinkMessage, error) {
dat, err := syscall.NetlinkRIB(syscall.RTM_GETADDR, syscall.AF_UNSPEC)
if err != nil {
return nil, err
}
msgs, msgErr := syscall.ParseNetlinkMessage(dat)
if msgErr != nil {
return nil, msgErr
}
ifaddrmsg := syscall.IfAddrmsg{}
for _, m := range msgs {
if m.Header.Type != syscall.RTM_NEWADDR {
continue
}
buf := bytes.NewBuffer(m.Data[:syscall.SizeofIfAddrmsg])
if rerr := binary.Read(buf, binary.LittleEndian, &ifaddrmsg); rerr != nil {
continue
}
if ifaddrmsg.Index == idx {
return &m, nil
}
}
return nil, errNoDefaultRoute
}
// If the ifindex is zero, interfaceTable returns mappings of all
// network interfaces. Otherwise it returns a mapping of a specific
// interface.
func interfaceTable(ifindex int) ([]Interface, error) { // 如果ifindex为0，返回所有网络接口
tab, err := syscall.NetlinkRIB(syscall.RTM_GETLINK, syscall.AF_UNSPEC) // 获得netlink rib
if err != nil {
return nil, os.NewSyscallError("netlinkrib", err)
}
msgs, err := syscall.ParseNetlinkMessage(tab) // 解析netlink信息
if err != nil {
return nil, os.NewSyscallError("parsenetlinkmessage", err)
}
var ift []Interface
loop:
for _, m := range msgs { // 遍历获取的netlink信息
switch m.Header.Type {
case syscall.NLMSG_DONE:
break loop
case syscall.RTM_NEWLINK:
ifim := (*syscall.IfInfomsg)(unsafe.Pointer(&m.Data[0]))
if ifindex == 0 || ifindex == int(ifim.Index) {
attrs, err := syscall.ParseNetlinkRouteAttr(&m)
if err != nil {
return nil, os.NewSyscallError("parsenetlinkrouteattr", err)
}
ift = append(ift, *newLink(ifim, attrs)) // 加入到Interface Slice中
if ifindex == int(ifim.Index) {
break loop
}
}
}
}
return ift, nil
}
// If the ifindex is zero, interfaceTable returns mappings of all
// network interfaces. Otheriwse it returns a mapping of a specific
// interface.
func interfaceTable(ifindex int) ([]Interface, error) {
tab, err := syscall.NetlinkRIB(syscall.RTM_GETLINK, syscall.AF_UNSPEC)
if err != nil {
return nil, os.NewSyscallError("netlink rib", err)
}
msgs, err := syscall.ParseNetlinkMessage(tab)
if err != nil {
return nil, os.NewSyscallError("netlink message", err)
}
var ift []Interface
for _, m := range msgs {
switch m.Header.Type {
case syscall.NLMSG_DONE:
goto done
case syscall.RTM_NEWLINK:
ifim := (*syscall.IfInfomsg)(unsafe.Pointer(&m.Data[0]))
if ifindex == 0 || ifindex == int(ifim.Index) {
attrs, err := syscall.ParseNetlinkRouteAttr(&m)
if err != nil {
return nil, os.NewSyscallError("netlink routeattr", err)
}
ifi := newLink(ifim, attrs)
ift = append(ift, ifi)
}
}
}
done:
return ift, nil
}
func (w *Watcher) readAllEvents() {
buf := make([]byte, syscall.Getpagesize())
listener, _ := w.listener.(*netlinkListener)
for {
if w.isDone() {
return
}
nr, _, err := syscall.Recvfrom(listener.sock, buf, 0)
if err != nil {
w.Error <- err
continue
}
if nr < syscall.NLMSG_HDRLEN {
w.Error <- syscall.EINVAL
continue
}
msgs, _ := syscall.ParseNetlinkMessage(buf[:nr])
for _, m := range msgs {
if m.Header.Type == syscall.NLMSG_DONE {
w.handleEventAll(m.Data)
}
}
}
}
// If the ifindex is zero, interfaceAddrTable returns addresses
// for all network interfaces. Otherwise it returns addresses
// for a specific interface.
func interfaceAddrTable(ifindex int) ([]Addr, os.Error) {
var (
tab []byte
e int
err os.Error
ifat []Addr
msgs []syscall.NetlinkMessage
)
tab, e = syscall.NetlinkRIB(syscall.RTM_GETADDR, syscall.AF_UNSPEC)
if e != 0 {
return nil, os.NewSyscallError("netlink rib", e)
}
msgs, e = syscall.ParseNetlinkMessage(tab)
if e != 0 {
return nil, os.NewSyscallError("netlink message", e)
}
ifat, err = addrTable(msgs, ifindex)
if err != nil {
return nil, err
}
return ifat, nil
}
func (nl *NetlinkSocket) RecvMessages(sz, sockflags int) ([]NetlinkMessage, error) {
buf := make([]byte, sz)
rsz, _, err := syscall.Recvfrom(nl.sfd, buf, sockflags)
if err != nil {
return nil, err
}
if rsz < syscall.NLMSG_HDRLEN {
return nil, syscall.EINVAL
}
msgList, err := syscall.ParseNetlinkMessage(buf[:rsz])
if err != nil {
return nil, err
}
ret := []NetlinkMessage{}
for _, msg := range msgList {
msg := NetlinkMessage(msg)
logf("received: %+v\n", msg)
ret = append(ret, msg)
}
return ret, nil
}
func TestSocketPacketConn(t *testing.T) {
s, err := syscall.Socket(syscall.AF_NETLINK, syscall.SOCK_RAW, syscall.NETLINK_ROUTE)
if err != nil {
t.Fatal(err)
}
lsa := syscall.SockaddrNetlink{Family: syscall.AF_NETLINK}
if err := syscall.Bind(s, &lsa); err != nil {
syscall.Close(s)
t.Fatal(err)
}
f := os.NewFile(uintptr(s), "netlink")
c, err := SocketPacketConn(f, &netlinkAddr{})
f.Close()
if err != nil {
t.Fatal(err)
}
defer c.Close()
const N = 3
var wg sync.WaitGroup
wg.Add(2 * N)
dst := &netlinkAddr{PID: 0}
for i := 0; i < N; i++ {
go func() {
defer wg.Done()
l := syscall.NLMSG_HDRLEN + syscall.SizeofRtGenmsg
b := make([]byte, l)
*(*uint32)(unsafe.Pointer(&b[0:4][0])) = uint32(l)
*(*uint16)(unsafe.Pointer(&b[4:6][0])) = uint16(syscall.RTM_GETLINK)
*(*uint16)(unsafe.Pointer(&b[6:8][0])) = uint16(syscall.NLM_F_DUMP | syscall.NLM_F_REQUEST)
*(*uint32)(unsafe.Pointer(&b[8:12][0])) = uint32(1)
*(*uint32)(unsafe.Pointer(&b[12:16][0])) = uint32(0)
b[16] = byte(syscall.AF_UNSPEC)
if _, err := c.WriteTo(b, dst); err != nil {
t.Error(err)
return
}
}()
}
for i := 0; i < N; i++ {
go func() {
defer wg.Done()
b := make([]byte, os.Getpagesize())
n, _, err := c.ReadFrom(b)
if err != nil {
t.Error(err)
return
}
if _, err := syscall.ParseNetlinkMessage(b[:n]); err != nil {
t.Error(err)
return
}
}()
}
wg.Wait()
}
func NewRtHub() (*RtHub, error) {
self := &RtHub{
sock: NlSocketAlloc(),
lock: &sync.Mutex{},
unilock: &sync.Mutex{},
multicast: make(map[uint32][]NetlinkListener),
}
if err := NlConnect(self.sock, syscall.NETLINK_ROUTE); err != nil {
NlSocketFree(self.sock)
return nil, err
}
go func() {
for {
buf := make([]byte, syscall.Getpagesize())
if n, _, err := syscall.Recvfrom(self.sock.Fd, buf, syscall.MSG_TRUNC); err != nil {
if e, ok := err.(syscall.Errno); ok && e.Temporary() {
continue
}
break
} else if msgs, err := syscall.ParseNetlinkMessage(buf[:n]); err != nil {
break
} else {
for _, msg := range msgs {
multi := func() []NetlinkListener {
self.lock.Lock()
defer self.lock.Unlock()
var ret []NetlinkListener
for _, s := range self.multicast {
ret = append(ret, s...)
}
return ret
}()
if msg.Header.Seq == self.uniseq {
if self.unicast != nil {
self.unicast.NetlinkListen(msg)
}
switch msg.Header.Type {
case syscall.NLMSG_DONE, syscall.NLMSG_ERROR:
self.unilock.Unlock()
}
}
if msg.Header.Seq == 0 {
for _, proc := range multi {
proc.NetlinkListen(msg)
}
}
}
}
}
log.Print("rt hub loop exit")
}()
return self, nil
}
func (s *NetlinkSocket) Receive() ([]syscall.NetlinkMessage, error) {
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, ErrShortResponse
}
rb = rb[:nr]
return syscall.ParseNetlinkMessage(rb)
}
// If the ifindex is zero, interfaceAddrTable returns addresses
// for all network interfaces. Otherwise it returns addresses
// for a specific interface.
func interfaceAddrTable(ifindex int) ([]Addr, os.Error) {
var (
tab []byte
e int
err os.Error
ifat4 []Addr
ifat6 []Addr
msgs4 []syscall.NetlinkMessage
msgs6 []syscall.NetlinkMessage
)
tab, e = syscall.NetlinkRIB(syscall.RTM_GETADDR, syscall.AF_INET)
if e != 0 {
return nil, os.NewSyscallError("netlink rib", e)
}
msgs4, e = syscall.ParseNetlinkMessage(tab)
if e != 0 {
return nil, os.NewSyscallError("netlink message", e)
}
ifat4, err = addrTable(msgs4, ifindex)
if err != nil {
return nil, err
}
tab, e = syscall.NetlinkRIB(syscall.RTM_GETADDR, syscall.AF_INET6)
if e != 0 {
return nil, os.NewSyscallError("netlink rib", e)
}
msgs6, e = syscall.ParseNetlinkMessage(tab)
if e != 0 {
return nil, os.NewSyscallError("netlink message", e)
}
ifat6, err = addrTable(msgs6, ifindex)
if err != nil {
return nil, err
}
return append(ifat4, ifat6...), nil
}
// genl_ctrl_probe_by_name is not exposed in the original libnl
func GenlCtrlProbeByName(sk *NlSock, name string) (AttrMap, error) {
if err := GenlSendSimple(sk, GENL_ID_CTRL, CTRL_CMD_GETFAMILY, CTRL_VERSION, syscall.NLM_F_DUMP); err != nil {
return AttrMap{}, err
}
var ret AttrMap
err := func() error {
for {
buf := make([]byte, syscall.Getpagesize())
if nn, _, err := syscall.Recvfrom(sk.Fd, buf, syscall.MSG_TRUNC); err != nil {
return err
} else if nn > len(buf) {
return NLE_MSG_TRUNC
} else {
buf = buf[:nn]
}
if msgs, err := syscall.ParseNetlinkMessage(buf); err != nil {
return err
} else {
for _, msg := range msgs {
switch msg.Header.Type {
case GENL_ID_CTRL:
genl := (*GenlMsghdr)(unsafe.Pointer(&msg.Data[0]))
switch genl.Cmd {
case CTRL_CMD_NEWFAMILY:
if attrs, err := CtrlPolicy.Parse(msg.Data[GENL_HDRLEN:]); err != nil {
return err
} else if info, ok := attrs.(AttrMap); !ok {
// shold not happen
} else if value := info.Get(CTRL_ATTR_FAMILY_NAME); value == nil {
// should not happen by kernel
} else if string(value.(NulString)) == name {
ret = info
}
default:
return fmt.Errorf("unexpected command")
}
case syscall.NLMSG_DONE:
return nil
case syscall.NLMSG_ERROR:
return fmt.Errorf("NlMsgerr=%s", (*syscall.NlMsgerr)(unsafe.Pointer(&msg.Data[0])))
default:
return fmt.Errorf("unexpected NlMsghdr=%s", msg.Header)
}
}
}
}
}()
return ret, err
}
// Receive receives one or more Messages from netlink.
func (c *conn) Receive() ([]Message, error) {
b := make([]byte, os.Getpagesize())
for {
// Peek at the buffer to see how many bytes are available
n, _, err := c.s.Recvfrom(b, syscall.MSG_PEEK)
if err != nil {
return nil, err
}
// Break when we can read all messages
if n < len(b) {
break
}
// Double in size if not enough bytes
b = make([]byte, len(b)*2)
}
// Read out all available messages
n, from, err := c.s.Recvfrom(b, 0)
if err != nil {
return nil, err
}
addr, ok := from.(*syscall.SockaddrNetlink)
if !ok {
return nil, errInvalidSockaddr
}
if addr.Family != syscall.AF_NETLINK {
return nil, errInvalidFamily
}
raw, err := syscall.ParseNetlinkMessage(b[:n])
if err != nil {
return nil, err
}
msgs := make([]Message, 0, len(raw))
for _, r := range raw {
m := Message{
Header: sysToHeader(r.Header),
Data: r.Data,
}
msgs = append(msgs, m)
}
return msgs, nil
}
// If the ifindex is zero, interfaceAddrTable returns addresses
// for all network interfaces. Otherwise it returns addresses
// for a specific interface.
func interfaceAddrTable(ifindex int) ([]Addr, error) {
tab, err := syscall.NetlinkRIB(syscall.RTM_GETADDR, syscall.AF_UNSPEC)
if err != nil {
return nil, os.NewSyscallError("netlink rib", err)
}
msgs, err := syscall.ParseNetlinkMessage(tab)
if err != nil {
return nil, os.NewSyscallError("netlink message", err)
}
ifat, err := addrTable(msgs, ifindex)
if err != nil {
return nil, err
}
return ifat, 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)
}
// This basic rtnetlink example lists up link interfaces.
func Example() {
sock := NlSocketAlloc()
defer NlSocketFree(sock)
if err := NlConnect(sock, syscall.NETLINK_ROUTE); err != nil {
panic(err)
}
req := make([]byte, NLMSG_ALIGN(syscall.SizeofIfInfomsg))
if err := NlSendSimple(sock, syscall.RTM_GETLINK, syscall.NLM_F_DUMP, req); err != nil {
panic(err)
}
func() {
for {
buf := make([]byte, syscall.Getpagesize())
if nn, _, err := syscall.Recvfrom(sock.Fd, buf, syscall.MSG_TRUNC); err != nil {
panic(err)
} else if nn > len(buf) {
panic("out of recv buf")
} else {
buf = buf[:nn]
}
if msgs, err := syscall.ParseNetlinkMessage(buf); err != nil {
panic(err)
} else {
for _, msg := range msgs {
switch msg.Header.Type {
case syscall.RTM_NEWLINK:
ifinfo := (*syscall.IfInfomsg)(unsafe.Pointer(&msg.Data[0]))
if attrs, err := RouteLinkPolicy.Parse(msg.Data[NLA_ALIGN(syscall.SizeofIfInfomsg):]); err != nil {
panic(err)
} else {
log.Print("ifinfomsg=", ifinfo, " attrs=", attrs)
}
case syscall.NLMSG_DONE:
return
default:
log.Print("unhandled msg", msg.Header)
}
}
}
}
}()
}
// If the ifi is nil, interfaceAddrTable returns addresses for all
// network interfaces. Otherwise it returns addresses for a specific
// interface.
func interfaceAddrTable(ifi *Interface) ([]Addr, error) {
tab, err := syscall.NetlinkRIB(syscall.RTM_GETADDR, syscall.AF_UNSPEC)
if err != nil {
return nil, os.NewSyscallError("netlinkrib", err)
}
msgs, err := syscall.ParseNetlinkMessage(tab)
if err != nil {
return nil, os.NewSyscallError("parsenetlinkmessage", err)
}
var ift []Interface
if ifi == nil {
var err error
ift, err = interfaceTable(0)
if err != nil {
return nil, err
}
}
ifat, err := addrTable(ift, ifi, msgs)
if err != nil {
return nil, err
}
return ifat, nil
}
func find_gateway(ip_mask *net.IPNet) (ip net.IP, dev string, err error) {
buf, err := syscall.NetlinkRIB(syscall.RTM_GETROUTE, syscall.AF_INET)
if err != nil {
log.Println("Failed to open netlink:", err)
return
}
msgs, err := syscall.ParseNetlinkMessage(buf)
if err != nil {
log.Println("Failed to parse nl msg:", err)
return
}
var def route
set := false
var once sync.Once
loop:
for _, m := range msgs {
switch m.Header.Type {
case syscall.NLMSG_DONE:
break loop
case syscall.RTM_NEWROUTE:
// a route enrty
var r route
rtmsg := (*syscall.RtMsg)(unsafe.Pointer(&m.Data[0]))
attrs, err := syscall.ParseNetlinkRouteAttr(&m)
if err != nil {
// err is shadowed
log.Println("Failed to parse nl rtattr:", err)
return ip, dev, err
}
// parse a route entry
for _, a := range attrs {
switch a.Attr.Type {
case syscall.RTA_DST:
addr := a.Value
_, r.dst, err = net.ParseCIDR(fmt.Sprintf("%d.%d.%d.%d/%d", addr[0], addr[1], addr[2], addr[3], rtmsg.Dst_len))
if err != nil {
log.Println("Failed to parse ip addr:", err)
return ip, dev, err
}
case syscall.RTA_GATEWAY:
addr := a.Value
r.gateway = net.IPv4(addr[0], addr[1], addr[2], addr[3])
case syscall.RTA_OIF:
r.if_index = int(a.Value[0])
}
}
if r.dst == nil {
once.Do(func() {
def = r
set = true
})
} else {
if r.dst.Contains(ip_mask.IP) {
ifce, err := net.InterfaceByIndex(r.if_index)
if err != nil {
log.Println("Failed to get interface by index:", err)
return ip, dev, err
}
return r.gateway, ifce.Name, nil
}
}
}
}
if set {
ifce, err := net.InterfaceByIndex(def.if_index)
if err != nil {
log.Println("Failed to get interface by index:", err)
return ip, dev, err
}
return def.gateway, ifce.Name, nil
}
err = fmt.Errorf("Route not found.")
return
}
// New creates a new router object. The router returned by New currently does
// not update its routes after construction... care should be taken for
// long-running programs to call New() regularly to take into account any
// changes to the routing table which have occurred since the last New() call.
func New() (Router, error) {
rtr := &router{}
tab, err := syscall.NetlinkRIB(syscall.RTM_GETROUTE, syscall.AF_UNSPEC)
if err != nil {
return nil, err
}
msgs, err := syscall.ParseNetlinkMessage(tab)
if err != nil {
return nil, err
}
loop:
for _, m := range msgs {
switch m.Header.Type {
case syscall.NLMSG_DONE:
break loop
case syscall.RTM_NEWROUTE:
rt := (*routeInfoInMemory)(unsafe.Pointer(&m.Data[0]))
routeInfo := rtInfo{}
attrs, err := syscall.ParseNetlinkRouteAttr(&m)
if err != nil {
return nil, err
}
switch rt.Family {
case syscall.AF_INET:
rtr.v4 = append(rtr.v4, &routeInfo)
case syscall.AF_INET6:
rtr.v6 = append(rtr.v6, &routeInfo)
default:
continue loop
}
for _, attr := range attrs {
switch attr.Attr.Type {
case syscall.RTA_DST:
routeInfo.Dst = &net.IPNet{
IP: net.IP(attr.Value),
Mask: net.CIDRMask(int(rt.DstLen), len(attr.Value)*8),
}
case syscall.RTA_SRC:
routeInfo.Src = &net.IPNet{
IP: net.IP(attr.Value),
Mask: net.CIDRMask(int(rt.SrcLen), len(attr.Value)*8),
}
case syscall.RTA_GATEWAY:
routeInfo.Gateway = net.IP(attr.Value)
case syscall.RTA_PREFSRC:
routeInfo.PrefSrc = net.IP(attr.Value)
case syscall.RTA_IIF:
routeInfo.InputIface = *(*uint32)(unsafe.Pointer(&attr.Value[0]))
case syscall.RTA_OIF:
routeInfo.OutputIface = *(*uint32)(unsafe.Pointer(&attr.Value[0]))
case syscall.RTA_PRIORITY:
routeInfo.Priority = *(*uint32)(unsafe.Pointer(&attr.Value[0]))
}
}
}
}
sort.Sort(rtr.v4)
sort.Sort(rtr.v6)
ifaces, err := net.Interfaces()
if err != nil {
return nil, err
}
for i, iface := range ifaces {
if i != iface.Index-1 {
return nil, fmt.Errorf("out of order iface %d = %v", i, iface)
}
rtr.ifaces = append(rtr.ifaces, iface)
var addrs ipAddrs
ifaceAddrs, err := iface.Addrs()
if err != nil {
return nil, err
}
for _, addr := range ifaceAddrs {
if inet, ok := addr.(*net.IPNet); ok {
// Go has a nasty habit of giving you IPv4s as ::ffff:1.2.3.4 instead of 1.2.3.4.
// We want to use mapped v4 addresses as v4 preferred addresses, never as v6
// preferred addresses.
if v4 := inet.IP.To4(); v4 != nil {
if addrs.v4 == nil {
addrs.v4 = v4
}
} else if addrs.v6 == nil {
addrs.v6 = inet.IP
}
}
}
rtr.addrs = append(rtr.addrs, addrs)
}
return rtr, nil
}
func MonitorIP() {
// Create a Unix socket to listen for NetLink changes
fd, err := syscall.Socket(syscall.AF_NETLINK, syscall.SOCK_RAW, syscall.NETLINK_ROUTE)
if err != nil {
fmt.Println("Error creating unix socket:", err)
return
}
defer syscall.Close(fd)
// Netlink options
sn := syscall.SockaddrNetlink{
Pid: 0, // Pid 0 == KERNEL messages
Groups: syscall.RTNLGRP_LINK | syscall.RTNLGRP_IPV4_IFADDR, // Broadcast groups
}
// Bind to the Socket
err = syscall.Bind(fd, &sn)
if err != nil {
fmt.Println("Binding fd to socket failed")
}
// Infinite loop to keep listening for changes
buff := make([]byte, syscall.Getpagesize())
for {
n, _, err := syscall.Recvfrom(fd, buff, 0x00)
if err != nil {
fmt.Println("Error when receiving from the socket: ", err)
}
// Incorrect header length, ignore
if n < syscall.NLMSG_HDRLEN {
continue
}
msgs, err := syscall.ParseNetlinkMessage(buff[:n])
if err != nil {
fmt.Println("Parsing netlink message failed")
}
// Loop over parsed Netlink messages
for _, msg := range msgs {
if msg.Header.Type == syscall.NLMSG_ERROR {
fmt.Println("Netlink message error!")
continue
}
// Ignore multipart messages
if msg.Header.Type == syscall.NLMSG_DONE {
continue
}
// Ignore neighbor messages
if msg.Header.Type == syscall.RTM_DELNEIGH || msg.Header.Type == syscall.RTM_NEWNEIGH {
continue
}
fmt.Printf("RECEIVED : %+v \n", msg)
if msg.Header.Type == syscall.RTM_NEWLINK {
ifMsg := syscall.IfInfomsg{
Family: msg.Data[0], // AF_UNSPEC (always)
X__ifi_pad: msg.Data[1], // Reserved
Type: binary.LittleEndian.Uint16(msg.Data[2:4]),
Index: int32(binary.LittleEndian.Uint32(msg.Data[4:8])),
Flags: binary.LittleEndian.Uint32(msg.Data[8:12]),
Change: binary.LittleEndian.Uint32(msg.Data[12:16]), // Reserved for future use
}
// Check if the interface is "administratively" up
if ifMsg.Flags&syscall.IFF_UP == 0 {
continue
}
// Check if the interface is operationally up
if ifMsg.Flags&syscall.IFF_RUNNING == 0 {
continue
}
//nlAttrs, _ := syscall.ParseNetlinkRouteAttr(&msg)
iface, _ := net.InterfaceByIndex(int(ifMsg.Index))
addrs, _ := iface.Addrs()
//fmt.Printf("RTM_NEWLINK: %+v \n", ifMsg)
//fmt.Printf("RTM_NEWLINK ATTRIBUTES: %+v \n", nlAttrs)
//fmt.Printf("RTM_NEWLINK INTERFACE: %+v \n", iface)
fmt.Printf("RTM_NEWLINK INTERFACE ADDRS: %+v \n", addrs)
if len(addrs) > 0 {
fmt.Printf("%s is now available at %s \n", iface.Name, addrs[0].(*net.IPNet).IP)
} else {
fmt.Printf("No address associated yet with %s \n", iface.Name)
}
} else {
continue
}
}
}
}
func NewGenlHub() (*GenlHub, error) {
self := &GenlHub{
sock: NlSocketAlloc(),
lock: &sync.Mutex{},
familyIds: map[uint16]GenlFamily{
GENL_ID_CTRL: GenlFamilyCtrl,
},
groupIds: map[uint32]GenlGroup{
GENL_ID_CTRL: GenlGroup{
Id: GENL_ID_CTRL,
Family: "nlctrl",
Name: "notify",
},
},
unilock: &sync.Mutex{},
multicast: make(map[groupKey][]GenlListener),
}
if err := NlConnect(self.sock, syscall.NETLINK_GENERIC); err != nil {
self.Close()
return nil, err
}
if err := self.Add("nlctrl", "notify", self); err != nil {
self.Close()
return nil, err
}
if err := self.Async(GenlFamilyCtrl.DumpRequest(CTRL_CMD_GETFAMILY), self); err != nil {
self.Close()
return nil, err
}
go func() {
for {
buf := make([]byte, syscall.Getpagesize())
if bufN, _, err := syscall.Recvfrom(self.sock.Fd, buf, syscall.MSG_TRUNC); err != nil {
if e, ok := err.(syscall.Errno); ok && e.Temporary() {
continue
}
break
} else if msgs, err := syscall.ParseNetlinkMessage(buf[:bufN]); err != nil {
break
} else {
for _, msg := range msgs {
self.lock.Lock()
family := self.familyIds[msg.Header.Type]
var multi []GenlListener
for gkey, s := range self.multicast {
if family.Name == gkey.Family {
for _, n := range s {
if uniq := func() bool {
for _, m := range multi {
if m == n {
return false
}
}
return true
}(); uniq {
multi = append(multi, n)
}
}
}
}
self.lock.Unlock()
gmsg := GenlMessage{
NetlinkMessage: msg,
Family: family,
}
if msg.Header.Seq == self.uniseq {
if self.unicast != nil {
self.unicast.GenlListen(gmsg)
}
switch msg.Header.Type {
case syscall.NLMSG_DONE, syscall.NLMSG_ERROR:
self.unilock.Unlock()
}
}
if msg.Header.Seq == 0 {
for _, proc := range multi {
proc.GenlListen(gmsg)
}
}
}
}
}
log.Print("genl hub loop exit")
}()
return self, nil
}
func GetTaskStats(nlsk *nlgo.NlSock, p int) (t *Taskstats) {
nlsk.Flags |= nlgo.NL_NO_AUTO_ACK
const familyID = 22
m := &MSG{
Len: 8,
Type: TASKSTATS_CMD_ATTR_PID,
Pid: uint32(p),
}
hdr := (*[nlgo.SizeofGenlMsghdr]byte)(unsafe.Pointer(&nlgo.GenlMsghdr{
Cmd: TASKSTATS_CMD_GET,
Version: 0,
}))[:]
req := ((*[8]byte)(unsafe.Pointer(m)))[:]
length := 4
pad := ((length + 4 - 1) & (^3)) - length
for i := 0; i < pad; i++ {
req = append(req, 0)
}
hdr = append(hdr, req...)
nlgo.NlSendSimple(nlsk, familyID, 1, hdr[:])
func() error {
for {
buf := make([]byte, 16384)
if nn, _, err := syscall.Recvfrom(nlsk.Fd, buf, 0); err != nil {
return err
} else if nn > len(buf) {
return nlgo.NLE_MSG_TRUNC
} else {
buf = buf[:nn]
}
if msgs, err := syscall.ParseNetlinkMessage(buf); err != nil {
return err
} else {
for _, msg := range msgs {
switch msg.Header.Type {
case syscall.NLMSG_DONE:
return nil
case syscall.NLMSG_ERROR:
return fmt.Errorf("NlMsgerr=%s", nlgo.NlMsgerr(msg))
case 22:
genl := (*nlgo.GenlMsghdr)(unsafe.Pointer(&msg.Data[0]))
_ = genl
attrs := parse_attributes(msg.Data[nlgo.GENL_HDRLEN:])
for _, attr := range attrs {
if attr.Type == TASKSTATS_TYPE_AGGR_PID {
attrs = parse_attributes(attr.Data)
break
}
}
for _, attr := range attrs {
if attr.Type == TASKSTATS_TYPE_STATS {
_ = uint32(*(*uint32)(unsafe.Pointer(&attr.Data[248])))
t = (*Taskstats)(unsafe.Pointer(&attr.Data[0]))
break
}
}
return nil
default:
return fmt.Errorf("unexpected NlMsghdr=%s", msg.Header)
}
}
}
}
}()
// if err != nil {
// fmt.Println(err, err.Error())
// }
return
}
// List all available routes on the system.
func Routes() ([]*Route, error) {
var routes []*Route
rib, err := syscall.NetlinkRIB(syscall.RTM_GETROUTE, syscall.AF_UNSPEC)
if err != nil {
return nil, fmt.Errorf("Could not retrieve RIB: %s", err)
}
msgs, err := syscall.ParseNetlinkMessage(rib)
if err != nil {
return nil, fmt.Errorf("Could not parse messages: %s")
}
for _, m := range msgs {
if m.Header.Type == syscall.NLMSG_DONE {
break
}
if m.Header.Type != syscall.RTM_NEWROUTE {
continue
}
route := &Route{Default: true}
rtmsg := (*rtmsg)(unsafe.Pointer(&m.Data[0]))
attrs, err := syscall.ParseNetlinkRouteAttr(&m)
if err != nil {
return nil, fmt.Errorf("Could not parse attr: %s", err)
}
for _, a := range attrs {
switch a.Attr.Type {
case syscall.RTA_SRC:
route.SrcNet = &net.IPNet{
IP: net.IP(a.Value),
Mask: net.CIDRMask(
int(rtmsg.src_len),
len(a.Value)*8,
),
}
case syscall.RTA_DST:
route.DstNet = &net.IPNet{
IP: net.IP(a.Value),
Mask: net.CIDRMask(
int(rtmsg.dst_len),
len(a.Value)*8,
),
}
route.Default = false
case syscall.RTA_GATEWAY:
route.Gateway = net.IP(a.Value)
case syscall.RTA_OIF:
oif := *(*uint32)(unsafe.Pointer(&a.Value[0]))
iface, err := net.InterfaceByIndex(int(oif))
if err != nil {
}
route.Iface = iface
case syscall.RTA_PRIORITY:
}
}
routes = append(routes, route)
}
return routes, nil
}
func NewGenlHub() (*GenlHub, error) {
self := &GenlHub{
sock: NlSocketAlloc(),
lock: &sync.Mutex{},
familyIds: map[uint16]GenlFamily{
GENL_ID_CTRL: GenlFamily{
Id: GENL_ID_CTRL,
Name: "nlctrl",
Version: 1,
},
},
groupIds: map[uint32]GenlGroup{
GENL_ID_CTRL: GenlGroup{
Id: GENL_ID_CTRL,
Family: "nlctrl",
Name: "notify",
},
},
unicast: make(map[uint32]chan GenlMessage),
multicast: make(map[groupKey][]GenlListener),
}
if err := NlConnect(self.sock, syscall.NETLINK_GENERIC); err != nil {
NlSocketFree(self.sock)
return nil, err
}
go func() {
feed := func(msg GenlMessage) {
seq := msg.Header.Seq
if seq == 0 { // multicast
var listeners []GenlListener
self.lock.Lock()
if family, ok := self.familyIds[msg.Header.Type]; ok {
for gkey, ls := range self.multicast {
if gkey.Family == family.Name {
for _, listener := range ls {
if ok := func() bool { // remove duplicate
for _, li := range listeners {
if li == listener {
return false
}
}
return true
}(); ok {
listeners = append(listeners, listener)
}
}
}
}
} else {
log.Print("got unknown family message")
}
self.lock.Unlock()
for _, listener := range listeners {
listener.GenlListen(msg)
}
} else {
self.lock.Lock()
listener := self.unicast[seq]
self.lock.Unlock()
if listener != nil {
listener <- msg
mtype := msg.Header.Type
if mtype == syscall.NLMSG_DONE || mtype == syscall.NLMSG_ERROR { // NlSock.Flags NL_NO_AUTO_ACK is 0 by default
self.lock.Lock()
delete(self.unicast, seq)
self.lock.Unlock()
close(listener)
}
}
}
}
for {
buf := make([]byte, syscall.Getpagesize())
if bufN, _, err := syscall.Recvfrom(self.sock.Fd, buf, syscall.MSG_TRUNC); err != nil {
if e, ok := err.(syscall.Errno); ok && e.Temporary() {
continue
}
feed(GenlMessage{Error: err})
return
} else if bufN > len(buf) {
feed(GenlMessage{Error: fmt.Errorf("msg trunc")})
return
} else if msgs, err := syscall.ParseNetlinkMessage(buf[:bufN]); err != nil {
feed(GenlMessage{Error: err})
return
} else {
for _, msg := range msgs {
switch msg.Header.Type {
default:
feed(GenlMessage{
Header: msg.Header,
Family: self.familyIds[msg.Header.Type].Name,
Genl: (*GenlMsghdr)(unsafe.Pointer(&msg.Data[0])),
Payload: msg.Data[GENL_HDRLEN:],
})
case syscall.NLMSG_ERROR:
err := *(*syscall.NlMsgerr)(unsafe.Pointer(&msg.Data[0]))
feed(GenlMessage{
Header: msg.Header,
Error: MsgError{In: err},
})
case syscall.NLMSG_DONE:
feed(GenlMessage{
Header: msg.Header,
Genl: nil,
Payload: msg.Data,
})
}
}
}
}
}()
self.Add("nlctrl", "notify", self)
if res, err := self.Request("nlctrl", CTRL_VERSION, CTRL_CMD_GETFAMILY, syscall.NLM_F_DUMP, nil, nil); err != nil {
return nil, err
} else {
for _, r := range res {
self.GenlListen(r)
}
}
return self, nil
}
func NewRtHub() (*RtHub, error) {
self := &RtHub{
sock: NlSocketAlloc(),
lock: &sync.Mutex{},
unicast: make(map[uint32]chan RtMessage),
multicast: make(map[uint32][]RtListener),
}
if err := NlConnect(self.sock, syscall.NETLINK_ROUTE); err != nil {
NlSocketFree(self.sock)
return nil, err
}
go func() {
for {
var merr error
var messages []syscall.NetlinkMessage
var controls []syscall.SocketControlMessage
buf := make([]byte, syscall.Getpagesize())
oob := make([]byte, syscall.Getpagesize())
if bufN, oobN, _, _, err := syscall.Recvmsg(self.sock.Fd, buf, oob, syscall.MSG_TRUNC); err != nil {
if e, ok := err.(syscall.Errno); ok && e.Temporary() {
continue
}
merr = err
} else if bufN == 0 {
break
} else if bufN > len(buf) {
merr = err
} else if oobN > len(oob) {
merr = err
} else if msgs, err := syscall.ParseNetlinkMessage(buf[:bufN]); err != nil {
merr = err
} else if ctrls, err := syscall.ParseSocketControlMessage(oob[:oobN]); err != nil {
merr = err
} else {
messages = msgs
controls = ctrls
}
for _, message := range messages {
msg := RtMessage{
Message: message,
Controls: controls,
Error: merr,
}
seq := message.Header.Seq
mtype := message.Header.Type
if seq == 0 {
var listeners []RtListener
self.lock.Lock()
for _, s := range self.multicast {
listeners = append(listeners, s...)
}
self.lock.Unlock()
for _, listener := range listeners {
listener.RtListen(msg)
}
} else {
self.lock.Lock()
listener := self.unicast[seq]
self.lock.Unlock()
if listener != nil {
listener <- msg
if mtype == syscall.NLMSG_DONE || mtype == syscall.NLMSG_ERROR {
delete(self.unicast, seq)
close(listener)
}
}
}
}
}
}()
return self, nil
}
