req := &nl.NetlinkRequest{
		// netlink message header
		// (definition: https://github.com/torvalds/linux/blob/v6.7/include/uapi/linux/netlink.h#L44-L58)
		NlMsghdr: unix.NlMsghdr{
			Len:   uint32(unix.SizeofNlMsghdr),
			Type:  uint16(cmd | (unix.NFNL_SUBSYS_ACCT << 8)),
			Flags: flags,
		},
		Sockets: map[int]*nl.SocketHandle{
			unix.NETLINK_NETFILTER: {Socket: n.socket},
		},

//sys   sendto(s int, buf []byte, flags int, to unsafe.Pointer, addrlen _Socklen) (err error)
//sys	recvmsg(s int, msg *Msghdr, flags int) (n int, err error)

func recvmsgRaw(fd int, p, oob []byte, flags int, rsa *RawSockaddrAny) (n, oobn int, recvflags int, err error) {
	var msg Msghdr
	msg.Name = (*byte)(unsafe.Pointer(rsa))
	msg.Namelen = uint32(SizeofSockaddrAny)
	var iov Iovec
	if len(p) > 0 {
		iov.Base = &p[0]

//sys	Shutdown(s int, how int) (err error)

// In order to use msghdr structure with Control, Controllen in golang.org/x/net,
// nrecvmsg and nsendmsg must be used.
//sys	recvmsg(s int, msg *Msghdr, flags int) (n int, err error) = nrecvmsg
//sys	sendmsg(s int, msg *Msghdr, flags int) (n int, err error) = nsendmsg

func (sa *SockaddrInet4) sockaddr() (unsafe.Pointer, _Socklen, error) {

//sys	sendto(s int, buf []byte, flags int, to unsafe.Pointer, addrlen _Socklen) (err error)

// In order to use msghdr structure with Control, Controllen, nrecvmsg and nsendmsg must be used.
//sys	recvmsg(s int, msg *Msghdr, flags int) (n int, err error) = nrecvmsg
//sys	sendmsg(s int, msg *Msghdr, flags int) (n int, err error) = nsendmsg

//sys	munmap(addr uintptr, length uintptr) (err error)

	}

	sock, err := sysSocket(syscall.AF_INET, syscall.SOCK_DGRAM, 0)
	if err != nil {
		return nil, err
	}
	defer poll.CloseFunc(sock)

	var ift []Interface
	for len(tab) > 0 {
		ifm := (*syscall.IfMsgHdr)(unsafe.Pointer(&tab[0]))
		if ifm.Msglen == 0 {
			break
		}
		if ifm.Type == syscall.RTM_IFINFO {
			if ifindex == 0 || ifindex == int(ifm.Index) {

	p := (*InterfaceMessage)(unsafe.Pointer(any))
	// FreeBSD 10 and beyond have a restructured mbuf
	// packet header view.
	// See https://svnweb.freebsd.org/base?view=revision&revision=254804.
	m := (*ifMsghdr)(unsafe.Pointer(any))
	p.Header.Data.Hwassist = uint32(m.Data.Hwassist)
	p.Header.Data.Epoch = m.Data.Epoch
	p.Header.Data.Lastchange = m.Data.Lastchange

//sys	sendto(s int, buf []byte, flags int, to unsafe.Pointer, addrlen _Socklen) (err error)
//sys	recvmsg(s int, msg *Msghdr, flags int) (n int, err error)

func recvmsgRaw(fd int, iov []Iovec, oob []byte, flags int, rsa *RawSockaddrAny) (n, oobn int, recvflags int, err error) {
	var msg Msghdr
	msg.Name = (*byte)(unsafe.Pointer(rsa))
	msg.Namelen = uint32(SizeofSockaddrAny)
	var dummy byte
	if len(oob) > 0 {

		return
	}
	oobn = int(msg.Accrightslen)
	return
}

//sys	sendmsg(s int, msg *Msghdr, flags int) (n int, err error) = libsocket.__xnet_sendmsg

func sendmsgN(fd int, p, oob []byte, ptr unsafe.Pointer, salen _Socklen, flags int) (n int, err error) {
	var msg Msghdr
	msg.Name = (*byte)(unsafe.Pointer(ptr))
	msg.Namelen = uint32(salen)
	var iov Iovec
	if len(p) > 0 {

	SYS_PTRACE         = 26  // { int sys_ptrace(int req, pid_t pid, caddr_t addr, int data); }
	SYS_RECVMSG        = 27  // { ssize_t sys_recvmsg(int s, struct msghdr *msg, int flags); }
	SYS_SENDMSG        = 28  // { ssize_t sys_sendmsg(int s, const struct msghdr *msg, int flags); }
	SYS_RECVFROM       = 29  // { ssize_t sys_recvfrom(int s, void *buf, size_t len, int flags, struct sockaddr *from, socklen_t *fromlenaddr); }

	SYS_PTRACE         = 26  // { int sys_ptrace(int req, pid_t pid, caddr_t addr, int data); }
	SYS_RECVMSG        = 27  // { ssize_t sys_recvmsg(int s, struct msghdr *msg, int flags); }
	SYS_SENDMSG        = 28  // { ssize_t sys_sendmsg(int s, const struct msghdr *msg, int flags); }
	SYS_RECVFROM       = 29  // { ssize_t sys_recvfrom(int s, void *buf, size_t len, int flags, struct sockaddr *from, socklen_t *fromlenaddr); }