//go:nosplit
//go:cgo_unsafe_args
func closefd(fd int32) int32 {
	return libcCall(unsafe.Pointer(abi.FuncPCABI0(close_trampoline)), unsafe.Pointer(&fd))
}
func close_trampoline()

//go:nosplit
//go:cgo_unsafe_args
func read(fd int32, p unsafe.Pointer, n int32) int32 {
	ret := libcCall(unsafe.Pointer(abi.FuncPCABI0(read_trampoline)), unsafe.Pointer(&fd))
	KeepAlive(p)
	return ret
}
func read_trampoline()

	var devPath [len(hpetDevPath)]byte
	copy(devPath[:], hpetDevPath)
	devPath[9] = digits[idx]

	fd := open(&devPath[0], 0 /* O_RDONLY */ |_O_CLOEXEC, 0)
	if fd < 0 {
		atomic.Casuintptr(&hpetDevMap[idx], 0, ^uintptr(0))
		return
	}

	addr, mmapErr := mmap(nil, physPageSize, _PROT_READ, _MAP_SHARED, fd, 0)
	closefd(fd)
	newP := uintptr(addr)
	if mmapErr != 0 {
		newP = ^uintptr(0)
	}

	}
	return &NetnsWrapper{innerNetns: n, inode: i}, nil
}

func NetnsSet(n NetnsFd) error {
	if err := unix.Setns(int(n.Fd()), unix.CLONE_NEWNET); err != nil {
		return fmt.Errorf("Error switching to ns fd %v: %v", n.Fd(), err)
	}
	return nil
}

// inspired by netns.Do() but with an existing fd.
func NetnsDo(fdable NetnsFd, toRun func() error) error {
	containedCall := func() error {
		threadNS, err := netns.GetCurrentNS()

	}
	if hook.called && hook.srcfd != int(src.Fd()) {
		t.Fatalf("wrong source file descriptor: got %d, want %d", hook.srcfd, src.Fd())
	}
	sc, ok := dst.(syscall.Conn)
	if !ok {
		t.Fatalf("destination is not a syscall.Conn")
	}
	rc, err := sc.SyscallConn()
	if err != nil {
		t.Fatalf("destination SyscallConn error: %v", err)
	}
	if err = rc.Control(func(fd uintptr) {
		if hook.called && hook.dstfd != int(fd) {

func GetOriginalDestination(conn net.Conn) (daddr net.IP, dport uint16, err error) {
	// obtain os fd from Conn
	tcp, ok := conn.(*net.TCPConn)
	if !ok {
		err = errors.New("socket is not tcp")
		return
	}
	file, err := tcp.File()
	if err != nil {
		return
	}
	defer file.Close()
	fd := file.Fd()

	// Detect underlying ip is v4 or v6
	ip := conn.RemoteAddr().(*net.TCPAddr).IP
	isIpv4 := false

func sendFile(fd *netFD, r io.Reader) (written int64, err error, handled bool) {
	var n int64 = 0 // by default, copy until EOF.

	lr, ok := r.(*io.LimitedReader)
	if ok {
		n, r = lr.N, lr.R
		if n <= 0 {
			return 0, nil, true
		}
	}

	f, ok := r.(*os.File)
	if !ok {
		return 0, nil, false
	}

	written, err = poll.SendFile(&fd.pfd, syscall.Handle(f.Fd()), n)
	if err != nil {

func read(fd int32, p unsafe.Pointer, n int32) int32

func closefd(fd int32) int32

func exit(code int32)
func usleep(usec uint32)

//go:nosplit
func usleep_no_g(usec uint32) {
	usleep(usec)
}

// write1 calls the write system call.
// It returns a non-negative number of bytes written or a negative errno value.
//
//go:noescape
func write1(fd uintptr, p unsafe.Pointer, n int32) int32

		widx = to
	}
	pd.user = uint32(ridx)<<16 | uint32(widx)
	if to != disarmed {
		subs[to], subs[from] = subs[from], subs[to]
	}
}

func netpollclose(fd uintptr) int32 {
	lock(&mtx)
	for i := 0; i < len(pds); i++ {
		if pds[i].fd == fd {
			netpolldisarm(pds[i], 'r'+'w')
			pds[i] = pds[len(pds)-1]
			pds = pds[:len(pds)-1]
			break
		}
	}
	unlock(&mtx)
	return 0
}

	}
	return ts.tv_sec, int32(ts.tv_nsec)
}

//go:nosplit
func fcntl(fd, cmd, arg int32) (int32, int32) {
	r, errno := syscall3(&libc_fcntl, uintptr(fd), uintptr(cmd), uintptr(arg))
	return int32(r), int32(errno)
}

//go:nosplit
func setNonblock(fd int32) {
	flags, _ := fcntl(fd, _F_GETFL, 0)
	if flags != -1 {
		fcntl(fd, _F_SETFL, flags|_O_NONBLOCK)
	}
}

	}
	closeonexec(kq)
	addWakeupEvent(kq)
}

func netpollopen(fd uintptr, pd *pollDesc) int32 {
	// Arm both EVFILT_READ and EVFILT_WRITE in edge-triggered mode (EV_CLEAR)
	// for the whole fd lifetime. The notifications are automatically unregistered
	// when fd is closed.
	var ev [2]keventt
	*(*uintptr)(unsafe.Pointer(&ev[0].ident)) = fd
	ev[0].filter = _EVFILT_READ
	ev[0].flags = _EV_ADD | _EV_CLEAR
	ev[0].fflags = 0