const _RTAX_NETMASK = 2
const _RTAX_IFA = 5
const _RTAX_MAX = 8

func getIfList() ([]byte, error) {
	needed, err := syscall.Getkerninfo(_KINFO_RT_IFLIST, 0, 0, 0)
	if err != nil {
		return nil, err
	}
	tab := make([]byte, needed)
	_, err = syscall.Getkerninfo(_KINFO_RT_IFLIST, uintptr(unsafe.Pointer(&tab[0])), uintptr(unsafe.Pointer(&needed)), 0)
	if err != nil {
		return nil, err
	}
	return tab[:needed], nil