var l int
	for _, a := range as {
		switch a := a.(type) {
		case *LinkAddr:
			_, ll := a.lenAndSpace()
			l += ll
		case *Inet4Addr:
			_, ll := a.lenAndSpace()
			l += ll
		case *Inet6Addr:
			_, ll := a.lenAndSpace()
			l += ll
		case *DefaultAddr:
			_, ll := a.lenAndSpace()
			l += ll
		}
	}
	return l
}