@startuml

Title Append requested options algorithm (Kea 1.8.0)

:get configured option list;

:get parameter request list (PRL) from query;

while (for each item from configured option list)
  :get configured options in dhcp4 space;
  while (for each persistent option)
    :push back option code to PRL;
  endwhile
endwhile

while (for each code in PRL)
  if (option is not set in response) then (yes)
    while (for each item from configured option list)
      :get configured options in dhcp4 space;
      if (found) then (first)
        :add option to response;
      else (not found or already found)
      endif
    endwhile
  else (no)
  endif
endwhile
->done;
stop

@enduml