@startuml

/'
This UML uses the new syntax of activity diagrams from plantuml.
Unfortunately, it also results in a more wide spread of the resulting
visual diagram, so wide that it becomes unreadable when automatically
scaled down in the ARM. This is the reason for the aggressive word
wrapping below - to force the diagram to be longer and less wide, and
as a result - more readable.
'/

start

title How Kea Recognizes the Same Client In Different DHCP Messages (Kea 2.4.0)

if (libdhcp_flex_id.so is used) then (yes)
  if (replace-client-id is true (the default)) then (yes)
    #palegreen:Client is recognized
    by the result of the
    identifier
    expression in
    libdhcp_flex_id.so.;
    stop
  else (no)
    if (client has a reservation) then (yes)
      if () then (for the purpose
of acquiring a reservation)
        #palegreen:Client is recognized
        by the result of the
        identifier
        expression in
        libdhcp_flex_id.so.;
        stop
      else (for the purpose
of leasing outside a
reservation or acquiring
any other value outside
of reservations)
        :Go through the
        diagram from the
        beginning as if
        libdhcp_flex_id.so
        is unused.;
        stop
      endif
    else (no)
      :Go through the
      diagram from the
      beginning as if
      libdhcp_flex_id.so
      is unused.;
      stop
    endif
  endif
else (no)
  if (DHCPv4
or
DHCPv6?) then (DHCPv4)
    if (MAC
address is
present) then (yes)
      if (match-client-id
is true
(the default)) then (yes)
        if (client ID option (code 61) is present) then (yes)
          #palegreen:Client is recognized
          by the client ID
          option (code 61).;
          stop
        else (no)
          #palegreen:Client is recognized
          by the MAC address.;
          stop
        endif
      else (no)
        #palegreen:Client is recognized
        by the MAC address.;
        stop
      endif
    else (no)
      #pink:DHCP message is not
      well formed.;
      stop
    endif
  else (DHCPv6)
    if (client ID
option (code 1) is
present) then (yes)
      if (interested in
identifying as a
single client -
the device or
the lease) then (device)
        #palegreen:Client is recognized
        by the client ID
        option (code 1) aka
        DUID.;
        stop
      else (lease)
        #palegreen:Client is recognized
        by the tuple
        <DUID, IA-type, IAID>.;
        stop
      endif
    else (no)
      #pink:DHCP message is not
      well formed.;
      stop
    endif
  endif
endif

@enduml