/interface 6to4
add disabled=no local-address=aaa.bbb.ccc.ddd mtu=1480 name=6to4

/ipv6 address
add address=2002:AABB:CCDD:1::1/64 advertise=yes disabled=no eui-64=no interface=LAN
add address=2002:AABB:CCDD::1/16 advertise=no disabled=no eui-64=no interface=6to4

/ipv6 nd prefix default
set autonomous=yes

/ipv6 route
add disabled=no distance=1 dst-address=2000::/3 gateway=::192.88.99.1%6to4

/interface 6to4
add disabled=no local-address=192.0.2.1 name=6to4 remote-address=unspecified
/ipv6 address
add address=2002:c000:201::1/16 advertise=no comment=6to4public disabled=no \
    eui-64=no interface=6to4
add address=2002:c000:201:dead::1/64 advertise=yes comment=6to4subnet \
    disabled=no eui-64=no interface=LAN1
add address=2002:c000:201:beef::1/64 advertise=yes comment=6to4subnet \
    disabled=no eui-64=no interface=LAN2
/ipv6 nd prefix default
set autonomous=yes preferred-lifetime=2m valid-lifetime=5m
/ipv6 route
add disabled=no distance=1 dst-address=2000::/3 gateway=::192.88.99.1%6to4

# settings begin:

:local WANinterface "WAN"
:local 6to4interface "6to4"
:local PubAddrComment "6to4public"
:local SubnetAddrComment "6to4subnet"
:local LogPrefix "6to4update: "

#settings end.

:local WANaddress

:set WANaddress [/ip address get [/ip address find interface=$WANinterface] address]
:set WANaddress [:pick [:tostr $WANaddress] 0 [:find [:tostr $WANaddress] "/"]]

:if ([:len $WANaddress] = 0) do={
  :log error ($LogPrefix . "Could not get IP for interface " . $WANinterface)
  :error ("Could not get IP for interface " . $WANinterface)
}

:if ([/interface 6to4 get ($6to4interface) local-address] != $WANaddress) do={
  :log info ($LogPrefix . "Updating " . $6to4interface . " local-address with new IP " . $WANaddress . "...")
  /interface 6to4 set ($6to4interface) local-address=$WANaddress
   
  :set WANaddress ($WANaddress . ".")
  :local IP6prefix "2002:"
  :local num
  :local tn
  :local hi
  :local lo
  :local ar
  :local pos
  :local IP6part

  :for i from=0 to=1 do={
    :set IP6part ""  
    :for j from=0 to=1 do={
      :set pos [:find $WANaddress "."]
      :set num [:pick $WANaddress 0 $pos]
      :set WANaddress [:pick $WANaddress ($pos + 1) 99]
      :set tn [:tonum $num]
      :set hi ($tn / 16)
      :set lo ($tn - ($hi * 16))
      :set ar [:toarray ($hi . "," . $lo)]
      :foreach val in=$ar do={
        :if ($val < 10) do={
          :set IP6part ($IP6part . $val)
        } else={
          :if ($val = 10) do={ :set IP6part ($IP6part . "a") }
          :if ($val = 11) do={ :set IP6part ($IP6part . "b") }
          :if ($val = 12) do={ :set IP6part ($IP6part . "c") }
          :if ($val = 13) do={ :set IP6part ($IP6part . "d") }
          :if ($val = 14) do={ :set IP6part ($IP6part . "e") }
          :if ($val = 15) do={ :set IP6part ($IP6part . "f") }
        }
      }
    }
    :set IP6prefix ($IP6prefix . $IP6part . ":")
  }
  
  :foreach i in=[/ipv6 address find] do={
    :local addr [/ipv6 address get $i address]
    :local cmnt [/ipv6 address get $i comment]
    :local name [/ipv6 address get $i interface]
    :if ($cmnt = $PubAddrComment) do={
      :local newaddr ($IP6prefix . ":1/16")
      /ipv6 address set $i address=$newaddr
      :log info ($LogPrefix . "Changed address of interface " . $name . " from " . $addr . " to " . $newaddr)
    }
    :if ($cmnt = $SubnetAddrComment) do={
      :local tmp $addr
      :for j from=0 to=2 do={
        :set pos [:find $tmp ":"]
        :set tmp [:pick $tmp ($pos + 1) 99]
        :if ($j = 2) do={
          :set pos [:find $tmp ":"]
          :local newaddr ($IP6prefix . [:pick $tmp 0 $pos] . "::1/64")
          /ipv6 address set $i address=$newaddr
          :log info ($LogPrefix . "Changed address of interface " . $name . " from " . $addr . " to " . $newaddr)
        }
      }
    }
  }
  :log info ($LogPrefix . "Finished successfully.")
}
#EOF

/system scheduler
add comment="" disabled=no interval=5m name="Update 6to4" on-event=\
    update6to4 policy=read,write start-date=jan/01/1970 start-time=00:00:00