# HomingBeacon Main Dynamic DNS Update Script
# Written by Sam Norris, ChangeIP.com
# 20100728 Tested on RouterOS 4.9
# 20110511 Tested on RouterOS 5.2

# Set your specific ChangeIP.com preferences here.
:global ddnsuser "*****"
:global ddnspass "***************"
:global ddnshost "example.ddns.info"
# Change ddnsport to 8245 to bypass proxy.
:local ddnsport 8245

# Do not edit anything below this line.  You have been warned.
# Abusive updates to the system will cause firewall blocks.

# Please be considerate and
# do not let this script run more than once per 3-5 minutes.

:log info "DDNS: Starting."

# Initialize checkpoint
:global ddnscheckpoint
:if ([:typeof $ddnscheckpoint] = "time") do={
	:log info ("DDNS: Last check was " . ([/system clock get time] - $ddnscheckpoint))
} else={
	:log info "DDNS: Cannot determine checkpoint, set now."
	:global ddnscheckpoint ( [/system clock get time] - 1d )
}

# Get the current IP
:if ([/system clock get time] - $ddnscheckpoint > [:totime 180s] || [/system clock get time] - $ddnscheckpoint < [:totime 0s]) do={
   :log info "DDNS: Performing remote IP detection."
   /tool fetch address="ip.changeip.com" host="ip.changeip.com" src-path=("/?" . [/int eth get 0 mac-address ]) dst-path="ip.changeip.com.txt" mode=http port=$ddnsport
   :global ddnscheckpoint [/system clock get time]
} else={
   :log info "DDNS: Please be considerate and wait a few seconds longer."
   :break
}

# Parse the IP address received from fetch script.
	:global ddnslastip
	:local html [/file get "ip.changeip.com.txt" contents]
	:local ddnsip [:pick $html ([:find $html "<!--IPADDR="] + 11) [:find $html "-->"] ]

# Is it a valid IP and is it different than the last one?
	:if ([:typeof [:toip $ddnsip]] = "ip" AND $ddnsip != $ddnslastip ) do={
		:log warning"DDNS: Sending UPDATE with $ddnsip"
		:log info [/tool dns-update name=$ddnshost address=$ddnsip key-name=$ddnsuser key=$ddnspass ]
		:global ddnslastip $ddnsip
	} else={
		:log info "DDNS: No update required."
	}
}

# Based on a script found on the Internet.Will add attribution if I find it.
# Changed 20150719 by Graeme Ruthven (graeme@kula.co.nz)
# Modified to:
# - update using authentication in URL as original method appeared to stop working.
#   This was about the time of the RouterOS 6.30 release, but may be unrelated.
# - Get the previous IP from the contents of the dyndns.txt file, as the global variable
#   doesn't appear to persist.
#
# Reference: https://help.dyn.com/remote-access-api/perform-update/

:local username type here
:local password type here pass
:local hostname dxxxxx.dyndns.tv
:local emailAddress dxxxx@mail

:local url "dummy"
:local previousIP

:global dyndnsForce

:set dyndnsForce false

:log info ("UpdateDynDNS starts.")

# print some debug info
#:log info ("UpdateDynDNS: username = $username")
#:log info ("UpdateDynDNS: password = $password")
#:log info ("UpdateDynDNS: hostname = $hostname")
#:log info ("UpdateDynDNS: previousIP = $previousIP")

# I have some doubt over the persistence of the global previousIP.
# This value should be stored in /dyndns.txt after the last update attempt,
# preceded by the status and a space.
# For status values see: https://help.dyn.com/remote-access-api/return-codes/

:if ([:len [/file find name=dyndns.txt]] > 0) do={
   :local ipfile [/file get dyndns.txt contents]
   :local ipstart ([find $ipfile " " -1] + 1)
   :local ipend [:len $ipfile]
   :set previousIP [:pick $ipfile $ipstart $ipend]
} else={
   :set previousIP "0.0.0.0"
}

# get the current IP address from the internet (in case of double-nat)
/tool fetch mode=http address="checkip.dyn.com" src-path="/" dst-path="/dyndns.checkip.html"
:delay 1
:local result [/file get dyndns.checkip.html contents]

# parse the current IP result
:local resultLen [:len $result]
:local startLoc [:find $result ": " -1]
:set startLoc ($startLoc + 2)
:local endLoc [:find $result "</body>" -1]
:local currentIP [:pick $result $startLoc $endLoc]

# Remove the # on next line to force an update every single time - useful for debugging,
# but you could end up getting blacklisted by DynDNS!

#:set dyndnsForce true

# Determine if dyndns update is needed
# more dyndns updater request details http://www.dyndns.com/developers/specs/syntax.html

:if (($currentIP != $previousIP) || ($dyndnsForce = true)) do={
   :log info ("Changing IP from $previousIP to $currentIP.")
   :set dyndnsForce false
   :set url "http://$username:$password@members.dyndns.org/nic/update?hostname=$hostname&myip=$currentIP&wildcard=no"
   /tool fetch url=$url mode=http dst-path="/dyndns.txt"
 
# Original code:
#   /tool fetch user=$username password=$password mode=http address="members.dyndns.org" \
#      src-path="nic/update?system=dyndns&hostname=$hostname&myip=$currentIP&wildcard=no" \
#      dst-path="/dyndns.txt"

   :delay 1

 #  :set previousIP $currentIP

   :local result [/file get dyndns.txt contents]
   :log info ("UpdateDynDNS: Dyndns update needed")
   :log info ("UpdateDynDNS: Dyndns Update Result: ".$result)

# email result:
   :local output "DynDNS Update Result: $result"
   /tool e-mail send to="$emailAddress" subject="DynDNS update $currentTime" body="$output"
} else={
   :log info ("UpdateDynDNS: No dyndns update needed")
}