scripts/bash/ydns-simple

#!/usr/bin/env bash
# This script is based on cf-ddns.sh found at
# <https://gist.github.com/larrybolt/6295160> and it's comments.
# Inspiration also took from
# <https://github.com/commx/ydns/blob/master/updater.sh> which is a lot
# more complex than this.

# yDNS details
USEREMAIL=""
PASSWORD=""
HOSTNAME=""

# Get IPv4 address
WAN_IP4=$(dig +short myip.opendns.com @resolver1.opendns.com)
if [ -f $HOME/.wan_ip4-ydns.txt ]; then
    OLD_WAN_IP4=$(cat $HOME/.wan_ip4-ydns.txt)
else
    echo "No file, need IP4"
    OLD_WAN_IP4=""
fi

# Get IPv6 address
WAN_IP6=$(dig +short myip.opendns.com AAAA @2620:0:ccc::2)
if [ -f $HOME/.wan_ip6-ydns.txt ]; then
    OLD_WAN_IP6=$(cat $HOME/.wan_ip6-ydns.txt)
else
    echo "No file, need IP6"
    OLD_WAN_IP6=""
fi

# Update IPv4
if [ "$WAN_IP4" = "$OLD_WAN_IP4" ]; then
    echo "IP4 Unchanged"
else
    echo $WAN_IP4 > $HOME/.wan_ip4-ydns.txt
    echo "Updating DNS to $WAN_IP4"
    curl -4 --basic -u "$USEREMAIL:$PASSWORD" --silent \
        https://ydns.eu/api/v1/update/?host=$HOSTNAME
fi

# Update IPv6
if [ "$WAN_IP6" = "$OLD_WAN_IP6" ]; then
    echo "IP6 Unchanged"
else
    echo $WAN_IP6 > $HOME/.wan_ip6-ydns.txt
    echo "Updating DNS to $WAN_IP6"
    curl -6 --basic -u "$USEREMAIL:$PASSWORD" --silent \
        https://ydns.eu/api/v1/update/?host=$HOSTNAME
fi