RFC: Use Inadyn to update DDNS

[fdcastel]

Problem: UDM-PRO internally uses Inadyn ddns client but the UI configuration offer very few DDNS providers:

As probably every other UDM-PRO customer out there, I waited patiently for Ubiquiti to provide me an update for this, which never happened. Of course, Ubiquiti surely have more important priorities like making a VR mobile app instead of adding real-world needed features (such load balancing or custom DNS records) into their 400.00 USD router.

So... Rants aside, I made this script to update my Cloudflare DDNS using Inadyn.

Just paste the script below, replacing MY_DOMAIN, MY_APIKEY and MY_HOST with appropriate values.

#
# Setup inadyn ddns
# 
SCRIPT_FILE=/data/on_boot.d/20-inadyn-custom.sh          # For Unifi OS 3.x
# SCRIPT_FILE=/mnt/data/on_boot.d/20-inadyn-custom.sh    # For Unifi OS 2.x
CONFIG_FILE=/run/ddns-ppp0-inadyn-custom.conf
PID_FILE=/run/inadyn-custom.pid

cat > $SCRIPT_FILE <<EOF
#!/bin/sh
#
# Start & stop the inadyn client (custom)
#

CONFIG_FILE=$CONFIG_FILE
PID_FILE=$PID_FILE

# Rebuild config file
cat > $CONFIG_FILE <<- 'INNER_EOF'
# Created by $SCRIPT_FILE
iface = ppp0

provider cloudflare {
    username = "MY_DOMAIN.com"
    password = "MY_APIKEY"
    hostname = "MY_HOST.MY_DOMAIN.com"
}
INNER_EOF
EOF

cat >> $SCRIPT_FILE <<'EOF'

# Main
case "$1" in
        stop)
                printf "Stopping inadyn-custom: "
                start-stop-daemon    -q -p $PID_FILE -x /usr/sbin/inadyn -K
                [ $? = 0 ] && echo "OK" || echo "FAIL"
                rm -f $PID_FILE
                ;;
        *)
                printf "Starting inadyn-custom: "
                start-stop-daemon -b -q -p $PID_FILE -x /usr/sbin/inadyn -S -m -- -n -s -C -f $CONFIG_FILE --no-pidfile
                [ $? = 0 ] && echo "OK" || echo "FAIL"
                ;;
esac

exit $?
EOF
chmod +x $SCRIPT_FILE
$SCRIPT_FILE

This will create a /mnt/data/on_boot.d/20-inadyn-custom.sh script which will start a second inadyn client. It uses a custom configuration file (recreated after each UDM reboot) and a custom PID file to not clash with the default inadyn managed by UDM firmware.

This setup is for Cloudflare but it can be used for any Inadyn supported providers.

Opinions, suggestions and criticisms are welcome.

[PrplHaz4]

Also of note, it doesn't seem the default inadyn client/web setup processes custom input parameters/tokens correctly, so this is (unfortunately) sorely needed IMO.

[fdcastel]

To anyone running Unifi OS 3.x / on-boot-script-v2.x: this script will work just fine changing the first line to

SCRIPT_FILE=/data/on_boot.d/20-inadyn-custom.sh

Since the persistent folder is now /data/on_boot.d instead of /mnt/data/on_boot.d.

[fdcastel]

Minor: using provider cloudflare in inadyn configuration causes the following entry log to appear in each run:

Guessing DDNS plugin 'default@cloudflare.com' from 'cloudflare'

To remove this use provider default@cloudflare.com which is the "correct" name for this provider.

Source.

[fdcastel]

systemd version:

#
# Setup inadyn ddns using systemd-run
# 
SCRIPT_FILE=/data/on_boot.d/20-inadyn-custom.sh          # For Unifi OS 3.x
CONFIG_FILE=/run/ddns-ppp0-inadyn-custom.conf

cat > $SCRIPT_FILE <<EOF
#!/bin/sh

CONFIG_FILE=$CONFIG_FILE

# Rebuild config file
cat > $CONFIG_FILE <<- 'INNER_EOF'
# Created by $SCRIPT_FILE
iface = ppp0

provider cloudflare {
    username = "MY_DOMAIN.com"
    password = "MY_APIKEY"
    hostname = "MY_HOST.MY_DOMAIN.com"
}
INNER_EOF

# Start transient service
systemd-run --unit=inadyn-custom-ppp0.service --description='Inadyn Dynamic DNS Client [ppp0]' /usr/sbin/inadyn -n -s -C -f $CONFIG_FILE --no-pidfile
EOF
chmod +x $SCRIPT_FILE

To check the service status:

systemctl status inadyn-custom-ppp0

To see the output logs:

journalctl -u inadyn-custom-ppp0