Cloudflare DDNS Provider for Synology

cloudflare.sh

#!/bin/sh

_exit() {
    echo $1
    exit
}

if [[ "$#" -ne 4 ]]; then
    _exit "badparam"
fi

ZONE_ID=$1
API_TOKEN=$2
HOSTNAME=$3
IPv6=$(ip -6 --brief addr show dev eth1 scope global | awk '{ print $3 }' | sed -e 's/\/.*//')

list_dns_records() {
    RESULT=$(
        curl -s -X GET "https://api.cloudflare.com/client/v4/zones/${ZONE_ID}/dns_records?type=AAAA&name=${HOSTNAME}&match=all" \
            -H "Authorization: Bearer ${API_TOKEN}" \
            -H "Content-Type: application/json"
    )
    if [[ $? -ne 0 ]]; then
        _exit "badconn"
    fi
    RESULT_OK=$(echo $RESULT | jq '.success')
}

patch_dns_record() {
    RESULT=$(
        curl -s -X PATCH "https://api.cloudflare.com/client/v4/zones/${ZONE_ID}/dns_records/${1}" \
            -H "Authorization: Bearer ${API_TOKEN}" \
            -H "Content-Type: application/json" \
            --data "${2}"
    )
    if [[ $? -ne 0 ]]; then
        _exit "badconn"
    fi
    RESULT_OK=$(echo $RESULT | jq -r '.success')
}

list_dns_records
if [[ ! $RESULT_OK ]]; then
    if [[ $(echo $RESULT | jq -r '.errors[0].code') -eq 10000 ]]; then
        _exit "badauth"
    fi
    _exit "badagent"
fi

RECORDS=$(echo $RESULT | jq '.result')
if [[ $(echo $RECORDS | jq -r 'length') -le 0 ]]; then
    _exit "nohost"
fi

RECORD=$(echo $RECORDS | jq '.[0]')
PATCHED_RECORD=$(echo $RECORD | jq -r "{ content: \"$IPv6\" } | tostring")

patch_dns_record $(echo $RECORD | jq -r '.id') $PATCHED_RECORD
if [[ ! $RESULT_OK ]]; then
    if [[ $(echo $RESULT | jq -r '.errors[0].code') -eq 10000 ]]; then
        _exit "badauth"
    fi
    _exit "badagent"
fi

_exit "good"