Dynamic DNS script using Cloudflare API v4

cf-ddns.sh

#!/bin/bash

# can be A or AAAA
do_record=AAAA
# the interface to get ipv6 address
iface=eth0
# the static suffix we should add to
v6_suf=53

mail="[email protected]"
authkey="012345689abcdef0123456789abcdef"
record=aaa.com

cachef=/tmp/ddns-$record

cfupdate () {
	_type=$1
	_addr=$2
	echo "Update $_type record for $record to $_addr"

	ret=$(curl -s -X PUT "https://api.cloudflare.com/client/v4/zones/$zoneid/dns_records/$recordid" \
		-H "X-Auth-Email: $mail" \
		-H "X-Auth-Key: $authkey" \
		-H "Content-Type: application/json" \
		--data '{"type":"'$_type'","name":"'$record'","content":"'$_addr'"}')
	
	if [[ -z $(echo $ret|grep -oP "success\":[^\"]+"|grep true) ]]; then
		echo $ret
	else
		echo "OK."
	fi
}

if [[ ! -e $cachef ]]; then
	touch $cachef
fi

if [[  $(cat $cachef|grep "id,"|wc -l) -ne 2 ]]; then
	domain=$(echo $record |grep -oP "[^.]+\.[^.]+$")
	ret=$(curl -s -X GET "https://api.cloudflare.com/client/v4/zones?name=$domain" \
		-H "X-Auth-Email: $mail" \
		-H "X-Auth-Key: $authkey" \
		-H "Content-Type: application/json")
	zoneid=$(echo $ret|grep -oP "\"id\":\"[a-f\d]{32}"|grep -oP "[a-f\d]{32}"|head -n1)
	ret=$(curl -s -X GET "https://api.cloudflare.com/client/v4/zones/$zoneid/dns_records?name=$record&type=$do_record" \
		-H "X-Auth-Email: $mail" \
		-H "X-Auth-Key: $authkey" \
		-H "Content-Type: application/json")
	recordid=$(echo $ret|grep -oP "\"id\":\"[a-f\d]{32}"|grep -oP "[a-f\d]{32}"|head -n1)
	echo "recordid,$do_record,$recordid" >> $cachef
	echo "zoneid,$zoneid" >> $cachef
else
	recordid=$(cat $cachef|grep "recordid,$do_record"|grep -oP "[a-f\d]{32}")
	zoneid=$(cat $cachef|grep zoneid|grep -oP "[a-f\d]{32}")
fi

if [[ -z $recordid || -z $zoneid ]]; then
    echo "Unable to get recordid or zoneid"
    rm -f $cachef
    exit 0
fi

if [[ $do_record = "A" ]]; then 
    addr_v4=$(curl ipip.tk/ip -4s)

    if [[ -z $(cat $cachef|grep $addr_v4) ]]; then
            sed -i "/v4,/d" $cachef
            echo "v4,$addr_v4" >> $cachef
            cfupdate "A" $addr_v4
    fi
else
    # check if we have ipv6 address

    if [[ -z $(ifconfig $iface|grep inet6|grep -P "2[\da-f:]{4,}") ]]; then exit; fi

    addr_v6_prefix=$(curl ipip.tk/ip -6s|grep -oP "[\da-f]+:[\da-f]+:[\da-f]+:[\da-f]+"|cut -f1|head -n1 )

    # check if we really can use ipv6
    if [[ -z $addr_v6_prefix ]]; then exit; fi

    addr_v6="$addr_v6_prefix::$v6_suf"

    if [[ -z $(ifconfig $iface|grep $addr_v6) ]]; then
        echo "Adding $addr_v6 to $iface"
        ip -6 addr add $addr_v6/64 dev $iface
    fi


    if [[ -z $(cat $cachef|grep $addr_v6) ]]; then
        sed -i "/v6,/d" $cachef
        echo "v6,$addr_v6" >> $cachef
        cfupdate "AAAA" $addr_v6
    fi
fi