Script to pull country-specific IP ranges from ipdeny.com and create/update country-specific ipsets from them

update-country-ipsets.sh

#!/bin/bash
#
# Powered by <a href="http://www.ipdeny.com">IPDENY.COM</a> IP database.
#
# Pull the agregated zone lists from denyip.com, and create country-specific ipsets from them
#
# This approach doesn't require an additional 'geoip' kernel module or the Maxmind database. 
#
# When updating, the new ipset replaces the existing one with a 'swap', so there isn't any
# time period when the set is empty.
#
# Paul Chambers, August 5, 2023
#

countries='gb ca'

for country in ${countries}
do
    url="https://www.ipdeny.com/ipblocks/data/aggregated/${country}-aggregated.zone"

    ipset create "country-${country}-import" hash:net && ipset -! create "country-${country}" hash:net

    while IF= read -r cidr
    do
        ipset add "country-${country}-import" "${cidr}"
    done < <(curl "${url}")

    ipset swap "country-${country}-import" "country-${country}" && ipset destroy "country-${country}-import"
done