buildhosts/p2p-to-hosts

#!/usr/bin/env bash

if [[ -z "$1" ]] || [[ -z "$2" ]]; then
    echo "Error: Run this scrip with a blocklist URL in p2p format and an output file as arguments"
    exit 1
fi

P2PLIST=$(sed 's|^.*:||' < <(wget -q -O - "$1" | gunzip) | grep -E "^[0-9]*.[0-9]*.[0-9]*.[0-9]*-[0-9]*.[0-9]*.[0-9]*.[0-9]*$")
[[ ! $(grep -E "^[0-9]*.[0-9]*.[0-9]*.[0-9]*-[0-9]*.[0-9]*.[0-9]*.[0-9]*$" <<< "$P2PLIST") ]] && echo "Error: The URL ${1} does not appear to contain a P2P-formatted blocklist" && exit 1

for address_range in ${P2PLIST[@]}; do
    IP1=$(cut -d '-' -f 1 <<< "$address_range")
    IP1_1=$(cut -d '.' -f 1 <<< "$IP1")
    IP1_2=$(cut -d '.' -f 2 <<< "$IP1")
    IP1_3=$(cut -d '.' -f 3 <<< "$IP1")
    IP1_4=$(cut -d '.' -f 4 <<< "$IP1")

    IP2=$(cut -d '-' -f 2 <<< "$address_range")

    echo "127.0.0.1 ${IP1_1}.${IP1_2}.${IP1_3}.${IP1_4}" >> "$2"
    while [ ! "${IP1_1}.${IP1_2}.${IP1_3}.${IP1_4}" = "$IP2" ]; do
        if [ "$IP1_4" -lt 255 ]; then
            IP1_4=$(expr $IP1_4 + 1)
        else
            IP1_4=0
            if [ "$IP1_3" -lt 255 ]; then
                IP1_3=$(expr $IP1_3 + 1)
            else
                IP1_3=0
                if [ "$IP1_2" -lt 255 ]; then
                    IP1_2=$(expr $IP1_2 + 1)
                else
                    IP1_2=0
                    if [ "$IP1_1" -lt 255 ]; then
                        IP1_1=$(expr $IP1_1 + 1)
                    else
                        break
                    fi
                fi
            fi
        fi
        echo "127.0.0.1 ${IP1_1}.${IP1_2}.${IP1_3}.${IP1_4}" >> "$2"
    done
done