rough script, still in development

iprange_to_cidrs.go

package main

import (
	"fmt"
	"math"
	"strconv"
	"strings"
)

func IPToInt(ip string) uint {
	octets := strings.Split(ip, ".")
	ipint := float64(0)
	for i := 0; i < 4; i++ {
		octet, _ := strconv.ParseFloat(octets[i], 64)
		ipint += octet * math.Pow(float64(256), float64(3-i))
	}
	return uint(ipint)
}

func IntToIP(ipint int) string {
	return fmt.Sprintf("%d.%d.%d.%d", ipint>>24, ipint>>16&0xFF, ipint>>8&0xFF, ipint&0xFF)
}

func IPRangeToCIDR(startip, endip uint) {
	bits := uint(1)
	mask := uint(1)
	newip := uint(0)
	for bits < 32 {
		newip = startip | mask
		if newip > endip || ((startip>>bits)<<bits) != startip {
			bits = bits - 1
			mask = mask >> 1
			break
		}
		bits = bits + 1
		mask = (mask << 1) + 1
	}
	newip = startip | mask
	bits = 32 - bits
	fmt.Printf("%s/%d\n", IntToIP(int(startip)), bits)
	if newip < endip {
		IPRangeToCIDR(newip+1, endip)
	}
}

func main() {
	fmt.Println("iprange to cidr")
	fmt.Println(IPToInt("66.207.219.190"))
	fmt.Println(IntToIP(1120918462))
	IPRangeToCIDR(IPToInt("221.192.0.0"), IPToInt("221.199.207.255"))
}