Go - CIDR to IPs

cidr.go

package main

func IPsFromCIDR(cidr string) ([]net.IP, error) {
	_, ipNet, err := net.ParseCIDR(cidr)
	if err != nil {
		return nil, err
	}

	ones, bits := ipNet.Mask.Size()
	addrCount := 1 << (bits - ones)

	ip := ipNet.IP
	result := make([]net.IP, 0, addrCount)
	for x := 0; x < addrCount; x++ {
		result = append(result, cloneIP(ip))
		incrementIP(ip)
	}

	return result, nil
}

func cloneIP(src net.IP) net.IP {
	dest := make(net.IP, len(src))
	copy(dest, src)
	return dest
}

func incrementIP(ip net.IP) {
	for i := len(ip) - 1; i >= 0; i-- {
		ip[i]++
		//only add to the next byte if we overflowed
		if ip[i] != 0 {
			break
		}
	}
}