IP prefix within range

ip_prefix_within_range.py

#!/usr/local/bin/python3

def ipPrefixRange(addr, start, end):
    """
    @param  addr     valid String of ip address e.g. 192.168.0.0/16
    @param  start    int range to start iteration from
    @param  end      int range to end the iteration with
    @return [String] list of string of possible prefixes between start and end
    """
    assert start <= end

    addrs  = addr.split('/')
    ipAddr = ipStrToInt(addrs[0])
    prefix = int(addrs[1])
    assert prefix <= start

    result = []

    idx = start
    while idx <= end:
        for i in range(2 ** (idx - prefix)):
            result.append(ipIntToStr(ipAddr + (i << (32 - idx))) + "/" + str(idx))
        idx += 1

    return result

def ipIntToStr(ipInt):
    res = str(ipInt % 256)
    ipInt //= 256
    res = str(ipInt % 256) + '.' + res
    ipInt //= 256
    res = str(ipInt % 256) + '.' + res
    ipInt //= 256
    res = str(ipInt % 256) + '.' + res
    return res

def ipStrToInt(ipStr):
    ips = ipStr.split('.')
    assert len(ips) == 4
    return (int(ips[0]) << 24) + (int(ips[1]) << 16) + (int(ips[2]) << 8) + int(ips[3])


if __name__ == "__main__":
    # print(ipIntToStr(ipStrToInt('0.0.0.1')) == '0.0.0.1')
    # print(ipIntToStr(ipStrToInt('192.168.64.129')) == '192.168.64.129')
    # print(ipPrefixRange('192.168.0.0/16', 18, 18))
    # print(ipPrefixRange('192.168.0.0/16', 16, 17))
    # print(ipPrefixRange('192.168.0.0/16', 16, 18))
    print(ipPrefixRange('192.168.0.0/16', 18, 20))