ipcalc.py

def ip2n(ip):
    """
    Convert an IP address in dotted quad to an integer
    """
    octets = ip.split('.')
    return sum([(int(octets[x]))<<(24-(8*x)) for x in range(0,4)])

def n2ip(n):
    """
    Convert an integer to a dotted quad ip address
    """
    return '.'.join( [str((n>>(24-(8*x)))&0xff) for x in range(0,4)] )

def cidrbits2mask(bits):
    """
    Given a number of bits (i.e. /bits), return a subnet mask
    """
    return n2ip(0xffffffff & ~int((2**(32-bits)-1)))

def cidr2range(cidr):
    """
    Convert CIDR notation to a range.
    """
    net,bits = cidr.split('/')
    bits = int(bits)
    net = ip2n(net)&ip2n(cidrbits2mask(bits))

    return (n2ip(net), n2ip(net+2**(32-bits)-1))

if __name__ == '__main__':
    print(n2ip(ip2n('192.168.1.1')))
    print(cidr2range('192.168.1.0/24'))