ip.py

# simple IP address calcs
 
import sys, socket, struct
 
def dottedQuadToNum(ip):
    "convert decimal dotted quad string to long integer"
    return struct.unpack('L',socket.inet_aton(ip))[0]
 
def numToDottedQuad(n):
    "convert long int to dotted quad string"
    return socket.inet_ntoa(struct.pack('L',n))
 
def makeMask(n):
    "return a mask of n bits as a long integer"
    return (2L<<n-1)-1
 
def ipToNetAndHost(ip, maskbits):
    "returns tuple (network, host) dotted-quad addresses given IP and mask size"
 
    n = dottedQuadToNum(ip)
    m = makeMask(maskbits)
 
    host = n & m
    net = n - host
 
    return numToDottedQuad(net), numToDottedQuad(host)
 
if __name__=='__main__':
    for fn in sys.argv[1:]:
        try: print numToDottedQuad(long(fn))
        except: print dottedQuadToNum(fn)