Conversion from IP string to integer, and backward

Question

i have a little problem with my script, where i need to convert ip in form 'xxx.xxx.xxx.xxx' to integer representation and go back from this form.

def iptoint(ip):
    return int(socket.inet_aton(ip).encode('hex'),16)

def inttoip(ip):
    return socket.inet_ntoa(hex(ip)[2:].decode('hex'))


In [65]: inttoip(iptoint('192.168.1.1'))
Out[65]: '192.168.1.1'

In [66]: inttoip(iptoint('4.1.75.131'))
---------------------------------------------------------------------------
error                                     Traceback (most recent call last)

/home/thc/<ipython console> in <module>()

/home/thc/<ipython console> in inttoip(ip)

error: packed IP wrong length for inet_ntoa`

Anybody knows how to fix that?

Answer 1

I used following:

ip2int = lambda ip: reduce(lambda a,b: long(a)*256 + long(b), ip.split('.'))

ip2int('192.168.1.1')

#output

3232235777L

# from int to ip
int2ip = lambda num: '.'.join( [ str((num >> 8*i) % 256)  for i in [3,2,1,0] ])

int2ip(3232235777L)

#output

'192.168.1.1'

Answer 2

#!/usr/bin/env python
import socket
import struct


def ip2int(addr):
    return struct.unpack("!I", socket.inet_aton(addr))[0]


def int2ip(addr):
    return socket.inet_ntoa(struct.pack("!I", addr))


print(int2ip(0xc0a80164)) # 192.168.1.100
print(ip2int('10.0.0.1')) # 167772161

Answer 3

One line

reduce(lambda out, x: (out << 8) + int(x), '127.0.0.1'.split('.'), 0)