Skip to content

Instantly share code, notes, and snippets.

@ChrisTM
Last active April 20, 2022 09:35
Show Gist options
  • Save ChrisTM/7cf6d5409e8cec1497ff to your computer and use it in GitHub Desktop.
Save ChrisTM/7cf6d5409e8cec1497ff to your computer and use it in GitHub Desktop.
Convert IPv4 addresses to and from integers
"""
Convert between various representations of an IPv4 address.
`ip` refers to a dotted string, like: `'127.0.0.1'`.
`octets` are indexables, like `(127, 0, 0, 1)`.
`int` is the integer representation, like `2130706433`.
Written for Python 2.7.
"""
import itertools
def ip_to_octets(ip):
return map(int, ip.split('.'))
def octets_to_ip(octets):
return '.'.join(map(str, octets))
def octets_to_int(octets):
return (
(octets[0] << 24) ^
(octets[1] << 16) ^
(octets[2] << 8) ^
(octets[3] << 0)
)
def int_to_octets(int_):
return (
(int_ >> 24) & 0xff,
(int_ >> 16) & 0xff,
(int_ >> 8) & 0xff,
(int_ >> 0) & 0xff,
)
def int_to_ip(int_):
return octets_to_ip(int_to_octets(int_))
def ip_to_int(ip):
"""
Return the integer representation of a dotted IPV4 address.
Useful for comparisons and as a sort key. For example, the expression:
sorted(['0.0.0.100', '0.0.0.20', '0.0.0.3'], key=ip_to_int)
puts '0.0.0.20' in the middle instead of at the end, which a naive sort
would do.
"""
return octets_to_int(ip_to_octets(ip))
def ip_range(start_ip, end_ip):
"""
Return an iterator of the IP addresses between `start_ip` and `end_ip`,
inclusive.
"""
start_int = ip_to_int(start_ip)
end_int = ip_to_int(end_ip)
# CPython's `xrange` is implemented with unsigned longs and overflows when
# used with IP addresses greater than 127.255.255.255.
int_range = itertools.islice(
itertools.count(start_int),
end_int - start_int + 1
)
ip_range = itertools.imap(int_to_ip, int_range)
return ip_range
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment