11.4 通过CIDR地址生成对应的IP地址集

问题¶

You have a CIDR network address such as “123.45.67.89/27,” and you want to generate a range of all the IP addresses that it represents (e.g., “123.45.67.64,” “123.45.67.65,” …, “123.45.67.95”).

解决方案¶

The ipaddress module can be easily used to perform such calculations. For example:

>>> import ipaddress
>>> net = ipaddress.ip_network('123.45.67.64/27')
>>> net
IPv4Network('123.45.67.64/27')
>>> for a in net:
...     print(a)
...
123.45.67.64
123.45.67.65
123.45.67.66
123.45.67.67
123.45.67.68
...
123.45.67.95
>>>

>>> net6 = ipaddress.ip_network('12:3456:78:90ab:cd:ef01:23:30/125')
>>> net6
IPv6Network('12:3456:78:90ab:cd:ef01:23:30/125')
>>> for a in net6:
...     print(a)
...
12:3456:78:90ab:cd:ef01:23:30
12:3456:78:90ab:cd:ef01:23:31
12:3456:78:90ab:cd:ef01:23:32
12:3456:78:90ab:cd:ef01:23:33
12:3456:78:90ab:cd:ef01:23:34
12:3456:78:90ab:cd:ef01:23:35
12:3456:78:90ab:cd:ef01:23:36
12:3456:78:90ab:cd:ef01:23:37
>>>

Network objects also allow indexing like arrays. For example:

>>> net.num_addresses
32
>>> net[0]

IPv4Address(‘123.45.67.64’) >>> net[1] IPv4Address(‘123.45.67.65’) >>> net[-1] IPv4Address(‘123.45.67.95’) >>> net[-2] IPv4Address(‘123.45.67.94’) >>>

In addition, you can perform operations such as a check for network membership:

>>> a = ipaddress.ip_address('123.45.67.69')
>>> a in net
True
>>> b = ipaddress.ip_address('123.45.67.123')
>>> b in net
False
>>>

An IP address and network address can be specified together as an IP interface. For example:

>>> inet = ipaddress.ip_interface('123.45.67.73/27')
>>> inet.network
IPv4Network('123.45.67.64/27')
>>> inet.ip
IPv4Address('123.45.67.73')
>>>

讨论¶

The ipaddress module has classes for representing IP addresses, networks, and inter‐ faces. This can be especially useful if you want to write code that needs to manipulate network addresses in some way (e.g., parsing, printing, validating, etc.). Be aware that there is only limited interaction between the ipaddress module and other network-related modules, such as the socket library. In particular, it is usually not possible to use an instance of IPv4Address as a substitute for address string. Instead, you have to explicitly convert it using str() first. For example:

>>> a = ipaddress.ip_address('127.0.0.1')
>>> from socket import socket, AF_INET, SOCK_STREAM
>>> s = socket(AF_INET, SOCK_STREAM)
>>> s.connect((a, 8080))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: Can't convert 'IPv4Address' object to str implicitly
>>> s.connect((str(a), 8080))
>>>

See “An Introduction to the ipaddress Module” for more information and advanced usage.