get_interfaces.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# Get a list of network interfaces on Linux
# Copyright © 2015 Jean Nassar

# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the "Software"),
# to deal in the Software without restriction, including without limitation
# the rights to use, copy, modify, merge, publish, distribute, sublicense,
# and/or sell copies of the Software, and to permit persons to whom the
# Software is furnished to do so, subject to the following conditions:

# The above copyright notice and this permission notice shall be included
# in all copies or substantial portions of the Software.

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
# OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
# IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
# DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
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# OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
"""
Get a list of network interfaces on Linux.

This code is compatible with Python versions 2 and 3.

"""
from collections import namedtuple
import re
import subprocess


def get_interfaces(external=False, ip=False):
    """
    Get a list of network interfaces on Linux.

    To access the MAC address and/or the IP address, set the relevant keyword
    arguments to True.

    Parameters
    ----------
    external : bool, optional
        Only show external interfaces, and ignore virtual (e.g. loopback)
        devices, and return their MAC addresses.
    ip : bool, optional
        Only show interfaces which are UP and have an IP address, and return
        their IPv4 addresses.

    Returns
    -------
    interfaces
        list of str containing the interface name by default, or list of
        namedtuple containing `name`, `mac`, and `ip` as requested.

    Examples
    --------
    >>> print(get_interfaces())
    ['eth0', 'lo', 'wlan0']
    >>> print(get_interfaces(external=True))
    [Interface(name='eth0', mac='a0:b1:c2:d3:e4:f5'), Interface(name='wlan0', ma
    c='f5:e4:d3:c2:b1:a0')]
    >>> print(get_interfaces(ip=True))
    [Interface(name='lo', ip='127.0.0.1'), Interface(name='wlan0', ip='192.168.1
    1.2')]
    >>> print(get_interfaces(external=True, ip=True))
    [Interface(name='wlan0', mac='f5:e4:d3:c2:b1:a0', ip='192.168.11.2')]

    """
    name_pattern = "^(\w+)\s"
    mac_pattern = ".*?HWaddr[ ]([0-9A-Fa-f:]{17})" if external else ""
    ip_pattern = ".*?\n\s+inet[ ]addr:((?:\d+\.){3}\d+)" if ip else ""
    pattern = re.compile("".join((name_pattern, mac_pattern, ip_pattern)),
                         flags=re.MULTILINE)

    ifconfig = subprocess.check_output("ifconfig").decode()
    interfaces = pattern.findall(ifconfig)
    if external or ip:
        Interface = namedtuple("Interface", "name {mac} {ip}".format(
            mac="mac" if external else "",
            ip="ip" if ip else ""))
        return [Interface(*interface) for interface in interfaces]
    else:
        return interfaces


if __name__ == "__main__":
    interfaces = get_interfaces(external=True, ip=True)
    for interface in interfaces:
        print("{name}: {ip}".format(name=interface.name, ip=interface.ip))