/usr/lib/python2.7/dist-packages/google_compute_engine/network_utils.py is in python-google-compute-engine 20180129+dfsg1-0ubuntu3.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 | #!/usr/bin/python
# Copyright 2016 Google Inc. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Utilities for configuring IP address forwarding."""
import logging
import os
import re
try:
import netifaces
except ImportError:
netifaces = None
MAC_REGEX = re.compile(r'\A([0-9A-Fa-f]{2}[:]){5}([0-9A-Fa-f]{2})\Z')
class NetworkUtils(object):
"""System network Ethernet interface utilities."""
def __init__(self, logger=logging):
"""Constructor.
Args:
logger: logger object, used to write to SysLog and serial port.
"""
self.logger = logger
self.interfaces = self._CreateInterfaceMap()
def _CreateInterfaceMap(self):
"""Generate a dictionary mapping MAC address to Ethernet interfaces.
Returns:
dict, string MAC addresses mapped to the string network interface name.
"""
if netifaces:
return self._CreateInterfaceMapNetifaces()
else:
return self._CreateInterfaceMapSysfs()
def _CreateInterfaceMapSysfs(self):
"""Generate a dictionary mapping MAC address to Ethernet interfaces.
Returns:
dict, string MAC addresses mapped to the string network interface name.
"""
interfaces = {}
for interface in os.listdir('/sys/class/net'):
try:
mac_address = open(
'/sys/class/net/%s/address' % interface).read().strip()
except (IOError, OSError) as e:
message = 'Unable to determine MAC address for %s. %s.'
self.logger.warning(message, interface, str(e))
else:
interfaces[mac_address] = interface
return interfaces
def _CreateInterfaceMapNetifaces(self):
"""Generate a dictionary mapping MAC address to Ethernet interfaces.
Returns:
dict, string MAC addresses mapped to the string network interface name.
"""
interfaces = {}
for interface in netifaces.interfaces():
af_link = netifaces.ifaddresses(interface).get(netifaces.AF_LINK, [])
mac_address = next(iter(af_link), {}).get('addr', '')
# In some systems this field can come with an empty string or with the
# name of the interface when there is no MAC address associated with it.
# Check the regex to be sure.
if MAC_REGEX.match(mac_address):
interfaces[mac_address] = interface
else:
message = 'Unable to determine MAC address for %s.'
self.logger.warning(message, interface)
return interfaces
def GetNetworkInterface(self, mac_address):
"""Get the name of the network interface associated with a MAC address.
Args:
mac_address: string, the hardware address of the network interface.
Returns:
string, the network interface associated with a MAC address or None.
"""
return self.interfaces.get(mac_address)
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