c939aee8d6
Previously neutron was keeping track of dhcp lease time in order to ensure it didn't hand out an ip address that was already leased. This patch removes that logic and instead leverages the dhcp_release utility. This allows us to reuse ip addresses immediately after a port is deleted. This patch also bumps the lease time to 24 hours instead of 2 minutes with reduces the amount of dhcp traffic. DocImpact There is a DocImpact for this bug related to the upgrade path. One should first upgrade their dhcp-agents. Then wait till the dhcp_lease time has expired. Lastly, update neutron-server in order to avoid the case where an instance is deleted and the dnsmasq process has not released the lease and neturon allocates that ip to a new port. Fixes bug: 1202392 Implements blueprint: remove-dhcp-lease Change-Id: Ifcb4f093c92904ceb896438987d53e692eb7fb26
479 lines
16 KiB
Python
479 lines
16 KiB
Python
# vim: tabstop=4 shiftwidth=4 softtabstop=4
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# Copyright 2012 OpenStack Foundation
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# All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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import abc
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import os
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import re
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import shutil
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import socket
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import StringIO
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import sys
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import netaddr
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from oslo.config import cfg
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from neutron.agent.linux import ip_lib
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from neutron.agent.linux import utils
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from neutron.openstack.common import jsonutils
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from neutron.openstack.common import log as logging
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from neutron.openstack.common import uuidutils
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LOG = logging.getLogger(__name__)
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OPTS = [
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cfg.StrOpt('dhcp_confs',
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default='$state_path/dhcp',
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help=_('Location to store DHCP server config files')),
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cfg.StrOpt('dhcp_domain',
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default='openstacklocal',
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help=_('Domain to use for building the hostnames')),
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cfg.StrOpt('dnsmasq_config_file',
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default='',
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help=_('Override the default dnsmasq settings with this file')),
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cfg.StrOpt('dnsmasq_dns_server',
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help=_('Use another DNS server before any in '
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'/etc/resolv.conf.')),
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]
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IPV4 = 4
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IPV6 = 6
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UDP = 'udp'
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TCP = 'tcp'
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DNS_PORT = 53
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DHCPV4_PORT = 67
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DHCPV6_PORT = 547
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METADATA_DEFAULT_IP = '169.254.169.254'
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WIN2k3_STATIC_DNS = 249
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class DhcpBase(object):
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__metaclass__ = abc.ABCMeta
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def __init__(self, conf, network, root_helper='sudo',
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device_delegate=None, namespace=None, version=None):
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self.conf = conf
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self.network = network
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self.root_helper = root_helper
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self.device_delegate = device_delegate
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self.namespace = namespace
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self.version = version
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@abc.abstractmethod
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def enable(self):
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"""Enables DHCP for this network."""
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@abc.abstractmethod
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def disable(self, retain_port=False):
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"""Disable dhcp for this network."""
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def restart(self):
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"""Restart the dhcp service for the network."""
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self.disable(retain_port=True)
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self.enable()
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@abc.abstractproperty
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def active(self):
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"""Boolean representing the running state of the DHCP server."""
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@abc.abstractmethod
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def release_lease(self, mac_address, removed_ips):
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"""Release a DHCP lease."""
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@abc.abstractmethod
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def reload_allocations(self):
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"""Force the DHCP server to reload the assignment database."""
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@classmethod
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def existing_dhcp_networks(cls, conf, root_helper):
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"""Return a list of existing networks ids that we have configs for."""
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raise NotImplementedError
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@classmethod
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def check_version(cls):
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"""Execute version checks on DHCP server."""
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raise NotImplementedError
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class DhcpLocalProcess(DhcpBase):
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PORTS = []
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def _enable_dhcp(self):
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"""check if there is a subnet within the network with dhcp enabled."""
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for subnet in self.network.subnets:
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if subnet.enable_dhcp:
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return True
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return False
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def enable(self):
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"""Enables DHCP for this network by spawning a local process."""
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interface_name = self.device_delegate.setup(self.network,
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reuse_existing=True)
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if self.active:
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self.restart()
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elif self._enable_dhcp():
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self.interface_name = interface_name
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self.spawn_process()
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def disable(self, retain_port=False):
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"""Disable DHCP for this network by killing the local process."""
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pid = self.pid
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if self.active:
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cmd = ['kill', '-9', pid]
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utils.execute(cmd, self.root_helper)
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if not retain_port:
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self.device_delegate.destroy(self.network, self.interface_name)
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elif pid:
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LOG.debug(_('DHCP for %(net_id)s pid %(pid)d is stale, ignoring '
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'command'), {'net_id': self.network.id, 'pid': pid})
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else:
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LOG.debug(_('No DHCP started for %s'), self.network.id)
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self._remove_config_files()
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def _remove_config_files(self):
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confs_dir = os.path.abspath(os.path.normpath(self.conf.dhcp_confs))
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conf_dir = os.path.join(confs_dir, self.network.id)
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shutil.rmtree(conf_dir, ignore_errors=True)
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def get_conf_file_name(self, kind, ensure_conf_dir=False):
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"""Returns the file name for a given kind of config file."""
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confs_dir = os.path.abspath(os.path.normpath(self.conf.dhcp_confs))
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conf_dir = os.path.join(confs_dir, self.network.id)
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if ensure_conf_dir:
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if not os.path.isdir(conf_dir):
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os.makedirs(conf_dir, 0o755)
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return os.path.join(conf_dir, kind)
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def _get_value_from_conf_file(self, kind, converter=None):
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"""A helper function to read a value from one of the state files."""
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file_name = self.get_conf_file_name(kind)
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msg = _('Error while reading %s')
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try:
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with open(file_name, 'r') as f:
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try:
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return converter and converter(f.read()) or f.read()
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except ValueError:
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msg = _('Unable to convert value in %s')
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except IOError:
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msg = _('Unable to access %s')
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LOG.debug(msg % file_name)
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return None
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@property
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def pid(self):
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"""Last known pid for the DHCP process spawned for this network."""
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return self._get_value_from_conf_file('pid', int)
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@property
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def active(self):
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pid = self.pid
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if pid is None:
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return False
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cmd = ['cat', '/proc/%s/cmdline' % pid]
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try:
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return self.network.id in utils.execute(cmd, self.root_helper)
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except RuntimeError:
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return False
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@property
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def interface_name(self):
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return self._get_value_from_conf_file('interface')
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@interface_name.setter
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def interface_name(self, value):
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interface_file_path = self.get_conf_file_name('interface',
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ensure_conf_dir=True)
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utils.replace_file(interface_file_path, value)
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@abc.abstractmethod
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def spawn_process(self):
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pass
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class Dnsmasq(DhcpLocalProcess):
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# The ports that need to be opened when security policies are active
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# on the Neutron port used for DHCP. These are provided as a convenience
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# for users of this class.
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PORTS = {IPV4: [(UDP, DNS_PORT), (TCP, DNS_PORT), (UDP, DHCPV4_PORT)],
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IPV6: [(UDP, DNS_PORT), (TCP, DNS_PORT), (UDP, DHCPV6_PORT)],
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}
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_TAG_PREFIX = 'tag%d'
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NEUTRON_NETWORK_ID_KEY = 'NEUTRON_NETWORK_ID'
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NEUTRON_RELAY_SOCKET_PATH_KEY = 'NEUTRON_RELAY_SOCKET_PATH'
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MINIMUM_VERSION = 2.59
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@classmethod
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def check_version(cls):
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ver = 0
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try:
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cmd = ['dnsmasq', '--version']
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out = utils.execute(cmd)
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ver = re.findall("\d+.\d+", out)[0]
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is_valid_version = float(ver) >= cls.MINIMUM_VERSION
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if not is_valid_version:
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LOG.warning(_('FAILED VERSION REQUIREMENT FOR DNSMASQ. '
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'DHCP AGENT MAY NOT RUN CORRECTLY! '
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'Please ensure that its version is %s '
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'or above!'), cls.MINIMUM_VERSION)
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except (OSError, RuntimeError, IndexError, ValueError):
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LOG.warning(_('Unable to determine dnsmasq version. '
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'Please ensure that its version is %s '
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'or above!'), cls.MINIMUM_VERSION)
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return float(ver)
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@classmethod
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def existing_dhcp_networks(cls, conf, root_helper):
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"""Return a list of existing networks ids that we have configs for."""
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confs_dir = os.path.abspath(os.path.normpath(conf.dhcp_confs))
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class FakeNetwork:
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def __init__(self, net_id):
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self.id = net_id
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return [
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c for c in os.listdir(confs_dir)
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if (uuidutils.is_uuid_like(c) and
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cls(conf, FakeNetwork(c), root_helper).active)
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]
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def spawn_process(self):
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"""Spawns a Dnsmasq process for the network."""
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env = {
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self.NEUTRON_NETWORK_ID_KEY: self.network.id,
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}
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cmd = [
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'dnsmasq',
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'--no-hosts',
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'--no-resolv',
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'--strict-order',
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'--bind-interfaces',
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'--interface=%s' % self.interface_name,
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'--except-interface=lo',
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'--pid-file=%s' % self.get_conf_file_name(
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'pid', ensure_conf_dir=True),
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#TODO (mark): calculate value from cidr (defaults to 150)
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#'--dhcp-lease-max=%s' % ?,
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'--dhcp-hostsfile=%s' % self._output_hosts_file(),
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'--dhcp-optsfile=%s' % self._output_opts_file(),
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'--leasefile-ro',
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]
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for i, subnet in enumerate(self.network.subnets):
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# if a subnet is specified to have dhcp disabled
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if not subnet.enable_dhcp:
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continue
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if subnet.ip_version == 4:
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mode = 'static'
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else:
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# TODO(mark): how do we indicate other options
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# ra-only, slaac, ra-nameservers, and ra-stateless.
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mode = 'static'
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if self.version >= self.MINIMUM_VERSION:
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set_tag = 'set:'
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else:
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set_tag = ''
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cmd.append('--dhcp-range=%s%s,%s,%s,%ss' %
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(set_tag, self._TAG_PREFIX % i,
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netaddr.IPNetwork(subnet.cidr).network,
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mode,
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self.conf.dhcp_lease_duration))
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cmd.append('--conf-file=%s' % self.conf.dnsmasq_config_file)
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if self.conf.dnsmasq_dns_server:
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cmd.append('--server=%s' % self.conf.dnsmasq_dns_server)
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if self.conf.dhcp_domain:
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cmd.append('--domain=%s' % self.conf.dhcp_domain)
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if self.namespace:
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ip_wrapper = ip_lib.IPWrapper(self.root_helper, self.namespace)
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ip_wrapper.netns.execute(cmd, addl_env=env)
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else:
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# For normal sudo prepend the env vars before command
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cmd = ['%s=%s' % pair for pair in env.items()] + cmd
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utils.execute(cmd, self.root_helper)
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def release_lease(self, mac_address, removed_ips):
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"""Release a DHCP lease."""
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for ip in removed_ips or []:
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cmd = ['dhcp_release', self.interface_name, ip, mac_address]
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if self.namespace:
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ip_wrapper = ip_lib.IPWrapper(self.root_helper, self.namespace)
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ip_wrapper.netns.execute(cmd)
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else:
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utils.execute(cmd, self.root_helper)
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def reload_allocations(self):
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"""Rebuild the dnsmasq config and signal the dnsmasq to reload."""
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# If all subnets turn off dhcp, kill the process.
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if not self._enable_dhcp():
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self.disable()
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LOG.debug(_('Killing dhcpmasq for network since all subnets have '
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'turned off DHCP: %s'), self.network.id)
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return
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self._output_hosts_file()
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self._output_opts_file()
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if self.active:
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cmd = ['kill', '-HUP', self.pid]
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utils.execute(cmd, self.root_helper)
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else:
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LOG.debug(_('Pid %d is stale, relaunching dnsmasq'), self.pid)
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LOG.debug(_('Reloading allocations for network: %s'), self.network.id)
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def _output_hosts_file(self):
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"""Writes a dnsmasq compatible hosts file."""
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r = re.compile('[:.]')
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buf = StringIO.StringIO()
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for port in self.network.ports:
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for alloc in port.fixed_ips:
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name = 'host-%s.%s' % (r.sub('-', alloc.ip_address),
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self.conf.dhcp_domain)
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buf.write('%s,%s,%s\n' %
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(port.mac_address, name, alloc.ip_address))
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name = self.get_conf_file_name('host')
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utils.replace_file(name, buf.getvalue())
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return name
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def _output_opts_file(self):
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"""Write a dnsmasq compatible options file."""
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if self.conf.enable_isolated_metadata:
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subnet_to_interface_ip = self._make_subnet_interface_ip_map()
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options = []
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for i, subnet in enumerate(self.network.subnets):
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if not subnet.enable_dhcp:
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continue
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if subnet.dns_nameservers:
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options.append(
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self._format_option(i, 'dns-server',
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','.join(subnet.dns_nameservers)))
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gateway = subnet.gateway_ip
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host_routes = []
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for hr in subnet.host_routes:
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if hr.destination == "0.0.0.0/0":
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gateway = hr.nexthop
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else:
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host_routes.append("%s,%s" % (hr.destination, hr.nexthop))
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# Add host routes for isolated network segments
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enable_metadata = (
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self.conf.enable_isolated_metadata
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and not subnet.gateway_ip
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and subnet.ip_version == 4)
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if enable_metadata:
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subnet_dhcp_ip = subnet_to_interface_ip[subnet.id]
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host_routes.append(
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'%s/32,%s' % (METADATA_DEFAULT_IP, subnet_dhcp_ip)
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)
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if host_routes:
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options.append(
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self._format_option(i, 'classless-static-route',
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','.join(host_routes)))
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options.append(
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self._format_option(i, WIN2k3_STATIC_DNS,
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','.join(host_routes)))
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if subnet.ip_version == 4:
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if gateway:
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options.append(self._format_option(i, 'router', gateway))
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else:
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options.append(self._format_option(i, 'router'))
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name = self.get_conf_file_name('opts')
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utils.replace_file(name, '\n'.join(options))
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return name
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def _make_subnet_interface_ip_map(self):
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ip_dev = ip_lib.IPDevice(
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self.interface_name,
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self.root_helper,
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self.namespace
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)
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subnet_lookup = dict(
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(netaddr.IPNetwork(subnet.cidr), subnet.id)
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for subnet in self.network.subnets
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)
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retval = {}
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for addr in ip_dev.addr.list():
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ip_net = netaddr.IPNetwork(addr['cidr'])
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if ip_net in subnet_lookup:
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retval[subnet_lookup[ip_net]] = addr['cidr'].split('/')[0]
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return retval
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def _format_option(self, index, option, *args):
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"""Format DHCP option by option name or code."""
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if self.version >= self.MINIMUM_VERSION:
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set_tag = 'tag:'
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else:
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set_tag = ''
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option = str(option)
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if not option.isdigit():
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option = 'option:%s' % option
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return ','.join((set_tag + self._TAG_PREFIX % index,
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option) + args)
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@classmethod
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def lease_update(cls):
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network_id = os.environ.get(cls.NEUTRON_NETWORK_ID_KEY)
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dhcp_relay_socket = os.environ.get(cls.NEUTRON_RELAY_SOCKET_PATH_KEY)
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action = sys.argv[1]
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if action not in ('add', 'del', 'old'):
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sys.exit()
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mac_address = sys.argv[2]
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ip_address = sys.argv[3]
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if action == 'del':
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lease_remaining = 0
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else:
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lease_remaining = int(os.environ.get('DNSMASQ_TIME_REMAINING', 0))
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data = dict(network_id=network_id, mac_address=mac_address,
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ip_address=ip_address, lease_remaining=lease_remaining)
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if os.path.exists(dhcp_relay_socket):
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sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
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sock.connect(dhcp_relay_socket)
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sock.send(jsonutils.dumps(data))
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sock.close()
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