/
dhcp.py
1623 lines (1397 loc) · 67.7 KB
/
dhcp.py
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# Copyright 2012 OpenStack Foundation
# 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.
import abc
import collections
import os
import re
import shutil
import time
import netaddr
from neutron_lib.api.definitions import extra_dhcp_opt as edo_ext
from neutron_lib import constants
from neutron_lib import exceptions
from neutron_lib.utils import file as file_utils
from oslo_log import log as logging
from oslo_utils import excutils
from oslo_utils import fileutils
from oslo_utils import netutils
from oslo_utils import uuidutils
import six
from neutron._i18n import _
from neutron.agent.common import utils as agent_common_utils
from neutron.agent.linux import external_process
from neutron.agent.linux import ip_lib
from neutron.agent.linux import iptables_manager
from neutron.cmd import runtime_checks as checks
from neutron.common import utils as common_utils
from neutron.ipam import utils as ipam_utils
LOG = logging.getLogger(__name__)
UDP = 'udp'
TCP = 'tcp'
DNS_PORT = 53
DHCPV4_PORT = 67
DHCPV6_PORT = 547
METADATA_DEFAULT_PREFIX = 16
METADATA_DEFAULT_IP = '169.254.169.254'
METADATA_DEFAULT_CIDR = '%s/%d' % (METADATA_DEFAULT_IP,
METADATA_DEFAULT_PREFIX)
METADATA_PORT = 80
WIN2k3_STATIC_DNS = 249
NS_PREFIX = 'qdhcp-'
DNSMASQ_SERVICE_NAME = 'dnsmasq'
DHCP_RELEASE_TRIES = 3
DHCP_RELEASE_TRIES_SLEEP = 0.3
# this variable will be removed when neutron-lib is updated with this value
DHCP_OPT_CLIENT_ID_NUM = 61
class DictModel(dict):
"""Convert dict into an object that provides attribute access to values."""
def __init__(self, *args, **kwargs):
"""Convert dict values to DictModel values."""
super(DictModel, self).__init__(*args, **kwargs)
def needs_upgrade(item):
"""Check if `item` is a dict and needs to be changed to DictModel.
"""
return isinstance(item, dict) and not isinstance(item, DictModel)
def upgrade(item):
"""Upgrade item if it needs to be upgraded."""
if needs_upgrade(item):
return DictModel(item)
else:
return item
for key, value in self.items():
if isinstance(value, (list, tuple)):
# Keep the same type but convert dicts to DictModels
self[key] = type(value)(
(upgrade(item) for item in value)
)
elif needs_upgrade(value):
# Change dict instance values to DictModel instance values
self[key] = DictModel(value)
def __getattr__(self, name):
try:
return self[name]
except KeyError as e:
raise AttributeError(e)
def __setattr__(self, name, value):
self[name] = value
def __delattr__(self, name):
del self[name]
def __str__(self):
pairs = ['%s=%s' % (k, v) for k, v in self.items()]
return ', '.join(sorted(pairs))
class NetModel(DictModel):
def __init__(self, d):
super(NetModel, self).__init__(d)
self._ns_name = "%s%s" % (NS_PREFIX, self.id)
@property
def namespace(self):
return self._ns_name
@six.add_metaclass(abc.ABCMeta)
class DhcpBase(object):
def __init__(self, conf, network, process_monitor,
version=None, plugin=None):
self.conf = conf
self.network = network
self.process_monitor = process_monitor
self.device_manager = DeviceManager(self.conf, plugin)
self.version = version
@abc.abstractmethod
def enable(self):
"""Enables DHCP for this network."""
@abc.abstractmethod
def disable(self, retain_port=False, block=False):
"""Disable dhcp for this network."""
def restart(self):
"""Restart the dhcp service for the network."""
self.disable(retain_port=True, block=True)
self.enable()
@abc.abstractproperty
def active(self):
"""Boolean representing the running state of the DHCP server."""
@abc.abstractmethod
def reload_allocations(self):
"""Force the DHCP server to reload the assignment database."""
@classmethod
def existing_dhcp_networks(cls, conf):
"""Return a list of existing networks ids that we have configs for."""
raise NotImplementedError()
@classmethod
def check_version(cls):
"""Execute version checks on DHCP server."""
raise NotImplementedError()
@classmethod
def get_isolated_subnets(cls, network):
"""Returns a dict indicating whether or not a subnet is isolated"""
raise NotImplementedError()
@classmethod
def should_enable_metadata(cls, conf, network):
"""True if the metadata-proxy should be enabled for the network."""
raise NotImplementedError()
@six.add_metaclass(abc.ABCMeta)
class DhcpLocalProcess(DhcpBase):
PORTS = []
def __init__(self, conf, network, process_monitor, version=None,
plugin=None):
super(DhcpLocalProcess, self).__init__(conf, network, process_monitor,
version, plugin)
self.confs_dir = self.get_confs_dir(conf)
self.network_conf_dir = os.path.join(self.confs_dir, network.id)
fileutils.ensure_tree(self.network_conf_dir, mode=0o755)
@staticmethod
def get_confs_dir(conf):
return os.path.abspath(os.path.normpath(conf.dhcp_confs))
def get_conf_file_name(self, kind):
"""Returns the file name for a given kind of config file."""
return os.path.join(self.network_conf_dir, kind)
def _remove_config_files(self):
shutil.rmtree(self.network_conf_dir, ignore_errors=True)
@staticmethod
def _get_all_subnets(network):
non_local_subnets = getattr(network, 'non_local_subnets', [])
return network.subnets + non_local_subnets
def _enable_dhcp(self):
"""check if there is a subnet within the network with dhcp enabled."""
for subnet in self.network.subnets:
if subnet.enable_dhcp:
return True
return False
def enable(self):
"""Enables DHCP for this network by spawning a local process."""
try:
common_utils.wait_until_true(self._enable, timeout=300)
except common_utils.WaitTimeout:
LOG.error("Failed to start DHCP process for network %s",
self.network.id)
def _enable(self):
try:
if self.active:
self.restart()
elif self._enable_dhcp():
fileutils.ensure_tree(self.network_conf_dir, mode=0o755)
interface_name = self.device_manager.setup(self.network)
self.interface_name = interface_name
self.spawn_process()
return True
except exceptions.ProcessExecutionError as error:
LOG.debug("Spawning DHCP process for network %s failed; "
"Error: %s", self.network.id, error)
return False
def _get_process_manager(self, cmd_callback=None):
return external_process.ProcessManager(
conf=self.conf,
uuid=self.network.id,
namespace=self.network.namespace,
service=DNSMASQ_SERVICE_NAME,
default_cmd_callback=cmd_callback,
pid_file=self.get_conf_file_name('pid'),
run_as_root=True)
def disable(self, retain_port=False, block=False):
"""Disable DHCP for this network by killing the local process."""
self.process_monitor.unregister(self.network.id, DNSMASQ_SERVICE_NAME)
self._get_process_manager().disable()
if block:
common_utils.wait_until_true(lambda: not self.active)
if not retain_port:
self._destroy_namespace_and_port()
self._remove_config_files()
def _destroy_namespace_and_port(self):
try:
self.device_manager.destroy(self.network, self.interface_name)
except RuntimeError:
LOG.warning('Failed trying to delete interface: %s',
self.interface_name)
try:
ip_lib.delete_network_namespace(self.network.namespace)
except RuntimeError:
LOG.warning('Failed trying to delete namespace: %s',
self.network.namespace)
def _get_value_from_conf_file(self, kind, converter=None):
"""A helper function to read a value from one of the state files."""
file_name = self.get_conf_file_name(kind)
msg = _('Error while reading %s')
try:
with open(file_name, 'r') as f:
try:
return converter(f.read()) if converter else f.read()
except ValueError:
msg = _('Unable to convert value in %s')
except IOError:
msg = _('Unable to access %s')
LOG.debug(msg, file_name)
return None
@property
def interface_name(self):
return self._get_value_from_conf_file('interface')
@interface_name.setter
def interface_name(self, value):
interface_file_path = self.get_conf_file_name('interface')
file_utils.replace_file(interface_file_path, value)
@property
def active(self):
return self._get_process_manager().active
@abc.abstractmethod
def spawn_process(self):
pass
class Dnsmasq(DhcpLocalProcess):
# The ports that need to be opened when security policies are active
# on the Neutron port used for DHCP. These are provided as a convenience
# for users of this class.
PORTS = {constants.IP_VERSION_4:
[(UDP, DNS_PORT), (TCP, DNS_PORT), (UDP, DHCPV4_PORT)],
constants.IP_VERSION_6:
[(UDP, DNS_PORT), (TCP, DNS_PORT), (UDP, DHCPV6_PORT)],
}
_SUBNET_TAG_PREFIX = 'subnet-%s'
_PORT_TAG_PREFIX = 'port-%s'
_ID = 'id:'
_IS_DHCP_RELEASE6_SUPPORTED = None
@classmethod
def check_version(cls):
pass
@classmethod
def existing_dhcp_networks(cls, conf):
"""Return a list of existing networks ids that we have configs for."""
confs_dir = cls.get_confs_dir(conf)
try:
return [
c for c in os.listdir(confs_dir)
if uuidutils.is_uuid_like(c)
]
except OSError:
return []
def _build_cmdline_callback(self, pid_file):
# We ignore local resolv.conf if dns servers are specified
# or if local resolution is explicitly disabled.
_no_resolv = (
'--no-resolv' if self.conf.dnsmasq_dns_servers or
not self.conf.dnsmasq_local_resolv else '')
cmd = [
'dnsmasq',
'--no-hosts',
_no_resolv,
'--pid-file=%s' % pid_file,
'--dhcp-hostsfile=%s' % self.get_conf_file_name('host'),
'--addn-hosts=%s' % self.get_conf_file_name('addn_hosts'),
'--dhcp-optsfile=%s' % self.get_conf_file_name('opts'),
'--dhcp-leasefile=%s' % self.get_conf_file_name('leases'),
'--dhcp-match=set:ipxe,175',
'--dhcp-userclass=set:ipxe6,iPXE',
'--local-service',
'--bind-dynamic',
]
if not self.device_manager.driver.bridged:
cmd += [
'--bridge-interface=%s,tap*' % self.interface_name,
]
possible_leases = 0
for subnet in self._get_all_subnets(self.network):
mode = None
# if a subnet is specified to have dhcp disabled
if not subnet.enable_dhcp:
continue
if subnet.ip_version == 4:
mode = 'static'
else:
# Note(scollins) If the IPv6 attributes are not set, set it as
# static to preserve previous behavior
addr_mode = getattr(subnet, 'ipv6_address_mode', None)
ra_mode = getattr(subnet, 'ipv6_ra_mode', None)
if (addr_mode in [constants.DHCPV6_STATEFUL,
constants.DHCPV6_STATELESS] or
not addr_mode and not ra_mode):
mode = 'static'
cidr = netaddr.IPNetwork(subnet.cidr)
if self.conf.dhcp_lease_duration == -1:
lease = 'infinite'
else:
lease = '%ss' % self.conf.dhcp_lease_duration
# mode is optional and is not set - skip it
if mode:
if subnet.ip_version == 4:
cmd.append('--dhcp-range=%s%s,%s,%s,%s,%s' %
('set:', self._SUBNET_TAG_PREFIX % subnet.id,
cidr.network, mode, cidr.netmask, lease))
else:
if cidr.prefixlen < 64:
LOG.debug('Ignoring subnet %(subnet)s, CIDR has '
'prefix length < 64: %(cidr)s',
{'subnet': subnet.id, 'cidr': cidr})
continue
cmd.append('--dhcp-range=%s%s,%s,%s,%d,%s' %
('set:', self._SUBNET_TAG_PREFIX % subnet.id,
cidr.network, mode,
cidr.prefixlen, lease))
possible_leases += cidr.size
mtu = getattr(self.network, 'mtu', 0)
# Do not advertise unknown mtu
if mtu > 0:
cmd.append('--dhcp-option-force=option:mtu,%d' % mtu)
# Cap the limit because creating lots of subnets can inflate
# this possible lease cap.
cmd.append('--dhcp-lease-max=%d' %
min(possible_leases, self.conf.dnsmasq_lease_max))
if self.conf.dhcp_renewal_time > 0:
cmd.append('--dhcp-option-force=option:T1,%ds' %
self.conf.dhcp_renewal_time)
if self.conf.dhcp_rebinding_time > 0:
cmd.append('--dhcp-option-force=option:T2,%ds' %
self.conf.dhcp_rebinding_time)
cmd.append('--conf-file=%s' % self.conf.dnsmasq_config_file)
for server in self.conf.dnsmasq_dns_servers:
cmd.append('--server=%s' % server)
if self.conf.dns_domain:
cmd.append('--domain=%s' % self.conf.dns_domain)
if self.conf.dhcp_broadcast_reply:
cmd.append('--dhcp-broadcast')
if self.conf.dnsmasq_base_log_dir:
log_dir = os.path.join(
self.conf.dnsmasq_base_log_dir,
self.network.id)
try:
if not os.path.exists(log_dir):
os.makedirs(log_dir)
except OSError:
LOG.error('Error while create dnsmasq log dir: %s', log_dir)
else:
log_filename = os.path.join(log_dir, 'dhcp_dns_log')
cmd.append('--log-queries')
cmd.append('--log-dhcp')
cmd.append('--log-facility=%s' % log_filename)
return cmd
def spawn_process(self):
"""Spawn the process, if it's not spawned already."""
# we only need to generate the lease file the first time dnsmasq starts
# rather than on every reload since dnsmasq will keep the file current
self._output_init_lease_file()
self._spawn_or_reload_process(reload_with_HUP=False)
def _spawn_or_reload_process(self, reload_with_HUP):
"""Spawns or reloads a Dnsmasq process for the network.
When reload_with_HUP is True, dnsmasq receives a HUP signal,
or it's reloaded if the process is not running.
"""
self._output_config_files()
pm = self._get_process_manager(
cmd_callback=self._build_cmdline_callback)
pm.enable(reload_cfg=reload_with_HUP, ensure_active=True)
self.process_monitor.register(uuid=self.network.id,
service_name=DNSMASQ_SERVICE_NAME,
monitored_process=pm)
def _is_dhcp_release6_supported(self):
if self._IS_DHCP_RELEASE6_SUPPORTED is None:
self._IS_DHCP_RELEASE6_SUPPORTED = checks.dhcp_release6_supported()
if not self._IS_DHCP_RELEASE6_SUPPORTED:
LOG.warning("dhcp_release6 is not present on this system, "
"will not call it again.")
return self._IS_DHCP_RELEASE6_SUPPORTED
def _release_lease(self, mac_address, ip, ip_version, client_id=None,
server_id=None, iaid=None):
"""Release a DHCP lease."""
if ip_version == constants.IP_VERSION_6:
if not self._is_dhcp_release6_supported():
return
cmd = ['dhcp_release6', '--iface', self.interface_name,
'--ip', ip, '--client-id', client_id,
'--server-id', server_id, '--iaid', iaid]
else:
cmd = ['dhcp_release', self.interface_name, ip, mac_address]
if client_id:
cmd.append(client_id)
ip_wrapper = ip_lib.IPWrapper(namespace=self.network.namespace)
try:
ip_wrapper.netns.execute(cmd, run_as_root=True)
except RuntimeError as e:
# when failed to release single lease there's
# no need to propagate error further
LOG.warning('DHCP release failed for %(cmd)s. '
'Reason: %(e)s', {'cmd': cmd, 'e': e})
def _output_config_files(self):
self._output_hosts_file()
self._output_addn_hosts_file()
self._output_opts_file()
def reload_allocations(self):
"""Rebuild the dnsmasq config and signal the dnsmasq to reload."""
# If all subnets turn off dhcp, kill the process.
if not self._enable_dhcp():
self.disable()
LOG.debug('Killing dnsmasq for network since all subnets have '
'turned off DHCP: %s', self.network.id)
return
if not self.interface_name:
# we land here if above has been called and we receive port
# delete notifications for the network
LOG.debug('Agent does not have an interface on this network '
'anymore, skipping reload: %s', self.network.id)
return
self._release_unused_leases()
self._spawn_or_reload_process(reload_with_HUP=True)
LOG.debug('Reloading allocations for network: %s', self.network.id)
self.device_manager.update(self.network, self.interface_name)
def _sort_fixed_ips_for_dnsmasq(self, fixed_ips, v6_nets):
"""Sort fixed_ips so that stateless IPv6 subnets appear first.
For example, If a port with v6 extra_dhcp_opts is on a network with
IPv4 and IPv6 stateless subnets. Then dhcp host file will have
below 2 entries for same MAC,
fa:16:3e:8f:9d:65,30.0.0.5,set:aabc7d33-4874-429e-9637-436e4232d2cd
(entry for IPv4 dhcp)
fa:16:3e:8f:9d:65,set:aabc7d33-4874-429e-9637-436e4232d2cd
(entry for stateless IPv6 for v6 options)
dnsmasq internal details for processing host file entries
1) dnsmasq reads the host file from EOF.
2) So it first picks up stateless IPv6 entry,
fa:16:3e:8f:9d:65,set:aabc7d33-4874-429e-9637-436e4232d2cd
3) But dnsmasq doesn't have sufficient checks to skip this entry and
pick next entry, to process dhcp IPv4 request.
4) So dnsmasq uses this entry to process dhcp IPv4 request.
5) As there is no ip in this entry, dnsmasq logs "no address available"
and fails to send DHCPOFFER message.
As we rely on internal details of dnsmasq to understand and fix the
issue, Ihar sent a mail to dnsmasq-discuss mailing list
http://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2015q2/
009650.html
So if we reverse the order of writing entries in host file,
so that entry for stateless IPv6 comes first,
then dnsmasq can correctly fetch the IPv4 address.
"""
return sorted(
fixed_ips,
key=lambda fip: ((fip.subnet_id in v6_nets) and (
v6_nets[fip.subnet_id].ipv6_address_mode == (
constants.DHCPV6_STATELESS))),
reverse=True)
def _iter_hosts(self):
"""Iterate over hosts.
For each host on the network we yield a tuple containing:
(
port, # a DictModel instance representing the port.
alloc, # a DictModel instance of the allocated ip and subnet.
# if alloc is None, it means there is no need to allocate
# an IPv6 address because of stateless DHCPv6 network.
host_name, # Host name.
name, # Canonical hostname in the format 'hostname[.domain]'.
no_dhcp, # A flag indicating that the address doesn't need a DHCP
# IP address.
no_opts, # A flag indication that options shouldn't be written
)
"""
v6_nets = dict((subnet.id, subnet) for subnet in
self._get_all_subnets(self.network)
if subnet.ip_version == 6)
for port in self.network.ports:
fixed_ips = self._sort_fixed_ips_for_dnsmasq(port.fixed_ips,
v6_nets)
# Confirm whether Neutron server supports dns_name attribute in the
# ports API
dns_assignment = getattr(port, 'dns_assignment', None)
if dns_assignment:
dns_ip_map = {d.ip_address: d for d in dns_assignment}
for alloc in fixed_ips:
no_dhcp = False
no_opts = False
if alloc.subnet_id in v6_nets:
addr_mode = v6_nets[alloc.subnet_id].ipv6_address_mode
no_dhcp = addr_mode in (constants.IPV6_SLAAC,
constants.DHCPV6_STATELESS)
# we don't setup anything for SLAAC. It doesn't make sense
# to provide options for a client that won't use DHCP
no_opts = addr_mode == constants.IPV6_SLAAC
# If dns_name attribute is supported by ports API, return the
# dns_assignment generated by the Neutron server. Otherwise,
# generate hostname and fqdn locally (previous behaviour)
if dns_assignment:
hostname = dns_ip_map[alloc.ip_address].hostname
fqdn = dns_ip_map[alloc.ip_address].fqdn
else:
hostname = 'host-%s' % alloc.ip_address.replace(
'.', '-').replace(':', '-')
fqdn = hostname
if self.conf.dns_domain:
fqdn = '%s.%s' % (fqdn, self.conf.dns_domain)
yield (port, alloc, hostname, fqdn, no_dhcp, no_opts)
def _get_port_extra_dhcp_opts(self, port):
return getattr(port, edo_ext.EXTRADHCPOPTS, False)
def _output_init_lease_file(self):
"""Write a fake lease file to bootstrap dnsmasq.
The generated file is passed to the --dhcp-leasefile option of dnsmasq.
This is used as a bootstrapping mechanism to avoid NAKing active leases
when a dhcp server is scheduled to another agent. Using a leasefile
will also prevent dnsmasq from NAKing or ignoring renewals after a
restart.
Format is as follows:
epoch-timestamp mac_addr ip_addr hostname client-ID
"""
filename = self.get_conf_file_name('leases')
buf = six.StringIO()
LOG.debug('Building initial lease file: %s', filename)
# we make up a lease time for the database entry
if self.conf.dhcp_lease_duration == -1:
# Even with an infinite lease, a client may choose to renew a
# previous lease on reboot or interface bounce so we should have
# an entry for it.
# Dnsmasq timestamp format for an infinite lease is 0.
timestamp = 0
else:
timestamp = int(time.time()) + self.conf.dhcp_lease_duration
dhcpv4_enabled_subnet_ids = [
s.id for s in self._get_all_subnets(self.network)
if s.enable_dhcp and s.ip_version == constants.IP_VERSION_4]
for host_tuple in self._iter_hosts():
port, alloc, hostname, name, no_dhcp, no_opts = host_tuple
# don't write ip address which belongs to a dhcp disabled subnet
# or an IPv6 subnet.
if no_dhcp or alloc.subnet_id not in dhcpv4_enabled_subnet_ids:
continue
# all that matters is the mac address and IP. the hostname and
# client ID will be overwritten on the next renewal.
buf.write('%s %s %s * *\n' %
(timestamp, port.mac_address, alloc.ip_address))
contents = buf.getvalue()
file_utils.replace_file(filename, contents)
LOG.debug('Done building initial lease file %s with contents:\n%s',
filename, contents)
return filename
@staticmethod
def _format_address_for_dnsmasq(address):
# (dzyu) Check if it is legal ipv6 address, if so, need wrap
# it with '[]' to let dnsmasq to distinguish MAC address from
# IPv6 address.
if netaddr.valid_ipv6(address):
return '[%s]' % address
return address
def _output_hosts_file(self):
"""Writes a dnsmasq compatible dhcp hosts file.
The generated file is sent to the --dhcp-hostsfile option of dnsmasq,
and lists the hosts on the network which should receive a dhcp lease.
Each line in this file is in the form::
'mac_address,FQDN,ip_address'
IMPORTANT NOTE: a dnsmasq instance does not resolve hosts defined in
this file if it did not give a lease to a host listed in it (e.g.:
multiple dnsmasq instances on the same network if this network is on
multiple network nodes). This file is only defining hosts which
should receive a dhcp lease, the hosts resolution in itself is
defined by the `_output_addn_hosts_file` method.
"""
buf = six.StringIO()
filename = self.get_conf_file_name('host')
LOG.debug('Building host file: %s', filename)
dhcp_enabled_subnet_ids = [s.id for s in
self._get_all_subnets(self.network)
if s.enable_dhcp]
# NOTE(ihrachyshka): the loop should not log anything inside it, to
# avoid potential performance drop when lots of hosts are dumped
for host_tuple in self._iter_hosts():
port, alloc, hostname, name, no_dhcp, no_opts = host_tuple
if no_dhcp:
if not no_opts and self._get_port_extra_dhcp_opts(port):
buf.write('%s,%s%s\n' % (
port.mac_address,
'set:', self._PORT_TAG_PREFIX % port.id))
continue
# don't write ip address which belongs to a dhcp disabled subnet.
if alloc.subnet_id not in dhcp_enabled_subnet_ids:
continue
ip_address = self._format_address_for_dnsmasq(alloc.ip_address)
if self._get_port_extra_dhcp_opts(port):
client_id = self._get_client_id(port)
if client_id and len(port.extra_dhcp_opts) > 1:
buf.write('%s,%s%s,%s,%s,%s%s\n' %
(port.mac_address, self._ID, client_id, name,
ip_address, 'set:',
self._PORT_TAG_PREFIX % port.id))
elif client_id and len(port.extra_dhcp_opts) == 1:
buf.write('%s,%s%s,%s,%s\n' %
(port.mac_address, self._ID, client_id, name,
ip_address))
else:
buf.write('%s,%s,%s,%s%s\n' %
(port.mac_address, name, ip_address,
'set:', self._PORT_TAG_PREFIX % port.id))
else:
buf.write('%s,%s,%s\n' %
(port.mac_address, name, ip_address))
file_utils.replace_file(filename, buf.getvalue())
LOG.debug('Done building host file %s', filename)
return filename
def _get_client_id(self, port):
if self._get_port_extra_dhcp_opts(port):
for opt in port.extra_dhcp_opts:
if opt.opt_name in (edo_ext.DHCP_OPT_CLIENT_ID,
DHCP_OPT_CLIENT_ID_NUM,
str(DHCP_OPT_CLIENT_ID_NUM)):
return opt.opt_value
def _read_hosts_file_leases(self, filename):
leases = set()
try:
with open(filename) as f:
for l in f.readlines():
host = l.strip().split(',')
mac = host[0]
client_id = None
if host[1].startswith('set:'):
continue
if host[1].startswith(self._ID):
ip = host[3].strip('[]')
client_id = host[1][len(self._ID):]
else:
ip = host[2].strip('[]')
leases.add((ip, mac, client_id))
except (OSError, IOError):
LOG.debug('Error while reading hosts file %s', filename)
return leases
def _read_leases_file_leases(self, filename, ip_version=None):
"""Read dnsmasq dhcp leases file
Read information from leases file, which is needed to pass to
dhcp_release6 command line utility if some of these leases are not
needed anymore
each line in dnsmasq leases file is one of the following
* duid entry: duid server_duid
There MUST be single duid entry per file
* ipv4 entry: space separated list
- The expiration time (seconds since unix epoch) or duration
(if dnsmasq is compiled with HAVE_BROKEN_RTC) of the lease.
0 means infinite.
- The link address, in format XX-YY:YY:YY[...], where XX is the ARP
hardware type. "XX-" may be omitted for Ethernet.
- The IPv4 address
- The hostname (sent by the client or assigned by dnsmasq)
or '*' for none.
- The client identifier (colon-separated hex bytes)
or '*' for none.
* ipv6 entry: space separated list
- The expiration time or duration
- The IAID as a Big Endian decimal number, prefixed by T for
IA_TAs (temporary addresses).
- The IPv6 address
- The hostname or '*'
- The client DUID (colon-separated hex bytes) or '*' if unknown
original discussion is in dnsmasq mailing list
http://lists.thekelleys.org.uk/pipermail/\
dnsmasq-discuss/2016q2/010595.html
:param filename: leases file
:param ip_version: IP version of entries to return, or None for all
:return: dict, keys are IP(v6) addresses, values are dicts containing
iaid, client_id and server_id
"""
leases = {}
server_id = None
if os.path.exists(filename):
with open(filename) as f:
for l in f.readlines():
if l.startswith('duid'):
if not server_id:
server_id = l.strip().split()[1]
continue
else:
LOG.warning('Multiple DUID entries in %s '
'lease file, dnsmasq is possibly '
'not functioning properly',
filename)
continue
parts = l.strip().split()
if len(parts) != 5:
LOG.warning('Invalid lease entry %s found in %s '
'lease file, ignoring', parts, filename)
continue
(iaid, ip, client_id) = parts[1], parts[2], parts[4]
ip = ip.strip('[]')
if (ip_version and
netaddr.IPAddress(ip).version != ip_version):
continue
leases[ip] = {'iaid': iaid,
'client_id': client_id,
'server_id': server_id
}
return leases
def _release_unused_leases(self):
filename = self.get_conf_file_name('host')
old_leases = self._read_hosts_file_leases(filename)
leases_filename = self.get_conf_file_name('leases')
cur_leases = self._read_leases_file_leases(leases_filename)
if not cur_leases:
return
v4_leases = set()
for (k, v) in cur_leases.items():
# IPv4 leases have a MAC, IPv6 ones do not, so we must ignore
if netaddr.IPAddress(k).version == constants.IP_VERSION_4:
# treat '*' as None, see note in _read_leases_file_leases()
client_id = v['client_id']
if client_id is '*':
client_id = None
v4_leases.add((k, v['iaid'], client_id))
new_leases = set()
for port in self.network.ports:
client_id = self._get_client_id(port)
for alloc in port.fixed_ips:
new_leases.add((alloc.ip_address, port.mac_address, client_id))
# If an entry is in the leases or host file(s), but doesn't have
# a fixed IP on a corresponding neutron port, consider it stale.
entries_to_release = (v4_leases | old_leases) - new_leases
if not entries_to_release:
return
# If the VM advertises a client ID in its lease, but its not set in
# the port's Extra DHCP Opts, the lease will not be filtered above.
# Release the lease only if client ID is set in port DB and a mismatch
# Otherwise the lease is released when other ports are deleted/updated
entries_with_no_client_id = set()
for ip, mac, client_id in entries_to_release:
if client_id:
entry_no_client_id = (ip, mac, None)
if (entry_no_client_id in old_leases and
entry_no_client_id in new_leases):
entries_with_no_client_id.add((ip, mac, client_id))
entries_to_release -= entries_with_no_client_id
# Try DHCP_RELEASE_TRIES times to release a lease, re-reading the
# file each time to see if it's still there. We loop +1 times to
# check the lease file one last time before logging any remaining
# entries.
for i in range(DHCP_RELEASE_TRIES + 1):
entries_not_present = set()
for ip, mac, client_id in entries_to_release:
try:
entry = cur_leases[ip]
except KeyError:
entries_not_present.add((ip, mac, client_id))
continue
# if not the final loop, try and release
if i < DHCP_RELEASE_TRIES:
ip_version = netaddr.IPAddress(ip).version
if ip_version == constants.IP_VERSION_6:
client_id = entry['client_id']
self._release_lease(mac, ip, ip_version, client_id,
entry['server_id'], entry['iaid'])
# Remove elements that were not in the current leases file,
# no need to look for them again, and see if we're done.
entries_to_release -= entries_not_present
if not entries_to_release:
break
if i < DHCP_RELEASE_TRIES:
time.sleep(DHCP_RELEASE_TRIES_SLEEP)
cur_leases = self._read_leases_file_leases(leases_filename)
if not cur_leases:
break
else:
LOG.warning("Could not release DHCP leases for these IP "
"addresses after %d tries: %s",
DHCP_RELEASE_TRIES,
', '.join(ip for ip, m, c in entries_to_release))
def _output_addn_hosts_file(self):
"""Writes a dnsmasq compatible additional hosts file.
The generated file is sent to the --addn-hosts option of dnsmasq,
and lists the hosts on the network which should be resolved even if
the dnsmasq instance did not give a lease to the host (see the
`_output_hosts_file` method).
Each line in this file is in the same form as a standard /etc/hosts
file.
"""
buf = six.StringIO()
for host_tuple in self._iter_hosts():
port, alloc, hostname, fqdn, no_dhcp, no_opts = host_tuple
# It is compulsory to write the `fqdn` before the `hostname` in
# order to obtain it in PTR responses.
if alloc:
buf.write('%s\t%s %s\n' % (alloc.ip_address, fqdn, hostname))
addn_hosts = self.get_conf_file_name('addn_hosts')
file_utils.replace_file(addn_hosts, buf.getvalue())
return addn_hosts
def _output_opts_file(self):
"""Write a dnsmasq compatible options file."""
options, subnet_index_map = self._generate_opts_per_subnet()
options += self._generate_opts_per_port(subnet_index_map)
name = self.get_conf_file_name('opts')
file_utils.replace_file(name, '\n'.join(options))
return name
def _generate_opts_per_subnet(self):
options = []
subnets_without_nameservers = set()
if self.conf.enable_isolated_metadata or self.conf.force_metadata:
subnet_to_interface_ip = self._make_subnet_interface_ip_map()
isolated_subnets = self.get_isolated_subnets(self.network)
for subnet in self._get_all_subnets(self.network):
addr_mode = getattr(subnet, 'ipv6_address_mode', None)
segment_id = getattr(subnet, 'segment_id', None)
if (not subnet.enable_dhcp or
(subnet.ip_version == 6 and
addr_mode == constants.IPV6_SLAAC)):
continue
if subnet.dns_nameservers:
if ((subnet.ip_version == 4 and
subnet.dns_nameservers == ['0.0.0.0']) or
(subnet.ip_version == 6 and
subnet.dns_nameservers == ['::'])):
# Special case: Do not announce DNS servers
options.append(
self._format_option(
subnet.ip_version,
self._SUBNET_TAG_PREFIX % subnet.id,
'dns-server'))
else:
options.append(
self._format_option(
subnet.ip_version,
self._SUBNET_TAG_PREFIX % subnet.id,
'dns-server', ','.join(
Dnsmasq._convert_to_literal_addrs(
subnet.ip_version,
subnet.dns_nameservers))))
else:
# use the dnsmasq ip as nameservers only if there is no
# dns-server submitted by the server
# Here is something to check still
subnets_without_nameservers.add(subnet.id)
if self.conf.dns_domain and subnet.ip_version == 6:
# This should be change also
options.append(
self._format_option(
subnet.ip_version, self._SUBNET_TAG_PREFIX % subnet.id,
"domain-search", ''.join(self.conf.dns_domain)))
gateway = subnet.gateway_ip
host_routes = []
for hr in subnet.host_routes:
if hr.destination == constants.IPv4_ANY: