vmware-nsx/quantum/agent/linux/ip_lib.py
Gary Kotton 0853b8ebbb Fixes order of route entries.
Fixes bug 1083238

This patch makes sure that a route entry for dnsmasq is placed first
before any others (for example the l3-agent one). This makes DHCP work
when network namespaces are disabled.

Change-Id: I241a8e30127d614f7582e10d999521f6486e5255
2012-11-27 19:52:53 +00:00

408 lines
13 KiB
Python

# vim: tabstop=4 shiftwidth=4 softtabstop=4
# Copyright 2012 OpenStack LLC
# 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.
from quantum.agent.linux import utils
from quantum.common import exceptions
LOOPBACK_DEVNAME = 'lo'
class SubProcessBase(object):
def __init__(self, root_helper=None, namespace=None):
self.root_helper = root_helper
self.namespace = namespace
def _run(self, options, command, args):
if self.namespace:
return self._as_root(options, command, args)
else:
return self._execute(options, command, args)
def _as_root(self, options, command, args, use_root_namespace=False):
if not self.root_helper:
raise exceptions.SudoRequired()
namespace = self.namespace if not use_root_namespace else None
return self._execute(options,
command,
args,
self.root_helper,
namespace)
@classmethod
def _execute(cls, options, command, args, root_helper=None,
namespace=None):
opt_list = ['-%s' % o for o in options]
if namespace:
ip_cmd = ['ip', 'netns', 'exec', namespace, 'ip']
else:
ip_cmd = ['ip']
return utils.execute(ip_cmd + opt_list + [command] + list(args),
root_helper=root_helper)
class IPWrapper(SubProcessBase):
def __init__(self, root_helper=None, namespace=None):
super(IPWrapper, self).__init__(root_helper=root_helper,
namespace=namespace)
self.netns = IpNetnsCommand(self)
def device(self, name):
return IPDevice(name, self.root_helper, self.namespace)
def get_devices(self, exclude_loopback=False):
retval = []
output = self._execute('o', 'link', ('list',),
self.root_helper, self.namespace)
for line in output.split('\n'):
if '<' not in line:
continue
tokens = line.split(':', 2)
if len(tokens) >= 3:
name = tokens[1].strip()
if exclude_loopback and name == LOOPBACK_DEVNAME:
continue
retval.append(IPDevice(name,
self.root_helper,
self.namespace))
return retval
def add_tuntap(self, name, mode='tap'):
self._as_root('', 'tuntap', ('add', name, 'mode', mode))
return IPDevice(name, self.root_helper, self.namespace)
def add_veth(self, name1, name2):
self._as_root('', 'link',
('add', name1, 'type', 'veth', 'peer', 'name', name2))
return (IPDevice(name1, self.root_helper, self.namespace),
IPDevice(name2, self.root_helper, self.namespace))
def ensure_namespace(self, name):
if not self.netns.exists(name):
ip = self.netns.add(name)
lo = ip.device(LOOPBACK_DEVNAME)
lo.link.set_up()
else:
ip = IPWrapper(self.root_helper, name)
return ip
def namespace_is_empty(self):
return not self.get_devices(exclude_loopback=True)
def garbage_collect_namespace(self):
"""Conditionally destroy the namespace if it is empty."""
if self.namespace and self.netns.exists(self.namespace):
if self.namespace_is_empty():
self.netns.delete(self.namespace)
return True
return False
def add_device_to_namespace(self, device):
if self.namespace:
device.link.set_netns(self.namespace)
@classmethod
def get_namespaces(cls, root_helper):
output = cls._execute('', 'netns', ('list',), root_helper=root_helper)
return [l.strip() for l in output.split('\n')]
class IPDevice(SubProcessBase):
def __init__(self, name, root_helper=None, namespace=None):
super(IPDevice, self).__init__(root_helper=root_helper,
namespace=namespace)
self.name = name
self.link = IpLinkCommand(self)
self.addr = IpAddrCommand(self)
self.route = IpRouteCommand(self)
def __eq__(self, other):
return (other is not None and self.name == other.name
and self.namespace == other.namespace)
def __str__(self):
return self.name
class IpCommandBase(object):
COMMAND = ''
def __init__(self, parent):
self._parent = parent
def _run(self, *args, **kwargs):
return self._parent._run(kwargs.get('options', []), self.COMMAND, args)
def _as_root(self, *args, **kwargs):
return self._parent._as_root(kwargs.get('options', []),
self.COMMAND,
args,
kwargs.get('use_root_namespace', False))
class IpDeviceCommandBase(IpCommandBase):
@property
def name(self):
return self._parent.name
class IpLinkCommand(IpDeviceCommandBase):
COMMAND = 'link'
def set_address(self, mac_address):
self._as_root('set', self.name, 'address', mac_address)
def set_mtu(self, mtu_size):
self._as_root('set', self.name, 'mtu', mtu_size)
def set_up(self):
self._as_root('set', self.name, 'up')
def set_down(self):
self._as_root('set', self.name, 'down')
def set_netns(self, namespace):
self._as_root('set', self.name, 'netns', namespace)
self._parent.namespace = namespace
def set_name(self, name):
self._as_root('set', self.name, 'name', name)
self._parent.name = name
def delete(self):
self._as_root('delete', self.name)
@property
def address(self):
return self.attributes.get('link/ether')
@property
def state(self):
return self.attributes.get('state')
@property
def mtu(self):
return self.attributes.get('mtu')
@property
def qdisc(self):
return self.attributes.get('qdisc')
@property
def qlen(self):
return self.attributes.get('qlen')
@property
def attributes(self):
return self._parse_line(self._run('show', self.name, options='o'))
def _parse_line(self, value):
if not value:
return {}
device_name, settings = value.replace("\\", '').split('>', 1)
tokens = settings.split()
keys = tokens[::2]
values = [int(v) if v.isdigit() else v for v in tokens[1::2]]
retval = dict(zip(keys, values))
return retval
class IpAddrCommand(IpDeviceCommandBase):
COMMAND = 'addr'
def add(self, ip_version, cidr, broadcast, scope='global'):
self._as_root('add',
cidr,
'brd',
broadcast,
'scope',
scope,
'dev',
self.name,
options=[ip_version])
def delete(self, ip_version, cidr):
self._as_root('del',
cidr,
'dev',
self.name,
options=[ip_version])
def flush(self):
self._as_root('flush', self.name)
def list(self, scope=None, to=None, filters=None):
if filters is None:
filters = []
retval = []
if scope:
filters += ['scope', scope]
if to:
filters += ['to', to]
for line in self._run('show', self.name, *filters).split('\n'):
line = line.strip()
if not line.startswith('inet'):
continue
parts = line.split()
if parts[0] == 'inet6':
version = 6
scope = parts[3]
broadcast = '::'
else:
version = 4
broadcast = parts[3]
scope = parts[5]
retval.append(dict(cidr=parts[1],
broadcast=broadcast,
scope=scope,
ip_version=version,
dynamic=('dynamic' == parts[-1])))
return retval
class IpRouteCommand(IpDeviceCommandBase):
COMMAND = 'route'
def add_gateway(self, gateway, metric=None):
args = ['add', 'default', 'via', gateway]
if metric:
args += ['metric', metric]
args += ['dev', self.name]
self._as_root(*args)
def delete_gateway(self, gateway):
self._as_root('del',
'default',
'via',
gateway,
'dev',
self.name)
def get_gateway(self, scope=None, filters=None):
if filters is None:
filters = []
retval = None
if scope:
filters += ['scope', scope]
route_list_lines = self._run('list', 'dev', self.name,
*filters).split('\n')
default_route_line = next((x.strip() for x in
route_list_lines if
x.strip().startswith('default')), None)
if default_route_line:
gateway_index = 2
parts = default_route_line.split()
retval = dict(gateway=parts[gateway_index])
metric_index = 4
parts_has_metric = (len(parts) > metric_index)
if parts_has_metric:
retval.update(metric=int(parts[metric_index]))
return retval
def pullup_route(self, interface_name):
"""
Ensures that the route entry for the interface is before all
others on the same subnet.
"""
device_list = []
device_route_list_lines = self._run('list', 'proto', 'kernel',
'dev', interface_name).split('\n')
for device_route_line in device_route_list_lines:
try:
subnet = device_route_line.split()[0]
except:
continue
subnet_route_list_lines = self._run('list', 'proto', 'kernel',
'match', subnet).split('\n')
for subnet_route_line in subnet_route_list_lines:
i = iter(subnet_route_line.split())
while(i.next() != 'dev'):
pass
device = i.next()
try:
while(i.next() != 'src'):
pass
src = i.next()
except:
src = ''
if device != interface_name:
device_list.append((device, src))
else:
break
for (device, src) in device_list:
self._as_root('del', subnet, 'dev', device)
if (src != ''):
self._as_root('append', subnet, 'proto', 'kernel',
'src', src, 'dev', device)
else:
self._as_root('append', subnet, 'proto', 'kernel',
'dev', device)
class IpNetnsCommand(IpCommandBase):
COMMAND = 'netns'
def add(self, name):
self._as_root('add', name, use_root_namespace=True)
return IPWrapper(self._parent.root_helper, name)
def delete(self, name):
self._as_root('delete', name, use_root_namespace=True)
def execute(self, cmds, addl_env={}, check_exit_code=True):
if not self._parent.root_helper:
raise exceptions.SudoRequired()
elif not self._parent.namespace:
raise Exception(_('No namespace defined for parent'))
else:
return utils.execute(
['%s=%s' % pair for pair in addl_env.items()] +
['ip', 'netns', 'exec', self._parent.namespace] + list(cmds),
root_helper=self._parent.root_helper,
check_exit_code=check_exit_code)
def exists(self, name):
output = self._as_root('list', options='o', use_root_namespace=True)
for line in output.split('\n'):
if name == line.strip():
return True
return False
def device_exists(device_name, root_helper=None, namespace=None):
try:
address = IPDevice(device_name, root_helper, namespace).link.address
except RuntimeError:
return False
return bool(address)