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# Copyright 2014 DreamHost, LLC
#
# Author: DreamHost, LLC
#
# 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 logging
import random
import textwrap
from akanda.router.drivers import base
from akanda.router import utils
LOG = logging.getLogger(__name__)
CONF_PATH = '/etc/bird/bird6.conf'
BIRD = '/usr/local/sbin/bird'
BIRDC = '/usr/local/bin/birdc'
DEFAULT_AREA = 0
class BirdManager(base.Manager):
"""
A class to interact with BIRD, an internet routing protocol daemon.
"""
def __init__(self, root_helper='sudo'):
"""
Initializes BirdManager class.
:type root_helper: string
:param root_helper: System utility used to gain escalate privileges.
"""
super(BirdManager, self).__init__(root_helper)
def save_config(self, config, if_map):
"""
Writes config file for bird daemon.
:type config: akanda.router.models.Configuration
:param config:
:type if_map: dict
:param if_map: A (dict) mapping of generic to physical hostname, e.g.:
{'ge0': 'eth0', 'ge1': 'eth1'}
"""
config_data = build_config(config, if_map)
utils.replace_file('/tmp/bird6.conf', config_data)
utils.execute(['mv', '/tmp/bird6.conf', CONF_PATH], self.root_helper)
def restart(self):
"""
Restart the BIRD daemon using the system provided init scripts.
"""
try:
utils.execute(['/etc/init.d/bird6', 'status'], self.root_helper)
except: # pragma no cover
utils.execute(['/etc/init.d/bird6', 'start'], self.root_helper)
else: # pragma no cover
utils.execute(['/etc/init.d/bird6', 'reload'], self.root_helper)
def build_config(config, interface_map):
"""
Generate a configuration file for the BIRD daemon with interface mapping
provided by <interface_map>.
:type interface_map: dict
:param interface_map: A (dict) mapping of generic to physical hostname:
{'ge0': 'eth0', 'ge1': 'eth1'}
:rtype: str
"""
config_data = [
_build_global_config(config),
_build_kernel_config(),
_build_device_config(),
_build_static_config(config),
_build_direct_config(config, interface_map),
# _build_ospf_config(config, interface_map),
_build_bgp_config(config, interface_map),
_build_radv_config(config, interface_map),
]
return '\n'.join(config_data)
def _find_external_v4_ip(config):
"""
Determines the external IPv4 address.
:type config: akanda.router.models.Configuration
:param config:
:rtype: str
"""
v4_id = config.external_v4_id
if v4_id:
return v4_id
else: # fallback to random value
return '0.0.%d.%d' % (random.randint(0, 255), random.randint(0, 255))
def _build_global_config(config):
"""
Generate the "global" section of the BIRD daemon configuration.
:type config: akanda.router.models.Configuration
:param config:
:rtype: str
"""
retval = [
'log syslog {warning, error, info};',
'router id %s;' % _find_external_v4_ip(config),
]
return '\n'.join(retval)
def _build_kernel_config():
"""
Generate the "kernel" section of the BIRD daemon configuration.
:type config: akanda.router.models.Configuration
:param config:
:rtype: str
"""
config = """
protocol kernel {
learn;
scan time 20;
import all;
export all;
}"""
return textwrap.dedent(config).strip()
def _build_device_config():
"""
Generate the "device" section of the BIRD daemon configuration.
:type config: akanda.router.models.Configuration
:param config:
:rtype: str
"""
return 'protocol device {\n scan time 10;\n}'
def _build_static_config(config):
"""
Generate the "static" section of the BIRD daemon configuration.
:type config: akanda.router.models.Configuration
:param config:
:rtype:
"""
retval = []
# TODO: setup static routes
return '\n'.join(retval).replace('\t', ' ')
def _build_direct_config(config, interface_map):
"""
Generate the "direct" section of the BIRD daemon configuration.
:type config: akanda.router.models.Configuration
:param config:
:type interface_map: dict
:param interface_map:
:rtype:
"""
tmpl = "protocol direct {\n interface %s;\n}"
retval = tmpl % ','.join(
'"%s"' % i for i in sorted(interface_map.values())
)
return textwrap.dedent(retval)
def _build_ospf_config(config, interface_map):
"""
Generate the "ospf" section of the BIRD daemon configuration.
:type config: akanda.router.models.Configuration
:param config:
:type interface_map: dict
:param interface_map:
:rtype:
"""
retval = [
'protocol ospf {',
'\texport all;',
'\trfc1583compat yes;',
'\tarea %d {' % DEFAULT_AREA
]
for net in config.networks:
ifname = interface_map.get(net.interface.ifname)
if ifname and net.is_internal_network:
modifier = 'stub yes'
elif ifname and net.is_external_network:
modifier = 'type broadcast'
else:
continue
retval.extend([
'\t\tinterface "%s" {' % ifname,
'\t\t\tcost 10;',
'\t\t\t%s;' % modifier,
'\t\t};'
])
retval.extend([
'\t};',
'};'
])
return '\n'.join(retval).replace('\t', ' ')
def _build_bgp_config(config, interface_map):
"""
Generate the "BGP" section of the BIRD daemon configuration.
:type config: akanda.router.models.Configuration
:param config:
:type interface_map: dict
:param interface_map:
:rtype:
"""
# build the filter rule
retval = [
'filter bgp_out {',
'\tif ! (source = RTS_DEVICE) then reject;',
'\tif net ~ fc00::/7 then reject;', # filter out private addresses
]
for net in config.networks:
if not net.is_internal_network:
continue
retval.extend(
'\tif net = %s then accept;' % s.cidr
for s in net.subnets if s.cidr.version == 6 and s.gateway_ip
)
retval.extend(
[
'\telse reject;',
'}',
''
]
)
# build the bgp rule
for net in config.networks:
ifname = interface_map.get(net.interface.ifname)
if not net.is_external_network or not ifname:
continue
v6_subnets = (s for s in net.subnets
if s.cidr.version == 6 and s.gateway_ip)
for subnet in v6_subnets:
retval.extend([
'protocol bgp {',
'\tlocal as %d;' % config.asn,
'\tneighbor %s as %d;' % (subnet.gateway_ip,
config.neighbor_asn),
'\timport all;',
'\texport filter bgp_out;',
'\trr client;',
'}'
])
return '\n'.join(retval).replace('\t', ' ')
def _build_radv_config(config, interface_map):
"""
Generate the "radv" section of the BIRD daemon configuration.
:type config: akanda.router.models.Configuration
:param config:
:type interface_map: dict
:param interface_map:
:rtype:
"""
retval = [
'protocol radv {',
]
for net in config.networks:
if not net.is_tenant_network:
continue
v6_subnets = [s for s in net.subnets if s.cidr.version == 6]
if not v6_subnets:
continue
real_ifname = interface_map.get(net.interface.ifname)
if not real_ifname:
continue
retval.extend([
'\tinterface "%s" {' % real_ifname,
'\t\tmax ra interval 600;',
'\t\trdnss local yes;'
])
for subnet in v6_subnets:
retval.append('\t\tprefix %s {' % subnet.cidr)
if subnet.dhcp_enabled:
retval.append('\t\t\tautonomous off;')
retval.append('\t\t};')
if subnet.dns_nameservers:
retval.append('\t\trdnss {')
retval.append('\t\t\tlifetime mult 10;')
for ns in subnet.dns_nameservers:
retval.append('\t\t\tns %s;' % ns)
retval.append('\t\t};')
retval.append('\t};')
retval.append('}')
return '\n'.join(retval).replace('\t', ' ')