/usr/lib/ifupdown-multi.py is in ifupdown-multi 0.1.1.
This file is owned by root:root, with mode 0o755.
The actual contents of the file can be viewed below.
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 | #!/usr/bin/env python
# Copyright (c) 2013 by Farsight Security, Inc.
#
# 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 errno
import glob
import logging
import os
import subprocess
import sys
process_name = os.path.basename(sys.argv[0])
required_keys = (
'MODE',
'ADDRFAM',
'IFACE',
'IF_ADDRESS',
'IF_MULTI_TABLE',
'IF_MULTI_GATEWAY',
)
additional_keys = (
'IF_MULTI_GATEWAY_WEIGHT',
'IF_MULTI_PREFERRED_PREFIXES',
)
fname_prefix = '/var/run/network/ifupdown-multi.'
fname_nexthop = fname_prefix + '%(IFACE)s.nexthop.%(ADDRFAM)s'
fname_rules = fname_prefix + '%(IFACE)s.rules.%(ADDRFAM)s'
glob_nexthop = fname_prefix + '*.nexthop.%(ADDRFAM)s'
priority_magic = 25357
priority_magic_preferred = 31047
def run(cmd):
logging.debug('running command %r', cmd)
rc = subprocess.call(cmd, shell=True)
if rc != 0:
logging.critical('command %r failed with exit code %d', cmd, rc)
return rc
def mkdir(dname):
if not os.path.isdir(dname):
rc = run('mkdir %s' % dname)
if rc != 0:
raise Exception, 'unable to create directory %s' % dname
class ifupdownMulti:
def __init__(self, env):
mkdir('/var/run/network')
self.cfg = {}
for key in required_keys:
if env.has_key(key):
self.cfg[key] = env[key]
else:
raise Exception, 'missing environment variable %s' % key
for key in additional_keys:
if env.has_key(key):
if key == 'IF_MULTI_GATEWAY_WEIGHT' and self.cfg['ADDRFAM'] == 'inet6':
logging.warning('multi_gateway_weight not supported with IPv6')
else:
self.cfg[key] = env[key]
if not self.cfg['MODE'] in ('start', 'stop'):
raise Exception, 'unknown ifupdown mode %s' % self.cfg['MODE']
if self.cfg['ADDRFAM'] == 'inet':
self.cfg['ip'] = 'ip'
elif self.cfg['ADDRFAM'] == 'inet6':
self.cfg['ip'] = 'ip -6'
table_id = int(self.cfg['IF_MULTI_TABLE'])
self.cfg['PRIORITY_PREFERRED'] = priority_magic_preferred + table_id
self.cfg['PRIORITY'] = priority_magic + table_id
self.fname_nexthop = fname_nexthop % self.cfg
self.fname_rules = fname_rules % self.cfg
self.glob_nexthop = glob_nexthop % self.cfg
def dispatch(self):
if self.cfg['ADDRFAM'] in ('inet', 'inet6'):
if self.cfg['MODE'] == 'start':
self.start()
elif self.cfg['MODE'] == 'stop':
self.stop()
def flush_route_cache(self):
run('%(ip)s route flush cache' % self.cfg)
def start_rule(self, rule):
rule = rule % self.cfg
with open(self.fname_rules, 'a') as w:
w.write(rule + '\n')
run('%s rule add %s' % (self.cfg['ip'], rule))
def start_route(self, route):
route = route % self.cfg
run('%s route replace %s' % (self.cfg['ip'], route))
def restart_nexthops(self):
if self.cfg['ADDRFAM'] == 'inet':
nexthops = set()
for fname in glob.glob(self.glob_nexthop):
for line in open(fname):
nexthops.add(line.strip())
if nexthops:
nexthops = sorted(list(nexthops))
cmd = self.cfg['ip'] + ' route replace default scope global ' + ' '.join(nexthops)
run(cmd)
else:
run('%(ip)s route delete default' % self.cfg)
def start_gateway(self):
if self.cfg['ADDRFAM'] == 'inet':
self.start_route('default via %(IF_MULTI_GATEWAY)s dev %(IFACE)s table %(IF_MULTI_TABLE)s proto static')
nexthop = 'nexthop via %(IF_MULTI_GATEWAY)s dev %(IFACE)s' % self.cfg
weight = self.cfg.get('IF_MULTI_GATEWAY_WEIGHT')
if weight:
nexthop += ' weight ' + weight
elif self.cfg['ADDRFAM'] == 'inet6':
nexthop = 'default via %(IF_MULTI_GATEWAY)s src %(IF_ADDRESS)s dev %(IFACE)s' % self.cfg
run('%s route replace %s table %s proto static' % (self.cfg['ip'], nexthop, self.cfg['IF_MULTI_TABLE']))
run('%s route append %s' % (self.cfg['ip'], nexthop))
with open(self.fname_nexthop, 'w') as w:
w.write(nexthop)
w.write('\n')
self.restart_nexthops()
def stop_gateway(self):
if self.cfg['ADDRFAM'] == 'inet':
self.restart_nexthops()
elif self.cfg['ADDRFAM'] == 'inet6':
try:
with open(self.fname_nexthop, 'r') as f:
nexthop = f.readline().strip()
if nexthop:
run('%s route delete %s' % (self.cfg['ip'], nexthop))
except IOError, e:
if e.errno != errno.ENOENT:
raise
def start(self):
self.start_rule('from %(IF_ADDRESS)s table %(IF_MULTI_TABLE)s priority %(PRIORITY)s')
self.start_rule('to %(IF_ADDRESS)s table %(IF_MULTI_TABLE)s priority %(PRIORITY)s')
preferred_prefixes = self.cfg.get('IF_MULTI_PREFERRED_PREFIXES')
if preferred_prefixes:
for prefix in preferred_prefixes.split():
self.cfg['PREFIX'] = prefix
self.start_rule('to %(PREFIX)s table %(IF_MULTI_TABLE)s priority %(PRIORITY_PREFERRED)s')
self.start_gateway()
self.flush_route_cache()
def stop_rules(self):
if os.path.exists(self.fname_rules):
for line in open(self.fname_rules):
rule = line.strip()
run(self.cfg['ip'] + ' rule delete ' + rule)
try:
logging.debug('unlinking %s', self.fname_rules)
os.unlink(self.fname_rules)
except OSError:
pass
def stop(self):
run('%(ip)s route flush table %(IF_MULTI_TABLE)s' % self.cfg)
try:
logging.debug('unlinking %s', self.fname_nexthop)
os.unlink(self.fname_nexthop)
except OSError:
pass
self.stop_gateway()
self.stop_rules()
self.flush_route_cache()
def main():
if not 'IF_MULTI_TABLE' in os.environ:
sys.exit(0)
if not os.getenv('MODE') in ('start', 'stop'):
sys.exit(0)
if os.getenv('VERBOSITY') == '1':
level = logging.DEBUG
else:
level = logging.WARNING
logging.basicConfig(format=process_name+': %(levelname)s: %(message)s', level=level)
ifupdownMulti(os.environ).dispatch()
if __name__ == '__main__':
main()
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