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#!/usr/bin/env python3
#
# Copyright (C) 2017 VyOS maintainers and contributors
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 or later as
# published by the Free Software Foundation.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
#
#
import sys
import os
import fnmatch
import jinja2
from vyos.config import Config
from vyos import ConfigError
config_file = r'/etc/default/udp-broadcast-relay'
config_tmpl = """
### Autogenerated by bcast_relay.py ###
# UDP broadcast relay configuration for instance {{ id }}
{%- if description %}
# Comment: {{ description }}
{% endif -%}
DAEMON_ARGS="{% if address %}-s {{ address }} {% endif %}{{ id }} {{ port }} {{ interfaces | join(' ') }}"
"""
default_config_data = {
'disabled': False,
'instances': []
}
def get_config():
relay = default_config_data
conf = Config()
if not conf.exists('service broadcast-relay'):
return None
else:
conf.set_level('service broadcast-relay')
# Service can be disabled by user
if conf.exists('disable'):
relay['disabled'] = True
return relay
# Parse configuration of each individual instance
if conf.exists('id'):
for id in conf.list_nodes('id'):
conf.set_level('service broadcast-relay id {0}'.format(id))
config = {
'id': id,
'disabled': False,
'address': '',
'description': '',
'interfaces': [],
'port': ''
}
# Check if individual broadcast relay service is disabled
if conf.exists('disable'):
config['disabled'] = True
# Source IP of forwarded packets, if empty original senders address is used
if conf.exists('address'):
config['address'] = conf.return_value('address')
# A description for each individual broadcast relay service
if conf.exists('description'):
config['description'] = conf.return_value('description')
# UDP port to listen on for broadcast frames
if conf.exists('port'):
config['port'] = conf.return_value('port')
# Network interfaces to listen on for broadcast frames to be relayed
if conf.exists('interface'):
config['interfaces'] = conf.return_values('interface')
relay['instances'].append(config)
return relay
def verify(relay):
if relay is None:
return None
if relay['disabled']:
return None
for r in relay['instances']:
# we don't have to check this instance when it's disabled
if r['disabled']:
continue
# we certainly require a UDP port to listen to
if not r['port']:
raise ConfigError('UDP broadcast relay "{0}" requires a port number'.format(r['id']))
# Relaying data without two interface is kinda senseless ...
if len(r['interfaces']) < 2:
raise ConfigError('UDP broadcast relay "id {0}" requires at least 2 interfaces'.format(r['id']))
return None
def generate(relay):
if relay is None:
return None
config_dir = os.path.dirname(config_file)
config_filename = os.path.basename(config_file)
active_configs = []
for config in fnmatch.filter(os.listdir(config_dir), config_filename + '*'):
# determine prefix length to identify service instance
prefix_len = len(config_filename)
active_configs.append(config[prefix_len:])
# sort our list
active_configs.sort()
# delete old configuration files
for id in active_configs[:]:
if os.path.exists(config_file + id):
os.unlink(config_file + id)
# If the service is disabled, we can bail out here
if relay['disabled']:
print('Warning: UDP broadcast relay service will be deactivated because it is disabled')
return None
for r in relay['instances']:
# Skip writing instance config when it's disabled
if r['disabled']:
continue
# configuration filename contains instance id
file = config_file + str(r['id'])
tmpl = jinja2.Template(config_tmpl)
config_text = tmpl.render(r)
with open(file, 'w') as f:
f.write(config_text)
return None
def apply(relay):
# first stop all running services
os.system('sudo systemctl stop udp-broadcast-relay@{1..99}')
if (relay is None) or relay['disabled']:
return None
# start only required service instances
for r in relay['instances']:
# Don't start individual instance when it's disabled
if r['disabled']:
continue
os.system('sudo systemctl start udp-broadcast-relay@{0}'.format(r['id']))
return None
if __name__ == '__main__':
try:
c = get_config()
verify(c)
generate(c)
apply(c)
except ConfigError as e:
print(e)
sys.exit(1)
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