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host_name.py
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host_name.py
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#!/usr/bin/env python3
#
# Copyright (C) 2018-2021 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 re
import sys
import copy
import vyos.util
import vyos.hostsd_client
from vyos import ConfigError
from vyos.config import Config
from vyos.ifconfig import Section
from vyos.template import is_ip
from vyos.util import cmd
from vyos.util import call
from vyos.util import process_named_running
from vyos import airbag
airbag.enable()
default_config_data = {
'hostname': 'vyos',
'domain_name': '',
'domain_search': [],
'nameserver': [],
'nameservers_dhcp_interfaces': {},
'static_host_mapping': {}
}
hostsd_tag = 'system'
def get_config(config=None):
if config:
conf = config
else:
conf = Config()
hosts = copy.deepcopy(default_config_data)
hosts['hostname'] = conf.return_value(['system', 'host-name'])
# This may happen if the config is not loaded yet,
# e.g. if run by cloud-init
if not hosts['hostname']:
hosts['hostname'] = default_config_data['hostname']
if conf.exists(['system', 'domain-name']):
hosts['domain_name'] = conf.return_value(['system', 'domain-name'])
hosts['domain_search'].append(hosts['domain_name'])
for search in conf.return_values(['system', 'domain-search', 'domain']):
hosts['domain_search'].append(search)
if conf.exists(['system', 'name-server']):
for ns in conf.return_values(['system', 'name-server']):
if is_ip(ns):
hosts['nameserver'].append(ns)
else:
tmp = ''
if_type = Section.section(ns)
if conf.exists(['interfaces', if_type, ns, 'address']):
tmp = conf.return_values(['interfaces', if_type, ns, 'address'])
hosts['nameservers_dhcp_interfaces'].update({ ns : tmp })
# system static-host-mapping
for hn in conf.list_nodes(['system', 'static-host-mapping', 'host-name']):
hosts['static_host_mapping'][hn] = {}
hosts['static_host_mapping'][hn]['address'] = conf.return_values(['system', 'static-host-mapping', 'host-name', hn, 'inet'])
hosts['static_host_mapping'][hn]['aliases'] = conf.return_values(['system', 'static-host-mapping', 'host-name', hn, 'alias'])
return hosts
def verify(hosts):
if hosts is None:
return None
# pattern $VAR(@) "^[[:alnum:]][-.[:alnum:]]*[[:alnum:]]$" ; "invalid host name $VAR(@)"
hostname_regex = re.compile("^[A-Za-z0-9][-.A-Za-z0-9]*[A-Za-z0-9]$")
if not hostname_regex.match(hosts['hostname']):
raise ConfigError('Invalid host name ' + hosts["hostname"])
# pattern $VAR(@) "^.{1,63}$" ; "invalid host-name length"
length = len(hosts['hostname'])
if length < 1 or length > 63:
raise ConfigError(
'Invalid host-name length, must be less than 63 characters')
all_static_host_mapping_addresses = []
# static mappings alias hostname
for host, hostprops in hosts['static_host_mapping'].items():
if not hostprops['address']:
raise ConfigError(f'IP address required for static-host-mapping "{host}"')
all_static_host_mapping_addresses.append(hostprops['address'])
for a in hostprops['aliases']:
if not hostname_regex.match(a) and len(a) != 0:
raise ConfigError(f'Invalid alias "{a}" in static-host-mapping "{host}"')
for interface, interface_config in hosts['nameservers_dhcp_interfaces'].items():
# Warnin user if interface does not have DHCP or DHCPv6 configured
if not set(interface_config).intersection(['dhcp', 'dhcpv6']):
print(f'WARNING: "{interface}" is not a DHCP interface but uses DHCP name-server option!')
return None
def generate(config):
pass
def apply(config):
if config is None:
return None
## Send the updated data to vyos-hostsd
try:
hc = vyos.hostsd_client.Client()
hc.set_host_name(config['hostname'], config['domain_name'])
hc.delete_search_domains([hostsd_tag])
if config['domain_search']:
hc.add_search_domains({hostsd_tag: config['domain_search']})
hc.delete_name_servers([hostsd_tag])
if config['nameserver']:
hc.add_name_servers({hostsd_tag: config['nameserver']})
# add our own tag's (system) nameservers and search to resolv.conf
hc.delete_name_server_tags_system(hc.get_name_server_tags_system())
hc.add_name_server_tags_system([hostsd_tag])
# this will add the dhcp client nameservers to resolv.conf
for intf in config['nameservers_dhcp_interfaces']:
hc.add_name_server_tags_system([f'dhcp-{intf}', f'dhcpv6-{intf}'])
hc.delete_hosts([hostsd_tag])
if config['static_host_mapping']:
hc.add_hosts({hostsd_tag: config['static_host_mapping']})
hc.apply()
except vyos.hostsd_client.VyOSHostsdError as e:
raise ConfigError(str(e))
## Actually update the hostname -- vyos-hostsd doesn't do that
# No domain name -- the Debian way.
hostname_new = config['hostname']
# rsyslog runs into a race condition at boot time with systemd
# restart rsyslog only if the hostname changed.
hostname_old = cmd('hostnamectl --static')
call(f'hostnamectl set-hostname --static {hostname_new}')
# Restart services that use the hostname
if hostname_new != hostname_old:
call("systemctl restart rsyslog.service")
# If SNMP is running, restart it too
if process_named_running('snmpd'):
call('systemctl restart snmpd.service')
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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