#!/usr/bin/env python3 # # Copyright (C) 2018 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 . # # """ conf-mode script for 'system host-name' and 'system domain-name'. """ import os import re import sys import copy import glob import subprocess import argparse import jinja2 from vyos.config import Config from vyos import ConfigError parser = argparse.ArgumentParser() parser.add_argument("--dhclient", action="store_true", help="Started from dhclient-script") config_file_hosts = '/etc/hosts' config_file_resolv = '/etc/resolv.conf' config_tmpl_hosts = """ ### Autogenerated by host_name.py ### 127.0.0.1 localhost 127.0.1.1 {{ hostname }}{% if domain_name %}.{{ domain_name }}{% endif %} # The following lines are desirable for IPv6 capable hosts ::1 localhost ip6-localhost ip6-loopback fe00::0 ip6-localnet ff00::0 ip6-mcastprefix ff02::1 ip6-allnodes ff02::2 ip6-allrouters # static hostname mappings {%- if static_host_mapping['hostnames'] %} {% for hn in static_host_mapping['hostnames'] -%} {{static_host_mapping['hostnames'][hn]['ipaddr']}}\t{{static_host_mapping['hostnames'][hn]['alias']}}\t{{hn}} {% endfor -%} {%- endif %} ### modifications from other scripts should be added below """ config_tmpl_resolv = """ ### Autogenerated by host_name.py ### {% for ns in nameserver -%} nameserver {{ ns }} {% endfor -%} {%- if domain_name %} domain {{ domain_name }} {%- endif %} {%- if domain_search %} search {{ domain_search | join(" ") }} {%- endif %} """ default_config_data = { 'hostname': 'vyos', 'domain_name': '', 'domain_search': [], 'nameserver': [], 'no_dhcp_ns': False } # borrowed from: https://github.com/donjajo/py-world/blob/master/resolvconfReader.py, THX! def get_resolvers(file): resolv = {} try: with open(file, 'r') as resolvconf: lines = [line.split('#', 1)[0].rstrip() for line in resolvconf.readlines()] resolvers = [line.split()[1] for line in lines if 'nameserver' in line] domains = [line.split()[1] for line in lines if 'search' in line] resolv['resolvers'] = resolvers resolv['domains'] = domains return resolv except IOError: return [] def get_config(arguments): conf = Config() hosts = copy.deepcopy(default_config_data) if arguments.dhclient: conf.exists = conf.exists_effective conf.return_value = conf.return_effective_value conf.return_values = conf.return_effective_values if conf.exists("system host-name"): hosts['hostname'] = conf.return_value("system host-name") 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"): hosts['nameserver'] = conf.return_values("system name-server") if conf.exists("system disable-dhcp-nameservers"): hosts['no_dhcp_ns'] = conf.exists('system disable-dhcp-nameservers') # system static-host-mapping hosts['static_host_mapping'] = {'hostnames': {}} if conf.exists('system static-host-mapping host-name'): for hn in conf.list_nodes('system static-host-mapping host-name'): hosts['static_host_mapping']['hostnames'][hn] = { 'ipaddr': conf.return_value('system static-host-mapping host-name ' + hn + ' inet'), 'alias': '' } if conf.exists('system static-host-mapping host-name ' + hn + ' alias'): a = conf.return_values( 'system static-host-mapping host-name ' + hn + ' alias') hosts['static_host_mapping']['hostnames'][hn]['alias'] = " ".join(a) return hosts def verify(config): if config 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(config['hostname']): raise ConfigError('Invalid host name ' + config["hostname"]) # pattern $VAR(@) "^.{1,63}$" ; "invalid host-name length" length = len(config['hostname']) if length < 1 or length > 63: raise ConfigError( 'Invalid host-name length, must be less than 63 characters') # The search list is currently limited to six domains with a total of 256 characters. # https://linux.die.net/man/5/resolv.conf if len(config['domain_search']) > 6: raise ConfigError( 'The search list is currently limited to six domains') tmp = ' '.join(config['domain_search']) if len(tmp) > 256: raise ConfigError( 'The search list is currently limited to 256 characters') # static mappings alias hostname if config['static_host_mapping']['hostnames']: for hn in config['static_host_mapping']['hostnames']: if not config['static_host_mapping']['hostnames'][hn]['ipaddr']: raise ConfigError('IP address required for ' + hn) for hn_alias in config['static_host_mapping']['hostnames'][hn]['alias'].split(' '): if not hostname_regex.match(hn_alias) and len(hn_alias) != 0: raise ConfigError('Invalid hostname alias ' + hn_alias) return None def generate(config): if config is None: return None # If "system disable-dhcp-nameservers" is __configured__ all DNS resolvers # received via dhclient should not be added into the final 'resolv.conf'. # # We iterate over every resolver file and retrieve the received nameservers # for later adjustment of the system nameservers dhcp_ns = [] dhcp_sd = [] for file in glob.glob('/etc/resolv.conf.dhclient-new*'): for key, value in get_resolvers(file).items(): ns = [r for r in value if key == 'resolvers'] dhcp_ns.extend(ns) sd = [d for d in value if key == 'domains'] dhcp_sd.extend(sd) if not config['no_dhcp_ns']: config['nameserver'] += dhcp_ns config['domain_search'] += dhcp_sd # We have third party scripts altering /etc/hosts, too. # One example are the DHCP hostname update scripts thus we need to cache in # every modification first - so changing domain-name, domain-search or hostname # during runtime works old_hosts = "" with open(config_file_hosts, 'r') as f: # Skips text before the beginning of our marker. # NOTE: Marker __MUST__ match the one specified in config_tmpl_hosts for line in f: if line.strip() == '### modifications from other scripts should be added below': break for line in f: # This additional line.strip() filters empty lines if line.strip(): old_hosts += line # Add an additional newline old_hosts += '\n' tmpl = jinja2.Template(config_tmpl_hosts) config_text = tmpl.render(config) with open(config_file_hosts, 'w') as f: f.write(config_text) f.write(old_hosts) tmpl = jinja2.Template(config_tmpl_resolv) config_text = tmpl.render(config) with open(config_file_resolv, 'w') as f: f.write(config_text) return None def apply(config): if config is None: return None fqdn = config['hostname'] if config['domain_name']: fqdn += '.' + config['domain_name'] # rsyslog runs into a race condition at boot time with systemd # restart rsyslog only if the hostname changed. hn = subprocess.check_output(['hostnamectl', '--static']).decode().strip() os.system("hostnamectl set-hostname --static {0}".format(fqdn.rstrip('.'))) # Restart services that use the hostname if hn != fqdn: os.system("systemctl restart rsyslog.service") # If SNMP is running, restart it too if os.system("pgrep snmpd > /dev/null") == 0: os.system("systemctl restart snmpd.service") # restart pdns if it is used if os.system("/usr/bin/rec_control ping >/dev/null 2>&1") == 0: os.system("/etc/init.d/pdns-recursor restart >/dev/null") return None if __name__ == '__main__': args = parser.parse_args() try: c = get_config(args) verify(c) generate(c) apply(c) except ConfigError as e: print(e) sys.exit(1)