From e5df80a3f54da23858c382a8e491ff9901317e1e Mon Sep 17 00:00:00 2001 From: Daniil Baturin Date: Tue, 20 Aug 2019 18:53:35 +0200 Subject: T1598: initial implementation of the hosts keeper daemon. --- src/services/vyos-hostsd | 254 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 254 insertions(+) create mode 100755 src/services/vyos-hostsd (limited to 'src/services') diff --git a/src/services/vyos-hostsd b/src/services/vyos-hostsd new file mode 100755 index 000000000..972c2e3dc --- /dev/null +++ b/src/services/vyos-hostsd @@ -0,0 +1,254 @@ +#!/usr/bin/env python3 +# +# Copyright (C) 2019 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 . +# +# + +import os +import sys +import time +import json +import traceback + +import zmq + +import jinja2 + +debug = True + +DATA_DIR = "/var/lib/vyos/" +STATE_FILE = os.path.join(DATA_DIR, "hostsd.state") + +SOCKET_PATH = "ipc:///run/vyos-hostsd.sock" + +RESOLV_CONF_FILE = '/etc/resolv.conf' +HOSTS_FILE = '/etc/hosts' + +hosts_tmpl_source = """ +### Autogenerated by VyOS ### +127.0.0.1 localhost +127.0.1.1 {{ host_name }}{% 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 + + +{%- if hosts %} +{% for h in hosts -%} +{{hosts[h]['address']}}\t{{h}}\t{% for a in hosts[h]['aliases'] %} {{a}} {% endfor %} +{% endfor %} +{%- endif %} +""" + +hosts_tmpl = jinja2.Template(hosts_tmpl_source) + +resolv_tmpl_source = """ +### Autogenerated by VyOS ### +{% for ns in name_servers -%} +nameserver {{ns}} +{% endfor -%} + +{%- if domain_name %} +domain {{ domain_name }} +{%- endif %} + +{%- if search_domains %} +search {{ search_domains | join(" ") }} +{%- endif %} + +""" + +resolv_tmpl = jinja2.Template(resolv_tmpl_source) + +# The state data includes a list of name servers +# and a list of hosts entries. +# +# Name servers have the following structure: +# {"server": {"tag": }} +# +# Hosts entries are similar: +# {"host": {"tag": , "address": }} +# +# The tag is either "static" or "dhcp-" +# It's used to distinguish entries created +# by different scripts so that they can be removed +# and re-created without having to track what needs +# to be changed +STATE = { + "name_servers": {}, + "hosts": {}, + "host_name": "vyos", + "domain_name": "", + "search_domains": []} + + +def make_resolv_conf(data): + resolv_conf = resolv_tmpl.render(data) + print("Writing /etc/resolv.conf") + with open(RESOLV_CONF_FILE, 'w') as f: + f.write(resolv_conf) + +def make_hosts_file(state): + print("Writing /etc/hosts") + hosts = hosts_tmpl.render(state) + with open(HOSTS_FILE, 'w') as f: + f.write(hosts) + +def add_hosts(data, entries, tag): + hosts = data['hosts'] + + if not entries: + return + + for e in entries: + host = e['host'] + hosts[host] = {} + hosts[host]['tag'] = tag + hosts[host]['address'] = e['address'] + hosts[host]['aliases'] = e['aliases'] + +def delete_hosts(data, tag): + hosts = data['hosts'] + keys_for_deletion = [] + + # You can't delete items from a dict while iterating over it, + # so we build a list of doomed items first + for h in hosts: + if hosts[h]['tag'] == tag: + keys_for_deletion.append(h) + + for k in keys_for_deletion: + del hosts[k] + +def add_name_servers(data, entries, tag): + name_servers = data['name_servers'] + + if not entries: + return + + for e in entries: + name_servers[e] = {} + name_servers[e]['tag'] = tag + +def delete_name_servers(data, tag): + name_servers = data['name_servers'] + keys_for_deletion = [] + + for ns in name_servers: + if name_servers[ns]['tag'] == tag: + keys_for_deletion.append(ns) + + for k in keys_for_deletion: + del name_servers[k] + +def set_host_name(state, data): + if data['host_name']: + state['host_name'] = data['host_name'] + if data['domain_name']: + state['domain_name'] = data['domain_name'] + if data['search_domains']: + state['search_domains'] = data['search_domains'] + +def get_option(msg, key): + if key in msg: + return msg[key] + else: + raise ValueError("Missing required option \"{0}\"".format(key)) + +def handle_message(msg_json): + msg = json.loads(msg_json) + + op = get_option(msg, 'op') + _type = get_option(msg, 'type') + + if op == 'delete': + tag = get_option(msg, 'tag') + + if _type == 'name_servers': + delete_name_servers(STATE, tag) + elif _type == 'hosts': + delete_hosts(STATE, tag) + else: + raise ValueError("Unknown message type {0}".format(_type)) + elif op == 'add': + tag = get_option(msg, 'tag') + entries = get_option(msg, 'data') + if _type == 'name_servers': + add_name_servers(STATE, entries, tag) + elif _type == 'hosts': + add_hosts(STATE, entries, tag) + else: + raise ValueError("Unknown message type {0}".format(_type)) + elif op == 'set': + # Host name/domain name/search domain are set without a tag, + # there can be only one anyway + data = get_option(msg, 'data') + if _type == 'host_name': + set_host_name(STATE, data) + else: + raise ValueError("Unknown message type {0}".format(_type)) + else: + raise ValueError("Unknown operation {0}".format(op)) + + make_resolv_conf(STATE) + make_hosts_file(STATE) + + print("Saving state to {0}".format(STATE_FILE)) + with open(STATE_FILE, 'w') as f: + json.dump(STATE, f) + + +if __name__ == '__main__': + # Create a directory for state checkpoints + os.makedirs(DATA_DIR, exist_ok=True) + if os.path.exists(STATE_FILE): + with open(STATE_FILE, 'r') as f: + try: + data = json.load(f) + STATE = data + except: + print(traceback.format_exc()) + print("Failed to load the state file, using default") + + context = zmq.Context() + socket = context.socket(zmq.REP) + socket.bind(SOCKET_PATH) + + while True: + # Wait for next request from client + message = socket.recv().decode() + print("Received a configuration change request") + if debug: + print("Request data: {0}".format(message)) + + resp = {} + + try: + handle_message(message) + except ValueError as e: + resp['error'] = str(e) + except: + print(traceback.format_exc()) + resp['error'] = "Internal error" + + if debug: + print("Sent response: {0}".format(resp)) + + # Send reply back to client + socket.send(json.dumps(resp).encode()) -- cgit v1.2.3