#!/usr/bin/env python3 import argparse import json import logging import logging.handlers import os import re import sys import warnings ## import dns.exception import dns.resolver import requests ## from lxml import etree try: # https://www.freedesktop.org/software/systemd/python-systemd/journal.html#journalhandler-class from systemd import journal _has_journald = True except ImportError: _has_journald = False logfile = '~/.cache/ddns.log' # Prep the log file. logfile = os.path.abspath(os.path.expanduser(logfile)) os.makedirs(os.path.dirname(logfile), exist_ok = True, mode = 0o0700) if not os.path.isfile(logfile): with open(logfile, 'w') as fh: fh.write('') os.chmod(logfile, 0o0600) # And set up logging. _cfg_args = {'handlers': [], 'level': logging.DEBUG} if _has_journald: # There were some weird changes somewhere along the line. try: # But it's *probably* this one. h = journal.JournalHandler() except AttributeError: h = journal.JournaldLogHandler() # Systemd includes times, so we don't need to. h.setFormatter(logging.Formatter(style = '{', fmt = ('{name}:{levelname}:{name}:{filename}:' '{funcName}:{lineno}: {message}'))) _cfg_args['handlers'].append(h) h = logging.handlers.RotatingFileHandler(logfile, encoding = 'utf8', # Disable rotating for now. # maxBytes = 50000000000, # backupCount = 30 ) h.setFormatter(logging.Formatter(style = '{', fmt = ('{asctime}:' '{levelname}:{name}:{filename}:' '{funcName}:{lineno}: {message}'))) _cfg_args['handlers'].append(h) logging.basicConfig(**_cfg_args) logger = logging.getLogger('DDNS') logger.info('Logging initialized.') is_tty = sys.stdin.isatty() if not is_tty: logger.debug('Not running in an interactive invocation; disabling printing warnings') else: logger.debug('Running in an interactive invocation; enabling printing warnings') class Updater(object): tree = None records = {} api_base = None session = None token = None my_ips = {4: None, 6: None} resolver = dns.resolver.Resolver(configure = False) resolver.nameservers = ['64.6.64.6', '64.6.65.6'] def __init__(self, cfg_path = '~/.config/ddns.xml', *args, **kwargs): self.xml = os.path.abspath(os.path.expanduser(cfg_path)) logger.debug('Updater initialized with config {0}'.format(self.xml)) self._getConf() self._getMyIP() self._getSession() def _getConf(self): try: with open(self.xml, 'rb') as fh: self.xml = etree.fromstring(fh.read()) except FileNotFoundError as e: logger.error('Configuration file does not exist; please create it') raise e self.tree = self.xml.getroottree() self.token = self.xml.attrib['token'] self.api_base = re.sub(r'/$', '', self.xml.attrib['base']) dom_xml = self.xml.findall('domain') num_doms = len(dom_xml) logger.debug('Found {0} domains in config'.format(num_doms)) for idx, d in enumerate(dom_xml): domain = d.attrib['name'] logger.debug('Iterating domain {0} ({1}/{2})'.format(domain, (idx + 1), num_doms)) if domain not in self.records.keys(): self.records[domain] = [] sub_xml = d.findall('sub') num_subs = len(sub_xml) logger.debug('Found {0} records for domain {1}'.format(num_subs, domain)) for idx2, s in enumerate(sub_xml): logger.debug('Adding record {0}.{1} to index ({2}/{3})'.format(s.text, domain, (idx2 + 1), num_subs)) self.records[domain].append(s.text) return() def _getDNS(self, record): records = {} for t in ('A', 'AAAA'): logger.debug('Resolving {0} ({1})'.format(record, t)) try: q = self.resolver.query(record, t) for a in q: if t not in records.keys(): records[t] = [] ip = a.to_text() logger.debug('Found IP {0} for record {1} ({2})'.format(ip, record, t)) records[t].append(ip) except dns.exception.Timeout as e: logger.error('Got a timeout when resolving {0} ({1}): {2}'.format(record, t, e)) continue except dns.resolver.NXDOMAIN as e: # This is a debug instead of an error because that record type may not exist. logger.debug('Record {0} ({1}) does not exist: {2}'.format(record, t, e)) continue except dns.resolver.YXDOMAIN as e: logger.error('Record {0} ({1}) is too long: {2}'.format(record, t, e)) continue except dns.resolver.NoAnswer as e: # This is a debug instead of an error because that record type may not exist. logger.debug('Record {0} ({1}) exists but has no content: {2}'.format(record, t, e)) continue except dns.resolver.NoNameservers as e: logger.error(('Could not failover to a non-broken resolver when resolving {0} ({1}): ' '{2}').format(record, t, e)) continue return(records) def _getMyIP(self): for v in self.my_ips.keys(): try: logger.debug('Getting the client\'s WAN address for IPv{0}'.format(v)) r = requests.get('https://ipv{0}.clientinfo.square-r00t.net/?raw=1'.format(v)) if not r.ok: logger.error('Got a non-OK response from WAN IPv{0} fetch.'.format(v)) raise RuntimeError('Could not get the IPv{0} address'.format(v)) ip = r.json()['ip'] logger.debug('Got WAN IP address {0} for IPv{1}'.format(ip, v)) self.my_ips[v] = ip except requests.exceptions.ConnectionError: logger.debug('Could not get WAN address for IPv{0}; likely not supported on this network'.format(v)) return() def _getSession(self): self.session = requests.Session() self.session.headers.update({'Authorization': 'Bearer {0}'.format(self.token)}) return() def update(self): for d in self.records.keys(): d_f = json.dumps({'domain': d}) doms_url = '{0}/domains'.format(self.api_base) logger.debug('Getting list of domains from {0} (filtered to {1})'.format(doms_url, d)) d_r = self.session.get(doms_url, headers = {'X-Filter': d_f}) if not d_r.ok: e = 'Could not get list of domains when attempting to check {0}; skipping'.format(d) if is_tty: warnings.warn(e) logger.warning(e) continue try: d_id = d_r.json()['data'][0]['id'] except (IndexError, KeyError): e = 'Could not find domain {0} in the returned domains list; skipping'.format(d) if is_tty: warnings.warn(e) logger.warning(e) continue for s in self.records[d]: fqdn = '{0}.{1}'.format(s, d) logger.debug('Processing {0}'.format(fqdn)) records = self._getDNS(fqdn) for v, t in ((4, 'A'), (6, 'AAAA')): ip = self.my_ips.get(v) rrset = records.get(t) if not ip: e = 'IPv{0} disabled; skipping'.format(v) warnings.warn(e) if is_tty: logger.warning(e) continue if rrset and ip in rrset: e = 'Skipping adding {0} for {1}; already exists in DNS'.format(ip, fqdn) logger.info(e) if is_tty: print(e) continue s_f = json.dumps({'name': s, 'type': t}) records_url = '{0}/domains/{1}/records'.format(self.api_base, d_id) logger.debug(('Getting list of records from {0} ' '(filtered to name {1} and type {2})').format(records_url, s, t)) s_r = self.session.get(records_url, headers = {'X-Filter': s_f}) if not s_r.ok: e = 'Could not get list of records when attempting to check {0} ({1}); skipping'.format(fqdn, t) if is_tty: warnings.warn(e) logger.warning(e) continue r_ids = set() # If r_exists is: # None, then the record exists but the current WAN IP is missing (all records replaced). # False, then the record does not exist (record will be added). # True, then the record exists and is current (nothing will be done). r_exists = None try: api_records = s_r.json().pop('data') for idx, r in enumerate(api_records): r_ids.add(r['id']) r_ip = r['target'] if r_ip == ip: r_exists = True except (IndexError, KeyError): e = ('Could not find record {0} ({1}) in the returned records list; ' 'creating new record').format(fqdn, t) if is_tty: print(e) logger.info(e) r_exists = False if r_exists: # Do nothing. e = 'Skipping adding {0} for {1}; already exists in API and is correct'.format(ip, fqdn) logger.info(e) if is_tty: print(e) continue elif r_exists is None: # Remove all records and then add (at the end). # We COULD do an update: # https://developers.linode.com/api/v4/domains-domain-id-records-record-id/#put # BUT then we break future updating since we don't know which record is the "right" one to # update. logger.debug('Record {0} ({1}) exists but does not contain {2}; replacing'.format(fqdn, t, ip)) for r_id in r_ids: del_url = '{0}/domains/{1}/records/{1}'.format(self.api_base, d_id, r_id) logger.debug(('Deleting record ID {0} for {1} ({2})').format(r_id, fqdn, t)) del_r = self.session.delete(records_url) if not del_r.ok: e = 'Could not delete record ID {0} for {1} ({2}); skipping'.format(r_id, fqdn, t) if is_tty: warnings.warn(e) logger.warning(e) continue else: # Create the record. logger.debug('Record {0} ({1}) does not exist; creating'.format(fqdn, ip)) record = {'name': s, 'type': t, 'target': ip, 'ttl_sec': 300} create_url = '{0}/domains/{1}/records'.format(self.api_base, d_id) create_r = self.session.post(create_url, json = record) if not create_r.ok: e = 'Could not create record {0} ({1}); skipping'.format(fqdn, t) if is_tty: warnings.warn(e) logger.warning(e) continue return() def parseArgs(): args = argparse.ArgumentParser(description = ('Automatically update Linode DNS via their API')) args.add_argument('-c', '--config', dest = 'cfg_path', default = '~/.config/ddns.xml', help = ('The path to the configuration file. Default: ~/.config/ddns.xml')) return(args) def main(): args = parseArgs().parse_args() u = Updater(**vars(args)) u.update() return(None) if __name__ == '__main__': main()