dyngo

   1 #!/usr/bin/env python3
   2 import ipaddress, subprocess, sys, getopt,dbm
   3 from configparser import ConfigParser
   4 import urllib.request,urllib.parse
   5 class DyndnsNetwork(object):
   6     """
   7     This class represents dynamic DNS server and network.
   8     It has attributes hostname network server user and password
   9     """
  10     def __init__(self,config_section):
  11         self.hostname = config_section['hostname']
  12         self.network = ipaddress.ip_network(config_section['network'])
  13         self.server = config_section['server']
  14         if user in config_section:
  15             self.user=config_section["user"]
  16             self.password=config_section["password"]
  17
  18
  19     def contains(self,address):
  20         if self.network.prefixlen==0 and address.is_private:
  21             return False
  22         if self.network.version != address.version:
  23             return False
  24         return address in self.network
  25     def nsupdate(self, address):
  26         """
  27         Sends a get query to specified server.
  28         Raises HTTPError if something goes wrong
  29         """
  30         #construct opener
  31         if hasattr(self,user):
  32             password_mgr =urllib.request.HTTPPasswordMgrWithDefaultRealm()
  33             password_mgr.add_password(None,self.server,self.user,self.password)
  34             handler=urllib.request.HTTPBasicAuthHandler(password_mgr)
  35             opener = urllib.request.build_opener(handler)
  36         else:
  37             opener = urllib.request.build_opener()
  38         with opener.open('%s?%s'%(self.server,
  39                      urllib.parse.urlencode({'hostname':self.hostname,
  40                      'myip':str(address)}))) as req:
  41                req.read().decode("utf-8")
  42
  43
  44
  45 def get_current_addresses():
  46     result=[]
  47     for line in subprocess.run(['ip','-o','addr','show'],check=True,stdout=subprocess.PIPE).stdout.decode('utf-8').split("\n"):
  48         if not len(line):
  49             continue
  50         (no,iface,family,addr,rest)=line.split(maxsplit=4)
  51         address=ipaddress.ip_address(addr.split('/')[0])
  52         if address.is_loopback or address.is_link_local:
  53             continue
  54         result.append(address)
  55     return result
  56 def check_for_update():
  57     addrlist=get_current_addresses()
  58     for name,net in networks.items():
  59         found=False
  60         for a in addrlist:
  61             if net.contains(a):
  62                 found =True
  63                 if name in database:
  64                     old_addr=ipaddress.ip_address(database[name].decode("utf-8"))
  65                     if old_addr==a:
  66                         # Nothing changed go, to next net
  67                         break
  68                 # address changed
  69                 try:
  70                      net.nsupdate(a)
  71                      database[name]=str(a)
  72                 except urllib.error.HTTPError as e:
  73                     pass
  74                 break
  75         if not found:
  76             del data[name]
  77
  78
  79
  80
  81 config=ConfigParser()
  82 config['dyngo']={'interval':'60','database':'/var/lib/dyngo/dyngo.db','ca':'/etc/ssl/certs'}
  83 options=dict(getopt.getopt(sys.argv,"f:")[0])
  84 if not '-f' in options:
  85     options["-f"]="/etc/dyngo.conf"
  86 if len(config.read(options["-f"]))!=1:
  87     print("Cannot read config %s"%options["-f"],file=sys.stderr)
  88     sys.exit(1)
  89
  90 conf=config['dyngo']
  91 interval=int(conf['interval'])
  92 database=dbm.open(conf['database'],"c")
  93 https_params={}
  94 if 'ca' in conf and len(conf['ca']):
  95     path=conf['ca']
  96     if os.path.isdir(path):
  97         https_params['capath']=path
  98     else:
  99         http_params['cafile']=path
 100 # Convert all other config sections to DyndnsNetwork objects
 101 networks={}
 102 for sect in config.sections():
 103     if sect == 'dyngo' or sect == 'DEFAULT':
 104         continue
 105     networks[sect]=DyndnsNetwork(config[sect])
 106 # Remove stale items from persistent database, which are no more
 107 # mentioned in the config file
 108 for i in set([x.decode("utf-8") for x in database.keys()])-set(network.keys()):
 109     del database[i]
 110
 111
 112 while True:
 113     check_for_update()
 114     time.sleep(interval)
 115