.bin/google-wifi-he-dyn-dns

   1 #!/usr/bin/env python3
   2
   3 """Update HS DNS settings behind Google WiFi systems."""
   4
   5 import argparse
   6 import json
   7 import urllib.request
   8 import urllib.parse
   9 import sys
  10
  11 import dns.resolver
  12
  13
  14 WIFI_STATUS_URI = 'http://192.168.86.1/api/v1/status'
  15
  16
  17 def get_wan_ip():
  18     with urllib.request.urlopen(WIFI_STATUS_URI) as req:
  19         data = req.read()
  20     status = json.loads(data)
  21     return status['wan']['localIpAddress']
  22
  23
  24 def update_ip(hostname, password, ip=None):
  25     """Update HE DNS with new settings."""
  26     params = {
  27         'hostname': hostname,
  28         'password': password,
  29     }
  30     if ip:
  31         params['myip'] = ip
  32     body = urllib.parse.urlencode(params).encode()
  33
  34     url = 'https://dyn.dns.he.net/nic/update'
  35     req = urllib.request.Request(url, body)
  36
  37     with urllib.request.urlopen(req) as response:
  38         return response.read()
  39
  40
  41 def get_parser():
  42     """Get CLI parser."""
  43     parser = argparse.ArgumentParser(description=__doc__)
  44     parser.add_argument('--hostname', required=True)
  45     parser.add_argument('-p', '--password', '--key', required=True)
  46     parser.add_argument('-a', '--address', '--ip')
  47     parser.add_argument('-q', '--quiet', action='store_true')
  48     return parser
  49
  50
  51 def main(argv):
  52     """The main entry point for scripts."""
  53     parser = get_parser()
  54     opts = parser.parse_args(argv)
  55
  56     if opts.quiet:
  57         p = lambda *args: None
  58     else:
  59         p = print
  60
  61     curr_ip = get_wan_ip()
  62     p('Current IP', curr_ip)
  63
  64     p('Looking up', opts.hostname, '...')
  65     answers = dns.resolver.resolve(opts.hostname, 'A')
  66     for msg in answers:
  67         p('Current DNS', msg.to_text())
  68         if curr_ip != msg.to_text():
  69             p('Updating IP')
  70             resp = update_ip(opts.hostname, opts.password, opts.address)
  71             p(resp)
  72         else:
  73             p('Up-to-date!')
  74         break
  75
  76
  77 if __name__ == '__main__':
  78     sys.exit(main(sys.argv[1:]))