code.delx.au - monosys/blob - scripts/dyndns

   1 #!/usr/bin/python2
   2
   3 from datetime import datetime
   4 import os
   5 import subprocess
   6 import sys
   7 import re
   8
   9
  10 def increment_serial(line):
  11     current_serial = re.search(R"\b\d\d*\b", line).group(0)
  12
  13     current = int(current_serial)
  14     current_num = current % 100
  15     current_date = (current - current_num) / 100
  16     new_date = int(datetime.now().strftime("%Y%m%d"))
  17     if current_date == new_date:
  18         next_num = current_num + 1
  19     else:
  20         next_num = 0
  21
  22     if next_num >= 100:
  23         raise ValueError("Too many serial changes today!")
  24     new_serial = str(new_date) + str(next_num).zfill(2)
  25     line = line.replace(current_serial, new_serial)
  26
  27     return line
  28
  29 def replace_ip(line):
  30     source_ip, source_port, dest_ip, dest_port = os.environ["SSH_CONNECTION"].split()
  31     line = re.sub(R"\b\d\d?\d?\.\d\d?\d?\.\d\d?\d?\.\d\d?\d?\b", source_ip, line)
  32     return line
  33
  34
  35 def main(live, zonefile, dnslabel):
  36     f = open(zonefile)
  37     out = []
  38     for line in f:
  39         if line.find("Serial") >= 0:
  40             out.append(increment_serial(line))
  41         elif line.find("DYNDNS") >= 0 and line.find("bnet") >= 0:
  42             out.append(replace_ip(line))
  43         else:
  44             out.append(line)
  45
  46     f.close()
  47
  48     if live:
  49         outf = open(zonefile, "w")
  50         outf.writelines(out)
  51         outf.close()
  52         subprocess.check_call(["sudo", "/etc/init.d/bind9", "reload"])
  53     else:
  54         sys.stdout.writelines(out)
  55
  56
  57 if __name__ == "__main__":
  58     live = False
  59     try:
  60         i = 1
  61         if sys.argv[1] == "live":
  62             live = True
  63             i = 2
  64         zonefile = sys.argv[i]
  65         dnslabel = sys.argv[i+1]
  66     except:
  67         print >>sys.stderr, "Usage: %s [go] zonefile dnslabel" % sys.argv[0]
  68         sys.exit(1)
  69
  70     main(live, zonefile, dnslabel)
  71
  72