def ip2host(self, ip): """Get reverse host name from an IP address, or None""" if not ip.startswith(self.ip_prefix) or not ip_or_none(ip): return None nums = ip[len(self.ip_prefix):].split('.') nums.reverse() return '.'.join(nums)
def host2ip(self, host): """Get IP address for the given reversed host name Return None if the result is not a valid IP address """ nums = host.split('.') nums.reverse() return ip_or_none(self.ip_prefix + '.'.join(nums))