text: #!/usr/bin/env python3
  
  """ip filter plugin
  
  
  Copyright 2020 mnemonic AS <opensource@mnemonic.no>
  
  Permission to use, copy, modify, and/or distribute this software for any
  purpose with or without fee is hereby granted, provided that the above
  copyright notice and this permission notice appear in all copies.
  
  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
  REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
  INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
  LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
  OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  PERFORMANCE OF THIS SOFTWARE.
  
  echo the first line and return exit status based on IP type:
  
  Filter out all lines if parsed as IP address and IP is
  
  - Multicast (RFC 3171, RFC 2373)
  - Private (RC 1918, RFC 4193)
  - Unspecified (RFC 5735, RFC 2373)
  - Reserved (IETF)
  - Loopback (RF C3330, RFC 2372)
  - Link local (RF3927)
  
  """
  
  
  import ipaddress
  import sys
  import traceback
  from logging import debug, error
  
  from act.workers.libs import worker
  
  
  def process() -> None:
      """Read ip addresses from stdin"""
  
      output_rows = 0
  
      for line in sys.stdin:
          line = line.strip()
  
          if not line:
              continue
  
          try:
              ip = ipaddress.ip_address(line)
          except ValueError:
              # No IP Address
              print(line)
              output_rows += 1
              continue
  
          if ip.is_multicast:
              #  reserved for multicast use. See RFC 3171 (for IPv4) or RFC 2373 (for IPv6).
              continue
  
          if ip.is_private:
              # private networks. See RFC 1918 (for IPv4) or RFC 4193 (for IPv6).
              continue
  
          if ip.is_unspecified:
              # unspecified. See RFC 5735 (for IPv4) or RFC 2373 (for IPv6).
              continue
  
          if ip.is_reserved:
              # IETF reserved.
              continue
  
          if ip.is_loopback:
              # loopback address. See RFC 3330 (for IPv4) or RFC 2373 (for IPv6).
              continue
  
          if ip.is_link_local:
              # link-local usage. See RFC 3927.
              continue
  
          print(line)
          output_rows += 1
  
      if not output_rows:
          debug("All rows are filtered out")
  
  
  def main() -> None:
      """Main function"""
      args = worker.handle_args(worker.parseargs("IP Filter"))
      worker.init_act(args)
      process()
  
  
  def main_log_error() -> None:
      "Main function wrapper. Log all exceptions to error"
      try:
          main()
      except Exception:
          error("Unhandled exception: {}".format(traceback.format_exc()))
          raise
  
  
  if __name__ == '__main__':
      main_log_error()
  