code: def enqueue_event(self, event):
          
  
          LOG.debug('Enqueue iptable event %s.', event)
          if event.get('status') == 'up':
              for rule in self.rule_info:
                  if (rule.mac == event.get('mac').lower() and
                          rule.port == event.get('port')):
                      # Entry already exist in the list.
                      if rule.ip != event.get('ip'):
                          LOG.debug('enqueue_event: Only updating IP from %s'
                                    ' to %s.' % (rule.ip, event.get('ip')))
                          # Only update the IP address if it is different.
                          rule.ip = event.get('ip')
                          return
  
          self._iptq.put(event)
docs: Enqueue the given event.
  
          The event contains host data (ip, mac, port) which will be used to
          update the spoofing rule for the host in the iptables.