code: def _find_chain_name(self, mac):
          
  
          ipt_cmd = ['iptables', '-t', 'filter', '-S']
          cmdo = dsl.execute(ipt_cmd, root_helper=self._root_helper,
                             log_output=False)
          for o in cmdo.split('\n'):
              if mac in o.lower():
                  chain = o.split()[1]
                  LOG.info('Find %(chain)s for %(mac)s.',
                           {'chain': chain, 'mac': mac})
                  return chain
docs: Find a rule associated with a given mac.