ping.py 文件源码

def ping_host(self, ip):
        """method to send ICMP/ARP requests and receive response
        from the host with @ip address.
        Returns a tuple (ip/host name, ONLINE/OFFLINE, response time)"""

        # form an ICMP or ARP packet
        packet = self.__gen_packet(ip)

        try:
            # send and wait for response
            answers, unanswers = self.__send_recv(packet)
        except PermissionError:
            raise PermissionException

        if self.__resolve_names:
            # resolve host name by ip if resolve_names
            # flag was set
            try:
                host = gethostbyaddr(ip)[HOST_NAME_INDEX]
            except herror:
                host = ip
        else:
            # otherwise show ip
            host = ip

        if answers:
            answer = answers[FIRST_INDEX]
            # get the request object
            req = answer[REQUEST_INDEX]
            # get the response object
            resp = answer[RESPONSE_INDEX]
            # calculate response time and round it
            delta = resp.time - req.sent_time
            return host, ONLINE, delta
        else:
            # return unansered results
            unanswer = unanswers[FIRST_INDEX]
            resp = unanswer[RESPONSE_INDEX]
            return host, OFFLINE, None