需要定义名为“受攻击的\u开关”的全局变量

Question

我正在使用GitHub的代码，通过泛光灯控制器中的反应流规则来缓解DDoS攻击。我无法运行该程序，因为没有定义全局变量attacked_switches，但我不知道如何执行该操作。有人能帮我吗

From GitHub

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def start():

    try:

        number_of_switches, number_of_hosts = topology_info()
        switch_dpids = list()
        hosts = dict()
        switch_dpids = switch_info(number_of_switches, switch_dpids)
        hosts = host_info(number_of_hosts, hosts)
        dpid = switch_byte(number_of_switches, switch_dpids)
        print 'dpid= ', dpid
        if dpid != 0:
            print'calling flow pusher'
            global attack
            attack = True
            attacked_switches.add(dpid)
            T2 = threading.Thread(target=Flowpusher, args=[dpid])
            T2.start()
        elif attack:
            T3 = threading.Thread(target=Flowremover, args=[dpid])
            T3.start()

    except Exception as e:
        print'Error occured:', e

Answer 1

您只需在变量名之前（变量的第一个asignment之前）键入global即可定义全局变量。因此：

global attacked_switches

参见示例here

编辑：查看github代码，将attacked_switches指定为全局变量对您没有帮助。您引用的代码有attacked_switches.add(dpid)行，但我找不到attacked_switches的定义位置