用python scapy库分析pcap数据包错误TypeError、AttributeError

Question

写了个python程序解析流量数据包，用的是scapy库。读取流量较少的pcap包文件时可以顺利运行，读取大点的pcap包就会报错。
错误信息如下：

        Traceback (most recent call last):
    File "C:\Users\ASUS\AppData\Local\Programs\Python\Python36\lib\site-packages\scapy\packet.py", line 235, in __getattr__
        fld, v = self.getfield_and_val(attr)
            TypeError: 'NoneType' object is not iterable

    During handling of the above exception, another exception occurred:

    Traceback (most recent call last):
    File "C:\Users\ASUS\AppData\Local\Programs\Python\Python36\lib\site-packages\scapy\packet.py", line 235, in __getattr__
        fld, v = self.getfield_and_val(attr)
    TypeError: 'NoneType' object is not iterable

    During handling of the above exception, another exception occurred:

    Traceback (most recent call last):
    File "D:\Paper\sta\pcap\特征提取.py", line 22, in <module>
        bufLen.append(data.len)
    File "C:\Users\ASUS\AppData\Local\Programs\Python\Python36\lib\site-packages\scapy\packet.py", line 237, in __getattr__
        return self.payload.__getattr__(attr)
    File "C:\Users\ASUS\AppData\Local\Programs\Python\Python36\lib\site-packages\scapy\packet.py", line 237, in __getattr__
        return self.payload.__getattr__(attr)
    File "C:\Users\ASUS\AppData\Local\Programs\Python\Python36\lib\site-packages\scapy\packet.py", line 235, in __getattr__
        fld, v = self.getfield_and_val(attr)
    File "C:\Users\ASUS\AppData\Local\Programs\Python\Python36\lib\site-packages\scapy\packet.py", line 1291, in getfield_and_val
        raise AttributeError(attr)
    AttributeError: len

源代码部分：

    from scapy.all import *
    from scapy.utils import PcapReader

    rd = PcapReader('./a.pcap')                               
    while True:
        data = rd.read_packet()
            if data is None:
                break
            else:
                '''
                    分析处理过程

                    '''
    rd.close()

源代码处理过程应该没问题，毕竟可以运行处理小数据包，但数据量一大就会报错。
而且有时候不稳定，简单的同样的代码有时可以运行成功，有时也会报上面的错，我想是不是系统的问题，我用的是在windows10，内存16G应该足够大，为什么会报错呢，求大神解答！

Answer 1

提取的pcap包里有其他协议类型的数据包，像ARP包就没有len属性，会报错。把打开的包里的协议类型过滤一下。