如果字段名称是字符串变量，如何从数据包层获取字段值？

Question

我有和作为变量。如何获取字段值？layerfield#packet is just a sniff() packetlayer = "IP"field = "src"# I need something likefieldValue = packet[layer].field# orfieldValue = packet[layer].getfieldval(field)print("Layer: ", layer, " Field: ", field, " Value: ", fieldValue)#Output- Layer: IP Field: src Value: 192.168.1.1

Answer 1

假设我们正在嗅探带有scapy的数据包，并希望查看其中的值。其中大部分是使用 scapy 文档来查找每个层具有的属性的问题。您也可以在python / scapy解释器中执行此操作，以查看它具有哪些属性和方法。例如：dir(packet)

>>> dir(packet)

...

 'show',

 'show2',

 'show_indent',

 'show_summary',

 'sniffed_on',

 'sprintf',

 'src',

...

要从数据包中动态获取源属性，我们需要使用 getattr 函数，该函数可以从对象获取方法和属性。

# Required if you are not using the scapy interpreter

from scapy.all import sniff, IP

layer = "IP"

field = "src"

# Sniff 4 packets, filtering for packets with an IP layer

packet_list = sniff(filter="ip", count=4)

# Choose first packet arbitrarily

packet0 = packet_list[0]

# We can get the attribute reflexively because python allows it

field_value = getattr(packet0[layer], field)

# Print this information

print("Layer: ", layer, " Field: ", field, " Value: ", field_value)

---

> Layer:  IP  Field:  src  Value:  192.168.1.246