使用Scapy获取TCP标志 [英] Get TCP Flags with Scapy

问题描述

我正在解析一个PCAP文件，我需要提取TCP标志(SYN，ACK，PSH，URG等). 我正在使用packet['TCP'].flags值一次获取所有标志.

I'm parsing a PCAP file and I need to extract TCP flags (SYN, ACK, PSH, URG, ...). I'm using the packet['TCP'].flags value to obtain all the flags at once.

pkts = PcapReader(infile)
for p in pkts:
        F = bin(p['TCP'].flags)
        print F, bin(F), p.summary()
        # manual flags extraction from F

有没有一种方法可以获取单个TCP标志，而无需手动从packet['TCP'].flags值中提取它?

Is there a way to obtain a single TCP flag without manually extract it from packet['TCP'].flags value?

推荐答案

通常，处理FLAGS的常用方法是使用位图和按位运算符.如果您的Packet类没有用于测试标志的特定方法，那么IMHO最好的方法是:

Normally, the usual way to handle FLAGS is with a bitmap and bitwise operators. If your Packet class doesn't have specific method to test for flags, the best thing you can do IMHO is to:

FIN = 0x01
SYN = 0x02
RST = 0x04
PSH = 0x08
ACK = 0x10
URG = 0x20
ECE = 0x40
CWR = 0x80

并像这样测试它们:

F = p['TCP'].flags    # this should give you an integer
if F & FIN:
    # FIN flag activated
if F & SYN:
    # SYN flag activated
# rest of the flags here

可悲的是，python没有switch语句来使它更加优雅，但实际上并没有多大作用.

Sadly, python doesn't have a switch statement to make this more elegant but it doesn't really matter much.

希望这会有所帮助！

这篇关于使用Scapy获取TCP标志的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！