get packet size in scapy / python

python size packet scapy
Ricky Robinson picture Ricky Robinson · May 11, 2012 · Viewed 20.7k times · Source

In Scapy (or even just Python, for that sake), how do I get the size in bytes of a given packet? I'm tempted to use the function len but I'm not sure what exactly it returns in the case of packets.

>>> len(IP(dst="www.google.com"))
20

>>> len(IP(dst="www.google.com")/TCP(dport=80))
40

Answer

MattH picture MattH · May 11, 2012 
>>> len(IP(dst="www.google.com"))
20

There are 20 bytes in a minimal IP header.

>>> len(IP(dst="www.google.com")/TCP(dport=80))
40

There are another 20 bytes in a minimal TCP header (20+20==40).

So it seems that len is returning the packet length.

Related questions

Getting file size in Python?

Is there a built-in function for getting the size of a file object in bytes? I see some people do something like this: def getSize(fileobject): fileobject.seek(0,2) # move the cursor to the end of the file size = fileobject.tell() …

Read More
How to change legend size with matplotlib.pyplot

Simple question here: I'm trying to get the size of my legend using matplotlib.pyplot to be smaller (i.e., the text to be smaller). The code I'm using goes something like this: plot.figure() plot.scatter(k, sum_cf, …

Read More
Image size (Python, OpenCV)

I would like to get the Image size in python,as I do it with c++. int w = src->width; printf("%d", 'w');

Read More