Python Network Programming

How to do it...

Let us sniff the packets using the sniff() function of Scapy and define a callback function, modify_packet_header(), which adds an extra header of certain packets.

Listing 8.3 gives the code for adding an extra header in HTTP packets, as follows:

#!/usr/bin/env python 
# Python Network Programming Cookbook, Second Edition -- Chapter - 8 
# This program is optimized for Python 2.7.12 and Python 3.5.2. 
# It may run on any other version with/without modifications. 
 
 
from scapy.all import * 
 
def modify_packet_header(pkt): 
    """ Parse the header and add an extra header""" 
    if pkt.haslayer(TCP) and pkt.getlayer(TCP).dport == 80 and pkt.haslayer(Raw): hdr = pkt[TCP].payload.__dict__ extra_item = {'Extra Header' : ' extra value'} hdr.update(extra_item) ...