The pcap format, abbreviated from packet capture, is a common file format for saving network data. More details on the pcap format can be found at http://wiki.wireshark.org/Development/LibpcapFileFormat.
If you want to save your captured network packets to a file and later re-use them for further processing, this recipe can be a working example for you.
In this recipe, we use the Scapy library to sniff packets and write to a file. All utility functions and definitions of Scapy can be imported using the wild card import, as shown in the following command:
from scapy.all import *
This is only for demonstration purposes and not recommended for production code.
The sniff() function of Scapy takes the name of a callback function. Let's write a callback function that will write the packets onto a file.
Listing 9.2 gives the code for saving packets in the pcap format using the pcap dumper, as follows:
#!/usr/bin/env python # Python...