CODEWITHSUNDEEP
pythonpcap
Boaz
Boaz

Reputation: 5084

creating a pcap file using python

I'm trying to create a very simple PCAP file (1 UDP message).
Tried using dpkt (pcap.Writer), no luck, and the documentation is scarce.
Can anyone post a working example?
(or any other alternative - I'm not bound to dpkt)

Upvotes: 3

Views: 17414

Answers (4)

Nagmat
Nagmat

Reputation: 382

You can try the code below :

#!/usr/bin/env python3
import sys
import struct
import os
import argparse

from scapy.all import sniff, sendp, hexdump, linehexdump, get_if_list, get_if_hwaddr
from scapy.all import Packet, IPOption
from scapy.all import ShortField, IntField, LongField, BitField, FieldListField, FieldLenField
from scapy.all import IP, TCP, UDP, Raw
from scapy.layers.inet import _IPOption_HDR
from scapy.all import raw
from scapy.all import bytes_hex
import hashlib
import pcapng.blocks as blocks
from pcapng import FileWriter


counter = 1

def get_if():
    ifs=get_if_list()
    iface=None
    for i in get_if_list():
        if "enp1s0f1" in i:
            iface=i
            break;
    if not iface:
        print("Cannot find eth0 interface")
        exit(1)
    return iface


def main():
    global counter
    ifaces = [i for i in os.listdir('/sys/class/net/') ]
    iface = get_if()
    print(("sniffing on %s" % iface))
    sys.stdout.flush()
    writer = FileWriter(args.outfile, shb)

    orig_packets = sniff(filter='tcp and port 5201',iface = iface)
    for packet in orig_packets:
        spb = shb.new_member(blocks.SimplePacket)
        spb.packet_data = bytes(packet)
        writer.write_block(spb)
        print("C=",counter)
        counter=counter+1

if __name__ == '__main__':
    parser = argparse.ArgumentParser()
    parser.add_argument("outfile", type=argparse.FileType("wb"))
    args = parser.parse_args()

    shb = blocks.SectionHeader(
    options={
        "shb_hardware": "artificial",
        "shb_os": "python",
        "shb_userappl": "python-pcapng",
    })
    idb = shb.new_member(
    blocks.InterfaceDescription,
    link_type=1,
    options={
        "if_description": "Hand-rolled",
        "if_os": "Python",
        "if_filter": [(0, b"tcp port 5201 and host 192.168.1.3")],
    },)

    main()

Upvotes: 0

synthesizerpatel
synthesizerpatel

Reputation: 28036

construct's cap (broken link) shows how to use construct for this. Construct also has a rudimentary ip stack (broken link) example. The nice thing about Construct is that it is symmetrical, i.e. you can put data into it, convert it to a set of Python objects and you can then dump out the objects to create the original data blob again.

Upvotes: 0

Havok
Havok

Reputation: 5882

You may use Scapy.

https://scapy.readthedocs.io/en/latest/installation.html

If using Python 3:

pip3 install scapy

Then in Python:

from scapy.all import wrpcap, Ether, IP, UDP
packet = Ether() / IP(dst="1.2.3.4") / UDP(dport=123)
wrpcap('foo.pcap', [packet])

Upvotes: 14

devesh
devesh

Reputation: 76

you need to write the packet into a libpcap format

Global Header + Packet Header + Packet Data + Packet Header + Packet Data this link should help you

http://www.codeproject.com/Tips/612847/Generate-a-quick-and-easy-custom-pcap-file-using-P

Upvotes: 2

Related Questions