Problem Statement
Two applications (written in python) - one reads a file and sends it over the network to the other application, which stores the file into its CWD. How would you do it (without using a framework that already does this)? L4 protocol of choice would be UDP, the reliability part is your duty
Solution
Sender side is implemented as UDP clients via gevent.sockets, revceiver side is implemented using gevent.server.DatagramServer. I created 4 packet types on the top of UDP for TCP like features. This is to avoid data corruption of files due to problems relating to UDP. Essentially pygftlib introduces sequencing and acknowledgement mechanism to ensure reliability.
sudo -H python3 install setup.py
The documentation regarding what this is and how it is implemented can be found here
$ pygftlib receive
__ _ _ _ _
_ __ _ _ __ _ / _| |_| (_) |__
| '_ \| | | |/ _` | |_| __| | | '_ \
| |_) | |_| | (_| | _| |_| | | |_) |
| .__/ \__, |\__, |_| \__|_|_|_.__/
|_| |___/ |___/
Version: 0.1
Module: Receiver Module. Please use compatible client to connect with this!
License: MIT
Credits: Made by Abhinav Saxena <xandfury@gmail.com>.
Special thanks to Daniel Haslinger and Team Honeynet for letting me do this!
Starting Receiver/Server on 127.0.0.1:12345
[INFO:2018-04-08 23:15:08,719]:root: Starting Receiver/Server on 127.0.0.1:12345
[INFO:2018-04-08 23:15:37,463]:pygftlib.protocol: New client has connected. Connection from 127.0.0.1:56270
[INFO:2018-04-08 23:15:37,464]:pygftlib.protocol: Creating new file with name: data.txt for client ('127.0.0.1', 56270)
[INFO:2018-04-08 23:15:38,475]:pygftlib.protocol: File Transfer Complete! Wrote 2018-04-08 23:15:37 - data-txt to disk
[INFO:2018-04-08 23:15:39,476]:pygftlib.protocol: Removing client ('127.0.0.1', 56270) context. Either transfer has completed or client has been inactive for over 40 seconds
[INFO:2018-04-08 23:15:39,477]:pygftlib.protocol: New client has connected. Connection from 127.0.0.1:56270
[WARNING:2018-04-08 23:15:39,479]:pygftlib.protocol: Invalid/Malformed INITRQ packet received from client ('127.0.0.1', 56270)