Pyile Protocol Documentation:

Introduction:

This document describes the network protocol used by the Pyile application over TCP/IP on port 4702. The protocol is used for communication and authentication between peers.

Protocol Overview

The Pyile protocol is used for peer-to-peer communication and authentication. This protocol allows for a single central authenticator that established the network and is the source of all authentication within the given network. With this in mind, the authenticating peer has a unique role. It is still considered a peer which means that they still have full communication functionalities. The Pyile protocol supports another type of peer which is a non-authenticating peer or just peer. This type of peer only can be authenticated and send messages.

Sockets:

• Port 4702: Used as the main connection between peer and authenticating peer.
• Dynamic and private port: Randomly generated port that is within the private use range. Used for communication between all peers.
• Temporary Socket: Used to send messages and broadcast but is then closed immediately after.

Protocol Flow

• Authenticating peer is established listening on port 4702 for potential peers
• Authenticating peer, then generates a random port and begins to listen to already established peers. (Should only be themselves)
• A Joining peer then requests to be authenticated by the initial peer.
• The initial peer then checks if the peer is already banned and then checks the password.
• If the password is correct, then the peer is added and then given the list of peers that can be communicated with.
• A heartbeat is then established between both peers.
• The joining peer can now communicate in the network through broadcasting or individual messaging.

Special Flows

Heartbeat

• When a peer is authenticated, A heartbeat is established between the authenticating peer and peer.
• The peer is in a constant state of listening, waiting to send a response to the authenticating peer.
• If a timeout is reached on either sides, the peer will be removed from the list of established peers and must reauthenticate.

Exit

• Any time an exit is called by a peer, the instance variable disconnected will be set to True. All sockets will be closed and any loose threads will be joined.

Figure 1

Message Types

• Banned status - First message sent to peer from authenticating peer. if banned, connection with joining peer is dropped
• Authenticated - Second message sent from authenticating peer. If authenticated, a heartbeat is established
• Heartbeat - Sent throughout the life of the connection that ensures both peers are still alive.
• Set Distributions - When the Authenticating peer has made changes to the peer list, it redistributes to all the peers in the network.
• Communication - Simple messaging between peers

Error Handling

The protocol has custom exceptions to further the detail of errors:

• AuthenticationException
• StatusException
• SendException
• RecvException

Security

The protocol implements an authentication process equipped with a password check and banned status. At this time, there is no encryption.

Code Example

Install

pip install pyile_protocol

Authenticating Peer

import threading
from pyile_protocol.lib.peers.AuthPeer import AuthPeer

auth_peer = AuthPeer(address=("192.168.1.66", 4702), password_attempts=1, password="password")

auth_thread = threading.Thread(target=auth_peer.authenticate_peers)
peer_thread = threading.Thread(target=auth_peer.connect)
auth_thread.start()
peer_thread.start()

while not auth_peer.disconnected:
    data = input("~: ")
    if data == "exit":
        auth_peer.leave()
    elif data == "peers":
        print(auth_peer.peers)
    else:
        auth_peer.broadcast(data)

Peer

import threading
from pyile_protocol.lib.peers.JoinPeer import JoinPeer
peer = JoinPeer(address=("192.168.1.65", 4702))
peer.get_authenticated(("192.168.1.66", 4702), "password")


connect_thread = threading.Thread(target=peer.connect)
connect_thread.start()


while not peer.disconnected:
    data = input("~: ")
    if data == "exit":
        peer.leave()

    elif data == "peers":
        print(peer.peers)
    else:
        peer.broadcast(data)