Rust SwapBytes - P2P File Swapping Application

A secure peer-to-peer file swapping application built with Rust and libp2p that enables users to discover peers, chat in a global room, establish direct messaging connections, and securely exchange files with end-to-end encryption.

Table of Contents

• Features
• Requirements
• Installation
• Command Line Parameters
• Running the Application
  • Starting the Rendezvous Server
  • Starting Client Applications
  • Multiple Computer Setup
• Application Usage
  • Global Chat Commands
  • Direct Messaging
  • File Bartering Process
• Step-by-Step Examples
  • Scenario 1: File Swapping on Local Machine
  • Scenario 2: File Swapping Between Computers
• Troubleshooting

Features

• Peer-to-Peer Communication: Built on libp2p for direct, serverless communication
• Rendezvous Discovery: Easily find other peers on the network
• Global Chat Room: Message with all connected peers
• Private Messaging: Establish direct connections with specific peers
• Secure File Exchange: End-to-end encryption using age cryptography
• File Bartering: Trade files with other users in a negotiated exchange

Requirements

• Rust
• Cargo package manager

Installation

1. Clone the repository:

   git clone https://eng-git.canterbury.ac.nz/san177/p2p-file-swapping-assignment2.git
   cd p2p-file-swapping-assignment2
   

2. Build the application:

   cargo build
   

Command Line Parameters

Parameter	Description
--run-rendezvous-server	Start the application as a rendezvous server for peer discovery
--port <PORT>	Specify a custom port to listen on (OPTIONAL, default: random available port)
--username <NAME>	Set your display name in the network (default: "Anonymous")
--peer <MULTIADDR>	Connect directly to a peer using their multiaddress (OPTIONAL used for testing)
--rendezvous-server <ADDR>	Connect to a specific rendezvous server by multiaddress (OPTIONAL used for testing)

Running the Application

Starting the Rendezvous Server

The rendezvous server facilitates peer discovery and must be running for peers to find each other:

cargo run -- --run-rendezvous-server

You can specify a custom port:

cargo run -- --run-rendezvous-server --port 50002

When the server starts, it automatically creates an .env file containing its connection details that is used by the clinet to connect to the server.

Starting Client Applications

To start a client and join the network:

cargo run -- --username YourName

By default, the client looks for a rendezvous server address in the .env file. You can specify a server manually:

cargo run -- --username YourName --rendezvous-server /ip4/192.168.1.5/tcp/50002/p2p/ExamplePeerId

Multiple Computer Setup (Same Network)

To connect peers across different computers:

1. Start the rendezvous server on Computer A:

   cargo run -- --run-rendezvous-server
   

2. Note the server's multiaddress in the console output or check the .env file on Computer A.

3. Copy the .env file from Computer A to Computer B, or manually specify the server's multiaddress when starting the client on Computer B.

4. Start clients on both computers:

   cargo run -- --username ComputerAUser  # On Computer A
   cargo run -- --username ComputerBUser  # On Computer B
   

Application Usage

Global Chat Commands

Once connected, you'll be placed in the global chat room with these commands:

• /help - Show available commands
• /peers - List connected peers
• /dm <username or peer_id> - Request to direct message with a peer
• /accept - Accept pending direct message request
• /discover - Manually discover peers through the rendezvous server (used for testing purposes)
• /quit - Leave the chat room and exit the application

To send a message to everyone, simply type your text and press Enter.

Direct Messaging

Direct messaging enables private conversations and file exchanges:

1. Starting a DM Session:

   • From the global chat room, use /dm <username or peer_id>
   • The recipient must accept with /accept
   • The initiator needs to press Enter to join the session

2. DM Session Commands:

   • /barter <offering_file> <requesting_file> - Propose a file exchange
   • /accept - Accept the latest barter proposal
   • /decline - Decline the latest barter proposal
   • /peers - List connected peers
   • /return - Return to the main chat room
   • /help - Show available commands

   You can also type regular messages to chat with your partner.

File Bartering Process

The bartering system allows secure file exchanges:

1. Propose a Barter:
   • Use /barter <your_file> <their_file> to offer your file in exchange for theirs (make sure files do not contain a space in the name)
2. Accept/Decline:
   • The recipient can type /accept or /decline
3. File Transfer:
   • Files are automatically encrypted before sending
   • Received files are saved with a "received_" prefix (e.g., "received_document.txt")
4. Return to Chat Room:
   • When finished, both users can type /return to go back to the global chat

Step-by-Step Examples

Scenario 1: File Swapping Between All Users on the Same Machine

1. Start the Rendezvous Server:

   cargo run -- --run-rendezvous-server
   

2. Start Client A:

   cargo run -- --username Alice
   

3. Start Client B (in another terminal):

   cargo run -- --username Bob
   

4. Initiate Direct Message (from Alice):

   /dm Bob
   

5. Accept DM Request (Bob):

   /accept
   

   Then Alice should press Enter to engage the session.

6. Propose File Barter (Alice):

   /barter 1.txt 2.txt
   

   This means Alice offers "1.txt" and wants "2.txt" from Bob.

7. Accept Barter (Bob):

   /accept
   

8. Return to Chat Room (both users):

   /return
   

9. Exit Application (both users):

   /quit
   

Scenario 2: File Swapping Between Computers on the Same Network

1. Start the Server (on Computer A):

   cargo run -- --run-rendezvous-server
   

   The server will display its multiaddress and write it to the .env file.

2. Update .env file (on Computer B): Copy the contents of the .env file from Computer A to Computer B, or note the multiaddress displayed in the console.

3. Start Client (on Computer A):

   cargo run -- --username ComputerA
   

4. Start Client (on Computer B):

   cargo run -- --username ComputerB
   

   Or with explicit server address:

   cargo run -- --username ComputerB --rendezvous-server <multiaddress-from-computer-A>
   

5. Follow steps 4-9 from Scenario 1.

Troubleshooting

• Peer Discovery Issues: If you can't see other peers, use the /discover command to manually trigger peer discovery.

• File Access Errors: If you encounter Access denied (os error 5), stop all running instances of the application and run cargo clean.

• Direct Messaging Failures: Both peers must be online and connected to the rendezvous server for direct messaging to work.