rahulpathak-github / passiveFTP

Simple C++ implementation of passive FTP

Passive File Transfer Protocol

Description

Passive FTP is a variant of the FTP, a network protocol for transmitting files between computers over TCP/IP connections.

Two types of channels have been implemented,

1. Control/Command channel : Used to exchange commands and replies to commands between client and server
2. Data channel : Used to send (recieve) a file to (from) a host

A naive authentication mechanism has also been implemented to make the clients perform R/W operations in a dedicated directory. The program prompts the user to enter username and password, if the entered username does not exist in users.txt file, it is considered a register attempt. The user is registered and a new directory is created for that user. If the username matches an entry in users.txt, the program checks the corresponding password and the attempt is considered login.

The server listens for control channel connection requests on PORT and for data channel connection requests on PORT+1. A control channel is established when a client connects to the server. Data channels are created on request (GET/PUT). This mechanism enables multiple clients to perform multiple GET/PUT operations simultaneously.

Only one control channel exists between a client and the server but multiple data channels may exist. Data channels are closed automatically when the designated file transfer is completed.

Commands Supported

1. GET : Downloads a file from the logged-in user's directory from the server and saves it in the CLIENT directory on the client.

   GET <filename> [-b (for binary mode)] $

2. LIST : Description: List all files present in logged in clients's directory on the server.

   LIST $

3. PUT : Uploads a file from the CLIENT directory from client to the logged-in user's directory on the server.

   PUT <filename> [-b (for binary mode)] $

4. close : Disconnect the client from server.

   close $

Setup and Run

1. Clone this repo

   git clone https://github.com/rahulpathak-github/passiveFTP

2. Run the following command to build and move into the build directory

   cd passiveFTP && sh build.sh && cd build

3. Run the server

   ./server <PORT>

4. Run the client

   ./client <IP> <PORT>

Note: Current implemetation allows only one connection from one IP address.

Author

• Rahul Pathak