Answer Happy

Objectives: In this assignment, you will learn about programming
with sockets by implementing a modified version of the File
Transfer Protocol (FTP) for transferring files between two
machines. The purpose of this assignment is to introduce you to the
socket programming API as well as a variety of operating system
concepts that are widely used in the construction of networked
applications. Recommendations & Rules:  The application must
be written in C/C++ in Linux Platform.  Application should operate
in concurrent mode. (So, application serve more than one user at a
time)  Don’t use any special library for protocols when coding.
Write your own functions if it’s necessary.  Unless otherwise
explicitly specified, all written assignments or code that is
submitted is to be entirely the student’s own work. Using any code
or copying any assignment from others is strictly prohibited
without advance prior permission from the instructor.  All
students’ work is their own. Students who do share their work with
others are as responsible for academic dishonesty as the student
receiving the material.  Students who encourage others to cheat or
plagiarize, or students who are aware of plagiarism or cheating and
do not report it are also participating in academically dishonest
behaviour.  In this case (academically dishonest behaviour),
students to be punished with no grade. Project Overview: You will
first write a server program that allows users (clients) to upload
and download files to and from a specified directory. The server
should be run as following arguments: #serverapplication -d
directory -p port -u password -d: Specify running directory which
files to be accessed/modified/erased -p: Define server port number
-u: Password file that uses delimiter separated format which is
delimiter is “:”
(https://en.wikipedia.org/wiki/Delimiterseparated_values) For
example, $ server -d /home/student/files -p 1888 -u password.cfg
File server listening on localhost port 1888 After the server has
started, it simply spins in an infinite loop waiting for incoming
connections until you decide to stop it.
To connect to the server, you can use putty or nc as client for
testing. Once the client has connected to the server, it should
allow the user to interactively get a directory listing, download
and upload files, and close the connection. For example: $ nc
localhost 1888 Welcome to Bob's file server. USER test test123 200
User test granted to access. LIST a.out 5876 client 9130 client.c
580 . GET client.c #include #include main() { } . GET foobar 404
File foobar not found. PUT test This is text message that put as
example . 200 44 Byte test file retrieved by server and was saved.
LIST a.out 5876 client 9130 client.c 580 test 44 . DEL a.out 200
File a.out deleted. DEL nofile 404 File nofile is not on the
server. QUIT Goodbye! $ First, the server must be able to handle
multiple client connections (all of which might be active at any
given time). Protocol This version of FTP will be slight variation
of the FTP protocol implemented over a TCP connection which is
guaranteed to be reliable. Commands The client and server will
communicate with each other by sending ASCII Commands as it given
above. You should implement following commands:
USER Server should handle simple user and password
authentication from password file. Password file should look like
as it given below: alice:qwerty bob:2021.sockets If user name and
password match server should give “200” response and allow
following commands otherwise should give Error code like “400 User
not found”. If user not found client only should use command USER
or QUIT. USER test test100 200 User test granted to access. USER
nobody xxx 400 User not found. Please try with another user. If
user and password is Okay server should accept following commands:
LIST If client gives this command in this case server should list
filenames and file sizes to client. And after files listed list
should terminated with “.”. Filename1 X Filename2 Y Filename3 Z .
GET If client gives this command in this case server should read
file content of filename and send content to client side. Also,
after file content dumped it should terminate with “\r\n.\r\n”. If
file is not found server should give 404 Error. GET file This is
file content. . GET foobar 404 File foobar not found. PUT If client
gives this command in this case server should read file content
from client and save to server side. Client should terminate file
with “\r\n.\r\n”. After server take file should give message 200
and report how much Byte transferred and saved on server side. If
server can not save file should give 400 Error
PUT test This is text message that put as example . 200 44 Byte
test file retrieved by server and was saved. PUT test 400 File
cannot save on server side
DEL If client gives this command in this case server should
delete file from server side. If its succeeded server should give
200 messages otherwise should give 404. DEL a.out 200 File a.out
deleted. DEL nofile 404 File nofile is not on the server. QUIT If
client gives this command in this case server should give goodbye
message and terminates the client connection. QUIT Goodbye!