Custom Protocol on top of UDP for Client-Server communication for server-side access permission identification

COEN 233 Introduction to Computer Networks (SCU W2022)

Author: Benjamin Wang (1179478)

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About this Project

Client using customized protocol on top of UDP protocol for requesting identification from server for access permission to the cellular network.

Client myclient send Access Permission requests, also known as Identification requests, to server using custom subscriber_packet set to Access Permission request mode

Server myserver reads in the access permission request from Client myclient and check the source subscriber number (phone number) and technology type (2G - 5G) against the verification database read from ./input_files/verification_database.txt that also contains the Paid status of the subscriber.

Server myclient respond to the Client myclient based on the verification result with

1. Subscriber Not Paid
2. Subscriber Not Exist
3. Subscriber Access Granted

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Project Structure

Main program files and executables are in the project root folder, containing this readme, myclient, myserver, customProtocol, testing, and Makefile source codes and compiled executables

examples folder has the UDP-server-client tutorial codes I based my programming assignment off of

input_files contain the input files used for testing myclient and myserver's verification database

output_files contain the output files generated from myclient and myserver executions, their converted PDF version, and finally screenshots within a sub-folder screenshots

instruction contain the instruction docx and PDFs for COEN 233 Programming Assignment 02

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How to Compile the Code

Use the provided Makefile to compile the code, preferrably after clearing compiled executables first.

make

or better yet:

make clean && make

Note that verbose debugging mode can be activated by not commenting out line 18 of customProtocol.h: // #define DEBUGGING 0 before compilation

Individual compilation options are also available within the Makefile

How to Run the Code

Open two terminals on the same computer. By default Port number 8080 and host "localhost" are used. Navigate to project's main folder first!

Tested successfully (compilation and running executables) on my own PC and SCU's ECC Linux computer.

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Run Server

./myserver

Alternatively myserver also supports specifying port number or port number and verification database filename together:

./myserver 8080

or,

./myserver 8080 ./input_files/verification_database.txt

Note that since this simple implementation of myserver runs the while-loop indefinitely, the user will have to quit myserver by keyboard interrupt such as

Ctrl + C

This also means you can't redirect the command line outputs to an output-file, so that have to be done manually

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Run Client

Must give an input file as argument:

./myclient ./input_files/access_permission_requests.txt

To save output to an output file, preferrably in the output_files folder,

./myclient ./input_files/access_permission_requests.txt > ./output_files/client_output.txt 

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