Programming Assignment #1: Custom Protocol on top of UDP for Client-Server communication

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 sending information to the server

Custom Protocol are defined, commented, and implemented in customProtocol.h header file and customProtocol.c soure code file

Client myclient send custom data_packet to the Server myserver and wait for a response with ACK_Timer set to 3 seconds. Client sends packets in a sequence of 5 segments.

Server myserver reads in the data_packet from Client myclient and check if the packet contains correct information as defined by the Programming Assignment 01 instruction.

If correct, Server myserver responds with an ACK as a custom ack_packet with the received segment number and other relevant information

If incorrect, Server myserver responds with an REJ as a custom 'reject_packet` with one of the following error cases:

1. Out of Sequence segment number
2. Length Mismatch
3. End of Packet Missing
4. Duplicate Packet (checked by comparing sequence number as specified in instruction)

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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 16 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 compilation and running executables successfully on Santa Clara university's ECC (previously Data Center) Linux Computer

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Run Server

./myserver

Alternatively myserver also supports specifying port number:

./myserver 8080

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/test_input.txt

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

./myclient ./input_files/test_input.txt > ./output_files/test_output_client_noServer.txt

The test_input.txt file in the input_files folder contains two sequences of data-packets, one with all 5 correct packets, and another one with 1 correct packet followed by 4 erroneous data packets showcasing all 4 error cases as specified by the procedure instruction given

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