Lab 1: Socket Programming: netcat part

IMPLEMENTED BY : Puneet Loya(username: ploya) and Suprith Chandrashekharachar(username: suprchan)

The project is implemented in C++11.

The code is modularized into four modules.

netcatPart.cpp : The main file which handles all the network communications like client connect to a server and server reading the data as a buffer.

fileOperationsManager.cpp : File Manager that provides APIs to perform read or write file operations.

optionsManager.cpp : options Manager reads all the command line arguments and fills an option dictionary which stores all the options and their values as key-value pairs.

netcatLogger.cpp: netcatLogger performs the job of printing log statemtents when in verbose mode.

Required Files:

netcatLogger.h
optionsManager.h
netcatLogger.cpp
makefile
netcatPart_altered.cpp
fileOperationsManager.h
netcatPart.cpp
optionsManager.cpp
fileOperationsManager.cpp

Tasks Accomplished:
- Client connection to a remote server using TCP protocol. 
- Sending data from the client to the server via TCP connection.
- Buffering recieved data at the server end.
- Reading from a file at the client end.
- Generating message digest at both client and server end for checking message integrity.
- Writing to a file at the server end.
- Tested for a text transfer of size 39000 bytes. A file was read as an input.
- Suppport for reading from a specific file offset and n number of bytes.  

System Requirements:

C++ Compiler : g++/4.7.2 OR g++/4.8

Operating System : Ubuntu14.04/Redhat

Compiling:

If executing on a silo.cs.indiana.edu machine, please make sure you execute the below command at the shell prompt:

	module load gcc/4.7.2

A makefile is provided to compile the program. 

Just cd to the directory containing all files related to the project. Please refer the above section to find which all files are required.

Execute by typing in "make" at the shell prompt.

Refer the makefile for more details.

Usage:

netcat_part [OPTIONS] dest_ip [file] 
 	-h Print this help screen
 	-v Verbose output 
 	-m "MSG"	Send the message specified on the command line 
 			Warning: if you specify this option, you do not specify a file.
 	-p 		port	Set the port to connect on (dflt: 6767) 
 	-n bytes 	Number of bytes to send, defaults whole file 
 	-o offset 	Offset into file to start sending 
 	-l 		Listen on port instead of connecting and write output to file 
 			and dest_ip refers to which ip to bind to (dflt: localhost)


Examples to run the program: 

To start the server: ./netcat_part -l -p 9000 localhost 

Sample Output: 
 CLIENT MODE : 0
 SERVER MODE : 1
STARTING THE SERVER...
PORT NO: 9000
SERVER IS READY TO ACCEPT CONNECTIONS

To start the client and send a file: ./netcat_part -p 9000 localhost small.txt

Sample Output:
 CLIENT MODE : 1
 SERVER MODE : 0
FILE NAME : small.txtSTATUS 0
READ SUCCESS!. BYTES READ INTO MEMORY: 29PREPARING DIGEST... 

 PROGRAM EXECUTED SUCCESSFULLY

To start the client and send a message in verbose mode: ./netcat_part -v -p 9000 -m "anaconda" localhost

 CLIENT MODE : 1
 SERVER MODE : 0
STATUS 0PREPARING DIGEST... 
SENT DATA : anaconda|733983816d3546364bd82e5bbae19caa73c1f188

 PROGRAM EXECUTED SUCCESSFULLY 


Limitations:

File reading and writing is limited to a txt and eng extensions.
Number of bytes and offset requested must be positive integers.