MyNetcat program

Introduction

In this project, we developed our own netcat program. This program supports open communications across various protocols, enabling routing of standard input (stdin) and standard output (stdout) through socket file descriptors based on the specified flags. This allows us to facilitate communication between users by opening clients and servers.

Authors

This project was developed collaboratively by:

• Gal Ben Ami
• Chanan Helman

Flags

1. -e: Executes a shell command
2. -i: Gets input from a socket.
3. -o: Directs the output to a socket.
4. -b: Sends input and output to the same socket.
5. -t: Sets a timeout for the execution of the program when using the UDP protocol.

Protocols

This program supports four types of protocols:

1. TCP
2. UDP
3. UNIX Domain Socket Stream
4. UNIX Domain Socket Datagram

You can also mix protocols, for example, by opening a UDP server and connecting with a TCP client.

Note: All datagram sockets (UDP and UDS datagram) will wait for dummy input from the client to accept the connection before starting the execution of the program.

How to use

First, clone the repository using the following command:

git clone https://github.com/chanan-hash/OS-Ex2.git

Each folder has its own Makefile for each step. The final version is in the Q6 folder, which includes all the protocols. A recursive Makefile is also available if needed.

sketch for the commands

To use the sockets, follow this format after the flag:

1. TCP server: TCPS<PORT>
2. TCP client: TCPC<HOST>,<PORT>
3. UDP server: UDPS<PORT>
4. UDP client: UDPC<HOST>,<PORT>
5. UDS stream server: UDSSS<PATH>
6. UDS stream client: UDSCS<PATH>
7. UDS datagram server: UDSSD<PATH>
8. UDS datagram client: UDSCD<PATH>

Testing

To test and communicate with our program, we used Linux netcat to avoid writing separate clients and servers for each protocol. The list of commands and usage instructions are in the Q6 folder under work_list.txt.

-e flag

In the examples below, the -e flag is used to execute a command for a tic-tac-toe game implemented in the ttt.c file in each folder. Executing the command without the -e flag will simply facilitate commuincation between two ends, like a chat.

Command exmpales:

Opening a TCP server and waiting for input from a client. Output goes to stdout:

# server
./mync -e "./ttt 123456789" -i TCPS9876
# client
nc localhost 9876

Oppening a TCP client and wait for a input from a server. output go to the client

#server
nc -l -p 9876
#client
/mync -e "./ttt 123456789" -o TCPC127.0.0.1,9876

For the whole command list you can check in Q6-worklist