Course&Laboratory - Computer Networks 2025-2026

Laboratory: Process Management & Inter-process communication via signals
- Concurrent execution of two parent and child processes, using fork() primitive: fork.c
- Example using fork(), execlp(), wait(): exec.c
- Example: when capturing a SIGUSR2 signal, the /etc/services file content will be displayed: sig.c

Laboratory: use of pipes/fifos/socketpairs & duplicate file descriptors
- Example of communication between processes on the same machine using the mechanism provided by FIFO: sendDataFifo.c, recDataFifo.c
- Simulation of shell who | wc, using pipe and duplicate file descriptors using dup(): who_wc.c
- Communication among processes using socketpair(): socketpair.c
Resources: Debugging Linux Programs; Intermediate GDB Tutorial; GDB Fork Debugging

Course:
- [Online] Network Programming (part I). Please follow the meeting schedule posted on Discord.

Laboratory:
- First mandatory homework presentation and uploading. Follow the teacher's specifications and don't upload your homework without her/his approval.
- The use of some commands referring to network level (/sbin/ip, ping, /usr/sbin/traceroute) and transport level (netstat);
- Discussions on fragments from a computer network (don't forget about the links provided at the course): arp-frames.txt, icmp-frames.txt, tcp-frames.txt;

Laboratory: TCP/IP implementation (iterative server and a client).
- TCP iterative server, accompanied by a client. The server receives a name from the client and turns back Hello name. The client takes the name from the standard input, sends it to the server, then expects the server's response:
  servTcpIt.c; cliTcpIt.c; Makefile.

Course:
- Network Programming (part II)
- Example:
  - An UDP iterative server, with a UDP client. The server receives a name from the client and replies with Hello name. The client reads a name from the standard input, sends it to the server, and waits for the reply.
    servUdp.c; cliUdp.c; Makefile.

Course:
- Network Programming (part III)
- Example:
  - A concurrent server that creates a thread for each connected client: servTcpConcTh2.c; cliTCPNr.c
  - A prethreaded server, which uses mutexes for protecting accept(): servTcpPreTh.c; cliTcpNr.c

Laboratory: TCP/IP server and client implementations, with I/O multiplexing using select().
- Example: TCP server and a client application. The server receives a name from the client and replies with Hello name. The client reads the name from the standard input, sends it to the server, then waits for the reply. Sources: servTcpCSel.c; cliTcp.c; Makefile

Laboratory: UDP server and client implementations.
- Example: An UDP iterative server, with a UDP client. The server receives a name from the client and replies with Hello name. The client reads a name from the standard input, sends it to the server, and waits for the reply.
  servUdp.c; cliUdp.c; Makefile.

Laboratory: Second mandatory homework presentation and uploading. Follow the teacher's specifications and don't upload your homework without her/his approval. Please pay attention to the file naming convention.

Optional:
- Optional Course: OOB Communication (RO)
- Example: OOB (out-of-band) data transmission between TCP/IP servers and clients, using select()
  - Example: a TCP server and a client. The clients sends messages to the server, among which, from time to time, some OOB data is sent. The server uses select() to receive standard data and OOB data.
    clientTcpOobSelect.c; serverTcpOobSelect.c;
  - Example: a TCP server and a client. The clients sends messages to the server, among which, from time to time, some OOB data is sent. The server treats the SIGURG signal to identify the OOB data.
    clientTcpOobSigurg.c; serverTcpOobSigurg.c;
  - Example: a TCP server and a client. The clients sends messages to the server, among which, from time to time, some OOB data is sent. The server uses the sockatmark() function to identify the OOB data.
    clientTcpOobSockat.c; serverTcpOobSockat.c;

Course:
- Network Level (II)
Laboratory:
- TCP/IP concurrent server implementation using threads. Example:
  A concurrent server that creates a thread for each connected client: servTcpConcTh2.c; cliTCPNr.c
  A prethreaded server, which uses mutexes for protecting accept(): servTcpPreTh.c; cliTcpNr.c
- Project Development or Project Presentation (and uploading; follow the teacher's specifications and don't upload your project without her/his approval and please pay attention to the file naming convention). Very important: the project can be presented and evaluated only once.

Laboratory: Application development using the following functions: gethostbyname() | getaddrinfo(); gethostbyaddr() | getnameinfo().
- Example: a program that uses gethostbyname(): exgethostbyname.c;
- RPC Example
- Project Development or Project Presentation (and uploading; follow the teacher's specifications and don't upload your project without her/his approval and please pay attention to the file naming convention). Very important: the project can be presented and evaluated only once.

Laboratory: Project Presentation and uploading. Follow the teacher's specifications and don't upload your project without her/his approval and please pay attention to the file naming convention.

The project is rated as ongoing evaluation and cannot be presented during the evaluation or re-evaluation session.

- Computer Networks -