Greetings to everyone, in this article, we will focus on socket programming in C, for a better fundamental understanding. We will explore the creation of sockets, establishing connections, sending and receiving data, and a high-level interface for client-server applications. By the end of the article, you will have a understanding of socket programming.

You can check full source code here:

https://github.com/BitR13x/SimpleHTTPC

Keep in mind that my code isn’t perfect and can be definitely upgraded, but still it can save you some time.

What is “Socket Programming”?

Socket Programming is a fundamental aspect of computer networking that enables communication between applications on different devices. It provides a low-level interface for exchanging data between processes over a network. The concept of sockets is based on the idea of having a unique address, consisting of an IP address and port number, for each process to identify itself and communicate with other processes.

Types of sockets (stream and datagram)

There are two main types of sockets: stream sockets (TCP) and datagram sockets (UDP). Stream sockets provide a reliable, stream-oriented connection between two processes, while datagram sockets offer a best-effort, datagram-oriented connection.

Creating Sockets

In C, sockets are created using the socket() function, which is a part of the Berkeley sockets API. This function returns a socket descriptor, which is used to identify the socket in future operations. The socket() function takes three arguments: the address family, socket type, and protocol. The address family specifies the type of address used (e.g. IPv4 or IPv6), the socket type defines the type of socket (e.g. stream or datagram), and the protocol sets the specific protocol to be used (e.g. TCP or UDP).

Establishing a Connection

Once the socket is created, a connection can be established between the client and server using the connect() function. The connect() function takes a single argument, the address of the server to connect to, which is specified as a sockaddr structure. The connect() function returns zero on success, or a negative value on failure. After a successful connection, the client and server can begin exchanging data.

Sending and Receiving Data

Data is sent from one socket to another using the send() function. The send() function takes three arguments: the socket descriptor, the data to be sent, and the length of the data. Data is received using the recv() function, which takes four arguments: the socket descriptor, a buffer to store the data, the length of the buffer, and flags. The recv() function returns the number of bytes received, or a negative value on error.

High-Level Interface for Client-Server Applications

While the low-level socket API is useful for simple applications, more complex client-server applications can benefit from the use of a higher-level interface. In C, this is achieved through the use of libraries such as libsocket or libnetwork. These libraries provide a simpler, more abstract interface for creating and managing sockets, as well as functions for handling common tasks such as binding to a port and listening for incoming connections. Using a high-level interface can greatly simplify the process of creating complex client-server applications, allowing developers to focus on the implementation of their application’s specific functionality.

Conclusion

Sockets are essential for creating network applications. Whether you are working on a simple client-server application or a complex networked system, socket programming provides a flexible and efficient way to transfer data over a network.

Thanks for reading! If you enjoyed this article, clap and follow me! Looking forward to seeing you in the future.