Book Image

Hands-On Network Programming with C

By : Lewis Van Winkle
Book Image

Hands-On Network Programming with C

By: Lewis Van Winkle

Overview of this book

Network programming enables processes to communicate with each other over a computer network, but it is a complex task that requires programming with multiple libraries and protocols. With its support for third-party libraries and structured documentation, C is an ideal language to write network programs. Complete with step-by-step explanations of essential concepts and practical examples, this C network programming book begins with the fundamentals of Internet Protocol, TCP, and UDP. You’ll explore client-server and peer-to-peer models for information sharing and connectivity with remote computers. The book will also cover HTTP and HTTPS for communicating between your browser and website, and delve into hostname resolution with DNS, which is crucial to the functioning of the modern web. As you advance, you’ll gain insights into asynchronous socket programming and streams, and explore debugging and error handling. Finally, you’ll study network monitoring and implement security best practices. By the end of this book, you’ll have experience of working with client-server applications and be able to implement new network programs in C. The code in this book is compatible with the older C99 version as well as the latest C18 and C++17 standards. You’ll work with robust, reliable, and secure code that is portable across operating systems, including Winsock sockets for Windows and POSIX sockets for Linux and macOS.
Table of Contents (26 chapters)
Title Page
About Packt

A UDP server

It will be useful to look at a UDP server that's been designed to service many connections. Fortunately for us, the UDP socket API makes this very easy.

We will take the motivating example from our last chapter, which was to provide a service that converts all text into uppercase. This is useful because you can directly compare the UDP code from here to the TCP server code from Chapter 3, An In-Depth Overview of TCP Connections.

Our server begins by setting up the socket and binding to our local address. It then waits to receive data. Once it has received a data string, it converts the string into all uppercase and sends it back.

The program flow looks as follows:

If you compare the flow of this program to the TCP server from the last chapter (Chapter 3, An In-Depth Overview of TCP Connections), you will find that it's much simpler. With TCP, we had to use listen() and accept(). With UDP, we skip those calls and go straight into receiving data with recvfrom(). With our TCP server...