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

Multiplexing TCP connections

The socket APIs are blocking by default. When you use accept() to wait for an incoming connection, your program's execution is blocked until a new incoming connection is actually available. When you use recv() to read incoming data, your program's execution blocks until new data is actually available.

In the last chapter, we built a simple TCP server. This server only accepted one connection, and it only read data from that connection once. Blocking wasn't a problem then, because our server had no other purpose than to serve its one and only client.

In the general case, though, blocking I/O can be a significant problem. Imagine that our server from Chapter 2, Getting to Grips with Socket APIs, needed to serve multiple clients. Then, imagine that one slow client connected to it. Maybe this slow client takes a minute before sending its first data. During this minute, our server would simply be waiting on the recv() call to return. If other clients were trying to...