Hands-On Network Programming with C

Learn socket programming in C and write secure and optimized network code

Lewis Van Winkle 지음

Packt(GCO Science) 2019년 05월 13일 출간

작품소개

책소개

▶Book Description
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 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 be ready to overcome challenges in network programming with the powerful C language.

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.

▶What You Will Learn
- Uncover cross-platform socket programming APIs
- Implement techniques for supporting IPv4 and IPv6
- Understand how TCP and UDP connections work over IP
- Discover how hostname resolution and DNS work
- Interface with web APIs using HTTP and HTTPS
- Explore Simple Mail Transfer Protocol (SMTP) for electronic mail transmission
- Apply network programming to the Internet of Things (IoT)

▶Key Features
- Apply your C/C programming skills to build powerful network applications
- Get to grips with a variety of network protocols that allow you to load web pages, send emails, and do much more
- Write portable network code for Windows, Linux, and macOS

▶Who This Book Is For
If you're a developer or a system administrator who wants to get started with network programming, this book is for you. Basic knowledge of C programming is assumed.

목차

▶TABLE of CONTENTS
1. Introducing Networks and Protocols
2. Getting to Grips with Socket APIs
3. An In-Depth Overview of TCP Connections
4. Establishing UDP Connections
5. Hostname Resolution and DNS
6. Building a Simple Web Client
7. Building a Simple Web Server
8. Making Your Program Send Email
9. Loading Secure Web Pages with HTTPS and OpenSSL
10. Implementing a Secure Web Server
11. Establishing SSH Connections with libssh
12. Network Monitoring and Security
13. Socket Programming Tips and Pitfalls
14. Web Programming for the Internet of Things

책 속으로

▶What this book covers
- Chapter 1, Introducing Networks and Protocols, introduces the important concepts related to networking. This chapter includes example programs to determine your IP address pragmatically.

- Chapter 2, Getting to Grips with Socket APIs, introduces socket programming APIs and has you build your first networked program―a tiny web server.

- Chapter 3, An In-Depth Overview of TCP Connections, focuses on programming TCP sockets. In this chapter, example programs are developed for both the client and server sides.

- Chapter 4, Establishing UDP Connections, covers programming with User Datagram Protocol (UDP) sockets.

- Chapter 5, Hostname Resolution and DNS, explains how hostnames are translated into IP addresses. In this chapter, we build an example program to perform manual DNS query lookups using UDP.

- Chapter 6, Building a Simple Web Client, introduces HTTP―the protocol that powers websites. We dive right in and build an HTTP client in C.

- Chapter 7, Building a Simple Web Server, describes how to construct a fully functional web server in C. This program is able to serve a static website to any modern web browser.

- Chapter 8, Making Your Program Send Email, describes Simple Mail Transfer Protocol (SMTP)―the protocol that is powering email. In this chapter, we develop a program that can send email over the internet.

- Chapter 9, Loading Secure Web Pages with HTTPS and OpenSSL, explores TLS―the protocol that secures web pages. In this chapter, we develop an HTTPS client that is capable of downloading web pages securely.

- Chapter 10, Implementing a Secure Web Server, continues on the security theme and explores the construction of a secure HTTPS web server.

- Chapter 11, Establishing SSH Connections with libssh, continues with the secure protocol theme. The use of Secure Shell (SSH) is covered to connect to a remote server, execute commands, and download files securely.

- Chapter 12, Network Monitoring and Security, discusses the tools and techniques used to test network functionality, troubleshoot problems, and eavesdrop on insecure communication protocols.

- Chapter 13, Socket Programming Tips and Pitfalls, goes into detail about TCP and addresses many important edge cases that appear in socket programming. The techniques covered are invaluable for creating robust network programs.

- Chapter 14, Web Programming for the Internet of Things, gives an overview of the design and programming for Internet of Things (IoT) applications.

- Appendix A, Answers to Questions, provides answers to the comprehension questions given at the end of each chapter.

- Appendix B, Setting Up Your C Compiler on Windows, gives instructions for setting up a development environment on Windows that is needed for compiling all of the example programs in this book.

- Appendix C, Setting Up Your C Compiler on Linux, provides the setup instructions for preparing your Linux computer to be capable of compiling all of the example programs in this book.

- Appendix D, Setting Up Your C Compiler on macOS, gives step-by-step instructions for configuring your macOS system to be capable of compiling all of the example programs in this book.

- Appendix E, Example Programs, lists each example program, by chapter, included in this book's code repository.

출판사 서평

▶ Preface
Packt first contacted me about writing this book nearly a year ago. It's been a long journey, harder than I anticipated at times, and I've learned a lot. The book you hold now is the culmination of many long days, and I'm proud to finally present it.

I think C is a beautiful programming language. No other language in everyday use gets you as close to the machine as C does. I've used C to program 8-bit microcontrollers with only 16 bytes of RAM, just the same as I've used it to program modern desktops with multi-core, multi-GHz processors. It's truly remarkable that C works efficiently in both contexts.

Network programming is a fun topic, but it's also a very deep one; a lot is going on at many levels. Some programming languages hide these abstractions. In the Python programming language, for example, you can download an entire web page using only one line of code. This isn't the case in C! In C, if you want to download a web page, you have to know how everything works. You need to know sockets, you need to know Transfer Control Protocol (TCP), and you need to know HTTP. In C network programming, nothing is hidden.

C is a great language to learn network programming in. This is not only because we get to see all the details, but also because the popular operating systems all use kernels written in C. No other language gives you the same first-class access as C does. In C, everything is under your control ？ you can lay out your data structures exactly how you want, manage memory precisely as you please, and even shoot yourself in the foot just the way you want.

When I first began writing this book, I surveyed other resources related to learning network programming with C. I found much misinformation ？ not only on the web, but even in print. There is a lot of C networking code that is done wrong. Internet tutorials about C sockets often use deprecated functions and ignore memory safety completely. When it comes to network programming, you can't take the it works so it's good enough programming by-coincidence approach. You have to use reasoning.

In this book, I take care to approach network programming in a modern and safe way. The example programs are carefully designed to work with both IPv4 and IPv6, and they are all written in a portable, operating system-independent way, whenever possible. Wherever there is an opportunity for memory errors, I try to take notice and point out these concerns. Security is too often left as an afterthought. I believe security is important, and it should be planned in the system from the beginning. Therefore, in addition to teaching network basics, this book spends a lot of time working with secure protocols, such as TLS.

I hope you enjoy reading this book as much as I enjoyed writing it.

작가정보

저자(글) Lewis Van Winkle

Lewis Van Winkle is a software programming consultant, entrepreneur, and founder of a successful IoT company. He has over 20 years of programming experience after publishing his first successful software product at age 12. He has over 15 years of programming experience with the C programming language on a variety of operating systems and platforms. He is active in the open-source community and has published several popular open-source programs and libraries-many of them in C. Today, Lewis spends much of his time consulting, where he loves taking on difficult projects that other programmers have given up on. He specializes in network systems, financial systems, machine learning, and interoperation between different programming languages.