Preface
Section 1:Getting Started with Network Programming
Chapter 1:Introducing Networks and Protocols
Technical requirements
The internet and C
OSI layer model
TCP/IP layer model
Data encapsulation
Internet Protocol
What is an address?
Domain names
Internet routing
Local networks and address translation
Subnetting and CIDR
Multicast,broadcast,and anycast
Port numbers
Clients and servers
Putting it together
What's your address?
Listing network adapters from C
Listing network adapters on Windows
Listing network adapters on Linux and macOS
Summary
Questions
Chapter 2:Getting to Grips with Socket APIs
Technical requirements
What are sockets?
Socket setup
Two types of sockets
Socket functions
Anatomy of a socket program
TCP program flow
UDP program flow
Berkeley sockets versus Winsock sockets
Header files
Socket data type
Invalid sockets
Closing sockets
Error handling
Our first program
A motivating example
Making it networked
Working with IPv6
Supporting both IPv4 and IPv6
Networking with inetd
Summary
Questions
Chapter 3:An In-Depth Overview of TCP Connections
Technical requirements
Multiplexing TCP connections
Polling non-blocking sockets
Forking and multithreading
The select()function
Synchronous multiplexing with select()
select()timeout
lterating through an fd_set
select()on non-sockets
A TCP client
TCP client code
A TCP server
TCP server code
Building a chat room
Blocking on send()
TCP is a stream protocol
Summary
Questions
Chapter 4:Establishing UDP Connections
Technical requirements
How UDP sockets differ
UDP client methods
UDP server methods
A first UDP client/server
A simple UDP server
A simple UDP client
A UDP server
Summary
Questions
Section 2: An Overview of Application Layer Protocols
Section 3: Understanding Encrypted Protocols and OpenSSL
Section 4: Odds and Ends

网络编程是C语言中一个具有挑战性的主题，通过对套接字编程API的详细阐述，可以使网络编程变得易于理解。本书通过讲解C语言现代网络编程和相关操作系统APl的正确用法，带你步入网络编程之门。
本书涵盖了诸如使用DNS解析主机名等一些核心概念，这些概念对于现代Web的运行至关重要。你将深入研究基本的网络协议：TCP和UDP。本书通过实例来讲解网络范式(例如，客户端一服务器和点对点模型）的基本技术，还将从客户端和服务器的角度研究HTTP和HTTPS（Web页面的相关协议）。
为了与时俱进，我们将应用本书中涉及的概念来深入了解物联网的Web编程。你甚至将应对网络监控和实现安全最佳实践。
阅读本书之后，你会获得处理客户端一服务器应用的经验，并能用C语言实现新的网络程序。
本书中的代码兼容旧版的C99以及最新的C18和C++17标准。本书特别考虑到了编写健壮、可靠、安全的代码，使其能够在不同的操作系统中移植，包括Windows的Winsock套接字以及Linux和macOS的POSIX套接字。