Chapter 18. Internet Protocol Version 4 (IPv4): Concepts
This chapter explains what the IP protocol is responsible for, and provides a discussion of the IP header fields that support these activities and the impact of these responsibilities on possible implementations. While the chapter discusses some of the choices made in Linux, implementation details are covered in subsequent chapters.
It would be interesting to show how the protocols of the IPsec security suite have been integrated with the IP protocol, but I could not include this topic for lack of space. However, we will sometimes see how the presence of IPsec transformations influences the implementation of core routines.