Chapter 27. Neighboring Subsystem: Infrastructure

In Chapter 26, we saw the main problems that the neighboring protocols are asked to solve. You also learned that the Linux kernel abstracted out parts of the solution into a common infrastructure shared by various neighboring protocols. In this chapter, we will see how the infrastructure is designed. In particular, we will see how protocols interface to the common infrastructure, how caching and proxying are implemented, and how external subsystems such as higher-layer protocols notify the neighboring protocols about interesting events. We will conclude the chapter with a description of how L3 protocols such as IPv4 actually interface with their neighboring protocols, and how queuing is implemented for buffers awaiting address resolution.