Important Structures in the Linux Kernel [2]

socket:

This structure is the basis for the implementation of the BSD socket interface. The system call socket() sets up and initialises the structure.

sk_buff:

This structure manages the individual communications packets arriving and being sent from the host. It buffers the input and output. The structure holds the packets before either sending them onto the network interface for transmission, or sending them onto the higher layers for processing and eventually arriving at the application layer.

INET:

This structure administers the network-specific parts of the sockets. It is required for TCP, UDP and RAW sockets.

proto:

This structure contains a number of operations that are the same for all protocols. It means that the actions only need to be programmed once and avoids implementation errors.

sockaddr(sockaddr_in):

These are necessary to support the different address formats for different address families.