Samuel J. Leffler, William N. Joy, Robert S. Fabry, and Michael J. Karels
Computer Systems Research Group
Computer Science Division
Department of Electrical Engineering and Computer Science
University of California, Berkeley
Berkeley, CA 94720
This report describes the internal structure of the networking facilities developed for the 4.4BSD version of the UNIX* operating system for the VAX**. These facilities are based on several central abstractions which structure the external (user) view of network communication as well as the internal (system) implementation.
The report documents the internal structure of the networking system. The ``Berkeley Software Architecture Manual, 4.4BSD Edition'' (PSD:5) provides a description of the user interface to the networking facilities.
Revised June 10, 1993
TABLE OF CONTENTS
1. Introduction
2. Overview
3. Goals
4. Internal address representation
5. Memory management
6. Internal layering 6.1. Socket layer 6.1.1. Socket state 6.1.2. Socket data queues 6.1.3. Socket connection queuing 6.2. Protocol layer(s) 6.3. Network-interface layer 6.3.1. UNIBUS interfaces
7. Socket/protocol interface
8. Protocol/protocol interface 8.1. pr_output 8.2. pr_input 8.3. pr_ctlinput 8.4. pr_ctloutput
9. Protocol/network-interface interface 9.1. Packet transmission 9.2. Packet reception
10. Gateways and routing issues 10.1. Routing tables 10.2. Routing table interface 10.3. User level routing policies
11. Raw sockets 11.1. Control blocks 11.2. Input processing 11.3. Output processing
12. Buffering and congestion control 12.1. Memory management 12.2. Protocol buffering policies 12.3. Queue limiting 12.4. Packet forwarding
13. Out of band data
14. Trailer protocols
Acknowledgements
References