Source Code Guide

Work in progress, collects names used throughout the source code and gives some added meaning

Ouroboros index of commonly used variable names

type	name	Description
struct shm_du_buff *	sdb	shared memory (shm) data unit (du) buffer. The ouroboros 'flavored' skb. An sdb is a (fixed size) buffer that contains the actual packet data and room for packet headers (and packet tails such as CRC), in addition to some metadata for managing the buffer (head and tail offset to the start of the packet, total size of the buffer, ...). The term 'data unit' stems from the OSI SDU (service data unit) and PDU (protocol data unit), which were adopted by RINA.
int	fd	flow descriptor. It's the flow analogue to a file descriptor.
struct shm_rbuff *	tx_rb, rx_rb, rb	ring buffer. These ring buffers are (small) ring buffers that are shared between 2 processes, used to efficiently move packets through the local pipeline. They pass an index that points to an sdb in the rdrbuff, and are the entry and exit structures with which the application (either a user application or an IPCP) interacts with the end-to-end flow. Writing happens to the transmit ring buffer tx_rb, reading from the receive ring buffer rx_rb.
struct shm_rdrbuff *	rdrb	random deletion ring buffer, This is the block of memory in which Ouroboros stores actual packet data (and metadata) in a (ring buffer) of sdbs. Packets are allocated at the head of the ringbuffer and removed from the tail. Packets are marked on deletion, and deleting the tail causes a cleanup operation of all marked packets. Basically a quick-and-dirty memory allocator that needs to be replaced with something more efficient.
size_t	idx	This idx is an index in the packet buffer (rdrbuff) and used to calculate the location of the packet in reference the base pointer at which the rdrbuff is mapped into each process' memory space.