multi_buffer.h File Reference

Detailed Description

Multi-source, multi-sink packet buffer.

The MultiBuffer class implements a multithreaded buffer for packet data, with multiple source and sink ports that operate concurrently. Each port is first-in / first-out, but the aggregate is non-blocking. It is suitable for use in software-defined switches and routers.

To write to the MultiBuffer, instantiate a MultiWriter and use the usual io::Writeable API. To read from the MultiBuffer, instantiate a MultiReader and use the usual io::Readable API. Each MultiBuffer can have any number of attached read or write ports.

By default, each written packet is sent to every attached read port. Child classes can change this by overriding the "deliver" method.

The MultiBuffer operates using a single large pool, allocated separately, that is subdivided into many fine-grained "chunks" (typically ~60 bytes). Internal allocators assign chunks to each port as they write incoming data. A packet is a linked list of such chunks, along with a reference-counter for write-once, read-many operations and garbage collection.

Example supporting two read/write ports:

u8 raw_buffer[16384];
MultiBuffer multi_buff(raw_buffer, sizeof(raw_buffer));
MultiWriter port1_wr(&multi_buff);
MultiWriter port2_wr(&multi_buff);
MultiReaderSimple port1_rd(&multi_buff);
MultiReaderSimple port2_rd(&multi_buff);

Definition in file multi_buffer.h.

#include <satcat5/io_readable.h>
#include <satcat5/io_writeable.h>
#include <satcat5/list.h>
#include <satcat5/types.h>

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Classes
struct	satcat5::io::MultiChunk
	Data-structure representing a single fine-grained memory block. More...
struct	satcat5::io::MultiPacket
	A packet is a linked-list of memory blocks, plus metadata. More...
class	satcat5::io::MultiPacket::Reader
	Barebones class for reading data from a MultiPacket. More...
class	satcat5::io::MultiPacket::Overwriter
	Barebones class for overwriting contents of a MultiPacket. More...
class	satcat5::io::MultiBuffer
	A multi-source, multi-sink packet buffer. More...
class	satcat5::io::MultiReader
	A port for reading from a MultiBuffer object. More...
class	satcat5::io::MultiReaderSimple
	A variant of MultiReader with a simple first-in, first-out queue. More...
class	satcat5::io::MultiReaderPriority
	A variant of MultiReader that follows priority ordering. More...
class	satcat5::io::MultiWriter
	A port for writing to a MultiBuffer object. More...
class	satcat5::io::MultiWriterBypass
	MultiWriter adapter for bypass mode. More...

Macros
#define	SATCAT5_MBUFF_CHUNK   (64 - sizeof(uintptr_t))
#define	SATCAT5_MBUFF_PKTLEN   2048
#define	SATCAT5_MBUFF_RXPKT   32
#define	SATCAT5_MBUFF_TIMEOUT   1500
#define	SATCAT5_MBUFF_USER   8