Vkm::Engine::NetConnection Class Reference

One end of one conversation: sequencing, acknowledgement and timing. More...

#include <connection.h>

Public Member Functions
void	open (const NetAddress &peer)
	Point this at peer. Resets everything the last one left.
void	frame (const uint8_t *payload, size_t size, std::vector< uint8_t > &out)
	Wrap payload in a header and hand it back for sending.
bool	accept (const uint8_t *bytes, size_t size, std::vector< uint8_t > &payload, std::vector< uint16_t > &acknowledged)
	Take a datagram that arrived from this peer.
void	refuse ()
	Take back the acknowledgement for the packet just accepted.
void	advance (float seconds)
	Age the silence timer and every unacknowledged packet by seconds of wall clock.
uint16_t	nextSequence () const
	What frame() will stamp on the next packet.
float	roundTrip () const
	Round trip, smoothed.
float	lossFraction () const
	What fraction of the peer's packets never arrived, so far.
float	roundTripVariation () const
	How much that trip varies, smoothed the same way.

Static Public Attributes
static constexpr size_t	HEADER_BYTES = 8
	Bytes of header on every packet: sequence, acknowledgement, and the bitfield of the thirty-two before it.
static constexpr size_t	MAX_PAYLOAD = UdpSocket::MAX_DATAGRAM - HEADER_BYTES
	The most one packet carries past its header: what a datagram leaves.
static constexpr float	TIMEOUT_SECONDS = 5.0f
	How long silence lasts before a peer is given up on.
static constexpr uint16_t	NO_SEQUENCE = 0
	The sequence number nothing ever sends, so a header can say "nothing".

Detailed Description

One end of one conversation: sequencing, acknowledgement and timing.

Every packet carries its sequence, the newest seen the other way, and a bitfield of the thirty-two before that.

Nothing is retransmitted: the next packet says it again, newer. Acknowledgement measures the trip and what a peer holds. A packet older than one already seen is refused, or the world would mix two moments.

Member Function Documentation

frame()

void Vkm::Engine::NetConnection::frame	(	const uint8_t *	payload,
		size_t	size,
		std::vector< uint8_t > &	out )

Wrap payload in a header and hand it back for sending.

The caller owns the socket, which serves every peer of a server.

Parameters

payload	What to carry; may be empty, which is a keep-alive.
size	Its length.
out	Filled with header followed by payload.

accept()

bool Vkm::Engine::NetConnection::accept	(	const uint8_t *	bytes,
		size_t	size,
		std::vector< uint8_t > &	payload,
		std::vector< uint16_t > &	acknowledged )

Take a datagram that arrived from this peer.

Parameters

bytes	The whole datagram, header included.
size	Its length.
payload	Filled with what rode inside it.
acknowledged	Appended with the sequences this datagram confirms, each reported once only.

Returns

False when it is malformed, or older than one already seen.

refuse()

void Vkm::Engine::NetConnection::refuse

(

)

Take back the acknowledgement for the packet just accepted.

A sender reads an acknowledgement as the payload taken (see NetBaseline::confirm), so one that would not decode is un-seen here and described again.

nextSequence()

uint16_t Vkm::Engine::NetConnection::nextSequence ( ) const

inline

What frame() will stamp on the next packet.

For a sender that must remember what that packet claimed.

Returns

The next outgoing sequence.

roundTrip()

float Vkm::Engine::NetConnection::roundTrip ( ) const

inline

Round trip, smoothed.

Returns

Seconds; zero until an acknowledgement has been timed.

lossFraction()

float Vkm::Engine::NetConnection::lossFraction ( ) const

inline

What fraction of the peer's packets never arrived, so far.

Counted from gaps in its sequence numbering; zero until something arrives.

Returns

Lost over sent, in [0, 1).

Member Data Documentation

NO_SEQUENCE

uint16_t Vkm::Engine::NetConnection::NO_SEQUENCE = 0

staticconstexpr

The sequence number nothing ever sends, so a header can say "nothing".

A sender skips it, on the first packet and on every wrap.

---

The documentation for this class was generated from the following file:

• net/transport/connection.h