12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364656667 |
- /* * Copyright (c) 2012, The Tor Project, Inc. */
- /* See LICENSE for licensing information */
- /**
- * \file circuitmux.c
- * \brief Circuit mux/cell selection abstraction
- **/
- #include "or.h"
- #include "circuitmux.h"
- /*
- * A circuitmux is a collection of circuits; it tracks which subset
- * of the attached circuits are 'active' (i.e., have cells available
- * to transmit) and how many cells on each. It expoes three distinct
- * interfaces to other components:
- *
- * To channels, which each have a circuitmux_t, the supported operations
- * are:
- *
- * circuitmux_flush_cells():
- *
- * Retrieve a cell from one of the active circuits, chosen according to
- * the circuitmux_t's cell selection policy.
- *
- * circuitmux_unlink_all():
- *
- * The channel is closing down, all circuits must be detached.
- *
- * To circuits, the exposed operations are:
- *
- * TODO
- *
- * To circuit selection policies, the exposed operations are:
- *
- * TODO
- *
- * General status inquiries?
- *
- */
- struct circuitmux_s {
- /*
- * Double-linked ring of circuits with queued cells waiting for room to
- * free up on this connection's outbuf. Every time we pull cells from
- * a circuit, we advance this pointer to the next circuit in the ring.
- */
- struct circuit_t *active_circuits;
- /*
- * Priority queue of cell_ewma_t for circuits with queued cells waiting
- * for room to free up on this connection's outbuf. Kept in heap order
- * according to EWMA.
- *
- * This is redundant with active_circuits; if we ever decide only to use
- * the cell_ewma algorithm for choosing circuits, we can remove
- * active_circuits.
- */
- smartlist_t *active_circuit_pqueue;
- /*
- * The tick on which the cell_ewma_ts in active_circuit_pqueue last had
- * their ewma values rescaled.
- */
- unsigned active_circuit_pqueue_last_recalibrated;
- };
|