/* * Copyright (c) 2012-2013, The Tor Project, Inc. */
/* See LICENSE for licensing information */

/**
 * \file circuitmux.h
 * \brief Header file for circuitmux.c
 **/

#ifndef TOR_CIRCUITMUX_H
#define TOR_CIRCUITMUX_H

#include "or.h"

typedef struct circuitmux_policy_s circuitmux_policy_t;
typedef struct circuitmux_policy_data_s circuitmux_policy_data_t;
typedef struct circuitmux_policy_circ_data_s circuitmux_policy_circ_data_t;

struct circuitmux_policy_s {
  /* Allocate cmux-wide policy-specific data */
  circuitmux_policy_data_t * (*alloc_cmux_data)(circuitmux_t *cmux);
  /* Free cmux-wide policy-specific data */
  void (*free_cmux_data)(circuitmux_t *cmux,
                         circuitmux_policy_data_t *pol_data);
  /* Allocate circuit policy-specific data for a newly attached circuit */
  circuitmux_policy_circ_data_t *
    (*alloc_circ_data)(circuitmux_t *cmux,
                       circuitmux_policy_data_t *pol_data,
                       circuit_t *circ,
                       cell_direction_t direction,
                       unsigned int cell_count);
  /* Free circuit policy-specific data */
  void (*free_circ_data)(circuitmux_t *cmux,
                         circuitmux_policy_data_t *pol_data,
                         circuit_t *circ,
                         circuitmux_policy_circ_data_t *pol_circ_data);
  /* Notify that a circuit has become active/inactive */
  void (*notify_circ_active)(circuitmux_t *cmux,
                             circuitmux_policy_data_t *pol_data,
                             circuit_t *circ,
                             circuitmux_policy_circ_data_t *pol_circ_data);
  void (*notify_circ_inactive)(circuitmux_t *cmux,
                               circuitmux_policy_data_t *pol_data,
                               circuit_t *circ,
                               circuitmux_policy_circ_data_t *pol_circ_data);
  /* Notify of arriving/transmitted cells on a circuit */
  void (*notify_set_n_cells)(circuitmux_t *cmux,
                             circuitmux_policy_data_t *pol_data,
                             circuit_t *circ,
                             circuitmux_policy_circ_data_t *pol_circ_data,
                             unsigned int n_cells);
  void (*notify_xmit_cells)(circuitmux_t *cmux,
                            circuitmux_policy_data_t *pol_data,
                            circuit_t *circ,
                            circuitmux_policy_circ_data_t *pol_circ_data,
                            unsigned int n_cells);
  /* Choose a circuit */
  circuit_t * (*pick_active_circuit)(circuitmux_t *cmux,
                                     circuitmux_policy_data_t *pol_data);
};

/*
 * Circuitmux policy implementations can subclass this to store circuitmux-
 * wide data; it just has the magic number in the base struct.
 */

struct circuitmux_policy_data_s {
  uint32_t magic;
};

/*
 * Circuitmux policy implementations can subclass this to store circuit-
 * specific data; it just has the magic number in the base struct.
 */

struct circuitmux_policy_circ_data_s {
  uint32_t magic;
};

/*
 * Upcast #defines for the above types
 */

/**
 * Convert a circuitmux_policy_data_t subtype to a circuitmux_policy_data_t.
 */

#define TO_CMUX_POL_DATA(x)  (&((x)->base_))

/**
 * Convert a circuitmux_policy_circ_data_t subtype to a
 * circuitmux_policy_circ_data_t.
 */

#define TO_CMUX_POL_CIRC_DATA(x)  (&((x)->base_))

/* Consistency check */
void circuitmux_assert_okay(circuitmux_t *cmux);

/* Create/destroy */
circuitmux_t * circuitmux_alloc(void);
void circuitmux_detach_all_circuits(circuitmux_t *cmux);
void circuitmux_free(circuitmux_t *cmux);

/* Policy control */
void circuitmux_clear_policy(circuitmux_t *cmux);
const circuitmux_policy_t * circuitmux_get_policy(circuitmux_t *cmux);
void circuitmux_set_policy(circuitmux_t *cmux,
                           const circuitmux_policy_t *pol);

/* Status inquiries */
cell_direction_t circuitmux_attached_circuit_direction(
    circuitmux_t *cmux,
    circuit_t *circ);
int circuitmux_is_circuit_attached(circuitmux_t *cmux, circuit_t *circ);
int circuitmux_is_circuit_active(circuitmux_t *cmux, circuit_t *circ);
unsigned int circuitmux_num_cells_for_circuit(circuitmux_t *cmux,
                                              circuit_t *circ);
unsigned int circuitmux_num_cells(circuitmux_t *cmux);
unsigned int circuitmux_num_circuits(circuitmux_t *cmux);
unsigned int circuitmux_num_active_circuits(circuitmux_t *cmux);

/* Channel interface */
circuit_t * circuitmux_get_first_active_circuit(circuitmux_t *cmux,
                                           cell_queue_t **destroy_queue_out);
void circuitmux_notify_xmit_cells(circuitmux_t *cmux, circuit_t *circ,
                                  unsigned int n_cells);
void circuitmux_notify_xmit_destroy(circuitmux_t *cmux);

/* Circuit interface */
void circuitmux_attach_circuit(circuitmux_t *cmux, circuit_t *circ,
                               cell_direction_t direction);
void circuitmux_detach_circuit(circuitmux_t *cmux, circuit_t *circ);
void circuitmux_clear_num_cells(circuitmux_t *cmux, circuit_t *circ);
void circuitmux_set_num_cells(circuitmux_t *cmux, circuit_t *circ,
                              unsigned int n_cells);

void circuitmux_append_destroy_cell(channel_t *chan,
                                    circuitmux_t *cmux, circid_t circ_id,
                                    uint8_t reason);

#endif /* TOR_CIRCUITMUX_H */