commit 38fa3b7e4489dafdb74ebef96f5a684c1f29eb1e Author: Andrea Shepard andrea@torproject.org Date: Wed Sep 26 15:04:29 2012 -0700
Implement circuitmux_make_circuit_inactive(), circuitmux_make_circuit_active() and linked list helper functions in circuitmux.c --- src/or/circuitmux.c | 239 ++++++++++++++++++++++++++++++++++++++++++++++++--- 1 files changed, 227 insertions(+), 12 deletions(-)
diff --git a/src/or/circuitmux.c b/src/or/circuitmux.c index 61fd30d..77bb568 100644 --- a/src/or/circuitmux.c +++ b/src/or/circuitmux.c @@ -85,7 +85,7 @@ struct circuitmux_s { * 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; + struct circuit_t *active_circuits_head, *active_circuits_tail;
/* * Priority queue of cell_ewma_t for circuits with queued cells waiting @@ -140,10 +140,50 @@ static INLINE unsigned int chanid_circid_entry_hash(chanid_circid_muxinfo_t *a); static chanid_circid_muxinfo_t * circuitmux_find_map_entry(circuitmux_t *cmux, circuit_t *circ); +static void +circuitmux_make_circuit_active(circuitmux_t *cmux, circuit_t *circ, + cell_direction_t direction); +static void +circuitmux_make_circuit_inactive(circuitmux_t *cmux, circuit_t *circ, + cell_direction_t direction); +static INLINE circuit_t ** +circuitmux_next_active_circ_p(circuitmux_t *cmux, circuit_t *circ); +static INLINE circuit_t ** +circuitmux_prev_active_circ_p(circuitmux_t *cmux, circuit_t *circ);
/* Function definitions */
/** + * Linked list helpers + */ + +static INLINE circuit_t ** +circuitmux_next_active_circ_p(circuitmux_t *cmux, circuit_t *circ) +{ + tor_assert(cmux); + tor_assert(circ); + + if (circ->n_mux == cmux) return &(circ->next_active_on_n_chan); + else { + tor_assert(TO_OR_CIRCUIT(circ)->p_mux == cmux); + return &(TO_OR_CIRCUIT(circ)->next_active_on_p_chan); + } +} + +static INLINE circuit_t ** +circuitmux_prev_active_circ_p(circuitmux_t *cmux, circuit_t *circ) +{ + tor_assert(cmux); + tor_assert(circ); + + if (circ->n_mux == cmux) return &(circ->prev_active_on_n_chan); + else { + tor_assert(TO_OR_CIRCUIT(circ)->p_mux == cmux); + return &(TO_OR_CIRCUIT(circ)->prev_active_on_p_chan); + } +} + +/** * Helper for chanid_circid_cell_count_map_t hash table: compare the channel * ID and circuit ID for a and b, and return less than, equal to, or greater * than zero appropriately. @@ -225,12 +265,16 @@ circuitmux_detach_all_circuits(circuitmux_t *cmux) if (to_remove->muxinfo.direction == CELL_DIRECTION_OUT) { /* Clear n_mux */ circ->n_mux = NULL; + /* Update active_circuits et al. */ + circuitmux_make_circuit_inactive(cmux, circ, CELL_DIRECTION_OUT); } else if (circ->magic == OR_CIRCUIT_MAGIC) { /* * It has a sensible p_chan and direction == CELL_DIRECTION_IN, * so clear p_mux. */ TO_OR_CIRCUIT(circ)->p_mux = NULL; + /* Update active_circuits et al. */ + circuitmux_make_circuit_inactive(cmux, circ, CELL_DIRECTION_IN); } else { /* Complain and move on */ log_warn(LD_CIRC, @@ -239,8 +283,6 @@ circuitmux_detach_all_circuits(circuitmux_t *cmux) to_remove->circ_id, U64_PRINTF_ARG(to_remove->chan_id)); } - - /* TODO update active_circuits / active_circuit_pqueue */ } else { /* Complain and move on */ log_warn(LD_CIRC, @@ -432,7 +474,6 @@ circuitmux_num_cells_for_circuit(circuitmux_t *cmux, circuit_t *circ) return n_cells; }
- /** * Query total number of available cells on a circuitmux */ @@ -548,14 +589,14 @@ circuitmux_attach_circuit(circuitmux_t *cmux, circuit_t *circ, */ if (hashent->muxinfo.cell_count > 0 && cell_count == 0) { --(cmux->n_active_circuits); + circuitmux_make_circuit_inactive(cmux, circ, direction); } else if (hashent->muxinfo.cell_count == 0 && cell_count > 0) { ++(cmux->n_active_circuits); + circuitmux_make_circuit_active(cmux, circ, direction); } cmux->n_cells -= hashent->muxinfo.cell_count; cmux->n_cells += cell_count; hashent->muxinfo.cell_count = cell_count; - - /* TODO update active_circuits / active_circuit_pqueue */ } else { /* * New circuit; add an entry and update the circuit/active circuit @@ -601,8 +642,6 @@ circuitmux_attach_circuit(circuitmux_t *cmux, circuit_t *circ, circuitmux_make_circuit_active(cmux, circ, direction); } cmux->n_cells += cell_count; - - /* TODO update active_circuits / active_circuit_pqueue */ } }
@@ -651,9 +690,11 @@ circuitmux_detach_circuit(circuitmux_t *cmux, circuit_t *circ) if (hashent) { /* Update counters */ --(cmux->n_circuits); - if (hashent->muxinfo.cell_count > 0) --(cmux->n_active_circuits); + if (hashent->muxinfo.cell_count > 0) { + --(cmux->n_active_circuits); + circuitmux_make_circuit_inactive(cmux, circ, last_searched_direction); + } cmux->n_cells -= hashent->muxinfo.cell_count; - /* TODO update active_circuits / active_circuit_pqueue */
/* Consistency check: the direction must match the direction searched */ tor_assert(last_searched_direction == hashent->muxinfo.direction); @@ -667,6 +708,180 @@ circuitmux_detach_circuit(circuitmux_t *cmux, circuit_t *circ) }
/** + * Make a circuit active; update active list and policy-specific info, but + * we don't mess with the counters or hash table here. + */ + +static void +circuitmux_make_circuit_active(circuitmux_t *cmux, circuit_t *circ, + cell_direction_t direction) +{ + circuit_t **next_active = NULL, **prev_active = NULL, **next_prev = NULL; + circuitmux_t *circuit_cmux = NULL; + channel_t *chan = NULL; + circid_t circ_id; + int already_active; + + tor_assert(cmux); + tor_assert(circ); + tor_assert(direction == CELL_DIRECTION_OUT || + direction == CELL_DIRECTION_IN); + + /* Get the right set of active list links for this direction */ + if (direction == CELL_DIRECTION_OUT) { + next_active = &(circ->next_active_on_n_chan); + prev_active = &(circ->prev_active_on_n_chan); + circuit_cmux = circ->n_mux; + chan = circ->n_chan; + circ_id = circ->n_circ_id; + } else { + next_active = &(TO_OR_CIRCUIT(circ)->next_active_on_p_chan); + prev_active = &(TO_OR_CIRCUIT(circ)->prev_active_on_p_chan); + circuit_cmux = TO_OR_CIRCUIT(circ)->p_mux; + chan = TO_OR_CIRCUIT(circ)->p_chan; + circ_id = TO_OR_CIRCUIT(circ)->p_circ_id; + } + + /* Assert that it is attached to this mux and a channel */ + tor_assert(cmux == circuit_cmux); + tor_assert(chan != NULL); + + /* + * Check if the circuit really was inactive; if it's active, at least one + * of the next_active and prev_active pointers will not be NULL, or this + * circuit will be either the head or tail of the list for this cmux. + */ + already_active = (*prev_active != NULL || *next_active != NULL || + cmux->active_circuits_head == circ || + cmux->active_circuits_tail == circ); + + /* If we're already active, log a warning and finish */ + if (already_active) { + log_warn(LD_CIRC, + "Circuit %d on channel " U64_FORMAT " was already active", + circ_id, U64_PRINTF_ARG(chan->global_identifier)); + return; + } + + /* + * This is going at the head of the list; if the old head is not NULL, + * then its prev pointer should point to this. + */ + *next_active = cmux->active_circuits_head; /* Next is old head */ + *prev_active = NULL; /* Prev is NULL (this will be the head) */ + if (cmux->active_circuits_head) { + /* The list had an old head; update its prev pointer */ + next_prev = + circuitmux_prev_active_circ_p(cmux, cmux->active_circuits_head); + tor_assert(next_prev); + *next_prev = circ; + } else { + /* The list was empty; this becomes the tail as well */ + cmux->active_circuits_tail = circ; + } + /* This becomes the new head of the list */ + cmux->active_circuits_head = circ; + + /* TODO policy-specific notifications */ +} + +/** + * Make a circuit inactive; update active list and policy-specific info, but + * we don't mess with the counters or hash table here. + */ + +static void +circuitmux_make_circuit_inactive(circuitmux_t *cmux, circuit_t *circ, + cell_direction_t direction) +{ + circuit_t **next_active = NULL, **prev_active = NULL; + circuit_t **next_prev = NULL, **prev_next = NULL; + circuitmux_t *circuit_cmux = NULL; + channel_t *chan = NULL; + circid_t circ_id; + int already_inactive; + + tor_assert(cmux); + tor_assert(circ); + tor_assert(direction == CELL_DIRECTION_OUT || + direction == CELL_DIRECTION_IN); + + /* Get the right set of active list links for this direction */ + if (direction == CELL_DIRECTION_OUT) { + next_active = &(circ->next_active_on_n_chan); + prev_active = &(circ->prev_active_on_n_chan); + circuit_cmux = circ->n_mux; + chan = circ->n_chan; + circ_id = circ->n_circ_id; + } else { + next_active = &(TO_OR_CIRCUIT(circ)->next_active_on_p_chan); + prev_active = &(TO_OR_CIRCUIT(circ)->prev_active_on_p_chan); + circuit_cmux = TO_OR_CIRCUIT(circ)->p_mux; + chan = TO_OR_CIRCUIT(circ)->p_chan; + circ_id = TO_OR_CIRCUIT(circ)->p_circ_id; + } + + /* Assert that it is attached to this mux and a channel */ + tor_assert(cmux == circuit_cmux); + tor_assert(chan != NULL); + + /* + * Check if the circuit really was active; if it's inactive, the + * next_active and prev_active pointers will be NULL and this circuit + * will not be the head or tail of the list for this cmux. + */ + already_inactive = (*prev_active == NULL && *next_active == NULL && + cmux->active_circuits_head != circ && + cmux->active_circuits_tail != circ); + + /* If we're already inactive, log a warning and finish */ + if (already_inactive) { + log_warn(LD_CIRC, + "Circuit %d on channel " U64_FORMAT " was already inactive", + circ_id, U64_PRINTF_ARG(chan->global_identifier)); + return; + } + + /* Remove from the list; first get next_prev and prev_next */ + if (*next_active) { + /* + * If there's a next circuit, its previous circuit becomes this + * circuit's previous circuit. + */ + next_prev = circuitmux_prev_active_circ_p(cmux, *next_active); + } else { + /* Else, the tail becomes this circuit's previous circuit */ + next_prev = &(cmux->active_circuits_tail); + } + + /* Got next_prev, now prev_next */ + if (*prev_active) { + /* + * If there's a previous circuit, its next circuit becomes this circuit's + * next circuit. + */ + prev_next = circuitmux_next_active_circ_p(cmux, *prev_active); + } else { + /* Else, the head becomes this circuit's next circuit */ + prev_next = &(cmux->active_circuits_head); + } + + /* Assert that we got sensible values for the next/prev pointers */ + tor_assert(next_prev != NULL); + tor_assert(prev_next != NULL); + + /* Update the next/prev pointers - this removes circ from the list */ + *next_prev = *prev_active; + *prev_next = *next_active; + + /* Now null out prev_active/next_active */ + *prev_active = NULL; + *next_active = NULL; + + /* TODO policy-specific notifications */ +} + +/** * Clear the cell counter for a circuit on a circuitmux */
@@ -705,11 +920,11 @@ circuitmux_set_num_cells(circuitmux_t *cmux, circuit_t *circ, */ if (hashent->muxinfo.cell_count > 0 && n_cells == 0) { --(cmux->n_active_circuits); - /* TODO update active_circuits / active_circuit_pqueue */ + circuitmux_make_circuit_inactive(cmux, circ, hashent->muxinfo.direction); /* Is the old cell count == 0 and the new cell count > 0 ? */ } else if (hashent->muxinfo.cell_count == 0 && n_cells > 0) { ++(cmux->n_active_circuits); - /* TODO update active_circuits / active_circuit_pqueue */ + circuitmux_make_circuit_active(cmux, circ, hashent->muxinfo.direction); }
/* Update hash entry cell counter */