commit aff77eb1a9dcbdf723d3f8e74e6502e5047bbe63 Author: Andrea Shepard <andrea@torproject.org> Date: Thu Sep 27 15:04:46 2012 -0700 Implement circuitmux_notify_xmit_cells() and circuitmux_move_active_circ_to_tail() helper in circuitmux.c --- src/or/circuitmux.c | 133 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 133 insertions(+), 0 deletions(-) diff --git a/src/or/circuitmux.c b/src/or/circuitmux.c index b5dda9e..deb5bf1 100644 --- a/src/or/circuitmux.c +++ b/src/or/circuitmux.c @@ -141,6 +141,9 @@ circuitmux_make_circuit_active(circuitmux_t *cmux, circuit_t *circ, static void circuitmux_make_circuit_inactive(circuitmux_t *cmux, circuit_t *circ, cell_direction_t direction); +static INLINE void +circuitmux_move_active_circ_to_tail(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 ** @@ -152,6 +155,72 @@ circuitmux_prev_active_circ_p(circuitmux_t *cmux, circuit_t *circ); * Linked list helpers */ +static INLINE void +circuitmux_move_active_circ_to_tail(circuitmux_t *cmux, circuit_t *circ, + cell_direction_t direction) +{ + circuit_t **next_p = NULL, **prev_p = NULL; + circuit_t **next_prev = NULL, **prev_next = NULL; + or_circuit_t *or_circ = NULL; + + tor_assert(cmux); + tor_assert(circ); + + /* Figure out our next_p and prev_p for this cmux/direction */ + if (direction) { + if (direction == CELL_DIRECTION_OUT) { + tor_assert(circ->n_mux == cmux); + next_p = &(circ->next_active_on_n_chan); + prev_p = &(circ->prev_active_on_n_chan); + } else { + or_circ = TO_OR_CIRCUIT(circ); + tor_assert(or_circ->p_mux == cmux); + next_p = &(or_circ->next_active_on_p_chan); + prev_p = &(or_circ->prev_active_on_p_chan); + } + } else { + if (circ->n_mux == cmux) { + next_p = &(circ->next_active_on_n_chan); + prev_p = &(circ->prev_active_on_n_chan); + direction = CELL_DIRECTION_OUT; + } else { + or_circ = TO_OR_CIRCUIT(circ); + tor_assert(or_circ->p_mux == cmux); + next_p = &(or_circ->next_active_on_p_chan); + prev_p = &(or_circ->prev_active_on_p_chan); + direction = CELL_DIRECTION_IN; + } + } + tor_assert(next_p); + tor_assert(prev_p); + + /* Check if this really is an active circuit */ + if ((*next_p == NULL && *prev_p == NULL) && + !(circ == cmux->active_circuits_head || + circ == cmux->active_circuits_tail)) { + /* Not active, no-op */ + return; + } + + /* Check if this is already the tail */ + if (circ == cmux->active_circuits_tail) return; + + /* Okay, we have to move it; figure out next_prev and prev_next */ + if (*next_p) next_prev = circuitmux_prev_active_circ_p(cmux, *next_p); + if (*prev_p) prev_next = circuitmux_next_active_circ_p(cmux, *prev_p); + /* Adjust the previous node's next pointer, if any */ + if (prev_next) *prev_next = *next_p; + /* Otherwise, we were the head */ + else cmux->active_circuits_head = *next_p; + /* Adjust the next node's previous pointer, if any */ + if (next_prev) *next_prev = *prev_p; + /* Adjust our next and prev pointers */ + *next_p = NULL; + *prev_p = cmux->active_circuits_tail; + /* Set the tail to this circuit */ + cmux->active_circuits_tail = circ; +} + static INLINE circuit_t ** circuitmux_next_active_circ_p(circuitmux_t *cmux, circuit_t *circ) { @@ -1175,3 +1244,67 @@ circuitmux_set_num_cells(circuitmux_t *cmux, circuit_t *circ, hashent->muxinfo.cell_count = n_cells; } +/* + * Functions for channel code to call to get a circuit to transmit from or + * notify that cells have been transmitted. + */ + +void +circuitmux_notify_xmit_cells(circuitmux_t *cmux, circuit_t *circ, + unsigned int n_cells) +{ + chanid_circid_muxinfo_t *hashent = NULL; + int becomes_inactive = 0; + + tor_assert(cmux); + tor_assert(circ); + + if (n_cells == 0) return; + + /* + * To handle this, we have to: + * + * 1.) Adjust the circuit's cell counter in the cmux hash table + * 2.) Move the circuit to the tail of the active_circuits linked list + * for this cmux, or make the circuit inactive if the cell count + * went to zero. + * 3.) Call cmux->policy->notify_xmit_cells(), if any + */ + + /* Find the hash entry */ + hashent = circuitmux_find_map_entry(cmux, circ); + /* Assert that we found one */ + tor_assert(hashent); + + /* Adjust the cell counter and assert that we had that many cells to send */ + tor_assert(n_cells <= hashent->muxinfo.cell_count); + hashent->muxinfo.cell_count -= n_cells; + /* Do we need to make the circuit inactive? */ + if (hashent->muxinfo.cell_count == 0) becomes_inactive = 1; + + /* If we aren't making it inactive later, move it to the tail of the list */ + if (!becomes_inactive) { + circuitmux_move_active_circ_to_tail(cmux, circ, + hashent->muxinfo.direction); + } + + /* + * We call notify_xmit_cells() before making the circuit inactive if needed, + * so the policy can always count on this coming in on an active circuit. + */ + if (cmux->policy && cmux->policy->notify_xmit_cells) { + cmux->policy->notify_xmit_cells(cmux, cmux->policy_data, circ, + hashent->muxinfo.policy_data, + n_cells); + } + + /* + * Now make the circuit inactive if needed; this will call the policy's + * notify_circ_inactive() if present. + */ + if (becomes_inactive) { + --(cmux->n_active_circuits); + circuitmux_make_circuit_inactive(cmux, circ, hashent->muxinfo.direction); + } +} +