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Diffstat (limited to 'src/or/circuitmux.c')
| -rw-r--r-- | src/or/circuitmux.c | 1745 |
1 files changed, 1745 insertions, 0 deletions
diff --git a/src/or/circuitmux.c b/src/or/circuitmux.c new file mode 100644 index 0000000000..f3b6b7cd7b --- /dev/null +++ b/src/or/circuitmux.c @@ -0,0 +1,1745 @@ +/* * 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 "channel.h" +#include "circuitlist.h" +#include "circuitmux.h" + +/* + * Private typedefs for circuitmux.c + */ + +/* + * Map of muxinfos for circuitmux_t to use; struct is defined below (name + * of struct must match HT_HEAD line). + */ +typedef struct chanid_circid_muxinfo_map chanid_circid_muxinfo_map_t; + +/* + * Hash table entry (yeah, calling it chanid_circid_muxinfo_s seems to + * break the hash table code). + */ +typedef struct chanid_circid_muxinfo_t chanid_circid_muxinfo_t; + +/* + * Anything the mux wants to store per-circuit in the map; right now just + * a count of queued cells. + */ + +typedef struct circuit_muxinfo_s circuit_muxinfo_t; + +/* + * Structures for circuitmux.c + */ + +/* + * 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_get_first_active_circuit(): + * + * Pick one of the circuitmux's active circuits to send cells from. + * + * circuitmux_notify_xmit_cells(): + * + * Notify the circuitmux that cells have been sent on a circuit. + * + * To circuits, the exposed operations are: + * + * circuitmux_attach_circuit(): + * + * Attach a circuit to the circuitmux; this will allocate any policy- + * specific data wanted for this circuit and add it to the active + * circuits list if it has queued cells. + * + * circuitmux_detach_circuit(): + * + * Detach a circuit from the circuitmux, freeing associated structures. + * + * circuitmux_clear_num_cells(): + * + * Clear the circuitmux's cell counter for this circuit. + * + * circuitmux_set_num_cells(): + * + * Set the circuitmux's cell counter for this circuit. + * + * See circuitmux.h for the circuitmux_policy_t data structure, which contains + * a table of function pointers implementing a circuit selection policy, and + * circuitmux_ewma.c for an example of a circuitmux policy. Circuitmux + * policies can be manipulated with: + * + * circuitmux_get_policy(): + * + * Return the current policy for a circuitmux_t, if any. + * + * circuitmux_clear_policy(): + * + * Remove a policy installed on a circuitmux_t, freeing all associated + * data. The circuitmux will revert to the built-in round-robin behavior. + * + * circuitmux_set_policy(): + * + * Install a policy on a circuitmux_t; the appropriate callbacks will be + * made to attach all existing circuits to the new policy. + * + */ + +struct circuitmux_s { + /* Keep count of attached, active circuits */ + unsigned int n_circuits, n_active_circuits; + + /* Total number of queued cells on all circuits */ + unsigned int n_cells; + + /* + * Map from (channel ID, circuit ID) pairs to circuit_muxinfo_t + */ + chanid_circid_muxinfo_map_t *chanid_circid_map; + + /* + * 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_head, *active_circuits_tail; + + /* + * Circuitmux policy; if this is non-NULL, it can override the built- + * in round-robin active circuits behavior. This is how EWMA works in + * the new circuitmux_t world. + */ + const circuitmux_policy_t *policy; + + /* Policy-specific data */ + circuitmux_policy_data_t *policy_data; +}; + +/* + * This struct holds whatever we want to store per attached circuit on a + * circuitmux_t; right now, just the count of queued cells and the direction. + */ + +struct circuit_muxinfo_s { + /* Count of cells on this circuit at last update */ + unsigned int cell_count; + /* Direction of flow */ + cell_direction_t direction; + /* Policy-specific data */ + circuitmux_policy_circ_data_t *policy_data; + /* Mark bit for consistency checker */ + unsigned int mark:1; +}; + +/* + * A map from channel ID and circuit ID to a circuit_muxinfo_t for that + * circuit. + */ + +struct chanid_circid_muxinfo_t { + HT_ENTRY(chanid_circid_muxinfo_t) node; + uint64_t chan_id; + circid_t circ_id; + circuit_muxinfo_t muxinfo; +}; + +/* + * Internal-use #defines + */ + +#ifdef CMUX_PARANOIA +#define circuitmux_assert_okay_paranoid(cmux) \ + circuitmux_assert_okay(cmux) +#else +#define circuitmux_assert_okay_paranoid(cmux) +#endif + +/* + * Static function declarations + */ + +static INLINE int +chanid_circid_entries_eq(chanid_circid_muxinfo_t *a, + chanid_circid_muxinfo_t *b); +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 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 ** +circuitmux_prev_active_circ_p(circuitmux_t *cmux, circuit_t *circ); +static void circuitmux_assert_okay_pass_one(circuitmux_t *cmux); +static void circuitmux_assert_okay_pass_two(circuitmux_t *cmux); +static void circuitmux_assert_okay_pass_three(circuitmux_t *cmux); + +/* Function definitions */ + +/** + * Linked list helpers + */ + +/** + * Move an active circuit to the tail of the cmux's active circuits list; + * used by circuitmux_notify_xmit_cells(). + */ + +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; + circuit_t **tail_next = NULL; + or_circuit_t *or_circ = NULL; + + tor_assert(cmux); + tor_assert(circ); + + circuitmux_assert_okay_paranoid(cmux); + + /* 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; + /* We're out of the list; now re-attach at the tail */ + /* Adjust our next and prev pointers */ + *next_p = NULL; + *prev_p = cmux->active_circuits_tail; + /* Set the next pointer of the tail, or the head if none */ + if (cmux->active_circuits_tail) { + tail_next = circuitmux_next_active_circ_p(cmux, + cmux->active_circuits_tail); + *tail_next = circ; + } else { + cmux->active_circuits_head = circ; + } + /* Set the tail to this circuit */ + cmux->active_circuits_tail = circ; + + circuitmux_assert_okay_paranoid(cmux); +} + +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. + */ + +static INLINE int +chanid_circid_entries_eq(chanid_circid_muxinfo_t *a, + chanid_circid_muxinfo_t *b) +{ + return a->chan_id == b->chan_id && a->circ_id == b->circ_id; +} + +/** + * Helper: return a hash based on circuit ID and channel ID in a. + */ + +static INLINE unsigned int +chanid_circid_entry_hash(chanid_circid_muxinfo_t *a) +{ + return (((unsigned int)(a->circ_id) << 8) ^ + ((unsigned int)((a->chan_id >> 32) & 0xffffffff)) ^ + ((unsigned int)(a->chan_id & 0xffffffff))); +} + +/* Declare the struct chanid_circid_muxinfo_map type */ +HT_HEAD(chanid_circid_muxinfo_map, chanid_circid_muxinfo_t); + +/* Emit a bunch of hash table stuff */ +HT_PROTOTYPE(chanid_circid_muxinfo_map, chanid_circid_muxinfo_t, node, + chanid_circid_entry_hash, chanid_circid_entries_eq); +HT_GENERATE(chanid_circid_muxinfo_map, chanid_circid_muxinfo_t, node, + chanid_circid_entry_hash, chanid_circid_entries_eq, 0.6, + malloc, realloc, free); + +/* + * Circuitmux alloc/free functions + */ + +/** + * Allocate a new circuitmux_t + */ + +circuitmux_t * +circuitmux_alloc(void) +{ + circuitmux_t *rv = NULL; + + rv = tor_malloc_zero(sizeof(*rv)); + rv->chanid_circid_map = tor_malloc_zero(sizeof(*( rv->chanid_circid_map))); + HT_INIT(chanid_circid_muxinfo_map, rv->chanid_circid_map); + + return rv; +} + +/** + * Detach all circuits from a circuitmux (use before circuitmux_free()) + */ + +void +circuitmux_detach_all_circuits(circuitmux_t *cmux) +{ + chanid_circid_muxinfo_t **i = NULL, *to_remove; + channel_t *chan = NULL; + circuit_t *circ = NULL; + + tor_assert(cmux); + /* + * Don't circuitmux_assert_okay_paranoid() here; this gets called when + * channels are being freed and have already been unregistered, so + * the channel ID lookups it does will fail. + */ + + i = HT_START(chanid_circid_muxinfo_map, cmux->chanid_circid_map); + while (i) { + to_remove = *i; + if (to_remove) { + /* Find a channel and circuit */ + chan = channel_find_by_global_id(to_remove->chan_id); + if (chan) { + circ = + circuit_get_by_circid_channel_even_if_marked(to_remove->circ_id, + chan); + if (circ) { + /* Clear the circuit's mux for this direction */ + if (to_remove->muxinfo.direction == CELL_DIRECTION_OUT) { + /* + * Update active_circuits et al.; this does policy notifies, so + * comes before freeing policy data + */ + + if (to_remove->muxinfo.cell_count > 0) { + circuitmux_make_circuit_inactive(cmux, circ, CELL_DIRECTION_OUT); + } + + /* Clear n_mux */ + circ->n_mux = NULL; + } else if (circ->magic == OR_CIRCUIT_MAGIC) { + /* + * Update active_circuits et al.; this does policy notifies, so + * comes before freeing policy data + */ + + if (to_remove->muxinfo.cell_count > 0) { + circuitmux_make_circuit_inactive(cmux, circ, CELL_DIRECTION_IN); + } + + /* + * It has a sensible p_chan and direction == CELL_DIRECTION_IN, + * so clear p_mux. + */ + TO_OR_CIRCUIT(circ)->p_mux = NULL; + } else { + /* Complain and move on */ + log_warn(LD_CIRC, + "Circuit %d/channel " U64_FORMAT " had direction == " + "CELL_DIRECTION_IN, but isn't an or_circuit_t", + to_remove->circ_id, + U64_PRINTF_ARG(to_remove->chan_id)); + } + + /* Free policy-specific data if we have it */ + if (to_remove->muxinfo.policy_data) { + /* + * If we have policy data, assert that we have the means to + * free it + */ + tor_assert(cmux->policy); + tor_assert(cmux->policy->free_circ_data); + /* Call free_circ_data() */ + cmux->policy->free_circ_data(cmux, + cmux->policy_data, + circ, + to_remove->muxinfo.policy_data); + to_remove->muxinfo.policy_data = NULL; + } + } else { + /* Complain and move on */ + log_warn(LD_CIRC, + "Couldn't find circuit %d (for channel " U64_FORMAT ")", + to_remove->circ_id, + U64_PRINTF_ARG(to_remove->chan_id)); + } + } else { + /* Complain and move on */ + log_warn(LD_CIRC, + "Couldn't find channel " U64_FORMAT " (for circuit id %d)", + U64_PRINTF_ARG(to_remove->chan_id), + to_remove->circ_id); + } + + /* Assert that we don't have un-freed policy data for this circuit */ + tor_assert(to_remove->muxinfo.policy_data == NULL); + } + + i = HT_NEXT_RMV(chanid_circid_muxinfo_map, cmux->chanid_circid_map, i); + + /* Free it */ + tor_free(to_remove); + } + + cmux->n_circuits = 0; + cmux->n_active_circuits = 0; + cmux->n_cells = 0; +} + +/** + * Free a circuitmux_t; the circuits must be detached first with + * circuitmux_detach_all_circuits(). + */ + +void +circuitmux_free(circuitmux_t *cmux) +{ + if (!cmux) return; + + tor_assert(cmux->n_circuits == 0); + tor_assert(cmux->n_active_circuits == 0); + + /* + * Free policy-specific data if we have any; we don't + * need to do circuitmux_set_policy(cmux, NULL) to cover + * the circuits because they would have been handled in + * circuitmux_detach_all_circuits() before this was + * called. + */ + if (cmux->policy && cmux->policy->free_cmux_data) { + if (cmux->policy_data) { + cmux->policy->free_cmux_data(cmux, cmux->policy_data); + cmux->policy_data = NULL; + } + } else tor_assert(cmux->policy_data == NULL); + + if (cmux->chanid_circid_map) { + HT_CLEAR(chanid_circid_muxinfo_map, cmux->chanid_circid_map); + tor_free(cmux->chanid_circid_map); + } + + tor_free(cmux); +} + +/* + * Circuitmux policy control functions + */ + +/** + * Remove any policy installed on cmux; all policy data will be freed and + * cmux behavior will revert to the built-in round-robin active_circuits + * mechanism. + */ + +void +circuitmux_clear_policy(circuitmux_t *cmux) +{ + tor_assert(cmux); + + /* Internally, this is just setting policy to NULL */ + if (cmux->policy) { + circuitmux_set_policy(cmux, NULL); + } +} + +/** + * Return the policy currently installed on a circuitmux_t + */ + +const circuitmux_policy_t * +circuitmux_get_policy(circuitmux_t *cmux) +{ + tor_assert(cmux); + + return cmux->policy; +} + +/** + * Set policy; allocate for new policy, detach all circuits from old policy + * if any, attach them to new policy, and free old policy data. + */ + +void +circuitmux_set_policy(circuitmux_t *cmux, + const circuitmux_policy_t *pol) +{ + const circuitmux_policy_t *old_pol = NULL, *new_pol = NULL; + circuitmux_policy_data_t *old_pol_data = NULL, *new_pol_data = NULL; + chanid_circid_muxinfo_t **i = NULL; + channel_t *chan = NULL; + uint64_t last_chan_id_searched = 0; + circuit_t *circ = NULL; + + tor_assert(cmux); + + /* Set up variables */ + old_pol = cmux->policy; + old_pol_data = cmux->policy_data; + new_pol = pol; + + /* Check if this is the trivial case */ + if (old_pol == new_pol) return; + + /* Allocate data for new policy, if any */ + if (new_pol && new_pol->alloc_cmux_data) { + /* + * If alloc_cmux_data is not null, then we expect to get some policy + * data. Assert that we also have free_cmux_data so we can free it + * when the time comes, and allocate it. + */ + tor_assert(new_pol->free_cmux_data); + new_pol_data = new_pol->alloc_cmux_data(cmux); + tor_assert(new_pol_data); + } + + /* Install new policy and new policy data on cmux */ + cmux->policy = new_pol; + cmux->policy_data = new_pol_data; + + /* Iterate over all circuits, attaching/detaching each one */ + i = HT_START(chanid_circid_muxinfo_map, cmux->chanid_circid_map); + while (i) { + /* Assert that this entry isn't NULL */ + tor_assert(*i); + + /* + * Get the channel; since normal case is all circuits on the mux share a + * channel, we cache last_chan_id_searched + */ + if (!chan || last_chan_id_searched != (*i)->chan_id) { + chan = channel_find_by_global_id((*i)->chan_id); + last_chan_id_searched = (*i)->chan_id; + } + tor_assert(chan); + + /* Get the circuit */ + circ = circuit_get_by_circid_channel_even_if_marked((*i)->circ_id, chan); + tor_assert(circ); + + /* Need to tell old policy it becomes inactive (i.e., it is active) ? */ + if (old_pol && old_pol->notify_circ_inactive && + (*i)->muxinfo.cell_count > 0) { + old_pol->notify_circ_inactive(cmux, old_pol_data, circ, + (*i)->muxinfo.policy_data); + } + + /* Need to free old policy data? */ + if ((*i)->muxinfo.policy_data) { + /* Assert that we have the means to free it if we have policy data */ + tor_assert(old_pol); + tor_assert(old_pol->free_circ_data); + /* Free it */ + old_pol->free_circ_data(cmux, old_pol_data, circ, + (*i)->muxinfo.policy_data); + (*i)->muxinfo.policy_data = NULL; + } + + /* Need to allocate new policy data? */ + if (new_pol && new_pol->alloc_circ_data) { + /* + * If alloc_circ_data is not null, we expect to get some per-circuit + * policy data. Assert that we also have free_circ_data so we can + * free it when the time comes, and allocate it. + */ + tor_assert(new_pol->free_circ_data); + (*i)->muxinfo.policy_data = + new_pol->alloc_circ_data(cmux, new_pol_data, circ, + (*i)->muxinfo.direction, + (*i)->muxinfo.cell_count); + } + + /* Need to make active on new policy? */ + if (new_pol && new_pol->notify_circ_active && + (*i)->muxinfo.cell_count > 0) { + new_pol->notify_circ_active(cmux, new_pol_data, circ, + (*i)->muxinfo.policy_data); + } + + /* Advance to next circuit map entry */ + i = HT_NEXT(chanid_circid_muxinfo_map, cmux->chanid_circid_map, i); + } + + /* Free data for old policy, if any */ + if (old_pol_data) { + /* + * If we had old policy data, we should have an old policy and a free + * function for it. + */ + tor_assert(old_pol); + tor_assert(old_pol->free_cmux_data); + old_pol->free_cmux_data(cmux, old_pol_data); + old_pol_data = NULL; + } +} + +/* + * Circuitmux/circuit attachment status inquiry functions + */ + +/** + * Query the direction of an attached circuit + */ + +cell_direction_t +circuitmux_attached_circuit_direction(circuitmux_t *cmux, circuit_t *circ) +{ + chanid_circid_muxinfo_t *hashent = NULL; + + /* Try to find a map entry */ + hashent = circuitmux_find_map_entry(cmux, circ); + + /* + * This function should only be called on attached circuits; assert that + * we had a map entry. + */ + tor_assert(hashent); + + /* Return the direction from the map entry */ + return hashent->muxinfo.direction; +} + +/** + * Find an entry in the cmux's map for this circuit or return NULL if there + * is none. + */ + +static chanid_circid_muxinfo_t * +circuitmux_find_map_entry(circuitmux_t *cmux, circuit_t *circ) +{ + chanid_circid_muxinfo_t search, *hashent = NULL; + + /* Sanity-check parameters */ + tor_assert(cmux); + tor_assert(cmux->chanid_circid_map); + tor_assert(circ); + + /* Check if we have n_chan */ + if (circ->n_chan) { + /* Okay, let's see if it's attached for n_chan/n_circ_id */ + search.chan_id = circ->n_chan->global_identifier; + search.circ_id = circ->n_circ_id; + + /* Query */ + hashent = HT_FIND(chanid_circid_muxinfo_map, cmux->chanid_circid_map, + &search); + } + + /* Found something? */ + if (hashent) { + /* + * Assert that the direction makes sense for a hashent we found by + * n_chan/n_circ_id before we return it. + */ + tor_assert(hashent->muxinfo.direction == CELL_DIRECTION_OUT); + } else { + /* Not there, have we got a p_chan/p_circ_id to try? */ + if (circ->magic == OR_CIRCUIT_MAGIC) { + search.circ_id = TO_OR_CIRCUIT(circ)->p_circ_id; + /* Check for p_chan */ + if (TO_OR_CIRCUIT(circ)->p_chan) { + search.chan_id = TO_OR_CIRCUIT(circ)->p_chan->global_identifier; + /* Okay, search for that */ + hashent = HT_FIND(chanid_circid_muxinfo_map, cmux->chanid_circid_map, + &search); + /* Find anything? */ + if (hashent) { + /* Assert that the direction makes sense before we return it */ + tor_assert(hashent->muxinfo.direction == CELL_DIRECTION_IN); + } + } + } + } + + /* Okay, hashent is it if it was there */ + return hashent; +} + +/** + * Query whether a circuit is attached to a circuitmux + */ + +int +circuitmux_is_circuit_attached(circuitmux_t *cmux, circuit_t *circ) +{ + chanid_circid_muxinfo_t *hashent = NULL; + + /* Look if it's in the circuit map */ + hashent = circuitmux_find_map_entry(cmux, circ); + + return (hashent != NULL); +} + +/** + * Query whether a circuit is active on a circuitmux + */ + +int +circuitmux_is_circuit_active(circuitmux_t *cmux, circuit_t *circ) +{ + chanid_circid_muxinfo_t *hashent = NULL; + int is_active = 0; + + tor_assert(cmux); + tor_assert(circ); + + /* Look if it's in the circuit map */ + hashent = circuitmux_find_map_entry(cmux, circ); + if (hashent) { + /* Check the number of cells on this circuit */ + is_active = (hashent->muxinfo.cell_count > 0); + } + /* else not attached, so not active */ + + return is_active; +} + +/** + * Query number of available cells for a circuit on a circuitmux + */ + +unsigned int +circuitmux_num_cells_for_circuit(circuitmux_t *cmux, circuit_t *circ) +{ + chanid_circid_muxinfo_t *hashent = NULL; + unsigned int n_cells = 0; + + tor_assert(cmux); + tor_assert(circ); + + /* Look if it's in the circuit map */ + hashent = circuitmux_find_map_entry(cmux, circ); + if (hashent) { + /* Just get the cell count for this circuit */ + n_cells = hashent->muxinfo.cell_count; + } + /* else not attached, so 0 cells */ + + return n_cells; +} + +/** + * Query total number of available cells on a circuitmux + */ + +unsigned int +circuitmux_num_cells(circuitmux_t *cmux) +{ + tor_assert(cmux); + + return cmux->n_cells; +} + +/** + * Query total number of circuits active on a circuitmux + */ + +unsigned int +circuitmux_num_active_circuits(circuitmux_t *cmux) +{ + tor_assert(cmux); + + return cmux->n_active_circuits; +} + +/** + * Query total number of circuits attached to a circuitmux + */ + +unsigned int +circuitmux_num_circuits(circuitmux_t *cmux) +{ + tor_assert(cmux); + + return cmux->n_circuits; +} + +/* + * Functions for circuit code to call to update circuit status + */ + +/** + * Attach a circuit to a circuitmux, for the specified direction. + */ + +void +circuitmux_attach_circuit(circuitmux_t *cmux, circuit_t *circ, + cell_direction_t direction) +{ + channel_t *chan = NULL; + uint64_t channel_id; + circid_t circ_id; + chanid_circid_muxinfo_t search, *hashent = NULL; + unsigned int cell_count; + + tor_assert(cmux); + tor_assert(circ); + tor_assert(direction == CELL_DIRECTION_IN || + direction == CELL_DIRECTION_OUT); + circuitmux_assert_okay_paranoid(cmux); + + /* + * Figure out which channel we're using, and get the circuit's current + * cell count and circuit ID; assert that the circuit is not already + * attached to another mux. + */ + if (direction == CELL_DIRECTION_OUT) { + /* It's n_chan */ + chan = circ->n_chan; + cell_count = circ->n_chan_cells.n; + circ_id = circ->n_circ_id; + } else { + /* We want p_chan */ + chan = TO_OR_CIRCUIT(circ)->p_chan; + cell_count = TO_OR_CIRCUIT(circ)->p_chan_cells.n; + circ_id = TO_OR_CIRCUIT(circ)->p_circ_id; + } + /* Assert that we did get a channel */ + tor_assert(chan); + /* Assert that the circuit ID is sensible */ + tor_assert(circ_id != 0); + + /* Get the channel ID */ + channel_id = chan->global_identifier; + + /* See if we already have this one */ + search.chan_id = channel_id; + search.circ_id = circ_id; + hashent = HT_FIND(chanid_circid_muxinfo_map, cmux->chanid_circid_map, + &search); + + if (hashent) { + /* + * This circuit was already attached to this cmux; make sure the + * directions match and update the cell count and active circuit count. + */ + log_info(LD_CIRC, + "Circuit %u on channel " U64_FORMAT " was already attached to " + "cmux %p (trying to attach to %p)", + circ_id, U64_PRINTF_ARG(channel_id), + ((direction == CELL_DIRECTION_OUT) ? + circ->n_mux : TO_OR_CIRCUIT(circ)->p_mux), + cmux); + + /* + * The mux pointer on this circuit and the direction in result should + * match; otherwise assert. + */ + if (direction == CELL_DIRECTION_OUT) tor_assert(circ->n_mux == cmux); + else tor_assert(TO_OR_CIRCUIT(circ)->p_mux == cmux); + tor_assert(hashent->muxinfo.direction == direction); + + /* + * Looks okay; just update the cell count and active circuits if we must + */ + 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; + } else { + /* + * New circuit; add an entry and update the circuit/active circuit + * counts. + */ + log_debug(LD_CIRC, + "Attaching circuit %u on channel " U64_FORMAT " to cmux %p", + circ_id, U64_PRINTF_ARG(channel_id), cmux); + + /* + * Assert that the circuit doesn't already have a mux for this + * direction. + */ + if (direction == CELL_DIRECTION_OUT) tor_assert(circ->n_mux == NULL); + else tor_assert(TO_OR_CIRCUIT(circ)->p_mux == NULL); + + /* Insert it in the map */ + hashent = tor_malloc_zero(sizeof(*hashent)); + hashent->chan_id = channel_id; + hashent->circ_id = circ_id; + hashent->muxinfo.cell_count = cell_count; + hashent->muxinfo.direction = direction; + /* Allocate policy specific circuit data if we need it */ + if (cmux->policy && cmux->policy->alloc_circ_data) { + /* Assert that we have the means to free policy-specific data */ + tor_assert(cmux->policy->free_circ_data); + /* Allocate it */ + hashent->muxinfo.policy_data = + cmux->policy->alloc_circ_data(cmux, + cmux->policy_data, + circ, + direction, + cell_count); + /* If we wanted policy data, it's an error not to get any */ + tor_assert(hashent->muxinfo.policy_data); + } + HT_INSERT(chanid_circid_muxinfo_map, cmux->chanid_circid_map, + hashent); + + /* Set the circuit's mux for this direction */ + if (direction == CELL_DIRECTION_OUT) circ->n_mux = cmux; + else TO_OR_CIRCUIT(circ)->p_mux = cmux; + + /* Make sure the next/prev pointers are NULL */ + if (direction == CELL_DIRECTION_OUT) { + circ->next_active_on_n_chan = NULL; + circ->prev_active_on_n_chan = NULL; + } else { + TO_OR_CIRCUIT(circ)->next_active_on_p_chan = NULL; + TO_OR_CIRCUIT(circ)->prev_active_on_p_chan = NULL; + } + + /* Update counters */ + ++(cmux->n_circuits); + if (cell_count > 0) { + ++(cmux->n_active_circuits); + circuitmux_make_circuit_active(cmux, circ, direction); + } + cmux->n_cells += cell_count; + } + + circuitmux_assert_okay_paranoid(cmux); +} + +/** + * Detach a circuit from a circuitmux and update all counters as needed; + * no-op if not attached. + */ + +void +circuitmux_detach_circuit(circuitmux_t *cmux, circuit_t *circ) +{ + chanid_circid_muxinfo_t search, *hashent = NULL; + /* + * Use this to keep track of whether we found it for n_chan or + * p_chan for consistency checking. + */ + cell_direction_t last_searched_direction; + + tor_assert(cmux); + tor_assert(cmux->chanid_circid_map); + tor_assert(circ); + circuitmux_assert_okay_paranoid(cmux); + + /* See if we have it for n_chan/n_circ_id */ + if (circ->n_chan) { + search.chan_id = circ->n_chan->global_identifier; + search.circ_id = circ->n_circ_id; + hashent = HT_FIND(chanid_circid_muxinfo_map, cmux->chanid_circid_map, + &search); + last_searched_direction = CELL_DIRECTION_OUT; + } + + /* Got one? If not, see if it's an or_circuit_t and try p_chan/p_circ_id */ + if (!hashent) { + if (circ->magic == OR_CIRCUIT_MAGIC) { + search.circ_id = TO_OR_CIRCUIT(circ)->p_circ_id; + if (TO_OR_CIRCUIT(circ)->p_chan) { + search.chan_id = TO_OR_CIRCUIT(circ)->p_chan->global_identifier; + hashent = HT_FIND(chanid_circid_muxinfo_map, + cmux->chanid_circid_map, + &search); + last_searched_direction = CELL_DIRECTION_IN; + } + } + } + + /* + * If hashent isn't NULL, we have a circuit to detach; don't remove it from + * the map until later of circuitmux_make_circuit_inactive() breaks. + */ + if (hashent) { + /* Update counters */ + --(cmux->n_circuits); + if (hashent->muxinfo.cell_count > 0) { + --(cmux->n_active_circuits); + /* This does policy notifies, so comes before freeing policy data */ + circuitmux_make_circuit_inactive(cmux, circ, last_searched_direction); + } + cmux->n_cells -= hashent->muxinfo.cell_count; + + /* Free policy-specific data if we have it */ + if (hashent->muxinfo.policy_data) { + /* If we have policy data, assert that we have the means to free it */ + tor_assert(cmux->policy); + tor_assert(cmux->policy->free_circ_data); + /* Call free_circ_data() */ + cmux->policy->free_circ_data(cmux, + cmux->policy_data, + circ, + hashent->muxinfo.policy_data); + hashent->muxinfo.policy_data = NULL; + } + + /* Consistency check: the direction must match the direction searched */ + tor_assert(last_searched_direction == hashent->muxinfo.direction); + /* Clear the circuit's mux for this direction */ + if (last_searched_direction == CELL_DIRECTION_OUT) circ->n_mux = NULL; + else TO_OR_CIRCUIT(circ)->p_mux = NULL; + + /* Now remove it from the map */ + HT_REMOVE(chanid_circid_muxinfo_map, cmux->chanid_circid_map, hashent); + + /* Free the hash entry */ + tor_free(hashent); + } + + circuitmux_assert_okay_paranoid(cmux); +} + +/** + * 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; + chanid_circid_muxinfo_t *hashent = 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); + /* + * Don't circuitmux_assert_okay_paranoid(cmux) here because the cell count + * already got changed and we have to update the list for it to be consistent + * again. + */ + + /* 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; + + /* Policy-specific notification */ + if (cmux->policy && + cmux->policy->notify_circ_active) { + /* Okay, we need to check the circuit for policy data now */ + hashent = circuitmux_find_map_entry(cmux, circ); + /* We should have found something */ + tor_assert(hashent); + /* Notify */ + cmux->policy->notify_circ_active(cmux, cmux->policy_data, + circ, hashent->muxinfo.policy_data); + } + + circuitmux_assert_okay_paranoid(cmux); +} + +/** + * 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; + chanid_circid_muxinfo_t *hashent = 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); + /* + * Don't circuitmux_assert_okay_paranoid(cmux) here because the cell count + * already got changed and we have to update the list for it to be consistent + * again. + */ + + /* 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; + + /* Policy-specific notification */ + if (cmux->policy && + cmux->policy->notify_circ_inactive) { + /* Okay, we need to check the circuit for policy data now */ + hashent = circuitmux_find_map_entry(cmux, circ); + /* We should have found something */ + tor_assert(hashent); + /* Notify */ + cmux->policy->notify_circ_inactive(cmux, cmux->policy_data, + circ, hashent->muxinfo.policy_data); + } + + circuitmux_assert_okay_paranoid(cmux); +} + +/** + * Clear the cell counter for a circuit on a circuitmux + */ + +void +circuitmux_clear_num_cells(circuitmux_t *cmux, circuit_t *circ) +{ + /* This is the same as setting the cell count to zero */ + circuitmux_set_num_cells(cmux, circ, 0); +} + +/** + * Set the cell counter for a circuit on a circuitmux + */ + +void +circuitmux_set_num_cells(circuitmux_t *cmux, circuit_t *circ, + unsigned int n_cells) +{ + chanid_circid_muxinfo_t *hashent = NULL; + + tor_assert(cmux); + tor_assert(circ); + + circuitmux_assert_okay_paranoid(cmux); + + /* Search for this circuit's entry */ + hashent = circuitmux_find_map_entry(cmux, circ); + /* Assert that we found one */ + tor_assert(hashent); + + /* Update cmux cell counter */ + cmux->n_cells -= hashent->muxinfo.cell_count; + cmux->n_cells += n_cells; + + /* Do we need to notify a cmux policy? */ + if (cmux->policy && cmux->policy->notify_set_n_cells) { + /* Call notify_set_n_cells */ + cmux->policy->notify_set_n_cells(cmux, + cmux->policy_data, + circ, + hashent->muxinfo.policy_data, + n_cells); + } + + /* + * Update cmux active circuit counter: is the old cell count > 0 and the + * new cell count == 0 ? + */ + if (hashent->muxinfo.cell_count > 0 && n_cells == 0) { + --(cmux->n_active_circuits); + hashent->muxinfo.cell_count = n_cells; + 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); + hashent->muxinfo.cell_count = n_cells; + circuitmux_make_circuit_active(cmux, circ, hashent->muxinfo.direction); + } else { + /* + * Update the entry cell count like this so we can put a + * circuitmux_assert_okay_paranoid inside make_circuit_(in)active() too. + */ + hashent->muxinfo.cell_count = n_cells; + } + + circuitmux_assert_okay_paranoid(cmux); +} + +/* + * Functions for channel code to call to get a circuit to transmit from or + * notify that cells have been transmitted. + */ + +/** + * Pick a circuit to send from, using the active circuits list or a + * circuitmux policy if one is available. This is called from channel.c. + */ + +circuit_t * +circuitmux_get_first_active_circuit(circuitmux_t *cmux) +{ + circuit_t *circ = NULL; + + tor_assert(cmux); + + if (cmux->n_active_circuits > 0) { + /* We also must have a cell available for this to be the case */ + tor_assert(cmux->n_cells > 0); + /* Do we have a policy-provided circuit selector? */ + if (cmux->policy && cmux->policy->pick_active_circuit) { + circ = cmux->policy->pick_active_circuit(cmux, cmux->policy_data); + } + /* Fall back on the head of the active circuits list */ + if (!circ) { + tor_assert(cmux->active_circuits_head); + circ = cmux->active_circuits_head; + } + } else tor_assert(cmux->n_cells == 0); + + return circ; +} + +/** + * Notify the circuitmux that cells have been sent on a circuit; this + * is called from channel.c. + */ + +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); + circuitmux_assert_okay_paranoid(cmux); + + 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; + /* Adjust the mux cell counter */ + cmux->n_cells -= n_cells; + + /* 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); + } + + circuitmux_assert_okay_paranoid(cmux); +} + +/* + * Circuitmux consistency checking assertions + */ + +/** + * Check that circuitmux data structures are consistent and fail with an + * assert if not. + */ + +void +circuitmux_assert_okay(circuitmux_t *cmux) +{ + tor_assert(cmux); + + /* + * Pass 1: iterate the hash table; for each entry: + * a) Check that the circuit has this cmux for n_mux or p_mux + * b) If the cell_count is > 0, set the mark bit; otherwise clear it + * c) Also check activeness (cell_count > 0 should be active) + * d) Count the number of circuits, active circuits and queued cells + * and at the end check that they match the counters in the cmux. + * + * Pass 2: iterate the active circuits list; for each entry, + * make sure the circuit is attached to this mux and appears + * in the hash table. Make sure the mark bit is 1, and clear + * it in the hash table entry. Consistency-check the linked + * list pointers. + * + * Pass 3: iterate the hash table again; assert if any active circuits + * (mark bit set to 1) are discovered that weren't cleared in pass 2 + * (don't appear in the linked list). + */ + + circuitmux_assert_okay_pass_one(cmux); + circuitmux_assert_okay_pass_two(cmux); + circuitmux_assert_okay_pass_three(cmux); +} + +/** + * Do the first pass of circuitmux_assert_okay(); see the comment in that + * function. + */ + +static void +circuitmux_assert_okay_pass_one(circuitmux_t *cmux) +{ + chanid_circid_muxinfo_t **i = NULL; + uint64_t chan_id; + channel_t *chan; + circid_t circ_id; + circuit_t *circ; + or_circuit_t *or_circ; + unsigned int circ_is_active; + circuit_t **next_p, **prev_p; + unsigned int n_circuits, n_active_circuits, n_cells; + + tor_assert(cmux); + tor_assert(cmux->chanid_circid_map); + + /* Reset the counters */ + n_circuits = n_active_circuits = n_cells = 0; + /* Start iterating the hash table */ + i = HT_START(chanid_circid_muxinfo_map, cmux->chanid_circid_map); + while (i) { + /* Assert that the hash table entry isn't null */ + tor_assert(*i); + + /* Get the channel and circuit id */ + chan_id = (*i)->chan_id; + circ_id = (*i)->circ_id; + + /* Find the channel and circuit, assert that they exist */ + chan = channel_find_by_global_id(chan_id); + tor_assert(chan); + circ = circuit_get_by_circid_channel_even_if_marked(circ_id, chan); + tor_assert(circ); + /* Clear the circ_is_active bit to start */ + circ_is_active = 0; + + /* Assert that we know which direction this is going */ + tor_assert((*i)->muxinfo.direction == CELL_DIRECTION_OUT || + (*i)->muxinfo.direction == CELL_DIRECTION_IN); + + if ((*i)->muxinfo.direction == CELL_DIRECTION_OUT) { + /* We should be n_mux on this circuit */ + tor_assert(cmux == circ->n_mux); + tor_assert(chan == circ->n_chan); + /* Get next and prev for next test */ + next_p = &(circ->next_active_on_n_chan); + prev_p = &(circ->prev_active_on_n_chan); + } else { + /* This should be an or_circuit_t and we should be p_mux */ + or_circ = TO_OR_CIRCUIT(circ); + tor_assert(cmux == or_circ->p_mux); + tor_assert(chan == or_circ->p_chan); + /* Get next and prev for next test */ + next_p = &(or_circ->next_active_on_p_chan); + prev_p = &(or_circ->prev_active_on_p_chan); + } + + /* + * Should this circuit be active? I.e., does the mux know about > 0 + * cells on it? + */ + circ_is_active = ((*i)->muxinfo.cell_count > 0); + + /* It should be in the linked list iff it's active */ + if (circ_is_active) { + /* Either we have a next link or we are the tail */ + tor_assert(*next_p || (circ == cmux->active_circuits_tail)); + /* Either we have a prev link or we are the head */ + tor_assert(*prev_p || (circ == cmux->active_circuits_head)); + /* Increment the active circuits counter */ + ++n_active_circuits; + } else { + /* Shouldn't be in list, so no next or prev link */ + tor_assert(!(*next_p)); + tor_assert(!(*prev_p)); + /* And can't be head or tail */ + tor_assert(circ != cmux->active_circuits_head); + tor_assert(circ != cmux->active_circuits_tail); + } + + /* Increment the circuits counter */ + ++n_circuits; + /* Adjust the cell counter */ + n_cells += (*i)->muxinfo.cell_count; + + /* Set the mark bit to circ_is_active */ + (*i)->muxinfo.mark = circ_is_active; + + /* Advance to the next entry */ + i = HT_NEXT(chanid_circid_muxinfo_map, cmux->chanid_circid_map, i); + } + + /* Now check the counters */ + tor_assert(n_cells == cmux->n_cells); + tor_assert(n_circuits == cmux->n_circuits); + tor_assert(n_active_circuits == cmux->n_active_circuits); +} + +/** + * Do the second pass of circuitmux_assert_okay(); see the comment in that + * function. + */ + +static void +circuitmux_assert_okay_pass_two(circuitmux_t *cmux) +{ + circuit_t *curr_circ, *prev_circ = NULL, *next_circ; + or_circuit_t *curr_or_circ; + uint64_t curr_chan_id; + circid_t curr_circ_id; + circuit_t **next_p, **prev_p; + channel_t *chan; + unsigned int n_active_circuits = 0; + cell_direction_t direction; + chanid_circid_muxinfo_t search, *hashent = NULL; + + tor_assert(cmux); + tor_assert(cmux->chanid_circid_map); + + /* + * Walk the linked list of active circuits in cmux; keep track of the + * previous circuit seen for consistency checking purposes. Count them + * to make sure the number in the linked list matches + * cmux->n_active_circuits. + */ + curr_circ = cmux->active_circuits_head; + while (curr_circ) { + /* Reset some things */ + chan = NULL; + curr_or_circ = NULL; + next_circ = NULL; + next_p = prev_p = NULL; + direction = 0; + + /* Figure out if this is n_mux or p_mux */ + if (cmux == curr_circ->n_mux) { + /* Get next_p and prev_p */ + next_p = &(curr_circ->next_active_on_n_chan); + prev_p = &(curr_circ->prev_active_on_n_chan); + /* Get the channel */ + chan = curr_circ->n_chan; + /* Get the circuit id */ + curr_circ_id = curr_circ->n_circ_id; + /* Remember the direction */ + direction = CELL_DIRECTION_OUT; + } else { + /* We must be p_mux and this must be an or_circuit_t */ + curr_or_circ = TO_OR_CIRCUIT(curr_circ); + tor_assert(cmux == curr_or_circ->p_mux); + /* Get next_p and prev_p */ + next_p = &(curr_or_circ->next_active_on_p_chan); + prev_p = &(curr_or_circ->prev_active_on_p_chan); + /* Get the channel */ + chan = curr_or_circ->p_chan; + /* Get the circuit id */ + curr_circ_id = curr_or_circ->p_circ_id; + /* Remember the direction */ + direction = CELL_DIRECTION_IN; + } + + /* Assert that we got a channel and get the channel ID */ + tor_assert(chan); + curr_chan_id = chan->global_identifier; + + /* Assert that prev_p points to last circuit we saw */ + tor_assert(*prev_p == prev_circ); + /* If that's NULL, assert that we are the head */ + if (!(*prev_p)) tor_assert(curr_circ == cmux->active_circuits_head); + + /* Get the next circuit */ + next_circ = *next_p; + /* If it's NULL, assert that we are the tail */ + if (!(*next_p)) tor_assert(curr_circ == cmux->active_circuits_tail); + + /* Now find the hash table entry for this circuit */ + search.chan_id = curr_chan_id; + search.circ_id = curr_circ_id; + hashent = HT_FIND(chanid_circid_muxinfo_map, cmux->chanid_circid_map, + &search); + + /* Assert that we have one */ + tor_assert(hashent); + + /* Assert that the direction matches */ + tor_assert(direction == hashent->muxinfo.direction); + + /* Assert that the hash entry got marked in pass one */ + tor_assert(hashent->muxinfo.mark); + + /* Clear the mark */ + hashent->muxinfo.mark = 0; + + /* Increment the counter */ + ++n_active_circuits; + + /* Advance to the next active circuit and update prev_circ */ + prev_circ = curr_circ; + curr_circ = next_circ; + } + + /* Assert that the counter matches the cmux */ + tor_assert(n_active_circuits == cmux->n_active_circuits); +} + +/** + * Do the third pass of circuitmux_assert_okay(); see the comment in that + * function. + */ + +static void +circuitmux_assert_okay_pass_three(circuitmux_t *cmux) +{ + chanid_circid_muxinfo_t **i = NULL; + + tor_assert(cmux); + tor_assert(cmux->chanid_circid_map); + + /* Start iterating the hash table */ + i = HT_START(chanid_circid_muxinfo_map, cmux->chanid_circid_map); + + /* Advance through each entry */ + while (i) { + /* Assert that it isn't null */ + tor_assert(*i); + + /* + * Assert that this entry is not marked - i.e., that either we didn't + * think it should be active in pass one or we saw it in the active + * circuits linked list. + */ + tor_assert(!((*i)->muxinfo.mark)); + + /* Advance to the next entry */ + i = HT_NEXT(chanid_circid_muxinfo_map, cmux->chanid_circid_map, i); + } +} + |