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tor/src/or/circuitmux.c
Nick Mathewson 1a74360c2d Test code for implementation of faster circuit_unlink_all_from_channel 
This contains the obvious implementation using the circuitmux data
structure.  It also runs the old (slow) algorithm and compares
the results of the two to make sure that they're the same.

Needs review and testing.
2014-03-14 11:57:51 -04:00

1908 lines
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/* * Copyright (c) 2012-2013, 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"
#include "relay.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;
/** List of queued destroy cells */
cell_queue_t destroy_cell_queue;
/** Boolean: True iff the last cell to circuitmux_get_first_active_circuit
* returned the destroy queue. Used to force alternation between
* destroy/non-destroy cells.
*
* XXXX There is no reason to think that alternating is a particularly good
* approach -- it's just designed to prevent destroys from starving other
* cells completely.
*/
unsigned int last_cell_was_destroy : 1;
/** Destroy counter: increment this when a destroy gets queued, decrement
* when we unqueue it, so we can test to make sure they don't starve.
*/
int64_t destroy_ctr;
/*
* 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);
/* Static global variables */
/** Count the destroy balance to debug destroy queue logic */
static int64_t global_destroy_ctr = 0;
/* 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);
cell_queue_init(&rv->destroy_cell_queue);
return rv;
}
/**
* Detach all circuits from a circuitmux (use before circuitmux_free())
*
* If <b>detached_out</b> is non-NULL, add every detached circuit_t to
* detached_out.
*/
void
circuitmux_detach_all_circuits(circuitmux_t *cmux, smartlist_t *detached_out)
{
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;
if (detached_out)
smartlist_add(detached_out, circ);
} 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;
if (detached_out)
smartlist_add(detached_out, circ);
} else {
/* Complain and move on */
log_warn(LD_CIRC,
"Circuit %u/channel " U64_FORMAT " had direction == "
"CELL_DIRECTION_IN, but isn't an or_circuit_t",
(unsigned)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 %u (for channel " U64_FORMAT ")",
(unsigned)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 %u)",
U64_PRINTF_ARG(to_remove->chan_id),
(unsigned)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;
}
/** Reclaim all circuit IDs currently marked as unusable on <b>chan</b> because
* of pending destroy cells in <b>cmux</b>.
*
* This function must be called AFTER circuits are unlinked from the (channel,
* circuid-id) map with circuit_unlink_all_from_channel(), but before calling
* circuitmux_free().
*/
void
circuitmux_mark_destroyed_circids_usable(circuitmux_t *cmux, channel_t *chan)
{
packed_cell_t *cell;
int n_bad = 0;
TOR_SIMPLEQ_FOREACH(cell, &cmux->destroy_cell_queue.head, next) {
circid_t circid = 0;
if (packed_cell_is_destroy(chan, cell, &circid)) {
channel_mark_circid_usable(chan, circid);
} else {
++n_bad;
}
}
if (n_bad)
log_warn(LD_BUG, "%d cell(s) on destroy queue did not look like a "
"DESTROY cell.", n_bad);
}
/**
* 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);
}
/*
* We're throwing away some destroys; log the counter and
* adjust the global counter by the queue size.
*/
if (cmux->destroy_cell_queue.n > 0) {
cmux->destroy_ctr -= cmux->destroy_cell_queue.n;
global_destroy_ctr -= cmux->destroy_cell_queue.n;
log_debug(LD_CIRC,
"Freeing cmux at %p with %u queued destroys; the last cmux "
"destroy balance was "I64_FORMAT", global is "I64_FORMAT,
cmux, cmux->destroy_cell_queue.n,
I64_PRINTF_ARG(cmux->destroy_ctr),
I64_PRINTF_ARG(global_destroy_ctr));
} else {
log_debug(LD_CIRC,
"Freeing cmux at %p with no queued destroys, the cmux destroy "
"balance was "I64_FORMAT", global is "I64_FORMAT,
cmux,
I64_PRINTF_ARG(cmux->destroy_ctr),
I64_PRINTF_ARG(global_destroy_ctr));
}
cell_queue_clear(&cmux->destroy_cell_queue);
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 + cmux->destroy_cell_queue.n;
}
/**
* 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.
*/
MOCK_IMPL(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)",
(unsigned)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",
(unsigned)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.
*/
MOCK_IMPL(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 %u on channel " U64_FORMAT " was already active",
(unsigned)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",
(unsigned)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.
*
* If we would rather send a destroy cell, return NULL and set
* *<b>destroy_queue_out</b> to the destroy queue.
*
* If we have nothing to send, set *<b>destroy_queue_out</b> to NULL and
* return NULL.
*/
circuit_t *
circuitmux_get_first_active_circuit(circuitmux_t *cmux,
cell_queue_t **destroy_queue_out)
{
circuit_t *circ = NULL;
tor_assert(cmux);
tor_assert(destroy_queue_out);
*destroy_queue_out = NULL;
if (cmux->destroy_cell_queue.n &&
(!cmux->last_cell_was_destroy || cmux->n_active_circuits == 0)) {
/* We have destroy cells to send, and either we just sent a relay cell,
* or we have no relay cells to send. */
/* XXXX We should let the cmux policy have some say in this eventually. */
/* XXXX Alternating is not a terribly brilliant approach here. */
*destroy_queue_out = &cmux->destroy_cell_queue;
cmux->last_cell_was_destroy = 1;
} else 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;
}
cmux->last_cell_was_destroy = 0;
} else {
tor_assert(cmux->n_cells == 0);
tor_assert(cmux->destroy_cell_queue.n == 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);
}
/**
* Notify the circuitmux that a destroy was sent, so we can update
* the counter.
*/
void
circuitmux_notify_xmit_destroy(circuitmux_t *cmux)
{
tor_assert(cmux);
--(cmux->destroy_ctr);
--(global_destroy_ctr);
log_debug(LD_CIRC,
"Cmux at %p sent a destroy, cmux counter is now "I64_FORMAT", "
"global counter is now "I64_FORMAT,
cmux,
I64_PRINTF_ARG(cmux->destroy_ctr),
I64_PRINTF_ARG(global_destroy_ctr));
}
/*
* 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);
}
}
/*DOCDOC */
void
circuitmux_append_destroy_cell(channel_t *chan,
circuitmux_t *cmux,
circid_t circ_id,
uint8_t reason)
{
cell_t cell;
memset(&cell, 0, sizeof(cell_t));
cell.circ_id = circ_id;
cell.command = CELL_DESTROY;
cell.payload[0] = (uint8_t) reason;
cell_queue_append_packed_copy(NULL, &cmux->destroy_cell_queue, 0, &cell,
chan->wide_circ_ids, 0);
/* Destroy entering the queue, update counters */
++(cmux->destroy_ctr);
++global_destroy_ctr;
log_debug(LD_CIRC,
"Cmux at %p queued a destroy for circ %u, cmux counter is now "
I64_FORMAT", global counter is now "I64_FORMAT,
cmux, circ_id,
I64_PRINTF_ARG(cmux->destroy_ctr),
I64_PRINTF_ARG(global_destroy_ctr));
/* XXXX Duplicate code from append_cell_to_circuit_queue */
if (!channel_has_queued_writes(chan)) {
/* There is no data at all waiting to be sent on the outbuf. Add a
* cell, so that we can notice when it gets flushed, flushed_some can
* get called, and we can start putting more data onto the buffer then.
*/
log_debug(LD_GENERAL, "Primed a buffer.");
channel_flush_from_first_active_circuit(chan, 1);
}
}
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