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Split out major functionality of circuit_get_best; rephrase a few booleans

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svn:r1547
This commit is contained in:
Nick Mathewson 2004-04-08 01:55:21 +00:00
parent eaf7c61ebc
commit 60772ec90c
1 changed files with 102 additions and 83 deletions
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185
src/or/circuit.c
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@ -250,7 +250,106 @@ circuit_t *circuit_get_by_conn(connection_t *conn) {
return NULL;
}
/* Dear god this function needs refactoring. */
/* Return 1 iff 'c' could be returned by circuit_get_best.
*/
static int circuit_is_acceptable(circuit_t *circ,
connection_t *conn,
int must_be_open,
uint8_t purpose,
time_t now)
{
routerinfo_t *exitrouter;
if (!circ->cpath)
return 0; /* this circ doesn't start at us */
if (must_be_open && (circ->state != CIRCUIT_STATE_OPEN || !circ->n_conn))
return 0; /* ignore non-open circs */
if (circ->marked_for_close)
return 0;
/* if this circ isn't our purpose, skip. */
if(purpose == CIRCUIT_PURPOSE_C_REND_JOINED && !must_be_open) {
if(circ->purpose != CIRCUIT_PURPOSE_C_ESTABLISH_REND &&
circ->purpose != CIRCUIT_PURPOSE_C_REND_READY &&
circ->purpose != CIRCUIT_PURPOSE_C_REND_JOINED)
return 0;
} else {
if(purpose != circ->purpose)
return 0;
}
if(purpose == CIRCUIT_PURPOSE_C_GENERAL)
if(circ->timestamp_dirty &&
circ->timestamp_dirty+options.NewCircuitPeriod < now)
return 0;
if(conn) {
/* decide if this circ is suitable for this conn */
// if(circ->state == CIRCUIT_STATE_OPEN && circ->n_conn) /* open */
// exitrouter = router_get_by_addr_port(circ->cpath->prev->addr,
// circ->cpath->prev->port);
// else /* not open */
/* for rend circs, circ->cpath->prev is not the last router in the
* circuit, it's the magical extra bob hop. so just check the nickname
* of the one we meant to finish at.
*/
exitrouter = router_get_by_nickname(circ->build_state->chosen_exit);
if(!exitrouter) {
log_fn(LOG_INFO,"Skipping broken circ (exit router vanished)");
return 0; /* this circuit is screwed and doesn't know it yet */
}
if(purpose == CIRCUIT_PURPOSE_C_GENERAL) {
if(connection_ap_can_use_exit(conn, exitrouter) == ADDR_POLICY_REJECTED) {
/* can't exit from this router */
return 0;
}
} else { /* not general */
if(rend_cmp_service_ids(conn->rend_query, circ->rend_query)) {
/* this circ is not for this conn */
return 0;
}
}
}
return 0;
}
/* Return 1 iff circuit 'a' is better than circuit 'b' for purpose. Used by
* circuit_get_best
*/
static int circuit_is_better(circuit_t *a, circuit_t *b, uint8_t purpose)
{
switch(purpose) {
case CIRCUIT_PURPOSE_C_GENERAL:
/* if it's used but less dirty it's best;
* else if it's more recently created it's best
*/
if(b->timestamp_dirty) {
if(a->timestamp_dirty &&
a->timestamp_dirty > b->timestamp_dirty)
return 1;
} else {
if(a->timestamp_dirty ||
a->timestamp_created > b->timestamp_created)
return 1;
}
break;
case CIRCUIT_PURPOSE_C_INTRODUCING:
/* more recently created is best */
if(a->timestamp_created > b->timestamp_created)
return 1;
break;
case CIRCUIT_PURPOSE_C_REND_JOINED:
/* the closer it is to rend_joined the better it is */
if(a->purpose > b->purpose)
return 1;
break;
}
return 0;
}
/* Find the best circ that conn can use, preferably one which is
* dirty. Circ must not be too old.
* If !conn, return newest.
@ -268,7 +367,6 @@ circuit_t *circuit_get_by_conn(connection_t *conn) {
circuit_t *circuit_get_best(connection_t *conn,
int must_be_open, uint8_t purpose) {
circuit_t *circ, *best=NULL;
routerinfo_t *exitrouter;
time_t now = time(NULL);
assert(purpose == CIRCUIT_PURPOSE_C_GENERAL ||
@ -276,93 +374,14 @@ circuit_t *circuit_get_best(connection_t *conn,
purpose == CIRCUIT_PURPOSE_C_REND_JOINED);
for (circ=global_circuitlist;circ;circ = circ->next) {
if (!circ->cpath)
continue; /* this circ doesn't start at us */
if (must_be_open && (circ->state != CIRCUIT_STATE_OPEN || !circ->n_conn))
continue; /* ignore non-open circs */
if (circ->marked_for_close)
if (!circuit_is_acceptable(circ,conn,must_be_open,purpose,now))
continue;
/* if this circ isn't our purpose, skip. */
if(purpose == CIRCUIT_PURPOSE_C_REND_JOINED) {
if(must_be_open && purpose != circ->purpose)
continue;
if(circ->purpose != CIRCUIT_PURPOSE_C_ESTABLISH_REND &&
circ->purpose != CIRCUIT_PURPOSE_C_REND_READY &&
circ->purpose != CIRCUIT_PURPOSE_C_REND_JOINED)
continue;
} else {
if(purpose != circ->purpose)
continue;
}
if(purpose == CIRCUIT_PURPOSE_C_GENERAL)
if(circ->timestamp_dirty &&
circ->timestamp_dirty+options.NewCircuitPeriod < now)
continue; /* too old */
if(conn) {
/* decide if this circ is suitable for this conn */
// if(circ->state == CIRCUIT_STATE_OPEN && circ->n_conn) /* open */
// exitrouter = router_get_by_addr_port(circ->cpath->prev->addr,
// circ->cpath->prev->port);
// else /* not open */
/* for rend circs, circ->cpath->prev is not the last router in the
* circuit, it's the magical extra bob hop. so just check the nickname
* of the one we meant to finish at.
*/
exitrouter = router_get_by_nickname(circ->build_state->chosen_exit);
if(!exitrouter) {
log_fn(LOG_INFO,"Skipping broken circ (exit router vanished)");
continue; /* this circuit is screwed and doesn't know it yet */
}
if(purpose == CIRCUIT_PURPOSE_C_GENERAL) {
if(connection_ap_can_use_exit(conn, exitrouter) == ADDR_POLICY_REJECTED) {
/* can't exit from this router */
continue;
}
} else { /* not general */
if(rend_cmp_service_ids(conn->rend_query, circ->rend_query)) {
/* this circ is not for this conn */
continue;
}
}
}
/* now this is an acceptable circ to hand back. but that doesn't
* mean it's the *best* circ to hand back. try to decide.
*/
if(!best)
if(!best || circuit_is_better(circ,best,purpose))
best = circ;
switch(purpose) {
case CIRCUIT_PURPOSE_C_GENERAL:
/* if it's used but less dirty it's best;
* else if it's more recently created it's best
*/
if(best->timestamp_dirty) {
if(circ->timestamp_dirty &&
circ->timestamp_dirty > best->timestamp_dirty)
best = circ;
} else {
if(circ->timestamp_dirty ||
circ->timestamp_created > best->timestamp_created)
best = circ;
}
break;
case CIRCUIT_PURPOSE_C_INTRODUCING:
/* more recently created is best */
if(circ->timestamp_created > best->timestamp_created)
best = circ;
break;
case CIRCUIT_PURPOSE_C_REND_JOINED:
/* the closer it is to rend_joined the better it is */
if(circ->purpose > best->purpose)
best = circ;
break;
}
}
return best;