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Do away with the complexity of the network liveness detection.

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We really should ignore any timeouts that have *no* network activity for their
entire measured lifetime, now that we have the 95th percentile measurement
changes. Usually this is up to a minute, even on fast connections.
This commit is contained in:
Mike Perry 2010-09-29 08:55:11 -07:00
parent 0744a175af
commit 11910cf5b3
3 changed files with 28 additions and 101 deletions
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71
src/or/circuitbuild.c
View File

@ -306,6 +306,7 @@ circuit_build_times_init(circuit_build_times_t *cbt)
control_event_buildtimeout_set(cbt, BUILDTIMEOUT_SET_EVENT_RESET);
}
#if 0
/**
* Rewind our build time history by n positions.
*/
@ -332,6 +333,7 @@ circuit_build_times_rewind_history(circuit_build_times_t *cbt, int n)
"Rewound history by %d places. Current index: %d. "
"Total: %d", n, cbt->build_times_idx, cbt->total_build_times);
}
#endif
/**
* Add a new build time value <b>time</b> to the set of build times. Time
@ -941,8 +943,16 @@ circuit_build_times_needs_circuits_now(circuit_build_times_t *cbt)
void
circuit_build_times_network_is_live(circuit_build_times_t *cbt)
{
cbt->liveness.network_last_live = approx_time();
cbt->liveness.nonlive_discarded = 0;
time_t now = approx_time();
if (cbt->liveness.nonlive_timeouts > 0) {
log_notice(LD_CIRC,
"Tor now sees network activity. Restoring circuit build "
"timeout recording. Network was down for %ld seconds "
"during %d circuit attempts.",
(long int)now - cbt->liveness.network_last_live,
cbt->liveness.nonlive_timeouts);
}
cbt->liveness.network_last_live = now;
cbt->liveness.nonlive_timeouts = 0;
}
@ -1002,9 +1012,16 @@ circuit_build_times_network_close(circuit_build_times_t *cbt,
now_buf);
}
cbt->liveness.nonlive_timeouts++;
log_info(LD_CIRC,
if (cbt->liveness.nonlive_timeouts == 1) {
log_notice(LD_CIRC,
"Tor has not observed any network activity for the past %ld "
"seconds. Disabling circuit build timeout code.",
(long int)now - cbt->liveness.network_last_live);
} else {
log_info(LD_CIRC,
"Got non-live timeout. Current count is: %d",
cbt->liveness.nonlive_timeouts);
}
}
}
@ -1018,54 +1035,8 @@ circuit_build_times_network_close(circuit_build_times_t *cbt,
int
circuit_build_times_network_check_live(circuit_build_times_t *cbt)
{
time_t now = approx_time();
if (cbt->liveness.nonlive_timeouts >= CBT_NETWORK_NONLIVE_DISCARD_COUNT) {
if (!cbt->liveness.nonlive_discarded) {
cbt->liveness.nonlive_discarded = 1;
log_notice(LD_CIRC, "Network is no longer live (too many recent "
"circuit timeouts). Dead for %ld seconds.",
(long int)(now - cbt->liveness.network_last_live));
/* Only discard NETWORK_NONLIVE_TIMEOUT_COUNT-1 because we stopped
* counting after that */
circuit_build_times_rewind_history(cbt,
CBT_NETWORK_NONLIVE_TIMEOUT_COUNT-1);
control_event_buildtimeout_set(cbt, BUILDTIMEOUT_SET_EVENT_DISCARD);
}
if (cbt->liveness.nonlive_timeouts > 0) {
return 0;
} else if (cbt->liveness.nonlive_timeouts >=
CBT_NETWORK_NONLIVE_TIMEOUT_COUNT) {
if (cbt->liveness.suspended_timeout <= 0) {
cbt->liveness.suspended_timeout = cbt->timeout_ms;
cbt->liveness.suspended_close_timeout = cbt->close_ms;
if (cbt->timeout_ms < circuit_build_times_get_initial_timeout())
cbt->timeout_ms = circuit_build_times_get_initial_timeout();
else
cbt->timeout_ms *= 2;
if (cbt->close_ms < circuit_build_times_get_initial_timeout())
cbt->close_ms = circuit_build_times_get_initial_timeout();
else
cbt->close_ms *= 2;
log_notice(LD_CIRC,
"Network is flaky. No activity for %ld seconds. "
"Temporarily raising timeout to %lds.",
(long int)(now - cbt->liveness.network_last_live),
tor_lround(cbt->timeout_ms/1000));
control_event_buildtimeout_set(cbt, BUILDTIMEOUT_SET_EVENT_SUSPENDED);
}
return 0;
} else if (cbt->liveness.suspended_timeout > 0) {
log_notice(LD_CIRC,
"Network activity has resumed. "
"Resuming circuit timeout calculations.");
cbt->timeout_ms = cbt->liveness.suspended_timeout;
cbt->close_ms = cbt->liveness.suspended_close_timeout;
cbt->liveness.suspended_timeout = 0;
cbt->liveness.suspended_close_timeout = 0;
control_event_buildtimeout_set(cbt, BUILDTIMEOUT_SET_EVENT_RESUME);
}
return 1;

32
src/or/or.h
View File

@ -2961,26 +2961,6 @@ typedef uint32_t build_time_t;
/** Save state every 10 circuits */
#define CBT_SAVE_STATE_EVERY 10
/* Circuit Build Timeout network liveness constants */
/**
* Have we received a cell in the last N circ attempts?
*
* This tells us when to temporarily switch back to
* BUILD_TIMEOUT_INITIAL_VALUE until we start getting cells,
* at which point we switch back to computing the timeout from
* our saved history.
*/
#define CBT_NETWORK_NONLIVE_TIMEOUT_COUNT 3
/**
* This tells us when to toss out the last streak of N timeouts.
*
* If instead we start getting cells, we switch back to computing the timeout
* from our saved history.
*/
#define CBT_NETWORK_NONLIVE_DISCARD_COUNT (CBT_NETWORK_NONLIVE_TIMEOUT_COUNT*2)
/* Circuit build times consensus parameters */
/**
@ -3021,9 +3001,7 @@ double circuit_build_times_quantile_cutoff(void);
#define CBT_DEFAULT_TIMEOUT_INITIAL_VALUE (60*1000)
int32_t circuit_build_times_initial_timeout(void);
#if CBT_DEFAULT_MAX_RECENT_TIMEOUT_COUNT < 1 || \
CBT_NETWORK_NONLIVE_DISCARD_COUNT < 1 || \
CBT_NETWORK_NONLIVE_TIMEOUT_COUNT < 1
#if CBT_DEFAULT_MAX_RECENT_TIMEOUT_COUNT < 1
#error "RECENT_CIRCUITS is set too low."
#endif
@ -3033,8 +3011,6 @@ typedef struct {
time_t network_last_live;
/** If the network is not live, how many timeouts has this caused? */
int nonlive_timeouts;
/** If the network is not live, have we yet discarded our history? */
int nonlive_discarded;
/** Circular array of circuits that have made it to the first hop. Slot is
* 1 if circuit timed out, 0 if circuit succeeded */
int8_t *timeouts_after_firsthop;
@ -3042,12 +3018,6 @@ typedef struct {
int num_recent_circs;
/** Index into circular array. */
int after_firsthop_idx;
/** Timeout gathering is suspended if non-zero. The old timeout value
* is stored here in that case. */
double suspended_timeout;
/** Timeout gathering is suspended if non-zero. The old close value
* is stored here in that case. */
double suspended_close_timeout;
} network_liveness_t;
/** Structure for circuit build times history */

26
src/test/test.c
View File

@ -499,28 +499,14 @@ test_circuit_timeout(void)
build_times_idx = estimate.build_times_idx;
total_build_times = estimate.total_build_times;
for (i = 0; i < CBT_NETWORK_NONLIVE_TIMEOUT_COUNT; i++) {
test_assert(circuit_build_times_network_check_live(&estimate));
test_assert(circuit_build_times_network_check_live(&final));
circuit_build_times_count_close(&estimate, 0,
(time_t)(approx_time()-estimate.close_ms/1000.0-1));
circuit_build_times_count_close(&final, 0,
(time_t)(approx_time()-final.close_ms/1000.0-1));
}
test_assert(circuit_build_times_network_check_live(&estimate));
test_assert(circuit_build_times_network_check_live(&final));
test_assert(!circuit_build_times_network_check_live(&estimate));
test_assert(!circuit_build_times_network_check_live(&final));
for ( ; i < CBT_NETWORK_NONLIVE_DISCARD_COUNT; i++) {
circuit_build_times_count_close(&estimate, 0,
(time_t)(approx_time()-estimate.close_ms/1000.0-1));
if (i < CBT_NETWORK_NONLIVE_DISCARD_COUNT-1) {
circuit_build_times_count_close(&final, 0,
(time_t)(approx_time()-final.close_ms/1000.0-1));
}
}
circuit_build_times_count_close(&estimate, 0,
(time_t)(approx_time()-estimate.close_ms/1000.0-1));
circuit_build_times_count_close(&final, 0,
(time_t)(approx_time()-final.close_ms/1000.0-1));
test_assert(!circuit_build_times_network_check_live(&estimate));
test_assert(!circuit_build_times_network_check_live(&final));