[tor-commits] [tor/master] Fix test prob distr parameters that caused warnings.
nickm at torproject.org
nickm at torproject.org
Wed Mar 13 14:37:42 UTC 2019
commit a71999462b8d185c70169c4cba3efde6e55393ce
Author: George Kadianakis <desnacked at riseup.net>
Date: Mon Feb 25 14:59:28 2019 +0200
Fix test prob distr parameters that caused warnings.
They were causing the following warnings in circuitpadding/circuitpadding_sample_distribution:
src/lib/math/prob_distr.c:1311:17: runtime error: division by zero
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior src/lib/math/prob_distr.c:1311:17 in
src/lib/math/prob_distr.c:1219:49: runtime error: division by zero
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior src/lib/math/prob_distr.c:1219:49 in
because the distributions were called with erroneous parameters (e.g. geometric
distribution with p=0).
We now defined these test probability distributions with more realistic
parameters.
As far as the circuitpadding_sample_distribution() test is concerned, it
doesn't matter if the distributions return values outside of [0,10] since we
already restrict the values into that interval using min=0 and max=10 (and RTT
estimate is disabled).
---
src/core/or/circuitpadding.c | 7 +++++--
src/core/or/circuitpadding.h | 11 ++++++++++-
src/test/test_circuitpadding.c | 30 ++++++++++++++++--------------
3 files changed, 31 insertions(+), 17 deletions(-)
diff --git a/src/core/or/circuitpadding.c b/src/core/or/circuitpadding.c
index b7e4b5684..9e8790277 100644
--- a/src/core/or/circuitpadding.c
+++ b/src/core/or/circuitpadding.c
@@ -389,11 +389,14 @@ circpad_distribution_sample_iat_delay(const circpad_state_t *state,
double val = circpad_distribution_sample(state->iat_dist);
/* These comparisons are safe, because the output is in the range
* [0, 2**32), and double has a precision of 53 bits. */
+ /* We want a positive sample value */
val = MAX(0, val);
+ /* Respect the maximum sample setting */
val = MIN(val, state->dist_max_sample_usec);
- /* This addition is exact: val is at most 2**32-1, min_delay
- * is at most 2**32-1, and doubles have a precision of 53 bits. */
+ /* Now apply the shift:
+ * This addition is exact: val is at most 2**32-1, delay_shift is at most
+ * 2**32-1, and doubles have a precision of 53 bits. */
val += delay_shift;
/* Clamp the distribution at infinite delay val */
diff --git a/src/core/or/circuitpadding.h b/src/core/or/circuitpadding.h
index 74f9f35c9..fefdf2ba9 100644
--- a/src/core/or/circuitpadding.h
+++ b/src/core/or/circuitpadding.h
@@ -198,14 +198,23 @@ typedef enum {
* These can be used instead of histograms for the inter-packet
* timing distribution, or to specify a distribution on the number
* of cells that can be sent while in a specific state of the state
- * machine. */
+ * machine.
+ *
+ * Each distribution takes up to two parameters which are described below. */
typedef enum {
+ /* No probability distribution is used */
CIRCPAD_DIST_NONE = 0,
+ /* Uniform distribution: param1 is lower bound and param2 is upper bound */
CIRCPAD_DIST_UNIFORM = 1,
+ /* Logistic distribution: param1 is Mu, param2 is sigma. */
CIRCPAD_DIST_LOGISTIC = 2,
+ /* Log-logistic distribution: param1 is Alpha, param2 is 1.0/Beta */
CIRCPAD_DIST_LOG_LOGISTIC = 3,
+ /* Geometric distribution: param1 is 'p' (success probability) */
CIRCPAD_DIST_GEOMETRIC = 4,
+ /* Weibull distribution: param1 is k, param2 is Lambda */
CIRCPAD_DIST_WEIBULL = 5,
+ /* Generalized Pareto distribution: param1 is sigma, param2 is xi */
CIRCPAD_DIST_PARETO = 6
} circpad_distribution_type_t;
diff --git a/src/test/test_circuitpadding.c b/src/test/test_circuitpadding.c
index 3570b179b..d349a4d3c 100644
--- a/src/test/test_circuitpadding.c
+++ b/src/test/test_circuitpadding.c
@@ -2096,6 +2096,7 @@ helper_circpad_circ_distribution_machine_setup(int min, int max)
circpad_state_t *zero_st = &circ_client_machine.states[0];
zero_st->next_state[CIRCPAD_EVENT_NONPADDING_RECV] = 1;
zero_st->iat_dist.type = CIRCPAD_DIST_UNIFORM;
+ /* param2 is upper bound, param1 is lower */
zero_st->iat_dist.param1 = min;
zero_st->iat_dist.param2 = max;
zero_st->dist_added_shift_usec = min;
@@ -2104,48 +2105,50 @@ helper_circpad_circ_distribution_machine_setup(int min, int max)
circpad_state_t *first_st = &circ_client_machine.states[1];
first_st->next_state[CIRCPAD_EVENT_NONPADDING_RECV] = 2;
first_st->iat_dist.type = CIRCPAD_DIST_LOGISTIC;
- first_st->iat_dist.param1 = min;
- first_st->iat_dist.param2 = max;
+ /* param1 is Mu, param2 is sigma. */
+ first_st->iat_dist.param1 = 9;
+ first_st->iat_dist.param2 = 3;
first_st->dist_added_shift_usec = min;
first_st->dist_max_sample_usec = max;
circpad_state_t *second_st = &circ_client_machine.states[2];
second_st->next_state[CIRCPAD_EVENT_NONPADDING_RECV] = 3;
second_st->iat_dist.type = CIRCPAD_DIST_LOG_LOGISTIC;
- second_st->iat_dist.param1 = min;
- second_st->iat_dist.param2 = max;
+ /* param1 is Alpha, param2 is 1.0/Beta */
+ second_st->iat_dist.param1 = 1;
+ second_st->iat_dist.param2 = 0.5;
second_st->dist_added_shift_usec = min;
second_st->dist_max_sample_usec = max;
circpad_state_t *third_st = &circ_client_machine.states[3];
third_st->next_state[CIRCPAD_EVENT_NONPADDING_RECV] = 4;
third_st->iat_dist.type = CIRCPAD_DIST_GEOMETRIC;
- third_st->iat_dist.param1 = min;
- third_st->iat_dist.param2 = max;
+ /* param1 is 'p' (success probability) */
+ third_st->iat_dist.param1 = 0.2;
third_st->dist_added_shift_usec = min;
third_st->dist_max_sample_usec = max;
circpad_state_t *fourth_st = &circ_client_machine.states[4];
fourth_st->next_state[CIRCPAD_EVENT_NONPADDING_RECV] = 5;
fourth_st->iat_dist.type = CIRCPAD_DIST_WEIBULL;
- fourth_st->iat_dist.param1 = min;
- fourth_st->iat_dist.param2 = max;
+ /* param1 is k, param2 is Lambda */
+ fourth_st->iat_dist.param1 = 1.5;
+ fourth_st->iat_dist.param2 = 1;
fourth_st->dist_added_shift_usec = min;
fourth_st->dist_max_sample_usec = max;
circpad_state_t *fifth_st = &circ_client_machine.states[5];
fifth_st->next_state[CIRCPAD_EVENT_NONPADDING_RECV] = 6;
fifth_st->iat_dist.type = CIRCPAD_DIST_PARETO;
- fifth_st->iat_dist.param1 = min;
- fifth_st->iat_dist.param2 = max;
+ /* param1 is sigma, param2 is xi */
+ fifth_st->iat_dist.param1 = 1;
+ fifth_st->iat_dist.param2 = 5;
fifth_st->dist_added_shift_usec = min;
fifth_st->dist_max_sample_usec = max;
}
/** Simple test that the padding delays sampled from a uniform distribution
* actually faill within the uniform distribution range. */
-/* TODO: Upgrade this test so that each state tests a different prob
- * distribution */
static void
test_circuitpadding_sample_distribution(void *arg)
{
@@ -2159,8 +2162,7 @@ test_circuitpadding_sample_distribution(void *arg)
MOCK(circpad_machine_schedule_padding,
circpad_machine_schedule_padding_mock);
- /* Initialize a machine with multiple probability distributions that should
- * return values between 0 and 5 */
+ /* Initialize a machine with multiple probability distributions */
circpad_machines_init();
helper_circpad_circ_distribution_machine_setup(0, 10);
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