commit 331a067ae3ce778037650d5283504350979e50ee Author: George Kadianakis desnacked@riseup.net Date: Mon Feb 25 13:46:58 2019 +0200
Fix dist_min_usec documentation and naming. --- src/core/or/circuitpadding.c | 13 +++++++------ src/core/or/circuitpadding.h | 15 +++++++++------ src/test/test_circuitpadding.c | 24 ++++++++++++------------ 3 files changed, 28 insertions(+), 24 deletions(-)
diff --git a/src/core/or/circuitpadding.c b/src/core/or/circuitpadding.c index 09dda6da3..7e76cd7ad 100644 --- a/src/core/or/circuitpadding.c +++ b/src/core/or/circuitpadding.c @@ -380,17 +380,17 @@ circpad_choose_state_length(circpad_machine_state_t *mi) */ static circpad_delay_t circpad_distribution_sample_iat_delay(const circpad_state_t *state, - circpad_delay_t min_delay) + circpad_delay_t delay_shift) { 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. */ val = MAX(0, val); - val = MIN(val, state->dist_max_usec); + 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. */ - val += min_delay; + val += delay_shift;
/* Clamp the distribution at infinite delay val */ return (circpad_delay_t)MIN(tor_llround(val), CIRCPAD_DELAY_INFINITE); @@ -420,9 +420,10 @@ circpad_machine_sample_delay(circpad_machine_state_t *mi)
if (state->iat_dist.type != CIRCPAD_DIST_NONE) { /* Sample from a fixed IAT distribution and return */ - circpad_delay_t min_iat_delay = state->use_rtt_estimate ? - mi->rtt_estimate_usec + state->dist_min_usec : state->dist_min_usec; - return circpad_distribution_sample_iat_delay(state, min_iat_delay); + circpad_delay_t iat_delay_shift = state->use_rtt_estimate ? + mi->rtt_estimate_usec + state->dist_added_shift_usec : + state->dist_added_shift_usec; + return circpad_distribution_sample_iat_delay(state, iat_delay_shift); } else if (state->token_removal != CIRCPAD_TOKEN_REMOVAL_NONE) { /* We have a mutable histogram. Do basic sanity check and apply: */ if (BUG(!mi->histogram) || diff --git a/src/core/or/circuitpadding.h b/src/core/or/circuitpadding.h index d11358a15..4e6454b4a 100644 --- a/src/core/or/circuitpadding.h +++ b/src/core/or/circuitpadding.h @@ -309,13 +309,16 @@ typedef struct circpad_state_t { * results of sampling from this distribution (range_sec is used as a max). */ circpad_distribution_t iat_dist; - /* If a delay probability distribution is used, this represents the minimum - * delay we can sample from the distribution. */ - circpad_delay_t dist_min_usec; /* If a delay probability distribution is used, this is used as the max - * delay we can sample from the distribution. - */ - circpad_delay_t dist_max_usec; + * value we can sample from the distribution. However, RTT measurements and + * dist_added_shift gets applied on top of this value to derive the final + * padding delay. */ + circpad_delay_t dist_max_sample_usec; + /* If a delay probability distribution is used and this is set, we will add + * this value on top of the value sampled from the IAT distribution to + * derive the final padding delay (We also add the RTT measurement if it's + * enabled.). */ + circpad_delay_t dist_added_shift_usec;
/** * The length dist is a parameterized way of encoding how long this diff --git a/src/test/test_circuitpadding.c b/src/test/test_circuitpadding.c index 599b7fb24..3570b179b 100644 --- a/src/test/test_circuitpadding.c +++ b/src/test/test_circuitpadding.c @@ -2098,48 +2098,48 @@ helper_circpad_circ_distribution_machine_setup(int min, int max) zero_st->iat_dist.type = CIRCPAD_DIST_UNIFORM; zero_st->iat_dist.param1 = min; zero_st->iat_dist.param2 = max; - zero_st->dist_min_usec = min; - zero_st->dist_max_usec = max; + zero_st->dist_added_shift_usec = min; + zero_st->dist_max_sample_usec = 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; - first_st->dist_min_usec = min; - first_st->dist_max_usec = max; + 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; - second_st->dist_min_usec = min; - second_st->dist_max_usec = max; + 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; - third_st->dist_min_usec = min; - third_st->dist_max_usec = max; + 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; - fourth_st->dist_min_usec = min; - fourth_st->dist_max_usec = max; + 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; - fifth_st->dist_min_usec = min; - fifth_st->dist_max_usec = max; + 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