commit 98af25e0137f283569aee3537a0ef19cda403426 Author: George Kadianakis <desnacked@riseup.net> Date: Wed Feb 13 16:17:01 2019 +0200 Remove start_usec/range_usec and make equivalent fields for distributions. --- src/core/or/circuitpadding.c | 18 +++++++----------- src/core/or/circuitpadding.h | 25 +++++++------------------ src/test/test_circuitpadding.c | 24 ++++++++++++------------ 3 files changed, 26 insertions(+), 41 deletions(-) diff --git a/src/core/or/circuitpadding.c b/src/core/or/circuitpadding.c index 0dadc5213..a9c5796ca 100644 --- a/src/core/or/circuitpadding.c +++ b/src/core/or/circuitpadding.c @@ -399,17 +399,17 @@ 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 start_usec) + circpad_delay_t min_delay) { 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->range_usec); + val = MIN(val, state->dist_max_usec); - /* This addition is exact: val is at most 2**32-1, start_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 += start_usec; + val += min_delay; /* Clamp the distribution at infinite delay val */ return (circpad_delay_t)MIN(tor_llround(val), CIRCPAD_DELAY_INFINITE); @@ -429,7 +429,6 @@ circpad_machine_sample_delay(circpad_machine_state_t *mi) const circpad_hist_token_t *histogram = NULL; circpad_hist_index_t curr_bin = 0; circpad_delay_t bin_start, bin_end; - circpad_delay_t start_usec; /* These three must all be larger than circpad_hist_token_t, because * we sum several circpad_hist_token_t values across the histogram */ uint64_t curr_weight = 0; @@ -438,14 +437,11 @@ circpad_machine_sample_delay(circpad_machine_state_t *mi) tor_assert(state); - if (state->use_rtt_estimate) - start_usec = mi->rtt_estimate_usec+state->start_usec; - else - start_usec = state->start_usec; - if (state->iat_dist.type != CIRCPAD_DIST_NONE) { /* Sample from a fixed IAT distribution and return */ - return circpad_distribution_sample_iat_delay(state, start_usec); + 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); } 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 57bd37981..918a7d0dd 100644 --- a/src/core/or/circuitpadding.h +++ b/src/core/or/circuitpadding.h @@ -297,24 +297,6 @@ typedef struct circpad_state_t { * refilling the histogram. */ uint32_t histogram_total_tokens; - /** Minimum padding delay of this state in microseconds. - * - * If histograms are used, this is the left (and right) bound of the first - * bin (since it has zero width). - * - * If a delay probability distribution is used, this represents the minimum - * delay we can sample from the distribution. - */ - circpad_delay_t start_usec; - - /** If histograms are used, this is the width of the whole histogram in - * microseconds, and it's used to calculate individual bin width. - * - * If a delay probability distribution is used, this is used as the max - * delay we can sample from the distribution. - */ - circpad_delay_t range_usec; - /** * Represents a delay probability distribution (aka IAT distribution). It's a * parametrized way of encoding inter-packet delay information in @@ -327,6 +309,13 @@ 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; /** * 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 12a07fa95..63d8f8e09 100644 --- a/src/test/test_circuitpadding.c +++ b/src/test/test_circuitpadding.c @@ -2067,48 +2067,48 @@ 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->start_usec = min; - zero_st->range_usec = max; + zero_st->dist_min_usec = min; + zero_st->dist_max_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->start_usec = min; - first_st->range_usec = max; + first_st->dist_min_usec = min; + first_st->dist_max_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->start_usec = min; - second_st->range_usec = max; + second_st->dist_min_usec = min; + second_st->dist_max_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->start_usec = min; - third_st->range_usec = max; + third_st->dist_min_usec = min; + third_st->dist_max_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->start_usec = min; - fourth_st->range_usec = max; + fourth_st->dist_min_usec = min; + fourth_st->dist_max_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->start_usec = min; - fifth_st->range_usec = max; + fifth_st->dist_min_usec = min; + fifth_st->dist_max_usec = max; } /** Simple test that the padding delays sampled from a uniform distribution