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Merge remote-tracking branch 'tor-github/pr/705'

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This commit is contained in:
Nick Mathewson 2019-03-13 09:36:47 -04:00
commit 58fd864a85
4 changed files with 326 additions and 179 deletions
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6
changes/bug29298 Normal file
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@ -0,0 +1,6 @@
o Minor features (circuit padding):
- Allow the padding machine designer to pick the edges of their histogram
instead of trying to compute them automatically using an exponential
formula. Resolves some undefined behavior in the case of small histograms
and allows greater flexibility on machine design. Closes ticket 29298;
bugfix on 0.4.0.1-alpha.

258
src/core/or/circuitpadding.c
View File

@ -224,25 +224,20 @@ circpad_machine_current_state(const circpad_machine_state_t *mi)
} }
/** /**
* Calculate the lower bound of a histogram bin. The upper bound * Get the lower bound of a histogram bin.
* is obtained by calling this function with bin+1, and subtracting 1.
* *
* The 0th bin has a special value -- it only represents start_usec. * You can obtain the upper bound using histogram_get_bin_upper_bound().
* This is so we can specify a probability on 0-delay values.
* *
* After bin 0, bins are exponentially spaced, so that each subsequent * This function can also be called with 'bin' set to a value equal or greater
* bin is twice as large as the previous. This is done so that higher * than histogram_len in which case the infinity bin is chosen and
* time resolution is given to lower time values. * CIRCPAD_DELAY_INFINITE is returned.
*
* The infinity bin is a the last bin in the array (histogram_len-1).
* It has a usec value of CIRCPAD_DELAY_INFINITE (UINT32_MAX).
*/ */
STATIC circpad_delay_t STATIC circpad_delay_t
circpad_histogram_bin_to_usec(const circpad_machine_state_t *mi, circpad_histogram_bin_to_usec(const circpad_machine_state_t *mi,
circpad_hist_index_t bin) circpad_hist_index_t bin)
{ {
const circpad_state_t *state = circpad_machine_current_state(mi); const circpad_state_t *state = circpad_machine_current_state(mi);
circpad_delay_t start_usec; circpad_delay_t rtt_add_usec = 0;
/* Our state should have been checked to be non-null by the caller /* Our state should have been checked to be non-null by the caller
* (circpad_machine_remove_token()) */ * (circpad_machine_remove_token()) */
@ -250,27 +245,29 @@ circpad_histogram_bin_to_usec(const circpad_machine_state_t *mi,
return CIRCPAD_DELAY_INFINITE; return CIRCPAD_DELAY_INFINITE;
} }
if (state->use_rtt_estimate) /* The infinity bin has an upper bound of infinity, so make sure we return
start_usec = mi->rtt_estimate_usec+state->start_usec; * that if they ask for it. */
else if (bin > CIRCPAD_INFINITY_BIN(mi)) {
start_usec = state->start_usec;
if (bin >= CIRCPAD_INFINITY_BIN(state))
return CIRCPAD_DELAY_INFINITE; return CIRCPAD_DELAY_INFINITE;
}
if (bin == 0) /* If we are using an RTT estimate, consider it as well. */
return start_usec; if (state->use_rtt_estimate) {
rtt_add_usec = mi->rtt_estimate_usec;
}
if (bin == 1) return state->histogram_edges[bin] + rtt_add_usec;
return start_usec+1; }
/* The bin widths double every index, so that we can have more resolution /**
* for lower time values in the histogram. */ * Like circpad_histogram_bin_to_usec() but return the upper bound of bin.
const circpad_time_t bin_width_exponent = * (The upper bound is included in the bin.)
1 << (CIRCPAD_INFINITY_BIN(state) - bin); */
return (circpad_delay_t)MIN(start_usec + STATIC circpad_delay_t
state->range_usec/bin_width_exponent, histogram_get_bin_upper_bound(const circpad_machine_state_t *mi,
CIRCPAD_DELAY_INFINITE); circpad_hist_index_t bin)
{
return circpad_histogram_bin_to_usec(mi, bin+1) - 1;
} }
/** Return the midpoint of the histogram bin <b>bin_index</b>. */ /** Return the midpoint of the histogram bin <b>bin_index</b>. */
@ -279,8 +276,7 @@ circpad_get_histogram_bin_midpoint(const circpad_machine_state_t *mi,
int bin_index) int bin_index)
{ {
circpad_delay_t left_bound = circpad_histogram_bin_to_usec(mi, bin_index); circpad_delay_t left_bound = circpad_histogram_bin_to_usec(mi, bin_index);
circpad_delay_t right_bound = circpad_delay_t right_bound = histogram_get_bin_upper_bound(mi, bin_index);
circpad_histogram_bin_to_usec(mi, bin_index+1)-1;
return left_bound + (right_bound - left_bound)/2; return left_bound + (right_bound - left_bound)/2;
} }
@ -289,19 +285,17 @@ circpad_get_histogram_bin_midpoint(const circpad_machine_state_t *mi,
* Return the bin that contains the usec argument. * Return the bin that contains the usec argument.
* "Contains" is defined as us in [lower, upper). * "Contains" is defined as us in [lower, upper).
* *
* This function will never return the infinity bin (histogram_len-1), * This function will never return the infinity bin (histogram_len-1), in order
* in order to simplify the rest of the code. * to simplify the rest of the code, so if a usec is provided that falls above
* * the highest non-infinity bin, that bin index will be returned.
* This means that technically the last bin (histogram_len-2)
* has range [start_usec+range_usec, CIRCPAD_DELAY_INFINITE].
*/ */
STATIC circpad_hist_index_t STATIC circpad_hist_index_t
circpad_histogram_usec_to_bin(const circpad_machine_state_t *mi, circpad_histogram_usec_to_bin(const circpad_machine_state_t *mi,
circpad_delay_t usec) circpad_delay_t usec)
{ {
const circpad_state_t *state = circpad_machine_current_state(mi); const circpad_state_t *state = circpad_machine_current_state(mi);
circpad_delay_t start_usec; circpad_delay_t rtt_add_usec = 0;
int32_t bin; /* Larger than return type to properly clamp overflow */ circpad_hist_index_t bin;
/* Our state should have been checked to be non-null by the caller /* Our state should have been checked to be non-null by the caller
* (circpad_machine_remove_token()) */ * (circpad_machine_remove_token()) */
@ -309,34 +303,25 @@ circpad_histogram_usec_to_bin(const circpad_machine_state_t *mi,
return 0; return 0;
} }
if (state->use_rtt_estimate) /* If we are using an RTT estimate, consider it as well. */
start_usec = mi->rtt_estimate_usec+state->start_usec; if (state->use_rtt_estimate) {
else rtt_add_usec = mi->rtt_estimate_usec;
start_usec = state->start_usec; }
/* The first bin (#0) has zero width and starts (and ends) at start_usec. */ /* Walk through the bins and check the upper bound of each bin, if 'usec' is
if (usec <= start_usec) * less-or-equal to that, return that bin. If rtt_estimate is enabled then
return 0; * add that to the upper bound of each bin.
*
* We don't want to return the infinity bin here, so don't go there. */
for (bin = 0 ; bin < CIRCPAD_INFINITY_BIN(state) ; bin++) {
if (usec <= histogram_get_bin_upper_bound(mi, bin) + rtt_add_usec) {
return bin;
}
}
if (usec == start_usec+1) /* We don't want to return the infinity bin here, so if we still didn't find
return 1; * the right bin, return the highest non-infinity bin */
return CIRCPAD_INFINITY_BIN(state)-1;
const circpad_time_t histogram_range_usec = state->range_usec;
/* We need to find the bin corresponding to our position in the range.
* Since bins are exponentially spaced in powers of two, we need to
* take the log2 of our position in histogram_range_usec. However,
* since tor_log2() returns the floor(log2(u64)), we have to adjust
* it to behave like ceil(log2(u64)). This is verified in our tests
* to properly invert the operation done in
* circpad_histogram_bin_to_usec(). */
bin = CIRCPAD_INFINITY_BIN(state) -
tor_log2(2*histogram_range_usec/(usec-start_usec+1));
/* Clamp the return value to account for timevals before the start
* of bin 0, or after the last bin. Don't return the infinity bin
* index. */
bin = MIN(MAX(bin, 1), CIRCPAD_INFINITY_BIN(state)-1);
return bin;
} }
/** /**
@ -398,20 +383,22 @@ circpad_choose_state_length(circpad_machine_state_t *mi)
/** /**
* Sample a value from our iat_dist, and clamp it safely * Sample a value from our iat_dist, and clamp it safely
* to circpad_delay_t. * to circpad_delay_t.
*
* Before returning, add <b>delay_shift</b> (can be zero) to the sampled value.
*/ */
static circpad_delay_t static circpad_delay_t
circpad_distribution_sample_iat_delay(const circpad_state_t *state, circpad_distribution_sample_iat_delay(const circpad_state_t *state,
circpad_delay_t start_usec) circpad_delay_t delay_shift)
{ {
double val = circpad_distribution_sample(state->iat_dist); double val = circpad_distribution_sample(state->iat_dist);
/* These comparisons are safe, because the output is in the range /* These comparisons are safe, because the output is in the range
* [0, 2**32), and double has a precision of 53 bits. */ * [0, 2**32), and double has a precision of 53 bits. */
val = MAX(0, val); val = MAX(0, val);
val = MIN(val, state->range_usec); val = MIN(val, state->dist_max_sample_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. */ * is at most 2**32-1, and doubles have a precision of 53 bits. */
val += start_usec; val += delay_shift;
/* Clamp the distribution at infinite delay val */ /* Clamp the distribution at infinite delay val */
return (circpad_delay_t)MIN(tor_llround(val), CIRCPAD_DELAY_INFINITE); return (circpad_delay_t)MIN(tor_llround(val), CIRCPAD_DELAY_INFINITE);
@ -431,7 +418,6 @@ circpad_machine_sample_delay(circpad_machine_state_t *mi)
const circpad_hist_token_t *histogram = NULL; const circpad_hist_token_t *histogram = NULL;
circpad_hist_index_t curr_bin = 0; circpad_hist_index_t curr_bin = 0;
circpad_delay_t bin_start, bin_end; circpad_delay_t bin_start, bin_end;
circpad_delay_t start_usec;
/* These three must all be larger than circpad_hist_token_t, because /* These three must all be larger than circpad_hist_token_t, because
* we sum several circpad_hist_token_t values across the histogram */ * we sum several circpad_hist_token_t values across the histogram */
uint64_t curr_weight = 0; uint64_t curr_weight = 0;
@ -440,14 +426,12 @@ circpad_machine_sample_delay(circpad_machine_state_t *mi)
tor_assert(state); 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) { if (state->iat_dist.type != CIRCPAD_DIST_NONE) {
/* Sample from a fixed IAT distribution and return */ /* Sample from a fixed IAT distribution and return */
return circpad_distribution_sample_iat_delay(state, start_usec); 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) { } else if (state->token_removal != CIRCPAD_TOKEN_REMOVAL_NONE) {
/* We have a mutable histogram. Do basic sanity check and apply: */ /* We have a mutable histogram. Do basic sanity check and apply: */
if (BUG(!mi->histogram) || if (BUG(!mi->histogram) ||
@ -512,16 +496,13 @@ circpad_machine_sample_delay(circpad_machine_state_t *mi)
* function below samples from [bin_start, bin_end) */ * function below samples from [bin_start, bin_end) */
bin_end = circpad_histogram_bin_to_usec(mi, curr_bin+1); bin_end = circpad_histogram_bin_to_usec(mi, curr_bin+1);
/* Truncate the high bin in case it's the infinity bin: /* Bin edges are monotonically increasing so this is a bug. Handle it. */
* Don't actually schedule an "infinite"-1 delay */ if (BUG(bin_start > bin_end)) {
bin_end = MIN(bin_end, start_usec+state->range_usec);
// Sample uniformly between histogram[i] to histogram[i+1]-1,
// but no need to sample if they are the same timeval (aka bin 0 or bin 1).
if (bin_end <= bin_start+1)
return bin_start; return bin_start;
else }
return (circpad_delay_t)crypto_rand_uint64_range(bin_start, bin_end);
/* Sample randomly from within the bin width */
return (circpad_delay_t)crypto_rand_uint64_range(bin_start, bin_end);
} }
/** /**
@ -627,7 +608,7 @@ circpad_machine_first_higher_index(const circpad_machine_state_t *mi,
/* Don't remove from the infinity bin */ /* Don't remove from the infinity bin */
for (; bin < CIRCPAD_INFINITY_BIN(mi); bin++) { for (; bin < CIRCPAD_INFINITY_BIN(mi); bin++) {
if (mi->histogram[bin] && if (mi->histogram[bin] &&
circpad_histogram_bin_to_usec(mi, bin+1) > target_bin_usec) { histogram_get_bin_upper_bound(mi, bin) >= target_bin_usec) {
return bin; return bin;
} }
} }
@ -2083,16 +2064,92 @@ circpad_setup_machine_on_circ(circuit_t *on_circ,
on_circ->padding_machine[machine->machine_index] = machine; on_circ->padding_machine[machine->machine_index] = machine;
} }
/* These padding machines are only used for tests pending #28634. */
#ifdef TOR_UNIT_TESTS #ifdef TOR_UNIT_TESTS
/** Validate a single state of a padding machine */
static bool
padding_machine_state_is_valid(const circpad_state_t *state)
{
int b;
uint32_t tokens_count = 0;
circpad_delay_t prev_bin_edge = 0;
/* We only validate histograms */
if (!state->histogram_len) {
return true;
}
/* We need at least two bins in a histogram */
if (state->histogram_len < 2) {
log_warn(LD_GENERAL, "You can't have a histogram with less than 2 bins");
return false;
}
/* For each machine state, if it's a histogram, make sure all the
* histogram edges are well defined (i.e. are strictly monotonic). */
for (b = 0 ; b < state->histogram_len ; b++) {
/* Check that histogram edges are strictly increasing. Ignore the first
* edge since it can be zero. */
if (prev_bin_edge >= state->histogram_edges[b] && b > 0) {
log_warn(LD_GENERAL, "Histogram edges are not increasing [%u/%u]",
prev_bin_edge, state->histogram_edges[b]);
return false;
}
prev_bin_edge = state->histogram_edges[b];
/* Also count the number of tokens as we go through the histogram states */
tokens_count += state->histogram[b];
}
/* Verify that the total number of tokens is correct */
if (tokens_count != state->histogram_total_tokens) {
log_warn(LD_GENERAL, "Histogram token count is wrong [%u/%u]",
tokens_count, state->histogram_total_tokens);
return false;
}
return true;
}
/** Basic validation of padding machine */
static bool
padding_machine_is_valid(const circpad_machine_spec_t *machine)
{
int i;
/* Validate the histograms of the padding machine */
for (i = 0 ; i < machine->num_states ; i++) {
if (!padding_machine_state_is_valid(&machine->states[i])) {
return false;
}
}
return true;
}
/* Validate and register <b>machine</b> into <b>machine_list</b>. If
* <b>machine_list</b> is NULL, then just validate. */
STATIC void
register_padding_machine(circpad_machine_spec_t *machine,
smartlist_t *machine_list)
{
if (!padding_machine_is_valid(machine)) {
log_warn(LD_GENERAL, "Machine #%u is invalid. Ignoring.",
machine->machine_num);
return;
}
if (machine_list) {
smartlist_add(machine_list, machine);
}
}
/* These padding machines are only used for tests pending #28634. */
static void static void
circpad_circ_client_machine_init(void) circpad_circ_client_machine_init(void)
{ {
circpad_machine_spec_t *circ_client_machine circpad_machine_spec_t *circ_client_machine
= tor_malloc_zero(sizeof(circpad_machine_spec_t)); = tor_malloc_zero(sizeof(circpad_machine_spec_t));
// XXX: Better conditions for merge.. Or disable this machine in
// merge?
circ_client_machine->conditions.min_hops = 2; circ_client_machine->conditions.min_hops = 2;
circ_client_machine->conditions.state_mask = circ_client_machine->conditions.state_mask =
CIRCPAD_CIRC_BUILDING|CIRCPAD_CIRC_OPENED|CIRCPAD_CIRC_HAS_RELAY_EARLY; CIRCPAD_CIRC_BUILDING|CIRCPAD_CIRC_OPENED|CIRCPAD_CIRC_HAS_RELAY_EARLY;
@ -2124,19 +2181,20 @@ circpad_circ_client_machine_init(void)
circ_client_machine->states[CIRCPAD_STATE_BURST].token_removal = circ_client_machine->states[CIRCPAD_STATE_BURST].token_removal =
CIRCPAD_TOKEN_REMOVAL_CLOSEST; CIRCPAD_TOKEN_REMOVAL_CLOSEST;
// FIXME: Tune this histogram
circ_client_machine->states[CIRCPAD_STATE_BURST].histogram_len = 2; circ_client_machine->states[CIRCPAD_STATE_BURST].histogram_len = 2;
circ_client_machine->states[CIRCPAD_STATE_BURST].start_usec = 500; circ_client_machine->states[CIRCPAD_STATE_BURST].histogram_edges[0]= 500;
circ_client_machine->states[CIRCPAD_STATE_BURST].range_usec = 1000000; circ_client_machine->states[CIRCPAD_STATE_BURST].histogram_edges[1]= 1000000;
/* We have 5 tokens in the histogram, which means that all circuits will look /* We have 5 tokens in the histogram, which means that all circuits will look
* like they have 7 hops (since we start this machine after the second hop, * like they have 7 hops (since we start this machine after the second hop,
* and tokens are decremented for any valid hops, and fake extends are * and tokens are decremented for any valid hops, and fake extends are
* used after that -- 2+5==7). */ * used after that -- 2+5==7). */
circ_client_machine->states[CIRCPAD_STATE_BURST].histogram[0] = 5; circ_client_machine->states[CIRCPAD_STATE_BURST].histogram[0] = 5;
circ_client_machine->states[CIRCPAD_STATE_BURST].histogram_total_tokens = 5; circ_client_machine->states[CIRCPAD_STATE_BURST].histogram_total_tokens = 5;
circ_client_machine->machine_num = smartlist_len(origin_padding_machines); circ_client_machine->machine_num = smartlist_len(origin_padding_machines);
smartlist_add(origin_padding_machines, circ_client_machine); register_padding_machine(circ_client_machine, origin_padding_machines);
} }
static void static void
@ -2183,8 +2241,9 @@ circpad_circ_responder_machine_init(void)
circ_responder_machine->states[CIRCPAD_STATE_BURST].use_rtt_estimate = 1; circ_responder_machine->states[CIRCPAD_STATE_BURST].use_rtt_estimate = 1;
/* The histogram is 2 bins: an empty one, and infinity */ /* The histogram is 2 bins: an empty one, and infinity */
circ_responder_machine->states[CIRCPAD_STATE_BURST].histogram_len = 2; circ_responder_machine->states[CIRCPAD_STATE_BURST].histogram_len = 2;
circ_responder_machine->states[CIRCPAD_STATE_BURST].start_usec = 5000; circ_responder_machine->states[CIRCPAD_STATE_BURST].histogram_edges[0]= 500;
circ_responder_machine->states[CIRCPAD_STATE_BURST].range_usec = 1000000; circ_responder_machine->states[CIRCPAD_STATE_BURST].histogram_edges[1] =
1000000;
/* During burst state we wait forever for padding to arrive. /* During burst state we wait forever for padding to arrive.
We are waiting for a padding cell from the client to come in, so that we We are waiting for a padding cell from the client to come in, so that we
@ -2215,8 +2274,14 @@ circpad_circ_responder_machine_init(void)
before you send a padding response */ before you send a padding response */
circ_responder_machine->states[CIRCPAD_STATE_GAP].use_rtt_estimate = 1; circ_responder_machine->states[CIRCPAD_STATE_GAP].use_rtt_estimate = 1;
circ_responder_machine->states[CIRCPAD_STATE_GAP].histogram_len = 6; circ_responder_machine->states[CIRCPAD_STATE_GAP].histogram_len = 6;
circ_responder_machine->states[CIRCPAD_STATE_GAP].start_usec = 5000; /* Specify histogram bins */
circ_responder_machine->states[CIRCPAD_STATE_GAP].range_usec = 1000000; circ_responder_machine->states[CIRCPAD_STATE_GAP].histogram_edges[0]= 500;
circ_responder_machine->states[CIRCPAD_STATE_GAP].histogram_edges[1]= 1000;
circ_responder_machine->states[CIRCPAD_STATE_GAP].histogram_edges[2]= 2000;
circ_responder_machine->states[CIRCPAD_STATE_GAP].histogram_edges[3]= 4000;
circ_responder_machine->states[CIRCPAD_STATE_GAP].histogram_edges[4]= 8000;
circ_responder_machine->states[CIRCPAD_STATE_GAP].histogram_edges[5]= 16000;
/* Specify histogram tokens */
circ_responder_machine->states[CIRCPAD_STATE_GAP].histogram[0] = 0; circ_responder_machine->states[CIRCPAD_STATE_GAP].histogram[0] = 0;
circ_responder_machine->states[CIRCPAD_STATE_GAP].histogram[1] = 1; circ_responder_machine->states[CIRCPAD_STATE_GAP].histogram[1] = 1;
circ_responder_machine->states[CIRCPAD_STATE_GAP].histogram[2] = 2; circ_responder_machine->states[CIRCPAD_STATE_GAP].histogram[2] = 2;
@ -2224,11 +2289,12 @@ circpad_circ_responder_machine_init(void)
circ_responder_machine->states[CIRCPAD_STATE_GAP].histogram[4] = 1; circ_responder_machine->states[CIRCPAD_STATE_GAP].histogram[4] = 1;
/* Total number of tokens */ /* Total number of tokens */
circ_responder_machine->states[CIRCPAD_STATE_GAP].histogram_total_tokens = 6; circ_responder_machine->states[CIRCPAD_STATE_GAP].histogram_total_tokens = 6;
circ_responder_machine->states[CIRCPAD_STATE_GAP].token_removal = circ_responder_machine->states[CIRCPAD_STATE_GAP].token_removal =
CIRCPAD_TOKEN_REMOVAL_CLOSEST_USEC; CIRCPAD_TOKEN_REMOVAL_CLOSEST_USEC;
circ_responder_machine->machine_num = smartlist_len(relay_padding_machines); circ_responder_machine->machine_num = smartlist_len(relay_padding_machines);
smartlist_add(relay_padding_machines, circ_responder_machine); register_padding_machine(circ_responder_machine, relay_padding_machines);
} }
#endif #endif

103
src/core/or/circuitpadding.h
View File

@ -228,13 +228,18 @@ typedef uint16_t circpad_statenum_t;
#define CIRCPAD_STATENUM_MAX (UINT16_MAX) #define CIRCPAD_STATENUM_MAX (UINT16_MAX)
/** A histogram is used to sample padding delays given a machine state. This /** A histogram is used to sample padding delays given a machine state. This
* constant defines the maximum histogram width (i.e. the max number of bins) * constant defines the maximum histogram width (i.e. the max number of bins).
* *
* Each histogram bin is twice as large as the previous. Two exceptions: The * The current limit is arbitrary and could be raised if there is a need,
* first bin has zero width (which means that minimum delay is applied to the * however too many bins will be hard to serialize in the future.
* next padding cell), and the last bin (infinity bin) has infinite width *
* (which means that the next padding cell will be delayed infinitely). */ * Memory concerns are not so great here since the corresponding histogram and
#define CIRCPAD_MAX_HISTOGRAM_LEN (sizeof(circpad_delay_t)*8 + 1) * histogram_edges arrays are global and not per-circuit.
*
* If we ever upgrade this to a value that can't be represented by 8-bits we
* also need to upgrade circpad_hist_index_t.
*/
#define CIRCPAD_MAX_HISTOGRAM_LEN (100)
/** /**
* A state of a padding state machine. The information here are immutable and * A state of a padding state machine. The information here are immutable and
@ -248,38 +253,60 @@ typedef uint16_t circpad_statenum_t;
* or the consensus. * or the consensus.
*/ */
typedef struct circpad_state_t { typedef struct circpad_state_t {
/** If a histogram is used for this state, this specifies the number of bins /**
* of this histogram. Histograms must have at least 2 bins. * If a histogram is used for this state, this specifies the number of bins
* of this histogram. Histograms must have at least 2 bins.
* *
* If a delay probability distribution is used for this state, this is set * In particular, the following histogram:
* to 0. */ *
* Tokens
* +
* 10 | +----+
* 9 | | | +---------+
* 8 | | | | |
* 7 | | | +-----+ |
* 6 +----+ Bin+-----+ | +---------------+
* 5 | | #1 | | | | |
* | Bin| | Bin | Bin | Bin #4 | Bin #5 |
* | #0 | | #2 | #3 | | (infinity bin)|
* | | | | | | |
* | | | | | | |
* 0 +----+----+-----+-----+---------+---------------+
* 0 100 200 350 500 1000 ∞ microseconds
*
* would be specified the following way:
* histogram_len = 6;
* histogram[] = { 6, 10, 6, 7, 9, 6 }
* histogram_edges[] = { 0, 100, 200, 350, 500, 1000 }
*
* The final bin is called the "infinity bin" and if it's chosen we don't
* schedule any padding. The infinity bin is strange because its lower edge
* is the max value of possible non-infinite delay allowed by this histogram,
* and its upper edge is CIRCPAD_DELAY_INFINITE. You can tell if the infinity
* bin is chosen by inspecting its bin index or inspecting its upper edge.
*
* If a delay probability distribution is used for this state, this is set
* to 0. */
circpad_hist_index_t histogram_len; circpad_hist_index_t histogram_len;
/** The histogram itself: an array of uint16s of tokens, whose /** The histogram itself: an array of uint16s of tokens, whose
* widths are exponentially spaced, in microseconds */ * widths are exponentially spaced, in microseconds.
*
* This array must have histogram_len elements that are strictly
* monotonically increasing. */
circpad_hist_token_t histogram[CIRCPAD_MAX_HISTOGRAM_LEN]; circpad_hist_token_t histogram[CIRCPAD_MAX_HISTOGRAM_LEN];
/* The histogram bin edges in usec.
*
* Each element of this array specifies the left edge of the corresponding
* bin. The rightmost edge is always infinity and is not specified in this
* array.
*
* This array must have histogram_len elements. */
circpad_delay_t histogram_edges[CIRCPAD_MAX_HISTOGRAM_LEN+1];
/** Total number of tokens in this histogram. This is a constant and is *not* /** Total number of tokens in this histogram. This is a constant and is *not*
* decremented every time we spend a token. It's used for initializing and * decremented every time we spend a token. It's used for initializing and
* refilling the histogram. */ * refilling the histogram. */
uint32_t histogram_total_tokens; 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 * Represents a delay probability distribution (aka IAT distribution). It's a
* parametrized way of encoding inter-packet delay information in * parametrized way of encoding inter-packet delay information in
@ -292,6 +319,16 @@ typedef struct circpad_state_t {
* results of sampling from this distribution (range_sec is used as a max). * results of sampling from this distribution (range_sec is used as a max).
*/ */
circpad_distribution_t iat_dist; circpad_distribution_t iat_dist;
/* If a delay probability distribution is used, this is used as the max
* 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 * The length dist is a parameterized way of encoding how long this
@ -686,9 +723,17 @@ circpad_send_command_to_hop,(struct origin_circuit_t *circ, uint8_t hopnum,
uint8_t relay_command, const uint8_t *payload, uint8_t relay_command, const uint8_t *payload,
ssize_t payload_len)); ssize_t payload_len));
STATIC circpad_delay_t
histogram_get_bin_upper_bound(const circpad_machine_state_t *mi,
circpad_hist_index_t bin);
#ifdef TOR_UNIT_TESTS #ifdef TOR_UNIT_TESTS
extern smartlist_t *origin_padding_machines; extern smartlist_t *origin_padding_machines;
extern smartlist_t *relay_padding_machines; extern smartlist_t *relay_padding_machines;
STATIC void
register_padding_machine(circpad_machine_spec_t *machine,
smartlist_t *machine_list);
#endif #endif
#endif #endif

138
src/test/test_circuitpadding.c
View File

@ -333,7 +333,7 @@ test_circuitpadding_rtt(void *arg)
OP_EQ, OP_EQ,
relay_side->padding_info[0]->rtt_estimate_usec+ relay_side->padding_info[0]->rtt_estimate_usec+
circpad_machine_current_state( circpad_machine_current_state(
relay_side->padding_info[0])->start_usec); relay_side->padding_info[0])->histogram_edges[0]);
circpad_cell_event_nonpadding_received((circuit_t*)relay_side); circpad_cell_event_nonpadding_received((circuit_t*)relay_side);
circpad_cell_event_nonpadding_received((circuit_t*)relay_side); circpad_cell_event_nonpadding_received((circuit_t*)relay_side);
@ -349,7 +349,7 @@ test_circuitpadding_rtt(void *arg)
OP_EQ, OP_EQ,
relay_side->padding_info[0]->rtt_estimate_usec+ relay_side->padding_info[0]->rtt_estimate_usec+
circpad_machine_current_state( circpad_machine_current_state(
relay_side->padding_info[0])->start_usec); relay_side->padding_info[0])->histogram_edges[0]);
/* Test 2: Termination of RTT measurement (from the previous test) */ /* Test 2: Termination of RTT measurement (from the previous test) */
tt_int_op(relay_side->padding_info[0]->stop_rtt_update, OP_EQ, 1); tt_int_op(relay_side->padding_info[0]->stop_rtt_update, OP_EQ, 1);
@ -367,7 +367,7 @@ test_circuitpadding_rtt(void *arg)
OP_EQ, OP_EQ,
relay_side->padding_info[0]->rtt_estimate_usec+ relay_side->padding_info[0]->rtt_estimate_usec+
circpad_machine_current_state( circpad_machine_current_state(
relay_side->padding_info[0])->start_usec); relay_side->padding_info[0])->histogram_edges[0]);
/* Test 3: Make sure client side machine properly ignores RTT */ /* Test 3: Make sure client side machine properly ignores RTT */
circpad_cell_event_nonpadding_received((circuit_t*)client_side); circpad_cell_event_nonpadding_received((circuit_t*)client_side);
@ -383,7 +383,7 @@ test_circuitpadding_rtt(void *arg)
tt_int_op(circpad_histogram_bin_to_usec(client_side->padding_info[0], 0), tt_int_op(circpad_histogram_bin_to_usec(client_side->padding_info[0], 0),
OP_EQ, OP_EQ,
circpad_machine_current_state( circpad_machine_current_state(
client_side->padding_info[0])->start_usec); client_side->padding_info[0])->histogram_edges[0]);
done: done:
free_fake_orcirc(relay_side); free_fake_orcirc(relay_side);
circuitmux_detach_all_circuits(dummy_channel.cmux, NULL); circuitmux_detach_all_circuits(dummy_channel.cmux, NULL);
@ -414,19 +414,23 @@ helper_create_basic_machine(void)
circ_client_machine.states[CIRCPAD_STATE_BURST]. circ_client_machine.states[CIRCPAD_STATE_BURST].
next_state[CIRCPAD_EVENT_NONPADDING_SENT] = CIRCPAD_STATE_CANCEL; next_state[CIRCPAD_EVENT_NONPADDING_SENT] = CIRCPAD_STATE_CANCEL;
// FIXME: Is this what we want?
circ_client_machine.states[CIRCPAD_STATE_BURST].token_removal = circ_client_machine.states[CIRCPAD_STATE_BURST].token_removal =
CIRCPAD_TOKEN_REMOVAL_HIGHER; CIRCPAD_TOKEN_REMOVAL_HIGHER;
// FIXME: Tune this histogram
circ_client_machine.states[CIRCPAD_STATE_BURST].histogram_len = 5; circ_client_machine.states[CIRCPAD_STATE_BURST].histogram_len = 5;
circ_client_machine.states[CIRCPAD_STATE_BURST].start_usec = 500;
circ_client_machine.states[CIRCPAD_STATE_BURST].range_usec = 1000000; circ_client_machine.states[CIRCPAD_STATE_BURST].histogram_edges[0] = 500;
circ_client_machine.states[CIRCPAD_STATE_BURST].histogram_edges[1] = 2500;
circ_client_machine.states[CIRCPAD_STATE_BURST].histogram_edges[2] = 5000;
circ_client_machine.states[CIRCPAD_STATE_BURST].histogram_edges[3] = 10000;
circ_client_machine.states[CIRCPAD_STATE_BURST].histogram_edges[4] = 20000;
circ_client_machine.states[CIRCPAD_STATE_BURST].histogram[0] = 1; circ_client_machine.states[CIRCPAD_STATE_BURST].histogram[0] = 1;
circ_client_machine.states[CIRCPAD_STATE_BURST].histogram[1] = 0; circ_client_machine.states[CIRCPAD_STATE_BURST].histogram[1] = 0;
circ_client_machine.states[CIRCPAD_STATE_BURST].histogram[2] = 2; circ_client_machine.states[CIRCPAD_STATE_BURST].histogram[2] = 2;
circ_client_machine.states[CIRCPAD_STATE_BURST].histogram[3] = 2; circ_client_machine.states[CIRCPAD_STATE_BURST].histogram[3] = 2;
circ_client_machine.states[CIRCPAD_STATE_BURST].histogram[4] = 2; circ_client_machine.states[CIRCPAD_STATE_BURST].histogram[4] = 2;
circ_client_machine.states[CIRCPAD_STATE_BURST].histogram_total_tokens = 7; circ_client_machine.states[CIRCPAD_STATE_BURST].histogram_total_tokens = 7;
circ_client_machine.states[CIRCPAD_STATE_BURST].use_rtt_estimate = 1; circ_client_machine.states[CIRCPAD_STATE_BURST].use_rtt_estimate = 1;
@ -458,15 +462,25 @@ helper_create_machine_with_big_histogram(circpad_removal_t removal_strategy)
burst_state->token_removal = CIRCPAD_TOKEN_REMOVAL_HIGHER; burst_state->token_removal = CIRCPAD_TOKEN_REMOVAL_HIGHER;
burst_state->histogram_len = BIG_HISTOGRAM_LEN; burst_state->histogram_len = BIG_HISTOGRAM_LEN;
burst_state->start_usec = 0;
burst_state->range_usec = 1000;
int n_tokens = 0; int n_tokens = 0;
for (int i = 0; i < BIG_HISTOGRAM_LEN ; i++) { int i;
for (i = 0; i < BIG_HISTOGRAM_LEN ; i++) {
burst_state->histogram[i] = tokens_per_bin; burst_state->histogram[i] = tokens_per_bin;
n_tokens += tokens_per_bin; n_tokens += tokens_per_bin;
} }
burst_state->histogram_edges[0] = 0;
burst_state->histogram_edges[1] = 1;
burst_state->histogram_edges[2] = 7;
burst_state->histogram_edges[3] = 15;
burst_state->histogram_edges[4] = 31;
burst_state->histogram_edges[5] = 62;
burst_state->histogram_edges[6] = 125;
burst_state->histogram_edges[7] = 250;
burst_state->histogram_edges[8] = 500;
burst_state->histogram_edges[9] = 1000;
burst_state->histogram_total_tokens = n_tokens; burst_state->histogram_total_tokens = n_tokens;
burst_state->length_dist.type = CIRCPAD_DIST_UNIFORM; burst_state->length_dist.type = CIRCPAD_DIST_UNIFORM;
burst_state->length_dist.param1 = n_tokens; burst_state->length_dist.param1 = n_tokens;
@ -527,12 +541,20 @@ test_circuitpadding_token_removal_higher(void *arg)
/* Test left boundaries of each histogram bin: */ /* Test left boundaries of each histogram bin: */
const circpad_delay_t bin_left_bounds[] = const circpad_delay_t bin_left_bounds[] =
{0, 1, 7, 15, 31, 62, 125, 250, 500, CIRCPAD_DELAY_INFINITE}; {0, 1, 7, 15, 31, 62, 125, 250, 500, 1000, CIRCPAD_DELAY_INFINITE};
for (int i = 0; i < BIG_HISTOGRAM_LEN ; i++) { for (int i = 0; i <= BIG_HISTOGRAM_LEN ; i++) {
tt_uint_op(bin_left_bounds[i], OP_EQ, tt_uint_op(bin_left_bounds[i], OP_EQ,
circpad_histogram_bin_to_usec(mi, i)); circpad_histogram_bin_to_usec(mi, i));
} }
/* Test right boundaries of each histogram bin: */
const circpad_delay_t bin_right_bounds[] =
{0, 6, 14, 30, 61, 124, 249, 499, 999, CIRCPAD_DELAY_INFINITE-1};
for (int i = 0; i < BIG_HISTOGRAM_LEN ; i++) {
tt_uint_op(bin_right_bounds[i], OP_EQ,
histogram_get_bin_upper_bound(mi, i));
}
/* Check that all bins have two tokens right now */ /* Check that all bins have two tokens right now */
for (int i = 0; i < BIG_HISTOGRAM_LEN ; i++) { for (int i = 0; i < BIG_HISTOGRAM_LEN ; i++) {
tt_int_op(mi->histogram[i], OP_EQ, 2); tt_int_op(mi->histogram[i], OP_EQ, 2);
@ -576,8 +598,8 @@ test_circuitpadding_token_removal_higher(void *arg)
/* Test below the lowest bin, for coverage */ /* Test below the lowest bin, for coverage */
tt_int_op(client_side->padding_info[0]->current_state, OP_EQ, tt_int_op(client_side->padding_info[0]->current_state, OP_EQ,
CIRCPAD_STATE_BURST); CIRCPAD_STATE_BURST);
circ_client_machine.states[CIRCPAD_STATE_BURST].start_usec = 100; circ_client_machine.states[CIRCPAD_STATE_BURST].histogram_edges[0] = 100;
mi->padding_scheduled_at_usec = current_time - 1; mi->padding_scheduled_at_usec = current_time;
circpad_machine_remove_token(mi); circpad_machine_remove_token(mi);
tt_int_op(mi->histogram[0], OP_EQ, 1); tt_int_op(mi->histogram[0], OP_EQ, 1);
@ -624,8 +646,8 @@ test_circuitpadding_token_removal_lower(void *arg)
/* Test left boundaries of each histogram bin: */ /* Test left boundaries of each histogram bin: */
const circpad_delay_t bin_left_bounds[] = const circpad_delay_t bin_left_bounds[] =
{0, 1, 7, 15, 31, 62, 125, 250, 500, CIRCPAD_DELAY_INFINITE}; {0, 1, 7, 15, 31, 62, 125, 250, 500, 1000, CIRCPAD_DELAY_INFINITE};
for (int i = 0; i < BIG_HISTOGRAM_LEN ; i++) { for (int i = 0; i <= BIG_HISTOGRAM_LEN ; i++) {
tt_uint_op(bin_left_bounds[i], OP_EQ, tt_uint_op(bin_left_bounds[i], OP_EQ,
circpad_histogram_bin_to_usec(mi, i)); circpad_histogram_bin_to_usec(mi, i));
} }
@ -673,7 +695,8 @@ test_circuitpadding_token_removal_lower(void *arg)
/* Test above the highest bin, for coverage */ /* Test above the highest bin, for coverage */
tt_int_op(client_side->padding_info[0]->current_state, OP_EQ, tt_int_op(client_side->padding_info[0]->current_state, OP_EQ,
CIRCPAD_STATE_BURST); CIRCPAD_STATE_BURST);
circ_client_machine.states[CIRCPAD_STATE_BURST].start_usec = 100; circ_client_machine.states[CIRCPAD_STATE_BURST].
histogram_edges[BIG_HISTOGRAM_LEN-2] = 100;
mi->padding_scheduled_at_usec = current_time - 29202; mi->padding_scheduled_at_usec = current_time - 29202;
circpad_machine_remove_token(mi); circpad_machine_remove_token(mi);
tt_int_op(mi->histogram[BIG_HISTOGRAM_LEN-2], OP_EQ, 1); tt_int_op(mi->histogram[BIG_HISTOGRAM_LEN-2], OP_EQ, 1);
@ -721,8 +744,8 @@ test_circuitpadding_closest_token_removal(void *arg)
/* Test left boundaries of each histogram bin: */ /* Test left boundaries of each histogram bin: */
const circpad_delay_t bin_left_bounds[] = const circpad_delay_t bin_left_bounds[] =
{0, 1, 7, 15, 31, 62, 125, 250, 500, CIRCPAD_DELAY_INFINITE}; {0, 1, 7, 15, 31, 62, 125, 250, 500, 1000, CIRCPAD_DELAY_INFINITE};
for (int i = 0; i < BIG_HISTOGRAM_LEN ; i++) { for (int i = 0; i <= BIG_HISTOGRAM_LEN ; i++) {
tt_uint_op(bin_left_bounds[i], OP_EQ, tt_uint_op(bin_left_bounds[i], OP_EQ,
circpad_histogram_bin_to_usec(mi, i)); circpad_histogram_bin_to_usec(mi, i));
} }
@ -769,7 +792,9 @@ test_circuitpadding_closest_token_removal(void *arg)
/* Test below the lowest bin, for coverage */ /* Test below the lowest bin, for coverage */
tt_int_op(client_side->padding_info[0]->current_state, OP_EQ, tt_int_op(client_side->padding_info[0]->current_state, OP_EQ,
CIRCPAD_STATE_BURST); CIRCPAD_STATE_BURST);
circ_client_machine.states[CIRCPAD_STATE_BURST].start_usec = 100; circ_client_machine.states[CIRCPAD_STATE_BURST].histogram_edges[0] = 100;
circ_client_machine.states[CIRCPAD_STATE_BURST].histogram_edges[1] = 101;
circ_client_machine.states[CIRCPAD_STATE_BURST].histogram_edges[2] = 120;
mi->padding_scheduled_at_usec = current_time - 102; mi->padding_scheduled_at_usec = current_time - 102;
mi->histogram[0] = 0; mi->histogram[0] = 0;
circpad_machine_remove_token(mi); circpad_machine_remove_token(mi);
@ -778,7 +803,6 @@ test_circuitpadding_closest_token_removal(void *arg)
/* Test above the highest bin, for coverage */ /* Test above the highest bin, for coverage */
tt_int_op(client_side->padding_info[0]->current_state, OP_EQ, tt_int_op(client_side->padding_info[0]->current_state, OP_EQ,
CIRCPAD_STATE_BURST); CIRCPAD_STATE_BURST);
circ_client_machine.states[CIRCPAD_STATE_BURST].start_usec = 100;
mi->padding_scheduled_at_usec = current_time - 29202; mi->padding_scheduled_at_usec = current_time - 29202;
circpad_machine_remove_token(mi); circpad_machine_remove_token(mi);
tt_int_op(mi->histogram[BIG_HISTOGRAM_LEN-2], OP_EQ, 1); tt_int_op(mi->histogram[BIG_HISTOGRAM_LEN-2], OP_EQ, 1);
@ -826,8 +850,8 @@ test_circuitpadding_closest_token_removal_usec(void *arg)
/* Test left boundaries of each histogram bin: */ /* Test left boundaries of each histogram bin: */
const circpad_delay_t bin_left_bounds[] = const circpad_delay_t bin_left_bounds[] =
{0, 1, 7, 15, 31, 62, 125, 250, 500, CIRCPAD_DELAY_INFINITE}; {0, 1, 7, 15, 31, 62, 125, 250, 500, 1000, CIRCPAD_DELAY_INFINITE};
for (int i = 0; i < BIG_HISTOGRAM_LEN ; i++) { for (int i = 0; i <= BIG_HISTOGRAM_LEN ; i++) {
tt_uint_op(bin_left_bounds[i], OP_EQ, tt_uint_op(bin_left_bounds[i], OP_EQ,
circpad_histogram_bin_to_usec(mi, i)); circpad_histogram_bin_to_usec(mi, i));
} }
@ -877,7 +901,9 @@ test_circuitpadding_closest_token_removal_usec(void *arg)
/* Test below the lowest bin, for coverage */ /* Test below the lowest bin, for coverage */
tt_int_op(client_side->padding_info[0]->current_state, OP_EQ, tt_int_op(client_side->padding_info[0]->current_state, OP_EQ,
CIRCPAD_STATE_BURST); CIRCPAD_STATE_BURST);
circ_client_machine.states[CIRCPAD_STATE_BURST].start_usec = 100; circ_client_machine.states[CIRCPAD_STATE_BURST].histogram_edges[0] = 100;
circ_client_machine.states[CIRCPAD_STATE_BURST].histogram_edges[1] = 101;
circ_client_machine.states[CIRCPAD_STATE_BURST].histogram_edges[2] = 120;
mi->padding_scheduled_at_usec = current_time - 102; mi->padding_scheduled_at_usec = current_time - 102;
mi->histogram[0] = 0; mi->histogram[0] = 0;
circpad_machine_remove_token(mi); circpad_machine_remove_token(mi);
@ -886,7 +912,8 @@ test_circuitpadding_closest_token_removal_usec(void *arg)
/* Test above the highest bin, for coverage */ /* Test above the highest bin, for coverage */
tt_int_op(client_side->padding_info[0]->current_state, OP_EQ, tt_int_op(client_side->padding_info[0]->current_state, OP_EQ,
CIRCPAD_STATE_BURST); CIRCPAD_STATE_BURST);
circ_client_machine.states[CIRCPAD_STATE_BURST].start_usec = 100; circ_client_machine.states[CIRCPAD_STATE_BURST].
histogram_edges[BIG_HISTOGRAM_LEN-2] = 100;
mi->padding_scheduled_at_usec = current_time - 29202; mi->padding_scheduled_at_usec = current_time - 29202;
circpad_machine_remove_token(mi); circpad_machine_remove_token(mi);
tt_int_op(mi->histogram[BIG_HISTOGRAM_LEN-2], OP_EQ, 1); tt_int_op(mi->histogram[BIG_HISTOGRAM_LEN-2], OP_EQ, 1);
@ -1043,7 +1070,7 @@ test_circuitpadding_tokens(void *arg)
// Test 1: converting usec->bin->usec->bin // Test 1: converting usec->bin->usec->bin
// Bin 0+1 have different semantics. // Bin 0+1 have different semantics.
for (circpad_delay_t i = 0; i <= state->start_usec+1; i++) { for (circpad_delay_t i = 0; i <= state->histogram_edges[0]; i++) {
int bin = circpad_histogram_usec_to_bin(client_side->padding_info[0], int bin = circpad_histogram_usec_to_bin(client_side->padding_info[0],
i); i);
circpad_delay_t usec = circpad_delay_t usec =
@ -1053,8 +1080,9 @@ test_circuitpadding_tokens(void *arg)
tt_int_op(bin, OP_EQ, bin2); tt_int_op(bin, OP_EQ, bin2);
tt_int_op(i, OP_LE, usec); tt_int_op(i, OP_LE, usec);
} }
for (circpad_delay_t i = state->start_usec+1; for (circpad_delay_t i = state->histogram_edges[0]+1;
i <= state->start_usec + state->range_usec; i++) { i <= state->histogram_edges[0] +
state->histogram_edges[state->histogram_len-2]; i++) {
int bin = circpad_histogram_usec_to_bin(client_side->padding_info[0], int bin = circpad_histogram_usec_to_bin(client_side->padding_info[0],
i); i);
circpad_delay_t usec = circpad_delay_t usec =
@ -1106,8 +1134,7 @@ test_circuitpadding_tokens(void *arg)
/* 2.c. Bin 0 */ /* 2.c. Bin 0 */
{ {
tt_int_op(mi->histogram[0], OP_EQ, 1); tt_int_op(mi->histogram[0], OP_EQ, 1);
circpad_machine_remove_higher_token(mi, circpad_machine_remove_higher_token(mi, state->histogram_edges[0]/2);
state->start_usec/2);
tt_int_op(mi->histogram[0], OP_EQ, 0); tt_int_op(mi->histogram[0], OP_EQ, 0);
} }
@ -1126,8 +1153,7 @@ test_circuitpadding_tokens(void *arg)
/* 3.a. Bin 0 */ /* 3.a. Bin 0 */
{ {
tt_int_op(mi->histogram[0], OP_EQ, 1); tt_int_op(mi->histogram[0], OP_EQ, 1);
circpad_machine_remove_higher_token(mi, circpad_machine_remove_higher_token(mi, state->histogram_edges[0]/2);
state->start_usec/2);
tt_int_op(mi->histogram[0], OP_EQ, 0); tt_int_op(mi->histogram[0], OP_EQ, 0);
} }
@ -1615,15 +1641,20 @@ helper_create_conditional_machine(void)
ret->states[CIRCPAD_STATE_BURST]. ret->states[CIRCPAD_STATE_BURST].
next_state[CIRCPAD_EVENT_LENGTH_COUNT] = CIRCPAD_STATE_END; next_state[CIRCPAD_EVENT_LENGTH_COUNT] = CIRCPAD_STATE_END;
/* Use EXACT removal strategy, otherwise setup_tokens() does not work */
ret->states[CIRCPAD_STATE_BURST].token_removal = ret->states[CIRCPAD_STATE_BURST].token_removal =
CIRCPAD_TOKEN_REMOVAL_NONE; CIRCPAD_TOKEN_REMOVAL_EXACT;
ret->states[CIRCPAD_STATE_BURST].histogram_len = 3; ret->states[CIRCPAD_STATE_BURST].histogram_len = 3;
ret->states[CIRCPAD_STATE_BURST].start_usec = 0;
ret->states[CIRCPAD_STATE_BURST].range_usec = 1000000; ret->states[CIRCPAD_STATE_BURST].histogram_edges[0] = 0;
ret->states[CIRCPAD_STATE_BURST].histogram_edges[1] = 1;
ret->states[CIRCPAD_STATE_BURST].histogram_edges[2] = 1000000;
ret->states[CIRCPAD_STATE_BURST].histogram[0] = 6; ret->states[CIRCPAD_STATE_BURST].histogram[0] = 6;
ret->states[CIRCPAD_STATE_BURST].histogram[1] = 0; ret->states[CIRCPAD_STATE_BURST].histogram[1] = 0;
ret->states[CIRCPAD_STATE_BURST].histogram[1] = 0; ret->states[CIRCPAD_STATE_BURST].histogram[2] = 0;
ret->states[CIRCPAD_STATE_BURST].histogram_total_tokens = 6; ret->states[CIRCPAD_STATE_BURST].histogram_total_tokens = 6;
ret->states[CIRCPAD_STATE_BURST].use_rtt_estimate = 0; ret->states[CIRCPAD_STATE_BURST].use_rtt_estimate = 0;
ret->states[CIRCPAD_STATE_BURST].length_includes_nonpadding = 1; ret->states[CIRCPAD_STATE_BURST].length_includes_nonpadding = 1;
@ -1654,8 +1685,7 @@ helper_create_conditional_machines(void)
add->conditions.state_mask = CIRCPAD_CIRC_BUILDING| add->conditions.state_mask = CIRCPAD_CIRC_BUILDING|
CIRCPAD_CIRC_NO_STREAMS|CIRCPAD_CIRC_HAS_RELAY_EARLY; CIRCPAD_CIRC_NO_STREAMS|CIRCPAD_CIRC_HAS_RELAY_EARLY;
add->conditions.purpose_mask = CIRCPAD_PURPOSE_ALL; add->conditions.purpose_mask = CIRCPAD_PURPOSE_ALL;
register_padding_machine(add, origin_padding_machines);
smartlist_add(origin_padding_machines, add);
add = helper_create_conditional_machine(); add = helper_create_conditional_machine();
add->machine_num = 3; add->machine_num = 3;
@ -1674,15 +1704,15 @@ helper_create_conditional_machines(void)
add->conditions.state_mask = CIRCPAD_CIRC_OPENED| add->conditions.state_mask = CIRCPAD_CIRC_OPENED|
CIRCPAD_CIRC_STREAMS|CIRCPAD_CIRC_HAS_NO_RELAY_EARLY; CIRCPAD_CIRC_STREAMS|CIRCPAD_CIRC_HAS_NO_RELAY_EARLY;
add->conditions.purpose_mask = CIRCPAD_PURPOSE_ALL; add->conditions.purpose_mask = CIRCPAD_PURPOSE_ALL;
smartlist_add(origin_padding_machines, add); register_padding_machine(add, origin_padding_machines);
add = helper_create_conditional_machine(); add = helper_create_conditional_machine();
add->machine_num = 2; add->machine_num = 2;
smartlist_add(relay_padding_machines, add); register_padding_machine(add, relay_padding_machines);
add = helper_create_conditional_machine(); add = helper_create_conditional_machine();
add->machine_num = 3; add->machine_num = 3;
smartlist_add(relay_padding_machines, add); register_padding_machine(add, relay_padding_machines);
} }
void void
@ -2069,48 +2099,48 @@ helper_circpad_circ_distribution_machine_setup(int min, int max)
zero_st->iat_dist.type = CIRCPAD_DIST_UNIFORM; zero_st->iat_dist.type = CIRCPAD_DIST_UNIFORM;
zero_st->iat_dist.param1 = min; zero_st->iat_dist.param1 = min;
zero_st->iat_dist.param2 = max; zero_st->iat_dist.param2 = max;
zero_st->start_usec = min; zero_st->dist_added_shift_usec = min;
zero_st->range_usec = max; zero_st->dist_max_sample_usec = max;
circpad_state_t *first_st = &circ_client_machine.states[1]; circpad_state_t *first_st = &circ_client_machine.states[1];
first_st->next_state[CIRCPAD_EVENT_NONPADDING_RECV] = 2; first_st->next_state[CIRCPAD_EVENT_NONPADDING_RECV] = 2;
first_st->iat_dist.type = CIRCPAD_DIST_LOGISTIC; first_st->iat_dist.type = CIRCPAD_DIST_LOGISTIC;
first_st->iat_dist.param1 = min; first_st->iat_dist.param1 = min;
first_st->iat_dist.param2 = max; first_st->iat_dist.param2 = max;
first_st->start_usec = min; first_st->dist_added_shift_usec = min;
first_st->range_usec = max; first_st->dist_max_sample_usec = max;
circpad_state_t *second_st = &circ_client_machine.states[2]; circpad_state_t *second_st = &circ_client_machine.states[2];
second_st->next_state[CIRCPAD_EVENT_NONPADDING_RECV] = 3; second_st->next_state[CIRCPAD_EVENT_NONPADDING_RECV] = 3;
second_st->iat_dist.type = CIRCPAD_DIST_LOG_LOGISTIC; second_st->iat_dist.type = CIRCPAD_DIST_LOG_LOGISTIC;
second_st->iat_dist.param1 = min; second_st->iat_dist.param1 = min;
second_st->iat_dist.param2 = max; second_st->iat_dist.param2 = max;
second_st->start_usec = min; second_st->dist_added_shift_usec = min;
second_st->range_usec = max; second_st->dist_max_sample_usec = max;
circpad_state_t *third_st = &circ_client_machine.states[3]; circpad_state_t *third_st = &circ_client_machine.states[3];
third_st->next_state[CIRCPAD_EVENT_NONPADDING_RECV] = 4; third_st->next_state[CIRCPAD_EVENT_NONPADDING_RECV] = 4;
third_st->iat_dist.type = CIRCPAD_DIST_GEOMETRIC; third_st->iat_dist.type = CIRCPAD_DIST_GEOMETRIC;
third_st->iat_dist.param1 = min; third_st->iat_dist.param1 = min;
third_st->iat_dist.param2 = max; third_st->iat_dist.param2 = max;
third_st->start_usec = min; third_st->dist_added_shift_usec = min;
third_st->range_usec = max; third_st->dist_max_sample_usec = max;
circpad_state_t *fourth_st = &circ_client_machine.states[4]; circpad_state_t *fourth_st = &circ_client_machine.states[4];
fourth_st->next_state[CIRCPAD_EVENT_NONPADDING_RECV] = 5; fourth_st->next_state[CIRCPAD_EVENT_NONPADDING_RECV] = 5;
fourth_st->iat_dist.type = CIRCPAD_DIST_WEIBULL; fourth_st->iat_dist.type = CIRCPAD_DIST_WEIBULL;
fourth_st->iat_dist.param1 = min; fourth_st->iat_dist.param1 = min;
fourth_st->iat_dist.param2 = max; fourth_st->iat_dist.param2 = max;
fourth_st->start_usec = min; fourth_st->dist_added_shift_usec = min;
fourth_st->range_usec = max; fourth_st->dist_max_sample_usec = max;
circpad_state_t *fifth_st = &circ_client_machine.states[5]; circpad_state_t *fifth_st = &circ_client_machine.states[5];
fifth_st->next_state[CIRCPAD_EVENT_NONPADDING_RECV] = 6; fifth_st->next_state[CIRCPAD_EVENT_NONPADDING_RECV] = 6;
fifth_st->iat_dist.type = CIRCPAD_DIST_PARETO; fifth_st->iat_dist.type = CIRCPAD_DIST_PARETO;
fifth_st->iat_dist.param1 = min; fifth_st->iat_dist.param1 = min;
fifth_st->iat_dist.param2 = max; fifth_st->iat_dist.param2 = max;
fifth_st->start_usec = min; fifth_st->dist_added_shift_usec = min;
fifth_st->range_usec = max; fifth_st->dist_max_sample_usec = max;
} }
/** Simple test that the padding delays sampled from a uniform distribution /** Simple test that the padding delays sampled from a uniform distribution