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Merge remote-tracking branch 'public/bug6538'
Conflicts: configure.ac
This commit is contained in:
commit
75c9ccd4f8
16
changes/bug6538
Normal file
16
changes/bug6538
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@ -0,0 +1,16 @@
|
||||
o Minor bugfixes:
|
||||
- Switch weighted node selection rule from using a list of doubles
|
||||
to using a list of int64_t. This should make the process slightly
|
||||
easier to debug and maintain. Needed for fix for bug 6538.
|
||||
|
||||
o Security features:
|
||||
- Switch to a completely time-invariant approach for picking nodes
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||||
weighted by bandwidth. Our old approach would run through the
|
||||
part of the loop after it had made its choice slightly slower
|
||||
than it ran through the part of the loop before it had made its
|
||||
choice. Fix for bug 6538.
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o Code simplifications and refactoring:
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- Move the core of our "choose a weighted element at random" logic
|
||||
into its own function, and give it unit tests. Now the logic is
|
||||
testable, and a little less fragile too.
|
@ -303,6 +303,7 @@ AC_CHECK_FUNCS(
|
||||
inet_aton \
|
||||
ioctl \
|
||||
issetugid \
|
||||
llround \
|
||||
localtime_r \
|
||||
lround \
|
||||
memmem \
|
||||
|
@ -333,7 +333,7 @@ tor_mathlog(double d)
|
||||
}
|
||||
|
||||
/** Return the long integer closest to d. We define this wrapper here so
|
||||
* that not all users of math.h need to use the right incancations to get
|
||||
* that not all users of math.h need to use the right intancations to get
|
||||
* the c99 functions. */
|
||||
long
|
||||
tor_lround(double d)
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@ -347,6 +347,21 @@ tor_lround(double d)
|
||||
#endif
|
||||
}
|
||||
|
||||
/** Return the 64-bit integer closest to d. We define this wrapper here so
|
||||
* that not all users of math.h need to use the right incantations to get the
|
||||
* c99 functions. */
|
||||
int64_t
|
||||
tor_llround(double d)
|
||||
{
|
||||
#if defined(HAVE_LLROUND)
|
||||
return (int64_t)llround(d);
|
||||
#elif defined(HAVE_RINT)
|
||||
return (int64_t)rint(d);
|
||||
#else
|
||||
return (int64_t)(d > 0 ? d + 0.5 : ceil(d - 0.5));
|
||||
#endif
|
||||
}
|
||||
|
||||
/** Returns floor(log2(u64)). If u64 is 0, (incorrectly) returns 0. */
|
||||
int
|
||||
tor_log2(uint64_t u64)
|
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|
@ -160,6 +160,7 @@ void tor_log_mallinfo(int severity);
|
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/* Math functions */
|
||||
double tor_mathlog(double d) ATTR_CONST;
|
||||
long tor_lround(double d) ATTR_CONST;
|
||||
int64_t tor_llround(double d) ATTR_CONST;
|
||||
int tor_log2(uint64_t u64) ATTR_CONST;
|
||||
uint64_t round_to_power_of_2(uint64_t u64);
|
||||
unsigned round_to_next_multiple_of(unsigned number, unsigned divisor);
|
||||
|
@ -11,6 +11,7 @@
|
||||
* servers.
|
||||
**/
|
||||
|
||||
#define ROUTERLIST_PRIVATE
|
||||
#include "or.h"
|
||||
#include "circuitbuild.h"
|
||||
#include "config.h"
|
||||
@ -1647,6 +1648,92 @@ router_get_advertised_bandwidth_capped(const routerinfo_t *router)
|
||||
return result;
|
||||
}
|
||||
|
||||
/** Given an array of double/uint64_t unions that are currently being used as
|
||||
* doubles, convert them to uint64_t, and try to scale them linearly so as to
|
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* much of the range of uint64_t. If <b>total_out</b> is provided, set it to
|
||||
* the sum of all elements in the array _before_ scaling. */
|
||||
/* private */ void
|
||||
scale_array_elements_to_u64(u64_dbl_t *entries, int n_entries,
|
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uint64_t *total_out)
|
||||
{
|
||||
double total = 0.0;
|
||||
double scale_factor;
|
||||
int i;
|
||||
/* big, but far away from overflowing an int64_t */
|
||||
#define SCALE_TO_U64_MAX (INT64_MAX / 4)
|
||||
|
||||
for (i = 0; i < n_entries; ++i)
|
||||
total += entries[i].dbl;
|
||||
|
||||
scale_factor = SCALE_TO_U64_MAX / total;
|
||||
|
||||
for (i = 0; i < n_entries; ++i)
|
||||
entries[i].u64 = tor_llround(entries[i].dbl * scale_factor);
|
||||
|
||||
if (total_out)
|
||||
*total_out = (uint64_t) total;
|
||||
|
||||
#undef SCALE_TO_U64_MAX
|
||||
}
|
||||
|
||||
/** Time-invariant 64-bit greater-than; works on two integers in the range
|
||||
* (0,INT64_MAX). */
|
||||
#if SIZEOF_VOID_P == 8
|
||||
#define gt_i64_timei(a,b) ((a) > (b))
|
||||
#else
|
||||
static INLINE int
|
||||
gt_i64_timei(uint64_t a, uint64_t b)
|
||||
{
|
||||
int64_t diff = (int64_t) (b - a);
|
||||
int res = diff >> 63;
|
||||
return res & 1;
|
||||
}
|
||||
#endif
|
||||
|
||||
/** Pick a random element of <b>n_entries</b>-element array <b>entries</b>,
|
||||
* choosing each element with a probability proportional to its (uint64_t)
|
||||
* value, and return the index of that element. If all elements are 0, choose
|
||||
* an index at random. Return -1 on error.
|
||||
*/
|
||||
/* private */ int
|
||||
choose_array_element_by_weight(const u64_dbl_t *entries, int n_entries)
|
||||
{
|
||||
int i, i_chosen=-1, n_chosen=0;
|
||||
uint64_t total_so_far = 0;
|
||||
uint64_t rand_val;
|
||||
uint64_t total = 0;
|
||||
|
||||
for (i = 0; i < n_entries; ++i)
|
||||
total += entries[i].u64;
|
||||
|
||||
if (n_entries < 1)
|
||||
return -1;
|
||||
|
||||
if (total == 0)
|
||||
return crypto_rand_int(n_entries);
|
||||
|
||||
tor_assert(total < INT64_MAX);
|
||||
|
||||
rand_val = crypto_rand_uint64(total);
|
||||
|
||||
for (i = 0; i < n_entries; ++i) {
|
||||
total_so_far += entries[i].u64;
|
||||
if (gt_i64_timei(total_so_far, rand_val)) {
|
||||
i_chosen = i;
|
||||
n_chosen++;
|
||||
/* Set rand_val to INT64_MAX rather than stopping the loop. This way,
|
||||
* the time we spend in the loop does not leak which element we chose. */
|
||||
rand_val = INT64_MAX;
|
||||
}
|
||||
}
|
||||
tor_assert(total_so_far == total);
|
||||
tor_assert(n_chosen == 1);
|
||||
tor_assert(i_chosen >= 0);
|
||||
tor_assert(i_chosen < n_entries);
|
||||
|
||||
return i_chosen;
|
||||
}
|
||||
|
||||
/** When weighting bridges, enforce these values as lower and upper
|
||||
* bound for believable bandwidth, because there is no way for us
|
||||
* to verify a bridge's bandwidth currently. */
|
||||
@ -1697,16 +1784,10 @@ smartlist_choose_node_by_bandwidth_weights(smartlist_t *sl,
|
||||
bandwidth_weight_rule_t rule)
|
||||
{
|
||||
int64_t weight_scale;
|
||||
int64_t rand_bw;
|
||||
double Wg = -1, Wm = -1, We = -1, Wd = -1;
|
||||
double Wgb = -1, Wmb = -1, Web = -1, Wdb = -1;
|
||||
double weighted_bw = 0, unweighted_bw = 0;
|
||||
double *bandwidths;
|
||||
double tmp = 0;
|
||||
unsigned int i;
|
||||
unsigned int i_chosen;
|
||||
unsigned int i_has_been_chosen;
|
||||
int have_unknown = 0; /* true iff sl contains element not in consensus. */
|
||||
uint64_t weighted_bw = 0;
|
||||
u64_dbl_t *bandwidths;
|
||||
|
||||
/* Can't choose exit and guard at same time */
|
||||
tor_assert(rule == NO_WEIGHTING ||
|
||||
@ -1787,7 +1868,7 @@ smartlist_choose_node_by_bandwidth_weights(smartlist_t *sl,
|
||||
Web /= weight_scale;
|
||||
Wdb /= weight_scale;
|
||||
|
||||
bandwidths = tor_malloc_zero(sizeof(double)*smartlist_len(sl));
|
||||
bandwidths = tor_malloc_zero(sizeof(u64_dbl_t)*smartlist_len(sl));
|
||||
|
||||
// Cycle through smartlist and total the bandwidth.
|
||||
SMARTLIST_FOREACH_BEGIN(sl, const node_t *, node) {
|
||||
@ -1810,7 +1891,6 @@ smartlist_choose_node_by_bandwidth_weights(smartlist_t *sl,
|
||||
} else if (node->ri) {
|
||||
/* bridge or other descriptor not in our consensus */
|
||||
this_bw = bridge_get_advertised_bandwidth_bounded(node->ri);
|
||||
have_unknown = 1;
|
||||
} else {
|
||||
/* We can't use this one. */
|
||||
continue;
|
||||
@ -1826,72 +1906,32 @@ smartlist_choose_node_by_bandwidth_weights(smartlist_t *sl,
|
||||
} else { // middle
|
||||
weight = (is_dir ? Wmb*Wm : Wm);
|
||||
}
|
||||
/* These should be impossible; but overflows here would be bad, so let's
|
||||
* make sure. */
|
||||
if (this_bw < 0)
|
||||
this_bw = 0;
|
||||
if (weight < 0.0)
|
||||
weight = 0.0;
|
||||
|
||||
bandwidths[node_sl_idx] = weight*this_bw;
|
||||
weighted_bw += weight*this_bw;
|
||||
unweighted_bw += this_bw;
|
||||
bandwidths[node_sl_idx].dbl = weight*this_bw + 0.5;
|
||||
if (is_me)
|
||||
sl_last_weighted_bw_of_me = weight*this_bw;
|
||||
sl_last_weighted_bw_of_me = (uint64_t) bandwidths[node_sl_idx].dbl;
|
||||
} SMARTLIST_FOREACH_END(node);
|
||||
|
||||
/* XXXX this is a kludge to expose these values. */
|
||||
sl_last_total_weighted_bw = weighted_bw;
|
||||
|
||||
log_debug(LD_CIRC, "Choosing node for rule %s based on weights "
|
||||
"Wg=%f Wm=%f We=%f Wd=%f with total bw %f",
|
||||
"Wg=%f Wm=%f We=%f Wd=%f with total bw "U64_FORMAT,
|
||||
bandwidth_weight_rule_to_string(rule),
|
||||
Wg, Wm, We, Wd, weighted_bw);
|
||||
Wg, Wm, We, Wd, U64_PRINTF_ARG(weighted_bw));
|
||||
|
||||
/* If there is no bandwidth, choose at random */
|
||||
if (DBL_TO_U64(weighted_bw) == 0) {
|
||||
/* Don't warn when using bridges/relays not in the consensus */
|
||||
if (!have_unknown) {
|
||||
#define ZERO_BANDWIDTH_WARNING_INTERVAL (15)
|
||||
static ratelim_t zero_bandwidth_warning_limit =
|
||||
RATELIM_INIT(ZERO_BANDWIDTH_WARNING_INTERVAL);
|
||||
char *msg;
|
||||
if ((msg = rate_limit_log(&zero_bandwidth_warning_limit,
|
||||
approx_time()))) {
|
||||
log_warn(LD_CIRC,
|
||||
"Weighted bandwidth is %f in node selection for rule %s "
|
||||
"(unweighted was %f) %s",
|
||||
weighted_bw, bandwidth_weight_rule_to_string(rule),
|
||||
unweighted_bw, msg);
|
||||
}
|
||||
}
|
||||
scale_array_elements_to_u64(bandwidths, smartlist_len(sl),
|
||||
&sl_last_total_weighted_bw);
|
||||
|
||||
{
|
||||
int idx = choose_array_element_by_weight(bandwidths,
|
||||
smartlist_len(sl));
|
||||
tor_free(bandwidths);
|
||||
return smartlist_choose(sl);
|
||||
return idx < 0 ? NULL : smartlist_get(sl, idx);
|
||||
}
|
||||
|
||||
rand_bw = crypto_rand_uint64(DBL_TO_U64(weighted_bw));
|
||||
rand_bw++; /* crypto_rand_uint64() counts from 0, and we need to count
|
||||
* from 1 below. See bug 1203 for details. */
|
||||
|
||||
/* Last, count through sl until we get to the element we picked */
|
||||
i_chosen = (unsigned)smartlist_len(sl);
|
||||
i_has_been_chosen = 0;
|
||||
tmp = 0.0;
|
||||
for (i=0; i < (unsigned)smartlist_len(sl); i++) {
|
||||
tmp += bandwidths[i];
|
||||
if (tmp >= rand_bw && !i_has_been_chosen) {
|
||||
i_chosen = i;
|
||||
i_has_been_chosen = 1;
|
||||
}
|
||||
}
|
||||
i = i_chosen;
|
||||
|
||||
if (i == (unsigned)smartlist_len(sl)) {
|
||||
/* This was once possible due to round-off error, but shouldn't be able
|
||||
* to occur any longer. */
|
||||
tor_fragile_assert();
|
||||
--i;
|
||||
log_warn(LD_BUG, "Round-off error in computing bandwidth had an effect on "
|
||||
" which router we chose. Please tell the developers. "
|
||||
"%f " U64_FORMAT " %f", tmp, U64_PRINTF_ARG(rand_bw),
|
||||
weighted_bw);
|
||||
}
|
||||
tor_free(bandwidths);
|
||||
return smartlist_get(sl, i);
|
||||
}
|
||||
|
||||
/** Helper function:
|
||||
@ -1912,17 +1952,16 @@ smartlist_choose_node_by_bandwidth(smartlist_t *sl,
|
||||
bandwidth_weight_rule_t rule)
|
||||
{
|
||||
unsigned int i;
|
||||
unsigned int i_chosen;
|
||||
unsigned int i_has_been_chosen;
|
||||
int32_t *bandwidths;
|
||||
u64_dbl_t *bandwidths;
|
||||
int is_exit;
|
||||
int is_guard;
|
||||
uint64_t total_nonexit_bw = 0, total_exit_bw = 0, total_bw = 0;
|
||||
uint64_t total_nonguard_bw = 0, total_guard_bw = 0;
|
||||
uint64_t rand_bw, tmp;
|
||||
int is_fast;
|
||||
double total_nonexit_bw = 0, total_exit_bw = 0;
|
||||
double total_nonguard_bw = 0, total_guard_bw = 0;
|
||||
double exit_weight;
|
||||
double guard_weight;
|
||||
int n_unknown = 0;
|
||||
bitarray_t *fast_bits;
|
||||
bitarray_t *exit_bits;
|
||||
bitarray_t *guard_bits;
|
||||
int me_idx = -1;
|
||||
@ -1946,10 +1985,9 @@ smartlist_choose_node_by_bandwidth(smartlist_t *sl,
|
||||
}
|
||||
|
||||
/* First count the total bandwidth weight, and make a list
|
||||
* of each value. <0 means "unknown; no routerinfo." We use the
|
||||
* bits of negative values to remember whether the router was fast (-x)&1
|
||||
* and whether it was an exit (-x)&2 or guard (-x)&4. Yes, it's a hack. */
|
||||
bandwidths = tor_malloc(sizeof(int32_t)*smartlist_len(sl));
|
||||
* of each value. We use UINT64_MAX to indicate "unknown". */
|
||||
bandwidths = tor_malloc_zero(sizeof(u64_dbl_t)*smartlist_len(sl));
|
||||
fast_bits = bitarray_init_zero(smartlist_len(sl));
|
||||
exit_bits = bitarray_init_zero(smartlist_len(sl));
|
||||
guard_bits = bitarray_init_zero(smartlist_len(sl));
|
||||
|
||||
@ -1957,7 +1995,6 @@ smartlist_choose_node_by_bandwidth(smartlist_t *sl,
|
||||
SMARTLIST_FOREACH_BEGIN(sl, const node_t *, node) {
|
||||
/* first, learn what bandwidth we think i has */
|
||||
int is_known = 1;
|
||||
int32_t flags = 0;
|
||||
uint32_t this_bw = 0;
|
||||
i = node_sl_idx;
|
||||
|
||||
@ -1970,12 +2007,7 @@ smartlist_choose_node_by_bandwidth(smartlist_t *sl,
|
||||
if (node->rs->has_bandwidth) {
|
||||
this_bw = kb_to_bytes(node->rs->bandwidth);
|
||||
} else { /* guess */
|
||||
/* XXX024 once consensuses always list bandwidths, we can take
|
||||
* this guessing business out. -RD */
|
||||
is_known = 0;
|
||||
flags = node->rs->is_fast ? 1 : 0;
|
||||
flags |= is_exit ? 2 : 0;
|
||||
flags |= is_guard ? 4 : 0;
|
||||
}
|
||||
} else if (node->ri) {
|
||||
/* Must be a bridge if we're willing to use it */
|
||||
@ -1986,12 +2018,11 @@ smartlist_choose_node_by_bandwidth(smartlist_t *sl,
|
||||
bitarray_set(exit_bits, i);
|
||||
if (is_guard)
|
||||
bitarray_set(guard_bits, i);
|
||||
if (node->is_fast)
|
||||
bitarray_set(fast_bits, i);
|
||||
|
||||
if (is_known) {
|
||||
bandwidths[i] = (int32_t) this_bw;
|
||||
/* Casting this_bw to int32_t is safe because both kb_to_bytes
|
||||
and bridge_get_advertised_bandwidth_bounded limit it to below
|
||||
INT32_MAX. */
|
||||
tor_assert(bandwidths[i] >= 0);
|
||||
bandwidths[i].dbl = this_bw;
|
||||
if (is_guard)
|
||||
total_guard_bw += this_bw;
|
||||
else
|
||||
@ -2002,14 +2033,16 @@ smartlist_choose_node_by_bandwidth(smartlist_t *sl,
|
||||
total_nonexit_bw += this_bw;
|
||||
} else {
|
||||
++n_unknown;
|
||||
bandwidths[node_sl_idx] = -flags;
|
||||
bandwidths[i].dbl = -1.0;
|
||||
}
|
||||
} SMARTLIST_FOREACH_END(node);
|
||||
|
||||
#define EPSILON .1
|
||||
|
||||
/* Now, fill in the unknown values. */
|
||||
if (n_unknown) {
|
||||
int32_t avg_fast, avg_slow;
|
||||
if (total_exit_bw+total_nonexit_bw) {
|
||||
if (total_exit_bw+total_nonexit_bw < EPSILON) {
|
||||
/* if there's some bandwidth, there's at least one known router,
|
||||
* so no worries about div by 0 here */
|
||||
int n_known = smartlist_len(sl)-n_unknown;
|
||||
@ -2020,26 +2053,27 @@ smartlist_choose_node_by_bandwidth(smartlist_t *sl,
|
||||
avg_slow = 20000;
|
||||
}
|
||||
for (i=0; i<(unsigned)smartlist_len(sl); ++i) {
|
||||
int32_t bw = bandwidths[i];
|
||||
if (bw>=0)
|
||||
if (bandwidths[i].dbl >= 0.0)
|
||||
continue;
|
||||
is_exit = ((-bw)&2);
|
||||
is_guard = ((-bw)&4);
|
||||
bandwidths[i] = ((-bw)&1) ? avg_fast : avg_slow;
|
||||
is_fast = bitarray_is_set(fast_bits, i);
|
||||
is_exit = bitarray_is_set(exit_bits, i);
|
||||
is_guard = bitarray_is_set(guard_bits, i);
|
||||
bandwidths[i].dbl = is_fast ? avg_fast : avg_slow;
|
||||
if (is_exit)
|
||||
total_exit_bw += bandwidths[i];
|
||||
total_exit_bw += bandwidths[i].dbl;
|
||||
else
|
||||
total_nonexit_bw += bandwidths[i];
|
||||
total_nonexit_bw += bandwidths[i].dbl;
|
||||
if (is_guard)
|
||||
total_guard_bw += bandwidths[i];
|
||||
total_guard_bw += bandwidths[i].dbl;
|
||||
else
|
||||
total_nonguard_bw += bandwidths[i];
|
||||
total_nonguard_bw += bandwidths[i].dbl;
|
||||
}
|
||||
}
|
||||
|
||||
/* If there's no bandwidth at all, pick at random. */
|
||||
if (!(total_exit_bw+total_nonexit_bw)) {
|
||||
if (total_exit_bw+total_nonexit_bw < EPSILON) {
|
||||
tor_free(bandwidths);
|
||||
tor_free(fast_bits);
|
||||
tor_free(exit_bits);
|
||||
tor_free(guard_bits);
|
||||
return smartlist_choose(sl);
|
||||
@ -2054,12 +2088,12 @@ smartlist_choose_node_by_bandwidth(smartlist_t *sl,
|
||||
* For detailed derivation of this formula, see
|
||||
* http://archives.seul.org/or/dev/Jul-2007/msg00056.html
|
||||
*/
|
||||
if (rule == WEIGHT_FOR_EXIT || !total_exit_bw)
|
||||
if (rule == WEIGHT_FOR_EXIT || total_exit_bw<EPSILON)
|
||||
exit_weight = 1.0;
|
||||
else
|
||||
exit_weight = 1.0 - all_bw/(3.0*exit_bw);
|
||||
|
||||
if (rule == WEIGHT_FOR_GUARD || !total_guard_bw)
|
||||
if (rule == WEIGHT_FOR_GUARD || total_guard_bw<EPSILON)
|
||||
guard_weight = 1.0;
|
||||
else
|
||||
guard_weight = 1.0 - all_bw/(3.0*guard_bw);
|
||||
@ -2070,29 +2104,25 @@ smartlist_choose_node_by_bandwidth(smartlist_t *sl,
|
||||
if (guard_weight <= 0.0)
|
||||
guard_weight = 0.0;
|
||||
|
||||
total_bw = 0;
|
||||
sl_last_weighted_bw_of_me = 0;
|
||||
for (i=0; i < (unsigned)smartlist_len(sl); i++) {
|
||||
uint64_t bw;
|
||||
tor_assert(bandwidths[i].dbl >= 0.0);
|
||||
|
||||
is_exit = bitarray_is_set(exit_bits, i);
|
||||
is_guard = bitarray_is_set(guard_bits, i);
|
||||
if (is_exit && is_guard)
|
||||
bw = ((uint64_t)(bandwidths[i] * exit_weight * guard_weight));
|
||||
bandwidths[i].dbl *= exit_weight * guard_weight;
|
||||
else if (is_guard)
|
||||
bw = ((uint64_t)(bandwidths[i] * guard_weight));
|
||||
bandwidths[i].dbl *= guard_weight;
|
||||
else if (is_exit)
|
||||
bw = ((uint64_t)(bandwidths[i] * exit_weight));
|
||||
else
|
||||
bw = bandwidths[i];
|
||||
total_bw += bw;
|
||||
bandwidths[i].dbl *= exit_weight;
|
||||
|
||||
if (i == (unsigned) me_idx)
|
||||
sl_last_weighted_bw_of_me = bw;
|
||||
sl_last_weighted_bw_of_me = (uint64_t) bandwidths[i].dbl;
|
||||
}
|
||||
}
|
||||
|
||||
/* XXXX this is a kludge to expose these values. */
|
||||
sl_last_total_weighted_bw = total_bw;
|
||||
|
||||
#if 0
|
||||
log_debug(LD_CIRC, "Total weighted bw = "U64_FORMAT
|
||||
", exit bw = "U64_FORMAT
|
||||
", nonexit bw = "U64_FORMAT", exit weight = %f "
|
||||
@ -2105,50 +2135,20 @@ smartlist_choose_node_by_bandwidth(smartlist_t *sl,
|
||||
exit_weight, (int)(rule == WEIGHT_FOR_EXIT),
|
||||
U64_PRINTF_ARG(total_guard_bw), U64_PRINTF_ARG(total_nonguard_bw),
|
||||
guard_weight, (int)(rule == WEIGHT_FOR_GUARD));
|
||||
#endif
|
||||
|
||||
/* Almost done: choose a random value from the bandwidth weights. */
|
||||
rand_bw = crypto_rand_uint64(total_bw);
|
||||
rand_bw++; /* crypto_rand_uint64() counts from 0, and we need to count
|
||||
* from 1 below. See bug 1203 for details. */
|
||||
scale_array_elements_to_u64(bandwidths, smartlist_len(sl),
|
||||
&sl_last_total_weighted_bw);
|
||||
|
||||
/* Last, count through sl until we get to the element we picked */
|
||||
tmp = 0;
|
||||
i_chosen = (unsigned)smartlist_len(sl);
|
||||
i_has_been_chosen = 0;
|
||||
for (i=0; i < (unsigned)smartlist_len(sl); i++) {
|
||||
is_exit = bitarray_is_set(exit_bits, i);
|
||||
is_guard = bitarray_is_set(guard_bits, i);
|
||||
|
||||
/* Weights can be 0 if not counting guards/exits */
|
||||
if (is_exit && is_guard)
|
||||
tmp += ((uint64_t)(bandwidths[i] * exit_weight * guard_weight));
|
||||
else if (is_guard)
|
||||
tmp += ((uint64_t)(bandwidths[i] * guard_weight));
|
||||
else if (is_exit)
|
||||
tmp += ((uint64_t)(bandwidths[i] * exit_weight));
|
||||
else
|
||||
tmp += bandwidths[i];
|
||||
|
||||
if (tmp >= rand_bw && !i_has_been_chosen) {
|
||||
i_chosen = i;
|
||||
i_has_been_chosen = 1;
|
||||
}
|
||||
{
|
||||
int idx = choose_array_element_by_weight(bandwidths,
|
||||
smartlist_len(sl));
|
||||
tor_free(bandwidths);
|
||||
tor_free(fast_bits);
|
||||
tor_free(exit_bits);
|
||||
tor_free(guard_bits);
|
||||
return idx < 0 ? NULL : smartlist_get(sl, idx);
|
||||
}
|
||||
i = i_chosen;
|
||||
if (i == (unsigned)smartlist_len(sl)) {
|
||||
/* This was once possible due to round-off error, but shouldn't be able
|
||||
* to occur any longer. */
|
||||
tor_fragile_assert();
|
||||
--i;
|
||||
log_warn(LD_BUG, "Round-off error in computing bandwidth had an effect on "
|
||||
" which router we chose. Please tell the developers. "
|
||||
U64_FORMAT " " U64_FORMAT " " U64_FORMAT, U64_PRINTF_ARG(tmp),
|
||||
U64_PRINTF_ARG(rand_bw), U64_PRINTF_ARG(total_bw));
|
||||
}
|
||||
tor_free(bandwidths);
|
||||
tor_free(exit_bits);
|
||||
tor_free(guard_bits);
|
||||
return smartlist_get(sl, i);
|
||||
}
|
||||
|
||||
/** Choose a random element of status list <b>sl</b>, weighted by
|
||||
|
@ -216,5 +216,19 @@ int hex_digest_nickname_decode(const char *hexdigest,
|
||||
char *nickname_qualifier_out,
|
||||
char *nickname_out);
|
||||
|
||||
#ifdef ROUTERLIST_PRIVATE
|
||||
/** Helper type for choosing routers by bandwidth: contains a union of
|
||||
* double and uint64_t. Before we call scale_array_elements_to_u64, it holds
|
||||
* a double; after, it holds a uint64_t. */
|
||||
typedef union u64_dbl_t {
|
||||
uint64_t u64;
|
||||
double dbl;
|
||||
} u64_dbl_t;
|
||||
|
||||
int choose_array_element_by_weight(const u64_dbl_t *entries, int n_entries);
|
||||
void scale_array_elements_to_u64(u64_dbl_t *entries, int n_entries,
|
||||
uint64_t *total_out);
|
||||
#endif
|
||||
|
||||
#endif
|
||||
|
||||
|
@ -65,6 +65,10 @@
|
||||
|
||||
#define test_memeq_hex(expr1, hex) test_mem_op_hex(expr1, ==, hex)
|
||||
|
||||
#define tt_double_op(a,op,b) \
|
||||
tt_assert_test_type(a,b,#a" "#op" "#b,double,(val1_ op val2_),"%f", \
|
||||
TT_EXIT_TEST_FUNCTION)
|
||||
|
||||
const char *get_fname(const char *name);
|
||||
crypto_pk_t *pk_generate(int idx);
|
||||
|
||||
|
@ -4,9 +4,12 @@
|
||||
/* See LICENSE for licensing information */
|
||||
|
||||
#include "orconfig.h"
|
||||
#include <math.h>
|
||||
|
||||
#define DIRSERV_PRIVATE
|
||||
#define DIRVOTE_PRIVATE
|
||||
#define ROUTER_PRIVATE
|
||||
#define ROUTERLIST_PRIVATE
|
||||
#define HIBERNATE_PRIVATE
|
||||
#include "or.h"
|
||||
#include "directory.h"
|
||||
@ -1389,6 +1392,124 @@ test_dir_v3_networkstatus(void)
|
||||
ns_detached_signatures_free(dsig2);
|
||||
}
|
||||
|
||||
static void
|
||||
test_dir_scale_bw(void *testdata)
|
||||
{
|
||||
double v[8] = { 2.0/3,
|
||||
7.0,
|
||||
1.0,
|
||||
3.0,
|
||||
1.0/5,
|
||||
1.0/7,
|
||||
12.0,
|
||||
24.0 };
|
||||
u64_dbl_t vals[8];
|
||||
uint64_t total;
|
||||
int i;
|
||||
|
||||
(void) testdata;
|
||||
|
||||
for (i=0; i<8; ++i)
|
||||
vals[i].dbl = v[i];
|
||||
|
||||
scale_array_elements_to_u64(vals, 8, &total);
|
||||
|
||||
tt_int_op((int)total, ==, 48);
|
||||
total = 0;
|
||||
for (i=0; i<8; ++i) {
|
||||
total += vals[i].u64;
|
||||
}
|
||||
tt_assert(total >= (U64_LITERAL(1)<<60));
|
||||
tt_assert(total <= (U64_LITERAL(1)<<62));
|
||||
|
||||
for (i=0; i<8; ++i) {
|
||||
double ratio = ((double)vals[i].u64) / vals[2].u64;
|
||||
tt_double_op(fabs(ratio - v[i]), <, .00001);
|
||||
}
|
||||
|
||||
done:
|
||||
;
|
||||
}
|
||||
|
||||
static void
|
||||
test_dir_random_weighted(void *testdata)
|
||||
{
|
||||
int histogram[10];
|
||||
uint64_t vals[10] = {3,1,2,4,6,0,7,5,8,9}, total=0;
|
||||
u64_dbl_t inp[10];
|
||||
int i, choice;
|
||||
const int n = 50000;
|
||||
double max_sq_error;
|
||||
(void) testdata;
|
||||
|
||||
/* Try a ten-element array with values from 0 through 10. The values are
|
||||
* in a scrambled order to make sure we don't depend on order. */
|
||||
memset(histogram,0,sizeof(histogram));
|
||||
for (i=0; i<10; ++i) {
|
||||
inp[i].u64 = vals[i];
|
||||
total += vals[i];
|
||||
}
|
||||
tt_int_op(total, ==, 45);
|
||||
for (i=0; i<n; ++i) {
|
||||
choice = choose_array_element_by_weight(inp, 10);
|
||||
tt_int_op(choice, >=, 0);
|
||||
tt_int_op(choice, <, 10);
|
||||
histogram[choice]++;
|
||||
}
|
||||
|
||||
/* Now see if we chose things about frequently enough. */
|
||||
max_sq_error = 0;
|
||||
for (i=0; i<10; ++i) {
|
||||
int expected = (int)(n*vals[i]/total);
|
||||
double frac_diff = 0, sq;
|
||||
TT_BLATHER((" %d : %5d vs %5d\n", (int)vals[i], histogram[i], expected));
|
||||
if (expected)
|
||||
frac_diff = (histogram[i] - expected) / ((double)expected);
|
||||
else
|
||||
tt_int_op(histogram[i], ==, 0);
|
||||
|
||||
sq = frac_diff * frac_diff;
|
||||
if (sq > max_sq_error)
|
||||
max_sq_error = sq;
|
||||
}
|
||||
/* It should almost always be much much less than this. If you want to
|
||||
* figure out the odds, please feel free. */
|
||||
tt_double_op(max_sq_error, <, .05);
|
||||
|
||||
/* Now try a singleton; do we choose it? */
|
||||
for (i = 0; i < 100; ++i) {
|
||||
choice = choose_array_element_by_weight(inp, 1);
|
||||
tt_int_op(choice, ==, 0);
|
||||
}
|
||||
|
||||
/* Now try an array of zeros. We should choose randomly. */
|
||||
memset(histogram,0,sizeof(histogram));
|
||||
for (i = 0; i < 5; ++i)
|
||||
inp[i].u64 = 0;
|
||||
for (i = 0; i < n; ++i) {
|
||||
choice = choose_array_element_by_weight(inp, 5);
|
||||
tt_int_op(choice, >=, 0);
|
||||
tt_int_op(choice, <, 5);
|
||||
histogram[choice]++;
|
||||
}
|
||||
/* Now see if we chose things about frequently enough. */
|
||||
max_sq_error = 0;
|
||||
for (i=0; i<5; ++i) {
|
||||
int expected = n/5;
|
||||
double frac_diff = 0, sq;
|
||||
TT_BLATHER((" %d : %5d vs %5d\n", (int)vals[i], histogram[i], expected));
|
||||
frac_diff = (histogram[i] - expected) / ((double)expected);
|
||||
sq = frac_diff * frac_diff;
|
||||
if (sq > max_sq_error)
|
||||
max_sq_error = sq;
|
||||
}
|
||||
/* It should almost always be much much less than this. If you want to
|
||||
* figure out the odds, please feel free. */
|
||||
tt_double_op(max_sq_error, <, .05);
|
||||
done:
|
||||
;
|
||||
}
|
||||
|
||||
#define DIR_LEGACY(name) \
|
||||
{ #name, legacy_test_helper, TT_FORK, &legacy_setup, test_dir_ ## name }
|
||||
|
||||
@ -1404,6 +1525,8 @@ struct testcase_t dir_tests[] = {
|
||||
DIR_LEGACY(measured_bw),
|
||||
DIR_LEGACY(param_voting),
|
||||
DIR_LEGACY(v3_networkstatus),
|
||||
DIR(random_weighted),
|
||||
DIR(scale_bw),
|
||||
END_OF_TESTCASES
|
||||
};
|
||||
|
||||
|
Loading…
Reference in New Issue
Block a user