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Ignore advertised bandwidths if we have enough measured bandwidths available

This commit is contained in:
Andrea Shepard 2013-03-18 11:15:21 -07:00
parent 8027ebb5fd
commit f93f7e331b
4 changed files with 99 additions and 7 deletions
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4
changes/bug8435 Normal file
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@ -0,0 +1,4 @@
o Major bugfixes:
- When dirserv.c computes flags and thresholds, ignore advertised
bandwidths if we have more than a threshold number of routers with
measured bandwidths.

1
src/or/config.c
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@ -299,6 +299,7 @@ static config_var_t option_vars_[] = {
V(MaxClientCircuitsPending, UINT, "32"),
OBSOLETE("MaxOnionsPending"),
V(MaxOnionQueueDelay, MSEC_INTERVAL, "1750 msec"),
V(MinMeasuredBWsForAuthToIgnoreAdvertised, INT, "500"),
OBSOLETE("MonthlyAccountingStart"),
V(MyFamily, STRING, NULL),
V(NewCircuitPeriod, INTERVAL, "30 seconds"),

97
src/or/dirserv.c
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@ -66,6 +66,9 @@ static cached_dir_t *the_directory = NULL;
/** For authoritative directories: the current (v1) network status. */
static cached_dir_t the_runningrouters;
/** Total number of routers with measured bandwidth */
static int routers_with_measured_bw = 0;
static void directory_remove_invalid(void);
static cached_dir_t *dirserv_regenerate_directory(void);
static char *format_versions_list(config_line_t *ln);
@ -86,6 +89,7 @@ static const signed_descriptor_t *get_signed_descriptor_by_fp(
static was_router_added_t dirserv_add_extrainfo(extrainfo_t *ei,
const char **msg);
static uint32_t dirserv_get_bandwidth_for_router(const routerinfo_t *ri);
static uint32_t dirserv_get_credible_bandwidth(const routerinfo_t *ri);
/************** Fingerprint handling code ************/
@ -1877,12 +1881,18 @@ dirserv_thinks_router_is_hs_dir(const routerinfo_t *router,
* include a router in our calculations, and return true iff we should. */
static int
router_counts_toward_thresholds(const node_t *node, time_t now,
const digestmap_t *omit_as_sybil)
const digestmap_t *omit_as_sybil,
int require_mbw)
{
/* Have measured bw? */
int have_mbw =
dirserv_query_measured_bw_cache(node->ri->cache_info.identity_digest,
NULL, NULL);
return node->ri && router_is_active(node->ri, node, now) &&
!digestmap_get(omit_as_sybil, node->ri->cache_info.identity_digest) &&
(dirserv_get_bandwidth_for_router(node->ri) >=
ABSOLUTE_MIN_BW_VALUE_TO_CONSIDER);
(dirserv_get_credible_bandwidth(node->ri) >=
ABSOLUTE_MIN_BW_VALUE_TO_CONSIDER) && (have_mbw || !require_mbw);
}
/** Look through the routerlist, the Mean Time Between Failure history, and
@ -1904,6 +1914,11 @@ dirserv_compute_performance_thresholds(routerlist_t *rl,
time_t now = time(NULL);
const or_options_t *options = get_options();
/* Require mbw? */
int require_mbw =
(routers_with_measured_bw >
options->MinMeasuredBWsForAuthToIgnoreAdvertised) ? 1 : 0;
/* initialize these all here, in case there are no routers */
stable_uptime = 0;
stable_mtbf = 0;
@ -1936,7 +1951,8 @@ dirserv_compute_performance_thresholds(routerlist_t *rl,
/* Now, fill in the arrays. */
SMARTLIST_FOREACH_BEGIN(nodelist_get_list(), node_t *, node) {
if (router_counts_toward_thresholds(node, now, omit_as_sybil)) {
if (router_counts_toward_thresholds(node, now, omit_as_sybil,
require_mbw)) {
routerinfo_t *ri = node->ri;
const char *id = ri->cache_info.identity_digest;
uint32_t bw;
@ -1945,7 +1961,7 @@ dirserv_compute_performance_thresholds(routerlist_t *rl,
uptimes[n_active] = (uint32_t)real_uptime(ri, now);
mtbfs[n_active] = rep_hist_get_stability(id, now);
tks [n_active] = rep_hist_get_weighted_time_known(id, now);
bandwidths[n_active] = bw = dirserv_get_bandwidth_for_router(ri);
bandwidths[n_active] = bw = dirserv_get_credible_bandwidth(ri);
total_bandwidth += bw;
if (node->is_exit && !node->is_bad_exit) {
total_exit_bandwidth += bw;
@ -2001,7 +2017,8 @@ dirserv_compute_performance_thresholds(routerlist_t *rl,
n_familiar = 0;
SMARTLIST_FOREACH_BEGIN(nodelist_get_list(), node_t *, node) {
if (router_counts_toward_thresholds(node, now, omit_as_sybil)) {
if (router_counts_toward_thresholds(node, now,
omit_as_sybil, require_mbw)) {
routerinfo_t *ri = node->ri;
const char *id = ri->cache_info.identity_digest;
long tk = rep_hist_get_weighted_time_known(id, now);
@ -2182,6 +2199,59 @@ dirserv_get_bandwidth_for_router(const routerinfo_t *ri)
return bw;
}
/** Look through the routerlist, and using the measured bandwidth cache count
* how many measured bandwidths we know. This is used to decide whether we
* ever trust advertised bandwidths for purposes of assigning flags. */
static void
dirserv_count_measured_bws(routerlist_t *rl)
{
/* Initialize this first */
routers_with_measured_bw = 0;
tor_assert(rl);
tor_assert(rl->routers);
/* Iterate over the routerlist and count measured bandwidths */
SMARTLIST_FOREACH_BEGIN(rl->routers, routerinfo_t *, ri) {
/* Check if we know a measured bandwidth for this one */
if (dirserv_query_measured_bw_cache(ri->cache_info.identity_digest,
NULL, NULL)) {
++routers_with_measured_bw;
}
} SMARTLIST_FOREACH_END(ri);
}
/** Return the bandwidth we believe for assigning flags; prefer measured
* over advertised, and if we have above a threshold quantity of measured
* bandwidths, we don't want to ever give flags to unmeasured routers, so
* return 0. */
static uint32_t
dirserv_get_credible_bandwidth(const routerinfo_t *ri)
{
int threshold;
uint32_t bw = 0;
long mbw;
tor_assert(ri);
/* Check if we have a measured bandwidth, and check the threshold if not */
if (!(dirserv_query_measured_bw_cache(ri->cache_info.identity_digest,
&mbw, NULL))) {
threshold = get_options()->MinMeasuredBWsForAuthToIgnoreAdvertised;
if (routers_with_measured_bw > threshold) {
/* Return zero for unmeasured bandwidth if we are above threshold */
bw = 0;
} else {
/* Return an advertised bandwidth otherwise */
bw = router_get_advertised_bandwidth(ri);
}
} else {
/* We have the measured bandwidth in mbw */
bw = (uint32_t)mbw;
}
return bw;
}
/** Give a statement of our current performance thresholds for inclusion
* in a vote document. */
char *
@ -2604,7 +2674,7 @@ set_routerstatus_from_routerinfo(routerstatus_t *rs,
int listbaddirs, int vote_on_hsdirs)
{
const or_options_t *options = get_options();
uint32_t routerbw = dirserv_get_bandwidth_for_router(ri);
uint32_t routerbw = dirserv_get_credible_bandwidth(ri);
memset(rs, 0, sizeof(routerstatus_t));
@ -2927,6 +2997,14 @@ dirserv_generate_networkstatus_vote_obj(crypto_pk_t *private_key,
*/
if (options->V3BandwidthsFile) {
dirserv_read_measured_bandwidths(options->V3BandwidthsFile, NULL);
} else {
/*
* No bandwidths file; clear the measured bandwidth cache in case we had
* one last time around.
*/
if (dirserv_get_measured_bw_cache_size() > 0) {
dirserv_clear_measured_bw_cache();
}
}
/* precompute this part, since we need it to decide what "stable"
@ -2945,6 +3023,10 @@ dirserv_generate_networkstatus_vote_obj(crypto_pk_t *private_key,
rep_hist_make_router_pessimal(sybil_id, now);
} DIGESTMAP_FOREACH_END;
/* Count how many have measured bandwidths so we know how to assign flags;
* this must come before dirserv_compute_performance_thresholds() */
dirserv_count_measured_bws(rl);
dirserv_compute_performance_thresholds(rl, omit_as_sybil);
routerstatuses = smartlist_new();
@ -2989,6 +3071,7 @@ dirserv_generate_networkstatus_vote_obj(crypto_pk_t *private_key,
smartlist_free(routers);
digestmap_free(omit_as_sybil, NULL);
/* This pass through applies the measured bw lines to the routerstatuses */
if (options->V3BandwidthsFile) {
dirserv_read_measured_bandwidths(options->V3BandwidthsFile,
routerstatuses);

4
src/or/or.h
View File

@ -3870,6 +3870,10 @@ typedef struct {
* consensus vote on the 'params' line. */
char *ConsensusParams;
/** Authority only: minimum number of measured bandwidths we must see
* before we only beliee measured bandwidths to assign flags. */
int MinMeasuredBWsForAuthToIgnoreAdvertised;
/** The length of time that we think an initial consensus should be fresh.
* Only altered on testing networks. */
int TestingV3AuthInitialVotingInterval;