[tor-commits] [tor/master] Ignore advertised bandwidths if we have enough measured bandwidths available
nickm at torproject.org
nickm at torproject.org
Mon Mar 18 19:19:01 UTC 2013
commit f93f7e331be94114d82c17108e741eb2482e6bda
Author: Andrea Shepard <andrea at torproject.org>
Date: Mon Mar 18 11:15:21 2013 -0700
Ignore advertised bandwidths if we have enough measured bandwidths available
---
changes/bug8435 | 4 ++
src/or/config.c | 1 +
src/or/dirserv.c | 97 ++++++++++++++++++++++++++++++++++++++++++++++++++----
src/or/or.h | 4 ++
4 files changed, 99 insertions(+), 7 deletions(-)
diff --git a/changes/bug8435 b/changes/bug8435
new file mode 100644
index 0000000..da7ca7c
--- /dev/null
+++ b/changes/bug8435
@@ -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.
diff --git a/src/or/config.c b/src/or/config.c
index f888426..f3e4083 100644
--- a/src/or/config.c
+++ b/src/or/config.c
@@ -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"),
diff --git a/src/or/dirserv.c b/src/or/dirserv.c
index 37934a0..c769bed 100644
--- a/src/or/dirserv.c
+++ b/src/or/dirserv.c
@@ -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);
diff --git a/src/or/or.h b/src/or/or.h
index 45eb467..f2605d6 100644
--- a/src/or/or.h
+++ b/src/or/or.h
@@ -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;
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