[tor-commits] [tor/maint-0.3.1] relay: Change bandwidth stats interval to 24 hours

[nickm at torproject.org]

commit 8be50ca3ea90ac04b8a18c7d9a33f5ec3f3a6e28
Author: David Goulet <dgoulet at torproject.org>
Date:   Wed Nov 22 09:25:07 2017 -0500

    relay: Change bandwidth stats interval to 24 hours
    
    Going from 4 hours to 24 hours in order to try reduce the efficiency of guard
    discovery attacks.
    
    Closes #23856
    
    Signed-off-by: David Goulet <dgoulet at torproject.org>
---
 changes/ticket23856 | 4 ++++
 src/or/rephist.c    | 4 ++--
 src/or/router.c     | 2 +-
 3 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/changes/ticket23856 b/changes/ticket23856
new file mode 100644
index 000000000..049da18d0
--- /dev/null
+++ b/changes/ticket23856
@@ -0,0 +1,4 @@
+  o Minor feature (relay statistics): 
+    - Change relay bandwidth reporting stats interval from 4 hours to 24 hours
+      in order to reduce the efficiency of guard discovery attacks. Fixes
+      ticket 23856.
diff --git a/src/or/rephist.c b/src/or/rephist.c
index cedc56af0..5acc8f351 100644
--- a/src/or/rephist.c
+++ b/src/or/rephist.c
@@ -1131,9 +1131,9 @@ rep_hist_load_mtbf_data(time_t now)
  * totals? */
 #define NUM_SECS_ROLLING_MEASURE 10
 /** How large are the intervals for which we track and report bandwidth use? */
-#define NUM_SECS_BW_SUM_INTERVAL (4*60*60)
+#define NUM_SECS_BW_SUM_INTERVAL (24*60*60)
 /** How far in the past do we remember and publish bandwidth use? */
-#define NUM_SECS_BW_SUM_IS_VALID (24*60*60)
+#define NUM_SECS_BW_SUM_IS_VALID (5*24*60*60)
 /** How many bandwidth usage intervals do we remember? (derived) */
 #define NUM_TOTALS (NUM_SECS_BW_SUM_IS_VALID/NUM_SECS_BW_SUM_INTERVAL)
 
diff --git a/src/or/router.c b/src/or/router.c
index 90b2431a2..e1c2d20b3 100644
--- a/src/or/router.c
+++ b/src/or/router.c
@@ -2064,7 +2064,7 @@ mark_my_descriptor_dirty(const char *reason)
 
 /** How frequently will we republish our descriptor because of large (factor
  * of 2) shifts in estimated bandwidth? */
-#define MAX_BANDWIDTH_CHANGE_FREQ (20*60)
+#define MAX_BANDWIDTH_CHANGE_FREQ (3*60*60)
 
 /** Check whether bandwidth has changed a lot since the last time we announced
  * bandwidth. If so, mark our descriptor dirty. */