Merge remote-tracking branch 'public/ticket23856_025_01' into maint-0.2.5

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.

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)
 

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. */