Commit 7cca6dc1 authored by Roger Dingledine's avatar Roger Dingledine
Browse files

don't build preemptive conflux circuits if no predicted ports 

Conflux circuit building was ignoring the "predicted ports" feature,
which aims to make Tor stop building circuits if there have been
no user requests lately. This bug led to every idle Tor on the
network building and discarding circuits every 30 seconds, which
added overall load to the network, used bandwidth and battery from
clients that weren't actively using their Tor, and kept sockets open
on guards which added connection padding essentially forever.

Bug went in on commit 39c2927d when we added preemptive conflux circuit
pools.

Fixes bug 40981; bugfix on 0.4.8.1-alpha.
parent 6feaea8f

changes/bug40981

0 → 100644
+9 −0
Original line number Diff line number Diff line 
  o Major bugfixes (circuit building):

    - Conflux circuit building was ignoring the "predicted ports" feature,

      which aims to make Tor stop building circuits if there have been

      no user requests lately. This bug led to every idle Tor on the

      network building and discarding circuits every 30 seconds, which

      added overall load to the network, used bandwidth and battery from

      clients that weren't actively using their Tor, and kept sockets open

      on guards which added connection padding essentially forever. Fixes

      bug 40981; bugfix on 0.4.8.1-alpha;

src/core/or/circuituse.c

+7 −2
Original line number Diff line number Diff line
@@ -1202,8 +1202,13 @@ circuit_predict_and_launch_new(void) 
  int flags = 0;



  /* Attempt to launch predicted conflux circuits. This is outside the HS or

   * Exit preemptive circuit set. */

   * Exit preemptive circuit set.

   * As with the other types of preemptive circuits, we only want to

   * launch them if we have predicted ports. (If we haven't needed a

   * circuit for a while, maybe we won't need one soon either.) */

  if (predicted_ports_prediction_time_remaining(now)) {

    conflux_predict_new(now);

  }



  /* Count how many of each type of circuit we currently have. */

  SMARTLIST_FOREACH_BEGIN(circuit_get_global_list(), circuit_t *, circ) {