Don't consider a port "handled" by an isolated circuit.

Previously, circuit_stream_is_being_handled incorrectly reported an exit port as "handled" by a circuit (meaning that the circuit could be used by any future stream using that exit port) regardless of whether the circuit was already isolated in some way. This meant that, in Tor Browser, circuit_get_unhandled_ports was reporting that all ports were handled even though all non-internal circuits had already been isolated by SOCKS username+password. Therefore, circuit_predict_and_launch_new was declining to launch new exit circuits. Then, when the user visited a new site in Tor Browser, a stream with new SOCKS credentials would be initiated, and the stream would have to wait while a new circuit with those credentials could be built. That was bad for time-to-first-byte. Now, clean, not-yet-isolated circuit(s) will be automatically launched ahead of time and be ready for use whenever a new stream with new SOCKS credentials (or other isolation criteria) is initiated. Fixes bug 18859.
arthuredelstein · Dec 6, 2017 · e4b9f956e7c05862d6088a1b56f3e91f8326a91b · e4b9f95
1 parent 01700d7
commit e4b9f956e7c05862d6088a1b56f3e91f8326a91b
Showing with 3 additions and 1 deletion.

+3 −1 src/or/circuituse.c
diff --git a/src/or/circuituse.c b/src/or/circuituse.c
@@ -1001,7 +1001,7 @@ circuit_remove_handled_ports(smartlist_t *needed_ports)
     tor_assert(*port);
     if (circuit_stream_is_being_handled(NULL, *port,
                                         MIN_CIRCUITS_HANDLING_STREAM)) {
-//      log_debug(LD_CIRC,"Port %d is already being handled; removing.", port);
+      log_debug(LD_CIRC,"Port %d is already being handled; removing.", *port);
       smartlist_del(needed_ports, i--);
       tor_free(port);
     } else {
@@ -1038,6 +1038,8 @@ circuit_stream_is_being_handled(entry_connection_t *conn,
         continue;
       if (origin_circ->unusable_for_new_conns)
         continue;
+      if (origin_circ->isolation_values_set)
+        continue;
 
       exitnode = build_state_get_exit_node(build_state);
       if (exitnode && (!need_uptime || build_state->need_uptime)) {