tor

commit de0fda7a79947d8243e2be45ab51bc9179eac94a
parent 28413e75605cc2d05a2a3e4c766bfbe0a47d848d
Author: David Goulet <dgoulet@torproject.org>
Date:   Wed, 19 Oct 2022 14:50:00 -0400

circ: Set proper timeout cutoff for HS circuits

Explicitly set the S_CONNECT_REND purpose to a 4-hop cutoff.

As for the established rendezvous circuit waiting on the RENDEZVOUS2,
set one that is very long considering the possible waiting time for the
service to get the request and join our rendezvous.

Part of #40694

Signed-off-by: David Goulet <dgoulet@torproject.org>

Diffstat:
M
src/core/or/circuituse.c
 | 
21
++++++++++++++++++---

1 file changed, 18 insertions(+), 3 deletions(-)
diff --git a/src/core/or/circuituse.c b/src/core/or/circuituse.c
@@ -451,7 +451,8 @@ circuit_expire_building(void)
    * custom timeouts yet */
   struct timeval general_cutoff, begindir_cutoff, fourhop_cutoff,
     close_cutoff, extremely_old_cutoff, hs_extremely_old_cutoff,
-    cannibalized_cutoff, c_intro_cutoff, s_intro_cutoff, stream_cutoff;
+    cannibalized_cutoff, c_intro_cutoff, s_intro_cutoff, stream_cutoff,
+    c_rend_ready_cutoff;
   const or_options_t *options = get_options();
   struct timeval now;
   cpath_build_state_t *build_state;
@@ -531,6 +532,16 @@ circuit_expire_building(void)
   /* Server intro circs have an extra round trip */
   SET_CUTOFF(s_intro_cutoff, get_circuit_build_timeout_ms() * (9/6.0) + 1000);
 
+  /* For circuit purpose set to: CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED.
+   *
+   * The cutoff of such circuit is very high because we end up in this state if
+   * once the INTRODUCE_ACK is received which could be before the service
+   * receives the INTRODUCE2 cell. The worst case is a full 3-hop latency
+   * (intro -> service), 4-hop circuit creation latency (service -> RP), and
+   * finally a 7-hop latency for the RENDEZVOUS2 cell to arrive (service ->
+   * client). */
+  SET_CUTOFF(c_rend_ready_cutoff, get_circuit_build_timeout_ms() * 3 + 1000);
+
   SET_CUTOFF(close_cutoff, get_circuit_build_close_time_ms());
   SET_CUTOFF(extremely_old_cutoff, get_circuit_build_close_time_ms()*2 + 1000);
 
@@ -568,8 +579,12 @@ circuit_expire_building(void)
       cutoff = c_intro_cutoff;
     else if (victim->purpose == CIRCUIT_PURPOSE_S_ESTABLISH_INTRO)
       cutoff = s_intro_cutoff;
-    else if (victim->purpose == CIRCUIT_PURPOSE_C_ESTABLISH_REND)
-      cutoff = stream_cutoff;
+    else if (victim->purpose == CIRCUIT_PURPOSE_S_CONNECT_REND) {
+      /* Service connecting to a rendezvous point is a four hop circuit. We set
+       * it explicitly here because this function is a clusterf***. */
+      cutoff = fourhop_cutoff;
+    } else if (victim->purpose == CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED)
+      cutoff = c_rend_ready_cutoff;
     else if (victim->purpose == CIRCUIT_PURPOSE_PATH_BIAS_TESTING)
       cutoff = close_cutoff;
     else if (TO_ORIGIN_CIRCUIT(victim)->has_opened &&