[tor-bugs] #20071 [Core Tor/Tor]: Tor clients need 4 routers when connecting via IPv6, but only 3 using IPv4

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#20071: Tor clients need 4 routers when connecting via IPv6, but only 3 using IPv4
---------------------------+---------------------
 Reporter:  teor           |          Owner:
     Type:  defect         |         Status:  new
 Priority:  Low            |      Milestone:
Component:  Core Tor/Tor   |        Version:
 Severity:  Minor          |     Resolution:
 Keywords:  testing, ipv6  |  Actual Points:
Parent ID:  #19989         |         Points:  2
 Reviewer:                 |        Sponsor:
---------------------------+---------------------

Comment (by arma):

 That log message comes from
 {{{
   if (num_acceptable_routers < routelen) {
     log_info(LD_CIRC,
              "Not enough acceptable routers (%d/%d). Discarding this
 circuit.",
              num_acceptable_routers, routelen);
     return -1;
   }
 }}}
 so it would seem that routelen is 4 for this case (rather than "one of the
 routers is unacceptable").

 routelen gets set here:
 {{{
   routelen = DEFAULT_ROUTE_LEN;
   if (exit_ei &&
       purpose != CIRCUIT_PURPOSE_TESTING &&
       purpose != CIRCUIT_PURPOSE_S_ESTABLISH_INTRO)
     routelen++;
 }}}

 So: are you causing this ipv6 circuit to be called in such a way that
 you're specifying which exit it should use, and it's not a testing or
 server-side-establish-intro circuit?

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/20071#comment:1>
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