[tor-bugs] #25429 [Obfuscation/Snowflake]: Need something better than client's `checkForStaleness`

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#25429: Need something better than client's `checkForStaleness`
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 Reporter:  arlolra                |          Owner:  (none)
     Type:  defect                 |         Status:  new
 Priority:  Medium                 |      Milestone:
Component:  Obfuscation/Snowflake  |        Version:
 Severity:  Normal                 |     Resolution:
 Keywords:                         |  Actual Points:
Parent ID:                         |         Points:
 Reviewer:                         |        Sponsor:
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Comment (by dcf):

 Replying to [comment:2 arlolra]:
 > > I wonder if the repeated disconnections after 30 seconds is also the
 cause of ...
 >
 > I doubt it.  Commenting out `// go c.checkForStaleness()` doesn't have
 any effect on that log line.

 That test may not work without deleting the state file in between--I
 believe this message comes from parsing the `pb_` parameters in a `Guard`
 line in the state file:
 {{{
 Guard in=bridges rsa_id=2B280B23E1107BB62ABFC40DDCC8824814F80A72
 bridge_addr=0.0.3.0:1 sampled_on=2018-03-01T19:18:39
 sampled_by=0.3.3.2-alpha listed=1 confirmed_on=2018-02-26T22:51:38
 confirmed_idx=0 pb_use_attempts=70.011719 pb_use_successes=46.431641
 pb_circ_attempts=207.411194 pb_circ_successes=199.674622
 pb_successful_circuits_closed=76.945984 pb_collapsed_circuits=94.614807
 pb_unusable_circuits=28.113830 pb_timeouts=1.649048
 }}}
 Since the state file persists between runs, you wouldn't see the message
 go away until you had had enough successful connections to push the
 average down below some threshold, or something like that. And it seems
 that tor will only emit the message once, keeping track of whether it has
 done so in a `path_bias_use_extreme` variable, so that could explain why
 it is only seen at startup:
 https://gitweb.torproject.org/tor.git/tree/src/or/entrynodes.h?h=tor-0.3.2.10#n46
 https://gitweb.torproject.org/tor.git/tree/src/or/circpathbias.c?h=tor-0.3.2.10#n1284
 But as for what to do with `checkForStaleness`, I don't understand its
 purpose either, but if we can't figure it out, we could just bump it up to
 a high value, like 5 hours or so.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/25429#comment:3>
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