[tor-bugs] #4483 [Tor]: If k of n authorities are down, k/n bootstrapping clients are delayed for minutes

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#4483: If k of n authorities are down, k/n bootstrapping clients are delayed for
minutes
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 Reporter:  arma                                 |          Owner:  teor
     Type:  defect                               |         Status:
 Priority:  High                                 |  needs_review
Component:  Tor                                  |      Milestone:  Tor:
 Severity:  Normal                               |  0.2.8.x-final
 Keywords:  performance, bootstrap, dirauth-     |        Version:
  dos-resistance, tor-client, large-feature,     |     Resolution:
  prop210, 028-triage, TorCoreTeam201512,        |  Actual Points:
  MikePerry201512R                               |         Points:
Parent ID:  #2664                                |  medium/large
  Sponsor:  SponsorU                             |
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Comment (by nickm):

 Starting to review v10, since that's what I see...

 (Please do not do a rebase that changes stuff in these commits; instead,
 make fixup! or squash! commits so that I can review the changes and won't
 have to re-review what I've already been over.)

 452272b4b7c03b1504fb8d04054473b275fa18e2 (#17574) --
   * I am not sure about the must/should distinction at all.  We'd like to
 avoid loops, sure, but I kinda feel like it isn't really true that a
 fallbackdir ''must never'' ask another fallback dir for information.  Must
 think more here.

 f4397294e75dc4a419e8dfca95f1cf4e745e842a (#17716) --
   * maybe a router_digest_is_fallback_dir function would be handy to have.

 607fdd0a52f4ee41fe0cc27a102db53681a6aff4 (Refactor connection_get_* to
 produce lists and counts)
   * There is a huge amount of duplicate code here.  Having the same
 12-line function written   more than once is just asking for trouble
 IMNSHO.
   * strcmp_opt() could simply two of these functions.
   * In connection.h, you're calling free(conns), not
 smartlist_free(conns).

 88821fe930d5275eadec3125e097674124477b30 (Add want_authority to
 directory_get_from_dirserver)
   * Are the only options really DL_WANT_AUTHORITY and DL_WANT_FALLBACK ?
 Shouldn't there be a third state for "any cache would be okay" ?  Or am I
 not understanding right?  (In that case, please consider making the
 documentation more idiot-friendly)

 bc8f21f7bd4ed3ea52da94f44c58f34919841307 (Add attempt-based connection
 schedules)
   * .... (more to follow)...

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/4483#comment:39>
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