[tor-bugs] #18642 [Core Tor/Tor]: Teach the OOM handler about the DNS cache

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#18642: Teach the OOM handler about the DNS cache
-------------------------------------------------+-------------------------
 Reporter:  nickm                                |          Owner:  (none)
     Type:  enhancement                          |         Status:
                                                 |  needs_revision
 Priority:  Medium                               |      Milestone:  Tor:
                                                 |  0.3.5.x-final
Component:  Core Tor/Tor                         |        Version:
 Severity:  Normal                               |     Resolution:
 Keywords:  tor-dos, oom, tor-relay, dns, 035    |  Actual Points:
  -triaged-in-20180711                           |
Parent ID:                                       |         Points:  1
 Reviewer:  dgoulet                              |        Sponsor:
                                                 |  SponsorV-can
-------------------------------------------------+-------------------------
Changes (by dgoulet):

 * status:  needs_review => needs_revision


Comment:

 True, `ExitRelay` won't work. I'm also not very enthusiastic on using
 `policy_is_reject_star()` which possibly goes over the entire policy just
 to learn if we are an Exit relay with a non reject policy.

 The Roles we've added recently for the callbacks in tor should be what we
 look for imo but don't have one for the Exit just yet (#25899).

 So for now, lets always run it, checking the HT size is very cheap and the
 OOM is only triggered on memory pressure so shouldn't be that often in
 most cases.

 Sorry neel, the PR looks good, just remove the `ExitRelay` condition :P.
 Thanks!

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/18642#comment:28>
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