[tor-bugs] #9574 [Tor]: Process ntor create cells before tap create cells?

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#9574: Process ntor create cells before tap create cells?
-----------------------------+---------------------------------------
     Reporter:  arma         |      Owner:
         Type:  enhancement  |     Status:  new
     Priority:  normal       |  Milestone:  Tor: 0.2.5.x-final
    Component:  Tor          |    Version:
   Resolution:               |   Keywords:  tor-relay, maybe-proposal
Actual Points:               |  Parent ID:
       Points:               |
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Comment (by gmorehouse):

 I'd just like to chime in with the fact that, running 0.2.3.x a couple
 months ago on a Raspberry Pi, I'd see transient "circuit creation storms"
 characterized by several '''thousand''' "your computer is too slow to
 handle this many circuit creation attempts" messages suppressed as
 duplicate in '''one second''' in the logs.  The Pi is a low resource
 machine with a slow processor.  After later upgrading to Tor 0.2.4.x, this
 decreased very much and Tor used less CPU in general; but after this DDOS-
 like activity started, the Pi has been acting like a canary in a coal
 mine.  It actually crashed for the first time (out-of-memory killed) last
 night on 0.2.4.16-rc.  Meanwhile I've barely seen a ripple (at least big
 enough to warrant any logging, circuits are up) on my VPS relays.

 This makes me wonder two things.

 1. Was I seeing a "test run" a couple months back on the Pi running
 0.2.3.x?  Or was that "normal" activity?

 2. Wouldn't ''thousands'' of "two slow" messages per second, if occurring
 under "normal" (though suboptimal) network conditions and with a
 reasonable MaxAdvertisedBandwidth on a 700MHz ARM chip, be considered a
 bug in its own right?  I wanted to bring it up because Roger responded to
 my original questions[1] and suggested it was a known issue with the
 normal (though in this case suboptimal) operation of the Tor network.
 None of the tickets he mentioned dealt with huge amounts of "too slow to
 handle this many creation requests" messages, though; I wonder if any of
 the tickets he mentioned, though[2][3][4], are points that the DDOS may be
 exploiting?  Food for thought.

 [1] https://lists.torproject.org/pipermail/tor-
 relays/2013-June/002184.html
 [2] https://trac.torproject.org/projects/tor/ticket/3825
 [3] https://trac.torproject.org/projects/tor/ticket/4862
 [4] https://trac.torproject.org/projects/tor/ticket/8950

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/9574#comment:7>
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