[tor-bugs] #6799 [Tor Relay]: Don't expire unused relay-to-relay TLS conns so quickly

Mon Sep 10 01:55:08 UTC 2012

#6799: Don't expire unused relay-to-relay TLS conns so quickly
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 Reporter:  arma       |          Owner:     
     Type:  defect     |         Status:  new
 Priority:  normal     |      Milestone:     
Component:  Tor Relay  |        Version:     
 Keywords:             |         Parent:     
   Points:             |   Actualpoints:     
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 In git commit 67b38d506 we changed conn timeouts so relays would close
 idle conns (that is, conns without any circs on them) after 3 minutes
 rather than 15 minutes.

 We made the change because of the "clients holding their dir-fetching
 conns open for a long time, filling up descriptor lists and memory and
 knocking over relays" fun:
 http://archives.seul.org/tor/relays/Apr-2010/msg00073.html

 But it would appear that we made worse the problem that Torscan exploits.
 We don't need to be so aggressive about closing connections to/from other
 relays (besides, they weren't the problem before).

 There's a downside here, which is that we end up using more file
 descriptors on relays. But if most links are used already, we don't use
 many more. And if most links aren't used already, the Torscan problems are
 worse.

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/6799>
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