[tor-bugs] #23356 [Obfuscation/Snowflake]: proxy-go starts using 100% CPU when network is disconnected

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#23356: proxy-go starts using 100% CPU when network is disconnected
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     Reporter:  dcf                    |      Owner:  (none)
         Type:  defect                 |     Status:  new
     Priority:  Medium                 |  Milestone:
    Component:  Obfuscation/Snowflake  |    Version:
     Severity:  Normal                 |   Keywords:
Actual Points:                         |  Parent ID:
       Points:                         |   Reviewer:
      Sponsor:                         |
---------------------------------------+--------------------
 A power outage disconnected the network of a laptop on which I was running
 proxy-go. The laptop battery kept the computer running until the power
 came back on, but the network was still down. When I checked on it, the
 log was filled with 2.4 GB of
 {{{
 2017/08/29 10:02:33 error polling broker: Post https://snowflake-
 reg.appspot.com/proxy: dial tcp: lookup snowflake-reg.appspot.com on <dns
 server>:53: dial udp <dns server>:53: connect: network is unreachable
 2017/08/29 10:02:33 error polling broker: Post https://snowflake-
 reg.appspot.com/proxy: dial tcp: lookup snowflake-reg.appspot.com on <dns
 server>:53: dial udp <dns server>:53: connect: network is unreachable
 2017/08/29 10:02:33 error polling broker: Post https://snowflake-
 reg.appspot.com/proxy: dial tcp: lookup snowflake-reg.appspot.com on <dns
 server>:53: dial udp <dns server>:53: connect: network is unreachable
 }}}

 There were 11,879,088 of these messages over the course of about an hour
 (according to the log timestamps), so about 3,330 messages per second. I'm
 guessing the code was in a tight failure loop.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/23356>
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