[tor-bugs] #33097 [Core Tor/Tor]: outbuf_flushlen seems to serve no purpose

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#33097: outbuf_flushlen seems to serve no purpose
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     Reporter:  nickm         |      Owner:  nickm
         Type:  defect        |     Status:  assigned
     Priority:  Medium        |  Milestone:  Tor: 0.4.4.x-final
    Component:  Core Tor/Tor  |    Version:
     Severity:  Normal        |   Keywords:
Actual Points:                |  Parent ID:
       Points:                |   Reviewer:
      Sponsor:                |
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 The "outbuf_flushlen" field in connection_t seems to not actually do
 anything that's distinct from buf_datalen(conn->outbuf)... except
 possibly, to get out of sync with it under rare conditions?  (eg #32472).

 Flushlen once existed to implement rate limiting: it was introduced in
 117cbeeaaf30cdb before we even had round robining.  Later there was some
 logic involved with f5ebf4c712d693c to try to flush full TLS records.  And
 controller connections used ab838bddb89f to force early flushing there...
 but right now, we don't flush according to the same logic that we used to
 flush, and I think outbuf_flushlen is now obsolete.

 I think there's a case to be made for removing this field in 0.4.3, but
 I'd like to be cautious.

 Adding arma to cc in case he can remember what outbuf_flushlen is for.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/33097>
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