Bugs item #1376945, was opened at 2005-12-09 08:12
Message generated for change (Comment added) made by evgenys
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Category: https
Group: bad behaviour
Status: Open
Resolution: None
Priority: 5
Submitted By: Evgeny Sabelsky (evgenys)
Assigned to: Daniel Stenberg (bagder)
Summary: CLOSE_WAIT problem

Initial Comment:
curl 7.15.1 (i686-pc-linux-gnu) libcurl/7.15.1
OpenSSL/0.9.8a zlib/1.1.3
Protocols: tftp ftp gopher telnet dict ldap http file
https ftps
Features: IPv6 Largefile NTLM SSL libz

In multithread application several threads is doing
https requests to localhost, every request is
(curl_easy_init->curl_easy_perform-
>curl_easy_cleanup), sometime libCurl (or openssl??)
do not close sockets and after a bunch of requests i
see handreds of CLOSE_WAIT strings in nestat.
CLOSE_WAIT disappears if i close my application.

i checked, curl_easy_cleanup called EVERY TIME.

Evgeny

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>Comment By: Evgeny Sabelsky (evgenys)
Date: 2005-12-09 09:05

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FYI, CURLOPT_FORBID_REUSE fixed the problem.
think need to investigate it or document this solution for
application with persistent curl handle.

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Comment By: Daniel Stenberg (bagder)
Date: 2005-12-09 08:31

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Explicit close when perform() is done is forced with
CURLOPT_FORBID_REUSE.

And yes, libcurl _does_ close the connections in cleanup().

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Comment By: Evgeny Sabelsky (evgenys)
Date: 2005-12-09 08:27

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Ok, i'll try to reproduce it in a small app.
How can i force close ? I have checked _cleanup method,
seems like it should cleans connections by

  while(-1 != ConnectionKillOne(data))
    ; /* empty loop */

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Comment By: Daniel Stenberg (bagder)
Date: 2005-12-09 08:21

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How many threads? How many sockets are in CLOSE_WAIT?

libcurl keep sockets "open" by default after a
curl_easy_perform(), to be prepared to re-use the connection
on a subsequent call to it again. But if the call doesn't
come within a limited time, the remote server might decide
to close down the connection anyway and the socket ends up
in CLOSE_WAIT.

You can avoid this by forcing libcurl to close the sockets
after use, which then of course disables persistent
connections on subsequent calls.

Can you reproduce this problem with a small stand-alone app
that you can provide the source for?

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Received on 2005-12-09