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Re: connection reuse with proxies and ssl

From: Daniel Stenberg <>
Date: Mon, 28 Jan 2008 13:40:13 +0100 (CET)

On Sun, 27 Jan 2008, Gautam Kachroo wrote:

>> The question is of course what to do about this situation. Do we stop
>> allowing the method used in test 509 or do we somehow allow it and make
>> sure that the re-used connection's SSL connection is continued to the
>> complete state? Or is there any other alternatives?
> I got the test to work by turning on forking in sws. The problem when sws
> doesn't fork is that the server is blocked waiting for a request on the
> first connection. Of course, there is never a request on that connection
> since the client has initiated a second connection. When connection reuse is
> forbidden, the first connection is closed which frees up the server for the
> second request. Otherwise, before this patch, the connection is reused which
> doesn't cause the server to be hung. With this patch, the first connection
> lingers keeping the (non-forking) server blocked.
> I think that means the patch is fine.

I'm torn back and forth on this.

The fact that you need to do a second request for test 509 basically disables
what test 509 tries to do: a redirect to the correct URL while still
connected. Because if that's not possible (anymore) to do, the application
could just as well just figure out the "true" URL in a first request and then
make a second one on its own. I'm not saying this is entirelly ruled out, but
it'll practically revert Peter Sylvester's change from January 12th 2004 that
introduced this ability.

> There may be a concern about keeping a connection to the server lingering,
> but that's not the worst thing in the world since test 509 seems like a rare
> case. Of course, Curl_done could close the first connection when it sees
> that the ssl connection state is not complete. There's no point in having
> the connection in the connection cache if it willl never be re-used.

Yeah, if there's no code to continue the SSL connection negoation on a
subsequent re-use, there's no point in keeping it around. However, this makes
me very puzzled since then how come test 509 works today (without this patch)
then? Isn't this simply a proof that this patch sets the SSL connection to a
"complete" state a bit too late and that the connection in 509 should rather
be seen as negotiated and fine since obviously it can be re-used fine?

I'm not prepared to run the sws server in forked mode just yet without further
investigations that things will work fine with it. The fork option was mostly
added for when I've done stand-alone controlled tests.

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Received on 2008-01-28