Qt-interest Archive, August 2007
Possible problem with QTcpServer + many connections?
Message 1 in thread
Hi,
I am working with the torrent example in examples/network/torrent. And I must say,
this program drives me crazy. When I have torrents with many seeds it stops
working after a time with a 'too many files open' error. The reason are hundreds
of sockets in CLOSE_WAIT state, which remain indefinitely in this state and slowly
eating my file resources away.
The last two days I was looking for a possible bug in the program, but was unable
to find one. I just discovered something strange, which might either be a problem
with my Linux (don't think so), a possible lack of knowledge regarding tcp
connections on my side (possible), or a bug in QTcpServer or QTcpSocket
(unlikely?).
I logged all incoming and outgoing connections. These are the connections, which I
initiate from the list I get from a tracker and the connections, which are
initiated from outside peers, who got my address from a tracker. When I now
compare the sockets in CLOSE_WAIT state with this list, I find only address/port
pairs to which I never had a connections. Does anyone has an explanation for this?
Actually the CLOSE_WAIT problem happens only when I allow outside initiated
connections. When I force the torrentserver class to listen to an internal
address, which effectively switches it off, I don't have this problem.
Could it be that the QTcpServer is 'deaf' for a certain percentage of incoming
connections? A socket is opened, the program/the QTcpServer gets not information
about this socket, the peer closes his side, since he gets no data and on my side a
CLOSE_WAIT socket remains?
Of course it is possible that I missed somewhere a third location in the code,
which opens sockets (apart from the http connection to the tracker). If this is
the case, I'd appreciate a hint. :-)
Guido
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Message 2 in thread
Looks like I found the problem in the torrent code (90% sure). Does Trolltech
accept patches? :-)
Guido
On Mon, Aug 13, 2007 at 03:13:04PM +0200, Guido Seifert wrote:
> Hi,
> I am working with the torrent example in examples/network/torrent. And I must say,
> this program drives me crazy. When I have torrents with many seeds it stops
> working after a time with a 'too many files open' error. The reason are hundreds
> of sockets in CLOSE_WAIT state, which remain indefinitely in this state and slowly
> eating my file resources away.
>
--
[ signature omitted ]
Message 3 in thread
On mandag den 13. August 2007, Guido Seifert wrote:
> Looks like I found the problem in the torrent code (90% sure). Does
> Trolltech accept patches? :-)
Of course. Send a mail to bugs@xxxxxxxxxxxxx and include your patch.
Bo.
> On Mon, Aug 13, 2007 at 03:13:04PM +0200, Guido Seifert wrote:
> > Hi,
> > I am working with the torrent example in examples/network/torrent. And I
> > must say, this program drives me crazy. When I have torrents with many
> > seeds it stops working after a time with a 'too many files open' error.
> > The reason are hundreds of sockets in CLOSE_WAIT state, which remain
> > indefinitely in this state and slowly eating my file resources away.
>
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Message 4 in thread
I don't think they would just take your patch and apply it, but if you
add a patch to a bug report, it certainly will help them fixing the bug
;)
Cheers,
Peter
> -----Original Message-----
> From: Guido Seifert [mailto:wargand@xxxxxx]
> Sent: Monday, August 13, 2007 9:50 PM
> To: TrolltechInterest
> Subject: Re: Possible problem with QTcpServer + many connections?
>
>
> Looks like I found the problem in the torrent code (90%
> sure). Does Trolltech
> accept patches? :-)
>
> Guido
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Message 5 in thread
On 8/14/07, Peter Prade <prade@xxxxxxxxxxx> wrote:
> I don't think they would just take your patch and apply it, but if you
> add a patch to a bug report, it certainly will help them fixing the bug
> ;)
They did for me :). But yes, adding a patch will certainly help in
resolving the bug quicker.
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