Timeout dead connections

[Matt Johnston]

Hi,

The attached attached patch against 2013.56 should fix it, or
https://secure.ucc.asn.au/hg/dropbear/rev/70811267715c

Dropbear wasn't running cleanup handlers when it exited due
to the TCP connection being closed.

Matt

On Thu, Mar 28, 2013 at 07:24:55PM +0800, Matt Johnston wrote:
> I think that -K on the server should be enough. On the
> server can you run "tcpdump -i eth0 -w cap1.cap port 22",
> get a ssh session going, pull out the cable, wait 10
> minutes, then send me the capture?
> 
> Could you also check that the Dropbear process for the
> connection is still running after the connection should have
> been finished. It's possible that the process is exiting but
> the session cleanup code isn't working correctly. The whole
> debug log might give me an idea what's going on.
> 
> Cheers,
> Matt
> 
> On Thu, Mar 28, 2013 at 09:56:02AM +0100, Mattias Walström wrote:
> > Thanks for your responses, all your suggestions imply that you should do something
> > in the client (set keepalive on client end), but shouldn't the server itself be able to
> > decide if a client is dead (can't OpenSSH do this?).
> > 
> > If I do the -K 15 -I 20 on the server end only, this will close the connection when
> > the OpenSSH client has not sent any characters in 20s. I expected the keepalive to be
> > two way, that the server got responses on these packages as well, is that not the case?
> > 
> > Regards
> >  Mattias
> 
> > >>On Wed, Mar 27, 2013 at 11:24 AM, Mattias Walström <
> > >>mattias.walstrom at westermo.se> wrote:
> > >>
> > >>>Hi!
> > >>>I am running dropbear 2013.56, connecting to the server with a PC but
> > >>>not performing a clean close (I pulled my ethernet cable), this caused
> > >>>dropbear to never drop its connection.
> > >>>
> > >>>Looking at the utmp entries, I could see that the connection never got
> > >>>dropped,
> > >>>the utmp entries was kept forever, and running with debug indicates that
> > >>>also.
> > >>>  Tried to use -K to send keepalive, but it just keeps sending keepalives
> > >>>to the peer,
> > >>>even it is no longer there, and not possible to reach. Shouldn't
> > >>>the connection be dropped if the keepalive does not reach its destination?
> > >>>
> > >>>I know there is the -I option, but that does not really do what I want,
> > >>>I want the connection to be tear down when the peer is unreachable, not
> > >>>when the user has been idle for a while.
> > >>>
> > >>>Regards
> > >>>  Mattias
> > >>>
> >