Re: Decoupling BEEP Sessions and TCP Connections

On Tue, 2003-02-18 at 12:09, Tunnel Team wrote:
> > On Mon, 2003-02-17 at 11:50, Chip Bradford wrote:
> > > Hi,
> > >
> > > I am a member of a team working at Harvey Mudd College to implement a
> Tunnel
> > > profile for RoadRunner. For our implementation, we are thinking it would
> be
> > > useful to be able to close a BEEP session without closing the underlying
> TCP
> > > socket and to be able to create a new BEEP session which uses a
> previously
> > > created socket. We would like to know if there is any support currently
> for
> > > these actions and, if not, what the best way to implement them would be.
> > >
> > Hi,
> >
> > A tuning reset is probably what you are looking for. You can look at the
> > "rot13" profile in the RoadRunner source tree or the RR/TLS profile for
> > an example on how to do a tuning reset.
> >
> > / Jonas
> 
> This is actually not quite what we need. The Tunnel specification requires a
> proxy to have two different BEEP sessions running (for example, one
> connection to the client and another one to the final server). Once Tunnel
> has been negotiated over these sessions, we need to be able to start passing
> bytes transparently (ie, stop trying to interpret traffic as a BEEP stream)
> so we would like to be able to close down the BEEP sessions without closing
> the underlying sockets. We can then start passing data from one socket to
> the other without worry about BEEP getting in the way.
> 
> As per a previous suggestion quite a while ago, we had been trying to access
> the underlying g_io_channels to pass data. RoadRunner, however, seems to be
> reading the data before we are able to. Even if we could get this method
> working, closing down the BEEP session would still be prefered since it
> ensures that no interpretation of the data will occur and it eliminates any
> overhead which might be required to run the RoadRunner BEEP session (this is
> important for a proxy which is most likey a firewall/router type machine and
> needs to be able to easily handle many connections.)
> 
> We haven't been able to find any functionality in the RoadRunner libraries
> which fulfills our requirements, but if there is some undocumented feature
> that could help us it would be nice to know about it. Since these features
> seem potentially usefull beyond our specific needs (the other BEEP
> implementations we are using support these things) it might be worth-while
> to add them to RoadRunner. If this cannot be done in the near future,
> however, we will need to figure out on our own how to startup and shutdown a
> BEEP session without affecting the underlying socket. In this case, any
> advice you can offer or explaination of the current code you can give would
> be greatly appreciated.
> 
Ah sorry, I misunderstood you.

I have an idea on how to solve this that you can try:

Add this function to rr-tcpconnection.c:

GIOChannel *
rr_tcp_connection_get_iochannel (RRTCPConnection *tcpc)
{
	g_return_val_if_fail (RR_IS_TCP_CONNECTION (tcpc), NULL);

	return tcpc->priv->iochannel;  /* on the CVS version */
	return tcpc->iochannel;        /* if you are using the 
                                        * 0.9.1  release */
}


To shut down the session without closing the connection
you do like this:

iochannel = rr_tcp_connection_get_iochannel (RR_TCP_CONNECTION (conn));
/* make sure the socket isn't closed */
g_io_channel_ref (iochannel);
/* close the session, the connection object will also be unrefed once
 * but the iochannel (socket) is still open */
rr_connection_disconnect (conn, error);

/* You can get the socked fd like this: */
fd = g_io_channel_unix_get_fd (iochannel);

/* close the iochannel when you are done */
g_io_channel_unref (iochannel);


The simplest way to copy data between the two iochannels
is probably to use the glib event loop. Take a look
at the "add_watch_full" function in rr-tcpconnection.c

add_watch_full is used instead of g_io_add_watch to use
the main loop thread that RoadRunner runs.

Btw, is the Tunnel profile Open Source? Can I access your current
source code. It would make it much easier to give more helpful
answers.

/ Jonas
-- 
Jonas Borgström                  [email protected]
CodeFactory AB                   http://www.codefactory.se/
Office: +46 (0)90 71 86 14