Re: [gtk-vnc-devel] RFC: api for openning a tunnelled connection

["Daniel P. Berrange" <berrange redhat com>]

On Wed, Aug 29, 2007 at 08:48:47AM -0300, Jonh Wendell wrote:
> Em Ter, 2007-08-28 às 22:39 +0100, Daniel P. Berrange escreveu:
> > We currently have two APIs for openning connections
> > 
> >    vnc_display_open_fd  - takes a pre-opened file handle
> >    vnc_display_open_host - takes hostname & servicename (aka port)
> > 
> > Another pretty common way to access VNC servers is by tunnelling them over
> > SSH. Now obviously any client apps could implement this themselves by forking
> > ssh and then calling vnc_display_open_fd. I don't particularly want to have
> > to implement this multiple times in each app though. So what do people think
> > about having an explicit API for openning an SSH tunnelled connection, and
> > even an arbitrary 'external' tunnel script (cf CVS 'ext' method).
> > 
> > 
> >   vnc_display_open_ssh_tunnel(VncDisplay *d, const char *user, const char *host, const char *port)
> >   vnc_display_open_ext_tunnel(VncDisplay *d, const char *script);
> > 
> > Or just one todo both ....
> > 
> >    vnc_display_open_ext_tunnel(VncDisplay *d, const char **argv);
> > 
> > Attaching a crude impl of the SSH tunnel impl
> > 
> > Regards,
> > Dan.
> 
> Hi, Dan.
> 
> Really this is a great feature. I never connected into a machine via ssh
> tunelled connection. So, some questions:
> 
> - Doesn't it need a password?

Yes & no. Personally I'd just define it as supported if-only-if you have
setup SSH keys (and SSH agent to avoid entering passphrase). Feeding an
SSH password prompt back up to the user is  really painful.

> - The port parameter is the port of VNC or port of SSH?

Of the VNC server on the remote host.

> - What about use the same api (vnc_display_open_host), just adding a
> boolean parameter to indicate if the connection is via ssh or not?

I think we at very least ned a username for SSH, possibly also an SSH
port number. Adding extra APIs in the vnc_display module doesn't cause
any significant code duplication, because ultimately they all feed into
the same GVNC calls where most of the setup code is. So I prefer to have
explicit APIs for each open.

Dan.
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