Re: X11 Forwarding

[Dustin Oprea <myselfasunder@xxxxxxxxx>]

Where does that decision fit into the library? It only appears to be
referenced from this one function, which is not specific to X11, and it
looks like it only matters if the callback is defined, regardless of
whether request_x11 has previously been called.

static int *ssh_execute_client_request*(ssh_session session, ssh_message
msg)
{
    ssh_channel channel = NULL;
    int rc = SSH_AGAIN;

*    if (msg->type == SSH_REQUEST_CHANNEL_OPEN*
*        && msg->channel_request_open.type == SSH_CHANNEL_X11*
*        && ssh_callbacks_exists(session->common.callbacks,
channel_open_request_x11_function)) {*
        channel = *
session->common.callbacks->channel_open_request_x11_function* (session,
                msg->channel_request_open.originator,
                msg->channel_request_open.originator_port,
                session->common.callbacks->userdata);



Dustin



On Fri, Sep 13, 2013 at 1:46 AM, Aris Adamantiadis <aris@xxxxxxxxxxxx>wrote:

> Hi,
>
> request_x11 is still required because that's how you tell the server you
> wish to use X11.
> The callback you implement should return a new ssh channel from
> ssh_channel_new. This in order to keep object ownership (ssh_channel) to
> the application.
>
> Kr,
>
> Aris
> Le 13/09/13 06:02, Dustin Oprea a écrit :
> > Does that mean that the request_x11() and/or accept_x11() no longer need
> > to be called?
> >
> > What am I doing inside the callback.. Just do ssh_channel_new(), or do I
> > do an accept_x11() and return the ssh_channel from that?
> >
> > I always appreciate your help, Aris.
> >
> >
> > On Thu, Sep 12, 2013 at 1:36 PM, Aris Adamantiadis <aris@xxxxxxxxxxxx
> > <mailto:aris@xxxxxxxxxxxx>> wrote:
> >
> >     Hi Dustin,
> >
> >     ssh_channel_accept_x11() is called shortly after request_x11 when you
> >     know that you're going to receive an X11 socket. However since 0.6rc
> >     there's a session-defined callback to handle new X11 connections:
> >
> >     /**
> >      * @brief Handles an SSH new channel open X11 request. This happens
> when
> >     the server
> >      * sends back an X11 connection attempt. This is a client-side API
> >      * @param session current session handler
> >      * @param userdata Userdata to be passed to the callback function.
> >      * @returns a valid ssh_channel handle if the request is to be
> allowed
> >      * @returns NULL if the request should not be allowed
> >      * @warning The channel pointer returned by this callback must be
> closed
> >     by the application.
> >      */
> >     typedef ssh_channel (*ssh_channel_open_request_x11_callback)
> >     (ssh_session session,
> >           const char * originator_address, int originator_port, void
> >     *userdata);
> >
> >     struct ssh_callbacks_struct {
> >     /* ... */
> >       /** This function will be called when an incoming X11 request is
> >     received.
> >        */
> >       ssh_channel_open_request_x11_callback
> >     channel_open_request_x11_function;
> >     };
> >
> >     I tested this in an application for a client but unfortunately don't
> >     have any example around. However it's pretty simple if you look at
> the
> >     other callback-based examples (like proxy.c or samplesshd-cb.c)
> >
> >     Kr,
> >
> >     Aris
> >
> >     Le 12/09/13 12:58, Dustin Oprea a écrit :
> >     > Does someone have experience with X11 forwarding? I'm current
> fixing
> >     > another anomaly, but I wanted to get my thoughts straight on this.
> >     This
> >     > is the theoretical process as it makes sense to me:
> >     >
> >     > 1) ssh_channel_accept_x11(). Is this done between reads on the
> client,
> >     > on a separate thread,.. or where?
> >     > 2) At this point, we should have a X11 channel, returned from the
> >     accept
> >     > call.
> >     > 3) ssh_channel_request_pty()
> >     > 4) ssh_channel_change_pty_size()
> >     > 5) ssh_channel_request_x11()
> >     > 6) ssh_channel_request_shell()
> >     >
> >     > What now? Loop over communication on the shell channel -as well
> >     as- the
> >     > X11 channel?
> >     >
> >     > Are there any unnecessary steps, above (like the pty_size() call)?
> >     >
> >     >
> >     > Thanks. This is just about the only principal function that isn't
> >     > clearly covered by the tutorials.
> >     >
> >     > Dustin
> >     >
> >
> >
> >
>
>
>