Re: [PATCH v5 11/21] tools: add simple vchan-socket-proxy

[Ian Jackson <ian.jackson@xxxxxxxxxx>]

Jason Andryuk writes ("[PATCH v5 11/21] tools: add simple vchan-socket-proxy"):
> From: Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>
> 
> Add a simple proxy for tunneling socket connection over vchan. This is
> based on existing vchan-node* applications, but extended with socket
> support. vchan-socket-proxy serves both as a client and as a server,
> depending on parameters. It can be used to transparently communicate
> with an application in another domian that normally expose UNIX socket
> interface. Specifically, it's written to communicate with qemu running
> within stubdom.
> 
> Server mode listens for vchan connections and when one is opened,
> connects to a pointed UNIX socket.  Client mode listens on UNIX
> socket and when someone connects, opens a vchan connection.  Only
> a single connection at a time is supported.
> 
> Additionally, socket can be provided as a number - in which case it's
> interpreted as already open FD (in case of UNIX listening socket -
> listen() needs to be already called). Or "-" meaning stdin/stdout - in
> which case it is reduced to vchan-node2 functionality.
> 
> Example usage:
> 
> 1. (in dom0) vchan-socket-proxy --mode=client <DOMID>
>     /local/domain/<DOMID>/data/vchan/1234 /run/qemu.(DOMID)
> 
> 2. (in DOMID) vchan-socket-proxy --mode=server 0
>    /local/domain/<DOMID>/data/vchan/1234 /run/qemu.(DOMID)
> 
> This will listen on /run/qemu.(DOMID) in dom0 and whenever connection is
> made, it will connect to DOMID, where server process will connect to
> /run/qemu.(DOMID) there. When client disconnects, vchan connection is
> terminated and server vchan-socket-proxy process also disconnects from
> qemu.
> 
> Signed-off-by: Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>
> Reviewed-by: Jason Andryuk <jandryuk@xxxxxxxxx>
> Signed-off-by: Jason Andryuk <jandryuk@xxxxxxxxx>

I have not reviewed this.  It sounds very useful.  Thank you!
(I did skim over it.)

Acked-by: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>