This is an implementation of the Xen "libvchan" or "vchan" communication protocol in OCaml. It allows fast inter-domain communication using shared memory.
Make sure your systems are properly configured. You may need to:
sudo modprobe xen-evtchn
sudo modprobe xen-gntdev
sudo modprobe xen-gntalloc
mount -t xenfs xenfs /proc/xen
To connect as a server to a client with domid 'domid' and using the string 'port' to denote the connection:
open Vchan_lwt_unix
open_server ~domid ~port ()
>>= fun (ic, oc) ->
Lwt_io.write_line oc "hello"
>>= fun () ->
Lwt_io.flush oc
>>= fun () ->
Lwt_io.close ic
>>= fun () ->
Lwt_io.close oc
To connect as a client, replace open_server with open_client.
On both of your VMs, find their domain ids:
xenstore-read domid
On the domain with domid <server domid>, listen for a single connection from
<client domid> on <port>:
xencat -l <client domid> <port>
On the domain with domid <client domid>, connect to <server domid>:
xencat <server domid> <port>
So to transfer a file foo from domid 1 to domid 2:
On domain 2, listen for the connection and retrieve the file:
xencat -l 1 foo > copy-of-foo
On domain 1, transmit the file:
cat foo | xencat 2 foo