package vchan

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Description

This is an implementation of the Xen "libvchan" or "vchan" communication protocol in OCaml. It allows fast inter-domain communication using shared memory.

Tags

org:mirage

Published: 29 Mar 2019

README

README.md

This is an implementation of the Xen "libvchan" or "vchan" communication protocol in OCaml. It allows fast inter-domain communication using shared memory.

Linux configuration

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 use in Linux

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.

To use the command-line

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

Dev Dependencies (1)

  1. ounit with-test

Used by (6)

  1. conduit-mirage < "2.0.2"
  2. jitsu
  3. mirage-conduit < "2.1.0" | >= "3.0.0"
  4. mirage-http = "2.0.0"
  5. vchan-unix >= "4.0.2" & < "5.0.0"
  6. vchan-xen = "4.0.2"

Conflicts

None

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