A DHCP client using lwt as effectful layer






Charrua DHCP - a DHCP client, server and wire frame encoder and decoder

charrua is an
ISC-licensed DHCP library implementation in OCaml.
It provides five packages:

  • charrua: a library that handles wire traffic parsing

  • charrua-server: a DHCP server implementation

  • charrua-client: a library for handling DHCP client state and messages

  • charrua-client-lwt: a DHCP client library with timeouts and network read/write

  • charrua-client-mirage: a MirageOS-compatible set of interfaces to charrua-client-lwt

  • charrua-unix: a Unix DHCP server implementation


The name charrua is a reference to the, now extinct, semi-nomadic people of
southern South America.

Charrua consists of the single module Dhcp_wire responsible for parsing and
constructing DHCP messages,

You can browse the API for charrua at

  • Dhcp_wire provides marshalling and unmarshalling utilities for DHCP, it is the
    base for Dhcp_server.

  • Logic/sequencing is agnostic of IO and platform, so it can run on Unix as a
    process, as a Mirage unikernel or anything else.

  • All DHCP options are supported at the time of this writing.

  • Code is purely applicative.

  • It's in OCaml, so it's pretty cool.


The module Dhcp_server supports a stripped down ISC dhcpd.conf, so you can
probably just use your old dhcpd.conf. It also supports manual configuration
building in OCaml.

is a MirageOS DHCP unikernel server based on charrua,
included as a part of the MirageOS unikernel example and starting-point


charrua-client is a DHCP client powered by charrua.

The base library exposes a simple state machine in Dhcp_client
for use in acquiring a DHCP lease.

charrua-client-lwt extends charrua-client with a functor Dhcp_client_lwt,
using the provided modules for timing and networking logic,
for convenient use by a program which might wish to implement a full client.

charrua-client-mirage exposes an additional Dhcp_client_mirage for direct use
with the MirageOS library operating system.

Charrua-unix Server

charrua-unix is an ISC-licensed Unix DHCP daemon based on

  • Supports a stripped down ISC dhcpd.conf. A configuration sample can be found

  • Privilege dropping: the daemon doesn't run as root.

  • Almost purely-functional code.

  • Support for multiple interfaces/subnets.

Try charruad --help for options.

This project became one of the Mirage Pioneer