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


charrua is an ISC-licensed DHCP library implementation in OCaml. It provides the following 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-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.

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


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 charrua.


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