Awesome

Caution: Sharp Edges

This library is intended as a test/prototype library and exploration of the possibility space around testing networking code in the MirageOS library operating systems project. It is usable as a drop-in replacement for the stock MirageOS ARP module supplied by tcpip -- for an example, see this example unikernel. For limitations, please see a more thorough explanation of the project.

To Build

The following unreleased package is required:

opam pin add irmin-network-datastores https://github.com/yomimono/irmin-network-datastores.git

The following dependencies are needed from the default opam repository:

opam install irmin irmin-unix alcotest ezjsonm lwt ipaddr ounit mirage-clock-unix mirage-unix tcpip mirage mirage-types

make should now conclude successfully; if not, please let me know!

What Does This Thing Do?

A more thorough explanation of this code's aims and actions is available on my blog.

The ARP implementation given uses Irmin to store a Map representing the ARP cache. This is functorized and can be either an in-memory Irmin store or a Git-backed store on a filesystem. (Currently, only the in-memory store is available to MirageOS unikernels running on Xen.)

Tests are included which use Magnus Skjegstad's mirage-vnetif library to mock out communications between network devices using the mirage-tcpip Ethernet protocol implementation.

Test code is included which uses the Git-backed filesystem store to make assertions about the operations performed on the cache as a result of certain packet inputs.

To see something interesting happen, build the tests:

ocaml setup.ml -configure --enable-tests
make test

Git repositories reflecting test state will be generated in the subdirectory test_results. For example, to see commits and merges made by the "speaker" interface during the entries_aged_out test:

cd test_results/entries_aged_out/speaker
git log --all --graph --oneline

Alternately, interacting with the state of the repository via the graphical git repository browser gitk is also of potential interest. Be sure to invoke gitk --all if you're interested in seeing all the branches (you probably are!).

There is also a demo which simulates multiple network nodes communicating over a TCP built on top of Irmin-ARP with the in-memory backend. Build and run it with:

ocaml setup.ml -configure --enable-demo
make
./demo_network.native