This POC aims to create an IPv6 overlay network completely writing in Rust. The overlay network uses some of the core principles of the Babel routing protocol (https://www.irif.fr/~jch/software/babel/). Each node that joins the overlay network will receive an overlay network IP in the 200::/7 range.

Currently, only Linux is supported.

First, get an useable binary, either by downloading an artifact from a release, or by checking out and building the code yourself.

Once you have an useable binary, simply start it. If you want to connect to other nodes, you can specify their listening address as part of the command

mycelium --peers 203.0.113.5:9651

By default, the node will listen on port 9651, though this can be overwritten with the -p flag.

The node uses a x25519 key pair from which its identity is derived. The private key of this key pair is saved in a local file (32 bytes in binary format). You can specify the path to this file with the -k flag. By default, the file is saved in the current working directory as priv_key.bin.

It is possible to run the system without creating a TUN interface, by starting with the --no-tun flag. Obviously, this means that your node won't be able to send or receive L3 traffic. There is no interface to send packets on, and consequently no interface to send received packets out of. From the point of other nodes, your node will simply drop all incoming L3 traffic destined for it. The node will still route traffic as normal. It takes part in routing, exchanges route info, and forwards packets not intended for itself.

The node also still allows access to the message subsystem.

The node starts an HTTP API, which by default listens on localhost:8989. A different listening address can be specified on the CLI when starting the system through the --api-server-addr flag. The API allows access to send and receive messages, and will later be expanded to allow admin functionality on the system. Note that message are sent using the identity of the node, and a future admin API can be used to change the system behavior. As such, care should be taken that this API is not accessible to unauthorized users.

A message system is provided which allows users to send a message, which is essentially just "some data" to a remote. Since the system is end-to-end encrypted, a receiver of a message is sure of the authenticity and confidentiality of the content. The system does not interpret the data in any way and handles it as an opaque block of bytes. Messages are sent with a deadline. This means the system continuously tries to send (part of) the message, until it either succeeds, or the deadline expires. This happens similar to the way TCP handles data. Messages are transmitted in chunks, which are embedded in the same data stream used by L3 packets. As such, intermediate nodes can't distinguish between regular L3 and message data.

The primary way to interact with the message system is through the API. The message API is documented in an OpenAPI spec in the docs folder. For some more info about how to use the message system, see the message docs.

Using the inspect subcommand, you can view the address associated with a public key. If no public key is provided, the node will show its own public key. In either case, the derived address is also printed. You can specify the path to the private key with the -k flag. If the file does not exist, a new private key will be generated. The optional --json flag can be used to print the information in json format.

mycelium inspect a47c1d6f2a15b2c670d3a88fbe0aeb301ced12f7bcb4c8e3aa877b20f8559c02
Public key: a47c1d6f2a15b2c670d3a88fbe0aeb301ced12f7bcb4c8e3aa877b20f8559c02
Address: 27f:b2c5:a944:4dad:9cb1:da4:8bf7:7e65

mycelium inspect --json
{
  "publicKey": "955bf6bea5e1150fd8e270c12e5b2fc08f08f7c5f3799d10550096cc137d671b",
  "address": "34f:b680:ba6e:7ced:355f:346f:d97b:eecb"
}

This project is built in Rust, and you must have a rust compiler to build the code yourself. Please refer to the official rust documentation for information on how to install rustc and cargo. Aside from the rust toolchain, no other dependencies should be required to build the project.

First make sure you have cloned the repo

git clone https://github.com/threefoldtech/mycelium.git

Then go into the cloned directory and build it

cd mycelium
cargo build

In case a release build is required, the --release flag can be added to the cargo command (cargo build --release).