rust_ofp

OpenFlow 1.0 protocol and controller in Rust.

rust_ofp aims to implement the OpenFlow1.0 protocol, for purposes of prototyping SDN systems in Rust. In the future, this may grow to support other OpenFlow specifications (namely 1.3), and others protocols entirely.

I'm drawing heavily on inspiration and code structure from the frenetic-lang project, due to my familiarity with it. I hope that Rust will enable a more natural implementation of the low-level protocol than OCaml + CStructs, and true parallelism will allow for higher controller performance and a simpler event loop.

See my blog post on the crate here!

Building

rust_ofp is composed of a Rust library implementing the OpenFlow 1.0 protocol, and a rust_ofp_controller binary that currently acts as little more than an echo server for SDN configurations. It can be built and run by the normal means for Rust projects.

cd path/to/rust_ofp
cargo build
cargo run

Testing

I'm performing all correctness evaluation in mininet for the time being. Mininet offers quick feedback, as much scalability as I need for now, and should properly support OpenFlow 1.0 (and other protocols). There is no reason correctness in mininet shouldn't transfer to physical hardware as well, and maybe one day I'll get around to testing out that hypothesis.

Anyway, testing the controller binary is pretty straightforward, assuming mininet is installed. In one terminal

cd path/to/rust_ofp
cargo run

In another terminal

sudo  mn --controller=remote

The terminal running rust_ofp_controller will occasionally print some things out, logging a rough idea of the types of messages it receives, and behaviors it performs.

The mininet terminal should launch an interactive shell with the typical mininet utilities.

Currently, the test executable for rust_ofp implements MAC learning, so as hosts ping eachother, the controller installs forwarding rules on switches rather than routing all packets through the controller.

Documentation

Travis CI automatically uploads source documentation generated by cargo doc.

• rust_ofp
• rust_ofp_controller

ToDo

Some parts of the OpenFlow 1.0 standard remain unimplemented. Notably, rust_ofp does not currently implement the following message codes:

• OFPT_VENDOR
• OFPT_GET_CONFIG_REQUEST/OFPT_GET_CONFIG_REPLY
• OFPT_SET_CONFIG
• OFPT_PORT_MOD
• OFPT_STATS_REQUEST/OFPT_STATS_REPLY
• OFPT_QUEUE_GET_CONFIG_REQUEST/OFPT_QUEUE_GET_CONFIG_REPLY

The current controller executable is a minimal wrapper around the protocol that doesn't dynamically handle any rule configuration. Future goals for the controller include:

• A GTK GUI for configuring and querying an SDN dynamically.
• A compiler from some higher-level abstraction to install a forwarding policy other than a global DROP on launch.
• Consistent Updates for dynamically updating an SDN's global forwarding policy.