# Stellar: A stateful network functions development platform

A stateful network function could be a firewall, a load balancer, or an IDS. 

## Architecture

The stellar components are:

- **Packet IO** built an abstraction of network IO devices.
- **Session Manager** has a hash table for tracking sessions. The caller feeds packets to the session manager and may return triggered session events.
- **Plugin Manager** loads C/Lua plugins and manages per-plugin, per-session context. When the caller feeds an event to the plugin manager, it invokes plugin callbacks.
- **Protocol Decoders** are libraries that parse and extract information from the packet payload.
- **Active Queue Management** is queue management algorithm libraries that schedule packets by buffering, forwarding, marking, or dropping. A plugin creates a queue instance and enqueues packets as its needs. 
  - Question: Who consumes the dequeue events?

![stellar-high-level-design](./docs/imgs/stellar-high-level-design.png)