libertaria-stack/core/l2_session

L2 Session Manager

Sovereign peer-to-peer session management for Libertaria.

Overview

The L2 Session Manager establishes and maintains cryptographically verified sessions between Libertaria nodes. It provides:

• Post-quantum security (X25519Kyber768 hybrid)
• Resilient state machines (graceful degradation, automatic recovery)
• Seamless key rotation (no message loss during rotation)
• Multi-transport support (QUIC primary, μTCP fallback)

Why No WebSockets

This module explicitly excludes WebSockets (see ADR-001). We use:

Transport	Use Case	Advantages
QUIC	Primary transport	0-RTT, built-in TLS, multiplexing
μTCP	Fallback, legacy	Micro-optimized, minimal overhead
UDP	Discovery, broadcast	Stateless, fast probing

WebSockets add HTTP overhead, proxy complexity, and fragility. Libertaria is built for the 2030s, not the 2010s.

Quick Start

// Establish session
let session = try l2_session.establish(
    peer_did: "did:morpheus:abc123",
    config: .{ ttl: 24h, heartbeat: 30s },
    ctx: ctx
);

// Use session
try session.send(message);
let response = try session.receive(timeout: 5s);

State Machine

idle → handshake_initiated → established → degraded → suspended
         ↓                           ↓          ↓
       failed                    rotating → established

See SPEC.md for full details.

Module Structure

File	Purpose
session.zig	Core Session struct and API
state.zig	State machine definitions and transitions
handshake.zig	PQxdh handshake implementation
heartbeat.zig	Keepalive and TTL management
rotation.zig	Key rotation without interruption
transport.zig	QUIC/μTCP abstraction layer
error.zig	Session-specific error types
config.zig	Configuration structures

Testing

Tests are colocated in test_*.zig files. Run with:

zig build test-l2-session

Specification

Full specification in SPEC.md.