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Johnathan Corgan
0d93a19e07
Cost-based parent selection: - Replace depth-only parent selection with effective_depth = depth + link_cost - link_cost computed from locally measured MMP metrics: etx * (1.0 + srtt_ms / 100.0) - Prevents bottleneck subtrees in heterogeneous networks where a LoRa link at depth 1 would otherwise always beat fiber at depth 2 - Configurable hysteresis (default 0.2) prevents marginal parent switches - Configurable hold-down timer (default 30s) suppresses re-evaluation after parent switch - Mandatory switches (parent lost, root change) bypass both safeguards - Link costs passed as HashMap parameter to keep TreeState pure Periodic re-evaluation: - evaluate_parent() was only called on TreeAnnounce receipt or parent loss; after tree stabilization, link degradation went undetected - Added timer-based re-evaluation (reeval_interval_secs, default 60s) that calls evaluate_parent() from the tick handler with current MMP link costs - Respects existing hold-down and hysteresis safeguards - Short-circuits when disabled or <2 peers Design documentation: - Update 7 design docs to reflect cost-based parent selection - Replace depth-only algorithm descriptions with effective_depth model - Replace rejected cumulative path cost spec with local-only design rationale - Rewrite Example 2 (heterogeneous links) for local-only cost model - Update config docs: parent_switch_threshold replaced by parent_hysteresis, hold_down_secs, reeval_interval_secs Chaos simulation enhancements: - fips_overrides with deep merge for per-scenario FIPS config customization - Explicit topology algorithm for deterministic test graphs - Control socket querying via fipsctl for tree/MMP snapshot collection - Edge existence validation in netem manager - Per-link netem policy overrides - 9 new chaos scenarios covering cost avoidance, depth-vs-cost tradeoffs, stability, mixed topologies, periodic re-evaluation, and bottleneck parent 12 new unit tests, 667 total passing, clippy clean.
FIPS Testing
Integration and simulation test harnesses for FIPS, using Docker containers running the full protocol stack.
Test Harnesses
static/ -- Static Docker Network
Fixed topologies (mesh, chain) with 5 nodes. Manual scripts for building, config generation, connectivity tests (ping, iperf), and network impairment (netem). Useful for deterministic debugging and validating specific topology configurations.
chaos/ -- Stochastic Simulation
Automated randomized testing with configurable node counts, topology algorithms (random geometric, Erdos-Renyi, chain), and fault injection (netem mutation, link flaps, traffic generation, node churn). Scenarios are defined in YAML and executed via a Python harness that manages the full lifecycle: topology generation, Docker orchestration, fault scheduling, log collection, and analysis.