Files
fips/docs/design
Johnathan Corgan 45a8a4cd9b Merge branch 'master' into next
Forward-merge of 12 master commits past the previous merge
(823b830, master @ 18019bb): dep-audit bumps (rand,
clap, tun, rtnetlink, windows-service, plus the bump-safe
lockfile batch), bloom-storm chaos scenario, control-socket
resolver consolidation, gateway dns.listen default change,
OpenWrt ipk README refresh, gateway tutorial review, Ethernet
MTU rustdoc fix, dead session-variant drop, CHANGELOG prep.

Conflict resolution:

- CHANGELOG.md: both bullets kept under [Unreleased] / Fixed.
  Master's spanning-tree internal-path-propagation fix precedes
  next's tree-ancestry-test determinism entry and the
  responder-Disconnect XX-handshake entry.
- src/protocol/session.rs: kept next's SessionSetup/SessionAck
  variants and rustdoc. Master's drop of those variants suits
  v0.3.0's FSP phase-byte dispatch but is undone by next's
  v0.4.0 wire format, which retains the variants and uses the
  inner msg_type byte for handshake identification.
- src/transport/ethernet/mod.rs: kept next's "interface MTU - 4"
  comment. Master corrected the v0.3.0 3-byte rustdoc; next
  redesigned the framing to a 4-byte header (type/flags/length)
  for shared-media beacons, so master's correction does not
  apply to next's format.

Auto-merged cleanly: Cargo.toml (next's 0.4.0-dev + the new dep
pins from master), Cargo.lock, all gateway docs,
docs/reference/configuration.md, packaging files,
.github/workflows/ci.yml, testing/chaos/sim/* and
testing/ci-local.sh (bloom-storm additions), src/config/*.

Local verification: cargo build --release, cargo test (1252
passed, 4 ignored), cargo clippy -D warnings, cargo fmt --check
all green.
2026-05-08 18:47:13 +00:00
..
2026-05-08 13:45:04 +00:00

FIPS Design

Architectural and protocol-level explanations for FIPS — the why and the how behind the wire and the system. For wire formats and configuration keys, see reference/. For task recipes, see how-to/. For end-to-end lessons, see tutorials/.

Reading Order

Start with fips-concepts.md for the novice-friendly framing of what FIPS is and why, then move to fips-architecture.md for the protocol stack, identity model, and two-layer encryption walkthrough. From there, follow the protocol stack from bottom to top. After the stack, fips-mesh-operation.md explains how the pieces work together at runtime. Cross-cutting and supporting documents cover specific subsystems in detail.

Foundations

Document Description
fips-concepts.md What FIPS is, why it exists, mental model
fips-architecture.md Protocol stack, identity, two-layer encryption
fips-prior-work.md Designs and protocols FIPS builds on

Protocol Stack

Document Description
fips-transport-layer.md Transport layer: datagram delivery over arbitrary media
fips-mesh-layer.md FIPS Mesh Protocol (FMP): peer authentication, link encryption, forwarding
fips-session-layer.md FIPS Session Protocol (FSP): end-to-end encryption, sessions
fips-ipv6-adapter.md IPv6 adaptation: TUN interface, DNS, MTU enforcement

Cross-Cutting

Document Description
fips-mmp.md Metrics Measurement Protocol (link + session)
fips-mtu.md Path MTU model, encapsulation overhead, PMTUD
fips-security.md fips0 interface threat model and default-deny baseline

Mesh Behavior

Document Description
fips-mesh-operation.md How the mesh operates: routing, discovery, error recovery
fips-nostr-discovery.md Optional Nostr-mediated peer discovery and UDP NAT hole-punch
port-advertisement-and-nat-traversal.md Nostr-signaled port advertisement and UDP NAT-traversal protocol; generic, with FIPS as an example implementation

Deeper Dives

Document Description
fips-spanning-tree.md Spanning tree algorithms: root discovery, parent selection, coordinates
fips-bloom-filters.md Bloom filter properties: FPR analysis, size classes, split-horizon
spanning-tree-dynamics.md Spanning tree walkthroughs: convergence scenarios, worked examples

Adjacent Components

Document Description
fips-gateway.md fips-gateway service: outbound (LAN-to-mesh) DNS-proxy + virtual-IP NAT and inbound (mesh-to-LAN) port-forwarding, sharing one nftables table