Files
fips/docs/design
Johnathan Corgan 434b9726aa node: establish dataplane/ and session/ concept homes (behavior-neutral)
Reorganize the node module tree by concept rather than by
message-handling verb, as the first step of the node runtime
decomposition. Pure relocation: no wire, config, metric, or log
semantics change; the lib test count is unchanged (1577 passed).

Moves (git mv, 100% rename similarity):
- handlers/{forwarding,rx_loop,connected_udp,dispatch,encrypted}.rs
  -> node/dataplane/ — the whole RX hot path (the select! run loop,
  transit/local forwarding, the link-message router, the RX decrypt
  path with responder K-bit cutover + roam writes, and connected-UDP
  fast-path activation) now lives in one home.
- node/session.rs -> node/session/mod.rs — establishes the session
  concept home for the data/state types. The message-behavior file
  handlers/session.rs stays put for now (folds in with the later FSP
  session step).

The IK/XX-divergent establishment files (handlers/{handshake,rekey,
timeout}.rs) and the deferred-home files (handlers/{mmp,lookup}.rs)
deliberately stay in handlers/, to move once rather than twice.

Every module is reached through impl Node methods, so no call site or
re-export shim was needed. Updated in lockstep with the moves: the
module_path!-derived tracing targets in the two mesh-lab compose-trace
overlays, a structural test's include_str! source path, doc-comments
in proto/routing and the mesh-lab docs, and the stale source-location
citations (node/handlers/{forwarding,rx_loop,encrypted}.rs and
node/session.rs) in doc-comments and the discovery design doc.
2026-07-12 19:22:08 +00:00
..
2026-06-07 23:30:35 +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