Files
fips/README.md
Tom 34e00b9f6e Add Nostr-mediated overlay discovery and UDP NAT traversal (#53)
Optional peer discovery and NAT hole-punching path gated behind a new
`nostr-discovery` cargo feature. Nodes publish signed overlay endpoint
adverts to public Nostr relays, consume peer adverts to populate
fallback dial addresses, and use STUN-assisted UDP hole punching with
NIP-59 gift-wrap offer/answer signaling to establish direct UDP paths
between NATed peers. Once a punched socket is up, it is handed into
the existing FIPS UDP transport and the standard Noise/FMP session
stack takes over unchanged.

The cargo feature is in the default feature set
(`default = ["nostr-discovery"]`) so stock builds include it; a
build that explicitly disables default features (or selects a
feature set without `nostr-discovery`) does not link the nostr /
nostr-sdk crates and does not emit a no-op poll in the tick loop.
Runtime behavior is independently gated by
`node.discovery.nostr.enabled`, which defaults to false; if the
config enables Nostr on a non-feature build, startup logs a
warning and continues without it.

== Cargo feature and dependencies

- New cargo feature `nostr-discovery = ["dep:nostr", "dep:nostr-sdk"]`.
  Not in the default feature set.
- New optional Linux-only dependencies: `nostr 0.44` (features: std,
  nip59) and `nostr-sdk 0.44`. Gift-wrap unwrap is hand-rolled in
  `src/discovery/nostr/signal.rs` rather than relying on the SDK's
  rumor-author check, which FIPS sidesteps by trusting `seal.pubkey`
  exclusively.

== Wire format

Overlay advert event: `kind 37195`, parameterized replaceable
(NIP-01 application-defined replaceable range 30000-39999), with
`d = "fips-overlay-v1"`. The digits visually spell FIPS (7=F, 1=I,
9=P, 5=S); a relay survey confirmed the kind is unused.

Advert content carries the version tag, endpoint list
(`udp|tcp|tor` + addr), optional signal-relay and stun-server
metadata, and `issuedAt` / `expiresAt` timestamps. Endpoint
`addr: "nat"` is the sentinel that triggers traversal on the peer
side. NIP-40 `expiration` tag bounds staleness on permanent
shutdown. Lifecycle relies on parameterized-replaceable
supersession; the daemon does not emit NIP-09 kind-5 deletes —
strict relays (Damus, Primal) race delete-against-replace and can
silently drop the replacement.

Gift-wrapped signal event: `kind 21059`. Punch packets carry magic
values `PUNCH_MAGIC` / `PUNCH_ACK_MAGIC`, a sequence number, and a
16-byte session hash.

== Discovery surface

- `src/discovery.rs` (always compiled)
  - `EstablishedTraversal`: bound UDP socket + selected remote +
    peer npub + optional transport name/config tuning overrides.
  - `BootstrapHandoffResult`: returned on successful handoff —
    allocated transport id, local/remote addrs, peer NodeAddr,
    session id.
- `src/discovery/nostr/` (`#![cfg(feature = "nostr-discovery")]`)
  - `types.rs`: wire and control types described above. `ADVERT_KIND`
    constant. `BootstrapError` enumerates failure modes (disabled,
    missing advert, missing NAT endpoint, no usable relays, invalid
    advert, invalid npub, signal timeout, punch timeout, replay,
    STUN failure, protocol, nostr, io, serde, event-parse).
  - `runtime.rs`: `NostrDiscovery` coordinator. Owns the shared
    nostr-sdk `Client`, subscribes to advert + signal event kinds,
    maintains a bounded advert cache and a bounded seen-sessions
    replay set, drains `BootstrapEvent::{Established, Failed}` for
    the node to consume, exposes `update_local_advert`,
    `request_connect`, `advert_endpoints_for_peer`,
    `cached_open_discovery_candidates`, and `shutdown`.
  - `signal.rs`: NIP-59 gift-wrap encode/decode. Outbound wraps are
    built against per-attempt ephemeral keys; inbound events are
    unwrapped against the node identity.
  - `stun.rs`: RFC 5389/8489 Binding Request client with
    XOR-MAPPED-ADDRESS parsing for both IPv4 and IPv6; used only to
    observe the initiator's own reflexive address against its
    locally configured STUN list (peer-advertised STUN is
    informational, never an egress target).
  - `traversal.rs`: per-attempt candidate-pair punch planner.
    Allocates a fresh `0.0.0.0:0` UDP socket per attempt, enumerates
    LAN-private and ULA interface addresses alongside the STUN
    reflexive address, schedules probe/ack exchanges at the
    configured interval for the configured duration, and picks the
    first candidate pair that authenticates end-to-end.

Strategy ordering is Reflexive↔Reflexive first, then LAN, then
Mixed. The STUN-observed pair is the only candidate that's reliable
across arbitrary network topologies; trying it first prevents the
planner from latching onto a misleading host-candidate path before
the reflexive path gets a chance. There is no catch-all
Local↔Local strategy: a previous design that paired every local
host candidate from one side with every local host candidate from
the other could declare success on a one-way reachable asymmetric
L3 path (corporate VPN, Tailscale subnet route, overlapping private
address space), only for the FMP handshake to stall because the
return path didn't match. The legitimate `Lan` strategy still pairs
candidates that share a subnet.

== Configuration surface

`node.discovery.nostr.*` (`NostrDiscoveryConfig`), all `serde(default)`
with `deny_unknown_fields`:

- `enabled` (default false), `advertise` (default true)
- `advert_relays`, `dm_relays`, `stun_servers`: defaults are
  `wss://relay.damus.io`, `wss://nos.lol`, `wss://offchain.pub`
  for both relay lists, and Google / Cloudflare / Twilio for STUN.
  Operators are expected to override for production. Other
  verified-working public relays for reference:
  `nostr.bitcoiner.social`, `nostr-pub.wellorder.net`,
  `nostr.oxtr.dev`, `nostr.mom`.
- `app` (default `"fips-overlay-v1"`), `signal_ttl_secs` (120)
- `policy`: `NostrDiscoveryPolicy::{Disabled, ConfiguredOnly (default),
  Open}` — controls whether advert-derived endpoints are consumed
  only for peers carrying `via_nostr = true`, or also for
  non-configured peers within a budget cap.
- `share_local_candidates` (default false) — when false, the offer's
  `local_addresses` list is empty and peers see only the reflexive
  address. Enable per-node only for genuinely same-LAN deployments;
  off-by-default eliminates the misleading-path failure mode for
  the common case where peers are not on the same broadcast domain.
- `open_discovery_max_pending` (64) — caps queued open-discovery
  retries; bounded by available outbound slots.
- `max_concurrent_incoming_offers` (16) — semaphore against offer
  spam; excess offers are debug-logged and dropped.
- `advert_cache_max_entries` (2048) and `seen_sessions_max_entries`
  (2048) — bound memory under ambient relay volume; overflow
  evictions are debug-logged.
- `attempt_timeout_secs` (10), `replay_window_secs` (300)
- `punch_start_delay_ms` (2000), `punch_interval_ms` (200),
  `punch_duration_ms` (10000)
- `advert_ttl_secs` (3600), `advert_refresh_secs` (1800)

Per-peer and per-transport flags:

- `PeerConfig.via_nostr: bool` — when true (and Nostr is enabled),
  advert-derived addresses are appended as fallback dial candidates
  after static addresses for that peer.
- `PeerConfig.addresses` is now `serde(default)` and may be empty
  when `via_nostr: true`; validation requires at least one of the
  two to be present per peer, and the error message names the
  peer's npub.
- `UdpConfig.advertise_on_nostr: Option<bool>` and
  `UdpConfig.public: Option<bool>` — UDP transports can be
  advertised either as direct `host:port` (public = true) or as the
  `addr: "nat"` sentinel that triggers rendezvous on the peer side.
- `TcpConfig.advertise_on_nostr` and `TorConfig.advertise_on_nostr`
  — TCP and Tor onion endpoints can be advertised as directly
  reachable.
- A reserved peer address `transport: udp, addr: "nat"` parses without
  special-casing in YAML and routes through the bootstrap runtime.

Cross-field validation (`Config::validate`, called from `Node::new`
and `Node::with_identity`):

- Any transport with `advertise_on_nostr = true` requires
  `node.discovery.nostr.enabled = true`.
- Any peer with `via_nostr = true` requires
  `node.discovery.nostr.enabled = true`.
- A non-public UDP advert (`advertise_on_nostr = true`,
  `public = false` — i.e. `udp:nat`) additionally requires at least
  one `dm_relay` and at least one `stun_server`.
  Surfaced as `ConfigError::Validation`.

== Node integration

`src/node/lifecycle.rs` is the main integration point.

- At node start (after transports are up, before TUN), if Nostr is
  enabled and the feature is compiled in, `NostrDiscovery::start` is
  invoked, the initial local overlay advert is built from the live
  transport set and published, and the runtime handle is stored.
- The rx tick loop calls `poll_nostr_discovery` (feature-gated both
  at method definition and call site), which refreshes the local
  advert, drains bootstrap events, adopts established traversals,
  schedules retries for failed traversals, and — under `policy:
  open` — enqueues outbound retries for non-configured peers
  visible in the advert cache, bounded by
  `open_discovery_max_pending` and the remaining outbound slots.
- Outbound peer dialing is refactored to `try_peer_addresses`, which
  first exhausts the static address list in priority order and only
  then appends advert-derived fallback addresses; both lists run
  through the same `attempt_peer_address_list` code path. The
  `udp:nat` sentinel address triggers `NostrDiscovery::request_connect`
  for the peer instead of a direct dial and returns `Ok(())`.
- `build_overlay_advert` walks operational transports, consults
  per-instance `UdpConfig` / `TcpConfig` / `TorConfig` (matching by
  optional transport instance name), and emits an `OverlayAdvert`
  including `signalRelays` and `stunServers` when any UDP endpoint
  is advertised as NAT.
- `adopt_established_traversal` is the bootstrap handoff API:
  allocates a new `TransportId`, constructs a `UdpTransport` with
  the user-supplied (or default) `UdpConfig`, calls the new
  `adopt_socket_async` to reuse the punched socket verbatim,
  registers the transport in the normal transport map, records it
  in `bootstrap_transports`, and calls `initiate_connection` so the
  normal handshake path runs. On failure, the transport is stopped
  and removed cleanly and the set membership is rolled back.
- On clean shutdown, `NostrDiscovery::shutdown` is awaited so
  background tasks stop before transports are torn down. (The
  advert is not explicitly retracted; NIP-40 expiration plus the
  next refresh from any live publisher supersedes it.)

New `Node` fields:

- `nostr_discovery: Option<Arc<NostrDiscovery>>` (feature-gated).
- `bootstrap_transports: HashSet<TransportId>` — per-peer UDP
  transports adopted from NAT traversal, cleaned up via
  `cleanup_bootstrap_transport_if_unused` whenever the link,
  connection, peer, or pending-connect referencing them is removed.

Retry and error surface:

- `RetryState.expires_at_ms: Option<u64>` — optional absolute expiry
  for a retry entry. `pump_retries` drops expired entries with an
  info log. Used for open-discovery retries, which expire at two
  times the advert TTL.
- New `NodeError::BootstrapHandoff(String)` returned from
  `adopt_established_traversal` when the underlying transport
  adoption fails or local address discovery fails.
- New `ConfigError::Validation(String)`.
- A small refactor extracts `Node::now_ms()` and reuses it across
  lifecycle, rx-loop tick, and timeout bookkeeping.

== UDP transport

`src/transport/udp/`:

- `UdpRawSocket::adopt(std::net::UdpSocket, recv_buf, send_buf)`:
  adopts an externally bound socket, makes it non-blocking, applies
  the configured buffer sizes (warning if the kernel clamps), and
  reports the resulting local address. Preserves the NAT mapping —
  no rebind.
- `UdpTransport::adopt_socket_async(std::net::UdpSocket)`: the
  `start_async` analogue for an already-bound socket, wiring the
  async socket and recv task exactly as the fresh-bind path would.
- `Drop` impl for `UdpTransport`: if a transport is dropped while
  still holding a recv task or socket (for example on error
  teardown), aborts the task, clears the socket, and emits a debug
  log so the cleanup is visible in tracing rather than silent.

== Logging and observability

Default `EnvFilter` demotes third-party relay-pool DEBUG output to
TRACE-only: `nostr_relay_pool`, `nostr_sdk`, and `nostr` are pinned
at INFO when our level is anything below TRACE, and at TRACE when
our level is TRACE — so the raw frames are still reachable when
explicitly asked for. RUST_LOG continues to override completely.

Concise one-line DEBUG events are emitted at the meaningful points
in the discovery / hole-punch sequence:

- `advert: published` (event id, relay count, endpoints, ttl)
- `advert: peer cached` (notify-loop ingress for non-self)
- `advert: resolved` (cache hit / relay fetch outcome)
- `traversal: initiator starting`
- `traversal: initiator STUN observed` (reflexive, local count)
- `traversal: offer sent` (session id, relay count, event id)
- `traversal: answer received` (accepted, reflexive, local)
- `traversal: initiator punch succeeded` (remote addr)
- `traversal: offer received` (responder side)
- `traversal: responder STUN observed`
- `traversal: answer sent`
- `traversal: responder punch succeeded`

Npubs are shortened to `npub1<4>..<4>` and event/session ids to
their first 8 hex characters.

Other operator-facing logs:

- `UdpTransport` adoption and drop paths log at info / debug.
- `adopt_established_traversal` logs at debug on entry and info on
  successful return, tagged with peer npub, session id, transport
  id, and both socket endpoints, so the bootstrap handoff is
  traceable end-to-end alongside the `UdpTransport::drop` log.
- `cleanup_bootstrap_transport_if_unused` logs at debug when the
  reference-count check drops an adopted transport.
- `connect_peer` tags its entry `debug!` with `peer_npub` so
  downstream STUN, punch, and handshake logs for the same peer
  correlate for operators.
- Advert-cache and seen-sessions overflow evictions log at debug so
  mis-sized caps are visible under ambient relay volume.
- Gift-wrap unwrap failures on `SIGNAL_KIND` events log at trace
  (hot path: fires for every unrelated signal event on the same
  relay).
- Traversal-offer handler failures log at debug. Expected conditions
  such as punch timeout on symmetric NAT are covered there; real
  problems are reported upstream via `BootstrapEvent::Failed`.
- Inbound-offer rate-limit messages name the governing config field
  (`max_concurrent_incoming_offers`) and state that the offer was
  rate-limited rather than failing.

== Tests

- 18 new unit tests in `src/discovery/nostr/tests.rs` covering advert
  encoding, signal envelope round-trip, STUN parsing, punch-packet
  codec, and replay-window enforcement. Run under the
  `nostr-discovery` feature.
- Config-validation tests in `src/config/mod.rs` covering the three
  cross-field invariants and YAML parsing of the full
  `node.discovery.nostr` block plus `peers[].via_nostr`, empty
  `addresses` with `via_nostr: true`, and a `udp: nat` address.
- `src/node/tests/bootstrap.rs` integration tests that drive a
  synthetic traversal (bound UDP socket pair + synthetic peer
  identity) through `adopt_established_traversal` and assert the
  Noise handshake completes over the adopted socket.
- Punch-planner tests assert reflexive-before-LAN ordering and that
  same-LAN scenarios still include the LAN target in the plan.
- `testing/nat/` Docker NAT lab harness:
  - Local `strfry` relay, local STUN responder, and one or two
    router containers performing `iptables` NAT.
  - Node LAN interfaces are provisioned with explicit `veth` pairs
    injected into the node and router namespaces so every packet
    traverses the router namespace (plain Docker bridges are not
    used for the LAN).
  - `cone` scenario: both peers behind full-cone-emulation NAT
    (SNAT with source-port preservation, inbound DNAT back to the
    single LAN host regardless of remote source); asserts UDP
    traversal succeeds and link remote addresses are on the router
    WAN subnet.
  - `symmetric` scenario: `MASQUERADE --random-fully`; asserts UDP
    traversal fails and TCP fallback converges over router-
    published WAN addresses.
  - `lan` scenario: both peers share a LAN subnet; asserts LAN
    addresses are preferred over reflexive ones.
  - Cleanup tears down all profile-gated services
    (`--profile cone --profile symmetric --profile lan`) so no
    orphan containers survive a run.
- `testing/scripts/build.sh` builds the Docker test image with
  `--features "tui nostr-discovery"` by default so NAT-harness
  binaries include bootstrap support.

== CI

- Linux release build and nextest unit-test job both use
  `--features "gateway nostr-discovery"` so the feature-gated code
  and its unit tests compile and run in CI.
- Three new integration matrix entries (`nat-cone`, `nat-symmetric`,
  `nat-lan`) invoke `testing/nat/scripts/nat-test.sh`, collect
  `docker compose logs` on failure, and always stop containers.

== Packaging and operations

- `packaging/common/fips.yaml` ships a fully commented
  `node.discovery.nostr.*` block, plus documented
  `advertise_on_nostr` / `public` examples under the UDP transport,
  an `advertise_on_nostr` example under TCP, and a `via_nostr: true`
  example under the static peer section with both a direct
  `host:port` UDP address and a `udp: nat` fallback.
- `.github/workflows/package-openwrt.yml`: NIP-94 release event
  publishes target the new default relay set.

== Documentation

- `README.md`: overlay discovery + NAT traversal moved from
  "Near-term priorities" into "What works today".
- `docs/design/fips-intro.md`: rewrites the paragraphs that
  previously described Nostr discovery and NAT traversal as future
  work; describes the shipped mechanism and the feature gate.
- `docs/design/fips-transport-layer.md`: drops the "(future
  direction)" qualifier from the Nostr Relay Discovery section,
  expands with the `udp:nat` advertisement and bootstrap handoff
  description, and updates the Current State callout.
- `docs/design/fips-mesh-layer.md`: notes that mid-session NAT
  rebinding (roaming) and initial NAT traversal (Nostr path) are
  distinct mechanisms.
- `docs/design/fips-configuration.md`: documents the full
  `node.discovery.nostr.*` surface, including the three resource
  caps and `share_local_candidates`.
- `docs/design/fips-nostr-discovery.md`: design and configuration
  reference for the shipped mechanism, including the empty-
  `addresses`-with-`via_nostr` shorthand.
- `docs/proposals/nostr-udp-hole-punch-protocol.md`: adds an
  Implemented status callout, clarifies that the punch socket is
  per-peer and per-attempt rather than shared with the application
  listener, aligns field names with the shipped JSON
  (`sessionId`, `issuedAt` / `expiresAt`, `reflexiveAddress`,
  `localAddresses`, `stunServer`), sets the `d`-tag to
  `fips-overlay-v1`, names the kind as 37195, and notes that
  advertised STUN entries are informational.
- `docs/proposals/README.md`: adds a Status column and marks the
  hole-punching proposal Implemented.
- `CHANGELOG.md`: Unreleased > Added entry covering the discovery
  path, STUN/punch path, configuration surface, and Docker NAT lab.

Co-authored-by: Johnathan Corgan <johnathan@corganlabs.com>
2026-04-27 08:15:58 -07:00

14 KiB

FIPS: Free Internetworking Peering System

banner License: MIT Rust Status

A distributed, decentralized network routing protocol for mesh nodes connecting over arbitrary transports.

FIPS is under active development. The protocol and APIs are not yet stable. See Status & Roadmap below.

Overview

FIPS is a self-organizing mesh network that operates natively over a variety of physical and logical media — local area networks, Bluetooth, serial links, radio, or the existing internet as an overlay. Nodes generate their own identities, discover each other, and route traffic without any central authority or global topology knowledge.

FIPS uses Nostr keypairs (secp256k1/schnorr) as native node identities, allowing users to generate their own persistent or ephemeral node addresses. Nodes address each other by npub, and the same cryptographic identity serves as both the routing address and the basis for end-to-end encrypted sessions across the mesh.

FIPS allows existing TCP/IP based network software to use the FIPS mesh network by generating a local IP address from the node npub and tunnelling IP packets to other endpoints transparently knowing only their npub. Native FIPS-aware applications do not need this IP tunneling or emulation capability.

All traffic over the FIPS mesh is encrypted and authenticated both hop-to-hop between peers and independently end-to-end between FIPS endpoints.

Features

  • Self-organizing mesh routing — spanning tree coordinates with bloom filter guided discovery, no global routing tables
  • Multi-transport — UDP, TCP, Ethernet, Tor, and Bluetooth (BLE L2CAP) today; designed for serial and radio
  • Noise encryption — hop-by-hop link encryption (IK) plus independent end-to-end session encryption (XK), with periodic rekey for forward secrecy
  • Nostr-native identity — secp256k1 keypairs as node addresses, no registration or central authority
  • IPv6 adaptation — TUN interface maps npubs to fd00::/8 addresses for unmodified IP applications; built-in .fips DNS resolver with optional static hostname mapping (/etc/fips/hosts)
  • Outbound LAN gateway — optional fips-gateway daemon lets unmodified LAN hosts reach .fips destinations via a DNS-allocated virtual IP pool and kernel nftables NAT
  • Metrics Measurement Protocol — per-link RTT, loss, jitter, and goodput measurement with mesh size estimation
  • ECN congestion signaling — hop-by-hop CE flag relay with RFC 3168 IPv6 marking, transport kernel drop detection
  • Operator visibilityfipsctl CLI and fipstop TUI dashboard for runtime inspection and runtime peer management
  • Zero configuration — sensible defaults; a node can start with no config file, though peer addresses are needed to join a network

Building

git clone https://github.com/jmcorgan/fips.git
cd fips
cargo build --release

Requires Rust 1.85+ (edition 2024). Linux, macOS, and Windows are supported (see transport matrix below).

Transport support by platform

Transport Linux macOS Windows OpenWrt
UDP
TCP
Ethernet
Tor
BLE

On Linux, the BLE transport requires BlueZ and libdbus. On Debian/Ubuntu: sudo apt install bluez libdbus-1-dev. Then build with BLE enabled: cargo build --release --features ble.

On OpenWrt, BLE is disabled because libdbus is not available on the target. All other transports work and ship in the default ipk.

Installation

After building, choose one of the following methods to install.

Debian / Ubuntu (.deb)

Requires cargo-deb:

cargo install cargo-deb
cargo deb
sudo dpkg -i target/debian/fips_*.deb

This installs the daemon, CLI tools, systemd units, and a default configuration. Edit /etc/fips/fips.yaml before starting:

sudo nano /etc/fips/fips.yaml
sudo systemctl start fips

The service is enabled at boot automatically. To use fipsctl and fipstop without sudo, add your user to the fips group:

sudo usermod -aG fips $USER    # log out and back in to take effect

Remove with sudo dpkg -r fips (preserves config) or sudo dpkg -P fips (removes everything including identity keys).

Generic Linux (systemd tarball)

./packaging/systemd/build-tarball.sh
tar xzf deploy/fips-*-linux-*.tar.gz
cd fips-*-linux-*/
sudo ./install.sh

See packaging/systemd/README.install.md for the full installation and configuration guide.

macOS (.pkg)

./packaging/macos/build-pkg.sh
sudo installer -pkg deploy/fips-*-macos-*.pkg -target /

This installs binaries to /usr/local/bin/, config to /usr/local/etc/fips/, sets up .fips DNS resolution via /etc/resolver/fips, and registers a launchd daemon. Edit /usr/local/etc/fips/fips.yaml before starting:

sudo nano /usr/local/etc/fips/fips.yaml
sudo launchctl load -w /Library/LaunchDaemons/com.fips.daemon.plist

Remove with sudo packaging/macos/uninstall.sh (preserves config).

To restart the node after making configuration changes:

sudo launchctl unload -w /Library/LaunchDaemons/com.fips.daemon.plist
sudo launchctl load -w /Library/LaunchDaemons/com.fips.daemon.plist

Check logs for troubleshooting:

sudo tail -f /usr/local/var/log/fips/fips.log

Note: On macOS, the TUN device is named utun<N> (kernel-assigned) rather than fips0.

Windows

Build without BLE (requires Linux-only libdbus):

cargo build --release --no-default-features --features tui

The wintun driver is required for TUN support. Download wintun.dll and place it in the same directory as fips.exe. Running the daemon requires Administrator privileges for TUN creation.

Foreground mode:

.\fips.exe -c fips.yaml

Windows Service:

# Install (requires Administrator)
.\fips.exe --install-service

# Manage via standard service tools
sc start fips
sc stop fips

# Uninstall
.\fips.exe --uninstall-service

Place fips.yaml in the current directory or %APPDATA%\fips\, or set the FIPS_CONFIG environment variable.

The control socket uses TCP on localhost:21210 instead of a Unix domain socket. fipsctl and fipstop connect to this port automatically.

Configuration

The default configuration file is installed at /etc/fips/fips.yaml:

# FIPS Node Configuration

node:
  identity:
    # By default, a new ephemeral keypair is generated on each start.
    # Uncomment persistent to keep the same identity across restarts;
    # on first start a keypair is saved to fips.key/fips.pub next to
    # this config file (mode 0600/0644).
    # persistent: true
    #
    # Or set an explicit key (overrides persistent):
    # nsec: "nsec1..."

tun:
  enabled: true
  name: fips0
  mtu: 1280

dns:
  enabled: true
  bind_addr: "127.0.0.1"
  port: 5354

transports:
  udp:
    bind_addr: "0.0.0.0:2121"

  tcp:
    # Accepts inbound connections. No static outbound peers.
    bind_addr: "0.0.0.0:8443"

  # Ethernet transport — uncomment and set your interface name.
  # ethernet:
  #   interface: "eth0"
  #   discovery: true
  #   announce: true
  #   auto_connect: true
  #   accept_connections: true

peers:
  # Static peers for bootstrapping (UDP or TCP):
  - npub: "npub1qmc3cvfz0yu2hx96nq3gp55zdan2qclealn7xshgr448d3nh6lks7zel98"
    alias: "fips-test-node"
    addresses:
      - transport: udp
        addr: "217.77.8.91:2121"
    connect_policy: auto_connect

See docs/design/fips-configuration.md for the full reference.

Usage

DNS Resolution

FIPS includes a DNS resolver (enabled by default, port 5354) that maps .fips names to fd00::/8 IPv6 addresses.

Linux: The .deb package auto-detects and configures whichever resolver is present (systemd dns-delegate, systemd-resolved, dnsmasq, or NetworkManager with dnsmasq); no manual setup is needed. For manual or tarball installs, point your resolver at 127.0.0.1:5354 for the fips domain — e.g., with systemd-resolved:

sudo resolvectl dns fips0 127.0.0.1:5354
sudo resolvectl domain fips0 ~fips

macOS: DNS is configured automatically by the .pkg installer via /etc/resolver/fips. No manual setup is needed.

Then reach any FIPS node by npub with standard IPv6 tools:

ping6 npub1bbb....fips
ssh -6 npub1bbb....fips

macOS note: Use ping6 instead of ping. macOS ships separate ping (IPv4-only) and ping6 (IPv6) binaries; ping will not resolve AAAA records. Similarly, use curl -6, ssh -6, etc. when connecting by .fips hostname.

Monitoring

Use fipsctl to query a running node:

fipsctl show status         # Node status overview
fipsctl show peers          # Authenticated peers and security state
fipsctl show links          # Active links
fipsctl show tree           # Spanning tree state
fipsctl show sessions       # End-to-end sessions and rekey health
fipsctl show bloom          # Bloom filter state
fipsctl show mmp            # MMP metrics summary
fipsctl show cache          # Coordinate cache entries and routes
fipsctl show connections    # Pending handshake connections
fipsctl show transports     # Transport instances
fipsctl show routing        # Routing, discovery, and retry state
fipsctl show identity-cache # Known node identities (npubs)

fipstop provides an interactive TUI dashboard with live-updating views of node status, peers, links, sessions, tree state, transports, and routing:

fipstop                   # connect to local daemon
fipstop -r 1              # 1-second refresh interval

Service Management

sudo systemctl start fips
sudo systemctl stop fips
sudo systemctl restart fips
sudo journalctl -u fips -f

Testing

See testing/ for Docker-based integration test harnesses including static topology tests and stochastic chaos simulation.

Examples

  • examples/sidecar-nostr-relay/ — Run a strfry Nostr relay reachable exclusively over the FIPS mesh. The relay container shares the FIPS sidecar's network namespace and is isolated from the host network.
  • examples/k8s-sidecar/ — Run FIPS as a Kubernetes Pod sidecar. The sidecar creates fips0 in the Pod's shared network namespace so every other container in the Pod gets mesh access without modification.
  • examples/wireguard-sidecar-macos/ — Reach the FIPS mesh from a macOS host through a local Docker container over a WireGuard tunnel. Only traffic destined for fd00::/8 transits the sidecar; regular internet traffic continues to use the host network.

Documentation

Protocol design documentation is in docs/design/, organized as a layered protocol specification. Start with fips-intro.md for the full protocol overview.

If you want to contribute, start with:

Project Structure

src/          Rust source (library + fips/fipsctl/fipstop/fips-gateway binaries)
packaging/    Debian, macOS .pkg, Windows ZIP, OpenWrt ipk, AUR, systemd tarball
examples/     Deployment examples (Nostr relay, K8s sidecar, macOS WireGuard)
docs/design/  Protocol design specifications
testing/      Docker-based integration test harnesses

Status & Roadmap

FIPS is at v0.2.0. The core protocol works end-to-end over UDP, TCP, Ethernet, Tor, and Bluetooth (BLE) with a small live mesh of deployed nodes.

What works today

  • Spanning tree construction with greedy coordinate routing
  • Bloom filter guided discovery (no flooding, single-path with retry)
  • Noise IK (link layer) and Noise XK (session layer) encryption
  • Periodic Noise rekey with hitless cutover for forward secrecy (FMP + FSP)
  • Persistent node identity with key file management
  • IPv6 TUN adapter with built-in .fips DNS resolver and multi-backend auto-configuration (systemd dns-delegate, systemd-resolved, dnsmasq, NetworkManager)
  • Static hostname mapping (/etc/fips/hosts) with auto-reload
  • Per-link metrics (RTT, loss, jitter, goodput) and mesh size estimation
  • ECN congestion signaling (hop-by-hop CE relay, IPv6 CE marking, kernel drop detection)
  • UDP, TCP, Ethernet, Tor, and BLE transports (BLE via L2CAP CoC with per-link MTU negotiation)
  • Outbound LAN gateway for unmodified hosts via DNS-allocated virtual IPs and nftables NAT
  • Runtime inspection and peer management via fipsctl and fipstop
  • Reproducible builds with toolchain pinning and SOURCE_DATE_EPOCH
  • Linux (Debian, systemd tarball, OpenWrt, AUR), macOS (.pkg), and Windows (ZIP, service) packaging
  • Docker-based integration and chaos testing
  • Nostr-mediated overlay endpoint discovery and UDP hole punching for NAT traversal — peers publish endpoint adverts on public Nostr relays, exchange candidates via NIP-59 gift-wrapped offers/answers, and establish direct paths through NATs using STUN-assisted punching (behind the nostr-discovery cargo feature)

Near-term priorities

  • Native API for FIPS-aware applications (npub:port addressing)
  • Security audit of cryptographic protocols

Longer-term

  • Mobile platform support
  • Bandwidth-aware routing and QoS
  • Protocol stability and versioned wire format
  • Published crate

License

MIT — see LICENSE.