ae93c90908 feat(transport/ble): put the L2CAP PSM in the seam, and implement it for BlueZ
The transport dialled every peer on one configured PSM and bound its own
listener to the same one. That works only because BlueZ lets an application
choose the PSM it binds, and BlueZ is the exception: Android's
listenUsingInsecureL2capChannel and macOS's
CBPeripheralManager.publishL2CAPChannel both return an OS-assigned PSM the
application cannot request. A dialer cannot guess it, and before a connection
exists there is no channel to be told it on other than the advertisement.

So the PSM becomes a property of the seam rather than a per-backend
assumption. BleIo::listen reports the PSM it actually bound,
start_advertising takes the PSM to advertise, and BleScanner yields a
ScanAdvert -- address, plus PSM and RSSI when the backend can supply them --
instead of a bare address. The scan/probe loop keeps the learned PSM per
address alongside the probe-cooldown map it already maintains and passes it
into the existing connect(addr, psm), falling back to the configured PSM when
a peer advertises none.

The wire layout is a protocol decision and is documented in psm.rs with the
byte budget that forces it. A legacy advertising PDU carries 31 bytes; flags
take 3 and the 128-bit FIPS service UUID takes 18, which leaves too little for
service data keyed on that same 128-bit UUID. The PSM is therefore keyed on
the 16-bit UUID 0x9C90, the FIPS UUID's leading 16 bits through the Bluetooth
base UUID, costing 6 bytes for a total of 27. The budget is a const assertion,
so a change back to a 128-bit key fails the build rather than the radio. It
rides the primary advertisement, never the scan response, because a scan
response needs an active-scan round trip that drops asymmetrically across
chipsets.

The BlueZ backend now advertises and reads that service data, which is what
lets a BlueZ node tell an Android peer where to dial and learn the peer's
OS-assigned PSM in return. Emitting it costs the local_name, which no longer
fits the budget. Nothing reads a peer's advertised name -- discovery keys on
the service UUID alone, here and on maint -- so dropping it does not affect
which nodes can find each other.

Compatibility with deployed nodes is unchanged in both directions. BlueZ
listeners still bind the configured PSM, so an existing node dialling that PSM
still connects. A peer that advertises no service data yields psm: None and is
dialled at the configured PSM exactly as before. BleConfig::psm keeps its type,
default and meaning; only its doc comment changes to say it is now what to bind
and what to dial when a peer advertises nothing.

BlueZ shortens a base-range 128-bit UUID to its 16-bit form before building the
AD structure, so the service data goes out as the 6-byte AD type 0x16 the
layout requires rather than the 20-byte 0x21 form, and the advert stays inside
the PDU. Read in BlueZ 5.72: bt_string_to_uuid tests is_base_uuid128 first
(lib/uuid.c), and serialize_service_data emits BT_AD_SERVICE_DATA16 for a
2-byte UUID (src/shared/ad.c). This was the open question the change was held
on.

The BlueZ implementation moves out of io.rs into io_linux.rs at the same time.
io.rs now holds only what is platform-neutral -- the traits, ScanAdvert and the
mock -- so a new backend is a new io_<platform>.rs beside it rather than
another arm inside the shared file. The move is content-preserving: the only
changes to the relocated code are three import paths and two rustfmt reflows
caused by the dedent.

Co-authored-by: Arjen <18398758+Origami74@users.noreply.github.com>
2026-08-26 07:58:50 +01:00
2026-02-22 20:52:55 +00:00
2026-08-22 10:46:42 +01:00

FIPS: Free Internetworking Peering System

banner License: MIT Rust Status

A self-organizing encrypted mesh network built on Nostr identities, capable of operating over arbitrary transports without central infrastructure.

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

What FIPS does

A machine running FIPS becomes a node in the mesh with a self-generated cryptographic identity (a Nostr keypair). There are two equally-supported deployment modes.

As an overlay on top of existing IP networks, FIPS lets your node reach any other FIPS node wherever it sits — behind a NAT, on a different ISP, on a phone over cellular, on a laptop with only Bluetooth in range, or behind a Tor onion. The mesh forwards IPv6 traffic transparently and end-to-end encrypted, with no central VPN concentrator or coordinating server.

Ground up over raw Ethernet, WiFi, or Bluetooth, FIPS provides a complete permissionless network without any pre-existing IP infrastructure, ISP, or DNS. Any node that joins the link gets routable IPv6 addresses, peer discovery, and a path to every other node automatically.

Either way, existing networking software runs over it unchanged — SSH, HTTP servers, file transfer, anything IPv6-native works the same way it would on a local network.

Features

  • Self-organizing mesh routing. Spanning-tree coordinates with bloom-filter-guided discovery; no global routing tables, no flooding.
  • Multi-transport. UDP, TCP, Ethernet, Tor, Nym, and Bluetooth (BLE L2CAP) ship today; transports compose on a single mesh and a node may run several at once.
  • Two-layer encryption. Noise IK between peers (hop-by-hop) and Noise XK between mesh endpoints (independent end-to-end), with periodic rekey for forward secrecy.
  • Nostr-native identity. secp256k1 / schnorr keypairs as node addresses; self-generated, no registration, no central authority.
  • IPv6 adapter. A TUN interface maps each remote npub to an fd00::/8 address, so unmodified IPv6 software reaches mesh peers as <npub>.fips. Built-in .fips DNS resolver, with optional static name mapping via /etc/fips/hosts.
  • Nostr-mediated discovery and NAT traversal. Peers publish endpoint adverts on public Nostr relays, exchange candidates via NIP-59 gift-wrapped offers and answers, and establish direct paths through NATs using STUN-assisted hole punching. On the local network, mDNS LAN discovery finds peers directly without relays.
  • LAN gateway. Optional fips-gateway service folds an entire unmodified LAN into the mesh: outbound (LAN clients reach mesh destinations through a DNS-allocated virtual IPv6 pool and nftables NAT) and inbound (LAN-side services exposed to the mesh through 1:1 port forwards).
  • Per-link metrics. RTT, loss, jitter, and goodput on every hop, plus mesh-size estimation, via the Metrics Measurement Protocol.
  • ECN congestion signaling. Hop-by-hop CE-flag relay with RFC 3168 IPv6 marking and transport kernel-drop detection.
  • Mesh-interface security baseline. Optional default-deny nftables policy for fips0 shipped as a packaged conffile (/etc/fips/fips.nft) with an operator drop-in directory (/etc/fips/fips.d/) and a disabled-by-default fips-firewall.service. The baseline polices only the mesh interface, leaving Docker, Tor, and the host firewall untouched.
  • Operator visibility. fipsctl CLI for control and inspection with time-series stats history queryable for any metric, fipstop TUI for live status with inline sparkline dashboards, and a JSON-line control socket on each binary for direct programmatic access.
  • Reproducible builds with toolchain pinning and SOURCE_DATE_EPOCH.

Quick start

The shortest path on Debian / Ubuntu:

git clone https://github.com/jmcorgan/fips.git
cd fips
cargo install cargo-deb
cargo deb
sudo dpkg -i target/debian/fips_*.deb
sudo systemctl start fips

This installs the daemon, CLI tools (fipsctl, fipstop), the optional fips-gateway service, systemd units, and a default /etc/fips/fips.yaml you can edit before starting.

For macOS, Windows, OpenWrt, the systemd tarball, a Nix flake, or a from-source build, see docs/getting-started.md for the full multi-platform installation guide.

To join a live mesh and reach your first peer, follow the new-user tutorial progression starting at docs/tutorials/join-the-test-mesh.md.

Building from source

cargo build --release

Requires Rust 1.94.1+ (edition 2024). Linux, macOS, FreeBSD, and Windows run as standalone daemons; Android is supported as an embedded library (the host app owns the TUN, e.g. a VpnService). Transport availability varies by platform.

Transport Linux macOS FreeBSD Windows Android OpenWrt
UDP ✅ ✅ ✅ ✅ ✅ ✅
TCP ✅ ✅ ✅ ✅ ✅ ✅
Ethernet ✅ ✅ ❌ ❌ ❌ ✅
Tor ✅ ✅ ✅ ✅ ❌ ✅
Nym ✅ ✅ ✅ ✅ ❌ ❌
BLE ✅ ❌ ❌ ❌ ❌ ❌

On Linux, a source build requires libclang — the LAN gateway's nftables bindings are generated by bindgen at build time, which needs libclang.so on the build host. Install it before building (sudo apt install libclang-dev on Debian / Ubuntu); without it the build fails inside the rustables crate with an "Unable to find libclang" error. This is a build-time prerequisite only — it is not a runtime dependency, and the pre-built .deb artifacts do not need it.

BLE is optional and, on Linux, requires BlueZ and libdbus (sudo apt install bluez libdbus-1-dev on Debian / Ubuntu). It is gated on a build-script probe — install the dependencies first and the cargo build line above picks it up. The OpenWrt ipk omits BLE because libdbus is not available on the target.

Nym (mixnet) transport builds on all desktop platforms. The OpenWrt ❌ is provisional, pending verification of nym-socks5-client availability on the target; it will flip to ✅ only if confirmed buildable there.

Alternatively, the repo ships a Nix flake: nix develop drops you into a shell with the pinned toolchain and every build prerequisite (libclang, dbus, pkg-config) already provided, and nix build .#fips builds all four binaries with no host setup. See the Nix / NixOS section of packaging/README.md.

Documentation

docs/ is organised by reader purpose:

  • Tutorials — hand-held walk-throughs from a fresh install through to a participating mesh node, plus advanced deployments (gateway on OpenWrt, hosting services, ground-up two-device mesh).
  • How-to guides — operator recipes for specific tasks: firewall activation, Nostr discovery, Tor onion service, Bluetooth peering, LAN gateway deployment and troubleshooting, MTU diagnostics, host aliases, persistent identity, unprivileged-user setup, UDP buffer tuning.
  • Reference — fips.yaml configuration, wire formats, control-socket protocol, CLI references for each binary, security posture matrix, Nostr events catalog, transport statistics inventory.
  • Design — protocol-level architecture and layer specifications. Start with fips-concepts.md for the framing, then fips-architecture.md for the protocol stack.

If you want to contribute, see CONTRIBUTING.md and testing/README.md.

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/sidecar-nostr-mixnet-relay/ — Single-container demo of FIPS peering through a mixnet (implemented with Nym): the FIPS daemon, the mixnet proxy, and a strfry Nostr relay all in one isolated container, with the direct route to the peer firewalled off so traffic provably crosses the mixnet.
  • 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.

Project structure

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

Status & roadmap

FIPS is at v0.5.0-dev on the master branch. v0.4.1 has shipped; this development line continues the testing-and-polishing track toward v0.5.0. The core protocol works end-to-end over UDP, TCP, Ethernet, Tor, Nym, and Bluetooth on a global, public test mesh of thousands of nodes. v0.4.0 added the Nym mixnet transport and mDNS LAN discovery alongside the existing Nostr-mediated peer discovery, UDP NAT traversal, peer ACL, and packaging hardening. New wire-format work continues to be staged on the next branch for the subsequent release line.

What works today

  • Spanning-tree construction with greedy coordinate routing.
  • Bloom-filter-guided destination discovery (no flooding, single-path with retry).
  • Two-layer Noise encryption (IK at the link, XK at the session) with periodic hitless rekey for forward secrecy at both layers.
  • Persistent or ephemeral 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, Nym (mixnet), and BLE transports (BLE via L2CAP CoC with per-link MTU negotiation).
  • Nostr-mediated overlay endpoint discovery and UDP hole punching for NAT traversal, plus mDNS LAN discovery for local peers.
  • LAN gateway (fips-gateway) with both outbound (LAN-to-mesh) and inbound (mesh-to-LAN port-forwarding) modes.
  • Peer ACL: per-npub allow / deny admission control at the link layer; opt-in mesh-firewall baseline at fips0 ingress.
  • 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), FreeBSD (.pkg), and Windows (ZIP, service) packaging.
  • Docker-based integration and chaos testing.

Near-term priorities

  • Native API for FIPS-aware applications (npub:port addressing without the IPv6-shim path).
  • Security audit of the cryptographic protocols.

Longer-term

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

License

MIT — see LICENSE.

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