Files
fips/CONTRIBUTING.md
Johnathan Corgan 6a564e26ac Prepare the v0.5.0 release content
Everything the release needs except the version number, which stays at
0.5.0-dev until the tag.

The changelog entry covers only the work that is new on this line. The
point release's forty-six entries arrived under their own heading with the
forward merge and are left alone; the twenty that remained are regrouped by
topic and eight more added for changes no entry covered. Three of those
eight matter to someone upgrading. Five root modules and four re-exports
left the public library surface and Node::connections narrowed, none of it
recorded anywhere; the entry names what to use instead and distinguishes
the removed connection-phase enum from the Noise type of the same name,
which is a different type that still exists. Tracing targets moved, so an
existing RUST_LOG filter stops matching rather than erroring. And the
handshake resend interval key no longer governs the first resend, which is
now a constant, though it still governs later ones.

Seven more entries cover the work that landed after the first content pass
was written: the experimental native datagram API, the fipsctl probe
diagnostic, per-instance transport addressing, the app-owned UDP socket
seam, and the connect, disconnect and path-MTU fixes. The four bug fixes
among them all reach the deployed line, so the release notes no longer
claim this release carries exactly one fix for a shipped bug; it carries
four.

There is no security section, because after the split every security entry
belongs to the point release. The release notes say so plainly rather than
leaving a reader upgrading across both releases to conclude this one
carries no security work.

The notes are organized by audience, since the release spans OpenWrt
routers, embedders, FreeBSD, and the existing platforms, and a single list
serves none of them. The native datagram API is given a section of its own
rather than folded into the embedding seam: it is a client-facing API
rather than a way to host a node, and its one rule with no Berkeley-socket
counterpart, that the v1 wire carries no half-close, needs to be somewhere
a client author will read it. FreeBSD is advertised as supported on x86_64
only, stated wherever the platform appears. Android is advertised as an
embedding seam and not as a supported platform: a compile-gated library
surface with no artifact and no host application guide.

The configuration table rename is carried through every shipped file that
taught the old spelling: nine documentation files, the OpenWrt sample
config and a test generator, twenty-two sites in all. Guides written this
same cycle were among them, which is how the omission was found. The
documentation that arrived with the native API was checked for the same
omission and was already clean. The compatibility tests keep the old
spelling deliberately, since they exist to test the fold.

The changelog section is the fold of master's [Unreleased], not a snapshot
of it. An earlier version of this commit took a copy that then drifted, so
each section ended up holding a bullet the other did not and re-folding
them would have picked a winner silently. Both causes were fixed on master
instead — the NixOS module had never been recorded there, and the
pre-release batch of fixes was new — so [Unreleased] is a strict superset
and this is a copy rather than a merge. [0.5.0] carries all forty-six
bullets byte for byte, [Unreleased] is empty, and [0.4.2] is untouched,
checked by hashing it against master's copy.

The BLE work landed after the content pass and gets one summary entry in
the changelog and one section in the release notes rather than nine
bullets: the ble_available gate replacing target_os = "linux",
packet-boundary recovery for stream-oriented backends, peer recognition by
node identity instead of a rotating link address, the L2CAP PSM moving
into the backend seam and onto the advertisement, the embedder-supplied
Android radio, bounded probe retry, and inbound handshakes moved off the
accept loop.

The two release-notes copies no longer share their link paths. Relative
links resolve from one directory only, so the seven written for
docs/releases/ all 404ed from the root copy. The root copy now uses paths
from the repository root and the versioned copy keeps the ../ form; both
sets were resolved against the tree. The same two links are broken the
same way in the v0.4.0 through v0.4.2 notes, left as shipped history.

The contributor tallies are re-derived against maint..HEAD rather than
adjusted: twenty commits from outside the project and 171 from me, with
Arjen at fifteen and fr34aky at two. An earlier count of twelve and 138
was carried from a measurement taken three days before this content was
written, and the BLE branch widened the gap after it. Arjen's NixOS flake
module, the UDP sin6_scope_id fix and most of the BLE rework were
uncredited, as was fr34aky's L2CAP PSM seam. They want one last re-derive
at tag time if anything lands before the tag.

A sweep of all 99 tracked markdown files against the tree corrected
fifty-three of them. Four told the reader to run a build.sh that does not
exist; the only harness builder is testing/scripts/build.sh. The BLE build
prerequisites were described as optional on the strength of a probe that
build.rs does not perform, and bluez was named a build prerequisite when
libdbus-sys asks only for libdbus-1-dev and pkg-config and bluez is the
runtime daemon. Link cost is the primary sort key in next-hop ranking, not
reserved for future use; Ethernet runs on macOS as well as Linux; the BLE
MTU is the L2CAP CoC MTU rather than a negotiated ATT_MTU; effective
Ethernet MTU is 1497; the LAN discovery subsystem is src/mdns and eight
citations still named a src/discovery that never existed here. The
connectivity states in three tutorials were invented, and their jq filters
matched nothing including healthy peers. One command filtered on a literal
fd97: address prefix, which only the first byte of fixes, so it returned
empty for all but one reader in 256 and every later step using the
variable failed silently. transports.tor.advertise_on_nostr was
undocumented despite being validated against node.rendezvous.nostr.enabled.

The transport design document gains the BLE section it never had, written
from the source: the backend cascade and its compile_error tripwire, the
platform gate, the PSM advertisement wire layout and the byte budget that
forces a 16-bit service-data key, and the probe and admission bounds.

Three source files carried the same class of staleness and are corrected
with the documentation: the OpenWrt ipk usage line and Makefile error text
both named a packaging/openwrt that does not exist, and chaos.sh parsed
--subnet without listing it.

Folded in with the content commit, having been prepared alongside it:

The three GitHub Action pins that had gone stale. Every third-party
action is pinned to a commit SHA, nothing reports that a pin has aged,
and re-resolving all ten against their tags found dorny/test-reporter@v2,
taiki-e/install-action@v2 and vmactions/freebsd-vm@v1 had moved. The
three install-action@nextest references stay unpinned, since that action
reads the tool to install from the ref name. check-action-pins.sh passes
at 75 references and all nine workflow files parse.

The lockfile refresh, which is the mutating half of the dependency sweep.
Thirty-six packages move to their latest semver-compatible versions and
every one is transitive; nothing declared in Cargo.toml changes version.
No advisory forces any of them. It was taken before the validation
battery, because a gate run against a lockfile that later moves proves
nothing about what ships.

The sha2 0.10 to 0.11, hkdf 0.12 to 0.13 and bech32 0.11 to 0.12 majors,
three of the four deferred at v0.4.0 for change surface rather than
security. All three land with no source change. sha2 and hkdf must move
together, since both depend on digest 0.11, and neither changes an
algorithm. That matters because the chaining-key KDF in the Noise
handshake is built on Hkdf::<Sha256>, where an output change would be a
wire break rather than a compile error; no known-answer vectors exist for
that path, so the wire-compatibility gate is what covers it. secp256k1
0.31 is deliberately absent, since nostr's own requirement would leave
two copies of the ECC library in the tree.

The README support matrix, rebuilt as one feature table broken out by
Linux variety. A single Linux column hid that Debian, Ubuntu, Arch and
NixOS are one glibc build differing in packaging, that OpenWrt is musl
and drops BLE, and that Android is not a daemon platform. Transport rows
sort by how many platforms carry them. A Native API row reads its
platform set from the cfg gates. The installer row becomes a package
format row naming the artifact, and only the .deb is exercised per
release.

Four changelog and release-note gaps the BLE re-walk found: a Bluetooth
LE bullet stranded inside the released 0.4.2 section, a missing Fixed
entry for the scan and probe loop counting a pool-refused connection as
an established link, the unnamed embedder call that installs an
application-owned radio, and the fact that stopping the transport now
stops scanning as well as advertising.

Three release-document gaps found walking the unsurveyed commits: the UDP
reuse-flag fix stated in the direction opposite to the one it was made,
with the silent second-daemon bind it prevents left unsaid; the corrected
native-API socket paragraph carried into both release-note copies, which
still named SOCK_SEQPACKET on FreeBSD and two kernels where three are
handled; and the coordinate-cache hardening, which shipped with no text
anywhere despite adding four operator-visible status fields. That last
entry states plainly that the checks are mitigations and not a closure,
since the coordinate is still not authenticated.

Also folded in, the documentation pass that followed the content commit:

A stage-pipeline diagram for the probe, embedded in the fipsctl
reference under the five-stage list. It draws the five stages left to
right with each stage's failure reasons below it, and the bypass that
skips both lookup stages when the coordinates are cached or the target
is a direct peer. Its branches come from the probe state machine rather
than from the report, so the path stage is drawn as the one failure that
does not stop the probe.

A rewrite of the README's "What FIPS does" section. It now opens with
what a machine running FIPS gets, rather than with the two deployment
modes, and gives the self-organizing and permissionless property its own
paragraph since it holds for both modes.

A regrouping of the README's feature list into the mesh, getting traffic
onto it, and running a node, with a bullet added for the native datagram
API, which had none despite sitting in the support matrix. The Quick
start now leads with the released packages rather than a source build.
It also fixes a real defect: the package enables fips.service and
fips-dns.service and starts neither on a fresh install, so .fips name
resolution was silently dead until the next reboot and neither page said
to start the service.

A rewrite of the release notes. They opened with seven subsections of
upgrade caveats and reached the first feature two hundred lines in; they
now open with a summary of the release and elaborate below it in the
same order. Android is stated as supported through an embedded crate
rather than as a standalone daemon, consistently across all three
documents. The OpenWrt pair is corrected: it is 802.11s between routers
with FIPS supplying encryption, authentication and routing, plus a
convention of an open !FIPS SSID a client joins over WiFi, not meshing
over a router's own radios. The probe's path output is described as the
least-common-ancestor walk, which is the worst-case fallback route
rather than the route a packet takes. Detail that did not change what a
reader does was cut from the notes and kept in the changelog.
2026-08-30 10:42:59 +00:00

11 KiB

Contributing to FIPS

FIPS is a mesh routing protocol for Nostr identities over arbitrary transports. The architecture is layered, top to bottom:

  • IPv6 TUN compatibility layer — presents the mesh as a local network interface (fips0) so unmodified applications can use it. Applications send IPv6 packets to fd00::/8 addresses derived from Nostr pubkeys; the daemon converts between IPv6 packets and FSP datagrams.
  • FSP (FIPS Session Protocol) — end-to-end encrypted sessions between identities, with periodic rekey.
  • FMP (FIPS Mesh Protocol) — peer management, spanning tree, bloom filters, routing and forwarding, and link encryption.
  • Transport — the actual wire: UDP, TCP, Tor, Bluetooth LE, Ethernet, and so on. Each transport plugs into FMP via a trait.

Most non-trivial changes affect behavior visible across the mesh — how nodes find each other, how packets route, how sessions rekey, how peers recover from failure. A single-node cargo test run is necessary but not sufficient for that class of change; the integration harness in testing/ is where regressions actually surface. This document covers the workflow assuming that context. Protocol depth lives in docs/design/.

Quick start

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

The pinned toolchain in rust-toolchain.toml is used for deterministic builds. On Linux, a source build requires libclang (sudo apt install libclang-dev on Debian/Ubuntu): the LAN gateway's nftables bindings are generated by bindgen at build time and fail without it. BLE compiles on every glibc Linux target and on Android, and is excluded on musl; on glibc Linux libdbus-1-dev and pkg-config are hard build prerequisites, and without them the build fails inside libdbus-sys rather than skipping BLE. bluez itself is needed only at runtime.

On Nix, nix develop provides the pinned toolchain and all of these build prerequisites without any manual install; see the Nix / NixOS section of packaging/README.md.

For multi-node integration runs, Docker is required. The harness under testing/ starts containerized topologies and exercises real mesh behavior; see testing/README.md for the suite catalog.

For a guided first-run that joins the public test mesh, see docs/tutorials/join-the-test-mesh.md. Pointing your local daemon at a test-* node is the cheapest way to dogfood a change end-to-end before opening a PR.

Choosing a branch to target

FIPS uses three long-lived branches, each a superset of the previous:

  • maint — bug fixes for the latest released version.
  • master — compatible work for the next feature release.
  • next — wire-format-breaking and API-breaking work, staged for the next forklift release.

Pick the branch that matches the scope of your change:

Your change Target
Bug fix in a feature that shipped in the latest release maint
Bug fix in code added on master since the last release master
Bug fix in next-only code (wire-format-breaking work) next
New feature, no wire-format or API break master
Wire-format-breaking or API-breaking change next
Documentation, CI, contributor-facing changes maint if they apply to released material, else master

When in doubt, ask in the issue. The maintainer can retarget if needed. The full release workflow, version conventions, and merge-direction rationale are in docs/branching.md.

Reporting bugs

Search open issues before filing a new one — duplicates are common in a young project.

When you open a bug report, please include:

  • FIPS version (fipsctl --version)
  • Rust toolchain version (rustc --version)
  • OS / distro (Linux distro + kernel, or macOS / Windows version)
  • What you expected to happen — your mental model of the behavior, ideally referencing the relevant docs or config field.
  • What actually happened — the observed behavior, including the surprise.
  • Reproduction steps — minimal and deterministic if you can. Multi-node bugs should include the topology and per-node config excerpts.
  • Evidence — relevant log excerpts (journalctl -u fips or stdout with RUST_LOG=info or debug), fipsctl show output if relevant (peers, links, status), and any visible mesh state.

One issue per bug. Don't bundle unrelated symptoms even if you suspect they share a root cause — the maintainer will link them if they turn out to be related.

Submitting pull requests

Scope discipline

Every PR should make one logical change. The reviewer should be able to read the whole diff and trace every line back to the PR's stated purpose.

  • No drive-by reformatting of unrelated files.
  • No unrelated refactors folded into a bug fix or a feature PR.
  • No "while I was in there" cleanups in files outside the change's natural footprint. Send them as separate PRs; they'll usually land faster on their own.
  • Pre-existing lint warnings in files you didn't touch are not yours to fix in this PR.

Required before opening any PR

Run these locally and confirm they all pass:

cargo fmt --check
cargo build
cargo clippy --all-targets --all-features -- -D warnings
cargo clippy --all-targets -- -D warnings
cargo test

CI runs clippy twice, once with --all-features and once with the default feature set, because an optional feature means two source trees and each pass lints only one of them. Run both locally.

fmt and clippy -D warnings are CI gates — PRs with formatting drift or new clippy warnings will fail CI and be sent back.

Then run the integration suite that exercises your change:

./testing/ci-local.sh --only <suite>

See testing/README.md for the available suites and what each covers. Routing, discovery, rekey, NAT, gateway, and transport changes all have specific suites; pick the narrowest one that touches your code path.

Recommended before opening: the full local CI run.

./testing/ci-local.sh

This is the same matrix that runs on GitHub Actions. Catching a regression locally is much cheaper than catching it in CI.

Self-review against the project review checklist

The 13-criteria checklist the maintainer runs on every incoming PR is published at PR-REVIEW.md. Run your own change through it before opening — or hand the document to your coding agent with "review my branch against this checklist" and let it do the pass. The checklist covers PR hygiene (body, commit shape, base freshness), diff content (does the change do what the description says, does it fit the codebase as a natural extension), and cross-cutting concerns (tests, docs, dependencies, security, contributor-conventional Rust patterns).

This is the first thing the maintainer does on any submission, so running it yourself saves a review round trip.

Additional requirements for feature PRs

  • New CI coverage. Features added without a test that exercises them won't be reviewed. Either extend an existing integration suite or add a new one under testing/. Coverage of just the happy path is fine for an initial PR; edge cases can land as follow-ups.
  • Documentation updated alongside the code. Protocol changes update the relevant docs/design/ page. Config changes update the operator-facing docs in docs/ and the reference config. Behavior visible to operators updates README.md and any tutorial it touches.

Additional requirements for bug-fix PRs

  • A regression test where practical. If a regression test isn't tractable (some bugs only surface under timing or scale that's hard to encode), say so in the PR description with a one-paragraph explanation.
  • Commit message references the bug: the symptom, the root cause in one sentence, and the fix shape.

Merge mechanics

PRs are merged via squash-merge. One logical change per PR becomes one commit on the destination branch, which keeps git bisect useful across the integration suite. Your in-PR commit history doesn't matter for the final landed history — the maintainer rewrites the commit message at merge time.

AI coding assistant policy

Use of AI coding assistants (Claude Code, Copilot, Cursor, Aider, and similar) in preparing a contribution is welcome. These tools are force multipliers and we have no objection in principle to their use in writing code, tests, documentation, or PR descriptions.

What we require is that the contributor does a thorough manual review and editorial pass over the output before submission. Concretely:

  • Verify that the code does what it claims, not just that it compiles.
  • Verify that any tests the agent wrote actually test something useful, not just that they pass.
  • Verify that any documentation matches the behavior.
  • Spot-check the diff for nothing-surprising: no unrelated files modified, no fabricated APIs, no references to symbols that don't exist, no version bumps you didn't intend, no churn outside the change's natural footprint.
  • Be ready to discuss the design choices in the PR as if you wrote every line, because for the purposes of accountability you did.

The coding agent is a tool. The contributor is the author of record and is accountable for whatever they submit. PRs are reviewed on what they contain, not on who or what wrote them.

Review effort scales with submission effort. A submission that shows signs of being unreviewed agent output — irrelevant edits scattered across the tree, hallucinated function names, mismatched test/behavior pairs, fabricated API references, ChatGPT-style summary prose in comments — will receive an AI-coding-agent reply in turn, without human review. If you want a human reviewer's attention, do the editorial pass yourself first.

Repeated submissions of unreviewed AI output will result in the contributor being asked to step back and may result in account restrictions.

Where the conversation happens

  • GitHub issues — bugs, feature requests, design discussions that don't fit on a specific PR.
  • GitHub PRs — design discussion specific to a change in flight. Comment threads on the diff are the right place to push back on a decision.
  • fips.network — community page, podcast, and the project's Nostr account. Broader project conversation and announcements happen here.

For implementation questions specific to your PR, ask in the PR itself. For design or roadmap questions that don't have a clear PR home yet, file a GitHub issue with the design label.

Further reading