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Johnathan Corgan
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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.
149 lines
7.8 KiB
Markdown
149 lines
7.8 KiB
Markdown
# Native Datagram API
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The native datagram API lets a local program move bytes between two public keys
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over FSP, with no IPv6 emulation and no TUN device in the path. A program calls
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`connect` for a flow to a public key and a port, or `bind` for a port to receive
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flows on, and from then on uses ordinary socket calls.
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This document explains what the interface is for and where its edges are. For
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the surface itself — every type, method, errno and command — see
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[../reference/native-api.md](../reference/native-api.md). For the steps to enable
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it and write a program, see
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[../how-to/use-the-native-datagram-api.md](../how-to/use-the-native-datagram-api.md).
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## Where it sits
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The two endpoints at the top are the same node reached two ways. **The
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`fips://` form is illustrative**: no code in this repository parses it, nothing
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registers the scheme, and the API takes a key and a port as separate arguments
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rather than a URL. It is drawn because it is the shape an address takes on that
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side, against a `.fips` name the adapter's DNS really does resolve.
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Read row by row, the native path replaces three layers and declines to replace a
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fourth. FSP takes TLS's place and anchors trust in the key rather than in a
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certificate authority. FMP takes IPv6's place and routes by spanning tree and
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bloom filter rather than by address prefix, with the address derived from the
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key. The transport layer takes the medium's place and can be several media at
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once.
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**There is nothing where TCP was**, and on the native path that is the single
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most consequential row today. No acknowledgement, no retransmission, no ordering
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and no flow control: a program that needs any of them builds it into its own
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payload.
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That row is marked **ROD — Reliable Object Delivery**, which is where the
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capability is expected to land. ROD is a v2 capability and is not in v1; it may
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be pulled forward. Until it is, treat the row as empty and design around it,
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because a program written against a reliability layer that is not there yet
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fails in the ways this document's "not a reliability layer" section describes.
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**The two paths are not alternatives at the bottom.** They converge. An
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unmodified IPv6 program does not stop at a wire: its packets reach `fips0`, and
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the adapter hands each one to FSP as a payload. That is the arrow running up the
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middle of the diagram, and it is why the left stack is drawn ending at an
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interface rather than at Ethernet.
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So the whole left column runs *inside* the right one. **TCP included** — which
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is the practical answer to the empty row above it. A program that needs a
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reliable ordered stream over the mesh already has one: run it over `fips0` and
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let TCP do what TCP does, inside FSP's encryption. What the native API offers
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instead is the same mesh with four layers of machinery removed, for a program
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willing to do without them.
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The bottom of the diagram is not always the bottom of the stack either. When
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FIPS overlays an existing network its transport is UDP, which still rides IP and
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Ethernet beneath; when the mesh *is* the network, a transport sits on a link
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directly.
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## What it is instead of
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The fastest way to place the interface is by contrast with the TUN device, which
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is the other way a program gets FIPS traffic.
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| | TUN interface | Native datagram API |
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| --- | ------------- | ------------------- |
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| Addressing | IPv6 address | public key, written as an npub |
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| Name resolution | DNS over the mesh | none: the program supplies the key |
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| Kernel object | TUN device, routes | a `FipsStream` per peer |
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| Encapsulation | IPv6 emulated over FSP | FSP port pair, no IP layer |
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| Program sees | an IP network | a `FipsStream` |
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| Privilege | `CAP_NET_ADMIN` to create the device | membership of group `fips` |
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| Demultiplexing | by address and port | by flow, one stream each |
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**The IPv6 emulation is not removed by this interface.** It continues to run
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beside it on FSP port 256, which is why that port and the tier around it are
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refused to a program. What the native API removes is a program's *dependence* on
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it: a program that wants to move bytes between two known public keys no longer
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has to acquire an IPv6 address, resolve a name, and hand its payload to a
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protocol stack that will encapsulate it again.
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Both paths reach the same place. A native datagram and an emulated IPv6 packet
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are both FSP payloads with a port pair, carried in the same encrypted session to
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the same peer. The difference is entirely on the local side of the daemon.
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## Status
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**The wire is connected**: a datagram sent on a flow leaves the node over FSP,
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and one arriving on a held port reaches its flow.
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**The interface around it is experimental.** It is not versioned, it has no
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compatibility promise, and three of its five commands exist only to let the
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daemon's own checks drive the receive path without a peer. It is Linux, FreeBSD
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and macOS only — Windows cannot be supported, as it has no `SCM_RIGHTS` — and it
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is off by default.
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## What this is not
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**Not a stable interface.** It is an experiment on the v1 wire. Names, fields,
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reply shapes and the command set may change without a deprecation cycle.
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**Not the v2 process API.** The v2 external process API is a separate and later
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design, which retires ports entirely in favour of a listener, connection and
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stream model. Nothing here governs it and nothing there governs this. The one
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thing this interface takes from that work is the FSP port tiers, because port
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256 already carries the IPv6 shim on the deployed wire and a new service must not
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collide with it.
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**Not a reliability layer.** There is no acknowledgement, no retransmission, no
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ordering guarantee and no flow control between the two ends. A datagram is
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carried or it is dropped. Some drops are counted inside the daemon and none are
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reported to a program for real traffic. A program that needs delivery guarantees
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builds them itself, on top, in the payload — or runs over `fips0` and lets TCP
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provide them.
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Reliable Object Delivery (ROD) is the v2 capability intended to fill this gap,
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and it may be pulled forward into v1. **Nothing here anticipates it**: no field,
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reply shape or command on this surface is reserved for it, and a program written
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today should assume it does not exist.
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**Not an authorization boundary.** The socket's group ownership is the whole of
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the access control. Any process that can open it can send as this node's identity
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and can receive mesh traffic on any port it can claim, and there is no per-program
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separation beyond the port registry. Because the descriptor carries the flow, a
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process handed one over `SCM_RIGHTS` can send as this node on that flow without
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ever opening the socket. See
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[../reference/security.md](../reference/security.md#native-datagram-api).
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**Not multi-tenant.** `max_flows` is node-wide with no per-program share, so one
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program can exhaust it, and every other program then sees `EMFILE` on `connect`
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and silent drops on its listeners.
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**Not a connection in the TCP sense.** A successful `connect` is a local
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registration and contacts no peer. There is no handshake, no keepalive and no
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notification that a peer went away. A flow ends when its descriptor closes, and
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in no other way. In particular **a peer cannot end your flow: it has no close to
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send.** That single fact shapes every program written against this interface,
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and the consequences are drawn out in
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[../how-to/use-the-native-datagram-api.md](../how-to/use-the-native-datagram-api.md#four-things-that-will-bite-you).
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## See also
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- [fips-session-layer.md](fips-session-layer.md) — FSP, which carries the
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datagrams and owns the port pair
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- [fips-ipv6-adapter.md](fips-ipv6-adapter.md) — the other consumer of FSP, and
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what this interface is an alternative to
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- [../reference/native-api.md](../reference/native-api.md) — the surface, the
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line protocol and the command reference
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