Johnathan Corgan
3a789370b9
A client process opens a flow to a peer's public key on a chosen port and sends and receives datagrams on a file descriptor the daemon hands it. No IPv6 emulation, no TUN device, no DNS: a datagram travels from key to key. The feature is off by default and is not a stable interface. The wire needs no change and gets none. Every FSP data packet has carried a port pair inside its AEAD envelope since v0.2.0, and port 256 is simply the IPv6 shim. What was missing was a way for a program to ask for a port of its own and be handed the traffic. Addressing is the part worth reading twice, because the obvious design is wrong. The x-only public key is the address. An npub is that key written in bech32, so converting between them is a local encoding rather than a lookup or a name service. The 16-byte node address that travels on the wire is the first half of a SHA-256 of the key: it is a truncated hash, it does not invert, and it appears nowhere a client can see. An earlier iteration of this work reported a peer by that hash and could supply a key only sometimes, which is what treating a wire identifier as an identity produces. An accepted flow therefore always knows its peer. The key is captured where the peer is authenticated rather than looked up when a report is rendered: every inbound datagram passes one call site inside a handler that refuses anything whose session is not established, and the responder has already rejected the session unless the claimed address derives from the key it proved. Reaching for the identity cache instead gives a best-effort answer from a structure that evicts. A listener is a descriptor. The daemon writes one message per arrival to it, carrying the new flow's descriptor and the peer's address, so poll, select and epoll work on a listener and accepting is a recvmsg. That is what lets the API be used from a program that already has an event loop, which a command-and-reply listener could not support: an arrival could not be waited on beside anything else. There is no accept command and no reject command. Refusing a flow is closing the descriptor you were handed. The Rust surface mirrors std::net. FipsStream::connect, FipsListener::bind, incoming, accept, io::Result and an errno mapping rather than a bespoke error type. An address is given as an npub, as a key, or as a pair, through one parameter, the way ToSocketAddrs takes several spellings of one thing. Each type holds its descriptor and copies of what setup told it and nothing else, so a stream that outlives its setup connection is not representable. set_nonblocking, AsFd and the four deadline methods carry the names and signatures std::net uses for the same jobs. They were asked for by a user integrating the API with tokio: AsyncFd requires a non-blocking descriptor, and anything receiving from a peer needs a bounded wait. AsFd is the better of the two descriptor accessors, because the borrow cannot outlive the value that owns the descriptor, so a reactor cannot hold a registration for a descriptor that has since been closed and its number reused by the next open. The non-blocking flag is read, modified and written back rather than assigned, since the flag word carries more than that one bit and a caller may have set O_ASYNC. A zero timeout is refused with EINVAL, because the kernel reads a zero timeval as "wait for ever", which inverts what a caller passing zero means; std::net refuses it for the same reason. The two directions are separate options and stay that way. FipsListener gets no timeout methods, matching TcpListener: bounding an accept is set_nonblocking plus the caller's own poll, which the reactor how-to builds. A flow taken from accept is blocking whatever the listener was set to, because the two are separate sockets and the daemon hands over a fresh one. One rule has no counterpart in Berkeley sockets and a client author must know it: the v1 wire carries no half-close, so nothing peer-driven ever closes a flow. A server written to read until the flow ends waits for a signal that cannot arrive, holding a thread and a flow per peer until its process exits. A program decides its own termination, and the example serves one datagram per flow. The tests reach a live daemon rather than a stand-in. Every public item had a unit test against a hand-written stand-in with canned replies, and the five entry points a program actually calls first, connect, connect_from, connect_at, bind and the SOCKET constant, had no coverage of any kind, because the tests that appear to cover them build a Wire over a socket pair and hand it to the private open and hold, so nothing ever resolved a socket path or mapped its errors. examples/native-surface.rs walks all thirty-eight items against a running daemon and reports the number of assertions it made. The count is read from the recorder rather than written as a literal, and the harness asserts the exit status, the completion marker and the count together, so deleting an assertion fails the check rather than quietly shrinking it. Watchdogs turn a hang into a named failure, which several of the walked behaviours would otherwise produce. The shared Docker image is built once for every integration leg, so the new binary is staged at all ten places the existing one is, the interop builder included, which gets a stub because those images exercise the wire between daemon versions and older refs do not carry the example. The platform gating was tested rather than reasoned about: flipping all eleven gates so the native API is excluded leaves the crate compiling clean across the workspace, every target and the profiling feature. The shipped docs tree gains what only the LaTeX manual under design/ had, which is not published with the daemon. A reference entry covers the whole surface: addressing and the port tiers, the Berkeley mapping, every method on FipsAddr, FipsStream, FipsListener and Incoming, the errno table, the ceilings, the four places data disappears with nothing reported, the line protocol and the command reference. The errno table gives names rather than numbers, since the client maps each name onto the libc constant for the platform it was built for and the supported platforms disagree on the numbers. A tutorial side trip stands up two throwaway nodes on one machine, peered over loopback UDP with no TUN and no DNS, then writes a listening program and a connecting program against them; it needs neither the public mesh nor root, because the native path is the one that does not go through the IPv6 adapter. The obligations a client in another language carries are a how-to of their own, since they are a task rather than a description: reading the setup connection with recvmsg, associating a descriptor with the last complete line, telling an empty datagram from a close, and six others. Serving many peers from one poll loop is another, with the whole program, because the straightforward listener spawns a thread per flow and that is wrong at the node's ceiling of 256. The drop causes are a table mapping each of the seven texts DropReason::as_str produces to the counter it increments, with drop_oversize called out as the ninth counter that is not in the table. What a daemon restart costs is a section of its own: every flow and listener ends, descriptors do not survive, there is no resumption, and datagrams sent but not yet forwarded are lost through a window nothing bounds. A stack comparison diagram places the interface against the stack a reader already knows: the same application over HTTP, TLS, TCP, IP and Ethernet on one side, and over its own format, FSP, FMP and a FIPS transport on the other, aligned so each row is one concern. The two columns are not alternatives and are not drawn as such. An unmodified IPv6 program's packets reach fips0, and the adapter hands each one to FSP as a payload, so the left stack runs inside the right one; the left column ends at a fork, eth0 for the ordinary internet and fips0 for the mesh, and an arrow leaves fips0 and runs back up into FSP's input. The row where TCP would be is empty on purpose and names Reliable Object Delivery, which is where that capability is expected to land. ROD is a v2 capability, the box is dashed because none of it exists yet, and the design entry says the part a reader needs most: nothing on the surface anticipates it, so a program written today should assume it does not exist. Both endpoints carry a scheme and a worked port, https://<npub>.fips:443 and fips://<npub>:443, with a footnote saying the two ports are not the same kind of thing, a TCP port inside the tunnel on the left and an FSP port on the right. The fips:// form is a coinage: nothing in the tree parses it, nothing registers the scheme, and the API takes a key and a port as separate arguments rather than a URL. The diagram also says where the right column stops, since FIPS over UDP still rides IP and Ethernet beneath. It appears in fips-concepts.md and fips-ipv6-adapter.md, which were making its argument in prose without a picture, and deliberately not in fips-architecture.md, which already carries the OSI mapping and makes the same point about the transport row. The gateway's control socket moves onto the same bind policy this API uses, which is the one change here that touches deployed behaviour: fips-gateway now tightens /run/fips to 0750. That is unreachable under the packaged deployment, where fips.service has already created the directory at that mode, and reachable for a source build or a container that starts the gateway alone. One changelog entry under Added, describing the released state: what a client opens and reads, the addressing and why the node address is not it, the listener being a descriptor, the std::net shape of the Rust surface, and the one rule Berkeley sockets have no counterpart for. It says in as many words that the wire is unchanged.
FIPS Testing
Integration and simulation test harnesses for FIPS, using Docker containers running the full protocol stack.
Test Harnesses
static/ -- Static Docker Network
Fixed topologies with manual scripts for building, config generation, connectivity tests (ping, iperf), and network impairment (netem). Useful for deterministic debugging and validating specific topology configurations.
| Topology | Nodes | Transport | Description |
|---|---|---|---|
| mesh | 5 | UDP | Sparse mesh, 6 links, multi-hop |
| chain | 5 | UDP | Linear chain, max 4-hop paths |
| rekey | 5 | UDP | Rekey integration test topology |
tor/ -- Tor Transport Integration
End-to-end Tor transport testing with Docker containers running real Tor daemons. Requires internet access for Tor bootstrapping.
| Scenario | Description |
|---|---|
| socks5-outbound | Outbound SOCKS5 connections through Tor to clearnet peer |
| directory-mode | Inbound via HiddenServiceDir onion service (co-located) |
nat/ -- NAT Traversal Lab
Real Docker NAT traversal tests for the Nostr/STUN bootstrap path,
using router containers with iptables-based NAT, a local Nostr relay,
and a local STUN responder.
| Scenario | Description |
|---|---|
| cone | Two NATed peers establish a UDP traversal path |
| symmetric | UDP traversal fails under symmetric NAT, TCP fallback wins |
| lan | Peers on the same LAN prefer local addresses over reflexive |
chaos/ -- Stochastic Simulation
Automated network testing with configurable node counts, topology algorithms (random geometric, Erdos-Renyi, chain, explicit), and fault injection (netem mutation, link flaps, traffic generation, node churn). 20 scenarios covering general stress testing, cost-based parent selection, mixed link technologies (fiber/Bluetooth/WiFi), transport-specific validation (UDP, TCP, Ethernet), and ECN/congestion testing. Scenarios are defined in YAML and executed via a Python harness that manages the full lifecycle: topology generation, Docker orchestration, fault scheduling, log collection, and analysis.
interop/ -- Mixed-Version Interop Harness
On-demand harness that runs an N-node full mesh from a node-spec where
each node can run a different build of the FIPS daemon, then attributes
every FMP/FSP/rekey/connectivity failure to a specific version pair
(same-version vs MIXED). Used to catch interop regressions between
builds, not as a per-commit CI gate; not part of ci-local.sh.
mesh-lab/ -- Mesh Reliability Lab
On-demand harness that runs a chosen integration suite N times under a
configurable host-pressure profile (idle / light / github-runner-
equivalent / heavy via stress-ng), per-container netem impairment,
and optional trace-level RUST_LOG, capturing per-rep diagnostics and a
mechanism-match summary across the run. Used for statistical reliability
characterization of known flake classes under calibrated stress, not as
a per-commit gate; not part of ci-local.sh.
Running CI locally (ci-local.sh)
ci-local.sh runs the full local CI pipeline — build,
clippy, unit tests, and the integration suites (including the chaos
scenarios) — mirroring the GitHub ci.yml integration matrix. Run
./ci-local.sh --help for the full option list and --list for the
available suites. Every run starts with a parity check that verifies the
local suite set covers the same work as the GitHub matrix, per scenario for
chaos and per distro for deb-install; a divergence fails the run. GitHub
runs the same check as its own ci-parity job. --check-parity runs it
alone (see check-ci-parity.sh).
Per-run isolation and the FIPS_CI_RUN_ID override
Every invocation derives a run id and scopes all of its Docker resources to it, so two simultaneous runs on the same host (for example, one per git worktree, or an operator testing by hand while CI is in flight) never collide:
- Compose projects are named
fipsci_<run-id>_<suite>, so container, network, and volume names are all prefixed per run. - Build images are tagged
fips-test:<run-id>andfips-test-app:<run-id>, exported asFIPS_TEST_IMAGE/FIPS_TEST_APP_IMAGE, and every compose file and suite script reads those. The run does not writefips-test:latestat all: a bridge back to that shared mutable name would let a consumer that had been missed keep working while resolving whichever concurrent run wrote the tag last.:lateststays the hand-build name, produced bytesting/scripts/build.sh, and remains the default every consumer falls back to when the variables are unset. - The build context is a per-run copy at
testing/docker-<run-id>/, exported asFIPS_BUILD_CONTEXT. It is absolute because compose resolves a relative build context against the compose file's own directory rather than the working directory.testing/docker/is the hand-run context and a CI run does not write to it. Without this, two runs race on the contents of one directory and either can build a correctly-per-run-tagged image from the other's binaries. - Each parallel chaos child gets a unique, non-overlapping
/24in10.30.x(via the sim--subnetoverride).10.30.xsits outside Docker's default address pool and the fixed-subnet suites'172.xranges, so neither a sibling chaos child nor an auto-assigned network can swallow a pinned subnet.
By default the run id is <short-git-sha>-<random> — the SHA portion
records what code a container is testing, the random suffix keeps
simultaneous runs of the same SHA disjoint. Override it for a
reproducible, attach-by-name debug session:
FIPS_CI_RUN_ID=mydebug ./ci-local.sh --only static-mesh
# containers are named fipsci_mydebug_static_fips-node-a, etc.
Preemption-safety and exit codes
ci-local.sh is safe to cancel mid-run. A signal trap tears down every
compose project the run started (not just the current suite) and reaps
any in-flight parallel chaos children, bounded by a timeout so a stuck
compose down cannot wedge the trap. Exit codes distinguish a cancelled
run from a failing one:
| Code | Meaning |
|---|---|
0 |
all stages passed |
1 |
one or more stages failed |
130 |
interrupted by SIGINT — cancelled, not a failure |
143 |
terminated by SIGTERM — cancelled, not a failure |
A preempting CI worker (the push-triggered, CI-gated build pipeline that
kills an in-flight run when a newer same-branch tip arrives) maps
130/143 → cancelled (discard, do not record a failing commit), 0
→ green, any other non-zero → red.
Cleaning up leftover resources
Every CI-created container, network, and volume carries the label
com.corganlabs.fips-ci=1. If a run is hard-killed (SIGKILL, OOM, crash)
and leaves resources behind, reap them with:
./ci-local.sh --reap # or: ./ci-cleanup.sh
ci-cleanup.sh force-removes everything bearing the CI
label or a fipsci_ compose-project prefix; it is safe to run when there
is nothing to reap and safe to run repeatedly. Pass --project-prefix to
scope the sweep to a single run.
It also removes the chaos simulation's leftover host-namespace veth
interfaces (vh…a/vh…b), the one resource it touches that is neither a
docker object nor labelled — a host interface can carry neither a label
nor a compose project, so it is matched by name shape alone. That makes
the reach here asymmetric with everything above, and worth stating
plainly:
- A bare
chaos.shrun's containers survive a broad reap. Its compose project is notfipsci_, and the simulation labels only the network, not the services. - A bare
chaos.shrun's veth interfaces do not. An unscoped reap deletes them while they are in use, severing the Ethernet links of a live simulation and leaving its containers running.
So do not run a broad --reap while a bare simulation is up. Scope the
interface sweep with --veth-suffixes (which is what ci-local.sh's own
teardown passes) or wait for the simulation to finish. --project-prefix
does not help here: it scopes only the compose-project sweep.