Files
fips/testing/nat
Johnathan Corgan 37c2973e2f Test infrastructure overhaul: gateway robustness + full CI coverage
Single combined commit covering five interlocking pieces of test and
CI work that landed during the v0.3.0-prep cycle.

## fips-gateway robustness

- src/bin/fips-gateway.rs DNS upstream probe converted from a 3-second
  hard-fail to a bounded retry loop (5 attempts × 1s timeout, 1s sleep
  between attempts; ~10s worst case). Covers the cold-boot race where
  the daemon's TUN is up but the DNS responder at [::1]:5354 is still
  binding. Each failed attempt logs at INFO. In production the binary's
  retry is the live recovery mechanism; with retry it recovers silently
  instead of relying on Restart=on-failure (~5s blip + spurious ERROR
  per cycle).
- packaging/debian/fips-gateway.service `ExecStartPre` now waits up to
  30 seconds for the daemon's `fips0` TUN to appear before exec'ing
  the gateway binary. Eliminates the cold-boot race where the gateway
  exits with `fips0 interface not found` and recovers via
  `Restart=on-failure`, producing a 5-second blip and a spurious error
  log per restart cycle.
- testing/docker/entrypoint.sh gateway-mode waits up to 30s for the
  daemon's DNS responder to bind [::1]:5354 (probes once per second
  with `dig @::1 -p 5354 ... test.fips`) before exec'ing fips-gateway.
  Belt-and-suspenders with the binary's own retry: in CI we want
  deterministic startup ordering. On timeout, fall through so the
  binary's probe reports the definitive error.

## Test infrastructure DNS bind migration to ::1

After session 359's daemon DNS-bind default flipped from `127.0.0.1`
to `::1` (the production fix for ISSUE-2026-0002), the static-test
infrastructure was carrying a stale workaround that overrode the
default back to IPv4 loopback. The fips-gateway integration test
exposed the divergence: the gateway probes its DNS upstream at
`[::1]:5354` (production default) while the daemon was binding
`127.0.0.1:5354` from the template override — IPv6-explicit sockets
do not accept v4-mapped traffic, so the upstream probe exhausted
retries and the gateway exited.

- Drop the explicit `bind_addr: "127.0.0.1"` line from every test
  config that emits it: testing/static/configs/node.template.yaml,
  testing/chaos/configs/node.template.yaml, the sidecar heredoc in
  testing/docker/entrypoint.sh, testing/acl-allowlist/generate-configs.sh
  (six per-node blocks), testing/nat/scripts/generate-configs.sh, and
  the four tor templates under testing/tor/. Daemon picks up its
  production `::1` default.
- Flip the dnsmasq forwarder for `.fips` in testing/docker/Dockerfile
  from `127.0.0.1#5354` to `::1#5354` so dnsmasq on the shared test
  image continues to reach the daemon. Template and Dockerfile must
  move together since most static suites resolve `<npub>.fips` via
  the test-image dnsmasq.

## rekey-accept-off integration variant + UDP unit test

- New `rekey-accept-off` topology and docker-compose profile under
  testing/static/. 2-node variant where node-b runs with
  `udp.accept_connections: false`. Pins the regression class that
  ISSUE-2026-0004 fixed (cross-connection winner's rekey msg1 was
  being filtered by the accept_connections gate, breaking rekey).
- testing/static/scripts/rekey-test.sh accepts REKEY_TOPOLOGY and
  REKEY_ACCEPT_OFF_NODES env vars; its inject-config subcommand
  applies the per-node `udp.accept_connections: false` edit, and
  the test asserts no sustained "Dual rekey initiation" log lines.
- New UDP variant of `should_admit_msg1` admit-rekey unit test in
  src/node/tests/handshake.rs.

## ci-local.sh full integration coverage

- New runner functions and dispatcher entries for `acl-allowlist`,
  `nat-cone` / `nat-symmetric` / `nat-lan`, `rekey-accept-off`,
  `dns-resolver`, `deb-install`. Each integrates with the existing
  summary tracking via `record`.
- New `--with-tor` flag (off by default) gates `tor-socks5-outbound`
  and `tor-directory-mode` runners. Tor stays opt-in because both
  harnesses depend on the live Tor network and would introduce a
  flake source unrelated to the FIPS code.
- New suite arrays (`ACL_SUITES`, `NAT_SUITES`, `DNS_RESOLVER_SUITES`,
  `DEB_INSTALL_SUITES`, `TOR_SUITES`) drive both the default sweep
  and `--list` output.
- `run_suite` extended to accept the new suite names for `--only`
  invocations.

## GitHub CI matrix expansions

- `gateway` matrix entry runs testing/static/scripts/gateway-test.sh
  against the existing docker-compose `gateway` profile.
- `rekey-accept-off` matrix entry exercises the new topology with
  REKEY_ACCEPT_OFF_NODES=b.
- `deb-install` matrix (debian12 + ubuntu24 + ubuntu26) runs
  testing/deb-install/test.sh with privileged systemd containers.
  ~5-7 min cold cache, ~2 min warm per distro. Self-contained: builds
  its own .deb in a Debian 12 cargo-deb builder image; does not
  depend on the build job's pre-built artifact.
- `dns-resolver` matrix entry runs the full 13-scenario harness
  (per-distro systemd resolver-backend tests + real-fips end-to-end
  scenarios) in a single job. Pins the production DNS bind path that
  ISSUE-2026-0002 lived in. ~7-12 min warm, ~12-15 min cold.

Verified locally: full `bash testing/ci-local.sh` sweep passes,
including 5/5 deb-install distros and all 13 dns-resolver scenarios.
Tor-inclusive sweep (`--with-tor`) verified in a follow-up run.
2026-04-30 10:24:32 +00:00
..

NAT Lab Harness

Real Docker-based NAT traversal integration tests for the mainline FIPS Nostr/STUN bootstrap path.

This harness spins up:

  • two FIPS nodes
  • a local Nostr relay
  • a local STUN server
  • one or two Linux router containers performing NAT with iptables

For the NAT scenarios, the node LAN interfaces are not attached to Docker bridge networks. The harness creates explicit veth pairs and moves them into the node and router namespaces after docker compose up so every packet must traverse the router namespace.

It covers three scenarios:

  • cone: both peers behind explicit namespace/veth full-cone emulation, UDP traversal succeeds
  • symmetric: both peers behind symmetric-style NAT, UDP traversal fails, TCP fallback succeeds
  • lan: both peers share a LAN subnet, LAN targets are preferred over reflexive addresses

NAT model notes

The harness does not rely on plain Docker MASQUERADE for the cone case.

  • cone
    • uses explicit full-cone emulation in the router namespace
    • outbound UDP is SNATed to the router WAN address while preserving the source port
    • inbound UDP to the router WAN address is DNATed back to the single LAN host regardless of remote source
  • symmetric
    • uses UDP MASQUERADE --random-fully
    • outbound mappings may be port-randomized and are only reopened by matching conntrack state

This distinction matters because plain MASQUERADE is convenient source NAT, but it does not by itself model the "accept from any remote once mapped" behavior expected from a full-cone NAT.

Prerequisites

  • Docker with Compose support
  • locally built fips-test:latest

Build the test image with:

./testing/scripts/build.sh

Run

Run all scenarios:

./testing/nat/scripts/nat-test.sh

Run one scenario:

./testing/nat/scripts/nat-test.sh cone
./testing/nat/scripts/nat-test.sh symmetric
./testing/nat/scripts/nat-test.sh lan

Layout

  • docker-compose.yml
    • relay/STUN/WAN topology plus container definitions
  • node/
    • node bootstrap wrapper that waits for the injected veth interface
  • router/
    • NAT router image and iptables setup
  • stun/
    • minimal STUN binding responder
  • relay/
    • local strfry config
  • scripts/generate-configs.sh
    • derives ephemeral identities and writes per-scenario FIPS configs
  • scripts/setup-topology.sh
    • injects and configures the NAT LAN veth pairs in the container namespaces
  • scripts/nat-test.sh
    • boots the lab, waits for convergence, and asserts the resulting path

Assertions

  • cone

    • both nodes connect
    • connected transport is UDP
    • active link remote addresses are on the WAN NAT subnet
  • symmetric

    • NAT bootstrap does not establish a UDP link
    • fallback converges
    • connected transport is TCP via router-published WAN addresses
  • lan

    • both nodes connect
    • connected transport is UDP
    • active link remote addresses stay on the shared LAN subnet