Files
fips/testing/nat
Johnathan Corgan e4a854f6b0 Stop concurrent local CI runs from clobbering each other's containers
Two runs on one host destroyed each other's containers, producing
mid-test "No such container" failures that look like real defects. The
automated builder runs a full local CI on the same box every few minutes,
so the machine is contended almost always and this has red-ed both a hand
run and an automated gate.

Two independent causes are fixed here. Container names were hardcoded, and
docker names are global rather than scoped by compose project, so two runs
collided on the same name; every name now takes an optional suffix that
the harness sets from the run id. And the cleanup sweep matched a label
shared by every run, so one run's teardown force-removed another's
containers; resources now also carry a per-run label and the sweep can be
narrowed to it.

A third hazard turned up that was not in the original report: the sidecar
suite passes explicit compose project names, which override the run-scoped
project and put it outside the shared prefix entirely. Its project names,
network, and derived container references are now scoped too.

Both are default-off. With the suffix unset, names render exactly as they
do today and a bare compose invocation is unchanged, which is what keeps
the hosted CI and the documentation correct. A cleanup run with no run id
still reaps everything, which is what a manual "clear the box" wants.

The literal-name sweep was not sufficient: six scripts build container
names dynamically from node labels, and two suites create their own
containers outside compose. Those are handled at their construction sites.

Verified: syntax check on all modified scripts; compose validation on
every modified file with the suffix both set and unset; and a synthetic
two-run reproduction that shows the old cleanup destroying a bystander run
and the new one leaving it alone.

Known gap: subnets are still hardcoded, so two concurrent full runs will
still collide on address-pool overlap. That fix reaches into topology
configs, chaos scenarios, diagrams and production source, so it is left
for its own change rather than half-done here.
2026-07-19 06:41:25 +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