Files
fips/testing/static
Johnathan Corgan 364fed7c07 Probe the gateway's inbound forwards with no mapping and assert the rewrite
The inbound port-forward probes ran while the DNS mapping to gw-server
from Phase 4 was still live. Each mapping installs an SNAT rule matching
only the mesh address, ahead of the LAN masquerade, so that rule took
gw-server's inbound flows and the probes passed whether or not the LAN
masquerade worked. The probes also passed on any response, so a flow
rewritten by the LAN masquerade could not be told from one rewritten by
a mapping's SNAT rule.

Phase 7 now checks only the port-forward rules, and the probes move to a
new Phase 8b, after Phase 8 has reclaimed the mapping. Phase 8b first
checks that the control socket reports no mapping to gw-server and that
the kernel's table holds no SNAT rule. If that gate fails, the probes are
recorded as failed rather than skipped silently, so a reclamation failure
cannot leave the forwards passing through the SNAT rule.

After the probes, Phase 8b reads the gateway's conntrack table and
checks, for each of the three forwards, that the reply goes to the
gateway's LAN address. A mapping's SNAT sends it to a pool address
instead, and no rewrite at all to gw-server's own mesh address, so each
case reds with the address it found.

The self-test's conntrack and proxy neighbour inputs are now taken
verbatim from real gateway suite runs: a healthy run's table after the
inbound probes, a mapping's SNAT entry, and a wrong-interface run's
unreplied entries and neighbour entries. Inputs that need two situations
at once join lines from different runs.
2026-09-26 18:59:43 +00:00
..
2026-08-30 10:42:59 +00:00

Static Docker Network Test Harness

Multi-node integration test for FIPS using Docker containers with fixed topologies. Multiple topologies are provided: a sparse mesh (5 nodes, 6 links), a linear chain (5 nodes, 4 links), a gateway topology (3 nodes plus a non-FIPS LAN client), and three rekey variants. All exercise the full FIPS stack including TUN devices, DNS resolution, peer link encryption, spanning tree construction, and discovery-driven multi-hop routing.

Prerequisites

  • Docker with the compose plugin
  • Rust toolchain (for building the FIPS binary)
  • Python 3 (for identity derivation; stdlib only, no packages required)

Quick Start

Build the binaries and images, then generate the node configs:

./testing/scripts/build.sh
./testing/static/scripts/generate-configs.sh mesh

build.sh is the shared harness builder and is run from the repo root; it does not generate configs.

Start the mesh (default topology):

docker compose -f testing/static/docker-compose.yml up -d
./testing/static/scripts/ping-test.sh mesh      # 20/20 expected
./testing/static/scripts/iperf-test.sh mesh     # bandwidth test
docker compose -f testing/static/docker-compose.yml down

The mesh profile is activated by default via .env. To use a different topology, specify the profile explicitly:

docker compose -f testing/static/docker-compose.yml --profile chain up -d
./testing/static/scripts/ping-test.sh chain
docker compose -f testing/static/docker-compose.yml --profile chain down

Topologies

Mesh

Mesh Topology

Five nodes with 6 bidirectional UDP links forming a sparse, fully connected graph. Not all nodes are direct peers -- non-adjacent pairs require discovery-driven multi-hop routing to establish end-to-end sessions.

The spanning tree is rooted at node A, which has the lexicographically smallest NodeAddr (the first 16 bytes of SHA-256(pubkey)). Tree edges are highlighted in blue in the diagram above.

The ping test exercises all 20 directed pairs (5 nodes x 4 targets each), covering both direct-peer and multi-hop paths.

Link Type
A -- D tree edge (D's parent is A)
A -- E tree edge (E's parent is A)
C -- D tree edge (C's parent is D)
B -- C tree edge (B's parent is C)
D -- E non-tree link
C -- E non-tree link

Chain

Chain Topology

Five nodes in a linear chain: A -- B -- C -- D -- E. Each node peers only with its immediate neighbors. Multi-hop communication (e.g., A to E) requires the discovery protocol to find routes through intermediate nodes.

The ping test covers:

  • Adjacent hops: A->B, B->C (1 hop each)
  • Multi-hop: A->C (2 hops), A->D (3 hops), A->E (4 hops)
  • Reverse: E->A (4 hops)

Gateway

Three FIPS nodes: a gateway (a) with a LAN interface, and two mesh destinations (b, c) directly peered with it. A non-FIPS client container attaches to the gateway's LAN interface. Two destinations are required so the multi-client phase of gateway-test.sh can allocate distinct virtual-IP mappings, one per LAN client. Identities are derived deterministically from the mesh name gateway-test.

Rekey

Same sparse mesh as the mesh topology (5 nodes, 6 links). Configs are post-processed to use aggressive rekey timers (35s) for CI testing. The rekey-test.sh script handles config injection and multi-phase verification.

Rekey-Accept-Off

The rekey topology with transports.udp.accept_connections: false set on node B, the single-peer node auto-connected to C. Pins the regression where a rekey msg1 arriving at an auto-connect initiator with accept off was dropped by the Node-level admission gate.

Rekey-Outbound-Only

The rekey topology with transports.udp.outbound_only: true on node B, whose peer-C address is also rewritten to the Docker hostname (node-c:2121). Pins the regression where the hostname-versus-numeric mismatch made the addr_to_link lookup miss and the admission carve-out fall through.

Configuration Management

File Structure

testing/static/
├── docker-compose.yml                  # Service definitions for all topologies
├── docker-compose.gateway-external-net.yml  # Gateway on an external network
├── .env                                # Default compose profile
├── configs/
│   ├── node.template.yaml              # Template for all node configs
│   ├── gateway-resolv.conf             # LAN client resolver config
│   └── topologies/
│       ├── mesh.yaml                   # Mesh topology definition
│       ├── chain.yaml                  # Chain topology definition
│       ├── gateway.yaml                # Gateway integration test (3 nodes)
│       ├── rekey.yaml                  # Rekey integration test (5 nodes)
│       ├── rekey-accept-off.yaml       # Rekey with accept_connections off
│       └── rekey-outbound-only.yaml    # Rekey with outbound_only
├── generated-configs/                  # Auto-generated, run-scoped (gitignored)
│   ├── npubs.env                       # NPUB_A=..., NPUB_B=..., etc.
│   ├── mesh/
│   │   ├── node-a.yaml ... node-e.yaml
│   └── chain/
│       ├── node-a.yaml ... node-e.yaml
├── scripts/
│   ├── generate-configs.sh             # Generate node configs from topology
│   ├── ping-test.sh                    # Connectivity test
│   ├── iperf-test.sh                   # Bandwidth test
│   ├── iperf-compare-refs.sh           # Bandwidth comparison across refs
│   ├── bench-multirun.sh               # Repeated benchmark runs
│   ├── gateway-test.sh                 # Gateway integration test
│   ├── rekey-test.sh                   # Rekey integration test
│   ├── admission-cap-test.sh           # Peer admission cap test
│   └── netem.sh                        # Network impairment
├── docker-mesh-topology.svg            # Mesh topology diagram
└── docker-chain-topology.svg           # Chain topology diagram

The container image definition (Dockerfile), its entrypoint and the resolv.conf that points at the FIPS resolver are shared with the other harnesses and live in testing/docker/. The identity-derivation helper is testing/lib/derive_keys.py.

Topology Files

Each topology file in configs/topologies/ defines:

  • Node identities: nsec (hex) and npub (bech32) for each node
  • Addresses: docker_ip for Docker-managed nodes, external_ip for remote nodes not managed by Docker
  • Peer connections: which nodes peer with each other
  • docker_host (optional): the compose hostname: this node answers to, when that is not node-<id>. Only the gateway topology needs it

Generated peer addresses use the docker hostname, not docker_ip. fips-net requests no subnet, so docker assigns one from its own pool and two concurrent CI runs can bring the topology up at the same time instead of one of them failing with Pool overlaps. docker_ip is retained as documentation of the topology's shape and as the internal/external discriminator; an external node keeps its external_ip in peer blocks, its address not being ours to assign.

Example entry:

nodes:
  a:
    nsec: "0102030405060708..."
    npub: "npub1sjlh2c3..."
    docker_ip: "172.20.0.10"
    peers: [d, e]

External nodes use external_ip instead of docker_ip. Config generation skips external nodes (they run outside Docker) but includes their identity in peer blocks and the npubs environment file.

Generating Configs

./testing/static/scripts/generate-configs.sh <topology> [mesh-name]

This reads the topology definition and generates:

  1. Per-node YAML config files in generated-configs/<topology>/
  2. generated-configs/npubs.env with all node npubs as environment variables

Under ci-local.sh the directory is generated-configs-<run-id>, so concurrent runs cannot overwrite each other's node configs; the compose file and every test script read the same FIPS_CI_NAME_SUFFIX and follow it. A bare invocation leaves the suffix unset and writes the plain path.

The npubs.env file is sourced by the test scripts and injected into Docker containers via env_file in docker-compose.yml.

testing/scripts/build.sh compiles the binaries and builds the images; run generate-configs.sh separately afterwards.

Adding a New Topology

  1. Create configs/topologies/<name>.yaml following the format of mesh.yaml
  2. Add corresponding service definitions to docker-compose.yml with profiles: ["<name>"]
  3. Run ./testing/static/scripts/generate-configs.sh <name> to generate configs

Deterministic Mesh Identity Derivation

When running multiple test meshes that may peer with the same external node, each mesh needs unique node identities to avoid key conflicts. The optional mesh-name parameter generates deterministic per-mesh identities:

./testing/static/scripts/generate-configs.sh mesh my-mesh-1
./testing/static/scripts/generate-configs.sh chain my-mesh-1

How It Works

For each Docker node (those with docker_ip), the identity is derived as:

nsec = sha256(mesh_name + "|" + node_id)    # e.g., sha256("my-mesh-1|a")
npub = bech32("npub", secp256k1_pubkey(nsec))

External nodes (those with external_ip) always keep their hardcoded identity from the topology YAML, since they represent real nodes outside the test environment.

Without a mesh name, the identities from the topology YAML are used as-is (the original behavior).

The derive_keys.py Script

The derivation is performed by testing/lib/derive_keys.py, a standalone tool with no external dependencies (pure Python stdlib: hashlib for SHA-256, manual secp256k1 scalar multiplication, and BIP-173 bech32 encoding):

$ python3 testing/lib/derive_keys.py my-mesh-1 a
nsec=<64-char-hex>
npub=npub1...

The npubs.env File

Every run of generate-configs.sh writes generated-configs/npubs.env containing all node npubs, whether derived or from the topology YAML:

NPUB_A=npub1...
NPUB_B=npub1...
NPUB_C=npub1...
NPUB_D=npub1...
NPUB_E=npub1...

This file is:

  • Sourced by test scripts (ping-test.sh, iperf-test.sh) to resolve node identities for DNS lookups
  • Injected into containers via the env_file directive in docker-compose.yml, making $NPUB_A etc. available as environment variables inside each container

Performance Testing

./testing/static/scripts/iperf-test.sh [mesh|chain]
./testing/static/scripts/iperf-test.sh mesh --live   # show live iperf3 output

Runs iperf3 with:

  • Duration: 10 seconds (-t 10)
  • Parallel streams: 8 (-P 8)
  • Protocol: TCP over IPv6

For before/after measurements across commits or branches:

./testing/static/scripts/iperf-compare-refs.sh origin/master HEAD mesh

The comparison script builds each ref into a separate Docker image, runs the same topology and iperf3 settings for both images, and prints a bandwidth summary. Override DURATION, PARALLEL, SETTLE_SECONDS, IPERF_TIMEOUT, or RUNS in the environment when needed. RUNS is the total number of measurements per ref; for example, RUNS=3 runs each ref three times and prints both per-run and aggregate tables.

Network Impairment

The netem.sh script simulates adverse network conditions using tc/netem on all running containers:

./testing/static/scripts/netem.sh [mesh|chain] <apply|remove|status> [options]

Options

Option Description
--delay <ms> Fixed delay in milliseconds
--jitter <ms> Delay variation (requires --delay)
--loss <percent> Packet loss percentage
--loss-corr <percent> Loss correlation for bursty loss
--duplicate <percent> Packet duplication percentage
--reorder <percent> Packet reordering probability (requires --delay)
--corrupt <percent> Bit-level corruption percentage

Presets

Preset Parameters
lossy 5% loss, 25% correlation
congested 50ms delay, 20ms jitter, 2% loss
terrible 100ms delay, 40ms jitter, 10% loss, 1% dup, 5% reorder

Examples

# Apply 50ms delay with 5% packet loss
./testing/static/scripts/netem.sh mesh apply --delay 50 --loss 5

# Use a preset
./testing/static/scripts/netem.sh chain apply --preset congested

# Check current rules
./testing/static/scripts/netem.sh mesh status

# Remove all impairment
./testing/static/scripts/netem.sh mesh remove

Rules are applied to egress on each container's eth0 interface. With all containers impaired equally, both directions of every link see the effect. The script uses tc qdisc replace so it can be re-run safely without removing rules first.

Container Configuration

  • Base image: debian:bookworm-slim
  • Capabilities: CAP_NET_ADMIN (for TUN device creation)
  • Devices: /dev/net/tun mapped into each container
  • DNS: FIPS built-in resolver on 127.0.0.1:53
  • Transport: UDP on port 2121 (MTU 1472) or TCP on port 8443
  • TUN: fips0 interface, MTU 1280

Each node resolves <npub>.fips DNS names to FIPS IPv6 addresses via its local DNS responder, which primes the identity cache for session establishment.

Background Services

Each container runs the following services alongside FIPS:

Service Port Description
SSH 22 Root login with no password (test only)
iperf3 5201 Bandwidth testing server (-s -D)
HTTP 80 Python HTTP server serving /root/index.html

All services bind to IPv6 (::) and are accessible over the FIPS overlay using <npub>.fips hostnames:

# HTTP over FIPS
docker exec fips-node-b curl http://$NPUB_A.fips

# SSH over FIPS
docker exec fips-node-b ssh $NPUB_A.fips

# iperf3 over FIPS
docker exec fips-node-b iperf3 -c $NPUB_A.fips

Troubleshooting

Stale images after code changes: Docker compose may cache old layers. Force a clean rebuild:

docker compose -f testing/static/docker-compose.yml build --no-cache

Check node logs:

docker logs fips-node-a
docker logs -f fips-node-c    # follow

Verify DNS resolution inside a container:

docker exec fips-node-a dig AAAA <npub>.fips @127.0.0.1

Verify binary is up to date: Compare hashes between the local build and the binary inside the container:

md5sum testing/docker/fips
docker exec fips-node-a md5sum /usr/local/bin/fips

Increase convergence time: If tests fail intermittently, the 5-second convergence wait in ping-test.sh may be insufficient. Edit the sleep value at the top of the script.

Missing npubs.env: If test scripts fail with "npubs.env not found", run ./testing/static/scripts/generate-configs.sh mesh (or your topology) first.