fips/examples/docker-network

Docker Network Test Harness

Multi-node integration test for FIPS using Docker containers. Two topologies are provided: a sparse mesh (5 nodes, 6 links) and a linear chain (5 nodes, 4 links). Both 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)

Quick Start

Build the binary and copy it to the docker context:

./scripts/build.sh

Mesh Topology

docker compose --profile mesh build
docker compose --profile mesh up -d
./scripts/ping-test.sh mesh      # 20/20 expected
docker compose --profile mesh down

Chain Topology

docker compose --profile chain build
docker compose --profile chain up -d
./scripts/ping-test.sh chain     # 6/6 expected
docker compose --profile chain down

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 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)

Node Identities

All nodes use deterministic test keys (not for production use).

Node	npub	FIPS IPv6 Address	Docker IP
A	npub1sjlh2c3...	fd69:e08d:65cc:3a6b:...	172.20.0.10
B	npub1tdwa4vj...	fd8e:302c:287e:b48d:...	172.20.0.11
C	npub1cld9yay...	fdac:a221:4069:5044:...	172.20.0.12
D	npub1n9lpnv0...	fdb6:8411:a191:6d48:...	172.20.0.13
E	npub1wf8akf8...	fded:7dee:d386:a546:...	172.20.0.14

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 4000, MTU 1280
• 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.

Troubleshooting

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

docker compose --profile mesh 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 npub1tdwa4vjrjl33pcjdpf2t4p027nl86xrx24g4d3avg4vwvayr3g8qhd84le.fips @127.0.0.1

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

md5sum examples/docker-network/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.