Files
fips/testing/static
Martti MalmiandJohnathan Corgan 0a5c367edc data-plane perf overhaul: off-task encrypt + decrypt, GSO, connected UDP
Moves both AEAD layers (ChaCha20-Poly1305, one round per layer per
packet) plus the sendmsg syscall off the rx_loop task onto a per-shard
worker pool, adds per-peer connect(2)-ed UDP with SO_REUSEPORT, and
uses Linux UDP GSO (sendmsg+UDP_SEGMENT — kernel splits one super-skb
into N on-the-wire datagrams in a single TX-stack walk) when packets
in a batch are uniform-size. Same kernel primitive WireGuard's
in-kernel module and BoringTun use to hit 2.5–3.2 Gbps single-stream.

Single TCP stream on a 5-node docker-bridge mesh, 5 x 15 s x P=1:

  A→D:  1379 → 2708 Mbps  (1.96x, RTT +0.12 ms)
  A→E:  1394 → 2663 Mbps  (1.91x, RTT +0.11 ms)
  E→A:  1406 → 2624 Mbps  (1.87x, RTT +0.19 ms)

Static-peer pairs only — every CoV under 3%, 0 outliers, 0% ICMP
loss. The ~+100 µs RTT is the worker queue handoff cost; AEAD +
sendmmsg now run on a separate core in exchange.

What lands:

- src/node/encrypt_worker.rs: std::thread + crossbeam_channel
  workers; hash-by-destination dispatch pins a TCP flow to one
  worker so wire ordering is preserved; per-worker sendmmsg(2)
  batching up to 32; Linux uses sendmsg(2)+UDP_SEGMENT when
  packets in a group are uniform-size.

- src/node/decrypt_worker.rs: receive-side mirror. Each shard owns
  its session's recv cipher + replay window in a thread-local
  HashMap (no shared RwLock/Mutex). Sessions are handed off at
  promote_connection and re-registered on K-bit flip / rekey
  cutover.

- src/node/handlers/session.rs try_send_session_data_pipelined:
  FSP+FMP both seal in-place in the worker on one wire-buffer
  alloc; no intermediate inner_plaintext / fsp_payload Vecs.

- src/transport/udp/connected_peer.rs + peer_drain.rs: per-peer
  connect(2)-ed UDP socket with SO_REUSEPORT (set on the listen
  socket too — without that, EADDRINUSE on activation and every
  packet falls back to the wildcard path); the worker sends with
  msg_name=NULL and the kernel uses its cached 5-tuple. Tick-
  driven activation in handlers/connected_udp.rs, idempotent.

- src/transport/udp/mod.rs: mem::replace the recvmmsg backing buffer
  instead of buf.to_vec() per packet — single pointer swap, no
  MTU-sized memcpy.

- src/protocol/link.rs SessionDatagramRef: zero-copy borrowed view
  used by handle_session_datagram for the bulk local-delivery
  path; handle_session_payload takes the borrowed payload
  directly (no payload[35..].to_vec()).

- src/transport/mod.rs TransportAddr::from_socket_addr: collapses
  the two-alloc from_string(addr.to_string()) pattern to one.

- src/node/handlers/rx_loop.rs: decrypt-fallback drain promoted
  ahead of packet_rx in the select! (TCP ACK starvation fix);
  interleaved fallback drain every 32 packets inside the rx burst
  loop.

- noise::Session: send_cipher_clone / recv_cipher_clone /
  recv_replay_snapshot_owned / take_send_counter / accept_replay
  so off-task workers can hold a cloned cipher + reserved counter
  while the dispatcher keeps replay/counter sequencing serial.
  CipherState::cipher_clone returns a refcount-bumped LessSafeKey.
  AsyncUdpSocket: AsRawFd so workers issue raw sendmmsg / sendmsg
  without going through the tokio reactor.

- Worker pool sizing: both default to num_cpus, overridable via
  FIPS_ENCRYPT_WORKERS=N / FIPS_DECRYPT_WORKERS=N. Per-peer
  connected UDP can be disabled via FIPS_CONNECTED_UDP=0.

- src/perf_profile.rs: optional per-stage timing reporter under
  FIPS_PERF=1 (or FIPS_PIPELINE_TRACE=1). Off by default; zero
  overhead when disabled.

- All cfg(unix)-gated. Windows continues on the existing tokio-
  based send/recv.

Decrypt worker session lifecycle:

- Node::unregister_decrypt_worker_session mirrors the existing
  register helper. Wired at the two natural sites that already
  iterate peers_by_index: the rekey drain-completion block in
  handlers/rekey.rs (drops the worker entry for the old our_index
  once the drain window has expired and the cache_key is
  unreachable to any in-flight OLD-K packet), and remove_active_peer
  in handlers/dispatch.rs (drops the worker entry for each of the
  four index slots: current, rekey, pending, previous). Only
  our_index is normally registered; unregister_session is fire-
  and-forget for missing entries, so calling unconditionally on
  all four slots is correct and bounds the cleanup without per-
  slot accounting. Without these callers the per-worker sessions
  HashMap and the Node's decrypt_registered_sessions set would
  grow monotonically per rekey on long-lived peers.

Testing:

- testing/static/scripts/bench-multirun.sh: multi-run iperf3 +
  ping bench. N reruns (default 5), median / min / max / CoV % /
  per-run outlier flag, avg ping RTT, ICMP loss %, TCP retransmit
  total. Plain client→dest labels + topology header. Pre-bench
  peer-convergence check (FIPS_BENCH_CONVERGE_SECS, default 15);
  per-path route verification via stats.bytes_sent deltas — fails
  fast if traffic exits via a non-static-peer link.

- testing/static/docker-compose.yml: passes FIPS_ENCRYPT_WORKERS /
  FIPS_DECRYPT_WORKERS / FIPS_PERF through to containers for A/B
  benchmarking without rebuilds.

- testing/static/scripts/iperf-test.sh: same plain client→dest
  labels + topology header (was multihop/direct/N hop, which
  conflated topology distance with on-wire path).

- .config/nextest.toml: synthetic UDP node tests serialized
  through a max-threads=1 test group. Localhost handshakes drop
  on shared CI runners under parallel load; one-at-a-time keeps
  assertions reliable.

- src/node/tests/spanning_tree.rs: repair_missing_edge_handshakes
  — retries up to 5 times for synthetic edges whose msg1 was
  dropped, with a drain after each edge retry instead of after
  each attempt's full burst.

- src/node/decrypt_worker.rs::tests: two unit tests asserting
  WorkerMsg::UnregisterSession removes the worker-thread session
  HashMap entry (handle_msg_unregister_session_removes_entry) and
  is a no-op for never-seen cache_keys
  (handle_msg_unregister_session_idempotent_on_unknown_key), which
  is the safety invariant the unconditional unregister calls at
  the four index slots in remove_active_peer rely on.

- src/node/encrypt_worker.rs::unix_tests
  pipelined_send_wire_layout_roundtrips_canonical_decoders: mirrors
  the encoder geometry of try_send_session_data_pipelined (no
  coords, the common established-session path), runs the worker's
  real seal + send via flush_direct_batch_sync, and decodes the
  resulting wire packet using only canonical receive-side decoders
  (EncryptedHeader::parse, SessionDatagramRef::decode, FSP header
  parse, noise::open). Any divergence between the hand-rolled
  encoder offsets (fsp_aad_offset, fsp_plaintext_offset) and the
  decoders fails at one of the parse / open / decode steps before
  the inner-plaintext assertion fires. Complements the existing
  fsp_preseal_runs_before_outer_fmp_seal test which covers the
  seal-ordering invariant with synthetic headers but does not
  exercise the wire-layout invariant.

CHANGELOG.md [Unreleased] # Changed entry added describing the
worker-pool threading model, hash-by-destination dispatch,
sendmmsg/UDP_GSO, per-peer connected UDP, the operator-facing env
vars, and the bench numbers above.

Cherry-picks from mmalmi/master (paths translated from
crates/fips-core/src/ to src/): 9b7c723, 0deb5cb, 13f7339, e036c0e,
3740a68, 3792f83, 8510193, 4910b07, e53f545, e4e2896, 5fe4af5,
1d01ada, 8c37008, e12469e, 6eb2860.

Co-authored-by: Johnathan Corgan <johnathan@corganlabs.com>
2026-05-19 20:53:31 +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 mesh with a public external node, and a TCP chain (3 nodes). 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 binary and generate configs:

./testing/static/scripts/build.sh

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)

Mesh-Public

Same five Docker nodes as the mesh topology, plus an external public node (pub) at a remote IP. Nodes A, B, and C peer with the public node. This topology is for testing mixed local/remote mesh operation.

External nodes are not managed by Docker -- only their identity and address appear in the topology file so that Docker nodes can peer with them.

TCP Chain

Three nodes in a linear chain using TCP transport (port 8443) instead of UDP: A -- B -- C. Each node peers only with its immediate neighbors. Tests basic TCP transport connectivity and multi-hop routing over TCP.

The topology file sets default_transport: tcp, which causes config generation to use TCP peer addresses (port 8443), inject the TCP transport section, and remove the UDP transport section.

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.

Configuration Management

File Structure

testing/static/
├── Dockerfile                          # Container image definition
├── docker-compose.yml                  # Service definitions for all topologies
├── resolv.conf                         # DNS config pointing to FIPS resolver
├── .env                                # Default compose profile
├── configs/
│   ├── node.template.yaml              # Template for all node configs
│   └── topologies/
│       ├── mesh.yaml                   # Mesh topology definition
│       ├── chain.yaml                  # Chain topology definition
│       ├── mesh-public.yaml            # Mesh + external public node
│       ├── tcp-chain.yaml             # TCP chain (3 nodes, port 8443)
│       └── rekey.yaml                 # Rekey integration test (5 nodes)
├── generated-configs/                  # Auto-generated (gitignored)
│   ├── npubs.env                       # NPUB_A=..., NPUB_B=..., etc.
│   ├── mesh/
│   │   ├── node-a.yaml ... node-e.yaml
│   ├── mesh-public/
│   │   ├── node-a.yaml ... node-e.yaml
│   ├── chain/
│   │   ├── node-a.yaml ... node-e.yaml
│   └── tcp-chain/
│       ├── node-a.yaml ... node-c.yaml
├── scripts/
│   ├── build.sh                        # Build binary + generate configs
│   ├── generate-configs.sh             # Generate node configs from topology
│   ├── derive-keys.py                  # Deterministic nsec/npub derivation
│   ├── ping-test.sh                    # Connectivity test
│   ├── iperf-test.sh                   # Bandwidth test
│   └── netem.sh                        # Network impairment
├── docker-mesh-topology.svg            # Mesh topology diagram
└── docker-chain-topology.svg           # Chain topology diagram

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

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

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

The build script (scripts/build.sh) calls generate-configs.sh automatically after compiling.

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:

# Build with derived identities
./testing/static/scripts/build.sh mesh my-mesh-1

# Or generate configs directly
./testing/static/scripts/generate-configs.sh mesh my-mesh-1
./testing/static/scripts/generate-configs.sh mesh-public 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 scripts/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):

$ ./testing/static/scripts/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...
NPUB_PUB=npub1...    # only present for topologies with a pub node

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/static/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, or use ./testing/static/scripts/build.sh which generates configs automatically.