Files
fips/testing
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
..

FIPS Testing

Integration and simulation test harnesses for FIPS, using Docker containers running the full protocol stack.

Test Harnesses

static/ -- Static Docker Network

Fixed topologies with manual scripts for building, config generation, connectivity tests (ping, iperf), and network impairment (netem). Useful for deterministic debugging and validating specific topology configurations.

Topology Nodes Transport Description
mesh 5 UDP Sparse mesh, 6 links, multi-hop
chain 5 UDP Linear chain, max 4-hop paths
mesh-public 5+1 UDP Mesh with external public node
tcp-chain 3 TCP Linear chain over TCP (port 8443)
rekey 5 UDP Rekey integration test topology

tor/ -- Tor Transport Integration

End-to-end Tor transport testing with Docker containers running real Tor daemons. Requires internet access for Tor bootstrapping.

Scenario Description
socks5-outbound Outbound SOCKS5 connections through Tor to clearnet peer
directory-mode Inbound via HiddenServiceDir onion service (co-located)

nat/ -- NAT Traversal Lab

Real Docker NAT traversal tests for the Nostr/STUN bootstrap path, using router containers with iptables-based NAT, a local Nostr relay, and a local STUN responder.

Scenario Description
cone Two NATed peers establish a UDP traversal path
symmetric UDP traversal fails under symmetric NAT, TCP fallback wins
lan Peers on the same LAN prefer local addresses over reflexive

chaos/ -- Stochastic Simulation

Automated network testing with configurable node counts, topology algorithms (random geometric, Erdos-Renyi, chain, explicit), and fault injection (netem mutation, link flaps, traffic generation, node churn). 20 scenarios covering general stress testing, cost-based parent selection, mixed link technologies (fiber/Bluetooth/WiFi), transport-specific validation (UDP, TCP, Ethernet), and ECN/congestion testing. Scenarios are defined in YAML and executed via a Python harness that manages the full lifecycle: topology generation, Docker orchestration, fault scheduling, log collection, and analysis.