Commit Graph
7 Commits
Author SHA1 Message Date
Johnathan Corgan 04d9fd625d FSP wire format revision and session-layer MMP implementation
FSP wire format revision (TASK-2026-0007):

Introduce the FIPS Session Protocol (FSP) wire format with a 4-byte
common prefix [ver_phase:1][flags:1][payload_len:2 LE] replacing the
old 1-byte msg_type dispatch. All session messages share this prefix
with phase-based dispatch (Established, Setup, Ack, Unencrypted).

- New session_wire.rs: FSP constants, header types, parse/build helpers
- SessionMessageType enum: DataPacket (0x10), SenderReport (0x11),
  ReceiverReport (0x12), PathMtuNotification (0x13)
- FspFlags (CP/K/U) and FspInnerFlags (SP) for flag management
- SessionSenderReport, SessionReceiverReport, PathMtuNotification
  message structs with encode/decode
- FSP send pipeline: 12-byte header as AAD, 6-byte inner header
  (timestamp + msg_type + inner_flags), encrypt_with_aad()
- FSP receive pipeline: parse header, extract cleartext coords (CP),
  AEAD decrypt with AAD, strip inner header, msg_type dispatch
- Forwarding: transit nodes parse cleartext coords without decryption
- Removed DataPacket struct and associated types
- SessionEntry: session_start_ms, mark_established(), session_timestamp()
- FIPS_OVERHEAD: 144 → 150 bytes (+6 for FSP inner header)
- Design docs updated for new wire format

Session-layer MMP implementation (TASK-2026-0008):

Implement complete session-layer MMP reusing the link-layer algorithm
modules (SenderState, ReceiverState, MmpMetrics, SpinBitState) with
independent configuration and higher report interval clamps.

- SessionMmpConfig: separate config section (node.session_mmp.*)
- MmpSessionState: session-specific wrapper with PathMtuState tracking
- Session-layer constants (500ms-10s report intervals, 1s cold start)
- Parameterized interval methods (new_with_cold_start,
  update_report_interval_with_bounds) on SenderState/ReceiverState
- Bidirectional From conversions between link/session report types
- SessionEntry: mmp and is_initiator fields, initialized on Established
- send_session_msg() for reports/notifications
- Per-message RX recording with spin bit state tracking
- Handlers for SenderReport, ReceiverReport, PathMtuNotification
- path_mtu threaded from SessionDatagram envelope through to handlers
- check_session_mmp_reports() tick handler with collect-then-send pattern
- Periodic and teardown operator logging for session metrics
- PathMtuState: destination observes incoming MTU on all session messages,
  source seeded from outbound transport MTU, decrease-immediate /
  increase-requires-3-consecutive rules

Link-layer MMP fix:

- Stop feeding spin bit RTT samples into SRTT estimator; inter-frame
  timing in the mesh is irregular, inflating spin-bit RTT by variable
  processing delays; timestamp-echo provides accurate RTT

29 files changed, 602 tests pass, 0 clippy warnings.
2026-02-19 03:15:05 +00:00
Johnathan Corgan d8cb4d407e FLP wire format revision and MMP link-layer measurement protocol
## FLP Wire Format Revision

Replace the 1-byte discriminator with a structured wire format:

- 4-byte common prefix (ver+phase, flags, payload_len) and 16-byte
  established frame header with AEAD AAD binding
- 5-byte encrypted inner header (4-byte session-relative timestamp +
  1-byte message type) on all link messages
- Phase-based packet dispatch replacing discriminator-based dispatch
- SessionDatagram reassigned from type 0x40 to 0x00; add SenderReport
  (0x01) and ReceiverReport (0x02) message types for MMP
- SessionDatagram: rename hop_limit to ttl, add path_mtu field (u16 LE)
  with min(datagram.path_mtu, transport.mtu()) at forwarding
- Updated handshake packets (msg1: 87->90 bytes, msg2: 42->45 bytes)
- FIPS_OVERHEAD updated from 135 to 144 bytes

## MMP Link-Layer Measurement Protocol

Add the Metrics Measurement Protocol for link quality measurement
between FIPS peers. Measures RTT, loss, jitter, throughput, OWD trend,
and ETX from periodic sender/receiver reports exchanged over established
links.

Module layout:
- mmp/algorithms.rs: JitterEstimator, SrttEstimator, DualEwma, OwdTrend,
  SpinBit, ETX computation
- mmp/report.rs: SenderReport (48B) and ReceiverReport (68B) wire format
- mmp/sender.rs: per-peer TX counters and interval tracking
- mmp/receiver.rs: per-peer RX counters, jitter, loss, gap tracking
- mmp/metrics.rs: derived metrics from report processing (SRTT, goodput_bps)
- mmp/mod.rs: MmpMode (Full/Lightweight/Minimal), MmpConfig, MmpPeerState
- node/handlers/mmp.rs: report dispatch, timer-driven generation, operator
  logging (periodic + teardown)

Integration: per-frame TX/RX hooks in encrypted message handling, report
dispatch from link message router, timer-driven generation from tick
handler, and periodic operator logging with throughput formatting.

Three operating modes: Full (sender + receiver reports, spin bit, CE echo),
Lightweight (receiver reports only), Minimal (spin bit + CE echo only).

## Design Documentation

Updated FLP sections across all design documents to match the implemented
wire format, including revised overhead calculations and numeric values.

568 tests pass, clippy clean.
2026-02-18 21:54:21 +00:00
Johnathan Corgan 3ca2f9500a Error recovery fixes and routing error rate limiting
- PathBroken handler: convert to async, trigger re-discovery via
  maybe_initiate_lookup(), reset COORDS_PRESENT warmup counter
  (was a stub that only invalidated coord_cache)

- CoordsRequired recovery timing: reset warmup counter in
  handle_lookup_response() when discovery completes for an
  established session, so COORDS_PRESENT packets fire after
  fresh coords are available (not just on CoordsRequired receipt)

- Routing error rate limiting: add RoutingErrorRateLimiter
  (100ms per-destination, matching ICMP PTB pattern) to gate
  send_routing_error() at transit nodes

- Remove root refresh dead code: the 1800s periodic root
  re-announcement in check_tree_state() only propagated to
  depth 1 (sequence-only changes don't cascade). Root loss
  detection relies on link failure propagation which works
  correctly.
2026-02-17 00:00:04 +00:00
Johnathan Corgan 1f60fbd7a2 COORDS_PRESENT warmup-then-reactive for DataPackets
Include source and destination coordinates on the first N DataPackets
of each session (default 5, configurable via
node.session.coords_warmup_packets). This warms transit node
coord_caches so multi-hop forwarding and error signal routing work
after SessionSetup cache entries expire.

On CoordsRequired receipt, reset the counter to re-enable coordinate
inclusion for the next N packets, handling mid-session cache expiry
and path changes.

Changes:
- SessionConfig: add coords_warmup_packets field (default 5)
- SessionEntry: add coords_warmup_remaining counter, initialized on
  Established transition (both initiator and responder paths)
- send_session_data(): attach coords via DataPacket::with_coords()
  while counter > 0, decrement per send
- handle_coords_required(): reset counter for affected session
- 4 new unit tests for counter lifecycle and config default
2026-02-16 23:28:24 +00:00
Johnathan Corgan f374370e5c Cache architecture: identity fix, cache merge, parent-change flush
Identity cache: remove TTL-based expiry (60s TTL broke active sessions
after expiry since handle_tun_outbound checks identity_cache before
session table). Replace with LRU-only eviction bounded by configurable
identity_size (default 10K). Lookup now touches timestamp for LRU
freshness.

Cache merge: unify coord_cache and route_cache into single coordinate
cache. Both stored NodeAddr→TreeCoordinate; the layer distinction was
conceptual, not functional. Discovery-sourced entries now get the same
TTL+refresh treatment as session-sourced entries. Simplifies
find_next_hop() to single cache lookup.

Parent-change flush: clear coord_cache after recompute_coords() in both
parent-switch paths of handle_tree_announce(). Stale coordinates after
tree reconvergence cause dead-end routing that's more expensive than
re-discovery.

Tested: 493 unit tests passed, clippy clean, Docker mesh 20/20,
Docker chain 6/6.
2026-02-16 22:56:34 +00:00
Johnathan Corgan 5f1c6c2c7c Add session idle timeout (90s) and identity cache expiry (60s)
Sessions in the Established state that have no activity for 90 seconds
are now automatically removed. This ensures idle sessions are torn down
before transit node coord_cache entries expire (300s TTL), so that when
traffic resumes a fresh SessionSetup re-warms transit node caches with
current coordinates.

The identity cache now stores registration timestamps and expires
entries after 60 seconds via lazy expiry on lookup. This prevents
unbounded growth while allowing natural repopulation through DNS
resolution on next use.

Timer ordering: identity (60s) < session (90s) < coord_cache (300s).

Both timeouts are configurable: node.session.idle_timeout_secs and
node.cache.identity_ttl_secs. Setting idle_timeout_secs to 0 disables
session idle purging.

Changes:
- Add idle_timeout_secs (default 90) to SessionConfig
- Add identity_ttl_secs (default 60) to CacheConfig
- Add timestamp to identity_cache entries, lazy expiry on lookup
- Add purge_idle_sessions() called from tick loop
- Remove #[cfg(test)] from SessionEntry::last_activity()
- 7 new tests covering timeout behavior and edge cases
2026-02-16 13:13:05 +00:00
Johnathan Corgan 930f139787 Split cache.rs and config.rs into directory modules, create utils/
Module reorganization for three large single-file modules:

cache.rs (792 lines) split into cache/ directory:
- cache/mod.rs: CacheError, CacheStats, re-exports
- cache/entry.rs: CacheEntry with TTL/LRU tracking
- cache/coord_cache.rs: CoordCache (address-to-coordinate mappings)
- cache/route_cache.rs: RouteCache + CachedCoords (discovery routes)
- Added 22 new tests filling coverage gaps across all submodules

config.rs (1318 lines) split into config/ directory:
- config/mod.rs: ConfigError, IdentityConfig, Config struct with file
  loading/merge logic, all 24 integration tests
- config/node.rs: NodeConfig + 9 subsection structs (Limits, RateLimit,
  Retry, Cache, Discovery, Tree, Bloom, Session, Buffers)
- config/transport.rs: TransportInstances<T>, TransportsConfig, UdpConfig
- config/peer.rs: ConnectPolicy, PeerAddress, PeerConfig

DnsConfig and TunConfig moved to upper/config.rs to co-locate with the
upper layer components they configure (TUN interface, DNS responder).

index.rs moved to utils/index.rs as cross-cutting infrastructure that
serves both node and peer layers.
2026-02-15 17:56:32 +00:00