Johnathan Corgan
7df1f21429
Design documentation refresh: MMP, wire formats, and configuration alignment
...
Bring all 9 design documents into alignment with the current
implementation. Major additions include MMP coverage at both link and
session layers, wire format tables for SenderReport and ReceiverReport,
UDP socket buffer sizing, PathMtuNotification status updates, and
configuration parameter fixes (default_ttl key name, idle timeout MMP
exclusion semantics).
2026-02-19 06:45:46 +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
d46dc874ef
Restructure design docs around protocol layers
...
Reorganize FIPS design documentation from implementation-centric
structure (routing, gossip protocol, wire protocol, transports) to
protocol-layer organization with clear service boundaries.
New documents (8):
- fips-transport-layer.md — transport layer spec
- fips-link-layer.md — FLP spec (peer auth, link encryption, forwarding)
- fips-session-layer.md — FSP spec (end-to-end encryption, sessions)
- fips-ipv6-adapter.md — IPv6 adaptation (TUN, DNS, MTU enforcement)
- fips-mesh-operation.md — routing, discovery, error recovery
- fips-wire-formats.md — consolidated wire format reference
- fips-spanning-tree.md — tree algorithm reference
- fips-bloom-filters.md — bloom filter math reference
Rewritten (2):
- fips-intro.md — breadth-first intro with layer model diagrams
- fips-software-architecture.md — slimmed to stable decisions
Updated (3):
- spanning-tree-dynamics.md — removed stale root refresh, aligned terminology
- fips-configuration.md — fixed priority type (u16 → u8)
- fips-state-machines.md — synced code examples with codebase
Deleted (6): fips-transports.md, fips-wire-protocol.md,
fips-gossip-protocol.md, fips-session-protocol.md, fips-routing.md,
fips-tun-driver.md (content absorbed into new structure)
2026-02-17 04:50:04 +00:00
Johnathan Corgan