Gate platform-specific code behind cfg attributes and add full Windows
support: TUN device via wintun, TCP control socket on localhost:21210,
Windows Service lifecycle (--install-service/--uninstall-service/--service),
CI build and test matrix, and packaging with ZIP builder and PowerShell
service management scripts.
Key changes:
- Cargo.toml: move tun/libc/rtnetlink behind cfg(unix); add wintun and
windows-service dependencies for Windows
- upper/tun.rs: wintun-based TUN implementation with netsh configuration
for IPv6 address, MTU, and fd00::/8 routing
- control/mod.rs: split into unix_impl/windows_impl; Windows uses TCP on
localhost:21210 with shared connection handler
- bin/fips.rs: refactor main() into run_daemon() accepting a shutdown
signal; add Windows Service support via windows-service crate
- transport/udp/socket.rs: platform-gated modules; Windows uses
tokio::net::UdpSocket (kernel drop count unavailable, returns 0)
- transport/ethernet: gate to cfg(unix); add Windows stub types
- config: platform-conditional default paths (socket, hosts) for Windows
- CI: add windows-latest to build matrix and test-windows job with
cargo-nextest
- packaging/windows: build-zip.ps1, install-service.ps1,
uninstall-service.ps1, and package-windows.yml workflow
- README/docs: Windows build instructions, service management, and
control socket platform differences
Linux and macOS behavior is unchanged.
Add fips-gateway binary: a separate daemon that allows unmodified LAN
hosts to reach FIPS mesh destinations via DNS-allocated virtual IPs
and kernel nftables NAT.
Gateway DNS resolver: forwarding proxy on [::]:53 that intercepts
.fips queries, forwards to daemon resolver (localhost:5354), allocates
virtual IPs from pool, returns AAAA records. Always sends AAAA upstream
regardless of client query type, returns proper NODATA for non-AAAA.
Virtual IP pool: fd01::/112 pool with state machine lifecycle
(Allocated → Active → Draining → Free), TTL-based reclamation,
conntrack integration for session tracking.
NAT manager: nftables DNAT/SNAT rules via rustables netlink API,
per-mapping rule lifecycle, fips0 masquerade for LAN client source
address rewriting.
Network setup: local pool route, proxy NDP for virtual IPs on LAN
interface, IPv6 forwarding validation.
Control socket at /run/fips/gateway.sock with show_gateway and
show_mappings queries. fipstop Gateway tab with pool summary gauge
and mappings table.
Gateway config section in fips.yaml with pool CIDR, LAN interface,
DNS upstream, TTL, and grace period settings.
Design doc at docs/design/fips-gateway.md.
Integration test (testing/static/scripts/gateway-test.sh): three
containers verifying DNS resolution, end-to-end HTTP, NAT state,
TTL expiration, SERVFAIL fallback, and clean shutdown.
Replace burst beacon pattern (1s on / 30s off) with continuous
advertising. The burst pattern caused L2CAP connect timeouts because
the remote side was no longer connectable when the probe fired after
jitter delay. BLE advertising overhead is negligible (~0.15% duty
cycle on advertising channels).
Replace the seen HashSet + jitter delay queue with a simple cooldown
map. After probing an address (success or failure), suppress re-probe
for 30s (configurable via probe_cooldown_secs). Connected peers are
filtered by pool membership check. This eliminates the bug where
failed probes permanently blacklisted addresses for the session
lifetime.
Remove config fields: scan_interval_secs, beacon_interval_secs,
beacon_duration_secs. Add: probe_cooldown_secs.
BLE transport implementation using L2CAP Connection-Oriented Channels
(SeqPacket mode) via the bluer crate, behind cfg(feature = "ble").
Core transport:
- BleTransport<I> generic over BleIo trait (BluerIo prod, MockBleIo test)
- Connection pool with priority eviction (static > discovered, max 7)
- Connect-on-send via connect_inline() matching TCP behavior
- Per-connection receive loops with pool cleanup on disconnect
Discovery and probing:
- Combined scan_probe_loop using select! over scanner events and a
BinaryHeap delay queue with per-entry random jitter (0-5s) to prevent
herd effects when multiple nodes see the same beacon simultaneously
- Pre-handshake pubkey exchange ([0x00][pubkey:32]) for IK identity
- Cross-probe tie-breaker: smaller NodeAddr's outbound wins (same
convention as FMP/FSP rekey dual-initiation)
- Probed peers reported to DiscoveryBuffer; pool fills through normal
node-layer auto-connect -> send_async -> connect_inline path
Beacon management:
- Periodic advertising: 1s burst every 30s (configurable via
beacon_interval_secs / beacon_duration_secs)
- FIPS service UUID for scan filtering
Configuration (all fields optional with defaults):
- adapter, psm, mtu, max_connections, connect_timeout_ms
- advertise, scan, auto_connect, accept_connections
- beacon_interval_secs (30), beacon_duration_secs (1)
Hardware validated with two BLE nodes:
- 2048-byte MTU, ~60-160ms RTT, zero-config auto-connect
- BLE spike tool at testing/ble/ for standalone adapter validation
42 unit tests + 4 node-level integration tests, all CI-compatible
via MockBleIo (no hardware required). tokio test-util added for
time-dependent scan/probe tests.
The visited_bits field (hash_cnt + 256 bytes) was removed from the
LookupRequest wire format in the discovery-rework (bloom-guided tree
routing replaced the visited filter). Update the diagram to match the
current 46 + 16n byte format.
Bump version to 0.2.0 and finalize changelog with discovery rework,
Tor transport, connect/disconnect commands, reproducible builds, and
12 bug fixes.
Update design documentation for discovery protocol rework:
- fips-wire-formats.md: remove visited bloom filter from LookupRequest,
update size calculations
- fips-mesh-operation.md: replace flooding description with bloom-guided
tree routing, add retry/backoff/rate-limiting subsections
- fips-configuration.md: add 5 new discovery config parameters, update
control socket description for connect/disconnect commands
Add TorTransport in src/transport/tor/ supporting three operating modes:
Outbound (socks5 mode):
- Non-blocking SOCKS5 connect via tokio-socks with per-destination
circuit isolation (IsolateSOCKSAuth)
- TorAddr enum for .onion and clearnet address types
- Connection pool with per-connection receive tasks, reuses TCP
stream FMP framing
- connect_async()/connection_state_sync()/promote_connection() follow
the same non-blocking polling pattern as TCP transport
Inbound (directory mode — recommended for production):
- Tor manages the onion service via HiddenServiceDir in torrc
- FIPS reads .onion address from hostname file at startup
- No control port needed — enables Tor Sandbox 1 (seccomp-bpf)
- Accept loop mirrors TCP pattern with DirectoryServiceConfig
Monitoring (control_port mode and optional in directory mode):
- Async control port client supporting TCP and Unix socket connections
via Box<dyn AsyncRead/Write> trait objects
- AUTHENTICATE with cookie or password auth
- 8 GETINFO queries: bootstrap, circuits, traffic, liveness, version,
dormant state, SOCKS listeners
- Background monitoring task polls every 10s, caches TorMonitoringInfo
in Arc<RwLock> for synchronous query access
- Bootstrap milestone logging (25/50/75/100%), stall warning (>60s),
network liveness transitions, dormant mode entry
- Directory mode optionally connects to control port when control_addr
is configured (non-fatal on failure)
Operator visibility:
- show_transports query exposes tor_mode, onion_address, tor_monitoring
(bootstrap, circuit_established, traffic, liveness, version, dormant)
- fipstop transport detail view: Tor mode, onion address, SOCKS5/control
errors, connection stats, Tor daemon status section
- fipstop table view: tor(mode) label with truncated onion address hint
Security hardening:
- Per-destination circuit isolation via IsolateSOCKSAuth
- Unix socket default for control port (/run/tor/control)
- Reference torrc with HiddenServiceDir, VanguardsLiteEnabled,
ConnectionPadding, DoS protections (PoW + intro rate limiting)
Config:
- TorConfig with socks5, control_port, and directory modes
- DirectoryServiceConfig: hostname_file, bind_addr
- control_addr, control_auth, cookie_path, connect_timeout,
max_inbound_connections
Testing:
- 69 unit + integration tests with mock SOCKS5 and control servers
- Docker tests: socks5-outbound (clearnet via Tor) and directory-mode
(HiddenServiceDir onion service)
Documentation:
- Transport layer design doc: Tor architecture, directory mode
- Configuration doc: Tor config tables and examples
Add resolve_socket_addr() with IP fast path and tokio::net::lookup_host()
fallback for DNS hostnames. Peer addresses can now use hostnames like
"peer1.example.com:2121" alongside IP addresses.
UDP transport adds a per-transport DNS cache (60s TTL) to avoid
per-packet resolution. TCP resolves at connect time (one-shot).
Update design docs, config examples, and changelog to reflect hostname
support in transport addressing.
- Rewrite TCP "Connect-on-Send" section to document non-blocking connect
model (ConnectingPool, PendingConnect, poll_pending_connects)
- Add connect() and connection_state() to Transport trait surface
- Expand Connection Lifecycle section with ConnectionState enum
- Remove phantom TCP socks5_proxy field (removed from code, superseded
by TorConfig)
- Fix "future Tor transport" references (stream reader already shared)
- Replace misleading "tor:" named TCP instance example
- Update fips-intro.md implementation status (TCP and Ethernet are
implemented, not "under active design")
Breaking wire format change: DataPacket payloads inside the AEAD envelope
now carry a 4-byte port header [src_port:2 LE][dst_port:2 LE] before the
service payload. The receiver dispatches by destination port.
Port multiplexing:
- send_session_data() takes src_port/dst_port params, prepends port header
- New send_ipv6_packet() compresses IPv6 header and sends on port 256
- Receive path dispatches DataPackets by port: port 256 decompresses IPv6
header from session context and delivers to TUN, unknown ports dropped
- Port constants: FSP_PORT_HEADER_SIZE (4 bytes), FSP_PORT_IPV6_SHIM (256)
IPv6 header compression:
- New ipv6_shim module with compress_ipv6()/decompress_ipv6() pure functions
- Strips src/dst addresses (32 bytes) and payload length (2 bytes) from each
packet, preserving traffic class, flow label, next header, and hop limit
as 6-byte residual fields
- Addresses reconstructed from session context on receive side
- Net savings: 29 bytes per packet (overhead 106 → 77 bytes)
- FIPS_IPV6_OVERHEAD constant (77 bytes), effective_ipv6_mtu() updated
- 16 unit tests for round-trip fidelity, field preservation, error cases
Documentation:
- fips-wire-formats: DataPacket port header, port registry, IPv6 shim
format tables, updated encapsulation walkthrough and overhead budget
- fips-ipv6-adapter: FIPS_IPV6_OVERHEAD (77 bytes), updated MTU numbers,
TUN reader/writer flow with compression steps, impl status
- fips-session-layer: port-based service dispatch section, data transfer
description, impl status
- fips-intro: IPv6 adapter as port 256 service, node architecture updated
- fips-mesh-operation: packet size summary with compressed overhead
- DataPacket doc updated with port header and dispatch model
- session_wire.rs module doc: DataPacket Port Multiplexing section
Update 9 documentation files to match current implementation:
- Add missing rekey config section (node.rekey.*) and host mapping
section to fips-configuration.md
- Update Ethernet frame format from [type:1][payload] to
[type:1][length:2 LE][payload] in wire-formats and transport docs
- Fix Ethernet effective MTU from interface-1 to interface-3
- Mark rekey as Implemented in mesh-layer and session-layer status tables
- Change TCP default port examples from 443 to 8443
- Add rekey, persistent identity, host mapping, mesh size estimation to
README features and status sections
- Update chaos scenario count from 16 to 20, add rekey topology to
static test docs
Implement hop-by-hop ECN congestion signaling through the FMP layer,
transport-level congestion detection via kernel drop counters, and
chaos harness integration for end-to-end validation.
FMP/session ECN plumbing:
- Thread ce_flag parsed at link layer through dispatch_link_message,
handle_session_datagram, handle_session_payload, and
handle_encrypted_session_msg to session delivery
- Replace hardcoded false in session-layer record_recv() with actual
ce_flag, activating ecn_ce_count tracking in session MMP
ECN congestion detection and CE relay:
- Add EcnConfig (node.ecn.*) with configurable loss_threshold (5%)
and etx_threshold (3.0) for transit congestion detection
- Add send_encrypted_link_message_with_ce() that ORs FLAG_CE into FMP
header flags; original method delegates with ce_flag=false
- Compute outgoing_ce = incoming_ce || local congestion on next-hop
link, enabling hop-by-hop CE relay through transit nodes
IPv6 ECN-CE marking:
- Mark ECN-CE (0b11) in IPv6 Traffic Class on received DataPackets
before TUN delivery when FMP CE flag is set
- Only marks ECN-capable packets (ECT(0)/ECT(1)); Not-ECT packets
unchanged per RFC 3168
Transport congestion abstraction and UDP kernel drop detection:
- Add TransportCongestion struct to transport layer for transport-
agnostic local congestion indicators
- Replace tokio::UdpSocket with AsyncFd<socket2::Socket> using
libc::recvmsg() with ancillary data parsing
- Enable SO_RXQ_OVFL for kernel receive buffer drop counter on every
packet, wiring up previously-stubbed UdpStats.kernel_drops
- Add TransportDropState for per-transport delta tracking with 1s
tick sampling via sample_transport_congestion()
- Extend detect_congestion() with transport kernel drop check
alongside MMP loss metrics
Congestion monitoring and control:
- Add CongestionStats (ce_forwarded, ce_received, congestion_detected,
kernel_drop_events) to NodeStats with snapshot serialization
- Wire counters into forwarding path, session handler, and transport
drop sampling with rate-limited warn logging (5s interval)
- Expose congestion data in show_routing control query and
ecn_ce_count in show_mmp peer entries
- Add congestion counters to fipstop routing tab in two-column layout
Chaos harness integration:
- Add query_routing(), query_transports(), snapshot_all_congestion()
to chaos control module
- Add congestion/kernel-drop log analysis in logs module
- Add congestion-stress scenario: 10-node tree, 1 Mbps bandwidth,
5-10% netem loss, heavy iperf3 traffic
- Add IngressConfig for tc ingress policing with per-peer policer
filters simulating upstream bandwidth bottlenecks
- Add iperf3 JSON result capture to traffic manager for throughput
measurement across scenarios
- Add ECN A/B test scenarios (ecn-ab-on/off.yaml) with ingress
policing and comparison script
- Enable TCP ECN negotiation (tcp_ecn=1 sysctl) in container
entrypoint for end-to-end CE propagation
Tests:
- 10 ECN unit/integration tests: mark_ipv6_ecn_ce variants, CE relay
chain (3-node propagation), EcnConfig serde roundtrip
- 3 transport drop congestion detection unit tests
Documentation:
- Update fips-mesh-layer.md: replace outdated CE Echo stub with full
ECN Congestion Signaling section covering detection logic, CE relay,
IPv6 marking, session tracking, and monitoring counters
- Update fips-configuration.md: add node.ecn.* parameter table and
ecn block in complete reference YAML
- Update fips-transport-layer.md: add Congestion Reporting section
with TransportCongestion struct, congestion() trait method, and
per-transport status; document AsyncFd/recvmsg/SO_RXQ_OVFL in UDP
- Update chaos README: add congestion/ECN scenario docs, ingress
traffic control, and iperf3 JSON capture sections
- Update README.md: add ECN to features list and "What works today";
update transport and tooling entries
Implement TCP transport for FIPS enabling firewall traversal and serving
as the foundation for future Tor transport. This is the first
connection-oriented transport in the system.
Key design decisions:
- FMP header-based framing: reuses existing 4-byte FMP common prefix for
packet boundary recovery with zero framing overhead
- Session survives TCP reconnection: Noise/MMP/FSP state bound to npub,
not TCP connection; MMP liveness is sole authority for peer death
- Connect-on-send: fresh connection on first send, transparent reconnect
- close_connection() trait method for cross-connection deduplication cleanup
New transport files:
- src/transport/tcp/mod.rs: TcpTransport, connection pool, accept loop
- src/transport/tcp/stream.rs: FMP-aware stream reader (shared with Tor)
Modified: transport trait (close_connection), TcpConfig, TransportHandle
match arms, create_transports(), initiate_connection() for connection-
oriented links, cross-connection tie-breaker cleanup, design docs.
Tree announce loop and TCP stability fixes:
- Preserve tree announce rate-limit state across reconnection: carry
forward last_tree_announce_sent_ms when a peer reconnects so the
rate-limit window isn't reset to zero
- Drop oversize TCP packets at sender: pre-send MTU check returns
MtuExceeded instead of writing to the stream, preventing receiver-side
connection teardown and reset-reconnect cycles
Chaos harness:
- TCP transport support: tcp_edges/has_tcp/tcp_peers in SimTopology,
transport-aware config_gen with per-edge transport type, TCP port 443,
pure-TCP node support
- Include all non-Ethernet edges in directed_outbound()
- Fix netem/links log messages to say "IP-based" instead of "UDP"
- Add tcp-chain, tcp-only, and tcp-mesh scenario files
Static harness:
- Transport-aware config generation (get_default_transport, transport_port)
- TCP transport injection via Python post-processing
- Add tcp-chain topology and docker-compose profile
Update the default UDP bind port from 4000 to 2121 (decimal) and the
default Ethernet EtherType from 0x88B5 to 0x2121 across all source
code, documentation, configuration templates, test fixtures, and
scripts. Remove references to "IEEE 802 experimental range" since
0x2121 is not in that range.
Implement raw Ethernet transport using AF_PACKET SOCK_DGRAM on Linux
with EtherType 0x88B5 (IEEE experimental range) and 1-byte frame type
prefix (0x00=data, 0x01=beacon).
Transport implementation:
- EthernetConfig with interface, ethertype, MTU, buffer sizes, and
four independent discovery knobs (discovery, announce, auto_connect,
accept_connections)
- PacketSocket/AsyncPacketSocket wrappers with ioctl helpers for
interface index, MAC address, and MTU queries
- EthernetTransport with Transport trait impl, async start/stop/send,
receive loop dispatching data frames and discovery beacons
- Discovery beacons (34 bytes: type + version + x-only pubkey) with
DiscoveryBuffer for peer accumulation and dedup
- Atomic statistics counters (frames, bytes, errors, beacons)
- Platform-gated with #[cfg(target_os = "linux")]
Transport-layer discovery integration:
- Promote auto_connect() and accept_connections() to Transport trait
with default implementations and TransportHandle dispatch
- Extract initiate_connection() so both static peer config and
discovery auto-connect share the same handshake initiation path
- Add poll_transport_discovery() to the tick handler to drain
discovery buffers and auto-connect to discovered peers
- Enforce accept_connections() in handle_msg1() — transports with
accept_connections=false silently drop inbound handshakes
Node integration:
- create_transports() handles Ethernet named instances
- resolve_ethernet_addr() parses "interface/mac" address format
- transport_mtu() generalized for multi-transport operation
Test harness:
- VethPair RAII struct for veth pair lifecycle management
- Three #[ignore] integration tests requiring root/CAP_NET_RAW:
two-node handshake, data exchange, mixed transport coexistence
- Chaos harness: transport-aware topology model, VethManager for
veth pairs between Docker containers, Ethernet-aware config gen,
netem split (HTB+u32 for UDP, root netem for veth), transport-aware
link flaps and node churn with veth re-setup
- Container entrypoint waits for configured Ethernet interfaces
before starting FIPS (handles veth creation timing)
- New scenarios: ethernet-only (4-node ring), ethernet-mesh (6-node
mixed UDP+Ethernet with netem and link flaps)
Documentation:
- fips-transport-layer.md: Ethernet section, beacon discovery, WiFi
compatibility, updated discovery state, trait surface additions,
implementation status table
- fips-configuration.md: Ethernet parameter table, named instances,
peer address format, mixed UDP+Ethernet example, complete reference
- fips-wire-formats.md: Ethernet frame type prefix note
Rework top-level README: add badges, status/roadmap section, config
search path docs, minimal two-node example with transports, DNS setup
instructions with systemd-resolved and resolv.conf examples, and
connectivity test walkthrough.
Replace ASCII document-relationship diagram with SVG in design docs.
Change DNS resolver default from disabled to enabled (port 5354).
Update config merge to allow higher-priority configs to disable it.
Wire format diagrams:
- Add 24 SVG diagrams covering every FMP and FSP wire format: common
prefix, established frame headers, Noise IK handshake messages,
handshake flow, TreeAnnounce, AncestryEntry, FilterAnnounce,
LookupRequest/Response, SessionDatagram, Disconnect, SenderReport,
ReceiverReport, FSP complete message, SessionSetup/Ack/Msg3,
PathMtuNotification, CoordsRequired, PathBroken, and MtuExceeded
- Replace ASCII art in fips-wire-formats.md with SVG references
- Apply text edits to fips-mesh-layer.md, fips-mesh-operation.md,
fips-transport-layer.md, and fips-ipv6-adapter.md
Spanning tree dynamics:
- Add 12 topology SVG diagrams: node join (overview + 3-panel steps),
three-node convergence (4-panel), link addition with depth labels,
link removal, partition formation, and 6 real-world example diagrams
(office, mixed-link, two-site WAN topologies)
- Rewrite all code blocks to narrative prose with diagram references
- Add inline prior art attributions distinguishing Yggdrasil-derived
concepts from FIPS-novel contributions
- Add 3 new references (De Couto ETX, IEEE 802.1D, RFC 2328 OSPF) and
Prior Art summary
- Remove outdated sections: indirect partition note, integration test
gaps, DHT-based lookup reference
- Change "must elect a new root" to "must rediscover its new root"
Spanning tree design review (fips-spanning-tree.md):
- Rename "Root Election" to "Root Discovery" across docs
- Add "What Is a Spanning Tree?" introductory section
- Add parent selection intro explaining self-organization role
- Fix tree distance example: 4 hops, not 2
- Clarify timestamp field as advisory only
- Remove unimplemented ROOT_TIMEOUT and TREE_ENTRY_TTL from timing
parameters and implementation status tables
Bloom filter design review (fips-bloom-filters.md):
- Add "What Is a Bloom Filter?" intro section
- Rewrite Purpose section to frame filters as routing path identification
- Correct FPR analysis (old values were 3-50x overstated)
- Add Filter Occupancy Model based on network size and tree position
- Fix filter expiration to describe actual MMP-based cleanup
- Combine Scale Considerations with Size Classes after Wire Format
- Fix stale FPR values in src/bloom/mod.rs comments
Session layer review (fips-session-layer.md):
- Add inline prior art attributions: Noise Protocol Framework, WireGuard,
DTLS (RFC 6347), IKEv2 (RFC 7296), RFC 1191 PMTUD, Yggdrasil, NIP-44
- Replace warmup state machine ASCII art with SVG diagram
- Convert CoordsWarmup wire format code block to prose
- Add External References section with full citations
Level 5 implementation doc cleanup:
- Delete fips-software-architecture.md (redundant with protocol layer docs)
- Delete fips-state-machines.md (Rust tutorial, not protocol design)
- Add fipsctl command reference to README.md
- Update cross-references in fips-intro.md, docs/design/README.md,
fips-transport-layer.md, fips-configuration.md
Fixes:
- Correct fd::/8 to fd00::/8 in fips-session-layer.md,
fips-identity-derivation.svg, and fips-node-architecture.svg
- Fix config example MTU: 1197 → 1472 in fips-configuration.md
File organization:
- Move all SVG diagrams into docs/design/diagrams/ subdirectory
- Update all diagram references to use new paths
Cost-based parent selection:
- Replace depth-only parent selection with effective_depth = depth + link_cost
- link_cost computed from locally measured MMP metrics: etx * (1.0 + srtt_ms / 100.0)
- Prevents bottleneck subtrees in heterogeneous networks where a LoRa link
at depth 1 would otherwise always beat fiber at depth 2
- Configurable hysteresis (default 0.2) prevents marginal parent switches
- Configurable hold-down timer (default 30s) suppresses re-evaluation
after parent switch
- Mandatory switches (parent lost, root change) bypass both safeguards
- Link costs passed as HashMap parameter to keep TreeState pure
Periodic re-evaluation:
- evaluate_parent() was only called on TreeAnnounce receipt or parent loss;
after tree stabilization, link degradation went undetected
- Added timer-based re-evaluation (reeval_interval_secs, default 60s) that
calls evaluate_parent() from the tick handler with current MMP link costs
- Respects existing hold-down and hysteresis safeguards
- Short-circuits when disabled or <2 peers
Design documentation:
- Update 7 design docs to reflect cost-based parent selection
- Replace depth-only algorithm descriptions with effective_depth model
- Replace rejected cumulative path cost spec with local-only design rationale
- Rewrite Example 2 (heterogeneous links) for local-only cost model
- Update config docs: parent_switch_threshold replaced by parent_hysteresis,
hold_down_secs, reeval_interval_secs
Chaos simulation enhancements:
- fips_overrides with deep merge for per-scenario FIPS config customization
- Explicit topology algorithm for deterministic test graphs
- Control socket querying via fipsctl for tree/MMP snapshot collection
- Edge existence validation in netem manager
- Per-link netem policy overrides
- 9 new chaos scenarios covering cost avoidance, depth-vs-cost tradeoffs,
stability, mixed topologies, periodic re-evaluation, and bottleneck parent
12 new unit tests, 667 total passing, clippy clean.
Gate peer_inbound_filters() to only collect from tree peers (parent
and children), so outgoing filter computation merges only tree-sourced
information. All peers still receive FilterAnnounce messages and store
filters locally for routing queries — the restriction is only on what
gets merged into outgoing filters.
This prevents bloom filter saturation where mesh shortcuts cause every
node's filter to converge toward the full network. With tree-only
merge, filters contain subtree (from children) + complement (from
parent) + single-hop mesh views.
Implementation:
- Add is_tree_peer() helper to determine tree parent/child relationship
- Gate peer_inbound_filters() to tree peers only (single control point)
- Trigger bloom filter exchange on tree relationship changes
- Add est_entries, set_bits, fill ratio, and tree_peer fields to
FilterAnnounce send/receive debug logs
- Add test_bloom_filter_split_horizon test verifying directional
asymmetry: upward filters contain only the child's subtree, downward
filters contain only the complement
- Add print_filter_cardinality diagnostic helper for test inspection
Design docs:
- fips-bloom-filters.md: Add directional asymmetry and mesh peer filter
subsections, update per-peer filter model, saturation mitigation,
implementation status table
- fips-mesh-operation.md: Update filter propagation description, add
directional asymmetry, tree relationship change trigger
- fips-intro.md: Rewrite bloom propagation paragraph for tree-only merge
Rename FIPS Link Protocol (FLP) to FIPS Mesh Protocol (FMP)
The "Link Protocol" name understated the layer's scope — spanning tree
construction, bloom filter routing, greedy forwarding, and mesh-wide
coordination go well beyond link-level concerns. Rename fips-link-layer.md
to fips-mesh-layer.md, update FLP→FMP throughout docs and source code
(FLP_VERSION→FMP_VERSION, wire.rs, rx_loop.rs, spanning_tree.rs).
New SVG illustrations
- Protocol stack: color-coded layer diagram replacing ASCII art
- OSI mapping: side-by-side comparison with traditional networking layers
- Bloom filter propagation: 6-node tree with sender-colored filter boxes
showing split-horizon computation per link
- Routing decision flowchart: 5-step priority chain with candidate ranking
by tree distance and link performance
- Coordinate discovery: sequence diagram showing LookupRequest propagation,
response caching, and SessionSetup cache warming
Redesigned existing SVGs
- Architecture overview: uniform node layout, U-shaped encrypted link
connectors, separate end-to-end session line
- Node architecture: split Router Core into FSP and FMP layers, reorganize
transports into Overlay/Shared Medium/Point-to-Point categories
- Identity derivation: wider boxes, visible encode arrow, dashed npub line
fips-intro.md revisions
- Add inline references to prior work: Yggdrasil/Ironwood for coordinate
routing, Noise Protocol Framework for IK handshakes, WireGuard for
index-based session dispatch, Wikipedia for bloom filters, split-horizon,
and greedy embedding
- Add explanatory paragraphs after bloom filter diagram describing
split-horizon filter computation and candidate selection behavior
- Simplify transport abstraction language, remove I2P/LoRa references
- Fix LookupRequest wording ("propagates" not "floods"), note intermediate
node coordinate caching on lookup responses
- Rewrite architecture overview prose to match redesigned diagrams
SessionAck previously only carried the responder's coordinates
(src_coords). When the return path diverged from the forward path
(e.g., after tree reconvergence), transit nodes on the return path
lacked the initiator's coordinates and couldn't route the SessionAck
back, causing handshake timeouts.
Add dest_coords (initiator's coordinates) to the SessionAck wire
format, mirroring SessionSetup's design. Transit nodes now cache both
endpoints' coordinates when forwarding a SessionAck, making the return
path self-sufficient regardless of path asymmetry.
Root cause confirmed by churn-20 sim log analysis: the n04-n14
handshake failure was caused by n15 (return-path transit) lacking
n04's coordinates, not by stale tree routes through a downed node.
fips-link-layer.md:
- Rewrite Liveness Detection: explicit Heartbeat (0x51) with 10s interval
and 30s dead timeout replaces vague gossip-as-heartbeat description
- Add Auto-Reconnect section: MMP dead timeout triggers retry with
unlimited backoff for auto_reconnect peers
- Add Handshake Message Retry section: link + session layer resend with
exponential backoff within timeout window
- Add Heartbeat to Link Message Types table
- Update Implementation Status with three new implemented features
fips-configuration.md:
- Add handshake_resend_interval_ms, handshake_resend_backoff,
handshake_max_resends to rate_limit table
- Add heartbeat_interval_secs, link_dead_timeout_secs to general table
- Add peers[].auto_reconnect to peers table
- Note auto-reconnect bypasses max_retries in retry section
- Update complete reference YAML with all new parameters
fips-wire-formats.md:
- Rename 0x51 from reserved Keepalive to implemented Heartbeat
- Update Disconnect reason 0x07 to Heartbeat liveness timeout
testing/chaos/README.md:
- Add runner.log to output files
- Add Directed Outbound Configs subsection
Implement hybrid coordinate cache warming strategy: piggyback coords
via CP flag when they fit within transport MTU, send standalone
CoordsWarmup (0x14) message when they don't. On CoordsRequired or
PathBroken receipt, send CoordsWarmup immediately with source-side
rate limiting (default 2s per destination, configurable).
- Add CoordsWarmup = 0x14 session message type (empty body, CP flag)
- Add send_coords_warmup() following send_session_msg() pattern
- Restructure send_session_data() to send standalone warmup before
data packet when piggybacked coords exceed MTU
- Add immediate CoordsWarmup response in handle_coords_required()
and handle_path_broken() with per-destination rate limiting
- Add coords_response_interval_ms config (node.session)
- Add RoutingErrorRateLimiter::with_interval() constructor
- Zero transit-path changes: existing try_warm_coord_cache() handles
CoordsWarmup identically to CP-flagged data packets
- Update design docs (session layer, wire formats, mesh operation,
configuration)
FIPS_OVERHEAD was 150 but had two bugs: the session AEAD tag (16 bytes)
was listed in the comment but missing from the arithmetic, and the
coordinate budget (~60 bytes) was undersized and didn't belong in a
constant representing fixed data path overhead.
Corrected to 106 bytes (the actual fixed overhead without coordinates).
This increases effective_ipv6_mtu from 1322 to 1366 for standard
Ethernet, well above the IPv6 minimum of 1280.
Added a guard in send_session_data() that computes the total wire size
with coordinates before committing to include them. If adding coords
would exceed the transport MTU, the CP flag is skipped and the warmup
counter is not decremented. This prevents silently producing oversized
packets at tree depth 2+.
Updated design docs (ipv6-adapter, wire-formats, mesh-operation) with
corrected overhead values.
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).
- 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.
Sync fips-configuration.md with code changes from sessions 101-102:
- Replace route_size with identity_size (cache merge)
- Update cache section description (single cache, not dual)
- Add idle_timeout_secs and coords_warmup_packets to session table
- Add both to Complete Reference YAML
- Fix UDP MTU default in Complete Reference (1197 → 1280)
Add dual-approach MTU handling to prevent TCP connections from hanging
when packets exceed the transport MTU after FIPS encapsulation.
ICMPv6 Packet Too Big:
- Generate RFC 4443 PTB messages for oversized packets at TUN outbound
- Inject back via TUN for local delivery to the application
- Per-source rate limiting (100ms interval, 10s entry expiry)
- MTU check in handle_tun_outbound before session encapsulation
TCP MSS Clamping:
- Intercept SYN packets in run_tun_reader() (outbound)
- Intercept SYN-ACK packets in TunWriter (inbound)
- Clamp MSS option to fit within effective MTU (transport - 127 overhead)
- Recalculate TCP checksum after modification
Code organization:
- ICMP, TCP MSS, and rate limiter modules in upper/ alongside existing
protocol-specific packet handling (dns.rs, tun.rs)
- Shared FIPS_OVERHEAD constant (127 bytes) and effective_ipv6_mtu()
function in upper/icmp.rs
- Node::effective_ipv6_mtu() delegates to the shared function
- run_tun_reader() accepts actual transport MTU from config
Example config corrections:
- UDP transport MTU set to 1472 across all configs (correct max UDP
payload for standard Ethernet: 1500 - 20 IPv4 - 8 UDP)
- Startup logging of effective MTU and max MSS values
Add fips-identity-derivation.svg showing the derivation chain from
pubkey to npub, node_addr, and IPv6 address with protocol roles and
privacy boundary. Replaces the code block in Node Address Derivation
with the diagram and consolidated descriptive text.
- fips-architecture.md → fips-software-architecture.md with all
cross-references updated (4 files)
- fips-transport-abstraction.svg → fips-node-architecture.svg, moved
from Transport Abstraction section to Architecture Overview in
fips-intro.md
- Added descriptive paragraph for node architecture diagram covering
three-layer design (application interfaces, router core, transports)
Replace three ASCII art diagrams in fips-intro.md with SVG images:
- Architecture overview: 5-node 4-hop path with layered node boxes
- Mesh topology: 8-node network with spanning tree highlighted
- Transport abstraction: full node stack with 10 transport plugins
Add src_addr to SessionDatagram envelope (34-byte header: msg_type +
src_addr + dest_addr + hop_limit) so transit routers can route error
signals back to the packet's originator.
Reclassify CoordsRequired/PathBroken as link-layer error signals
(plaintext inside SessionDatagram) rather than e2e encrypted session
messages. Transit routers generate these when forwarding fails and
route them to src_addr; if source is also unreachable, drop silently.
Remove redundant src_addr/dest_addr/hop_limit from SessionSetup,
SessionAck, and DataPacket (now in envelope). DataPacket header
reduced from 36 to 4 bytes. Remove PathBroken.original_src.
Fix routing loop vulnerability: gate bloom filter path on having
cached dest_coords to prevent blind forwarding between peers.
Simplify select_best_candidate() to require coordinates.
Fix gossip protocol type codes (0x11->0x20, 0x12->0x30, 0x13->0x31)
for consistency across all design docs.
All 5 design docs updated and cross-checked for consistency.
335 tests pass, zero warnings.
Add the full next-hop routing algorithm to Node::find_next_hop():
- Local delivery, direct peer, bloom filter candidates, greedy tree
routing fallback, with (link_cost, tree_distance, node_addr) ordering
- select_best_candidate() scores by peer→dest distance (not us→peer)
with self-distance check to prevent routing loops
- TreeState::find_next_hop() for greedy tree routing with progress
guarantee
- ActivePeer::link_cost() placeholder (constant 1.0) for future link
quality metrics
Add routing tests including 100-node all-pairs reachability simulation
(9900/9900 delivered, 0 loops, avg 4.0 hops, max 8).
Update fips-routing.md to reflect bloom filter routing as the primary
forwarding mechanism, with greedy tree routing as fallback during
convergence windows.
Noise IK parity fix:
- Pre-message hash normalizes responder static key to even parity (0x02)
so initiator and responder hash chains match regardless of actual parity
- ECDH uses shared_secret_point() + SHA-256(x-only) instead of
SharedSecret::new() which includes a parity-dependent version byte
- Fixes handshake failure for ~50% of keys when initiator has only npub
Graceful disconnect protocol (link message 0x50):
- DisconnectReason enum with 8 reason codes
- Disconnect struct with encode/decode
- send_encrypted_link_message() reusable helper
- handle_disconnect() with immediate peer removal
- send_disconnect_to_all_peers() called during Node::stop()
Cross-connection fix in handle_msg1():
- addr_to_link check now distinguishes inbound duplicates (reject) from
outbound links (cross-connection, allow and resolve via tie-breaker)
- remove_link() only clears addr_to_link if entry maps to same link_id
- Link cleanup and addr_to_link restoration in cross-connection branches
Handshake timeout cleanup:
- RX loop uses tokio::select! with 1-second interval tick
- check_timeouts() scans for stale (>30s) and failed connections
- cleanup_stale_connection() removes all associated state
Tests: 279 passing (4 new: cross-connection, stale cleanup, failed
cleanup, odd-parity handshake)
Add test_run_rx_loop_handshake exercising the full packet dispatch
path (UDP → channel → run_rx_loop → process_packet → handler) using
tokio::select! with timeout to release &mut self for assertions.
Correct session layer documentation: sessions are always established
between communicating nodes regardless of adjacency, not only for
non-adjacent traffic. Add adjacent-peer encryption flow example,
fix table description, rename Link Layer subsection to "Hop-by-Hop".
267 tests pass (266 existing + 1 new).
