Replace the 3-message XK handshake with XX for FSP session establishment.
XX requires no prior knowledge of the peer's static key — the responder's
identity is revealed in msg2, the initiator's in msg3.
Key changes:
- session.rs: XX initiator/responder, post-handshake identity verification
using x-only key comparison (parity-independent for npub compatibility),
negotiation payload in msg2/msg3 (FSP version [0,0], features=0)
- Rekey: switched from XK to XX for FSP rekey handshake
- timeout.rs: suppress msg1 resends when target peer is already promoted,
preventing cross-connection session mismatch from duplicate handshakes
- Test template: discovery backoff 3s and handshake timeout 10s for
faster convergence in integration tests
- Integration test timeouts restored to 45s (ping) and 60s (rekey)
Squashed commits:
- Switch FSP handshake from Noise XK to XX
- Fix integration test convergence by reducing discovery backoff
- Fix cross-connection session mismatch from msg1 resend
- Fix FSP identity verification parity mismatch
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.
Update the external pub node (vps-chi at 217.77.8.91) to use its
real persistent npub instead of a fabricated test key. Remove the
unnecessary nsec from the external node definition.
Implement periodic full rekey at both protocol layers using fresh DH
key exchanges. Uses the existing K-bit flag (FLAG_KEY_EPOCH /
FSP_FLAG_K) to coordinate cutover between peers.
FMP layer (IK pattern):
- ActivePeer gains rekey state: pending/previous sessions, K-bit epoch
tracking, drain window, dampening timer
- Handshake state stored on ActivePeer with msg1 sent on existing link
- Encrypted frame handler detects K-bit flips, promotes pending
sessions, falls back to previous session during drain
- Handshake handlers distinguish rekey from new connections using
addr_to_link lookup with identity-based fallback
- Free all session indices (current, rekey, pending, previous) on
peer removal
FSP layer (XK pattern):
- SessionEntry gains parallel rekey fields with XK-specific state
for the 3-message handshake
- Route availability check before FSP rekey initiation
- Encrypted session handler adds K-bit flip detection and dual-session
decrypt fallback
- SessionSetup/Ack/Msg3 handlers extended for rekey paths
Defense-in-depth:
- Consecutive decryption failure detector (threshold=20) triggers
forced peer removal instead of waiting for link-dead timeout
- Identity-based rekey detection as fallback when addr_to_link
doesn't match (e.g., TCP ephemeral ports)
Configuration: RekeyConfig with enabled flag, after_secs (default 120),
and after_messages (default 65536) thresholds.
Logging: info for successful K-bit cutover completions, warn for
failures, debug for intermediate handshake steps, trace for routine
operations (resends, drain cleanup).
Rekey lifecycle:
1. Timer/counter fires -> initiator starts new handshake
2. Old session continues handling traffic during handshake
3. Handshake completes -> initiator cuts over, flips K-bit
4. Responder sees flipped K-bit -> promotes new session
5. Both keep old session for 10s drain window
6. After drain, old session discarded
Integration test: Docker-based multi-phase test exercising both FMP
and FSP rekey with aggressive timers (35s). Verifies connectivity
across all 20 directed pairs survives two consecutive rekey cycles.
Includes rekey topology, docker-compose profile, and CI matrix entry.
Increase ping test convergence wait from 3s to 5s for CI reliability.
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.
Johnathan Corgan