Extend the gateway integration suite with three previously unexercised
runtime paths. All three share testing/static/scripts/gateway-test.sh
and testing/static/docker-compose.yml so they land as one commit.
6A — UDP port forwarding runtime path. Add udp 18081 -> [fd02::20]:8081
to inject_gateway_config() and a phase-7 case where gw-client runs an
inline Python UDP echo server bound [::]:8081 and gw-server sends a
UDP probe to [GW_MESH_IP]:18081 via inline python3, asserting the
echoed payload prefix. The config layer already accepted proto: udp
(test_port_forwards_same_port_different_proto_ok) but the UDP NAT
rule shape and conntrack handling differ from TCP and were unverified.
Uses Python rather than socat because fips-test:latest does not ship
socat; nc -u IPv6 round-trip semantics are messier than a Python
one-liner.
6B — Second simultaneous TCP forward. Add tcp 18082 -> [fd02::20]:8081
alongside the existing 18080 forward. Phase 7 now greps the daemon's
nft DNAT table for all three rules (18080, 18082, 18081) and runs
HTTP fetches through both TCP forwards with distinct backend payloads
(inbound-forward-ok vs inbound-forward-ok-2) so a misrouted response
fails the assertion.
11A — Concurrent multi-client flows. Add gw-client-2 service to
docker-compose mirroring gw-client (IPv6 fd02::21, IPv4 172.20.1.21).
Phase 3 sets the fd01::/112 route on both. Phase 4 issues DNS lookups
from both, asserts they receive distinct virtual IPs, and queries the
gateway control socket (show_mappings) to confirm exactly 2 active
mappings (5-attempt retry loop tolerates snapshot-publish lag). Phase
5 launches both curl requests concurrently as background processes,
asserts each response. Validates concurrent NAT mappings, pool
contention, proxy NDP under simultaneous LAN-client traffic — all
real-world deployment shape that was not pinned.
Phase 8 reclamation timing unchanged (TTL=5s, grace=5s, 25s wait
covers both mapping ticks generously even with a slight stagger).
Mesh peers can now reach a configured host:port on the gateway's LAN
via static port-forward rules on fips-gateway. Mirror of the outbound
LAN gateway (IDEA-0079 / TASK-2026-0056).
Config: new gateway.port_forwards list of { listen_port, proto,
target } entries. Targets are SocketAddrV6 — IPv4 is rejected at
parse time. Validation rejects zero listen ports and duplicate
(listen_port, proto) pairs.
NAT: NatManager gains a port_forwards field and set_port_forwards()
setter, rebuilt in the same atomic rustables batch as the address
mappings. Each forward emits a prerouting DNAT rule keyed on
(iifname fips0, nfproto ipv6, l4proto, tcp/udp dport) that rewrites
destination address and port via Nat::with_ip_register +
with_port_register. When any forwards are configured, a single
LAN-side masquerade is installed on (iifname fips0, oifname
lan_interface, nfproto ipv6) so the LAN host sees the gateway as
source and replies flow back through conntrack. This rule is
distinct from the existing oifname fips0 masquerade that serves the
outbound pool.
Binary: fips-gateway validates port_forwards at startup and calls
set_port_forwards after NatManager construction; startup failure
cleans up the nftables table before exiting.
Test: extend testing/static/scripts/gateway-test.sh with Phase 7
that runs a marker HTTP server on the LAN-side client (fd02::20:8080)
and, from the mesh peer, curls the gateway's fips0 address on port
18080 to exercise the full DNAT + LAN masquerade path. The
LAN-side HTTP server is started with 'docker exec -d' plus a
bind-ready poll on ss; 'docker exec bash -c "cmd &"' does not
keep the child alive past the exec session even with nohup.
Test-infra: ci-local.sh now builds/clippies/tests with
--features gateway, matching GitHub CI. Without this the release
fips-gateway binary silently stays stale across runs, since
cargo build --release alone does not compile the gateway bin.
Verified locally: cargo test --features gateway --lib (991 pass),
clippy + fmt clean, full testing/ci-local.sh green (21/21 suites
in 8m36s, including the new gateway Phase 7).
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.
Johnathan Corgan