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Johnathan Corgan
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The previous default configured systemd-resolved with `resolvectl dns fips0 [<fips0_addr>]:5354`, intended to bypass an Ubuntu 22 systemd 249 interface-scoping bug. That target collides with the daemon's mesh-interface filter on Linux: when an IPv6 packet's destination belongs to a non-loopback interface, the kernel attributes the packet to that interface in IPV6_PKTINFO (ipi6_ifindex == fips0) even though loopback delivery is used (tcpdump shows lo). The mesh-interface filter sees arrival_ifindex == mesh_ifindex and silently drops every query at trace level — invisible to operators at the default debug level. Net effect on stock deployments: every .fips query on systemd-resolved hosts was silently dropped. Daemon side ----------- - Default `dns.bind_addr` changes from "::" to "::1" (IPv6 loopback only). The mesh-interface filter is then defanged on the default path because loopback isn't reachable from mesh peers. The filter remains in place defensively for operators who explicitly bind "::" to expose a mesh-reachable responder. fips-dns-setup backend unification ---------------------------------- - New `try_global_drop_in` backend writes /etc/systemd/resolved.conf.d/fips.conf with DNS=[::1]:5354 and Domains=~fips. Inserted ahead of `try_resolvectl` in the dispatch chain. The standard loopback path has no interface scoping, so ipi6_ifindex reports lo and the filter passes. - All other backends now target [::1]:5354 to match the daemon's default IPv6-loopback bind: - try_dns_delegate writes DNS=[::1]:5354 - try_dnsmasq writes server=/fips/::1#5354 - try_nm_dnsmasq writes server=/fips/::1#5354 - Fixed dns-delegate file path: was /etc/systemd/dns-delegate/, must be /etc/systemd/dns-delegate.d/ (with .d suffix). systemd-resolved silently ignored the previous path. - fips-dns-teardown handles the new global-drop-in backend in cleanup. - The legacy resolvectl per-link backend stays as a fallback, documented to require careful daemon bind_addr coordination. fips-gateway upstream pairing ----------------------------- - gateway.dns.upstream default changes from 127.0.0.1:5354 to [::1]:5354 to match the daemon's default bind. Linux IPv6 sockets bound to explicit ::1 do not accept v4-mapped traffic, so the old default would have caused the gateway's startup DNS reachability probe to time out and systemd to restart-loop the service. - Operators who set a non-default daemon `dns.bind_addr` must also set `gateway.dns.upstream` to match — documented inline. Documentation ------------- - packaging/common/fips.yaml and packaging/openwrt-ipk fips.yaml examples updated; rationale for the bind_addr choice and the daemon/gateway pairing recorded inline. Test coverage ------------- - testing/dns-resolver/test.sh: real-fipsd end-to-end scenario added. Builds fipsd in a Debian 12 builder image (cached), runs the daemon with a real TUN in a privileged container, configures DNS via the setup script, and asserts `dig @127.0.0.53 AAAA <npub>.fips` returns AAAA. Refactored as a parameterized helper running across Debian 12/13 and Ubuntu 22/24/26 (5 e2e scenarios). Backend-aware assertions: on systemd >= 258 the expected backend is dns-delegate; on older systemd it's global-drop-in. Strict content checks fail CI on any [::1]:5354 drift. fips-gateway also exercised in the debian12 scenario to lock the gateway-upstream pairing. Renamed all "fipsd" references to "fips" (project convention). - testing/deb-install/ (new harness): builds the actual .deb via cargo-deb in a Debian 12 builder image (cached), installs via apt across each target distro, verifies maintainer scripts, conffile placement, binary placement, and end-to-end .fips resolution after start. Also exercises fips-gateway against the installed daemon to verify the gateway/daemon default pairing on a real .deb path. - This is the test layer that was missing — the previous harness only verified config files were written, never that queries reached the daemon. Verified: dns-resolver 78/78 assertions, deb-install 55/55 assertions across all 5 distros (debian:12, debian:trixie, ubuntu:22.04, ubuntu:24.04, ubuntu:26.04).
FIPS Testing
Integration and simulation test harnesses for FIPS, using Docker containers running the full protocol stack.
Test Harnesses
static/ -- Static Docker Network
Fixed topologies with manual scripts for building, config generation, connectivity tests (ping, iperf), and network impairment (netem). Useful for deterministic debugging and validating specific topology configurations.
| Topology | Nodes | Transport | Description |
|---|---|---|---|
| mesh | 5 | UDP | Sparse mesh, 6 links, multi-hop |
| chain | 5 | UDP | Linear chain, max 4-hop paths |
| mesh-public | 5+1 | UDP | Mesh with external public node |
| tcp-chain | 3 | TCP | Linear chain over TCP (port 8443) |
| rekey | 5 | UDP | Rekey integration test topology |
tor/ -- Tor Transport Integration
End-to-end Tor transport testing with Docker containers running real Tor daemons. Requires internet access for Tor bootstrapping.
| Scenario | Description |
|---|---|
| socks5-outbound | Outbound SOCKS5 connections through Tor to clearnet peer |
| directory-mode | Inbound via HiddenServiceDir onion service (co-located) |
nat/ -- NAT Traversal Lab
Real Docker NAT traversal tests for the Nostr/STUN bootstrap path,
using router containers with iptables-based NAT, a local Nostr relay,
and a local STUN responder.
| Scenario | Description |
|---|---|
| cone | Two NATed peers establish a UDP traversal path |
| symmetric | UDP traversal fails under symmetric NAT, TCP fallback wins |
| lan | Peers on the same LAN prefer local addresses over reflexive |
chaos/ -- Stochastic Simulation
Automated network testing with configurable node counts, topology algorithms (random geometric, Erdos-Renyi, chain, explicit), and fault injection (netem mutation, link flaps, traffic generation, node churn). 20 scenarios covering general stress testing, cost-based parent selection, mixed link technologies (fiber/Bluetooth/WiFi), transport-specific validation (UDP, TCP, Ethernet), and ECN/congestion testing. Scenarios are defined in YAML and executed via a Python harness that manages the full lifecycle: topology generation, Docker orchestration, fault scheduling, log collection, and analysis.