The interop harness only tested a full mesh, where every pair is a direct
one-hop FMP link. That left multi-hop forwarding, routing, coordinate
handling, and mesh-size estimation untested across versions.
Add an opt-in multi-hop topology and three new checks:
- generate-configs.sh: FIPS_INTEROP_EDGES selects an explicit undirected
edge list instead of the full mesh, with symmetric peering, connectivity
validation (no isolated node, graph connected), and per-node degree plus
edge metadata in nodes.env. Unset means full mesh, unchanged.
- interop-test.sh: a --topology flag with a built-in multihop-3v-cycle
(six nodes, two of each version, one cycle, two leaves). The per-node
peer check now expects each node's adjacency degree rather than N-1, and
the all-pairs ping now also exercises cross-version forwarding over
non-adjacent pairs. Adds a control-differential data-plane continuity
stream across the rekey window (Phase 5b) and a strict plus/minus 25
percent mesh-size convergence check (Phase 7).
- interop-stress.sh: forward --topology through to the per-rep driver
(mutually exclusive with a positional node-spec).
Phase 1 makes the strict retrying ping authoritative. The convergence
detector (one fully-clean, no-retry sweep of every directed pair) is now an
advisory settle-wait whose timeout is non-fatal; the strict retrying ping
decides pass/fail, matching how the post-rekey phases already work. Under
packet loss a clean no-retry sweep of a large mesh is statistically unlikely
even when the mesh is healthy (30 pairs at 2 percent loss leaves only about
55 percent of sweeps clean), so the detector otherwise falsely failed runs
whose strict ping reported full reachability. CONVERGENCE_TIMEOUT is now
env-overridable and defaults to 90s for larger meshes under loss.
Full-mesh runs are unaffected. Validated end-to-end with the
multihop-3v-cycle topology across three versions: all 30 directed pairs
reachable including multi-hop routed pairs, zero data-plane loss through
both rekey cutovers, and mesh-size converging to the true node count on
every node.
Johnathan Corgan