- Don't probe lanes on a tunnel idle in both directions, and don't count lane
probes or their acks as tunnel traffic. A lane's own keepalive was keeping
idle tunnels from ever being dropped by tunnels.drop_inactive.
- Accept a recv_error from an up lane's target. The peer answers lane traffic
from the lane socket it arrived on, and the spoof guard only accepted the
base remote, so recv_errors for lane traffic were ignored.
- Keep the probe generation across a lane reset, so an ack for a probe sent
before a roam can't promote the lane on the new path.
- Bring handshake.proto in line with payload.go: field 3 is reserved and
TxLanes is field 4.
Lanes used to be separate HostInfos, each with its own handshake, its own
half-established states, its own lifetime and its own slot bookkeeping. That
bought nothing: a lane is the same tunnel over a different underlay 5-tuple.
Derive lane sessions instead. Noise leaves us with A.eKey == B.dKey, so both
sides HKDF-expand the same two keys with the same per-lane label and land on a
matched pair without exchanging anything. Lanes now cost no handshake, have no
half-established state, and die exactly when their base tunnel does. Which lane
a packet belongs to rides the low byte of the nebula header's Reserved field,
inside the AEAD's associated data.
Receiving on a lane needs no permission, since the session exists the moment the
base handshake completes. Sending on one needs proof the new 5-tuple works, so a
lane stays down until a probe on it is acked and falls back to the base tunnel
the moment it stops being acked. Probing is demand-driven off the connection
manager's per-tunnel traffic tick: a peer we exchange a trickle with never costs
more than its base tunnel, however many lanes are configured. The ack rides the
base session on purpose, so a broken reverse lane can't fail a working one.
Because the data now rides lane counters, the rehandshake, exhaustion and
swap-primary checks take the max counter across the base session and its lanes;
otherwise the base counter would sit near zero while a lane ran its keys past
the nonce ceiling.
Removes OutboundLaneTimer, EnsureLanes, startLaneHandshake, completeLane,
completeLaneResponder, makeLaneTrafficDecision and the lane fields on HostInfo.
Handshake payload field 3 (the per-lane handshake index) is permanently
reserved; peers advertise a TxLanes count instead.
Fields 6 and 7 are reserved for work in progress, so the multiport lane
adverts move up to 9 and 10. Both are still single-byte tags, so the
encoded payload size does not change.
Also emit the lane fields after CertVersion so MarshalPayload stays in
ascending field-number order, matching what protoc-gen-go would produce
and keeping the hand-built expectations in payload_test.go
straightforward.
Field numbers are the only thing that identifies a lane advert, so a node
on this build and one on the previous numbering will each skip the other's
adverts as unknown fields and fall back to a single vanilla tunnel.
Wade Simmons