Complete the control-plane read-isolation work: every pure-read show_*
query now renders in the control accept task from published read
snapshots, so none round-trips the data-plane receive loop. Only the
mutating connect/disconnect commands still reach that loop.
Three subsystem snapshots are published via ArcSwap and served through the
read handle's snapshot_dispatch:
- A routing read view (spanning tree, bloom filters, coordinate cache,
identity cache, and the discovery F-queue summary scalars), published
from the tick, serving show_tree/show_bloom/show_cache/show_routing/
show_identity_cache.
- A per-entity read view (peers, sessions, links, connections, transports,
and the MMP link/session views) as Vec<Arc<Row>> tables reconciled
against the prior snapshot so a republish reuses unchanged rows by
pointer and re-allocates only changed or new rows, keeping the per-tick
publish cost bounded as the peer/session count grows. Serves
show_peers/show_sessions/show_links/show_connections/show_transports/
show_mmp.
- The stats snapshot is extended with the peer-ACL status and a per-peer
metadata map (is_active, npub, display name), resolved at publish time,
serving show_acl and the two per-peer stats queries.
Display names and other cross-subsystem fields are resolved at publish
time; time-relative fields are derived at render time from captured
absolute timestamps, so rendered output is byte-identical to the prior
on-loop handlers, which are retained as the equality oracle.
With every read query served off-loop, the show_* branch is removed from
the rx_loop control handler and the now-dead on-loop dispatcher deleted.
The snapshot projections are forward-compatible with the later structural
extraction of the derived-state and session tables: they become thin
views over the extracted types without changing the read-handle interface.
Introduce a read-snapshot plane so pure-snapshot control queries render in
the control-socket task instead of round-tripping the rx_loop, removing the
head-of-line coupling that let a busy or slow rx_loop time out fipsctl and
fipstop observability.
- ControlReadHandle: a cloneable bundle the control accept loop holds, over
the node's already-shared NodeContext and MetricsRegistry plus an
ArcSwap-published StatsSnapshot. A snapshot_dispatch seam serves cut-over
commands off-loop and falls through to the rx_loop for the rest, keeping
the rx_loop's ownership of Node intact.
- StatsSnapshot is published from the tick (the natural and sole mutator of
stats_history), carrying the history rings plus the scalar gauges and
counts show_status reports. Readers serve the latest snapshot
unconditionally, with staleness bounded by the tick interval and no
IO_TIMEOUT-coupled fallback.
- Off-loop now: show_status, show_stats_history, show_stats_all_history,
show_listening_sockets, show_stats_list, and a new counter-only
show_metrics (exposed as fipsctl "stats metrics", the enabler for a
Prometheus scraper at no hot-path cost). Queries that need live per-entity
state (peers, links, sessions, routing, and the per-peer stats variants)
stay on the rx_loop path pending later phases.
Quartet green; forward-merge to next verified clean.
The per-transport TCP inbound cap was hardwired to 256 and never read
node.limits.max_connections, so raising max_connections was a silent
no-op for inbound TCP. Resolve the effective cap with precedence:
explicit per-transport max_inbound_connections, then node-wide
max_connections, then the built-in default of 256. Established peers
remain bounded node-wide by add_connection, so deriving the per-transport
raw-accept ceiling from max_connections does not admit more real peers
across multiple transports.
Add effective_max_inbound on the TCP transport with a node_max_connections
setter wired from create_transports, plus a precedence unit test.
Estimate the OR-union cardinality over self plus every connected peer's
inbound filter, dropping the parent/child tree gating in
compute_mesh_size. Filter propagation is split-horizon, so cross-links
advertise near-complete mesh views; unioning all peers yields the same
set as the tree-only union in steady state (OR dedups overlap and no
filter can over-count) while damping the node-count flap on parent
switches, since dropping the parent no longer collapses the upward leg.
This also removes the estimate's dependence on tree-declaration cache
freshness.
Rename the debug-log child_count to contributor_count, adapt the two
membership-invariant tests to all-peers semantics, and add a test that
the estimate stays stable across a parent drop when a healthy cross-link
is present.
A node with a single tree peer has its periodic parent re-evaluation
disabled (it needs at least two peers for a meaningful comparison), so
it depends entirely on its peer pushing a TreeAnnounce for it to attach.
That push happens once at promotion time plus on the parent's slow
periodic no-change re-broadcast. If the one-shot attaching announce is
lost, the single-uplink node falls back to self-root and cannot recover
until the next periodic re-broadcast (reeval_interval_secs later),
stranding it out of the tree and unreachable end-to-end in the interim.
Make tree-position exchange self-healing on the receive path: when an
accepted TreeAnnounce advertises a root strictly worse (higher NodeAddr,
since election is smallest-wins) than our own, echo our current
declaration back to that peer. A stranded self-root node's announce now
provokes its better-rooted peer to re-push its real position immediately,
so the node re-attaches within a round-trip instead of waiting for the
periodic cadence.
Echo only in that one direction. If the peer's root is lower (better)
than ours, we are the stale side: the peer would ignore our worse root
anyway and we converge via the parent re-evaluation that follows, so
echoing back is pure waste and would double announce traffic in the
learning direction during a root change or partition merge. Equal roots
are already converged. The echo is bounded by the existing per-peer
500 ms tree-announce rate limiter and is a no-op once the peer adopts our
root, so it adds no traffic in a converged mesh.
Add a spanning-tree unit test that drives a converged child back to
self-root with its peer-ancestry view of the root cleared (modelling the
lost attaching announce), and asserts the root re-pushes on the
resulting root disagreement and the child re-attaches.
Brings the maint-line OR-union mesh-size estimator fix and the
per-peer / capacity-cap log-level demotions forward to master.
Conflict resolution: compute_mesh_size resolved to master's config()
accessor form carrying maint's OR-union rewrite (drop the stale summing
`total`); the log-level demotions auto-merged into master's handler
versions. The equivalent master-only log "connected UDP socket installed"
(connected_udp.rs, a file that does not exist on maint) was demoted
info -> debug as part of this merge so the connected-UDP path matches the
rest of the per-peer lifecycle logging.
On a saturated public-mesh node the connection-lifecycle and capacity-cap
events fire continuously and drown out the genuinely notable INFO/WARN
lines. Demote them to debug and drop a redundant duplicate:
- FMP K-bit cutover promotion (encrypted): info -> debug
- "Connection promoted to active peer" (handshake): info -> debug, and
remove the duplicate "Inbound peer promoted to active" line that
shadowed it on the inbound path
- "Peer restart detected" (handshake): info -> debug
- "Peer removed and state cleaned up" (dispatch): info -> debug
- "Rejecting inbound TCP connection (max_inbound_connections reached)"
(tcp): warn -> debug
- "Congestion detected, CE flag set on forwarded packet" (forwarding):
warn -> debug
- "Removing peer: link dead timeout" (mmp): warn -> debug
These are expected, high-frequency conditions on a busy public node (new
and reconnecting peers, ECN CE marking, the inbound connection cap, and
link-dead churn), not operator-actionable signals.
The mesh-size estimator summed the per-filter cardinality of the parent
filter and each child filter, which assumes those filters are perfectly
disjoint. When they overlap -- a stale or oversized parent filter, or a
routing loop -- the sum over-counts and inflates the reported mesh size
to as much as several times the true size.
Estimate the cardinality of the OR-union of the contributing filters
(self + parent + children) once instead. OR is idempotent, so any
overlap is deduplicated: the result equals the old sum in the disjoint
case and stays correct under overlap. The union is seeded from a clone
of a contributing filter so it keeps that filter's size class, and a
filter whose size class does not match is skipped rather than panicking.
The refuse-to-estimate behavior on a saturated or above-cap filter is
preserved.
Add a regression test with overlapping parent and child filters where
the naive sum over-counts and the union estimate tracks the distinct
member count.
Add a Loopback variant to TransportHandle backed by an unbounded
in-process channel and a shared address-to-receiver registry, so
node-level multi-node tests deliver packets directly between nodes
instead of over real localhost UDP sockets. This removes the kernel
UDP receive-buffer overflow that dropped handshake packets when many
tests ran in parallel under CPU contention, and lets the large-network
convergence tests run reliably in the default suite again (their
parallel-load ignore markers are removed).
The new transport and its enum variant are cfg(test)-gated, so the
daemon build is unaffected.
The FMP rekey msg1 resend driver retransmitted indefinitely with no cap
and no abandon, so a rekey that never completed kept resending msg1
forever. Give it a retransmission budget: cap resends at
handshake_max_resends with exponential backoff and abandon the rekey
cycle cleanly once the budget is exhausted, mirroring the FSP session
rekey msg3 driver.
With the cap in place the link-dead heartbeat can safely become
rekey-aware: check_link_heartbeats now suppresses teardown while a rekey
is in progress with msg1 budget remaining, instead of reaping a link
that is still actively carrying rekey-handshake traffic. The suppression
terminates deterministically (the budget abandons on exhaustion, cutover
clears the in-progress flag), so a genuinely dead link is still reaped on
the next cycle.
Adds a rekey_msg1_resend_count counter on ActivePeer reset at every
rekey-clear and cutover site, msg1 resend-budget unit tests, and two-node
heartbeat suppression/resume/regression integration tests.
Remove the duplicated immutable fields (config, identity, startup_epoch,
started_at, is_leaf_only, max_connections/peers/links) from the Node
struct so the Arc<NodeContext> bundle is the single source of truth.
Previously Node owned these fields and a parallel context copy, kept in
lockstep by rebuild_context() at every mutation site — pure overhead that
existed only because of the duplication.
- Replace rebuild_context() with replace_context(): a clone-edit-swap of
the whole Arc. The per-instance context stays immutable; mutation swaps
the Arc. This is the sole runtime mutation path (constructors, leaf_only,
update_peers).
- Add Copy-returning accessors startup_epoch() and max_connections()/
max_peers()/max_links(); migrate the remaining direct field readers onto
the accessors. node_addr()/npub()/Debug now read identity/is_leaf_only
from the context.
- update_peers reads the pre-update peer set from the live context Arc
before building a fresh Config + context and swapping — preserving the
read-before-write ordering its mutation-window test depends on.
- Remove the test-only set_max_* setters; tests set the limits on Config at
construction instead (new make_node_with_max_peers/links helpers).
- Add a ci-local guard that fails if the Node struct re-declares a bundled
field, so the single-store invariant can't silently regress.
cargo test --lib 1291/0; clippy -D warnings and release build clean.
Store node counters in an atomic metric registry read through &self, and
introduce a shared NodeContext bundle holding the effectively-immutable
fields (config, identity, startup epoch, capability limits). Source the
immutable config and identity reads across the receive hot path, the
handshake/session/mmp/encrypted state machines, and the discovery, tree,
bloom, retry, and lifecycle modules through the context accessors rather
than direct field reads. The Node fields and the context are rebuilt in
lockstep at every mutation site.
The discovery request dedup cache (recent_requests) silently dropped
LookupRequests once it reached MAX_RECENT_DISCOVERY_REQUESTS, with no
counter to surface the condition. Add a DiscoveryReject::ReqDedupCacheFull
reject reason backed by a req_dedup_cache_full counter on DiscoveryStats,
mirroring the existing duplicate-request counter, and record it at the
drop site so the rejection is visible in show_routing.
Bring the runtime peer-list refresh and opt-in mDNS LAN discovery work
on master into the receive-path RejectReason / reloadable-config
integration branch. Code files auto-merge clean; the only conflict is
the CHANGELOG Unreleased section, resolved as the union of both sets of
entries.
Add scoped mDNS / DNS-SD discovery for peers on the same local link,
giving sub-second pairing without a relay or NAT-traversal roundtrip.
A node advertises its npub, protocol version, and an optional network
scope over link-local multicast, and browses for matching adverts to
initiate Noise handshakes against same-LAN peers.
LAN discovery is disabled by default; operators enable it with
node.discovery.lan.enabled: true. Default-off avoids reintroducing a
per-LAN identity broadcast on nodes that have deliberately disabled
other discovery channels, and avoids any multicast surprise on upgrade.
The startup advertised-port picker now excludes bootstrap transports
and selects a non-bootstrap operational UDP transport with a stable
lowest-id selector, so the advertised port is deterministic across
restarts rather than dependent on HashMap iteration order. This
matches the per-dial transport selection used for discovered peers.
Co-authored-by: Johnathan Corgan <johnathan@corganlabs.com>
Add Node::update_peers for runtime peer-list refresh. It re-derives the
active peer connections from a new peer configuration, adding newly
configured peers and removing those no longer present, while keeping
links to peers that remain in the set rather than tearing every
connection down. The call returns an UpdatePeersOutcome summarizing the
added, removed, and retained peers.
PeerAddress gains a seen_at_ms recency field (with_seen_at_ms). Active
path selection now sorts address candidates by recency so the most
recently observed address wins when concurrent path probes race.
complete_rekey_msg2 now returns the remote peer's startup epoch
alongside the new Noise session, letting the rekey path detect a peer
restart and clear stale session state. A stale FSP session is cleared
when a peer restart is detected during FMP rekey or cross-connection
promotion, so the session-layer map no longer lingers out of sync with
the freshly promoted peer.
Per-tick work budgets bound the connection churn in a single node tick
(MAX_DISCOVERY_CONNECTS_PER_TICK, MAX_RETRY_CONNECTIONS_PER_TICK,
MAX_PARALLEL_PATH_CANDIDATES_PER_PEER); work beyond a tick's budget is
deferred to the next tick rather than discarded.
Co-authored-by: Johnathan Corgan <johnathan@corganlabs.com>
Move PeerAclReloader onto the Reloadable trait: its ACL snapshot is now
published through an arc_swap::ArcSwap so the authorization hot path reads
it without locking, and the former check_reload becomes the trait's
reload(). The node tick calls self.peer_acl.reload().await.
Wire the host map into the tick as well. The host map snapshot was
previously taken once at construction and never polled; it now hot-reloads
on /etc/fips/hosts mtime changes once per tick, alongside the ACL, so
hostname display reflects edits without a restart.
The path_mtu_lookup cache (event-driven, populated from observed traffic)
and the nostr_discovery subsystem (an async spawned task) are deliberately
left off the trait: neither reloads from a backing file, so a no-op reload()
would be misleading. The rationale is documented on the trait module.
The host map and the ACL's embedded alias reloader still stat /etc/fips/hosts
independently each tick. A single small-file stat per tick is cheap, so the
duplicate is left in place; sharing one mtime observation between the two is
a possible future cleanup.
Tests: a node-level test exercises the host-map tick reload end to end
through peer_display_name; the ACL reloader tests are updated to drive the
async reload().
Add a `Reloadable` trait that normalizes the node's reloadable
configuration/resource pattern onto a single contract built around an
`arc_swap::ArcSwap` snapshot: a lock-free `load()` for the hot read path
and an async `reload()` that re-reads the backing source and atomically
swaps in a fresh snapshot. The trait carries the canonical Arc-wrapper
template documentation (single-writer node tick, many-reader hot path,
whole-snapshot swap so readers never observe a partial update).
Migrate the host map to this trait via a new `HostMapReloadable` that
reuses the existing load/merge/mtime helpers in upper::hosts. The Node
`host_map` field changes from `Arc<HostMap>` to `HostMapReloadable`, and
`peer_display_name` reads through a lock-free guard. The initial snapshot
is byte-identical to the previous construction, so behavior is unchanged.
The host map is still snapshotted once at construction and not polled;
`reload()` is exercised only by unit tests for now. Wiring the periodic
poll into the node tick, and deduplicating the hosts-file stat against
the ACL reloader's embedded copy, is left as a follow-up.
Add `arc-swap` as a dependency. Unit tests cover initial load (base +
file, base only), change/no-change/deletion/creation detection,
base-preserved-on-reload, and equivalence of the initial snapshot to the
pre-migration construction.
Introduce a typed RejectReason enum and a NodeStats::record_reject
dispatch so every receive-path rejection-and-return site bumps a
machine-readable per-subsystem counter while keeping its operator-facing
log line. The top-level variants mirror the existing NodeStats subsystem
split (Tree, Bloom, Discovery, Forwarding) and add Handshake, Session,
Mmp, and Transport categories; HandshakeStats, SessionStats, and MmpStats
are new sub-stats.
Wired clusters: tree and MMP outbound sign-failure; the FSP session
unknown-session and state-machine cluster; the Noise IK handshake
state-machine cluster (msg1/msg2); and the decode / crypto / cap /
semantic tail across bloom, discovery, forwarding, mmp, and tree. The
TreeStats::ancestry_invalid counter, present since the scaffold but never
incremented, is now bumped from the validate_semantics ancestry rejection.
Several handshake, MMP, tree, and discovery paths that previously had no
counter at all are now counted, including the send_lookup_response
no-route drop (DiscoveryStats::resp_no_route).
Existing direct counters at the bloom / discovery / forwarding sites are
retained alongside the new dispatch while the rollout is in progress (the
bloom_poison tests expect the transitional +2 delta); a later change
collapses the duplicate increment.
Raise the in-process backpressure headroom in make_test_node_with_mtu
(request an 8 MiB recv_buf_size on UdpConfig and grow packet_channel from
256 to 8192) to reduce localhost-UDP receive overflow under parallel-CPU
scheduler contention, and mark the large-network convergence tests
#[ignore] so cargo test --lib stays green by default. The ignored tests
remain runnable on demand with --ignored or --test-threads=1.
Move the max_peers cap check in handle_msg1 forward, from the late
check inside promote_connection (which fires after Msg2 has already
been built and put on the wire) to an early position after identity
verification but before index allocation and the Msg2 send. When the
gate fires for a net-new identity, the Msg1 is silent-dropped — no
response goes back to the peer, no AEAD compute or wire bytes are
spent.
Bypass preserved for known peers (reconnect / cross-connection): if
the sender's NodeAddr is already in self.peers, or if a pending
outbound connection is in flight to the same identity, the gate is
skipped so legitimate maintenance traffic continues to work. The
late check inside promote_connection is intentionally retained as
defense-in-depth against future call sites or a disconnect racing
between the early-gate decision and promotion.
Wire-cost rationale: a 45 s tcpdump at saturation observed ~3.6
cap-denials/s steady-state, each previously paying the full Noise IK
responder crypto + Msg2 (~104 B) on the wire before being rejected.
The bigger value is cleaner peer-side semantics — the peer no longer
sees a fake-completed handshake whose data frames subsequently fail
decryption locally.
Two new unit tests cover the cases:
- handle_msg1_silent_drops_at_cap_for_new_peer drives a wire-pumped
Msg1 from a fresh identity into a saturated node and asserts no
Msg2 reaches the sender socket. Stash-verifies as FAIL on the
pre-fix tree (Msg2 hits the wire) and PASS post-fix.
- handle_msg1_admits_existing_peer_at_cap drives a Msg1 from an
identity already in self.peers and asserts the gate does not evict
it. This is a regression check (the no-gate tree behaves the same
way here, but the test guards against an accidental future gate
that breaks known-peer admit).
Brings two structural fixes landed on maint:
- compute_mesh_size: explicit parent skip in the children loop, so the
disjoint-subtree invariant no longer depends on peer_declaration cache
freshness.
- max_peers: outbound connection-initiation gated on the cap (auto-reconnect
retries, Nostr-mediated discovery established adoption, and both sides
of the NAT-traversal punch sequence). Inbound msg1 admission gate
unchanged.
node.limits.max_peers was honored only on inbound msg1 admission
(handshake.rs handle_msg1 returns PeerLimitExceeded when peers.len
is at the cap). Four outbound initiation paths proceeded unconditionally
at capacity: auto-reconnect retries (process_pending_retries),
Nostr-mediated discovery's BootstrapEvent::Established adoption
(poll_nostr_discovery), NAT-traversal punch initiation (the outgoing
side of the offer/answer/punch sequence in the Nostr discovery
runtime), and NAT-traversal punch response (the incoming side of the
same sequence). A saturated node burned CPU, UDP probes, STUN
observations, and Nostr relay traffic on connections that the inbound
gate would reject the moment they reached msg1.
Introduce Node::outbound_admission_check (peers.len < max_peers, or
true when max_peers == 0 as the no-cap sentinel) and gate the four
paths. The discovery runtime lives in a separate task and does not
hold a Node reference; bridge via an Arc<AtomicBool> the runtime
reads and Node refreshes once per tick from outbound_admission_check.
The atomic granularity is intentionally loose: one-tick lag is
acceptable because the inbound msg1 gate continues to be the
authoritative cap, and in-flight handshakes started below the cap
are allowed to complete.
Inbound gate at handshake.rs is unchanged.
The mesh-size estimator's children loop relied on the cached
peer_declaration(parent_id).parent_id() != my_addr check to exclude
the parent. That cached view briefly disagrees with our own latest
my_declaration().parent_id() during the window between a local
parent-switch and the new parent's next inbound TreeAnnounce: the
peer-declaration cache still names us as the parent's parent, so the
parent is iterated as if it were a child and its (typically dominant)
bloom cardinality is added a second time. Symptom: estimated mesh size
displayed in fipsctl show status and fipstop nearly-but-not-exactly
doubles during tree rebalancing.
Make the invariant structural with an explicit peer_addr == parent_id
skip at the head of the children loop. Per-peer 500 ms rate-limiter
and overall recompute cadence are unchanged.
Adds a regression test that constructs the stale-peer-declaration
scenario directly and asserts the parent is not double-counted.
Closes the eventually-consistent gap in spanning-tree state
distribution. Every existing send_tree_announce_to_all call site
gates on a local state-change event (parent switch, self-root
promotion, ancestry change, peer promotion, parent loss). Once a
partition latches — for example a parent-switch announce stranded
in the brief cross-init handshake swap window, where the announce
arrives on a session-index whose decrypt-worker entry has been
unregistered — neither side's state changes again, so neither
side ever re-broadcasts. The existing 60 s check_periodic_parent_reeval
was a re-evaluation, not a re-broadcast: it short-circuited
silently on no-change. Production-side healing depended on
incidental link churn; lab harnesses with stable docker-bridge
links had no equivalent path.
Add a final else branch that fires send_tree_announce_to_all
unconditionally on the no-change path, alongside the existing
switch and self-promote arms. Receivers coalesce by sequence
comparison (ParentDeclaration::is_fresher_than) and short-circuit
at the `if !updated` gate in handle_tree_announce; same-sequence
repeats drop silently with no cascade. The per-peer 500 ms
rate-limiter is well below this 60 s cadence and does not suppress
the heartbeat broadcast.
The fix is a general protocol-robustness improvement: it addresses
any in-flight TreeAnnounce loss class, not only the specific
cross-init swap-window drop site.
testing/static/scripts/rekey-test.sh BASELINE_CONVERGENCE_TIMEOUT
60 -> 65 so a partition healed by the periodic broadcast at T+60
lands inside the convergence window. wait_for_full_baseline
early-exits on PASS, so successful reps see no extra wall-clock.
The cross-connection-won path in handle_msg1 removes the old peer and frees
its allocated index, but does not unregister the old (transport_id, our_index)
cache_key from the decrypt worker pool. The orphan entry sits in the
per-shard HashMap until the index allocator recycles old_idx to a different
peer and that peer's register_decrypt_worker_session call overwrites it.
In the interim, any decrypt job that lands at the recycled cache_key
resolves to the wrong session and AEAD silently fails — observed as
multi-hop routing failure in 5-node static-mesh on next-branch where
bidirectional auto_connect drives cross-connections at every peer pair
on startup.
The tick body's per-peer check_* loops (heartbeats, bloom
announces, MMP reports, tree announces) called transport.send
for every active peer, which on TCP/Tor fell through to a 5 s
connect-on-send wait for any peer whose pool entry was not yet
established. That wedged the entire tick body for the full
connect_timeout_ms per unreachable peer; under post-restart
convergence on a high-peer mesh, this cascaded into multi-
second tick stalls. On master, the same mechanism also starved
the per-tick control-snapshot republish and pushed fipsctl
queries onto an mpsc fallback that was itself queued behind
the wedged rx_loop, producing the 5-second fipsctl head-of-line
pattern operators observed on loaded nodes.
Gate send_encrypted_link_message_with_ce on
transport.connection_state before the send: proceed only when
Connected; on None, kick off a non-blocking background connect
(idempotent — TransportHandle::connect dedupes against the
connecting pool and spawns the timeout-bounded TcpStream::connect
inside its own tokio task) and fail this send fast with a
clear "transport connection not ready" error. A subsequent
tick retries once the pool has an entry. The reconnect
lifecycle (check_link_heartbeats, process_pending_retries,
poll_pending_connects) is unchanged. The connect-on-send
branch in transport.send_async itself remains in place for
code paths that legitimately need synchronous connect (e.g.,
explicit operator-driven fipsctl connect).
When both peers' Nostr-mediated UDP punches complete within the
same scheduling window, each side's `BootstrapEvent::Established`
event arrives with `is_connecting_to_peer` already true: each side
received an inbound msg1 from the peer's pre-punch outbound
attempt, which created a connecting-state record. The deduplication
skip then fires on both sides, neither installs the fresh
traversal socket as canonical, and the peer-adoption budget
(45 s) expires. Cross-node wall-clock alignment of the skip log
line in observed failures was within ~1 ms — simultaneous dual-
fire under contention, the dual-initiation pattern.
Apply the deterministic NodeAddr tie-breaker already used at
`handlers/handshake.rs:269` for rekey dual-initiation and in
`peer::cross_connection_winner` for cross-connection resolution.
Smaller NodeAddr wins as adopter: enumerate the in-flight
connections whose `expected_identity` points at this peer, tear
them down via the canonical `cleanup_stale_connection` helper, and
fall through to `adopt_established_traversal`. Larger NodeAddr
loses and keeps the existing `continue` semantics; the loser's
in-flight outbound is reconciled by `handle_msg1`'s cross-
connection logic when the winner's fresh msg1 arrives over the
adopted socket.
`cleanup_stale_connection` visibility bumped from module-private
to `pub(in crate::node)` so it is callable from `lifecycle.rs`.
The defensive re-check inside `adopt_established_traversal`
itself is left as-is — after the outer cleanup the winner reaches
it with `is_connecting_to_peer == false`, so the inner skip
won't trip. The `BootstrapEvent::Failed` arm is unchanged: there
is no winning outcome on dual failure, and the existing skip +
retry-schedule semantics are correct.
The cross-connection-won branch of `promote_connection` builds a
fresh ActivePeer with a new Noise session and our_index, inserts
it into peers, and registers identity, but did not hand the new
session to the decrypt shard worker pool. The normal-promotion
tail in the same function does make that call. A session
established via the cross-connection race path therefore missed
the worker fast-path for its lifetime, falling back to inline
decryption on the rx loop. Correctness was unaffected, but the
throughput/latency benefit of the worker pool was lost for peerspromoted through that path.
Mirror the normal-promotion tail and call
`register_decrypt_worker_session` after the fresh ActivePeer is
inserted into `self.peers` in the `this_wins` arm.
Logs source, destination, and payload size at the existing no-route
drop site so investigations can attribute transit drops without
enabling trace-level instrumentation. Diagnostic-only; no behavior
change on the success path.
An FSP session rekey could leave the two endpoints holding different
key sets for a brief window: if a handshake message was lost in
transit, one side rotated to the new keys while the other did not.
Traffic sealed in one key epoch then reached a peer still on the
other epoch and failed to decrypt, producing bursts of AEAD
decryption failures and dropped connectivity until a later rekey
cycle reconverged the pair. Choreographing the cutover order cannot
close this window: any fixed ordering still leaves a skew that
packet reordering widens.
Make rekey correctness independent of cutover timing by overlapping
the key epochs on the receive path. During a rekey transition the
receiver trial-decrypts each frame against every live session it
holds: current, the not-yet-promoted pending session, and the
draining previous session. The K-bit becomes a hint that orders the
trial-decrypt cascade rather than a hard gate, and a frame that
authenticates against the pending session is itself the cutover
signal. No rotation ordering and no packet reordering can then cause
a decryption failure.
The pre-rekey Noise session is held in the `previous` slot until the
peer has demonstrably moved off it. Its drain deadline is anchored
on the most recent frame the peer authenticated against that slot,
refreshed each time the trial-decrypt cascade lands there, rather
than on a fixed wall-clock timer started unilaterally at the local
cutover. A peer that never received the new keys keeps authenticating
against `previous` and the slot stays live; without this, a fixed
timer would erase the only key set that could decrypt the peer's
frames, producing a permanent silent decrypt failure on a live data
path. A peer that never catches up is handled by the existing FSP
session liveness path rather than by silent decrypt failure.
The lost-handshake liveness gap is closed separately by retransmitting
the third rekey handshake message until the peer is confirmed on the
new keys, with a bounded retry budget after which the rekey cycle is
cleanly abandoned and retried on the next timer.
Adds unit tests covering the trial-decrypt cascade (epoch selection,
promotion on pending decrypt, reordered old-epoch stragglers after
cutover, per-slot replay-window integrity), the msg3 retransmission
lifecycle, and the peer-progress-aware drain retirement.
Moves both AEAD layers (ChaCha20-Poly1305, one round per layer per
packet) plus the sendmsg syscall off the rx_loop task onto a per-shard
worker pool, adds per-peer connect(2)-ed UDP with SO_REUSEPORT, and
uses Linux UDP GSO (sendmsg+UDP_SEGMENT — kernel splits one super-skb
into N on-the-wire datagrams in a single TX-stack walk) when packets
in a batch are uniform-size. Same kernel primitive WireGuard's
in-kernel module and BoringTun use to hit 2.5–3.2 Gbps single-stream.
Single TCP stream on a 5-node docker-bridge mesh, 5 x 15 s x P=1:
A→D: 1379 → 2708 Mbps (1.96x, RTT +0.12 ms)
A→E: 1394 → 2663 Mbps (1.91x, RTT +0.11 ms)
E→A: 1406 → 2624 Mbps (1.87x, RTT +0.19 ms)
Static-peer pairs only — every CoV under 3%, 0 outliers, 0% ICMP
loss. The ~+100 µs RTT is the worker queue handoff cost; AEAD +
sendmmsg now run on a separate core in exchange.
What lands:
- src/node/encrypt_worker.rs: std::thread + crossbeam_channel
workers; hash-by-destination dispatch pins a TCP flow to one
worker so wire ordering is preserved; per-worker sendmmsg(2)
batching up to 32; Linux uses sendmsg(2)+UDP_SEGMENT when
packets in a group are uniform-size.
- src/node/decrypt_worker.rs: receive-side mirror. Each shard owns
its session's recv cipher + replay window in a thread-local
HashMap (no shared RwLock/Mutex). Sessions are handed off at
promote_connection and re-registered on K-bit flip / rekey
cutover.
- src/node/handlers/session.rs try_send_session_data_pipelined:
FSP+FMP both seal in-place in the worker on one wire-buffer
alloc; no intermediate inner_plaintext / fsp_payload Vecs.
- src/transport/udp/connected_peer.rs + peer_drain.rs: per-peer
connect(2)-ed UDP socket with SO_REUSEPORT (set on the listen
socket too — without that, EADDRINUSE on activation and every
packet falls back to the wildcard path); the worker sends with
msg_name=NULL and the kernel uses its cached 5-tuple. Tick-
driven activation in handlers/connected_udp.rs, idempotent.
- src/transport/udp/mod.rs: mem::replace the recvmmsg backing buffer
instead of buf.to_vec() per packet — single pointer swap, no
MTU-sized memcpy.
- src/protocol/link.rs SessionDatagramRef: zero-copy borrowed view
used by handle_session_datagram for the bulk local-delivery
path; handle_session_payload takes the borrowed payload
directly (no payload[35..].to_vec()).
- src/transport/mod.rs TransportAddr::from_socket_addr: collapses
the two-alloc from_string(addr.to_string()) pattern to one.
- src/node/handlers/rx_loop.rs: decrypt-fallback drain promoted
ahead of packet_rx in the select! (TCP ACK starvation fix);
interleaved fallback drain every 32 packets inside the rx burst
loop.
- noise::Session: send_cipher_clone / recv_cipher_clone /
recv_replay_snapshot_owned / take_send_counter / accept_replay
so off-task workers can hold a cloned cipher + reserved counter
while the dispatcher keeps replay/counter sequencing serial.
CipherState::cipher_clone returns a refcount-bumped LessSafeKey.
AsyncUdpSocket: AsRawFd so workers issue raw sendmmsg / sendmsg
without going through the tokio reactor.
- Worker pool sizing: both default to num_cpus, overridable via
FIPS_ENCRYPT_WORKERS=N / FIPS_DECRYPT_WORKERS=N. Per-peer
connected UDP can be disabled via FIPS_CONNECTED_UDP=0.
- src/perf_profile.rs: optional per-stage timing reporter under
FIPS_PERF=1 (or FIPS_PIPELINE_TRACE=1). Off by default; zero
overhead when disabled.
- All cfg(unix)-gated. Windows continues on the existing tokio-
based send/recv.
Decrypt worker session lifecycle:
- Node::unregister_decrypt_worker_session mirrors the existing
register helper. Wired at the two natural sites that already
iterate peers_by_index: the rekey drain-completion block in
handlers/rekey.rs (drops the worker entry for the old our_index
once the drain window has expired and the cache_key is
unreachable to any in-flight OLD-K packet), and remove_active_peer
in handlers/dispatch.rs (drops the worker entry for each of the
four index slots: current, rekey, pending, previous). Only
our_index is normally registered; unregister_session is fire-
and-forget for missing entries, so calling unconditionally on
all four slots is correct and bounds the cleanup without per-
slot accounting. Without these callers the per-worker sessions
HashMap and the Node's decrypt_registered_sessions set would
grow monotonically per rekey on long-lived peers.
Testing:
- testing/static/scripts/bench-multirun.sh: multi-run iperf3 +
ping bench. N reruns (default 5), median / min / max / CoV % /
per-run outlier flag, avg ping RTT, ICMP loss %, TCP retransmit
total. Plain client→dest labels + topology header. Pre-bench
peer-convergence check (FIPS_BENCH_CONVERGE_SECS, default 15);
per-path route verification via stats.bytes_sent deltas — fails
fast if traffic exits via a non-static-peer link.
- testing/static/docker-compose.yml: passes FIPS_ENCRYPT_WORKERS /
FIPS_DECRYPT_WORKERS / FIPS_PERF through to containers for A/B
benchmarking without rebuilds.
- testing/static/scripts/iperf-test.sh: same plain client→dest
labels + topology header (was multihop/direct/N hop, which
conflated topology distance with on-wire path).
- .config/nextest.toml: synthetic UDP node tests serialized
through a max-threads=1 test group. Localhost handshakes drop
on shared CI runners under parallel load; one-at-a-time keeps
assertions reliable.
- src/node/tests/spanning_tree.rs: repair_missing_edge_handshakes
— retries up to 5 times for synthetic edges whose msg1 was
dropped, with a drain after each edge retry instead of after
each attempt's full burst.
- src/node/decrypt_worker.rs::tests: two unit tests asserting
WorkerMsg::UnregisterSession removes the worker-thread session
HashMap entry (handle_msg_unregister_session_removes_entry) and
is a no-op for never-seen cache_keys
(handle_msg_unregister_session_idempotent_on_unknown_key), which
is the safety invariant the unconditional unregister calls at
the four index slots in remove_active_peer rely on.
- src/node/encrypt_worker.rs::unix_tests
pipelined_send_wire_layout_roundtrips_canonical_decoders: mirrors
the encoder geometry of try_send_session_data_pipelined (no
coords, the common established-session path), runs the worker's
real seal + send via flush_direct_batch_sync, and decodes the
resulting wire packet using only canonical receive-side decoders
(EncryptedHeader::parse, SessionDatagramRef::decode, FSP header
parse, noise::open). Any divergence between the hand-rolled
encoder offsets (fsp_aad_offset, fsp_plaintext_offset) and the
decoders fails at one of the parse / open / decode steps before
the inner-plaintext assertion fires. Complements the existing
fsp_preseal_runs_before_outer_fmp_seal test which covers the
seal-ordering invariant with synthetic headers but does not
exercise the wire-layout invariant.
CHANGELOG.md [Unreleased] # Changed entry added describing the
worker-pool threading model, hash-by-destination dispatch,
sendmmsg/UDP_GSO, per-peer connected UDP, the operator-facing env
vars, and the bench numbers above.
Cherry-picks from mmalmi/master (paths translated from
crates/fips-core/src/ to src/): 9b7c723, 0deb5cb, 13f7339, e036c0e,
3740a68, 3792f83, 8510193, 4910b07, e53f545, e4e2896, 5fe4af5,
1d01ada, 8c37008, e12469e, 6eb2860.
Co-authored-by: Johnathan Corgan <johnathan@corganlabs.com>
Replaces the unconditional `CoordCache::clear()` calls at parent-switch,
become-root, and loop-detection sites with two targeted invalidation
methods scoped to what actually makes an entry stale:
- `invalidate_via_node(node_addr)`: drop entries whose cached
destination ancestry contains `node_addr`. Used at parent-position-
change sites — our prefix changed, so destinations downstream of
us have stale-prefix coords.
- `invalidate_other_roots(current_root)`: drop entries rooted under
a different root than the current one. Used at root-change sites.
Under the previous global flush, parent switches blanked the cache
across the board, leaving `find_next_hop` returning `None` for every
non-direct-peer destination until the cache passively re-warmed via
incoming TreeAnnounces / SessionSetup. Surgical invalidation
preserves entries that remain correct after the topology change.
The cached coord describes a destination's tree position; that
position only goes stale relative to our own routing decisions when
our own prefix changes (entries we are downstream of) or the root
changes (entries in a different tree). Peer removal does not
invalidate cached coords: `Node::find_next_hop` recomputes the
next-hop decision on every call against the current peer set, bloom
filters, and tree state, and Discovery already triggers on
`no route to destination` errors when a destination becomes
unroutable through us. The peer-removal site retains the original
"no cache invalidation" behavior.
Each method returns the count of entries removed for observability.
Unit tests cover each method against the cases enumerated in the
acceptance criterion.
- Borrowed SessionDatagramRef decoder is used in the forwarding
handler so local delivery and coordinate-cache warming no longer
allocate or copy the session payload. The owned SessionDatagram is
materialized only when re-encoding for the next hop.
- Owned SessionDatagram::decode is reimplemented as Ref::decode +
into_owned, so the two decoders cannot drift.
- recvmmsg / recvmsg_x (Linux + macOS) receive loop moves each filled
slot buffer into ReceivedPacket via mem::replace instead of cloning
it; a fresh empty buffer is installed for the next syscall.
- TransportAddr is formatted directly from the SocketAddr without
going through an intermediate String.
Focused decode bench: ref 1.6 ns/op vs owned 34.7 ns/op (21.4x).
End-to-end iperf is neutral as expected for a ~30 ns saving per
packet.
Unit tests added:
- test_session_datagram_ref_decode_borrows_payload (verifies the
payload slice pointer equals the input slice's offset 35, a real
zero-copy invariant guard against accidental future to_vec)
- bench_session_datagram_decode_owned_vs_ref (ignored, run with
--ignored --nocapture)
- test_transport_addr_from_socket_addr
Skip BootstrapEvent::Established and BootstrapEvent::Failed dispatch
in poll_nostr_discovery for peers that are already connected or
actively handshaking. Without these guards, stale traversal events
arriving after a peer connected through a different path would
either attempt to adopt a redundant socket against the live
connection (Established) or poison the per-peer failure-state
cooldown and trigger redundant retraversal via schedule_retry /
try_peer_addresses (Failed).
The four guard sites use a new is_connecting_to_peer helper extracted
from the existing closure inside initiate_peer_connection; the helper
checks for an in-flight outbound handshake state. adopt_established_traversal
gains a defense-in-depth check returning PeerAlreadyExists when called
against an already-promoted peer, so the invariant holds if a future
caller bypasses the outer dispatch guard.
Side benefit: narrows a cooldown-poisoning vector previously available
to an attacker injecting stale failure events for an active peer.
Test coverage for the new behavior:
- test_try_peer_addresses_skips_connected_peer
- test_try_peer_addresses_skips_connecting_peer
- test_nostr_traversal_failure_skips_connected_peer (Failed-arm event
injection)
- test_nostr_traversal_established_skips_connected_peer (Established-arm
event injection, mirror of the Failed test)
- test_adopted_traversal_skips_already_connected_peer
(adopt_established_traversal defense-in-depth)
CHANGELOG entry under [Unreleased] / Fixed.
Closes#87
Add a per-session signed jitter offset (uniform [-15, +15] seconds)
to the rekey timer triggers in check_rekey (FMP) and check_session_rekey
(FSP). The configured `node.rekey.after_secs` becomes the nominal
interval rather than a floor; mean is preserved. Desynchronizes
both endpoints in symmetric-start meshes so the dual-initiation
race stops occurring rather than being resolved after the fact by
the smaller-NodeAddr tie-breaker.
Per-session storage means each rekey cutover reconstructs the
session and redraws the jitter naturally — successive cycles get
independent offsets, preventing drift back into sync.
Johnathan Corgan
Martti MalmiandJohnathan Corgan