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Johnathan Corgan
bcc9c525d3
Public-test daemons with populous open-discovery caches generate
sustained NAT-traversal-failure WARN volume (~140/hour, ~3500/day)
against cache-learned peers that have gone offline — their adverts
are absent from major Nostr relays but cached entries persist until
their advertised `valid_until` expires. The daemon kept publishing
offers indefinitely under exponential backoff with no per-peer
suppression, drowning operator signal and hammering relays. A
parallel concern: the strict freshness check at signal.rs silently
rejected offers under modest clock skew (now_ms() anchors to
SystemTime once at startup, so post-startup NTP step adjustments
don't propagate on long-uptime daemons), indistinguishable from
"peer is offline."
Six independent improvements layered on the existing retry logic.
Per-npub WARN log rate-limit
----------------------------
New `FailureState` struct on `NostrDiscovery` records per-npub
`last_warn_at_ms`. Subsequent failures inside `warn_log_interval_secs`
(default 5 min) emit DEBUG instead of WARN. Each WARN now also
carries `consecutive_failures` and remaining `cooldown_secs` so
operators can read the trajectory without grepping multiple lines.
Per-npub consecutive-failure counter + extended cooldown
--------------------------------------------------------
After `failure_streak_threshold` (default 5) consecutive failures
against a peer, the next `extended_cooldown_secs` (default 1800)
of attempts are suppressed by pushing
`retry_pending[npub].retry_after_ms` past the cooldown wall. The
open-discovery sweep also consults `cooldown_until` and increments
a new `skipped_cooldown` counter so a peer whose `retry_pending`
was cleared by max_retries doesn't get re-enqueued during the
cooldown window. Caps offer-publish rate per dead peer regardless
of how often the sweep tries to re-enqueue.
Stale-advert eviction on streak-threshold transition
----------------------------------------------------
On the threshold-crossing transition (one-shot, not every
subsequent failure), `tokio::spawn` an active re-fetch of the
peer's Kind 37195 advert from `advert_relays`. Three outcomes:
- absent on relays → cache evicted; sweep won't re-enqueue
(peer is genuinely gone).
- newer `created_at` → cache refreshed + streak reset
(peer republished; allowed to retry immediately).
- same → cache untouched; cooldown stands.
Cost: ~one fetch per dead peer per 30-min cooldown cycle, vs
hundreds of offer publishes/hour today.
Clock-skew tolerance on freshness check
---------------------------------------
`signal.rs` `validate_offer_freshness` and
`validate_traversal_answer_for_offer` now allow ±60s grace beyond
strict TTL. Both return a new `FreshnessOutcome` enum so callers
can DEBUG-log when an offer/answer was only accepted via the grace
window. `FRESHNESS_SKEW_TOLERANCE_MS` is hard-coded — loosening
this past minutes erodes the freshness/replay security boundary
and operators tend to tune in the wrong direction.
NTP-style skew estimate (offer_received_at echo)
------------------------------------------------
Added optional `offerReceivedAt: Option<u64>` field to
`TraversalAnswer` payload. Responder fills it with `now_ms()` at
offer-receipt time. Initiator computes the standard NTP offset
formula `((T2-T1) + (T3-T4)) / 2` against the round-trip and
DEBUG-logs when `|skew| ≥ 30s`. Skew is also stashed in
`FailureState` and surfaced in `show_peers`. Non-breaking — older
responders that don't fill the field still produce valid answers,
and `estimate_clock_skew` returns `None`.
Per-peer state in `show_peers` JSON
-----------------------------------
Each peer entry in `show_peers` now carries:
"nostr_traversal": {
"consecutive_failures": <u32>,
"in_cooldown": <bool>,
"cooldown_until_ms": <u64 | null>,
"last_observed_skew_ms": <i64 | null>
}
Always emitted (schema-stable); values populated when discovery is
enabled and the npub has a recorded entry. Required a new public
`Node::nostr_discovery_handle()` accessor and refactored
`FailureState`'s internal Mutex from `tokio::sync` to `std::sync`
(operations never hold across await), which lets the synchronous
`show_peers` handler call `snapshot()` directly without the
dispatcher becoming async.
New config knobs (under `node.discovery.nostr`)
-----------------------------------------------
failure_streak_threshold: 5
extended_cooldown_secs: 1800
warn_log_interval_secs: 300
failure_state_max_entries: 4096
Tests
-----
12 new unit tests:
- 5 in `tests.rs` covering freshness strict / tolerated / rejected
outcomes, NTP skew estimation, and the backward-compat None case
when the responder didn't fill `offer_received_at`.
- 7 in `failure_state.rs` covering streak/warn-rate-limit state
transitions, cooldown active vs expired semantics,
success-resets-streak, observed-skew records, and size-cap
eviction by oldest `last_failure_at`.
CHANGELOG entries added under `[Unreleased]` Fixed.