* feat: in-flight query coalescing for recursive resolver
When multiple queries for the same (domain, qtype) arrive concurrently
and all miss the cache, only the first triggers recursive resolution.
Subsequent queries wait on a broadcast channel for the result.
Prevents thundering herd where N concurrent cache misses each
independently walk the full NS chain, compounding timeouts.
Uses InflightGuard (Drop impl) to guarantee map cleanup on
panic/cancellation — prevents permanent SERVFAIL poisoning.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
* style: add InflightMap type alias for clippy
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
* feat: add COALESCED query path and coalescing tests
Followers in the inflight coalescing path now log as COALESCED instead
of RECURSIVE, making it visible in the dashboard when queries were
deduplicated vs independently resolved. Adds 10 tests covering
InflightGuard cleanup, broadcast mechanics, and concurrent handle_query
coalescing through a mock TCP DNS server.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
* style: cargo fmt
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
* refactor: extract acquire_inflight, rewrite tests against real code
Move Disposition enum and inflight acquisition logic into a standalone
acquire_inflight() function. Rewrite 4 tests that were exercising tokio
primitives to call the real coalescing code path instead.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
* feat: SRTT-based nameserver selection for recursive resolver
BIND-style Smoothed RTT (EWMA) tracking per NS IP address. The resolver
learns which nameservers respond fastest and prefers them, eliminating
cascading timeouts from slow/unreachable IPv6 servers.
- New src/srtt.rs: SrttCache with record_rtt, record_failure, sort_by_rtt
- EWMA formula: new = (old * 7 + sample) / 8, 5s failure penalty, 5min decay
- TCP penalty (+100ms) lets SRTT naturally deprioritize IPv6-over-TCP
- Enabled flag embedded in SrttCache (no-op when disabled)
- Batch eviction (64 entries) for O(1) amortized writes at capacity
- Configurable via [upstream] srtt = true/false (default: true)
- Benchmark script: scripts/benchmark.sh (full, cold, warm, compare-all)
- Benchmarks show 12x avg improvement, 0% queries >1s (was 58%)
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
* feat: show DNSSEC and SRTT status in dashboard + API
Add dnssec and srtt boolean fields to /stats API response.
Display on/off indicators in the dashboard footer.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
* fix: apply SRTT decay before EWMA so recovered servers rehabilitate
Without decay-before-EWMA, a server penalized at 5000ms stayed near
that value even after recovery — the stale raw penalty was used as the
EWMA base instead of the decayed estimate. Extract decayed_srtt()
helper and call it in record_rtt() before the smoothing step.
Also restores removed "why" comments in send_query / resolve_recursive.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
* docs: add install/upgrade instructions, smarter benchmark priming
README: document `numa install`, `numa service`, Homebrew upgrade,
and `make deploy` workflows. Benchmark: replace fixed `sleep 4` with
`wait_for_priming` that polls cache entry count for stability.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
