- Extract refresh_entry in ctx.rs — warm_domain in main.rs now delegates
to it instead of duplicating the resolve+cache logic (~40 lines removed)
- Eliminate unconditional .to_vec() of raw wire on every UDP/DoT query —
pass &buffer.buf[..len] directly (zero-cost for cache hits)
- Replace bare bool stale flag with Freshness enum (Fresh/NearExpiry/Stale)
making the three states self-documenting at every call site
Entries with <10% TTL remaining are now marked stale on lookup,
triggering a background refresh before they expire. Combined with
the serve-stale + background refresh from the previous commit, this
means entries are proactively refreshed — matching Unbound's prefetch
behavior.
The 10K cap was too conservative — the blocklist alone holds 400K domains.
At ~100 bytes per wire entry, 100K entries is ~10MB.
When the cache is full and evict_expired doesn't free enough slots,
evict_stalest removes the entry with the least remaining TTL instead of
silently discarding the new insert.
Wire-level forwarding path skips DnsPacket parse/serialize on the hot
path. Cache stores raw wire bytes with pre-scanned TTL offsets — patches
ID + TTLs in-place on lookup instead of cloning parsed packets.
Request hedging (Dean & Barroso "Tail at Scale") fires a second
parallel request after a configurable delay (default 10ms) when
the primary upstream stalls. DoH keepalive loop prevents idle
HTTP/2 + TLS connection teardown.
Recursive resolver now hedges across multiple NS addresses and
caches NS delegation records to skip TLD re-queries.
Integration test harness polls /blocking/stats instead of fixed
sleep, eliminating the blocklist-download race condition.
