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resolveIdentity runs on every register (block + flap gates). It already returned on device_id before any DB access; memoized the device_fingerprints statement (prepared once, lazily) and documented the invariant. Test asserts a device_id-present resolve prepares/runs ZERO device_fingerprints queries; a device_id-absent resolve does. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
59 lines
2.5 KiB
JavaScript
59 lines
2.5 KiB
JavaScript
'use strict';
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// #146 hardening — SNAT-safe identity resolution for any per-device keying (flap
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// limiter, operator block, throttles). The whole fleet egresses as ONE IP
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// (10.10.10.1, Sophos SNAT), so keying on IP collapses the fleet into one bucket —
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// FORBIDDEN. Resolve identity from the device:register payload via the fallback chain:
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//
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// device_id
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// -> fingerprint (map via device_fingerprints -> device_id when it resolves,
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// else the raw fingerprint string)
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// -> device_token
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// -> a single BOUNDED GLOBAL anon bucket (final backstop)
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//
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// An unidentifiable client is STILL bucketed (collectively, via the anon bucket) so an
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// anonymous flood is capped, never unthrottled. Mirrors lib/ota-breaker's
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// device_id-or-version fallback. `fingerprint` is present in the register payload;
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// device_fingerprints maps fingerprint -> device_id. NEVER keys on IP.
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const { db } = require('../db/database');
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const ANON_KEY = 'anon:global';
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// Memoized statement — prepared once, lazily (safe on a partially-migrated DB).
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let _fpStmt = null;
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function fpStmt() {
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if (!_fpStmt) { try { _fpStmt = db.prepare('SELECT device_id FROM device_fingerprints WHERE fingerprint = ?'); } catch (_) { return null; } }
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return _fpStmt;
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}
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// Returns { key, kind, deviceId } — `key` is stable for keying; `deviceId` is the
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// resolved device id when the chain produced one (device_id directly or via
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// fingerprint), else null.
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//
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// #146 P1: SHORT-CIRCUITS on device_id — the common case (a device that sends its
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// device_id) returns immediately with ZERO DB lookups. The device_fingerprints SELECT
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// runs ONLY when device_id is absent. Called on every register (block + flap gates), so
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// the hot path must stay lookup-free.
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function resolveIdentity(payload = {}) {
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const { device_id, fingerprint, device_token } = payload;
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if (device_id) return { key: 'd:' + device_id, kind: 'device_id', deviceId: device_id };
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if (fingerprint) {
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let mapped = null;
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try {
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const st = fpStmt();
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const row = st && st.get(fingerprint);
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mapped = row && row.device_id ? row.device_id : null;
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} catch (_) { /* table may not exist on a partially-migrated DB */ }
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if (mapped) return { key: 'd:' + mapped, kind: 'fingerprint->device_id', deviceId: mapped };
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return { key: 'f:' + fingerprint, kind: 'fingerprint', deviceId: null };
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}
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if (device_token) return { key: 't:' + device_token, kind: 'device_token', deviceId: null };
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return { key: ANON_KEY, kind: 'anon', deviceId: null };
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}
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module.exports = { resolveIdentity, ANON_KEY };
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