s8n
ab1f607df6
4 parallel research agents output (2026-05-07): - RESEARCH-2B2T-QUEUE.md — 2b2t queue tech deep-dive: architecture, drama timeline, 5 patterns to copy + 5 to avoid - RESEARCH-LIMBO-PLUGIN-SURVEY.md — open-source plugin survey: STEAL list (Elytrium LimboAPI/LimboAuth + PistonQueue), PATTERN list, SKIP list - V2-ARCHITECTURE.md — Paper-only stack with Velocity-ready seam, 7-state login flow, snapshot-on-pre-login, transparent FIFO trust tiers - V2-ROADMAP.md — M0-M5 milestones with acceptance criteria + dep graph Stack decision: Paper-only for now (no proxy required), but architecture split into Gatekeeper + Restore layers so future Velocity migration is mechanical. Trip-wires codified for when to reconsider. Anti-drama policy locked in code (not config): no paid priority, no hidden veteran tier, transparent ban appeals. Bootstrap repo at git.s8n.ru/s8n/auth-limbo-v2 ready for M0 work.
165 lines
7.2 KiB
Markdown
165 lines
7.2 KiB
Markdown
# RESEARCH — Limbo / Queue / Auth Plugin Survey
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Read-only research feeding **AuthLimbo v2**. 2026-05-07.
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---
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## 1. TL;DR
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**Top-3 STEAL** (vendor / shade / depend):
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1. **Elytrium LimboAPI** (AGPL-3.0, Velocity) — virtual fake-server
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primitives at the Velocity packet layer. License-compatible, exactly
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the abstraction we need for "hold pre-login on the proxy, never let
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the player touch the Paper world".
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2. **Elytrium LimboAuth** (AGPL-3.0, Velocity) — production auth flow
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built on LimboAPI. AuthMe-import path, BCrypt+TOTP, weak-password
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list. We can fork or depend; AGPL == AGPL.
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3. **PistonQueue** (Apache-2.0, Bungee+Velocity+Bukkit) — closest
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open-source 2b2t-style queue, actively maintained, permissive
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license (we can shade safely into AGPL).
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**Top-3 PATTERN** (read & re-implement):
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1. **AnarchyQueue (zeroBzeroT)** — clean Velocity/Paper split, separate
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queue-server, position-update cadence; small enough to read
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end-to-end.
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2. **LeeesVelocityQueue** — minimal MIT priority/bypass model; good
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reference for *non-paid* trust-tier permissions.
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3. **LimboFilter** — anti-bot CAPTCHA + packet-prep tricks; pattern
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only since AGPL fork would entangle us further.
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**Stack decision:** **Velocity + Paper, both required.** Pre-auth
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holding belongs at the proxy (LimboAPI virtual server) — Paper-only
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can't truly hide the world. Paper plugin keeps the post-auth
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chunk-preload + void-guard from current AuthLimbo. See §3.
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---
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## 2. Per-plugin detail
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| Plugin | License | Stack | Last release | Status | Rating |
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|---|---|---|---|---|---|
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| Elytrium LimboAPI | AGPL-3.0 | Velocity | 1.1.26 (2024-09) | Active, slowing | STEAL |
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| Elytrium LimboAuth | AGPL-3.0 | Velocity (LimboAPI) | 1.1.14 (2024-06) | Active | STEAL |
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| Elytrium LimboFilter | AGPL-3.0 | Velocity (LimboAPI) | 1.1.18 (2024-06) | Active | PATTERN |
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| PistonQueue (AlexProgrammerDE) | Apache-2.0 | Velocity+Bungee+Bukkit | 4.0.0 (2026-04) | Very active | STEAL |
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| AnarchyQueue (zeroBzeroT) | custom permissive (no-warranty) | Velocity | 3.0.13 (2025-10) | Active | PATTERN |
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| LeeesVelocityQueue | MIT | Velocity | 1.0.1 (2025-07) | Light, alive | PATTERN |
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| ajQueue | GPL-3.0-only | Velocity+Bungee+Paper | active 2.x | Active | PATTERN (license clash w/ AGPL is one-way OK) |
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| McMackety/velocity-queue | GPL-3.0 | Velocity (Kotlin) | 1.1.2 (2021-06) | **Archived** | SKIP |
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| Shirodo-Queue | MIT | Bungee | none | Hobby | SKIP |
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| ProjectPersistence/queue | n/a | mixed | n/a | **404** | SKIP |
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| NanoLimbo (Nan1t) | GPL-3.0 | standalone+proxy fwd | 1.12.0 (2026-04) | Active | PATTERN (no auth/queue, but reference impl) |
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| NanoLimboPlugin (bivashy) | GPL-3.0 | Velocity+Bungee | 1.8.1 (2024-06) | Maintenance | PATTERN |
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| AuthMe-Reloaded | GPL-3.0 | Spigot/Paper/Folia/Bungee/Velocity | 5.7.0 (2026-04) | Active | KEEP (current dep, not a v2 base) |
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| kennytv/Maintenance | GPL-3.0 | Paper/Bungee/Velocity/Sponge | active | Active | PATTERN (motd + whitelist gate UX) |
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| EaglerProxy | n/a | JS shim | active | Off-target | SKIP — not our threat model |
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| TitanProxy | closed-source | n/a | n/a | n/a | SKIP |
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Notes:
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- **NanoLimbo ≠ NanoLimboPlugin.** Former is a standalone Netty
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server; latter wraps it as a proxy plugin. Neither does auth.
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- **ProjectPersistence/queue** URL 404'd; treat as dead.
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- **McMackety/velocity-queue** archived 2021-08; Kotlin code is
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readable but do not depend.
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---
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## 3. Recommended architecture for AuthLimbo v2
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```
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client ──► Velocity proxy ──► [LimboAPI virtual server: auth + queue]
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│
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▼ (only after auth+queue cleared)
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Paper backend ──► [auth-limbo Paper plugin:
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chunk-preload, void-guard,
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inventory snapshot]
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```
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### Velocity side (new module `auth-limbo-velocity`)
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- **Depend:** `com.velocitypowered:velocity-api:3.4.x`
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- **Depend (compileOnly+shade):** `net.elytrium:limboapi:1.1.26`
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(AGPL — fine, we are AGPL).
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- **Vendor / fork:** parts of `LimboAuth` for the auth state-machine
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(BCrypt verify against AuthMe schema, TOTP, weak-password list). Do
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not pull the H2/MySQL stack — read AuthMe's existing SQLite directly
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to keep one source of truth.
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- **Queue logic:** port PistonQueue's `QueueListener` + position
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ticker (Apache-2.0 → AGPL is a clean re-license). Strip its paid
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tiers; replace with permission-based trust tiers
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(`authlimbo.priority.trusted`, `.regular`, no `.donor`).
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- **Anti-bot:** PATTERN from LimboFilter — client-brand check + join
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rate-limit; skip the CAPTCHA for now (UX cost too high for a
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small server).
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### Paper side (existing `auth-limbo` plugin, becomes
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`auth-limbo-paper`)
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- Keep current chunk-preload + void-world generator.
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- Land ROADMAP F1 (void-damage guard), F2 (TP retry), F3 (3×3
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preload), F5 (inventory snapshot) — these are *post-auth* defences
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and remain Paper-side.
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- Drop responsibility for "hide world pre-auth" — Velocity holds it
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now.
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### Shared
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- Plugin-message channel `authlimbo:handshake` carries `{uuid,
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trust-tier, reconnect-token}` Velocity → Paper so the Paper side
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knows the player already passed auth+queue and skips its own login
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gate.
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### Maven coords
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`net.elytrium:limboapi-api:1.1.26` (AGPL, compileOnly),
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`com.velocitypowered:velocity-api:3.4.0` (MIT),
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`AlexProgrammerDE/PistonQueue:4.0.0` (Apache-2.0, study),
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`io.papermc.paper:paper-api:1.21.11-R0.1` (GPL-3.0, compileOnly).
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---
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## 4. License compatibility matrix
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Outbound: AuthLimbo v2 = **AGPL-3.0**. Inbound combinations:
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| Source license | Compatible direction | Action |
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|---|---|---|
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| AGPL-3.0 (LimboAPI/Auth/Filter) | bidirectional | depend or shade freely |
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| GPL-3.0 (NanoLimbo, ajQueue, AuthMe, Maintenance) | one-way (GPL → AGPL ok) | depend; cannot upstream patches without coordination |
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| Apache-2.0 (PistonQueue) | one-way (permissive → AGPL) | shade or copy with NOTICE |
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| MIT (LeeesVelocityQueue, Shirodo) | one-way | shade or copy with attribution |
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| Custom no-warranty (AnarchyQueue) | unclear | **read code, do not vendor**; re-implement |
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| Closed (TitanProxy, EaglerProxy logic) | n/a | skip |
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AGPL §13 invariant: if we ship a network service modified from
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LimboAuth, source must be offered. Forgejo `git.s8n.ru` already
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satisfies this for our fleet.
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---
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## 5. Risks
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1. **Elytrium upstream slowdown** — last release mid-2024. Pin to
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tag, plan soft-fork at git.s8n.ru for 1.21.11+ protocol fixes.
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2. **AGPL §13** — modified network deploys need source-link. Footer
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+ `/authlimbo source` covers it.
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3. **PistonQueue size** — selective copy beats shading whole jar.
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4. **AnarchyQueue licence ambiguity** — no-warranty header not OSI;
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read-only.
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5. **Velocity↔Paper handshake** is a new failure mode; need
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integration test before deploy.
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6. **No CAPTCHA** = bot-flood exposure. Acceptable for small private
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server; revisit if we open up.
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7. **Reconnect token storage** (SQLite vs in-memory) still pending.
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---
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## 6. Sources
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Elytrium/{LimboAPI,LimboAuth,LimboFilter}, Nan1t/NanoLimbo,
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bivashy/NanoLimboPlugin, AlexProgrammerDE/PistonQueue,
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zeroBzeroT/AnarchyQueue, XeraPlugins/LeeesVelocityQueue,
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McMackety/velocity-queue (archived), ShirodoBurak/Shirodo-Queue,
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AuthMe/AuthMeReloaded, kennytv/Maintenance, modrinth/ajqueue.
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