alksocks/docs/architecture

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status: draft last_updated: 2026-09-21 (the vendor extraction amendment — ADR-011 §Amendment, ADR-009 §Amendment; Phase 1 initial draft 2026-09-20 — the OQ-SK ledger promoted into ADRs 001-012 and open-questions.md)

alksocks — Architecture

A SOCKS5 (RFC 1928) producer/consumer protocol crate on alkcall channels: an arbitrary-egress proxy service that never binds a port unless explicitly configured to — the alk/socks5-family producer/consumer protocol crate, the sibling of alktty (alk/tty) and alktunnels (alk/tunnel). Where alktunnels realizes the -L/-R forwarding flavors, alksocks realizes the -D flavor (dynamic / SOCKS5 proxy). This directory holds the architecture spec docs and the ADRs.

Current State

Phase 1 (Architecture) — initial draft. Phase 0 (docs/research/phase-0.md) is converged (2026-09-14) and POC-complete (all numbered POCs passed or were dropped with the scope decision); the OQ-SK ledger's Phase 1 inputs are collected and promoted into ADRs 001–012. All docs are draft — they transition to reviewed when their open questions resolve and the architecture review passes. src/ does not exist yet; implementation follows the decomposition phase.

Documents

Document	Status	Description
overview.md	draft	Crate purpose, the resource model in brief, dependencies, feature gates, module map
wire.md	draft	The wire format: the open op (trivial params — ADR-001), the phase model, the data planes (CONNECT pass-through / ASSOCIATE frames / BIND phases), sentinels
producer.md	draft	The producer half: the session-gate establisher, command dispatch, the three seams (dial/egress/accept), scope gates, the local backend
consumer.md	draft	The consumer half: the channels-native sessions (connect/associate/bind), the front doors, door auth (ADR-005), teardown ownership
vendor.md	draft	The inline vendor: the extracted fast-socks5 subset's scope (extraction, not wholesale copy), the two carried changes, the maintenance posture
bast.md	draft	The BAST document for the ASSOCIATE datagram frame (ADR-003); pass-through stages have no binary framing to describe
open-questions.md	draft	Centralized OQ tracker (OQ-SK-01..09 promoted; new questions as OQ-SK2-06.. — the SK2 numbering is not contiguous from 01, working-draft numbers were consumed)

ADR Table

ADR	Title	Status
001	ALPN, Open Op, and Trivial Params	Accepted
002	Protocol Base — the Vendored fast-socks5 Typestate Subset	Accepted
003	The Handle Swap — one Channel per Association, Frames In-Band	Accepted
004	The Dial-Callback Shape — Function, not Trait, at Three Seams	Accepted
005	Auth Mapping — "Both," Split by the Door	Accepted
006	Access-Control Posture — the Open Gate Plus the Command Gate	Accepted
007	BIND in the Base Crate — the Phase Model Extended	Accepted
008	Egress/Accept Provider Defaults — Local Socket and Composed (Direct Op)	Accepted
009	Feature-Gate Layout — local and the Composition Boundary	Accepted (amended 2026-09-21)
010	Channel Capacity — Proxy-Workload Recommendation, Not a Wire Change	Accepted
011	the Inline Vendor — fast-socks5's T-Generic Subset, In-Tree	Accepted (amended 2026-09-21)
012	Target Policy and the Virtual-Subnet Translation Layer	Accepted

Upstream ADRs (alkcall/alktunnels/alknet) are referenced by their own numbers and are NOT ported — the alkcall originals at /workspace/@alkdev/alkcall/docs/architecture/decisions/ remain authoritative for the shared surfaces (establishment, channels wire format, pump_bidi, identity seam, the channel caps).

Key Design Principles

1. The protocol never binds. The SOCKS5 service is a produced, ACL-scoped resource on a channels connection ("ALPN as a service"); kernel binds exist only as the two explicit, optional, feature-gated assembly shapes (the producer's local backend; the consumer's front door). The binding decision belongs to the caller. The UDP ASSOCIATE "bind" is virtualized as the channel (the handle swap, ADR-003).
2. The RFC conversation is the data plane. One ALPN, one open op, trivial params (ADR-001); the phase model needs no mode byte — the reply synchronizes the switch; no in-band control vocabulary (the escape hatch is a new ALPN, never a framing change).
3. The seams are functions, not traits (ADR-004): DialFn / EgressFactory / BindAcceptFactory at the three I/O planes; the protocol layer never names a substrate type; ownership rides the handle structurally.
4. Auth is split by the door (ADR-005): producer = the identity seam; the front door = RFC 1929 + the credential→identity static mapping.
5. Two grants, clean separation (ADR-006): socks5:open (egress) and socks5:bind (ingress listeners) — never implied by each other; target policy = the dialer.
6. Backpressure and limits are inherited, not redefined (the alkcall channels invariants); the one-channel-per-session convention holds for all three commands; the proxy-workload cap posture is ADR-010 (config, not wire).
7. Wasm-clean default crate (ADR-009): the default crate is protocol-only; the vendor is an extraction with zero kernel-net code — there is no net feature (ADR-011 §Amendment); local is opt-in and non-wasm; composed rides alktunnels' wasm-clean default (verified with the wasm check at implementation).
8. The vendor is first-class (ADR-011): the T-generic subset extracted in-tree with two carried changes (BIND, new_reply); /workspace/fast-socks5 stays the differential-testing reference and the only place the full upstream surface (the kernel-net region) exists; nothing waits on upstream.

Document Lifecycle

Status	Meaning	Transitions
draft	Under active development; may change significantly	→ reviewed when the doc's open questions resolve
reviewed	Architecture is final; implementation may begin	→ stable when implementation is complete and verified
stable	Locked; changes require review, may warrant an ADR	→ deprecated when superseded
deprecated	Superseded; kept for reference	Removed when no longer referenced

References

• Phase 0: docs/research/phase-0.md (the OQ ledger + convergence), the POC findings files, docs/research/iroh-socks5-eval.md
• The SDD process: docs/sdd_process.md (Phase 1's process; the task format; the deferred-OQ blocker-task half)
• Upstream: alkcall ADR-037/039/047/049/050/040/041/051, ledger CF-005/CF-006; alktunnels ADR-003/004/006/007/008 + the graduation research; alknet ADR-078/090
• Siblings: alktty (/workspace/@alkdev/alktty), alktunnels (/workspace/@alkdev/alktunnels)
• Reference checkout: /workspace/fast-socks5 (v1.0.0, MIT, third-party — the differential-testing reference)
• RFC 1928, RFC 1929; tun2proxy (/workspace/tun2proxy)