- .gitignore (target/, node_modules/, .worktrees/, Cargo.lock) - AGENTS.md: project conventions adapted from alktunnels for the SOCKS5 wrapper crate (no-forced-binding posture, fast-socks5 genericity, producer/consumer vocabulary, upstream-asks rule, verification commands with the wasm caveat for OQ-SK-04) - docs/research/phase-0.md: Phase 0 draft — vision, prior art (fast-socks5 surface, alktunnels -D conclusion, alknet ADR-090 client, noq trait-shape divergence), open questions OQ-SK-01..07, POC candidates, convergence checklist - sdd_process.md: package name fixed (alkcall -> alksocks)
336 lines
18 KiB
Markdown
336 lines
18 KiB
Markdown
# AGENTS.md
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Operating instructions for opencode agents working in this repo. opencode
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auto-loads this file as instructions, overriding the built-in defaults for
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this project. Custom agents in `.opencode/agents/` inherit these rules
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unless their own prompts say otherwise.
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## Git Workflow
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**Commit and push when reasonable.** When a change is complete and
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verified (build + lint + tests pass), commit and push to `origin/main`
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without asking. This overrides the built-in default of "only commit when
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explicitly asked."
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The workflow:
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1. Make the change
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2. Verify: `cargo test`, `cargo clippy --all-targets -- -D warnings`,
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`cargo fmt --check`, `cargo doc --no-deps` if docs changed
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3. Inspect `git status` and `git diff` before staging — stage only the
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intended files, never secrets
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4. Write a concise commit message matching the repo style (see `git log
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--oneline -10`). For multi-point changes, use a summary line plus a
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body with bullet points and a verification block.
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5. `git push origin main`
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6. Report the commit hash and the verification summary
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Exceptions — **do not** commit or push without asking:
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- The change is exploratory / speculative (you're not sure the user wants
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it kept)
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- The user is actively reviewing the diff and may ask for changes
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- The change touches the wire format or a trait shape that backends or
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consumers implement (one-way doors — see "Wire formats are stable" and
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"Backend trait shapes are one-way doors" below; once consumers exist,
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those signatures are wire-stable contracts)
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- You'd be force-pushing, amending a published commit, creating an empty
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commit, or skipping hooks
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Never commit secrets, keys, or credentials. If a commit fails or hooks
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reject it, fix the issue and create a new commit — do not amend the
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failed one.
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Git identity is preconfigured (`glm-5.3-flash <glm-5.3-flash@alk.dev>`). Do
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not change `git config`, skip hooks, or use `git commit -i`.
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## Project Conventions (Rust / SOCKS5 protocol crate)
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This is the SOCKS5 protocol crate — a wrapper around `fast-socks5` that
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offers the SSH `-D` (dynamic / SOCKS5 proxy) capability alongside
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alktunnels' `-R` and `-L`, composed with alkcall channels ("ALPN as a
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service"). It sits in the alk* family: alkcall (call + channels — the
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substrate), alktty (terminal sessions), alktunnels (arbitrary `-L`/`-R`/
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tunnels). The distinguishing posture of this crate: **the SOCKS5 server
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never binds a port unless explicitly configured to** — the protocol is
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served inside alkcall channels data channels (a produced, ACL-scoped
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resource), not on a kernel socket. A local bind is one optional
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assembly-layer shape, not the protocol's home. The conventions below
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apply to all work in `src/` and `tests/`. They mirror
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`.opencode/agents/implementation-specialist.md` §Project Conventions and
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are repeated here so they apply to every session, not just spawned
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implementation agents.
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1. **No comments in code** unless the user explicitly asks. This is a
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project-wide convention. Doc comments (`///`, `//!`) are fine and
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expected on public API. Inline `//` comments only when the user asks
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or when a non-obvious safety/correctness constraint would otherwise
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be missed (e.g., "a two-pump tunnel must shut down the opposite sink
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on pump completion — `try_join!` alone deadlocks; see alkcall
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ADR-050's `pump_bidi` / alknet ADR-078").
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2. **Error handling** — `thiserror` for library error types; map SOCKS5
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reply codes (`fast_socks5::ReplyError`) faithfully per RFC 1928. No
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panics in library code. No `unwrap()` or `expect()` outside tests. If
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you reach for `unwrap`, the error path wasn't specified — stop and
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decide what should actually happen. For poisoned `RwLock`/`Mutex`,
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use `unwrap_or_else(|e| e.into_inner())` so a panic in one operation
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does not cascade to other operations.
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3. **`tokio` is the async runtime** — all I/O is async. `fast-socks5` is
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tokio-native; the wrapper's protocol layer, pumps, and client session
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types are all async. Use `tokio::sync` primitives (`oneshot`, `mpsc`)
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for lifecycle correlation. Any non-wasm backend module (local TCP
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listener for a "real" `socks5://` endpoint) lives behind a feature
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flag like alktty/alktunnels' `local`.
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4. **WASM target is load-bearing (by default)** — the default crate
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(protocol-only) should compile to `wasm32-unknown-unknown`, following
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the alktty/alktunnels precedent. Use the wasm-clean tokio subset
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(`rt`, `sync`, `io-util`, `macros`, `time`) — **do NOT use `features
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= ["full"]`** — and keep socket/platform I/O feature-gated. Note:
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`fast-socks5` itself uses `tokio::net` and `socket2` unconditionally;
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whether it compiles wasm-clean, needs a fork, or the wrapper
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reimplements the SOCKS5 state machine over `tokio::io` generics is an
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open question (see `docs/research/phase-0.md` OQ-SK-04) — do not
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assume either way until it is resolved.
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5. **Wire format is stable** — the SOCKS5 protocol itself is RFC 1928
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(fixed); this crate's wire surface is the ALPN + the channel open-op
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params that carry it. Those params are a one-way door once consumers
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exist. Follow the alktunnels precedent: params are a self-contained
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JSON object identifying the produced resource (alkcall ADR-039 —
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`params` is ALPN-specific, interpreted by the open handler). Any
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params-format ADR must be written before the first consumer exists;
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after that, changes are additive-only.
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6. **Producer/consumer, not server/client** — both sides of a channels
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connection can initiate. A producer exposes the SOCKS5 service
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(registers openable channels via `ChannelCore::register_openable`); a
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consumer opens SOCKS5 channels and speaks RFC 1928 inside them. Both
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sides can be both simultaneously — connection direction (who opened
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it) is independent of service direction (who dials targets, who
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serves). Avoid "server" and "client" framing in docs and API names;
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use "producer" and "consumer," or "accept side" / "connect side" for
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the connection-establishment half specifically. (SOCKS5's own
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client/server roles are RFC vocabulary and keep their RFC names
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inside the protocol layer.) See alkcall ADR-022, ADR-037.
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7. **Substrate-agnostic by construction** — the protocol layer must not
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know whether the far side of a SOCKS5 connection is a kernel TCP
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socket, a channels `BiStream`, a unix socket, or an in-process pipe.
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`fast-socks5`'s explicit server API is generic over
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`T: AsyncRead + AsyncWrite + Unpin` (`Socks5ServerProtocol<T, ...>`,
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`transfer(inbound, outbound)`); the wrapper must preserve that
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genericity — the channels adapter feeds the SOCKS5 state machine a
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`BiStream` (which is `AsyncRead + AsyncWrite`), the local backend
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feeds it a `TcpStream`. Substrate-specific types are confined to
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feature-gated backend modules, injected at the assembly layer — the
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same inversion-point pattern as alktty's `TtyBackend` and
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alktunnels' pump halves.
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8. **Two-pump shutdown-on-completion is a contract** — the SOCKS5
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CONNECT data plane is the canonical two-pump shape (one pump per
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direction). Each pump MUST shut down the opposite sink when it
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completes; `tokio::try_join!` alone deadlocks. The helper is pinned
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upstream as alkcall `channels::pump_bidi` (ADR-050, review 007 R-03)
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— use it; do not hand-roll the two-pump shape. The channels layer
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drops all per-channel senders on transport EOF — rely on that for
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teardown, and emit EOF sentinels (zero-length chunks) on clean sink
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shutdown. Await `pump_bidi` inline inside the `OpenHandler`'s task —
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the returned `JoinHandle` must track the data-plane lifetime (R-02;
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early return = teardown-at-birth).
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9. **No forced local binding** — the defining requirement of this crate.
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The SOCKS5 server must run without binding any port: the RFC 1928
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conversation is carried inside a channels data channel, and target
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dials happen on the producing side (or hop further through
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alktunnels/alksocks). A local bind (a genuine `socks5://host:port`
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endpoint) is an optional assembly-layer/feature-gated capability.
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UDP ASSOCIATE is the hard case: RFC 1928 replies with a UDP relay
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address and the client sends datagrams to it, which seems to demand a
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bind — how the relay address is virtualized (or the associate shape
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adapted) is a Phase 0 question (OQ-SK-03). Binding decisions belong
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to the caller (assembly layer), never the protocol crate.
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10. **Backpressure and limits are inherited, not redefined** — bounded
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per-channel buffers, the 256-channel per-connection cap, monotonic
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channel IDs, and the zero-length-sentinel EOF convention are
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alkcall channels invariants (see alkcall ADR-040/041/034). The
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crate consumes them via `ChannelCore`/`ChannelClient`; do not build
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a second demux/mux or re-derive limits. SOCKS5 CONNECT is a single
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stream per open (no sub-demux inside the channel) — one channel per
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SOCKS5 session, no protocol-level flow key.
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11. **Vendored core types come from alkcall** — `Connection`,
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`ProtocolHandler`, `BiStream`, `BidiStreamSource`, `AuthContext`,
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`Identity`, `IdentityProvider`, `AccessControl`,
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`OwnershipProvider`, `HandlerError`, `StreamError` come from
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`alkcall::core`. Do not vendor copies into this crate. alkcall is
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v0.7.x — breaking changes are expected at this major-zero stage;
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this is an early consumer, so we find and fix issues upstream
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rather than working around them. Pin `alkcall = "0.7.1"` and bump
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deliberately. The establishment surface (alkcall ADR-049 +
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amendment 2) is load-bearing for this crate: SOCKS5 session opens
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use `register_openable_with_establisher` so a refused/auth-failed
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session is a typed `channel:open_failed` call error, never a
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phantom channel; the establisher returns the negotiated handle via
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`Establishment::new(plan)` (typed-opaque `ChannelPlan` — payloads
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must be `Send + Sync`). The 0.7.0 identity surface (ledger
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CF-005/CF-006) is load-bearing for auth mapping: the per-call
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opener identity arrives on the open-op hooks — map it to SOCKS5
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credentials/ACL there, not via any in-band SOCKS auth unless
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clients need RFC-facing username/password.
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12. **Access control** — the producer's openable channels get
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authorization for free via `ChannelCore::register_openable`, which
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wires `AccessControl` into the operation spec (the registry runs
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the ACL before the open handler). Scope-gate SOCKS5 opens (e.g.
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`SOCKS5_OPEN_SCOPE`, shape following alktty's `TTY_OPEN_SCOPE`) and
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optionally consult `OwnershipProvider` for resource ownership.
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SOCKS5 is arbitrary-egress by nature — treat the open gate and the
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target policy as the security boundary; per-target allowlists (if
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any) are a producer-side policy question for Phase 1 (OQ-SK-05).
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See alknet ADR-024 (registry layering, alkcall ADR-019), alknet
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ADR-050 (ownership, alkcall ADR-011), and alktunnels' resolved
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posture (target selection lives in the SOCKS5 protocol at the
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producing side; whatever ACL governs the socks5 resource governs
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everything reachable through it).
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13. **Feature flags** — substrate backends are feature-gated if the
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need arises. The base crate should compile lean (no socket/platform
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deps unless the feature is on). Verify both `cargo test` (default)
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and `cargo test --all-features` pass if features are added.
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14. **Naming** — Rust standard: `snake_case` for functions/variables/
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modules, `PascalCase` for types/traits, `SCREAMING_SNAKE_CASE` for
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constants.
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15. **Module structure** — one module per file under `src/`, re-exported
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from `src/lib.rs`. Public API surface is `lib.rs` re-exports. The
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expected shape (pending Phase 1 pinning): the SOCKS5 protocol
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wrapper (server state machine + client session), the channels
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adapter (producer half — open handler for this crate's ALPN), the
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consumer half (a typed client that opens SOCKS5 channels and
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speaks RFC 1928 through them), and feature-gated backend modules
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(the optional local-bind listener). Backend modules are
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feature-gated and never imported from the protocol/adapter/client
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modules.
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16. **ALPN naming** — this crate owns a `alk/`-prefixed ALPN (provisional
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`alk/socks5`; final naming per alkcall ADR-004/ADR-006 convention).
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One ALPN per protocol. The ALPN string is wire-stable once
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published — decide via ADR before the first consumer.
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17. **Upstream is ours — make asks early.** We own `fast-socks5`
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(`/workspace/fast-socks5`, v1.0.0, MIT) and alkcall. If the wrapper
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needs a change upstream (a typestate hook, a generic split, a new
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event), file it and land it there rather than working around it
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locally — the alktunnels precedent (the E-01/E-02 sweep, filed from
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its Phase 0 and landed in alkcall 0.5.0 within a day). Keep
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`/workspace/fast-socks5` as the reference checkout; if upstream
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diverges from what we publish, note the fork point in the research
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docs.
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## Verification Commands
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Run these before committing. All must pass.
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```bash
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cargo test # full suite
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cargo clippy --all-targets -- -D warnings
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cargo fmt --check
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cargo doc --no-deps # if docs changed
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cargo test --all-features # if features are added
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cargo check --target wasm32-unknown-unknown # default crate stays wasm-clean
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cargo clippy --target wasm32-unknown-unknown -- -D warnings
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cargo publish --dry-run --allow-dirty # before a release
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```
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The wasm check is the structural guard for the "default crate is
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wasm-clean" invariant (same as alktty/alktunnels) — run it whenever a
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non-backend module changes. Until OQ-SK-04 (fast-socks5 wasm posture) is
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resolved, the wasm check may fail on the dependency graph; that failure
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is expected and is exactly what the OQ tracks.
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## Architecture Context
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- `docs/research/phase-0.md` — the Phase 0 (Exploration) document and
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the current state of this repo: vision, prior art, open questions
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(OQ-SK-01..NN), and POC candidates. Read it before non-trivial work.
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The SDD process lives in `docs/sdd_process.md` (Phase 0 in progress;
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`docs/architecture/` does not exist yet).
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- The prior art for this crate:
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- **alktunnels** — `/workspace/@alkdev/alktunnels` (v0.1, the closest
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sibling): the producer/consumer tunnel crate on alkcall channels.
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Its Phase 0 findings (`docs/research/phase-0-findings.md`) settled
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the hub-owns-the-connection model, the two-pump shape, the
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establishment story (alkcall ADR-049), and the `-D`-composes-at-the-
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assembly-layer conclusion — this crate is that conclusion's
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realization. Its Phase 1 ADRs (params shape, ALPN strategy,
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access-control posture) are the template for this crate's Phase 1.
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- **alktty** — `/workspace/@alkdev/alktty` (v0.4): the first
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producer/consumer protocol crate on alkcall channels; the backend
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inversion point, wasm-clean default crate, and feature-gated local
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backend precedents.
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- **alkcall** — `/workspace/@alkdev/alkcall` (v0.7.1, crates.io). The
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substrate: call protocol + channels multiplexing. This crate
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consumes `alkcall::core` types and the channels
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`ChannelCore`/`ChannelClient`/`register_openable_with_establisher`
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surface, same as alktty/alktunnels.
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- **fast-socks5** — `/workspace/fast-socks5` (v1.0.0, MIT, we own
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upstream). The SOCKS5 implementation to wrap: explicit typestate
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server API (`Socks5ServerProtocol<T, states::*>`), generic over
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`T: AsyncRead + AsyncWrite + Unpin`; `run_tcp_proxy` /
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`run_udp_proxy_custom` / `transfer` are the interception points;
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client side has `Socks5Stream` (generic over the backing socket)
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and `Socks5Datagram` (UDP associate).
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- **alknet's SOCKS5 client** —
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`/workspace/@alkdev/alknet/crates/alknet-client/src/socks5.rs`
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(ADR-090): the client-side example need — `Socks5UdpSocket`
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implements `quinn::AsyncUdpSocket` so QUIC rides SOCKS5 UDP
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ASSOCIATE. Validated by the quinn-proxy POC
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(`/workspace/@alkdev/alknet/docs/research/quinn-quic-proxy/
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findings.md`). The open question for this crate's client story: the
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same trait impl against **noq** (iroh's quinn fork,
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`/workspace/noq` — `noq::AsyncUdpSocket`, `Endpoint::
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new_with_abstract_socket` exist but with a different surface shape;
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see OQ-SK-06).
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- Key upstream ADRs that inform this crate's design (alknet numbers;
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alkcall's ports live in `/workspace/@alkdev/alkcall/docs/architecture/
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decisions/`):
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- alknet ADR-093 / alkcall ADR-035 — channels pure channel
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multiplexing (8-byte header, no `stream_type`); the SOCKS5 session
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rides inside the channel's `BiStream`
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- alknet ADR-078 / alkcall ADR-050 — two-pump shutdown-on-completion;
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the helper is pinned upstream as `alkcall::channels::pump_bidi` —
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use it, do not hand-roll
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- alkcall ADR-049 (amendment 2) — the establishment phase; the
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establisher returns the negotiated handle via `Establishment::new`
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(typed-opaque `ChannelPlan`, `Send + Sync` payload constraint)
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- alknet ADR-074 / alkcall ADR-038 — `ChannelConnection` as a
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`BidiStreamSource`; every handler receives a `Connection`
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- alknet ADR-075 / alkcall ADR-039 — `ChannelsAdapter` /
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`ChannelManager` (substrate-agnostic demux; `params` is
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ALPN-specific — for this crate, the SOCKS5 service identity/policy)
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- alknet ADR-071 / alkcall ADR-034 — channels wire format (one-way
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door); alkcall ADR-036 — channel 0 is pre-negotiated `alk/call`;
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alkcall ADR-037 — channel lifecycle operations (`channel/open` on
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channel 0)
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- alkcall ADR-042 — hub relay; alktunnels' hub-proxy refinement —
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the hub terminates and re-produces per-hop ACL (a SOCKS5 resource
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is the same shape, "further downstream" — alktunnels
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phase-0-findings §Prior art)
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- alkcall ledger CF-005/CF-006 (0.7.0) — the connect-side serving
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identity seam: caller identity precedence (token >
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`ServingConfig.identity` > transport), per-call opener identity on
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the open-op hooks
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- The suite decomposition context: alknet was the massive POC ("vpn-like
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without being a vpn" + transport agnosticism) being rewritten; this
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crate extracts and improves its SOCKS5 story (client side: ADR-090's
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proxy support; server side: the `-D` capability alktunnels deferred
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to composition). `alknet-client/src/socks5.rs` and the quinn-proxy
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POC findings are the direct ancestors of this crate's client work.
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- If a TODO references a design direction that a later ADR has decided
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against, the TODO is stale — remove it and align with the ADR. Do not
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implement the rejected design. |