From d758a71490752cec09e59cc7b608d1e5bcadcecf Mon Sep 17 00:00:00 2001 From: "glm-5.2" Date: Thu, 25 Jun 2026 08:06:45 +0000 Subject: [PATCH] =?UTF-8?q?docs(research):=20alknet-ssh=20phase-0=20findin?= =?UTF-8?q?gs=20=E2=80=94=20stream=20wiring,=20russh=200.60.2,=20decision?= =?UTF-8?q?=20points?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Phase 0 exploration for alknet-ssh: confirms SSH-over-QUIC-bistream via tokio::io::join (no custom adapter needed, per reference impl), russh 0.60.2 generic run_stream/connect_stream, and channel-into-bistream multiplexing. Surfaces 9 decision points for Phase 1: host key sourcing (vault-derived vs config), channel policy v1 surface, client + SOCKS5 crate split, crypto backend, auth method coverage, and a stream-handling POC to close russh's upstream test gap. --- docs/research/alknet-ssh/phase-0-findings.md | 450 +++++++++++++++++++ 1 file changed, 450 insertions(+) create mode 100644 docs/research/alknet-ssh/phase-0-findings.md diff --git a/docs/research/alknet-ssh/phase-0-findings.md b/docs/research/alknet-ssh/phase-0-findings.md new file mode 100644 index 0000000..1f9d524 --- /dev/null +++ b/docs/research/alknet-ssh/phase-0-findings.md @@ -0,0 +1,450 @@ +--- +status: draft +last_updated: 2026-06-25 +--- + +# alknet-ssh — Phase 0 Research Findings + +This document captures Phase 0 (Exploration) findings for the `alknet-ssh` +crate. The objective of Phase 0 per `docs/sdd_process.md` is: *"Capture vision +and guiding principles; research options; validate approaches; converge on a +recommended approach."* It is the input to Phase 1 (Architecture), where the +Architect will produce `docs/architecture/crates/ssh/*.md` specs, ADRs, and open +questions. + +## Vision Recap + +`alknet-ssh` is the SSH protocol handler for the ALPN-as-service architecture +(ADR-001). It registers the `alknet/ssh` ALPN on the shared `AlknetEndpoint` +and implements the `ProtocolHandler` trait (ADR-002, ADR-007). + +The guiding insight, carried over from the reference implementation at +`/workspace/@alkdev/alknet-main/`, is: + +> **SSH does not care where its underlying byte stream comes from.** + +The reference implementation built on this — it ran the russh SSH-2 state +machine over a `Transport`-produced duplex stream (`AsyncRead + AsyncWrite + +Unpin + Send`) rather than over its own TCP sockets. The greenfield rebuild +keeps the insight and drops the messy transport-abstraction layer that grew +around it: in the new model the `AlknetEndpoint` hands the handler a `Connection` +(quinn/iroh QUIC), and the handler is responsible for opening/accepting the +bidirectional QUIC stream that carries the SSH-2 protocol. + +The reference implementation reportedly has 3.5k clones in the past 14 days, so +there is real-world demand for the "SSH-over-arbitrary-stream" capability. The +greenfield rewrite is a total rewrite except most of the vault was initially +copied (also since rewritten). + +## Sources Investigated + +| Source | Path | Note | +|--------|------|------| +| Existing arch docs (core) | `docs/architecture/crates/core/*` | ProtocolHandler, Connection, BiStream, AuthContext, IdentityProvider, Endpoint | +| Existing ADRs 001–027 | `docs/architecture/decisions/*` | All Accepted; ADR-002/007/010/004/011 most relevant to SSH | +| russh reference deep-dives | `docs/research/references/ssh/russh/01-06` | Already authored; covered overview, keys, protocol, crypto, internals, usage | +| russh source (authoritative) | `/workspace/russh/` | Checked out at `Cargo.toml` version `0.60.2`. The cargo registry cache only contains `russh-0.49.2` — older and NOT the intended version. **Use `/workspace/russh/` as the canonical 0.60.2 reference.** | +| alknet Cargo.lock | `Cargo.lock` | Does **not** yet contain a russh entry — russh is not wired into the workspace dependency graph yet | +| Reference implementation | `/workspace/@alkdev/alknet-main/` | `crates/alknet-core/src/{interface/ssh.rs, server/handler.rs, server/serve.rs, transport/*, client/*}` | + +> **Note on the russh clone**: the `/workspace/russh` checkout was inspected and +> its `russh/Cargo.toml` declares `version = "0.60.2"` with `edition = "2024"` +> and MSRV 1.85 — matching the research references. The agent flagged the +> cargo-cache mismatch; verifying against the checkout rather than the cache is +> the safe choice since 0.49.2 → 0.60.2 spans major API changes +> (`server::run_stream` generic signature, `Auth` enum shape, `server::Handler` +> method set all differ). When alknet-ssh's `Cargo.toml` pins `russh = "0.60"`, +> Cargo will fetch the matching 0.60.x into the cache, at which point the cache +> becomes authoritative for *future* investigations. + +## Straightforward Parts + +These are settled by existing ADRs and the reference implementation; Phase 1 +should document them as spec rather than re-litigate them. + +### 1. SSH is a `ProtocolHandler` on `alknet/ssh` + +Confirmed by overview.md's ALPN Registry and core-types.md. `SshAdapter` +implements `ProtocolHandler::handle(&self, connection: Connection, auth: +&AuthContext) -> Result<(), HandlerError>` with `alpn() = b"alknet/ssh"`. The +handler owns the entire `Connection` lifecycle (ADR-006: one ALPN, one +connection, one handler) and may open/accept multiple QUIC streams because it +multiplexes SSH channels. + +### 2. SSH runs over a single QUIC bidirectional stream + +The reference implementation's `transport/iroh_transport.rs` proves the +approach: open a QUIC bistream, then **join the two halves into a single duplex +type with `tokio::io::join(recv, send)`** and feed that to russh. This is the +key adapter — it is already a one-liner in tokio: + +```rust +// from alknet-main/.../iroh_transport.rs:94 +let conn = self.endpoint.connect(self.node_id, ALPN).await?; +let (send, recv) = conn.open_bi().await?; +Ok(io::join(recv, send)) // produces: AsyncRead + AsyncWrite + Unpin + Send +``` + +The Phase 0 research subagent initially speculated a custom `QuicSshStream` +adapter struct would be needed. Verifying against the reference implementation +revealed that `tokio::io::join` already produces the `AsyncRead + AsyncWrite` +combo russh requires (russh internally re-splits via `tokio::io::split`). **No +custom adapter struct is required** — the `Connection::accept_bi()` / +`open_bi()` pair plus `tokio::io::join` is sufficient. This is a meaningful +simplification over the speculative approach. + +### 3. russh accepts a generic stream on both client and server side + +Verified from `/workspace/russh/russh/src/`: + +- `server::run_stream(config: Arc, stream: R, handler: H)` where + `R: AsyncRead + AsyncWrite + Unpin + Send + 'static` — `server/mod.rs:997`. +- `client::connect_stream(config: Arc, stream: R, handler: H)` + with the same bound — `client/mod.rs:982`. + +Neither path assumes TCP — TCP-specific code (`set_nodelay`, `TcpListener`) is +confined to `run_on_socket` / `connect` / `run_on_address`. The generic stream +path is clean of TCP assumptions. russh writes its own SSH identification banner +first, then reads the peer's — no caller-side banner pre-work is needed. + +### 4. SSH channels multiplex *inside* the QUIC bistream + +`ChannelId(u32)` identifies channels; all channel traffic +(`CHANNEL_OPEN`/`DATA`/`EOF`/`CLOSE`/...) is interleaved on the single +underlying SSH transport stream that russh owns. **This is independent of +QUIC's own stream multiplexing** — one QUIC bistream ↔ one SSH connection ↔ many +SSH channels riding inside it. Port forwarding (`direct-tcpip`, +`forwarded-tcpip`) is ordinary channel traffic — each forwarded TCP connection +is a channel, not a separate QUIC stream. + +This is the cleanest mapping and the right default: alknet-ssh does not try to +map SSH channels onto QUIC streams (which would require bypassing russh's own +multiplexer). It hands russh one bistream and lets russh multiplex inside it. + +### 5. Auth routes through the shared `IdentityProvider` + +ADR-004 establishes the hybrid auth model: the endpoint resolves what it can +(TLS client cert → fingerprint), the handler resolves what it must (SSH key +fingerprint). `auth.md` shows the `SshAdapter` pattern exactly — constructor- +inject `Arc`, call `resolve_from_fingerprint()` inside +`handle()` when `auth.identity` is `None`, store the resolved `Identity` on the +`Connection` via `set_identity()` for observability (OQ-11). The +`ConfigIdentityProvider` already resolves SSH key fingerprints against +`DynamicConfig::auth::authorized_keys_fingerprints`. No new auth machinery is +needed for SSH. + +### 6. Outbound credentials (if any) come from `Capabilities` + +ADR-014 / ADR-022 establish that handlers get outbound credentials through the +registration bundle's `capabilities` field, populated by the assembly layer +from the vault. SSH itself typically needs no outbound credentials (the SSH host +key is a network-identity concern, the SSH *client* key for auth comes from the +peer), but if alknet-ssh ever needs an outbound secret (e.g., to dial an upstream +SOCKS proxy), it comes from `Capabilities`, not from env vars or vault-on-wire. + +### 7. TCP SSH is a handler concern, not an endpoint concern + +ADR-010 is explicit: "TCP is NOT an endpoint concern... the SSH handler can +listen on a TCP socket independently." This means alknet-ssh may optionally bind +a plain TCP listener (port 22-style) and accept raw SSH connections *outside* +the ALPN endpoint. The `alknet/ssh` ALPN path and the bare-TCP path can coexist; +they share the same `russh::server::Config` and the same `server::Handler` +implementation, differing only in how the stream is obtained. This is a +two-way-door additive capability — the TCP listener can be added later without +touching the ALPN path. + +## Less Straightforward Parts (Decision Points) + +These are the points where Phase 0 surfaced genuine choices that affect the +architecture. Each is tagged with a recommended door type per ADR-009. The +Architect should turn the *accepted* recommendations into ADRs, and the +*deferred* ones into open questions. + +### DP-1: Host key sourcing — vault-derived vs config-loaded vs both +*(Recommended: one-way door — needs an ADR)* + +russh's `server::Config.keys: Vec` holds the SSH host keys the +server presents during key exchange. The host key is the SSH layer's analogue +of the TLS layer's network identity — it is what the *SSH client* verifies +against `known_hosts`. Three sourcing paths exist: + +- **(a) Vault-derived**: derive an Ed25519 key from the alknet-vault seed (HD + path) and use it as the SSH host key. Aligns with the project's "everything + keys-from-seed" philosophy (ADR-020, ADR-026) and means the SSH host key is + deterministic from the mnemonic — a node restored from mnemonic gets the same + SSH host key fingerprint. +- **(b) Config-loaded**: operator provides SSH host key file path(s) in + `StaticConfig`/`DynamicConfig`. Matches how OpenSSH works + (`/etc/ssh/ssh_host_ed25519_key`). Simplest, decoupled from the vault. +- **(c) Both**: vault-derived by default, config override for operators who + bring their own keys. Mirrors the TLS identity model (ADR-027's + `TlsIdentity::RawKey` default + `X509`/`Acme` for domain-hosted). + +**Recommendation**: **(c) both**, with vault-derived as the default. This +matches the symmetry with `TlsIdentity` in endpoint.md and respects the +"fingerprint-based, keys-from-seed" identity model. The vault is local-only by +construction (ADR-025) and assembly-layer-only access (ADR-019), so the SSH host +key is derived at startup and injected into `SshAdapter::Config` the same way +TLS RawKey identity is. Operators who want stable host keys independent of the +mnemonic can supply a key file. Phase 1 should write an ADR for this (likely +ADR-028) and a corresponding OQ if the exact config-field shape is unresolved. + +### DP-2: Per-connection host key selection +*(Recommended: one-way door — needs an ADR, ties to DP-1)* + +When supporting multiple host keys (e.g., an Ed25519 default + an RSA key for +legacy clients), russh's `server::Config.keys` is a `Vec` and russh negotiates +which to use based on the client's offered algorithms. The selection is +deterministic per-russh-version but not configurable per-connection. Question: +do we need per-peer host key selection (e.g., present different host keys to +different peer networks)? Almost certainly **no** for v1 — one host key set per +node, advertised uniformly. Phase 1 should record this as the simple model and +leave per-connection selection as a future two-way-door if a use case arises. + +### DP-3: Crypto backend — `aws-lc-rs` (default) vs `ring` +*(Recommended: two-way door — decide at implementation time, but pin the choice +in an ADR if it has cross-crate consequences)* + +russh 0.60.2 requires exactly one of `aws-lc-rs` (default) or `ring` enabled; +enabling both silently picks `aws-lc-rs`. Both produce AES-GCM / ChaCha20-Poly1305. +Considerations: + +- `aws-lc-rs` is the russh default, has broader algorithm coverage, but brings + NIST build machinery (a heavier build, requires a C compiler + cmake for the + AWSLC build). +- `ring` is lighter-weight, smaller binary, simpler build. +- **Cross-crate consequence**: alknet-core already depends on `rustls-acme = + "0.12"` with `features = ["aws-lc-rs"]` (see `crates/alknet-core/Cargo.toml`), + so `aws-lc-rs` is already in the workspace's build. Choosing `ring` for russh + while alknet-core uses `aws-lc-rs` would put *both* crypto backends in the + final binary — wasteful but not incorrect. + +**Recommendation**: **default to `aws-lc-rs`** (aligns with the rest of the +workspace and avoids a duplicate crypto backend), but treat the choice as a +two-way door — it can be flipped by changing `default-features = false` on +russh. Phase 1 should note this and *not* spend an ADR on it unless the +duplicate-backend concern turns out to matter for binary size. + +### DP-4: Client side — full `russh::client` vs SSH-only-server +*(Recommended: one-way door — needs an ADR)* + +alknet-ssh as described in the README is the *SSH handler* (server side of the +`alknet/ssh` ALPN). But the reference implementation also ships a substantial +**client** (`crates/alknet-core/src/client/*`: SOCKS5 client, connect logic, +channel manager, ~1900 lines) and a **SOCKS5** implementation +(`src/socks5/*`, ~800 lines) that turns the SSH server into a SOCKS5 *proxy +endpoint* clients can dial. The README lists alknet-ssh's purpose as "SSH +handler (russh), SOCKS5, port forwarding" — so the client/proxy functionality is +intended. + +Questions: +- Does alknet-ssh own *both* the SSH server (handling `alknet/ssh` connections) + *and* the SSH/SOCKS5 *client* (for the node to dial *out* via SSH to other + hosts)? Or does the client live elsewhere? +- Is the SOCKS5 server a feature of alknet-ssh, or a separate crate? The SOCKS5 + protocol itself is independent of SSH (it just needs a byte stream), so it + could be its own reusable crate that alknet-ssh composes with. + +**Recommendation**: Phase 1 should clarify scope with an ADR. My tentative +recommendation: alknet-ssh owns the SSH *server* (the `ProtocolHandler`) plus +the SSH *client* (for outbound SSH dialing, needed for port forwarding and +SOCKS-via-SSH). SOCKS5 itself becomes a small, self-contained, reusable crate +(e.g., `alknet-socks5`) that consumes a byte stream — keeping it decoupled from +SSH matches the "stream-agnostic" philosophy and unlocks SOCKS5 reuse over +non-SSH transports. This is a real architectural choice that deserves an ADR +rather than an implicit decision. + +### DP-5: Channel-policy surface — which SSH services does alknet-ssh expose? +*(Recommended: one-way door — needs an ADR, at least the default policy)* + +russh's `server::Handler` defaults every channel-request method to reject/no-op +(or, for `auth_publickey_offered`, accept the offer through to signature +verification). alknet-ssh must decide its default channel policy: + +- **session channels** (`shell`, `exec`, `subsystem`): does alknet-ssh run a + real shell? A restricted command set? Nothing (exec-only)? This is a major + behavioral choice. The reference implementation (per overview.md's "what + stays") had a 974-line `server/handler.rs` and a 555-line + `server/channel_proxy.rs` — it clearly did substantial channel work + (proxying channels to upstream connections). +- **port forwarding** (`direct-tcpip` in, `tcpip-forward` / `forwarded-tcpip` + out): the README explicitly lists "port forwarding" as an alknet-ssh feature, + so this is in scope. But the *policy* (which destinations are allowed, whether + to restrict by ACL/scope) needs specifying. +- **PTY/X11/agent forwarding**: almost certainly disabled by default for + security; explicit opt-in. + +**Recommendation**: Phase 1 should write an ADR defining the v1 channel-policy +surface — likely "exec + port-forwarding in scope; shell/PTY/X11/agent +deferred; channel destinations gated by ACL scopes." The exact scope set is a +design choice the Architect makes with the user. + +### DP-6: Auth method coverage — publickey-only vs password/kbdint too +*(Recommended: two-way door — start publickey-only, extend later)* + +russh supports `none`, `password`, `publickey`, `keyboard-interactive`, and +OpenSSH certificate auth server-side. alknet's identity model (auth.md) is +*fingerprint-based* — SSH key fingerprint → `IdentityProvider` → `Identity`. +This maps naturally onto **publickey** (the fingerprint is the SHA-256 of the +presented public key) and **OpenSSH certificate** auth (cert fingerprint). +Password / keyboard-interactive don't fit the fingerprint model as cleanly +(there's no `resolve_from_password` on `IdentityProvider`). + +**Recommendation**: **start publickey-only** (and certificate auth, which is a +superset of publickey from the fingerprint POV). Treat password / +keyboard-interactive as a two-way door — can be added later if a use case +arises, but the natural alknet identity story is key-based. Phase 1 should note +this; likely not a full ADR (it's a default, not a structural decision) but at +least a documented design choice in the ssh spec. + +### DP-7: tokio as a hard transitive dependency +*(Recommended: acknowledged constraint, not a decision)* + +russh 0.60.2 transitively requires tokio (no "no-tokio" feature; only WASM swaps +the spawner). The server loop uses `tokio::time::sleep` for keepalive/inactivity +timers, so the tokio runtime must have its time driver enabled. **alknet-ssh +must run inside a tokio runtime** — which it will, because alknet-core's endpoint +already runs on tokio (`tokio = { version = "1", features = ["full"] }`). This +is consistent with the rest of the workspace and not a constraint to fight. +Phase 1 should record it as a known constraint; OQ-09 (WASM boundaries) already +documents that the *server-side* dispatch path is a one-way door away from WASM +— alknet-ssh inherits that. + +### DP-8: The `ssh-key` crate is forked +*(Recommended: acknowledged constraint — use the russh re-export)* + +russh 0.60.2 depends on `internal-russh-forked-ssh-key = "0.6.18"` (a renamed +fork), **not** upstream `ssh-key`. alknet-ssh must not add upstream `ssh-key` +directly — that would put two `ssh-key` versions in the tree and the +`PublicKey`/`PrivateKey` types wouldn't unify. The fork is re-exported through +`russh::keys::ssh_key`, so alknet-ssh should always reach key types via +`russh::keys::*` (or `russh::keys::ssh_key::*`) to stay on the same fork. Phase +1 should note this as an implementation constraint; it's not architecturally +interesting but a real footgun if missed. + +### DP-9: End-to-end over a non-TCP stream is untested upstream +*(Recommended: de-risk early with a POC test)* + +russh's own test suite (`/workspace/russh/russh/src/tests.rs` and +`client/test.rs`) only exercises the client↔server round trip over real TCP +loopback. There is **no** test connecting `connect_stream` ↔ `run_stream` over +`tokio::io::duplex()` or any other in-memory pipe. The `SshRead::read_ssh_id` +unit tests feed `&[u8]` directly, proving the banner parser works on +non-socket streams — but a full client↔server round trip over a non-TCP stream +is unverified upstream. + +The reference implementation uses this path in production (per +`transport/iroh_transport.rs` using `tokio::io::join`), which is strong +empirical evidence it works. But the alknet greenfield rewrite should **close +this gap early** with an integration test using `tokio::io::duplex()` connecting +`connect_stream` ↔ `run_stream` *before* going near real QUIC. + +**Recommendation**: per `sdd_process.md` Phase 0, this is a candidate for a POC +Specialist task (`.worktrees/research/ssh-stream-poc/`). Phase 1's +architecture docs should reference the POC's outcome. If the POC surfaces +issues (half-open stream handling, `poll_shutdown` semantics, etc.), they feed +back into the spec as constraints. + +## Tentative Recommended Approach (Convergence) + +Based on the above, the recommended approach to take into Phase 1: + +1. **Crate**: `alknet-ssh`, depends on `alknet-core` and `russh = "0.60"` + (default features, i.e. `aws-lc-rs`). Implements `ProtocolHandler` for + `b"alknet/ssh"`. + +2. **Stream wiring**: `handle()` accepts the QUIC `Connection`, calls + `connection.accept_bi()` once to get `(SendStream, RecvStream)`, joins them + with `tokio::io::join(recv, send)`, and hands the resulting duplex stream to + `russh::server::run_stream(Arc::clone(&config), stream, handler)`. One QUIC + bistream ↔ one SSH connection; russh multiplexes SSH channels inside it. + +3. **Auth**: constructor-injected `Arc` (per auth.md's + `SshAdapter` example). Inside `handle()`, if `auth.identity` is `None`, + russh's `server::Handler::auth_publickey` resolves the offered key's + fingerprint through the provider; on success, store the resolved `Identity` + on the `Connection` via `set_identity()` (OQ-11). Start **publickey-only** + (plus OpenSSH cert, which rides the same fingerprint path). + +4. **Host keys** (DP-1): vault-derived Ed25519 by default (derived from the + seed at startup by the assembly layer and injected into `SshAdapter`'s + config), with an optional config-supplied key file override. Symmetric with + `TlsIdentity::RawKey` (ADR-027). Needs an ADR. + +5. **Channel policy** (DP-5): v1 supports `exec` + port forwarding + (`direct-tcpip` / `forwarded-tcpip`); `shell`/PTY/X11/agent forwarding + deferred (default-reject). Forwarding destinations gated by ACL scopes on the + resolved `Identity`. Needs an ADR defining the v1 surface. + +6. **Client + SOCKS5** (DP-4): alknet-ssh also owns the SSH *client* (outbound + dialing, needed for forwarding). SOCKS5 protocol factors out into a small + reusable `alknet-socks5` crate that consumes a byte stream — decoupled from + SSH, reusable over other transports. Needs an ADR confirming the scope + split. + +7. **De-risk POC** (DP-9): a Phase 0 POC validating `connect_stream` ↔ + `run_stream` over `tokio::io::duplex()` before Phase 1 finalizes the stream + wiring spec. Strong empirical evidence from the reference implementation + suggests it will pass, but the upstream test gap is real. + +8. **TCP listener** (DP-7/ADR-010): optional, additive, deferred past v1 — the + `alknet/ssh` ALPN path is the primary surface; a bare-TCP SSH listener can be + added later sharing the same `server::Config` and `Handler`. + +## Open Questions to Carry into Phase 1 + +The following should become OQs in `docs/architecture/open-questions.md` +(numbering will be assigned by the Architect — likely OQ-25 onwards, since +OQ-01–OQ-24 exist): + +- **OQ-SSH-01 (host key sourcing)**: vault-derived default + config override — + resolved by the DP-1 ADR. +- **OQ-SSH-02 (channel policy v1 surface)**: the exact set of allowed channel + types / request types — resolved by the DP-5 ADR; some sub-questions (e.g., + default forwarding ACL) may stay open. +- **OQ-SSH-03 (client + SOCKS5 split)**: confirm alknet-ssh owns the client and + `alknet-socks5` is a separate crate — resolved by the DP-4 ADR. +- **OQ-SSH-04 (POC outcome)**: did the `duplex()`-based round-trip POC pass, and + did it surface any stream-handling constraints (half-open, `poll_shutdown`, + maximum packet size) that constrain the spec? Resolved by POC Specialist + results. +- **OQ-SSH-05 (crypto backend)**: confirm `aws-lc-rs` default aligns with the + rest of the workspace; defer flipping to `ring` unless binary-size pressure + arises. Two-way door. + +## Next Steps (Phase 0 → Phase 1) + +1. **You decide** on the DP-1, DP-4, DP-5 recommendations (or amend them) — + these are the load-bearing architectural choices. DP-3, DP-6, DP-7, DP-8 are + defaults I recommend accepting as-is; DP-9 is a POC task. +2. **Optional POC** (DP-9): spawn a POC Specialist to validate + `connect_stream` ↔ `run_stream` over `tokio::io::duplex()`. Timeboxed; if it + passes, the stream-wiring spec is straightforward; if it surfaces + constraints, they fold into the spec. +3. **Phase 1 (Architect)**: produce `docs/architecture/crates/ssh/README.md` + + component specs (e.g., `ssh-handler.md`, `ssh-stream.md`, `ssh-channels.md`, + `ssh-auth.md`), ADRs for the accepted DPs (likely ADR-028 host-key sourcing, + ADR-029 channel policy, ADR-030 ssh client + socks5 split), and the OQs above + in `open-questions.md`. Update `docs/architecture/README.md` index and + ADR table. + +## References + +- `docs/sdd_process.md` — Phase 0 process definition +- `docs/architecture/overview.md` — ALPN-as-service, crate graph, ProtocolHandler +- `docs/architecture/crates/core/core-types.md` — ProtocolHandler, Connection, BiStream +- `docs/architecture/crates/core/auth.md` — AuthContext, IdentityProvider, SshAdapter example +- `docs/architecture/decisions/001-alpn-protocol-dispatch.md` — ALPN dispatch +- `docs/architecture/decisions/002-protocol-handler-trait.md` — ProtocolHandler trait +- `docs/architecture/decisions/004-auth-as-shared-core.md` — hybrid auth +- `docs/architecture/decisions/007-bistream-type-definition.md` — BiStream trait +- `docs/architecture/decisions/010-alpn-router-and-endpoint.md` — endpoint, TCP-is-handler-concern +- `docs/architecture/decisions/014-secret-material-flow-and-capability-injection.md` — Capabilities +- `docs/architecture/decisions/022-handler-registration-provenance-and-composition-authority.md` — registration bundle +- `docs/architecture/decisions/025-vault-local-only-dispatch.md` — vault local-only +- `docs/architecture/decisions/027-tls-identity-redesign-acme-rawkey-decoupling.md` — TLS identity model (symmetry reference for DP-1) +- `docs/research/references/ssh/russh/01-06` — existing russh deep-dives +- `/workspace/russh/` — russh 0.60.2 source (authoritative; cargo cache has 0.49.2 only) +- `/workspace/@alkdev/alknet-main/crates/alknet-core/src/` — reference implementation + (`transport/iroh_transport.rs:94` shows the `tokio::io::join` adapter; `server/`, + `interface/ssh.rs`, `client/`, `socks5/` for prior art) \ No newline at end of file