alknet/docs/architecture/crates/client

status, last_updated

status	last_updated
draft	2026-07-17

alknet-client

The native client dial seam — the client-side analogue of AlknetEndpoint. A multi-transport dialer that takes pre-built transport handles (quinn, TCP+TLS, iroh), dials a remote AlknetEndpoint on a chosen ALPN, and produces a Connection for the protocol take-overs (CallClient::spawn_dispatch, ChannelClient::from_connection) to consume. It is the Rust native client; it does not run protocols, manage peer lifecycle, or supervise reconnection. It dials and produces a Connection. A client that wants to hide its real IP from the hub configures a SOCKS5 proxy (with_socks5_proxy, ADR-090) — all three dials route through it (UDP ASSOCIATE for QUIC, CONNECT for TCP+TLS, force-relay-only + HTTP-to-SOCKS5 bridge for iroh).

What

AlknetClient is the dial. Before this crate, each protocol client (CallClient::connect, ChannelClient::connect_quic) built its own QUIC dial inline — building a TlsClientConfig, constructing a quinn::Endpoint, calling connect_with, wrapping as a Connection. The dial boilerplate was duplicated, and there was no place for a second transport's dial (TCP+TLS, iroh) to live without each protocol client growing its own per-transport dial helper. Those convenience constructors are removed (see "Relationship to CallClient / ChannelClient" below); AlknetClient is the single dial home, and the protocol crates shed their TLS/transport deps entirely.

alknet-client extracts the dial the same way ADR-083 extracted the accept loop on the server side: one type that takes pre-built transport handles and produces a Connection, with the transport choice as a parameter. The protocol take-overs are unchanged — they consume the Connection and do not know AlknetClient produced it.

The three concept layers (ADR-089 §"The tangle this ADR also names")

Three concept levels were conflated throughout the initial development. AlknetClient is the fix for one of them (the establishment side); naming all three is what makes the fix legible.

Layer	Concepts	What it determines
Deployment role	Hub / Worker / Hub-Worker	Who accepts, who dials — which side(s) you instantiate
Establishment side	AlknetEndpoint (server) / AlknetClient (client)	Accept-and-resolve-identity vs. dial-and-present-identity
ALPN-level category	Endpoint ALPN / Entry-point ALPN (ADR-086 §2)	Whether identity is required at the TLS layer vs. per-request

The layers are orthogonal. A hub uses an AlknetEndpoint (server) AND an AlknetClient (client, when dialing workers). A worker uses an AlknetClient (client) AND may use an AlknetEndpoint (server, if it accepts inbound). The role determines which side(s) you instantiate, not what the side IS. AlknetClient is the client-side establishment type — Layer 2 — independent of the deployment role that uses it and of the ALPN-level category of the ALPN it dials.

What AlknetClient IS

The client-side analogue of AlknetEndpoint: a multi-transport dialer that produces Connections for the protocol take-overs to consume. Narrowed to the native case: dialing native endpoint types (QUIC + TCP+TLS, both rustls-consuming via TlsClientConfig; iroh as the key-not-config exception) over the native ALPNs (alknet/register, alknet/call, alknet/channels). With an optional SOCKS5 proxy (ADR-090), the dials route their transport through the proxy — UDP ASSOCIATE for QUIC, CONNECT for TCP+TLS, force-relay-only + HTTP-to-SOCKS5 bridge for iroh — to hide the client's real IP from the hub.

What AlknetClient is NOT

• Not a protocol implementation. It does not run the call protocol or the channels protocol. It produces a Connection; CallClient/ChannelClient take over from there. Analogue: AlknetEndpoint dispatches by ALPN; the handler runs the protocol.
• Not a hub or worker. Hub/Worker are deployment roles that use AlknetClient (and AlknetEndpoint). AlknetClient has no peer lifecycle, no aggregated env, no supervision loop, no relay. The hub's supervise_worker takes a dial closure that can call AlknetClient internally — the hub does not need to know AlknetClient exists.
• Not the web/browser client. Browsers dial via WebSocket/HTTP (ADR-044/048) — a different client surface (the JS SDK / wasm), not AlknetClient. AlknetClient is the Rust native client.
• Not a replacement for CallClient/ChannelClient. Those are the protocol take-overs. AlknetClient is the dial that feeds them.

Why

The dial was deferred (OQ-55) because extracting a QUIC-shaped connector would bake QUIC in as the establishment shape. ADR-089 resolves the deferral — three decisions (ADR-086, ADR-087, ADR-083) collapsed the blocking conditions. See ADR-089 §"Why the deferral has collapsed" for the full rationale.

Architecture

AlknetClient

The central type. Holds pre-built transport handles, all optional — the client dials with whichever transport the remote endpoint type implies.

pub struct AlknetClient {
    #[cfg(feature = "quinn")]
    quinn: Option<quinn::Endpoint>,
    #[cfg(feature = "tcp")]
    tcp_connector: Option<tokio_rustls::TlsConnector>,
    #[cfg(feature = "iroh")]
    iroh: Option<iroh::Endpoint>,
    // When set, `dial_quic` and `dial_tcp_tls` route through this
    // SOCKS5 proxy (UDP ASSOCIATE / CONNECT respectively). `dial_iroh`
    // forces relay-only via an HTTP-to-SOCKS5 bridge — see ADR-090 §5.
    // Feature-gated on `socks5`.
    #[cfg(feature = "socks5")]
    socks5: Option<Socks5ProxyConfig>,
}

impl AlknetClient {
    pub fn new() -> Self;

    #[cfg(feature = "quinn")]
    pub fn with_quinn(mut self, endpoint: quinn::Endpoint) -> Self;

    #[cfg(feature = "tcp")]
    pub fn with_tcp_tls(mut self, connector: tokio_rustls::TlsConnector) -> Self;

    #[cfg(feature = "iroh")]
    pub fn with_iroh(mut self, endpoint: iroh::Endpoint) -> Self;

    /// Set the SOCKS5 proxy for all subsequent dials. When set, every
    /// dial routes its transport through this proxy: UDP ASSOCIATE for
    /// `dial_quic`, CONNECT for `dial_tcp_tls`, and force-relay-only +
    /// HTTP-to-SOCKS5 bridge for `dial_iroh` (ADR-090 §5). Feature-gated
    /// on `socks5`.
    #[cfg(feature = "socks5")]
    pub fn with_socks5_proxy(mut self, proxy: Socks5ProxyConfig) -> Self;
}

The builder mirrors AlknetEndpoint's with_quinn / with_iroh / with_tcp_tls (ADR-083) — the assembly layer builds the transport handles and hands them to the client via builder methods. A native client that needs QUIC-with-TCP+TLS-fallback holds both a quinn endpoint and a TCP+TLS connector; a minimal iroh-only client holds only the iroh endpoint. The with_socks5_proxy builder (ADR-090) adds the privacy posture: when set, the rustls dials route through the proxy, hiding the client's real IP from the hub.

The three dials

impl AlknetClient {
    /// QUIC dial. Builds a `TlsClientConfig` from `creds`
    /// (ADR-034 verifier selection + ADR-084 provider), dials `addr`
    /// on `alpn`, returns a `Connection` via
    /// `Connection::from_quinn_with_alpn`. The `server_name` is the
    /// TLS SNI / name (for X.509; ignored for raw-key pinning).
    /// Feature-gated on `quinn`.
    #[cfg(feature = "quinn")]
    pub async fn dial_quic(
        &self,
        addr: SocketAddr,
        server_name: &str,
        alpn: &[u8],
        creds: &ConnectionCredentials,
    ) -> Result<Connection, ClientDialError>;

    /// TCP+TLS dial. Builds a `TlsClientConfig` from `creds`,
    /// connects a `TcpStream` to `addr`, wraps with `TlsConnector`
    /// using `host` as the SNI, returns a `Connection` via
    /// `Connection::from_bidi` (ADR-065). Feature-gated on `tcp`.
    #[cfg(feature = "tcp")]
    pub async fn dial_tcp_tls(
        &self,
        host: &str,
        addr: SocketAddr,
        alpn: &[u8],
        creds: &ConnectionCredentials,
    ) -> Result<Connection, ClientDialError>;

    /// Iroh dial. Dials on `alpn` via the iroh endpoint. The iroh path
    /// does NOT use `TlsClientConfig` — iroh has its own TLS (shares the
    /// `Ed25519SecretKey`, not the rustls config — ADR-087 §3, ADR-089
    /// §3). The local key is on the pre-built iroh endpoint (set when
    /// `with_iroh` configured it); the remote `NodeId` is derived from
    /// `creds.remote_identity.fingerprint` (`ed25519:<hex>` →
    /// `NodeId::from_bytes`). The verifier is iroh's `NodeId` match
    /// (fingerprint pin by another name — ADR-034 §3). An unknown iroh
    /// remote fails closed (no CA — `remote_identity` must be `Some`).
    /// Feature-gated on `iroh`.
    #[cfg(feature = "iroh")]
    pub async fn dial_iroh(
        &self,
        alpn: &[u8],
        creds: &ConnectionCredentials,
    ) -> Result<Connection, ClientDialError>;
}

The two rustls dials (dial_quic, dial_tcp_tls) share TlsClientConfig::new — the ADR-034 verifier selection (fingerprint pin for a known peer, CA-verify for an unknown X.509 remote, fail-closed for an unknown raw-key remote) and the ADR-084 crypto provider (aws_lc_rs). The iroh dial is the exception: iroh has its own TLS and takes the Ed25519SecretKey directly (on the pre-built iroh endpoint, not extracted from creds at dial time), not a rustls::ClientConfig. The consistency is in the rule (ADR-034), not in the type — the same exception as the server side (ADR-082, ADR-087 §3). All three dials take &ConnectionCredentials — the unified transport-level credential bundle (ADR-091).

What the dial does NOT do

• No protocol take-over. The dial returns a Connection; the caller hands it to CallClient::spawn_dispatch or ChannelClient::from_connection. AlknetClient does not spawn the dispatch loop or install channel 0.
• No identity resolution. The client presents its identity (via the client cert in TlsClientConfig) and verifies the remote (via the ADR-034 verifier). It does not resolve the remote's identity into a PeerId — that happens inside the protocol take-over (the CallAdapter / CallConnection resolves the fingerprint via IdentityProvider).
• No reconnection / supervision. The dial is one-shot. A caller that needs reconnect-with-backoff wraps the dial in a supervision loop (the hub's supervise_worker pattern — a closure that produces a Connection).
• No transport fallback. A caller that needs QUIC-with-TCP+TLS-fallback dials QUIC, catches the error, and dials TCP+TLS. AlknetClient provides both dials; the fallback policy is a caller concern (or a future dial_with_fallback helper — two-way-door).

SOCKS5 proxy (ADR-090)

A client that wants to hide its real IP from the hub (the primary privacy use case) configures a SOCKS5 proxy via with_socks5_proxy. When set, the rustls dials route their transport through the proxy — the hub sees the proxy's IP, not the client's. The proxy is a first-class dial capability, not a niche feature. See ADR-090 for the full rationale, the PoC grounding, and the limitations.

Dial	SOCKS5 command	Mechanism	Hides IP from
dial_quic	UDP ASSOCIATE (RFC 1928 §6)	Socks5UdpSocket (the crate's quinn::AsyncUdpSocket impl, behind socks5) → new_with_abstract_socket — see ADR-090 §3	The hub (peer)
dial_tcp_tls	CONNECT (RFC 1928 §3)	TcpStream to the proxy + SOCKS5 CONNECT handshake, then TlsConnector over the proxied stream	The hub (peer)
dial_iroh	force relay-only (HTTP CONNECT, bridged)	clear_ip_transports() + addr_filter(relay_only) + proxy_url (HTTP CONNECT via a local HTTP-to-SOCKS5 bridge) — see ADR-090 §5	The peer (via relay) + the relay (via the bridge → SOCKS5 proxy)

The proxy config:

pub struct Socks5ProxyConfig {
    /// The proxy's TCP address (where the SOCKS5 control connection
    /// connects). For UDP ASSOCIATE (the QUIC dial), the proxy replies
    /// with a UDP relay address that may differ; the dial uses that.
    pub addr: SocketAddr,
    /// Optional username/password auth (RFC 1929). None = no-auth.
    pub credentials: Option<Socks5Credentials>,
}

The config comes from Capabilities / the assembly layer (ADR-014), never from ALL_PROXY / HTTPS_PROXY env vars — the no-env-vars invariant. The config's crate location (it can live in alknet-client, alknet-core, or alknet-tls) is a two-way-door implementation detail; the shape is decided (ADR-090 §1).

The proxy is invisible above the dial. Connection, dispatch, ConnectionCredentials, TlsClientConfig, the hub's supervise_worker closure — none know a proxy is in the path. The proxy is purely an establishment concern, localized to alknet-client. A proxied QUIC connection still yields a Connection::from_quinn_with_alpn; a proxied TCP+TLS connection still yields a Connection::from_bidi. The protocol take-overs are proxy-unaware.

The no-proxy path is the zero-cost default. dial_quic and dial_tcp_tls without a configured proxy are byte-identical to ADR-089. The socks5 feature and the fast-socks5 dep are opt-in; deployments that don't use a proxy pay nothing.

Limitations (accepted, documented in ADR-090):

• ECN is lost on proxied QUIC. The SOCKS5 UDP header carries no ECN bits, so the proxied QUIC path falls back to non-ECN congestion control. A performance cost on congested links, not a correctness issue. An expected cost of the privacy choice.
• The proxy must support UDP ASSOCIATE for dial_quic. A deployment requirement — ssh -D does not work; a UDP-capable SOCKS5 daemon (dante, fast-socks5-based, etc.) is needed. The dial surfaces a clear error when the proxy lacks UDP support.
• dial_iroh forces relay-only, forgoing direct-path latency. iroh does not expose a socket-injection hook for the IP/direct transport (the quinn POC's Socks5UdpSocket does not transfer — see ADR-090 §5). With a proxy configured, the iroh endpoint is built with clear_ip_transports() + addr_filter(relay_only) + proxy_url, eliminating the direct path. The peer sees the relay's IP; the relay sees the proxy's IP (via the local HTTP-to-SOCKS5 bridge). Relay availability becomes a hard dependency — if the relay is down, the client cannot connect at all. This is the intended privacy/availability tradeoff; a caller that prefers availability over privacy for the iroh path simply does not set the proxy.
• proxy_url covers the relay WebSocket only, not pkarr/DoH. iroh's proxy_url proxies the relay WebSocket (HTTP CONNECT), not pkarr publishing or DNS-over-HTTPS (those use pkarr/hickory-resolver directly, not reqwest with a proxy). For the recommended force-relay-only configuration this is acceptable (QAD is disabled, peer-IP exposure is fully handled by the relay path). If a deployment needs pkarr/DoH proxied too, that is a separate gap (a small upstream contribution), not this ADR's scope.
• No silent fallback. When a proxy is configured and the proxy rejects the command, the dial returns ClientDialError::Proxy. The dial does not silently fall back to a direct connection — that would defeat the privacy posture the caller configured the proxy to enforce. A caller that wants "try proxy, fall back to direct" composes it: catch the error, dial on an AlknetClient without the proxy set. Because the proxy is set once on the client, this means two AlknetClient instances (one with with_socks5_proxy, one without) — see ADR-090 §6 for the rationale. The fallback policy is the caller's, not the dial's — same stance as ADR-089's "no transport fallback."

Two distinct SOCKS5 uses — do not conflate. The client-dial proxy (this section, ADR-090) is transport-layer privacy for the establishment side. The planned alknet-socks5 crate (ADR-085 scope table) is a SOCKS5 service one side offers the other over a channels data channel (alknet/socks5 ALPN) — a foundational handler, not a client-dial concern. The two compose at the SOCKS5 protocol level, not the alknet type level — see ADR-090 §"Two distinct SOCKS5 uses".

Credentials

AlknetClient's dials take a ConnectionCredentials bundle — the transport-level credential type from alknet-core (ADR-091). It carries the two dimensions every dial consumes: the local TlsIdentity (presented to the transport's identity layer) and the RemoteIdentity for verifier selection. The credentials come from Capabilities (ADR-014), never from environment variables — the no-env-vars invariant. The assembly layer derives them from the vault at startup and passes them to each dial.

ConnectionCredentials is not the call-protocol credential bundle. The call-protocol auth_token (a hub-correlated bearer for browsers and alknet/register — ADR-017 §7) is a per-request field on call.requested payloads, not a transport credential. It stays in the call-protocol layer (auth_token is a per-request payload field); the dial does not carry it. Dispatcher::resolve_identity resolves it via IdentityProvider::resolve_from_token at dispatch time; the from_call forwarding handler sets it via build_forwarded_payload. This keeps alknet-client free of call-protocol coupling. See ADR-091.

The dialable ALPNs

AlknetClient dials any ALPN the remote endpoint advertises. The native ALPNs (ADR-086):

ALPN	Category (ADR-086 §2)	Protocol take-over	Identity
alknet/register	entry point	(registration handshake — deferred, OQ-66)	None at TLS; per-request token (or open)
alknet/call	endpoint	CallClient::spawn_dispatch	Fingerprint (raw key / client cert) or bearer token (first frame)
alknet/channels	endpoint	ChannelClient::from_connection	Fingerprint or bearer token (resolved on channel 0 — ADR-072)

The dial is the same for all three — the difference is the protocol that runs on the resulting Connection. For alknet/register, the protocol is the registration handshake (deferred — see "alknet/register" below). For alknet/call and alknet/channels, the protocol is the call / channels take-over, which the caller invokes after the dial.

alknet/register

The native registration entry point, parallel to HTTP registration (OQ-58) but without the HTTP layer. A native worker that has no HTTP client dials alknet/register directly. The connection is an entry point (ADR-086 §2): accepted without an established peer identity, authenticated per-request by the registration token (or open for no-token registration). The dial produces the Connection; the registration handshake runs on it.

Two registration cases (token / no-token), both hub concerns and both optional — see ADR-089 §6 for the full description.

The alknet/register wire protocol (the handshake on the Connection — what frames the client sends, what the hub returns) ties into the call crate's ACL and the OQ-58 enrollment model. It is deferred to a dedicated ADR. This spec names the ALPN and its entry-point role; the HTTP registration endpoint (OQ-58) remains the first implementation. See OQ-66.

Relationship to CallClient / ChannelClient

The dial produces a Connection; the protocol take-overs consume it:

// Dial QUIC, take over as channels:
let conn = client.dial_quic(addr, "alknet", b"alknet/channels", &creds).await?;
let channels = ChannelClient::from_connection(conn).await?;

// Dial TCP+TLS, take over as call:
let conn = client.dial_tcp_tls("hub.example", addr, b"alknet/call", &creds).await?;
let call = CallClient::new(registry, idp).spawn_dispatch(conn);

The per-protocol QUIC convenience constructors that previously lived on CallClient / ChannelClient (connect / connect_quic) are removed. They welded the dial into the protocol crate — every CallClient user transitively pulled quinn + rustls + the TLS verifier machinery, and the convenience constructor's existence made alknet-call / alknet-channels-call depend on alknet-client (or duplicate the dial), contradicting the dep graph below. The dial is a distinct concern from the protocol take-over; AlknetClient is the single home for it. A caller that wants the old one-liner shape composes two lines: client.dial_quic(...).await? then CallClient::new(...).spawn_dispatch(conn) (or ChannelClient::from_connection(conn).await?). See ADR-089 §5.

Iroh — shares the key, not the config (client side too)

The iroh client dial, like the iroh server side (ADR-082, ADR-087 §3), does not consume a rustls::ClientConfig. The Ed25519SecretKey is set on the pre-built iroh endpoint at with_iroh time (the assembly layer reads it from StaticConfig and feeds it to iroh::Endpoint::builder().secret_key()). The dial_iroh method consumes only creds.remote_identity (deriving the remote NodeId); the local key is not in ConnectionCredentials for the iroh path — it is on the endpoint. The dial signature is unified — all three dials take &ConnectionCredentials (ADR-091) — and the iroh dial simply ignores the tls_identity field (the key is already on the endpoint). The verifier is iroh's NodeId match — the remote's NodeId (Ed25519 public key) is verified against the expected NodeId, which is fingerprint-pinning by another name. An unknown iroh remote fails closed (no CA to fall back to — ADR-034 §3, Assumption 1).

Non-Rust native clients (out of scope)

The wire protocols (channels 9-byte chunk format — ADR-071; call EventEnvelope — ADR-012/064) are language-agnostic. When the endpoint uses X.509 (the web endpoint type, or a native endpoint with X.509 instead of raw keys), non-Rust native clients (Node/Deno/Bun, Python, wasm) can negotiate TLS with standard library TLS stacks and implement the wire protocols directly. A wasm implementation of the wire protocols is reusable both in-browser and server-side (Deno, etc.), reducing the need for per-language native adapters.

AlknetClient is the Rust native client — one of several possible native clients sharing the same wire protocols. The non-Rust clients are out of scope for this crate; they implement the wire protocols in their own languages. The X.509 endpoint type is what makes this possible — raw-key (RFC 7250) endpoints require a TLS stack that supports raw public keys, which most non-Rust runtimes do not (browsers definitely do not — ADR-086).

ClientDialError

The error type for all three dial methods. A single #[non_exhaustive] enum, one variant per failure category:

#[derive(Debug, thiserror::Error)]
#[non_exhaustive]
pub enum ClientDialError {
    /// TLS config construction (TlsClientConfig::new failure —
    /// verifier build, cert load, provider init). Wraps `TlsError`
    /// from alknet-tls.
    #[error("TLS config construction: {0}")]
    TlsConfig(#[from] alknet_tls::TlsError),

    /// Transport connect failure — quinn connect, TcpStream::connect,
    /// or iroh connect. The transport's own error type, stringified.
    #[error("transport connect: {0}")]
    Connect(String),

    /// TLS handshake failure — the handshake started but failed
    /// (rejected cert, ALPN mismatch, unknown raw-key remote
    /// fail-closed). Distinct from TlsConfig (which is pre-handshake).
    #[error("TLS handshake: {0}")]
    Handshake(String),

    /// No transport handle configured for the requested dial — e.g.,
    /// `dial_quic` called but `with_quinn` was not set.
    #[error("no transport handle configured for {transport}")]
    NoTransport { transport: &'static str },

    /// SOCKS5 proxy failure — handshake rejected, UDP ASSOCIATE
    /// unsupported, auth failed, or the proxy closed the control
    /// connection (ADR-090). The dial did not reach the remote; the
    /// caller decides whether to fall back to a direct dial or
    /// surface the error. The dial never silently falls back — that
    /// would defeat the privacy posture.
    #[cfg(feature = "socks5")]
    #[error("SOCKS5 proxy: {0}")]
    Proxy(String),
}

TlsConfig wraps alknet_tls::TlsError (ADR-088) — the config construction errors. Connect and Handshake are transport-level failures (pre- and post-handshake). NoTransport is a wiring error (calling a dial without the matching with_*). Proxy (ADR-090) is the SOCKS5 proxy failure category — the dial's transport never reached the remote because the proxy rejected or dropped the association.

Handshake resolves an ADR-088 §6 deferral. ADR-088 §6 explicitly scoped TlsError to config-construction errors and deferred the handshake-error surfacing question to "the dial-seam ADR" (OQ-55, then deferred). ADR-089 is that ADR. ClientDialError::Handshake is the resolution: handshake-time errors (rejected cert, ALPN mismatch, unknown-raw-key fail-closed) surface through the dial's error type as Handshake(String), not through TlsError (which stays config-construction-only). This keeps ADR-088's scope boundary intact while giving the dial a single error enum for all failure categories.

Connect(String) and Handshake(String) take String rather than wrapping the concrete transport error types (quinn::ConnectError, io::Error, rustls::Error) because the three transports' error types are non-unifiable — the dial is transport-polymorphic, and there is no single source type that covers quinn, tokio-rustls, and iroh. The category is in the variant (Connect vs Handshake); the detail is in the string. This differs from ADR-088's TlsError (which wraps concrete types via #[from]) because TlsError has one source crate (rustls + pemfile + rcgen), while ClientDialError spans three transport crates. The variant granularity is decided; the exact string contents are an implementation detail.

Feature gates

[features]
default = []
quinn = ["dep:quinn", "alknet-tls/quinn", "alknet-core/quinn"]
tcp = ["dep:tokio-rustls", "alknet-tls/tcp"]
iroh = ["dep:iroh", "alknet-core/iroh"]
socks5 = ["dep:fast-socks5"]   # enables the proxied dial paths (ADR-090)

A deployment that dials QUIC only enables quinn. A deployment that dials TCP+TLS enables tcp. A deployment that dials iroh enables iroh. A full native client (QUIC + TCP+TLS fallback + iroh) enables all three. The quinn and tcp features pull the corresponding features on alknet-tls (for TlsClientConfig::for_quinn / for_tcp_tls). The quinn and iroh features also pull the corresponding features on alknet-core — dial_quic produces a Connection via Connection::from_quinn_with_alpn and dial_iroh via Connection::from_iroh, both of which live in alknet-core's types.rs behind core's quinn / iroh features (the "quinn feature split" from ADR-083 §"The quinn feature split"). The iroh feature does not pull alknet-tls features — iroh has its own TLS. The socks5 feature (ADR-090) is independent of the transport features — it enables the proxy code path that dial_quic (UDP ASSOCIATE) and dial_tcp_tls (CONNECT) use when a proxy is configured. Enabling socks5 without quinn or tcp is a no-op; enabling quinn + socks5 enables proxied QUIC; tcp + socks5 enables proxied TCP+TLS. The fast-socks5 dep is behind socks5, so deployments that don't use a proxy don't pay the dep.

Dependencies

alknet-client
├── alknet-core       (Connection, ConnectionCredentials, RemoteIdentity,
│                     Ed25519SecretKey, types)
├── alknet-tls        (TlsClientConfig — for quinn + tcp dials)
├── quinn             (optional — dial_quic)
├── tokio-rustls      (optional — dial_tcp_tls)
├── tokio             (TcpStream, spawn)
├── iroh              (optional — dial_iroh)
├── fast-socks5       (optional — SOCKS5 client, `socks5` feature — ADR-090)
└── thiserror         (ClientDialError)

alknet-client depends on alknet-tls (for TlsClientConfig) and alknet-core (for Connection, ConnectionCredentials, RemoteIdentity, and types). It does not depend on alknet-call or alknet-channels-call — the dial is below the protocol. ConnectionCredentials and RemoteIdentity live in alknet-core (transport-level credential types, moved from alknet-call per ADR-091 — the dial and the server-side transport construction both consume them, and the dial must not depend on the call protocol for the credential type). FingerprintPinVerifier lives in alknet-tls (moved from alknet-call per ADR-087 §5 — it is a TLS concern, and TlsClientConfig::new constructs it; moving it lets alknet-call shed its direct rustls dep entirely).

Crate dependencies (in the dep graph)

alknet-client
├── alknet-tls (TlsClientConfig)
│   └── alknet-core
└── alknet-core (Connection, types)

alknet-hub (uses AlknetClient for outbound worker dials)
├── alknet-client (the dial — the hub's dial_worker closure calls it)
├── alknet-channels-call (ChannelClient — the take-over)
├── alknet-call (CallAdapter, Dispatcher)
└── alknet-endpoint (AlknetEndpoint)

alknet-worker (uses AlknetClient to dial a hub)
├── alknet-client (the dial)
├── alknet-channels-call (ChannelClient — the take-over)
└── alknet-core (AlknetEndpoint — if the worker accepts inbound)

alknet-call and alknet-channels-call do not depend on alknet-client. Their take-over APIs (spawn_dispatch, from_connection) consume a Connection from any source — AlknetClient is one producer, but a test can hand them a Connection::from_stream directly. The dependency direction is: alknet-client → alknet-tls → alknet-core; the protocol crates are parallel, not downstream of the dial. ConnectionCredentials and RemoteIdentity live in alknet-core (not alknet-call), so the dial does not depend on the call protocol for the credential type.

Assembly layer integration

A downstream worker or hub uses alknet-client like this:

// 1. Build the transport handles (assembly layer — same pattern as
//    the server side's AlknetEndpoint builder).
let quinn_endpoint = quinn::Endpoint::client("0.0.0.0:0".parse()?)?;

// 2. Build the AlknetClient with the transport handles it needs.
//    Optionally set a SOCKS5 proxy (ADR-090) to hide the client's real
//    IP from the hub — all rustls dials route through it.
let client = AlknetClient::new()
    .with_quinn(quinn_endpoint)
    .with_socks5_proxy(Socks5ProxyConfig {
        addr: "127.0.0.1:1080".parse()?,
        credentials: None,  // no-auth; or Some(Socks5Credentials { ... })
    });
    // .with_tcp_tls(tls_connector) — if TCP+TLS fallback is needed
    // .with_iroh(iroh_endpoint)   — if iroh is needed

// 3. Derive credentials from the vault (ADR-014 — no env vars).
let creds = ConnectionCredentials::new()
    .with_tls_identity(TlsIdentity::RawKey(local_key))
    .with_remote_identity(RemoteIdentity {
        fingerprint: hub_fingerprint,  // known peer → fingerprint pin
    });

// 4. Dial the hub on alknet/channels, take over as channels.
//    The proxy (if set) is applied transparently by dial_quic —
//    UDP ASSOCIATE for QUIC. The Connection, the channels take-over,
//    and the credentials are all proxy-unaware.
let conn = client
    .dial_quic(hub_addr, "alknet", b"alknet/channels", &creds)
    .await?;
let channels = ChannelClient::from_connection(conn).await?;

// 5. Discover the hub's operations via from_call on channel 0.
let bundles = from_call(channels.call(), FromCallConfig::new()).await?;
channels.register_imported_all(bundles);

The hub's supervise_worker (hub README §"Dial") takes a dial closure that produces a Connection. That closure can call client.dial_quic(...) internally — the hub does not need to know AlknetClient exists. The closure seam is preserved; AlknetClient is the recommended dial producer for it.

Design Decisions

All design decisions are documented as ADRs in decisions/.

ADR	Decision	Summary
089	AlknetClient — native client dial seam	New crate alknet-client; client-side analogue of AlknetEndpoint; three dials (QUIC + TCP+TLS via TlsClientConfig, iroh via key); resolves OQ-55; alknet/register named, wire protocol deferred (§3/§5 amended by ADR-091 — dial takes ConnectionCredentials, not CallCredentials)
090	Client-Dial SOCKS5 Proxy Seam	AlknetClient gains with_socks5_proxy; dial_quic routes via UDP ASSOCIATE, dial_tcp_tls via CONNECT, dial_iroh forces relay-only via an HTTP-to-SOCKS5 bridge; OQ-67 resolved; grounded in the quinn-proxy + iroh-proxy PoCs
091	ConnectionCredentials — decouple dial from call protocol	The dial credential bundle is ConnectionCredentials (transport-level: tls_identity + remote_identity), not CallCredentials (call-protocol-level); all three dial signatures unify on &ConnectionCredentials; dial_iroh's node_id derived from remote_identity; auth_token is a per-request payload field; CallCredentials removed per Am. 2026-07-17

Open Questions

See open-questions.md for full details.

• OQ-55 (resolved by ADR-089): AlknetClient native dial seam — the transport-polymorphic dial is extracted. The deferral's blocking condition (a second transport's real dial) is met within the native endpoint type (QUIC + TCP+TLS + iroh). The web/browser client (WebSocket, HTTP) was never in scope. See ADR-089.
• OQ-66 (deferred(scope)): alknet/register wire protocol — the native registration handshake (token / no-token, the frames, PeerEntry creation, session credential return). Named as a dialable ALPN by ADR-089; the wire protocol ties into the call crate's ACL and OQ-58 (the token model is the shared blocker) and needs a dedicated ADR. The HTTP registration endpoint (OQ-58) remains the first implementation.
• OQ-67 (resolved by ADR-090 §5 amendment): iroh proxy support — dial_iroh with a proxy configured forces relay-only via three stable public iroh Builder knobs (clear_ip_transports() + addr_filter(relay_only) + proxy_url), with a local HTTP-to-SOCKS5 bridge adapting the SOCKS5 proxy to iroh's HTTP CONNECT expectation. iroh does not expose a socket-injection hook for the IP/direct transport (the quinn POC's Socks5UdpSocket does not transfer), so force-relay-only is the conservative default — no fork, fully closes the peer-IP-exposure gap by eliminating the direct path. Grounded in the iroh-proxy POC. See OQ-67.

References

• ADR-089 — the decision this spec implements (§3/§5 amended by ADR-091)
• ADR-091 — ConnectionCredentials (the dial credential bundle; decouples the dial from the call protocol)
• ADR-090 — the SOCKS5 proxy seam (client-dial privacy)
• ADR-083 — AlknetEndpoint (the server-side shape this spec mirrors)
• ADR-086 — endpoint types (native = QUIC + TCP+TLS + iroh); entry-point vs. endpoint ALPN distinction
• ADR-087 — TlsClientConfig (the prerequisite the dial consumes)
• ADR-082 — TlsServerConfig / TlsClientConfig in alknet-tls
• ADR-065 — Connection::from_stream / from_bidi (the Connection constructors the dials use)
• ADR-034 — client-side verifier selection (fingerprint pin vs CA vs fail-closed)
• ADR-084 — aws-lc-rs crypto provider
• ADR-080 — ChannelClient::from_connection (the take-over the dial feeds)
• ADR-017 — CallClient::spawn_dispatch (the take-over the dial feeds)
• docs/research/quinn-quic-proxy/findings.md — the quinn-over-SOCKS5 PoC findings (grounds ADR-090's QUIC path)
• docs/research/iroh-proxy-poc/findings.md — the iroh-proxy PoC findings (grounds ADR-090 §5's iroh force-relay-only decision + HTTP-to-SOCKS5 bridge)
• crates/endpoint/README.md — AlknetEndpoint (the server-side complement)
• crates/tls/README.md — TlsClientConfig
• crates/call/client-and-adapters.md — CallClient (the protocol take-over)
• crates/channels/channel-client.md — ChannelClient (the protocol take-over)
• crates/hub/README.md §"Dial (outbound workers)" — the hub-as-client case (the supervise_worker closure that calls the dial)
• OQ-55 (resolved) — AlknetClient / client establishment extraction
• OQ-58 — worker registration flow (the HTTP path; alknet/register is the native analogue)
• OQ-66 (deferred) — alknet/register wire protocol