The previous framing ('mod 2 vs mod 3 vs mod 4 for the stream_type
space within a channel') was a symptom. The actual question is the
separation of concerns between the channels layer and the handler.
Resolution: the channels layer routes by channel_id only; handlers
own their sub-multiplexing on the BiStream they receive. Every
channel is a BiStream. The 'pass a stream to/from any ALPN' objective
becomes universal, not qualified.
The wire formats compose by construction: the 9-byte channels header
is the 5-byte TTY header with channel_id:u32 prepended. The channels
layer adds channel_id on write, strips it on read, hands the inner
5 bytes to the TTY handler. TTY's wire.rs works as-is. The
'double-chunking' objection (ADR-077's reason for rejecting
sub-multiplex inside channels) was about a 14-byte double-header; the
actual composition is 9 bytes total, shared across both layers because
the length prefix is shared.
This dissolves:
- The mod 2/3/4 question at the channels layer (the channels layer
has no stream_type concept).
- The 'control isn't actually bidirectional' TTY flaw (TTY owns its
sub-streams; stream_type 3 = ctrl_in, 4 = ctrl_out at the TTY layer).
- The 'into_sub_streams() as a second-class accessor' (removed;
accept_bi is the only accessor, yields one BiStream per channel).
- The recursive composition question (made cleaner — strip a prefix
at every level, uniform shape).
- The 'merge and split stderr' confusion (stderr is a handler concern;
the channels layer carries bytes; TTY owns the stdout/stderr
distinction).
ADR-077 is reversed: TTY always uses its 5-byte format, the channels
layer carries it transparently. The two-mode TTY design is preserved
but differs only in BiStream source, not in parsing.
No production constraint (develop branch is a rewrite, no one is
using this version yet). The decision is purely 'what's cleanest.'
One open sub-question: 8 bytes vs 9 bytes for the channels wire format.
9 bytes preserves TTY's wire.rs via literal strip/add; 8 bytes is more
uniform across inner layers but requires rewriting TTY's format.
Default assumption: 9 bytes (the strip/add property is the elegant one).
ADR-093 is ready to draft. The structural question is resolved.
Alknet
Status: Pre-alpha — This project is undergoing a major architectural pivot to an ALPN-as-service model. The previous implementation has been archived and a greenfield rebuild is in progress.
A self-hostable networking toolkit built on QUIC+TLS with ALPN-based protocol dispatch. Each protocol handler (SSH, SFTP, Git, HTTP, DNS, messaging, call protocol) registers an ALPN string on a shared endpoint. The ALPN negotiation during the TLS/QUIC handshake routes connections to the correct handler before any application bytes are read.
Core Insight
A service IS an ALPN. One endpoint, one port, many protocols — dispatched by the TLS handshake, not by application-level peeking or separate listeners.
Crates
| Crate | Status | Description |
|---|---|---|
alknet-vault |
stable | Local key vault: BIP39/SLIP-0010/AES-GCM key derivation and encryption |
alknet-core |
planned | ProtocolHandler trait, ALPN router, auth/identity, config |
alknet-ssh |
planned | SSH handler (russh), SOCKS5, port forwarding |
alknet-call |
planned | JSON-RPC call protocol (EventEnvelope framing) |
alknet-fs |
planned | Content-addressed file storage (iroh-blobs backend) |
alknet-sftp |
planned | SFTP handler (russh-sftp protocol core) |
alknet-git |
planned | Git smart protocol handler (gix) |
alknet-http |
planned | HTTP handler (axum, REST API, MCP) |
alknet-dns |
planned | DNS handler (hickory-proto, pkarr) |
alknet-msg |
planned | E2E encrypted messaging, mixnet support |
alknet |
planned | CLI binary (assembles and registers handlers) |
Documentation
- ALPN-as-service architecture — pivot proposal
- Cleanup plan — greenfield transition plan
- SDD process — spec-driven development process
- Research references — iroh, russh, russh-sftp deep dives
Reference implementation (previous architecture) is preserved at /workspace/@alkdev/alknet-main/.
License
Licensed under either of
- Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
- MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)
at your option.
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in this work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.