Files
alknet/tasks/client/socks5-server.md
glm-5.1 5c820a41e9 tasks: decompose Phase 0a ADR foundation and mark prior tasks completed
Add 10 new tasks under tasks/architecture/ for Phase 0a (ADR writing):
- 9 ADR tasks (026-034) with dependency-ordered structure
- 1 review checkpoint task before Phase 0b spec writing

ADR dependency graph (3 generations):
  Gen 1 (parallel): 026, 029, 030, 031, 032, 034
  Gen 2 (depends on 029): 027, 028
  Gen 3 (depends on 027+028): 033
  Gen 4: review checkpoint

Also mark all 34 prior implementation tasks as completed — they
were finished but still showing as pending in the taskgraph.
2026-06-07 08:55:33 +00:00

50 lines
2.2 KiB
Markdown

---
id: client/socks5-server
name: Implement SOCKS5 server — local proxy that forwards through SSH channels
status: completed
depends_on:
- auth/client-auth-handler
- transport/trait-and-types
- auth/error-types
scope: moderate
risk: medium
impact: component
level: implementation
---
## Description
Implement the local SOCKS5 proxy server — the primary client interface (ADR-005). Listens on a local port (default `127.0.0.1:1080`), accepts SOCKS5 connections, and for each connection:
1. Reads the SOCKS5 handshake (auth method negotiation, target address)
2. Opens `channel_open_direct_tcpip(target_host, target_port, originator_addr, originator_port)` on the SSH session
3. Converts the SSH channel to a stream via `channel.into_stream()`
4. Runs `tokio::io::copy_bidirectional(&mut local_socket, &mut ssh_stream)` to proxy data
Supports SOCKS5h (domain names resolved server-side) by default. This prevents DNS leaks — the client never resolves target hostnames locally (ADR-006).
## Acceptance Criteria
- [ ] `crates/alknet-core/src/socks5/mod.rs` exports `Socks5Server`
- [ ] `Socks5Server` binds to configurable listen address (default `127.0.0.1:1080`)
- [ ] SOCKS5 handshake: method negotiation (no-auth only), target address parsing (IPv4, IPv6, domain name)
- [ ] Domain name targets (SOCKS5h) sent unresolved to server — no local DNS resolution
- [ ] For each SOCKS5 connection, opens SSH `direct_tcpip` channel and proxies bytes bidirectionally
- [ ] Connection errors (SSH session down, channel open failed) result in SOCKS5 error response to client
- [ ] No logging of SOCKS5 request targets (ADR-006) — only connection-level events logged
- [ ] SOCKS5 server always enabled when `alknet connect` runs (per client.md constraint)
- [ ] Unit tests: SOCKS5 handshake parsing, address type handling, bidirectional proxy flow (with mock transport)
## References
- docs/architecture/client.md — SOCKS5 Server section
- docs/architecture/decisions/005-socks5-before-tun.md — SOCKS5 as primary interface
- docs/architecture/decisions/006-no-logging-of-tunnel-destinations.md — no DNS leak, no logging
## Notes
> To be filled by implementation agent
## Summary
> To be filled on completion