alknet/tasks/server/channel-proxy.md

id, name, status, depends_on, scope, risk, impact, level

id	name	status	depends_on	scope	risk	impact	level
server/channel-proxy	Implement server channel proxy — direct TCP and outbound proxy connections	pending	server/handler auth/error-types	moderate	medium	component	implementation

Description

Implement the server's channel proxy logic that makes outbound TCP connections on behalf of SSH clients. When channel_open_direct_tcpip(host, port) is called for a non-reserved destination:

1. Connect to host:port, either directly or via the configured outbound proxy
2. Run tokio::io::copy_bidirectional between the SSH channel stream and the outbound TCP stream
3. Clean up when either side disconnects

Supports three outbound proxy modes per server.md: Direct, SOCKS5 proxy, HTTP CONNECT proxy.

Acceptance Criteria

• crates/wraith-core/src/server/channel_proxy.rs exports channel proxy functions
• ProxyConfig enum: Direct, Socks5 { addr: SocketAddr }, HttpConnect { addr: SocketAddr }
• connect_outbound(target: SocketAddr, proxy: &ProxyConfig) -> Result<TcpStream> — connects to target directly or via proxy
• Direct mode: TcpStream::connect(target)
• SOCKS5 proxy: establishes SOCKS5 handshake, sends CONNECT command for target
• HTTP CONNECT proxy: sends CONNECT host:port HTTP/1.1 to proxy, reads 200 response
• proxy_channel(channel: ChannelStream, target: SocketAddr, proxy: &ProxyConfig) — spawns bidirectional copy task
• Channel errors (target unreachable, proxy failure) close that channel without affecting SSH session
• No logging of tunnel destinations (ADR-006) — only transport/auth events are logged
• Unit tests: direct connection proxy, SOCKS5 proxy handshake, HTTP CONNECT proxy handshake, target unreachable handling

References

• docs/architecture/server.md — Channel Handling, Outbound Proxy Modes sections
• docs/architecture/decisions/006-no-logging-of-tunnel-destinations.md — no destination logging
• docs/architecture/decisions/019-proxy-dual-semantics.md — server --proxy meaning

Notes

To be filled by implementation agent

Summary

To be filled on completion