glm-5.1
596c89ce24
Rename all crates, CLI commands, constants, type names, doc comments, and documentation from wraith to alknet. Includes wire-protocol changes: ALPN wraith-ssh -> alknet-ssh, reserved destination prefix wraith- -> alknet-, SSH auth username wraith -> alknet.
39 lines
1.9 KiB
Markdown
39 lines
1.9 KiB
Markdown
# ADR-005: SOCKS5 as Primary Interface, TUN as Add-on
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## Status
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Accepted
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## Context
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A "VPN-like" tool needs to route traffic. There are three approaches:
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1. **TUN only**: Create a TUN interface, route all OS traffic through it. Full VPN experience but requires root.
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2. **SOCKS5 only**: Local SOCKS5 proxy. Applications configure proxy settings. No root needed but application support varies.
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3. **SOCKS5 primary, TUN add-on**: SOCKS5 is the core interface. TUN forwards to SOCKS5.
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## Decision
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SOCKS5 is the primary interface. TUN is a separate process that forwards to SOCKS5 (Option 3).
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SOCKS5 is the core because:
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- It requires no privileges
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- `curl --socks5-hostname` works everywhere
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- Browsers, most CLI tools, and many applications support SOCKS5
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- SOCKS5h prevents DNS leaks by resolving names server-side
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- It's the interface that the NAPI wrapper and pubsub adapter build on
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- TUN is only needed for "route all traffic" use cases, which are a subset of users
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TUN forwards to SOCKS5 rather than directly to SSH because:
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- The SOCKS5 code already handles TCP connection establishment and bidirectional proxying
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- TUN's job is just IP packet → SOCKS5 connection, not IP packet → SSH channel
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- The `alknet-tun` binary stays minimal (~200-500 lines)
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- No root code in the core binary
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## Consequences
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- **Positive**: Core binary is root-free. TUN functionality is provided by the external `tun2proxy` tool (ADR-014).
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- **Positive**: SOCKS5 is testable without TUN — just `curl` against it.
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- **Positive**: The TUN approach is validated by tun2proxy, a well-tested existing tool. No custom TUN code to maintain.
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- **Negative**: VPN-like behavior requires running `tun2proxy` alongside `alknet connect` — two processes instead of one integrated binary.
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- **Negative**: SOCKS5 doesn't capture UDP (except DNS via SOCKS5h). TUN mode via tun2proxy handles this separately.
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## References
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- [client.md](../client.md)
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- [tun-shim.md](../tun-shim.md) |