PR #74's Docker-Desktop fix routed the agent through
`127.0.0.1:<random>` loopback forwards, but TSI filters by IP
only — so the allowlist `127.0.0.1/32` let the agent VM reach
**any** host service on macOS loopback (postgres, dev servers,
other bottles' published ports, mDNSResponder, ...). Real
downgrade vs the docker backend's `--internal` network.
Resolution: per-bottle loopback alias.
- New `loopback_alias` module manages a pool of
`127.0.0.16` .. `127.0.0.31` on `lo0`. macOS only routes
`127.0.0.1` by default; the extras need `sudo ifconfig lo0
alias`. `ensure_pool()` lazily adds the missing entries via
one sudo prompt on first launch per reboot — aliases persist
on `lo0` until reboot, so subsequent launches skip the
prompt entirely.
- `allocate(slug)` picks the lowest-numbered unused alias by
inspecting running bundle containers' port-binding HostIps.
No on-disk reservation — docker is the source of truth.
- Bundle bringup binds published ports to the allocated alias
(`docker run -p <alias>::<port>`) instead of `127.0.0.1`.
- TSI allowlist becomes the alias's /32 — narrows reachability
to this bottle's bundle only.
- Linux native daemons share the host's network namespace;
`127.0.0.0/8` works without aliases, so the module no-ops on
non-Darwin and returns `127.0.0.1` from `allocate`.
Tracking issue closed: gitea/issues/75.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
