UltradesuandClaude Opus 4.8
c3a6201ee2
macOS was TUN-less: the agent ran only with `--no-tun`, so tunnels formed but nothing reached the operating system. The provisioner, host rules and DNS publisher had Linux and Windows implementations and fell through to the unsupported/erroring paths on macOS. This adds the macOS half so `tsunagi up` carries real traffic there. The shared decision logic (plan_changes, rules_summary, Published) is untouched — only the per-platform mechanics are new. What it does on macOS (all root-only; macOS has no per-capability grant): - Interface: a `utun` device opened over the in-kernel utun control socket via the existing `tun` dependency (no kext, no Network Extension). The kernel assigns the `utunN` name, so a name derived from the network id is not a legal utun name; `open_tun` leaves the name unset on macOS and reads the real one back, and `Interface::start` adopts `device.name()` as the name everything downstream configures (host rules, reconfigure). A utun is torn down with the process, so a crash never leaks one. Addresses, MTU, up and the overlay subnet route are applied with `/sbin/ifconfig` and `/sbin/route` (absolute paths, args built only from locally-derived values), the same role netlink plays on Linux and netsh on Windows. Observation is `netdev` (getifaddrs). - DNS: a resolver-dir publisher writes `/etc/resolver/<network>` files pointing the system resolver at the overlay DNS server for each zone. The files carry a `port`, so the server needs no privileged socket, and a marker line, so the publisher only ever replaces or removes files it wrote and never clobbers a user's own. Removed on revert. - Broadcast host rules: the `255.255.255.255` route is installed with `route`. The inbound-UDP firewall allowance (a pf anchor) is deferred and reported as the incomplete half, so `status` says what to allow by hand; the route still goes in. Failure stays contained, exactly as on the other platforms. - Privilege: probe is optimistic (like Windows); the honest answer comes from the utun open, whose permission error now says to run with sudo or as a daemon. Deployment: - Default paths on macOS are fixed system locations rather than per-user Library dirs, so they do not depend on whose shell ran sudo: state `/var/db/tsunagi`, cache `/var/db/tsunagi/cache` (StoragePaths::user_default), control socket `/var/run/tsunagi/agent.sock` (default_control_socket_path, mirroring the Windows %ProgramData% branch). The local control socket already uses the shared `unix` adapter, so no IPC changes were needed — macOS is Unix. - dist/macos/ carries a root LaunchDaemon plist and install notes; README's deployment section now documents the macOS path instead of "not implemented". Decisions (agreed up front): utun auto-assign with the real name adopted; ifconfig/route rather than raw PF_ROUTE/ioctl (which would need unsafe); /etc/resolver files rather than scutil; route-now/firewall-deferred; root via sudo or a LaunchDaemon rather than Network Extension (which would require a signed sandboxed app bundle, not a Rust CLI). Checks: on macOS (Darwin 27), `cargo fmt --all --check`, `cargo clippy --locked --workspace --all-targets -D warnings`, and `cargo test --locked --workspace --all-targets` all pass (0 failures); the new macos-gated unit tests run under the standard workspace command via feature unification. Not yet exercised live: actual utun creation, ifconfig/route application and /etc/resolver writes need a root run, which has not been done in this session. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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Running tsunagi on macOS
The agent needs root on macOS: creating a utun interface and writing
/etc/resolver are both root-only, and macOS has no per-capability grant like
Linux. There are two ways to run it.
Quick start — sudo
sudo tsunagi up
In another terminal, the control commands talk to it over the system control
socket and do not need sudo:
tsunagi status
tsunagi join <network-name> <tsn1…secret>
The agent uses fixed system paths, so the commands find it regardless of whose
shell started sudo:
| what | path |
|---|---|
| mandatory state | /var/db/tsunagi |
| disposable cache | /var/db/tsunagi/cache |
| control socket | /var/run/tsunagi/agent.sock |
Native deployment — root LaunchDaemon
For an always-on agent that starts at boot, install the bundled
cy.hexor.tsunagi.plist.
# Put the binary where the plist expects it (edit the plist for another path).
sudo install -m 0755 target/release/tsunagi /usr/local/bin/tsunagi
# Install the daemon. launchd refuses a daemon plist that is not owned by
# root:wheel or that is group/world-writable.
sudo install -m 0644 -o root -g wheel \
dist/macos/cy.hexor.tsunagi.plist \
/Library/LaunchDaemons/cy.hexor.tsunagi.plist
# Load and start it.
sudo launchctl bootstrap system /Library/LaunchDaemons/cy.hexor.tsunagi.plist
sudo launchctl enable system/cy.hexor.tsunagi
Manage it afterwards with:
sudo launchctl kickstart -k system/cy.hexor.tsunagi # restart
sudo launchctl bootout system/cy.hexor.tsunagi # stop and unload
tail -f /var/log/tsunagi.log # logs
The control commands (status, join, network, dns) work the same against
the daemon as against a sudo tsunagi up, over the same socket.
What the agent does to the system
Everything it installs is tagged to its own interface, computed from local state, and reversible — it is removed when a network leaves, broadcast is turned off, or the agent stops:
- a
utuninterface, configured withifconfig(addresses, MTU, up) and a subnetroutefor the overlay range. The kernel assigns theutunNname; the agent adopts whatever it is given. Autunis torn down with the process, so a crash never leaves one behind. /etc/resolver/<network>files pointing the system resolver at the overlay DNS server for each network's zone, with aportso the server stays off 53. Each file carries a marker line; the agent only ever replaces or removes files it wrote, never one you created by hand.- while broadcast is on, a
255.255.255.255route through the overlay interface. The matching inbound-UDP firewall allowance is not implemented yet (it needs apfanchor);tsunagi statusreports that half as incomplete and names what to allow by hand if your host firewall drops discovery replies.
Nothing taken from a remote peer ever becomes a path, a command argument or an OS setting: the interface name comes from the kernel, addresses and ranges from signed state the agent already verified.