One agent, one interface, owned by the agent rather than by a protocol.
That is what makes several protocols able to be live at once: a packet
leaving the interface is routed to whichever peer owns its destination,
over whichever protocol has a link to that peer, and neither protocol
has to hold the address because the agent holds it.
This commit moves the pieces without changing behaviour: provisioning,
the TUN itself, IP header parsing and interface naming are now
crates/tsunagi/src/overlay, and the WireGuard module re-exports them
while its callers are moved over. They were never WireGuard-specific —
netlink, capabilities and `ip tuntap` have nothing to do with the
protocol running on top.
They also get their own error type. An interface that cannot be created
is not a plugin failing, and now that the two belong to different levels
they should not share a word for it.
Routing, addressing and the reduced plugin contract come next.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
First step of separating the layers. The library and the binary are now
crates/tsunagi and crates/tsunagi-cli, which means the plugin crate to
come can be told apart from the core by the compiler rather than by
discipline.
Falls out of it immediately: the CLI's dependencies stop being features
of the library. clap, anstream and tracing-subscriber were optional
dependencies behind a `cli` feature that every library user had to
remember to turn off; now they belong to the crate that uses them, and
the library defaults to no features at all.
The one test that drives the binary moved beside it — a library cannot
depend on a binary built from a crate that depends on the library — and
was rewritten against the public API instead of the test harness.
AGENTS.md said to prefer one crate. It now says the system level and its
plugins are separate crates, for the reason above, and that everything
else stays one crate.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
tsunagiandClaude Opus 5