<p align="center">
<img src="https://raw.githubusercontent.com/yukimemi/yaiba/main/assets/logo.svg" alt="yaiba — vim-flavoured todo & gantt, peer to peer" width="620">
</p>
# yaiba-sync
Peer-to-peer replication for [yaiba](https://github.com/yukimemi/yaiba)
over [iroh](https://iroh.computer) QUIC — no server in the middle.
This is the transport, not the app. Install
[`yaiba`](https://crates.io/crates/yaiba) if you want the tool.
## How it works
Every instance is a full replica and syncing is symmetric: no peer is
authoritative, and none has to be reachable at a fixed address. iroh
dials by public key and hole-punches, so peers need **outbound UDP and
nothing else** — no port forwarding, no inbound firewall rule. When hole
punching fails the connection falls back to a relay, which forwards
already-encrypted QUIC and cannot read what passes through.
Hole punching binds a UDP socket on every interface, which is what a
desktop firewall asks about on startup. `SyncNode::start_with` and
`Transport::RelayOnly` bind no UDP socket at all and let the relay carry
everything — slower, but there is no prompt to answer, and on a machine
without administrator rights there is nobody who could answer it.
One bidirectional stream carries a three-message exchange that leaves
both sides holding the union of each other's writes:
```text
dialer ──── Hello { room, vv_a } ────▶ listener
◀─── Offer { vv_b, entries } ── (what A is missing)
──── Push { entries } ───────▶ (what B is missing)
```
Both directions travel in a single round trip because each side sends
its version vector before the other has to decide what to transmit —
only the difference crosses the wire, never the whole dataset.
Membership is a shared 32-byte room key carried in the ticket. A peer
that can't present it is dropped before any data moves.
## License
MIT