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Allocate IPv4 addresses and keep them, as signed state

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Derived IPv4 addresses could not survive anything: they changed with the
range, and there was no way for a member to come back to the one it had.
Addresses are now allocated and recorded as signed facts, which is the
first slice of the model in docs/sync-model.md.

src/state/ holds one record per author per network, carrying that author's
complete current statement, signed with its persistent device key over a
length-prefixed canonical encoding. Merging follows the model's rules: a
higher version wins, an older one never rolls back a newer, duplicates are
idempotent, absence from a snapshot is not deletion, and a same-version
conflict is resolved identically on every replica and reported rather than
letting replicas diverge. Records are persisted in state.sqlite, with the
record and the author's version counter committed in one transaction
before anything is announced, and distributed as a State control message
that is merged into what the receiver already holds.

No vote, deliberately, despite the request. A majority is not a trust root
here — anyone with the secret can mint identities — and a quorum would
stall with one peer online and diverge across a partition. Signatures plus
a deterministic merge converge without either failure mode: two members
claiming one address at once are resolved by the lower endpoint id, and
the loser allocates again with a higher version.

The range moved from the plugin to the agent, defaults to 10.13.37.0/24,
and is now agreed rather than configured per member: a joining agent
adopts what the network already uses, so --ipv4-range only matters for
whoever starts it. The announcement went back to identity only (version 3)
since the range travels in signed records now.

A release tombstone exists and merges correctly, but nothing emits one
yet.

116 tests. The headline ones: an address survives restarting both agents,
three members get three distinct addresses, and a member started with a
different range adopts the one in use. Confirmed by hand with two CLI
agents restarted end to end.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
This commit is contained in:
tsunagi
2026-09-21 13:43:01 +01:00
co-authored by Claude Opus 5
parent ce64264027
commit 84c06c6cac
25 changed files with 1967 additions and 365 deletions
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README.md
+11 -23
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@@ -129,33 +129,21 @@ ping 100.65.243.53
IPv6 works out of the box: each member's address is derived from the network
id and collides with essentially nothing.
**IPv4 is opt-in**, because no IPv4 range is free on every host —
`100.64.0.0/10` is Tailscale's, `10.0.0.0/8` and `192.168.0.0/16` are
everywhere, `172.17.0.0/16` is Docker. Name one you know is unused, the same
one on every member:
**IPv4 addresses are allocated and then remembered.** The default range is
`10.13.37.0/24`; the first member to join settles it and later members adopt
what they find, so `--ipv4-range` only matters for whoever starts the network:
```bash
tsunagi up --network lab --secret "$SECRET" --wireguard --ipv4-range 10.77.0.0/16
tsunagi up --network lab --secret "$SECRET" --wireguard --ipv4-range 10.44.0.0/16
tsunagi up --network lab --secret "$SECRET" --wireguard --ipv4-range none # IPv6 only
```
The range is part of how addresses are derived, so members configured
differently would misroute. It travels in the announcement purely so a
mismatch is reported instead: the offending peer gets no IPv4 and keeps
working over IPv6. See
[docs/wireguard.md](docs/wireguard.md#ipv4-alongside-ipv6).
Notes:
- Only one side needs `--peer`; the link is bidirectional.
- The default `--transport relay` uses iroh's public address lookup and relays,
so two machines behind NAT find each other. `--transport local` keeps everything
on the local network. See *How peers find each other* below — it is worth
understanding what gets published.
- Without a network interface, add `--no-tun`: the mesh, the data links and the
WireGuard handshakes all still run and are visible in the status output, only
traffic does not reach the operating system. That is the quickest way to
confirm the network forms.
- For real traffic, see *Running unprivileged* below.
An address is claimed with a record signed by that member's persistent device
key, stored, and merged between every replica. A member that disappears for a
month comes back to the same address, because the claim outlived the session.
No vote is involved — see
[docs/wireguard.md](docs/wireguard.md#ipv4-allocated-signed-and-kept) and
[docs/sync-model.md](docs/sync-model.md).
## Running unprivileged