From c9c7807bf0f068474ce5c853244bcb392bdfcce3 Mon Sep 17 00:00:00 2001 From: tv Date: Sun, 8 Nov 2026 19:16:10 +0000 Subject: roots: an epoch's root pinned, and named in every handshake Review 2, N7, the care it raised: a joining node's empty document took as the first epoch's root whatever dependency-less change came first, from whichever peer it joined through; the first epoch's ID is all zeros, so nothing pinned it. A remake's epoch has its ID, the snapshot change's hash, which the rules hold its root to. * Every node names its epoch's root in HELLO and HELLO_REPLY (the epoch's ID for a remake's, its genesis change for the first; wire version 45). A node whose document starts from another root of the same epoch refuses the handshake, logging it: another history under the swarm's ID, a forged root or a genesis started again. * A joining node with an empty document takes as its root only the one it was given (--genesis-root, new), else the one its peers name, and none while they name different ones (access::screen::RootPin, kept in Screening across documents): one peer hands it another root only if it is all the joiner hears, or never, with --genesis-root. A root refused is listed with the refused, what builds on it with it. * The genesis node logs the root (`The swarm's root`); GET /admin/epochs shows it (`root`). A genesis started again under a remembered swarm ID used to merge with the nodes of it still running; they now refuse it (another root), and the docs say to join them with seeds instead. The epoch's identity stays as it is (generation 0 all zeros): records and epoch metadata name it so, and every comparison of epochs with them. --- src/swarm/bootstrap.rs | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) (limited to 'src/swarm/bootstrap.rs') diff --git a/src/swarm/bootstrap.rs b/src/swarm/bootstrap.rs index 98e273a..4384edb 100644 --- a/src/swarm/bootstrap.rs +++ b/src/swarm/bootstrap.rs @@ -70,13 +70,14 @@ pub(crate) async fn bootstrap(state: &AppState, seeds: &[String], start: Start) return Ok(()); } if start == Start::Genesis { - // A remembered swarm starts again under its ID: nodes of it still running then - // merge with this one instead of ending up in another swarm. + // A remembered swarm starts again under its ID, from a root of its own: nodes of + // it still running hold another, and refuse it (`swarm::roots`); joining them + // takes seeds instead. let swarm_id = match state.swarm_id().await { Some(remembered) => { warn!( swarm_id = %remembered, - "--genesis with a remembered swarm: starting it again, empty; nodes of it still running merge with this one" + "--genesis with a remembered swarm: starting it again, empty, from a new root; nodes of it still running refuse it (another root): give seeds to join them instead" ); remembered } @@ -131,6 +132,9 @@ pub(crate) async fn bootstrap(state: &AppState, seeds: &[String], start: Start) .context( "Recording the swarm ID, its neighbours, its topology and dissemination, its first users", )?; + if let Some(root) = crate::swarm::roots::own(state).await { + info!(root = %root, "The swarm's root: a node joining may be given it (--genesis-root), to take no other"); + } state.initial_sync_done.store(true, Ordering::Release); state.mark_ready(swarm_id).await?; // Remembered members, if any, to find those still running. -- cgit v1.3.1