The motivation of this change is to move away from tying signing to be
specifically for ed25519. The reason being that the protocol will want move
towards two different kinds of signing – the node signing artifacts, and an
author signing artifacts.
This change captures the former, node signing, by introducing a `Device` type
that is the `NodeId` – a PublicKey underneath the hood – and a signing
mechanism. This allows the replacement of the `Signer` trait being used – which
always assumed a `PublicKey`. Instead, the `Device` is constructed with
`NodeId`.
In `radicle-cob`, a signer is expected to implement
`signature::Signer<ExtendedSignature>`, and everywhere in `radicle`,
`radicle-node`, `radicle-cli`, and `radicle-remote-helper` is expected the
signer is expected to implement `signature::Signer<Signature>`.
A `Device` implements both of these but only requires
`signature::Signer<Signature>` to do so – since an `ExtendedSignature` is
essentially `(PublicKey, Signature)`, and the `NodeId` of the `Device` can be
used.
We use the *staggered broadcast* technique when relaying gossip messages
to reduce message amplification. In our basic simulation, it brings
amplification down from 3.5 to 1.5.
The idea is simply to accumulate gossip messages and relay them after a fixed
interval of time. This has two effects:
1) Old messages that haven't been sent yet are replaced by newer ones,
so only one message is sent after the delay.
2) Because nodes have their own intervals, messages are not all sent at
the same time, which reduces the chance of messages crossing paths.
For now we only turn this on for inventory messages, since this is the
least likely to be noticed by users, and also the most problematic
currently.
If our inventory hasn't updated, don't issue a new inventory
announcement, simply use the previous message.
This avoids identical inventories propagating over the network and using
up resources.
Instead of having a routing database, and an addresses database,
consolidate that in a single database called `node.db`.
We also simplify database access, by providing a single type for opening
the database, and use traits to access the various functions.
We create a new `seed::Store` that has seed-related methods split out of
the `address::Store`.
Note that tracking is still in its own database currently, as it isn't
ephemeral state. This makes it easy to delete the new `node.db` without
risk of losing any important information.
To avoid renaming all database methods, we create a `Stores` wrapper
that allows us to access routing, addresses, seeds etc. without type
ambiguity.
This is a breaking change and requires `addresses.db` and `routing.db`
to be deleted.
Currently, if refs are updated while the node is stopped, these refs are
not immediately announced when the node starts, due to the node being
unaware of the updates.
To remedy this, on startup, we compare the refs we have in storage with
the refs we announced to the network. Since only our own refs could have
changed while the node was stopped, this change only applies to owned
refs. If we detect that storage has changed while the node was stopped,
we create ref announcements for the updated repos and store them in our
gossip database. These announcements will be included with other
historical gossip announcements when nodes connect to us.
To keep track of what was announced, we store our local node's sync
status in the database. This is also useful when using the `rad sync status`
command, as it tells us what oid our local node is at, and whether it
is aware of our local changes yet.
In addition to this, we make a small fix: previously, inventory and ref
announcements originating from our local node were not stored in the
announcement database. We ensure that they are via the new `announce`
method.
Previously, we would process any valid inventory or refs announcement.
This could cause problems for keeping sync statuses, as we could get
a refs announcement from a node that isn't in our database.
In practice, there is no good reason why we should receive a refs or
inventory announcement before the announcer's node announcement, unless
nodes are not following the protocol.
Implementing this change meant that many of the tests needed updating,
as it wasn't assumed that a node announcement was needed before
receiving inventories etc. from a peer.
We also had to implement a basic form of node address banning to make
the tests pass after this change.
Previously, we would always ask nodes for messages from one hour ago.
This meant that we could miss messages if our node was offline for more
than an hour. This change uses a variable backlog by checking the
timestamp of the last gossip message we received.
Instead of storing received gossip messages in an in-memory `BTreeMap`,
we persist them to the database (`addresses.db`). There are two reasons
for this:
1. Node restarts do not wipe the state, meaning that it is much less
likely that some gossip message will get lost before reaching all
nodes.
2. This will allow us in the next commit to know how far behind we are
after a restart, to be able to request the correct time range of
gossip messages that we missed while offline.
Note that we now share the addresses.db file between two connections and
stores, which we don't do anywhere else. Having multiple connections to
the same database is fine, but the way we're having to do it is a bit
awkward. In a future patch, we could pull out the database schema from the
`address` module and rename the database to make things clearer.
Lorenz Leutgeb
Fintan Halpenny
cloudhead