This introduces rate limits for the `ChannelReader` to limit DDoS attacks and
attempts to upload repositories that are larger than a node is will to permit.
The limiter sets the total number of bytes it is will to accept in a single
exchange, defaulting to 500MB. This means that initial fetches will prevent
large repositories, but is plenty for new packfile data to be sent in subsequent
fetch exchanges.
The limit can be configured within the node's config file, under the limits.
When deciding whether or not to fetch a repo based on a refs
announcement, we need to know whether our signed refs are stale or not,
compared to the ones in the announcement. This can be quite expensive as
it requires multiple reads from Git's ODB, which often results in
packfile loading.
To remedy this, we introduce a refs cache in our node database that is
consulted when an announcement is received.
We also remove the logic that generates `info` messages, since they are
rarely needed and introduced more complexity.
Additionally, we revert commit 3ad2b4431f,
which introduced logic to minimze wants and haves with additional logic,
since it potentially also increases the load on the ODB.
This change limits the amount of `wants` and `haves` data that is sent
to the serving side of a fetch.
When a `RefsAt` announcement is sent, the fetching peer can calculate
the difference between the `rad/sigrefs` they're aware of -- if it
exists -- and the newly advertised `rad/sigrefs`. This means they can
efficiently ask for the `wants` and `haves` of references that have
changed -- saving some data sent over to the serving side.
Signed-off-by: Fintan Halpenny <fintan.halpenny@gmail.com>
X-Clacks-Overhead: GNU Terry Pratchett
Announcement are logged at the debug level and are very frequent. This
causes a lot of noisy logging in a node.
Downgrade the log levels for these messages from debug to trace.
Signed-off-by: Fintan Halpenny <fintan.halpenny@gmail.com>
X-Clacks-Overhead: GNU Terry Pratchett
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.
The previous system allowed the same RID to be fetched from multiple
nodes concurrently, which caused issues, especially when cloning.
Worker code assumes that there is only one fetch per repository going on
at any given time. This change ensures that.
We keep a global fetch queue, instead of having a queue per session. We
also enqueue fetches if a session is at capacity. Finally, we allow
multiple fetch requests to receive results for the same fetch.
Ref announcements contain the namespace (NID) and the SHA of the new
`rad/sigrefs`. This information can be used by the fetch protocol to
fetch only those `Oid`s for those namespaces.
Add a new stage `SigrefsAnnouncement` that captures this behaviour by
only asking for the advertised `Oid`s and updating the corresponding
`rad/sigrefs` for each namespace. Note that this is a special case of
the `SpecialRefs` stage and so the protocol chooses between these two
by checking if there was announcement passed through. The following
stage, `DataRefs`, stays the same.
Note that this stage can only be activated via a `pull`, and `clone`
stays the same.
Signed-off-by: Fintan Halpenny <fintan.halpenny@gmail.com>
X-Clacks-Overhead: GNU Terry Pratchett
The RefsAnnouncement previous announced its complete set of
`rad/sigrefs`. This was useful in that verification can occur on the
receiveing side immediately by verifying the refs and proceeding with
the fetch -- note that it did nothing with the ref information it
received.
This can be minimised to only advertising the namespace, i.e. the
NID, and the new SHA of the `rad/sigrefs`. This is represented by a
new message type, `RefsAt`, which contains the NID and the Oid.
For checking if an announcement is stale or fresh, the receiving
side can check the existence of the SHA in its Git repository.
The tests are appropriately modified to use NIDs and Oids.
To prepare for a follow-up change, the announcement data is also
threaded through for the fetch protocol to focus fetching only the
advertised set of Oids.
N.B.: because the refs aren't communicated, the verification happens
when fetching since the data needs to be fetched before
verifying. This is a trade-off with minimising the message payload for
verifying earlier.
Signed-off-by: Fintan Halpenny <fintan.halpenny@gmail.com>
X-Clacks-Overhead: GNU Terry Pratchett
When a fetch is user-requested, a timeout can be supplied that is passed
down to the worker.
When a fetch is service-requested, a default timeout is used.
Lorenz Leutgeb
Fintan Halpenny
cloudhead
Alexis Sellier