* More control & insight for k-buckets.
1) More control: It is now possible to disable automatic
insertions of peers into the routing table via a new
`KademliaBucketInserts` configuration option. The
default is `OnConnected`, but it can be set to `Manual`,
in which case `add_address` must be called explicitly.
In order to communicate all situations in which a user
of `Kademlia` may want to manually update the routing
table, two new events are introduced:
* `KademliaEvent::RoutablePeer`: When a connection to
a peer with a known listen address is established
which may be added to the routing table. This is
also emitted when automatic inserts are allowed but
the corresponding k-bucket is full.
* `KademliaEvent::PendingRoutablePeer`: When a connection
to a peer with a known listen address is established
which is pending insertion into the routing table
(but may not make it). This is only emitted when
`OnConnected` (i.e. automatic inserts) are used.
These complement the existing `UnroutablePeer` and
`RoutingUpdated` events. It is now also possible to
explicitly remove peers and addresses from the
routing table.
2) More insight: `Kademlia::kbuckets` now gives an
iterator over `KBucketRef`s and `Kademlia::bucket`
a particular `KBucketRef`. A `KBucketRef` in turn
allows iteration over its entries. In this way,
the full contents of the routing table can be
inspected, e.g. in order to decide which peer(s)
to remove.
* Update protocols/kad/src/behaviour.rs
* Update protocols/kad/src/behaviour.rs
Co-authored-by: Max Inden <mail@max-inden.de>
* Update CHANGELOG.
Co-authored-by: Max Inden <mail@max-inden.de>
- Update `libp2p-kad` CHANGELOG and increment version to 0.20.1.
- Update `libp2p` version to 0.20.1.
- Fix some linter warning in `libp2p-gossipsub` and increment
version to 0.19.3 and update CHANGELOG.
The extension paper S-Kademlia includes a proposal for lookups over
disjoint paths. Within vanilla Kademlia, queries keep track of the
closest nodes in a single bucket. Any adversary along the path can thus
influence all future paths, in case they can come up with the
next-closest (not overall closest) hops. S-Kademlia tries to solve the
attack above by querying over disjoint paths using multiple buckets.
To adjust the libp2p Kademlia implementation accordingly this change-set
introduces an additional peers iterator: `ClosestDisjointPeersIter`.
This new iterator wraps around a set of `ClosestPeersIter`
`ClosestDisjointPeersIter` enforces that each of the `ClosestPeersIter`
explore disjoint paths by having each peer instantly return that was
queried by a different iterator before.
* [libp2p-kad] Provide more insight and control into Kademlia queries.
More insight: The API allows iterating over the active queries and
inspecting their state and execution statistics.
More control: The API allows aborting queries prematurely
at any time.
To that end, API operations that initiate new queries return the query ID
and multi-phase queries such as `put_record` retain the query ID across all
phases, each phase being executed by a new (internal) query.
* Cleanup
* Cleanup
* Update examples and re-exports.
* Incorporate review feedback.
* Update CHANGELOG
* Update CHANGELOG
Co-authored-by: Max Inden <mail@max-inden.de>
`FixedPeersIter` requires the initial set of peers to be passed as
`PeerId`s and not as `Key<PeerId>`s. This commit removes the unnecessary
conversion.
Instead of creating unconstrained random number generators in quickcheck
tests to generate test data, have quickcheck provide a `Seed` to seed
those random number generators and thus make the test execution
deterministic / reproducible.
Make sure to decrease `num_waiting` when being notified of a peer
failure to allow an additional peer to be queried.
Given that `FixedPeersIter` is initialized with `replication_factor` by
`QueryPool` this bug will not surface today.
* protocols/kad/query/peers/closest: Consider K_VALUE nodes at init
By considering `K_VALUE` at `ClosestPeersIter` initialization, the initial peer
set length is independent of `num_results` and thus of the `replication_factor`.
* protocols/kad/src/behaviour/test: Enable building single nodes
Introduces the `build_node` function to build a single not connected
node. Along the way replace the notion of a `port_base` with returning
the actual `Multiaddr` of the node.
* protocols/kad/behaviour/test: Fix bootstrap test initialization
When looking for the closest node to a key, Kademlia considers
ALPHA_VALUE nodes to query at initialization. If `num_groups` is larger
than ALPHA_VALUE the remaining locally known nodes will not be
considered. Given that no other node is aware of them other than node 1,
they would be lost entirely. To prevent the above restrict `num_groups`
to be equal or smaller than ALPHA_VALUE.
* protocols/kad/behaviour/test: Fix put_record and get_provider
In the past, when trying to find the closest nodes to a key, Kademlia
would consider `num_result` amount of nodes to query out of all the
nodes it is aware of.
Both the `put_record` and the `get_provider` tests initialized their
swarms in the same way. The tests took the replication factor to use as
an input. The number of results to get was equal to the replication
factor. The amount of swarms to start was twice the replication factor.
Nodes would be grouped in two groups a replication factor nodes. The
first node would be aware of all of the nodes in the first group. The
last node of the first group would be aware of all the nodes in the
second group.
By coincidence (I assume) these numbers played together very well. At
initialization the first node would consider `num_results` amount of
peers (see first paragraph). It would then contact each of them. As the
first node is aware of the last node of the first group which in turn is
aware of all nodes in the second group, the first node would eventually
discover all nodes.
Recently the amount of nodes Kademlia considers at initialization when
looking for the nodes closest to a key was changed to only consider
ALPHA nodes.
With this in mind playing through the test setup above again would
result in (1) `replication_factor - ALPHA` nodes being entirely lost as
the first node would never consider them and (2) the first node probably
never contacting the last node out of the first group and thus not
discovering any nodes of the second group.
To keep the multi hop discovery in place while not basing ones test
setup on the lucky assumption of Kademlia considering replication factor
amount of nodes at initialization, this patch alters the two tests:
Build a fully connected set of nodes and one addition node (the first
node). Connect the first node to a single node of the fully connected
set (simulating a boot node). Continue as done previously.
Co-authored-by: Roman Borschel <romanb@users.noreply.github.com>
When not making progress for `parallelism` time a `ClosestPeersIter`
becomes `State::Stalled`. When stalled an iterator is allowed to make
more parallel requests up to `num_results`. If `num_results` is smaller
than `parallelism` make sure to still allow up to `parallelism` requests
in-flight.
Co-Authored-By: Roman Borschel <romanb@users.noreply.github.com>
A node receiving a `GetRecord` request first checks whether it has the
given record. If it does have the record it does not return closer
nodes.
A node that knows the record for the given key is likely within a
neighborhood of nodes that know the record as well. In addition the node
likely knows its neighboorhood well.
When querying for a key with a quorum of 1 the above behavior of only
returning the record but not any close peers is fine. Once one queries
with a higher quorum having a node respond with the record as well as
close nodes is likely going to speed up the query, given that the
returned peers probably know the record as well.
