* Fix self-dialing in Kademlia.
Addresses https://github.com/libp2p/rust-libp2p/issues/341 which is the cause
for one of the observations made in https://github.com/libp2p/rust-libp2p/issues/1053.
However, the latter is not assumed to be fully addressed by these changes and
needs further investigation.
Currently, whenever a search for a key yields a response containing the initiating
peer as one of the closest peers known to the remote, the local node
would attempt to dial itself. That attempt is ignored by the Swarm, but
the Kademlia behaviour now believes it still has a query ongoing which is
always doomed to time out. That timeout delays successful completion of the query.
Hence, any query where a remote responds with the ID of the local node takes at
least as long as the `rpc_timeout` to complete, which possibly affects almost
all queries in smaller clusters where every node knows about every other.
This problem is fixed here by ensuring that Kademlia never tries to dial the local node.
Furthermore, `Discovered` events are no longer emitted for the local node
and it is not inserted into the `untrusted_addresses` from discovery, as described
in #341.
This commit also includes a change to the condition for freezing / terminating
a Kademlia query upon receiving a response. Specifically, the condition is
tightened such that it only applies if in addition to `parallelism`
consecutive responses that failed to yield a peer closer to the target, the
last response must also either not have reported any new peer or the
number of collected peers has already reached the number of desired results.
In effect, a Kademlia query now tries harder to actually return `k`
closest peers.
Tests have been refactored and expanded.
* Add another comment.
* libp2p-ping improvements.
* re #950: Removes use of the `OneShotHandler`, but still sending each
ping over a new substream, as seems to be intentional since #828.
* re #842: Adds an integration test that exercises the ping behaviour through
a Swarm, requiring the RTT to be below a threshold. This requires disabling
Nagle's algorithm as it can interact badly with delayed ACKs (and has been
observed to do so in the context of the new ping example and integration test).
* re #864: Control of the inbound and outbound (sub)stream protocol upgrade
timeouts has been moved from the `NodeHandlerWrapperBuilder` to the
`ProtocolsHandler`. That may also alleviate the need for a custom timeout
on an `OutboundSubstreamRequest` as a `ProtocolsHandler` is now free to
adjust these timeouts over time.
Other changes:
* A new ping example.
* Documentation improvements.
* More documentation improvements.
* Add PingPolicy and ensure no event is dropped.
* Remove inbound_timeout/outbound_timeout.
As per review comment, the inbound timeout is now configured
as part of the `listen_protocol` and the outbound timeout as
part of the `OutboundSubstreamRequest`.
* Simplify and generalise.
Generalise `ListenProtocol` to `SubstreamProtocol`, reusing it in
the context of `ProtocolsHandlerEvent::OutboundSubstreamRequest`.
* Doc comments for SubstreamProtocol.
* Adapt to changes in master.
* Relax upper bound for ping integration test rtt.
For "slow" CI build machines?
Update the protocols and transport subdirectories to the 2018 edition.
NB: The websocket transport cannot be moved to 2018 edition due to
websocket-rs's use of the keyword async as the name of a module.
* Rework Kademlia for the new design
* Minor work on protocol.rs
* More work
* Remove QueryTarget::FindValue
* Finish work on query
* Query timeout test
* Work on topology
* More work
* Update protocols/kad/src/topology.rs
Co-Authored-By: tomaka <pierre.krieger1708@gmail.com>
* Fix trailing whitespaces
* Use if let
