Module libp2p::swarm

High level manager of the network.

A Swarm contains the state of the network as a whole. The entire behaviour of a libp2p network can be controlled through the Swarm. The Swarm struct contains all active and pending connections to remotes and manages the state of all the substreams that have been opened, and all the upgrades that were built upon these substreams.

Initializing a Swarm

Creating a Swarm requires three things:

1. A network identity of the local node in form of a PeerId.
2. An implementation of the Transport trait. This is the type that will be used in order to reach nodes on the network based on their address. See the transport module for more information.
3. An implementation of the NetworkBehaviour trait. This is a state machine that defines how the swarm should behave once it is connected to a node.

Network Behaviour

The NetworkBehaviour trait is implemented on types that indicate to the swarm how it should behave. This includes which protocols are supported and which nodes to try to connect to. It is the NetworkBehaviour that controls what happens on the network. Multiple types that implement NetworkBehaviour can be composed into a single behaviour.

Protocols Handler

The ProtocolsHandler trait defines how each active connection to a remote should behave: how to handle incoming substreams, which protocols are supported, when to open a new outbound substream, etc.

Modules

protocols_handler	Once a connection to a remote peer is established, a ProtocolsHandler negotiates and handles one or more specific protocols on the connection.
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Structs

DummyBehaviour	Dummy implementation of NetworkBehaviour that doesn’t do anything.
ExpandedSwarm	Contains the state of the network, plus the way it should behave.
IntoProtocolsHandlerSelect	Implementation of IntoProtocolsHandler that combines two protocols into one.
OneShotHandler	A ProtocolsHandler that opens a new substream for each request.
OneShotHandlerConfig	Configuration parameters for the OneShotHandler
ProtocolsHandlerSelect	Implementation of ProtocolsHandler that combines two protocols into one.
SubstreamProtocol	Configuration of inbound or outbound substream protocol(s) for a ProtocolsHandler.
SwarmBuilder	A SwarmBuilder provides an API for configuring and constructing a Swarm, including the underlying Network.
SwarmPollParameters	Parameters passed to poll(), that the NetworkBehaviour has access to.

Enums

DialError	The possible failures of ExpandedSwarm::dial.
DialPeerCondition	The available conditions under which a new dialing attempt to a peer is initiated when requested by NetworkBehaviourAction::DialPeer.
KeepAlive	How long the connection should be kept alive.
NetworkBehaviourAction	An action that a NetworkBehaviour can trigger in the Swarm in whose context it is executing.
NotifyHandler	The options w.r.t. which connection handlers to notify of an event.
ProtocolsHandlerEvent	Event produced by a handler.
ProtocolsHandlerUpgrErr	Error that can happen on an outbound substream opening attempt.
SwarmEvent	Event generated by the Swarm.

Traits

IntoProtocolsHandler	Prototype for a ProtocolsHandler.
NetworkBehaviour	A behaviour for the network. Allows customizing the swarm.
NetworkBehaviourEventProcess	When deriving NetworkBehaviour this trait must by default be implemented for all the possible event types generated by the inner behaviours.
PollParameters	Parameters passed to poll(), that the NetworkBehaviour has access to.
ProtocolsHandler	A handler for a set of protocols used on a connection with a remote.

Type Definitions

NegotiatedSubstream	Substream for which a protocol has been chosen.
Swarm	Contains the state of the network, plus the way it should behave.