Crate libp2p::swarm

High-level network manager.

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 ConnectionHandler 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

• behaviour
• dial_opts
• dummy
• handler
  Once a connection to a remote peer is established, a ConnectionHandler negotiates and handles one or more specific protocols on the connection.
• keep_alive

Structs

• AddressChange
  FromSwarm variant that informs the behaviour that the ConnectedPoint of an existing connection has changed.
• AddressRecord
  An record in a prioritised list of addresses.
• ConnectionClosed
  FromSwarm variant that informs the behaviour about a closed connection to a peer.
• ConnectionCounters
  Network connection information.
• ConnectionDenied
  A connection was denied.
• ConnectionHandlerSelect
  Implementation of ConnectionHandler that combines two protocols into one.
• ConnectionId
  Connection identifier.
• ConnectionLimitDeprecated
  Information about a connection limit.
• ConnectionLimitsDeprecated
  The configurable connection limits.
• DialFailure
  FromSwarm variant that informs the behaviour that the dial to a known or unknown node failed.
• ExpiredExternalAddr
  FromSwarm variant that informs the behaviour that an external address was removed.
• ExpiredListenAddr
  FromSwarm variant that informs the behaviour that a multiaddr we were listening on has expired, which means that we are no longer listening on it.
• ExternalAddresses
  Utility struct for tracking the external addresses of a Swarm.
• IntoConnectionHandlerSelect
  Implementation of IntoConnectionHandler that combines two protocols into one.
• ListenAddresses
  Utility struct for tracking the addresses a Swarm is listening on.
• ListenFailure
  FromSwarm variant that informs the behaviour that an error happened on an incoming connection during its initial handshake.
• ListenerClosed
  FromSwarm variant that informs the behaviour that a listener closed.
• ListenerError
  FromSwarm variant that informs the behaviour that a listener experienced an error.
• NetworkInfo
  Information about the connections obtained by Swarm::network_info().
• NewExternalAddr
  FromSwarm variant that informs the behaviour that we have discovered a new external address for us.
• NewListenAddr
  FromSwarm variant that informs the behaviour that we have started listening on a new multiaddr.
• OneShotHandler
  A ConnectionHandler that opens a new substream for each request.
• OneShotHandlerConfig
  Configuration parameters for the OneShotHandler
• SubstreamProtocol
  Configuration of inbound or outbound substream protocol(s) for a ConnectionHandler.
• Swarm
  Contains the state of the network, plus the way it should behave.
• SwarmBuilder
  A SwarmBuilder provides an API for configuring and constructing a Swarm.
• SwarmPollParameters
  Parameters passed to poll(), that the NetworkBehaviour has access to.

Enums

• AddAddressResult
  The result of adding an address to an ordered list of addresses with associated scores.
• AddressScore
  The “score” of an address w.r.t. an ordered collection of addresses.
• CloseConnection
  The options which connections to close.
• ConnectionError
  Errors that can occur in the context of an established Connection.
• ConnectionHandlerEvent
  Event produced by a handler.
• ConnectionHandlerUpgrErr
  Error that can happen on an outbound substream opening attempt.
• DialError
  Possible errors when trying to establish or upgrade an outbound connection.
• FromSwarm
  Enumeration with the list of the possible events to pass to on_swarm_event.
• KeepAlive
  How long the connection should be kept alive.
• ListenError
  Possible errors when upgrading an inbound connection.
• NotifyHandler
  The options w.r.t. which connection handler to notify of an event.
• SwarmEvent
  Event generated by the Swarm.
• ToSwarm
  A command issued from a NetworkBehaviour for the Swarm.

Traits

• ConnectionHandler
  A handler for a set of protocols used on a connection with a remote.
• Executor
  Implemented on objects that can run a Future in the background.
• IntoConnectionHandlerDeprecated
  Prototype for a ConnectionHandler.
• NetworkBehaviour
  A NetworkBehaviour defines the behaviour of the local node on the network.
• PollParameters
  Parameters passed to poll(), that the NetworkBehaviour has access to.

Type Definitions

• NegotiatedSubstream
  Substream for which a protocol has been chosen.
• NetworkBehaviourActionDeprecated
• THandler
  ConnectionHandler of the NetworkBehaviour for all the protocols the NetworkBehaviour supports.
• THandlerErr
  Custom error that can be produced by the ConnectionHandler of the NetworkBehaviour.
• THandlerInEvent
  Custom event that can be received by the ConnectionHandler of the NetworkBehaviour.
• THandlerOutEvent
  Custom event that can be produced by the ConnectionHandler of the NetworkBehaviour.

Derive Macros

• NetworkBehaviour
  Generates a delegating NetworkBehaviour implementation for the struct this is used for. See the trait documentation for better description.