Module network_service

Background network service.

The NetworkService manages background tasks dedicated to connecting to other nodes. Importantly, its design is oriented towards the particular use case of the light client.

The NetworkService spawns one background task (using PlatformRef::spawn_task) for each active connection.

The objective of the NetworkService in general is to try stay connected as much as possible to the nodes of the peer-to-peer network of the chain, and maintain open substreams with them in order to send out requests (e.g. block requests) and notifications (e.g. block announces).

Connectivity to the network is performed in the background as an implementation detail of the service. The public API only allows emitting requests and notifications towards the already-connected nodes.

After a NetworkService is created, one can add chains using NetworkService::add_chain. If all references to a NetworkServiceChain are destroyed, the chain is automatically purged.

An important part of the API is the list of channel receivers of Event returned by NetworkServiceChain::subscribe. These channels inform the foreground about updates to the network connectivity.

Structs

CallProofRequestConfig

Description of a call proof request that can be sent to a peer.

ChainId

Identifier of a chain added through ChainNetwork::add_chain.

Config

Configuration for a NetworkService.

ConfigChain

See NetworkService::add_chain.

EncodedMerkleProof

Undecoded but valid Merkle proof.

NetworkService

NetworkServiceChain

PeerId

Identifier of a node of the network.

Enums

BanSeverity

Severity of a ban. See NetworkServiceChain::ban_and_disconnect.

BlocksRequestError

Error returned by NetworkServiceChain::blocks_request.

CallProofRequestError

Error returned by NetworkServiceChain::call_proof_request.

Event

Event that can happen on the network service.

QueueNotificationError

Error potentially returned when queueing a notification.

Role

Role a node reports playing on the network.

StorageProofRequestError

Error returned by NetworkServiceChain::storage_proof_request.

WarpSyncRequestError

Error returned by NetworkServiceChain::grandpa_warp_sync_request.