Crate cumulus_pallet_xcmp_queue

A pallet which uses the XCMP transport layer to handle both incoming and outgoing XCM message sending and dispatch, queuing, signalling and backpressure. To do so, it implements:

• XcmpMessageHandler
• XcmpMessageSource

Also provides an implementation of SendXcm which can be placed in a router tuple for relaying XCM over XCMP if the destination is Parent/Parachain. It requires an implementation of XcmExecutor for dispatching incoming XCM messages.

To prevent out of memory errors on the OutboundXcmpMessages queue, an exponential fee factor (DeliveryFeeFactor) is set, much like the one used in DMP. The fee factor increases whenever the total size of messages in a particular channel passes a threshold. This threshold is defined as a percentage of the maximum total size the channel can have. More concretely, the threshold is max_total_size / THRESHOLD_FACTOR, where:

• max_total_size is the maximum size, in bytes, of the channel, not number of messages. It is defined in the channel configuration.
• THRESHOLD_FACTOR just declares which percentage of the max size is the actual threshold. If it’s 2, then the threshold is half of the max size, if it’s 4, it’s a quarter, and so on.

Re-exports

pub use weights::WeightInfo;

pub use weights_ext::WeightInfoExt;

pub use pallet::*;

Modules

bridging

delivery_fee_constants

Constants related to delivery fee calculation

migration

A module that is responsible for migration of storage.

pallet

The pallet module in each FRAME pallet hosts the most important items needed to construct this pallet.

weights

Autogenerated weights for cumulus_pallet_xcmp_queue

weights_ext

Weight-related utilities.

Structs

OutboundChannelDetails

Struct containing detailed information about the outbound channel.

QueueConfigData

Enums

ChannelSignal

OutboundState

Constants

MAX_SIGNALS_PER_PAGE

The maximum number of signals that we can have in an XCMP page.

XCM_BATCH_SIZE

The size of an XCM messages batch.

Type Aliases

MaxXcmpMessageLenOf

The max length of an XCMP message.

OverweightIndex

Index used to identify overweight XCMs.