Module channelmanager

The top-level channel management and payment tracking stuff lives here.

The ChannelManager is the main chunk of logic implementing the lightning protocol and is responsible for tracking which channels are open, HTLCs are in flight and reestablishing those upon reconnect to the relevant peer(s).

It does not manage routing logic (see Router for that) nor does it manage constructing on-chain transactions (it only monitors the chain to watch for any force-closes that might imply it needs to fail HTLCs/payments/channels it manages).

Structs

ChainParameters

Chain-related parameters used to construct a new ChannelManager.

ChannelCounterparty

Channel parameters which apply to our counterparty. These are split out from ChannelDetails to better separate parameters.

ChannelDetails

Details of a channel, as returned by ChannelManager::list_channels and ChannelManager::list_usable_channels

ChannelManager

Manager which keeps track of a number of channels and sends messages to the appropriate channel, also tracking HTLC preimages and forwarding onion packets appropriately.

ChannelManagerReadArgs

Arguments for the creation of a ChannelManager that are not deserialized.

CounterpartyForwardingInfo

Information needed for constructing an invoice route hint for this channel.

InterceptId

An identifier used to uniquely identify an intercepted HTLC to LDK.

PaymentId

A user-provided identifier in ChannelManager::send_payment used to uniquely identify a payment and ensure idempotency in LDK.

PhantomRouteHints

Route hints used in constructing invoices for [phantom node payents].

RecipientOnionFields

Information which is provided, encrypted, to the payment recipient when sending HTLCs.

Enums

ChannelShutdownState

Further information on the details of the channel shutdown. Upon channels being forced closed (i.e. commitment transaction confirmation detected by ChainMonitor), ChannelShutdownState will be set to ShutdownComplete or the channel will be removed shortly. Also note, that in normal operation, peers could disconnect at any of these states and require peer re-connection before making progress onto other states

FailureCode

This enum is used to specify which error data to send to peers when failing back an HTLC using ChannelManager::fail_htlc_backwards_with_reason.

PaymentSendFailure

If a payment fails to send with ChannelManager::send_payment_with_route, it can be in one of several states. This enum is returned as the Err() type describing which state the payment is in, see the description of individual enum states for more.

ProbeSendFailure

Indicates that we failed to send a payment probe. Further errors may be surfaced later via Event::ProbeFailed.

RecentPaymentDetails

Used by ChannelManager::list_recent_payments to express the status of recent payments. These include payments that have yet to find a successful path, or have unresolved HTLCs.

Retry

Strategies available to retry payment path failures.

RetryableSendFailure

Indicates an immediate error on ChannelManager::send_payment. Further errors may be surfaced later via Event::PaymentPathFailed and Event::PaymentFailed.

Constants

BREAKDOWN_TIMEOUT

The amount of time in blocks we require our counterparty wait to claim their money (ie time between when we, or our watchtower, must check for them having broadcast a theft transaction).

MIN_CLTV_EXPIRY_DELTA

The minimum number of blocks between an inbound HTLC’s CLTV and the corresponding outbound HTLC’s CLTV. The current default represents roughly seven hours of blocks at six blocks/hour.

MIN_FINAL_CLTV_EXPIRY_DELTA

Minimum CLTV difference between the current block height and received inbound payments. Invoices generated for payment to us must set their min_final_cltv_expiry_delta field to at least this value.

Traits

AChannelManager

A trivial trait which describes any ChannelManager.

Functions

provided_init_features

Fetches the set of InitFeatures flags that are provided by or required by ChannelManager.

Type Aliases

SimpleArcChannelManager

SimpleArcChannelManager is useful when you need a ChannelManager with a static lifetime, e.g. when you’re using lightning-net-tokio (since tokio::spawn requires parameters with static lifetimes). Other times you can afford a reference, which is more efficient, in which case SimpleRefChannelManager is the more appropriate type. Defining these type aliases prevents issues such as overly long function definitions. Note that the ChannelManager can take any type that implements NodeSigner, EntropySource, and SignerProvider for its keys manager, or, respectively, Router for its router, but this type alias chooses the concrete types of KeysManager and DefaultRouter.

SimpleRefChannelManager

SimpleRefChannelManager is a type alias for a ChannelManager reference, and is the reference counterpart to the SimpleArcChannelManager type alias. Use this type by default when you don’t need a ChannelManager with a static lifetime. You’ll need a static lifetime in cases such as usage of lightning-net-tokio (since tokio::spawn requires parameters with static lifetimes). But if this is not necessary, using a reference is more efficient. Defining these type aliases issues such as overly long function definitions. Note that the ChannelManager can take any type that implements NodeSigner, EntropySource, and SignerProvider for its keys manager, or, respectively, Router for its router, but this type alias chooses the concrete types of KeysManager and DefaultRouter.