From 9b60d7cf1d87094814893903ef187c3769542d66 Mon Sep 17 00:00:00 2001 From: Jeffrey Czyz Date: Fri, 3 Nov 2023 14:44:45 -0500 Subject: [PATCH 1/9] Break ChannelManager docs into sections ChannelManager docs aren't very approachable as they consist of a large wall of texts without much direction. As a first step of improvement, add sections to help delineate the existing text and make it easier to scan. --- lightning/src/ln/channelmanager.rs | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/lightning/src/ln/channelmanager.rs b/lightning/src/ln/channelmanager.rs index bddcd4c9b81..13210c3772b 100644 --- a/lightning/src/ln/channelmanager.rs +++ b/lightning/src/ln/channelmanager.rs @@ -1115,6 +1115,8 @@ where /// Implements [`ChannelMessageHandler`], handling the multi-channel parts and passing things through /// to individual Channels. /// +/// # Persistence +/// /// Implements [`Writeable`] to write out all channel state to disk. Implies [`peer_disconnected`] for /// all peers during write/read (though does not modify this instance, only the instance being /// serialized). This will result in any channels which have not yet exchanged [`funding_created`] (i.e., @@ -1134,12 +1136,16 @@ where /// tells you the last block hash which was connected. You should get the best block tip before using the manager. /// See [`chain::Listen`] and [`chain::Confirm`] for more details. /// +/// # `ChannelUpdate` Messages +/// /// Note that `ChannelManager` is responsible for tracking liveness of its channels and generating /// [`ChannelUpdate`] messages informing peers that the channel is temporarily disabled. To avoid /// spam due to quick disconnection/reconnection, updates are not sent until the channel has been /// offline for a full minute. In order to track this, you must call /// [`timer_tick_occurred`] roughly once per minute, though it doesn't have to be perfect. /// +/// # DoS Mitigation +/// /// To avoid trivial DoS issues, `ChannelManager` limits the number of inbound connections and /// inbound channels without confirmed funding transactions. This may result in nodes which we do /// not have a channel with being unable to connect to us or open new channels with us if we have @@ -1149,6 +1155,8 @@ where /// exempted from the count of unfunded channels. Similarly, outbound channels and connections are /// never limited. Please ensure you limit the count of such channels yourself. /// +/// # Type Aliases +/// /// Rather than using a plain `ChannelManager`, it is preferable to use either a [`SimpleArcChannelManager`] /// a [`SimpleRefChannelManager`], for conciseness. See their documentation for more details, but /// essentially you should default to using a [`SimpleRefChannelManager`], and use a From f998e718435e3601007e566dc8ada61417353719 Mon Sep 17 00:00:00 2001 From: Jeffrey Czyz Date: Fri, 3 Nov 2023 16:23:18 -0500 Subject: [PATCH 2/9] Re-write ChannelManager summary documentation --- lightning/src/ln/channelmanager.rs | 31 ++++++++++++++++++++++++++---- 1 file changed, 27 insertions(+), 4 deletions(-) diff --git a/lightning/src/ln/channelmanager.rs b/lightning/src/ln/channelmanager.rs index 13210c3772b..b09310e8dc5 100644 --- a/lightning/src/ln/channelmanager.rs +++ b/lightning/src/ln/channelmanager.rs @@ -1109,11 +1109,31 @@ where fn get_cm(&self) -> &ChannelManager { self } } -/// 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. +/// A lightning node's channel state machine and payment management logic, which facilitates +/// sending, forwarding, and receiving payments through lightning channels. /// -/// Implements [`ChannelMessageHandler`], handling the multi-channel parts and passing things through -/// to individual Channels. +/// [`ChannelManager`] is parameterized by a number of components to achieve this. +/// - [`chain::Watch`] (typically [`ChainMonitor`]) for on-chain monitoring and enforcement of each +/// channel +/// - [`BroadcasterInterface`] for broadcasting transactions related to opening, funding, and +/// closing channels +/// - [`EntropySource`] for providing random data needed for cryptographic operations +/// - [`NodeSigner`] for cryptographic operations scoped to the node +/// - [`SignerProvider`] for providing signers whose operations are scoped to individual channels +/// - [`FeeEstimator`] to determine transaction fee rates needed to have a transaction mined in a +/// timely manner +/// - [`Router`] for finding payment paths when initiating and retrying payments +/// - [`Logger`] for logging operational information of varying degrees +/// +/// Additionally, it implements the following traits: +/// - [`ChannelMessageHandler`] to handle off-chain channel activity from peers +/// - [`MessageSendEventsProvider`] to similarly send such messages to peers +/// - [`OffersMessageHandler`] for BOLT 12 message handling and sending +/// - [`EventsProvider`] to generate user-actionable [`Event`]s +/// - [`chain::Listen`] and [`chain::Confirm`] for notification of on-chain activity +/// +/// Thus, [`ChannelManager`] is typically used to parameterize a [`MessageHandler`] and an +/// [`OnionMessenger`]. The latter is required to support BOLT 12 functionality. /// /// # Persistence /// @@ -1163,6 +1183,9 @@ where /// [`SimpleArcChannelManager`] when you require a `ChannelManager` with a static lifetime, such as when /// you're using lightning-net-tokio. /// +/// [`ChainMonitor`]: crate::chain::chainmonitor::ChainMonitor +/// [`MessageHandler`]: crate::ln::peer_handler::MessageHandler +/// [`OnionMessenger`]: crate::onion_message::messenger::OnionMessenger /// [`peer_disconnected`]: msgs::ChannelMessageHandler::peer_disconnected /// [`funding_created`]: msgs::FundingCreated /// [`funding_transaction_generated`]: Self::funding_transaction_generated From 19e50ebb7cc041341276d88ba74f5e268e263254 Mon Sep 17 00:00:00 2001 From: Jeffrey Czyz Date: Fri, 3 Nov 2023 17:02:15 -0500 Subject: [PATCH 3/9] Contrast ChannelManager and ChannelMonitor in docs --- lightning/src/ln/channelmanager.rs | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/lightning/src/ln/channelmanager.rs b/lightning/src/ln/channelmanager.rs index b09310e8dc5..3674a17093a 100644 --- a/lightning/src/ln/channelmanager.rs +++ b/lightning/src/ln/channelmanager.rs @@ -1135,6 +1135,22 @@ where /// Thus, [`ChannelManager`] is typically used to parameterize a [`MessageHandler`] and an /// [`OnionMessenger`]. The latter is required to support BOLT 12 functionality. /// +/// # `ChannelManager` vs `ChannelMonitor` +/// +/// It's important to distinguish between the *off-chain* management and *on-chain* enforcement of +/// lightning channels. [`ChannelManager`] exchanges messages with peers to manage the off-chain +/// state of each channel. During this process, it generates a [`ChannelMonitor`] for each channel +/// and a [`ChannelMonitorUpdate`] for each relevant change, notifying its parameterized +/// [`chain::Watch`] of them. +/// +/// An implementation of [`chain::Watch`], such as [`ChainMonitor`], is responsible for aggregating +/// these [`ChannelMonitor`]s and applying any [`ChannelMonitorUpdate`]s to them. It then monitors +/// for any pertinent on-chain activity, enforcing claims as needed. +/// +/// This division of off-chain management and on-chain enforcement allows for interesting node +/// setups. For instance, on-chain enforcement could be moved to a separate host or have added +/// redundancy, possibly as a watchtower. See [`chain::Watch`] for the relevant interface. +/// /// # Persistence /// /// Implements [`Writeable`] to write out all channel state to disk. Implies [`peer_disconnected`] for From c39c398f0618835201fb741b1976952c3f9180fa Mon Sep 17 00:00:00 2001 From: Jeffrey Czyz Date: Fri, 17 Nov 2023 17:58:56 -0600 Subject: [PATCH 4/9] ChannelManager initialization docs with example --- lightning/src/ln/channelmanager.rs | 71 ++++++++++++++++++++++++++++++ lightning/src/sign/mod.rs | 13 ++++++ 2 files changed, 84 insertions(+) diff --git a/lightning/src/ln/channelmanager.rs b/lightning/src/ln/channelmanager.rs index 3674a17093a..35ae80e01bb 100644 --- a/lightning/src/ln/channelmanager.rs +++ b/lightning/src/ln/channelmanager.rs @@ -1151,6 +1151,77 @@ where /// setups. For instance, on-chain enforcement could be moved to a separate host or have added /// redundancy, possibly as a watchtower. See [`chain::Watch`] for the relevant interface. /// +/// # Initialization +/// +/// Use [`ChannelManager::new`] with the most recent [`BlockHash`] when creating a fresh instance. +/// Otherwise, if restarting, construct [`ChannelManagerReadArgs`] with the necessary parameters and +/// references to any deserialized [`ChannelMonitor`]s that were previously persisted. Use this to +/// deserialize the [`ChannelManager`] and feed it any new chain data since it was last online, as +/// detailed in the [`ChannelManagerReadArgs`] documentation. +/// +/// ``` +/// use bitcoin::BlockHash; +/// use bitcoin::network::constants::Network; +/// use lightning::chain::BestBlock; +/// # use lightning::chain::channelmonitor::ChannelMonitor; +/// use lightning::ln::channelmanager::{ChainParameters, ChannelManager, ChannelManagerReadArgs}; +/// # use lightning::routing::gossip::NetworkGraph; +/// use lightning::util::config::UserConfig; +/// use lightning::util::ser::ReadableArgs; +/// +/// # fn read_channel_monitors() -> Vec> { vec![] } +/// # fn example< +/// # 'a, +/// # L: lightning::util::logger::Logger, +/// # ES: lightning::sign::EntropySource, +/// # S: for <'b> lightning::routing::scoring::LockableScore<'b, ScoreLookUp = SL>, +/// # SL: lightning::routing::scoring::ScoreLookUp, +/// # SP: Sized, +/// # R: lightning::io::Read, +/// # >( +/// # fee_estimator: &dyn lightning::chain::chaininterface::FeeEstimator, +/// # chain_monitor: &dyn lightning::chain::Watch, +/// # tx_broadcaster: &dyn lightning::chain::chaininterface::BroadcasterInterface, +/// # router: &lightning::routing::router::DefaultRouter<&NetworkGraph<&'a L>, &'a L, &ES, &S, SP, SL>, +/// # logger: &L, +/// # entropy_source: &ES, +/// # node_signer: &dyn lightning::sign::NodeSigner, +/// # signer_provider: &lightning::sign::DynSignerProvider, +/// # best_block: lightning::chain::BestBlock, +/// # current_timestamp: u32, +/// # mut reader: R, +/// # ) -> Result<(), lightning::ln::msgs::DecodeError> { +/// // Fresh start with no channels +/// let params = ChainParameters { +/// network: Network::Bitcoin, +/// best_block, +/// }; +/// let default_config = UserConfig::default(); +/// let channel_manager = ChannelManager::new( +/// fee_estimator, chain_monitor, tx_broadcaster, router, logger, entropy_source, node_signer, +/// signer_provider, default_config, params, current_timestamp +/// ); +/// +/// // Restart from deserialized data +/// let mut channel_monitors = read_channel_monitors(); +/// let args = ChannelManagerReadArgs::new( +/// entropy_source, node_signer, signer_provider, fee_estimator, chain_monitor, tx_broadcaster, +/// router, logger, default_config, channel_monitors.iter_mut().collect() +/// ); +/// let (block_hash, channel_manager) = +/// <(BlockHash, ChannelManager<_, _, _, _, _, _, _, _>)>::read(&mut reader, args)?; +/// +/// // Update the ChannelManager and ChannelMonitors with the latest chain data +/// // ... +/// +/// // Move the monitors to the ChannelManager's chain::Watch parameter +/// for monitor in channel_monitors { +/// chain_monitor.watch_channel(monitor.get_funding_txo().0, monitor); +/// } +/// # Ok(()) +/// # } +/// ``` +/// /// # Persistence /// /// Implements [`Writeable`] to write out all channel state to disk. Implies [`peer_disconnected`] for diff --git a/lightning/src/sign/mod.rs b/lightning/src/sign/mod.rs index a7237493be7..17a907d19d6 100644 --- a/lightning/src/sign/mod.rs +++ b/lightning/src/sign/mod.rs @@ -736,6 +736,19 @@ pub trait NodeSigner { fn sign_gossip_message(&self, msg: UnsignedGossipMessage) -> Result; } +// Primarily needed in doctests because of https://github.com/rust-lang/rust/issues/67295 +/// A dynamic [`SignerProvider`] temporarily needed for doc tests. +#[cfg(taproot)] +#[doc(hidden)] +#[deprecated(note = "Remove once taproot cfg is removed")] +pub type DynSignerProvider = dyn SignerProvider; + +/// A dynamic [`SignerProvider`] temporarily needed for doc tests. +#[cfg(not(taproot))] +#[doc(hidden)] +#[deprecated(note = "Remove once taproot cfg is removed")] +pub type DynSignerProvider = dyn SignerProvider; + /// A trait that can return signer instances for individual channels. pub trait SignerProvider { /// A type which implements [`WriteableEcdsaChannelSigner`] which will be returned by [`Self::derive_channel_signer`]. From f3db18487613b24ee8bdde25a0b753aebcdd3be6 Mon Sep 17 00:00:00 2001 From: Jeffrey Czyz Date: Tue, 26 Dec 2023 22:06:56 -0500 Subject: [PATCH 5/9] Add an operations section to ChannelManager docs --- lightning/src/ln/channelmanager.rs | 37 +++++++++++++++++++++++++++++- 1 file changed, 36 insertions(+), 1 deletion(-) diff --git a/lightning/src/ln/channelmanager.rs b/lightning/src/ln/channelmanager.rs index 35ae80e01bb..aa3b2addc2a 100644 --- a/lightning/src/ln/channelmanager.rs +++ b/lightning/src/ln/channelmanager.rs @@ -1222,6 +1222,29 @@ where /// # } /// ``` /// +/// # Operation +/// +/// The following is required for [`ChannelManager`] to function properly: +/// - Handle messages from peers using its [`ChannelMessageHandler`] implementation (typically +/// called by [`PeerManager::read_event`] when processing network I/O) +/// - Send messages to peers obtained via its [`MessageSendEventsProvider`] implementation +/// (typically initiated when [`PeerManager::process_events`] is called) +/// - Feed on-chain activity using either its [`chain::Listen`] or [`chain::Confirm`] implementation +/// as documented by those traits +/// - Perform any periodic channel and payment checks by calling [`timer_tick_occurred`] roughly +/// every minute +/// - Persist to disk whenever [`get_and_clear_needs_persistence`] returns `true` using a +/// [`Persister`] such as a [`KVStore`] implementation +/// - Handle [`Event`]s obtained via its [`EventsProvider`] implementation +/// +/// The [`Future`] returned by [`get_event_or_persistence_needed_future`] is useful in determining +/// when the last two requirements need to be checked. +/// +/// The [`lightning-block-sync`] and [`lightning-transaction-sync`] crates provide utilities that +/// simplify feeding in on-chain activity using the [`chain::Listen`] and [`chain::Confirm`] traits, +/// respectively. The remaining requirements can be met using the [`lightning-background-processor`] +/// crate. For languages other than Rust, the availability of similar utilities may vary. +/// /// # Persistence /// /// Implements [`Writeable`] to write out all channel state to disk. Implies [`peer_disconnected`] for @@ -1273,13 +1296,22 @@ where /// [`ChainMonitor`]: crate::chain::chainmonitor::ChainMonitor /// [`MessageHandler`]: crate::ln::peer_handler::MessageHandler /// [`OnionMessenger`]: crate::onion_message::messenger::OnionMessenger +/// [`PeerManager::read_event`]: crate::ln::peer_handler::PeerManager::read_event +/// [`PeerManager::process_events`]: crate::ln::peer_handler::PeerManager::process_events +/// [`timer_tick_occurred`]: Self::timer_tick_occurred +/// [`get_and_clear_needs_persistence`]: Self::get_and_clear_needs_persistence +/// [`Persister`]: crate::util::persist::Persister +/// [`KVStore`]: crate::util::persist::KVStore +/// [`get_event_or_persistence_needed_future`]: Self::get_event_or_persistence_needed_future +/// [`lightning-block-sync`]: https://docs.rs/lightning_block_sync/latest/lightning_block_sync +/// [`lightning-transaction-sync`]: https://docs.rs/lightning_transaction_sync/latest/lightning_transaction_sync +/// [`lightning-background-processor`]: https://docs.rs/lightning_background_processor/lightning_background_processor /// [`peer_disconnected`]: msgs::ChannelMessageHandler::peer_disconnected /// [`funding_created`]: msgs::FundingCreated /// [`funding_transaction_generated`]: Self::funding_transaction_generated /// [`BlockHash`]: bitcoin::hash_types::BlockHash /// [`update_channel`]: chain::Watch::update_channel /// [`ChannelUpdate`]: msgs::ChannelUpdate -/// [`timer_tick_occurred`]: Self::timer_tick_occurred /// [`read`]: ReadableArgs::read // // Lock order: @@ -8879,6 +8911,9 @@ where } /// Returns true if this [`ChannelManager`] needs to be persisted. + /// + /// See [`Self::get_event_or_persistence_needed_future`] for retrieving a [`Future`] that + /// indicates this should be checked. pub fn get_and_clear_needs_persistence(&self) -> bool { self.needs_persist_flag.swap(false, Ordering::AcqRel) } From 11d07c6252d627ff0a8e9e53b61d38626ee28976 Mon Sep 17 00:00:00 2001 From: Jeffrey Czyz Date: Thu, 28 Dec 2023 17:00:16 -0600 Subject: [PATCH 6/9] Add a channels section to ChannelManager docs --- lightning/src/ln/channelmanager.rs | 168 +++++++++++++++++++++++++++++ 1 file changed, 168 insertions(+) diff --git a/lightning/src/ln/channelmanager.rs b/lightning/src/ln/channelmanager.rs index aa3b2addc2a..e35dcdf2a0d 100644 --- a/lightning/src/ln/channelmanager.rs +++ b/lightning/src/ln/channelmanager.rs @@ -1245,6 +1245,169 @@ where /// respectively. The remaining requirements can be met using the [`lightning-background-processor`] /// crate. For languages other than Rust, the availability of similar utilities may vary. /// +/// # Channels +/// +/// [`ChannelManager`]'s primary function involves managing a channel state. Without channels, +/// payments can't be sent. Use [`list_channels`] or [`list_usable_channels`] for a snapshot of the +/// currently open channels. +/// +/// ``` +/// # use lightning::ln::channelmanager::AChannelManager; +/// # +/// # fn example(channel_manager: T) { +/// # let channel_manager = channel_manager.get_cm(); +/// let channels = channel_manager.list_usable_channels(); +/// for details in channels { +/// println!("{:?}", details); +/// } +/// # } +/// ``` +/// +/// Each channel is identified using a [`ChannelId`], which will change throughout the channel's +/// life cycle. Additionally, channels are assigned a `user_channel_id`, which is given in +/// [`Event`]s associated with the channel and serves as a fixed identifier but is otherwise unused +/// by [`ChannelManager`]. +/// +/// ## Opening Channels +/// +/// To an open a channel with a peer, call [`create_channel`]. This will initiate the process of +/// opening an outbound channel, which requires self-funding when handling +/// [`Event::FundingGenerationReady`]. +/// +/// ``` +/// # use bitcoin::{ScriptBuf, Transaction}; +/// # use bitcoin::secp256k1::PublicKey; +/// # use lightning::ln::channelmanager::AChannelManager; +/// # use lightning::events::{Event, EventsProvider}; +/// # +/// # trait Wallet { +/// # fn create_funding_transaction( +/// # &self, _amount_sats: u64, _output_script: ScriptBuf +/// # ) -> Transaction; +/// # } +/// # +/// # fn example(channel_manager: T, wallet: W, peer_id: PublicKey) { +/// # let channel_manager = channel_manager.get_cm(); +/// let value_sats = 1_000_000; +/// let push_msats = 10_000_000; +/// match channel_manager.create_channel(peer_id, value_sats, push_msats, 42, None, None) { +/// Ok(channel_id) => println!("Opening channel {}", channel_id), +/// Err(e) => println!("Error opening channel: {:?}", e), +/// } +/// +/// // On the event processing thread once the peer has responded +/// channel_manager.process_pending_events(&|event| match event { +/// Event::FundingGenerationReady { +/// temporary_channel_id, counterparty_node_id, channel_value_satoshis, output_script, +/// user_channel_id, .. +/// } => { +/// assert_eq!(user_channel_id, 42); +/// let funding_transaction = wallet.create_funding_transaction( +/// channel_value_satoshis, output_script +/// ); +/// match channel_manager.funding_transaction_generated( +/// &temporary_channel_id, &counterparty_node_id, funding_transaction +/// ) { +/// Ok(()) => println!("Funding channel {}", temporary_channel_id), +/// Err(e) => println!("Error funding channel {}: {:?}", temporary_channel_id, e), +/// } +/// }, +/// Event::ChannelPending { channel_id, user_channel_id, former_temporary_channel_id, .. } => { +/// assert_eq!(user_channel_id, 42); +/// println!( +/// "Channel {} now {} pending (funding transaction has been broadcasted)", channel_id, +/// former_temporary_channel_id.unwrap() +/// ); +/// }, +/// Event::ChannelReady { channel_id, user_channel_id, .. } => { +/// assert_eq!(user_channel_id, 42); +/// println!("Channel {} ready", channel_id); +/// }, +/// // ... +/// # _ => {}, +/// }); +/// # } +/// ``` +/// +/// ## Accepting Channels +/// +/// Inbound channels are initiated by peers and are automatically accepted unless [`ChannelManager`] +/// has [`UserConfig::manually_accept_inbound_channels`] set. In that case, the channel may be +/// either accepted or rejected when handling [`Event::OpenChannelRequest`]. +/// +/// ``` +/// # use bitcoin::secp256k1::PublicKey; +/// # use lightning::ln::channelmanager::AChannelManager; +/// # use lightning::events::{Event, EventsProvider}; +/// # +/// # fn is_trusted(counterparty_node_id: PublicKey) -> bool { +/// # // ... +/// # unimplemented!() +/// # } +/// # +/// # fn example(channel_manager: T) { +/// # let channel_manager = channel_manager.get_cm(); +/// channel_manager.process_pending_events(&|event| match event { +/// Event::OpenChannelRequest { temporary_channel_id, counterparty_node_id, .. } => { +/// if !is_trusted(counterparty_node_id) { +/// match channel_manager.force_close_without_broadcasting_txn( +/// &temporary_channel_id, &counterparty_node_id +/// ) { +/// Ok(()) => println!("Rejecting channel {}", temporary_channel_id), +/// Err(e) => println!("Error rejecting channel {}: {:?}", temporary_channel_id, e), +/// } +/// return; +/// } +/// +/// let user_channel_id = 43; +/// match channel_manager.accept_inbound_channel( +/// &temporary_channel_id, &counterparty_node_id, user_channel_id +/// ) { +/// Ok(()) => println!("Accepting channel {}", temporary_channel_id), +/// Err(e) => println!("Error accepting channel {}: {:?}", temporary_channel_id, e), +/// } +/// }, +/// // ... +/// # _ => {}, +/// }); +/// # } +/// ``` +/// +/// ## Closing Channels +/// +/// There are two ways to close a channel: either cooperatively using [`close_channel`] or +/// unilaterally using [`force_close_broadcasting_latest_txn`]. The former is ideal as it makes for +/// lower fees and immediate access to funds. However, the latter may be necessary if the +/// counterparty isn't behaving properly or has gone offline. [`Event::ChannelClosed`] is generated +/// once the channel has been closed successfully. +/// +/// ``` +/// # use bitcoin::secp256k1::PublicKey; +/// # use lightning::ln::ChannelId; +/// # use lightning::ln::channelmanager::AChannelManager; +/// # use lightning::events::{Event, EventsProvider}; +/// # +/// # fn example( +/// # channel_manager: T, channel_id: ChannelId, counterparty_node_id: PublicKey +/// # ) { +/// # let channel_manager = channel_manager.get_cm(); +/// match channel_manager.close_channel(&channel_id, &counterparty_node_id) { +/// Ok(()) => println!("Closing channel {}", channel_id), +/// Err(e) => println!("Error closing channel {}: {:?}", channel_id, e), +/// } +/// +/// // On the event processing thread +/// channel_manager.process_pending_events(&|event| match event { +/// Event::ChannelClosed { channel_id, user_channel_id, .. } => { +/// assert_eq!(user_channel_id, 42); +/// println!("Channel {} closed", channel_id); +/// }, +/// // ... +/// # _ => {}, +/// }); +/// # } +/// ``` +/// /// # Persistence /// /// Implements [`Writeable`] to write out all channel state to disk. Implies [`peer_disconnected`] for @@ -1306,6 +1469,11 @@ where /// [`lightning-block-sync`]: https://docs.rs/lightning_block_sync/latest/lightning_block_sync /// [`lightning-transaction-sync`]: https://docs.rs/lightning_transaction_sync/latest/lightning_transaction_sync /// [`lightning-background-processor`]: https://docs.rs/lightning_background_processor/lightning_background_processor +/// [`list_channels`]: Self::list_channels +/// [`list_usable_channels`]: Self::list_usable_channels +/// [`create_channel`]: Self::create_channel +/// [`close_channel`]: Self::force_close_broadcasting_latest_txn +/// [`force_close_broadcasting_latest_txn`]: Self::force_close_broadcasting_latest_txn /// [`peer_disconnected`]: msgs::ChannelMessageHandler::peer_disconnected /// [`funding_created`]: msgs::FundingCreated /// [`funding_transaction_generated`]: Self::funding_transaction_generated From 7cf899bfc9223f3736f9635d294c0485ddf5219d Mon Sep 17 00:00:00 2001 From: Jeffrey Czyz Date: Tue, 26 Dec 2023 22:13:52 -0500 Subject: [PATCH 7/9] Add a payments section to ChannelManager docs --- lightning/src/ln/channelmanager.rs | 127 +++++++++++++++++++++++++++++ 1 file changed, 127 insertions(+) diff --git a/lightning/src/ln/channelmanager.rs b/lightning/src/ln/channelmanager.rs index e35dcdf2a0d..dc170b652b5 100644 --- a/lightning/src/ln/channelmanager.rs +++ b/lightning/src/ln/channelmanager.rs @@ -1408,6 +1408,124 @@ where /// # } /// ``` /// +/// # Payments +/// +/// [`ChannelManager`] is responsible for sending, forwarding, and receiving payments through its +/// channels. A payment is typically initiated from a [BOLT 11] invoice or a [BOLT 12] offer, though +/// spontaneous (i.e., keysend) payments are also possible. Incoming payments don't require +/// maintaining any additional state as [`ChannelManager`] can reconstruct the [`PaymentPreimage`] +/// from the [`PaymentSecret`]. Sending payments, however, require tracking in order to retry failed +/// HTLCs. +/// +/// After a payment is initiated, it will appear in [`list_recent_payments`] until a short time +/// after either an [`Event::PaymentSent`] or [`Event::PaymentFailed`] is handled. Failed HTLCs +/// for a payment will be retried according to the payment's [`Retry`] strategy or until +/// [`abandon_payment`] is called. +/// +/// ## BOLT 11 Invoices +/// +/// The [`lightning-invoice`] crate is useful for creating BOLT 11 invoices. Specifically, use the +/// functions in its `utils` module for constructing invoices that are compatible with +/// [`ChannelManager`]. These functions serve as a convenience for building invoices with the +/// [`PaymentHash`] and [`PaymentSecret`] returned from [`create_inbound_payment`]. To provide your +/// own [`PaymentHash`], use [`create_inbound_payment_for_hash`] or the corresponding functions in +/// the [`lightning-invoice`] `utils` module. +/// +/// [`ChannelManager`] generates an [`Event::PaymentClaimable`] once the full payment has been +/// received. Call [`claim_funds`] to release the [`PaymentPreimage`], which in turn will result in +/// an [`Event::PaymentClaimed`]. +/// +/// ``` +/// # use lightning::events::{Event, EventsProvider, PaymentPurpose}; +/// # use lightning::ln::channelmanager::AChannelManager; +/// # +/// # fn example(channel_manager: T) { +/// # let channel_manager = channel_manager.get_cm(); +/// // Or use utils::create_invoice_from_channelmanager +/// let known_payment_hash = match channel_manager.create_inbound_payment( +/// Some(10_000_000), 3600, None +/// ) { +/// Ok((payment_hash, _payment_secret)) => { +/// println!("Creating inbound payment {}", payment_hash); +/// payment_hash +/// }, +/// Err(()) => panic!("Error creating inbound payment"), +/// }; +/// +/// // On the event processing thread +/// channel_manager.process_pending_events(&|event| match event { +/// Event::PaymentClaimable { payment_hash, purpose, .. } => match purpose { +/// PaymentPurpose::InvoicePayment { payment_preimage: Some(payment_preimage), .. } => { +/// assert_eq!(payment_hash, known_payment_hash); +/// println!("Claiming payment {}", payment_hash); +/// channel_manager.claim_funds(payment_preimage); +/// }, +/// PaymentPurpose::InvoicePayment { payment_preimage: None, .. } => { +/// println!("Unknown payment hash: {}", payment_hash); +/// }, +/// PaymentPurpose::SpontaneousPayment(payment_preimage) => { +/// assert_ne!(payment_hash, known_payment_hash); +/// println!("Claiming spontaneous payment {}", payment_hash); +/// channel_manager.claim_funds(payment_preimage); +/// }, +/// }, +/// Event::PaymentClaimed { payment_hash, amount_msat, .. } => { +/// assert_eq!(payment_hash, known_payment_hash); +/// println!("Claimed {} msats", amount_msat); +/// }, +/// // ... +/// # _ => {}, +/// }); +/// # } +/// ``` +/// +/// For paying an invoice, [`lightning-invoice`] provides a `payment` module with convenience +/// functions for use with [`send_payment`]. +/// +/// ``` +/// # use lightning::events::{Event, EventsProvider}; +/// # use lightning::ln::PaymentHash; +/// # use lightning::ln::channelmanager::{AChannelManager, PaymentId, RecentPaymentDetails, RecipientOnionFields, Retry}; +/// # use lightning::routing::router::RouteParameters; +/// # +/// # fn example( +/// # channel_manager: T, payment_hash: PaymentHash, recipient_onion: RecipientOnionFields, +/// # route_params: RouteParameters, retry: Retry +/// # ) { +/// # let channel_manager = channel_manager.get_cm(); +/// // let (payment_hash, recipient_onion, route_params) = +/// // payment::payment_parameters_from_invoice(&invoice); +/// let payment_id = PaymentId([42; 32]); +/// match channel_manager.send_payment( +/// payment_hash, recipient_onion, payment_id, route_params, retry +/// ) { +/// Ok(()) => println!("Sending payment with hash {}", payment_hash), +/// Err(e) => println!("Failed sending payment with hash {}: {:?}", payment_hash, e), +/// } +/// +/// let expected_payment_id = payment_id; +/// let expected_payment_hash = payment_hash; +/// assert!( +/// channel_manager.list_recent_payments().iter().find(|details| matches!( +/// details, +/// RecentPaymentDetails::Pending { +/// payment_id: expected_payment_id, +/// payment_hash: expected_payment_hash, +/// .. +/// } +/// )).is_some() +/// ); +/// +/// // On the event processing thread +/// channel_manager.process_pending_events(&|event| match event { +/// Event::PaymentSent { payment_hash, .. } => println!("Paid {}", payment_hash), +/// Event::PaymentFailed { payment_hash, .. } => println!("Failed paying {}", payment_hash), +/// // ... +/// # _ => {}, +/// }); +/// # } +/// ``` +/// /// # Persistence /// /// Implements [`Writeable`] to write out all channel state to disk. Implies [`peer_disconnected`] for @@ -1474,6 +1592,15 @@ where /// [`create_channel`]: Self::create_channel /// [`close_channel`]: Self::force_close_broadcasting_latest_txn /// [`force_close_broadcasting_latest_txn`]: Self::force_close_broadcasting_latest_txn +/// [BOLT 11]: https://github.com/lightning/bolts/blob/master/11-payment-encoding.md +/// [BOLT 12]: https://github.com/rustyrussell/lightning-rfc/blob/guilt/offers/12-offer-encoding.md +/// [`list_recent_payments`]: Self::list_recent_payments +/// [`abandon_payment`]: Self::abandon_payment +/// [`lightning-invoice`]: https://docs.rs/lightning_invoice/latest/lightning_invoice +/// [`create_inbound_payment`]: Self::create_inbound_payment +/// [`create_inbound_payment_for_hash`]: Self::create_inbound_payment_for_hash +/// [`claim_funds`]: Self::claim_funds +/// [`send_payment`]: Self::send_payment /// [`peer_disconnected`]: msgs::ChannelMessageHandler::peer_disconnected /// [`funding_created`]: msgs::FundingCreated /// [`funding_transaction_generated`]: Self::funding_transaction_generated From 761f09b04c7094d9cf6686efe96c2a22526e82ff Mon Sep 17 00:00:00 2001 From: Jeffrey Czyz Date: Mon, 22 Jan 2024 15:34:27 -0600 Subject: [PATCH 8/9] Add BOLT 12 Offers section to ChannelManager docs --- lightning/src/ln/channelmanager.rs | 103 +++++++++++++++++++++++++++++ lightning/src/offers/offer.rs | 10 +++ 2 files changed, 113 insertions(+) diff --git a/lightning/src/ln/channelmanager.rs b/lightning/src/ln/channelmanager.rs index dc170b652b5..ee2e94c462b 100644 --- a/lightning/src/ln/channelmanager.rs +++ b/lightning/src/ln/channelmanager.rs @@ -1526,6 +1526,105 @@ where /// # } /// ``` /// +/// ## BOLT 12 Offers +/// +/// The [`offers`] module is useful for creating BOLT 12 offers. An [`Offer`] is a precursor to a +/// [`Bolt12Invoice`], which must first be requested by the payer. The interchange of these messages +/// as defined in the specification is handled by [`ChannelManager`] and its implementation of +/// [`OffersMessageHandler`]. However, this only works with an [`Offer`] created using a builder +/// returned by [`create_offer_builder`]. With this approach, BOLT 12 offers and invoices are +/// stateless just as BOLT 11 invoices are. +/// +/// ``` +/// # use lightning::events::{Event, EventsProvider, PaymentPurpose}; +/// # use lightning::ln::channelmanager::AChannelManager; +/// # use lightning::offers::parse::Bolt12SemanticError; +/// # +/// # fn example(channel_manager: T) -> Result<(), Bolt12SemanticError> { +/// # let channel_manager = channel_manager.get_cm(); +/// let offer = channel_manager +/// .create_offer_builder("coffee".to_string())? +/// # ; +/// # // Needed for compiling for c_bindings +/// # let builder: lightning::offers::offer::OfferBuilder<_, _> = offer.into(); +/// # let offer = builder +/// .amount_msats(10_000_000) +/// .build()?; +/// let bech32_offer = offer.to_string(); +/// +/// // On the event processing thread +/// channel_manager.process_pending_events(&|event| match event { +/// Event::PaymentClaimable { payment_hash, purpose, .. } => match purpose { +/// PaymentPurpose::InvoicePayment { payment_preimage: Some(payment_preimage), .. } => { +/// println!("Claiming payment {}", payment_hash); +/// channel_manager.claim_funds(payment_preimage); +/// }, +/// PaymentPurpose::InvoicePayment { payment_preimage: None, .. } => { +/// println!("Unknown payment hash: {}", payment_hash); +/// }, +/// // ... +/// # _ => {}, +/// }, +/// Event::PaymentClaimed { payment_hash, amount_msat, .. } => { +/// println!("Claimed {} msats", amount_msat); +/// }, +/// // ... +/// # _ => {}, +/// }); +/// # Ok(()) +/// # } +/// ``` +/// +/// Use [`pay_for_offer`] to initiated payment, which sends an [`InvoiceRequest`] for an [`Offer`] +/// and pays the [`Bolt12Invoice`] response. In addition to success and failure events, +/// [`ChannelManager`] may also generate an [`Event::InvoiceRequestFailed`]. +/// +/// ``` +/// # use lightning::events::{Event, EventsProvider}; +/// # use lightning::ln::channelmanager::{AChannelManager, PaymentId, RecentPaymentDetails, Retry}; +/// # use lightning::offers::offer::Offer; +/// # +/// # fn example( +/// # channel_manager: T, offer: &Offer, quantity: Option, amount_msats: Option, +/// # payer_note: Option, retry: Retry, max_total_routing_fee_msat: Option +/// # ) { +/// # let channel_manager = channel_manager.get_cm(); +/// let payment_id = PaymentId([42; 32]); +/// match channel_manager.pay_for_offer( +/// offer, quantity, amount_msats, payer_note, payment_id, retry, max_total_routing_fee_msat +/// ) { +/// Ok(()) => println!("Requesting invoice for offer"), +/// Err(e) => println!("Unable to request invoice for offer: {:?}", e), +/// } +/// +/// // First the payment will be waiting on an invoice +/// let expected_payment_id = payment_id; +/// assert!( +/// channel_manager.list_recent_payments().iter().find(|details| matches!( +/// details, +/// RecentPaymentDetails::AwaitingInvoice { payment_id: expected_payment_id } +/// )).is_some() +/// ); +/// +/// // Once the invoice is received, a payment will be sent +/// assert!( +/// channel_manager.list_recent_payments().iter().find(|details| matches!( +/// details, +/// RecentPaymentDetails::Pending { payment_id: expected_payment_id, .. } +/// )).is_some() +/// ); +/// +/// // On the event processing thread +/// channel_manager.process_pending_events(&|event| match event { +/// Event::PaymentSent { payment_id: Some(payment_id), .. } => println!("Paid {}", payment_id), +/// Event::PaymentFailed { payment_id, .. } => println!("Failed paying {}", payment_id), +/// Event::InvoiceRequestFailed { payment_id, .. } => println!("Failed paying {}", payment_id), +/// // ... +/// # _ => {}, +/// }); +/// # } +/// ``` +/// /// # Persistence /// /// Implements [`Writeable`] to write out all channel state to disk. Implies [`peer_disconnected`] for @@ -1601,6 +1700,10 @@ where /// [`create_inbound_payment_for_hash`]: Self::create_inbound_payment_for_hash /// [`claim_funds`]: Self::claim_funds /// [`send_payment`]: Self::send_payment +/// [`offers`]: crate::offers +/// [`create_offer_builder`]: Self::create_offer_builder +/// [`pay_for_offer`]: Self::pay_for_offer +/// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest /// [`peer_disconnected`]: msgs::ChannelMessageHandler::peer_disconnected /// [`funding_created`]: msgs::FundingCreated /// [`funding_transaction_generated`]: Self::funding_transaction_generated diff --git a/lightning/src/offers/offer.rs b/lightning/src/offers/offer.rs index bf5e50deb77..4cb655e9c07 100644 --- a/lightning/src/offers/offer.rs +++ b/lightning/src/offers/offer.rs @@ -459,6 +459,16 @@ for OfferWithDerivedMetadataBuilder<'a> { } } +#[cfg(c_bindings)] +impl<'a> From> +for OfferBuilder<'a, DerivedMetadata, secp256k1::All> { + fn from(builder: OfferWithDerivedMetadataBuilder<'a>) -> Self { + let OfferWithDerivedMetadataBuilder { offer, metadata_strategy, secp_ctx } = builder; + + Self { offer, metadata_strategy, secp_ctx } + } +} + /// An `Offer` is a potentially long-lived proposal for payment of a good or service. /// /// An offer is a precursor to an [`InvoiceRequest`]. A merchant publishes an offer from which a From 998fffb99bfc83b8ab66d4174d235e597ea4494f Mon Sep 17 00:00:00 2001 From: Jeffrey Czyz Date: Tue, 23 Jan 2024 13:01:37 -0600 Subject: [PATCH 9/9] Add BOLT 12 Refunds section to ChannelManager docs --- lightning/src/ln/channelmanager.rs | 99 ++++++++++++++++++++++++++++++ lightning/src/offers/refund.rs | 10 +++ 2 files changed, 109 insertions(+) diff --git a/lightning/src/ln/channelmanager.rs b/lightning/src/ln/channelmanager.rs index ee2e94c462b..9c559909bc7 100644 --- a/lightning/src/ln/channelmanager.rs +++ b/lightning/src/ln/channelmanager.rs @@ -1625,6 +1625,103 @@ where /// # } /// ``` /// +/// ## BOLT 12 Refunds +/// +/// A [`Refund`] is a request for an invoice to be paid. Like *paying* for an [`Offer`], *creating* +/// a [`Refund`] involves maintaining state since it represents a future outbound payment. +/// Therefore, use [`create_refund_builder`] when creating one, otherwise [`ChannelManager`] will +/// refuse to pay any corresponding [`Bolt12Invoice`] that it receives. +/// +/// ``` +/// # use core::time::Duration; +/// # use lightning::events::{Event, EventsProvider}; +/// # use lightning::ln::channelmanager::{AChannelManager, PaymentId, RecentPaymentDetails, Retry}; +/// # use lightning::offers::parse::Bolt12SemanticError; +/// # +/// # fn example( +/// # channel_manager: T, amount_msats: u64, absolute_expiry: Duration, retry: Retry, +/// # max_total_routing_fee_msat: Option +/// # ) -> Result<(), Bolt12SemanticError> { +/// # let channel_manager = channel_manager.get_cm(); +/// let payment_id = PaymentId([42; 32]); +/// let refund = channel_manager +/// .create_refund_builder( +/// "coffee".to_string(), amount_msats, absolute_expiry, payment_id, retry, +/// max_total_routing_fee_msat +/// )? +/// # ; +/// # // Needed for compiling for c_bindings +/// # let builder: lightning::offers::refund::RefundBuilder<_> = refund.into(); +/// # let refund = builder +/// .payer_note("refund for order 1234".to_string()) +/// .build()?; +/// let bech32_refund = refund.to_string(); +/// +/// // First the payment will be waiting on an invoice +/// let expected_payment_id = payment_id; +/// assert!( +/// channel_manager.list_recent_payments().iter().find(|details| matches!( +/// details, +/// RecentPaymentDetails::AwaitingInvoice { payment_id: expected_payment_id } +/// )).is_some() +/// ); +/// +/// // Once the invoice is received, a payment will be sent +/// assert!( +/// channel_manager.list_recent_payments().iter().find(|details| matches!( +/// details, +/// RecentPaymentDetails::Pending { payment_id: expected_payment_id, .. } +/// )).is_some() +/// ); +/// +/// // On the event processing thread +/// channel_manager.process_pending_events(&|event| match event { +/// Event::PaymentSent { payment_id: Some(payment_id), .. } => println!("Paid {}", payment_id), +/// Event::PaymentFailed { payment_id, .. } => println!("Failed paying {}", payment_id), +/// // ... +/// # _ => {}, +/// }); +/// # Ok(()) +/// # } +/// ``` +/// +/// Use [`request_refund_payment`] to send a [`Bolt12Invoice`] for receiving the refund. Similar to +/// *creating* an [`Offer`], this is stateless as it represents an inbound payment. +/// +/// ``` +/// # use lightning::events::{Event, EventsProvider, PaymentPurpose}; +/// # use lightning::ln::channelmanager::AChannelManager; +/// # use lightning::offers::refund::Refund; +/// # +/// # fn example(channel_manager: T, refund: &Refund) { +/// # let channel_manager = channel_manager.get_cm(); +/// match channel_manager.request_refund_payment(refund) { +/// Ok(()) => println!("Requesting payment for refund"), +/// Err(e) => println!("Unable to request payment for refund: {:?}", e), +/// } +/// +/// // On the event processing thread +/// channel_manager.process_pending_events(&|event| match event { +/// Event::PaymentClaimable { payment_hash, purpose, .. } => match purpose { +/// PaymentPurpose::InvoicePayment { payment_preimage: Some(payment_preimage), .. } => { +/// println!("Claiming payment {}", payment_hash); +/// channel_manager.claim_funds(payment_preimage); +/// }, +/// PaymentPurpose::InvoicePayment { payment_preimage: None, .. } => { +/// println!("Unknown payment hash: {}", payment_hash); +/// }, +/// // ... +/// # _ => {}, +/// }, +/// Event::PaymentClaimed { payment_hash, amount_msat, .. } => { +/// println!("Claimed {} msats", amount_msat); +/// }, +/// // ... +/// # _ => {}, +/// }); +/// # } +/// ``` +/// /// # Persistence /// /// Implements [`Writeable`] to write out all channel state to disk. Implies [`peer_disconnected`] for @@ -1704,6 +1801,8 @@ where /// [`create_offer_builder`]: Self::create_offer_builder /// [`pay_for_offer`]: Self::pay_for_offer /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest +/// [`create_refund_builder`]: Self::create_refund_builder +/// [`request_refund_payment`]: Self::request_refund_payment /// [`peer_disconnected`]: msgs::ChannelMessageHandler::peer_disconnected /// [`funding_created`]: msgs::FundingCreated /// [`funding_transaction_generated`]: Self::funding_transaction_generated diff --git a/lightning/src/offers/refund.rs b/lightning/src/offers/refund.rs index 42177960868..5305076bf91 100644 --- a/lightning/src/offers/refund.rs +++ b/lightning/src/offers/refund.rs @@ -375,6 +375,16 @@ for RefundMaybeWithDerivedMetadataBuilder<'a> { } } +#[cfg(c_bindings)] +impl<'a> From> +for RefundBuilder<'a, secp256k1::All> { + fn from(builder: RefundMaybeWithDerivedMetadataBuilder<'a>) -> Self { + let RefundMaybeWithDerivedMetadataBuilder { refund, secp_ctx } = builder; + + Self { refund, secp_ctx } + } +} + /// A `Refund` is a request to send an [`Bolt12Invoice`] without a preceding [`Offer`]. /// /// Typically, after an invoice is paid, the recipient may publish a refund allowing the sender to