BOLT 12 Offers utilities

fuzz/src/onion_message.rs

@@ -14,7 +14,7 @@ use lightning::offers::invoice_request::UnsignedInvoiceRequest;
 use lightning::util::test_channel_signer::TestChannelSigner;
 use lightning::util::logger::Logger;
 use lightning::util::ser::{Readable, Writeable, Writer};
-use lightning::onion_message::{CustomOnionMessageContents, CustomOnionMessageHandler, Destination, MessageRouter, OffersMessage, OffersMessageHandler, OnionMessagePath, OnionMessenger};
+use lightning::onion_message::{CustomOnionMessageHandler, Destination, MessageRouter, OffersMessage, OffersMessageHandler, OnionMessageContents, OnionMessagePath, OnionMessenger, PendingOnionMessage};
 
 use crate::utils::test_logger;
 
@@ -84,7 +84,7 @@ struct TestCustomMessage {}
 const CUSTOM_MESSAGE_TYPE: u64 = 4242;
 const CUSTOM_MESSAGE_CONTENTS: [u8; 32] = [42; 32];
 
-impl CustomOnionMessageContents for TestCustomMessage {
+impl OnionMessageContents for TestCustomMessage {
 	fn tlv_type(&self) -> u64 {
  CUSTOM_MESSAGE_TYPE
 	}
@@ -108,6 +108,9 @@ impl CustomOnionMessageHandler for TestCustomMessageHandler {
  buffer.read_to_end(&mut buf)?;
  return Ok(Some(TestCustomMessage {}))
 	}
+	fn release_pending_custom_messages(&self) -> Vec<PendingOnionMessage<Self::CustomMessage>> {
+ vec![]
+	}
 }
 
 pub struct VecWriter(pub Vec<u8>);
@@ -208,19 +211,6 @@ mod tests {
 
 	#[test]
 	fn test_no_onion_message_breakage() {
- let one_hop_om = "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";
- let logger = TrackingLogger { lines: Mutex::new(HashMap::new()) };
- super::do_test(&::hex::decode(one_hop_om).unwrap(), &logger);
- {
- let log_entries = logger.lines.lock().unwrap();
- assert_eq!(log_entries.get(&("lightning::onion_message::messenger".to_string(),
- "Received an onion message with path_id None and a reply_path".to_string())), Some(&1));
- assert_eq!(log_entries.get(&("lightning::onion_message::messenger".to_string(),
- "Responding to onion message with path_id None".to_string())), Some(&1));
- assert_eq!(log_entries.get(&("lightning::onion_message::messenger".to_string(),
- "Failed responding to onion message with path_id None: TooFewBlindedHops".to_string())), Some(&1));
- }
-
  let two_unblinded_hops_om = "020000000000000000000000000000000000000000000000000000000000000e01055600020000000000000000000000000000000000000000000000000000000000000e0135043304210202020202020202020202020202020202020202020202020202020202020202026d000000000000000000000000000000eb0000000000000000000000000000000000000000000000000000000000000036041096000000000000000000000000000000fd1092202a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000004800000000000000000000000000000000000000000000000000000000000000";
  let logger = TrackingLogger { lines: Mutex::new(HashMap::new()) };
  super::do_test(&::hex::decode(two_unblinded_hops_om).unwrap(), &logger);

lightning/src/blinded_path/mod.rs

@@ -56,15 +56,22 @@ pub struct BlindedHop {
 }
 
 impl BlindedPath {
+	/// Create a one-hop blinded path for a message.
+	pub fn one_hop_for_message<ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification>(
+ recipient_node_id: PublicKey, entropy_source: &ES, secp_ctx: &Secp256k1<T>
+	) -> Result<Self, ()> {
+ Self::new_for_message(&[recipient_node_id], entropy_source, secp_ctx)
+	}
+
 	/// Create a blinded path for an onion message, to be forwarded along `node_pks`. The last node
 	/// pubkey in `node_pks` will be the destination node.
 	///
-	/// Errors if less than two hops are provided or if `node_pk`(s) are invalid.
+	/// Errors if no hops are provided or if `node_pk`(s) are invalid.
 	// TODO: make all payloads the same size with padding + add dummy hops
-	pub fn new_for_message<ES: EntropySource, T: secp256k1::Signing + secp256k1::Verification>
-(node_pks: &[PublicKey], entropy_source: &ES, secp_ctx: &Secp256k1<T>) -> Result<Self, ()>
-	{
- if node_pks.len() < 2 { return Err(()) }
+	pub fn new_for_message<ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification>(
+ node_pks: &[PublicKey], entropy_source: &ES, secp_ctx: &Secp256k1<T>
+) -> Result<Self, ()> {
+ if node_pks.is_empty() { return Err(()) }
  let blinding_secret_bytes = entropy_source.get_secure_random_bytes();
  let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
  let introduction_node_id = node_pks[0];

lightning/src/events/mod.rs

@@ -1846,12 +1846,6 @@ pub trait MessageSendEventsProvider {
 	fn get_and_clear_pending_msg_events(&self) -> Vec<MessageSendEvent>;
 }
 
-/// A trait indicating an object may generate onion messages to send
-pub trait OnionMessageProvider {
-	/// Gets the next pending onion message for the peer with the given node id.
-	fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<msgs::OnionMessage>;
-}
-
 /// A trait indicating an object may generate events.
 ///
 /// Events are processed by passing an [`EventHandler`] to [`process_pending_events`].

lightning/src/ln/channelmanager.rs

@@ -30,6 +30,7 @@ use bitcoin::secp256k1::{SecretKey,PublicKey};
 use bitcoin::secp256k1::Secp256k1;
 use bitcoin::{LockTime, secp256k1, Sequence};
 
+use crate::blinded_path::BlindedPath;
 use crate::chain;
 use crate::chain::{Confirm, ChannelMonitorUpdateStatus, Watch, BestBlock};
 use crate::chain::chaininterface::{BroadcasterInterface, ConfirmationTarget, FeeEstimator, LowerBoundedFeeEstimator};
@@ -55,6 +56,9 @@ use crate::ln::msgs::{ChannelMessageHandler, DecodeError, LightningError};
 use crate::ln::outbound_payment;
 use crate::ln::outbound_payment::{OutboundPayments, PaymentAttempts, PendingOutboundPayment, SendAlongPathArgs};
 use crate::ln::wire::Encode;
+use crate::offers::offer::{DerivedMetadata, OfferBuilder};
+use crate::offers::parse::Bolt12SemanticError;
+use crate::offers::refund::RefundBuilder;
 use crate::sign::{EntropySource, KeysManager, NodeSigner, Recipient, SignerProvider, WriteableEcdsaChannelSigner};
 use crate::util::config::{UserConfig, ChannelConfig, ChannelConfigUpdate};
 use crate::util::wakers::{Future, Notifier};
@@ -4791,6 +4795,10 @@ where
 	/// with the current [`ChannelConfig`].
 	/// * Removing peers which have disconnected but and no longer have any channels.
 	/// * Force-closing and removing channels which have not completed establishment in a timely manner.
+	/// * Forgetting about stale outbound payments, either those that have already been fulfilled
+	/// or those awaiting an invoice that hasn't been delivered in the necessary amount of time.
+	/// The latter is determined using the system clock in `std` and the block time minus two
+	/// hours in `no-std`.
 	///
 	/// Note that this may cause reentrancy through [`chain::Watch::update_channel`] calls or feerate
 	/// estimate fetches.
@@ -5019,7 +5027,18 @@ where
  self.finish_close_channel(shutdown_res);
  }
 
- self.pending_outbound_payments.remove_stale_payments(&self.pending_events);
+ #[cfg(feature = "std")]
+ let duration_since_epoch = std::time::SystemTime::now()
+ .duration_since(std::time::SystemTime::UNIX_EPOCH)
+ .expect("SystemTime::now() should come after SystemTime::UNIX_EPOCH");
+ #[cfg(not(feature = "std"))]
+ let duration_since_epoch = Duration::from_secs(
+ self.highest_seen_timestamp.load(Ordering::Acquire).saturating_sub(7200) as u64
+ );
+
+ self.pending_outbound_payments.remove_stale_payments(
+ duration_since_epoch, &self.pending_events
+ );
 
  // Technically we don't need to do this here, but if we have holding cell entries in a
  // channel that need freeing, it's better to do that here and block a background task
@@ -7108,6 +7127,71 @@ where
  }
 	}
 
+	/// Creates an [`OfferBuilder`] such that the [`Offer`] it builds is recognized by the
+	/// [`ChannelManager`] when handling [`InvoiceRequest`] messages for the offer. The offer will
+	/// not have an expiration unless otherwise set on the builder.
+	///
+	/// Uses a one-hop [`BlindedPath`] for the offer with [`ChannelManager::get_our_node_id`] as the
+	/// introduction node and a derived signing pubkey for recipient privacy. As such, currently,
+	/// the node must be announced. Otherwise, there is no way to find a path to the introduction
+	/// node in order to send the [`InvoiceRequest`].
+	///
+	/// [`Offer`]: crate::offers::offer::Offer
+	/// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
+	pub fn create_offer_builder(
+ &self, description: String
+	) -> OfferBuilder<DerivedMetadata, secp256k1::All> {
+ let node_id = self.get_our_node_id();
+ let expanded_key = &self.inbound_payment_key;
+ let entropy = &*self.entropy_source;
+ let secp_ctx = &self.secp_ctx;
+ let path = self.create_one_hop_blinded_path();
+
+ OfferBuilder::deriving_signing_pubkey(description, node_id, expanded_key, entropy, secp_ctx)
+ .chain_hash(self.chain_hash)
+ .path(path)
+	}
+
+	/// Creates a [`RefundBuilder`] such that the [`Refund`] it builds is recognized by the
+	/// [`ChannelManager`] when handling [`Bolt12Invoice`] messages for the refund. The builder will
+	/// have the provided expiration set. Any changes to the expiration on the returned builder will
+	/// not be honored by [`ChannelManager`].
+	///
+	/// The provided `payment_id` is used to ensure that only one invoice is paid for the refund.
+	///
+	/// Uses a one-hop [`BlindedPath`] for the refund with [`ChannelManager::get_our_node_id`] as
+	/// the introduction node and a derived payer id for sender privacy. As such, currently, the
+	/// node must be announced. Otherwise, there is no way to find a path to the introduction node
+	/// in order to send the [`Bolt12Invoice`].
+	///
+	/// [`Refund`]: crate::offers::refund::Refund
+	/// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
+	pub fn create_refund_builder(
+ &self, description: String, amount_msats: u64, absolute_expiry: Duration,
+ payment_id: PaymentId, retry_strategy: Retry, max_total_routing_fee_msat: Option<u64>
+	) -> Result<RefundBuilder<secp256k1::All>, Bolt12SemanticError> {
+ let node_id = self.get_our_node_id();
+ let expanded_key = &self.inbound_payment_key;
+ let entropy = &*self.entropy_source;
+ let secp_ctx = &self.secp_ctx;
+ let path = self.create_one_hop_blinded_path();
+
+ let builder = RefundBuilder::deriving_payer_id(
+ description, node_id, expanded_key, entropy, secp_ctx, amount_msats, payment_id
+ )?
+ .chain_hash(self.chain_hash)
+ .absolute_expiry(absolute_expiry)
+ .path(path);
+
+ self.pending_outbound_payments
+ .add_new_awaiting_invoice(
+ payment_id, absolute_expiry, retry_strategy, max_total_routing_fee_msat,
+ )
+ .map_err(|_| Bolt12SemanticError::DuplicatePaymentId)?;
+
+ Ok(builder)
+	}
+
 	/// Gets a payment secret and payment hash for use in an invoice given to a third party wishing
 	/// to pay us.
 	///
@@ -7208,6 +7292,14 @@ where
  inbound_payment::get_payment_preimage(payment_hash, payment_secret, &self.inbound_payment_key)
 	}
 
+	/// Creates a one-hop blinded path with [`ChannelManager::get_our_node_id`] as the introduction
+	/// node.
+	fn create_one_hop_blinded_path(&self) -> BlindedPath {
+ let entropy_source = self.entropy_source.deref();
+ let secp_ctx = &self.secp_ctx;
+ BlindedPath::one_hop_for_message(self.get_our_node_id(), entropy_source, secp_ctx).unwrap()
+	}
+
 	/// Gets a fake short channel id for use in receiving [phantom node payments]. These fake scids
 	/// are used when constructing the phantom invoice's route hints.
 	///

lightning/src/ln/msgs.rs

@@ -49,7 +49,7 @@ use core::str::FromStr;
 use crate::io::{self, Cursor, Read};
 use crate::io_extras::read_to_end;
 
-use crate::events::{MessageSendEventsProvider, OnionMessageProvider};
+use crate::events::MessageSendEventsProvider;
 use crate::util::chacha20poly1305rfc::ChaChaPolyReadAdapter;
 use crate::util::logger;
 use crate::util::ser::{LengthReadable, LengthReadableArgs, Readable, ReadableArgs, Writeable, Writer, WithoutLength, FixedLengthReader, HighZeroBytesDroppedBigSize, Hostname, TransactionU16LenLimited, BigSize};
@@ -1497,17 +1497,22 @@ pub trait RoutingMessageHandler : MessageSendEventsProvider {
 	fn provided_init_features(&self, their_node_id: &PublicKey) -> InitFeatures;
 }
 
-/// A trait to describe an object that can receive onion messages.
-pub trait OnionMessageHandler : OnionMessageProvider {
+/// A handler for received [`OnionMessage`]s and for providing generated ones to send.
+pub trait OnionMessageHandler {
 	/// Handle an incoming `onion_message` message from the given peer.
 	fn handle_onion_message(&self, peer_node_id: &PublicKey, msg: &OnionMessage);
+
+	/// Returns the next pending onion message for the peer with the given node id.
+	fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<OnionMessage>;
+
 	/// Called when a connection is established with a peer. Can be used to track which peers
 	/// advertise onion message support and are online.
 	///
 	/// May return an `Err(())` if the features the peer supports are not sufficient to communicate
 	/// with us. Implementors should be somewhat conservative about doing so, however, as other
 	/// message handlers may still wish to communicate with this peer.
 	fn peer_connected(&self, their_node_id: &PublicKey, init: &Init, inbound: bool) -> Result<(), ()>;
+
 	/// Indicates a connection to the peer failed/an existing connection was lost. Allows handlers to
 	/// drop and refuse to forward onion messages to this peer.
 	fn peer_disconnected(&self, their_node_id: &PublicKey);

fuzz/src/onion_message.rs

@@ -14,7 +14,7 @@ use lightning::offers::invoice_request::UnsignedInvoiceRequest;
 use lightning::util::test_channel_signer::TestChannelSigner;
 use lightning::util::logger::Logger;
 use lightning::util::ser::{Readable, Writeable, Writer};
-use lightning::onion_message::{CustomOnionMessageContents, CustomOnionMessageHandler, Destination, MessageRouter, OffersMessage, OffersMessageHandler, OnionMessagePath, OnionMessenger};
+use lightning::onion_message::{CustomOnionMessageHandler, Destination, MessageRouter, OffersMessage, OffersMessageHandler, OnionMessageContents, OnionMessagePath, OnionMessenger, PendingOnionMessage};
 
 use crate::utils::test_logger;
 
@@ -84,7 +84,7 @@ struct TestCustomMessage {}
 const CUSTOM_MESSAGE_TYPE: u64 = 4242;
 const CUSTOM_MESSAGE_CONTENTS: [u8; 32] = [42; 32];
 
-impl CustomOnionMessageContents for TestCustomMessage {
+impl OnionMessageContents for TestCustomMessage {
 	fn tlv_type(&self) -> u64 {
  CUSTOM_MESSAGE_TYPE
 	}
@@ -108,6 +108,9 @@ impl CustomOnionMessageHandler for TestCustomMessageHandler {
  buffer.read_to_end(&mut buf)?;
  return Ok(Some(TestCustomMessage {}))
 	}
+	fn release_pending_custom_messages(&self) -> Vec<PendingOnionMessage<Self::CustomMessage>> {
+ vec![]
+	}
 }
 
 pub struct VecWriter(pub Vec<u8>);
@@ -208,19 +211,6 @@ mod tests {
 
 	#[test]
 	fn test_no_onion_message_breakage() {
- let one_hop_om = "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";
- let logger = TrackingLogger { lines: Mutex::new(HashMap::new()) };
- super::do_test(&::hex::decode(one_hop_om).unwrap(), &logger);
- {
- let log_entries = logger.lines.lock().unwrap();
- assert_eq!(log_entries.get(&("lightning::onion_message::messenger".to_string(),
- "Received an onion message with path_id None and a reply_path".to_string())), Some(&1));
- assert_eq!(log_entries.get(&("lightning::onion_message::messenger".to_string(),
- "Responding to onion message with path_id None".to_string())), Some(&1));
- assert_eq!(log_entries.get(&("lightning::onion_message::messenger".to_string(),
- "Failed responding to onion message with path_id None: TooFewBlindedHops".to_string())), Some(&1));
- }
-
  let two_unblinded_hops_om = "020000000000000000000000000000000000000000000000000000000000000e01055600020000000000000000000000000000000000000000000000000000000000000e0135043304210202020202020202020202020202020202020202020202020202020202020202026d000000000000000000000000000000eb0000000000000000000000000000000000000000000000000000000000000036041096000000000000000000000000000000fd1092202a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000004800000000000000000000000000000000000000000000000000000000000000";
  let logger = TrackingLogger { lines: Mutex::new(HashMap::new()) };
  super::do_test(&::hex::decode(two_unblinded_hops_om).unwrap(), &logger);

lightning/src/blinded_path/mod.rs

@@ -56,15 +56,22 @@ pub struct BlindedHop {
 }
 
 impl BlindedPath {
+	/// Create a one-hop blinded path for a message.
+	pub fn one_hop_for_message<ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification>(
+ recipient_node_id: PublicKey, entropy_source: &ES, secp_ctx: &Secp256k1<T>
+	) -> Result<Self, ()> {
+ Self::new_for_message(&[recipient_node_id], entropy_source, secp_ctx)
+	}
+
 	/// Create a blinded path for an onion message, to be forwarded along `node_pks`. The last node
 	/// pubkey in `node_pks` will be the destination node.
 	///
-	/// Errors if less than two hops are provided or if `node_pk`(s) are invalid.
+	/// Errors if no hops are provided or if `node_pk`(s) are invalid.
 	// TODO: make all payloads the same size with padding + add dummy hops
-	pub fn new_for_message<ES: EntropySource, T: secp256k1::Signing + secp256k1::Verification>
-(node_pks: &[PublicKey], entropy_source: &ES, secp_ctx: &Secp256k1<T>) -> Result<Self, ()>
-	{
- if node_pks.len() < 2 { return Err(()) }
+	pub fn new_for_message<ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification>(
+ node_pks: &[PublicKey], entropy_source: &ES, secp_ctx: &Secp256k1<T>
+) -> Result<Self, ()> {
+ if node_pks.is_empty() { return Err(()) }
  let blinding_secret_bytes = entropy_source.get_secure_random_bytes();
  let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
  let introduction_node_id = node_pks[0];

lightning/src/events/mod.rs

@@ -1846,12 +1846,6 @@ pub trait MessageSendEventsProvider {
 	fn get_and_clear_pending_msg_events(&self) -> Vec<MessageSendEvent>;
 }
 
-/// A trait indicating an object may generate onion messages to send
-pub trait OnionMessageProvider {
-	/// Gets the next pending onion message for the peer with the given node id.
-	fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<msgs::OnionMessage>;
-}
-
 /// A trait indicating an object may generate events.
 ///
 /// Events are processed by passing an [`EventHandler`] to [`process_pending_events`].

lightning/src/ln/channelmanager.rs

@@ -30,6 +30,7 @@ use bitcoin::secp256k1::{SecretKey,PublicKey};
 use bitcoin::secp256k1::Secp256k1;
 use bitcoin::{LockTime, secp256k1, Sequence};
 
+use crate::blinded_path::BlindedPath;
 use crate::chain;
 use crate::chain::{Confirm, ChannelMonitorUpdateStatus, Watch, BestBlock};
 use crate::chain::chaininterface::{BroadcasterInterface, ConfirmationTarget, FeeEstimator, LowerBoundedFeeEstimator};
@@ -55,6 +56,9 @@ use crate::ln::msgs::{ChannelMessageHandler, DecodeError, LightningError};
 use crate::ln::outbound_payment;
 use crate::ln::outbound_payment::{OutboundPayments, PaymentAttempts, PendingOutboundPayment, SendAlongPathArgs};
 use crate::ln::wire::Encode;
+use crate::offers::offer::{DerivedMetadata, OfferBuilder};
+use crate::offers::parse::Bolt12SemanticError;
+use crate::offers::refund::RefundBuilder;
 use crate::sign::{EntropySource, KeysManager, NodeSigner, Recipient, SignerProvider, WriteableEcdsaChannelSigner};
 use crate::util::config::{UserConfig, ChannelConfig, ChannelConfigUpdate};
 use crate::util::wakers::{Future, Notifier};
@@ -4791,6 +4795,10 @@ where
 	/// with the current [`ChannelConfig`].
 	/// * Removing peers which have disconnected but and no longer have any channels.
 	/// * Force-closing and removing channels which have not completed establishment in a timely manner.
+	/// * Forgetting about stale outbound payments, either those that have already been fulfilled
+	/// or those awaiting an invoice that hasn't been delivered in the necessary amount of time.
+	/// The latter is determined using the system clock in `std` and the block time minus two
+	/// hours in `no-std`.
 	///
 	/// Note that this may cause reentrancy through [`chain::Watch::update_channel`] calls or feerate
 	/// estimate fetches.
@@ -5019,7 +5027,18 @@ where
  self.finish_close_channel(shutdown_res);
  }
 
- self.pending_outbound_payments.remove_stale_payments(&self.pending_events);
+ #[cfg(feature = "std")]
+ let duration_since_epoch = std::time::SystemTime::now()
+ .duration_since(std::time::SystemTime::UNIX_EPOCH)
+ .expect("SystemTime::now() should come after SystemTime::UNIX_EPOCH");
+ #[cfg(not(feature = "std"))]
+ let duration_since_epoch = Duration::from_secs(
+ self.highest_seen_timestamp.load(Ordering::Acquire).saturating_sub(7200) as u64
+ );
+
+ self.pending_outbound_payments.remove_stale_payments(
+ duration_since_epoch, &self.pending_events
+ );
 
  // Technically we don't need to do this here, but if we have holding cell entries in a
  // channel that need freeing, it's better to do that here and block a background task
@@ -7108,6 +7127,71 @@ where
  }
 	}
 
+	/// Creates an [`OfferBuilder`] such that the [`Offer`] it builds is recognized by the
+	/// [`ChannelManager`] when handling [`InvoiceRequest`] messages for the offer. The offer will
+	/// not have an expiration unless otherwise set on the builder.
+	///
+	/// Uses a one-hop [`BlindedPath`] for the offer with [`ChannelManager::get_our_node_id`] as the
+	/// introduction node and a derived signing pubkey for recipient privacy. As such, currently,
+	/// the node must be announced. Otherwise, there is no way to find a path to the introduction
+	/// node in order to send the [`InvoiceRequest`].
+	///
+	/// [`Offer`]: crate::offers::offer::Offer
+	/// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
+	pub fn create_offer_builder(
+ &self, description: String
+	) -> OfferBuilder<DerivedMetadata, secp256k1::All> {
+ let node_id = self.get_our_node_id();
+ let expanded_key = &self.inbound_payment_key;
+ let entropy = &*self.entropy_source;
+ let secp_ctx = &self.secp_ctx;
+ let path = self.create_one_hop_blinded_path();
+
+ OfferBuilder::deriving_signing_pubkey(description, node_id, expanded_key, entropy, secp_ctx)
+ .chain_hash(self.chain_hash)
+ .path(path)
+	}
+
+	/// Creates a [`RefundBuilder`] such that the [`Refund`] it builds is recognized by the
+	/// [`ChannelManager`] when handling [`Bolt12Invoice`] messages for the refund. The builder will
+	/// have the provided expiration set. Any changes to the expiration on the returned builder will
+	/// not be honored by [`ChannelManager`].
+	///
+	/// The provided `payment_id` is used to ensure that only one invoice is paid for the refund.
+	///
+	/// Uses a one-hop [`BlindedPath`] for the refund with [`ChannelManager::get_our_node_id`] as
+	/// the introduction node and a derived payer id for sender privacy. As such, currently, the
+	/// node must be announced. Otherwise, there is no way to find a path to the introduction node
+	/// in order to send the [`Bolt12Invoice`].
+	///
+	/// [`Refund`]: crate::offers::refund::Refund
+	/// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
+	pub fn create_refund_builder(
+ &self, description: String, amount_msats: u64, absolute_expiry: Duration,
+ payment_id: PaymentId, retry_strategy: Retry, max_total_routing_fee_msat: Option<u64>
+	) -> Result<RefundBuilder<secp256k1::All>, Bolt12SemanticError> {
+ let node_id = self.get_our_node_id();
+ let expanded_key = &self.inbound_payment_key;
+ let entropy = &*self.entropy_source;
+ let secp_ctx = &self.secp_ctx;
+ let path = self.create_one_hop_blinded_path();
+
+ let builder = RefundBuilder::deriving_payer_id(
+ description, node_id, expanded_key, entropy, secp_ctx, amount_msats, payment_id
+ )?
+ .chain_hash(self.chain_hash)
+ .absolute_expiry(absolute_expiry)
+ .path(path);
+
+ self.pending_outbound_payments
+ .add_new_awaiting_invoice(
+ payment_id, absolute_expiry, retry_strategy, max_total_routing_fee_msat,
+ )
+ .map_err(|_| Bolt12SemanticError::DuplicatePaymentId)?;
+
+ Ok(builder)
+	}
+
 	/// Gets a payment secret and payment hash for use in an invoice given to a third party wishing
 	/// to pay us.
 	///
@@ -7208,6 +7292,14 @@ where
  inbound_payment::get_payment_preimage(payment_hash, payment_secret, &self.inbound_payment_key)
 	}
 
+	/// Creates a one-hop blinded path with [`ChannelManager::get_our_node_id`] as the introduction
+	/// node.
+	fn create_one_hop_blinded_path(&self) -> BlindedPath {
+ let entropy_source = self.entropy_source.deref();
+ let secp_ctx = &self.secp_ctx;
+ BlindedPath::one_hop_for_message(self.get_our_node_id(), entropy_source, secp_ctx).unwrap()
+	}
+
 	/// Gets a fake short channel id for use in receiving [phantom node payments]. These fake scids
 	/// are used when constructing the phantom invoice's route hints.
 	///

lightning/src/ln/msgs.rs

@@ -49,7 +49,7 @@ use core::str::FromStr;
 use crate::io::{self, Cursor, Read};
 use crate::io_extras::read_to_end;
 
-use crate::events::{MessageSendEventsProvider, OnionMessageProvider};
+use crate::events::MessageSendEventsProvider;
 use crate::util::chacha20poly1305rfc::ChaChaPolyReadAdapter;
 use crate::util::logger;
 use crate::util::ser::{LengthReadable, LengthReadableArgs, Readable, ReadableArgs, Writeable, Writer, WithoutLength, FixedLengthReader, HighZeroBytesDroppedBigSize, Hostname, TransactionU16LenLimited, BigSize};
@@ -1497,17 +1497,22 @@ pub trait RoutingMessageHandler : MessageSendEventsProvider {
 	fn provided_init_features(&self, their_node_id: &PublicKey) -> InitFeatures;
 }
 
-/// A trait to describe an object that can receive onion messages.
-pub trait OnionMessageHandler : OnionMessageProvider {
+/// A handler for received [`OnionMessage`]s and for providing generated ones to send.
+pub trait OnionMessageHandler {
 	/// Handle an incoming `onion_message` message from the given peer.
 	fn handle_onion_message(&self, peer_node_id: &PublicKey, msg: &OnionMessage);
+
+	/// Returns the next pending onion message for the peer with the given node id.
+	fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<OnionMessage>;
+
 	/// Called when a connection is established with a peer. Can be used to track which peers
 	/// advertise onion message support and are online.
 	///
 	/// May return an `Err(())` if the features the peer supports are not sufficient to communicate
 	/// with us. Implementors should be somewhat conservative about doing so, however, as other
 	/// message handlers may still wish to communicate with this peer.
 	fn peer_connected(&self, their_node_id: &PublicKey, init: &Init, inbound: bool) -> Result<(), ()>;
+
 	/// Indicates a connection to the peer failed/an existing connection was lost. Allows handlers to
 	/// drop and refuse to forward onion messages to this peer.
 	fn peer_disconnected(&self, their_node_id: &PublicKey);

fuzz/src/onion_message.rs

@@ -14,7 +14,7 @@ use lightning::offers::invoice_request::UnsignedInvoiceRequest;
 use lightning::util::test_channel_signer::TestChannelSigner;
 use lightning::util::logger::Logger;
 use lightning::util::ser::{Readable, Writeable, Writer};
-use lightning::onion_message::{CustomOnionMessageContents, CustomOnionMessageHandler, Destination, MessageRouter, OffersMessage, OffersMessageHandler, OnionMessagePath, OnionMessenger};
+use lightning::onion_message::{CustomOnionMessageHandler, Destination, MessageRouter, OffersMessage, OffersMessageHandler, OnionMessageContents, OnionMessagePath, OnionMessenger, PendingOnionMessage};
 
 use crate::utils::test_logger;
 
@@ -84,7 +84,7 @@ struct TestCustomMessage {}
 const CUSTOM_MESSAGE_TYPE: u64 = 4242;
 const CUSTOM_MESSAGE_CONTENTS: [u8; 32] = [42; 32];
 
-impl CustomOnionMessageContents for TestCustomMessage {
+impl OnionMessageContents for TestCustomMessage {
 	fn tlv_type(&self) -> u64 {
  CUSTOM_MESSAGE_TYPE
 	}
@@ -108,6 +108,9 @@ impl CustomOnionMessageHandler for TestCustomMessageHandler {
  buffer.read_to_end(&mut buf)?;
  return Ok(Some(TestCustomMessage {}))
 	}
+	fn release_pending_custom_messages(&self) -> Vec<PendingOnionMessage<Self::CustomMessage>> {
+ vec![]
+	}
 }
 
 pub struct VecWriter(pub Vec<u8>);
@@ -208,19 +211,6 @@ mod tests {
 
 	#[test]
 	fn test_no_onion_message_breakage() {
- let one_hop_om = "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";
- let logger = TrackingLogger { lines: Mutex::new(HashMap::new()) };
- super::do_test(&::hex::decode(one_hop_om).unwrap(), &logger);
- {
- let log_entries = logger.lines.lock().unwrap();
- assert_eq!(log_entries.get(&("lightning::onion_message::messenger".to_string(),
- "Received an onion message with path_id None and a reply_path".to_string())), Some(&1));
- assert_eq!(log_entries.get(&("lightning::onion_message::messenger".to_string(),
- "Responding to onion message with path_id None".to_string())), Some(&1));
- assert_eq!(log_entries.get(&("lightning::onion_message::messenger".to_string(),
- "Failed responding to onion message with path_id None: TooFewBlindedHops".to_string())), Some(&1));
- }
-
  let two_unblinded_hops_om = "020000000000000000000000000000000000000000000000000000000000000e01055600020000000000000000000000000000000000000000000000000000000000000e0135043304210202020202020202020202020202020202020202020202020202020202020202026d000000000000000000000000000000eb0000000000000000000000000000000000000000000000000000000000000036041096000000000000000000000000000000fd1092202a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000004800000000000000000000000000000000000000000000000000000000000000";
  let logger = TrackingLogger { lines: Mutex::new(HashMap::new()) };
  super::do_test(&::hex::decode(two_unblinded_hops_om).unwrap(), &logger);

lightning/src/blinded_path/mod.rs

@@ -56,15 +56,22 @@ pub struct BlindedHop {
 }
 
 impl BlindedPath {
+	/// Create a one-hop blinded path for a message.
+	pub fn one_hop_for_message<ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification>(
+ recipient_node_id: PublicKey, entropy_source: &ES, secp_ctx: &Secp256k1<T>
+	) -> Result<Self, ()> {
+ Self::new_for_message(&[recipient_node_id], entropy_source, secp_ctx)
+	}
+
 	/// Create a blinded path for an onion message, to be forwarded along `node_pks`. The last node
 	/// pubkey in `node_pks` will be the destination node.
 	///
-	/// Errors if less than two hops are provided or if `node_pk`(s) are invalid.
+	/// Errors if no hops are provided or if `node_pk`(s) are invalid.
 	// TODO: make all payloads the same size with padding + add dummy hops
-	pub fn new_for_message<ES: EntropySource, T: secp256k1::Signing + secp256k1::Verification>
-(node_pks: &[PublicKey], entropy_source: &ES, secp_ctx: &Secp256k1<T>) -> Result<Self, ()>
-	{
- if node_pks.len() < 2 { return Err(()) }
+	pub fn new_for_message<ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification>(
+ node_pks: &[PublicKey], entropy_source: &ES, secp_ctx: &Secp256k1<T>
+) -> Result<Self, ()> {
+ if node_pks.is_empty() { return Err(()) }
  let blinding_secret_bytes = entropy_source.get_secure_random_bytes();
  let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
  let introduction_node_id = node_pks[0];

lightning/src/events/mod.rs

@@ -1846,12 +1846,6 @@ pub trait MessageSendEventsProvider {
 	fn get_and_clear_pending_msg_events(&self) -> Vec<MessageSendEvent>;
 }
 
-/// A trait indicating an object may generate onion messages to send
-pub trait OnionMessageProvider {
-	/// Gets the next pending onion message for the peer with the given node id.
-	fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<msgs::OnionMessage>;
-}
-
 /// A trait indicating an object may generate events.
 ///
 /// Events are processed by passing an [`EventHandler`] to [`process_pending_events`].

lightning/src/ln/channelmanager.rs

@@ -30,6 +30,7 @@ use bitcoin::secp256k1::{SecretKey,PublicKey};
 use bitcoin::secp256k1::Secp256k1;
 use bitcoin::{LockTime, secp256k1, Sequence};
 
+use crate::blinded_path::BlindedPath;
 use crate::chain;
 use crate::chain::{Confirm, ChannelMonitorUpdateStatus, Watch, BestBlock};
 use crate::chain::chaininterface::{BroadcasterInterface, ConfirmationTarget, FeeEstimator, LowerBoundedFeeEstimator};
@@ -55,6 +56,9 @@ use crate::ln::msgs::{ChannelMessageHandler, DecodeError, LightningError};
 use crate::ln::outbound_payment;
 use crate::ln::outbound_payment::{OutboundPayments, PaymentAttempts, PendingOutboundPayment, SendAlongPathArgs};
 use crate::ln::wire::Encode;
+use crate::offers::offer::{DerivedMetadata, OfferBuilder};
+use crate::offers::parse::Bolt12SemanticError;
+use crate::offers::refund::RefundBuilder;
 use crate::sign::{EntropySource, KeysManager, NodeSigner, Recipient, SignerProvider, WriteableEcdsaChannelSigner};
 use crate::util::config::{UserConfig, ChannelConfig, ChannelConfigUpdate};
 use crate::util::wakers::{Future, Notifier};
@@ -4791,6 +4795,10 @@ where
 	/// with the current [`ChannelConfig`].
 	/// * Removing peers which have disconnected but and no longer have any channels.
 	/// * Force-closing and removing channels which have not completed establishment in a timely manner.
+	/// * Forgetting about stale outbound payments, either those that have already been fulfilled
+	/// or those awaiting an invoice that hasn't been delivered in the necessary amount of time.
+	/// The latter is determined using the system clock in `std` and the block time minus two
+	/// hours in `no-std`.
 	///
 	/// Note that this may cause reentrancy through [`chain::Watch::update_channel`] calls or feerate
 	/// estimate fetches.
@@ -5019,7 +5027,18 @@ where
  self.finish_close_channel(shutdown_res);
  }
 
- self.pending_outbound_payments.remove_stale_payments(&self.pending_events);
+ #[cfg(feature = "std")]
+ let duration_since_epoch = std::time::SystemTime::now()
+ .duration_since(std::time::SystemTime::UNIX_EPOCH)
+ .expect("SystemTime::now() should come after SystemTime::UNIX_EPOCH");
+ #[cfg(not(feature = "std"))]
+ let duration_since_epoch = Duration::from_secs(
+ self.highest_seen_timestamp.load(Ordering::Acquire).saturating_sub(7200) as u64
+ );
+
+ self.pending_outbound_payments.remove_stale_payments(
+ duration_since_epoch, &self.pending_events
+ );
 
  // Technically we don't need to do this here, but if we have holding cell entries in a
  // channel that need freeing, it's better to do that here and block a background task
@@ -7108,6 +7127,71 @@ where
  }
 	}
 
+	/// Creates an [`OfferBuilder`] such that the [`Offer`] it builds is recognized by the
+	/// [`ChannelManager`] when handling [`InvoiceRequest`] messages for the offer. The offer will
+	/// not have an expiration unless otherwise set on the builder.
+	///
+	/// Uses a one-hop [`BlindedPath`] for the offer with [`ChannelManager::get_our_node_id`] as the
+	/// introduction node and a derived signing pubkey for recipient privacy. As such, currently,
+	/// the node must be announced. Otherwise, there is no way to find a path to the introduction
+	/// node in order to send the [`InvoiceRequest`].
+	///
+	/// [`Offer`]: crate::offers::offer::Offer
+	/// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
+	pub fn create_offer_builder(
+ &self, description: String
+	) -> OfferBuilder<DerivedMetadata, secp256k1::All> {
+ let node_id = self.get_our_node_id();
+ let expanded_key = &self.inbound_payment_key;
+ let entropy = &*self.entropy_source;
+ let secp_ctx = &self.secp_ctx;
+ let path = self.create_one_hop_blinded_path();
+
+ OfferBuilder::deriving_signing_pubkey(description, node_id, expanded_key, entropy, secp_ctx)
+ .chain_hash(self.chain_hash)
+ .path(path)
+	}
+
+	/// Creates a [`RefundBuilder`] such that the [`Refund`] it builds is recognized by the
+	/// [`ChannelManager`] when handling [`Bolt12Invoice`] messages for the refund. The builder will
+	/// have the provided expiration set. Any changes to the expiration on the returned builder will
+	/// not be honored by [`ChannelManager`].
+	///
+	/// The provided `payment_id` is used to ensure that only one invoice is paid for the refund.
+	///
+	/// Uses a one-hop [`BlindedPath`] for the refund with [`ChannelManager::get_our_node_id`] as
+	/// the introduction node and a derived payer id for sender privacy. As such, currently, the
+	/// node must be announced. Otherwise, there is no way to find a path to the introduction node
+	/// in order to send the [`Bolt12Invoice`].
+	///
+	/// [`Refund`]: crate::offers::refund::Refund
+	/// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
+	pub fn create_refund_builder(
+ &self, description: String, amount_msats: u64, absolute_expiry: Duration,
+ payment_id: PaymentId, retry_strategy: Retry, max_total_routing_fee_msat: Option<u64>
+	) -> Result<RefundBuilder<secp256k1::All>, Bolt12SemanticError> {
+ let node_id = self.get_our_node_id();
+ let expanded_key = &self.inbound_payment_key;
+ let entropy = &*self.entropy_source;
+ let secp_ctx = &self.secp_ctx;
+ let path = self.create_one_hop_blinded_path();
+
+ let builder = RefundBuilder::deriving_payer_id(
+ description, node_id, expanded_key, entropy, secp_ctx, amount_msats, payment_id
+ )?
+ .chain_hash(self.chain_hash)
+ .absolute_expiry(absolute_expiry)
+ .path(path);
+
+ self.pending_outbound_payments
+ .add_new_awaiting_invoice(
+ payment_id, absolute_expiry, retry_strategy, max_total_routing_fee_msat,
+ )
+ .map_err(|_| Bolt12SemanticError::DuplicatePaymentId)?;
+
+ Ok(builder)
+	}
+
 	/// Gets a payment secret and payment hash for use in an invoice given to a third party wishing
 	/// to pay us.
 	///
@@ -7208,6 +7292,14 @@ where
  inbound_payment::get_payment_preimage(payment_hash, payment_secret, &self.inbound_payment_key)
 	}
 
+	/// Creates a one-hop blinded path with [`ChannelManager::get_our_node_id`] as the introduction
+	/// node.
+	fn create_one_hop_blinded_path(&self) -> BlindedPath {
+ let entropy_source = self.entropy_source.deref();
+ let secp_ctx = &self.secp_ctx;
+ BlindedPath::one_hop_for_message(self.get_our_node_id(), entropy_source, secp_ctx).unwrap()
+	}
+
 	/// Gets a fake short channel id for use in receiving [phantom node payments]. These fake scids
 	/// are used when constructing the phantom invoice's route hints.
 	///

lightning/src/ln/msgs.rs

@@ -49,7 +49,7 @@ use core::str::FromStr;
 use crate::io::{self, Cursor, Read};
 use crate::io_extras::read_to_end;
 
-use crate::events::{MessageSendEventsProvider, OnionMessageProvider};
+use crate::events::MessageSendEventsProvider;
 use crate::util::chacha20poly1305rfc::ChaChaPolyReadAdapter;
 use crate::util::logger;
 use crate::util::ser::{LengthReadable, LengthReadableArgs, Readable, ReadableArgs, Writeable, Writer, WithoutLength, FixedLengthReader, HighZeroBytesDroppedBigSize, Hostname, TransactionU16LenLimited, BigSize};
@@ -1497,17 +1497,22 @@ pub trait RoutingMessageHandler : MessageSendEventsProvider {
 	fn provided_init_features(&self, their_node_id: &PublicKey) -> InitFeatures;
 }
 
-/// A trait to describe an object that can receive onion messages.
-pub trait OnionMessageHandler : OnionMessageProvider {
+/// A handler for received [`OnionMessage`]s and for providing generated ones to send.
+pub trait OnionMessageHandler {
 	/// Handle an incoming `onion_message` message from the given peer.
 	fn handle_onion_message(&self, peer_node_id: &PublicKey, msg: &OnionMessage);
+
+	/// Returns the next pending onion message for the peer with the given node id.
+	fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<OnionMessage>;
+
 	/// Called when a connection is established with a peer. Can be used to track which peers
 	/// advertise onion message support and are online.
 	///
 	/// May return an `Err(())` if the features the peer supports are not sufficient to communicate
 	/// with us. Implementors should be somewhat conservative about doing so, however, as other
 	/// message handlers may still wish to communicate with this peer.
 	fn peer_connected(&self, their_node_id: &PublicKey, init: &Init, inbound: bool) -> Result<(), ()>;
+
 	/// Indicates a connection to the peer failed/an existing connection was lost. Allows handlers to
 	/// drop and refuse to forward onion messages to this peer.
 	fn peer_disconnected(&self, their_node_id: &PublicKey);

fuzz/src/onion_message.rs

@@ -14,7 +14,7 @@ use lightning::offers::invoice_request::UnsignedInvoiceRequest;
 use lightning::util::test_channel_signer::TestChannelSigner;
 use lightning::util::logger::Logger;
 use lightning::util::ser::{Readable, Writeable, Writer};
-use lightning::onion_message::{CustomOnionMessageContents, CustomOnionMessageHandler, Destination, MessageRouter, OffersMessage, OffersMessageHandler, OnionMessagePath, OnionMessenger};
+use lightning::onion_message::{CustomOnionMessageHandler, Destination, MessageRouter, OffersMessage, OffersMessageHandler, OnionMessageContents, OnionMessagePath, OnionMessenger, PendingOnionMessage};
 
 use crate::utils::test_logger;
 
@@ -84,7 +84,7 @@ struct TestCustomMessage {}
 const CUSTOM_MESSAGE_TYPE: u64 = 4242;
 const CUSTOM_MESSAGE_CONTENTS: [u8; 32] = [42; 32];
 
-impl CustomOnionMessageContents for TestCustomMessage {
+impl OnionMessageContents for TestCustomMessage {
 	fn tlv_type(&self) -> u64 {
  CUSTOM_MESSAGE_TYPE
 	}
@@ -108,6 +108,9 @@ impl CustomOnionMessageHandler for TestCustomMessageHandler {
  buffer.read_to_end(&mut buf)?;
  return Ok(Some(TestCustomMessage {}))
 	}
+	fn release_pending_custom_messages(&self) -> Vec<PendingOnionMessage<Self::CustomMessage>> {
+ vec![]
+	}
 }
 
 pub struct VecWriter(pub Vec<u8>);
@@ -208,19 +211,6 @@ mod tests {
 
 	#[test]
 	fn test_no_onion_message_breakage() {
- let one_hop_om = "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";
- let logger = TrackingLogger { lines: Mutex::new(HashMap::new()) };
- super::do_test(&::hex::decode(one_hop_om).unwrap(), &logger);
- {
- let log_entries = logger.lines.lock().unwrap();
- assert_eq!(log_entries.get(&("lightning::onion_message::messenger".to_string(),
- "Received an onion message with path_id None and a reply_path".to_string())), Some(&1));
- assert_eq!(log_entries.get(&("lightning::onion_message::messenger".to_string(),
- "Responding to onion message with path_id None".to_string())), Some(&1));
- assert_eq!(log_entries.get(&("lightning::onion_message::messenger".to_string(),
- "Failed responding to onion message with path_id None: TooFewBlindedHops".to_string())), Some(&1));
- }
-
  let two_unblinded_hops_om = "020000000000000000000000000000000000000000000000000000000000000e01055600020000000000000000000000000000000000000000000000000000000000000e0135043304210202020202020202020202020202020202020202020202020202020202020202026d000000000000000000000000000000eb0000000000000000000000000000000000000000000000000000000000000036041096000000000000000000000000000000fd1092202a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000004800000000000000000000000000000000000000000000000000000000000000";
  let logger = TrackingLogger { lines: Mutex::new(HashMap::new()) };
  super::do_test(&::hex::decode(two_unblinded_hops_om).unwrap(), &logger);

lightning/src/blinded_path/mod.rs

@@ -56,15 +56,22 @@ pub struct BlindedHop {
 }
 
 impl BlindedPath {
+	/// Create a one-hop blinded path for a message.
+	pub fn one_hop_for_message<ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification>(
+ recipient_node_id: PublicKey, entropy_source: &ES, secp_ctx: &Secp256k1<T>
+	) -> Result<Self, ()> {
+ Self::new_for_message(&[recipient_node_id], entropy_source, secp_ctx)
+	}
+
 	/// Create a blinded path for an onion message, to be forwarded along `node_pks`. The last node
 	/// pubkey in `node_pks` will be the destination node.
 	///
-	/// Errors if less than two hops are provided or if `node_pk`(s) are invalid.
+	/// Errors if no hops are provided or if `node_pk`(s) are invalid.
 	// TODO: make all payloads the same size with padding + add dummy hops
-	pub fn new_for_message<ES: EntropySource, T: secp256k1::Signing + secp256k1::Verification>
-(node_pks: &[PublicKey], entropy_source: &ES, secp_ctx: &Secp256k1<T>) -> Result<Self, ()>
-	{
- if node_pks.len() < 2 { return Err(()) }
+	pub fn new_for_message<ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification>(
+ node_pks: &[PublicKey], entropy_source: &ES, secp_ctx: &Secp256k1<T>
+) -> Result<Self, ()> {
+ if node_pks.is_empty() { return Err(()) }
  let blinding_secret_bytes = entropy_source.get_secure_random_bytes();
  let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
  let introduction_node_id = node_pks[0];

lightning/src/events/mod.rs

@@ -1846,12 +1846,6 @@ pub trait MessageSendEventsProvider {
 	fn get_and_clear_pending_msg_events(&self) -> Vec<MessageSendEvent>;
 }
 
-/// A trait indicating an object may generate onion messages to send
-pub trait OnionMessageProvider {
-	/// Gets the next pending onion message for the peer with the given node id.
-	fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<msgs::OnionMessage>;
-}
-
 /// A trait indicating an object may generate events.
 ///
 /// Events are processed by passing an [`EventHandler`] to [`process_pending_events`].

lightning/src/ln/channelmanager.rs

@@ -30,6 +30,7 @@ use bitcoin::secp256k1::{SecretKey,PublicKey};
 use bitcoin::secp256k1::Secp256k1;
 use bitcoin::{LockTime, secp256k1, Sequence};
 
+use crate::blinded_path::BlindedPath;
 use crate::chain;
 use crate::chain::{Confirm, ChannelMonitorUpdateStatus, Watch, BestBlock};
 use crate::chain::chaininterface::{BroadcasterInterface, ConfirmationTarget, FeeEstimator, LowerBoundedFeeEstimator};
@@ -55,6 +56,9 @@ use crate::ln::msgs::{ChannelMessageHandler, DecodeError, LightningError};
 use crate::ln::outbound_payment;
 use crate::ln::outbound_payment::{OutboundPayments, PaymentAttempts, PendingOutboundPayment, SendAlongPathArgs};
 use crate::ln::wire::Encode;
+use crate::offers::offer::{DerivedMetadata, OfferBuilder};
+use crate::offers::parse::Bolt12SemanticError;
+use crate::offers::refund::RefundBuilder;
 use crate::sign::{EntropySource, KeysManager, NodeSigner, Recipient, SignerProvider, WriteableEcdsaChannelSigner};
 use crate::util::config::{UserConfig, ChannelConfig, ChannelConfigUpdate};
 use crate::util::wakers::{Future, Notifier};
@@ -4791,6 +4795,10 @@ where
 	/// with the current [`ChannelConfig`].
 	/// * Removing peers which have disconnected but and no longer have any channels.
 	/// * Force-closing and removing channels which have not completed establishment in a timely manner.
+	/// * Forgetting about stale outbound payments, either those that have already been fulfilled
+	/// or those awaiting an invoice that hasn't been delivered in the necessary amount of time.
+	/// The latter is determined using the system clock in `std` and the block time minus two
+	/// hours in `no-std`.
 	///
 	/// Note that this may cause reentrancy through [`chain::Watch::update_channel`] calls or feerate
 	/// estimate fetches.
@@ -5019,7 +5027,18 @@ where
  self.finish_close_channel(shutdown_res);
  }
 
- self.pending_outbound_payments.remove_stale_payments(&self.pending_events);
+ #[cfg(feature = "std")]
+ let duration_since_epoch = std::time::SystemTime::now()
+ .duration_since(std::time::SystemTime::UNIX_EPOCH)
+ .expect("SystemTime::now() should come after SystemTime::UNIX_EPOCH");
+ #[cfg(not(feature = "std"))]
+ let duration_since_epoch = Duration::from_secs(
+ self.highest_seen_timestamp.load(Ordering::Acquire).saturating_sub(7200) as u64
+ );
+
+ self.pending_outbound_payments.remove_stale_payments(
+ duration_since_epoch, &self.pending_events
+ );
 
  // Technically we don't need to do this here, but if we have holding cell entries in a
  // channel that need freeing, it's better to do that here and block a background task
@@ -7108,6 +7127,71 @@ where
  }
 	}
 
+	/// Creates an [`OfferBuilder`] such that the [`Offer`] it builds is recognized by the
+	/// [`ChannelManager`] when handling [`InvoiceRequest`] messages for the offer. The offer will
+	/// not have an expiration unless otherwise set on the builder.
+	///
+	/// Uses a one-hop [`BlindedPath`] for the offer with [`ChannelManager::get_our_node_id`] as the
+	/// introduction node and a derived signing pubkey for recipient privacy. As such, currently,
+	/// the node must be announced. Otherwise, there is no way to find a path to the introduction
+	/// node in order to send the [`InvoiceRequest`].
+	///
+	/// [`Offer`]: crate::offers::offer::Offer
+	/// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
+	pub fn create_offer_builder(
+ &self, description: String
+	) -> OfferBuilder<DerivedMetadata, secp256k1::All> {
+ let node_id = self.get_our_node_id();
+ let expanded_key = &self.inbound_payment_key;
+ let entropy = &*self.entropy_source;
+ let secp_ctx = &self.secp_ctx;
+ let path = self.create_one_hop_blinded_path();
+
+ OfferBuilder::deriving_signing_pubkey(description, node_id, expanded_key, entropy, secp_ctx)
+ .chain_hash(self.chain_hash)
+ .path(path)
+	}
+
+	/// Creates a [`RefundBuilder`] such that the [`Refund`] it builds is recognized by the
+	/// [`ChannelManager`] when handling [`Bolt12Invoice`] messages for the refund. The builder will
+	/// have the provided expiration set. Any changes to the expiration on the returned builder will
+	/// not be honored by [`ChannelManager`].
+	///
+	/// The provided `payment_id` is used to ensure that only one invoice is paid for the refund.
+	///
+	/// Uses a one-hop [`BlindedPath`] for the refund with [`ChannelManager::get_our_node_id`] as
+	/// the introduction node and a derived payer id for sender privacy. As such, currently, the
+	/// node must be announced. Otherwise, there is no way to find a path to the introduction node
+	/// in order to send the [`Bolt12Invoice`].
+	///
+	/// [`Refund`]: crate::offers::refund::Refund
+	/// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
+	pub fn create_refund_builder(
+ &self, description: String, amount_msats: u64, absolute_expiry: Duration,
+ payment_id: PaymentId, retry_strategy: Retry, max_total_routing_fee_msat: Option<u64>
+	) -> Result<RefundBuilder<secp256k1::All>, Bolt12SemanticError> {
+ let node_id = self.get_our_node_id();
+ let expanded_key = &self.inbound_payment_key;
+ let entropy = &*self.entropy_source;
+ let secp_ctx = &self.secp_ctx;
+ let path = self.create_one_hop_blinded_path();
+
+ let builder = RefundBuilder::deriving_payer_id(
+ description, node_id, expanded_key, entropy, secp_ctx, amount_msats, payment_id
+ )?
+ .chain_hash(self.chain_hash)
+ .absolute_expiry(absolute_expiry)
+ .path(path);
+
+ self.pending_outbound_payments
+ .add_new_awaiting_invoice(
+ payment_id, absolute_expiry, retry_strategy, max_total_routing_fee_msat,
+ )
+ .map_err(|_| Bolt12SemanticError::DuplicatePaymentId)?;
+
+ Ok(builder)
+	}
+
 	/// Gets a payment secret and payment hash for use in an invoice given to a third party wishing
 	/// to pay us.
 	///
@@ -7208,6 +7292,14 @@ where
  inbound_payment::get_payment_preimage(payment_hash, payment_secret, &self.inbound_payment_key)
 	}
 
+	/// Creates a one-hop blinded path with [`ChannelManager::get_our_node_id`] as the introduction
+	/// node.
+	fn create_one_hop_blinded_path(&self) -> BlindedPath {
+ let entropy_source = self.entropy_source.deref();
+ let secp_ctx = &self.secp_ctx;
+ BlindedPath::one_hop_for_message(self.get_our_node_id(), entropy_source, secp_ctx).unwrap()
+	}
+
 	/// Gets a fake short channel id for use in receiving [phantom node payments]. These fake scids
 	/// are used when constructing the phantom invoice's route hints.
 	///

lightning/src/ln/msgs.rs

@@ -49,7 +49,7 @@ use core::str::FromStr;
 use crate::io::{self, Cursor, Read};
 use crate::io_extras::read_to_end;
 
-use crate::events::{MessageSendEventsProvider, OnionMessageProvider};
+use crate::events::MessageSendEventsProvider;
 use crate::util::chacha20poly1305rfc::ChaChaPolyReadAdapter;
 use crate::util::logger;
 use crate::util::ser::{LengthReadable, LengthReadableArgs, Readable, ReadableArgs, Writeable, Writer, WithoutLength, FixedLengthReader, HighZeroBytesDroppedBigSize, Hostname, TransactionU16LenLimited, BigSize};
@@ -1497,17 +1497,22 @@ pub trait RoutingMessageHandler : MessageSendEventsProvider {
 	fn provided_init_features(&self, their_node_id: &PublicKey) -> InitFeatures;
 }
 
-/// A trait to describe an object that can receive onion messages.
-pub trait OnionMessageHandler : OnionMessageProvider {
+/// A handler for received [`OnionMessage`]s and for providing generated ones to send.
+pub trait OnionMessageHandler {
 	/// Handle an incoming `onion_message` message from the given peer.
 	fn handle_onion_message(&self, peer_node_id: &PublicKey, msg: &OnionMessage);
+
+	/// Returns the next pending onion message for the peer with the given node id.
+	fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<OnionMessage>;
+
 	/// Called when a connection is established with a peer. Can be used to track which peers
 	/// advertise onion message support and are online.
 	///
 	/// May return an `Err(())` if the features the peer supports are not sufficient to communicate
 	/// with us. Implementors should be somewhat conservative about doing so, however, as other
 	/// message handlers may still wish to communicate with this peer.
 	fn peer_connected(&self, their_node_id: &PublicKey, init: &Init, inbound: bool) -> Result<(), ()>;
+
 	/// Indicates a connection to the peer failed/an existing connection was lost. Allows handlers to
 	/// drop and refuse to forward onion messages to this peer.
 	fn peer_disconnected(&self, their_node_id: &PublicKey);

fuzz/src/onion_message.rs

@@ -14,7 +14,7 @@ use lightning::offers::invoice_request::UnsignedInvoiceRequest;
 use lightning::util::test_channel_signer::TestChannelSigner;
 use lightning::util::logger::Logger;
 use lightning::util::ser::{Readable, Writeable, Writer};
-use lightning::onion_message::{CustomOnionMessageContents, CustomOnionMessageHandler, Destination, MessageRouter, OffersMessage, OffersMessageHandler, OnionMessagePath, OnionMessenger};
+use lightning::onion_message::{CustomOnionMessageHandler, Destination, MessageRouter, OffersMessage, OffersMessageHandler, OnionMessageContents, OnionMessagePath, OnionMessenger, PendingOnionMessage};
 
 use crate::utils::test_logger;
 
@@ -84,7 +84,7 @@ struct TestCustomMessage {}
 const CUSTOM_MESSAGE_TYPE: u64 = 4242;
 const CUSTOM_MESSAGE_CONTENTS: [u8; 32] = [42; 32];
 
-impl CustomOnionMessageContents for TestCustomMessage {
+impl OnionMessageContents for TestCustomMessage {
 	fn tlv_type(&self) -> u64 {
  CUSTOM_MESSAGE_TYPE
 	}
@@ -108,6 +108,9 @@ impl CustomOnionMessageHandler for TestCustomMessageHandler {
  buffer.read_to_end(&mut buf)?;
  return Ok(Some(TestCustomMessage {}))
 	}
+	fn release_pending_custom_messages(&self) -> Vec<PendingOnionMessage<Self::CustomMessage>> {
+ vec![]
+	}
 }
 
 pub struct VecWriter(pub Vec<u8>);
@@ -208,19 +211,6 @@ mod tests {
 
 	#[test]
 	fn test_no_onion_message_breakage() {
- let one_hop_om = "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";
- let logger = TrackingLogger { lines: Mutex::new(HashMap::new()) };
- super::do_test(&::hex::decode(one_hop_om).unwrap(), &logger);
- {
- let log_entries = logger.lines.lock().unwrap();
- assert_eq!(log_entries.get(&("lightning::onion_message::messenger".to_string(),
- "Received an onion message with path_id None and a reply_path".to_string())), Some(&1));
- assert_eq!(log_entries.get(&("lightning::onion_message::messenger".to_string(),
- "Responding to onion message with path_id None".to_string())), Some(&1));
- assert_eq!(log_entries.get(&("lightning::onion_message::messenger".to_string(),
- "Failed responding to onion message with path_id None: TooFewBlindedHops".to_string())), Some(&1));
- }
-
  let two_unblinded_hops_om = "020000000000000000000000000000000000000000000000000000000000000e01055600020000000000000000000000000000000000000000000000000000000000000e0135043304210202020202020202020202020202020202020202020202020202020202020202026d000000000000000000000000000000eb0000000000000000000000000000000000000000000000000000000000000036041096000000000000000000000000000000fd1092202a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000004800000000000000000000000000000000000000000000000000000000000000";
  let logger = TrackingLogger { lines: Mutex::new(HashMap::new()) };
  super::do_test(&::hex::decode(two_unblinded_hops_om).unwrap(), &logger);

lightning/src/blinded_path/mod.rs

@@ -56,15 +56,22 @@ pub struct BlindedHop {
 }
 
 impl BlindedPath {
+	/// Create a one-hop blinded path for a message.
+	pub fn one_hop_for_message<ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification>(
+ recipient_node_id: PublicKey, entropy_source: &ES, secp_ctx: &Secp256k1<T>
+	) -> Result<Self, ()> {
+ Self::new_for_message(&[recipient_node_id], entropy_source, secp_ctx)
+	}
+
 	/// Create a blinded path for an onion message, to be forwarded along `node_pks`. The last node
 	/// pubkey in `node_pks` will be the destination node.
 	///
-	/// Errors if less than two hops are provided or if `node_pk`(s) are invalid.
+	/// Errors if no hops are provided or if `node_pk`(s) are invalid.
 	// TODO: make all payloads the same size with padding + add dummy hops
-	pub fn new_for_message<ES: EntropySource, T: secp256k1::Signing + secp256k1::Verification>
-(node_pks: &[PublicKey], entropy_source: &ES, secp_ctx: &Secp256k1<T>) -> Result<Self, ()>
-	{
- if node_pks.len() < 2 { return Err(()) }
+	pub fn new_for_message<ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification>(
+ node_pks: &[PublicKey], entropy_source: &ES, secp_ctx: &Secp256k1<T>
+) -> Result<Self, ()> {
+ if node_pks.is_empty() { return Err(()) }
  let blinding_secret_bytes = entropy_source.get_secure_random_bytes();
  let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
  let introduction_node_id = node_pks[0];

lightning/src/events/mod.rs

@@ -1846,12 +1846,6 @@ pub trait MessageSendEventsProvider {
 	fn get_and_clear_pending_msg_events(&self) -> Vec<MessageSendEvent>;
 }
 
-/// A trait indicating an object may generate onion messages to send
-pub trait OnionMessageProvider {
-	/// Gets the next pending onion message for the peer with the given node id.
-	fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<msgs::OnionMessage>;
-}
-
 /// A trait indicating an object may generate events.
 ///
 /// Events are processed by passing an [`EventHandler`] to [`process_pending_events`].

lightning/src/ln/channelmanager.rs

@@ -30,6 +30,7 @@ use bitcoin::secp256k1::{SecretKey,PublicKey};
 use bitcoin::secp256k1::Secp256k1;
 use bitcoin::{LockTime, secp256k1, Sequence};
 
+use crate::blinded_path::BlindedPath;
 use crate::chain;
 use crate::chain::{Confirm, ChannelMonitorUpdateStatus, Watch, BestBlock};
 use crate::chain::chaininterface::{BroadcasterInterface, ConfirmationTarget, FeeEstimator, LowerBoundedFeeEstimator};
@@ -55,6 +56,9 @@ use crate::ln::msgs::{ChannelMessageHandler, DecodeError, LightningError};
 use crate::ln::outbound_payment;
 use crate::ln::outbound_payment::{OutboundPayments, PaymentAttempts, PendingOutboundPayment, SendAlongPathArgs};
 use crate::ln::wire::Encode;
+use crate::offers::offer::{DerivedMetadata, OfferBuilder};
+use crate::offers::parse::Bolt12SemanticError;
+use crate::offers::refund::RefundBuilder;
 use crate::sign::{EntropySource, KeysManager, NodeSigner, Recipient, SignerProvider, WriteableEcdsaChannelSigner};
 use crate::util::config::{UserConfig, ChannelConfig, ChannelConfigUpdate};
 use crate::util::wakers::{Future, Notifier};
@@ -4791,6 +4795,10 @@ where
 	/// with the current [`ChannelConfig`].
 	/// * Removing peers which have disconnected but and no longer have any channels.
 	/// * Force-closing and removing channels which have not completed establishment in a timely manner.
+	/// * Forgetting about stale outbound payments, either those that have already been fulfilled
+	/// or those awaiting an invoice that hasn't been delivered in the necessary amount of time.
+	/// The latter is determined using the system clock in `std` and the block time minus two
+	/// hours in `no-std`.
 	///
 	/// Note that this may cause reentrancy through [`chain::Watch::update_channel`] calls or feerate
 	/// estimate fetches.
@@ -5019,7 +5027,18 @@ where
  self.finish_close_channel(shutdown_res);
  }
 
- self.pending_outbound_payments.remove_stale_payments(&self.pending_events);
+ #[cfg(feature = "std")]
+ let duration_since_epoch = std::time::SystemTime::now()
+ .duration_since(std::time::SystemTime::UNIX_EPOCH)
+ .expect("SystemTime::now() should come after SystemTime::UNIX_EPOCH");
+ #[cfg(not(feature = "std"))]
+ let duration_since_epoch = Duration::from_secs(
+ self.highest_seen_timestamp.load(Ordering::Acquire).saturating_sub(7200) as u64
+ );
+
+ self.pending_outbound_payments.remove_stale_payments(
+ duration_since_epoch, &self.pending_events
+ );
 
  // Technically we don't need to do this here, but if we have holding cell entries in a
  // channel that need freeing, it's better to do that here and block a background task
@@ -7108,6 +7127,71 @@ where
  }
 	}
 
+	/// Creates an [`OfferBuilder`] such that the [`Offer`] it builds is recognized by the
+	/// [`ChannelManager`] when handling [`InvoiceRequest`] messages for the offer. The offer will
+	/// not have an expiration unless otherwise set on the builder.
+	///
+	/// Uses a one-hop [`BlindedPath`] for the offer with [`ChannelManager::get_our_node_id`] as the
+	/// introduction node and a derived signing pubkey for recipient privacy. As such, currently,
+	/// the node must be announced. Otherwise, there is no way to find a path to the introduction
+	/// node in order to send the [`InvoiceRequest`].
+	///
+	/// [`Offer`]: crate::offers::offer::Offer
+	/// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
+	pub fn create_offer_builder(
+ &self, description: String
+	) -> OfferBuilder<DerivedMetadata, secp256k1::All> {
+ let node_id = self.get_our_node_id();
+ let expanded_key = &self.inbound_payment_key;
+ let entropy = &*self.entropy_source;
+ let secp_ctx = &self.secp_ctx;
+ let path = self.create_one_hop_blinded_path();
+
+ OfferBuilder::deriving_signing_pubkey(description, node_id, expanded_key, entropy, secp_ctx)
+ .chain_hash(self.chain_hash)
+ .path(path)
+	}
+
+	/// Creates a [`RefundBuilder`] such that the [`Refund`] it builds is recognized by the
+	/// [`ChannelManager`] when handling [`Bolt12Invoice`] messages for the refund. The builder will
+	/// have the provided expiration set. Any changes to the expiration on the returned builder will
+	/// not be honored by [`ChannelManager`].
+	///
+	/// The provided `payment_id` is used to ensure that only one invoice is paid for the refund.
+	///
+	/// Uses a one-hop [`BlindedPath`] for the refund with [`ChannelManager::get_our_node_id`] as
+	/// the introduction node and a derived payer id for sender privacy. As such, currently, the
+	/// node must be announced. Otherwise, there is no way to find a path to the introduction node
+	/// in order to send the [`Bolt12Invoice`].
+	///
+	/// [`Refund`]: crate::offers::refund::Refund
+	/// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
+	pub fn create_refund_builder(
+ &self, description: String, amount_msats: u64, absolute_expiry: Duration,
+ payment_id: PaymentId, retry_strategy: Retry, max_total_routing_fee_msat: Option<u64>
+	) -> Result<RefundBuilder<secp256k1::All>, Bolt12SemanticError> {
+ let node_id = self.get_our_node_id();
+ let expanded_key = &self.inbound_payment_key;
+ let entropy = &*self.entropy_source;
+ let secp_ctx = &self.secp_ctx;
+ let path = self.create_one_hop_blinded_path();
+
+ let builder = RefundBuilder::deriving_payer_id(
+ description, node_id, expanded_key, entropy, secp_ctx, amount_msats, payment_id
+ )?
+ .chain_hash(self.chain_hash)
+ .absolute_expiry(absolute_expiry)
+ .path(path);
+
+ self.pending_outbound_payments
+ .add_new_awaiting_invoice(
+ payment_id, absolute_expiry, retry_strategy, max_total_routing_fee_msat,
+ )
+ .map_err(|_| Bolt12SemanticError::DuplicatePaymentId)?;
+
+ Ok(builder)
+	}
+
 	/// Gets a payment secret and payment hash for use in an invoice given to a third party wishing
 	/// to pay us.
 	///
@@ -7208,6 +7292,14 @@ where
  inbound_payment::get_payment_preimage(payment_hash, payment_secret, &self.inbound_payment_key)
 	}
 
+	/// Creates a one-hop blinded path with [`ChannelManager::get_our_node_id`] as the introduction
+	/// node.
+	fn create_one_hop_blinded_path(&self) -> BlindedPath {
+ let entropy_source = self.entropy_source.deref();
+ let secp_ctx = &self.secp_ctx;
+ BlindedPath::one_hop_for_message(self.get_our_node_id(), entropy_source, secp_ctx).unwrap()
+	}
+
 	/// Gets a fake short channel id for use in receiving [phantom node payments]. These fake scids
 	/// are used when constructing the phantom invoice's route hints.
 	///

lightning/src/ln/msgs.rs

@@ -49,7 +49,7 @@ use core::str::FromStr;
 use crate::io::{self, Cursor, Read};
 use crate::io_extras::read_to_end;
 
-use crate::events::{MessageSendEventsProvider, OnionMessageProvider};
+use crate::events::MessageSendEventsProvider;
 use crate::util::chacha20poly1305rfc::ChaChaPolyReadAdapter;
 use crate::util::logger;
 use crate::util::ser::{LengthReadable, LengthReadableArgs, Readable, ReadableArgs, Writeable, Writer, WithoutLength, FixedLengthReader, HighZeroBytesDroppedBigSize, Hostname, TransactionU16LenLimited, BigSize};
@@ -1497,17 +1497,22 @@ pub trait RoutingMessageHandler : MessageSendEventsProvider {
 	fn provided_init_features(&self, their_node_id: &PublicKey) -> InitFeatures;
 }
 
-/// A trait to describe an object that can receive onion messages.
-pub trait OnionMessageHandler : OnionMessageProvider {
+/// A handler for received [`OnionMessage`]s and for providing generated ones to send.
+pub trait OnionMessageHandler {
 	/// Handle an incoming `onion_message` message from the given peer.
 	fn handle_onion_message(&self, peer_node_id: &PublicKey, msg: &OnionMessage);
+
+	/// Returns the next pending onion message for the peer with the given node id.
+	fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<OnionMessage>;
+
 	/// Called when a connection is established with a peer. Can be used to track which peers
 	/// advertise onion message support and are online.
 	///
 	/// May return an `Err(())` if the features the peer supports are not sufficient to communicate
 	/// with us. Implementors should be somewhat conservative about doing so, however, as other
 	/// message handlers may still wish to communicate with this peer.
 	fn peer_connected(&self, their_node_id: &PublicKey, init: &Init, inbound: bool) -> Result<(), ()>;
+
 	/// Indicates a connection to the peer failed/an existing connection was lost. Allows handlers to
 	/// drop and refuse to forward onion messages to this peer.
 	fn peer_disconnected(&self, their_node_id: &PublicKey);

fuzz/src/onion_message.rs

@@ -14,7 +14,7 @@ use lightning::offers::invoice_request::UnsignedInvoiceRequest;
 use lightning::util::test_channel_signer::TestChannelSigner;
 use lightning::util::logger::Logger;
 use lightning::util::ser::{Readable, Writeable, Writer};
-use lightning::onion_message::{CustomOnionMessageContents, CustomOnionMessageHandler, Destination, MessageRouter, OffersMessage, OffersMessageHandler, OnionMessagePath, OnionMessenger};
+use lightning::onion_message::{CustomOnionMessageHandler, Destination, MessageRouter, OffersMessage, OffersMessageHandler, OnionMessageContents, OnionMessagePath, OnionMessenger, PendingOnionMessage};
 
 use crate::utils::test_logger;
 
@@ -84,7 +84,7 @@ struct TestCustomMessage {}
 const CUSTOM_MESSAGE_TYPE: u64 = 4242;
 const CUSTOM_MESSAGE_CONTENTS: [u8; 32] = [42; 32];
 
-impl CustomOnionMessageContents for TestCustomMessage {
+impl OnionMessageContents for TestCustomMessage {
 	fn tlv_type(&self) -> u64 {
  CUSTOM_MESSAGE_TYPE
 	}
@@ -108,6 +108,9 @@ impl CustomOnionMessageHandler for TestCustomMessageHandler {
  buffer.read_to_end(&mut buf)?;
  return Ok(Some(TestCustomMessage {}))
 	}
+	fn release_pending_custom_messages(&self) -> Vec<PendingOnionMessage<Self::CustomMessage>> {
+ vec![]
+	}
 }
 
 pub struct VecWriter(pub Vec<u8>);
@@ -208,19 +211,6 @@ mod tests {
 
 	#[test]
 	fn test_no_onion_message_breakage() {
- let one_hop_om = "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";
- let logger = TrackingLogger { lines: Mutex::new(HashMap::new()) };
- super::do_test(&::hex::decode(one_hop_om).unwrap(), &logger);
- {
- let log_entries = logger.lines.lock().unwrap();
- assert_eq!(log_entries.get(&("lightning::onion_message::messenger".to_string(),
- "Received an onion message with path_id None and a reply_path".to_string())), Some(&1));
- assert_eq!(log_entries.get(&("lightning::onion_message::messenger".to_string(),
- "Responding to onion message with path_id None".to_string())), Some(&1));
- assert_eq!(log_entries.get(&("lightning::onion_message::messenger".to_string(),
- "Failed responding to onion message with path_id None: TooFewBlindedHops".to_string())), Some(&1));
- }
-
  let two_unblinded_hops_om = "020000000000000000000000000000000000000000000000000000000000000e01055600020000000000000000000000000000000000000000000000000000000000000e0135043304210202020202020202020202020202020202020202020202020202020202020202026d000000000000000000000000000000eb0000000000000000000000000000000000000000000000000000000000000036041096000000000000000000000000000000fd1092202a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000004800000000000000000000000000000000000000000000000000000000000000";
  let logger = TrackingLogger { lines: Mutex::new(HashMap::new()) };
  super::do_test(&::hex::decode(two_unblinded_hops_om).unwrap(), &logger);

lightning/src/blinded_path/mod.rs

@@ -56,15 +56,22 @@ pub struct BlindedHop {
 }
 
 impl BlindedPath {
+	/// Create a one-hop blinded path for a message.
+	pub fn one_hop_for_message<ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification>(
+ recipient_node_id: PublicKey, entropy_source: &ES, secp_ctx: &Secp256k1<T>
+	) -> Result<Self, ()> {
+ Self::new_for_message(&[recipient_node_id], entropy_source, secp_ctx)
+	}
+
 	/// Create a blinded path for an onion message, to be forwarded along `node_pks`. The last node
 	/// pubkey in `node_pks` will be the destination node.
 	///
-	/// Errors if less than two hops are provided or if `node_pk`(s) are invalid.
+	/// Errors if no hops are provided or if `node_pk`(s) are invalid.
 	// TODO: make all payloads the same size with padding + add dummy hops
-	pub fn new_for_message<ES: EntropySource, T: secp256k1::Signing + secp256k1::Verification>
-(node_pks: &[PublicKey], entropy_source: &ES, secp_ctx: &Secp256k1<T>) -> Result<Self, ()>
-	{
- if node_pks.len() < 2 { return Err(()) }
+	pub fn new_for_message<ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification>(
+ node_pks: &[PublicKey], entropy_source: &ES, secp_ctx: &Secp256k1<T>
+) -> Result<Self, ()> {
+ if node_pks.is_empty() { return Err(()) }
  let blinding_secret_bytes = entropy_source.get_secure_random_bytes();
  let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
  let introduction_node_id = node_pks[0];

lightning/src/events/mod.rs

@@ -1846,12 +1846,6 @@ pub trait MessageSendEventsProvider {
 	fn get_and_clear_pending_msg_events(&self) -> Vec<MessageSendEvent>;
 }
 
-/// A trait indicating an object may generate onion messages to send
-pub trait OnionMessageProvider {
-	/// Gets the next pending onion message for the peer with the given node id.
-	fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<msgs::OnionMessage>;
-}
-
 /// A trait indicating an object may generate events.
 ///
 /// Events are processed by passing an [`EventHandler`] to [`process_pending_events`].

lightning/src/ln/channelmanager.rs

@@ -30,6 +30,7 @@ use bitcoin::secp256k1::{SecretKey,PublicKey};
 use bitcoin::secp256k1::Secp256k1;
 use bitcoin::{LockTime, secp256k1, Sequence};
 
+use crate::blinded_path::BlindedPath;
 use crate::chain;
 use crate::chain::{Confirm, ChannelMonitorUpdateStatus, Watch, BestBlock};
 use crate::chain::chaininterface::{BroadcasterInterface, ConfirmationTarget, FeeEstimator, LowerBoundedFeeEstimator};
@@ -55,6 +56,9 @@ use crate::ln::msgs::{ChannelMessageHandler, DecodeError, LightningError};
 use crate::ln::outbound_payment;
 use crate::ln::outbound_payment::{OutboundPayments, PaymentAttempts, PendingOutboundPayment, SendAlongPathArgs};
 use crate::ln::wire::Encode;
+use crate::offers::offer::{DerivedMetadata, OfferBuilder};
+use crate::offers::parse::Bolt12SemanticError;
+use crate::offers::refund::RefundBuilder;
 use crate::sign::{EntropySource, KeysManager, NodeSigner, Recipient, SignerProvider, WriteableEcdsaChannelSigner};
 use crate::util::config::{UserConfig, ChannelConfig, ChannelConfigUpdate};
 use crate::util::wakers::{Future, Notifier};
@@ -4791,6 +4795,10 @@ where
 	/// with the current [`ChannelConfig`].
 	/// * Removing peers which have disconnected but and no longer have any channels.
 	/// * Force-closing and removing channels which have not completed establishment in a timely manner.
+	/// * Forgetting about stale outbound payments, either those that have already been fulfilled
+	/// or those awaiting an invoice that hasn't been delivered in the necessary amount of time.
+	/// The latter is determined using the system clock in `std` and the block time minus two
+	/// hours in `no-std`.
 	///
 	/// Note that this may cause reentrancy through [`chain::Watch::update_channel`] calls or feerate
 	/// estimate fetches.
@@ -5019,7 +5027,18 @@ where
  self.finish_close_channel(shutdown_res);
  }
 
- self.pending_outbound_payments.remove_stale_payments(&self.pending_events);
+ #[cfg(feature = "std")]
+ let duration_since_epoch = std::time::SystemTime::now()
+ .duration_since(std::time::SystemTime::UNIX_EPOCH)
+ .expect("SystemTime::now() should come after SystemTime::UNIX_EPOCH");
+ #[cfg(not(feature = "std"))]
+ let duration_since_epoch = Duration::from_secs(
+ self.highest_seen_timestamp.load(Ordering::Acquire).saturating_sub(7200) as u64
+ );
+
+ self.pending_outbound_payments.remove_stale_payments(
+ duration_since_epoch, &self.pending_events
+ );
 
  // Technically we don't need to do this here, but if we have holding cell entries in a
  // channel that need freeing, it's better to do that here and block a background task
@@ -7108,6 +7127,71 @@ where
  }
 	}
 
+	/// Creates an [`OfferBuilder`] such that the [`Offer`] it builds is recognized by the
+	/// [`ChannelManager`] when handling [`InvoiceRequest`] messages for the offer. The offer will
+	/// not have an expiration unless otherwise set on the builder.
+	///
+	/// Uses a one-hop [`BlindedPath`] for the offer with [`ChannelManager::get_our_node_id`] as the
+	/// introduction node and a derived signing pubkey for recipient privacy. As such, currently,
+	/// the node must be announced. Otherwise, there is no way to find a path to the introduction
+	/// node in order to send the [`InvoiceRequest`].
+	///
+	/// [`Offer`]: crate::offers::offer::Offer
+	/// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
+	pub fn create_offer_builder(
+ &self, description: String
+	) -> OfferBuilder<DerivedMetadata, secp256k1::All> {
+ let node_id = self.get_our_node_id();
+ let expanded_key = &self.inbound_payment_key;
+ let entropy = &*self.entropy_source;
+ let secp_ctx = &self.secp_ctx;
+ let path = self.create_one_hop_blinded_path();
+
+ OfferBuilder::deriving_signing_pubkey(description, node_id, expanded_key, entropy, secp_ctx)
+ .chain_hash(self.chain_hash)
+ .path(path)
+	}
+
+	/// Creates a [`RefundBuilder`] such that the [`Refund`] it builds is recognized by the
+	/// [`ChannelManager`] when handling [`Bolt12Invoice`] messages for the refund. The builder will
+	/// have the provided expiration set. Any changes to the expiration on the returned builder will
+	/// not be honored by [`ChannelManager`].
+	///
+	/// The provided `payment_id` is used to ensure that only one invoice is paid for the refund.
+	///
+	/// Uses a one-hop [`BlindedPath`] for the refund with [`ChannelManager::get_our_node_id`] as
+	/// the introduction node and a derived payer id for sender privacy. As such, currently, the
+	/// node must be announced. Otherwise, there is no way to find a path to the introduction node
+	/// in order to send the [`Bolt12Invoice`].
+	///
+	/// [`Refund`]: crate::offers::refund::Refund
+	/// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
+	pub fn create_refund_builder(
+ &self, description: String, amount_msats: u64, absolute_expiry: Duration,
+ payment_id: PaymentId, retry_strategy: Retry, max_total_routing_fee_msat: Option<u64>
+	) -> Result<RefundBuilder<secp256k1::All>, Bolt12SemanticError> {
+ let node_id = self.get_our_node_id();
+ let expanded_key = &self.inbound_payment_key;
+ let entropy = &*self.entropy_source;
+ let secp_ctx = &self.secp_ctx;
+ let path = self.create_one_hop_blinded_path();
+
+ let builder = RefundBuilder::deriving_payer_id(
+ description, node_id, expanded_key, entropy, secp_ctx, amount_msats, payment_id
+ )?
+ .chain_hash(self.chain_hash)
+ .absolute_expiry(absolute_expiry)
+ .path(path);
+
+ self.pending_outbound_payments
+ .add_new_awaiting_invoice(
+ payment_id, absolute_expiry, retry_strategy, max_total_routing_fee_msat,
+ )
+ .map_err(|_| Bolt12SemanticError::DuplicatePaymentId)?;
+
+ Ok(builder)
+	}
+
 	/// Gets a payment secret and payment hash for use in an invoice given to a third party wishing
 	/// to pay us.
 	///
@@ -7208,6 +7292,14 @@ where
  inbound_payment::get_payment_preimage(payment_hash, payment_secret, &self.inbound_payment_key)
 	}
 
+	/// Creates a one-hop blinded path with [`ChannelManager::get_our_node_id`] as the introduction
+	/// node.
+	fn create_one_hop_blinded_path(&self) -> BlindedPath {
+ let entropy_source = self.entropy_source.deref();
+ let secp_ctx = &self.secp_ctx;
+ BlindedPath::one_hop_for_message(self.get_our_node_id(), entropy_source, secp_ctx).unwrap()
+	}
+
 	/// Gets a fake short channel id for use in receiving [phantom node payments]. These fake scids
 	/// are used when constructing the phantom invoice's route hints.
 	///

lightning/src/ln/msgs.rs

@@ -49,7 +49,7 @@ use core::str::FromStr;
 use crate::io::{self, Cursor, Read};
 use crate::io_extras::read_to_end;
 
-use crate::events::{MessageSendEventsProvider, OnionMessageProvider};
+use crate::events::MessageSendEventsProvider;
 use crate::util::chacha20poly1305rfc::ChaChaPolyReadAdapter;
 use crate::util::logger;
 use crate::util::ser::{LengthReadable, LengthReadableArgs, Readable, ReadableArgs, Writeable, Writer, WithoutLength, FixedLengthReader, HighZeroBytesDroppedBigSize, Hostname, TransactionU16LenLimited, BigSize};
@@ -1497,17 +1497,22 @@ pub trait RoutingMessageHandler : MessageSendEventsProvider {
 	fn provided_init_features(&self, their_node_id: &PublicKey) -> InitFeatures;
 }
 
-/// A trait to describe an object that can receive onion messages.
-pub trait OnionMessageHandler : OnionMessageProvider {
+/// A handler for received [`OnionMessage`]s and for providing generated ones to send.
+pub trait OnionMessageHandler {
 	/// Handle an incoming `onion_message` message from the given peer.
 	fn handle_onion_message(&self, peer_node_id: &PublicKey, msg: &OnionMessage);
+
+	/// Returns the next pending onion message for the peer with the given node id.
+	fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<OnionMessage>;
+
 	/// Called when a connection is established with a peer. Can be used to track which peers
 	/// advertise onion message support and are online.
 	///
 	/// May return an `Err(())` if the features the peer supports are not sufficient to communicate
 	/// with us. Implementors should be somewhat conservative about doing so, however, as other
 	/// message handlers may still wish to communicate with this peer.
 	fn peer_connected(&self, their_node_id: &PublicKey, init: &Init, inbound: bool) -> Result<(), ()>;
+
 	/// Indicates a connection to the peer failed/an existing connection was lost. Allows handlers to
 	/// drop and refuse to forward onion messages to this peer.
 	fn peer_disconnected(&self, their_node_id: &PublicKey);

fuzz/src/onion_message.rs

@@ -14,7 +14,7 @@ use lightning::offers::invoice_request::UnsignedInvoiceRequest;
 use lightning::util::test_channel_signer::TestChannelSigner;
 use lightning::util::logger::Logger;
 use lightning::util::ser::{Readable, Writeable, Writer};
-use lightning::onion_message::{CustomOnionMessageContents, CustomOnionMessageHandler, Destination, MessageRouter, OffersMessage, OffersMessageHandler, OnionMessagePath, OnionMessenger};
+use lightning::onion_message::{CustomOnionMessageHandler, Destination, MessageRouter, OffersMessage, OffersMessageHandler, OnionMessageContents, OnionMessagePath, OnionMessenger, PendingOnionMessage};
 
 use crate::utils::test_logger;
 
@@ -84,7 +84,7 @@ struct TestCustomMessage {}
 const CUSTOM_MESSAGE_TYPE: u64 = 4242;
 const CUSTOM_MESSAGE_CONTENTS: [u8; 32] = [42; 32];
 
-impl CustomOnionMessageContents for TestCustomMessage {
+impl OnionMessageContents for TestCustomMessage {
 	fn tlv_type(&self) -> u64 {
  CUSTOM_MESSAGE_TYPE
 	}
@@ -108,6 +108,9 @@ impl CustomOnionMessageHandler for TestCustomMessageHandler {
  buffer.read_to_end(&mut buf)?;
  return Ok(Some(TestCustomMessage {}))
 	}
+	fn release_pending_custom_messages(&self) -> Vec<PendingOnionMessage<Self::CustomMessage>> {
+ vec![]
+	}
 }
 
 pub struct VecWriter(pub Vec<u8>);
@@ -208,19 +211,6 @@ mod tests {
 
 	#[test]
 	fn test_no_onion_message_breakage() {
- let one_hop_om = "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";
- let logger = TrackingLogger { lines: Mutex::new(HashMap::new()) };
- super::do_test(&::hex::decode(one_hop_om).unwrap(), &logger);
- {
- let log_entries = logger.lines.lock().unwrap();
- assert_eq!(log_entries.get(&("lightning::onion_message::messenger".to_string(),
- "Received an onion message with path_id None and a reply_path".to_string())), Some(&1));
- assert_eq!(log_entries.get(&("lightning::onion_message::messenger".to_string(),
- "Responding to onion message with path_id None".to_string())), Some(&1));
- assert_eq!(log_entries.get(&("lightning::onion_message::messenger".to_string(),
- "Failed responding to onion message with path_id None: TooFewBlindedHops".to_string())), Some(&1));
- }
-
  let two_unblinded_hops_om = "020000000000000000000000000000000000000000000000000000000000000e01055600020000000000000000000000000000000000000000000000000000000000000e0135043304210202020202020202020202020202020202020202020202020202020202020202026d000000000000000000000000000000eb0000000000000000000000000000000000000000000000000000000000000036041096000000000000000000000000000000fd1092202a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000004800000000000000000000000000000000000000000000000000000000000000";
  let logger = TrackingLogger { lines: Mutex::new(HashMap::new()) };
  super::do_test(&::hex::decode(two_unblinded_hops_om).unwrap(), &logger);

lightning/src/blinded_path/mod.rs

@@ -56,15 +56,22 @@ pub struct BlindedHop {
 }
 
 impl BlindedPath {
+	/// Create a one-hop blinded path for a message.
+	pub fn one_hop_for_message<ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification>(
+ recipient_node_id: PublicKey, entropy_source: &ES, secp_ctx: &Secp256k1<T>
+	) -> Result<Self, ()> {
+ Self::new_for_message(&[recipient_node_id], entropy_source, secp_ctx)
+	}
+
 	/// Create a blinded path for an onion message, to be forwarded along `node_pks`. The last node
 	/// pubkey in `node_pks` will be the destination node.
 	///
-	/// Errors if less than two hops are provided or if `node_pk`(s) are invalid.
+	/// Errors if no hops are provided or if `node_pk`(s) are invalid.
 	// TODO: make all payloads the same size with padding + add dummy hops
-	pub fn new_for_message<ES: EntropySource, T: secp256k1::Signing + secp256k1::Verification>
-(node_pks: &[PublicKey], entropy_source: &ES, secp_ctx: &Secp256k1<T>) -> Result<Self, ()>
-	{
- if node_pks.len() < 2 { return Err(()) }
+	pub fn new_for_message<ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification>(
+ node_pks: &[PublicKey], entropy_source: &ES, secp_ctx: &Secp256k1<T>
+) -> Result<Self, ()> {
+ if node_pks.is_empty() { return Err(()) }
  let blinding_secret_bytes = entropy_source.get_secure_random_bytes();
  let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
  let introduction_node_id = node_pks[0];

lightning/src/events/mod.rs

@@ -1846,12 +1846,6 @@ pub trait MessageSendEventsProvider {
 	fn get_and_clear_pending_msg_events(&self) -> Vec<MessageSendEvent>;
 }
 
-/// A trait indicating an object may generate onion messages to send
-pub trait OnionMessageProvider {
-	/// Gets the next pending onion message for the peer with the given node id.
-	fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<msgs::OnionMessage>;
-}
-
 /// A trait indicating an object may generate events.
 ///
 /// Events are processed by passing an [`EventHandler`] to [`process_pending_events`].

lightning/src/ln/channelmanager.rs

@@ -30,6 +30,7 @@ use bitcoin::secp256k1::{SecretKey,PublicKey};
 use bitcoin::secp256k1::Secp256k1;
 use bitcoin::{LockTime, secp256k1, Sequence};
 
+use crate::blinded_path::BlindedPath;
 use crate::chain;
 use crate::chain::{Confirm, ChannelMonitorUpdateStatus, Watch, BestBlock};
 use crate::chain::chaininterface::{BroadcasterInterface, ConfirmationTarget, FeeEstimator, LowerBoundedFeeEstimator};
@@ -55,6 +56,9 @@ use crate::ln::msgs::{ChannelMessageHandler, DecodeError, LightningError};
 use crate::ln::outbound_payment;
 use crate::ln::outbound_payment::{OutboundPayments, PaymentAttempts, PendingOutboundPayment, SendAlongPathArgs};
 use crate::ln::wire::Encode;
+use crate::offers::offer::{DerivedMetadata, OfferBuilder};
+use crate::offers::parse::Bolt12SemanticError;
+use crate::offers::refund::RefundBuilder;
 use crate::sign::{EntropySource, KeysManager, NodeSigner, Recipient, SignerProvider, WriteableEcdsaChannelSigner};
 use crate::util::config::{UserConfig, ChannelConfig, ChannelConfigUpdate};
 use crate::util::wakers::{Future, Notifier};
@@ -4791,6 +4795,10 @@ where
 	/// with the current [`ChannelConfig`].
 	/// * Removing peers which have disconnected but and no longer have any channels.
 	/// * Force-closing and removing channels which have not completed establishment in a timely manner.
+	/// * Forgetting about stale outbound payments, either those that have already been fulfilled
+	/// or those awaiting an invoice that hasn't been delivered in the necessary amount of time.
+	/// The latter is determined using the system clock in `std` and the block time minus two
+	/// hours in `no-std`.
 	///
 	/// Note that this may cause reentrancy through [`chain::Watch::update_channel`] calls or feerate
 	/// estimate fetches.
@@ -5019,7 +5027,18 @@ where
  self.finish_close_channel(shutdown_res);
  }
 
- self.pending_outbound_payments.remove_stale_payments(&self.pending_events);
+ #[cfg(feature = "std")]
+ let duration_since_epoch = std::time::SystemTime::now()
+ .duration_since(std::time::SystemTime::UNIX_EPOCH)
+ .expect("SystemTime::now() should come after SystemTime::UNIX_EPOCH");
+ #[cfg(not(feature = "std"))]
+ let duration_since_epoch = Duration::from_secs(
+ self.highest_seen_timestamp.load(Ordering::Acquire).saturating_sub(7200) as u64
+ );
+
+ self.pending_outbound_payments.remove_stale_payments(
+ duration_since_epoch, &self.pending_events
+ );
 
  // Technically we don't need to do this here, but if we have holding cell entries in a
  // channel that need freeing, it's better to do that here and block a background task
@@ -7108,6 +7127,71 @@ where
  }
 	}
 
+	/// Creates an [`OfferBuilder`] such that the [`Offer`] it builds is recognized by the
+	/// [`ChannelManager`] when handling [`InvoiceRequest`] messages for the offer. The offer will
+	/// not have an expiration unless otherwise set on the builder.
+	///
+	/// Uses a one-hop [`BlindedPath`] for the offer with [`ChannelManager::get_our_node_id`] as the
+	/// introduction node and a derived signing pubkey for recipient privacy. As such, currently,
+	/// the node must be announced. Otherwise, there is no way to find a path to the introduction
+	/// node in order to send the [`InvoiceRequest`].
+	///
+	/// [`Offer`]: crate::offers::offer::Offer
+	/// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
+	pub fn create_offer_builder(
+ &self, description: String
+	) -> OfferBuilder<DerivedMetadata, secp256k1::All> {
+ let node_id = self.get_our_node_id();
+ let expanded_key = &self.inbound_payment_key;
+ let entropy = &*self.entropy_source;
+ let secp_ctx = &self.secp_ctx;
+ let path = self.create_one_hop_blinded_path();
+
+ OfferBuilder::deriving_signing_pubkey(description, node_id, expanded_key, entropy, secp_ctx)
+ .chain_hash(self.chain_hash)
+ .path(path)
+	}
+
+	/// Creates a [`RefundBuilder`] such that the [`Refund`] it builds is recognized by the
+	/// [`ChannelManager`] when handling [`Bolt12Invoice`] messages for the refund. The builder will
+	/// have the provided expiration set. Any changes to the expiration on the returned builder will
+	/// not be honored by [`ChannelManager`].
+	///
+	/// The provided `payment_id` is used to ensure that only one invoice is paid for the refund.
+	///
+	/// Uses a one-hop [`BlindedPath`] for the refund with [`ChannelManager::get_our_node_id`] as
+	/// the introduction node and a derived payer id for sender privacy. As such, currently, the
+	/// node must be announced. Otherwise, there is no way to find a path to the introduction node
+	/// in order to send the [`Bolt12Invoice`].
+	///
+	/// [`Refund`]: crate::offers::refund::Refund
+	/// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
+	pub fn create_refund_builder(
+ &self, description: String, amount_msats: u64, absolute_expiry: Duration,
+ payment_id: PaymentId, retry_strategy: Retry, max_total_routing_fee_msat: Option<u64>
+	) -> Result<RefundBuilder<secp256k1::All>, Bolt12SemanticError> {
+ let node_id = self.get_our_node_id();
+ let expanded_key = &self.inbound_payment_key;
+ let entropy = &*self.entropy_source;
+ let secp_ctx = &self.secp_ctx;
+ let path = self.create_one_hop_blinded_path();
+
+ let builder = RefundBuilder::deriving_payer_id(
+ description, node_id, expanded_key, entropy, secp_ctx, amount_msats, payment_id
+ )?
+ .chain_hash(self.chain_hash)
+ .absolute_expiry(absolute_expiry)
+ .path(path);
+
+ self.pending_outbound_payments
+ .add_new_awaiting_invoice(
+ payment_id, absolute_expiry, retry_strategy, max_total_routing_fee_msat,
+ )
+ .map_err(|_| Bolt12SemanticError::DuplicatePaymentId)?;
+
+ Ok(builder)
+	}
+
 	/// Gets a payment secret and payment hash for use in an invoice given to a third party wishing
 	/// to pay us.
 	///
@@ -7208,6 +7292,14 @@ where
  inbound_payment::get_payment_preimage(payment_hash, payment_secret, &self.inbound_payment_key)
 	}
 
+	/// Creates a one-hop blinded path with [`ChannelManager::get_our_node_id`] as the introduction
+	/// node.
+	fn create_one_hop_blinded_path(&self) -> BlindedPath {
+ let entropy_source = self.entropy_source.deref();
+ let secp_ctx = &self.secp_ctx;
+ BlindedPath::one_hop_for_message(self.get_our_node_id(), entropy_source, secp_ctx).unwrap()
+	}
+
 	/// Gets a fake short channel id for use in receiving [phantom node payments]. These fake scids
 	/// are used when constructing the phantom invoice's route hints.
 	///

lightning/src/ln/msgs.rs

@@ -49,7 +49,7 @@ use core::str::FromStr;
 use crate::io::{self, Cursor, Read};
 use crate::io_extras::read_to_end;
 
-use crate::events::{MessageSendEventsProvider, OnionMessageProvider};
+use crate::events::MessageSendEventsProvider;
 use crate::util::chacha20poly1305rfc::ChaChaPolyReadAdapter;
 use crate::util::logger;
 use crate::util::ser::{LengthReadable, LengthReadableArgs, Readable, ReadableArgs, Writeable, Writer, WithoutLength, FixedLengthReader, HighZeroBytesDroppedBigSize, Hostname, TransactionU16LenLimited, BigSize};
@@ -1497,17 +1497,22 @@ pub trait RoutingMessageHandler : MessageSendEventsProvider {
 	fn provided_init_features(&self, their_node_id: &PublicKey) -> InitFeatures;
 }
 
-/// A trait to describe an object that can receive onion messages.
-pub trait OnionMessageHandler : OnionMessageProvider {
+/// A handler for received [`OnionMessage`]s and for providing generated ones to send.
+pub trait OnionMessageHandler {
 	/// Handle an incoming `onion_message` message from the given peer.
 	fn handle_onion_message(&self, peer_node_id: &PublicKey, msg: &OnionMessage);
+
+	/// Returns the next pending onion message for the peer with the given node id.
+	fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<OnionMessage>;
+
 	/// Called when a connection is established with a peer. Can be used to track which peers
 	/// advertise onion message support and are online.
 	///
 	/// May return an `Err(())` if the features the peer supports are not sufficient to communicate
 	/// with us. Implementors should be somewhat conservative about doing so, however, as other
 	/// message handlers may still wish to communicate with this peer.
 	fn peer_connected(&self, their_node_id: &PublicKey, init: &Init, inbound: bool) -> Result<(), ()>;
+
 	/// Indicates a connection to the peer failed/an existing connection was lost. Allows handlers to
 	/// drop and refuse to forward onion messages to this peer.
 	fn peer_disconnected(&self, their_node_id: &PublicKey);

fuzz/src/onion_message.rs

@@ -14,7 +14,7 @@ use lightning::offers::invoice_request::UnsignedInvoiceRequest;
 use lightning::util::test_channel_signer::TestChannelSigner;
 use lightning::util::logger::Logger;
 use lightning::util::ser::{Readable, Writeable, Writer};
-use lightning::onion_message::{CustomOnionMessageContents, CustomOnionMessageHandler, Destination, MessageRouter, OffersMessage, OffersMessageHandler, OnionMessagePath, OnionMessenger};
+use lightning::onion_message::{CustomOnionMessageHandler, Destination, MessageRouter, OffersMessage, OffersMessageHandler, OnionMessageContents, OnionMessagePath, OnionMessenger, PendingOnionMessage};
 
 use crate::utils::test_logger;
 
@@ -84,7 +84,7 @@ struct TestCustomMessage {}
 const CUSTOM_MESSAGE_TYPE: u64 = 4242;
 const CUSTOM_MESSAGE_CONTENTS: [u8; 32] = [42; 32];
 
-impl CustomOnionMessageContents for TestCustomMessage {
+impl OnionMessageContents for TestCustomMessage {
 	fn tlv_type(&self) -> u64 {
  CUSTOM_MESSAGE_TYPE
 	}
@@ -108,6 +108,9 @@ impl CustomOnionMessageHandler for TestCustomMessageHandler {
  buffer.read_to_end(&mut buf)?;
  return Ok(Some(TestCustomMessage {}))
 	}
+	fn release_pending_custom_messages(&self) -> Vec<PendingOnionMessage<Self::CustomMessage>> {
+ vec![]
+	}
 }
 
 pub struct VecWriter(pub Vec<u8>);
@@ -208,19 +211,6 @@ mod tests {
 
 	#[test]
 	fn test_no_onion_message_breakage() {
- let one_hop_om = "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";
- let logger = TrackingLogger { lines: Mutex::new(HashMap::new()) };
- super::do_test(&::hex::decode(one_hop_om).unwrap(), &logger);
- {
- let log_entries = logger.lines.lock().unwrap();
- assert_eq!(log_entries.get(&("lightning::onion_message::messenger".to_string(),
- "Received an onion message with path_id None and a reply_path".to_string())), Some(&1));
- assert_eq!(log_entries.get(&("lightning::onion_message::messenger".to_string(),
- "Responding to onion message with path_id None".to_string())), Some(&1));
- assert_eq!(log_entries.get(&("lightning::onion_message::messenger".to_string(),
- "Failed responding to onion message with path_id None: TooFewBlindedHops".to_string())), Some(&1));
- }
-
  let two_unblinded_hops_om = "020000000000000000000000000000000000000000000000000000000000000e01055600020000000000000000000000000000000000000000000000000000000000000e0135043304210202020202020202020202020202020202020202020202020202020202020202026d000000000000000000000000000000eb0000000000000000000000000000000000000000000000000000000000000036041096000000000000000000000000000000fd1092202a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000004800000000000000000000000000000000000000000000000000000000000000";
  let logger = TrackingLogger { lines: Mutex::new(HashMap::new()) };
  super::do_test(&::hex::decode(two_unblinded_hops_om).unwrap(), &logger);

lightning/src/blinded_path/mod.rs

@@ -56,15 +56,22 @@ pub struct BlindedHop {
 }
 
 impl BlindedPath {
+	/// Create a one-hop blinded path for a message.
+	pub fn one_hop_for_message<ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification>(
+ recipient_node_id: PublicKey, entropy_source: &ES, secp_ctx: &Secp256k1<T>
+	) -> Result<Self, ()> {
+ Self::new_for_message(&[recipient_node_id], entropy_source, secp_ctx)
+	}
+
 	/// Create a blinded path for an onion message, to be forwarded along `node_pks`. The last node
 	/// pubkey in `node_pks` will be the destination node.
 	///
-	/// Errors if less than two hops are provided or if `node_pk`(s) are invalid.
+	/// Errors if no hops are provided or if `node_pk`(s) are invalid.
 	// TODO: make all payloads the same size with padding + add dummy hops
-	pub fn new_for_message<ES: EntropySource, T: secp256k1::Signing + secp256k1::Verification>
-(node_pks: &[PublicKey], entropy_source: &ES, secp_ctx: &Secp256k1<T>) -> Result<Self, ()>
-	{
- if node_pks.len() < 2 { return Err(()) }
+	pub fn new_for_message<ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification>(
+ node_pks: &[PublicKey], entropy_source: &ES, secp_ctx: &Secp256k1<T>
+) -> Result<Self, ()> {
+ if node_pks.is_empty() { return Err(()) }
  let blinding_secret_bytes = entropy_source.get_secure_random_bytes();
  let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
  let introduction_node_id = node_pks[0];

lightning/src/events/mod.rs

@@ -1846,12 +1846,6 @@ pub trait MessageSendEventsProvider {
 	fn get_and_clear_pending_msg_events(&self) -> Vec<MessageSendEvent>;
 }
 
-/// A trait indicating an object may generate onion messages to send
-pub trait OnionMessageProvider {
-	/// Gets the next pending onion message for the peer with the given node id.
-	fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<msgs::OnionMessage>;
-}
-
 /// A trait indicating an object may generate events.
 ///
 /// Events are processed by passing an [`EventHandler`] to [`process_pending_events`].

lightning/src/ln/channelmanager.rs

@@ -30,6 +30,7 @@ use bitcoin::secp256k1::{SecretKey,PublicKey};
 use bitcoin::secp256k1::Secp256k1;
 use bitcoin::{LockTime, secp256k1, Sequence};
 
+use crate::blinded_path::BlindedPath;
 use crate::chain;
 use crate::chain::{Confirm, ChannelMonitorUpdateStatus, Watch, BestBlock};
 use crate::chain::chaininterface::{BroadcasterInterface, ConfirmationTarget, FeeEstimator, LowerBoundedFeeEstimator};
@@ -55,6 +56,9 @@ use crate::ln::msgs::{ChannelMessageHandler, DecodeError, LightningError};
 use crate::ln::outbound_payment;
 use crate::ln::outbound_payment::{OutboundPayments, PaymentAttempts, PendingOutboundPayment, SendAlongPathArgs};
 use crate::ln::wire::Encode;
+use crate::offers::offer::{DerivedMetadata, OfferBuilder};
+use crate::offers::parse::Bolt12SemanticError;
+use crate::offers::refund::RefundBuilder;
 use crate::sign::{EntropySource, KeysManager, NodeSigner, Recipient, SignerProvider, WriteableEcdsaChannelSigner};
 use crate::util::config::{UserConfig, ChannelConfig, ChannelConfigUpdate};
 use crate::util::wakers::{Future, Notifier};
@@ -4791,6 +4795,10 @@ where
 	/// with the current [`ChannelConfig`].
 	/// * Removing peers which have disconnected but and no longer have any channels.
 	/// * Force-closing and removing channels which have not completed establishment in a timely manner.
+	/// * Forgetting about stale outbound payments, either those that have already been fulfilled
+	/// or those awaiting an invoice that hasn't been delivered in the necessary amount of time.
+	/// The latter is determined using the system clock in `std` and the block time minus two
+	/// hours in `no-std`.
 	///
 	/// Note that this may cause reentrancy through [`chain::Watch::update_channel`] calls or feerate
 	/// estimate fetches.
@@ -5019,7 +5027,18 @@ where
  self.finish_close_channel(shutdown_res);
  }
 
- self.pending_outbound_payments.remove_stale_payments(&self.pending_events);
+ #[cfg(feature = "std")]
+ let duration_since_epoch = std::time::SystemTime::now()
+ .duration_since(std::time::SystemTime::UNIX_EPOCH)
+ .expect("SystemTime::now() should come after SystemTime::UNIX_EPOCH");
+ #[cfg(not(feature = "std"))]
+ let duration_since_epoch = Duration::from_secs(
+ self.highest_seen_timestamp.load(Ordering::Acquire).saturating_sub(7200) as u64
+ );
+
+ self.pending_outbound_payments.remove_stale_payments(
+ duration_since_epoch, &self.pending_events
+ );
 
  // Technically we don't need to do this here, but if we have holding cell entries in a
  // channel that need freeing, it's better to do that here and block a background task
@@ -7108,6 +7127,71 @@ where
  }
 	}
 
+	/// Creates an [`OfferBuilder`] such that the [`Offer`] it builds is recognized by the
+	/// [`ChannelManager`] when handling [`InvoiceRequest`] messages for the offer. The offer will
+	/// not have an expiration unless otherwise set on the builder.
+	///
+	/// Uses a one-hop [`BlindedPath`] for the offer with [`ChannelManager::get_our_node_id`] as the
+	/// introduction node and a derived signing pubkey for recipient privacy. As such, currently,
+	/// the node must be announced. Otherwise, there is no way to find a path to the introduction
+	/// node in order to send the [`InvoiceRequest`].
+	///
+	/// [`Offer`]: crate::offers::offer::Offer
+	/// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
+	pub fn create_offer_builder(
+ &self, description: String
+	) -> OfferBuilder<DerivedMetadata, secp256k1::All> {
+ let node_id = self.get_our_node_id();
+ let expanded_key = &self.inbound_payment_key;
+ let entropy = &*self.entropy_source;
+ let secp_ctx = &self.secp_ctx;
+ let path = self.create_one_hop_blinded_path();
+
+ OfferBuilder::deriving_signing_pubkey(description, node_id, expanded_key, entropy, secp_ctx)
+ .chain_hash(self.chain_hash)
+ .path(path)
+	}
+
+	/// Creates a [`RefundBuilder`] such that the [`Refund`] it builds is recognized by the
+	/// [`ChannelManager`] when handling [`Bolt12Invoice`] messages for the refund. The builder will
+	/// have the provided expiration set. Any changes to the expiration on the returned builder will
+	/// not be honored by [`ChannelManager`].
+	///
+	/// The provided `payment_id` is used to ensure that only one invoice is paid for the refund.
+	///
+	/// Uses a one-hop [`BlindedPath`] for the refund with [`ChannelManager::get_our_node_id`] as
+	/// the introduction node and a derived payer id for sender privacy. As such, currently, the
+	/// node must be announced. Otherwise, there is no way to find a path to the introduction node
+	/// in order to send the [`Bolt12Invoice`].
+	///
+	/// [`Refund`]: crate::offers::refund::Refund
+	/// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
+	pub fn create_refund_builder(
+ &self, description: String, amount_msats: u64, absolute_expiry: Duration,
+ payment_id: PaymentId, retry_strategy: Retry, max_total_routing_fee_msat: Option<u64>
+	) -> Result<RefundBuilder<secp256k1::All>, Bolt12SemanticError> {
+ let node_id = self.get_our_node_id();
+ let expanded_key = &self.inbound_payment_key;
+ let entropy = &*self.entropy_source;
+ let secp_ctx = &self.secp_ctx;
+ let path = self.create_one_hop_blinded_path();
+
+ let builder = RefundBuilder::deriving_payer_id(
+ description, node_id, expanded_key, entropy, secp_ctx, amount_msats, payment_id
+ )?
+ .chain_hash(self.chain_hash)
+ .absolute_expiry(absolute_expiry)
+ .path(path);
+
+ self.pending_outbound_payments
+ .add_new_awaiting_invoice(
+ payment_id, absolute_expiry, retry_strategy, max_total_routing_fee_msat,
+ )
+ .map_err(|_| Bolt12SemanticError::DuplicatePaymentId)?;
+
+ Ok(builder)
+	}
+
 	/// Gets a payment secret and payment hash for use in an invoice given to a third party wishing
 	/// to pay us.
 	///
@@ -7208,6 +7292,14 @@ where
  inbound_payment::get_payment_preimage(payment_hash, payment_secret, &self.inbound_payment_key)
 	}
 
+	/// Creates a one-hop blinded path with [`ChannelManager::get_our_node_id`] as the introduction
+	/// node.
+	fn create_one_hop_blinded_path(&self) -> BlindedPath {
+ let entropy_source = self.entropy_source.deref();
+ let secp_ctx = &self.secp_ctx;
+ BlindedPath::one_hop_for_message(self.get_our_node_id(), entropy_source, secp_ctx).unwrap()
+	}
+
 	/// Gets a fake short channel id for use in receiving [phantom node payments]. These fake scids
 	/// are used when constructing the phantom invoice's route hints.
 	///

lightning/src/ln/msgs.rs

@@ -49,7 +49,7 @@ use core::str::FromStr;
 use crate::io::{self, Cursor, Read};
 use crate::io_extras::read_to_end;
 
-use crate::events::{MessageSendEventsProvider, OnionMessageProvider};
+use crate::events::MessageSendEventsProvider;
 use crate::util::chacha20poly1305rfc::ChaChaPolyReadAdapter;
 use crate::util::logger;
 use crate::util::ser::{LengthReadable, LengthReadableArgs, Readable, ReadableArgs, Writeable, Writer, WithoutLength, FixedLengthReader, HighZeroBytesDroppedBigSize, Hostname, TransactionU16LenLimited, BigSize};
@@ -1497,17 +1497,22 @@ pub trait RoutingMessageHandler : MessageSendEventsProvider {
 	fn provided_init_features(&self, their_node_id: &PublicKey) -> InitFeatures;
 }
 
-/// A trait to describe an object that can receive onion messages.
-pub trait OnionMessageHandler : OnionMessageProvider {
+/// A handler for received [`OnionMessage`]s and for providing generated ones to send.
+pub trait OnionMessageHandler {
 	/// Handle an incoming `onion_message` message from the given peer.
 	fn handle_onion_message(&self, peer_node_id: &PublicKey, msg: &OnionMessage);
+
+	/// Returns the next pending onion message for the peer with the given node id.
+	fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<OnionMessage>;
+
 	/// Called when a connection is established with a peer. Can be used to track which peers
 	/// advertise onion message support and are online.
 	///
 	/// May return an `Err(())` if the features the peer supports are not sufficient to communicate
 	/// with us. Implementors should be somewhat conservative about doing so, however, as other
 	/// message handlers may still wish to communicate with this peer.
 	fn peer_connected(&self, their_node_id: &PublicKey, init: &Init, inbound: bool) -> Result<(), ()>;
+
 	/// Indicates a connection to the peer failed/an existing connection was lost. Allows handlers to
 	/// drop and refuse to forward onion messages to this peer.
 	fn peer_disconnected(&self, their_node_id: &PublicKey);