Include OffersContext in Event::InvoiceReceived

When authenticating that an invoice is for a valid invoice request, the
payer metadata is needed. Some of this data will be removed in the next
commit and instead be included in the message context of the request's
reply path. Add this data to Event::InvoiceReceived so that asynchronous
invoice handling can verify properly.

Author: jkczyz

lightning/src/blinded_path/message.rs

@@ -106,7 +106,7 @@ pub enum MessageContext {
 /// Contains the data specific to [`OffersMessage`]
 ///
 /// [`OffersMessage`]: crate::onion_message::offers::OffersMessage
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, Eq, PartialEq)]
 pub enum OffersContext {
 	/// Represents an unknown BOLT12 payment context.
 	///

lightning/src/events/mod.rs

@@ -18,6 +18,7 @@ pub mod bump_transaction;
 
 pub use bump_transaction::BumpTransactionEvent;
 
+use crate::blinded_path::message::OffersContext;
 use crate::blinded_path::payment::{Bolt12OfferContext, Bolt12RefundContext, PaymentContext, PaymentContextRef};
 use crate::chain::transaction;
 use crate::ln::channelmanager::{InterceptId, PaymentId, RecipientOnionFields};
@@ -756,6 +757,8 @@ pub enum Event {
 		payment_id: PaymentId,
 		/// The invoice to pay.
 		invoice: Bolt12Invoice,
+		/// The context of the [`BlindedPath`] used to send the invoice.
+		context: OffersContext,
 		/// A responder for replying with an [`InvoiceError`] if needed.
 		///
 		/// `None` if the invoice wasn't sent with a reply path.
@@ -1522,12 +1525,13 @@ impl Writeable for Event {
 					(0, peer_node_id, required),
 				});
 			},
-			&Event::InvoiceReceived { ref payment_id, ref invoice, ref responder } => {
+			&Event::InvoiceReceived { ref payment_id, ref invoice, ref context, ref responder } => {
 				41u8.write(writer)?;
 				write_tlv_fields!(writer, {
 					(0, payment_id, required),
 					(2, invoice, required),
-					(4, responder, option),
+					(4, context, required),
+					(6, responder, option),
 				})
 			},
 			// Note that, going forward, all new events must only write data inside of
@@ -1971,11 +1975,13 @@ impl MaybeReadable for Event {
 					_init_and_read_len_prefixed_tlv_fields!(reader, {
 						(0, payment_id, required),
 						(2, invoice, required),
-						(4, responder, option),
+						(4, context, required),
+						(6, responder, option),
 					});
 					Ok(Some(Event::InvoiceReceived {
 						payment_id: payment_id.0.unwrap(),
 						invoice: invoice.0.unwrap(),
+						context: context.0.unwrap(),
 						responder,
 					}))
 				};

lightning/src/ln/channelmanager.rs

@@ -10652,7 +10652,9 @@ where
 					if invoice.invoice_features().requires_unknown_bits_from(&features) {
 						Err(InvoiceError::from(Bolt12SemanticError::UnknownRequiredFeatures))
 					} else if self.default_configuration.manually_handle_bolt12_invoices {
-						let event = Event::InvoiceReceived { payment_id, invoice, responder };
+						let event = Event::InvoiceReceived {
+							payment_id, invoice, context, responder,
+						};
 						self.pending_events.lock().unwrap().push_back((event, None));
 						return ResponseInstruction::NoResponse;
 					} else {

lightning/src/offers/nonce.rs

@@ -26,7 +26,7 @@ use crate::prelude::*;
 /// [`Offer::metadata`]: crate::offers::offer::Offer::metadata
 /// [`Offer::signing_pubkey`]: crate::offers::offer::Offer::signing_pubkey
 /// [`ExpandedKey`]: crate::ln::inbound_payment::ExpandedKey
-#[derive(Clone, Copy, Debug, PartialEq)]
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
 pub struct Nonce(pub(crate) [u8; Self::LENGTH]);
 
 impl Nonce {