From: Valentine Wallace <vwallace@protonmail.com>
Date: Wed, 10 Jul 2024 17:54:05 +0000 (-0400)
Subject: Add MessageContext for async payments.
X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=commitdiff_plain;h=a3216acb7d5c36f7f7993d76612ff383992e4c14;p=rust-lightning

Add MessageContext for async payments.

This context will be used in reply paths for outbound held_htlc_available
messages, so we can authenticate the corresponding release_held_htlc messages.
---

diff --git a/lightning/src/blinded_path/message.rs b/lightning/src/blinded_path/message.rs
index 256483fec..e6aa4e340 100644
--- a/lightning/src/blinded_path/message.rs
+++ b/lightning/src/blinded_path/message.rs
@@ -280,6 +280,10 @@ pub enum MessageContext {
 	///
 	/// [`OffersMessage`]: crate::onion_message::offers::OffersMessage
 	Offers(OffersContext),
+	/// Context specific to an [`AsyncPaymentsMessage`].
+	///
+	/// [`AsyncPaymentsMessage`]: crate::onion_message::async_payments::AsyncPaymentsMessage
+	AsyncPayments(AsyncPaymentsContext),
 	/// Context specific to a [`CustomOnionMessageHandler::CustomMessage`].
 	///
 	/// [`CustomOnionMessageHandler::CustomMessage`]: crate::onion_message::messenger::CustomOnionMessageHandler::CustomMessage
@@ -363,9 +367,30 @@ pub enum OffersContext {
 	},
 }
 
+/// Contains data specific to an [`AsyncPaymentsMessage`].
+///
+/// [`AsyncPaymentsMessage`]: crate::onion_message::async_payments::AsyncPaymentsMessage
+#[derive(Clone, Debug)]
+pub enum AsyncPaymentsContext {
+	/// Context contained within the reply [`BlindedMessagePath`] we put in outbound
+	/// [`HeldHtlcAvailable`] messages, provided back to us in corresponding [`ReleaseHeldHtlc`]
+	/// messages.
+	///
+	/// [`HeldHtlcAvailable`]: crate::onion_message::async_payments::HeldHtlcAvailable
+	/// [`ReleaseHeldHtlc`]: crate::onion_message::async_payments::ReleaseHeldHtlc
+	OutboundPayment {
+		/// ID used when payment to the originating [`Offer`] was initiated. Useful for us to identify
+		/// which of our pending outbound payments should be released to its often-offline payee.
+		///
+		/// [`Offer`]: crate::offers::offer::Offer
+		payment_id: PaymentId
+	},
+}
+
 impl_writeable_tlv_based_enum!(MessageContext,
 	{0, Offers} => (),
 	{1, Custom} => (),
+	{2, AsyncPayments} => (),
 );
 
 impl_writeable_tlv_based_enum!(OffersContext,
@@ -384,6 +409,12 @@ impl_writeable_tlv_based_enum!(OffersContext,
 	},
 );
 
+impl_writeable_tlv_based_enum!(AsyncPaymentsContext,
+	(0, OutboundPayment) => {
+		(0, payment_id, required),
+	},
+);
+
 /// Construct blinded onion message hops for the given `intermediate_nodes` and `recipient_node_id`.
 pub(super) fn blinded_hops<T: secp256k1::Signing + secp256k1::Verification>(
 	secp_ctx: &Secp256k1<T>, intermediate_nodes: &[MessageForwardNode],
diff --git a/lightning/src/onion_message/messenger.rs b/lightning/src/onion_message/messenger.rs
index f44e3cb01..18522c0f3 100644
--- a/lightning/src/onion_message/messenger.rs
+++ b/lightning/src/onion_message/messenger.rs
@@ -979,6 +979,10 @@ where
 				(ParsedOnionMessageContents::Offers(_), Some(MessageContext::Offers(_))) => {
 					Ok(PeeledOnion::Receive(message, context, reply_path))
 				}
+				#[cfg(async_payments)]
+				(ParsedOnionMessageContents::AsyncPayments(_), Some(MessageContext::AsyncPayments(_))) => {
+					Ok(PeeledOnion::Receive(message, context, reply_path))
+				}
 				(ParsedOnionMessageContents::Custom(_), Some(MessageContext::Custom(_))) => {
 					Ok(PeeledOnion::Receive(message, context, reply_path))
 				}
@@ -1587,7 +1591,7 @@ where
 						let context = match context {
 							None => None,
 							Some(MessageContext::Offers(context)) => Some(context),
-							Some(MessageContext::Custom(_)) => {
+							_ => {
 								debug_assert!(false, "Checked in peel_onion_message");
 								return
 							}
@@ -1614,7 +1618,7 @@ where
 						let context = match context {
 							None => None,
 							Some(MessageContext::Custom(data)) => Some(data),
-							Some(MessageContext::Offers(_)) => {
+							_ => {
 								debug_assert!(false, "Checked in peel_onion_message");
 								return
 							}