Support verifying that a static invoice matches an invreq.

Useful for ensuring that an inbound static invoice matches one of our outbound
invreqs.

Author: valentinewallace

lightning/src/offers/invoice_request.rs

@@ -807,6 +807,11 @@ impl InvoiceRequest {
 	invoice_request_accessors!(self, self.contents);
 	invoice_request_respond_with_explicit_signing_pubkey_methods!(self, self, InvoiceBuilder<ExplicitSigningPubkey>);
 	invoice_request_verify_method!(self, Self);
+
+	#[cfg(async_payments)]
+	pub(super) fn bytes(&self) -> &Vec<u8> {
+		&self.bytes
+	}
 }
 
 #[cfg(c_bindings)]

lightning/src/offers/merkle.rs

@@ -249,6 +249,7 @@ impl<'a> TlvStream<'a> {
 }
 
 /// A slice into a [`TlvStream`] for a record.
+#[derive(Eq, PartialEq)]
 pub(super) struct TlvRecord<'a> {
 	pub(super) r#type: u64,
 	type_bytes: &'a [u8],

lightning/src/offers/static_invoice.rs

@@ -19,11 +19,12 @@ use crate::offers::invoice::{
 	FallbackAddress, InvoiceTlvStream, InvoiceTlvStreamRef,
 };
 use crate::offers::invoice_macros::{invoice_accessors_common, invoice_builder_methods_common};
+use crate::offers::invoice_request::InvoiceRequest;
 use crate::offers::merkle::{
-	self, SignError, SignFn, SignatureTlvStream, SignatureTlvStreamRef, TaggedHash,
+	self, SignError, SignFn, SignatureTlvStream, SignatureTlvStreamRef, TaggedHash, TlvStream,
 };
 use crate::offers::offer::{
-	Amount, Offer, OfferContents, OfferTlvStream, OfferTlvStreamRef, Quantity,
+	Amount, Offer, OfferContents, OfferTlvStream, OfferTlvStreamRef, Quantity, OFFER_TYPES,
 };
 use crate::offers::parse::{Bolt12ParseError, Bolt12SemanticError, ParsedMessage};
 use crate::util::ser::{Iterable, SeekReadable, WithoutLength, Writeable, Writer};
@@ -310,6 +311,12 @@ impl StaticInvoice {
 	pub fn signature(&self) -> Signature {
 		self.signature
 	}
+
+	pub(crate) fn matches_invreq(&self, invreq: &InvoiceRequest) -> bool {
+		let invoice_offer_tlv_stream = TlvStream::new(&self.bytes).range(OFFER_TYPES);
+		let invreq_offer_tlv_stream = TlvStream::new(invreq.bytes()).range(OFFER_TYPES);
+		invoice_offer_tlv_stream.zip(invreq_offer_tlv_stream).all(|(tlv1, tlv2)| tlv1 == tlv2)
+	}
 }
 
 impl InvoiceContents {