Parse experimental offer TLV records

The BOLT12 spec defines an experimental TLV range that are allowed in
offer messages. Allow this range when parsing an offer and include those
bytes in any invoice requests. Also include those bytes when computing
an OfferId and verifying that an InvoiceRequest is for a valid Offer.

Author: jkczyz

lightning/src/offers/invoice.rs

@@ -124,7 +124,7 @@ use crate::offers::invoice_macros::invoice_builder_methods_test;
 use crate::offers::invoice_request::{EXPERIMENTAL_INVOICE_REQUEST_TYPES, INVOICE_REQUEST_PAYER_ID_TYPE, INVOICE_REQUEST_TYPES, IV_BYTES as INVOICE_REQUEST_IV_BYTES, InvoiceRequest, InvoiceRequestContents, InvoiceRequestTlvStream, InvoiceRequestTlvStreamRef};
 use crate::offers::merkle::{SignError, SignFn, SignatureTlvStream, SignatureTlvStreamRef, TaggedHash, TlvStream, self, SIGNATURE_TLV_RECORD_SIZE};
 use crate::offers::nonce::Nonce;
-use crate::offers::offer::{Amount, EXPERIMENTAL_OFFER_TYPES, OFFER_TYPES, OfferTlvStream, OfferTlvStreamRef, Quantity};
+use crate::offers::offer::{Amount, EXPERIMENTAL_OFFER_TYPES, ExperimentalOfferTlvStream, ExperimentalOfferTlvStreamRef, OFFER_TYPES, OfferTlvStream, OfferTlvStreamRef, Quantity};
 use crate::offers::parse::{Bolt12ParseError, Bolt12SemanticError, ParsedMessage};
 use crate::offers::payer::{PAYER_METADATA_TYPE, PayerTlvStream, PayerTlvStreamRef};
 use crate::offers::refund::{IV_BYTES_WITH_METADATA as REFUND_IV_BYTES_WITH_METADATA, IV_BYTES_WITHOUT_METADATA as REFUND_IV_BYTES_WITHOUT_METADATA, Refund, RefundContents};
@@ -497,7 +497,7 @@ impl UnsignedBolt12Invoice {
 		const EXPERIMENTAL_TYPES: core::ops::Range<u64> =
 			EXPERIMENTAL_OFFER_TYPES.start..EXPERIMENTAL_INVOICE_REQUEST_TYPES.end;
 
-		let (_, _, _, invoice_tlv_stream) = contents.as_tlv_stream();
+		let (_, _, _, invoice_tlv_stream, _) = contents.as_tlv_stream();
 
 		// Allocate enough space for the invoice, which will include:
 		// - all TLV records from `invreq_bytes` except signatures,
@@ -901,13 +901,17 @@ impl Bolt12Invoice {
 	}
 
 	pub(crate) fn as_tlv_stream(&self) -> FullInvoiceTlvStreamRef {
-		let (payer_tlv_stream, offer_tlv_stream, invoice_request_tlv_stream, invoice_tlv_stream) =
-			self.contents.as_tlv_stream();
+		let (
+			payer_tlv_stream, offer_tlv_stream, invoice_request_tlv_stream, invoice_tlv_stream,
+			experimental_offer_tlv_stream,
+		) = self.contents.as_tlv_stream();
 		let signature_tlv_stream = SignatureTlvStreamRef {
 			signature: Some(&self.signature),
 		};
-		(payer_tlv_stream, offer_tlv_stream, invoice_request_tlv_stream, invoice_tlv_stream,
-		 signature_tlv_stream)
+		(
+			payer_tlv_stream, offer_tlv_stream, invoice_request_tlv_stream, invoice_tlv_stream,
+			signature_tlv_stream, experimental_offer_tlv_stream,
+		)
 	}
 
 	pub(crate) fn is_for_refund_without_paths(&self) -> bool {
@@ -1145,7 +1149,7 @@ impl InvoiceContents {
 
 	fn verify<T: secp256k1::Signing>(
 		&self, bytes: &[u8], metadata: &Metadata, key: &ExpandedKey, iv_bytes: &[u8; IV_LEN],
-		secp_ctx: &Secp256k1<T>
+		secp_ctx: &Secp256k1<T>,
 	) -> Result<PaymentId, ()> {
 		const EXPERIMENTAL_TYPES: core::ops::Range<u64> =
 			EXPERIMENTAL_OFFER_TYPES.start..EXPERIMENTAL_INVOICE_REQUEST_TYPES.end;
@@ -1168,13 +1172,13 @@ impl InvoiceContents {
 	}
 
 	fn as_tlv_stream(&self) -> PartialInvoiceTlvStreamRef {
-		let (payer, offer, invoice_request) = match self {
+		let (payer, offer, invoice_request, experimental_offer) = match self {
 			InvoiceContents::ForOffer { invoice_request, .. } => invoice_request.as_tlv_stream(),
 			InvoiceContents::ForRefund { refund, .. } => refund.as_tlv_stream(),
 		};
 		let invoice = self.fields().as_tlv_stream();
 
-		(payer, offer, invoice_request, invoice)
+		(payer, offer, invoice_request, invoice, experimental_offer)
 	}
 }
 
@@ -1333,15 +1337,18 @@ pub(super) struct FallbackAddress {
 
 impl_writeable!(FallbackAddress, { version, program });
 
-type FullInvoiceTlvStream =
-	(PayerTlvStream, OfferTlvStream, InvoiceRequestTlvStream, InvoiceTlvStream, SignatureTlvStream);
+type FullInvoiceTlvStream =(
+	PayerTlvStream, OfferTlvStream, InvoiceRequestTlvStream, InvoiceTlvStream, SignatureTlvStream,
+	ExperimentalOfferTlvStream,
+);
 
 type FullInvoiceTlvStreamRef<'a> = (
 	PayerTlvStreamRef<'a>,
 	OfferTlvStreamRef<'a>,
 	InvoiceRequestTlvStreamRef<'a>,
 	InvoiceTlvStreamRef<'a>,
 	SignatureTlvStreamRef<'a>,
+	ExperimentalOfferTlvStreamRef,
 );
 
 impl CursorReadable for FullInvoiceTlvStream {
@@ -1351,19 +1358,23 @@ impl CursorReadable for FullInvoiceTlvStream {
 		let invoice_request = CursorReadable::read(r)?;
 		let invoice = CursorReadable::read(r)?;
 		let signature = CursorReadable::read(r)?;
+		let experimental_offer = CursorReadable::read(r)?;
 
-		Ok((payer, offer, invoice_request, invoice, signature))
+		Ok((payer, offer, invoice_request, invoice, signature, experimental_offer))
 	}
 }
 
-type PartialInvoiceTlvStream =
-	(PayerTlvStream, OfferTlvStream, InvoiceRequestTlvStream, InvoiceTlvStream);
+type PartialInvoiceTlvStream = (
+	PayerTlvStream, OfferTlvStream, InvoiceRequestTlvStream, InvoiceTlvStream,
+	ExperimentalOfferTlvStream,
+);
 
 type PartialInvoiceTlvStreamRef<'a> = (
 	PayerTlvStreamRef<'a>,
 	OfferTlvStreamRef<'a>,
 	InvoiceRequestTlvStreamRef<'a>,
 	InvoiceTlvStreamRef<'a>,
+	ExperimentalOfferTlvStreamRef,
 );
 
 impl CursorReadable for PartialInvoiceTlvStream {
@@ -1372,8 +1383,9 @@ impl CursorReadable for PartialInvoiceTlvStream {
 		let offer = CursorReadable::read(r)?;
 		let invoice_request = CursorReadable::read(r)?;
 		let invoice = CursorReadable::read(r)?;
+		let experimental_offer = CursorReadable::read(r)?;
 
-		Ok((payer, offer, invoice_request, invoice))
+		Ok((payer, offer, invoice_request, invoice, experimental_offer))
 	}
 }
 
@@ -1385,9 +1397,13 @@ impl TryFrom<ParsedMessage<FullInvoiceTlvStream>> for Bolt12Invoice {
 		let (
 			payer_tlv_stream, offer_tlv_stream, invoice_request_tlv_stream, invoice_tlv_stream,
 			SignatureTlvStream { signature },
+			experimental_offer_tlv_stream,
 		) = tlv_stream;
 		let contents = InvoiceContents::try_from(
-			(payer_tlv_stream, offer_tlv_stream, invoice_request_tlv_stream, invoice_tlv_stream)
+			(
+				payer_tlv_stream, offer_tlv_stream, invoice_request_tlv_stream, invoice_tlv_stream,
+				experimental_offer_tlv_stream,
+			)
 		)?;
 
 		let signature = signature.ok_or(
@@ -1413,6 +1429,7 @@ impl TryFrom<PartialInvoiceTlvStream> for InvoiceContents {
 				paths, blindedpay, created_at, relative_expiry, payment_hash, amount, fallbacks,
 				features, node_id, message_paths,
 			},
+			experimental_offer_tlv_stream,
 		) = tlv_stream;
 
 		if message_paths.is_some() { return Err(Bolt12SemanticError::UnexpectedPaths) }
@@ -1445,12 +1462,18 @@ impl TryFrom<PartialInvoiceTlvStream> for InvoiceContents {
 
 		if offer_tlv_stream.issuer_id.is_none() && offer_tlv_stream.paths.is_none() {
 			let refund = RefundContents::try_from(
-				(payer_tlv_stream, offer_tlv_stream, invoice_request_tlv_stream)
+				(
+					payer_tlv_stream, offer_tlv_stream, invoice_request_tlv_stream,
+					experimental_offer_tlv_stream,
+				)
 			)?;
 			Ok(InvoiceContents::ForRefund { refund, fields })
 		} else {
 			let invoice_request = InvoiceRequestContents::try_from(
-				(payer_tlv_stream, offer_tlv_stream, invoice_request_tlv_stream)
+				(
+					payer_tlv_stream, offer_tlv_stream, invoice_request_tlv_stream,
+					experimental_offer_tlv_stream,
+				)
 			)?;
 			Ok(InvoiceContents::ForOffer { invoice_request, fields })
 		}
@@ -1525,7 +1548,7 @@ mod tests {
 	use crate::offers::invoice_request::InvoiceRequestTlvStreamRef;
 	use crate::offers::merkle::{SignError, SignatureTlvStreamRef, TaggedHash, self};
 	use crate::offers::nonce::Nonce;
-	use crate::offers::offer::{Amount, OfferTlvStreamRef, Quantity};
+	use crate::offers::offer::{Amount, ExperimentalOfferTlvStreamRef, OfferTlvStreamRef, Quantity};
 	use crate::prelude::*;
 	#[cfg(not(c_bindings))]
 	use {
@@ -1693,6 +1716,7 @@ mod tests {
 					message_paths: None,
 				},
 				SignatureTlvStreamRef { signature: Some(&invoice.signature()) },
+				ExperimentalOfferTlvStreamRef {},
 			),
 		);
 
@@ -1786,6 +1810,7 @@ mod tests {
 					message_paths: None,
 				},
 				SignatureTlvStreamRef { signature: Some(&invoice.signature()) },
+				ExperimentalOfferTlvStreamRef {},
 			),
 		);
 
@@ -1979,7 +2004,7 @@ mod tests {
 			.relative_expiry(one_hour.as_secs() as u32)
 			.build().unwrap()
 			.sign(recipient_sign).unwrap();
-		let (_, _, _, tlv_stream, _) = invoice.as_tlv_stream();
+		let (_, _, _, tlv_stream, _, _) = invoice.as_tlv_stream();
 		#[cfg(feature = "std")]
 		assert!(!invoice.is_expired());
 		assert_eq!(invoice.relative_expiry(), one_hour);
@@ -1995,7 +2020,7 @@ mod tests {
 			.relative_expiry(one_hour.as_secs() as u32 - 1)
 			.build().unwrap()
 			.sign(recipient_sign).unwrap();
-		let (_, _, _, tlv_stream, _) = invoice.as_tlv_stream();
+		let (_, _, _, tlv_stream, _, _) = invoice.as_tlv_stream();
 		#[cfg(feature = "std")]
 		assert!(invoice.is_expired());
 		assert_eq!(invoice.relative_expiry(), one_hour - Duration::from_secs(1));
@@ -2014,7 +2039,7 @@ mod tests {
 			.respond_with_no_std(payment_paths(), payment_hash(), now()).unwrap()
 			.build().unwrap()
 			.sign(recipient_sign).unwrap();
-		let (_, _, _, tlv_stream, _) = invoice.as_tlv_stream();
+		let (_, _, _, tlv_stream, _, _) = invoice.as_tlv_stream();
 		assert_eq!(invoice.amount_msats(), 1001);
 		assert_eq!(tlv_stream.amount, Some(1001));
 	}
@@ -2032,7 +2057,7 @@ mod tests {
 			.respond_with_no_std(payment_paths(), payment_hash(), now()).unwrap()
 			.build().unwrap()
 			.sign(recipient_sign).unwrap();
-		let (_, _, _, tlv_stream, _) = invoice.as_tlv_stream();
+		let (_, _, _, tlv_stream, _, _) = invoice.as_tlv_stream();
 		assert_eq!(invoice.amount_msats(), 2000);
 		assert_eq!(tlv_stream.amount, Some(2000));
 
@@ -2070,7 +2095,7 @@ mod tests {
 			.fallback_v1_p2tr_tweaked(&tweaked_pubkey)
 			.build().unwrap()
 			.sign(recipient_sign).unwrap();
-		let (_, _, _, tlv_stream, _) = invoice.as_tlv_stream();
+		let (_, _, _, tlv_stream, _, _) = invoice.as_tlv_stream();
 		assert_eq!(
 			invoice.fallbacks(),
 			vec![
@@ -2113,7 +2138,7 @@ mod tests {
 			.allow_mpp()
 			.build().unwrap()
 			.sign(recipient_sign).unwrap();
-		let (_, _, _, tlv_stream, _) = invoice.as_tlv_stream();
+		let (_, _, _, tlv_stream, _, _) = invoice.as_tlv_stream();
 		assert_eq!(invoice.invoice_features(), &features);
 		assert_eq!(tlv_stream.features, Some(&features));
 	}