blip42: add the possibility to inject conctact secret inside the pay for offer

Signed-off-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>

Author: vincenzopalazzo

lightning/src/ln/channelmanager.rs

@@ -92,6 +92,7 @@ use crate::ln::outbound_payment::{
 };
 use crate::ln::types::ChannelId;
 use crate::offers::async_receive_offer_cache::AsyncReceiveOfferCache;
+use crate::offers::contacts::ContactSecrets;
 use crate::offers::flow::{HeldHtlcReplyPath, InvreqResponseInstructions, OffersMessageFlow};
 use crate::offers::invoice::{Bolt12Invoice, UnsignedBolt12Invoice};
 use crate::offers::invoice_error::InvoiceError;
@@ -728,6 +729,9 @@ pub struct OptionalOfferPaymentParams {
 	/// will ultimately fail once all pending paths have failed (generating an
 	/// [`Event::PaymentFailed`]).
 	pub retry_strategy: Retry,
+	/// Contact secrets to include in the invoice request for BLIP-42 contact management.
+	/// If provided, these secrets will be used to establish a contact relationship with the recipient.
+	pub contact_secrects: Option<ContactSecrets>,
 }
 
 impl Default for OptionalOfferPaymentParams {
@@ -739,6 +743,7 @@ impl Default for OptionalOfferPaymentParams {
 			retry_strategy: Retry::Timeout(core::time::Duration::from_secs(2)),
 			#[cfg(not(feature = "std"))]
 			retry_strategy: Retry::Attempts(3),
+			contact_secrects: None,
 		}
 	}
 }
@@ -12944,6 +12949,7 @@ where
 			payment_id,
 			None,
 			create_pending_payment_fn,
+			optional_params.contact_secrects,
 		)
 	}
 
@@ -12973,6 +12979,7 @@ where
 			payment_id,
 			Some(offer.hrn),
 			create_pending_payment_fn,
+			optional_params.contact_secrects,
 		)
 	}
 
@@ -13015,6 +13022,7 @@ where
 			payment_id,
 			None,
 			create_pending_payment_fn,
+			optional_params.contact_secrects,
 		)
 	}
 
@@ -13023,6 +13031,7 @@ where
 		&self, offer: &Offer, quantity: Option<u64>, amount_msats: Option<u64>,
 		payer_note: Option<String>, payment_id: PaymentId,
 		human_readable_name: Option<HumanReadableName>, create_pending_payment: CPP,
+		contacts: Option<ContactSecrets>,
 	) -> Result<(), Bolt12SemanticError> {
 		let entropy = &*self.entropy_source;
 		let nonce = Nonce::from_entropy_source(entropy);
@@ -13048,6 +13057,12 @@ where
 			Some(hrn) => builder.sourced_from_human_readable_name(hrn),
 		};
 
+		let contacts = match contacts {
+			None => ContactSecrets::new(self.entropy_source.get_secure_random_bytes()),
+			Some(c) => c,
+		};
+		let builder = builder.contact_secrets(contacts.clone());
+
 		let invoice_request = builder.build_and_sign()?;
 		let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
 
@@ -15649,7 +15664,7 @@ where
 								self.pending_outbound_payments
 									.received_offer(payment_id, Some(retryable_invoice_request))
 									.map_err(|_| Bolt12SemanticError::DuplicatePaymentId)
-						});
+						}, None);
 					if offer_pay_res.is_err() {
 						// The offer we tried to pay is the canonical current offer for the name we
 						// wanted to pay. If we can't pay it, there's no way to recover so fail the

lightning/src/ln/offers_tests.rs

@@ -2521,10 +2521,6 @@ fn no_double_pay_with_stale_channelmanager() {
 // Pay and offer while adding the contacts information the invoice request!
 #[test]
 fn pay_offer_and_add_contacts_info_blip42() {
-	let mut features = channelmanager::provided_init_features(&accept_forward_cfg);
-	features.set_onion_messages_optional();
-	features.set_route_blinding_optional();
-
 	let chanmon_cfgs = create_chanmon_cfgs(2);
 	let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
 
@@ -2559,10 +2555,10 @@ fn pay_offer_and_add_contacts_info_blip42() {
 	// Probably a good place to add the information that we use for the contact secret.
 	// but need to double check if the sender of the invoice request still need to ask anything.
 	expect_recent_payment!(bob, RecentPaymentDetails::AwaitingInvoice, payment_id);
-	let onion_message = alice.onion_messenger.next_onion_message_for_peer(bob_id).unwrap();
+	let onion_message = bob.onion_messenger.next_onion_message_for_peer(alice_id).unwrap();
+	alice.onion_messenger.handle_onion_message(bob_id, &onion_message);
 
-	let (invoice_request, reply_path) = extract_invoice_request(alice, &onion_message);
-	// TODO: check if the invoice request contains the contact information.
+	let (invoice_request, _reply_path) = extract_invoice_request(alice, &onion_message);
 
 	let payment_context = PaymentContext::Bolt12Offer(Bolt12OfferContext {
 		offer_id: offer.id(),
@@ -2575,21 +2571,19 @@ fn pay_offer_and_add_contacts_info_blip42() {
 	});
 	assert_eq!(invoice_request.amount_msats(), Some(10_000_000));
 	assert_ne!(invoice_request.payer_signing_pubkey(), bob_id);
-	assert!(check_compact_path_introduction_node(&reply_path, alice, bob_id));
+	// Now we check that there are the contact secret and the
+	// contact secret is the same that we inject by bob.
+	assert!(invoice_request.contact_secret().is_some());
+	// TODO: we should check also if the contact secret is the same that we inject by bob.
 
 	let onion_message = alice.onion_messenger.next_onion_message_for_peer(bob_id).unwrap();
 	bob.onion_messenger.handle_onion_message(alice_id, &onion_message);
 
-	let (invoice, reply_path) = extract_invoice(bob, &onion_message);
+	let (invoice, _reply_path) = extract_invoice(bob, &onion_message);
 	assert_eq!(invoice.amount_msats(), 10_000_000);
 	assert_ne!(invoice.signing_pubkey(), alice_id);
 	assert!(!invoice.payment_paths().is_empty());
 
-	for path in invoice.payment_paths() {
-		assert_eq!(path.introduction_node(), &IntroductionNode::NodeId(alice_id));
-	}
-	assert!(check_compact_path_introduction_node(&reply_path, bob, alice_id));
-
 	route_bolt12_payment(bob, &[alice], &invoice);
 	expect_recent_payment!(bob, RecentPaymentDetails::Pending, payment_id);
 

lightning/src/offers/invoice_request.rs

@@ -187,7 +187,7 @@ macro_rules! invoice_request_builder_methods { (
 		InvoiceRequestContentsWithoutPayerSigningPubkey {
 			payer: PayerContents(metadata), offer, chain: None, amount_msats: None,
 			features: InvoiceRequestFeatures::empty(), quantity: None, payer_note: None,
-			offer_from_hrn: None,
+			offer_from_hrn: None, invreq_contact_secret: None,
 			#[cfg(test)]
 			experimental_bar: None,
 		}
@@ -256,6 +256,18 @@ macro_rules! invoice_request_builder_methods { (
 		$return_value
 	}
 
+	/// Sets the contact secret for BLIP-42 contact authentication.
+	///
+	/// This will include the primary secret from the [`ContactSecrets`] in the invoice request.
+	///
+	/// Successive calls to this method will override the previous setting.
+	///
+	/// [`ContactSecrets`]: crate::offers::contacts::ContactSecrets
+	pub fn contact_secrets($($self_mut)* $self: $self_type, contact_secrets: crate::offers::contacts::ContactSecrets) -> $return_type {
+		$self.invoice_request.invreq_contact_secret = Some(contact_secrets.primary_secret().to_vec());
+		$return_value
+	}
+
 	fn build_with_checks($($self_mut)* $self: $self_type) -> Result<
 		(UnsignedInvoiceRequest, Option<Keypair>, Option<&'b Secp256k1<$secp_context>>),
 		Bolt12SemanticError
@@ -691,6 +703,7 @@ pub(super) struct InvoiceRequestContentsWithoutPayerSigningPubkey {
 	quantity: Option<u64>,
 	payer_note: Option<String>,
 	offer_from_hrn: Option<HumanReadableName>,
+	invreq_contact_secret: Option<Vec<u8>>,
 	#[cfg(test)]
 	experimental_bar: Option<u64>,
 }
@@ -752,6 +765,11 @@ macro_rules! invoice_request_accessors { ($self: ident, $contents: expr) => {
 	pub fn offer_from_hrn(&$self) -> &Option<HumanReadableName> {
 		$contents.offer_from_hrn()
 	}
+
+	/// Returns the contact secret if present in the invoice request.
+	pub fn contact_secret(&$self) -> Option<&[u8]> {
+		$contents.contact_secret()
+	}
 } }
 
 impl UnsignedInvoiceRequest {
@@ -1184,6 +1202,10 @@ impl InvoiceRequestContents {
 		&self.inner.offer_from_hrn
 	}
 
+	pub(super) fn contact_secret(&self) -> Option<&[u8]> {
+		self.inner.invreq_contact_secret.as_ref().map(|secret| secret.as_slice())
+	}
+
 	pub(super) fn as_tlv_stream(&self) -> PartialInvoiceRequestTlvStreamRef<'_> {
 		let (payer, offer, mut invoice_request, experimental_offer, experimental_invoice_request) =
 			self.inner.as_tlv_stream();
@@ -1230,7 +1252,7 @@ impl InvoiceRequestContentsWithoutPayerSigningPubkey {
 		};
 
 		let experimental_invoice_request = ExperimentalInvoiceRequestTlvStreamRef {
-			invreq_contact_secret: None,
+			invreq_contact_secret: self.invreq_contact_secret.as_ref(),
 			invreq_payer_offer: None,
 			invreq_payer_bip_353_name: None,
 			#[cfg(test)]
@@ -1471,7 +1493,7 @@ impl TryFrom<PartialInvoiceRequestTlvStream> for InvoiceRequestContents {
 			},
 			experimental_offer_tlv_stream,
 			ExperimentalInvoiceRequestTlvStream {
-				invreq_contact_secret: _,
+				invreq_contact_secret,
 				invreq_payer_offer: _,
 				invreq_payer_bip_353_name: _,
 				#[cfg(test)]
@@ -1517,6 +1539,7 @@ impl TryFrom<PartialInvoiceRequestTlvStream> for InvoiceRequestContents {
 				quantity,
 				payer_note,
 				offer_from_hrn,
+				invreq_contact_secret,
 				#[cfg(test)]
 				experimental_bar,
 			},