Introduce user_custom_data

Author: shaavan

lightning/src/ln/channelmanager.rs

@@ -222,6 +222,12 @@ pub enum PendingHTLCRouting {
 		/// [`Event::PaymentClaimable::onion_fields`] as
 		/// [`RecipientOnionFields::sender_custom_tlvs`].
 		sender_custom_tlvs: Vec<(u64, Vec<u8>)>,
+		/// Custom TLVs set by the receiver in the blinded path used to reach them.
+		///
+		/// For HTLCs received by LDK, this will be exposed in
+		/// [`Event::PaymentClaimable::onion_fields`] as
+		/// [`RecipientOnionFields::user_custom_data`].
+		user_custom_data: Option<Vec<u8>>,
 		/// Set if this HTLC is the final hop in a multi-hop blinded path.
 		requires_blinded_error: bool,
 	},
@@ -252,6 +258,11 @@ pub enum PendingHTLCRouting {
 		/// For HTLCs received by LDK, these will ultimately bubble back up as
 		/// [`RecipientOnionFields::sender_custom_tlvs`].
 		sender_custom_tlvs: Vec<(u64, Vec<u8>)>,
+		/// Custom TLVs set by the receiver in the blinded path used to reach them.
+		///
+		/// For HTLCs received by LDK, these will ultimately bubble back up as
+		/// [`RecipientOnionFields::user_custom_data`].
+		user_custom_data: Option<Vec<u8>>,
 		/// Set if this HTLC is the final hop in a multi-hop blinded path.
 		requires_blinded_error: bool,
 		/// Set if we are receiving a keysend to a blinded path, meaning we created the
@@ -6119,24 +6130,25 @@ where
 									PendingHTLCRouting::Receive {
 										payment_data, payment_metadata, payment_context,
 										incoming_cltv_expiry, phantom_shared_secret, sender_custom_tlvs,
-										requires_blinded_error: _
+										user_custom_data, requires_blinded_error: _
 									} => {
 										let _legacy_hop_data = Some(payment_data.clone());
 										let onion_fields = RecipientOnionFields { payment_secret: Some(payment_data.payment_secret),
-												payment_metadata, sender_custom_tlvs };
+												payment_metadata, sender_custom_tlvs, user_custom_data };
 										(incoming_cltv_expiry, OnionPayload::Invoice { _legacy_hop_data },
 											Some(payment_data), payment_context, phantom_shared_secret, onion_fields,
 											true, None)
 									},
 									PendingHTLCRouting::ReceiveKeysend {
 										payment_data, payment_preimage, payment_metadata,
-										incoming_cltv_expiry, sender_custom_tlvs, requires_blinded_error: _,
-										has_recipient_created_payment_secret, payment_context, invoice_request,
+										incoming_cltv_expiry, sender_custom_tlvs, user_custom_data,
+										requires_blinded_error: _, has_recipient_created_payment_secret, payment_context, invoice_request,
 									} => {
 										let onion_fields = RecipientOnionFields {
 											payment_secret: payment_data.as_ref().map(|data| data.payment_secret),
 											payment_metadata,
 											sender_custom_tlvs,
+											user_custom_data
 										};
 										(incoming_cltv_expiry, OnionPayload::Spontaneous(payment_preimage),
 											payment_data, payment_context, None, onion_fields,
@@ -10645,7 +10657,7 @@ where
 	/// [`Router::create_blinded_payment_paths`].
 	fn create_blinded_payment_paths(
 		&self, amount_msats: Option<u64>, payment_secret: PaymentSecret, payment_context: PaymentContext,
-		relative_expiry_seconds: u32
+		relative_expiry_seconds: u32,
 	) -> Result<Vec<BlindedPaymentPath>, ()> {
 		let expanded_key = &self.inbound_payment_key;
 		let entropy = &*self.entropy_source;
@@ -12603,6 +12615,7 @@ impl_writeable_tlv_based_enum!(PendingHTLCRouting,
 		(5, sender_custom_tlvs, optional_vec),
 		(7, requires_blinded_error, (default_value, false)),
 		(9, payment_context, option),
+		(11, user_custom_data, option),
 	},
 	(2, ReceiveKeysend) => {
 		(0, payment_preimage, required),
@@ -12612,6 +12625,7 @@ impl_writeable_tlv_based_enum!(PendingHTLCRouting,
 		(4, payment_data, option), // Added in 0.0.116
 		(5, sender_custom_tlvs, optional_vec),
 		(7, has_recipient_created_payment_secret, (default_value, false)),
+		(9, user_custom_data, option),
 		(9, payment_context, option),
 		(11, invoice_request, option),
 	},

lightning/src/ln/functional_test_utils.rs

@@ -2659,6 +2659,7 @@ pub struct PassAlongPathArgs<'a, 'b, 'c, 'd> {
 	pub expected_preimage: Option<PaymentPreimage>,
 	pub is_probe: bool,
 	pub sender_custom_tlvs: Vec<(u64, Vec<u8>)>,
+	pub user_custom_data: Option<Vec<u8>>,
 	pub payment_metadata: Option<Vec<u8>>,
 	pub expected_failure: Option<HTLCDestination>,
 }
@@ -2671,7 +2672,7 @@ impl<'a, 'b, 'c, 'd> PassAlongPathArgs<'a, 'b, 'c, 'd> {
 		Self {
 			origin_node, expected_path, recv_value, payment_hash, payment_secret: None, event,
 			payment_claimable_expected: true, clear_recipient_events: true, expected_preimage: None,
-			is_probe: false, sender_custom_tlvs: Vec::new(), payment_metadata: None, expected_failure: None,
+			is_probe: false, sender_custom_tlvs: Vec::new(), user_custom_data: None, payment_metadata: None, expected_failure: None,
 		}
 	}
 	pub fn without_clearing_recipient_events(mut self) -> Self {
@@ -2714,7 +2715,7 @@ pub fn do_pass_along_path<'a, 'b, 'c>(args: PassAlongPathArgs) -> Option<Event>
 	let PassAlongPathArgs {
 		origin_node, expected_path, recv_value, payment_hash: our_payment_hash,
 		payment_secret: our_payment_secret, event: ev, payment_claimable_expected,
-		clear_recipient_events, expected_preimage, is_probe, sender_custom_tlvs, payment_metadata,
+		clear_recipient_events, expected_preimage, is_probe, sender_custom_tlvs, user_custom_data, payment_metadata,
 		expected_failure
 	} = args;
 
@@ -2751,6 +2752,7 @@ pub fn do_pass_along_path<'a, 'b, 'c>(args: PassAlongPathArgs) -> Option<Event>
 						assert_eq!(node.node.get_our_node_id(), receiver_node_id.unwrap());
 						assert!(onion_fields.is_some());
 						assert_eq!(onion_fields.as_ref().unwrap().sender_custom_tlvs, sender_custom_tlvs);
+						assert_eq!(onion_fields.as_ref().unwrap().user_custom_data, user_custom_data);
 						assert_eq!(onion_fields.as_ref().unwrap().payment_metadata, payment_metadata);
 						match &purpose {
 							PaymentPurpose::Bolt11InvoicePayment { payment_preimage, payment_secret, .. } => {
@@ -2882,6 +2884,7 @@ pub struct ClaimAlongRouteArgs<'a, 'b, 'c, 'd> {
 	pub skip_last: bool,
 	pub payment_preimage: PaymentPreimage,
 	pub sender_custom_tlvs: Vec<(u64, Vec<u8>)>,
+	pub user_custom_data: Option<Vec<u8>>,
 	// Allow forwarding nodes to have taken 1 msat more fee than expected based on the downstream
 	// fulfill amount.
 	//
@@ -2900,7 +2903,7 @@ impl<'a, 'b, 'c, 'd> ClaimAlongRouteArgs<'a, 'b, 'c, 'd> {
 		Self {
 			origin_node, expected_paths, expected_extra_fees: vec![0; expected_paths.len()],
 			expected_min_htlc_overpay: vec![0; expected_paths.len()], skip_last: false, payment_preimage,
-			allow_1_msat_fee_overpay: false, sender_custom_tlvs: vec![],
+			allow_1_msat_fee_overpay: false, sender_custom_tlvs: vec![], user_custom_data: None,
 		}
 	}
 	pub fn skip_last(mut self, skip_last: bool) -> Self {
@@ -2923,12 +2926,17 @@ impl<'a, 'b, 'c, 'd> ClaimAlongRouteArgs<'a, 'b, 'c, 'd> {
 		self.sender_custom_tlvs = sender_custom_tlvs;
 		self
 	}
+	pub fn with_user_custom_data(mut self, user_custom_data: Vec<u8>) -> Self {
+		self.user_custom_data = Some(user_custom_data);
+		self
+	}
 }
 
 pub fn pass_claimed_payment_along_route(args: ClaimAlongRouteArgs) -> u64 {
 	let ClaimAlongRouteArgs {
 		origin_node, expected_paths, expected_extra_fees, expected_min_htlc_overpay, skip_last,
 		payment_preimage: our_payment_preimage, allow_1_msat_fee_overpay, sender_custom_tlvs,
+		user_custom_data
 	} = args;
 	let claim_event = expected_paths[0].last().unwrap().node.get_and_clear_pending_events();
 	assert_eq!(claim_event.len(), 1);
@@ -2966,6 +2974,7 @@ pub fn pass_claimed_payment_along_route(args: ClaimAlongRouteArgs) -> u64 {
 			assert_eq!(htlcs.len(), expected_paths.len());  // One per path.
 			assert_eq!(htlcs.iter().map(|h| h.value_msat).sum::<u64>(), amount_msat);
 			assert_eq!(onion_fields.as_ref().unwrap().sender_custom_tlvs, sender_custom_tlvs);
+			assert_eq!(onion_fields.as_ref().unwrap().user_custom_data, user_custom_data);
 			check_claimed_htlcs_match_route(origin_node, expected_paths, htlcs);
 			fwd_amt_msat = amount_msat;
 		}

lightning/src/ln/max_payment_path_len_tests.rs

@@ -78,6 +78,7 @@ fn large_payment_metadata() {
 		payment_secret: Some(payment_secret),
 		payment_metadata: Some(payment_metadata.clone()),
 		sender_custom_tlvs: Vec::new(),
+		user_custom_data: None,
 	};
 	nodes[0].node.send_payment(payment_hash, recipient_onion_max_md_size.clone(), PaymentId(payment_hash.0), route_0_1.route_params.clone().unwrap(), Retry::Attempts(0)).unwrap();
 	check_added_monitors!(nodes[0], 1);
@@ -126,6 +127,7 @@ fn large_payment_metadata() {
 		payment_secret: Some(payment_secret_2),
 		payment_metadata: Some(vec![42; max_metadata_len - INTERMED_PAYLOAD_LEN_ESTIMATE]),
 		sender_custom_tlvs: Vec::new(),
+		user_custom_data: None,
 	};
 	let mut route_params_0_2 = route_0_2.route_params.clone().unwrap();
 	route_params_0_2.payment_params.max_path_length = 2;
@@ -190,7 +192,7 @@ fn one_hop_blinded_path_with_custom_tlv() {
 		intro_node_blinding_point: Some(blinded_path.blinding_point()),
 		keysend_preimage: None,
 		invoice_request: None,
-		sender_custom_tlvs: &Vec::new()
+		sender_custom_tlvs: &Vec::new(),
 	}.serialized_length();
 	let max_custom_tlv_len = 1300
 		- crate::util::ser::BigSize(CUSTOM_TLV_TYPE).serialized_length() // custom TLV type

lightning/src/ln/msgs.rs

@@ -1838,6 +1838,7 @@ mod fuzzy_internal_msgs {
 		pub keysend_preimage: Option<PaymentPreimage>,
 		pub invoice_request: Option<InvoiceRequest>,
 		pub sender_custom_tlvs: Vec<(u64, Vec<u8>)>,
+		pub user_custom_data: Option<Vec<u8>>,
 	}
 
 	pub enum InboundOnionPayload {
@@ -2796,7 +2797,7 @@ impl<'a> Writeable for OutboundOnionPayload<'a> {
 			},
 			Self::Receive {
 				ref payment_data, ref payment_metadata, ref keysend_preimage, sender_intended_htlc_amt_msat,
-				cltv_expiry_height, ref sender_custom_tlvs,
+				cltv_expiry_height, ref sender_custom_tlvs
 			} => {
 				// We need to update [`ln::outbound_payment::RecipientOnionFields::with_sender_custom_tlvs`]
 				// to reject any reserved types in the experimental range if new ones are ever
@@ -2819,7 +2820,7 @@ impl<'a> Writeable for OutboundOnionPayload<'a> {
 			},
 			Self::BlindedReceive {
 				sender_intended_htlc_amt_msat, total_msat, cltv_expiry_height, encrypted_tlvs,
-				intro_node_blinding_point, keysend_preimage, ref invoice_request, ref sender_custom_tlvs,
+				intro_node_blinding_point, keysend_preimage, ref invoice_request, ref sender_custom_tlvs
 			} => {
 				// We need to update [`ln::outbound_payment::RecipientOnionFields::with_sender_custom_tlvs`]
 				// to reject any reserved types in the experimental range if new ones are ever
@@ -2909,7 +2910,7 @@ impl<NS: Deref> ReadableArgs<(Option<PublicKey>, NS)> for InboundOnionPayload wh
 		let mut total_msat = None;
 		let mut keysend_preimage: Option<PaymentPreimage> = None;
 		let mut invoice_request: Option<InvoiceRequest> = None;
-		let mut custom_tlvs = Vec::new();
+		let mut sender_custom_tlvs = Vec::new();
 
 		let tlv_len = BigSize::read(r)?;
 		let mut rd = FixedLengthReader::new(r, tlv_len.0);
@@ -2929,12 +2930,10 @@ impl<NS: Deref> ReadableArgs<(Option<PublicKey>, NS)> for InboundOnionPayload wh
 			if msg_type < 1 << 16 { return Ok(false) }
 			let mut value = Vec::new();
 			msg_reader.read_to_limit(&mut value, u64::MAX)?;
-			custom_tlvs.push((msg_type, value));
+			sender_custom_tlvs.push((msg_type, value));
 			Ok(true)
 		});
 
-		let sender_custom_tlvs = custom_tlvs;
-
 		if amt.unwrap_or(0) > MAX_VALUE_MSAT { return Err(DecodeError::InvalidValue) }
 		if intro_node_blinding_point.is_some() && update_add_blinding_point.is_some() {
 			return Err(DecodeError::InvalidValue)
@@ -2990,6 +2989,7 @@ impl<NS: Deref> ReadableArgs<(Option<PublicKey>, NS)> for InboundOnionPayload wh
 						keysend_preimage,
 						invoice_request,
 						sender_custom_tlvs,
+						user_custom_data: None,
 					}))
 				},
 			}

lightning/src/ln/onion_payment.rs

@@ -135,20 +135,20 @@ pub(super) fn create_recv_pending_htlc_info(
 	counterparty_skimmed_fee_msat: Option<u64>, current_height: u32
 ) -> Result<PendingHTLCInfo, InboundHTLCErr> {
 	let (
-		payment_data, keysend_preimage, sender_custom_tlvs, onion_amt_msat, onion_cltv_expiry,
+		payment_data, keysend_preimage, sender_custom_tlvs, user_custom_data, onion_amt_msat, onion_cltv_expiry,
 		payment_metadata, payment_context, requires_blinded_error, has_recipient_created_payment_secret,
 		invoice_request
 	) = match hop_data {
 		msgs::InboundOnionPayload::Receive(msgs::InboundOnionReceivePayload {
 			payment_data, keysend_preimage, sender_custom_tlvs, sender_intended_htlc_amt_msat,
 			cltv_expiry_height, payment_metadata, ..
 		}) =>
-			(payment_data, keysend_preimage, sender_custom_tlvs, sender_intended_htlc_amt_msat,
+			(payment_data, keysend_preimage, sender_custom_tlvs, None, sender_intended_htlc_amt_msat,
 			 cltv_expiry_height, payment_metadata, None, false, keysend_preimage.is_none(), None),
 		msgs::InboundOnionPayload::BlindedReceive(msgs::InboundOnionBlindedReceivePayload {
 			sender_intended_htlc_amt_msat, total_msat, cltv_expiry_height, payment_secret,
 			intro_node_blinding_point, payment_constraints, payment_context, keysend_preimage,
-			sender_custom_tlvs, invoice_request
+			sender_custom_tlvs, user_custom_data, invoice_request
 		}) => {
 			check_blinded_payment_constraints(
 				sender_intended_htlc_amt_msat, cltv_expiry, &payment_constraints
@@ -161,7 +161,7 @@ pub(super) fn create_recv_pending_htlc_info(
 					}
 				})?;
 			let payment_data = msgs::FinalOnionHopData { payment_secret, total_msat };
-			(Some(payment_data), keysend_preimage, sender_custom_tlvs,
+			(Some(payment_data), keysend_preimage, sender_custom_tlvs, user_custom_data,
 			 sender_intended_htlc_amt_msat, cltv_expiry_height, None, Some(payment_context),
 			 intro_node_blinding_point.is_none(), true, invoice_request)
 		}
@@ -235,6 +235,7 @@ pub(super) fn create_recv_pending_htlc_info(
 			payment_metadata,
 			incoming_cltv_expiry: onion_cltv_expiry,
 			sender_custom_tlvs,
+			user_custom_data,
 			requires_blinded_error,
 			has_recipient_created_payment_secret,
 			payment_context,
@@ -248,6 +249,7 @@ pub(super) fn create_recv_pending_htlc_info(
 			incoming_cltv_expiry: onion_cltv_expiry,
 			phantom_shared_secret,
 			sender_custom_tlvs,
+			user_custom_data,
 			requires_blinded_error,
 		}
 	} else {