Route blinding MVP

fuzz/src/onion_hop_data.rs

@@ -11,18 +11,21 @@
 // To modify it, modify msg_target_template.txt and run gen_target.sh instead.
 
 use crate::utils::test_logger;
+use lightning::util::test_utils;
 
 #[inline]
 pub fn onion_hop_data_test<Out: test_logger::Output>(data: &[u8], _out: Out) {
-	use lightning::util::ser::Readable;
+	use lightning::util::ser::ReadableArgs;
 	let mut r = ::std::io::Cursor::new(data);
-	let _ = <lightning::ln::msgs::InboundOnionPayload as Readable>::read(&mut r);
+	let node_signer = test_utils::TestNodeSigner::new(test_utils::privkey(42));
+	let _ = <lightning::ln::msgs::InboundOnionPayload as ReadableArgs<&&test_utils::TestNodeSigner>>::read(&mut r, &&node_signer);
 }
 
 #[no_mangle]
 pub extern "C" fn onion_hop_data_run(data: *const u8, datalen: usize) {
-	use lightning::util::ser::Readable;
+	use lightning::util::ser::ReadableArgs;
 	let data = unsafe { std::slice::from_raw_parts(data, datalen) };
 	let mut r = ::std::io::Cursor::new(data);
-	let _ = <lightning::ln::msgs::InboundOnionPayload as Readable>::read(&mut r);
+	let node_signer = test_utils::TestNodeSigner::new(test_utils::privkey(42));
+	let _ = <lightning::ln::msgs::InboundOnionPayload as ReadableArgs<&&test_utils::TestNodeSigner>>::read(&mut r, &&node_signer);
 }

lightning/src/blinded_path/mod.rs

@@ -76,6 +76,19 @@ impl BlindedPath {
  })
 	}
 
+	/// Create a one-hop blinded path for a payment.
+	pub fn one_hop_for_payment<ES: EntropySource, T: secp256k1::Signing + secp256k1::Verification>(
+ payee_node_id: PublicKey, payee_tlvs: payment::ReceiveTlvs, entropy_source: &ES,
+ secp_ctx: &Secp256k1<T>
+	) -> Result<(BlindedPayInfo, Self), ()> {
+ // This value is not considered in pathfinding for 1-hop blinded paths, because it's intended to
+ // be in relation to a specific channel.
+ let htlc_maximum_msat = u64::max_value();
+ Self::new_for_payment(
+ &[], payee_node_id, payee_tlvs, htlc_maximum_msat, entropy_source, secp_ctx
+ )
+	}
+
 	/// Create a blinded path for a payment, to be forwarded along `intermediate_nodes`.
 	///
 	/// Errors if:
@@ -85,7 +98,7 @@ impl BlindedPath {
 	///
 	/// [`ForwardTlvs`]: crate::blinded_path::payment::ForwardTlvs
 	// TODO: make all payloads the same size with padding + add dummy hops
-	pub fn new_for_payment<ES: EntropySource, T: secp256k1::Signing + secp256k1::Verification>(
+	pub(crate) fn new_for_payment<ES: EntropySource, T: secp256k1::Signing + secp256k1::Verification>(
  intermediate_nodes: &[payment::ForwardNode], payee_node_id: PublicKey,
  payee_tlvs: payment::ReceiveTlvs, htlc_maximum_msat: u64, entropy_source: &ES,
  secp_ctx: &Secp256k1<T>

lightning/src/blinded_path/payment.rs

@@ -119,6 +119,21 @@ impl Writeable for ReceiveTlvs {
 	}
 }
 
+// This will be removed once we support forwarding blinded HTLCs, because we'll always read a
+// `BlindedPaymentTlvs` instead.
+impl Readable for ReceiveTlvs {
+	fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
+ _init_and_read_tlv_stream!(r, {
+ (12, payment_constraints, required),
+ (65536, payment_secret, required),
+ });
+ Ok(Self {
+ payment_secret: payment_secret.0.unwrap(),
+ payment_constraints: payment_constraints.0.unwrap()
+ })
+	}
+}
+
 impl<'a> Writeable for BlindedPaymentTlvsRef<'a> {
 	fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
  // TODO: write padding

lightning/src/ln/blinded_payment_tests.rs

@@ -0,0 +1,113 @@
+// This file is Copyright its original authors, visible in version control
+// history.
+//
+// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
+// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
+// You may not use this file except in accordance with one or both of these
+// licenses.
+
+use bitcoin::secp256k1::Secp256k1;
+use crate::blinded_path::BlindedPath;
+use crate::blinded_path::payment::{PaymentConstraints, ReceiveTlvs};
+use crate::events::MessageSendEventsProvider;
+use crate::ln::channelmanager;
+use crate::ln::channelmanager::{PaymentId, RecipientOnionFields};
+use crate::ln::features::Bolt12InvoiceFeatures;
+use crate::ln::functional_test_utils::*;
+use crate::ln::outbound_payment::Retry;
+use crate::prelude::*;
+use crate::routing::router::{PaymentParameters, RouteParameters};
+use crate::util::config::UserConfig;
+
+#[test]
+fn one_hop_blinded_path() {
+	do_one_hop_blinded_path(true);
+	do_one_hop_blinded_path(false);
+}
+
+fn do_one_hop_blinded_path(success: bool) {
+	let chanmon_cfgs = create_chanmon_cfgs(2);
+	let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
+	let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
+	let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
+	let chan_upd = create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0).0.contents;
+
+	let amt_msat = 5000;
+	let (payment_preimage, payment_hash, payment_secret) = get_payment_preimage_hash(&nodes[1], Some(amt_msat), None);
+	let payee_tlvs = ReceiveTlvs {
+ payment_secret,
+ payment_constraints: PaymentConstraints {
+ max_cltv_expiry: u32::max_value(),
+ htlc_minimum_msat: chan_upd.htlc_minimum_msat,
+ },
+	};
+	let mut secp_ctx = Secp256k1::new();
+	let blinded_path = BlindedPath::one_hop_for_payment(
+ nodes[1].node.get_our_node_id(), payee_tlvs, &chanmon_cfgs[1].keys_manager, &secp_ctx
+	).unwrap();
+
+	let route_params = RouteParameters {
+ payment_params: PaymentParameters::blinded(vec![blinded_path]),
+ final_value_msat: amt_msat
+	};
+	nodes[0].node.send_payment(payment_hash, RecipientOnionFields::spontaneous_empty(),
+	PaymentId(payment_hash.0), route_params, Retry::Attempts(0)).unwrap();
+	check_added_monitors(&nodes[0], 1);
+	pass_along_route(&nodes[0], &[&[&nodes[1]]], amt_msat, payment_hash, payment_secret);
+	if success {
+ claim_payment(&nodes[0], &[&nodes[1]], payment_preimage);
+	} else {
+ fail_payment(&nodes[0], &[&nodes[1]], payment_hash);
+	}
+}
+
+#[test]
+fn mpp_to_one_hop_blinded_path() {
+	let chanmon_cfgs = create_chanmon_cfgs(4);
+	let node_cfgs = create_node_cfgs(4, &chanmon_cfgs);
+	let node_chanmgrs = create_node_chanmgrs(4, &node_cfgs, &[None, None, None, None]);
+	let nodes = create_network(4, &node_cfgs, &node_chanmgrs);
+	let mut secp_ctx = Secp256k1::new();
+
+	create_announced_chan_between_nodes(&nodes, 0, 1);
+	create_announced_chan_between_nodes(&nodes, 0, 2);
+	let chan_upd_1_3 = create_announced_chan_between_nodes(&nodes, 1, 3).0.contents;
+	create_announced_chan_between_nodes(&nodes, 2, 3).0.contents;
+
+	let amt_msat = 15_000_000;
+	let (payment_preimage, payment_hash, payment_secret) = get_payment_preimage_hash(&nodes[3], Some(amt_msat), None);
+	let payee_tlvs = ReceiveTlvs {
+ payment_secret,
+ payment_constraints: PaymentConstraints {
+ max_cltv_expiry: u32::max_value(),
+ htlc_minimum_msat: chan_upd_1_3.htlc_minimum_msat,
+ },
+	};
+	let blinded_path = BlindedPath::one_hop_for_payment(
+ nodes[3].node.get_our_node_id(), payee_tlvs, &chanmon_cfgs[3].keys_manager, &secp_ctx
+	).unwrap();
+
+	let bolt12_features: Bolt12InvoiceFeatures =
+ channelmanager::provided_invoice_features(&UserConfig::default()).to_context();
+	let route_params = RouteParameters {
+ payment_params: PaymentParameters::blinded(vec![blinded_path])
+ .with_bolt12_features(bolt12_features).unwrap(),
+ final_value_msat: amt_msat,
+	};
+	nodes[0].node.send_payment(payment_hash, RecipientOnionFields::spontaneous_empty(), PaymentId(payment_hash.0), route_params, Retry::Attempts(0)).unwrap();
+	check_added_monitors(&nodes[0], 2);
+
+	let expected_route: &[&[&Node]] = &[&[&nodes[1], &nodes[3]], &[&nodes[2], &nodes[3]]];
+	let mut events = nodes[0].node.get_and_clear_pending_msg_events();
+	assert_eq!(events.len(), 2);
+
+	let ev = remove_first_msg_event_to_node(&nodes[1].node.get_our_node_id(), &mut events);
+	pass_along_path(&nodes[0], expected_route[0], amt_msat, payment_hash.clone(),
+ Some(payment_secret), ev.clone(), false, None);
+
+	let ev = remove_first_msg_event_to_node(&nodes[2].node.get_our_node_id(), &mut events);
+	pass_along_path(&nodes[0], expected_route[1], amt_msat, payment_hash.clone(),
+ Some(payment_secret), ev.clone(), true, None);
+	claim_payment_along_route(&nodes[0], expected_route, false, payment_preimage);
+}

lightning/src/ln/channelmanager.rs

@@ -2738,7 +2738,7 @@ where
  let (short_channel_id, amt_to_forward, outgoing_cltv_value) = match hop_data {
  msgs::InboundOnionPayload::Forward { short_channel_id, amt_to_forward, outgoing_cltv_value } =>
  (short_channel_id, amt_to_forward, outgoing_cltv_value),
- msgs::InboundOnionPayload::Receive { .. } =>
+ msgs::InboundOnionPayload::Receive { .. } | msgs::InboundOnionPayload::BlindedReceive { .. } =>
  return Err(InboundOnionErr {
  msg: "Final Node OnionHopData provided for us as an intermediary node",
  err_code: 0x4000 | 22,
@@ -2770,12 +2770,19 @@ where
  payment_data, keysend_preimage, custom_tlvs, amt_msat, outgoing_cltv_value, payment_metadata, ..
  } =>
  (payment_data, keysend_preimage, custom_tlvs, amt_msat, outgoing_cltv_value, payment_metadata),
- _ =>
+ msgs::InboundOnionPayload::BlindedReceive {
+ amt_msat, total_msat, outgoing_cltv_value, payment_secret, ..
+ } => {
+ let payment_data = msgs::FinalOnionHopData { payment_secret, total_msat };
+ (Some(payment_data), None, Vec::new(), amt_msat, outgoing_cltv_value, None)
+ }
+ msgs::InboundOnionPayload::Forward { .. } => {
  return Err(InboundOnionErr {
  err_code: 0x4000|22,
  err_data: Vec::new(),
  msg: "Got non final data with an HMAC of 0",
- }),
+ })
+ },
  };
  // final_incorrect_cltv_expiry
  if outgoing_cltv_value > cltv_expiry {
@@ -2915,7 +2922,10 @@ where
  }
  }
 
- let next_hop = match onion_utils::decode_next_payment_hop(shared_secret, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac, msg.payment_hash) {
+ let next_hop = match onion_utils::decode_next_payment_hop(
+ shared_secret, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac,
+ msg.payment_hash, &self.node_signer
+ ) {
  Ok(res) => res,
  Err(onion_utils::OnionDecodeErr::Malformed { err_msg, err_code }) => {
  return_malformed_err!(err_msg, err_code);
@@ -2937,7 +2947,9 @@ where
  // We'll do receive checks in [`Self::construct_pending_htlc_info`] so we have access to the
  // inbound channel's state.
  onion_utils::Hop::Receive { .. } => return Ok((next_hop, shared_secret, None)),
- onion_utils::Hop::Forward { next_hop_data: msgs::InboundOnionPayload::Receive { .. }, .. } => {
+ onion_utils::Hop::Forward { next_hop_data: msgs::InboundOnionPayload::Receive { .. }, .. } |
+ onion_utils::Hop::Forward { next_hop_data: msgs::InboundOnionPayload::BlindedReceive { .. }, .. } =>
+ {
  return_err!("Final Node OnionHopData provided for us as an intermediary node", 0x4000 | 22, &[0; 0]);
  }
  };
@@ -3924,7 +3936,10 @@ where
  let phantom_pubkey_res = self.node_signer.get_node_id(Recipient::PhantomNode);
  if phantom_pubkey_res.is_ok() && fake_scid::is_valid_phantom(&self.fake_scid_rand_bytes, short_chan_id, &self.genesis_hash) {
  let phantom_shared_secret = self.node_signer.ecdh(Recipient::PhantomNode, &onion_packet.public_key.unwrap(), None).unwrap().secret_bytes();
- let next_hop = match onion_utils::decode_next_payment_hop(phantom_shared_secret, &onion_packet.hop_data, onion_packet.hmac, payment_hash) {
+ let next_hop = match onion_utils::decode_next_payment_hop(
+ phantom_shared_secret, &onion_packet.hop_data, onion_packet.hmac,
+ payment_hash, &self.node_signer
+ ) {
  Ok(res) => res,
  Err(onion_utils::OnionDecodeErr::Malformed { err_msg, err_code }) => {
  let sha256_of_onion = Sha256::hash(&onion_packet.hop_data).into_inner();

lightning/src/ln/mod.rs

@@ -43,6 +43,9 @@ pub mod wire;
 // without the node parameter being mut. This is incorrect, and thus newer rustcs will complain
 // about an unnecessary mut. Thus, we silence the unused_mut warning in two test modules below.
 
+#[cfg(test)]
+#[allow(unused_mut)]
+mod blinded_payment_tests;
 #[cfg(test)]
 #[allow(unused_mut)]
 mod functional_tests;

fuzz/src/onion_hop_data.rs

@@ -11,18 +11,21 @@
 // To modify it, modify msg_target_template.txt and run gen_target.sh instead.
 
 use crate::utils::test_logger;
+use lightning::util::test_utils;
 
 #[inline]
 pub fn onion_hop_data_test<Out: test_logger::Output>(data: &[u8], _out: Out) {
-	use lightning::util::ser::Readable;
+	use lightning::util::ser::ReadableArgs;
 	let mut r = ::std::io::Cursor::new(data);
-	let _ = <lightning::ln::msgs::InboundOnionPayload as Readable>::read(&mut r);
+	let node_signer = test_utils::TestNodeSigner::new(test_utils::privkey(42));
+	let _ = <lightning::ln::msgs::InboundOnionPayload as ReadableArgs<&&test_utils::TestNodeSigner>>::read(&mut r, &&node_signer);
 }
 
 #[no_mangle]
 pub extern "C" fn onion_hop_data_run(data: *const u8, datalen: usize) {
-	use lightning::util::ser::Readable;
+	use lightning::util::ser::ReadableArgs;
 	let data = unsafe { std::slice::from_raw_parts(data, datalen) };
 	let mut r = ::std::io::Cursor::new(data);
-	let _ = <lightning::ln::msgs::InboundOnionPayload as Readable>::read(&mut r);
+	let node_signer = test_utils::TestNodeSigner::new(test_utils::privkey(42));
+	let _ = <lightning::ln::msgs::InboundOnionPayload as ReadableArgs<&&test_utils::TestNodeSigner>>::read(&mut r, &&node_signer);
 }

lightning/src/blinded_path/mod.rs

@@ -76,6 +76,19 @@ impl BlindedPath {
  })
 	}
 
+	/// Create a one-hop blinded path for a payment.
+	pub fn one_hop_for_payment<ES: EntropySource, T: secp256k1::Signing + secp256k1::Verification>(
+ payee_node_id: PublicKey, payee_tlvs: payment::ReceiveTlvs, entropy_source: &ES,
+ secp_ctx: &Secp256k1<T>
+	) -> Result<(BlindedPayInfo, Self), ()> {
+ // This value is not considered in pathfinding for 1-hop blinded paths, because it's intended to
+ // be in relation to a specific channel.
+ let htlc_maximum_msat = u64::max_value();
+ Self::new_for_payment(
+ &[], payee_node_id, payee_tlvs, htlc_maximum_msat, entropy_source, secp_ctx
+ )
+	}
+
 	/// Create a blinded path for a payment, to be forwarded along `intermediate_nodes`.
 	///
 	/// Errors if:
@@ -85,7 +98,7 @@ impl BlindedPath {
 	///
 	/// [`ForwardTlvs`]: crate::blinded_path::payment::ForwardTlvs
 	// TODO: make all payloads the same size with padding + add dummy hops
-	pub fn new_for_payment<ES: EntropySource, T: secp256k1::Signing + secp256k1::Verification>(
+	pub(crate) fn new_for_payment<ES: EntropySource, T: secp256k1::Signing + secp256k1::Verification>(
  intermediate_nodes: &[payment::ForwardNode], payee_node_id: PublicKey,
  payee_tlvs: payment::ReceiveTlvs, htlc_maximum_msat: u64, entropy_source: &ES,
  secp_ctx: &Secp256k1<T>

lightning/src/blinded_path/payment.rs

@@ -119,6 +119,21 @@ impl Writeable for ReceiveTlvs {
 	}
 }
 
+// This will be removed once we support forwarding blinded HTLCs, because we'll always read a
+// `BlindedPaymentTlvs` instead.
+impl Readable for ReceiveTlvs {
+	fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
+ _init_and_read_tlv_stream!(r, {
+ (12, payment_constraints, required),
+ (65536, payment_secret, required),
+ });
+ Ok(Self {
+ payment_secret: payment_secret.0.unwrap(),
+ payment_constraints: payment_constraints.0.unwrap()
+ })
+	}
+}
+
 impl<'a> Writeable for BlindedPaymentTlvsRef<'a> {
 	fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
  // TODO: write padding

lightning/src/ln/blinded_payment_tests.rs

@@ -0,0 +1,113 @@
+// This file is Copyright its original authors, visible in version control
+// history.
+//
+// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
+// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
+// You may not use this file except in accordance with one or both of these
+// licenses.
+
+use bitcoin::secp256k1::Secp256k1;
+use crate::blinded_path::BlindedPath;
+use crate::blinded_path::payment::{PaymentConstraints, ReceiveTlvs};
+use crate::events::MessageSendEventsProvider;
+use crate::ln::channelmanager;
+use crate::ln::channelmanager::{PaymentId, RecipientOnionFields};
+use crate::ln::features::Bolt12InvoiceFeatures;
+use crate::ln::functional_test_utils::*;
+use crate::ln::outbound_payment::Retry;
+use crate::prelude::*;
+use crate::routing::router::{PaymentParameters, RouteParameters};
+use crate::util::config::UserConfig;
+
+#[test]
+fn one_hop_blinded_path() {
+	do_one_hop_blinded_path(true);
+	do_one_hop_blinded_path(false);
+}
+
+fn do_one_hop_blinded_path(success: bool) {
+	let chanmon_cfgs = create_chanmon_cfgs(2);
+	let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
+	let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
+	let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
+	let chan_upd = create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0).0.contents;
+
+	let amt_msat = 5000;
+	let (payment_preimage, payment_hash, payment_secret) = get_payment_preimage_hash(&nodes[1], Some(amt_msat), None);
+	let payee_tlvs = ReceiveTlvs {
+ payment_secret,
+ payment_constraints: PaymentConstraints {
+ max_cltv_expiry: u32::max_value(),
+ htlc_minimum_msat: chan_upd.htlc_minimum_msat,
+ },
+	};
+	let mut secp_ctx = Secp256k1::new();
+	let blinded_path = BlindedPath::one_hop_for_payment(
+ nodes[1].node.get_our_node_id(), payee_tlvs, &chanmon_cfgs[1].keys_manager, &secp_ctx
+	).unwrap();
+
+	let route_params = RouteParameters {
+ payment_params: PaymentParameters::blinded(vec![blinded_path]),
+ final_value_msat: amt_msat
+	};
+	nodes[0].node.send_payment(payment_hash, RecipientOnionFields::spontaneous_empty(),
+	PaymentId(payment_hash.0), route_params, Retry::Attempts(0)).unwrap();
+	check_added_monitors(&nodes[0], 1);
+	pass_along_route(&nodes[0], &[&[&nodes[1]]], amt_msat, payment_hash, payment_secret);
+	if success {
+ claim_payment(&nodes[0], &[&nodes[1]], payment_preimage);
+	} else {
+ fail_payment(&nodes[0], &[&nodes[1]], payment_hash);
+	}
+}
+
+#[test]
+fn mpp_to_one_hop_blinded_path() {
+	let chanmon_cfgs = create_chanmon_cfgs(4);
+	let node_cfgs = create_node_cfgs(4, &chanmon_cfgs);
+	let node_chanmgrs = create_node_chanmgrs(4, &node_cfgs, &[None, None, None, None]);
+	let nodes = create_network(4, &node_cfgs, &node_chanmgrs);
+	let mut secp_ctx = Secp256k1::new();
+
+	create_announced_chan_between_nodes(&nodes, 0, 1);
+	create_announced_chan_between_nodes(&nodes, 0, 2);
+	let chan_upd_1_3 = create_announced_chan_between_nodes(&nodes, 1, 3).0.contents;
+	create_announced_chan_between_nodes(&nodes, 2, 3).0.contents;
+
+	let amt_msat = 15_000_000;
+	let (payment_preimage, payment_hash, payment_secret) = get_payment_preimage_hash(&nodes[3], Some(amt_msat), None);
+	let payee_tlvs = ReceiveTlvs {
+ payment_secret,
+ payment_constraints: PaymentConstraints {
+ max_cltv_expiry: u32::max_value(),
+ htlc_minimum_msat: chan_upd_1_3.htlc_minimum_msat,
+ },
+	};
+	let blinded_path = BlindedPath::one_hop_for_payment(
+ nodes[3].node.get_our_node_id(), payee_tlvs, &chanmon_cfgs[3].keys_manager, &secp_ctx
+	).unwrap();
+
+	let bolt12_features: Bolt12InvoiceFeatures =
+ channelmanager::provided_invoice_features(&UserConfig::default()).to_context();
+	let route_params = RouteParameters {
+ payment_params: PaymentParameters::blinded(vec![blinded_path])
+ .with_bolt12_features(bolt12_features).unwrap(),
+ final_value_msat: amt_msat,
+	};
+	nodes[0].node.send_payment(payment_hash, RecipientOnionFields::spontaneous_empty(), PaymentId(payment_hash.0), route_params, Retry::Attempts(0)).unwrap();
+	check_added_monitors(&nodes[0], 2);
+
+	let expected_route: &[&[&Node]] = &[&[&nodes[1], &nodes[3]], &[&nodes[2], &nodes[3]]];
+	let mut events = nodes[0].node.get_and_clear_pending_msg_events();
+	assert_eq!(events.len(), 2);
+
+	let ev = remove_first_msg_event_to_node(&nodes[1].node.get_our_node_id(), &mut events);
+	pass_along_path(&nodes[0], expected_route[0], amt_msat, payment_hash.clone(),
+ Some(payment_secret), ev.clone(), false, None);
+
+	let ev = remove_first_msg_event_to_node(&nodes[2].node.get_our_node_id(), &mut events);
+	pass_along_path(&nodes[0], expected_route[1], amt_msat, payment_hash.clone(),
+ Some(payment_secret), ev.clone(), true, None);
+	claim_payment_along_route(&nodes[0], expected_route, false, payment_preimage);
+}

lightning/src/ln/channelmanager.rs

@@ -2738,7 +2738,7 @@ where
  let (short_channel_id, amt_to_forward, outgoing_cltv_value) = match hop_data {
  msgs::InboundOnionPayload::Forward { short_channel_id, amt_to_forward, outgoing_cltv_value } =>
  (short_channel_id, amt_to_forward, outgoing_cltv_value),
- msgs::InboundOnionPayload::Receive { .. } =>
+ msgs::InboundOnionPayload::Receive { .. } | msgs::InboundOnionPayload::BlindedReceive { .. } =>
  return Err(InboundOnionErr {
  msg: "Final Node OnionHopData provided for us as an intermediary node",
  err_code: 0x4000 | 22,
@@ -2770,12 +2770,19 @@ where
  payment_data, keysend_preimage, custom_tlvs, amt_msat, outgoing_cltv_value, payment_metadata, ..
  } =>
  (payment_data, keysend_preimage, custom_tlvs, amt_msat, outgoing_cltv_value, payment_metadata),
- _ =>
+ msgs::InboundOnionPayload::BlindedReceive {
+ amt_msat, total_msat, outgoing_cltv_value, payment_secret, ..
+ } => {
+ let payment_data = msgs::FinalOnionHopData { payment_secret, total_msat };
+ (Some(payment_data), None, Vec::new(), amt_msat, outgoing_cltv_value, None)
+ }
+ msgs::InboundOnionPayload::Forward { .. } => {
  return Err(InboundOnionErr {
  err_code: 0x4000|22,
  err_data: Vec::new(),
  msg: "Got non final data with an HMAC of 0",
- }),
+ })
+ },
  };
  // final_incorrect_cltv_expiry
  if outgoing_cltv_value > cltv_expiry {
@@ -2915,7 +2922,10 @@ where
  }
  }
 
- let next_hop = match onion_utils::decode_next_payment_hop(shared_secret, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac, msg.payment_hash) {
+ let next_hop = match onion_utils::decode_next_payment_hop(
+ shared_secret, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac,
+ msg.payment_hash, &self.node_signer
+ ) {
  Ok(res) => res,
  Err(onion_utils::OnionDecodeErr::Malformed { err_msg, err_code }) => {
  return_malformed_err!(err_msg, err_code);
@@ -2937,7 +2947,9 @@ where
  // We'll do receive checks in [`Self::construct_pending_htlc_info`] so we have access to the
  // inbound channel's state.
  onion_utils::Hop::Receive { .. } => return Ok((next_hop, shared_secret, None)),
- onion_utils::Hop::Forward { next_hop_data: msgs::InboundOnionPayload::Receive { .. }, .. } => {
+ onion_utils::Hop::Forward { next_hop_data: msgs::InboundOnionPayload::Receive { .. }, .. } |
+ onion_utils::Hop::Forward { next_hop_data: msgs::InboundOnionPayload::BlindedReceive { .. }, .. } =>
+ {
  return_err!("Final Node OnionHopData provided for us as an intermediary node", 0x4000 | 22, &[0; 0]);
  }
  };
@@ -3924,7 +3936,10 @@ where
  let phantom_pubkey_res = self.node_signer.get_node_id(Recipient::PhantomNode);
  if phantom_pubkey_res.is_ok() && fake_scid::is_valid_phantom(&self.fake_scid_rand_bytes, short_chan_id, &self.genesis_hash) {
  let phantom_shared_secret = self.node_signer.ecdh(Recipient::PhantomNode, &onion_packet.public_key.unwrap(), None).unwrap().secret_bytes();
- let next_hop = match onion_utils::decode_next_payment_hop(phantom_shared_secret, &onion_packet.hop_data, onion_packet.hmac, payment_hash) {
+ let next_hop = match onion_utils::decode_next_payment_hop(
+ phantom_shared_secret, &onion_packet.hop_data, onion_packet.hmac,
+ payment_hash, &self.node_signer
+ ) {
  Ok(res) => res,
  Err(onion_utils::OnionDecodeErr::Malformed { err_msg, err_code }) => {
  let sha256_of_onion = Sha256::hash(&onion_packet.hop_data).into_inner();

lightning/src/ln/mod.rs

@@ -43,6 +43,9 @@ pub mod wire;
 // without the node parameter being mut. This is incorrect, and thus newer rustcs will complain
 // about an unnecessary mut. Thus, we silence the unused_mut warning in two test modules below.
 
+#[cfg(test)]
+#[allow(unused_mut)]
+mod blinded_payment_tests;
 #[cfg(test)]
 #[allow(unused_mut)]
 mod functional_tests;

fuzz/src/onion_hop_data.rs

@@ -11,18 +11,21 @@
 // To modify it, modify msg_target_template.txt and run gen_target.sh instead.
 
 use crate::utils::test_logger;
+use lightning::util::test_utils;
 
 #[inline]
 pub fn onion_hop_data_test<Out: test_logger::Output>(data: &[u8], _out: Out) {
-	use lightning::util::ser::Readable;
+	use lightning::util::ser::ReadableArgs;
 	let mut r = ::std::io::Cursor::new(data);
-	let _ = <lightning::ln::msgs::InboundOnionPayload as Readable>::read(&mut r);
+	let node_signer = test_utils::TestNodeSigner::new(test_utils::privkey(42));
+	let _ = <lightning::ln::msgs::InboundOnionPayload as ReadableArgs<&&test_utils::TestNodeSigner>>::read(&mut r, &&node_signer);
 }
 
 #[no_mangle]
 pub extern "C" fn onion_hop_data_run(data: *const u8, datalen: usize) {
-	use lightning::util::ser::Readable;
+	use lightning::util::ser::ReadableArgs;
 	let data = unsafe { std::slice::from_raw_parts(data, datalen) };
 	let mut r = ::std::io::Cursor::new(data);
-	let _ = <lightning::ln::msgs::InboundOnionPayload as Readable>::read(&mut r);
+	let node_signer = test_utils::TestNodeSigner::new(test_utils::privkey(42));
+	let _ = <lightning::ln::msgs::InboundOnionPayload as ReadableArgs<&&test_utils::TestNodeSigner>>::read(&mut r, &&node_signer);
 }

lightning/src/blinded_path/mod.rs

@@ -76,6 +76,19 @@ impl BlindedPath {
  })
 	}
 
+	/// Create a one-hop blinded path for a payment.
+	pub fn one_hop_for_payment<ES: EntropySource, T: secp256k1::Signing + secp256k1::Verification>(
+ payee_node_id: PublicKey, payee_tlvs: payment::ReceiveTlvs, entropy_source: &ES,
+ secp_ctx: &Secp256k1<T>
+	) -> Result<(BlindedPayInfo, Self), ()> {
+ // This value is not considered in pathfinding for 1-hop blinded paths, because it's intended to
+ // be in relation to a specific channel.
+ let htlc_maximum_msat = u64::max_value();
+ Self::new_for_payment(
+ &[], payee_node_id, payee_tlvs, htlc_maximum_msat, entropy_source, secp_ctx
+ )
+	}
+
 	/// Create a blinded path for a payment, to be forwarded along `intermediate_nodes`.
 	///
 	/// Errors if:
@@ -85,7 +98,7 @@ impl BlindedPath {
 	///
 	/// [`ForwardTlvs`]: crate::blinded_path::payment::ForwardTlvs
 	// TODO: make all payloads the same size with padding + add dummy hops
-	pub fn new_for_payment<ES: EntropySource, T: secp256k1::Signing + secp256k1::Verification>(
+	pub(crate) fn new_for_payment<ES: EntropySource, T: secp256k1::Signing + secp256k1::Verification>(
  intermediate_nodes: &[payment::ForwardNode], payee_node_id: PublicKey,
  payee_tlvs: payment::ReceiveTlvs, htlc_maximum_msat: u64, entropy_source: &ES,
  secp_ctx: &Secp256k1<T>

lightning/src/blinded_path/payment.rs

@@ -119,6 +119,21 @@ impl Writeable for ReceiveTlvs {
 	}
 }
 
+// This will be removed once we support forwarding blinded HTLCs, because we'll always read a
+// `BlindedPaymentTlvs` instead.
+impl Readable for ReceiveTlvs {
+	fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
+ _init_and_read_tlv_stream!(r, {
+ (12, payment_constraints, required),
+ (65536, payment_secret, required),
+ });
+ Ok(Self {
+ payment_secret: payment_secret.0.unwrap(),
+ payment_constraints: payment_constraints.0.unwrap()
+ })
+	}
+}
+
 impl<'a> Writeable for BlindedPaymentTlvsRef<'a> {
 	fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
  // TODO: write padding

lightning/src/ln/blinded_payment_tests.rs

@@ -0,0 +1,113 @@
+// This file is Copyright its original authors, visible in version control
+// history.
+//
+// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
+// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
+// You may not use this file except in accordance with one or both of these
+// licenses.
+
+use bitcoin::secp256k1::Secp256k1;
+use crate::blinded_path::BlindedPath;
+use crate::blinded_path::payment::{PaymentConstraints, ReceiveTlvs};
+use crate::events::MessageSendEventsProvider;
+use crate::ln::channelmanager;
+use crate::ln::channelmanager::{PaymentId, RecipientOnionFields};
+use crate::ln::features::Bolt12InvoiceFeatures;
+use crate::ln::functional_test_utils::*;
+use crate::ln::outbound_payment::Retry;
+use crate::prelude::*;
+use crate::routing::router::{PaymentParameters, RouteParameters};
+use crate::util::config::UserConfig;
+
+#[test]
+fn one_hop_blinded_path() {
+	do_one_hop_blinded_path(true);
+	do_one_hop_blinded_path(false);
+}
+
+fn do_one_hop_blinded_path(success: bool) {
+	let chanmon_cfgs = create_chanmon_cfgs(2);
+	let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
+	let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
+	let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
+	let chan_upd = create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0).0.contents;
+
+	let amt_msat = 5000;
+	let (payment_preimage, payment_hash, payment_secret) = get_payment_preimage_hash(&nodes[1], Some(amt_msat), None);
+	let payee_tlvs = ReceiveTlvs {
+ payment_secret,
+ payment_constraints: PaymentConstraints {
+ max_cltv_expiry: u32::max_value(),
+ htlc_minimum_msat: chan_upd.htlc_minimum_msat,
+ },
+	};
+	let mut secp_ctx = Secp256k1::new();
+	let blinded_path = BlindedPath::one_hop_for_payment(
+ nodes[1].node.get_our_node_id(), payee_tlvs, &chanmon_cfgs[1].keys_manager, &secp_ctx
+	).unwrap();
+
+	let route_params = RouteParameters {
+ payment_params: PaymentParameters::blinded(vec![blinded_path]),
+ final_value_msat: amt_msat
+	};
+	nodes[0].node.send_payment(payment_hash, RecipientOnionFields::spontaneous_empty(),
+	PaymentId(payment_hash.0), route_params, Retry::Attempts(0)).unwrap();
+	check_added_monitors(&nodes[0], 1);
+	pass_along_route(&nodes[0], &[&[&nodes[1]]], amt_msat, payment_hash, payment_secret);
+	if success {
+ claim_payment(&nodes[0], &[&nodes[1]], payment_preimage);
+	} else {
+ fail_payment(&nodes[0], &[&nodes[1]], payment_hash);
+	}
+}
+
+#[test]
+fn mpp_to_one_hop_blinded_path() {
+	let chanmon_cfgs = create_chanmon_cfgs(4);
+	let node_cfgs = create_node_cfgs(4, &chanmon_cfgs);
+	let node_chanmgrs = create_node_chanmgrs(4, &node_cfgs, &[None, None, None, None]);
+	let nodes = create_network(4, &node_cfgs, &node_chanmgrs);
+	let mut secp_ctx = Secp256k1::new();
+
+	create_announced_chan_between_nodes(&nodes, 0, 1);
+	create_announced_chan_between_nodes(&nodes, 0, 2);
+	let chan_upd_1_3 = create_announced_chan_between_nodes(&nodes, 1, 3).0.contents;
+	create_announced_chan_between_nodes(&nodes, 2, 3).0.contents;
+
+	let amt_msat = 15_000_000;
+	let (payment_preimage, payment_hash, payment_secret) = get_payment_preimage_hash(&nodes[3], Some(amt_msat), None);
+	let payee_tlvs = ReceiveTlvs {
+ payment_secret,
+ payment_constraints: PaymentConstraints {
+ max_cltv_expiry: u32::max_value(),
+ htlc_minimum_msat: chan_upd_1_3.htlc_minimum_msat,
+ },
+	};
+	let blinded_path = BlindedPath::one_hop_for_payment(
+ nodes[3].node.get_our_node_id(), payee_tlvs, &chanmon_cfgs[3].keys_manager, &secp_ctx
+	).unwrap();
+
+	let bolt12_features: Bolt12InvoiceFeatures =
+ channelmanager::provided_invoice_features(&UserConfig::default()).to_context();
+	let route_params = RouteParameters {
+ payment_params: PaymentParameters::blinded(vec![blinded_path])
+ .with_bolt12_features(bolt12_features).unwrap(),
+ final_value_msat: amt_msat,
+	};
+	nodes[0].node.send_payment(payment_hash, RecipientOnionFields::spontaneous_empty(), PaymentId(payment_hash.0), route_params, Retry::Attempts(0)).unwrap();
+	check_added_monitors(&nodes[0], 2);
+
+	let expected_route: &[&[&Node]] = &[&[&nodes[1], &nodes[3]], &[&nodes[2], &nodes[3]]];
+	let mut events = nodes[0].node.get_and_clear_pending_msg_events();
+	assert_eq!(events.len(), 2);
+
+	let ev = remove_first_msg_event_to_node(&nodes[1].node.get_our_node_id(), &mut events);
+	pass_along_path(&nodes[0], expected_route[0], amt_msat, payment_hash.clone(),
+ Some(payment_secret), ev.clone(), false, None);
+
+	let ev = remove_first_msg_event_to_node(&nodes[2].node.get_our_node_id(), &mut events);
+	pass_along_path(&nodes[0], expected_route[1], amt_msat, payment_hash.clone(),
+ Some(payment_secret), ev.clone(), true, None);
+	claim_payment_along_route(&nodes[0], expected_route, false, payment_preimage);
+}

lightning/src/ln/channelmanager.rs

@@ -2738,7 +2738,7 @@ where
  let (short_channel_id, amt_to_forward, outgoing_cltv_value) = match hop_data {
  msgs::InboundOnionPayload::Forward { short_channel_id, amt_to_forward, outgoing_cltv_value } =>
  (short_channel_id, amt_to_forward, outgoing_cltv_value),
- msgs::InboundOnionPayload::Receive { .. } =>
+ msgs::InboundOnionPayload::Receive { .. } | msgs::InboundOnionPayload::BlindedReceive { .. } =>
  return Err(InboundOnionErr {
  msg: "Final Node OnionHopData provided for us as an intermediary node",
  err_code: 0x4000 | 22,
@@ -2770,12 +2770,19 @@ where
  payment_data, keysend_preimage, custom_tlvs, amt_msat, outgoing_cltv_value, payment_metadata, ..
  } =>
  (payment_data, keysend_preimage, custom_tlvs, amt_msat, outgoing_cltv_value, payment_metadata),
- _ =>
+ msgs::InboundOnionPayload::BlindedReceive {
+ amt_msat, total_msat, outgoing_cltv_value, payment_secret, ..
+ } => {
+ let payment_data = msgs::FinalOnionHopData { payment_secret, total_msat };
+ (Some(payment_data), None, Vec::new(), amt_msat, outgoing_cltv_value, None)
+ }
+ msgs::InboundOnionPayload::Forward { .. } => {
  return Err(InboundOnionErr {
  err_code: 0x4000|22,
  err_data: Vec::new(),
  msg: "Got non final data with an HMAC of 0",
- }),
+ })
+ },
  };
  // final_incorrect_cltv_expiry
  if outgoing_cltv_value > cltv_expiry {
@@ -2915,7 +2922,10 @@ where
  }
  }
 
- let next_hop = match onion_utils::decode_next_payment_hop(shared_secret, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac, msg.payment_hash) {
+ let next_hop = match onion_utils::decode_next_payment_hop(
+ shared_secret, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac,
+ msg.payment_hash, &self.node_signer
+ ) {
  Ok(res) => res,
  Err(onion_utils::OnionDecodeErr::Malformed { err_msg, err_code }) => {
  return_malformed_err!(err_msg, err_code);
@@ -2937,7 +2947,9 @@ where
  // We'll do receive checks in [`Self::construct_pending_htlc_info`] so we have access to the
  // inbound channel's state.
  onion_utils::Hop::Receive { .. } => return Ok((next_hop, shared_secret, None)),
- onion_utils::Hop::Forward { next_hop_data: msgs::InboundOnionPayload::Receive { .. }, .. } => {
+ onion_utils::Hop::Forward { next_hop_data: msgs::InboundOnionPayload::Receive { .. }, .. } |
+ onion_utils::Hop::Forward { next_hop_data: msgs::InboundOnionPayload::BlindedReceive { .. }, .. } =>
+ {
  return_err!("Final Node OnionHopData provided for us as an intermediary node", 0x4000 | 22, &[0; 0]);
  }
  };
@@ -3924,7 +3936,10 @@ where
  let phantom_pubkey_res = self.node_signer.get_node_id(Recipient::PhantomNode);
  if phantom_pubkey_res.is_ok() && fake_scid::is_valid_phantom(&self.fake_scid_rand_bytes, short_chan_id, &self.genesis_hash) {
  let phantom_shared_secret = self.node_signer.ecdh(Recipient::PhantomNode, &onion_packet.public_key.unwrap(), None).unwrap().secret_bytes();
- let next_hop = match onion_utils::decode_next_payment_hop(phantom_shared_secret, &onion_packet.hop_data, onion_packet.hmac, payment_hash) {
+ let next_hop = match onion_utils::decode_next_payment_hop(
+ phantom_shared_secret, &onion_packet.hop_data, onion_packet.hmac,
+ payment_hash, &self.node_signer
+ ) {
  Ok(res) => res,
  Err(onion_utils::OnionDecodeErr::Malformed { err_msg, err_code }) => {
  let sha256_of_onion = Sha256::hash(&onion_packet.hop_data).into_inner();

lightning/src/ln/mod.rs

@@ -43,6 +43,9 @@ pub mod wire;
 // without the node parameter being mut. This is incorrect, and thus newer rustcs will complain
 // about an unnecessary mut. Thus, we silence the unused_mut warning in two test modules below.
 
+#[cfg(test)]
+#[allow(unused_mut)]
+mod blinded_payment_tests;
 #[cfg(test)]
 #[allow(unused_mut)]
 mod functional_tests;

fuzz/src/onion_hop_data.rs

@@ -11,18 +11,21 @@
 // To modify it, modify msg_target_template.txt and run gen_target.sh instead.
 
 use crate::utils::test_logger;
+use lightning::util::test_utils;
 
 #[inline]
 pub fn onion_hop_data_test<Out: test_logger::Output>(data: &[u8], _out: Out) {
-	use lightning::util::ser::Readable;
+	use lightning::util::ser::ReadableArgs;
 	let mut r = ::std::io::Cursor::new(data);
-	let _ = <lightning::ln::msgs::InboundOnionPayload as Readable>::read(&mut r);
+	let node_signer = test_utils::TestNodeSigner::new(test_utils::privkey(42));
+	let _ = <lightning::ln::msgs::InboundOnionPayload as ReadableArgs<&&test_utils::TestNodeSigner>>::read(&mut r, &&node_signer);
 }
 
 #[no_mangle]
 pub extern "C" fn onion_hop_data_run(data: *const u8, datalen: usize) {
-	use lightning::util::ser::Readable;
+	use lightning::util::ser::ReadableArgs;
 	let data = unsafe { std::slice::from_raw_parts(data, datalen) };
 	let mut r = ::std::io::Cursor::new(data);
-	let _ = <lightning::ln::msgs::InboundOnionPayload as Readable>::read(&mut r);
+	let node_signer = test_utils::TestNodeSigner::new(test_utils::privkey(42));
+	let _ = <lightning::ln::msgs::InboundOnionPayload as ReadableArgs<&&test_utils::TestNodeSigner>>::read(&mut r, &&node_signer);
 }

lightning/src/blinded_path/mod.rs

@@ -76,6 +76,19 @@ impl BlindedPath {
  })
 	}
 
+	/// Create a one-hop blinded path for a payment.
+	pub fn one_hop_for_payment<ES: EntropySource, T: secp256k1::Signing + secp256k1::Verification>(
+ payee_node_id: PublicKey, payee_tlvs: payment::ReceiveTlvs, entropy_source: &ES,
+ secp_ctx: &Secp256k1<T>
+	) -> Result<(BlindedPayInfo, Self), ()> {
+ // This value is not considered in pathfinding for 1-hop blinded paths, because it's intended to
+ // be in relation to a specific channel.
+ let htlc_maximum_msat = u64::max_value();
+ Self::new_for_payment(
+ &[], payee_node_id, payee_tlvs, htlc_maximum_msat, entropy_source, secp_ctx
+ )
+	}
+
 	/// Create a blinded path for a payment, to be forwarded along `intermediate_nodes`.
 	///
 	/// Errors if:
@@ -85,7 +98,7 @@ impl BlindedPath {
 	///
 	/// [`ForwardTlvs`]: crate::blinded_path::payment::ForwardTlvs
 	// TODO: make all payloads the same size with padding + add dummy hops
-	pub fn new_for_payment<ES: EntropySource, T: secp256k1::Signing + secp256k1::Verification>(
+	pub(crate) fn new_for_payment<ES: EntropySource, T: secp256k1::Signing + secp256k1::Verification>(
  intermediate_nodes: &[payment::ForwardNode], payee_node_id: PublicKey,
  payee_tlvs: payment::ReceiveTlvs, htlc_maximum_msat: u64, entropy_source: &ES,
  secp_ctx: &Secp256k1<T>

lightning/src/blinded_path/payment.rs

@@ -119,6 +119,21 @@ impl Writeable for ReceiveTlvs {
 	}
 }
 
+// This will be removed once we support forwarding blinded HTLCs, because we'll always read a
+// `BlindedPaymentTlvs` instead.
+impl Readable for ReceiveTlvs {
+	fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
+ _init_and_read_tlv_stream!(r, {
+ (12, payment_constraints, required),
+ (65536, payment_secret, required),
+ });
+ Ok(Self {
+ payment_secret: payment_secret.0.unwrap(),
+ payment_constraints: payment_constraints.0.unwrap()
+ })
+	}
+}
+
 impl<'a> Writeable for BlindedPaymentTlvsRef<'a> {
 	fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
  // TODO: write padding

lightning/src/ln/blinded_payment_tests.rs

@@ -0,0 +1,113 @@
+// This file is Copyright its original authors, visible in version control
+// history.
+//
+// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
+// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
+// You may not use this file except in accordance with one or both of these
+// licenses.
+
+use bitcoin::secp256k1::Secp256k1;
+use crate::blinded_path::BlindedPath;
+use crate::blinded_path::payment::{PaymentConstraints, ReceiveTlvs};
+use crate::events::MessageSendEventsProvider;
+use crate::ln::channelmanager;
+use crate::ln::channelmanager::{PaymentId, RecipientOnionFields};
+use crate::ln::features::Bolt12InvoiceFeatures;
+use crate::ln::functional_test_utils::*;
+use crate::ln::outbound_payment::Retry;
+use crate::prelude::*;
+use crate::routing::router::{PaymentParameters, RouteParameters};
+use crate::util::config::UserConfig;
+
+#[test]
+fn one_hop_blinded_path() {
+	do_one_hop_blinded_path(true);
+	do_one_hop_blinded_path(false);
+}
+
+fn do_one_hop_blinded_path(success: bool) {
+	let chanmon_cfgs = create_chanmon_cfgs(2);
+	let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
+	let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
+	let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
+	let chan_upd = create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0).0.contents;
+
+	let amt_msat = 5000;
+	let (payment_preimage, payment_hash, payment_secret) = get_payment_preimage_hash(&nodes[1], Some(amt_msat), None);
+	let payee_tlvs = ReceiveTlvs {
+ payment_secret,
+ payment_constraints: PaymentConstraints {
+ max_cltv_expiry: u32::max_value(),
+ htlc_minimum_msat: chan_upd.htlc_minimum_msat,
+ },
+	};
+	let mut secp_ctx = Secp256k1::new();
+	let blinded_path = BlindedPath::one_hop_for_payment(
+ nodes[1].node.get_our_node_id(), payee_tlvs, &chanmon_cfgs[1].keys_manager, &secp_ctx
+	).unwrap();
+
+	let route_params = RouteParameters {
+ payment_params: PaymentParameters::blinded(vec![blinded_path]),
+ final_value_msat: amt_msat
+	};
+	nodes[0].node.send_payment(payment_hash, RecipientOnionFields::spontaneous_empty(),
+	PaymentId(payment_hash.0), route_params, Retry::Attempts(0)).unwrap();
+	check_added_monitors(&nodes[0], 1);
+	pass_along_route(&nodes[0], &[&[&nodes[1]]], amt_msat, payment_hash, payment_secret);
+	if success {
+ claim_payment(&nodes[0], &[&nodes[1]], payment_preimage);
+	} else {
+ fail_payment(&nodes[0], &[&nodes[1]], payment_hash);
+	}
+}
+
+#[test]
+fn mpp_to_one_hop_blinded_path() {
+	let chanmon_cfgs = create_chanmon_cfgs(4);
+	let node_cfgs = create_node_cfgs(4, &chanmon_cfgs);
+	let node_chanmgrs = create_node_chanmgrs(4, &node_cfgs, &[None, None, None, None]);
+	let nodes = create_network(4, &node_cfgs, &node_chanmgrs);
+	let mut secp_ctx = Secp256k1::new();
+
+	create_announced_chan_between_nodes(&nodes, 0, 1);
+	create_announced_chan_between_nodes(&nodes, 0, 2);
+	let chan_upd_1_3 = create_announced_chan_between_nodes(&nodes, 1, 3).0.contents;
+	create_announced_chan_between_nodes(&nodes, 2, 3).0.contents;
+
+	let amt_msat = 15_000_000;
+	let (payment_preimage, payment_hash, payment_secret) = get_payment_preimage_hash(&nodes[3], Some(amt_msat), None);
+	let payee_tlvs = ReceiveTlvs {
+ payment_secret,
+ payment_constraints: PaymentConstraints {
+ max_cltv_expiry: u32::max_value(),
+ htlc_minimum_msat: chan_upd_1_3.htlc_minimum_msat,
+ },
+	};
+	let blinded_path = BlindedPath::one_hop_for_payment(
+ nodes[3].node.get_our_node_id(), payee_tlvs, &chanmon_cfgs[3].keys_manager, &secp_ctx
+	).unwrap();
+
+	let bolt12_features: Bolt12InvoiceFeatures =
+ channelmanager::provided_invoice_features(&UserConfig::default()).to_context();
+	let route_params = RouteParameters {
+ payment_params: PaymentParameters::blinded(vec![blinded_path])
+ .with_bolt12_features(bolt12_features).unwrap(),
+ final_value_msat: amt_msat,
+	};
+	nodes[0].node.send_payment(payment_hash, RecipientOnionFields::spontaneous_empty(), PaymentId(payment_hash.0), route_params, Retry::Attempts(0)).unwrap();
+	check_added_monitors(&nodes[0], 2);
+
+	let expected_route: &[&[&Node]] = &[&[&nodes[1], &nodes[3]], &[&nodes[2], &nodes[3]]];
+	let mut events = nodes[0].node.get_and_clear_pending_msg_events();
+	assert_eq!(events.len(), 2);
+
+	let ev = remove_first_msg_event_to_node(&nodes[1].node.get_our_node_id(), &mut events);
+	pass_along_path(&nodes[0], expected_route[0], amt_msat, payment_hash.clone(),
+ Some(payment_secret), ev.clone(), false, None);
+
+	let ev = remove_first_msg_event_to_node(&nodes[2].node.get_our_node_id(), &mut events);
+	pass_along_path(&nodes[0], expected_route[1], amt_msat, payment_hash.clone(),
+ Some(payment_secret), ev.clone(), true, None);
+	claim_payment_along_route(&nodes[0], expected_route, false, payment_preimage);
+}

lightning/src/ln/channelmanager.rs

@@ -2738,7 +2738,7 @@ where
  let (short_channel_id, amt_to_forward, outgoing_cltv_value) = match hop_data {
  msgs::InboundOnionPayload::Forward { short_channel_id, amt_to_forward, outgoing_cltv_value } =>
  (short_channel_id, amt_to_forward, outgoing_cltv_value),
- msgs::InboundOnionPayload::Receive { .. } =>
+ msgs::InboundOnionPayload::Receive { .. } | msgs::InboundOnionPayload::BlindedReceive { .. } =>
  return Err(InboundOnionErr {
  msg: "Final Node OnionHopData provided for us as an intermediary node",
  err_code: 0x4000 | 22,
@@ -2770,12 +2770,19 @@ where
  payment_data, keysend_preimage, custom_tlvs, amt_msat, outgoing_cltv_value, payment_metadata, ..
  } =>
  (payment_data, keysend_preimage, custom_tlvs, amt_msat, outgoing_cltv_value, payment_metadata),
- _ =>
+ msgs::InboundOnionPayload::BlindedReceive {
+ amt_msat, total_msat, outgoing_cltv_value, payment_secret, ..
+ } => {
+ let payment_data = msgs::FinalOnionHopData { payment_secret, total_msat };
+ (Some(payment_data), None, Vec::new(), amt_msat, outgoing_cltv_value, None)
+ }
+ msgs::InboundOnionPayload::Forward { .. } => {
  return Err(InboundOnionErr {
  err_code: 0x4000|22,
  err_data: Vec::new(),
  msg: "Got non final data with an HMAC of 0",
- }),
+ })
+ },
  };
  // final_incorrect_cltv_expiry
  if outgoing_cltv_value > cltv_expiry {
@@ -2915,7 +2922,10 @@ where
  }
  }
 
- let next_hop = match onion_utils::decode_next_payment_hop(shared_secret, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac, msg.payment_hash) {
+ let next_hop = match onion_utils::decode_next_payment_hop(
+ shared_secret, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac,
+ msg.payment_hash, &self.node_signer
+ ) {
  Ok(res) => res,
  Err(onion_utils::OnionDecodeErr::Malformed { err_msg, err_code }) => {
  return_malformed_err!(err_msg, err_code);
@@ -2937,7 +2947,9 @@ where
  // We'll do receive checks in [`Self::construct_pending_htlc_info`] so we have access to the
  // inbound channel's state.
  onion_utils::Hop::Receive { .. } => return Ok((next_hop, shared_secret, None)),
- onion_utils::Hop::Forward { next_hop_data: msgs::InboundOnionPayload::Receive { .. }, .. } => {
+ onion_utils::Hop::Forward { next_hop_data: msgs::InboundOnionPayload::Receive { .. }, .. } |
+ onion_utils::Hop::Forward { next_hop_data: msgs::InboundOnionPayload::BlindedReceive { .. }, .. } =>
+ {
  return_err!("Final Node OnionHopData provided for us as an intermediary node", 0x4000 | 22, &[0; 0]);
  }
  };
@@ -3924,7 +3936,10 @@ where
  let phantom_pubkey_res = self.node_signer.get_node_id(Recipient::PhantomNode);
  if phantom_pubkey_res.is_ok() && fake_scid::is_valid_phantom(&self.fake_scid_rand_bytes, short_chan_id, &self.genesis_hash) {
  let phantom_shared_secret = self.node_signer.ecdh(Recipient::PhantomNode, &onion_packet.public_key.unwrap(), None).unwrap().secret_bytes();
- let next_hop = match onion_utils::decode_next_payment_hop(phantom_shared_secret, &onion_packet.hop_data, onion_packet.hmac, payment_hash) {
+ let next_hop = match onion_utils::decode_next_payment_hop(
+ phantom_shared_secret, &onion_packet.hop_data, onion_packet.hmac,
+ payment_hash, &self.node_signer
+ ) {
  Ok(res) => res,
  Err(onion_utils::OnionDecodeErr::Malformed { err_msg, err_code }) => {
  let sha256_of_onion = Sha256::hash(&onion_packet.hop_data).into_inner();

lightning/src/ln/mod.rs

@@ -43,6 +43,9 @@ pub mod wire;
 // without the node parameter being mut. This is incorrect, and thus newer rustcs will complain
 // about an unnecessary mut. Thus, we silence the unused_mut warning in two test modules below.
 
+#[cfg(test)]
+#[allow(unused_mut)]
+mod blinded_payment_tests;
 #[cfg(test)]
 #[allow(unused_mut)]
 mod functional_tests;

fuzz/src/onion_hop_data.rs

@@ -11,18 +11,21 @@
 // To modify it, modify msg_target_template.txt and run gen_target.sh instead.
 
 use crate::utils::test_logger;
+use lightning::util::test_utils;
 
 #[inline]
 pub fn onion_hop_data_test<Out: test_logger::Output>(data: &[u8], _out: Out) {
-	use lightning::util::ser::Readable;
+	use lightning::util::ser::ReadableArgs;
 	let mut r = ::std::io::Cursor::new(data);
-	let _ = <lightning::ln::msgs::InboundOnionPayload as Readable>::read(&mut r);
+	let node_signer = test_utils::TestNodeSigner::new(test_utils::privkey(42));
+	let _ = <lightning::ln::msgs::InboundOnionPayload as ReadableArgs<&&test_utils::TestNodeSigner>>::read(&mut r, &&node_signer);
 }
 
 #[no_mangle]
 pub extern "C" fn onion_hop_data_run(data: *const u8, datalen: usize) {
-	use lightning::util::ser::Readable;
+	use lightning::util::ser::ReadableArgs;
 	let data = unsafe { std::slice::from_raw_parts(data, datalen) };
 	let mut r = ::std::io::Cursor::new(data);
-	let _ = <lightning::ln::msgs::InboundOnionPayload as Readable>::read(&mut r);
+	let node_signer = test_utils::TestNodeSigner::new(test_utils::privkey(42));
+	let _ = <lightning::ln::msgs::InboundOnionPayload as ReadableArgs<&&test_utils::TestNodeSigner>>::read(&mut r, &&node_signer);
 }

lightning/src/blinded_path/mod.rs

@@ -76,6 +76,19 @@ impl BlindedPath {
  })
 	}
 
+	/// Create a one-hop blinded path for a payment.
+	pub fn one_hop_for_payment<ES: EntropySource, T: secp256k1::Signing + secp256k1::Verification>(
+ payee_node_id: PublicKey, payee_tlvs: payment::ReceiveTlvs, entropy_source: &ES,
+ secp_ctx: &Secp256k1<T>
+	) -> Result<(BlindedPayInfo, Self), ()> {
+ // This value is not considered in pathfinding for 1-hop blinded paths, because it's intended to
+ // be in relation to a specific channel.
+ let htlc_maximum_msat = u64::max_value();
+ Self::new_for_payment(
+ &[], payee_node_id, payee_tlvs, htlc_maximum_msat, entropy_source, secp_ctx
+ )
+	}
+
 	/// Create a blinded path for a payment, to be forwarded along `intermediate_nodes`.
 	///
 	/// Errors if:
@@ -85,7 +98,7 @@ impl BlindedPath {
 	///
 	/// [`ForwardTlvs`]: crate::blinded_path::payment::ForwardTlvs
 	// TODO: make all payloads the same size with padding + add dummy hops
-	pub fn new_for_payment<ES: EntropySource, T: secp256k1::Signing + secp256k1::Verification>(
+	pub(crate) fn new_for_payment<ES: EntropySource, T: secp256k1::Signing + secp256k1::Verification>(
  intermediate_nodes: &[payment::ForwardNode], payee_node_id: PublicKey,
  payee_tlvs: payment::ReceiveTlvs, htlc_maximum_msat: u64, entropy_source: &ES,
  secp_ctx: &Secp256k1<T>

lightning/src/blinded_path/payment.rs

@@ -119,6 +119,21 @@ impl Writeable for ReceiveTlvs {
 	}
 }
 
+// This will be removed once we support forwarding blinded HTLCs, because we'll always read a
+// `BlindedPaymentTlvs` instead.
+impl Readable for ReceiveTlvs {
+	fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
+ _init_and_read_tlv_stream!(r, {
+ (12, payment_constraints, required),
+ (65536, payment_secret, required),
+ });
+ Ok(Self {
+ payment_secret: payment_secret.0.unwrap(),
+ payment_constraints: payment_constraints.0.unwrap()
+ })
+	}
+}
+
 impl<'a> Writeable for BlindedPaymentTlvsRef<'a> {
 	fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
  // TODO: write padding

lightning/src/ln/blinded_payment_tests.rs

@@ -0,0 +1,113 @@
+// This file is Copyright its original authors, visible in version control
+// history.
+//
+// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
+// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
+// You may not use this file except in accordance with one or both of these
+// licenses.
+
+use bitcoin::secp256k1::Secp256k1;
+use crate::blinded_path::BlindedPath;
+use crate::blinded_path::payment::{PaymentConstraints, ReceiveTlvs};
+use crate::events::MessageSendEventsProvider;
+use crate::ln::channelmanager;
+use crate::ln::channelmanager::{PaymentId, RecipientOnionFields};
+use crate::ln::features::Bolt12InvoiceFeatures;
+use crate::ln::functional_test_utils::*;
+use crate::ln::outbound_payment::Retry;
+use crate::prelude::*;
+use crate::routing::router::{PaymentParameters, RouteParameters};
+use crate::util::config::UserConfig;
+
+#[test]
+fn one_hop_blinded_path() {
+	do_one_hop_blinded_path(true);
+	do_one_hop_blinded_path(false);
+}
+
+fn do_one_hop_blinded_path(success: bool) {
+	let chanmon_cfgs = create_chanmon_cfgs(2);
+	let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
+	let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
+	let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
+	let chan_upd = create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0).0.contents;
+
+	let amt_msat = 5000;
+	let (payment_preimage, payment_hash, payment_secret) = get_payment_preimage_hash(&nodes[1], Some(amt_msat), None);
+	let payee_tlvs = ReceiveTlvs {
+ payment_secret,
+ payment_constraints: PaymentConstraints {
+ max_cltv_expiry: u32::max_value(),
+ htlc_minimum_msat: chan_upd.htlc_minimum_msat,
+ },
+	};
+	let mut secp_ctx = Secp256k1::new();
+	let blinded_path = BlindedPath::one_hop_for_payment(
+ nodes[1].node.get_our_node_id(), payee_tlvs, &chanmon_cfgs[1].keys_manager, &secp_ctx
+	).unwrap();
+
+	let route_params = RouteParameters {
+ payment_params: PaymentParameters::blinded(vec![blinded_path]),
+ final_value_msat: amt_msat
+	};
+	nodes[0].node.send_payment(payment_hash, RecipientOnionFields::spontaneous_empty(),
+	PaymentId(payment_hash.0), route_params, Retry::Attempts(0)).unwrap();
+	check_added_monitors(&nodes[0], 1);
+	pass_along_route(&nodes[0], &[&[&nodes[1]]], amt_msat, payment_hash, payment_secret);
+	if success {
+ claim_payment(&nodes[0], &[&nodes[1]], payment_preimage);
+	} else {
+ fail_payment(&nodes[0], &[&nodes[1]], payment_hash);
+	}
+}
+
+#[test]
+fn mpp_to_one_hop_blinded_path() {
+	let chanmon_cfgs = create_chanmon_cfgs(4);
+	let node_cfgs = create_node_cfgs(4, &chanmon_cfgs);
+	let node_chanmgrs = create_node_chanmgrs(4, &node_cfgs, &[None, None, None, None]);
+	let nodes = create_network(4, &node_cfgs, &node_chanmgrs);
+	let mut secp_ctx = Secp256k1::new();
+
+	create_announced_chan_between_nodes(&nodes, 0, 1);
+	create_announced_chan_between_nodes(&nodes, 0, 2);
+	let chan_upd_1_3 = create_announced_chan_between_nodes(&nodes, 1, 3).0.contents;
+	create_announced_chan_between_nodes(&nodes, 2, 3).0.contents;
+
+	let amt_msat = 15_000_000;
+	let (payment_preimage, payment_hash, payment_secret) = get_payment_preimage_hash(&nodes[3], Some(amt_msat), None);
+	let payee_tlvs = ReceiveTlvs {
+ payment_secret,
+ payment_constraints: PaymentConstraints {
+ max_cltv_expiry: u32::max_value(),
+ htlc_minimum_msat: chan_upd_1_3.htlc_minimum_msat,
+ },
+	};
+	let blinded_path = BlindedPath::one_hop_for_payment(
+ nodes[3].node.get_our_node_id(), payee_tlvs, &chanmon_cfgs[3].keys_manager, &secp_ctx
+	).unwrap();
+
+	let bolt12_features: Bolt12InvoiceFeatures =
+ channelmanager::provided_invoice_features(&UserConfig::default()).to_context();
+	let route_params = RouteParameters {
+ payment_params: PaymentParameters::blinded(vec![blinded_path])
+ .with_bolt12_features(bolt12_features).unwrap(),
+ final_value_msat: amt_msat,
+	};
+	nodes[0].node.send_payment(payment_hash, RecipientOnionFields::spontaneous_empty(), PaymentId(payment_hash.0), route_params, Retry::Attempts(0)).unwrap();
+	check_added_monitors(&nodes[0], 2);
+
+	let expected_route: &[&[&Node]] = &[&[&nodes[1], &nodes[3]], &[&nodes[2], &nodes[3]]];
+	let mut events = nodes[0].node.get_and_clear_pending_msg_events();
+	assert_eq!(events.len(), 2);
+
+	let ev = remove_first_msg_event_to_node(&nodes[1].node.get_our_node_id(), &mut events);
+	pass_along_path(&nodes[0], expected_route[0], amt_msat, payment_hash.clone(),
+ Some(payment_secret), ev.clone(), false, None);
+
+	let ev = remove_first_msg_event_to_node(&nodes[2].node.get_our_node_id(), &mut events);
+	pass_along_path(&nodes[0], expected_route[1], amt_msat, payment_hash.clone(),
+ Some(payment_secret), ev.clone(), true, None);
+	claim_payment_along_route(&nodes[0], expected_route, false, payment_preimage);
+}

lightning/src/ln/channelmanager.rs

@@ -2738,7 +2738,7 @@ where
  let (short_channel_id, amt_to_forward, outgoing_cltv_value) = match hop_data {
  msgs::InboundOnionPayload::Forward { short_channel_id, amt_to_forward, outgoing_cltv_value } =>
  (short_channel_id, amt_to_forward, outgoing_cltv_value),
- msgs::InboundOnionPayload::Receive { .. } =>
+ msgs::InboundOnionPayload::Receive { .. } | msgs::InboundOnionPayload::BlindedReceive { .. } =>
  return Err(InboundOnionErr {
  msg: "Final Node OnionHopData provided for us as an intermediary node",
  err_code: 0x4000 | 22,
@@ -2770,12 +2770,19 @@ where
  payment_data, keysend_preimage, custom_tlvs, amt_msat, outgoing_cltv_value, payment_metadata, ..
  } =>
  (payment_data, keysend_preimage, custom_tlvs, amt_msat, outgoing_cltv_value, payment_metadata),
- _ =>
+ msgs::InboundOnionPayload::BlindedReceive {
+ amt_msat, total_msat, outgoing_cltv_value, payment_secret, ..
+ } => {
+ let payment_data = msgs::FinalOnionHopData { payment_secret, total_msat };
+ (Some(payment_data), None, Vec::new(), amt_msat, outgoing_cltv_value, None)
+ }
+ msgs::InboundOnionPayload::Forward { .. } => {
  return Err(InboundOnionErr {
  err_code: 0x4000|22,
  err_data: Vec::new(),
  msg: "Got non final data with an HMAC of 0",
- }),
+ })
+ },
  };
  // final_incorrect_cltv_expiry
  if outgoing_cltv_value > cltv_expiry {
@@ -2915,7 +2922,10 @@ where
  }
  }
 
- let next_hop = match onion_utils::decode_next_payment_hop(shared_secret, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac, msg.payment_hash) {
+ let next_hop = match onion_utils::decode_next_payment_hop(
+ shared_secret, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac,
+ msg.payment_hash, &self.node_signer
+ ) {
  Ok(res) => res,
  Err(onion_utils::OnionDecodeErr::Malformed { err_msg, err_code }) => {
  return_malformed_err!(err_msg, err_code);
@@ -2937,7 +2947,9 @@ where
  // We'll do receive checks in [`Self::construct_pending_htlc_info`] so we have access to the
  // inbound channel's state.
  onion_utils::Hop::Receive { .. } => return Ok((next_hop, shared_secret, None)),
- onion_utils::Hop::Forward { next_hop_data: msgs::InboundOnionPayload::Receive { .. }, .. } => {
+ onion_utils::Hop::Forward { next_hop_data: msgs::InboundOnionPayload::Receive { .. }, .. } |
+ onion_utils::Hop::Forward { next_hop_data: msgs::InboundOnionPayload::BlindedReceive { .. }, .. } =>
+ {
  return_err!("Final Node OnionHopData provided for us as an intermediary node", 0x4000 | 22, &[0; 0]);
  }
  };
@@ -3924,7 +3936,10 @@ where
  let phantom_pubkey_res = self.node_signer.get_node_id(Recipient::PhantomNode);
  if phantom_pubkey_res.is_ok() && fake_scid::is_valid_phantom(&self.fake_scid_rand_bytes, short_chan_id, &self.genesis_hash) {
  let phantom_shared_secret = self.node_signer.ecdh(Recipient::PhantomNode, &onion_packet.public_key.unwrap(), None).unwrap().secret_bytes();
- let next_hop = match onion_utils::decode_next_payment_hop(phantom_shared_secret, &onion_packet.hop_data, onion_packet.hmac, payment_hash) {
+ let next_hop = match onion_utils::decode_next_payment_hop(
+ phantom_shared_secret, &onion_packet.hop_data, onion_packet.hmac,
+ payment_hash, &self.node_signer
+ ) {
  Ok(res) => res,
  Err(onion_utils::OnionDecodeErr::Malformed { err_msg, err_code }) => {
  let sha256_of_onion = Sha256::hash(&onion_packet.hop_data).into_inner();

lightning/src/ln/mod.rs

@@ -43,6 +43,9 @@ pub mod wire;
 // without the node parameter being mut. This is incorrect, and thus newer rustcs will complain
 // about an unnecessary mut. Thus, we silence the unused_mut warning in two test modules below.
 
+#[cfg(test)]
+#[allow(unused_mut)]
+mod blinded_payment_tests;
 #[cfg(test)]
 #[allow(unused_mut)]
 mod functional_tests;

fuzz/src/onion_hop_data.rs

@@ -11,18 +11,21 @@
 // To modify it, modify msg_target_template.txt and run gen_target.sh instead.
 
 use crate::utils::test_logger;
+use lightning::util::test_utils;
 
 #[inline]
 pub fn onion_hop_data_test<Out: test_logger::Output>(data: &[u8], _out: Out) {
-	use lightning::util::ser::Readable;
+	use lightning::util::ser::ReadableArgs;
 	let mut r = ::std::io::Cursor::new(data);
-	let _ = <lightning::ln::msgs::InboundOnionPayload as Readable>::read(&mut r);
+	let node_signer = test_utils::TestNodeSigner::new(test_utils::privkey(42));
+	let _ = <lightning::ln::msgs::InboundOnionPayload as ReadableArgs<&&test_utils::TestNodeSigner>>::read(&mut r, &&node_signer);
 }
 
 #[no_mangle]
 pub extern "C" fn onion_hop_data_run(data: *const u8, datalen: usize) {
-	use lightning::util::ser::Readable;
+	use lightning::util::ser::ReadableArgs;
 	let data = unsafe { std::slice::from_raw_parts(data, datalen) };
 	let mut r = ::std::io::Cursor::new(data);
-	let _ = <lightning::ln::msgs::InboundOnionPayload as Readable>::read(&mut r);
+	let node_signer = test_utils::TestNodeSigner::new(test_utils::privkey(42));
+	let _ = <lightning::ln::msgs::InboundOnionPayload as ReadableArgs<&&test_utils::TestNodeSigner>>::read(&mut r, &&node_signer);
 }

lightning/src/blinded_path/mod.rs

@@ -76,6 +76,19 @@ impl BlindedPath {
  })
 	}
 
+	/// Create a one-hop blinded path for a payment.
+	pub fn one_hop_for_payment<ES: EntropySource, T: secp256k1::Signing + secp256k1::Verification>(
+ payee_node_id: PublicKey, payee_tlvs: payment::ReceiveTlvs, entropy_source: &ES,
+ secp_ctx: &Secp256k1<T>
+	) -> Result<(BlindedPayInfo, Self), ()> {
+ // This value is not considered in pathfinding for 1-hop blinded paths, because it's intended to
+ // be in relation to a specific channel.
+ let htlc_maximum_msat = u64::max_value();
+ Self::new_for_payment(
+ &[], payee_node_id, payee_tlvs, htlc_maximum_msat, entropy_source, secp_ctx
+ )
+	}
+
 	/// Create a blinded path for a payment, to be forwarded along `intermediate_nodes`.
 	///
 	/// Errors if:
@@ -85,7 +98,7 @@ impl BlindedPath {
 	///
 	/// [`ForwardTlvs`]: crate::blinded_path::payment::ForwardTlvs
 	// TODO: make all payloads the same size with padding + add dummy hops
-	pub fn new_for_payment<ES: EntropySource, T: secp256k1::Signing + secp256k1::Verification>(
+	pub(crate) fn new_for_payment<ES: EntropySource, T: secp256k1::Signing + secp256k1::Verification>(
  intermediate_nodes: &[payment::ForwardNode], payee_node_id: PublicKey,
  payee_tlvs: payment::ReceiveTlvs, htlc_maximum_msat: u64, entropy_source: &ES,
  secp_ctx: &Secp256k1<T>

lightning/src/blinded_path/payment.rs

@@ -119,6 +119,21 @@ impl Writeable for ReceiveTlvs {
 	}
 }
 
+// This will be removed once we support forwarding blinded HTLCs, because we'll always read a
+// `BlindedPaymentTlvs` instead.
+impl Readable for ReceiveTlvs {
+	fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
+ _init_and_read_tlv_stream!(r, {
+ (12, payment_constraints, required),
+ (65536, payment_secret, required),
+ });
+ Ok(Self {
+ payment_secret: payment_secret.0.unwrap(),
+ payment_constraints: payment_constraints.0.unwrap()
+ })
+	}
+}
+
 impl<'a> Writeable for BlindedPaymentTlvsRef<'a> {
 	fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
  // TODO: write padding

lightning/src/ln/blinded_payment_tests.rs

@@ -0,0 +1,113 @@
+// This file is Copyright its original authors, visible in version control
+// history.
+//
+// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
+// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
+// You may not use this file except in accordance with one or both of these
+// licenses.
+
+use bitcoin::secp256k1::Secp256k1;
+use crate::blinded_path::BlindedPath;
+use crate::blinded_path::payment::{PaymentConstraints, ReceiveTlvs};
+use crate::events::MessageSendEventsProvider;
+use crate::ln::channelmanager;
+use crate::ln::channelmanager::{PaymentId, RecipientOnionFields};
+use crate::ln::features::Bolt12InvoiceFeatures;
+use crate::ln::functional_test_utils::*;
+use crate::ln::outbound_payment::Retry;
+use crate::prelude::*;
+use crate::routing::router::{PaymentParameters, RouteParameters};
+use crate::util::config::UserConfig;
+
+#[test]
+fn one_hop_blinded_path() {
+	do_one_hop_blinded_path(true);
+	do_one_hop_blinded_path(false);
+}
+
+fn do_one_hop_blinded_path(success: bool) {
+	let chanmon_cfgs = create_chanmon_cfgs(2);
+	let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
+	let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
+	let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
+	let chan_upd = create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0).0.contents;
+
+	let amt_msat = 5000;
+	let (payment_preimage, payment_hash, payment_secret) = get_payment_preimage_hash(&nodes[1], Some(amt_msat), None);
+	let payee_tlvs = ReceiveTlvs {
+ payment_secret,
+ payment_constraints: PaymentConstraints {
+ max_cltv_expiry: u32::max_value(),
+ htlc_minimum_msat: chan_upd.htlc_minimum_msat,
+ },
+	};
+	let mut secp_ctx = Secp256k1::new();
+	let blinded_path = BlindedPath::one_hop_for_payment(
+ nodes[1].node.get_our_node_id(), payee_tlvs, &chanmon_cfgs[1].keys_manager, &secp_ctx
+	).unwrap();
+
+	let route_params = RouteParameters {
+ payment_params: PaymentParameters::blinded(vec![blinded_path]),
+ final_value_msat: amt_msat
+	};
+	nodes[0].node.send_payment(payment_hash, RecipientOnionFields::spontaneous_empty(),
+	PaymentId(payment_hash.0), route_params, Retry::Attempts(0)).unwrap();
+	check_added_monitors(&nodes[0], 1);
+	pass_along_route(&nodes[0], &[&[&nodes[1]]], amt_msat, payment_hash, payment_secret);
+	if success {
+ claim_payment(&nodes[0], &[&nodes[1]], payment_preimage);
+	} else {
+ fail_payment(&nodes[0], &[&nodes[1]], payment_hash);
+	}
+}
+
+#[test]
+fn mpp_to_one_hop_blinded_path() {
+	let chanmon_cfgs = create_chanmon_cfgs(4);
+	let node_cfgs = create_node_cfgs(4, &chanmon_cfgs);
+	let node_chanmgrs = create_node_chanmgrs(4, &node_cfgs, &[None, None, None, None]);
+	let nodes = create_network(4, &node_cfgs, &node_chanmgrs);
+	let mut secp_ctx = Secp256k1::new();
+
+	create_announced_chan_between_nodes(&nodes, 0, 1);
+	create_announced_chan_between_nodes(&nodes, 0, 2);
+	let chan_upd_1_3 = create_announced_chan_between_nodes(&nodes, 1, 3).0.contents;
+	create_announced_chan_between_nodes(&nodes, 2, 3).0.contents;
+
+	let amt_msat = 15_000_000;
+	let (payment_preimage, payment_hash, payment_secret) = get_payment_preimage_hash(&nodes[3], Some(amt_msat), None);
+	let payee_tlvs = ReceiveTlvs {
+ payment_secret,
+ payment_constraints: PaymentConstraints {
+ max_cltv_expiry: u32::max_value(),
+ htlc_minimum_msat: chan_upd_1_3.htlc_minimum_msat,
+ },
+	};
+	let blinded_path = BlindedPath::one_hop_for_payment(
+ nodes[3].node.get_our_node_id(), payee_tlvs, &chanmon_cfgs[3].keys_manager, &secp_ctx
+	).unwrap();
+
+	let bolt12_features: Bolt12InvoiceFeatures =
+ channelmanager::provided_invoice_features(&UserConfig::default()).to_context();
+	let route_params = RouteParameters {
+ payment_params: PaymentParameters::blinded(vec![blinded_path])
+ .with_bolt12_features(bolt12_features).unwrap(),
+ final_value_msat: amt_msat,
+	};
+	nodes[0].node.send_payment(payment_hash, RecipientOnionFields::spontaneous_empty(), PaymentId(payment_hash.0), route_params, Retry::Attempts(0)).unwrap();
+	check_added_monitors(&nodes[0], 2);
+
+	let expected_route: &[&[&Node]] = &[&[&nodes[1], &nodes[3]], &[&nodes[2], &nodes[3]]];
+	let mut events = nodes[0].node.get_and_clear_pending_msg_events();
+	assert_eq!(events.len(), 2);
+
+	let ev = remove_first_msg_event_to_node(&nodes[1].node.get_our_node_id(), &mut events);
+	pass_along_path(&nodes[0], expected_route[0], amt_msat, payment_hash.clone(),
+ Some(payment_secret), ev.clone(), false, None);
+
+	let ev = remove_first_msg_event_to_node(&nodes[2].node.get_our_node_id(), &mut events);
+	pass_along_path(&nodes[0], expected_route[1], amt_msat, payment_hash.clone(),
+ Some(payment_secret), ev.clone(), true, None);
+	claim_payment_along_route(&nodes[0], expected_route, false, payment_preimage);
+}

lightning/src/ln/channelmanager.rs

@@ -2738,7 +2738,7 @@ where
  let (short_channel_id, amt_to_forward, outgoing_cltv_value) = match hop_data {
  msgs::InboundOnionPayload::Forward { short_channel_id, amt_to_forward, outgoing_cltv_value } =>
  (short_channel_id, amt_to_forward, outgoing_cltv_value),
- msgs::InboundOnionPayload::Receive { .. } =>
+ msgs::InboundOnionPayload::Receive { .. } | msgs::InboundOnionPayload::BlindedReceive { .. } =>
  return Err(InboundOnionErr {
  msg: "Final Node OnionHopData provided for us as an intermediary node",
  err_code: 0x4000 | 22,
@@ -2770,12 +2770,19 @@ where
  payment_data, keysend_preimage, custom_tlvs, amt_msat, outgoing_cltv_value, payment_metadata, ..
  } =>
  (payment_data, keysend_preimage, custom_tlvs, amt_msat, outgoing_cltv_value, payment_metadata),
- _ =>
+ msgs::InboundOnionPayload::BlindedReceive {
+ amt_msat, total_msat, outgoing_cltv_value, payment_secret, ..
+ } => {
+ let payment_data = msgs::FinalOnionHopData { payment_secret, total_msat };
+ (Some(payment_data), None, Vec::new(), amt_msat, outgoing_cltv_value, None)
+ }
+ msgs::InboundOnionPayload::Forward { .. } => {
  return Err(InboundOnionErr {
  err_code: 0x4000|22,
  err_data: Vec::new(),
  msg: "Got non final data with an HMAC of 0",
- }),
+ })
+ },
  };
  // final_incorrect_cltv_expiry
  if outgoing_cltv_value > cltv_expiry {
@@ -2915,7 +2922,10 @@ where
  }
  }
 
- let next_hop = match onion_utils::decode_next_payment_hop(shared_secret, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac, msg.payment_hash) {
+ let next_hop = match onion_utils::decode_next_payment_hop(
+ shared_secret, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac,
+ msg.payment_hash, &self.node_signer
+ ) {
  Ok(res) => res,
  Err(onion_utils::OnionDecodeErr::Malformed { err_msg, err_code }) => {
  return_malformed_err!(err_msg, err_code);
@@ -2937,7 +2947,9 @@ where
  // We'll do receive checks in [`Self::construct_pending_htlc_info`] so we have access to the
  // inbound channel's state.
  onion_utils::Hop::Receive { .. } => return Ok((next_hop, shared_secret, None)),
- onion_utils::Hop::Forward { next_hop_data: msgs::InboundOnionPayload::Receive { .. }, .. } => {
+ onion_utils::Hop::Forward { next_hop_data: msgs::InboundOnionPayload::Receive { .. }, .. } |
+ onion_utils::Hop::Forward { next_hop_data: msgs::InboundOnionPayload::BlindedReceive { .. }, .. } =>
+ {
  return_err!("Final Node OnionHopData provided for us as an intermediary node", 0x4000 | 22, &[0; 0]);
  }
  };
@@ -3924,7 +3936,10 @@ where
  let phantom_pubkey_res = self.node_signer.get_node_id(Recipient::PhantomNode);
  if phantom_pubkey_res.is_ok() && fake_scid::is_valid_phantom(&self.fake_scid_rand_bytes, short_chan_id, &self.genesis_hash) {
  let phantom_shared_secret = self.node_signer.ecdh(Recipient::PhantomNode, &onion_packet.public_key.unwrap(), None).unwrap().secret_bytes();
- let next_hop = match onion_utils::decode_next_payment_hop(phantom_shared_secret, &onion_packet.hop_data, onion_packet.hmac, payment_hash) {
+ let next_hop = match onion_utils::decode_next_payment_hop(
+ phantom_shared_secret, &onion_packet.hop_data, onion_packet.hmac,
+ payment_hash, &self.node_signer
+ ) {
  Ok(res) => res,
  Err(onion_utils::OnionDecodeErr::Malformed { err_msg, err_code }) => {
  let sha256_of_onion = Sha256::hash(&onion_packet.hop_data).into_inner();

lightning/src/ln/mod.rs

@@ -43,6 +43,9 @@ pub mod wire;
 // without the node parameter being mut. This is incorrect, and thus newer rustcs will complain
 // about an unnecessary mut. Thus, we silence the unused_mut warning in two test modules below.
 
+#[cfg(test)]
+#[allow(unused_mut)]
+mod blinded_payment_tests;
 #[cfg(test)]
 #[allow(unused_mut)]
 mod functional_tests;

fuzz/src/onion_hop_data.rs

@@ -11,18 +11,21 @@
 // To modify it, modify msg_target_template.txt and run gen_target.sh instead.
 
 use crate::utils::test_logger;
+use lightning::util::test_utils;
 
 #[inline]
 pub fn onion_hop_data_test<Out: test_logger::Output>(data: &[u8], _out: Out) {
-	use lightning::util::ser::Readable;
+	use lightning::util::ser::ReadableArgs;
 	let mut r = ::std::io::Cursor::new(data);
-	let _ = <lightning::ln::msgs::InboundOnionPayload as Readable>::read(&mut r);
+	let node_signer = test_utils::TestNodeSigner::new(test_utils::privkey(42));
+	let _ = <lightning::ln::msgs::InboundOnionPayload as ReadableArgs<&&test_utils::TestNodeSigner>>::read(&mut r, &&node_signer);
 }
 
 #[no_mangle]
 pub extern "C" fn onion_hop_data_run(data: *const u8, datalen: usize) {
-	use lightning::util::ser::Readable;
+	use lightning::util::ser::ReadableArgs;
 	let data = unsafe { std::slice::from_raw_parts(data, datalen) };
 	let mut r = ::std::io::Cursor::new(data);
-	let _ = <lightning::ln::msgs::InboundOnionPayload as Readable>::read(&mut r);
+	let node_signer = test_utils::TestNodeSigner::new(test_utils::privkey(42));
+	let _ = <lightning::ln::msgs::InboundOnionPayload as ReadableArgs<&&test_utils::TestNodeSigner>>::read(&mut r, &&node_signer);
 }

lightning/src/blinded_path/mod.rs

@@ -76,6 +76,19 @@ impl BlindedPath {
  })
 	}
 
+	/// Create a one-hop blinded path for a payment.
+	pub fn one_hop_for_payment<ES: EntropySource, T: secp256k1::Signing + secp256k1::Verification>(
+ payee_node_id: PublicKey, payee_tlvs: payment::ReceiveTlvs, entropy_source: &ES,
+ secp_ctx: &Secp256k1<T>
+	) -> Result<(BlindedPayInfo, Self), ()> {
+ // This value is not considered in pathfinding for 1-hop blinded paths, because it's intended to
+ // be in relation to a specific channel.
+ let htlc_maximum_msat = u64::max_value();
+ Self::new_for_payment(
+ &[], payee_node_id, payee_tlvs, htlc_maximum_msat, entropy_source, secp_ctx
+ )
+	}
+
 	/// Create a blinded path for a payment, to be forwarded along `intermediate_nodes`.
 	///
 	/// Errors if:
@@ -85,7 +98,7 @@ impl BlindedPath {
 	///
 	/// [`ForwardTlvs`]: crate::blinded_path::payment::ForwardTlvs
 	// TODO: make all payloads the same size with padding + add dummy hops
-	pub fn new_for_payment<ES: EntropySource, T: secp256k1::Signing + secp256k1::Verification>(
+	pub(crate) fn new_for_payment<ES: EntropySource, T: secp256k1::Signing + secp256k1::Verification>(
  intermediate_nodes: &[payment::ForwardNode], payee_node_id: PublicKey,
  payee_tlvs: payment::ReceiveTlvs, htlc_maximum_msat: u64, entropy_source: &ES,
  secp_ctx: &Secp256k1<T>

lightning/src/blinded_path/payment.rs

@@ -119,6 +119,21 @@ impl Writeable for ReceiveTlvs {
 	}
 }
 
+// This will be removed once we support forwarding blinded HTLCs, because we'll always read a
+// `BlindedPaymentTlvs` instead.
+impl Readable for ReceiveTlvs {
+	fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
+ _init_and_read_tlv_stream!(r, {
+ (12, payment_constraints, required),
+ (65536, payment_secret, required),
+ });
+ Ok(Self {
+ payment_secret: payment_secret.0.unwrap(),
+ payment_constraints: payment_constraints.0.unwrap()
+ })
+	}
+}
+
 impl<'a> Writeable for BlindedPaymentTlvsRef<'a> {
 	fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
  // TODO: write padding

lightning/src/ln/blinded_payment_tests.rs

@@ -0,0 +1,113 @@
+// This file is Copyright its original authors, visible in version control
+// history.
+//
+// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
+// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
+// You may not use this file except in accordance with one or both of these
+// licenses.
+
+use bitcoin::secp256k1::Secp256k1;
+use crate::blinded_path::BlindedPath;
+use crate::blinded_path::payment::{PaymentConstraints, ReceiveTlvs};
+use crate::events::MessageSendEventsProvider;
+use crate::ln::channelmanager;
+use crate::ln::channelmanager::{PaymentId, RecipientOnionFields};
+use crate::ln::features::Bolt12InvoiceFeatures;
+use crate::ln::functional_test_utils::*;
+use crate::ln::outbound_payment::Retry;
+use crate::prelude::*;
+use crate::routing::router::{PaymentParameters, RouteParameters};
+use crate::util::config::UserConfig;
+
+#[test]
+fn one_hop_blinded_path() {
+	do_one_hop_blinded_path(true);
+	do_one_hop_blinded_path(false);
+}
+
+fn do_one_hop_blinded_path(success: bool) {
+	let chanmon_cfgs = create_chanmon_cfgs(2);
+	let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
+	let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
+	let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
+	let chan_upd = create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0).0.contents;
+
+	let amt_msat = 5000;
+	let (payment_preimage, payment_hash, payment_secret) = get_payment_preimage_hash(&nodes[1], Some(amt_msat), None);
+	let payee_tlvs = ReceiveTlvs {
+ payment_secret,
+ payment_constraints: PaymentConstraints {
+ max_cltv_expiry: u32::max_value(),
+ htlc_minimum_msat: chan_upd.htlc_minimum_msat,
+ },
+	};
+	let mut secp_ctx = Secp256k1::new();
+	let blinded_path = BlindedPath::one_hop_for_payment(
+ nodes[1].node.get_our_node_id(), payee_tlvs, &chanmon_cfgs[1].keys_manager, &secp_ctx
+	).unwrap();
+
+	let route_params = RouteParameters {
+ payment_params: PaymentParameters::blinded(vec![blinded_path]),
+ final_value_msat: amt_msat
+	};
+	nodes[0].node.send_payment(payment_hash, RecipientOnionFields::spontaneous_empty(),
+	PaymentId(payment_hash.0), route_params, Retry::Attempts(0)).unwrap();
+	check_added_monitors(&nodes[0], 1);
+	pass_along_route(&nodes[0], &[&[&nodes[1]]], amt_msat, payment_hash, payment_secret);
+	if success {
+ claim_payment(&nodes[0], &[&nodes[1]], payment_preimage);
+	} else {
+ fail_payment(&nodes[0], &[&nodes[1]], payment_hash);
+	}
+}
+
+#[test]
+fn mpp_to_one_hop_blinded_path() {
+	let chanmon_cfgs = create_chanmon_cfgs(4);
+	let node_cfgs = create_node_cfgs(4, &chanmon_cfgs);
+	let node_chanmgrs = create_node_chanmgrs(4, &node_cfgs, &[None, None, None, None]);
+	let nodes = create_network(4, &node_cfgs, &node_chanmgrs);
+	let mut secp_ctx = Secp256k1::new();
+
+	create_announced_chan_between_nodes(&nodes, 0, 1);
+	create_announced_chan_between_nodes(&nodes, 0, 2);
+	let chan_upd_1_3 = create_announced_chan_between_nodes(&nodes, 1, 3).0.contents;
+	create_announced_chan_between_nodes(&nodes, 2, 3).0.contents;
+
+	let amt_msat = 15_000_000;
+	let (payment_preimage, payment_hash, payment_secret) = get_payment_preimage_hash(&nodes[3], Some(amt_msat), None);
+	let payee_tlvs = ReceiveTlvs {
+ payment_secret,
+ payment_constraints: PaymentConstraints {
+ max_cltv_expiry: u32::max_value(),
+ htlc_minimum_msat: chan_upd_1_3.htlc_minimum_msat,
+ },
+	};
+	let blinded_path = BlindedPath::one_hop_for_payment(
+ nodes[3].node.get_our_node_id(), payee_tlvs, &chanmon_cfgs[3].keys_manager, &secp_ctx
+	).unwrap();
+
+	let bolt12_features: Bolt12InvoiceFeatures =
+ channelmanager::provided_invoice_features(&UserConfig::default()).to_context();
+	let route_params = RouteParameters {
+ payment_params: PaymentParameters::blinded(vec![blinded_path])
+ .with_bolt12_features(bolt12_features).unwrap(),
+ final_value_msat: amt_msat,
+	};
+	nodes[0].node.send_payment(payment_hash, RecipientOnionFields::spontaneous_empty(), PaymentId(payment_hash.0), route_params, Retry::Attempts(0)).unwrap();
+	check_added_monitors(&nodes[0], 2);
+
+	let expected_route: &[&[&Node]] = &[&[&nodes[1], &nodes[3]], &[&nodes[2], &nodes[3]]];
+	let mut events = nodes[0].node.get_and_clear_pending_msg_events();
+	assert_eq!(events.len(), 2);
+
+	let ev = remove_first_msg_event_to_node(&nodes[1].node.get_our_node_id(), &mut events);
+	pass_along_path(&nodes[0], expected_route[0], amt_msat, payment_hash.clone(),
+ Some(payment_secret), ev.clone(), false, None);
+
+	let ev = remove_first_msg_event_to_node(&nodes[2].node.get_our_node_id(), &mut events);
+	pass_along_path(&nodes[0], expected_route[1], amt_msat, payment_hash.clone(),
+ Some(payment_secret), ev.clone(), true, None);
+	claim_payment_along_route(&nodes[0], expected_route, false, payment_preimage);
+}

lightning/src/ln/channelmanager.rs

@@ -2738,7 +2738,7 @@ where
  let (short_channel_id, amt_to_forward, outgoing_cltv_value) = match hop_data {
  msgs::InboundOnionPayload::Forward { short_channel_id, amt_to_forward, outgoing_cltv_value } =>
  (short_channel_id, amt_to_forward, outgoing_cltv_value),
- msgs::InboundOnionPayload::Receive { .. } =>
+ msgs::InboundOnionPayload::Receive { .. } | msgs::InboundOnionPayload::BlindedReceive { .. } =>
  return Err(InboundOnionErr {
  msg: "Final Node OnionHopData provided for us as an intermediary node",
  err_code: 0x4000 | 22,
@@ -2770,12 +2770,19 @@ where
  payment_data, keysend_preimage, custom_tlvs, amt_msat, outgoing_cltv_value, payment_metadata, ..
  } =>
  (payment_data, keysend_preimage, custom_tlvs, amt_msat, outgoing_cltv_value, payment_metadata),
- _ =>
+ msgs::InboundOnionPayload::BlindedReceive {
+ amt_msat, total_msat, outgoing_cltv_value, payment_secret, ..
+ } => {
+ let payment_data = msgs::FinalOnionHopData { payment_secret, total_msat };
+ (Some(payment_data), None, Vec::new(), amt_msat, outgoing_cltv_value, None)
+ }
+ msgs::InboundOnionPayload::Forward { .. } => {
  return Err(InboundOnionErr {
  err_code: 0x4000|22,
  err_data: Vec::new(),
  msg: "Got non final data with an HMAC of 0",
- }),
+ })
+ },
  };
  // final_incorrect_cltv_expiry
  if outgoing_cltv_value > cltv_expiry {
@@ -2915,7 +2922,10 @@ where
  }
  }
 
- let next_hop = match onion_utils::decode_next_payment_hop(shared_secret, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac, msg.payment_hash) {
+ let next_hop = match onion_utils::decode_next_payment_hop(
+ shared_secret, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac,
+ msg.payment_hash, &self.node_signer
+ ) {
  Ok(res) => res,
  Err(onion_utils::OnionDecodeErr::Malformed { err_msg, err_code }) => {
  return_malformed_err!(err_msg, err_code);
@@ -2937,7 +2947,9 @@ where
  // We'll do receive checks in [`Self::construct_pending_htlc_info`] so we have access to the
  // inbound channel's state.
  onion_utils::Hop::Receive { .. } => return Ok((next_hop, shared_secret, None)),
- onion_utils::Hop::Forward { next_hop_data: msgs::InboundOnionPayload::Receive { .. }, .. } => {
+ onion_utils::Hop::Forward { next_hop_data: msgs::InboundOnionPayload::Receive { .. }, .. } |
+ onion_utils::Hop::Forward { next_hop_data: msgs::InboundOnionPayload::BlindedReceive { .. }, .. } =>
+ {
  return_err!("Final Node OnionHopData provided for us as an intermediary node", 0x4000 | 22, &[0; 0]);
  }
  };
@@ -3924,7 +3936,10 @@ where
  let phantom_pubkey_res = self.node_signer.get_node_id(Recipient::PhantomNode);
  if phantom_pubkey_res.is_ok() && fake_scid::is_valid_phantom(&self.fake_scid_rand_bytes, short_chan_id, &self.genesis_hash) {
  let phantom_shared_secret = self.node_signer.ecdh(Recipient::PhantomNode, &onion_packet.public_key.unwrap(), None).unwrap().secret_bytes();
- let next_hop = match onion_utils::decode_next_payment_hop(phantom_shared_secret, &onion_packet.hop_data, onion_packet.hmac, payment_hash) {
+ let next_hop = match onion_utils::decode_next_payment_hop(
+ phantom_shared_secret, &onion_packet.hop_data, onion_packet.hmac,
+ payment_hash, &self.node_signer
+ ) {
  Ok(res) => res,
  Err(onion_utils::OnionDecodeErr::Malformed { err_msg, err_code }) => {
  let sha256_of_onion = Sha256::hash(&onion_packet.hop_data).into_inner();

lightning/src/ln/mod.rs

@@ -43,6 +43,9 @@ pub mod wire;
 // without the node parameter being mut. This is incorrect, and thus newer rustcs will complain
 // about an unnecessary mut. Thus, we silence the unused_mut warning in two test modules below.
 
+#[cfg(test)]
+#[allow(unused_mut)]
+mod blinded_payment_tests;
 #[cfg(test)]
 #[allow(unused_mut)]
 mod functional_tests;

fuzz/src/onion_hop_data.rs

@@ -11,18 +11,21 @@
 // To modify it, modify msg_target_template.txt and run gen_target.sh instead.
 
 use crate::utils::test_logger;
+use lightning::util::test_utils;
 
 #[inline]
 pub fn onion_hop_data_test<Out: test_logger::Output>(data: &[u8], _out: Out) {
-	use lightning::util::ser::Readable;
+	use lightning::util::ser::ReadableArgs;
 	let mut r = ::std::io::Cursor::new(data);
-	let _ = <lightning::ln::msgs::InboundOnionPayload as Readable>::read(&mut r);
+	let node_signer = test_utils::TestNodeSigner::new(test_utils::privkey(42));
+	let _ = <lightning::ln::msgs::InboundOnionPayload as ReadableArgs<&&test_utils::TestNodeSigner>>::read(&mut r, &&node_signer);
 }
 
 #[no_mangle]
 pub extern "C" fn onion_hop_data_run(data: *const u8, datalen: usize) {
-	use lightning::util::ser::Readable;
+	use lightning::util::ser::ReadableArgs;
 	let data = unsafe { std::slice::from_raw_parts(data, datalen) };
 	let mut r = ::std::io::Cursor::new(data);
-	let _ = <lightning::ln::msgs::InboundOnionPayload as Readable>::read(&mut r);
+	let node_signer = test_utils::TestNodeSigner::new(test_utils::privkey(42));
+	let _ = <lightning::ln::msgs::InboundOnionPayload as ReadableArgs<&&test_utils::TestNodeSigner>>::read(&mut r, &&node_signer);
 }

lightning/src/blinded_path/mod.rs

@@ -76,6 +76,19 @@ impl BlindedPath {
  })
 	}
 
+	/// Create a one-hop blinded path for a payment.
+	pub fn one_hop_for_payment<ES: EntropySource, T: secp256k1::Signing + secp256k1::Verification>(
+ payee_node_id: PublicKey, payee_tlvs: payment::ReceiveTlvs, entropy_source: &ES,
+ secp_ctx: &Secp256k1<T>
+	) -> Result<(BlindedPayInfo, Self), ()> {
+ // This value is not considered in pathfinding for 1-hop blinded paths, because it's intended to
+ // be in relation to a specific channel.
+ let htlc_maximum_msat = u64::max_value();
+ Self::new_for_payment(
+ &[], payee_node_id, payee_tlvs, htlc_maximum_msat, entropy_source, secp_ctx
+ )
+	}
+
 	/// Create a blinded path for a payment, to be forwarded along `intermediate_nodes`.
 	///
 	/// Errors if:
@@ -85,7 +98,7 @@ impl BlindedPath {
 	///
 	/// [`ForwardTlvs`]: crate::blinded_path::payment::ForwardTlvs
 	// TODO: make all payloads the same size with padding + add dummy hops
-	pub fn new_for_payment<ES: EntropySource, T: secp256k1::Signing + secp256k1::Verification>(
+	pub(crate) fn new_for_payment<ES: EntropySource, T: secp256k1::Signing + secp256k1::Verification>(
  intermediate_nodes: &[payment::ForwardNode], payee_node_id: PublicKey,
  payee_tlvs: payment::ReceiveTlvs, htlc_maximum_msat: u64, entropy_source: &ES,
  secp_ctx: &Secp256k1<T>

lightning/src/blinded_path/payment.rs

@@ -119,6 +119,21 @@ impl Writeable for ReceiveTlvs {
 	}
 }
 
+// This will be removed once we support forwarding blinded HTLCs, because we'll always read a
+// `BlindedPaymentTlvs` instead.
+impl Readable for ReceiveTlvs {
+	fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
+ _init_and_read_tlv_stream!(r, {
+ (12, payment_constraints, required),
+ (65536, payment_secret, required),
+ });
+ Ok(Self {
+ payment_secret: payment_secret.0.unwrap(),
+ payment_constraints: payment_constraints.0.unwrap()
+ })
+	}
+}
+
 impl<'a> Writeable for BlindedPaymentTlvsRef<'a> {
 	fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
  // TODO: write padding

lightning/src/ln/blinded_payment_tests.rs

@@ -0,0 +1,113 @@
+// This file is Copyright its original authors, visible in version control
+// history.
+//
+// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
+// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
+// You may not use this file except in accordance with one or both of these
+// licenses.
+
+use bitcoin::secp256k1::Secp256k1;
+use crate::blinded_path::BlindedPath;
+use crate::blinded_path::payment::{PaymentConstraints, ReceiveTlvs};
+use crate::events::MessageSendEventsProvider;
+use crate::ln::channelmanager;
+use crate::ln::channelmanager::{PaymentId, RecipientOnionFields};
+use crate::ln::features::Bolt12InvoiceFeatures;
+use crate::ln::functional_test_utils::*;
+use crate::ln::outbound_payment::Retry;
+use crate::prelude::*;
+use crate::routing::router::{PaymentParameters, RouteParameters};
+use crate::util::config::UserConfig;
+
+#[test]
+fn one_hop_blinded_path() {
+	do_one_hop_blinded_path(true);
+	do_one_hop_blinded_path(false);
+}
+
+fn do_one_hop_blinded_path(success: bool) {
+	let chanmon_cfgs = create_chanmon_cfgs(2);
+	let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
+	let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
+	let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
+	let chan_upd = create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0).0.contents;
+
+	let amt_msat = 5000;
+	let (payment_preimage, payment_hash, payment_secret) = get_payment_preimage_hash(&nodes[1], Some(amt_msat), None);
+	let payee_tlvs = ReceiveTlvs {
+ payment_secret,
+ payment_constraints: PaymentConstraints {
+ max_cltv_expiry: u32::max_value(),
+ htlc_minimum_msat: chan_upd.htlc_minimum_msat,
+ },
+	};
+	let mut secp_ctx = Secp256k1::new();
+	let blinded_path = BlindedPath::one_hop_for_payment(
+ nodes[1].node.get_our_node_id(), payee_tlvs, &chanmon_cfgs[1].keys_manager, &secp_ctx
+	).unwrap();
+
+	let route_params = RouteParameters {
+ payment_params: PaymentParameters::blinded(vec![blinded_path]),
+ final_value_msat: amt_msat
+	};
+	nodes[0].node.send_payment(payment_hash, RecipientOnionFields::spontaneous_empty(),
+	PaymentId(payment_hash.0), route_params, Retry::Attempts(0)).unwrap();
+	check_added_monitors(&nodes[0], 1);
+	pass_along_route(&nodes[0], &[&[&nodes[1]]], amt_msat, payment_hash, payment_secret);
+	if success {
+ claim_payment(&nodes[0], &[&nodes[1]], payment_preimage);
+	} else {
+ fail_payment(&nodes[0], &[&nodes[1]], payment_hash);
+	}
+}
+
+#[test]
+fn mpp_to_one_hop_blinded_path() {
+	let chanmon_cfgs = create_chanmon_cfgs(4);
+	let node_cfgs = create_node_cfgs(4, &chanmon_cfgs);
+	let node_chanmgrs = create_node_chanmgrs(4, &node_cfgs, &[None, None, None, None]);
+	let nodes = create_network(4, &node_cfgs, &node_chanmgrs);
+	let mut secp_ctx = Secp256k1::new();
+
+	create_announced_chan_between_nodes(&nodes, 0, 1);
+	create_announced_chan_between_nodes(&nodes, 0, 2);
+	let chan_upd_1_3 = create_announced_chan_between_nodes(&nodes, 1, 3).0.contents;
+	create_announced_chan_between_nodes(&nodes, 2, 3).0.contents;
+
+	let amt_msat = 15_000_000;
+	let (payment_preimage, payment_hash, payment_secret) = get_payment_preimage_hash(&nodes[3], Some(amt_msat), None);
+	let payee_tlvs = ReceiveTlvs {
+ payment_secret,
+ payment_constraints: PaymentConstraints {
+ max_cltv_expiry: u32::max_value(),
+ htlc_minimum_msat: chan_upd_1_3.htlc_minimum_msat,
+ },
+	};
+	let blinded_path = BlindedPath::one_hop_for_payment(
+ nodes[3].node.get_our_node_id(), payee_tlvs, &chanmon_cfgs[3].keys_manager, &secp_ctx
+	).unwrap();
+
+	let bolt12_features: Bolt12InvoiceFeatures =
+ channelmanager::provided_invoice_features(&UserConfig::default()).to_context();
+	let route_params = RouteParameters {
+ payment_params: PaymentParameters::blinded(vec![blinded_path])
+ .with_bolt12_features(bolt12_features).unwrap(),
+ final_value_msat: amt_msat,
+	};
+	nodes[0].node.send_payment(payment_hash, RecipientOnionFields::spontaneous_empty(), PaymentId(payment_hash.0), route_params, Retry::Attempts(0)).unwrap();
+	check_added_monitors(&nodes[0], 2);
+
+	let expected_route: &[&[&Node]] = &[&[&nodes[1], &nodes[3]], &[&nodes[2], &nodes[3]]];
+	let mut events = nodes[0].node.get_and_clear_pending_msg_events();
+	assert_eq!(events.len(), 2);
+
+	let ev = remove_first_msg_event_to_node(&nodes[1].node.get_our_node_id(), &mut events);
+	pass_along_path(&nodes[0], expected_route[0], amt_msat, payment_hash.clone(),
+ Some(payment_secret), ev.clone(), false, None);
+
+	let ev = remove_first_msg_event_to_node(&nodes[2].node.get_our_node_id(), &mut events);
+	pass_along_path(&nodes[0], expected_route[1], amt_msat, payment_hash.clone(),
+ Some(payment_secret), ev.clone(), true, None);
+	claim_payment_along_route(&nodes[0], expected_route, false, payment_preimage);
+}

lightning/src/ln/channelmanager.rs

@@ -2738,7 +2738,7 @@ where
  let (short_channel_id, amt_to_forward, outgoing_cltv_value) = match hop_data {
  msgs::InboundOnionPayload::Forward { short_channel_id, amt_to_forward, outgoing_cltv_value } =>
  (short_channel_id, amt_to_forward, outgoing_cltv_value),
- msgs::InboundOnionPayload::Receive { .. } =>
+ msgs::InboundOnionPayload::Receive { .. } | msgs::InboundOnionPayload::BlindedReceive { .. } =>
  return Err(InboundOnionErr {
  msg: "Final Node OnionHopData provided for us as an intermediary node",
  err_code: 0x4000 | 22,
@@ -2770,12 +2770,19 @@ where
  payment_data, keysend_preimage, custom_tlvs, amt_msat, outgoing_cltv_value, payment_metadata, ..
  } =>
  (payment_data, keysend_preimage, custom_tlvs, amt_msat, outgoing_cltv_value, payment_metadata),
- _ =>
+ msgs::InboundOnionPayload::BlindedReceive {
+ amt_msat, total_msat, outgoing_cltv_value, payment_secret, ..
+ } => {
+ let payment_data = msgs::FinalOnionHopData { payment_secret, total_msat };
+ (Some(payment_data), None, Vec::new(), amt_msat, outgoing_cltv_value, None)
+ }
+ msgs::InboundOnionPayload::Forward { .. } => {
  return Err(InboundOnionErr {
  err_code: 0x4000|22,
  err_data: Vec::new(),
  msg: "Got non final data with an HMAC of 0",
- }),
+ })
+ },
  };
  // final_incorrect_cltv_expiry
  if outgoing_cltv_value > cltv_expiry {
@@ -2915,7 +2922,10 @@ where
  }
  }
 
- let next_hop = match onion_utils::decode_next_payment_hop(shared_secret, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac, msg.payment_hash) {
+ let next_hop = match onion_utils::decode_next_payment_hop(
+ shared_secret, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac,
+ msg.payment_hash, &self.node_signer
+ ) {
  Ok(res) => res,
  Err(onion_utils::OnionDecodeErr::Malformed { err_msg, err_code }) => {
  return_malformed_err!(err_msg, err_code);
@@ -2937,7 +2947,9 @@ where
  // We'll do receive checks in [`Self::construct_pending_htlc_info`] so we have access to the
  // inbound channel's state.
  onion_utils::Hop::Receive { .. } => return Ok((next_hop, shared_secret, None)),
- onion_utils::Hop::Forward { next_hop_data: msgs::InboundOnionPayload::Receive { .. }, .. } => {
+ onion_utils::Hop::Forward { next_hop_data: msgs::InboundOnionPayload::Receive { .. }, .. } |
+ onion_utils::Hop::Forward { next_hop_data: msgs::InboundOnionPayload::BlindedReceive { .. }, .. } =>
+ {
  return_err!("Final Node OnionHopData provided for us as an intermediary node", 0x4000 | 22, &[0; 0]);
  }
  };
@@ -3924,7 +3936,10 @@ where
  let phantom_pubkey_res = self.node_signer.get_node_id(Recipient::PhantomNode);
  if phantom_pubkey_res.is_ok() && fake_scid::is_valid_phantom(&self.fake_scid_rand_bytes, short_chan_id, &self.genesis_hash) {
  let phantom_shared_secret = self.node_signer.ecdh(Recipient::PhantomNode, &onion_packet.public_key.unwrap(), None).unwrap().secret_bytes();
- let next_hop = match onion_utils::decode_next_payment_hop(phantom_shared_secret, &onion_packet.hop_data, onion_packet.hmac, payment_hash) {
+ let next_hop = match onion_utils::decode_next_payment_hop(
+ phantom_shared_secret, &onion_packet.hop_data, onion_packet.hmac,
+ payment_hash, &self.node_signer
+ ) {
  Ok(res) => res,
  Err(onion_utils::OnionDecodeErr::Malformed { err_msg, err_code }) => {
  let sha256_of_onion = Sha256::hash(&onion_packet.hop_data).into_inner();

lightning/src/ln/mod.rs

@@ -43,6 +43,9 @@ pub mod wire;
 // without the node parameter being mut. This is incorrect, and thus newer rustcs will complain
 // about an unnecessary mut. Thus, we silence the unused_mut warning in two test modules below.
 
+#[cfg(test)]
+#[allow(unused_mut)]
+mod blinded_payment_tests;
 #[cfg(test)]
 #[allow(unused_mut)]
 mod functional_tests;