Support paying blinded paths

Completes single-path sending support. MPP support will be added later.

Author: valentinewallace

lightning/src/ln/channel.rs

@@ -3124,10 +3124,11 @@ impl<SP: Deref> Channel<SP> where
 				match &htlc_update {
 					&HTLCUpdateAwaitingACK::AddHTLC {
 						amount_msat, cltv_expiry, ref payment_hash, ref source, ref onion_routing_packet,
-						skimmed_fee_msat, ..
+						skimmed_fee_msat, blinding_point, ..
 					} => {
 						match self.send_htlc(amount_msat, *payment_hash, cltv_expiry, source.clone(),
-							onion_routing_packet.clone(), false, skimmed_fee_msat, fee_estimator, logger)
+							onion_routing_packet.clone(), false, skimmed_fee_msat, blinding_point, fee_estimator,
+							logger)
 						{
 							Ok(_) => update_add_count += 1,
 							Err(e) => {
@@ -3804,7 +3805,7 @@ impl<SP: Deref> Channel<SP> where
 					cltv_expiry: htlc.cltv_expiry,
 					onion_routing_packet: (**onion_packet).clone(),
 					skimmed_fee_msat: htlc.skimmed_fee_msat,
-					blinding_point: None,
+					blinding_point: htlc.blinding_point,
 				});
 			}
 		}
@@ -5150,13 +5151,11 @@ impl<SP: Deref> Channel<SP> where
 	pub fn queue_add_htlc<F: Deref, L: Deref>(
 		&mut self, amount_msat: u64, payment_hash: PaymentHash, cltv_expiry: u32, source: HTLCSource,
 		onion_routing_packet: msgs::OnionPacket, skimmed_fee_msat: Option<u64>,
-		fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &L
-	) -> Result<(), ChannelError>
-	where F::Target: FeeEstimator, L::Target: Logger
-	{
+		blinding_point: Option<PublicKey>, fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &L
+	) -> Result<(), ChannelError> where F::Target: FeeEstimator, L::Target: Logger {
 		self
 			.send_htlc(amount_msat, payment_hash, cltv_expiry, source, onion_routing_packet, true,
-				skimmed_fee_msat, fee_estimator, logger)
+				skimmed_fee_msat, blinding_point, fee_estimator, logger)
 			.map(|msg_opt| assert!(msg_opt.is_none(), "We forced holding cell?"))
 			.map_err(|err| {
 				if let ChannelError::Ignore(_) = err { /* fine */ }
@@ -5184,7 +5183,8 @@ impl<SP: Deref> Channel<SP> where
 	fn send_htlc<F: Deref, L: Deref>(
 		&mut self, amount_msat: u64, payment_hash: PaymentHash, cltv_expiry: u32, source: HTLCSource,
 		onion_routing_packet: msgs::OnionPacket, mut force_holding_cell: bool,
-		skimmed_fee_msat: Option<u64>, fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &L
+		skimmed_fee_msat: Option<u64>, blinding_point: Option<PublicKey>,
+		fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &L
 	) -> Result<Option<msgs::UpdateAddHTLC>, ChannelError>
 	where F::Target: FeeEstimator, L::Target: Logger
 	{
@@ -5241,7 +5241,7 @@ impl<SP: Deref> Channel<SP> where
 				source,
 				onion_routing_packet,
 				skimmed_fee_msat,
-				blinding_point: None,
+				blinding_point,
 			});
 			return Ok(None);
 		}
@@ -5253,7 +5253,7 @@ impl<SP: Deref> Channel<SP> where
 			cltv_expiry,
 			state: OutboundHTLCState::LocalAnnounced(Box::new(onion_routing_packet.clone())),
 			source,
-			blinding_point: None,
+			blinding_point,
 			skimmed_fee_msat,
 		});
 
@@ -5265,7 +5265,7 @@ impl<SP: Deref> Channel<SP> where
 			cltv_expiry,
 			onion_routing_packet,
 			skimmed_fee_msat,
-			blinding_point: None,
+			blinding_point,
 		};
 		self.context.next_holder_htlc_id += 1;
 
@@ -5420,12 +5420,12 @@ impl<SP: Deref> Channel<SP> where
 	pub fn send_htlc_and_commit<F: Deref, L: Deref>(
 		&mut self, amount_msat: u64, payment_hash: PaymentHash, cltv_expiry: u32,
 		source: HTLCSource, onion_routing_packet: msgs::OnionPacket, skimmed_fee_msat: Option<u64>,
-		fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &L
+		blinding_point: Option<PublicKey>, fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &L
 	) -> Result<Option<ChannelMonitorUpdate>, ChannelError>
 	where F::Target: FeeEstimator, L::Target: Logger
 	{
 		let send_res = self.send_htlc(amount_msat, payment_hash, cltv_expiry, source,
-			onion_routing_packet, false, skimmed_fee_msat, fee_estimator, logger);
+			onion_routing_packet, false, skimmed_fee_msat, blinding_point, fee_estimator, logger);
 		if let Err(e) = &send_res { if let ChannelError::Ignore(_) = e {} else { debug_assert!(false, "Sending cannot trigger channel failure"); } }
 		match send_res? {
 			Some(_) => {

lightning/src/ln/channelmanager.rs

@@ -3245,7 +3245,7 @@ where
 						session_priv: session_priv.clone(),
 						first_hop_htlc_msat: htlc_msat,
 						payment_id,
-					}, onion_packet, None, &self.fee_estimator, &self.logger);
+					}, onion_packet, None, None, &self.fee_estimator, &self.logger);
 				match break_chan_entry!(self, send_res, chan) {
 					Some(monitor_update) => {
 						match handle_new_monitor_update!(self, funding_txo, monitor_update, peer_state_lock, peer_state, per_peer_state, chan) {
@@ -3982,7 +3982,7 @@ where
 										});
 										if let Err(e) = chan.get_mut().queue_add_htlc(outgoing_amt_msat,
 											payment_hash, outgoing_cltv_value, htlc_source.clone(),
-											onion_packet, skimmed_fee_msat, &self.fee_estimator,
+											onion_packet, skimmed_fee_msat, None, &self.fee_estimator,
 											&self.logger)
 										{
 											if let ChannelError::Ignore(msg) = e {

lightning/src/ln/outbound_payment.rs

@@ -1075,10 +1075,6 @@ impl OutboundPayments {
 				path_errs.push(Err(APIError::InvalidRoute{err: "Path didn't go anywhere/had bogus size".to_owned()}));
 				continue 'path_check;
 			}
-			if path.blinded_tail.is_some() {
-				path_errs.push(Err(APIError::InvalidRoute{err: "Sending to blinded paths isn't supported yet".to_owned()}));
-				continue 'path_check;
-			}
 			let dest_hop_idx = if path.blinded_tail.is_some() && path.blinded_tail.as_ref().unwrap().hops.len() > 1 {
 				usize::max_value() } else { path.hops.len() - 1 };
 			for (idx, hop) in path.hops.iter().enumerate() {