Parse blinded forward-as-intro onion payloads

Previously, we only parsed blinded receive payloads.

Author: valentinewallace

lightning/src/ln/channelmanager.rs

@@ -53,7 +53,7 @@ use crate::routing::scoring::{ProbabilisticScorer, ProbabilisticScoringFeeParame
 use crate::ln::onion_payment::{check_incoming_htlc_cltv, create_recv_pending_htlc_info, create_fwd_pending_htlc_info, decode_incoming_update_add_htlc_onion, InboundOnionErr, NextPacketDetails};
 use crate::ln::msgs;
 use crate::ln::onion_utils;
-use crate::ln::onion_utils::{HTLCFailReason, INVALID_ONION_BLINDING};
+use crate::ln::onion_utils::HTLCFailReason;
 use crate::ln::msgs::{ChannelMessageHandler, DecodeError, LightningError};
 #[cfg(test)]
 use crate::ln::outbound_payment;

lightning/src/ln/msgs.rs

@@ -31,7 +31,7 @@ use bitcoin::{secp256k1, Witness};
 use bitcoin::blockdata::script::ScriptBuf;
 use bitcoin::hash_types::Txid;
 
-use crate::blinded_path::payment::ReceiveTlvs;
+use crate::blinded_path::payment::{BlindedPaymentTlvs, ForwardTlvs, ReceiveTlvs};
 use crate::ln::{ChannelId, PaymentPreimage, PaymentHash, PaymentSecret};
 use crate::ln::features::{ChannelFeatures, ChannelTypeFeatures, InitFeatures, NodeFeatures};
 use crate::ln::onion_utils;
@@ -1666,9 +1666,10 @@ pub trait OnionMessageHandler {
 
 mod fuzzy_internal_msgs {
 	use bitcoin::secp256k1::PublicKey;
-	use crate::blinded_path::payment::PaymentConstraints;
+	use crate::blinded_path::payment::{PaymentConstraints, PaymentRelay};
 	use crate::prelude::*;
 	use crate::ln::{PaymentPreimage, PaymentSecret};
+	use crate::ln::features::BlindedHopFeatures;
 
 	// These types aren't intended to be pub, but are exposed for direct fuzzing (as we deserialize
 	// them from untrusted input):
@@ -1695,6 +1696,13 @@ mod fuzzy_internal_msgs {
 			amt_msat: u64,
 			outgoing_cltv_value: u32,
 		},
+		BlindedForward {
+			short_channel_id: u64,
+			payment_relay: PaymentRelay,
+			payment_constraints: PaymentConstraints,
+			features: BlindedHopFeatures,
+			intro_node_blinding_point: PublicKey,
+		},
 		BlindedReceive {
 			amt_msat: u64,
 			total_msat: u64,
@@ -2354,7 +2362,23 @@ impl<NS: Deref> ReadableArgs<&NS> for InboundOnionPayload where NS::Target: Node
 			let mut s = Cursor::new(&enc_tlvs);
 			let mut reader = FixedLengthReader::new(&mut s, enc_tlvs.len() as u64);
 			match ChaChaPolyReadAdapter::read(&mut reader, rho)? {
-				ChaChaPolyReadAdapter { readable: ReceiveTlvs { payment_secret, payment_constraints }} => {
+				ChaChaPolyReadAdapter { readable: BlindedPaymentTlvs::Forward(ForwardTlvs {
+					short_channel_id, payment_relay, payment_constraints, features
+				})} => {
+					if amt.is_some() || cltv_value.is_some() || total_msat.is_some() {
+						return Err(DecodeError::InvalidValue)
+					}
+					Ok(Self::BlindedForward {
+						short_channel_id,
+						payment_relay,
+						payment_constraints,
+						features,
+						intro_node_blinding_point: blinding_point,
+					})
+				},
+				ChaChaPolyReadAdapter { readable: BlindedPaymentTlvs::Receive(ReceiveTlvs {
+					payment_secret, payment_constraints
+				})} => {
 					if total_msat.unwrap_or(0) > MAX_VALUE_MSAT { return Err(DecodeError::InvalidValue) }
 					Ok(Self::BlindedReceive {
 						amt_msat: amt.ok_or(DecodeError::InvalidValue)?,

lightning/src/ln/onion_payment.rs

@@ -11,7 +11,7 @@ use crate::ln::PaymentHash;
 use crate::ln::channelmanager::{CLTV_FAR_FAR_AWAY, HTLCFailureMsg, MIN_CLTV_EXPIRY_DELTA, PendingHTLCInfo, PendingHTLCRouting};
 use crate::ln::msgs;
 use crate::ln::onion_utils;
-use crate::ln::onion_utils::HTLCFailReason;
+use crate::ln::onion_utils::{HTLCFailReason, INVALID_ONION_BLINDING};
 use crate::sign::{NodeSigner, Recipient};
 use crate::util::logger::Logger;
 
@@ -44,6 +44,7 @@ pub(super) fn create_fwd_pending_htlc_info(
 	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::BlindedForward { .. } => todo!(),
 		msgs::InboundOnionPayload::Receive { .. } | msgs::InboundOnionPayload::BlindedReceive { .. } =>
 			return Err(InboundOnionErr {
 				msg: "Final Node OnionHopData provided for us as an intermediary node",
@@ -90,6 +91,13 @@ pub(super) fn create_recv_pending_htlc_info(
 				msg: "Got non final data with an HMAC of 0",
 			})
 		},
+		msgs::InboundOnionPayload::BlindedForward { .. } => {
+			return Err(InboundOnionErr {
+				err_code: INVALID_ONION_BLINDING,
+				err_data: vec![0; 32],
+				msg: "Got blinded non final data with an HMAC of 0",
+			})
+		}
 	};
 	// final_incorrect_cltv_expiry
 	if outgoing_cltv_value > cltv_expiry {
@@ -327,6 +335,11 @@ where
 				outgoing_amt_msat: amt_to_forward, outgoing_cltv_value
 			}
 		},
+		onion_utils::Hop::Forward {
+			next_hop_data: msgs::InboundOnionPayload::BlindedForward { .. }, ..
+		} => {
+			todo!()
+		},
 		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::BlindedReceive { .. }, .. } =>