Merge pull request lightningdevkit#3595 from arik-so/arik/trampoline/inbound-prefactors

Prefactor for inbound Trampoline parsing/decryption

Author: TheBlueMatt

Cargo.toml

@@ -62,6 +62,7 @@ check-cfg = [
     "cfg(ldk_bench)",
     "cfg(ldk_test_vectors)",
     "cfg(taproot)",
+    "cfg(trampoline)",
     "cfg(require_route_graph_test)",
     "cfg(splicing)",
     "cfg(async_payments)",

ci/ci-tests.sh

@@ -131,6 +131,8 @@ RUSTFLAGS="--cfg=taproot" cargo test --verbose --color always -p lightning
 [ "$CI_MINIMIZE_DISK_USAGE" != "" ] && cargo clean
 RUSTFLAGS="--cfg=splicing" cargo test --verbose --color always -p lightning
 [ "$CI_MINIMIZE_DISK_USAGE" != "" ] && cargo clean
+RUSTFLAGS="--cfg=trampoline" cargo test --verbose --color always -p lightning
+[ "$CI_MINIMIZE_DISK_USAGE" != "" ] && cargo clean
 RUSTFLAGS="--cfg=async_payments" cargo test --verbose --color always -p lightning
 [ "$CI_MINIMIZE_DISK_USAGE" != "" ] && cargo clean
 RUSTFLAGS="--cfg=lsps1_service" cargo test --verbose --color always -p lightning-liquidity

lightning/src/ln/channelmanager.rs

@@ -55,6 +55,8 @@ use crate::ln::channel_state::ChannelDetails;
 use crate::types::features::{Bolt12InvoiceFeatures, ChannelFeatures, ChannelTypeFeatures, InitFeatures, NodeFeatures};
 #[cfg(any(feature = "_test_utils", test))]
 use crate::types::features::Bolt11InvoiceFeatures;
+#[cfg(trampoline)]
+use crate::routing::gossip::NodeId;
 use crate::routing::router::{BlindedTail, FixedRouter, InFlightHtlcs, Path, Payee, PaymentParameters, Route, RouteParameters, Router};
 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, InboundHTLCErr, NextPacketDetails};
 use crate::ln::msgs;
@@ -168,6 +170,24 @@ pub enum PendingHTLCRouting {
 		/// The absolute CLTV of the inbound HTLC
 		incoming_cltv_expiry: Option<u32>,
 	},
+	/// An HTLC which should be forwarded on to another Trampoline node.
+	#[cfg(trampoline)]
+	TrampolineForward {
+		/// The onion shared secret we build with the sender (or the preceding Trampoline node) used
+		/// to decrypt the onion.
+		///
+		/// This is later used to encrypt failure packets in the event that the HTLC is failed.
+		incoming_shared_secret: [u8; 32],
+		/// The onion which should be included in the forwarded HTLC, telling the next hop what to
+		/// do with the HTLC.
+		onion_packet: msgs::TrampolineOnionPacket,
+		/// The node ID of the Trampoline node which we need to route this HTLC to.
+		node_id: NodeId,
+		/// Set if this HTLC is being forwarded within a blinded path.
+		blinded: Option<BlindedForward>,
+		/// The absolute CLTV of the inbound HTLC
+		incoming_cltv_expiry: u32,
+	},
 	/// The onion indicates that this is a payment for an invoice (supposedly) generated by us.
 	///
 	/// Note that at this point, we have not checked that the invoice being paid was actually
@@ -269,6 +289,8 @@ impl PendingHTLCRouting {
 	fn blinded_failure(&self) -> Option<BlindedFailure> {
 		match self {
 			Self::Forward { blinded: Some(BlindedForward { failure, .. }), .. } => Some(*failure),
+			#[cfg(trampoline)]
+			Self::TrampolineForward { blinded: Some(BlindedForward { failure, .. }), .. } => Some(*failure),
 			Self::Receive { requires_blinded_error: true, .. } => Some(BlindedFailure::FromBlindedNode),
 			Self::ReceiveKeysend { requires_blinded_error: true, .. } => Some(BlindedFailure::FromBlindedNode),
 			_ => None,
@@ -278,6 +300,8 @@ impl PendingHTLCRouting {
 	fn incoming_cltv_expiry(&self) -> Option<u32> {
 		match self {
 			Self::Forward { incoming_cltv_expiry, .. } => *incoming_cltv_expiry,
+			#[cfg(trampoline)]
+			Self::TrampolineForward { incoming_cltv_expiry, .. } => Some(*incoming_cltv_expiry),
 			Self::Receive { incoming_cltv_expiry, .. } => Some(*incoming_cltv_expiry),
 			Self::ReceiveKeysend { incoming_cltv_expiry, .. } => Some(*incoming_cltv_expiry),
 		}
@@ -8908,6 +8932,8 @@ This indicates a bug inside LDK. Please report this error at https://github.com/
 				for (forward_info, prev_htlc_id) in pending_forwards.drain(..) {
 					let scid = match forward_info.routing {
 						PendingHTLCRouting::Forward { short_channel_id, .. } => short_channel_id,
+						#[cfg(trampoline)]
+						PendingHTLCRouting::TrampolineForward { .. } => 0,
 						PendingHTLCRouting::Receive { .. } => 0,
 						PendingHTLCRouting::ReceiveKeysend { .. } => 0,
 					};
@@ -12448,6 +12474,7 @@ impl_writeable_tlv_based!(BlindedForward, {
 	(3, next_blinding_override, option),
 });
 
+#[cfg(not(trampoline))]
 impl_writeable_tlv_based_enum!(PendingHTLCRouting,
 	(0, Forward) => {
 		(0, onion_packet, required),
@@ -12476,6 +12503,42 @@ impl_writeable_tlv_based_enum!(PendingHTLCRouting,
 		(11, invoice_request, option),
 	},
 );
+#[cfg(trampoline)]
+impl_writeable_tlv_based_enum!(PendingHTLCRouting,
+	(0, Forward) => {
+		(0, onion_packet, required),
+		(1, blinded, option),
+		(2, short_channel_id, required),
+		(3, incoming_cltv_expiry, option),
+	},
+	(1, Receive) => {
+		(0, payment_data, required),
+		(1, phantom_shared_secret, option),
+		(2, incoming_cltv_expiry, required),
+		(3, payment_metadata, option),
+		(5, custom_tlvs, optional_vec),
+		(7, requires_blinded_error, (default_value, false)),
+		(9, payment_context, option),
+	},
+	(2, ReceiveKeysend) => {
+		(0, payment_preimage, required),
+		(1, requires_blinded_error, (default_value, false)),
+		(2, incoming_cltv_expiry, required),
+		(3, payment_metadata, option),
+		(4, payment_data, option), // Added in 0.0.116
+		(5, custom_tlvs, optional_vec),
+		(7, has_recipient_created_payment_secret, (default_value, false)),
+		(9, payment_context, option),
+		(11, invoice_request, option),
+	},
+	(3, TrampolineForward) => {
+		(0, incoming_shared_secret, required),
+		(2, onion_packet, required),
+		(4, blinded, option),
+		(6, node_id, required),
+		(8, incoming_cltv_expiry, required),
+	}
+);
 
 impl_writeable_tlv_based!(PendingHTLCInfo, {
 	(0, routing, required),

lightning/src/util/ser.rs

@@ -403,10 +403,10 @@ impl<T: Readable> MaybeReadable for T {
 ///
 /// This is not exported to bindings users as manual TLV building is not currently supported in bindings
 pub struct RequiredWrapper<T>(pub Option<T>);
-impl<T: Readable> Readable for RequiredWrapper<T> {
+impl<T: LengthReadable> LengthReadable for RequiredWrapper<T> {
 	#[inline]
-	fn read<R: Read>(reader: &mut R) -> Result<Self, DecodeError> {
-		Ok(Self(Some(Readable::read(reader)?)))
+	fn read_from_fixed_length_buffer<R: LengthRead>(reader: &mut R) -> Result<Self, DecodeError> {
+		Ok(Self(Some(LengthReadable::read_from_fixed_length_buffer(reader)?)))
 	}
 }
 impl<A, T: ReadableArgs<A>> ReadableArgs<A> for RequiredWrapper<T> {