Move blinded message path util into message submodule

Author: valentinewallace

lightning/src/blinded_path/message.rs

@@ -1,9 +1,18 @@
 use bitcoin::secp256k1::{self, PublicKey, Secp256k1, SecretKey};
-use crate::blinded_path::BlindedHop;
+
+use crate::blinded_path::{BlindedHop, BlindedPath};
 use crate::blinded_path::utils;
 use crate::io;
+use crate::io::Cursor;
+use crate::ln::onion_utils;
+use crate::onion_message::ControlTlvs;
 use crate::prelude::*;
-use crate::util::ser::{Writeable, Writer};
+use crate::sign::{NodeSigner, Recipient};
+use crate::util::chacha20poly1305rfc::ChaChaPolyReadAdapter;
+use crate::util::ser::{FixedLengthReader, LengthReadableArgs, Writeable, Writer};
+
+use core::mem;
+use core::ops::Deref;
 
 /// TLVs to encode in an intermediate onion message packet's hop data. When provided in a blinded
 /// route, they are encoded into [`BlindedHop::encrypted_payload`].
@@ -77,3 +86,32 @@ pub(super) fn blinded_hops<T: secp256k1::Signing + secp256k1::Verification>(
 
 	Ok(blinded_hops)
 }
+
+// Advance the blinded onion message path by one hop, so make the second hop into the new
+// introduction node.
+pub(crate) fn advance_path_by_one<NS: Deref, T: secp256k1::Signing + secp256k1::Verification>(
+	path: &mut BlindedPath, node_signer: &NS, secp_ctx: &Secp256k1<T>
+) -> Result<(), ()> where NS::Target: NodeSigner {
+	let control_tlvs_ss = node_signer.ecdh(Recipient::Node, &path.blinding_point, None)?;
+	let rho = onion_utils::gen_rho_from_shared_secret(&control_tlvs_ss.secret_bytes());
+	let encrypted_control_tlvs = path.blinded_hops.remove(0).encrypted_payload;
+	let mut s = Cursor::new(&encrypted_control_tlvs);
+	let mut reader = FixedLengthReader::new(&mut s, encrypted_control_tlvs.len() as u64);
+	match ChaChaPolyReadAdapter::read(&mut reader, rho) {
+		Ok(ChaChaPolyReadAdapter { readable: ControlTlvs::Forward(ForwardTlvs {
+			mut next_node_id, next_blinding_override,
+		})}) => {
+			let mut new_blinding_point = match next_blinding_override {
+				Some(blinding_point) => blinding_point,
+				None => {
+					onion_utils::next_hop_pubkey(secp_ctx, path.blinding_point,
+						control_tlvs_ss.as_ref()).map_err(|_| ())?
+				}
+			};
+			mem::swap(&mut path.blinding_point, &mut new_blinding_point);
+			mem::swap(&mut path.introduction_node_id, &mut next_node_id);
+			Ok(())
+		},
+		_ => Err(())
+	}
+}

lightning/src/blinded_path/mod.rs

@@ -14,16 +14,11 @@ pub(crate) mod utils;
 
 use bitcoin::secp256k1::{self, PublicKey, Secp256k1, SecretKey};
 
-use crate::sign::{EntropySource, NodeSigner, Recipient};
-use crate::onion_message::ControlTlvs;
+use crate::sign::EntropySource;
 use crate::ln::msgs::DecodeError;
-use crate::ln::onion_utils;
-use crate::util::chacha20poly1305rfc::ChaChaPolyReadAdapter;
-use crate::util::ser::{FixedLengthReader, LengthReadableArgs, Readable, Writeable, Writer};
+use crate::util::ser::{Readable, Writeable, Writer};
 
-use core::mem;
-use core::ops::Deref;
-use crate::io::{self, Cursor};
+use crate::io;
 use crate::prelude::*;
 
 /// Onion messages and payments can be sent and received to blinded paths, which serve to hide the
@@ -77,36 +72,6 @@ impl BlindedPath {
 			blinded_hops: message::blinded_hops(secp_ctx, node_pks, &blinding_secret).map_err(|_| ())?,
 		})
 	}
-
-	// Advance the blinded onion message path by one hop, so make the second hop into the new
-	// introduction node.
-	pub(super) fn advance_message_path_by_one<NS: Deref, T: secp256k1::Signing + secp256k1::Verification>
-		(&mut self, node_signer: &NS, secp_ctx: &Secp256k1<T>) -> Result<(), ()>
-		where NS::Target: NodeSigner
-	{
-		let control_tlvs_ss = node_signer.ecdh(Recipient::Node, &self.blinding_point, None)?;
-		let rho = onion_utils::gen_rho_from_shared_secret(&control_tlvs_ss.secret_bytes());
-		let encrypted_control_tlvs = self.blinded_hops.remove(0).encrypted_payload;
-		let mut s = Cursor::new(&encrypted_control_tlvs);
-		let mut reader = FixedLengthReader::new(&mut s, encrypted_control_tlvs.len() as u64);
-		match ChaChaPolyReadAdapter::read(&mut reader, rho) {
-			Ok(ChaChaPolyReadAdapter { readable: ControlTlvs::Forward(message::ForwardTlvs {
-				mut next_node_id, next_blinding_override,
-			})}) => {
-				let mut new_blinding_point = match next_blinding_override {
-					Some(blinding_point) => blinding_point,
-					None => {
-						onion_utils::next_hop_pubkey(secp_ctx, self.blinding_point,
-							control_tlvs_ss.as_ref()).map_err(|_| ())?
-					}
-				};
-				mem::swap(&mut self.blinding_point, &mut new_blinding_point);
-				mem::swap(&mut self.introduction_node_id, &mut next_node_id);
-				Ok(())
-			},
-			_ => Err(())
-		}
-	}
 }
 
 impl Writeable for BlindedPath {

lightning/src/onion_message/messenger.rs

@@ -16,7 +16,7 @@ use bitcoin::hashes::sha256::Hash as Sha256;
 use bitcoin::secp256k1::{self, PublicKey, Scalar, Secp256k1, SecretKey};
 
 use crate::blinded_path::BlindedPath;
-use crate::blinded_path::message::{ForwardTlvs, ReceiveTlvs};
+use crate::blinded_path::message::{advance_path_by_one, ForwardTlvs, ReceiveTlvs};
 use crate::blinded_path::utils;
 use crate::sign::{EntropySource, KeysManager, NodeSigner, Recipient};
 use crate::events::OnionMessageProvider;
@@ -299,7 +299,7 @@ where
 				let our_node_id = self.node_signer.get_node_id(Recipient::Node)
 					.map_err(|()| SendError::GetNodeIdFailed)?;
 				if blinded_path.introduction_node_id == our_node_id {
-					blinded_path.advance_message_path_by_one(&self.node_signer, &self.secp_ctx)
+					advance_path_by_one(blinded_path, &self.node_signer, &self.secp_ctx)
 						.map_err(|()| SendError::BlindedPathAdvanceFailed)?;
 				}
 			}