X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fblinded_path%2Fpayment.rs;h=7df7d1c63edd1ed8222b2b9e470b235671d14d82;hb=07d991c82fadf10f59ae01b2b5aef6bc8797fd9a;hp=ec441c18c986ed4788948dcf09465e07233878d8;hpb=8367e021103493b811b9366e2355bd09e91b4836;p=rust-lightning

diff --git a/lightning/src/blinded_path/payment.rs b/lightning/src/blinded_path/payment.rs
index ec441c18..7df7d1c6 100644
--- a/lightning/src/blinded_path/payment.rs
+++ b/lightning/src/blinded_path/payment.rs
@@ -1,20 +1,36 @@
+// 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.
+
 //! Data structures and methods for constructing [`BlindedPath`]s to send a payment over.
 //!
 //! [`BlindedPath`]: crate::blinded_path::BlindedPath
 
 use bitcoin::secp256k1::{self, PublicKey, Secp256k1, SecretKey};
 
-use crate::blinded_path::BlindedHop;
+use crate::blinded_path::{BlindedHop, BlindedPath, IntroductionNode, NodeIdLookUp};
 use crate::blinded_path::utils;
+use crate::crypto::streams::ChaChaPolyReadAdapter;
 use crate::io;
-use crate::ln::PaymentSecret;
-use crate::ln::channelmanager::CounterpartyForwardingInfo;
+use crate::io::Cursor;
+use crate::ln::types::PaymentSecret;
+use crate::ln::channel_state::CounterpartyForwardingInfo;
 use crate::ln::features::BlindedHopFeatures;
 use crate::ln::msgs::DecodeError;
+use crate::ln::onion_utils;
 use crate::offers::invoice::BlindedPayInfo;
 use crate::offers::invoice_request::InvoiceRequestFields;
 use crate::offers::offer::OfferId;
-use crate::util::ser::{HighZeroBytesDroppedBigSize, Readable, Writeable, Writer};
+use crate::sign::{NodeSigner, Recipient};
+use crate::util::ser::{FixedLengthReader, LengthReadableArgs, HighZeroBytesDroppedBigSize, Readable, Writeable, Writer};
+
+use core::mem;
+use core::ops::Deref;
 
 #[allow(unused_imports)]
 use crate::prelude::*;
@@ -265,6 +281,43 @@ pub(super) fn blinded_hops<T: secp256k1::Signing + secp256k1::Verification>(
 	utils::construct_blinded_hops(secp_ctx, pks, tlvs, session_priv)
 }
 
+// Advance the blinded onion payment path by one hop, so make the second hop into the new
+// introduction node.
+//
+// Will only modify `path` when returning `Ok`.
+pub(crate) fn advance_path_by_one<NS: Deref, NL: Deref, T>(
+	path: &mut BlindedPath, node_signer: &NS, node_id_lookup: &NL, secp_ctx: &Secp256k1<T>
+) -> Result<(), ()>
+where
+	NS::Target: NodeSigner,
+	NL::Target: NodeIdLookUp,
+	T: secp256k1::Signing + secp256k1::Verification,
+{
+	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.get(0).ok_or(())?.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: BlindedPaymentTlvs::Forward(ForwardTlvs { short_channel_id, .. })
+		}) => {
+			let next_node_id = match node_id_lookup.next_node_id(short_channel_id) {
+				Some(node_id) => node_id,
+				None => return Err(()),
+			};
+			let mut new_blinding_point = 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);
+			path.introduction_node = IntroductionNode::NodeId(next_node_id);
+			path.blinded_hops.remove(0);
+			Ok(())
+		},
+		_ => Err(())
+	}
+}
+
 /// `None` if underflow occurs.
 pub(crate) fn amt_to_forward_msat(inbound_amt_msat: u64, payment_relay: &PaymentRelay) -> Option<u64> {
 	let inbound_amt = inbound_amt_msat as u128;
@@ -425,7 +478,7 @@ impl_writeable_tlv_based!(Bolt12RefundContext, {});
 mod tests {
 	use bitcoin::secp256k1::PublicKey;
 	use crate::blinded_path::payment::{ForwardNode, ForwardTlvs, ReceiveTlvs, PaymentConstraints, PaymentContext, PaymentRelay};
-	use crate::ln::PaymentSecret;
+	use crate::ln::types::PaymentSecret;
 	use crate::ln::features::BlindedHopFeatures;
 	use crate::ln::functional_test_utils::TEST_FINAL_CLTV;