X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fblinded_path%2Fmessage.rs;h=3a5541fa1468272f3859972bca2cdfb4f8053ee8;hb=ab4b87209886569ba94df10ee27dccf9c0562d05;hp=024fb451d00a78d1fe42a0524b042cfe3f42b9ec;hpb=381cc646c66538f69599ae4ee1224783eb5abe6a;p=rust-lightning

diff --git a/lightning/src/blinded_path/message.rs b/lightning/src/blinded_path/message.rs
index 024fb451..3a5541fa 100644
--- a/lightning/src/blinded_path/message.rs
+++ b/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::packet::ControlTlvs;
 use crate::prelude::*;
-use crate::util::ser::{Writeable, Writer};
+use crate::sign::{NodeSigner, Recipient};
+use crate::crypto::streams::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`].
@@ -48,32 +57,41 @@ impl Writeable for ReceiveTlvs {
 pub(super) fn blinded_hops<T: secp256k1::Signing + secp256k1::Verification>(
 	secp_ctx: &Secp256k1<T>, unblinded_path: &[PublicKey], session_priv: &SecretKey
 ) -> Result<Vec<BlindedHop>, secp256k1::Error> {
-	let mut blinded_hops = Vec::with_capacity(unblinded_path.len());
-
-	let mut prev_ss_and_blinded_node_id = None;
-	utils::construct_keys_callback(secp_ctx, unblinded_path, None, session_priv, |blinded_node_id, _, _, encrypted_payload_ss, unblinded_pk, _| {
-		if let Some((prev_ss, prev_blinded_node_id)) = prev_ss_and_blinded_node_id {
-			if let Some(pk) = unblinded_pk {
-				let payload = ForwardTlvs {
-					next_node_id: pk,
-					next_blinding_override: None,
-				};
-				blinded_hops.push(BlindedHop {
-					blinded_node_id: prev_blinded_node_id,
-					encrypted_payload: utils::encrypt_payload(payload, prev_ss),
-				});
-			} else { debug_assert!(false); }
-		}
-		prev_ss_and_blinded_node_id = Some((encrypted_payload_ss, blinded_node_id));
-	})?;
+	let blinded_tlvs = unblinded_path.iter()
+		.skip(1) // The first node's TLVs contains the next node's pubkey
+		.map(|pk| {
+			ControlTlvs::Forward(ForwardTlvs { next_node_id: *pk, next_blinding_override: None })
+		})
+		.chain(core::iter::once(ControlTlvs::Receive(ReceiveTlvs { path_id: None })));
 
-	if let Some((final_ss, final_blinded_node_id)) = prev_ss_and_blinded_node_id {
-		let final_payload = ReceiveTlvs { path_id: None };
-		blinded_hops.push(BlindedHop {
-			blinded_node_id: final_blinded_node_id,
-			encrypted_payload: utils::encrypt_payload(final_payload, final_ss),
-		});
-	} else { debug_assert!(false) }
+	utils::construct_blinded_hops(secp_ctx, unblinded_path.iter(), blinded_tlvs, session_priv)
+}
 
-	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(())
+	}
 }