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`].
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(())
+ }
}