- // 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(())
- }
+ /// Create a one-hop blinded path for a payment.
+ pub fn one_hop_for_payment<ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification>(
+ payee_node_id: PublicKey, payee_tlvs: payment::ReceiveTlvs, entropy_source: &ES,
+ secp_ctx: &Secp256k1<T>
+ ) -> Result<(BlindedPayInfo, Self), ()> {
+ // This value is not considered in pathfinding for 1-hop blinded paths, because it's intended to
+ // be in relation to a specific channel.
+ let htlc_maximum_msat = u64::max_value();
+ Self::new_for_payment(
+ &[], payee_node_id, payee_tlvs, htlc_maximum_msat, entropy_source, secp_ctx
+ )
+ }
+
+ /// Create a blinded path for a payment, to be forwarded along `intermediate_nodes`.
+ ///
+ /// Errors if:
+ /// * a provided node id is invalid
+ /// * [`BlindedPayInfo`] calculation results in an integer overflow
+ /// * any unknown features are required in the provided [`ForwardTlvs`]
+ ///
+ /// [`ForwardTlvs`]: crate::blinded_path::payment::ForwardTlvs
+ // TODO: make all payloads the same size with padding + add dummy hops
+ pub(crate) fn new_for_payment<ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification>(
+ intermediate_nodes: &[payment::ForwardNode], payee_node_id: PublicKey,
+ payee_tlvs: payment::ReceiveTlvs, htlc_maximum_msat: u64, entropy_source: &ES,
+ secp_ctx: &Secp256k1<T>
+ ) -> Result<(BlindedPayInfo, Self), ()> {
+ let blinding_secret_bytes = entropy_source.get_secure_random_bytes();
+ let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
+
+ let blinded_payinfo = payment::compute_payinfo(intermediate_nodes, &payee_tlvs, htlc_maximum_msat)?;
+ Ok((blinded_payinfo, BlindedPath {
+ introduction_node_id: intermediate_nodes.first().map_or(payee_node_id, |n| n.node_id),
+ blinding_point: PublicKey::from_secret_key(secp_ctx, &blinding_secret),
+ blinded_hops: payment::blinded_hops(
+ secp_ctx, intermediate_nodes, payee_node_id, payee_tlvs, &blinding_secret
+ ).map_err(|_| ())?,
+ }))