Support NextHop::ShortChannelId in BlindedPath

[rust-lightning] / lightning / src / blinded_path / mod.rs

diff --git a/lightning/src/blinded_path/mod.rs b/lightning/src/blinded_path/mod.rs
index 07fa7b770249cae94e1ea18269b63805dc933f93..5abf53ec166561b351c17255eeaf7424cf2677fb 100644 (file)
--- a/lightning/src/blinded_path/mod.rs
+++ b/lightning/src/blinded_path/mod.rs
@@ -10,10 +10,11 @@
 //! Creating blinded paths and related utilities live here.
 
 pub mod payment;
-pub(crate) mod message;
+pub mod message;
 pub(crate) mod utils;
 
 use bitcoin::secp256k1::{self, PublicKey, Secp256k1, SecretKey};
+use core::ops::Deref;
 
 use crate::ln::msgs::DecodeError;
 use crate::offers::invoice::BlindedPayInfo;
@@ -24,6 +25,17 @@ use crate::util::ser::{Readable, Writeable, Writer};
 use crate::io;
 use crate::prelude::*;
 
+/// The next hop to forward an onion message along its path.
+///
+/// Note that payment blinded paths always specify their next hop using an explicit node id.
+#[derive(Clone, Debug, Hash, PartialEq, Eq)]
+pub enum NextMessageHop {
+       /// The node id of the next hop.
+       NodeId(PublicKey),
+       /// The short channel id leading to the next hop.
+       ShortChannelId(u64),
+}
+
 /// Onion messages and payments can be sent and received to blinded paths, which serve to hide the
 /// identity of the recipient.
 #[derive(Clone, Debug, Hash, PartialEq, Eq)]
@@ -89,6 +101,11 @@ impl NodeIdLookUp for EmptyNodeIdLookUp {
        }
 }
 
+impl Deref for EmptyNodeIdLookUp {
+       type Target = EmptyNodeIdLookUp;
+       fn deref(&self) -> &Self { self }
+}
+
 /// An encrypted payload and node id corresponding to a hop in a payment or onion message path, to
 /// be encoded in the sender's onion packet. These hops cannot be identified by outside observers
 /// and thus can be used to hide the identity of the recipient.
@@ -104,10 +121,10 @@ pub struct BlindedHop {
 
 impl BlindedPath {
        /// Create a one-hop blinded path for a message.
-       pub fn one_hop_for_message<ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification>(
-               recipient_node_id: PublicKey, entropy_source: &ES, secp_ctx: &Secp256k1<T>
-       ) -> Result<Self, ()> {
-               Self::new_for_message(&[recipient_node_id], entropy_source, secp_ctx)
+       pub fn one_hop_for_message<ES: Deref, T: secp256k1::Signing + secp256k1::Verification>(
+               recipient_node_id: PublicKey, entropy_source: ES, secp_ctx: &Secp256k1<T>
+       ) -> Result<Self, ()> where ES::Target: EntropySource {
+               Self::new_for_message(&[], recipient_node_id, entropy_source, secp_ctx)
        }
 
        /// Create a blinded path for an onion message, to be forwarded along `node_pks`. The last node
@@ -115,26 +132,30 @@ impl BlindedPath {
        ///
        /// Errors if no hops are provided or if `node_pk`(s) are invalid.
        //  TODO: make all payloads the same size with padding + add dummy hops
-       pub fn new_for_message<ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification>(
-               node_pks: &[PublicKey], entropy_source: &ES, secp_ctx: &Secp256k1<T>
-       ) -> Result<Self, ()> {
-               if node_pks.is_empty() { return Err(()) }
+       pub fn new_for_message<ES: Deref, T: secp256k1::Signing + secp256k1::Verification>(
+               intermediate_nodes: &[message::ForwardNode], recipient_node_id: PublicKey,
+               entropy_source: ES, secp_ctx: &Secp256k1<T>
+       ) -> Result<Self, ()> where ES::Target: EntropySource {
+               let introduction_node = IntroductionNode::NodeId(
+                       intermediate_nodes.first().map_or(recipient_node_id, |n| n.node_id)
+               );
                let blinding_secret_bytes = entropy_source.get_secure_random_bytes();
                let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
-               let introduction_node = IntroductionNode::NodeId(node_pks[0]);
 
                Ok(BlindedPath {
                        introduction_node,
                        blinding_point: PublicKey::from_secret_key(secp_ctx, &blinding_secret),
-                       blinded_hops: message::blinded_hops(secp_ctx, node_pks, &blinding_secret).map_err(|_| ())?,
+                       blinded_hops: message::blinded_hops(
+                               secp_ctx, intermediate_nodes, recipient_node_id, &blinding_secret,
+                       ).map_err(|_| ())?,
                })
        }
 
        /// Create a one-hop blinded path for a payment.
-       pub fn one_hop_for_payment<ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification>(
+       pub fn one_hop_for_payment<ES: Deref, T: secp256k1::Signing + secp256k1::Verification>(
                payee_node_id: PublicKey, payee_tlvs: payment::ReceiveTlvs, min_final_cltv_expiry_delta: u16,
-               entropy_source: &ES, secp_ctx: &Secp256k1<T>
-       ) -> Result<(BlindedPayInfo, Self), ()> {
+               entropy_source: ES, secp_ctx: &Secp256k1<T>
+       ) -> Result<(BlindedPayInfo, Self), ()> where ES::Target: EntropySource {
                // 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();
@@ -153,11 +174,11 @@ impl BlindedPath {
        ///
        /// [`ForwardTlvs`]: crate::blinded_path::payment::ForwardTlvs
        //  TODO: make all payloads the same size with padding + add dummy hops
-       pub fn new_for_payment<ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification>(
+       pub fn new_for_payment<ES: Deref, T: secp256k1::Signing + secp256k1::Verification>(
                intermediate_nodes: &[payment::ForwardNode], payee_node_id: PublicKey,
                payee_tlvs: payment::ReceiveTlvs, htlc_maximum_msat: u64, min_final_cltv_expiry_delta: u16,
-               entropy_source: &ES, secp_ctx: &Secp256k1<T>
-       ) -> Result<(BlindedPayInfo, Self), ()> {
+               entropy_source: ES, secp_ctx: &Secp256k1<T>
+       ) -> Result<(BlindedPayInfo, Self), ()> where ES::Target: EntropySource {
                let introduction_node = IntroductionNode::NodeId(
                        intermediate_nodes.first().map_or(payee_node_id, |n| n.node_id)
                );