Merge pull request #3072 from arik-so/arik/gossip-v2-parsing

[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 7f4cfe2e3008eb25e46ed8a8dc10a21bf13a6a7b..2d3d085bddf35d51a5276c5c9c048506527ac45b 100644 (file)
--- a/lightning/src/blinded_path/mod.rs
+++ b/lightning/src/blinded_path/mod.rs
@@ -10,7 +10,7 @@
 //! 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};
@@ -21,6 +21,7 @@ use crate::offers::invoice::BlindedPayInfo;
 use crate::routing::gossip::{NodeId, ReadOnlyNetworkGraph};
 use crate::sign::EntropySource;
 use crate::util::ser::{Readable, Writeable, Writer};
+use crate::util::scid_utils;
 
 use crate::io;
 use crate::prelude::*;
@@ -124,7 +125,7 @@ impl BlindedPath {
        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)
+               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
@@ -133,17 +134,21 @@ 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: Deref, T: secp256k1::Signing + secp256k1::Verification>(
-               node_pks: &[PublicKey], entropy_source: ES, secp_ctx: &Secp256k1<T>
+               intermediate_nodes: &[message::ForwardNode], recipient_node_id: PublicKey,
+               entropy_source: ES, secp_ctx: &Secp256k1<T>
        ) -> Result<Self, ()> where ES::Target: EntropySource {
-               if node_pks.is_empty() { return Err(()) }
+               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(|_| ())?,
                })
        }
 
@@ -213,6 +218,35 @@ impl BlindedPath {
                        },
                }
        }
+
+       /// Attempts to a use a compact representation for the [`IntroductionNode`] by using a directed
+       /// short channel id from a channel in `network_graph` leading to the introduction node.
+       ///
+       /// While this may result in a smaller encoding, there is a trade off in that the path may
+       /// become invalid if the channel is closed or hasn't been propagated via gossip. Therefore,
+       /// calling this may not be suitable for long-lived blinded paths.
+       pub fn use_compact_introduction_node(&mut self, network_graph: &ReadOnlyNetworkGraph) {
+               if let IntroductionNode::NodeId(pubkey) = &self.introduction_node {
+                       let node_id = NodeId::from_pubkey(pubkey);
+                       if let Some(node_info) = network_graph.node(&node_id) {
+                               if let Some((scid, channel_info)) = node_info
+                                       .channels
+                                       .iter()
+                                       .filter_map(|scid| network_graph.channel(*scid).map(|info| (*scid, info)))
+                                       .min_by_key(|(scid, _)| scid_utils::block_from_scid(*scid))
+                               {
+                                       let direction = if node_id == channel_info.node_one {
+                                               Direction::NodeOne
+                                       } else {
+                                               debug_assert_eq!(node_id, channel_info.node_two);
+                                               Direction::NodeTwo
+                                       };
+                                       self.introduction_node =
+                                               IntroductionNode::DirectedShortChannelId(direction, scid);
+                               }
+                       }
+               }
+       }
 }
 
 impl Writeable for BlindedPath {