///
/// [BOLT 7]: https://github.com/lightning/bolts/blob/master/07-routing-gossip.md#the-channel_announcement-message
/// [`ChannelAnnouncement`]: crate::ln::msgs::ChannelAnnouncement
-#[derive(Clone, Debug, Hash, PartialEq, Eq)]
+#[derive(Clone, Copy, Debug, Hash, PartialEq, Eq)]
pub enum Direction {
/// The lesser node id when compared lexicographically in ascending order.
NodeOne,
NodeTwo,
}
+/// An interface for looking up the node id of a channel counterparty for the purpose of forwarding
+/// an [`OnionMessage`].
+///
+/// [`OnionMessage`]: crate::ln::msgs::OnionMessage
+pub trait NodeIdLookUp {
+ /// Returns the node id of the forwarding node's channel counterparty with `short_channel_id`.
+ ///
+ /// Here, the forwarding node is referring to the node of the [`OnionMessenger`] parameterized
+ /// by the [`NodeIdLookUp`] and the counterparty to one of that node's peers.
+ ///
+ /// [`OnionMessenger`]: crate::onion_message::messenger::OnionMessenger
+ fn next_node_id(&self, short_channel_id: u64) -> Option<PublicKey>;
+}
+
+/// A [`NodeIdLookUp`] that always returns `None`.
+pub struct EmptyNodeIdLookUp {}
+
+impl NodeIdLookUp for EmptyNodeIdLookUp {
+ fn next_node_id(&self, _short_channel_id: u64) -> Option<PublicKey> {
+ None
+ }
+}
+
/// 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.
Direction::NodeTwo => core::cmp::max(node_a, node_b),
}
}
+
+ /// Returns the [`PublicKey`] from the inputs corresponding to the direction.
+ pub fn select_pubkey<'a>(&self, node_a: &'a PublicKey, node_b: &'a PublicKey) -> &'a PublicKey {
+ let (node_one, node_two) = if NodeId::from_pubkey(node_a) < NodeId::from_pubkey(node_b) {
+ (node_a, node_b)
+ } else {
+ (node_b, node_a)
+ };
+ match self {
+ Direction::NodeOne => node_one,
+ Direction::NodeTwo => node_two,
+ }
+ }
}