Clarify docs regarding one-hop blinded paths

The docs assumed ChannelManager is parameterized by DefaultRouter, which
may not be the case. Clarify the behavior is specific to using
DefaultRouter.

diff --git a/lightning/src/ln/channelmanager.rs b/lightning/src/ln/channelmanager.rs
index 7e81730ce7d731435a25765d1036a5ffb9beb33c..992fd3c6f02d258c82a570e40567ddc2049b06c3 100644 (file)
--- a/lightning/src/ln/channelmanager.rs
+++ b/lightning/src/ln/channelmanager.rs
@@ -8261,10 +8261,8 @@ macro_rules! create_offer_builder { ($self: ident, $builder: ty) => {
        ///
        /// Uses [`MessageRouter`] to construct a [`BlindedPath`] for the offer based on the given
        /// `absolute_expiry` according to [`MAX_SHORT_LIVED_RELATIVE_EXPIRY`]. See those docs for
-       /// privacy implications. However, if one is not found, uses a one-hop [`BlindedPath`] with
-       /// [`ChannelManager::get_our_node_id`] as the introduction node instead. In the latter case,
-       /// the node must be announced, otherwise, there is no way to find a path to the introduction
-       /// node in order to send the [`InvoiceRequest`].
+       /// privacy implications as well as those of the parameterized [`Router`], which implements
+       /// [`MessageRouter`].
        ///
        /// Also, uses a derived signing pubkey in the offer for recipient privacy.
        ///
@@ -8329,10 +8327,8 @@ macro_rules! create_refund_builder { ($self: ident, $builder: ty) => {
        ///
        /// Uses [`MessageRouter`] to construct a [`BlindedPath`] for the refund based on the given
        /// `absolute_expiry` according to [`MAX_SHORT_LIVED_RELATIVE_EXPIRY`]. See those docs for
-       /// privacy implications. However, if one is not found, uses a one-hop [`BlindedPath`] with
-       /// [`ChannelManager::get_our_node_id`] as the introduction node instead. In the latter case,
-       /// the node must be announced, otherwise, there is no way to find a path to the introduction
-       /// node in order to send the [`Bolt12Invoice`].
+       /// privacy implications as well as those of the parameterized [`Router`], which implements
+       /// [`MessageRouter`].
        ///
        /// Also, uses a derived payer id in the refund for payer privacy.
        ///
@@ -8431,10 +8427,9 @@ where
        ///
        /// # Privacy
        ///
-       /// Uses a one-hop [`BlindedPath`] for the reply path with [`ChannelManager::get_our_node_id`]
-       /// as the introduction node and a derived payer id for payer privacy. As such, currently, the
-       /// node must be announced. Otherwise, there is no way to find a path to the introduction node
-       /// in order to send the [`Bolt12Invoice`].
+       /// For payer privacy, uses a derived payer id and uses [`MessageRouter::create_blinded_paths`]
+       /// to construct a [`BlindedPath`] for the reply path. For further privacy implications, see the
+       /// docs of the parameterized [`Router`], which implements [`MessageRouter`].
        ///
        /// # Limitations
        ///

diff --git a/lightning/src/onion_message/messenger.rs b/lightning/src/onion_message/messenger.rs
index 5ceb0683c57203396da6612a6e2e7835c4c2f8bc..ee49d00e99dea2de48c8a9c2fa76e92c2c2b9b27 100644 (file)
--- a/lightning/src/onion_message/messenger.rs
+++ b/lightning/src/onion_message/messenger.rs
@@ -456,6 +456,13 @@ pub trait MessageRouter {
 }
 
 /// A [`MessageRouter`] that can only route to a directly connected [`Destination`].
+///
+/// # Privacy
+///
+/// Creating [`BlindedPath`]s may affect privacy since, if a suitable path cannot be found, it will
+/// create a one-hop path using the recipient as the introduction node if it is a announced node.
+/// Otherwise, there is no way to find a path to the introduction node in order to send a message,
+/// and thus an `Err` is returned.
 pub struct DefaultMessageRouter<G: Deref<Target=NetworkGraph<L>>, L: Deref, ES: Deref>
 where
        L::Target: Logger,

diff --git a/lightning/src/routing/router.rs b/lightning/src/routing/router.rs
index c105e914679c05f147ee9f477a4a55dc60a6a7b9..5b202604e371a5624a5cce671f2ec3fbe44a7eab 100644 (file)
--- a/lightning/src/routing/router.rs
+++ b/lightning/src/routing/router.rs
@@ -36,6 +36,11 @@ use core::{cmp, fmt};
 use core::ops::Deref;
 
 /// A [`Router`] implemented using [`find_route`].
+///
+/// # Privacy
+///
+/// Implements [`MessageRouter`] by delegating to [`DefaultMessageRouter`]. See those docs for
+/// privacy implications.
 pub struct DefaultRouter<G: Deref<Target = NetworkGraph<L>> + Clone, L: Deref, ES: Deref, S: Deref, SP: Sized, Sc: ScoreLookUp<ScoreParams = SP>> where
        L::Target: Logger,
        S::Target: for <'a> LockableScore<'a, ScoreLookUp = Sc>,