Include a one-hop blinded path in Offer and Refund

While this doesn't add much privacy over not including any blinded
paths, it allows us to exercise code for receiving on blinded paths.

diff --git a/lightning/src/blinded_path/mod.rs b/lightning/src/blinded_path/mod.rs
index 896999799fbebed4456f8c53768881698d4e581f..1415836c01fee6cacaa8d2808f28d6d9ecfba37a 100644 (file)
--- a/lightning/src/blinded_path/mod.rs
+++ b/lightning/src/blinded_path/mod.rs
@@ -57,7 +57,7 @@ pub struct BlindedHop {
 
 impl BlindedPath {
        /// Create a one-hop blinded path for a message.
-       pub fn one_hop_for_message<ES: EntropySource, T: secp256k1::Signing + secp256k1::Verification>(
+       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)
@@ -68,7 +68,7 @@ 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, T: secp256k1::Signing + secp256k1::Verification>(
+       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(()) }

diff --git a/lightning/src/ln/channelmanager.rs b/lightning/src/ln/channelmanager.rs
index 3810cfb8171eeca169e29eb5b36f68ca5b23fdfe..113d690215599d87618b535ab6259bab89635a69 100644 (file)
--- a/lightning/src/ln/channelmanager.rs
+++ b/lightning/src/ln/channelmanager.rs
@@ -30,6 +30,7 @@ use bitcoin::secp256k1::{SecretKey,PublicKey};
 use bitcoin::secp256k1::Secp256k1;
 use bitcoin::{LockTime, secp256k1, Sequence};
 
+use crate::blinded_path::BlindedPath;
 use crate::chain;
 use crate::chain::{Confirm, ChannelMonitorUpdateStatus, Watch, BestBlock};
 use crate::chain::chaininterface::{BroadcasterInterface, ConfirmationTarget, FeeEstimator, LowerBoundedFeeEstimator};
@@ -7130,6 +7131,11 @@ where
        /// [`ChannelManager`] when handling [`InvoiceRequest`] messages for the offer. The offer will
        /// not have an expiration unless otherwise set on the builder.
        ///
+       /// Uses a one-hop [`BlindedPath`] for the offer with [`ChannelManager::get_our_node_id`] as the
+       /// introduction node and a derived signing pubkey for recipient 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 [`InvoiceRequest`].
+       ///
        /// [`Offer`]: crate::offers::offer::Offer
        /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
        pub fn create_offer_builder(
@@ -7139,10 +7145,11 @@ where
                let expanded_key = &self.inbound_payment_key;
                let entropy = &*self.entropy_source;
                let secp_ctx = &self.secp_ctx;
+               let path = self.create_one_hop_blinded_path();
 
-               // TODO: Set blinded paths
                OfferBuilder::deriving_signing_pubkey(description, node_id, expanded_key, entropy, secp_ctx)
                        .chain_hash(self.chain_hash)
+                       .path(path)
        }
 
        /// Creates a [`RefundBuilder`] such that the [`Refund`] it builds is recognized by the
@@ -7152,6 +7159,11 @@ where
        ///
        /// The provided `payment_id` is used to ensure that only one invoice is paid for the refund.
        ///
+       /// Uses a one-hop [`BlindedPath`] for the refund with [`ChannelManager::get_our_node_id`] as
+       /// the introduction node and a derived payer id for sender 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`].
+       ///
        /// [`Refund`]: crate::offers::refund::Refund
        /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
        pub fn create_refund_builder(
@@ -7162,13 +7174,14 @@ where
                let expanded_key = &self.inbound_payment_key;
                let entropy = &*self.entropy_source;
                let secp_ctx = &self.secp_ctx;
+               let path = self.create_one_hop_blinded_path();
 
-               // TODO: Set blinded paths
                let builder = RefundBuilder::deriving_payer_id(
                        description, node_id, expanded_key, entropy, secp_ctx, amount_msats, payment_id
                )?
                        .chain_hash(self.chain_hash)
-                       .absolute_expiry(absolute_expiry);
+                       .absolute_expiry(absolute_expiry)
+                       .path(path);
 
                self.pending_outbound_payments
                        .add_new_awaiting_invoice(
@@ -7279,6 +7292,14 @@ where
                inbound_payment::get_payment_preimage(payment_hash, payment_secret, &self.inbound_payment_key)
        }
 
+       /// Creates a one-hop blinded path with [`ChannelManager::get_our_node_id`] as the introduction
+       /// node.
+       fn create_one_hop_blinded_path(&self) -> BlindedPath {
+               let entropy_source = self.entropy_source.deref();
+               let secp_ctx = &self.secp_ctx;
+               BlindedPath::one_hop_for_message(self.get_our_node_id(), entropy_source, secp_ctx).unwrap()
+       }
+
        /// Gets a fake short channel id for use in receiving [phantom node payments]. These fake scids
        /// are used when constructing the phantom invoice's route hints.
        ///

diff --git a/lightning/src/routing/router.rs b/lightning/src/routing/router.rs
index 4c8a31bd73533fdf3ca4d19b869c8339edcc2167..104f4c93c3871aca1f0e6f3af73a959e9c13001f 100644 (file)
--- a/lightning/src/routing/router.rs
+++ b/lightning/src/routing/router.rs
@@ -90,6 +90,7 @@ pub trait Router {
                &self, payer: &PublicKey, route_params: &RouteParameters,
                first_hops: Option<&[&ChannelDetails]>, inflight_htlcs: InFlightHtlcs
        ) -> Result<Route, LightningError>;
+
        /// Finds a [`Route`] for a payment between the given `payer` and a payee.
        ///
        /// The `payee` and the payment's value are given in [`RouteParameters::payment_params`]