Add CandidateRouteHop::Blinded and ::OneHopBlinded variant

It's unclear what values 1-hop blinded paths should set their BlindedPayInfos
to, because those values are meant to refer to the fees/cltv delta on the path
*between* the intro node and the destination. We zero out these values in the
new variant's methods so they don't mess with path finding/construction.

diff --git a/lightning/src/routing/router.rs b/lightning/src/routing/router.rs
index c0a0d0eb9991f4f931b2239c0b0210271a273873..2f153412cd8804e1a20d23ff67d41e20cd5ef461 100644 (file)
--- a/lightning/src/routing/router.rs
+++ b/lightning/src/routing/router.rs
@@ -939,10 +939,24 @@ enum CandidateRouteHop<'a> {
                info: DirectedChannelInfo<'a>,
                short_channel_id: u64,
        },
-       /// A hop to the payee found in the payment invoice, though not necessarily a direct channel.
+       /// A hop to the payee found in the BOLT 11 payment invoice, though not necessarily a direct
+       /// channel.
        PrivateHop {
                hint: &'a RouteHintHop,
-       }
+       },
+       /// The payee's identity is concealed behind blinded paths provided in a BOLT 12 invoice.
+       Blinded {
+               hint: &'a (BlindedPayInfo, BlindedPath),
+               hint_idx: usize,
+       },
+       /// Similar to [`Self::Blinded`], but the path here has 1 blinded hop. `BlindedPayInfo` provided
+       /// for 1-hop blinded paths is ignored because it is meant to apply to the hops *between* the
+       /// introduction node and the destination. Useful for tracking that we need to include a blinded
+       /// path at the end of our [`Route`].
+       OneHopBlinded {
+               hint: &'a (BlindedPayInfo, BlindedPath),
+               hint_idx: usize,
+       },
 }
 
 impl<'a> CandidateRouteHop<'a> {
@@ -951,6 +965,8 @@ impl<'a> CandidateRouteHop<'a> {
                        CandidateRouteHop::FirstHop { details } => Some(details.get_outbound_payment_scid().unwrap()),
                        CandidateRouteHop::PublicHop { short_channel_id, .. } => Some(*short_channel_id),
                        CandidateRouteHop::PrivateHop { hint } => Some(hint.short_channel_id),
+                       CandidateRouteHop::Blinded { .. } => None,
+                       CandidateRouteHop::OneHopBlinded { .. } => None,
                }
        }
 
@@ -960,6 +976,8 @@ impl<'a> CandidateRouteHop<'a> {
                        CandidateRouteHop::FirstHop { details } => details.counterparty.features.to_context(),
                        CandidateRouteHop::PublicHop { info, .. } => info.channel().features.clone(),
                        CandidateRouteHop::PrivateHop { .. } => ChannelFeatures::empty(),
+                       CandidateRouteHop::Blinded { .. } => ChannelFeatures::empty(),
+                       CandidateRouteHop::OneHopBlinded { .. } => ChannelFeatures::empty(),
                }
        }
 
@@ -968,6 +986,8 @@ impl<'a> CandidateRouteHop<'a> {
                        CandidateRouteHop::FirstHop { .. } => 0,
                        CandidateRouteHop::PublicHop { info, .. } => info.direction().cltv_expiry_delta as u32,
                        CandidateRouteHop::PrivateHop { hint } => hint.cltv_expiry_delta as u32,
+                       CandidateRouteHop::Blinded { hint, .. } => hint.0.cltv_expiry_delta as u32,
+                       CandidateRouteHop::OneHopBlinded { .. } => 0,
                }
        }
 
@@ -976,6 +996,8 @@ impl<'a> CandidateRouteHop<'a> {
                        CandidateRouteHop::FirstHop { details } => details.next_outbound_htlc_minimum_msat,
                        CandidateRouteHop::PublicHop { info, .. } => info.direction().htlc_minimum_msat,
                        CandidateRouteHop::PrivateHop { hint } => hint.htlc_minimum_msat.unwrap_or(0),
+                       CandidateRouteHop::Blinded { hint, .. } => hint.0.htlc_minimum_msat,
+                       CandidateRouteHop::OneHopBlinded { .. } => 0,
                }
        }
 
@@ -986,6 +1008,14 @@ impl<'a> CandidateRouteHop<'a> {
                        },
                        CandidateRouteHop::PublicHop { info, .. } => info.direction().fees,
                        CandidateRouteHop::PrivateHop { hint } => hint.fees,
+                       CandidateRouteHop::Blinded { hint, .. } => {
+                               RoutingFees {
+                                       base_msat: hint.0.fee_base_msat,
+                                       proportional_millionths: hint.0.fee_proportional_millionths
+                               }
+                       },
+                       CandidateRouteHop::OneHopBlinded { .. } =>
+                               RoutingFees { base_msat: 0, proportional_millionths: 0 },
                }
        }
 
@@ -999,10 +1029,16 @@ impl<'a> CandidateRouteHop<'a> {
                                EffectiveCapacity::HintMaxHTLC { amount_msat: *max },
                        CandidateRouteHop::PrivateHop { hint: RouteHintHop { htlc_maximum_msat: None, .. }} =>
                                EffectiveCapacity::Infinite,
+                       CandidateRouteHop::Blinded { hint, .. } =>
+                               EffectiveCapacity::HintMaxHTLC { amount_msat: hint.0.htlc_maximum_msat },
+                       CandidateRouteHop::OneHopBlinded { .. } => EffectiveCapacity::Infinite,
                }
        }
+
        fn id(&self, channel_direction: bool /* src_node_id < target_node_id */) -> CandidateHopId {
                match self {
+                       CandidateRouteHop::Blinded { hint_idx, .. } => CandidateHopId::Blinded(*hint_idx),
+                       CandidateRouteHop::OneHopBlinded { hint_idx, .. } => CandidateHopId::Blinded(*hint_idx),
                        _ => CandidateHopId::Clear((self.short_channel_id().unwrap(), channel_direction)),
                }
        }
@@ -1259,6 +1295,12 @@ struct LoggedCandidateHop<'a>(&'a CandidateRouteHop<'a>);
 impl<'a> fmt::Display for LoggedCandidateHop<'a> {
        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
                match self.0 {
+                       CandidateRouteHop::Blinded { hint, .. } | CandidateRouteHop::OneHopBlinded { hint, .. } => {
+                               "blinded route hint with introduction node id ".fmt(f)?;
+                               hint.1.introduction_node_id.fmt(f)?;
+                               " and blinding point ".fmt(f)?;
+                               hint.1.blinding_point.fmt(f)
+                       },
                        _ => {
                                "SCID ".fmt(f)?;
                                self.0.short_channel_id().unwrap().fmt(f)