Track SCID aliases from our counterparty and use them in invoices

[rust-lightning] / lightning / src / ln / channelmanager.rs

diff --git a/lightning/src/ln/channelmanager.rs b/lightning/src/ln/channelmanager.rs
index 6d067c24a1edf40333e5f4800d77c793444be709..46bad1f56566cb0eb802fc60fe88592d66b5a3d8 100644 (file)
--- a/lightning/src/ln/channelmanager.rs
+++ b/lightning/src/ln/channelmanager.rs
@@ -1188,7 +1188,20 @@ pub struct ChannelDetails {
        pub funding_txo: Option<OutPoint>,
        /// The position of the funding transaction in the chain. None if the funding transaction has
        /// not yet been confirmed and the channel fully opened.
+       ///
+       /// Note that if [`inbound_scid_alias`] is set, it must be used for invoices and inbound
+       /// payments instead of this. See [`get_inbound_payment_scid`].
+       ///
+       /// [`inbound_scid_alias`]: Self::inbound_scid_alias
+       /// [`get_inbound_payment_scid`]: Self::get_inbound_payment_scid
        pub short_channel_id: Option<u64>,
+       /// An optional [`short_channel_id`] alias for this channel, randomly generated by our
+       /// counterparty and usable in place of [`short_channel_id`] in invoice route hints. Our
+       /// counterparty will recognize the alias provided here in place of the [`short_channel_id`]
+       /// when they see a payment to be routed to us.
+       ///
+       /// [`short_channel_id`]: Self::short_channel_id
+       pub inbound_scid_alias: Option<u64>,
        /// The value, in satoshis, of this channel as appears in the funding output
        pub channel_value_satoshis: u64,
        /// The value, in satoshis, that must always be held in the channel for us. This value ensures
@@ -1274,6 +1287,15 @@ pub struct ChannelDetails {
        pub is_public: bool,
 }
 
+impl ChannelDetails {
+       /// Gets the SCID which should be used to identify this channel for inbound payments. This
+       /// should be used for providing invoice hints or in any other context where our counterparty
+       /// will forward a payment to us.
+       pub fn get_inbound_payment_scid(&self) -> Option<u64> {
+               self.inbound_scid_alias.or(self.short_channel_id)
+       }
+}
+
 /// If a payment fails to send, it can be in one of several states. This enum is returned as the
 /// Err() type describing which state the payment is in, see the description of individual enum
 /// states for more.
@@ -1833,6 +1855,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                        },
                                        funding_txo: channel.get_funding_txo(),
                                        short_channel_id: channel.get_short_channel_id(),
+                                       inbound_scid_alias: channel.latest_inbound_scid_alias(),
                                        channel_value_satoshis: channel.get_value_satoshis(),
                                        unspendable_punishment_reserve: to_self_reserve_satoshis,
                                        balance_msat,
@@ -5973,6 +5996,7 @@ impl_writeable_tlv_based!(ChannelCounterparty, {
 });
 
 impl_writeable_tlv_based!(ChannelDetails, {
+       (1, inbound_scid_alias, option),
        (2, channel_id, required),
        (4, counterparty, required),
        (6, funding_txo, option),