Refactor PaymentReceived event for keysend receives
[rust-lightning] / lightning / src / util / events.rs
index 0fc7c6b3a3d166096019407784b929588ddbddd8..876dfe6abb551f359a6c67c60fe05c1d104b81ed 100644 (file)
@@ -27,6 +27,45 @@ use prelude::*;
 use core::time::Duration;
 use core::ops::Deref;
 
+/// Some information provided on receipt of payment depends on whether the payment received is a
+/// spontaneous payment or a "conventional" lightning payment that's paying an invoice.
+#[derive(Clone, Debug)]
+pub enum PaymentPurpose {
+       /// Information for receiving a payment that we generated an invoice for.
+       InvoicePayment {
+               /// The preimage to the payment_hash, if the payment hash (and secret) were fetched via
+               /// [`ChannelManager::create_inbound_payment`]. If provided, this can be handed directly to
+               /// [`ChannelManager::claim_funds`].
+               ///
+               /// [`ChannelManager::create_inbound_payment`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment
+               /// [`ChannelManager::claim_funds`]: crate::ln::channelmanager::ChannelManager::claim_funds
+               payment_preimage: Option<PaymentPreimage>,
+               /// The "payment secret". This authenticates the sender to the recipient, preventing a
+               /// number of deanonymization attacks during the routing process.
+               /// It is provided here for your reference, however its accuracy is enforced directly by
+               /// [`ChannelManager`] using the values you previously provided to
+               /// [`ChannelManager::create_inbound_payment`] or
+               /// [`ChannelManager::create_inbound_payment_for_hash`].
+               ///
+               /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
+               /// [`ChannelManager::create_inbound_payment`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment
+               /// [`ChannelManager::create_inbound_payment_for_hash`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment_for_hash
+               payment_secret: PaymentSecret,
+               /// This is the `user_payment_id` which was provided to
+               /// [`ChannelManager::create_inbound_payment_for_hash`] or
+               /// [`ChannelManager::create_inbound_payment`]. It has no meaning inside of LDK and is
+               /// simply copied here. It may be used to correlate PaymentReceived events with invoice
+               /// metadata stored elsewhere.
+               ///
+               /// [`ChannelManager::create_inbound_payment`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment
+               /// [`ChannelManager::create_inbound_payment_for_hash`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment_for_hash
+               user_payment_id: u64,
+       },
+       /// Because this is a spontaneous payment, the payer generated their own preimage rather than us
+       /// (the payee) providing a preimage.
+       SpontaneousPayment(PaymentPreimage),
+}
+
 /// An Event which you should probably take some action in response to.
 ///
 /// Note that while Writeable and Readable are implemented for Event, you probably shouldn't use
@@ -63,37 +102,13 @@ pub enum Event {
        PaymentReceived {
                /// The hash for which the preimage should be handed to the ChannelManager.
                payment_hash: PaymentHash,
-               /// The preimage to the payment_hash, if the payment hash (and secret) were fetched via
-               /// [`ChannelManager::create_inbound_payment`]. If provided, this can be handed directly to
-               /// [`ChannelManager::claim_funds`].
-               ///
-               /// [`ChannelManager::create_inbound_payment`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment
-               /// [`ChannelManager::claim_funds`]: crate::ln::channelmanager::ChannelManager::claim_funds
-               payment_preimage: Option<PaymentPreimage>,
-               /// The "payment secret". This authenticates the sender to the recipient, preventing a
-               /// number of deanonymization attacks during the routing process.
-               /// It is provided here for your reference, however its accuracy is enforced directly by
-               /// [`ChannelManager`] using the values you previously provided to
-               /// [`ChannelManager::create_inbound_payment`] or
-               /// [`ChannelManager::create_inbound_payment_for_hash`].
-               ///
-               /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
-               /// [`ChannelManager::create_inbound_payment`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment
-               /// [`ChannelManager::create_inbound_payment_for_hash`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment_for_hash
-               payment_secret: PaymentSecret,
                /// The value, in thousandths of a satoshi, that this payment is for. Note that you must
                /// compare this to the expected value before accepting the payment (as otherwise you are
                /// providing proof-of-payment for less than the value you expected!).
                amt: u64,
-               /// This is the `user_payment_id` which was provided to
-               /// [`ChannelManager::create_inbound_payment_for_hash`] or
-               /// [`ChannelManager::create_inbound_payment`]. It has no meaning inside of LDK and is
-               /// simply copied here. It may be used to correlate PaymentReceived events with invoice
-               /// metadata stored elsewhere.
-               ///
-               /// [`ChannelManager::create_inbound_payment`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment
-               /// [`ChannelManager::create_inbound_payment_for_hash`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment_for_hash
-               user_payment_id: u64,
+               /// Information for claiming this received payment, based on whether the purpose of the
+               /// payment is to pay an invoice or to send a spontaneous payment.
+               purpose: PaymentPurpose,
        },
        /// Indicates an outbound payment we made succeeded (ie it made it all the way to its target
        /// and we got back the payment preimage for it).
@@ -145,13 +160,26 @@ impl Writeable for Event {
                                // We never write out FundingGenerationReady events as, upon disconnection, peers
                                // drop any channels which have not yet exchanged funding_signed.
                        },
-                       &Event::PaymentReceived { ref payment_hash, ref payment_preimage, ref payment_secret, ref amt, ref user_payment_id } => {
+                       &Event::PaymentReceived { ref payment_hash, ref amt, ref purpose } => {
                                1u8.write(writer)?;
+                               let mut payment_secret = None;
+                               let mut user_payment_id = None;
+                               let payment_preimage;
+                               match &purpose {
+                                       PaymentPurpose::InvoicePayment { payment_preimage: preimage, payment_secret: secret, user_payment_id: id } => {
+                                               payment_secret = Some(secret);
+                                               payment_preimage = *preimage;
+                                               user_payment_id = Some(id);
+                                       },
+                                       PaymentPurpose::SpontaneousPayment(preimage) => {
+                                               payment_preimage = Some(*preimage);
+                                       }
+                               }
                                write_tlv_fields!(writer, {
                                        (0, payment_hash, required),
-                                       (2, payment_secret, required),
+                                       (2, payment_secret, option),
                                        (4, amt, required),
-                                       (6, user_payment_id, required),
+                                       (6, user_payment_id, option),
                                        (8, payment_preimage, option),
                                });
                        },
@@ -201,22 +229,31 @@ impl MaybeReadable for Event {
                                let f = || {
                                        let mut payment_hash = PaymentHash([0; 32]);
                                        let mut payment_preimage = None;
-                                       let mut payment_secret = PaymentSecret([0; 32]);
+                                       let mut payment_secret = None;
                                        let mut amt = 0;
-                                       let mut user_payment_id = 0;
+                                       let mut user_payment_id = None;
                                        read_tlv_fields!(reader, {
                                                (0, payment_hash, required),
-                                               (2, payment_secret, required),
+                                               (2, payment_secret, option),
                                                (4, amt, required),
-                                               (6, user_payment_id, required),
+                                               (6, user_payment_id, option),
                                                (8, payment_preimage, option),
                                        });
+                                       let purpose = match payment_secret {
+                                               Some(secret) => PaymentPurpose::InvoicePayment {
+                                                       payment_preimage,
+                                                       payment_secret: secret,
+                                                       user_payment_id: if let Some(id) = user_payment_id {
+                                                               id
+                                                       } else { return Err(msgs::DecodeError::InvalidValue) }
+                                               },
+                                               None if payment_preimage.is_some() => PaymentPurpose::SpontaneousPayment(payment_preimage.unwrap()),
+                                               None => return Err(msgs::DecodeError::InvalidValue),
+                                       };
                                        Ok(Some(Event::PaymentReceived {
                                                payment_hash,
-                                               payment_preimage,
-                                               payment_secret,
                                                amt,
-                                               user_payment_id,
+                                               purpose,
                                        }))
                                };
                                f()