Merge pull request #1273 from jkczyz/2022-01-invoice-expiry
[rust-lightning] / lightning / src / util / events.rs
index 46ab9f74924e453b5446c27a783616cab0a0ff5d..a4a733c8e503eff05212d6570ada728a4cb95c1e 100644 (file)
@@ -153,10 +153,13 @@ impl_writeable_tlv_based_enum_upgradable!(ClosureReason,
 #[derive(Clone, Debug)]
 pub enum Event {
        /// Used to indicate that the client should generate a funding transaction with the given
-       /// parameters and then call ChannelManager::funding_transaction_generated.
-       /// Generated in ChannelManager message handling.
+       /// parameters and then call [`ChannelManager::funding_transaction_generated`].
+       /// Generated in [`ChannelManager`] message handling.
        /// Note that *all inputs* in the funding transaction must spend SegWit outputs or your
        /// counterparty can steal your funds!
+       ///
+       /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
+       /// [`ChannelManager::funding_transaction_generated`]: crate::ln::channelmanager::ChannelManager::funding_transaction_generated
        FundingGenerationReady {
                /// The random channel_id we picked which you'll need to pass into
                /// ChannelManager::funding_transaction_generated.
@@ -180,10 +183,15 @@ pub enum Event {
        /// [`ChannelManager::fail_htlc_backwards`] within the HTLC's timeout, the HTLC will be
        /// automatically failed.
        ///
+       /// # Note
+       /// LDK will not stop an inbound payment from being paid multiple times, so multiple
+       /// `PaymentReceived` events may be generated for the same payment.
+       ///
        /// [`ChannelManager::claim_funds`]: crate::ln::channelmanager::ChannelManager::claim_funds
        /// [`ChannelManager::fail_htlc_backwards`]: crate::ln::channelmanager::ChannelManager::fail_htlc_backwards
        PaymentReceived {
-               /// The hash for which the preimage should be handed to the ChannelManager.
+               /// The hash for which the preimage should be handed to the ChannelManager. Note that LDK will
+               /// not stop you from registering duplicate payment hashes for inbound payments.
                payment_hash: PaymentHash,
                /// The value, in thousandths of a satoshi, that this payment is for.
                amt: u64,
@@ -222,14 +230,20 @@ pub enum Event {
                /// [`Route::get_total_fees`]: crate::routing::router::Route::get_total_fees
                fee_paid_msat: Option<u64>,
        },
-       /// Indicates an outbound payment we made failed. Probably some intermediary node dropped
+       /// Indicates an outbound HTLC we sent failed. Probably some intermediary node dropped
        /// something. You may wish to retry with a different route.
+       ///
+       /// Note that this does *not* indicate that all paths for an MPP payment have failed, see
+       /// [`Event::PaymentFailed`] and [`all_paths_failed`].
+       ///
+       /// [`all_paths_failed`]: Self::all_paths_failed
        PaymentPathFailed {
                /// The id returned by [`ChannelManager::send_payment`] and used with
-               /// [`ChannelManager::retry_payment`].
+               /// [`ChannelManager::retry_payment`] and [`ChannelManager::abandon_payment`].
                ///
                /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
                /// [`ChannelManager::retry_payment`]: crate::ln::channelmanager::ChannelManager::retry_payment
+               /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
                payment_id: Option<PaymentId>,
                /// The hash that was given to [`ChannelManager::send_payment`].
                ///
@@ -251,6 +265,20 @@ pub enum Event {
                /// For both single-path and multi-path payments, this is set if all paths of the payment have
                /// failed. This will be set to false if (1) this is an MPP payment and (2) other parts of the
                /// larger MPP payment were still in flight when this event was generated.
+               ///
+               /// Note that if you are retrying individual MPP parts, using this value to determine if a
+               /// payment has fully failed is race-y. Because multiple failures can happen prior to events
+               /// being processed, you may retry in response to a first failure, with a second failure
+               /// (with `all_paths_failed` set) still pending. Then, when the second failure is processed
+               /// you will see `all_paths_failed` set even though the retry of the first failure still
+               /// has an associated in-flight HTLC. See (1) for an example of such a failure.
+               ///
+               /// If you wish to retry individual MPP parts and learn when a payment has failed, you must
+               /// call [`ChannelManager::abandon_payment`] and wait for a [`Event::PaymentFailed`] event.
+               ///
+               /// (1) <https://github.com/lightningdevkit/rust-lightning/issues/1164>
+               ///
+               /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
                all_paths_failed: bool,
                /// The payment path that failed.
                path: Vec<RouteHop>,
@@ -271,8 +299,31 @@ pub enum Event {
 #[cfg(test)]
                error_data: Option<Vec<u8>>,
        },
-       /// Used to indicate that ChannelManager::process_pending_htlc_forwards should be called at a
-       /// time in the future.
+       /// Indicates an outbound payment failed. Individual [`Event::PaymentPathFailed`] events
+       /// provide failure information for each MPP part in the payment.
+       ///
+       /// This event is provided once there are no further pending HTLCs for the payment and the
+       /// payment is no longer retryable, either due to a several-block timeout or because
+       /// [`ChannelManager::abandon_payment`] was previously called for the corresponding payment.
+       ///
+       /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
+       PaymentFailed {
+               /// The id returned by [`ChannelManager::send_payment`] and used with
+               /// [`ChannelManager::retry_payment`] and [`ChannelManager::abandon_payment`].
+               ///
+               /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
+               /// [`ChannelManager::retry_payment`]: crate::ln::channelmanager::ChannelManager::retry_payment
+               /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
+               payment_id: PaymentId,
+               /// The hash that was given to [`ChannelManager::send_payment`].
+               ///
+               /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
+               payment_hash: PaymentHash,
+       },
+       /// Used to indicate that [`ChannelManager::process_pending_htlc_forwards`] should be called at
+       /// a time in the future.
+       ///
+       /// [`ChannelManager::process_pending_htlc_forwards`]: crate::ln::channelmanager::ChannelManager::process_pending_htlc_forwards
        PendingHTLCsForwardable {
                /// The minimum amount of time that should be waited prior to calling
                /// process_pending_htlc_forwards. To increase the effort required to correlate payments,
@@ -457,6 +508,13 @@ impl Writeable for Event {
                                        (4, path, vec_type)
                                })
                        },
+                       &Event::PaymentFailed { ref payment_id, ref payment_hash } => {
+                               15u8.write(writer)?;
+                               write_tlv_fields!(writer, {
+                                       (0, payment_id, required),
+                                       (2, payment_hash, required),
+                               })
+                       },
                        // Note that, going forward, all new events must only write data inside of
                        // `write_tlv_fields`. Versions 0.0.101+ will ignore odd-numbered events that write
                        // data via `write_tlv_fields`.
@@ -634,6 +692,21 @@ impl MaybeReadable for Event {
                                };
                                f()
                        },
+                       15u8 => {
+                               let f = || {
+                                       let mut payment_hash = PaymentHash([0; 32]);
+                                       let mut payment_id = PaymentId([0; 32]);
+                                       read_tlv_fields!(reader, {
+                                               (0, payment_id, required),
+                                               (2, payment_hash, required),
+                                       });
+                                       Ok(Some(Event::PaymentFailed {
+                                               payment_id,
+                                               payment_hash,
+                                       }))
+                               };
+                               f()
+                       },
                        // Versions prior to 0.0.100 did not ignore odd types, instead returning InvalidValue.
                        // Version 0.0.100 failed to properly ignore odd types, possibly resulting in corrupt
                        // reads.