1 // This file is Copyright its original authors, visible in version control
4 // This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
5 // or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
7 // You may not use this file except in accordance with one or both of these
10 //! Events are returned from various bits in the library which indicate some action must be taken
13 //! Because we don't have a built-in runtime, it's up to the client to call events at a time in the
14 //! future, as well as generate and broadcast funding transactions handle payment preimages and a
17 pub mod bump_transaction;
19 pub use bump_transaction::BumpTransactionEvent;
21 use crate::sign::SpendableOutputDescriptor;
22 use crate::ln::channelmanager::{InterceptId, PaymentId, RecipientOnionFields};
23 use crate::ln::channel::FUNDING_CONF_DEADLINE_BLOCKS;
24 use crate::ln::features::ChannelTypeFeatures;
26 use crate::ln::{PaymentPreimage, PaymentHash, PaymentSecret};
27 use crate::routing::gossip::NetworkUpdate;
28 use crate::util::errors::APIError;
29 use crate::util::ser::{BigSize, FixedLengthReader, Writeable, Writer, MaybeReadable, Readable, RequiredWrapper, UpgradableRequired, WithoutLength};
30 use crate::util::string::UntrustedString;
31 use crate::routing::router::{BlindedTail, Path, RouteHop, RouteParameters};
33 use bitcoin::{PackedLockTime, Transaction, OutPoint};
34 use bitcoin::blockdata::script::Script;
35 use bitcoin::hashes::Hash;
36 use bitcoin::hashes::sha256::Hash as Sha256;
37 use bitcoin::secp256k1::PublicKey;
39 use crate::prelude::*;
40 use core::time::Duration;
44 /// Some information provided on receipt of payment depends on whether the payment received is a
45 /// spontaneous payment or a "conventional" lightning payment that's paying an invoice.
46 #[derive(Clone, Debug, PartialEq, Eq)]
47 pub enum PaymentPurpose {
48 /// Information for receiving a payment that we generated an invoice for.
50 /// The preimage to the payment_hash, if the payment hash (and secret) were fetched via
51 /// [`ChannelManager::create_inbound_payment`]. If provided, this can be handed directly to
52 /// [`ChannelManager::claim_funds`].
54 /// [`ChannelManager::create_inbound_payment`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment
55 /// [`ChannelManager::claim_funds`]: crate::ln::channelmanager::ChannelManager::claim_funds
56 payment_preimage: Option<PaymentPreimage>,
57 /// The "payment secret". This authenticates the sender to the recipient, preventing a
58 /// number of deanonymization attacks during the routing process.
59 /// It is provided here for your reference, however its accuracy is enforced directly by
60 /// [`ChannelManager`] using the values you previously provided to
61 /// [`ChannelManager::create_inbound_payment`] or
62 /// [`ChannelManager::create_inbound_payment_for_hash`].
64 /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
65 /// [`ChannelManager::create_inbound_payment`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment
66 /// [`ChannelManager::create_inbound_payment_for_hash`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment_for_hash
67 payment_secret: PaymentSecret,
69 /// Because this is a spontaneous payment, the payer generated their own preimage rather than us
70 /// (the payee) providing a preimage.
71 SpontaneousPayment(PaymentPreimage),
74 impl_writeable_tlv_based_enum!(PaymentPurpose,
75 (0, InvoicePayment) => {
76 (0, payment_preimage, option),
77 (2, payment_secret, required),
79 (2, SpontaneousPayment)
82 /// When the payment path failure took place and extra details about it. [`PathFailure::OnPath`] may
83 /// contain a [`NetworkUpdate`] that needs to be applied to the [`NetworkGraph`].
85 /// [`NetworkUpdate`]: crate::routing::gossip::NetworkUpdate
86 /// [`NetworkGraph`]: crate::routing::gossip::NetworkGraph
87 #[derive(Clone, Debug, Eq, PartialEq)]
88 pub enum PathFailure {
89 /// We failed to initially send the payment and no HTLC was committed to. Contains the relevant
92 /// The error surfaced from initial send.
95 /// A hop on the path failed to forward our payment.
97 /// If present, this [`NetworkUpdate`] should be applied to the [`NetworkGraph`] so that routing
98 /// decisions can take into account the update.
100 /// [`NetworkUpdate`]: crate::routing::gossip::NetworkUpdate
101 /// [`NetworkGraph`]: crate::routing::gossip::NetworkGraph
102 network_update: Option<NetworkUpdate>,
106 impl_writeable_tlv_based_enum_upgradable!(PathFailure,
108 (0, network_update, upgradable_option),
110 (2, InitialSend) => {
111 (0, err, upgradable_required),
115 #[derive(Clone, Debug, PartialEq, Eq)]
116 /// The reason the channel was closed. See individual variants for more details.
117 pub enum ClosureReason {
118 /// Closure generated from receiving a peer error message.
120 /// Our counterparty may have broadcasted their latest commitment state, and we have
122 CounterpartyForceClosed {
123 /// The error which the peer sent us.
125 /// Be careful about printing the peer_msg, a well-crafted message could exploit
126 /// a security vulnerability in the terminal emulator or the logging subsystem.
127 /// To be safe, use `Display` on `UntrustedString`
129 /// [`UntrustedString`]: crate::util::string::UntrustedString
130 peer_msg: UntrustedString,
132 /// Closure generated from [`ChannelManager::force_close_channel`], called by the user.
134 /// [`ChannelManager::force_close_channel`]: crate::ln::channelmanager::ChannelManager::force_close_channel.
136 /// The channel was closed after negotiating a cooperative close and we've now broadcasted
137 /// the cooperative close transaction. Note the shutdown may have been initiated by us.
138 //TODO: split between CounterpartyInitiated/LocallyInitiated
140 /// A commitment transaction was confirmed on chain, closing the channel. Most likely this
141 /// commitment transaction came from our counterparty, but it may also have come from
142 /// a copy of our own `ChannelMonitor`.
143 CommitmentTxConfirmed,
144 /// The funding transaction failed to confirm in a timely manner on an inbound channel.
146 /// Closure generated from processing an event, likely a HTLC forward/relay/reception.
148 /// A developer-readable error message which we generated.
151 /// The peer disconnected prior to funding completing. In this case the spec mandates that we
152 /// forget the channel entirely - we can attempt again if the peer reconnects.
154 /// This includes cases where we restarted prior to funding completion, including prior to the
155 /// initial [`ChannelMonitor`] persistence completing.
157 /// In LDK versions prior to 0.0.107 this could also occur if we were unable to connect to the
158 /// peer because of mutual incompatibility between us and our channel counterparty.
160 /// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
162 /// Closure generated from `ChannelManager::read` if the [`ChannelMonitor`] is newer than
163 /// the [`ChannelManager`] deserialized.
165 /// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
166 /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
167 OutdatedChannelManager,
168 /// The counterparty requested a cooperative close of a channel that had not been funded yet.
169 /// The channel has been immediately closed.
170 CounterpartyCoopClosedUnfundedChannel,
173 impl core::fmt::Display for ClosureReason {
174 fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
175 f.write_str("Channel closed because ")?;
177 ClosureReason::CounterpartyForceClosed { peer_msg } => {
178 f.write_fmt(format_args!("counterparty force-closed with message: {}", peer_msg))
180 ClosureReason::HolderForceClosed => f.write_str("user manually force-closed the channel"),
181 ClosureReason::CooperativeClosure => f.write_str("the channel was cooperatively closed"),
182 ClosureReason::CommitmentTxConfirmed => f.write_str("commitment or closing transaction was confirmed on chain."),
183 ClosureReason::FundingTimedOut => write!(f, "funding transaction failed to confirm within {} blocks", FUNDING_CONF_DEADLINE_BLOCKS),
184 ClosureReason::ProcessingError { err } => {
185 f.write_str("of an exception: ")?;
188 ClosureReason::DisconnectedPeer => f.write_str("the peer disconnected prior to the channel being funded"),
189 ClosureReason::OutdatedChannelManager => f.write_str("the ChannelManager read from disk was stale compared to ChannelMonitor(s)"),
190 ClosureReason::CounterpartyCoopClosedUnfundedChannel => f.write_str("the peer requested the unfunded channel be closed"),
195 impl_writeable_tlv_based_enum_upgradable!(ClosureReason,
196 (0, CounterpartyForceClosed) => { (1, peer_msg, required) },
197 (1, FundingTimedOut) => {},
198 (2, HolderForceClosed) => {},
199 (6, CommitmentTxConfirmed) => {},
200 (4, CooperativeClosure) => {},
201 (8, ProcessingError) => { (1, err, required) },
202 (10, DisconnectedPeer) => {},
203 (12, OutdatedChannelManager) => {},
204 (13, CounterpartyCoopClosedUnfundedChannel) => {},
207 /// Intended destination of a failed HTLC as indicated in [`Event::HTLCHandlingFailed`].
208 #[derive(Clone, Debug, PartialEq, Eq)]
209 pub enum HTLCDestination {
210 /// We tried forwarding to a channel but failed to do so. An example of such an instance is when
211 /// there is insufficient capacity in our outbound channel.
213 /// The `node_id` of the next node. For backwards compatibility, this field is
214 /// marked as optional, versions prior to 0.0.110 may not always be able to provide
215 /// counterparty node information.
216 node_id: Option<PublicKey>,
217 /// The outgoing `channel_id` between us and the next node.
218 channel_id: [u8; 32],
220 /// Scenario where we are unsure of the next node to forward the HTLC to.
222 /// Short channel id we are requesting to forward an HTLC to.
223 requested_forward_scid: u64,
225 /// We couldn't forward to the outgoing scid. An example would be attempting to send a duplicate
228 /// Short channel id we are requesting to forward an HTLC to.
229 requested_forward_scid: u64
231 /// Failure scenario where an HTLC may have been forwarded to be intended for us,
232 /// but is invalid for some reason, so we reject it.
234 /// Some of the reasons may include:
236 /// * Excess HTLCs for a payment that we have already fully received, over-paying for the
238 /// * The counterparty node modified the HTLC in transit,
239 /// * A probing attack where an intermediary node is trying to detect if we are the ultimate
240 /// recipient for a payment.
242 /// The payment hash of the payment we attempted to process.
243 payment_hash: PaymentHash
247 impl_writeable_tlv_based_enum_upgradable!(HTLCDestination,
248 (0, NextHopChannel) => {
249 (0, node_id, required),
250 (2, channel_id, required),
252 (1, InvalidForward) => {
253 (0, requested_forward_scid, required),
255 (2, UnknownNextHop) => {
256 (0, requested_forward_scid, required),
258 (4, FailedPayment) => {
259 (0, payment_hash, required),
263 /// Will be used in [`Event::HTLCIntercepted`] to identify the next hop in the HTLC's path.
264 /// Currently only used in serialization for the sake of maintaining compatibility. More variants
265 /// will be added for general-purpose HTLC forward intercepts as well as trampoline forward
266 /// intercepts in upcoming work.
267 enum InterceptNextHop {
269 requested_next_hop_scid: u64,
273 impl_writeable_tlv_based_enum!(InterceptNextHop,
275 (0, requested_next_hop_scid, required),
279 /// The reason the payment failed. Used in [`Event::PaymentFailed`].
280 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
281 pub enum PaymentFailureReason {
282 /// The intended recipient rejected our payment.
284 /// The user chose to abandon this payment by calling [`ChannelManager::abandon_payment`].
286 /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
288 /// We exhausted all of our retry attempts while trying to send the payment, or we
289 /// exhausted the [`Retry::Timeout`] if the user set one. If at any point a retry
290 /// attempt failed while being forwarded along the path, an [`Event::PaymentPathFailed`] will
291 /// have come before this.
293 /// [`Retry::Timeout`]: crate::ln::channelmanager::Retry::Timeout
295 /// The payment expired while retrying, based on the provided
296 /// [`PaymentParameters::expiry_time`].
298 /// [`PaymentParameters::expiry_time`]: crate::routing::router::PaymentParameters::expiry_time
300 /// We failed to find a route while retrying the payment.
302 /// This error should generally never happen. This likely means that there is a problem with
307 impl_writeable_tlv_based_enum!(PaymentFailureReason,
308 (0, RecipientRejected) => {},
309 (2, UserAbandoned) => {},
310 (4, RetriesExhausted) => {},
311 (6, PaymentExpired) => {},
312 (8, RouteNotFound) => {},
313 (10, UnexpectedError) => {}, ;
316 /// An Event which you should probably take some action in response to.
318 /// Note that while Writeable and Readable are implemented for Event, you probably shouldn't use
319 /// them directly as they don't round-trip exactly (for example FundingGenerationReady is never
320 /// written as it makes no sense to respond to it after reconnecting to peers).
321 #[derive(Clone, Debug, PartialEq, Eq)]
323 /// Used to indicate that the client should generate a funding transaction with the given
324 /// parameters and then call [`ChannelManager::funding_transaction_generated`].
325 /// Generated in [`ChannelManager`] message handling.
326 /// Note that *all inputs* in the funding transaction must spend SegWit outputs or your
327 /// counterparty can steal your funds!
329 /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
330 /// [`ChannelManager::funding_transaction_generated`]: crate::ln::channelmanager::ChannelManager::funding_transaction_generated
331 FundingGenerationReady {
332 /// The random channel_id we picked which you'll need to pass into
333 /// [`ChannelManager::funding_transaction_generated`].
335 /// [`ChannelManager::funding_transaction_generated`]: crate::ln::channelmanager::ChannelManager::funding_transaction_generated
336 temporary_channel_id: [u8; 32],
337 /// The counterparty's node_id, which you'll need to pass back into
338 /// [`ChannelManager::funding_transaction_generated`].
340 /// [`ChannelManager::funding_transaction_generated`]: crate::ln::channelmanager::ChannelManager::funding_transaction_generated
341 counterparty_node_id: PublicKey,
342 /// The value, in satoshis, that the output should have.
343 channel_value_satoshis: u64,
344 /// The script which should be used in the transaction output.
345 output_script: Script,
346 /// The `user_channel_id` value passed in to [`ChannelManager::create_channel`], or a
347 /// random value for an inbound channel. This may be zero for objects serialized with LDK
348 /// versions prior to 0.0.113.
350 /// [`ChannelManager::create_channel`]: crate::ln::channelmanager::ChannelManager::create_channel
351 user_channel_id: u128,
353 /// Indicates that we've been offered a payment and it needs to be claimed via calling
354 /// [`ChannelManager::claim_funds`] with the preimage given in [`PaymentPurpose`].
356 /// Note that if the preimage is not known, you should call
357 /// [`ChannelManager::fail_htlc_backwards`] or [`ChannelManager::fail_htlc_backwards_with_reason`]
358 /// to free up resources for this HTLC and avoid network congestion.
360 /// If [`Event::PaymentClaimable::onion_fields`] is `Some`, and includes custom TLVs with even type
361 /// numbers, you should use [`ChannelManager::fail_htlc_backwards_with_reason`] with
362 /// [`FailureCode::InvalidOnionPayload`] if you fail to understand and handle the contents, or
363 /// [`ChannelManager::claim_funds_with_known_custom_tlvs`] upon successful handling.
364 /// If you don't intend to check for custom TLVs, you can simply use
365 /// [`ChannelManager::claim_funds`], which will automatically fail back even custom TLVs.
367 /// If you fail to call [`ChannelManager::claim_funds`],
368 /// [`ChannelManager::claim_funds_with_known_custom_tlvs`],
369 /// [`ChannelManager::fail_htlc_backwards`], or
370 /// [`ChannelManager::fail_htlc_backwards_with_reason`] within the HTLC's timeout, the HTLC will
371 /// be automatically failed.
374 /// LDK will not stop an inbound payment from being paid multiple times, so multiple
375 /// `PaymentClaimable` events may be generated for the same payment. In such a case it is
376 /// polite (and required in the lightning specification) to fail the payment the second time
377 /// and give the sender their money back rather than accepting double payment.
380 /// This event used to be called `PaymentReceived` in LDK versions 0.0.112 and earlier.
382 /// [`ChannelManager::claim_funds`]: crate::ln::channelmanager::ChannelManager::claim_funds
383 /// [`ChannelManager::claim_funds_with_known_custom_tlvs`]: crate::ln::channelmanager::ChannelManager::claim_funds_with_known_custom_tlvs
384 /// [`FailureCode::InvalidOnionPayload`]: crate::ln::channelmanager::FailureCode::InvalidOnionPayload
385 /// [`ChannelManager::fail_htlc_backwards`]: crate::ln::channelmanager::ChannelManager::fail_htlc_backwards
386 /// [`ChannelManager::fail_htlc_backwards_with_reason`]: crate::ln::channelmanager::ChannelManager::fail_htlc_backwards_with_reason
388 /// The node that will receive the payment after it has been claimed.
389 /// This is useful to identify payments received via [phantom nodes].
390 /// This field will always be filled in when the event was generated by LDK versions
391 /// 0.0.113 and above.
393 /// [phantom nodes]: crate::sign::PhantomKeysManager
394 receiver_node_id: Option<PublicKey>,
395 /// The hash for which the preimage should be handed to the ChannelManager. Note that LDK will
396 /// not stop you from registering duplicate payment hashes for inbound payments.
397 payment_hash: PaymentHash,
398 /// The fields in the onion which were received with each HTLC. Only fields which were
399 /// identical in each HTLC involved in the payment will be included here.
401 /// Payments received on LDK versions prior to 0.0.115 will have this field unset.
402 onion_fields: Option<RecipientOnionFields>,
403 /// The value, in thousandths of a satoshi, that this payment is claimable for. May be greater
404 /// than the invoice amount.
406 /// May be less than the invoice amount if [`ChannelConfig::accept_underpaying_htlcs`] is set
407 /// and the previous hop took an extra fee.
410 /// If [`ChannelConfig::accept_underpaying_htlcs`] is set and you claim without verifying this
411 /// field, you may lose money!
413 /// [`ChannelConfig::accept_underpaying_htlcs`]: crate::util::config::ChannelConfig::accept_underpaying_htlcs
415 /// The value, in thousands of a satoshi, that was skimmed off of this payment as an extra fee
416 /// taken by our channel counterparty.
418 /// Will always be 0 unless [`ChannelConfig::accept_underpaying_htlcs`] is set.
420 /// [`ChannelConfig::accept_underpaying_htlcs`]: crate::util::config::ChannelConfig::accept_underpaying_htlcs
421 counterparty_skimmed_fee_msat: u64,
422 /// Information for claiming this received payment, based on whether the purpose of the
423 /// payment is to pay an invoice or to send a spontaneous payment.
424 purpose: PaymentPurpose,
425 /// The `channel_id` indicating over which channel we received the payment.
426 via_channel_id: Option<[u8; 32]>,
427 /// The `user_channel_id` indicating over which channel we received the payment.
428 via_user_channel_id: Option<u128>,
429 /// The block height at which this payment will be failed back and will no longer be
430 /// eligible for claiming.
432 /// Prior to this height, a call to [`ChannelManager::claim_funds`] is guaranteed to
433 /// succeed, however you should wait for [`Event::PaymentClaimed`] to be sure.
435 /// [`ChannelManager::claim_funds`]: crate::ln::channelmanager::ChannelManager::claim_funds
436 claim_deadline: Option<u32>,
438 /// Indicates a payment has been claimed and we've received money!
440 /// This most likely occurs when [`ChannelManager::claim_funds`] has been called in response
441 /// to an [`Event::PaymentClaimable`]. However, if we previously crashed during a
442 /// [`ChannelManager::claim_funds`] call you may see this event without a corresponding
443 /// [`Event::PaymentClaimable`] event.
446 /// LDK will not stop an inbound payment from being paid multiple times, so multiple
447 /// `PaymentClaimable` events may be generated for the same payment. If you then call
448 /// [`ChannelManager::claim_funds`] twice for the same [`Event::PaymentClaimable`] you may get
449 /// multiple `PaymentClaimed` events.
451 /// [`ChannelManager::claim_funds`]: crate::ln::channelmanager::ChannelManager::claim_funds
453 /// The node that received the payment.
454 /// This is useful to identify payments which were received via [phantom nodes].
455 /// This field will always be filled in when the event was generated by LDK versions
456 /// 0.0.113 and above.
458 /// [phantom nodes]: crate::sign::PhantomKeysManager
459 receiver_node_id: Option<PublicKey>,
460 /// The payment hash of the claimed payment. Note that LDK will not stop you from
461 /// registering duplicate payment hashes for inbound payments.
462 payment_hash: PaymentHash,
463 /// The value, in thousandths of a satoshi, that this payment is for. May be greater than the
466 /// The purpose of the claimed payment, i.e. whether the payment was for an invoice or a
467 /// spontaneous payment.
468 purpose: PaymentPurpose,
470 /// Indicates an outbound payment we made succeeded (i.e. it made it all the way to its target
471 /// and we got back the payment preimage for it).
473 /// Note for MPP payments: in rare cases, this event may be preceded by a `PaymentPathFailed`
474 /// event. In this situation, you SHOULD treat this payment as having succeeded.
476 /// The `payment_id` passed to [`ChannelManager::send_payment`].
478 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
479 payment_id: Option<PaymentId>,
480 /// The preimage to the hash given to ChannelManager::send_payment.
481 /// Note that this serves as a payment receipt, if you wish to have such a thing, you must
482 /// store it somehow!
483 payment_preimage: PaymentPreimage,
484 /// The hash that was given to [`ChannelManager::send_payment`].
486 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
487 payment_hash: PaymentHash,
488 /// The total fee which was spent at intermediate hops in this payment, across all paths.
490 /// Note that, like [`Route::get_total_fees`] this does *not* include any potential
491 /// overpayment to the recipient node.
493 /// If the recipient or an intermediate node misbehaves and gives us free money, this may
494 /// overstate the amount paid, though this is unlikely.
496 /// [`Route::get_total_fees`]: crate::routing::router::Route::get_total_fees
497 fee_paid_msat: Option<u64>,
499 /// Indicates an outbound payment failed. Individual [`Event::PaymentPathFailed`] events
500 /// provide failure information for each path attempt in the payment, including retries.
502 /// This event is provided once there are no further pending HTLCs for the payment and the
503 /// payment is no longer retryable, due either to the [`Retry`] provided or
504 /// [`ChannelManager::abandon_payment`] having been called for the corresponding payment.
506 /// [`Retry`]: crate::ln::channelmanager::Retry
507 /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
509 /// The `payment_id` passed to [`ChannelManager::send_payment`].
511 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
512 payment_id: PaymentId,
513 /// The hash that was given to [`ChannelManager::send_payment`].
515 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
516 payment_hash: PaymentHash,
517 /// The reason the payment failed. This is only `None` for events generated or serialized
518 /// by versions prior to 0.0.115.
519 reason: Option<PaymentFailureReason>,
521 /// Indicates that a path for an outbound payment was successful.
523 /// Always generated after [`Event::PaymentSent`] and thus useful for scoring channels. See
524 /// [`Event::PaymentSent`] for obtaining the payment preimage.
525 PaymentPathSuccessful {
526 /// The `payment_id` passed to [`ChannelManager::send_payment`].
528 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
529 payment_id: PaymentId,
530 /// The hash that was given to [`ChannelManager::send_payment`].
532 /// This will be `Some` for all payments which completed on LDK 0.0.104 or later.
534 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
535 payment_hash: Option<PaymentHash>,
536 /// The payment path that was successful.
538 /// May contain a closed channel if the HTLC sent along the path was fulfilled on chain.
541 /// Indicates an outbound HTLC we sent failed, likely due to an intermediary node being unable to
544 /// Note that this does *not* indicate that all paths for an MPP payment have failed, see
545 /// [`Event::PaymentFailed`].
547 /// See [`ChannelManager::abandon_payment`] for giving up on this payment before its retries have
550 /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
552 /// The `payment_id` passed to [`ChannelManager::send_payment`].
554 /// This will be `Some` for all payment paths which failed on LDK 0.0.103 or later.
556 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
557 /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
558 payment_id: Option<PaymentId>,
559 /// The hash that was given to [`ChannelManager::send_payment`].
561 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
562 payment_hash: PaymentHash,
563 /// Indicates the payment was rejected for some reason by the recipient. This implies that
564 /// the payment has failed, not just the route in question. If this is not set, the payment may
565 /// be retried via a different route.
566 payment_failed_permanently: bool,
567 /// Extra error details based on the failure type. May contain an update that needs to be
568 /// applied to the [`NetworkGraph`].
570 /// [`NetworkGraph`]: crate::routing::gossip::NetworkGraph
571 failure: PathFailure,
572 /// The payment path that failed.
574 /// The channel responsible for the failed payment path.
576 /// Note that for route hints or for the first hop in a path this may be an SCID alias and
577 /// may not refer to a channel in the public network graph. These aliases may also collide
578 /// with channels in the public network graph.
580 /// If this is `Some`, then the corresponding channel should be avoided when the payment is
581 /// retried. May be `None` for older [`Event`] serializations.
582 short_channel_id: Option<u64>,
584 error_code: Option<u16>,
586 error_data: Option<Vec<u8>>,
588 /// Indicates that a probe payment we sent returned successful, i.e., only failed at the destination.
590 /// The id returned by [`ChannelManager::send_probe`].
592 /// [`ChannelManager::send_probe`]: crate::ln::channelmanager::ChannelManager::send_probe
593 payment_id: PaymentId,
594 /// The hash generated by [`ChannelManager::send_probe`].
596 /// [`ChannelManager::send_probe`]: crate::ln::channelmanager::ChannelManager::send_probe
597 payment_hash: PaymentHash,
598 /// The payment path that was successful.
601 /// Indicates that a probe payment we sent failed at an intermediary node on the path.
603 /// The id returned by [`ChannelManager::send_probe`].
605 /// [`ChannelManager::send_probe`]: crate::ln::channelmanager::ChannelManager::send_probe
606 payment_id: PaymentId,
607 /// The hash generated by [`ChannelManager::send_probe`].
609 /// [`ChannelManager::send_probe`]: crate::ln::channelmanager::ChannelManager::send_probe
610 payment_hash: PaymentHash,
611 /// The payment path that failed.
613 /// The channel responsible for the failed probe.
615 /// Note that for route hints or for the first hop in a path this may be an SCID alias and
616 /// may not refer to a channel in the public network graph. These aliases may also collide
617 /// with channels in the public network graph.
618 short_channel_id: Option<u64>,
620 /// Used to indicate that [`ChannelManager::process_pending_htlc_forwards`] should be called at
621 /// a time in the future.
623 /// [`ChannelManager::process_pending_htlc_forwards`]: crate::ln::channelmanager::ChannelManager::process_pending_htlc_forwards
624 PendingHTLCsForwardable {
625 /// The minimum amount of time that should be waited prior to calling
626 /// process_pending_htlc_forwards. To increase the effort required to correlate payments,
627 /// you should wait a random amount of time in roughly the range (now + time_forwardable,
628 /// now + 5*time_forwardable).
629 time_forwardable: Duration,
631 /// Used to indicate that we've intercepted an HTLC forward. This event will only be generated if
632 /// you've encoded an intercept scid in the receiver's invoice route hints using
633 /// [`ChannelManager::get_intercept_scid`] and have set [`UserConfig::accept_intercept_htlcs`].
635 /// [`ChannelManager::forward_intercepted_htlc`] or
636 /// [`ChannelManager::fail_intercepted_htlc`] MUST be called in response to this event. See
637 /// their docs for more information.
639 /// [`ChannelManager::get_intercept_scid`]: crate::ln::channelmanager::ChannelManager::get_intercept_scid
640 /// [`UserConfig::accept_intercept_htlcs`]: crate::util::config::UserConfig::accept_intercept_htlcs
641 /// [`ChannelManager::forward_intercepted_htlc`]: crate::ln::channelmanager::ChannelManager::forward_intercepted_htlc
642 /// [`ChannelManager::fail_intercepted_htlc`]: crate::ln::channelmanager::ChannelManager::fail_intercepted_htlc
644 /// An id to help LDK identify which HTLC is being forwarded or failed.
645 intercept_id: InterceptId,
646 /// The fake scid that was programmed as the next hop's scid, generated using
647 /// [`ChannelManager::get_intercept_scid`].
649 /// [`ChannelManager::get_intercept_scid`]: crate::ln::channelmanager::ChannelManager::get_intercept_scid
650 requested_next_hop_scid: u64,
651 /// The payment hash used for this HTLC.
652 payment_hash: PaymentHash,
653 /// How many msats were received on the inbound edge of this HTLC.
654 inbound_amount_msat: u64,
655 /// How many msats the payer intended to route to the next node. Depending on the reason you are
656 /// intercepting this payment, you might take a fee by forwarding less than this amount.
657 /// Forwarding less than this amount may break compatibility with LDK versions prior to 0.0.116.
659 /// Note that LDK will NOT check that expected fees were factored into this value. You MUST
660 /// check that whatever fee you want has been included here or subtract it as required. Further,
661 /// LDK will not stop you from forwarding more than you received.
662 expected_outbound_amount_msat: u64,
664 /// Used to indicate that an output which you should know how to spend was confirmed on chain
665 /// and is now spendable.
666 /// Such an output will *not* ever be spent by rust-lightning, and are not at risk of your
667 /// counterparty spending them due to some kind of timeout. Thus, you need to store them
668 /// somewhere and spend them when you create on-chain transactions.
670 /// The outputs which you should store as spendable by you.
671 outputs: Vec<SpendableOutputDescriptor>,
673 /// This event is generated when a payment has been successfully forwarded through us and a
674 /// forwarding fee earned.
676 /// The incoming channel between the previous node and us. This is only `None` for events
677 /// generated or serialized by versions prior to 0.0.107.
678 prev_channel_id: Option<[u8; 32]>,
679 /// The outgoing channel between the next node and us. This is only `None` for events
680 /// generated or serialized by versions prior to 0.0.107.
681 next_channel_id: Option<[u8; 32]>,
682 /// The fee, in milli-satoshis, which was earned as a result of the payment.
684 /// Note that if we force-closed the channel over which we forwarded an HTLC while the HTLC
685 /// was pending, the amount the next hop claimed will have been rounded down to the nearest
686 /// whole satoshi. Thus, the fee calculated here may be higher than expected as we still
687 /// claimed the full value in millisatoshis from the source. In this case,
688 /// `claim_from_onchain_tx` will be set.
690 /// If the channel which sent us the payment has been force-closed, we will claim the funds
691 /// via an on-chain transaction. In that case we do not yet know the on-chain transaction
692 /// fees which we will spend and will instead set this to `None`. It is possible duplicate
693 /// `PaymentForwarded` events are generated for the same payment iff `fee_earned_msat` is
695 fee_earned_msat: Option<u64>,
696 /// If this is `true`, the forwarded HTLC was claimed by our counterparty via an on-chain
698 claim_from_onchain_tx: bool,
699 /// The final amount forwarded, in milli-satoshis, after the fee is deducted.
701 /// The caveat described above the `fee_earned_msat` field applies here as well.
702 outbound_amount_forwarded_msat: Option<u64>,
704 /// Used to indicate that a channel with the given `channel_id` is being opened and pending
705 /// confirmation on-chain.
707 /// This event is emitted when the funding transaction has been signed and is broadcast to the
708 /// network. For 0conf channels it will be immediately followed by the corresponding
709 /// [`Event::ChannelReady`] event.
711 /// The `channel_id` of the channel that is pending confirmation.
712 channel_id: [u8; 32],
713 /// The `user_channel_id` value passed in to [`ChannelManager::create_channel`] for outbound
714 /// channels, or to [`ChannelManager::accept_inbound_channel`] for inbound channels if
715 /// [`UserConfig::manually_accept_inbound_channels`] config flag is set to true. Otherwise
716 /// `user_channel_id` will be randomized for an inbound channel.
718 /// [`ChannelManager::create_channel`]: crate::ln::channelmanager::ChannelManager::create_channel
719 /// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
720 /// [`UserConfig::manually_accept_inbound_channels`]: crate::util::config::UserConfig::manually_accept_inbound_channels
721 user_channel_id: u128,
722 /// The `temporary_channel_id` this channel used to be known by during channel establishment.
724 /// Will be `None` for channels created prior to LDK version 0.0.115.
725 former_temporary_channel_id: Option<[u8; 32]>,
726 /// The `node_id` of the channel counterparty.
727 counterparty_node_id: PublicKey,
728 /// The outpoint of the channel's funding transaction.
729 funding_txo: OutPoint,
731 /// Used to indicate that a channel with the given `channel_id` is ready to
732 /// be used. This event is emitted either when the funding transaction has been confirmed
733 /// on-chain, or, in case of a 0conf channel, when both parties have confirmed the channel
736 /// The `channel_id` of the channel that is ready.
737 channel_id: [u8; 32],
738 /// The `user_channel_id` value passed in to [`ChannelManager::create_channel`] for outbound
739 /// channels, or to [`ChannelManager::accept_inbound_channel`] for inbound channels if
740 /// [`UserConfig::manually_accept_inbound_channels`] config flag is set to true. Otherwise
741 /// `user_channel_id` will be randomized for an inbound channel.
743 /// [`ChannelManager::create_channel`]: crate::ln::channelmanager::ChannelManager::create_channel
744 /// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
745 /// [`UserConfig::manually_accept_inbound_channels`]: crate::util::config::UserConfig::manually_accept_inbound_channels
746 user_channel_id: u128,
747 /// The `node_id` of the channel counterparty.
748 counterparty_node_id: PublicKey,
749 /// The features that this channel will operate with.
750 channel_type: ChannelTypeFeatures,
752 /// Used to indicate that a previously opened channel with the given `channel_id` is in the
753 /// process of closure.
755 /// The `channel_id` of the channel which has been closed. Note that on-chain transactions
756 /// resolving the channel are likely still awaiting confirmation.
757 channel_id: [u8; 32],
758 /// The `user_channel_id` value passed in to [`ChannelManager::create_channel`] for outbound
759 /// channels, or to [`ChannelManager::accept_inbound_channel`] for inbound channels if
760 /// [`UserConfig::manually_accept_inbound_channels`] config flag is set to true. Otherwise
761 /// `user_channel_id` will be randomized for inbound channels.
762 /// This may be zero for inbound channels serialized prior to 0.0.113 and will always be
763 /// zero for objects serialized with LDK versions prior to 0.0.102.
765 /// [`ChannelManager::create_channel`]: crate::ln::channelmanager::ChannelManager::create_channel
766 /// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
767 /// [`UserConfig::manually_accept_inbound_channels`]: crate::util::config::UserConfig::manually_accept_inbound_channels
768 user_channel_id: u128,
769 /// The reason the channel was closed.
770 reason: ClosureReason,
771 /// Counterparty in the closed channel.
773 /// This field will be `None` for objects serialized prior to LDK 0.0.117.
774 counterparty_node_id: Option<PublicKey>,
775 /// Channel capacity of the closing channel (sats).
777 /// This field will be `None` for objects serialized prior to LDK 0.0.117.
778 channel_capacity_sats: Option<u64>,
780 /// Used to indicate to the user that they can abandon the funding transaction and recycle the
781 /// inputs for another purpose.
783 /// The channel_id of the channel which has been closed.
784 channel_id: [u8; 32],
785 /// The full transaction received from the user
786 transaction: Transaction
788 /// Indicates a request to open a new channel by a peer.
790 /// To accept the request, call [`ChannelManager::accept_inbound_channel`]. To reject the
791 /// request, call [`ChannelManager::force_close_without_broadcasting_txn`].
793 /// The event is only triggered when a new open channel request is received and the
794 /// [`UserConfig::manually_accept_inbound_channels`] config flag is set to true.
796 /// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
797 /// [`ChannelManager::force_close_without_broadcasting_txn`]: crate::ln::channelmanager::ChannelManager::force_close_without_broadcasting_txn
798 /// [`UserConfig::manually_accept_inbound_channels`]: crate::util::config::UserConfig::manually_accept_inbound_channels
800 /// The temporary channel ID of the channel requested to be opened.
802 /// When responding to the request, the `temporary_channel_id` should be passed
803 /// back to the ChannelManager through [`ChannelManager::accept_inbound_channel`] to accept,
804 /// or through [`ChannelManager::force_close_without_broadcasting_txn`] to reject.
806 /// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
807 /// [`ChannelManager::force_close_without_broadcasting_txn`]: crate::ln::channelmanager::ChannelManager::force_close_without_broadcasting_txn
808 temporary_channel_id: [u8; 32],
809 /// The node_id of the counterparty requesting to open the channel.
811 /// When responding to the request, the `counterparty_node_id` should be passed
812 /// back to the `ChannelManager` through [`ChannelManager::accept_inbound_channel`] to
813 /// accept the request, or through [`ChannelManager::force_close_without_broadcasting_txn`] to reject the
816 /// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
817 /// [`ChannelManager::force_close_without_broadcasting_txn`]: crate::ln::channelmanager::ChannelManager::force_close_without_broadcasting_txn
818 counterparty_node_id: PublicKey,
819 /// The channel value of the requested channel.
820 funding_satoshis: u64,
821 /// Our starting balance in the channel if the request is accepted, in milli-satoshi.
823 /// The features that this channel will operate with. If you reject the channel, a
824 /// well-behaved counterparty may automatically re-attempt the channel with a new set of
827 /// Note that if [`ChannelTypeFeatures::supports_scid_privacy`] returns true on this type,
828 /// the resulting [`ChannelManager`] will not be readable by versions of LDK prior to
831 /// Furthermore, note that if [`ChannelTypeFeatures::supports_zero_conf`] returns true on this type,
832 /// the resulting [`ChannelManager`] will not be readable by versions of LDK prior to
833 /// 0.0.107. Channels setting this type also need to get manually accepted via
834 /// [`crate::ln::channelmanager::ChannelManager::accept_inbound_channel_from_trusted_peer_0conf`],
835 /// or will be rejected otherwise.
837 /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
838 channel_type: ChannelTypeFeatures,
840 /// Indicates that the HTLC was accepted, but could not be processed when or after attempting to
843 /// Some scenarios where this event may be sent include:
844 /// * Insufficient capacity in the outbound channel
845 /// * While waiting to forward the HTLC, the channel it is meant to be forwarded through closes
846 /// * When an unknown SCID is requested for forwarding a payment.
847 /// * Expected MPP amount has already been reached
848 /// * The HTLC has timed out
850 /// This event, however, does not get generated if an HTLC fails to meet the forwarding
851 /// requirements (i.e. insufficient fees paid, or a CLTV that is too soon).
853 /// The channel over which the HTLC was received.
854 prev_channel_id: [u8; 32],
855 /// Destination of the HTLC that failed to be processed.
856 failed_next_destination: HTLCDestination,
858 /// Indicates that a transaction originating from LDK needs to have its fee bumped. This event
859 /// requires confirmed external funds to be readily available to spend.
861 /// LDK does not currently generate this event unless the
862 /// [`ChannelHandshakeConfig::negotiate_anchors_zero_fee_htlc_tx`] config flag is set to true.
863 /// It is limited to the scope of channels with anchor outputs.
865 /// [`ChannelHandshakeConfig::negotiate_anchors_zero_fee_htlc_tx`]: crate::util::config::ChannelHandshakeConfig::negotiate_anchors_zero_fee_htlc_tx
866 BumpTransaction(BumpTransactionEvent),
869 impl Writeable for Event {
870 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
872 &Event::FundingGenerationReady { .. } => {
874 // We never write out FundingGenerationReady events as, upon disconnection, peers
875 // drop any channels which have not yet exchanged funding_signed.
877 &Event::PaymentClaimable { ref payment_hash, ref amount_msat, counterparty_skimmed_fee_msat,
878 ref purpose, ref receiver_node_id, ref via_channel_id, ref via_user_channel_id,
879 ref claim_deadline, ref onion_fields
882 let mut payment_secret = None;
883 let payment_preimage;
885 PaymentPurpose::InvoicePayment { payment_preimage: preimage, payment_secret: secret } => {
886 payment_secret = Some(secret);
887 payment_preimage = *preimage;
889 PaymentPurpose::SpontaneousPayment(preimage) => {
890 payment_preimage = Some(*preimage);
893 let skimmed_fee_opt = if counterparty_skimmed_fee_msat == 0 { None }
894 else { Some(counterparty_skimmed_fee_msat) };
895 write_tlv_fields!(writer, {
896 (0, payment_hash, required),
897 (1, receiver_node_id, option),
898 (2, payment_secret, option),
899 (3, via_channel_id, option),
900 (4, amount_msat, required),
901 (5, via_user_channel_id, option),
902 // Type 6 was `user_payment_id` on 0.0.103 and earlier
903 (7, claim_deadline, option),
904 (8, payment_preimage, option),
905 (9, onion_fields, option),
906 (10, skimmed_fee_opt, option),
909 &Event::PaymentSent { ref payment_id, ref payment_preimage, ref payment_hash, ref fee_paid_msat } => {
911 write_tlv_fields!(writer, {
912 (0, payment_preimage, required),
913 (1, payment_hash, required),
914 (3, payment_id, option),
915 (5, fee_paid_msat, option),
918 &Event::PaymentPathFailed {
919 ref payment_id, ref payment_hash, ref payment_failed_permanently, ref failure,
920 ref path, ref short_channel_id,
928 error_code.write(writer)?;
930 error_data.write(writer)?;
931 write_tlv_fields!(writer, {
932 (0, payment_hash, required),
933 (1, None::<NetworkUpdate>, option), // network_update in LDK versions prior to 0.0.114
934 (2, payment_failed_permanently, required),
935 (3, false, required), // all_paths_failed in LDK versions prior to 0.0.114
936 (4, path.blinded_tail, option),
937 (5, path.hops, required_vec),
938 (7, short_channel_id, option),
939 (9, None::<RouteParameters>, option), // retry in LDK versions prior to 0.0.115
940 (11, payment_id, option),
941 (13, failure, required),
944 &Event::PendingHTLCsForwardable { time_forwardable: _ } => {
946 // Note that we now ignore these on the read end as we'll re-generate them in
947 // ChannelManager, we write them here only for backwards compatibility.
949 &Event::SpendableOutputs { ref outputs } => {
951 write_tlv_fields!(writer, {
952 (0, WithoutLength(outputs), required),
955 &Event::HTLCIntercepted { requested_next_hop_scid, payment_hash, inbound_amount_msat, expected_outbound_amount_msat, intercept_id } => {
957 let intercept_scid = InterceptNextHop::FakeScid { requested_next_hop_scid };
958 write_tlv_fields!(writer, {
959 (0, intercept_id, required),
960 (2, intercept_scid, required),
961 (4, payment_hash, required),
962 (6, inbound_amount_msat, required),
963 (8, expected_outbound_amount_msat, required),
966 &Event::PaymentForwarded {
967 fee_earned_msat, prev_channel_id, claim_from_onchain_tx,
968 next_channel_id, outbound_amount_forwarded_msat
971 write_tlv_fields!(writer, {
972 (0, fee_earned_msat, option),
973 (1, prev_channel_id, option),
974 (2, claim_from_onchain_tx, required),
975 (3, next_channel_id, option),
976 (5, outbound_amount_forwarded_msat, option),
979 &Event::ChannelClosed { ref channel_id, ref user_channel_id, ref reason,
980 ref counterparty_node_id, ref channel_capacity_sats
983 // `user_channel_id` used to be a single u64 value. In order to remain backwards
984 // compatible with versions prior to 0.0.113, the u128 is serialized as two
985 // separate u64 values.
986 let user_channel_id_low = *user_channel_id as u64;
987 let user_channel_id_high = (*user_channel_id >> 64) as u64;
988 write_tlv_fields!(writer, {
989 (0, channel_id, required),
990 (1, user_channel_id_low, required),
991 (2, reason, required),
992 (3, user_channel_id_high, required),
993 (5, counterparty_node_id, option),
994 (7, channel_capacity_sats, option),
997 &Event::DiscardFunding { ref channel_id, ref transaction } => {
999 write_tlv_fields!(writer, {
1000 (0, channel_id, required),
1001 (2, transaction, required)
1004 &Event::PaymentPathSuccessful { ref payment_id, ref payment_hash, ref path } => {
1005 13u8.write(writer)?;
1006 write_tlv_fields!(writer, {
1007 (0, payment_id, required),
1008 (2, payment_hash, option),
1009 (4, path.hops, required_vec),
1010 (6, path.blinded_tail, option),
1013 &Event::PaymentFailed { ref payment_id, ref payment_hash, ref reason } => {
1014 15u8.write(writer)?;
1015 write_tlv_fields!(writer, {
1016 (0, payment_id, required),
1017 (1, reason, option),
1018 (2, payment_hash, required),
1021 &Event::OpenChannelRequest { .. } => {
1022 17u8.write(writer)?;
1023 // We never write the OpenChannelRequest events as, upon disconnection, peers
1024 // drop any channels which have not yet exchanged funding_signed.
1026 &Event::PaymentClaimed { ref payment_hash, ref amount_msat, ref purpose, ref receiver_node_id } => {
1027 19u8.write(writer)?;
1028 write_tlv_fields!(writer, {
1029 (0, payment_hash, required),
1030 (1, receiver_node_id, option),
1031 (2, purpose, required),
1032 (4, amount_msat, required),
1035 &Event::ProbeSuccessful { ref payment_id, ref payment_hash, ref path } => {
1036 21u8.write(writer)?;
1037 write_tlv_fields!(writer, {
1038 (0, payment_id, required),
1039 (2, payment_hash, required),
1040 (4, path.hops, required_vec),
1041 (6, path.blinded_tail, option),
1044 &Event::ProbeFailed { ref payment_id, ref payment_hash, ref path, ref short_channel_id } => {
1045 23u8.write(writer)?;
1046 write_tlv_fields!(writer, {
1047 (0, payment_id, required),
1048 (2, payment_hash, required),
1049 (4, path.hops, required_vec),
1050 (6, short_channel_id, option),
1051 (8, path.blinded_tail, option),
1054 &Event::HTLCHandlingFailed { ref prev_channel_id, ref failed_next_destination } => {
1055 25u8.write(writer)?;
1056 write_tlv_fields!(writer, {
1057 (0, prev_channel_id, required),
1058 (2, failed_next_destination, required),
1061 &Event::BumpTransaction(ref event)=> {
1062 27u8.write(writer)?;
1064 // We never write the ChannelClose|HTLCResolution events as they'll be replayed
1065 // upon restarting anyway if they remain unresolved.
1066 BumpTransactionEvent::ChannelClose { .. } => {}
1067 BumpTransactionEvent::HTLCResolution { .. } => {}
1069 write_tlv_fields!(writer, {}); // Write a length field for forwards compat
1071 &Event::ChannelReady { ref channel_id, ref user_channel_id, ref counterparty_node_id, ref channel_type } => {
1072 29u8.write(writer)?;
1073 write_tlv_fields!(writer, {
1074 (0, channel_id, required),
1075 (2, user_channel_id, required),
1076 (4, counterparty_node_id, required),
1077 (6, channel_type, required),
1080 &Event::ChannelPending { ref channel_id, ref user_channel_id, ref former_temporary_channel_id, ref counterparty_node_id, ref funding_txo } => {
1081 31u8.write(writer)?;
1082 write_tlv_fields!(writer, {
1083 (0, channel_id, required),
1084 (2, user_channel_id, required),
1085 (4, former_temporary_channel_id, required),
1086 (6, counterparty_node_id, required),
1087 (8, funding_txo, required),
1090 // Note that, going forward, all new events must only write data inside of
1091 // `write_tlv_fields`. Versions 0.0.101+ will ignore odd-numbered events that write
1092 // data via `write_tlv_fields`.
1097 impl MaybeReadable for Event {
1098 fn read<R: io::Read>(reader: &mut R) -> Result<Option<Self>, msgs::DecodeError> {
1099 match Readable::read(reader)? {
1100 // Note that we do not write a length-prefixed TLV for FundingGenerationReady events,
1101 // unlike all other events, thus we return immediately here.
1105 let mut payment_hash = PaymentHash([0; 32]);
1106 let mut payment_preimage = None;
1107 let mut payment_secret = None;
1108 let mut amount_msat = 0;
1109 let mut counterparty_skimmed_fee_msat_opt = None;
1110 let mut receiver_node_id = None;
1111 let mut _user_payment_id = None::<u64>; // Used in 0.0.103 and earlier, no longer written in 0.0.116+.
1112 let mut via_channel_id = None;
1113 let mut claim_deadline = None;
1114 let mut via_user_channel_id = None;
1115 let mut onion_fields = None;
1116 read_tlv_fields!(reader, {
1117 (0, payment_hash, required),
1118 (1, receiver_node_id, option),
1119 (2, payment_secret, option),
1120 (3, via_channel_id, option),
1121 (4, amount_msat, required),
1122 (5, via_user_channel_id, option),
1123 (6, _user_payment_id, option),
1124 (7, claim_deadline, option),
1125 (8, payment_preimage, option),
1126 (9, onion_fields, option),
1127 (10, counterparty_skimmed_fee_msat_opt, option),
1129 let purpose = match payment_secret {
1130 Some(secret) => PaymentPurpose::InvoicePayment {
1132 payment_secret: secret
1134 None if payment_preimage.is_some() => PaymentPurpose::SpontaneousPayment(payment_preimage.unwrap()),
1135 None => return Err(msgs::DecodeError::InvalidValue),
1137 Ok(Some(Event::PaymentClaimable {
1141 counterparty_skimmed_fee_msat: counterparty_skimmed_fee_msat_opt.unwrap_or(0),
1144 via_user_channel_id,
1153 let mut payment_preimage = PaymentPreimage([0; 32]);
1154 let mut payment_hash = None;
1155 let mut payment_id = None;
1156 let mut fee_paid_msat = None;
1157 read_tlv_fields!(reader, {
1158 (0, payment_preimage, required),
1159 (1, payment_hash, option),
1160 (3, payment_id, option),
1161 (5, fee_paid_msat, option),
1163 if payment_hash.is_none() {
1164 payment_hash = Some(PaymentHash(Sha256::hash(&payment_preimage.0[..]).into_inner()));
1166 Ok(Some(Event::PaymentSent {
1169 payment_hash: payment_hash.unwrap(),
1178 let error_code = Readable::read(reader)?;
1180 let error_data = Readable::read(reader)?;
1181 let mut payment_hash = PaymentHash([0; 32]);
1182 let mut payment_failed_permanently = false;
1183 let mut network_update = None;
1184 let mut blinded_tail: Option<BlindedTail> = None;
1185 let mut path: Option<Vec<RouteHop>> = Some(vec![]);
1186 let mut short_channel_id = None;
1187 let mut payment_id = None;
1188 let mut failure_opt = None;
1189 read_tlv_fields!(reader, {
1190 (0, payment_hash, required),
1191 (1, network_update, upgradable_option),
1192 (2, payment_failed_permanently, required),
1193 (4, blinded_tail, option),
1194 // Added as a part of LDK 0.0.101 and always filled in since.
1195 // Defaults to an empty Vec, though likely should have been `Option`al.
1196 (5, path, optional_vec),
1197 (7, short_channel_id, option),
1198 (11, payment_id, option),
1199 (13, failure_opt, upgradable_option),
1201 let failure = failure_opt.unwrap_or_else(|| PathFailure::OnPath { network_update });
1202 Ok(Some(Event::PaymentPathFailed {
1205 payment_failed_permanently,
1207 path: Path { hops: path.unwrap(), blinded_tail },
1220 let mut outputs = WithoutLength(Vec::new());
1221 read_tlv_fields!(reader, {
1222 (0, outputs, required),
1224 Ok(Some(Event::SpendableOutputs { outputs: outputs.0 }))
1229 let mut payment_hash = PaymentHash([0; 32]);
1230 let mut intercept_id = InterceptId([0; 32]);
1231 let mut requested_next_hop_scid = InterceptNextHop::FakeScid { requested_next_hop_scid: 0 };
1232 let mut inbound_amount_msat = 0;
1233 let mut expected_outbound_amount_msat = 0;
1234 read_tlv_fields!(reader, {
1235 (0, intercept_id, required),
1236 (2, requested_next_hop_scid, required),
1237 (4, payment_hash, required),
1238 (6, inbound_amount_msat, required),
1239 (8, expected_outbound_amount_msat, required),
1241 let next_scid = match requested_next_hop_scid {
1242 InterceptNextHop::FakeScid { requested_next_hop_scid: scid } => scid
1244 Ok(Some(Event::HTLCIntercepted {
1246 requested_next_hop_scid: next_scid,
1247 inbound_amount_msat,
1248 expected_outbound_amount_msat,
1254 let mut fee_earned_msat = None;
1255 let mut prev_channel_id = None;
1256 let mut claim_from_onchain_tx = false;
1257 let mut next_channel_id = None;
1258 let mut outbound_amount_forwarded_msat = None;
1259 read_tlv_fields!(reader, {
1260 (0, fee_earned_msat, option),
1261 (1, prev_channel_id, option),
1262 (2, claim_from_onchain_tx, required),
1263 (3, next_channel_id, option),
1264 (5, outbound_amount_forwarded_msat, option),
1266 Ok(Some(Event::PaymentForwarded {
1267 fee_earned_msat, prev_channel_id, claim_from_onchain_tx, next_channel_id,
1268 outbound_amount_forwarded_msat
1275 let mut channel_id = [0; 32];
1276 let mut reason = UpgradableRequired(None);
1277 let mut user_channel_id_low_opt: Option<u64> = None;
1278 let mut user_channel_id_high_opt: Option<u64> = None;
1279 let mut counterparty_node_id = None;
1280 let mut channel_capacity_sats = None;
1281 read_tlv_fields!(reader, {
1282 (0, channel_id, required),
1283 (1, user_channel_id_low_opt, option),
1284 (2, reason, upgradable_required),
1285 (3, user_channel_id_high_opt, option),
1286 (5, counterparty_node_id, option),
1287 (7, channel_capacity_sats, option),
1290 // `user_channel_id` used to be a single u64 value. In order to remain
1291 // backwards compatible with versions prior to 0.0.113, the u128 is serialized
1292 // as two separate u64 values.
1293 let user_channel_id = (user_channel_id_low_opt.unwrap_or(0) as u128) +
1294 ((user_channel_id_high_opt.unwrap_or(0) as u128) << 64);
1296 Ok(Some(Event::ChannelClosed { channel_id, user_channel_id, reason: _init_tlv_based_struct_field!(reason, upgradable_required),
1297 counterparty_node_id, channel_capacity_sats }))
1303 let mut channel_id = [0; 32];
1304 let mut transaction = Transaction{ version: 2, lock_time: PackedLockTime::ZERO, input: Vec::new(), output: Vec::new() };
1305 read_tlv_fields!(reader, {
1306 (0, channel_id, required),
1307 (2, transaction, required),
1309 Ok(Some(Event::DiscardFunding { channel_id, transaction } ))
1315 _init_and_read_tlv_fields!(reader, {
1316 (0, payment_id, required),
1317 (2, payment_hash, option),
1318 (4, path, required_vec),
1319 (6, blinded_tail, option),
1321 Ok(Some(Event::PaymentPathSuccessful {
1322 payment_id: payment_id.0.unwrap(),
1324 path: Path { hops: path, blinded_tail },
1331 let mut payment_hash = PaymentHash([0; 32]);
1332 let mut payment_id = PaymentId([0; 32]);
1333 let mut reason = None;
1334 read_tlv_fields!(reader, {
1335 (0, payment_id, required),
1336 (1, reason, upgradable_option),
1337 (2, payment_hash, required),
1339 Ok(Some(Event::PaymentFailed {
1348 // Value 17 is used for `Event::OpenChannelRequest`.
1353 let mut payment_hash = PaymentHash([0; 32]);
1354 let mut purpose = UpgradableRequired(None);
1355 let mut amount_msat = 0;
1356 let mut receiver_node_id = None;
1357 read_tlv_fields!(reader, {
1358 (0, payment_hash, required),
1359 (1, receiver_node_id, option),
1360 (2, purpose, upgradable_required),
1361 (4, amount_msat, required),
1363 Ok(Some(Event::PaymentClaimed {
1366 purpose: _init_tlv_based_struct_field!(purpose, upgradable_required),
1374 _init_and_read_tlv_fields!(reader, {
1375 (0, payment_id, required),
1376 (2, payment_hash, required),
1377 (4, path, required_vec),
1378 (6, blinded_tail, option),
1380 Ok(Some(Event::ProbeSuccessful {
1381 payment_id: payment_id.0.unwrap(),
1382 payment_hash: payment_hash.0.unwrap(),
1383 path: Path { hops: path, blinded_tail },
1390 _init_and_read_tlv_fields!(reader, {
1391 (0, payment_id, required),
1392 (2, payment_hash, required),
1393 (4, path, required_vec),
1394 (6, short_channel_id, option),
1395 (8, blinded_tail, option),
1397 Ok(Some(Event::ProbeFailed {
1398 payment_id: payment_id.0.unwrap(),
1399 payment_hash: payment_hash.0.unwrap(),
1400 path: Path { hops: path, blinded_tail },
1408 let mut prev_channel_id = [0; 32];
1409 let mut failed_next_destination_opt = UpgradableRequired(None);
1410 read_tlv_fields!(reader, {
1411 (0, prev_channel_id, required),
1412 (2, failed_next_destination_opt, upgradable_required),
1414 Ok(Some(Event::HTLCHandlingFailed {
1416 failed_next_destination: _init_tlv_based_struct_field!(failed_next_destination_opt, upgradable_required),
1424 let mut channel_id = [0; 32];
1425 let mut user_channel_id: u128 = 0;
1426 let mut counterparty_node_id = RequiredWrapper(None);
1427 let mut channel_type = RequiredWrapper(None);
1428 read_tlv_fields!(reader, {
1429 (0, channel_id, required),
1430 (2, user_channel_id, required),
1431 (4, counterparty_node_id, required),
1432 (6, channel_type, required),
1435 Ok(Some(Event::ChannelReady {
1438 counterparty_node_id: counterparty_node_id.0.unwrap(),
1439 channel_type: channel_type.0.unwrap()
1446 let mut channel_id = [0; 32];
1447 let mut user_channel_id: u128 = 0;
1448 let mut former_temporary_channel_id = None;
1449 let mut counterparty_node_id = RequiredWrapper(None);
1450 let mut funding_txo = RequiredWrapper(None);
1451 read_tlv_fields!(reader, {
1452 (0, channel_id, required),
1453 (2, user_channel_id, required),
1454 (4, former_temporary_channel_id, required),
1455 (6, counterparty_node_id, required),
1456 (8, funding_txo, required),
1459 Ok(Some(Event::ChannelPending {
1462 former_temporary_channel_id,
1463 counterparty_node_id: counterparty_node_id.0.unwrap(),
1464 funding_txo: funding_txo.0.unwrap()
1469 // Versions prior to 0.0.100 did not ignore odd types, instead returning InvalidValue.
1470 // Version 0.0.100 failed to properly ignore odd types, possibly resulting in corrupt
1472 x if x % 2 == 1 => {
1473 // If the event is of unknown type, assume it was written with `write_tlv_fields`,
1474 // which prefixes the whole thing with a length BigSize. Because the event is
1475 // odd-type unknown, we should treat it as `Ok(None)` even if it has some TLV
1476 // fields that are even. Thus, we avoid using `read_tlv_fields` and simply read
1477 // exactly the number of bytes specified, ignoring them entirely.
1478 let tlv_len: BigSize = Readable::read(reader)?;
1479 FixedLengthReader::new(reader, tlv_len.0)
1480 .eat_remaining().map_err(|_| msgs::DecodeError::ShortRead)?;
1483 _ => Err(msgs::DecodeError::InvalidValue)
1488 /// An event generated by ChannelManager which indicates a message should be sent to a peer (or
1489 /// broadcast to most peers).
1490 /// These events are handled by PeerManager::process_events if you are using a PeerManager.
1491 #[derive(Clone, Debug)]
1492 pub enum MessageSendEvent {
1493 /// Used to indicate that we've accepted a channel open and should send the accept_channel
1494 /// message provided to the given peer.
1496 /// The node_id of the node which should receive this message
1498 /// The message which should be sent.
1499 msg: msgs::AcceptChannel,
1501 /// Used to indicate that we've accepted a V2 channel open and should send the accept_channel2
1502 /// message provided to the given peer.
1503 SendAcceptChannelV2 {
1504 /// The node_id of the node which should receive this message
1506 /// The message which should be sent.
1507 msg: msgs::AcceptChannelV2,
1509 /// Used to indicate that we've initiated a channel open and should send the open_channel
1510 /// message provided to the given peer.
1512 /// The node_id of the node which should receive this message
1514 /// The message which should be sent.
1515 msg: msgs::OpenChannel,
1517 /// Used to indicate that we've initiated a V2 channel open and should send the open_channel2
1518 /// message provided to the given peer.
1520 /// The node_id of the node which should receive this message
1522 /// The message which should be sent.
1523 msg: msgs::OpenChannelV2,
1525 /// Used to indicate that a funding_created message should be sent to the peer with the given node_id.
1526 SendFundingCreated {
1527 /// The node_id of the node which should receive this message
1529 /// The message which should be sent.
1530 msg: msgs::FundingCreated,
1532 /// Used to indicate that a funding_signed message should be sent to the peer with the given node_id.
1534 /// The node_id of the node which should receive this message
1536 /// The message which should be sent.
1537 msg: msgs::FundingSigned,
1539 /// Used to indicate that a tx_add_input message should be sent to the peer with the given node_id.
1541 /// The node_id of the node which should receive this message
1543 /// The message which should be sent.
1544 msg: msgs::TxAddInput,
1546 /// Used to indicate that a tx_add_output message should be sent to the peer with the given node_id.
1548 /// The node_id of the node which should receive this message
1550 /// The message which should be sent.
1551 msg: msgs::TxAddOutput,
1553 /// Used to indicate that a tx_remove_input message should be sent to the peer with the given node_id.
1555 /// The node_id of the node which should receive this message
1557 /// The message which should be sent.
1558 msg: msgs::TxRemoveInput,
1560 /// Used to indicate that a tx_remove_output message should be sent to the peer with the given node_id.
1561 SendTxRemoveOutput {
1562 /// The node_id of the node which should receive this message
1564 /// The message which should be sent.
1565 msg: msgs::TxRemoveOutput,
1567 /// Used to indicate that a tx_complete message should be sent to the peer with the given node_id.
1569 /// The node_id of the node which should receive this message
1571 /// The message which should be sent.
1572 msg: msgs::TxComplete,
1574 /// Used to indicate that a tx_signatures message should be sent to the peer with the given node_id.
1576 /// The node_id of the node which should receive this message
1578 /// The message which should be sent.
1579 msg: msgs::TxSignatures,
1581 /// Used to indicate that a tx_init_rbf message should be sent to the peer with the given node_id.
1583 /// The node_id of the node which should receive this message
1585 /// The message which should be sent.
1586 msg: msgs::TxInitRbf,
1588 /// Used to indicate that a tx_ack_rbf message should be sent to the peer with the given node_id.
1590 /// The node_id of the node which should receive this message
1592 /// The message which should be sent.
1593 msg: msgs::TxAckRbf,
1595 /// Used to indicate that a tx_abort message should be sent to the peer with the given node_id.
1597 /// The node_id of the node which should receive this message
1599 /// The message which should be sent.
1600 msg: msgs::TxAddInput,
1602 /// Used to indicate that a channel_ready message should be sent to the peer with the given node_id.
1604 /// The node_id of the node which should receive these message(s)
1606 /// The channel_ready message which should be sent.
1607 msg: msgs::ChannelReady,
1609 /// Used to indicate that an announcement_signatures message should be sent to the peer with the given node_id.
1610 SendAnnouncementSignatures {
1611 /// The node_id of the node which should receive these message(s)
1613 /// The announcement_signatures message which should be sent.
1614 msg: msgs::AnnouncementSignatures,
1616 /// Used to indicate that a series of HTLC update messages, as well as a commitment_signed
1617 /// message should be sent to the peer with the given node_id.
1619 /// The node_id of the node which should receive these message(s)
1621 /// The update messages which should be sent. ALL messages in the struct should be sent!
1622 updates: msgs::CommitmentUpdate,
1624 /// Used to indicate that a revoke_and_ack message should be sent to the peer with the given node_id.
1626 /// The node_id of the node which should receive this message
1628 /// The message which should be sent.
1629 msg: msgs::RevokeAndACK,
1631 /// Used to indicate that a closing_signed message should be sent to the peer with the given node_id.
1633 /// The node_id of the node which should receive this message
1635 /// The message which should be sent.
1636 msg: msgs::ClosingSigned,
1638 /// Used to indicate that a shutdown message should be sent to the peer with the given node_id.
1640 /// The node_id of the node which should receive this message
1642 /// The message which should be sent.
1643 msg: msgs::Shutdown,
1645 /// Used to indicate that a channel_reestablish message should be sent to the peer with the given node_id.
1646 SendChannelReestablish {
1647 /// The node_id of the node which should receive this message
1649 /// The message which should be sent.
1650 msg: msgs::ChannelReestablish,
1652 /// Used to send a channel_announcement and channel_update to a specific peer, likely on
1653 /// initial connection to ensure our peers know about our channels.
1654 SendChannelAnnouncement {
1655 /// The node_id of the node which should receive this message
1657 /// The channel_announcement which should be sent.
1658 msg: msgs::ChannelAnnouncement,
1659 /// The followup channel_update which should be sent.
1660 update_msg: msgs::ChannelUpdate,
1662 /// Used to indicate that a channel_announcement and channel_update should be broadcast to all
1663 /// peers (except the peer with node_id either msg.contents.node_id_1 or msg.contents.node_id_2).
1665 /// Note that after doing so, you very likely (unless you did so very recently) want to
1666 /// broadcast a node_announcement (e.g. via [`PeerManager::broadcast_node_announcement`]). This
1667 /// ensures that any nodes which see our channel_announcement also have a relevant
1668 /// node_announcement, including relevant feature flags which may be important for routing
1669 /// through or to us.
1671 /// [`PeerManager::broadcast_node_announcement`]: crate::ln::peer_handler::PeerManager::broadcast_node_announcement
1672 BroadcastChannelAnnouncement {
1673 /// The channel_announcement which should be sent.
1674 msg: msgs::ChannelAnnouncement,
1675 /// The followup channel_update which should be sent.
1676 update_msg: Option<msgs::ChannelUpdate>,
1678 /// Used to indicate that a channel_update should be broadcast to all peers.
1679 BroadcastChannelUpdate {
1680 /// The channel_update which should be sent.
1681 msg: msgs::ChannelUpdate,
1683 /// Used to indicate that a node_announcement should be broadcast to all peers.
1684 BroadcastNodeAnnouncement {
1685 /// The node_announcement which should be sent.
1686 msg: msgs::NodeAnnouncement,
1688 /// Used to indicate that a channel_update should be sent to a single peer.
1689 /// In contrast to [`Self::BroadcastChannelUpdate`], this is used when the channel is a
1690 /// private channel and we shouldn't be informing all of our peers of channel parameters.
1692 /// The node_id of the node which should receive this message
1694 /// The channel_update which should be sent.
1695 msg: msgs::ChannelUpdate,
1697 /// Broadcast an error downstream to be handled
1699 /// The node_id of the node which should receive this message
1701 /// The action which should be taken.
1702 action: msgs::ErrorAction
1704 /// Query a peer for channels with funding transaction UTXOs in a block range.
1705 SendChannelRangeQuery {
1706 /// The node_id of this message recipient
1708 /// The query_channel_range which should be sent.
1709 msg: msgs::QueryChannelRange,
1711 /// Request routing gossip messages from a peer for a list of channels identified by
1712 /// their short_channel_ids.
1714 /// The node_id of this message recipient
1716 /// The query_short_channel_ids which should be sent.
1717 msg: msgs::QueryShortChannelIds,
1719 /// Sends a reply to a channel range query. This may be one of several SendReplyChannelRange events
1720 /// emitted during processing of the query.
1721 SendReplyChannelRange {
1722 /// The node_id of this message recipient
1724 /// The reply_channel_range which should be sent.
1725 msg: msgs::ReplyChannelRange,
1727 /// Sends a timestamp filter for inbound gossip. This should be sent on each new connection to
1728 /// enable receiving gossip messages from the peer.
1729 SendGossipTimestampFilter {
1730 /// The node_id of this message recipient
1732 /// The gossip_timestamp_filter which should be sent.
1733 msg: msgs::GossipTimestampFilter,
1737 /// A trait indicating an object may generate message send events
1738 pub trait MessageSendEventsProvider {
1739 /// Gets the list of pending events which were generated by previous actions, clearing the list
1741 fn get_and_clear_pending_msg_events(&self) -> Vec<MessageSendEvent>;
1744 /// A trait indicating an object may generate onion messages to send
1745 pub trait OnionMessageProvider {
1746 /// Gets the next pending onion message for the peer with the given node id.
1747 fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<msgs::OnionMessage>;
1750 /// A trait indicating an object may generate events.
1752 /// Events are processed by passing an [`EventHandler`] to [`process_pending_events`].
1754 /// Implementations of this trait may also feature an async version of event handling, as shown with
1755 /// [`ChannelManager::process_pending_events_async`] and
1756 /// [`ChainMonitor::process_pending_events_async`].
1760 /// When using this trait, [`process_pending_events`] will call [`handle_event`] for each pending
1761 /// event since the last invocation.
1763 /// In order to ensure no [`Event`]s are lost, implementors of this trait will persist [`Event`]s
1764 /// and replay any unhandled events on startup. An [`Event`] is considered handled when
1765 /// [`process_pending_events`] returns, thus handlers MUST fully handle [`Event`]s and persist any
1766 /// relevant changes to disk *before* returning.
1768 /// Further, because an application may crash between an [`Event`] being handled and the
1769 /// implementor of this trait being re-serialized, [`Event`] handling must be idempotent - in
1770 /// effect, [`Event`]s may be replayed.
1772 /// Note, handlers may call back into the provider and thus deadlocking must be avoided. Be sure to
1773 /// consult the provider's documentation on the implication of processing events and how a handler
1774 /// may safely use the provider (e.g., see [`ChannelManager::process_pending_events`] and
1775 /// [`ChainMonitor::process_pending_events`]).
1777 /// (C-not implementable) As there is likely no reason for a user to implement this trait on their
1780 /// [`process_pending_events`]: Self::process_pending_events
1781 /// [`handle_event`]: EventHandler::handle_event
1782 /// [`ChannelManager::process_pending_events`]: crate::ln::channelmanager::ChannelManager#method.process_pending_events
1783 /// [`ChainMonitor::process_pending_events`]: crate::chain::chainmonitor::ChainMonitor#method.process_pending_events
1784 /// [`ChannelManager::process_pending_events_async`]: crate::ln::channelmanager::ChannelManager::process_pending_events_async
1785 /// [`ChainMonitor::process_pending_events_async`]: crate::chain::chainmonitor::ChainMonitor::process_pending_events_async
1786 pub trait EventsProvider {
1787 /// Processes any events generated since the last call using the given event handler.
1789 /// See the trait-level documentation for requirements.
1790 fn process_pending_events<H: Deref>(&self, handler: H) where H::Target: EventHandler;
1793 /// A trait implemented for objects handling events from [`EventsProvider`].
1795 /// An async variation also exists for implementations of [`EventsProvider`] that support async
1796 /// event handling. The async event handler should satisfy the generic bounds: `F:
1797 /// core::future::Future, H: Fn(Event) -> F`.
1798 pub trait EventHandler {
1799 /// Handles the given [`Event`].
1801 /// See [`EventsProvider`] for details that must be considered when implementing this method.
1802 fn handle_event(&self, event: Event);
1805 impl<F> EventHandler for F where F: Fn(Event) {
1806 fn handle_event(&self, event: Event) {
1811 impl<T: EventHandler> EventHandler for Arc<T> {
1812 fn handle_event(&self, event: Event) {
1813 self.deref().handle_event(event)