]> git.bitcoin.ninja Git - rust-lightning/blob - lightning/src/util/events.rs
Merge pull request #1826 from TheBlueMatt/2022-10-idempotency-err
[rust-lightning] / lightning / src / util / events.rs
1 // This file is Copyright its original authors, visible in version control
2 // history.
3 //
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
8 // licenses.
9
10 //! Events are returned from various bits in the library which indicate some action must be taken
11 //! by the client.
12 //!
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
15 //! few other things.
16
17 use crate::chain::keysinterface::SpendableOutputDescriptor;
18 #[cfg(anchors)]
19 use crate::ln::chan_utils::HTLCOutputInCommitment;
20 use crate::ln::channelmanager::PaymentId;
21 use crate::ln::channel::FUNDING_CONF_DEADLINE_BLOCKS;
22 use crate::ln::features::ChannelTypeFeatures;
23 use crate::ln::msgs;
24 use crate::ln::msgs::DecodeError;
25 use crate::ln::{PaymentPreimage, PaymentHash, PaymentSecret};
26 use crate::routing::gossip::NetworkUpdate;
27 use crate::util::ser::{BigSize, FixedLengthReader, Writeable, Writer, MaybeReadable, Readable, WithoutLength, OptionDeserWrapper};
28 use crate::routing::router::{RouteHop, RouteParameters};
29
30 use bitcoin::{PackedLockTime, Transaction};
31 #[cfg(anchors)]
32 use bitcoin::OutPoint;
33 use bitcoin::blockdata::script::Script;
34 use bitcoin::hashes::Hash;
35 use bitcoin::hashes::sha256::Hash as Sha256;
36 use bitcoin::secp256k1::PublicKey;
37 use crate::io;
38 use crate::prelude::*;
39 use core::time::Duration;
40 use core::ops::Deref;
41 use crate::sync::Arc;
42
43 /// Some information provided on receipt of payment depends on whether the payment received is a
44 /// spontaneous payment or a "conventional" lightning payment that's paying an invoice.
45 #[derive(Clone, Debug)]
46 pub enum PaymentPurpose {
47         /// Information for receiving a payment that we generated an invoice for.
48         InvoicePayment {
49                 /// The preimage to the payment_hash, if the payment hash (and secret) were fetched via
50                 /// [`ChannelManager::create_inbound_payment`]. If provided, this can be handed directly to
51                 /// [`ChannelManager::claim_funds`].
52                 ///
53                 /// [`ChannelManager::create_inbound_payment`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment
54                 /// [`ChannelManager::claim_funds`]: crate::ln::channelmanager::ChannelManager::claim_funds
55                 payment_preimage: Option<PaymentPreimage>,
56                 /// The "payment secret". This authenticates the sender to the recipient, preventing a
57                 /// number of deanonymization attacks during the routing process.
58                 /// It is provided here for your reference, however its accuracy is enforced directly by
59                 /// [`ChannelManager`] using the values you previously provided to
60                 /// [`ChannelManager::create_inbound_payment`] or
61                 /// [`ChannelManager::create_inbound_payment_for_hash`].
62                 ///
63                 /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
64                 /// [`ChannelManager::create_inbound_payment`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment
65                 /// [`ChannelManager::create_inbound_payment_for_hash`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment_for_hash
66                 payment_secret: PaymentSecret,
67         },
68         /// Because this is a spontaneous payment, the payer generated their own preimage rather than us
69         /// (the payee) providing a preimage.
70         SpontaneousPayment(PaymentPreimage),
71 }
72
73 impl_writeable_tlv_based_enum!(PaymentPurpose,
74         (0, InvoicePayment) => {
75                 (0, payment_preimage, option),
76                 (2, payment_secret, required),
77         };
78         (2, SpontaneousPayment)
79 );
80
81 #[derive(Clone, Debug, PartialEq, Eq)]
82 /// The reason the channel was closed. See individual variants more details.
83 pub enum ClosureReason {
84         /// Closure generated from receiving a peer error message.
85         ///
86         /// Our counterparty may have broadcasted their latest commitment state, and we have
87         /// as well.
88         CounterpartyForceClosed {
89                 /// The error which the peer sent us.
90                 ///
91                 /// The string should be sanitized before it is used (e.g emitted to logs
92                 /// or printed to stdout). Otherwise, a well crafted error message may exploit
93                 /// a security vulnerability in the terminal emulator or the logging subsystem.
94                 peer_msg: String,
95         },
96         /// Closure generated from [`ChannelManager::force_close_channel`], called by the user.
97         ///
98         /// [`ChannelManager::force_close_channel`]: crate::ln::channelmanager::ChannelManager::force_close_channel.
99         HolderForceClosed,
100         /// The channel was closed after negotiating a cooperative close and we've now broadcasted
101         /// the cooperative close transaction. Note the shutdown may have been initiated by us.
102         //TODO: split between CounterpartyInitiated/LocallyInitiated
103         CooperativeClosure,
104         /// A commitment transaction was confirmed on chain, closing the channel. Most likely this
105         /// commitment transaction came from our counterparty, but it may also have come from
106         /// a copy of our own `ChannelMonitor`.
107         CommitmentTxConfirmed,
108         /// The funding transaction failed to confirm in a timely manner on an inbound channel.
109         FundingTimedOut,
110         /// Closure generated from processing an event, likely a HTLC forward/relay/reception.
111         ProcessingError {
112                 /// A developer-readable error message which we generated.
113                 err: String,
114         },
115         /// The peer disconnected prior to funding completing. In this case the spec mandates that we
116         /// forget the channel entirely - we can attempt again if the peer reconnects.
117         ///
118         /// This includes cases where we restarted prior to funding completion, including prior to the
119         /// initial [`ChannelMonitor`] persistence completing.
120         ///
121         /// In LDK versions prior to 0.0.107 this could also occur if we were unable to connect to the
122         /// peer because of mutual incompatibility between us and our channel counterparty.
123         ///
124         /// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
125         DisconnectedPeer,
126         /// Closure generated from `ChannelManager::read` if the [`ChannelMonitor`] is newer than
127         /// the [`ChannelManager`] deserialized.
128         ///
129         /// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
130         /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
131         OutdatedChannelManager
132 }
133
134 impl core::fmt::Display for ClosureReason {
135         fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
136                 f.write_str("Channel closed because ")?;
137                 match self {
138                         ClosureReason::CounterpartyForceClosed { peer_msg } => {
139                                 f.write_str("counterparty force-closed with message ")?;
140                                 f.write_str(&peer_msg)
141                         },
142                         ClosureReason::HolderForceClosed => f.write_str("user manually force-closed the channel"),
143                         ClosureReason::CooperativeClosure => f.write_str("the channel was cooperatively closed"),
144                         ClosureReason::CommitmentTxConfirmed => f.write_str("commitment or closing transaction was confirmed on chain."),
145                         ClosureReason::FundingTimedOut => write!(f, "funding transaction failed to confirm within {} blocks", FUNDING_CONF_DEADLINE_BLOCKS),
146                         ClosureReason::ProcessingError { err } => {
147                                 f.write_str("of an exception: ")?;
148                                 f.write_str(&err)
149                         },
150                         ClosureReason::DisconnectedPeer => f.write_str("the peer disconnected prior to the channel being funded"),
151                         ClosureReason::OutdatedChannelManager => f.write_str("the ChannelManager read from disk was stale compared to ChannelMonitor(s)"),
152                 }
153         }
154 }
155
156 impl_writeable_tlv_based_enum_upgradable!(ClosureReason,
157         (0, CounterpartyForceClosed) => { (1, peer_msg, required) },
158         (1, FundingTimedOut) => {},
159         (2, HolderForceClosed) => {},
160         (6, CommitmentTxConfirmed) => {},
161         (4, CooperativeClosure) => {},
162         (8, ProcessingError) => { (1, err, required) },
163         (10, DisconnectedPeer) => {},
164         (12, OutdatedChannelManager) => {},
165 );
166
167 /// Intended destination of a failed HTLC as indicated in [`Event::HTLCHandlingFailed`].
168 #[derive(Clone, Debug, PartialEq, Eq)]
169 pub enum HTLCDestination {
170         /// We tried forwarding to a channel but failed to do so. An example of such an instance is when
171         /// there is insufficient capacity in our outbound channel.
172         NextHopChannel {
173                 /// The `node_id` of the next node. For backwards compatibility, this field is
174                 /// marked as optional, versions prior to 0.0.110 may not always be able to provide
175                 /// counterparty node information.
176                 node_id: Option<PublicKey>,
177                 /// The outgoing `channel_id` between us and the next node.
178                 channel_id: [u8; 32],
179         },
180         /// Scenario where we are unsure of the next node to forward the HTLC to.
181         UnknownNextHop {
182                 /// Short channel id we are requesting to forward an HTLC to.
183                 requested_forward_scid: u64,
184         },
185         /// Failure scenario where an HTLC may have been forwarded to be intended for us,
186         /// but is invalid for some reason, so we reject it.
187         ///
188         /// Some of the reasons may include:
189         /// * HTLC Timeouts
190         /// * Expected MPP amount to claim does not equal HTLC total
191         /// * Claimable amount does not match expected amount
192         FailedPayment {
193                 /// The payment hash of the payment we attempted to process.
194                 payment_hash: PaymentHash
195         },
196 }
197
198 impl_writeable_tlv_based_enum_upgradable!(HTLCDestination,
199         (0, NextHopChannel) => {
200                 (0, node_id, required),
201                 (2, channel_id, required),
202         },
203         (2, UnknownNextHop) => {
204                 (0, requested_forward_scid, required),
205         },
206         (4, FailedPayment) => {
207                 (0, payment_hash, required),
208         }
209 );
210
211 #[cfg(anchors)]
212 /// A descriptor used to sign for a commitment transaction's anchor output.
213 #[derive(Clone, Debug)]
214 pub struct AnchorDescriptor {
215         /// A unique identifier used along with `channel_value_satoshis` to re-derive the
216         /// [`InMemorySigner`] required to sign `input`.
217         ///
218         /// [`InMemorySigner`]: crate::chain::keysinterface::InMemorySigner
219         pub channel_keys_id: [u8; 32],
220         /// The value in satoshis of the channel we're attempting to spend the anchor output of. This is
221         /// used along with `channel_keys_id` to re-derive the [`InMemorySigner`] required to sign
222         /// `input`.
223         ///
224         /// [`InMemorySigner`]: crate::chain::keysinterface::InMemorySigner
225         pub channel_value_satoshis: u64,
226         /// The transaction input's outpoint corresponding to the commitment transaction's anchor
227         /// output.
228         pub outpoint: OutPoint,
229 }
230
231 #[cfg(anchors)]
232 /// Represents the different types of transactions, originating from LDK, to be bumped.
233 #[derive(Clone, Debug)]
234 pub enum BumpTransactionEvent {
235         /// Indicates that a channel featuring anchor outputs is to be closed by broadcasting the local
236         /// commitment transaction. Since commitment transactions have a static feerate pre-agreed upon,
237         /// they may need additional fees to be attached through a child transaction using the popular
238         /// [Child-Pays-For-Parent](https://bitcoinops.org/en/topics/cpfp) fee bumping technique. This
239         /// child transaction must include the anchor input described within `anchor_descriptor` along
240         /// with additional inputs to meet the target feerate. Failure to meet the target feerate
241         /// decreases the confirmation odds of the transaction package (which includes the commitment
242         /// and child anchor transactions), possibly resulting in a loss of funds. Once the transaction
243         /// is constructed, it must be fully signed for and broadcasted by the consumer of the event
244         /// along with the `commitment_tx` enclosed. Note that the `commitment_tx` must always be
245         /// broadcast first, as the child anchor transaction depends on it.
246         ///
247         /// The consumer should be able to sign for any of the additional inputs included within the
248         /// child anchor transaction. To sign its anchor input, an [`InMemorySigner`] should be
249         /// re-derived through [`KeysManager::derive_channel_keys`] with the help of
250         /// [`AnchorDescriptor::channel_keys_id`] and [`AnchorDescriptor::channel_value_satoshis`].
251         ///
252         /// It is possible to receive more than one instance of this event if a valid child anchor
253         /// transaction is never broadcast or is but not with a sufficient fee to be mined. Care should
254         /// be taken by the consumer of the event to ensure any future iterations of the child anchor
255         /// transaction adhere to the [Replace-By-Fee
256         /// rules](https://github.com/bitcoin/bitcoin/blob/master/doc/policy/mempool-replacements.md)
257         /// for fee bumps to be accepted into the mempool, and eventually the chain. As the frequency of
258         /// these events is not user-controlled, users may ignore/drop the event if they are no longer
259         /// able to commit external confirmed funds to the child anchor transaction.
260         ///
261         /// The set of `pending_htlcs` on the commitment transaction to be broadcast can be inspected to
262         /// determine whether a significant portion of the channel's funds are allocated to HTLCs,
263         /// enabling users to make their own decisions regarding the importance of the commitment
264         /// transaction's confirmation. Note that this is not required, but simply exists as an option
265         /// for users to override LDK's behavior. On commitments with no HTLCs (indicated by those with
266         /// an empty `pending_htlcs`), confirmation of the commitment transaction can be considered to
267         /// be not urgent.
268         ///
269         /// [`InMemorySigner`]: crate::chain::keysinterface::InMemorySigner
270         /// [`KeysManager::derive_channel_keys`]: crate::chain::keysinterface::KeysManager::derive_channel_keys
271         ChannelClose {
272                 /// The target feerate that the transaction package, which consists of the commitment
273                 /// transaction and the to-be-crafted child anchor transaction, must meet.
274                 package_target_feerate_sat_per_1000_weight: u32,
275                 /// The channel's commitment transaction to bump the fee of. This transaction should be
276                 /// broadcast along with the anchor transaction constructed as a result of consuming this
277                 /// event.
278                 commitment_tx: Transaction,
279                 /// The absolute fee in satoshis of the commitment transaction. This can be used along the
280                 /// with weight of the commitment transaction to determine its feerate.
281                 commitment_tx_fee_satoshis: u64,
282                 /// The descriptor to sign the anchor input of the anchor transaction constructed as a
283                 /// result of consuming this event.
284                 anchor_descriptor: AnchorDescriptor,
285                 /// The set of pending HTLCs on the commitment transaction that need to be resolved once the
286                 /// commitment transaction confirms.
287                 pending_htlcs: Vec<HTLCOutputInCommitment>,
288         },
289 }
290
291 /// An Event which you should probably take some action in response to.
292 ///
293 /// Note that while Writeable and Readable are implemented for Event, you probably shouldn't use
294 /// them directly as they don't round-trip exactly (for example FundingGenerationReady is never
295 /// written as it makes no sense to respond to it after reconnecting to peers).
296 #[derive(Clone, Debug)]
297 pub enum Event {
298         /// Used to indicate that the client should generate a funding transaction with the given
299         /// parameters and then call [`ChannelManager::funding_transaction_generated`].
300         /// Generated in [`ChannelManager`] message handling.
301         /// Note that *all inputs* in the funding transaction must spend SegWit outputs or your
302         /// counterparty can steal your funds!
303         ///
304         /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
305         /// [`ChannelManager::funding_transaction_generated`]: crate::ln::channelmanager::ChannelManager::funding_transaction_generated
306         FundingGenerationReady {
307                 /// The random channel_id we picked which you'll need to pass into
308                 /// [`ChannelManager::funding_transaction_generated`].
309                 ///
310                 /// [`ChannelManager::funding_transaction_generated`]: crate::ln::channelmanager::ChannelManager::funding_transaction_generated
311                 temporary_channel_id: [u8; 32],
312                 /// The counterparty's node_id, which you'll need to pass back into
313                 /// [`ChannelManager::funding_transaction_generated`].
314                 ///
315                 /// [`ChannelManager::funding_transaction_generated`]: crate::ln::channelmanager::ChannelManager::funding_transaction_generated
316                 counterparty_node_id: PublicKey,
317                 /// The value, in satoshis, that the output should have.
318                 channel_value_satoshis: u64,
319                 /// The script which should be used in the transaction output.
320                 output_script: Script,
321                 /// The `user_channel_id` value passed in to [`ChannelManager::create_channel`], or a
322                 /// random value for an inbound channel.
323                 ///
324                 /// [`ChannelManager::create_channel`]: crate::ln::channelmanager::ChannelManager::create_channel
325                 user_channel_id: u128,
326         },
327         /// Indicates we've received (an offer of) money! Just gotta dig out that payment preimage and
328         /// feed it to [`ChannelManager::claim_funds`] to get it....
329         ///
330         /// Note that if the preimage is not known, you should call
331         /// [`ChannelManager::fail_htlc_backwards`] to free up resources for this HTLC and avoid
332         /// network congestion.
333         /// If you fail to call either [`ChannelManager::claim_funds`] or
334         /// [`ChannelManager::fail_htlc_backwards`] within the HTLC's timeout, the HTLC will be
335         /// automatically failed.
336         ///
337         /// # Note
338         /// LDK will not stop an inbound payment from being paid multiple times, so multiple
339         /// `PaymentReceived` events may be generated for the same payment.
340         ///
341         /// [`ChannelManager::claim_funds`]: crate::ln::channelmanager::ChannelManager::claim_funds
342         /// [`ChannelManager::fail_htlc_backwards`]: crate::ln::channelmanager::ChannelManager::fail_htlc_backwards
343         PaymentReceived {
344                 /// The hash for which the preimage should be handed to the ChannelManager. Note that LDK will
345                 /// not stop you from registering duplicate payment hashes for inbound payments.
346                 payment_hash: PaymentHash,
347                 /// The value, in thousandths of a satoshi, that this payment is for.
348                 amount_msat: u64,
349                 /// Information for claiming this received payment, based on whether the purpose of the
350                 /// payment is to pay an invoice or to send a spontaneous payment.
351                 purpose: PaymentPurpose,
352         },
353         /// Indicates a payment has been claimed and we've received money!
354         ///
355         /// This most likely occurs when [`ChannelManager::claim_funds`] has been called in response
356         /// to an [`Event::PaymentReceived`]. However, if we previously crashed during a
357         /// [`ChannelManager::claim_funds`] call you may see this event without a corresponding
358         /// [`Event::PaymentReceived`] event.
359         ///
360         /// # Note
361         /// LDK will not stop an inbound payment from being paid multiple times, so multiple
362         /// `PaymentReceived` events may be generated for the same payment. If you then call
363         /// [`ChannelManager::claim_funds`] twice for the same [`Event::PaymentReceived`] you may get
364         /// multiple `PaymentClaimed` events.
365         ///
366         /// [`ChannelManager::claim_funds`]: crate::ln::channelmanager::ChannelManager::claim_funds
367         PaymentClaimed {
368                 /// The payment hash of the claimed payment. Note that LDK will not stop you from
369                 /// registering duplicate payment hashes for inbound payments.
370                 payment_hash: PaymentHash,
371                 /// The value, in thousandths of a satoshi, that this payment is for.
372                 amount_msat: u64,
373                 /// The purpose of this claimed payment, i.e. whether the payment was for an invoice or a
374                 /// spontaneous payment.
375                 purpose: PaymentPurpose,
376         },
377         /// Indicates an outbound payment we made succeeded (i.e. it made it all the way to its target
378         /// and we got back the payment preimage for it).
379         ///
380         /// Note for MPP payments: in rare cases, this event may be preceded by a `PaymentPathFailed`
381         /// event. In this situation, you SHOULD treat this payment as having succeeded.
382         PaymentSent {
383                 /// The id returned by [`ChannelManager::send_payment`] and used with
384                 /// [`ChannelManager::retry_payment`].
385                 ///
386                 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
387                 /// [`ChannelManager::retry_payment`]: crate::ln::channelmanager::ChannelManager::retry_payment
388                 payment_id: Option<PaymentId>,
389                 /// The preimage to the hash given to ChannelManager::send_payment.
390                 /// Note that this serves as a payment receipt, if you wish to have such a thing, you must
391                 /// store it somehow!
392                 payment_preimage: PaymentPreimage,
393                 /// The hash that was given to [`ChannelManager::send_payment`].
394                 ///
395                 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
396                 payment_hash: PaymentHash,
397                 /// The total fee which was spent at intermediate hops in this payment, across all paths.
398                 ///
399                 /// Note that, like [`Route::get_total_fees`] this does *not* include any potential
400                 /// overpayment to the recipient node.
401                 ///
402                 /// If the recipient or an intermediate node misbehaves and gives us free money, this may
403                 /// overstate the amount paid, though this is unlikely.
404                 ///
405                 /// [`Route::get_total_fees`]: crate::routing::router::Route::get_total_fees
406                 fee_paid_msat: Option<u64>,
407         },
408         /// Indicates an outbound payment failed. Individual [`Event::PaymentPathFailed`] events
409         /// provide failure information for each MPP part in the payment.
410         ///
411         /// This event is provided once there are no further pending HTLCs for the payment and the
412         /// payment is no longer retryable due to [`ChannelManager::abandon_payment`] having been
413         /// called for the corresponding payment.
414         ///
415         /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
416         PaymentFailed {
417                 /// The id returned by [`ChannelManager::send_payment`] and used with
418                 /// [`ChannelManager::retry_payment`] and [`ChannelManager::abandon_payment`].
419                 ///
420                 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
421                 /// [`ChannelManager::retry_payment`]: crate::ln::channelmanager::ChannelManager::retry_payment
422                 /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
423                 payment_id: PaymentId,
424                 /// The hash that was given to [`ChannelManager::send_payment`].
425                 ///
426                 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
427                 payment_hash: PaymentHash,
428         },
429         /// Indicates that a path for an outbound payment was successful.
430         ///
431         /// Always generated after [`Event::PaymentSent`] and thus useful for scoring channels. See
432         /// [`Event::PaymentSent`] for obtaining the payment preimage.
433         PaymentPathSuccessful {
434                 /// The id returned by [`ChannelManager::send_payment`] and used with
435                 /// [`ChannelManager::retry_payment`].
436                 ///
437                 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
438                 /// [`ChannelManager::retry_payment`]: crate::ln::channelmanager::ChannelManager::retry_payment
439                 payment_id: PaymentId,
440                 /// The hash that was given to [`ChannelManager::send_payment`].
441                 ///
442                 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
443                 payment_hash: Option<PaymentHash>,
444                 /// The payment path that was successful.
445                 ///
446                 /// May contain a closed channel if the HTLC sent along the path was fulfilled on chain.
447                 path: Vec<RouteHop>,
448         },
449         /// Indicates an outbound HTLC we sent failed. Probably some intermediary node dropped
450         /// something. You may wish to retry with a different route.
451         ///
452         /// If you have given up retrying this payment and wish to fail it, you MUST call
453         /// [`ChannelManager::abandon_payment`] at least once for a given [`PaymentId`] or memory
454         /// related to payment tracking will leak.
455         ///
456         /// Note that this does *not* indicate that all paths for an MPP payment have failed, see
457         /// [`Event::PaymentFailed`] and [`all_paths_failed`].
458         ///
459         /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
460         /// [`all_paths_failed`]: Self::PaymentPathFailed::all_paths_failed
461         PaymentPathFailed {
462                 /// The id returned by [`ChannelManager::send_payment`] and used with
463                 /// [`ChannelManager::retry_payment`] and [`ChannelManager::abandon_payment`].
464                 ///
465                 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
466                 /// [`ChannelManager::retry_payment`]: crate::ln::channelmanager::ChannelManager::retry_payment
467                 /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
468                 payment_id: Option<PaymentId>,
469                 /// The hash that was given to [`ChannelManager::send_payment`].
470                 ///
471                 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
472                 payment_hash: PaymentHash,
473                 /// Indicates the payment was rejected for some reason by the recipient. This implies that
474                 /// the payment has failed, not just the route in question. If this is not set, you may
475                 /// retry the payment via a different route.
476                 payment_failed_permanently: bool,
477                 /// Any failure information conveyed via the Onion return packet by a node along the failed
478                 /// payment route.
479                 ///
480                 /// Should be applied to the [`NetworkGraph`] so that routing decisions can take into
481                 /// account the update.
482                 ///
483                 /// [`NetworkGraph`]: crate::routing::gossip::NetworkGraph
484                 network_update: Option<NetworkUpdate>,
485                 /// For both single-path and multi-path payments, this is set if all paths of the payment have
486                 /// failed. This will be set to false if (1) this is an MPP payment and (2) other parts of the
487                 /// larger MPP payment were still in flight when this event was generated.
488                 ///
489                 /// Note that if you are retrying individual MPP parts, using this value to determine if a
490                 /// payment has fully failed is race-y. Because multiple failures can happen prior to events
491                 /// being processed, you may retry in response to a first failure, with a second failure
492                 /// (with `all_paths_failed` set) still pending. Then, when the second failure is processed
493                 /// you will see `all_paths_failed` set even though the retry of the first failure still
494                 /// has an associated in-flight HTLC. See (1) for an example of such a failure.
495                 ///
496                 /// If you wish to retry individual MPP parts and learn when a payment has failed, you must
497                 /// call [`ChannelManager::abandon_payment`] and wait for a [`Event::PaymentFailed`] event.
498                 ///
499                 /// (1) <https://github.com/lightningdevkit/rust-lightning/issues/1164>
500                 ///
501                 /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
502                 all_paths_failed: bool,
503                 /// The payment path that failed.
504                 path: Vec<RouteHop>,
505                 /// The channel responsible for the failed payment path.
506                 ///
507                 /// Note that for route hints or for the first hop in a path this may be an SCID alias and
508                 /// may not refer to a channel in the public network graph. These aliases may also collide
509                 /// with channels in the public network graph.
510                 ///
511                 /// If this is `Some`, then the corresponding channel should be avoided when the payment is
512                 /// retried. May be `None` for older [`Event`] serializations.
513                 short_channel_id: Option<u64>,
514                 /// Parameters needed to compute a new [`Route`] when retrying the failed payment path.
515                 ///
516                 /// See [`find_route`] for details.
517                 ///
518                 /// [`Route`]: crate::routing::router::Route
519                 /// [`find_route`]: crate::routing::router::find_route
520                 retry: Option<RouteParameters>,
521 #[cfg(test)]
522                 error_code: Option<u16>,
523 #[cfg(test)]
524                 error_data: Option<Vec<u8>>,
525         },
526         /// Indicates that a probe payment we sent returned successful, i.e., only failed at the destination.
527         ProbeSuccessful {
528                 /// The id returned by [`ChannelManager::send_probe`].
529                 ///
530                 /// [`ChannelManager::send_probe`]: crate::ln::channelmanager::ChannelManager::send_probe
531                 payment_id: PaymentId,
532                 /// The hash generated by [`ChannelManager::send_probe`].
533                 ///
534                 /// [`ChannelManager::send_probe`]: crate::ln::channelmanager::ChannelManager::send_probe
535                 payment_hash: PaymentHash,
536                 /// The payment path that was successful.
537                 path: Vec<RouteHop>,
538         },
539         /// Indicates that a probe payment we sent failed at an intermediary node on the path.
540         ProbeFailed {
541                 /// The id returned by [`ChannelManager::send_probe`].
542                 ///
543                 /// [`ChannelManager::send_probe`]: crate::ln::channelmanager::ChannelManager::send_probe
544                 payment_id: PaymentId,
545                 /// The hash generated by [`ChannelManager::send_probe`].
546                 ///
547                 /// [`ChannelManager::send_probe`]: crate::ln::channelmanager::ChannelManager::send_probe
548                 payment_hash: PaymentHash,
549                 /// The payment path that failed.
550                 path: Vec<RouteHop>,
551                 /// The channel responsible for the failed probe.
552                 ///
553                 /// Note that for route hints or for the first hop in a path this may be an SCID alias and
554                 /// may not refer to a channel in the public network graph. These aliases may also collide
555                 /// with channels in the public network graph.
556                 short_channel_id: Option<u64>,
557         },
558         /// Used to indicate that [`ChannelManager::process_pending_htlc_forwards`] should be called at
559         /// a time in the future.
560         ///
561         /// [`ChannelManager::process_pending_htlc_forwards`]: crate::ln::channelmanager::ChannelManager::process_pending_htlc_forwards
562         PendingHTLCsForwardable {
563                 /// The minimum amount of time that should be waited prior to calling
564                 /// process_pending_htlc_forwards. To increase the effort required to correlate payments,
565                 /// you should wait a random amount of time in roughly the range (now + time_forwardable,
566                 /// now + 5*time_forwardable).
567                 time_forwardable: Duration,
568         },
569         /// Used to indicate that an output which you should know how to spend was confirmed on chain
570         /// and is now spendable.
571         /// Such an output will *not* ever be spent by rust-lightning, and are not at risk of your
572         /// counterparty spending them due to some kind of timeout. Thus, you need to store them
573         /// somewhere and spend them when you create on-chain transactions.
574         SpendableOutputs {
575                 /// The outputs which you should store as spendable by you.
576                 outputs: Vec<SpendableOutputDescriptor>,
577         },
578         /// This event is generated when a payment has been successfully forwarded through us and a
579         /// forwarding fee earned.
580         PaymentForwarded {
581                 /// The incoming channel between the previous node and us. This is only `None` for events
582                 /// generated or serialized by versions prior to 0.0.107.
583                 prev_channel_id: Option<[u8; 32]>,
584                 /// The outgoing channel between the next node and us. This is only `None` for events
585                 /// generated or serialized by versions prior to 0.0.107.
586                 next_channel_id: Option<[u8; 32]>,
587                 /// The fee, in milli-satoshis, which was earned as a result of the payment.
588                 ///
589                 /// Note that if we force-closed the channel over which we forwarded an HTLC while the HTLC
590                 /// was pending, the amount the next hop claimed will have been rounded down to the nearest
591                 /// whole satoshi. Thus, the fee calculated here may be higher than expected as we still
592                 /// claimed the full value in millisatoshis from the source. In this case,
593                 /// `claim_from_onchain_tx` will be set.
594                 ///
595                 /// If the channel which sent us the payment has been force-closed, we will claim the funds
596                 /// via an on-chain transaction. In that case we do not yet know the on-chain transaction
597                 /// fees which we will spend and will instead set this to `None`. It is possible duplicate
598                 /// `PaymentForwarded` events are generated for the same payment iff `fee_earned_msat` is
599                 /// `None`.
600                 fee_earned_msat: Option<u64>,
601                 /// If this is `true`, the forwarded HTLC was claimed by our counterparty via an on-chain
602                 /// transaction.
603                 claim_from_onchain_tx: bool,
604         },
605         /// Used to indicate that a channel with the given `channel_id` is ready to
606         /// be used. This event is emitted either when the funding transaction has been confirmed
607         /// on-chain, or, in case of a 0conf channel, when both parties have confirmed the channel
608         /// establishment.
609         ChannelReady {
610                 /// The channel_id of the channel that is ready.
611                 channel_id: [u8; 32],
612                 /// The `user_channel_id` value passed in to [`ChannelManager::create_channel`] for outbound
613                 /// channels, or to [`ChannelManager::accept_inbound_channel`] for inbound channels if
614                 /// [`UserConfig::manually_accept_inbound_channels`] config flag is set to true. Otherwise
615                 /// `user_channel_id` will be randomized for an inbound channel.
616                 ///
617                 /// [`ChannelManager::create_channel`]: crate::ln::channelmanager::ChannelManager::create_channel
618                 /// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
619                 /// [`UserConfig::manually_accept_inbound_channels`]: crate::util::config::UserConfig::manually_accept_inbound_channels
620                 user_channel_id: u128,
621                 /// The node_id of the channel counterparty.
622                 counterparty_node_id: PublicKey,
623                 /// The features that this channel will operate with.
624                 channel_type: ChannelTypeFeatures,
625         },
626         /// Used to indicate that a previously opened channel with the given `channel_id` is in the
627         /// process of closure.
628         ChannelClosed  {
629                 /// The channel_id of the channel which has been closed. Note that on-chain transactions
630                 /// resolving the channel are likely still awaiting confirmation.
631                 channel_id: [u8; 32],
632                 /// The `user_channel_id` value passed in to [`ChannelManager::create_channel`] for outbound
633                 /// channels, or to [`ChannelManager::accept_inbound_channel`] for inbound channels if
634                 /// [`UserConfig::manually_accept_inbound_channels`] config flag is set to true. Otherwise
635                 /// `user_channel_id` will be randomized for an inbound channel.
636                 /// This will always be zero for objects serialized with LDK versions prior to 0.0.102.
637                 ///
638                 /// [`ChannelManager::create_channel`]: crate::ln::channelmanager::ChannelManager::create_channel
639                 /// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
640                 /// [`UserConfig::manually_accept_inbound_channels`]: crate::util::config::UserConfig::manually_accept_inbound_channels
641                 user_channel_id: u128,
642                 /// The reason the channel was closed.
643                 reason: ClosureReason
644         },
645         /// Used to indicate to the user that they can abandon the funding transaction and recycle the
646         /// inputs for another purpose.
647         DiscardFunding {
648                 /// The channel_id of the channel which has been closed.
649                 channel_id: [u8; 32],
650                 /// The full transaction received from the user
651                 transaction: Transaction
652         },
653         /// Indicates a request to open a new channel by a peer.
654         ///
655         /// To accept the request, call [`ChannelManager::accept_inbound_channel`]. To reject the
656         /// request, call [`ChannelManager::force_close_without_broadcasting_txn`].
657         ///
658         /// The event is only triggered when a new open channel request is received and the
659         /// [`UserConfig::manually_accept_inbound_channels`] config flag is set to true.
660         ///
661         /// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
662         /// [`ChannelManager::force_close_without_broadcasting_txn`]: crate::ln::channelmanager::ChannelManager::force_close_without_broadcasting_txn
663         /// [`UserConfig::manually_accept_inbound_channels`]: crate::util::config::UserConfig::manually_accept_inbound_channels
664         OpenChannelRequest {
665                 /// The temporary channel ID of the channel requested to be opened.
666                 ///
667                 /// When responding to the request, the `temporary_channel_id` should be passed
668                 /// back to the ChannelManager through [`ChannelManager::accept_inbound_channel`] to accept,
669                 /// or through [`ChannelManager::force_close_without_broadcasting_txn`] to reject.
670                 ///
671                 /// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
672                 /// [`ChannelManager::force_close_without_broadcasting_txn`]: crate::ln::channelmanager::ChannelManager::force_close_without_broadcasting_txn
673                 temporary_channel_id: [u8; 32],
674                 /// The node_id of the counterparty requesting to open the channel.
675                 ///
676                 /// When responding to the request, the `counterparty_node_id` should be passed
677                 /// back to the `ChannelManager` through [`ChannelManager::accept_inbound_channel`] to
678                 /// accept the request, or through [`ChannelManager::force_close_without_broadcasting_txn`] to reject the
679                 /// request.
680                 ///
681                 /// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
682                 /// [`ChannelManager::force_close_without_broadcasting_txn`]: crate::ln::channelmanager::ChannelManager::force_close_without_broadcasting_txn
683                 counterparty_node_id: PublicKey,
684                 /// The channel value of the requested channel.
685                 funding_satoshis: u64,
686                 /// Our starting balance in the channel if the request is accepted, in milli-satoshi.
687                 push_msat: u64,
688                 /// The features that this channel will operate with. If you reject the channel, a
689                 /// well-behaved counterparty may automatically re-attempt the channel with a new set of
690                 /// feature flags.
691                 ///
692                 /// Note that if [`ChannelTypeFeatures::supports_scid_privacy`] returns true on this type,
693                 /// the resulting [`ChannelManager`] will not be readable by versions of LDK prior to
694                 /// 0.0.106.
695                 ///
696                 /// Furthermore, note that if [`ChannelTypeFeatures::supports_zero_conf`] returns true on this type,
697                 /// the resulting [`ChannelManager`] will not be readable by versions of LDK prior to
698                 /// 0.0.107. Channels setting this type also need to get manually accepted via
699                 /// [`crate::ln::channelmanager::ChannelManager::accept_inbound_channel_from_trusted_peer_0conf`],
700                 /// or will be rejected otherwise.
701                 ///
702                 /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
703                 channel_type: ChannelTypeFeatures,
704         },
705         /// Indicates that the HTLC was accepted, but could not be processed when or after attempting to
706         /// forward it.
707         ///
708         /// Some scenarios where this event may be sent include:
709         /// * Insufficient capacity in the outbound channel
710         /// * While waiting to forward the HTLC, the channel it is meant to be forwarded through closes
711         /// * When an unknown SCID is requested for forwarding a payment.
712         /// * Claiming an amount for an MPP payment that exceeds the HTLC total
713         /// * The HTLC has timed out
714         ///
715         /// This event, however, does not get generated if an HTLC fails to meet the forwarding
716         /// requirements (i.e. insufficient fees paid, or a CLTV that is too soon).
717         HTLCHandlingFailed {
718                 /// The channel over which the HTLC was received.
719                 prev_channel_id: [u8; 32],
720                 /// Destination of the HTLC that failed to be processed.
721                 failed_next_destination: HTLCDestination,
722         },
723         #[cfg(anchors)]
724         /// Indicates that a transaction originating from LDK needs to have its fee bumped. This event
725         /// requires confirmed external funds to be readily available to spend.
726         ///
727         /// LDK does not currently generate this event. It is limited to the scope of channels with
728         /// anchor outputs, which will be introduced in a future release.
729         BumpTransaction(BumpTransactionEvent),
730 }
731
732 impl Writeable for Event {
733         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
734                 match self {
735                         &Event::FundingGenerationReady { .. } => {
736                                 0u8.write(writer)?;
737                                 // We never write out FundingGenerationReady events as, upon disconnection, peers
738                                 // drop any channels which have not yet exchanged funding_signed.
739                         },
740                         &Event::PaymentReceived { ref payment_hash, ref amount_msat, ref purpose } => {
741                                 1u8.write(writer)?;
742                                 let mut payment_secret = None;
743                                 let payment_preimage;
744                                 match &purpose {
745                                         PaymentPurpose::InvoicePayment { payment_preimage: preimage, payment_secret: secret } => {
746                                                 payment_secret = Some(secret);
747                                                 payment_preimage = *preimage;
748                                         },
749                                         PaymentPurpose::SpontaneousPayment(preimage) => {
750                                                 payment_preimage = Some(*preimage);
751                                         }
752                                 }
753                                 write_tlv_fields!(writer, {
754                                         (0, payment_hash, required),
755                                         (2, payment_secret, option),
756                                         (4, amount_msat, required),
757                                         (6, 0u64, required), // user_payment_id required for compatibility with 0.0.103 and earlier
758                                         (8, payment_preimage, option),
759                                 });
760                         },
761                         &Event::PaymentSent { ref payment_id, ref payment_preimage, ref payment_hash, ref fee_paid_msat } => {
762                                 2u8.write(writer)?;
763                                 write_tlv_fields!(writer, {
764                                         (0, payment_preimage, required),
765                                         (1, payment_hash, required),
766                                         (3, payment_id, option),
767                                         (5, fee_paid_msat, option),
768                                 });
769                         },
770                         &Event::PaymentPathFailed {
771                                 ref payment_id, ref payment_hash, ref payment_failed_permanently, ref network_update,
772                                 ref all_paths_failed, ref path, ref short_channel_id, ref retry,
773                                 #[cfg(test)]
774                                 ref error_code,
775                                 #[cfg(test)]
776                                 ref error_data,
777                         } => {
778                                 3u8.write(writer)?;
779                                 #[cfg(test)]
780                                 error_code.write(writer)?;
781                                 #[cfg(test)]
782                                 error_data.write(writer)?;
783                                 write_tlv_fields!(writer, {
784                                         (0, payment_hash, required),
785                                         (1, network_update, option),
786                                         (2, payment_failed_permanently, required),
787                                         (3, all_paths_failed, required),
788                                         (5, *path, vec_type),
789                                         (7, short_channel_id, option),
790                                         (9, retry, option),
791                                         (11, payment_id, option),
792                                 });
793                         },
794                         &Event::PendingHTLCsForwardable { time_forwardable: _ } => {
795                                 4u8.write(writer)?;
796                                 // Note that we now ignore these on the read end as we'll re-generate them in
797                                 // ChannelManager, we write them here only for backwards compatibility.
798                         },
799                         &Event::SpendableOutputs { ref outputs } => {
800                                 5u8.write(writer)?;
801                                 write_tlv_fields!(writer, {
802                                         (0, WithoutLength(outputs), required),
803                                 });
804                         },
805                         &Event::PaymentForwarded { fee_earned_msat, prev_channel_id, claim_from_onchain_tx, next_channel_id } => {
806                                 7u8.write(writer)?;
807                                 write_tlv_fields!(writer, {
808                                         (0, fee_earned_msat, option),
809                                         (1, prev_channel_id, option),
810                                         (2, claim_from_onchain_tx, required),
811                                         (3, next_channel_id, option),
812                                 });
813                         },
814                         &Event::ChannelClosed { ref channel_id, ref user_channel_id, ref reason } => {
815                                 9u8.write(writer)?;
816                                 // `user_channel_id` used to be a single u64 value. In order to remain backwards
817                                 // compatible with versions prior to 0.0.113, the u128 is serialized as two
818                                 // separate u64 values.
819                                 let user_channel_id_low = *user_channel_id as u64;
820                                 let user_channel_id_high = (*user_channel_id >> 64) as u64;
821                                 write_tlv_fields!(writer, {
822                                         (0, channel_id, required),
823                                         (1, user_channel_id_low, required),
824                                         (2, reason, required),
825                                         (3, user_channel_id_high, required),
826                                 });
827                         },
828                         &Event::DiscardFunding { ref channel_id, ref transaction } => {
829                                 11u8.write(writer)?;
830                                 write_tlv_fields!(writer, {
831                                         (0, channel_id, required),
832                                         (2, transaction, required)
833                                 })
834                         },
835                         &Event::PaymentPathSuccessful { ref payment_id, ref payment_hash, ref path } => {
836                                 13u8.write(writer)?;
837                                 write_tlv_fields!(writer, {
838                                         (0, payment_id, required),
839                                         (2, payment_hash, option),
840                                         (4, *path, vec_type)
841                                 })
842                         },
843                         &Event::PaymentFailed { ref payment_id, ref payment_hash } => {
844                                 15u8.write(writer)?;
845                                 write_tlv_fields!(writer, {
846                                         (0, payment_id, required),
847                                         (2, payment_hash, required),
848                                 })
849                         },
850                         &Event::OpenChannelRequest { .. } => {
851                                 17u8.write(writer)?;
852                                 // We never write the OpenChannelRequest events as, upon disconnection, peers
853                                 // drop any channels which have not yet exchanged funding_signed.
854                         },
855                         &Event::PaymentClaimed { ref payment_hash, ref amount_msat, ref purpose } => {
856                                 19u8.write(writer)?;
857                                 write_tlv_fields!(writer, {
858                                         (0, payment_hash, required),
859                                         (2, purpose, required),
860                                         (4, amount_msat, required),
861                                 });
862                         },
863                         &Event::ProbeSuccessful { ref payment_id, ref payment_hash, ref path } => {
864                                 21u8.write(writer)?;
865                                 write_tlv_fields!(writer, {
866                                         (0, payment_id, required),
867                                         (2, payment_hash, required),
868                                         (4, *path, vec_type)
869                                 })
870                         },
871                         &Event::ProbeFailed { ref payment_id, ref payment_hash, ref path, ref short_channel_id } => {
872                                 23u8.write(writer)?;
873                                 write_tlv_fields!(writer, {
874                                         (0, payment_id, required),
875                                         (2, payment_hash, required),
876                                         (4, *path, vec_type),
877                                         (6, short_channel_id, option),
878                                 })
879                         },
880                         &Event::HTLCHandlingFailed { ref prev_channel_id, ref failed_next_destination } => {
881                                 25u8.write(writer)?;
882                                 write_tlv_fields!(writer, {
883                                         (0, prev_channel_id, required),
884                                         (2, failed_next_destination, required),
885                                 })
886                         },
887                         #[cfg(anchors)]
888                         &Event::BumpTransaction(ref event)=> {
889                                 27u8.write(writer)?;
890                                 match event {
891                                         // We never write the ChannelClose events as they'll be replayed upon restarting
892                                         // anyway if the commitment transaction remains unconfirmed.
893                                         BumpTransactionEvent::ChannelClose { .. } => {}
894                                 }
895                         }
896                         &Event::ChannelReady { ref channel_id, ref user_channel_id, ref counterparty_node_id, ref channel_type } => {
897                                 29u8.write(writer)?;
898                                 write_tlv_fields!(writer, {
899                                         (0, channel_id, required),
900                                         (2, user_channel_id, required),
901                                         (4, counterparty_node_id, required),
902                                         (6, channel_type, required),
903                                 });
904                         },
905                         // Note that, going forward, all new events must only write data inside of
906                         // `write_tlv_fields`. Versions 0.0.101+ will ignore odd-numbered events that write
907                         // data via `write_tlv_fields`.
908                 }
909                 Ok(())
910         }
911 }
912 impl MaybeReadable for Event {
913         fn read<R: io::Read>(reader: &mut R) -> Result<Option<Self>, msgs::DecodeError> {
914                 match Readable::read(reader)? {
915                         // Note that we do not write a length-prefixed TLV for FundingGenerationReady events,
916                         // unlike all other events, thus we return immediately here.
917                         0u8 => Ok(None),
918                         1u8 => {
919                                 let f = || {
920                                         let mut payment_hash = PaymentHash([0; 32]);
921                                         let mut payment_preimage = None;
922                                         let mut payment_secret = None;
923                                         let mut amount_msat = 0;
924                                         let mut _user_payment_id = None::<u64>; // For compatibility with 0.0.103 and earlier
925                                         read_tlv_fields!(reader, {
926                                                 (0, payment_hash, required),
927                                                 (2, payment_secret, option),
928                                                 (4, amount_msat, required),
929                                                 (6, _user_payment_id, option),
930                                                 (8, payment_preimage, option),
931                                         });
932                                         let purpose = match payment_secret {
933                                                 Some(secret) => PaymentPurpose::InvoicePayment {
934                                                         payment_preimage,
935                                                         payment_secret: secret
936                                                 },
937                                                 None if payment_preimage.is_some() => PaymentPurpose::SpontaneousPayment(payment_preimage.unwrap()),
938                                                 None => return Err(msgs::DecodeError::InvalidValue),
939                                         };
940                                         Ok(Some(Event::PaymentReceived {
941                                                 payment_hash,
942                                                 amount_msat,
943                                                 purpose,
944                                         }))
945                                 };
946                                 f()
947                         },
948                         2u8 => {
949                                 let f = || {
950                                         let mut payment_preimage = PaymentPreimage([0; 32]);
951                                         let mut payment_hash = None;
952                                         let mut payment_id = None;
953                                         let mut fee_paid_msat = None;
954                                         read_tlv_fields!(reader, {
955                                                 (0, payment_preimage, required),
956                                                 (1, payment_hash, option),
957                                                 (3, payment_id, option),
958                                                 (5, fee_paid_msat, option),
959                                         });
960                                         if payment_hash.is_none() {
961                                                 payment_hash = Some(PaymentHash(Sha256::hash(&payment_preimage.0[..]).into_inner()));
962                                         }
963                                         Ok(Some(Event::PaymentSent {
964                                                 payment_id,
965                                                 payment_preimage,
966                                                 payment_hash: payment_hash.unwrap(),
967                                                 fee_paid_msat,
968                                         }))
969                                 };
970                                 f()
971                         },
972                         3u8 => {
973                                 let f = || {
974                                         #[cfg(test)]
975                                         let error_code = Readable::read(reader)?;
976                                         #[cfg(test)]
977                                         let error_data = Readable::read(reader)?;
978                                         let mut payment_hash = PaymentHash([0; 32]);
979                                         let mut payment_failed_permanently = false;
980                                         let mut network_update = None;
981                                         let mut all_paths_failed = Some(true);
982                                         let mut path: Option<Vec<RouteHop>> = Some(vec![]);
983                                         let mut short_channel_id = None;
984                                         let mut retry = None;
985                                         let mut payment_id = None;
986                                         read_tlv_fields!(reader, {
987                                                 (0, payment_hash, required),
988                                                 (1, network_update, ignorable),
989                                                 (2, payment_failed_permanently, required),
990                                                 (3, all_paths_failed, option),
991                                                 (5, path, vec_type),
992                                                 (7, short_channel_id, option),
993                                                 (9, retry, option),
994                                                 (11, payment_id, option),
995                                         });
996                                         Ok(Some(Event::PaymentPathFailed {
997                                                 payment_id,
998                                                 payment_hash,
999                                                 payment_failed_permanently,
1000                                                 network_update,
1001                                                 all_paths_failed: all_paths_failed.unwrap(),
1002                                                 path: path.unwrap(),
1003                                                 short_channel_id,
1004                                                 retry,
1005                                                 #[cfg(test)]
1006                                                 error_code,
1007                                                 #[cfg(test)]
1008                                                 error_data,
1009                                         }))
1010                                 };
1011                                 f()
1012                         },
1013                         4u8 => Ok(None),
1014                         5u8 => {
1015                                 let f = || {
1016                                         let mut outputs = WithoutLength(Vec::new());
1017                                         read_tlv_fields!(reader, {
1018                                                 (0, outputs, required),
1019                                         });
1020                                         Ok(Some(Event::SpendableOutputs { outputs: outputs.0 }))
1021                                 };
1022                                 f()
1023                         },
1024                         7u8 => {
1025                                 let f = || {
1026                                         let mut fee_earned_msat = None;
1027                                         let mut prev_channel_id = None;
1028                                         let mut claim_from_onchain_tx = false;
1029                                         let mut next_channel_id = None;
1030                                         read_tlv_fields!(reader, {
1031                                                 (0, fee_earned_msat, option),
1032                                                 (1, prev_channel_id, option),
1033                                                 (2, claim_from_onchain_tx, required),
1034                                                 (3, next_channel_id, option),
1035                                         });
1036                                         Ok(Some(Event::PaymentForwarded { fee_earned_msat, prev_channel_id, claim_from_onchain_tx, next_channel_id }))
1037                                 };
1038                                 f()
1039                         },
1040                         9u8 => {
1041                                 let f = || {
1042                                         let mut channel_id = [0; 32];
1043                                         let mut reason = None;
1044                                         let mut user_channel_id_low_opt: Option<u64> = None;
1045                                         let mut user_channel_id_high_opt: Option<u64> = None;
1046                                         read_tlv_fields!(reader, {
1047                                                 (0, channel_id, required),
1048                                                 (1, user_channel_id_low_opt, option),
1049                                                 (2, reason, ignorable),
1050                                                 (3, user_channel_id_high_opt, option),
1051                                         });
1052                                         if reason.is_none() { return Ok(None); }
1053
1054                                         // `user_channel_id` used to be a single u64 value. In order to remain
1055                                         // backwards compatible with versions prior to 0.0.113, the u128 is serialized
1056                                         // as two separate u64 values.
1057                                         let user_channel_id = (user_channel_id_low_opt.unwrap_or(0) as u128) +
1058                                                 ((user_channel_id_high_opt.unwrap_or(0) as u128) << 64);
1059
1060                                         Ok(Some(Event::ChannelClosed { channel_id, user_channel_id, reason: reason.unwrap() }))
1061                                 };
1062                                 f()
1063                         },
1064                         11u8 => {
1065                                 let f = || {
1066                                         let mut channel_id = [0; 32];
1067                                         let mut transaction = Transaction{ version: 2, lock_time: PackedLockTime::ZERO, input: Vec::new(), output: Vec::new() };
1068                                         read_tlv_fields!(reader, {
1069                                                 (0, channel_id, required),
1070                                                 (2, transaction, required),
1071                                         });
1072                                         Ok(Some(Event::DiscardFunding { channel_id, transaction } ))
1073                                 };
1074                                 f()
1075                         },
1076                         13u8 => {
1077                                 let f = || {
1078                                         let mut payment_id = PaymentId([0; 32]);
1079                                         let mut payment_hash = None;
1080                                         let mut path: Option<Vec<RouteHop>> = Some(vec![]);
1081                                         read_tlv_fields!(reader, {
1082                                                 (0, payment_id, required),
1083                                                 (2, payment_hash, option),
1084                                                 (4, path, vec_type),
1085                                         });
1086                                         Ok(Some(Event::PaymentPathSuccessful {
1087                                                 payment_id,
1088                                                 payment_hash,
1089                                                 path: path.unwrap(),
1090                                         }))
1091                                 };
1092                                 f()
1093                         },
1094                         15u8 => {
1095                                 let f = || {
1096                                         let mut payment_hash = PaymentHash([0; 32]);
1097                                         let mut payment_id = PaymentId([0; 32]);
1098                                         read_tlv_fields!(reader, {
1099                                                 (0, payment_id, required),
1100                                                 (2, payment_hash, required),
1101                                         });
1102                                         Ok(Some(Event::PaymentFailed {
1103                                                 payment_id,
1104                                                 payment_hash,
1105                                         }))
1106                                 };
1107                                 f()
1108                         },
1109                         17u8 => {
1110                                 // Value 17 is used for `Event::OpenChannelRequest`.
1111                                 Ok(None)
1112                         },
1113                         19u8 => {
1114                                 let f = || {
1115                                         let mut payment_hash = PaymentHash([0; 32]);
1116                                         let mut purpose = None;
1117                                         let mut amount_msat = 0;
1118                                         read_tlv_fields!(reader, {
1119                                                 (0, payment_hash, required),
1120                                                 (2, purpose, ignorable),
1121                                                 (4, amount_msat, required),
1122                                         });
1123                                         if purpose.is_none() { return Ok(None); }
1124                                         Ok(Some(Event::PaymentClaimed {
1125                                                 payment_hash,
1126                                                 purpose: purpose.unwrap(),
1127                                                 amount_msat,
1128                                         }))
1129                                 };
1130                                 f()
1131                         },
1132                         21u8 => {
1133                                 let f = || {
1134                                         let mut payment_id = PaymentId([0; 32]);
1135                                         let mut payment_hash = PaymentHash([0; 32]);
1136                                         let mut path: Option<Vec<RouteHop>> = Some(vec![]);
1137                                         read_tlv_fields!(reader, {
1138                                                 (0, payment_id, required),
1139                                                 (2, payment_hash, required),
1140                                                 (4, path, vec_type),
1141                                         });
1142                                         Ok(Some(Event::ProbeSuccessful {
1143                                                 payment_id,
1144                                                 payment_hash,
1145                                                 path: path.unwrap(),
1146                                         }))
1147                                 };
1148                                 f()
1149                         },
1150                         23u8 => {
1151                                 let f = || {
1152                                         let mut payment_id = PaymentId([0; 32]);
1153                                         let mut payment_hash = PaymentHash([0; 32]);
1154                                         let mut path: Option<Vec<RouteHop>> = Some(vec![]);
1155                                         let mut short_channel_id = None;
1156                                         read_tlv_fields!(reader, {
1157                                                 (0, payment_id, required),
1158                                                 (2, payment_hash, required),
1159                                                 (4, path, vec_type),
1160                                                 (6, short_channel_id, option),
1161                                         });
1162                                         Ok(Some(Event::ProbeFailed {
1163                                                 payment_id,
1164                                                 payment_hash,
1165                                                 path: path.unwrap(),
1166                                                 short_channel_id,
1167                                         }))
1168                                 };
1169                                 f()
1170                         },
1171                         25u8 => {
1172                                 let f = || {
1173                                         let mut prev_channel_id = [0; 32];
1174                                         let mut failed_next_destination_opt = None;
1175                                         read_tlv_fields!(reader, {
1176                                                 (0, prev_channel_id, required),
1177                                                 (2, failed_next_destination_opt, ignorable),
1178                                         });
1179                                         if let Some(failed_next_destination) = failed_next_destination_opt {
1180                                                 Ok(Some(Event::HTLCHandlingFailed {
1181                                                         prev_channel_id,
1182                                                         failed_next_destination,
1183                                                 }))
1184                                         } else {
1185                                                 // If we fail to read a `failed_next_destination` assume it's because
1186                                                 // `MaybeReadable::read` returned `Ok(None)`, though it's also possible we
1187                                                 // were simply missing the field.
1188                                                 Ok(None)
1189                                         }
1190                                 };
1191                                 f()
1192                         },
1193                         27u8 => Ok(None),
1194                         29u8 => {
1195                                 let f = || {
1196                                         let mut channel_id = [0; 32];
1197                                         let mut user_channel_id: u128 = 0;
1198                                         let mut counterparty_node_id = OptionDeserWrapper(None);
1199                                         let mut channel_type = OptionDeserWrapper(None);
1200                                         read_tlv_fields!(reader, {
1201                                                 (0, channel_id, required),
1202                                                 (2, user_channel_id, required),
1203                                                 (4, counterparty_node_id, required),
1204                                                 (6, channel_type, required),
1205                                         });
1206
1207                                         Ok(Some(Event::ChannelReady {
1208                                                 channel_id,
1209                                                 user_channel_id,
1210                                                 counterparty_node_id: counterparty_node_id.0.unwrap(),
1211                                                 channel_type: channel_type.0.unwrap()
1212                                         }))
1213                                 };
1214                                 f()
1215                         },
1216                         // Versions prior to 0.0.100 did not ignore odd types, instead returning InvalidValue.
1217                         // Version 0.0.100 failed to properly ignore odd types, possibly resulting in corrupt
1218                         // reads.
1219                         x if x % 2 == 1 => {
1220                                 // If the event is of unknown type, assume it was written with `write_tlv_fields`,
1221                                 // which prefixes the whole thing with a length BigSize. Because the event is
1222                                 // odd-type unknown, we should treat it as `Ok(None)` even if it has some TLV
1223                                 // fields that are even. Thus, we avoid using `read_tlv_fields` and simply read
1224                                 // exactly the number of bytes specified, ignoring them entirely.
1225                                 let tlv_len: BigSize = Readable::read(reader)?;
1226                                 FixedLengthReader::new(reader, tlv_len.0)
1227                                         .eat_remaining().map_err(|_| msgs::DecodeError::ShortRead)?;
1228                                 Ok(None)
1229                         },
1230                         _ => Err(msgs::DecodeError::InvalidValue)
1231                 }
1232         }
1233 }
1234
1235 /// An event generated by ChannelManager which indicates a message should be sent to a peer (or
1236 /// broadcast to most peers).
1237 /// These events are handled by PeerManager::process_events if you are using a PeerManager.
1238 #[derive(Clone, Debug)]
1239 pub enum MessageSendEvent {
1240         /// Used to indicate that we've accepted a channel open and should send the accept_channel
1241         /// message provided to the given peer.
1242         SendAcceptChannel {
1243                 /// The node_id of the node which should receive this message
1244                 node_id: PublicKey,
1245                 /// The message which should be sent.
1246                 msg: msgs::AcceptChannel,
1247         },
1248         /// Used to indicate that we've initiated a channel open and should send the open_channel
1249         /// message provided to the given peer.
1250         SendOpenChannel {
1251                 /// The node_id of the node which should receive this message
1252                 node_id: PublicKey,
1253                 /// The message which should be sent.
1254                 msg: msgs::OpenChannel,
1255         },
1256         /// Used to indicate that a funding_created message should be sent to the peer with the given node_id.
1257         SendFundingCreated {
1258                 /// The node_id of the node which should receive this message
1259                 node_id: PublicKey,
1260                 /// The message which should be sent.
1261                 msg: msgs::FundingCreated,
1262         },
1263         /// Used to indicate that a funding_signed message should be sent to the peer with the given node_id.
1264         SendFundingSigned {
1265                 /// The node_id of the node which should receive this message
1266                 node_id: PublicKey,
1267                 /// The message which should be sent.
1268                 msg: msgs::FundingSigned,
1269         },
1270         /// Used to indicate that a channel_ready message should be sent to the peer with the given node_id.
1271         SendChannelReady {
1272                 /// The node_id of the node which should receive these message(s)
1273                 node_id: PublicKey,
1274                 /// The channel_ready message which should be sent.
1275                 msg: msgs::ChannelReady,
1276         },
1277         /// Used to indicate that an announcement_signatures message should be sent to the peer with the given node_id.
1278         SendAnnouncementSignatures {
1279                 /// The node_id of the node which should receive these message(s)
1280                 node_id: PublicKey,
1281                 /// The announcement_signatures message which should be sent.
1282                 msg: msgs::AnnouncementSignatures,
1283         },
1284         /// Used to indicate that a series of HTLC update messages, as well as a commitment_signed
1285         /// message should be sent to the peer with the given node_id.
1286         UpdateHTLCs {
1287                 /// The node_id of the node which should receive these message(s)
1288                 node_id: PublicKey,
1289                 /// The update messages which should be sent. ALL messages in the struct should be sent!
1290                 updates: msgs::CommitmentUpdate,
1291         },
1292         /// Used to indicate that a revoke_and_ack message should be sent to the peer with the given node_id.
1293         SendRevokeAndACK {
1294                 /// The node_id of the node which should receive this message
1295                 node_id: PublicKey,
1296                 /// The message which should be sent.
1297                 msg: msgs::RevokeAndACK,
1298         },
1299         /// Used to indicate that a closing_signed message should be sent to the peer with the given node_id.
1300         SendClosingSigned {
1301                 /// The node_id of the node which should receive this message
1302                 node_id: PublicKey,
1303                 /// The message which should be sent.
1304                 msg: msgs::ClosingSigned,
1305         },
1306         /// Used to indicate that a shutdown message should be sent to the peer with the given node_id.
1307         SendShutdown {
1308                 /// The node_id of the node which should receive this message
1309                 node_id: PublicKey,
1310                 /// The message which should be sent.
1311                 msg: msgs::Shutdown,
1312         },
1313         /// Used to indicate that a channel_reestablish message should be sent to the peer with the given node_id.
1314         SendChannelReestablish {
1315                 /// The node_id of the node which should receive this message
1316                 node_id: PublicKey,
1317                 /// The message which should be sent.
1318                 msg: msgs::ChannelReestablish,
1319         },
1320         /// Used to send a channel_announcement and channel_update to a specific peer, likely on
1321         /// initial connection to ensure our peers know about our channels.
1322         SendChannelAnnouncement {
1323                 /// The node_id of the node which should receive this message
1324                 node_id: PublicKey,
1325                 /// The channel_announcement which should be sent.
1326                 msg: msgs::ChannelAnnouncement,
1327                 /// The followup channel_update which should be sent.
1328                 update_msg: msgs::ChannelUpdate,
1329         },
1330         /// Used to indicate that a channel_announcement and channel_update should be broadcast to all
1331         /// peers (except the peer with node_id either msg.contents.node_id_1 or msg.contents.node_id_2).
1332         ///
1333         /// Note that after doing so, you very likely (unless you did so very recently) want to
1334         /// broadcast a node_announcement (e.g. via [`PeerManager::broadcast_node_announcement`]). This
1335         /// ensures that any nodes which see our channel_announcement also have a relevant
1336         /// node_announcement, including relevant feature flags which may be important for routing
1337         /// through or to us.
1338         ///
1339         /// [`PeerManager::broadcast_node_announcement`]: crate::ln::peer_handler::PeerManager::broadcast_node_announcement
1340         BroadcastChannelAnnouncement {
1341                 /// The channel_announcement which should be sent.
1342                 msg: msgs::ChannelAnnouncement,
1343                 /// The followup channel_update which should be sent.
1344                 update_msg: msgs::ChannelUpdate,
1345         },
1346         /// Used to indicate that a channel_update should be broadcast to all peers.
1347         BroadcastChannelUpdate {
1348                 /// The channel_update which should be sent.
1349                 msg: msgs::ChannelUpdate,
1350         },
1351         /// Used to indicate that a channel_update should be sent to a single peer.
1352         /// In contrast to [`Self::BroadcastChannelUpdate`], this is used when the channel is a
1353         /// private channel and we shouldn't be informing all of our peers of channel parameters.
1354         SendChannelUpdate {
1355                 /// The node_id of the node which should receive this message
1356                 node_id: PublicKey,
1357                 /// The channel_update which should be sent.
1358                 msg: msgs::ChannelUpdate,
1359         },
1360         /// Broadcast an error downstream to be handled
1361         HandleError {
1362                 /// The node_id of the node which should receive this message
1363                 node_id: PublicKey,
1364                 /// The action which should be taken.
1365                 action: msgs::ErrorAction
1366         },
1367         /// Query a peer for channels with funding transaction UTXOs in a block range.
1368         SendChannelRangeQuery {
1369                 /// The node_id of this message recipient
1370                 node_id: PublicKey,
1371                 /// The query_channel_range which should be sent.
1372                 msg: msgs::QueryChannelRange,
1373         },
1374         /// Request routing gossip messages from a peer for a list of channels identified by
1375         /// their short_channel_ids.
1376         SendShortIdsQuery {
1377                 /// The node_id of this message recipient
1378                 node_id: PublicKey,
1379                 /// The query_short_channel_ids which should be sent.
1380                 msg: msgs::QueryShortChannelIds,
1381         },
1382         /// Sends a reply to a channel range query. This may be one of several SendReplyChannelRange events
1383         /// emitted during processing of the query.
1384         SendReplyChannelRange {
1385                 /// The node_id of this message recipient
1386                 node_id: PublicKey,
1387                 /// The reply_channel_range which should be sent.
1388                 msg: msgs::ReplyChannelRange,
1389         },
1390         /// Sends a timestamp filter for inbound gossip. This should be sent on each new connection to
1391         /// enable receiving gossip messages from the peer.
1392         SendGossipTimestampFilter {
1393                 /// The node_id of this message recipient
1394                 node_id: PublicKey,
1395                 /// The gossip_timestamp_filter which should be sent.
1396                 msg: msgs::GossipTimestampFilter,
1397         },
1398 }
1399
1400 /// A trait indicating an object may generate message send events
1401 pub trait MessageSendEventsProvider {
1402         /// Gets the list of pending events which were generated by previous actions, clearing the list
1403         /// in the process.
1404         fn get_and_clear_pending_msg_events(&self) -> Vec<MessageSendEvent>;
1405 }
1406
1407 /// A trait indicating an object may generate onion messages to send
1408 pub trait OnionMessageProvider {
1409         /// Gets the next pending onion message for the peer with the given node id.
1410         fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<msgs::OnionMessage>;
1411 }
1412
1413 /// A trait indicating an object may generate events.
1414 ///
1415 /// Events are processed by passing an [`EventHandler`] to [`process_pending_events`].
1416 ///
1417 /// Implementations of this trait may also feature an async version of event handling, as shown with
1418 /// [`ChannelManager::process_pending_events_async`] and
1419 /// [`ChainMonitor::process_pending_events_async`].
1420 ///
1421 /// # Requirements
1422 ///
1423 /// When using this trait, [`process_pending_events`] will call [`handle_event`] for each pending
1424 /// event since the last invocation.
1425 ///
1426 /// In order to ensure no [`Event`]s are lost, implementors of this trait will persist [`Event`]s
1427 /// and replay any unhandled events on startup. An [`Event`] is considered handled when
1428 /// [`process_pending_events`] returns, thus handlers MUST fully handle [`Event`]s and persist any
1429 /// relevant changes to disk *before* returning.
1430 ///
1431 /// Further, because an application may crash between an [`Event`] being handled and the
1432 /// implementor of this trait being re-serialized, [`Event`] handling must be idempotent - in
1433 /// effect, [`Event`]s may be replayed.
1434 ///
1435 /// Note, handlers may call back into the provider and thus deadlocking must be avoided. Be sure to
1436 /// consult the provider's documentation on the implication of processing events and how a handler
1437 /// may safely use the provider (e.g., see [`ChannelManager::process_pending_events`] and
1438 /// [`ChainMonitor::process_pending_events`]).
1439 ///
1440 /// (C-not implementable) As there is likely no reason for a user to implement this trait on their
1441 /// own type(s).
1442 ///
1443 /// [`process_pending_events`]: Self::process_pending_events
1444 /// [`handle_event`]: EventHandler::handle_event
1445 /// [`ChannelManager::process_pending_events`]: crate::ln::channelmanager::ChannelManager#method.process_pending_events
1446 /// [`ChainMonitor::process_pending_events`]: crate::chain::chainmonitor::ChainMonitor#method.process_pending_events
1447 /// [`ChannelManager::process_pending_events_async`]: crate::ln::channelmanager::ChannelManager::process_pending_events_async
1448 /// [`ChainMonitor::process_pending_events_async`]: crate::chain::chainmonitor::ChainMonitor::process_pending_events_async
1449 pub trait EventsProvider {
1450         /// Processes any events generated since the last call using the given event handler.
1451         ///
1452         /// See the trait-level documentation for requirements.
1453         fn process_pending_events<H: Deref>(&self, handler: H) where H::Target: EventHandler;
1454 }
1455
1456 /// A trait implemented for objects handling events from [`EventsProvider`].
1457 ///
1458 /// An async variation also exists for implementations of [`EventsProvider`] that support async
1459 /// event handling. The async event handler should satisfy the generic bounds: `F:
1460 /// core::future::Future, H: Fn(Event) -> F`.
1461 pub trait EventHandler {
1462         /// Handles the given [`Event`].
1463         ///
1464         /// See [`EventsProvider`] for details that must be considered when implementing this method.
1465         fn handle_event(&self, event: Event);
1466 }
1467
1468 impl<F> EventHandler for F where F: Fn(Event) {
1469         fn handle_event(&self, event: Event) {
1470                 self(event)
1471         }
1472 }
1473
1474 impl<T: EventHandler> EventHandler for Arc<T> {
1475         fn handle_event(&self, event: Event) {
1476                 self.deref().handle_event(event)
1477         }
1478 }