_ Git - rust-lightning/blob - lightning/src/events/mod.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 #[cfg(anchors)]
  18 pub mod bump_transaction;
  19
  20 #[cfg(anchors)]
  21 pub use bump_transaction::BumpTransactionEvent;
  22
  23 use crate::chain::keysinterface::SpendableOutputDescriptor;
  24 use crate::ln::channelmanager::{InterceptId, PaymentId};
  25 use crate::ln::channel::FUNDING_CONF_DEADLINE_BLOCKS;
  26 use crate::ln::features::ChannelTypeFeatures;
  27 use crate::ln::msgs;
  28 use crate::ln::{PaymentPreimage, PaymentHash, PaymentSecret};
  29 use crate::routing::gossip::NetworkUpdate;
  30 use crate::util::errors::APIError;
  31 use crate::util::ser::{BigSize, FixedLengthReader, Writeable, Writer, MaybeReadable, Readable, RequiredWrapper, UpgradableRequired, WithoutLength};
  32 use crate::util::string::UntrustedString;
  33 use crate::routing::router::{RouteHop, RouteParameters};
  34
  35 use bitcoin::{PackedLockTime, Transaction};
  36 use bitcoin::blockdata::script::Script;
  37 use bitcoin::hashes::Hash;
  38 use bitcoin::hashes::sha256::Hash as Sha256;
  39 use bitcoin::secp256k1::PublicKey;
  40 use crate::io;
  41 use crate::prelude::*;
  42 use core::time::Duration;
  43 use core::ops::Deref;
  44 use crate::sync::Arc;
  45
  46 /// Some information provided on receipt of payment depends on whether the payment received is a
  47 /// spontaneous payment or a "conventional" lightning payment that's paying an invoice.
  48 #[derive(Clone, Debug, PartialEq, Eq)]
  49 pub enum PaymentPurpose {
  50         /// Information for receiving a payment that we generated an invoice for.
  51         InvoicePayment {
  52                 /// The preimage to the payment_hash, if the payment hash (and secret) were fetched via
  53                 /// [`ChannelManager::create_inbound_payment`]. If provided, this can be handed directly to
  54                 /// [`ChannelManager::claim_funds`].
  55                 ///
  56                 /// [`ChannelManager::create_inbound_payment`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment
  57                 /// [`ChannelManager::claim_funds`]: crate::ln::channelmanager::ChannelManager::claim_funds
  58                 payment_preimage: Option<PaymentPreimage>,
  59                 /// The "payment secret". This authenticates the sender to the recipient, preventing a
  60                 /// number of deanonymization attacks during the routing process.
  61                 /// It is provided here for your reference, however its accuracy is enforced directly by
  62                 /// [`ChannelManager`] using the values you previously provided to
  63                 /// [`ChannelManager::create_inbound_payment`] or
  64                 /// [`ChannelManager::create_inbound_payment_for_hash`].
  65                 ///
  66                 /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
  67                 /// [`ChannelManager::create_inbound_payment`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment
  68                 /// [`ChannelManager::create_inbound_payment_for_hash`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment_for_hash
  69                 payment_secret: PaymentSecret,
  70         },
  71         /// Because this is a spontaneous payment, the payer generated their own preimage rather than us
  72         /// (the payee) providing a preimage.
  73         SpontaneousPayment(PaymentPreimage),
  74 }
  75
  76 impl_writeable_tlv_based_enum!(PaymentPurpose,
  77         (0, InvoicePayment) => {
  78                 (0, payment_preimage, option),
  79                 (2, payment_secret, required),
  80         };
  81         (2, SpontaneousPayment)
  82 );
  83
  84 /// When the payment path failure took place and extra details about it. [`PathFailure::OnPath`] may
  85 /// contain a [`NetworkUpdate`] that needs to be applied to the [`NetworkGraph`].
  86 ///
  87 /// [`NetworkUpdate`]: crate::routing::gossip::NetworkUpdate
  88 /// [`NetworkGraph`]: crate::routing::gossip::NetworkGraph
  89 #[derive(Clone, Debug, Eq, PartialEq)]
  90 pub enum PathFailure {
  91         /// We failed to initially send the payment and no HTLC was committed to. Contains the relevant
  92         /// error.
  93         InitialSend {
  94                 /// The error surfaced from initial send.
  95                 err: APIError,
  96         },
  97         /// A hop on the path failed to forward our payment.
  98         OnPath {
  99                 /// If present, this [`NetworkUpdate`] should be applied to the [`NetworkGraph`] so that routing
 100                 /// decisions can take into account the update.
 101                 ///
 102                 /// [`NetworkUpdate`]: crate::routing::gossip::NetworkUpdate
 103                 /// [`NetworkGraph`]: crate::routing::gossip::NetworkGraph
 104                 network_update: Option<NetworkUpdate>,
 105         },
 106 }
 107
 108 impl_writeable_tlv_based_enum_upgradable!(PathFailure,
 109         (0, OnPath) => {
 110                 (0, network_update, upgradable_option),
 111         },
 112         (2, InitialSend) => {
 113                 (0, err, upgradable_required),
 114         },
 115 );
 116
 117 #[derive(Clone, Debug, PartialEq, Eq)]
 118 /// The reason the channel was closed. See individual variants more details.
 119 pub enum ClosureReason {
 120         /// Closure generated from receiving a peer error message.
 121         ///
 122         /// Our counterparty may have broadcasted their latest commitment state, and we have
 123         /// as well.
 124         CounterpartyForceClosed {
 125                 /// The error which the peer sent us.
 126                 ///
 127                 /// Be careful about printing the peer_msg, a well-crafted message could exploit
 128                 /// a security vulnerability in the terminal emulator or the logging subsystem.
 129                 /// To be safe, use `Display` on `UntrustedString`
 130                 ///
 131                 /// [`UntrustedString`]: crate::util::string::UntrustedString
 132                 peer_msg: UntrustedString,
 133         },
 134         /// Closure generated from [`ChannelManager::force_close_channel`], called by the user.
 135         ///
 136         /// [`ChannelManager::force_close_channel`]: crate::ln::channelmanager::ChannelManager::force_close_channel.
 137         HolderForceClosed,
 138         /// The channel was closed after negotiating a cooperative close and we've now broadcasted
 139         /// the cooperative close transaction. Note the shutdown may have been initiated by us.
 140         //TODO: split between CounterpartyInitiated/LocallyInitiated
 141         CooperativeClosure,
 142         /// A commitment transaction was confirmed on chain, closing the channel. Most likely this
 143         /// commitment transaction came from our counterparty, but it may also have come from
 144         /// a copy of our own `ChannelMonitor`.
 145         CommitmentTxConfirmed,
 146         /// The funding transaction failed to confirm in a timely manner on an inbound channel.
 147         FundingTimedOut,
 148         /// Closure generated from processing an event, likely a HTLC forward/relay/reception.
 149         ProcessingError {
 150                 /// A developer-readable error message which we generated.
 151                 err: String,
 152         },
 153         /// The peer disconnected prior to funding completing. In this case the spec mandates that we
 154         /// forget the channel entirely - we can attempt again if the peer reconnects.
 155         ///
 156         /// This includes cases where we restarted prior to funding completion, including prior to the
 157         /// initial [`ChannelMonitor`] persistence completing.
 158         ///
 159         /// In LDK versions prior to 0.0.107 this could also occur if we were unable to connect to the
 160         /// peer because of mutual incompatibility between us and our channel counterparty.
 161         ///
 162         /// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
 163         DisconnectedPeer,
 164         /// Closure generated from `ChannelManager::read` if the [`ChannelMonitor`] is newer than
 165         /// the [`ChannelManager`] deserialized.
 166         ///
 167         /// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
 168         /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
 169         OutdatedChannelManager
 170 }
 171
 172 impl core::fmt::Display for ClosureReason {
 173         fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
 174                 f.write_str("Channel closed because ")?;
 175                 match self {
 176                         ClosureReason::CounterpartyForceClosed { peer_msg } => {
 177                                 f.write_fmt(format_args!("counterparty force-closed with message: {}", peer_msg))
 178                         },
 179                         ClosureReason::HolderForceClosed => f.write_str("user manually force-closed the channel"),
 180                         ClosureReason::CooperativeClosure => f.write_str("the channel was cooperatively closed"),
 181                         ClosureReason::CommitmentTxConfirmed => f.write_str("commitment or closing transaction was confirmed on chain."),
 182                         ClosureReason::FundingTimedOut => write!(f, "funding transaction failed to confirm within {} blocks", FUNDING_CONF_DEADLINE_BLOCKS),
 183                         ClosureReason::ProcessingError { err } => {
 184                                 f.write_str("of an exception: ")?;
 185                                 f.write_str(&err)
 186                         },
 187                         ClosureReason::DisconnectedPeer => f.write_str("the peer disconnected prior to the channel being funded"),
 188                         ClosureReason::OutdatedChannelManager => f.write_str("the ChannelManager read from disk was stale compared to ChannelMonitor(s)"),
 189                 }
 190         }
 191 }
 192
 193 impl_writeable_tlv_based_enum_upgradable!(ClosureReason,
 194         (0, CounterpartyForceClosed) => { (1, peer_msg, required) },
 195         (1, FundingTimedOut) => {},
 196         (2, HolderForceClosed) => {},
 197         (6, CommitmentTxConfirmed) => {},
 198         (4, CooperativeClosure) => {},
 199         (8, ProcessingError) => { (1, err, required) },
 200         (10, DisconnectedPeer) => {},
 201         (12, OutdatedChannelManager) => {},
 202 );
 203
 204 /// Intended destination of a failed HTLC as indicated in [`Event::HTLCHandlingFailed`].
 205 #[derive(Clone, Debug, PartialEq, Eq)]
 206 pub enum HTLCDestination {
 207         /// We tried forwarding to a channel but failed to do so. An example of such an instance is when
 208         /// there is insufficient capacity in our outbound channel.
 209         NextHopChannel {
 210                 /// The `node_id` of the next node. For backwards compatibility, this field is
 211                 /// marked as optional, versions prior to 0.0.110 may not always be able to provide
 212                 /// counterparty node information.
 213                 node_id: Option<PublicKey>,
 214                 /// The outgoing `channel_id` between us and the next node.
 215                 channel_id: [u8; 32],
 216         },
 217         /// Scenario where we are unsure of the next node to forward the HTLC to.
 218         UnknownNextHop {
 219                 /// Short channel id we are requesting to forward an HTLC to.
 220                 requested_forward_scid: u64,
 221         },
 222         /// We couldn't forward to the outgoing scid. An example would be attempting to send a duplicate
 223         /// intercept HTLC.
 224         InvalidForward {
 225                 /// Short channel id we are requesting to forward an HTLC to.
 226                 requested_forward_scid: u64
 227         },
 228         /// Failure scenario where an HTLC may have been forwarded to be intended for us,
 229         /// but is invalid for some reason, so we reject it.
 230         ///
 231         /// Some of the reasons may include:
 232         /// * HTLC Timeouts
 233         /// * Expected MPP amount has already been reached
 234         /// * Claimable amount does not match expected amount
 235         FailedPayment {
 236                 /// The payment hash of the payment we attempted to process.
 237                 payment_hash: PaymentHash
 238         },
 239 }
 240
 241 impl_writeable_tlv_based_enum_upgradable!(HTLCDestination,
 242         (0, NextHopChannel) => {
 243                 (0, node_id, required),
 244                 (2, channel_id, required),
 245         },
 246         (1, InvalidForward) => {
 247                 (0, requested_forward_scid, required),
 248         },
 249         (2, UnknownNextHop) => {
 250                 (0, requested_forward_scid, required),
 251         },
 252         (4, FailedPayment) => {
 253                 (0, payment_hash, required),
 254         },
 255 );
 256
 257 /// Will be used in [`Event::HTLCIntercepted`] to identify the next hop in the HTLC's path.
 258 /// Currently only used in serialization for the sake of maintaining compatibility. More variants
 259 /// will be added for general-purpose HTLC forward intercepts as well as trampoline forward
 260 /// intercepts in upcoming work.
 261 enum InterceptNextHop {
 262         FakeScid {
 263                 requested_next_hop_scid: u64,
 264         },
 265 }
 266
 267 impl_writeable_tlv_based_enum!(InterceptNextHop,
 268         (0, FakeScid) => {
 269                 (0, requested_next_hop_scid, required),
 270         };
 271 );
 272
 273 /// An Event which you should probably take some action in response to.
 274 ///
 275 /// Note that while Writeable and Readable are implemented for Event, you probably shouldn't use
 276 /// them directly as they don't round-trip exactly (for example FundingGenerationReady is never
 277 /// written as it makes no sense to respond to it after reconnecting to peers).
 278 #[derive(Clone, Debug, PartialEq, Eq)]
 279 pub enum Event {
 280         /// Used to indicate that the client should generate a funding transaction with the given
 281         /// parameters and then call [`ChannelManager::funding_transaction_generated`].
 282         /// Generated in [`ChannelManager`] message handling.
 283         /// Note that *all inputs* in the funding transaction must spend SegWit outputs or your
 284         /// counterparty can steal your funds!
 285         ///
 286         /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
 287         /// [`ChannelManager::funding_transaction_generated`]: crate::ln::channelmanager::ChannelManager::funding_transaction_generated
 288         FundingGenerationReady {
 289                 /// The random channel_id we picked which you'll need to pass into
 290                 /// [`ChannelManager::funding_transaction_generated`].
 291                 ///
 292                 /// [`ChannelManager::funding_transaction_generated`]: crate::ln::channelmanager::ChannelManager::funding_transaction_generated
 293                 temporary_channel_id: [u8; 32],
 294                 /// The counterparty's node_id, which you'll need to pass back into
 295                 /// [`ChannelManager::funding_transaction_generated`].
 296                 ///
 297                 /// [`ChannelManager::funding_transaction_generated`]: crate::ln::channelmanager::ChannelManager::funding_transaction_generated
 298                 counterparty_node_id: PublicKey,
 299                 /// The value, in satoshis, that the output should have.
 300                 channel_value_satoshis: u64,
 301                 /// The script which should be used in the transaction output.
 302                 output_script: Script,
 303                 /// The `user_channel_id` value passed in to [`ChannelManager::create_channel`], or a
 304                 /// random value for an inbound channel. This may be zero for objects serialized with LDK
 305                 /// versions prior to 0.0.113.
 306                 ///
 307                 /// [`ChannelManager::create_channel`]: crate::ln::channelmanager::ChannelManager::create_channel
 308                 user_channel_id: u128,
 309         },
 310         /// Indicates that we've been offered a payment and it needs to be claimed via calling
 311         /// [`ChannelManager::claim_funds`] with the preimage given in [`PaymentPurpose`].
 312         ///
 313         /// Note that if the preimage is not known, you should call
 314         /// [`ChannelManager::fail_htlc_backwards`] or [`ChannelManager::fail_htlc_backwards_with_reason`]
 315         /// to free up resources for this HTLC and avoid network congestion.
 316         /// If you fail to call either [`ChannelManager::claim_funds`], [`ChannelManager::fail_htlc_backwards`],
 317         /// or [`ChannelManager::fail_htlc_backwards_with_reason`] within the HTLC's timeout, the HTLC will be
 318         /// automatically failed.
 319         ///
 320         /// # Note
 321         /// LDK will not stop an inbound payment from being paid multiple times, so multiple
 322         /// `PaymentClaimable` events may be generated for the same payment.
 323         ///
 324         /// # Note
 325         /// This event used to be called `PaymentReceived` in LDK versions 0.0.112 and earlier.
 326         ///
 327         /// [`ChannelManager::claim_funds`]: crate::ln::channelmanager::ChannelManager::claim_funds
 328         /// [`ChannelManager::fail_htlc_backwards`]: crate::ln::channelmanager::ChannelManager::fail_htlc_backwards
 329         /// [`ChannelManager::fail_htlc_backwards_with_reason`]: crate::ln::channelmanager::ChannelManager::fail_htlc_backwards_with_reason
 330         PaymentClaimable {
 331                 /// The node that will receive the payment after it has been claimed.
 332                 /// This is useful to identify payments received via [phantom nodes].
 333                 /// This field will always be filled in when the event was generated by LDK versions
 334                 /// 0.0.113 and above.
 335                 ///
 336                 /// [phantom nodes]: crate::chain::keysinterface::PhantomKeysManager
 337                 receiver_node_id: Option<PublicKey>,
 338                 /// The hash for which the preimage should be handed to the ChannelManager. Note that LDK will
 339                 /// not stop you from registering duplicate payment hashes for inbound payments.
 340                 payment_hash: PaymentHash,
 341                 /// The value, in thousandths of a satoshi, that this payment is for.
 342                 amount_msat: u64,
 343                 /// Information for claiming this received payment, based on whether the purpose of the
 344                 /// payment is to pay an invoice or to send a spontaneous payment.
 345                 purpose: PaymentPurpose,
 346                 /// The `channel_id` indicating over which channel we received the payment.
 347                 via_channel_id: Option<[u8; 32]>,
 348                 /// The `user_channel_id` indicating over which channel we received the payment.
 349                 via_user_channel_id: Option<u128>,
 350         },
 351         /// Indicates a payment has been claimed and we've received money!
 352         ///
 353         /// This most likely occurs when [`ChannelManager::claim_funds`] has been called in response
 354         /// to an [`Event::PaymentClaimable`]. However, if we previously crashed during a
 355         /// [`ChannelManager::claim_funds`] call you may see this event without a corresponding
 356         /// [`Event::PaymentClaimable`] event.
 357         ///
 358         /// # Note
 359         /// LDK will not stop an inbound payment from being paid multiple times, so multiple
 360         /// `PaymentClaimable` events may be generated for the same payment. If you then call
 361         /// [`ChannelManager::claim_funds`] twice for the same [`Event::PaymentClaimable`] you may get
 362         /// multiple `PaymentClaimed` events.
 363         ///
 364         /// [`ChannelManager::claim_funds`]: crate::ln::channelmanager::ChannelManager::claim_funds
 365         PaymentClaimed {
 366                 /// The node that received the payment.
 367                 /// This is useful to identify payments which were received via [phantom nodes].
 368                 /// This field will always be filled in when the event was generated by LDK versions
 369                 /// 0.0.113 and above.
 370                 ///
 371                 /// [phantom nodes]: crate::chain::keysinterface::PhantomKeysManager
 372                 receiver_node_id: Option<PublicKey>,
 373                 /// The payment hash of the claimed payment. Note that LDK will not stop you from
 374                 /// registering duplicate payment hashes for inbound payments.
 375                 payment_hash: PaymentHash,
 376                 /// The value, in thousandths of a satoshi, that this payment is for.
 377                 amount_msat: u64,
 378                 /// The purpose of the claimed payment, i.e. whether the payment was for an invoice or a
 379                 /// spontaneous payment.
 380                 purpose: PaymentPurpose,
 381         },
 382         /// Indicates an outbound payment we made succeeded (i.e. it made it all the way to its target
 383         /// and we got back the payment preimage for it).
 384         ///
 385         /// Note for MPP payments: in rare cases, this event may be preceded by a `PaymentPathFailed`
 386         /// event. In this situation, you SHOULD treat this payment as having succeeded.
 387         PaymentSent {
 388                 /// The id returned by [`ChannelManager::send_payment`].
 389                 ///
 390                 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
 391                 payment_id: Option<PaymentId>,
 392                 /// The preimage to the hash given to ChannelManager::send_payment.
 393                 /// Note that this serves as a payment receipt, if you wish to have such a thing, you must
 394                 /// store it somehow!
 395                 payment_preimage: PaymentPreimage,
 396                 /// The hash that was given to [`ChannelManager::send_payment`].
 397                 ///
 398                 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
 399                 payment_hash: PaymentHash,
 400                 /// The total fee which was spent at intermediate hops in this payment, across all paths.
 401                 ///
 402                 /// Note that, like [`Route::get_total_fees`] this does *not* include any potential
 403                 /// overpayment to the recipient node.
 404                 ///
 405                 /// If the recipient or an intermediate node misbehaves and gives us free money, this may
 406                 /// overstate the amount paid, though this is unlikely.
 407                 ///
 408                 /// [`Route::get_total_fees`]: crate::routing::router::Route::get_total_fees
 409                 fee_paid_msat: Option<u64>,
 410         },
 411         /// Indicates an outbound payment failed. Individual [`Event::PaymentPathFailed`] events
 412         /// provide failure information for each path attempt in the payment, including retries.
 413         ///
 414         /// This event is provided once there are no further pending HTLCs for the payment and the
 415         /// payment is no longer retryable, due either to the [`Retry`] provided or
 416         /// [`ChannelManager::abandon_payment`] having been called for the corresponding payment.
 417         ///
 418         /// [`Retry`]: crate::ln::channelmanager::Retry
 419         /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
 420         PaymentFailed {
 421                 /// The id returned by [`ChannelManager::send_payment`] and used with
 422                 /// [`ChannelManager::abandon_payment`].
 423                 ///
 424                 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
 425                 /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
 426                 payment_id: PaymentId,
 427                 /// The hash that was given to [`ChannelManager::send_payment`].
 428                 ///
 429                 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
 430                 payment_hash: PaymentHash,
 431         },
 432         /// Indicates that a path for an outbound payment was successful.
 433         ///
 434         /// Always generated after [`Event::PaymentSent`] and thus useful for scoring channels. See
 435         /// [`Event::PaymentSent`] for obtaining the payment preimage.
 436         PaymentPathSuccessful {
 437                 /// The id returned by [`ChannelManager::send_payment`].
 438                 ///
 439                 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
 440                 payment_id: PaymentId,
 441                 /// The hash that was given to [`ChannelManager::send_payment`].
 442                 ///
 443                 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
 444                 payment_hash: Option<PaymentHash>,
 445                 /// The payment path that was successful.
 446                 ///
 447                 /// May contain a closed channel if the HTLC sent along the path was fulfilled on chain.
 448                 path: Vec<RouteHop>,
 449         },
 450         /// Indicates an outbound HTLC we sent failed, likely due to an intermediary node being unable to
 451         /// handle the HTLC.
 452         ///
 453         /// Note that this does *not* indicate that all paths for an MPP payment have failed, see
 454         /// [`Event::PaymentFailed`].
 455         ///
 456         /// See [`ChannelManager::abandon_payment`] for giving up on this payment before its retries have
 457         /// been exhausted.
 458         ///
 459         /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
 460         PaymentPathFailed {
 461                 /// The id returned by [`ChannelManager::send_payment`] and used with
 462                 /// [`ChannelManager::abandon_payment`].
 463                 ///
 464                 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
 465                 /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
 466                 payment_id: Option<PaymentId>,
 467                 /// The hash that was given to [`ChannelManager::send_payment`].
 468                 ///
 469                 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
 470                 payment_hash: PaymentHash,
 471                 /// Indicates the payment was rejected for some reason by the recipient. This implies that
 472                 /// the payment has failed, not just the route in question. If this is not set, the payment may
 473                 /// be retried via a different route.
 474                 payment_failed_permanently: bool,
 475                 /// Extra error details based on the failure type. May contain an update that needs to be
 476                 /// applied to the [`NetworkGraph`].
 477                 ///
 478                 /// [`NetworkGraph`]: crate::routing::gossip::NetworkGraph
 479                 failure: PathFailure,
 480                 /// The payment path that failed.
 481                 path: Vec<RouteHop>,
 482                 /// The channel responsible for the failed payment path.
 483                 ///
 484                 /// Note that for route hints or for the first hop in a path this may be an SCID alias and
 485                 /// may not refer to a channel in the public network graph. These aliases may also collide
 486                 /// with channels in the public network graph.
 487                 ///
 488                 /// If this is `Some`, then the corresponding channel should be avoided when the payment is
 489                 /// retried. May be `None` for older [`Event`] serializations.
 490                 short_channel_id: Option<u64>,
 491 #[cfg(test)]
 492                 error_code: Option<u16>,
 493 #[cfg(test)]
 494                 error_data: Option<Vec<u8>>,
 495         },
 496         /// Indicates that a probe payment we sent returned successful, i.e., only failed at the destination.
 497         ProbeSuccessful {
 498                 /// The id returned by [`ChannelManager::send_probe`].
 499                 ///
 500                 /// [`ChannelManager::send_probe`]: crate::ln::channelmanager::ChannelManager::send_probe
 501                 payment_id: PaymentId,
 502                 /// The hash generated by [`ChannelManager::send_probe`].
 503                 ///
 504                 /// [`ChannelManager::send_probe`]: crate::ln::channelmanager::ChannelManager::send_probe
 505                 payment_hash: PaymentHash,
 506                 /// The payment path that was successful.
 507                 path: Vec<RouteHop>,
 508         },
 509         /// Indicates that a probe payment we sent failed at an intermediary node on the path.
 510         ProbeFailed {
 511                 /// The id returned by [`ChannelManager::send_probe`].
 512                 ///
 513                 /// [`ChannelManager::send_probe`]: crate::ln::channelmanager::ChannelManager::send_probe
 514                 payment_id: PaymentId,
 515                 /// The hash generated by [`ChannelManager::send_probe`].
 516                 ///
 517                 /// [`ChannelManager::send_probe`]: crate::ln::channelmanager::ChannelManager::send_probe
 518                 payment_hash: PaymentHash,
 519                 /// The payment path that failed.
 520                 path: Vec<RouteHop>,
 521                 /// The channel responsible for the failed probe.
 522                 ///
 523                 /// Note that for route hints or for the first hop in a path this may be an SCID alias and
 524                 /// may not refer to a channel in the public network graph. These aliases may also collide
 525                 /// with channels in the public network graph.
 526                 short_channel_id: Option<u64>,
 527         },
 528         /// Used to indicate that [`ChannelManager::process_pending_htlc_forwards`] should be called at
 529         /// a time in the future.
 530         ///
 531         /// [`ChannelManager::process_pending_htlc_forwards`]: crate::ln::channelmanager::ChannelManager::process_pending_htlc_forwards
 532         PendingHTLCsForwardable {
 533                 /// The minimum amount of time that should be waited prior to calling
 534                 /// process_pending_htlc_forwards. To increase the effort required to correlate payments,
 535                 /// you should wait a random amount of time in roughly the range (now + time_forwardable,
 536                 /// now + 5*time_forwardable).
 537                 time_forwardable: Duration,
 538         },
 539         /// Used to indicate that we've intercepted an HTLC forward. This event will only be generated if
 540         /// you've encoded an intercept scid in the receiver's invoice route hints using
 541         /// [`ChannelManager::get_intercept_scid`] and have set [`UserConfig::accept_intercept_htlcs`].
 542         ///
 543         /// [`ChannelManager::forward_intercepted_htlc`] or
 544         /// [`ChannelManager::fail_intercepted_htlc`] MUST be called in response to this event. See
 545         /// their docs for more information.
 546         ///
 547         /// [`ChannelManager::get_intercept_scid`]: crate::ln::channelmanager::ChannelManager::get_intercept_scid
 548         /// [`UserConfig::accept_intercept_htlcs`]: crate::util::config::UserConfig::accept_intercept_htlcs
 549         /// [`ChannelManager::forward_intercepted_htlc`]: crate::ln::channelmanager::ChannelManager::forward_intercepted_htlc
 550         /// [`ChannelManager::fail_intercepted_htlc`]: crate::ln::channelmanager::ChannelManager::fail_intercepted_htlc
 551         HTLCIntercepted {
 552                 /// An id to help LDK identify which HTLC is being forwarded or failed.
 553                 intercept_id: InterceptId,
 554                 /// The fake scid that was programmed as the next hop's scid, generated using
 555                 /// [`ChannelManager::get_intercept_scid`].
 556                 ///
 557                 /// [`ChannelManager::get_intercept_scid`]: crate::ln::channelmanager::ChannelManager::get_intercept_scid
 558                 requested_next_hop_scid: u64,
 559                 /// The payment hash used for this HTLC.
 560                 payment_hash: PaymentHash,
 561                 /// How many msats were received on the inbound edge of this HTLC.
 562                 inbound_amount_msat: u64,
 563                 /// How many msats the payer intended to route to the next node. Depending on the reason you are
 564                 /// intercepting this payment, you might take a fee by forwarding less than this amount.
 565                 ///
 566                 /// Note that LDK will NOT check that expected fees were factored into this value. You MUST
 567                 /// check that whatever fee you want has been included here or subtract it as required. Further,
 568                 /// LDK will not stop you from forwarding more than you received.
 569                 expected_outbound_amount_msat: u64,
 570         },
 571         /// Used to indicate that an output which you should know how to spend was confirmed on chain
 572         /// and is now spendable.
 573         /// Such an output will *not* ever be spent by rust-lightning, and are not at risk of your
 574         /// counterparty spending them due to some kind of timeout. Thus, you need to store them
 575         /// somewhere and spend them when you create on-chain transactions.
 576         SpendableOutputs {
 577                 /// The outputs which you should store as spendable by you.
 578                 outputs: Vec<SpendableOutputDescriptor>,
 579         },
 580         /// This event is generated when a payment has been successfully forwarded through us and a
 581         /// forwarding fee earned.
 582         PaymentForwarded {
 583                 /// The incoming channel between the previous node and us. This is only `None` for events
 584                 /// generated or serialized by versions prior to 0.0.107.
 585                 prev_channel_id: Option<[u8; 32]>,
 586                 /// The outgoing channel between the next node and us. This is only `None` for events
 587                 /// generated or serialized by versions prior to 0.0.107.
 588                 next_channel_id: Option<[u8; 32]>,
 589                 /// The fee, in milli-satoshis, which was earned as a result of the payment.
 590                 ///
 591                 /// Note that if we force-closed the channel over which we forwarded an HTLC while the HTLC
 592                 /// was pending, the amount the next hop claimed will have been rounded down to the nearest
 593                 /// whole satoshi. Thus, the fee calculated here may be higher than expected as we still
 594                 /// claimed the full value in millisatoshis from the source. In this case,
 595                 /// `claim_from_onchain_tx` will be set.
 596                 ///
 597                 /// If the channel which sent us the payment has been force-closed, we will claim the funds
 598                 /// via an on-chain transaction. In that case we do not yet know the on-chain transaction
 599                 /// fees which we will spend and will instead set this to `None`. It is possible duplicate
 600                 /// `PaymentForwarded` events are generated for the same payment iff `fee_earned_msat` is
 601                 /// `None`.
 602                 fee_earned_msat: Option<u64>,
 603                 /// If this is `true`, the forwarded HTLC was claimed by our counterparty via an on-chain
 604                 /// transaction.
 605                 claim_from_onchain_tx: bool,
 606                 /// The final amount forwarded, in milli-satoshis, after the fee is deducted.
 607                 ///
 608                 /// The caveat described above the `fee_earned_msat` field applies here as well.
 609                 outbound_amount_forwarded_msat: Option<u64>,
 610         },
 611         /// Used to indicate that a channel with the given `channel_id` is ready to
 612         /// be used. This event is emitted either when the funding transaction has been confirmed
 613         /// on-chain, or, in case of a 0conf channel, when both parties have confirmed the channel
 614         /// establishment.
 615         ChannelReady {
 616                 /// The channel_id of the channel that is ready.
 617                 channel_id: [u8; 32],
 618                 /// The `user_channel_id` value passed in to [`ChannelManager::create_channel`] for outbound
 619                 /// channels, or to [`ChannelManager::accept_inbound_channel`] for inbound channels if
 620                 /// [`UserConfig::manually_accept_inbound_channels`] config flag is set to true. Otherwise
 621                 /// `user_channel_id` will be randomized for an inbound channel.
 622                 ///
 623                 /// [`ChannelManager::create_channel`]: crate::ln::channelmanager::ChannelManager::create_channel
 624                 /// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
 625                 /// [`UserConfig::manually_accept_inbound_channels`]: crate::util::config::UserConfig::manually_accept_inbound_channels
 626                 user_channel_id: u128,
 627                 /// The node_id of the channel counterparty.
 628                 counterparty_node_id: PublicKey,
 629                 /// The features that this channel will operate with.
 630                 channel_type: ChannelTypeFeatures,
 631         },
 632         /// Used to indicate that a previously opened channel with the given `channel_id` is in the
 633         /// process of closure.
 634         ChannelClosed  {
 635                 /// The channel_id of the channel which has been closed. Note that on-chain transactions
 636                 /// resolving the channel are likely still awaiting confirmation.
 637                 channel_id: [u8; 32],
 638                 /// The `user_channel_id` value passed in to [`ChannelManager::create_channel`] for outbound
 639                 /// channels, or to [`ChannelManager::accept_inbound_channel`] for inbound channels if
 640                 /// [`UserConfig::manually_accept_inbound_channels`] config flag is set to true. Otherwise
 641                 /// `user_channel_id` will be randomized for inbound channels.
 642                 /// This may be zero for inbound channels serialized prior to 0.0.113 and will always be
 643                 /// zero for objects serialized with LDK versions prior to 0.0.102.
 644                 ///
 645                 /// [`ChannelManager::create_channel`]: crate::ln::channelmanager::ChannelManager::create_channel
 646                 /// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
 647                 /// [`UserConfig::manually_accept_inbound_channels`]: crate::util::config::UserConfig::manually_accept_inbound_channels
 648                 user_channel_id: u128,
 649                 /// The reason the channel was closed.
 650                 reason: ClosureReason
 651         },
 652         /// Used to indicate to the user that they can abandon the funding transaction and recycle the
 653         /// inputs for another purpose.
 654         DiscardFunding {
 655                 /// The channel_id of the channel which has been closed.
 656                 channel_id: [u8; 32],
 657                 /// The full transaction received from the user
 658                 transaction: Transaction
 659         },
 660         /// Indicates a request to open a new channel by a peer.
 661         ///
 662         /// To accept the request, call [`ChannelManager::accept_inbound_channel`]. To reject the
 663         /// request, call [`ChannelManager::force_close_without_broadcasting_txn`].
 664         ///
 665         /// The event is only triggered when a new open channel request is received and the
 666         /// [`UserConfig::manually_accept_inbound_channels`] config flag is set to true.
 667         ///
 668         /// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
 669         /// [`ChannelManager::force_close_without_broadcasting_txn`]: crate::ln::channelmanager::ChannelManager::force_close_without_broadcasting_txn
 670         /// [`UserConfig::manually_accept_inbound_channels`]: crate::util::config::UserConfig::manually_accept_inbound_channels
 671         OpenChannelRequest {
 672                 /// The temporary channel ID of the channel requested to be opened.
 673                 ///
 674                 /// When responding to the request, the `temporary_channel_id` should be passed
 675                 /// back to the ChannelManager through [`ChannelManager::accept_inbound_channel`] to accept,
 676                 /// or through [`ChannelManager::force_close_without_broadcasting_txn`] to reject.
 677                 ///
 678                 /// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
 679                 /// [`ChannelManager::force_close_without_broadcasting_txn`]: crate::ln::channelmanager::ChannelManager::force_close_without_broadcasting_txn
 680                 temporary_channel_id: [u8; 32],
 681                 /// The node_id of the counterparty requesting to open the channel.
 682                 ///
 683                 /// When responding to the request, the `counterparty_node_id` should be passed
 684                 /// back to the `ChannelManager` through [`ChannelManager::accept_inbound_channel`] to
 685                 /// accept the request, or through [`ChannelManager::force_close_without_broadcasting_txn`] to reject the
 686                 /// request.
 687                 ///
 688                 /// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
 689                 /// [`ChannelManager::force_close_without_broadcasting_txn`]: crate::ln::channelmanager::ChannelManager::force_close_without_broadcasting_txn
 690                 counterparty_node_id: PublicKey,
 691                 /// The channel value of the requested channel.
 692                 funding_satoshis: u64,
 693                 /// Our starting balance in the channel if the request is accepted, in milli-satoshi.
 694                 push_msat: u64,
 695                 /// The features that this channel will operate with. If you reject the channel, a
 696                 /// well-behaved counterparty may automatically re-attempt the channel with a new set of
 697                 /// feature flags.
 698                 ///
 699                 /// Note that if [`ChannelTypeFeatures::supports_scid_privacy`] returns true on this type,
 700                 /// the resulting [`ChannelManager`] will not be readable by versions of LDK prior to
 701                 /// 0.0.106.
 702                 ///
 703                 /// Furthermore, note that if [`ChannelTypeFeatures::supports_zero_conf`] returns true on this type,
 704                 /// the resulting [`ChannelManager`] will not be readable by versions of LDK prior to
 705                 /// 0.0.107. Channels setting this type also need to get manually accepted via
 706                 /// [`crate::ln::channelmanager::ChannelManager::accept_inbound_channel_from_trusted_peer_0conf`],
 707                 /// or will be rejected otherwise.
 708                 ///
 709                 /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
 710                 channel_type: ChannelTypeFeatures,
 711         },
 712         /// Indicates that the HTLC was accepted, but could not be processed when or after attempting to
 713         /// forward it.
 714         ///
 715         /// Some scenarios where this event may be sent include:
 716         /// * Insufficient capacity in the outbound channel
 717         /// * While waiting to forward the HTLC, the channel it is meant to be forwarded through closes
 718         /// * When an unknown SCID is requested for forwarding a payment.
 719         /// * Expected MPP amount has already been reached
 720         /// * The HTLC has timed out
 721         ///
 722         /// This event, however, does not get generated if an HTLC fails to meet the forwarding
 723         /// requirements (i.e. insufficient fees paid, or a CLTV that is too soon).
 724         HTLCHandlingFailed {
 725                 /// The channel over which the HTLC was received.
 726                 prev_channel_id: [u8; 32],
 727                 /// Destination of the HTLC that failed to be processed.
 728                 failed_next_destination: HTLCDestination,
 729         },
 730         #[cfg(anchors)]
 731         /// Indicates that a transaction originating from LDK needs to have its fee bumped. This event
 732         /// requires confirmed external funds to be readily available to spend.
 733         ///
 734         /// LDK does not currently generate this event. It is limited to the scope of channels with
 735         /// anchor outputs, which will be introduced in a future release.
 736         BumpTransaction(BumpTransactionEvent),
 737 }
 738
 739 impl Writeable for Event {
 740         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 741                 match self {
 742                         &Event::FundingGenerationReady { .. } => {
 743                                 0u8.write(writer)?;
 744                                 // We never write out FundingGenerationReady events as, upon disconnection, peers
 745                                 // drop any channels which have not yet exchanged funding_signed.
 746                         },
 747                         &Event::PaymentClaimable { ref payment_hash, ref amount_msat, ref purpose, ref receiver_node_id, ref via_channel_id, ref via_user_channel_id } => {
 748                                 1u8.write(writer)?;
 749                                 let mut payment_secret = None;
 750                                 let payment_preimage;
 751                                 match &purpose {
 752                                         PaymentPurpose::InvoicePayment { payment_preimage: preimage, payment_secret: secret } => {
 753                                                 payment_secret = Some(secret);
 754                                                 payment_preimage = *preimage;
 755                                         },
 756                                         PaymentPurpose::SpontaneousPayment(preimage) => {
 757                                                 payment_preimage = Some(*preimage);
 758                                         }
 759                                 }
 760                                 write_tlv_fields!(writer, {
 761                                         (0, payment_hash, required),
 762                                         (1, receiver_node_id, option),
 763                                         (2, payment_secret, option),
 764                                         (3, via_channel_id, option),
 765                                         (4, amount_msat, required),
 766                                         (5, via_user_channel_id, option),
 767                                         (6, 0u64, required), // user_payment_id required for compatibility with 0.0.103 and earlier
 768                                         (8, payment_preimage, option),
 769                                 });
 770                         },
 771                         &Event::PaymentSent { ref payment_id, ref payment_preimage, ref payment_hash, ref fee_paid_msat } => {
 772                                 2u8.write(writer)?;
 773                                 write_tlv_fields!(writer, {
 774                                         (0, payment_preimage, required),
 775                                         (1, payment_hash, required),
 776                                         (3, payment_id, option),
 777                                         (5, fee_paid_msat, option),
 778                                 });
 779                         },
 780                         &Event::PaymentPathFailed {
 781                                 ref payment_id, ref payment_hash, ref payment_failed_permanently, ref failure,
 782                                 ref path, ref short_channel_id,
 783                                 #[cfg(test)]
 784                                 ref error_code,
 785                                 #[cfg(test)]
 786                                 ref error_data,
 787                         } => {
 788                                 3u8.write(writer)?;
 789                                 #[cfg(test)]
 790                                 error_code.write(writer)?;
 791                                 #[cfg(test)]
 792                                 error_data.write(writer)?;
 793                                 write_tlv_fields!(writer, {
 794                                         (0, payment_hash, required),
 795                                         (1, None::<NetworkUpdate>, option), // network_update in LDK versions prior to 0.0.114
 796                                         (2, payment_failed_permanently, required),
 797                                         (3, false, required), // all_paths_failed in LDK versions prior to 0.0.114
 798                                         (5, *path, vec_type),
 799                                         (7, short_channel_id, option),
 800                                         (9, None::<RouteParameters>, option), // retry in LDK versions prior to 0.0.115
 801                                         (11, payment_id, option),
 802                                         (13, failure, required),
 803                                 });
 804                         },
 805                         &Event::PendingHTLCsForwardable { time_forwardable: _ } => {
 806                                 4u8.write(writer)?;
 807                                 // Note that we now ignore these on the read end as we'll re-generate them in
 808                                 // ChannelManager, we write them here only for backwards compatibility.
 809                         },
 810                         &Event::SpendableOutputs { ref outputs } => {
 811                                 5u8.write(writer)?;
 812                                 write_tlv_fields!(writer, {
 813                                         (0, WithoutLength(outputs), required),
 814                                 });
 815                         },
 816                         &Event::HTLCIntercepted { requested_next_hop_scid, payment_hash, inbound_amount_msat, expected_outbound_amount_msat, intercept_id } => {
 817                                 6u8.write(writer)?;
 818                                 let intercept_scid = InterceptNextHop::FakeScid { requested_next_hop_scid };
 819                                 write_tlv_fields!(writer, {
 820                                         (0, intercept_id, required),
 821                                         (2, intercept_scid, required),
 822                                         (4, payment_hash, required),
 823                                         (6, inbound_amount_msat, required),
 824                                         (8, expected_outbound_amount_msat, required),
 825                                 });
 826                         }
 827                         &Event::PaymentForwarded {
 828                                 fee_earned_msat, prev_channel_id, claim_from_onchain_tx,
 829                                 next_channel_id, outbound_amount_forwarded_msat
 830                         } => {
 831                                 7u8.write(writer)?;
 832                                 write_tlv_fields!(writer, {
 833                                         (0, fee_earned_msat, option),
 834                                         (1, prev_channel_id, option),
 835                                         (2, claim_from_onchain_tx, required),
 836                                         (3, next_channel_id, option),
 837                                         (5, outbound_amount_forwarded_msat, option),
 838                                 });
 839                         },
 840                         &Event::ChannelClosed { ref channel_id, ref user_channel_id, ref reason } => {
 841                                 9u8.write(writer)?;
 842                                 // `user_channel_id` used to be a single u64 value. In order to remain backwards
 843                                 // compatible with versions prior to 0.0.113, the u128 is serialized as two
 844                                 // separate u64 values.
 845                                 let user_channel_id_low = *user_channel_id as u64;
 846                                 let user_channel_id_high = (*user_channel_id >> 64) as u64;
 847                                 write_tlv_fields!(writer, {
 848                                         (0, channel_id, required),
 849                                         (1, user_channel_id_low, required),
 850                                         (2, reason, required),
 851                                         (3, user_channel_id_high, required),
 852                                 });
 853                         },
 854                         &Event::DiscardFunding { ref channel_id, ref transaction } => {
 855                                 11u8.write(writer)?;
 856                                 write_tlv_fields!(writer, {
 857                                         (0, channel_id, required),
 858                                         (2, transaction, required)
 859                                 })
 860                         },
 861                         &Event::PaymentPathSuccessful { ref payment_id, ref payment_hash, ref path } => {
 862                                 13u8.write(writer)?;
 863                                 write_tlv_fields!(writer, {
 864                                         (0, payment_id, required),
 865                                         (2, payment_hash, option),
 866                                         (4, *path, vec_type)
 867                                 })
 868                         },
 869                         &Event::PaymentFailed { ref payment_id, ref payment_hash } => {
 870                                 15u8.write(writer)?;
 871                                 write_tlv_fields!(writer, {
 872                                         (0, payment_id, required),
 873                                         (2, payment_hash, required),
 874                                 })
 875                         },
 876                         &Event::OpenChannelRequest { .. } => {
 877                                 17u8.write(writer)?;
 878                                 // We never write the OpenChannelRequest events as, upon disconnection, peers
 879                                 // drop any channels which have not yet exchanged funding_signed.
 880                         },
 881                         &Event::PaymentClaimed { ref payment_hash, ref amount_msat, ref purpose, ref receiver_node_id } => {
 882                                 19u8.write(writer)?;
 883                                 write_tlv_fields!(writer, {
 884                                         (0, payment_hash, required),
 885                                         (1, receiver_node_id, option),
 886                                         (2, purpose, required),
 887                                         (4, amount_msat, required),
 888                                 });
 889                         },
 890                         &Event::ProbeSuccessful { ref payment_id, ref payment_hash, ref path } => {
 891                                 21u8.write(writer)?;
 892                                 write_tlv_fields!(writer, {
 893                                         (0, payment_id, required),
 894                                         (2, payment_hash, required),
 895                                         (4, *path, vec_type)
 896                                 })
 897                         },
 898                         &Event::ProbeFailed { ref payment_id, ref payment_hash, ref path, ref short_channel_id } => {
 899                                 23u8.write(writer)?;
 900                                 write_tlv_fields!(writer, {
 901                                         (0, payment_id, required),
 902                                         (2, payment_hash, required),
 903                                         (4, *path, vec_type),
 904                                         (6, short_channel_id, option),
 905                                 })
 906                         },
 907                         &Event::HTLCHandlingFailed { ref prev_channel_id, ref failed_next_destination } => {
 908                                 25u8.write(writer)?;
 909                                 write_tlv_fields!(writer, {
 910                                         (0, prev_channel_id, required),
 911                                         (2, failed_next_destination, required),
 912                                 })
 913                         },
 914                         #[cfg(anchors)]
 915                         &Event::BumpTransaction(ref event)=> {
 916                                 27u8.write(writer)?;
 917                                 match event {
 918                                         // We never write the ChannelClose|HTLCResolution events as they'll be replayed
 919                                         // upon restarting anyway if they remain unresolved.
 920                                         BumpTransactionEvent::ChannelClose { .. } => {}
 921                                         BumpTransactionEvent::HTLCResolution { .. } => {}
 922                                 }
 923                                 write_tlv_fields!(writer, {}); // Write a length field for forwards compat
 924                         }
 925                         &Event::ChannelReady { ref channel_id, ref user_channel_id, ref counterparty_node_id, ref channel_type } => {
 926                                 29u8.write(writer)?;
 927                                 write_tlv_fields!(writer, {
 928                                         (0, channel_id, required),
 929                                         (2, user_channel_id, required),
 930                                         (4, counterparty_node_id, required),
 931                                         (6, channel_type, required),
 932                                 });
 933                         },
 934                         // Note that, going forward, all new events must only write data inside of
 935                         // `write_tlv_fields`. Versions 0.0.101+ will ignore odd-numbered events that write
 936                         // data via `write_tlv_fields`.
 937                 }
 938                 Ok(())
 939         }
 940 }
 941 impl MaybeReadable for Event {
 942         fn read<R: io::Read>(reader: &mut R) -> Result<Option<Self>, msgs::DecodeError> {
 943                 match Readable::read(reader)? {
 944                         // Note that we do not write a length-prefixed TLV for FundingGenerationReady events,
 945                         // unlike all other events, thus we return immediately here.
 946                         0u8 => Ok(None),
 947                         1u8 => {
 948                                 let f = || {
 949                                         let mut payment_hash = PaymentHash([0; 32]);
 950                                         let mut payment_preimage = None;
 951                                         let mut payment_secret = None;
 952                                         let mut amount_msat = 0;
 953                                         let mut receiver_node_id = None;
 954                                         let mut _user_payment_id = None::<u64>; // For compatibility with 0.0.103 and earlier
 955                                         let mut via_channel_id = None;
 956                                         let mut via_user_channel_id = None;
 957                                         read_tlv_fields!(reader, {
 958                                                 (0, payment_hash, required),
 959                                                 (1, receiver_node_id, option),
 960                                                 (2, payment_secret, option),
 961                                                 (3, via_channel_id, option),
 962                                                 (4, amount_msat, required),
 963                                                 (5, via_user_channel_id, option),
 964                                                 (6, _user_payment_id, option),
 965                                                 (8, payment_preimage, option),
 966                                         });
 967                                         let purpose = match payment_secret {
 968                                                 Some(secret) => PaymentPurpose::InvoicePayment {
 969                                                         payment_preimage,
 970                                                         payment_secret: secret
 971                                                 },
 972                                                 None if payment_preimage.is_some() => PaymentPurpose::SpontaneousPayment(payment_preimage.unwrap()),
 973                                                 None => return Err(msgs::DecodeError::InvalidValue),
 974                                         };
 975                                         Ok(Some(Event::PaymentClaimable {
 976                                                 receiver_node_id,
 977                                                 payment_hash,
 978                                                 amount_msat,
 979                                                 purpose,
 980                                                 via_channel_id,
 981                                                 via_user_channel_id,
 982                                         }))
 983                                 };
 984                                 f()
 985                         },
 986                         2u8 => {
 987                                 let f = || {
 988                                         let mut payment_preimage = PaymentPreimage([0; 32]);
 989                                         let mut payment_hash = None;
 990                                         let mut payment_id = None;
 991                                         let mut fee_paid_msat = None;
 992                                         read_tlv_fields!(reader, {
 993                                                 (0, payment_preimage, required),
 994                                                 (1, payment_hash, option),
 995                                                 (3, payment_id, option),
 996                                                 (5, fee_paid_msat, option),
 997                                         });
 998                                         if payment_hash.is_none() {
 999                                                 payment_hash = Some(PaymentHash(Sha256::hash(&payment_preimage.0[..]).into_inner()));
1000                                         }
1001                                         Ok(Some(Event::PaymentSent {
1002                                                 payment_id,
1003                                                 payment_preimage,
1004                                                 payment_hash: payment_hash.unwrap(),
1005                                                 fee_paid_msat,
1006                                         }))
1007                                 };
1008                                 f()
1009                         },
1010                         3u8 => {
1011                                 let f = || {
1012                                         #[cfg(test)]
1013                                         let error_code = Readable::read(reader)?;
1014                                         #[cfg(test)]
1015                                         let error_data = Readable::read(reader)?;
1016                                         let mut payment_hash = PaymentHash([0; 32]);
1017                                         let mut payment_failed_permanently = false;
1018                                         let mut network_update = None;
1019                                         let mut path: Option<Vec<RouteHop>> = Some(vec![]);
1020                                         let mut short_channel_id = None;
1021                                         let mut payment_id = None;
1022                                         let mut failure_opt = None;
1023                                         read_tlv_fields!(reader, {
1024                                                 (0, payment_hash, required),
1025                                                 (1, network_update, upgradable_option),
1026                                                 (2, payment_failed_permanently, required),
1027                                                 (5, path, vec_type),
1028                                                 (7, short_channel_id, option),
1029                                                 (11, payment_id, option),
1030                                                 (13, failure_opt, upgradable_option),
1031                                         });
1032                                         let failure = failure_opt.unwrap_or_else(|| PathFailure::OnPath { network_update });
1033                                         Ok(Some(Event::PaymentPathFailed {
1034                                                 payment_id,
1035                                                 payment_hash,
1036                                                 payment_failed_permanently,
1037                                                 failure,
1038                                                 path: path.unwrap(),
1039                                                 short_channel_id,
1040                                                 #[cfg(test)]
1041                                                 error_code,
1042                                                 #[cfg(test)]
1043                                                 error_data,
1044                                         }))
1045                                 };
1046                                 f()
1047                         },
1048                         4u8 => Ok(None),
1049                         5u8 => {
1050                                 let f = || {
1051                                         let mut outputs = WithoutLength(Vec::new());
1052                                         read_tlv_fields!(reader, {
1053                                                 (0, outputs, required),
1054                                         });
1055                                         Ok(Some(Event::SpendableOutputs { outputs: outputs.0 }))
1056                                 };
1057                                 f()
1058                         },
1059                         6u8 => {
1060                                 let mut payment_hash = PaymentHash([0; 32]);
1061                                 let mut intercept_id = InterceptId([0; 32]);
1062                                 let mut requested_next_hop_scid = InterceptNextHop::FakeScid { requested_next_hop_scid: 0 };
1063                                 let mut inbound_amount_msat = 0;
1064                                 let mut expected_outbound_amount_msat = 0;
1065                                 read_tlv_fields!(reader, {
1066                                         (0, intercept_id, required),
1067                                         (2, requested_next_hop_scid, required),
1068                                         (4, payment_hash, required),
1069                                         (6, inbound_amount_msat, required),
1070                                         (8, expected_outbound_amount_msat, required),
1071                                 });
1072                                 let next_scid = match requested_next_hop_scid {
1073                                         InterceptNextHop::FakeScid { requested_next_hop_scid: scid } => scid
1074                                 };
1075                                 Ok(Some(Event::HTLCIntercepted {
1076                                         payment_hash,
1077                                         requested_next_hop_scid: next_scid,
1078                                         inbound_amount_msat,
1079                                         expected_outbound_amount_msat,
1080                                         intercept_id,
1081                                 }))
1082                         },
1083                         7u8 => {
1084                                 let f = || {
1085                                         let mut fee_earned_msat = None;
1086                                         let mut prev_channel_id = None;
1087                                         let mut claim_from_onchain_tx = false;
1088                                         let mut next_channel_id = None;
1089                                         let mut outbound_amount_forwarded_msat = None;
1090                                         read_tlv_fields!(reader, {
1091                                                 (0, fee_earned_msat, option),
1092                                                 (1, prev_channel_id, option),
1093                                                 (2, claim_from_onchain_tx, required),
1094                                                 (3, next_channel_id, option),
1095                                                 (5, outbound_amount_forwarded_msat, option),
1096                                         });
1097                                         Ok(Some(Event::PaymentForwarded {
1098                                                 fee_earned_msat, prev_channel_id, claim_from_onchain_tx, next_channel_id,
1099                                                 outbound_amount_forwarded_msat
1100                                         }))
1101                                 };
1102                                 f()
1103                         },
1104                         9u8 => {
1105                                 let f = || {
1106                                         let mut channel_id = [0; 32];
1107                                         let mut reason = UpgradableRequired(None);
1108                                         let mut user_channel_id_low_opt: Option<u64> = None;
1109                                         let mut user_channel_id_high_opt: Option<u64> = None;
1110                                         read_tlv_fields!(reader, {
1111                                                 (0, channel_id, required),
1112                                                 (1, user_channel_id_low_opt, option),
1113                                                 (2, reason, upgradable_required),
1114                                                 (3, user_channel_id_high_opt, option),
1115                                         });
1116
1117                                         // `user_channel_id` used to be a single u64 value. In order to remain
1118                                         // backwards compatible with versions prior to 0.0.113, the u128 is serialized
1119                                         // as two separate u64 values.
1120                                         let user_channel_id = (user_channel_id_low_opt.unwrap_or(0) as u128) +
1121                                                 ((user_channel_id_high_opt.unwrap_or(0) as u128) << 64);
1122
1123                                         Ok(Some(Event::ChannelClosed { channel_id, user_channel_id, reason: _init_tlv_based_struct_field!(reason, upgradable_required) }))
1124                                 };
1125                                 f()
1126                         },
1127                         11u8 => {
1128                                 let f = || {
1129                                         let mut channel_id = [0; 32];
1130                                         let mut transaction = Transaction{ version: 2, lock_time: PackedLockTime::ZERO, input: Vec::new(), output: Vec::new() };
1131                                         read_tlv_fields!(reader, {
1132                                                 (0, channel_id, required),
1133                                                 (2, transaction, required),
1134                                         });
1135                                         Ok(Some(Event::DiscardFunding { channel_id, transaction } ))
1136                                 };
1137                                 f()
1138                         },
1139                         13u8 => {
1140                                 let f = || {
1141                                         let mut payment_id = PaymentId([0; 32]);
1142                                         let mut payment_hash = None;
1143                                         let mut path: Option<Vec<RouteHop>> = Some(vec![]);
1144                                         read_tlv_fields!(reader, {
1145                                                 (0, payment_id, required),
1146                                                 (2, payment_hash, option),
1147                                                 (4, path, vec_type),
1148                                         });
1149                                         Ok(Some(Event::PaymentPathSuccessful {
1150                                                 payment_id,
1151                                                 payment_hash,
1152                                                 path: path.unwrap(),
1153                                         }))
1154                                 };
1155                                 f()
1156                         },
1157                         15u8 => {
1158                                 let f = || {
1159                                         let mut payment_hash = PaymentHash([0; 32]);
1160                                         let mut payment_id = PaymentId([0; 32]);
1161                                         read_tlv_fields!(reader, {
1162                                                 (0, payment_id, required),
1163                                                 (2, payment_hash, required),
1164                                         });
1165                                         Ok(Some(Event::PaymentFailed {
1166                                                 payment_id,
1167                                                 payment_hash,
1168                                         }))
1169                                 };
1170                                 f()
1171                         },
1172                         17u8 => {
1173                                 // Value 17 is used for `Event::OpenChannelRequest`.
1174                                 Ok(None)
1175                         },
1176                         19u8 => {
1177                                 let f = || {
1178                                         let mut payment_hash = PaymentHash([0; 32]);
1179                                         let mut purpose = UpgradableRequired(None);
1180                                         let mut amount_msat = 0;
1181                                         let mut receiver_node_id = None;
1182                                         read_tlv_fields!(reader, {
1183                                                 (0, payment_hash, required),
1184                                                 (1, receiver_node_id, option),
1185                                                 (2, purpose, upgradable_required),
1186                                                 (4, amount_msat, required),
1187                                         });
1188                                         Ok(Some(Event::PaymentClaimed {
1189                                                 receiver_node_id,
1190                                                 payment_hash,
1191                                                 purpose: _init_tlv_based_struct_field!(purpose, upgradable_required),
1192                                                 amount_msat,
1193                                         }))
1194                                 };
1195                                 f()
1196                         },
1197                         21u8 => {
1198                                 let f = || {
1199                                         let mut payment_id = PaymentId([0; 32]);
1200                                         let mut payment_hash = PaymentHash([0; 32]);
1201                                         let mut path: Option<Vec<RouteHop>> = Some(vec![]);
1202                                         read_tlv_fields!(reader, {
1203                                                 (0, payment_id, required),
1204                                                 (2, payment_hash, required),
1205                                                 (4, path, vec_type),
1206                                         });
1207                                         Ok(Some(Event::ProbeSuccessful {
1208                                                 payment_id,
1209                                                 payment_hash,
1210                                                 path: path.unwrap(),
1211                                         }))
1212                                 };
1213                                 f()
1214                         },
1215                         23u8 => {
1216                                 let f = || {
1217                                         let mut payment_id = PaymentId([0; 32]);
1218                                         let mut payment_hash = PaymentHash([0; 32]);
1219                                         let mut path: Option<Vec<RouteHop>> = Some(vec![]);
1220                                         let mut short_channel_id = None;
1221                                         read_tlv_fields!(reader, {
1222                                                 (0, payment_id, required),
1223                                                 (2, payment_hash, required),
1224                                                 (4, path, vec_type),
1225                                                 (6, short_channel_id, option),
1226                                         });
1227                                         Ok(Some(Event::ProbeFailed {
1228                                                 payment_id,
1229                                                 payment_hash,
1230                                                 path: path.unwrap(),
1231                                                 short_channel_id,
1232                                         }))
1233                                 };
1234                                 f()
1235                         },
1236                         25u8 => {
1237                                 let f = || {
1238                                         let mut prev_channel_id = [0; 32];
1239                                         let mut failed_next_destination_opt = UpgradableRequired(None);
1240                                         read_tlv_fields!(reader, {
1241                                                 (0, prev_channel_id, required),
1242                                                 (2, failed_next_destination_opt, upgradable_required),
1243                                         });
1244                                         Ok(Some(Event::HTLCHandlingFailed {
1245                                                 prev_channel_id,
1246                                                 failed_next_destination: _init_tlv_based_struct_field!(failed_next_destination_opt, upgradable_required),
1247                                         }))
1248                                 };
1249                                 f()
1250                         },
1251                         27u8 => Ok(None),
1252                         29u8 => {
1253                                 let f = || {
1254                                         let mut channel_id = [0; 32];
1255                                         let mut user_channel_id: u128 = 0;
1256                                         let mut counterparty_node_id = RequiredWrapper(None);
1257                                         let mut channel_type = RequiredWrapper(None);
1258                                         read_tlv_fields!(reader, {
1259                                                 (0, channel_id, required),
1260                                                 (2, user_channel_id, required),
1261                                                 (4, counterparty_node_id, required),
1262                                                 (6, channel_type, required),
1263                                         });
1264
1265                                         Ok(Some(Event::ChannelReady {
1266                                                 channel_id,
1267                                                 user_channel_id,
1268                                                 counterparty_node_id: counterparty_node_id.0.unwrap(),
1269                                                 channel_type: channel_type.0.unwrap()
1270                                         }))
1271                                 };
1272                                 f()
1273                         },
1274                         // Versions prior to 0.0.100 did not ignore odd types, instead returning InvalidValue.
1275                         // Version 0.0.100 failed to properly ignore odd types, possibly resulting in corrupt
1276                         // reads.
1277                         x if x % 2 == 1 => {
1278                                 // If the event is of unknown type, assume it was written with `write_tlv_fields`,
1279                                 // which prefixes the whole thing with a length BigSize. Because the event is
1280                                 // odd-type unknown, we should treat it as `Ok(None)` even if it has some TLV
1281                                 // fields that are even. Thus, we avoid using `read_tlv_fields` and simply read
1282                                 // exactly the number of bytes specified, ignoring them entirely.
1283                                 let tlv_len: BigSize = Readable::read(reader)?;
1284                                 FixedLengthReader::new(reader, tlv_len.0)
1285                                         .eat_remaining().map_err(|_| msgs::DecodeError::ShortRead)?;
1286                                 Ok(None)
1287                         },
1288                         _ => Err(msgs::DecodeError::InvalidValue)
1289                 }
1290         }
1291 }
1292
1293 /// An event generated by ChannelManager which indicates a message should be sent to a peer (or
1294 /// broadcast to most peers).
1295 /// These events are handled by PeerManager::process_events if you are using a PeerManager.
1296 #[derive(Clone, Debug)]
1297 pub enum MessageSendEvent {
1298         /// Used to indicate that we've accepted a channel open and should send the accept_channel
1299         /// message provided to the given peer.
1300         SendAcceptChannel {
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::AcceptChannel,
1305         },
1306         /// Used to indicate that we've initiated a channel open and should send the open_channel
1307         /// message provided to the given peer.
1308         SendOpenChannel {
1309                 /// The node_id of the node which should receive this message
1310                 node_id: PublicKey,
1311                 /// The message which should be sent.
1312                 msg: msgs::OpenChannel,
1313         },
1314         /// Used to indicate that a funding_created message should be sent to the peer with the given node_id.
1315         SendFundingCreated {
1316                 /// The node_id of the node which should receive this message
1317                 node_id: PublicKey,
1318                 /// The message which should be sent.
1319                 msg: msgs::FundingCreated,
1320         },
1321         /// Used to indicate that a funding_signed message should be sent to the peer with the given node_id.
1322         SendFundingSigned {
1323                 /// The node_id of the node which should receive this message
1324                 node_id: PublicKey,
1325                 /// The message which should be sent.
1326                 msg: msgs::FundingSigned,
1327         },
1328         /// Used to indicate that a channel_ready message should be sent to the peer with the given node_id.
1329         SendChannelReady {
1330                 /// The node_id of the node which should receive these message(s)
1331                 node_id: PublicKey,
1332                 /// The channel_ready message which should be sent.
1333                 msg: msgs::ChannelReady,
1334         },
1335         /// Used to indicate that an announcement_signatures message should be sent to the peer with the given node_id.
1336         SendAnnouncementSignatures {
1337                 /// The node_id of the node which should receive these message(s)
1338                 node_id: PublicKey,
1339                 /// The announcement_signatures message which should be sent.
1340                 msg: msgs::AnnouncementSignatures,
1341         },
1342         /// Used to indicate that a series of HTLC update messages, as well as a commitment_signed
1343         /// message should be sent to the peer with the given node_id.
1344         UpdateHTLCs {
1345                 /// The node_id of the node which should receive these message(s)
1346                 node_id: PublicKey,
1347                 /// The update messages which should be sent. ALL messages in the struct should be sent!
1348                 updates: msgs::CommitmentUpdate,
1349         },
1350         /// Used to indicate that a revoke_and_ack message should be sent to the peer with the given node_id.
1351         SendRevokeAndACK {
1352                 /// The node_id of the node which should receive this message
1353                 node_id: PublicKey,
1354                 /// The message which should be sent.
1355                 msg: msgs::RevokeAndACK,
1356         },
1357         /// Used to indicate that a closing_signed message should be sent to the peer with the given node_id.
1358         SendClosingSigned {
1359                 /// The node_id of the node which should receive this message
1360                 node_id: PublicKey,
1361                 /// The message which should be sent.
1362                 msg: msgs::ClosingSigned,
1363         },
1364         /// Used to indicate that a shutdown message should be sent to the peer with the given node_id.
1365         SendShutdown {
1366                 /// The node_id of the node which should receive this message
1367                 node_id: PublicKey,
1368                 /// The message which should be sent.
1369                 msg: msgs::Shutdown,
1370         },
1371         /// Used to indicate that a channel_reestablish message should be sent to the peer with the given node_id.
1372         SendChannelReestablish {
1373                 /// The node_id of the node which should receive this message
1374                 node_id: PublicKey,
1375                 /// The message which should be sent.
1376                 msg: msgs::ChannelReestablish,
1377         },
1378         /// Used to send a channel_announcement and channel_update to a specific peer, likely on
1379         /// initial connection to ensure our peers know about our channels.
1380         SendChannelAnnouncement {
1381                 /// The node_id of the node which should receive this message
1382                 node_id: PublicKey,
1383                 /// The channel_announcement which should be sent.
1384                 msg: msgs::ChannelAnnouncement,
1385                 /// The followup channel_update which should be sent.
1386                 update_msg: msgs::ChannelUpdate,
1387         },
1388         /// Used to indicate that a channel_announcement and channel_update should be broadcast to all
1389         /// peers (except the peer with node_id either msg.contents.node_id_1 or msg.contents.node_id_2).
1390         ///
1391         /// Note that after doing so, you very likely (unless you did so very recently) want to
1392         /// broadcast a node_announcement (e.g. via [`PeerManager::broadcast_node_announcement`]). This
1393         /// ensures that any nodes which see our channel_announcement also have a relevant
1394         /// node_announcement, including relevant feature flags which may be important for routing
1395         /// through or to us.
1396         ///
1397         /// [`PeerManager::broadcast_node_announcement`]: crate::ln::peer_handler::PeerManager::broadcast_node_announcement
1398         BroadcastChannelAnnouncement {
1399                 /// The channel_announcement which should be sent.
1400                 msg: msgs::ChannelAnnouncement,
1401                 /// The followup channel_update which should be sent.
1402                 update_msg: Option<msgs::ChannelUpdate>,
1403         },
1404         /// Used to indicate that a channel_update should be broadcast to all peers.
1405         BroadcastChannelUpdate {
1406                 /// The channel_update which should be sent.
1407                 msg: msgs::ChannelUpdate,
1408         },
1409         /// Used to indicate that a node_announcement should be broadcast to all peers.
1410         BroadcastNodeAnnouncement {
1411                 /// The node_announcement which should be sent.
1412                 msg: msgs::NodeAnnouncement,
1413         },
1414         /// Used to indicate that a channel_update should be sent to a single peer.
1415         /// In contrast to [`Self::BroadcastChannelUpdate`], this is used when the channel is a
1416         /// private channel and we shouldn't be informing all of our peers of channel parameters.
1417         SendChannelUpdate {
1418                 /// The node_id of the node which should receive this message
1419                 node_id: PublicKey,
1420                 /// The channel_update which should be sent.
1421                 msg: msgs::ChannelUpdate,
1422         },
1423         /// Broadcast an error downstream to be handled
1424         HandleError {
1425                 /// The node_id of the node which should receive this message
1426                 node_id: PublicKey,
1427                 /// The action which should be taken.
1428                 action: msgs::ErrorAction
1429         },
1430         /// Query a peer for channels with funding transaction UTXOs in a block range.
1431         SendChannelRangeQuery {
1432                 /// The node_id of this message recipient
1433                 node_id: PublicKey,
1434                 /// The query_channel_range which should be sent.
1435                 msg: msgs::QueryChannelRange,
1436         },
1437         /// Request routing gossip messages from a peer for a list of channels identified by
1438         /// their short_channel_ids.
1439         SendShortIdsQuery {
1440                 /// The node_id of this message recipient
1441                 node_id: PublicKey,
1442                 /// The query_short_channel_ids which should be sent.
1443                 msg: msgs::QueryShortChannelIds,
1444         },
1445         /// Sends a reply to a channel range query. This may be one of several SendReplyChannelRange events
1446         /// emitted during processing of the query.
1447         SendReplyChannelRange {
1448                 /// The node_id of this message recipient
1449                 node_id: PublicKey,
1450                 /// The reply_channel_range which should be sent.
1451                 msg: msgs::ReplyChannelRange,
1452         },
1453         /// Sends a timestamp filter for inbound gossip. This should be sent on each new connection to
1454         /// enable receiving gossip messages from the peer.
1455         SendGossipTimestampFilter {
1456                 /// The node_id of this message recipient
1457                 node_id: PublicKey,
1458                 /// The gossip_timestamp_filter which should be sent.
1459                 msg: msgs::GossipTimestampFilter,
1460         },
1461 }
1462
1463 /// A trait indicating an object may generate message send events
1464 pub trait MessageSendEventsProvider {
1465         /// Gets the list of pending events which were generated by previous actions, clearing the list
1466         /// in the process.
1467         fn get_and_clear_pending_msg_events(&self) -> Vec<MessageSendEvent>;
1468 }
1469
1470 /// A trait indicating an object may generate onion messages to send
1471 pub trait OnionMessageProvider {
1472         /// Gets the next pending onion message for the peer with the given node id.
1473         fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<msgs::OnionMessage>;
1474 }
1475
1476 /// A trait indicating an object may generate events.
1477 ///
1478 /// Events are processed by passing an [`EventHandler`] to [`process_pending_events`].
1479 ///
1480 /// Implementations of this trait may also feature an async version of event handling, as shown with
1481 /// [`ChannelManager::process_pending_events_async`] and
1482 /// [`ChainMonitor::process_pending_events_async`].
1483 ///
1484 /// # Requirements
1485 ///
1486 /// When using this trait, [`process_pending_events`] will call [`handle_event`] for each pending
1487 /// event since the last invocation.
1488 ///
1489 /// In order to ensure no [`Event`]s are lost, implementors of this trait will persist [`Event`]s
1490 /// and replay any unhandled events on startup. An [`Event`] is considered handled when
1491 /// [`process_pending_events`] returns, thus handlers MUST fully handle [`Event`]s and persist any
1492 /// relevant changes to disk *before* returning.
1493 ///
1494 /// Further, because an application may crash between an [`Event`] being handled and the
1495 /// implementor of this trait being re-serialized, [`Event`] handling must be idempotent - in
1496 /// effect, [`Event`]s may be replayed.
1497 ///
1498 /// Note, handlers may call back into the provider and thus deadlocking must be avoided. Be sure to
1499 /// consult the provider's documentation on the implication of processing events and how a handler
1500 /// may safely use the provider (e.g., see [`ChannelManager::process_pending_events`] and
1501 /// [`ChainMonitor::process_pending_events`]).
1502 ///
1503 /// (C-not implementable) As there is likely no reason for a user to implement this trait on their
1504 /// own type(s).
1505 ///
1506 /// [`process_pending_events`]: Self::process_pending_events
1507 /// [`handle_event`]: EventHandler::handle_event
1508 /// [`ChannelManager::process_pending_events`]: crate::ln::channelmanager::ChannelManager#method.process_pending_events
1509 /// [`ChainMonitor::process_pending_events`]: crate::chain::chainmonitor::ChainMonitor#method.process_pending_events
1510 /// [`ChannelManager::process_pending_events_async`]: crate::ln::channelmanager::ChannelManager::process_pending_events_async
1511 /// [`ChainMonitor::process_pending_events_async`]: crate::chain::chainmonitor::ChainMonitor::process_pending_events_async
1512 pub trait EventsProvider {
1513         /// Processes any events generated since the last call using the given event handler.
1514         ///
1515         /// See the trait-level documentation for requirements.
1516         fn process_pending_events<H: Deref>(&self, handler: H) where H::Target: EventHandler;
1517 }
1518
1519 /// A trait implemented for objects handling events from [`EventsProvider`].
1520 ///
1521 /// An async variation also exists for implementations of [`EventsProvider`] that support async
1522 /// event handling. The async event handler should satisfy the generic bounds: `F:
1523 /// core::future::Future, H: Fn(Event) -> F`.
1524 pub trait EventHandler {
1525         /// Handles the given [`Event`].
1526         ///
1527         /// See [`EventsProvider`] for details that must be considered when implementing this method.
1528         fn handle_event(&self, event: Event);
1529 }
1530
1531 impl<F> EventHandler for F where F: Fn(Event) {
1532         fn handle_event(&self, event: Event) {
1533                 self(event)
1534         }
1535 }
1536
1537 impl<T: EventHandler> EventHandler for Arc<T> {
1538         fn handle_event(&self, event: Event) {
1539                 self.deref().handle_event(event)
1540         }
1541 }