git.bitcoin.ninja Git - rust-lightning/blob - lightning/src/util/events.rs

   1 // This file is Copyright its original authors, visible in version control
   2 // history.
   3 //
   4 // This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
   5 // or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
   7 // You may not use this file except in accordance with one or both of these
   8 // licenses.
   9
  10 //! Events are returned from various bits in the library which indicate some action must be taken
  11 //! by the client.
  12 //!
  13 //! Because we don't have a built-in runtime, it's up to the client to call events at a time in the
  14 //! future, as well as generate and broadcast funding transactions handle payment preimages and a
  15 //! few other things.
  16
  17 use crate::chain::keysinterface::SpendableOutputDescriptor;
  18 #[cfg(anchors)]
  19 use crate::ln::chan_utils::HTLCOutputInCommitment;
  20 use crate::ln::channelmanager::{InterceptId, PaymentId};
  21 use crate::ln::channel::FUNDING_CONF_DEADLINE_BLOCKS;
  22 use crate::ln::features::ChannelTypeFeatures;
  23 use crate::ln::msgs;
  24 use crate::ln::msgs::DecodeError;
  25 use crate::ln::{PaymentPreimage, PaymentHash, PaymentSecret};
  26 use crate::routing::gossip::NetworkUpdate;
  27 use crate::util::ser::{BigSize, FixedLengthReader, Writeable, Writer, MaybeReadable, Readable, WithoutLength, OptionDeserWrapper};
  28 use crate::routing::router::{RouteHop, RouteParameters};
  29
  30 use bitcoin::{PackedLockTime, Transaction};
  31 #[cfg(anchors)]
  32 use bitcoin::OutPoint;
  33 use bitcoin::blockdata::script::Script;
  34 use bitcoin::hashes::Hash;
  35 use bitcoin::hashes::sha256::Hash as Sha256;
  36 use bitcoin::secp256k1::PublicKey;
  37 use crate::io;
  38 use crate::prelude::*;
  39 use core::time::Duration;
  40 use core::ops::Deref;
  41 use crate::sync::Arc;
  42
  43 /// Some information provided on receipt of payment depends on whether the payment received is a
  44 /// spontaneous payment or a "conventional" lightning payment that's paying an invoice.
  45 #[derive(Clone, Debug)]
  46 pub enum PaymentPurpose {
  47         /// Information for receiving a payment that we generated an invoice for.
  48         InvoicePayment {
  49                 /// The preimage to the payment_hash, if the payment hash (and secret) were fetched via
  50                 /// [`ChannelManager::create_inbound_payment`]. If provided, this can be handed directly to
  51                 /// [`ChannelManager::claim_funds`].
  52                 ///
  53                 /// [`ChannelManager::create_inbound_payment`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment
  54                 /// [`ChannelManager::claim_funds`]: crate::ln::channelmanager::ChannelManager::claim_funds
  55                 payment_preimage: Option<PaymentPreimage>,
  56                 /// The "payment secret". This authenticates the sender to the recipient, preventing a
  57                 /// number of deanonymization attacks during the routing process.
  58                 /// It is provided here for your reference, however its accuracy is enforced directly by
  59                 /// [`ChannelManager`] using the values you previously provided to
  60                 /// [`ChannelManager::create_inbound_payment`] or
  61                 /// [`ChannelManager::create_inbound_payment_for_hash`].
  62                 ///
  63                 /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
  64                 /// [`ChannelManager::create_inbound_payment`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment
  65                 /// [`ChannelManager::create_inbound_payment_for_hash`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment_for_hash
  66                 payment_secret: PaymentSecret,
  67         },
  68         /// Because this is a spontaneous payment, the payer generated their own preimage rather than us
  69         /// (the payee) providing a preimage.
  70         SpontaneousPayment(PaymentPreimage),
  71 }
  72
  73 impl_writeable_tlv_based_enum!(PaymentPurpose,
  74         (0, InvoicePayment) => {
  75                 (0, payment_preimage, option),
  76                 (2, payment_secret, required),
  77         };
  78         (2, SpontaneousPayment)
  79 );
  80
  81 #[derive(Clone, Debug, PartialEq, Eq)]
  82 /// The reason the channel was closed. See individual variants more details.
  83 pub enum ClosureReason {
  84         /// Closure generated from receiving a peer error message.
  85         ///
  86         /// Our counterparty may have broadcasted their latest commitment state, and we have
  87         /// as well.
  88         CounterpartyForceClosed {
  89                 /// The error which the peer sent us.
  90                 ///
  91                 /// The string should be sanitized before it is used (e.g emitted to logs
  92                 /// or printed to stdout). Otherwise, a well crafted error message may exploit
  93                 /// a security vulnerability in the terminal emulator or the logging subsystem.
  94                 peer_msg: String,
  95         },
  96         /// Closure generated from [`ChannelManager::force_close_channel`], called by the user.
  97         ///
  98         /// [`ChannelManager::force_close_channel`]: crate::ln::channelmanager::ChannelManager::force_close_channel.
  99         HolderForceClosed,
 100         /// The channel was closed after negotiating a cooperative close and we've now broadcasted
 101         /// the cooperative close transaction. Note the shutdown may have been initiated by us.
 102         //TODO: split between CounterpartyInitiated/LocallyInitiated
 103         CooperativeClosure,
 104         /// A commitment transaction was confirmed on chain, closing the channel. Most likely this
 105         /// commitment transaction came from our counterparty, but it may also have come from
 106         /// a copy of our own `ChannelMonitor`.
 107         CommitmentTxConfirmed,
 108         /// The funding transaction failed to confirm in a timely manner on an inbound channel.
 109         FundingTimedOut,
 110         /// Closure generated from processing an event, likely a HTLC forward/relay/reception.
 111         ProcessingError {
 112                 /// A developer-readable error message which we generated.
 113                 err: String,
 114         },
 115         /// The peer disconnected prior to funding completing. In this case the spec mandates that we
 116         /// forget the channel entirely - we can attempt again if the peer reconnects.
 117         ///
 118         /// This includes cases where we restarted prior to funding completion, including prior to the
 119         /// initial [`ChannelMonitor`] persistence completing.
 120         ///
 121         /// In LDK versions prior to 0.0.107 this could also occur if we were unable to connect to the
 122         /// peer because of mutual incompatibility between us and our channel counterparty.
 123         ///
 124         /// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
 125         DisconnectedPeer,
 126         /// Closure generated from `ChannelManager::read` if the [`ChannelMonitor`] is newer than
 127         /// the [`ChannelManager`] deserialized.
 128         ///
 129         /// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
 130         /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
 131         OutdatedChannelManager
 132 }
 133
 134 impl core::fmt::Display for ClosureReason {
 135         fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
 136                 f.write_str("Channel closed because ")?;
 137                 match self {
 138                         ClosureReason::CounterpartyForceClosed { peer_msg } => {
 139                                 f.write_str("counterparty force-closed with message ")?;
 140                                 f.write_str(&peer_msg)
 141                         },
 142                         ClosureReason::HolderForceClosed => f.write_str("user manually force-closed the channel"),
 143                         ClosureReason::CooperativeClosure => f.write_str("the channel was cooperatively closed"),
 144                         ClosureReason::CommitmentTxConfirmed => f.write_str("commitment or closing transaction was confirmed on chain."),
 145                         ClosureReason::FundingTimedOut => write!(f, "funding transaction failed to confirm within {} blocks", FUNDING_CONF_DEADLINE_BLOCKS),
 146                         ClosureReason::ProcessingError { err } => {
 147                                 f.write_str("of an exception: ")?;
 148                                 f.write_str(&err)
 149                         },
 150                         ClosureReason::DisconnectedPeer => f.write_str("the peer disconnected prior to the channel being funded"),
 151                         ClosureReason::OutdatedChannelManager => f.write_str("the ChannelManager read from disk was stale compared to ChannelMonitor(s)"),
 152                 }
 153         }
 154 }
 155
 156 impl_writeable_tlv_based_enum_upgradable!(ClosureReason,
 157         (0, CounterpartyForceClosed) => { (1, peer_msg, required) },
 158         (1, FundingTimedOut) => {},
 159         (2, HolderForceClosed) => {},
 160         (6, CommitmentTxConfirmed) => {},
 161         (4, CooperativeClosure) => {},
 162         (8, ProcessingError) => { (1, err, required) },
 163         (10, DisconnectedPeer) => {},
 164         (12, OutdatedChannelManager) => {},
 165 );
 166
 167 /// Intended destination of a failed HTLC as indicated in [`Event::HTLCHandlingFailed`].
 168 #[derive(Clone, Debug, PartialEq, Eq)]
 169 pub enum HTLCDestination {
 170         /// We tried forwarding to a channel but failed to do so. An example of such an instance is when
 171         /// there is insufficient capacity in our outbound channel.
 172         NextHopChannel {
 173                 /// The `node_id` of the next node. For backwards compatibility, this field is
 174                 /// marked as optional, versions prior to 0.0.110 may not always be able to provide
 175                 /// counterparty node information.
 176                 node_id: Option<PublicKey>,
 177                 /// The outgoing `channel_id` between us and the next node.
 178                 channel_id: [u8; 32],
 179         },
 180         /// Scenario where we are unsure of the next node to forward the HTLC to.
 181         UnknownNextHop {
 182                 /// Short channel id we are requesting to forward an HTLC to.
 183                 requested_forward_scid: u64,
 184         },
 185         /// We couldn't forward to the outgoing scid. An example would be attempting to send a duplicate
 186         /// intercept HTLC.
 187         InvalidForward {
 188                 /// Short channel id we are requesting to forward an HTLC to.
 189                 requested_forward_scid: u64
 190         },
 191         /// Failure scenario where an HTLC may have been forwarded to be intended for us,
 192         /// but is invalid for some reason, so we reject it.
 193         ///
 194         /// Some of the reasons may include:
 195         /// * HTLC Timeouts
 196         /// * Expected MPP amount to claim does not equal HTLC total
 197         /// * Claimable amount does not match expected amount
 198         FailedPayment {
 199                 /// The payment hash of the payment we attempted to process.
 200                 payment_hash: PaymentHash
 201         },
 202 }
 203
 204 impl_writeable_tlv_based_enum_upgradable!(HTLCDestination,
 205         (0, NextHopChannel) => {
 206                 (0, node_id, required),
 207                 (2, channel_id, required),
 208         },
 209         (1, InvalidForward) => {
 210                 (0, requested_forward_scid, required),
 211         },
 212         (2, UnknownNextHop) => {
 213                 (0, requested_forward_scid, required),
 214         },
 215         (4, FailedPayment) => {
 216                 (0, payment_hash, required),
 217         },
 218 );
 219
 220 #[cfg(anchors)]
 221 /// A descriptor used to sign for a commitment transaction's anchor output.
 222 #[derive(Clone, Debug)]
 223 pub struct AnchorDescriptor {
 224         /// A unique identifier used along with `channel_value_satoshis` to re-derive the
 225         /// [`InMemorySigner`] required to sign `input`.
 226         ///
 227         /// [`InMemorySigner`]: crate::chain::keysinterface::InMemorySigner
 228         pub channel_keys_id: [u8; 32],
 229         /// The value in satoshis of the channel we're attempting to spend the anchor output of. This is
 230         /// used along with `channel_keys_id` to re-derive the [`InMemorySigner`] required to sign
 231         /// `input`.
 232         ///
 233         /// [`InMemorySigner`]: crate::chain::keysinterface::InMemorySigner
 234         pub channel_value_satoshis: u64,
 235         /// The transaction input's outpoint corresponding to the commitment transaction's anchor
 236         /// output.
 237         pub outpoint: OutPoint,
 238 }
 239
 240 #[cfg(anchors)]
 241 /// Represents the different types of transactions, originating from LDK, to be bumped.
 242 #[derive(Clone, Debug)]
 243 pub enum BumpTransactionEvent {
 244         /// Indicates that a channel featuring anchor outputs is to be closed by broadcasting the local
 245         /// commitment transaction. Since commitment transactions have a static feerate pre-agreed upon,
 246         /// they may need additional fees to be attached through a child transaction using the popular
 247         /// [Child-Pays-For-Parent](https://bitcoinops.org/en/topics/cpfp) fee bumping technique. This
 248         /// child transaction must include the anchor input described within `anchor_descriptor` along
 249         /// with additional inputs to meet the target feerate. Failure to meet the target feerate
 250         /// decreases the confirmation odds of the transaction package (which includes the commitment
 251         /// and child anchor transactions), possibly resulting in a loss of funds. Once the transaction
 252         /// is constructed, it must be fully signed for and broadcasted by the consumer of the event
 253         /// along with the `commitment_tx` enclosed. Note that the `commitment_tx` must always be
 254         /// broadcast first, as the child anchor transaction depends on it.
 255         ///
 256         /// The consumer should be able to sign for any of the additional inputs included within the
 257         /// child anchor transaction. To sign its anchor input, an [`InMemorySigner`] should be
 258         /// re-derived through [`KeysManager::derive_channel_keys`] with the help of
 259         /// [`AnchorDescriptor::channel_keys_id`] and [`AnchorDescriptor::channel_value_satoshis`].
 260         ///
 261         /// It is possible to receive more than one instance of this event if a valid child anchor
 262         /// transaction is never broadcast or is but not with a sufficient fee to be mined. Care should
 263         /// be taken by the consumer of the event to ensure any future iterations of the child anchor
 264         /// transaction adhere to the [Replace-By-Fee
 265         /// rules](https://github.com/bitcoin/bitcoin/blob/master/doc/policy/mempool-replacements.md)
 266         /// for fee bumps to be accepted into the mempool, and eventually the chain. As the frequency of
 267         /// these events is not user-controlled, users may ignore/drop the event if they are no longer
 268         /// able to commit external confirmed funds to the child anchor transaction.
 269         ///
 270         /// The set of `pending_htlcs` on the commitment transaction to be broadcast can be inspected to
 271         /// determine whether a significant portion of the channel's funds are allocated to HTLCs,
 272         /// enabling users to make their own decisions regarding the importance of the commitment
 273         /// transaction's confirmation. Note that this is not required, but simply exists as an option
 274         /// for users to override LDK's behavior. On commitments with no HTLCs (indicated by those with
 275         /// an empty `pending_htlcs`), confirmation of the commitment transaction can be considered to
 276         /// be not urgent.
 277         ///
 278         /// [`InMemorySigner`]: crate::chain::keysinterface::InMemorySigner
 279         /// [`KeysManager::derive_channel_keys`]: crate::chain::keysinterface::KeysManager::derive_channel_keys
 280         ChannelClose {
 281                 /// The target feerate that the transaction package, which consists of the commitment
 282                 /// transaction and the to-be-crafted child anchor transaction, must meet.
 283                 package_target_feerate_sat_per_1000_weight: u32,
 284                 /// The channel's commitment transaction to bump the fee of. This transaction should be
 285                 /// broadcast along with the anchor transaction constructed as a result of consuming this
 286                 /// event.
 287                 commitment_tx: Transaction,
 288                 /// The absolute fee in satoshis of the commitment transaction. This can be used along the
 289                 /// with weight of the commitment transaction to determine its feerate.
 290                 commitment_tx_fee_satoshis: u64,
 291                 /// The descriptor to sign the anchor input of the anchor transaction constructed as a
 292                 /// result of consuming this event.
 293                 anchor_descriptor: AnchorDescriptor,
 294                 /// The set of pending HTLCs on the commitment transaction that need to be resolved once the
 295                 /// commitment transaction confirms.
 296                 pending_htlcs: Vec<HTLCOutputInCommitment>,
 297         },
 298 }
 299
 300 /// Will be used in [`Event::HTLCIntercepted`] to identify the next hop in the HTLC's path.
 301 /// Currently only used in serialization for the sake of maintaining compatibility. More variants
 302 /// will be added for general-purpose HTLC forward intercepts as well as trampoline forward
 303 /// intercepts in upcoming work.
 304 enum InterceptNextHop {
 305         FakeScid {
 306                 requested_next_hop_scid: u64,
 307         },
 308 }
 309
 310 impl_writeable_tlv_based_enum!(InterceptNextHop,
 311         (0, FakeScid) => {
 312                 (0, requested_next_hop_scid, required),
 313         };
 314 );
 315
 316 /// An Event which you should probably take some action in response to.
 317 ///
 318 /// Note that while Writeable and Readable are implemented for Event, you probably shouldn't use
 319 /// them directly as they don't round-trip exactly (for example FundingGenerationReady is never
 320 /// written as it makes no sense to respond to it after reconnecting to peers).
 321 #[derive(Clone, Debug)]
 322 pub enum Event {
 323         /// Used to indicate that the client should generate a funding transaction with the given
 324         /// parameters and then call [`ChannelManager::funding_transaction_generated`].
 325         /// Generated in [`ChannelManager`] message handling.
 326         /// Note that *all inputs* in the funding transaction must spend SegWit outputs or your
 327         /// counterparty can steal your funds!
 328         ///
 329         /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
 330         /// [`ChannelManager::funding_transaction_generated`]: crate::ln::channelmanager::ChannelManager::funding_transaction_generated
 331         FundingGenerationReady {
 332                 /// The random channel_id we picked which you'll need to pass into
 333                 /// [`ChannelManager::funding_transaction_generated`].
 334                 ///
 335                 /// [`ChannelManager::funding_transaction_generated`]: crate::ln::channelmanager::ChannelManager::funding_transaction_generated
 336                 temporary_channel_id: [u8; 32],
 337                 /// The counterparty's node_id, which you'll need to pass back into
 338                 /// [`ChannelManager::funding_transaction_generated`].
 339                 ///
 340                 /// [`ChannelManager::funding_transaction_generated`]: crate::ln::channelmanager::ChannelManager::funding_transaction_generated
 341                 counterparty_node_id: PublicKey,
 342                 /// The value, in satoshis, that the output should have.
 343                 channel_value_satoshis: u64,
 344                 /// The script which should be used in the transaction output.
 345                 output_script: Script,
 346                 /// The `user_channel_id` value passed in to [`ChannelManager::create_channel`], or a
 347                 /// random value for an inbound channel. This may be zero for objects serialized with LDK
 348                 /// versions prior to 0.0.113.
 349                 ///
 350                 /// [`ChannelManager::create_channel`]: crate::ln::channelmanager::ChannelManager::create_channel
 351                 user_channel_id: u128,
 352         },
 353         /// Indicates we've received (an offer of) money! Just gotta dig out that payment preimage and
 354         /// feed it to [`ChannelManager::claim_funds`] to get it....
 355         ///
 356         /// Note that if the preimage is not known, you should call
 357         /// [`ChannelManager::fail_htlc_backwards`] to free up resources for this HTLC and avoid
 358         /// network congestion.
 359         /// If you fail to call either [`ChannelManager::claim_funds`] or
 360         /// [`ChannelManager::fail_htlc_backwards`] within the HTLC's timeout, the HTLC will be
 361         /// automatically failed.
 362         ///
 363         /// # Note
 364         /// LDK will not stop an inbound payment from being paid multiple times, so multiple
 365         /// `PaymentReceived` events may be generated for the same payment.
 366         ///
 367         /// [`ChannelManager::claim_funds`]: crate::ln::channelmanager::ChannelManager::claim_funds
 368         /// [`ChannelManager::fail_htlc_backwards`]: crate::ln::channelmanager::ChannelManager::fail_htlc_backwards
 369         PaymentReceived {
 370                 /// The node that received the payment.
 371                 /// This is useful to identify payments which were received via [phantom node payments].
 372                 /// This field will always be filled in when the event was generated by LDK versions
 373                 /// 0.0.113 and above.
 374                 ///
 375                 /// [phantom node payments]: crate::chain::keysinterface::PhantomKeysManager
 376                 receiver_node_id: Option<PublicKey>,
 377                 /// The hash for which the preimage should be handed to the ChannelManager. Note that LDK will
 378                 /// not stop you from registering duplicate payment hashes for inbound payments.
 379                 payment_hash: PaymentHash,
 380                 /// The value, in thousandths of a satoshi, that this payment is for.
 381                 amount_msat: u64,
 382                 /// Information for claiming this received payment, based on whether the purpose of the
 383                 /// payment is to pay an invoice or to send a spontaneous payment.
 384                 purpose: PaymentPurpose,
 385                 /// The `channel_id` indicating over which channel we received the payment.
 386                 via_channel_id: Option<[u8; 32]>,
 387                 /// The `user_channel_id` indicating over which channel we received the payment.
 388                 via_user_channel_id: Option<u128>,
 389         },
 390         /// Indicates a payment has been claimed and we've received money!
 391         ///
 392         /// This most likely occurs when [`ChannelManager::claim_funds`] has been called in response
 393         /// to an [`Event::PaymentReceived`]. However, if we previously crashed during a
 394         /// [`ChannelManager::claim_funds`] call you may see this event without a corresponding
 395         /// [`Event::PaymentReceived`] event.
 396         ///
 397         /// # Note
 398         /// LDK will not stop an inbound payment from being paid multiple times, so multiple
 399         /// `PaymentReceived` events may be generated for the same payment. If you then call
 400         /// [`ChannelManager::claim_funds`] twice for the same [`Event::PaymentReceived`] you may get
 401         /// multiple `PaymentClaimed` events.
 402         ///
 403         /// [`ChannelManager::claim_funds`]: crate::ln::channelmanager::ChannelManager::claim_funds
 404         PaymentClaimed {
 405                 /// The node that received the payment.
 406                 /// This is useful to identify payments which were received via [phantom node payments].
 407                 /// This field will always be filled in when the event was generated by LDK versions
 408                 /// 0.0.113 and above.
 409                 ///
 410                 /// [phantom node payments]: crate::chain::keysinterface::PhantomKeysManager
 411                 receiver_node_id: Option<PublicKey>,
 412                 /// The payment hash of the claimed payment. Note that LDK will not stop you from
 413                 /// registering duplicate payment hashes for inbound payments.
 414                 payment_hash: PaymentHash,
 415                 /// The value, in thousandths of a satoshi, that this payment is for.
 416                 amount_msat: u64,
 417                 /// The purpose of this claimed payment, i.e. whether the payment was for an invoice or a
 418                 /// spontaneous payment.
 419                 purpose: PaymentPurpose,
 420         },
 421         /// Indicates an outbound payment we made succeeded (i.e. it made it all the way to its target
 422         /// and we got back the payment preimage for it).
 423         ///
 424         /// Note for MPP payments: in rare cases, this event may be preceded by a `PaymentPathFailed`
 425         /// event. In this situation, you SHOULD treat this payment as having succeeded.
 426         PaymentSent {
 427                 /// The id returned by [`ChannelManager::send_payment`] and used with
 428                 /// [`ChannelManager::retry_payment`].
 429                 ///
 430                 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
 431                 /// [`ChannelManager::retry_payment`]: crate::ln::channelmanager::ChannelManager::retry_payment
 432                 payment_id: Option<PaymentId>,
 433                 /// The preimage to the hash given to ChannelManager::send_payment.
 434                 /// Note that this serves as a payment receipt, if you wish to have such a thing, you must
 435                 /// store it somehow!
 436                 payment_preimage: PaymentPreimage,
 437                 /// The hash that was given to [`ChannelManager::send_payment`].
 438                 ///
 439                 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
 440                 payment_hash: PaymentHash,
 441                 /// The total fee which was spent at intermediate hops in this payment, across all paths.
 442                 ///
 443                 /// Note that, like [`Route::get_total_fees`] this does *not* include any potential
 444                 /// overpayment to the recipient node.
 445                 ///
 446                 /// If the recipient or an intermediate node misbehaves and gives us free money, this may
 447                 /// overstate the amount paid, though this is unlikely.
 448                 ///
 449                 /// [`Route::get_total_fees`]: crate::routing::router::Route::get_total_fees
 450                 fee_paid_msat: Option<u64>,
 451         },
 452         /// Indicates an outbound payment failed. Individual [`Event::PaymentPathFailed`] events
 453         /// provide failure information for each MPP part in the payment.
 454         ///
 455         /// This event is provided once there are no further pending HTLCs for the payment and the
 456         /// payment is no longer retryable due to [`ChannelManager::abandon_payment`] having been
 457         /// called for the corresponding payment.
 458         ///
 459         /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
 460         PaymentFailed {
 461                 /// The id returned by [`ChannelManager::send_payment`] and used with
 462                 /// [`ChannelManager::retry_payment`] and [`ChannelManager::abandon_payment`].
 463                 ///
 464                 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
 465                 /// [`ChannelManager::retry_payment`]: crate::ln::channelmanager::ChannelManager::retry_payment
 466                 /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
 467                 payment_id: PaymentId,
 468                 /// The hash that was given to [`ChannelManager::send_payment`].
 469                 ///
 470                 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
 471                 payment_hash: PaymentHash,
 472         },
 473         /// Indicates that a path for an outbound payment was successful.
 474         ///
 475         /// Always generated after [`Event::PaymentSent`] and thus useful for scoring channels. See
 476         /// [`Event::PaymentSent`] for obtaining the payment preimage.
 477         PaymentPathSuccessful {
 478                 /// The id returned by [`ChannelManager::send_payment`] and used with
 479                 /// [`ChannelManager::retry_payment`].
 480                 ///
 481                 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
 482                 /// [`ChannelManager::retry_payment`]: crate::ln::channelmanager::ChannelManager::retry_payment
 483                 payment_id: PaymentId,
 484                 /// The hash that was given to [`ChannelManager::send_payment`].
 485                 ///
 486                 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
 487                 payment_hash: Option<PaymentHash>,
 488                 /// The payment path that was successful.
 489                 ///
 490                 /// May contain a closed channel if the HTLC sent along the path was fulfilled on chain.
 491                 path: Vec<RouteHop>,
 492         },
 493         /// Indicates an outbound HTLC we sent failed. Probably some intermediary node dropped
 494         /// something. You may wish to retry with a different route.
 495         ///
 496         /// If you have given up retrying this payment and wish to fail it, you MUST call
 497         /// [`ChannelManager::abandon_payment`] at least once for a given [`PaymentId`] or memory
 498         /// related to payment tracking will leak.
 499         ///
 500         /// Note that this does *not* indicate that all paths for an MPP payment have failed, see
 501         /// [`Event::PaymentFailed`] and [`all_paths_failed`].
 502         ///
 503         /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
 504         /// [`all_paths_failed`]: Self::PaymentPathFailed::all_paths_failed
 505         PaymentPathFailed {
 506                 /// The id returned by [`ChannelManager::send_payment`] and used with
 507                 /// [`ChannelManager::retry_payment`] and [`ChannelManager::abandon_payment`].
 508                 ///
 509                 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
 510                 /// [`ChannelManager::retry_payment`]: crate::ln::channelmanager::ChannelManager::retry_payment
 511                 /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
 512                 payment_id: Option<PaymentId>,
 513                 /// The hash that was given to [`ChannelManager::send_payment`].
 514                 ///
 515                 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
 516                 payment_hash: PaymentHash,
 517                 /// Indicates the payment was rejected for some reason by the recipient. This implies that
 518                 /// the payment has failed, not just the route in question. If this is not set, you may
 519                 /// retry the payment via a different route.
 520                 payment_failed_permanently: bool,
 521                 /// Any failure information conveyed via the Onion return packet by a node along the failed
 522                 /// payment route.
 523                 ///
 524                 /// Should be applied to the [`NetworkGraph`] so that routing decisions can take into
 525                 /// account the update.
 526                 ///
 527                 /// [`NetworkGraph`]: crate::routing::gossip::NetworkGraph
 528                 network_update: Option<NetworkUpdate>,
 529                 /// For both single-path and multi-path payments, this is set if all paths of the payment have
 530                 /// failed. This will be set to false if (1) this is an MPP payment and (2) other parts of the
 531                 /// larger MPP payment were still in flight when this event was generated.
 532                 ///
 533                 /// Note that if you are retrying individual MPP parts, using this value to determine if a
 534                 /// payment has fully failed is race-y. Because multiple failures can happen prior to events
 535                 /// being processed, you may retry in response to a first failure, with a second failure
 536                 /// (with `all_paths_failed` set) still pending. Then, when the second failure is processed
 537                 /// you will see `all_paths_failed` set even though the retry of the first failure still
 538                 /// has an associated in-flight HTLC. See (1) for an example of such a failure.
 539                 ///
 540                 /// If you wish to retry individual MPP parts and learn when a payment has failed, you must
 541                 /// call [`ChannelManager::abandon_payment`] and wait for a [`Event::PaymentFailed`] event.
 542                 ///
 543                 /// (1) <https://github.com/lightningdevkit/rust-lightning/issues/1164>
 544                 ///
 545                 /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
 546                 all_paths_failed: bool,
 547                 /// The payment path that failed.
 548                 path: Vec<RouteHop>,
 549                 /// The channel responsible for the failed payment path.
 550                 ///
 551                 /// Note that for route hints or for the first hop in a path this may be an SCID alias and
 552                 /// may not refer to a channel in the public network graph. These aliases may also collide
 553                 /// with channels in the public network graph.
 554                 ///
 555                 /// If this is `Some`, then the corresponding channel should be avoided when the payment is
 556                 /// retried. May be `None` for older [`Event`] serializations.
 557                 short_channel_id: Option<u64>,
 558                 /// Parameters needed to compute a new [`Route`] when retrying the failed payment path.
 559                 ///
 560                 /// See [`find_route`] for details.
 561                 ///
 562                 /// [`Route`]: crate::routing::router::Route
 563                 /// [`find_route`]: crate::routing::router::find_route
 564                 retry: Option<RouteParameters>,
 565 #[cfg(test)]
 566                 error_code: Option<u16>,
 567 #[cfg(test)]
 568                 error_data: Option<Vec<u8>>,
 569         },
 570         /// Indicates that a probe payment we sent returned successful, i.e., only failed at the destination.
 571         ProbeSuccessful {
 572                 /// The id returned by [`ChannelManager::send_probe`].
 573                 ///
 574                 /// [`ChannelManager::send_probe`]: crate::ln::channelmanager::ChannelManager::send_probe
 575                 payment_id: PaymentId,
 576                 /// The hash generated by [`ChannelManager::send_probe`].
 577                 ///
 578                 /// [`ChannelManager::send_probe`]: crate::ln::channelmanager::ChannelManager::send_probe
 579                 payment_hash: PaymentHash,
 580                 /// The payment path that was successful.
 581                 path: Vec<RouteHop>,
 582         },
 583         /// Indicates that a probe payment we sent failed at an intermediary node on the path.
 584         ProbeFailed {
 585                 /// The id returned by [`ChannelManager::send_probe`].
 586                 ///
 587                 /// [`ChannelManager::send_probe`]: crate::ln::channelmanager::ChannelManager::send_probe
 588                 payment_id: PaymentId,
 589                 /// The hash generated by [`ChannelManager::send_probe`].
 590                 ///
 591                 /// [`ChannelManager::send_probe`]: crate::ln::channelmanager::ChannelManager::send_probe
 592                 payment_hash: PaymentHash,
 593                 /// The payment path that failed.
 594                 path: Vec<RouteHop>,
 595                 /// The channel responsible for the failed probe.
 596                 ///
 597                 /// Note that for route hints or for the first hop in a path this may be an SCID alias and
 598                 /// may not refer to a channel in the public network graph. These aliases may also collide
 599                 /// with channels in the public network graph.
 600                 short_channel_id: Option<u64>,
 601         },
 602         /// Used to indicate that [`ChannelManager::process_pending_htlc_forwards`] should be called at
 603         /// a time in the future.
 604         ///
 605         /// [`ChannelManager::process_pending_htlc_forwards`]: crate::ln::channelmanager::ChannelManager::process_pending_htlc_forwards
 606         PendingHTLCsForwardable {
 607                 /// The minimum amount of time that should be waited prior to calling
 608                 /// process_pending_htlc_forwards. To increase the effort required to correlate payments,
 609                 /// you should wait a random amount of time in roughly the range (now + time_forwardable,
 610                 /// now + 5*time_forwardable).
 611                 time_forwardable: Duration,
 612         },
 613         /// Used to indicate that we've intercepted an HTLC forward.
 614         HTLCIntercepted {
 615                 /// An id to help LDK identify which HTLC is being forwarded or failed.
 616                 intercept_id: InterceptId,
 617                 /// The fake scid that was programmed as the next hop's scid.
 618                 requested_next_hop_scid: u64,
 619                 /// The payment hash used for this HTLC.
 620                 payment_hash: PaymentHash,
 621                 /// How many msats were received on the inbound edge of this HTLC.
 622                 inbound_amount_msat: u64,
 623                 /// How many msats the payer intended to route to the next node. Depending on the reason you are
 624                 /// intercepting this payment, you might take a fee by forwarding less than this amount.
 625                 ///
 626                 /// Note that LDK will NOT check that expected fees were factored into this value. You MUST
 627                 /// check that whatever fee you want has been included here or subtract it as required. Further,
 628                 /// LDK will not stop you from forwarding more than you received.
 629                 expected_outbound_amount_msat: u64,
 630         },
 631         /// Used to indicate that an output which you should know how to spend was confirmed on chain
 632         /// and is now spendable.
 633         /// Such an output will *not* ever be spent by rust-lightning, and are not at risk of your
 634         /// counterparty spending them due to some kind of timeout. Thus, you need to store them
 635         /// somewhere and spend them when you create on-chain transactions.
 636         SpendableOutputs {
 637                 /// The outputs which you should store as spendable by you.
 638                 outputs: Vec<SpendableOutputDescriptor>,
 639         },
 640         /// This event is generated when a payment has been successfully forwarded through us and a
 641         /// forwarding fee earned.
 642         PaymentForwarded {
 643                 /// The incoming channel between the previous node and us. This is only `None` for events
 644                 /// generated or serialized by versions prior to 0.0.107.
 645                 prev_channel_id: Option<[u8; 32]>,
 646                 /// The outgoing channel between the next node and us. This is only `None` for events
 647                 /// generated or serialized by versions prior to 0.0.107.
 648                 next_channel_id: Option<[u8; 32]>,
 649                 /// The fee, in milli-satoshis, which was earned as a result of the payment.
 650                 ///
 651                 /// Note that if we force-closed the channel over which we forwarded an HTLC while the HTLC
 652                 /// was pending, the amount the next hop claimed will have been rounded down to the nearest
 653                 /// whole satoshi. Thus, the fee calculated here may be higher than expected as we still
 654                 /// claimed the full value in millisatoshis from the source. In this case,
 655                 /// `claim_from_onchain_tx` will be set.
 656                 ///
 657                 /// If the channel which sent us the payment has been force-closed, we will claim the funds
 658                 /// via an on-chain transaction. In that case we do not yet know the on-chain transaction
 659                 /// fees which we will spend and will instead set this to `None`. It is possible duplicate
 660                 /// `PaymentForwarded` events are generated for the same payment iff `fee_earned_msat` is
 661                 /// `None`.
 662                 fee_earned_msat: Option<u64>,
 663                 /// If this is `true`, the forwarded HTLC was claimed by our counterparty via an on-chain
 664                 /// transaction.
 665                 claim_from_onchain_tx: bool,
 666         },
 667         /// Used to indicate that a channel with the given `channel_id` is ready to
 668         /// be used. This event is emitted either when the funding transaction has been confirmed
 669         /// on-chain, or, in case of a 0conf channel, when both parties have confirmed the channel
 670         /// establishment.
 671         ChannelReady {
 672                 /// The channel_id of the channel that is ready.
 673                 channel_id: [u8; 32],
 674                 /// The `user_channel_id` value passed in to [`ChannelManager::create_channel`] for outbound
 675                 /// channels, or to [`ChannelManager::accept_inbound_channel`] for inbound channels if
 676                 /// [`UserConfig::manually_accept_inbound_channels`] config flag is set to true. Otherwise
 677                 /// `user_channel_id` will be randomized for an inbound channel.
 678                 ///
 679                 /// [`ChannelManager::create_channel`]: crate::ln::channelmanager::ChannelManager::create_channel
 680                 /// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
 681                 /// [`UserConfig::manually_accept_inbound_channels`]: crate::util::config::UserConfig::manually_accept_inbound_channels
 682                 user_channel_id: u128,
 683                 /// The node_id of the channel counterparty.
 684                 counterparty_node_id: PublicKey,
 685                 /// The features that this channel will operate with.
 686                 channel_type: ChannelTypeFeatures,
 687         },
 688         /// Used to indicate that a previously opened channel with the given `channel_id` is in the
 689         /// process of closure.
 690         ChannelClosed  {
 691                 /// The channel_id of the channel which has been closed. Note that on-chain transactions
 692                 /// resolving the channel are likely still awaiting confirmation.
 693                 channel_id: [u8; 32],
 694                 /// The `user_channel_id` value passed in to [`ChannelManager::create_channel`] for outbound
 695                 /// channels, or to [`ChannelManager::accept_inbound_channel`] for inbound channels if
 696                 /// [`UserConfig::manually_accept_inbound_channels`] config flag is set to true. Otherwise
 697                 /// `user_channel_id` will be randomized for inbound channels.
 698                 /// This may be zero for inbound channels serialized prior to 0.0.113 and will always be
 699                 /// zero for objects serialized with LDK versions prior to 0.0.102.
 700                 ///
 701                 /// [`ChannelManager::create_channel`]: crate::ln::channelmanager::ChannelManager::create_channel
 702                 /// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
 703                 /// [`UserConfig::manually_accept_inbound_channels`]: crate::util::config::UserConfig::manually_accept_inbound_channels
 704                 user_channel_id: u128,
 705                 /// The reason the channel was closed.
 706                 reason: ClosureReason
 707         },
 708         /// Used to indicate to the user that they can abandon the funding transaction and recycle the
 709         /// inputs for another purpose.
 710         DiscardFunding {
 711                 /// The channel_id of the channel which has been closed.
 712                 channel_id: [u8; 32],
 713                 /// The full transaction received from the user
 714                 transaction: Transaction
 715         },
 716         /// Indicates a request to open a new channel by a peer.
 717         ///
 718         /// To accept the request, call [`ChannelManager::accept_inbound_channel`]. To reject the
 719         /// request, call [`ChannelManager::force_close_without_broadcasting_txn`].
 720         ///
 721         /// The event is only triggered when a new open channel request is received and the
 722         /// [`UserConfig::manually_accept_inbound_channels`] config flag is set to true.
 723         ///
 724         /// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
 725         /// [`ChannelManager::force_close_without_broadcasting_txn`]: crate::ln::channelmanager::ChannelManager::force_close_without_broadcasting_txn
 726         /// [`UserConfig::manually_accept_inbound_channels`]: crate::util::config::UserConfig::manually_accept_inbound_channels
 727         OpenChannelRequest {
 728                 /// The temporary channel ID of the channel requested to be opened.
 729                 ///
 730                 /// When responding to the request, the `temporary_channel_id` should be passed
 731                 /// back to the ChannelManager through [`ChannelManager::accept_inbound_channel`] to accept,
 732                 /// or through [`ChannelManager::force_close_without_broadcasting_txn`] to reject.
 733                 ///
 734                 /// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
 735                 /// [`ChannelManager::force_close_without_broadcasting_txn`]: crate::ln::channelmanager::ChannelManager::force_close_without_broadcasting_txn
 736                 temporary_channel_id: [u8; 32],
 737                 /// The node_id of the counterparty requesting to open the channel.
 738                 ///
 739                 /// When responding to the request, the `counterparty_node_id` should be passed
 740                 /// back to the `ChannelManager` through [`ChannelManager::accept_inbound_channel`] to
 741                 /// accept the request, or through [`ChannelManager::force_close_without_broadcasting_txn`] to reject the
 742                 /// request.
 743                 ///
 744                 /// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
 745                 /// [`ChannelManager::force_close_without_broadcasting_txn`]: crate::ln::channelmanager::ChannelManager::force_close_without_broadcasting_txn
 746                 counterparty_node_id: PublicKey,
 747                 /// The channel value of the requested channel.
 748                 funding_satoshis: u64,
 749                 /// Our starting balance in the channel if the request is accepted, in milli-satoshi.
 750                 push_msat: u64,
 751                 /// The features that this channel will operate with. If you reject the channel, a
 752                 /// well-behaved counterparty may automatically re-attempt the channel with a new set of
 753                 /// feature flags.
 754                 ///
 755                 /// Note that if [`ChannelTypeFeatures::supports_scid_privacy`] returns true on this type,
 756                 /// the resulting [`ChannelManager`] will not be readable by versions of LDK prior to
 757                 /// 0.0.106.
 758                 ///
 759                 /// Furthermore, note that if [`ChannelTypeFeatures::supports_zero_conf`] returns true on this type,
 760                 /// the resulting [`ChannelManager`] will not be readable by versions of LDK prior to
 761                 /// 0.0.107. Channels setting this type also need to get manually accepted via
 762                 /// [`crate::ln::channelmanager::ChannelManager::accept_inbound_channel_from_trusted_peer_0conf`],
 763                 /// or will be rejected otherwise.
 764                 ///
 765                 /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
 766                 channel_type: ChannelTypeFeatures,
 767         },
 768         /// Indicates that the HTLC was accepted, but could not be processed when or after attempting to
 769         /// forward it.
 770         ///
 771         /// Some scenarios where this event may be sent include:
 772         /// * Insufficient capacity in the outbound channel
 773         /// * While waiting to forward the HTLC, the channel it is meant to be forwarded through closes
 774         /// * When an unknown SCID is requested for forwarding a payment.
 775         /// * Claiming an amount for an MPP payment that exceeds the HTLC total
 776         /// * The HTLC has timed out
 777         ///
 778         /// This event, however, does not get generated if an HTLC fails to meet the forwarding
 779         /// requirements (i.e. insufficient fees paid, or a CLTV that is too soon).
 780         HTLCHandlingFailed {
 781                 /// The channel over which the HTLC was received.
 782                 prev_channel_id: [u8; 32],
 783                 /// Destination of the HTLC that failed to be processed.
 784                 failed_next_destination: HTLCDestination,
 785         },
 786         #[cfg(anchors)]
 787         /// Indicates that a transaction originating from LDK needs to have its fee bumped. This event
 788         /// requires confirmed external funds to be readily available to spend.
 789         ///
 790         /// LDK does not currently generate this event. It is limited to the scope of channels with
 791         /// anchor outputs, which will be introduced in a future release.
 792         BumpTransaction(BumpTransactionEvent),
 793 }
 794
 795 impl Writeable for Event {
 796         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 797                 match self {
 798                         &Event::FundingGenerationReady { .. } => {
 799                                 0u8.write(writer)?;
 800                                 // We never write out FundingGenerationReady events as, upon disconnection, peers
 801                                 // drop any channels which have not yet exchanged funding_signed.
 802                         },
 803                         &Event::PaymentReceived { ref payment_hash, ref amount_msat, ref purpose, ref receiver_node_id, ref via_channel_id, ref via_user_channel_id } => {
 804                                 1u8.write(writer)?;
 805                                 let mut payment_secret = None;
 806                                 let payment_preimage;
 807                                 match &purpose {
 808                                         PaymentPurpose::InvoicePayment { payment_preimage: preimage, payment_secret: secret } => {
 809                                                 payment_secret = Some(secret);
 810                                                 payment_preimage = *preimage;
 811                                         },
 812                                         PaymentPurpose::SpontaneousPayment(preimage) => {
 813                                                 payment_preimage = Some(*preimage);
 814                                         }
 815                                 }
 816                                 write_tlv_fields!(writer, {
 817                                         (0, payment_hash, required),
 818                                         (1, receiver_node_id, option),
 819                                         (2, payment_secret, option),
 820                                         (3, via_channel_id, option),
 821                                         (4, amount_msat, required),
 822                                         (5, via_user_channel_id, option),
 823                                         (6, 0u64, required), // user_payment_id required for compatibility with 0.0.103 and earlier
 824                                         (8, payment_preimage, option),
 825                                 });
 826                         },
 827                         &Event::PaymentSent { ref payment_id, ref payment_preimage, ref payment_hash, ref fee_paid_msat } => {
 828                                 2u8.write(writer)?;
 829                                 write_tlv_fields!(writer, {
 830                                         (0, payment_preimage, required),
 831                                         (1, payment_hash, required),
 832                                         (3, payment_id, option),
 833                                         (5, fee_paid_msat, option),
 834                                 });
 835                         },
 836                         &Event::PaymentPathFailed {
 837                                 ref payment_id, ref payment_hash, ref payment_failed_permanently, ref network_update,
 838                                 ref all_paths_failed, ref path, ref short_channel_id, ref retry,
 839                                 #[cfg(test)]
 840                                 ref error_code,
 841                                 #[cfg(test)]
 842                                 ref error_data,
 843                         } => {
 844                                 3u8.write(writer)?;
 845                                 #[cfg(test)]
 846                                 error_code.write(writer)?;
 847                                 #[cfg(test)]
 848                                 error_data.write(writer)?;
 849                                 write_tlv_fields!(writer, {
 850                                         (0, payment_hash, required),
 851                                         (1, network_update, option),
 852                                         (2, payment_failed_permanently, required),
 853                                         (3, all_paths_failed, required),
 854                                         (5, *path, vec_type),
 855                                         (7, short_channel_id, option),
 856                                         (9, retry, option),
 857                                         (11, payment_id, option),
 858                                 });
 859                         },
 860                         &Event::PendingHTLCsForwardable { time_forwardable: _ } => {
 861                                 4u8.write(writer)?;
 862                                 // Note that we now ignore these on the read end as we'll re-generate them in
 863                                 // ChannelManager, we write them here only for backwards compatibility.
 864                         },
 865                         &Event::SpendableOutputs { ref outputs } => {
 866                                 5u8.write(writer)?;
 867                                 write_tlv_fields!(writer, {
 868                                         (0, WithoutLength(outputs), required),
 869                                 });
 870                         },
 871                         &Event::HTLCIntercepted { requested_next_hop_scid, payment_hash, inbound_amount_msat, expected_outbound_amount_msat, intercept_id } => {
 872                                 6u8.write(writer)?;
 873                                 let intercept_scid = InterceptNextHop::FakeScid { requested_next_hop_scid };
 874                                 write_tlv_fields!(writer, {
 875                                         (0, intercept_id, required),
 876                                         (2, intercept_scid, required),
 877                                         (4, payment_hash, required),
 878                                         (6, inbound_amount_msat, required),
 879                                         (8, expected_outbound_amount_msat, required),
 880                                 });
 881                         }
 882                         &Event::PaymentForwarded { fee_earned_msat, prev_channel_id, claim_from_onchain_tx, next_channel_id } => {
 883                                 7u8.write(writer)?;
 884                                 write_tlv_fields!(writer, {
 885                                         (0, fee_earned_msat, option),
 886                                         (1, prev_channel_id, option),
 887                                         (2, claim_from_onchain_tx, required),
 888                                         (3, next_channel_id, option),
 889                                 });
 890                         },
 891                         &Event::ChannelClosed { ref channel_id, ref user_channel_id, ref reason } => {
 892                                 9u8.write(writer)?;
 893                                 // `user_channel_id` used to be a single u64 value. In order to remain backwards
 894                                 // compatible with versions prior to 0.0.113, the u128 is serialized as two
 895                                 // separate u64 values.
 896                                 let user_channel_id_low = *user_channel_id as u64;
 897                                 let user_channel_id_high = (*user_channel_id >> 64) as u64;
 898                                 write_tlv_fields!(writer, {
 899                                         (0, channel_id, required),
 900                                         (1, user_channel_id_low, required),
 901                                         (2, reason, required),
 902                                         (3, user_channel_id_high, required),
 903                                 });
 904                         },
 905                         &Event::DiscardFunding { ref channel_id, ref transaction } => {
 906                                 11u8.write(writer)?;
 907                                 write_tlv_fields!(writer, {
 908                                         (0, channel_id, required),
 909                                         (2, transaction, required)
 910                                 })
 911                         },
 912                         &Event::PaymentPathSuccessful { ref payment_id, ref payment_hash, ref path } => {
 913                                 13u8.write(writer)?;
 914                                 write_tlv_fields!(writer, {
 915                                         (0, payment_id, required),
 916                                         (2, payment_hash, option),
 917                                         (4, *path, vec_type)
 918                                 })
 919                         },
 920                         &Event::PaymentFailed { ref payment_id, ref payment_hash } => {
 921                                 15u8.write(writer)?;
 922                                 write_tlv_fields!(writer, {
 923                                         (0, payment_id, required),
 924                                         (2, payment_hash, required),
 925                                 })
 926                         },
 927                         &Event::OpenChannelRequest { .. } => {
 928                                 17u8.write(writer)?;
 929                                 // We never write the OpenChannelRequest events as, upon disconnection, peers
 930                                 // drop any channels which have not yet exchanged funding_signed.
 931                         },
 932                         &Event::PaymentClaimed { ref payment_hash, ref amount_msat, ref purpose, ref receiver_node_id } => {
 933                                 19u8.write(writer)?;
 934                                 write_tlv_fields!(writer, {
 935                                         (0, payment_hash, required),
 936                                         (1, receiver_node_id, option),
 937                                         (2, purpose, required),
 938                                         (4, amount_msat, required),
 939                                 });
 940                         },
 941                         &Event::ProbeSuccessful { ref payment_id, ref payment_hash, ref path } => {
 942                                 21u8.write(writer)?;
 943                                 write_tlv_fields!(writer, {
 944                                         (0, payment_id, required),
 945                                         (2, payment_hash, required),
 946                                         (4, *path, vec_type)
 947                                 })
 948                         },
 949                         &Event::ProbeFailed { ref payment_id, ref payment_hash, ref path, ref short_channel_id } => {
 950                                 23u8.write(writer)?;
 951                                 write_tlv_fields!(writer, {
 952                                         (0, payment_id, required),
 953                                         (2, payment_hash, required),
 954                                         (4, *path, vec_type),
 955                                         (6, short_channel_id, option),
 956                                 })
 957                         },
 958                         &Event::HTLCHandlingFailed { ref prev_channel_id, ref failed_next_destination } => {
 959                                 25u8.write(writer)?;
 960                                 write_tlv_fields!(writer, {
 961                                         (0, prev_channel_id, required),
 962                                         (2, failed_next_destination, required),
 963                                 })
 964                         },
 965                         #[cfg(anchors)]
 966                         &Event::BumpTransaction(ref event)=> {
 967                                 27u8.write(writer)?;
 968                                 match event {
 969                                         // We never write the ChannelClose events as they'll be replayed upon restarting
 970                                         // anyway if the commitment transaction remains unconfirmed.
 971                                         BumpTransactionEvent::ChannelClose { .. } => {}
 972                                 }
 973                         }
 974                         &Event::ChannelReady { ref channel_id, ref user_channel_id, ref counterparty_node_id, ref channel_type } => {
 975                                 29u8.write(writer)?;
 976                                 write_tlv_fields!(writer, {
 977                                         (0, channel_id, required),
 978                                         (2, user_channel_id, required),
 979                                         (4, counterparty_node_id, required),
 980                                         (6, channel_type, required),
 981                                 });
 982                         },
 983                         // Note that, going forward, all new events must only write data inside of
 984                         // `write_tlv_fields`. Versions 0.0.101+ will ignore odd-numbered events that write
 985                         // data via `write_tlv_fields`.
 986                 }
 987                 Ok(())
 988         }
 989 }
 990 impl MaybeReadable for Event {
 991         fn read<R: io::Read>(reader: &mut R) -> Result<Option<Self>, msgs::DecodeError> {
 992                 match Readable::read(reader)? {
 993                         // Note that we do not write a length-prefixed TLV for FundingGenerationReady events,
 994                         // unlike all other events, thus we return immediately here.
 995                         0u8 => Ok(None),
 996                         1u8 => {
 997                                 let f = || {
 998                                         let mut payment_hash = PaymentHash([0; 32]);
 999                                         let mut payment_preimage = None;
1000                                         let mut payment_secret = None;
1001                                         let mut amount_msat = 0;
1002                                         let mut receiver_node_id = None;
1003                                         let mut _user_payment_id = None::<u64>; // For compatibility with 0.0.103 and earlier
1004                                         let mut via_channel_id = None;
1005                                         let mut via_user_channel_id = None;
1006                                         read_tlv_fields!(reader, {
1007                                                 (0, payment_hash, required),
1008                                                 (1, receiver_node_id, option),
1009                                                 (2, payment_secret, option),
1010                                                 (3, via_channel_id, option),
1011                                                 (4, amount_msat, required),
1012                                                 (5, via_user_channel_id, option),
1013                                                 (6, _user_payment_id, option),
1014                                                 (8, payment_preimage, option),
1015                                         });
1016                                         let purpose = match payment_secret {
1017                                                 Some(secret) => PaymentPurpose::InvoicePayment {
1018                                                         payment_preimage,
1019                                                         payment_secret: secret
1020                                                 },
1021                                                 None if payment_preimage.is_some() => PaymentPurpose::SpontaneousPayment(payment_preimage.unwrap()),
1022                                                 None => return Err(msgs::DecodeError::InvalidValue),
1023                                         };
1024                                         Ok(Some(Event::PaymentReceived {
1025                                                 receiver_node_id,
1026                                                 payment_hash,
1027                                                 amount_msat,
1028                                                 purpose,
1029                                                 via_channel_id,
1030                                                 via_user_channel_id,
1031                                         }))
1032                                 };
1033                                 f()
1034                         },
1035                         2u8 => {
1036                                 let f = || {
1037                                         let mut payment_preimage = PaymentPreimage([0; 32]);
1038                                         let mut payment_hash = None;
1039                                         let mut payment_id = None;
1040                                         let mut fee_paid_msat = None;
1041                                         read_tlv_fields!(reader, {
1042                                                 (0, payment_preimage, required),
1043                                                 (1, payment_hash, option),
1044                                                 (3, payment_id, option),
1045                                                 (5, fee_paid_msat, option),
1046                                         });
1047                                         if payment_hash.is_none() {
1048                                                 payment_hash = Some(PaymentHash(Sha256::hash(&payment_preimage.0[..]).into_inner()));
1049                                         }
1050                                         Ok(Some(Event::PaymentSent {
1051                                                 payment_id,
1052                                                 payment_preimage,
1053                                                 payment_hash: payment_hash.unwrap(),
1054                                                 fee_paid_msat,
1055                                         }))
1056                                 };
1057                                 f()
1058                         },
1059                         3u8 => {
1060                                 let f = || {
1061                                         #[cfg(test)]
1062                                         let error_code = Readable::read(reader)?;
1063                                         #[cfg(test)]
1064                                         let error_data = Readable::read(reader)?;
1065                                         let mut payment_hash = PaymentHash([0; 32]);
1066                                         let mut payment_failed_permanently = false;
1067                                         let mut network_update = None;
1068                                         let mut all_paths_failed = Some(true);
1069                                         let mut path: Option<Vec<RouteHop>> = Some(vec![]);
1070                                         let mut short_channel_id = None;
1071                                         let mut retry = None;
1072                                         let mut payment_id = None;
1073                                         read_tlv_fields!(reader, {
1074                                                 (0, payment_hash, required),
1075                                                 (1, network_update, ignorable),
1076                                                 (2, payment_failed_permanently, required),
1077                                                 (3, all_paths_failed, option),
1078                                                 (5, path, vec_type),
1079                                                 (7, short_channel_id, option),
1080                                                 (9, retry, option),
1081                                                 (11, payment_id, option),
1082                                         });
1083                                         Ok(Some(Event::PaymentPathFailed {
1084                                                 payment_id,
1085                                                 payment_hash,
1086                                                 payment_failed_permanently,
1087                                                 network_update,
1088                                                 all_paths_failed: all_paths_failed.unwrap(),
1089                                                 path: path.unwrap(),
1090                                                 short_channel_id,
1091                                                 retry,
1092                                                 #[cfg(test)]
1093                                                 error_code,
1094                                                 #[cfg(test)]
1095                                                 error_data,
1096                                         }))
1097                                 };
1098                                 f()
1099                         },
1100                         4u8 => Ok(None),
1101                         5u8 => {
1102                                 let f = || {
1103                                         let mut outputs = WithoutLength(Vec::new());
1104                                         read_tlv_fields!(reader, {
1105                                                 (0, outputs, required),
1106                                         });
1107                                         Ok(Some(Event::SpendableOutputs { outputs: outputs.0 }))
1108                                 };
1109                                 f()
1110                         },
1111                         6u8 => {
1112                                 let mut payment_hash = PaymentHash([0; 32]);
1113                                 let mut intercept_id = InterceptId([0; 32]);
1114                                 let mut requested_next_hop_scid = InterceptNextHop::FakeScid { requested_next_hop_scid: 0 };
1115                                 let mut inbound_amount_msat = 0;
1116                                 let mut expected_outbound_amount_msat = 0;
1117                                 read_tlv_fields!(reader, {
1118                                         (0, intercept_id, required),
1119                                         (2, requested_next_hop_scid, required),
1120                                         (4, payment_hash, required),
1121                                         (6, inbound_amount_msat, required),
1122                                         (8, expected_outbound_amount_msat, required),
1123                                 });
1124                                 let next_scid = match requested_next_hop_scid {
1125                                         InterceptNextHop::FakeScid { requested_next_hop_scid: scid } => scid
1126                                 };
1127                                 Ok(Some(Event::HTLCIntercepted {
1128                                         payment_hash,
1129                                         requested_next_hop_scid: next_scid,
1130                                         inbound_amount_msat,
1131                                         expected_outbound_amount_msat,
1132                                         intercept_id,
1133                                 }))
1134                         },
1135                         7u8 => {
1136                                 let f = || {
1137                                         let mut fee_earned_msat = None;
1138                                         let mut prev_channel_id = None;
1139                                         let mut claim_from_onchain_tx = false;
1140                                         let mut next_channel_id = None;
1141                                         read_tlv_fields!(reader, {
1142                                                 (0, fee_earned_msat, option),
1143                                                 (1, prev_channel_id, option),
1144                                                 (2, claim_from_onchain_tx, required),
1145                                                 (3, next_channel_id, option),
1146                                         });
1147                                         Ok(Some(Event::PaymentForwarded { fee_earned_msat, prev_channel_id, claim_from_onchain_tx, next_channel_id }))
1148                                 };
1149                                 f()
1150                         },
1151                         9u8 => {
1152                                 let f = || {
1153                                         let mut channel_id = [0; 32];
1154                                         let mut reason = None;
1155                                         let mut user_channel_id_low_opt: Option<u64> = None;
1156                                         let mut user_channel_id_high_opt: Option<u64> = None;
1157                                         read_tlv_fields!(reader, {
1158                                                 (0, channel_id, required),
1159                                                 (1, user_channel_id_low_opt, option),
1160                                                 (2, reason, ignorable),
1161                                                 (3, user_channel_id_high_opt, option),
1162                                         });
1163                                         if reason.is_none() { return Ok(None); }
1164
1165                                         // `user_channel_id` used to be a single u64 value. In order to remain
1166                                         // backwards compatible with versions prior to 0.0.113, the u128 is serialized
1167                                         // as two separate u64 values.
1168                                         let user_channel_id = (user_channel_id_low_opt.unwrap_or(0) as u128) +
1169                                                 ((user_channel_id_high_opt.unwrap_or(0) as u128) << 64);
1170
1171                                         Ok(Some(Event::ChannelClosed { channel_id, user_channel_id, reason: reason.unwrap() }))
1172                                 };
1173                                 f()
1174                         },
1175                         11u8 => {
1176                                 let f = || {
1177                                         let mut channel_id = [0; 32];
1178                                         let mut transaction = Transaction{ version: 2, lock_time: PackedLockTime::ZERO, input: Vec::new(), output: Vec::new() };
1179                                         read_tlv_fields!(reader, {
1180                                                 (0, channel_id, required),
1181                                                 (2, transaction, required),
1182                                         });
1183                                         Ok(Some(Event::DiscardFunding { channel_id, transaction } ))
1184                                 };
1185                                 f()
1186                         },
1187                         13u8 => {
1188                                 let f = || {
1189                                         let mut payment_id = PaymentId([0; 32]);
1190                                         let mut payment_hash = None;
1191                                         let mut path: Option<Vec<RouteHop>> = Some(vec![]);
1192                                         read_tlv_fields!(reader, {
1193                                                 (0, payment_id, required),
1194                                                 (2, payment_hash, option),
1195                                                 (4, path, vec_type),
1196                                         });
1197                                         Ok(Some(Event::PaymentPathSuccessful {
1198                                                 payment_id,
1199                                                 payment_hash,
1200                                                 path: path.unwrap(),
1201                                         }))
1202                                 };
1203                                 f()
1204                         },
1205                         15u8 => {
1206                                 let f = || {
1207                                         let mut payment_hash = PaymentHash([0; 32]);
1208                                         let mut payment_id = PaymentId([0; 32]);
1209                                         read_tlv_fields!(reader, {
1210                                                 (0, payment_id, required),
1211                                                 (2, payment_hash, required),
1212                                         });
1213                                         Ok(Some(Event::PaymentFailed {
1214                                                 payment_id,
1215                                                 payment_hash,
1216                                         }))
1217                                 };
1218                                 f()
1219                         },
1220                         17u8 => {
1221                                 // Value 17 is used for `Event::OpenChannelRequest`.
1222                                 Ok(None)
1223                         },
1224                         19u8 => {
1225                                 let f = || {
1226                                         let mut payment_hash = PaymentHash([0; 32]);
1227                                         let mut purpose = None;
1228                                         let mut amount_msat = 0;
1229                                         let mut receiver_node_id = None;
1230                                         read_tlv_fields!(reader, {
1231                                                 (0, payment_hash, required),
1232                                                 (1, receiver_node_id, option),
1233                                                 (2, purpose, ignorable),
1234                                                 (4, amount_msat, required),
1235                                         });
1236                                         if purpose.is_none() { return Ok(None); }
1237                                         Ok(Some(Event::PaymentClaimed {
1238                                                 receiver_node_id,
1239                                                 payment_hash,
1240                                                 purpose: purpose.unwrap(),
1241                                                 amount_msat,
1242                                         }))
1243                                 };
1244                                 f()
1245                         },
1246                         21u8 => {
1247                                 let f = || {
1248                                         let mut payment_id = PaymentId([0; 32]);
1249                                         let mut payment_hash = PaymentHash([0; 32]);
1250                                         let mut path: Option<Vec<RouteHop>> = Some(vec![]);
1251                                         read_tlv_fields!(reader, {
1252                                                 (0, payment_id, required),
1253                                                 (2, payment_hash, required),
1254                                                 (4, path, vec_type),
1255                                         });
1256                                         Ok(Some(Event::ProbeSuccessful {
1257                                                 payment_id,
1258                                                 payment_hash,
1259                                                 path: path.unwrap(),
1260                                         }))
1261                                 };
1262                                 f()
1263                         },
1264                         23u8 => {
1265                                 let f = || {
1266                                         let mut payment_id = PaymentId([0; 32]);
1267                                         let mut payment_hash = PaymentHash([0; 32]);
1268                                         let mut path: Option<Vec<RouteHop>> = Some(vec![]);
1269                                         let mut short_channel_id = None;
1270                                         read_tlv_fields!(reader, {
1271                                                 (0, payment_id, required),
1272                                                 (2, payment_hash, required),
1273                                                 (4, path, vec_type),
1274                                                 (6, short_channel_id, option),
1275                                         });
1276                                         Ok(Some(Event::ProbeFailed {
1277                                                 payment_id,
1278                                                 payment_hash,
1279                                                 path: path.unwrap(),
1280                                                 short_channel_id,
1281                                         }))
1282                                 };
1283                                 f()
1284                         },
1285                         25u8 => {
1286                                 let f = || {
1287                                         let mut prev_channel_id = [0; 32];
1288                                         let mut failed_next_destination_opt = None;
1289                                         read_tlv_fields!(reader, {
1290                                                 (0, prev_channel_id, required),
1291                                                 (2, failed_next_destination_opt, ignorable),
1292                                         });
1293                                         if let Some(failed_next_destination) = failed_next_destination_opt {
1294                                                 Ok(Some(Event::HTLCHandlingFailed {
1295                                                         prev_channel_id,
1296                                                         failed_next_destination,
1297                                                 }))
1298                                         } else {
1299                                                 // If we fail to read a `failed_next_destination` assume it's because
1300                                                 // `MaybeReadable::read` returned `Ok(None)`, though it's also possible we
1301                                                 // were simply missing the field.
1302                                                 Ok(None)
1303                                         }
1304                                 };
1305                                 f()
1306                         },
1307                         27u8 => Ok(None),
1308                         29u8 => {
1309                                 let f = || {
1310                                         let mut channel_id = [0; 32];
1311                                         let mut user_channel_id: u128 = 0;
1312                                         let mut counterparty_node_id = OptionDeserWrapper(None);
1313                                         let mut channel_type = OptionDeserWrapper(None);
1314                                         read_tlv_fields!(reader, {
1315                                                 (0, channel_id, required),
1316                                                 (2, user_channel_id, required),
1317                                                 (4, counterparty_node_id, required),
1318                                                 (6, channel_type, required),
1319                                         });
1320
1321                                         Ok(Some(Event::ChannelReady {
1322                                                 channel_id,
1323                                                 user_channel_id,
1324                                                 counterparty_node_id: counterparty_node_id.0.unwrap(),
1325                                                 channel_type: channel_type.0.unwrap()
1326                                         }))
1327                                 };
1328                                 f()
1329                         },
1330                         // Versions prior to 0.0.100 did not ignore odd types, instead returning InvalidValue.
1331                         // Version 0.0.100 failed to properly ignore odd types, possibly resulting in corrupt
1332                         // reads.
1333                         x if x % 2 == 1 => {
1334                                 // If the event is of unknown type, assume it was written with `write_tlv_fields`,
1335                                 // which prefixes the whole thing with a length BigSize. Because the event is
1336                                 // odd-type unknown, we should treat it as `Ok(None)` even if it has some TLV
1337                                 // fields that are even. Thus, we avoid using `read_tlv_fields` and simply read
1338                                 // exactly the number of bytes specified, ignoring them entirely.
1339                                 let tlv_len: BigSize = Readable::read(reader)?;
1340                                 FixedLengthReader::new(reader, tlv_len.0)
1341                                         .eat_remaining().map_err(|_| msgs::DecodeError::ShortRead)?;
1342                                 Ok(None)
1343                         },
1344                         _ => Err(msgs::DecodeError::InvalidValue)
1345                 }
1346         }
1347 }
1348
1349 /// An event generated by ChannelManager which indicates a message should be sent to a peer (or
1350 /// broadcast to most peers).
1351 /// These events are handled by PeerManager::process_events if you are using a PeerManager.
1352 #[derive(Clone, Debug)]
1353 pub enum MessageSendEvent {
1354         /// Used to indicate that we've accepted a channel open and should send the accept_channel
1355         /// message provided to the given peer.
1356         SendAcceptChannel {
1357                 /// The node_id of the node which should receive this message
1358                 node_id: PublicKey,
1359                 /// The message which should be sent.
1360                 msg: msgs::AcceptChannel,
1361         },
1362         /// Used to indicate that we've initiated a channel open and should send the open_channel
1363         /// message provided to the given peer.
1364         SendOpenChannel {
1365                 /// The node_id of the node which should receive this message
1366                 node_id: PublicKey,
1367                 /// The message which should be sent.
1368                 msg: msgs::OpenChannel,
1369         },
1370         /// Used to indicate that a funding_created message should be sent to the peer with the given node_id.
1371         SendFundingCreated {
1372                 /// The node_id of the node which should receive this message
1373                 node_id: PublicKey,
1374                 /// The message which should be sent.
1375                 msg: msgs::FundingCreated,
1376         },
1377         /// Used to indicate that a funding_signed message should be sent to the peer with the given node_id.
1378         SendFundingSigned {
1379                 /// The node_id of the node which should receive this message
1380                 node_id: PublicKey,
1381                 /// The message which should be sent.
1382                 msg: msgs::FundingSigned,
1383         },
1384         /// Used to indicate that a channel_ready message should be sent to the peer with the given node_id.
1385         SendChannelReady {
1386                 /// The node_id of the node which should receive these message(s)
1387                 node_id: PublicKey,
1388                 /// The channel_ready message which should be sent.
1389                 msg: msgs::ChannelReady,
1390         },
1391         /// Used to indicate that an announcement_signatures message should be sent to the peer with the given node_id.
1392         SendAnnouncementSignatures {
1393                 /// The node_id of the node which should receive these message(s)
1394                 node_id: PublicKey,
1395                 /// The announcement_signatures message which should be sent.
1396                 msg: msgs::AnnouncementSignatures,
1397         },
1398         /// Used to indicate that a series of HTLC update messages, as well as a commitment_signed
1399         /// message should be sent to the peer with the given node_id.
1400         UpdateHTLCs {
1401                 /// The node_id of the node which should receive these message(s)
1402                 node_id: PublicKey,
1403                 /// The update messages which should be sent. ALL messages in the struct should be sent!
1404                 updates: msgs::CommitmentUpdate,
1405         },
1406         /// Used to indicate that a revoke_and_ack message should be sent to the peer with the given node_id.
1407         SendRevokeAndACK {
1408                 /// The node_id of the node which should receive this message
1409                 node_id: PublicKey,
1410                 /// The message which should be sent.
1411                 msg: msgs::RevokeAndACK,
1412         },
1413         /// Used to indicate that a closing_signed message should be sent to the peer with the given node_id.
1414         SendClosingSigned {
1415                 /// The node_id of the node which should receive this message
1416                 node_id: PublicKey,
1417                 /// The message which should be sent.
1418                 msg: msgs::ClosingSigned,
1419         },
1420         /// Used to indicate that a shutdown message should be sent to the peer with the given node_id.
1421         SendShutdown {
1422                 /// The node_id of the node which should receive this message
1423                 node_id: PublicKey,
1424                 /// The message which should be sent.
1425                 msg: msgs::Shutdown,
1426         },
1427         /// Used to indicate that a channel_reestablish message should be sent to the peer with the given node_id.
1428         SendChannelReestablish {
1429                 /// The node_id of the node which should receive this message
1430                 node_id: PublicKey,
1431                 /// The message which should be sent.
1432                 msg: msgs::ChannelReestablish,
1433         },
1434         /// Used to send a channel_announcement and channel_update to a specific peer, likely on
1435         /// initial connection to ensure our peers know about our channels.
1436         SendChannelAnnouncement {
1437                 /// The node_id of the node which should receive this message
1438                 node_id: PublicKey,
1439                 /// The channel_announcement which should be sent.
1440                 msg: msgs::ChannelAnnouncement,
1441                 /// The followup channel_update which should be sent.
1442                 update_msg: msgs::ChannelUpdate,
1443         },
1444         /// Used to indicate that a channel_announcement and channel_update should be broadcast to all
1445         /// peers (except the peer with node_id either msg.contents.node_id_1 or msg.contents.node_id_2).
1446         ///
1447         /// Note that after doing so, you very likely (unless you did so very recently) want to
1448         /// broadcast a node_announcement (e.g. via [`PeerManager::broadcast_node_announcement`]). This
1449         /// ensures that any nodes which see our channel_announcement also have a relevant
1450         /// node_announcement, including relevant feature flags which may be important for routing
1451         /// through or to us.
1452         ///
1453         /// [`PeerManager::broadcast_node_announcement`]: crate::ln::peer_handler::PeerManager::broadcast_node_announcement
1454         BroadcastChannelAnnouncement {
1455                 /// The channel_announcement which should be sent.
1456                 msg: msgs::ChannelAnnouncement,
1457                 /// The followup channel_update which should be sent.
1458                 update_msg: msgs::ChannelUpdate,
1459         },
1460         /// Used to indicate that a channel_update should be broadcast to all peers.
1461         BroadcastChannelUpdate {
1462                 /// The channel_update which should be sent.
1463                 msg: msgs::ChannelUpdate,
1464         },
1465         /// Used to indicate that a channel_update should be sent to a single peer.
1466         /// In contrast to [`Self::BroadcastChannelUpdate`], this is used when the channel is a
1467         /// private channel and we shouldn't be informing all of our peers of channel parameters.
1468         SendChannelUpdate {
1469                 /// The node_id of the node which should receive this message
1470                 node_id: PublicKey,
1471                 /// The channel_update which should be sent.
1472                 msg: msgs::ChannelUpdate,
1473         },
1474         /// Broadcast an error downstream to be handled
1475         HandleError {
1476                 /// The node_id of the node which should receive this message
1477                 node_id: PublicKey,
1478                 /// The action which should be taken.
1479                 action: msgs::ErrorAction
1480         },
1481         /// Query a peer for channels with funding transaction UTXOs in a block range.
1482         SendChannelRangeQuery {
1483                 /// The node_id of this message recipient
1484                 node_id: PublicKey,
1485                 /// The query_channel_range which should be sent.
1486                 msg: msgs::QueryChannelRange,
1487         },
1488         /// Request routing gossip messages from a peer for a list of channels identified by
1489         /// their short_channel_ids.
1490         SendShortIdsQuery {
1491                 /// The node_id of this message recipient
1492                 node_id: PublicKey,
1493                 /// The query_short_channel_ids which should be sent.
1494                 msg: msgs::QueryShortChannelIds,
1495         },
1496         /// Sends a reply to a channel range query. This may be one of several SendReplyChannelRange events
1497         /// emitted during processing of the query.
1498         SendReplyChannelRange {
1499                 /// The node_id of this message recipient
1500                 node_id: PublicKey,
1501                 /// The reply_channel_range which should be sent.
1502                 msg: msgs::ReplyChannelRange,
1503         },
1504         /// Sends a timestamp filter for inbound gossip. This should be sent on each new connection to
1505         /// enable receiving gossip messages from the peer.
1506         SendGossipTimestampFilter {
1507                 /// The node_id of this message recipient
1508                 node_id: PublicKey,
1509                 /// The gossip_timestamp_filter which should be sent.
1510                 msg: msgs::GossipTimestampFilter,
1511         },
1512 }
1513
1514 /// A trait indicating an object may generate message send events
1515 pub trait MessageSendEventsProvider {
1516         /// Gets the list of pending events which were generated by previous actions, clearing the list
1517         /// in the process.
1518         fn get_and_clear_pending_msg_events(&self) -> Vec<MessageSendEvent>;
1519 }
1520
1521 /// A trait indicating an object may generate onion messages to send
1522 pub trait OnionMessageProvider {
1523         /// Gets the next pending onion message for the peer with the given node id.
1524         fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<msgs::OnionMessage>;
1525 }
1526
1527 /// A trait indicating an object may generate events.
1528 ///
1529 /// Events are processed by passing an [`EventHandler`] to [`process_pending_events`].
1530 ///
1531 /// Implementations of this trait may also feature an async version of event handling, as shown with
1532 /// [`ChannelManager::process_pending_events_async`] and
1533 /// [`ChainMonitor::process_pending_events_async`].
1534 ///
1535 /// # Requirements
1536 ///
1537 /// When using this trait, [`process_pending_events`] will call [`handle_event`] for each pending
1538 /// event since the last invocation.
1539 ///
1540 /// In order to ensure no [`Event`]s are lost, implementors of this trait will persist [`Event`]s
1541 /// and replay any unhandled events on startup. An [`Event`] is considered handled when
1542 /// [`process_pending_events`] returns, thus handlers MUST fully handle [`Event`]s and persist any
1543 /// relevant changes to disk *before* returning.
1544 ///
1545 /// Further, because an application may crash between an [`Event`] being handled and the
1546 /// implementor of this trait being re-serialized, [`Event`] handling must be idempotent - in
1547 /// effect, [`Event`]s may be replayed.
1548 ///
1549 /// Note, handlers may call back into the provider and thus deadlocking must be avoided. Be sure to
1550 /// consult the provider's documentation on the implication of processing events and how a handler
1551 /// may safely use the provider (e.g., see [`ChannelManager::process_pending_events`] and
1552 /// [`ChainMonitor::process_pending_events`]).
1553 ///
1554 /// (C-not implementable) As there is likely no reason for a user to implement this trait on their
1555 /// own type(s).
1556 ///
1557 /// [`process_pending_events`]: Self::process_pending_events
1558 /// [`handle_event`]: EventHandler::handle_event
1559 /// [`ChannelManager::process_pending_events`]: crate::ln::channelmanager::ChannelManager#method.process_pending_events
1560 /// [`ChainMonitor::process_pending_events`]: crate::chain::chainmonitor::ChainMonitor#method.process_pending_events
1561 /// [`ChannelManager::process_pending_events_async`]: crate::ln::channelmanager::ChannelManager::process_pending_events_async
1562 /// [`ChainMonitor::process_pending_events_async`]: crate::chain::chainmonitor::ChainMonitor::process_pending_events_async
1563 pub trait EventsProvider {
1564         /// Processes any events generated since the last call using the given event handler.
1565         ///
1566         /// See the trait-level documentation for requirements.
1567         fn process_pending_events<H: Deref>(&self, handler: H) where H::Target: EventHandler;
1568 }
1569
1570 /// A trait implemented for objects handling events from [`EventsProvider`].
1571 ///
1572 /// An async variation also exists for implementations of [`EventsProvider`] that support async
1573 /// event handling. The async event handler should satisfy the generic bounds: `F:
1574 /// core::future::Future, H: Fn(Event) -> F`.
1575 pub trait EventHandler {
1576         /// Handles the given [`Event`].
1577         ///
1578         /// See [`EventsProvider`] for details that must be considered when implementing this method.
1579         fn handle_event(&self, event: Event);
1580 }
1581
1582 impl<F> EventHandler for F where F: Fn(Event) {
1583         fn handle_event(&self, event: Event) {
1584                 self(event)
1585         }
1586 }
1587
1588 impl<T: EventHandler> EventHandler for Arc<T> {
1589         fn handle_event(&self, event: Event) {
1590                 self.deref().handle_event(event)
1591         }
1592 }