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