_ Git - rust-lightning/blob - lightning/src/events/mod.rs

   1 // This file is Copyright its original authors, visible in version control
   2 // history.
   3 //
   4 // This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
   5 // or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
   7 // You may not use this file except in accordance with one or both of these
   8 // licenses.
   9
  10 //! Events are returned from various bits in the library which indicate some action must be taken
  11 //! by the client.
  12 //!
  13 //! Because we don't have a built-in runtime, it's up to the client to call events at a time in the
  14 //! future, as well as generate and broadcast funding transactions handle payment preimages and a
  15 //! few other things.
  16
  17 #[cfg(anchors)]
  18 pub mod bump_transaction;
  19
  20 #[cfg(anchors)]
  21 pub use bump_transaction::BumpTransactionEvent;
  22
  23 use crate::sign::SpendableOutputDescriptor;
  24 use crate::ln::channelmanager::{InterceptId, PaymentId, RecipientOnionFields};
  25 use crate::ln::channel::FUNDING_CONF_DEADLINE_BLOCKS;
  26 use crate::ln::features::ChannelTypeFeatures;
  27 use crate::ln::msgs;
  28 use crate::ln::{PaymentPreimage, PaymentHash, PaymentSecret};
  29 use crate::routing::gossip::NetworkUpdate;
  30 use crate::util::errors::APIError;
  31 use crate::util::ser::{BigSize, FixedLengthReader, Writeable, Writer, MaybeReadable, Readable, RequiredWrapper, UpgradableRequired, WithoutLength};
  32 use crate::util::string::UntrustedString;
  33 use crate::routing::router::{BlindedTail, Path, RouteHop, RouteParameters};
  34
  35 use bitcoin::{PackedLockTime, Transaction, OutPoint};
  36 #[cfg(anchors)]
  37 use bitcoin::{Txid, TxIn, TxOut, Witness};
  38 use bitcoin::blockdata::script::Script;
  39 use bitcoin::hashes::Hash;
  40 use bitcoin::hashes::sha256::Hash as Sha256;
  41 use bitcoin::secp256k1::PublicKey;
  42 use crate::io;
  43 use crate::prelude::*;
  44 use core::time::Duration;
  45 use core::ops::Deref;
  46 use crate::sync::Arc;
  47
  48 /// Some information provided on receipt of payment depends on whether the payment received is a
  49 /// spontaneous payment or a "conventional" lightning payment that's paying an invoice.
  50 #[derive(Clone, Debug, PartialEq, Eq)]
  51 pub enum PaymentPurpose {
  52         /// Information for receiving a payment that we generated an invoice for.
  53         InvoicePayment {
  54                 /// The preimage to the payment_hash, if the payment hash (and secret) were fetched via
  55                 /// [`ChannelManager::create_inbound_payment`]. If provided, this can be handed directly to
  56                 /// [`ChannelManager::claim_funds`].
  57                 ///
  58                 /// [`ChannelManager::create_inbound_payment`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment
  59                 /// [`ChannelManager::claim_funds`]: crate::ln::channelmanager::ChannelManager::claim_funds
  60                 payment_preimage: Option<PaymentPreimage>,
  61                 /// The "payment secret". This authenticates the sender to the recipient, preventing a
  62                 /// number of deanonymization attacks during the routing process.
  63                 /// It is provided here for your reference, however its accuracy is enforced directly by
  64                 /// [`ChannelManager`] using the values you previously provided to
  65                 /// [`ChannelManager::create_inbound_payment`] or
  66                 /// [`ChannelManager::create_inbound_payment_for_hash`].
  67                 ///
  68                 /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
  69                 /// [`ChannelManager::create_inbound_payment`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment
  70                 /// [`ChannelManager::create_inbound_payment_for_hash`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment_for_hash
  71                 payment_secret: PaymentSecret,
  72         },
  73         /// Because this is a spontaneous payment, the payer generated their own preimage rather than us
  74         /// (the payee) providing a preimage.
  75         SpontaneousPayment(PaymentPreimage),
  76 }
  77
  78 impl_writeable_tlv_based_enum!(PaymentPurpose,
  79         (0, InvoicePayment) => {
  80                 (0, payment_preimage, option),
  81                 (2, payment_secret, required),
  82         };
  83         (2, SpontaneousPayment)
  84 );
  85
  86 /// When the payment path failure took place and extra details about it. [`PathFailure::OnPath`] may
  87 /// contain a [`NetworkUpdate`] that needs to be applied to the [`NetworkGraph`].
  88 ///
  89 /// [`NetworkUpdate`]: crate::routing::gossip::NetworkUpdate
  90 /// [`NetworkGraph`]: crate::routing::gossip::NetworkGraph
  91 #[derive(Clone, Debug, Eq, PartialEq)]
  92 pub enum PathFailure {
  93         /// We failed to initially send the payment and no HTLC was committed to. Contains the relevant
  94         /// error.
  95         InitialSend {
  96                 /// The error surfaced from initial send.
  97                 err: APIError,
  98         },
  99         /// A hop on the path failed to forward our payment.
 100         OnPath {
 101                 /// If present, this [`NetworkUpdate`] should be applied to the [`NetworkGraph`] so that routing
 102                 /// decisions can take into account the update.
 103                 ///
 104                 /// [`NetworkUpdate`]: crate::routing::gossip::NetworkUpdate
 105                 /// [`NetworkGraph`]: crate::routing::gossip::NetworkGraph
 106                 network_update: Option<NetworkUpdate>,
 107         },
 108 }
 109
 110 impl_writeable_tlv_based_enum_upgradable!(PathFailure,
 111         (0, OnPath) => {
 112                 (0, network_update, upgradable_option),
 113         },
 114         (2, InitialSend) => {
 115                 (0, err, upgradable_required),
 116         },
 117 );
 118
 119 #[derive(Clone, Debug, PartialEq, Eq)]
 120 /// The reason the channel was closed. See individual variants more details.
 121 pub enum ClosureReason {
 122         /// Closure generated from receiving a peer error message.
 123         ///
 124         /// Our counterparty may have broadcasted their latest commitment state, and we have
 125         /// as well.
 126         CounterpartyForceClosed {
 127                 /// The error which the peer sent us.
 128                 ///
 129                 /// Be careful about printing the peer_msg, a well-crafted message could exploit
 130                 /// a security vulnerability in the terminal emulator or the logging subsystem.
 131                 /// To be safe, use `Display` on `UntrustedString`
 132                 ///
 133                 /// [`UntrustedString`]: crate::util::string::UntrustedString
 134                 peer_msg: UntrustedString,
 135         },
 136         /// Closure generated from [`ChannelManager::force_close_channel`], called by the user.
 137         ///
 138         /// [`ChannelManager::force_close_channel`]: crate::ln::channelmanager::ChannelManager::force_close_channel.
 139         HolderForceClosed,
 140         /// The channel was closed after negotiating a cooperative close and we've now broadcasted
 141         /// the cooperative close transaction. Note the shutdown may have been initiated by us.
 142         //TODO: split between CounterpartyInitiated/LocallyInitiated
 143         CooperativeClosure,
 144         /// A commitment transaction was confirmed on chain, closing the channel. Most likely this
 145         /// commitment transaction came from our counterparty, but it may also have come from
 146         /// a copy of our own `ChannelMonitor`.
 147         CommitmentTxConfirmed,
 148         /// The funding transaction failed to confirm in a timely manner on an inbound channel.
 149         FundingTimedOut,
 150         /// Closure generated from processing an event, likely a HTLC forward/relay/reception.
 151         ProcessingError {
 152                 /// A developer-readable error message which we generated.
 153                 err: String,
 154         },
 155         /// The peer disconnected prior to funding completing. In this case the spec mandates that we
 156         /// forget the channel entirely - we can attempt again if the peer reconnects.
 157         ///
 158         /// This includes cases where we restarted prior to funding completion, including prior to the
 159         /// initial [`ChannelMonitor`] persistence completing.
 160         ///
 161         /// In LDK versions prior to 0.0.107 this could also occur if we were unable to connect to the
 162         /// peer because of mutual incompatibility between us and our channel counterparty.
 163         ///
 164         /// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
 165         DisconnectedPeer,
 166         /// Closure generated from `ChannelManager::read` if the [`ChannelMonitor`] is newer than
 167         /// the [`ChannelManager`] deserialized.
 168         ///
 169         /// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
 170         /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
 171         OutdatedChannelManager
 172 }
 173
 174 impl core::fmt::Display for ClosureReason {
 175         fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
 176                 f.write_str("Channel closed because ")?;
 177                 match self {
 178                         ClosureReason::CounterpartyForceClosed { peer_msg } => {
 179                                 f.write_fmt(format_args!("counterparty force-closed with message: {}", peer_msg))
 180                         },
 181                         ClosureReason::HolderForceClosed => f.write_str("user manually force-closed the channel"),
 182                         ClosureReason::CooperativeClosure => f.write_str("the channel was cooperatively closed"),
 183                         ClosureReason::CommitmentTxConfirmed => f.write_str("commitment or closing transaction was confirmed on chain."),
 184                         ClosureReason::FundingTimedOut => write!(f, "funding transaction failed to confirm within {} blocks", FUNDING_CONF_DEADLINE_BLOCKS),
 185                         ClosureReason::ProcessingError { err } => {
 186                                 f.write_str("of an exception: ")?;
 187                                 f.write_str(&err)
 188                         },
 189                         ClosureReason::DisconnectedPeer => f.write_str("the peer disconnected prior to the channel being funded"),
 190                         ClosureReason::OutdatedChannelManager => f.write_str("the ChannelManager read from disk was stale compared to ChannelMonitor(s)"),
 191                 }
 192         }
 193 }
 194
 195 impl_writeable_tlv_based_enum_upgradable!(ClosureReason,
 196         (0, CounterpartyForceClosed) => { (1, peer_msg, required) },
 197         (1, FundingTimedOut) => {},
 198         (2, HolderForceClosed) => {},
 199         (6, CommitmentTxConfirmed) => {},
 200         (4, CooperativeClosure) => {},
 201         (8, ProcessingError) => { (1, err, required) },
 202         (10, DisconnectedPeer) => {},
 203         (12, OutdatedChannelManager) => {},
 204 );
 205
 206 /// Intended destination of a failed HTLC as indicated in [`Event::HTLCHandlingFailed`].
 207 #[derive(Clone, Debug, PartialEq, Eq)]
 208 pub enum HTLCDestination {
 209         /// We tried forwarding to a channel but failed to do so. An example of such an instance is when
 210         /// there is insufficient capacity in our outbound channel.
 211         NextHopChannel {
 212                 /// The `node_id` of the next node. For backwards compatibility, this field is
 213                 /// marked as optional, versions prior to 0.0.110 may not always be able to provide
 214                 /// counterparty node information.
 215                 node_id: Option<PublicKey>,
 216                 /// The outgoing `channel_id` between us and the next node.
 217                 channel_id: [u8; 32],
 218         },
 219         /// Scenario where we are unsure of the next node to forward the HTLC to.
 220         UnknownNextHop {
 221                 /// Short channel id we are requesting to forward an HTLC to.
 222                 requested_forward_scid: u64,
 223         },
 224         /// We couldn't forward to the outgoing scid. An example would be attempting to send a duplicate
 225         /// intercept HTLC.
 226         InvalidForward {
 227                 /// Short channel id we are requesting to forward an HTLC to.
 228                 requested_forward_scid: u64
 229         },
 230         /// Failure scenario where an HTLC may have been forwarded to be intended for us,
 231         /// but is invalid for some reason, so we reject it.
 232         ///
 233         /// Some of the reasons may include:
 234         /// * HTLC Timeouts
 235         /// * Excess HTLCs for a payment that we have already fully received, over-paying for the
 236         ///   payment,
 237         /// * The counterparty node modified the HTLC in transit,
 238         /// * A probing attack where an intermediary node is trying to detect if we are the ultimate
 239         ///   recipient for a payment.
 240         FailedPayment {
 241                 /// The payment hash of the payment we attempted to process.
 242                 payment_hash: PaymentHash
 243         },
 244 }
 245
 246 impl_writeable_tlv_based_enum_upgradable!(HTLCDestination,
 247         (0, NextHopChannel) => {
 248                 (0, node_id, required),
 249                 (2, channel_id, required),
 250         },
 251         (1, InvalidForward) => {
 252                 (0, requested_forward_scid, required),
 253         },
 254         (2, UnknownNextHop) => {
 255                 (0, requested_forward_scid, required),
 256         },
 257         (4, FailedPayment) => {
 258                 (0, payment_hash, required),
 259         },
 260 );
 261
 262 /// Will be used in [`Event::HTLCIntercepted`] to identify the next hop in the HTLC's path.
 263 /// Currently only used in serialization for the sake of maintaining compatibility. More variants
 264 /// will be added for general-purpose HTLC forward intercepts as well as trampoline forward
 265 /// intercepts in upcoming work.
 266 enum InterceptNextHop {
 267         FakeScid {
 268                 requested_next_hop_scid: u64,
 269         },
 270 }
 271
 272 impl_writeable_tlv_based_enum!(InterceptNextHop,
 273         (0, FakeScid) => {
 274                 (0, requested_next_hop_scid, required),
 275         };
 276 );
 277
 278 /// The reason the payment failed. Used in [`Event::PaymentFailed`].
 279 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 280 pub enum PaymentFailureReason {
 281         /// The intended recipient rejected our payment.
 282         RecipientRejected,
 283         /// The user chose to abandon this payment by calling [`ChannelManager::abandon_payment`].
 284         ///
 285         /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
 286         UserAbandoned,
 287         /// We exhausted all of our retry attempts while trying to send the payment, or we
 288         /// exhausted the [`Retry::Timeout`] if the user set one. If at any point a retry
 289         /// attempt failed while being forwarded along the path, an [`Event::PaymentPathFailed`] will
 290         /// have come before this.
 291         ///
 292         /// [`Retry::Timeout`]: crate::ln::channelmanager::Retry::Timeout
 293         RetriesExhausted,
 294         /// The payment expired while retrying, based on the provided
 295         /// [`PaymentParameters::expiry_time`].
 296         ///
 297         /// [`PaymentParameters::expiry_time`]: crate::routing::router::PaymentParameters::expiry_time
 298         PaymentExpired,
 299         /// We failed to find a route while retrying the payment.
 300         RouteNotFound,
 301         /// This error should generally never happen. This likely means that there is a problem with
 302         /// your router.
 303         UnexpectedError,
 304 }
 305
 306 impl_writeable_tlv_based_enum!(PaymentFailureReason,
 307         (0, RecipientRejected) => {},
 308         (2, UserAbandoned) => {},
 309         (4, RetriesExhausted) => {},
 310         (6, PaymentExpired) => {},
 311         (8, RouteNotFound) => {},
 312         (10, UnexpectedError) => {}, ;
 313 );
 314
 315 /// An Event which you should probably take some action in response to.
 316 ///
 317 /// Note that while Writeable and Readable are implemented for Event, you probably shouldn't use
 318 /// them directly as they don't round-trip exactly (for example FundingGenerationReady is never
 319 /// written as it makes no sense to respond to it after reconnecting to peers).
 320 #[derive(Clone, Debug, PartialEq, Eq)]
 321 pub enum Event {
 322         /// Used to indicate that the client should generate a funding transaction with the given
 323         /// parameters and then call [`ChannelManager::funding_transaction_generated`].
 324         /// Generated in [`ChannelManager`] message handling.
 325         /// Note that *all inputs* in the funding transaction must spend SegWit outputs or your
 326         /// counterparty can steal your funds!
 327         ///
 328         /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
 329         /// [`ChannelManager::funding_transaction_generated`]: crate::ln::channelmanager::ChannelManager::funding_transaction_generated
 330         FundingGenerationReady {
 331                 /// The random channel_id we picked which you'll need to pass into
 332                 /// [`ChannelManager::funding_transaction_generated`].
 333                 ///
 334                 /// [`ChannelManager::funding_transaction_generated`]: crate::ln::channelmanager::ChannelManager::funding_transaction_generated
 335                 temporary_channel_id: [u8; 32],
 336                 /// The counterparty's node_id, which you'll need to pass back into
 337                 /// [`ChannelManager::funding_transaction_generated`].
 338                 ///
 339                 /// [`ChannelManager::funding_transaction_generated`]: crate::ln::channelmanager::ChannelManager::funding_transaction_generated
 340                 counterparty_node_id: PublicKey,
 341                 /// The value, in satoshis, that the output should have.
 342                 channel_value_satoshis: u64,
 343                 /// The script which should be used in the transaction output.
 344                 output_script: Script,
 345                 /// The `user_channel_id` value passed in to [`ChannelManager::create_channel`], or a
 346                 /// random value for an inbound channel. This may be zero for objects serialized with LDK
 347                 /// versions prior to 0.0.113.
 348                 ///
 349                 /// [`ChannelManager::create_channel`]: crate::ln::channelmanager::ChannelManager::create_channel
 350                 user_channel_id: u128,
 351         },
 352         /// Indicates that we've been offered a payment and it needs to be claimed via calling
 353         /// [`ChannelManager::claim_funds`] with the preimage given in [`PaymentPurpose`].
 354         ///
 355         /// Note that if the preimage is not known, you should call
 356         /// [`ChannelManager::fail_htlc_backwards`] or [`ChannelManager::fail_htlc_backwards_with_reason`]
 357         /// to free up resources for this HTLC and avoid network congestion.
 358         /// If you fail to call either [`ChannelManager::claim_funds`], [`ChannelManager::fail_htlc_backwards`],
 359         /// or [`ChannelManager::fail_htlc_backwards_with_reason`] within the HTLC's timeout, the HTLC will be
 360         /// automatically failed.
 361         ///
 362         /// # Note
 363         /// LDK will not stop an inbound payment from being paid multiple times, so multiple
 364         /// `PaymentClaimable` events may be generated for the same payment. In such a case it is
 365         /// polite (and required in the lightning specification) to fail the payment the second time
 366         /// and give the sender their money back rather than accepting double payment.
 367         ///
 368         /// # Note
 369         /// This event used to be called `PaymentReceived` in LDK versions 0.0.112 and earlier.
 370         ///
 371         /// [`ChannelManager::claim_funds`]: crate::ln::channelmanager::ChannelManager::claim_funds
 372         /// [`ChannelManager::fail_htlc_backwards`]: crate::ln::channelmanager::ChannelManager::fail_htlc_backwards
 373         /// [`ChannelManager::fail_htlc_backwards_with_reason`]: crate::ln::channelmanager::ChannelManager::fail_htlc_backwards_with_reason
 374         PaymentClaimable {
 375                 /// The node that will receive the payment after it has been claimed.
 376                 /// This is useful to identify payments received via [phantom nodes].
 377                 /// This field will always be filled in when the event was generated by LDK versions
 378                 /// 0.0.113 and above.
 379                 ///
 380                 /// [phantom nodes]: crate::sign::PhantomKeysManager
 381                 receiver_node_id: Option<PublicKey>,
 382                 /// The hash for which the preimage should be handed to the ChannelManager. Note that LDK will
 383                 /// not stop you from registering duplicate payment hashes for inbound payments.
 384                 payment_hash: PaymentHash,
 385                 /// The fields in the onion which were received with each HTLC. Only fields which were
 386                 /// identical in each HTLC involved in the payment will be included here.
 387                 ///
 388                 /// Payments received on LDK versions prior to 0.0.115 will have this field unset.
 389                 onion_fields: Option<RecipientOnionFields>,
 390                 /// The value, in thousandths of a satoshi, that this payment is claimable for.
 391                 ///
 392                 /// May be less than the invoice amount if [`ChannelConfig::accept_underpaying_htlcs`] is set
 393                 /// and the previous hop took an extra fee.
 394                 ///
 395                 /// # Note
 396                 /// If [`ChannelConfig::accept_underpaying_htlcs`] is set and you claim without verifying this
 397                 /// field, you may lose money!
 398                 ///
 399                 /// [`ChannelConfig::accept_underpaying_htlcs`]: crate::util::config::ChannelConfig::accept_underpaying_htlcs
 400                 amount_msat: u64,
 401                 /// The value, in thousands of a satoshi, that was skimmed off of this payment as an extra fee
 402                 /// taken by our channel counterparty.
 403                 ///
 404                 /// Will always be 0 unless [`ChannelConfig::accept_underpaying_htlcs`] is set.
 405                 ///
 406                 /// [`ChannelConfig::accept_underpaying_htlcs`]: crate::util::config::ChannelConfig::accept_underpaying_htlcs
 407                 counterparty_skimmed_fee_msat: u64,
 408                 /// Information for claiming this received payment, based on whether the purpose of the
 409                 /// payment is to pay an invoice or to send a spontaneous payment.
 410                 purpose: PaymentPurpose,
 411                 /// The `channel_id` indicating over which channel we received the payment.
 412                 via_channel_id: Option<[u8; 32]>,
 413                 /// The `user_channel_id` indicating over which channel we received the payment.
 414                 via_user_channel_id: Option<u128>,
 415                 /// The block height at which this payment will be failed back and will no longer be
 416                 /// eligible for claiming.
 417                 ///
 418                 /// Prior to this height, a call to [`ChannelManager::claim_funds`] is guaranteed to
 419                 /// succeed, however you should wait for [`Event::PaymentClaimed`] to be sure.
 420                 ///
 421                 /// [`ChannelManager::claim_funds`]: crate::ln::channelmanager::ChannelManager::claim_funds
 422                 claim_deadline: Option<u32>,
 423         },
 424         /// Indicates a payment has been claimed and we've received money!
 425         ///
 426         /// This most likely occurs when [`ChannelManager::claim_funds`] has been called in response
 427         /// to an [`Event::PaymentClaimable`]. However, if we previously crashed during a
 428         /// [`ChannelManager::claim_funds`] call you may see this event without a corresponding
 429         /// [`Event::PaymentClaimable`] event.
 430         ///
 431         /// # Note
 432         /// LDK will not stop an inbound payment from being paid multiple times, so multiple
 433         /// `PaymentClaimable` events may be generated for the same payment. If you then call
 434         /// [`ChannelManager::claim_funds`] twice for the same [`Event::PaymentClaimable`] you may get
 435         /// multiple `PaymentClaimed` events.
 436         ///
 437         /// [`ChannelManager::claim_funds`]: crate::ln::channelmanager::ChannelManager::claim_funds
 438         PaymentClaimed {
 439                 /// The node that received the payment.
 440                 /// This is useful to identify payments which were received via [phantom nodes].
 441                 /// This field will always be filled in when the event was generated by LDK versions
 442                 /// 0.0.113 and above.
 443                 ///
 444                 /// [phantom nodes]: crate::sign::PhantomKeysManager
 445                 receiver_node_id: Option<PublicKey>,
 446                 /// The payment hash of the claimed payment. Note that LDK will not stop you from
 447                 /// registering duplicate payment hashes for inbound payments.
 448                 payment_hash: PaymentHash,
 449                 /// The value, in thousandths of a satoshi, that this payment is for.
 450                 amount_msat: u64,
 451                 /// The purpose of the claimed payment, i.e. whether the payment was for an invoice or a
 452                 /// spontaneous payment.
 453                 purpose: PaymentPurpose,
 454         },
 455         /// Indicates an outbound payment we made succeeded (i.e. it made it all the way to its target
 456         /// and we got back the payment preimage for it).
 457         ///
 458         /// Note for MPP payments: in rare cases, this event may be preceded by a `PaymentPathFailed`
 459         /// event. In this situation, you SHOULD treat this payment as having succeeded.
 460         PaymentSent {
 461                 /// The `payment_id` passed to [`ChannelManager::send_payment`].
 462                 ///
 463                 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
 464                 payment_id: Option<PaymentId>,
 465                 /// The preimage to the hash given to ChannelManager::send_payment.
 466                 /// Note that this serves as a payment receipt, if you wish to have such a thing, you must
 467                 /// store it somehow!
 468                 payment_preimage: PaymentPreimage,
 469                 /// The hash that was given to [`ChannelManager::send_payment`].
 470                 ///
 471                 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
 472                 payment_hash: PaymentHash,
 473                 /// The total fee which was spent at intermediate hops in this payment, across all paths.
 474                 ///
 475                 /// Note that, like [`Route::get_total_fees`] this does *not* include any potential
 476                 /// overpayment to the recipient node.
 477                 ///
 478                 /// If the recipient or an intermediate node misbehaves and gives us free money, this may
 479                 /// overstate the amount paid, though this is unlikely.
 480                 ///
 481                 /// [`Route::get_total_fees`]: crate::routing::router::Route::get_total_fees
 482                 fee_paid_msat: Option<u64>,
 483         },
 484         /// Indicates an outbound payment failed. Individual [`Event::PaymentPathFailed`] events
 485         /// provide failure information for each path attempt in the payment, including retries.
 486         ///
 487         /// This event is provided once there are no further pending HTLCs for the payment and the
 488         /// payment is no longer retryable, due either to the [`Retry`] provided or
 489         /// [`ChannelManager::abandon_payment`] having been called for the corresponding payment.
 490         ///
 491         /// [`Retry`]: crate::ln::channelmanager::Retry
 492         /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
 493         PaymentFailed {
 494                 /// The `payment_id` passed to [`ChannelManager::send_payment`].
 495                 ///
 496                 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
 497                 payment_id: PaymentId,
 498                 /// The hash that was given to [`ChannelManager::send_payment`].
 499                 ///
 500                 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
 501                 payment_hash: PaymentHash,
 502                 /// The reason the payment failed. This is only `None` for events generated or serialized
 503                 /// by versions prior to 0.0.115.
 504                 reason: Option<PaymentFailureReason>,
 505         },
 506         /// Indicates that a path for an outbound payment was successful.
 507         ///
 508         /// Always generated after [`Event::PaymentSent`] and thus useful for scoring channels. See
 509         /// [`Event::PaymentSent`] for obtaining the payment preimage.
 510         PaymentPathSuccessful {
 511                 /// The `payment_id` passed to [`ChannelManager::send_payment`].
 512                 ///
 513                 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
 514                 payment_id: PaymentId,
 515                 /// The hash that was given to [`ChannelManager::send_payment`].
 516                 ///
 517                 /// This will be `Some` for all payments which completed on LDK 0.0.104 or later.
 518                 ///
 519                 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
 520                 payment_hash: Option<PaymentHash>,
 521                 /// The payment path that was successful.
 522                 ///
 523                 /// May contain a closed channel if the HTLC sent along the path was fulfilled on chain.
 524                 path: Path,
 525         },
 526         /// Indicates an outbound HTLC we sent failed, likely due to an intermediary node being unable to
 527         /// handle the HTLC.
 528         ///
 529         /// Note that this does *not* indicate that all paths for an MPP payment have failed, see
 530         /// [`Event::PaymentFailed`].
 531         ///
 532         /// See [`ChannelManager::abandon_payment`] for giving up on this payment before its retries have
 533         /// been exhausted.
 534         ///
 535         /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
 536         PaymentPathFailed {
 537                 /// The `payment_id` passed to [`ChannelManager::send_payment`].
 538                 ///
 539                 /// This will be `Some` for all payment paths which failed on LDK 0.0.103 or later.
 540                 ///
 541                 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
 542                 /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
 543                 payment_id: Option<PaymentId>,
 544                 /// The hash that was given to [`ChannelManager::send_payment`].
 545                 ///
 546                 /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
 547                 payment_hash: PaymentHash,
 548                 /// Indicates the payment was rejected for some reason by the recipient. This implies that
 549                 /// the payment has failed, not just the route in question. If this is not set, the payment may
 550                 /// be retried via a different route.
 551                 payment_failed_permanently: bool,
 552                 /// Extra error details based on the failure type. May contain an update that needs to be
 553                 /// applied to the [`NetworkGraph`].
 554                 ///
 555                 /// [`NetworkGraph`]: crate::routing::gossip::NetworkGraph
 556                 failure: PathFailure,
 557                 /// The payment path that failed.
 558                 path: Path,
 559                 /// The channel responsible for the failed payment path.
 560                 ///
 561                 /// Note that for route hints or for the first hop in a path this may be an SCID alias and
 562                 /// may not refer to a channel in the public network graph. These aliases may also collide
 563                 /// with channels in the public network graph.
 564                 ///
 565                 /// If this is `Some`, then the corresponding channel should be avoided when the payment is
 566                 /// retried. May be `None` for older [`Event`] serializations.
 567                 short_channel_id: Option<u64>,
 568 #[cfg(test)]
 569                 error_code: Option<u16>,
 570 #[cfg(test)]
 571                 error_data: Option<Vec<u8>>,
 572         },
 573         /// Indicates that a probe payment we sent returned successful, i.e., only failed at the destination.
 574         ProbeSuccessful {
 575                 /// The id returned by [`ChannelManager::send_probe`].
 576                 ///
 577                 /// [`ChannelManager::send_probe`]: crate::ln::channelmanager::ChannelManager::send_probe
 578                 payment_id: PaymentId,
 579                 /// The hash generated by [`ChannelManager::send_probe`].
 580                 ///
 581                 /// [`ChannelManager::send_probe`]: crate::ln::channelmanager::ChannelManager::send_probe
 582                 payment_hash: PaymentHash,
 583                 /// The payment path that was successful.
 584                 path: Path,
 585         },
 586         /// Indicates that a probe payment we sent failed at an intermediary node on the path.
 587         ProbeFailed {
 588                 /// The id returned by [`ChannelManager::send_probe`].
 589                 ///
 590                 /// [`ChannelManager::send_probe`]: crate::ln::channelmanager::ChannelManager::send_probe
 591                 payment_id: PaymentId,
 592                 /// The hash generated by [`ChannelManager::send_probe`].
 593                 ///
 594                 /// [`ChannelManager::send_probe`]: crate::ln::channelmanager::ChannelManager::send_probe
 595                 payment_hash: PaymentHash,
 596                 /// The payment path that failed.
 597                 path: Path,
 598                 /// The channel responsible for the failed probe.
 599                 ///
 600                 /// Note that for route hints or for the first hop in a path this may be an SCID alias and
 601                 /// may not refer to a channel in the public network graph. These aliases may also collide
 602                 /// with channels in the public network graph.
 603                 short_channel_id: Option<u64>,
 604         },
 605         /// Used to indicate that [`ChannelManager::process_pending_htlc_forwards`] should be called at
 606         /// a time in the future.
 607         ///
 608         /// [`ChannelManager::process_pending_htlc_forwards`]: crate::ln::channelmanager::ChannelManager::process_pending_htlc_forwards
 609         PendingHTLCsForwardable {
 610                 /// The minimum amount of time that should be waited prior to calling
 611                 /// process_pending_htlc_forwards. To increase the effort required to correlate payments,
 612                 /// you should wait a random amount of time in roughly the range (now + time_forwardable,
 613                 /// now + 5*time_forwardable).
 614                 time_forwardable: Duration,
 615         },
 616         /// Used to indicate that we've intercepted an HTLC forward. This event will only be generated if
 617         /// you've encoded an intercept scid in the receiver's invoice route hints using
 618         /// [`ChannelManager::get_intercept_scid`] and have set [`UserConfig::accept_intercept_htlcs`].
 619         ///
 620         /// [`ChannelManager::forward_intercepted_htlc`] or
 621         /// [`ChannelManager::fail_intercepted_htlc`] MUST be called in response to this event. See
 622         /// their docs for more information.
 623         ///
 624         /// [`ChannelManager::get_intercept_scid`]: crate::ln::channelmanager::ChannelManager::get_intercept_scid
 625         /// [`UserConfig::accept_intercept_htlcs`]: crate::util::config::UserConfig::accept_intercept_htlcs
 626         /// [`ChannelManager::forward_intercepted_htlc`]: crate::ln::channelmanager::ChannelManager::forward_intercepted_htlc
 627         /// [`ChannelManager::fail_intercepted_htlc`]: crate::ln::channelmanager::ChannelManager::fail_intercepted_htlc
 628         HTLCIntercepted {
 629                 /// An id to help LDK identify which HTLC is being forwarded or failed.
 630                 intercept_id: InterceptId,
 631                 /// The fake scid that was programmed as the next hop's scid, generated using
 632                 /// [`ChannelManager::get_intercept_scid`].
 633                 ///
 634                 /// [`ChannelManager::get_intercept_scid`]: crate::ln::channelmanager::ChannelManager::get_intercept_scid
 635                 requested_next_hop_scid: u64,
 636                 /// The payment hash used for this HTLC.
 637                 payment_hash: PaymentHash,
 638                 /// How many msats were received on the inbound edge of this HTLC.
 639                 inbound_amount_msat: u64,
 640                 /// How many msats the payer intended to route to the next node. Depending on the reason you are
 641                 /// intercepting this payment, you might take a fee by forwarding less than this amount.
 642                 /// Forwarding less than this amount may break compatibility with LDK versions prior to 0.0.116.
 643                 ///
 644                 /// Note that LDK will NOT check that expected fees were factored into this value. You MUST
 645                 /// check that whatever fee you want has been included here or subtract it as required. Further,
 646                 /// LDK will not stop you from forwarding more than you received.
 647                 expected_outbound_amount_msat: u64,
 648         },
 649         /// Used to indicate that an output which you should know how to spend was confirmed on chain
 650         /// and is now spendable.
 651         /// Such an output will *not* ever be spent by rust-lightning, and are not at risk of your
 652         /// counterparty spending them due to some kind of timeout. Thus, you need to store them
 653         /// somewhere and spend them when you create on-chain transactions.
 654         SpendableOutputs {
 655                 /// The outputs which you should store as spendable by you.
 656                 outputs: Vec<SpendableOutputDescriptor>,
 657         },
 658         /// This event is generated when a payment has been successfully forwarded through us and a
 659         /// forwarding fee earned.
 660         PaymentForwarded {
 661                 /// The incoming channel between the previous node and us. This is only `None` for events
 662                 /// generated or serialized by versions prior to 0.0.107.
 663                 prev_channel_id: Option<[u8; 32]>,
 664                 /// The outgoing channel between the next node and us. This is only `None` for events
 665                 /// generated or serialized by versions prior to 0.0.107.
 666                 next_channel_id: Option<[u8; 32]>,
 667                 /// The fee, in milli-satoshis, which was earned as a result of the payment.
 668                 ///
 669                 /// Note that if we force-closed the channel over which we forwarded an HTLC while the HTLC
 670                 /// was pending, the amount the next hop claimed will have been rounded down to the nearest
 671                 /// whole satoshi. Thus, the fee calculated here may be higher than expected as we still
 672                 /// claimed the full value in millisatoshis from the source. In this case,
 673                 /// `claim_from_onchain_tx` will be set.
 674                 ///
 675                 /// If the channel which sent us the payment has been force-closed, we will claim the funds
 676                 /// via an on-chain transaction. In that case we do not yet know the on-chain transaction
 677                 /// fees which we will spend and will instead set this to `None`. It is possible duplicate
 678                 /// `PaymentForwarded` events are generated for the same payment iff `fee_earned_msat` is
 679                 /// `None`.
 680                 fee_earned_msat: Option<u64>,
 681                 /// If this is `true`, the forwarded HTLC was claimed by our counterparty via an on-chain
 682                 /// transaction.
 683                 claim_from_onchain_tx: bool,
 684                 /// The final amount forwarded, in milli-satoshis, after the fee is deducted.
 685                 ///
 686                 /// The caveat described above the `fee_earned_msat` field applies here as well.
 687                 outbound_amount_forwarded_msat: Option<u64>,
 688         },
 689         /// Used to indicate that a channel with the given `channel_id` is being opened and pending
 690         /// confirmation on-chain.
 691         ///
 692         /// This event is emitted when the funding transaction has been signed and is broadcast to the
 693         /// network. For 0conf channels it will be immediately followed by the corresponding
 694         /// [`Event::ChannelReady`] event.
 695         ChannelPending {
 696                 /// The `channel_id` of the channel that is pending confirmation.
 697                 channel_id: [u8; 32],
 698                 /// The `user_channel_id` value passed in to [`ChannelManager::create_channel`] for outbound
 699                 /// channels, or to [`ChannelManager::accept_inbound_channel`] for inbound channels if
 700                 /// [`UserConfig::manually_accept_inbound_channels`] config flag is set to true. Otherwise
 701                 /// `user_channel_id` will be randomized for an inbound channel.
 702                 ///
 703                 /// [`ChannelManager::create_channel`]: crate::ln::channelmanager::ChannelManager::create_channel
 704                 /// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
 705                 /// [`UserConfig::manually_accept_inbound_channels`]: crate::util::config::UserConfig::manually_accept_inbound_channels
 706                 user_channel_id: u128,
 707                 /// The `temporary_channel_id` this channel used to be known by during channel establishment.
 708                 ///
 709                 /// Will be `None` for channels created prior to LDK version 0.0.115.
 710                 former_temporary_channel_id: Option<[u8; 32]>,
 711                 /// The `node_id` of the channel counterparty.
 712                 counterparty_node_id: PublicKey,
 713                 /// The outpoint of the channel's funding transaction.
 714                 funding_txo: OutPoint,
 715         },
 716         /// Used to indicate that a channel with the given `channel_id` is ready to
 717         /// be used. This event is emitted either when the funding transaction has been confirmed
 718         /// on-chain, or, in case of a 0conf channel, when both parties have confirmed the channel
 719         /// establishment.
 720         ChannelReady {
 721                 /// The `channel_id` of the channel that is ready.
 722                 channel_id: [u8; 32],
 723                 /// The `user_channel_id` value passed in to [`ChannelManager::create_channel`] for outbound
 724                 /// channels, or to [`ChannelManager::accept_inbound_channel`] for inbound channels if
 725                 /// [`UserConfig::manually_accept_inbound_channels`] config flag is set to true. Otherwise
 726                 /// `user_channel_id` will be randomized for an inbound channel.
 727                 ///
 728                 /// [`ChannelManager::create_channel`]: crate::ln::channelmanager::ChannelManager::create_channel
 729                 /// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
 730                 /// [`UserConfig::manually_accept_inbound_channels`]: crate::util::config::UserConfig::manually_accept_inbound_channels
 731                 user_channel_id: u128,
 732                 /// The `node_id` of the channel counterparty.
 733                 counterparty_node_id: PublicKey,
 734                 /// The features that this channel will operate with.
 735                 channel_type: ChannelTypeFeatures,
 736         },
 737         /// Used to indicate that a previously opened channel with the given `channel_id` is in the
 738         /// process of closure.
 739         ChannelClosed  {
 740                 /// The `channel_id` of the channel which has been closed. Note that on-chain transactions
 741                 /// resolving the channel are likely still awaiting confirmation.
 742                 channel_id: [u8; 32],
 743                 /// The `user_channel_id` value passed in to [`ChannelManager::create_channel`] for outbound
 744                 /// channels, or to [`ChannelManager::accept_inbound_channel`] for inbound channels if
 745                 /// [`UserConfig::manually_accept_inbound_channels`] config flag is set to true. Otherwise
 746                 /// `user_channel_id` will be randomized for inbound channels.
 747                 /// This may be zero for inbound channels serialized prior to 0.0.113 and will always be
 748                 /// zero for objects serialized with LDK versions prior to 0.0.102.
 749                 ///
 750                 /// [`ChannelManager::create_channel`]: crate::ln::channelmanager::ChannelManager::create_channel
 751                 /// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
 752                 /// [`UserConfig::manually_accept_inbound_channels`]: crate::util::config::UserConfig::manually_accept_inbound_channels
 753                 user_channel_id: u128,
 754                 /// The reason the channel was closed.
 755                 reason: ClosureReason
 756         },
 757         /// Used to indicate to the user that they can abandon the funding transaction and recycle the
 758         /// inputs for another purpose.
 759         DiscardFunding {
 760                 /// The channel_id of the channel which has been closed.
 761                 channel_id: [u8; 32],
 762                 /// The full transaction received from the user
 763                 transaction: Transaction
 764         },
 765         /// Indicates a request to open a new channel by a peer.
 766         ///
 767         /// To accept the request, call [`ChannelManager::accept_inbound_channel`]. To reject the
 768         /// request, call [`ChannelManager::force_close_without_broadcasting_txn`].
 769         ///
 770         /// The event is only triggered when a new open channel request is received and the
 771         /// [`UserConfig::manually_accept_inbound_channels`] config flag is set to true.
 772         ///
 773         /// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
 774         /// [`ChannelManager::force_close_without_broadcasting_txn`]: crate::ln::channelmanager::ChannelManager::force_close_without_broadcasting_txn
 775         /// [`UserConfig::manually_accept_inbound_channels`]: crate::util::config::UserConfig::manually_accept_inbound_channels
 776         OpenChannelRequest {
 777                 /// The temporary channel ID of the channel requested to be opened.
 778                 ///
 779                 /// When responding to the request, the `temporary_channel_id` should be passed
 780                 /// back to the ChannelManager through [`ChannelManager::accept_inbound_channel`] to accept,
 781                 /// or through [`ChannelManager::force_close_without_broadcasting_txn`] to reject.
 782                 ///
 783                 /// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
 784                 /// [`ChannelManager::force_close_without_broadcasting_txn`]: crate::ln::channelmanager::ChannelManager::force_close_without_broadcasting_txn
 785                 temporary_channel_id: [u8; 32],
 786                 /// The node_id of the counterparty requesting to open the channel.
 787                 ///
 788                 /// When responding to the request, the `counterparty_node_id` should be passed
 789                 /// back to the `ChannelManager` through [`ChannelManager::accept_inbound_channel`] to
 790                 /// accept the request, or through [`ChannelManager::force_close_without_broadcasting_txn`] to reject the
 791                 /// request.
 792                 ///
 793                 /// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
 794                 /// [`ChannelManager::force_close_without_broadcasting_txn`]: crate::ln::channelmanager::ChannelManager::force_close_without_broadcasting_txn
 795                 counterparty_node_id: PublicKey,
 796                 /// The channel value of the requested channel.
 797                 funding_satoshis: u64,
 798                 /// Our starting balance in the channel if the request is accepted, in milli-satoshi.
 799                 push_msat: u64,
 800                 /// The features that this channel will operate with. If you reject the channel, a
 801                 /// well-behaved counterparty may automatically re-attempt the channel with a new set of
 802                 /// feature flags.
 803                 ///
 804                 /// Note that if [`ChannelTypeFeatures::supports_scid_privacy`] returns true on this type,
 805                 /// the resulting [`ChannelManager`] will not be readable by versions of LDK prior to
 806                 /// 0.0.106.
 807                 ///
 808                 /// Furthermore, note that if [`ChannelTypeFeatures::supports_zero_conf`] returns true on this type,
 809                 /// the resulting [`ChannelManager`] will not be readable by versions of LDK prior to
 810                 /// 0.0.107. Channels setting this type also need to get manually accepted via
 811                 /// [`crate::ln::channelmanager::ChannelManager::accept_inbound_channel_from_trusted_peer_0conf`],
 812                 /// or will be rejected otherwise.
 813                 ///
 814                 /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
 815                 channel_type: ChannelTypeFeatures,
 816         },
 817         /// Indicates that the HTLC was accepted, but could not be processed when or after attempting to
 818         /// forward it.
 819         ///
 820         /// Some scenarios where this event may be sent include:
 821         /// * Insufficient capacity in the outbound channel
 822         /// * While waiting to forward the HTLC, the channel it is meant to be forwarded through closes
 823         /// * When an unknown SCID is requested for forwarding a payment.
 824         /// * Expected MPP amount has already been reached
 825         /// * The HTLC has timed out
 826         ///
 827         /// This event, however, does not get generated if an HTLC fails to meet the forwarding
 828         /// requirements (i.e. insufficient fees paid, or a CLTV that is too soon).
 829         HTLCHandlingFailed {
 830                 /// The channel over which the HTLC was received.
 831                 prev_channel_id: [u8; 32],
 832                 /// Destination of the HTLC that failed to be processed.
 833                 failed_next_destination: HTLCDestination,
 834         },
 835         #[cfg(anchors)]
 836         /// Indicates that a transaction originating from LDK needs to have its fee bumped. This event
 837         /// requires confirmed external funds to be readily available to spend.
 838         ///
 839         /// LDK does not currently generate this event. It is limited to the scope of channels with
 840         /// anchor outputs, which will be introduced in a future release.
 841         BumpTransaction(BumpTransactionEvent),
 842 }
 843
 844 impl Writeable for Event {
 845         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 846                 match self {
 847                         &Event::FundingGenerationReady { .. } => {
 848                                 0u8.write(writer)?;
 849                                 // We never write out FundingGenerationReady events as, upon disconnection, peers
 850                                 // drop any channels which have not yet exchanged funding_signed.
 851                         },
 852                         &Event::PaymentClaimable { ref payment_hash, ref amount_msat, counterparty_skimmed_fee_msat,
 853                                 ref purpose, ref receiver_node_id, ref via_channel_id, ref via_user_channel_id,
 854                                 ref claim_deadline, ref onion_fields
 855                         } => {
 856                                 1u8.write(writer)?;
 857                                 let mut payment_secret = None;
 858                                 let payment_preimage;
 859                                 match &purpose {
 860                                         PaymentPurpose::InvoicePayment { payment_preimage: preimage, payment_secret: secret } => {
 861                                                 payment_secret = Some(secret);
 862                                                 payment_preimage = *preimage;
 863                                         },
 864                                         PaymentPurpose::SpontaneousPayment(preimage) => {
 865                                                 payment_preimage = Some(*preimage);
 866                                         }
 867                                 }
 868                                 let skimmed_fee_opt = if counterparty_skimmed_fee_msat == 0 { None }
 869                                         else { Some(counterparty_skimmed_fee_msat) };
 870                                 write_tlv_fields!(writer, {
 871                                         (0, payment_hash, required),
 872                                         (1, receiver_node_id, option),
 873                                         (2, payment_secret, option),
 874                                         (3, via_channel_id, option),
 875                                         (4, amount_msat, required),
 876                                         (5, via_user_channel_id, option),
 877                                         (6, 0u64, required), // user_payment_id required for compatibility with 0.0.103 and earlier
 878                                         (7, claim_deadline, option),
 879                                         (8, payment_preimage, option),
 880                                         (9, onion_fields, option),
 881                                         (10, skimmed_fee_opt, option),
 882                                 });
 883                         },
 884                         &Event::PaymentSent { ref payment_id, ref payment_preimage, ref payment_hash, ref fee_paid_msat } => {
 885                                 2u8.write(writer)?;
 886                                 write_tlv_fields!(writer, {
 887                                         (0, payment_preimage, required),
 888                                         (1, payment_hash, required),
 889                                         (3, payment_id, option),
 890                                         (5, fee_paid_msat, option),
 891                                 });
 892                         },
 893                         &Event::PaymentPathFailed {
 894                                 ref payment_id, ref payment_hash, ref payment_failed_permanently, ref failure,
 895                                 ref path, ref short_channel_id,
 896                                 #[cfg(test)]
 897                                 ref error_code,
 898                                 #[cfg(test)]
 899                                 ref error_data,
 900                         } => {
 901                                 3u8.write(writer)?;
 902                                 #[cfg(test)]
 903                                 error_code.write(writer)?;
 904                                 #[cfg(test)]
 905                                 error_data.write(writer)?;
 906                                 write_tlv_fields!(writer, {
 907                                         (0, payment_hash, required),
 908                                         (1, None::<NetworkUpdate>, option), // network_update in LDK versions prior to 0.0.114
 909                                         (2, payment_failed_permanently, required),
 910                                         (3, false, required), // all_paths_failed in LDK versions prior to 0.0.114
 911                                         (4, path.blinded_tail, option),
 912                                         (5, path.hops, vec_type),
 913                                         (7, short_channel_id, option),
 914                                         (9, None::<RouteParameters>, option), // retry in LDK versions prior to 0.0.115
 915                                         (11, payment_id, option),
 916                                         (13, failure, required),
 917                                 });
 918                         },
 919                         &Event::PendingHTLCsForwardable { time_forwardable: _ } => {
 920                                 4u8.write(writer)?;
 921                                 // Note that we now ignore these on the read end as we'll re-generate them in
 922                                 // ChannelManager, we write them here only for backwards compatibility.
 923                         },
 924                         &Event::SpendableOutputs { ref outputs } => {
 925                                 5u8.write(writer)?;
 926                                 write_tlv_fields!(writer, {
 927                                         (0, WithoutLength(outputs), required),
 928                                 });
 929                         },
 930                         &Event::HTLCIntercepted { requested_next_hop_scid, payment_hash, inbound_amount_msat, expected_outbound_amount_msat, intercept_id } => {
 931                                 6u8.write(writer)?;
 932                                 let intercept_scid = InterceptNextHop::FakeScid { requested_next_hop_scid };
 933                                 write_tlv_fields!(writer, {
 934                                         (0, intercept_id, required),
 935                                         (2, intercept_scid, required),
 936                                         (4, payment_hash, required),
 937                                         (6, inbound_amount_msat, required),
 938                                         (8, expected_outbound_amount_msat, required),
 939                                 });
 940                         }
 941                         &Event::PaymentForwarded {
 942                                 fee_earned_msat, prev_channel_id, claim_from_onchain_tx,
 943                                 next_channel_id, outbound_amount_forwarded_msat
 944                         } => {
 945                                 7u8.write(writer)?;
 946                                 write_tlv_fields!(writer, {
 947                                         (0, fee_earned_msat, option),
 948                                         (1, prev_channel_id, option),
 949                                         (2, claim_from_onchain_tx, required),
 950                                         (3, next_channel_id, option),
 951                                         (5, outbound_amount_forwarded_msat, option),
 952                                 });
 953                         },
 954                         &Event::ChannelClosed { ref channel_id, ref user_channel_id, ref reason } => {
 955                                 9u8.write(writer)?;
 956                                 // `user_channel_id` used to be a single u64 value. In order to remain backwards
 957                                 // compatible with versions prior to 0.0.113, the u128 is serialized as two
 958                                 // separate u64 values.
 959                                 let user_channel_id_low = *user_channel_id as u64;
 960                                 let user_channel_id_high = (*user_channel_id >> 64) as u64;
 961                                 write_tlv_fields!(writer, {
 962                                         (0, channel_id, required),
 963                                         (1, user_channel_id_low, required),
 964                                         (2, reason, required),
 965                                         (3, user_channel_id_high, required),
 966                                 });
 967                         },
 968                         &Event::DiscardFunding { ref channel_id, ref transaction } => {
 969                                 11u8.write(writer)?;
 970                                 write_tlv_fields!(writer, {
 971                                         (0, channel_id, required),
 972                                         (2, transaction, required)
 973                                 })
 974                         },
 975                         &Event::PaymentPathSuccessful { ref payment_id, ref payment_hash, ref path } => {
 976                                 13u8.write(writer)?;
 977                                 write_tlv_fields!(writer, {
 978                                         (0, payment_id, required),
 979                                         (2, payment_hash, option),
 980                                         (4, path.hops, vec_type),
 981                                         (6, path.blinded_tail, option),
 982                                 })
 983                         },
 984                         &Event::PaymentFailed { ref payment_id, ref payment_hash, ref reason } => {
 985                                 15u8.write(writer)?;
 986                                 write_tlv_fields!(writer, {
 987                                         (0, payment_id, required),
 988                                         (1, reason, option),
 989                                         (2, payment_hash, required),
 990                                 })
 991                         },
 992                         &Event::OpenChannelRequest { .. } => {
 993                                 17u8.write(writer)?;
 994                                 // We never write the OpenChannelRequest events as, upon disconnection, peers
 995                                 // drop any channels which have not yet exchanged funding_signed.
 996                         },
 997                         &Event::PaymentClaimed { ref payment_hash, ref amount_msat, ref purpose, ref receiver_node_id } => {
 998                                 19u8.write(writer)?;
 999                                 write_tlv_fields!(writer, {
1000                                         (0, payment_hash, required),
1001                                         (1, receiver_node_id, option),
1002                                         (2, purpose, required),
1003                                         (4, amount_msat, required),
1004                                 });
1005                         },
1006                         &Event::ProbeSuccessful { ref payment_id, ref payment_hash, ref path } => {
1007                                 21u8.write(writer)?;
1008                                 write_tlv_fields!(writer, {
1009                                         (0, payment_id, required),
1010                                         (2, payment_hash, required),
1011                                         (4, path.hops, vec_type),
1012                                         (6, path.blinded_tail, option),
1013                                 })
1014                         },
1015                         &Event::ProbeFailed { ref payment_id, ref payment_hash, ref path, ref short_channel_id } => {
1016                                 23u8.write(writer)?;
1017                                 write_tlv_fields!(writer, {
1018                                         (0, payment_id, required),
1019                                         (2, payment_hash, required),
1020                                         (4, path.hops, vec_type),
1021                                         (6, short_channel_id, option),
1022                                         (8, path.blinded_tail, option),
1023                                 })
1024                         },
1025                         &Event::HTLCHandlingFailed { ref prev_channel_id, ref failed_next_destination } => {
1026                                 25u8.write(writer)?;
1027                                 write_tlv_fields!(writer, {
1028                                         (0, prev_channel_id, required),
1029                                         (2, failed_next_destination, required),
1030                                 })
1031                         },
1032                         #[cfg(anchors)]
1033                         &Event::BumpTransaction(ref event)=> {
1034                                 27u8.write(writer)?;
1035                                 match event {
1036                                         // We never write the ChannelClose|HTLCResolution events as they'll be replayed
1037                                         // upon restarting anyway if they remain unresolved.
1038                                         BumpTransactionEvent::ChannelClose { .. } => {}
1039                                         BumpTransactionEvent::HTLCResolution { .. } => {}
1040                                 }
1041                                 write_tlv_fields!(writer, {}); // Write a length field for forwards compat
1042                         }
1043                         &Event::ChannelReady { ref channel_id, ref user_channel_id, ref counterparty_node_id, ref channel_type } => {
1044                                 29u8.write(writer)?;
1045                                 write_tlv_fields!(writer, {
1046                                         (0, channel_id, required),
1047                                         (2, user_channel_id, required),
1048                                         (4, counterparty_node_id, required),
1049                                         (6, channel_type, required),
1050                                 });
1051                         },
1052                         &Event::ChannelPending { ref channel_id, ref user_channel_id, ref former_temporary_channel_id, ref counterparty_node_id, ref funding_txo } => {
1053                                 31u8.write(writer)?;
1054                                 write_tlv_fields!(writer, {
1055                                         (0, channel_id, required),
1056                                         (2, user_channel_id, required),
1057                                         (4, former_temporary_channel_id, required),
1058                                         (6, counterparty_node_id, required),
1059                                         (8, funding_txo, required),
1060                                 });
1061                         },
1062                         // Note that, going forward, all new events must only write data inside of
1063                         // `write_tlv_fields`. Versions 0.0.101+ will ignore odd-numbered events that write
1064                         // data via `write_tlv_fields`.
1065                 }
1066                 Ok(())
1067         }
1068 }
1069 impl MaybeReadable for Event {
1070         fn read<R: io::Read>(reader: &mut R) -> Result<Option<Self>, msgs::DecodeError> {
1071                 match Readable::read(reader)? {
1072                         // Note that we do not write a length-prefixed TLV for FundingGenerationReady events,
1073                         // unlike all other events, thus we return immediately here.
1074                         0u8 => Ok(None),
1075                         1u8 => {
1076                                 let f = || {
1077                                         let mut payment_hash = PaymentHash([0; 32]);
1078                                         let mut payment_preimage = None;
1079                                         let mut payment_secret = None;
1080                                         let mut amount_msat = 0;
1081                                         let mut counterparty_skimmed_fee_msat_opt = None;
1082                                         let mut receiver_node_id = None;
1083                                         let mut _user_payment_id = None::<u64>; // For compatibility with 0.0.103 and earlier
1084                                         let mut via_channel_id = None;
1085                                         let mut claim_deadline = None;
1086                                         let mut via_user_channel_id = None;
1087                                         let mut onion_fields = None;
1088                                         read_tlv_fields!(reader, {
1089                                                 (0, payment_hash, required),
1090                                                 (1, receiver_node_id, option),
1091                                                 (2, payment_secret, option),
1092                                                 (3, via_channel_id, option),
1093                                                 (4, amount_msat, required),
1094                                                 (5, via_user_channel_id, option),
1095                                                 (6, _user_payment_id, option),
1096                                                 (7, claim_deadline, option),
1097                                                 (8, payment_preimage, option),
1098                                                 (9, onion_fields, option),
1099                                                 (10, counterparty_skimmed_fee_msat_opt, option),
1100                                         });
1101                                         let purpose = match payment_secret {
1102                                                 Some(secret) => PaymentPurpose::InvoicePayment {
1103                                                         payment_preimage,
1104                                                         payment_secret: secret
1105                                                 },
1106                                                 None if payment_preimage.is_some() => PaymentPurpose::SpontaneousPayment(payment_preimage.unwrap()),
1107                                                 None => return Err(msgs::DecodeError::InvalidValue),
1108                                         };
1109                                         Ok(Some(Event::PaymentClaimable {
1110                                                 receiver_node_id,
1111                                                 payment_hash,
1112                                                 amount_msat,
1113                                                 counterparty_skimmed_fee_msat: counterparty_skimmed_fee_msat_opt.unwrap_or(0),
1114                                                 purpose,
1115                                                 via_channel_id,
1116                                                 via_user_channel_id,
1117                                                 claim_deadline,
1118                                                 onion_fields,
1119                                         }))
1120                                 };
1121                                 f()
1122                         },
1123                         2u8 => {
1124                                 let f = || {
1125                                         let mut payment_preimage = PaymentPreimage([0; 32]);
1126                                         let mut payment_hash = None;
1127                                         let mut payment_id = None;
1128                                         let mut fee_paid_msat = None;
1129                                         read_tlv_fields!(reader, {
1130                                                 (0, payment_preimage, required),
1131                                                 (1, payment_hash, option),
1132                                                 (3, payment_id, option),
1133                                                 (5, fee_paid_msat, option),
1134                                         });
1135                                         if payment_hash.is_none() {
1136                                                 payment_hash = Some(PaymentHash(Sha256::hash(&payment_preimage.0[..]).into_inner()));
1137                                         }
1138                                         Ok(Some(Event::PaymentSent {
1139                                                 payment_id,
1140                                                 payment_preimage,
1141                                                 payment_hash: payment_hash.unwrap(),
1142                                                 fee_paid_msat,
1143                                         }))
1144                                 };
1145                                 f()
1146                         },
1147                         3u8 => {
1148                                 let f = || {
1149                                         #[cfg(test)]
1150                                         let error_code = Readable::read(reader)?;
1151                                         #[cfg(test)]
1152                                         let error_data = Readable::read(reader)?;
1153                                         let mut payment_hash = PaymentHash([0; 32]);
1154                                         let mut payment_failed_permanently = false;
1155                                         let mut network_update = None;
1156                                         let mut blinded_tail: Option<BlindedTail> = None;
1157                                         let mut path: Option<Vec<RouteHop>> = Some(vec![]);
1158                                         let mut short_channel_id = None;
1159                                         let mut payment_id = None;
1160                                         let mut failure_opt = None;
1161                                         read_tlv_fields!(reader, {
1162                                                 (0, payment_hash, required),
1163                                                 (1, network_update, upgradable_option),
1164                                                 (2, payment_failed_permanently, required),
1165                                                 (4, blinded_tail, option),
1166                                                 (5, path, vec_type),
1167                                                 (7, short_channel_id, option),
1168                                                 (11, payment_id, option),
1169                                                 (13, failure_opt, upgradable_option),
1170                                         });
1171                                         let failure = failure_opt.unwrap_or_else(|| PathFailure::OnPath { network_update });
1172                                         Ok(Some(Event::PaymentPathFailed {
1173                                                 payment_id,
1174                                                 payment_hash,
1175                                                 payment_failed_permanently,
1176                                                 failure,
1177                                                 path: Path { hops: path.unwrap(), blinded_tail },
1178                                                 short_channel_id,
1179                                                 #[cfg(test)]
1180                                                 error_code,
1181                                                 #[cfg(test)]
1182                                                 error_data,
1183                                         }))
1184                                 };
1185                                 f()
1186                         },
1187                         4u8 => Ok(None),
1188                         5u8 => {
1189                                 let f = || {
1190                                         let mut outputs = WithoutLength(Vec::new());
1191                                         read_tlv_fields!(reader, {
1192                                                 (0, outputs, required),
1193                                         });
1194                                         Ok(Some(Event::SpendableOutputs { outputs: outputs.0 }))
1195                                 };
1196                                 f()
1197                         },
1198                         6u8 => {
1199                                 let mut payment_hash = PaymentHash([0; 32]);
1200                                 let mut intercept_id = InterceptId([0; 32]);
1201                                 let mut requested_next_hop_scid = InterceptNextHop::FakeScid { requested_next_hop_scid: 0 };
1202                                 let mut inbound_amount_msat = 0;
1203                                 let mut expected_outbound_amount_msat = 0;
1204                                 read_tlv_fields!(reader, {
1205                                         (0, intercept_id, required),
1206                                         (2, requested_next_hop_scid, required),
1207                                         (4, payment_hash, required),
1208                                         (6, inbound_amount_msat, required),
1209                                         (8, expected_outbound_amount_msat, required),
1210                                 });
1211                                 let next_scid = match requested_next_hop_scid {
1212                                         InterceptNextHop::FakeScid { requested_next_hop_scid: scid } => scid
1213                                 };
1214                                 Ok(Some(Event::HTLCIntercepted {
1215                                         payment_hash,
1216                                         requested_next_hop_scid: next_scid,
1217                                         inbound_amount_msat,
1218                                         expected_outbound_amount_msat,
1219                                         intercept_id,
1220                                 }))
1221                         },
1222                         7u8 => {
1223                                 let f = || {
1224                                         let mut fee_earned_msat = None;
1225                                         let mut prev_channel_id = None;
1226                                         let mut claim_from_onchain_tx = false;
1227                                         let mut next_channel_id = None;
1228                                         let mut outbound_amount_forwarded_msat = None;
1229                                         read_tlv_fields!(reader, {
1230                                                 (0, fee_earned_msat, option),
1231                                                 (1, prev_channel_id, option),
1232                                                 (2, claim_from_onchain_tx, required),
1233                                                 (3, next_channel_id, option),
1234                                                 (5, outbound_amount_forwarded_msat, option),
1235                                         });
1236                                         Ok(Some(Event::PaymentForwarded {
1237                                                 fee_earned_msat, prev_channel_id, claim_from_onchain_tx, next_channel_id,
1238                                                 outbound_amount_forwarded_msat
1239                                         }))
1240                                 };
1241                                 f()
1242                         },
1243                         9u8 => {
1244                                 let f = || {
1245                                         let mut channel_id = [0; 32];
1246                                         let mut reason = UpgradableRequired(None);
1247                                         let mut user_channel_id_low_opt: Option<u64> = None;
1248                                         let mut user_channel_id_high_opt: Option<u64> = None;
1249                                         read_tlv_fields!(reader, {
1250                                                 (0, channel_id, required),
1251                                                 (1, user_channel_id_low_opt, option),
1252                                                 (2, reason, upgradable_required),
1253                                                 (3, user_channel_id_high_opt, option),
1254                                         });
1255
1256                                         // `user_channel_id` used to be a single u64 value. In order to remain
1257                                         // backwards compatible with versions prior to 0.0.113, the u128 is serialized
1258                                         // as two separate u64 values.
1259                                         let user_channel_id = (user_channel_id_low_opt.unwrap_or(0) as u128) +
1260                                                 ((user_channel_id_high_opt.unwrap_or(0) as u128) << 64);
1261
1262                                         Ok(Some(Event::ChannelClosed { channel_id, user_channel_id, reason: _init_tlv_based_struct_field!(reason, upgradable_required) }))
1263                                 };
1264                                 f()
1265                         },
1266                         11u8 => {
1267                                 let f = || {
1268                                         let mut channel_id = [0; 32];
1269                                         let mut transaction = Transaction{ version: 2, lock_time: PackedLockTime::ZERO, input: Vec::new(), output: Vec::new() };
1270                                         read_tlv_fields!(reader, {
1271                                                 (0, channel_id, required),
1272                                                 (2, transaction, required),
1273                                         });
1274                                         Ok(Some(Event::DiscardFunding { channel_id, transaction } ))
1275                                 };
1276                                 f()
1277                         },
1278                         13u8 => {
1279                                 let f = || {
1280                                         _init_and_read_tlv_fields!(reader, {
1281                                                 (0, payment_id, required),
1282                                                 (2, payment_hash, option),
1283                                                 (4, path, vec_type),
1284                                                 (6, blinded_tail, option),
1285                                         });
1286                                         Ok(Some(Event::PaymentPathSuccessful {
1287                                                 payment_id: payment_id.0.unwrap(),
1288                                                 payment_hash,
1289                                                 path: Path { hops: path.unwrap(), blinded_tail },
1290                                         }))
1291                                 };
1292                                 f()
1293                         },
1294                         15u8 => {
1295                                 let f = || {
1296                                         let mut payment_hash = PaymentHash([0; 32]);
1297                                         let mut payment_id = PaymentId([0; 32]);
1298                                         let mut reason = None;
1299                                         read_tlv_fields!(reader, {
1300                                                 (0, payment_id, required),
1301                                                 (1, reason, upgradable_option),
1302                                                 (2, payment_hash, required),
1303                                         });
1304                                         Ok(Some(Event::PaymentFailed {
1305                                                 payment_id,
1306                                                 payment_hash,
1307                                                 reason,
1308                                         }))
1309                                 };
1310                                 f()
1311                         },
1312                         17u8 => {
1313                                 // Value 17 is used for `Event::OpenChannelRequest`.
1314                                 Ok(None)
1315                         },
1316                         19u8 => {
1317                                 let f = || {
1318                                         let mut payment_hash = PaymentHash([0; 32]);
1319                                         let mut purpose = UpgradableRequired(None);
1320                                         let mut amount_msat = 0;
1321                                         let mut receiver_node_id = None;
1322                                         read_tlv_fields!(reader, {
1323                                                 (0, payment_hash, required),
1324                                                 (1, receiver_node_id, option),
1325                                                 (2, purpose, upgradable_required),
1326                                                 (4, amount_msat, required),
1327                                         });
1328                                         Ok(Some(Event::PaymentClaimed {
1329                                                 receiver_node_id,
1330                                                 payment_hash,
1331                                                 purpose: _init_tlv_based_struct_field!(purpose, upgradable_required),
1332                                                 amount_msat,
1333                                         }))
1334                                 };
1335                                 f()
1336                         },
1337                         21u8 => {
1338                                 let f = || {
1339                                         _init_and_read_tlv_fields!(reader, {
1340                                                 (0, payment_id, required),
1341                                                 (2, payment_hash, required),
1342                                                 (4, path, vec_type),
1343                                                 (6, blinded_tail, option),
1344                                         });
1345                                         Ok(Some(Event::ProbeSuccessful {
1346                                                 payment_id: payment_id.0.unwrap(),
1347                                                 payment_hash: payment_hash.0.unwrap(),
1348                                                 path: Path { hops: path.unwrap(), blinded_tail },
1349                                         }))
1350                                 };
1351                                 f()
1352                         },
1353                         23u8 => {
1354                                 let f = || {
1355                                         _init_and_read_tlv_fields!(reader, {
1356                                                 (0, payment_id, required),
1357                                                 (2, payment_hash, required),
1358                                                 (4, path, vec_type),
1359                                                 (6, short_channel_id, option),
1360                                                 (8, blinded_tail, option),
1361                                         });
1362                                         Ok(Some(Event::ProbeFailed {
1363                                                 payment_id: payment_id.0.unwrap(),
1364                                                 payment_hash: payment_hash.0.unwrap(),
1365                                                 path: Path { hops: path.unwrap(), blinded_tail },
1366                                                 short_channel_id,
1367                                         }))
1368                                 };
1369                                 f()
1370                         },
1371                         25u8 => {
1372                                 let f = || {
1373                                         let mut prev_channel_id = [0; 32];
1374                                         let mut failed_next_destination_opt = UpgradableRequired(None);
1375                                         read_tlv_fields!(reader, {
1376                                                 (0, prev_channel_id, required),
1377                                                 (2, failed_next_destination_opt, upgradable_required),
1378                                         });
1379                                         Ok(Some(Event::HTLCHandlingFailed {
1380                                                 prev_channel_id,
1381                                                 failed_next_destination: _init_tlv_based_struct_field!(failed_next_destination_opt, upgradable_required),
1382                                         }))
1383                                 };
1384                                 f()
1385                         },
1386                         27u8 => Ok(None),
1387                         29u8 => {
1388                                 let f = || {
1389                                         let mut channel_id = [0; 32];
1390                                         let mut user_channel_id: u128 = 0;
1391                                         let mut counterparty_node_id = RequiredWrapper(None);
1392                                         let mut channel_type = RequiredWrapper(None);
1393                                         read_tlv_fields!(reader, {
1394                                                 (0, channel_id, required),
1395                                                 (2, user_channel_id, required),
1396                                                 (4, counterparty_node_id, required),
1397                                                 (6, channel_type, required),
1398                                         });
1399
1400                                         Ok(Some(Event::ChannelReady {
1401                                                 channel_id,
1402                                                 user_channel_id,
1403                                                 counterparty_node_id: counterparty_node_id.0.unwrap(),
1404                                                 channel_type: channel_type.0.unwrap()
1405                                         }))
1406                                 };
1407                                 f()
1408                         },
1409                         31u8 => {
1410                                 let f = || {
1411                                         let mut channel_id = [0; 32];
1412                                         let mut user_channel_id: u128 = 0;
1413                                         let mut former_temporary_channel_id = None;
1414                                         let mut counterparty_node_id = RequiredWrapper(None);
1415                                         let mut funding_txo = RequiredWrapper(None);
1416                                         read_tlv_fields!(reader, {
1417                                                 (0, channel_id, required),
1418                                                 (2, user_channel_id, required),
1419                                                 (4, former_temporary_channel_id, required),
1420                                                 (6, counterparty_node_id, required),
1421                                                 (8, funding_txo, required),
1422                                         });
1423
1424                                         Ok(Some(Event::ChannelPending {
1425                                                 channel_id,
1426                                                 user_channel_id,
1427                                                 former_temporary_channel_id,
1428                                                 counterparty_node_id: counterparty_node_id.0.unwrap(),
1429                                                 funding_txo: funding_txo.0.unwrap()
1430                                         }))
1431                                 };
1432                                 f()
1433                         },
1434                         // Versions prior to 0.0.100 did not ignore odd types, instead returning InvalidValue.
1435                         // Version 0.0.100 failed to properly ignore odd types, possibly resulting in corrupt
1436                         // reads.
1437                         x if x % 2 == 1 => {
1438                                 // If the event is of unknown type, assume it was written with `write_tlv_fields`,
1439                                 // which prefixes the whole thing with a length BigSize. Because the event is
1440                                 // odd-type unknown, we should treat it as `Ok(None)` even if it has some TLV
1441                                 // fields that are even. Thus, we avoid using `read_tlv_fields` and simply read
1442                                 // exactly the number of bytes specified, ignoring them entirely.
1443                                 let tlv_len: BigSize = Readable::read(reader)?;
1444                                 FixedLengthReader::new(reader, tlv_len.0)
1445                                         .eat_remaining().map_err(|_| msgs::DecodeError::ShortRead)?;
1446                                 Ok(None)
1447                         },
1448                         _ => Err(msgs::DecodeError::InvalidValue)
1449                 }
1450         }
1451 }
1452
1453 /// An event generated by ChannelManager which indicates a message should be sent to a peer (or
1454 /// broadcast to most peers).
1455 /// These events are handled by PeerManager::process_events if you are using a PeerManager.
1456 #[derive(Clone, Debug)]
1457 pub enum MessageSendEvent {
1458         /// Used to indicate that we've accepted a channel open and should send the accept_channel
1459         /// message provided to the given peer.
1460         SendAcceptChannel {
1461                 /// The node_id of the node which should receive this message
1462                 node_id: PublicKey,
1463                 /// The message which should be sent.
1464                 msg: msgs::AcceptChannel,
1465         },
1466         /// Used to indicate that we've accepted a V2 channel open and should send the accept_channel2
1467         /// message provided to the given peer.
1468         SendAcceptChannelV2 {
1469                 /// The node_id of the node which should receive this message
1470                 node_id: PublicKey,
1471                 /// The message which should be sent.
1472                 msg: msgs::AcceptChannelV2,
1473         },
1474         /// Used to indicate that we've initiated a channel open and should send the open_channel
1475         /// message provided to the given peer.
1476         SendOpenChannel {
1477                 /// The node_id of the node which should receive this message
1478                 node_id: PublicKey,
1479                 /// The message which should be sent.
1480                 msg: msgs::OpenChannel,
1481         },
1482         /// Used to indicate that we've initiated a V2 channel open and should send the open_channel2
1483         /// message provided to the given peer.
1484         SendOpenChannelV2 {
1485                 /// The node_id of the node which should receive this message
1486                 node_id: PublicKey,
1487                 /// The message which should be sent.
1488                 msg: msgs::OpenChannelV2,
1489         },
1490         /// Used to indicate that a funding_created message should be sent to the peer with the given node_id.
1491         SendFundingCreated {
1492                 /// The node_id of the node which should receive this message
1493                 node_id: PublicKey,
1494                 /// The message which should be sent.
1495                 msg: msgs::FundingCreated,
1496         },
1497         /// Used to indicate that a funding_signed message should be sent to the peer with the given node_id.
1498         SendFundingSigned {
1499                 /// The node_id of the node which should receive this message
1500                 node_id: PublicKey,
1501                 /// The message which should be sent.
1502                 msg: msgs::FundingSigned,
1503         },
1504         /// Used to indicate that a tx_add_input message should be sent to the peer with the given node_id.
1505         SendTxAddInput {
1506                 /// The node_id of the node which should receive this message
1507                 node_id: PublicKey,
1508                 /// The message which should be sent.
1509                 msg: msgs::TxAddInput,
1510         },
1511         /// Used to indicate that a tx_add_output message should be sent to the peer with the given node_id.
1512         SendTxAddOutput {
1513                 /// The node_id of the node which should receive this message
1514                 node_id: PublicKey,
1515                 /// The message which should be sent.
1516                 msg: msgs::TxAddOutput,
1517         },
1518         /// Used to indicate that a tx_remove_input message should be sent to the peer with the given node_id.
1519         SendTxRemoveInput {
1520                 /// The node_id of the node which should receive this message
1521                 node_id: PublicKey,
1522                 /// The message which should be sent.
1523                 msg: msgs::TxRemoveInput,
1524         },
1525         /// Used to indicate that a tx_remove_output message should be sent to the peer with the given node_id.
1526         SendTxRemoveOutput {
1527                 /// The node_id of the node which should receive this message
1528                 node_id: PublicKey,
1529                 /// The message which should be sent.
1530                 msg: msgs::TxRemoveOutput,
1531         },
1532         /// Used to indicate that a tx_complete message should be sent to the peer with the given node_id.
1533         SendTxComplete {
1534                 /// The node_id of the node which should receive this message
1535                 node_id: PublicKey,
1536                 /// The message which should be sent.
1537                 msg: msgs::TxComplete,
1538         },
1539         /// Used to indicate that a tx_signatures message should be sent to the peer with the given node_id.
1540         SendTxSignatures {
1541                 /// The node_id of the node which should receive this message
1542                 node_id: PublicKey,
1543                 /// The message which should be sent.
1544                 msg: msgs::TxSignatures,
1545         },
1546         /// Used to indicate that a tx_init_rbf message should be sent to the peer with the given node_id.
1547         SendTxInitRbf {
1548                 /// The node_id of the node which should receive this message
1549                 node_id: PublicKey,
1550                 /// The message which should be sent.
1551                 msg: msgs::TxInitRbf,
1552         },
1553         /// Used to indicate that a tx_ack_rbf message should be sent to the peer with the given node_id.
1554         SendTxAckRbf {
1555                 /// The node_id of the node which should receive this message
1556                 node_id: PublicKey,
1557                 /// The message which should be sent.
1558                 msg: msgs::TxAckRbf,
1559         },
1560         /// Used to indicate that a tx_abort message should be sent to the peer with the given node_id.
1561         SendTxAbort {
1562                 /// The node_id of the node which should receive this message
1563                 node_id: PublicKey,
1564                 /// The message which should be sent.
1565                 msg: msgs::TxAddInput,
1566         },
1567         /// Used to indicate that a channel_ready message should be sent to the peer with the given node_id.
1568         SendChannelReady {
1569                 /// The node_id of the node which should receive these message(s)
1570                 node_id: PublicKey,
1571                 /// The channel_ready message which should be sent.
1572                 msg: msgs::ChannelReady,
1573         },
1574         /// Used to indicate that an announcement_signatures message should be sent to the peer with the given node_id.
1575         SendAnnouncementSignatures {
1576                 /// The node_id of the node which should receive these message(s)
1577                 node_id: PublicKey,
1578                 /// The announcement_signatures message which should be sent.
1579                 msg: msgs::AnnouncementSignatures,
1580         },
1581         /// Used to indicate that a series of HTLC update messages, as well as a commitment_signed
1582         /// message should be sent to the peer with the given node_id.
1583         UpdateHTLCs {
1584                 /// The node_id of the node which should receive these message(s)
1585                 node_id: PublicKey,
1586                 /// The update messages which should be sent. ALL messages in the struct should be sent!
1587                 updates: msgs::CommitmentUpdate,
1588         },
1589         /// Used to indicate that a revoke_and_ack message should be sent to the peer with the given node_id.
1590         SendRevokeAndACK {
1591                 /// The node_id of the node which should receive this message
1592                 node_id: PublicKey,
1593                 /// The message which should be sent.
1594                 msg: msgs::RevokeAndACK,
1595         },
1596         /// Used to indicate that a closing_signed message should be sent to the peer with the given node_id.
1597         SendClosingSigned {
1598                 /// The node_id of the node which should receive this message
1599                 node_id: PublicKey,
1600                 /// The message which should be sent.
1601                 msg: msgs::ClosingSigned,
1602         },
1603         /// Used to indicate that a shutdown message should be sent to the peer with the given node_id.
1604         SendShutdown {
1605                 /// The node_id of the node which should receive this message
1606                 node_id: PublicKey,
1607                 /// The message which should be sent.
1608                 msg: msgs::Shutdown,
1609         },
1610         /// Used to indicate that a channel_reestablish message should be sent to the peer with the given node_id.
1611         SendChannelReestablish {
1612                 /// The node_id of the node which should receive this message
1613                 node_id: PublicKey,
1614                 /// The message which should be sent.
1615                 msg: msgs::ChannelReestablish,
1616         },
1617         /// Used to send a channel_announcement and channel_update to a specific peer, likely on
1618         /// initial connection to ensure our peers know about our channels.
1619         SendChannelAnnouncement {
1620                 /// The node_id of the node which should receive this message
1621                 node_id: PublicKey,
1622                 /// The channel_announcement which should be sent.
1623                 msg: msgs::ChannelAnnouncement,
1624                 /// The followup channel_update which should be sent.
1625                 update_msg: msgs::ChannelUpdate,
1626         },
1627         /// Used to indicate that a channel_announcement and channel_update should be broadcast to all
1628         /// peers (except the peer with node_id either msg.contents.node_id_1 or msg.contents.node_id_2).
1629         ///
1630         /// Note that after doing so, you very likely (unless you did so very recently) want to
1631         /// broadcast a node_announcement (e.g. via [`PeerManager::broadcast_node_announcement`]). This
1632         /// ensures that any nodes which see our channel_announcement also have a relevant
1633         /// node_announcement, including relevant feature flags which may be important for routing
1634         /// through or to us.
1635         ///
1636         /// [`PeerManager::broadcast_node_announcement`]: crate::ln::peer_handler::PeerManager::broadcast_node_announcement
1637         BroadcastChannelAnnouncement {
1638                 /// The channel_announcement which should be sent.
1639                 msg: msgs::ChannelAnnouncement,
1640                 /// The followup channel_update which should be sent.
1641                 update_msg: Option<msgs::ChannelUpdate>,
1642         },
1643         /// Used to indicate that a channel_update should be broadcast to all peers.
1644         BroadcastChannelUpdate {
1645                 /// The channel_update which should be sent.
1646                 msg: msgs::ChannelUpdate,
1647         },
1648         /// Used to indicate that a node_announcement should be broadcast to all peers.
1649         BroadcastNodeAnnouncement {
1650                 /// The node_announcement which should be sent.
1651                 msg: msgs::NodeAnnouncement,
1652         },
1653         /// Used to indicate that a channel_update should be sent to a single peer.
1654         /// In contrast to [`Self::BroadcastChannelUpdate`], this is used when the channel is a
1655         /// private channel and we shouldn't be informing all of our peers of channel parameters.
1656         SendChannelUpdate {
1657                 /// The node_id of the node which should receive this message
1658                 node_id: PublicKey,
1659                 /// The channel_update which should be sent.
1660                 msg: msgs::ChannelUpdate,
1661         },
1662         /// Broadcast an error downstream to be handled
1663         HandleError {
1664                 /// The node_id of the node which should receive this message
1665                 node_id: PublicKey,
1666                 /// The action which should be taken.
1667                 action: msgs::ErrorAction
1668         },
1669         /// Query a peer for channels with funding transaction UTXOs in a block range.
1670         SendChannelRangeQuery {
1671                 /// The node_id of this message recipient
1672                 node_id: PublicKey,
1673                 /// The query_channel_range which should be sent.
1674                 msg: msgs::QueryChannelRange,
1675         },
1676         /// Request routing gossip messages from a peer for a list of channels identified by
1677         /// their short_channel_ids.
1678         SendShortIdsQuery {
1679                 /// The node_id of this message recipient
1680                 node_id: PublicKey,
1681                 /// The query_short_channel_ids which should be sent.
1682                 msg: msgs::QueryShortChannelIds,
1683         },
1684         /// Sends a reply to a channel range query. This may be one of several SendReplyChannelRange events
1685         /// emitted during processing of the query.
1686         SendReplyChannelRange {
1687                 /// The node_id of this message recipient
1688                 node_id: PublicKey,
1689                 /// The reply_channel_range which should be sent.
1690                 msg: msgs::ReplyChannelRange,
1691         },
1692         /// Sends a timestamp filter for inbound gossip. This should be sent on each new connection to
1693         /// enable receiving gossip messages from the peer.
1694         SendGossipTimestampFilter {
1695                 /// The node_id of this message recipient
1696                 node_id: PublicKey,
1697                 /// The gossip_timestamp_filter which should be sent.
1698                 msg: msgs::GossipTimestampFilter,
1699         },
1700 }
1701
1702 /// A trait indicating an object may generate message send events
1703 pub trait MessageSendEventsProvider {
1704         /// Gets the list of pending events which were generated by previous actions, clearing the list
1705         /// in the process.
1706         fn get_and_clear_pending_msg_events(&self) -> Vec<MessageSendEvent>;
1707 }
1708
1709 /// A trait indicating an object may generate onion messages to send
1710 pub trait OnionMessageProvider {
1711         /// Gets the next pending onion message for the peer with the given node id.
1712         fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<msgs::OnionMessage>;
1713 }
1714
1715 /// A trait indicating an object may generate events.
1716 ///
1717 /// Events are processed by passing an [`EventHandler`] to [`process_pending_events`].
1718 ///
1719 /// Implementations of this trait may also feature an async version of event handling, as shown with
1720 /// [`ChannelManager::process_pending_events_async`] and
1721 /// [`ChainMonitor::process_pending_events_async`].
1722 ///
1723 /// # Requirements
1724 ///
1725 /// When using this trait, [`process_pending_events`] will call [`handle_event`] for each pending
1726 /// event since the last invocation.
1727 ///
1728 /// In order to ensure no [`Event`]s are lost, implementors of this trait will persist [`Event`]s
1729 /// and replay any unhandled events on startup. An [`Event`] is considered handled when
1730 /// [`process_pending_events`] returns, thus handlers MUST fully handle [`Event`]s and persist any
1731 /// relevant changes to disk *before* returning.
1732 ///
1733 /// Further, because an application may crash between an [`Event`] being handled and the
1734 /// implementor of this trait being re-serialized, [`Event`] handling must be idempotent - in
1735 /// effect, [`Event`]s may be replayed.
1736 ///
1737 /// Note, handlers may call back into the provider and thus deadlocking must be avoided. Be sure to
1738 /// consult the provider's documentation on the implication of processing events and how a handler
1739 /// may safely use the provider (e.g., see [`ChannelManager::process_pending_events`] and
1740 /// [`ChainMonitor::process_pending_events`]).
1741 ///
1742 /// (C-not implementable) As there is likely no reason for a user to implement this trait on their
1743 /// own type(s).
1744 ///
1745 /// [`process_pending_events`]: Self::process_pending_events
1746 /// [`handle_event`]: EventHandler::handle_event
1747 /// [`ChannelManager::process_pending_events`]: crate::ln::channelmanager::ChannelManager#method.process_pending_events
1748 /// [`ChainMonitor::process_pending_events`]: crate::chain::chainmonitor::ChainMonitor#method.process_pending_events
1749 /// [`ChannelManager::process_pending_events_async`]: crate::ln::channelmanager::ChannelManager::process_pending_events_async
1750 /// [`ChainMonitor::process_pending_events_async`]: crate::chain::chainmonitor::ChainMonitor::process_pending_events_async
1751 pub trait EventsProvider {
1752         /// Processes any events generated since the last call using the given event handler.
1753         ///
1754         /// See the trait-level documentation for requirements.
1755         fn process_pending_events<H: Deref>(&self, handler: H) where H::Target: EventHandler;
1756 }
1757
1758 /// A trait implemented for objects handling events from [`EventsProvider`].
1759 ///
1760 /// An async variation also exists for implementations of [`EventsProvider`] that support async
1761 /// event handling. The async event handler should satisfy the generic bounds: `F:
1762 /// core::future::Future, H: Fn(Event) -> F`.
1763 pub trait EventHandler {
1764         /// Handles the given [`Event`].
1765         ///
1766         /// See [`EventsProvider`] for details that must be considered when implementing this method.
1767         fn handle_event(&self, event: Event);
1768 }
1769
1770 impl<F> EventHandler for F where F: Fn(Event) {
1771         fn handle_event(&self, event: Event) {
1772                 self(event)
1773         }
1774 }
1775
1776 impl<T: EventHandler> EventHandler for Arc<T> {
1777         fn handle_event(&self, event: Event) {
1778                 self.deref().handle_event(event)
1779         }
1780 }