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

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