Actual no_std support
[rust-lightning] / lightning / src / util / events.rs
index 271b6ddd13e71c0c58ddb1299dc6431970e0f08b..74490eb348b6f78eff96088b4db81b24ce1432ad 100644 (file)
 //! few other things.
 
 use ln::msgs;
-use ln::channelmanager::{PaymentPreimage, PaymentHash, PaymentSecret};
-use chain::transaction::OutPoint;
+use ln::{PaymentPreimage, PaymentHash, PaymentSecret};
 use chain::keysinterface::SpendableOutputDescriptor;
-use util::ser::{Writeable, Writer, MaybeReadable, Readable};
+use util::ser::{Writeable, Writer, MaybeReadable, Readable, VecReadWrapper, VecWriteWrapper};
 
 use bitcoin::blockdata::script::Script;
 
 use bitcoin::secp256k1::key::PublicKey;
 
-use std::time::Duration;
+use io;
+use prelude::*;
+use core::time::Duration;
+use core::ops::Deref;
+
+/// Some information provided on receipt of payment depends on whether the payment received is a
+/// spontaneous payment or a "conventional" lightning payment that's paying an invoice.
+#[derive(Clone, Debug)]
+pub enum PaymentPurpose {
+       /// Information for receiving a payment that we generated an invoice for.
+       InvoicePayment {
+               /// The preimage to the payment_hash, if the payment hash (and secret) were fetched via
+               /// [`ChannelManager::create_inbound_payment`]. If provided, this can be handed directly to
+               /// [`ChannelManager::claim_funds`].
+               ///
+               /// [`ChannelManager::create_inbound_payment`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment
+               /// [`ChannelManager::claim_funds`]: crate::ln::channelmanager::ChannelManager::claim_funds
+               payment_preimage: Option<PaymentPreimage>,
+               /// The "payment secret". This authenticates the sender to the recipient, preventing a
+               /// number of deanonymization attacks during the routing process.
+               /// It is provided here for your reference, however its accuracy is enforced directly by
+               /// [`ChannelManager`] using the values you previously provided to
+               /// [`ChannelManager::create_inbound_payment`] or
+               /// [`ChannelManager::create_inbound_payment_for_hash`].
+               ///
+               /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
+               /// [`ChannelManager::create_inbound_payment`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment
+               /// [`ChannelManager::create_inbound_payment_for_hash`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment_for_hash
+               payment_secret: PaymentSecret,
+               /// This is the `user_payment_id` which was provided to
+               /// [`ChannelManager::create_inbound_payment_for_hash`] or
+               /// [`ChannelManager::create_inbound_payment`]. It has no meaning inside of LDK and is
+               /// simply copied here. It may be used to correlate PaymentReceived events with invoice
+               /// metadata stored elsewhere.
+               ///
+               /// [`ChannelManager::create_inbound_payment`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment
+               /// [`ChannelManager::create_inbound_payment_for_hash`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment_for_hash
+               user_payment_id: u64,
+       },
+       /// Because this is a spontaneous payment, the payer generated their own preimage rather than us
+       /// (the payee) providing a preimage.
+       SpontaneousPayment(PaymentPreimage),
+}
 
 /// An Event which you should probably take some action in response to.
 ///
@@ -49,16 +90,6 @@ pub enum Event {
                /// The value passed in to ChannelManager::create_channel
                user_channel_id: u64,
        },
-       /// Used to indicate that the client may now broadcast the funding transaction it created for a
-       /// channel. Broadcasting such a transaction prior to this event may lead to our counterparty
-       /// trivially stealing all funds in the funding transaction!
-       FundingBroadcastSafe {
-               /// The output, which was passed to ChannelManager::funding_transaction_generated, which is
-               /// now safe to broadcast.
-               funding_txo: OutPoint,
-               /// The value passed in to ChannelManager::create_channel
-               user_channel_id: u64,
-       },
        /// Indicates we've received money! Just gotta dig out that payment preimage and feed it to
        /// ChannelManager::claim_funds to get it....
        /// Note that if the preimage is not known or the amount paid is incorrect, you should call
@@ -72,25 +103,16 @@ pub enum Event {
        PaymentReceived {
                /// The hash for which the preimage should be handed to the ChannelManager.
                payment_hash: PaymentHash,
-               /// The "payment secret". This authenticates the sender to the recipient, preventing a
-               /// number of deanonymization attacks during the routing process.
-               /// As nodes upgrade, the invoices you provide should likely migrate to setting the
-               /// payment_secret feature to required, at which point you should fail_backwards any HTLCs
-               /// which have a None here.
-               /// Until then, however, values of None should be ignored, and only incorrect Some values
-               /// should result in an HTLC fail_backwards.
-               /// Note that, in any case, this value must be passed as-is to any fail or claim calls as
-               /// the HTLC index includes this value.
-               payment_secret: Option<PaymentSecret>,
                /// The value, in thousandths of a satoshi, that this payment is for. Note that you must
                /// compare this to the expected value before accepting the payment (as otherwise you are
                /// providing proof-of-payment for less than the value you expected!).
                amt: u64,
+               /// Information for claiming this received payment, based on whether the purpose of the
+               /// payment is to pay an invoice or to send a spontaneous payment.
+               purpose: PaymentPurpose,
        },
        /// Indicates an outbound payment we made succeeded (ie it made it all the way to its target
        /// and we got back the payment preimage for it).
-       /// Note that duplicative PaymentSent Events may be generated - it is your responsibility to
-       /// deduplicate them by payment_preimage (which MUST be unique)!
        PaymentSent {
                /// The preimage to the hash given to ChannelManager::send_payment.
                /// Note that this serves as a payment receipt, if you wish to have such a thing, you must
@@ -99,8 +121,6 @@ pub enum Event {
        },
        /// Indicates an outbound payment we made failed. Probably some intermediary node dropped
        /// something. You may wish to retry with a different route.
-       /// Note that duplicative PaymentFailed Events may be generated - it is your responsibility to
-       /// deduplicate them by payment_hash (which MUST be unique)!
        PaymentFailed {
                /// The hash which was given to ChannelManager::send_payment.
                payment_hash: PaymentHash,
@@ -122,7 +142,8 @@ pub enum Event {
                /// now + 5*time_forwardable).
                time_forwardable: Duration,
        },
-       /// Used to indicate that an output was generated on-chain which you should know how to spend.
+       /// Used to indicate that an output which you should know how to spend was confirmed on chain
+       /// and is now spendable.
        /// Such an output will *not* ever be spent by rust-lightning, and are not at risk of your
        /// counterparty spending them due to some kind of timeout. Thus, you need to store them
        /// somewhere and spend them when you create on-chain transactions.
@@ -133,27 +154,41 @@ pub enum Event {
 }
 
 impl Writeable for Event {
-       fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
+       fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
                match self {
                        &Event::FundingGenerationReady { .. } => {
                                0u8.write(writer)?;
                                // We never write out FundingGenerationReady events as, upon disconnection, peers
                                // drop any channels which have not yet exchanged funding_signed.
                        },
-                       &Event::FundingBroadcastSafe { ref funding_txo, ref user_channel_id } => {
+                       &Event::PaymentReceived { ref payment_hash, ref amt, ref purpose } => {
                                1u8.write(writer)?;
-                               funding_txo.write(writer)?;
-                               user_channel_id.write(writer)?;
-                       },
-                       &Event::PaymentReceived { ref payment_hash, ref payment_secret, ref amt } => {
-                               2u8.write(writer)?;
-                               payment_hash.write(writer)?;
-                               payment_secret.write(writer)?;
-                               amt.write(writer)?;
+                               let mut payment_secret = None;
+                               let mut user_payment_id = None;
+                               let payment_preimage;
+                               match &purpose {
+                                       PaymentPurpose::InvoicePayment { payment_preimage: preimage, payment_secret: secret, user_payment_id: id } => {
+                                               payment_secret = Some(secret);
+                                               payment_preimage = *preimage;
+                                               user_payment_id = Some(id);
+                                       },
+                                       PaymentPurpose::SpontaneousPayment(preimage) => {
+                                               payment_preimage = Some(*preimage);
+                                       }
+                               }
+                               write_tlv_fields!(writer, {
+                                       (0, payment_hash, required),
+                                       (2, payment_secret, option),
+                                       (4, amt, required),
+                                       (6, user_payment_id, option),
+                                       (8, payment_preimage, option),
+                               });
                        },
                        &Event::PaymentSent { ref payment_preimage } => {
-                               3u8.write(writer)?;
-                               payment_preimage.write(writer)?;
+                               2u8.write(writer)?;
+                               write_tlv_fields!(writer, {
+                                       (0, payment_preimage, required),
+                               });
                        },
                        &Event::PaymentFailed { ref payment_hash, ref rejected_by_dest,
                                #[cfg(test)]
@@ -161,64 +196,122 @@ impl Writeable for Event {
                                #[cfg(test)]
                                ref error_data,
                        } => {
-                               4u8.write(writer)?;
-                               payment_hash.write(writer)?;
-                               rejected_by_dest.write(writer)?;
+                               3u8.write(writer)?;
                                #[cfg(test)]
                                error_code.write(writer)?;
                                #[cfg(test)]
                                error_data.write(writer)?;
+                               write_tlv_fields!(writer, {
+                                       (0, payment_hash, required),
+                                       (2, rejected_by_dest, required),
+                               });
                        },
                        &Event::PendingHTLCsForwardable { time_forwardable: _ } => {
-                               5u8.write(writer)?;
+                               4u8.write(writer)?;
+                               write_tlv_fields!(writer, {});
                                // We don't write the time_fordwardable out at all, as we presume when the user
                                // deserializes us at least that much time has elapsed.
                        },
                        &Event::SpendableOutputs { ref outputs } => {
-                               6u8.write(writer)?;
-                               (outputs.len() as u64).write(writer)?;
-                               for output in outputs.iter() {
-                                       output.write(writer)?;
-                               }
+                               5u8.write(writer)?;
+                               write_tlv_fields!(writer, {
+                                       (0, VecWriteWrapper(outputs), required),
+                               });
                        },
                }
                Ok(())
        }
 }
 impl MaybeReadable for Event {
-       fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Option<Self>, msgs::DecodeError> {
+       fn read<R: io::Read>(reader: &mut R) -> Result<Option<Self>, msgs::DecodeError> {
                match Readable::read(reader)? {
                        0u8 => Ok(None),
-                       1u8 => Ok(Some(Event::FundingBroadcastSafe {
-                                       funding_txo: Readable::read(reader)?,
-                                       user_channel_id: Readable::read(reader)?,
-                               })),
-                       2u8 => Ok(Some(Event::PaymentReceived {
-                                       payment_hash: Readable::read(reader)?,
-                                       payment_secret: Readable::read(reader)?,
-                                       amt: Readable::read(reader)?,
-                               })),
-                       3u8 => Ok(Some(Event::PaymentSent {
-                                       payment_preimage: Readable::read(reader)?,
-                               })),
-                       4u8 => Ok(Some(Event::PaymentFailed {
-                                       payment_hash: Readable::read(reader)?,
-                                       rejected_by_dest: Readable::read(reader)?,
+                       1u8 => {
+                               let f = || {
+                                       let mut payment_hash = PaymentHash([0; 32]);
+                                       let mut payment_preimage = None;
+                                       let mut payment_secret = None;
+                                       let mut amt = 0;
+                                       let mut user_payment_id = None;
+                                       read_tlv_fields!(reader, {
+                                               (0, payment_hash, required),
+                                               (2, payment_secret, option),
+                                               (4, amt, required),
+                                               (6, user_payment_id, option),
+                                               (8, payment_preimage, option),
+                                       });
+                                       let purpose = match payment_secret {
+                                               Some(secret) => PaymentPurpose::InvoicePayment {
+                                                       payment_preimage,
+                                                       payment_secret: secret,
+                                                       user_payment_id: if let Some(id) = user_payment_id {
+                                                               id
+                                                       } else { return Err(msgs::DecodeError::InvalidValue) }
+                                               },
+                                               None if payment_preimage.is_some() => PaymentPurpose::SpontaneousPayment(payment_preimage.unwrap()),
+                                               None => return Err(msgs::DecodeError::InvalidValue),
+                                       };
+                                       Ok(Some(Event::PaymentReceived {
+                                               payment_hash,
+                                               amt,
+                                               purpose,
+                                       }))
+                               };
+                               f()
+                       },
+                       2u8 => {
+                               let f = || {
+                                       let mut payment_preimage = PaymentPreimage([0; 32]);
+                                       read_tlv_fields!(reader, {
+                                               (0, payment_preimage, required),
+                                       });
+                                       Ok(Some(Event::PaymentSent {
+                                               payment_preimage,
+                                       }))
+                               };
+                               f()
+                       },
+                       3u8 => {
+                               let f = || {
                                        #[cfg(test)]
-                                       error_code: Readable::read(reader)?,
+                                       let error_code = Readable::read(reader)?;
                                        #[cfg(test)]
-                                       error_data: Readable::read(reader)?,
-                               })),
-                       5u8 => Ok(Some(Event::PendingHTLCsForwardable {
-                                       time_forwardable: Duration::from_secs(0)
-                               })),
-                       6u8 => {
-                               let outputs_len: u64 = Readable::read(reader)?;
-                               let mut outputs = Vec::new();
-                               for _ in 0..outputs_len {
-                                       outputs.push(Readable::read(reader)?);
-                               }
-                               Ok(Some(Event::SpendableOutputs { outputs }))
+                                       let error_data = Readable::read(reader)?;
+                                       let mut payment_hash = PaymentHash([0; 32]);
+                                       let mut rejected_by_dest = false;
+                                       read_tlv_fields!(reader, {
+                                               (0, payment_hash, required),
+                                               (2, rejected_by_dest, required),
+                                       });
+                                       Ok(Some(Event::PaymentFailed {
+                                               payment_hash,
+                                               rejected_by_dest,
+                                               #[cfg(test)]
+                                               error_code,
+                                               #[cfg(test)]
+                                               error_data,
+                                       }))
+                               };
+                               f()
+                       },
+                       4u8 => {
+                               let f = || {
+                                       read_tlv_fields!(reader, {});
+                                       Ok(Some(Event::PendingHTLCsForwardable {
+                                               time_forwardable: Duration::from_secs(0)
+                                       }))
+                               };
+                               f()
+                       },
+                       5u8 => {
+                               let f = || {
+                                       let mut outputs = VecReadWrapper(Vec::new());
+                                       read_tlv_fields!(reader, {
+                                               (0, outputs, required),
+                                       });
+                                       Ok(Some(Event::SpendableOutputs { outputs: outputs.0 }))
+                               };
+                               f()
                        },
                        _ => Err(msgs::DecodeError::InvalidValue)
                }
@@ -228,7 +321,7 @@ impl MaybeReadable for Event {
 /// An event generated by ChannelManager which indicates a message should be sent to a peer (or
 /// broadcast to most peers).
 /// These events are handled by PeerManager::process_events if you are using a PeerManager.
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 pub enum MessageSendEvent {
        /// Used to indicate that we've accepted a channel open and should send the accept_channel
        /// message provided to the given peer.
@@ -334,6 +427,15 @@ pub enum MessageSendEvent {
                /// The channel_update which should be sent.
                msg: msgs::ChannelUpdate,
        },
+       /// Used to indicate that a channel_update should be sent to a single peer.
+       /// In contrast to [`Self::BroadcastChannelUpdate`], this is used when the channel is a
+       /// private channel and we shouldn't be informing all of our peers of channel parameters.
+       SendChannelUpdate {
+               /// The node_id of the node which should receive this message
+               node_id: PublicKey,
+               /// The channel_update which should be sent.
+               msg: msgs::ChannelUpdate,
+       },
        /// Broadcast an error downstream to be handled
        HandleError {
                /// The node_id of the node which should receive this message
@@ -379,9 +481,49 @@ pub trait MessageSendEventsProvider {
        fn get_and_clear_pending_msg_events(&self) -> Vec<MessageSendEvent>;
 }
 
-/// A trait indicating an object may generate events
+/// A trait indicating an object may generate events.
+///
+/// Events are processed by passing an [`EventHandler`] to [`process_pending_events`].
+///
+/// # Requirements
+///
+/// See [`process_pending_events`] for requirements around event processing.
+///
+/// When using this trait, [`process_pending_events`] will call [`handle_event`] for each pending
+/// event since the last invocation. The handler must either act upon the event immediately
+/// or preserve it for later handling.
+///
+/// Note, handlers may call back into the provider and thus deadlocking must be avoided. Be sure to
+/// consult the provider's documentation on the implication of processing events and how a handler
+/// may safely use the provider (e.g., see [`ChannelManager::process_pending_events`] and
+/// [`ChainMonitor::process_pending_events`]).
+///
+/// (C-not implementable) As there is likely no reason for a user to implement this trait on their
+/// own type(s).
+///
+/// [`process_pending_events`]: Self::process_pending_events
+/// [`handle_event`]: EventHandler::handle_event
+/// [`ChannelManager::process_pending_events`]: crate::ln::channelmanager::ChannelManager#method.process_pending_events
+/// [`ChainMonitor::process_pending_events`]: crate::chain::chainmonitor::ChainMonitor#method.process_pending_events
 pub trait EventsProvider {
-       /// Gets the list of pending events which were generated by previous actions, clearing the list
-       /// in the process.
-       fn get_and_clear_pending_events(&self) -> Vec<Event>;
+       /// Processes any events generated since the last call using the given event handler.
+       ///
+       /// Subsequent calls must only process new events. However, handlers must be capable of handling
+       /// duplicate events across process restarts. This may occur if the provider was recovered from
+       /// an old state (i.e., it hadn't been successfully persisted after processing pending events).
+       fn process_pending_events<H: Deref>(&self, handler: H) where H::Target: EventHandler;
+}
+
+/// A trait implemented for objects handling events from [`EventsProvider`].
+pub trait EventHandler {
+       /// Handles the given [`Event`].
+       ///
+       /// See [`EventsProvider`] for details that must be considered when implementing this method.
+       fn handle_event(&self, event: Event);
+}
+
+impl<F> EventHandler for F where F: Fn(Event) {
+       fn handle_event(&self, event: Event) {
+               self(event)
+       }
 }