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Hold ChannelManager locks independently
[rust-lightning] / lightning / src / chain / channelmonitor.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 //! The logic to monitor for on-chain transactions and create the relevant claim responses lives
11 //! here.
12 //!
13 //! ChannelMonitor objects are generated by ChannelManager in response to relevant
14 //! messages/actions, and MUST be persisted to disk (and, preferably, remotely) before progress can
15 //! be made in responding to certain messages, see [`chain::Watch`] for more.
16 //!
17 //! Note that ChannelMonitors are an important part of the lightning trust model and a copy of the
18 //! latest ChannelMonitor must always be actively monitoring for chain updates (and no out-of-date
19 //! ChannelMonitors should do so). Thus, if you're building rust-lightning into an HSM or other
20 //! security-domain-separated system design, you should consider having multiple paths for
21 //! ChannelMonitors to get out of the HSM and onto monitoring devices.
22 //!
23 //! [`chain::Watch`]: ../trait.Watch.html
24
25 use bitcoin::blockdata::block::{Block, BlockHeader};
26 use bitcoin::blockdata::transaction::{TxOut,Transaction};
27 use bitcoin::blockdata::transaction::OutPoint as BitcoinOutPoint;
28 use bitcoin::blockdata::script::{Script, Builder};
29 use bitcoin::blockdata::opcodes;
30
31 use bitcoin::hashes::Hash;
32 use bitcoin::hashes::sha256::Hash as Sha256;
33 use bitcoin::hash_types::{Txid, BlockHash, WPubkeyHash};
34
35 use bitcoin::secp256k1::{Secp256k1,Signature};
36 use bitcoin::secp256k1::key::{SecretKey,PublicKey};
37 use bitcoin::secp256k1;
38
39 use ln::msgs::DecodeError;
40 use ln::chan_utils;
41 use ln::chan_utils::{CounterpartyCommitmentSecrets, HTLCOutputInCommitment, HTLCType, ChannelTransactionParameters, HolderCommitmentTransaction};
42 use ln::channelmanager::{HTLCSource, PaymentPreimage, PaymentHash};
43 use ln::onchaintx::{OnchainTxHandler, InputDescriptors};
44 use chain;
45 use chain::chaininterface::{BroadcasterInterface, FeeEstimator};
46 use chain::transaction::{OutPoint, TransactionData};
47 use chain::keysinterface::{SpendableOutputDescriptor, StaticPaymentOutputDescriptor, DelayedPaymentOutputDescriptor, Sign, KeysInterface};
48 use util::logger::Logger;
49 use util::ser::{Readable, ReadableArgs, MaybeReadable, Writer, Writeable, U48};
50 use util::byte_utils;
51 use util::events::Event;
52
53 use std::collections::{HashMap, HashSet, hash_map};
54 use std::{cmp, mem};
55 use std::io::Error;
56 use std::ops::Deref;
57 use std::sync::Mutex;
58
59 /// An update generated by the underlying Channel itself which contains some new information the
60 /// ChannelMonitor should be made aware of.
61 #[cfg_attr(any(test, feature = "fuzztarget", feature = "_test_utils"), derive(PartialEq))]
62 #[derive(Clone)]
63 #[must_use]
64 pub struct ChannelMonitorUpdate {
65         pub(crate) updates: Vec<ChannelMonitorUpdateStep>,
66         /// The sequence number of this update. Updates *must* be replayed in-order according to this
67         /// sequence number (and updates may panic if they are not). The update_id values are strictly
68         /// increasing and increase by one for each new update, with one exception specified below.
69         ///
70         /// This sequence number is also used to track up to which points updates which returned
71         /// ChannelMonitorUpdateErr::TemporaryFailure have been applied to all copies of a given
72         /// ChannelMonitor when ChannelManager::channel_monitor_updated is called.
73         ///
74         /// The only instance where update_id values are not strictly increasing is the case where we
75         /// allow post-force-close updates with a special update ID of [`CLOSED_CHANNEL_UPDATE_ID`]. See
76         /// its docs for more details.
77         ///
78         /// [`CLOSED_CHANNEL_UPDATE_ID`]: constant.CLOSED_CHANNEL_UPDATE_ID.html
79         pub update_id: u64,
80 }
81
82 /// If:
83 ///    (1) a channel has been force closed and
84 ///    (2) we receive a preimage from a forward link that allows us to spend an HTLC output on
85 ///        this channel's (the backward link's) broadcasted commitment transaction
86 /// then we allow the `ChannelManager` to send a `ChannelMonitorUpdate` with this update ID,
87 /// with the update providing said payment preimage. No other update types are allowed after
88 /// force-close.
89 pub const CLOSED_CHANNEL_UPDATE_ID: u64 = std::u64::MAX;
90
91 impl Writeable for ChannelMonitorUpdate {
92         fn write<W: Writer>(&self, w: &mut W) -> Result<(), ::std::io::Error> {
93                 self.update_id.write(w)?;
94                 (self.updates.len() as u64).write(w)?;
95                 for update_step in self.updates.iter() {
96                         update_step.write(w)?;
97                 }
98                 Ok(())
99         }
100 }
101 impl Readable for ChannelMonitorUpdate {
102         fn read<R: ::std::io::Read>(r: &mut R) -> Result<Self, DecodeError> {
103                 let update_id: u64 = Readable::read(r)?;
104                 let len: u64 = Readable::read(r)?;
105                 let mut updates = Vec::with_capacity(cmp::min(len as usize, MAX_ALLOC_SIZE / ::std::mem::size_of::<ChannelMonitorUpdateStep>()));
106                 for _ in 0..len {
107                         updates.push(Readable::read(r)?);
108                 }
109                 Ok(Self { update_id, updates })
110         }
111 }
112
113 /// An error enum representing a failure to persist a channel monitor update.
114 #[derive(Clone, Debug)]
115 pub enum ChannelMonitorUpdateErr {
116         /// Used to indicate a temporary failure (eg connection to a watchtower or remote backup of
117         /// our state failed, but is expected to succeed at some point in the future).
118         ///
119         /// Such a failure will "freeze" a channel, preventing us from revoking old states or
120         /// submitting new commitment transactions to the counterparty. Once the update(s) which failed
121         /// have been successfully applied, ChannelManager::channel_monitor_updated can be used to
122         /// restore the channel to an operational state.
123         ///
124         /// Note that a given ChannelManager will *never* re-generate a given ChannelMonitorUpdate. If
125         /// you return a TemporaryFailure you must ensure that it is written to disk safely before
126         /// writing out the latest ChannelManager state.
127         ///
128         /// Even when a channel has been "frozen" updates to the ChannelMonitor can continue to occur
129         /// (eg if an inbound HTLC which we forwarded was claimed upstream resulting in us attempting
130         /// to claim it on this channel) and those updates must be applied wherever they can be. At
131         /// least one such updated ChannelMonitor must be persisted otherwise PermanentFailure should
132         /// be returned to get things on-chain ASAP using only the in-memory copy. Obviously updates to
133         /// the channel which would invalidate previous ChannelMonitors are not made when a channel has
134         /// been "frozen".
135         ///
136         /// Note that even if updates made after TemporaryFailure succeed you must still call
137         /// channel_monitor_updated to ensure you have the latest monitor and re-enable normal channel
138         /// operation.
139         ///
140         /// Note that the update being processed here will not be replayed for you when you call
141         /// ChannelManager::channel_monitor_updated, so you must store the update itself along
142         /// with the persisted ChannelMonitor on your own local disk prior to returning a
143         /// TemporaryFailure. You may, of course, employ a journaling approach, storing only the
144         /// ChannelMonitorUpdate on disk without updating the monitor itself, replaying the journal at
145         /// reload-time.
146         ///
147         /// For deployments where a copy of ChannelMonitors and other local state are backed up in a
148         /// remote location (with local copies persisted immediately), it is anticipated that all
149         /// updates will return TemporaryFailure until the remote copies could be updated.
150         TemporaryFailure,
151         /// Used to indicate no further channel monitor updates will be allowed (eg we've moved on to a
152         /// different watchtower and cannot update with all watchtowers that were previously informed
153         /// of this channel).
154         ///
155         /// At reception of this error, ChannelManager will force-close the channel and return at
156         /// least a final ChannelMonitorUpdate::ChannelForceClosed which must be delivered to at
157         /// least one ChannelMonitor copy. Revocation secret MUST NOT be released and offchain channel
158         /// update must be rejected.
159         ///
160         /// This failure may also signal a failure to update the local persisted copy of one of
161         /// the channel monitor instance.
162         ///
163         /// Note that even when you fail a holder commitment transaction update, you must store the
164         /// update to ensure you can claim from it in case of a duplicate copy of this ChannelMonitor
165         /// broadcasts it (e.g distributed channel-monitor deployment)
166         ///
167         /// In case of distributed watchtowers deployment, the new version must be written to disk, as
168         /// state may have been stored but rejected due to a block forcing a commitment broadcast. This
169         /// storage is used to claim outputs of rejected state confirmed onchain by another watchtower,
170         /// lagging behind on block processing.
171         PermanentFailure,
172 }
173
174 /// General Err type for ChannelMonitor actions. Generally, this implies that the data provided is
175 /// inconsistent with the ChannelMonitor being called. eg for ChannelMonitor::update_monitor this
176 /// means you tried to update a monitor for a different channel or the ChannelMonitorUpdate was
177 /// corrupted.
178 /// Contains a developer-readable error message.
179 #[derive(Clone, Debug)]
180 pub struct MonitorUpdateError(pub &'static str);
181
182 /// An event to be processed by the ChannelManager.
183 #[derive(Clone, PartialEq)]
184 pub enum MonitorEvent {
185         /// A monitor event containing an HTLCUpdate.
186         HTLCEvent(HTLCUpdate),
187
188         /// A monitor event that the Channel's commitment transaction was broadcasted.
189         CommitmentTxBroadcasted(OutPoint),
190 }
191
192 /// Simple structure sent back by `chain::Watch` when an HTLC from a forward channel is detected on
193 /// chain. Used to update the corresponding HTLC in the backward channel. Failing to pass the
194 /// preimage claim backward will lead to loss of funds.
195 ///
196 /// [`chain::Watch`]: ../trait.Watch.html
197 #[derive(Clone, PartialEq)]
198 pub struct HTLCUpdate {
199         pub(crate) payment_hash: PaymentHash,
200         pub(crate) payment_preimage: Option<PaymentPreimage>,
201         pub(crate) source: HTLCSource
202 }
203 impl_writeable!(HTLCUpdate, 0, { payment_hash, payment_preimage, source });
204
205 /// If an HTLC expires within this many blocks, don't try to claim it in a shared transaction,
206 /// instead claiming it in its own individual transaction.
207 pub(crate) const CLTV_SHARED_CLAIM_BUFFER: u32 = 12;
208 /// If an HTLC expires within this many blocks, force-close the channel to broadcast the
209 /// HTLC-Success transaction.
210 /// In other words, this is an upper bound on how many blocks we think it can take us to get a
211 /// transaction confirmed (and we use it in a few more, equivalent, places).
212 pub(crate) const CLTV_CLAIM_BUFFER: u32 = 6;
213 /// Number of blocks by which point we expect our counterparty to have seen new blocks on the
214 /// network and done a full update_fail_htlc/commitment_signed dance (+ we've updated all our
215 /// copies of ChannelMonitors, including watchtowers). We could enforce the contract by failing
216 /// at CLTV expiration height but giving a grace period to our peer may be profitable for us if he
217 /// can provide an over-late preimage. Nevertheless, grace period has to be accounted in our
218 /// CLTV_EXPIRY_DELTA to be secure. Following this policy we may decrease the rate of channel failures
219 /// due to expiration but increase the cost of funds being locked longuer in case of failure.
220 /// This delay also cover a low-power peer being slow to process blocks and so being behind us on
221 /// accurate block height.
222 /// In case of onchain failure to be pass backward we may see the last block of ANTI_REORG_DELAY
223 /// with at worst this delay, so we are not only using this value as a mercy for them but also
224 /// us as a safeguard to delay with enough time.
225 pub(crate) const LATENCY_GRACE_PERIOD_BLOCKS: u32 = 3;
226 /// Number of blocks we wait on seeing a HTLC output being solved before we fail corresponding inbound
227 /// HTLCs. This prevents us from failing backwards and then getting a reorg resulting in us losing money.
228 /// We use also this delay to be sure we can remove our in-flight claim txn from bump candidates buffer.
229 /// It may cause spurrious generation of bumped claim txn but that's allright given the outpoint is already
230 /// solved by a previous claim tx. What we want to avoid is reorg evicting our claim tx and us not
231 /// keeping bumping another claim tx to solve the outpoint.
232 pub(crate) const ANTI_REORG_DELAY: u32 = 6;
233 /// Number of blocks before confirmation at which we fail back an un-relayed HTLC or at which we
234 /// refuse to accept a new HTLC.
235 ///
236 /// This is used for a few separate purposes:
237 /// 1) if we've received an MPP HTLC to us and it expires within this many blocks and we are
238 ///    waiting on additional parts (or waiting on the preimage for any HTLC from the user), we will
239 ///    fail this HTLC,
240 /// 2) if we receive an HTLC within this many blocks of its expiry (plus one to avoid a race
241 ///    condition with the above), we will fail this HTLC without telling the user we received it,
242 /// 3) if we are waiting on a connection or a channel state update to send an HTLC to a peer, and
243 ///    that HTLC expires within this many blocks, we will simply fail the HTLC instead.
244 ///
245 /// (1) is all about protecting us - we need enough time to update the channel state before we hit
246 /// CLTV_CLAIM_BUFFER, at which point we'd go on chain to claim the HTLC with the preimage.
247 ///
248 /// (2) is the same, but with an additional buffer to avoid accepting an HTLC which is immediately
249 /// in a race condition between the user connecting a block (which would fail it) and the user
250 /// providing us the preimage (which would claim it).
251 ///
252 /// (3) is about our counterparty - we don't want to relay an HTLC to a counterparty when they may
253 /// end up force-closing the channel on us to claim it.
254 pub(crate) const HTLC_FAIL_BACK_BUFFER: u32 = CLTV_CLAIM_BUFFER + LATENCY_GRACE_PERIOD_BLOCKS;
255
256 // TODO(devrandom) replace this with HolderCommitmentTransaction
257 #[derive(Clone, PartialEq)]
258 struct HolderSignedTx {
259         /// txid of the transaction in tx, just used to make comparison faster
260         txid: Txid,
261         revocation_key: PublicKey,
262         a_htlc_key: PublicKey,
263         b_htlc_key: PublicKey,
264         delayed_payment_key: PublicKey,
265         per_commitment_point: PublicKey,
266         feerate_per_kw: u32,
267         htlc_outputs: Vec<(HTLCOutputInCommitment, Option<Signature>, Option<HTLCSource>)>,
268 }
269
270 /// We use this to track counterparty commitment transactions and htlcs outputs and
271 /// use it to generate any justice or 2nd-stage preimage/timeout transactions.
272 #[derive(PartialEq)]
273 struct CounterpartyCommitmentTransaction {
274         counterparty_delayed_payment_base_key: PublicKey,
275         counterparty_htlc_base_key: PublicKey,
276         on_counterparty_tx_csv: u16,
277         per_htlc: HashMap<Txid, Vec<HTLCOutputInCommitment>>
278 }
279
280 impl Writeable for CounterpartyCommitmentTransaction {
281         fn write<W: Writer>(&self, w: &mut W) -> Result<(), ::std::io::Error> {
282                 self.counterparty_delayed_payment_base_key.write(w)?;
283                 self.counterparty_htlc_base_key.write(w)?;
284                 w.write_all(&byte_utils::be16_to_array(self.on_counterparty_tx_csv))?;
285                 w.write_all(&byte_utils::be64_to_array(self.per_htlc.len() as u64))?;
286                 for (ref txid, ref htlcs) in self.per_htlc.iter() {
287                         w.write_all(&txid[..])?;
288                         w.write_all(&byte_utils::be64_to_array(htlcs.len() as u64))?;
289                         for &ref htlc in htlcs.iter() {
290                                 htlc.write(w)?;
291                         }
292                 }
293                 Ok(())
294         }
295 }
296 impl Readable for CounterpartyCommitmentTransaction {
297         fn read<R: ::std::io::Read>(r: &mut R) -> Result<Self, DecodeError> {
298                 let counterparty_commitment_transaction = {
299                         let counterparty_delayed_payment_base_key = Readable::read(r)?;
300                         let counterparty_htlc_base_key = Readable::read(r)?;
301                         let on_counterparty_tx_csv: u16 = Readable::read(r)?;
302                         let per_htlc_len: u64 = Readable::read(r)?;
303                         let mut per_htlc = HashMap::with_capacity(cmp::min(per_htlc_len as usize, MAX_ALLOC_SIZE / 64));
304                         for _  in 0..per_htlc_len {
305                                 let txid: Txid = Readable::read(r)?;
306                                 let htlcs_count: u64 = Readable::read(r)?;
307                                 let mut htlcs = Vec::with_capacity(cmp::min(htlcs_count as usize, MAX_ALLOC_SIZE / 32));
308                                 for _ in 0..htlcs_count {
309                                         let htlc = Readable::read(r)?;
310                                         htlcs.push(htlc);
311                                 }
312                                 if let Some(_) = per_htlc.insert(txid, htlcs) {
313                                         return Err(DecodeError::InvalidValue);
314                                 }
315                         }
316                         CounterpartyCommitmentTransaction {
317                                 counterparty_delayed_payment_base_key,
318                                 counterparty_htlc_base_key,
319                                 on_counterparty_tx_csv,
320                                 per_htlc,
321                         }
322                 };
323                 Ok(counterparty_commitment_transaction)
324         }
325 }
326
327 /// When ChannelMonitor discovers an onchain outpoint being a step of a channel and that it needs
328 /// to generate a tx to push channel state forward, we cache outpoint-solving tx material to build
329 /// a new bumped one in case of lenghty confirmation delay
330 #[derive(Clone, PartialEq)]
331 pub(crate) enum InputMaterial {
332         Revoked {
333                 per_commitment_point: PublicKey,
334                 counterparty_delayed_payment_base_key: PublicKey,
335                 counterparty_htlc_base_key: PublicKey,
336                 per_commitment_key: SecretKey,
337                 input_descriptor: InputDescriptors,
338                 amount: u64,
339                 htlc: Option<HTLCOutputInCommitment>,
340                 on_counterparty_tx_csv: u16,
341         },
342         CounterpartyHTLC {
343                 per_commitment_point: PublicKey,
344                 counterparty_delayed_payment_base_key: PublicKey,
345                 counterparty_htlc_base_key: PublicKey,
346                 preimage: Option<PaymentPreimage>,
347                 htlc: HTLCOutputInCommitment
348         },
349         HolderHTLC {
350                 preimage: Option<PaymentPreimage>,
351                 amount: u64,
352         },
353         Funding {
354                 funding_redeemscript: Script,
355         }
356 }
357
358 impl Writeable for InputMaterial  {
359         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
360                 match self {
361                         &InputMaterial::Revoked { ref per_commitment_point, ref counterparty_delayed_payment_base_key, ref counterparty_htlc_base_key, ref per_commitment_key, ref input_descriptor, ref amount, ref htlc, ref on_counterparty_tx_csv} => {
362                                 writer.write_all(&[0; 1])?;
363                                 per_commitment_point.write(writer)?;
364                                 counterparty_delayed_payment_base_key.write(writer)?;
365                                 counterparty_htlc_base_key.write(writer)?;
366                                 writer.write_all(&per_commitment_key[..])?;
367                                 input_descriptor.write(writer)?;
368                                 writer.write_all(&byte_utils::be64_to_array(*amount))?;
369                                 htlc.write(writer)?;
370                                 on_counterparty_tx_csv.write(writer)?;
371                         },
372                         &InputMaterial::CounterpartyHTLC { ref per_commitment_point, ref counterparty_delayed_payment_base_key, ref counterparty_htlc_base_key, ref preimage, ref htlc} => {
373                                 writer.write_all(&[1; 1])?;
374                                 per_commitment_point.write(writer)?;
375                                 counterparty_delayed_payment_base_key.write(writer)?;
376                                 counterparty_htlc_base_key.write(writer)?;
377                                 preimage.write(writer)?;
378                                 htlc.write(writer)?;
379                         },
380                         &InputMaterial::HolderHTLC { ref preimage, ref amount } => {
381                                 writer.write_all(&[2; 1])?;
382                                 preimage.write(writer)?;
383                                 writer.write_all(&byte_utils::be64_to_array(*amount))?;
384                         },
385                         &InputMaterial::Funding { ref funding_redeemscript } => {
386                                 writer.write_all(&[3; 1])?;
387                                 funding_redeemscript.write(writer)?;
388                         }
389                 }
390                 Ok(())
391         }
392 }
393
394 impl Readable for InputMaterial {
395         fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
396                 let input_material = match <u8 as Readable>::read(reader)? {
397                         0 => {
398                                 let per_commitment_point = Readable::read(reader)?;
399                                 let counterparty_delayed_payment_base_key = Readable::read(reader)?;
400                                 let counterparty_htlc_base_key = Readable::read(reader)?;
401                                 let per_commitment_key = Readable::read(reader)?;
402                                 let input_descriptor = Readable::read(reader)?;
403                                 let amount = Readable::read(reader)?;
404                                 let htlc = Readable::read(reader)?;
405                                 let on_counterparty_tx_csv = Readable::read(reader)?;
406                                 InputMaterial::Revoked {
407                                         per_commitment_point,
408                                         counterparty_delayed_payment_base_key,
409                                         counterparty_htlc_base_key,
410                                         per_commitment_key,
411                                         input_descriptor,
412                                         amount,
413                                         htlc,
414                                         on_counterparty_tx_csv
415                                 }
416                         },
417                         1 => {
418                                 let per_commitment_point = Readable::read(reader)?;
419                                 let counterparty_delayed_payment_base_key = Readable::read(reader)?;
420                                 let counterparty_htlc_base_key = Readable::read(reader)?;
421                                 let preimage = Readable::read(reader)?;
422                                 let htlc = Readable::read(reader)?;
423                                 InputMaterial::CounterpartyHTLC {
424                                         per_commitment_point,
425                                         counterparty_delayed_payment_base_key,
426                                         counterparty_htlc_base_key,
427                                         preimage,
428                                         htlc
429                                 }
430                         },
431                         2 => {
432                                 let preimage = Readable::read(reader)?;
433                                 let amount = Readable::read(reader)?;
434                                 InputMaterial::HolderHTLC {
435                                         preimage,
436                                         amount,
437                                 }
438                         },
439                         3 => {
440                                 InputMaterial::Funding {
441                                         funding_redeemscript: Readable::read(reader)?,
442                                 }
443                         }
444                         _ => return Err(DecodeError::InvalidValue),
445                 };
446                 Ok(input_material)
447         }
448 }
449
450 /// ClaimRequest is a descriptor structure to communicate between detection
451 /// and reaction module. They are generated by ChannelMonitor while parsing
452 /// onchain txn leaked from a channel and handed over to OnchainTxHandler which
453 /// is responsible for opportunistic aggregation, selecting and enforcing
454 /// bumping logic, building and signing transactions.
455 pub(crate) struct ClaimRequest {
456         // Block height before which claiming is exclusive to one party,
457         // after reaching it, claiming may be contentious.
458         pub(crate) absolute_timelock: u32,
459         // Timeout tx must have nLocktime set which means aggregating multiple
460         // ones must take the higher nLocktime among them to satisfy all of them.
461         // Sadly it has few pitfalls, a) it takes longuer to get fund back b) CLTV_DELTA
462         // of a sooner-HTLC could be swallowed by the highest nLocktime of the HTLC set.
463         // Do simplify we mark them as non-aggregable.
464         pub(crate) aggregable: bool,
465         // Basic bitcoin outpoint (txid, vout)
466         pub(crate) outpoint: BitcoinOutPoint,
467         // Following outpoint type, set of data needed to generate transaction digest
468         // and satisfy witness program.
469         pub(crate) witness_data: InputMaterial
470 }
471
472 /// Upon discovering of some classes of onchain tx by ChannelMonitor, we may have to take actions on it
473 /// once they mature to enough confirmations (ANTI_REORG_DELAY)
474 #[derive(Clone, PartialEq)]
475 enum OnchainEvent {
476         /// HTLC output getting solved by a timeout, at maturation we pass upstream payment source information to solve
477         /// inbound HTLC in backward channel. Note, in case of preimage, we pass info to upstream without delay as we can
478         /// only win from it, so it's never an OnchainEvent
479         HTLCUpdate {
480                 htlc_update: (HTLCSource, PaymentHash),
481         },
482         MaturingOutput {
483                 descriptor: SpendableOutputDescriptor,
484         },
485 }
486
487 const SERIALIZATION_VERSION: u8 = 1;
488 const MIN_SERIALIZATION_VERSION: u8 = 1;
489
490 #[cfg_attr(any(test, feature = "fuzztarget", feature = "_test_utils"), derive(PartialEq))]
491 #[derive(Clone)]
492 pub(crate) enum ChannelMonitorUpdateStep {
493         LatestHolderCommitmentTXInfo {
494                 commitment_tx: HolderCommitmentTransaction,
495                 htlc_outputs: Vec<(HTLCOutputInCommitment, Option<Signature>, Option<HTLCSource>)>,
496         },
497         LatestCounterpartyCommitmentTXInfo {
498                 commitment_txid: Txid,
499                 htlc_outputs: Vec<(HTLCOutputInCommitment, Option<Box<HTLCSource>>)>,
500                 commitment_number: u64,
501                 their_revocation_point: PublicKey,
502         },
503         PaymentPreimage {
504                 payment_preimage: PaymentPreimage,
505         },
506         CommitmentSecret {
507                 idx: u64,
508                 secret: [u8; 32],
509         },
510         /// Used to indicate that the no future updates will occur, and likely that the latest holder
511         /// commitment transaction(s) should be broadcast, as the channel has been force-closed.
512         ChannelForceClosed {
513                 /// If set to false, we shouldn't broadcast the latest holder commitment transaction as we
514                 /// think we've fallen behind!
515                 should_broadcast: bool,
516         },
517 }
518
519 impl Writeable for ChannelMonitorUpdateStep {
520         fn write<W: Writer>(&self, w: &mut W) -> Result<(), ::std::io::Error> {
521                 match self {
522                         &ChannelMonitorUpdateStep::LatestHolderCommitmentTXInfo { ref commitment_tx, ref htlc_outputs } => {
523                                 0u8.write(w)?;
524                                 commitment_tx.write(w)?;
525                                 (htlc_outputs.len() as u64).write(w)?;
526                                 for &(ref output, ref signature, ref source) in htlc_outputs.iter() {
527                                         output.write(w)?;
528                                         signature.write(w)?;
529                                         source.write(w)?;
530                                 }
531                         }
532                         &ChannelMonitorUpdateStep::LatestCounterpartyCommitmentTXInfo { commitment_txid, ref htlc_outputs, ref commitment_number, ref their_revocation_point } => {
533                                 1u8.write(w)?;
534                                 commitment_txid.write(w)?;
535                                 commitment_number.write(w)?;
536                                 their_revocation_point.write(w)?;
537                                 (htlc_outputs.len() as u64).write(w)?;
538                                 for &(ref output, ref source) in htlc_outputs.iter() {
539                                         output.write(w)?;
540                                         source.as_ref().map(|b| b.as_ref()).write(w)?;
541                                 }
542                         },
543                         &ChannelMonitorUpdateStep::PaymentPreimage { ref payment_preimage } => {
544                                 2u8.write(w)?;
545                                 payment_preimage.write(w)?;
546                         },
547                         &ChannelMonitorUpdateStep::CommitmentSecret { ref idx, ref secret } => {
548                                 3u8.write(w)?;
549                                 idx.write(w)?;
550                                 secret.write(w)?;
551                         },
552                         &ChannelMonitorUpdateStep::ChannelForceClosed { ref should_broadcast } => {
553                                 4u8.write(w)?;
554                                 should_broadcast.write(w)?;
555                         },
556                 }
557                 Ok(())
558         }
559 }
560 impl Readable for ChannelMonitorUpdateStep {
561         fn read<R: ::std::io::Read>(r: &mut R) -> Result<Self, DecodeError> {
562                 match Readable::read(r)? {
563                         0u8 => {
564                                 Ok(ChannelMonitorUpdateStep::LatestHolderCommitmentTXInfo {
565                                         commitment_tx: Readable::read(r)?,
566                                         htlc_outputs: {
567                                                 let len: u64 = Readable::read(r)?;
568                                                 let mut res = Vec::new();
569                                                 for _ in 0..len {
570                                                         res.push((Readable::read(r)?, Readable::read(r)?, Readable::read(r)?));
571                                                 }
572                                                 res
573                                         },
574                                 })
575                         },
576                         1u8 => {
577                                 Ok(ChannelMonitorUpdateStep::LatestCounterpartyCommitmentTXInfo {
578                                         commitment_txid: Readable::read(r)?,
579                                         commitment_number: Readable::read(r)?,
580                                         their_revocation_point: Readable::read(r)?,
581                                         htlc_outputs: {
582                                                 let len: u64 = Readable::read(r)?;
583                                                 let mut res = Vec::new();
584                                                 for _ in 0..len {
585                                                         res.push((Readable::read(r)?, <Option<HTLCSource> as Readable>::read(r)?.map(|o| Box::new(o))));
586                                                 }
587                                                 res
588                                         },
589                                 })
590                         },
591                         2u8 => {
592                                 Ok(ChannelMonitorUpdateStep::PaymentPreimage {
593                                         payment_preimage: Readable::read(r)?,
594                                 })
595                         },
596                         3u8 => {
597                                 Ok(ChannelMonitorUpdateStep::CommitmentSecret {
598                                         idx: Readable::read(r)?,
599                                         secret: Readable::read(r)?,
600                                 })
601                         },
602                         4u8 => {
603                                 Ok(ChannelMonitorUpdateStep::ChannelForceClosed {
604                                         should_broadcast: Readable::read(r)?
605                                 })
606                         },
607                         _ => Err(DecodeError::InvalidValue),
608                 }
609         }
610 }
611
612 /// A ChannelMonitor handles chain events (blocks connected and disconnected) and generates
613 /// on-chain transactions to ensure no loss of funds occurs.
614 ///
615 /// You MUST ensure that no ChannelMonitors for a given channel anywhere contain out-of-date
616 /// information and are actively monitoring the chain.
617 ///
618 /// Pending Events or updated HTLCs which have not yet been read out by
619 /// get_and_clear_pending_monitor_events or get_and_clear_pending_events are serialized to disk and
620 /// reloaded at deserialize-time. Thus, you must ensure that, when handling events, all events
621 /// gotten are fully handled before re-serializing the new state.
622 ///
623 /// Note that the deserializer is only implemented for (BlockHash, ChannelMonitor), which
624 /// tells you the last block hash which was block_connect()ed. You MUST rescan any blocks along
625 /// the "reorg path" (ie disconnecting blocks until you find a common ancestor from both the
626 /// returned block hash and the the current chain and then reconnecting blocks to get to the
627 /// best chain) upon deserializing the object!
628 pub struct ChannelMonitor<Signer: Sign> {
629         #[cfg(test)]
630         pub(crate) inner: Mutex<ChannelMonitorImpl<Signer>>,
631         #[cfg(not(test))]
632         inner: Mutex<ChannelMonitorImpl<Signer>>,
633 }
634
635 pub(crate) struct ChannelMonitorImpl<Signer: Sign> {
636         latest_update_id: u64,
637         commitment_transaction_number_obscure_factor: u64,
638
639         destination_script: Script,
640         broadcasted_holder_revokable_script: Option<(Script, PublicKey, PublicKey)>,
641         counterparty_payment_script: Script,
642         shutdown_script: Script,
643
644         channel_keys_id: [u8; 32],
645         holder_revocation_basepoint: PublicKey,
646         funding_info: (OutPoint, Script),
647         current_counterparty_commitment_txid: Option<Txid>,
648         prev_counterparty_commitment_txid: Option<Txid>,
649
650         counterparty_tx_cache: CounterpartyCommitmentTransaction,
651         funding_redeemscript: Script,
652         channel_value_satoshis: u64,
653         // first is the idx of the first of the two revocation points
654         their_cur_revocation_points: Option<(u64, PublicKey, Option<PublicKey>)>,
655
656         on_holder_tx_csv: u16,
657
658         commitment_secrets: CounterpartyCommitmentSecrets,
659         counterparty_claimable_outpoints: HashMap<Txid, Vec<(HTLCOutputInCommitment, Option<Box<HTLCSource>>)>>,
660         /// We cannot identify HTLC-Success or HTLC-Timeout transactions by themselves on the chain.
661         /// Nor can we figure out their commitment numbers without the commitment transaction they are
662         /// spending. Thus, in order to claim them via revocation key, we track all the counterparty
663         /// commitment transactions which we find on-chain, mapping them to the commitment number which
664         /// can be used to derive the revocation key and claim the transactions.
665         counterparty_commitment_txn_on_chain: HashMap<Txid, u64>,
666         /// Cache used to make pruning of payment_preimages faster.
667         /// Maps payment_hash values to commitment numbers for counterparty transactions for non-revoked
668         /// counterparty transactions (ie should remain pretty small).
669         /// Serialized to disk but should generally not be sent to Watchtowers.
670         counterparty_hash_commitment_number: HashMap<PaymentHash, u64>,
671
672         // We store two holder commitment transactions to avoid any race conditions where we may update
673         // some monitors (potentially on watchtowers) but then fail to update others, resulting in the
674         // various monitors for one channel being out of sync, and us broadcasting a holder
675         // transaction for which we have deleted claim information on some watchtowers.
676         prev_holder_signed_commitment_tx: Option<HolderSignedTx>,
677         current_holder_commitment_tx: HolderSignedTx,
678
679         // Used just for ChannelManager to make sure it has the latest channel data during
680         // deserialization
681         current_counterparty_commitment_number: u64,
682         // Used just for ChannelManager to make sure it has the latest channel data during
683         // deserialization
684         current_holder_commitment_number: u64,
685
686         payment_preimages: HashMap<PaymentHash, PaymentPreimage>,
687
688         pending_monitor_events: Vec<MonitorEvent>,
689         pending_events: Vec<Event>,
690
691         // Used to track onchain events, i.e transactions parts of channels confirmed on chain, on which
692         // we have to take actions once they reach enough confs. Key is a block height timer, i.e we enforce
693         // actions when we receive a block with given height. Actions depend on OnchainEvent type.
694         onchain_events_waiting_threshold_conf: HashMap<u32, Vec<OnchainEvent>>,
695
696         // If we get serialized out and re-read, we need to make sure that the chain monitoring
697         // interface knows about the TXOs that we want to be notified of spends of. We could probably
698         // be smart and derive them from the above storage fields, but its much simpler and more
699         // Obviously Correct (tm) if we just keep track of them explicitly.
700         outputs_to_watch: HashMap<Txid, Vec<(u32, Script)>>,
701
702         #[cfg(test)]
703         pub onchain_tx_handler: OnchainTxHandler<Signer>,
704         #[cfg(not(test))]
705         onchain_tx_handler: OnchainTxHandler<Signer>,
706
707         // This is set when the Channel[Manager] generated a ChannelMonitorUpdate which indicated the
708         // channel has been force-closed. After this is set, no further holder commitment transaction
709         // updates may occur, and we panic!() if one is provided.
710         lockdown_from_offchain: bool,
711
712         // Set once we've signed a holder commitment transaction and handed it over to our
713         // OnchainTxHandler. After this is set, no future updates to our holder commitment transactions
714         // may occur, and we fail any such monitor updates.
715         //
716         // In case of update rejection due to a locally already signed commitment transaction, we
717         // nevertheless store update content to track in case of concurrent broadcast by another
718         // remote monitor out-of-order with regards to the block view.
719         holder_tx_signed: bool,
720
721         // We simply modify last_block_hash in Channel's block_connected so that serialization is
722         // consistent but hopefully the users' copy handles block_connected in a consistent way.
723         // (we do *not*, however, update them in update_monitor to ensure any local user copies keep
724         // their last_block_hash from its state and not based on updated copies that didn't run through
725         // the full block_connected).
726         last_block_hash: BlockHash,
727         secp_ctx: Secp256k1<secp256k1::All>, //TODO: dedup this a bit...
728 }
729
730 #[cfg(any(test, feature = "fuzztarget", feature = "_test_utils"))]
731 /// Used only in testing and fuzztarget to check serialization roundtrips don't change the
732 /// underlying object
733 impl<Signer: Sign> PartialEq for ChannelMonitor<Signer> {
734         fn eq(&self, other: &Self) -> bool {
735                 let inner = self.inner.lock().unwrap();
736                 let other = other.inner.lock().unwrap();
737                 inner.eq(&other)
738         }
739 }
740
741 #[cfg(any(test, feature = "fuzztarget", feature = "_test_utils"))]
742 /// Used only in testing and fuzztarget to check serialization roundtrips don't change the
743 /// underlying object
744 impl<Signer: Sign> PartialEq for ChannelMonitorImpl<Signer> {
745         fn eq(&self, other: &Self) -> bool {
746                 if self.latest_update_id != other.latest_update_id ||
747                         self.commitment_transaction_number_obscure_factor != other.commitment_transaction_number_obscure_factor ||
748                         self.destination_script != other.destination_script ||
749                         self.broadcasted_holder_revokable_script != other.broadcasted_holder_revokable_script ||
750                         self.counterparty_payment_script != other.counterparty_payment_script ||
751                         self.channel_keys_id != other.channel_keys_id ||
752                         self.holder_revocation_basepoint != other.holder_revocation_basepoint ||
753                         self.funding_info != other.funding_info ||
754                         self.current_counterparty_commitment_txid != other.current_counterparty_commitment_txid ||
755                         self.prev_counterparty_commitment_txid != other.prev_counterparty_commitment_txid ||
756                         self.counterparty_tx_cache != other.counterparty_tx_cache ||
757                         self.funding_redeemscript != other.funding_redeemscript ||
758                         self.channel_value_satoshis != other.channel_value_satoshis ||
759                         self.their_cur_revocation_points != other.their_cur_revocation_points ||
760                         self.on_holder_tx_csv != other.on_holder_tx_csv ||
761                         self.commitment_secrets != other.commitment_secrets ||
762                         self.counterparty_claimable_outpoints != other.counterparty_claimable_outpoints ||
763                         self.counterparty_commitment_txn_on_chain != other.counterparty_commitment_txn_on_chain ||
764                         self.counterparty_hash_commitment_number != other.counterparty_hash_commitment_number ||
765                         self.prev_holder_signed_commitment_tx != other.prev_holder_signed_commitment_tx ||
766                         self.current_counterparty_commitment_number != other.current_counterparty_commitment_number ||
767                         self.current_holder_commitment_number != other.current_holder_commitment_number ||
768                         self.current_holder_commitment_tx != other.current_holder_commitment_tx ||
769                         self.payment_preimages != other.payment_preimages ||
770                         self.pending_monitor_events != other.pending_monitor_events ||
771                         self.pending_events.len() != other.pending_events.len() || // We trust events to round-trip properly
772                         self.onchain_events_waiting_threshold_conf != other.onchain_events_waiting_threshold_conf ||
773                         self.outputs_to_watch != other.outputs_to_watch ||
774                         self.lockdown_from_offchain != other.lockdown_from_offchain ||
775                         self.holder_tx_signed != other.holder_tx_signed
776                 {
777                         false
778                 } else {
779                         true
780                 }
781         }
782 }
783
784 impl<Signer: Sign> Writeable for ChannelMonitor<Signer> {
785         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
786                 //TODO: We still write out all the serialization here manually instead of using the fancy
787                 //serialization framework we have, we should migrate things over to it.
788                 writer.write_all(&[SERIALIZATION_VERSION; 1])?;
789                 writer.write_all(&[MIN_SERIALIZATION_VERSION; 1])?;
790
791                 self.inner.lock().unwrap().write(writer)
792         }
793 }
794
795 impl<Signer: Sign> Writeable for ChannelMonitorImpl<Signer> {
796         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
797                 self.latest_update_id.write(writer)?;
798
799                 // Set in initial Channel-object creation, so should always be set by now:
800                 U48(self.commitment_transaction_number_obscure_factor).write(writer)?;
801
802                 self.destination_script.write(writer)?;
803                 if let Some(ref broadcasted_holder_revokable_script) = self.broadcasted_holder_revokable_script {
804                         writer.write_all(&[0; 1])?;
805                         broadcasted_holder_revokable_script.0.write(writer)?;
806                         broadcasted_holder_revokable_script.1.write(writer)?;
807                         broadcasted_holder_revokable_script.2.write(writer)?;
808                 } else {
809                         writer.write_all(&[1; 1])?;
810                 }
811
812                 self.counterparty_payment_script.write(writer)?;
813                 self.shutdown_script.write(writer)?;
814
815                 self.channel_keys_id.write(writer)?;
816                 self.holder_revocation_basepoint.write(writer)?;
817                 writer.write_all(&self.funding_info.0.txid[..])?;
818                 writer.write_all(&byte_utils::be16_to_array(self.funding_info.0.index))?;
819                 self.funding_info.1.write(writer)?;
820                 self.current_counterparty_commitment_txid.write(writer)?;
821                 self.prev_counterparty_commitment_txid.write(writer)?;
822
823                 self.counterparty_tx_cache.write(writer)?;
824                 self.funding_redeemscript.write(writer)?;
825                 self.channel_value_satoshis.write(writer)?;
826
827                 match self.their_cur_revocation_points {
828                         Some((idx, pubkey, second_option)) => {
829                                 writer.write_all(&byte_utils::be48_to_array(idx))?;
830                                 writer.write_all(&pubkey.serialize())?;
831                                 match second_option {
832                                         Some(second_pubkey) => {
833                                                 writer.write_all(&second_pubkey.serialize())?;
834                                         },
835                                         None => {
836                                                 writer.write_all(&[0; 33])?;
837                                         },
838                                 }
839                         },
840                         None => {
841                                 writer.write_all(&byte_utils::be48_to_array(0))?;
842                         },
843                 }
844
845                 writer.write_all(&byte_utils::be16_to_array(self.on_holder_tx_csv))?;
846
847                 self.commitment_secrets.write(writer)?;
848
849                 macro_rules! serialize_htlc_in_commitment {
850                         ($htlc_output: expr) => {
851                                 writer.write_all(&[$htlc_output.offered as u8; 1])?;
852                                 writer.write_all(&byte_utils::be64_to_array($htlc_output.amount_msat))?;
853                                 writer.write_all(&byte_utils::be32_to_array($htlc_output.cltv_expiry))?;
854                                 writer.write_all(&$htlc_output.payment_hash.0[..])?;
855                                 $htlc_output.transaction_output_index.write(writer)?;
856                         }
857                 }
858
859                 writer.write_all(&byte_utils::be64_to_array(self.counterparty_claimable_outpoints.len() as u64))?;
860                 for (ref txid, ref htlc_infos) in self.counterparty_claimable_outpoints.iter() {
861                         writer.write_all(&txid[..])?;
862                         writer.write_all(&byte_utils::be64_to_array(htlc_infos.len() as u64))?;
863                         for &(ref htlc_output, ref htlc_source) in htlc_infos.iter() {
864                                 serialize_htlc_in_commitment!(htlc_output);
865                                 htlc_source.as_ref().map(|b| b.as_ref()).write(writer)?;
866                         }
867                 }
868
869                 writer.write_all(&byte_utils::be64_to_array(self.counterparty_commitment_txn_on_chain.len() as u64))?;
870                 for (ref txid, commitment_number) in self.counterparty_commitment_txn_on_chain.iter() {
871                         writer.write_all(&txid[..])?;
872                         writer.write_all(&byte_utils::be48_to_array(*commitment_number))?;
873                 }
874
875                 writer.write_all(&byte_utils::be64_to_array(self.counterparty_hash_commitment_number.len() as u64))?;
876                 for (ref payment_hash, commitment_number) in self.counterparty_hash_commitment_number.iter() {
877                         writer.write_all(&payment_hash.0[..])?;
878                         writer.write_all(&byte_utils::be48_to_array(*commitment_number))?;
879                 }
880
881                 macro_rules! serialize_holder_tx {
882                         ($holder_tx: expr) => {
883                                 $holder_tx.txid.write(writer)?;
884                                 writer.write_all(&$holder_tx.revocation_key.serialize())?;
885                                 writer.write_all(&$holder_tx.a_htlc_key.serialize())?;
886                                 writer.write_all(&$holder_tx.b_htlc_key.serialize())?;
887                                 writer.write_all(&$holder_tx.delayed_payment_key.serialize())?;
888                                 writer.write_all(&$holder_tx.per_commitment_point.serialize())?;
889
890                                 writer.write_all(&byte_utils::be32_to_array($holder_tx.feerate_per_kw))?;
891                                 writer.write_all(&byte_utils::be64_to_array($holder_tx.htlc_outputs.len() as u64))?;
892                                 for &(ref htlc_output, ref sig, ref htlc_source) in $holder_tx.htlc_outputs.iter() {
893                                         serialize_htlc_in_commitment!(htlc_output);
894                                         if let &Some(ref their_sig) = sig {
895                                                 1u8.write(writer)?;
896                                                 writer.write_all(&their_sig.serialize_compact())?;
897                                         } else {
898                                                 0u8.write(writer)?;
899                                         }
900                                         htlc_source.write(writer)?;
901                                 }
902                         }
903                 }
904
905                 if let Some(ref prev_holder_tx) = self.prev_holder_signed_commitment_tx {
906                         writer.write_all(&[1; 1])?;
907                         serialize_holder_tx!(prev_holder_tx);
908                 } else {
909                         writer.write_all(&[0; 1])?;
910                 }
911
912                 serialize_holder_tx!(self.current_holder_commitment_tx);
913
914                 writer.write_all(&byte_utils::be48_to_array(self.current_counterparty_commitment_number))?;
915                 writer.write_all(&byte_utils::be48_to_array(self.current_holder_commitment_number))?;
916
917                 writer.write_all(&byte_utils::be64_to_array(self.payment_preimages.len() as u64))?;
918                 for payment_preimage in self.payment_preimages.values() {
919                         writer.write_all(&payment_preimage.0[..])?;
920                 }
921
922                 writer.write_all(&byte_utils::be64_to_array(self.pending_monitor_events.len() as u64))?;
923                 for event in self.pending_monitor_events.iter() {
924                         match event {
925                                 MonitorEvent::HTLCEvent(upd) => {
926                                         0u8.write(writer)?;
927                                         upd.write(writer)?;
928                                 },
929                                 MonitorEvent::CommitmentTxBroadcasted(_) => 1u8.write(writer)?
930                         }
931                 }
932
933                 writer.write_all(&byte_utils::be64_to_array(self.pending_events.len() as u64))?;
934                 for event in self.pending_events.iter() {
935                         event.write(writer)?;
936                 }
937
938                 self.last_block_hash.write(writer)?;
939
940                 writer.write_all(&byte_utils::be64_to_array(self.onchain_events_waiting_threshold_conf.len() as u64))?;
941                 for (ref target, ref events) in self.onchain_events_waiting_threshold_conf.iter() {
942                         writer.write_all(&byte_utils::be32_to_array(**target))?;
943                         writer.write_all(&byte_utils::be64_to_array(events.len() as u64))?;
944                         for ev in events.iter() {
945                                 match *ev {
946                                         OnchainEvent::HTLCUpdate { ref htlc_update } => {
947                                                 0u8.write(writer)?;
948                                                 htlc_update.0.write(writer)?;
949                                                 htlc_update.1.write(writer)?;
950                                         },
951                                         OnchainEvent::MaturingOutput { ref descriptor } => {
952                                                 1u8.write(writer)?;
953                                                 descriptor.write(writer)?;
954                                         },
955                                 }
956                         }
957                 }
958
959                 (self.outputs_to_watch.len() as u64).write(writer)?;
960                 for (txid, idx_scripts) in self.outputs_to_watch.iter() {
961                         txid.write(writer)?;
962                         (idx_scripts.len() as u64).write(writer)?;
963                         for (idx, script) in idx_scripts.iter() {
964                                 idx.write(writer)?;
965                                 script.write(writer)?;
966                         }
967                 }
968                 self.onchain_tx_handler.write(writer)?;
969
970                 self.lockdown_from_offchain.write(writer)?;
971                 self.holder_tx_signed.write(writer)?;
972
973                 Ok(())
974         }
975 }
976
977 impl<Signer: Sign> ChannelMonitor<Signer> {
978         pub(crate) fn new(secp_ctx: Secp256k1<secp256k1::All>, keys: Signer, shutdown_pubkey: &PublicKey,
979                           on_counterparty_tx_csv: u16, destination_script: &Script, funding_info: (OutPoint, Script),
980                           channel_parameters: &ChannelTransactionParameters,
981                           funding_redeemscript: Script, channel_value_satoshis: u64,
982                           commitment_transaction_number_obscure_factor: u64,
983                           initial_holder_commitment_tx: HolderCommitmentTransaction,
984                           last_block_hash: BlockHash) -> ChannelMonitor<Signer> {
985
986                 assert!(commitment_transaction_number_obscure_factor <= (1 << 48));
987                 let our_channel_close_key_hash = WPubkeyHash::hash(&shutdown_pubkey.serialize());
988                 let shutdown_script = Builder::new().push_opcode(opcodes::all::OP_PUSHBYTES_0).push_slice(&our_channel_close_key_hash[..]).into_script();
989                 let payment_key_hash = WPubkeyHash::hash(&keys.pubkeys().payment_point.serialize());
990                 let counterparty_payment_script = Builder::new().push_opcode(opcodes::all::OP_PUSHBYTES_0).push_slice(&payment_key_hash[..]).into_script();
991
992                 let counterparty_channel_parameters = channel_parameters.counterparty_parameters.as_ref().unwrap();
993                 let counterparty_delayed_payment_base_key = counterparty_channel_parameters.pubkeys.delayed_payment_basepoint;
994                 let counterparty_htlc_base_key = counterparty_channel_parameters.pubkeys.htlc_basepoint;
995                 let counterparty_tx_cache = CounterpartyCommitmentTransaction { counterparty_delayed_payment_base_key, counterparty_htlc_base_key, on_counterparty_tx_csv, per_htlc: HashMap::new() };
996
997                 let channel_keys_id = keys.channel_keys_id();
998                 let holder_revocation_basepoint = keys.pubkeys().revocation_basepoint;
999
1000                 // block for Rust 1.34 compat
1001                 let (holder_commitment_tx, current_holder_commitment_number) = {
1002                         let trusted_tx = initial_holder_commitment_tx.trust();
1003                         let txid = trusted_tx.txid();
1004
1005                         let tx_keys = trusted_tx.keys();
1006                         let holder_commitment_tx = HolderSignedTx {
1007                                 txid,
1008                                 revocation_key: tx_keys.revocation_key,
1009                                 a_htlc_key: tx_keys.broadcaster_htlc_key,
1010                                 b_htlc_key: tx_keys.countersignatory_htlc_key,
1011                                 delayed_payment_key: tx_keys.broadcaster_delayed_payment_key,
1012                                 per_commitment_point: tx_keys.per_commitment_point,
1013                                 feerate_per_kw: trusted_tx.feerate_per_kw(),
1014                                 htlc_outputs: Vec::new(), // There are never any HTLCs in the initial commitment transactions
1015                         };
1016                         (holder_commitment_tx, trusted_tx.commitment_number())
1017                 };
1018
1019                 let onchain_tx_handler =
1020                         OnchainTxHandler::new(destination_script.clone(), keys,
1021                         channel_parameters.clone(), initial_holder_commitment_tx, secp_ctx.clone());
1022
1023                 let mut outputs_to_watch = HashMap::new();
1024                 outputs_to_watch.insert(funding_info.0.txid, vec![(funding_info.0.index as u32, funding_info.1.clone())]);
1025
1026                 ChannelMonitor {
1027                         inner: Mutex::new(ChannelMonitorImpl {
1028                                 latest_update_id: 0,
1029                                 commitment_transaction_number_obscure_factor,
1030
1031                                 destination_script: destination_script.clone(),
1032                                 broadcasted_holder_revokable_script: None,
1033                                 counterparty_payment_script,
1034                                 shutdown_script,
1035
1036                                 channel_keys_id,
1037                                 holder_revocation_basepoint,
1038                                 funding_info,
1039                                 current_counterparty_commitment_txid: None,
1040                                 prev_counterparty_commitment_txid: None,
1041
1042                                 counterparty_tx_cache,
1043                                 funding_redeemscript,
1044                                 channel_value_satoshis,
1045                                 their_cur_revocation_points: None,
1046
1047                                 on_holder_tx_csv: counterparty_channel_parameters.selected_contest_delay,
1048
1049                                 commitment_secrets: CounterpartyCommitmentSecrets::new(),
1050                                 counterparty_claimable_outpoints: HashMap::new(),
1051                                 counterparty_commitment_txn_on_chain: HashMap::new(),
1052                                 counterparty_hash_commitment_number: HashMap::new(),
1053
1054                                 prev_holder_signed_commitment_tx: None,
1055                                 current_holder_commitment_tx: holder_commitment_tx,
1056                                 current_counterparty_commitment_number: 1 << 48,
1057                                 current_holder_commitment_number,
1058
1059                                 payment_preimages: HashMap::new(),
1060                                 pending_monitor_events: Vec::new(),
1061                                 pending_events: Vec::new(),
1062
1063                                 onchain_events_waiting_threshold_conf: HashMap::new(),
1064                                 outputs_to_watch,
1065
1066                                 onchain_tx_handler,
1067
1068                                 lockdown_from_offchain: false,
1069                                 holder_tx_signed: false,
1070
1071                                 last_block_hash,
1072                                 secp_ctx,
1073                         }),
1074                 }
1075         }
1076
1077         #[cfg(test)]
1078         fn provide_secret(&self, idx: u64, secret: [u8; 32]) -> Result<(), MonitorUpdateError> {
1079                 self.inner.lock().unwrap().provide_secret(idx, secret)
1080         }
1081
1082         /// Informs this monitor of the latest counterparty (ie non-broadcastable) commitment transaction.
1083         /// The monitor watches for it to be broadcasted and then uses the HTLC information (and
1084         /// possibly future revocation/preimage information) to claim outputs where possible.
1085         /// We cache also the mapping hash:commitment number to lighten pruning of old preimages by watchtowers.
1086         pub(crate) fn provide_latest_counterparty_commitment_tx<L: Deref>(
1087                 &self,
1088                 txid: Txid,
1089                 htlc_outputs: Vec<(HTLCOutputInCommitment, Option<Box<HTLCSource>>)>,
1090                 commitment_number: u64,
1091                 their_revocation_point: PublicKey,
1092                 logger: &L,
1093         ) where L::Target: Logger {
1094                 self.inner.lock().unwrap().provide_latest_counterparty_commitment_tx(
1095                         txid, htlc_outputs, commitment_number, their_revocation_point, logger)
1096         }
1097
1098         #[cfg(test)]
1099         fn provide_latest_holder_commitment_tx(
1100                 &self,
1101                 holder_commitment_tx: HolderCommitmentTransaction,
1102                 htlc_outputs: Vec<(HTLCOutputInCommitment, Option<Signature>, Option<HTLCSource>)>,
1103         ) -> Result<(), MonitorUpdateError> {
1104                 self.inner.lock().unwrap().provide_latest_holder_commitment_tx(
1105                         holder_commitment_tx, htlc_outputs)
1106         }
1107
1108         #[cfg(test)]
1109         pub(crate) fn provide_payment_preimage<B: Deref, F: Deref, L: Deref>(
1110                 &self,
1111                 payment_hash: &PaymentHash,
1112                 payment_preimage: &PaymentPreimage,
1113                 broadcaster: &B,
1114                 fee_estimator: &F,
1115                 logger: &L,
1116         ) where
1117                 B::Target: BroadcasterInterface,
1118                 F::Target: FeeEstimator,
1119                 L::Target: Logger,
1120         {
1121                 self.inner.lock().unwrap().provide_payment_preimage(
1122                         payment_hash, payment_preimage, broadcaster, fee_estimator, logger)
1123         }
1124
1125         pub(crate) fn broadcast_latest_holder_commitment_txn<B: Deref, L: Deref>(
1126                 &self,
1127                 broadcaster: &B,
1128                 logger: &L,
1129         ) where
1130                 B::Target: BroadcasterInterface,
1131                 L::Target: Logger,
1132         {
1133                 self.inner.lock().unwrap().broadcast_latest_holder_commitment_txn(broadcaster, logger)
1134         }
1135
1136         /// Updates a ChannelMonitor on the basis of some new information provided by the Channel
1137         /// itself.
1138         ///
1139         /// panics if the given update is not the next update by update_id.
1140         pub fn update_monitor<B: Deref, F: Deref, L: Deref>(
1141                 &self,
1142                 updates: &ChannelMonitorUpdate,
1143                 broadcaster: &B,
1144                 fee_estimator: &F,
1145                 logger: &L,
1146         ) -> Result<(), MonitorUpdateError>
1147         where
1148                 B::Target: BroadcasterInterface,
1149                 F::Target: FeeEstimator,
1150                 L::Target: Logger,
1151         {
1152                 self.inner.lock().unwrap().update_monitor(updates, broadcaster, fee_estimator, logger)
1153         }
1154
1155         /// Gets the update_id from the latest ChannelMonitorUpdate which was applied to this
1156         /// ChannelMonitor.
1157         pub fn get_latest_update_id(&self) -> u64 {
1158                 self.inner.lock().unwrap().get_latest_update_id()
1159         }
1160
1161         /// Gets the funding transaction outpoint of the channel this ChannelMonitor is monitoring for.
1162         pub fn get_funding_txo(&self) -> (OutPoint, Script) {
1163                 self.inner.lock().unwrap().get_funding_txo().clone()
1164         }
1165
1166         /// Gets a list of txids, with their output scripts (in the order they appear in the
1167         /// transaction), which we must learn about spends of via block_connected().
1168         ///
1169         /// (C-not exported) because we have no HashMap bindings
1170         pub fn get_outputs_to_watch(&self) -> HashMap<Txid, Vec<(u32, Script)>> {
1171                 self.inner.lock().unwrap().get_outputs_to_watch().clone()
1172         }
1173
1174         /// Get the list of HTLCs who's status has been updated on chain. This should be called by
1175         /// ChannelManager via [`chain::Watch::release_pending_monitor_events`].
1176         ///
1177         /// [`chain::Watch::release_pending_monitor_events`]: ../trait.Watch.html#tymethod.release_pending_monitor_events
1178         pub fn get_and_clear_pending_monitor_events(&self) -> Vec<MonitorEvent> {
1179                 self.inner.lock().unwrap().get_and_clear_pending_monitor_events()
1180         }
1181
1182         /// Gets the list of pending events which were generated by previous actions, clearing the list
1183         /// in the process.
1184         ///
1185         /// This is called by ChainMonitor::get_and_clear_pending_events() and is equivalent to
1186         /// EventsProvider::get_and_clear_pending_events() except that it requires &mut self as we do
1187         /// no internal locking in ChannelMonitors.
1188         pub fn get_and_clear_pending_events(&self) -> Vec<Event> {
1189                 self.inner.lock().unwrap().get_and_clear_pending_events()
1190         }
1191
1192         pub(crate) fn get_min_seen_secret(&self) -> u64 {
1193                 self.inner.lock().unwrap().get_min_seen_secret()
1194         }
1195
1196         pub(crate) fn get_cur_counterparty_commitment_number(&self) -> u64 {
1197                 self.inner.lock().unwrap().get_cur_counterparty_commitment_number()
1198         }
1199
1200         pub(crate) fn get_cur_holder_commitment_number(&self) -> u64 {
1201                 self.inner.lock().unwrap().get_cur_holder_commitment_number()
1202         }
1203
1204         /// Used by ChannelManager deserialization to broadcast the latest holder state if its copy of
1205         /// the Channel was out-of-date. You may use it to get a broadcastable holder toxic tx in case of
1206         /// fallen-behind, i.e when receiving a channel_reestablish with a proof that our counterparty side knows
1207         /// a higher revocation secret than the holder commitment number we are aware of. Broadcasting these
1208         /// transactions are UNSAFE, as they allow counterparty side to punish you. Nevertheless you may want to
1209         /// broadcast them if counterparty don't close channel with his higher commitment transaction after a
1210         /// substantial amount of time (a month or even a year) to get back funds. Best may be to contact
1211         /// out-of-band the other node operator to coordinate with him if option is available to you.
1212         /// In any-case, choice is up to the user.
1213         pub fn get_latest_holder_commitment_txn<L: Deref>(&self, logger: &L) -> Vec<Transaction>
1214         where L::Target: Logger {
1215                 self.inner.lock().unwrap().get_latest_holder_commitment_txn(logger)
1216         }
1217
1218         /// Unsafe test-only version of get_latest_holder_commitment_txn used by our test framework
1219         /// to bypass HolderCommitmentTransaction state update lockdown after signature and generate
1220         /// revoked commitment transaction.
1221         #[cfg(any(test, feature = "unsafe_revoked_tx_signing"))]
1222         pub fn unsafe_get_latest_holder_commitment_txn<L: Deref>(&self, logger: &L) -> Vec<Transaction>
1223         where L::Target: Logger {
1224                 self.inner.lock().unwrap().unsafe_get_latest_holder_commitment_txn(logger)
1225         }
1226
1227         /// Processes transactions in a newly connected block, which may result in any of the following:
1228         /// - update the monitor's state against resolved HTLCs
1229         /// - punish the counterparty in the case of seeing a revoked commitment transaction
1230         /// - force close the channel and claim/timeout incoming/outgoing HTLCs if near expiration
1231         /// - detect settled outputs for later spending
1232         /// - schedule and bump any in-flight claims
1233         ///
1234         /// Returns any new outputs to watch from `txdata`; after called, these are also included in
1235         /// [`get_outputs_to_watch`].
1236         ///
1237         /// [`get_outputs_to_watch`]: #method.get_outputs_to_watch
1238         pub fn block_connected<B: Deref, F: Deref, L: Deref>(
1239                 &self,
1240                 header: &BlockHeader,
1241                 txdata: &TransactionData,
1242                 height: u32,
1243                 broadcaster: B,
1244                 fee_estimator: F,
1245                 logger: L,
1246         ) -> Vec<(Txid, Vec<(u32, TxOut)>)>
1247         where
1248                 B::Target: BroadcasterInterface,
1249                 F::Target: FeeEstimator,
1250                 L::Target: Logger,
1251         {
1252                 self.inner.lock().unwrap().block_connected(
1253                         header, txdata, height, broadcaster, fee_estimator, logger)
1254         }
1255
1256         /// Determines if the disconnected block contained any transactions of interest and updates
1257         /// appropriately.
1258         pub fn block_disconnected<B: Deref, F: Deref, L: Deref>(
1259                 &self,
1260                 header: &BlockHeader,
1261                 height: u32,
1262                 broadcaster: B,
1263                 fee_estimator: F,
1264                 logger: L,
1265         ) where
1266                 B::Target: BroadcasterInterface,
1267                 F::Target: FeeEstimator,
1268                 L::Target: Logger,
1269         {
1270                 self.inner.lock().unwrap().block_disconnected(
1271                         header, height, broadcaster, fee_estimator, logger)
1272         }
1273 }
1274
1275 impl<Signer: Sign> ChannelMonitorImpl<Signer> {
1276         /// Inserts a revocation secret into this channel monitor. Prunes old preimages if neither
1277         /// needed by holder commitment transactions HTCLs nor by counterparty ones. Unless we haven't already seen
1278         /// counterparty commitment transaction's secret, they are de facto pruned (we can use revocation key).
1279         fn provide_secret(&mut self, idx: u64, secret: [u8; 32]) -> Result<(), MonitorUpdateError> {
1280                 if let Err(()) = self.commitment_secrets.provide_secret(idx, secret) {
1281                         return Err(MonitorUpdateError("Previous secret did not match new one"));
1282                 }
1283
1284                 // Prune HTLCs from the previous counterparty commitment tx so we don't generate failure/fulfill
1285                 // events for now-revoked/fulfilled HTLCs.
1286                 if let Some(txid) = self.prev_counterparty_commitment_txid.take() {
1287                         for &mut (_, ref mut source) in self.counterparty_claimable_outpoints.get_mut(&txid).unwrap() {
1288                                 *source = None;
1289                         }
1290                 }
1291
1292                 if !self.payment_preimages.is_empty() {
1293                         let cur_holder_signed_commitment_tx = &self.current_holder_commitment_tx;
1294                         let prev_holder_signed_commitment_tx = self.prev_holder_signed_commitment_tx.as_ref();
1295                         let min_idx = self.get_min_seen_secret();
1296                         let counterparty_hash_commitment_number = &mut self.counterparty_hash_commitment_number;
1297
1298                         self.payment_preimages.retain(|&k, _| {
1299                                 for &(ref htlc, _, _) in cur_holder_signed_commitment_tx.htlc_outputs.iter() {
1300                                         if k == htlc.payment_hash {
1301                                                 return true
1302                                         }
1303                                 }
1304                                 if let Some(prev_holder_commitment_tx) = prev_holder_signed_commitment_tx {
1305                                         for &(ref htlc, _, _) in prev_holder_commitment_tx.htlc_outputs.iter() {
1306                                                 if k == htlc.payment_hash {
1307                                                         return true
1308                                                 }
1309                                         }
1310                                 }
1311                                 let contains = if let Some(cn) = counterparty_hash_commitment_number.get(&k) {
1312                                         if *cn < min_idx {
1313                                                 return true
1314                                         }
1315                                         true
1316                                 } else { false };
1317                                 if contains {
1318                                         counterparty_hash_commitment_number.remove(&k);
1319                                 }
1320                                 false
1321                         });
1322                 }
1323
1324                 Ok(())
1325         }
1326
1327         pub(crate) fn provide_latest_counterparty_commitment_tx<L: Deref>(&mut self, txid: Txid, htlc_outputs: Vec<(HTLCOutputInCommitment, Option<Box<HTLCSource>>)>, commitment_number: u64, their_revocation_point: PublicKey, logger: &L) where L::Target: Logger {
1328                 // TODO: Encrypt the htlc_outputs data with the single-hash of the commitment transaction
1329                 // so that a remote monitor doesn't learn anything unless there is a malicious close.
1330                 // (only maybe, sadly we cant do the same for local info, as we need to be aware of
1331                 // timeouts)
1332                 for &(ref htlc, _) in &htlc_outputs {
1333                         self.counterparty_hash_commitment_number.insert(htlc.payment_hash, commitment_number);
1334                 }
1335
1336                 log_trace!(logger, "Tracking new counterparty commitment transaction with txid {} at commitment number {} with {} HTLC outputs", txid, commitment_number, htlc_outputs.len());
1337                 self.prev_counterparty_commitment_txid = self.current_counterparty_commitment_txid.take();
1338                 self.current_counterparty_commitment_txid = Some(txid);
1339                 self.counterparty_claimable_outpoints.insert(txid, htlc_outputs.clone());
1340                 self.current_counterparty_commitment_number = commitment_number;
1341                 //TODO: Merge this into the other per-counterparty-transaction output storage stuff
1342                 match self.their_cur_revocation_points {
1343                         Some(old_points) => {
1344                                 if old_points.0 == commitment_number + 1 {
1345                                         self.their_cur_revocation_points = Some((old_points.0, old_points.1, Some(their_revocation_point)));
1346                                 } else if old_points.0 == commitment_number + 2 {
1347                                         if let Some(old_second_point) = old_points.2 {
1348                                                 self.their_cur_revocation_points = Some((old_points.0 - 1, old_second_point, Some(their_revocation_point)));
1349                                         } else {
1350                                                 self.their_cur_revocation_points = Some((commitment_number, their_revocation_point, None));
1351                                         }
1352                                 } else {
1353                                         self.their_cur_revocation_points = Some((commitment_number, their_revocation_point, None));
1354                                 }
1355                         },
1356                         None => {
1357                                 self.their_cur_revocation_points = Some((commitment_number, their_revocation_point, None));
1358                         }
1359                 }
1360                 let mut htlcs = Vec::with_capacity(htlc_outputs.len());
1361                 for htlc in htlc_outputs {
1362                         if htlc.0.transaction_output_index.is_some() {
1363                                 htlcs.push(htlc.0);
1364                         }
1365                 }
1366                 self.counterparty_tx_cache.per_htlc.insert(txid, htlcs);
1367         }
1368
1369         /// Informs this monitor of the latest holder (ie broadcastable) commitment transaction. The
1370         /// monitor watches for timeouts and may broadcast it if we approach such a timeout. Thus, it
1371         /// is important that any clones of this channel monitor (including remote clones) by kept
1372         /// up-to-date as our holder commitment transaction is updated.
1373         /// Panics if set_on_holder_tx_csv has never been called.
1374         fn provide_latest_holder_commitment_tx(&mut self, holder_commitment_tx: HolderCommitmentTransaction, htlc_outputs: Vec<(HTLCOutputInCommitment, Option<Signature>, Option<HTLCSource>)>) -> Result<(), MonitorUpdateError> {
1375                 // block for Rust 1.34 compat
1376                 let mut new_holder_commitment_tx = {
1377                         let trusted_tx = holder_commitment_tx.trust();
1378                         let txid = trusted_tx.txid();
1379                         let tx_keys = trusted_tx.keys();
1380                         self.current_holder_commitment_number = trusted_tx.commitment_number();
1381                         HolderSignedTx {
1382                                 txid,
1383                                 revocation_key: tx_keys.revocation_key,
1384                                 a_htlc_key: tx_keys.broadcaster_htlc_key,
1385                                 b_htlc_key: tx_keys.countersignatory_htlc_key,
1386                                 delayed_payment_key: tx_keys.broadcaster_delayed_payment_key,
1387                                 per_commitment_point: tx_keys.per_commitment_point,
1388                                 feerate_per_kw: trusted_tx.feerate_per_kw(),
1389                                 htlc_outputs,
1390                         }
1391                 };
1392                 self.onchain_tx_handler.provide_latest_holder_tx(holder_commitment_tx);
1393                 mem::swap(&mut new_holder_commitment_tx, &mut self.current_holder_commitment_tx);
1394                 self.prev_holder_signed_commitment_tx = Some(new_holder_commitment_tx);
1395                 if self.holder_tx_signed {
1396                         return Err(MonitorUpdateError("Latest holder commitment signed has already been signed, update is rejected"));
1397                 }
1398                 Ok(())
1399         }
1400
1401         /// Provides a payment_hash->payment_preimage mapping. Will be automatically pruned when all
1402         /// commitment_tx_infos which contain the payment hash have been revoked.
1403         fn provide_payment_preimage<B: Deref, F: Deref, L: Deref>(&mut self, payment_hash: &PaymentHash, payment_preimage: &PaymentPreimage, broadcaster: &B, fee_estimator: &F, logger: &L)
1404         where B::Target: BroadcasterInterface,
1405                     F::Target: FeeEstimator,
1406                     L::Target: Logger,
1407         {
1408                 self.payment_preimages.insert(payment_hash.clone(), payment_preimage.clone());
1409
1410                 // If the channel is force closed, try to claim the output from this preimage.
1411                 // First check if a counterparty commitment transaction has been broadcasted:
1412                 macro_rules! claim_htlcs {
1413                         ($commitment_number: expr, $txid: expr) => {
1414                                 let htlc_claim_reqs = self.get_counterparty_htlc_output_claim_reqs($commitment_number, $txid, None);
1415                                 self.onchain_tx_handler.update_claims_view(&Vec::new(), htlc_claim_reqs, None, broadcaster, fee_estimator, logger);
1416                         }
1417                 }
1418                 if let Some(txid) = self.current_counterparty_commitment_txid {
1419                         if let Some(commitment_number) = self.counterparty_commitment_txn_on_chain.get(&txid) {
1420                                 claim_htlcs!(*commitment_number, txid);
1421                                 return;
1422                         }
1423                 }
1424                 if let Some(txid) = self.prev_counterparty_commitment_txid {
1425                         if let Some(commitment_number) = self.counterparty_commitment_txn_on_chain.get(&txid) {
1426                                 claim_htlcs!(*commitment_number, txid);
1427                                 return;
1428                         }
1429                 }
1430
1431                 // Then if a holder commitment transaction has been seen on-chain, broadcast transactions
1432                 // claiming the HTLC output from each of the holder commitment transactions.
1433                 // Note that we can't just use `self.holder_tx_signed`, because that only covers the case where
1434                 // *we* sign a holder commitment transaction, not when e.g. a watchtower broadcasts one of our
1435                 // holder commitment transactions.
1436                 if self.broadcasted_holder_revokable_script.is_some() {
1437                         let (claim_reqs, _) = self.get_broadcasted_holder_claims(&self.current_holder_commitment_tx);
1438                         self.onchain_tx_handler.update_claims_view(&Vec::new(), claim_reqs, None, broadcaster, fee_estimator, logger);
1439                         if let Some(ref tx) = self.prev_holder_signed_commitment_tx {
1440                                 let (claim_reqs, _) = self.get_broadcasted_holder_claims(&tx);
1441                                 self.onchain_tx_handler.update_claims_view(&Vec::new(), claim_reqs, None, broadcaster, fee_estimator, logger);
1442                         }
1443                 }
1444         }
1445
1446         pub(crate) fn broadcast_latest_holder_commitment_txn<B: Deref, L: Deref>(&mut self, broadcaster: &B, logger: &L)
1447                 where B::Target: BroadcasterInterface,
1448                                         L::Target: Logger,
1449         {
1450                 for tx in self.get_latest_holder_commitment_txn(logger).iter() {
1451                         broadcaster.broadcast_transaction(tx);
1452                 }
1453                 self.pending_monitor_events.push(MonitorEvent::CommitmentTxBroadcasted(self.funding_info.0));
1454         }
1455
1456         pub fn update_monitor<B: Deref, F: Deref, L: Deref>(&mut self, updates: &ChannelMonitorUpdate, broadcaster: &B, fee_estimator: &F, logger: &L) -> Result<(), MonitorUpdateError>
1457         where B::Target: BroadcasterInterface,
1458                     F::Target: FeeEstimator,
1459                     L::Target: Logger,
1460         {
1461                 // ChannelMonitor updates may be applied after force close if we receive a
1462                 // preimage for a broadcasted commitment transaction HTLC output that we'd
1463                 // like to claim on-chain. If this is the case, we no longer have guaranteed
1464                 // access to the monitor's update ID, so we use a sentinel value instead.
1465                 if updates.update_id == CLOSED_CHANNEL_UPDATE_ID {
1466                         match updates.updates[0] {
1467                                 ChannelMonitorUpdateStep::PaymentPreimage { .. } => {},
1468                                 _ => panic!("Attempted to apply post-force-close ChannelMonitorUpdate that wasn't providing a payment preimage"),
1469                         }
1470                         assert_eq!(updates.updates.len(), 1);
1471                 } else if self.latest_update_id + 1 != updates.update_id {
1472                         panic!("Attempted to apply ChannelMonitorUpdates out of order, check the update_id before passing an update to update_monitor!");
1473                 }
1474                 for update in updates.updates.iter() {
1475                         match update {
1476                                 ChannelMonitorUpdateStep::LatestHolderCommitmentTXInfo { commitment_tx, htlc_outputs } => {
1477                                         log_trace!(logger, "Updating ChannelMonitor with latest holder commitment transaction info");
1478                                         if self.lockdown_from_offchain { panic!(); }
1479                                         self.provide_latest_holder_commitment_tx(commitment_tx.clone(), htlc_outputs.clone())?
1480                                 }
1481                                 ChannelMonitorUpdateStep::LatestCounterpartyCommitmentTXInfo { commitment_txid, htlc_outputs, commitment_number, their_revocation_point } => {
1482                                         log_trace!(logger, "Updating ChannelMonitor with latest counterparty commitment transaction info");
1483                                         self.provide_latest_counterparty_commitment_tx(*commitment_txid, htlc_outputs.clone(), *commitment_number, *their_revocation_point, logger)
1484                                 },
1485                                 ChannelMonitorUpdateStep::PaymentPreimage { payment_preimage } => {
1486                                         log_trace!(logger, "Updating ChannelMonitor with payment preimage");
1487                                         self.provide_payment_preimage(&PaymentHash(Sha256::hash(&payment_preimage.0[..]).into_inner()), &payment_preimage, broadcaster, fee_estimator, logger)
1488                                 },
1489                                 ChannelMonitorUpdateStep::CommitmentSecret { idx, secret } => {
1490                                         log_trace!(logger, "Updating ChannelMonitor with commitment secret");
1491                                         self.provide_secret(*idx, *secret)?
1492                                 },
1493                                 ChannelMonitorUpdateStep::ChannelForceClosed { should_broadcast } => {
1494                                         log_trace!(logger, "Updating ChannelMonitor: channel force closed, should broadcast: {}", should_broadcast);
1495                                         self.lockdown_from_offchain = true;
1496                                         if *should_broadcast {
1497                                                 self.broadcast_latest_holder_commitment_txn(broadcaster, logger);
1498                                         } else {
1499                                                 log_error!(logger, "You have a toxic holder commitment transaction avaible in channel monitor, read comment in ChannelMonitor::get_latest_holder_commitment_txn to be informed of manual action to take");
1500                                         }
1501                                 }
1502                         }
1503                 }
1504                 self.latest_update_id = updates.update_id;
1505                 Ok(())
1506         }
1507
1508         pub fn get_latest_update_id(&self) -> u64 {
1509                 self.latest_update_id
1510         }
1511
1512         pub fn get_funding_txo(&self) -> &(OutPoint, Script) {
1513                 &self.funding_info
1514         }
1515
1516         pub fn get_outputs_to_watch(&self) -> &HashMap<Txid, Vec<(u32, Script)>> {
1517                 // If we've detected a counterparty commitment tx on chain, we must include it in the set
1518                 // of outputs to watch for spends of, otherwise we're likely to lose user funds. Because
1519                 // its trivial to do, double-check that here.
1520                 for (txid, _) in self.counterparty_commitment_txn_on_chain.iter() {
1521                         self.outputs_to_watch.get(txid).expect("Counterparty commitment txn which have been broadcast should have outputs registered");
1522                 }
1523                 &self.outputs_to_watch
1524         }
1525
1526         pub fn get_and_clear_pending_monitor_events(&mut self) -> Vec<MonitorEvent> {
1527                 let mut ret = Vec::new();
1528                 mem::swap(&mut ret, &mut self.pending_monitor_events);
1529                 ret
1530         }
1531
1532         pub fn get_and_clear_pending_events(&mut self) -> Vec<Event> {
1533                 let mut ret = Vec::new();
1534                 mem::swap(&mut ret, &mut self.pending_events);
1535                 ret
1536         }
1537
1538         /// Can only fail if idx is < get_min_seen_secret
1539         fn get_secret(&self, idx: u64) -> Option<[u8; 32]> {
1540                 self.commitment_secrets.get_secret(idx)
1541         }
1542
1543         pub(crate) fn get_min_seen_secret(&self) -> u64 {
1544                 self.commitment_secrets.get_min_seen_secret()
1545         }
1546
1547         pub(crate) fn get_cur_counterparty_commitment_number(&self) -> u64 {
1548                 self.current_counterparty_commitment_number
1549         }
1550
1551         pub(crate) fn get_cur_holder_commitment_number(&self) -> u64 {
1552                 self.current_holder_commitment_number
1553         }
1554
1555         /// Attempts to claim a counterparty commitment transaction's outputs using the revocation key and
1556         /// data in counterparty_claimable_outpoints. Will directly claim any HTLC outputs which expire at a
1557         /// height > height + CLTV_SHARED_CLAIM_BUFFER. In any case, will install monitoring for
1558         /// HTLC-Success/HTLC-Timeout transactions.
1559         /// Return updates for HTLC pending in the channel and failed automatically by the broadcast of
1560         /// revoked counterparty commitment tx
1561         fn check_spend_counterparty_transaction<L: Deref>(&mut self, tx: &Transaction, height: u32, logger: &L) -> (Vec<ClaimRequest>, (Txid, Vec<(u32, TxOut)>)) where L::Target: Logger {
1562                 // Most secp and related errors trying to create keys means we have no hope of constructing
1563                 // a spend transaction...so we return no transactions to broadcast
1564                 let mut claimable_outpoints = Vec::new();
1565                 let mut watch_outputs = Vec::new();
1566
1567                 let commitment_txid = tx.txid(); //TODO: This is gonna be a performance bottleneck for watchtowers!
1568                 let per_commitment_option = self.counterparty_claimable_outpoints.get(&commitment_txid);
1569
1570                 macro_rules! ignore_error {
1571                         ( $thing : expr ) => {
1572                                 match $thing {
1573                                         Ok(a) => a,
1574                                         Err(_) => return (claimable_outpoints, (commitment_txid, watch_outputs))
1575                                 }
1576                         };
1577                 }
1578
1579                 let commitment_number = 0xffffffffffff - ((((tx.input[0].sequence as u64 & 0xffffff) << 3*8) | (tx.lock_time as u64 & 0xffffff)) ^ self.commitment_transaction_number_obscure_factor);
1580                 if commitment_number >= self.get_min_seen_secret() {
1581                         let secret = self.get_secret(commitment_number).unwrap();
1582                         let per_commitment_key = ignore_error!(SecretKey::from_slice(&secret));
1583                         let per_commitment_point = PublicKey::from_secret_key(&self.secp_ctx, &per_commitment_key);
1584                         let revocation_pubkey = ignore_error!(chan_utils::derive_public_revocation_key(&self.secp_ctx, &per_commitment_point, &self.holder_revocation_basepoint));
1585                         let delayed_key = ignore_error!(chan_utils::derive_public_key(&self.secp_ctx, &PublicKey::from_secret_key(&self.secp_ctx, &per_commitment_key), &self.counterparty_tx_cache.counterparty_delayed_payment_base_key));
1586
1587                         let revokeable_redeemscript = chan_utils::get_revokeable_redeemscript(&revocation_pubkey, self.counterparty_tx_cache.on_counterparty_tx_csv, &delayed_key);
1588                         let revokeable_p2wsh = revokeable_redeemscript.to_v0_p2wsh();
1589
1590                         // First, process non-htlc outputs (to_holder & to_counterparty)
1591                         for (idx, outp) in tx.output.iter().enumerate() {
1592                                 if outp.script_pubkey == revokeable_p2wsh {
1593                                         let witness_data = InputMaterial::Revoked { per_commitment_point, counterparty_delayed_payment_base_key: self.counterparty_tx_cache.counterparty_delayed_payment_base_key, counterparty_htlc_base_key: self.counterparty_tx_cache.counterparty_htlc_base_key, per_commitment_key, input_descriptor: InputDescriptors::RevokedOutput, amount: outp.value, htlc: None, on_counterparty_tx_csv: self.counterparty_tx_cache.on_counterparty_tx_csv};
1594                                         claimable_outpoints.push(ClaimRequest { absolute_timelock: height + self.counterparty_tx_cache.on_counterparty_tx_csv as u32, aggregable: true, outpoint: BitcoinOutPoint { txid: commitment_txid, vout: idx as u32 }, witness_data});
1595                                 }
1596                         }
1597
1598                         // Then, try to find revoked htlc outputs
1599                         if let Some(ref per_commitment_data) = per_commitment_option {
1600                                 for (_, &(ref htlc, _)) in per_commitment_data.iter().enumerate() {
1601                                         if let Some(transaction_output_index) = htlc.transaction_output_index {
1602                                                 if transaction_output_index as usize >= tx.output.len() ||
1603                                                                 tx.output[transaction_output_index as usize].value != htlc.amount_msat / 1000 {
1604                                                         return (claimable_outpoints, (commitment_txid, watch_outputs)); // Corrupted per_commitment_data, fuck this user
1605                                                 }
1606                                                 let witness_data = InputMaterial::Revoked { per_commitment_point, counterparty_delayed_payment_base_key: self.counterparty_tx_cache.counterparty_delayed_payment_base_key, counterparty_htlc_base_key: self.counterparty_tx_cache.counterparty_htlc_base_key, per_commitment_key, input_descriptor: if htlc.offered { InputDescriptors::RevokedOfferedHTLC } else { InputDescriptors::RevokedReceivedHTLC }, amount: tx.output[transaction_output_index as usize].value, htlc: Some(htlc.clone()), on_counterparty_tx_csv: self.counterparty_tx_cache.on_counterparty_tx_csv};
1607                                                 claimable_outpoints.push(ClaimRequest { absolute_timelock: htlc.cltv_expiry, aggregable: true, outpoint: BitcoinOutPoint { txid: commitment_txid, vout: transaction_output_index }, witness_data });
1608                                         }
1609                                 }
1610                         }
1611
1612                         // Last, track onchain revoked commitment transaction and fail backward outgoing HTLCs as payment path is broken
1613                         if !claimable_outpoints.is_empty() || per_commitment_option.is_some() { // ie we're confident this is actually ours
1614                                 // We're definitely a counterparty commitment transaction!
1615                                 log_trace!(logger, "Got broadcast of revoked counterparty commitment transaction, going to generate general spend tx with {} inputs", claimable_outpoints.len());
1616                                 for (idx, outp) in tx.output.iter().enumerate() {
1617                                         watch_outputs.push((idx as u32, outp.clone()));
1618                                 }
1619                                 self.counterparty_commitment_txn_on_chain.insert(commitment_txid, commitment_number);
1620
1621                                 macro_rules! check_htlc_fails {
1622                                         ($txid: expr, $commitment_tx: expr) => {
1623                                                 if let Some(ref outpoints) = self.counterparty_claimable_outpoints.get($txid) {
1624                                                         for &(ref htlc, ref source_option) in outpoints.iter() {
1625                                                                 if let &Some(ref source) = source_option {
1626                                                                         log_info!(logger, "Failing HTLC with payment_hash {} from {} counterparty commitment tx due to broadcast of revoked counterparty commitment transaction, waiting for confirmation (at height {})", log_bytes!(htlc.payment_hash.0), $commitment_tx, height + ANTI_REORG_DELAY - 1);
1627                                                                         match self.onchain_events_waiting_threshold_conf.entry(height + ANTI_REORG_DELAY - 1) {
1628                                                                                 hash_map::Entry::Occupied(mut entry) => {
1629                                                                                         let e = entry.get_mut();
1630                                                                                         e.retain(|ref event| {
1631                                                                                                 match **event {
1632                                                                                                         OnchainEvent::HTLCUpdate { ref htlc_update } => {
1633                                                                                                                 return htlc_update.0 != **source
1634                                                                                                         },
1635                                                                                                         _ => true
1636                                                                                                 }
1637                                                                                         });
1638                                                                                         e.push(OnchainEvent::HTLCUpdate { htlc_update: ((**source).clone(), htlc.payment_hash.clone())});
1639                                                                                 }
1640                                                                                 hash_map::Entry::Vacant(entry) => {
1641                                                                                         entry.insert(vec![OnchainEvent::HTLCUpdate { htlc_update: ((**source).clone(), htlc.payment_hash.clone())}]);
1642                                                                                 }
1643                                                                         }
1644                                                                 }
1645                                                         }
1646                                                 }
1647                                         }
1648                                 }
1649                                 if let Some(ref txid) = self.current_counterparty_commitment_txid {
1650                                         check_htlc_fails!(txid, "current");
1651                                 }
1652                                 if let Some(ref txid) = self.prev_counterparty_commitment_txid {
1653                                         check_htlc_fails!(txid, "counterparty");
1654                                 }
1655                                 // No need to check holder commitment txn, symmetric HTLCSource must be present as per-htlc data on counterparty commitment tx
1656                         }
1657                 } else if let Some(per_commitment_data) = per_commitment_option {
1658                         // While this isn't useful yet, there is a potential race where if a counterparty
1659                         // revokes a state at the same time as the commitment transaction for that state is
1660                         // confirmed, and the watchtower receives the block before the user, the user could
1661                         // upload a new ChannelMonitor with the revocation secret but the watchtower has
1662                         // already processed the block, resulting in the counterparty_commitment_txn_on_chain entry
1663                         // not being generated by the above conditional. Thus, to be safe, we go ahead and
1664                         // insert it here.
1665                         for (idx, outp) in tx.output.iter().enumerate() {
1666                                 watch_outputs.push((idx as u32, outp.clone()));
1667                         }
1668                         self.counterparty_commitment_txn_on_chain.insert(commitment_txid, commitment_number);
1669
1670                         log_trace!(logger, "Got broadcast of non-revoked counterparty commitment transaction {}", commitment_txid);
1671
1672                         macro_rules! check_htlc_fails {
1673                                 ($txid: expr, $commitment_tx: expr, $id: tt) => {
1674                                         if let Some(ref latest_outpoints) = self.counterparty_claimable_outpoints.get($txid) {
1675                                                 $id: for &(ref htlc, ref source_option) in latest_outpoints.iter() {
1676                                                         if let &Some(ref source) = source_option {
1677                                                                 // Check if the HTLC is present in the commitment transaction that was
1678                                                                 // broadcast, but not if it was below the dust limit, which we should
1679                                                                 // fail backwards immediately as there is no way for us to learn the
1680                                                                 // payment_preimage.
1681                                                                 // Note that if the dust limit were allowed to change between
1682                                                                 // commitment transactions we'd want to be check whether *any*
1683                                                                 // broadcastable commitment transaction has the HTLC in it, but it
1684                                                                 // cannot currently change after channel initialization, so we don't
1685                                                                 // need to here.
1686                                                                 for &(ref broadcast_htlc, ref broadcast_source) in per_commitment_data.iter() {
1687                                                                         if broadcast_htlc.transaction_output_index.is_some() && Some(source) == broadcast_source.as_ref() {
1688                                                                                 continue $id;
1689                                                                         }
1690                                                                 }
1691                                                                 log_trace!(logger, "Failing HTLC with payment_hash {} from {} counterparty commitment tx due to broadcast of counterparty commitment transaction", log_bytes!(htlc.payment_hash.0), $commitment_tx);
1692                                                                 match self.onchain_events_waiting_threshold_conf.entry(height + ANTI_REORG_DELAY - 1) {
1693                                                                         hash_map::Entry::Occupied(mut entry) => {
1694                                                                                 let e = entry.get_mut();
1695                                                                                 e.retain(|ref event| {
1696                                                                                         match **event {
1697                                                                                                 OnchainEvent::HTLCUpdate { ref htlc_update } => {
1698                                                                                                         return htlc_update.0 != **source
1699                                                                                                 },
1700                                                                                                 _ => true
1701                                                                                         }
1702                                                                                 });
1703                                                                                 e.push(OnchainEvent::HTLCUpdate { htlc_update: ((**source).clone(), htlc.payment_hash.clone())});
1704                                                                         }
1705                                                                         hash_map::Entry::Vacant(entry) => {
1706                                                                                 entry.insert(vec![OnchainEvent::HTLCUpdate { htlc_update: ((**source).clone(), htlc.payment_hash.clone())}]);
1707                                                                         }
1708                                                                 }
1709                                                         }
1710                                                 }
1711                                         }
1712                                 }
1713                         }
1714                         if let Some(ref txid) = self.current_counterparty_commitment_txid {
1715                                 check_htlc_fails!(txid, "current", 'current_loop);
1716                         }
1717                         if let Some(ref txid) = self.prev_counterparty_commitment_txid {
1718                                 check_htlc_fails!(txid, "previous", 'prev_loop);
1719                         }
1720
1721                         let htlc_claim_reqs = self.get_counterparty_htlc_output_claim_reqs(commitment_number, commitment_txid, Some(tx));
1722                         for req in htlc_claim_reqs {
1723                                 claimable_outpoints.push(req);
1724                         }
1725
1726                 }
1727                 (claimable_outpoints, (commitment_txid, watch_outputs))
1728         }
1729
1730         fn get_counterparty_htlc_output_claim_reqs(&self, commitment_number: u64, commitment_txid: Txid, tx: Option<&Transaction>) -> Vec<ClaimRequest> {
1731                 let mut claims = Vec::new();
1732                 if let Some(htlc_outputs) = self.counterparty_claimable_outpoints.get(&commitment_txid) {
1733                         if let Some(revocation_points) = self.their_cur_revocation_points {
1734                                 let revocation_point_option =
1735                                         // If the counterparty commitment tx is the latest valid state, use their latest
1736                                         // per-commitment point
1737                                         if revocation_points.0 == commitment_number { Some(&revocation_points.1) }
1738                                         else if let Some(point) = revocation_points.2.as_ref() {
1739                                                 // If counterparty commitment tx is the state previous to the latest valid state, use
1740                                                 // their previous per-commitment point (non-atomicity of revocation means it's valid for
1741                                                 // them to temporarily have two valid commitment txns from our viewpoint)
1742                                                 if revocation_points.0 == commitment_number + 1 { Some(point) } else { None }
1743                                         } else { None };
1744                                 if let Some(revocation_point) = revocation_point_option {
1745                                         for (_, &(ref htlc, _)) in htlc_outputs.iter().enumerate() {
1746                                                 if let Some(transaction_output_index) = htlc.transaction_output_index {
1747                                                         if let Some(transaction) = tx {
1748                                                                 if transaction_output_index as usize >= transaction.output.len() ||
1749                                                                         transaction.output[transaction_output_index as usize].value != htlc.amount_msat / 1000 {
1750                                                                                 return claims; // Corrupted per_commitment_data, fuck this user
1751                                                                         }
1752                                                         }
1753                                                         let preimage =
1754                                                                 if htlc.offered {
1755                                                                         if let Some(p) = self.payment_preimages.get(&htlc.payment_hash) {
1756                                                                                 Some(*p)
1757                                                                         } else { None }
1758                                                                 } else { None };
1759                                                         let aggregable = if !htlc.offered { false } else { true };
1760                                                         if preimage.is_some() || !htlc.offered {
1761                                                                 let witness_data = InputMaterial::CounterpartyHTLC { per_commitment_point: *revocation_point, counterparty_delayed_payment_base_key: self.counterparty_tx_cache.counterparty_delayed_payment_base_key, counterparty_htlc_base_key: self.counterparty_tx_cache.counterparty_htlc_base_key, preimage, htlc: htlc.clone() };
1762                                                                 claims.push(ClaimRequest { absolute_timelock: htlc.cltv_expiry, aggregable, outpoint: BitcoinOutPoint { txid: commitment_txid, vout: transaction_output_index }, witness_data });
1763                                                         }
1764                                                 }
1765                                         }
1766                                 }
1767                         }
1768                 }
1769                 claims
1770         }
1771
1772         /// Attempts to claim a counterparty HTLC-Success/HTLC-Timeout's outputs using the revocation key
1773         fn check_spend_counterparty_htlc<L: Deref>(&mut self, tx: &Transaction, commitment_number: u64, height: u32, logger: &L) -> (Vec<ClaimRequest>, Option<(Txid, Vec<(u32, TxOut)>)>) where L::Target: Logger {
1774                 let htlc_txid = tx.txid();
1775                 if tx.input.len() != 1 || tx.output.len() != 1 || tx.input[0].witness.len() != 5 {
1776                         return (Vec::new(), None)
1777                 }
1778
1779                 macro_rules! ignore_error {
1780                         ( $thing : expr ) => {
1781                                 match $thing {
1782                                         Ok(a) => a,
1783                                         Err(_) => return (Vec::new(), None)
1784                                 }
1785                         };
1786                 }
1787
1788                 let secret = if let Some(secret) = self.get_secret(commitment_number) { secret } else { return (Vec::new(), None); };
1789                 let per_commitment_key = ignore_error!(SecretKey::from_slice(&secret));
1790                 let per_commitment_point = PublicKey::from_secret_key(&self.secp_ctx, &per_commitment_key);
1791
1792                 log_trace!(logger, "Counterparty HTLC broadcast {}:{}", htlc_txid, 0);
1793                 let witness_data = InputMaterial::Revoked { per_commitment_point, counterparty_delayed_payment_base_key: self.counterparty_tx_cache.counterparty_delayed_payment_base_key, counterparty_htlc_base_key: self.counterparty_tx_cache.counterparty_htlc_base_key,  per_commitment_key, input_descriptor: InputDescriptors::RevokedOutput, amount: tx.output[0].value, htlc: None, on_counterparty_tx_csv: self.counterparty_tx_cache.on_counterparty_tx_csv };
1794                 let claimable_outpoints = vec!(ClaimRequest { absolute_timelock: height + self.counterparty_tx_cache.on_counterparty_tx_csv as u32, aggregable: true, outpoint: BitcoinOutPoint { txid: htlc_txid, vout: 0}, witness_data });
1795                 let outputs = vec![(0, tx.output[0].clone())];
1796                 (claimable_outpoints, Some((htlc_txid, outputs)))
1797         }
1798
1799         // Returns (1) `ClaimRequest`s that can be given to the OnChainTxHandler, so that the handler can
1800         // broadcast transactions claiming holder HTLC commitment outputs and (2) a holder revokable
1801         // script so we can detect whether a holder transaction has been seen on-chain.
1802         fn get_broadcasted_holder_claims(&self, holder_tx: &HolderSignedTx) -> (Vec<ClaimRequest>, Option<(Script, PublicKey, PublicKey)>) {
1803                 let mut claim_requests = Vec::with_capacity(holder_tx.htlc_outputs.len());
1804
1805                 let redeemscript = chan_utils::get_revokeable_redeemscript(&holder_tx.revocation_key, self.on_holder_tx_csv, &holder_tx.delayed_payment_key);
1806                 let broadcasted_holder_revokable_script = Some((redeemscript.to_v0_p2wsh(), holder_tx.per_commitment_point.clone(), holder_tx.revocation_key.clone()));
1807
1808                 for &(ref htlc, _, _) in holder_tx.htlc_outputs.iter() {
1809                         if let Some(transaction_output_index) = htlc.transaction_output_index {
1810                                 claim_requests.push(ClaimRequest { absolute_timelock: ::std::u32::MAX, aggregable: false, outpoint: BitcoinOutPoint { txid: holder_tx.txid, vout: transaction_output_index as u32 },
1811                                         witness_data: InputMaterial::HolderHTLC {
1812                                                 preimage: if !htlc.offered {
1813                                                                 if let Some(preimage) = self.payment_preimages.get(&htlc.payment_hash) {
1814                                                                         Some(preimage.clone())
1815                                                                 } else {
1816                                                                         // We can't build an HTLC-Success transaction without the preimage
1817                                                                         continue;
1818                                                                 }
1819                                                         } else { None },
1820                                                 amount: htlc.amount_msat,
1821                                 }});
1822                         }
1823                 }
1824
1825                 (claim_requests, broadcasted_holder_revokable_script)
1826         }
1827
1828         // Returns holder HTLC outputs to watch and react to in case of spending.
1829         fn get_broadcasted_holder_watch_outputs(&self, holder_tx: &HolderSignedTx, commitment_tx: &Transaction) -> Vec<(u32, TxOut)> {
1830                 let mut watch_outputs = Vec::with_capacity(holder_tx.htlc_outputs.len());
1831                 for &(ref htlc, _, _) in holder_tx.htlc_outputs.iter() {
1832                         if let Some(transaction_output_index) = htlc.transaction_output_index {
1833                                 watch_outputs.push((transaction_output_index, commitment_tx.output[transaction_output_index as usize].clone()));
1834                         }
1835                 }
1836                 watch_outputs
1837         }
1838
1839         /// Attempts to claim any claimable HTLCs in a commitment transaction which was not (yet)
1840         /// revoked using data in holder_claimable_outpoints.
1841         /// Should not be used if check_spend_revoked_transaction succeeds.
1842         fn check_spend_holder_transaction<L: Deref>(&mut self, tx: &Transaction, height: u32, logger: &L) -> (Vec<ClaimRequest>, (Txid, Vec<(u32, TxOut)>)) where L::Target: Logger {
1843                 let commitment_txid = tx.txid();
1844                 let mut claim_requests = Vec::new();
1845                 let mut watch_outputs = Vec::new();
1846
1847                 macro_rules! wait_threshold_conf {
1848                         ($height: expr, $source: expr, $commitment_tx: expr, $payment_hash: expr) => {
1849                                 log_trace!(logger, "Failing HTLC with payment_hash {} from {} holder commitment tx due to broadcast of transaction, waiting confirmation (at height{})", log_bytes!($payment_hash.0), $commitment_tx, height + ANTI_REORG_DELAY - 1);
1850                                 match self.onchain_events_waiting_threshold_conf.entry($height + ANTI_REORG_DELAY - 1) {
1851                                         hash_map::Entry::Occupied(mut entry) => {
1852                                                 let e = entry.get_mut();
1853                                                 e.retain(|ref event| {
1854                                                         match **event {
1855                                                                 OnchainEvent::HTLCUpdate { ref htlc_update } => {
1856                                                                         return htlc_update.0 != $source
1857                                                                 },
1858                                                                 _ => true
1859                                                         }
1860                                                 });
1861                                                 e.push(OnchainEvent::HTLCUpdate { htlc_update: ($source, $payment_hash)});
1862                                         }
1863                                         hash_map::Entry::Vacant(entry) => {
1864                                                 entry.insert(vec![OnchainEvent::HTLCUpdate { htlc_update: ($source, $payment_hash)}]);
1865                                         }
1866                                 }
1867                         }
1868                 }
1869
1870                 macro_rules! append_onchain_update {
1871                         ($updates: expr, $to_watch: expr) => {
1872                                 claim_requests = $updates.0;
1873                                 self.broadcasted_holder_revokable_script = $updates.1;
1874                                 watch_outputs.append(&mut $to_watch);
1875                         }
1876                 }
1877
1878                 // HTLCs set may differ between last and previous holder commitment txn, in case of one them hitting chain, ensure we cancel all HTLCs backward
1879                 let mut is_holder_tx = false;
1880
1881                 if self.current_holder_commitment_tx.txid == commitment_txid {
1882                         is_holder_tx = true;
1883                         log_trace!(logger, "Got latest holder commitment tx broadcast, searching for available HTLCs to claim");
1884                         let res = self.get_broadcasted_holder_claims(&self.current_holder_commitment_tx);
1885                         let mut to_watch = self.get_broadcasted_holder_watch_outputs(&self.current_holder_commitment_tx, tx);
1886                         append_onchain_update!(res, to_watch);
1887                 } else if let &Some(ref holder_tx) = &self.prev_holder_signed_commitment_tx {
1888                         if holder_tx.txid == commitment_txid {
1889                                 is_holder_tx = true;
1890                                 log_trace!(logger, "Got previous holder commitment tx broadcast, searching for available HTLCs to claim");
1891                                 let res = self.get_broadcasted_holder_claims(holder_tx);
1892                                 let mut to_watch = self.get_broadcasted_holder_watch_outputs(holder_tx, tx);
1893                                 append_onchain_update!(res, to_watch);
1894                         }
1895                 }
1896
1897                 macro_rules! fail_dust_htlcs_after_threshold_conf {
1898                         ($holder_tx: expr) => {
1899                                 for &(ref htlc, _, ref source) in &$holder_tx.htlc_outputs {
1900                                         if htlc.transaction_output_index.is_none() {
1901                                                 if let &Some(ref source) = source {
1902                                                         wait_threshold_conf!(height, source.clone(), "lastest", htlc.payment_hash.clone());
1903                                                 }
1904                                         }
1905                                 }
1906                         }
1907                 }
1908
1909                 if is_holder_tx {
1910                         fail_dust_htlcs_after_threshold_conf!(self.current_holder_commitment_tx);
1911                         if let &Some(ref holder_tx) = &self.prev_holder_signed_commitment_tx {
1912                                 fail_dust_htlcs_after_threshold_conf!(holder_tx);
1913                         }
1914                 }
1915
1916                 (claim_requests, (commitment_txid, watch_outputs))
1917         }
1918
1919         pub fn get_latest_holder_commitment_txn<L: Deref>(&mut self, logger: &L) -> Vec<Transaction> where L::Target: Logger {
1920                 log_trace!(logger, "Getting signed latest holder commitment transaction!");
1921                 self.holder_tx_signed = true;
1922                 let commitment_tx = self.onchain_tx_handler.get_fully_signed_holder_tx(&self.funding_redeemscript);
1923                 let txid = commitment_tx.txid();
1924                 let mut res = vec![commitment_tx];
1925                 for htlc in self.current_holder_commitment_tx.htlc_outputs.iter() {
1926                         if let Some(vout) = htlc.0.transaction_output_index {
1927                                 let preimage = if !htlc.0.offered {
1928                                         if let Some(preimage) = self.payment_preimages.get(&htlc.0.payment_hash) { Some(preimage.clone()) } else {
1929                                                 // We can't build an HTLC-Success transaction without the preimage
1930                                                 continue;
1931                                         }
1932                                 } else { None };
1933                                 if let Some(htlc_tx) = self.onchain_tx_handler.get_fully_signed_htlc_tx(
1934                                         &::bitcoin::OutPoint { txid, vout }, &preimage) {
1935                                         res.push(htlc_tx);
1936                                 }
1937                         }
1938                 }
1939                 // We throw away the generated waiting_first_conf data as we aren't (yet) confirmed and we don't actually know what the caller wants to do.
1940                 // The data will be re-generated and tracked in check_spend_holder_transaction if we get a confirmation.
1941                 return res;
1942         }
1943
1944         #[cfg(any(test,feature = "unsafe_revoked_tx_signing"))]
1945         fn unsafe_get_latest_holder_commitment_txn<L: Deref>(&mut self, logger: &L) -> Vec<Transaction> where L::Target: Logger {
1946                 log_trace!(logger, "Getting signed copy of latest holder commitment transaction!");
1947                 let commitment_tx = self.onchain_tx_handler.get_fully_signed_copy_holder_tx(&self.funding_redeemscript);
1948                 let txid = commitment_tx.txid();
1949                 let mut res = vec![commitment_tx];
1950                 for htlc in self.current_holder_commitment_tx.htlc_outputs.iter() {
1951                         if let Some(vout) = htlc.0.transaction_output_index {
1952                                 let preimage = if !htlc.0.offered {
1953                                         if let Some(preimage) = self.payment_preimages.get(&htlc.0.payment_hash) { Some(preimage.clone()) } else {
1954                                                 // We can't build an HTLC-Success transaction without the preimage
1955                                                 continue;
1956                                         }
1957                                 } else { None };
1958                                 if let Some(htlc_tx) = self.onchain_tx_handler.unsafe_get_fully_signed_htlc_tx(
1959                                         &::bitcoin::OutPoint { txid, vout }, &preimage) {
1960                                         res.push(htlc_tx);
1961                                 }
1962                         }
1963                 }
1964                 return res
1965         }
1966
1967         pub fn block_connected<B: Deref, F: Deref, L: Deref>(&mut self, header: &BlockHeader, txdata: &TransactionData, height: u32, broadcaster: B, fee_estimator: F, logger: L)-> Vec<(Txid, Vec<(u32, TxOut)>)>
1968                 where B::Target: BroadcasterInterface,
1969                       F::Target: FeeEstimator,
1970                                         L::Target: Logger,
1971         {
1972                 let txn_matched = self.filter_block(txdata);
1973                 for tx in &txn_matched {
1974                         let mut output_val = 0;
1975                         for out in tx.output.iter() {
1976                                 if out.value > 21_000_000_0000_0000 { panic!("Value-overflowing transaction provided to block connected"); }
1977                                 output_val += out.value;
1978                                 if output_val > 21_000_000_0000_0000 { panic!("Value-overflowing transaction provided to block connected"); }
1979                         }
1980                 }
1981
1982                 let block_hash = header.block_hash();
1983                 log_trace!(logger, "Block {} at height {} connected with {} txn matched", block_hash, height, txn_matched.len());
1984
1985                 let mut watch_outputs = Vec::new();
1986                 let mut claimable_outpoints = Vec::new();
1987                 for tx in &txn_matched {
1988                         if tx.input.len() == 1 {
1989                                 // Assuming our keys were not leaked (in which case we're screwed no matter what),
1990                                 // commitment transactions and HTLC transactions will all only ever have one input,
1991                                 // which is an easy way to filter out any potential non-matching txn for lazy
1992                                 // filters.
1993                                 let prevout = &tx.input[0].previous_output;
1994                                 if prevout.txid == self.funding_info.0.txid && prevout.vout == self.funding_info.0.index as u32 {
1995                                         if (tx.input[0].sequence >> 8*3) as u8 == 0x80 && (tx.lock_time >> 8*3) as u8 == 0x20 {
1996                                                 let (mut new_outpoints, new_outputs) = self.check_spend_counterparty_transaction(&tx, height, &logger);
1997                                                 if !new_outputs.1.is_empty() {
1998                                                         watch_outputs.push(new_outputs);
1999                                                 }
2000                                                 if new_outpoints.is_empty() {
2001                                                         let (mut new_outpoints, new_outputs) = self.check_spend_holder_transaction(&tx, height, &logger);
2002                                                         if !new_outputs.1.is_empty() {
2003                                                                 watch_outputs.push(new_outputs);
2004                                                         }
2005                                                         claimable_outpoints.append(&mut new_outpoints);
2006                                                 }
2007                                                 claimable_outpoints.append(&mut new_outpoints);
2008                                         }
2009                                 } else {
2010                                         if let Some(&commitment_number) = self.counterparty_commitment_txn_on_chain.get(&prevout.txid) {
2011                                                 let (mut new_outpoints, new_outputs_option) = self.check_spend_counterparty_htlc(&tx, commitment_number, height, &logger);
2012                                                 claimable_outpoints.append(&mut new_outpoints);
2013                                                 if let Some(new_outputs) = new_outputs_option {
2014                                                         watch_outputs.push(new_outputs);
2015                                                 }
2016                                         }
2017                                 }
2018                         }
2019                         // While all commitment/HTLC-Success/HTLC-Timeout transactions have one input, HTLCs
2020                         // can also be resolved in a few other ways which can have more than one output. Thus,
2021                         // we call is_resolving_htlc_output here outside of the tx.input.len() == 1 check.
2022                         self.is_resolving_htlc_output(&tx, height, &logger);
2023
2024                         self.is_paying_spendable_output(&tx, height, &logger);
2025                 }
2026                 let should_broadcast = self.would_broadcast_at_height(height, &logger);
2027                 if should_broadcast {
2028                         claimable_outpoints.push(ClaimRequest { absolute_timelock: height, aggregable: false, outpoint: BitcoinOutPoint { txid: self.funding_info.0.txid.clone(), vout: self.funding_info.0.index as u32 }, witness_data: InputMaterial::Funding { funding_redeemscript: self.funding_redeemscript.clone() }});
2029                 }
2030                 if should_broadcast {
2031                         self.pending_monitor_events.push(MonitorEvent::CommitmentTxBroadcasted(self.funding_info.0));
2032                         let commitment_tx = self.onchain_tx_handler.get_fully_signed_holder_tx(&self.funding_redeemscript);
2033                         self.holder_tx_signed = true;
2034                         let (mut new_outpoints, _) = self.get_broadcasted_holder_claims(&self.current_holder_commitment_tx);
2035                         let new_outputs = self.get_broadcasted_holder_watch_outputs(&self.current_holder_commitment_tx, &commitment_tx);
2036                         if !new_outputs.is_empty() {
2037                                 watch_outputs.push((self.current_holder_commitment_tx.txid.clone(), new_outputs));
2038                         }
2039                         claimable_outpoints.append(&mut new_outpoints);
2040                 }
2041                 if let Some(events) = self.onchain_events_waiting_threshold_conf.remove(&height) {
2042                         for ev in events {
2043                                 match ev {
2044                                         OnchainEvent::HTLCUpdate { htlc_update } => {
2045                                                 log_trace!(logger, "HTLC {} failure update has got enough confirmations to be passed upstream", log_bytes!((htlc_update.1).0));
2046                                                 self.pending_monitor_events.push(MonitorEvent::HTLCEvent(HTLCUpdate {
2047                                                         payment_hash: htlc_update.1,
2048                                                         payment_preimage: None,
2049                                                         source: htlc_update.0,
2050                                                 }));
2051                                         },
2052                                         OnchainEvent::MaturingOutput { descriptor } => {
2053                                                 log_trace!(logger, "Descriptor {} has got enough confirmations to be passed upstream", log_spendable!(descriptor));
2054                                                 self.pending_events.push(Event::SpendableOutputs {
2055                                                         outputs: vec![descriptor]
2056                                                 });
2057                                         }
2058                                 }
2059                         }
2060                 }
2061
2062                 self.onchain_tx_handler.update_claims_view(&txn_matched, claimable_outpoints, Some(height), &&*broadcaster, &&*fee_estimator, &&*logger);
2063                 self.last_block_hash = block_hash;
2064
2065                 // Determine new outputs to watch by comparing against previously known outputs to watch,
2066                 // updating the latter in the process.
2067                 watch_outputs.retain(|&(ref txid, ref txouts)| {
2068                         let idx_and_scripts = txouts.iter().map(|o| (o.0, o.1.script_pubkey.clone())).collect();
2069                         self.outputs_to_watch.insert(txid.clone(), idx_and_scripts).is_none()
2070                 });
2071                 #[cfg(test)]
2072                 {
2073                         // If we see a transaction for which we registered outputs previously,
2074                         // make sure the registered scriptpubkey at the expected index match
2075                         // the actual transaction output one. We failed this case before #653.
2076                         for tx in &txn_matched {
2077                                 if let Some(outputs) = self.get_outputs_to_watch().get(&tx.txid()) {
2078                                         for idx_and_script in outputs.iter() {
2079                                                 assert!((idx_and_script.0 as usize) < tx.output.len());
2080                                                 assert_eq!(tx.output[idx_and_script.0 as usize].script_pubkey, idx_and_script.1);
2081                                         }
2082                                 }
2083                         }
2084                 }
2085                 watch_outputs
2086         }
2087
2088         pub fn block_disconnected<B: Deref, F: Deref, L: Deref>(&mut self, header: &BlockHeader, height: u32, broadcaster: B, fee_estimator: F, logger: L)
2089                 where B::Target: BroadcasterInterface,
2090                       F::Target: FeeEstimator,
2091                       L::Target: Logger,
2092         {
2093                 let block_hash = header.block_hash();
2094                 log_trace!(logger, "Block {} at height {} disconnected", block_hash, height);
2095
2096                 if let Some(_) = self.onchain_events_waiting_threshold_conf.remove(&(height + ANTI_REORG_DELAY - 1)) {
2097                         //We may discard:
2098                         //- htlc update there as failure-trigger tx (revoked commitment tx, non-revoked commitment tx, HTLC-timeout tx) has been disconnected
2099                         //- maturing spendable output has transaction paying us has been disconnected
2100                 }
2101
2102                 self.onchain_tx_handler.block_disconnected(height, broadcaster, fee_estimator, logger);
2103
2104                 self.last_block_hash = block_hash;
2105         }
2106
2107         /// Filters a block's `txdata` for transactions spending watched outputs or for any child
2108         /// transactions thereof.
2109         fn filter_block<'a>(&self, txdata: &TransactionData<'a>) -> Vec<&'a Transaction> {
2110                 let mut matched_txn = HashSet::new();
2111                 txdata.iter().filter(|&&(_, tx)| {
2112                         let mut matches = self.spends_watched_output(tx);
2113                         for input in tx.input.iter() {
2114                                 if matches { break; }
2115                                 if matched_txn.contains(&input.previous_output.txid) {
2116                                         matches = true;
2117                                 }
2118                         }
2119                         if matches {
2120                                 matched_txn.insert(tx.txid());
2121                         }
2122                         matches
2123                 }).map(|(_, tx)| *tx).collect()
2124         }
2125
2126         /// Checks if a given transaction spends any watched outputs.
2127         fn spends_watched_output(&self, tx: &Transaction) -> bool {
2128                 for input in tx.input.iter() {
2129                         if let Some(outputs) = self.get_outputs_to_watch().get(&input.previous_output.txid) {
2130                                 for (idx, _script_pubkey) in outputs.iter() {
2131                                         if *idx == input.previous_output.vout {
2132                                                 #[cfg(test)]
2133                                                 {
2134                                                         // If the expected script is a known type, check that the witness
2135                                                         // appears to be spending the correct type (ie that the match would
2136                                                         // actually succeed in BIP 158/159-style filters).
2137                                                         if _script_pubkey.is_v0_p2wsh() {
2138                                                                 assert_eq!(&bitcoin::Address::p2wsh(&Script::from(input.witness.last().unwrap().clone()), bitcoin::Network::Bitcoin).script_pubkey(), _script_pubkey);
2139                                                         } else if _script_pubkey.is_v0_p2wpkh() {
2140                                                                 assert_eq!(&bitcoin::Address::p2wpkh(&bitcoin::PublicKey::from_slice(&input.witness.last().unwrap()).unwrap(), bitcoin::Network::Bitcoin).unwrap().script_pubkey(), _script_pubkey);
2141                                                         } else { panic!(); }
2142                                                 }
2143                                                 return true;
2144                                         }
2145                                 }
2146                         }
2147                 }
2148
2149                 false
2150         }
2151
2152         fn would_broadcast_at_height<L: Deref>(&self, height: u32, logger: &L) -> bool where L::Target: Logger {
2153                 // We need to consider all HTLCs which are:
2154                 //  * in any unrevoked counterparty commitment transaction, as they could broadcast said
2155                 //    transactions and we'd end up in a race, or
2156                 //  * are in our latest holder commitment transaction, as this is the thing we will
2157                 //    broadcast if we go on-chain.
2158                 // Note that we consider HTLCs which were below dust threshold here - while they don't
2159                 // strictly imply that we need to fail the channel, we need to go ahead and fail them back
2160                 // to the source, and if we don't fail the channel we will have to ensure that the next
2161                 // updates that peer sends us are update_fails, failing the channel if not. It's probably
2162                 // easier to just fail the channel as this case should be rare enough anyway.
2163                 macro_rules! scan_commitment {
2164                         ($htlcs: expr, $holder_tx: expr) => {
2165                                 for ref htlc in $htlcs {
2166                                         // For inbound HTLCs which we know the preimage for, we have to ensure we hit the
2167                                         // chain with enough room to claim the HTLC without our counterparty being able to
2168                                         // time out the HTLC first.
2169                                         // For outbound HTLCs which our counterparty hasn't failed/claimed, our primary
2170                                         // concern is being able to claim the corresponding inbound HTLC (on another
2171                                         // channel) before it expires. In fact, we don't even really care if our
2172                                         // counterparty here claims such an outbound HTLC after it expired as long as we
2173                                         // can still claim the corresponding HTLC. Thus, to avoid needlessly hitting the
2174                                         // chain when our counterparty is waiting for expiration to off-chain fail an HTLC
2175                                         // we give ourselves a few blocks of headroom after expiration before going
2176                                         // on-chain for an expired HTLC.
2177                                         // Note that, to avoid a potential attack whereby a node delays claiming an HTLC
2178                                         // from us until we've reached the point where we go on-chain with the
2179                                         // corresponding inbound HTLC, we must ensure that outbound HTLCs go on chain at
2180                                         // least CLTV_CLAIM_BUFFER blocks prior to the inbound HTLC.
2181                                         //  aka outbound_cltv + LATENCY_GRACE_PERIOD_BLOCKS == height - CLTV_CLAIM_BUFFER
2182                                         //      inbound_cltv == height + CLTV_CLAIM_BUFFER
2183                                         //      outbound_cltv + LATENCY_GRACE_PERIOD_BLOCKS + CLTV_CLAIM_BUFFER <= inbound_cltv - CLTV_CLAIM_BUFFER
2184                                         //      LATENCY_GRACE_PERIOD_BLOCKS + 2*CLTV_CLAIM_BUFFER <= inbound_cltv - outbound_cltv
2185                                         //      CLTV_EXPIRY_DELTA <= inbound_cltv - outbound_cltv (by check in ChannelManager::decode_update_add_htlc_onion)
2186                                         //      LATENCY_GRACE_PERIOD_BLOCKS + 2*CLTV_CLAIM_BUFFER <= CLTV_EXPIRY_DELTA
2187                                         //  The final, above, condition is checked for statically in channelmanager
2188                                         //  with CHECK_CLTV_EXPIRY_SANITY_2.
2189                                         let htlc_outbound = $holder_tx == htlc.offered;
2190                                         if ( htlc_outbound && htlc.cltv_expiry + LATENCY_GRACE_PERIOD_BLOCKS <= height) ||
2191                                            (!htlc_outbound && htlc.cltv_expiry <= height + CLTV_CLAIM_BUFFER && self.payment_preimages.contains_key(&htlc.payment_hash)) {
2192                                                 log_info!(logger, "Force-closing channel due to {} HTLC timeout, HTLC expiry is {}", if htlc_outbound { "outbound" } else { "inbound "}, htlc.cltv_expiry);
2193                                                 return true;
2194                                         }
2195                                 }
2196                         }
2197                 }
2198
2199                 scan_commitment!(self.current_holder_commitment_tx.htlc_outputs.iter().map(|&(ref a, _, _)| a), true);
2200
2201                 if let Some(ref txid) = self.current_counterparty_commitment_txid {
2202                         if let Some(ref htlc_outputs) = self.counterparty_claimable_outpoints.get(txid) {
2203                                 scan_commitment!(htlc_outputs.iter().map(|&(ref a, _)| a), false);
2204                         }
2205                 }
2206                 if let Some(ref txid) = self.prev_counterparty_commitment_txid {
2207                         if let Some(ref htlc_outputs) = self.counterparty_claimable_outpoints.get(txid) {
2208                                 scan_commitment!(htlc_outputs.iter().map(|&(ref a, _)| a), false);
2209                         }
2210                 }
2211
2212                 false
2213         }
2214
2215         /// Check if any transaction broadcasted is resolving HTLC output by a success or timeout on a holder
2216         /// or counterparty commitment tx, if so send back the source, preimage if found and payment_hash of resolved HTLC
2217         fn is_resolving_htlc_output<L: Deref>(&mut self, tx: &Transaction, height: u32, logger: &L) where L::Target: Logger {
2218                 'outer_loop: for input in &tx.input {
2219                         let mut payment_data = None;
2220                         let revocation_sig_claim = (input.witness.len() == 3 && HTLCType::scriptlen_to_htlctype(input.witness[2].len()) == Some(HTLCType::OfferedHTLC) && input.witness[1].len() == 33)
2221                                 || (input.witness.len() == 3 && HTLCType::scriptlen_to_htlctype(input.witness[2].len()) == Some(HTLCType::AcceptedHTLC) && input.witness[1].len() == 33);
2222                         let accepted_preimage_claim = input.witness.len() == 5 && HTLCType::scriptlen_to_htlctype(input.witness[4].len()) == Some(HTLCType::AcceptedHTLC);
2223                         let offered_preimage_claim = input.witness.len() == 3 && HTLCType::scriptlen_to_htlctype(input.witness[2].len()) == Some(HTLCType::OfferedHTLC);
2224
2225                         macro_rules! log_claim {
2226                                 ($tx_info: expr, $holder_tx: expr, $htlc: expr, $source_avail: expr) => {
2227                                         // We found the output in question, but aren't failing it backwards
2228                                         // as we have no corresponding source and no valid counterparty commitment txid
2229                                         // to try a weak source binding with same-hash, same-value still-valid offered HTLC.
2230                                         // This implies either it is an inbound HTLC or an outbound HTLC on a revoked transaction.
2231                                         let outbound_htlc = $holder_tx == $htlc.offered;
2232                                         if ($holder_tx && revocation_sig_claim) ||
2233                                                         (outbound_htlc && !$source_avail && (accepted_preimage_claim || offered_preimage_claim)) {
2234                                                 log_error!(logger, "Input spending {} ({}:{}) in {} resolves {} HTLC with payment hash {} with {}!",
2235                                                         $tx_info, input.previous_output.txid, input.previous_output.vout, tx.txid(),
2236                                                         if outbound_htlc { "outbound" } else { "inbound" }, log_bytes!($htlc.payment_hash.0),
2237                                                         if revocation_sig_claim { "revocation sig" } else { "preimage claim after we'd passed the HTLC resolution back" });
2238                                         } else {
2239                                                 log_info!(logger, "Input spending {} ({}:{}) in {} resolves {} HTLC with payment hash {} with {}",
2240                                                         $tx_info, input.previous_output.txid, input.previous_output.vout, tx.txid(),
2241                                                         if outbound_htlc { "outbound" } else { "inbound" }, log_bytes!($htlc.payment_hash.0),
2242                                                         if revocation_sig_claim { "revocation sig" } else if accepted_preimage_claim || offered_preimage_claim { "preimage" } else { "timeout" });
2243                                         }
2244                                 }
2245                         }
2246
2247                         macro_rules! check_htlc_valid_counterparty {
2248                                 ($counterparty_txid: expr, $htlc_output: expr) => {
2249                                         if let Some(txid) = $counterparty_txid {
2250                                                 for &(ref pending_htlc, ref pending_source) in self.counterparty_claimable_outpoints.get(&txid).unwrap() {
2251                                                         if pending_htlc.payment_hash == $htlc_output.payment_hash && pending_htlc.amount_msat == $htlc_output.amount_msat {
2252                                                                 if let &Some(ref source) = pending_source {
2253                                                                         log_claim!("revoked counterparty commitment tx", false, pending_htlc, true);
2254                                                                         payment_data = Some(((**source).clone(), $htlc_output.payment_hash));
2255                                                                         break;
2256                                                                 }
2257                                                         }
2258                                                 }
2259                                         }
2260                                 }
2261                         }
2262
2263                         macro_rules! scan_commitment {
2264                                 ($htlcs: expr, $tx_info: expr, $holder_tx: expr) => {
2265                                         for (ref htlc_output, source_option) in $htlcs {
2266                                                 if Some(input.previous_output.vout) == htlc_output.transaction_output_index {
2267                                                         if let Some(ref source) = source_option {
2268                                                                 log_claim!($tx_info, $holder_tx, htlc_output, true);
2269                                                                 // We have a resolution of an HTLC either from one of our latest
2270                                                                 // holder commitment transactions or an unrevoked counterparty commitment
2271                                                                 // transaction. This implies we either learned a preimage, the HTLC
2272                                                                 // has timed out, or we screwed up. In any case, we should now
2273                                                                 // resolve the source HTLC with the original sender.
2274                                                                 payment_data = Some(((*source).clone(), htlc_output.payment_hash));
2275                                                         } else if !$holder_tx {
2276                                                                         check_htlc_valid_counterparty!(self.current_counterparty_commitment_txid, htlc_output);
2277                                                                 if payment_data.is_none() {
2278                                                                         check_htlc_valid_counterparty!(self.prev_counterparty_commitment_txid, htlc_output);
2279                                                                 }
2280                                                         }
2281                                                         if payment_data.is_none() {
2282                                                                 log_claim!($tx_info, $holder_tx, htlc_output, false);
2283                                                                 continue 'outer_loop;
2284                                                         }
2285                                                 }
2286                                         }
2287                                 }
2288                         }
2289
2290                         if input.previous_output.txid == self.current_holder_commitment_tx.txid {
2291                                 scan_commitment!(self.current_holder_commitment_tx.htlc_outputs.iter().map(|&(ref a, _, ref b)| (a, b.as_ref())),
2292                                         "our latest holder commitment tx", true);
2293                         }
2294                         if let Some(ref prev_holder_signed_commitment_tx) = self.prev_holder_signed_commitment_tx {
2295                                 if input.previous_output.txid == prev_holder_signed_commitment_tx.txid {
2296                                         scan_commitment!(prev_holder_signed_commitment_tx.htlc_outputs.iter().map(|&(ref a, _, ref b)| (a, b.as_ref())),
2297                                                 "our previous holder commitment tx", true);
2298                                 }
2299                         }
2300                         if let Some(ref htlc_outputs) = self.counterparty_claimable_outpoints.get(&input.previous_output.txid) {
2301                                 scan_commitment!(htlc_outputs.iter().map(|&(ref a, ref b)| (a, (b.as_ref().clone()).map(|boxed| &**boxed))),
2302                                         "counterparty commitment tx", false);
2303                         }
2304
2305                         // Check that scan_commitment, above, decided there is some source worth relaying an
2306                         // HTLC resolution backwards to and figure out whether we learned a preimage from it.
2307                         if let Some((source, payment_hash)) = payment_data {
2308                                 let mut payment_preimage = PaymentPreimage([0; 32]);
2309                                 if accepted_preimage_claim {
2310                                         if !self.pending_monitor_events.iter().any(
2311                                                 |update| if let &MonitorEvent::HTLCEvent(ref upd) = update { upd.source == source } else { false }) {
2312                                                 payment_preimage.0.copy_from_slice(&input.witness[3]);
2313                                                 self.pending_monitor_events.push(MonitorEvent::HTLCEvent(HTLCUpdate {
2314                                                         source,
2315                                                         payment_preimage: Some(payment_preimage),
2316                                                         payment_hash
2317                                                 }));
2318                                         }
2319                                 } else if offered_preimage_claim {
2320                                         if !self.pending_monitor_events.iter().any(
2321                                                 |update| if let &MonitorEvent::HTLCEvent(ref upd) = update {
2322                                                         upd.source == source
2323                                                 } else { false }) {
2324                                                 payment_preimage.0.copy_from_slice(&input.witness[1]);
2325                                                 self.pending_monitor_events.push(MonitorEvent::HTLCEvent(HTLCUpdate {
2326                                                         source,
2327                                                         payment_preimage: Some(payment_preimage),
2328                                                         payment_hash
2329                                                 }));
2330                                         }
2331                                 } else {
2332                                         log_info!(logger, "Failing HTLC with payment_hash {} timeout by a spend tx, waiting for confirmation (at height{})", log_bytes!(payment_hash.0), height + ANTI_REORG_DELAY - 1);
2333                                         match self.onchain_events_waiting_threshold_conf.entry(height + ANTI_REORG_DELAY - 1) {
2334                                                 hash_map::Entry::Occupied(mut entry) => {
2335                                                         let e = entry.get_mut();
2336                                                         e.retain(|ref event| {
2337                                                                 match **event {
2338                                                                         OnchainEvent::HTLCUpdate { ref htlc_update } => {
2339                                                                                 return htlc_update.0 != source
2340                                                                         },
2341                                                                         _ => true
2342                                                                 }
2343                                                         });
2344                                                         e.push(OnchainEvent::HTLCUpdate { htlc_update: (source, payment_hash)});
2345                                                 }
2346                                                 hash_map::Entry::Vacant(entry) => {
2347                                                         entry.insert(vec![OnchainEvent::HTLCUpdate { htlc_update: (source, payment_hash)}]);
2348                                                 }
2349                                         }
2350                                 }
2351                         }
2352                 }
2353         }
2354
2355         /// Check if any transaction broadcasted is paying fund back to some address we can assume to own
2356         fn is_paying_spendable_output<L: Deref>(&mut self, tx: &Transaction, height: u32, logger: &L) where L::Target: Logger {
2357                 let mut spendable_output = None;
2358                 for (i, outp) in tx.output.iter().enumerate() { // There is max one spendable output for any channel tx, including ones generated by us
2359                         if i > ::std::u16::MAX as usize {
2360                                 // While it is possible that an output exists on chain which is greater than the
2361                                 // 2^16th output in a given transaction, this is only possible if the output is not
2362                                 // in a lightning transaction and was instead placed there by some third party who
2363                                 // wishes to give us money for no reason.
2364                                 // Namely, any lightning transactions which we pre-sign will never have anywhere
2365                                 // near 2^16 outputs both because such transactions must have ~2^16 outputs who's
2366                                 // scripts are not longer than one byte in length and because they are inherently
2367                                 // non-standard due to their size.
2368                                 // Thus, it is completely safe to ignore such outputs, and while it may result in
2369                                 // us ignoring non-lightning fund to us, that is only possible if someone fills
2370                                 // nearly a full block with garbage just to hit this case.
2371                                 continue;
2372                         }
2373                         if outp.script_pubkey == self.destination_script {
2374                                 spendable_output =  Some(SpendableOutputDescriptor::StaticOutput {
2375                                         outpoint: OutPoint { txid: tx.txid(), index: i as u16 },
2376                                         output: outp.clone(),
2377                                 });
2378                                 break;
2379                         } else if let Some(ref broadcasted_holder_revokable_script) = self.broadcasted_holder_revokable_script {
2380                                 if broadcasted_holder_revokable_script.0 == outp.script_pubkey {
2381                                         spendable_output =  Some(SpendableOutputDescriptor::DelayedPaymentOutput(DelayedPaymentOutputDescriptor {
2382                                                 outpoint: OutPoint { txid: tx.txid(), index: i as u16 },
2383                                                 per_commitment_point: broadcasted_holder_revokable_script.1,
2384                                                 to_self_delay: self.on_holder_tx_csv,
2385                                                 output: outp.clone(),
2386                                                 revocation_pubkey: broadcasted_holder_revokable_script.2.clone(),
2387                                                 channel_keys_id: self.channel_keys_id,
2388                                                 channel_value_satoshis: self.channel_value_satoshis,
2389                                         }));
2390                                         break;
2391                                 }
2392                         } else if self.counterparty_payment_script == outp.script_pubkey {
2393                                 spendable_output = Some(SpendableOutputDescriptor::StaticPaymentOutput(StaticPaymentOutputDescriptor {
2394                                         outpoint: OutPoint { txid: tx.txid(), index: i as u16 },
2395                                         output: outp.clone(),
2396                                         channel_keys_id: self.channel_keys_id,
2397                                         channel_value_satoshis: self.channel_value_satoshis,
2398                                 }));
2399                                 break;
2400                         } else if outp.script_pubkey == self.shutdown_script {
2401                                 spendable_output = Some(SpendableOutputDescriptor::StaticOutput {
2402                                         outpoint: OutPoint { txid: tx.txid(), index: i as u16 },
2403                                         output: outp.clone(),
2404                                 });
2405                         }
2406                 }
2407                 if let Some(spendable_output) = spendable_output {
2408                         log_trace!(logger, "Maturing {} until {}", log_spendable!(spendable_output), height + ANTI_REORG_DELAY - 1);
2409                         match self.onchain_events_waiting_threshold_conf.entry(height + ANTI_REORG_DELAY - 1) {
2410                                 hash_map::Entry::Occupied(mut entry) => {
2411                                         let e = entry.get_mut();
2412                                         e.push(OnchainEvent::MaturingOutput { descriptor: spendable_output });
2413                                 }
2414                                 hash_map::Entry::Vacant(entry) => {
2415                                         entry.insert(vec![OnchainEvent::MaturingOutput { descriptor: spendable_output }]);
2416                                 }
2417                         }
2418                 }
2419         }
2420 }
2421
2422 /// `Persist` defines behavior for persisting channel monitors: this could mean
2423 /// writing once to disk, and/or uploading to one or more backup services.
2424 ///
2425 /// Note that for every new monitor, you **must** persist the new `ChannelMonitor`
2426 /// to disk/backups. And, on every update, you **must** persist either the
2427 /// `ChannelMonitorUpdate` or the updated monitor itself. Otherwise, there is risk
2428 /// of situations such as revoking a transaction, then crashing before this
2429 /// revocation can be persisted, then unintentionally broadcasting a revoked
2430 /// transaction and losing money. This is a risk because previous channel states
2431 /// are toxic, so it's important that whatever channel state is persisted is
2432 /// kept up-to-date.
2433 pub trait Persist<ChannelSigner: Sign>: Send + Sync {
2434         /// Persist a new channel's data. The data can be stored any way you want, but
2435         /// the identifier provided by Rust-Lightning is the channel's outpoint (and
2436         /// it is up to you to maintain a correct mapping between the outpoint and the
2437         /// stored channel data). Note that you **must** persist every new monitor to
2438         /// disk. See the `Persist` trait documentation for more details.
2439         ///
2440         /// See [`ChannelMonitor::serialize_for_disk`] for writing out a `ChannelMonitor`,
2441         /// and [`ChannelMonitorUpdateErr`] for requirements when returning errors.
2442         ///
2443         /// [`ChannelMonitor::serialize_for_disk`]: struct.ChannelMonitor.html#method.serialize_for_disk
2444         /// [`ChannelMonitorUpdateErr`]: enum.ChannelMonitorUpdateErr.html
2445         fn persist_new_channel(&self, id: OutPoint, data: &ChannelMonitor<ChannelSigner>) -> Result<(), ChannelMonitorUpdateErr>;
2446
2447         /// Update one channel's data. The provided `ChannelMonitor` has already
2448         /// applied the given update.
2449         ///
2450         /// Note that on every update, you **must** persist either the
2451         /// `ChannelMonitorUpdate` or the updated monitor itself to disk/backups. See
2452         /// the `Persist` trait documentation for more details.
2453         ///
2454         /// If an implementer chooses to persist the updates only, they need to make
2455         /// sure that all the updates are applied to the `ChannelMonitors` *before*
2456         /// the set of channel monitors is given to the `ChannelManager`
2457         /// deserialization routine. See [`ChannelMonitor::update_monitor`] for
2458         /// applying a monitor update to a monitor. If full `ChannelMonitors` are
2459         /// persisted, then there is no need to persist individual updates.
2460         ///
2461         /// Note that there could be a performance tradeoff between persisting complete
2462         /// channel monitors on every update vs. persisting only updates and applying
2463         /// them in batches. The size of each monitor grows `O(number of state updates)`
2464         /// whereas updates are small and `O(1)`.
2465         ///
2466         /// See [`ChannelMonitor::serialize_for_disk`] for writing out a `ChannelMonitor`,
2467         /// [`ChannelMonitorUpdate::write`] for writing out an update, and
2468         /// [`ChannelMonitorUpdateErr`] for requirements when returning errors.
2469         ///
2470         /// [`ChannelMonitor::update_monitor`]: struct.ChannelMonitor.html#impl-1
2471         /// [`ChannelMonitor::serialize_for_disk`]: struct.ChannelMonitor.html#method.serialize_for_disk
2472         /// [`ChannelMonitorUpdate::write`]: struct.ChannelMonitorUpdate.html#method.write
2473         /// [`ChannelMonitorUpdateErr`]: enum.ChannelMonitorUpdateErr.html
2474         fn update_persisted_channel(&self, id: OutPoint, update: &ChannelMonitorUpdate, data: &ChannelMonitor<ChannelSigner>) -> Result<(), ChannelMonitorUpdateErr>;
2475 }
2476
2477 impl<Signer: Sign, T: Deref, F: Deref, L: Deref> chain::Listen for (ChannelMonitor<Signer>, T, F, L)
2478 where
2479         T::Target: BroadcasterInterface,
2480         F::Target: FeeEstimator,
2481         L::Target: Logger,
2482 {
2483         fn block_connected(&self, block: &Block, height: u32) {
2484                 let txdata: Vec<_> = block.txdata.iter().enumerate().collect();
2485                 self.0.block_connected(&block.header, &txdata, height, &*self.1, &*self.2, &*self.3);
2486         }
2487
2488         fn block_disconnected(&self, header: &BlockHeader, height: u32) {
2489                 self.0.block_disconnected(header, height, &*self.1, &*self.2, &*self.3);
2490         }
2491 }
2492
2493 const MAX_ALLOC_SIZE: usize = 64*1024;
2494
2495 impl<'a, Signer: Sign, K: KeysInterface<Signer = Signer>> ReadableArgs<&'a K>
2496                 for (BlockHash, ChannelMonitor<Signer>) {
2497         fn read<R: ::std::io::Read>(reader: &mut R, keys_manager: &'a K) -> Result<Self, DecodeError> {
2498                 macro_rules! unwrap_obj {
2499                         ($key: expr) => {
2500                                 match $key {
2501                                         Ok(res) => res,
2502                                         Err(_) => return Err(DecodeError::InvalidValue),
2503                                 }
2504                         }
2505                 }
2506
2507                 let _ver: u8 = Readable::read(reader)?;
2508                 let min_ver: u8 = Readable::read(reader)?;
2509                 if min_ver > SERIALIZATION_VERSION {
2510                         return Err(DecodeError::UnknownVersion);
2511                 }
2512
2513                 let latest_update_id: u64 = Readable::read(reader)?;
2514                 let commitment_transaction_number_obscure_factor = <U48 as Readable>::read(reader)?.0;
2515
2516                 let destination_script = Readable::read(reader)?;
2517                 let broadcasted_holder_revokable_script = match <u8 as Readable>::read(reader)? {
2518                         0 => {
2519                                 let revokable_address = Readable::read(reader)?;
2520                                 let per_commitment_point = Readable::read(reader)?;
2521                                 let revokable_script = Readable::read(reader)?;
2522                                 Some((revokable_address, per_commitment_point, revokable_script))
2523                         },
2524                         1 => { None },
2525                         _ => return Err(DecodeError::InvalidValue),
2526                 };
2527                 let counterparty_payment_script = Readable::read(reader)?;
2528                 let shutdown_script = Readable::read(reader)?;
2529
2530                 let channel_keys_id = Readable::read(reader)?;
2531                 let holder_revocation_basepoint = Readable::read(reader)?;
2532                 // Technically this can fail and serialize fail a round-trip, but only for serialization of
2533                 // barely-init'd ChannelMonitors that we can't do anything with.
2534                 let outpoint = OutPoint {
2535                         txid: Readable::read(reader)?,
2536                         index: Readable::read(reader)?,
2537                 };
2538                 let funding_info = (outpoint, Readable::read(reader)?);
2539                 let current_counterparty_commitment_txid = Readable::read(reader)?;
2540                 let prev_counterparty_commitment_txid = Readable::read(reader)?;
2541
2542                 let counterparty_tx_cache = Readable::read(reader)?;
2543                 let funding_redeemscript = Readable::read(reader)?;
2544                 let channel_value_satoshis = Readable::read(reader)?;
2545
2546                 let their_cur_revocation_points = {
2547                         let first_idx = <U48 as Readable>::read(reader)?.0;
2548                         if first_idx == 0 {
2549                                 None
2550                         } else {
2551                                 let first_point = Readable::read(reader)?;
2552                                 let second_point_slice: [u8; 33] = Readable::read(reader)?;
2553                                 if second_point_slice[0..32] == [0; 32] && second_point_slice[32] == 0 {
2554                                         Some((first_idx, first_point, None))
2555                                 } else {
2556                                         Some((first_idx, first_point, Some(unwrap_obj!(PublicKey::from_slice(&second_point_slice)))))
2557                                 }
2558                         }
2559                 };
2560
2561                 let on_holder_tx_csv: u16 = Readable::read(reader)?;
2562
2563                 let commitment_secrets = Readable::read(reader)?;
2564
2565                 macro_rules! read_htlc_in_commitment {
2566                         () => {
2567                                 {
2568                                         let offered: bool = Readable::read(reader)?;
2569                                         let amount_msat: u64 = Readable::read(reader)?;
2570                                         let cltv_expiry: u32 = Readable::read(reader)?;
2571                                         let payment_hash: PaymentHash = Readable::read(reader)?;
2572                                         let transaction_output_index: Option<u32> = Readable::read(reader)?;
2573
2574                                         HTLCOutputInCommitment {
2575                                                 offered, amount_msat, cltv_expiry, payment_hash, transaction_output_index
2576                                         }
2577                                 }
2578                         }
2579                 }
2580
2581                 let counterparty_claimable_outpoints_len: u64 = Readable::read(reader)?;
2582                 let mut counterparty_claimable_outpoints = HashMap::with_capacity(cmp::min(counterparty_claimable_outpoints_len as usize, MAX_ALLOC_SIZE / 64));
2583                 for _ in 0..counterparty_claimable_outpoints_len {
2584                         let txid: Txid = Readable::read(reader)?;
2585                         let htlcs_count: u64 = Readable::read(reader)?;
2586                         let mut htlcs = Vec::with_capacity(cmp::min(htlcs_count as usize, MAX_ALLOC_SIZE / 32));
2587                         for _ in 0..htlcs_count {
2588                                 htlcs.push((read_htlc_in_commitment!(), <Option<HTLCSource> as Readable>::read(reader)?.map(|o: HTLCSource| Box::new(o))));
2589                         }
2590                         if let Some(_) = counterparty_claimable_outpoints.insert(txid, htlcs) {
2591                                 return Err(DecodeError::InvalidValue);
2592                         }
2593                 }
2594
2595                 let counterparty_commitment_txn_on_chain_len: u64 = Readable::read(reader)?;
2596                 let mut counterparty_commitment_txn_on_chain = HashMap::with_capacity(cmp::min(counterparty_commitment_txn_on_chain_len as usize, MAX_ALLOC_SIZE / 32));
2597                 for _ in 0..counterparty_commitment_txn_on_chain_len {
2598                         let txid: Txid = Readable::read(reader)?;
2599                         let commitment_number = <U48 as Readable>::read(reader)?.0;
2600                         if let Some(_) = counterparty_commitment_txn_on_chain.insert(txid, commitment_number) {
2601                                 return Err(DecodeError::InvalidValue);
2602                         }
2603                 }
2604
2605                 let counterparty_hash_commitment_number_len: u64 = Readable::read(reader)?;
2606                 let mut counterparty_hash_commitment_number = HashMap::with_capacity(cmp::min(counterparty_hash_commitment_number_len as usize, MAX_ALLOC_SIZE / 32));
2607                 for _ in 0..counterparty_hash_commitment_number_len {
2608                         let payment_hash: PaymentHash = Readable::read(reader)?;
2609                         let commitment_number = <U48 as Readable>::read(reader)?.0;
2610                         if let Some(_) = counterparty_hash_commitment_number.insert(payment_hash, commitment_number) {
2611                                 return Err(DecodeError::InvalidValue);
2612                         }
2613                 }
2614
2615                 macro_rules! read_holder_tx {
2616                         () => {
2617                                 {
2618                                         let txid = Readable::read(reader)?;
2619                                         let revocation_key = Readable::read(reader)?;
2620                                         let a_htlc_key = Readable::read(reader)?;
2621                                         let b_htlc_key = Readable::read(reader)?;
2622                                         let delayed_payment_key = Readable::read(reader)?;
2623                                         let per_commitment_point = Readable::read(reader)?;
2624                                         let feerate_per_kw: u32 = Readable::read(reader)?;
2625
2626                                         let htlcs_len: u64 = Readable::read(reader)?;
2627                                         let mut htlcs = Vec::with_capacity(cmp::min(htlcs_len as usize, MAX_ALLOC_SIZE / 128));
2628                                         for _ in 0..htlcs_len {
2629                                                 let htlc = read_htlc_in_commitment!();
2630                                                 let sigs = match <u8 as Readable>::read(reader)? {
2631                                                         0 => None,
2632                                                         1 => Some(Readable::read(reader)?),
2633                                                         _ => return Err(DecodeError::InvalidValue),
2634                                                 };
2635                                                 htlcs.push((htlc, sigs, Readable::read(reader)?));
2636                                         }
2637
2638                                         HolderSignedTx {
2639                                                 txid,
2640                                                 revocation_key, a_htlc_key, b_htlc_key, delayed_payment_key, per_commitment_point, feerate_per_kw,
2641                                                 htlc_outputs: htlcs
2642                                         }
2643                                 }
2644                         }
2645                 }
2646
2647                 let prev_holder_signed_commitment_tx = match <u8 as Readable>::read(reader)? {
2648                         0 => None,
2649                         1 => {
2650                                 Some(read_holder_tx!())
2651                         },
2652                         _ => return Err(DecodeError::InvalidValue),
2653                 };
2654                 let current_holder_commitment_tx = read_holder_tx!();
2655
2656                 let current_counterparty_commitment_number = <U48 as Readable>::read(reader)?.0;
2657                 let current_holder_commitment_number = <U48 as Readable>::read(reader)?.0;
2658
2659                 let payment_preimages_len: u64 = Readable::read(reader)?;
2660                 let mut payment_preimages = HashMap::with_capacity(cmp::min(payment_preimages_len as usize, MAX_ALLOC_SIZE / 32));
2661                 for _ in 0..payment_preimages_len {
2662                         let preimage: PaymentPreimage = Readable::read(reader)?;
2663                         let hash = PaymentHash(Sha256::hash(&preimage.0[..]).into_inner());
2664                         if let Some(_) = payment_preimages.insert(hash, preimage) {
2665                                 return Err(DecodeError::InvalidValue);
2666                         }
2667                 }
2668
2669                 let pending_monitor_events_len: u64 = Readable::read(reader)?;
2670                 let mut pending_monitor_events = Vec::with_capacity(cmp::min(pending_monitor_events_len as usize, MAX_ALLOC_SIZE / (32 + 8*3)));
2671                 for _ in 0..pending_monitor_events_len {
2672                         let ev = match <u8 as Readable>::read(reader)? {
2673                                 0 => MonitorEvent::HTLCEvent(Readable::read(reader)?),
2674                                 1 => MonitorEvent::CommitmentTxBroadcasted(funding_info.0),
2675                                 _ => return Err(DecodeError::InvalidValue)
2676                         };
2677                         pending_monitor_events.push(ev);
2678                 }
2679
2680                 let pending_events_len: u64 = Readable::read(reader)?;
2681                 let mut pending_events = Vec::with_capacity(cmp::min(pending_events_len as usize, MAX_ALLOC_SIZE / mem::size_of::<Event>()));
2682                 for _ in 0..pending_events_len {
2683                         if let Some(event) = MaybeReadable::read(reader)? {
2684                                 pending_events.push(event);
2685                         }
2686                 }
2687
2688                 let last_block_hash: BlockHash = Readable::read(reader)?;
2689
2690                 let waiting_threshold_conf_len: u64 = Readable::read(reader)?;
2691                 let mut onchain_events_waiting_threshold_conf = HashMap::with_capacity(cmp::min(waiting_threshold_conf_len as usize, MAX_ALLOC_SIZE / 128));
2692                 for _ in 0..waiting_threshold_conf_len {
2693                         let height_target = Readable::read(reader)?;
2694                         let events_len: u64 = Readable::read(reader)?;
2695                         let mut events = Vec::with_capacity(cmp::min(events_len as usize, MAX_ALLOC_SIZE / 128));
2696                         for _ in 0..events_len {
2697                                 let ev = match <u8 as Readable>::read(reader)? {
2698                                         0 => {
2699                                                 let htlc_source = Readable::read(reader)?;
2700                                                 let hash = Readable::read(reader)?;
2701                                                 OnchainEvent::HTLCUpdate {
2702                                                         htlc_update: (htlc_source, hash)
2703                                                 }
2704                                         },
2705                                         1 => {
2706                                                 let descriptor = Readable::read(reader)?;
2707                                                 OnchainEvent::MaturingOutput {
2708                                                         descriptor
2709                                                 }
2710                                         },
2711                                         _ => return Err(DecodeError::InvalidValue),
2712                                 };
2713                                 events.push(ev);
2714                         }
2715                         onchain_events_waiting_threshold_conf.insert(height_target, events);
2716                 }
2717
2718                 let outputs_to_watch_len: u64 = Readable::read(reader)?;
2719                 let mut outputs_to_watch = HashMap::with_capacity(cmp::min(outputs_to_watch_len as usize, MAX_ALLOC_SIZE / (mem::size_of::<Txid>() + mem::size_of::<u32>() + mem::size_of::<Vec<Script>>())));
2720                 for _ in 0..outputs_to_watch_len {
2721                         let txid = Readable::read(reader)?;
2722                         let outputs_len: u64 = Readable::read(reader)?;
2723                         let mut outputs = Vec::with_capacity(cmp::min(outputs_len as usize, MAX_ALLOC_SIZE / (mem::size_of::<u32>() + mem::size_of::<Script>())));
2724                         for _ in 0..outputs_len {
2725                                 outputs.push((Readable::read(reader)?, Readable::read(reader)?));
2726                         }
2727                         if let Some(_) = outputs_to_watch.insert(txid, outputs) {
2728                                 return Err(DecodeError::InvalidValue);
2729                         }
2730                 }
2731                 let onchain_tx_handler = ReadableArgs::read(reader, keys_manager)?;
2732
2733                 let lockdown_from_offchain = Readable::read(reader)?;
2734                 let holder_tx_signed = Readable::read(reader)?;
2735
2736                 let mut secp_ctx = Secp256k1::new();
2737                 secp_ctx.seeded_randomize(&keys_manager.get_secure_random_bytes());
2738
2739                 Ok((last_block_hash.clone(), ChannelMonitor {
2740                         inner: Mutex::new(ChannelMonitorImpl {
2741                                 latest_update_id,
2742                                 commitment_transaction_number_obscure_factor,
2743
2744                                 destination_script,
2745                                 broadcasted_holder_revokable_script,
2746                                 counterparty_payment_script,
2747                                 shutdown_script,
2748
2749                                 channel_keys_id,
2750                                 holder_revocation_basepoint,
2751                                 funding_info,
2752                                 current_counterparty_commitment_txid,
2753                                 prev_counterparty_commitment_txid,
2754
2755                                 counterparty_tx_cache,
2756                                 funding_redeemscript,
2757                                 channel_value_satoshis,
2758                                 their_cur_revocation_points,
2759
2760                                 on_holder_tx_csv,
2761
2762                                 commitment_secrets,
2763                                 counterparty_claimable_outpoints,
2764                                 counterparty_commitment_txn_on_chain,
2765                                 counterparty_hash_commitment_number,
2766
2767                                 prev_holder_signed_commitment_tx,
2768                                 current_holder_commitment_tx,
2769                                 current_counterparty_commitment_number,
2770                                 current_holder_commitment_number,
2771
2772                                 payment_preimages,
2773                                 pending_monitor_events,
2774                                 pending_events,
2775
2776                                 onchain_events_waiting_threshold_conf,
2777                                 outputs_to_watch,
2778
2779                                 onchain_tx_handler,
2780
2781                                 lockdown_from_offchain,
2782                                 holder_tx_signed,
2783
2784                                 last_block_hash,
2785                                 secp_ctx,
2786                         }),
2787                 }))
2788         }
2789 }
2790
2791 #[cfg(test)]
2792 mod tests {
2793         use bitcoin::blockdata::constants::genesis_block;
2794         use bitcoin::blockdata::script::{Script, Builder};
2795         use bitcoin::blockdata::opcodes;
2796         use bitcoin::blockdata::transaction::{Transaction, TxIn, TxOut, SigHashType};
2797         use bitcoin::blockdata::transaction::OutPoint as BitcoinOutPoint;
2798         use bitcoin::util::bip143;
2799         use bitcoin::hashes::Hash;
2800         use bitcoin::hashes::sha256::Hash as Sha256;
2801         use bitcoin::hashes::hex::FromHex;
2802         use bitcoin::hash_types::Txid;
2803         use bitcoin::network::constants::Network;
2804         use hex;
2805         use chain::channelmonitor::ChannelMonitor;
2806         use chain::transaction::OutPoint;
2807         use ln::channelmanager::{PaymentPreimage, PaymentHash};
2808         use ln::onchaintx::{OnchainTxHandler, InputDescriptors};
2809         use ln::chan_utils;
2810         use ln::chan_utils::{HTLCOutputInCommitment, ChannelPublicKeys, ChannelTransactionParameters, HolderCommitmentTransaction, CounterpartyChannelTransactionParameters};
2811         use util::test_utils::{TestLogger, TestBroadcaster, TestFeeEstimator};
2812         use bitcoin::secp256k1::key::{SecretKey,PublicKey};
2813         use bitcoin::secp256k1::Secp256k1;
2814         use std::sync::{Arc, Mutex};
2815         use chain::keysinterface::InMemorySigner;
2816
2817         #[test]
2818         fn test_prune_preimages() {
2819                 let secp_ctx = Secp256k1::new();
2820                 let logger = Arc::new(TestLogger::new());
2821                 let broadcaster = Arc::new(TestBroadcaster{txn_broadcasted: Mutex::new(Vec::new())});
2822                 let fee_estimator = Arc::new(TestFeeEstimator { sat_per_kw: 253 });
2823
2824                 let dummy_key = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
2825                 let dummy_tx = Transaction { version: 0, lock_time: 0, input: Vec::new(), output: Vec::new() };
2826
2827                 let mut preimages = Vec::new();
2828                 {
2829                         for i in 0..20 {
2830                                 let preimage = PaymentPreimage([i; 32]);
2831                                 let hash = PaymentHash(Sha256::hash(&preimage.0[..]).into_inner());
2832                                 preimages.push((preimage, hash));
2833                         }
2834                 }
2835
2836                 macro_rules! preimages_slice_to_htlc_outputs {
2837                         ($preimages_slice: expr) => {
2838                                 {
2839                                         let mut res = Vec::new();
2840                                         for (idx, preimage) in $preimages_slice.iter().enumerate() {
2841                                                 res.push((HTLCOutputInCommitment {
2842                                                         offered: true,
2843                                                         amount_msat: 0,
2844                                                         cltv_expiry: 0,
2845                                                         payment_hash: preimage.1.clone(),
2846                                                         transaction_output_index: Some(idx as u32),
2847                                                 }, None));
2848                                         }
2849                                         res
2850                                 }
2851                         }
2852                 }
2853                 macro_rules! preimages_to_holder_htlcs {
2854                         ($preimages_slice: expr) => {
2855                                 {
2856                                         let mut inp = preimages_slice_to_htlc_outputs!($preimages_slice);
2857                                         let res: Vec<_> = inp.drain(..).map(|e| { (e.0, None, e.1) }).collect();
2858                                         res
2859                                 }
2860                         }
2861                 }
2862
2863                 macro_rules! test_preimages_exist {
2864                         ($preimages_slice: expr, $monitor: expr) => {
2865                                 for preimage in $preimages_slice {
2866                                         assert!($monitor.inner.lock().unwrap().payment_preimages.contains_key(&preimage.1));
2867                                 }
2868                         }
2869                 }
2870
2871                 let keys = InMemorySigner::new(
2872                         &secp_ctx,
2873                         SecretKey::from_slice(&[41; 32]).unwrap(),
2874                         SecretKey::from_slice(&[41; 32]).unwrap(),
2875                         SecretKey::from_slice(&[41; 32]).unwrap(),
2876                         SecretKey::from_slice(&[41; 32]).unwrap(),
2877                         SecretKey::from_slice(&[41; 32]).unwrap(),
2878                         [41; 32],
2879                         0,
2880                         [0; 32]
2881                 );
2882
2883                 let counterparty_pubkeys = ChannelPublicKeys {
2884                         funding_pubkey: PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[44; 32]).unwrap()),
2885                         revocation_basepoint: PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[45; 32]).unwrap()),
2886                         payment_point: PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[46; 32]).unwrap()),
2887                         delayed_payment_basepoint: PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[47; 32]).unwrap()),
2888                         htlc_basepoint: PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[48; 32]).unwrap())
2889                 };
2890                 let funding_outpoint = OutPoint { txid: Default::default(), index: u16::max_value() };
2891                 let channel_parameters = ChannelTransactionParameters {
2892                         holder_pubkeys: keys.holder_channel_pubkeys.clone(),
2893                         holder_selected_contest_delay: 66,
2894                         is_outbound_from_holder: true,
2895                         counterparty_parameters: Some(CounterpartyChannelTransactionParameters {
2896                                 pubkeys: counterparty_pubkeys,
2897                                 selected_contest_delay: 67,
2898                         }),
2899                         funding_outpoint: Some(funding_outpoint),
2900                 };
2901                 // Prune with one old state and a holder commitment tx holding a few overlaps with the
2902                 // old state.
2903                 let last_block_hash = genesis_block(Network::Testnet).block_hash();
2904                 let monitor = ChannelMonitor::new(Secp256k1::new(), keys,
2905                                                   &PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap()), 0, &Script::new(),
2906                                                   (OutPoint { txid: Txid::from_slice(&[43; 32]).unwrap(), index: 0 }, Script::new()),
2907                                                   &channel_parameters,
2908                                                   Script::new(), 46, 0,
2909                                                   HolderCommitmentTransaction::dummy(), last_block_hash);
2910
2911                 monitor.provide_latest_holder_commitment_tx(HolderCommitmentTransaction::dummy(), preimages_to_holder_htlcs!(preimages[0..10])).unwrap();
2912                 let dummy_txid = dummy_tx.txid();
2913                 monitor.provide_latest_counterparty_commitment_tx(dummy_txid, preimages_slice_to_htlc_outputs!(preimages[5..15]), 281474976710655, dummy_key, &logger);
2914                 monitor.provide_latest_counterparty_commitment_tx(dummy_txid, preimages_slice_to_htlc_outputs!(preimages[15..20]), 281474976710654, dummy_key, &logger);
2915                 monitor.provide_latest_counterparty_commitment_tx(dummy_txid, preimages_slice_to_htlc_outputs!(preimages[17..20]), 281474976710653, dummy_key, &logger);
2916                 monitor.provide_latest_counterparty_commitment_tx(dummy_txid, preimages_slice_to_htlc_outputs!(preimages[18..20]), 281474976710652, dummy_key, &logger);
2917                 for &(ref preimage, ref hash) in preimages.iter() {
2918                         monitor.provide_payment_preimage(hash, preimage, &broadcaster, &fee_estimator, &logger);
2919                 }
2920
2921                 // Now provide a secret, pruning preimages 10-15
2922                 let mut secret = [0; 32];
2923                 secret[0..32].clone_from_slice(&hex::decode("7cc854b54e3e0dcdb010d7a3fee464a9687be6e8db3be6854c475621e007a5dc").unwrap());
2924                 monitor.provide_secret(281474976710655, secret.clone()).unwrap();
2925                 assert_eq!(monitor.inner.lock().unwrap().payment_preimages.len(), 15);
2926                 test_preimages_exist!(&preimages[0..10], monitor);
2927                 test_preimages_exist!(&preimages[15..20], monitor);
2928
2929                 // Now provide a further secret, pruning preimages 15-17
2930                 secret[0..32].clone_from_slice(&hex::decode("c7518c8ae4660ed02894df8976fa1a3659c1a8b4b5bec0c4b872abeba4cb8964").unwrap());
2931                 monitor.provide_secret(281474976710654, secret.clone()).unwrap();
2932                 assert_eq!(monitor.inner.lock().unwrap().payment_preimages.len(), 13);
2933                 test_preimages_exist!(&preimages[0..10], monitor);
2934                 test_preimages_exist!(&preimages[17..20], monitor);
2935
2936                 // Now update holder commitment tx info, pruning only element 18 as we still care about the
2937                 // previous commitment tx's preimages too
2938                 monitor.provide_latest_holder_commitment_tx(HolderCommitmentTransaction::dummy(), preimages_to_holder_htlcs!(preimages[0..5])).unwrap();
2939                 secret[0..32].clone_from_slice(&hex::decode("2273e227a5b7449b6e70f1fb4652864038b1cbf9cd7c043a7d6456b7fc275ad8").unwrap());
2940                 monitor.provide_secret(281474976710653, secret.clone()).unwrap();
2941                 assert_eq!(monitor.inner.lock().unwrap().payment_preimages.len(), 12);
2942                 test_preimages_exist!(&preimages[0..10], monitor);
2943                 test_preimages_exist!(&preimages[18..20], monitor);
2944
2945                 // But if we do it again, we'll prune 5-10
2946                 monitor.provide_latest_holder_commitment_tx(HolderCommitmentTransaction::dummy(), preimages_to_holder_htlcs!(preimages[0..3])).unwrap();
2947                 secret[0..32].clone_from_slice(&hex::decode("27cddaa5624534cb6cb9d7da077cf2b22ab21e9b506fd4998a51d54502e99116").unwrap());
2948                 monitor.provide_secret(281474976710652, secret.clone()).unwrap();
2949                 assert_eq!(monitor.inner.lock().unwrap().payment_preimages.len(), 5);
2950                 test_preimages_exist!(&preimages[0..5], monitor);
2951         }
2952
2953         #[test]
2954         fn test_claim_txn_weight_computation() {
2955                 // We test Claim txn weight, knowing that we want expected weigth and
2956                 // not actual case to avoid sigs and time-lock delays hell variances.
2957
2958                 let secp_ctx = Secp256k1::new();
2959                 let privkey = SecretKey::from_slice(&hex::decode("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
2960                 let pubkey = PublicKey::from_secret_key(&secp_ctx, &privkey);
2961                 let mut sum_actual_sigs = 0;
2962
2963                 macro_rules! sign_input {
2964                         ($sighash_parts: expr, $idx: expr, $amount: expr, $input_type: expr, $sum_actual_sigs: expr) => {
2965                                 let htlc = HTLCOutputInCommitment {
2966                                         offered: if *$input_type == InputDescriptors::RevokedOfferedHTLC || *$input_type == InputDescriptors::OfferedHTLC { true } else { false },
2967                                         amount_msat: 0,
2968                                         cltv_expiry: 2 << 16,
2969                                         payment_hash: PaymentHash([1; 32]),
2970                                         transaction_output_index: Some($idx as u32),
2971                                 };
2972                                 let redeem_script = if *$input_type == InputDescriptors::RevokedOutput { chan_utils::get_revokeable_redeemscript(&pubkey, 256, &pubkey) } else { chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, &pubkey, &pubkey, &pubkey) };
2973                                 let sighash = hash_to_message!(&$sighash_parts.signature_hash($idx, &redeem_script, $amount, SigHashType::All)[..]);
2974                                 let sig = secp_ctx.sign(&sighash, &privkey);
2975                                 $sighash_parts.access_witness($idx).push(sig.serialize_der().to_vec());
2976                                 $sighash_parts.access_witness($idx)[0].push(SigHashType::All as u8);
2977                                 sum_actual_sigs += $sighash_parts.access_witness($idx)[0].len();
2978                                 if *$input_type == InputDescriptors::RevokedOutput {
2979                                         $sighash_parts.access_witness($idx).push(vec!(1));
2980                                 } else if *$input_type == InputDescriptors::RevokedOfferedHTLC || *$input_type == InputDescriptors::RevokedReceivedHTLC {
2981                                         $sighash_parts.access_witness($idx).push(pubkey.clone().serialize().to_vec());
2982                                 } else if *$input_type == InputDescriptors::ReceivedHTLC {
2983                                         $sighash_parts.access_witness($idx).push(vec![0]);
2984                                 } else {
2985                                         $sighash_parts.access_witness($idx).push(PaymentPreimage([1; 32]).0.to_vec());
2986                                 }
2987                                 $sighash_parts.access_witness($idx).push(redeem_script.into_bytes());
2988                                 println!("witness[0] {}", $sighash_parts.access_witness($idx)[0].len());
2989                                 println!("witness[1] {}", $sighash_parts.access_witness($idx)[1].len());
2990                                 println!("witness[2] {}", $sighash_parts.access_witness($idx)[2].len());
2991                         }
2992                 }
2993
2994                 let script_pubkey = Builder::new().push_opcode(opcodes::all::OP_RETURN).into_script();
2995                 let txid = Txid::from_hex("56944c5d3f98413ef45cf54545538103cc9f298e0575820ad3591376e2e0f65d").unwrap();
2996
2997                 // Justice tx with 1 to_holder, 2 revoked offered HTLCs, 1 revoked received HTLCs
2998                 let mut claim_tx = Transaction { version: 0, lock_time: 0, input: Vec::new(), output: Vec::new() };
2999                 for i in 0..4 {
3000                         claim_tx.input.push(TxIn {
3001                                 previous_output: BitcoinOutPoint {
3002                                         txid,
3003                                         vout: i,
3004                                 },
3005                                 script_sig: Script::new(),
3006                                 sequence: 0xfffffffd,
3007                                 witness: Vec::new(),
3008                         });
3009                 }
3010                 claim_tx.output.push(TxOut {
3011                         script_pubkey: script_pubkey.clone(),
3012                         value: 0,
3013                 });
3014                 let base_weight = claim_tx.get_weight();
3015                 let inputs_des = vec![InputDescriptors::RevokedOutput, InputDescriptors::RevokedOfferedHTLC, InputDescriptors::RevokedOfferedHTLC, InputDescriptors::RevokedReceivedHTLC];
3016                 {
3017                         let mut sighash_parts = bip143::SigHashCache::new(&mut claim_tx);
3018                         for (idx, inp) in inputs_des.iter().enumerate() {
3019                                 sign_input!(sighash_parts, idx, 0, inp, sum_actual_sigs);
3020                         }
3021                 }
3022                 assert_eq!(base_weight + OnchainTxHandler::<InMemorySigner>::get_witnesses_weight(&inputs_des[..]),  claim_tx.get_weight() + /* max_length_sig */ (73 * inputs_des.len() - sum_actual_sigs));
3023
3024                 // Claim tx with 1 offered HTLCs, 3 received HTLCs
3025                 claim_tx.input.clear();
3026                 sum_actual_sigs = 0;
3027                 for i in 0..4 {
3028                         claim_tx.input.push(TxIn {
3029                                 previous_output: BitcoinOutPoint {
3030                                         txid,
3031                                         vout: i,
3032                                 },
3033                                 script_sig: Script::new(),
3034                                 sequence: 0xfffffffd,
3035                                 witness: Vec::new(),
3036                         });
3037                 }
3038                 let base_weight = claim_tx.get_weight();
3039                 let inputs_des = vec![InputDescriptors::OfferedHTLC, InputDescriptors::ReceivedHTLC, InputDescriptors::ReceivedHTLC, InputDescriptors::ReceivedHTLC];
3040                 {
3041                         let mut sighash_parts = bip143::SigHashCache::new(&mut claim_tx);
3042                         for (idx, inp) in inputs_des.iter().enumerate() {
3043                                 sign_input!(sighash_parts, idx, 0, inp, sum_actual_sigs);
3044                         }
3045                 }
3046                 assert_eq!(base_weight + OnchainTxHandler::<InMemorySigner>::get_witnesses_weight(&inputs_des[..]),  claim_tx.get_weight() + /* max_length_sig */ (73 * inputs_des.len() - sum_actual_sigs));
3047
3048                 // Justice tx with 1 revoked HTLC-Success tx output
3049                 claim_tx.input.clear();
3050                 sum_actual_sigs = 0;
3051                 claim_tx.input.push(TxIn {
3052                         previous_output: BitcoinOutPoint {
3053                                 txid,
3054                                 vout: 0,
3055                         },
3056                         script_sig: Script::new(),
3057                         sequence: 0xfffffffd,
3058                         witness: Vec::new(),
3059                 });
3060                 let base_weight = claim_tx.get_weight();
3061                 let inputs_des = vec![InputDescriptors::RevokedOutput];
3062                 {
3063                         let mut sighash_parts = bip143::SigHashCache::new(&mut claim_tx);
3064                         for (idx, inp) in inputs_des.iter().enumerate() {
3065                                 sign_input!(sighash_parts, idx, 0, inp, sum_actual_sigs);
3066                         }
3067                 }
3068                 assert_eq!(base_weight + OnchainTxHandler::<InMemorySigner>::get_witnesses_weight(&inputs_des[..]), claim_tx.get_weight() + /* max_length_isg */ (73 * inputs_des.len() - sum_actual_sigs));
3069         }
3070
3071         // Further testing is done in the ChannelManager integration tests.
3072 }