Track block height in ChannelMonitor

Author: jkczyz

lightning/src/chain/channelmonitor.rs

@@ -37,7 +37,7 @@ use bitcoin::secp256k1;
 use ln::msgs::DecodeError;
 use ln::chan_utils;
 use ln::chan_utils::{CounterpartyCommitmentSecrets, HTLCOutputInCommitment, HTLCType, ChannelTransactionParameters, HolderCommitmentTransaction};
-use ln::channelmanager::{HTLCSource, PaymentPreimage, PaymentHash};
+use ln::channelmanager::{BestBlock, HTLCSource, PaymentPreimage, PaymentHash};
 use ln::onchaintx::{OnchainTxHandler, InputDescriptors};
 use chain;
 use chain::WatchedOutput;
@@ -735,12 +735,13 @@ pub(crate) struct ChannelMonitorImpl<Signer: Sign> {
 	// remote monitor out-of-order with regards to the block view.
 	holder_tx_signed: bool,
 
-	// We simply modify last_block_hash in Channel's block_connected so that serialization is
+	// We simply modify best_block in Channel's block_connected so that serialization is
 	// consistent but hopefully the users' copy handles block_connected in a consistent way.
 	// (we do *not*, however, update them in update_monitor to ensure any local user copies keep
-	// their last_block_hash from its state and not based on updated copies that didn't run through
+	// their best_block from its state and not based on updated copies that didn't run through
 	// the full block_connected).
-	last_block_hash: BlockHash,
+	best_block: BestBlock,
+
 	secp_ctx: Secp256k1<secp256k1::All>, //TODO: dedup this a bit...
 }
 
@@ -952,7 +953,8 @@ impl<Signer: Sign> Writeable for ChannelMonitorImpl<Signer> {
 			event.write(writer)?;
 		}
 
-		self.last_block_hash.write(writer)?;
+		self.best_block.block_hash().write(writer)?;
+		writer.write_all(&byte_utils::be32_to_array(self.best_block.height()))?;
 
 		writer.write_all(&byte_utils::be64_to_array(self.onchain_events_waiting_threshold_conf.len() as u64))?;
 		for ref entry in self.onchain_events_waiting_threshold_conf.iter() {
@@ -996,7 +998,7 @@ impl<Signer: Sign> ChannelMonitor<Signer> {
 	                  funding_redeemscript: Script, channel_value_satoshis: u64,
 	                  commitment_transaction_number_obscure_factor: u64,
 	                  initial_holder_commitment_tx: HolderCommitmentTransaction,
-	                  last_block_hash: BlockHash) -> ChannelMonitor<Signer> {
+	                  best_block: BestBlock) -> ChannelMonitor<Signer> {
 
 		assert!(commitment_transaction_number_obscure_factor <= (1 << 48));
 		let our_channel_close_key_hash = WPubkeyHash::hash(&shutdown_pubkey.serialize());
@@ -1083,7 +1085,8 @@ impl<Signer: Sign> ChannelMonitor<Signer> {
 				lockdown_from_offchain: false,
 				holder_tx_signed: false,
 
-				last_block_hash,
+				best_block,
+
 				secp_ctx,
 			}),
 		}
@@ -2128,7 +2131,7 @@ impl<Signer: Sign> ChannelMonitorImpl<Signer> {
 		}
 
 		self.onchain_tx_handler.update_claims_view(&txn_matched, claimable_outpoints, Some(height), &&*broadcaster, &&*fee_estimator, &&*logger);
-		self.last_block_hash = block_hash;
+		self.best_block = BestBlock::new(block_hash, height);
 
 		// Determine new outputs to watch by comparing against previously known outputs to watch,
 		// updating the latter in the process.
@@ -2167,7 +2170,7 @@ impl<Signer: Sign> ChannelMonitorImpl<Signer> {
 
 		self.onchain_tx_handler.block_disconnected(height, broadcaster, fee_estimator, logger);
 
-		self.last_block_hash = header.prev_blockhash;
+		self.best_block = BestBlock::new(header.prev_blockhash, height - 1);
 	}
 
 	/// Filters a block's `txdata` for transactions spending watched outputs or for any child
@@ -2738,7 +2741,7 @@ impl<'a, Signer: Sign, K: KeysInterface<Signer = Signer>> ReadableArgs<&'a K>
 			}
 		}
 
-		let last_block_hash: BlockHash = Readable::read(reader)?;
+		let best_block = BestBlock::new(Readable::read(reader)?, Readable::read(reader)?);
 
 		let waiting_threshold_conf_len: u64 = Readable::read(reader)?;
 		let mut onchain_events_waiting_threshold_conf = Vec::with_capacity(cmp::min(waiting_threshold_conf_len as usize, MAX_ALLOC_SIZE / 128));
@@ -2785,7 +2788,7 @@ impl<'a, Signer: Sign, K: KeysInterface<Signer = Signer>> ReadableArgs<&'a K>
 		let mut secp_ctx = Secp256k1::new();
 		secp_ctx.seeded_randomize(&keys_manager.get_secure_random_bytes());
 
-		Ok((last_block_hash.clone(), ChannelMonitor {
+		Ok((best_block.block_hash(), ChannelMonitor {
 			inner: Mutex::new(ChannelMonitorImpl {
 				latest_update_id,
 				commitment_transaction_number_obscure_factor,
@@ -2830,7 +2833,8 @@ impl<'a, Signer: Sign, K: KeysInterface<Signer = Signer>> ReadableArgs<&'a K>
 				lockdown_from_offchain,
 				holder_tx_signed,
 
-				last_block_hash,
+				best_block,
+
 				secp_ctx,
 			}),
 		}))
@@ -2839,7 +2843,6 @@ impl<'a, Signer: Sign, K: KeysInterface<Signer = Signer>> ReadableArgs<&'a K>
 
 #[cfg(test)]
 mod tests {
-	use bitcoin::blockdata::constants::genesis_block;
 	use bitcoin::blockdata::script::{Script, Builder};
 	use bitcoin::blockdata::opcodes;
 	use bitcoin::blockdata::transaction::{Transaction, TxIn, TxOut, SigHashType};
@@ -2853,7 +2856,7 @@ mod tests {
 	use hex;
 	use chain::channelmonitor::ChannelMonitor;
 	use chain::transaction::OutPoint;
-	use ln::channelmanager::{PaymentPreimage, PaymentHash};
+	use ln::channelmanager::{BestBlock, PaymentPreimage, PaymentHash};
 	use ln::onchaintx::{OnchainTxHandler, InputDescriptors};
 	use ln::chan_utils;
 	use ln::chan_utils::{HTLCOutputInCommitment, ChannelPublicKeys, ChannelTransactionParameters, HolderCommitmentTransaction, CounterpartyChannelTransactionParameters};
@@ -2949,13 +2952,13 @@ mod tests {
 		};
 		// Prune with one old state and a holder commitment tx holding a few overlaps with the
 		// old state.
-		let last_block_hash = genesis_block(Network::Testnet).block_hash();
+		let best_block = BestBlock::from_genesis(Network::Testnet);
 		let monitor = ChannelMonitor::new(Secp256k1::new(), keys,
 		                                  &PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap()), 0, &Script::new(),
 		                                  (OutPoint { txid: Txid::from_slice(&[43; 32]).unwrap(), index: 0 }, Script::new()),
 		                                  &channel_parameters,
 		                                  Script::new(), 46, 0,
-		                                  HolderCommitmentTransaction::dummy(), last_block_hash);
+		                                  HolderCommitmentTransaction::dummy(), best_block);
 
 		monitor.provide_latest_holder_commitment_tx(HolderCommitmentTransaction::dummy(), preimages_to_holder_htlcs!(preimages[0..10])).unwrap();
 		let dummy_txid = dummy_tx.txid();

lightning/src/ln/channel.rs

@@ -24,7 +24,7 @@ use bitcoin::secp256k1;
 use ln::features::{ChannelFeatures, InitFeatures};
 use ln::msgs;
 use ln::msgs::{DecodeError, OptionalField, DataLossProtect};
-use ln::channelmanager::{PendingHTLCStatus, HTLCSource, HTLCFailReason, HTLCFailureMsg, PendingHTLCInfo, RAACommitmentOrder, PaymentPreimage, PaymentHash, BREAKDOWN_TIMEOUT, MIN_CLTV_EXPIRY_DELTA, MAX_LOCAL_BREAKDOWN_TIMEOUT};
+use ln::channelmanager::{BestBlock, PendingHTLCStatus, HTLCSource, HTLCFailReason, HTLCFailureMsg, PendingHTLCInfo, RAACommitmentOrder, PaymentPreimage, PaymentHash, BREAKDOWN_TIMEOUT, MIN_CLTV_EXPIRY_DELTA, MAX_LOCAL_BREAKDOWN_TIMEOUT};
 use ln::chan_utils::{CounterpartyCommitmentSecrets, TxCreationKeys, HTLCOutputInCommitment, HTLC_SUCCESS_TX_WEIGHT, HTLC_TIMEOUT_TX_WEIGHT, make_funding_redeemscript, ChannelPublicKeys, CommitmentTransaction, HolderCommitmentTransaction, ChannelTransactionParameters, CounterpartyChannelTransactionParameters, MAX_HTLCS, get_commitment_transaction_number_obscure_factor};
 use ln::chan_utils;
 use chain::chaininterface::{FeeEstimator,ConfirmationTarget};
@@ -1531,7 +1531,7 @@ impl<Signer: Sign> Channel<Signer> {
 		&self.get_counterparty_pubkeys().funding_pubkey
 	}
 
-	pub fn funding_created<L: Deref>(&mut self, msg: &msgs::FundingCreated, last_block_hash: BlockHash, logger: &L) -> Result<(msgs::FundingSigned, ChannelMonitor<Signer>), ChannelError> where L::Target: Logger {
+	pub fn funding_created<L: Deref>(&mut self, msg: &msgs::FundingCreated, best_block: BestBlock, logger: &L) -> Result<(msgs::FundingSigned, ChannelMonitor<Signer>), ChannelError> where L::Target: Logger {
 		if self.is_outbound() {
 			return Err(ChannelError::Close("Received funding_created for an outbound channel?".to_owned()));
 		}
@@ -1585,7 +1585,7 @@ impl<Signer: Sign> Channel<Signer> {
 		                                          &self.channel_transaction_parameters,
 		                                          funding_redeemscript.clone(), self.channel_value_satoshis,
 		                                          obscure_factor,
-		                                          holder_commitment_tx, last_block_hash);
+		                                          holder_commitment_tx, best_block);
 
 		channel_monitor.provide_latest_counterparty_commitment_tx(counterparty_initial_commitment_txid, Vec::new(), self.cur_counterparty_commitment_transaction_number, self.counterparty_cur_commitment_point.unwrap(), logger);
 
@@ -1602,7 +1602,7 @@ impl<Signer: Sign> Channel<Signer> {
 
 	/// Handles a funding_signed message from the remote end.
 	/// If this call is successful, broadcast the funding transaction (and not before!)
-	pub fn funding_signed<L: Deref>(&mut self, msg: &msgs::FundingSigned, last_block_hash: BlockHash, logger: &L) -> Result<(ChannelMonitor<Signer>, Transaction), ChannelError> where L::Target: Logger {
+	pub fn funding_signed<L: Deref>(&mut self, msg: &msgs::FundingSigned, best_block: BestBlock, logger: &L) -> Result<(ChannelMonitor<Signer>, Transaction), ChannelError> where L::Target: Logger {
 		if !self.is_outbound() {
 			return Err(ChannelError::Close("Received funding_signed for an inbound channel?".to_owned()));
 		}
@@ -1655,7 +1655,7 @@ impl<Signer: Sign> Channel<Signer> {
 		                                          &self.channel_transaction_parameters,
 		                                          funding_redeemscript.clone(), self.channel_value_satoshis,
 		                                          obscure_factor,
-		                                          holder_commitment_tx, last_block_hash);
+		                                          holder_commitment_tx, best_block);
 
 		channel_monitor.provide_latest_counterparty_commitment_tx(counterparty_initial_bitcoin_tx.txid, Vec::new(), self.cur_counterparty_commitment_transaction_number, self.counterparty_cur_commitment_point.unwrap(), logger);
 
@@ -4799,7 +4799,7 @@ mod tests {
 	use bitcoin::network::constants::Network;
 	use bitcoin::hashes::hex::FromHex;
 	use hex;
-	use ln::channelmanager::{HTLCSource, PaymentPreimage, PaymentHash};
+	use ln::channelmanager::{BestBlock, HTLCSource, PaymentPreimage, PaymentHash};
 	use ln::channel::{Channel,InboundHTLCOutput,OutboundHTLCOutput,InboundHTLCState,OutboundHTLCState,HTLCOutputInCommitment,HTLCCandidate,HTLCInitiator,TxCreationKeys};
 	use ln::channel::MAX_FUNDING_SATOSHIS;
 	use ln::features::InitFeatures;
@@ -5012,8 +5012,8 @@ mod tests {
 		let secp_ctx = Secp256k1::new();
 		let seed = [42; 32];
 		let network = Network::Testnet;
-		let chain_hash = genesis_block(network).header.block_hash();
-		let last_block_hash = chain_hash;
+		let best_block = BestBlock::from_genesis(network);
+		let chain_hash = best_block.block_hash();
 		let keys_provider = test_utils::TestKeysInterface::new(&seed, network);
 
 		// Go through the flow of opening a channel between two nodes.
@@ -5039,10 +5039,10 @@ mod tests {
 		}]};
 		let funding_outpoint = OutPoint{ txid: tx.txid(), index: 0 };
 		let funding_created_msg = node_a_chan.get_outbound_funding_created(tx.clone(), funding_outpoint, &&logger).unwrap();
-		let (funding_signed_msg, _) = node_b_chan.funding_created(&funding_created_msg, last_block_hash, &&logger).unwrap();
+		let (funding_signed_msg, _) = node_b_chan.funding_created(&funding_created_msg, best_block, &&logger).unwrap();
 
 		// Node B --> Node A: funding signed
-		let _ = node_a_chan.funding_signed(&funding_signed_msg, last_block_hash, &&logger);
+		let _ = node_a_chan.funding_signed(&funding_signed_msg, best_block, &&logger);
 
 		// Now disconnect the two nodes and check that the commitment point in
 		// Node B's channel_reestablish message is sane.

lightning/src/ln/channelmanager.rs

@@ -478,6 +478,7 @@ pub struct ChainParameters {
 }
 
 /// The best known block as identified by its hash and height.
+#[derive(Clone, Copy)]
 pub struct BestBlock {
 	block_hash: BlockHash,
 	height: u32,
@@ -2543,15 +2544,15 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 
 	fn internal_funding_created(&self, counterparty_node_id: &PublicKey, msg: &msgs::FundingCreated) -> Result<(), MsgHandleErrInternal> {
 		let ((funding_msg, monitor), mut chan) = {
-			let last_block_hash = self.best_block.read().unwrap().block_hash();
+			let best_block = *self.best_block.read().unwrap();
 			let mut channel_lock = self.channel_state.lock().unwrap();
 			let channel_state = &mut *channel_lock;
 			match channel_state.by_id.entry(msg.temporary_channel_id.clone()) {
 				hash_map::Entry::Occupied(mut chan) => {
 					if chan.get().get_counterparty_node_id() != *counterparty_node_id {
 						return Err(MsgHandleErrInternal::send_err_msg_no_close("Got a message for a channel from the wrong node!".to_owned(), msg.temporary_channel_id));
 					}
-					(try_chan_entry!(self, chan.get_mut().funding_created(msg, last_block_hash, &self.logger), channel_state, chan), chan.remove())
+					(try_chan_entry!(self, chan.get_mut().funding_created(msg, best_block, &self.logger), channel_state, chan), chan.remove())
 				},
 				hash_map::Entry::Vacant(_) => return Err(MsgHandleErrInternal::send_err_msg_no_close("Failed to find corresponding channel".to_owned(), msg.temporary_channel_id))
 			}
@@ -2600,15 +2601,15 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 
 	fn internal_funding_signed(&self, counterparty_node_id: &PublicKey, msg: &msgs::FundingSigned) -> Result<(), MsgHandleErrInternal> {
 		let funding_tx = {
-			let last_block_hash = self.best_block.read().unwrap().block_hash();
+			let best_block = *self.best_block.read().unwrap();
 			let mut channel_lock = self.channel_state.lock().unwrap();
 			let channel_state = &mut *channel_lock;
 			match channel_state.by_id.entry(msg.channel_id) {
 				hash_map::Entry::Occupied(mut chan) => {
 					if chan.get().get_counterparty_node_id() != *counterparty_node_id {
 						return Err(MsgHandleErrInternal::send_err_msg_no_close("Got a message for a channel from the wrong node!".to_owned(), msg.channel_id));
 					}
-					let (monitor, funding_tx) = match chan.get_mut().funding_signed(&msg, last_block_hash, &self.logger) {
+					let (monitor, funding_tx) = match chan.get_mut().funding_signed(&msg, best_block, &self.logger) {
 						Ok(update) => update,
 						Err(e) => try_chan_entry!(self, Err(e), channel_state, chan),
 					};