Pass along ChannelManager's last_block_hash

ChannelMonitor keeps track of the last block connected. However, it is
initialized with the default block hash, which is a problem if the
ChannelMonitor is serialized before a block is connected. Instead, pass
ChannelManager's last_block_hash, which is initialized with a "birthday"
hash, when creating a new ChannelMonitor.

Author: jkczyz

lightning/src/chain/channelmonitor.rs

@@ -980,7 +980,8 @@ impl<Signer: Sign> ChannelMonitor<Signer> {
 	                  channel_parameters: &ChannelTransactionParameters,
 	                  funding_redeemscript: Script, channel_value_satoshis: u64,
 	                  commitment_transaction_number_obscure_factor: u64,
-	                  initial_holder_commitment_tx: HolderCommitmentTransaction) -> ChannelMonitor<Signer> {
+	                  initial_holder_commitment_tx: HolderCommitmentTransaction,
+	                  last_block_hash: BlockHash) -> ChannelMonitor<Signer> {
 
 		assert!(commitment_transaction_number_obscure_factor <= (1 << 48));
 		let our_channel_close_key_hash = WPubkeyHash::hash(&shutdown_pubkey.serialize());
@@ -1067,7 +1068,7 @@ impl<Signer: Sign> ChannelMonitor<Signer> {
 				lockdown_from_offchain: false,
 				holder_tx_signed: false,
 
-				last_block_hash: Default::default(),
+				last_block_hash,
 				secp_ctx,
 			}),
 		}
@@ -2789,6 +2790,7 @@ 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};
@@ -2798,6 +2800,7 @@ mod tests {
 	use bitcoin::hashes::sha256::Hash as Sha256;
 	use bitcoin::hashes::hex::FromHex;
 	use bitcoin::hash_types::Txid;
+	use bitcoin::network::constants::Network;
 	use hex;
 	use chain::channelmonitor::ChannelMonitor;
 	use chain::transaction::OutPoint;
@@ -2897,12 +2900,13 @@ 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 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());
+		                                  HolderCommitmentTransaction::dummy(), last_block_hash);
 
 		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

@@ -1516,7 +1516,7 @@ impl<Signer: Sign> Channel<Signer> {
 		&self.get_counterparty_pubkeys().funding_pubkey
 	}
 
-	pub fn funding_created<L: Deref>(&mut self, msg: &msgs::FundingCreated, logger: &L) -> Result<(msgs::FundingSigned, ChannelMonitor<Signer>), ChannelError> where L::Target: Logger {
+	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 {
 		if self.is_outbound() {
 			return Err(ChannelError::Close("Received funding_created for an outbound channel?".to_owned()));
 		}
@@ -1570,7 +1570,7 @@ impl<Signer: Sign> Channel<Signer> {
 		                                          &self.channel_transaction_parameters,
 		                                          funding_redeemscript.clone(), self.channel_value_satoshis,
 		                                          obscure_factor,
-		                                          holder_commitment_tx);
+		                                          holder_commitment_tx, last_block_hash);
 
 		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);
 
@@ -1587,7 +1587,7 @@ 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, logger: &L) -> Result<ChannelMonitor<Signer>, ChannelError> where L::Target: Logger {
+	pub fn funding_signed<L: Deref>(&mut self, msg: &msgs::FundingSigned, last_block_hash: BlockHash, logger: &L) -> Result<ChannelMonitor<Signer>, ChannelError> where L::Target: Logger {
 		if !self.is_outbound() {
 			return Err(ChannelError::Close("Received funding_signed for an inbound channel?".to_owned()));
 		}
@@ -1640,7 +1640,7 @@ impl<Signer: Sign> Channel<Signer> {
 		                                          &self.channel_transaction_parameters,
 		                                          funding_redeemscript.clone(), self.channel_value_satoshis,
 		                                          obscure_factor,
-		                                          holder_commitment_tx);
+		                                          holder_commitment_tx, last_block_hash);
 
 		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);
 
@@ -4910,6 +4910,8 @@ 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 keys_provider = test_utils::TestKeysInterface::new(&seed, network);
 
 		// Go through the flow of opening a channel between two nodes.
@@ -4920,7 +4922,7 @@ mod tests {
 		let mut node_a_chan = Channel::<EnforcingSigner>::new_outbound(&&feeest, &&keys_provider, node_b_node_id, 10000000, 100000, 42, &config).unwrap();
 
 		// Create Node B's channel by receiving Node A's open_channel message
-		let open_channel_msg = node_a_chan.get_open_channel(genesis_block(network).header.block_hash());
+		let open_channel_msg = node_a_chan.get_open_channel(chain_hash);
 		let node_b_node_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[7; 32]).unwrap());
 		let mut node_b_chan = Channel::<EnforcingSigner>::new_from_req(&&feeest, &&keys_provider, node_b_node_id, InitFeatures::known(), &open_channel_msg, 7, &config).unwrap();
 
@@ -4935,10 +4937,10 @@ mod tests {
 		}]};
 		let funding_outpoint = OutPoint{ txid: tx.txid(), index: 0 };
 		let funding_created_msg = node_a_chan.get_outbound_funding_created(funding_outpoint, &&logger).unwrap();
-		let (funding_signed_msg, _) = node_b_chan.funding_created(&funding_created_msg, &&logger).unwrap();
+		let (funding_signed_msg, _) = node_b_chan.funding_created(&funding_created_msg, last_block_hash, &&logger).unwrap();
 
 		// Node B --> Node A: funding signed
-		let _ = node_a_chan.funding_signed(&funding_signed_msg, &&logger);
+		let _ = node_a_chan.funding_signed(&funding_signed_msg, last_block_hash, &&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

@@ -2461,7 +2461,8 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 					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, &self.logger), channel_state, chan), chan.remove())
+					let last_block_hash = *self.last_block_hash.lock().unwrap();
+					(try_chan_entry!(self, chan.get_mut().funding_created(msg, last_block_hash, &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))
 			}
@@ -2517,7 +2518,8 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 					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 = match chan.get_mut().funding_signed(&msg, &self.logger) {
+					let last_block_hash = *self.last_block_hash.lock().unwrap();
+					let monitor = match chan.get_mut().funding_signed(&msg, last_block_hash, &self.logger) {
 						Ok(update) => update,
 						Err(e) => try_chan_entry!(self, Err(e), channel_state, chan),
 					};