Parameterize ChannelManager::new with a block hash

When ChannelMonitors are persisted, they need to store the most recent
block hash seen. However, for newly created channels the default block
hash is used. If persisted before a block is connected, the funding
output may be missed when syncing after a restart. Instead, initialize
ChannelManager with a "birthday" hash so it can be used later when
creating channels.

Author: jkczyz

background-processor/src/lib.rs

@@ -106,7 +106,7 @@ mod tests {
 	use lightning::chain::keysinterface::{Sign, InMemorySigner, KeysInterface, KeysManager};
 	use lightning::chain::transaction::OutPoint;
 	use lightning::get_event_msg;
-	use lightning::ln::channelmanager::{ChannelManager, SimpleArcChannelManager};
+	use lightning::ln::channelmanager::{ChainParameters, ChannelManager, SimpleArcChannelManager};
 	use lightning::ln::features::InitFeatures;
 	use lightning::ln::msgs::ChannelMessageHandler;
 	use lightning::util::config::UserConfig;
@@ -155,10 +155,16 @@ mod tests {
 			let persister = Arc::new(FilesystemPersister::new(format!("{}_persister_{}", persist_dir, i)));
 			let seed = [i as u8; 32];
 			let network = Network::Testnet;
-			let now = Duration::from_secs(genesis_block(network).header.time as u64);
+			let genesis_block = genesis_block(network);
+			let now = Duration::from_secs(genesis_block.header.time as u64);
 			let keys_manager = Arc::new(KeysManager::new(&seed, now.as_secs(), now.subsec_nanos()));
 			let chain_monitor = Arc::new(chainmonitor::ChainMonitor::new(Some(chain_source.clone()), tx_broadcaster.clone(), logger.clone(), fee_estimator.clone(), persister.clone()));
-			let manager = Arc::new(ChannelManager::new(Network::Testnet, fee_estimator.clone(), chain_monitor.clone(), tx_broadcaster, logger.clone(), keys_manager.clone(), UserConfig::default(), i));
+			let params = ChainParameters {
+				network,
+				latest_hash: genesis_block.block_hash(),
+				latest_height: 0,
+			};
+			let manager = Arc::new(ChannelManager::new(fee_estimator.clone(), chain_monitor.clone(), tx_broadcaster, logger.clone(), keys_manager.clone(), UserConfig::default(), params));
 			let node = Node { node: manager, persister, logger };
 			nodes.push(node);
 		}

lightning/src/ln/channelmanager.rs

@@ -451,6 +451,24 @@ pub struct ChannelManager<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref,
 	logger: L,
 }
 
+/// Chain-related parameters used to construct a new `ChannelManager`.
+///
+/// Typically, the block-specific parameters are derived from the best block hash for the network,
+/// as a newly constructed `ChannelManager` will not have created any channels yet. These parameters
+/// are not needed when deserializing a previously constructed `ChannelManager`.
+pub struct ChainParameters {
+	/// The network for determining the `chain_hash` in Lightning messages.
+	pub network: Network,
+
+	/// The hash of the latest block successfully connected.
+	pub latest_hash: BlockHash,
+
+	/// The height of the latest block successfully connected.
+	///
+	/// Used to track on-chain channel funding outputs and send payments with reliable timelocks.
+	pub latest_height: usize,
+}
+
 /// Whenever we release the `ChannelManager`'s `total_consistency_lock`, from read mode, it is
 /// desirable to notify any listeners on `wait_timeout`/`wait` that new updates are available for
 /// persistence. Therefore, this struct is responsible for locking the total consistency lock and,
@@ -760,24 +778,21 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 	///
 	/// panics if channel_value_satoshis is >= `MAX_FUNDING_SATOSHIS`!
 	///
-	/// Users must provide the current blockchain height from which to track onchain channel
-	/// funding outpoints and send payments with reliable timelocks.
-	///
 	/// Users need to notify the new ChannelManager when a new block is connected or
 	/// disconnected using its `block_connected` and `block_disconnected` methods.
-	pub fn new(network: Network, fee_est: F, chain_monitor: M, tx_broadcaster: T, logger: L, keys_manager: K, config: UserConfig, current_blockchain_height: usize) -> Self {
+	pub fn new(fee_est: F, chain_monitor: M, tx_broadcaster: T, logger: L, keys_manager: K, config: UserConfig, params: ChainParameters) -> Self {
 		let mut secp_ctx = Secp256k1::new();
 		secp_ctx.seeded_randomize(&keys_manager.get_secure_random_bytes());
 
 		ChannelManager {
 			default_configuration: config.clone(),
-			genesis_hash: genesis_block(network).header.block_hash(),
+			genesis_hash: genesis_block(params.network).header.block_hash(),
 			fee_estimator: fee_est,
 			chain_monitor,
 			tx_broadcaster,
 
-			latest_block_height: AtomicUsize::new(current_blockchain_height),
-			last_block_hash: Mutex::new(Default::default()),
+			latest_block_height: AtomicUsize::new(params.latest_height),
+			last_block_hash: Mutex::new(params.latest_hash),
 			secp_ctx,
 
 			channel_state: Mutex::new(ChannelHolder{

lightning/src/ln/functional_test_utils.rs

@@ -13,7 +13,7 @@
 use chain::Watch;
 use chain::channelmonitor::ChannelMonitor;
 use chain::transaction::OutPoint;
-use ln::channelmanager::{ChannelManager, ChannelManagerReadArgs, RAACommitmentOrder, PaymentPreimage, PaymentHash, PaymentSecret, PaymentSendFailure};
+use ln::channelmanager::{ChainParameters, ChannelManager, ChannelManagerReadArgs, RAACommitmentOrder, PaymentPreimage, PaymentHash, PaymentSecret, PaymentSendFailure};
 use routing::router::{Route, get_route};
 use routing::network_graph::{NetGraphMsgHandler, NetworkGraph};
 use ln::features::InitFeatures;
@@ -28,6 +28,7 @@ use util::config::UserConfig;
 use util::ser::{ReadableArgs, Writeable, Readable};
 
 use bitcoin::blockdata::block::{Block, BlockHeader};
+use bitcoin::blockdata::constants::genesis_block;
 use bitcoin::blockdata::transaction::{Transaction, TxOut};
 use bitcoin::network::constants::Network;
 
@@ -1161,7 +1162,13 @@ pub fn create_node_chanmgrs<'a, 'b>(node_count: usize, cfgs: &'a Vec<NodeCfg<'b>
 		default_config.channel_options.announced_channel = true;
 		default_config.peer_channel_config_limits.force_announced_channel_preference = false;
 		default_config.own_channel_config.our_htlc_minimum_msat = 1000; // sanitization being done by the sender, to exerce receiver logic we need to lift of limit
-		let node = ChannelManager::new(Network::Testnet, cfgs[i].fee_estimator, &cfgs[i].chain_monitor, cfgs[i].tx_broadcaster, cfgs[i].logger, cfgs[i].keys_manager, if node_config[i].is_some() { node_config[i].clone().unwrap() } else { default_config }, 0);
+		let network = Network::Testnet;
+		let params = ChainParameters {
+			network,
+			latest_hash: genesis_block(network).header.block_hash(),
+			latest_height: 0,
+		};
+		let node = ChannelManager::new(cfgs[i].fee_estimator, &cfgs[i].chain_monitor, cfgs[i].tx_broadcaster, cfgs[i].logger, cfgs[i].keys_manager, if node_config[i].is_some() { node_config[i].clone().unwrap() } else { default_config }, params);
 		chanmgrs.push(node);
 	}