_ Git - rust-lightning/blob - lightning-block-sync/src/init.rs

   1 use crate::{BlockSource, BlockSourceResult, Cache, ChainNotifier};
   2 use crate::poll::{ChainPoller, Validate, ValidatedBlockHeader};
   3
   4 use bitcoin::blockdata::block::{Block, BlockHeader};
   5 use bitcoin::hash_types::BlockHash;
   6 use bitcoin::network::constants::Network;
   7
   8 use lightning::chain::ChainListener;
   9
  10 /// Performs a one-time sync of chain listeners using a single *trusted* block source, bringing each
  11 /// listener's view of the chain from its paired block hash to `block_source`'s best chain tip.
  12 ///
  13 /// Upon success, the returned header can be used to initialize [`SpvClient`]. In the case of
  14 /// failure, each listener may be left at a different block hash than the one it was originally
  15 /// paired with.
  16 ///
  17 /// Useful during startup to bring the [`ChannelManager`] and each [`ChannelMonitor`] in sync before
  18 /// switching to [`SpvClient`]. For example:
  19 ///
  20 /// ```
  21 /// use bitcoin::hash_types::BlockHash;
  22 /// use bitcoin::network::constants::Network;
  23 ///
  24 /// use lightning::chain;
  25 /// use lightning::chain::ChainListener;
  26 /// use lightning::chain::Watch;
  27 /// use lightning::chain::chainmonitor::ChainMonitor;
  28 /// use lightning::chain::channelmonitor;
  29 /// use lightning::chain::channelmonitor::ChannelMonitor;
  30 /// use lightning::chain::chaininterface::BroadcasterInterface;
  31 /// use lightning::chain::chaininterface::FeeEstimator;
  32 /// use lightning::chain::keysinterface;
  33 /// use lightning::chain::keysinterface::KeysInterface;
  34 /// use lightning::ln::channelmanager::ChannelManager;
  35 /// use lightning::ln::channelmanager::ChannelManagerReadArgs;
  36 /// use lightning::util::config::UserConfig;
  37 /// use lightning::util::logger::Logger;
  38 /// use lightning::util::ser::ReadableArgs;
  39 ///
  40 /// use lightning_block_sync::*;
  41 ///
  42 /// use std::cell::RefCell;
  43 /// use std::io::Cursor;
  44 ///
  45 /// async fn init_sync<
  46 ///     B: BlockSource,
  47 ///     K: KeysInterface<Signer = S>,
  48 ///     S: keysinterface::Sign,
  49 ///     T: BroadcasterInterface,
  50 ///     F: FeeEstimator,
  51 ///     L: Logger,
  52 ///     C: chain::Filter,
  53 ///     P: channelmonitor::Persist<S>,
  54 /// >(
  55 ///     block_source: &mut B,
  56 ///     chain_monitor: &ChainMonitor<S, &C, &T, &F, &L, &P>,
  57 ///     config: UserConfig,
  58 ///     keys_manager: &K,
  59 ///     tx_broadcaster: &T,
  60 ///     fee_estimator: &F,
  61 ///     logger: &L,
  62 ///     persister: &P,
  63 /// ) {
  64 ///     let serialized_monitor = "...";
  65 ///     let (monitor_block_hash, mut monitor) = <(BlockHash, ChannelMonitor<S>)>::read(
  66 ///             &mut Cursor::new(&serialized_monitor), keys_manager).unwrap();
  67 ///
  68 ///     let serialized_manager = "...";
  69 ///     let (manager_block_hash, mut manager) = {
  70 ///             let read_args = ChannelManagerReadArgs::new(
  71 ///                     keys_manager,
  72 ///                     fee_estimator,
  73 ///                     chain_monitor,
  74 ///                     tx_broadcaster,
  75 ///                     logger,
  76 ///                     config,
  77 ///                     vec![&mut monitor],
  78 ///             );
  79 ///             <(BlockHash, ChannelManager<S, &ChainMonitor<S, &C, &T, &F, &L, &P>, &T, &K, &F, &L>)>::read(
  80 ///                     &mut Cursor::new(&serialized_manager), read_args).unwrap()
  81 ///     };
  82 ///
  83 ///     let mut cache = UnboundedCache::new();
  84 ///     let mut monitor_listener = (RefCell::new(monitor), &*tx_broadcaster, &*fee_estimator, &*logger);
  85 ///     let listeners = vec![
  86 ///             (monitor_block_hash, &mut monitor_listener as &mut dyn ChainListener),
  87 ///             (manager_block_hash, &mut manager as &mut dyn ChainListener),
  88 ///     ];
  89 ///     let chain_tip =
  90 ///             init::sync_listeners(block_source, Network::Bitcoin, &mut cache, listeners).await.unwrap();
  91 ///
  92 ///     let monitor = monitor_listener.0.into_inner();
  93 ///     chain_monitor.watch_channel(monitor.get_funding_txo().0, monitor);
  94 ///
  95 ///     let chain_poller = poll::ChainPoller::new(block_source, Network::Bitcoin);
  96 ///     let mut chain_listener = (chain_monitor, &manager);
  97 ///     let spv_client = SpvClient::new(chain_tip, chain_poller, &mut cache, &chain_listener);
  98 /// }
  99 /// ```
 100 ///
 101 /// [`SpvClient`]: ../struct.SpvClient.html
 102 /// [`ChannelManager`]: ../../lightning/ln/channelmanager/struct.ChannelManager.html
 103 /// [`ChannelMonitor`]: ../../lightning/chain/channelmonitor/struct.ChannelMonitor.html
 104 pub async fn sync_listeners<B: BlockSource, C: Cache>(
 105         block_source: &mut B,
 106         network: Network,
 107         header_cache: &mut C,
 108         mut chain_listeners: Vec<(BlockHash, &mut dyn ChainListener)>,
 109 ) -> BlockSourceResult<ValidatedBlockHeader> {
 110         let (best_block_hash, best_block_height) = block_source.get_best_block().await?;
 111         let new_header = block_source
 112                 .get_header(&best_block_hash, best_block_height).await?
 113                 .validate(best_block_hash)?;
 114
 115         // Fetch the header for the block hash paired with each listener.
 116         let mut chain_listeners_with_old_headers = Vec::new();
 117         for (old_block, chain_listener) in chain_listeners.drain(..) {
 118                 let old_header = match header_cache.look_up(&old_block) {
 119                         Some(header) => *header,
 120                         None => block_source
 121                                 .get_header(&old_block, None).await?
 122                                 .validate(old_block)?
 123                 };
 124                 chain_listeners_with_old_headers.push((old_header, chain_listener))
 125         }
 126
 127         // Find differences and disconnect blocks for each listener individually.
 128         let mut chain_poller = ChainPoller::new(block_source, network);
 129         let mut chain_listeners_at_height = Vec::new();
 130         let mut most_common_ancestor = None;
 131         let mut most_connected_blocks = Vec::new();
 132         for (old_header, chain_listener) in chain_listeners_with_old_headers.drain(..) {
 133                 // Disconnect any stale blocks, but keep them in the cache for the next iteration.
 134                 let header_cache = &mut ReadOnlyCache(header_cache);
 135                 let (common_ancestor, connected_blocks) = {
 136                         let chain_listener = &DynamicChainListener(chain_listener);
 137                         let mut chain_notifier = ChainNotifier { header_cache, chain_listener };
 138                         let difference =
 139                                 chain_notifier.find_difference(new_header, &old_header, &mut chain_poller).await?;
 140                         chain_notifier.disconnect_blocks(difference.disconnected_blocks);
 141                         (difference.common_ancestor, difference.connected_blocks)
 142                 };
 143
 144                 // Keep track of the most common ancestor and all blocks connected across all listeners.
 145                 chain_listeners_at_height.push((common_ancestor.height, chain_listener));
 146                 if connected_blocks.len() > most_connected_blocks.len() {
 147                         most_common_ancestor = Some(common_ancestor);
 148                         most_connected_blocks = connected_blocks;
 149                 }
 150         }
 151
 152         // Connect new blocks for all listeners at once to avoid re-fetching blocks.
 153         if let Some(common_ancestor) = most_common_ancestor {
 154                 let chain_listener = &ChainListenerSet(chain_listeners_at_height);
 155                 let mut chain_notifier = ChainNotifier { header_cache, chain_listener };
 156                 chain_notifier.connect_blocks(common_ancestor, most_connected_blocks, &mut chain_poller)
 157                         .await.or_else(|(e, _)| Err(e))?;
 158         }
 159
 160         Ok(new_header)
 161 }
 162
 163 /// A wrapper to make a cache read-only.
 164 ///
 165 /// Used to prevent losing headers that may be needed to disconnect blocks common to more than one
 166 /// listener.
 167 struct ReadOnlyCache<'a, C: Cache>(&'a mut C);
 168
 169 impl<'a, C: Cache> Cache for ReadOnlyCache<'a, C> {
 170         fn look_up(&self, block_hash: &BlockHash) -> Option<&ValidatedBlockHeader> {
 171                 self.0.look_up(block_hash)
 172         }
 173
 174         fn block_connected(&mut self, _block_hash: BlockHash, _block_header: ValidatedBlockHeader) {
 175                 unreachable!()
 176         }
 177
 178         fn block_disconnected(&mut self, _block_hash: &BlockHash) -> Option<ValidatedBlockHeader> {
 179                 None
 180         }
 181 }
 182
 183 /// Wrapper for supporting dynamically sized chain listeners.
 184 struct DynamicChainListener<'a>(&'a mut dyn ChainListener);
 185
 186 impl<'a> ChainListener for DynamicChainListener<'a> {
 187         fn block_connected(&self, _block: &Block, _height: u32) {
 188                 unreachable!()
 189         }
 190
 191         fn block_disconnected(&self, header: &BlockHeader, height: u32) {
 192                 self.0.block_disconnected(header, height)
 193         }
 194 }
 195
 196 /// A set of dynamically sized chain listeners, each paired with a starting block height.
 197 struct ChainListenerSet<'a>(Vec<(u32, &'a mut dyn ChainListener)>);
 198
 199 impl<'a> ChainListener for ChainListenerSet<'a> {
 200         fn block_connected(&self, block: &Block, height: u32) {
 201                 for (starting_height, chain_listener) in self.0.iter() {
 202                         if height > *starting_height {
 203                                 chain_listener.block_connected(block, height);
 204                         }
 205                 }
 206         }
 207
 208         fn block_disconnected(&self, _header: &BlockHeader, _height: u32) {
 209                 unreachable!()
 210         }
 211 }
 212
 213 #[cfg(test)]
 214 mod tests {
 215         use crate::test_utils::{Blockchain, MockChainListener};
 216         use super::*;
 217
 218         use bitcoin::network::constants::Network;
 219
 220         #[tokio::test]
 221         async fn sync_from_same_chain() {
 222                 let mut chain = Blockchain::default().with_height(4);
 223
 224                 let mut listener_1 = MockChainListener::new()
 225                         .expect_block_connected(*chain.at_height(2))
 226                         .expect_block_connected(*chain.at_height(3))
 227                         .expect_block_connected(*chain.at_height(4));
 228                 let mut listener_2 = MockChainListener::new()
 229                         .expect_block_connected(*chain.at_height(3))
 230                         .expect_block_connected(*chain.at_height(4));
 231                 let mut listener_3 = MockChainListener::new()
 232                         .expect_block_connected(*chain.at_height(4));
 233
 234                 let listeners = vec![
 235                         (chain.at_height(1).block_hash, &mut listener_1 as &mut dyn ChainListener),
 236                         (chain.at_height(2).block_hash, &mut listener_2 as &mut dyn ChainListener),
 237                         (chain.at_height(3).block_hash, &mut listener_3 as &mut dyn ChainListener),
 238                 ];
 239                 let mut cache = chain.header_cache(0..=4);
 240                 match sync_listeners(&mut chain, Network::Bitcoin, &mut cache, listeners).await {
 241                         Ok(header) => assert_eq!(header, chain.tip()),
 242                         Err(e) => panic!("Unexpected error: {:?}", e),
 243                 }
 244         }
 245
 246         #[tokio::test]
 247         async fn sync_from_different_chains() {
 248                 let mut main_chain = Blockchain::default().with_height(4);
 249                 let fork_chain_1 = main_chain.fork_at_height(1);
 250                 let fork_chain_2 = main_chain.fork_at_height(2);
 251                 let fork_chain_3 = main_chain.fork_at_height(3);
 252
 253                 let mut listener_1 = MockChainListener::new()
 254                         .expect_block_disconnected(*fork_chain_1.at_height(4))
 255                         .expect_block_disconnected(*fork_chain_1.at_height(3))
 256                         .expect_block_disconnected(*fork_chain_1.at_height(2))
 257                         .expect_block_connected(*main_chain.at_height(2))
 258                         .expect_block_connected(*main_chain.at_height(3))
 259                         .expect_block_connected(*main_chain.at_height(4));
 260                 let mut listener_2 = MockChainListener::new()
 261                         .expect_block_disconnected(*fork_chain_2.at_height(4))
 262                         .expect_block_disconnected(*fork_chain_2.at_height(3))
 263                         .expect_block_connected(*main_chain.at_height(3))
 264                         .expect_block_connected(*main_chain.at_height(4));
 265                 let mut listener_3 = MockChainListener::new()
 266                         .expect_block_disconnected(*fork_chain_3.at_height(4))
 267                         .expect_block_connected(*main_chain.at_height(4));
 268
 269                 let listeners = vec![
 270                         (fork_chain_1.tip().block_hash, &mut listener_1 as &mut dyn ChainListener),
 271                         (fork_chain_2.tip().block_hash, &mut listener_2 as &mut dyn ChainListener),
 272                         (fork_chain_3.tip().block_hash, &mut listener_3 as &mut dyn ChainListener),
 273                 ];
 274                 let mut cache = fork_chain_1.header_cache(2..=4);
 275                 cache.extend(fork_chain_2.header_cache(3..=4));
 276                 cache.extend(fork_chain_3.header_cache(4..=4));
 277                 match sync_listeners(&mut main_chain, Network::Bitcoin, &mut cache, listeners).await {
 278                         Ok(header) => assert_eq!(header, main_chain.tip()),
 279                         Err(e) => panic!("Unexpected error: {:?}", e),
 280                 }
 281         }
 282
 283         #[tokio::test]
 284         async fn sync_from_overlapping_chains() {
 285                 let mut main_chain = Blockchain::default().with_height(4);
 286                 let fork_chain_1 = main_chain.fork_at_height(1);
 287                 let fork_chain_2 = fork_chain_1.fork_at_height(2);
 288                 let fork_chain_3 = fork_chain_2.fork_at_height(3);
 289
 290                 let mut listener_1 = MockChainListener::new()
 291                         .expect_block_disconnected(*fork_chain_1.at_height(4))
 292                         .expect_block_disconnected(*fork_chain_1.at_height(3))
 293                         .expect_block_disconnected(*fork_chain_1.at_height(2))
 294                         .expect_block_connected(*main_chain.at_height(2))
 295                         .expect_block_connected(*main_chain.at_height(3))
 296                         .expect_block_connected(*main_chain.at_height(4));
 297                 let mut listener_2 = MockChainListener::new()
 298                         .expect_block_disconnected(*fork_chain_2.at_height(4))
 299                         .expect_block_disconnected(*fork_chain_2.at_height(3))
 300                         .expect_block_disconnected(*fork_chain_2.at_height(2))
 301                         .expect_block_connected(*main_chain.at_height(2))
 302                         .expect_block_connected(*main_chain.at_height(3))
 303                         .expect_block_connected(*main_chain.at_height(4));
 304                 let mut listener_3 = MockChainListener::new()
 305                         .expect_block_disconnected(*fork_chain_3.at_height(4))
 306                         .expect_block_disconnected(*fork_chain_3.at_height(3))
 307                         .expect_block_disconnected(*fork_chain_3.at_height(2))
 308                         .expect_block_connected(*main_chain.at_height(2))
 309                         .expect_block_connected(*main_chain.at_height(3))
 310                         .expect_block_connected(*main_chain.at_height(4));
 311
 312                 let listeners = vec![
 313                         (fork_chain_1.tip().block_hash, &mut listener_1 as &mut dyn ChainListener),
 314                         (fork_chain_2.tip().block_hash, &mut listener_2 as &mut dyn ChainListener),
 315                         (fork_chain_3.tip().block_hash, &mut listener_3 as &mut dyn ChainListener),
 316                 ];
 317                 let mut cache = fork_chain_1.header_cache(2..=4);
 318                 cache.extend(fork_chain_2.header_cache(3..=4));
 319                 cache.extend(fork_chain_3.header_cache(4..=4));
 320                 match sync_listeners(&mut main_chain, Network::Bitcoin, &mut cache, listeners).await {
 321                         Ok(header) => assert_eq!(header, main_chain.tip()),
 322                         Err(e) => panic!("Unexpected error: {:?}", e),
 323                 }
 324         }
 325
 326         #[tokio::test]
 327         async fn cache_connected_and_keep_disconnected_blocks() {
 328                 let mut main_chain = Blockchain::default().with_height(2);
 329                 let fork_chain = main_chain.fork_at_height(1);
 330                 let new_tip = main_chain.tip();
 331                 let old_tip = fork_chain.tip();
 332
 333                 let mut listener = MockChainListener::new()
 334                         .expect_block_disconnected(*old_tip)
 335                         .expect_block_connected(*new_tip);
 336
 337                 let listeners = vec![(old_tip.block_hash, &mut listener as &mut dyn ChainListener)];
 338                 let mut cache = fork_chain.header_cache(2..=2);
 339                 match sync_listeners(&mut main_chain, Network::Bitcoin, &mut cache, listeners).await {
 340                         Ok(_) => {
 341                                 assert!(cache.contains_key(&new_tip.block_hash));
 342                                 assert!(cache.contains_key(&old_tip.block_hash));
 343                         },
 344                         Err(e) => panic!("Unexpected error: {:?}", e),
 345                 }
 346         }
 347 }