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