Move ChannelManager to Channel's new block data API

This also moves the scanning of the block for commitment
transactions into channel, unifying the error path.

Author: TheBlueMatt

lightning/src/ln/channel.rs

@@ -3477,7 +3477,11 @@ impl<Signer: Sign> Channel<Signer> {
 		self.network_sync == UpdateStatus::DisabledMarked
 	}
 
-	pub fn transactions_confirmed(&mut self, block_hash: &BlockHash, height: u32, txdata: &TransactionData) -> Result<(), msgs::ErrorMessage> {
+	/// When a transaction is confirmed, we check whether it is or spends the funding transaction
+	/// In the first case, we store the confirmation height and calculating the short channel id.
+	/// In the second, we simply return an Err indicating we need to be force-closed now.
+	pub fn transactions_confirmed<L: Deref>(&mut self, block_hash: &BlockHash, height: u32, txdata: &TransactionData, logger: &L)
+			-> Result<(), msgs::ErrorMessage> where L::Target: Logger {
 		let non_shutdown_state = self.channel_state & (!MULTI_STATE_FLAGS);
 		if non_shutdown_state & !(ChannelState::TheirFundingLocked as u32) == ChannelState::FundingSent as u32 {
 			for &(index_in_block, tx) in txdata.iter() {
@@ -3523,6 +3527,15 @@ impl<Signer: Sign> Channel<Signer> {
 						                             ((txo_idx as u64)        << (0*8)));
 					}
 				}
+				for inp in tx.input.iter() {
+					if inp.previous_output == funding_txo.into_bitcoin_outpoint() {
+						log_trace!(logger, "Detected channel-closing tx {} spending {}:{}, closing channel {}", tx.txid(), inp.previous_output.txid, inp.previous_output.vout, log_bytes!(self.channel_id()));
+						return Err(msgs::ErrorMessage {
+							channel_id: self.channel_id(),
+							data: "Commitment transaction was confirmed on chain.".to_owned()
+						});
+					}
+				}
 			}
 		}
 		Ok(())
@@ -3612,25 +3625,6 @@ impl<Signer: Sign> Channel<Signer> {
 		Ok((None, timed_out_htlcs))
 	}
 
-	/// When we receive a new block, we (a) check whether the block contains the funding
-	/// transaction (which would start us counting blocks until we send the funding_signed), and
-	/// (b) check the height of the block against outbound holding cell HTLCs in case we need to
-	/// give up on them prematurely and time them out. Everything else (e.g. commitment
-	/// transaction broadcasts, channel closure detection, HTLC transaction broadcasting, etc) is
-	/// handled by the ChannelMonitor.
-	///
-	/// If we return Err, the channel may have been closed, at which point the standard
-	/// requirements apply - no calls may be made except those explicitly stated to be allowed
-	/// post-shutdown.
-	/// Only returns an ErrorAction of DisconnectPeer, if Err.
-	///
-	/// May return some HTLCs (and their payment_hash) which have timed out and should be failed
-	/// back.
-	pub fn block_connected(&mut self, header: &BlockHeader, txdata: &TransactionData, height: u32) -> Result<(Option<msgs::FundingLocked>, Vec<(HTLCSource, PaymentHash)>), msgs::ErrorMessage> {
-		self.transactions_confirmed(&header.block_hash(), height, txdata)?;
-		self.update_best_block(height, header.time)
-	}
-
 	/// Called by channelmanager based on chain blocks being disconnected.
 	/// Returns true if we need to close the channel now due to funding transaction
 	/// unconfirmation/reorg.

lightning/src/ln/channelmanager.rs

@@ -3262,7 +3262,6 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 
 		let _persistence_guard = PersistenceNotifierGuard::new(&self.total_consistency_lock, &self.persistence_notifier);
 
-
 		// This assertion should be enforced in tests, however we have a number of tests that
 		// were written before this requirement and do not meet it.
 		#[cfg(not(test))]
@@ -3283,7 +3282,8 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 			let short_to_id = &mut channel_state.short_to_id;
 			let pending_msg_events = &mut channel_state.pending_msg_events;
 			channel_state.by_id.retain(|_, channel| {
-				let res = channel.block_connected(header, txdata, height);
+				let res = channel.transactions_confirmed(&block_hash, height, txdata, &self.logger)
+					.and_then(|_| channel.update_best_block(height, header.time));
 				if let Ok((chan_res, mut timed_out_pending_htlcs)) = res {
 					for (source, payment_hash) in timed_out_pending_htlcs.drain(..) {
 						let chan_update = self.get_channel_update(&channel).map(|u| u.encode_with_len()).unwrap(); // Cannot add/recv HTLCs before we have a short_id so unwrap is safe
@@ -3309,32 +3309,22 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 						short_to_id.insert(channel.get_short_channel_id().unwrap(), channel.channel_id());
 					}
 				} else if let Err(e) = res {
+					if let Some(short_id) = channel.get_short_channel_id() {
+						short_to_id.remove(&short_id);
+					}
+					// It looks like our counterparty went on-chain. Close the channel.
+					failed_channels.push(channel.force_shutdown(true));
+					if let Ok(update) = self.get_channel_update(&channel) {
+						pending_msg_events.push(events::MessageSendEvent::BroadcastChannelUpdate {
+							msg: update
+						});
+					}
 					pending_msg_events.push(events::MessageSendEvent::HandleError {
 						node_id: channel.get_counterparty_node_id(),
 						action: msgs::ErrorAction::SendErrorMessage { msg: e },
 					});
 					return false;
 				}
-				if let Some(funding_txo) = channel.get_funding_txo() {
-					for &(_, tx) in txdata.iter() {
-						for inp in tx.input.iter() {
-							if inp.previous_output == funding_txo.into_bitcoin_outpoint() {
-								log_trace!(self.logger, "Detected channel-closing tx {} spending {}:{}, closing channel {}", tx.txid(), inp.previous_output.txid, inp.previous_output.vout, log_bytes!(channel.channel_id()));
-								if let Some(short_id) = channel.get_short_channel_id() {
-									short_to_id.remove(&short_id);
-								}
-								// It looks like our counterparty went on-chain. Close the channel.
-								failed_channels.push(channel.force_shutdown(true));
-								if let Ok(update) = self.get_channel_update(&channel) {
-									pending_msg_events.push(events::MessageSendEvent::BroadcastChannelUpdate {
-										msg: update
-									});
-								}
-								return false;
-							}
-						}
-					}
-				}
 				true
 			});