(XXX: Add tests) Handle 1-conf funding_locked in channel no matter the event order

See comment in the diff for more details

Author: TheBlueMatt

lightning/src/ln/channel.rs

@@ -3501,11 +3501,63 @@ impl<Signer: Sign> Channel<Signer> {
 		self.network_sync == UpdateStatus::DisabledMarked
 	}
 
+	fn check_get_funding_locked(&mut self, height: u32) -> Option<msgs::FundingLocked> {
+		if self.funding_tx_confirmation_height <= 0 {
+			return None;
+		}
+
+		let funding_tx_confirmations = height as i64 - self.funding_tx_confirmation_height as i64 + 1;
+		if funding_tx_confirmations <= 0 {
+			self.funding_tx_confirmation_height = 0;
+		}
+
+		if funding_tx_confirmations < self.minimum_depth as i64 {
+			return None;
+		}
+
+		let non_shutdown_state = self.channel_state & (!MULTI_STATE_FLAGS);
+		let need_commitment_update = if non_shutdown_state == ChannelState::FundingSent as u32 {
+			self.channel_state |= ChannelState::OurFundingLocked as u32;
+			true
+		} else if non_shutdown_state == (ChannelState::FundingSent as u32 | ChannelState::TheirFundingLocked as u32) {
+			self.channel_state = ChannelState::ChannelFunded as u32 | (self.channel_state & MULTI_STATE_FLAGS);
+			self.update_time_counter += 1;
+			true
+		} else if non_shutdown_state == (ChannelState::FundingSent as u32 | ChannelState::OurFundingLocked as u32) {
+			// We got a reorg but not enough to trigger a force close, just update
+			// funding_tx_confirmed_in and return.
+			false
+		} else if self.channel_state < ChannelState::ChannelFunded as u32 {
+			panic!("Started confirming a channel in a state pre-FundingSent?: {}", self.channel_state);
+		} else {
+			// We got a reorg but not enough to trigger a force close, just update
+			// funding_tx_confirmed_in and return.
+			false
+		};
+
+		//TODO: Note that this must be a duplicate of the previous commitment point they sent us,
+		//as otherwise we will have a commitment transaction that they can't revoke (well, kinda,
+		//they can by sending two revoke_and_acks back-to-back, but not really). This appears to be
+		//a protocol oversight, but I assume I'm just missing something.
+		if need_commitment_update {
+			if self.channel_state & (ChannelState::MonitorUpdateFailed as u32) == 0 {
+				let next_per_commitment_point = self.holder_signer.get_per_commitment_point(self.cur_holder_commitment_transaction_number, &self.secp_ctx);
+				return Some(msgs::FundingLocked {
+					channel_id: self.channel_id,
+					next_per_commitment_point,
+				});
+			} else {
+				self.monitor_pending_funding_locked = true;
+			}
+		}
+		None
+	}
+
 	/// 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 {
+			-> Result<Option<msgs::FundingLocked>, msgs::ErrorMessage> where L::Target: Logger {
 		let non_shutdown_state = self.channel_state & (!MULTI_STATE_FLAGS);
 		for &(index_in_block, tx) in txdata.iter() {
 			if let Some(funding_txo) = self.get_funding_txo() {
@@ -3548,6 +3600,13 @@ impl<Signer: Sign> Channel<Signer> {
 							}
 						}
 					}
+					// If we allow 1-conf funding, we may need to check for funding_locked here and
+					// send it immediately instead of waiting for an update_best_block call (which
+					// may have already happened for this block).
+					// XXX: Test this case!
+					if let Some(funding_locked) = self.check_get_funding_locked(height) {
+						return Ok(Some(funding_locked));
+					}
 				}
 				for inp in tx.input.iter() {
 					if inp.previous_output == funding_txo.into_bitcoin_outpoint() {
@@ -3560,7 +3619,7 @@ impl<Signer: Sign> Channel<Signer> {
 				}
 			}
 		}
-		Ok(())
+		Ok(None)
 	}
 
 	/// When a new block is connected, we check the height of the block against outbound holding
@@ -3590,13 +3649,15 @@ impl<Signer: Sign> Channel<Signer> {
 		});
 
 		self.update_time_counter = cmp::max(self.update_time_counter, highest_header_time);
+
+		if let Some(funding_locked) = self.check_get_funding_locked(height) {
+			return Ok((Some(funding_locked), timed_out_htlcs));
+		}
+
 		if self.funding_tx_confirmation_height > 0 {
 			let funding_tx_confirmations = height as i64 - self.funding_tx_confirmation_height as i64 + 1;
-			if funding_tx_confirmations <= 0 {
-				self.funding_tx_confirmation_height = 0;
-			}
-
 			let non_shutdown_state = self.channel_state & (!MULTI_STATE_FLAGS);
+
 			if (non_shutdown_state >= ChannelState::ChannelFunded as u32 ||
 			   (non_shutdown_state & ChannelState::OurFundingLocked as u32) == ChannelState::OurFundingLocked as u32) &&
 			    funding_tx_confirmations < self.minimum_depth as i64 / 2 {
@@ -3605,44 +3666,6 @@ impl<Signer: Sign> Channel<Signer> {
 					data: format!("Funding transaction was un-confirmed. Locked at {} confs, now have {} confs.", self.minimum_depth, funding_tx_confirmations),
 				});
 			}
-
-			if funding_tx_confirmations == self.minimum_depth as i64 {
-				let need_commitment_update = if non_shutdown_state == ChannelState::FundingSent as u32 {
-					self.channel_state |= ChannelState::OurFundingLocked as u32;
-					true
-				} else if non_shutdown_state == (ChannelState::FundingSent as u32 | ChannelState::TheirFundingLocked as u32) {
-					self.channel_state = ChannelState::ChannelFunded as u32 | (self.channel_state & MULTI_STATE_FLAGS);
-					self.update_time_counter += 1;
-					true
-				} else if non_shutdown_state == (ChannelState::FundingSent as u32 | ChannelState::OurFundingLocked as u32) {
-					// We got a reorg but not enough to trigger a force close, just update
-					// funding_tx_confirmed_in and return.
-					false
-				} else if self.channel_state < ChannelState::ChannelFunded as u32 {
-					panic!("Started confirming a channel in a state pre-FundingSent?: {}", self.channel_state);
-				} else {
-					// We got a reorg but not enough to trigger a force close, just update
-					// funding_tx_confirmed_in and return.
-					false
-				};
-
-				//TODO: Note that this must be a duplicate of the previous commitment point they sent us,
-				//as otherwise we will have a commitment transaction that they can't revoke (well, kinda,
-				//they can by sending two revoke_and_acks back-to-back, but not really). This appears to be
-				//a protocol oversight, but I assume I'm just missing something.
-				if need_commitment_update {
-					if self.channel_state & (ChannelState::MonitorUpdateFailed as u32) == 0 {
-						let next_per_commitment_point = self.holder_signer.get_per_commitment_point(self.cur_holder_commitment_transaction_number, &self.secp_ctx);
-						return Ok((Some(msgs::FundingLocked {
-							channel_id: self.channel_id,
-							next_per_commitment_point,
-						}), timed_out_htlcs));
-					} else {
-						self.monitor_pending_funding_locked = true;
-						return Ok((None, timed_out_htlcs));
-					}
-				}
-			}
 		}
 
 		Ok((None, timed_out_htlcs))

lightning/src/ln/channelmanager.rs

@@ -3427,7 +3427,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 		log_trace!(self.logger, "{} transactions included in block {} at height {} provided", txdata.len(), block_hash, height);
 
 		let _persistence_guard = PersistenceNotifierGuard::new(&self.total_consistency_lock, &self.persistence_notifier);
-		self.do_chain_event(height, |channel| channel.transactions_confirmed(&block_hash, height, txdata, &self.logger).map(|_| (None, Vec::new())));
+		self.do_chain_event(height, |channel| channel.transactions_confirmed(&block_hash, height, txdata, &self.logger).map(|a| (a, Vec::new())));
 	}
 
 	/// Updates channel state with the current best blockchain tip. You should attempt to call this