(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 +3501,59 @@ 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 {
+			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 {
+				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 +3596,13 @@ 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 +3615,7 @@ impl<Signer: Sign> Channel<Signer> {
 				}
 			}
 		}
-		Ok(())
+		Ok(None)
 	}
 
 	/// When a new block is connected, we check the height of the block against outbound holding
@@ -3590,6 +3645,7 @@ impl<Signer: Sign> Channel<Signer> {
 		});
 
 		self.update_time_counter = cmp::max(self.update_time_counter, highest_header_time);
+
 		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 {
@@ -3606,42 +3662,8 @@ impl<Signer: Sign> Channel<Signer> {
 				});
 			}
 
-			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));
-					}
-				}
+			if let Some(funding_locked) = self.check_get_funding_locked(height) {
+				return Ok((Some(funding_locked), timed_out_htlcs));
 			}
 		}