Add preimages extraction in block_connected to claim funds

backward

Add caching of PreviousHopData even in case of non-terminal peer to be
able to route backward from on-chain resolution and prune them when htlc
is updated by other node

Author: Antoine Riard

src/ln/channel.rs

@@ -1508,7 +1508,7 @@ impl Channel {
 
 	/// Removes an outbound HTLC which has been commitment_signed by the remote end
 	#[inline]
-	fn mark_outbound_htlc_removed(&mut self, htlc_id: u64, check_preimage: Option<[u8; 32]>, fail_reason: Option<HTLCFailReason>) -> Result<&HTLCSource, ChannelError> {
+	fn mark_outbound_htlc_removed(&mut self, htlc_id: u64, check_preimage: Option<[u8; 32]>, fail_reason: Option<HTLCFailReason>) -> Result<(&HTLCSource, [u8;32]), ChannelError> {
 		for htlc in self.pending_outbound_htlcs.iter_mut() {
 			if htlc.htlc_id == htlc_id {
 				match check_preimage {
@@ -1528,13 +1528,13 @@ impl Channel {
 					OutboundHTLCState::AwaitingRemoteRevokeToRemove | OutboundHTLCState::AwaitingRemovedRemoteRevoke | OutboundHTLCState::RemoteRemoved =>
 						return Err(ChannelError::Close("Remote tried to fulfill HTLC that they'd already fulfilled")),
 				}
-				return Ok(&htlc.source);
+				return Ok((&htlc.source, htlc.payment_hash));
 			}
 		}
 		Err(ChannelError::Close("Remote tried to fulfill/fail an HTLC we couldn't find"))
 	}
 
-	pub fn update_fulfill_htlc(&mut self, msg: &msgs::UpdateFulfillHTLC) -> Result<&HTLCSource, ChannelError> {
+	pub fn update_fulfill_htlc(&mut self, msg: &msgs::UpdateFulfillHTLC) -> Result<(&HTLCSource, [u8;32]), ChannelError> {
 		if (self.channel_state & (ChannelState::ChannelFunded as u32)) != (ChannelState::ChannelFunded as u32) {
 			return Err(ChannelError::Close("Got fulfill HTLC message when channel was not in an operational state"));
 		}
@@ -1550,7 +1550,7 @@ impl Channel {
 		self.mark_outbound_htlc_removed(msg.htlc_id, Some(payment_hash), None)
 	}
 
-	pub fn update_fail_htlc(&mut self, msg: &msgs::UpdateFailHTLC, fail_reason: HTLCFailReason) -> Result<&HTLCSource, ChannelError> {
+	pub fn update_fail_htlc(&mut self, msg: &msgs::UpdateFailHTLC, fail_reason: HTLCFailReason) -> Result<(&HTLCSource, [u8;32]), ChannelError> {
 		if (self.channel_state & (ChannelState::ChannelFunded as u32)) != (ChannelState::ChannelFunded as u32) {
 			return Err(ChannelError::Close("Got fail HTLC message when channel was not in an operational state"));
 		}
@@ -1561,7 +1561,7 @@ impl Channel {
 		self.mark_outbound_htlc_removed(msg.htlc_id, None, Some(fail_reason))
 	}
 
-	pub fn update_fail_malformed_htlc<'a>(&mut self, msg: &msgs::UpdateFailMalformedHTLC, fail_reason: HTLCFailReason) -> Result<&HTLCSource, ChannelError> {
+	pub fn update_fail_malformed_htlc<'a>(&mut self, msg: &msgs::UpdateFailMalformedHTLC, fail_reason: HTLCFailReason) -> Result<(&HTLCSource, [u8;32]), ChannelError> {
 		if (self.channel_state & (ChannelState::ChannelFunded as u32)) != (ChannelState::ChannelFunded as u32) {
 			return Err(ChannelError::Close("Got fail malformed HTLC message when channel was not in an operational state"));
 		}
@@ -2928,7 +2928,7 @@ impl Channel {
 	/// those explicitly stated to be allowed after shutdown completes, eg some simple getters).
 	/// Also returns the list of payment_hashes for channels which we can safely fail backwards
 	/// immediately (others we will have to allow to time out).
-	pub fn force_shutdown(&mut self) -> (Vec<Transaction>, Vec<(HTLCSource, [u8; 32])>) {
+	pub fn force_shutdown(&mut self) -> (Vec<Transaction>, Vec<(HTLCSource, [u8; 32])>, Vec<[u8;32]>) {
 		assert!(self.channel_state != ChannelState::ShutdownComplete as u32);
 
 		// We go ahead and "free" any holding cell HTLCs or HTLCs we haven't yet committed to and
@@ -2943,17 +2943,19 @@ impl Channel {
 			}
 		}
 
-		for _htlc in self.pending_outbound_htlcs.drain(..) {
-			//TODO: Do something with the remaining HTLCs
-			//(we need to have the ChannelManager monitor them so we can claim the inbound HTLCs
-			//which correspond)
+		let mut unsolved_htlcs = Vec::with_capacity(self.pending_outbound_htlcs.len() + self.pending_inbound_htlcs.len());
+		for outbound_htlcs in self.pending_outbound_htlcs.iter() {
+			unsolved_htlcs.push(outbound_htlcs.payment_hash);
+		}
+		for inbound_htlcs in self.pending_inbound_htlcs.iter() {
+			unsolved_htlcs.push(inbound_htlcs.payment_hash);
 		}
 
 		self.channel_state = ChannelState::ShutdownComplete as u32;
 		self.channel_update_count += 1;
 		let mut res = Vec::new();
 		mem::swap(&mut res, &mut self.last_local_commitment_txn);
-		(res, dropped_outbound_htlcs)
+		(res, dropped_outbound_htlcs, unsolved_htlcs)
 	}
 }