Remove remaining uses of HandleError in Channel Err return values

This converts block_connected failures to returning the
ErrorMessage that needs to be sent directly, since it always
results in channel closure and never results in needing to call
force_shutdown. It also converts update_add_htlc and closing_signed
handlers to ChannelError as the rest of the message handlers.

Author: TheBlueMatt

src/ln/channel.rs

@@ -13,7 +13,7 @@ use secp256k1;
 use crypto::digest::Digest;
 
 use ln::msgs;
-use ln::msgs::{DecodeError, ErrorAction, HandleError};
+use ln::msgs::DecodeError;
 use ln::channelmonitor::ChannelMonitor;
 use ln::channelmanager::{PendingHTLCStatus, HTLCSource, HTLCFailReason, HTLCFailureMsg, PendingForwardHTLCInfo, RAACommitmentOrder};
 use ln::chan_utils::{TxCreationKeys,HTLCOutputInCommitment,HTLC_SUCCESS_TX_WEIGHT,HTLC_TIMEOUT_TX_WEIGHT};
@@ -373,15 +373,6 @@ pub(super) enum ChannelError {
 	Close(&'static str),
 }
 
-macro_rules! secp_call {
-	( $res: expr, $err: expr, $chan_id: expr ) => {
-		match $res {
-			Ok(key) => key,
-			Err(_) => return Err(HandleError {err: $err, action: Some(msgs::ErrorAction::SendErrorMessage {msg: msgs::ErrorMessage {channel_id: $chan_id, data: $err.to_string()}})})
-		}
-	};
-}
-
 macro_rules! secp_check {
 	($res: expr, $err: expr) => {
 		match $res {
@@ -1528,40 +1519,40 @@ impl Channel {
 		(self.pending_outbound_htlcs.len() as u32, htlc_outbound_value_msat)
 	}
 
-	pub fn update_add_htlc(&mut self, msg: &msgs::UpdateAddHTLC, pending_forward_state: PendingHTLCStatus) -> Result<(), HandleError> {
+	pub fn update_add_htlc(&mut self, msg: &msgs::UpdateAddHTLC, pending_forward_state: PendingHTLCStatus) -> Result<(), ChannelError> {
 		if (self.channel_state & (ChannelState::ChannelFunded as u32 | ChannelState::RemoteShutdownSent as u32)) != (ChannelState::ChannelFunded as u32) {
-			return Err(HandleError{err: "Got add HTLC message when channel was not in an operational state", action: None});
+			return Err(ChannelError::Close("Got add HTLC message when channel was not in an operational state"));
 		}
 		if self.channel_state & (ChannelState::PeerDisconnected as u32) == ChannelState::PeerDisconnected as u32 {
-			return Err(HandleError{err: "Peer sent update_add_htlc when we needed a channel_reestablish", action: Some(msgs::ErrorAction::SendErrorMessage{msg: msgs::ErrorMessage{data: "Peer sent update_add_htlc when we needed a channel_reestablish".to_string(), channel_id: msg.channel_id}})});
+			return Err(ChannelError::Close("Peer sent update_add_htlc when we needed a channel_reestablish"));
 		}
 		if msg.amount_msat > self.channel_value_satoshis * 1000 {
-			return Err(HandleError{err: "Remote side tried to send more than the total value of the channel", action: None});
+			return Err(ChannelError::Close("Remote side tried to send more than the total value of the channel"));
 		}
 		if msg.amount_msat < self.our_htlc_minimum_msat {
-			return Err(HandleError{err: "Remote side tried to send less than our minimum HTLC value", action: None});
+			return Err(ChannelError::Close("Remote side tried to send less than our minimum HTLC value"));
 		}
 
 		let (inbound_htlc_count, htlc_inbound_value_msat) = self.get_inbound_pending_htlc_stats();
 		if inbound_htlc_count + 1 > OUR_MAX_HTLCS as u32 {
-			return Err(HandleError{err: "Remote tried to push more than our max accepted HTLCs", action: None});
+			return Err(ChannelError::Close("Remote tried to push more than our max accepted HTLCs"));
 		}
 		//TODO: Spec is unclear if this is per-direction or in total (I assume per direction):
 		// Check our_max_htlc_value_in_flight_msat
 		if htlc_inbound_value_msat + msg.amount_msat > Channel::get_our_max_htlc_value_in_flight_msat(self.channel_value_satoshis) {
-			return Err(HandleError{err: "Remote HTLC add would put them over their max HTLC value in flight", action: None});
+			return Err(ChannelError::Close("Remote HTLC add would put them over their max HTLC value in flight"));
 		}
 		// Check our_channel_reserve_satoshis (we're getting paid, so they have to at least meet
 		// the reserve_satoshis we told them to always have as direct payment so that they lose
 		// something if we punish them for broadcasting an old state).
 		if htlc_inbound_value_msat + msg.amount_msat + self.value_to_self_msat > (self.channel_value_satoshis - Channel::get_our_channel_reserve_satoshis(self.channel_value_satoshis)) * 1000 {
-			return Err(HandleError{err: "Remote HTLC add would put them over their reserve value", action: None});
+			return Err(ChannelError::Close("Remote HTLC add would put them over their reserve value"));
 		}
 		if self.next_remote_htlc_id != msg.htlc_id {
-			return Err(HandleError{err: "Remote skipped HTLC ID", action: None});
+			return Err(ChannelError::Close("Remote skipped HTLC ID"));
 		}
 		if msg.cltv_expiry >= 500000000 {
-			return Err(HandleError{err: "Remote provided CLTV expiry in seconds instead of block height", action: None});
+			return Err(ChannelError::Close("Remote provided CLTV expiry in seconds instead of block height"));
 		}
 
 		//TODO: Check msg.cltv_expiry further? Do this in channel manager?
@@ -2508,24 +2499,24 @@ impl Channel {
 		Ok((our_shutdown, self.maybe_propose_first_closing_signed(fee_estimator), dropped_outbound_htlcs))
 	}
 
-	pub fn closing_signed(&mut self, fee_estimator: &FeeEstimator, msg: &msgs::ClosingSigned) -> Result<(Option<msgs::ClosingSigned>, Option<Transaction>), HandleError> {
+	pub fn closing_signed(&mut self, fee_estimator: &FeeEstimator, msg: &msgs::ClosingSigned) -> Result<(Option<msgs::ClosingSigned>, Option<Transaction>), ChannelError> {
 		if self.channel_state & BOTH_SIDES_SHUTDOWN_MASK != BOTH_SIDES_SHUTDOWN_MASK {
-			return Err(HandleError{err: "Remote end sent us a closing_signed before both sides provided a shutdown", action: None});
+			return Err(ChannelError::Close("Remote end sent us a closing_signed before both sides provided a shutdown"));
 		}
 		if self.channel_state & (ChannelState::PeerDisconnected as u32) == ChannelState::PeerDisconnected as u32 {
-			return Err(HandleError{err: "Peer sent closing_signed when we needed a channel_reestablish", action: Some(msgs::ErrorAction::SendErrorMessage{msg: msgs::ErrorMessage{data: "Peer sent closing_signed when we needed a channel_reestablish".to_string(), channel_id: msg.channel_id}})});
+			return Err(ChannelError::Close("Peer sent closing_signed when we needed a channel_reestablish"));
 		}
 		if !self.pending_inbound_htlcs.is_empty() || !self.pending_outbound_htlcs.is_empty() {
-			return Err(HandleError{err: "Remote end sent us a closing_signed while there were still pending HTLCs", action: None});
+			return Err(ChannelError::Close("Remote end sent us a closing_signed while there were still pending HTLCs"));
 		}
 		if msg.fee_satoshis > 21000000 * 10000000 { //this is required to stop potential overflow in build_closing_transaction
-			return Err(HandleError{err: "Remote tried to send us a closing tx with > 21 million BTC fee", action: None});
+			return Err(ChannelError::Close("Remote tried to send us a closing tx with > 21 million BTC fee"));
 		}
 
 		let funding_redeemscript = self.get_funding_redeemscript();
 		let (mut closing_tx, used_total_fee) = self.build_closing_transaction(msg.fee_satoshis, false);
 		if used_total_fee != msg.fee_satoshis {
-			return Err(HandleError{err: "Remote sent us a closing_signed with a fee greater than the value they can claim", action: None});
+			return Err(ChannelError::Close("Remote sent us a closing_signed with a fee greater than the value they can claim"));
 		}
 		let mut sighash = Message::from_slice(&bip143::SighashComponents::new(&closing_tx).sighash_all(&closing_tx.input[0], &funding_redeemscript, self.channel_value_satoshis)[..]).unwrap();
 
@@ -2536,7 +2527,7 @@ impl Channel {
 				// limits, so check for that case by re-checking the signature here.
 				closing_tx = self.build_closing_transaction(msg.fee_satoshis, true).0;
 				sighash = Message::from_slice(&bip143::SighashComponents::new(&closing_tx).sighash_all(&closing_tx.input[0], &funding_redeemscript, self.channel_value_satoshis)[..]).unwrap();
-				secp_call!(self.secp_ctx.verify(&sighash, &msg.signature, &self.their_funding_pubkey.unwrap()), "Invalid closing tx signature from peer", self.channel_id());
+				secp_check!(self.secp_ctx.verify(&sighash, &msg.signature, &self.their_funding_pubkey.unwrap()), "Invalid closing tx signature from peer");
 			},
 		};
 
@@ -2570,7 +2561,7 @@ impl Channel {
 			if proposed_sat_per_kw > our_max_feerate {
 				if let Some((last_feerate, _)) = self.last_sent_closing_fee {
 					if our_max_feerate <= last_feerate {
-						return Err(HandleError{err: "Unable to come to consensus about closing feerate, remote wanted something higher than our Normal feerate", action: None});
+						return Err(ChannelError::Close("Unable to come to consensus about closing feerate, remote wanted something higher than our Normal feerate"));
 					}
 				}
 				propose_new_feerate!(our_max_feerate);
@@ -2580,7 +2571,7 @@ impl Channel {
 			if proposed_sat_per_kw < our_min_feerate {
 				if let Some((last_feerate, _)) = self.last_sent_closing_fee {
 					if our_min_feerate >= last_feerate {
-						return Err(HandleError{err: "Unable to come to consensus about closing feerate, remote wanted something lower than our Background feerate", action: None});
+						return Err(ChannelError::Close("Unable to come to consensus about closing feerate, remote wanted something lower than our Background feerate"));
 					}
 				}
 				propose_new_feerate!(our_min_feerate);
@@ -2780,7 +2771,7 @@ impl Channel {
 	/// In case of 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.
-	pub fn block_connected(&mut self, header: &BlockHeader, height: u32, txn_matched: &[&Transaction], indexes_of_txn_matched: &[u32]) -> Result<Option<msgs::FundingLocked>, HandleError> {
+	pub fn block_connected(&mut self, header: &BlockHeader, height: u32, txn_matched: &[&Transaction], indexes_of_txn_matched: &[u32]) -> Result<Option<msgs::FundingLocked>, msgs::ErrorMessage> {
 		let non_shutdown_state = self.channel_state & (!MULTI_STATE_FLAGS);
 		if header.bitcoin_hash() != self.last_block_connected {
 			self.last_block_connected = header.bitcoin_hash();
@@ -2840,7 +2831,10 @@ impl Channel {
 						}
 						self.channel_state = ChannelState::ShutdownComplete as u32;
 						self.channel_update_count += 1;
-						return Err(HandleError{err: "funding tx had wrong script/value", action: Some(ErrorAction::DisconnectPeer{msg: None})});
+						return Err(msgs::ErrorMessage {
+							channel_id: self.channel_id(),
+							data: "funding tx had wrong script/value".to_owned()
+						});
 					} else {
 						if self.channel_outbound {
 							for input in tx.input.iter() {
@@ -3160,7 +3154,7 @@ impl Channel {
 	}
 
 	/// Creates a signed commitment transaction to send to the remote peer.
-	/// Always returns a Channel-failing HandleError::action if an immediately-preceding (read: the
+	/// Always returns a ChannelError::Close if an immediately-preceding (read: the
 	/// last call to this Channel) send_htlc returned Ok(Some(_)) and there is an Err.
 	/// May panic if called except immediately after a successful, Ok(Some(_))-returning send_htlc.
 	pub fn send_commitment(&mut self) -> Result<(msgs::CommitmentSigned, ChannelMonitor), ChannelError> {

src/ln/channelmanager.rs

@@ -169,10 +169,6 @@ impl MsgHandleErrInternal {
 		}
 	}
 	#[inline]
-	fn from_maybe_close(err: msgs::HandleError) -> Self {
-		Self { err, needs_channel_force_close: true }
-	}
-	#[inline]
 	fn from_no_close(err: msgs::HandleError) -> Self {
 		Self { err, needs_channel_force_close: false }
 	}
@@ -1928,7 +1924,7 @@ impl ChannelManager {
 						//TODO: here and below MsgHandleErrInternal, #153 case
 						return Err(MsgHandleErrInternal::send_err_msg_no_close("Got a message for a channel from the wrong node!", msg.channel_id));
 					}
-					let (closing_signed, tx) = chan_entry.get_mut().closing_signed(&*self.fee_estimator, &msg).map_err(|e| MsgHandleErrInternal::from_maybe_close(e))?;
+					let (closing_signed, tx) = chan_entry.get_mut().closing_signed(&*self.fee_estimator, &msg).map_err(|e| MsgHandleErrInternal::from_chan_maybe_close(e, msg.channel_id))?;
 					if let Some(msg) = closing_signed {
 						channel_state.pending_msg_events.push(events::MessageSendEvent::SendClosingSigned {
 							node_id: their_node_id.clone(),
@@ -2005,7 +2001,7 @@ impl ChannelManager {
 						}));
 					}
 				}
-				chan.update_add_htlc(&msg, pending_forward_info).map_err(|e| MsgHandleErrInternal::from_maybe_close(e))
+				chan.update_add_htlc(&msg, pending_forward_info).map_err(|e| MsgHandleErrInternal::from_chan_maybe_close(e, msg.channel_id))
 			},
 			None => return Err(MsgHandleErrInternal::send_err_msg_no_close("Failed to find corresponding channel", msg.channel_id))
 		}
@@ -2588,11 +2584,9 @@ impl ChainListener for ChannelManager {
 				} else if let Err(e) = chan_res {
 					pending_msg_events.push(events::MessageSendEvent::HandleError {
 						node_id: channel.get_their_node_id(),
-						action: e.action,
+						action: Some(msgs::ErrorAction::SendErrorMessage { msg: e }),
 					});
-					if channel.is_shutdown() {
-						return false;
-					}
+					return false;
 				}
 				if let Some(funding_txo) = channel.get_funding_txo() {
 					for tx in txn_matched {
@@ -5532,7 +5526,7 @@ mod tests {
 					HandleError{err, .. } => assert_eq!(err, "Remote HTLC add would put them over their reserve value"),
 				}
 				// If we send a garbage message, the channel should get closed, making the rest of this test case fail.
-				/*assert_eq!(nodes[1].node.list_channels().len(), 1);
+				assert_eq!(nodes[1].node.list_channels().len(), 1);
 				assert_eq!(nodes[1].node.list_channels().len(), 1);
 				let channel_close_broadcast = nodes[1].node.get_and_clear_pending_msg_events();
 				assert_eq!(channel_close_broadcast.len(), 1);
@@ -5541,7 +5535,7 @@ mod tests {
 						assert_eq!(msg.contents.flags & 2, 2);
 					},
 					_ => panic!("Unexpected event"),
-				}*/
+				}
 				return;
 			}
 		}