Allowing user-specified error message during force close channel

In this commit i added additional parameter `error_message`  to `force_close_sending_error`,
that will allow users to configure error message and send to peers during force closing of channel.
I have also updated the tests for this updated function.

Author: Sharmalm

fuzz/src/full_stack.rs

@@ -734,9 +734,10 @@ pub fn do_test(mut data: &[u8], logger: &Arc<dyn Logger>) {
 			14 => {
 				let mut channels = channelmanager.list_channels();
 				let channel_id = get_slice!(1)[0] as usize;
+				let error_message = "Channel force-closed";
 				if channel_id >= channels.len() { return; }
 				channels.sort_by(|a, b| { a.channel_id.cmp(&b.channel_id) });
-				channelmanager.force_close_broadcasting_latest_txn(&channels[channel_id].channel_id, &channels[channel_id].counterparty.node_id).unwrap();
+				channelmanager.force_close_broadcasting_latest_txn(&channels[channel_id].channel_id, &channels[channel_id].counterparty.node_id, error_message.to_string()).unwrap();
 			},
 			// 15, 16, 17, 18 is above
 			19 => {

lightning-background-processor/src/lib.rs

@@ -1415,7 +1415,8 @@ mod tests {
 		}
 
 		// Force-close the channel.
-		nodes[0].node.force_close_broadcasting_latest_txn(&ChannelId::v1_from_funding_outpoint(OutPoint { txid: tx.txid(), index: 0 }), &nodes[1].node.get_our_node_id()).unwrap();
+		let error_message = "Channel force-closed";
+		nodes[0].node.force_close_broadcasting_latest_txn(&ChannelId::v1_from_funding_outpoint(OutPoint { txid: tx.txid(), index: 0 }), &nodes[1].node.get_our_node_id(), error_message.to_string()).unwrap();
 
 		// Check that the force-close updates are persisted.
 		check_persisted_data!(nodes[0].node, filepath.clone());
@@ -1608,7 +1609,8 @@ mod tests {
 		let bg_processor = BackgroundProcessor::start(persister, event_handler, nodes[0].chain_monitor.clone(), nodes[0].node.clone(), nodes[0].no_gossip_sync(), nodes[0].peer_manager.clone(), nodes[0].logger.clone(), Some(nodes[0].scorer.clone()));
 
 		// Force close the channel and check that the SpendableOutputs event was handled.
-		nodes[0].node.force_close_broadcasting_latest_txn(&nodes[0].node.list_channels()[0].channel_id, &nodes[1].node.get_our_node_id()).unwrap();
+		let error_message = "Channel force-closed";
+		nodes[0].node.force_close_broadcasting_latest_txn(&nodes[0].node.list_channels()[0].channel_id, &nodes[1].node.get_our_node_id(), error_message.to_string()).unwrap();
 		let commitment_tx = nodes[0].tx_broadcaster.txn_broadcasted.lock().unwrap().pop().unwrap();
 		confirm_transaction_depth(&mut nodes[0], &commitment_tx, BREAKDOWN_TIMEOUT as u32);
 

lightning-persister/src/fs_store.rs

@@ -446,7 +446,8 @@ mod tests {
 		let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
 		let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
 		let chan = create_announced_chan_between_nodes(&nodes, 0, 1);
-		nodes[1].node.force_close_broadcasting_latest_txn(&chan.2, &nodes[0].node.get_our_node_id()).unwrap();
+		let error_message = "Channel force-closed";
+		nodes[1].node.force_close_broadcasting_latest_txn(&chan.2, &nodes[0].node.get_our_node_id(), error_message.to_string()).unwrap();
 		check_closed_event!(nodes[1], 1, ClosureReason::HolderForceClosed, [nodes[0].node.get_our_node_id()], 100000);
 		let mut added_monitors = nodes[1].chain_monitor.added_monitors.lock().unwrap();
 		let update_map = nodes[1].chain_monitor.latest_monitor_update_id.lock().unwrap();
@@ -485,7 +486,8 @@ mod tests {
 		let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
 		let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
 		let chan = create_announced_chan_between_nodes(&nodes, 0, 1);
-		nodes[1].node.force_close_broadcasting_latest_txn(&chan.2, &nodes[0].node.get_our_node_id()).unwrap();
+		let error_message = "Channel force-closed";
+		nodes[1].node.force_close_broadcasting_latest_txn(&chan.2, &nodes[0].node.get_our_node_id(), error_message.to_string()).unwrap();
 		check_closed_event!(nodes[1], 1, ClosureReason::HolderForceClosed, [nodes[0].node.get_our_node_id()], 100000);
 		let mut added_monitors = nodes[1].chain_monitor.added_monitors.lock().unwrap();
 		let update_map = nodes[1].chain_monitor.latest_monitor_update_id.lock().unwrap();

lightning-persister/src/test_utils.rs

@@ -104,7 +104,8 @@ pub(crate) fn do_test_store<K: KVStore>(store_0: &K, store_1: &K) {
 
 	// Force close because cooperative close doesn't result in any persisted
 	// updates.
-	nodes[0].node.force_close_broadcasting_latest_txn(&nodes[0].node.list_channels()[0].channel_id, &nodes[1].node.get_our_node_id()).unwrap();
+	let error_message = "Channel force-closed";
+	nodes[0].node.force_close_broadcasting_latest_txn(&nodes[0].node.list_channels()[0].channel_id, &nodes[1].node.get_our_node_id(), error_message.to_string()).unwrap();
 	check_closed_event!(nodes[0], 1, ClosureReason::HolderForceClosed, [nodes[1].node.get_our_node_id()], 100000);
 	check_closed_broadcast!(nodes[0], true);
 	check_added_monitors!(nodes[0], 1);

lightning/src/ln/async_signer_tests.rs

@@ -363,12 +363,13 @@ fn do_test_async_holder_signatures(anchors: bool, remote_commitment: bool) {
 	// Route an HTLC and set the signer as unavailable.
 	let (_, _, chan_id, funding_tx) = create_announced_chan_between_nodes(&nodes, 0, 1);
 	route_payment(&nodes[0], &[&nodes[1]], 1_000_000);
+	let error_message = "Channel force-closed";
 
 	nodes[0].set_channel_signer_available(&nodes[1].node.get_our_node_id(), &chan_id, false);
 
 	if remote_commitment {
 		// Make the counterparty broadcast its latest commitment.
-		nodes[1].node.force_close_broadcasting_latest_txn(&chan_id, &nodes[0].node.get_our_node_id()).unwrap();
+		nodes[1].node.force_close_broadcasting_latest_txn(&chan_id, &nodes[0].node.get_our_node_id(), error_message.to_string()).unwrap();
 		check_added_monitors(&nodes[1], 1);
 		check_closed_broadcast(&nodes[1], 1, true);
 		check_closed_event(&nodes[1], 1, ClosureReason::HolderForceClosed, false, &[nodes[0].node.get_our_node_id()], 100_000);

lightning/src/ln/blinded_payment_tests.rs

@@ -344,6 +344,7 @@ fn do_forward_fail_in_process_pending_htlc_fwds(check: ProcessPendingHTLCsCheck)
 	assert_eq!(events.len(), 1);
 	let ev = remove_first_msg_event_to_node(&nodes[1].node.get_our_node_id(), &mut events);
 	let mut payment_event = SendEvent::from_event(ev);
+	let error_message = "Channel force-closed";
 
 	nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &payment_event.msgs[0]);
 	check_added_monitors!(nodes[1], 0);
@@ -361,7 +362,7 @@ fn do_forward_fail_in_process_pending_htlc_fwds(check: ProcessPendingHTLCsCheck)
 		ProcessPendingHTLCsCheck::FwdChannelClosed => {
 			// Force close the next-hop channel so when we go to forward in process_pending_htlc_forwards,
 			// the intro node will error backwards.
-			nodes[1].node.force_close_broadcasting_latest_txn(&channel_id, &nodes[2].node.get_our_node_id()).unwrap();
+			nodes[1].node.force_close_broadcasting_latest_txn(&channel_id, &nodes[2].node.get_our_node_id(), error_message.to_string()).unwrap();
 			let events = nodes[1].node.get_and_clear_pending_events();
 			match events[0] {
 				crate::events::Event::PendingHTLCsForwardable { .. } => {},

lightning/src/ln/chanmon_update_fail_tests.rs

@@ -206,7 +206,8 @@ fn do_test_simple_monitor_temporary_update_fail(disconnect: bool) {
 	}
 
 	// ...and make sure we can force-close a frozen channel
-	nodes[0].node.force_close_broadcasting_latest_txn(&channel_id, &nodes[1].node.get_our_node_id()).unwrap();
+	let error_message = "Channel force-closed";
+	nodes[0].node.force_close_broadcasting_latest_txn(&channel_id, &nodes[1].node.get_our_node_id(), error_message.to_string()).unwrap();
 	check_added_monitors!(nodes[0], 1);
 	check_closed_broadcast!(nodes[0], true);
 
@@ -3221,17 +3222,18 @@ fn do_test_durable_preimages_on_closed_channel(close_chans_before_reload: bool,
 	let _ = get_revoke_commit_msgs!(nodes[1], nodes[2].node.get_our_node_id());
 
 	let mon_bc = get_monitor!(nodes[1], chan_id_bc).encode();
+	let error_message = "Channel force-closed";
 
 	if close_chans_before_reload {
 		if !close_only_a {
 			chanmon_cfgs[1].persister.set_update_ret(ChannelMonitorUpdateStatus::InProgress);
-			nodes[1].node.force_close_broadcasting_latest_txn(&chan_id_bc, &nodes[2].node.get_our_node_id()).unwrap();
+			nodes[1].node.force_close_broadcasting_latest_txn(&chan_id_bc, &nodes[2].node.get_our_node_id(), error_message.to_string()).unwrap();
 			check_closed_broadcast(&nodes[1], 1, true);
 			check_closed_event(&nodes[1], 1, ClosureReason::HolderForceClosed, false, &[nodes[2].node.get_our_node_id()], 100000);
 		}
 
 		chanmon_cfgs[1].persister.set_update_ret(ChannelMonitorUpdateStatus::InProgress);
-		nodes[1].node.force_close_broadcasting_latest_txn(&chan_id_ab, &nodes[0].node.get_our_node_id()).unwrap();
+		nodes[1].node.force_close_broadcasting_latest_txn(&chan_id_ab, &nodes[0].node.get_our_node_id(), error_message.to_string()).unwrap();
 		check_closed_broadcast(&nodes[1], 1, true);
 		check_closed_event(&nodes[1], 1, ClosureReason::HolderForceClosed, false, &[nodes[0].node.get_our_node_id()], 100000);
 	}
@@ -3252,8 +3254,9 @@ fn do_test_durable_preimages_on_closed_channel(close_chans_before_reload: bool,
 			assert_eq!(bs_close_txn.len(), 3);
 		}
 	}
+	let error_message = "Channel force-closed";
 
-	nodes[0].node.force_close_broadcasting_latest_txn(&chan_id_ab, &nodes[1].node.get_our_node_id()).unwrap();
+	nodes[0].node.force_close_broadcasting_latest_txn(&chan_id_ab, &nodes[1].node.get_our_node_id(), error_message.to_string()).unwrap();
 	check_closed_event(&nodes[0], 1, ClosureReason::HolderForceClosed, false, &[nodes[1].node.get_our_node_id()], 100000);
 	let as_closing_tx = nodes[0].tx_broadcaster.txn_broadcasted.lock().unwrap().split_off(0);
 	assert_eq!(as_closing_tx.len(), 1);
@@ -3390,10 +3393,11 @@ fn do_test_reload_mon_update_completion_actions(close_during_reload: bool) {
 	let manager_b = nodes[1].node.encode();
 	reload_node!(nodes[1], &manager_b, &[&mon_ab, &mon_bc], persister, new_chain_monitor, nodes_1_deserialized);
 
+	let error_message = "Channel force-closed";
 	if close_during_reload {
 		// Test that we still free the B<->C channel if the A<->B channel closed while we reloaded
 		// (as learned about during the on-reload block connection).
-		nodes[0].node.force_close_broadcasting_latest_txn(&chan_id_ab, &nodes[1].node.get_our_node_id()).unwrap();
+		nodes[0].node.force_close_broadcasting_latest_txn(&chan_id_ab, &nodes[1].node.get_our_node_id(), error_message.to_string()).unwrap();
 		check_added_monitors!(nodes[0], 1);
 		check_closed_broadcast!(nodes[0], true);
 		check_closed_event(&nodes[0], 1, ClosureReason::HolderForceClosed, false, &[nodes[1].node.get_our_node_id()], 100_000);

lightning/src/ln/channelmanager.rs

@@ -2986,8 +2986,11 @@ where
 		Ok(counterparty_node_id)
 	}
 
-	fn force_close_sending_error(&self, channel_id: &ChannelId, counterparty_node_id: &PublicKey, broadcast: bool) -> Result<(), APIError> {
+	fn force_close_sending_error(&self, channel_id: &ChannelId, counterparty_node_id: &PublicKey, broadcast: bool, error_message: String) 
+	-> Result<(), APIError> {
 		let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
+		log_debug!(self.logger, 
+			"Force-closing channel, The error message sent to the peer : {}", error_message);
 		match self.force_close_channel_with_peer(channel_id, counterparty_node_id, None, broadcast) {
 			Ok(counterparty_node_id) => {
 				let per_peer_state = self.per_peer_state.read().unwrap();
@@ -2997,7 +3000,7 @@ where
 						events::MessageSendEvent::HandleError {
 							node_id: counterparty_node_id,
 							action: msgs::ErrorAction::DisconnectPeer {
-								msg: Some(msgs::ErrorMessage { channel_id: *channel_id, data: "Channel force-closed".to_owned() })
+								msg: Some(msgs::ErrorMessage { channel_id: *channel_id, data: error_message.to_owned() })
 							},
 						}
 					);
@@ -3008,13 +3011,13 @@ where
 		}
 	}
 
-	/// Force closes a channel, immediately broadcasting the latest local transaction(s) and
-	/// rejecting new HTLCs on the given channel. Fails if `channel_id` is unknown to
-	/// the manager, or if the `counterparty_node_id` isn't the counterparty of the corresponding
-	/// channel.
-	pub fn force_close_broadcasting_latest_txn(&self, channel_id: &ChannelId, counterparty_node_id: &PublicKey)
+	/// Force closes a channel, immediately broadcasting the latest local transaction(s),
+	/// rejecting new HTLCs and sending a `error message` String to the peer on the given channel.
+	/// Fails if `channel_id` is unknown to the manager, or if the `counterparty_node_id`
+	/// isn't the counterparty of the corresponding channel.
+	pub fn force_close_broadcasting_latest_txn(&self, channel_id: &ChannelId, counterparty_node_id: &PublicKey, error_message: String)
 	-> Result<(), APIError> {
-		self.force_close_sending_error(channel_id, counterparty_node_id, true)
+		self.force_close_sending_error(channel_id, counterparty_node_id, true, error_message)
 	}
 
 	/// Force closes a channel, rejecting new HTLCs on the given channel but skips broadcasting
@@ -3023,24 +3026,24 @@ where
 	///
 	/// You can always broadcast the latest local transaction(s) via
 	/// [`ChannelMonitor::broadcast_latest_holder_commitment_txn`].
-	pub fn force_close_without_broadcasting_txn(&self, channel_id: &ChannelId, counterparty_node_id: &PublicKey)
+	pub fn force_close_without_broadcasting_txn(&self, channel_id: &ChannelId, counterparty_node_id: &PublicKey, error_message: String)
 	-> Result<(), APIError> {
-		self.force_close_sending_error(channel_id, counterparty_node_id, false)
+		self.force_close_sending_error(channel_id, counterparty_node_id, false, error_message)
 	}
 
 	/// Force close all channels, immediately broadcasting the latest local commitment transaction
 	/// for each to the chain and rejecting new HTLCs on each.
-	pub fn force_close_all_channels_broadcasting_latest_txn(&self) {
+	pub fn force_close_all_channels_broadcasting_latest_txn(&self, error_message: String) {
 		for chan in self.list_channels() {
-			let _ = self.force_close_broadcasting_latest_txn(&chan.channel_id, &chan.counterparty.node_id);
+			let _ = self.force_close_broadcasting_latest_txn(&chan.channel_id, &chan.counterparty.node_id, error_message.clone());
 		}
 	}
 
 	/// Force close all channels rejecting new HTLCs on each but without broadcasting the latest
 	/// local transaction(s).
-	pub fn force_close_all_channels_without_broadcasting_txn(&self) {
+	pub fn force_close_all_channels_without_broadcasting_txn(&self, error_message: String) {
 		for chan in self.list_channels() {
-			let _ = self.force_close_without_broadcasting_txn(&chan.channel_id, &chan.counterparty.node_id);
+			let _ = self.force_close_without_broadcasting_txn(&chan.channel_id, &chan.counterparty.node_id, error_message.clone());
 		}
 	}
 
@@ -11739,8 +11742,8 @@ mod tests {
 
 		nodes[0].node.peer_disconnected(&nodes[1].node.get_our_node_id());
 		nodes[1].node.peer_disconnected(&nodes[0].node.get_our_node_id());
-
-		nodes[0].node.force_close_broadcasting_latest_txn(&chan.2, &nodes[1].node.get_our_node_id()).unwrap();
+		let error_message = "Channel force-closed";
+		nodes[0].node.force_close_broadcasting_latest_txn(&chan.2, &nodes[1].node.get_our_node_id(), error_message.to_string()).unwrap();
 		check_closed_broadcast!(nodes[0], true);
 		check_added_monitors!(nodes[0], 1);
 		check_closed_event!(nodes[0], 1, ClosureReason::HolderForceClosed, [nodes[1].node.get_our_node_id()], 100000);
@@ -11957,6 +11960,7 @@ mod tests {
 		let channel_id = ChannelId::from_bytes([4; 32]);
 		let unkown_public_key = PublicKey::from_secret_key(&Secp256k1::signing_only(), &SecretKey::from_slice(&[42; 32]).unwrap());
 		let intercept_id = InterceptId([0; 32]);
+		let error_message = "Channel force-closed";
 
 		// Test the API functions.
 		check_not_connected_to_peer_error(nodes[0].node.create_channel(unkown_public_key, 1_000_000, 500_000_000, 42, None, None), unkown_public_key);
@@ -11965,9 +11969,9 @@ mod tests {
 
 		check_unkown_peer_error(nodes[0].node.close_channel(&channel_id, &unkown_public_key), unkown_public_key);
 
-		check_unkown_peer_error(nodes[0].node.force_close_broadcasting_latest_txn(&channel_id, &unkown_public_key), unkown_public_key);
+		check_unkown_peer_error(nodes[0].node.force_close_broadcasting_latest_txn(&channel_id, &unkown_public_key, error_message.to_string()), unkown_public_key);
 
-		check_unkown_peer_error(nodes[0].node.force_close_without_broadcasting_txn(&channel_id, &unkown_public_key), unkown_public_key);
+		check_unkown_peer_error(nodes[0].node.force_close_without_broadcasting_txn(&channel_id, &unkown_public_key, error_message.to_string()), unkown_public_key);
 
 		check_unkown_peer_error(nodes[0].node.forward_intercepted_htlc(intercept_id, &channel_id, unkown_public_key, 1_000_000), unkown_public_key);
 
@@ -11989,15 +11993,16 @@ mod tests {
 
 		// Dummy values
 		let channel_id = ChannelId::from_bytes([4; 32]);
+		let error_message = "Channel force-closed";
 
 		// Test the API functions.
 		check_api_misuse_error(nodes[0].node.accept_inbound_channel(&channel_id, &counterparty_node_id, 42));
 
 		check_channel_unavailable_error(nodes[0].node.close_channel(&channel_id, &counterparty_node_id), channel_id, counterparty_node_id);
 
-		check_channel_unavailable_error(nodes[0].node.force_close_broadcasting_latest_txn(&channel_id, &counterparty_node_id), channel_id, counterparty_node_id);
+		check_channel_unavailable_error(nodes[0].node.force_close_broadcasting_latest_txn(&channel_id, &counterparty_node_id, error_message.to_string()), channel_id, counterparty_node_id);
 
-		check_channel_unavailable_error(nodes[0].node.force_close_without_broadcasting_txn(&channel_id, &counterparty_node_id), channel_id, counterparty_node_id);
+		check_channel_unavailable_error(nodes[0].node.force_close_without_broadcasting_txn(&channel_id, &counterparty_node_id, error_message.to_string()), channel_id, counterparty_node_id);
 
 		check_channel_unavailable_error(nodes[0].node.forward_intercepted_htlc(InterceptId([0; 32]), &channel_id, counterparty_node_id, 1_000_000), channel_id, counterparty_node_id);
 
@@ -12351,6 +12356,7 @@ mod tests {
 		anchors_config.manually_accept_inbound_channels = true;
 		let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[Some(anchors_config.clone()), Some(anchors_config.clone())]);
 		let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
+		let error_message = "Channel force-closed";
 
 		nodes[0].node.create_channel(nodes[1].node.get_our_node_id(), 100_000, 0, 0, None, None).unwrap();
 		let open_channel_msg = get_event_msg!(nodes[0], MessageSendEvent::SendOpenChannel, nodes[1].node.get_our_node_id());
@@ -12360,7 +12366,7 @@ mod tests {
 		let events = nodes[1].node.get_and_clear_pending_events();
 		match events[0] {
 			Event::OpenChannelRequest { temporary_channel_id, .. } => {
-				nodes[1].node.force_close_broadcasting_latest_txn(&temporary_channel_id, &nodes[0].node.get_our_node_id()).unwrap();
+				nodes[1].node.force_close_broadcasting_latest_txn(&temporary_channel_id, &nodes[0].node.get_our_node_id(), error_message.to_string()).unwrap();
 			}
 			_ => panic!("Unexpected event"),
 		}
@@ -12468,12 +12474,13 @@ mod tests {
 		let user_config = test_default_channel_config();
 		let node_chanmgr = create_node_chanmgrs(2, &node_cfg, &[Some(user_config), Some(user_config)]);
 		let nodes = create_network(2, &node_cfg, &node_chanmgr);
+		let error_message = "Channel force-closed";
 
 		// Open a channel, immediately disconnect each other, and broadcast Alice's latest state.
 		let (_, _, chan_id, funding_tx) = create_announced_chan_between_nodes(&nodes, 0, 1);
 		nodes[0].node.peer_disconnected(&nodes[1].node.get_our_node_id());
 		nodes[1].node.peer_disconnected(&nodes[0].node.get_our_node_id());
-		nodes[0].node.force_close_broadcasting_latest_txn(&chan_id, &nodes[1].node.get_our_node_id()).unwrap();
+		nodes[0].node.force_close_broadcasting_latest_txn(&chan_id, &nodes[1].node.get_our_node_id(), error_message.to_string()).unwrap();
 		check_closed_broadcast(&nodes[0], 1, true);
 		check_added_monitors(&nodes[0], 1);
 		check_closed_event!(nodes[0], 1, ClosureReason::HolderForceClosed, [nodes[1].node.get_our_node_id()], 100000);