Add counterparty_node_id & channel_capacity to ChannelClosed

The current ChannelClosed event does not let
you know the counterparty during a channel close
event. This change adds the counterparty_node_id
and the channel_capacity to the ChannelClosed event.
This helps users to have more context during a
channel close event. Solves #2343

Author: vladimirfomene

lightning/src/events/mod.rs

@@ -750,7 +750,12 @@ pub enum Event {
 		/// [`UserConfig::manually_accept_inbound_channels`]: crate::util::config::UserConfig::manually_accept_inbound_channels
 		user_channel_id: u128,
 		/// The reason the channel was closed.
-		reason: ClosureReason
+		reason: ClosureReason,
+		/// Counterparty in the closed channel.
+		counterparty_node_id: Option<PublicKey>,
+		/// Value of the closing channel (sats).
+		channel_capacity: Option<u64>,
+
 	},
 	/// Used to indicate to the user that they can abandon the funding transaction and recycle the
 	/// inputs for another purpose.
@@ -951,7 +956,7 @@ impl Writeable for Event {
 					(5, outbound_amount_forwarded_msat, option),
 				});
 			},
-			&Event::ChannelClosed { ref channel_id, ref user_channel_id, ref reason } => {
+			&Event::ChannelClosed { ref channel_id, ref user_channel_id, ref reason, ref counterparty_node_id, ref channel_capacity } => {
 				9u8.write(writer)?;
 				// `user_channel_id` used to be a single u64 value. In order to remain backwards
 				// compatible with versions prior to 0.0.113, the u128 is serialized as two
@@ -963,6 +968,8 @@ impl Writeable for Event {
 					(1, user_channel_id_low, required),
 					(2, reason, required),
 					(3, user_channel_id_high, required),
+					(5, counterparty_node_id, option),
+					(7, channel_capacity, option),
 				});
 			},
 			&Event::DiscardFunding { ref channel_id, ref transaction } => {
@@ -1245,11 +1252,15 @@ impl MaybeReadable for Event {
 					let mut reason = UpgradableRequired(None);
 					let mut user_channel_id_low_opt: Option<u64> = None;
 					let mut user_channel_id_high_opt: Option<u64> = None;
+					let mut counterparty_node_id = None;
+					let mut channel_capacity = None;
 					read_tlv_fields!(reader, {
 						(0, channel_id, required),
 						(1, user_channel_id_low_opt, option),
 						(2, reason, upgradable_required),
 						(3, user_channel_id_high_opt, option),
+						(5, counterparty_node_id, option),
+						(7, channel_capacity, option),
 					});
 
 					// `user_channel_id` used to be a single u64 value. In order to remain
@@ -1258,7 +1269,8 @@ impl MaybeReadable for Event {
 					let user_channel_id = (user_channel_id_low_opt.unwrap_or(0) as u128) +
 						((user_channel_id_high_opt.unwrap_or(0) as u128) << 64);
 
-					Ok(Some(Event::ChannelClosed { channel_id, user_channel_id, reason: _init_tlv_based_struct_field!(reason, upgradable_required) }))
+					Ok(Some(Event::ChannelClosed { channel_id, user_channel_id, reason: _init_tlv_based_struct_field!(reason, upgradable_required),
+						counterparty_node_id, channel_capacity }))
 				};
 				f()
 			},

lightning/src/ln/channelmanager.rs

@@ -1665,7 +1665,9 @@ macro_rules! handle_error {
 					if let Some((channel_id, user_channel_id)) = chan_id {
 						$self.pending_events.lock().unwrap().push_back((events::Event::ChannelClosed {
 							channel_id, user_channel_id,
-							reason: ClosureReason::ProcessingError { err: err.err.clone() }
+							reason: ClosureReason::ProcessingError { err: err.err.clone() },
+							counterparty_node_id: Some($counterparty_node_id),
+							channel_capacity: None,
 						}, None));
 					}
 				}
@@ -2359,7 +2361,9 @@ where
 		pending_events_lock.push_back((events::Event::ChannelClosed {
 			channel_id: context.channel_id(),
 			user_channel_id: context.get_user_id(),
-			reason: closure_reason
+			reason: closure_reason,
+			counterparty_node_id: Some(context.get_counterparty_node_id()),
+			channel_capacity: Some(context.get_value_satoshis()),
 		}, None));
 	}
 
@@ -8262,7 +8266,9 @@ where
 					channel_closures.push_back((events::Event::ChannelClosed {
 						channel_id: channel.context.channel_id(),
 						user_channel_id: channel.context.get_user_id(),
-						reason: ClosureReason::OutdatedChannelManager
+						reason: ClosureReason::OutdatedChannelManager,
+						counterparty_node_id: Some(channel.context.get_counterparty_node_id()),
+						channel_capacity: Some(channel.context.get_value_satoshis()),
 					}, None));
 					for (channel_htlc_source, payment_hash) in channel.inflight_htlc_sources() {
 						let mut found_htlc = false;
@@ -8314,6 +8320,9 @@ where
 					channel_id: channel.context.channel_id(),
 					user_channel_id: channel.context.get_user_id(),
 					reason: ClosureReason::DisconnectedPeer,
+					counterparty_node_id: Some(channel.context.get_counterparty_node_id()),
+					channel_capacity: Some(channel.context.get_value_satoshis()),
+
 				}, None));
 			} else {
 				log_error!(args.logger, "Missing ChannelMonitor for channel {} needed by ChannelManager.", log_bytes!(channel.context.channel_id()));