Merge pull request #1203 from lightning-signer/2021-12-value-to-self

Getter for the total channel balance

Author: TheBlueMatt

fuzz/src/router.rs

@@ -223,6 +223,7 @@ pub fn do_test<Out: test_logger::Output>(data: &[u8], out: Out) {
 								force_close_spend_delay: None,
 								is_outbound: true, is_funding_locked: true,
 								is_usable: true, is_public: true,
+								balance_msat: 0,
 								outbound_capacity_msat: 0,
 							});
 						}

lightning/src/ln/channel.rs

@@ -2122,6 +2122,8 @@ impl<Signer: Sign> Channel<Signer> {
 	/// Doesn't bother handling the
 	/// if-we-removed-it-already-but-haven't-fully-resolved-they-can-still-send-an-inbound-HTLC
 	/// corner case properly.
+	/// The channel reserve is subtracted from each balance.
+	/// See also [`Channel::get_balance_msat`]
 	pub fn get_inbound_outbound_available_balance_msat(&self) -> (u64, u64) {
 		// Note that we have to handle overflow due to the above case.
 		(
@@ -2137,6 +2139,14 @@ impl<Signer: Sign> Channel<Signer> {
 		)
 	}
 
+	/// Get our total balance in msat.
+	/// This is the amount that would go to us if we close the channel, ignoring any on-chain fees.
+	/// See also [`Channel::get_inbound_outbound_available_balance_msat`]
+	pub fn get_balance_msat(&self) -> u64 {
+		self.value_to_self_msat
+			- self.get_outbound_pending_htlc_stats(None).pending_htlcs_value_msat
+	}
+
 	pub fn get_holder_counterparty_selected_channel_reserve_satoshis(&self) -> (u64, Option<u64>) {
 		(self.holder_selected_channel_reserve_satoshis, self.counterparty_selected_channel_reserve_satoshis)
 	}

lightning/src/ln/channelmanager.rs

@@ -868,17 +868,30 @@ pub struct ChannelDetails {
 	pub unspendable_punishment_reserve: Option<u64>,
 	/// The `user_channel_id` passed in to create_channel, or 0 if the channel was inbound.
 	pub user_channel_id: u64,
+	/// Our total balance.  This is the amount we would get if we close the channel.
+	/// This value is not exact. Due to various in-flight changes and feerate changes, exactly this
+	/// amount is not likely to be recoverable on close.
+	///
+	/// This does not include any pending HTLCs which are not yet fully resolved (and, thus, whose
+	/// balance is not available for inclusion in new outbound HTLCs). This further does not include
+	/// any pending outgoing HTLCs which are awaiting some other resolution to be sent.
+	/// This does not consider any on-chain fees.
+	///
+	/// See also [`ChannelDetails::outbound_capacity_msat`]
+	pub balance_msat: u64,
 	/// The available outbound capacity for sending HTLCs to the remote peer. This does not include
-	/// any pending HTLCs which are not yet fully resolved (and, thus, who's balance is not
+	/// any pending HTLCs which are not yet fully resolved (and, thus, whose balance is not
 	/// available for inclusion in new outbound HTLCs). This further does not include any pending
 	/// outgoing HTLCs which are awaiting some other resolution to be sent.
 	///
+	/// See also [`ChannelDetails::balance_msat`]
+	///
 	/// This value is not exact. Due to various in-flight changes, feerate changes, and our
 	/// conflict-avoidance policy, exactly this amount is not likely to be spendable. However, we
 	/// should be able to spend nearly this amount.
 	pub outbound_capacity_msat: u64,
 	/// The available inbound capacity for the remote peer to send HTLCs to us. This does not
-	/// include any pending HTLCs which are not yet fully resolved (and, thus, who's balance is not
+	/// include any pending HTLCs which are not yet fully resolved (and, thus, whose balance is not
 	/// available for inclusion in new inbound HTLCs).
 	/// Note that there are some corner cases not fully handled here, so the actual available
 	/// inbound capacity may be slightly higher than this.
@@ -1449,6 +1462,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 			res.reserve(channel_state.by_id.len());
 			for (channel_id, channel) in channel_state.by_id.iter().filter(f) {
 				let (inbound_capacity_msat, outbound_capacity_msat) = channel.get_inbound_outbound_available_balance_msat();
+				let balance_msat = channel.get_balance_msat();
 				let (to_remote_reserve_satoshis, to_self_reserve_satoshis) =
 					channel.get_holder_counterparty_selected_channel_reserve_satoshis();
 				res.push(ChannelDetails {
@@ -1463,6 +1477,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 					short_channel_id: channel.get_short_channel_id(),
 					channel_value_satoshis: channel.get_value_satoshis(),
 					unspendable_punishment_reserve: to_self_reserve_satoshis,
+					balance_msat,
 					inbound_capacity_msat,
 					outbound_capacity_msat,
 					user_channel_id: channel.get_user_id(),

lightning/src/routing/router.rs

@@ -1521,6 +1521,7 @@ mod tests {
 			short_channel_id,
 			channel_value_satoshis: 0,
 			user_channel_id: 0,
+			balance_msat: 0,
 			outbound_capacity_msat,
 			inbound_capacity_msat: 42,
 			unspendable_punishment_reserve: None,