Include pending HTLCs in ChannelDetails

fuzz/src/router.rs

@@ -241,6 +241,8 @@ pub fn do_test<Out: test_logger::Output>(data: &[u8], out: Out) {
 							config: None,
 							feerate_sat_per_1000_weight: None,
 							channel_shutdown_state: Some(channelmanager::ChannelShutdownState::NotShuttingDown),
+							pending_inbound_htlcs: Vec::new(),
+							pending_outbound_htlcs: Vec::new(),
 						});
 					}
 					Some(&$first_hops_vec[..])

lightning/src/ln/channel.rs

@@ -152,6 +152,85 @@ enum InboundHTLCState {
 	LocalRemoved(InboundHTLCRemovalReason),
 }
 
+/// Exposes the state of pending inbound HTLCs.
+///
+/// Fail and fulfill suffixes indicate the resolution of the HTLC.
+#[derive(Clone, Debug, PartialEq)]
+pub enum InboundHTLCStateDetails {
+	/// RemoteAnnounced states indicate that the remote sent update_add_htlc for this HTLC while the
+	/// HTLC is not on any commitment transactions yet. It will be included in the next local
+	/// commitment transaction when we receive commitment_signed and return revoke_and_ack.
+	RemoteAnnouncedForward,
+	/// See above.
+	RemoteAnnouncedFail,
+	/// AwaitingRemoteRevokeToAnnounce states indicate that we have received commitment_signed with
+	/// this HTLC, returned revoke_and_ack, and this HTLC is included on the local commitment
+	/// transaction but not the remote commitment transaction. The remote hasn't yet revoked their
+	/// previous state and we have not yet included this HTLC in commitment_signed because we are
+	/// waiting on the remote's revocation.
+	AwaitingRemoteRevokeToAnnounceForward,
+	/// See above.
+	AwaitingRemoteRevokeToAnnounceFail,
+	/// AwaitingAnnouncedRemoteRevoke states indicate that we have received commitment_signed with
+	/// this HTLC, returned revoke_and_ack, and this HTLC is included on the local commitment
+	/// transaction. We have also included this HTLC in our latest commitment_signed and are now just
+	/// waiting on the remote's revoke_and_ack before this HTLC will be included on the remote
+	/// commitment transaction as well and can then get forwarded and/or removed.
+	AwaitingAnnouncedRemoteRevokeForward,
+	/// See above.
+	AwaitingAnnouncedRemoteRevokeFail,
+	/// Committed indicates that this HTLC has been included in the commitment_signed and
+	/// revoke_and_ack flow on both sides and is included in both commitment transactions.
+	Committed,
+	/// AwaitingRemoteRevokeToRemove states indicate that this HTLC will be removed by us sending
+	/// update_*_htlc and commitment_signed, but the remote has not sent revoke_and_ack for the
+	/// previous commitment_signed yet. The HTLC is still on both commitment transactions.
+	AwaitingRemoteRevokeToRemoveFulfill,
+	/// See above.
+	AwaitingRemoteRevokeToRemoveFail,
+	/// LocalRemoved states indicate that this HTLC has been removed by us and a new
+	/// commitment_signed was sent, but the HTLC is still on both commitment transactions. When the
+	/// remote sends the next revoke_and_ack, it will be removed from the remote's commitment
+	/// transaction.
+	LocalRemovedFailRelay,
+	/// See above.
+	LocalRemovedFailMalformed,
+	/// See above.
+	LocalRemovedFulfill,
+}
+
+impl From<&InboundHTLCState> for InboundHTLCStateDetails {
+	fn from(state: &InboundHTLCState) -> InboundHTLCStateDetails {
+		match state {
+			InboundHTLCState::RemoteAnnounced(PendingHTLCStatus::Forward(_)) => InboundHTLCStateDetails::RemoteAnnouncedForward,
+			InboundHTLCState::RemoteAnnounced(PendingHTLCStatus::Fail(_)) => InboundHTLCStateDetails::RemoteAnnouncedFail,
+			InboundHTLCState::AwaitingRemoteRevokeToAnnounce(PendingHTLCStatus::Forward(_)) => InboundHTLCStateDetails::AwaitingRemoteRevokeToAnnounceForward,
+			InboundHTLCState::AwaitingRemoteRevokeToAnnounce(PendingHTLCStatus::Fail(_)) => InboundHTLCStateDetails::AwaitingRemoteRevokeToAnnounceFail,
+			InboundHTLCState::AwaitingAnnouncedRemoteRevoke(PendingHTLCStatus::Forward(_)) => InboundHTLCStateDetails::AwaitingAnnouncedRemoteRevokeForward,
+			InboundHTLCState::AwaitingAnnouncedRemoteRevoke(PendingHTLCStatus::Fail(_)) => InboundHTLCStateDetails::AwaitingAnnouncedRemoteRevokeFail,
+			InboundHTLCState::Committed => InboundHTLCStateDetails::Committed,
+			InboundHTLCState::LocalRemoved(InboundHTLCRemovalReason::FailRelay(_)) => InboundHTLCStateDetails::LocalRemovedFailRelay,
+			InboundHTLCState::LocalRemoved(InboundHTLCRemovalReason::FailMalformed(_)) => InboundHTLCStateDetails::LocalRemovedFailMalformed,
+			InboundHTLCState::LocalRemoved(InboundHTLCRemovalReason::Fulfill(_)) => InboundHTLCStateDetails::LocalRemovedFulfill,
+		}
+	}
+}
+
+impl_writeable_tlv_based_enum!(InboundHTLCStateDetails,
+	(0, RemoteAnnouncedForward) => {},
+	(2, RemoteAnnouncedFail) => {},
+	(4, AwaitingRemoteRevokeToAnnounceForward) => {},
+	(6, AwaitingRemoteRevokeToAnnounceFail) => {},
+	(8, AwaitingAnnouncedRemoteRevokeForward) => {},
+	(10, AwaitingAnnouncedRemoteRevokeFail) => {},
+	(12, Committed) => {},
+	(14, AwaitingRemoteRevokeToRemoveFulfill) => {},
+	(16, AwaitingRemoteRevokeToRemoveFail) => {},
+	(18, LocalRemovedFailRelay) => {},
+	(20, LocalRemovedFailMalformed) => {},
+	(22, LocalRemovedFulfill) => {};
+);
+
 struct InboundHTLCOutput {
 	htlc_id: u64,
 	amount_msat: u64,
@@ -160,6 +239,35 @@ struct InboundHTLCOutput {
 	state: InboundHTLCState,
 }
 
+/// Exposes details around pending inbound HTLCs.
+#[derive(Clone, Debug, PartialEq)]
+pub struct InboundHTLCDetails {
+	/// The corresponding HTLC ID.
+	pub htlc_id: u64,
+	/// The amount in msat.
+	pub amount_msat: u64,
+	/// The CLTV expiry.
+	pub cltv_expiry: u32,
+	/// The payment hash.
+	pub payment_hash: PaymentHash,
+	/// The state of the HTLC in the update_*_htlc, commitment_signed, revoke_and_ack flow.
+	/// Informs on which commitment transactions the HTLC is included.
+	pub state: InboundHTLCStateDetails,
+	/// Whether the HTLC has an output below the local dust limit. If so, the output will be trimmed
+	/// from the local commitment transaction and added to the commitment transaction fee.
+	/// This takes into account the second-stage HTLC transactions as well.
+	pub is_dust: bool,
+}
+
+impl_writeable_tlv_based!(InboundHTLCDetails, {
+	(0, htlc_id, required),
+	(2, amount_msat, required),
+	(4, cltv_expiry, required),
+	(6, payment_hash, required),
+	(8, state, required),
+	(10, is_dust, required),
+});
+
 enum OutboundHTLCState {
 	/// Added by us and included in a commitment_signed (if we were AwaitingRemoteRevoke when we
 	/// created it we would have put it in the holding cell instead). When they next revoke_and_ack
@@ -192,6 +300,82 @@ enum OutboundHTLCState {
 	AwaitingRemovedRemoteRevoke(OutboundHTLCOutcome),
 }
 
+/// Exposes the state of pending outbound HTLCs.
+///
+/// Failure and success suffixes indicate the resolution of the HTLC.
+#[derive(Clone, Debug, PartialEq)]
+pub enum OutboundHTLCStateDetails {
+	/// THe AwaitingRemoteRevokeToAnnounce state indicates that this HTLC will be added by us sending
+	/// update_add_htlc and commitment_signed, but the remote has not sent revoke_and_ack for the
+	/// previous commitment_signed yet. The HTLC is not on any commitment transactions yet.
+	AwaitingRemoteRevokeToAnnounce,
+	/// The LocalAnnounced state indicates that this HTLC has been added by us and included in a
+	/// commitment_signed, but the HTLC is not on any commitment transactions yet. When the remote
+	/// sends the next revoke_and_ack, it will be included in the remote's commitment transaction.
+	LocalAnnounced,
+	/// The Committed state indicates that this HTLC has been included in a commitment_signed sent by
+	/// us and we have received a corresponding revoke_and_ack. The HTLC is therefore included in the
+	/// remote's commitment transaction. Note that this includes the subsequent state where we
+	/// receive the remote's commitment_signed with this HTLC, respond with the corresponding
+	/// revoke_and_ack, and include it in the local commitment transaction, as:
+	///  * they've revoked, so worst case we can announce an old state and get our (option on)
+	///    money back (though we won't), and,
+	///  * we'll send them a revoke when they send a commitment_signed, and since only they're
+	///    allowed to remove it, the "can only be removed once committed on both sides" requirement
+	///    doesn't matter to us and it's up to them to enforce it, worst-case they jump ahead but
+	///    we'll never get out of sync).
+	Committed,
+	/// RemoteRemoved states indicate that this HTLC has been removed by the remote with
+	/// update_*_htlc. The HTLC is still on both commitment transactions and we are waiting on their
+	/// commitment_signed mesage.
+	RemoteRemovedSuccess,
+	/// See above.
+	RemoteRemovedFailure,
+	/// AwaitingRemoteRevokeToRemove states indicate that the remote removed this HTLC and sent a
+	/// commitment_signed and we've revoke_and_ack'ed it. It is removed from the local commitment
+	/// transaction but the remote side hasn't yet revoked their previous state and therefore we
+	/// haven't yet removed this HTLC in our latest commitment_signed. This HTLC is still included in
+	/// the remote's commitment transaction.
+	AwaitingRemoteRevokeToRemoveSuccess,
+	/// See above.
+	AwaitingRemoteRevokeToRemoveFailure,
+	/// AwaitingRemovedRemoteRevoke states indicate that the remote removed this and sent a
+	/// commitment_signed and we've revoke_and_ack'ed it. It is therefore removed from the local
+	/// commitment transaction. This HTLC has also been removed in our latest commitment_signed and
+	/// will be removed from the remote's commitment transaction when we receive their
+	/// revoke_and_ack, after which we can do any backwards failing.
+	AwaitingRemovedRemoteRevokeSuccess,
+	/// See above.
+	AwaitingRemovedRemoteRevokeFailure,
+}
+
+impl From<&OutboundHTLCState> for OutboundHTLCStateDetails {
+	fn from(state: &OutboundHTLCState) -> OutboundHTLCStateDetails {
+		match state {
+			OutboundHTLCState::LocalAnnounced(_) => OutboundHTLCStateDetails::LocalAnnounced,
+			OutboundHTLCState::Committed => OutboundHTLCStateDetails::Committed,
+			OutboundHTLCState::RemoteRemoved(OutboundHTLCOutcome::Success(_)) => OutboundHTLCStateDetails::RemoteRemovedSuccess,
+			OutboundHTLCState::RemoteRemoved(OutboundHTLCOutcome::Failure(_)) => OutboundHTLCStateDetails::RemoteRemovedFailure,
+			OutboundHTLCState::AwaitingRemoteRevokeToRemove(OutboundHTLCOutcome::Success(_)) => OutboundHTLCStateDetails::AwaitingRemoteRevokeToRemoveSuccess,
+			OutboundHTLCState::AwaitingRemoteRevokeToRemove(OutboundHTLCOutcome::Failure(_)) => OutboundHTLCStateDetails::AwaitingRemoteRevokeToRemoveFailure,
+			OutboundHTLCState::AwaitingRemovedRemoteRevoke(OutboundHTLCOutcome::Success(_)) => OutboundHTLCStateDetails::AwaitingRemovedRemoteRevokeSuccess,
+			OutboundHTLCState::AwaitingRemovedRemoteRevoke(OutboundHTLCOutcome::Failure(_)) => OutboundHTLCStateDetails::AwaitingRemovedRemoteRevokeFailure,
+		}
+	}
+}
+
+impl_writeable_tlv_based_enum!(OutboundHTLCStateDetails,
+	(0, AwaitingRemoteRevokeToAnnounce) => {},
+	(2, LocalAnnounced) => {},
+	(4, Committed) => {},
+	(6, RemoteRemovedSuccess) => {},
+	(8, RemoteRemovedFailure) => {},
+	(10, AwaitingRemoteRevokeToRemoveSuccess) => {},
+	(12, AwaitingRemoteRevokeToRemoveFailure) => {},
+	(14, AwaitingRemovedRemoteRevokeSuccess) => {},
+	(16, AwaitingRemovedRemoteRevokeFailure) => {};
+);
+
 #[derive(Clone)]
 enum OutboundHTLCOutcome {
 	/// LDK version 0.0.105+ will always fill in the preimage here.
@@ -227,6 +411,39 @@ struct OutboundHTLCOutput {
 	skimmed_fee_msat: Option<u64>,
 }
 
+/// Exposes details around pending outbound HTLCs.
+#[derive(Clone, Debug, PartialEq)]
+pub struct OutboundHTLCDetails {
+	/// The corresponding HTLC ID.
+	/// Not present when we are awaiting a remote revocation and the HTLC is not added yet.
+	pub htlc_id: Option<u64>,
+	/// The amount in msat.
+	pub amount_msat: u64,
+	/// The CLTV expiry.
+	pub cltv_expiry: u32,
+	/// The payment hash.
+	pub payment_hash: PaymentHash,
+	/// The state of the HTLC in the update_*_htlc, commitment_signed, revoke_and_ack flow.
+	/// Informs on which commitment transactions the HTLC is included.
+	pub state: OutboundHTLCStateDetails,
+	/// The extra fee being skimmed off the top of this HTLC.
+	pub skimmed_fee_msat: Option<u64>,
+	/// Whether the HTLC has an output below the local dust limit. If so, the output will be trimmed
+	/// from the local commitment transaction and added to the commitment transaction fee.
+	/// This takes into account the second-stage HTLC transactions as well.
+	pub is_dust: bool,
+}
+
+impl_writeable_tlv_based!(OutboundHTLCDetails, {
+	(0, htlc_id, required),
+	(2, amount_msat, required),
+	(4, cltv_expiry, required),
+	(6, payment_hash, required),
+	(8, state, required),
+	(10, skimmed_fee_msat, required),
+	(12, is_dust, required),
+});
+
 /// See AwaitingRemoteRevoke ChannelState for more info
 enum HTLCUpdateAwaitingACK {
 	AddHTLC { // TODO: Time out if we're getting close to cltv_expiry
@@ -1549,6 +1766,90 @@ impl<Signer: ChannelSigner> ChannelContext<Signer> {
 		stats
 	}
 
+	/// Returns information on all pending inbound HTLCs.
+	pub fn get_pending_inbound_htlc_details(&self) -> Vec<InboundHTLCDetails> {
+		let mut holding_cell_states = HashMap::new();
+		for holding_cell_update in self.holding_cell_htlc_updates.iter() {
+			match holding_cell_update {
+				HTLCUpdateAwaitingACK::ClaimHTLC { htlc_id, .. } => {
+					holding_cell_states.insert(
+						htlc_id,
+						InboundHTLCStateDetails::AwaitingRemoteRevokeToRemoveFulfill,
+					);
+				},
+				HTLCUpdateAwaitingACK::FailHTLC { htlc_id, .. } => {
+					holding_cell_states.insert(
+						htlc_id,
+						InboundHTLCStateDetails::AwaitingRemoteRevokeToRemoveFail,
+					);
+				},
+				_ => {},
+			}
+		}
+		let mut inbound_details = Vec::new();
+		let htlc_success_dust_limit = if self.get_channel_type().supports_anchors_zero_fee_htlc_tx() {
+			0
+		} else {
+			let dust_buffer_feerate = self.get_dust_buffer_feerate(None) as u64;
+			dust_buffer_feerate * htlc_success_tx_weight(self.get_channel_type()) / 1000
+		};
+		let holder_dust_limit_success_sat = htlc_success_dust_limit + self.holder_dust_limit_satoshis;
+		for htlc in self.pending_inbound_htlcs.iter() {
+			inbound_details.push(InboundHTLCDetails{
+				htlc_id: htlc.htlc_id,
+				amount_msat: htlc.amount_msat,
+				cltv_expiry: htlc.cltv_expiry,
+				payment_hash: htlc.payment_hash,
+				state: holding_cell_states.remove(&htlc.htlc_id).unwrap_or((&htlc.state).into()),
+				is_dust: htlc.amount_msat / 1000 < holder_dust_limit_success_sat,
+			});
+		}
+		inbound_details
+	}
+
+	/// Returns information on all pending outbound HTLCs.
+	pub fn get_pending_outbound_htlc_details(&self) -> Vec<OutboundHTLCDetails> {
+		let mut outbound_details = Vec::new();
+		let htlc_timeout_dust_limit = if self.get_channel_type().supports_anchors_zero_fee_htlc_tx() {
+			0
+		} else {
+			let dust_buffer_feerate = self.get_dust_buffer_feerate(None) as u64;
+			dust_buffer_feerate * htlc_success_tx_weight(self.get_channel_type()) / 1000
+		};
+		let holder_dust_limit_timeout_sat = htlc_timeout_dust_limit + self.holder_dust_limit_satoshis;
+		for htlc in self.pending_outbound_htlcs.iter() {
+			outbound_details.push(OutboundHTLCDetails{
+				htlc_id: Some(htlc.htlc_id),
+				amount_msat: htlc.amount_msat,
+				cltv_expiry: htlc.cltv_expiry,
+				payment_hash: htlc.payment_hash,
+				skimmed_fee_msat: htlc.skimmed_fee_msat,
+				state: (&htlc.state).into(),
+				is_dust: htlc.amount_msat / 1000 < holder_dust_limit_timeout_sat,
+			});
+		}
+		for holding_cell_update in self.holding_cell_htlc_updates.iter() {
+			if let HTLCUpdateAwaitingACK::AddHTLC {
+				amount_msat,
+				cltv_expiry,
+				payment_hash,
+				skimmed_fee_msat,
+				..
+			} = *holding_cell_update {
+				outbound_details.push(OutboundHTLCDetails{
+					htlc_id: None,
+					amount_msat: amount_msat,
+					cltv_expiry: cltv_expiry,
+					payment_hash: payment_hash,
+					skimmed_fee_msat: skimmed_fee_msat,
+					state: OutboundHTLCStateDetails::AwaitingRemoteRevokeToAnnounce,
+					is_dust: amount_msat / 1000 < holder_dust_limit_timeout_sat,
+				});
+			}
+		}
+		outbound_details
+	}
+
 	/// Returns a HTLCStats about pending outbound htlcs, *including* pending adds in our holding cell.
 	fn get_outbound_pending_htlc_stats(&self, outbound_feerate_update: Option<u32>) -> HTLCStats {
 		let context = self;