rustfmt: move channel acceptance tests into own file and format

lightning/src/ln/chan_utils.rs

@@ -56,8 +56,13 @@ use crate::prelude::*;
 /// 483 for non-zero-fee-commitment channels and 114 for zero-fee-commitment channels.
 ///
 /// Actual maximums can be set equal to or below this value by each channel participant.
-pub fn max_htlcs(_channel_type: &ChannelTypeFeatures) -> u16 {
-	483
+pub fn max_htlcs(channel_type: &ChannelTypeFeatures) -> u16 {
+	if channel_type.supports_anchor_zero_fee_commitments() {
+		// TRUC restricts the size of our commitment transactions to 10K vB rather than 100K vB
+		114
+	} else {
+		483
+	}
 }
 /// The weight of a BIP141 witnessScript for a BOLT3's "offered HTLC output" on a commitment transaction, non-anchor variant.
 pub const OFFERED_HTLC_SCRIPT_WEIGHT: usize = 133;

lightning/src/ln/channel.rs

@@ -3036,12 +3036,18 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider {
 		debug_assert!(!channel_type.supports_any_optional_bits());
 		debug_assert!(!channel_type.requires_unknown_bits_from(&channelmanager::provided_channel_type_features(&config)));
 
-		let (commitment_conf_target, anchor_outputs_value_msat)  = if channel_type.supports_anchors_zero_fee_htlc_tx() {
-			(ConfirmationTarget::AnchorChannelFee, ANCHOR_OUTPUT_VALUE_SATOSHI * 2 * 1000)
-		} else {
-			(ConfirmationTarget::NonAnchorChannelFee, 0)
-		};
-		let commitment_feerate = fee_estimator.bounded_sat_per_1000_weight(commitment_conf_target);
+		let (commitment_feerate, anchor_outputs_value_msat) =
+			if channel_type.supports_anchor_zero_fee_commitments() {
+				(0, 0)
+			} else if channel_type.supports_anchors_zero_fee_htlc_tx() {
+				let feerate = fee_estimator
+					.bounded_sat_per_1000_weight(ConfirmationTarget::AnchorChannelFee);
+				(feerate, ANCHOR_OUTPUT_VALUE_SATOSHI * 2 * 1000)
+			} else {
+				let feerate = fee_estimator
+					.bounded_sat_per_1000_weight(ConfirmationTarget::NonAnchorChannelFee);
+				(feerate, 0)
+			};
 
 		let value_to_self_msat = channel_value_satoshis * 1000 - push_msat;
 		let commitment_tx_fee = commit_tx_fee_sat(commitment_feerate, MIN_AFFORDABLE_HTLC_COUNT, &channel_type) * 1000;
@@ -4860,7 +4866,16 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider {
 		// counterparty is advertising the feature, but rejecting channels proposing the feature for
 		// whatever reason.
 		let channel_type = &mut funding.channel_transaction_parameters.channel_type_features;
-		if channel_type.supports_anchors_zero_fee_htlc_tx() {
+		if channel_type.supports_anchor_zero_fee_commitments() {
+			channel_type.clear_anchor_zero_fee_commitments();
+			channel_type.set_anchors_zero_fee_htlc_tx_required();
+			channel_type.set_static_remote_key_required();
+
+			self.feerate_per_kw = fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::AnchorChannelFee);
+			assert!(!channel_type.supports_anchor_zero_fee_commitments());
+			assert!(channel_type.supports_anchors_zero_fee_htlc_tx());
+			assert!(channel_type.supports_static_remote_key());
+		} else if channel_type.supports_anchors_zero_fee_htlc_tx() {
 			channel_type.clear_anchors_zero_fee_htlc_tx();
 			self.feerate_per_kw = fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::NonAnchorChannelFee);
 			assert!(!channel_type.supports_anchors_nonzero_fee_htlc_tx());
@@ -5223,6 +5238,15 @@ impl<SP: Deref> FundedChannel<SP> where
 		feerate_per_kw: u32, cur_feerate_per_kw: Option<u32>, logger: &L
 	) -> Result<(), ChannelError> where F::Target: FeeEstimator, L::Target: Logger,
 	{
+		if channel_type.supports_anchor_zero_fee_commitments() {
+			if feerate_per_kw != 0 {
+				let err = "Zero Fee Channels must never attempt to use a fee".to_owned();
+				return Err(ChannelError::close(err));
+			} else {
+				return Ok(());
+			}
+		}
+
 		let lower_limit_conf_target = if channel_type.supports_anchors_zero_fee_htlc_tx() {
 			ConfirmationTarget::MinAllowedAnchorChannelRemoteFee
 		} else {
@@ -9906,8 +9930,9 @@ pub(super) fn channel_type_from_open_channel(
 
 		// We only support the channel types defined by the `ChannelManager` in
 		// `provided_channel_type_features`. The channel type must always support
-		// `static_remote_key`.
-		if !channel_type.requires_static_remote_key() {
+		// `static_remote_key`, except for `option_zero_fee_commitments` which
+		// assumes this feature.
+		if !channel_type.requires_static_remote_key() && !channel_type.requires_anchor_zero_fee_commitments(){
 			return Err(ChannelError::close("Channel Type was not understood - we require static remote key".to_owned()));
 		}
 		// Make sure we support all of the features behind the channel type.
@@ -10492,10 +10517,21 @@ fn get_initial_channel_type(config: &UserConfig, their_features: &InitFeatures)
 		ret.set_scid_privacy_required();
 	}
 
-	// Optionally, if the user would like to negotiate the `anchors_zero_fee_htlc_tx` option, we
-	// set it now. If they don't understand it, we'll fall back to our default of
-	// `only_static_remotekey`.
-	if config.channel_handshake_config.negotiate_anchors_zero_fee_htlc_tx &&
+	// Optionally, if the user would like to negotiate `option_zero_fee_commitments` we set it now.
+	// If they don't understand it (or we don't want it), we check the same conditions for
+	// `option_anchors_zero_fee_htlc_tx`. The counterparty can still refuse the channel and we'll
+	// try to fall back (all the way to `only_static_remotekey`).
+	#[cfg(not(test))]
+	let negotiate_zero_fee_commitments = false;
+
+	#[cfg(test)]
+	let negotiate_zero_fee_commitments = config.channel_handshake_config.negotiate_anchor_zero_fee_commitments;
+
+	if negotiate_zero_fee_commitments && their_features.supports_anchor_zero_fee_commitments() {
+		ret.set_anchor_zero_fee_commitments_required();
+		// `option_static_remote_key` is assumed by `option_zero_fee_commitments`.
+		ret.clear_static_remote_key();
+	} else if config.channel_handshake_config.negotiate_anchors_zero_fee_htlc_tx &&
 		their_features.supports_anchors_zero_fee_htlc_tx() {
 		ret.set_anchors_zero_fee_htlc_tx_required();
 	}
@@ -13104,6 +13140,30 @@ mod tests {
 	fn test_supports_anchors_zero_htlc_tx_fee() {
 		// Tests that if both sides support and negotiate `anchors_zero_fee_htlc_tx`, it is the
 		// resulting `channel_type`.
+		let mut config = UserConfig::default();
+		config.channel_handshake_config.negotiate_anchors_zero_fee_htlc_tx = true;
+
+		let mut expected_channel_type = ChannelTypeFeatures::empty();
+		expected_channel_type.set_static_remote_key_required();
+		expected_channel_type.set_anchors_zero_fee_htlc_tx_required();
+
+		do_test_supports_channel_type(config, expected_channel_type)
+	}
+
+	#[test]
+	fn test_supports_zero_fee_commitments() {
+		// Tests that if both sides support and negotiate `anchors_zero_fee_commitments`, it is
+		// the resulting `channel_type`.
+		let mut config = UserConfig::default();
+		config.channel_handshake_config.negotiate_anchor_zero_fee_commitments = true;
+
+		let mut expected_channel_type = ChannelTypeFeatures::empty();
+		expected_channel_type.set_anchor_zero_fee_commitments_required();
+
+		do_test_supports_channel_type(config, expected_channel_type)
+	}
+
+	fn do_test_supports_channel_type(config: UserConfig, expected_channel_type: ChannelTypeFeatures) {
 		let secp_ctx = Secp256k1::new();
 		let fee_estimator = LowerBoundedFeeEstimator::new(&TestFeeEstimator{fee_est: 15000});
 		let network = Network::Testnet;
@@ -13113,21 +13173,14 @@ mod tests {
 		let node_id_a = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[1; 32]).unwrap());
 		let node_id_b = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[2; 32]).unwrap());
 
-		let mut config = UserConfig::default();
-		config.channel_handshake_config.negotiate_anchors_zero_fee_htlc_tx = true;
-
-		// It is not enough for just the initiator to signal `option_anchors_zero_fee_htlc_tx`, both
-		// need to signal it.
+		// Assert that we don't get the target channel type when the receiving node does not signal
+		// support.
 		let channel_a = OutboundV1Channel::<&TestKeysInterface>::new(
 			&fee_estimator, &&keys_provider, &&keys_provider, node_id_b,
 			&channelmanager::provided_init_features(&UserConfig::default()), 10000000, 100000, 42,
 			&config, 0, 42, None, &logger
 		).unwrap();
-		assert!(!channel_a.funding.get_channel_type().supports_anchors_zero_fee_htlc_tx());
-
-		let mut expected_channel_type = ChannelTypeFeatures::empty();
-		expected_channel_type.set_static_remote_key_required();
-		expected_channel_type.set_anchors_zero_fee_htlc_tx_required();
+		assert!(channel_a.funding.get_channel_type() != &expected_channel_type);
 
 		let mut channel_a = OutboundV1Channel::<&TestKeysInterface>::new(
 			&fee_estimator, &&keys_provider, &&keys_provider, node_id_b,
@@ -13144,6 +13197,14 @@ mod tests {
 
 		assert_eq!(channel_a.funding.get_channel_type(), &expected_channel_type);
 		assert_eq!(channel_b.funding.get_channel_type(), &expected_channel_type);
+
+		if expected_channel_type.supports_anchor_zero_fee_commitments() {
+			assert_eq!(channel_a.context.feerate_per_kw, 0);
+			assert_eq!(channel_b.context.feerate_per_kw, 0);
+		} else {
+			assert_ne!(channel_a.context.feerate_per_kw, 0);
+			assert_ne!(channel_b.context.feerate_per_kw, 0);
+		}
 	}
 
 	#[test]

lightning/src/ln/channel_acceptance_tests.rs

@@ -0,0 +1,189 @@
+//! Various unit tests covering acceptance of incoming channels and negotiation of channel types.
+
+use crate::events::Event;
+use crate::ln::functional_test_utils::*;
+use crate::ln::msgs::{
+	AcceptChannel, BaseMessageHandler, ChannelMessageHandler, ErrorAction, MessageSendEvent,
+};
+use crate::prelude::*;
+use crate::util::config::{ChannelConfigOverrides, ChannelHandshakeConfigUpdate, UserConfig};
+use lightning_types::features::ChannelTypeFeatures;
+
+#[test]
+fn test_inbound_anchors_manual_acceptance() {
+	let mut anchors_cfg = test_default_channel_config();
+	anchors_cfg.channel_handshake_config.negotiate_anchors_zero_fee_htlc_tx = true;
+	do_test_manual_inbound_accept_with_override(anchors_cfg, None);
+}
+
+#[test]
+fn test_inbound_anchors_manual_acceptance_overridden() {
+	let overrides = ChannelConfigOverrides {
+		handshake_overrides: Some(ChannelHandshakeConfigUpdate {
+			max_inbound_htlc_value_in_flight_percent_of_channel: Some(5),
+			htlc_minimum_msat: Some(1000),
+			minimum_depth: Some(2),
+			to_self_delay: Some(200),
+			max_accepted_htlcs: Some(5),
+			channel_reserve_proportional_millionths: Some(20000),
+		}),
+		update_overrides: None,
+	};
+
+	let mut anchors_cfg = test_default_channel_config();
+	anchors_cfg.channel_handshake_config.negotiate_anchors_zero_fee_htlc_tx = true;
+
+	let accept_message = do_test_manual_inbound_accept_with_override(anchors_cfg, Some(overrides));
+	assert_eq!(accept_message.common_fields.max_htlc_value_in_flight_msat, 5_000_000);
+	assert_eq!(accept_message.common_fields.htlc_minimum_msat, 1_000);
+	assert_eq!(accept_message.common_fields.minimum_depth, 2);
+	assert_eq!(accept_message.common_fields.to_self_delay, 200);
+	assert_eq!(accept_message.common_fields.max_accepted_htlcs, 5);
+	assert_eq!(accept_message.channel_reserve_satoshis, 2_000);
+}
+
+#[test]
+fn test_inbound_zero_fee_commitments_acceptance() {
+	let mut zero_fee_cfg = test_default_channel_config();
+	zero_fee_cfg.channel_handshake_config.negotiate_anchor_zero_fee_commitments = true;
+	do_test_manual_inbound_accept_with_override(zero_fee_cfg, None);
+}
+
+fn do_test_manual_inbound_accept_with_override(
+	start_cfg: UserConfig, config_overrides: Option<ChannelConfigOverrides>,
+) -> AcceptChannel {
+	let mut mannual_accept_cfg = start_cfg.clone();
+	mannual_accept_cfg.manually_accept_inbound_channels = true;
+
+	let chanmon_cfgs = create_chanmon_cfgs(3);
+	let node_cfgs = create_node_cfgs(3, &chanmon_cfgs);
+	let node_chanmgrs = create_node_chanmgrs(
+		3,
+		&node_cfgs,
+		&[Some(start_cfg.clone()), Some(start_cfg.clone()), Some(mannual_accept_cfg.clone())],
+	);
+	let nodes = create_network(3, &node_cfgs, &node_chanmgrs);
+
+	nodes[0]
+		.node
+		.create_channel(nodes[1].node.get_our_node_id(), 100_000, 0, 42, None, None)
+		.unwrap();
+	let open_channel_msg = get_event_msg!(
+		nodes[0],
+		MessageSendEvent::SendOpenChannel,
+		nodes[1].node.get_our_node_id()
+	);
+
+	nodes[1].node.handle_open_channel(nodes[0].node.get_our_node_id(), &open_channel_msg);
+	assert!(nodes[1].node.get_and_clear_pending_events().is_empty());
+	let msg_events = nodes[1].node.get_and_clear_pending_msg_events();
+	match &msg_events[0] {
+		MessageSendEvent::HandleError { node_id, action } => {
+			assert_eq!(*node_id, nodes[0].node.get_our_node_id());
+			match action {
+				ErrorAction::SendErrorMessage { msg } => {
+					assert_eq!(msg.data, "No channels with anchor outputs accepted".to_owned())
+				},
+				_ => panic!("Unexpected error action"),
+			}
+		},
+		_ => panic!("Unexpected event"),
+	}
+
+	nodes[2].node.handle_open_channel(nodes[0].node.get_our_node_id(), &open_channel_msg);
+	let events = nodes[2].node.get_and_clear_pending_events();
+	match events[0] {
+		Event::OpenChannelRequest { temporary_channel_id, .. } => nodes[2]
+			.node
+			.accept_inbound_channel(
+				&temporary_channel_id,
+				&nodes[0].node.get_our_node_id(),
+				23,
+				config_overrides,
+			)
+			.unwrap(),
+		_ => panic!("Unexpected event"),
+	}
+	get_event_msg!(nodes[2], MessageSendEvent::SendAcceptChannel, nodes[0].node.get_our_node_id())
+}
+
+#[test]
+fn test_anchors_zero_fee_htlc_tx_downgrade() {
+	// Tests that if both nodes support anchors, but the remote node does not want to accept
+	// anchor channels at the moment, an error it sent to the local node such that it can retry
+	// the channel without the anchors feature.
+	let mut anchors_config = test_default_channel_config();
+	anchors_config.channel_handshake_config.negotiate_anchors_zero_fee_htlc_tx = true;
+	anchors_config.manually_accept_inbound_channels = true;
+
+	do_test_channel_type_downgrade(anchors_config, |features| {
+		features.supports_anchors_zero_fee_htlc_tx()
+	})
+}
+
+#[test]
+fn test_zero_fee_commitments_downgrade() {
+	// Tests that the local node will retry without zero fee commitments in the case where the
+	// remote node supports the feature but does not accept it.
+	let mut zero_fee_config = test_default_channel_config();
+	zero_fee_config.channel_handshake_config.negotiate_anchor_zero_fee_commitments = true;
+	zero_fee_config.channel_handshake_config.negotiate_anchors_zero_fee_htlc_tx = true;
+	zero_fee_config.manually_accept_inbound_channels = true;
+
+	do_test_channel_type_downgrade(zero_fee_config, |features| {
+		features.supports_anchor_zero_fee_commitments()
+	})
+}
+
+fn do_test_channel_type_downgrade<F>(user_cfg: UserConfig, start_type_set: F)
+where
+	F: Fn(&ChannelTypeFeatures) -> bool,
+{
+	let chanmon_cfgs = create_chanmon_cfgs(2);
+	let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
+	let node_chanmgrs =
+		create_node_chanmgrs(2, &node_cfgs, &[Some(user_cfg.clone()), Some(user_cfg.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()
+	);
+	assert!(start_type_set(open_channel_msg.common_fields.channel_type.as_ref().unwrap()));
+
+	nodes[1].node.handle_open_channel(nodes[0].node.get_our_node_id(), &open_channel_msg);
+	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(),
+					error_message.to_string(),
+				)
+				.unwrap();
+		},
+		_ => panic!("Unexpected event"),
+	}
+
+	let error_msg = get_err_msg(&nodes[1], &nodes[0].node.get_our_node_id());
+	nodes[0].node.handle_error(nodes[1].node.get_our_node_id(), &error_msg);
+
+	let open_channel_msg = get_event_msg!(
+		nodes[0],
+		MessageSendEvent::SendOpenChannel,
+		nodes[1].node.get_our_node_id()
+	);
+	assert!(!start_type_set(open_channel_msg.common_fields.channel_type.as_ref().unwrap()));
+
+	// Since nodes[1] should not have accepted the channel, it should
+	// not have generated any events.
+	assert!(nodes[1].node.get_and_clear_pending_events().is_empty());
+}