Move general channel behaviour into new ChannelInterface trait

In preparation for the introduction of `InboundV1Channel` and
`OutboundV1Channel`, we move common channel behaviour and helpers to a
new `ChannelInterface` trait.

`Channel` and the upcoming prefunded channel types implement `ChannelInterface`
and only need to provide a way to access their inner `ChannelContext`,
mutably, and immutably, so that these can be called by default methods of
the trait. Further work will pull items which are unique to certain channel
types out of `ChannelContext` and into that channel struct as a field.

Author: dunxen

lightning/src/ln/channel.rs

@@ -40,7 +40,7 @@ use crate::events::{Event, EventHandler, EventsProvider, MessageSendEvent, Messa
 // Since this struct is returned in `list_channels` methods, expose it here in case users want to
 // construct one themselves.
 use crate::ln::{inbound_payment, PaymentHash, PaymentPreimage, PaymentSecret};
-use crate::ln::channel::{Channel, ChannelError, ChannelUpdateStatus, UpdateFulfillCommitFetch};
+use crate::ln::channel::{Channel, ChannelInterface, ChannelError, ChannelUpdateStatus, UpdateFulfillCommitFetch};
 use crate::ln::features::{ChannelFeatures, ChannelTypeFeatures, InitFeatures, NodeFeatures};
 #[cfg(any(feature = "_test_utils", test))]
 use crate::ln::features::InvoiceFeatures;
@@ -1358,56 +1358,6 @@ impl ChannelDetails {
 	pub fn get_outbound_payment_scid(&self) -> Option<u64> {
 		self.short_channel_id.or(self.outbound_scid_alias)
 	}
-
-	fn from_channel<Signer: WriteableEcdsaChannelSigner>(channel: &Channel<Signer>,
-		best_block_height: u32, latest_features: InitFeatures) -> Self {
-
-		let balance = channel.get_available_balances();
-		let (to_remote_reserve_satoshis, to_self_reserve_satoshis) =
-			channel.get_holder_counterparty_selected_channel_reserve_satoshis();
-		ChannelDetails {
-			channel_id: channel.channel_id(),
-			counterparty: ChannelCounterparty {
-				node_id: channel.get_counterparty_node_id(),
-				features: latest_features,
-				unspendable_punishment_reserve: to_remote_reserve_satoshis,
-				forwarding_info: channel.counterparty_forwarding_info(),
-				// Ensures that we have actually received the `htlc_minimum_msat` value
-				// from the counterparty through the `OpenChannel` or `AcceptChannel`
-				// message (as they are always the first message from the counterparty).
-				// Else `Channel::get_counterparty_htlc_minimum_msat` could return the
-				// default `0` value set by `Channel::new_outbound`.
-				outbound_htlc_minimum_msat: if channel.have_received_message() {
-					Some(channel.get_counterparty_htlc_minimum_msat()) } else { None },
-				outbound_htlc_maximum_msat: channel.get_counterparty_htlc_maximum_msat(),
-			},
-			funding_txo: channel.get_funding_txo(),
-			// Note that accept_channel (or open_channel) is always the first message, so
-			// `have_received_message` indicates that type negotiation has completed.
-			channel_type: if channel.have_received_message() { Some(channel.get_channel_type().clone()) } else { None },
-			short_channel_id: channel.get_short_channel_id(),
-			outbound_scid_alias: if channel.is_usable() { Some(channel.outbound_scid_alias()) } else { None },
-			inbound_scid_alias: channel.latest_inbound_scid_alias(),
-			channel_value_satoshis: channel.get_value_satoshis(),
-			feerate_sat_per_1000_weight: Some(channel.get_feerate_sat_per_1000_weight()),
-			unspendable_punishment_reserve: to_self_reserve_satoshis,
-			balance_msat: balance.balance_msat,
-			inbound_capacity_msat: balance.inbound_capacity_msat,
-			outbound_capacity_msat: balance.outbound_capacity_msat,
-			next_outbound_htlc_limit_msat: balance.next_outbound_htlc_limit_msat,
-			user_channel_id: channel.get_user_id(),
-			confirmations_required: channel.minimum_depth(),
-			confirmations: Some(channel.get_funding_tx_confirmations(best_block_height)),
-			force_close_spend_delay: channel.get_counterparty_selected_contest_delay(),
-			is_outbound: channel.is_outbound(),
-			is_channel_ready: channel.is_usable(),
-			is_usable: channel.is_live(),
-			is_public: channel.should_announce(),
-			inbound_htlc_minimum_msat: Some(channel.get_holder_htlc_minimum_msat()),
-			inbound_htlc_maximum_msat: channel.get_holder_htlc_maximum_msat(),
-			config: Some(channel.config()),
-		}
-	}
 }
 
 /// Used by [`ChannelManager::list_recent_payments`] to express the status of recent payments.
@@ -1974,8 +1924,7 @@ where
 				let mut peer_state_lock = peer_state_mutex.lock().unwrap();
 				let peer_state = &mut *peer_state_lock;
 				for (_channel_id, channel) in peer_state.channel_by_id.iter().filter(f) {
-					let details = ChannelDetails::from_channel(channel, best_block_height,
-						peer_state.latest_features.clone());
+					let details = channel.get_channel_details(best_block_height, peer_state.latest_features.clone());
 					res.push(details);
 				}
 			}
@@ -2014,7 +1963,7 @@ where
 			return peer_state.channel_by_id
 				.iter()
 				.map(|(_, channel)|
-					ChannelDetails::from_channel(channel, best_block_height, features.clone()))
+					channel.get_channel_details(best_block_height, features.clone()))
 				.collect();
 		}
 		vec![]

lightning/src/ln/channelmanager.rs

@@ -16,6 +16,7 @@ use crate::chain::channelmonitor::ChannelMonitor;
 use crate::chain::transaction::OutPoint;
 use crate::events::{ClosureReason, Event, HTLCDestination, MessageSendEvent, MessageSendEventsProvider, PathFailure, PaymentPurpose, PaymentFailureReason};
 use crate::ln::{PaymentPreimage, PaymentHash, PaymentSecret};
+use crate::ln::channel::ChannelInterface;
 use crate::ln::channelmanager::{AChannelManager, ChainParameters, ChannelManager, ChannelManagerReadArgs, RAACommitmentOrder, PaymentSendFailure, RecipientOnionFields, PaymentId, MIN_CLTV_EXPIRY_DELTA};
 use crate::routing::gossip::{P2PGossipSync, NetworkGraph, NetworkUpdate};
 use crate::routing::router::{self, PaymentParameters, Route};

lightning/src/ln/functional_test_utils.rs

@@ -20,7 +20,7 @@ use crate::chain::transaction::OutPoint;
 use crate::sign::{ChannelSigner, EcdsaChannelSigner, EntropySource};
 use crate::events::{Event, MessageSendEvent, MessageSendEventsProvider, PathFailure, PaymentPurpose, ClosureReason, HTLCDestination, PaymentFailureReason};
 use crate::ln::{PaymentPreimage, PaymentSecret, PaymentHash};
-use crate::ln::channel::{commitment_tx_base_weight, COMMITMENT_TX_WEIGHT_PER_HTLC, CONCURRENT_INBOUND_HTLC_FEE_BUFFER, FEE_SPIKE_BUFFER_FEE_INCREASE_MULTIPLE, MIN_AFFORDABLE_HTLC_COUNT};
+use crate::ln::channel::{ChannelInterface, commitment_tx_base_weight, COMMITMENT_TX_WEIGHT_PER_HTLC, CONCURRENT_INBOUND_HTLC_FEE_BUFFER, FEE_SPIKE_BUFFER_FEE_INCREASE_MULTIPLE, MIN_AFFORDABLE_HTLC_COUNT};
 use crate::ln::channelmanager::{self, PaymentId, RAACommitmentOrder, PaymentSendFailure, RecipientOnionFields, BREAKDOWN_TIMEOUT, ENABLE_GOSSIP_TICKS, DISABLE_GOSSIP_TICKS, MIN_CLTV_EXPIRY_DELTA};
 use crate::ln::channel::{Channel, ChannelError};
 use crate::ln::{chan_utils, onion_utils};

lightning/src/ln/functional_tests.rs

@@ -19,7 +19,7 @@ use crate::chain::chaininterface::LowerBoundedFeeEstimator;
 #[cfg(anchors)]
 use crate::events::bump_transaction::BumpTransactionEvent;
 use crate::events::{Event, MessageSendEvent, MessageSendEventsProvider, ClosureReason, HTLCDestination};
-use crate::ln::channel;
+use crate::ln::channel::{self, ChannelInterface};
 #[cfg(anchors)]
 use crate::ln::chan_utils;
 #[cfg(anchors)]

lightning/src/ln/monitor_tests.rs

@@ -15,7 +15,7 @@ use crate::chain::channelmonitor::{CLTV_CLAIM_BUFFER, LATENCY_GRACE_PERIOD_BLOCK
 use crate::sign::{EntropySource, NodeSigner, Recipient};
 use crate::events::{Event, HTLCDestination, MessageSendEvent, MessageSendEventsProvider, PathFailure, PaymentFailureReason};
 use crate::ln::{PaymentHash, PaymentSecret};
-use crate::ln::channel::EXPIRE_PREV_CONFIG_TICKS;
+use crate::ln::channel::{ChannelInterface, EXPIRE_PREV_CONFIG_TICKS};
 use crate::ln::channelmanager::{HTLCForwardInfo, FailureCode, CLTV_FAR_FAR_AWAY, DISABLE_GOSSIP_TICKS, MIN_CLTV_EXPIRY_DELTA, PendingAddHTLCInfo, PendingHTLCInfo, PendingHTLCRouting, PaymentId, RecipientOnionFields};
 use crate::ln::onion_utils;
 use crate::routing::gossip::{NetworkUpdate, RoutingFees};

lightning/src/ln/onion_route_tests.rs

@@ -16,7 +16,7 @@ use crate::chain::channelmonitor::{ANTI_REORG_DELAY, HTLC_FAIL_BACK_BUFFER, LATE
 use crate::sign::EntropySource;
 use crate::chain::transaction::OutPoint;
 use crate::events::{ClosureReason, Event, HTLCDestination, MessageSendEvent, MessageSendEventsProvider, PathFailure, PaymentFailureReason};
-use crate::ln::channel::EXPIRE_PREV_CONFIG_TICKS;
+use crate::ln::channel::{ChannelInterface, EXPIRE_PREV_CONFIG_TICKS};
 use crate::ln::channelmanager::{BREAKDOWN_TIMEOUT, ChannelManager, MPP_TIMEOUT_TICKS, MIN_CLTV_EXPIRY_DELTA, PaymentId, PaymentSendFailure, IDEMPOTENCY_TIMEOUT_TICKS, RecentPaymentDetails, RecipientOnionFields};
 use crate::ln::features::InvoiceFeatures;
 use crate::ln::msgs;