Add LSPS2ServiceEvent handling

.. so far we just silently fail if something goes wrong, eventually
we'll need to implement retrying channel opens to honor buy requests
that didn't succeed on the first attempt.

Author: tnull

src/builder.rs

@@ -1218,6 +1218,7 @@ fn build_with_store_internal(
 	let (liquidity_source, custom_message_handler) =
 		if let Some(lsc) = liquidity_source_config.as_ref() {
 			let mut liquidity_source_builder = LiquiditySourceBuilder::new(
+				Arc::clone(&wallet),
 				Arc::clone(&channel_manager),
 				Arc::clone(&keys_manager),
 				Arc::clone(&chain_source),

src/liquidity.rs

@@ -11,7 +11,7 @@ use crate::chain::ChainSource;
 use crate::connection::ConnectionManager;
 use crate::logger::{log_debug, log_error, log_info, LdkLogger, Logger};
 use crate::types::{ChannelManager, KeysManager, LiquidityManager, PeerManager, Wallet};
-use crate::{Config, Error};
+use crate::{total_anchor_channels_reserve_sats, Config, Error};
 
 use lightning::events::HTLCDestination;
 use lightning::ln::channelmanager::{InterceptId, MIN_FINAL_CLTV_EXPIRY_DELTA};
@@ -27,8 +27,8 @@ use lightning_liquidity::lsps1::client::LSPS1ClientConfig as LdkLSPS1ClientConfi
 use lightning_liquidity::lsps1::event::LSPS1ClientEvent;
 use lightning_liquidity::lsps1::msgs::{ChannelInfo, LSPS1Options, OrderId, OrderParameters};
 use lightning_liquidity::lsps2::client::LSPS2ClientConfig as LdkLSPS2ClientConfig;
-use lightning_liquidity::lsps2::event::LSPS2ClientEvent;
-use lightning_liquidity::lsps2::msgs::OpeningFeeParams;
+use lightning_liquidity::lsps2::event::{LSPS2ClientEvent, LSPS2ServiceEvent};
+use lightning_liquidity::lsps2::msgs::{OpeningFeeParams, RawOpeningFeeParams};
 use lightning_liquidity::lsps2::service::LSPS2ServiceConfig as LdkLSPS2ServiceConfig;
 use lightning_liquidity::lsps2::utils::compute_opening_fee;
 use lightning_liquidity::{LiquidityClientConfig, LiquidityServiceConfig};
@@ -40,13 +40,21 @@ use bitcoin::secp256k1::{PublicKey, Secp256k1};
 
 use tokio::sync::oneshot;
 
+use chrono::{DateTime, Utc};
+
+use rand::Rng;
+
 use std::collections::HashMap;
 use std::ops::Deref;
 use std::sync::{Arc, Mutex, RwLock};
 use std::time::Duration;
 
 const LIQUIDITY_REQUEST_TIMEOUT_SECS: u64 = 5;
 
+const LSPS2_GETINFO_REQUEST_EXPIRY: Duration = Duration::from_secs(60 * 60 * 24);
+const LSPS2_CLIENT_TRUSTS_LSP_MODE: bool = true;
+const LSPS2_CHANNEL_CLTV_EXPIRY_DELTA: u32 = 72;
+
 struct LSPS1Client {
 	lsp_node_id: PublicKey,
 	lsp_address: SocketAddress,
@@ -132,6 +140,7 @@ where
 	lsps1_client: Option<LSPS1Client>,
 	lsps2_client: Option<LSPS2Client>,
 	lsps2_service: Option<LSPS2Service>,
+	wallet: Arc<Wallet>,
 	channel_manager: Arc<ChannelManager>,
 	keys_manager: Arc<KeysManager>,
 	chain_source: Arc<ChainSource>,
@@ -144,7 +153,7 @@ where
 	L::Target: LdkLogger,
 {
 	pub(crate) fn new(
-		channel_manager: Arc<ChannelManager>, keys_manager: Arc<KeysManager>,
+		wallet: Arc<Wallet>, channel_manager: Arc<ChannelManager>, keys_manager: Arc<KeysManager>,
 		chain_source: Arc<ChainSource>, config: Arc<Config>, logger: L,
 	) -> Self {
 		let lsps1_client = None;
@@ -154,6 +163,7 @@ where
 			lsps1_client,
 			lsps2_client,
 			lsps2_service,
+			wallet,
 			channel_manager,
 			keys_manager,
 			chain_source,
@@ -232,7 +242,9 @@ where
 			lsps1_client: self.lsps1_client,
 			lsps2_client: self.lsps2_client,
 			lsps2_service: self.lsps2_service,
+			wallet: self.wallet,
 			channel_manager: self.channel_manager,
+			peer_manager: RwLock::new(None),
 			keys_manager: self.keys_manager,
 			liquidity_manager,
 			config: self.config,
@@ -248,7 +260,9 @@ where
 	lsps1_client: Option<LSPS1Client>,
 	lsps2_client: Option<LSPS2Client>,
 	lsps2_service: Option<LSPS2Service>,
+	wallet: Arc<Wallet>,
 	channel_manager: Arc<ChannelManager>,
+	peer_manager: RwLock<Option<Arc<PeerManager>>>,
 	keys_manager: Arc<KeysManager>,
 	liquidity_manager: Arc<LiquidityManager>,
 	config: Arc<Config>,
@@ -260,6 +274,7 @@ where
 	L::Target: LdkLogger,
 {
 	pub(crate) fn set_peer_manager(&self, peer_manager: Arc<PeerManager>) {
+		*self.peer_manager.write().unwrap() = Some(Arc::clone(&peer_manager));
 		let process_msgs_callback = move || peer_manager.process_events();
 		self.liquidity_manager.set_process_msgs_callback(process_msgs_callback);
 	}
@@ -447,6 +462,254 @@ where
 					log_error!(self.logger, "Received unexpected LSPS1Client::OrderStatus event!");
 				}
 			},
+			Event::LSPS2Service(LSPS2ServiceEvent::GetInfo {
+				request_id,
+				counterparty_node_id,
+				token,
+			}) => {
+				if let Some(lsps2_service_handler) =
+					self.liquidity_manager.lsps2_service_handler().as_ref()
+				{
+					let service_config = if let Some(service_config) =
+						self.lsps2_service.as_ref().map(|s| s.service_config.clone())
+					{
+						service_config
+					} else {
+						log_error!(self.logger, "Failed to handle LSPS2ServiceEvent as LSPS2 liquidity service was not configured.",);
+						return;
+					};
+
+					if let Some(required) = service_config.require_token {
+						if token != Some(required) {
+							log_error!(
+								self.logger,
+								"Rejecting LSPS2 request {:?} from counterparty {} as the client provided an invalid token.", 
+								request_id,
+								counterparty_node_id
+							);
+							lsps2_service_handler.invalid_token_provided(&counterparty_node_id, request_id.clone()).unwrap_or_else(|e| {
+								debug_assert!(false, "Failed to reject LSPS2 request. This should never happen.");
+								log_error!(
+									self.logger,
+									"Failed to reject LSPS2 request {:?} from counterparty {} due to: {:?}. This should never happen.",
+									request_id,
+									counterparty_node_id,
+									e
+								);
+							});
+							return;
+						}
+					}
+
+					let mut valid_until: DateTime<Utc> = Utc::now();
+					valid_until += LSPS2_GETINFO_REQUEST_EXPIRY;
+
+					let opening_fee_params = RawOpeningFeeParams {
+						min_fee_msat: service_config.min_channel_opening_fee_msat,
+						proportional: service_config.channel_opening_fee_ppm,
+						valid_until,
+						min_lifetime: service_config.min_channel_lifetime,
+						max_client_to_self_delay: service_config.max_client_to_self_delay,
+						min_payment_size_msat: service_config.min_payment_size_msat,
+						max_payment_size_msat: service_config.max_payment_size_msat,
+					};
+
+					let opening_fee_params_menu = vec![opening_fee_params];
+
+					if let Err(e) = lsps2_service_handler.opening_fee_params_generated(
+						&counterparty_node_id,
+						request_id,
+						opening_fee_params_menu,
+					) {
+						log_error!(
+							self.logger,
+							"Failed to handle generated opening fee params: {:?}",
+							e
+						);
+					}
+				} else {
+					log_error!(self.logger, "Failed to handle LSPS2ServiceEvent as LSPS2 liquidity service was not configured.",);
+					return;
+				}
+			},
+			Event::LSPS2Service(LSPS2ServiceEvent::BuyRequest {
+				request_id,
+				counterparty_node_id,
+				opening_fee_params: _,
+				payment_size_msat,
+			}) => {
+				if let Some(lsps2_service_handler) =
+					self.liquidity_manager.lsps2_service_handler().as_ref()
+				{
+					let service_config = if let Some(service_config) =
+						self.lsps2_service.as_ref().map(|s| s.service_config.clone())
+					{
+						service_config
+					} else {
+						log_error!(self.logger, "Failed to handle LSPS2ServiceEvent as LSPS2 liquidity service was not configured.",);
+						return;
+					};
+
+					let user_channel_id: u128 = rand::thread_rng().gen::<u128>();
+					let intercept_scid = self.channel_manager.get_intercept_scid();
+
+					if let Some(payment_size_msat) = payment_size_msat {
+						// We already check this in `lightning-liquidity`, but better safe than
+						// sorry.
+						//
+						// TODO: We might want to eventually send back an error here, but we
+						// currently can't and have to trust `lightning-liquidity` is doing the
+						// right thing.
+						//
+						// TODO: Eventually we also might want to make sure that we have sufficient
+						// liquidity for the channel opening here.
+						if payment_size_msat > service_config.max_payment_size_msat
+							|| payment_size_msat < service_config.min_payment_size_msat
+						{
+							log_error!(
+								self.logger,
+								"Rejecting to handle LSPS2 buy request {:?} from counterparty {} as the client requested an invalid payment size.",
+								request_id,
+								counterparty_node_id
+							);
+							return;
+						}
+					}
+
+					match lsps2_service_handler.invoice_parameters_generated(
+						&counterparty_node_id,
+						request_id,
+						intercept_scid,
+						LSPS2_CHANNEL_CLTV_EXPIRY_DELTA,
+						LSPS2_CLIENT_TRUSTS_LSP_MODE,
+						user_channel_id,
+					) {
+						Ok(()) => {},
+						Err(e) => {
+							log_error!(
+								self.logger,
+								"Failed to provide invoice parameters: {:?}",
+								e
+							);
+							return;
+						},
+					}
+				} else {
+					log_error!(self.logger, "Failed to handle LSPS2ServiceEvent as LSPS2 liquidity service was not configured.",);
+					return;
+				}
+			},
+			Event::LSPS2Service(LSPS2ServiceEvent::OpenChannel {
+				their_network_key,
+				amt_to_forward_msat,
+				opening_fee_msat: _,
+				user_channel_id,
+				intercept_scid: _,
+			}) => {
+				if self.liquidity_manager.lsps2_service_handler().is_none() {
+					log_error!(self.logger, "Failed to handle LSPS2ServiceEvent as LSPS2 liquidity service was not configured.",);
+					return;
+				};
+
+				let service_config = if let Some(service_config) =
+					self.lsps2_service.as_ref().map(|s| s.service_config.clone())
+				{
+					service_config
+				} else {
+					log_error!(self.logger, "Failed to handle LSPS2ServiceEvent as LSPS2 liquidity service was not configured.",);
+					return;
+				};
+
+				let init_features = if let Some(peer_manager) =
+					self.peer_manager.read().unwrap().as_ref()
+				{
+					// Fail if we're not connected to the prospective channel partner.
+					if let Some(peer) = peer_manager.peer_by_node_id(&their_network_key) {
+						peer.init_features
+					} else {
+						// TODO: We just silently fail here. Eventually we will need to remember
+						// the pending requests and regularly retry opening the channel until we
+						// succeed.
+						log_error!(
+							self.logger,
+							"Failed to open LSPS2 channel to {} due to peer not being not connected.",
+							their_network_key,
+						);
+						return;
+					}
+				} else {
+					debug_assert!(false, "Failed to handle LSPS2ServiceEvent as peer manager isn't available. This should never happen.",);
+					log_error!(self.logger, "Failed to handle LSPS2ServiceEvent as peer manager isn't available. This should never happen.",);
+					return;
+				};
+
+				// Fail if we have insufficient onchain funds available.
+				let over_provisioning_msat = (amt_to_forward_msat
+					* service_config.channel_over_provisioning_ppm as u64)
+					/ 1_000_000;
+				let channel_amount_sats = (amt_to_forward_msat + over_provisioning_msat) / 1000;
+				let cur_anchor_reserve_sats =
+					total_anchor_channels_reserve_sats(&self.channel_manager, &self.config);
+				let spendable_amount_sats =
+					self.wallet.get_spendable_amount_sats(cur_anchor_reserve_sats).unwrap_or(0);
+				let required_funds_sats = channel_amount_sats
+					+ self.config.anchor_channels_config.as_ref().map_or(0, |c| {
+						if init_features.requires_anchors_zero_fee_htlc_tx()
+							&& !c.trusted_peers_no_reserve.contains(&their_network_key)
+						{
+							c.per_channel_reserve_sats
+						} else {
+							0
+						}
+					});
+				if spendable_amount_sats < required_funds_sats {
+					log_error!(self.logger,
+						"Unable to create channel due to insufficient funds. Available: {}sats, Required: {}sats",
+						spendable_amount_sats, channel_amount_sats
+					);
+					// TODO: We just silently fail here. Eventually we will need to remember
+					// the pending requests and regularly retry opening the channel until we
+					// succeed.
+					return;
+				}
+
+				let mut config = *self.channel_manager.get_current_default_configuration();
+
+				// Set the HTLC-value-in-flight to 100% of the channel value to ensure we can
+				// forward the payment.
+				config
+					.channel_handshake_config
+					.max_inbound_htlc_value_in_flight_percent_of_channel = 100;
+
+				// We set the forwarding fee to 0 for now as we're getting paid by the channel fee.
+				//
+				// TODO: revisit this decision eventually.
+				config.channel_config.forwarding_fee_base_msat = 0;
+				config.channel_config.forwarding_fee_proportional_millionths = 0;
+
+				match self.channel_manager.create_channel(
+					their_network_key,
+					channel_amount_sats,
+					0,
+					user_channel_id,
+					None,
+					Some(config),
+				) {
+					Ok(_) => {},
+					Err(e) => {
+						// TODO: We just silently fail here. Eventually we will need to remember
+						// the pending requests and regularly retry opening the channel until we
+						// succeed.
+						log_error!(
+							self.logger,
+							"Failed to open LSPS2 channel to {}: {:?}",
+							their_network_key,
+							e
+						);
+						return;
+					},
+				}
+			},
 			Event::LSPS2Client(LSPS2ClientEvent::OpeningParametersReady {
 				request_id,
 				counterparty_node_id,