channelmanager: add multi-node receive support

Now if we receive an onion that we're intended to
forward to one of our fake hops, we'll use its secret
to unwrap the onion a second time and receive the payment

Author: valentinewallace

lightning-invoice/src/utils.rs

@@ -5,20 +5,99 @@ use payment::{Payer, Router};
 
 use bech32::ToBase32;
 use bitcoin_hashes::Hash;
+use bitcoin_hashes::sha256::Hash as Sha256;
 use lightning::chain;
 use lightning::chain::chaininterface::{BroadcasterInterface, FeeEstimator};
 use lightning::chain::keysinterface::{Sign, KeysInterface};
 use lightning::ln::{PaymentHash, PaymentPreimage, PaymentSecret};
-use lightning::ln::channelmanager::{ChannelDetails, ChannelManager, PaymentId, PaymentSendFailure, MIN_FINAL_CLTV_EXPIRY};
+use lightning::ln::channelmanager::{ChannelDetails, ChannelManager, PaymentId, PaymentSendFailure, MIN_FINAL_CLTV_EXPIRY, MIN_CLTV_EXPIRY_DELTA};
 use lightning::ln::msgs::LightningError;
 use lightning::routing::scoring::Score;
 use lightning::routing::network_graph::{NetworkGraph, RoutingFees};
 use lightning::routing::router::{Route, RouteHint, RouteHintHop, RouteParameters, find_route};
 use lightning::util::logger::Logger;
+use secp256k1;
+use secp256k1::{Secp256k1, SecretKey};
 use secp256k1::key::PublicKey;
 use std::convert::TryInto;
 use std::ops::Deref;
 
+/// TODO docs after interface is settled
+/// TODO instead of passing in the secret, pass in an InvoiceSigner trait object that ChannelManager
+/// implements, maybe?
+pub fn create_multi_receive_invoice(amt_msat: Option<u64>, description: String, payment_hash: PaymentHash, payment_secret: PaymentSecret, channels: &[(u64, PublicKey, &ChannelDetails)], fake_node_secret: SecretKey, network: Currency) ->
+	Result<Invoice, SignOrCreationError<()>>
+{
+	let fake_node_pubkey = PublicKey::from_secret_key(&Secp256k1::new(), &fake_node_secret);
+	let mut route_hints = vec![];
+	for (fake_scid, real_node_pubkey, channel) in channels {
+		let short_channel_id = match channel.short_channel_id {
+			Some(id) => id,
+			None => continue,
+		};
+		let forwarding_info = match &channel.counterparty.forwarding_info {
+			Some(info) => info.clone(),
+			None => continue,
+		};
+		route_hints.push(RouteHint(vec![
+				RouteHintHop {
+					src_node_id: channel.counterparty.node_id,
+					short_channel_id,
+					fees: RoutingFees {
+						base_msat: forwarding_info.fee_base_msat,
+						proportional_millionths: forwarding_info.fee_proportional_millionths,
+					},
+					cltv_expiry_delta: forwarding_info.cltv_expiry_delta,
+					htlc_minimum_msat: None,
+					htlc_maximum_msat: None,
+				},
+				RouteHintHop {
+					src_node_id: *real_node_pubkey,
+					short_channel_id: *fake_scid,
+					fees: RoutingFees {
+						base_msat: 0,
+						proportional_millionths: 0,
+					},
+					cltv_expiry_delta: MIN_CLTV_EXPIRY_DELTA,
+					htlc_minimum_msat: None,
+					htlc_maximum_msat: None,
+				}
+			])
+		);
+	}
+	// TODO handle empty route hints
+	// TODO comment why mpp isn't enabled
+	let mut invoice = InvoiceBuilder::new(network)
+		.description(description)
+		.current_timestamp()
+		.payee_pub_key(fake_node_pubkey)
+		.payment_hash(Hash::from_slice(&payment_hash.0).unwrap())
+		.payment_secret(payment_secret)
+		.min_final_cltv_expiry(MIN_FINAL_CLTV_EXPIRY.into());
+	if let Some(amt) = amt_msat {
+		invoice = invoice.amount_milli_satoshis(amt);
+	}
+	for hint in route_hints {
+		invoice = invoice.private_route(hint);
+	}
+
+	let raw_invoice = match invoice.build_raw() {
+		Ok(inv) => inv,
+		Err(e) => return Err(SignOrCreationError::CreationError(e))
+	};
+	let hrp_str = raw_invoice.hrp.to_string();
+	let hrp_bytes = hrp_str.as_bytes();
+	let data_without_signature = raw_invoice.data.to_base32();
+	let invoice_preimage = RawInvoice::construct_invoice_preimage(hrp_bytes, &data_without_signature);
+	let secp_ctx = Secp256k1::new();
+	let invoice_preimage_msg = secp256k1::Message::from_slice(&Sha256::hash(&invoice_preimage)).unwrap();
+	let signed_raw_invoice = raw_invoice.sign(|_| Ok(secp_ctx.sign_recoverable(&invoice_preimage_msg, &fake_node_secret)));
+	match signed_raw_invoice {
+		Ok(inv) => Ok(Invoice::from_signed(inv).unwrap()),
+		Err(e) => Err(SignOrCreationError::SignError(e))
+	}
+}
+
 /// Utility to construct an invoice. Generally, unless you want to do something like a custom
 /// cltv_expiry, this is what you should be using to create an invoice. The reason being, this
 /// method stores the invoice's payment secret and preimage in `ChannelManager`, so (a) the user
@@ -155,16 +234,22 @@ where
 }
 
 #[cfg(test)]
-mod test {
+mod tests {
 	use {Currency, Description, InvoiceDescription};
-	use lightning::ln::PaymentHash;
-	use lightning::ln::channelmanager::MIN_FINAL_CLTV_EXPIRY;
+	use lightning::{expect_payment_sent, get_revoke_commit_msgs};
+	use lightning::chain::keysinterface::KeyMaterial;
+	use lightning::ln::{PaymentPreimage, PaymentHash};
+	use lightning::ln::channelmanager::{ChannelDetails, MIN_FINAL_CLTV_EXPIRY};
 	use lightning::ln::functional_test_utils::*;
 	use lightning::ln::features::InitFeatures;
 	use lightning::ln::msgs::ChannelMessageHandler;
 	use lightning::routing::router::{Payee, RouteParameters, find_route};
-	use lightning::util::events::MessageSendEventsProvider;
+	use lightning::util::events::{Event, MessageSendEvent, MessageSendEventsProvider, PaymentPurpose};
 	use lightning::util::test_utils;
+	use bitcoin_hashes::sha256::Hash as Sha256;
+	use bitcoin_hashes::Hash;
+	use secp256k1::PublicKey;
+
 	#[test]
 	fn test_from_channelmanager() {
 		let chanmon_cfgs = create_chanmon_cfgs(2);
@@ -215,4 +300,128 @@ mod test {
 		let events = nodes[1].node.get_and_clear_pending_msg_events();
 		assert_eq!(events.len(), 2);
 	}
+
+	#[test]
+	fn test_multi_node_receive() {
+		do_test_multi_node_receive(true);
+		do_test_multi_node_receive(false);
+	}
+
+	fn do_test_multi_node_receive(user_generated_pmt_hash: bool) {
+		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, &[None, None, None]);
+		let nodes = create_network(3, &node_cfgs, &node_chanmgrs);
+		let chan_0_1 = create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 100000, 10001, InitFeatures::known(), InitFeatures::known());
+		nodes[0].node.handle_channel_update(&nodes[1].node.get_our_node_id(), &chan_0_1.1);
+		nodes[1].node.handle_channel_update(&nodes[0].node.get_our_node_id(), &chan_0_1.0);
+		let chan_0_2 = create_announced_chan_between_nodes_with_value(&nodes, 0, 2, 100000, 10001, InitFeatures::known(), InitFeatures::known());
+		nodes[0].node.handle_channel_update(&nodes[2].node.get_our_node_id(), &chan_0_2.1);
+		nodes[2].node.handle_channel_update(&nodes[0].node.get_our_node_id(), &chan_0_2.0);
+		let phantom_key_material = KeyMaterial([42; 32]);
+		let phantom_scid = 42;
+		let phantom_secret = nodes[1].node.create_fake_last_hop(phantom_key_material, phantom_scid);
+		nodes[2].node.create_fake_last_hop(phantom_key_material, phantom_scid);
+
+		let (mut payment_preimage_opt, payment_hash, payment_secret) = {
+			if user_generated_pmt_hash {
+				let payment_preimage = PaymentPreimage([1; 32]);
+				let payment_hash = PaymentHash(Sha256::hash(&payment_preimage.0[..]).into_inner());
+				let payment_secret = nodes[1].node.create_inbound_payment_for_hash_fake_last_hop(payment_hash, Some(10_000), 3600, phantom_scid).unwrap();
+				(Some(payment_preimage), payment_hash, payment_secret)
+			} else {
+				let (payment_hash, payment_secret) = nodes[1].node.create_inbound_payment_for_fake_last_hop(Some(10_000), 3600, phantom_scid).unwrap();
+				(None, payment_hash, payment_secret)
+			}
+		};
+		let channels_1 = nodes[1].node.list_channels();
+		let channels_2 = nodes[2].node.list_channels();
+		let mut route_hints = channels_1.iter().map(|e| (phantom_scid, nodes[1].node.get_our_node_id(), e)).collect::<Vec<(u64, PublicKey, &ChannelDetails)>>();
+		for channel in channels_2.iter() {
+			route_hints.push((phantom_scid, nodes[2].node.get_our_node_id(), &channel));
+		}
+		let invoice = ::utils::create_multi_receive_invoice(Some(10_000), "test".to_string(), payment_hash, payment_secret, &route_hints, phantom_secret, Currency::BitcoinTestnet).unwrap();
+
+		assert_eq!(invoice.min_final_cltv_expiry(), MIN_FINAL_CLTV_EXPIRY as u64);
+		assert_eq!(invoice.description(), InvoiceDescription::Direct(&Description("test".to_string())));
+		assert_eq!(invoice.route_hints().len(), 2);
+		// assert!(!invoice.features().unwrap().supports_basic_mpp()); todo get this work?
+
+		let payee = Payee::from_node_id(invoice.recover_payee_pub_key())
+			.with_features(invoice.features().unwrap().clone())
+			.with_route_hints(invoice.route_hints());
+		let params = RouteParameters {
+			payee,
+			final_value_msat: invoice.amount_milli_satoshis().unwrap(),
+			final_cltv_expiry_delta: invoice.min_final_cltv_expiry() as u32,
+		};
+		let first_hops = nodes[0].node.list_usable_channels();
+		let network_graph = node_cfgs[0].network_graph;
+		let logger = test_utils::TestLogger::new();
+		let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+		let route = find_route(
+			&nodes[0].node.get_our_node_id(), &params, network_graph,
+			Some(&first_hops.iter().collect::<Vec<_>>()), &logger, &scorer,
+		).unwrap();
+		let payment_event = {
+			let mut payment_hash = PaymentHash([0; 32]);
+			payment_hash.0.copy_from_slice(&invoice.payment_hash().as_ref()[0..32]);
+			nodes[0].node.send_payment(&route, payment_hash, &Some(invoice.payment_secret().clone())).unwrap();
+			let mut added_monitors = nodes[0].chain_monitor.added_monitors.lock().unwrap();
+			assert_eq!(added_monitors.len(), 1);
+			added_monitors.clear();
+
+			let mut events = nodes[0].node.get_and_clear_pending_msg_events();
+			assert_eq!(events.len(), 1);
+			SendEvent::from_event(events.remove(0))
+		};
+		nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &payment_event.msgs[0]);
+		nodes[1].node.handle_commitment_signed(&nodes[0].node.get_our_node_id(), &payment_event.commitment_msg);
+		check_added_monitors!(nodes[1], 1);
+		let (raa_1, cs_1) = get_revoke_commit_msgs!(nodes[1], nodes[0].node.get_our_node_id());
+		check_added_monitors!(nodes[1], 0);
+		assert!(nodes[1].node.get_and_clear_pending_msg_events().is_empty());
+		nodes[0].node.handle_revoke_and_ack(&nodes[1].node.get_our_node_id(), &raa_1);
+		assert!(nodes[0].node.get_and_clear_pending_msg_events().is_empty());
+		check_added_monitors!(nodes[0], 1);
+		nodes[0].node.handle_commitment_signed(&nodes[1].node.get_our_node_id(), &cs_1);
+		let raa_0 = {
+			let events = nodes[0].node.get_and_clear_pending_msg_events();
+			assert_eq!(events.len(), 1);
+			match events[0] {
+				MessageSendEvent::SendRevokeAndACK { ref node_id, ref msg } => {
+					assert_eq!(*node_id, nodes[1].node.get_our_node_id());
+					(*msg).clone()
+				},
+				_ => panic!("Unexpected event"),
+			}
+		};
+		check_added_monitors!(nodes[0], 1);
+		nodes[1].node.handle_revoke_and_ack(&nodes[0].node.get_our_node_id(), &raa_0);
+
+		let events = nodes[1].node.get_and_clear_pending_events();
+		assert_eq!(events.len(), 1);
+		match events[0] {
+			Event::PendingHTLCsForwardable { .. } => { },
+			_ => panic!("Unexpected event"),
+		};
+		nodes[1].node.process_pending_htlc_forwards();
+		let events = nodes[1].node.get_and_clear_pending_events();
+		assert_eq!(events.len(), 1);
+		match events[0] {
+			Event::PaymentReceived {
+				purpose: PaymentPurpose::InvoicePayment { payment_preimage, payment_secret: secret }, ..
+			} => {
+				assert_eq!(payment_secret, secret);
+				if let Some(preimage) = payment_preimage {
+					payment_preimage_opt = Some(preimage);
+				}
+			},
+			_ => panic!("Unexpected event"),
+		}
+		check_added_monitors!(nodes[1], 1);
+
+		do_claim_payment_along_route(&nodes[0], &vec!(&vec!(&nodes[1])[..]), false, payment_preimage_opt.unwrap());
+		expect_payment_sent!(nodes[0], payment_preimage_opt.unwrap(), Some(0));
+	}
 }