Add message structs required for dual-funded channels
[rust-lightning] / lightning / src / ln / payment_tests.rs
index 15361b98ad71fd9ee1193891aa71f4d45ef5d9a3..0cdc2c9153f634953b83b217067002ecc711e306 100644 (file)
 //! payments thereafter.
 
 use crate::chain::{ChannelMonitorUpdateStatus, Confirm, Listen, Watch};
-use crate::chain::channelmonitor::{ANTI_REORG_DELAY, LATENCY_GRACE_PERIOD_BLOCKS};
-use crate::chain::keysinterface::EntropySource;
+use crate::chain::channelmonitor::{ANTI_REORG_DELAY, HTLC_FAIL_BACK_BUFFER, LATENCY_GRACE_PERIOD_BLOCKS};
+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::channelmanager::{BREAKDOWN_TIMEOUT, ChannelManager, MPP_TIMEOUT_TICKS, MIN_CLTV_EXPIRY_DELTA, PaymentId, PaymentSendFailure, IDEMPOTENCY_TIMEOUT_TICKS, RecentPaymentDetails};
+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;
 use crate::ln::msgs::ChannelMessageHandler;
 use crate::ln::outbound_payment::Retry;
 use crate::routing::gossip::{EffectiveCapacity, RoutingFees};
-use crate::routing::router::{get_route, PaymentParameters, Route, RouteHint, RouteHintHop, RouteHop, RouteParameters};
+use crate::routing::router::{get_route, Path, PaymentParameters, Route, Router, RouteHint, RouteHintHop, RouteHop, RouteParameters};
 use crate::routing::scoring::ChannelUsage;
-use crate::util::events::{ClosureReason, Event, HTLCDestination, MessageSendEvent, MessageSendEventsProvider, PathFailure};
 use crate::util::test_utils;
 use crate::util::errors::APIError;
 use crate::util::ser::Writeable;
+use crate::util::string::UntrustedString;
 
 use bitcoin::{Block, BlockHeader, TxMerkleNode};
 use bitcoin::hashes::Hash;
@@ -58,12 +59,12 @@ fn mpp_failure() {
        let (mut route, payment_hash, _, payment_secret) = get_route_and_payment_hash!(&nodes[0], nodes[3], 100000);
        let path = route.paths[0].clone();
        route.paths.push(path);
-       route.paths[0][0].pubkey = nodes[1].node.get_our_node_id();
-       route.paths[0][0].short_channel_id = chan_1_id;
-       route.paths[0][1].short_channel_id = chan_3_id;
-       route.paths[1][0].pubkey = nodes[2].node.get_our_node_id();
-       route.paths[1][0].short_channel_id = chan_2_id;
-       route.paths[1][1].short_channel_id = chan_4_id;
+       route.paths[0].hops[0].pubkey = nodes[1].node.get_our_node_id();
+       route.paths[0].hops[0].short_channel_id = chan_1_id;
+       route.paths[0].hops[1].short_channel_id = chan_3_id;
+       route.paths[1].hops[0].pubkey = nodes[2].node.get_our_node_id();
+       route.paths[1].hops[0].short_channel_id = chan_2_id;
+       route.paths[1].hops[1].short_channel_id = chan_4_id;
        send_along_route_with_secret(&nodes[0], route, &[&[&nodes[1], &nodes[3]], &[&nodes[2], &nodes[3]]], 200_000, payment_hash, payment_secret);
        fail_payment_along_route(&nodes[0], &[&[&nodes[1], &nodes[3]], &[&nodes[2], &nodes[3]]], false, payment_hash);
 }
@@ -86,12 +87,12 @@ fn mpp_retry() {
        let (mut route, payment_hash, payment_preimage, payment_secret) = get_route_and_payment_hash!(nodes[0], nodes[3], amt_msat);
        let path = route.paths[0].clone();
        route.paths.push(path);
-       route.paths[0][0].pubkey = nodes[1].node.get_our_node_id();
-       route.paths[0][0].short_channel_id = chan_1_update.contents.short_channel_id;
-       route.paths[0][1].short_channel_id = chan_3_update.contents.short_channel_id;
-       route.paths[1][0].pubkey = nodes[2].node.get_our_node_id();
-       route.paths[1][0].short_channel_id = chan_2_update.contents.short_channel_id;
-       route.paths[1][1].short_channel_id = chan_4_update.contents.short_channel_id;
+       route.paths[0].hops[0].pubkey = nodes[1].node.get_our_node_id();
+       route.paths[0].hops[0].short_channel_id = chan_1_update.contents.short_channel_id;
+       route.paths[0].hops[1].short_channel_id = chan_3_update.contents.short_channel_id;
+       route.paths[1].hops[0].pubkey = nodes[2].node.get_our_node_id();
+       route.paths[1].hops[0].short_channel_id = chan_2_update.contents.short_channel_id;
+       route.paths[1].hops[1].short_channel_id = chan_4_update.contents.short_channel_id;
 
        // Initiate the MPP payment.
        let payment_id = PaymentId(payment_hash.0);
@@ -101,7 +102,8 @@ fn mpp_retry() {
        };
 
        nodes[0].router.expect_find_route(route_params.clone(), Ok(route.clone()));
-       nodes[0].node.send_payment_with_retry(payment_hash, &Some(payment_secret), payment_id, route_params.clone(), Retry::Attempts(1)).unwrap();
+       nodes[0].node.send_payment(payment_hash, RecipientOnionFields::secret_only(payment_secret),
+               payment_id, route_params.clone(), Retry::Attempts(1)).unwrap();
        check_added_monitors!(nodes[0], 2); // one monitor per path
        let mut events = nodes[0].node.get_and_clear_pending_msg_events();
        assert_eq!(events.len(), 2);
@@ -175,15 +177,16 @@ fn do_mpp_receive_timeout(send_partial_mpp: bool) {
        let (mut route, payment_hash, payment_preimage, payment_secret) = get_route_and_payment_hash!(nodes[0], nodes[3], 100_000);
        let path = route.paths[0].clone();
        route.paths.push(path);
-       route.paths[0][0].pubkey = nodes[1].node.get_our_node_id();
-       route.paths[0][0].short_channel_id = chan_1_update.contents.short_channel_id;
-       route.paths[0][1].short_channel_id = chan_3_update.contents.short_channel_id;
-       route.paths[1][0].pubkey = nodes[2].node.get_our_node_id();
-       route.paths[1][0].short_channel_id = chan_2_update.contents.short_channel_id;
-       route.paths[1][1].short_channel_id = chan_4_update.contents.short_channel_id;
+       route.paths[0].hops[0].pubkey = nodes[1].node.get_our_node_id();
+       route.paths[0].hops[0].short_channel_id = chan_1_update.contents.short_channel_id;
+       route.paths[0].hops[1].short_channel_id = chan_3_update.contents.short_channel_id;
+       route.paths[1].hops[0].pubkey = nodes[2].node.get_our_node_id();
+       route.paths[1].hops[0].short_channel_id = chan_2_update.contents.short_channel_id;
+       route.paths[1].hops[1].short_channel_id = chan_4_update.contents.short_channel_id;
 
        // Initiate the MPP payment.
-       nodes[0].node.send_payment(&route, payment_hash, &Some(payment_secret), PaymentId(payment_hash.0)).unwrap();
+       nodes[0].node.send_payment_with_route(&route, payment_hash,
+               RecipientOnionFields::secret_only(payment_secret), PaymentId(payment_hash.0)).unwrap();
        check_added_monitors!(nodes[0], 2); // one monitor per path
        let mut events = nodes[0].node.get_and_clear_pending_msg_events();
        assert_eq!(events.len(), 2);
@@ -255,8 +258,9 @@ fn no_pending_leak_on_initial_send_failure() {
        nodes[0].node.peer_disconnected(&nodes[1].node.get_our_node_id());
        nodes[1].node.peer_disconnected(&nodes[0].node.get_our_node_id());
 
-       unwrap_send_err!(nodes[0].node.send_payment(&route, payment_hash, &Some(payment_secret), PaymentId(payment_hash.0)),
-               true, APIError::ChannelUnavailable { ref err },
+       unwrap_send_err!(nodes[0].node.send_payment_with_route(&route, payment_hash,
+                       RecipientOnionFields::secret_only(payment_secret), PaymentId(payment_hash.0)
+               ), true, APIError::ChannelUnavailable { ref err },
                assert_eq!(err, "Peer for first hop currently disconnected"));
 
        assert!(!nodes[0].node.has_pending_payments());
@@ -297,7 +301,8 @@ fn do_retry_with_no_persist(confirm_before_reload: bool) {
                payment_params: route.payment_params.clone().unwrap(),
                final_value_msat: amt_msat,
        };
-       nodes[0].node.send_payment_with_retry(payment_hash, &Some(payment_secret), PaymentId(payment_hash.0), route_params, Retry::Attempts(1)).unwrap();
+       nodes[0].node.send_payment(payment_hash, RecipientOnionFields::secret_only(payment_secret),
+               PaymentId(payment_hash.0), route_params, Retry::Attempts(1)).unwrap();
        check_added_monitors!(nodes[0], 1);
 
        let mut events = nodes[0].node.get_and_clear_pending_msg_events();
@@ -334,9 +339,15 @@ fn do_retry_with_no_persist(confirm_before_reload: bool) {
        check_closed_event!(nodes[0], 1, ClosureReason::OutdatedChannelManager);
        assert!(nodes[0].node.list_channels().is_empty());
        assert!(nodes[0].node.has_pending_payments());
-       let as_broadcasted_txn = nodes[0].tx_broadcaster.txn_broadcasted.lock().unwrap().split_off(0);
-       assert_eq!(as_broadcasted_txn.len(), 1);
-       assert_eq!(as_broadcasted_txn[0], as_commitment_tx);
+       nodes[0].node.timer_tick_occurred();
+       if !confirm_before_reload {
+               let as_broadcasted_txn = nodes[0].tx_broadcaster.txn_broadcasted.lock().unwrap().split_off(0);
+               assert_eq!(as_broadcasted_txn.len(), 1);
+               assert_eq!(as_broadcasted_txn[0].txid(), as_commitment_tx.txid());
+       } else {
+               assert!(nodes[0].tx_broadcaster.txn_broadcasted.lock().unwrap().is_empty());
+       }
+       check_added_monitors!(nodes[0], 1);
 
        nodes[1].node.peer_disconnected(&nodes[0].node.get_our_node_id());
        nodes[0].node.peer_connected(&nodes[1].node.get_our_node_id(), &msgs::Init { features: nodes[1].node.init_features(), remote_network_address: None }, true).unwrap();
@@ -353,7 +364,7 @@ fn do_retry_with_no_persist(confirm_before_reload: bool) {
                MessageSendEvent::HandleError { node_id, action: msgs::ErrorAction::SendErrorMessage { ref msg } } => {
                        assert_eq!(node_id, nodes[1].node.get_our_node_id());
                        nodes[1].node.handle_error(&nodes[0].node.get_our_node_id(), msg);
-                       check_closed_event!(nodes[1], 1, ClosureReason::CounterpartyForceClosed { peer_msg: format!("Got a message for a channel from the wrong node! No such channel for the passed counterparty_node_id {}", &nodes[1].node.get_our_node_id()) });
+                       check_closed_event!(nodes[1], 1, ClosureReason::CounterpartyForceClosed { peer_msg: UntrustedString(format!("Got a message for a channel from the wrong node! No such channel for the passed counterparty_node_id {}", &nodes[1].node.get_our_node_id())) });
                        check_added_monitors!(nodes[1], 1);
                        assert_eq!(nodes[1].tx_broadcaster.txn_broadcasted.lock().unwrap().split_off(0).len(), 1);
                },
@@ -395,9 +406,11 @@ fn do_retry_with_no_persist(confirm_before_reload: bool) {
        mine_transaction(&nodes[0], &bs_htlc_claim_txn[0]);
        expect_payment_sent!(nodes[0], payment_preimage_1);
        connect_blocks(&nodes[0], TEST_FINAL_CLTV*4 + 20);
-       let as_htlc_timeout_txn = nodes[0].tx_broadcaster.txn_broadcasted.lock().unwrap().split_off(0);
-       assert_eq!(as_htlc_timeout_txn.len(), 2);
-       let (first_htlc_timeout_tx, second_htlc_timeout_tx) = (&as_htlc_timeout_txn[0], &as_htlc_timeout_txn[1]);
+       let (first_htlc_timeout_tx, second_htlc_timeout_tx) = {
+               let mut txn = nodes[0].tx_broadcaster.unique_txn_broadcast();
+               assert_eq!(txn.len(), 2);
+               (txn.remove(0), txn.remove(0))
+       };
        check_spends!(first_htlc_timeout_tx, as_commitment_tx);
        check_spends!(second_htlc_timeout_tx, as_commitment_tx);
        if first_htlc_timeout_tx.input[0].previous_output == bs_htlc_claim_txn[0].input[0].previous_output {
@@ -424,7 +437,7 @@ fn do_retry_with_no_persist(confirm_before_reload: bool) {
                let mut new_config = channel.config();
                new_config.forwarding_fee_base_msat += 100_000;
                channel.update_config(&new_config);
-               new_route.paths[0][0].fee_msat += 100_000;
+               new_route.paths[0].hops[0].fee_msat += 100_000;
        }
 
        // Force expiration of the channel's previous config.
@@ -432,14 +445,16 @@ fn do_retry_with_no_persist(confirm_before_reload: bool) {
                nodes[1].node.timer_tick_occurred();
        }
 
-       assert!(nodes[0].node.send_payment(&new_route, payment_hash, &Some(payment_secret), payment_id_1).is_err()); // Shouldn't be allowed to retry a fulfilled payment
-       nodes[0].node.send_payment(&new_route, payment_hash, &Some(payment_secret), PaymentId(payment_hash.0)).unwrap();
+       assert!(nodes[0].node.send_payment_with_route(&new_route, payment_hash, // Shouldn't be allowed to retry a fulfilled payment
+               RecipientOnionFields::secret_only(payment_secret), payment_id_1).is_err());
+       nodes[0].node.send_payment_with_route(&new_route, payment_hash,
+               RecipientOnionFields::secret_only(payment_secret), PaymentId(payment_hash.0)).unwrap();
        check_added_monitors!(nodes[0], 1);
        let mut events = nodes[0].node.get_and_clear_pending_msg_events();
        assert_eq!(events.len(), 1);
        pass_along_path(&nodes[0], &[&nodes[1], &nodes[2]], 1_000_000, payment_hash, Some(payment_secret), events.pop().unwrap(), true, None);
        do_claim_payment_along_route(&nodes[0], &[&[&nodes[1], &nodes[2]]], false, payment_preimage);
-       expect_payment_sent!(nodes[0], payment_preimage, Some(new_route.paths[0][0].fee_msat));
+       expect_payment_sent!(nodes[0], payment_preimage, Some(new_route.paths[0].hops[0].fee_msat));
 }
 
 #[test]
@@ -499,9 +514,11 @@ fn do_test_completed_payment_not_retryable_on_reload(use_dust: bool) {
        // On reload, the ChannelManager should realize it is stale compared to the ChannelMonitor and
        // force-close the channel.
        check_closed_event!(nodes[0], 1, ClosureReason::OutdatedChannelManager);
+       nodes[0].node.timer_tick_occurred();
        assert!(nodes[0].node.list_channels().is_empty());
        assert!(nodes[0].node.has_pending_payments());
        assert_eq!(nodes[0].tx_broadcaster.txn_broadcasted.lock().unwrap().split_off(0).len(), 1);
+       check_added_monitors!(nodes[0], 1);
 
        nodes[0].node.peer_connected(&nodes[1].node.get_our_node_id(), &msgs::Init { features: nodes[1].node.init_features(), remote_network_address: None }, true).unwrap();
        assert!(nodes[0].node.get_and_clear_pending_msg_events().is_empty());
@@ -518,7 +535,7 @@ fn do_test_completed_payment_not_retryable_on_reload(use_dust: bool) {
                MessageSendEvent::HandleError { node_id, action: msgs::ErrorAction::SendErrorMessage { ref msg } } => {
                        assert_eq!(node_id, nodes[1].node.get_our_node_id());
                        nodes[1].node.handle_error(&nodes[0].node.get_our_node_id(), msg);
-                       check_closed_event!(nodes[1], 1, ClosureReason::CounterpartyForceClosed { peer_msg: format!("Got a message for a channel from the wrong node! No such channel for the passed counterparty_node_id {}", &nodes[1].node.get_our_node_id()) });
+                       check_closed_event!(nodes[1], 1, ClosureReason::CounterpartyForceClosed { peer_msg: UntrustedString(format!("Got a message for a channel from the wrong node! No such channel for the passed counterparty_node_id {}", &nodes[1].node.get_our_node_id())) });
                        check_added_monitors!(nodes[1], 1);
                        bs_commitment_tx = nodes[1].tx_broadcaster.txn_broadcasted.lock().unwrap().split_off(0);
                },
@@ -545,8 +562,8 @@ fn do_test_completed_payment_not_retryable_on_reload(use_dust: bool) {
        mine_transaction(&nodes[0], &bs_commitment_tx[0]);
        mine_transaction(&nodes[1], &bs_commitment_tx[0]);
        if !use_dust {
-               connect_blocks(&nodes[0], TEST_FINAL_CLTV - 1 + (MIN_CLTV_EXPIRY_DELTA as u32));
-               connect_blocks(&nodes[1], TEST_FINAL_CLTV - 1 + (MIN_CLTV_EXPIRY_DELTA as u32));
+               connect_blocks(&nodes[0], TEST_FINAL_CLTV + (MIN_CLTV_EXPIRY_DELTA as u32));
+               connect_blocks(&nodes[1], TEST_FINAL_CLTV + (MIN_CLTV_EXPIRY_DELTA as u32));
                let as_htlc_timeout = nodes[0].tx_broadcaster.txn_broadcasted.lock().unwrap().split_off(0);
                check_spends!(as_htlc_timeout[0], bs_commitment_tx[0]);
                assert_eq!(as_htlc_timeout.len(), 1);
@@ -567,7 +584,7 @@ fn do_test_completed_payment_not_retryable_on_reload(use_dust: bool) {
        // If we attempt to retry prior to the HTLC-Timeout (or commitment transaction, for dust HTLCs)
        // confirming, we will fail as it's considered still-pending...
        let (new_route, _, _, _) = get_route_and_payment_hash!(nodes[0], nodes[2], if use_dust { 1_000 } else { 1_000_000 });
-       match nodes[0].node.send_payment(&new_route, payment_hash, &Some(payment_secret), payment_id) {
+       match nodes[0].node.send_payment_with_route(&new_route, payment_hash, RecipientOnionFields::secret_only(payment_secret), payment_id) {
                Err(PaymentSendFailure::DuplicatePayment) => {},
                _ => panic!("Unexpected error")
        }
@@ -585,7 +602,8 @@ fn do_test_completed_payment_not_retryable_on_reload(use_dust: bool) {
        nodes_0_serialized = nodes[0].node.encode();
 
        // After the payment failed, we're free to send it again.
-       assert!(nodes[0].node.send_payment(&new_route, payment_hash, &Some(payment_secret), payment_id).is_ok());
+       assert!(nodes[0].node.send_payment_with_route(&new_route, payment_hash,
+               RecipientOnionFields::secret_only(payment_secret), payment_id).is_ok());
        assert!(!nodes[0].node.get_and_clear_pending_msg_events().is_empty());
 
        reload_node!(nodes[0], test_default_channel_config(), nodes_0_serialized, &[&chan_0_monitor_serialized, &chan_1_monitor_serialized], second_persister, second_new_chain_monitor, second_nodes_0_deserialized);
@@ -595,12 +613,13 @@ fn do_test_completed_payment_not_retryable_on_reload(use_dust: bool) {
 
        // Now resend the payment, delivering the HTLC and actually claiming it this time. This ensures
        // the payment is not (spuriously) listed as still pending.
-       assert!(nodes[0].node.send_payment(&new_route, payment_hash, &Some(payment_secret), payment_id).is_ok());
+       assert!(nodes[0].node.send_payment_with_route(&new_route, payment_hash,
+               RecipientOnionFields::secret_only(payment_secret), payment_id).is_ok());
        check_added_monitors!(nodes[0], 1);
        pass_along_route(&nodes[0], &[&[&nodes[1], &nodes[2]]], if use_dust { 1_000 } else { 1_000_000 }, payment_hash, payment_secret);
        claim_payment(&nodes[0], &[&nodes[1], &nodes[2]], payment_preimage);
 
-       match nodes[0].node.send_payment(&new_route, payment_hash, &Some(payment_secret), payment_id) {
+       match nodes[0].node.send_payment_with_route(&new_route, payment_hash, RecipientOnionFields::secret_only(payment_secret), payment_id) {
                Err(PaymentSendFailure::DuplicatePayment) => {},
                _ => panic!("Unexpected error")
        }
@@ -617,7 +636,7 @@ fn do_test_completed_payment_not_retryable_on_reload(use_dust: bool) {
 
        reconnect_nodes(&nodes[0], &nodes[1], (false, false), (0, 0), (0, 0), (0, 0), (0, 0), (0, 0), (false, false));
 
-       match nodes[0].node.send_payment(&new_route, payment_hash, &Some(payment_secret), payment_id) {
+       match nodes[0].node.send_payment_with_route(&new_route, payment_hash, RecipientOnionFields::secret_only(payment_secret), payment_id) {
                Err(PaymentSendFailure::DuplicatePayment) => {},
                _ => panic!("Unexpected error")
        }
@@ -665,7 +684,7 @@ fn do_test_dup_htlc_onchain_fails_on_reload(persist_manager_post_event: bool, co
        connect_blocks(&nodes[0], TEST_FINAL_CLTV + LATENCY_GRACE_PERIOD_BLOCKS + 1);
        let node_txn = nodes[0].tx_broadcaster.txn_broadcasted.lock().unwrap().split_off(0);
        assert_eq!(node_txn.len(), 3);
-       assert_eq!(node_txn[0], node_txn[1]);
+       assert_eq!(node_txn[0].txid(), node_txn[1].txid());
        check_spends!(node_txn[1], funding_tx);
        check_spends!(node_txn[2], node_txn[1]);
        let timeout_txn = vec![node_txn[2].clone()];
@@ -845,8 +864,9 @@ fn get_ldk_payment_preimage() {
        let route = get_route(
                &nodes[0].node.get_our_node_id(), &payment_params, &nodes[0].network_graph.read_only(),
                Some(&nodes[0].node.list_usable_channels().iter().collect::<Vec<_>>()),
-               amt_msat, TEST_FINAL_CLTV, nodes[0].logger, &scorer, &random_seed_bytes).unwrap();
-       nodes[0].node.send_payment(&route, payment_hash, &Some(payment_secret), PaymentId(payment_hash.0)).unwrap();
+               amt_msat, nodes[0].logger, &scorer, &random_seed_bytes).unwrap();
+       nodes[0].node.send_payment_with_route(&route, payment_hash,
+               RecipientOnionFields::secret_only(payment_secret), PaymentId(payment_hash.0)).unwrap();
        check_added_monitors!(nodes[0], 1);
 
        // Make sure to use `get_payment_preimage`
@@ -933,7 +953,7 @@ fn successful_probe_yields_event() {
        let mut events = nodes[0].node.get_and_clear_pending_events();
        assert_eq!(events.len(), 1);
        match events.drain(..).next().unwrap() {
-               crate::util::events::Event::ProbeSuccessful { payment_id: ev_pid, payment_hash: ev_ph, .. } => {
+               crate::events::Event::ProbeSuccessful { payment_id: ev_pid, payment_hash: ev_ph, .. } => {
                        assert_eq!(payment_id, ev_pid);
                        assert_eq!(payment_hash, ev_ph);
                },
@@ -954,7 +974,7 @@ fn failed_probe_yields_event() {
 
        let payment_params = PaymentParameters::from_node_id(nodes[2].node.get_our_node_id(), 42);
 
-       let (route, _, _, _) = get_route_and_payment_hash!(&nodes[0], nodes[2], &payment_params, 9_998_000, 42);
+       let (route, _, _, _) = get_route_and_payment_hash!(&nodes[0], nodes[2], &payment_params, 9_998_000);
 
        let (payment_hash, payment_id) = nodes[0].node.send_probe(route.paths[0].clone()).unwrap();
 
@@ -979,7 +999,7 @@ fn failed_probe_yields_event() {
        let mut events = nodes[0].node.get_and_clear_pending_events();
        assert_eq!(events.len(), 1);
        match events.drain(..).next().unwrap() {
-               crate::util::events::Event::ProbeFailed { payment_id: ev_pid, payment_hash: ev_ph, .. } => {
+               crate::events::Event::ProbeFailed { payment_id: ev_pid, payment_hash: ev_ph, .. } => {
                        assert_eq!(payment_id, ev_pid);
                        assert_eq!(payment_hash, ev_ph);
                },
@@ -1003,7 +1023,7 @@ fn onchain_failed_probe_yields_event() {
        let payment_params = PaymentParameters::from_node_id(nodes[2].node.get_our_node_id(), 42);
 
        // Send a dust HTLC, which will be treated as if it timed out once the channel hits the chain.
-       let (route, _, _, _) = get_route_and_payment_hash!(&nodes[0], nodes[2], &payment_params, 1_000, 42);
+       let (route, _, _, _) = get_route_and_payment_hash!(&nodes[0], nodes[2], &payment_params, 1_000);
        let (payment_hash, payment_id) = nodes[0].node.send_probe(route.paths[0].clone()).unwrap();
 
        // node[0] -- update_add_htlcs -> node[1]
@@ -1060,7 +1080,8 @@ fn claimed_send_payment_idempotent() {
                () => {
                        // If we try to resend a new payment with a different payment_hash but with the same
                        // payment_id, it should be rejected.
-                       let send_result = nodes[0].node.send_payment(&route, second_payment_hash, &Some(second_payment_secret), payment_id);
+                       let send_result = nodes[0].node.send_payment_with_route(&route, second_payment_hash,
+                               RecipientOnionFields::secret_only(second_payment_secret), payment_id);
                        match send_result {
                                Err(PaymentSendFailure::DuplicatePayment) => {},
                                _ => panic!("Unexpected send result: {:?}", send_result),
@@ -1068,7 +1089,8 @@ fn claimed_send_payment_idempotent() {
 
                        // Further, if we try to send a spontaneous payment with the same payment_id it should
                        // also be rejected.
-                       let send_result = nodes[0].node.send_spontaneous_payment(&route, None, payment_id);
+                       let send_result = nodes[0].node.send_spontaneous_payment(
+                               &route, None, RecipientOnionFields::spontaneous_empty(), payment_id);
                        match send_result {
                                Err(PaymentSendFailure::DuplicatePayment) => {},
                                _ => panic!("Unexpected send result: {:?}", send_result),
@@ -1108,7 +1130,8 @@ fn claimed_send_payment_idempotent() {
                nodes[0].node.timer_tick_occurred();
        }
 
-       nodes[0].node.send_payment(&route, second_payment_hash, &Some(second_payment_secret), payment_id).unwrap();
+       nodes[0].node.send_payment_with_route(&route, second_payment_hash,
+               RecipientOnionFields::secret_only(second_payment_secret), payment_id).unwrap();
        check_added_monitors!(nodes[0], 1);
        pass_along_route(&nodes[0], &[&[&nodes[1]]], 100_000, second_payment_hash, second_payment_secret);
        claim_payment(&nodes[0], &[&nodes[1]], second_payment_preimage);
@@ -1132,7 +1155,8 @@ fn abandoned_send_payment_idempotent() {
                () => {
                        // If we try to resend a new payment with a different payment_hash but with the same
                        // payment_id, it should be rejected.
-                       let send_result = nodes[0].node.send_payment(&route, second_payment_hash, &Some(second_payment_secret), payment_id);
+                       let send_result = nodes[0].node.send_payment_with_route(&route, second_payment_hash,
+                               RecipientOnionFields::secret_only(second_payment_secret), payment_id);
                        match send_result {
                                Err(PaymentSendFailure::DuplicatePayment) => {},
                                _ => panic!("Unexpected send result: {:?}", send_result),
@@ -1140,7 +1164,8 @@ fn abandoned_send_payment_idempotent() {
 
                        // Further, if we try to send a spontaneous payment with the same payment_id it should
                        // also be rejected.
-                       let send_result = nodes[0].node.send_spontaneous_payment(&route, None, payment_id);
+                       let send_result = nodes[0].node.send_spontaneous_payment(
+                               &route, None, RecipientOnionFields::spontaneous_empty(), payment_id);
                        match send_result {
                                Err(PaymentSendFailure::DuplicatePayment) => {},
                                _ => panic!("Unexpected send result: {:?}", send_result),
@@ -1160,11 +1185,12 @@ fn abandoned_send_payment_idempotent() {
        }
        check_send_rejected!();
 
-       pass_failed_payment_back(&nodes[0], &[&[&nodes[1]]], false, first_payment_hash);
+       pass_failed_payment_back(&nodes[0], &[&[&nodes[1]]], false, first_payment_hash, PaymentFailureReason::RecipientRejected);
 
        // However, we can reuse the PaymentId immediately after we `abandon_payment` upon passing the
        // failed payment back.
-       nodes[0].node.send_payment(&route, second_payment_hash, &Some(second_payment_secret), payment_id).unwrap();
+       nodes[0].node.send_payment_with_route(&route, second_payment_hash,
+               RecipientOnionFields::secret_only(second_payment_secret), payment_id).unwrap();
        check_added_monitors!(nodes[0], 1);
        pass_along_route(&nodes[0], &[&[&nodes[1]]], 100_000, second_payment_hash, second_payment_secret);
        claim_payment(&nodes[0], &[&nodes[1]], second_payment_preimage);
@@ -1313,9 +1339,11 @@ fn test_holding_cell_inflight_htlcs() {
        // Queue up two payments - one will be delivered right away, one immediately goes into the
        // holding cell as nodes[0] is AwaitingRAA.
        {
-               nodes[0].node.send_payment(&route, payment_hash_1, &Some(payment_secret_1), PaymentId(payment_hash_1.0)).unwrap();
+               nodes[0].node.send_payment_with_route(&route, payment_hash_1,
+                       RecipientOnionFields::secret_only(payment_secret_1), PaymentId(payment_hash_1.0)).unwrap();
                check_added_monitors!(nodes[0], 1);
-               nodes[0].node.send_payment(&route, payment_hash_2, &Some(payment_secret_2), PaymentId(payment_hash_2.0)).unwrap();
+               nodes[0].node.send_payment_with_route(&route, payment_hash_2,
+                       RecipientOnionFields::secret_only(payment_secret_2), PaymentId(payment_hash_2.0)).unwrap();
                check_added_monitors!(nodes[0], 0);
        }
 
@@ -1390,12 +1418,12 @@ fn do_test_intercepted_payment(test: InterceptTest) {
        let route = get_route(
                &nodes[0].node.get_our_node_id(), &route_params.payment_params,
                &nodes[0].network_graph.read_only(), None, route_params.final_value_msat,
-               route_params.payment_params.final_cltv_expiry_delta, nodes[0].logger, &scorer,
-               &random_seed_bytes,
+               nodes[0].logger, &scorer, &random_seed_bytes,
        ).unwrap();
 
        let (payment_hash, payment_secret) = nodes[2].node.create_inbound_payment(Some(amt_msat), 60 * 60, None).unwrap();
-       nodes[0].node.send_payment(&route, payment_hash, &Some(payment_secret), PaymentId(payment_hash.0)).unwrap();
+       nodes[0].node.send_payment_with_route(&route, payment_hash,
+               RecipientOnionFields::secret_only(payment_secret), PaymentId(payment_hash.0)).unwrap();
        let payment_event = {
                {
                        let mut added_monitors = nodes[0].chain_monitor.added_monitors.lock().unwrap();
@@ -1413,7 +1441,7 @@ fn do_test_intercepted_payment(test: InterceptTest) {
        let events = nodes[1].node.get_and_clear_pending_events();
        assert_eq!(events.len(), 1);
        let (intercept_id, expected_outbound_amount_msat) = match events[0] {
-               crate::util::events::Event::HTLCIntercepted {
+               crate::events::Event::HTLCIntercepted {
                        intercept_id, expected_outbound_amount_msat, payment_hash: pmt_hash, inbound_amount_msat, requested_next_hop_scid: short_channel_id
                } => {
                        assert_eq!(pmt_hash, payment_hash);
@@ -1630,7 +1658,8 @@ fn do_automatic_retries(test: AutoRetry) {
 
        if test == AutoRetry::Success {
                // Test that we can succeed on the first retry.
-               nodes[0].node.send_payment_with_retry(payment_hash, &Some(payment_secret), PaymentId(payment_hash.0), route_params, Retry::Attempts(1)).unwrap();
+               nodes[0].node.send_payment(payment_hash, RecipientOnionFields::secret_only(payment_secret),
+                       PaymentId(payment_hash.0), route_params, Retry::Attempts(1)).unwrap();
                pass_failed_attempt_with_retry_along_path!(channel_id_2, true);
 
                // Open a new channel with liquidity on the second hop so we can find a route for the retry
@@ -1645,7 +1674,9 @@ fn do_automatic_retries(test: AutoRetry) {
                pass_along_path(&nodes[0], &[&nodes[1], &nodes[2]], amt_msat, payment_hash, Some(payment_secret), msg_events.pop().unwrap(), true, None);
                claim_payment_along_route(&nodes[0], &[&[&nodes[1], &nodes[2]]], false, payment_preimage);
        } else if test == AutoRetry::Spontaneous {
-               nodes[0].node.send_spontaneous_payment_with_retry(Some(payment_preimage), PaymentId(payment_hash.0), route_params, Retry::Attempts(1)).unwrap();
+               nodes[0].node.send_spontaneous_payment_with_retry(Some(payment_preimage),
+                       RecipientOnionFields::spontaneous_empty(), PaymentId(payment_hash.0), route_params,
+                       Retry::Attempts(1)).unwrap();
                pass_failed_attempt_with_retry_along_path!(channel_id_2, true);
 
                // Open a new channel with liquidity on the second hop so we can find a route for the retry
@@ -1661,7 +1692,8 @@ fn do_automatic_retries(test: AutoRetry) {
                claim_payment_along_route(&nodes[0], &[&[&nodes[1], &nodes[2]]], false, payment_preimage);
        } else if test == AutoRetry::FailAttempts {
                // Ensure ChannelManager will not retry a payment if it has run out of payment attempts.
-               nodes[0].node.send_payment_with_retry(payment_hash, &Some(payment_secret), PaymentId(payment_hash.0), route_params, Retry::Attempts(1)).unwrap();
+               nodes[0].node.send_payment(payment_hash, RecipientOnionFields::secret_only(payment_secret),
+                       PaymentId(payment_hash.0), route_params, Retry::Attempts(1)).unwrap();
                pass_failed_attempt_with_retry_along_path!(channel_id_2, true);
 
                // Open a new channel with no liquidity on the second hop so we can find a (bad) route for
@@ -1679,7 +1711,8 @@ fn do_automatic_retries(test: AutoRetry) {
        } else if test == AutoRetry::FailTimeout {
                #[cfg(not(feature = "no-std"))] {
                        // Ensure ChannelManager will not retry a payment if it times out due to Retry::Timeout.
-                       nodes[0].node.send_payment_with_retry(payment_hash, &Some(payment_secret), PaymentId(payment_hash.0), route_params, Retry::Timeout(Duration::from_secs(60))).unwrap();
+                       nodes[0].node.send_payment(payment_hash, RecipientOnionFields::secret_only(payment_secret),
+                               PaymentId(payment_hash.0), route_params, Retry::Timeout(Duration::from_secs(60))).unwrap();
                        pass_failed_attempt_with_retry_along_path!(channel_id_2, true);
 
                        // Advance the time so the second attempt fails due to timeout.
@@ -1693,9 +1726,10 @@ fn do_automatic_retries(test: AutoRetry) {
                        let mut events = nodes[0].node.get_and_clear_pending_events();
                        assert_eq!(events.len(), 1);
                        match events[0] {
-                               Event::PaymentFailed { payment_hash: ref ev_payment_hash, payment_id: ref ev_payment_id } => {
+                               Event::PaymentFailed { payment_hash: ref ev_payment_hash, payment_id: ref ev_payment_id, reason: ref ev_reason } => {
                                        assert_eq!(payment_hash, *ev_payment_hash);
                                        assert_eq!(PaymentId(payment_hash.0), *ev_payment_id);
+                                       assert_eq!(PaymentFailureReason::RetriesExhausted, ev_reason.unwrap());
                                },
                                _ => panic!("Unexpected event"),
                        }
@@ -1703,7 +1737,8 @@ fn do_automatic_retries(test: AutoRetry) {
        } else if test == AutoRetry::FailOnRestart {
                // Ensure ChannelManager will not retry a payment after restart, even if there were retry
                // attempts remaining prior to restart.
-               nodes[0].node.send_payment_with_retry(payment_hash, &Some(payment_secret), PaymentId(payment_hash.0), route_params, Retry::Attempts(2)).unwrap();
+               nodes[0].node.send_payment(payment_hash, RecipientOnionFields::secret_only(payment_secret),
+                       PaymentId(payment_hash.0), route_params, Retry::Attempts(2)).unwrap();
                pass_failed_attempt_with_retry_along_path!(channel_id_2, true);
 
                // Open a new channel with no liquidity on the second hop so we can find a (bad) route for
@@ -1728,14 +1763,16 @@ fn do_automatic_retries(test: AutoRetry) {
                let mut events = nodes[0].node.get_and_clear_pending_events();
                assert_eq!(events.len(), 1);
                match events[0] {
-                       Event::PaymentFailed { payment_hash: ref ev_payment_hash, payment_id: ref ev_payment_id } => {
+                       Event::PaymentFailed { payment_hash: ref ev_payment_hash, payment_id: ref ev_payment_id, reason: ref ev_reason } => {
                                assert_eq!(payment_hash, *ev_payment_hash);
                                assert_eq!(PaymentId(payment_hash.0), *ev_payment_id);
+                               assert_eq!(PaymentFailureReason::RetriesExhausted, ev_reason.unwrap());
                        },
                        _ => panic!("Unexpected event"),
                }
        } else if test == AutoRetry::FailOnRetry {
-               nodes[0].node.send_payment_with_retry(payment_hash, &Some(payment_secret), PaymentId(payment_hash.0), route_params, Retry::Attempts(1)).unwrap();
+               nodes[0].node.send_payment(payment_hash, RecipientOnionFields::secret_only(payment_secret),
+                       PaymentId(payment_hash.0), route_params, Retry::Attempts(1)).unwrap();
                pass_failed_attempt_with_retry_along_path!(channel_id_2, true);
 
                // We retry payments in `process_pending_htlc_forwards`. Since our channel closed, we should
@@ -1747,9 +1784,10 @@ fn do_automatic_retries(test: AutoRetry) {
                let mut events = nodes[0].node.get_and_clear_pending_events();
                assert_eq!(events.len(), 1);
                match events[0] {
-                       Event::PaymentFailed { payment_hash: ref ev_payment_hash, payment_id: ref ev_payment_id } => {
+                       Event::PaymentFailed { payment_hash: ref ev_payment_hash, payment_id: ref ev_payment_id, reason: ref ev_reason } => {
                                assert_eq!(payment_hash, *ev_payment_hash);
                                assert_eq!(PaymentId(payment_hash.0), *ev_payment_id);
+                               assert_eq!(PaymentFailureReason::RouteNotFound, ev_reason.unwrap());
                        },
                        _ => panic!("Unexpected event"),
                }
@@ -1800,56 +1838,56 @@ fn auto_retry_partial_failure() {
        // Configure the initial send, retry1 and retry2's paths.
        let send_route = Route {
                paths: vec![
-                       vec![RouteHop {
+                       Path { hops: vec![RouteHop {
                                pubkey: nodes[1].node.get_our_node_id(),
                                node_features: nodes[1].node.node_features(),
                                short_channel_id: chan_1_id,
                                channel_features: nodes[1].node.channel_features(),
                                fee_msat: amt_msat / 2,
                                cltv_expiry_delta: 100,
-                       }],
-                       vec![RouteHop {
+                       }], blinded_tail: None },
+                       Path { hops: vec![RouteHop {
                                pubkey: nodes[1].node.get_our_node_id(),
                                node_features: nodes[1].node.node_features(),
                                short_channel_id: chan_2_id,
                                channel_features: nodes[1].node.channel_features(),
                                fee_msat: amt_msat / 2,
                                cltv_expiry_delta: 100,
-                       }],
+                       }], blinded_tail: None },
                ],
                payment_params: Some(route_params.payment_params.clone()),
        };
        let retry_1_route = Route {
                paths: vec![
-                       vec![RouteHop {
+                       Path { hops: vec![RouteHop {
                                pubkey: nodes[1].node.get_our_node_id(),
                                node_features: nodes[1].node.node_features(),
                                short_channel_id: chan_1_id,
                                channel_features: nodes[1].node.channel_features(),
                                fee_msat: amt_msat / 4,
                                cltv_expiry_delta: 100,
-                       }],
-                       vec![RouteHop {
+                       }], blinded_tail: None },
+                       Path { hops: vec![RouteHop {
                                pubkey: nodes[1].node.get_our_node_id(),
                                node_features: nodes[1].node.node_features(),
                                short_channel_id: chan_3_id,
                                channel_features: nodes[1].node.channel_features(),
                                fee_msat: amt_msat / 4,
                                cltv_expiry_delta: 100,
-                       }],
+                       }], blinded_tail: None },
                ],
                payment_params: Some(route_params.payment_params.clone()),
        };
        let retry_2_route = Route {
                paths: vec![
-                       vec![RouteHop {
+                       Path { hops: vec![RouteHop {
                                pubkey: nodes[1].node.get_our_node_id(),
                                node_features: nodes[1].node.node_features(),
                                short_channel_id: chan_1_id,
                                channel_features: nodes[1].node.channel_features(),
                                fee_msat: amt_msat / 4,
                                cltv_expiry_delta: 100,
-                       }],
+                       }], blinded_tail: None },
                ],
                payment_params: Some(route_params.payment_params.clone()),
        };
@@ -1866,7 +1904,8 @@ fn auto_retry_partial_failure() {
                }, Ok(retry_2_route));
 
        // Send a payment that will partially fail on send, then partially fail on retry, then succeed.
-       nodes[0].node.send_payment_with_retry(payment_hash, &Some(payment_secret), PaymentId(payment_hash.0), route_params, Retry::Attempts(3)).unwrap();
+       nodes[0].node.send_payment(payment_hash, RecipientOnionFields::secret_only(payment_secret),
+               PaymentId(payment_hash.0), route_params, Retry::Attempts(3)).unwrap();
        let closed_chan_events = nodes[0].node.get_and_clear_pending_events();
        assert_eq!(closed_chan_events.len(), 4);
        match closed_chan_events[0] {
@@ -1999,7 +2038,8 @@ fn auto_retry_zero_attempts_send_error() {
        };
 
        chanmon_cfgs[0].persister.set_update_ret(ChannelMonitorUpdateStatus::PermanentFailure);
-       nodes[0].node.send_payment_with_retry(payment_hash, &Some(payment_secret), PaymentId(payment_hash.0), route_params, Retry::Attempts(0)).unwrap();
+       nodes[0].node.send_payment(payment_hash, RecipientOnionFields::secret_only(payment_secret),
+               PaymentId(payment_hash.0), route_params, Retry::Attempts(0)).unwrap();
        assert_eq!(nodes[0].node.get_and_clear_pending_msg_events().len(), 2); // channel close messages
        let events = nodes[0].node.get_and_clear_pending_events();
        assert_eq!(events.len(), 3);
@@ -2037,7 +2077,8 @@ fn fails_paying_after_rejected_by_payee() {
                final_value_msat: amt_msat,
        };
 
-       nodes[0].node.send_payment_with_retry(payment_hash, &Some(payment_secret), PaymentId(payment_hash.0), route_params, Retry::Attempts(1)).unwrap();
+       nodes[0].node.send_payment(payment_hash, RecipientOnionFields::secret_only(payment_secret),
+               PaymentId(payment_hash.0), route_params, Retry::Attempts(1)).unwrap();
        check_added_monitors!(nodes[0], 1);
        let mut events = nodes[0].node.get_and_clear_pending_msg_events();
        assert_eq!(events.len(), 1);
@@ -2050,7 +2091,7 @@ fn fails_paying_after_rejected_by_payee() {
 
        nodes[1].node.fail_htlc_backwards(&payment_hash);
        expect_pending_htlcs_forwardable_and_htlc_handling_failed!(nodes[1], [HTLCDestination::FailedPayment { payment_hash }]);
-       pass_failed_payment_back(&nodes[0], &[&[&nodes[1]]], false, payment_hash);
+       pass_failed_payment_back(&nodes[0], &[&[&nodes[1]]], false, payment_hash, PaymentFailureReason::RecipientRejected);
 }
 
 #[test]
@@ -2086,29 +2127,29 @@ fn retry_multi_path_single_failed_payment() {
        let chans = nodes[0].node.list_usable_channels();
        let mut route = Route {
                paths: vec![
-                       vec![RouteHop {
+                       Path { hops: vec![RouteHop {
                                pubkey: nodes[1].node.get_our_node_id(),
                                node_features: nodes[1].node.node_features(),
                                short_channel_id: chans[0].short_channel_id.unwrap(),
                                channel_features: nodes[1].node.channel_features(),
                                fee_msat: 10_000,
                                cltv_expiry_delta: 100,
-                       }],
-                       vec![RouteHop {
+                       }], blinded_tail: None },
+                       Path { hops: vec![RouteHop {
                                pubkey: nodes[1].node.get_our_node_id(),
                                node_features: nodes[1].node.node_features(),
                                short_channel_id: chans[1].short_channel_id.unwrap(),
                                channel_features: nodes[1].node.channel_features(),
                                fee_msat: 100_000_001, // Our default max-HTLC-value is 10% of the channel value, which this is one more than
                                cltv_expiry_delta: 100,
-                       }],
+                       }], blinded_tail: None },
                ],
                payment_params: Some(payment_params),
        };
        nodes[0].router.expect_find_route(route_params.clone(), Ok(route.clone()));
        // On retry, split the payment across both channels.
-       route.paths[0][0].fee_msat = 50_000_001;
-       route.paths[1][0].fee_msat = 50_000_000;
+       route.paths[0].hops[0].fee_msat = 50_000_001;
+       route.paths[1].hops[0].fee_msat = 50_000_000;
        let mut pay_params = route.payment_params.clone().unwrap();
        pay_params.previously_failed_channels.push(chans[1].short_channel_id.unwrap());
        nodes[0].router.expect_find_route(RouteParameters {
@@ -2128,7 +2169,8 @@ fn retry_multi_path_single_failed_payment() {
                scorer.expect_usage(chans[1].short_channel_id.unwrap(), ChannelUsage { amount_msat: 50_000_000, inflight_htlc_msat: 0, effective_capacity: EffectiveCapacity::Unknown });
        }
 
-       nodes[0].node.send_payment_with_retry(payment_hash, &Some(payment_secret), PaymentId(payment_hash.0), route_params, Retry::Attempts(1)).unwrap();
+       nodes[0].node.send_payment(payment_hash, RecipientOnionFields::secret_only(payment_secret),
+               PaymentId(payment_hash.0), route_params, Retry::Attempts(1)).unwrap();
        let events = nodes[0].node.get_and_clear_pending_events();
        assert_eq!(events.len(), 1);
        match events[0] {
@@ -2137,7 +2179,7 @@ fn retry_multi_path_single_failed_payment() {
                        short_channel_id: Some(expected_scid), .. } =>
                {
                        assert_eq!(payment_hash, ev_payment_hash);
-                       assert_eq!(expected_scid, route.paths[1][0].short_channel_id);
+                       assert_eq!(expected_scid, route.paths[1].hops[0].short_channel_id);
                        assert!(err_msg.contains("max HTLC"));
                },
                _ => panic!("Unexpected event"),
@@ -2179,30 +2221,31 @@ fn immediate_retry_on_failure() {
        let chans = nodes[0].node.list_usable_channels();
        let mut route = Route {
                paths: vec![
-                       vec![RouteHop {
+                       Path { hops: vec![RouteHop {
                                pubkey: nodes[1].node.get_our_node_id(),
                                node_features: nodes[1].node.node_features(),
                                short_channel_id: chans[0].short_channel_id.unwrap(),
                                channel_features: nodes[1].node.channel_features(),
                                fee_msat: 100_000_001, // Our default max-HTLC-value is 10% of the channel value, which this is one more than
                                cltv_expiry_delta: 100,
-                       }],
+                       }], blinded_tail: None },
                ],
                payment_params: Some(PaymentParameters::from_node_id(nodes[1].node.get_our_node_id(), TEST_FINAL_CLTV)),
        };
        nodes[0].router.expect_find_route(route_params.clone(), Ok(route.clone()));
        // On retry, split the payment across both channels.
        route.paths.push(route.paths[0].clone());
-       route.paths[0][0].short_channel_id = chans[1].short_channel_id.unwrap();
-       route.paths[0][0].fee_msat = 50_000_000;
-       route.paths[1][0].fee_msat = 50_000_001;
+       route.paths[0].hops[0].short_channel_id = chans[1].short_channel_id.unwrap();
+       route.paths[0].hops[0].fee_msat = 50_000_000;
+       route.paths[1].hops[0].fee_msat = 50_000_001;
        let mut pay_params = route_params.payment_params.clone();
        pay_params.previously_failed_channels.push(chans[0].short_channel_id.unwrap());
        nodes[0].router.expect_find_route(RouteParameters {
                        payment_params: pay_params, final_value_msat: amt_msat,
                }, Ok(route.clone()));
 
-       nodes[0].node.send_payment_with_retry(payment_hash, &Some(payment_secret), PaymentId(payment_hash.0), route_params, Retry::Attempts(1)).unwrap();
+       nodes[0].node.send_payment(payment_hash, RecipientOnionFields::secret_only(payment_secret),
+               PaymentId(payment_hash.0), route_params, Retry::Attempts(1)).unwrap();
        let events = nodes[0].node.get_and_clear_pending_events();
        assert_eq!(events.len(), 1);
        match events[0] {
@@ -2211,7 +2254,7 @@ fn immediate_retry_on_failure() {
                        short_channel_id: Some(expected_scid), .. } =>
                {
                        assert_eq!(payment_hash, ev_payment_hash);
-                       assert_eq!(expected_scid, route.paths[1][0].short_channel_id);
+                       assert_eq!(expected_scid, route.paths[1].hops[0].short_channel_id);
                        assert!(err_msg.contains("max HTLC"));
                },
                _ => panic!("Unexpected event"),
@@ -2266,7 +2309,7 @@ fn no_extra_retries_on_back_to_back_fail() {
 
        let mut route = Route {
                paths: vec![
-                       vec![RouteHop {
+                       Path { hops: vec![RouteHop {
                                pubkey: nodes[1].node.get_our_node_id(),
                                node_features: nodes[1].node.node_features(),
                                short_channel_id: chan_1_scid,
@@ -2280,8 +2323,8 @@ fn no_extra_retries_on_back_to_back_fail() {
                                channel_features: nodes[2].node.channel_features(),
                                fee_msat: 100_000_000,
                                cltv_expiry_delta: 100,
-                       }],
-                       vec![RouteHop {
+                       }], blinded_tail: None },
+                       Path { hops: vec![RouteHop {
                                pubkey: nodes[1].node.get_our_node_id(),
                                node_features: nodes[1].node.node_features(),
                                short_channel_id: chan_1_scid,
@@ -2295,7 +2338,7 @@ fn no_extra_retries_on_back_to_back_fail() {
                                channel_features: nodes[2].node.channel_features(),
                                fee_msat: 100_000_000,
                                cltv_expiry_delta: 100,
-                       }]
+                       }], blinded_tail: None }
                ],
                payment_params: Some(PaymentParameters::from_node_id(nodes[2].node.get_our_node_id(), TEST_FINAL_CLTV)),
        };
@@ -2304,13 +2347,14 @@ fn no_extra_retries_on_back_to_back_fail() {
        second_payment_params.previously_failed_channels = vec![chan_2_scid, chan_2_scid];
        // On retry, we'll only return one path
        route.paths.remove(1);
-       route.paths[0][1].fee_msat = amt_msat;
+       route.paths[0].hops[1].fee_msat = amt_msat;
        nodes[0].router.expect_find_route(RouteParameters {
                        payment_params: second_payment_params,
                        final_value_msat: amt_msat,
                }, Ok(route.clone()));
 
-       nodes[0].node.send_payment_with_retry(payment_hash, &Some(payment_secret), PaymentId(payment_hash.0), route_params, Retry::Attempts(1)).unwrap();
+       nodes[0].node.send_payment(payment_hash, RecipientOnionFields::secret_only(payment_secret),
+               PaymentId(payment_hash.0), route_params, Retry::Attempts(1)).unwrap();
        let htlc_updates = SendEvent::from_node(&nodes[0]);
        check_added_monitors!(nodes[0], 1);
        assert_eq!(htlc_updates.msgs.len(), 1);
@@ -2423,9 +2467,10 @@ fn no_extra_retries_on_back_to_back_fail() {
                _ => panic!("Unexpected event"),
        }
        match events[1] {
-               Event::PaymentFailed { payment_hash: ref ev_payment_hash, payment_id: ref ev_payment_id } => {
+               Event::PaymentFailed { payment_hash: ref ev_payment_hash, payment_id: ref ev_payment_id, reason: ref ev_reason } => {
                        assert_eq!(payment_hash, *ev_payment_hash);
                        assert_eq!(PaymentId(payment_hash.0), *ev_payment_id);
+                       assert_eq!(PaymentFailureReason::RetriesExhausted, ev_reason.unwrap());
                },
                _ => panic!("Unexpected event"),
        }
@@ -2466,7 +2511,7 @@ fn test_simple_partial_retry() {
 
        let mut route = Route {
                paths: vec![
-                       vec![RouteHop {
+                       Path { hops: vec![RouteHop {
                                pubkey: nodes[1].node.get_our_node_id(),
                                node_features: nodes[1].node.node_features(),
                                short_channel_id: chan_1_scid,
@@ -2480,8 +2525,8 @@ fn test_simple_partial_retry() {
                                channel_features: nodes[2].node.channel_features(),
                                fee_msat: 100_000_000,
                                cltv_expiry_delta: 100,
-                       }],
-                       vec![RouteHop {
+                       }], blinded_tail: None },
+                       Path { hops: vec![RouteHop {
                                pubkey: nodes[1].node.get_our_node_id(),
                                node_features: nodes[1].node.node_features(),
                                short_channel_id: chan_1_scid,
@@ -2495,7 +2540,7 @@ fn test_simple_partial_retry() {
                                channel_features: nodes[2].node.channel_features(),
                                fee_msat: 100_000_000,
                                cltv_expiry_delta: 100,
-                       }]
+                       }], blinded_tail: None }
                ],
                payment_params: Some(PaymentParameters::from_node_id(nodes[2].node.get_our_node_id(), TEST_FINAL_CLTV)),
        };
@@ -2509,7 +2554,8 @@ fn test_simple_partial_retry() {
                        final_value_msat: amt_msat / 2,
                }, Ok(route.clone()));
 
-       nodes[0].node.send_payment_with_retry(payment_hash, &Some(payment_secret), PaymentId(payment_hash.0), route_params, Retry::Attempts(1)).unwrap();
+       nodes[0].node.send_payment(payment_hash, RecipientOnionFields::secret_only(payment_secret),
+               PaymentId(payment_hash.0), route_params, Retry::Attempts(1)).unwrap();
        let htlc_updates = SendEvent::from_node(&nodes[0]);
        check_added_monitors!(nodes[0], 1);
        assert_eq!(htlc_updates.msgs.len(), 1);
@@ -2631,7 +2677,7 @@ fn test_threaded_payment_retries() {
 
        let mut route = Route {
                paths: vec![
-                       vec![RouteHop {
+                       Path { hops: vec![RouteHop {
                                pubkey: nodes[1].node.get_our_node_id(),
                                node_features: nodes[1].node.node_features(),
                                short_channel_id: chan_1_scid,
@@ -2645,8 +2691,8 @@ fn test_threaded_payment_retries() {
                                channel_features: nodes[2].node.channel_features(),
                                fee_msat: amt_msat / 1000,
                                cltv_expiry_delta: 100,
-                       }],
-                       vec![RouteHop {
+                       }], blinded_tail: None },
+                       Path { hops: vec![RouteHop {
                                pubkey: nodes[2].node.get_our_node_id(),
                                node_features: nodes[2].node.node_features(),
                                short_channel_id: chan_3_scid,
@@ -2660,13 +2706,14 @@ fn test_threaded_payment_retries() {
                                channel_features: nodes[3].node.channel_features(),
                                fee_msat: amt_msat - amt_msat / 1000,
                                cltv_expiry_delta: 100,
-                       }]
+                       }], blinded_tail: None }
                ],
                payment_params: Some(PaymentParameters::from_node_id(nodes[2].node.get_our_node_id(), TEST_FINAL_CLTV)),
        };
        nodes[0].router.expect_find_route(route_params.clone(), Ok(route.clone()));
 
-       nodes[0].node.send_payment_with_retry(payment_hash, &Some(payment_secret), PaymentId(payment_hash.0), route_params.clone(), Retry::Attempts(0xdeadbeef)).unwrap();
+       nodes[0].node.send_payment(payment_hash, RecipientOnionFields::secret_only(payment_secret),
+               PaymentId(payment_hash.0), route_params.clone(), Retry::Attempts(0xdeadbeef)).unwrap();
        check_added_monitors!(nodes[0], 2);
        let mut send_msg_events = nodes[0].node.get_and_clear_pending_msg_events();
        assert_eq!(send_msg_events.len(), 2);
@@ -2717,9 +2764,9 @@ fn test_threaded_payment_retries() {
                // we should still ultimately fail for the same reason - because we're trying to send too
                // many HTLCs at once.
                let mut new_route_params = route_params.clone();
-               previously_failed_channels.push(route.paths[0][1].short_channel_id);
+               previously_failed_channels.push(route.paths[0].hops[1].short_channel_id);
                new_route_params.payment_params.previously_failed_channels = previously_failed_channels.clone();
-               route.paths[0][1].short_channel_id += 1;
+               route.paths[0].hops[1].short_channel_id += 1;
                nodes[0].router.expect_find_route(new_route_params, Ok(route.clone()));
 
                let bs_fail_updates = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
@@ -2794,6 +2841,7 @@ fn do_no_missing_sent_on_midpoint_reload(persist_manager_with_payment: bool) {
        if let Event::PaymentSent { payment_preimage, .. } = events[1] { assert_eq!(payment_preimage, our_payment_preimage); } else { panic!(); }
        // Note that we don't get a PaymentPathSuccessful here as we leave the HTLC pending to avoid
        // the double-claim that would otherwise appear at the end of this test.
+       nodes[0].node.timer_tick_occurred();
        let as_broadcasted_txn = nodes[0].tx_broadcaster.txn_broadcasted.lock().unwrap().split_off(0);
        assert_eq!(as_broadcasted_txn.len(), 1);
 
@@ -2828,3 +2876,293 @@ fn no_missing_sent_on_midpoint_reload() {
        do_no_missing_sent_on_midpoint_reload(false);
        do_no_missing_sent_on_midpoint_reload(true);
 }
+
+fn do_claim_from_closed_chan(fail_payment: bool) {
+       // Previously, LDK would refuse to claim a payment if a channel on which the payment was
+       // received had been closed between when the HTLC was received and when we went to claim it.
+       // This makes sense in the payment case - why pay an on-chain fee to claim the HTLC when
+       // presumably the sender may retry later. Long ago it also reduced total code in the claim
+       // pipeline.
+       //
+       // However, this doesn't make sense if you're trying to do an atomic swap or some other
+       // protocol that requires atomicity with some other action - if your money got claimed
+       // elsewhere you need to be able to claim the HTLC in lightning no matter what. Further, this
+       // is an over-optimization - there should be a very, very low likelihood that a channel closes
+       // between when we receive the last HTLC for a payment and the user goes to claim the payment.
+       // Since we now have code to handle this anyway we should allow it.
+
+       // Build 4 nodes and send an MPP payment across two paths. By building a route manually set the
+       // CLTVs on the paths to different value resulting in a different claim deadline.
+       let chanmon_cfgs = create_chanmon_cfgs(4);
+       let node_cfgs = create_node_cfgs(4, &chanmon_cfgs);
+       let node_chanmgrs = create_node_chanmgrs(4, &node_cfgs, &[None, None, None, None]);
+       let mut nodes = create_network(4, &node_cfgs, &node_chanmgrs);
+
+       create_announced_chan_between_nodes(&nodes, 0, 1);
+       create_announced_chan_between_nodes_with_value(&nodes, 0, 2, 1_000_000, 0);
+       let chan_bd = create_announced_chan_between_nodes_with_value(&nodes, 1, 3, 1_000_000, 0).2;
+       create_announced_chan_between_nodes(&nodes, 2, 3);
+
+       let (payment_preimage, payment_hash, payment_secret) = get_payment_preimage_hash!(nodes[3]);
+       let mut route_params = RouteParameters {
+               payment_params: PaymentParameters::from_node_id(nodes[3].node.get_our_node_id(), TEST_FINAL_CLTV)
+                       .with_features(nodes[1].node.invoice_features()),
+               final_value_msat: 10_000_000,
+       };
+       let mut route = nodes[0].router.find_route(&nodes[0].node.get_our_node_id(), &route_params,
+               None, &nodes[0].node.compute_inflight_htlcs()).unwrap();
+       // Make sure the route is ordered as the B->D path before C->D
+       route.paths.sort_by(|a, _| if a.hops[0].pubkey == nodes[1].node.get_our_node_id() {
+               std::cmp::Ordering::Less } else { std::cmp::Ordering::Greater });
+
+       // Note that we add an extra 1 in the send pipeline to compensate for any blocks found while
+       // the HTLC is being relayed.
+       route.paths[0].hops[1].cltv_expiry_delta = TEST_FINAL_CLTV + 8;
+       route.paths[1].hops[1].cltv_expiry_delta = TEST_FINAL_CLTV + 12;
+       let final_cltv = nodes[0].best_block_info().1 + TEST_FINAL_CLTV + 8 + 1;
+
+       nodes[0].router.expect_find_route(route_params.clone(), Ok(route.clone()));
+       nodes[0].node.send_payment(payment_hash, RecipientOnionFields::secret_only(payment_secret),
+               PaymentId(payment_hash.0), route_params.clone(), Retry::Attempts(1)).unwrap();
+       check_added_monitors(&nodes[0], 2);
+       let mut send_msgs = nodes[0].node.get_and_clear_pending_msg_events();
+       send_msgs.sort_by(|a, _| {
+               let a_node_id =
+                       if let MessageSendEvent::UpdateHTLCs { node_id, .. } = a { node_id } else { panic!() };
+               let node_b_id = nodes[1].node.get_our_node_id();
+               if *a_node_id == node_b_id { std::cmp::Ordering::Less } else { std::cmp::Ordering::Greater }
+       });
+
+       assert_eq!(send_msgs.len(), 2);
+       pass_along_path(&nodes[0], &[&nodes[1], &nodes[3]], 10_000_000,
+               payment_hash, Some(payment_secret), send_msgs.remove(0), false, None);
+       let receive_event = pass_along_path(&nodes[0], &[&nodes[2], &nodes[3]], 10_000_000,
+               payment_hash, Some(payment_secret), send_msgs.remove(0), true, None);
+
+       match receive_event.unwrap() {
+               Event::PaymentClaimable { claim_deadline, .. } => {
+                       assert_eq!(claim_deadline.unwrap(), final_cltv - HTLC_FAIL_BACK_BUFFER);
+               },
+               _ => panic!(),
+       }
+
+       // Ensure that the claim_deadline is correct, with the payment failing at exactly the given
+       // height.
+       connect_blocks(&nodes[3], final_cltv - HTLC_FAIL_BACK_BUFFER - nodes[3].best_block_info().1
+               - if fail_payment { 0 } else { 2 });
+       if fail_payment {
+               // We fail the HTLC on the A->B->D path first as it expires 4 blocks earlier. We go ahead
+               // and expire both immediately, though, by connecting another 4 blocks.
+               let reason = HTLCDestination::FailedPayment { payment_hash };
+               expect_pending_htlcs_forwardable_and_htlc_handling_failed!(&nodes[3], [reason.clone()]);
+               connect_blocks(&nodes[3], 4);
+               expect_pending_htlcs_forwardable_and_htlc_handling_failed!(&nodes[3], [reason]);
+               pass_failed_payment_back(&nodes[0], &[&[&nodes[1], &nodes[3]], &[&nodes[2], &nodes[3]]], false, payment_hash, PaymentFailureReason::RecipientRejected);
+       } else {
+               nodes[1].node.force_close_broadcasting_latest_txn(&chan_bd, &nodes[3].node.get_our_node_id()).unwrap();
+               check_closed_event(&nodes[1], 1, ClosureReason::HolderForceClosed, false);
+               check_closed_broadcast(&nodes[1], 1, true);
+               let bs_tx = nodes[1].tx_broadcaster.txn_broadcasted.lock().unwrap().split_off(0);
+               assert_eq!(bs_tx.len(), 1);
+
+               mine_transaction(&nodes[3], &bs_tx[0]);
+               check_added_monitors(&nodes[3], 1);
+               check_closed_broadcast(&nodes[3], 1, true);
+               check_closed_event(&nodes[3], 1, ClosureReason::CommitmentTxConfirmed, false);
+
+               nodes[3].node.claim_funds(payment_preimage);
+               check_added_monitors(&nodes[3], 2);
+               expect_payment_claimed!(nodes[3], payment_hash, 10_000_000);
+
+               let ds_tx = nodes[3].tx_broadcaster.txn_broadcasted.lock().unwrap().split_off(0);
+               assert_eq!(ds_tx.len(), 1);
+               check_spends!(&ds_tx[0], &bs_tx[0]);
+
+               mine_transactions(&nodes[1], &[&bs_tx[0], &ds_tx[0]]);
+               check_added_monitors(&nodes[1], 1);
+               expect_payment_forwarded!(nodes[1], nodes[0], nodes[3], Some(1000), false, true);
+
+               let bs_claims = nodes[1].node.get_and_clear_pending_msg_events();
+               check_added_monitors(&nodes[1], 1);
+               assert_eq!(bs_claims.len(), 1);
+               if let MessageSendEvent::UpdateHTLCs { updates, .. } = &bs_claims[0] {
+                       nodes[0].node.handle_update_fulfill_htlc(&nodes[1].node.get_our_node_id(), &updates.update_fulfill_htlcs[0]);
+                       commitment_signed_dance!(nodes[0], nodes[1], updates.commitment_signed, false, true);
+               } else { panic!(); }
+
+               expect_payment_sent!(nodes[0], payment_preimage);
+
+               let ds_claim_msgs = nodes[3].node.get_and_clear_pending_msg_events();
+               assert_eq!(ds_claim_msgs.len(), 1);
+               let cs_claim_msgs = if let MessageSendEvent::UpdateHTLCs { updates, .. } = &ds_claim_msgs[0] {
+                       nodes[2].node.handle_update_fulfill_htlc(&nodes[3].node.get_our_node_id(), &updates.update_fulfill_htlcs[0]);
+                       let cs_claim_msgs = nodes[2].node.get_and_clear_pending_msg_events();
+                       check_added_monitors(&nodes[2], 1);
+                       commitment_signed_dance!(nodes[2], nodes[3], updates.commitment_signed, false, true);
+                       expect_payment_forwarded!(nodes[2], nodes[0], nodes[3], Some(1000), false, false);
+                       cs_claim_msgs
+               } else { panic!(); };
+
+               assert_eq!(cs_claim_msgs.len(), 1);
+               if let MessageSendEvent::UpdateHTLCs { updates, .. } = &cs_claim_msgs[0] {
+                       nodes[0].node.handle_update_fulfill_htlc(&nodes[2].node.get_our_node_id(), &updates.update_fulfill_htlcs[0]);
+                       commitment_signed_dance!(nodes[0], nodes[2], updates.commitment_signed, false, true);
+               } else { panic!(); }
+
+               expect_payment_path_successful!(nodes[0]);
+       }
+}
+
+#[test]
+fn claim_from_closed_chan() {
+       do_claim_from_closed_chan(true);
+       do_claim_from_closed_chan(false);
+}
+
+fn do_test_payment_metadata_consistency(do_reload: bool, do_modify: bool) {
+       // Check that a payment metadata received on one HTLC that doesn't match the one received on
+       // another results in the HTLC being rejected.
+       //
+       // We first set up a diamond shaped network, allowing us to split a payment into two HTLCs, the
+       // first of which we'll deliver and the second of which we'll fail and then re-send with
+       // modified payment metadata, which will in turn result in it being failed by the recipient.
+       let chanmon_cfgs = create_chanmon_cfgs(4);
+       let node_cfgs = create_node_cfgs(4, &chanmon_cfgs);
+       let mut config = test_default_channel_config();
+       config.channel_handshake_config.max_inbound_htlc_value_in_flight_percent_of_channel = 50;
+       let node_chanmgrs = create_node_chanmgrs(4, &node_cfgs, &[None, Some(config), Some(config), Some(config)]);
+
+       let persister;
+       let new_chain_monitor;
+       let nodes_0_deserialized;
+
+       let mut nodes = create_network(4, &node_cfgs, &node_chanmgrs);
+
+       create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0);
+       let chan_id_bd = create_announced_chan_between_nodes_with_value(&nodes, 1, 3, 1_000_000, 0).2;
+       create_announced_chan_between_nodes_with_value(&nodes, 0, 2, 1_000_000, 0);
+       let chan_id_cd = create_announced_chan_between_nodes_with_value(&nodes, 2, 3, 1_000_000, 0).2;
+
+       // Pay more than half of each channel's max, requiring MPP
+       let amt_msat = 750_000_000;
+       let (payment_preimage, payment_hash, payment_secret) = get_payment_preimage_hash!(nodes[3], Some(amt_msat));
+       let payment_id = PaymentId(payment_hash.0);
+       let payment_metadata = vec![44, 49, 52, 142];
+
+       let payment_params = PaymentParameters::from_node_id(nodes[3].node.get_our_node_id(), TEST_FINAL_CLTV)
+               .with_features(nodes[1].node.invoice_features());
+       let mut route_params = RouteParameters {
+               payment_params,
+               final_value_msat: amt_msat,
+       };
+
+       // Send the MPP payment, delivering the updated commitment state to nodes[1].
+       nodes[0].node.send_payment(payment_hash, RecipientOnionFields {
+                       payment_secret: Some(payment_secret), payment_metadata: Some(payment_metadata),
+               }, payment_id, route_params.clone(), Retry::Attempts(1)).unwrap();
+       check_added_monitors!(nodes[0], 2);
+
+       let mut send_events = nodes[0].node.get_and_clear_pending_msg_events();
+       assert_eq!(send_events.len(), 2);
+       let first_send = SendEvent::from_event(send_events.pop().unwrap());
+       let second_send = SendEvent::from_event(send_events.pop().unwrap());
+
+       let (b_recv_ev, c_recv_ev) = if first_send.node_id == nodes[1].node.get_our_node_id() {
+               (&first_send, &second_send)
+       } else {
+               (&second_send, &first_send)
+       };
+       nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &b_recv_ev.msgs[0]);
+       commitment_signed_dance!(nodes[1], nodes[0], b_recv_ev.commitment_msg, false, true);
+
+       expect_pending_htlcs_forwardable!(nodes[1]);
+       check_added_monitors(&nodes[1], 1);
+       let b_forward_ev = SendEvent::from_node(&nodes[1]);
+       nodes[3].node.handle_update_add_htlc(&nodes[1].node.get_our_node_id(), &b_forward_ev.msgs[0]);
+       commitment_signed_dance!(nodes[3], nodes[1], b_forward_ev.commitment_msg, false, true);
+
+       expect_pending_htlcs_forwardable!(nodes[3]);
+
+       // Before delivering the second MPP HTLC to nodes[2], disconnect nodes[2] and nodes[3], which
+       // will result in nodes[2] failing the HTLC back.
+       nodes[2].node.peer_disconnected(&nodes[3].node.get_our_node_id());
+       nodes[3].node.peer_disconnected(&nodes[2].node.get_our_node_id());
+
+       nodes[2].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &c_recv_ev.msgs[0]);
+       commitment_signed_dance!(nodes[2], nodes[0], c_recv_ev.commitment_msg, false, true);
+
+       let cs_fail = get_htlc_update_msgs(&nodes[2], &nodes[0].node.get_our_node_id());
+       nodes[0].node.handle_update_fail_htlc(&nodes[2].node.get_our_node_id(), &cs_fail.update_fail_htlcs[0]);
+       commitment_signed_dance!(nodes[0], nodes[2], cs_fail.commitment_signed, false, true);
+
+       let payment_fail_retryable_evs = nodes[0].node.get_and_clear_pending_events();
+       assert_eq!(payment_fail_retryable_evs.len(), 2);
+       if let Event::PaymentPathFailed { .. } = payment_fail_retryable_evs[0] {} else { panic!(); }
+       if let Event::PendingHTLCsForwardable { .. } = payment_fail_retryable_evs[1] {} else { panic!(); }
+
+       // Before we allow the HTLC to be retried, optionally change the payment_metadata we have
+       // stored for our payment.
+       if do_modify {
+               nodes[0].node.test_set_payment_metadata(payment_id, Some(Vec::new()));
+       }
+
+       // Optionally reload nodes[3] to check that the payment_metadata is properly serialized with
+       // the payment state.
+       if do_reload {
+               let mon_bd = get_monitor!(nodes[3], chan_id_bd).encode();
+               let mon_cd = get_monitor!(nodes[3], chan_id_cd).encode();
+               reload_node!(nodes[3], config, &nodes[3].node.encode(), &[&mon_bd, &mon_cd],
+                       persister, new_chain_monitor, nodes_0_deserialized);
+               nodes[1].node.peer_disconnected(&nodes[3].node.get_our_node_id());
+               reconnect_nodes(&nodes[1], &nodes[3], (false, false), (0, 0), (0, 0), (0, 0), (0, 0), (0, 0), (false, false));
+       }
+       reconnect_nodes(&nodes[2], &nodes[3], (true, true), (0, 0), (0, 0), (0, 0), (0, 0), (0, 0), (false, false));
+
+       // Create a new channel between C and D as A will refuse to retry on the existing one because
+       // it just failed.
+       let chan_id_cd_2 = create_announced_chan_between_nodes_with_value(&nodes, 2, 3, 1_000_000, 0).2;
+
+       // Now retry the failed HTLC.
+       nodes[0].node.process_pending_htlc_forwards();
+       check_added_monitors(&nodes[0], 1);
+       let as_resend = SendEvent::from_node(&nodes[0]);
+       nodes[2].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &as_resend.msgs[0]);
+       commitment_signed_dance!(nodes[2], nodes[0], as_resend.commitment_msg, false, true);
+
+       expect_pending_htlcs_forwardable!(nodes[2]);
+       check_added_monitors(&nodes[2], 1);
+       let cs_forward = SendEvent::from_node(&nodes[2]);
+       nodes[3].node.handle_update_add_htlc(&nodes[2].node.get_our_node_id(), &cs_forward.msgs[0]);
+       commitment_signed_dance!(nodes[3], nodes[2], cs_forward.commitment_msg, false, true);
+
+       // Finally, check that nodes[3] does the correct thing - either accepting the payment or, if
+       // the payment metadata was modified, failing only the one modified HTLC and retaining the
+       // other.
+       if do_modify {
+               expect_pending_htlcs_forwardable_ignore!(nodes[3]);
+               nodes[3].node.process_pending_htlc_forwards();
+               expect_pending_htlcs_forwardable_conditions(nodes[3].node.get_and_clear_pending_events(),
+                       &[HTLCDestination::FailedPayment {payment_hash}]);
+               nodes[3].node.process_pending_htlc_forwards();
+
+               check_added_monitors(&nodes[3], 1);
+               let ds_fail = get_htlc_update_msgs(&nodes[3], &nodes[2].node.get_our_node_id());
+
+               nodes[2].node.handle_update_fail_htlc(&nodes[3].node.get_our_node_id(), &ds_fail.update_fail_htlcs[0]);
+               commitment_signed_dance!(nodes[2], nodes[3], ds_fail.commitment_signed, false, true);
+               expect_pending_htlcs_forwardable_conditions(nodes[2].node.get_and_clear_pending_events(),
+                       &[HTLCDestination::NextHopChannel { node_id: Some(nodes[3].node.get_our_node_id()), channel_id: chan_id_cd_2 }]);
+       } else {
+               expect_pending_htlcs_forwardable!(nodes[3]);
+               expect_payment_claimable!(nodes[3], payment_hash, payment_secret, amt_msat);
+               claim_payment_along_route(&nodes[0], &[&[&nodes[1], &nodes[3]], &[&nodes[2], &nodes[3]]], false, payment_preimage);
+       }
+}
+
+#[test]
+fn test_payment_metadata_consistency() {
+       do_test_payment_metadata_consistency(true, true);
+       do_test_payment_metadata_consistency(true, false);
+       do_test_payment_metadata_consistency(false, true);
+       do_test_payment_metadata_consistency(false, false);
+}